| mass-action ratio | The ratio of the product of all of the product concentrations divided by the product of all of the reactant concentrations of a particular reaction; when the reaction has been completed (i.e., t = ∞), then this ratio is equal to the equilibrium constant. (05 Mar 2000) |
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| mass action theory | That large areas of brain tissue function as a whole in learned or intelligent action. (05 Mar 2000) |
| mass action transmission | <epidemiology> Transmission of infection which occurs at a rate directly proportional to the number or density of both susceptibles and infecteds present. Some authors reserve the name mass action for transmission processes of the form b X Y/N , which we associate with STD-type transmission, and describe transmission rates of the form b X Y , as pseudo-mass action ; the two are equivalent if the population size is unchanging. (05 Dec 1998) |
| cumulative action | The condition in which repeated administration of a drug may produce effect's that are more pronounced than those produced by the first dose. Synonym: cumulative action. (05 Mar 2000) |
| salt action | Any physicochemical effect produced by hypertonic concentrations of osmotically active electrolytes. (05 Mar 2000) |
| prolonged action tablet | sustained action tablet |
| sparing action | The manner in which a nonessential nutritive component, by its presence in the diet, lowers the dietary requirement for an essential component; thus, nonessential l-cysteine spares essential l-methionine and nonessential l-tyrosine spares essential l-phenylalanine. Synonym: sparing phenomenon. (05 Mar 2000) |
| specific action | The action of a drug or a method of treatment which has a direct and especially curative effect upon a disease, e.g., the action of vitamin B12 in pernicious anaemia. (05 Mar 2000) |
| specific dynamic action | The increase of heat production caused by the ingestion of food, especially of protein. (05 Mar 2000) |
| delayed-action preparations | Dosage forms of a drug that act over a period of time. (12 Dec 1998) |
| thermogenic action | Increase of heat production of the body, as by the thyroid hormone. Synonym: thermogenic action. (05 Mar 2000) |
| law of mass action | <chemistry> This law states that the rate of a given chemical reaction is proportional to concentration of the reactants. (09 Oct 1997) |
| alveolocapillary block | The presence of material that impairs the diffusion of gases between the air in the alveolar spaces and the blood in alveolar capillaries; block can be caused by oedema, cellular infiltration, fibrosis, or tumour, and results in undersaturation of peripheral arterial blood with oxygen. (05 Mar 2000) |
| anterograde block | Conduction block of an impulse traveling anywhere in its ordinary direction, for example, from the sinoatrial node toward the ventricular myocardium. (05 Mar 2000) |
| arborization block | Intraventricular block supposedly due to widespread blockage in the Purkinje ramifications and manifested in the electrocardiogram by a pattern similar to bundle-branch block but with complexes of low amplitude. (05 Mar 2000) |