liquid nitrogen


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Related to liquid nitrogen: dry ice

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.

liquid nitrogen

See cryogen.
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
See also: nitrogen

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)

liquid

1. a substance that flows readily in its natural state.
2. flowing readily; neither solid nor gaseous.

liquid diet
a diet limited to the intake of liquids or foods that can be changed to a liquid state.
liquid nitrogen
compressed nitrogen in liquid form; used as a supercoolant in freezing semen, and in cryosurgery.
liquid paraffin, liquid petrolatum
see mineral oil.
References in periodicals archive ?
Other than the recent case of the Delhi-based man, in 2012, a young woman in England had her stomach removed after ingesting a cocktail made with liquid nitrogen.
The former Milford Haven Comprehensive School pupil said: "Making ice cream with liquid nitrogen means you can freeze it instantly at a temperature of -330F (around -200C).
Making liquid nitrogen requires a great deal of electric energy, as the liquefaction point of nitrogen is below -210 degrees C, but as 80 percent of uses for nitrogen are as a gas and not a liquid the only reason it is liquefied is for ease of transportation, which, as indicated above, contributes to loss on two fronts.
DEEP FREEZE: Hazel Smith tries liquid nitrogen frozen ice cream made by David Clokey and Craig McDonald of The Gray Ox, Hartshead, at the Mirfield Show, and, right, their inspiration TV chef Heston Blumenthal (JH210811Bmirfield)
By construction, the liquid nitrogen cooling installation can be used for the other basic procedures in metal cutting, i.
Using liquid nitrogen coolant, a $15 off-the-shelf, four-tipped ceramic insert can replace a $50 carbide-tipped insert.
Learn about safety when handling cryogens, including liquid nitrogen, at: www-safety.
Company developed a method to meter liquid nitrogen into composite, glass and plastic containers effectively purging the container of oxygen.
In conclusion, with the aid of dextrose and PEG cloned buffalo grass can be placed in liquid nitrogen to help preserve plant genetic conservation.
will show several new models, including its NitroDoser liquid nitrogen dispensing system.
By maintaining the storage cell at liquid nitrogen temperature during compression, the density has been increased by a factor of four.