Increase In Water Permeability Research Articles

Membrane Cholesterol Reduces Polymyxin B Nephrotoxicity in Renal Membrane Analogs

Polymyxin B (PmB) is a “last-line” antibiotic scarcely used due to its nephrotoxicity. However, the molecular basis for antibiotic nephrotoxicity is not clearly understood. We prepared kidney membrane analogs of detergent-susceptible membranes, depleted of cholesterol, and cholesterol enriched, resistant membranes. In both analogs, PmB led to membrane damage. By combining x-ray diffraction, molecular dynamics simulations, and electrochemistry, we present evidence for two populations of PmB molecules: peptides that lie flat on the membranes, and an inserted state. In cholesterol depleted membranes, PmB forms clusters on the membranes leading to an indentation of the bilayers and increase in water permeation. The inserted peptides formed aggregates in the membrane core leading to further structural instabilities and increased water intake. The presence of cholesterol in the resistant membrane analogs led to a significant decrease in membrane damage. Although cholesterol did not inhibit peptide insertion, it minimized peptide clustering and water intake through stabilization of the bilayer structure and suppression of lipid and peptide mobility.

Effect of aggregate exposing and curing agent on the performance of exposed aggregate concrete

As the most important part of exposed aggregate concrete (EAC), the surface zone usually attracts much attention. This paper presents an investigation on the effect of aggregate exposing and curing agent on the properties and microstructure of EAC by a range of analytical techniques. The results show that a gradual reduction of compressive strength, a significant increase of abrasion resistance, obvious increase of carbonation depth and slight increase of chloride & water permeability are observed when the surface aggregates are exposed. The chloride permeability, water permeability and carbonation depth are reduced, and compressive strength and abrasion resistance of EAC are significantly enhanced by applying the curing agent. The microhardness of surface zone around aggregate is lower than that of matrix after aggregate exposing, but can be significantly increased by curing agent. The surface zone is deteriorated after exposing aggregate, but the surface zone and near-surface zone become denser after applying the curing agent. The curing agent penetrates into the concrete by 4–5mm and reacts with hydration products. The mechanical properties and durability of EAC are improved due to the increase of hydration degree and formation of new products such as CaSiO3 by application of curing agent.

Influence of the intermediate sowings of fodder crops on the agrophysical indicators of the irrigated soils in Azerbaijan dry subtropics

The findings of the studies on the influence of intermediate crops' sowings in double or triple harvests fields system on the agrophysical indicators of Irragri Gipsic calcisols and Irragri Kastanozems in dry subtropics of Azerbaijan are presented. The optimum variant that provides the greatest supply of plant residues to the soil (18.50 and 19.69 t/ha) and the improvement of agrophysical indicators of the studied soils— decrease of bulk density, improvement of particle density, increase of total porosity and water permeability, increase of the coefficient of structural properties in comparison with other variants, and also enhancement of the food potential in this part of the republic—was established.

Aquaporins facilitate hydrogen peroxide entry into guard cells to mediate ABA- and pathogen-triggered stomatal closure

Stomatal movements are crucial for the control of plant water status and protection against pathogens. Assays on epidermal peels revealed that, similar to abscisic acid (ABA), pathogen-associated molecular pattern (PAMP) flg22 requires the AtPIP2;1 aquaporin to induce stomatal closure. Flg22 also induced an increase in osmotic water permeability (Pf) of guard cell protoplasts through activation of AtPIP2;1. The use of HyPer, a genetic probe for intracellular hydrogen peroxide (H2O2), revealed that both ABA and flg22 triggered an accumulation of H2O2 in wild-type but not pip2;1 guard cells. Pretreatment of guard cells with flg22 or ABA facilitated the influx of exogenous H2O2 Brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) and open stomata 1 (OST1)/Snf1-related protein kinase 2.6 (SnRK2.6) were both necessary to flg22-induced Pf and both phosphorylated AtPIP2;1 on Ser121 in vitro. Accumulation of H2O2 and stomatal closure as induced by flg22 was restored in pip2;1 guard cells by a phosphomimetic form (Ser121Asp) but not by a phosphodeficient form (Ser121Ala) of AtPIP2;1. We propose a mechanism whereby phosphorylation of AtPIP2;1 Ser121 by BAK1 and/or OST1 is triggered in response to flg22 to activate its water and H2O2 transport activities. This work establishes a signaling role of plasma membrane aquaporins in guard cells and potentially in other cellular context involving H2O2 signaling.

Effect of ZIF-71 Particle Size on Free-Standing ZIF-71/PDMS Composite Membrane Performances for Ethanol and 1-Butanol Removal from Water through Pervaporation

This paper reports the effects of synthesis time, temperature, and reactant ratio on ZIF-71 particle size and the effect of particle size on membrane performance. Temperature has the greatest effect on particle size, as the synthesis temperature varies from −20 °C to 35 °C. The synthesized ZIF-71 has particle diameters ranging from 150 nm to 1 μm. ZIF-71 particle size is critical in ZIF-71/PDMS composite membrane performance for ethanol and 1-butanol removal from water through pervaporation. The membranes that are made with micrometer-sized ZIF-71 particles exhibit higher alcohol/water selectivity than those with smaller particles. Both alcohol and water permeability increase when larger-sized ZIF-71 particles are incorporated, because the pathways through the membranes are less tortuous.

Polyamide/nitrogen-doped graphene oxide quantum dots (N-GOQD) thin film nanocomposite reverse osmosis membranes for high flux desalination

Thin film nanocomposite (TFN) has been shown as a promising platform to further increase water permeability of commercial polyamide membrane in reverse osmosis (RO) desalination. Identification of novel and effective nano-additives, which are significantly smaller than the typical thickness of polyamide membranes (~200nm) and can be facilely incorporated into the interfacial polymerization (IP) process, is crucial to pursue this route. In this study, we prepared nitrogen-doped graphene oxide quantum dots (N-GOQD) and for the first time, fabricated polyamide/N-GOQD TFN membranes by IP for RO desalination application. We found adding only 0.02wt/v% N-GOQD into polyamide membrane drastically increased water permeability by approximately 3 times, while maintaining similar salt rejection as the pristine polyamide membrane. Enhanced water permeability resulted from the improved hydrophilicity of the membrane surface, increased effective membrane surface area, and introduction of larger cavity at the interface between N-GOQD and PA matrix. In addition, favourable chemical bonding between polyamide and N-GOQD also greatly improved thermal stability of polyamide membrane, as indicated by thermal gravimetric analysis (TGA) measurements.

Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane exhibits chemical resistance for most agents used in membrane cleaning procedures, maintaining a stable flux and high salt rejection.

Pathogenetic justification of possibility of antidiuretic hormone use in incontinent women

Hypothesis/aims of study. Urine incontinence seems to include several pathogenetic forms, as efficient therapy is provided by different medications. Commonly used in the treatment of female patients with overactive bladder and nocturnal polyuria is desmopressin which normalizes the water excretion of the kidney, which is disturbed by a presumed inverted rhythm of vasopressin secretion in these patients. The current analysis was undertaken to evaluate the clinical efficiency of desmopressine in incontinent patients with nocturnal polyuria and polyuria.
 Study design, materials and methods. A total of 84 patients with complaints of urinary incontinence, polyuria (24-urine volume of 40 mL/kg bodyweight or above) or nocturnal polyuria (nocturnal volume/24-h urine volume of 0.33 or above) and 14 control subjects were included. Mean patient age was 43.6 ± 4.6 years, in control subjects 38.5 ± 6.4 (p > 0.05). All participants performed 24h-urinecollection to determine the voided volumes and the levels of creatinine, osmolality, sodium, magnesium and potassium for each sample. A blood sample was taken during the 24-urinecollection to determine the levels of creatinine, osmolality, sodium, magnesium and potassium. The examination of patients with polyuria and nocturnal polyuria was performed twice: in the initial state and one month after the start of treatment with optimal dose of desmopressin. Optimal dose was established through an open-label dose-titration using 0.1 mg, 0.2 mg and 0.4 mg of desmopressin (Minirin). Safety parameters assessed included incidence of adverse events, vital signs and serum sodium levels.
 Results. In patients with polyuria and nocturnal polyuria the glomerular filtration rate was normal, whereas diuresis and solute (sodium, magnesium, potassium) excretion in night samples in nocturnal polyuria and both in night and day samples in polyuria were increased. The higher diuresis and the higher solute excretion observed in nocturnal polyuria and polyuria are accompanied by an increase of free water reabsorption. In nocturnal polyuria and polyuria a high correlation was found between the free water reabsorption and solute excretion. This occurs against the background of the high night and day osmotic concentration. The statistically significant recovery of renal function occurred in 12 incontinent women with polyuria and 18 with nocturnal polyuria. In these papients there was a statistically significant decrease in diuresis, osmolar clearance and excretion of sodium, potassium and magnesium.
 Concluding message. As desmopressin affects cells of the thick ascending limb of Henle’s loop, it is likely that nocturnal polyuria and polyuria result from a disturbed regulation of the function of these cells. Normalization can be achieved by desmopressin administration to stimulate V2-receptors, which increase water permeability and water reabsoption in collecting ducts as well as ion reabsorption by cells of the thick ascending limb of Henle’s loop.

Enzymatic hydrolysis of poly(ethyleneterephthalate) used for and analysed by pore modification of track-etched membranes

The potential of limited enzymatic poly(ethylene terephthalate) (PET) surface hydrolysis for the modification of track-etched (TE) membranes was investigated. Cutinases 1 and 2 from Thermobifida cellulosilytica as well as a fusion protein of cutinase 1 with the polymer binding module from the polyhydroxyalkanoate depolymerase of Alcaligenes faecalis (Thc_Cut1_PBM) were shown to hydrolyse highly crystalline PET TE membranes with a pore diameter of ∼120nm at very narrow size distribution. Furthermore the effects of surface chemistry were investigated by comparison of enzymatic hydrolysis by Thc_Cut1_PBM of “as received” PET TE membranes with two surface functionalized versions towards a “hydrophilic” and a more “hydrophobic” surface. The effects of adsorbed protein and the efficacy of cleaning steps after enzymatic treatment were elucidated by complementary methods for surface analysis and membrane characterization. With the optimized cleaning protocol, all adsorbed protein could be removed from the enzyme-treated membranes and effects of chemical surface functionalization of the PET TE membranes were demonstrated. The highest efficiency of enzymatic surface hydrolysis was observed for the original PET TE membranes, leading to an 0.36% weight loss corresponding to a removal of ∼3nm PET from the entire surface of the porous membrane. This correlates very well with the measured increase of barrier pore diameter by 4nm (a radius reduction? of 2nm), leading to about a two-fold increased water permeability.

Effects of surface modification of silane coupling agent on the properties of concrete with freeze-thaw damage

Surface waterproofing treatment with silane coupling agent is developed to prepare surface modification concrete, in recent years, which possesses an excellent permeability resistance. Freeze-thaw damage inevitable exists in concrete exposed to the cold environment, therefor this paper intensively investigates the effects of surface modification of silane coupling agent on the properties of concrete with freeze-thaw damage. Freeze-thaw cycles, capillary absorption, chloride penetration and carbonization tests were carried out, respectively. The results demonstrate that the surface waterproofing treatment is appropriate for the durability repairing of concrete with freeze-thaw damage, and the penetration depth of silane coupling agent in concrete increases linearly with the rise of freeze-thaw damage. The water and chloride permeability both increase with the increased freeze-thaw cycles for various concrete; however, the surface modification concrete has a better permeability resistance than ordinary concrete with the same freeze-thaw damage. In particular, the permeability resistance increases with the increases of applied amount of silane coupling agent, and there exists a good correlation between the permeability behavior and induced freeze-thaw damage for various concrete. Abrasion significantly decrease the permeability resistance of surface modification concrete, which should be considered carefully in the durability repairing.

Preparation of Low fouling Polyethersulfone Membranes by Simultaneously Phase Separation and Redox Polymerization

This paper presents preparation of low fouling PES membranes by non solvent induced phase separation (NIPS) coupled with redox polymerization. The membrane characterization included water permeability, morphology structure (by SEM) and surface chemistry (by FTIR). Water permeability measurements showed thatthe membranes have water permeability within the range 10-50 L/h.m2.bar. Addition of PEG dan PEGMA intopolymer solution increased water permeability, whereas blending redox initiator and crosslinker, MBAA in polymer solution decreased water permeability. Surface morfology of membranes by SEM showed that unmodified PES membrane had smaller pore size than PEG or PEGMA modified PES membranes. Furthermore, PES-PEG or PES-PEGMA membranes modified by blending with redox initiator and MBAA as crosslinker showed smaller pore size than unmodified membrane. FTIR analysis showed that all membranes have typical spectraof PES polymer; however no additional peak was observed forthe membranes prepared with addition of PEG/PEGMA, initiator redox and also crosslinker. The addition of PEG/PEGMA, redox initiator and crosslinker resulted in membranes with high rejection and an acceptable flux as well as more stable due to relatively high fouling resistance.

Cysteamine- and graphene oxide-mediated copper nanoparticle decoration on reverse osmosis membrane for enhanced anti-microbial performance

In this work, copper nanoparticles (CuNPs) were decorated onto the polyamide RO membranes via in-situ reduction for biofouling mitigation. To increase CuNPs loading and improve anti-microbial properties of the membrane, cysteamine (Cys) and graphene oxide (GO), which contain different functional groups with high metal affinity, were applied as bridging agents between CuNPs and membrane surface via covalent bonding. The functionalization of Cys and GO linkers on membrane was confirmed by XPS and SEM analysis. By applying the linkers, the loading quantity of copper, in particular on Cys-modified membrane, was significantly improved and the particle size of CuNPs appeared smaller and had more uniform distribution. The GO medium increased the hydrophilicity of CuNP-decorated membranes, leading to an increase in water permeation with minor impact on membrane’s salt rejection. Bacterial inactivation of the Cys-Cu- and GO-Cu-functionalized membranes was over 25% higher than that of the bare CuNP-coated surface, indicating enhanced bacterial inactivation benefiting from the application of linkers. After a CuNPs’ release test, the membranes modified with Cys and GO retained larger quantities of CuNPs and showed better antimicrobial performance than that of bare CuNP-modified membranes. The successful regeneration of CuNPs after their depletion demonstrated the modified membranes’ potential for long-term application.

Acyl-chloride quenching following interfacial polymerization to modulate the water permeability, selectivity, and surface charge of desalination membranes

Fully aromatic polyamide thin-film composite (TFC) membranes are the industry standard for membrane-based desalination. Due to the extensive application of TFC membranes to treat feed waters of widely varying composition, new methods are needed to modulate the water permeability, water–solute selectivity, and surface charge of the polyamide selective layer. In this study, the quenching of residual acyl-chloride groups in nascent polyamide films is performed using amine, ammonia, and alcohol solutions, including common alcohol solvents such as methanol and ethanol. Membrane transport characterization in reverse osmosis demonstrates that quenching can substantially increase water permeability. For example, quenching in ammonium hydroxide resulted in water permeability of 2.50Lm−2h−1bar−1, which was 2.8 times greater than that for water-quenched control membranes, paired with a small decrease in sodium chloride rejection from 99.7% to 99.3%. By using different quenching solutions, quenching resulted in a range of water permeabilities (0.15–2.50Lm−2h−1bar−1) and water–salt selectivities (98.4–99.7% salt rejection), with performance falling along a previously proposed permeability–selectivity trade-off. Transport behavior and surface characterization indicate that chemical reactions occur to form amides and esters during quenching. Additionally, quenching decreased the carboxyl group density from 25.5 sites/nm2 for water-quenched control membranes to 11.8 sites/nm2 for membranes quenched in ammonium hydroxide. Taken together, the results demonstrate that acyl-chloride quenching provides a novel route to alter the surface charge in addition to water permeability and water–salt selectivity. Potential ways to further optimize the method are discussed.

Hypoxia augments LPS-induced inflammation and triggers high altitude cerebral edema in mice

High altitude cerebral edema (HACE) is a life-threatening illness that develops during the rapid ascent to high altitudes, but its underlying mechanisms remain unclear. Growing evidence has implicated inflammation in the susceptibility to and development of brain edema. In the present study, we investigated the inflammatory response and its roles in HACE in mice following high altitude hypoxic injury. We report that acute hypobaric hypoxia induced a slight inflammatory response or brain edema within 24h in mice. However, the lipopolysaccharide (LPS)-induced systemic inflammatory response rapidly aggravated brain edema upon acute hypobaric hypoxia exposure by disrupting blood-brain barrier integrity and activating microglia, increasing water permeability via the accumulation of aquaporin-4 (AQP4), and eventually leading to impaired cognitive and motor function. These findings demonstrate that hypoxia augments LPS-induced inflammation and induces the occurrence and development of cerebral edema in mice at high altitude. Here, we provide new information on the impact of systemic inflammation on the susceptibility to and outcomes of HACE.

Mechanical properties and durability of roller compacted concrete pavements in cold regions

Roller compacted concrete pavement is a cost effective and beneficial pavement system which needs fewer material and less energy than other kinds of pavements. An important problem with the pavements is salt scaling that occurs due to a saline solution on cementitious surfaces. In order to reduce the negative effects of salt scaling, the influence of cement replacement by trass, a natural pozzolan, has been investigated. Mechanical and durability tests and salt scaling with air void analysis on hardened concrete were carried out to evaluate the effect of ordinary/trass selected mixes with/without air entraining agents. Results generally showed that although usage of air entraining agents reduced compressive and tensile strengths and increased water permeability and capillary absorption, it performed well against salt scaling in freeze-thaw cycles. The control samples with less w/c performed better than trass samples. In this research, spacing factor obtained about 0.07mm and 0.1mm for air-entrained and non air-entrained samples respectively.

Modulation of Endothelial Membrane Biomechanics by Oxidized Phospholipids: A Combined Experimental and Computational Approach

Elevated concentrations of biologically active oxidized phospholipids (oxPCs) are known to exert various pathophysiological effects, including disruption of the endothelial barrier and induction of monocyte adhesion to endothelial cells. These effects are further implicated in a range of disorders, including certain cardiovascular, metabolic, and immunological diseases. The specific mechanisms by which oxPCs modulate membrane barrier function are poorly understood.We investigated the differential influence of two bioactive oxidized phospholipids on model bilayer properties, membrane packing, fluidity, elastic properties, and endothelial cell biomechanics both experimentally, using Laurdan multi‐photon imaging and atomic force microscopy (AFM) microindentation experiments, and computationally, using coarse‐grained molecular dynamics simulations. Specifically, we focused on two major oxidation products of 1‐palmitoyl‐2‐arachidonoyl‐sn‐glycero‐3‐phosphocholine (PAPC), which are known to exert multiple pathophysiological effects. The oxidized phospholipids 1‐palmitoyl‐2‐(5‐oxovaleroyl)‐sn‐glycero‐3‐phosphocholine (POVPC ‐ aldehyde‐terminated) and 1‐palmitoyl‐2‐glutaroyl‐sn‐glycero‐3‐phosphocholine (PGPC ‐ carboxyl‐terminated) have been found to induce inflammation, cell proliferation, and cell death.Our molecular simulations of multicomponent phospholipid bilayers predicted differential bilayer perturbation effects of the two oxidized phospholipids based on the chemical identities of their truncated tails. We showed that for the analogous oxPCs incorporated in a phosphatidylcholine bilayer containing sphingomyelin, the carboxylic analog, PGPC, experienced more significant reorientation of the truncated tail and displacement of the oxidized lipid from the plane of the bilayer. These phenomena induced greater perturbation of the structure of the lipid bilayer than the aldehyde analog, POVPC. Decreased bilayer packing and increased water permeation was observed, which was consistent with Laurdan imaging results. Spectral analysis of bilayer undulations further indicated increased elasticity of bilayer systems containing both oxPCs. Computational predictions of larger membrane perturbation by PGPC corresponded with greater stiffness observed for PGPC‐treated endothelial cells measured by cellular elastic moduli using AFM. These analyses confirmed the paradoxical relationship observed between membrane softening by oxPCs and increased overall cell stiffness in the presence of POVPC and PGPC.Support or Funding InformationNIH grants: T32 HL‐82547, HL‐073965, HL‐083298; AHA MWA Pre‐doctoral Fellowship: 14PRE20490156

Carbon-based building blocks for alcohol dehydration membranes with disorder-enhanced water permeability

Graphene oxide (GO) thin films have demonstrated outstanding water permeability and excellent selectivity towards organic molecules and inorganic salts, unlocking a new exciting direction in the development of nanofiltration, desalination and pervaporation membranes. However, there are still high concerns about their stability at basic pH and under cross-flow conditions. The stabilization of graphene oxide can be achieved by thermal or chemical reduction; but stacked layers of reduced GO tend to form ordered and compact graphite-like structures, thus preventing their application as molecular separation membranes. In this work, a humic acid-like biopolymer (HAL), extracted from organic compost with a yield of ∼20%, was used to fabricate composite GO-HAL membranes. The HAL brings a high degree of disorder to the membrane structure, with the benefit of an increased water permeation rate. Upon thermal stabilization, the membrane with a biopolymer loading of 30% presented an ideal water/ethanol selectivity of 45 and a water permeance that is 33% higher than the pristine graphene oxide membrane. The enhanced water permeability along with the good water/ethanol selectivity makes the GO-HAL membranes promising devices for alcohol dehydration technologies.

Yeast aquaporin regulation by 4-hydroxynonenal is implicated in oxidative stress response.

Reactive oxygen species, especially hydrogen peroxide (H2 O2 ), contribute to functional molecular impairment and cellular damage, but also are necessary in normal cellular metabolism, and in low doses play stimulatory role in cell proliferation and stress resistance. In parallel, reactive aldehydes such as 4-hydroxynonenal (HNE), are lipid peroxidation breakdown products which also contribute to regulation of numerous cellular processes. Recently, channeling of H2 O2 by some mammalian aquaporin isoforms has been reported and suggested to contribute to aquaporin involvement in cancer malignancies, although the mechanism by which these membrane water channels are implicated in oxidative stress is not clear. In this study, two yeast models with increased levels of membrane polyunsaturated fatty acids (PUFAs) and aquaporin AQY1 overexpression, respectively, were used to evaluate their interplay in cell's oxidative status. In particular, the aim of the study was to investigate if HNE accumulation could affect aquaporin function with an outcome in oxidative stress response. The data showed that induction of aquaporin expression by PUFAs results in increased water permeability in yeast membranes and that AQY1 activity is impaired by HNE. Moreover, AQY1 expression increases cellular sensitivity to oxidative stress by facilitating H2 O2 influx. On the other hand, AQY1 expression has no influence on the cellular antioxidant GSH levels and catalase activity. These results strongly suggest that aquaporins are important players in oxidative stress response and could contribute to regulation of cellular processes by regulation of H2 O2 influx. © 2017 IUBMB Life, 69(5):355-362, 2017.

Water Permeability Adjusts Resorption in Lung Epithelia to Increased Apical Surface Liquid Volumes.

The apical surface liquid (ASL) layer covers the airways and forms a first line of defense against pathogens. Maintenance of ASL volume by airway epithelia is essential for maintaining lung function. The proteolytic activation of epithelial Na+ channels is believed to be the dominating mechanism to cope with increases in ASL volumes. Alternative mechanisms, in particular increases in epithelial osmotic water permeability (Posm), have so far been regarded as rather less important. However, most studies mainly addressed immediate effects upon apical volume expansion (AVE) and increases in ASL. This study addresses the response of lung epithelia to long-term AVE. NCI-H441 cells and primary human tracheal epithelial cells, both cultivated in air-liquid interface conditions, were used as models for the lung epithelium. AVE was established by adding isotonic solution to the apical surface of differentiated lung epithelia, and time course of ASL volume restoration was assessed by the deuterium oxide dilution method. Concomitant ion transport was investigated in Ussing chambers. We identified a low resorptive state immediately after AVE, which coincided with proteolytic ion transport activation within 10-15 minutes after AVE. The main clearance of excess ASL occurred during a delayed (hours after AVE) high resorptive state, which did not correlate with ion transport activation. Instead, high resorptive state onset coincided with an increase in Posm, which depended on aquaporin up-regulation. In summary, our data demonstrate that, aside from ion transport activation, modulation of Posm is a major mechanism to compensate for long-term AVE in lung epithelia.

Polysulfone/Polyacrilonitrile Membrane for Oil/Water Separation

Polysulfone (PSF)/polyacrylonitrile (PAN) membrane had been developed by electrospinning method to investigate the ability of membrane for oil/water separation. The ratios of PSF to PAN were varied as 7:3, 5:5, 3:7, and 0:10 in 10wt% of total concentration. In general, ratio PSF to PAN 5:5 gave the best morphology with smooth nanofibers and good permeability. The results show that increase of PAN concentration leads to the increase of water permeability. The addition of PAN into PSF changed the membrane surface properties from hydrophobic to hydrophilic. PAN/PSF membrane with a ratio of PSF to PAN as 5:5, 3:7, and 0:10 were showing high resistant for oil. It suggested that PSF/PAN membrane with the large composition of PAN could be used as water/oil separator.