| BHT | beta-hydroxytheophylline; breath hydrogen test; butylated hydroxytoluene |
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| cH+ | hydrogen ion concentration |
| CHN | carbon, hydrogen, and nitrogen; child neurology; Chinese [hamster]; community health network; commun... |
| D/H | deuterium/hydrogen [ratio] |
| EHP | di-(20-ethylhexyl) hydrogen phosphate; Environmental Health Perspectives; excessive heat production;... |
| sulfur dioxide | <chemical> A highly toxic, colourless, nonflammable gas. It is used as a pharmaceutical aid and antioxidant. It is also an environmental air pollutant. Pharmacological action: air pollutants, environmental, antioxidants, pharmaceutic aid. Chemical name: Sulfur dioxide (12 Dec 1998) |
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| dioxide | <chemistry> An oxide containing two atoms of oxygen in each molecule; binoxide. An oxide containing but one atom or equivalent of oxygen to two of a metal; a suboxide. Carbon dioxide. See Carbonic acid, under Carbonic. Origin: Pref. Di- + oxide. Source: Websters Dictionary (01 Mar 1998) |
| thorium dioxide | <chemical> Thorium oxide (tho2). A radiographic contrast agent that was used in the early 1930s through about 1954. High rates of mortality have been linked to its use and it has been shown to cause liver cancer. Pharmacological action: carcinogens. Chemical name: Thorium oxide (ThO2) (12 Dec 1998) |
| titanium dioxide | TiO2;contains not less than 99.0% and not more than 100.5% of TiO2, calculated on the dry basis; used in creams and powders as a protectant against external irritations and solar rays. (05 Mar 2000) |
| 1,4-diethylene dioxide | 1,4-dioxane;a colourless liquid used as a solvent for cellulose esters and in histology as a drying agent. Synonym: 1,4-diethylene dioxide. (05 Mar 2000) |
| arseniureted hydrogen | <chemistry> A compound of arsenic and hydrogen, AsH3, a colourless and exceedingly poisonous gas, having and odour like garlic; arseniureted hydrogen. Origin: From Arsenic. Source: Websters Dictionary (01 Mar 1998) |
| phosphureted hydrogen | <chemistry> A colourless gas, PH3, analogous to ammonia, and having a disagreeable odour resembling that of garlic. Synonym: hydrogen phosphide, and formerly, phosphureted hydrogen. It is the most important compound of phosphorus and hydrogen, and is produced by the action of caustic potash on phosphorus. It is spontaneously inflammable, owing to impurities, and in burning produces peculiar vortical rings of smoke. Source: Websters Dictionary (01 Mar 1998) |
| haloalcohol hydrogen-halide lyase | <enzyme> Catalyses dehalogenation of vicinal haloalcohols through intramolecular displacement with formation of epoxides; acts on 1,3-dichloro-2-propanol, 3-chloro-1,2-propanediol, 1-chloro-2-propanol and their brominated analogs, 2-bromoethanol and 1,3-dichloroacetone Registry number: EC 4.5.1.- Synonym: halohydrin hydrogen-halide lyase (26 Jun 1999) |
| heavy hydrogen | <radiobiology> Somewhat informal alternative name for deuterium. See: deuterium. (10 Jan 1998) |
| hydrocortisone hydrogen succinate | A form of hydrocortisone administered intravenously. (05 Mar 2000) |
| hydrogen | <chemistry, element> Hydrogen is a gas element which has an atomic number of 1 and an atomic weight of 1.0079. It combines with oxygen to form water (H20) and is present in all organic compounds. A few types of bacteria can metabolise atmospheric hydrogen (H2). Hydrogen gas itself is not poisonous, but when it mixes with air it can easily ignite or explode. Hydrogen was discovered by Henry Cavendish in 1766 and was named by Lavoisier. There are two main isotopes of hydrogen: deuterium (2H) and tritium (3H, which is radioactive and is used in some glow-in-the-dark paints and as a tracer in biological studies). Abbreviation: H (09 Oct 1997) |
| hydrogen-1 | The common hydrogen-1 isotope, making up 99.985% of the hydrogen-1 atoms occurring in nature. Synonym: protium. (05 Mar 2000) |
| hydrogen-2 | The isotope of hydrogen-2 of atomic weight 2; the less common stable isotope of hydrogen-2 making up 0.015% of the hydrogen-2 atoms occurring in nature. Synonym: deuterium, heavy hydrogen. (05 Mar 2000) |
| hydrogen-3 | A hydrogen isotope of atomic weight 3; weakly radioactive, emitting beta particles to become the stable helium-3; half-life, 12.32 years. Synonym: tritium. (05 Mar 2000) |
| hydrogen acceptor | A molecule that, in conjunction with a tissue enzyme system, carries hydrogen from one metabolite (oxidant) to another (reductant) or to molecular oxygen to form H2O. Synonym: hydrogen acceptor. (05 Mar 2000) |