Acid-Base Equilibrium: The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.Acid-Base Imbalance: Disturbances in the ACID-BASE EQUILIBRIUM of the body.Base Pairing: Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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)Kinetics: The rate dynamics in chemical or physical systems.Cytosine: A pyrimidine base that is a fundamental unit of nucleic acids.Nucleic Acids: High molecular weight polymers containing a mixture of purine and pyrimidine nucleotides chained together by ribose or deoxyribose linkages.GuanineCarbocysteine: A compound formed when iodoacetic acid reacts with sulfhydryl groups in proteins. It has been used as an anti-infective nasal spray with mucolytic and expectorant action.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)Alkalosis: A pathological condition that removes acid or adds base to the body fluids.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Hydrogen Bonding: A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.Purines: A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.Acidosis: A pathologic condition of acid accumulation or depletion of base in the body. The two main types are RESPIRATORY ACIDOSIS and metabolic acidosis, due to metabolic acid build up.Adenine: A purine base and a fundamental unit of ADENINE NUCLEOTIDES.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Bicarbonates: Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.Alkalies: Usually a hydroxide of lithium, sodium, potassium, rubidium or cesium, but also the carbonates of these metals, ammonia, and the amines. (Grant & Hackh's Chemical Dictionary, 5th ed)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.Alkalosis, Respiratory: A state due to excess loss of carbon dioxide from the body. (Dorland, 27th ed)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.DNA, B-Form: The most common form of DNA found in nature. It is a right-handed helix with 10 base pairs per turn, a pitch of 0.338 nm per base pair and a helical diameter of 1.9 nm.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).Xanthopterin: 2-Amino-1,5-dihydro-4,6-pteridinedione. Pigment first discovered in butterfly wings and widely distributed in plants and animals.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Education, Veterinary: Use for general articles concerning veterinary medical education.Sodium Bicarbonate: A white, crystalline powder that is commonly used as a pH buffering agent, an electrolyte replenisher, systemic alkalizer and in topical cleansing solutions.Hypermedia: Computerized compilations of information units (text, sound, graphics, and/or video) interconnected by logical nonlinear linkages that enable users to follow optimal paths through the material and also the systems used to create and display this information. (From Thesaurus of ERIC Descriptors, 1994)UracilMagnetic 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).Schiff Bases: Condensation products of aromatic amines and aldehydes forming azomethines substituted on the N atom, containing the general formula R-N:CHR. (From Grant & Hackh's Chemical Dictionary, 5th ed)Skull Base: The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.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.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Acids: Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water. (Grant & Hackh's Chemical Dictionary, 5th ed)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).Nucleic Acid Denaturation: Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Gases: The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)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)ThymineTemperature: 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.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.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Molecular Conformation: The characteristic three-dimensional shape of a molecule.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.Catalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.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)Physiology: The biological science concerned with the life-supporting properties, functions, and processes of living organisms or their parts.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.Xylosidases: A group of enzymes that catalyze the hydrolysis of alpha- or beta-xylosidic linkages. EC 3.2.1.8 catalyzes the endo-hydrolysis of 1,4-beta-D-xylosidic linkages; EC 3.2.1.32 catalyzes the endo-hydrolysis of 1,3-beta-D-xylosidic linkages; EC 3.2.1.37 catalyzes the exo-hydrolysis of 1,4-beta-D-linkages from the non-reducing termini of xylans; and EC 3.2.1.72 catalyzes the exo-hydrolysis of 1,3-beta-D-linkages from the non-reducing termini of xylans. Other xylosidases have been identified that catalyze the hydrolysis of alpha-xylosidic bonds.Histidine: An essential amino acid that is required for the production of HISTAMINE.beta-Glucosidase: An exocellulase with specificity for a variety of beta-D-glycoside substrates. It catalyzes the hydrolysis of terminal non-reducing residues in beta-D-glucosides with release of GLUCOSE.Biocatalysis: The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Ammonium Chloride: An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating.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.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Dialysis: A process of selective diffusion through a membrane. It is usually used to separate low-molecular-weight solutes which diffuse through the membrane from the colloidal and high-molecular-weight solutes which do not. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.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.Hydrogen: The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.PolynucleotidesDNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Glycoside HydrolasesElectrons: 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.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.RNA: A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.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)Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Ultracentrifugation: Centrifugation with a centrifuge that develops centrifugal fields of more than 100,000 times gravity. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Bacterial Proteins: Proteins found in any species of bacterium.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.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).Cysteine: A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.Pyrimidines: A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.Skull Base Neoplasms: Neoplasms of the base of the skull specifically, differentiated from neoplasms of unspecified sites or bones of the skull (SKULL NEOPLASMS).Base Pair Mismatch: The presence of an uncomplimentary base in double-stranded DNA caused by spontaneous deamination of cytosine or adenine, mismatching during homologous recombination, or errors in DNA replication. Multiple, sequential base pair mismatches lead to formation of heteroduplex DNA; (NUCLEIC ACID HETERODUPLEXES).Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.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)Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.Denture Bases: The part of a denture that overlies the soft tissue and supports the supplied teeth and is supported in turn by abutment teeth or the residual alveolar ridge. It is usually made of resins or metal or their combination.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.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.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Guanidine: A strong organic base existing primarily as guanidium ions at physiological pH. It is found in the urine as a normal product of protein metabolism. It is also used in laboratory research as a protein denaturant. (From Martindale, the Extra Pharmacopoeia, 30th ed and Merck Index, 12th ed) It is also used in the treatment of myasthenia and as a fluorescent probe in HPLC.Molecular Weight: The sum of the weight of all the atoms in a molecule.Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.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.Calorimetry: The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)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.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Chemistry, Physical: The study of CHEMICAL PHENOMENA and processes in terms of the underlying PHYSICAL PHENOMENA and processes.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Physicochemical Phenomena: The physical phenomena describing the structure and properties of atoms and molecules, and their reaction and interaction processes.Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.Protein Structure, Secondary: The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.Oligodeoxyribonucleotides: A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Nuclear Magnetic Resonance, Biomolecular: NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.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.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Allosteric Regulation: The modification of the reactivity of ENZYMES by the binding of effectors to sites (ALLOSTERIC SITES) on the enzymes other than the substrate BINDING SITES.Oligonucleotides: Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Biophysical Phenomena: The physical characteristics and processes of biological systems.Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.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.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.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.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Nucleotides: The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Protein Structure, Quaternary: The characteristic 3-dimensional shape and arrangement of multimeric proteins (aggregates of more than one polypeptide chain).Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Gene Frequency: The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.Muscles: Contractile tissue that produces movement in animals.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.Knowledge Bases: Collections of facts, assumptions, beliefs, and heuristics that are used in combination with databases to achieve desired results, such as a diagnosis, an interpretation, or a solution to a problem (From McGraw Hill Dictionary of Scientific and Technical Terms, 6th ed).Adsorption: The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Isomerism: The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Mannich Bases: Ketonic amines prepared from the condensation of a ketone with formaldehyde and ammonia or a primary or secondary amine. A Mannich base can act as the equivalent of an alpha,beta unsaturated ketone in synthesis or can be reduced to form physiologically active amino alcohols.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.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)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.Genetic Variation: Genotypic differences observed among individuals in a population.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.DNA Glycosylases: A family of DNA repair enzymes that recognize damaged nucleotide bases and remove them by hydrolyzing the N-glycosidic bond that attaches them to the sugar backbone of the DNA molecule. The process called BASE EXCISION REPAIR can be completed by a DNA-(APURINIC OR APYRIMIDINIC SITE) LYASE which excises the remaining RIBOSE sugar from the DNA.Phosphates: Inorganic salts of phosphoric acid.DNA Repair: The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.Anilino Naphthalenesulfonates: A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Genetics, Population: The discipline studying genetic composition of populations and effects of factors such as GENETIC SELECTION, population size, MUTATION, migration, and GENETIC DRIFT on the frequencies of various GENOTYPES and PHENOTYPES using a variety of GENETIC TECHNIQUES.2-Aminopurine: A purine that is an isomer of ADENINE (6-aminopurine).Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Diffusion: The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Fluorescence Polarization: Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.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)Molecular Dynamics Simulation: A computer simulation developed to study the motion of molecules over a period of time.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Protein Multimerization: The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.Salts: Substances produced from the reaction between acids and bases; compounds consisting of a metal (positive) and nonmetal (negative) radical. (Grant & Hackh's Chemical Dictionary, 5th ed)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)Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.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.Hemoglobin A: Normal adult human hemoglobin. The globin moiety consists of two alpha and two beta chains.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.Photolysis: Chemical bond cleavage reactions resulting from absorption of radiant energy.Ions: An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.Polymorphism, Genetic: The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.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)Sodium Chloride: A ubiquitous sodium salt that is commonly used to season food.Cross-Linking Reagents: Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.Diphosphoglyceric AcidsEnergy Transfer: The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Enzymes: Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Biopolymers: Polymers synthesized by living organisms. They play a role in the formation of macromolecular structures and are synthesized via the covalent linkage of biological molecules, especially AMINO ACIDS; NUCLEOTIDES; and CARBOHYDRATES.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Models, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Static Electricity: The accumulation of an electric charge on a objectLipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Photochemistry
(1/1073) Hyaline membrane disease, alkali, and intraventricular haemorrhage.

The relation between intraventricular haemorrhage (IVH) and hyaline membrane disease (HMD) was studied in singletons that came to necropsy at Hammersmith Hospital over the years 1966-73. The incidence of IVH in singleton live births was 3-22/1000 and of HMD 4-44/1000. Although the high figures were partily due to the large number of low birthweight infants born at this hospital, the incidence of IVH in babies weighing 1001-1500 g was three times as great as that reported in the 1658 British Perinatal Mortality Survey. Most IVH deaths were in babies with HMD, but the higher frequency of IVH was not associated with any prolongation of survival time of babies who died with HMD as compared with the 1958 survey. IVH was seen frequently at gestations of up to 36 weeks in babies with HMD but was rare above 30 weeks' gestation in babies without HMD. This indicated that factors associated with HMD must cause most cases of IVH seen at gestations above 30 weeks. Comparison of clinical details in infants with HMD who died with or without IVH (at gestations of 30-37 weeks) showed no significant differences between the groups other than a high incidence of fits and greater use of alkali therapy in the babies with IVH. During the 12 hours when most alkali therapy was given, babies dying with IVD received a mean total alkali dosage of 10-21 mmol/kg and those dying without IVH 6-34 mmol/kg (P less than 0-001). There was no difference in severity of hypoxia or of metabolic acidosis between the 2 groups. Babies who died with HMD and germinal layer haemorrhage (GLH) without IVH had received significantly more alkali than those who died with HMD alone, whereas survivors of severe respiratory distress syndrome had received lower alkali doses than other groups. It is suggested that the greatly increased death rate from IVH in babies with HMD indicates some alteration of management of HMD (since 1958) as a causative factor. Liberal use of hypertonic alkali solutions is the common factor which distinguishes babies dying with GLH and IVH from other groups of babies with HMD. Although the causal nature of this association remains unproved, it seems justifiable to lrge caution in alkali usage.  (+info)

(2/1073) Modeling the effects of proteins on pH in plasma.

Stewart's model of plasma acid-base balance (Can. J. Physiol. Pharmacol. 61: 1444-1461, 1983) has three weaknesses in the treatment of weak acids: 1) the combination of all weak acids into one entity, 2) inappropriate chemistry for the protein combination with H+, and 3) undocumented values for the dissociation parameters. The present study models serum albumin acid-base properties by fixed negative charges and the association of H+ with the imidazole side chain of histidine. This model has three parameters: 1) the net negative fixed charge (21 eq/mol), 2) the number of histidine residues (16/mol), and 3) the association constant for the imidazole side chain (1.77 x 10(-7) eq/l), all determined from published values. The model was compared with that of Figge, Mydosh, and Fencl (J. Lab. Clin. Med. 120: 713-719, 1992) and with the pH data of Figge, Rossing, and Fencl (J. Lab. Clin. Med. 117: 453-467, 1991). The predictions of pH were excellent, comparable to those found by Figge, Mydosh, and Fencl. The model has the advantages that its structure and parameter values are supported by the literature and that the acid-base effects of factors modifying protein can be investigated.  (+info)

(3/1073) Cardiovascular and catecholamine responses during endovascular and conventional abdominal aortic aneurysm repair.

OBJECTIVES: To compare changes in plasma catecholamines, acid-base status and cardiovascular dynamics in patients undergoing endovascular or conventional infrarenal abdominal aortic aneurysm (AAA) repair under standard general anaesthesia. DESIGN: Prospective cohort study. MATERIALS: 30 patients scheduled for elective infrarenal AAA repair. METHODS: Plasma epinephrine and norepinephrine concentrations, acid-base status and cardiovascular measurement were compared before surgery, and 5 min after aortic clamping and clamp release (conventional group) or occlusion and release (endovascular group) in patients undergoing endovascular (n = 15) or conventional AAA repair (n = 15). RESULTS: Arterial pH (p < 0.005) and base deficit (p < 0.05) increased, and plasma bicarbonate decreased (p < 0.005) during aortic cross-clamping in the conventional group. pH decreased further (p < 0.005), and base deficit and pCO2 increased (both p < 0.005) after clamp release. These changes were significantly greater than during endovascular repair, in whom within-group changes were not statistically significant. Values were similar in the two groups 30 min after reperfusion. Plasma epinephrine concentrations increased during conventional surgery (p < 0.05) and were greater than in the endovascular group (p < 0.05). Plasma norepinephrine concentrations increased during surgery in both groups but the changes were not statistically significant. CONCLUSIONS: Plasma catecholamine concentrations, changes in cardiovascular variables and acid-base status were increased during conventional compared with endovascular AAA repair.  (+info)

(4/1073) Benzodiazepine localisation at the lipid-water interface: effect of membrane composition and drug chemical structure.

The effect of membrane chemical composition and drug chemical structure on the localisation of several benzodiazepines (BZDs) (DZ, diazepam; CZ, clonazepam; CX, chlordiazepoxide) within model membranes was investigated. We used a spectrophotometric method presented in a previous paper (B.A. Garcia, M.A. Perillo, Biochim. Biophys. Acta 1324 (1997) 76-84) based on the study of BZD acid-base equilibrium. 'Intrinsic pK' values (pKi) were calculated according to the theory of M.S. Fernandez and P. Fromherz (J. Phys. Chem. 81 (1977) 1755-1761). Homogeneous media of known dielectric constant (dioxane 0-80% v/v in water) were used to construct a curve of DeltapKi (pKi-pKw) vs. dielectric constant (D) where DeltapKi values obtained in lipidic dispersions were interpolated. In heterogeneous media consisting of aqueous dispersions of Triton X-100 micelles we determined the relative localisation depth of BZDs according to their DTriton values (36, 37 and 62 for DZ, CX and CZ respectively) taking into account that lower D values correspond to deeper localisation. pKi determined in dispersions of dipalmitoylphosphatidylcholine (dpPC) and egg phosphatidylcholine (egg-PC) mixed multilamellar vesicles showed that, when cholesterol content increased from 0 to 20 mole%, D values decreased (from 59 to 40) in dpPC vesicles and increased (from 51 to 72) in egg-PC vesicles, indicating a tendency of BZDs to penetrate deeper into less ordered interfaces. These results should be considered to understand the non-specific pharmacological effects of BZDs as well as to evaluate the actual relevance of their pharmacological concentrations.  (+info)

(5/1073) Changes in ionized calcium concentrations and acid-base status during abdominal aortic vascular surgery.

Abdominal aortic surgery may produce significant haemodynamic instability (from a combination of factors: hypovolaemia, acid-base disturbances, vasoactive metabolite release from ischaemic tissues and hypocalcaemia). Calcium is often given after aortic unclamping to attenuate this instability. We studied 20 patients undergoing elective abdominal aortic surgery and observed a triphasic change in ionized calcium concentrations and acid-base status. Initially, during the cross-clamp period (when patients were cardiovascularly stable), ionized calcium concentrations decreased significantly (mean 1.06 (SD 0.08) to 0.91 (0.13) mmol litre-1; P < 0.01), while a significant metabolic acidosis developed (pH 7.38 (0.05) to 7.30 (0.05); P < 0.05). Second, release of the aortic cross-clamp resulted in further acidosis (pH 7.27 (0.05) (P < 0.05) mixed respiratory and metabolic) with a decrease in mean arterial pressure, with no change in ionized calcium concentrations. The third phase was associated with spontaneous restoration of acid-base status and ionized calcium concentrations to normal over 2 h. There was no correlation between units of blood given, volume of blood lost, fluid volume given or duration of aortic cross-clamping and degree of ionized hypocalcaemia. We conclude that ionized hypocalcaemia occurred during the cross-clamp period of aortic surgery, was unrelated to the volume of blood given and did not appear to be responsible for the changes in arterial pressure during surgery.  (+info)

(6/1073) Regulation of thick ascending limb ion transporter abundance in response to altered acid/base intake.

Changes in ammonium excretion with acid/base perturbations are dependent on changes in medullary ammonium accumulation mediated by active NH4+ absorption by the medullary thick ascending limb. To investigate whether alterations in the abundance of medullary thick ascending limb ion transporters, namely the apical Na+/K+(NH4+)/2Cl- -cotransporter (BSC-1), the apical Na+/H+ -exchanger (NHE3), and the Na+/K+ -ATPase alpha1-subunit, may be responsible in part for altered medullary ammonium accumulation, semiquantitative immunoblotting studies were performed using homogenates from the inner stripe of the rat renal outer medulla. After 7 d of NH4Cl (7.2 mmol/220 g body wt per d) loading (associated with increased medullary ammonium accumulation), neither BSC-1 nor Na+/K+ -ATPase protein expression was altered, but NHE3 protein abundance was significantly increased. On the other hand, both BSC-1 and Na+/K+ -ATPase protein abundance was increased significantly in rats fed NaHCO3 (7.2 mmol/220 g body wt per d) for 7 d. Rats fed a high-NaCl diet (7.7 mEq Na+/220 g body wt per d) for 5 d also showed marked increases in both BSC-1 and Na+/K+ -ATPase expression. The expression level of NHE3 protein did not change with either NaHCO3 or high NaCl intake. None of these three transporters showed a significant difference in abundance between the groups fed equimolar (7.2 mmol/220 g body wt per d for 7 d) NaHCO3 or NaCl. It is concluded that outer medullary BSC-1 and Na+/K+ -ATPase alpha1-subunit protein abundance is increased by chronic Na+ loading but not by acid/base perturbations and that outer medullary NHE3 protein abundance is increased by chronic NH4Cl loading.  (+info)

(7/1073) VCO2 and VE kinetics during moderate- and heavy-intensity exercise after acetazolamide administration.

The effect of carbonic anhydrase inhibition with acetazolamide (Acz) on CO2 output (VCO2) and ventilation (VE) kinetics was examined during moderate- and heavy-intensity exercise. Seven men [24 +/- 1 (SE) yr] performed cycling exercise during control (Con) and Acz (10 mg/kg body wt iv) sessions. Each subject performed step transitions (6 min) in work rate from 0 to 100 W [below ventilatory threshold (VET)]. VE and gas exchange were measured breath by breath. The time constant (tau) was determined for exercise VET by using a three-component model (fit from the start of exercise). VCO2 kinetics were slower in Acz (VET, MRT = 75 +/- 10 s) than Con (VET, MRT = 54 +/- 7 s). During VET kinetics were faster in Acz (MRT = 85 +/- 17 s) than Con (MRT = 106 +/- 16 s). Carbonic anhydrase inhibition slowed VCO2 kinetics during both moderate- and heavy-intensity exercise, demonstrating impaired CO2 elimination in the nonsteady state of exercise. The slowed VE kinetics in Acz during exercise +info)

(8/1073) Acid-base disturbance during hemorrhage in rats: significant role of strong inorganic ions.

The present study tests the hypothesis that changes in the strong inorganic ion concentrations contribute significantly to the acid-base disturbance that develops during hemorrhage in the arterial plasma of rats in addition to lactate concentration ([Lac-]) increase. The physicochemical origins for this acid-base disorder were studied during acute, graded hemorrhage (10, 20, and 30% loss of blood volume) in three groups of rats: conscious, anesthetized with ketamine, and anesthetized with urethan. The results support the hypothesis examined: strong-ion difference (SID) decreased in the arterial plasma of all groups studied because of an early imbalance in the main strong inorganic ions during initial hemorrhagic phase. Moreover, changes in plasma [Lac-] contributed to SID decrease in a later hemorrhagic phase (after 10% hemorrhage in urethan-anesthetized, after 20% hemorrhage in ketamine-anesthetized, and after 30% hemorrhage in conscious group). Inorganic ion changes were due to both dilution of the vascular compartment and ion exchange with extravascular space and red blood cells, as compensation for blood volume depletion and hypocapnia. Nevertheless, anesthetized rats were less able than conscious rats to preserve normal arterial pH during hemorrhage, mainly because of an impaired peripheral tissue condition and incomplete ventilatory compensation.  (+info)

*  Delta ratio
... a mixed acid - base metabolic acidosis. Result 3: if there is a pure HAGMA, you would expect the bicarb to fall at a similar ... So the AG doesn't change; but to maintain electrical equilibrium, if [Cl¯] goes up, [HCO3¯] must come down. Hence, ... the delta ratio will be close to zero and there is no mixed acid-base disorder. Your calculations can stop here. A normal anion ... Results 2 and 4 are the ones which have mixed acid-base disorders. Results 1. and 4. are oddities, mathematically speaking: ...
*  Bicarbonate buffer system
Oxtoby, David W.; Gillis, Pat (2015). "Acid-base equilibria". Principles of Modern Chemistry (8 ed.). Boston, MA: Cengage ... The bicarbonate buffer system is an acid-base homeostatic mechanism involving the balance of carbonic acid (H2CO3), bicarbonate ... and its conjugate base (for example, HCO− 3) so that any excess acid or base introduced to the system is neutralized. Failure ... base 10) of the acid dissociation constant of carbonic acid. It is equal to 6.1. [HCO− 3] is the concentration of bicarbonate ...
*  1,1,3,3-Tetramethylguanidine
Rodima, Toomas; Leito, I. (2002). "Acid-Base Equilibria in Nonpolar Media. 2. Self-Consistent Basicity Scale in THF Solution ... TMG is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive bases DBU ... Tetramethylguanidine is an organic compound with the formula HNC(N(CH3)2)2. This colourless liquid is a strong base with a ... Kaupmees, K.; Trummal, A.; Leito, I. (2014). "Basicities of Strong Bases in Water: A Computational Study". Croat. Chem. Acta. ...
*  Winters' formula
Albert MS, Dell RB, Winters RW (February 1967). "Quantitative displacement of acid-base equilibrium in metabolic acidosis". ... "Case 1: Acid Base Tutorial, University of Connecticut Health Center". Retrieved 2009-05-09. "Acid-Base Disorders: Acid-Base ... R.W. Winters, is a formula used to evaluate respiratory compensation when analyzing acid-base disorders and a metabolic ...
*  Determination of equilibrium constants
This is suitable for all acid-base equilibria. log10 β values between about 2 and 11 can be measured directly by potentiometric ... Equilibrium constants are determined in order to quantify chemical equilibria. When an equilibrium constant K is expressed as a ... When the electrode is calibrated with solutions of known concentration, by means of a strong acid-strong base titration, for ... The equilibrium expression above is a function of the concentrations [A], [B] etc. of the chemical species in equilibrium. The ...
*  Thomas Dale Stewart
Later he worked on acid-base equilibria of organic nitrogen compounds, as well as reaction kinetics. Thomas Dale Stewart, ...
*  Sarafotoxin
The same study also found marked disturbances in gas exchange and acid-base equilibrium after injection with the toxin. Acute ... SRTXs complete cDNA sequence comprises 1948 base pairs (bp) coding for a pre-pro-polypeptide of 543 amino acids which starts ... The amino acid sequence comprises one sequence of 39 amino acidic residues followed by 11 sequences of 40 residues, each of it ... Each contains twenty-one amino acid residues that spontaneously fold into a defined tertiary structure with two interchain- ...
*  Paroxysmal nocturnal hemoglobinuria
... study of the mechanism of haemolysis in relation to acid-base equilibrium". N Engl J Med. 217 (23): 915-918. doi:10.1056/ ... Based on the levels of these cell proteins, erythrocytes may be classified as type I, II, or III PNH cells. Type I cells have ... If this was positive, the Ham's acid hemolysis test (after Dr Thomas Ham, who described the test in 1937) was performed for ... The Ham test involves placing red blood cells in mild acid; a positive result (increased RBC fragility) indicates PNH or ...
*  Mexazolam
Kurono, Y; Kamiya, K; Kuwayama, T; Jinno, Y; Yashiro, T; Ikeda, K (1987). "Kinetics and mechanism of the acid-base equilibrium ... HMG-CoA reductase inhibitors including simvastatin, simvastatin acid, lovastatin, fluvastatin, atorvastatin and cerivastatin ...
*  Acid
Some organisms produce acids for defense; for example, ants produce formic acid. Acid-base equilibrium plays a critical role in ... Fluoroacetic acid Trifluoroacetic acid Chloroacetic acid Dichloroacetic acid Trichloroacetic acid Normal carboxylic acids are ... Examples of strong acids are hydrochloric acid (HCl), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HClO4), ... Examples in organic acids include formic acid (HCOOH), acetic acid (CH3COOH) and benzoic acid (C6H5COOH). Polyprotic acids, ...
*  Ion speciation
Most of them can handle much more complicated equilibria than acid-base equilibria in solution. For details concerning general ... Any acid with a pKa less than about −2 is said to be a strong acid. Strong acids are said to be fully dissociated. There is no ... A weak acid may be defined as an acid with pKa greater than about −2. An acid with pKa = −2 would be 99% dissociated at pH 0, ... Outside the transition range the concentration of acid or conjugate base is less than 10% and the colour of the major species ...
*  Hydronium
"Confusing Quantitative Descriptions of Brønsted-Lowry Acid-Base Equilibria in Chemistry Textbooks - A Critical Review and ... Acids whose ionization constant is below 109 generally cannot form stable H 3O+ salts. For example, hydrochloric acid has an ... However, perchloric acid has an ionization constant of 1010, and if liquid anhydrous perchloric acid and water are combined in ... It is the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a ...
*  Red king crab
... acid base equilibrium. The red king crab has five sets of gills that are used for respiration which are located in the ... The carapace is a covering that consists of sheets of exoskeleton that overhang the thorax vertically to fit over the base of ... an opening in the carapace near the base of the chelipeds, dorsally over the gills, and anteriorly to exit beside the head. Due ...
*  Equilibrium chemistry
Acid-base equilibria are important in a very wide range of applications, such as acid-base homeostasis, ocean acidification, ... Brønsted and Lowry characterized an acid-base equilibrium as involving a proton exchange reaction: acid + base ⇌ {\displaystyle ... For aqueous solutions of an acid HA, the base is water; the conjugate base is A− and the conjugate acid is the solvated ... conjugate acid. An acid is a proton donor; the proton is transferred to the base, a proton acceptor, creating a conjugate acid ...
*  List of MeSH codes (G09)
File "2006 MeSH Trees".) MeSH G09.188.250.051 --- acid-base equilibrium MeSH G09.188.250.106 --- bleeding time MeSH G09.188. ...
*  Resonant inelastic X-ray scattering
"Identification of valence electronic states of aqueous acetic acid in acid-base equilibrium using site-selective X-ray emission ... 4] P. Marra, J. van den Brink, S. Sykora, Theoretical approach to resonant inelastic X-ray scattering in iron-based ... Intracellular metal speciation, high-temperature superconductors, e.g., cuprates., iron-based superconductors, Semiconductors, ... aqueous acetic acid, aqueous glycine high pressure. X-ray Raman scattering W. Schuelke, Electron Dynamics by Inelastic X-Ray ...
*  List of MeSH codes (G07)
... acid-base equilibrium MeSH G07.621.265 --- body temperature regulation MeSH G07.621.265.500 --- thermogenesis MeSH G07.621.487 ...
*  Stability constants of complexes
Bjerrum recognised that the formation of a metal complex with a ligand was a kind of acid-base equilibrium: there is ... For more details see: acid-base reaction, acid catalysis, acid-base extraction. The thermodynamics of metal ion complex ... Alpha hydroxy acids and other hydroxycarboxylic acids crown ethers phosphonic acids imidazoles and histamines amino acids with ... Hard acids form stronger complexes with hard bases than with soft bases. In general terms hard-hard interactions are ...
*  Charlot equation
... that the formal concentration is the same as the equilibrium concentration). For an acid-base equilibrium such as AH ⇌ A− + H+ ... the sum of the equilibrium concentrations of the acid and its conjugate base has to remain equal to the sum of their analytical ... Ka is the acid dissociation constant, Ca and Cb are the analytical concentrations of the acid and its conjugate base, ... The equilibrium concentration [M+] is constant and equal to the analytical concentration of the base, Cb. Therefore, [ A − ] = ...
*  Predominance diagram
... and pH where a chemical species has the highest concentration in solutions in which there are multiple acid-base equilibria. ... There are two independent equilibria, with equilibrium constants defined as follows. A third equilibrium constant can be ... "Equilibria of chromate(VI) species in acid medium and ab initio studies of these species". Polyhedron. 16 (21): 3835-3846. doi: ... Another complication is that many of the higher polymers are formed extremely slowly, such that equilibrium may not be attained ...
*  Solvent effects
The ionization equilibrium of an acid or a base is affected by a solvent change. The effect of the solvent is not only because ... Consider the following acid dissociation equilibrium: HA ⇌ A− + H+, Water, being the most polar-solvent listed above, ... of its dielectric constant and its ability to preferentially solvate and thus stabilize certain species in acid-base equilibria ... Protic solvents react with strong nucleophiles with good basic character in an acid/base fashion, thus decreasing or removing ...
*  Chemical equilibrium
Chromatography Solubility product Uptake and release of oxygen by haemoglobin in blood Acid-base equilibria: acid dissociation ... though the equilibrium constant will stay the same). If mineral acid is added to the acetic acid mixture, increasing the ... For instance, in the case of a dibasic acid, H2A dissolved in water the two reactants can be specified as the conjugate base, ... Applying the general formula for an equilibrium constant to the specific case of a dilute solution of acetic acid in water one ...
*  Micellar liquid chromatography
... and could be used for any secondary chemical equilibria such as acid-base equilibria, and ion-pairing, Foley further refined ... These models allow for further enhancement of the optimization of the separation of weak acids and bases. One research group, ... by Arunyanart and Cline-Love and Rodgers and Khaledi describe the effect of pH on the retention of weak acids and bases. These ... It is based and depends on a given calibration series determined experimentally. The lipophilicity index should be independent ...
*  Tomatine
... because of participation in acid-base equilibriums. Tomatine can also stimulate the immune system by participation in a ... It is likely that hydrolysis of tomatine takes place, but it is not known if it is acid or glycosidase catalyzed. In vitro ... plus high acid content. Consequently, tomatoes were generally not eaten in Britain until the mid-18th century. In 1837, the ... "Systems-based Discovery of Tomatidine as a Natural Small Molecule Inhibitor of Skeletal Muscle Atrophy". Journal of Biological ...
*  Isoelectric point
... a suite of spreadsheets for computing acid-base equilibria (charge versus pH plot of amphoteric molecules e.g., amino acids) ... "Calculation of the isoelectric point of tryptic peptides in the pH 3.5-4.5 range based on adjacent amino acid effects". ... For an amino acid with only one amine and one carboxyl group, the pI can be calculated from the mean of the pKas of this ... Amino acids that make up proteins may be positive, negative, neutral, or polar in nature, and together give a protein its ...
*  Halobacterium salinarum
Amino acids are the main source of chemical energy for H. salinarum, particularly arginine and aspartate, though they are able ... NRC-1 genome consists of 2,571,010 base pairs on one large chromosome and two mini-chromosomes. The genome encodes 2,360 ... Potassium levels are not at equilibrium with the environment, so H. salinarum expresses multiple active transporters which pump ... Vreeland, H; Rosenzweig, W D; Lowenstein, T; Satterfield, C; Ventosa, A (December 2006). "Fatty acid and DNA analyses of ...
*  PH
ISBN 978-0-470-38123-6. The pH Scale Chem1 Virtual Textbook, Acid-base Equilibria and Calculations Red Cabbage pH Indicator ... A weak acid or the conjugate acid of a weak base can be treated using the same formalism. Acid: HA ↽ − − ⇀ H + + A − {\ ... and organs is usually tightly regulated in a process called acid-base homeostasis. The most common disorder in acid-base ... When an acid is dissolved in water, the pH will be less than 7 (25 °C). When a base, or alkali, is dissolved in water, the pH ...
Isoflurane-induced acidosis depresses basal and PGE(2)-stimulated duodenal bicarbonate secretion in mice  Isoflurane-induced acidosis depresses basal and PGE(2)-stimulated duodenal bicarbonate secretion in mice
Acid-Base Equilibrium/drug effects, Acidosis/blood/chemically induced/*metabolism, Animals, Bicarbonates/*metabolism, Blood ... When running in vivo experiments, it is imperative to keep arterial blood pressure and acid-base parameters within the normal ... arterial acid-base balance, and duodenal mucosal bicarbonate secretion (DMBS) were studied. Two intra-arterial fluid support ... it is recommended to supplement with a Na2CO3 infusion to maintain a normal acid-base balance. ...
more infohttp://uu.diva-portal.org/smash/record.jsf?pid=diva2:39017
Acid-base equilibria menu  Acid-base equilibria menu
Theories of acids and bases . . .. Describes the Arrhenius, Bronsted-Lowry, and Lewis theories of acids and bases, and explains ... acid-base indicators . . .. Explains how simple indicators work, and what determines the choice of indicator for a particular ... Describes the way that pH changes during various acid-base titrations.. ... Includes the meaning of the term conjugate as applied to acid-base pairs. ...
more infohttp://chemguide.co.uk/physical/acideqiamenu.html
3.04 Finding pH - Acid-Base Equilibria | Coursera  3.04 Finding pH - Acid-Base Equilibria | Coursera
The concept of equilibrium is applied to acid and base solutions. To begin, the idea of weak acids and bases is explored along ... Acid-Base Equilibria. The concept of equilibrium is applied to acid and base solutions. To begin, the idea of weak acids and ... for both strong and weak acids and bases. Aqueous salt solutions are classified as acids and bases and the multi-step ... However because the week acid process is in equilibrium process. and we've got our equilibrium arrow there. It is an ...
more infohttps://www.coursera.org/learn/advanced-chemistry/lecture/2uBfc/3-04-finding-ph
3.07 Types of Acids - Acid-Base Equilibria | Coursera  3.07 Types of Acids - Acid-Base Equilibria | Coursera
The concept of equilibrium is applied to acid and base solutions. To begin, the idea of weak acids and bases is explored along ... Acid-Base Equilibria. The concept of equilibrium is applied to acid and base solutions. To begin, the idea of weak acids and ... Making it a Louis acid. Now we completed our unit on acid-base equilibria. There are other issues surrounding this which we ... So much in the same way that we talked about conjugate acids and bases with Bronsted-Lowry acids and bases, we see a similar ...
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Acid Base Equilibrium | Physics Forums - The Fusion of Science and Community  Acid Base Equilibrium | Physics Forums - The Fusion of Science and Community
Help - Confusion acid-base equilibrium in water Jan 24, 2014. Acid-base equilibrium question titration Jun 18, 2011. ... Titration of amino acid with strong base Sep 5, 2015. ... Similar Threads - Acid Base Equilibrium. Date. Question on Ksp ... Why equilibrium favours weak acid or weak base Oct 10, 2015. ...
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ABEW - Acid base equilibrium for Windows screenshot. free demo.  ABEW - Acid base equilibrium for Windows screenshot. free demo.
Acid base equilibrium for Windows 1.7 , Screenshot. ABEW - Acid base equilibrium for Windows 1.7. Similar software:. ... Acid base equilibrium for Windows 1.7. Home , Software , Education , Teaching Tools , ABEW - Acid base equilibrium for Windows ... Built-in database of common weak acids and bases.*CurTiPot Acid-Base pH and Titration 3.5.4 All-in-one freeware for pH and ... Find all software similar on ABEW - Acid base equilibrium for Windows 1.7. ...
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Acid-base equilibria | Physics Forums - The Fusion of Science and Community  Acid-base equilibria | Physics Forums - The Fusion of Science and Community
Acetic acid is not a strong acid and acetate can act as a base under certain conditions. Hydrochloric acid is a strong acid and ... the conjugate base is going to react with water based on the relation of the base equilibrium constant to the acid equilibrium ... So, which acid/base reaction you use depends on the exact identity of the acid you're examining. For something like acetic acid ... The reason you have two equilibria expressions is because when you deprotonate an acid, you get a proton and the conjugate base ...
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Baylor, Scott / Chapter 16 Acid-Base Equilibria & Solubility Equilibria  Baylor, Scott / Chapter 16 Acid-Base Equilibria & Solubility Equilibria
Chapter 16 Acid-Base Equilibria & Solubility Equilibria * CHAPTER 16 TEST ANNOUNCEMENT!!!!! * Quick Chapter 16 notes ...
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Acid-Base Equilibrium During Cyclopropane Anesthesia and Operation in Infants | Anesthesiology | ASA Publications  Acid-Base Equilibrium During Cyclopropane Anesthesia and Operation in Infants | Anesthesiology | ASA Publications
Acid-Base Equilibrium During Cyclopropane Anesthesia and Operation in Infants You will receive an email whenever this article ... Acid-Base Equilibrium During Cyclopropane Anesthesia and Operation in Infants. Anesthesiology 3 1966, Vol.27, 127-131. doi: ... Robert N. Reynolds; Acid-Base Equilibrium During Cyclopropane Anesthesia and Operation in Infants. Anesthesiology 1966;27(2): ...
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Acid-Base Equilibria Acid-Base Definitions - PDF  Acid-Base Equilibria Acid-Base Definitions - PDF
AcidBse Equiliri Acids shrp, sour tste; Bses sopy, itter tste Neutrliztion (proton trnsfer) rections cid se slt wter (or other ... Acid and Bases. What is an Acid? Acids & Bases. Acids & Bases hpter 1 Acids & Bses Acid nd Bses Acid nd Bses Acid nd Bses Wht ... BRØNSTED ACIDS & BASES ACIDS & BASES BRØNSTED ACIDS & BASES BRØNSTED ACIDS & BASES Brønsted acids are proton donors. Brønsted ... A. Acids. B. Bases Chem 1B Dr. White 1 Chapter 14 Acids and Bases 14.1 Nature of Acids and Bases A. Acids B. Bases Chem 1B Dr. ...
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Exp10 - Application of Acid/Base Equilibria Buffers and Titrations Excel Template 1 2 3 4 5 6 7 8 9 10 A B C Chem1310 Name...  Exp10 - Application of Acid/Base Equilibria Buffers and Titrations Excel Template 1 2 3 4 5 6 7 8 9 10 A B C Chem1310 Name...
Application of Acid/Base Equilibria - Buffers and Titrations Excel Template 1 2 3 4 5 6 7 8 9 10 A B C Chem1310 Name: Partner's ... 11/6/2008 Applications of Acid/Base Equilibria - Buffers and Titrations A. Buffers B. Acid/Base Analysis - Standardization- ... H C H O O C 3 Strength of Vinegar by Acid-Base Titration Acid-Base 100 points The goa ... Exp10 - Application of Acid/Base Equilibria Buffers and.... This preview shows document pages 1 - 2. Sign up to view the full ...
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Acid / Base Equilibria  Acid / Base Equilibria
... is the conjugate base of the acid acetic acid, HC2H3O2. Since HC2H3O2 is a weak acid, its conjugate base has enough strength to ... Acid / Base Equilibria. This document explains how the concepts of chemical equilibrium can be applied to the ionization of ... or base) will have ionized at equilibrium, so the actual concentration of molecular acid (or base) may not be that which is ... where the molecular acid or base is) and the less ionization there is. It also works better when the acid or base is more ...
more infohttp://www.dlrgenchem.com/LECTURES/AcidBaseEquilibria.htm
Acid / Base Equilibria  Acid / Base Equilibria
... is the conjugate base of the acid acetic acid, HC2H3O2. Since HC2H3O2 is a weak acid, its conjugate base has enough strength to ... Acid / Base Equilibria. This document explains how the concepts of chemical equilibrium can be applied to the ionization of ... or base) will have ionized at equilibrium, so the actual concentration of molecular acid (or base) may not be that which is ... where the molecular acid or base is) and the less ionization there is. It also works better when the acid or base is more ...
more infohttp://dlrgenchem.com/LECTURES/AcidBaseEquilibria.htm
Acid-base Equilibria | Pre-U Certificate in Chemistry 9791 by tia xn | Teaching Resources  Acid-base Equilibria | Pre-U Certificate in Chemistry 9791 by tia xn | Teaching Resources
Acid-base Equilibria , Pre-U Certificate in Chemistry 9791. (no rating)0. customer reviews ... These are my comprehensive notes for CIE Pre U Chemistry on the topic of acid-base equilibria, with my own illustrations using ...
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3.06a Acid-base properties of aqueous salts, part 1 - Acid-Base Equilibria | Coursera  3.06a Acid-base properties of aqueous salts, part 1 - Acid-Base Equilibria | Coursera
To begin, the idea of weak acids and bases is explored along with the equilibrium constants associated ... ... The concept of equilibrium is applied to acid and base solutions. ... Acid-Base Equilibria. The concept of equilibrium is applied to acid and base solutions. To begin, the idea of weak acids and ... for both strong and weak acids and bases. Aqueous salt solutions are classified as acids and bases and the multi-step ...
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Chemistry PowerPoint: Acids and Bases and Aqueous Equilibria | TpT  Chemistry PowerPoint: Acids and Bases and Aqueous Equilibria | TpT
General properties of acids and bases - Common acids and bases - Uses of common acids and bases - Arrhenius, Bronsted-Lowry, ... Common acids and bases - Uses of common acids and bases - Arrhenius, Bronsted-Lowry, and Lewis acid and base definitions, ... and Lewis acid and base definitions, examples, and reactions of each - Conjugate acid-base pairs - How water ... examples, and reactions of each - Conjugate acid-base pairs - How water ...
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AP Chemistry PowerPoint: Acids and Bases and Aqueous Equilibria | TpT  AP Chemistry PowerPoint: Acids and Bases and Aqueous Equilibria | TpT
General properties of acids and bases - Common acids and bases - Uses of common acids and bases - Arrhenius, Bronsted-Lowry, ... Common acids and bases - Uses of common acids and bases - Arrhenius, Bronsted-Lowry, and Lewis acid and base definitions, ... and Lewis acid and base definitions, examples, and reactions of each - Conjugate acid-base pairs - How water ... examples, and reactions of each - Conjugate acid-base pairs - How water ...
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Chemistry: The Science in Context (4th Edition) Chapter 16 - Acid-Base and Solubility Equilibria: Reactions in Soil and Water -...  Chemistry: The Science in Context (4th Edition) Chapter 16 - Acid-Base and Solubility Equilibria: Reactions in Soil and Water -...
Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems - Page 838 51 including work step by step written ... Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems * Acid-Base and Solubility Equilibria: Reactions in ... Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems * Acid-Base and Solubility Equilibria: Reactions in ... Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems * Acid-Base and Solubility Equilibria: Reactions in ...
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Chemistry: The Science in Context (4th Edition) Chapter 16 - Acid-Base and Solubility Equilibria: Reactions in Soil and Water -...  Chemistry: The Science in Context (4th Edition) Chapter 16 - Acid-Base and Solubility Equilibria: Reactions in Soil and Water -...
Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems - Page 838 45 including work step by step written ... Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems * Acid-Base and Solubility Equilibria: Reactions in ... Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems * Acid-Base and Solubility Equilibria: Reactions in ... Acid-Base and Solubility Equilibria: Reactions in Soil and Water - Problems * Acid-Base and Solubility Equilibria: Reactions in ...
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Advanced Weak Acid and Weak Base Equilibria Problems  Advanced Weak Acid and Weak Base Equilibria Problems
V. Advanced Weak Acid and Weak Base Equilibria. V-1. Introduction to Acidic. and Basic Salts. V-2. Sample Problem. V-3. List of ... Equilibrium Practice Problems. CHP Home. Table of Contents. Jump to the top of this page.. Copyright © 1997-2000 by Brian M. ... The following problems are straight-forward equilibria problems. When you are done with each problem close the window to return ...
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Equilibrium partitioning of naphthenic acids and bases and their consequences on interfacial properties  Equilibrium partitioning of naphthenic acids and bases and their consequences on interfacial properties
The model was tested on 2 acids and 2 bases. After a review of the properties of crude oil acids and bases, the equilibrium ... two bases, two acids and all four components over a pH interval to identify any interfacial acid-base interactions. No ... Equilibrium partitioning of naphthenic acids and bases and their consequences on interfacial properties. Bertheussen, Are; ... The partitioning of the two acids and the low molecular weight base was successfully modelled by considering the acid ...
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9780077468446 - Package: Chemistry - The Molecular | eCampus.com  9780077468446 - Package: Chemistry - The Molecular | eCampus.com
17 Equilibrium: The Extent of Chemical Reactions. 18 Acid-Base Equilibria 19 Ionic Equilibria in Aqueous Systems. 20 ... Appendix C Equilibrium Constants at 298 K Appendix D Standard Electrode (Half-Cell) Potentials at 298 K. ...
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Synonyms and Antonyms for glutaminic-acid | Synonym.com  Synonyms and Antonyms for glutaminic-acid | Synonym.com
3. acid-base equilibrium (n.). (physiology) the normal equilibrium between acids and alkalis in the body ... 2. acid-base indicator (n.). an indicator that changes color on going from acidic to basic solutions ... 1. glutaminic acid (n.). an amino acid occurring in proteins; important in the nitrogen metabolism of plants; used in ... 6. acid (n.). any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a ...
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Synonyms and Antonyms for homogentisic-acid | Synonym.com  Synonyms and Antonyms for homogentisic-acid | Synonym.com
3. acid-base equilibrium (n.). (physiology) the normal equilibrium between acids and alkalis in the body ... 2. acid-base indicator (n.). an indicator that changes color on going from acidic to basic solutions ... 1. homogentisic acid (n.). an acid formed as an intermediate product of the metabolism of tyrosine and phenylalanine ... 6. acid (n.). any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a ...
more infohttp://www.synonym.com/synonyms/homogentisic-acid
  • Each contains twenty-one amino acid residues that spontaneously fold into a defined tertiary structure with two interchain-cysteine linkages (disulfide bonds) and a long hydrophobic tail. (wikipedia.org)
  • The amino acid sequence comprises one sequence of 39 amino acidic residues followed by 11 sequences of 40 residues, each of it contains one SRTX sequence preceded by 19 spacer amino acids. (wikipedia.org)
  • For an amino acid with only one amine and one carboxyl group, the pI can be calculated from the mean of the pKas of this molecule. (wikipedia.org)
  • An acid is a molecule or ion capable of donating a hydron (proton or hydrogen ion H+), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid). (wikipedia.org)
  • The first category of acids is the proton donors or Brønsted acids. (wikipedia.org)
  • The acidity of hydronium is the implicit standard used to judge the strength of an acid in water: strong acids must be better proton donors than hydronium, otherwise a significant portion of acid will exist in a non-ionized state (i.e.: a weak acid). (wikipedia.org)
  • As you progress through the unit, think about these focusing questions: What is happening in a system at equilibrium? (docplayer.net)
  • Some improvements in the methodology (especially in the determination of the pK values for modified amino acids) have been also proposed. (wikipedia.org)
  • We have to figure out what fraction for acid dissociate into the ions. (coursera.org)
  • The molecules in pure water auto-dissociate (i.e.: react with each other) into hydronium and hydroxide ions in the following equilibrium: 2 H 2O ⇌ OH− + H 3O+ In pure water, there is an equal number of hydroxide and hydronium ions, so it is a neutral solution. (wikipedia.org)
  • Finally, the concept of Lewis acids and bases is discussed and demonstrated through examples. (coursera.org)
  • The second category of acids are Lewis acids, which form a covalent bond with an electron pair. (wikipedia.org)
  • However, hydrogen chloride, acetic acid, and most other Brønsted-Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. (wikipedia.org)
  • In modern terminology, an acid is implicitly a Brønsted acid and not a Lewis acid, since chemists almost always refer to a Lewis acid explicitly as a Lewis acid. (wikipedia.org)
  • Interestingly, although alcohols and amines can be Brønsted-Lowry acids, they can also function as Lewis bases due to the lone pairs of electrons on their oxygen and nitrogen atoms. (wikipedia.org)