this is a comprehensive review of the recent progresses made in the field of zeolite membranes. it describes zeolitic materials and methods of membrane fabrication, followed by a summary of applications for gas separation, pervaporation and separation of liquid mixtures. special attention is called to polymer mixed matrix membranes (mmms) and membranes based on metal organic frame works (mofs)....

This work focuses on identifying the rate-determining step of oxygen transport through La0.5Sr0.5Fe0.7Ga0.3O3-? membranes with symmetric and asymmetric architectures. The best semipermeation fluxes are 3.4 10?3 mol. m-2.s-1 6.3 at 900 °C for membrane a modified surface. surface leads to an increase approximately 7 times flux compared that obtained dense without modification. also shows is mainl...

Caulobacter crescentus divides asymmetrically and creates distinct polar membrane surfaces that partition during the cell cycle to distinct cell progeny. Blocking membrane synthesis prevented transcription from selective promoters involved in asymmetric cell division. Transcription from sigma-54-dependent flagellar promoters was blocked completely; however, transcription from the CtrA response ...

As part of a study on the mechanisms of leukocyte filtration, the influence of pore size distribution on filter efficiency was investigated. Conventional leukocyte filters are not suitable for model studies, as these filters are composed of tightly packed synthetic fibers, with a poorly defined porous structure. Therefore, open cellular polyurethane membranes with pore size distributions varyin...

Osmotic drug delivery mechanism is well known in the field of oral controlled release systems. The release of drug from the osmotic drug delivery devices is based on the phenomenon of osmosis. An useful technology developed for osmotic delivery of drug is asymmetric membrane capsule (AMC), which is an economic and effective drug delivery device as compared to other existing technique of osmotic...

The incorporation of labeled fatty acids into phosphatidylethanolamine (PE) on the two sides of the human red cell membrane was studied by use of the vectorial probe trinitrobenzene sulfonate (TNBS). A small population of PE molecules on the outer surface of the membrane has a 4-fold higher turnover rate than the remaining PE molecules. This effect is greatest with palmitic acid, less with lino...

A computational method is developed to allow molecular dynamics simulations of biomembrane systems under realistic ionic gradients and asymmetric salt concentrations while maintaining the conventional periodic boundary conditions required to minimize finite-size effects in an all-atom explicit solvent representation. The method, which consists of introducing a nonperiodic energy step acting on ...

The area balance or imbalance between the inner and outer monolayer of biological membranes is a key parameter for driving shape changes (including exo and endocytosis) and controlling the bilayer curvature stress. The asymmetric incorporation of a drug or biological agent interferes with these processes, and the subsequent stress may lead to a membrane permeation or permeabilization. A main go...

This study proposes using membrane distillation (MD) as an alternative to the conventional multi-stage flushing (MSF) process to concentrate a semi-product of organic fertilizer. By applying a unique asymmetric polyvinylidene fluoride (PVDF) membrane, which was specifically designed for MD applications using a nonsolvent thermally induced phase separation (NTIPS) method, the direct contact memb...