| 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) |
| oxidative | Having the power to oxidise; denoting a process involving oxidation. (05 Mar 2000) |
| oxidative metabolism | Respiration in the biochemical sense. (18 Nov 1997) |
| oxidative phosphorylation | <biochemistry> The phosphorylation of ATP coupled to the respiratory chain. (18 Nov 1997) |
| oxidative stress | A highly oxidized environment within cells that is thought to promote HIV replication because cells are forced into a highly activated state due to loss of control of their regulatory systems. (09 Oct 1997) |
| oxide | <chemistry> Any element (but especially a metal) that has formed a binary compound with oxygen. (09 Oct 1997) |
| oxides | <chemistry> Binary compounds of oxygen containing the anion o(2-). The anion combines with metals to form alkaline oxides and non-metals to form acidic oxides. (12 Dec 1998) |
| oxidise | <chemistry> To combine or cause an element or radical to combine with oxygen or to lose electrons. (05 Mar 2000) |
| oxidised cellulose | <surgery> Cellulosic acid in the form of an absorbable gauze which is used as a haemostatic in operations where ligation is not feasible (capillary or venous bleeding from small vessels) because cellulosic acid has a pronounced affinity for haemoglobin and produces an artificial clot. It is a sterile absorbable substance prepared by the oxidation of cotton containing not less than 16% and not more than 22% of carboxyl. See: oxycellulose. (22 Sep 2002) |
| oxidised glutathione | <biochemistry> Glutathione acting in cells as a hydrogen acceptor; reduced by glutathione reductase. (05 Mar 2000) |
| oxidize | <chemistry> To combine with oxygen, or subject to the action of oxygen, or of an oxidizing agent. Specifically: To combine with oxygen or with more oxygen; to add oxygen to; as, to oxidize nitrous acid so as to form nitric acid. To remove hydrogen from (anything), as by the action of oxygen; as, to oxidize alcohol so as to form aldehyde. To subject to the action of oxygen or of an oxidizing agent, so as to bring to a higher grade, as an -ous compound to an -ic compound; as, to oxidize mercurous chloride to mercuric chloride. In certain cases to oxidize is identical with to acidify; for, in nearly all cases, the more oxygen a substance contains the more nearly does it approximate to acid qualities; thus, by oxidation many elements, as sulphur, nitrogen, carbon, chromium, manganese, etc, pass into compounds which are acid anhydrides, and thus practically in the acid state. Origin: Oxidized; Oxidizing. Source: Websters Dictionary (01 Mar 1998) |
| oxidized rhizosphere | Oxidized channels and soil surrounding living roots and rhizomes in plants. (09 Oct 1997) |
| oxidizer | <chemistry> An agent employed in oxidation, or which facilitates or brings about combination with oxygen; as, nitric acid, chlorine, bromine, etc, are strong oxidizers. Source: Websters Dictionary (01 Mar 1998) |