| light reactions | In photosynthesis, aseries of reactions in which light energy isconverted to chemical energy with the help of chlorophyll. ATP iscreated along with hydrogen ions and electrons as water molecules aresplit apart. (09 Oct 1997) |
|---|---|
| light reflex | A red glow reflected from the fundus of the eye when a light is cast upon the retina, as in retinoscopy. Synonym: eye reflex, fundus reflex, pupillary reflex. Synonym: pyramid of light. (05 Mar 2000) |
| light-repressible receptor protein kinase | <enzyme> Photo-regulated protein isolated from arabidopsis thaliana; genbank x97774 Registry number: EC 2.7.1.- Synonym: lrrpk gene product (26 Jun 1999) |
| light scattering | Particles suspended in a solution will cause scattering of light and the extent of the scattering is related to the size and shape of the particles (in a somewhat complex relationship). (18 Nov 1997) |
| light sense | The ability to perceive variations in the degree of light or brightness. (05 Mar 2000) |
| light sleep | A condition of half sleep. Synonym: light sleep. Origin: dys-+ G. Nystaxis, drowsiness (05 Mar 2000) |
| light treatment | Treatment with light. For example, a newborn with jaundice may be put under the lights. (12 Dec 1998) |
| light water | <radiobiology> Ordinary H2O, as opposed to heavy water, which contains atoms of the heavier isotopes of hydrogen, deuterium and/or tritium. See: hydrogen, isotope, deuterium, tritium, heavy water. (09 Oct 1997) |
| light-water reactor | <radiobiology> Class of fission reactors using ordinary light water as a coolant, rather than liquid metal or heavy water (water with deuterium instead of hydrogen). (09 Oct 1997) |
| light wire appliance | An orthodontic appliance utilizing small gauge labial wires with expansion and contraction loops formed into it and attached to bands fitted to individual teeth; sometimes called Begg light wire differential force technique. (05 Mar 2000) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |
| achievement test | A standardised test used to measure acquired learning, e.g., competence in a specific subject area such as reading or arithmetic, in contrast to an intelligence test which is a useful index of potential ability or learning. (05 Mar 2000) |
| acidified serum test | Lysis of the patient's red cells in acidified fresh serum, specific for paroxysmal nocturnal haemoglobinuria. Synonym: Ham's test. (05 Mar 2000) |
| acid loading test | <nephrology> This is a test used in the diagnosis of renal tubular acidosis. The patient takes ammonium chloride capsules for 3 days to acidify the blood (lower blood pH). A sample of the urine and the blood is then collected and the results are interpreted. (27 Sep 1997) |