| gamma radiation | Ionizing electromagnetic radiation resulting from nuclear processes, such as radioactive decay or fission. (05 Mar 2000) |
|---|---|
| gamma ray | <radiobiology> Electromagnetic radiation (photons) with energies greater than (roughly) 100 keV (that is, 100,000 electron volts). Gamma radiation frequently accompanies alpha and beta decays, and always accompanies fission. Gamma rays are highly penetrating and are best shielded against using dense materials, such as lead or depleted uranium. (Gamma rays are similar to X-rays, but are generally higher in energy and nuclear in origin.) Gamma rays have wavelengths of 1 nanometre or shorter. These are highly energised, deeply penetrating photons which can be emitted from an atomic nucleus during nuclear fission (the splitting of an atom) and during regular atomic decay (radioactivity). (13 Oct 1997) |
| gamma ray knife | A beam of high energy X-rays. See: radiosurgery. (05 Mar 2000) |
| gamma rays | Very powerful and penetrating, high-energy electromagnetic radiation of shorter wavelength than that of X-rays. They are emitted by a decaying nucleus, usually between 0.01 and 10 mev. They are also called nuclear X-rays. (12 Dec 1998) |
| gamma subunit, cGMP phosphodiesterase | <enzyme> Isolated from canine retinal rod photoreceptor cells; genbank u49359 Registry number: EC 3.1.14.- Synonym: pde-gamma, pdegamma, cgmp-pde gamma subunit (26 Jun 1999) |
| gamma-tocopherol | 7,8-Dimethyltocol;a form biologically less active than alpha-gamma-tocopherol (05 Mar 2000) |
| gamma-tocopherol methyltransferase | <enzyme> Forms alpha-tocopherol; enzyme nomenclature name of tocopherol o-methyltransferase is incorrect, since there are no -och3 groups in the product Registry number: EC 2.1.1.95 Synonym: gtc methyltransferase (26 Jun 1999) |
| gamma-tolerance | The tolerance of a person or a piece of equipment to forces that develop as a result of acceleration or deceleration. (05 Mar 2000) |
| gamma toxin | <microbiology> Complex toxin (33.4 kD) produced by Staphylococcus aureus. Rabbit erythrocytes are particularly sensitive to lysis by the toxin, but the mechanism is unknown. (18 Nov 1997) |
| gene rearrangement, gamma-chain T-cell antigen receptor | Ordered rearrangement of T-cell variable gene regions coding for the gamma-chain of antigen receptors. (12 Dec 1998) |
| genes, T-cell receptor gamma | DNA sequences encoding the gamma chain of the T-cell receptor. The human gamma-chain locus is organised similarly to the tcr beta-chain locus. (12 Dec 1998) |
| receptors, antigen, T-cell, gamma-delta | T-cell receptors composed of CD3-associated gamma and delta polypeptide chains and expressed primarily in CD4-/CD8- T-cells. The receptors appear to be preferentially located in epithelial sites and probably play a role in the recognition of bacterial antigens. The T-cell receptor gamma/delta chains are separate and not related to the gamma and delta chains which are subunits of CD3 (see antigens, CD3). (12 Dec 1998) |
| glutamate gamma-saemialdehyde | -OOCCH(NH3)+CH2CH2C HO;an intermediate in l-proline and l-ornithine metabolism; becomes elevated in type II hyperprolinaemia. (05 Mar 2000) |
| motor neurons, gamma | Motor neurons which activate the contractile regions of intrafusal muscle fibres, thus adjusting the sensitivity of the muscle spindles to stretch. Gamma motor neurons may be "static" or "dynamic" according to which aspect of responsiveness (or which fibre types) they regulate. The alpha and gamma motor neurons are often activated together (alpha gamma coactivation) which allows the spindles to contribute to the control of movement trajectories despite changes in muscle length. (12 Dec 1998) |
| poly(gamma-glutamic acid) | A polypeptide formed of glutamic acid residues, the gamma-carboxyl group of one glutamic acid being condensed to the amino group of its neighbor; occurs naturally in the anthrax bacillus capsule. (05 Mar 2000) |