A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.
Chromatographic techniques in which the mobile phase is a liquid.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.
A solventless sample preparation method, invented in 1989, that uses a fused silica fiber which is coated with a stationary phase. It is used for sample cleanup before using other analytical methods.
The systematic identification and quantitation of all the metabolic products of a cell, tissue, organ, or organism under varying conditions. The METABOLOME of a cell or organism is a dynamic collection of metabolites which represent its net response to current conditions.
A mass spectrometry technique using two (MS/MS) or more mass analyzers. With two in tandem, the precursor ions are mass-selected by a first mass analyzer, and focused into a collision region where they are then fragmented into product ions which are then characterized by a second mass analyzer. A variety of techniques are used to separate the compounds, ionize them, and introduce them to the first mass analyzer. For example, for in GC-MS/MS, GAS CHROMATOGRAPHY-MASS SPECTROMETRY is involved in separating relatively small compounds by GAS CHROMATOGRAPHY prior to injecting them into an ionization chamber for the mass selection.
The dynamic collection of metabolites which represent a cell's or organism's net metabolic response to current conditions.
Perianal glands, also known as hepatoid glands, are sebaceous glands located in the perianal region of many mammals, including humans, that produce and secret lubricating oils for skin protection and cleanliness.
A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.
Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.
A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.
A plant species of the genus OCIMUM, family LAMIACEAE. It is a condiment with carminative properties.
Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Unsaturated androstane derivatives which are substituted with two hydroxy groups in any position in the ring system.
Compounds used extensively as acetylation, oxidation and dehydrating agents and in the modification of proteins and enzymes.
Detection of drugs that have been abused, overused, or misused, including legal and illegal drugs. Urine screening is the usual method of detection.
The thick green-to-black mucilaginous material found in the intestines of a full-term fetus. It consists of secretions of the INTESTINAL GLANDS; BILE PIGMENTS; FATTY ACIDS; AMNIOTIC FLUID; and intrauterine debris. It constitutes the first stools passed by a newborn.
Deuterium. The stable isotope of hydrogen. It has one neutron and one proton in the nucleus.
Illegitimate use of substances for a desired effect in competitive sports. It includes humans and animals.
Isoprostanes derived from the free radical oxidation of ARACHIDONIC ACID. Although similar in structure to enzymatically synthesized prostaglandin F2alpha (DINOPROST), they occur through non-enzymatic oxidation of cell membrane lipids.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.
The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.
Organic compounds containing the carboxy group (-COOH). This group of compounds includes amino acids and fatty acids. Carboxylic acids can be saturated, unsaturated, or aromatic.
Eicosatetraenoic acids substituted in any position by one or more hydroxy groups. They are important intermediates in a series of biosynthetic processes leading from arachidonic acid to a number of biologically active compounds such as prostaglandins, thromboxanes, and leukotrienes.
The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)
Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
"Esters are organic compounds that result from the reaction between an alcohol and a carboxylic acid, playing significant roles in various biological processes and often used in pharmaceutical synthesis."
A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)
A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)
Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
The characteristic 3-dimensional shape of a carbohydrate.
Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.
The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.
An enzyme of the oxidoreductase class primarily found in PLANTS. It catalyzes reactions between linoleate and other fatty acids and oxygen to form hydroperoxy-fatty acid derivatives.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)
The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.
Arachidonic acids are polyunsaturated fatty acids, specifically a type of omega-6 fatty acid, that are essential for human nutrition and play crucial roles in various biological processes, including inflammation, immunity, and cell signaling. They serve as precursors to eicosanoids, which are hormone-like substances that mediate a wide range of physiological responses.
An unsaturated, essential fatty acid. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is formed by the synthesis from dietary linoleic acid and is a precursor in the biosynthesis of prostaglandins, thromboxanes, and leukotrienes.
The process of cleaving a chemical compound by the addition of a molecule of water.
The systematic study of the complete complement of proteins (PROTEOME) of organisms.
A naturally occurring prostaglandin that has oxytocic, luteolytic, and abortifacient activities. Due to its vasocontractile properties, the compound has a variety of other biological actions.
A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.
FATTY ACIDS in which the carbon chain contains one or more double or triple carbon-carbon bonds.
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.
A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Elements of limited time intervals, contributing to particular results or situations.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.
The rate dynamics in chemical or physical systems.
A plant family of the order Eucommiales, subclass Hamamelidae, class Magnoliopsida (some botanists have classified this in the order Hamamelidales or Urticales). Eucomia is an elmlike tree of central and eastern China. Leaves are alternate; deciduous flowers are solitary and unisexual and lack petals and sepals. The male flowers have 6 to 10 stamens and female flowers have one ovary of two carpels, one of which aborts during development so the fruit (a dry, winged structure) contains only one seed. The latex is a source of RUBBER. Tochu tea is an aqueous extract of Eucommia ulmoides leaves and a popular beverage in Japan. (Mutat Res 1997 Jan 15;388(1):7-20).
Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.
Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.
Five-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.
Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.
A 20-carbon-chain fatty acid, unsaturated at positions 8, 11, and 14. It differs from arachidonic acid, 5,8,11,14-eicosatetraenoic acid, only at position 5.
A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.
The protein complement of an organism coded for by its genome.
Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.
Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.
A plant genus of the family CRASSULACEAE. Members contain rhodioloside. This roseroot is unrelated to the familiar rose (ROSA). Some species in this genus are called stonecrop which is also a common name for SEDUM.
Any tests done on exhaled air.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.
Pyrolysis of organic compounds at the temperature of a hydrogen-air flame to produce ionic intermediates which can be collected and the resulting ion current measured by gas chromatography.
'Sugar acids' are organic compounds derived from sugars through various processes, characterized by the presence of both a carboxyl group (-COOH) and a hydroxyl group (-OH) in their molecular structure, often found in food sources like fruits and used in industries such as food, pharmaceutical, and cosmetic.
Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
A chromatography technique in which the stationary phase is composed of a non-polar substance with a polar mobile phase, in contrast to normal-phase chromatography in which the stationary phase is a polar substance with a non-polar mobile phase.
A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.
Polyhydric alcohols having no more than one hydroxy group attached to each carbon atom. They are formed by the reduction of the carbonyl group of a sugar to a hydroxyl group.(From Dorland, 28th ed)
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.
Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.
Inorganic or organic compounds that contain sulfur as an integral part of the molecule.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Chemicals that kill or inhibit the growth of fungi in agricultural applications, on wood, plastics, or other materials, in swimming pools, etc.
Compounds consisting of benzene rings linked to each other in either ortho, meta or para positions. Permitted are any substitutions, but ring fusion to any of the benzene rings is not allowed.
An extraction method that separates analytes using a solid phase and a liquid phase. It is used for preparative sample cleanup before analysis by CHROMATOGRAPHY and other analytical methods.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
Electrophoresis in which a second perpendicular electrophoretic transport is performed on the separate components resulting from the first electrophoresis. This technique is usually performed on polyacrylamide gels.
Methods for assessing flow through a system by injection of a known quantity of an indicator, such as a dye, radionuclide, or chilled liquid, into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
Hydrocarbons are organic compounds consisting entirely of hydrogen and carbon atoms, forming the basis of classes such as alkanes, alkenes, alkynes, and aromatic hydrocarbons, which play a vital role in energy production and chemical synthesis.
A mass-spectrometric technique that is used for microscopic chemical analysis. A beam of primary ions with an energy of 5-20 kiloelectronvolts (keV) bombards a small spot on the surface of the sample under ultra-high vacuum conditions. Positive and negative secondary ions sputtered from the surface are analyzed in a mass spectrometer in regards to their mass-to-charge ratio. Digital imaging can be generated from the secondary ion beams and their intensity can be measured. Ionic images can be correlated with images from light or other microscopy providing useful tools in the study of molecular and drug actions.
Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)
The sum of the weight of all the atoms in a molecule.
Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.
An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.
A mass spectrometric technique that is used for the analysis of a wide range of biomolecules, such as glycoalkaloids, glycoproteins, polysaccharides, and peptides. Positive and negative fast atom bombardment spectra are recorded on a mass spectrometer fitted with an atom gun with xenon as the customary beam. The mass spectra obtained contain molecular weight recognition as well as sequence information.
Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.
Glycosides of GLUCURONIC ACID formed by the reaction of URIDINE DIPHOSPHATE GLUCURONIC ACID with certain endogenous and exogenous substances. Their formation is important for the detoxification of drugs, steroid excretion and BILIRUBIN metabolism to a more water-soluble compound that can be eliminated in the URINE and BILE.
Polysaccharides are complex carbohydrates consisting of long, often branched chains of repeating monosaccharide units joined together by glycosidic bonds, which serve as energy storage molecules (e.g., glycogen), structural components (e.g., cellulose), and molecular recognition sites in various biological systems.
An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
Glyoxal is a chemical compound, an organic dicarbonyl compound, with the formula O=C-CH-CH=O, which is a colorless liquid that can be used as a reagent in various chemical reactions, including the formation of Schiff bases and other adducts with amines.
Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.
Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Mycolic acids are complex, long-chain fatty acids that are a major component of the cell wall of Mycobacterium species, including the causative agents of tuberculosis and leprosy, providing them with unique characteristics such as resistance to acid-alkali stability, pigmentation, and protection against host immune responses.
Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.
Drugs intended for human or veterinary use, presented in their finished dosage form. Included here are materials used in the preparation and/or formulation of the finished dosage form.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.
Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.
A group of compounds derived from ammonia by substituting organic radicals for the hydrogens. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Proteins prepared by recombinant DNA technology.
The development and use of techniques and equipment to study or perform chemical reactions, with small quantities of materials, frequently less than a milligram or a milliliter.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
Separation of a mixture in successive stages, each stage removing from the mixture some proportion of one of the substances, for example by differential solubility in water-solvent mixtures. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.
Fatty acid derivatives that have specificity for CANNABINOID RECEPTORS. They are structurally distinct from CANNABINOIDS and were originally discovered as a group of endogenous CANNABINOID RECEPTOR AGONISTS.
Proteins found in any species of bacterium.
The giving of drugs, chemicals, or other substances by mouth.
A statistical means of summarizing information from a series of measurements on one individual. It is frequently used in clinical pharmacology where the AUC from serum levels can be interpreted as the total uptake of whatever has been administered. As a plot of the concentration of a drug against time, after a single dose of medicine, producing a standard shape curve, it is a means of comparing the bioavailability of the same drug made by different companies. (From Winslade, Dictionary of Clinical Research, 1992)
Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
The application of medical knowledge to questions of law.
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
A cytochrome P-450 suptype that has specificity for a broad variety of lipophilic compounds, including STEROIDS; FATTY ACIDS; and XENOBIOTICS. This enzyme has clinical significance due to its ability to metabolize a diverse array of clinically important drugs such as CYCLOSPORINE; VERAPAMIL; and MIDAZOLAM. This enzyme also catalyzes the N-demethylation of ERYTHROMYCIN.
Sequential operating programs and data which instruct the functioning of a digital computer.
A research technique to measure solvent exposed regions of molecules that is used to provide insight about PROTEIN CONFORMATION.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.
Amides composed of unsaturated aliphatic FATTY ACIDS linked with AMINES by an amide bond. They are most prominent in ASTERACEAE; PIPERACEAE; and RUTACEAE; and also found in ARISTOLOCHIACEAE; BRASSICACEAE; CONVOLVULACEAE; EUPHORBIACEAE; MENISPERMACEAE; POACEAE; and SOLANACEAE. They are recognized by their pungent taste and for causing numbing and salivation.

Analysis of gabapentin in serum and plasma by solid-phase extraction and gas chromatography-mass spectrometry for therapeutic drug monitoring. (1/5623)

A simple method for the determination of gabapentin (Neurontin) is described. The method uses solid-phase extraction by disk column and derivatization followed by gas chromatographic-mass spectrometric analysis. The single-step derivatization with MTBSTFA produces a t-BDMS derivative of both the carboxylic and amine moieties of the molecule. Each step of the procedure was optimized to assure reliable performance of the method. The assay limit of detection was 0.1 microg/mL with a linear range from 1.0 to 35 microg/mL. Within-run (n = 3) and between-run (n = 40) coefficients of variation were less than 8.2 and 15.9%, respectively. The method has proven reliable in routine production for more than a year, producing clean chromatography with unique ion fragments, consistent ion mass ratios, and no interferences. Statistical analysis of the gabapentin concentrations measured in 1020 random specimens over a 2-month period showed a mean concentration of 6.07 microg/mL with a standard deviation of 5.28.  (+info)

Solid-phase microextraction for cannabinoids analysis in hair and its possible application to other drugs. (2/5623)

This paper describes the application of solid-phase microextraction (SPME) to cannabis testing in hair. Fifty milligrams of hair was washed with petroleum ether, hydrolyzed with NaOH, neutralized, deuterated internal standard was added and directly submitted to SPME. The SPME was analyzed by GC-MS. The limit of detection was 0.1 ng/mg for cannabinol (CBN) and delta9-tetrahydrocannabinol (THC) and 0.2 ng/mg for cannabidiol (CBD). THC was detected in a range spanning from 0.1 to 0.7 ng/mg. CBD concentrations ranged from 0.7 to 14.1 ng/mg, and CBN concentrations ranged from 0.4 to 0.7 ng/mg. The effectiveness of different decontamination procedures was also studied on passively contaminated hair. The proposed method is also suitable for the analysis of methadone in hair; cocaine and cocaethylene can be detected in hair with SPME extraction after enzymatic hydrolysis.  (+info)

Highly sensitive quantitation of methamphetamine by time-resolved fluoroimmunoassay using a new europium chelate as a label. (3/5623)

A simple and highly sensitive time-resolved fluoroimmunoassay of methamphetamine (MA) using a new fluorescent europium chelate (BHHCT-Eu3+) as a label is described. Two variations of competitive immunoassay were attempted. In the first (one-step) assay, microtiter plates coated with anti-MA were used, and the new label was bound to a conjugate of bovine serum albumin and N-(4-aminobutyl)-MA (MA-BSA). In the second (two-step) assay, instead of the labeled MA-BSA, biotinylated MA-BSA and BHHCT-Eu3+-labeled streptavidin-BSA were used. The lowest measurable concentrations of MA for the one-step and the two-step methods were 1 ng/mL (25 pg/assay) and 1 pg/mL (25 fg/assay), respectively. These were 10 to 1000 times superior to the detection limits of MA in any other immunoassay. Intra-assay coefficient of variation was approximately 2-8% at eight different concentrations (n = 4). Analysis of 34 urine samples with the new method and conventional gas chromatography showed a good correlation (r = 0.954). The high detectability of the present assay also enabled segmental hair analysis with a few centimeters of a hair.  (+info)

Cocaine metabolite kinetics in the newborn. (4/5623)

The study goal was to determine the half-life elimination of cocaine and benzoylecgonine (BZE) in the newborn. Three 0.3-mL blood samples were collected during the first day of life. Urine was collected once daily. Cocaine and BZE concentrations were determined by gas chromatography-mass spectrometry. An extraction method was developed for measuring low concentrations of cocaine and BZE in small (0.1 mL) blood samples. Cocaine had a half-life of 11.6 h in one subject. The half-life of BZE during the first day of life, based on blood data in 13 subjects, was 16 h (95% confidence interval [CI], 12.8 to 21.4 h). The half-life of BZE during the first week of life, based on urine data in 16 subjects, was 11.2 h (95% CI, 10.1 to 11.8 h). The novel extraction method for small blood sample volumes should be applicable to other basic drugs.  (+info)

The urinary elimination profiles of diazepam and its metabolites, nordiazepam, temazepam, and oxazepam, in the equine after a 10-mg intramuscular dose. (5/5623)

A method for the extraction of diazepam and its metabolites (nordiazepam, temazepam, and oxazepam) from equine urine and serum and their quantitation and confirmation by liquid chromatography-tandem mass spectrometry is presented. Valium, a formulation of diazepam, was administered at a dose of 10 mg intramuscularly to four standard-bred mares. Diazepam is extensively metabolized in the horse to nordiazepam, temazepam, and oxazepam. Diazepam urinary concentrations were found to be less than 6 ng/mL. Nordiazepam was found to be mainly in its glucuronide-conjugated form and was measured out to a collection time of 53-55 h. Oxazepam and temazepam were entirely conjugated, and their urinary concentrations were measured out to collection times of 121 h and 77-79 h, respectively. Diazepam and nordiazepam were measured in equine postadministration serum out to collection times of 6 and 54 h, respectively. Oxazepam and temazepam were not detected in postadministration serum.  (+info)

Semiautomated preparation of 3,5,6-trichloro-2-pyridinol in human urine using a Zymate XP laboratory robot with quantitative determination by gas chromatography-negative-ion chemical ionization mass spectrometry. (6/5623)

A rapid and sensitive semiautomated method was developed for quantitation of the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCP) in human urine. A Zymark Zymate XP laboratory robotics system was used to mix urine samples, transfer aliquots, add the stable-isotope-labeled TCP internal standard (13C2- or 13C2,15N-), and liberate conjugates of TCP from urine via acid hydrolysis. Samples were manually extracted into toluene, derivatized, and analyzed by gas chromatography-negative-ion chemical ionization mass spectrometry. Determination of the metabolic TCP was performed by selected ion monitoring of the dichloropyridinol fragment ions: m/z 161 for TCP and m/z 165 for 13C2-TCP or m/z 168 for 13C2,15N-TCP. Interday precision and accuracy were demonstrated over 3 years of analyses using the 13C2-TCP internal standard, with an average recovery from fortified urine samples of 93+/-12% (N = 54, concentration range 1-140 ng/mL). The method was found to be linear over the range of 0.5 to 200 ng/mL, and the limit of detection for TCP in urine was estimated to be 0.2 ng/mL with a limit of quantitation of 1 ng/mL. The effect of solids distribution on the concentration of TCP in the thawed urine samples was examined, and the results indicated that homogeneous distribution is critical for quantitation. The precision and accuracy of the automated method with respect to the transfer of homgeneous urine aliquots and delivery of internal standard yielded equivalent or improved results over the manual techniques. Overall, this method is more simple than existing methodologies, and it yields results with improved precision, accuracy, and sensitivity over previously developed methods.  (+info)

Determination of pyrolysis products of smoked methamphetamine mixed with tobacco by tandem mass spectrometry. (7/5623)

This study examines the pyrolysis products of smoked methamphetamine mixed with tobacco that was trapped with a C8 adsorbent cartridge and then detected by gas chromatography-tandem mass spectrometry. According to the results, the mainstream smoke contains 2-methylpropyl-benzene, 2-chloropropyl-benzene, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 3-ethyl-phenol, methamphetamine, dimethylamphetamine, hydroquinone, 3-methyl-5-(1-methylethyl)-methylcarbamate phenol, N-methyl-N-(2-phenylethyl)-acetamide, 4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexene-1-one, propanoic acid, N-acetylmethamphetamine, phenyl ester, and furfurylmethylamphetamine. In addition, the compounds in sidestream smoke are 2-propenyl benzene, phenylacetone, methamphetamine, dimethylamphetamine, benzyl methyl ketoxime, 3,4-dihydro-2-naphthalenone, N-folmyamphetamine, N-acetylamphetamine, bibenzyl, N-folmylmethamphetamine, N-acetylmethamphetamine, N-propionymethamphetamine, and furfurylmethylamphetamine. Moreover, the presence of methamphetamine promotes the oxidation of the tobacco components.  (+info)

Identification and quantification of cocaine N-oxide: a thermally labile metabolite of cocaine. (8/5623)

In this article, we report the identification and quantitation of cocaine N-oxide (CNO), a thermally labile oxidative metabolite, from both animal and human samples. The concentration of CNO is similar to the concentrations of cocaine in the samples analyzed. The technique used for the determination of CNO in this study is liquid chromatography-electrospray ionization mass spectrometry, which is necessary because CNO is converted to cocaine upon heating. This includes simple heating of aqueous solutions to temperatures in excess of 100 degrees C and analysis by gas chromatography-mass spectrometry (GC-MS), in which CNO is converted to cocaine in the injection port. The thermal conversion of CNO to cocaine is estimated to cause an over-reporting of cocaine levels by 10-20% when using GC-MS.  (+info)

Gas Chromatography-Mass Spectrometry (GC-MS) is a powerful analytical technique that combines the separating power of gas chromatography with the identification capabilities of mass spectrometry. This method is used to separate, identify, and quantify different components in complex mixtures.

In GC-MS, the mixture is first vaporized and carried through a long, narrow column by an inert gas (carrier gas). The various components in the mixture interact differently with the stationary phase inside the column, leading to their separation based on their partition coefficients between the mobile and stationary phases. As each component elutes from the column, it is then introduced into the mass spectrometer for analysis.

The mass spectrometer ionizes the sample, breaks it down into smaller fragments, and measures the mass-to-charge ratio of these fragments. This information is used to generate a mass spectrum, which serves as a unique "fingerprint" for each compound. By comparing the generated mass spectra with reference libraries or known standards, analysts can identify and quantify the components present in the original mixture.

GC-MS has wide applications in various fields such as forensics, environmental analysis, drug testing, and research laboratories due to its high sensitivity, specificity, and ability to analyze volatile and semi-volatile compounds.

Mass spectrometry (MS) is an analytical technique used to identify and quantify the chemical components of a mixture or compound. It works by ionizing the sample, generating charged molecules or fragments, and then measuring their mass-to-charge ratio in a vacuum. The resulting mass spectrum provides information about the molecular weight and structure of the analytes, allowing for identification and characterization.

In simpler terms, mass spectrometry is a method used to determine what chemicals are present in a sample and in what quantities, by converting the chemicals into ions, measuring their masses, and generating a spectrum that shows the relative abundances of each ion type.

Chromatography, gas (GC) is a type of chromatographic technique used to separate, identify, and analyze volatile compounds or vapors. In this method, the sample mixture is vaporized and carried through a column packed with a stationary phase by an inert gas (carrier gas). The components of the mixture get separated based on their partitioning between the mobile and stationary phases due to differences in their adsorption/desorption rates or solubility.

The separated components elute at different times, depending on their interaction with the stationary phase, which can be detected and quantified by various detection systems like flame ionization detector (FID), thermal conductivity detector (TCD), electron capture detector (ECD), or mass spectrometer (MS). Gas chromatography is widely used in fields such as chemistry, biochemistry, environmental science, forensics, and food analysis.

Liquid chromatography (LC) is a type of chromatography technique used to separate, identify, and quantify the components in a mixture. In this method, the sample mixture is dissolved in a liquid solvent (the mobile phase) and then passed through a stationary phase, which can be a solid or a liquid that is held in place by a solid support.

The components of the mixture interact differently with the stationary phase and the mobile phase, causing them to separate as they move through the system. The separated components are then detected and measured using various detection techniques, such as ultraviolet (UV) absorbance or mass spectrometry.

Liquid chromatography is widely used in many areas of science and medicine, including drug development, environmental analysis, food safety testing, and clinical diagnostics. It can be used to separate and analyze a wide range of compounds, from small molecules like drugs and metabolites to large biomolecules like proteins and nucleic acids.

High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.

In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.

HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.

Volatile Organic Compounds (VOCs) are organic chemicals that have a low boiling point and easily evaporate at room temperature. They can be liquids or solids. VOCs include a variety of chemicals, such as benzene, toluene, xylene, and formaldehyde, which are found in many household products, including paints, paint strippers, and other solvents; cleaning supplies; pesticides; building materials and furnishings; office equipment such as copiers and printers, correction fluids and carbonless copy paper; and glues and adhesives.

VOCs can cause both short- and long-term health effects. Short-term exposure to high levels of VOCs can cause headaches, dizziness, visual disturbances, and memory problems. Long-term exposure can cause damage to the liver, kidneys, and central nervous system. Some VOCs are also suspected or known carcinogens.

It is important to properly use, store, and dispose of products that contain VOCs to minimize exposure. Increasing ventilation by opening windows and doors or using fans can also help reduce exposure to VOCs.

Solid-phase microextraction (SPME) is an advanced technique used in analytical chemistry for the preparation and extraction of samples. It's not exclusively a medical term, but it does have applications in clinical and medical research. Here's a definition:

Solid-phase microextraction (SPME) is a solvent-free sample preparation technique that integrates sampling, extraction, concentration, and cleanup into a single step. It involves the use of a fused-silica fiber, which is coated with a thin layer of a stationary phase, such as polydimethylsiloxane (PDMS) or polyacrylate. This fiber is exposed to the sample matrix, allowing the analytes (compounds of interest) to be adsorbed or absorbed onto the coating. After the extraction step, the fiber is then inserted into a gas chromatograph or high-performance liquid chromatograph for analysis. SPME is widely used in various fields, including environmental monitoring, food analysis, and biomedical research, due to its simplicity, rapidity, and low cost. In the medical field, it can be applied for the analysis of drugs, metabolites, or other compounds in biological samples such as blood, urine, or tissue.

Metabolomics is a branch of "omics" sciences that deals with the comprehensive and quantitative analysis of all metabolites, which are the small molecule intermediates and products of metabolism, in a biological sample. It involves the identification and measurement of these metabolites using various analytical techniques such as mass spectrometry and nuclear magnetic resonance spectroscopy. The resulting data provides a functional readout of the physiological state of an organism, tissue or cell, and can be used to identify biomarkers of disease, understand drug action and toxicity, and reveal new insights into metabolic pathways and regulatory networks.

Tandem mass spectrometry (MS/MS) is a technique used to identify and quantify specific molecules, such as proteins or metabolites, within complex mixtures. This method uses two or more sequential mass analyzers to first separate ions based on their mass-to-charge ratio and then further fragment the selected ions into smaller pieces for additional analysis. The fragmentation patterns generated in MS/MS experiments can be used to determine the structure and identity of the original molecule, making it a powerful tool in various fields such as proteomics, metabolomics, and forensic science.

The metabolome is the complete set of small molecule metabolites, such as carbohydrates, lipids, nucleic acids, and amino acids, present in a biological sample at a given moment. It reflects the physiological state of a cell, tissue, or organism and provides information about the biochemical processes that are taking place. The metabolome is dynamic and constantly changing due to various factors such as genetics, environment, diet, and disease. Studying the metabolome can help researchers understand the underlying mechanisms of health and disease and develop diagnostic tools and treatments for various medical conditions.

Perianal glands, also known as hepatoid glands or circumanal glands, are specialized sebaceous glands located in the perianal region of many mammals, including dogs and cats. These glands are found in the skin around the anus and are responsible for producing a scent that is unique to each individual animal. The secretions from these glands play a role in territorial marking and communication.

In humans, there are no true perianal glands, but there are some sweat glands located in the perianal region that can sometimes become inflamed or infected, leading to conditions such as hidradenitis suppurativa or perianal abscesses. However, these conditions are not related to the perianal glands found in animals.

Mass spectrometry with electrospray ionization (ESI-MS) is an analytical technique used to identify and quantify chemical species in a sample based on the mass-to-charge ratio of charged particles. In ESI-MS, analytes are ionized through the use of an electrospray, where a liquid sample is introduced through a metal capillary needle at high voltage, creating an aerosol of charged droplets. As the solvent evaporates, the analyte molecules become charged and can be directed into a mass spectrometer for analysis.

ESI-MS is particularly useful for the analysis of large biomolecules such as proteins, peptides, and nucleic acids, due to its ability to gently ionize these species without fragmentation. The technique provides information about the molecular weight and charge state of the analytes, which can be used to infer their identity and structure. Additionally, ESI-MS can be interfaced with separation techniques such as liquid chromatography (LC) for further purification and characterization of complex samples.

Volatile oils, also known as essential oils, are a type of organic compound that are naturally produced in plants. They are called "volatile" because they evaporate quickly at room temperature due to their high vapor pressure. These oils are composed of complex mixtures of various compounds, including terpenes, terpenoids, aldehydes, ketones, esters, and alcohols. They are responsible for the characteristic aroma and flavor of many plants and are often used in perfumes, flavors, and aromatherapy. In a medical context, volatile oils may have therapeutic properties and be used in certain medications or treatments, but it's important to note that they can also cause adverse reactions if not used properly.

Volatilization, in the context of pharmacology and medicine, refers to the process by which a substance (usually a medication or drug) transforms into a vapor state at room temperature or upon heating. This change in physical state allows the substance to evaporate and be transferred into the air, potentially leading to inhalation exposure.

In some medical applications, volatilization is used intentionally, such as with essential oils for aromatherapy or topical treatments that utilize a vapor action. However, it can also pose concerns when volatile substances are unintentionally released into the air, potentially leading to indoor air quality issues or exposure risks.

It's important to note that in clinical settings, volatilization is not typically used as a route of administration for medications, as other methods such as oral, intravenous, or inhalation via nebulizers are more common and controlled.

'Ocimum basilicum' is the scientific name for the herb commonly known as sweet basil. While it is not a medical term itself, basil has been used in various traditional medicinal practices for its supposed benefits. However, there is limited scientific evidence to support many of these claims. It is more widely recognized as a culinary herb and essential oil source.

Thin-layer chromatography (TLC) is a type of chromatography used to separate, identify, and quantify the components of a mixture. In TLC, the sample is applied as a small spot onto a thin layer of adsorbent material, such as silica gel or alumina, which is coated on a flat, rigid support like a glass plate. The plate is then placed in a developing chamber containing a mobile phase, typically a mixture of solvents.

As the mobile phase moves up the plate by capillary action, it interacts with the stationary phase and the components of the sample. Different components of the mixture travel at different rates due to their varying interactions with the stationary and mobile phases, resulting in distinct spots on the plate. The distance each component travels can be measured and compared to known standards to identify and quantify the components of the mixture.

TLC is a simple, rapid, and cost-effective technique that is widely used in various fields, including forensics, pharmaceuticals, and research laboratories. It allows for the separation and analysis of complex mixtures with high resolution and sensitivity, making it an essential tool in many analytical applications.

Androstenediols are endogenous steroid hormones that are produced in the body from dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS), which are secreted by the adrenal glands. There are two major types of androstenediols: 5-androstenediol and 4-androstenediol. These hormones can be further metabolized into testosterone and estrogens, making them important intermediates in steroid hormone synthesis.

5-androstenediol is a weak androgen that can be converted to testosterone in peripheral tissues, while 4-androstenediol has little known biological activity. Both of these compounds have been studied for their potential role in various physiological processes, including sexual differentiation, bone metabolism, and aging. However, more research is needed to fully understand their functions and clinical significance.

It's worth noting that androstenediols are also sometimes referred to as "prohormones" because they can be converted into active steroid hormones in the body. Some athletes and bodybuilders have used synthetic forms of these compounds as performance-enhancing drugs, although their use is banned by many sports organizations due to concerns about potential health risks and unfair advantages in competition.

Acetic anhydride is a chemical compound with the formula (CH3CO)2O. It is a colorless liquid that is used as a reagent in organic synthesis, particularly in the production of cellulose acetate and other acetate esters. Acetic anhydride is also an important intermediate in the synthesis of certain pharmaceuticals and dyes.

In medical terminology, acetic anhydride is not typically used as a diagnostic or therapeutic agent. However, it can be used in laboratory settings to synthesize compounds that may have medical applications. For example, acetic anhydride has been used to produce certain antiviral drugs and antibiotics.

It is important to note that acetic anhydride can be harmful or fatal if swallowed, inhaled, or absorbed through the skin. It can cause burns and eye damage, and may be harmful to the respiratory system if inhaled. Therefore, it should be handled with care and used only in well-ventilated areas with appropriate personal protective equipment.

Substance abuse detection refers to the process of identifying the use or misuse of psychoactive substances, such as alcohol, illicit drugs, or prescription medications, in an individual. This can be done through various methods, including:

1. Physical examination: A healthcare professional may look for signs of substance abuse, such as track marks, enlarged pupils, or unusual behavior.
2. Laboratory tests: Urine, blood, hair, or saliva samples can be analyzed to detect the presence of drugs or their metabolites. These tests can provide information about recent use (hours to days) or longer-term use (up to several months).
3. Self-report measures: Individuals may be asked to complete questionnaires or interviews about their substance use patterns and behaviors.
4. Observational assessments: In some cases, such as in a treatment setting, healthcare professionals may observe an individual's behavior over time to identify patterns of substance abuse.

Substance abuse detection is often used in clinical, workplace, or legal settings to assess individuals for potential substance use disorders, monitor treatment progress, or ensure compliance with laws or regulations.

Meconium is the first stool passed by a newborn infant, typically within the first 48 hours of life. It is composed of materials ingested during fetal development, including intestinal epithelial cells, lanugo (fine hair), amniotic fluid, mucus, bile, and water. The color of meconium is usually greenish-black, and its consistency can range from a thick paste to a liquid. Meconium staining of the amniotic fluid can occur when the fetus has passed meconium while still in the uterus, which may indicate fetal distress and requires careful medical attention during delivery.

Deuterium is a stable and non-radioactive isotope of hydrogen. The atomic nucleus of deuterium, called a deuteron, contains one proton and one neutron, giving it an atomic weight of approximately 2.014 atomic mass units (amu). It is also known as heavy hydrogen or heavy water because its hydrogen atoms contain one neutron in addition to the usual one proton found in common hydrogen atoms.

Deuterium occurs naturally in trace amounts in water and other organic compounds, typically making up about 0.015% to 0.018% of all hydrogen atoms. It can be separated from regular hydrogen through various methods such as electrolysis or distillation, and it has many applications in scientific research, particularly in the fields of chemistry and physics.

In medical contexts, deuterium is sometimes used as a tracer to study metabolic processes in the body. By replacing hydrogen atoms in specific molecules with deuterium atoms, researchers can track the movement and transformation of those molecules within living organisms. This technique has been used to investigate various physiological processes, including drug metabolism, energy production, and lipid synthesis.

Doping in sports is the use of prohibited substances or methods to improve athletic performance. The World Anti-Doping Agency (WADA) defines doping as "the occurrence of one or more of the following anti-doping rule violations":

1. Presence of a prohibited substance in an athlete's sample
2. Use or attempted use of a prohibited substance or method
3. Evading, refusing, or failing to submit to sample collection
4. Whereabouts failures (three missed tests or filing failures within a 12-month period)
5. Tampering or attempted tampering with any part of the doping control process
6. Possession, trafficking, or administration of a prohibited substance or method
7. Complicity in an anti-doping rule violation
8. Prohibited association with a person who has been serving a period of ineligibility for an anti-doping rule violation

Doping is considered unethical and harmful to the integrity of sports, as it provides an unfair advantage to those who engage in it. It can also have serious health consequences for athletes. Various international and national organizations, including WADA and the United States Anti-Doping Agency (USADA), work to prevent doping in sports through education, testing, and enforcement of anti-doping rules.

F2-isoprostanes are a type of prostaglandin-like compound that is formed in the body through the free radical-catalyzed peroxidation of arachidonic acid, a polyunsaturated fatty acid found in cell membranes. They are produced in response to oxidative stress and are often used as a biomarker for lipid peroxidation and oxidative damage in various diseases, including atherosclerosis, cancer, and neurodegenerative disorders. F2-isoprostanes are chemically stable and can be measured in biological fluids such as blood, urine, and breath condensate. They have been shown to cause vasoconstriction, platelet aggregation, and inflammation, which may contribute to the pathogenesis of various diseases.

Magnetic Resonance Spectroscopy (MRS) is a non-invasive diagnostic technique that provides information about the biochemical composition of tissues, including their metabolic state. It is often used in conjunction with Magnetic Resonance Imaging (MRI) to analyze various metabolites within body tissues, such as the brain, heart, liver, and muscles.

During MRS, a strong magnetic field, radio waves, and a computer are used to produce detailed images and data about the concentration of specific metabolites in the targeted tissue or organ. This technique can help detect abnormalities related to energy metabolism, neurotransmitter levels, pH balance, and other biochemical processes, which can be useful for diagnosing and monitoring various medical conditions, including cancer, neurological disorders, and metabolic diseases.

There are different types of MRS, such as Proton (^1^H) MRS, Phosphorus-31 (^31^P) MRS, and Carbon-13 (^13^C) MRS, each focusing on specific elements or metabolites within the body. The choice of MRS technique depends on the clinical question being addressed and the type of information needed for diagnosis or monitoring purposes.

Fatty acids are carboxylic acids with a long aliphatic chain, which are important components of lipids and are widely distributed in living organisms. They can be classified based on the length of their carbon chain, saturation level (presence or absence of double bonds), and other structural features.

The two main types of fatty acids are:

1. Saturated fatty acids: These have no double bonds in their carbon chain and are typically solid at room temperature. Examples include palmitic acid (C16:0) and stearic acid (C18:0).
2. Unsaturated fatty acids: These contain one or more double bonds in their carbon chain and can be further classified into monounsaturated (one double bond) and polyunsaturated (two or more double bonds) fatty acids. Examples of unsaturated fatty acids include oleic acid (C18:1, monounsaturated), linoleic acid (C18:2, polyunsaturated), and alpha-linolenic acid (C18:3, polyunsaturated).

Fatty acids play crucial roles in various biological processes, such as energy storage, membrane structure, and cell signaling. Some essential fatty acids cannot be synthesized by the human body and must be obtained through dietary sources.

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a type of mass spectrometry that is used to analyze large biomolecules such as proteins and peptides. In this technique, the sample is mixed with a matrix compound, which absorbs laser energy and helps to vaporize and ionize the analyte molecules.

The matrix-analyte mixture is then placed on a target plate and hit with a laser beam, causing the matrix and analyte molecules to desorb from the plate and become ionized. The ions are then accelerated through an electric field and into a mass analyzer, which separates them based on their mass-to-charge ratio.

The separated ions are then detected and recorded as a mass spectrum, which can be used to identify and quantify the analyte molecules present in the sample. MALDI-MS is particularly useful for the analysis of complex biological samples, such as tissue extracts or biological fluids, because it allows for the detection and identification of individual components within those mixtures.

Biotransformation is the metabolic modification of a chemical compound, typically a xenobiotic (a foreign chemical substance found within an living organism), by a biological system. This process often involves enzymatic conversion of the parent compound to one or more metabolites, which may be more or less active, toxic, or mutagenic than the original substance.

In the context of pharmacology and toxicology, biotransformation is an important aspect of drug metabolism and elimination from the body. The liver is the primary site of biotransformation, but other organs such as the kidneys, lungs, and gastrointestinal tract can also play a role.

Biotransformation can occur in two phases: phase I reactions involve functionalization of the parent compound through oxidation, reduction, or hydrolysis, while phase II reactions involve conjugation of the metabolite with endogenous molecules such as glucuronic acid, sulfate, or acetate to increase its water solubility and facilitate excretion.

Carboxylic acids are organic compounds that contain a carboxyl group, which is a functional group made up of a carbon atom doubly bonded to an oxygen atom and single bonded to a hydroxyl group. The general formula for a carboxylic acid is R-COOH, where R represents the rest of the molecule.

Carboxylic acids can be found in various natural sources such as in fruits, vegetables, and animal products. Some common examples of carboxylic acids include formic acid (HCOOH), acetic acid (CH3COOH), propionic acid (C2H5COOH), and butyric acid (C3H7COOH).

Carboxylic acids have a variety of uses in industry, including as food additives, pharmaceuticals, and industrial chemicals. They are also important intermediates in the synthesis of other organic compounds. In the body, carboxylic acids play important roles in metabolism and energy production.

Hydroxyeicosatetraenoic acids (HETEs) are a type of metabolite produced by the oxidation of arachidonic acid, a polyunsaturated fatty acid that is found in the membranes of cells in the human body. This oxidation process is catalyzed by enzymes called lipoxygenases (LOXs) and cytochrome P450 monooxygenases (CYP450).

HETEs are biologically active compounds that play a role in various physiological and pathophysiological processes, including inflammation, immune response, and cancer. They can act as signaling molecules, modulating the activity of various cell types, such as leukocytes, endothelial cells, and smooth muscle cells.

There are several different types of HETEs, depending on the position of the hydroxyl group (-OH) attached to the arachidonic acid molecule. For example, 5-HETE, 12-HETE, and 15-HETE are produced by 5-LOX, 12-LOX, and 15-LOX, respectively, while CYP450 can produce 20-HETE.

It's worth noting that HETEs have been implicated in various diseases, such as atherosclerosis, hypertension, and cancer, making them potential targets for therapeutic intervention. However, further research is needed to fully understand their roles and develop effective treatments.

In medical terms, gases refer to the state of matter that has no fixed shape or volume and expands to fill any container it is placed in. Gases in the body can be normal, such as the oxygen, carbon dioxide, and nitrogen that are present in the lungs and blood, or abnormal, such as gas that accumulates in the digestive tract due to conditions like bloating or swallowing air.

Gases can also be used medically for therapeutic purposes, such as in the administration of anesthesia or in the treatment of certain respiratory conditions with oxygen therapy. Additionally, measuring the amount of gas in the body, such as through imaging studies like X-rays or CT scans, can help diagnose various medical conditions.

Urinalysis is a medical examination and analysis of urine. It's used to detect and manage a wide range of disorders, such as diabetes, kidney disease, and liver problems. A urinalysis can also help monitor medications and drug compliance. The test typically involves checking the color, clarity, and specific gravity (concentration) of urine. It may also include chemical analysis to detect substances like glucose, protein, blood, and white blood cells, which could indicate various medical conditions. In some cases, a microscopic examination is performed to identify any abnormal cells, casts, or crystals present in the urine.

Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.

In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.

The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Esters are organic compounds that are formed by the reaction between an alcohol and a carboxylic acid. They are widely found in nature and are used in various industries, including the production of perfumes, flavors, and pharmaceuticals. In the context of medical definitions, esters may be mentioned in relation to their use as excipients in medications or in discussions of organic chemistry and biochemistry. Esters can also be found in various natural substances such as fats and oils, which are triesters of glycerol and fatty acids.

"Quality control" is a term that is used in many industries, including healthcare and medicine, to describe the systematic process of ensuring that products or services meet certain standards and regulations. In the context of healthcare, quality control often refers to the measures taken to ensure that the care provided to patients is safe, effective, and consistent. This can include processes such as:

1. Implementing standardized protocols and guidelines for care
2. Training and educating staff to follow these protocols
3. Regularly monitoring and evaluating the outcomes of care
4. Making improvements to processes and systems based on data and feedback
5. Ensuring that equipment and supplies are maintained and functioning properly
6. Implementing systems for reporting and addressing safety concerns or errors.

The goal of quality control in healthcare is to provide high-quality, patient-centered care that meets the needs and expectations of patients, while also protecting their safety and well-being.

Steroids, also known as corticosteroids, are a type of hormone that the adrenal gland produces in your body. They have many functions, such as controlling the balance of salt and water in your body and helping to reduce inflammation. Steroids can also be synthetically produced and used as medications to treat a variety of conditions, including allergies, asthma, skin conditions, and autoimmune disorders.

Steroid medications are available in various forms, such as oral pills, injections, creams, and inhalers. They work by mimicking the effects of natural hormones produced by your body, reducing inflammation and suppressing the immune system's response to prevent or reduce symptoms. However, long-term use of steroids can have significant side effects, including weight gain, high blood pressure, osteoporosis, and increased risk of infections.

It is important to note that anabolic steroids are a different class of drugs that are sometimes abused for their muscle-building properties. These steroids are synthetic versions of the male hormone testosterone and can have serious health consequences when taken in large doses or without medical supervision.

Methylation, in the context of genetics and epigenetics, refers to the addition of a methyl group (CH3) to a molecule, usually to the nitrogenous base of DNA or to the side chain of amino acids in proteins. In DNA methylation, this process typically occurs at the 5-carbon position of cytosine residues that precede guanine residues (CpG sites) and is catalyzed by enzymes called DNA methyltransferases (DNMTs).

DNA methylation plays a crucial role in regulating gene expression, genomic imprinting, X-chromosome inactivation, and suppression of repetitive elements. Hypermethylation or hypomethylation of specific genes can lead to altered gene expression patterns, which have been associated with various human diseases, including cancer.

In summary, methylation is a fundamental epigenetic modification that influences genomic stability, gene regulation, and cellular function by introducing methyl groups to DNA or proteins.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

Carbohydrate conformation refers to the three-dimensional shape and structure of a carbohydrate molecule. Carbohydrates, also known as sugars, can exist in various conformational states, which are determined by the rotation of their component bonds and the spatial arrangement of their functional groups.

The conformation of a carbohydrate molecule can have significant implications for its biological activity and recognition by other molecules, such as enzymes or antibodies. Factors that can influence carbohydrate conformation include the presence of intramolecular hydrogen bonds, steric effects, and intermolecular interactions with solvent molecules or other solutes.

In some cases, the conformation of a carbohydrate may be stabilized by the formation of cyclic structures, in which the hydroxyl group at one end of the molecule forms a covalent bond with the carbonyl carbon at the other end, creating a ring structure. The most common cyclic carbohydrates are monosaccharides, such as glucose and fructose, which can exist in various conformational isomers known as anomers.

Understanding the conformation of carbohydrate molecules is important for elucidating their biological functions and developing strategies for targeting them with drugs or other therapeutic agents.

Chemical water pollutants refer to harmful chemicals or substances that contaminate bodies of water, making them unsafe for human use and harmful to aquatic life. These pollutants can come from various sources, including industrial and agricultural runoff, sewage and wastewater, oil spills, and improper disposal of hazardous materials.

Examples of chemical water pollutants include heavy metals (such as lead, mercury, and cadmium), pesticides and herbicides, volatile organic compounds (VOCs), polychlorinated biphenyls (PCBs), and petroleum products. These chemicals can have toxic effects on aquatic organisms, disrupt ecosystems, and pose risks to human health through exposure or consumption.

Regulations and standards are in place to monitor and limit the levels of chemical pollutants in water sources, with the aim of protecting public health and the environment.

A "carbohydrate sequence" refers to the specific arrangement or order of monosaccharides (simple sugars) that make up a carbohydrate molecule, such as a polysaccharide or an oligosaccharide. Carbohydrates are often composed of repeating units of monosaccharides, and the sequence in which these units are arranged can have important implications for the function and properties of the carbohydrate.

For example, in glycoproteins (proteins that contain carbohydrate chains), the specific carbohydrate sequence can affect how the protein is processed and targeted within the cell, as well as its stability and activity. Similarly, in complex carbohydrates like starch or cellulose, the sequence of glucose units can determine whether the molecule is branched or unbranched, which can have implications for its digestibility and other properties.

Therefore, understanding the carbohydrate sequence is an important aspect of studying carbohydrate structure and function in biology and medicine.

Lipoxygenase is an enzyme that catalyzes the dioxygenation of polyunsaturated fatty acids containing a cis,cis-1,4-pentadiene structure, forming hydroperoxides. This reaction is important in the biosynthesis of leukotrienes and lipoxins, which are involved in various inflammatory responses and immune functions. There are several isoforms of lipoxygenase found in different tissues and organisms, including arachidonate 5-lipoxygenase, arachidonate 12-lipoxygenase, and arachidonate 15-lipoxygenase.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds characterized by the presence of two or more fused benzene rings. They are called "polycyclic" because they contain multiple cyclic structures, and "aromatic" because these structures contain alternating double bonds that give them distinctive chemical properties and a characteristic smell.

PAHs can be produced from both natural and anthropogenic sources. Natural sources include wildfires, volcanic eruptions, and the decomposition of organic matter. Anthropogenic sources include the incomplete combustion of fossil fuels, such as coal, oil, and gasoline, as well as tobacco smoke, grilled foods, and certain industrial processes.

PAHs are known to be environmental pollutants and can have harmful effects on human health. They have been linked to an increased risk of cancer, particularly lung, skin, and bladder cancers, as well as reproductive and developmental toxicity. PAHs can also cause skin irritation, respiratory problems, and damage to the immune system.

PAHs are found in a variety of environmental media, including air, water, soil, and food. They can accumulate in the food chain, particularly in fatty tissues, and have been detected in a wide range of foods, including meat, fish, dairy products, and vegetables. Exposure to PAHs can occur through inhalation, ingestion, or skin contact.

It is important to limit exposure to PAHs by avoiding tobacco smoke, reducing consumption of grilled and smoked foods, using ventilation when cooking, and following safety guidelines when working with industrial processes that produce PAHs.

Stereoisomerism is a type of isomerism (structural arrangement of atoms) in which molecules have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientation of their atoms in space. This occurs when the molecule contains asymmetric carbon atoms or other rigid structures that prevent free rotation, leading to distinct spatial arrangements of groups of atoms around a central point. Stereoisomers can have different chemical and physical properties, such as optical activity, boiling points, and reactivities, due to differences in their shape and the way they interact with other molecules.

There are two main types of stereoisomerism: enantiomers (mirror-image isomers) and diastereomers (non-mirror-image isomers). Enantiomers are pairs of stereoisomers that are mirror images of each other, but cannot be superimposed on one another. Diastereomers, on the other hand, are non-mirror-image stereoisomers that have different physical and chemical properties.

Stereoisomerism is an important concept in chemistry and biology, as it can affect the biological activity of molecules, such as drugs and natural products. For example, some enantiomers of a drug may be active, while others are inactive or even toxic. Therefore, understanding stereoisomerism is crucial for designing and synthesizing effective and safe drugs.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

In the context of medicine, "chemistry" often refers to the field of study concerned with the properties, composition, and structure of elements and compounds, as well as their reactions with one another. It is a fundamental science that underlies much of modern medicine, including pharmacology (the study of drugs), toxicology (the study of poisons), and biochemistry (the study of the chemical processes that occur within living organisms).

In addition to its role as a basic science, chemistry is also used in medical testing and diagnosis. For example, clinical chemistry involves the analysis of bodily fluids such as blood and urine to detect and measure various substances, such as glucose, cholesterol, and electrolytes, that can provide important information about a person's health status.

Overall, chemistry plays a critical role in understanding the mechanisms of diseases, developing new treatments, and improving diagnostic tests and techniques.

Chemical phenomena refer to the changes and interactions that occur at the molecular or atomic level when chemicals are involved. These phenomena can include chemical reactions, in which one or more substances (reactants) are converted into different substances (products), as well as physical properties that change as a result of chemical interactions, such as color, state of matter, and solubility. Chemical phenomena can be studied through various scientific disciplines, including chemistry, biochemistry, and physics.

Arachidonic acids are a type of polyunsaturated fatty acid that is primarily found in the phospholipids of cell membranes. They contain 20 carbon atoms and four double bonds (20:4n-6), with the first double bond located at the sixth carbon atom from the methyl end.

Arachidonic acids are derived from linoleic acid, an essential fatty acid that cannot be synthesized by the human body and must be obtained through dietary sources such as meat, fish, and eggs. Once ingested, linoleic acid is converted to arachidonic acid in a series of enzymatic reactions.

Arachidonic acids play an important role in various physiological processes, including inflammation, immune response, and cell signaling. They serve as precursors for the synthesis of eicosanoids, which are signaling molecules that include prostaglandins, thromboxanes, and leukotrienes. These eicosanoids have diverse biological activities, such as modulating blood flow, platelet aggregation, and pain perception, among others.

However, excessive production of arachidonic acid-derived eicosanoids has been implicated in various pathological conditions, including inflammation, atherosclerosis, and cancer. Therefore, the regulation of arachidonic acid metabolism is an important area of research for the development of new therapeutic strategies.

Arachidonic acid is a type of polyunsaturated fatty acid that is found naturally in the body and in certain foods. It is an essential fatty acid, meaning that it cannot be produced by the human body and must be obtained through the diet. Arachidonic acid is a key component of cell membranes and plays a role in various physiological processes, including inflammation and blood clotting.

In the body, arachidonic acid is released from cell membranes in response to various stimuli, such as injury or infection. Once released, it can be converted into a variety of bioactive compounds, including prostaglandins, thromboxanes, and leukotrienes, which mediate various physiological responses, including inflammation, pain, fever, and blood clotting.

Arachidonic acid is found in high concentrations in animal products such as meat, poultry, fish, and eggs, as well as in some plant sources such as certain nuts and seeds. It is also available as a dietary supplement. However, it is important to note that excessive intake of arachidonic acid can contribute to the development of inflammation and other health problems, so it is recommended to consume this fatty acid in moderation as part of a balanced diet.

Hydrolysis is a chemical process, not a medical one. However, it is relevant to medicine and biology.

Hydrolysis is the breakdown of a chemical compound due to its reaction with water, often resulting in the formation of two or more simpler compounds. In the context of physiology and medicine, hydrolysis is a crucial process in various biological reactions, such as the digestion of food molecules like proteins, carbohydrates, and fats. Enzymes called hydrolases catalyze these hydrolysis reactions to speed up the breakdown process in the body.

Proteomics is the large-scale study and analysis of proteins, including their structures, functions, interactions, modifications, and abundance, in a given cell, tissue, or organism. It involves the identification and quantification of all expressed proteins in a biological sample, as well as the characterization of post-translational modifications, protein-protein interactions, and functional pathways. Proteomics can provide valuable insights into various biological processes, diseases, and drug responses, and has applications in basic research, biomedicine, and clinical diagnostics. The field combines various techniques from molecular biology, chemistry, physics, and bioinformatics to study proteins at a systems level.

Dinoprost is a synthetic form of prostaglandin F2α, which is a naturally occurring hormone-like substance in the body. It is used in veterinary medicine as a uterotonic agent to induce labor and abortion in various animals such as cows and pigs. In human medicine, it may be used off-label for similar purposes, but its use must be under the close supervision of a healthcare provider due to potential side effects and risks.

It is important to note that Dinoprost is not approved by the FDA for use in humans, and its availability may vary depending on the country or region. Always consult with a licensed healthcare professional before using any medication, including Dinoprost.

The Cytochrome P-450 (CYP450) enzyme system is a group of enzymes found primarily in the liver, but also in other organs such as the intestines, lungs, and skin. These enzymes play a crucial role in the metabolism and biotransformation of various substances, including drugs, environmental toxins, and endogenous compounds like hormones and fatty acids.

The name "Cytochrome P-450" refers to the unique property of these enzymes to bind to carbon monoxide (CO) and form a complex that absorbs light at a wavelength of 450 nm, which can be detected spectrophotometrically.

The CYP450 enzyme system is involved in Phase I metabolism of xenobiotics, where it catalyzes oxidation reactions such as hydroxylation, dealkylation, and epoxidation. These reactions introduce functional groups into the substrate molecule, which can then undergo further modifications by other enzymes during Phase II metabolism.

There are several families and subfamilies of CYP450 enzymes, each with distinct substrate specificities and functions. Some of the most important CYP450 enzymes include:

1. CYP3A4: This is the most abundant CYP450 enzyme in the human liver and is involved in the metabolism of approximately 50% of all drugs. It also metabolizes various endogenous compounds like steroids, bile acids, and vitamin D.
2. CYP2D6: This enzyme is responsible for the metabolism of many psychotropic drugs, including antidepressants, antipsychotics, and beta-blockers. It also metabolizes some endogenous compounds like dopamine and serotonin.
3. CYP2C9: This enzyme plays a significant role in the metabolism of warfarin, phenytoin, and nonsteroidal anti-inflammatory drugs (NSAIDs).
4. CYP2C19: This enzyme is involved in the metabolism of proton pump inhibitors, antidepressants, and clopidogrel.
5. CYP2E1: This enzyme metabolizes various xenobiotics like alcohol, acetaminophen, and carbon tetrachloride, as well as some endogenous compounds like fatty acids and prostaglandins.

Genetic polymorphisms in CYP450 enzymes can significantly affect drug metabolism and response, leading to interindividual variability in drug efficacy and toxicity. Understanding the role of CYP450 enzymes in drug metabolism is crucial for optimizing pharmacotherapy and minimizing adverse effects.

Unsaturated fatty acids are a type of fatty acid that contain one or more double bonds in their carbon chain. These double bonds can be either cis or trans configurations, although the cis configuration is more common in nature. The presence of these double bonds makes unsaturated fatty acids more liquid at room temperature and less prone to spoilage than saturated fatty acids, which do not have any double bonds.

Unsaturated fatty acids can be further classified into two main categories: monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). MUFAs contain one double bond in their carbon chain, while PUFAs contain two or more.

Examples of unsaturated fatty acids include oleic acid (a MUFA found in olive oil), linoleic acid (a PUFA found in vegetable oils), and alpha-linolenic acid (an omega-3 PUFA found in flaxseed and fish). Unsaturated fatty acids are essential nutrients for the human body, as they play important roles in various physiological processes such as membrane structure, inflammation, and blood clotting. It is recommended to consume a balanced diet that includes both MUFAs and PUFAs to maintain good health.

A biological marker, often referred to as a biomarker, is a measurable indicator that reflects the presence or severity of a disease state, or a response to a therapeutic intervention. Biomarkers can be found in various materials such as blood, tissues, or bodily fluids, and they can take many forms, including molecular, histologic, radiographic, or physiological measurements.

In the context of medical research and clinical practice, biomarkers are used for a variety of purposes, such as:

1. Diagnosis: Biomarkers can help diagnose a disease by indicating the presence or absence of a particular condition. For example, prostate-specific antigen (PSA) is a biomarker used to detect prostate cancer.
2. Monitoring: Biomarkers can be used to monitor the progression or regression of a disease over time. For instance, hemoglobin A1c (HbA1c) levels are monitored in diabetes patients to assess long-term blood glucose control.
3. Predicting: Biomarkers can help predict the likelihood of developing a particular disease or the risk of a negative outcome. For example, the presence of certain genetic mutations can indicate an increased risk for breast cancer.
4. Response to treatment: Biomarkers can be used to evaluate the effectiveness of a specific treatment by measuring changes in the biomarker levels before and after the intervention. This is particularly useful in personalized medicine, where treatments are tailored to individual patients based on their unique biomarker profiles.

It's important to note that for a biomarker to be considered clinically valid and useful, it must undergo rigorous validation through well-designed studies, including demonstrating sensitivity, specificity, reproducibility, and clinical relevance.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

Heptanes are a group of hydrocarbons that are composed of straight-chain or branched arrangements of six carbon atoms and are commonly found in gasoline. They are colorless liquids at room temperature with a characteristic odor. In a medical context, exposure to heptanes can occur through inhalation, skin contact, or ingestion, and can cause symptoms such as headache, dizziness, nausea, and irritation of the eyes, nose, and throat. Chronic exposure has been linked to more serious health effects, including neurological damage and cancer. Proper handling and use of heptanes, as well as adequate ventilation, are important to minimize exposure and potential health risks.

Affinity chromatography is a type of chromatography technique used in biochemistry and molecular biology to separate and purify proteins based on their biological characteristics, such as their ability to bind specifically to certain ligands or molecules. This method utilizes a stationary phase that is coated with a specific ligand (e.g., an antibody, antigen, receptor, or enzyme) that selectively interacts with the target protein in a sample.

The process typically involves the following steps:

1. Preparation of the affinity chromatography column: The stationary phase, usually a solid matrix such as agarose beads or magnetic beads, is modified by covalently attaching the ligand to its surface.
2. Application of the sample: The protein mixture is applied to the top of the affinity chromatography column, allowing it to flow through the stationary phase under gravity or pressure.
3. Binding and washing: As the sample flows through the column, the target protein selectively binds to the ligand on the stationary phase, while other proteins and impurities pass through. The column is then washed with a suitable buffer to remove any unbound proteins and contaminants.
4. Elution of the bound protein: The target protein can be eluted from the column using various methods, such as changing the pH, ionic strength, or polarity of the buffer, or by introducing a competitive ligand that displaces the bound protein.
5. Collection and analysis: The eluted protein fraction is collected and analyzed for purity and identity, often through techniques like SDS-PAGE or mass spectrometry.

Affinity chromatography is a powerful tool in biochemistry and molecular biology due to its high selectivity and specificity, enabling the efficient isolation of target proteins from complex mixtures. However, it requires careful consideration of the binding affinity between the ligand and the protein, as well as optimization of the elution conditions to minimize potential damage or denaturation of the purified protein.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Ion exchange chromatography is a type of chromatography technique used to separate and analyze charged molecules (ions) based on their ability to exchange bound ions in a solid resin or gel with ions of similar charge in the mobile phase. The stationary phase, often called an ion exchanger, contains fixed ated functional groups that can attract counter-ions of opposite charge from the sample mixture.

In this technique, the sample is loaded onto an ion exchange column containing the charged resin or gel. As the sample moves through the column, ions in the sample compete for binding sites on the stationary phase with ions already present in the column. The ions that bind most strongly to the stationary phase will elute (come off) slower than those that bind more weakly.

Ion exchange chromatography can be performed using either cation exchangers, which exchange positive ions (cations), or anion exchangers, which exchange negative ions (anions). The pH and ionic strength of the mobile phase can be adjusted to control the binding and elution of specific ions.

Ion exchange chromatography is widely used in various applications such as water treatment, protein purification, and chemical analysis.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Eucommiaceae is a family of flowering plants that includes only one extant genus, Eucommia, which contains a single species, Eucommia ulmoides. This plant, also known as the "hardy rubber tree" or "gutta-percha tree," is native to China and is known for producing a latex sap that can be used to make rubber.

Eucommia ulmoides has been used in traditional Chinese medicine for centuries, and recent research has suggested that it may have various medicinal properties, including anti-inflammatory, antioxidant, and immune-boosting effects. However, more research is needed to confirm these potential benefits and to determine the safety and efficacy of Eucommia ulmoides as a medical treatment.

In the context of medicine and medical devices, calibration refers to the process of checking, adjusting, or confirming the accuracy of a measurement instrument or system. This is typically done by comparing the measurements taken by the device being calibrated to those taken by a reference standard of known accuracy. The goal of calibration is to ensure that the medical device is providing accurate and reliable measurements, which is critical for making proper diagnoses and delivering effective treatment. Regular calibration is an important part of quality assurance and helps to maintain the overall performance and safety of medical devices.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Lipid metabolism is the process by which the body breaks down and utilizes lipids (fats) for various functions, such as energy production, cell membrane formation, and hormone synthesis. This complex process involves several enzymes and pathways that regulate the digestion, absorption, transport, storage, and consumption of fats in the body.

The main types of lipids involved in metabolism include triglycerides, cholesterol, phospholipids, and fatty acids. The breakdown of these lipids begins in the digestive system, where enzymes called lipases break down dietary fats into smaller molecules called fatty acids and glycerol. These molecules are then absorbed into the bloodstream and transported to the liver, which is the main site of lipid metabolism.

In the liver, fatty acids may be further broken down for energy production or used to synthesize new lipids. Excess fatty acids may be stored as triglycerides in specialized cells called adipocytes (fat cells) for later use. Cholesterol is also metabolized in the liver, where it may be used to synthesize bile acids, steroid hormones, and other important molecules.

Disorders of lipid metabolism can lead to a range of health problems, including obesity, diabetes, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD). These conditions may be caused by genetic factors, lifestyle habits, or a combination of both. Proper diagnosis and management of lipid metabolism disorders typically involves a combination of dietary changes, exercise, and medication.

Isotope labeling is a scientific technique used in the field of medicine, particularly in molecular biology, chemistry, and pharmacology. It involves replacing one or more atoms in a molecule with a radioactive or stable isotope of the same element. This modified molecule can then be traced and analyzed to study its structure, function, metabolism, or interaction with other molecules within biological systems.

Radioisotope labeling uses unstable radioactive isotopes that emit radiation, allowing for detection and quantification of the labeled molecule using various imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT). This approach is particularly useful in tracking the distribution and metabolism of drugs, hormones, or other biomolecules in living organisms.

Stable isotope labeling, on the other hand, employs non-radioactive isotopes that do not emit radiation. These isotopes have different atomic masses compared to their natural counterparts and can be detected using mass spectrometry. Stable isotope labeling is often used in metabolic studies, protein turnover analysis, or for identifying the origin of specific molecules within complex biological samples.

In summary, isotope labeling is a versatile tool in medical research that enables researchers to investigate various aspects of molecular behavior and interactions within biological systems.

I'm sorry for any confusion, but "Pentanes" is not a medical term. It is a chemical term that refers to a group of five-carbon alkane hydrocarbons, including n-pentane and iso-pentane. These substances can be used in medical settings as anesthetics or for medical research, but "Pentanes" itself does not have a specific medical definition.

Chromatography is a technique used in analytical chemistry for the separation, identification, and quantification of the components of a mixture. It is based on the differential distribution of the components of a mixture between a stationary phase and a mobile phase. The stationary phase can be a solid or liquid, while the mobile phase is a gas, liquid, or supercritical fluid that moves through the stationary phase carrying the sample components.

The interaction between the sample components and the stationary and mobile phases determines how quickly each component will move through the system. Components that interact more strongly with the stationary phase will move more slowly than those that interact more strongly with the mobile phase. This difference in migration rates allows for the separation of the components, which can then be detected and quantified.

There are many different types of chromatography, including paper chromatography, thin-layer chromatography (TLC), gas chromatography (GC), liquid chromatography (LC), and high-performance liquid chromatography (HPLC). Each type has its own strengths and weaknesses, and is best suited for specific applications.

In summary, chromatography is a powerful analytical technique used to separate, identify, and quantify the components of a mixture based on their differential distribution between a stationary phase and a mobile phase.

8,11,14-Eicosatrienoic acid is a type of fatty acid that contains 20 carbon atoms and three double bonds. The locations of these double bonds are at the 8th, 11th, and 14th carbon atoms, hence the name of the fatty acid. It is an omega-3 fatty acid, which means that the first double bond is located between the third and fourth carbon atoms from the methyl end of the molecule.

This particular fatty acid is not considered to be essential for human health, as it can be synthesized in the body from other fatty acids. It is a component of certain types of lipids found in animal tissues, including beef and lamb. It has been studied for its potential role in various physiological processes, such as inflammation and immune function, but its specific functions and effects on human health are not well understood.

Reference standards in a medical context refer to the established and widely accepted norms or benchmarks used to compare, evaluate, or measure the performance, accuracy, or effectiveness of diagnostic tests, treatments, or procedures. These standards are often based on extensive research, clinical trials, and expert consensus, and they help ensure that healthcare practices meet certain quality and safety thresholds.

For example, in laboratory medicine, reference standards may consist of well-characterized samples with known concentrations of analytes (such as chemicals or biological markers) that are used to calibrate instruments and validate testing methods. In clinical practice, reference standards may take the form of evidence-based guidelines or best practices that define appropriate care for specific conditions or patient populations.

By adhering to these reference standards, healthcare professionals can help minimize variability in test results, reduce errors, improve diagnostic accuracy, and ensure that patients receive consistent, high-quality care.

The proteome is the entire set of proteins produced or present in an organism, system, organ, or cell at a certain time under specific conditions. It is a dynamic collection of protein species that changes over time, responding to various internal and external stimuli such as disease, stress, or environmental factors. The study of the proteome, known as proteomics, involves the identification and quantification of these protein components and their post-translational modifications, providing valuable insights into biological processes, functional pathways, and disease mechanisms.

The 'Limit of Detection' (LOD) is a term used in laboratory medicine and clinical chemistry to describe the lowest concentration or quantity of an analyte (the substance being measured) that can be reliably distinguished from zero or blank value, with a specified level of confidence. It is typically expressed as a concentration or amount and represents the minimum amount of analyte that must be present in a sample for the assay to produce a response that is statistically different from a blank or zero calibrator.

The LOD is an important parameter in analytical method validation, as it helps to define the range of concentrations over which the assay can accurately and precisely measure the analyte. It is determined based on statistical analysis of the data generated during method development and validation, taking into account factors such as the variability of the assay and the signal-to-noise ratio.

It's important to note that LOD should not be confused with the 'Limit of Quantification' (LOQ), which is the lowest concentration or quantity of an analyte that can be measured with acceptable precision and accuracy. LOQ is typically higher than LOD, as it requires a greater level of confidence in the measurement.

Gel chromatography is a type of liquid chromatography that separates molecules based on their size or molecular weight. It uses a stationary phase that consists of a gel matrix made up of cross-linked polymers, such as dextran, agarose, or polyacrylamide. The gel matrix contains pores of various sizes, which allow smaller molecules to penetrate deeper into the matrix while larger molecules are excluded.

In gel chromatography, a mixture of molecules is loaded onto the top of the gel column and eluted with a solvent that moves down the column by gravity or pressure. As the sample components move down the column, they interact with the gel matrix and get separated based on their size. Smaller molecules can enter the pores of the gel and take longer to elute, while larger molecules are excluded from the pores and elute more quickly.

Gel chromatography is commonly used to separate and purify proteins, nucleic acids, and other biomolecules based on their size and molecular weight. It is also used in the analysis of polymers, colloids, and other materials with a wide range of applications in chemistry, biology, and medicine.

Rhodiola (Rhodiola rosea), also known as golden root or roseroot, is an herb that grows in the wild Arctic regions of Europe and Asia. It has been used in traditional medicine in Russia and Scandinavia for centuries to increase stamina, strength, and mental capacity, and to help cope with cold climates and high altitudes.

Rhodiola rosea contains several chemical compounds, including rosavins and salidroside, which are believed to have adaptogenic properties, meaning they may help the body better respond to physical, chemical, and environmental stress. Some studies suggest that rhodiola may help reduce fatigue, improve mental performance, and boost the immune system, but more research is needed to confirm these effects and determine optimal dosages.

It's important to note that while some supplements containing rhodiola rosea are available over-the-counter, they are not regulated by the Food and Drug Administration (FDA) in the same way as prescription drugs, so it's important to talk to a healthcare provider before taking them. Additionally, rhodiola may interact with certain medications or have side effects, so it's important to use it under the guidance of a healthcare professional.

A breath test is a medical or forensic procedure used to analyze a sample of exhaled breath in order to detect and measure the presence of various substances, most commonly alcohol. The test is typically conducted using a device called a breathalyzer, which measures the amount of alcohol in the breath and converts it into a reading of blood alcohol concentration (BAC).

In addition to alcohol, breath tests can also be used to detect other substances such as drugs or volatile organic compounds (VOCs) that may indicate certain medical conditions. However, these types of breath tests are less common and may not be as reliable or accurate as other diagnostic tests.

Breath testing is commonly used by law enforcement officers to determine whether a driver is impaired by alcohol and to establish probable cause for arrest. It is also used in some healthcare settings to monitor patients who are being treated for alcohol abuse or dependence.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

Water pollutants refer to any substances or materials that contaminate water sources and make them unsafe or unsuitable for use. These pollutants can include a wide range of chemicals, microorganisms, and physical particles that can have harmful effects on human health, aquatic life, and the environment as a whole. Examples of water pollutants include heavy metals like lead and mercury, industrial chemicals such as polychlorinated biphenyls (PCBs) and dioxins, agricultural runoff containing pesticides and fertilizers, sewage and wastewater, oil spills, and microplastics. Exposure to water pollutants can cause a variety of health problems, ranging from minor irritations to serious illnesses or even death in extreme cases. Additionally, water pollution can have significant impacts on the environment, including harming or killing aquatic life, disrupting ecosystems, and reducing biodiversity.

Flame Ionization is not a medical term, but rather a scientific technique used in analytical chemistry to detect and measure the presence of certain organic compounds. It is based on the principle that when an organic compound is introduced into a flame, it breaks down into ions and electrons, creating an electrical current that can be measured. This technique is often used in gas chromatography to identify and quantify volatile organic compounds (VOCs) in biological samples such as breath, blood, or urine. However, it is not typically used as a diagnostic tool in medicine.

Sugar acids are a type of organic acid that are derived from sugars through the process of hydrolysis or oxidation. They have complex structures and can be found in various natural sources such as fruits, vegetables, and honey. In the medical field, sugar acids may be used in the production of pharmaceuticals and other chemical products.

Some common examples of sugar acids include:

* Gluconic acid, which is derived from glucose and has applications in the food industry as a preservative and stabilizer.
* Lactic acid, which is produced by fermentation of carbohydrates and is used in the production of various pharmaceuticals, foods, and cosmetics.
* Citric acid, which is found in citrus fruits and is widely used as a flavoring agent, preservative, and chelating agent in food, beverages, and personal care products.

It's worth noting that while sugar acids have important applications in various industries, they can also contribute to tooth decay and other health problems when consumed in excess. Therefore, it's important to consume them in moderation as part of a balanced diet.

Carbon radioisotopes are radioactive isotopes of carbon, which is an naturally occurring chemical element with the atomic number 6. The most common and stable isotope of carbon is carbon-12 (^12C), but there are also several radioactive isotopes, including carbon-11 (^11C), carbon-14 (^14C), and carbon-13 (^13C). These radioisotopes have different numbers of neutrons in their nuclei, which makes them unstable and causes them to emit radiation.

Carbon-11 has a half-life of about 20 minutes and is used in medical imaging techniques such as positron emission tomography (PET) scans. It is produced by bombarding nitrogen-14 with protons in a cyclotron.

Carbon-14, also known as radiocarbon, has a half-life of about 5730 years and is used in archaeology and geology to date organic materials. It is produced naturally in the atmosphere by cosmic rays.

Carbon-13 is stable and has a natural abundance of about 1.1% in carbon. It is not radioactive, but it can be used as a tracer in medical research and in the study of metabolic processes.

Carbon isotopes are variants of the chemical element carbon that have different numbers of neutrons in their atomic nuclei. The most common and stable isotope of carbon is carbon-12 (^{12}C), which contains six protons and six neutrons. However, carbon can also come in other forms, known as isotopes, which contain different numbers of neutrons.

Carbon-13 (^{13}C) is a stable isotope of carbon that contains seven neutrons in its nucleus. It makes up about 1.1% of all carbon found on Earth and is used in various scientific applications, such as in tracing the metabolic pathways of organisms or in studying the age of fossilized materials.

Carbon-14 (^{14}C), also known as radiocarbon, is a radioactive isotope of carbon that contains eight neutrons in its nucleus. It is produced naturally in the atmosphere through the interaction of cosmic rays with nitrogen gas. Carbon-14 has a half-life of about 5,730 years, which makes it useful for dating organic materials, such as archaeological artifacts or fossils, up to around 60,000 years old.

Carbon isotopes are important in many scientific fields, including geology, biology, and medicine, and are used in a variety of applications, from studying the Earth's climate history to diagnosing medical conditions.

Reverse-phase chromatography is a type of liquid chromatography that is commonly used in analytical chemistry and biochemistry to separate, identify, and purify complex mixtures of chemicals or biological molecules. In this technique, the stationary phase is a nonpolar solid, such as octadecyl silica (ODS) or C18, which is coated with a polar solvent, while the mobile phase is a nonpolar solvent, such as methanol or acetonitrile.

The term "reverse-phase" refers to the fact that the polarity of the stationary and mobile phases is reversed compared to normal-phase chromatography. In normal-phase chromatography, the stationary phase is polar and the mobile phase is nonpolar, which results in the separation of analytes based on their polarity. However, in reverse-phase chromatography, the stationary phase is nonpolar and the mobile phase is polar, which means that the separation of analytes is based on their hydrophobicity or hydrophilicity.

In reverse-phase chromatography, hydrophobic molecules elute more slowly than hydrophilic molecules because they have a stronger affinity for the nonpolar stationary phase. The retention time of an analyte can be adjusted by changing the composition of the mobile phase or the pH of the solution. This technique is widely used in the analysis of drugs, metabolites, peptides, proteins, and other biological molecules.

Methanol, also known as methyl alcohol or wood alcohol, is a volatile, colorless, flammable liquid with a distinctive odor similar to that of ethanol (drinking alcohol). It is used in various industrial applications such as the production of formaldehyde, acetic acid, and other chemicals. In the medical field, methanol is considered a toxic alcohol that can cause severe intoxication and metabolic disturbances when ingested or improperly consumed. Methanol poisoning can lead to neurological symptoms, blindness, and even death if not treated promptly and effectively.

Glucose is a simple monosaccharide (or single sugar) that serves as the primary source of energy for living organisms. It's a fundamental molecule in biology, often referred to as "dextrose" or "grape sugar." Glucose has the molecular formula C6H12O6 and is vital to the functioning of cells, especially those in the brain and nervous system.

In the body, glucose is derived from the digestion of carbohydrates in food, and it's transported around the body via the bloodstream to cells where it can be used for energy. Cells convert glucose into a usable form through a process called cellular respiration, which involves a series of metabolic reactions that generate adenosine triphosphate (ATP)—the main currency of energy in cells.

Glucose is also stored in the liver and muscles as glycogen, a polysaccharide (multiple sugar) that can be broken down back into glucose when needed for energy between meals or during physical activity. Maintaining appropriate blood glucose levels is crucial for overall health, and imbalances can lead to conditions such as diabetes mellitus.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Environmental monitoring is the systematic and ongoing surveillance, measurement, and assessment of environmental parameters, pollutants, or other stressors in order to evaluate potential impacts on human health, ecological systems, or compliance with regulatory standards. This process typically involves collecting and analyzing data from various sources, such as air, water, soil, and biota, and using this information to inform decisions related to public health, environmental protection, and resource management.

In medical terms, environmental monitoring may refer specifically to the assessment of environmental factors that can impact human health, such as air quality, water contamination, or exposure to hazardous substances. This type of monitoring is often conducted in occupational settings, where workers may be exposed to potential health hazards, as well as in community-based settings, where environmental factors may contribute to public health issues. The goal of environmental monitoring in a medical context is to identify and mitigate potential health risks associated with environmental exposures, and to promote healthy and safe environments for individuals and communities.

Cholesterol is a type of lipid (fat) molecule that is an essential component of cell membranes and is also used to make certain hormones and vitamins in the body. It is produced by the liver and is also obtained from animal-derived foods such as meat, dairy products, and eggs.

Cholesterol does not mix with blood, so it is transported through the bloodstream by lipoproteins, which are particles made up of both lipids and proteins. There are two main types of lipoproteins that carry cholesterol: low-density lipoproteins (LDL), also known as "bad" cholesterol, and high-density lipoproteins (HDL), also known as "good" cholesterol.

High levels of LDL cholesterol in the blood can lead to a buildup of cholesterol in the walls of the arteries, increasing the risk of heart disease and stroke. On the other hand, high levels of HDL cholesterol are associated with a lower risk of these conditions because HDL helps remove LDL cholesterol from the bloodstream and transport it back to the liver for disposal.

It is important to maintain healthy levels of cholesterol through a balanced diet, regular exercise, and sometimes medication if necessary. Regular screening is also recommended to monitor cholesterol levels and prevent health complications.

Oligosaccharides are complex carbohydrates composed of relatively small numbers (3-10) of monosaccharide units joined together by glycosidic linkages. They occur naturally in foods such as milk, fruits, vegetables, and legumes. In the body, oligosaccharides play important roles in various biological processes, including cell recognition, signaling, and protection against pathogens.

There are several types of oligosaccharides, classified based on their structures and functions. Some common examples include:

1. Disaccharides: These consist of two monosaccharide units, such as sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).
2. Trisaccharides: These contain three monosaccharide units, like maltotriose (glucose + glucose + glucose) and raffinose (galactose + glucose + fructose).
3. Oligosaccharides found in human milk: Human milk contains unique oligosaccharides that serve as prebiotics, promoting the growth of beneficial bacteria in the gut. These oligosaccharides also help protect infants from pathogens by acting as decoy receptors and inhibiting bacterial adhesion to intestinal cells.
4. N-linked and O-linked glycans: These are oligosaccharides attached to proteins in the body, playing crucial roles in protein folding, stability, and function.
5. Plant-derived oligosaccharides: Fructooligosaccharides (FOS) and galactooligosaccharides (GOS) are examples of plant-derived oligosaccharides that serve as prebiotics, promoting the growth of beneficial gut bacteria.

Overall, oligosaccharides have significant impacts on human health and disease, particularly in relation to gastrointestinal function, immunity, and inflammation.

Sugar alcohols, also known as polyols, are carbohydrates that are chemically similar to sugar but have a different molecular structure. They occur naturally in some fruits and vegetables, but most sugar alcohols used in food products are manufactured.

The chemical structure of sugar alcohols contains a hydroxyl group (-OH) instead of a hydrogen and a ketone or aldehyde group, which makes them less sweet than sugar and have fewer calories. They are not completely absorbed by the body, so they do not cause a rapid increase in blood glucose levels, making them a popular sweetener for people with diabetes.

Common sugar alcohols used in food products include xylitol, sorbitol, mannitol, erythritol, and maltitol. They are often used as sweeteners in sugar-free and low-sugar foods such as candy, chewing gum, baked goods, and beverages.

However, consuming large amounts of sugar alcohols can cause digestive symptoms such as bloating, gas, and diarrhea, due to their partial absorption in the gut. Therefore, it is recommended to consume them in moderation.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (free radicals) and the body's ability to detoxify them or repair the damage they cause. This imbalance can lead to cellular damage, oxidation of proteins, lipids, and DNA, disruption of cellular functions, and activation of inflammatory responses. Prolonged or excessive oxidative stress has been linked to various health conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and aging-related diseases.

Acetates, in a medical context, most commonly refer to compounds that contain the acetate group, which is an functional group consisting of a carbon atom bonded to two hydrogen atoms and an oxygen atom (-COO-). An example of an acetate is sodium acetate (CH3COONa), which is a salt formed from acetic acid (CH3COOH) and is often used as a buffering agent in medical solutions.

Acetates can also refer to a group of medications that contain acetate as an active ingredient, such as magnesium acetate, which is used as a laxative, or calcium acetate, which is used to treat high levels of phosphate in the blood.

In addition, acetates can also refer to a process called acetylation, which is the addition of an acetyl group (-COCH3) to a molecule. This process can be important in the metabolism and regulation of various substances within the body.

Microsomes, liver refers to a subcellular fraction of liver cells (hepatocytes) that are obtained during tissue homogenization and subsequent centrifugation. These microsomal fractions are rich in membranous structures known as the endoplasmic reticulum (ER), particularly the rough ER. They are involved in various important cellular processes, most notably the metabolism of xenobiotics (foreign substances) including drugs, toxins, and carcinogens.

The liver microsomes contain a variety of enzymes, such as cytochrome P450 monooxygenases, that are crucial for phase I drug metabolism. These enzymes help in the oxidation, reduction, or hydrolysis of xenobiotics, making them more water-soluble and facilitating their excretion from the body. Additionally, liver microsomes also host other enzymes involved in phase II conjugation reactions, where the metabolites from phase I are further modified by adding polar molecules like glucuronic acid, sulfate, or acetyl groups.

In summary, liver microsomes are a subcellular fraction of liver cells that play a significant role in the metabolism and detoxification of xenobiotics, contributing to the overall protection and maintenance of cellular homeostasis within the body.

Sulfur compounds refer to chemical substances that contain sulfur atoms. Sulfur can form bonds with many other elements, including carbon, hydrogen, oxygen, and nitrogen, among others. As a result, there is a wide variety of sulfur compounds with different structures and properties. Some common examples of sulfur compounds include hydrogen sulfide (H2S), sulfur dioxide (SO2), and sulfonic acids (R-SO3H).

In the medical field, sulfur compounds have various applications. For instance, some are used as drugs or drug precursors, while others are used in the production of medical devices or as disinfectants. Sulfur-containing amino acids, such as methionine and cysteine, are essential components of proteins and play crucial roles in many biological processes.

However, some sulfur compounds can also be harmful to human health. For example, exposure to high levels of hydrogen sulfide or sulfur dioxide can cause respiratory problems, while certain organosulfur compounds found in crude oil and coal tar have been linked to an increased risk of cancer. Therefore, it is essential to handle and dispose of sulfur compounds properly to minimize potential health hazards.

Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.

Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.

Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.

Industrial fungicides are antimicrobial agents used to prevent, destroy, or inhibit the growth of fungi and their spores in industrial settings. These can include uses in manufacturing processes, packaging materials, textiles, paints, and other industrial products. They work by interfering with the cellular structure or metabolic processes of fungi, thereby preventing their growth or reproduction. Examples of industrial fungicides include:

* Sodium hypochlorite (bleach)
* Formaldehyde
* Glutaraldehyde
* Quaternary ammonium compounds
* Peracetic acid
* Chlorhexidine
* Iodophors

It's important to note that some of these fungicides can be harmful or toxic to humans and other organisms, so they must be used with caution and in accordance with safety guidelines.

Terphenyl compounds are organic substances that consist of three phenyl groups (benzene rings) connected in a linear fashion through single carbon-carbon bonds. They can be either symmetrical or unsymmetrical, depending on the arrangement of the phenyl groups and the type of substituents attached to them. These compounds are known for their high melting points, chemical stability, and electrical insulation properties, making them useful in various industrial applications such as lubricants, plasticizers, and high-temperature resins.

Solid-phase extraction (SPE) is a method used in analytical chemistry and biochemistry to extract, separate, or clean up specific components from a complex matrix, such as a biological sample. It involves the use of a solid phase, typically a packed bed of sorbent material, held within a cartridge or column. The sample mixture is passed through the column, and the components of interest are selectively retained by the sorbent while other components pass through.

The analytes can then be eluted from the sorbent using a small volume of a suitable solvent, resulting in a more concentrated and purified fraction that can be analyzed using various techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), or mass spectrometry.

The solid phase used in SPE can vary depending on the nature of the analytes and the matrix, with different sorbents offering varying degrees of selectivity and capacity for specific compounds. Commonly used sorbents include silica-based materials, polymeric resins, and ion exchange materials.

Overall, solid-phase extraction is a powerful tool in sample preparation, allowing for the isolation and concentration of target analytes from complex matrices, thereby improving the sensitivity and selectivity of downstream analytical techniques.

Amino acids are organic compounds that serve as the building blocks of proteins. They consist of a central carbon atom, also known as the alpha carbon, which is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a variable side chain (R group). The R group can be composed of various combinations of atoms such as hydrogen, oxygen, sulfur, nitrogen, and carbon, which determine the unique properties of each amino acid.

There are 20 standard amino acids that are encoded by the genetic code and incorporated into proteins during translation. These include:

1. Alanine (Ala)
2. Arginine (Arg)
3. Asparagine (Asn)
4. Aspartic acid (Asp)
5. Cysteine (Cys)
6. Glutamine (Gln)
7. Glutamic acid (Glu)
8. Glycine (Gly)
9. Histidine (His)
10. Isoleucine (Ile)
11. Leucine (Leu)
12. Lysine (Lys)
13. Methionine (Met)
14. Phenylalanine (Phe)
15. Proline (Pro)
16. Serine (Ser)
17. Threonine (Thr)
18. Tryptophan (Trp)
19. Tyrosine (Tyr)
20. Valine (Val)

Additionally, there are several non-standard or modified amino acids that can be incorporated into proteins through post-translational modifications, such as hydroxylation, methylation, and phosphorylation. These modifications expand the functional diversity of proteins and play crucial roles in various cellular processes.

Amino acids are essential for numerous biological functions, including protein synthesis, enzyme catalysis, neurotransmitter production, energy metabolism, and immune response regulation. Some amino acids can be synthesized by the human body (non-essential), while others must be obtained through dietary sources (essential).

Two-dimensional (2D) gel electrophoresis is a type of electrophoretic technique used in the separation and analysis of complex protein mixtures. This method combines two types of electrophoresis – isoelectric focusing (IEF) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) – to separate proteins based on their unique physical and chemical properties in two dimensions.

In the first dimension, IEF separates proteins according to their isoelectric points (pI), which is the pH at which a protein carries no net electrical charge. The proteins are focused into narrow zones along a pH gradient established within a gel strip. In the second dimension, SDS-PAGE separates the proteins based on their molecular weights by applying an electric field perpendicular to the first dimension.

The separated proteins form distinct spots on the 2D gel, which can be visualized using various staining techniques. The resulting protein pattern provides valuable information about the composition and modifications of the protein mixture, enabling researchers to identify and compare different proteins in various samples. Two-dimensional gel electrophoresis is widely used in proteomics research, biomarker discovery, and quality control in protein production.

Indicator dilution techniques are a group of methods used in medicine and research to measure various physiological variables, such as cardiac output or cerebral blood flow. These techniques involve introducing a known quantity of an indicator substance (like a dye or a radioactive tracer) into the system being studied and then measuring its concentration over time at a specific location downstream.

The basic principle behind these techniques is that the concentration of the indicator substance will be inversely proportional to the flow rate of the fluid through which it is moving. By measuring the concentration of the indicator substance at different points in time, researchers can calculate the flow rate using mathematical formulas.

Indicator dilution techniques are widely used in clinical and research settings because they are relatively non-invasive and can provide accurate and reliable measurements of various physiological variables. Some common examples of indicator dilution techniques include thermodilution, dye dilution, and Fick principle-based methods.

I'm sorry for any confusion, but "hydrocarbons" is not a term that has a specific medical definition. Hydrocarbons are organic compounds consisting entirely of hydrogen and carbon. They are primarily used in industry as fuel, lubricants, and as raw materials for the production of plastics, fibers, and other chemicals.

However, in a broader scientific context, hydrocarbons can be relevant to medical discussions. For instance, in toxicology, exposure to certain types of hydrocarbons (like those found in gasoline or solvents) can lead to poisoning and related health issues. In environmental medicine, the pollution of air, water, and soil with hydrocarbons is a concern due to potential health effects.

But in general clinical medicine, 'hydrocarbons' wouldn't have a specific definition.

Secondary Ion Mass Spectrometry (SIMS) is a type of mass spectrometry used for the analysis of solid surfaces. It is based on the emission of secondary ions generated by bombarding the sample surface with a focused primary ion beam. The emitted secondary ions are then analyzed according to their mass-to-charge ratio, providing information about the elemental and isotopic composition of the sample surface at a very high spatial resolution (down to a few nanometers).

SIMS can be used for various applications, such as the analysis of inorganic and organic materials, including polymers, biomaterials, and semiconductors. It is also commonly used for depth profiling, which allows for the measurement of elemental concentration as a function of depth below the sample surface.

The primary ion beam can be made up of various elements, such as oxygen, cesium, gallium, or gold, and the choice of primary ions depends on the specific application and the type of information required from the analysis. The most common SIMS techniques are dynamic SIMS (DSIMS) and static SIMS (SSIMS), which differ in the primary ion dose used for the analysis and the resulting level of surface damage.

Isotopes are variants of a chemical element that have the same number of protons in their atomic nucleus, but a different number of neutrons. This means they have different atomic masses, but share similar chemical properties. Some isotopes are stable and do not decay naturally, while others are unstable and radioactive, undergoing radioactive decay and emitting radiation in the process. These radioisotopes are often used in medical imaging and treatment procedures.

Molecular weight, also known as molecular mass, is the mass of a molecule. It is expressed in units of atomic mass units (amu) or daltons (Da). Molecular weight is calculated by adding up the atomic weights of each atom in a molecule. It is a useful property in chemistry and biology, as it can be used to determine the concentration of a substance in a solution, or to calculate the amount of a substance that will react with another in a chemical reaction.

Pesticide residues refer to the remaining pesticide chemicals, including their metabolites and degradation products, that are present in or on food commodities or environmental samples after a pesticide application has ended. These residues can result from agricultural use, such as spraying crops to control pests, or from non-agricultural uses, like treating buildings for termite control.

Regulatory agencies establish maximum residue limits (MRLs) to ensure that the levels of pesticide residues in food and feed are below those that may pose a risk to human health. Monitoring programs are in place to check compliance with these MRLs, and enforcement actions can be taken if violations occur.

It's important to note that not all pesticide residues are harmful, as some pesticides degrade into harmless compounds over time or leave behind residues below levels of concern for human health. However, long-term exposure to even low levels of certain pesticide residues may still pose a risk and should be avoided when possible.

Bile is a digestive fluid that is produced by the liver and stored in the gallbladder. It plays an essential role in the digestion and absorption of fats and fat-soluble vitamins in the small intestine. Bile consists of bile salts, bilirubin, cholesterol, phospholipids, electrolytes, and water.

Bile salts are amphipathic molecules that help to emulsify fats into smaller droplets, increasing their surface area and allowing for more efficient digestion by enzymes such as lipase. Bilirubin is a breakdown product of hemoglobin from red blood cells and gives bile its characteristic greenish-brown color.

Bile is released into the small intestine in response to food, particularly fats, entering the digestive tract. It helps to break down large fat molecules into smaller ones that can be absorbed through the walls of the intestines and transported to other parts of the body for energy or storage.

Fast Atom Bombardment (FAB) Mass Spectrometry is a technique used for determining the mass of ions in a sample. In FAB-MS, the sample is mixed with a matrix material and then bombarded with a beam of fast atoms, usually xenon or cesium. This bombardment leads to the formation of ions from the sample which can then be detected and measured using a mass analyzer. The resulting mass spectrum provides information about the molecular weight and structure of the sample molecules. FAB-MS is particularly useful for the analysis of large, thermally labile, or polar molecules that may not ionize well by other methods.

Spectrophotometry, Ultraviolet (UV-Vis) is a type of spectrophotometry that measures how much ultraviolet (UV) and visible light is absorbed or transmitted by a sample. It uses a device called a spectrophotometer to measure the intensity of light at different wavelengths as it passes through a sample. The resulting data can be used to determine the concentration of specific components within the sample, identify unknown substances, or evaluate the physical and chemical properties of materials.

UV-Vis spectroscopy is widely used in various fields such as chemistry, biology, pharmaceuticals, and environmental science. It can detect a wide range of substances including organic compounds, metal ions, proteins, nucleic acids, and dyes. The technique is non-destructive, meaning that the sample remains unchanged after the measurement.

In UV-Vis spectroscopy, the sample is placed in a cuvette or other container, and light from a source is directed through it. The light then passes through a monochromator, which separates it into its component wavelengths. The monochromatic light is then directed through the sample, and the intensity of the transmitted or absorbed light is measured by a detector.

The resulting absorption spectrum can provide information about the concentration and identity of the components in the sample. For example, if a compound has a known absorption maximum at a specific wavelength, its concentration can be determined by measuring the absorbance at that wavelength and comparing it to a standard curve.

Overall, UV-Vis spectrophotometry is a versatile and powerful analytical technique for quantitative and qualitative analysis of various samples in different fields.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

A plant extract is a preparation containing chemical constituents that have been extracted from a plant using a solvent. The resulting extract may contain a single compound or a mixture of several compounds, depending on the extraction process and the specific plant material used. These extracts are often used in various industries including pharmaceuticals, nutraceuticals, cosmetics, and food and beverage, due to their potential therapeutic or beneficial properties. The composition of plant extracts can vary widely, and it is important to ensure their quality, safety, and efficacy before use in any application.

Glucuronides are conjugated compounds formed in the liver by the attachment of glucuronic acid to a variety of molecules, including drugs, hormones, and environmental toxins. This process, known as glucuronidation, is catalyzed by enzymes called UDP-glucuronosyltransferases (UGTs) and increases the water solubility of these compounds, allowing them to be more easily excreted from the body through urine or bile.

Glucuronidation plays a crucial role in the detoxification and elimination of many substances, including drugs and toxins. However, in some cases, glucuronides can also be hydrolyzed back into their original forms by enzymes called β-glucuronidases, which can lead to reabsorption of the parent compound and prolong its effects or toxicity.

Overall, understanding the metabolism and disposition of glucuronides is important for predicting drug interactions, pharmacokinetics, and potential adverse effects.

Polysaccharides are complex carbohydrates consisting of long chains of monosaccharide units (simple sugars) bonded together by glycosidic linkages. They can be classified based on the type of monosaccharides and the nature of the bonds that connect them.

Polysaccharides have various functions in living organisms. For example, starch and glycogen serve as energy storage molecules in plants and animals, respectively. Cellulose provides structural support in plants, while chitin is a key component of fungal cell walls and arthropod exoskeletons.

Some polysaccharides also have important roles in the human body, such as being part of the extracellular matrix (e.g., hyaluronic acid) or acting as blood group antigens (e.g., ABO blood group substances).

An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net electric charge. Cations are positively charged ions, which have lost electrons, while anions are negatively charged ions, which have gained electrons. Ions can play a significant role in various physiological processes within the human body, including enzyme function, nerve impulse transmission, and maintenance of acid-base balance. They also contribute to the formation of salts and buffer systems that help regulate fluid composition and pH levels in different bodily fluids.

Glyoxal is an organic compound with the formula CH(O)CHO. It is a colorless liquid that is used primarily as a building block in the synthesis of other chemicals, including pharmaceuticals and agrochemicals. Glyoxal is also found in small amounts in the environment, including in tobacco smoke and in certain foods.

In the body, glyoxal can be produced as a byproduct of normal metabolic processes, particularly when sugars are broken down. Under some circumstances, high levels of glyoxal may contribute to the development of chronic diseases, including diabetes and its complications. This is because glyoxal can react with proteins and other biological molecules in the body, forming advanced glycation end-products (AGEs) that can disrupt normal cellular function and contribute to tissue damage. However, more research is needed to fully understand the role of glyoxal in human health and disease.

Phenols, also known as phenolic acids or phenol derivatives, are a class of chemical compounds consisting of a hydroxyl group (-OH) attached to an aromatic hydrocarbon ring. In the context of medicine and biology, phenols are often referred to as a type of antioxidant that can be found in various foods and plants.

Phenols have the ability to neutralize free radicals, which are unstable molecules that can cause damage to cells and contribute to the development of chronic diseases such as cancer, heart disease, and neurodegenerative disorders. Some common examples of phenolic compounds include gallic acid, caffeic acid, ferulic acid, and ellagic acid, among many others.

Phenols can also have various pharmacological activities, including anti-inflammatory, antimicrobial, and analgesic effects. However, some phenolic compounds can also be toxic or irritating to the body in high concentrations, so their use as therapeutic agents must be carefully monitored and controlled.

Hydroxylation is a biochemical process that involves the addition of a hydroxyl group (-OH) to a molecule, typically a steroid or xenobiotic compound. This process is primarily catalyzed by enzymes called hydroxylases, which are found in various tissues throughout the body.

In the context of medicine and biochemistry, hydroxylation can have several important functions:

1. Drug metabolism: Hydroxylation is a common way that the liver metabolizes drugs and other xenobiotic compounds. By adding a hydroxyl group to a drug molecule, it becomes more polar and water-soluble, which facilitates its excretion from the body.
2. Steroid hormone biosynthesis: Hydroxylation is an essential step in the biosynthesis of many steroid hormones, including cortisol, aldosterone, and the sex hormones estrogen and testosterone. These hormones are synthesized from cholesterol through a series of enzymatic reactions that involve hydroxylation at various steps.
3. Vitamin D activation: Hydroxylation is also necessary for the activation of vitamin D in the body. In order to become biologically active, vitamin D must undergo two successive hydroxylations, first in the liver and then in the kidneys.
4. Toxin degradation: Some toxic compounds can be rendered less harmful through hydroxylation. For example, phenol, a toxic compound found in cigarette smoke and some industrial chemicals, can be converted to a less toxic form through hydroxylation by enzymes in the liver.

Overall, hydroxylation is an important biochemical process that plays a critical role in various physiological functions, including drug metabolism, hormone biosynthesis, and toxin degradation.

A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.

Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.

Mycolic acids are complex, long-chain fatty acids that are a major component of the cell wall in mycobacteria, including the bacteria responsible for tuberculosis and leprosy. These acids contribute to the impermeability and resistance to chemical agents of the mycobacterial cell wall, making these organisms difficult to eradicate. Mycolic acids are unique to mycobacteria and some related actinomycetes, and their analysis can be useful in the identification and classification of these bacteria.

Disaccharides are a type of carbohydrate that is made up of two monosaccharide units bonded together. Monosaccharides are simple sugars, such as glucose, fructose, or galactose. When two monosaccharides are joined together through a condensation reaction, they form a disaccharide.

The most common disaccharides include:

* Sucrose (table sugar), which is composed of one glucose molecule and one fructose molecule.
* Lactose (milk sugar), which is composed of one glucose molecule and one galactose molecule.
* Maltose (malt sugar), which is composed of two glucose molecules.

Disaccharides are broken down into their component monosaccharides during digestion by enzymes called disaccharidases, which are located in the brush border of the small intestine. These enzymes catalyze the hydrolysis of the glycosidic bond that links the two monosaccharides together, releasing them to be absorbed into the bloodstream and used for energy.

Disorders of disaccharide digestion and absorption can lead to various symptoms, such as bloating, diarrhea, and abdominal pain. For example, lactose intolerance is a common condition in which individuals lack sufficient levels of the enzyme lactase, leading to an inability to properly digest lactose and resulting in gastrointestinal symptoms.

Pharmaceutical preparations refer to the various forms of medicines that are produced by pharmaceutical companies, which are intended for therapeutic or prophylactic use. These preparations consist of an active ingredient (the drug) combined with excipients (inactive ingredients) in a specific formulation and dosage form.

The active ingredient is the substance that has a therapeutic effect on the body, while the excipients are added to improve the stability, palatability, bioavailability, or administration of the drug. Examples of pharmaceutical preparations include tablets, capsules, solutions, suspensions, emulsions, ointments, creams, and injections.

The production of pharmaceutical preparations involves a series of steps that ensure the quality, safety, and efficacy of the final product. These steps include the selection and testing of raw materials, formulation development, manufacturing, packaging, labeling, and storage. Each step is governed by strict regulations and guidelines to ensure that the final product meets the required standards for use in medical practice.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Indicators and reagents are terms commonly used in the field of clinical chemistry and laboratory medicine. Here are their definitions:

1. Indicator: An indicator is a substance that changes its color or other physical properties in response to a chemical change, such as a change in pH, oxidation-reduction potential, or the presence of a particular ion or molecule. Indicators are often used in laboratory tests to monitor or signal the progress of a reaction or to indicate the end point of a titration. A familiar example is the use of phenolphthalein as a pH indicator in acid-base titrations, which turns pink in basic solutions and colorless in acidic solutions.

2. Reagent: A reagent is a substance that is added to a system (such as a sample or a reaction mixture) to bring about a chemical reaction, test for the presence or absence of a particular component, or measure the concentration of a specific analyte. Reagents are typically chemicals with well-defined and consistent properties, allowing them to be used reliably in analytical procedures. Examples of reagents include enzymes, antibodies, dyes, metal ions, and organic compounds. In laboratory settings, reagents are often prepared and standardized according to strict protocols to ensure their quality and performance in diagnostic tests and research applications.

Brain chemistry refers to the chemical processes that occur within the brain, particularly those involving neurotransmitters, neuromodulators, and neuropeptides. These chemicals are responsible for transmitting signals between neurons (nerve cells) in the brain, allowing for various cognitive, emotional, and physical functions.

Neurotransmitters are chemical messengers that transmit signals across the synapse (the tiny gap between two neurons). Examples of neurotransmitters include dopamine, serotonin, norepinephrine, GABA (gamma-aminobutyric acid), and glutamate. Each neurotransmitter has a specific role in brain function, such as regulating mood, motivation, attention, memory, and movement.

Neuromodulators are chemicals that modify the effects of neurotransmitters on neurons. They can enhance or inhibit the transmission of signals between neurons, thereby modulating brain activity. Examples of neuromodulators include acetylcholine, histamine, and substance P.

Neuropeptides are small protein-like molecules that act as neurotransmitters or neuromodulators. They play a role in various physiological functions, such as pain perception, stress response, and reward processing. Examples of neuropeptides include endorphins, enkephalins, and oxytocin.

Abnormalities in brain chemistry can lead to various neurological and psychiatric conditions, such as depression, anxiety disorders, schizophrenia, Parkinson's disease, and Alzheimer's disease. Understanding brain chemistry is crucial for developing effective treatments for these conditions.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Lipids are a broad group of organic compounds that are insoluble in water but soluble in nonpolar organic solvents. They include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, and phospholipids. Lipids serve many important functions in the body, including energy storage, acting as structural components of cell membranes, and serving as signaling molecules. High levels of certain lipids, particularly cholesterol and triglycerides, in the blood are associated with an increased risk of cardiovascular disease.

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

Environmental pollutants are defined as any substances or energy (such as noise, heat, or light) that are present in the environment and can cause harm or discomfort to humans or other living organisms, or damage the natural ecosystems. These pollutants can come from a variety of sources, including industrial processes, transportation, agriculture, and household activities. They can be in the form of gases, liquids, solids, or radioactive materials, and can contaminate air, water, and soil. Examples include heavy metals, pesticides, volatile organic compounds (VOCs), particulate matter, and greenhouse gases.

It is important to note that the impact of environmental pollutants on human health and the environment can be acute (short-term) or chronic (long-term) and it depends on the type, concentration, duration and frequency of exposure. Some common effects of environmental pollutants include respiratory problems, cancer, neurological disorders, reproductive issues, and developmental delays in children.

It is important to monitor, control and reduce the emissions of these pollutants through regulations, technology advancements, and sustainable practices to protect human health and the environment.

Peptide mapping is a technique used in proteomics and analytical chemistry to analyze and identify the sequence and structure of peptides or proteins. This method involves breaking down a protein into smaller peptide fragments using enzymatic or chemical digestion, followed by separation and identification of these fragments through various analytical techniques such as liquid chromatography (LC) and mass spectrometry (MS).

The resulting peptide map serves as a "fingerprint" of the protein, providing information about its sequence, modifications, and structure. Peptide mapping can be used for a variety of applications, including protein identification, characterization of post-translational modifications, and monitoring of protein degradation or cleavage.

In summary, peptide mapping is a powerful tool in proteomics that enables the analysis and identification of proteins and their modifications at the peptide level.

Amines are organic compounds that contain a basic nitrogen atom with a lone pair of electrons. They are derived from ammonia (NH3) by replacing one or more hydrogen atoms with alkyl or aryl groups. The nomenclature of amines follows the substitutive type, where the parent compound is named as an aliphatic or aromatic hydrocarbon, and the functional group "amine" is designated as a suffix or prefix.

Amines are classified into three types based on the number of carbon atoms attached to the nitrogen atom:

1. Primary (1°) amines: One alkyl or aryl group is attached to the nitrogen atom.
2. Secondary (2°) amines: Two alkyl or aryl groups are attached to the nitrogen atom.
3. Tertiary (3°) amines: Three alkyl or aryl groups are attached to the nitrogen atom.

Quaternary ammonium salts have four organic groups attached to the nitrogen atom and a positive charge, with anions balancing the charge.

Amines have a wide range of applications in the chemical industry, including pharmaceuticals, dyes, polymers, and solvents. They also play a significant role in biological systems as neurotransmitters, hormones, and cell membrane components.

Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

I'm sorry for any confusion, but "Microchemistry" is not a commonly used term in medicine. It is, however, a branch of chemistry that deals with the separation, identification, and analysis of chemical substances in minute quantities. This field can be applied in various scientific disciplines, including forensic science, environmental science, and materials science.

In the medical field, you might encounter similar concepts under terms like "microanalysis" or "clinical chemistry," which refer to the identification and measurement of chemical components in body fluids (like blood or urine) for diagnostic purposes. But again, "Microchemistry" is not a standard term used in this context.

A case-control study is an observational research design used to identify risk factors or causes of a disease or health outcome. In this type of study, individuals with the disease or condition (cases) are compared with similar individuals who do not have the disease or condition (controls). The exposure history or other characteristics of interest are then compared between the two groups to determine if there is an association between the exposure and the disease.

Case-control studies are often used when it is not feasible or ethical to conduct a randomized controlled trial, as they can provide valuable insights into potential causes of diseases or health outcomes in a relatively short period of time and at a lower cost than other study designs. However, because case-control studies rely on retrospective data collection, they are subject to biases such as recall bias and selection bias, which can affect the validity of the results. Therefore, it is important to carefully design and conduct case-control studies to minimize these potential sources of bias.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

Species specificity is a term used in the field of biology, including medicine, to refer to the characteristic of a biological entity (such as a virus, bacterium, or other microorganism) that allows it to interact exclusively or preferentially with a particular species. This means that the biological entity has a strong affinity for, or is only able to infect, a specific host species.

For example, HIV is specifically adapted to infect human cells and does not typically infect other animal species. Similarly, some bacterial toxins are species-specific and can only affect certain types of animals or humans. This concept is important in understanding the transmission dynamics and host range of various pathogens, as well as in developing targeted therapies and vaccines.

An amide is a functional group or a compound that contains a carbonyl group (a double-bonded carbon atom) and a nitrogen atom. The nitrogen atom is connected to the carbonyl carbon atom by a single bond, and it also has a lone pair of electrons. Amides are commonly found in proteins and peptides, where they form amide bonds (also known as peptide bonds) between individual amino acids.

The general structure of an amide is R-CO-NHR', where R and R' can be alkyl or aryl groups. Amides can be classified into several types based on the nature of R and R' substituents:

* Primary amides: R-CO-NH2
* Secondary amides: R-CO-NHR'
* Tertiary amides: R-CO-NR''R'''

Amides have several important chemical properties. They are generally stable and resistant to hydrolysis under neutral or basic conditions, but they can be hydrolyzed under acidic conditions or with strong bases. Amides also exhibit a characteristic infrared absorption band around 1650 cm-1 due to the carbonyl stretching vibration.

In addition to their prevalence in proteins and peptides, amides are also found in many natural and synthetic compounds, including pharmaceuticals, dyes, and polymers. They have a wide range of applications in chemistry, biology, and materials science.

A chemical model is a simplified representation or description of a chemical system, based on the laws of chemistry and physics. It is used to explain and predict the behavior of chemicals and chemical reactions. Chemical models can take many forms, including mathematical equations, diagrams, and computer simulations. They are often used in research, education, and industry to understand complex chemical processes and develop new products and technologies.

For example, a chemical model might be used to describe the way that atoms and molecules interact in a particular reaction, or to predict the properties of a new material. Chemical models can also be used to study the behavior of chemicals at the molecular level, such as how they bind to each other or how they are affected by changes in temperature or pressure.

It is important to note that chemical models are simplifications of reality and may not always accurately represent every aspect of a chemical system. They should be used with caution and validated against experimental data whenever possible.

Phospholipids are a major class of lipids that consist of a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. The head is composed of a phosphate group, which is often bound to an organic molecule such as choline, ethanolamine, serine or inositol. The tails are made up of two fatty acid chains.

Phospholipids are a key component of cell membranes and play a crucial role in maintaining the structural integrity and function of the cell. They form a lipid bilayer, with the hydrophilic heads facing outwards and the hydrophobic tails facing inwards, creating a barrier that separates the interior of the cell from the outside environment.

Phospholipids are also involved in various cellular processes such as signal transduction, intracellular trafficking, and protein function regulation. Additionally, they serve as emulsifiers in the digestive system, helping to break down fats in the diet.

Chemical fractionation is a process used in analytical chemistry to separate and isolate individual components or fractions from a mixture based on their chemical properties. This technique typically involves the use of various chemical reactions, such as precipitation, extraction, or chromatography, to selectively interact with specific components in the mixture and purify them.

In the context of medical research or clinical analysis, chemical fractionation may be used to isolate and identify individual compounds in a complex biological sample, such as blood, urine, or tissue. For example, fractionating a urine sample might involve separating out various metabolites, proteins, or other molecules based on their solubility, charge, or other chemical properties, allowing researchers to study the individual components and their roles in health and disease.

It's worth noting that while chemical fractionation can be a powerful tool for analyzing complex mixtures, it can also be time-consuming and technically challenging, requiring specialized equipment and expertise to perform accurately and reliably.

Mixed Function Oxygenases (MFOs) are a type of enzyme that catalyze the addition of one atom each from molecular oxygen (O2) to a substrate, while reducing the other oxygen atom to water. These enzymes play a crucial role in the metabolism of various endogenous and exogenous compounds, including drugs, carcinogens, and environmental pollutants.

MFOs are primarily located in the endoplasmic reticulum of cells and consist of two subunits: a flavoprotein component that contains FAD or FMN as a cofactor, and an iron-containing heme protein. The most well-known example of MFO is cytochrome P450, which is involved in the oxidation of xenobiotics and endogenous compounds such as steroids, fatty acids, and vitamins.

MFOs can catalyze a variety of reactions, including hydroxylation, epoxidation, dealkylation, and deamination, among others. These reactions often lead to the activation or detoxification of xenobiotics, making MFOs an important component of the body's defense system against foreign substances. However, in some cases, these reactions can also produce reactive intermediates that may cause toxicity or contribute to the development of diseases such as cancer.

Endocannabinoids are naturally occurring compounds in the body that bind to cannabinoid receptors, which are found in various tissues and organs throughout the body. These compounds play a role in regulating many physiological processes, including appetite, mood, pain sensation, and memory. They are similar in structure to the active components of cannabis (marijuana), called phytocannabinoids, such as THC (tetrahydrocannabinol) and CBD (cannabidiol). However, endocannabinoids are produced by the body itself, whereas phytocannabinoids come from the cannabis plant. The two most well-known endocannabinoids are anandamide and 2-arachidonoylglycerol (2-AG).

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Oral administration is a route of giving medications or other substances by mouth. This can be in the form of tablets, capsules, liquids, pastes, or other forms that can be swallowed. Once ingested, the substance is absorbed through the gastrointestinal tract and enters the bloodstream to reach its intended target site in the body. Oral administration is a common and convenient route of medication delivery, but it may not be appropriate for all substances or in certain situations, such as when rapid onset of action is required or when the patient has difficulty swallowing.

The term "Area Under Curve" (AUC) is commonly used in the medical field, particularly in the analysis of diagnostic tests or pharmacokinetic studies. The AUC refers to the mathematical calculation of the area between a curve and the x-axis in a graph, typically representing a concentration-time profile.

In the context of diagnostic tests, the AUC is used to evaluate the performance of a test by measuring the entire two-dimensional area underneath the receiver operating characteristic (ROC) curve, which plots the true positive rate (sensitivity) against the false positive rate (1-specificity) at various threshold settings. The AUC ranges from 0 to 1, where a higher AUC indicates better test performance:

* An AUC of 0.5 suggests that the test is no better than chance.
* An AUC between 0.7 and 0.8 implies moderate accuracy.
* An AUC between 0.8 and 0.9 indicates high accuracy.
* An AUC greater than 0.9 signifies very high accuracy.

In pharmacokinetic studies, the AUC is used to assess drug exposure over time by calculating the area under a plasma concentration-time curve (AUC(0-t) or AUC(0-\∞)) following drug administration. This value can help determine dosing regimens and evaluate potential drug interactions:

* AUC(0-t): Represents the area under the plasma concentration-time curve from time zero to the last measurable concentration (t).
* AUC(0-\∞): Refers to the area under the plasma concentration-time curve from time zero to infinity, which estimates total drug exposure.

Tissue distribution, in the context of pharmacology and toxicology, refers to the way that a drug or xenobiotic (a chemical substance found within an organism that is not naturally produced by or expected to be present within that organism) is distributed throughout the body's tissues after administration. It describes how much of the drug or xenobiotic can be found in various tissues and organs, and is influenced by factors such as blood flow, lipid solubility, protein binding, and the permeability of cell membranes. Understanding tissue distribution is important for predicting the potential effects of a drug or toxin on different parts of the body, and for designing drugs with improved safety and efficacy profiles.

Forensic medicine, also known as legal medicine or medical jurisprudence, is a branch of medicine that deals with the application of medical knowledge to legal issues and questions. It involves the examination, interpretation, and analysis of medical evidence for use in courts of law. This may include determining the cause and manner of death, identifying injuries or diseases, assessing the effects of substances or treatments, and evaluating the competency or capacity of individuals. Forensic medicine is often used in criminal investigations and court cases, but it can also be applied to civil matters such as personal injury claims or medical malpractice suits.

"Swine" is a common term used to refer to even-toed ungulates of the family Suidae, including domestic pigs and wild boars. However, in a medical context, "swine" often appears in the phrase "swine flu," which is a strain of influenza virus that typically infects pigs but can also cause illness in humans. The 2009 H1N1 pandemic was caused by a new strain of swine-origin influenza A virus, which was commonly referred to as "swine flu." It's important to note that this virus is not transmitted through eating cooked pork products; it spreads from person to person, mainly through respiratory droplets produced when an infected person coughs or sneezes.

Cytochrome P-450 CYP3A is a subfamily of the cytochrome P-450 enzyme superfamily, which are primarily involved in drug metabolism in the human body. These enzymes are found predominantly in the liver, but also in other tissues such as the small intestine, kidneys, and brain.

CYP3A enzymes are responsible for metabolizing a wide variety of drugs, including many statins, benzodiazepines, antidepressants, and opioids. They can also metabolize endogenous compounds such as steroids and bile acids. The activity of CYP3A enzymes can be influenced by various factors, including genetic polymorphisms, age, sex, pregnancy, and the presence of other drugs or diseases.

The name "cytochrome P-450" refers to the fact that these enzymes contain a heme group that absorbs light at a wavelength of 450 nanometers when it is complexed with carbon monoxide. The term "CYP3A" denotes the specific subfamily of cytochrome P-450 enzymes that share a high degree of sequence similarity and function.

I am not aware of a widely accepted medical definition for the term "software," as it is more commonly used in the context of computer science and technology. Software refers to programs, data, and instructions that are used by computers to perform various tasks. It does not have direct relevance to medical fields such as anatomy, physiology, or clinical practice. If you have any questions related to medicine or healthcare, I would be happy to try to help with those instead!

Deuterium exchange measurement is a technique used in physical chemistry and biochemistry to study the structure, dynamics, and interactions of proteins, peptides, and other biological macromolecules. This method involves the exchange of deuterium (a heavy isotope of hydrogen) for hydrogen atoms in the molecule of interest.

The process typically begins with the preparation of a sample containing the macromolecule, which is then exposed to an environment with a high concentration of deuterated solvent, such as heavy water (D2O). Over time, some or all of the exchangeable hydrogen atoms in the molecule will be replaced by deuterium atoms through a series of chemical reactions.

The rate and extent of this deuterium exchange can provide valuable information about various aspects of the macromolecule's structure and behavior, including:

1. Solvent accessibility: Regions of the molecule that are exposed to solvent will typically undergo faster deuterium exchange than those that are buried within the protein's core or shielded by other structures. This allows researchers to identify which parts of the molecule are accessible to the solvent and infer information about its overall shape and conformation.
2. Dynamics: The rate of deuterium exchange can also be used to study the flexibility and dynamics of different regions of the macromolecule. Flexible or disordered regions will typically exhibit faster exchange rates than more rigid or structured ones, providing insights into the molecule's internal motions and conformational changes.
3. Interactions: Deuterium exchange measurements can also be used to study how the macromolecule interacts with other molecules, such as ligands, drugs, or other proteins. By comparing the deuterium exchange patterns in the presence and absence of these interaction partners, researchers can identify which regions of the molecule are involved in binding and learn more about the nature of these interactions.

There are several experimental methods for measuring deuterium exchange, including nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), and infrared spectroscopy (IR). Each method has its advantages and limitations, but all provide valuable information that can help researchers better understand the structure, dynamics, and function of biological macromolecules.

Proteins are complex, large molecules that play critical roles in the body's functions. They are made up of amino acids, which are organic compounds that are the building blocks of proteins. Proteins are required for the structure, function, and regulation of the body's tissues and organs. They are essential for the growth, repair, and maintenance of body tissues, and they play a crucial role in many biological processes, including metabolism, immune response, and cellular signaling. Proteins can be classified into different types based on their structure and function, such as enzymes, hormones, antibodies, and structural proteins. They are found in various foods, especially animal-derived products like meat, dairy, and eggs, as well as plant-based sources like beans, nuts, and grains.

Aryl hydrocarbon hydroxylases (AHH) are a group of enzymes that play a crucial role in the metabolism of various aromatic and heterocyclic compounds, including potentially harmful substances such as polycyclic aromatic hydrocarbons (PAHs) and dioxins. These enzymes are primarily located in the endoplasmic reticulum of cells, particularly in the liver, but can also be found in other tissues.

The AHH enzymes catalyze the addition of a hydroxyl group (-OH) to the aromatic ring structure of these compounds, which is the first step in their biotransformation and eventual elimination from the body. This process can sometimes lead to the formation of metabolites that are more reactive and potentially toxic than the original compound. Therefore, the overall impact of AHH enzymes on human health is complex and depends on various factors, including the specific compounds being metabolized and individual genetic differences in enzyme activity.

I'm sorry for any confusion, but "Polyunsaturated Alkamides" is not a widely recognized medical term or concept. It seems to be a combination of two different terms: "polyunsaturated" which relates to fatty acid chemistry, and "alkamides" which are a type of compound found in certain plants.

1. Polyunsaturated: This term refers to fatty acids that have multiple double bonds in their carbon chain. These fatty acids are essential to the human diet and are commonly found in foods like fish, nuts, and seeds. They are often referred to as Omega-3 or Omega-6 fatty acids.

2. Alkamides: These are a type of compound found in some plants, including Echinacea species. They have been studied for their potential biological activities, such as anti-inflammatory and immunomodulatory effects.

Without more context, it's difficult to provide a precise definition or medical interpretation of "Polyunsaturated Alkamides." If you have more information about how these terms are being used together, I'd be happy to try to provide a more specific answer.

Capillary electrophoresis-mass spectrometry Ion-mobility spectrometry-mass spectrometry Liquid chromatography-mass spectrometry ... Gas chromatography-mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass ... "Gas chromatography-mass spectrometry with supersonic molecular beams". Journal of Mass Spectrometry. 43 (2): 141-63. Bibcode: ... Gas Chromatography and Mass Spectrometry: A Practical Guide. Academic Press. ISBN 978-0-08-092015-3. Jones M. "Gas ...
"Hyphenation of aqueous liquid chromatography to pyrolysis-gas chromatography and mass spectrometry for the comprehensive ... Pyrolysis-gas chromatography-mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition ... "Derivatization in mass spectrometry --7. On-line derivatisation/degradation". European Journal of Mass Spectrometry. 12 (1): 1- ... to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. Pyrolysis is the ...
Gas chromatography-mass spectrometry Capillary electrophoresis-mass spectrometry Ion-mobility spectrometry-mass spectrometry de ... "Combined liquid chromatography mass spectrometry. Part I. Coupling by means of a moving belt interface". Mass Spectrometry ... "Combined liquid chromatography mass spectrometry. Part III. Applications of thermospray". Mass Spectrometry Reviews. 11 (1): 3- ... Mass Spectrom. 7: 858. Baldwin, M. A.; McLafferty, F. W. (1973). "Liquid chromatography-mass spectrometry interface-I: The ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. Poole, Colin; Jennings, Walter (2012 ... Others introduced mass spectrometers to gas chromatography in the late 1950s. The work of Martin and Synge also set the stage ... "Milestones in the Development of Gas Chromatography". Gas Chromatography. Elsevier. p. 2. ISBN 9780123855404. Lesney, Mark S. ( ... Martin, in collaboration with Anthony T. James, went on to develop gas chromatography (GC; the principles of which Martin and ...
"Early Gas Chromatography/Mass Spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-371. doi:10.1016 ... These include high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, ... "Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. Gohlke, Roland S.; McLafferty, Fred W ... the most important advancements in forensic chemistry came in 1955 with the invention of gas chromatography-mass spectrometry ( ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. "1929: Bendix Building, 1206 South ... Harrington of Bendix Aviation in the 1950s led to the combination of gas chromatography and mass spectrometry, and the ... development of Gas chromatography-mass spectrometry instrumentation. Beginning in the 1960s, Bendix produced scientific ... Criteria were met for hostile and non-hostile environments that provided seals against liquids and gasses. In 1971, Bendix ...
Gohlke, R. S.; McLafferty, F. W. (1993). "Early gas chromatography/mass spectrometry". J. Am. Soc. Mass Spectrom. 4 (5): 367- ... "Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. Gohlke, R. S. (1959). "Time-of-Flight ... 1959 Researchers at Dow Chemical interface a gas chromatograph to a mass spectrometer. 1964 British Mass Spectrometry Society ... History of Mass Spectrometry - Pioneers - University of New South Wales Sydney Five Mass Spectrometry Nobel Prize Pioneers - ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 Nov 2019. National Historic Chemical Landmarks ( ... in Chemistry Steroid Medicines and Upjohn Innovation Gas Chromatography-Mass Spectrometry, Midland, Michigan Mann, Benjamin W ... now owned by the Massachusetts Institute of Technology) in Cambridge, Massachusetts. The discovery and isolation of phytochrome ... "Neil Bartlett and Reactive Noble Gases". National Historic Chemical Landmarks. American Chemical Society. Archived from the ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Archived from the original on April 6, 2020. Retrieved ... was an American pioneer in the development of gas chromatography-mass spectrometry equipment (GC/MS). Finnigan founded the ... An EPA manual for organic analysis using gas chromatography - mass spectrometry. Environmental Protection Agency. pp. 2, 4. ... The Encyclopedia of Mass Spectrometry Volume 9: Historical Perspectives, Part B: Notable People in Mass Spectrometry. Elsevier ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 November 2019. D.Sc, F. W. Aston M. A. (1 ... KM Downard (2007). "Francis William Aston - the man behind the mass spectrograph". European Journal of Mass Spectrometry. 13 (3 ... 12 December 1922 Mass Spectra and Isotopes Aston biography from Cambridge History of Mass Spectrometry - Pioneers (CS1: Julian- ... The British Mass Spectrometry Society awards the Aston Medal in his honour. "Francis W. Aston - Biographical". NobelPrize.org. ...
ISBN 978-1-60774-172-5. Linskens, Hans-Ferdinand; Jackson, John F. (2012-12-06). Gas Chromatography/Mass Spectrometry. Springer ...
"Gas Chromatography and Mass Spectrometry". In Sparkman, O. D., Penton, Z. E., Kitson, F. G. (eds.). Gas Chromatography (2nd ed ... This is achieved using Gas Chromatography-Mass Spectrometry (GC-MS) alongside other methods, including isotope ratio mass ... of organic residues of archaeological origin by high-temperature gas chromatography and gas chromatography-mass spectrometry". ... Reber, Eleanora A. (2018), "Gas Chromatography-Mass Spectrometry (GC-MS): Applications in Archaeology", in Smith, Claire (ed ...
"Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-71. doi:10.1016/ ... "Time-of-Flight Mass Spectrometry and Gas-Liquid Partition Chromatography". Analytical Chemistry. 31 (4): 535-541. doi:10.1021/ ...
"Early gas chromatography/mass spectrometry". Journal of the American Society for Mass Spectrometry. 4 (5): 367-371. doi:10.1016 ... Mass chromatogram Mass spectral interpretation Mass spectrum analysis Tandem mass spectrometry McLafferty FW (1 January 1993). ... Principles and application of electron-based dissociation in mass spectrometry-based analysis of protein structure" (PDF). Mass ... Tandem mass spectrometry-generated fragmentation is typically made in the collision zone (post-source fragmentation) of a ...
Using gas chromatography and mass spectrometry. (E,E) 9,12-octadecadienoic acid, methyl ester, 9-Octadecenoic acid(Z)-,methyl ...
... gas chromatography - mass spectrometry; ICP-MS, inductively coupled plasma - mass spectrometry; CO, carbon monoxide, VOC, ... ultra-performance liquid chromatography-mass spectrometry; HPLC-DAD-MMI-MS, high performance liquid chromatography-diode array ... Abbreviations: TSNA, tobacco specific nitrosoamines; LC-MS, liquid chromatography-mass spectrometry; MAO-A and B, ... In physics, a vapor is a substance in the gas phase whereas an aerosol is a suspension of tiny particles of liquid, solid or ...
ISBN 0-909605-69-6. "GCMS - Gas Chromatography Mass Spectrometry Analysis" (PDF). New Direction Aromatics. Archived (PDF) from ...
Gas Chromatography, Infrared Spectrometry or Mass Spectrometry is used in combination with the color test to identify the type ... Lehrer M (December 1998). "The role of gas chromatography/mass spectrometry. Instrumental techniques in forensic urine drug ... Sípoli Marques MA, Pinto Damasceno LM, Gualberto Pereira HM, Caldeira CM, Pereira Dias BF, de Giacomo Vargens D, et al. (May ... and identifying human remains of victims from mass disasters or missing person cases. It is also used to link suspects or ...
Gas chromatography (GC), especially when interfaced with mass spectrometry (GC-MS), is a widely used separation technique for ... "Gas Chromatography Mass Spectrometry (GC-MS) Information". Thermo Fisher Scientific - US. Retrieved 2018-09-26. Gika HG, ... in 1971 after they demonstrated that gas chromatography-mass spectrometry (GC-MS) could be used to measure compounds present in ... Dettmer K, Aronov PA, Hammock BD (2007). "Mass spectrometry-based metabolomics". Mass Spectrometry Reviews. 26 (1): 51-78. ...
Gas chromatography-mass spectrometry (MGAK) for atmospheric analysis. Developed by Russia. Power source The science and ... The payload mass is about 45 kg and consists of the following instruments (plus an instrument interface and memory unit (BIP ...
Garcia, Antonia; Barbas, Coral (2011). Metz, Thomas O. (ed.). Gas chromatography-mass spectrometry (GC-MS)-based metabolomics. ... A Study via Mass Spectrometry and NMR Spectroscopy". Analytical Chemistry. 92 (19): 12891-12899. doi:10.1021/acs.analchem. ... "Quality assurance procedures for mass spectrometry untargeted metabolomics. a review". Journal of Pharmaceutical and Biomedical ... Journal of Chromatography A. 1032 (1): 299-304. doi:10.1016/j.chroma.2003.09.028. hdl:10637/1056. ISSN 0021-9673. PMID 15065808 ...
"Plasma hydroxyurea determined by gas chromatography-mass spectrometry". Journal of Chromatography. B, Analytical Technologies ...
... using gas chromatography-mass spectrometry and trimethylsilyl derivatives". Industrial Crops and Products. 108: 36-43. doi: ... The remaining waxy mass is known as a concrete. The concrete is then mixed with alcohol which dissolves the aromatic ... Because CO 2 is gas at normal atmospheric pressure, it leaves no trace of itself in the final product. The equipment for CO 2 ... Under normal pressure CO 2 changes directly from a solid to a gas in a process known as sublimation.) The supercritical fluid ...
These included mass spectrometry and gas chromatography instruments. They have since divested these products to Scion ... laboratory gas chromatography (GC), and GC-triple quadrupole mass spectrometer (originally designed by Bear Instruments and ... Later, the company would expand their product range with MRI, FTIR and FT-Raman spectrometers and with mass spectrometers. In ... It is headquartered in Billerica, Massachusetts, and is the publicly traded parent company of Bruker Scientific Instruments ( ...
"Gas Chromatography-Mass Spectrometry". American Chemical Society. Retrieved 19 November 2019. "J.J. Thomson - Biographical". ... In 1991, the thomson (symbol: Th) was proposed as a unit to measure mass-to-charge ratio in mass spectrometry in his honour. J ... Thomson's separation of neon isotopes by their mass was the first example of mass spectrometry, which was subsequently improved ... were the first use of mass spectrometry and led to the development of the mass spectrograph. Thomson was awarded the 1906 Nobel ...
Gas or liquid chromatography and mass spectrometry (e.g. LC-MS/MS) achieves greater specificity than immunoassays. Measurement ...
Sterol levels are measured by gas chromatography-mass spectrometry. Genetic screening for Conradi-Hünermann syndrome via the ...
Analysis using gas chromatography and mass spectrometry has been used to identify bioactive compounds in essential oils. These ... Adams, Robert P. (2007). Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry. Barrett, S. " ... ISBN 0-12-227055-X.[page needed] Cather, JC; MacKnet, MR; Menter, MA (2000). "Hyperpigmented macules and streaks". Proceedings ...
They used gas chromatography and gas chromatography/mass spectrometry methods. It was found that the flowers of Iris kerneriana ...
"Cinnamaldehyde content in foods determined by gas chromatography-mass spectrometry". Journal of Agricultural and Food Chemistry ... Ma, W.-B.; Feng, J.-T.; Jiang, Z.-L.; Zhang, X. (2014). "Fumigant Activity of 6 Selected Essential Oil Compounds and Combined ...
Capillary electrophoresis-mass spectrometry Ion-mobility spectrometry-mass spectrometry Liquid chromatography-mass spectrometry ... Gas chromatography-mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass ... "Gas chromatography-mass spectrometry with supersonic molecular beams". Journal of Mass Spectrometry. 43 (2): 141-63. Bibcode: ... Gas Chromatography and Mass Spectrometry: A Practical Guide. Academic Press. ISBN 978-0-08-092015-3. Jones M. "Gas ...
... is a method that combines the features of gas-liquid chromatography and mass ... The GC-MS is composed of two major building blocks: the gas chromatograph and the mass spectrometer. The gas chromatograph ... The most common type of mass spectrometer (MS) associated with a gas chromatograph (GC) is the quadrupole mass spectrometer, ... The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass ...
Detection of leachables and cytotoxicity after exposure to methacrylate- and epoxy-based root canal sealers in vitro. Greta Lodienè, Hilde M. Kopperud, Dag Ørstavik and Ellen Bruzell , June 19th 2013. - Abstract Root canal sealing materials may have toxic potential in vitro depending on the cell line, cytotoxicity assay, material chemistry, and degree of polymer curing. The aims of the present study were to detect leaching components from epoxy- or methacrylate-based root canal sealers and to investigate the degree of cytotoxicity after exposure to extracts from […]. ...
Fast determination of volatile components in rhizoma curcuma by headspace gas chromatography-mass spectrometry]. Download Prime ... CurcumaGas Chromatography-Mass SpectrometryOils, VolatilePlant OilsPlants, MedicinalRhizomeSolventsSteamTechnology, ... Fast Determination of Volatile Components in Rhizoma Curcuma By Headspace Gas Chromatography-mass Spectrometry]. Zhong Yao Cai. ... Fast determination of volatile components in rhizoma curcuma by headspace gas chromatography-mass spectrometry]. Zhong Yao Cai ...
This paper outlines a six-step, data-driven, framework to develop and evaluate gas chromatography mass spectrometry (GC-MS) ... A framework for the development of targeted gas chromatography mass spectrometry (GC-MS) methods: Synthetic cannabinoids. ... The targeted method successfully differentiated 50 cannabinoids based on either retention time differences or mass spectral ...
The Detection of Diamondoid Compounds in Ignitable Liquid Residues by Gas Chromatography/Mass Spectrometry, Part II. Presenting ...
High-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and gas chromatography-flame ... High-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and gas chromatography-flame ... "High-performance Liquid Chromatography-atmospheric Pressure Chemical Ionization Mass Spectrometry and Gas Chromatography-flame ... High-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and gas chromatography-flame ...
The Analysis of the Fatty Acid Content of Fingerprint Residues Using Gas Chromatography/Mass Spectrometry (GC/MS). Presenting ...
Gas chromatography-mass spectrometry (GC-MS) analysis of aqueous extract of Daniellia oliveri Stem Bark. Pharm. Acta, Vol.8.. ... Phytochemical Analysis of Flower extracts of Different Cassia Species by Using Gas Chromatography-Mass Spectrometry table, th, ... Phytochemical Analysis of Flower extracts of Different Cassia Species by Using Gas Chromatography-Mass Spectrometry. ... Cassia fistula and Cassia occidentalis by using gas chromatography-mass spectrometry (GC-MS). Materials and Methods: The GC-MS ...
Analysis of Oak Volatiles by Gas Chromatography-Mass Spectrometry after Ozone Sanitization Steven D. Marko, Erin S. Dormedy, ... Analysis of Oak Volatiles by Gas Chromatography-Mass Spectrometry after Ozone Sanitization Steven D. Marko, Erin S. Dormedy, ... Analysis of Oak Volatiles by Gas Chromatography-Mass Spectrometry after Ozone Sanitization. Steven D. Marko, Erin S. Dormedy, ... Analysis of Oak Volatiles by Gas Chromatography-Mass Spectrometry after Ozone Sanitization ...
Detection of cobalamin deficiency using the urinary methylmalonic acid test by gas chromatography mass spectrometry. ... Detection of cobalamin deficiency using the urinary methylmalonic acid test by gas chromatography mass spectrometry. ...
... iv by gas chromatography-mass spectrometry with multiple detection method. ...
Analysis of Residual Pesticides in Hemp Oil Extract by Direct Liquid Injection Gas Chromatography/Mass Spectrometry. Abstract. ... for the analysis of pesticide residues in hemp oil samples by direct liquid injection gas chromatography/mass spectrometry (GC/ ... robotic with automated liquid option for the analysis of pesticide residues in hemp oil samples by direct liquid injection gas ...
Using an integrated platform of metabolic labeling, high-resolution mass spectrometry and computational analysis, we report ... Gas chromatography-mass spectrometry. To measure the rate and level of label enrichment in the animals, we performed gas ... Liquid chromatography-tandem mass spectrometry. We analyzed the peptide samples by liquid chromatography-tandem mass ... Measurement of human plasma proteome dynamics with (2)H(2)O and liquid chromatography tandem mass spectrometry. Anal. Biochem. ...
Title: Position‐specific carbon isotope analysis of serine by gas chromatography/Orbitrap mass spectrometry, and an application ... Accepted Manuscript: Position‐specific carbon isotope analysis of serine by gas chromatography/Orbitrap mass spectrometry, and ... specific carbon isotope analysis of serine by gas chromatography/Orbitrap mass spectrometry, and an application to plant ... specific carbon isotope analysis of serine by gas chromatography/Orbitrap mass spectrometry, and an application to plant ...
... utilizes Gas chromatography (GC) to separate a chemical mixture into individual ... Gas Chromatography utilizes the principle that intermolecular (physical adsorption) forces between molecules in a gas [&hellip ... molecules followed by Mass spectrometry (MS) to identify the molecules. These two distinct micro-analytical techniques are ... Gas Chromatography-Mass Spectrometry (GC-MS) Laboratories and Testing Services in California, USA: Infinita Lab is provides Gas ...
... utilises pyrolysis gas chromatography-mass spectrometry (GC-MS) with the aim to identify organic molecules in Martian sub- ... including four gas chromatography-mass spectrometry columns and a Raman spectrometer. Featuring chemical equipment found within ... appears that the question of life on Mars could be resolved in a matter of years thanks to gas chromatography mass spectrometry ... out more in regards to Gas Chromatography and what Apexs Nitrogen Generators can do in regards to your Gas Chromatography ...
... ... Calibration Gas Chromatography-Mass Spectrometry Ions Limit Of Detection Nitrobenzenes Particulate Matter Reproducibility Of ... Sensitive and selective gas chromatography-tandem mass spectrometry method for the detection of nitrobenzene in tobacco smoke ... "Sensitive and selective gas chromatography-tandem mass spectrometry method for the detection of nitrobenzene in tobacco smoke" ...
All analyses were conducted on a Gas Chromatography-Mass Spectrometry (GC-MS)-Olfactometry system where the human nose is used ... The abundance of specific gases and odor was amplified when plates collected PM. The results of this research indicate that PM ... odor-causing gases are often present at very low concentrations in a complex matrix of less important or irrelevant gases. The ... on the abundance of specific gases, odor intensity, and odor character were tested. Steel plates were effectively able to ...
Separation and identification of phenol-formaldehyde condensates by gas chromatography-mass spectrometry II. Base-catalysed ... Separation and identification of phenol-formaldehyde condensates by gas chromatography-mass spectrometry II. Base-catalysed ...
Chromatography *Chromatography and Mass Spectrometry Reagents*Gas Chromatography Derivatization Reagents*Silylation Grade ...
Identification of stigmasterol by preparative thin-layer chromatography, infrared, gas chromatography†...
... pesticides screening in multiple commodities using headspace-solid phase microextraction-gas chromatography-mass spectrometry. ... pesticides screening in multiple commodities using headspace-solid phase microextraction-gas chromatography-mass spectrometry ...
Craston, James (2017) Considering the use of Gas Chromatography-Mass Spectrometry (GC-MS) in Inferring the Relationship Between ... Through the use of Gas Chromatography-Mass Spectrometry (GC-MS) of 27 mummified animal remains (supplied by Buckley & Tunney ... Considering the use of Gas Chromatography-Mass Spectrometry (GC-MS) in Inferring the Relationship Between Long-Distance Trade ... Filename: James Craston MA by Research.pdf Licence: This work is licensed under a Creative Commons Attribution-NonCommercial- ...
Current Practice of Gas Chromatography-Mass Spectrometry Wilfried M.A. Niessen SPECIAL INDIAN REPRINT ! April 4, 2001 by CRC ... Current Practice of Gas Chromatography-Mass Spectrometry Wilfried M.A. Niessen Special Indian Reprint. ... This volume details the principles and instrumentation of gas chromatography-mass spectrometry (CG-MS), and outlines industrial ... Current Practice of Gas Chromatography-Mass Spectrometry. Wilfried M.A. Niessen. SPECIAL INDIAN REPRINT ! ...
... as the hemolymph of mature female and male abalones using ultrahigh-performance liquid chromatography-tandem mass spectrometry ... The lipid profiles of two abalone species have been determined using gas chromatography-mass spectrometry (GC-MS) [13]. In ... T. Cajka and O. Fiehn, "Comprehensive analysis of lipids in biological systems by liquid chromatography-mass spectrometry," ... The HESI parameters were set as follows: sheath gas flow rate, 5 arb; auxiliary gas flow rate, 5 arb; sweep gas flow rate, 0; ...
Liquid Chromatography (HPLC, UHPLC, LCxLC), Mass Spectrometry (GC-MS, LC-MS, ICP-MS, MALDI-TOF), Spectroscopy (FTIR, UV-Vis, AA ... Anthias Consulting is the worlds leading independent authority on Analytical Techniques including Gas Chromatography (GC, ... A Molecules Journey Through Gas Chromatography : Download a copy of the presentation. ... Current Detector Options in Gas Chromatography : Download a copy of the presentation. ...
Fatty acid composition of the extract was identified by gas chromatography-mass spectrometry with their relative concentrations ... Fatty acids analysis of Ficus religiosa stem bark by gas chromatography-mass spectrometry ...
GAS CHROMATOGRAPHY, MASS SPECTROMETRY Less expensive, fast, easy to use More expensive, labor intensive Most frequently used ... providers office, and laboratory-based gas or liquid chromatography/mass spectrometry. See the chart below for a description ...
... followed by gas chromatography-mass spectrometry (GC-MS) ... followed by gas chromatography-mass spectrometry (GC-MS). ... followed by gas chromatography-mass spectrometry (GC‑MS). The limit of determination depends on the matrix, on the specific ... compound to be analysed and on the sensitivity of the mass spectrometer. For most plant treatment agents and biocides to which ...
  • ISO 27108:2010 specifies a method for the determination of the dissolved amount of selected plant treatment agents and biocide products in drinking water, ground water and surface water by solid‑phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC‑MS). The limit of determination depends on the matrix, on the specific compound to be analysed and on the sensitivity of the mass spectrometer. (iso.org)
  • Discrimination rancidity degree of infant formula rice flour based on Headspace Solid-Phase Microextraction combined with Gas Chromatography-Mass Spectrometry as an alternative to sensory evaluation. (bvsalud.org)
  • To mitigating the serious threat of harmful volatile substances to the health of infants , an alternative method of odor evaluation were proposed based on Headspace solid-phase microextraction (HS-SPME) combined with Gas Chromatography-Mass Spectrometry (GC-MS) to discriminate the degree of rancidity of infant formula rice flour (IFRF). (bvsalud.org)
  • Conifer seed oils from European Larch (Larix decidua), Norway Spruce (Picea abies) and European Silver Fir (Abies alba) have been analyzed by non-aqueous reversed-phase high-performance liquid chromatography (NARP-HPLC) with atmospheric pressure chemical ionisation (APCI)-MS detection. (unboundmedicine.com)
  • Using the honey bee as a model, we directly compare the leading current methods of using High Performance Liquid Chromatography (HPLC) with an evaporative light-scattering detector and Gas Chromatography coupled with Mass Spectrometry (GC-MS) to determine which method would be better for measuring trehalose, glucose, and fructose in terms of reproducibility, accuracy, and sensitivity. (sabanciuniv.edu)
  • Like liquid chromatography-mass spectrometry, it allows analysis and detection even of tiny amounts of a substance. (wikipedia.org)
  • Detection of cobalamin deficiency using the urinary methylmalonic acid test by gas chromatography mass spectrometry. (bmj.com)
  • To improve the accuracy of chemical molecule structure analysis, Gas Chromatography-Mass Spectrometry (GC-MS) combines the functions of Gas Chromatography (GC) and Mass Spectrometry (MS). Drug detection, fire investigati on, environmental analysis, investigating explosives, and identifying unidentified materials are some applications of GC-MS. Utilizing its extensive network of laboratories, Infinita Lab, USA, provides this test to its clients in the USA and other locations. (infinitalab.com)
  • The analysis of Pelargonium graveolens essential oil is reported using comprehensive two-dimensional gas chromatography with quadrupole mass spectrometric detection (GC×GC-qMS). (edu.au)
  • Detection and quantification of amyloid β protein and variants by immunoprecipitation-mass spectrometry. (eanso.org)
  • The potential of pyrolysis gas chromatography-mass spectrometry (Py-GCMS ) as a tool for the estimation of post-mortem age of bones has been investigated. (uc.pt)
  • Therefore, when an identifying mass spectrum appears at a characteristic retention time in a GC-MS analysis, it typically increases certainty that the analyte of interest is in the sample. (wikipedia.org)
  • The GC-MS analysis of flower extracts was performed using a GC and MS JEOL GC mate system and Interpretation on mass spectrum GC-MS was conducted using the database of National Institute Standard and Technology (NIST). (scialert.net)
  • This study describes the use of the GERSTEL MPS robotic with automated liquid option for the analysis of pesticide residues in hemp oil samples by direct liquid injection gas The number of cannabis containing products, such as extracts, tinctures, edibles, waxes and oils, available in the United States have increased significantly due to changes in state law and the 2018 Farm Bill. (gerstelus.com)
  • This study describes the use of the GERSTEL MPS robotic with automated liquid option for the analysis of pesticide residues in hemp oil samples by direct liquid injection gas chromatography/mass spectrometry (GC/MS). This technique is sensitive, accurate and precise and allows the quantification of pesticides of interest well below the established limits of quantification for the State of California. (gerstelus.com)
  • Using an integrated platform of metabolic labeling, high-resolution mass spectrometry and computational analysis, we report here a comprehensive dataset of the in vivo half-life of 3,228 and the expression of 8,064 cardiac proteins, quantified under healthy and hypertrophic conditions across six mouse genetic strains commonly employed in biomedical research. (nature.com)
  • The sample analysis at the Mars instrument suite takes up more than half of the science payload onboard the Mars Science Laboratory Rover and to facilitate its mission, the Franklin rover will be carrying 26kg of scientific equipment, including four gas chromatography-mass spectrometry columns and a Raman spectrometer. (apexgasgenerators.com)
  • All analyses were conducted on a Gas Chromatography-Mass Spectrometry (GC-MS)-Olfactometry system where the human nose is used as a detector simultaneously with chemical analysis via MS. The effects of sampling time, distance from a source, and the presence of particulate matter (PM) on the abundance of specific gases, odor intensity, and odor character were tested. (iastate.edu)
  • Identification of stigmasterol by preparative thin-layer chromatography, infrared, gas chromatographyâ€"mass spectrometry analysis, and antioxidant properties of Cenchrus ciliaris L. (greenpharmacy.info)
  • Gas Chromatography-Mass Spectrometry Analysis of Photosensitive Characteristics in Citrus and Herb Essential Oils. (eanso.org)
  • Recently, we introduced a heated nebulizer microchip and showed its potential to interface liquid microseparation techniques and GC with API-MS. This study demonstrates the feasibility of GC-microchip atmospheric pressure photoionization-tandem mass spectrometry (GC-μAPPI-MS/MS) in the analysis of underivatized anabolic steroids in urine. (aalto.fi)
  • Since cyanide forms volatile hydrogen cyanide gas, tissue sampling techniques, storage, and cyanide analysis must be done with caution. (cdc.gov)
  • Mass Spectrometry works by ionizing chemical compounds to generate charged ions, with a range of molecular masses. (infinitalab.com)
  • Individual compounds have their own unique mass spectrum since every pure compound always produces the same family of ions. (infinitalab.com)
  • Gas chromatography coupled with mass spectrometry (GC-MS) was used to analyze for phytochemicals and bioactive compounds in three species of Apocynacae, Gongronema latifolium , Vincetoxicum rossicum and Marsdenia edulis commonly found in tropical rainforest vegetation and used as food and traditional medicine by locals. (phcogj.com)
  • The Franklin rover, named after the DNA double-helix co-discoverer Rosalind Franklin, utilises pyrolysis gas chromatography-mass spectrometry (GC-MS) with the aim to identify organic molecules in Martian sub-surface materials. (apexgasgenerators.com)
  • The first on-line coupling of gas chromatography to a mass spectrometer was reported in the late 1950s. (wikipedia.org)
  • In 1964, Electronic Associates, Inc. (EAI), a leading U.S. supplier of analog computers, began development of a computer controlled quadrupole mass spectrometer under the direction of Robert E. Finnigan. (wikipedia.org)
  • The GC-MS is composed of two major building blocks: the gas chromatograph and the mass spectrometer. (wikipedia.org)
  • The molecules are retained by the column and then elute (come off) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. (wikipedia.org)
  • The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass-to-charge ratio. (wikipedia.org)
  • Sometimes two different molecules can also have a similar pattern of ionized fragments in a mass spectrometer (mass spectrum). (wikipedia.org)
  • Combining the two processes reduces the possibility of error, as it is extremely unlikely that two different molecules will behave in the same way in both a gas chromatograph and a mass spectrometer. (wikipedia.org)
  • The molecules take different amounts of time (called the retention time) to come out of (elute from) the gas chromatograph, and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. (iitk.ac.in)
  • The most common type of mass spectrometer (MS) associated with a gas chromatograph (GC) is the quadrupole mass spectrometer, sometimes referred to by the Hewlett-Packard (now Agilent) trade name "Mass Selective Detector" (MSD). (iitk.ac.in)
  • Another relatively common detector is the ion trap mass spectrometer. (iitk.ac.in)
  • A suite of three instruments, including a Mass Spectrometer, Gas Chromatograph, and Tunable laser spectrometer this rover also scans and measures for the profusions of other light elements which are correlated with life, such as hydrogen, oxygen, and nitrogen. (apexgasgenerators.com)
  • Using GC and Mass Spec, MOMA blends a tiny gas chromatograph and mass spectrometer with an oven and laser. (apexgasgenerators.com)
  • Photographed in 2012, chemist Jennifer Roberts, of the Chemical Exposure & Monitoring Branch of the Division of Applied Research and Technology (DART), was performing a manual injection on a gas chromatograph-mass spectrometer (GC-MS), while inside the Gas Chromatography-Mass Spectrometry Lab, in Cincinnati, Ohio. (cdc.gov)
  • The abundance of specific gases and odor was amplified when plates collected PM. The results of this research indicate that PM is major carrier of odor and several key swine odorants. (iastate.edu)
  • The mass spectrometry process normally requires a very pure sample while gas chromatography using a traditional detector (e.g. (wikipedia.org)
  • The gas chromatograph utilizes a capillary column whose properties regarding molecule separation depend on the column's dimensions (length, diameter, film thickness) as well as the phase properties (e.g. 5% phenyl polysiloxane). (wikipedia.org)
  • In a gas chromatograph, the sample chemical mixture is vaporized in an oven and transported by an inert carrier gas into a column (packed or capillary), containing the solid phase (termed stationary phase). (infinitalab.com)
  • In present study, an effort is given to utilize gas chromatography-mass spectroscopy to obtain PAHs profile that could help forensic scientist in selection of evidence at the scene of fire. (asianpubs.org)
  • The targeted method successfully differentiated 50 cannabinoids based on either retention time differences or mass spectral dissimilarity - determined using a newly developed spectral comparison test. (ojp.gov)
  • In contrast to steady-state protein abundance, which may be quantified directly in mass spectrometry (MS) by spectral intensity 16 , 17 or sampling frequency 18 , 19 , protein turnover rates cannot be predicted from steady-state data 20 , requiring instead methods that can distinguish old and new protein molecules in mass spectra 11 , 21 . (nature.com)
  • A spectral acquisition rate of 20 Hz was achieved by using a reduced mass scan range of 188 u. 65 components were identified within the two-dimensional separation space based upon retention index and mass spectral matching with literature data. (edu.au)
  • Mass spectrometers equipped with atmospheric pressure ion sources (API-MS) have been designed to be interfaced with liquid chromatographs (LC) and have rarely been connected to gas chromatographs (GC). (aalto.fi)
  • There are two main types of UDTs-- immunoassay drug testing conducted at a laboratory or at the point of care in a provider's office, and laboratory-based gas or liquid chromatography/mass spectrometry. (cdc.gov)
  • Therefore, in the present study, we performed untargeted lipid profiling of abalone tissues at different developmental stages as well as the hemolymph of mature female and male abalones using ultrahigh-performance liquid chromatography-tandem mass spectrometry. (hindawi.com)
  • Serum metabolites were quantified by using gas chromatography-mass spectrometry and ultrahigh performance liquid chromatography-mass spectrometry. (nih.gov)
  • Plasma cortisol was measured by liquid chromatography. (lu.se)
  • Gas Chromatography-Mass Spectrometry (GC-MS) utilizes Gas chromatography (GC) to separate a chemical mixture into individual molecules followed by Mass spectrometry (MS) to identify the molecules. (infinitalab.com)
  • Gas Chromatography utilizes the principle that intermolecular (physical adsorption) forces between molecules in a gas and a solid surface depend upon the molecular structure and the nature of the solid surface. (infinitalab.com)
  • We propose the addition of a labelled internal standards to nullify the effect of variable humidity on the analytical performance of needle trap micro-extraction combined with gas chromatography mass spectrometry. (unipi.it)
  • Polycyclic aromatic hydrocarbons (PAHs) profile by gas-chromatography-mass spectrometry were recently used for the identification of sources of contamination in environmental forensic investigations. (asianpubs.org)
  • Mass Spectrometers can work in both full scan and selective ion monitoring (SIM) modes. (infinitalab.com)
  • This method is applicable to the determination of the sum of SCCPs in unfiltered surface water, ground water, drinking water and waste water using gas chromatography-mass spectrometry with electron capture negative ionization (GC-ECNI-MS). (iso.org)
  • TGs containing Delta5-UPIFAs have a higher retention in comparison with common TGs found in plant oils with single methylene interrupted Delta6(9)-FAs and also significantly changed relative abundances of fragment ions in APCI mass spectra. (unboundmedicine.com)
  • The ions are then accelerated in an electric field and separated in vacuum, depending on their mass as well as their charge. (infinitalab.com)
  • The separated ions are analyzed by spectrometry principles. (infinitalab.com)
  • Journal of Chromatography. (unboundmedicine.com)
  • AU - Lísa,Miroslav, AU - Holcapek,Michal, AU - Rezanka,Tomás, AU - Kabátová,Nadezda, Y1 - 2007/02/06/ PY - 2006/09/04/received PY - 2007/01/23/revised PY - 2007/01/25/accepted PY - 2007/2/20/pubmed PY - 2007/5/1/medline PY - 2007/2/20/entrez SP - 67 EP - 77 JF - Journal of chromatography. (unboundmedicine.com)
  • Journal of Chromatography & Separation Techniques, 06(01). (eanso.org)
  • JOURNAL OF CHROMATOGRAPHY A , 1217 (52), 8290-8297. (aalto.fi)
  • Gas chromatography-mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. (wikipedia.org)
  • ISO 12010:2012 specifies a method for the quantitative determination of the sum of short-chain polychlorinated n ‑alkanes, also known as short-chain polychlorinated paraffins (SCCPs), in the carbon bond range n -C 10 to n -C 13 inclusive, in mixtures with chlorine mass fractions ("contents") between 49 % and 67 %, including approximately 6 300 of approximately 8 000 congeners. (iso.org)
  • Development of a thermal desorption-gas chromatography-mass spectrometry method for determination of styrene in air. (edpsciences.org)
  • A thermal desorption-gas chromatography-mass spectrometry method for determination of styrene in industrial indoor and outdoor air is presented. (edpsciences.org)
  • This volume details the principles and instrumentation of gas chromatography-mass spectrometry (CG-MS), and outlines industrial, environmental, pharmaceutical, clinical, toxicological, forensic and food-related applications, revealing findings from the laboratories of 40 contributing scientists around the world using GC-MS in practice. (dattanibookagency.in)
  • Fatty acid composition of the extract was identified by gas chromatography-mass spectrometry with their relative concentrations. (biomedjournal.com)
  • The objective of the present study was to evaluate the effect of biofield energy treatment on the isotopic abundance ratios of PM+1/PM , and PM+2/PM in o- and m-nitrophenol using the gas chromatography-mass spectrometry. (omeka.net)
  • This paper outlines a six-step, data-driven, framework to develop and evaluate gas chromatography mass spectrometry (GC-MS) methods for targeted classes of drugs. (ojp.gov)
  • The Mass Spectrometry technique requires a very pure sample and does not work well for mixtures. (infinitalab.com)
  • It is not possible to make an accurate identification of a particular molecule by gas chromatography or mass spectrometry alone. (wikipedia.org)
  • Separation and identification of phenol-formaldehyde condensates by gas chromatography-mass spectrometry II. (unthsc.edu)
  • The molecules carried in the gas (termed mobile phase), are eluted at different times from the column depending on the affinity of molecules for the stationary phase. (infinitalab.com)
  • If you are interested in finding out more in regards to Gas Chromatography and what Apex's Nitrogen Generators can do in regards to your Gas Chromatography application requirements, check out our range of mini Nevis Nitrogen Generators by following the link below. (apexgasgenerators.com)
  • If the test result is positive, another test called gas-chromatography mass spectrometry (GC-MS) may be done to confirm the results. (medlineplus.gov)
  • Urine was collected before and after each test dose, and analysed for cortisol levels by gas chromatography/mass spectrometry, and for digitalis-like activity both by RIA and by a bioassay measuring 86Rb-uptake into red blood cells. (lu.se)
  • Through the use of Gas Chromatography-Mass Spectrometry (GC-MS) of 27 mummified animal remains (supplied by Buckley & Tunney and Buckley & Fletcher) this thesis identified the presence of imported embalming agents in 75% of the samples tested. (whiterose.ac.uk)