| nitre | 1. <chemistry> A white crystalline semitransparent salt; potassium nitrate; saltpeter. See Saltpeter. 2. <chemistry> Native sodium carbonate; natron. "For though thou wash thee with niter, and take thee much soap, yet thine iniquity is marked before me." (Jer. Ii. 22) Cubic niter, a deliquescent salt, sodium nitrate, found as a native incrustation, like niter, in Peru and Chili, whence it is known also as Chili saltpeter. <botany> Niter bush, a genus (Nitraria) of thorny shrubs bearing edible berries, and growing in the saline plains of Asia and Northern Africa. Origin: F. Nitre, L. Nitrum native soda, natron, Gr.; cf. Ar. Nitn, natrn natron. Cf. Natron. <chemistry> See Niter. Source: Websters Dictionary (01 Mar 1998) |
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| nitrendipine | <chemical> Ethyl methyl 2,4-dihydro-2,6-dimethyl-4- (3-nitrophenyl)-3,5-pyridinedicarboxylate. A calcium channel blocker with marked vasodilator action. It is an effective antihypertensive agent and differs from other calcium channel blockers in that it does not reduce glomerular filtration rate and is mildly natriuretic, rather than sodium retentive. Pharmacological action: antihypertensive agents, calcium channel blockers, vasodilator agents. Chemical name: 3,5-Pyridinedicarboxylic acid, 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-, ethyl methyl ester (12 Dec 1998) |
| nitric | <chemistry> Of, pertaining to, or containing, nitrogen; specifically, designating any one of those compounds in which, as contrasted with nitrous compounds, the element has a higher valence; as, nitric oxide; nitric acid. Nitric acid, a colourless or yellowish liquid obtained by distilling a nitrate with sulphuric acid. It is powerfully corrosive, being a strong acid, and in decomposition a strong oxidizer. Nitric anhydride, a white crystalline oxide of nitrogen (N2O5), called nitric pentoxide, and regarded as the anhydride of nitric acid. Nitric oxide, a colourless poisous gas (NO) obtained by treating nitric acid with copper. On contact with the air or with oxygen, it becomes reddish brown from the formation of nitric dioxide or peroxide. Origin: Cf. F. Nitrique. See Niter. Source: Websters Dictionary (01 Mar 1998) |
| nitric acid | <chemical> Nitric acid (hno3). A colourless liquid that is used in the manufacture of inorganic and organic nitrates and nitro compounds for fertilisers, dye intermediates, explosives, and many different organic chemicals. Continued exposure to vapor may cause chronic bronchitis; chemical pneumonitis may occur. Chemical name: Nitric acid (12 Dec 1998) |
| nitric acid reductase | <enzyme> Found in pseudomonas stutzerie; transforms nitric oxide to nitrous oxide in an ascorbate-phenazine methosulfate-dependent reaction; not EC 1.7.99.2 Registry number: EC 1.7.99.- (26 Jun 1999) |
| nitric oxide | <biochemistry> This compound is produced from L arginine by the enzyme nitric oxide synthase. Acts as a potent vasorelaxant via elevation of intracellular cGMP in vascular smooth muscle. Synthesis of nitric oxide is not confined to endothelium, isoforms of nitric oxide synthase are also found in brain, neutrophils and platelets. Synonym: endothelium derived relaxation factor. Acronym: NO (29 Dec 1997) |
| nitric oxide synthase | <enzyme> An enzyme that catalyses the conversion of l-arginine, NADPH, and oxygen to citrulline, nitric oxide, and NADP+. The enzyme found in brain, but not that induced in lung or liver by endotoxin, requires calcium.There are two isoforms, one constitutive and one activated by calmodulin. Chemical name: L-Arginine,NADPH:oxygen oxidoreductase (nitric-oxide-forming) Registry number: EC 1.14.13.39 Acronym: NOS (12 Dec 1998) |
| nitric-oxide reductase | <enzyme> Prior to 1992 was classified as EC 1.7.99.2; a cytochrome bc complex; genbank af002217 (norb protein) and af002661 (norz protein) are from alcaligenes eutrophus Registry number: EC 1.7.99.7 Synonym: nitric oxide reductase, norb gene product, norz gene product (26 Jun 1999) |
| nitridation | Formation of nitrides; formation of nitrogen compounds through the action of ammonia (analogous to oxidation). (05 Mar 2000) |
| nitride | <chemistry> A binary compound of nitrogen with a more metallic element or radical; as, boric nitride. Origin: fromNitrogen. Source: Websters Dictionary (01 Mar 1998) |
| nitrification | 1. <chemistry> The act, process, or result of combining with nitrogen or some of its compounds. The act or process of oxidizing nitrogen or its compounds so as to form nitrous or nitric acid. 2. A process of oxidation, in which nitrogenous vegetable and animal matter in the presence of air, moisture, and some basic substances, as lime or alkali carbonate, is converted into nitrates. The process is going on at all times in porous soils and in water contaminated with nitrogenous matter, and is supposed to be due to the presence of an organised ferment or ferments, called nitrification ferments. In former times the process was extensively made use of in the production of saltpeter. Origin: Cf. F. Nitrification. See Nitrify. Source: Websters Dictionary (01 Mar 1998) |
| nitrifier | <chemistry> An agent employed in nitrification. Source: Websters Dictionary (01 Mar 1998) |
| nitrify | <chemistry> To combine or impregnate with nitrogen; to convert, by oxidation, into nitrous or nitric acid; to subject to, or produce by, nitrification. Origin: Niter + -fy: cf. F. Nitrifer. See Niter. Source: Websters Dictionary (01 Mar 1998) |
| nitrile | <chemistry> Any one of a series of cyanogen compounds; particularly, one of those cyanides of alcohol radicals which, by boiling with acids or alkalies, produce a carboxyl acid, with the elimination of the nitrogen as ammonia. The nitriles are named with reference to the acids produced by their decomposition, thus, hydrocyanic acid is formic nitrile, and methyl cyanide is acetic nitrile. See: Nitro-. Source: Websters Dictionary (01 Mar 1998) |
| nitrile hydratase | <enzyme> Converts nitriles to the corresponding amides; has been sequenced; genbank u89363 Registry number: EC 4.2.1.- (26 Jun 1999) |