| AAN | AIDS-associated nephropathy; alpha-amino nitrogen; American Academy of Neurology; American Academy o... |
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| EAA | electroacupuncture analgesia; Epilepsy Association of America; essential amino acid; excitatory amin... |
| AAD | acute agitated delirium; alloxazine adenine dinucleotide; alpha-1-antitrypsin deficiency; American A... |
| ar | aromatic |
| arom | aromatic |
para-amino salicylic acid
| aromatic series | All the compounds derived from benzene, or similar cyclic compounds that obey Huckel's rule, distinguished from those compounds that are acyclic or that contain rings that lack the conjugated double bond structure characteristic of benzene. (05 Mar 2000) |
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| aromatic water | 1. To wet or supply with water; to moisten; to overflow with water; to irrigate; as, to water land; to water flowers. "With tears watering the ground." (Milton) "Men whose lives gilded on like rivers that water the woodlands." (Longfellow) 2. To supply with water for drink; to cause or allow to drink; as, to water cattle and horses. 3. To wet and calender, as cloth, so as to impart to it a lustrous appearance in wavy lines; to diversify with wavelike lines; as, to water silk. Cf. Water. 4. To add water to (anything), thereby extending the quantity or bulk while reducing the strength or quality; to extend; to dilute; to weaken. To water stock, to increase the capital stock of a company by issuing new stock, thus diminishing the value of the individual shares. Cf. Water. Origin: AS. Waeterian, gewaeterian. 1. The fluid which descends from the clouds in rain, and which forms rivers, lakes, seas, etc. "We will drink water." ."Powers of fire, air, water, and earth." . Pure water consists of hydrogen and oxygen, H2O, and is a colourless, odorless, tasteless, transparent liquid, which is very slightly compressible. at its maximum density, 39 deg Fahr. Or 4 deg C, it is the standard for specific gravities, one cubic centimeter weighing one gram. It freezes at 32 deg Fahr. Or 0 deg C. And boils at 212 deg Fahr. Or 100 deg C. (see Ice, Steam). It is the most important natural solvent, and is frequently impregnated with foreign matter which is mostly removed by distillation; hence, rain water is nearly pure. It is an important ingredient in the tissue of animals and plants, the human body containing about two thirds its weight of water. 2. A body of water, standing or flowing; a lake, river, or other collection of water. "Remembering he had passed over a small water a poor scholar when first coming to the university, he kneeled." (Fuller) 3. Any liquid secretion, humor, or the like, resembling water; especially, the urine. 4. <pharmacology> A solution in water of a gaseous or readily volatile substance; as, ammonia water. 5. The limpidity and luster of a precious stone, especially a diamond; as, a diamond of the first water, that is, perfectly pure and transparent. Hence, of the first water, that is, of the first excellence. 6. A wavy, lustrous pattern or decoration such as is imparted to linen, silk, metals, etc. See Water, 3, Damask, and Damaskeen. 7. An addition to the shares representing the capital of a stock company so that the aggregate par value of the shares is increased while their value for investment is diminished, or "diluted." Water is often used adjectively and in the formation of many self-explaining compounds; as, water drainage; water gauge, or water-gauge; waterfowl, water-fowl, or water fowl; water-beaten; water-borne, water-circled, water-girdled, water-rocked, etc. Hard water. See Hard. Inch of water, a unit of measure of quantity of water, being the quantity which will flow through an orifice one inch square, or a circular orifice one inch in diameter, in a vertical surface, under a stated constant head; also called miner's inch, and water inch. The shape of the orifice and the head vary in different localities. In the Western United States, for hydraulic mining, the standard aperture is square and the head from 4 to 9 inches above its center. In Europe, for experimental hydraulics, the orifice is usually round and the head from 1/12 of an inch to 1 inch above its top. Mineral water, waters which are so impregnated with foreign ingredients, such as gaseous, sulphureous, and saline substances, as to give them medicinal properties, or a particular flavor or temperature. Soft water, water not impregnated with lime or mineral salts. To hold water. See Hold, To keep one's head above water, to keep afloat; fig, to avoid failure or sinking in the struggles of life. To make water. To pass urine. <medicine> Hydrothorax. Other phrases, in which water occurs as the first element, will be found in alphabetical order in the Vocabulary. Origin: AS. Waeter; akin to OS. Watar, OFries. Wetir, weter, LG. & D. Water, G. Wasser, OHG. Wazzar, Icel. Vatn, Sw. Vatten, Dan. Vand, Goth. Wat, O. Slav. & Russ. Voda, Gr, Skr. Udan water, ud to wet, and perhaps to L. Unda wave. Cf. Dropsy, Hydra, Otter, Wet, Whisky. Source: Websters Dictionary (01 Mar 1998) |
| polycyclic hydrocarbons, aromatic | <chemical> A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odour characteristic of most substances of this nature. Pharmacological action: carcinogens. (12 Dec 1998) |
| hydrocarbons, aromatic | Organic compounds composed exclusively of carbon and hydrogen. They are unsaturated hexagonal ring structures with a closed conjugated system of double bonds that gives them the characteristic chemical properties of the parent aromatic hydrocarbon, benzene. (12 Dec 1998) |
| acidic amino acid | An Amino acid with a second acid moiety, e.g., glutamic acid, aspartic acid, cysteic acid. (05 Mar 2000) |
| activated amino acid | The product formed by the condensation of the acyl radical of an amino acid and adenosine 5'-monophosphate (originally in the form of adenosine 5'-triphosphate, with elimination of a pyrophosphoric group). Formed in the first step of protein biosynthesis. Synonym: activated amino acid. (05 Mar 2000) |
| alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid | <chemical> Alpha-amino-2,3-dihydro-5-methyl-3-oxo-4-isoxazolepropanoic acid. An ibotenic acid homolog and glutamate agonist. The compound is the defining agonist for the ampa subtype of glutamate receptors (receptors, ampa). It has been used as a radionuclide imaging agent but is more commonly used as an experimental tool in cell biological studies. Pharmacological action: excitatory amino acid agonists. Chemical name: 4-Isoxazolepropanoic acid, alpha-amino-2,3-dihydro-5-methyl-3-oxo- (12 Dec 1998) |
| alpha-amino acid | Typically, an amino acid of the general formula R-CHNH2-COOH (i.e., the NH2 in the a position); the l forms of these are the hydrolysis products of proteins. In rarer usages, this class of molecules also includes alpha-amino phosphoric acids and alpha-aminosulfonic acids. (05 Mar 2000) |
| alpha-amino acid esterase | <enzyme> Converts alpha-amino acid esters and water to alpha-amino acids and alcohol Registry number: EC 3.1.1.43 Synonym: alpha-amino acid ester hydrolase (26 Jun 1999) |
| alpha-amino-beta-ketoadipic acid | 2-Amino-3-oxo-1,6-hexanedioic acid;an intermediate of porphobilinogen synthesis formed by d-aminolevulinic acid synthase from succinyl-CoA and glycine; it rapidly decarboxylates to d-aminolevulinic acid. (05 Mar 2000) |
| amino- | <prefix> Prefix denoting a compound containing the radical, -NH2. Origin: an(monia) + in(e) + -o- (05 Mar 2000) |
| amino acid | <biochemistry> A class of organic molecules that containing an amino group and can combine in linear arrays to form proteins in living organisms. There are twenty common amino acids: alanine, arginine, aspargine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. They are key components in all living things from which proteins are synthesised by formation of peptide bonds during ribosomal translation of messenger RNA. All the amino acids have the L configuration, except glycine which is not optically active. Other amino acids occurring in proteins, such as hydroxyproline in collagen, are formed by post translational enzymatic modification of amino acid residues in polypeptide chains. There are also several important amino acids, such as the neurotransmitter y aminobutyric acid, that have no relation to proteins. Amino acids can now be produced by biotechnology in bulk using fermentation and biotransformation. Acronym: AA (13 Nov 1997) |
| amino acid activating enzyme | <enzyme> Enzymes catalyzing the formation of a specific aminoacyl-tRNA from an amino acid and adenosine 5'-triphosphate with the concomitant formation of adenosine 5'-monophosphate and pyrophosphate. Synonym: amino acid activating enzyme, aminoacyl-tRNA ligases. (05 Mar 2000) |
| amino acid activation | The first step of protein synthesis, whereby an amino acid reacts with adenosine triphosphate in the presence of aminoacyl RNA synthetase to produce an amino acid adenylate, which provides the energy necessary for the attachment of the amino acid to a specific transfer RNA molecule. (12 Dec 1998) |
| amino acid analysis | Determination and identification of amino acid content of a macromolecule, identification of a specific amino acid in macromolecules, often a mutated protein, identification and quantitation of amino acid content in blood plasma or urine; a key diagnostic aid. (05 Mar 2000) |