| EVTV | extravascular thermal volume |
|---|---|
| LTV | lung thermal volume |
| TC | target cell; taurocholate; temperature compensation; teratocarcinoma; tertiary cleavage; tetracyclin... |
| TCD | tapetochoroidal dystrophy; T-cell depletion; thermal conductivity detector; tissue culture dose; tra... |
| TD | tabes dorsalis; tardive dyskinesia; T-cell dependent; temporary disability; terminal device; tetanus... |
| nitrogen cycle | <biochemistry> The global cycle of moving various forms of nitrogen through the air, water, soil, plants, animals of the planet. See: nitrogen fixation. (09 Oct 1997) |
|---|---|
| substrate cycle | <biochemistry> Any seqence of enzyme catalysed reactions in which the forward and reverse processes (catalysed by different enzymes) are consititutively active. Frequently used to describe the cycle of phosphorylation and dephosphorylation of phosphatidyl inositol derivatives in cell membranes. (05 Jan 1998) |
| succinic acid cycle | A series of oxidation reduction reactions in which succinic acid and other 4-carbon atoms acids (fumaric, malic, oxaloacetic) take part in the oxidation of pyruvic acid as part of the tricarboxylic acid cycle. See: dicarboxylic acid cycle. (05 Mar 2000) |
| dicarboxylic acid cycle | That portion of the tricarboxylic acid cycle involving the dicarboxylic acids (succinic, fumaric, malic, and oxaloacetic acids), a cyclic scheme in which certain steps of the tricarboxylic acid cycle are used with the glyoxylate cycle; important in the utilization of glyoxylic acid in microorganisms. (05 Mar 2000) |
| direct life cycle | <epidemiology> A life cycle in which a parasite is transmitted directly from one host to the next without an intermediate host or vector of another species. (05 Dec 1998) |
| indirect life cycle | <epidemiology> A life cycle which requires one or more intermediate hosts before the definitive host species is reinfected. Compare direct, nondirect. (05 Dec 1998) |
| isometric period of cardiac cycle | That period in which the muscle fibres do not shorten although the cardiac muscle is excited and the pressure in the ventricles rises, extending from the closure of the atrioventricular valves to the opening of the semilunar valves (isovolumic constriction) or the reverse (isovolumic relaxation). (05 Mar 2000) |
| ornithine cycle | The metabolic pathway isfound in vertebrates and takes place in theliver, in it, urea is synthesised from amino acids and carbon dioxide. (09 Oct 1997) |
| ovarian cycle | The normal sex cycle which includes development of an ovarian (graafian) follicle, rupture of the follicle with discharge of the ovum, and formation and regression of a corpus luteum. (05 Mar 2000) |
| TCA cycle | <biochemistry> The central feaure of oxidative metabolism. Cyclic reactions whereby acetyl CoA is oxidized to carbon dioxide providing reducing equivalents (NADH or FADH2) to power the electron transport chain. Also provides intermediates for biosynthetic processes. (16 Dec 1997) |
| topping cycle | A cogeneration system in which electric power is produced first. The reject heat from power production is then used to produce useful process heat. (05 Dec 1998) |
| endogenous cycle | The portion of a parasitic life cycle occurring within the host. (05 Mar 2000) |
| tricarboxylic acid cycle | <biochemistry> The central feaure of oxidative metabolism. Cyclic reactions whereby acetyl CoA is oxidized to carbon dioxide providing reducing equivalents (NADH or FADH2) to power the electron transport chain. Also provides intermediates for biosynthetic processes. (16 Dec 1997) |
| estrous cycle | The series of physiologic uterine, ovarian, and other changes that occur in higher animals, consisting of proestrus, estrus, postestrus, and anestrus or diestrus. (05 Mar 2000) |
| estrus cycle | A reproductive cycle in some female mammals (but not female humans, who instead have menstrual cycles). The cycle is characterised by a short period of intense sexual desire (called estrus or heat) when the animal is fertile, which often occurs only once or twice a year, and involves correlating physical changes of the reproductive tract. (09 Oct 1997) |