WordNet

unconstrained or not chemically bound in a molecule or not fixed and capable of relatively unrestricted motion; "free expansion"; "free oxygen"; "a free electron"
people who are free; "the home of the free and the brave" (同)free people
free from obligations or duties (同)discharge
free or remove obstruction from; "free a path across the cluttered floor" (同)disengage
grant freedom to; free from confinement (同)liberate, release, unloose, unloosen, loose
not literal; "a loose interpretation of what she had been told"; "a free translation of the poem" (同)loose, liberal
make (information) available for publication; "release the list with the names of the prisoners" (同)release
able to act at will; not hampered; not under compulsion or restraint; "free enterprise"; "a free port"; "a free country"; "I have an hour free"; "free will"; "free of racism"; "feel free to stay as long as you wish"; "a free choice"
not held in servitude; "after the Civil War he was a free man"
not occupied or in use; "a free locker"; "a free lane"
provide with water; "We watered the buffalo"
binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent (同)H2O
supply with water, as with channels or ditches or streams; "Water the fields" (同)irrigate
once thought to be one of four elements composing the universe (Empedocles)
secrete or form water, as tears or saliva; "My mouth watered at the prospect of a good dinner"; "His eyes watered"
a liquid necessary for the life of most animals and plants; "he asked for a drink of water"
fill with tears; "His eyes were watering"
permission to proceed; "the plane was given clearance to land"
the distance by which one thing clears another; the space between them
wetting with water; "the lawn needs a great deal of watering"

PrepTutorEJDIC

(束縛された状態になく)『自由な』,自由の身の / (国家・国民などが)『独立している』 / (思想・行為などが)強制されない,自発的な / (動作が)拘束されない,無理のない / 《補語にのみ用いて》(苦痛・制約などを)『免れている』,(誤り・偏見などの)ない《+『from』(『of』)+『名』》 / 《補語にのみ用いて》《『be free to』do》『自由に』…『できる』 / (仕事から)解放された,暇になった;(部屋などが)使用されていない,空いた / 『無料の』;無税の / 出し惜しみしない / 遠慮のない,慎みがない / (道路などが)障害のない,自由に通れる / 固定していない,離れた / 無料で / 自由に,妨げられずに(freely) / (…から)〈人・国など〉‘を'『自由にする』,解放する《+『名』+『from』+『名』》 / (困難などから)〈人〉‘を'救う《+『名』+『form』+『名』》 / (障害などを)〈人・物〉‘から'取り除く《+『名』+『of』(『from』)+『名』》 / (物を)…‘から'片付ける,外す《+『名』+『of』+『名』》
〈U〉水 / 《しばしば複数形で》『海』(『湖,川』)『の水』 / 《複数形で》流れる水;(海・川・湖などの)波立つ水《+of+名》 / 《複数形で》(特定の)水域,領海,近海 / 〈U〉潮位,水位;《the water》水面 / 〈U〉分泌液(涙・汗・尿など) / 〈U〉溶液,…水 / 《複数形で》(飲用の)鉱泉水 / 〈U〉(織物・金属などの)波紋 / …‘に'『水をかける』(まく,やる) / 〈動物〉‘に'水を飲ませる / …‘に'水を供給する;…‘を'潅漑(かんがい)する / 〈液体など〉‘を'水で割る,薄める《+名+down,+down+名》 / 〈織物・金属など〉‘に'波紋(波模様)をつける / 〈動物などが〉水を飲む:〈船・機関などが〉給水を受ける / 〈目・口などが〉分泌液を出す
〈U〉〈C〉(…の)取り片付け,除去,掃除《+『of』+『名』》 / 〈U〉〈C〉(積荷の)通関手続き,(船の)出港免状 / (またclearance sale)〈C〉大棚ざらいの売出し / 〈U〉〈C〉(手形の)決済,(小切手の)現金化 / 〈U〉〈C〉(二つの物の間の)あき,余裕;(特に)道路面・川の面から橋げたまでの高さ / 〈U〉〈C〉秘密情報の使用許可;(秘密情報を扱う人の)信頼性調査;公安調査

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/03/08 13:54:11」(JST)

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In the physiology of the kidney, free water clearance (C_H₂O) is the volume of blood plasma that is cleared of solute-free water per unit time. An example of its use is in the determination of an individual's state of hydration. Conceptually, fee water clearance should be thought of relative to the production of isoosmotic urine, which would be equal to the osmolarity of the plasma. If an individual is producing urine more dilute than the plasma, there is a positive value for free water clearance, meaning pure water is lost in the urine in addition to a theoretical isoosmotic filtrate. If the urine is more concentrated than the plasma, then free water is being extracted from the urine, giving a negative value for free water clearance. A negative value is typical for free water clearance, as the kidney usually produces concentrated urine except in the cases of volume overload by the individual.

Overview

At its simplest, the kidney produces urine composed of solute and pure (solute-free) water. How rapidly the kidney clears the blood plasma of a substance (be it water or solute) is the renal clearance, which is related to the rate of urine production. The rate at which plasma is cleared of solute is the osmolal clearance; the rate at which plasma is cleared of solute-free water is the free water clearance.

Calculation

Since urine flow is determined by the rate at which plasma is cleared of solutes and water (as discussed above), urine flow (V) is given as the sum of osmolar (C_osm) and free water clearance (C_H₂O):

V=C_{osm}+C_{H_{2}O}

Rearranging yields C_H₂O

C_{H_{2}O}=V-C_{osm}

Since osmolar clearance is given as the product of urine flow rate and the ratio of urine to plasma osmolality, this is commonly represented as

C_{H_{2}O}=V-{\frac {U_{osm}}{P_{osm}}}V=(1-{\frac {U_{osm}}{P_{osm}}})V

For example, for an individual with a urine osmolality of 140 mOsm/L, plasma osmolality of 280 mOsm/L, and a urine production of 4 ml/min, the free water clearance is 2 ml/min, obtained from

C_{H_{2}O}=4\ {\mbox{ml/min}}-{\frac {140\ {\mbox{mOsm/L}}}{280\ {\mbox{mOsm/L}}}}\times 4\ {\mbox{ml/min}}=2\ {\mbox{ml/min}}

Interpretation

Free water clearance can be used as an indicator of how the body is regulating water. A free water clearance of zero means the kidney is producing urine isosmotic with respect to the plasma. Values greater than zero imply that the kidney is producing dilute urine through the excretion of solute-free water. Values less than zero imply that the kidney is conserving water (likely under the influence of antidiuretic hormone, ADH), resulting in the production of concentrated urine.

External links

Overview at mcg.edu
Overview at mmi.mcgill.ca
Formula at mmi.mcgill.ca

UpToDate Contents

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1. 高ナトリウム血症の治療 treatment of hypernatremia
2. 水分バランス異常（低ナトリウム血症および高ナトリウム血症）およびナトリウムバランス異常（循環血液量減少および浮腫）の一般原則 general principles of disorders of water balance hyponatremia and hypernatremia and sodium balance hypovolemia and edema
3. 低ナトリウム血症患者におけるナトリウム欠乏の評価 estimation of the sodium deficit in patients with hyponatremia
4. 小児における高ナトリウム血症 hypernatremia in children
5. 成人における維持輸液療法および補充輸液療法 maintenance and replacement fluid therapy in adults

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Higashihara E1, Nutahara K, Tanbo M, Hara H, Miyazaki I, Kobayashi K, Nitatori T.
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Japanese Journal

取水槽内の空気吸込の発生について

平田勝哉,舟木治郎,久保田義啓,稲垣勝久,田岡未樹
同志社大学理工学研究報告 52(1), 1-17, 2011-04
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NAID 110008441225