| base | <chemistry> The nonacid part of a salt, a substance that combines with acids to form salts, a substance that dissociates to give hydroxide ions in aqueous solutions, a substance whose molecule or ion can combine with a proton (hydrogen ion), a substance capable of donating a pair of electrons (to an acid) for the formation of a coordinate covalent bond. (13 Nov 1997) |
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| base analogue | <biochemistry> A chemical which resembles a nucleotide base. They can substitute the Purine and pyrimidine bases that normally appear in DNA, despite minor differences in structure. May be used for inducing mutations, including point mutations. For example: 5 bromouracil can replace thymine or 2 aminopurine replace adenine. (13 Nov 1997) |
| base composition | <biochemistry> In reference to nucleic acid, the proportion of the total bases consisting of guanine plus cytosine or thymine plus adenine base pairs. Usually expressed as a guanine + cytosine (G+C) value, for example 60% G+C. (09 Oct 1997) |
| base deficit | A decrease in the total concentration of blood buffer base, indicative of metabolic acidosis or compensated respiratory alkalosis. (05 Mar 2000) |
| base dissociation constant | <chemistry> This is the equilibrium constant for the reaction in which a weak base breaks apart in water to form its conjugate acid and hydroxide ion. (09 Oct 1997) |
| base excess | A measure of metabolic alkalosis, usually predicted from the Siggaard-Andersen nomogram; the amount of strong acid that would have to be added per unit volume of whole blood to titrate it to pH 7.4 while at 37캜 and at a carbon dioxide pressure of 40 mm Hg. (05 Mar 2000) |
| base hospital | A hospital unit located in a military or recreational encampment; usually of small size and limited facilities, for immediate care of illnesses and injuries. Synonym: camp hospital. (05 Mar 2000) |
| base in DNA | A unit of the DNA. There are 4 bases: adenine (A), guanine (G), thymine (T), and cytosine (C). The sequence of bases (for example, CAG) is the genetic code. (12 Dec 1998) |
| base material | Any substance from which a denture base may be made, such as shellac, acrylic resin, vulcanite, polystyrene, metal, etc. (05 Mar 2000) |
| base metal | A metal that is readily oxidised; e.g., iron, copper. (05 Mar 2000) |
| base microscopical | <microscopy> The microscope's supporting structure such as the horseshoe type. Heavier bases, some containing the entire illuminating system, began to appear after World War II. (05 Aug 1998) |
| base of arytenoid cartilage | The part of the arytenoid cartilage that articulates with the cricoid cartilage and from which the muscular process extends laterally and the vocal process projects anteriorly. Synonym: basis cartilaginis arytenoideae. (05 Mar 2000) |
| base of bladder | The fundus is formed by the posterior wall which is somewhat convex. Synonym: fundus vesicae urinariae, bas-fond, base of bladder. (05 Mar 2000) |
| base of brain | The inferior surface of the brain visible when seen from below. Synonym: facies inferior cerebri, basis cerebri, inferior cerebral surface. (05 Mar 2000) |
| base of cochlea | The enlarged part of the cochlea that is directed posteriorly and medially and lies close to the internal acoustic meatus. Synonym: basis cochleae. (05 Mar 2000) |
| acid-base balance | The normal balance between acid and base in the blood plasma, expressed in the hydrogen ion concentration or pH, resulting from the relative amounts of acidic and basic materials ingested and produced by body metabolism, compared to the relative amounts of acidic and basic materials excreted from the body and consumed by body metabolism; the normal state of acid-base balance is not one of neutrality, with equal concentrations of hydrogen and hydroxyl ions, but a more alkaline state with a certain excess of hydroxyl ions. Synonym: acid-base equilibrium. (05 Mar 2000) |
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| acid-base equilibrium | A condition in which the net rate of acid or alkali production by the body is balanced by the net rate of acid or alkali excretion from the body, resulting in a stable concentration of hydrogen ions in the body fluids. (12 Dec 1998) |
| acid-base imbalance | Disturbances in the acid-base equilibrium of the body. (12 Dec 1998) |
| acrylic resin base | A form made of acrylic resin molded to conform to the tissues of the alveolar process and used to support the teeth of a prosthesis. (05 Mar 2000) |
| aldehyde base | An obsolete term for an imide. (05 Mar 2000) |
| anterior cranial base | The portion of the internal base of the skull, anterior to the sphenoidal ridges and limbus, in which the frontal lobes of the brain rest. Synonym: fossa cranii anterior, anterior cranial base. (05 Mar 2000) |
| Bandrowski's base | <chemical> Reported cause of anaphylactic reaction. Synonym: n',n'-bis(4-aminophenyl)-2,5-diamino-1,4-quinonediimine (26 Jun 1999) |
| Bronsted base | Any molecule or ion that combines with a proton; e.g., OH-, CN-, NH3; this definition replaces the older and more limited concepts of base. (05 Mar 2000) |
| vegetable base | <chemistry, pharmacology> One of a large group of nitrogenous substances found in naturally in plants. They are usually very bitter and although the plant may be poisonous, many have extracts that are pharmacologically active. Examples are atropine, caffeine, coniine, morphine, nicotine, quinine, strychnine. The term is also applied to synthetic substances which have structures similar to plant alkaloids, such as procaine. (29 Sep 1997) |
| general acid-base catalysis | A catalytic reaction that involves the tranfer of a proton to or from anon-water molecule. (09 Oct 1997) |
| record base | <cell biology> A hypothetical cell adhesion molecule possibly involved in sponge cell adhesion, existence unproven. (18 Nov 1997) |
| mass at base of tongue | <radiology> Lingual thyroid, thyroglossal duct cyst, haemangioma, other neoplasm (12 Dec 1998) |
| cavity preparation base | <dentistry> A layer of dental cement, sometimes medicated, that is placed in the deep portion of a cavity preparation to protect the pulp, reduce the bulk of a metallic restoration, or eliminate undercuts. Synonym: cavity preparation base. (05 Mar 2000) |
| Reid's base line | <anatomy, radiology> A line drawn from the inferior margin of the orbit to the auricular point at the superior border of the orifice of the external auditory meatus and extending backward to the centre of the occipital bone. It is used as the zero plane in computed tomography. (05 Mar 2000) |
| cement base | <dentistry> A layer of dental cement, sometimes medicated, that is placed in the deep portion of a cavity preparation to protect the pulp, reduce the bulk of a metallic restoration, or eliminate undercuts. Synonym: cavity preparation base. (05 Mar 2000) |