窒素平衡

WordNet

a stable situation in which forces cancel one another
a sensory system located in structures of the inner ear that registers the orientation of the head (同)labyrinthine sense, vestibular sense, sense of balance, sense_of_equilibrium
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 (同)N, atomic number 7

PrepTutorEJDIC

(力・勢力・作用などの)釣り合い,均衡;(心の)平静
『窒素』(気体元素;化学記号は『N』)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/24 05:47:35」(JST)

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Nitrogen balance is a measure of nitrogen input minus nitrogen output.^[1]

Nitrogen Balance = Nitrogen intake - Nitrogen loss

Sources of nitrogen intake include meat, dairy, eggs, nuts and legumes, and grains and cereals. Examples of nitrogen losses include urine, feces, sweat, hair, and skin.

Blood urea nitrogen can be used in estimating nitrogen balance, as can the urea concentration in urine.

Nitrogen Balance and Protein Metabolism

Nitrogen is a fundamental component of amino acids, which are the molecular building blocks of protein. Therefore, measuring nitrogen inputs and losses can be used to study protein metabolism ^[2]

Positive nitrogen balance is associated with periods of growth, hypothyroidism, tissue repair, and pregnancy. This means that the intake of nitrogen into the body is greater than the loss of nitrogen from the body, so there is an increase in the total body pool of protein.

Negative nitrogen balance is associated with burns, serious tissue injuries, fevers, hyperthyroidism, wasting diseases, and during periods of fasting. This means that the amount of nitrogen excreted from the body is greater than the amount of nitrogen ingested.^[3] A negative nitrogen balance can be used as part of a clinical evaluation of malnutrition.^[4]

Nitrogen balance is the traditional method of determining dietary protein requirements.^[5] Determining dietary protein requirements using nitrogen balance requires that all nitrogen inputs and losses are carefully collected, to ensure that all nitrogen exchange is accounted for.^[6] In order to control nitrogen inputs and losses, nitrogen balance studies usually require participants to eat very specific diets (so total nitrogen intake is known) and stay in the study location for the duration of the study (to collect all nitrogen losses). Because of these conditions, it can be difficult to study the dietary protein requirements of certain populations using the nitrogen balance technique (e.g. children).^[7]

References

^ "Definition: nitrogen balance from Online Medical Dictionary".
^ World Health Organization Protein and amino acid requirements in human nutrition. WHO Technical Report Series 935 [1]
^ "VII. Monitoring Nutrition Therapy".
^ Barbosa-Silva MC (May 2008). "Subjective and objective nutritional assessment methods: what do they really assess?". Curr Opin Clin Nutr Metab Care 11 (3): 248–54. doi:10.1097/MCO.0b013e3282fba5d7. PMID 18403920.
^ Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids (Macronutrients). The National Academies Press: 2005
^ Rand WM, Pellett PL, Young VR (2003). Meta-analysis of nitrogen balance studies for estimating protein requirements in health adults. Am.J.Nutr 77(1):109-127.
^ Elango R, Humayun MA, Ball RO, Pencharz PB (2011). Protein requirements of healthy, school-aged children determined by the indicator amino acid oxidation method. Am. J. Clin. Nutr. 94(6): 1545-1552.

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English Journal

Evaluation of PAN-based manganese dioxide composite for the sorptive removal of cesium-137 from aqueous solutions.

Nilchi A, Saberi R, Garmarodi SR, Bagheri A.SourceNSTR, Tehran, Iran. anilchi@aeoi.org.ir
Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.Appl Radiat Isot.2012 Feb;70(2):369-74. Epub 2011 Nov 6.
Hydrous manganese dioxide-polyacrylonitrile (MnO(2)-PAN) was chemically synthesized and evaluated, as an organic-inorganic composite material, for the removal of radio-contaminant cesium-137 from aqueous solutions. The physico-chemical characterization was carried out by Fourier transform infrared s
PMID 22078459

Influence of relative humidity and gaseous ammonia on the nicotine sorption to indoor materials.

Ongwandee M, Sawanyapanich P.SourceFaculty of Engineering, Mahasarakham University, Mahasarakham, Thailand.
Indoor air.Indoor Air.2012 Feb;22(1):54-63. doi: 10.1111/j.1600-0668.2011.00737.x. Epub 2011 Sep 14.
Abstract Sorption of nitrogen-containing organic constituents of environmental tobacco smoke may be influenced by ammonia, a common indoor gas, and relative humidity (RH). We quantified sorption kinetics and equilibria of nicotine with stainless steel, cotton-polyester curtain, and polypropylene
PMID 21913993