Membrane surface treatments

Such layers are usually made of highly cross-linked material and show good adhesion to the substrate. Examples of such membrane surface treatment are plasma polymerization of allyl alcohol and allyl amine (Gancarz et al. 2002, 2003). It was shown that the membranes modified with allyl amine do not foul as intensively during UF of the BSA solutions compared with the unmodified membranes. Similar behavior was also shown for membranes modified by the deposition of plasma-polymerized n-butylamine however, in this case, the modified layer deposited on the manbrane surface was not as enriched in amines as the polymer formed from aUyl amine (Gancarz et al. 2002). 

Several cleaning methods are used to remove the densified gel layer of retained material from the membrane surface. Alkaline solutions followed by hot detergent solutions are indicated for organic polymer colloids and gelatinous materials fouling. Ferrous deposits, t3 pical in water treatments, are usually removed with a citric or hydrochloric wash. [35]. 

A study on surface treatment of Nation membrane and its effects on cell performance... 

Detection of Li+ in artificial serum with a voltammetric Li-selective electrode in a flowthrough system was demonstrated [64], Lithium salts such as lithium carbonate have been extensively used for treatment of manic depressive and hyperthyroidism disorders. The therapeutic range of Li concentration is generally accepted to be 0.5-1.5mM in blood serum. The authors used normal pulse voltammetry in which a stripping potential was applied between pulses in order to renew the membrane surface and expel all of the extracted ions from the membrane, similar to galvanostatically controlled potentiometric sensors described above. Unfortunately, the insufficient selectivity... 

Polymer-based pH sensors are not suitable for continuous in-vivo measurements due to the poor biocompatibility of plasticizers used in the polymer membrane. To minimize such a problem, surface treatment or using a reduced amount of plasticizers has been proposed [71]. In order to improve stability and adhesion, polyurethane has been used as an alternative to PVC membranes in the construction of pH sensing membranes [72, 73],... 

Many industrial yams have specific surface function requirements. For technical yams the market share for composites or coated fabrics is almost 70%. Furthermore, textile applications also can benefit from a special surface treatment in order to improve the water repellency. Capillary membranes for dialysis, however, have totally different requirements enhanced biocompatibility of the membranes is needed.4-6... 

Another approach to enhance separation performance of membrane for dehydration of isopropanol is the modification of PVA membranes in gaseous plasma [30], The modification of membrane properties in nitrogen plasma environment lead to increase in selectivity by about 1477 at 25 °C such increase in the selectivity is justified by an increase of cross-linking on membrane surface provoked by plasma treatment. 

In a previous section, the effect of plasma on PVA surface for pervaporation processes was also mentioned. In fact, plasma treatment is a surface-modification method to control the hydrophilicity-hydrophobicity balance of polymer materials in order to optimize their properties in various domains, such as adhesion, biocompatibility and membrane-separation techniques. Non-porous PVA membranes were prepared by the cast-evaporating method and covered with an allyl alcohol or acrylic acid plasma-polymerized layer the effect of plasma treatment on the increase of PVA membrane surface hydrophobicity was checked [37].The allyl alcohol plasma layer was weakly crosslinked, in contrast to the acrylic acid layer. The best results for the dehydration of ethanol were obtained using allyl alcohol treatment. The selectivity of treated membrane (H20 wt% in the pervaporate in the range 83-92 and a water selectivity, aH2o, of 250 at 25 °C) is higher than that of the non-treated one (aH2o = 19) as well as that of the acrylic acid treated membrane (aH2o = 22). 

Membrane composition Zeolite surface- treatment method Geometry Applications Reference... 

Superficial fungal infections involve cutaneous surfaces, such as the skin, nails, and hair, and mucous membrane surfaces, such as the oropharynx and vagina. A growing number of topical and systemic agents are available for the treatment of these infections. Deep-... 

Miconazole (Monistat) is a broad-spectrum imidazole antifungal agent used in the topical treatment of cutaneous dermatophyte infections and mucous membrane Candida infections, such as vaginitis. Minimal absorption occurs from skin or mucous membrane surfaces. Local irritation to skin and mucous membranes can occur with topical use headaches, urticaria, and abdominal cramping have been reported with treatment for vagiiutis. 

Treatment of the above SHG curves for membranes 80, 83, 85, and 86 by a Langmuir-isotherm type analysis indicates Langmuir-type saturation occurring at the membrane surface at high cation concentrations, which may be interpreted in terms of a tightly packed monolayer of the SHG active cation complexes at the membrane surface. However, the SHG active layer may actually have a thickness of several monolayers if the electrical field aligns the complexes with respect to the interface. 

Thus, the fat globules are surrounded, at least initially, by a membrane typical of eukaryotic cells. Membranes are a conspicuous feature of all cells and may represent 80% of the dry weight of some cells. They serve as barriers separating aqueous compartments with different solute composition and as the structural base on which many enzymes and transport systems are located. Although there is considerable variation, the typical composition of membranes is about 40% lipid and 60% protein. The lipids are mostly polar (nearly all the polar lipids in cells are located in the membranes), principally phospholipids and cholesterol in varying proportions. Membranes contain several proteins, perhaps up to 100 in complex membranes. Some of the proteins, referred to as extrinsic or peripheral, are loosely attached to the membrane surface and are easily removed by mild extraction procedures. The intrinsic or integral proteins, about 70% of the total protein, are tightly bound to the lipid portion and are removed only by severe treatment, e.g. by SDS or urea. 

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