| free water | Water in the body that can be removed by ultrafiltration and in which substances can be dissolved. (05 Mar 2000) |
|---|---|
| free water clearance | The amount of water excreted in the urine beyond that which would accompany the excreted solutes if the urine were isosmotic with plasma; it represents the loss of body water in excess of solute tending to raise body osmolality and making urine hyposmotic. Unlike other clearance's, it is calculated by subtracting the osmolal clearance from the actual volume of urine excreted per minute. A negative value for free water clearance represents the amount of water that the body has reclaimed from isosmotic tubule fluid to make the urine hyperosmotic and to lower body osmolality. (05 Mar 2000) |
| fresh water | 1. Water containing no significant amounts of salts, such as rivers and lakes. 2. Of, pertaining to, or living in, water not salt; as, fresh-water geological deposits; a fresh water fish; fresh water mussels. 3. Accustomed to sail on fresh water only; unskilled as a seaman; as, a fresh water sailor. 4. Unskilled; raw. Fresh water soldiers. Source: Websters Dictionary (01 Mar 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) |
| lime water | Calcium hydroxide solution; a saturated solution prepared by mixing 3 g of calcium hydroxide in a liter of purified cool water. Undissolved calcium hydroxide is allowed to precipitate and the solution is dispensed without agitation; lime water is a common ingredient in lotions and is used internally extensively in veterinary medicine. (05 Mar 2000) |
| littoral water | Shallow water, to 30 feet, near the shore of deep lakes. (09 Oct 1997) |
| 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) |
| acid perfusion test | <gastroenterology, investigation> A test used to diagnosis gastrooesophageal reflux disease. This investigation requires that the patient swallow 3 tiny tubes into the stomach. A mixture of hydrochloric acid (like stomach acid) and saline are alternatively injected into the tubes. The patient then reports any symptoms they may have. Some patients may vomit. (13 Nov 1997) |
| acid phosphatase test for semen | A screening test for semen by determining acid phosphatase content; because seminal fluid contains high concentrations of acid phosphatase, while other body fluids and extraneous foreign materials have very low concentrations, high values of acid phosphatase on vaginal aspirate or lavage, or on wash fluid from stains, render positive identification of semen, even if the male is aspermic. (05 Mar 2000) |
| acid reflux test | A test to detect gastroesophageal reflux by monitoring oesophageal pH by an electrode in the distal oesophagus either basally or after acid is instilled into the stomach. (05 Mar 2000) |