| fast neutrons | Neutrons, the energy of which exceeds some arbitrary level, usually around one million electron volts. (12 Dec 1998) |
|---|---|
| fast pyrolysis | Thermal conversion of biomass by rapid heating to between 450> To 600>C in the absence of oxygen. (05 Dec 1998) |
| fast ray | <microscopy> The fast ray or fast component for a crystal or fibre corresponds to the lower refractive index. (05 Aug 1998) |
| fast smear | A cytologic smear containing material from the vaginal pool and pancervical scrapings, mixed and prepared on one microscopic slide, smeared, and fixed immediately; used principally for routine screening of ovaries, endometrium, cervix, vagina, and hormonal states. (05 Mar 2000) |
| Kluver-Barrera Luxol fast blue stain | <technique> In combination with cresyl violet, a stain useful for demonstrating myelin and Nissl substance. (05 Mar 2000) |
| liquid-metal fast-breeder reactor | <physics> Fission breeder reactor concept using liquid-metal coolant and breeding additional fuel off fast neutrons. See: breeder reactor. (09 Oct 1997) |
| Luxol fast blue | Name for a group of closely related copper phthalocyanin dyes used as stains (with PAS, PTAH, haematoxylin, silver nitrate, etc.) for myelin in nerve fibres. (05 Mar 2000) |
| calcium channel | <physiology> A membrane channel that is specific for calcium. It is a voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorised as l, t, n, or p types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. (12 May 2002) |
| calcium channel agonist | <pharmacology> Agents that increase calcium influx into calcium channels of excitable tissues. This causes vasoconstriction in vascular smooth muscle and/or cardiac muscle cells as well as stimulation of insulin release from pancreatic islets. Therefore, tissue-selective calcium agonists have the potential to combat cardiac failure and endocrinological disorders. They have been used primarily in experimental studies in cell and tissue culture. (12 Dec 1998) |
| calcium channel antagonist | <pharmacology> A class of drugs that act by selective inhibition of calcium ion influx through or across cell membranes or on the release and binding of calcium in intracellular pools. Calcium channel blockers are used primarily in the treatment of certain heart conditions and stroke. As they are inducers of vascular and other smooth muscle relaxation, they are also used in the treatment of hypertension and cerebrovascular spasms, as myocardial protective agents, and in the relaxation of uterine spasms. Synonym: calcium antagonist, calcium channel-blocker, slow channel-blocking agent. (12 May 2002) |
| calcium channel-blocker | <pharmacology> A class of drugs that act by selective inhibition of calcium ion influx through or across cell membranes or on the release and binding of calcium in intracellular pools. Calcium channel blockers are used primarily in the treatment of certain heart conditions and stroke. As they are inducers of vascular and other smooth muscle relaxation, they are also used in the treatment of hypertension and cerebrovascular spasms, as myocardial protective agents, and in the relaxation of uterine spasms. Synonym: calcium antagonist, calcium channel-blocker, slow channel-blocking agent. (12 May 2002) |
| gated ion channel | <physiology> Transmembrane proteins of excitable cells, that allow a flux of ions to pass only under defined circumstances. Channels may be either voltage gated, such as the sodium channel of neurons or ligand gated such as the acetylcholine receptor of cholinergic synapses. Channels tend to be relatively ion specific and allow fluxes of typically 1000 ions to pass in around 1ms, they are thus much faster at moving ions across a membrane than transport ATPases. (05 May 1997) |
| voltage-gated channel | A class of ion channel's that open and close in response to change in the electrical potential across the plasma membrane of the cell; voltage-gated Na+ c.'s are important for conducting action potential along nerve cell processes. (05 Mar 2000) |
| voltage gated ion channel | <physiology> A transmembrane ion channel whose permeability to ions is extremely sensitive to the transmembrane potential difference. These channels are essential for neuronal signal transmission and for intracellular signal transduction. See: sodium channel. (18 Nov 1997) |
| channel | A furrow, gutter, or groovelike passageway. See: canal. Origin: L. Canalis (05 Mar 2000) |