| free radical | A chemically active atom or molecular fragment containing a chemical charge due to an excess or deficient number of electrons. Radicals seek to receive or release electrons in order to achieve a more stable configuration, a process that can damage the large molecules within cells. See: Oxidation. (09 Oct 1997) |
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| free radical reductase | <enzyme> Catalyses conversion of carbon-centreed lipid radicals into an inactive species by utilizing vitamin e at one end and glutathione at the other Registry number: EC 1.8.4.- (26 Jun 1999) |
| free radicals | Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated. (12 Dec 1998) |
| free radical scavengers | Substances that influence the course of a chemical reaction by ready combination with free radicals. Among other effects, this combining activity protects pancreatic islets against damage by cytokines and prevents myocardial and pulmonary perfusion injuries. (12 Dec 1998) |
| free-swimming | <zoology> Swimming in the open sea; said of certain marine animals. Source: Websters Dictionary (01 Mar 1998) |
| free tenia | See: teniae coli. Synonym: tenia libera. (05 Mar 2000) |
| free thyroxine index | An arbitrary value obtained by multiplying the triiodothyronine uptake by the serum thyroxine concentration; it largely corrects for variations in thyroid-bound globulin concentration by providing a clinically valid estimate of the physiologically active free thyroxine; direct assay or laboratory measurement of free serum thyroxine yields a more accurate value. (05 Mar 2000) |
| free villus | A chorionic villus that is not attached to the decidua basalis, but is "free" in the maternal blood of the intervillous spaces. Synonym: floating villus. (05 Mar 2000) |
| free wave | <radiobiology> A wave (for example, electromagnetic) traveling in a homogeneous infinite medium (no boundary conditions). (09 Oct 1997) |
| free will | 1. A will free from improper coercion or restraint. "To come thus was I not constrained, but did On my free will." (Shak) 2. The power asserted of moral beings of willing or choosing without the restraints of physical or absolute necessity. Source: Websters Dictionary (01 Mar 1998) |
| alkaline water | A water that contains appreciable amounts of the bicarbonates of calcium, lithium, potassium, or sodium. (05 Mar 2000) |
| aromatic water | 1. To wet or supply with water; to moisten; to overflow with water; to irrigate; as, to water land; to water flowers. "With tears watering the ground." (Milton) "Men whose lives gilded on like rivers that water the woodlands." (Longfellow) 2. To supply with water for drink; to cause or allow to drink; as, to water cattle and horses. 3. To wet and calender, as cloth, so as to impart to it a lustrous appearance in wavy lines; to diversify with wavelike lines; as, to water silk. Cf. Water. 4. To add water to (anything), thereby extending the quantity or bulk while reducing the strength or quality; to extend; to dilute; to weaken. To water stock, to increase the capital stock of a company by issuing new stock, thus diminishing the value of the individual shares. Cf. Water. Origin: AS. Waeterian, gewaeterian. 1. The fluid which descends from the clouds in rain, and which forms rivers, lakes, seas, etc. "We will drink water." ."Powers of fire, air, water, and earth." . Pure water consists of hydrogen and oxygen, H2O, and is a colourless, odorless, tasteless, transparent liquid, which is very slightly compressible. at its maximum density, 39 deg Fahr. Or 4 deg C, it is the standard for specific gravities, one cubic centimeter weighing one gram. It freezes at 32 deg Fahr. Or 0 deg C. And boils at 212 deg Fahr. Or 100 deg C. (see Ice, Steam). It is the most important natural solvent, and is frequently impregnated with foreign matter which is mostly removed by distillation; hence, rain water is nearly pure. It is an important ingredient in the tissue of animals and plants, the human body containing about two thirds its weight of water. 2. A body of water, standing or flowing; a lake, river, or other collection of water. "Remembering he had passed over a small water a poor scholar when first coming to the university, he kneeled." (Fuller) 3. Any liquid secretion, humor, or the like, resembling water; especially, the urine. 4. <pharmacology> A solution in water of a gaseous or readily volatile substance; as, ammonia water. 5. The limpidity and luster of a precious stone, especially a diamond; as, a diamond of the first water, that is, perfectly pure and transparent. Hence, of the first water, that is, of the first excellence. 6. A wavy, lustrous pattern or decoration such as is imparted to linen, silk, metals, etc. See Water, 3, Damask, and Damaskeen. 7. An addition to the shares representing the capital of a stock company so that the aggregate par value of the shares is increased while their value for investment is diminished, or "diluted." Water is often used adjectively and in the formation of many self-explaining compounds; as, water drainage; water gauge, or water-gauge; waterfowl, water-fowl, or water fowl; water-beaten; water-borne, water-circled, water-girdled, water-rocked, etc. Hard water. See Hard. Inch of water, a unit of measure of quantity of water, being the quantity which will flow through an orifice one inch square, or a circular orifice one inch in diameter, in a vertical surface, under a stated constant head; also called miner's inch, and water inch. The shape of the orifice and the head vary in different localities. In the Western United States, for hydraulic mining, the standard aperture is square and the head from 4 to 9 inches above its center. In Europe, for experimental hydraulics, the orifice is usually round and the head from 1/12 of an inch to 1 inch above its top. Mineral water, waters which are so impregnated with foreign ingredients, such as gaseous, sulphureous, and saline substances, as to give them medicinal properties, or a particular flavor or temperature. Soft water, water not impregnated with lime or mineral salts. To hold water. See Hold, To keep one's head above water, to keep afloat; fig, to avoid failure or sinking in the struggles of life. To make water. To pass urine. <medicine> Hydrothorax. Other phrases, in which water occurs as the first element, will be found in alphabetical order in the Vocabulary. Origin: AS. Waeter; akin to OS. Watar, OFries. Wetir, weter, LG. & D. Water, G. Wasser, OHG. Wazzar, Icel. Vatn, Sw. Vatten, Dan. Vand, Goth. Wat, O. Slav. & Russ. Voda, Gr, Skr. Udan water, ud to wet, and perhaps to L. Unda wave. Cf. Dropsy, Hydra, Otter, Wet, Whisky. Source: Websters Dictionary (01 Mar 1998) |
| baryta water | A saturated aqueous solution of barium hydroxide; used as an alkaline reagent. (05 Mar 2000) |
| bitter water | A natural mineral water containing Epsom salt. (05 Mar 2000) |
| black water | azoturia of horses |