| S value | Svedberg Unit. See: sedimentation coefficient. (18 Nov 1997) |
|---|---|
| iodine value | An indication of the quantity of unsaturated fatty acids present in a fat; it represents the number of grams of iodine absorbed by each 100 g of fat. See: hydrogen number. Synonym: iodine value. (05 Mar 2000) |
| tenth-value layer | <radiobiology> Thickness of a specified substance which, when introduced into the path of a given beam of radiation, reduces the absorbed dose index or dose-equivalent index to one-tenth. The magnitude of the tenth-value layer may be different for absorbed dose index and dose equivalent index. (16 Dec 1997) |
| thiocyanogen value | The number of grams of thiocyanogen taken up by 100 g of fat; analogous to the iodine number, except that thiocyanogen will not add to all the double bonds in polyunsaturated fatty acids as will iodine. Synonym: thiocyanogen value. (05 Mar 2000) |
| threshold limit value | The maximum concentration of a chemical recommended by the American Conference of Government Industrial Hygienists for repeated exposure without adverse health effects on workers. (05 Mar 2000) |
| economic value of life | The evaluation of the monetary value of a life lost or a life saved. (12 Dec 1998) |
| law of initial value | The direction of response of a body function to any agent depends to a large degree on the initial level of that function. Synonym: law of initial value. (05 Mar 2000) |
| lower heating value | (LHV) The potential energy in a fuel if the water vapour from combustion of hydrogen is not condensed. (05 Dec 1998) |
| bis-gamma-glutamylcystine reductase | <enzyme> From halobacterium halobium; specific for NADPH Registry number: EC 1.6.4.- Synonym: bis-ggc reductase (26 Jun 1999) |
| gamma | <physics> Third letter in the Greek alphabet, variable used for a number of things in physics, in plasma physics gamma is often used as the variable for growth rates of instabilities. (09 Oct 1997) |
| gamma-Abu | gamma-aminobutyric acid |
| gamma alcoholism | Jellinek's term for a severe stage of alcoholism characterised by a progression from psychological to physiological dependence upon alcohol, including tissue dependence and withdrawal symptoms, with loss of control over alcohol intake and destructive effects on interpersonal relationships. (05 Mar 2000) |
| gamma aminobutyric acid | <biochemistry> An important amino acid which functions as the most prevalent inhibitory neurotransmitter in the central nervous system. Gamma aminobutyric acid works in partnership with a derivative of Vitamin B-6, pyridoxine, to cross from the axons to the dendrites through the synaptic cleft, in response to an electrical signal in the neuron and inhibits message transmission. This helps control the nerve cells from firing too fast, which would overload the system. The action of gamma aminobutyric acid decreases epileptic seizures and muscle spasms by inhibiting electrical signals in this manner. Studies have shown that the site of action in the brain of benzodiazepams, including Valium, is directly coupled to the brain receptor for gamma aminobutyric acid. Acronym: GABA (05 Jan 1998) |
| gamma aminobutyric acid receptor | <physiology> Ligand gated chloride ion channel forming receptor opened by gamma aminobutyric acid. Two distinct types: A and B. A receptor: One of a family of neurotransmitter receptors with fast intrinsic ion channels that includes the glycine receptor and the nicotinic acetylcholine receptor. Distinct from another major receptor family, the muscarininc acetylcholine receptor and rhodopsin, with no intrinsic ion channel. The A receptor is specifically blocked by bicuculline. It consists of two pairs of protein chains forming an A2B2 complex, the A chains bind benzodiazepine and the B chains bind GABA. The 4 subunits are thought to form a tight group with the chloride channel in the middle. There is considerable similarity between the amino acid sequences of the receptor subunits and those of the nicotinic acetylcholine receptor suggesting that both receptors are derived from some evolutionary ancestor. See: amino acid receptor superfamily. B receptor: Brain receptor (80 kD) for the inhibitory neurotransmitter gamma amino butyric acid. Differs from the A receptor both in agonist specificity (baclofen is a specific agonist) and its effects on cells. It modulates intracellular calcium levels through a Go mediated effect on N type calcium channels and also lowers intracellular cAMP levels by an effect on adenylyl cyclase, thereby reducing the secretion of catecholamines. (05 Jan 1998) |
| gamma-amylase | A hydrolase removing terminal alpha-1,4-linked d-glucose residues from nonreducing ends of chains, with release of beta-d-glucose. Synonym: acid maltase, amyloglucosidase, gamma-amylase, glucoamylase. (05 Mar 2000) |