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  • tight junctions
  • Vessels of the BBB are composed of specialized endothelial cells that lack fenestration (pores that allow rapid exchange of molecules between vessels and tissue), have few pinocytic vesicles to minimize uptake of extracellular substances, and have extensive tight junctions that severely restrict cell permeability. (rndsystems.com)
  • Systemic
  • Limited permeability restricts movement of substances from the systemic circulation to the brain which buffers the brain from rapid changes in ionic or metabolic conditions. (rndsystems.com)
  • regulate
  • These cells, along with the extracellular matrix, function as a neurovascular unit to regulate BBB permeability and maintain the integrity and function of the central nervous system. (rndsystems.com)
  • vascular
  • BBB permeability is influenced by neurons, the extracellular matrix, and non-neuronal cells including astrocytes, pericytes, and vascular endothelial cells. (rndsystems.com)
  • porosity
  • The permeability of a medium is related to the porosity, but also to the shapes of the pores in the medium and their level of connectedness. (wikipedia.org)
  • A rock with 25% porosity and a permeability of 1 md will not yield a significant flow of water. (wikipedia.org)
  • Permeability is influenced by the porosity of the substance (the fractional void volume), the degree of occlusion of the space through which the fluid flows, the diameter of the space through which the fluid flows, the viscosity of the fluid, and the surface interactions between the fluid and the walls of the vessel. (scielo.br)
  • The proposed method in this study combines core data (permeability) from 32 cored wells with identifiable reservoir rock types (RRTs) and log data (porosity and Swi) to develop drainage logderived capillary pressure (Pc) based on rock quality index (RQI) and then calculate J-function for each RRT which was used to calculate the initial water saturation in the reservoir. (scribd.com)
  • It was difficult to differentiate between the Mercury injection capillary curves (MIPCs) for a given RRT based of porosity and/or permeability ranges. (scribd.com)
  • Develop log-derived Pcs or J-functions using the available data (log-porosity, log-Swi, core permeability, and log-derived RRTs) to calculate the initial water saturation distribution in the entire reservoir. (scribd.com)
  • porosity and permeability.com Check the quality of regression by plotting the right hand side (RHS) of equation 4 versus the LHS (see Figure 1). (scribd.com)
  • Oxygen
  • Oxygen permeability (OP) is a parameter of a contact lens that expresses the ability of the lens to let oxygen reach the eye by diffusion. (wikipedia.org)
  • The earliest models of soft contact lenses, based on hydrogel material, had a level of oxygen permeability of around 6-8 Dk/t. (wikipedia.org)
  • These days, typical values of oxygen permeability for hydrogel contact lenses range from 25 to 50. (wikipedia.org)
  • While those numbers are typical of hydrogel contact lenses, many contact lenses are made of silicone hydrogel, which has a much higher oxygen permeability. (wikipedia.org)
  • These values are more that twice the values of oxygen permeability for hydrogel materials. (wikipedia.org)
  • New to this edition are 92 resin chapters containing textual summary information including: category, general description, processing methods, applications, and general permeability considerations for water vapor, oxygen, and other gases including aroma and flavor. (elsevier.com)
  • and an inert porous filler optionally having a surface modifying agent coated thereon, the inert porous filler being present in an amount effective to reduce the ratio of the carbon dioxide permeability to the oxygen permeability of the film, and wherein the filler has a particle size greater than the intrinsic film thickness of the film forming polymer. (google.es)
  • ratio
  • Relative permeability, denoted by the symbol μ r {\displaystyle \mu _{\mathrm {r} }} , is the ratio of the permeability of a specific medium to the permeability of free space µ0: μ r = μ μ 0 , {\displaystyle \mu _{\mathrm {r} }={\frac {\mu }{\mu _{0}}},} where μ 0 = {\displaystyle \mu _{0}=} 4π × 10−7 N·A−2 is the (exact) magnetic permeability of free space. (wikipedia.org)
  • Thus the required pressure/flow ratio can be obtained from the ratio of the two manometer readings, and when fed into the Carman equation, yields an "absolute" value of the air permeability surface area. (wikipedia.org)
  • b) a modified porous filler selected from the group consisting of alumina, silica, pumice and scoria, having a surface modifying agent coated thereon in an amount such that the CO 2 /O 2 permeability ratio is reduced to approximately 0.5 to 5. (google.es)
  • As a result, the relative permeability depends not only on saturation, but also on the capillary number, viscosity ratio, wettability of the solid wall, pore geometry, and the initial configuration. (ubc.ca)
  • A number of factors affect the permeability of soils, from particle size, impurities in the water, void ratio, the degree of saturation, and adsorbed water, to entrapped air and organic material. (wikipedia.org)
  • viscous
  • Based on the Hagen-Poiseuille equation for viscous flow in a pipe, permeability can be expressed as: κ I = C ⋅ d 2 {\displaystyle {\kappa }_{I}=C\cdot d^{2}} where: κ I {\displaystyle {\kappa }_{I}} is the intrinsic permeability [lengthC {\displaystyle C} is a dimensionless constant that is related to the configuration of the flow-paths d {\displaystyle d} is the average, or effective pore diameter [length]. (wikipedia.org)
  • reservoir rock
  • Gas permeability of reservoir rock and source rock is important in petroleum engineering, when considering the optimal extraction of shale gas, tight gas, or coalbed methane. (wikipedia.org)
  • optimization
  • Actually the optimization behaviour of packaging permeability is of crucial importance, in order to extend the food shelf-life and to reach the best engineering solution. (hindawi.com)
  • relates
  • The present invention relates to controlled permeability film compositions for use in controlled atmosphere packaging and to the protective packaging of sensitive produce therewith. (google.es)
  • methods
  • The properties and methods by which some of these tracers are used to study BBB permeability to proteins and ions in pathologic states will be described. (springer.com)
  • vessels
  • Scanning Electron Microscopy images showed that the distribution and obstruction in the vessels could be correlated with observed permeability properties. (scielo.br)
  • Tracers provide information about the permeability status of vessels immediately before sacrifice. (springer.com)
  • measurements
  • The everted gut sac technique uses a more relevant sample size, and in vivo permeability measurements using Co-EDTA or lactulose are much more practical. (wur.nl)
  • 1988
  • In the stability formula developed of VAN DER MEER this effect is represented by the term Notional Permeability with symbol P. A more open, or permeable, structure underneath the armour layer has the ability to dissipate more wave energy and therefore requires less weight of the armour layer. (tudelft.nl)
  • permeable
  • As for permeability, it suggests that residential areas should be permeable enough to allow movement in all directions but no more. (wikipedia.org)
  • Filtered permeability is the concept, supported by organisations such as Sustrans, that networks for walking and cycling should be more permeable than the road network for motor vehicles. (wikipedia.org)
  • water
  • Liquid permeability was tested using an emulsion of Neen oil and a control of distillated water. (scielo.br)
  • The permeability of air and water through the sapwood of Eucalyptus grandis was greater than that through the sapwood of Eucalyptus citriodora . (scielo.br)
  • The permeability is reduced due to the presence of air which causes a blockage to the passage of water. (wikipedia.org)
  • However, the permeability change is not large and can mostly be accounted for by water viscosity changes. (mdpi.com)