| Schmorl's ferric-ferricyanide reduction stain | <technique> A stain to test for reducing substances in tissues, including melanin, argentaffin granules, thyroid colloid, keratin, keratohyalin, and lipofuscin pigments; ferricyanide is converted into ferrocyanide which is converted to insoluble Prussian blue in the presence of ferric ions. (05 Mar 2000) |
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| selective reduction | <obstetrics> A technique for intrauterine termination of one or more foetuses while leaving one or more foetuses undisturbed, usually in pregnancies with foetal anomalies or with multiple gestations. (05 Mar 2000) |
| source emission reduction plan | (SERP) A contingency plan developed to reduce emissions during an air quality emergency. (05 Dec 1998) |
| nitroblue tetrazolium reduction | <chemical> Nitroblue tetrazolium, a yellow dye, is taken up by phagocytosing neutrophils and reduced to insoluble formazan, which is deep blue, if the metabolic burst is normal. Reduction does not take place in chronic granulomatous disease. (18 Nov 1997) |
| internal reduction | The relocation of a joint or realignment of a fracture through a surgical incision. most internal reductions utilise general anaesthesia. (27 Sep 1997) |
| oxidation-reduction | A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs. (12 Dec 1998) |
| oxidation-reduction electrode | An electrode capable of measuring oxidation-reduction potential. See: quinhydrone electrode. Synonym: redox electrode. (05 Mar 2000) |
| oxidation-reduction indicator | A substance that undergoes a definite colour change at a specific oxidation potential. Synonym: redox indicator. (05 Mar 2000) |
| oxidation-reduction potential | <chemistry, physics> The potential in volts of an inert metallic electrode measured in a system of an arbitrarily chosen ratio of [oxidant] to [reductant] and referred to the normal hydrogen electrode at absolute temperature. It is calculated from the following equation: where R is the gas constant expressed in electrical units, T the absolute temperature (Kelvin), n the number of electrons transferred, F the faraday and E0 the normal symbol for the potential of the system at pH 0; for biological systems E0' is often used (in which pH = 7). Compare: Nernst's equation. Synonym: redox potential. (05 Mar 2000) |
| oxidation-reduction reaction | <chemistry> Any reaction in which electrons are removed from one molecule or atom and given to another molecule or atom. (09 Oct 1997) |
| oxidation-reduction system | <enzyme> An enzyme system in the tissues by which oxidation and reduction proceed simultaneously through the transference of hydrogen or of one or more electrons from one metabolite to another. See: oxidation-reduction. Synonym: redox system. (05 Mar 2000) |
| tuberosity reduction | The surgical excision of excessive fibrous or bony tissue in the area of the maxillary tuberosity prior to the construction of prosthetic appliances. (05 Mar 2000) |
| biopsy, open lung | <investigation, procedure, surgery> A procedure which involves the removal of a small specimen of lung tissue for microscopic analysis via a surgical incision in the chest wall. This test can be used to identify a variety of lung cancers, lung infections and lung diseases. (21 Mar 1998) |
| reading frame, open | An open reading frame in DNA has no termination codon, no signal to stop reading the nucleotide sequence, and so may be translated into protein. (12 Dec 1998) |
| glaucoma, open-angle | Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris. (12 Dec 1998) |