| 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) |
| thumb fractures | <radiology> Base of 1st metacarpal, Bennett ULNAR side, Rolando RADIAL side (mnemonic R=R), base of 1st proximal phalanx, Gamekeeper avulsion fracture (12 Dec 1998) |
| tooth fractures | Break or rupture of a tooth or tooth root. (12 Dec 1998) |
| 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) |
| jaw fractures | Fractures of the upper or lower jaw. (12 Dec 1998) |
| ulna fractures | Fractures of the larger bone of the forearm. (12 Dec 1998) |
| unstable cervical spine fractures | <radiology> Flexion: bilateral interfacetal dislocation, flexion teardrop fracture (usually C5 or C6) extension: extension teardrop fracture (usually C2 or C3), hangman's fracture, extension-dislocation, extension-fracture-dislocation, odontoid fracture vertical compression: Jefferson burst fracture see: cervical spine fractures (12 Dec 1998) |
| femoral fractures | Fractures of the femur. (12 Dec 1998) |
| femoral neck fractures | Fractures of the short, constricted portion of the thigh bone between the femur head and the trochanters. It excludes intertrochanteric fractures which are hip fractures. (12 Dec 1998) |
| zygomatic fractures | Fractures of the zygoma. (12 Dec 1998) |