| 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) |
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| 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) |
| Abbott's stain | <technique> Spores are stained blue with alkaline methylene blue; bodies of the bacilli become pink with eosin counterstain. (05 Mar 2000) |
| aceto-orcein stain | <technique> A stain used for chromosomes in air-dried or squashed cytologic material. (05 Mar 2000) |
| acid-fast stain | <technique> A staining technique used to determine the cell wall property of a microorganism. After stained with dye such as hot carbolfuschin, an acid-fast organism, (for example Mycobacterium species) will retain the colour in its cell wall after being washed with acid-alcohol. (13 Nov 1997) |
| acid stain | <technique> A dye in which the anion is the coloured component of the dye molecule, e.g., sodium eosinate (eosin). (05 Mar 2000) |
| Ag-AS stain | <technique> A stain for the acid protein component of nucleolar regions which are active or which were transcriptionally active in the preceding interphase; uses silver nitrate, ammoniacal silver, and formalin. Synonym: Ag-AS stain. (05 Mar 2000) |
| Albert's stain | <technique> A stain for diphtheria bacilli and their metachromatic granules; contains toluidine blue, methyl green, glacial acetic acid, alcohol, and distilled water. (05 Mar 2000) |
| Altmann's anilin-acid fuchsin stain | <technique> A mixture of picric acid, anilin, and acid fuchsin which stains mitochondria crimson against a yellow background. (05 Mar 2000) |
| auramine O fluorescent stain | <technique> A rapid and accurate technique for Mycobacterium tuberculosis, using auramine O-phenol and a methylene blue counterstain. (05 Mar 2000) |
| basic fuchsin-methylene blue stain | <technique> A stain for intact epoxy sections; semi-thick sections of plastic-embedded tissues have nuclei stained purple; collagen, elastic lamina, and connective tissue are stained blue; mitochondria, myelin, and lipid droplets are stained red; cytoplasm, smooth muscle cells, axoplasm, and chrondroblasts are stained pink. (05 Mar 2000) |
| basic stain | <technique> A dye in which the cation is the coloured component of the dye molecule that binds to anionic groups of nucleic acids (PO4≡) or acidic mucopolysaccharides (e.g., chondroitin sulfate). (05 Mar 2000) |
| Bauer's chromic acid leucofuchsin stain | <technique> A stain for glycogen and fungi utilizing chromic acid as an oxidizing agent of polysaccharides, followed by Schiff's reagent; glycogen and fungi cell walls appear deep red. (05 Mar 2000) |