Membrane screens

C. Immobilized artifidal membranes -screens for drug-membrane interactions. Adv. Drug Del. Revs. 1996, 23, 229-256. 

PDA vesicles have been used to screen small molecules that are known to interact with membranes. Screening of almost 40 compounds against PDA/DMPC liposomes... 

Filters can be divided into two types membrane (screen) filters and depth filters. Membrane filters, such as silver membrane filters, physically screen and retain particles on their surfaces. These filters have uniform pore sizes and are rated for absolute retention all particles larger than the pore size are retained. Depth filters, such as glass-fiber filters, consist of a matrix of fibers that form a tortuous maze of flow channels. The particulate fraction becomes entrapped by this matrix. These filters do not have a uniform pore size, and it is not possible to rate them for absolute retention. They are rated according to nominal pore size, which is determined by the particle size that is retained by the filter to a predetermined percentage. This percentage is usually given as 98 retention however, it can be as low as 90. ... 

Membrane-Screening Test Membrane-screening tests were performed to evaluate (1) the adequacy of flushing procedures, (2) the rejection of model compounds by the RO membrane, and (3) losses of model compounds to system components via adsorption, volatilization, solubility artifacts, or other phenomena. 

Jawaheer et al. [12] Fruits (maturity and quality) Glucose oxidase, mutarotase, invertase/ pectin matrix and covered with a cellulose acetate (CA) membrane Screen-printed rhodinised carbon electrodes/ +350mV vs. Ag/AgCl ... 

J.S. D Arrigo, Strontium ions and membranes screening versus binding at charges surfaces, in S.C. Skoryna (Ed.), Handbook of Stable Strontium, Plenum, New York, 1981, pp. 167-182. 

However, the short lifetime of in-line cartridge filters makes them unsuitable for microfiltration of highly contaminated feed streams. Cross-flow filtration, which overlaps significantly with ultrafiltration technology, described in Chapter 6, is used in such applications. In cross-flow filtration, long filter life is achieved by sweeping the majority of the retained particles from the membrane surface before they enter the membrane. Screen filters are preferred for this application, and an ultrafiltration membrane can be used. The design of such membranes and modules is covered under ultrafiltration (Chapter 6) and will not be repeated here. 

Yang CY, Cai SJ, Liu H, Pidgeon C. Immobilized artificial membranes — screens for drug membrane interactions. Adv Drug Del. Rev 1997 23 229-56. 

CY Yang, SJ Cai, H Liu, C Pidgeon. Immobilized artificial membranes—screens for drug membrane interactions. Adv Drug Del Rev 23 229—256, 1996. 

Filters can be divided into two types membrane (screen) filters and depth filters. Membrane filters, such as silver-membrane filters or cellulose-acetate and cellulose-nitrate filters, physically sieve and retain particles on their surfaces. These filters have uniform pore sizes and are rated for absolute... 

Continue polymer synthesis and evaluation of the fabricated films per membrane screening specifications. Initiate the fabrication of initial promising candidates into CCMs. 

To serve as a preliminary membrane screening method, the methanol permeability was measured for a number of Nafion -type samples by the... 

To serve as a preliminary membrane screening method, the methanol permeability was measured for a number of samples by using an apparatus to sandwich the membrane between two solutions of known concentration as described previously. As illustrated in Fig. 1.71, the amount of methanol which was observed to permeate across a PSSA-PVDF membrane is roughly half the amount observed with Nation 117. This behavior of lower methanol... 

Figure 9.4 Immobilized artificial membrane lAM) chromatography. Binding of solute to fluid membranes in (A) can be modeled by solute binding to an immobilized membrane as in (B) through measurement of iam as shown in (C). (Reprinted with permission from Yang, C.Y., el al. Immobilized artificial membranes—Screens for drug membrane interactions. Adv. Drug Deliv. Rev. 1996, 23 229-256, copyright 1997, Elsevier).

These circulation rates give about a one psi difference between the electrolyte compartment and the anolyte and catholyte compartments. The difference is required to keep the membranes apart and against the membrane screens, thus maintaining a constant distance between membranes. 

Similar to the gas chromatographic method where the methanol concentration of the receiving compartment (Cg(t)) is monitored with time, in a variation of this method the receiving compartment can be connected to a vacnnm system that allows pervaporation of the crossed methanol [34], The vaporized methanol is collected in cryogenic traps. This method could be cumbersome, and like gas chromatography is useful only for membrane screening since it does not simulate fuel cell conditions well. 

Fig. 2 Examples of membrane screening tests, (a) Typical Fenton s test results, (b) Relative humidity cycle profile, (c) Typical gas crossover data resulting from the relative humidity (RH) test...

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