| Stiles-Crawford effect | Light that enters through the centre of the pupil produces a greater visual effect than light that enters obliquely. (05 Mar 2000) |
|---|---|
| no-observed-adverse-effect level | The highest dosage administered that does not produce toxic effects. The noael will depend on how closely dosages are spaced (lowest-observed-adverse-effect level and no-observed-effect level) and the number of animals examined. The ultimate objective is usually to determine not the "safe" dosage in laboratory animals but the "safe" dosage for humans. Therefore, the extrapolation most often required of toxicologists is from high-dosage studies in laboratory animals to low doses in humans. (casarett and doull's toxicology: the basic science of poisons, 4th ed) (12 Dec 1998) |
| nuclear Overhauser effect | <enzyme> An enzyme seen in nuclear magnetic resonance in which there is a through-space nearest neighbor interaction. (05 Mar 2000) |
| synergistic effect | The doctrine or theory, attributed to Melanchthon, that in the regeneration of a human soul there is a cooperation, or joint agency, on the part both of God and of man. See: Synergetic. Source: Websters Dictionary (01 Mar 1998) |
| doppler effect | <radiobiology> Variation in the frequency of a wave (as measured by an observer) due to relative motion between the observer and the source of the wave. (The observed frequency increases if the source is moving towards the observer and vice versa.) The equation can be found in most optics texts and many introductory physics texts. (09 Oct 1997) |
| dosage effect | The alteration of a phenotype by an increased dosage, or amount, of the product of the gene. (09 Oct 1997) |
| dose-effect curve | This is a graph drawn to show the relationship between the dose of a drug or other chemical and the magnitude of the graded effect that it produces. (09 Oct 1997) |
| drug side effect | An often undesirable effect that occurs in association with the use of a particular medication. Examples of common drug side effects include: nausea, vomiting, sedation, dizziness, headache and weakness. Drug side effects that occur in 1% or more, of patients taking a particular medication are considered to be causally related to the use of that medication. (27 Sep 1997) |
| Orbeli effect | The fatigue of a muscle stimulated by its nerve (i.e., indirectly) is reduced by concurrent stimulation of sympathetic fibres to the muscle; thought to be caused by norepinephrine diffusing from adrenergic fibres which innervate blood vessels in the muscle. (05 Mar 2000) |
| oxygen effect | Enhancement of radiosensitivity of cells in a high concentration of oxygen. (05 Mar 2000) |
| effect | The result produced by an action. (18 Nov 1997) |
| effect, founder | A population group with an unusual frequency of a gene due to there having been only a small number of original members ( founders ) one or more of whom had that gene. For example, the gene for Huntington disease was introduced into the Lake Maracaibo region of Venezuela early in the 19th century, so there are now over a hundred persons with Huntington disease and at least 900 persons at risk for that deadly disease in that region, the largest known aggregation known in the world with the Huntington gene. (12 Dec 1998) |
| effect modifier | A factor that modifies the effect of a putative causal factor under study; e.g., age is an effect modifier for many conditions. (05 Mar 2000) |
| effect modifiers | <epidemiology> Factors that modify the effect of the putative causal factor(s) under study. (12 Dec 1998) |
| electrophonic effect | The sensation of hearing produced when an alternating current of suitable frequency and magnitude is passed from an external source through a person. (05 Mar 2000) |