| 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) |
| chemiluminescence | <chemistry> Light emitted as a reaction proceeds. Becoming used increasingly to assay ATP (using firefly luciferase) and the production of toxic oxygen species by activated phagocytes (using luminol or lucigenin as bystander substrates that release light when oxidized). See: bioluminescence. (18 Nov 1997) |
| chemiluminescence assays | Including a subcategory using bioluminescence (biologically derived chemiluminescence agents), use the generation of light from oxidative chemical reactions as an indicator of the quantity of unbound luminescent labelled antigen. This allows quantitation of unlabelled antigen from patient specimens in a variety of homogeneous (single phase) or heterogeneous (multiple phase) immunoassay techniques. (05 Mar 2000) |