| DAS | dead air space; Death Anxiety Scale; delayed anovulatory syndrome; dextroamphetamine sulfate; digita... |
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| DAT | delayed-action tablet; dementia Alzheimer's type; dental aptitude test; diacetylthiamine; diet as to... |
| DCH | delayed cutaneous hypersensitivity; Diploma in Child Health |
| DCN | data collection network; deep cerebral nucleus; delayed conditioned necrosis; depressed, cognitively... |
| DED | date of expected delivery; defined exposure dose; delayed erythema dose |
| delayed reaction experiment | A method of measuring memory: a stimulus is presented and removed before the organism is permitted to respond to it; the interval during which the stimulus is absent, providing the organism responds correctly, is an indication of the length of memory. (05 Mar 2000) |
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| delayed rectifier channel | <physiology> The potassium selective ion channels of axons, so called because they change the potassium conductance with a delay after a voltage step. The name is used to denote any axon like K channel. Various roles for example regulation of pacemaker potentials, generation of bursts of action potentials or generation of long plateaus on action potentials. (18 Nov 1997) |
| delayed reflex | A reflex in which a little time elapses between stimulus and response. See: trace conditioned reflex. (05 Mar 2000) |
| delayed sensation | A sensation that is not perceived until the lapse of an appreciable interval following the application of the stimulus. General sensation, a sensation referred to the body as a whole rather than to any particular part. (05 Mar 2000) |
| delayed suture | A suturing of a wound after an interval of days. (05 Mar 2000) |
| delayed type hypersensitivity | <immunology> Hypersensitivity (increased reaction by the body to a foreign substance such as an antigen or allergen) that does not appear until 24 to 48 hours after the body is exposed to the foreign substance. (09 Oct 1997) |
| ovum implantation, delayed | Delay of embryonal development whereby the blastocyst remains in the uterine cavity for a variable period of time before attaching to the endometrium and continuing its development. (12 Dec 1998) |
| abscopal effect | A reaction produced following irradiation but occurring outside the zone of actual radiation absorption. (05 Mar 2000) |
| additive effect | <biochemistry, chemistry> An additive effect is the overall biological effect two chemicals acting together and which is the simple sum of the effects of the chemicals acting independently. Compare: antagonism. (15 Jan 1998) |
| adverse effect | This is an abnormal or harmful effect to an organism caused by exposure to a chemical. It is indicated by some result such as death, a change in food or water consumption, altered body and organ weights, altered enzyme levels, or visible illness. An effect may be classed as adverse if it causes functional or anatomical damage, causes irreversible change in the homeostasis of the organism, or increases the susceptibility of the organism to other chemical or biological stress. A non-adverse effect will usually be reversed when the organism is no longer being exposed to the chemical. (09 Oct 1997) |
| Anrep effect | A small transient positive inotropic effect of abrupt increases of systolic aortic and left ventricular pressures related to recovery from transient subendocardial ischemia (e.g., cold pressor test). (05 Mar 2000) |
| antagonistic effect | This is the consequence of one chemical (or group of chemicals) counteracting the effects of another chemical, the opposing chemicals cancel out each other's effects. (09 Oct 1997) |
| Arias-Stella effect | Focal, unusual, decidual changes in endometrial epithelium, consisting of intraluminal budding, and nuclear enlargement and hyperchromatism with cytoplasmic swelling and vacuolation; may be associated with ectopic or uterine pregnancy. Synonym: Arias-Stella effect, Arias-Stella reaction. (05 Mar 2000) |
| Auger effect | <physics> Transition of an electron in an atom from a discrete electronic level to an ionised continuous level with the same energy. Synonym: autoionisation. (13 Jan 1998) |
| autokinetic effect | In psychology, the apparent drifting about of a small, fixed, spot of light which is being observed in a dark room. (05 Mar 2000) |