this paper discusses different important gas permeation models such as “maxwell”, “bruggeman”, “lewis-neilson”, and “pal” models to predict “mixed matrix membranes” (mmms) performance. the main parameter considered and discussed is the permeability of hydrogen on carbon nanotubes (cnts)-mmm. for evaluation of the theoretical models, experimental data of permeability for h2 were compared to the ...

the permeability and tortuosity of pore-scale two and three-dimensional random porous media were calculated using the lattice boltzmann method (lbm). effects of geometrical parameters of medium on permeability and tortuosity were investigated as well. two major models of random porous media were reconstructed by computerized tomography method: randomly distributed rectangular obstacles in a uni...

BACKGROUND Vascular endothelial growth factor (VEGF), an endothelial cell mitogen that promotes angiogenesis, was initially identified as a vascular permeability factor (VPF). Abundant evidence suggests that angiogenesis is preceded and/or accompanied by enhanced microvascular permeability. The mechanism by which VEGF/VPF increases vascular permeability (VP), however, has remained enigmatic. Ac...

Accumulating evidence suggests that central thyrotropin-releasing hormone (TRH) administration induces gastric erosion 4 h after administration through the vagal nerves. However, early changes in the gastric mucosa during these 4 h have not been described. To assess early changes in the gastric mucosa after intracisternal injection of a stable TRH analog, pGlu-His-(3,3'-dimethyl)-ProNH2 (RX-773...

Unbound aggregates are the most common type of materials used for construction of the base layer of flexible pavements in Iran and worldwide. Due to the lack of binder, the performance of the compacted unbound aggregates is highly dependent on the properties of the gravel (particles remaining on sieve 4.75mm, sand (particles passing sieve 4.75mm and remaining on sieve 0....

Background—Capillary leakage with fluid loss into the third space contributes to many of the early systemic complications in severe acute pancreatitis. There has been increasing interest in endothelin as one of the factors aVecting capillary permeability. Aim—To elucidate further the role of endothelin in the development of capillary leakage in acute pancreatitis by investigating the eVect of e...

Permeability of concrete is commonly used as a key index for assessing the durability of concrete, especially when concrete is to be exposed to the aggressive environment. For a porous material like concrete, permeability depends on porosity and pore characteristics such as pore size, orientation, connectivity, and size variation. The effects of porosity and pore characteristics on permeability...

The objective of this study was to investigate the influence of physiochemical parameters (such as size, molecular weight, molecular geometry, and number of surface amine groups) of poly (amidoamine) (PAMAM) dendrimers, on their permeability across Caco-2 cell monolayers. The permeability of a series of PAMAM dendrimers, generations 0-4 (G0-G4), was investigated across Caco-2 cell monolayers in...

We describe the successful application of a new method to estimate permeability and permeability anisotropy from transient measurements of pressure acquired with a wireline straddle-packer formation tester. Unlike standard algorithms used for the interpretation of formation-tester measurements, the method developed in this paper incorporates the physics of two-phase immiscible flow as well as t...

Aquaporin 6 (AQP6) is unique among mammalian AQPs in being an anion channel with negligible water permeability. However, the point mutation Asn60Gly converts AQP6 from an anion channel into a water channel. In the present study of human AQP5, we mutated Leu51 (corresponding to residue 61 in AQP6), the side chain of which faces the central pore. We evaluated function in Xenopus oocytes by two-el...