| 5 beta-cholestane-3 alpha,7 alpha-diol 26-hydroxylase | <enzyme> Nadp-dependent Registry number: EC 1.14.13.- (26 Jun 1999) |
|---|---|
| 7 alpha-hydroxy-4-cholesten-3-one-12 alpha monooxygenase | <enzyme> Liver microsomal enzyme active in conversion of cholesterol to cholic acid; introduces a 12 alpha-hydroxyl group into the steroid nucleus of cholesterol Registry number: EC 1.14.99.- Synonym: 7-hco-monooxygenase, hco 12 alpha-hydroxylase (26 Jun 1999) |
| actinic ray | A light ray toward and beyond the violet end of the spectrum that acts upon a photographic plate and produces other chemical effects. Synonym: chemical ray. (05 Mar 2000) |
| ap, X-ray | An X-ray picture in which the beams pass from front-to-back (anteroposterior). As opposed to a PA (posteroanterior) film in which the rays pass through the body from back-to-front. (12 Dec 1998) |
| beta ray | 1. <radiobiology> Original term used for electrons (and positrons) ejected from decaying nuclei via beta emission. (Label derives from the old days when we had various kinds of radiation emission, and they were labelled alpha, beta, and gamma (the first letters of the Greek Alphabet) because no one really knew what any of them were.) 2. A stream of positive or negative electrons ejected with high energy from a disintegrating atomic nucleus; most biomedically used isotopes emit negative particles (electrons or negatrons, rather than positrons). Cathode rays are low-energy negative electrons produced in cathode ray tubes, also called television tubes or oscilloscopes. (12 Sep 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) |
| panoramic X-ray | <dentistry> An X-ray taken by a machine that rotates around your head to give the orthodontist a picture of your teeth, jaws and other important information. (08 Jan 1998) |
| panoramic X-ray film | In dentistry, a radiograph taken to give a panoramic view of the entire upper and lower dental arch as well as the temporomandibular joints. (05 Mar 2000) |
| ray | <botany> A zygomorphic flower in the family Asteraceae, a radial band of cells traversing the conducting elements in woody stems. Of a compound umbel, one of the first (lower) series of branches of the inflorescence main stem. (09 Oct 1997) |
| ray grass | <botany> A perennial European grass (Lolium perenne). Synonym: rye grass, and red darnel. See Darnel, and Grass. Italian ray, or rye, grass. See Darnel, and Grass. Origin: Etymol. Of ray is uncertain. Source: Websters Dictionary (01 Mar 1998) |
| ray, light | <microscopy> The term applied to the lines perpendicular to the wavefronts of waves of light to indicate their direction of travel in an isotropic medium. Note the wave normal and the ray do not coincide in isotropic media. (05 Aug 1998) |
| ray therapeutics | An obsolete term for radiotherapy. (05 Mar 2000) |
| mass chest X-ray | X-ray screening of large groups of persons for diseases of the lung and heart by means of radiography of the chest. (12 Dec 1998) |
| reflected ray | A ray of light or other form of radiant energy which is thrown back from a nonpermeable or nonabsorbing surface; the ray which strikes the surface before reflection is the incident ray. (05 Mar 2000) |