The integrated response to hypotonic NaCl solutions (100, 50, 25, and 0 mM NaCl) in proximal duodenum of anesthetized rats was examined. Luminal alkalinization, fluid flux, duodenal contractions, blood-to-lumen clearance of 51Cr-labeled EDTA (mucosal permeability), and perfusate osmolality were studied in the absence and presence of the cyclooxygenase inhibitor indomethacin. In response to hypo...

PURPOSE A culture model was used to examine the development of tight junctions in the retinal pigment epithelium (RPE). METHODS Chick RPE was isolated on embryonic day 7 (E7), E10 or E14 and cultured on laminin-coated filters. Barrier properties were stimulated with E14 retinal conditioned medium. Morphology was characterized by confocal microscopy. Permeability was determined by measuring th...

AIM Maintenance of the blood and extracellular volume requires tight control of endothelial macromolecule permeability, which is regulated by cAMP signalling. This study probes the role of the cAMP mediators rap guanine nucleotide exchange factor 3 and 4 (Epac1 and Epac2) for in vivo control of microvascular macromolecule permeability under basal conditions. METHODS Epac1-/- and Epac2-/- C57B...

textile wastewaters due to the toxic effects of dyestuffs and other organic compounds and their stability toward light and oxidizing agents have led to an environmental problem. several treatment methods for dye removal have been investigated. membrane process is one of the simplest and most effective methods for dye removal from industrial wastewaters. electrospun nanofibrous membranes have hi...

A method is proposed to measure the water permeability of membrane channels by means of molecular dynamics simulations. By applying a constant force to the bulk water molecules and a counter force on the complementary system, a hydrostatic pressure difference across the membrane can be established, producing a net directional water flow. The hydraulic or osmotic permeability can then be determi...

The effect of methylprednisolone (2 mg/kg per day given parenterally for 3 doses, 2 wk or 12 wk) on the permeability of mammalian gastric mucosa to hydrogen ion (H(+)) was examined with denervated fundic pouches in dogs with antrectomies. Transmucosal electric potential difference (PD) and net fluxes of H(+) and Na(+) were determined for luminal [H(+)] from 20 to 160 mM and [Na(+)] from 1 to 14...

Rat proximal convoluted tubules were perfused in vivo to examine the active and passive components of chloride absorption. Chloride flux was a linear function of the transepithelial electrochemical driving force, yielding a permeability coefficient of 20.6 X 10(-5) cm/s. In the absence of an electrochemical driving force, chloride absorption persisted at the rate of 131 peq/mm X min, thus demon...

Our previous description of solute drag on a synthetic membrane has been extended to include the solutes mannitol, sucrose, raffinose, inulin, and dextran. Labeled and nonlabeled forms of these solutes were used in pairs to quantitate solute flux interaction. Three membranes with pore sizes of 350, 80, and 20 A, respectively, have been utilized. It is shown that solute flux interaction occurs w...

This paper proposes a model for the electromagnetic performance of dual air-gap liquid-cooled eddy current retarder (DAL-ECR) considering transient permeability. First, structure and working principle DAL-ECR are introduced. Next, analysis static flux density leakage end effect is established based on piecewise function method magnetic equivalent circuit (MEC). Then, skin field in retarder, an ...

Generally, the bridges or buildings cannot be constructed on a refuse landfill, since the special chemical compositions and microorganisms in landfill will impose adverse effects on the concrete foundations. Especially, the impacts on their durability are still unknown. The purpose of this paper is to get the corrosive features of a refuse landfill to give suggestions for the durability design ...