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(of a membrane) selectively permeable

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(膜などが)半透性の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/12/31 15:25:22」(JST)

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Scheme of semipermeable membrane during hemodialysis, where blood is red, dialysing fluid is blue, and the membrane is yellow.

A semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".

The rate of passage depends on the pressure, concentration, and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute. Depending on the membrane and the solute, permeability may depend on solute size, solubility, properties, or chemistry. How the membrane is constructed to be selective in its permeability will determine the rate and the permeability. Many natural and synthetic materials thicker than a membrane are also semipermeable. One example of this is the thin film on the inside of an egg.

An example of a semi-permeable membrane is the lipid bilayer, on which is based the plasma membrane that surrounds all biological cells. A group of phospholipids (consisting of a phosphate head and two fatty acid tails) arranged into a double-layer, the phospholipid bilayer is a semipermeable membrane that is very specific in its permeability. The hydrophilic phosphate heads are in the outside layer and exposed to the water content outside and within the cell. The hydrophobic tails are the layer hidden in the inside of the membrane. The phospholipid bilayer is the most permeable to small, uncharged solutes. Protein channels float through the phospholipids, and, collectively, this model is known as the fluid mosaic model.

In the process of reverse osmosis, thin film composite membranes (TFC or TFM) are used. These are semipermeable membranes manufactured principally for use in water purification or desalination systems. They also have use in chemical applications such as batteries and fuel cells. In essence, a TFC material is a molecular sieve constructed in the form of a film from two or more layered materials.

Membranes used in reverse osmosis are, in general, made out of polyimide, chosen primarily for its permeability to water and relative impermeability to various dissolved impurities including salt ions and other small molecules that cannot be filtered. Another example of a semipermeable membrane is dialysis tubing.

Other types are cation exchange membrane (CEM), charge mosaic membrane (CMM), bipolar membrane (BPM), anion exchange membrane (AEM)^[1] alkali anion exchange membrane (AAEM) and proton exchange membrane (PEM).

The diffusion of water through a selectively permeable membrane is called osmosis.

References

^ Effect of the type of ion exchange membrane on performance, ion transport, and pH in biocatalyzed electrolysis of wastewater

External links

EuroMemHouse - European Membrane House
Membrane terminology. International Union of Pure and Applied Chemistry recommendations.

UpToDate Contents

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1. 糖尿病性足病変のマネージメント management of diabetic foot lesions
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3. 血液透析装置の概要 overview of the hemodialysis apparatus
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English Journal

Effects of the use of semipermeable membranes on fluid loss in low-birth-weight premature newborns.

de Paula Pessoa Gurgel E, de Oliveira Lopes MV, Caetano JÁ, Rolim KM, de Almeida PC, Barreto JO.SourceDepartment of Nursing, University of Fortaleza, Fortaleza, Brazil.
Biological research for nursing.Biol Res Nurs.2013 Apr;15(2):200-4. doi: 10.1177/1099800411423097. Epub 2011 Oct 9.
Studies have shown that the application of semipermeable membranes to the skin of premature newborns (NBs) can aid in protecting the skin, reduce disturbances in fluid and electrolyte levels, and decrease neonatal mortality. The aim of this study was to verify the effect of using semipermeable membr
PMID 21987832

Using pullulan-based edible coatings to extend shelf-life of fresh-cut 'Fuji' apples.

Wu S, Chen J.SourceSchool of Marine Science and Technology, Huaihai Institute of Technology, 59 Cangwu Road, Xinpu 222005, China. Electronic address: wushengjun008@sina.com.
International journal of biological macromolecules.Int J Biol Macromol.2013 Apr;55:254-7. doi: 10.1016/j.ijbiomac.2013.01.012. Epub 2013 Jan 31.
Pullulan is a thickener that can form semipermeable films, and glutathione is an effective reducing agent, while chitooligosaccharide has antibacterial activity. In this study, effect of pullulan-based coatings in combination with antibrowning and antibacterial agents (1% pullulan; 0.8% glutathione+
PMID 23376560

The local treatment and available dressings designed for chronic wounds.

Skórkowska-Telichowska K, Czemplik M, Kulma A, Szopa J.SourceDepartment of Endocrinology, Internal Disease Clinic in 4th Military Academic Hospital in Wrocław, Wrocław, Poland.
Journal of the American Academy of Dermatology.J Am Acad Dermatol.2013 Apr;68(4):e117-26. doi: 10.1016/j.jaad.2011.06.028. Epub 2011 Oct 7.
The great diversity of wounds and the broad range of available dressings complicate the selection of proper chronic wound treatment. Choosing the right treatment is the essential step in the healing process. In this review, we focus on chronic nonhealing ulcers, which are a critical problem in clini
PMID 21982060

Japanese Journal

ベンゼンに汚染された難透水性土壌への高圧空気注入を併用した通水洗浄の適用性検討

桐山久,峠和男,竹崎聡,西田憲司,佐藤健
廃棄物資源循環学会論文誌 = Journal of the Japan Society of Material Cycles and Waste Management 23(2), 67-76, 2012-03-31
難透水層に浸透した汚染物質に対する原位置浄化は，透水性・透気性が小さいことなどから従来困難とされていた。そこで筆者らは，ベンゼンに汚染された難透水層を対象として，通水洗浄と高圧空気間欠注入を組み合わせた浄化工法を提案し，浄化要素別に基礎的研究を行うことにより，浄化工法の難透水性土壌への適用性を調査した。室内試験の結果，高圧空気間欠注入は難透水層への空気注入が可能な方法であった。また，土壌から水へベ …
NAID 10030120656

Transition of velocity distributions in collapsing self-gravitating N-body systems

Komatsu Nobuyoshi,Kiwata Takahiro,Kimura Shigeo
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 85(2), 021132, 2012-02-22
… To simulate the dynamical evolution, we consider self-gravitating small N-body systems enclosed in a spherical container with adiabatic or semipermeable walls. …
NAID 120003959458

CT造影製剤特性が造影効果に及ぼす影響

寺澤和晶,八町淳,奥田逸子
日本放射線技術學會雜誌 67(12), 1583-1591, 2011-12-20
… Using a custom-made phantom incorporating a semipermeable membrane, the osmotic flow rate (HU/s) could easily be measured based on the observed increase in CT numbers, and the relationship between the osmotic pressure and the osmotic flow rate could be obtained (r2=0.84). …
NAID 10030042642