| alpha cells of anterior lobe of hypophysis | Acidophil cell's that constitute about 35% of the cell's of the anterior lobe. There are two varieties: one that elaborates somatotropin, another that elaborates prolactin. (05 Mar 2000) |
|---|---|
| alpha cells of pancreas | Cell's of the islets of Langerhans that secrete glucagon. (05 Mar 2000) |
| alpha chain disease | A vague or indefinite term; could be used for alpha-heavy-chain disease (a lymphoplasma cell proliferative disease usually seen in Mediterranean men, characterised by intestinal involvement with steatorrhoea, often progressive with fatal outcome) or a thalassaemia (a genetic abnormality in the alpha globin chain of haemoglobin). (05 Mar 2000) |
| alpha channeling | <radiobiology> Term for an idea (so far theoretical) in magnetic confinement fusion, the idea is that plasma waves can be used to control the alpha particles produced in a fusion reactor, to transfer their energy directly to fuel ions, and to help push them out of the plasma. This could potentially help to substantially improve the power output capabilities of fusion plasmas. (09 Oct 1997) |
| alpha emission | <physics> Form of nuclear decay where the nucleus emits an alpha particle (see entry below). (09 Oct 1997) |
| alpha error | The statistical error (said to be of the first kind or type I) made in testing an hypothesis when it is concluded that a result is positive when it really is not. Alpha error is often referred to as a false positive. (12 Dec 1998) |
| alpha fibres | Large somatic motor or proprioceptive nerve fibre's conducting impulses at rates near 100 m/sec. (05 Mar 2000) |
| alpha glucosidase | <enzyme> An enzyme which removes the last 1,4-linked alpha-D-glucose residue from the nonreducing end of a long chain (or polymer) of such residues, making an alpha-D-glucose molecule out of it in the process. (09 Oct 1997) |
| alpha granule | A granule of an alpha cell that was named as the first of several kinds or because it was acidophilic. (05 Mar 2000) |
| alpha helix | <molecular biology> A particular helical folding of the polypeptide backbone in protein molecules (both fibrous and globular), in which the carbonyl oxygens are all hydrogen bonded to amide nitrogen atoms three residues along the chain. The translation of amino acid residues along the long axis is 0.15 nm and the rotation per residue, 100 |
| alpha interferon | <cytokine> Interferon which is released by leukocytes in response to a viral infection. A protein cytokine that is used as an anticancer agent. (15 Nov 1997) |
| alpha methyl dopa | <drug> An antihypertensive drug, preferred in pregnant patients. (18 Nov 1997) |
| alpha mucase | <chemical> Combination of mucopolysaccharidases and chymotrypsin (26 Jun 1999) |
| alpha particle | <physics> A radioactive particle made up of two protons and two neutrons, these particles are created by the decay of a radioactive material or by nuclear bombardment, and they are the same as the nucleus of a helium-4 atom. (09 Oct 1997) |
| alpha particles | Positively charged particles composed of two protons and two neutrons, i.e., helium nuclei, emitted during disintegration of very heavy isotopes; a beam of alpha particles or an alpha ray has very strong ionizing power, but weak penetrability. (12 Dec 1998) |