| chemical repair | Conversion of a free radical to a stable molecule. (05 Mar 2000) |
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| chemical sampling | A sample that is obtained by whatever means is convenient and then purified of irrelevant elements before analysis; the assumption of thorough mixing is not necessary. (05 Mar 2000) |
| chemical sequencing | A lab technique used to determine the sequence of nucleotides in a DNA molecule. The DNA molecule is labelled with radioactive phosphorous (chemical element P), cut into fragments, and analysed through electrophoresis. (09 Oct 1997) |
| chemical shift | Dependence of the resonance frequency of a nucleus on the chemical binding of the atom or molecule in which it is contained. See: chemical shift artifact. (05 Mar 2000) |
| chemical shift artifact | In magnetic resonance imaging, a dark band caused by a biochemical difference in resonant frequency of adjacent regions rather than a true anatomic separation. (05 Mar 2000) |
| chemical solution | See: solution. (05 Mar 2000) |
| chemical sympathectomy | Destruction of the periareterial sympathetic nerves, as in Doppler's operation, by a corrosive such as phenol. (05 Mar 2000) |
| chemical synapse | <physiology> A nerve nerve or nerve muscle junction where the signal is transmitted by release from one membrane of a chemical transmitter that binds to a receptor in the second membrane. Importantly, signals only pass in one direction. (18 Nov 1997) |
| chemical synergism | Interaction of chemicals in a mixture to produce a greater toxic effect than would be expected from the sum of the toxicities of the individual chemicals. (09 Oct 1997) |
| chemical taxonomy | An approach to the classification of organisms based on the distribution of natural products. (05 Mar 2000) |
| chemical warfare | Tactical warfare using incendiary mixtures, smokes, or irritant, burning, or asphyxiating gases. (12 Dec 1998) |
| chemical warfare agents | Chemicals that are used to cause the disturbance, disease, or death of humans during war. (12 Dec 1998) |
| chemically cured resin | A resin which contains an initiator, usually benzoyl peroxide, and an activator, usually a tertiary amine, in separate pastes. When mixed, the amine reacts with the benzoyl peroxide to form free radicals and polymerization occurs. (05 Mar 2000) |
| chemiclave | A machine that sterilises surgical instruments with high-pressure, high-temperature water vapor, alcohol vapor, and formaldehyde vapor. (09 Oct 1997) |
| chemicocautery | Any substance that destroys tissue upon application. Synonym: chemical cautery, chemicocautery. (05 Mar 2000) |