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Permeability Measurements (permeability + measurement)
Selected AbstractsPermeability measurements in an individually perfused capillary: the ,squid axon' of the microcirculationEXPERIMENTAL PHYSIOLOGY, Issue 4 2008Fitz-Roy E. Curry No abstract is available for this article. [source] Water-repellent finishing of cotton fabrics by ultraviolet curingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008F. Ferrero Abstract Cotton fabrics were water-repellent-finished by radical ultraviolet curing of silicone and urethane acrylates with different formulations. The fabrics were impregnated with undiluted resins and with toluene solutions or water emulsions. Moreover, cationic ultraviolet-curable systems were also investigated, such as an epoxy-functional polysiloxane and mixtures of an epoxy resin with hydroxyl-containing silicone additives. The gel content and polymerization yield were considered for the ultraviolet-curing process evaluation. Water-resistance properties were determined in terms of the contact angle, wettability, moisture adsorption, and water vapor permeability measurements, whereas the morphology and surface composition of treated fabrics were examined with scanning electron microscopy and energy-dispersive X-ray analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Quantitative characterization of sphere-templated porous biomaterialsAICHE JOURNAL, Issue 4 2005A. J. Marshall Abstract Three-dimensional (3-D) porous hydrogels were fabricated by polymerizing 2-hydroxyethyl methacrylate around templates of random close-packed poly(methyl methacrylate) microspheres with nominal diameter of 5 or 15 ,m. The templates were leached out to create networks of interconnected spherical pores. Applications for sphere-templated porous biomaterials include scaffolds for tissue engineering and spatial control of wound healing. This study describes an approach to characterizing pore structure and predicting permeability of sphere-templated porous hydrogels. The materials were embedded in resin, and 1-,m-plane sections were digitally analyzed with fluorescence microscopy. The porosity and pore size distribution were determined from stereological interpretation, and we present novel techniques for obtaining the pore throat size distribution, the number of pore throats per pore, and the tortuosity. A simple apparatus is also introduced for measurement of the hydraulic permeability. Permeability predictions based on quantitative microscopy measurements and on stereology were found to agree closely with permeability measurements. The aptness of the Kozeny equation for spherically pored materials is also investigated. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] PERMEABILITY ANISOTROPY DISTRIBUTIONS IN AN UPPER JURASSIC CARBONATE RESERVOIR, EASTERN SAUDI ARABIAJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2007A. Sahin Most classical reservoir engineering concepts are based on homogeneous reservoirs despite the fact that homogeneous reservoirs are the exception rather than the rule. This is especially true of carbonate reservoirs in the Middle East which are known to be highly heterogeneous. The realistic petrophysical characterization of these kinds of reservoirs is not an easy task and must include the study of directional variations of permeability. Such variation can be incorporated into engineering calculations as the square root of the ratio of horizontal to vertical permeability, a parameter known as the anisotropy ratio. This paper addresses the distribution of anisotropy ratio values in an Upper Jurassic carbonate reservoir in the Eastern Province of Saudi Arabia. Based on whole core data from a number of vertical wells, statistical distributions of horizontal and vertical permeability measurements as well as anisotropy ratios were determined. The distributions of both permeability measurements and anisotropy ratios have similar patterns characterized by considerable positive skewness. The coefficients of variation for these distributions are relatively high, indicating their very heterogeneous nature. Comparison of plots of anisotropy ratios against depth for the wells and the corresponding core permeability values indicate that reservoir intervals with lower vertical permeability yield consistently higher ratios with considerable fluctuations. These intervals are represented by lower porosity mud-rich and/or mud-rich/granular facies. Granular facies, on the other hand, yielded considerably lower ratios without significant fluctuations. [source] Cytotoxicity evaluation of enzyme inhibitors and absorption enhancers in Caco-2 cells for oral delivery of salmon calcitoninJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2004Rakhi B. Shah Abstract The usefulness of enzyme inhibitors and absorption enhancers with least mucosal cell cytotoxicity was evaluated on Caco-2 cell monolayers. The temporal cytotoxicity of several protease inhibitors at 500 ,g/mL (e.g., turkey and chicken ovomucoids, aprotinin, and Protease Inhibitor Cocktail) and absorption enhancers [e.g., cholate (3%), glycocholate (3%), glycosursodeoxycholate (3%), ethylenediaminetetraacetic acid (EDTA, 0.1%), hydroxypropyl-,-cyclodextrin (HP-,-CD, 5%), hydroxypropyl-,-cylcodextrin (HP-,-CD, 5%), ,-cylcodextrin (,-CD, 5%), tetradecyl-,- D -maltoside (0.25%), octylglucoside (0.25%), citric acid (10%), glycyrrhetinic acid (0.34 mM), and Tween-80® (0.1%)] was measured by monitoring their effect on Caco-2 cell viability. Cell viability was measured by mannitol permeability measurements, transepithelial electrical resistance (TEER) measurements, DNA-propidium iodide staining assay, and WST-1 assay (tetrazolium salt based assay). Sodium dodecyl sulfate (0.1%), a potent surfactant, was used as a positive control. Chicken and turkey ovomucoids were nontoxic to cells as evaluated by all the methods used. Aprotinin decreased the TEER, whereas plasma membrane damage was seen with Protease Inhibitor Cocktail after a 24-h period. With respect to the absorption enhancers, the toxicity increased directly as a result of an increase in the time of incubation. The enhancers EDTA and HP-,-CD can be used safely for a short period of time, whereas glycosursodeoxycholate, glycyrrhetinic acid, octylglucoside, HP-,-CD, and ,-CD can be used for a longer period. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93: 1070,1082, 2004 [source] Assessment and prevention of gastrointestinal toxicity of non-steroidal anti-inflammatory drugsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2006Majella E. Lane Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for analgesic, anti-inflammatory and, in the case of aspirin, for anti-thrombotic actions. The serious gastrointestinal side-effects associated with these drugs are of concern and pose a significant obstacle to their use. This review discusses the pathogenic mechanisms by which the conventional acidic NSAIDs induce gastrointestinal toxicity, with particular emphasis on non-prostaglandin effects. Methods of assessment of NSAID-induced enteropathy are reviewed, with particular emphasis on the use of functional measurement of NSAID-induced changes in the gastrointestinal tract. The advances in our knowledge of the pathogenesis of these effects have resulted in the development of a range of novel NSAIDs. Where functional assessment of the effects of NSAIDs has been employed, it appears to be more useful as an indicator of early-stage changes rather than a predictor of the effects of long-term NSAID exposure. Successful pharmaceutical strategies now offer considerable promise for reducing the severity of NSAID damage to the gastrointestinal tract. The utility of intestinal permeability measurements for selection and assessment of these strategies is discussed. [source] | ||||||||||