nitrogen

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nitrogen

 (N) [ni´tro-jen]
a chemical element, atomic number 7, atomic weight 14.007. (See Appendix 6.) It is a gas constituting about four-fifths of common air; chemically it is almost inert. It is not poisonous but is fatal if breathed alone because of oxygen deprivation. It is soluble in the blood and body fluids, and can cause serious symptoms when released as bubbles of gas by rapid decompression (see bends). Nitrogen occurs in proteins and amino acids and is thus present in all living cells.
nitrogen 13 a radioactive isotope of nitrogen having a half-life of 9.97 minutes and decaying by positron emission; it is used as a tracer in positron emission tomography.
nitrogen balance the state of the body in regard to the rate of protein intake and protein utilization. When protein is metabolized, about 90 per cent of its nitrogen is excreted in the urine in the form of urea, uric acid, creatinine, and other nitrogen end-products. The remaining 10 per cent of the nitrogen is eliminated in the feces. A negative nitrogen balance occurs when more protein is used by the body than is taken in. A positive nitrogen balance implies a net gain of protein in the body. Negative nitrogen balance can be caused by such factors as malnutrition, debilitating diseases, blood loss, and glucocorticoids. A positive balance can be caused by exercise, growth hormone, and testosterone.
liquid nitrogen nitrogen in liquid form, i.e., below −195.79°C; used as a coolant, such as in thermographic equipment.
nitrogen mustards a group of toxic, blistering alkylating agents that are cell cycle phase nonspecific; it includes nitrogen mustard itself (mechlorethamine hydrochloride), chlorambucil, cyclophosphamide, ifosfamide, and melphalan. Some have been used as antineoplastic agents in certain forms of cancer; they do not cure these conditions, but ease their effects by destroying mitotic cells (those newly formed by division), thereby affecting malignant tissue in its early stage of development, and leaving normal tissue unaffected. They are especially useful in treatment of leukemia, in which they reduce the leukocyte count, and in cases in which the malignant disease is widespread throughout the body and therefore cannot be effectively treated locally by surgery or radiotherapy. In cases of lung cancer, mechlorethamine hydrochloride is usually injected directly into the lungs via the pulmonary circulation. Side effects, which tend to limit the usefulness of these drugs, include nausea, vomiting, and a decrease in bone marrow production.
nonprotein nitrogen (NPN) the nitrogenous constituents of the blood exclusive of the protein bodies, consisting of the nitrogen of urea, uric acid, creatine, creatinine, amino acids, polypeptides, and an undetermined part known as rest nitrogen. Measurement of this is used as a test of renal function, but has been largely replaced by measurement of specific substances, such as urea and creatinine.
nitrogen washout test a test for vital capacity of lungs; with the patient inhaling pure oxygen, the volume of exhaled nitrogen is obtained for each breath until it falls below 1 per cent of the gas being exhaled (usually about seven minutes' time); the total volume of nitrogen that has been exhaled at this point is assumed to be 0.8 of the vital capacity.
nitrogen washout test, single breath the patient inhales a vital capacity's volume of pure oxygen and then slowly exhales. The nitrogen content of the exhalation is measured over the entire breath and a curve is generated; different parts of the curve represent nitrogen concentrations of gas in different components of the total lung capacity, and can be analyzed for irregularities. Called also single breath test.

ni·tro·gen (N),

(nī'trō-jen),
1. A gaseous element, atomic no. 7, atomic wt. 14.00674; N2 forms about 78.084% by volume of the dry atmosphere.
2. The molecular form of nitrogen, N2.
3. Pharmaceutical grade N2, containing not less than 99.0% by volume of N2; used as a diluent for medicinal gases, and for air replacement in pharmaceutical preparations.
[L. nitrum, niter, + -gen, to produce]

nitrogen

/ni·tro·gen/ (N) (ni´tro-jen) a chemical element, at. no. 7. It forms about 78 per cent of the atmosphere and is a constituent of all proteins and nucleic acids.
nitrogen 13  a radioactive isotope of nitrogen having a half-life of 9.97 minutes and decaying by positron emission (1.190 MeV); used as a tracer in positron emission tomography.
nitrogen mustard  see under mustard.
nonprotein nitrogen  the nitrogenous constituents of the blood exclusive of the protein bodies, consisting of the nitrogen of urea, uric acid, creatine, creatinine, amino acids, polypeptides, and an undetermined part known as rest nitrogen.

nitrogen (N)

[nī′trəjən]
Etymology: Gk, nitron, soda, genein, to produce
a gaseous nonmetallic element. Its atomic number is 7; its atomic mass is 14.008. It exists as a diatomic molecule, N2. Nitrogen constitutes approximately 78% of the atmosphere and is a component of all proteins and a major component of most organic substances in living cells. Nitrogen is essential to the synthesis of necessary proteins, particularly nitrogen-containing compounds or amino acids derived directly or indirectly from plant food. Nitrogen follows a cycle from atmospheric gas into nitrogen-fixing bacteria, into green vascular plants, into humans and animals, and, by decay or in excreted nitrogenous wastes, as urea, back into the soil. Denitrifying bacteria in the soil break down nitrogenous compounds and release gaseous nitrogen. During a 24-hour period in a healthy individual the nitrogen excreted in the urine, feces, and perspiration, together with the nitrogen retained in dermal structures, such as the skin and hair, equals the nitrogen consumed in food and drink. The process of protein metabolism accounts for this nitrogen balance. When protein catabolism exceeds protein anabolism, the amount of nitrogen in the urine exceeds the amount of nitrogen consumed in foods, producing a negative nitrogen balance or a state of tissue wasting. A positive nitrogen balance exists in the body when the nitrogen intake in foods is greater than that excreted in urine. Conditions usually associated with positive nitrogen balance include those related to growth, pregnancy, and convalescence from a tissue-wasting illness. nitrogenous, adj.

nitrogen

A gaseous element (atomic number 7; atomic weight 14.01) that is present in biological systems either as the molecular form, N2, or bound to other elements, such as oxygen (i.e., nitric oxide, a neurotransmitter). Nitrogen is critical to all biological systems and is present in proteins and DNA.

ni·tro·gen

(nī'trŏ-jĕn)
1. A gaseous element; atomic no. 7, atomic wt. 14.00674; forms about 78.084% by volume of the dry atmosphere.
2. The molecular form of nitrogen, N2.
3. Pharmaceutical grade N2, containing not less than 99.0% by volume of N2; used as a diluent for medicinal gases, and for air replacement in pharmaceutical preparations.
[L. nitrum, niter, + -gen, to produce]

nitrogen

(ni'tro-jen) [ nitro- + -gen] N
A colorless, odorless, tasteless, gaseous chemical element, atomic weight (mass) 14.0067, atomic number 7. It occurs free in the atmosphere and forms approx. 80% of the volume of the atmosphere.
CAS # 7727-37-9

A component of all proteins, nitrogen is essential to plant and animal life for tissue building. Generally it is found organically only in the form of compounds such as ammonia, nitrites, and nitrates. These are transformed by plants into proteins and, being consumed by animals, are converted into animal proteins of the blood and tissues.

nitrogen dioxide

NO2, a toxic greenhouse gas, produced primarily by the combustion of fossil fuels. It is a powerful oxidant that can cause lung injury when inhaled at high concentrations.
CAS # 10102-44-0
Enlarge picture
LIQUID NITROGEN

liquid nitrogen

Nitrogen cooled to 77K (77°C above absolute zero). Liquid nitrogen is used to cool or freeze body parts, esp. the skin, in anesthesia and some surgeries. See: illustration

nitrogen monoxide

Nitric oxide.

nonprotein nitrogen

Compounds in animal nutrition that can be converted to nitrogen sources in ruminant animals. Urea, biuret, and ammonia are three examples.

nitrogen

An inert, colourless and odourless gas constituting about 80% of the atmosphere. The element is present in all proteins and occurs in the urine in the form of urea. Under pressure, considerable nitrogen will dissolve in the blood. The release of gaseous nitrogen in the blood in bubbles that can block small arteries is the chief danger in too sudden decompression in divers.

Nitrogen

A gaseous element that makes up the base pairs in DNA.
Mentioned in: Gene Therapy

liquid nitrogen

compressed, liquefied nitrogen gas at -196°C; expands rapidly on release into air and cooling its surroundings; applied (as a spray) to destroy minor skin lesions, e.g. basal cell carcinoma, verrucae (induces formation of intranuclear ice crystals, disrupts viral DNA, ruptures cell membranes and triggers an immune response)

ni·tro·gen

(N) (nī'trŏ-jĕn)
A gaseous element that forms about 78.084% by volume of dry atmosphere; used as a diluent for medicinal gases, and for air replacement in pharmaceutical preparations.
[L. nitrum, niter, + -gen, to produce]

nitrogen (N),

n a gaseous, nonmetallic element. Its atomic number is 7 and its atomic weight is 14.0067. It constitutes approximately 78% of the atmosphere and is a component of all proteins and a major component of most organic substances.
nitrogen monoxide,
nitrogen monoxidum,
nitrogen, nonprotein,

nitrogen

a chemical element, atomic number 7, atomic weight 14.007, symbol N. See Table 6. It is a gas constituting about four-fifths of common air; chemically it is almost inert. It is not poisonous but is fatal if breathed alone because of oxygen deprivation. Nitrogen occurs in proteins and amino acids and is thus present in all living cells.

nitrogen balance
the state of the body in regard to the rate of protein intake and protein utilization. When protein is metabolized, about 90% of the protein nitrogen is excreted in the urine in the form of urea, uric acid, creatinine and other nitrogen end products. The remaining 10% of the nitrogen is eliminated in the feces.
A negative nitrogen balance occurs when more protein is utilized by the body than is taken in. A positive nitrogen balance implies a net gain of protein in the body. Negative nitrogen balance can be caused by such factors as malnutrition, debilitating diseases, blood loss and glucocorticoids. A positive balance can be caused by exercise, growth hormone and testosterone.
blood urea nitrogen (BUN)
see urea nitrogen.
nitrogen dioxide
see nitric oxide.
nitrogen fixation
conversion of atmospheric nitrogen into organic nitrogenous compounds by bacteria which may be symbiotic, e.g. Rhizopus spp., which grow on the roots of legumes and put those plants in an advantageous position with respect to nonlegumes.
nitrogen-free extract (NFE)
consists of carbohydrates, sugars, starches, and a major portion of the hemicellulose in feeds. Calculated when crude protein, fat, water, ash, and the fiber are added and the sum is subtracted from 100.
nitrogen mustards
a group of toxic, blistering alkylating agents homologous to dichlorodiethyl sulfide (mustard gas), some of which have been used as antineoplastics. The group includes mustine hydrochloride, cyclophosphamide, thiotepa, chlorambucil and melphalan.
nonprotein nitrogen (NPN)
1. the nitrogenous constituents of the blood exclusive of the protein bodies, consisting of the nitrogen of urea, uric acid, creatine, creatinine, amino acids, polypeptides, and an undetermined part known as rest nitrogen.
Measurement of nonprotein nitrogen is used as a test of renal function, but has been largely replaced by measurement of specific substances, e.g. urea and creatinine.
2. also used in relation to feeds and refers to those nitrogen-containing constituents which are not proteins, e.g. nucleic acids, amino sugars, urea, etc.
nitrogen trichloride
nitrogen washout test
measures the rate at which the nitrogen concentration in the expired air is reduced when the horse is made to breathe pure oxygen. The rate is less in incompetent lungs, e.g. those affected by emphysema.
References in periodicals archive ?
Denitrification and dinitrogen fixation in two quaking fens in the Vechtplassen area, The Netherlands.
Scientists have also found Richelia, cyanobacteria with specialized cells for fixing dinitrogen that live inside single-celled marine plants, including some diatoms.
Nitrogen deposition is of a higher order of magnitude than that of phosphorus; it includes dissolved dinitrogen, the products of chemical fixation, and some organic compounds as well.
Zaman M, Nguyen M, Matheson F, Blennerhassett J, Quin B (2007) Can soil amendments (zeolite or lime) shift the balance between nitrous oxide and dinitrogen emissions from pasture and wetland soils receiving urine or urea-N?
Dinitrogen fixation is thus a decisive physiological parameter both for enhanced productivity and higher seed quality, traits often reported as negatively correlated [2].
Indoor ozone and nitrogen-dioxide--a potential pathway to the generation of nitrate radicals, dinitrogen pentaoxide, and nitric-acid indoors.
Owing to the ability to fix dinitrogen by the symbiosis of actinomycetes Frankia in alder root nodules, the soil under alders is enriching by nitrogen, mainly via above- and below-ground litter.
Our central hypothesis was that declines in macrophyte diversity would cause decreases in microbial diversity and significantly increase the flux of nitrous oxide relative to that of dinitrogen gas.
9 Dinitrogen Pentoxide - An Eco-Friendly Nitrating Agent.
Dinitrogen tetroxide (NTO) was used for the first time to cool one section of the combustion chamber by the team, during testing.
Even with more than 99 percent of denitrified nitrogen in streams and rivers being converted to the inert gas, dinitrogen, river networks still contribute to at least 10 percent of global anthropogenic nitrous oxide emissions," Hamilton said.