Готові списки джерел за темами / Solute permeability

Добірка наукової літератури з теми "Solute permeability"

Автор: Grafiati

Опубліковано: 21 липня 2022

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Статті в журналах з теми "Solute permeability":

Cordeiro, Margarida M., Armindo Salvador, and Maria João Moreno. "Calculation of Permeability Coefficients from Solute Equilibration Dynamics: An Assessment of Various Methods." Membranes 12, no. 3 (February 23, 2022): 254. http://dx.doi.org/10.3390/membranes12030254.

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Predicting the rate at which substances permeate membrane barriers in vivo is crucial for drug development. Permeability coefficients obtained from in vitro studies are valuable for this goal. These are normally determined by following the dynamics of solute equilibration between two membrane-separated compartments. However, the correct calculation of permeability coefficients from such data is not always straightforward. To address these problems, here we develop a kinetic model for solute permeation through lipid membrane barriers that includes the two membrane leaflets as compartments in a four-compartment model. Accounting for solute association with the membrane allows assessing various methods in a wide variety of conditions. The results showed that the often-used expression Papp = β × r/3 is inapplicable to very large or very small vesicles, to moderately or highly lipophilic solutes, or when the development of a significant pH gradient opposes the solute’s flux. We establish useful relationships that overcome these limitations and allow predicting permeability in compartmentalised in vitro or in vivo systems with specific properties. Finally, from the parameters for the interaction of the solute with the membrane barrier, we defined an intrinsic permeability coefficient that facilitates quantitative comparisons between solutes.

Adamson, R. H., V. H. Huxley, and F. E. Curry. "Single capillary permeability to proteins having similar size but different charge." American Journal of Physiology-Heart and Circulatory Physiology 254, no. 2 (February 1, 1988): H304—H312. http://dx.doi.org/10.1152/ajpheart.1988.254.2.h304.

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We investigated the hypothesis that solute charge modulates transcapillary exchange in microvessels with continuous endothelium. Two globular proteins, alpha-lactalbumin and ribonuclease, having approximately the same size (mol wt 14,176 and 13,683, respectively) but different net charge (-10 and +4, respectively) were test solutes. Each solute was labeled with the fluorescent probe tetramethylrhodamine isothiocyanate. Labeling did not significantly change solute size, but increased negative charge on each solute by one valency unit. An in vivo fluorescent microscope technique [Huxley et. al., Am. J. Physiol. 252 (Heart Circ. Physiol. 21): H188-H197, 1987] was used to measure solute permeability coefficients (P) in single microvessels of frog mesentery at 14-16 degrees C. The mean P for alpha-lactalbumin, measured when capillary pressure was 10 cmH2O, was 2.1 X 10(-6) cm/s and the mean P for ribonuclease was 4.3 X 10(-6) cm/s. Our results conform to the hypothesis that the transcapillary pathways of frog mesenteric microvessels are negatively charged. With the use of a Donnan-type model for electrostatic partitioning, charge density in the pathway is estimated as 11.4 meq/l. Comparison of measured Ps with those for small solutes in frog mesenteric microvessels indicates that molecular size is a proportionally more significant determinant of solute permeability in continuous capillaries than is solute charge.

Fu, Bingmei M., Roger H. Adamson, and Fitz-Roy E. Curry. "Determination of Microvessel Permeability and Tissue Diffusion Coefficient of Solutes by Laser Scanning Confocal Microscopy." Journal of Biomechanical Engineering 127, no. 2 (September 18, 2004): 270–78. http://dx.doi.org/10.1115/1.1865186.

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Interstitium contains a matrix of fibrous molecules that creates considerable resistance to water and solutes in series with the microvessel wall. On the basis of our preliminary studies (Adamson et al., 1994, Microcirculation 1(4), pp. 251–265; Fu et al., 1995 Am. J. Physiol. 269(38), pp. H2124–H2140), by using laser-scanning confocal microscopy and a theoretical model for interstitial transport, we determined both microvessel solute permeability (P) and solute tissue diffusion coefficient (Dt) of α-lactalbumin (Stokes radius 2.01nm) from the rate of tissue solute accumulation and the radial concentration gradient around individually perfused microvessel in frog mesentery. Pα‐lactalbumin is 1.7±0.7(SD)×10−6cm∕s(n=6). Dt∕Dfree for α-lactalbumin is 27%±5%(SD)(n=6). This value of Dt∕Dfree is comparable to that for small solute sodium fluorescein (Stokes radius 0.45nm), while Pα‐lactalbumin is only 3.4% of Psodiumfluorescein. Our results suggest that frog mesenteric tissue is much less selective to solutes than the microvessel wall.

Fu, Bingmei M., and Shang Shen. "Structural mechanisms of acute VEGF effect on microvessel permeability." American Journal of Physiology-Heart and Circulatory Physiology 284, no. 6 (June 1, 2003): H2124—H2135. http://dx.doi.org/10.1152/ajpheart.00894.2002.

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To investigate the ultrastructural mechanisms of acute microvessel hyperpermeability by vascular endothelial growth factor (VEGF), we combined a mathematical model ( J Biomech Eng 116: 502–513, 1994) with experimental data of the effect of VEGF on microvessel hydraulic conductivity ( L p) and permeability of various-sized solutes. We examined the effect of VEGF on microvessel permeability to a small solute (sodium fluorescein, Stokes radius 0.45 nm), an intermediate solute (α-lactalbumin, Stokes radius 2.01 nm), and a large solute [albumin (BSA), Stokes radius 3.5 nm]. Exposure to 1 nM VEGF transiently increased apparent permeability to 2.3, 3.3, and 6.2 times their baseline values for sodium fluorescein, α-lactalbumin, and BSA, respectively, within 30 s, and all returned to control within 2 min. On the basis of L p (DO Bates and FE Curry. Am J Physiol Heart Circ Physiol 271: H2520–H2528, 1996) and permeability data, the prediction from the model suggested that the most likely structural changes in the interendothelial cleft induced by VEGF would be a ∼2.5-fold increase in its opening width and partial degradation of the surface glycocalyx.

Niles, W. D., F. S. Cohen, and A. Finkelstein. "Hydrostatic pressures developed by osmotically swelling vesicles bound to planar membranes." Journal of General Physiology 93, no. 2 (February 1, 1989): 211–44. http://dx.doi.org/10.1085/jgp.93.2.211.

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When phospholipid vesicles bound to a planar membrane are osmotically swollen, they develop a hydrostatic pressure (delta P) and fuse with the membrane. We have calculated the steady-state delta P, from the equations of irreversible thermodynamics governing water and solute flows, for two general methods of osmotic swelling. In the first method, vesicles are swollen by adding a solute to the vesicle-containing compartment to make it hyperosmotic. delta P is determined by the vesicle membrane's permeabilities to solute and water. If the vesicle membrane is devoid of open channels, then delta P is zero. When the vesicle membrane contains open channels, then delta P peaks at a channel density unique to the solute permeability properties of both the channel and the membrane. The solute enters the vesicle through the channels but leaks out through the region of vesicle-planar membrane contact. delta P is largest for channels having high permeabilities to the solute and for solutes with low membrane permeabilities in the contact region. The model predicts the following order of solutes producing pressures of decreasing magnitude: KCl greater than urea greater than formamide greater than or equal to ethylene glycol. Differences between osmoticants quantitatively depend on the solute permeability of the channel and the density of channels in the vesicle membrane. The order of effectiveness is the same as that experimentally observed for solutes promoting fusion. Therefore, delta P drives fusion. When channels with small permeabilities are used, coupling between solute and water flows within the channel has a significant effect on delta P. In the second method, an impermeant solute bathing the vesicles is isosmotically replaced by a solute which permeates the channels in the vesicle membrane. delta P resulting from this method is much less sensitive to the permeabilities of the channel and membrane to the solute. delta P approaches the theoretical limit set by the concentration of the impermeant solute.

Mullen, T. L., M. Muller, and J. T. Van Bruggen. "Role of solute drag in intestinal transport." Journal of General Physiology 85, no. 3 (March 1, 1985): 347–63. http://dx.doi.org/10.1085/jgp.85.3.347.

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This study presents experiments related to the role of solvent drag and solute drag in the transmembrane movement of nonelectrolytes in a perfused rat intestine preparation. Conditions were chosen to simulate the effects of luminal hyperosmolarity on the permeability of tracer solutes. Data are presented on net water flux, transepithelial potentials, and lumen-to-blood and blood-to-lumen tracer solute movements during control electrolyte perfusion and after making the perfusate hyperosmotic. The results indicate that both solvent drag and solute drag can play significant roles in the transepithelial movement of solute and solute permeabilities in the rat ileum preparation. It is suggested that the potential roles of solvent drag and solute drag should be accounted for or considered during the characterization of the mechanisms of biological membrane function.

Varunkumar, M., and P. Muthu. "Fluid Flow and Solute Transfer in a Tube with Variable Wall Permeability." Zeitschrift für Naturforschung A 74, no. 12 (December 18, 2019): 1057–67. http://dx.doi.org/10.1515/zna-2019-0071.

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AbstractWe considered a steady flow of viscous incompressible fluid and solute transfer in an axisymmetric tube of uniform cross section with variable wall permeability, which is relevant to the study of movement of solute across the glomerular capillaries. The solutions for the nonlinear governing equations of the fluid flow and solute transfer are obtained by analytical/numerical methods. The combined effect of variable wall permeability and flow parameters on the hydrostatic pressure, osmotic pressure, velocity profiles, concentration profiles, and the total solute clearance are investigated and are presented in this paper. It is found that an increase in the variable permeability parameter increases the solute concentration at the wall.

Antonenkov, Vasily D., and J. Kalervo Hiltunen. "Peroxisomal membrane permeability and solute transfer." Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1763, no. 12 (December 2006): 1697–706. http://dx.doi.org/10.1016/j.bbamcr.2006.08.044.

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Zaheer, Muhammad, Hadayat Ullah, Saad Ahmed Mashwani, Ehsan ul Haq, Syed Husnain Ali Shah, and Fawaz Manzoor. "SOLUTE TRANSPORT MODELLING IN LOW-PERMEABILITY HOMOGENEOUS AND SATURATED SOIL MEDIA." Rudarsko-geološko-naftni zbornik 36, no. 2 (2021): 25–32. http://dx.doi.org/10.17794/rgn.2021.2.3.

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Fickian and non-Fickian behaviors were often detected for contaminant transport activity owed to the preferential flow and heterogeneity of soil media. Therefore, using diverse methods to measure such composite solute transport in soil media has become an important research topic for solute transport modeling in soil media. In this article, the continuous-time random walk (CTRW) model was applied to illustrate the relative concentration of transport in low-permeability homogeneous and saturated soil media. The solute transport development was also demonstrated with the convection-dispersion equation (CDE) and Two Region Model (TRM) for comparison. CXTFIT 2.1 software was used for CDE and TRM, and CTRW Matlab Toolbox v.3.1 for the CTRW simulation of the breakthrough curve. It was found that higher values of determination coefficient (R2) and lower values of root mean square error (RMSE) concerning the best fits of CDE, TRM, and CTRW. It was found that in the comparison of CDE, TRM, and CTRW, we tend to use CTRW to describe the transport behavior well because there are prevailing Fickian and non-Fickian transport. The CTRW gives better fitting results to the breakthrough curves (BTCs) when β has an increasing pattern towards 2.00. In this study, the variation of parameters in three methods was investigated and results showed that the CTRW modeling approach is more effective to determine non-reactive contaminants concentration in low-permeability soil media at small depths.

Kevil, Christopher G., Tadayuki Oshima, Brett Alexander, Laura L. Coe, and J. Steven Alexander. "H2O2-mediated permeability: role of MAPK and occludin." American Journal of Physiology-Cell Physiology 279, no. 1 (July 1, 2000): C21—C30. http://dx.doi.org/10.1152/ajpcell.2000.279.1.c21.

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H2O2-mediated elevation in endothelial solute permeability is associated with pathological events such as ischemia-reperfusion and inflammation. To understand how H2O2mediates increased permeability, we investigated the effects of H2O2administration on vascular endothelial barrier properties and tight junction organization and function. We report that H2O2exposure caused an increase in endothelial solute permeability in a time-dependent manner through extracellularly regulated kinase 1 and 2 (ERK1/ERK2) signal pathways. H2O2exposure caused the tight junctional protein occludin to be rearranged from endothelial cell-cell junctions. Occludin rearrangement involved redistribution of occludin on the cell surface and dissociation of occludin from ZO-1. Occludin also was heavily phosphorylated on serine residues upon H2O2administration. H2O2mediates changes in ERK1/ERK2 phosphorylation, increases endothelial solute permeability, and alters occludin localization and phosphorylation were all blocked by PD-98059, a specific mitogen-activated protein (MAP) or ERK kinase 1 inhibitor. These data strongly suggest that H2O2-mediated increased endothelial solute permeability involves the loss of endothelial tight junction integrity through increased ERK1/ERK2 activation.

Більше джерел

Дисертації з теми "Solute permeability":

Kemp, Paul J. "Ion and solute transport in alveolar type II pneumocytes." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253135.

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Kellen, Michael R. "A model for microcirculatory fluid and solute exchange in the heart /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/8124.

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Orsi, Mario. "The development of a coarse-grain biomembrane model and its use in multiscale simulations of solute permeability." Thesis, University of Southampton, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496091.

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A new simplified particle-based computer model for hydrated phosphohpid bilayers is presented. In the model, each lipid molecule, in reality comprising more than one hundrec atoms, is reduced to a collection of ten "'coarse-grain'' macrounits. Compared with available arse-grain methods, three novel aspects are introduced. First, electrostatics are explicitly incorporated via charges and dipoles. Second, water is accurately (yet efficiently) described, on an individual level, by the soft sticky dipole model. Third, hydrocarbon tails are modelled using the anisotropic Gay-Berne potential. Simulations are conducted by rigid body molecular dynamics, using software specifically designed and implemented for this project.

Larsbo, Mats. "An improved dual-permeability model of solute transport in structured soils : model development and parameter identification in laboratory and field experiments /." Uppsala : Dept. of Soil Sciences, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200551.pdf.

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Sedin, John. "Prevention of Postoperative Duodenal Ileus by COX-2 Inhibition Improves Duodenal Function in Anaesthetised Rats." Doctoral thesis, Uppsala universitet, Fysiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198049.

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Abdominal surgery inhibits gastrointestinal motility, a phenomenon referred to as postoperative ileus. Since the postoperative ileus disturbs duodenal physiology it is important to minimize the side effects of this condition. Recent experiments in our laboratory show that treatment of anaesthetised rats with parecoxib, a selective cyclooxygenase-2 inhibitor, prevents duodenal postoperative ileus, increases duodenal mucosal bicarbonate secretion and improves other functions as well. One aim of the thesis was to investigate whether removal of luminal chloride affect the parecoxib- and the vasoactive intestinal peptide (VIP)-induced stimulation of duodenal mucosal bicarbonate secretion. The proximal duodenum of anaesthetised Dark Agouti rats was perfused with isotonic solutions containing zero or low Cl- and the effect on luminal alkalinisation determined. The basal as well as the parecoxib-induced increase in alkalinisation, but not that stimulated by VIP, were markedly reduced in the absence of luminal Cl-. One important function of the duodenum is to adjust luminal osmolality towards that in the blood. It is believed that the adjustment of osmolality in the duodenum is achieved by osmosis and diffusion of electrolytes along their concentration gradients and that these processes occur predominately paracellularly. Another aim of the thesis was to examine whether prevention of postoperative ileus affects the duodenal response to luminal hypertonicity. The proximal duodenum of anaesthetised Dark Agouti and Sprague-Dawley rats were perfused with hypertonic solutions of different composition and osmolality and the effects on duodenal motility, alkaline secretion, transepithelial fluid flux, mucosal permeability and the adjustment of luminal osmolality were determined in absence and presence of parecoxib. It is concluded that COX-2 inhibition increases duodenal mucosal bicarbonate secretion by stimulating apical Cl-/HCO3- exchange in duodenocytes. Furthermore, pretreatment of anaesthetised rats with parecoxib improves a number of duodenal functions in both rat strains that contribute to improve the ability to adjust luminal osmolality. The choice of rat strain is another important feature to consider when interpreting the results because the DA strain was more responsive to luminal hypertonicity than the SD strain. Finally, several evidences are provided to suggest that the adjustment of luminal osmolality in the rat duodenum is a regulated process.

Tang, Zhenye, Jide Zhong, Xianqing Feng, Yafei Zhang, Yadi Hu, Hui Liu, Jie Liu, Cem Emre Ferah, and Keyong Tang. "Effects of soluble soybean polysaccharide as filling agent on the properties of leathers - 224." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34318.

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Content: Soluble soybean polysaccharide (SSPS) is good in emulsification, and stable emulsion may be formed with the addition of SSPS in fatliquoring agents. In this paper, with wet blues as raw materials, after being retanned and neutralized, fatliquoring and filling up with SSPS were carried out at the same time, with different amounts of SSPS, i.e., 1%, 3%, 5%,7% in weight. The leather samples were dried at room temperature. The effects of SSPS amounts on the thickness, air permeability and water vapor permeability of the crust leather were studied. The tensile properties of the leathers filled by SSPS were analyzed. The results indicated that with increasing the amounts of SSPS, the thickness and the water vapor permeability of the leathers increase, while the air permeability decreases slightly. The maximum stress-strain capacity of leathers decreases with increasing the SSPS amount. At the SSPS amount of 3%, the leather is good in softness, as well as in physical and mechanical properties. Take-Away: 1.SSPS from soybean dregs is an acidic polysaccharide, which is rich in raw materials and low in cost. 2.Leathers filled with SSPS have good performance.

Bielinski, Clément. "Impact of the flow on mass transfer from particles : biomedical applications." Thesis, Compiègne, 2021. https://bibliotheque.utc.fr/Default/doc/SYRACUSE/2021COMP2630.

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Le transfert de masse à partir de particules présente de nombreuses applications biomédicales, telles que le relargage contrôlé de médicaments, la culture cellulaire, ou encore la conception d’organes bioartificiels. En conditions opérationnelles, les particules sont soumises à des écoulements de fluides de différentes natures, dont l’effet sur le transport du soluté est aujourd’hui encore mal connu. Dans cette thèse, nous nous intéressons à l’effet de l’écoulement sur le transfert de masse à partir de capsules et de fibres cœur-coque. Le cas du relargage d’un soluté par une fibre cœur-coque confinée dans un canal plan et soumise à un écoulement de Poiseuille est étudié à partir de simulations numériques en deux dimensions basées sur la méthode de Boltzmann sur réseau. Les effets combinés de l’écoulement et de la présence de la coque sur le transfert de masse sont analysés sur une large plage de nombre de Reynolds couvrant des écoulements stationnaires et instationnaires. Une corrélation donnant le nombre de Sherwood (le coefficient de transfert de masse adimensionnel) en fonction de la perméabilité de la coque, du nombre de Reynolds, et du nombre de Schmidt est proposée. La perméabilité de la coque est une propriété difficilement mesurable. Les méthodes actuelles de caractérisation ne permettent d’obtenir qu’une perméabilité effective pour l’ensemble de la particule (cœur et coque réunis), et non spécifiquement pour la coque. Une nouvelle méthode de caractérisation est proposée et validée sur des données numériques et expérimentales. Cette méthode consiste à extraire la perméabilité de la capsule par analyse inverse, en ajustant les courbes de relargage avec des solutions de la seconde loi de Fick calculées en une dimension par la méthode des différences finies. Le relargage d’un soluté par une capsule placée dans un écoulement de cisaillement est également analysé par des simulations tridimensionnelles couplant la méthode de Boltzmann sur réseau et la méthode des frontières immergées pour les interactions fluides-structure. L’écoulement améliore significativement l’efficacité du transfert de masse par convection forcée. L’effet des conditions aux limites à la surface de la capsule est examiné. Considérer des conditions aux limites de Dirichlet, comme fait classiquement dans la littérature, conduit à des nombres de Sherwood bien plus élevés que dans le cas de conditions aux limites de continuité, plus adaptées pour modéliser le relargage d’un soluté. La dynamique d’une suspension de capsules déformables en écoulement dans une constriction est aussi étudiée. Un diagramme d’états décrivant la transition entre le passage et le blocage de la constriction par les capsules est déterminé en fonction de leurs propriétés géométriques et mécaniques. Il peut être utilisé, par exemple, afin d’optimiser le design de systèmes microfluidiques dans le but d’améliorer l’efficacité du transfert de masse
Mass transfer from particles is encountered in many biomedical applications, such as controlled drug delivery, cell culture, or in designing bioartificial organs. In operating conditions, particles are subjected to various flows, whose effect on solute transport is still not well understood and controlled. In this PhD thesis, we study the effect of the flow on mass transfer from core-shell capsules and fibers, using numerical simulations. Solute release from a core-shell fiber confined in a channel and subjected to Poiseuille flow is studied using two-dimensional lattice Boltzmann simulations. The combined effects of the flow and the shell permeability on mass transfer are analyzed over a wide range of Reynolds number covering both steady and unsteady flows. A new correlation giving the Sherwood number (the dimensionless mass transfer coefficient) as a function of the shell permeability, the Reynolds number, and the Schmidt number is proposed. The shell permeability is difficult to measure. Current characterization methods only allow the determination of an effective permeability for the whole particle (core and shell combined), and not specifically the shell permeability. A novel method to characterize capsules shell permeability is proposed and validated on both numerical and experimental data. This method consists in extracting the capsule permeability by fitting the release curves with numerical solutions of Fick’s second law of diffusion computed in one dimension using the finite difference method, by assuming spherical symmetry. Solute release from a capsule placed in a shear flow is also analyzed by the mean of three-dimensional simulations coupling the lattice Boltzmann method and the immersedboundary method for the fluid-structure interaction. The flow is found to enhance the masstransfer efficiency by forced convection. The effect of the boundary conditions set at the surface of the capsule is examined, as well. Considering Dirichlet boundary conditions at the particle surface, as classically done in literature, leads to significantly higher Sherwood numbers as compared to the case of continuity of both the concentration and the mass flux, which is more adapted to model solute release. The suspension dynamics of soft capsules in a microfluidic constriction is also studied. A state diagram describing the transition from capsule passage to blockage is determined as a function of their geometrical and mechanical properties. It can be used, for example, to optimize the design of microfluidic devices in order to enhance the mass transfer efficiency

Colace, Gianmarco. "Modification of Poly(vinyl alcohol) film to maximize barrier properties." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/668477.

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L'alcohol polivinílic (PVA) és el polímer sintètic mes produït al món. L'excel·lent resistència química i propietats físiques de la resina del PVA han generat un ampli ús a nivell industrial. Els films d'alcohol polivinílic exhibeixen alta resistència a la tensió, resistència a l'abrasió i propietats barrera a l'oxígen, que sota en absencia d`humitat són molt superiors a la majoria d'altres polímers. Els films de PVA són àmpliament utilitzats en aplicacions d'embalatge, on la permeabilitat arriba a ser una propietat crítica a mesurar. Una àmplia sèrie de modificacions poden ser aplicades per canviar la difusió a través dels films. Per a aquest treball van ser triades dos tipus de modificacions: la barreja amb altres polímers hidrosolubles i la preparació d'un material compost. Segons Robeson, un model en sèrie de matriu i partícules, condueix a un sistema tortuós que, per un gruix donat, disminueix la permeabilitat, mentre els models de Bharadwaj per polímers barrejats van ser utilitzats per a la predicció de la permeabilitat. La producció de film es basa en l'evaporació del solvent: el polímer es dissolt i forma una solució amb una determinada concentració i viscositat; després les partícules o el segon polímer són afegits al sistema; la barreja viscosa és abocada damunt d'un suport de vidre i distribuïda manualment sobre el suport amb un ganivet aplicador regulat amb diferents distàncies. Els experiments de solubilitat van ser realitzats mesurant el temps de dissolució dels films modificats i del polímer de partida i no es van observar diferències després de les modificacions. Els experiments amb el mètode de dry cup van ser duts a terme per mesurar la permeabilitat al vapor d'aigua, registrant una disminució en els valors.
El alcohol polivinílico (PVA) es el polímero sintético más producido en el mundo. La excelente resistencia química y propiedades físicas de la resina de PVA han generado un amplio uso a nivel industrial. Los films de alcohol polivinílico exhiben alta resistencia a la tensión, resistencia a la abrasión y propiedades barrera al oxígeno, que en absencia de humedad son muy superiores a la de la mayoría de polímeros. Los films de PVA son ampliamente utilizados en aplicaciones de embalaje, donde la permeabilidad llega a ser una propiedad crítica a medir. Una amplia serie de modificaciones pueden ser aplicadas para cambiar la difusión a través de los films. Para este trabajo fueron elegidas dos tipos de modificaciones: la mezcla con otros polímeros hidrosolubles y la preparación de un material compuesto. Según Robeson, un modelo en serie de matriz y partículas conduce a un sistema tortuoso que, para un espesor dado, disminuye la permeabilidad, mientras los modelos de Bharadwaj para mezclas de polímeros fueron utilizados para la predicción de la permeabilidad. La producción de film se basa en la evaporación del solvente: el polímero se disuelve y forma una solución con una determinada concentración y viscosidad; luego las partículas o el segundo polímero son añadidos al sistema; la mezcla viscosa es vertida encima de un soporte de vidrio y distribuida manualmente sobre el soporte con una cuchilla aplicador regulado con diferentes distancias. Los experimentos de solubilidad fueron realizados midiendo el tiempo de disolución de los films modificados y del polímero de partida y no se observaron diferencias después de las modificaciones. Los experimentos con el método de dry cup fueron llevados a cabo para medir la permeabilidad al vapor de agua, registrando una disminución en los valores.
Poly(vinyl alcohol) (PVA), a polyhydroxy polymer, is the largest volume, synthetic water-soluble polymer produced in the world. The excellent chemical resistance and physical properties of PVA resins have resulted in broad industrial use. Poly(vinyl alcohol) films exhibit high tensile strength, abrasion resistance, and oxygen barrier properties which under dry conditions are superior to those of most polymers. PVA films are broadly used in packaging applications, where permeability became a critical property to evaluate. A wide range of modifications can be applied to change the moisture diffusion through the film; two types were chosen for the work: blending with other water-soluble polymers and preparation of a composite. According to Robeson, a series model of polymeric matrix and particles, leads to a tortuous system, which, for a given thickness, decreases the permeability, meanwhile Bharadwaj models for blended polymer were used for permeability prediction. The film casting is based on solvent evaporation: the polymer is dissolved and forms a solution with a certain concentration and viscosity; then the particles or the second water-soluble polymer are loaded in the system; the viscous mixture is poured on a glass support and spread across it manually with a casting knife set at different gaps. So, the wet film is left to stand to evaporate the solvent and leave a dry film. Solubility experiments were performed, by measuring the dissolution time of the film, and it was not significantly influenced by the material modification. Dry cup method experiments were run to measure the water vapor permeability, recording a decreasing values of permeabilities.

Sobecki, Nicolas. "Upscaling of Thermodynamic Properties for Flow Simulation in Low Permeability Unconventional Reservoirs." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS005/document.

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Les réservoirs de type "tight oil" et "shale gaz" ont une partie importante de leur volume poreux occupée par des micropores (< 2nm) et des mesopores (entre 2 et 50 nm). Ce type d'environnement crée de fortes forces d’interaction dans le fluide confiné avec les parois du pores et entre ses propres molécules, ce qui change fortement la thermodynamique du fluide. Un travail important doit donc être effectué sur le développement de méthodes de mise à l'échelle de la distribution de pore pour effectuer des simulations réservoir à grande échelle. Premièrement, des simulations moléculaires sont effectuées sur des fluides confinés afin d'obtenir des propriétés thermodynamiques de référence à l'équilibre liquide/vapeur pour différentes tailles de pore. Ensuite, une comparaison des données de simulation moléculaire avec les résultats issus des équation d'état utilisées dans la littérature a permis de mettre en valeur la méthode de flash avec pression capillaire et changement du point critique comme la meilleure méthode existante pour décrire la physique du fluide confiné. Des simulations fines d'écoulement matrice/fracture ont donc été effectuées pour différentes tailles de pore. Des modèles de mise à l'échelle en maillage grossier ont été ensuite construits à partir du même cas synthétique et les résultats ont été comparés avec ceux des simulations de référence en maillage fin. Un nouveau modèle de triple porosité considérant fracture, petit pores et grand pores avec une approche MINC a donné des résultats très proches du maillage fin. Finalement un réservoir stimulé hydrauliquement à grande échelle a été simulé pour différentes distributions de pores avec le modèle développé
Tight oil and shale gas reservoirs have a significant part of their pore volume occupied by micro (below 2nm) and mesopores (between 2 and 50nm). This kind of environment creates strong interaction forces in the confined fluid with pore walls as well as between its own molecules and then changes dramatically the fluid phase behavior. An important work has therefore to be done on developing upscaling methodology of the pore size distribution for large scale reservoir simulations. Firstly, molecular simulations are performed on different confined fluids in order to get reference thermodynamic properties at liquid/vapor equilibrium for different pore sizes. Then, the comparison with commonly used modified equation of state (EOS) in the literature highlighted the model of flash with capillary pressure and critical temperature and pressure shift as the best one to match reference molecular simulation results. Afterwards fine grid matrix/fracture simulations have been built and performed for different pore size distributions. Then, coarse grid upscaling models have then been performed on the same synthetic case and compared to the reference fine grid results. A new triple porosity model considering fracture, small pores and large pores with MINC (Multiple Interacting Continua) approach, has shown very good match with the reference fine grid results. Finally a large scale stimulated reservoir volume with different pore size distribution inside the matrix has been built using the upscaling method developed here

Wang, Zhenyu. "Rôle de l’adénylate cyclase soluble, de phosphodiesterases et d’Epac dans la fonction mitochondriale cardiaque et la mort cellulaire." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS186/document.

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L’AMPc est un messager important de la régulation neurohormonale du cœur. En activant ses effecteurs, l’AMPc régule de nombreuses fonctions cellulaires telles que l'expression de gènes, le couplage excitation-contraction et le métabolisme cellulaire. Chez les mammifères, l'AMPc est produit par une famille d’adénylate cyclases au sein de plusieurs compartiments subcellulaires solubles ou membranaires. L'existence et le rôle de la signalisation des nucléotides cycliques dans les mitochondries ont été postulés, mais n'ont pas encore été démontrés. De plus, son implication dans la régulation de la mort cellulaire est encore inconnue. Dans cette thèse, nous avons démontré l'expression locale de plusieurs acteurs de la signalisation de l'AMPc dans les mitochondries cardiaques, à savoir une forme tronquée soluble AC (sACt) et la protéine d'échange directement activées par AMPc 1 (Epac1). Nous avons montré un rôle protecteur pour sACt contre la mort cellulaire, l'apoptose, ainsi que la nécrose de cardiomyocytes primaires. Lors de la stimulation par du bicarbonate (HCO3-) et du Ca2+, la sACt produit de l’AMPc, qui à son tour stimule la consommation d'oxygène, une augmentation du potentiel mitochondrial de membrane (ΔΨm) et la production d'ATP. L’AMPc est limitant pour l’entrée matricielle de Ca2+ via l’uniport calcique mitochondrial (MCU) et, en conséquence, prévient la transition de perméabilité mitochondriale (MPT). En outre, dans les mitochondries isolées de cœurs de rats défaillants, la stimulation de la voie de l'AMPc par le HCO3- prévient la sensibilisation des mitochondries au Ca2+. Nous avons également constaté que les familles de phosphodiestérases (PDE), PDE2, 3 et 4, sont exprimées dans les mitochondries cardiaques régulant le taux d’AMPc. Ainsi, ces protéines forment une voie de signalisation locale dans la matrice régulant la fonction mitochondriale cardiaque. Finalement, notre étude a permis d’identifier un lien entre l'AMPc mitochondrial, le métabolisme, certaines PDEs et la mort cellulaire dans le cœur, qui est indépendant de la signalisation AMPc cytosolique. Ceci pourrait constituer un nouveau mécanisme cardioprotecteur via la préservation de la fonction mitochondriale dans un contexte physiopathologique
CAMP is an important messenger in neurohormonal regulation of the heart. By activating its effectors, cAMP regulates many cellular functions such as gene expression, excitation-contraction coupling and cellular metabolism. In mammals, cAMP is produced by a family of adenylyl cyclase with various subcellular locations and membrane anchorage. The existence and role of cyclic nucleotide signaling in mitochondria has been postulated, but has not yet been demonstrated. Moreover, its implication in the regulation of cell death is still unknown. In this thesis, we demonstrated the local expression of several actors of cAMP signaling within cardiac mitochondria, namely a truncated form of soluble AC (sACt) and the exchange protein directly activated by cAMP 1 (Epac1) and showed a protective role for sACt against cell death, apoptosis as well as necrosis, in primary cardiomyocytes. Upon stimulation with bicarbonate (HCO3-) and Ca2+, sACt produces cAMP, which in turn stimulates oxygen consumption, increased the mitochondrial membrane potential (∆Ψm) and ATP production. cAMP is rate-limiting for matrix Ca2+ entry via the mitochondrial calcium uniporter (MCU) and, as a consequence, prevented mitochondrial permeability transition (MPT). In addition, in mitochondria isolated from failing rat hearts, stimulation of the mitochondrial cAMP pathway by HCO3- rescued the sensitization of mitochondria to Ca2+-induced MPT. We also found that PDE2, 3 and 4 families are located in cardiac mitochondria. They form a local signaling pathway with soluble AC in the matrix, which regulates cardiac mitochondrial functions. Thus, our study identifies a link between mitochondrial cAMP, mitochondrial metabolism, some PDEs and cell death in the heart, which is independent of cytosolic cAMP signaling. This might constitute a novel cardioprotective mechanism through mitochondrial function preservation in pathophysiological conditions

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Книги з теми "Solute permeability":

Bundschuh, Jochen. Introduction to the numerical modeling of groundwater and geothermal systems: Fundamentals of mass, energy, and solute transport in poroelastic rocks. Boca Raton: CRC Press, 2010.

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Polishchuk, Alexandre Ya. Multicomponent transport in polymer systems for controlled release. Australia: Gordon and Breach Science publishers, 1997.

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Polishchuk, Alexandre Ya. Multicomponent transport in polymer systems for controlled release. Amsterdam, The Netherlands: Gordon and Breach Science, 1997.

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Water and Solute Permeability of Plant Cuticles. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-68945-4.

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Water And Solute Permeability Of Plant Cuticles Measurement And Data Analysis. Springer, 2009.

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1955-, Roth Kurt, ed. Field-scale water and solute flux in soils. Basel: Birkhäuser Verlag, 1990.

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Soil-water-solute process characterization: An integrated approach. Boca Raton: CRC Press, 2005.

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Kulasiri, Don, and Wynand Verwoerd. Stochastic Dynamics: Modeling Solute Transport in Porous Media (North-Holland Series in Applied Mathematics and Mechanics). North Holland, 2002.

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(Editor), Javier Alvarez-Benedi, and Rafael Munoz-Carpena (Editor), eds. Soil-Water-Solute Process Characterization: An Integrated Approach. CRC, 2004.

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Selim, H. Magdi. Contaminants Transport in Soils: Principles and Applications. Taylor & Francis Group, 2014.

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Частини книг з теми "Solute permeability":

Cooper, Gordon J., Ram Dixit, June Nasrallah, and Walter F. Boron. "The Permeability of MIPS to Gases." In Molecular Biology and Physiology of Water and Solute Transport, 275–82. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-1203-5_38.

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Volobuyeva, Olga V., Ludmila P. Khokhlova, Gennady A. Velikanov, and Oleg A. Opanasyuk. "Genotypically Determined Actin-Regulated Water Permeability of Two Plasmodematal Transport Channels." In Molecular Biology and Physiology of Water and Solute Transport, 347–56. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-1203-5_47.

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Mathai, John C., and Mark L. Zeidel. "Measurement of Water and Solute Permeability by Stopped-Flow Fluorimetry." In Methods in Membrane Lipids, 323–32. Totowa, NJ: Humana Press, 2007. http://dx.doi.org/10.1007/978-1-59745-519-0_21.

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Wang, Chi-Yuen, and Michael Manga. "Groundwater Flow and Transport." In Lecture Notes in Earth System Sciences, 9–22. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-64308-9_2.

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AbstractWe summarize the basic principles of, and governing equations for, groundwater flow and transport. Topics covered include the concepts of pressure and hydraulic head, Darcy’s law, permeability, and storage. We compare saturated and unsaturated flow. We provide an introduction to heat and solute transport.

Barrieu, François, Raphael Morillon, and Maarten J. Chrispeels. "Modulation of Aquaporin Gene Expression in Arabidopsis Leads to Altered Membrane Water Permeability." In Molecular Biology and Physiology of Water and Solute Transport, 255–59. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-1203-5_35.

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Luther, Emmanuel E., Seyed M. Shariatipour, Michael C. Dallaston, and Ran Holtzman. "Solute Driven Transient Convection in Layered Porous Media." In Springer Proceedings in Energy, 3–9. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63916-7_1.

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AbstractCO2 geological sequestration has been proposed as a climate change mitigation strategy that can contribute towards meeting the Paris Agreement. A key process on which successful injection of CO2 into deep saline aquifer relies on is the dissolution of CO2 in brine. CO2 dissolution improves storage security and reduces risk of leakage by (i) removing the CO2 from a highly mobile fluid phase and (ii) triggering gravity-induced convective instability which accelerates the downward migration of dissolved CO2. Our understanding of CO2 density-driven convection in geologic media is limited. Studies on transient convective instability are mostly in homogeneous systems or in systems with heterogeneity in the form of random permeability distribution or dispersed impermeable barriers. However, layering which exist naturally in sedimentary geological formations has not received much research attention on transient convection. Therefore, we investigate the role of layering on the onset time of convective instability and on the flow pattern beyond the onset time during CO2 storage. We find that while layering has no significant effect on the onset time, it has an impact on the CO2 flux. Our findings suggest that detailed reservoir characterisation is required to forecast the ability of a formation to sequester CO2.

Devuyst, Olivier, Sophie Combet, Jean-Luc Balligand, Eric Goffin, and Jean-Marc Verbavatz. "Expression and Regulation of Aquaporin-1 and Endothelial Nitric Oxide Synthase in Relationship with Water Permeability Across the Peritoneum." In Molecular Biology and Physiology of Water and Solute Transport, 69–75. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-1203-5_10.

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Larsen, Erik Hviid, and Jens Nørkær Sørensen. "Stationary and Nonstationary Ion and Water Flux Interactions in Kidney Proximal Tubule: Mathematical Analysis of Isosmotic Transport by a Minimalistic Model." In Reviews of Physiology, Biochemistry and Pharmacology, 101–47. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/112_2019_16.

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AbstractOur mathematical model of epithelial transport (Larsen et al. Acta Physiol. 195:171–186, 2009) is extended by equations for currents and conductance of apical SGLT2. With independent variables of the physiological parameter space, the model reproduces intracellular solute concentrations, ion and water fluxes, and electrophysiology of proximal convoluted tubule. The following were shown: Water flux is given by active Na+ flux into lateral spaces, while osmolarity of absorbed fluid depends on osmotic permeability of apical membranes. Following aquaporin “knock-out,” water uptake is not reduced but redirected to the paracellular pathway. Reported decrease in epithelial water uptake in aquaporin-1 knock-out mouse is caused by downregulation of active Na+ absorption. Luminal glucose stimulates Na+ uptake by instantaneous depolarization-induced pump activity (“cross-talk”) and delayed stimulation because of slow rise in intracellular [Na+]. Rate of fluid absorption and flux of active K+ absorption would have to be attuned at epithelial cell level for the [K+] of the absorbate being in the physiological range of interstitial [K+]. Following unilateral osmotic perturbation, time course of water fluxes between intraepithelial compartments provides physical explanation for the transepithelial osmotic permeability being orders of magnitude smaller than cell membranes’ osmotic permeability. Fluid absorption is always hyperosmotic to bath. Deviation from isosmotic absorption is increased in presence of glucose contrasting experimental studies showing isosmotic transport being independent of glucose uptake. For achieving isosmotic transport, the cost of Na+ recirculation is predicted to be but a few percent of the energy consumption of Na+/K+ pumps.

Egan, Edmund A. "Effect of Lung Inflation on Alveolar Permeability to Solutes." In Ciba Foundation Symposium 38 - Lung Liquids, 101–24. Chichester, UK: John Wiley & Sons, Ltd., 2008. http://dx.doi.org/10.1002/9780470720202.ch7.

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Fink, M. P. "Alterations in Gastrointestinal Barrier Function in Sepsis: The Effect of Lipopolysaccharide on Mucosal Permeability to Hydrophilic Solutes." In Yearbook of Intensive Care and Emergency Medicine, 248–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-84734-9_24.

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Тези доповідей конференцій з теми "Solute permeability":

Sciortino, Antonella, Feike J. Leij, and Nobuo Toride. "Solute Transport in Dual-Permeability Porous Media." In World Environmental And Water Resources Congress 2012. Reston, VA: American Society of Civil Engineers, 2012. http://dx.doi.org/10.1061/9780784412312.017.

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Wei Yuan, Yonggang Lv, Min Zeng, and Bingmei M. Fu. "Non-invasive measurement of solute permeability of rat pial microvessels." In 2007 IEEE 33rd Annual Northeast Bioengineering Conference. IEEE, 2007. http://dx.doi.org/10.1109/nebc.2007.4413340.

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Katkov, Igor I. "Bi-Phasic Reverse Movement of Permeable Solute(s) in Cells is Predicted by the Relativistic Permeability Approach." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80008.

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Ternary systems water — impermeable solute (“salts”) — permeable solute have been widely used in cryopreservation of biological cells where the permeable solute is the cryoprotective agent (CPA). The cell membrane is considered “leaky”’ to CPA so the osmotic process is described by a system of two coupled non-linear equations: the osmotic equation (1.1) that drives water against the gradient of total osmotic pressure of both solutes, and the diffusion equation (1.2), which drives the permeable solute towards its gradient across membrane. In case of the “classical” system one permeable solute + impermeable entities (“salts”), the third equation (Boyle-van’t Hoff law (1.3) that states the constant amount of the impermeable components inside the cell (3) is added: (1.1)dWdt=-LpRTYf-Y+Zf-Z(1.2)dXdt=PsAYf-Y(1.3)WZ=WisoZiso=W0Z0=WfZf=const where W is the cell water volume, t is the time, Lp is the hydraulic conductivity, R is the gas constant, T is the temperature, A is the surface area, Y and Z are the osmolalities of permeable and impermeable solutes respectively, X ≡ WY is the intracellular amount (“number of osmoles”) of the permeable solute, Ps is the solute membrane permeability. Subscript “iso” refers to the isosmotic values, “0” is the values at time zero, and “f” refers to the final (equilibrium, extracellular) values. The water permeability can be considered as LpRT.

Gu, Wei Yong, and Hai Yao. "Constitutive Modeling of Solute Diffusivity in Hydrated Soft Tissues." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59833.

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Based on the experimental results of electrical conductivity and hydraulic permeability, a new constitutive model for relative diffusivity (D/Do) of solutes in gels and tissues was developed. This model could predict the functional relationship between solute diffusivity and tissue deformation. This model could also quantitatively predict the effect of solute size on solute diffusivity in tissues. This study is important for the understanding of nutritional transport in cartilaginous tissues. It is also useful for the prediction of nutrition levels in tissue constructs during growth.

Fu, Bingmei M., Roger H. Adamson, and Fitz-Roy E. Curry. "In Vivo Measurement of Microvessel Permeability and Tissue Diffusion Coefficient in Frog Mesentery by Confocal Microscopy." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0599.

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Abstract Our early studies showed that tissue diffusion coefficient (Dt) of small solute sodium fluorescein (0.45 nm radius) in frog mesentery is 30% of its free diffusion coefficient (Dfree) in aqueous solution. We test here the hypothesis that because of its size-limiting structure the interstitium would provide larger resistance to larger solute α-lactalbumin (2.0 nm radius). We extended our previous method by using laser-scanning confocal microscopy to measure both solute capillary permeability (P) and solute tissue diffusion coefficients (Dt) from the rate of tissue solute accumulation and the radial concentration gradients around individually perfused microvessels in frog mesentery. pα-lactalbumin was 1.7 ± 0.7 (SD) × 10−6 cm/s (n = 6). Dt/Dfree was 27% ± 5% (SD) (n = 6). This value is comparable to that for small solute sodium fluorescein. Our results indicate that frog mesenteric interstitium is less selective to larger solute α-lactalbumin than the microvessel wall.

Huang, Zhonping, Anil C. Attaluri, Amit Belwalkar, William Van Geertruyden, Dayong Gao, and Wojciech Misiolek. "An Experimental Study of Transport Properties of Ceramic Membranes for Use in Hemodialysis." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192808.

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Hemodialysis (HD) remains the primary treatment modality for the management of renal failure patients. Hemodialysis membranes play an important role in renal replacement therapy (RRT). HD is an extracorporeal blood clean process where the major mass transfer mechanism is diffusion. This therapy is mainly effectual for low molecular weight (LMW) solutes (such as urea and creatinine) removal or clearance for which diffusive mass transfer is a swift process. There is an increase in the removal of middle molecular weight (MMW) solutes (such as β2-microglobulin) when high flux membranes are available. Hemodiafiltration (HDF) is a treatment where the convective mass transfer accolades with diffusive mass transfer to increase the solute clearance efficacy, specifically for MMW solutes. The convective mass transfer is reliant on the amount of fluid exchanged. Toxin removal efficiency of HDF significantly depends on the porosity, pore size, pore distribution and surface area of the membrane [1, 2]. Although newly developed high flux polysulfone membranes have high MMW solute clearance, the non-uniform pore size and pore distribution is the main contributors to the albumin loss. Previous studies by Huang et al.[3], showed that nanoporous alumina sheet membranes have uniform pore size (∼ 10nm), high hydraulic permeability, uniform pore distribution and excellent pore structure with uniform channels. It was predicted that these membranes would have high molecular removal capacity. Therefore, in this study, experiments were performed to generate the data of intrinsic membrane properties such as hydraulic permeability, sieving coefficient and solute diffusive permeability for the alumina tubular membranes. Results were also compared to current polyethersulfone (PES) dialysis membranes.

Huang, Lining, James D. Benson, and Mahmoud Almasri. "A microfluidic sensor for evaluation of solute and solvent membrane permeability in individual cells." In 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS). IEEE, 2017. http://dx.doi.org/10.1109/transducers.2017.7994093.

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Shin, Da Wi, Niranjan Khadka, Jie Fan, Marom Bikson, and Bingmei M. Fu. "Transcranial direct current stimulation transiently increases the blood-brain barrier solute permeability in vivo." In SPIE Medical Imaging, edited by Barjor Gimi and Andrzej Krol. SPIE, 2016. http://dx.doi.org/10.1117/12.2218197.

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Zhou, Xiaozhou, John E. Novotny, and Liyun Wang. "Modeling Fluorescence Recovery After Photobleaching in Cyclically Loaded Bone: Potential Application in Quantitatively Measuring Load-Induced Solute Flows." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-193018.

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Recent experiments strongly suggest that osteocytes, the most numerous bone cells, play much more active roles in bone adaptation and metabolism [1]. These multifunctioning cells are found to detect external mechanical stimuli, and to release soluable agents that modulate the functioning of other cell types [1, 2]. Solute transport around osteocytes through the bone lacunar-canalicular system (LCS), especially via load-induced convection, is critical for osteocyte viability and proper functioning. However, despite of significant advance in elucidating the LCS microstructure, permeability, and the molecular sieving properties [3–5], the fundamental mechanisms of solute transport around osteocytes still remain poorly understood, and solute flows have not been quantified in vivo.

Chen, Baoming, Fang Liu, Aimin Liu, and Wenguang Geng. "Influence of Interfacial Effect Between a Porous Wall and an Air Region on Natural Convection." In ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82234.

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VOCs natural convective flow driven by thermo, solute and humidity buoyancy forces from a porous wall to indoor room was studied numerically in this paper, including coupled diffusion effects by three gradients interactions. The physical model for the fluid flow made use of Brinkman-Forchheimer extended Darcy equation in the porous wall and Navier-Stokes equation in the clear region. Finite element method was used to solve governing equations. Effect of interface at the interface on flow, heat and mass transfer was studied, which varied with stress jump coefficient β and permeability. The results showed that flow velocity varied greatly with increase of coefficient β in the boundary. Decrease in the value of dimensionless permeability Da also had influence on velocity variation at the interface. However, there are little influence of interface on the distribution of temperature and concentration in the whole region.

Звіти організацій з теми "Solute permeability":

Snadra L. Fox, X. Xie, K. D. Schaller, E. P. Robertson, and G. A. Bala. Permeability Modification Using a Reactive Alkaline-Soluble Biopolymer. Office of Scientific and Technical Information (OSTI), October 2003. http://dx.doi.org/10.2172/910609.

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Cesar, J. R., and O. H. Ardakani. Organic geochemistry of the Montney Formation: new insights about the source of hydrocarbons, their accumulation history and post accumulation processes. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329788.

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This study consists of a non-traditional molecular and stable isotope approach to analyze organic matter (soluble bitumen and produced oil/condensate) from the Montney Formation low-permeability reservoirs, with the purpose of identifying source(s) of hydrocarbons, accumulation history and post accumulation processes. The same approach bases on the distribution of compound classes such as aromatic carotenoids, polycyclic aromatic hydrocarbons (PAHs), bicyclic alkanes, and oxygen-polar compounds. The geochemical screening has been enhanced with performing compound specific isotope analysis (CSIA) of n-alkanes and selected aromatic hydrocarbons. Widely spread PAHs, the presence of molecular indicators of euxinia, and hydrocarbon mixtures identified using CSIA profiles, are some of the key findings from this research, which will improve our understanding of the Montney petroleum system(s).

Russo, David, Daniel M. Tartakovsky, and Shlomo P. Neuman. Development of Predictive Tools for Contaminant Transport through Variably-Saturated Heterogeneous Composite Porous Formations. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7592658.bard.

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The vadose (unsaturated) zone forms a major hydrologic link between the ground surface and underlying aquifers. To understand properly its role in protecting groundwater from near surface sources of contamination, one must be able to analyze quantitatively water flow and contaminant transport in variably saturated subsurface environments that are highly heterogeneous, often consisting of multiple geologic units and/or high and/or low permeability inclusions. The specific objectives of this research were: (i) to develop efficient and accurate tools for probabilistic delineation of dominant geologic features comprising the vadose zone; (ii) to develop a complementary set of data analysis tools for discerning the fractal properties of hydraulic and transport parameters of highly heterogeneous vadose zone; (iii) to develop and test the associated computational methods for probabilistic analysis of flow and transport in highly heterogeneous subsurface environments; and (iv) to apply the computational framework to design an “optimal” observation network for monitoring and forecasting the fate and migration of contaminant plumes originating from agricultural activities. During the course of the project, we modified the third objective to include additional computational method, based on the notion that the heterogeneous formation can be considered as a mixture of populations of differing spatial structures. Regarding uncertainly analysis, going beyond approaches based on mean and variance of system states, we succeeded to develop probability density function (PDF) solutions enabling one to evaluate probabilities of rare events, required for probabilistic risk assessment. In addition, we developed reduced complexity models for the probabilistic forecasting of infiltration rates in heterogeneous soils during surface runoff and/or flooding events Regarding flow and transport in variably saturated, spatially heterogeneous formations associated with fine- and coarse-textured embedded soils (FTES- and CTES-formations, respectively).We succeeded to develop first-order and numerical frameworks for flow and transport in three-dimensional (3-D), variably saturated, bimodal, heterogeneous formations, with single and dual porosity, respectively. Regarding the sampling problem defined as, how many sampling points are needed, and where to locate them spatially in the horizontal x₂x₃ plane of the field. Based on our computational framework, we succeeded to develop and demonstrate a methdology that might improve considerably our ability to describe quntitaively the response of complicated 3-D flow systems. The results of the project are of theoretical and practical importance; they provided a rigorous framework to modeling water flow and solute transport in a realistic, highly heterogeneous, composite flow system with uncertain properties under-specified by data. Specifically, they: (i) enhanced fundamental understanding of the basic mechanisms of field-scale flow and transport in near-surface geological formations under realistic flow scenarios, (ii) provided a means to assess the ability of existing flow and transport models to handle realistic flow conditions, and (iii) provided a means to assess quantitatively the threats posed to groundwater by contamination from agricultural sources.

Fallik, Elazar, Robert Joly, Ilan Paran, and Matthew A. Jenks. Study of the Physiological, Molecular and Genetic Factors Associated with Postharvest Water Loss in Pepper Fruit. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7593392.bard.

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The fruit of pepper (Capsicum annuum) commonly wilts (or shrivels) during postharvest storage due to rapid water loss, a condition that greatly reduces its shelf life and market value. The fact that pepper fruit are hollow, and thus have limited water content, only exacerbates this problem in pepper. The collaborators on this project completed research whose findings provided new insight into the genetic, physiological, and biochemical basis for water loss from the fruits of pepper (Capsicum annuum and related Capsicum species). Well-defined genetic populations of pepper were used in this study, the first being a series of backcross F₁ and segregating F₂, F₃, and F₄ populations derived from two original parents selected for having dramatic differences in fruit water loss rate (very high and very low water loss). The secondly population utilized in these studies was a collection of 50 accessions representing world diversity in both species and cultivar types. We found that an unexpectedly large amount of variation was present in both fruit wax and cutin composition in these collections. In addition, our studies revealed significant correlations between the chemical composition of both the fruit cuticular waxes and cutin monomers with fruit water loss rate. Among the most significant were that high alkane content in fruit waxes conferred low fruit water loss rates and low permeability in fruit cuticles. In contrast, high amounts of terpenoids (plus steroidal compounds) were associated with very high fruit water loss and cuticle permeability. These results are consistent with our models that the simple straight chain alkanes pack closely together in the cuticle membrane and obstruct water diffusion, whereas lipids with more complex 3-dimensional structure (such as terpenoids) do not pack so closely, and thus increase the diffusion pathways. The backcross segregating populations were used to map quantitative trait loci (QTLs) associated with water loss (using DART markers, Diversity Arrays Technology LTD). These studies resulted in identification of two linked QTLs on pepper’s chromosome 10. Although the exact genetic or physiological basis for these QTLs function in water loss is unknown, the genotypic contribution in studies of near-isogenic lines selected from these backcross populations reveals a strong association between certain wax compounds, the free fatty acids and iso-alkanes. There was also a lesser association between the water loss QTLs with both fruit firmness and total soluble sugars. Results of these analyses have revealed especially strong genetic linkages between fruit water loss, cuticle composition, and two QTLs on chromosome 10. These findings lead us to further speculate that genes located at or near these QTLs have a strong influence on cuticle lipids that impact water loss rate (and possibly, whether directly or indirectly, other traits like fruit firmness and sugar content). The QTL markers identified in these studies will be valuable in the breeding programs of scientists seeking to select for low water loss, long lasting fruits, of pepper, and likely the fruits of related commodities. Further work with these newly developed genetic resources should ultimately lead to the discovery of the genes controlling these fruit characteristics, allowing for the use of transgenic breeding approaches toward the improvement of fruit postharvest shelf life.