Protons and sodium ions are the only used coupling ions in energy transduction in Bacteria and Archaea. At their growth temperature, the permeability of the cytoplasmic membrane of thermophilic bacteria to protons is high as compared to sodium ions. In some thermophiles, therefore, sodium is the sole energy coupling ion. Comparison of the protonand sodium permeability of the membranes of variet...

This study sought to determine whether the permeability related parameter K(trans), derived from computed tomography perfusion (CTP) imaging, can predict hemorrhagic transformation (HT) in patients with acute ischemic stroke who receive intra-arterial thrombolysis. Data from patients meeting the criterion were examined. CTP was performed and K(trans) maps were used to assess the permeability va...

Extremely low permeability due to nano-scale pores is a distinctive feature of gas transport in a shale matrix. The permeability of shale depends on pore pressure, porosity, pore throat size and gas type. The pore network model is a practical way to explain the macro flow behavior of porous media from a microscopic point of view. In this research, gas flow in a shale matrix is simulated using a...

productivity of an oil well is an important parameter in any oil field development. low production rate of the wells, impose more production wells drilling which directly jeopardizes the economical feasibility of the project. oil production rate in some of the wells is very low due to low permeability of the reservoir rock. several practice like hydraulic fracturing and acid fracturing is very ...

We studied proteoglycan distribution in areas of spontaneously occurring high and low permeability by TEM examination of ruthenium red-stained sections of the aortic arch of normolipemic and hyperlipemic pigs. We noted granules of two sizes: those smaller than 20 nm contained heparan sulphate, and those from 20 to 50 nm in size contained chondroitin or dermatan sulphate. In the aortas of pigs f...

En face autoradiography of the endothelium was used to quantify the distribution, area, and permeability of sites with enhanced permeability to 125I-low-density lipoprotein (125I-LDL) around the intercostal and celiac arteries and at the iliac bifurcation of normal rabbit aortas. The density of such sites was highest in the upper thoracic aorta and around the celiac and superior mesenteric bran...

Three Ca(2+)-dependent procedures known to increase cation permeability of red blood cell membranes were tested with Cd2+ ions which equal Ca2+ ions both in their charge and the crystal radius, 1. Increase of non-selective permeability for monovalent cations by incubating the red cells in a Ca(2+)-free sucrose medium. Addition of Cd2+ to the suspension of leaky cells failed to restore the initi...

We investigate the effect of different saturation histories relevant to various oil displacement processes (including secondary and tertiary gas injections) on three-phase gas/oil/brine relative permeabilities of water-wet sandstone. It is found that three-phase water (wetting phase) relative permeability is primarily a function of water saturation and shows no dependency upon saturation histor...