| nitrogen | <chemistry> A colourless nonmetallic element, tasteless and odorless, comprising four fifths of the atmosphere by volume. 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, as ammonia, nitric acid, the cyanides, etc, and is a constituent of all organised living tissues, animal or vegetable. Symbol N. Atomic weight 14. It was formerly regarded as a permanent noncondensible gas, but was liquefied in 1877 by Cailletet of Paris, and Pictet of Geneva. Origin: L. Nitrum natron + -gen: cf. F. Nitrogene. See Niter. Source: Websters Dictionary (01 Mar 1998) |
|---|---|
| nitrogen balance | The difference between the total nitrogen intake by an organism and its total nitrogen loss. A normal, healthy adult has a zero nitrogen balance, Nin Nout (i.e., a positive nitrogen balance. (05 Mar 2000) |
| nitrogen compounds | Inorganic compounds that contain nitrogen as an integral part of the molecule. (12 Dec 1998) |
| nitrogen cycle | <biochemistry> The global cycle of moving various forms of nitrogen through the air, water, soil, plants, animals of the planet. See: nitrogen fixation. (09 Oct 1997) |
| nitrogen dioxide | <chemical> Nitrogen oxide (no2). A highly poisonous gas. Exposure produces inflammation of lungs that may only cause slight pain or pass unnoticed, but resulting oedema several days later may cause death. It is a major atmospheric pollutant that is able to absorb uv light that does not reach the earth's surface. Pharmacological action: oxidants, photochemical, poisons. Chemical name: Nitrogen oxide (NO2) (12 Dec 1998) |
| nitrogen distribution | Determination of the distribution of nitrogen in the urine among the various constituents. Synonym: nitrogen distribution. (05 Mar 2000) |
| nitrogen equivalent | The nitrogen content of protein; used in calculating the protein breakdown in the body from the nitrogen excreted in the urine, 1 g of nitrogen considered as having originated in 6.25 g of protein catabolised. (05 Mar 2000) |
| nitrogen fixation | <biochemistry> The incorporation of atmospheric nitrogen into ammonia by various bacteria, catalysed by nitrogenase. This is an essential stage in the nitrogen cycle and is the ultimate source of all nitrogen in living organisms. In the sea, the main nitrogen fixers are Cyanobacteria. There are several free living bacteria in soil that fix nitrogen including species of Azotobacter, Clostridium and Klebsiella. Rhizobium only fixes nitrogen when in symbiotic association, in root nodules, with leguminous plants. The oxygen sensitive nitrogenase is protected by plant produced leghaemoglobin and the plant obtains fixed nitrogen from the bacteria. See: Frankia. (18 Nov 1997) |
| nitrogen group | Five trivalent or quinquivalent elements whose hydrogen compounds are basic and whose oxyacids vary from monobasic to tetrabasic: nitrogen, phosphorus, arsenic, antimony, and bismuth. (05 Mar 2000) |
| nitrogen isotopes | Stable nitrogen atoms that have the same atomic number as the element nitrogen, but differ in atomic weight. N-15 is a stable nitrogen isotope. (12 Dec 1998) |
| nitrogen lag | The length of time after the ingestion of a given protein before the amount of nitrogen equal to that in the protein has been excreted in the urine. (05 Mar 2000) |
| nitrogen monoxide | <chemical> Nitrogen oxide (n2o). A colourless, odourless gas that is used as an anaesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream. Pharmacological action: aerosol propellants, analgesics, non-narcotic, anaesthetics, inhalation. Chemical name: Nitrogen oxide (N2O) (12 Dec 1998) |
| nitrogen mustard compounds | <chemical> A group of alkylating agents derived from mustard gas, with the sulfur replaced by nitrogen. They were formerly used as toxicants and vesicants, but now function as antineoplastic agent. These compounds are also powerful mutagens, teratogens, immunosuppressants, and carcinogens. Pharmacological action: antineoplastic agent, alkylating, carcinogens, mutagens, teratogens. (12 Dec 1998) |
| nitrogen mustards | <pharmacology> A series of tertiary amine compounds having vesicant properties similar to those of mustard gas. They have the general formula RN(CH2CH2Cl)2. They can alkylate compounds such as DNA and are used as the basis of cytostatic drugs for cancer chemotherapy. (18 Nov 1997) |
| nitrogen narcosis | Narcosis produced by nitrogenous materials such as occurs in certain forms of uraemia and hepatic coma, the stuporous condition characterised by disorientation and by loss of judgment and skill, attributed to an increased partial pressure of nitrogen in the inspired air of deepsea divers during underwater operations. Commonly referred to as "rapture of the deep." (05 Mar 2000) |
Synonyms : N(G)-Nitroarginine, N(omega)-Nitroarginine, NO2Arg, omega-Nitroarginine, N omega Nitro L Arginine, NG Nitro L Arginine, NG Nitroarginine, omega Nitroarginine, omega-Nitro-L-Arginine, N
Synonyms :
Synonyms :
Synonyms :
Synonyms : Nitro-BT, Nitrotetrazolium Blue, Tetrazolium Nitroblue, Blue, Nitrotetrazolium, Nitroblue, Tetrazolium, Tetrazolium, Nitroblue
| nitrogen fixation |
the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria
출처: wordnet.princeton.edu/perl/webwn
|
|---|---|
| nitrogen mustard |
a toxic compound resembling mustard gas in structure; important in cancer treatment
출처: wordnet.princeton.edu/perl/webwn
|
| nitrogen narcosis |
confused or stuporous state caused by high levels of dissolved nitrogen in the blood; "deep-sea divers can suffer nitrogen narcosis from breathing air under high pressure"
출처: wordnet.princeton.edu/perl/webwn
|
| nitrogenase |
an enzyme of nitrogen-fixing microorganisms that catalyzes the conversion of nitrogen to ammonia
출처: wordnet.princeton.edu/perl/webwn
|
| nitrogenous |
of or relating to or containing nitrogen
출처: wordnet.princeton.edu/perl/webwn
|
| nit | a heavy yellow poisonous oily explosive liquid obtained by nitrating glycerol |
|---|---|
| nit | trade names for nitroglycerin used as a coronary vasodilator in the treatment of angina pectoris |
| nit | a heavy yellow poisonous oily explosive liquid obtained by nitrating glycerol |
| nit | of or containing nitrogen |
| nit | an unstable inorganic acid known only in solution and as nitrite salts |
| nit | soil bacteria that oxidize ammonia to nitrites |
| nit | any of the nitrobacteria that oxidize ammonia into nitrites |
| nit | inhalation anesthetic used as an anesthetic in dentistry and surgery |
| nit | any of several Old World tropical trees of the genus Parkia having heads of red or yellow flowers followed by pods usually containing edible seeds and pulp |
| nit | the choicest or most essential or most vital part of some idea or experience |
| nit | annual wiry-stemmed North American weed with minute scalelike leaves and small yellow flowers |
| nit | (informal) a stupid incompetent person |