| fluoride | <chemical> The fluoride ion. Low levels of fluoride in drinking water markedly decrease the incidence of dental caries, probably because bacterial metabolism is much more sensitive to low fluoride levels. (18 Nov 1997) |
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| fluoride number | The percent inhibition of pseudocholinesterase produced by fluorides; used to differentiate normal from atypical pseudocholinesterases. See: dibucaine number. (05 Mar 2000) |
| fluoride poisoning | Gen or unspecified fluoride; prefer /pois with specific fluoride term (12 Dec 1998) |
| fluorides | Inorganic salts of hydrofluoric acid, hf, in which the fluorine atom is in the -1 oxidation state. (12 Dec 1998) |
| fluorides, topical | Fluorides, usually as pastes or gels, used for topical application to reduce the incidence of dental caries. (12 Dec 1998) |
| fluoridization | Therapeutic use of fluorides to reduce the incidence of dental decay; sometimes used to refer to the topical application of fluoride agents to the teeth. (05 Mar 2000) |
| fluorimetry | The measurement of the amount of fluorescence. (09 Oct 1997) |
| fluorinated hydrocarbon | A molecule which is almost entirely carbon and hydrogen, but has had at least one fluorine atom introduced to it that has replaced one of the hydrogen atoms. (09 Oct 1997) |
| fluorine | <chemistry, element> A non-metallic, gaseous element, strongly acid or negative, or associated with chlorine, bromine, and iodine, in the halogen group of which it is the first member. It always occurs combined, is very active chemically, and possesses such an avidity for most elements, and silicon especially, that it can neither be prepared nor kept in glass vessels. If set free it immediately attacks the containing material, so that it was not isolated until 1886. It is a pungent, corrosive, colourless gas. Fluorine unites with hydrogen to form hydrofluoric acid, which is the agent employed in etching glass. It occurs naturally, principally combined as calcium fluoride in fluorite, and as a double fluoride of aluminium and sodium in cryolite. Atomic weight: 19 Abbreviation: F Origin: NL. Fluorina: cf. G. Fluorin, F. Fluorine. So called from its occurrence in the mineral fluorite. (30 Mar 1998) |
| fluorine compounds | Inorganic compounds that contain fluorine as an integral part of the molecule. (12 Dec 1998) |
| fluorine radioisotopes | Unstable isotopes of fluorine that decay or disintegrate emitting radiation. F atoms with atomic weights 17, 18, and 20-22 are radioactive fluorine isotopes. (12 Dec 1998) |
| fluorite | <chemical> Calcium fluoride, a mineral of many different colours, white, yellow, purple, green, red, etc, often very beautiful, crystallizing commonly in cubes with perfect octahedral cleavage; also massive. It is used as a flux. Some varieties are used for ornamental vessels. Also called fluor spar, or simply fluor. Source: Websters Dictionary (01 Mar 1998) |
| fluorite objective | Microscope objective corrected for spherical and chromatic aberration at two wavelengths. Better than an ordinary objective corrected at one wavelength but inferior to (and much cheaper than) a planapochromatic objective. (18 Nov 1997) |
| fluoro- | See: fluor-. (05 Mar 2000) |
| fluoro-2,4-dinitrobenzene | A reagent used to combine with the free NH2 group of the NH2-terminal amino acid residue in a peptide, thus marking this residue; the combined forms are known as DNP-proteins, Dnp-aminoacyl, etc., the fluorine having been replaced to leave a dinitrophenyl residue (DNP, Dnp, or N2Ph-) attached to the NH2 group. Synonym: Sanger's reagent. Acronym: FDNB (05 Mar 2000) |