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Longman Dictionary of Contemporary English
a carbon/nitrogen/sulphur etc compound
▪ Use a copper compound to protect the trees from pests.
▪ The specimens were weighed immediately, frozen in liquid nitrogen, and stored at -80°C.
▪ The ceramics -- cables encased in a sheath of liquid nitrogen -- are being developed for power generation and other machinery applications.
▪ In addition, it would consume liquid nitrogen for cooling purposes at approximately £20 per trip.
▪ The tissue was then snap-frozen by immersion in liquid nitrogen before storage at -70°C for up to six months.
▪ At both operations, biopsies from the tumour and non-tumour liver tissue were collected and snap frozen in liquid nitrogen.
▪ After immersion in 40% glycerin solution at room temperature, they were placed on a copper stage and frozen with liquid nitrogen.
▪ This test was used to ensure a 100% death rate of cells frozen in liquid nitrogen.
▪ The specimens were frozen immediately in liquid nitrogen and subjected to autofluorescence microscopy.
▪ It is usually caused by the emission of particulates or nitrogen dioxide.
▪ The sulphur dioxide level in Belfast was 32 parts per billion while the nitrogen dioxide level was 48.
▪ The southern California air basin is the only area in the country that still fails to meet the nitrogen dioxide standard.
▪ The gas is cleaned prior to burning and the sulphur dioxide and nitrogen dioxide, thought to contribute to acid rain, removed.
▪ However, this statistic conceals that levels of nitrogen dioxide have changed little since 1983.
▪ Of those figures, Britain contributed 1.84 million tonnes of sulphur and an equal amount of nitrogen dioxide.
▪ Apart from general operating conditions, it has set emission limits for sulphur dioxide, nitrogen dioxide and carbon monoxide.
▪ What are the prospects for nitrogen fixation in plants?
▪ Around half of the nitrogen in the burnt biomass may be released as nitrogen gas.
▪ It was inflated with nitrogen gas within minutes and looked like a silver parachute.
▪ Four-fifths of the modern atmosphere consists of nitrogen gas.
▪ Bacteria then work on the nitrates converting them firstly to nitrous oxide and then to free nitrogen gas.
▪ The new standards cut emissions of carbon monoxide, nitrogen oxides, gaseous hydrocarbons and particulate matter.
▪ First, the nitrogen oxides are toxic to animals.
▪ To avoid further damage to sensitive ecosystems, sulphur and nitrogen oxide emissions must be cut by 90 percent.
▪ These same nitrogen oxides, in high but apparently plausible concentrations, will defoliate plants.
▪ Nitrogen oxide Forty percent of nitrogen oxide emissions in Britain come from vehicles.
▪ Global warming occurs when carbon dioxide and some other gases, such as methane and nitrogen oxides, accumulate in the atmosphere.
▪ The situation is exacerbated by unusually low levels of nitrogen oxides, which inhibit ozone destruction.
▪ Large explosions heat vast masses of the atmosphere to such high temperatures that nitrogen is partially burned to make toxic nitrogen oxides.
▪ The specimens were weighed immediately, frozen in liquid nitrogen, and stored at -80°C.
▪ This test was used to ensure a 100% death rate of cells frozen in liquid nitrogen.
▪ The specimens were frozen immediately in liquid nitrogen and subjected to autofluorescence microscopy.
▪ The nitrogenous materials which have been oxidized aerobically to nitrate are then reduced anaerobically to nitrogen.
▪ Aerozine 50 was used as the fuel, with nitrogen tetroxide as the oxidizer.
▪ Both countries would also limit nitrogen oxide emissions through stricter controls on motor vehicles.
▪ But close examination showed that species intolerant of acid conditions or high nitrogen levels were not reappearing.
▪ Global warming occurs when carbon dioxide and some other gases, such as methane and nitrogen oxides, accumulate in the atmosphere.
▪ Large explosions heat vast masses of the atmosphere to such high temperatures that nitrogen is partially burned to make toxic nitrogen oxides.
▪ On reflection, I think we made the nitrogen bands rather too wide.
▪ Peas and beans put nitrogen into the soil.
▪ The very low abundances of volatiles and especially the low nitrogen abundance all pose special problems.
The Collaborative International Dictionary

Nitrogen \Ni`tro*gen\ (n[imac]"tr[-o]*j[e^]n), n. [L. nitrum natron + -gen: cf. F. nitrog[`e]ne. See Niter.] (Chem.) A colorless nonmetallic element of atomic number 7, tasteless and odorless, comprising four fifths of the atmosphere by volume in the form of molecular nitrogen ( N2). It is chemically very inert in the free state, and as such is incapable of supporting life (hence the name azote still used by French chemists); but it forms many important compounds, such as ammonia, nitric acid, the cyanides, etc, and is a constituent of all organized living tissues, animal or vegetable. Symbol N. Atomic weight 14.007. It was formerly regarded as a permanent noncondensible gas, but was liquefied in 1877 by Cailletet of Paris, and Pictet of Geneva, and boils at -195.8 [deg] C at atmospheric pressure. Liquid nitrogen is used as a refrigerant to store delicate materials, such as bacteria, cells, and other biological materials.

Douglas Harper's Etymology Dictionary

1794, from French nitrogène, coined 1790 by French chemist Jean Antoine Chaptal (1756-1832), from comb. form of Greek nitron "sodium carbonate" (see nitro-) + French gène "producing," from Greek -gen "giving birth to" (see -gen). The gas was identified in part by analysis of nitre. Earlier name (1772) was mephitic air, and Lavoisier called it azote (see azo-).


n. 1 (context uncountable English) A chemical element (''symbol'' N) with an atomic number of 7 and atomic weight of 14.0067. 2 (context uncountable English) Molecular nitrogen (N2), a colorless, odorless gas at room temperature. 3 (context countable English) A specific nitrogen within a chemical formula, or a specific isotope of nitrogen


n. a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues [syn: N, atomic number 7]


Nitrogen is a chemical element with symbol N and atomic number 7. It is the lightest pnictogen, and at room temperature it is a transparent, odorless diatomic gas. Nitrogen is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System. On Earth, the element forms about 78% of Earth's atmosphere and is the most abundant uncombined element. The element nitrogen was discovered as a separable component of air by Scottish physician Daniel Rutherford in 1772.

Many industrially important compounds, such as ammonia, nitric acid, organic nitrates ( propellants and explosives), and cyanides, contain nitrogen. The extremely strong triple bond in elemental nitrogen (N≡N) dominates nitrogen chemistry, causing difficulty for both organisms and industry in converting the N into useful compounds, but at the same time causing release of large amounts of often useful energy when the compounds burn, explode, or decay back into nitrogen gas. Synthetically produced ammonia and nitrates are key industrial fertilizers, and fertilizer nitrates are key pollutants in the eutrophication of water systems.

Apart from its use in fertilizers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar fabric and cyanoacrylate "super" glue. Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many drugs are mimics or prodrugs of natural nitrogen-containing signal molecules: for example, the organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolizing into nitric oxide. Plant alkaloids (often defense chemicals) contain nitrogen by definition, and many notable nitrogen-containing drugs, such as caffeine and morphine, are either alkaloids or synthetic mimics that act (as many plant alkaloids do) on receptors of animal neurotransmitters (for example, synthetic amphetamines).

Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids ( DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% by mass of nitrogen, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere.

Usage examples of "nitrogen".

Animal matter enters into combination with oxygen in precisely the same way as vegetable matter, but as, in addition to carbon and hydrogen, it contains nitrogen, the products of the eremacausis are more numerous, being carbon and nitrate of ammonia, carburetted and sulphuretted hydrogen, and water, and these ammoniacal salts greatly favor the growth of fungi.

Measurements of blood sugar, serum amylase, serum acetone, bilirubin, and blood urea nitrogen were normal.

He knew that liquid nitrogen, a waste product of certain industrial processes, is cheaper than natural gas.

The nitrogen of this and other cruciferous plants serves to make them emit offensive stinks when they lie out of doors and rot.

Modern chemists, however, made it from nitrogen of the very air we breathe, and in Germany it was made during the war from ammonia and calcium cyanamide, both of which may be obtained from the air.

Oatmeal comes the nearest to wheat in the amount of nitrogen or protein, but the digestible part of this is much smaller than in wheat, and the indigestible portion is decidedly irritating to the bowels, so that if used in excess of about one-fifth of our total starch-food required, it is likely to upset the digestion.

One possible explanation: Freshly fallen snows of nitrogen, methane, and other hydrocarbons are irradiated by solar ultraviolet light and by electrons trapped in the magnetic field of Neptune, through which Triton plows.

To guard against loss of nitrogen by leaching, therefore, we should aim to keep rich land occupied by some crop, during the winter and early spring, and the earlier the crop is sown in the autumn or late summer, the better, so that the roots will the more completely fill the ground and take up all the available nitrogen within their reach.

They thought nothing of whipping out a sledgehammer and beating a porthole from the side of a ship, even as their heavy breath hastened nitrogen narcosis, the potentially deadly buildup of that otherwise benign gas in their brains.

There is more cerium on Earth than copper, more neodymium and lanthanum than cobalt or nitrogen.

Nitrogen, Nb for Nobelium, Nd for Neodymium, Ne for Neon, Ni for Nickel, No for Niobrium, Np for Neptunium.

Closer still, the nitrogen had the appearance of a huge flower, petals curling beneath the nimbostratus canopy as gases hit the cold air and sheared down again.

Ordinarily, monoamine oxidase brings about the oxidation of serotonin into a normal metabolite, one in which the nitrogen atoms have been removed.

They are sealed between uses and all the oxygen-nitrogen is pumped out to keep the oxy from leaking out and contaminating the nitrogen atmosphere in the stacks.

A pound of nitrogen in the leached guano is not as available or as valuable as a pound of nitrogen in the unleached guano.