Spectrophotometry, Atomic: Spectrophotometric techniques by which the absorption or emmision spectra of radiation from atoms are produced and analyzed.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Spectrophotometry, Ultraviolet: 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)Spectrophotometry, Infrared: Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Tablets: Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Graphite: An allotropic form of carbon that is used in pencils, as a lubricant, and in matches and explosives. It is obtained by mining and its dust can cause lung irritation.Microchemistry: 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.Oxyhemoglobins: A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.Calibration: 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.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Oxidation-Reduction: 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).Kinetics: The rate dynamics in chemical or physical systems.Copper: A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.Aluminum: A metallic element that has the atomic number 13, atomic symbol Al, and atomic weight 26.98.Indocyanine Green: A tricarbocyanine dye that is used diagnostically in liver function tests and to determine blood volume and cardiac output.Methods: A series of steps taken in order to conduct research.Color: The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.Coloring Agents: Chemicals and substances that impart color including soluble dyes and insoluble pigments. They are used in INKS; PAINTS; and as INDICATORS AND REAGENTS.Lead: A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.19, symbol Pb. (Dorland, 28th)Indicators and Reagents: 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)Trace Elements: A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Bilirubin: A bile pigment that is a degradation product of HEME.Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Colorimetry: Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)MethemoglobinBlood Volume Determination: Method for determining the circulating blood volume by introducing a known quantity of foreign substance into the blood and determining its concentration some minutes later when thorough mixing has occurred. From these two values the blood volume can be calculated by dividing the quantity of injected material by its concentration in the blood at the time of uniform mixing. Generally expressed as cubic centimeters or liters per kilogram of body weight.Hydrogen-Ion Concentration: 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)Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Chromatography, Thin Layer: 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)Magnesium Compounds: Inorganic compounds that contain magnesium as an integral part of the molecule.Flow Injection Analysis: The analysis of a chemical substance by inserting a sample into a carrier stream of reagent using a sample injection valve that propels the sample downstream where mixing occurs in a coiled tube, then passes into a flow-through detector and a recorder or other data handling device.Dithionite: Dithionite. The dithionous acid ion and its salts.Potassium Compounds: Inorganic compounds that contain potassium as an integral part of the molecule.Chromium: A trace element that plays a role in glucose metabolism. It has the atomic symbol Cr, atomic number 24, and atomic weight 52. According to the Fourth Annual Report on Carcinogens (NTP85-002,1985), chromium and some of its compounds have been listed as known carcinogens.Densitometry: The measurement of the density of a material by measuring the amount of light or radiation passing through (or absorbed by) the material.Potassium Iodide: An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)Metals, Heavy: Metals with high specific gravity, typically larger than 5. They have complex spectra, form colored salts and double salts, have a low electrode potential, are mainly amphoteric, yield weak bases and weak acids, and are oxidizing or reducing agents (From Grant & Hackh's Chemical Dictionary, 5th ed)Autoanalysis: Method of analyzing chemicals using automation.Hydrochloric Acid: A strong corrosive acid that is commonly used as a laboratory reagent. It is formed by dissolving hydrogen chloride in water. GASTRIC ACID is the hydrochloric acid component of GASTRIC JUICE.Mercury: A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.Spinal Puncture: Tapping fluid from the subarachnoid space in the lumbar region, usually between the third and fourth lumbar vertebrae.Borates: Inorganic or organic salts and esters of boric acid.Baccharis: A plant genus of the family ASTERACEAE. Other plants called broom include CYTISUS; SPARTIUM; and BROMUS.CarboxyhemoglobinIron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Cerebrospinal Fluid Proteins: Proteins in the cerebrospinal fluid, normally albumin and globulin present in the ratio of 8 to 1. Increases in protein levels are of diagnostic value in neurological diseases. (Brain and Bannister's Clinical Neurology, 7th ed, p221)Reproducibility of Results: 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.Tantalum: Tantalum. A rare metallic element, atomic number 73, atomic weight 180.948, symbol Ta. It is a noncorrosive and malleable metal that has been used for plates or disks to replace cranial defects, for wire sutures, and for making prosthetic devices. (Dorland, 28th ed)Temperature: 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.Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Cadmium: An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Hair: A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.Ferric Compounds: Inorganic or organic compounds containing trivalent iron.Drug Stability: The chemical and physical integrity of a pharmaceutical product.Manganese: A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Flavins: Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.Nephelometry and Turbidimetry: Chemical analysis based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering. In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured. In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.Azo CompoundsChromatography, Gas: 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.Platinum: Platinum. A heavy, soft, whitish metal, resembling tin, atomic number 78, atomic weight 195.09, symbol Pt. (From Dorland, 28th ed) It is used in manufacturing equipment for laboratory and industrial use. It occurs as a black powder (platinum black) and as a spongy substance (spongy platinum) and may have been known in Pliny's time as "alutiae".Electron Transport Complex IV: A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.Palladium: A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.Limit of Detection: Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.Nickel: A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.Particle Size: Relating to the size of solids.Sulfonic Acids: Inorganic or organic oxy acids of sulfur which contain the RSO2(OH) radical.Methylene Blue: A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.Subarachnoid Hemorrhage: Bleeding into the intracranial or spinal SUBARACHNOID SPACE, most resulting from INTRACRANIAL ANEURYSM rupture. It can occur after traumatic injuries (SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurological deficits and reduced mental status.Selenium: An element with the atomic symbol Se, atomic number 34, and atomic weight 78.96. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE.Cobalt: A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.Cytochromes: Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Ultrafiltration: The separation of particles from a suspension by passage through a filter with very fine pores. In ultrafiltration the separation is accomplished by convective transport; in DIALYSIS separation relies instead upon differential diffusion. Ultrafiltration occurs naturally and is a laboratory procedure. Artificial ultrafiltration of the blood is referred to as HEMOFILTRATION or HEMODIAFILTRATION (if combined with HEMODIALYSIS).PicratesCarbon Monoxide: Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. (From Merck Index, 11th ed)Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.Pharmaceutical Preparations: 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.Hydrochlorothiazide: A thiazide diuretic often considered the prototypical member of this class. It reduces the reabsorption of electrolytes from the renal tubules. This results in increased excretion of water and electrolytes, including sodium, potassium, chloride, and magnesium. It is used in the treatment of several disorders including edema, hypertension, diabetes insipidus, and hypoparathyroidism.Environmental Monitoring: 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.Molybdenum: A metallic element with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. (From Dorland, 27th ed)Myoglobin: A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Reference Values: 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.Technology, Pharmaceutical: The application of scientific knowledge or technology to pharmacy and the pharmaceutical industry. It includes methods, techniques, and instrumentation in the manufacture, preparation, compounding, dispensing, packaging, and storing of drugs and other preparations used in diagnostic and determinative procedures, and in the treatment of patients.Quality Control: 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)Ferrous Compounds: Inorganic or organic compounds that contain divalent iron.Melanins: Insoluble polymers of TYROSINE derivatives found in and causing darkness in skin (SKIN PIGMENTATION), hair, and feathers providing protection against SUNBURN induced by SUNLIGHT. CAROTENES contribute yellow and red coloration.Cyanides: Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.Spectroscopy, Fourier Transform Infrared: A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.Spectroscopy, Near-Infrared: A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.Solvents: Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)Electron Transport: The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)Evaluation Studies as Topic: Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.Molecular Structure: 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.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Cattle: 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.Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Blood Volume: Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.Silicon Dioxide: Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Plant Extracts: 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.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Electrons: Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.Micelles: Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.Reference Standards: 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.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Buffers: A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.Antioxidants: Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.Methanol: 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.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Electrochemistry: The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.Magnetic Resonance Spectroscopy: 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).NADP: Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)Drugs, Chinese Herbal: Chinese herbal or plant extracts which are used as drugs to treat diseases or promote general well-being. The concept does not include synthesized compounds manufactured in China.Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.Arsenic: A shiny gray element with atomic symbol As, atomic number 33, and atomic weight 75. It occurs throughout the universe, mostly in the form of metallic arsenides. Most forms are toxic. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), arsenic and certain arsenic compounds have been listed as known carcinogens. (From Merck Index, 11th ed)Malondialdehyde: The dialdehyde of malonic acid.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Carotenoids: The general name for a group of fat-soluble pigments found in green, yellow, and leafy vegetables, and yellow fruits. They are aliphatic hydrocarbons consisting of a polyisoprene backbone.Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.DNA Adducts: The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.Drug Carriers: Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.Metals: Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)Cytochrome c Group: A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Superoxide Dismutase: An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC 188.8.131.52.Catalase: An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Calorimetry, Differential Scanning: Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.Materials Testing: The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Chelating Agents: Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.Carbonic Anhydrases: A family of zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide. They play an important role in the transport of CARBON DIOXIDE from the tissues to the LUNG. EC 184.108.40.206.Sulfhydryl Compounds: Compounds containing the -SH radical.Flavin-Adenine Dinucleotide: A condensation product of riboflavin and adenosine diphosphate. The coenzyme of various aerobic dehydrogenases, e.g., D-amino acid oxidase and L-amino acid oxidase. (Lehninger, Principles of Biochemistry, 1982, p972)Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Nitrogenase: An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 220.127.116.11.Phenobarbital: A barbituric acid derivative that acts as a nonselective central nervous system depressant. It potentiates GAMMA-AMINOBUTYRIC ACID action on GABA-A RECEPTORS, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations.Sensitivity and Specificity: 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)Polyethylene Glycols: Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.Chemistry, Pharmaceutical: Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Food Contamination: The presence in food of harmful, unpalatable, or otherwise objectionable foreign substances, e.g. chemicals, microorganisms or diluents, before, during, or after processing or storage.Oxidative Stress: 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).Ascorbic Acid: A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.Horses: Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.Drug Delivery Systems: Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.Fluorescence: The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.Rats, Sprague-Dawley: 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.Nitrites: Salts of nitrous acid or compounds containing the group NO2-. The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. The organic nitrites may be isomeric, but not identical with the corresponding nitro compounds. (Grant & Hackh's Chemical Dictionary, 5th ed)Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Drug Combinations: Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Edetic Acid: A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.Scattering, Radiation: The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Oxidants: Electron-accepting molecules in chemical reactions in which electrons are transferred from one molecule to another (OXIDATION-REDUCTION).Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Lipid Peroxidation: Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Peroxidase: A hemeprotein from leukocytes. Deficiency of this enzyme leads to a hereditary disorder coupled with disseminated moniliasis. It catalyzes the conversion of a donor and peroxide to an oxidized donor and water. EC 18.104.22.168.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.NAD: A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Escherichia coli: 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.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Anaerobiosis: The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Phosphates: Inorganic salts of phosphoric acid.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.Environmental Exposure: The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.Glutathione Peroxidase: An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC 22.214.171.124.Serum Albumin: A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.Cytochrome P-450 Enzyme System: 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.Permeability: Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Swine: 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).Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Nanoparticles: Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Biological Markers: 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.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Osmolar Concentration: The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Molecular Sequence Data: 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.Protons: Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
A comparison of techniques for the quantitative analysis of hyaluronic acid in equine synovial fluid. (1/8806)A comparison of methods of preparing the hyaluronic acid of equine synovial fluid for quantitative spectrophotographic analysis is presented. A new method is proposed which appears superior to the previous methods. (+info)
The direct spectrophotometric observation of benzo(a)pyrene phenol formation by liver microsomes. (2/8806)Optical spectral repetitive scan analysis during the oxidative metabolism of benzo(a)pyrene by liver microsomal suspensions reveals the time-dependent formation of an intermediate(s) of which the visible spectra resemble those of several benzo(a)pyrene phenols. Liver microsomes from 3-methylcholanthrene-treated rats showed a greater rate of formation of the phenols than did microsomes from control animals; the rate of formation catalyzed by liver microsomes from phenobarbital-pretreated rats was intermediate. When 3-hydroxybenzo(a)pyrene was used as a standard for comparison of activity, the rates of formation of phenols were compared when measured by fluorometric, spectrophotometric, or high-pressure liquid chromatographic analytical techniques. An epoxide hydrase inhibitor, 1,1,1-trichloropropene-2,3-oxide, enhanced phenol formation regardless of the source of liver microsomes, and 7,8-benzoflavone inhibited control and 3-methylcholanthrene-induced microsomal metabolism of benzo(a)pyrene, 7,8-Benzoflavone did not effect benzo(a)pyrene metabolism by liver microsomes from phenobarbital-pretreated rats. The effect of inhibitors on the spectrophotometric assay correlates well with the results obtained from benzo(a)pyrene metabolite analysis using high-pressure liquid chromatography. (+info)
Accumulation of astaxanthin all-E, 9Z and 13Z geometrical isomers and 3 and 3' RS optical isomers in rainbow trout (Oncorhynchus mykiss) is selective. (3/8806)Concentrations of all-E-, 9Z- and 13Z- geometrical and (3R,3'R), (3R, 3'S) and (3S,3'S) optical isomers of astaxanthin were determined in rainbow trout liver, gut tissues, kidney, skin and blood plasma to evaluate their body distribution. Two cold-pelleted diets containing predominantly all-E-astaxanthin (36.9 mg/kg astaxanthin, 97% all-E-, 0.4% 9Z-, 1.5% 13Z-astaxanthin, and 1.1% other isomers, respectively) or a mixture of all-E- and Z-astaxanthins (35.4 mg/kg astaxanthin, 64% all-E-, 18.7% 9Z-, 12.3% 13Z-astaxanthin, and 2.0% other isomers, respectively), were fed to duplicate groups of trout for 69 d. Individual E/Z isomers were identified by VIS- and 1H-NMR-spectrometry, and quantified by high-performance liquid chromatography. Significantly higher total carotenoid concentration was observed in plasma of trout fed diets with all-E-astaxanthin (P < 0.05). The relative E/Z-isomer concentrations of plasma, skin and kidney were not significantly different among groups, whereas all-E-astaxanthin was higher in intestinal tissues and 13Z-astaxanthin was lower in liver of trout fed all-E-astaxanthin (P < 0.05). The relative amount of hepatic 13Z-astaxanthin (39-49% of total astaxanthin) was higher than in all other samples (P < 0.05). Synthetic, optically inactive astaxanthin was used in all experiments, and the determined dietary ratio between the 3R,3'R:3R, 3'S (meso):3S,3'S optical isomers was 25.3:49.6:25.1. The distribution of R/S-astaxanthin isomers in feces, blood, liver and fillet was similar to that in the diets. The ratio between (3S,3'S)- and (3R,3'R)-astaxanthin in the skin and posterior kidney was ca. 2:1 and 3:1, respectively, regardless of dietary E/Z-astaxanthin composition. The results show that geometrical and optical isomers of astaxanthin are distributed selectively in different tissues of rainbow trout. (+info)
Reactivity of cyanate with valine-1 (alpha) of hemoglobin. A probe of conformational change and anion binding. (4/8806)The 3-fold increase in the carbamylation rate of Val-1 (alpha) of hemoglobin upon deoxygenation described earlier is now shown to be a sensitive probe of conformational change. Thus, whereas this residue in methemoglobin A is carbamylated at the same rate as in liganded hemoglobin, upon addition of inositol hexaphosphate its carbamylation rate is enhanced 30% as much as the total change in the rate between the CO and deoxy states. For CO-hemoglobin Kansas in the presence of the organic phosphate, the relative increase in the carbamylation rate of this residue is about 50%. These results indicate that methemoglobin A and hemoglobin Kansas in the presence of inositol hexaphosphate do not assume a conformation identical with deoxyhemoglobin but rather form either a mixture of R and T states or an intermediate conformation in the region around Val-1 (alpha). Studies on the mechanism for the rate enhancement in deoxyhemoglobin suggest that the cyanate anion binds to groups in the vicinity of Val-1 (alpha) prior to proton transfer and carbamylation of this NH2-terminal residue. Thus, specific removal with carboxypeptidase B of Arg-141 (alpha), which is close to Val-1 (alpha) in deoxyhemoglobin, abolishes the enhancement in carbamylation. Chloride, which has the same valency as cyanate, is a better competitive inhibitor of the carbamylation of deoxyhemoglobin (Ki = 50 mM) compared with liganded hemoglobin. Nitrate and iodide are also effective inhibitors of the carbamylation of Val-1 (alpha) of deoxyhemoglobin (Ki = 35 mM); inorganic phosphate, sulfate, and fluoride are poor competitive inhibitors. The change in pKa of Val-1 (alpha) upon deoxygenation may be due to its differential interaction with chloride. (+info)
Negligible amount of copper in hepatic L-tryptophan 2,3-dioxygenase. (5/8806)During the purification of L-tryptophan 2,3-dioxygenase, a protohemoprotein from rat liver, both copper and heme contents of the preparations were found to be progressively increased as purification proceeded. However, the greater part of copper was removed in the late stages of the purification giving a copper to heme ratio less than 0.4. The small amounts of copper could further be reduced by one-half, by a mild treatment of enzyme with chelators such as ethylenedi aminetetraacetate, without any accompanying decrease in enzymatic activity. Since the turnover number of these enzyme preparations expressed per mol of enzyme-bound heme, 200 to 277 min-1 at 25 degrees, were either comparable to or slightly higher than those reported with homogeneous enzyme preparations, the heme in the preparation was considered to be of fully active L-tryptophan 2,3-dioxygenase and, therefore, such a small ratio of copper to heme, 0.1 to 0.3, indicated that copper is not a constituent of L-tryptophan 2,3-dioxygenase of rat liver. The findings were thus inconsistent with the results of Brady et al. (Brady, F. O., Monaco, M. E. Forman, H. J. Schutz, G., and Feigelson, P. (1972) J. Biol. Chem. 247, 7915-7922), who found that L-tryptophan 2,3-dioxygenase contained 2 g atoms of copper and 2 mol of heme/mol of enzyme. Possible reasons for this discrepancy have been discussed. (+info)
Selenium redox biochemistry of zinc-sulfur coordination sites in proteins and enzymes. (6/8806)Selenium has been increasingly recognized as an essential element in biology and medicine. Its biochemistry resembles that of sulfur, yet differs from it by virtue of both redox potentials and stabilities of its oxidation states. Selenium can substitute for the more ubiquitous sulfur of cysteine and as such plays an important role in more than a dozen selenoproteins. We have chosen to examine zinc-sulfur centers as possible targets of selenium redox biochemistry. Selenium compounds release zinc from zinc/thiolate-coordination environments, thereby affecting the cellular thiol redox state and the distribution of zinc and likely of other metal ions. Aromatic selenium compounds are excellent spectroscopic probes of the otherwise relatively unstable functional selenium groups. Zinc-coordinated thiolates, e.g., metallothionein (MT), and uncoordinated thiolates, e.g., glutathione, react with benzeneseleninic acid (oxidation state +2), benzeneselenenyl chloride (oxidation state 0) and selenocystamine (oxidation state -1). Benzeneseleninic acid and benzeneselenenyl chloride react very rapidly with MT and titrate substoichiometrically and with a 1:1 stoichiometry, respectively. Selenium compounds also catalyze the release of zinc from MT in peroxidation and thiol/disulfide-interchange reactions. The selenoenzyme glutathione peroxidase catalytically oxidizes MT and releases zinc in the presence of t-butyl hydroperoxide, suggesting that this type of redox chemistry may be employed in biology for the control of metal metabolism. Moreover, selenium compounds are likely targets for zinc/thiolate coordination centers in vivo, because the reactions are only partially suppressed by excess glutathione. This specificity and the potential to undergo catalytic reactions at low concentrations suggests that zinc release is a significant aspect of the therapeutic antioxidant actions of selenium compounds in antiinflammatory and anticarcinogenic agents. (+info)
Structure and function in rhodopsin: further elucidation of the role of the intradiscal cysteines, Cys-110, -185, and -187, in rhodopsin folding and function. (7/8806)The disulfide bond between Cys-110 and Cys-187 in the intradiscal domain is required for correct folding in vivo and function of mammalian rhodopsin. Misfolding in rhodopsin, characterized by the loss of ability to bind 11-cis-retinal, has been shown to be caused by an intradiscal disulfide bond different from the above native disulfide bond. Further, naturally occurring single mutations of the intradiscal cysteines (C110F, C110Y, and C187Y) are associated with retinitis pigmentosa (RP). To elucidate further the role of every one of the three intradiscal cysteines, mutants containing single-cysteine replacements by alanine residues and the above three RP mutants have been studied. We find that C110A, C110F, and C110Y all form a disulfide bond between C185 and C187 and cause loss of retinal binding. C185A allows the formation of a C110-C187 disulfide bond, with wild-type-like rhodopsin phenotype. C187A forms a disulfide bond between C110 and C185 and binds retinal, and the pigment formed has markedly altered bleaching behavior. However, the opsin from the RP mutant C187Y forms no rhodopsin chromophore. (+info)
Specificity of native-like interhelical hydrophobic contacts in the apomyoglobin intermediate. (8/8806)On exposure to mildly acidic conditions, apomyoglobin forms a partially folded intermediate, I. The A, B, G, and H helices are significantly structured in this equilibrium intermediate, whereas the remainder of the protein is largely unfolded. We report here the effects of mutations at helix pairing sites on the stability of I in three classes of mutants that: (i) truncate hydrophobic side chains in native helix packing sites, (ii) truncate hydrophobic side chains not involved in interhelical contacts, and (iii) extend hydrophobic side chains at residues not involved in interhelical contacts. Class I mutants significantly decrease the stability and cooperativity of folding of the intermediate. Class II and III mutants show smaller effects on stability and have little effect on cooperativity. Qualitatively similar results to those found in I were obtained for all three classes of mutants in native myoglobin (N), demonstrating that hydrophobic burial is fairly specific to native helix packing sites in I as well as in N. These results suggest that hydrophobic burial along native-like interhelical contacts is important for the formation of the cooperatively folded intermediate. (+info)
Molar absorptivity / molar extinction coefficients for inorganic solutions | VIPEr
Greetings VIPErs,. I am looking for molar absorptivity (or molar extinction coefficient) data for a handful of inorganic compounds (in solution), as a function of wavelength in the UV/visible spectrum. Can you help?. The compounds are Co(NO3)2, CoCl2, K2CrO7, AuCl3, K2CrO4, NiCl2, CuSO4, and KMnO4.. I have tried the following online resources without success: the CRC Handbook, the NIST Chemical WebBook, the Combined Chemical Dictionary, PubChem, SciFinder, and Google.. I would greatly appreciate your suggestions for resources that may have these data! If the search is to no avail, I will probably resort to tracking down a UV/vis spectrophotometer (and the various chemicals) and taking the measurements myself, but I would hugely appreciate a more reliable source, in addition to not having to do this.. Many thanks! ...
Leicester Research Archive: A concurrent multi-axis differential optical absorption spectroscopy system for the measurement of...
The development of a new concurrent multi-axis sky viewing spectrometer for monitoring rapidly changing urban concentrations of nitrogen dioxide is detailed. The concurrent multi-axis differential optical absorption spectroscopy (CMAX-DOAS) technique involves simultaneous spectral imaging of the zenith and off-axis measurements of spatially resolved scattered sun-light. Trace gas amounts are retrieved from the measured spectra using the established DOAS technique. The potential of the CMAX DOAS technique to derive information on rapidly changing concentrations and the spatial distribution of nitrogen dioxide in an urban environment is demonstrated. Three example datasets are presented from measurements during 2004 of tropospheric NO2 over Leicester, UK (52.62 °N, 1.12 °W). The data demonstrates the current capabilities and future potential of the CMAX-DOAS method in terms of the ability to measure the real-time spatially disaggregated urban NO2 ...
Differential optical absorption spectroscopy (DOAS) measurements of atmospheric ammonia in the mid-ultraviolet from a dairy :...
Molar extinction coefficient calculation. | Physics Forums
Biology-Online • View topic - Molar Extinction Coefficient
The extinction coefficient is present in the beer-lambert law (A=ECL). However, how would I calculate the extinction coefficient from a graph where concentration is on the x-axis and optical density on the y-axis? Would I have to work out a gradient? And so, where do I go next to work out the extinction coefficient ...
Team:TU Delft/Project/solubility/characterization - 2010.igem.org
Besides proving the production of the protein, we wanted to measure the increase of emulsification as well. The only problem was that emulsification is not easily determined. In literature we found many methods that involve spectrophotometric measurements of turbidity after mixing. Although many articles show nice graphs, we were unable to reproduce them. So, in our opinion measuring turbidity is rather arbitrary and there is a clear need for a new emulsification assay. Example from literature Figure 1 on the right shows a calibration graph with a linear increase in absorbance at 660 nm for increasing concentrations of SDS (●). Under the standard detergent assay conditions, various components like 200 mM NaCl (□), 2.0 mM CaCl2 (♦), 10% glycerol (■), 100 μg microsomal membranes (open diamond), 0.2 mM Triton X-100 (▲) and 2.5 mM CHAPS (○) were added and the turbidity was measured. Error bars represent the deviation from five independent experiments and each one performed in duplicate. ...
Biology-Online • View topic - molar extinction coefficient
As you decrease the concentration the absorbance decreases and they should both become zero together so the intercept should be zero; that means from Y=mx+c for c=0 you only need Y=mx. For A=ecl, l=1cm and so except for its contribution to the units you can ignore it. That leaves you with A=ec, which is in the form Y=mx. As you vary the concentration the absorbance changes. The slope of their linear relationship (in the Beers law range, A,~2) is the extinction coefficient. To lay it out explicitly ...
User:Sanuja Mohanaraj/Notebook/Experimental Biochemistry 1 Fall 2017/2017/10/17 - OpenWetWare
Figures (a) through (f) display the absorbance spectra of the gold nanoparticle mixed with each of the prepared reducing agents solutions. Figure (a) displays the absorbance spectrum of the AuNP-Cellulose nanocrystal solution, with no apparent peaks. Figure (b) displays the absorbance spectrum of the AuNP-Chitosan solution, with no observed peaks. Figure (c) displays the absorbance spectrum of the AuNP-Fructose solution, with an observed peak at wavelength 250nm. Figure (d) displays the absorbance spectrum of the AuNP-Galactose solution, with an observed peak at wavelength 250nm. Figure (e) displays the absorbance spectrum of the AuNP-H2AsCt solution, with a slight observed peak at wavelength 600nm. Figure (f) displays the absorbance spectrum of the AuNP-Na3Ct solution, with an observed steep peak at wavelength 550nm. ...
Selenium Laboratory Spectrophotometer Sodium / Ultraviolet Visible Spectroscopy Double Beam - Macylab
Open Library - Chemical Analysis and Material Characterization by Spectrophotometry
Chemical Analysis and Material Characterization by Spectrophotometry integrates and presents the latest known information and examples from the most up-to-date literature on the use of this method for chemical analysis or materials characterization. Accessible to various levels of expertise, everyone from students, to practicing analytical and industrial chemists, the book covers both the fundamentals of spectrophotometry and instrumental procedures for quantitative analysis with spectrophotometric techniques. It contains a wealth of examples and focuses on the latest research, such as the investigation of optical properties of nanomaterials and thin solid films.
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A continuous spectrophotometric assay for monitoring adenosine 5'-monophosphate production. | Docphin
Chapter 14: Nucleic Acids
Place both cuvettes into a dual beam temperature regulated UV spectrophotometer and measure the absorbance of the sample at 260 nm at temperatures ranging from 25° C to 80° C. Continue to increase the temperature slowly and continue reading the absorbance until a sharp rise in absorbance is noted. Alternatively: a. Place the cuvettes into a waterbath at 25 ° C and allow to temperature equilibrate. Remove the blank, wipe the outside dry and rapidly blank the instrument at 260 nm. Transfer the sample to the spectrophotometer (be sure to dry and work rapidly) and read the absorbance. b. Raise the temperature of the bath to 50° C and repeat step a. c. Raise the temperature sequentially to 60° C, 65° C, 70° C, 75° C and 80° C and repeat the absorbance measurements. d. Slowly raise the temperature above 80° and make absorbance measurements every 2° until the absorbance begins to increase. At that point, increase the temperature, but continue to take readings at 1° C intervals. ...
Batch technique was carried out for discovering adsorption of Br - Free Speech For Students
Batch technique was carried out for discovering adsorption of Br.G, To.B and Tr.B dyes onto [email protected] Different volume of dyes were taken from stock solution and diluted to 25 ml water at the same pH. 25 ml of these dyes were added to specific amount of [email protected] and shacked for 1 h at room temperature. The absorbance of dye solution remained were measured spectrophotometrically at maximum wavelength for Br.G, To.B and Tr.B dyes. By knowing C? (initial concentration, mg/L) and Ce (concentration of dye remains, mg/L), V is the volume of Br.G, To.B and Tr.B dyes and m is amount of [email protected] added (g). The percentage removal (%E) of dyes and capacity of [email protected] was calculated by equations ...
190-850nm Ultromicro Spectrophotometer / Cuvette Spectrophotometer - Macylab
Human αHSP(Alpha-Hemoglobin Stabilizing Protein) ELISA Kit-TK03005| TZYBIOTECH Life Sciences
This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antigen specific to Human αHSP(Alpha-Hemoglobin Stabilizing Protein). Standards or samples are added to the micro ELISA plate wells and combined with the specific antigen. Then a biotinylated detection antigen specific for Human αHSP(Alpha-Hemoglobin Stabilizing Protein) and Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Human αHSP(Alpha-Hemoglobin Stabilizing Protein), biotinylated detection antigen and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The OD value is proportional to the concentration of Human ...
AMT - Evaluation of MAX-DOAS aerosol retrievals by coincident observations using CRDS, lidar, and sky radiometer inTsukuba,...
Abstract. Coincident aerosol observations of multi-axis differential optical absorption spectroscopy (MAX-DOAS), cavity ring-down spectroscopy (CRDS), lidar, and sky radiometer were conducted in Tsukuba, Japan, on 5-18 October 2010. MAX-DOAS aerosol retrieval (for aerosol extinction coefficient and aerosol optical depth at 476 nm) was evaluated from the viewpoint of the need for a correction factor for oxygen collision complexes (O4 or O2-O2) absorption. The present study strongly supports this need, as systematic residuals at relatively high elevation angles (20 and 30°) were evident in MAX-DOAS profile retrievals conducted without the correction. However, adopting a single number for the correction factor (fO4 = 1.25) for all of the elevation angles led to systematic overestimation of near-surface aerosol extinction coefficients, as reported in the literature. To achieve agreement with all three observations, we limited the set of elevation angles to ≤10° and adopted an ...
Precise spectrophotometry of small quantities of drugs in the presence of irreproducible quantities of impurities | Meta
A variety of methods of spectrophotometric assay of compounds in the presence of one or more irrelevant impurities have been recently described, employing, for example, the use of Legendre polynomials and trigonometric functions. The use of least-squares solutions of overdetermined systems (Scheid 1968) in spectrophotometry is outlined, with conditions under which simplified overdetermined systems have been used for precise spectrophotometric assay of small quantities of drug substances in the presence of largely irreproducible quantities of irrelevant impurities. ...
Which shows an absorption band at a larger wavenumber: a carbonyl group bonded to an sp3 | StudySoup
Analytica EBC | Malt | 4.9.2 - Soluble Nitrogen of Malt: Spectrophotometric Method
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How To Repair Spectrophotometry Lab Sources Of Error (Solved)
With now having the known absorbance of each substance, it is possible to substitute the absorbance value for the y variable and solve for x, which represents the iron concentration. Its absorbance was read and recorded again. When I plotted the absorbances found against the concentrations, I was left with nearly a straight line that goes almost directly through the origin. Why Is It Necessary To Measure The Absorbance At λmax This is the end of the preview. Please upload a file larger than 100x100 pixels We are experiencing some problems, please try again. I could then find the value of x, which was the concentration. Also, if the solution with the unknown in it was boiled, that may cause it to form something different than we wanted to measure and that would cause error, too. click site If one knows the molar absorptivity and path length, anabsorbance measurement directly gives concentration. Generated Fri, 28 Oct 2016 22:40:14 GMT by s_wx1199 (squid/3.5.20) Beers Law says that absorbance is ...
Nutritech - Super Protein Complex
The addition of Aminogen© (cutting edge digestive enzymes) provides maximum absorption. Aminogen© gives you more from your protein, by helping your body breakdown and absorb more Amino acids and maintain a better nitrogen balance. Clinical trials prove that Aminogen© boast levels of all amino acids, including arginine and glutamine and releases much more branched chained amino acids, leucine, isoleucine and valine.. ...
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Comprehensive immune-boosting, antioxidant formula for great energy, unmatched immune protection and defense. It contains over 500 different, immune-boosting bioflavonoids and is a natural thymus stimulant. Propolis Complex supports the bodys immune-active processes, especially skin, including stubborn cases. It is 100% natural, pesticide-free European Propolis complexed with nutraceutical-grade synergists and co-factors, such as Coral Mineral, Indian Noni, European Multi-Pollen extract and stabilized whole rice bran for maximum absorption and utilization ...
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Practical Advanced TMD Practice- Level 2 - LVI Global
The Practical Advanced TMD Practice Continuum is designed to take the serious Physiologic dentist to a level, where he or she can master the patient diagnosis and treatment planning. Topics include: Scan Interpretation, TMD, Anatomy, Physiology, Radiology, Pharmacology, Sleep Breathing Disorders, Risk Management, plus much, much more. It is designed to be a systematic and synergistic educational delivery of the practical, patient oriented material for maximum absorption that will allow the attendee to become experts in the field of Physiologic Dentistry. This set of courses will allow the participant to trouble shoot the myriad of difficult cases that need differential diagnoses involving the above disciplines.. Pat II will build on the information in Level 1 and further explore aspects that provide the practitioner to come up with a differential diagnosis when treating complicated cases. All disciplines mentioned in the Post Core Continuum summary synopsis Case Therapies will be discussed and ...
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Spectrophotometric assay for B-lactamases
Hi ! Im a student of Ngee Ann Polytechnic. My classmates and I are doing a project on characterisation of Beta- lactamases. We need a standard protocol for the spectrometric assay of b-lactamases DESPERATELY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Any kind person who have the protocol, PLEASE reply this note. Please include the substrate to use, buffer,pH of buffer, amount of substrate and enzyme to add, the wavelength to scan (lamda maximun) etc. We shall be eternally grateful to you. THANK YOU ...
What is spectroscopy? - Ultraviolet and Visible Spectroscopy | Coursera
Double Beam Uv Visible Spectrophotometer Manufacturers and Suppliers - Price - MesuLab
Protein Quantitation using the Bradford assay and Spectrophotometry Free Short Essay Example
More Protein Essay Topics.. The spectrophotometer is an absorbance measuring instrument that produces light through two bulbs; the first a visible light and the second one which produces an ultra violet light. Five known substances from 0. 2 mg/ml to 1. 0 mg/ml, one blank sample and two unknown were used to be tested. In the beginning these solutions were already in 1. 5ml microfuge tubes, the amount of stock needed for each was then calculated with the equation C1V1 = C2V2.. C1 being the concentration, V1 the value of the starting solutions, C2 the desired concentration of the final stock and V2 the volume of the final stock. Using pipettes, the proportionate amounts mixed with distilled water were used and placed in separate falcon tubes. The concentrations were then mixed with a 5. 0 ml of diluted dye reagent, followed by a five minute incubation period. The solutions were each pipetted into cuvettes and placed in the spectrophotometer which was set at 595mm.. The blank sample was the first ...
Principle of Spectrophotometry - DnaTube.com - Scientific Video and Animation Site
Notice: Except where noted, spectra from this collection were measured on dispersive instruments, often in carefully selected solvents, and hence may differ in detail from measurements on FTIR instruments or in other chemical environments. More information on the manner in which spectra in this collection were collected can be found here. Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived. ...
Spectrophotometric measurement of carboxyhemoglobin and methem...
Error in noninvasive spectrophotometric measurement of blood hemoglobin concentration under conditions of blood loss -...
Blogs | IO Rodeo Inc.
The molar extinction coefficient (ε) is a measure of how strongly a molecule absorbs light at a specific wavelength. Molar extinction coefficient values are unique to each molecule and wavelength and have units M-1 cm-1. As ε is a fixed constant at a specific wavelength, it can be used to determine the concentration of a solution from its absorbance values (using a fixed path length of 1cm ) using the Beer-Lambert equation:. Concentration (M) = Abs / ε Molar extinction coefficients are reported at specific wavelengths (λ max) with a range of 2-3nm. For example, Erythrosin B (red food dye # 3) has a reported extinction coefficient of 82500 at 524-528 nm - i.e. with a 4 nm range. The LEDs in the colorimeter have a much broader bandwidth of 18, 33 and 25 nm for the red, green and blue LEDs respectively. Therefore it is necessary to determine the molar extinction coefficient with this instrument to get accurate concentrations. Below we desribe how we have determined the molar extinction ...
Gold and alloy nanoparticles in solution and thin film assembly: Spectrophotometric determination of molar absorptivity<...
TY - JOUR. T1 - Gold and alloy nanoparticles in solution and thin film assembly. T2 - Spectrophotometric determination of molar absorptivity. AU - Maye, Mathew M.. AU - Han, Li. AU - Kariuki, Nancy N.. AU - Ly, Nam K.. AU - Chan, Wai Ben. AU - Luo, Jin. AU - Zhong, Chuan Jian. PY - 2003/10/31. Y1 - 2003/10/31. N2 - The spectrophotometric determination of molar absorptivities of the surface plasmon (SP) resonance for gold and gold-silver nanoparticles is reported. The importance of the optical parameter for assessing concentrations of nanoparticles in solution reactions and for estimating thickness of thin film assembly of nanoparticles is highlighted. The high monodispersity (5.6±0.4nm) of decanethiolate-capped gold nanoparticles produced by thermally activated processing protocol served as a model system, which yielded an ε value of 1.1×107M-1cm-1. This value was also compared with values determined similarly for nanoparticles of different core sizes and compositions, including ...
Aragon and Yenista partner for optical spectrum analysis | Fibre Systems
Test and measurement equipment manufacturers Aragon Photonics and Yenista Optics have signed an agreement to collaborate on high-resolution optical spectrum analysis equipment. Founded in 2004 in Zaragoza, Spain, Aragon Photonics is the manufacturer of the BOSA, an advanced high-resolution optical spectrum analyser (OSA) based on stimulated Brillouin scattering.
HMA-TMN Total Manganese Heavy Metal Analyzer Fuzhou Fuguang Water Science&Technology Co.,Ltd
HMA-TMN Total Manganese Heavy Metal Analyzer-Fuzhou Fuguang Water Science&Technology Co.,Ltd --Measurement principle: The instrument is detected by colorimetric spectrophotometry. The sample is first added with digestion reagents, and then pumped to the high-temperature digestion unit for high-temperature digestion. The total manganese in the sample is digested into divalent manganese ions. The divalent manganese ion of the sample reacts with formaldehyde oxime in a slightly alkaline solution and forms a brown colored complex. The spectrophotometric measurement is performed at a wavelength of 470 nm. According to the initial color of the sample and the color change after adding the developer Different degrees to determine the concentration of the analyzed sample. Typical applications: surface water, industrial wastewater (such as electrolytic manganese wastewater), and online monitoring of total manganese at the inlet and outlet of sewage plants
Wavelength interdependence assessment of all-optical switching in zinc borate glasses | (2012) | Abdel-Baki | Publications |...
Lithium tungsten borate photonic glass is prepared by the conventional melt-quench technique. Due to semiconductor-like behavior of zinc oxide, the glass is doped by ZnO to adapt its optical nonlinearity. Fresnel-based spectrophotometric measurements and Lorentz dispersion theory are applied to study (in a very wide range of photon energy from 0.5 to 6.2 eV) the dispersion of second-order refractive index, two-photon absorption coefficient, and third-order optical susceptibility of the glass. The figure of merit (FOM) needed for optical switching applications is estimated. We reveal the importance of determining the dispersion of the optical nonlinear parameters to find out the appropriate operating wavelength for optimum FOM of the glass ...
Determination of total phenolic content of Prunella L. by immobilized enzyme bioreactor - Analytical Methods (RSC Publishing)
A new method for determination of total phenolic content of four Prunella L. species was developed by immobilizing horseradish peroxidase (HRP) on styrene-divinylbenzene-polygluteraldehyde (STY-DVB-PGA) polymer. The method is based on the spectrophotometric measurement of the final quinone-imine colored prod
Microspectrophotometer | Define Microspectrophotometer at Dictionary.com
An effective spectrophotometric determination of palladium with 4-(2-pyridylazo)-resorcinol (PAR) using molten naphthalene as a diluent has been studied. A red complex of palladium with PAR is formed at 90 oC. In the range of pH 9.0-11.0, the complex is quantitatively extracted into molten naphthalene. The organic phase is anhydrously dissolved in CHCl3 to be determined spectrophotometrically at 520 nm against the reagent blank. Beers law is obeyed over the concentration range of 0.1-2 μg·mL-1. The molar absorptivity and Sandells sensitivity are 8.0 × 105 L·mol-1·cm-1 and 0.49 μg·cm-2 respectively. From the results of tolerance limits, it was found that there was no interferences were observed for most of the ions examined and those somewhat high interferences by Co(II), Fe(II) and Bi(III) could be effectively masked by EDTA ...
Exploring How Spectrophotometric Analysis Can Enhance Color Consistency in Ceramic Tile - HunterLab Horizons Blog
A Spectrophotometric Analysis of Pigments in Apples, Russian Journal of Plant Physiology | 10.1023/A:1016780624280 | DeepDyve
Spectrophotometric analysis of myocardial oxygen metabolism in perfused rat hearts
Utilize Spectrophotometric Analysis to Catch a Thief in the Art World
DYE FOR OPTICAL INFORMATION RECORDING MEDIUM AND OPTICAL INFORMATION RECORDING MEDIUM - Patent application
0035] Any of these dyes can be dissolved in a TFP (tetrafluoropropanol) solution, for example, and the obtained dye solution can be applied by the spin coat method in such a way as to achieve the optical density (hereinafter abbreviated as "OD") corresponding to the minimum DC jitter. Here, OD indicates the absorbance of the dye at the maximum optical absorption wavelength. The OD of each dye is measured by applying the recording layer 5 directly on the substrate 2 shown in FIG. 1 and measuring the absorbance using a beam having the maximum absorption wavelength of the applicable dye. For example, a dye expressed by (Chemical Formula 3) has the absorption spectrum shown in FIG. 2. Since its maximum absorption wavelength (λmax) is 383 nm, the absorbance is measured with a beam of 383 nm in wavelength to derive the OD. The OD is adjusted according to the film forming conditions (rotational speed, time, etc.). The OD corresponding to the minimum DC jitter is determined by preparing multiple sample ...
spectrophotometer cuvettes - china spectrophotometer cuvettes manufacturers and suppliers
On one hand, centrifugal separation could remove the graphite par | Tyrosine Kinase inhibitor|Tyrosine Kinase|Receptor Tyrosine...
On one hand, centrifugal separation could remove the graphite particles which do not dissolve in water. On the other hand, it has accelerated the settlement process of graphite emulsion so as to click here evaluate the dispersion stability. After centrifugation, the supernatants are separated to analyze the absorbance on a UV-vis spectrophotometer. Figure 3 shows the changing curves between absorbance and wavelength at different temperatures. The curves in Figure 3 exhibit a similar change tendency.. There is nearly no absorption when the wavelength is beyond 550 nm. The absorbance increases with the decrease of wavelength in the range of 550 to approximately 250 nm, and the increasing rate MK0683 becomes larger and larger. There exhibits a one-to-one correspondence between absorbance and wavelength within the range 550 to approximately 250 nm.. Any wavelength in this range could be used as the characteristic absorption wavelength to evaluate the dispersion stability of graphite emulsion. In ...
Changes in raspberry pigments during processing and storage
The retention of pigments in processed raspberries is a function of the process method and conditions of subsequent storage. The presence of sucrose and the nature of the headspace gas also influences the retention of the pigment. The effect of some of the above variables on the pigments was investigated. Variables imposed were: (1) concentration of syrup, (2) headspace gas atmosphere, (3) temperature, and (4) time of storage. Separation of the pigment of Willamette red raspberries and black raspberries was made by column chromatography and the pigments were analyzed. spectrophotometrically. The results showed the following: 1. The pigments of Willamette red raspberries consisted of four separate cyanins as based on the R [subscript f] values and characteristic wavelengths of maximum absorption. The pigments of black raspberries consisted of three fractions. 2. On the basis of R [subscript f] values and wavelengths of maximum absorption only two of the constituent fractions were the same. 3. The ...
NADPH as a co-substrate for studies of the chlorinating activity of myeloperoxidase | Biochemical Journal
The reinvestigation of the kinetics of myeloperoxidase (MPO) activity with the use of NADPH as a probe has allowed us to determine the effects of H2O2, Cl- ion and pH on the MPO-dependent production of HOCl. The chlorination rate of NADPH did not depend on NADPH concentration and was entirely related to the rate of production of HOCl by MPO. The overall oxidation of NADPH occurred similarly in the absence of O2 and was insensitive to scavengers of the superoxide radical anion. Experiments performed on the direct oxidation of NADPH by MPO in the presence and the absence of H2O2 showed that neither the rate nor the stoichiometry of the reaction could interfere in the NADPH oxidation process involved in the steady-state chlorination cycle. The oxidation of NADPH was characterized by a decrease in the A339 of the reduced nicotinamide with the concomitant appearance of a new chomophore with absorbance maximum at 274 nm, characterized by isosbestic points at 300 and 238 nm. The reaction product did ...
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Measurement of sulfobromophthalein uptake in isolated rat hepatocytes by a direct spectrophotometric method. | Archivio della...
A spectrophotometric technique is described for the continuous recording of sulfobromophthalein uptake by isolated hepatocytes. The technique is based on the principle that sulfobromophthalein behaves as a pH-indicator and may be followed photometrically when moving from the medium at pH 7.8 into the interior of the cell. Data show that upon addition of cells to a sulfobromophthalein solution, an absorbance change can be recorded. The kinetics of the process is biphasic and the initial rate is linearly related to the amount of cells added. By this technique it was confirmed that the substrate dependence of the initial velocity of transport is a compound function including a saturable portion with an apparent Km in the mu molar region. Experiments carried out either in the presence of valinomycin or of high concentrations of potassium chloride indicate that the presence of a membrane potential opposes the entry of sulfobromophthalein into isolated hepatocytes. This finding is in agreement with ...
Optical absorption studies of sodium doped poly(cyanoterephthalylidene)
The effects of doping poly(cyanoterephthalylidene) with sodium in ultrahighvacuum been studied by optical absorption spectroscopy. Upon doping, new optical transitions are observed within the bandgap; the characteristics of these transitions are consistent with the formation of bipolarons. The optical absorption results are confirmed by direct measurements of the doping-induced gap states using ultraviolet photoelectron spectroscopy.. ...
Uv Vis Spectrophotometer Price, Uv Vis Spectrophotometer Price Suppliers and Manufacturers at Alibaba.com
CRAIC Technologies Microspectrophotometer & Microspectrometer
CRAIC designs advanced ultraviolet-visible-near-infrared microspectrophotometer, UV microscope, NIR microscope, SWIR microscope, Raman microspectrometer, Raman microscope, microscope spectrophotometer and microscope spectrometer solutions for non-destructive analysis of microscopic samples by transmission and fluorescence and reflectance and polarization microspectroscopy.
protein tumor markers - Journal for the International Association for Laboratory Learning and Technology
Description: This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to Human CA242. Standards or samples are added to the micro ELISA plate wells and combined with the specific antibody. Then a biotinylated detection antibody specific for Human CA242 and Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Human CA242, biotinylated detection antibody and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 nm Â± 2 nm. The OD value is proportional to the concentration of Human CA242. You can calculate the concentration of Human CA242 in the samples by comparing the OD of ...
anti Mechanistic Target of Rapamycin serine - Journal for the International Association for Laboratory Learning and Technology
Description: This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to Human mTOR. Standards or samples are added to the micro ELISA plate wells and combined with the specific antibody. Then a biotinylated detection antibody specific for Human mTOR and Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Human mTOR, biotinylated detection antibody and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 nm Â± 2 nm. The OD value is proportional to the concentration of Human mTOR. You can calculate the concentration of Human mTOR in the samples by comparing the OD of the ...
Each well of the strip is coated with a specific capture antibody to detect its corresponding cytokine in the sample. Therefore, 8 different proteins can be measures simultaneously. The test sample reacts simultaneously with two antibodies, resulting in the cytokines being sandwiched between the solid phase and enzyme-linked antibodies. After incubation, the wells are washed to remove unbound-labeled antibodies. The HRP substrate, TMB, is then added and causes a blue color change. The reaction is then terminated with Stop Solution, resulting in a yellow color. The concentrations of oxidative stress cytokines are directly proportional to the color intensity of the test sample. Absorbance is measured spectrophotometrically at 450 nm. The expression levels of these cytokines can be quantitatively compared between samples.. ...
Spectrophotometer India, Spectrophotometer Manufacturer, Spectrophotometer Suppliers and Spectrophotometer Exporters in India
CN105806508B - A kind of self calibration fiber temperature sensing system - Google Patents
The embodiment of the invention discloses a kind of self calibration fiber temperature sensing systems, including master controller 10, light source set drive 20, light source group 30, optical multiplexer 40, optical spectrum analyser 50 and temperature sensor group 60, the master controller 10 respectively with the light source set drive 20, the optical multiplexer 40 is connected with the optical spectrum analyser 50, the light source set drive 20 is connected with the light source group 30, the light source group 30 is connected with the optical multiplexer 40, the optical multiplexer 40 is connected with the temperature sensor group 60, the master controller 10 is used for the light source group 30 into the calibration of line light source waveform, and the calibration of line drift is carried out to the optical spectrum analyser 50.Using the present invention, may be implemented to calibrate for error, the reliability of temperature detection when improving long.
The absorbance of a protein solution measured in a 1.0 cm cuvette at 278
... nm was 1.145. The protein content of that solution, calculated from quantitative amino acid analysis, was 256 micrograms/mL. Calculate the extinction coefficient of the protein in unitsbof mL/mg/cm. Assume that the molecular mass of the protein was 13,000. Calculate the molar extinction coefficient. ...
O<sub>2</sub> release from Hb vesicles evaluated using an artificial, narrow O<sub>2</sub>-permeable tube: Comparison with RBCs...
TY - JOUR. T1 - O2 release from Hb vesicles evaluated using an artificial, narrow O2-permeable tube. T2 - Comparison with RBCs and acellular Hbs. AU - Sakai, Hiromi. AU - Suzuki, Yoji. AU - Kinoshita, Megumi. AU - Takeoka, Shinji. AU - Maeda, Nobuji. AU - Tsuchida, Eishun. PY - 2003/12. Y1 - 2003/12. N2 - A phospholipid vesicle that encapsulates a concentrated hemoglobin (Hb) solution and pyridoxal 5′-phosphate as an allosteric effector [Hb vesicle (HbV) diameter, 250 nm] has been developed to provide an O2 carrying ability to plasma expanders. The O2 release from flowing HbVs was examined using an O2-permeable, fluorinated ethylenepropylene copolymer tube (inner diameter, 28 μm) exposed to a deoxygenated environment. Measurement of O2 release was performed using an apparatus that consisted of an inverted microscope and a scanning-grating spectrophotometer with a photon-count detector, and the rate of O2 release was determined based on the visible absorption spectrum in the Q band of Hb. HbVs ...
Development and Validation of Vierordt's and Absorbance Ratio Spectrophotometric Methods for Simultaneous Estimation of Aspirin...
The present study deals with the development and validation of two simple, accurate and precise spectrophotometricmethods for estimation of Aspirin (AS) and Omeprazole (OMP) in their binary mixture. The first method was developed using Vierordts simultaneous equation method. It involves absorbance measurement at 257 and 300 nm (λmax of AS and OMP) in methanol. Second method involves the formation of Q-absorbance equation using the respective absorptivity values at 284.5 nm (isoabsorptive point) and 300 nm (λmax of OMP). The drugs obey Beers Lamberts law in the concentration range of 4-20 µg/mL and 2-10 µg/mL for AS and OMP respectively for both the methods. Limit of quantitation for Vierordts method for both the drugs was found to be 0.85 µg/mL, whereas for absorbance ratio method it was 0.68 and 0.88 µg/mL for AS and OMP respectively. % recovery for both the drugs was in the range of 99.78-100.31% indicating excellent accuracy for both the methods. The methods were precise, with a relative
MEDLINE - Resultado p gina 1
The charge transfer (CT) interaction of 2-aminopyrimidine (AP) with chloranilic acid (CLA) as π-acceptor was investigated spectrophotometrically in acetonitrile at different temperatures in the range of 25-50 C. The 1:1 stoichiometry of the synthesized CT complex was detected using straight line method. Benesi-Hildebrand equation was used to determine the association constant (K ), molar extinction coefficient (ε) and other physical parameters. Various thermodynamics parameters such as enthalpy (ΔH), entropy (ΔS) and free energy (ΔG) were determined using UV-Visible spectrophotometry in acetonitrile at different temperatures. H NMR, FTIR, ESI-MS, elemental analyses, and UV-Visible techniques were used to characterize the hydrogen-bonded CT complex. H NMR spectroscopy was also used for the analysis of the CT complex where both hydrogen bond and charge transfer were present in its molecular composition. The interaction of the selected organic compound with Ct-DNA was well investigated using ...
Determination of the branch-point energy of InN : chemical trends in common-cation and common-anion semiconductors - WRAP:...
Bulk and surface electronic properties of Si-doped InN are investigated using high-resolution x-ray photoemission spectroscopy, optical absorption spectroscopy, and quasiparticle corrected density functional theory calculations. The branch point energy in InN is experimentally determined to lie 1.83 +/- 0.10 eV above the valence-band maximum. This high position relative to the band edges is used to explain the extreme fundamental electronic properties of the material. Far from being anomalous, these properties are reconciled within chemical trends of common-cation and common-anion semiconductors.. ...
City Research Online - Electro-optical Plethysmography for Non-invasive Estimation of Hemoglobin Concentration
Novel sensors and instrumentation are currently being investigated with the intended application of determining the concentration of hemoglobin and other optically absorbing compounds in blood using non-invasive methods. In order to measure concentration, the mass or amount of a compound must be known in addition to the volume of liquid. In principle, it may be possible to estimate hemoglobin concentration from a change in optical absorbance occurring over the cardiac cycle divided by a corresponding change in measured blood volume during the cycle measured from peripheral tissue, e.g. the finger or ear. Electrical and optical sensors were evaluated in vitro using a tissue phantom and an absorbing liquid medium. The effect of changes in optical absorption and pulse pressure on the capacitance and optical absorbance were studied.. ...
Separation of certain components of human urine on columns of polysaccharide gels and isolation of substance absorbing at 260...
Lipid peroxidation, circulating cytokine and endothelin 1 levels in healthy volunteers undergoing hyperbaric oxygenation -...
Methods. Experimental design: single arm, prospective study. Setting: ICU hyperbaric division of a University Hospital. Patients: fifteen healthy volunteers (10 male and 5 female, mean age 32±7 years) studied during hyperbaric oxygenation divided at random into two groups: group A (7 subjects) and group B (8 subjects). Interventions: Both groups were consecutively pressurized at 2 atmospheres (2 atm abs) and 2.8 atm abs, with a constant descending rate of 1 m/min; in accordance with the experimental design, group A breathed pure oxygen continuously through facial masks and group B breathed chamber air during pressurization. Measures: Twenty millilitres of blood were drawn from all individuals at the following times: 1) basal, before HBO; 2) after 10 min at 2 atm abs; 3) after 10 min at 2.8 atm abs; 4) 30 min after the end of HBO. In all collected samples thiobarbituric reacting substances were evaluated, using the spectrophotometric technique, IL1 TNF and IL6 serum levels by ELISA and ...
Synthesis of Simple Sandwich Dyes - Cornell College Student Symposium
There is little that is known about organic dye aggregates because the size and geometry are difficult to control. This further complicates the comparison of the optical properties of the dye aggregate to its structure. The purpose of this research was to synthesize simple face to face organic dye aggregates and study their solubility and optical absorbance, and compare those results with the results of structurally similar dyes. Using a monomer that has been shown to readily form aggregates, complex dimer molecules were synthesized. The two monomer chains were connected via alkane chains of piperazine, which put a space of two carbons between each monomer chain. Each dye aggregate was in contact with another dye aggregate in a dilute solution, which permitted the comparison of single interactions and the resulting optical properties. The face to face dimer showed a lower energy, red shift in its optical absorbance when compared to that of the monomer. Molecula ...
IGEM:IMPERIAL/2009/Assays Protocols/Shopping - OpenWetWare
2) Start reactions with enzyme and stopped after set times (0, 4, 8, 12 minutes) by placing the tubes in boiling water for 2 min. 3) Add 0.9 ml 40 mM-HEPES/ KOH (pH 6-8) containing 10 mM-MgCl2, 2.5 mM-phosphoenolpyruvate and 0.24 mM-NADH 4) Centrifuge to remove precipitated protein, 5) Measure spectrophotometrically at 340 nm the disappearance of NADH on addition of pyruvate kinase and lactate dehydrogenase. When substrate concentrations were varied in TPS assays, rates at each concentration were measured over two different time intervals. They generally agreed within l0%, and the mean was used. However, when a significant amount of substrate was consumed ( ,15% at initial concentrations below Km), the rate from each time interval was handled separately and plotted against the average substrate concentration in the time interval, as recommended by Glick et al. (1979). ...
Thermo Scientific Evolution 300 UV-Vis Spectrophotometer:Spectrophotometers, | Fisher Scientific
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floatation spectrophotometry是什么意思 海词词典
RR and electronic absorption spectra of Fe-S clusters a | Open-i
Derivative spectrophotometric method for the determination of clarithromycin in pharmaceutical formulation and application to...
Cross section (physics)
However, recent guidelines suggest that spectrophotometry should be performed. Spectrophotometry relies on the different ... Spectrophotometry can also detect the presence of oxyhemoglobin and methemoglobin, which absorb light at 410-418 nm and 403-410 ... Chu, K; Hann, A; Greenslade, J; Williams, J; Brown, A (Mar 10, 2014). "Spectrophotometry or Visual Inspection to Most Reliably ... Its presence can be determined by either by spectrophotometry (measuring the absorption of particular wavelengths of light) or ...
Described as "famous" it gave the field of Raman spectrophotometry a "tremendous boost" in the United States. Other instruments ... Beckman, A. O.; Gallaway, W. S.; Kaye, W.; Ulrich, W. F. (1977). "History of spectrophotometry at Beckman Instruments, Inc". ... Hind, Andrew R. (December 2002). "To improvements in spectrophotometry. ." (PDF). American Laboratory. 34: 32-35. Retrieved 27 ... use single instrument containing both the optical and electronic components needed for ultraviolet-absorption spectrophotometry ...
Cary 14 Spectrophotometer
Clarke, F. J. J. (June 5, 1972). "High Accuracy Spectrophotometry at the National Physical Laboratory (Teddington, Middlesex, ... Hind, Andrew R. (December 2002). "To improvements in spectrophotometry. ." (PDF). American Laboratory. 34: 32-35. Retrieved 27 ... Sommer, L. (1989). Analytical absorption spectrophotometry in the visible and ultraviolet : the principles. Amsterdam: Elsevier ...
New Detailed GTC-OSIRIS spectrophotometry of Three Galaxies". They give the results for the deep broad-band imaging and long- ... OSIRIS spectrophotometry of three galaxies". The Astrophysical Journal. 749 (2): 185. arXiv:1202.3419v1 . Bibcode:2012ApJ...749 ... New detailed GTC-OSIRIS spectrophotometry of three galaxies" in which they presented the findings of observations carried out ...
List of quasars
Holger Pedersen (astronomer)
List of the most distant astronomical objects
Collimated transmission theory
Beck, Shane (February 2, 1998). "Across the Spectrum: Instrumentation for UV/Vis Spectrophotometry". The Scientist. Retrieved 9 ... "History of spectrophotometry at Beckman Instruments, Inc". Analytical Chemistry. 49 (3): 280A-300A. doi:10.1021/ac50011a001. ... use single instrument containing both the optical and electronic components needed for ultraviolet-absorption spectrophotometry ...
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Spectrophotometry - Wikipedia
Spectrophotometry is also a helpful process for protein purification and can also be used as a method to create optical assays ... Spectrophotometry is a tool that hinges on the quantitative analysis of molecules depending on how much light is absorbed by ... Samples for IR spectrophotometry may be smeared between two discs of potassium bromide or ground with potassium bromide and ... Largely, spectrophotometry is best used to help quantify the amount of purification your sample has undergone relative to total ...
Spectrophotometry | physics | Britannica.com
Spectrophotometry, branch of spectroscopy that deals with measurement of the radiant energy transmitted or reflected by a body ... Spectrophotometry, branch of spectroscopy that deals with measurement of the radiant energy transmitted or reflected by a body ... Spectrophotometry of protein solutions (the measurement of the degree of absorbance of light by a protein within a specified ... Infrared spectrophotometry is most commonly used in studying the molecular structures of complex organic compounds. ...
Micro-spectrophotometry | Encyclopedia.com
Source for information on Micro-spectrophotometry: World of Forensic Science dictionary. ... Micro-spectrophotometry Micro-spectrophotometry (MSP) is an essential tool in the forensic analysis of many kinds of trace ... Micro-spectrophotometry. Micro-spectrophotometry (MSP) is an essential tool in the forensic analysis of many kinds of trace ... www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/micro-spectrophotometry ...
Patent US4972331 - Phase modulated spectrophotometry - Google Patents
The application of the principles of dual wavelength spectrophotometry to time-resolved spectrophotometry involves the choice ... Patient Monitoring Using Combination of Continuous Wave Spectrophotometry and Phase Modulation Spectrophotometry. ... Phase modulated spectrophotometry. US5131391 *. May 31, 1990. Jul 21, 1992. Colin Electronics Co., Ltd.. Pulse oxymeter having ... It has now been found that the principles of dual wavelength spectrophotometry may be applied to time-resolved ...
Spectrophotometry | British Astronomical Association
Hi Kate,. I have one but have not used it "in anger". To produce a spectrum calibrated in absolute flux, two sets of spectra are taken, one as normal in the narrow slit, and one effectively "slitless" using the wider part.. The narrow slit spectrum has the fine detail and accurate wavelength calibration but only includes the fraction of flux which happens to pass through the slit so cannot be used to measure the absolute flux. The wide slit spectrum has lower resolution and poorer wavelength calibration but includes the total flux from the target. By combining the two a fully flux calibrated spectrum can be produced with accurate wavelength and good resolution. Christian Buils page here shows how to do this using ISIS.. http://www.astrosurf.com/buil/calibration2/absolute_calibration_en.htm. and an example of it in use (in French). http://www.astrosurf.com/buil/alpy600/photometric_slit.htm. The conventional photometric brightnesses can then be calculated by integrating the spectrum over the ...
Spectrophotometry | SDSS
The spectrophotometry since DR2 is vastly improved compared to DR1, but the final calibrated spectra in DR2 and beyond are not ... The spectrophotometry was tied to the fiber magnitudes of stars, whose relation to the true, PSF magnitudes of stars is seeing- ... The spectrophotometry is normalized to PSF magnitudes for point sources.. The spectrophotometric algorithms were improved ... over the survey is 0.034). Users of spectra should note that the fractional improvement in spectrophotometry from DR1 to DR2 ...
Spectrophotometry - Wikipedia
"Spectrophotometry". NIST. Retrieved Dec 23, 2018.. *^ a b c d e f g h i j Ninfa AJ, Ballou DP, Benore M (2010). Fundamental ... "Spectrophotometry Applications and Fundamentals". www.mt.com. Mettler-Toledo International Inc. Retrieved Jul 4, 2018.. ... UV-visible spectrophotometryEdit. Main article: Ultraviolet-visible spectroscopy. Most spectrophotometers are used in the UV ... IR spectrophotometryEdit. Main article: Infrared spectroscopy. Spectrophotometers designed for the infrared region are quite ...
High Resolution Low Temperature Spe ctrophotometry of Cyto chromes c | SpringerLink
Analytical Absorption Spectrophotometry in the Visible and Ultraviolet, Volume 8 - 1st Edition
Purchase Analytical Absorption Spectrophotometry in the Visible and Ultraviolet, Volume 8 - 1st Edition. Print Book & E-Book. ... Basis of Spectrophotometry in UV and VIS. 2. Principles of Instrumentation. 3. Errors in Spectrophotometry. 4. Evaluation of ... 7. Complexation and Spectrophotometry. 8. Some Applications of UV and VIS Spectrophotometry. Appendix. Subject Index. ... Analytical Absorption Spectrophotometry in the Visible and Ultraviolet, Volume 8 1st Edition. The Principles. 0.0 star rating ...
Intracellular pH determination by absorption spectrophotometry of neutral red | SpringerLink
Lee, H. C., Forte, J. G., and Epel, D. (1982). The use of fluorescent amines for the measurement of pH: Applications in liposomes, gastric microsomes, and sea urchin gametes. In Nuccitelli, R., and Deamer, D. W. (eds.),Intracellular pH: Its Measurement, Regulation, and Utilization in Cellular Functions, Alan R. Liss, New York, pp. 135-160.Google Scholar ...
Ultraviolet-Visible (UV-VIS) Spectrophotometry - Chemistry | Lycoming College
What is the basic principle of atomic absorption spectrophotometry? | Reference.com
Spectrophotometry is a technique used in measuring the quantity ... ... The basic principle of atomic absorption spectrophotometry states that atoms absorb specific wavelengths of electromagnetic ... Spectrophotometry is a useful tool in quantitative analysis where the concentration of a substance is to be identified. Atomic ... The basic principle of atomic absorption spectrophotometry states that atoms absorb specific wavelengths of electromagnetic ...
astrometry, COLLIMATORS, DWARF STARS, H ALPHA LINE, HEAO 1, LATE STARS, POSITION (LOCATION), Spectrophotometry, X RAY SOURCES ... astrometry, ENERGY SPECTRA, EXTRAGALACTIC RADIO SOURCES, QUASARS, RADIO ASTRONOMY, SEYFERT GALAXIES, Spectrophotometry, ... Spectrophotometry, SURFACE PROPERTIES, TEMPERATURE MEASUREMENT, texture, THERMAL PROPERTIES, ULTRAVIOLET, VISIBLE WAVELENGTHS ... Spectrophotometry, SPECTRUM ANALYSIS, Star formation, STELLAR LUMINOSITY, X RAY SOURCES ...
Reliability Of DNA Quantification By Spectrophotometry - QIAGEN
The concentration of nucleic acids in solution can be readily calculated from the absorbance at 260 nm. This figure shows the standard deviation of |em>A|/em>|sub>260|/sub> measurements for serial dilutions of DNA. Although |em>A|/em>|sub>260|/sub> values between 0.1 and 1.0 are very reproducible, |em>A|/em>|sub>260|/sub> readings |0.1 and |1.0 lead to considerably lower reproducibility. Furthermore, readings above 3.0 are incorrect, which can potentially leading to underestimation of the DNA quantity. Therefore, for reliable spectrophotometric DNA quantification, |em>A|/em>|sub>260 |/sub>readings should lie between 0.1 and 1.0. When working with small amounts of DNA, quantification by agarose gel electrophoresis may be more reliable. electrophoresis may be more reliable.
Spectrophotometry applications, fundamentals, and tips and tricks
Find out what are spectrophotometry applications, and how to use a UV/VIS spectrophotometer for precise and accurate ... Find out what are spectrophotometry applications, and how to use a UV/VIS spectrophotometer for precise and accurate ... Download our UV/VIS Spectrophotometry Applications guide now to benefit from best practices in Spectroscopy and to have a ... The UV/VIS Spectrophotometry guide provides the reader with fundamental knowledge on this technique as well as ...
Spectrophotometry UV/VIS for micro-volume samples
Spectrophotometry for UV/VIS micro-volume samples. Easy and accurate UV/VIS micro-volume spectrophotometry with only one drop ... Home Analytical Instruments Spectrophotometer UV Vis UV Vis Micro-Volume Spectrophotometry See all models. Request Info / ... OneDrop UV Vis Spectrophotometry. Only a minimal amount of sample is required for accurate measurements. Wide concentration ... Easy and accurate UV/VIS micro-volume spectrophotometry with only one drop of sample. A wide range of concentrations is covered ...
Spectrophotometry | Atlas
Microdetermination of Methenamine in the Presence of Formaldehyde by Solid Phase Spectrophotometry
LC/MS Spectrophotometry | Laboratory Talk
Spectrophotometry- NADH absorbance? - General Lab Techniques
Spectro-photometry of Neptune 20149/08/22 - Observational Astrophysics - Cloudy Nights
Determining an Equilibrium Constant Using Spectrophotometry | Rent 9780875403434 | 0875403433
SPECTROPHOTOMETRY OF ATMOSPHERIC EMISSIONS.
A scanning spectrophotometer equipped with a S-1 sensitive photomultiplier has been used to obtain auroral spectra in the wavelength region 6400A to 9700A. Emissions of neutrol and singly ionized molecular nitrogen, molecular oxygen, hydroxyl, and atomic lines of oxygen and nitrogen were recorded with 10 second scan times and 20 A resolution. A comparison of the relative intensities of several vibration bands of the N2 1PG system averaged over several scans with theoretical intensities and previously observed intensities reveals no evidence of selective excitation. A similar analysis of the Meinel N+2 bands also shows no evidence of selective excitation except possibly for the (1-0) band which seems enhanced on many spectra. The observations show that hydroxyl emissions are definitely associated with aurora. The association is not a direct one. There is a time lag of a few seconds between the brightening of the aurora and the enhancement of OH emissions. Similarly the OH emissions decay much more
Spectrophotometry, Infrared | Harvard Catalyst Profiles | Harvard Catalyst
Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption ... "Spectrophotometry, Infrared" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH ( ... This graph shows the total number of publications written about "Spectrophotometry, Infrared" by people in Harvard Catalyst ... Below are the most recent publications written about "Spectrophotometry, Infrared" by people in Profiles. ...
Estimation of the galanthamine using derivative spectrophotometry in bulk drug and formulation
First method is zero order UV spectrophotometry and second is 1st derivative zero crossing spectrophotometry. The developed ... First method is zero order UV spectrophotometry and second is 1st derivative zero crossing spectrophotometry. The developed ... alanthamine Hydrobromide (GH); Zero Order UV-Spectrophotometry; First Derivative Zero Crossing Spectrophotometry ... Mittal, K. , Kaushal, R. , Mashru, R. and Thakkar, A. (2010) Estimation of the galanthamine using derivative spectrophotometry ...
Derivative Spectrophotometry and Electron Spin Resonance (ESR) Spectroscopy for Ecological and Biological Questions | Vladimir...
This book provides a multidisciplinary overview to the application of high order derivative spectrophotometry and Electron Spin ... Derivative Spectrophotometry and Electron Spin Resonance (ESR) Spectroscopy for Ecological and Biological Questions. Authors. * ... Derivative Spectrophotometry and Electron Spin Resonance (ESR) Spectroscopy for Ecological and Biological Questions. Authors: ... This book provides a multidisciplinary overview to the application of high order derivative spectrophotometry and Electron Spin ...
ASTM D4691 - 17 Standard Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry
D4691-17 Standard Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry flame atomic absorption ... Flame atomic absorption spectrophotometry is simple, rapid, and applicable to a large number of elements in drinking water, ... Standard Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry. Active Standard ASTM D4691 , ... ASTM D4691-17, Standard Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry, ASTM ...
ASTM C1307 - 15 Standard Test Method for Plutonium Assay by Plutonium (III) Diode Array Spectrophotometry
... diode array spectrophotometry, plutonium assay, spectrophotometry (of plutonium (III)) ,, ... Standard Test Method for Plutonium Assay by Plutonium (III) Diode Array Spectrophotometry. Active Standard ASTM C1307 , ... ASTM C1307-15, Standard Test Method for Plutonium Assay by Plutonium (III) Diode Array Spectrophotometry, ASTM International, ...
Spectrophotometry: Technique To Determine The Chemical... | Major Tests
Spectrophotometry: Technique to determine the chemical composition and concentration of sample. The... ... Spectrophotometry: Technique To Determine The Chemical Composition And Concentration Of Lab. Submitted By amaltmann ... Spectrophotometry: Technique to determine the chemical composition and concentration of sample. The spectrophotometer: ...
Spectrophotometry of Artemisia tridentata to quantitatively determine subspecies
In this study, we use spectrophotometry to quantify chemical differences in the water-soluble compound, coumarin. Ultraviolet ( ... Use of spectrophotometry to acquire UV absorbance provides empirical results that can be used in seed testing laboratories ... Spectrophotometry of Artemisia tridentata to quantitatively determine subspecies. Series title. Rangeland Ecology and ... Spectrophotometry of Artemisia tridentata to quantitatively determine subspecies. Rangeland Ecology and Management ...
Derivative spectrophotometrySpectroscopyUltravioletParticle size affect spectrophotometryWavelengthSpectrophotometerMicro-volume spectrophotometryChemistryConcentrationAbsorptionWavelengthsFluorescence SpectrophotometryMeasurementAbsorbanceSpectrophotometricQuantifyHPLCSpectrumQuantitative analysisMethodLaboratoryReagentDiagnosisDevelopment and ValidationAnalysisMethodsNitriteWaterTraceConcentrationsVisibleSubduralMonitoringSimultaneouslyApplications
- This book provides a multidisciplinary overview to the application of high order derivative spectrophotometry and Electron Spin Resonance (ESR) spectroscopy in biology and ecology. (springer.com)
- Ansary A, Abdel-Moety MM, Abdel-Gawad FM, Mohamed EA, Khater MM (2012) Simultaneous Determination of Carvedilol and Hydrochlorothiazide in Tablets and Spiked Human Plasma using Derivative Spectrophotometry. (omicsonline.org)
- The first method is the application of derivative spectrophotometry where the linearity range and percentage recoveries for DOM and CINN were 2.5â€"30 Âµg mLâ€"1, 5â€"25 Âµg mLâ€"1 and 100.06Â±1.157, 99.93Â±1.377, respectively. (ebscohost.com)
- Derivative spectrophotometry (DS) is an advanced, modern spectrophotometric technique. (thefreedictionary.com)
- Simultaneous determination of lamivudine and stavudine in antiretroviral fixed dose combinations by first derivative spectrophotometry and high performance liquid chromatography. (thefreedictionary.com)
- It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared, but does not cover time-resolved spectroscopic techniques. (wikipedia.org)
- Spectrophotometry , branch of spectroscopy that deals with measurement of the radiant energy transmitted or reflected by a body as a function of the wavelength. (britannica.com)
- Ultraviolet spectrophotometry is particularly useful in detecting colourless substances in solution and measuring their concentration. (britannica.com)
- Moreover, the method and its instrumentation has recently undergone considerable development resulting in some new special approaches of spectrophotometry in the ultraviolet (UV) and visible (VIS) regions. (elsevier.com)
- Ultraviolet-Visible Spectrophotometry (UV-VIS) is useful for both quantitative and qualitative work. (lycoming.edu)
- Ultraviolet spectrophotometry is used to show the presence of rosin or ester gum modifications in the unsaponifiable portion of an isolated alkyd coating vehicle. (dtic.mil)
- The first method is based on the first derivative ( D) ultraviolet spectrophotometry, with zero crossing and peak to base measurement. (ebscohost.com)
- For ultraviolet-visible spectrophotometry , their linearity ranges were observed to be 0. (thefreedictionary.com)
Particle size affect spectrophotometry1
- In chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. (wikipedia.org)
- Spectrophotometry uses photometers, known as spectrophotometers, that can measure a light beam's intensity as a function of its color (wavelength). (wikipedia.org)
- In astronomy, the term spectrophotometry refers to the measurement of the spectrum of a celestial object in which the flux scale of the spectrum is calibrated as a function of wavelength, usually by comparison with an observation of a spectrophotometric standard star, and corrected for the absorption of light by the Earth's atmosphere. (wikipedia.org)
- Colloidal metal NP size can also be assessed using UV-Vis spectrophotometry, as the wavelength of the absorbance peak is dependent on the size and shape of the particles because of the surface plasmon resonance effect as light strikes them. (labmanager.com)
- Therefore, we designed and developed a spectrophotometer which would afford students the opportunity to discover and understand the concepts of spectrophotometry. (scielo.org.za)
- In the current study, we compared COHb results obtained with automated CO-oximetry (Diametrics Medical AVOX 4000) and manual UV spectrophotometry (Hewlett Packard 8453 UV spectrophotometer) (8). (thefreedictionary.com)
- Despite the existence of many competitive analytical techniques, molecular absorption spectrophotometry still remains very popular in practice, particularly in biochemical, clinical, organic, agricultural, food and environmental analyses. (elsevier.com)
- What is the basic principle of atomic absorption spectrophotometry? (reference.com)
- The basic principle of atomic absorption spectrophotometry states that atoms absorb specific wavelengths of electromagnetic radiation. (reference.com)
- Atomic absorption spectrophotometry assays the metal content in water. (reference.com)
- Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (harvard.edu)
- Currently, one of the most widely used and practical means for measuring concentrations of elements is by atomic absorption spectrophotometry. (astm.org)
- 1.1 This practice covers general considerations for the quantitative determination of elements in water and waste water by flame atomic absorption spectrophotometry. (astm.org)
- Flame atomic absorption spectrophotometry is simple, rapid, and applicable to a large number of elements in drinking water, surface waters, and domestic and industrial wastes. (astm.org)
- Comparison of the determination of magnesium by methylthymol blue spectrophotometry and atomic absorption spectrophotometry. (sigmaaldrich.com)
- Plasma samples (n = 155) of 30 patients on an intensive ward were analysed for magnesium simultaneously by atomic absorption spectrophotometry (AAS) and methylthymol blue spectrophotometry. (sigmaaldrich.com)
- There are also several variations of the spectrophotometry such as atomic absorption spectrophotometry and atomic emission spectrophotometry. (libretexts.org)
- In visible spectrophotometry, the absorption or the transmission of a certain substance can be determined by the observed color. (libretexts.org)
- The validity of atomic absorption spectrophotometry Ior measuring markers of trapped volume was checked by comparative determinations of markers with established optical spectrophotometrical methods. (bioscirep.org)
- Spectrophotometry is a chemical technique which measures the reflection or transmission in wavelengths of a material. (elgalabwater.com)
- Cavity-enhanced laser spectrophotometry is performed on analytes within a microfluidic channel at visible wavelengths with silicon nitride microring resonators of 100 µm radius and quality factor of ~180,000. (osapublishing.org)
- The spectrophotometry was taken with the Keck I/Low Resolution Imaging Spectrometer between wavelengths 434 and 912 nm in the B, g, V, R, I, and RG850 filters as it was leaving the Earth-Moon system on 2020 March 23 UTC. (caltech.edu)
- Due to the nature of spectrophotometry , a given liquid will have different levels of absorbency at different wavelengths. (thefreedictionary.com)
- The paper reviewed the application these years of fluorescence spectrophotometry in environmental monitoring.The content includes the principle,the establishment of methods,the study of fluorescence system and the development of the combination with other techniques. (cnki.com.cn)
- In this study, we use spectrophotometry to quantify chemical differences in the water-soluble compound, coumarin. (usgs.gov)
- Our study aimed to quantify assay-based variation in G6PD spectrophotometry and to explore the diagnostic implications of applying a universal threshold. (malariaconsortium.org)
- Although there are a number of comprehensive textbooks dealing with UV/VIS spectrophotometry, they tend to describe historical aspects or contain collections of detailed procedures for the determination of analytes and do not reflect sufficiently the present state of the method and stage of development reached. (elsevier.com)
- First method is zero order UV spectrophotometry and second is 1st derivative zero crossing spectrophotometry. (scirp.org)
- In conclusion, CSF spectrophotometry is a simple, fast, and extremely sensitive method, which in our opinion should be used routinely in the diagnosis of suspected subdural haematomas, if lumbar puncture is not contraindicated. (bmj.com)
- A new method for rapid determination of carbohydrate and total carbon concentrations using UV spectrophotometry. (nih.gov)
- Spectrophotometry is a method to measure how much a chemical substance absorbs light by measuring the intensity of light as a beam of light passes through sample solution. (libretexts.org)
- A vortex-assisted liquid-liquid microextraction (VALLME) method using isooctanol as extractant followed by spectrophotometry was developed for the extraction and determination of trace nitrite in water samples. (iwaponline.com)
- This description provides a system and a method to analyze spectrophotometry and ultrasound images and data in a complex way in order to diagnose malignant skin tumors in early stages. (sumobrain.com)
- The book is written for all those who use UV/VIS spectrophotometry in the laboratory and will also be useful to students as supplementary reading. (elsevier.com)
- Extend the capabilities of your laboratory and get reliable analytical results in applications such as spectrophotometry and element analysis , with products from Avantor Performance Materials. (avantorinc.com)
Development and Validation2
- Development and Validation of Chemometrics-Assisted Spectrophotometry and Liquid Chromatography Methods for the Simultaneous Determination of the Active Ingredients in Two Multicomponent Mixtures Containing Chiorpheniramine Maleate and. (ebscohost.com)
- The article describes the development and validation of chemometrics-assisted spectrophotometry and liquid chromatography (LC) methods for the simultaneous analysis of the active ingredients in two multicomponent mixtures containing chlorpheniramine maleate and phenylpropanolamine hydrochloride. (ebscohost.com)
- The significance of spectrophotometry in connection with liquid-liquid extraction, reaction kinetics, trace analysis, environmental and clinical analysis is also covered. (elsevier.com)
- We offer a complete line of Thermo Scientific colorimetry, turbidity, and UV-Vis spectrophotometry meters for water and wastewater analysis. (thermofisher.com)
- Trace amount of Hg co precipitated with Cu 2HgI 4 and Cu 2I 2 was determined by use of solid phase reflection diffuse spectrophotometry. (cnki.com.cn)
- In order to determine the respective concentrations of reactants and products at this point, the light transmittance of the solution can be tested using spectrophotometry. (wikipedia.org)
- Spectrophotometry is often used in measurements of enzyme activities, determinations of protein concentrations, determinations of enzymatic kinetic constants, and measurements of ligand binding reactions. (wikipedia.org)
- 8. Some Applications of UV and VIS Spectrophotometry. (elsevier.com)
- UV/VIS Spectrophotometry Applications Guide - free download. (mt.com)
- The UV/VIS Spectrophotometry guide provides the reader with fundamental knowledge on this technique as well as spectrophotometry applications , and tips and tricks for accurate and precise results in daily use. (mt.com)
- Here are the requirements for spectrophotometry applications. (elgalabwater.com)