TY - GEN. T1 - Permeability measurement methods in porous media. T2 - 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008. AU - Sharma, Sanjay. AU - Siginer, Dennis A.. PY - 2009/9/15. Y1 - 2009/9/15. N2 - Accurate measurement of Permeability is critical for fluid flow modeling in porous media. Various experimental methods have been devised that measure permeability as a porous material property. These experiments are based most commonly on Darcys law. Liquid flow and gas flow methods of permeability measurement for in-plane and transverse directions are detailed. Issues related to these methods are discussed. Some associated permeability models are discussed. Alternative methods of permeability determination based on cross transport phenomenon are presented.. AB - Accurate measurement of Permeability is critical for fluid flow modeling in porous media. Various experimental methods have been devised that measure permeability as a porous material property. These ...
TY - JOUR. T1 - Effect of aging and caloric restriction on intestinal permeability. AU - Ma, Thomas Y.. AU - Hollander, Daniel. AU - Dadufalza, Violeta. AU - Krugliak, Pavel. PY - 1992. Y1 - 1992. N2 - Intestinal permeability is increased in several disorders such as Crohns disease or rheumatoid arthritis. Since aging leads to alteration of many biological functions, the effect of aging on intestinal permeability was studied by measuring the intestinal permeability in aging rats gavaged with different size permeability probes- mannitol, polyethylene glycol (PEG) 400, and inulin. In rats fed with control diet, there was a significant increase in intestinal permeability to medium size probes PEG 400 (14.8 ± 0.4 and 21.0 ± 1.1% at 3 and 28 months respectively, p , .01) and mannitol (3.41 ± 0.4 and 5.3 ± 0.5% at 3 and 28 months, respectively, p , .01). Intestinal permeability of the large macromolecule inulin did not change (0.42 ± 0.03 and 0.38 ± 0.02% at 3 and 28 months, respectively) with ...
The design of new austenitic alloys based on the Fe-Ni-Cr system requires knowledge of their oxygen permeability. Data are available for pure Fe and Ni but not for Fe-Ni alloys. Wagners model for internal oxidation is used to evaluate the oxygen permeability in Fe-Ni alloys. Internal oxidation of Fe-Ni-Cr alloys carried out at 1150 and 1100 °C in Rhines packs and H2/H2O mixtures is described. Internal oxidation produces zones of FeCr2O4 and Cr2O3 precipitates, according to parabolic kinetics. Permeabilities are deduced taking into account interfacial diffusion contributions. Oxygen permeability decreases with nickel addition in a non-ideal way, and oxygen permeability in nickel-rich alloys is independent of the studied environments. However, the oxygen permeability in iron at the highest temperature studied is increased in H2/H2O.
Increased gut permeability or leaky gut has been an important feature of quite a lot of autism research in 2013. Referencing issues with the delicate barrier which separates the contents of the gastrointestinal (GI) tract from the wider body environment, elevated gut permeability as being a feature in some cases of autism is slowly moving out of the research fringes into something altogether more mainstream.. This statement is based on both investigations of people with autism and also recent results from two quite well-known mouse models of autism also potentially presenting with permeability issues.. The paper by Dalton and colleagues* further adds to the conversation about issues with gut permeability and autism observing that 8% of children with autism in their cohort presented with gut permeability measures outside of recognised reference ranges. Further, that 6% of children with special educational needs (SEN) (but not autism) also presented with potential gut permeability issues ...
TY - JOUR. T1 - Intestinal permeability increases with the severity of abdominal trauma: a comparison between gas liquid chromatographic and enzymatic method. AU - Gasbarrini, Giovanni Battista. AU - Mingrone, Geltrude. AU - Liverani, E. AU - Silveri, Ng. PY - 2000. Y1 - 2000. N2 - Increased intestinal permeability was found in humans after multiple trauma, burn injury and major vascular surgery. However, no data are reported regarding possible correlation between trauma and intestinal permeability degree. This study was undertaken to compare gas-liquid chromatographic and enzymatic method for the evaluation of intestinal permeability impairment in patients after severe abdominal trauma.. AB - Increased intestinal permeability was found in humans after multiple trauma, burn injury and major vascular surgery. However, no data are reported regarding possible correlation between trauma and intestinal permeability degree. This study was undertaken to compare gas-liquid chromatographic and enzymatic ...
TY - GEN. T1 - Permeability measurement of orthotropic fibers under an acoustic force field. AU - Sharma, Sanjay. AU - Siginer, Dennis. PY - 2009/12/1. Y1 - 2009/12/1. N2 - Using the validated acoustic method of determining physical properties of porous materials, acoustical properties of the orthotropic medium is used to predict longitudinal and transverse permeability. Measurement of samples in the impedance tube is conducted using ASTM E 1050 for a frequency range of 50 Hz to 6.4 KHz. The acoustical method is shown to compute longitudinal and transverse permeability for various porosity levels. The method describes permeability prediction for carbon, glass and hybrid lay ups. Longitudinal permeability calculated from the absorption coefficient of sized and unsized fibers is found to be the same in contrast to the flow methods.. AB - Using the validated acoustic method of determining physical properties of porous materials, acoustical properties of the orthotropic medium is used to predict ...
TY - CHAP. T1 - THREE DIMENSIONAL PERMEABILITY MEASUREMENTS.. AU - Morita, Nobuo. AU - Gray, K. E.. PY - 1980. Y1 - 1980. N2 - Procedures are provided to calculate principal permeabilities and directions from data obtained with a whole core type permeameter which has radial and axial flow measurement capabilities with two openings attached to cylindrical curved surface. The conventional plug method to determine anisotropic permeability was also modified to improve its accuracy; plug number and sample spacing were rigorously designed using error sensitivity numbers. To check the validity of the apparatus, experiments were run using anisotropic Berea sandstone.. AB - Procedures are provided to calculate principal permeabilities and directions from data obtained with a whole core type permeameter which has radial and axial flow measurement capabilities with two openings attached to cylindrical curved surface. The conventional plug method to determine anisotropic permeability was also modified to ...
The Caco-2 permeability assay provides a measure of the permeability of a test compound across the intestinal barrier and its potential for interactions with drug transporters. We provide permeability assays for small molecule formulations such as pharmaceuticals, industrial chemicals and consumer products.
Although polymorphonuclear leukocytes (PMNs) can migrate through every epithelium in the body regardless of its permeability, very little is known about the effect of epithelial permeability on PMN migration and the effect of emigrating PMNs on the permeability of the epithelium. In an in vitro model system of transepithelial migration, human PMNs were stimulated by 0.1 micrometer fMet-Leu-Phe to traverse confluent, polarized canine kidney epithelial monolayers of varying permeabilities. Epithelial permeability was determined by both conductance measurement and horseradish peroxidase (HRP) tracer studies. As epithelial permeability increased, the number of PMN invasion sites as well as the number of PMNs that traversed the monolayer increased. The effect of PMN migration on epithelial permeability was examined using the ultrastructural tracers HRP and lanthanum nitrate. PMNs traversing the monolayer made close cell-to-cell contacts with other invading PMNs and with adjacent epithelial ...
The relative permeability is the ratio … Permeability is a property that quantifies the ability to flow or transmit fluids through a rock when a single fluid is present in pore space.5 Absolute permeability quantifies this relationship when the fluid being transmitted is water.5 The use of core analysis was applied during this study At high water saturations, the oil exists as disconnected droplets occupying the centers of pores. Air permeability at different overburden pressures [131]. Relative permeability is defined as a ration of effective permeability to an absolute permeability of rock. . Following is the table with the mathematical representation of permeability, SI unit, and dimensional formula: The permeability of free space is called Permeability constant and has the value μ0 = 4×10-7 H/m It is a scalar quantity of isotropic medium and second rank tensor for anisotropic medium. In studies [129, 130] with very low permeability sandstones, liquid per-meabilities were found to be less ...
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TY - PAT. T1 - Compositions and Methods for Enhancing Paracellular Permeability across Epithelial and Endothelial Barriers. AU - Thakker,Dhiren R.. AU - Ward,Peter D.. N1 - Status: published applicationnumber: 09/974,519 usclass: 514/75 ; 514/642; 514/76; 514/946 applicationnumber: 09/974,519. PY - 1800. Y1 - 1800. N2 - Compositions and methods for enhancing paracellular permeability at an absorption site in a subject are disclosed. The method includes: (a) administering an effective amount of a phospholipase C inhibitor to a subject at a time in which enhanced paracellular permeability is desired; and (b) enhancing paracellular permeability in the subject at the absorption site through the administering of the effective amount of the phospholipase C inhibitor. The disclosed compositions and methods provide enhanced absorption of a hydrophilic drug in a subject.. AB - Compositions and methods for enhancing paracellular permeability at an absorption site in a subject are disclosed. The method ...
TY - GEN. T1 - Combined effects of laminae characteristics and matrix-fracture equilibrium hysteresis on permeability evolution of fractured sorbing rocks. AU - Zeng, Jie. AU - Liu, Jishan. AU - Li, Wai. AU - Leong, Yee Kwong. AU - Elsworth, Derek. AU - Guo, Jianchun. N1 - Funding Information: This work is supported by the Australian Research Council under Grant DP200101293, UWA China Scholarships, and the China Scholarship Council (CSC No. 201707970011).. PY - 2020. Y1 - 2020. N2 - Permeability is a critical property of fractured sorbing rocks, such as shale and coal, as it controls the gas transport. However, two distinctive features are commonly not simultaneously included in existing permeability models. One is the stratified feature which has been evidenced by an appreciable number of laboratory investigations. The second one is matrix-fracture non-equilibrium induced matrix-fracture interactions during permeability measurement or field operations. The goal of this research is to uncover ...
Acceptor-type doping of perovskite-type La1-x,SrxGa0.80-y,MgyM0.20O3-delta (x = 0-0.20, y = 0.15-0.20, M = Fe, Co, Ni) leads to significant enhancement of the oxygen permeability due to increasing oxygen vacancy concentration and, thus, ionic conductivity. The increase in strontium and magnesium content is accompanied, however, with increasing role of the surface exchange kinetics as a permeation-limiting factor. At temperatures below 1223 K, the oxygen permeation (OP) fluxes through dense La(Sr)Ga(Mg,M)O3-delta membranes with the thickness less than 1.5 mm are mainly limited by the exchange rate at membrane/gas boundaries. For transition metal-containing La(Sr)Ga(Mg)O3-delta (LSGM) ceramics, the oxygen transport increases in the sequence Co < Fe < Ni. The highest permeation is observed for La0.90Sr0.10Ga0.65Mg0.15Ni0.20O3-delta perovskite membranes, which exhibit level of the oxygen permeability similar to that of La(Sr)Fe(Co)O3-delta and La2NiO4-based solid solutions. The average thermal expansion
Near-surface sediments play an important role in governing the movement of water and contaminants from the land surface through the vadose zone to groundwater. Generally, low permeability surficial soils restrict water flow through the vadose zone and form a natural protective barrier to migration of surface applied contaminants. These types of fine-grained soils commonly contain macropores, such as fractures, animal burrows, and root holes, that have been identified as preferential flow pathways in the subsurface. Accordingly, macropores have the potential to influence groundwater recharge rates and compromise the protective capacity of surficial soils, particularly where the overburden is thin and aquifers are close to the surface. Partially saturated flow and transport in these environments is inherently complex and not well understood. The objective of this thesis was to examine preferential flow processes and the associated movement of contaminants in macroporous, low permeability soils. ...
Recovery of hydrocarbon gas in micro-Darcy rock is now becoming more common-place for gas producers. As part of the reservoir characterization associated with these systems, it is required to understand parameters such as the total porosity and permeability of the system, but also the initial water saturation and the effective gas permeability at this connate water saturation. This is still under the realm of what is termed routine core analysis, but in these tight formations it is imperative to understand that these tests are actually very non-routine by nature. Current work presents a case study of core analysis that was run on plugs from a tight gas producing formation, and illustrates some of the pitfalls and corrections associated with measurements of this low permeability rock. The case study combines low field NMR measurements with core flooding measurements of porosity and permeability. Cores are initially tested at their connate water saturations: NMR measures the initial water ...
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permeability curve shape. Other methods for estimation of relative permeability curves include derivation from simulation history-matching, and production data analysis. Both of these methods will yield pseudo relative permeability curves whose shapes could be affected by several dynamic CBM reservoir and operating characteristics.. The purpose of the current work is to perform a systematic investigation of the controls on CBM relative permeability curve shape, including non-static fracture permeability and porosity, multi-layer effects and transient flow. To derive the relative permeability curves, effective permeability to gas and water are obtained from flow equations using a modified version of the approach described by Clarkson et al. (2007). Simulated cases are analyzed so that derived and input curves may be compared allowing for investigation of CBM reservoir properties on curve-shape. One set of relative permeability curves that were input into the simulator were derived from pore-scale ...
TY - GEN. T1 - Hydraulic permeability and electro-kinetic properties of charged-hydrated tissues during permeation. AU - Gu, W. Y.. AU - Lai, W. M.. AU - Mow, V. C.. PY - 1992/12/1. Y1 - 1992/12/1. N2 - The functional dependences of hydraulic permeability and electrokinetic properties on the composition and material properties of charged hydrated tissues (e.g., articular cartilage) during a one dimensional steady permeation experiment have been derived using the recently developed triphasic theory [Lai et al., 1991]. The results showed that these properties vary within the tissue due to physical interactions between the flowing fluid (including the flowing ions) and the charged porous-permeable solid matrix. Fundamental relationships governing these effects depend on the tissue water content, fixed charge density, solid matrix elastic moduli (i.e., strain-dependent permeability) and the frictional coefficients between the porous-permeable solid matrix and the interstitial fluid. In addition, a ...
Among the most critical factors for geological CO2 storage site screening, selection and operation is effective simulation of multiphase flow and transport. Relative permeability is probably the greatest source of potential uncertainty in multiphase flow simulation, second only to intrinsic permeability heterogeneity. The specific relative permeability relationship assigned greatly impacts forecasts of CO2 trapping mechanisms, phase behavior, and long-term plume movement. A primary goal of this study is to evaluate the impacts and implications on CO2-EOR model forecasts of different methods of assigning relative permeability relationships.. We applied a novel approach to assigning relative permeability relationships in numerical models. In previous research, most models assign relative permeability functions on the basis of geologic formation or rock type. In this study, we assign and calibrate relative permeability by hydrostratigraphic units, extending the seminal work of Maxey (1964) to ...
Filter permeability is a significant term used to measure the endothelial permeability to fluid. There exist permeable sheath in the walls of the filter that allows the fluid (oil, fuel, water) to get in and out. Amongst the numerous methods of measuring micro vascular permeability to fluids infiltration, filter permeability aces.. What Is The Need For Filter Permeability?. In simple language, filtering the solid particles and microorganisms from the fluid by depositing them on the filters septum is what filter permeability does. A study of the correlation of the air permeability of the filter paper and rate of filtration is studied to get the active relationship and speed of the filtration. Through filter permeability process, the resistance is understood. Lower the permeability represents a high resistance and higher the permeability states a low resistance.. How Is Filter Permeability Expressed?. ...
A methodology to test the possible deviations of fracture relative permeabilities from straight-line relationship with saturation is discussed. It is shown that with matrix relative permeability data known, it is possible to obtain fracture relative permeabilities by history matching experimental data with double porosity numerical models output. Rather than linear saturation dependence, fracture relative permeability is a power law function of the corresponding phase saturation. The impact of several important parameters like double porosity formulation, capillary pressure and shape factor is discussed. It has been found that double porosity formulations (other than the double permeability model) could represent the flow in a fractured medium. (C) 2001 Published by Elsevier Science B.V ...
Read A Quantitative Model for the Dependence of Solute Permeability on Peptide and Cholesterol Content in Biomembranes, The Journal of Membrane Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
In vivo and ex vivo studies with whole vessels demonstrated that the endothelium comprises the major permeability barrier in the blood vessel wall. As a lining between the blood and the underlying tissue, the endothelium is exposed to biochemical components of the blood and wall shear stress. The endothelium responds to these biochemical and mechanical agonists both metabolically and morphologically. Using a model system consisting of human umbilical vein endothelial cells cultured on a permeable polycarbonate membrane, the permeability barrier function of endothelial monolayers was characterized quantitatively by determination of permeability coefficients. The effect of biochemical agonists and wall shear stress on permeability was assessed by the extent to which the agonists modulated the baseline permeability coefficient. Permeability increased nearly 10-fold over baseline values in the presence of 0.1 U/ml thrombin. Using altered forms of thrombin, it was shown that both proteolytic activity ...
Phyllite clays are applied as a layer on a surface to be waterproofed and subsequently compacted. For this purpose, phyllite clays deposits can be grouped by their chemical and mineralogical characteristics, and these characteristics can be connected with their properties, mainly permeability, in order to select those deposits with the lowest permeability values. Several deposits of phyllite clays in the provinces of Almería and Granada (SE Spain) have been studied. The results of applying a multivariate statistical analysis (MVA) to the chemical data analysed from 52 samples determined by XRF, mineralogical analysis by XRD and permeability are reported. Permeability, a characteristic physical property of phyllite clays, was calculated using the results for experimental nitrogen gas adsorption and nitrogen adsorption-desorption permeability dependence. According to the results, permeability values differentiated two groups, i.e. group 1 and group 2, with two subgroups in the latter. The ...
The objective of this research is to develop and test a new concept for predicting permeability from routine rock properties. First, we develop a model predicting permeability as a function of capillary pressure. Our model, which is based on the work by Purcell, Burdine and Wyllie and Gardner models, is given by: (Equation 1 - See PDF) Combining the previous equation and the Brooks and Corey model for capillary pressure, we obtain: (Equation 2 - See PDF) The correlation given by this equation could yield permeability from capillary pressure (and vice-versa). This model also has potential extensions to relative permeability (i.e., the Brooks and Corey relative permeability functions) - which should make correlations based on porosity, permeability, and irreducible saturation general tools for reservoir engineering problems where relative permeability data are not available. Our study is validated with a large range/variety of core samples in order to provide a representative data sample over ...
The novel findings in this study are that an increase in gut apoptotic activity occurs after endotoxin infusion and is associated with increased gut macromolecular permeability and increased pulmonary cytokine expression. In this setting, the cointervention of feeding decreases the extent of apoptotic activity, gut permeability, and pulmonary cytokine expression. In other experimental settings, increased gut apoptosis results in increased gut permeability (38, 39). Further investigations suggest that increased gut permeability increases the systemic inflammatory response and involvement of distant organs (30). Together, our new results and previous observations suggest an important association between gut apoptosis, gut barrier function, and pulmonary inflammation during sepsis. Enteral feeding ameliorates increased gut apoptotic activity, which, we postulate, may be a key step in improving gut barrier function and decreasing inflammation in distant organs during sepsis.. Gut injury in sepsis ...
Introduction Relative permeabilities are factual data necessary to any prediction of reservoir production behavior. One important problem in determining relative permeabilities of porous media to gas is the effect of gas slippage on these determinat
Pelaksanaan hydraulic fracturing umumnya dilakukan pada reservoir yang memiliki karakteristik low permeability dan high skin yang menghasilkan laju produksi kecil. Metode stimulasi ini merupakan salah satu upaya untuk meningkatkan laju alir yang diperkirakan dapat meningkat dari produksi sebelumnya. Apabila dibandingkan pekerjaan hydraulic fracturing pada sumur low permeability dan moderate-high permeability dengan menggunakan persamaan Darcy maka peningkatan laju produksi pada suatu reservoir akan terlihat jelas. Perubahan paradigma dan strategi ini menjadi dasar untuk pelaksanaan pekerjaan hydraulic fracturing di struktur O. Sumur O-31 diproduksikan dari lapisan A yang merupakan formasi batu pasir (sandstone) dengan sementasi karbonat dari formasi Talang Akar. Berdasarkan hasil dari dari data log lapisan ini memiliki h = 6.4 m, K = 200 mD, resistivity = 11-26 ohm.m, Pr = 1266 psi, Sw = 35 %, porositas = 25, K = 20 mD, skin factor = + 4.6, dP = 443 psi. Pekerjaan hydraulic fracturing di sumur O-31
The following investigation focuses on the impact of capillary pressure on estimation of two phases relative permeability curves. Accurate relative permeability is a crucial parameter for evaluating reservoir performance. The unsteady state core flooding tests, which is considered in this study, is mostly used to measure oil-water relative permeabilities. The Johnson ,Bossler and Neumann (JBN) method is the conventional method for estimating relative permeabilities from field core. The limitations in the JBN method create an error in relative permeability curves and make it unrepresentative of a typical core flooding test results. There are always capillary pressure effects taking place during core flood tests. Ignoring of capillary pressure by JBN method will influence the calculation of relative permeability curves and final saturation levels. One dimensional numerical model with uniform initial saturation has been implemented in this study using Eclipse 100 software to understand the ...
The results show that a richer gut microbiota composition, a higher abundance of Faecalibacterium prausnitzii, a higher dietary intake of fibre and n-3 LCPUFA as well as multiple vitamins and minerals were associated with lower serum zonulin concentration, ie. lower intestinal permeability. Serum zonulin concentration correlated with serum endotoxin activity, markers of low grade inflammation and glucose metabolism in early pregnancy, suggesting that intestinal permeability may be of importance in regulating maternal metabolic health. Serum zonulin concentration increased with pregnancy progress. While Bifidobacterium animalis ssp. lactis 420 and n-3 LC-PUFA enhanced intestinal epithelium in vitro, they had no effect on serum zonulin levels during pregnancy ...
In the Part 1 paper (Gawin, et al. 2005) some experimental results concerning micro-structuralrntests, permeability measurements and stress-strain tests of four types of High Performance Concrete, exposed to elevated temperatures (up to 700oC) are presented and discussed. On the basis of these experimental results parameters of the constitutive relationships describing influence of damage and temperature upon material intrinsic permeability at high temperature were determined. In this paper the effects of various formulations of damage-permeability coupling on results of computer simulations are analysed and compared with the results obtained by means of the previously proposed approach, that does not take into account thernthermo-chemical concrete damage directly. Numerical solutions are obtained using the recently developedrnfully coupled model of hygro-thermal and damage phenomena in concrete at elevated temperatures. Highrntemperature effects are considered by means of temperature and ...
CARPENTER HIGH PERMEABILITY 49 is an iron-nickel alloy of high magnetic permeability recommended for magnetic and electrical equipment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating. Filing Code: Fe-25. Producer or source: Carpenter. ...
The aim of my thesis was to test whether an increase in the permeability of the gut is accompanied by an increase in the level of systemic lipopolysaccharides (LPS), also referred to as endotoxin. These two parameters were firstly concurrently determined in healthy women after the treatment with a single dose of aspirin which is thought to temporarily increase the paracellular permeability of the intestine. Gut permeability and the levels of systemic LPS in healthy women were then compared with those in women with Crohns disease (CD) as the latter are thought to have chronically elevated paracellular permeability of the gut. Both groups also ingested a high fat drink which is reported to results in the elevation of systemic LPS. In addition, faecal calprotectin, a biomarker of ongoing inflammation in the gut, and LPS-binding protein (LBP), a proposed indirect biomarker for the exposure to LPS in the systemic circulation, were determined both in healthy women and in those with CD. Data indicated ...
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This paper reports recent findings of a research programme focused on the carbonation and permeability of foamed concrete. The objective is to develop an environmentalfriendly and economical material for sustainable construction on peat. A four-year study showed that the rate of carbonation is related to the permeability, time and density. A water permeability test system has been developed based on ISO/DIS7031 and a draft standard prepared. They are aimed at promoting concrete durability research. It features a dual-test method for the measurement of water permeability with the standard 150 mm test cube prior to the determination of compressive strength. The calibration of the test system is by means of a mature test cube of known water permeability. The test system plays complementary role to the existing methods of assessing durability such as carbonation test and rapid chloride permeability. The test method is non-destructive, convenient and reliable for assessing concrete durability in the ...
Research activities will focus on permeability and impermeability as parameters to analyse changing European borders in an increasingly globalised world. This study will mainly be conducted from an economic perspective. First of all, the research will determine the role of borders in offering solutions to economic crises, either through an increased impermeability of states, or through new approaches to permeability within a changing international order. Secondly, we would like to look at borders via a costs and benefits analysis in order to assess the economic benefits of the dismantling of borders and the economic costs connected with functional borders. Thirdly, the research may ponder upon the permeability and impermeability of electronic frontier; the Internet may cross state borders, providing information globally, or attempts may be made to block this flow and introduce censorship, monitoring of citizens and protectionism. Finally, the research will summarise the practices and perception of the
Hydraulic fracturing of horizontal wells in unconventional reservoirs has become the dominant type of well completion performed in the United States. In very low permeability reservoirs (~.00001-.0001 mD), the wellbore is aligned with the minimum horizontal stress, and the completion includes multiple transverse fractures. These fractures may be placed with either open hole sleeve type completion systems (OHMS), or cased hole plug and perf systems (P-n-P). In slightly higher permeability reservoirs (1 to 10 mD) multiple longitudinal fractures have been found to be preferred to completions with transverse fractures. This study presents an evaluation of gas well productivity for both transverse and longitudinal fractured horizontal wells using CFD simulations. The first part of the work includes an evaluation of one and two transverse fractures, over reservoir permeability of 1, 10 and 100 mD. Results, given as fold of increase, are compared to the single transverse fracture model of Augustine (2011).
The study design includes three test days. During day 1, intestinal permeability at rest will be measured. When a blood samples is taken and urine is collected, subjects will ingest a sugar solution in the fasted state after which urine will be collected for 5 hours. In blood and urine, markers for intestinal permeability will be measured. Day 2 and 3 , the same study procedure will take place after the performance of an acute exercise load. The exercise will include a submaximal ergomtery test at 50% of their Wmax or an activity of daily living (ADL) test. The ADL test exist of a combination of several daily activities ...
Abstract. The intestinal epithelium, the largest interface between the host and environment, regulates fluxes of ions and nutrients and limits host contact with the massive load of luminal antigens. Local protective and tolerogenic immune responses toward luminal content depend on antigen sampling by the gut epithelial layer. Whether, and how exaggerated, the entrance of antigenic macromolecules across the gut epithelium might initiate and/or perpetuate chronic inflammation as well as the respective contribution of paracellular and transcellular permeability remains a matter of debate. To this extent, experimental studies involving the in vivo assessment of intestinal permeability using small inert molecules do not necessarily correlate with the uptake of larger dietary antigens. This review analyzes both the structural and functional aspects of intestinal permeability with special emphasis on antigen handling in healthy and diseased states and consequences on local immune responses to food ...
In typical permeability experiments, a disk sample is sealed gas tight over a support tube. A gas or gas mixture is supplied to one side, and one or more species permeate to the other side, where a sweep gas and/or pump collect the gas. The modes of operation are numerous, and so are the ways to analyze the permeation, including gas chromatography (GC) and mass spectroscopy (MS). Typically, an inert gas added to the entry side gas mixture is used for monitoring the presence or absence of background leakage through seal leaks or sample cracks and porosity.. In general, a large sample area or tubular sample is preferable, as it reduces the relative effects of leakage from seal ring and general equipment. It also simplifies the considerations of sample geometry for samples where the thickness is not much smaller than the diameter so that permeation from the side is significant. However, a large sample may put higher requirements to the mechanical assembly and seal.. These articles refer to ...
A permeability meter is available to help companies overcome the problem of specifying seals to prevent damage caused by water vapour
Nevertheless, these factors interplay with the neuroendocrine network, gut-associated lymphoid tissue, intestinal barrier, and eventually, the integrity of tight junctions between the epithelial cells. Eventually, the correct function of these factors will control and promote a balanced immune response.. Did you know most common chronic diseases are associated with an autoimmune response? Chronic inflammatory diseases like diabetes mellitus type II, inflammatory bowel disease, multiple sclerosis, gestational diabetes, and hyperlipidemia, to name a few. Therefore, if we are going to deal with autoimmune diseases, then why not treat the predecessor of this mechanism? Treat the gut, improve intestinal permeability = healthy patient.. Why treat the gut if the patient came in with a metabolic disease? The intestinal barrier has a crucial function; it regulates macromolecules traffic from food to protect the host. Inflammation is the first stage of every disease, and increased intestinal permeability ...
It is observed that low permeability reservoir characteristics and controlling factors are unclear in Triassic Yanchang formation in Ordos Basin Jiyuan region.In response to this issue,resolution sequence stratigraphy,se
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Scott Richard Fidler (1998). Spatial and temporal variability of hydraulic response in fractured, low permeability sediments. UWSpace. http://hdl.handle.net/10012/240 ...
The permeability of one of the first and second shield layers in a read head is greater than the permeability of the other of the first and second shield layers for providing a net image current field HIM which can be employed for counterbalancing other fields acting on a free layer structure in a spin valve sensor such as a sense current field HI in either a top or bottom single spin valve sensor or a net ferromagnetic coupling field HFC alone or in combination with a demagnetizing field HD in a dual spin valve sensor. Preferred high permeability materials are nickel iron or nickel iron alloys excluding cobalt and low permeability materials are cobalt based.
Mitochondrial Permeability Transition (MPT) is reported as the mechanism of acetaminophen induced hepatic damage, however, rat models are resistant to acetaminophen induced toxicity. The occurrence and degree of mitochondrial permeability transition after treatment with 400 mg kgG1 of acetaminophen in albino Wistar rats were assessed. Animals were randomly distributed into seven groups; control, 12, 24, 36, 48, 60 and 72 h based on varying time (in hour) post acetaminophen prior to sacrifice after treatment. Mitochondrial Membrane Permeability Transition (MMPT) pore opening and mitochondrial cytochrome c release were estimated. Opening of MMPT pore and cytochrome c release were observed in 12, 24, 36 and 72 h, when compared with the control group. Liver function and histological results indicated no liver damage. It is concluded that toxic dose of acetaminophen induced mitochondrial permeability transition in rat hepatic tissues without leading to necrotic damage suggesting that rat hepatic ...
A memory device is provided with a structure for improved transmission line operation on integrated circuits. The structure for transmission line operation includes a first layer of electrically conductive material on a substrate. A first layer of insulating material is formed on the first layer of the electrically conductive material. A number of high permeability metal lines are formed on the first layer of insulating material. The number of high permeability metal lines includes composite hexaferrite films. A number of transmission lines is formed on the first layer of insulating material and between and parallel with the number of high permeability metal lines. A second layer of insulating material is formed on the transmission lines and the high permeability metal lines. The structure for transmission line operation includes a second layer of electrically conductive material on the second layer of insulating material.
OBJECTIVES: Chronic liver disease (CLD) is associated with both alterations of the stool microbiota and increased small intestinal permeability. However, little is known about the role of the small intestinal mucosa-associated microbiota (MAM) in CLD. The aim of this study was to evaluate the relationship between the duodenal MAM and both small intestinal permeability and liver disease severity in CLD. METHODS: Subjects with CLD and a disease-free control group undergoing routine endoscopy underwent duodenal biopsy to assess duodenal MAM by 16S rRNA gene sequencing. Small intestinal permeability was assessed by a dual sugar (lactulose: rhamnose) assay. Other assessments included transient elastography, endotoxemia, serum markers of hepatic inflammation, dietary intake, and anthropometric measurements. RESULTS: Forty-six subjects (35 with CLD and 11 controls) were assessed. In subjects with CLD, the composition (P = 0.02) and diversity (P , 0.01) of the duodenal MAM differed to controls. ...
TY - JOUR. T1 - The mitochondrial permeability transition from in vitro artifact to disease target. AU - Bernardi, Paolo. AU - Krauskopf, Alexandra. AU - Basso, Emy. AU - Petronilli, Valeria. AU - Blalchy-Dyson, Elizabeth. AU - Di Lisa, Fabio. AU - Forte, Michael. PY - 2006/5. Y1 - 2006/5. N2 - The mitochondrial permeability transition pore is a high conductance channel whose opening leads to an increase of mitochondrial inner membrane permeability to solutes with molecular masses up to ≈1500 Da. In this review we trace the rise of the permeability transition pore from the status of in vitro artifact to that of effector mechanism of cell death. We then cover recent results based on genetic inactivation of putative permeability transition pore components, and discuss their meaning for our understanding of pore structure. Finally, we discuss evidence indicating that the permeability transition pore plays a role in pathophysiology, with specific emphasis on in vivo models of disease.. AB - The ...
Tryptanthrin and (E,Z)-3-(4-hydroxy-3,5-dimethoxybenzylidene)indolinone (indolinone) were recently isolated from Isatis tinctoria as potent anti-inflammatory and antiallergic alkaloids, and shown to inhibit COX-2, 5-LOX catalyzed leukotriene synthesis, and mast cell degranulation at low µM to nM concentrations. To assess their suitability for oral administration, we screened the compounds in an in vitro intestinal permeability assay using human colonic adenocarcinoma cells. For exact quantification of the compounds, validated UPLC-MS/MS methods were used. Tryptanthrin displayed high permeability (apparent permeability coefficient , 32.0 × 10(-6) cm/s) across the cell monolayer. The efflux ratio below 2 (, 1.12) and unchanged apparent permeability coefficient values in the presence of the P-glycoprotein inhibitor verapamil (50 µM) indicated that tryptanthrin was not involved in P-glycoprotein interactions. For indolinone, a low recovery was found in the human colon adenocarcinoma cell assay. ...
TY - JOUR. T1 - The mitochondrial permeability transition from yeast to mammals. AU - Azzolin, Luca. AU - von Stockum, Sophia. AU - Basso, Emy. AU - Petronilli, Valeria. AU - Forte, Michael A.. AU - Bernardi, Paolo. PY - 2010/6. Y1 - 2010/6. N2 - Regulated permeability changes have been detected in mitochondria across species. We review here their key features, with the goal of assessing whether a permeability transition similar to that observed in higher eukaryotes is present in other species. The recent discoveries (i) that treatment with cyclosporin A (CsA) unmasks an inhibitory site for inorganic phosphate (Pi) [Basso, E., Petronilli, V., Forte, M.A. and Bernardi, P. (2008) Phosphate is essential for inhibition of the mitochondrial permeability transition pore by cyclosporin A and by cyclophilin D ablation. J. Biol. Chem. 283, 26307-26311], the classical inhibitor of the permeability transition of yeast and (ii) that under proper experimental conditions a matrix Ca2+-dependence can be ...
TY - JOUR. T1 - Oxygen permeability and stability of Al2O3-doped SrCo0.8Fe0.2O3-δ mixed conducting oxides. AU - Wu, Zhentao. AU - Jin, Wanqin. AU - Xu, Nanping. PY - 2006/8/1. Y1 - 2006/8/1. N2 - A new series of Al2O3-doped SrCo0.8Fe0.2O3-δ (SCFA) mixed conducting oxides were synthesized by the conventional solid-state reaction method. Effects of doping Al2O3 (1, 3, 5 and 10 wt.%, respectively) on the crystal structure, order-disorder phase transition, microstructure, oxygen permeability and structure stability of SrCo0.8Fe0.2O3-δ (SCF) were investigated by XRD, TG-DSC, SEM, oxygen permeation measurement and the partial oxidation of methane (POM) to syngas reaction. Although the oxygen permeability of the SCF was weakened in the oxygen permeation measurement at the air/He gradient due to the doping of Al2O3, perovskite structure of SCFA was found stable in the low oxygen partial pressure (about 1.01325 × 102 Pa (10-3 atm)). In the POM reaction, the rate of the oxygen permeation of SCFA3 (the ...
Absolute Open Flow Potential (AOFP) is often the only productivity information available from low permeability gas formations particularly in the Appalachian Basin. Absolute Open Flow Potential (AOFP) is commonly evaluated through a single point test due to its cost effectiveness. In low permeability reservoirs, the time required for obtaining stabilized flow rate is often very long. Therefore, stabilized AOFP may not be achieved in short tests. Furthermore, most low permeability gas wells are hydraulically fractured to improve their productivity. Therefore, the post-fracture measured AOFP could be significantly influenced by fracture properties.;The objective of this was to develop a methodology to estimate formation properties from AOFP. Conventional methods for pressure transient analysis or deliverability testing analysis cannot be used since they require multiple pressure and rate data. To achieve the objective, the impact of formation properties on AOFP was studied. Several different solutions
Previous studies indicated that the micro integral membrane protein located within the media place of the integral membrane protein of Lactobacillus plantarum CGMCC 1258 had protective effects against the intestinal epithelial injury. In our study, we mean to establish micro integral membrane protein -knockout Lactobacillus plantarum (LPKM) to investigate the change of its protective effects and verify the role of micro integral membrane protein on protection of normal intestinal barrier function. Binding assay and intestinal permeability were performed to verify the protective effects of micro integral membrane protein on intestinal permeability in vitro and in vivo. Molecular mechanism was also determined as the zonulin pathway. Clinical data were also collected for further verification of relationship between zonulin level and postoperative septicemia. LPKM got decreased inhibition of EPEC adhesion to NCM460 cells. LPKM had lower ability to alleviate the decrease of intestinal permeability induced by
Previous studies indicated that the micro integral membrane protein located within the media place of the integral membrane protein of Lactobacillus plantarum CGMCC 1258 had protective effects against the intestinal epithelial injury. In our study, we mean to establish micro integral membrane protein -knockout Lactobacillus plantarum (LPKM) to investigate the change of its protective effects and verify the role of micro integral membrane protein on protection of normal intestinal barrier function. Binding assay and intestinal permeability were performed to verify the protective effects of micro integral membrane protein on intestinal permeability in vitro and in vivo. Molecular mechanism was also determined as the zonulin pathway. Clinical data were also collected for further verification of relationship between zonulin level and postoperative septicemia. LPKM got decreased inhibition of EPEC adhesion to NCM460 cells. LPKM had lower ability to alleviate the decrease of intestinal permeability induced by
Here, we advanced a novel technique using capillary ultrafiltration (CUF) probes to collect in vivo secreted proteins in the subcutaneous tissue of mouse ear. We fabricated two kinds of CUF probe, one with and one without a semi-permeable membrane hollow fiber. Proteins collected by CUF probes were profiled and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MADLI-TOF-MS) and quadrupole time-of-flight tandem mass spectrometry (Q-TOF-MS/MS) without using two-dimensional gel electrophoresis (2-DE) separation. Five proteins including cofilin-1, futuin-A, complement C3, gelsolin, and apolipoprotein C-1 were identified from the sample collected by the CUF probe with a semi-permeable membrane hollow fiber. The presence of well documented secretory proteins supports the efficiency of CUF probes in sampling in vivo secreted proteins. We also found that hemoglobin collected by the CUF probe without a semi-permeable membrane hollow fiber completely masked ...
Conjunctiva occupies most of the ocular surface area, and conjunctival permeability affects ocular and systemic drug absorption of topical ocular medications. Therefore, the aim of this study was to obtain a computational in silico model for structure-based prediction of conjunctival drug permeability. This was done by employing cassette dosing and quantitative structure-property relationship (QSPR) approach. Permeability studies were performed ex vivo across fresh porcine conjunctiva and simultaneous dosing of a cassette mixture composed of 32 clinically relevant drug molecules with wide chemical space. The apparent permeability values were obtained using drug concentrations that were quantified with liquid chromatography tandem-mass spectrometry. The experimental data were utilized for building a QSPR model for conjunctival permeability predictions. The conjunctival permeability values presented a 17-fold range (0.63-10.74 × 10−6 cm/s). The final QSPR had a Q2 value of 0.62 and predicted ...
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BACKGROUND: Intestinal permeability and adipose tissue inflammation are considered mechanistic links in the relationship between diet, obesity, and chronic disease. However, methods to measure both are not well standardized, and the reliability of commonly used measures is not known. METHODS: We calculated the intraclass correlation coefficient (ICC) for several common measures of intestinal permeability and adipose tissue inflammation from a randomized clinical trial of cross-over design in which normal weight (n=12) or overweight/obese (n=12) individuals each completed three 8-day dietary intervention periods. RESULTS: For biomarkers of intestinal permeability, plasma zonulin and lipopolysaccharide binding protein, ICCs were excellent (i.e., , 0.9). The direct measure of intestinal permeability, the lactulose/mannitol test, exhibited fair reliability (ICC=0.53). A wider range of ICCs (0.6-0.9), suggesting good to excellent reliability, were obtained for measures of adipose tissue ...
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(1) The specifically regulated restrictive permeability barrier to cells and molecules is the most important feature of the blood-brain barrier (BBB). The aim of this review was to summarize permeability data obtained on in vitro BBB models by measurement of transendothelial electrical resistance and by calculation of permeability coefficients for paracellular or transendothelial tracers. (2) Results from primary cultures of cerebral microvascular endothelial cells or immortalized cell lines from bovine, human, porcine, and rodent origin are presented. Effects of coculture with astroglia, neurons, mesenchymal cells, blood cells, and conditioned media, as well as physiological influence of serum components, hormones, growth factors, lipids, and lipoproteins on the barrier function are discussed. (3) BBB permeability results gained on in vitro models of pathological conditions including hypoxia and reoxygenation, neurodegenerative diseases, or bacterial and viral infections have been
A disulphimide group-containing acrylonitrile copolymer semi-permeable membrane which comprises:(A) from 99 to 50% by weight of acrylonitrile units;(B) from 1 to 50% by weight of units of an acrylonitrile-copolymerizable ethylenically unsaturated monomer containing one or two disulphimide groups; and(C) from 0 to 30% by weight of units of one or more other acrylonitrile-copolymerizable olefinically unsaturated monomer, the sum of the percentages amounts to 100.The semi-permeable membranes may be used in reverse osmosis and ultrafiltration.
Hydraulic fracturing in shales is challenging because of the complicated stress status. The confining pressure imposed on a shale formation has a tremendous impact on the permeability of the rock. The correlation between confining pressure and rock permeability is complicated and might be nonlinear. Gas flow in low-permeability shales differs significantly from liquid flow because of the Klinkenberg effect, especially when the pore pressure is relatively low. The Klinkenberg effect results from gas molecule slip at the solid walls inside the nanopores, where the collision between gas molecules and solid surfaces is more frequent than the collision between gas molecules. This effect causes the increase of apparent permeability (i.e., the measured permeability). In this study, the simple effective stress law and the effective stress coefficient law were used to study the relationship between permeability and effective stress. In the simple effective stress law, the effective stress is calculated ...
TY - JOUR. T1 - Ammonia neurotoxicity. T2 - Role of the mitochondrial permeability transition. AU - Rama Rao, K. V.. AU - Jayakumar, A. R.. AU - Norenberg, M. D.. PY - 2003/6/1. Y1 - 2003/6/1. N2 - Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with severe liver disease. Although the mechanisms responsible for HE remain elusive, ammonia is generally considered to be involved in its pathogenesis, and astrocytes are thought to be the principal target of ammonia neurotoxicity. Altered bioenergetics and oxidative stress are also thought to play a major role in this disorder. In this paper, we present data invoking the mitochondrial permeability transition (MPT) as a factor in the pathogenesis of HE/hyperammonemia. The MPT is a Ca2+-dependent, cyclosporin A (CsA) sensitive process due to the opening of a pore in the inner mitochondrial membrane that leads to a collapse of ionic gradients and ultimately to mitochondrial dysfunction. Many of the factors that ...
Background and aim: Persistent stress and life events affect the course of ulcerative colitis (UC) by largely unknown mechanisms. Regulation of epithelial permeability to antigens is crucial for the balance between inflammation and immuno-surveillance, and increased intestinal permeability has been shown in patients with ulcerative colitis. Corticotropin releasing hormone (CRH) has been implicated as an important mediator of stress-induced abnormalities in intestinal mucosal function in animal models. Further cholinergic signalling during stress. has been reported to increase bowel ion secretion in humans and uptake of HRP in rodents via activation of mast cells.. The overall aim of this thesis was to examine the role of CRH-mediated and cholinergic signalling, and their interaction with mast cells and eosinophils, in the regulation of the mucosal barrier function in the normal human colon and in UC. In vivo studies or the use of surgical specimens for such studies have major shortcomings. ...
K. Ward, I. Bjarnason, P. Smethurst, T.J. Peters; Sequential Measurements of Small Intestinal Permeability in Chronic Alcoholics. Clin Sci (Lond) 1 February 1984; 66 (2): 63P. doi: https://doi.org/10.1042/cs066063Pa_pt2. Download citation file:. ...
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Epithelial damage caused by intestinal permeation enhancers is a source of debate over their safety. The medium chain fatty acid, sodium caprate (C10), causes reversible membrane perturbation at high dose levels required for efficacy in vivo, so the aim was to model it in vitro. Exposure of Caco-2 monolayers to 8.5mM C10 for 60min followed by incubation in fresh buffer led to (i) recovery in epithelial permeability (i.e. transepithelial electrical resistance (TEER) and apparent permeability coefficient (Papp) of [(14)C]-mannitol), (ii) recovery of cell viability parameters (monolayer morphology, plasma membrane potential, mitochondrial membrane potential, and intracellular calcium) and (iii) reduction in mRNA expression associated with inflammation (IL-8). Pre-incubation of monolayers with a mucosal prostaglandin cytoprotectant was attempted in order to further decipher the mechanism of C10. Misoprostol (100nM), inhibited C10-induced changes in monolayer parameters, an effect that was partially ...
Prediction of blood-brain barrier permeability of organic compounds / A. S. Dyabina, E. V. Radchenko, V. A. Palyulin, N. S. Zefirov // Doklady Biochemistry and Biophysics. - 2016. - Vol. 470, no. 1. - P. 371-374. Using fragmental descriptors and artificial neural networks, a predictive model of the relationship between the structure of organic compounds and their blood-brain barrier permeability was constructed and the structural factors affecting the readiness of this penetration were analyzed. This model (N = 529, Q2 = 0.82, RMSEcv = 0.32) surpasses the previously published models in terms of the prediction accuracy and the applicability domain and can be used for the optimization of the pharmacokinetic parameters during drug development. [ DOI ...
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In this study, a facile, ecofriendly nanocomposite based on glycerol-plasticized thermoplastic potato starch (TPS) containing 0-4 wt.% cellulose nanofiber (CNF) from pineapple leaf was prepared by the solution casting technique. The nanocomposite films showed better mechanical properties compared to neat film. The tensile properties were fit with theoretical predictions. Tensile strength increased with CNF loading and reached up to 4.682 MPa (TPS+3 wt.% CNF) from 1.58 MPa (neat TPS), an improvement of ~196% over the neat polymer. The addition of cellulose nanofiber improved the barrier properties of films by creating a tortuous path for penetrant molecules. Gas transport behavior of CNF-based TPS nanocomposite films was explored using O2 gas. A 56% decrease (relative to neat TPS) in oxygen permeability of the nanocomposite membranes was achieved by adding only 3 wt.% CNF. The oxygen permeability data were fit with two theoretical ...
1.Previous studies have indicated that the permeability of polyethyleneglycol across the human intestine is anomalously high in comparison with the permeability of sugars with similar molecular mass. In consequence it has been proposed that two or more distinct mechanisms must exist for the translocation of these classes of molecule or, alternatively, that the molecular parameter determining rate of penetration is each molecules minimum molecular dimension.. 2.The notional hydrogen-bonding capacity of a molecule correlates well with oil-water partition coefficient and also, in a variety of experimental systems, with rate of passive diffusion across biological membranes. A molecules hydrogen-bonding capacity is calculated by inspecting the structural formula and summing the individual theory-derived hydrogen-bonding capacities of the molecules functional groups.. 3.A classic set of intestinal permeability data that includes several ethyleneglycol oligomers and several sugars is re-analysed. A ...
Permeability is the property of rocks that is an indication of the ability for fluids (gas or liquid) to flow through rocks. High permeability will allow fluids to move rapidly through rocks. Permeability is affected by the pressure in a rock. The unit of measure is called the darcy, named after Henry Darcy (1803-1858). Sandstones may vary in permeability from less than one to over 50,000 millidarcys (md). Permeabilities are more commonly in the range of tens to hundreds of millidarcies. A rock with 25% porosity and a permeability of 1 md will not yield a significant flow of water. Such tight rocks are usually artificially stimulated (fractured or acidized) to create permeability and yield a flow.. ...
On the other hand, clay has low permeability due to small grain sizes with large surface areas, which results in increased friction. Also these pore spaces are not well connected. Clay often creates confining layers in the subsurface. (http://www.co.portage.wi.us/groundwater/undrstnd/soil.htm). Therefore, for this experiment to test for the permeability of soil is using the constant head test. The constant head permeability test is a common laboratory testing method used to determine the permeability of granular soils like sands and gravel containing little or no slit. This testing method is made for testing reconstituted or disturbed granular soil samples. The constant head permeability test involves flow of water through a column of cylindrical soil sample under the constant pressure difference. The test is carried out in the permeability cell, which can vary in size depending on the grain size of the tested material. (http://www.geotechdata.info/geotest/constant-head-permeability-test.html) ...
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To ensure the effective long-term storage of CO2 in candidate geological storage sites, evaluation of potential leakage pathways to the surface should be undertaken. Here we use a series of natural CO2 seeps along a fault in South Africa to assess the controls on CO2 leakage to the surface. Geological mapping and detailed photogrammetry reveals extensive fracturing along the mapped fault trace. Measurements of gas flux and CO2 concentration across the fracture corridor give maximum soil gas measurements of 27% CO2 concentration and a flux of 191 g m−2 d−1. These measurements along with observations of gas bubbles in streams and travertine cones attest to CO2 migration to the surface. Permeability measurements on the host rock units show that the tillite should act as an impermeable seal to upward CO2 migration. The combined permeability and fracture mapping data indicate that fracture permeability creates the likely pathway for CO2 migration through the low permeability tillite to the ...
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This is the first report of the immunohistological features of resolution of acute Campylobacterenterocolitis, and the first to report the striking increase in EC numbers and changes in macrophages and T lymphocytes which, in at least some patients, can persist for more than a year. This description is particularly important because similar changes were found in outpatients with prolonged IBS symptoms following acute bacterial enteritis. The persistence of these changes and their detection in symptomatic outpatients supports our hypothesis that the changes we have described following bacterial enteritis are in part responsible for the persistent symptoms commonly seen in clinical practice. This cohort study required a rather arduous protocol, with patients undergoing three rectal biopsies and two determinations of gut permeability. Although 47 patients agreed to participate, only 21 completed the three visits. However, as shown in table 1, those who did were demographically similar to those who ...
TY - JOUR. T1 - β-Sheet breaker peptide inhibitor of Alzheimers amyloidogenesis with increased blood-brain barrier permeability and resistance to proteolytic degradation in plasma. AU - Poduslo, Joseph F.. AU - Curran, Geoffry L.. AU - Kumar, Asok. AU - Frangione, Blas. AU - Soto, Claudio. PY - 1999/6/5. Y1 - 1999/6/5. N2 - Short synthetic peptides homologous to the central region of Aβ but bearing proline residues as β-sheet blockers have been shown in vitro to bind to Aβ with high affinity, partially inhibit Aβ fibrillogenesis, and redissolve preformed fibrils. While short peptides have been used extensively as therapeutic drugs in medicine, two important problems associated with their use in central nervous system diseases have to be addressed: (a) rapid proteolytic degradation in plasma, and (b) poor blood-brain barrier (BBB) permeability. Recently, we have demonstrated that the covalent modification of proteins with the naturally occurring polyamines significantly increases their ...
TY - JOUR. T1 - Permeability decay in CAVH hemofilters. AU - Jenkins, R. D.. AU - Kuhn, R. J.. AU - Funk, J. E.. PY - 1988. Y1 - 1988. N2 - Change in hydraulic permeability over time was measured in four types of continuous arteriovenous hemofiltration (CAVH) hemofilters in order to characterize permeability decay and demonstrate that permeability decay occurs without membrane protein exposure. Polyamide, polysulfone, and polyacrylonitrile membrane hemofilters were placed in a gravity-driven in vitro CAVH apparatus. Distilled and deionized water or saline was used to perfuse the hemofilters. A biphasic pattern of permeability decay was seen in all hemofilter types. A large exponential decline in permeability occurred over the first 1 to 6 hours, with a more gradual decay thereafter. Of all membranes studied, polysulfone hemofilters were the most permeable upon initiation of use but showed the most pronounced early and late permeability decay. Both polyamide and polyacrylonitrile hemofilters ...
Selective Permeability - What is it? Selective permeability means that the cell membrane has some control over what can cross it, so that only certain molecules either enter or leave the cell.
Early age cracking of bridge decks is a national problem, and may substantially reduce service lives and increase maintenance costs. Cracking occurs when the tensile stress exceeds the tensile strength of the concrete. This is a time-dependent phenomenon, since both the stress and strength change at early ages. Moisture loss increases stress (with increasing shrinkage) and impairs strength gain. Internal curing is one method that has been suggested to reduce early age bridge deck cracking, particularly of concretes with low water to cementitious materials (w/cm) ratios. Many state highway agencies have implemented high performance concrete (HPC) for bridge decks. The low permeability of HPC is used to protect reinforcing steel and prevent corrosion. However, if the concrete cracks, then the protection may be greatly diminished. Transverse cracks due to concrete shrinkage allow water and corrosive chemicals to quickly reach the reinforcing steel causing corrosion and shortening the lifespan of ...
purpose. To investigate the relationship between scleral permeability and nonenzymatic cross-link density.. methods. Scleral discs 18 mm in diameter were dissected from the medial and lateral equatorial regions of 60 cadaveric porcine eyes. Samples were incubated for 24 hours with control solution or methylglyoxal at concentrations of 0.001%, 0.01%, 0.10%, and 1.00%. Nonenzymatic cross-link density in treated and control groups was quantified with the use of papain digest and fluorescence spectrophotometry. Treated scleral discs were mounted in a customized Ussing-type chamber connected to vertical tubing, and specific hydraulic conductivity was determined according to the descent of a column of degassed saline at room temperature. Permeability to diffusion of fluorescein in a static chamber was determined for another set of treated scleral samples.. results. Methylglyoxal treatment effectively increased nonenzymatic cross-link content, as indicated by the average fluorescence for each group. ...
Table 1 : Correlation between properties of a green sand containing 8 parts of bentonite [1] Permeability doesnt correlate well with any of these tests. The amount of water flowing through a certain area can be represented by the coefficient of permeability. After compacting thin layers of the prepared granular soil sample in the permeameter, a special sliding-weight compaction hammer or vibrating tamper provides a higher relative density if required. The above values have been provided with both imperial and metric units. Permeability is the property or capacity of a porous rock, sediment, or soil for transmitting a fluid; it is a measure of the relative ease of fluid flow under unequal pressure (Bates and Jackson, 1980).The most significant characteristic of mudstones, siltstones and shales are their extremely low permeability. 10-6 - 10-7. These soils easily become waterlogged, and plant roots can suffocate as a result. Permeability Permeability is the quality of soil that enables it to ...
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When there is damage to the intestinal lining it can open up slightly and this allows larger particles, such as undigested or partially digested foods and bacteria, to enter into the bloodstream. This leads to malabsorption of nutrients as they pass through into the blood stream in a form that the body cannot use and it can also lead to excessive absorption of bacteria and other molecules that the intestines usually prevent from entering the blood stream.. The immune system is not used to these particles and sees them as foreign and you can develop food sensitivities and candida infections as a result. This can lead to inflammation, irritation and allergic like reactions. Both malabsorption and increased intestinal permeability (leaky gut) are associated with chronic gastrointestinal imbalances as well as many systemic disorders.. The Cyrex Array 2….Intestinal Antigenic Permeability Screen™, identifies an immune response indicating damage to the intestinal mucosal microstructures, ...
Mitochondria play an important role in energy production, Ca2+ homeostasis and cell death. In recent years, the role of the mitochondria in apoptotic and necrotic cell death has attracted much attention. In apoptosis and necrosis, the mitochondrial permeability transition (mPT), which leads to disru …
Mitochondrial dysfunction in heart failure includes greater susceptibility to mitochondrial permeability transition (MPT), which may worsen cardiac function and decrease survival. Treatment with a mixture of the n3 polyunsaturated fatty acids (n3 PUF
Looking for cell permeability? Find out information about cell permeability. The permitting or activating of the passage of substances into, out of, or through cells, or from one cell to another. These materials traverse either the... Explanation of cell permeability
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Gas shales and tight reservoirs exhibit extremely low permeability. This low permeability makes it difficult to apply traditional transport modeling approaches, such as Darcys law, to shales [9, 10]. Gas flow in organic matter, natural fractures, and hydraulic fractures occurs via different mechanisms: continuum flow, slip flow, and Knudsen diffusion. Adsorbed gas desorption from the organic matter also plays a role in gas transport [11]. It is challenging to develop a comprehensive model to describe the multiple mechanisms in the gas transport process.. S. Huang et al. proposed a comprehensive apparent permeability model to consider the multiple transport mechanisms in shale gas reservoirs. The specific mechanisms include viscous flow, slip flow, Knudsen diffusion, and surface diffusion. In their model, the pore diameter and mean free path of gas molecules are corrected by considering the adsorption layer and dense gas effect.. Y. Zeng et al. develop a modified apparent permeability model to ...