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Sample records for globule membrane mfgm

  1. Comparison of Milk Fat Globule Membrane (MFGM) Proteins of Chianina and Holstein Cattle Breed Milk Samples Through Proteomics Methods

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    Lorraine Pariset; Silvia Bongiorni; Alessio Valentini; Lello Zolla; Leonardo Murgiano; Anna Maria Timperio

    2009-01-01

    Identification of proteins involved in milk production is important to understand the biology of lactation. Many studies have advanced the understanding of mammary function and milk secretion, but the critical molecular mechanisms implicated in milk fat secretion is still incomplete. Milk Fat Globules are secreted from the apical surface of the mammary cells, surrounded by a thin membrane bilayer, the Milk Fat Globule Membrane (MFGM), formed by proteins which have been suggested to be cholest...

  2. Comparison of Milk Fat Globule Membrane (MFGM Proteins of Chianina and Holstein Cattle Breed Milk Samples Through Proteomics Methods

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    Lorraine Pariset

    2009-12-01

    Full Text Available Identification of proteins involved in milk production is important to understand the biology of lactation. Many studies have advanced the understanding of mammary function and milk secretion, but the critical molecular mechanisms implicated in milk fat secretion is still incomplete. Milk Fat Globules are secreted from the apical surface of the mammary cells, surrounded by a thin membrane bilayer, the Milk Fat Globule Membrane (MFGM, formed by proteins which have been suggested to be cholesterolemia-lowering factors, inhibitors of cancer cell growth, vitamin binders, bactericidal, suppressors of multiple sclerosis. Using a proteomic approach, we compared MFGM from milk samples of individuals belonging to two different cattle breeds, Chianina and Holstein, representative of selection for milk and meat traits, respectively. We were able to isolate some of the major MFGM proteins in the examined samples and to identify differences between the protein fractions of the two breeds. We detected differences in the amount of proteins linked to mammary gland development and lipid droplets formation, as well as host defence mechanisms. We have shown that proteomics is a suitable, unbiased method for the study of milk fractions proteins and a powerful tool in nutritional genomics.

  3. Quantitative proteomic analysis of milk fat globule membrane (MFGM) proteins in human and bovine colostrum and mature milk samples through iTRAQ labeling.

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    Yang, Mei; Cong, Min; Peng, Xiuming; Wu, Junrui; Wu, Rina; Liu, Biao; Ye, Wenhui; Yue, Xiqing

    2016-05-18

    Milk fat globule membrane (MFGM) proteins have many functions. To explore the different proteomics of human and bovine MFGM, MFGM proteins were separated from human and bovine colostrum and mature milk, and analyzed by the iTRAQ proteomic approach. A total of 411 proteins were recognized and quantified. Among these, 232 kinds of differentially expressed proteins were identified. These differentially expressed proteins were analyzed based on multivariate analysis, gene ontology (GO) annotation and KEGG pathway. Biological processes involved were response to stimulus, localization, establishment of localization, and the immune system process. Cellular components engaged were the extracellular space, extracellular region parts, cell fractions, and vesicles. Molecular functions touched upon were protein binding, nucleotide binding, and enzyme inhibitor activity. The KEGG pathway analysis showed several pathways, including regulation of the actin cytoskeleton, focal adhesion, neurotrophin signaling pathway, leukocyte transendothelial migration, tight junction, complement and coagulation cascades, vascular endothelial growth factor signaling pathway, and adherens junction. These results enhance our understanding of different proteomes of human and bovine MFGM across different lactation phases, which could provide important information and potential directions for the infant milk powder and functional food industries.

  4. Effects of exercise and milk fat globule membrane (MFGM supplementation on body composition, physical function, and hematological parameters in community-dwelling frail Japanese women: a randomized double blind, placebo-controlled, follow-up trial.

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    Hunkyung Kim

    Full Text Available To investigate the combined and separate effects of exercise and milk fat globule membrane (MFGM supplementation on frailty, physical function, physical activity level, and hematological parameters in community-dwelling elderly Japanese women.A total of 131 frail, elderly women over 75 years were randomly assigned to one of four groups: exercise and MFGM supplementation (Ex+MFGM, exercise and placebo (Ex+Plac, MFGM supplementation, or the placebo group. The exercise group attended a 60-minute training program twice a week for three months, and the MFGM group ingested 1g of the MFGM supplement in pill form, daily for 3 months. The primary outcome measure was change in frailty status based on Fried's frailty phenotype. Secondary outcome measures included body composition, physical function and hematological parameters, and interview survey components assessing lifestyle factors. Participants were followed for 4 months post-intervention.Significant group × time interactions were observed for usual walking speed (P = 0.005, timed up & go (P<0.001, and insulin-like growth factor-binding protein 3/insulin-like growth factor 1 ratio (P = 0.013. The frailty components revealed that weight loss, exhaustion, low physical activity, and slow walking speed were reversed, but low muscle strength did not significantly changed. Frailty reversal rate was significantly higher in the Ex+MFGM (57.6% than in the MFGM (28.1% or placebo (30.3% groups at post-intervention (χ2 = 8.827, P = 0.032, and at the follow-up was also significantly greater in the Ex+MFGM (45.5% and Ex+Plac (39.4% groups compared with the placebo (15.2% group (χ2 = 8.607, P = 0.035. The exercise+MFGM group had the highest odds ratio (OR for frailty reversal at post-intervention and follow-up (OR = 3.12, 95% confidence interval (CI = 1.13-8.60; and OR = 4.67, 95% CI = 1.45-15.08, respectively.This study suggests that interventions including exercise and nutrition can improve frailty status

  5. Milk fat globule membrane glycoproteins: Valuable ingredients for lactic acid bacteria encapsulation?

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    Guerin, Justine; Burgain, Jennifer; Gomand, Faustine; Scher, Joël; Gaiani, Claire

    2017-10-04

    The membrane (Milk Fat Globule Membrane - MFGM) surrounding the milk fat globule is becoming increasingly studied for its use in food applications due to proven nutritional and technological properties. This review focuses first on current researches which have been led on the MFGM structure and composition and also on laboratory and industrial purification and isolation methods developed in the last few years. The nutritional, health benefits and techno-functional properties of the MFGM are then discussed. Finally, new techno-functional opportunities of MFGM glycoproteins as a possible ingredient for Lactic Acid Bacteria (LAB) encapsulation are detailed. The ability of MFGM to form liposomes entrapping bioactive compounds has been already demonstrated. One drawback is that liposomes are too small to be used for bacteria encapsulation. For the first time, this review points out the numerous advantages to use MFGM glycoproteins as a protecting, encapsulating matrix for bacteria and especially for LAB.

  6. Major proteins of the goat milk fat globule membrane.

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    Cebo, C; Caillat, H; Bouvier, F; Martin, P

    2010-03-01

    Fat is present in milk as droplets of triglycerides surrounded by a complex membrane derived from the mammary epithelial cell called milk fat globule membrane (MFGM). Although numerous studies have been published on human or bovine MFGM proteins, to date few studies exist on MFGM proteins from goat milk. The objective of this study was thus to investigate the protein composition of the goat MFGM. Milk fat globule membrane proteins from goat milk were separated by 6% and 10% sodium dodecyl sulfate-PAGE and were Coomassie or periodic acid-Schiff stained. Most of MFGM proteins [mucin-1, fatty acid synthase, xanthine oxidase, butyrophilin, lactadherin (MFG EGF-8, MFG-E8), and adipophilin] already described in cow milk were identified in goat milk using peptide mass fingerprinting. In addition, lectin staining provided a preliminary characterization of carbohydrate structures occurring on MFGM proteins from goat milk depending on alpha(S1)-casein genotype and lactation stage. We provide here first evidence of the presence of O-glycans on fatty acid synthase and xanthine oxidase from goat milk. A prominent difference between the cow and the goat species was demonstrated for lactadherin. Indeed, whereas 2 polypeptide chains were easily identified by peptide mass fingerprinting matrix-assisted laser desorption/ionization-time of flight analysis within bovine MFGM proteins, lactadherin from goat milk consisted of a single polypeptide chain. Another striking observation was the presence of caseins associated with MFGM preparations from goat milk, whereas virtually no caseins were found in MFGM extracts from bovine milk. Taken together, these observations strongly support the existence of a singular secretion mode previously hypothesized in the goat.

  7. Proteomics of the milk fat globule membrane from Camelus dromedarius.

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    Saadaoui, Besma; Henry, Céline; Khorchani, Touhami; Mars, Mohamed; Martin, Patrice; Cebo, Christelle

    2013-04-01

    Camel milk has been widely characterized with regards to casein and whey proteins. However, in camelids, almost nothing is known about the milk fat globule membrane (MFGM), the membrane surrounding fat globules in milk. The purpose of this study was thus to identify MFGM proteins from Camelus dromedarius milk. Major MFGM proteins (namely, fatty acid synthase, xanthine oxidase, butyrophilin, lactadherin, and adipophilin) already evidenced in cow milk were identified in camel milk using MS. In addition, a 1D-LC-MS/MS approach led us to identify 322 functional groups of proteins associated with the camel MFGM. Dromedary MFGM proteins were then classified into functional categories using DAVID (the Database for Annotation, Visualization, and Integrated Discovery) bioinformatics resources. More than 50% of MFGM proteins from camel milk were found to be integral membrane proteins (mostly belonging to the plasma membrane), or proteins associated to the membrane. Enriched GO terms associated with MFGM proteins from camel milk were protein transport (p-value = 1.73 × 10(-14)), translation (p-value = 1.08 × 10(-11)), lipid biosynthetic process (p-value = 6.72 × 10(-10)), hexose metabolic process (p-value = 1.89 × 10(-04)), and actin cytoskeleton organization (p-value = 2.72 × 10(-04)). These findings will help to contribute to a better characterization of camel milk. Identified MFGM proteins from camel milk may also provide new insight into lipid droplet formation in the mammary epithelial cell. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Milk fat globule membrane and buttermilks: from composition to valorization

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    Vanderghem, C.

    2010-01-01

    Full Text Available Buttermilk, the by-product from butter manufacture, is low cost and available in large quantities but has been considered for many years as invaluable. However, over the last two decades it has gained considerable attention due to its specific composition in proteins and polar lipids from the milk fat globule membrane (MFGM. The aim of this review is to take stock of current buttermilk knowledge. Firstly, the milk fat globule membrane composition and structure are described. Secondly, buttermilk and its associated products are defined according to the milk fat making process. Structure and mean composition of these products are summarized from recent dairy research data and related to technological properties, especially the emulsifying properties provided by MFGM components. Finally, new applications are presented, leading to promising valorizations of buttermilk and its derivate products.

  9. Comparative proteomics of milk fat globule membrane in different species reveals variations in lactation and nutrition.

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    Lu, Jing; Wang, Xinyu; Zhang, Weiqing; Liu, Lu; Pang, Xiaoyang; Zhang, Shuwen; Lv, Jiaping

    2016-04-01

    In present study, 312, 554, 175 and 143 proteins were identified and quantified by label-free quantitative proteomics in human, cow, goat and yak milk fat globule membrane (MFGM), respectively. Fifty proteins involved in vesicle mediate transport and milk fat globule secretion were conserved among species. Moreover, proteins involved in lipid synthesis and secretion (xanthine dehydrogenase/oxidase, stomatin and CD36), showed different expression pattern and the host defense proteins exhibited various profiles within species. Notably, the content and activity of lipid catabolic enzymes were significantly higher in human MFGM, which could be indicative of the superior fat utilization in breast fed infants. Our findings unraveled the significant differences in protein composition of human milk and conventionally used substitutes of it. The in-depth study of lipid metabolic enzymes in human MFGM will probably contribute to the improvement of the fat utilization through modulation of lipid catabolic enzymes in infant formula. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Milk fat globule membrane isolate induces apoptosis in HT-29 human colon cancer cells.

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    Zanabria, Romina; Tellez, Angela M; Griffiths, Mansel; Corredig, Milena

    2013-02-01

    A native milk fat globule membrane (MFGM) isolate obtained from raw milk was assessed for its anticarcinogenic capacity using a colon cancer cell line (HT-29). To prevent microbial contamination and eliminate the presence of lipopolysaccharide (LPS) in the milk used for MFGM isolation, the milk was obtained from the mammary glands of cows using a catheter. Cell proliferation assays demonstrated a reduction of exponentially growing cancer cells of up to 53%, expressed as DNA synthesis (BrdU test), after 72 h stimulation with 100 μg of MFGM protein per mL. Using a similar MFGM concentration, the sulforhodamine B assay resulted in 57% reduction of cell density after 48 h incubation. This bioactivity was comparable to that of known anticancer drugs, 0.1 mM melphalan and 20 μM C2-ceramide, which achieved a cell division reduction of 25 and 40%, respectively, under the same experimental conditions. The toxic effect of the MFGM extracts on HT-29 cells was confirmed by the significant reduction in lactate dehydrogenase enzyme (LDH) by the residual viable cells. An increase of caspase-3 activity (up to 26%) led to the conclusion that MFGM has an apoptotic effect on HT-29 cancer cells.

  11. Phosphoproteomics of the goat milk fat globule membrane: New insights into lipid droplet secretion from the mammary epithelial cell.

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    Henry, Céline; Saadaoui, Besma; Bouvier, Frédéric; Cebo, Christelle

    2015-07-01

    Mechanisms of milk lipid secretion are highly controversial. Analyzing the fine protein composition of the "milk fat globule membrane" (MFGM), the triple-layered membrane surrounding milk lipid droplets (LDs) can provide mechanistic clues to better understand LD biosynthesis and secretion pathways in mammary epithelial cells (MECs). We therefore combined a high-sensitive Q-Exactive LC-MS/MS analysis of MFGM-derived peptides to the use of an in-house database intended to improve protein identification in the goat species. Using this approach, we performed the identification of 442 functional groups of proteins in the MFGM from goat milk. To get a more dynamic view of intracellular mechanisms driving LD dynamics in the MECs, we decided to investigate for the first time whether MFGM proteins were phosphorylated. MFGM proteins were sequentially digested by lysine-C and trypsin proteases and the resulting peptides were fractionated by a strong cation exchange chromatography. Titanium beads were used to enrich phosphopeptides from strong cation exchange chromatography eluted fractions. This approach lets us pinpoint 271 sites of phosphorylation on 124 unique goat MFGM proteins. Enriched GO terms associated with phosphorylated MFGM proteins were protein transport and actin cytoskeleton organization. Gained data are discussed with regard to lipid secretory mechanisms in the MECs. All MS data have been deposited in the ProteomeXchange with identifier PXD001039 (http://proteomecentral.proteomexchange.org/dataset/PXD001039). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Cholesterol strongly affects the organization of lipid monolayers studied as models of the milk fat globule membrane: Condensing effect and change in the lipid domain morphology.

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    Murthy, Appala Venkata Ramana; Guyomarc'h, Fanny; Paboeuf, Gilles; Vié, Véronique; Lopez, Christelle

    2015-10-01

    The biological membrane that surrounds the milk fat globules exhibits phase separation of polar lipids that is poorly known. The objective of this study was to investigate the role played by cholesterol in the organization of monolayers prepared as models of the milk fat globule membrane (MFGM). Differential scanning calorimetry and X-ray diffraction experiments allowed characterization of the gel to liquid crystalline phase transition temperature of lipids, Tm ~35°C, in vesicles prepared with a MFGM lipid extract. For temperature below Tm, atomic force microscopy revealed phase separation of lipids at 30 mN·m(-1) in Langmuir-Blodgett monolayers of the MFGM lipid extract. The high Tm lipids form liquid condensed (LC) domains that protrude by about 1.5 nm from the continuous liquid expanded (LE) phase. Cholesterol was added to the MFGM extract up to 30% of polar lipids (cholesterol/milk sphingomyelin (MSM) molar ratio of 50/50). Compression isotherms evidenced the condensing effect of the cholesterol onto the MFGM lipid monolayers. Topography of the monolayers showed a decrease in the area of the LC domains and in the height difference H between the LC domains and the continuous LE phase, as the cholesterol content increased in the MFGM lipid monolayers. These results were interpreted in terms of nucleation effects of cholesterol and decrease of the line tension between LC domains and LE phase in the MFGM lipid monolayers. This study revealed the major structural role of cholesterol in the MFGM that could be involved in biological functions of this interface (e.g. mechanisms of milk fat globule digestion). Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Solubilization and purification of xanthine oxidase from bovine milk fat globule membrane.

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    Spitsberg, V L; Gorewit, R C

    1998-07-01

    Bovine milk xanthine oxidase (XO) was isolated and purified from milk fat globule membrane (MFGM). The method included the following steps: solubilization of XO from MFGM in 200 mM dithiothreitol (DTT) at pH 8.0, fractionation of solubilized proteins with ammonium sulfate, chromatography on DEAE-Sepharose with gradient elution, and rechromatography of the XO fraction for final purification. The method is highly reproducible, is comparatively simple, and provides highly pure enzyme. Purified XO, analyzed by (8%) SDS-PAGE, had only one band of 140-150 kDa. XO showed a high specific activity of 2.5 units/mg of protein and an A280: A450 ratio of 4.8. Copyright 1998 Academic Press.

  14. Dietary milk fat globule membrane supplementation combined with regular exercise improves skeletal muscle strength in healthy adults: a randomized double-blind, placebo-controlled, crossover trial.

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    Soga, Satoko; Ota, Noriyasu; Shimotoyodome, Akira

    2015-08-25

    Our previous studies demonstrated that dietary supplementation with milk fat globule membrane (MFGM) combined with habitual exercise improved muscle strength by stimulating neuromuscular development in mice. This study aimed to demonstrate the beneficial effects of dietary MFGM supplementation plus regular exercise on muscle strength and neuromuscular function in healthy humans. The study was designed as a randomized, double-blind, placebo-controlled, crossover trial. Fourteen Japanese adults aged 31-48 years took daily MFGM (1 g) or placebo tablets during the 4-week study period and attended a training program twice a week. Physical function tests and surface electromyography (EMG) were conducted at baseline and at the end of the study period. The MFGM group had significantly greater leg extension strength than the placebo group after the 4-week study period. Surface EMG showed that the MFGM group had a significantly higher root mean square amplitude than the placebo group, which indicated that the MFGM group had higher motor unit activity. Dietary MFGM supplementation combined with regular exercise improves skeletal muscle strength, which may be due to increased motor unit recruitment in healthy Japanese middle-aged adults.

  15. N-glycosylation proteomic characterization and cross-species comparison of milk fat globule membrane proteins from mammals.

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    Yang, Yongxin; Zheng, Nan; Wang, Weiyu; Zhao, Xiaowei; Zhang, Yangdong; Han, Rongwei; Ma, Lu; Zhao, Shengguo; Li, Songli; Guo, Tongjun; Zang, Changjiang; Wang, Jiaqi

    2016-11-01

    Glycosylation of proteins has been implicated in various biological functions and has received much attention; however, glycoprotein components and inter-species complexity have not yet been elucidated fully in milk proteins. N-linked glycosylation sites and glycoproteins in milk fat globule membrane (MFGM) fractions were investigated by combining N-glycosylated peptides enrichment and high-accuracy Q Exactive identification, to map the N-glycoproteome profiles in Holstein and Jersey cows, buffaloes, yaks, goats, camels, horses, and humans. A total of 399 N-glycoproteins with 677 glycosylation sites were identified in the MFGM fractions of the studied mammals. Most glycosylation sites in humans were classified as known and those in the other studied mammals as unknown, according to Swiss-Prot annotations. Functionally, most of the identified glycoproteins were associated with the 'response to stimulus' GO category. N-glycosylated protein components of MFGM fractions from Holstein and Jersey cows, buffaloes, yaks, and goats were more similar to each other compared with those of camels, horses and human. The findings increased the number of known N-glycosylation sites in the milk from dairy animal species, revealed the complexity of the MFGM glycoproteome, and provided useful information to further explore the mechanism of MFGM glycoproteins biosynthesis among the studied mammals. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Pulsed electric field processing preserves the antiproliferative activity of the milk fat globule membrane on colon carcinoma cells.

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    Xu, S; Walkling-Ribeiro, M; Griffiths, M W; Corredig, M

    2015-05-01

    The present work evaluated the effect of processing on the antiproliferative activities of milk fat globule membrane (MFGM) extracts. The antiproliferative activity on human adenocarcinoma HT-29 cells of untreated MFGM extracts were compared with those extracted from pasteurized cream, thermally treated cream, or cream subjected to pulsed electrical field (PEF) processing. The PEF with a 37 kV/cm field strength applied for 1,705μs at 50 and 65°C was applied to untreated cream collected from a local dairy. Heating at 50 or 65°C for 3min (the passage time in the PEF chamber) was also tested to evaluate the heating effect during PEF treatments. The MFGM extracted from pasteurized cream did not show an antiproliferative activity. On the other hand, isolates from PEF-treated cream showed activity similar to that of untreated samples. It was also shown that PEF induced interactions between β-lactoglobulin and MFGM proteins at 65°C, whereas the phospholipid composition remained unaltered. This work demonstrates the potential of PEF not only a means to produce a microbiologically safe product, but also as a process preserving the biofunctionality of the MFGM. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  17. Short communication: Annatto in Cheddar cheese-derived whey protein concentrate is primarily associated with milk fat globule membrane.

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    Zhu, D; Damodaran, S

    2012-02-01

    The yellow color of Cheddar cheese whey arises from a residual amount of annatto that partitions into the whey during Cheddar cheese manufacture. Bleaching of the color using hydrogen peroxide or benzoyl peroxide is often a prerequisite to produce an acceptable neutral-colored whey protein concentrate and isolate. However, the use of these strong oxidizing agents often generates off-flavors as a result of lipid oxidation and results in loss of nutritive value due to protein oxidation. The objective of this study was to determine the extent of partitioning of annatto between protein, milk fat globule membrane (MFGM), and aqueous (serum) phases of cheese whey so that a simple method can be developed to remove annatto from cheese whey. The MFGM was separated from Cheddar cheese whey using a recently developed novel method. Quantitative analysis of the distribution of annatto in the fat-free whey protein isolate (WPI), the MFGM fractions, and the serum phase revealed that annatto was not bound to the protein fraction but was mostly distributed between the serum phase and the MFGM fraction. The results showed that a colorless WPI or whey protein concentrate could be produced from Cheddar cheese whey by separation of MFGM from the whey, followed by diafiltration. This approach will negate the need for using bleaching agents. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  18. Evaluation of six sample preparation procedures for qualitative and quantitative proteomics analysis of milk fat globule membrane.

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    Yang, Yongxin; Anderson, Elizabeth; Zhang, Sheng

    2018-04-12

    Proteomic analysis of membrane proteins is challenged by the proteins solubility and detergent incompatibility with MS analysis. No single perfect protocol can be used to comprehensively characterize the proteome of membrane fraction. Here, we used cow milk fat globule membrane (MFGM) proteome analysis to assess six sample preparation procedures including one in-gel and five in-solution digestion approaches prior to LC-MS/MS analysis. The largest number of MFGM proteins were identified by suspension trapping (S-Trap) and filter-aided sample preparation (FASP) methods, followed by acetone precipitation without clean-up of tryptic peptides method. Protein identifications with highest average coverage was achieved by Chloroform/MeOH, in-gel and S-Trap methods. Most distinct proteins were identified by FASP method, followed by S-Trap. Analyses by Venn diagram, principal-component analysis, hierarchical clustering and the abundance ranking of quantitative proteins highlight differences in the MFGM fraction by the all sample preparation procedures. These results reveal the biased proteins/peptides loss occurred in each protocol. In this study, we found several novel proteins that were not observed previously by in-depth proteomics characterization of MFGM fraction in milk. Thus, a combination of multiple procedures with orthologous properties of sample preparation was demonstrated to improve the protein sequence coverage and expression level accuracy of membrane samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Yak milk fat globules from the Qinghai-Tibetan Plateau: Membrane lipid composition and morphological properties.

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    Luo, Jie; Huang, Ziyu; Liu, Hongna; Zhang, Yan; Ren, Fazheng

    2018-04-15

    Yak milk fat products constitute the base of Qinghai-Tibetan pastoralists' daily food intake. Despite the great importance of fat in processing and pastoralists' health, studies about yak milk fat are scarce. In this study, the lipid composition and the morphological properties of milk fat globule membranes (MFGMs) of yak milk were investigated. The results demonstrated that the yak milk had a higher cholesterol and sphingomyelin content compared to cow milk. In situ structural investigations performed at 25 °C by confocal microscopy showed the presence of lipid domains in yak MFGM, with a larger number and wider size range compared to cow milk. Moreover, the simultaneous localization of glycosylated molecules and polar lipids indicated that glycosylated molecules could be integrated into the lipid domains in yak MFGM. Different characteristics in yak MFGM could be related to the lipid composition and may affect the functions of yak milk lipids during processing and digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Comparative proteomics of milk fat globule membrane proteins from transgenic cloned cattle.

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    Shunchao Sui

    Full Text Available The use of transgenic livestock is providing new methods for obtaining pharmaceutically useful proteins. However, the protein expression profiles of the transgenic animals, including expression of milk fat globule membrane (MFGM proteins, have not been well characterized. In this study, we compared the MFGM protein expression profile of the colostrum and mature milk from three lines of transgenic cloned (TC cattle, i.e., expressing recombinant human α-lactalbumin (TC-LA, lactoferrin (TC-LF or lysozyme (TC-LZ in the mammary gland, with those from cloned non-transgenic (C and conventionally bred normal animals (N. We identified 1, 225 proteins in milk MFGM, 166 of which were specifically expressed only in the TC-LA group, 265 only in the TC-LF group, and 184 only in the TC-LZ group. There were 43 proteins expressed only in the transgenic cloned animals, but the concentrations of these proteins were below the detection limit of silver staining. Functional analysis also showed that the 43 proteins had no obvious influence on the bovine mammary gland. Quantitative comparison revealed that MFGM proteins were up- or down-regulated more than twofold in the TC and C groups compared to N group: 126 in colostrum and 77 in mature milk of the TC-LA group; 157 in colostrum and 222 in mature milk of the TC-LF group; 49 in colostrum and 98 in mature milk of the TC-LZ group; 98 in colostrum and 132 in mature milk in the C group. These up- and down-regulated proteins in the transgenic animals were not associated with a particular biological function or pathway, which appears that expression of certain exogenous proteins has no general deleterious effects on the cattle mammary gland.

  1. Comparative Proteomics of Milk Fat Globule Membrane Proteins from Transgenic Cloned Cattle

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    Wang, Jianwu; Zhang, Ran; Guo, Chengdong; Yu, Tian; Li, Ning

    2014-01-01

    The use of transgenic livestock is providing new methods for obtaining pharmaceutically useful proteins. However, the protein expression profiles of the transgenic animals, including expression of milk fat globule membrane (MFGM) proteins, have not been well characterized. In this study, we compared the MFGM protein expression profile of the colostrum and mature milk from three lines of transgenic cloned (TC) cattle, i.e., expressing recombinant human α-lactalbumin (TC-LA), lactoferrin (TC-LF) or lysozyme (TC-LZ) in the mammary gland, with those from cloned non-transgenic (C) and conventionally bred normal animals (N). We identified 1, 225 proteins in milk MFGM, 166 of which were specifically expressed only in the TC-LA group, 265 only in the TC-LF group, and 184 only in the TC-LZ group. There were 43 proteins expressed only in the transgenic cloned animals, but the concentrations of these proteins were below the detection limit of silver staining. Functional analysis also showed that the 43 proteins had no obvious influence on the bovine mammary gland. Quantitative comparison revealed that MFGM proteins were up- or down-regulated more than twofold in the TC and C groups compared to N group: 126 in colostrum and 77 in mature milk of the TC-LA group; 157 in colostrum and 222 in mature milk of the TC-LF group; 49 in colostrum and 98 in mature milk of the TC-LZ group; 98 in colostrum and 132 in mature milk in the C group. These up- and down-regulated proteins in the transgenic animals were not associated with a particular biological function or pathway, which appears that expression of certain exogenous proteins has no general deleterious effects on the cattle mammary gland. PMID:25133402

  2. Dietary prebiotics, milk fat globule membrane and lactoferrin affects structural neurodevelopment in the young piglet

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    Austin T Mudd

    2016-02-01

    Full Text Available Introduction: Milk fat globule membrane (MFGM and lactoferrin have been identified as two components that have potential to affect neurodevelopment. While concentrations of some MFGM constituents in infant formulas are within human milk range, they may not be present at optimal or clinically effective levels. However, lactoferrin levels of infant formulas are consistently reported to be lower than human milk. This study sought to provide a novel combination of prebiotics, bovine-derived milk fat globule membrane and lactoferrin and assess their influence on neurodevelopment. Methods: Twenty-four male piglets were provided either TEST (n=12 or CONT (n=12 diet from 2 to 31 d of age. Piglets underwent spatial T-maze assessment starting at 17 d of age, were subjected to magnetic resonance imaging at 30 d of age, and were euthanized for tissue collection at 31 d of age. Results: Diffusion tensor imaging revealed differences in radial (P = 0.032 and mean (P = 0.028 diffusivities in the internal capsule, where CONT piglets had higher rates of diffusion compared with TEST piglets. Voxel-based morphometry indicated larger (P < 0.05 differences in cortical grey and white matter concentrations, with CONT piglets having larger tissue clusters in these regions compared with TEST piglets. In the spatial T-maze assessment, CONT piglets exhibited shorter latency to choice compared with TEST piglets on d 2 of acquisition and d 3 and 4 of reversal. Conclusion: Observed differences in microstructure maturation of the internal capsule and cortical tissue concentrations suggest that piglets provided TEST diet were more advanced developmentally than piglets provided CONT diet. Therefore, supplementation of infant formula with prebiotics, milk fat globule membrane and lactoferrin may support neurodevelopment in human infants.

  3. Light rhythmic exercise with dietary milk fat globule membrane improves physical fitness in an elderly Japanese population: a double-blind randomized placebo-controlled trial.

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    Yoshinaka, Yasuko; Soga, Satoko; Ota, Noriyasu; Yokoyama, Keiichi; Yamada, Yosuke; Kimura, Misaka

    2018-01-03

    This study aimed to investigate the efficacy of home-based, light gymnastic exercise plus dietary milk fat globule membrane (MFGM) intake on physical fitness of an elderly Japanese sample in a pilot, double-blind, randomized, placebo-controlled trial. Seventy-one subjects (male, n = 13; female, n = 58) were randomly assigned into two groups: placebo (n = 35 [male, n = 6; female, n = 29]) and MFGM group (n = 36 [male, n = 7; female, n = 29]). The intervention was eight weeks. Subjects ingested either MFGM (1 g/day) or placebo tablets daily and engaged in an exercise program daily. Physical function tests were performed at baseline and after four and eight weeks. Foot tapping and open-close stepping scores significantly increased from baseline to eight weeks in the MFGM group. Study results suggest daily MFGM ingestion might further enhance the effects of light-intensity exercise in healthy elderly people.

  4. Proteomic characterization and comparison of mammalian milk fat globule proteomes by iTRAQ analysis.

    Science.gov (United States)

    Yang, Yongxin; Zheng, Nan; Zhao, Xiaowei; Zhang, Yangdong; Han, Rongwei; Ma, Lu; Zhao, Shengguo; Li, Songli; Guo, Tongjun; Wang, Jiaqi

    2015-02-26

    Milk fat globule membrane (MFGM) proteins are known to be involved in many biological functions; however, their components and inter-species complexity have not yet been completely elucidated. We investigated the protein composition of the MFGM-enriched fraction from Holstein, Jersey, yak, buffalo, goat, camel, horse, and human. Extracted proteins from the MFGM-enriched fractions were identified and quantified by an iTRAQ proteomic approach. We identified 520 protein species categorized as biological processes, cellular components and molecular function according to their annotation. Cellular process, localization, transport, signal transduction, and response to stimulus were the most common biological processes; binding and catalytic activities were the most prevalent molecular functions. Pathway analysis revealed several pathways, including glycolysis/gluconeogenesis, peroxisome proliferator-activated receptor signaling, and fatty acid biosynthesis. Quantified MFGM-enriched proteins were subjected to discriminative proteomic profiling by principal component analysis and a hierarchical clustering method, and then organized into four major clusters: (1) Holstein, Jersey, and yak milk; (2) buffalo and goat milk; (3) Holstein, Jersey, buffalo, yak, and goat milk; and (4) camel, horse, and human milk. These novel quantitative data provide insight into the protein composition of the MFGM and their potential physiological functions, and highlight the significant differences in the MFGM fractions among mammalian species. Milk fat globule membrane (MFGM) proteins have exhibited a relatively larger diversity than other milk fractions, and implicated health beneficial effects. Proteomic analysis of MFGM protein was mainly focused on human, bovine and goat in previous studies. Recently, there is an increasing demand for natural milk from minor dairy animals. Differences in protein components were not yet elucidated that required the integration of this information across

  5. [The interrelation between the secretory function of the bovine udder and the amount of prolactin receptors on the membranes of the milk fat globules during lactogenesis].

    Science.gov (United States)

    Larina, M M; Tumanova, E B; Popova, A A

    1995-07-01

    The prolactin receptors number reaches its maximal level in proestrus. The data obtained suggest a correlation between high-affinity prolactin receptors concentration on the milk fat globule membranes during proestrus and the cow milk yield. The membranes may provide a model for assessing the functional state and secretory activity of the cow mammary gland.

  6. Data from proteomic characterization and comparison of mammalian milk fat globule proteomes by iTRAQ analysis

    Directory of Open Access Journals (Sweden)

    Yongxin Yang

    2015-06-01

    Full Text Available Milk fat globules memebrane (MFGM-enriched proteomes from Holstein, Jersey, yak, buffalo, goat, camel, horse, and human were extracted and identified by an iTRAQ quantification proteomic approach. Proteomes data were analyzed by bioinformatic and multivariate statistical analysis and used to present the characteristic traits of the MFGM proteins among the studied mammals. The data of this study are also related to the research article “Proteomic characterization and comparison of mammalian milk fat globule proteomes by iTRAQ analysis” in the Journal of Proteomics [1].

  7. Butter making from caprine creams: effect of washing treatment on phospholipids and milk fat globule membrane proteins distribution.

    Science.gov (United States)

    Lamothe, Sophie; Robitaille, Gilles; St-Gelais, Daniel; Britten, Michel

    2008-11-01

    A washing treatment was applied to caprine cream before churning in order to improve phospholipids and MFGM protein purification from buttermilk and butter serum. Cream obtained from a first separation was diluted with water and separated a second time using pilot plant equipment. Regular and washed creams were churned to produce buttermilk and butter, from which butter serum was extracted. The washing treatment allowed a significant decrease of the casein content. As a result, the phospholipids-to-protein ratios in washed buttermilk and butter serum were markedly increased by 2.1 and 1.7-folds respectively, which represents an advantage for the production of phospholipids concentrates. However, when compared with bovine cream, lower phospholipids-to-protein ratios were observed when the washing treatment was applied to caprine cream. A higher concentration of MFGM protein and a lower retention of phospholipids during washing treatment are responsible for the lower phospholipids-to-protein ratios in buttermilk and butter serum obtained from caprine cream. The phospholipids distribution in the butter making process was similar to the one obtained from bovine regular and washed cream. Phospholipids were preferentially concentrated in the butter serum rather than the buttermilk fraction. This simple approach permitted the production of caprine and bovine butter sera extracts containing up to 180 and 240 g phospholipids/kg sera, respectively, on a dry basis.

  8. A major prolactin-binding complex on human milk fat globule membranes contains cyclophilins A and B: the complex is not the prolactin receptor.

    Science.gov (United States)

    Lorenson, Mary Y; Ueda, Eric K; Chen, KuanHui E; Walker, Ameae M

    2012-03-01

    Prolactin (PRL) in milk influences maturation of gastrointestinal epithelium and development of both the hypothalamo-pituitary and immune systems of offspring. Here, we demonstrate that most PRL in human milk is part of a novel, high-affinity, multicomponent binding complex found on the milk fat globule membrane and not in whey. To examine properties of the complex, a sensitive ELISA was developed such that human PRL (hPRL) binding to the complex was measured by loss of hPRL detectability; thus, as much as 50 ng of hPRL was undetectable in the presence of 10 μl of human milk. Using the same methodology, no comparable complex formation was observed with human serum or amniotic fluid. hPRL complexation in milk was rapid, time dependent, and cooperative. Antibodies to or competitors of the hPRL receptor (placental lactogen and growth hormone) showed the hPRL receptor was not involved in the complex. However, hPRL complexation was antagonized by cyclosporine A and anti-cyclophilins. The complex was very stable, resisting dissociation in SDS, urea, and dithiothreitol. Western analysis revealed an ∼75-kDa complex that included hPRL, cyclophilins A and B, and a 16-kDa cyclophilin A. Compared with noncomplexed hPRL, complexed hPRL in whole milk showed similar activation of STAT5 but markedly delayed activation of ERK. Alteration of signaling suggests that complex formation may alter hPRL biological activity. This is the first report of a unique, multicomponent, high-capacity milk fat reservoir of hPRL; all other analyses of milk PRL have utilized defatted milk.

  9. Proteome profile and biological activity of caprine, bovine and human milk fat globules.

    Science.gov (United States)

    Spertino, Stefano; Cipriani, Valentina; De Angelis, Chiara; Giuffrida, Maria Gabriella; Marsano, Francesco; Cavaletto, Maria

    2012-04-01

    Upon combining bidimensional electrophoresis with monodimensional separation, a more comprehensive analysis of the milk fat globule membrane has been obtained. The proteomic profile of caprine milk fat globules revealed the presence of butyrophilin, lactadherin and perilipin as the major proteins, they were also associated to bovine and human milk fat globule membranes. Xanthine dehydrogenase/oxidase has been detected only in monodimensional gels. Biological activity of milk fat globules has been evaluated in Caco2-cells, as a representative model of the intestinal barrier. The increase of cell viability was indicative of a potential nutraceutical role for the whole milk fat globule, suggesting a possible employment in milk formula preparation.

  10. Bovine milk proteome: Quantitative changes in normal milk exosomes, milk fat globule membranes and whey proteomes resulting from Staphylococcus aureus mastitis

    Science.gov (United States)

    Knowledge of milk protein composition/expression in healthy cows and cows with mastitis will provide information important for the dairy food industry, mammary biology and immune function in the mammary gland. To facilitate maximum protein discovery, milk was fractioned into whey, milk fat globule ...

  11. Microwave spectral lines in galactic dust globules

    International Nuclear Information System (INIS)

    Martin, R.N.; Barrett, A.H.

    1978-01-01

    In order to better understand galactic dust globules, a program of mapping several molecular transitions in these clouds has been undertaken. The results of observations of the J=1→0 rotational transitions of CO, 13 CO, C 18 O, and CS, the J=2→1rotational transitions of CS and C 34 S, the J, K=1, 1 and J, K=2, 2 inversion transitions of NH 3 , the J/sub KKprime/=1 11 →1 10 and J/sub KKprime/=2 12 →2 11 transitions of H 2 CO, and the OH 2 Pi/sub 3/2/F=2→2 and F=1→1 transitions are reported here. Twelve globules have been selected for observation; seven of these were studied in detail and the remainder observed only sparsely. A strong positive correlation appears to exist between the spatial extent of the molecular emission (or absorption) and the optical features of the globule. Even the main isotope of CO shows this correlation between dust extinction and molecular emission. Close examination of the Palomar prints reveals dust wherever CO is observed, and CO is probably a good tracer of dust extinction.The simultaneous observation of many molecular transitions has proven useful in obtaining reliable physical parameters for the dust globules. For example, CO and NH 3 are reliable thermometers of the kinetic temperature, and CS and NH 3 are indicators of the total gas density. The kinetic temperatures of the globules are almost always approx.10 K, and the derived H 2 densities are 10/sup 3.4/-10/sup 4.5/ cm -3 . The density in the core of the globules could well be larger than these value, which represent an average for the entire cloud. The kinetic temperature appears uniform across each cloud (within a few kelvins), in agreement with theoretical predictions. All of the globules studied in detail appear to be gravitationally bound and collapsing objects. Rotation has been observed in at least two globules (B163 and B163 SW). The projected axis of rotation is in a direction opposite to that of the Galaxy

  12. Dark Globule in IC 1396 (IRAC)

    Science.gov (United States)

    2003-01-01

    [figure removed for brevity, see original site] Click on image for larger view of inset NASA's Spitzer Space Telescope image of a glowing stellar nursery provides a spectacular contrast to the opaque cloud seen in visible light (inset). The Elephant's Trunk Nebula is an elongated dark globule within the emission nebula IC 1396 in the constellation of Cepheus. Located at a distance of 2,450 light-years, the globule is a condensation of dense gas that is barely surviving the strong ionizing radiation from a nearby massive star. The globule is being compressed by the surrounding ionized gas. The dark globule is seen in silhouette at visible-light wavelengths, backlit by the illumination of a bright star located to the left of the field of view.The Spitzer Space Telescope pierces through the obscuration to reveal the birth of new protostars, or embryonic stars, and previously unseen young stars. The infrared image was obtained by Spitzer's infrared array camera. The image is a four-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8.0 microns (red). The filamentary appearance of the globule results from the sculpting effects of competing physical processes. The winds from a massive star, located to the left of the image, produce a dense circular rim comprising the 'head' of the globule and a swept-back tail of gas.A pair of young stars (LkHa 349 and LkHa 349c) that formed from the dense gas has cleared a spherical cavity within the globule head. While one of these stars is significantly fainter than the other in the visible-light image, they are of comparable brightness in the infrared Spitzer image. This implies the presence of a thick and dusty disc around LkHa 349c. Such circumstellar discs are the precursors of planetary systems. They are much thicker in the early stages of stellar formation when the placental planet-forming material (gas and dust) is still present.

  13. Mature ovarian teratoma with large floating fat globules

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hye Min; Kim, See Hyung; Hwang, Il Seon [Keimyung University School of Medicine, Dongsan Medical Center, Daegu (Korea, Republic of)

    2016-04-15

    Mature ovarian teratoma (dermoid cyst), a germ cell neoplasm, is one of the most common ovarian tumors. It is composed of derivatives of three germ cell layers. A mature ovarian teratoma with intracystic fat globules is rare. The pathogenesis on the formation of fat globules is unclear. Here we present a pathologically proven cystic ovarian teratoma with three large floating fat globules in a young woman with CT and MR findings.

  14. Sugar-induced molten-globule model.

    Science.gov (United States)

    Davis-Searles, P R; Morar, A S; Saunders, A J; Erie, D A; Pielak, G J

    1998-12-01

    Proteins denature at low pH because of intramolecular electrostatic repulsions. The addition of salt partially overcomes this repulsion for some proteins, yielding a collapsed conformation called the A-state. A-states have characteristics expected for the molten globule, a notional kinetic protein folding intermediate. Here we show that the addition of neutral sugars to solutions of acid-denatured equine ferricytochrome c induces formation of the A-state in the absence of added salt. We characterized the structure and stability of the sugar-induced A-state with circular dichroism spectropolarimetry (CD) and NMR-monitored hydrogen-deuterium exchange experiments. We also examined the stability of the sugar-induced A-state as a function of sugar size and concentration. The results are interpreted using several models and we conclude that the stabilizing effect is consistent with increased steric repulsion between the protein and the sugar solutions.

  15. Fractal Globule as a model of DNA folding in eukaryotes

    Science.gov (United States)

    Imakaev, Maksim; Mirny, Leonid

    2012-02-01

    A recent study (Lieberman-Aiden et al., Science, 2009) observed that the structure of the genome, on the scale of a few megabases, is consistent with a fractal globule. The fractal globule is a quasi-equilibrium state of a polymer after a rapid collapse. First proposed theoretically in 1988, this structure had never been simulated. Fractal globule was seen as a state, in which each subchain is compact, and doesn't mix with other subchains due to their mutual unentanglement (topological constraints). We use GPU-assisted dynamics to create fractal globules of different sizes and observe their dynamics. Our simulations confirm that a polymer after rapid collapse has compact subchains. We measure the scaling of looping probability of a subchain with it's length, and observe the remarkably robust inverse proportionality. Dynamic simulation of the equilibration of this state show that it exhibits Rose type subdiffusion. Due to diffusion, fractal globule quickly degrades to a quasi-equilibrium state, in which subchains of a polymer are mixed, but topologically unentangled. We propose that separation of spatial and topological equilibration of a polymer chain might have implications in different fields of physics.

  16. [Globule size and the activation energy of an enzymatic process].

    Science.gov (United States)

    Krishtalik, L I

    1979-01-01

    The charge transfer reactions demand the polar medium reorganization the main part in the process energy being contributed by solvent reorganization. Protein globule excludes a part of the solvent from the interaction with the charge being transfered. Thus a strong decrease of the reorganization energy and hence of the activation energy is achieved (the gain of some kcal/mole). The effect rises at first rapidly with the globule radius but it becomes practically constant after some optimal radius is reached. The estimation of the optimal radius gives values of the order of magnitude of the enzymes molecule sizes.

  17. Subnuclear globules in simple mucinous glands of the gastrointestinal tract

    DEFF Research Database (Denmark)

    Holck, Susanne; Ingeholm, P.

    2007-01-01

    Pyloric and duodenal Brunner glands may be the site of a peculiar cytoplasmic change characterized by clear vacuoles or glassy eosinophilic globules, occupying a subnuclear position with displacement of the nuclei towards the lumenal surface. To our knowledge this previously documented,5,6 although...

  18. Effect of some stabilizing agents on globule characteristics and ...

    African Journals Online (AJOL)

    This study investigated the effects of some stabilizing agents (cassava, maize and bentonite mucilages) on globule characteristics and rheological properties of oil in water emulsions. Emulsions were prepared by mixing varying proportions of the mucilages with Arachis oil in the ratio of 60:40 (oil: water) with the aid of a ...

  19. Rosette nebula globules: Seahorse giving birth to a star

    Science.gov (United States)

    Mäkelä, M. M.; Haikala, L. K.; Gahm, G. F.

    2017-09-01

    Context. The Rosette nebula is an H II region ionized mainly by the stellar cluster NGC 2244. Elephant trunks, globules, and globulettes are seen at the interface where the H II region and the surrounding molecular shell meet. Aims: We have observed a field in the northwestern part of the Rosette nebula where we study the small globules protruding from the shell. Our aim is to measure their properties and study their star-formation history in continuation of our earlier study of the features of the region. Methods: We imaged the region in broadband near-infrared (NIR) JsHKs filters and narrowband H2 1-0 S(1), Pβ, and continuum filters using the SOFI camera at the ESO/NTT. The imaging was used to study the stellar population and surface brightness, create visual extinction maps, and locate star formation. Mid-infrared (MIR) Spitzer IRAC and WISE and optical NOT images were used to further study the star formation and the structure of the globules. The NIR and MIR observations indicate an outflow, which is confirmed with CO observations made with APEX. Results: The globules have mean number densities of 4.6 × 104 cm-3. Pβ is seen in absorption in the cores of the globules where we measure visual extinctions of 11-16 mag. The shell and the globules have bright rims in the observed bands. In the Ks band 20 to 40% of the emission is due to fluorescent emission in the 2.12 μmH2 line similar to the tiny dense globulettes we studied earlier in a nearby region. We identify several stellar NIR excess candidates and four of them are also detected in the Spitzer IRAC 8.0 μm image and studied further. We find an outflow with a cavity wall bright in the 2.124 μmH2 line and at 8.0 μm in one of the globules. The outflow originates from a Class I young stellar object (YSO) embedded deep inside the globule. An Hα image suggests the YSO drives a possible parsec-scale outflow. Despite the morphology of the globule, the outflow does not seem to run inside the dusty fingers

  20. Anticariogenic and phytochemical evaluation of Eucalyptus globules Labill.

    Science.gov (United States)

    Ishnava, Kalpesh B.; Chauhan, Jenabhai B.; Barad, Mahesh B.

    2012-01-01

    In the present study, in vitro anticariogenic potential of ethyl acetate, hexane and methanol and aqueous extracts of plant leaves of Eucalyptus globules Labill. were evaluated by using four cariogenic bacteria, Lactobacillus acidophilus, Lactobacillus casei, Staphylococcus aureus and Streptococcus mutans. Agar well diffusion method and minimum inhibitory concentration (MIC) were used for this purpose. The ethyl acetate extracted fraction of plant leaves showed good inhibitory effects against all selected bacteria. In Eucalyptus globules, hexane and ethyl acetate extracts found highly effective against, Lactobacillus acidophilus with MIC value of 0.031 and 0.062 mg/mL, respectively. Qualitative phytochemical investigation of above extracts showed the presence of alkaloids, phenolic compounds, steroids, cardiac glycosides and terpenes. Based on the MIC value and bioautography, ethyl acetate of plant leaf was selected for further study. Further investigation on the structure elucidation of the bioactive compound using IR, GC-MS and NMR techniques revealed the presence of alpha-farnesene, a sesquiterpene. Eucalyptus globules plant leaf extracts have great potential as anticariogenic agents that may be useful in the treatment of oral disease. PMID:23961222

  1. Sulfur globule oxidation in green sulfur bacteria is dependent on the dissimilatory sulfite reductase system

    DEFF Research Database (Denmark)

    Holkenbrink, Carina; Ocón Barbas, Santiago; Mellerup, Anders

    2011-01-01

    Green sulfur bacteria oxidize sulfide and thiosulfate to sulfate with extracellular globules of elemental sulfur as intermediate. Here we investigated which genes are involved in the formation and consumption of these sulfur globules in the green sulfur bacterium Chlorobaculum tepidum. We show...... that sulfur globule oxidation is strictly dependent on the dissimilatory sulfite reductase (DSR) system. Deletion of dsrM/CT2244 or dsrT/CT2245 or the two dsrCABL clusters (CT0851-CT0854, CT2247-2250) abolished sulfur globule oxidation and prevented formation of sulfate from sulfide, whereas deletion of dsr...

  2. Dust in the outer layers of the Barnard 5 globule

    Science.gov (United States)

    Il'in, V. B.; Efimov, Yu S.; Khudyakova, T. N.; Prokopjeva, M. S.; Varivoda, V. V.

    2018-04-01

    We present the results of our UBVRI polarimetric observations of a dozen stars located close to the well-studied Bok globule Barnard 5 (B5), with several of the stars being seen through its outer layers (with AV up to ˜3 mag). Using recent astrometric, spectroscopic and photometric surveys, we estimate the distance, spectral class and visual extinction for the observed stars and find that the results are in a good agreement with the available 3D extinction maps. We use a two-layer dust model of interstellar polarization towards B5, in which the layer closer to us is an extension of the Taurus cloud complex, and the farther one (including B5 and its halo) is related to the Perseus cloud complex (d ≈ 280-350 pc). Using spectral, photometric and polarimetric data on about 30 additional stars, we estimate the parameters of the former layer as λmax ≈ 0.56 μm, Pmax ≈ 0.7 per cent, θ ≈ 50°, AV ≈ 0.7 mag, and show that the observed wavelength dependence of the position angle for the stars observed generally agrees with the two-layer model. We find that when the stars are seen through the globule layers with AV = 2-3 mag, λmax ≈ 0.6-0.8 μm, which differs significantly from the λmax = 0.52-0.58 μm obtained by us for the diffuse interstellar medium in the direction of B5. We discuss the correlation of λmax with the optical thickness into the globule as well as other correlations of the extinction and polarization parameters.

  3. In situ observation of D-rich carbonaceous globules embedded in NWA 801 CR2 chondrite

    Science.gov (United States)

    Hashiguchi, Minako; Kobayashi, Sachio; Yurimoto, Hisayoshi

    2013-12-01

    Eighty-five D-rich carbonaceous particles were identified in the matrix of the NWA 801 CR2 chondrite using isotope microscopy. The occurrence of 67 D-rich carbonaceous particles was characterized using secondary electron microscopy combined with X-ray elemental mapping. The close association of H and C, and D-enrichment suggests that the D-rich carbonaceous particles correspond to organic matter. The D-rich organic particles were scattered ubiquitously throughout the matrix at a concentration of approximately 660 ppm. The morphology of the D-rich carbonaceous particles is globular up to about 1 μm in diameter and is classified into four types: ring globules, round globules, irregular-shaped globules, and globule aggregates. The ring globules are ring-shaped organic matter containing silicate and/or oxide, with or without a void in the center. This is the first report of silicate and oxide grains surrounded by D-rich organic matter. The globule aggregates are composed of several D-rich organic globules mixed with silicates. Morphology of ring globules is very similar to core-mantle grain produced in the molecular cloud or in the outer solar nebula inferring by astronomy, suggesting that the organic globules have formed by UV photolysis in the ice mantle. Silicates or oxides attached to D-rich organic globules are the first observation among chondrites so far and may be unique nature of CR2 chondrites. The hydrogen isotopic compositions of the ring globules, round globules, irregular-shaped globules, and globule aggregates are δD = 3000-4800, 2900-8100, 2700-11,000, and 2500-11,000‰, respectively. Variations of D/H ratio of these organic globules seemed to be attributed to variations of D/H ratio of the organic radicals or differences of content of the D-rich organic radicals. There are no significant differences in the hydrogen isotopic compositions among the four types of D-rich carbonaceous matter. The D-enrichments suggest that these organic globules have

  4. Topological switching between an alpha-beta parallel protein and a remarkably helical molten globule.

    NARCIS (Netherlands)

    Nabuurs, S.M.; Westphal, A.H.; Toorn, M. aan den; Lindhoud, S.; Mierlo, C.P. van

    2009-01-01

    Partially folded protein species transiently exist during folding of most proteins. Often these species are molten globules, which may be on- or off-pathway to native protein. Molten globules have a substantial amount of secondary structure but lack virtually all the tertiary side-chain packing

  5. Topological switching between an a-ß parallel protein and a remarkably helical molten globule.

    NARCIS (Netherlands)

    Nabuurs, S.M.; Westphal, A.H.; Toorn, aan den M.; Lindhoud, S.; Mierlo, van C.P.M.

    2009-01-01

    Partially folded protein species transiently exist during folding of most proteins. Often these species are molten globules, which may be on- or off-pathway to native protein. Molten globules have a substantial amount of secondary structure but lack virtually all the tertiary side-chain packing

  6. Chromatin in fractal globule state: evidence from comet assay

    Directory of Open Access Journals (Sweden)

    Afanasieva K. S.

    2015-04-01

    Full Text Available At higher order levels chromatin is organized into loops that appear as a result of contacts between distant loci. The aim of this work was to investigate the length distribution of the DNA loops in nucleoids obtained after lysis of either whole cells or isolated cell nuclei. Methods. We used single cell gel electrophoresis to analyze the kinetics of the DNA loop migration from the two nucleoid types. Results. The kinetics of the DNA exit was found to have specific features for the two types of nucleoids. At the same time, in both cases, the DNA amount in the electrophoretic track depends linearly on the length of the longest loops in the track. Conclusions. We have concluded that for the loops up to ~ 100 kb the length distribution appears to be consistent with the fractal globule organization.

  7. Intramedullary fat globules related to bone trauma: a new MR imaging finding

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Adelaine; Grando, Higor; Fliszar, Evelyne; Pathria, Mini; Resnick, Donald [UCSD Radiology, Musculoskeletal Division, San Diego, CA (United States); Chang, Eric Y. [UCSD Radiology, Musculoskeletal Division, San Diego, CA (United States); VA San Diego Healthcare System, Department of Radiology, San Diego, CA (United States)

    2014-12-15

    The purpose of this study is to describe intraosseous fat globules related to bone trauma that are detectable with magnetic resonance imaging (MRI), to define the relationship of this finding to fracture and bone contusion, to establish the frequency and associated findings. A proposed pathogenesis is presented. We retrospectively reviewed 419 knee MRI examinations in patients with a history of recent injury and MRI findings of fracture or bone contusion. As a control population, 268 knee MRI examinations in patients without MRI findings of recent bone injury were also reviewed. Eight of 419 (1.9 %) patients with acute or subacute knee injury with positive findings of osseous trauma on MRI demonstrated intraosseous fat globules. The mean age of patients with fat globules was greater than that of those without fat globules, and the finding was more commonly seen in women. Fat globules were hyperintense to the normal fatty marrow present elsewhere in the bone on TI-weighted imaging and had a surrounding halo of high signal intensity on fluid-sensitive imaging. Intramedullary fat globules related to bone injury visible on MRI are thought to be due to coalesced fat released by the necrosis of fatty marrow cells. The pathogenesis is supported by histologic studies of fat globules related to osteomyelitis, bone contusions and fractures. As the medullary cavity of long bones in older patients contains more fat than hematopoetic bone marrow, it is likely that this finding is more common with advancing age. (orig.)

  8. Phagocytosis mechanism of apoptotic granulosa cells regulated by milk-fat globule-EGF factor 8.

    Science.gov (United States)

    Naka, Mayumi; Kusakabe, Ken; Takeshita, Ai; Nakagawa, Hiroshi; Ito, Yuko; Shibata, Masa-Aki; Otsuki, Yoshinori

    2009-09-01

    In the process of ovary sexual maturation, most immature ovarian follicles degrade into atretic follicles accompanied by apoptosis in granulosa cells. Macrophages can recognize apoptotic cells through specific binding with phosphatidylserine (PS), exposed on the surface of apoptotic cells, which is mediated by milk-fat globule-EGF factor 8 (MFG-E8). In the present research, we examined the involvement of the MFG-E8-dependent phagocytosis system in the atretic follicles of developing mouse ovaries. The number of atretic follicles and DNA-fragmented granulosa cells significantly increased in B6C3F1 mice during 2 to 6 weeks. Chromatin-condensed granulosa cells were engulfed by macrophages, which existed in the stroma or atretic follicles, or by neighboring normal granulosa cells. MFG-E8 mRNA increased in ovaries during 2 to 6 weeks, and immunoreactivity of MFG-E8 was detected at the surface of apoptotic cells existing around the antrum. Immunoelectron microscopic study revealed MFG-E8-positive signals on the membrane of apoptotic cells near macrophages, but apoptotic cells engulfed by neighboring granulosa cells showed few signals. Anti-Fas antibody elevated the annexin-V-positive reaction in isolated granulosa cells from 3-week-old mouse ovaries. MFG-E8 seems to act on the phagocytosis of apoptotic granulosa cells via macrophages and contribute to the regression process of atretic follicles.

  9. Purification of MUC1 from bovine milk-fat globules and characterization of a corresponding full-length cDNA clone

    DEFF Research Database (Denmark)

    Pallesen, Lone Tjener; Andersen, Mikkel Holmen; Nielsen, Rune L.

    2001-01-01

    The highly glycosylated protein MUC1 was purified from bovine milk-fat globule membranes by a procedure involving detergent extraction, ion-exchange chromatography and reverse-phase chromatography. The identity of the purified mucin protein was confirmed by N-terminal sequencing and partial amino...... acid sequences obtained by peptide mapping. The complete amino acid sequence of MUC1 was determined by cloning and sequencing the corresponding bovine mammary gland cDNA, which was shown to encode a protein of 580 amino acid residues comprising a cleavable signal peptide of 22 residues. The deduced...

  10. Influence of Mucilage Viscosity On The Globule Structure And Stability Of Certain Starch Emulsions

    Directory of Open Access Journals (Sweden)

    Uhumwangho MU

    2005-05-01

    Full Text Available A study was carried out to determine the influence of mucilage viscosity on the globule structure (i.e. size and number of certain starch emulsions. The starches investigated were cassava, potato and maize. The emulsions were prepared by mixing the starch mucilage of a predetermined concentration 4%w/v with arachis oil in the ratio 50:50, using a silverson mixer fitted with a dispersator head. The emulsions were stored at room temperature (28±20C for 7 days. Changes in globule size were monitored by photomicroscopy. Viscosities of the mucilage and those of resulting emulsions were determined using a capillary flow method. The viscosities of the emulsions expressed as time of flow (seconds, were 680 (cassava starch, 369 (potato starch and 270 (Maize starch, and for the mucilage 510 (cassava, 336 (potato and 248 (maize. The corresponding mean globule sizes of the fresh emulsions were (µm 28±6, 42±6 and 45±5 respectively. The increase in globule size during storage (measure of globule coalescence rate was 1.8±0.2µm day -1 (cassava, 3.5±0.2µm day -1 (potato and 4.6±0.3µm day -1 (maize. Thus, a higher viscosity of the dispersion medium is associated with the production of finer and more stable emulsions.

  11. The Effect of Sterilization on Size and Shape of Fat Globules in Model Processed Cheese Samples

    Directory of Open Access Journals (Sweden)

    B. Tremlová

    2006-01-01

    Full Text Available Model cheese samples from 4 independent productions were heat sterilized (117 °C, 20 minutes after the melting process and packing with an aim to prolong their durability. The objective of the study was to assess changes in the size and shape of fat globules due to heat sterilization by using image analysis methods. The study included a selection of suitable methods of preparation mounts, taking microphotographs and making overlays for automatic processing of photographs by image analyser, ascertaining parameters to determine the size and shape of fat globules and statistical analysis of results obtained. The results of the experiment suggest that changes in shape of fat globules due to heat sterilization are not unequivocal. We found that the size of fat globules was significantly increased (p < 0.01 due to heat sterilization (117 °C, 20 min, and the shares of small fat globules (up to 500 μm2, or 100 μm2 in the samples of heat sterilized processed cheese were decreased. The results imply that the image analysis method is very useful when assessing the effect of technological process on the quality of processed cheese quality.

  12. Globules, dark clouds, and low mass pre-main sequence stars

    International Nuclear Information System (INIS)

    Hyland, A.R.

    1981-01-01

    The current observational and theoretical literature on Bok globules and their relationship to star formation is reviewed. Recent observations of globules at optical, infrared, and far infrared wavelengths are shown to provide important constraints on their structure and evolutionary status, and the suggestion that many globules are gravitationally unstable is seriously questioned. Dark clouds associated with T associations are well-known sites of recent and continuing star formation. In recent years molecular observations and far infrared surveys have provided maps of such regions from which possible sites of star formation may be identified. Optical (Hα) and near infrared surveys have enabled a clear identification of pre-main sequence (PMS) objects within the clouds. Methods of distinguishing these from background objects and the nature of their infrared excesses are examined in the light of recent observations in the near and far infrared. The perennial question as to the existence of anomalous reddening within dark clouds is also investigated. (Auth.)

  13. Organic Globules from the Cold Far Reaches of the Proto-Solar Disk

    Science.gov (United States)

    Taylor, G. J.

    2007-01-01

    Keiko Nakamura-Messenger and colleagues at the NASA Johnson Space Center in Houston, Texas, studied minute globules of organic material in the Taglish Lake carbonaceous chondrite. This meteorite was collected soon after it fell, so is fresh and likely to be uncontaminated with terrestrial organic compounds. Using microanalytical techniques the NASA team found that the globules had hydrogen and nitrogen isotopic compositions consistent with chemical reactions at strikingly frigid temperatures, only 10 to 20 K (-253 to -263 degrees C). Temperatures that low occur in cold, interstellar molecular clouds like the one that collapsed to form the Solar System or in the outermost part of the disk surrounding the Sun when it was forming. These organic globules might represent the type of prebiotic carbon compounds that were delivered to young Earth.

  14. Effects of Size and Stability of Native Fat Globules on the Formation of Milk Gel Induced by Rennet.

    Science.gov (United States)

    Luo, Jie; Wang, Yuhan; Guo, Huiyuan; Ren, Fazheng

    2017-03-01

    Rennet-induced gelation crucially impacts cheese structure. In this study, effects of the size and stability of native fat globules on the kinetics of rennet-induced coagulation were revealed by determining the caseinomacropeptide release rate and rheological properties of milk. Moreover, the mobility and stability of fat globules during renneting was revealed using diffusing wave spectroscopy and confocal laser scanning microscopy. By use of a 2-stage gravity separation combined centrifugation scheme, native fat globules were selectively separated into small (SFG, D 4,3 = 1.87 ± 0.02 μm) and large fat globules (LFG, D 4,3 = 5.65 ± 0.03 μm). The protein and fat content of SFG and LFG milk were then standardized to 3.2 g/100 mL and 1.2 g/100 mL, respectively. The milk containing different sized globules were then subjected to renneting experiments in the laboratory. Reduction of globule size accelerated the aggregation of casein micelles during renneting, giving a shorter gelation time and earlier 1/l * change. The gel produced from LFG milk was broken due to coalescent fat globules and generated coarser gel strands compared to the finer strands formed with SFG milk. Structural differences were also confirmed with a higher final storage modulus of the curd made from SFG milk than that from the LFG. In conclusion, the size of fat globules affects the aggregation of casein micelles. Moreover, fat globule coalescence and creaming during renneting, also affects the structure of the rennet gel. A better understanding of the size of globules effect on milk gelation could lead to the development of cheese with specific properties. © 2017 Institute of Food Technologists®.

  15. Star-Formation in Free-Floating Evaporating Gaseous Globules

    Science.gov (United States)

    Sahai, Raghvendra

    How the evolutionary details of the star formation process (e.g., IMF, binary fraction, star formation efficiency, total extent and mass of star clusters) depend on the local environment is a major question in astrophysics. Massive stars have a strong feedback effect on their environment, via their winds, UV radiation, and ultimately, supernova blast waves, all of which can alter the likelihood for the formation of stars in nearby clouds and limit the accretion process of nearby protostars. But the complex structural make-up (revealed in exquisite detail by many modern studies using HST, Spitzer, WISE, & Herschel) of star-forming clouds in massive star-forming regions (MSFRs) has made it difficult, in spite of decades of study, to reach definitive, quantitative conclusions about the various physical processes at play in producing ``triggered" star formation. All of these issues can now be addressed using a newly recognized class of stellar nurseries embedded within giant HII regions: free-floating Evaporating Gaseous Globules having cometary shapes (frEGGs). We serendipitously discovered two frEGGs in the Cygnus massive star-forming region with HST. Our preliminary exmaination of the Spitzer archive has revealed a potentially much larger number. We used molecular-line observations showing the presence of dense clouds with total masses of cold molecular gas exceeding 0.5 to a few Msun associated with these objects, thereby disproving the initial hypothesis based on their morphology that these were similar to the proplyds (cometary-shaped photoevaporating protoplanetary disks) found in Orion (Sahai et al. 2012a,b). By virtue of their distinct, isolated morphologies, frEGGS offer us an exciting, new "clean-cut" probe of the star formation process in the vicinity of massive star clusters. And finally, frEGGs offer us an opportunity to study the earliest analogs of the physical environment where our Sun was born, since, like frEGGs, the protosolar nebula is believed to

  16. About iron globules formed at cooling of iron-contained plasma

    Science.gov (United States)

    Bulina, N. V.; Gromyko, A. I.; Bondarenko, G. V.; Marachevsky, A. V.; Chekanova, L. A.; Prokof'ev, D. E.; Churilov, G. N.

    2006-12-01

    This paper is devoted to the investigation of iron globules that are formed during cooling of the iron-carbon-helium plasma and as a result of destruction of a natural ball lightning. Scanning electron microscopy, X-ray fluorescence, X-ray diffraction, and ferromagnetic resonance investigations were carried out. The magnetization values of the samplers were determined.

  17. Infrared study of new star cluster candidates associated to dusty globules

    Science.gov (United States)

    Soto King, P.; Barbá, R.; Roman-Lopes, A.; Jaque, M.; Firpo, V.; Nilo, J. L.; Soto, M.; Minniti, D.

    2014-10-01

    We present results from a study of a sample of small star clusters associated to dusty globules and bright-rimmed clouds that have been observed under ESO/Chile public infrared survey Vista Variables in the Vía Láctea (VVV). In this short communication, we analyse the near-infrared properties of a set of four small clusters candidates associated to dark clouds. This sample of clusters associated to dusty globules are selected from the new VVV stellar cluster candidates developed by members of La Serena VVV Group (Barbá et al. 2014). Firstly, we are producing color-color and color-magnitude diagrams for both, cluster candidates and surrounding areas for comparison through PSF photometry. The cluster positions are determined from the morphology on the images and also from the comparison of the observed luminosity function for the cluster candidates and the surrounding star fields. Now, we are working in the procedures to establish the full sample of clusters to be analyzed and methods for subtraction of the star field contamination. These clusters associated to dusty globules are simple laboratories to study the star formation relatively free of the influence of large star-forming regions and populous clusters, and they will be compared with those clusters associated to bright-rimmed globules, which are influenced by the energetic action of nearby O and B massive stars.

  18. Coil–globule transition of a polymer involved in excluded-volume interactions with macromolecules

    International Nuclear Information System (INIS)

    Odagiri, Kenta; Seki, Kazuhiko

    2015-01-01

    Polymers adopt extended coil and compact globule states according to the balance between entropy and interaction energies. The transition of a polymer between an extended coil state and compact globule state can be induced by changing thermodynamic force such as temperature to alter the energy/entropy balance. Previously, this transition was theoretically studied by taking into account the excluded-volume interaction between monomers of a polymer chain using the partition function. For binary mixtures of a long polymer and short polymers, the coil-globule transition can be induced by changing the concentration of the shorter polymers. Here, we investigate the transition caused by short polymers by generalizing the partition function of the long polymer to include the excluded-volume effect of short polymers. The coil-globule transition is studied as a function of the concentration of mixed polymers by systematically varying Flory’s χ-parameters. We show that the transition is caused by the interplay between the excluded-volume interaction and the dispersion state of short polymers in the solvent. We also reveal that the same results can be obtained by combining the mixing entropy and elastic energy if the volume of a long polymer is properly defined

  19. Na-Fe-Phosphate Globules in Impact Metal-Troilite Associations of Chelyabinsk Meteorite

    Science.gov (United States)

    Sharygin, V. V.; Karmanov, N. S.; Podgornykh, N. M.

    2016-08-01

    Multi- and monophase phosphate globules have been found in the impact metal-troilite aggregates of the Chelyabinsk chondrite. Their phase composition varies and they contain galileiite, sarcopside, graftonite and Na-Fe-phosphate Na2(Fe,Mn)5(PO4)4.

  20. Effect of galactose on acid induced molten globule state of Soybean Agglutinin: Biophysical approach

    Science.gov (United States)

    Alam, Parvez; Naseem, Farha; Abdelhameed, Ali Saber; Khan, Rizwan Hasan

    2015-11-01

    In the present study the formation of molten globule-like unfolding intermediate Soybean Agglutinin (SBA) in acidic pH range has been established with the help of acrylamide quenching, intrinsic fluorescence, ANS fluorescence measurement, far UV CD and dynamic light scattering measurement. A marked increase in ANS fluorescence was observed at pH 2.2. Ksv of acrylamide quenching was found to be higher at pH 2.2 than that of native SBA at pH 7. Far UV CD spectra of pH induced state suggest that SBA shows significant retention of secondary structure closure to native. Hydrodynamic radius of SBA at pH 2.2 was found be more as compared to native state and also in other pH induced states. Further we checked the effect of galactose on the molten globule state of SBA. This study suggests that SBA exist as molten globule at pH 2.2 and this study will help in acid induced molten globule state of other proteins.

  1. Topological switching between an alpha-beta parallel protein and a remarkably helical molten globule.

    Science.gov (United States)

    Nabuurs, Sanne M; Westphal, Adrie H; aan den Toorn, Marije; Lindhoud, Simon; van Mierlo, Carlo P M

    2009-06-17

    Partially folded protein species transiently exist during folding of most proteins. Often these species are molten globules, which may be on- or off-pathway to native protein. Molten globules have a substantial amount of secondary structure but lack virtually all the tertiary side-chain packing characteristic of natively folded proteins. These ensembles of interconverting conformers are prone to aggregation and potentially play a role in numerous devastating pathologies, and thus attract considerable attention. The molten globule that is observed during folding of apoflavodoxin from Azotobacter vinelandii is off-pathway, as it has to unfold before native protein can be formed. Here we report that this species can be trapped under nativelike conditions by substituting amino acid residue F44 by Y44, allowing spectroscopic characterization of its conformation. Whereas native apoflavodoxin contains a parallel beta-sheet surrounded by alpha-helices (i.e., the flavodoxin-like or alpha-beta parallel topology), it is shown that the molten globule has a totally different topology: it is helical and contains no beta-sheet. The presence of this remarkably nonnative species shows that single polypeptide sequences can code for distinct folds that swap upon changing conditions. Topological switching between unrelated protein structures is likely a general phenomenon in the protein structure universe.

  2. Coil-Globule Transition of PNIPAM in Non-Ionic Surfactant Mesophase

    Science.gov (United States)

    Jijo, V. J.; Sharma, K. P.; Mathew, R.; Rajamohanan, P. R.; Guruswamy, K.

    2010-03-01

    We investigate the Coil-Globule transition of linear poly N-isopropylacrylamide (PNIPAM) in the hexagonal (H1) mesophase of a non ionic surfactant, C12E9 in water, by Turbidimetry, NMR and SAXS. For aqueous PNIPAM, the LCST (coil-globule transition temperature), TPNIPAM, is 35 C, whereas the H1 phase transitions to a micellar phase at a temperature, THI, of 45 C. As PNIPAM is added to the C12E9/H2O system; depending on the ratio of C12E9:H2O, TPNIPAM changes. It is observed that at 42wt% of C12E9 (viz. 58wt% water; micellar phase), the TPNIPAM is 33 C. At 44wt% of C12E9 (viz. 56wt% water), the H1 phase forms and the the coil-globule transition for PNIPAM starts at 28 C. For 50wt% C12E9, the transition starts from 13 C and for 60wt% C12E9 in water, PNIPAM does not even shows the phase transition even as below as 5 C. It is observed using optical microscopy that the PNIPAM is trapped at the domain boundaries of the H1 phase. The decrease in the coil globule transition temperature, TPNIPAM, is not only because of the hydrophobic interactions but also due to the competition between polymer and C12E9 for water in the H1 phase. The inability of PNIPAM to become a complete globule at higher temperature may be due to the adsorption of C12E9.

  3. Influence of seasonal variation and ultra high temperature processing on lipid profile and fat globule structure of Swedish cow milk.

    Science.gov (United States)

    Lu, Jing; Pickova, Jana; Vázquez-Gutiérrez, José L; Langton, Maud

    2018-01-15

    To investigate the effects of seasonal variations and processing on cow milk fat, raw milk collected in six individual months and corresponding ultra high temperature (UHT) milk were analyzed. Similar seasonal variations in lipid classes and fatty acid composition were found in raw and UHT milk. Under commercial processing, lipid content was standardized to approximately 1.5% in UHT milk. Decreased diameter of fat droplets (around 1µm) and thinner globule membranes were observed, as revealed using confocal laser scanning microscopy (CLSM). The distribution of lipid classes was modified with a decreased proportion of triacylglycerol accompanied by the increase of phospholipids and free fatty acids. Saturated fatty acids C12:0 and C14:0, trans-fatty acids including conjugated linoleic acid (CLA), polyunsaturated fatty acids C18:2(n-6) and C18:3(n-3), showed increased proportions in UHT milk. These results provide an indication of the effect of UHT processing on milk lipid properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Relationship between fat globule size and chemical and fatty acid composition of cow's milk in mid lactation

    Directory of Open Access Journals (Sweden)

    Cosima Scolozzi

    2010-01-01

    Full Text Available The milk in 57 Italian Fresian cows in mid lactation was analysed in order to define the relationship between some qualitative milk parameters and the size of milk fat globules. The study focused on the morphometric evaluation of milk fat globules, chemical parameteres and fatty acid composition of the milk. The results show that a prevalence of milk fat globules with a diameter 6 um was associated (P<0.01 with greater milk yield nad a higher percentage of lactose, non-fat dry matter and ash............

  5. Relationship between fat globule size and chemical and fatty acid composition of cow's milk in mid lactation

    Directory of Open Access Journals (Sweden)

    Mina Martini

    2006-01-01

    Full Text Available The milk in 57 Italian Fresian cows in mid lactation was analysed in order to define the relationship between some qualitative milk parameters and the size of milk fat globules. The study focused on the morphometric evaluation of milk fat globules, chemical parameteres and fatty acid composition of the milk. The results show that a prevalence of milk fat globules with a diameter 6 um was associated (P<0.01 with greater milk yield nad a higher percentage of lactose, non-fat dry matter and ash............

  6. Atomistic simulation for coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate).

    Science.gov (United States)

    Min, Sa Hoon; Kwak, Sang Kyu; Kim, Byeong-Su

    2015-03-28

    The coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) in aqueous solution was investigated by all-atomistic molecular dynamics simulations. The polymer consistent force field (PCFF) was applied to the PDMAEMA model with a proper protonation state. The structural analysis indicates a distinct difference in the hydration state of particular functional groups of PDMAEMA as well as in the conformational state of PDMAEMA below and above the lower critical solution temperature (LCST). In particular, by monitoring the motion of water molecules, we observe that water molecules in the vicinity of the carbonyl group are relatively restricted to the motion in the globule state due to the extended relaxation time of hydrogen bonds among water molecules. The degree of protonation was also adjusted to study the effect of protonation on the conformational state of PDMAEMA.

  7. A novel isolation strategy for obtaining crude membrane vesicles from bovine skim milk

    DEFF Research Database (Denmark)

    Blans, Kristine; Larsen, Lotte Bach; Wiking, Lars

    2014-01-01

    Bovine milks content of phospholipid membranes have largely been explored in the cream fraction, and known as the milk fat globule membrane that surrounds fat droplets. In skim milk, the population of phospholipid membranes is reported to constitute membrane vesicles with a soluble content known...... as exosomes and microvesicles. These vesicles contain various types of RNAs and proteins, suggested to transfer health-promoting messages from mother to offspring. However, the variety of the vesicles in milk is less understood and, additionally, complicated by the complexity of more pronounced milk...... components. Here we present a novel strategy for a short, gentle and non-denaturing isolation of skim milk-derived membrane vesicles. Methods: Untreated fresh bovine milk was defatted to remove milk fat globules. The resulting skim milk was subjected to ultracentrifugation. The resulting ochre...

  8. X-ray microprobe measurements of the chemical compositions of ALH84001 carbonate globules

    International Nuclear Information System (INIS)

    Flynn, G.J.; Sutton, S.R.; Keller, L.P.

    2004-01-01

    We measured minor element contents of carbonate from ALH84001 and report trends in tbe Ca, V, Mn and Sr in carbonate and the associated magnetite bands. McKay et al. suggested that carbonate globules in the ALH84001 meteorite from Mars contained evidence consistent with the development of bacterial life early in the history of Mars. This result provoked an extensive study of the ALH84001 meteorite. More recently Thomas-Keprta et al. have published a study showing that the magnetite associated with carbonate rims are of the size and shape produced by terrestrial bacteria. This paper has revived interest in ALH84001. The typical ALH84001 carbonate globule consists of four regions: a core of Fe-rich carbonate, a thin magnetite-rich band, a rim of Mn-rich carbonate, and another thin magnetite-rich band. Trace element analysis of each of these phases may allow us to address several important questions about these carbonates: (1) The origin of the magnetite-rich bands in the ALH84001 carbonate globules. If the magnetites are derived from the underlying carbonate through thermal decomposition (as proposed by Golden et al.), then we expect to see 'inherited' trace elements in these magnetite bands. (2) The origin of the rim carbonate, by determining whether the carbonate in the core has the same trace elements as the rim carbonates. (3) The age of the rim carbonate. Borg et al. dated the formation of the rim carbonate using the Rb/Sr chronometer. Borg et al. performed their measurements on an aliquot of what they called a high-Rb, low-Sr carbonate separate from the rim. We previously measured the trace element contents of chips from core and rim carbonates from an ALH84001 carbonate globule using an X-Ray Microprobe on Beamline X26A at the National Synchrotron Light Source. These measurements showed the rim carbonate had a very low Rb content, with Sr>>Rb, inconsistent with the ∼5 ppm Rb reported by Borg et al. in the sample they dated by the Rb/Sr chronometer. The large

  9. Atomic force microscopy of the intervessel pit membrane in the stem of Sapium sebiferum (Euphorbiacea)

    Science.gov (United States)

    Thomas C. Pesacreta; Leslie H. Groom; Timothy G. Rials

    2005-01-01

    Sapwood and juvenile wood of Sapium sebiferum (Euphorbiacea) was collected during 2000-2002. In air-dried vessel elements, the surface of pit membranes (PMs) in the outermost growth ring was coated with plaque-like or interstitial material that was 2-5 nm thick. This coating was phase dark and overlaid a phase bright layer of globules and...

  10. Identification of ABCA1 and ABCG1 in milk fat globules and mammary cells--implications for milk cholesterol secretion.

    Science.gov (United States)

    Mani, O; Körner, M; Ontsouka, C E; Sorensen, M T; Sejrsen, K; Bruckmaier, R M; Albrecht, C

    2011-03-01

    The ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 play an important role in cellular cholesterol homeostasis, but their function in mammary gland (MG) tissue remains elusive. A bovine MG model that allows repeated MG sampling in identical animals at different functional stages was used to test whether 1) ABCA1 and ABCG1 protein expression and subcellular localization in mammary epithelial cells (MEC) change during the pregnancy-lactation cycle, and 2) these 2 proteins were present in milk fat globules (MFG). Expression and localization in MEC were investigated in bovine MG tissues at the end of lactation, during the dry period (DP), and early lactation using immunohistochemical and immunofluorescence approaches. The presence of ABCA1 and ABCG1 in MFG isolated from fresh milk was determined by immunofluorescence. The ABCA1 protein expression in MEC, expressed as arbitrary units, was higher during the end of lactation (12.2±0.24) and the DP (12.5±0.22) as compared with during early lactation (10.2±0.65). In contrast, no significant change in ABCG1 expression existed between the stages. Throughout the cycle, ABCA1 and ABCG1 were detected in the apical (41.9±24.8 and 49.0±4.96% of cows, respectively), basal (56.2±28.1 and 54.6±7.78% of cows, respectively), or entire cytoplasm (56.8±13.4 and 61.6±14.4% of cows, respectively) of MEC, or showed combined localization. Unlike ABCG1, ABCA1 was absent at the apical aspect of MEC during early lactation. Immunolabeling experiments revealed the presence of ABCA1 and ABCG1 in MFG membranes. Findings suggest a differential, functional stage-dependent role of ABCA1 and ABCG1 in cholesterol homeostasis of the MG epithelium. The presence of ABCA1 and ABCG1 in MFG membranes suggests that these proteins are involved in cholesterol exchange between MEC and alveolar milk. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. Fitting a Turbulent Cloud Model to CO Observations of Starless Bok Globules

    Science.gov (United States)

    Hegmann, M.; Hengel, C.; Röllig, M.; Kegel, W. H.

    We present observations of five starless Bok globules in transitions of 12CO (J=2-1 and {J=3-2}), 13CO (J=2-1), and C18O (J=2-1) which have been obtained at the Heinrich-Hertz-Telescope. For an analysis of the data we use the model of Kegel et al. (see e.g. Piehler & Kegel 1995, A&A 297, 841; Hegmann & Kegel 2000, A&A 359, 405) which describes an isothermal sphere stabilized by turbulent and thermal pressure. This approach deals with the full NLTE radiative transfer problem and accounts for a turbulent velocity field with finite correlation length. By a comparison of observed and calculated line profiles we are able not only to determine the kinetic temperature, hydrogen density and CO coloumn density of the globules, but also to study the properties of the turbulent velocity field, i.e. the variance of its one-point-distribution and its correlation length. We consider our model to be an alternative tool for the evaluation of molecular lines emitted by molecular clouds. The model assumptions are certainly closer to reality than the assumptions behind the standard evaluation models, as for example the LVG model. Our current study shows that that the results obtained from our model can differ significantly from those obtained from a LVG analysis.

  12. On urea's ability to stabilize the globule state of poly(N-isopropylacrylamide).

    Science.gov (United States)

    Pica, Andrea; Graziano, Giuseppe

    2016-06-07

    Experimental measurements have shown that urea decreases the temperature of the coil-to-globule collapse transition of poly(N-isopropylacrylamide), whereas tetramethylurea increases the collapse temperature [J. Am. Chem. Soc., 2009, 131, 9304]. These data indicate that urea is a stabilizing agent of the globule state in contrast to its denaturing action towards globular proteins. The effect of urea and tetramethylurea on the conformational stability of poly(N-isopropylacrylamide) is investigated by means of the theoretical approach developed to explain the existence of cold denaturation [Phys. Chem. Chem. Phys., 2010, 12, 14245; Phys. Chem. Chem. Phys., 2014, 16, 21755], and already used to rationalize the effect of sodium salts on the collapse temperature [Phys. Chem. Chem. Phys., 2015, 17, 27750]. It is necessary to take into account the delicate trade-off between the increase in the magnitude of the solvent-excluded volume effect caused by urea and tetramethylurea addition to water, and the increase in the magnitude of the energetic interactions among the poly(N-isopropylacrylamide) surface and water and co-solvent molecules.

  13. Enzymatic Detoxication, Conformational Selection, and the Role of Molten Globule Active Sites*

    Science.gov (United States)

    Honaker, Matthew T.; Acchione, Mauro; Zhang, Wei; Mannervik, Bengt; Atkins, William M.

    2013-01-01

    The role of conformational ensembles in enzymatic reactions remains unclear. Discussion concerning “induced fit” versus “conformational selection” has, however, ignored detoxication enzymes, which exhibit catalytic promiscuity. These enzymes dominate drug metabolism and determine drug-drug interactions. The detoxication enzyme glutathione transferase A1–1 (GSTA1–1), exploits a molten globule-like active site to achieve remarkable catalytic promiscuity wherein the substrate-free conformational ensemble is broad with barrierless transitions between states. A quantitative index of catalytic promiscuity is used to compare engineered variants of GSTA1–1 and the catalytic promiscuity correlates strongly with characteristics of the thermodynamic partition function, for the substrate-free enzymes. Access to chemically disparate transition states is encoded by the substrate-free conformational ensemble. Pre-steady state catalytic data confirm an extension of the conformational selection model, wherein different substrates select different starting conformations. The kinetic liability of the conformational breadth is minimized by a smooth landscape. We propose that “local” molten globule behavior optimizes detoxication enzymes. PMID:23649628

  14. Interrupted hydrogen/deuterium exchange reveals the stable core of the remarkably helical molten globule of alpha-beta parallel protein flavodoxin.

    NARCIS (Netherlands)

    Nabuurs, S.M.; Mierlo, C.P. van

    2010-01-01

    Kinetic intermediates that appear early during protein folding often resemble the relatively stable molten globule intermediates formed by several proteins under mildly denaturing conditions. Molten globules have a substantial amount of secondary structure but lack virtually all tertiary side-chain

  15. Interrupted hydrogen/deuterium exchange reveals the stable core of the remarkably helical molten globule of a-ß parallel protein flavodoxin

    NARCIS (Netherlands)

    Nabuurs, S.M.; Mierlo, van C.P.M.

    2010-01-01

    Kinetic intermediates that appear early during protein folding often resemble the relatively stable molten globule intermediates formed by several proteins under mildly denaturing conditions. Molten globules have a substantial amount of secondary structure but lack virtually all tertiary side-chain

  16. The influence of casein haplotype on morphometric characteristics of fat globules and fatty acid composition of milk in Italian Holstein cows.

    Science.gov (United States)

    Perna, Annamaria; Intaglietta, Immacolata; Simonetti, Amalia; Gambacorta, Emilio

    2016-04-01

    The aim of this work was to investigate the effect of casein haplotypes (αS1-, β-, and κ-caseins) on morphometric characteristics of fat globules and fatty acid composition of Italian Holstein milk. Casein haplotypes were determined by isoelectric focusing; milk fat globule size was measured by using a fluorescence microscope; and fatty acid profile was determined by gas chromatography. Casein haplotype significantly affected the fat globule size, the percentage incidence of each globule size class on total measured milk fat globules, and fatty acid composition. A higher incidence of smaller milk fat globules was associated with the BB-A(2)A(2)-BB genotype (αS1-, β-, and κ-casein haplotypes, respectively), whereas small globules were not detected in BB-A(2)A(1)-AA milk, but that milk had the highest percentage of large globules. A higher content of monounsaturated fatty acids was associated with the BB-A(2)A(2)-AB genotype, whereas higher contents of conjugated linoleic acid and docosahexaenoic acid were detected in BB-A(1)A(1)-AA milk. Our results indicate that casein haplotype could affect fat characteristics and, therefore, the nutritional and technological quality of milk. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  17. The effects of low-molecular-weight emulsifiers in O/W-emulsions on microviscosity of non-solidified oil in fat globules and the mobility of emulsifiers at the globule surfaces

    DEFF Research Database (Denmark)

    Munk, Merete B.; Erichsen, Henriette Rifbjerg; Andersen, Mogens Larsen

    2014-01-01

    Electron Spin Resonance spectroscopy (ESR) was used to measure the mobility of the spin probe TEMPO in O/W-emulsions. This allowed determination of temperature-dependent microviscosity of the liquid fraction in lipid globules. Six hydrogenated palm kernel oil (HPKO) based emulsions containing...

  18. Effect of homogenization and heat treatment on the behavior of protein and fat globules during gastric digestion of milk.

    Science.gov (United States)

    Ye, Aiqian; Cui, Jian; Dalgleish, Douglas; Singh, Harjinder

    2017-01-01

    The effects of homogenization and heat treatment on the formation and the breakdown of clots during gastric digestion of whole milk were investigated using a human gastric simulator. Homogenization and heat treatment led to formation of coagula with fragmented and crumbled structures compared with the coagulum formed from raw whole milk, but a larger fraction of the protein and more fat globules were incorporated into the coagula induced by action of the milk-clotting enzyme pepsin. The fat globules in the whole milk appeared to be embedded in the clots as they formed. After formation of the clot, the greater numbers of pores in the structures of the clots formed with homogenized milk and heated whole milk led to greater rates of protein hydrolysis by pepsin, which resulted in faster release of fat globules from the clots into the digesta. Coalescence of fat globules occurred both in the digesta and within the protein clots no matter whether they were in homogenized or heated milk samples. The formation of clots with different structures and hence the changes in the rates of protein hydrolysis and the release of milk fat into the digesta in the stomach provide important information for understanding the gastric emptying of milk and the potential to use this knowledge to manipulate the bioavailability of fat and other fat-soluble nutrients in dairy products. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. Capturing molten globule state of α-lactalbumin through constant pH molecular dynamics simulations

    Science.gov (United States)

    Bhattacharjee, Nicholus; Rani, Pooja; Biswas, Parbati

    2013-03-01

    The recently developed methods of constant pH molecular dynamics directly captures the correlation between protonation and conformation to probe protein structure, function, and dynamics. In this work, we investigate the effect of pH on the conformational properties of the protein human α-lactalbumin. Constant pH simulations at both acidic and alkaline medium indicate the formation of the molten globule state, which is in accordance with the previous experimental observations (especially, in acidic medium). The size of the protein measured by its radius of gyration (RG) exhibits a marked increase in both acidic and alkaline medium, which matches with the corresponding experimentally observed value of RG found in the molten globule. The probability of native contacts is also considerably reduced at acidic and basic pH as compared to that of native structure crystallized at neutral pH. The mean fractal dimension D2 of the protein records a sharp increase in basic medium as compared to those in neutral and acidic solutions implying a significant pH induced conformational change. The mean square fluctuations of all residues of the entire protein are found to increase by several folds in both acidic and basic medium, which may be correlated with the normalized solvent accessibility of the residues indicating role of solvent accessible surface area on protein internal dynamics. The helices comprising the α-domain of the protein are moderately preserved in the acidic and alkaline pH. However, the β-sheet structures present in the β-domain are completely disrupted in both acidic as well as basic pH.

  20. Sequence charge decoration dictates coil-globule transition in intrinsically disordered proteins

    Science.gov (United States)

    Firman, Taylor; Ghosh, Kingshuk

    2018-03-01

    We present an analytical theory to compute conformations of heteropolymers—applicable to describe disordered proteins—as a function of temperature and charge sequence. The theory describes coil-globule transition for a given protein sequence when temperature is varied and has been benchmarked against the all-atom Monte Carlo simulation (using CAMPARI) of intrinsically disordered proteins (IDPs). In addition, the model quantitatively shows how subtle alterations of charge placement in the primary sequence—while maintaining the same charge composition—can lead to significant changes in conformation, even as drastic as a coil (swelled above a purely random coil) to globule (collapsed below a random coil) and vice versa. The theory provides insights on how to control (enhance or suppress) these changes by tuning the temperature (or solution condition) and charge decoration. As an application, we predict the distribution of conformations (at room temperature) of all naturally occurring IDPs in the DisProt database and notice significant size variation even among IDPs with a similar composition of positive and negative charges. Based on this, we provide a new diagram-of-states delineating the sequence-conformation relation for proteins in the DisProt database. Next, we study the effect of post-translational modification, e.g., phosphorylation, on IDP conformations. Modifications as little as two-site phosphorylation can significantly alter the size of an IDP with everything else being constant (temperature, salt concentration, etc.). However, not all possible modification sites have the same effect on protein conformations; there are certain "hot spots" that can cause maximal change in conformation. The location of these "hot spots" in the parent sequence can readily be identified by using a sequence charge decoration metric originally introduced by Sawle and Ghosh. The ability of our model to predict conformations (both expanded and collapsed states) of IDPs at

  1. Etude de l'effet de l'amodiaquine sur les globules rouges infectés ...

    African Journals Online (AJOL)

    Ces images sont ensuite utilisées pour étudier l'interaction du médicament avec les globules rouges en fonction des concentrations, en ayant recours à des techniques d'analyse multivariée telles que la classification hiérarchique, la méthode des k-moyennes et l'analyse en composante principale. Les résultats obtenus ...

  2. Filter-aided sample preparation with dimethyl labeling to identify and quantify milk fat globule membrane proteins.

    NARCIS (Netherlands)

    Lu, J.; Boeren, J.A.; Vries, de S.C.; Valenberg, van H.J.F.; Vervoort, J.J.M.; Hettinga, K.A.

    2011-01-01

    Bovine milk is a major nutrient source in many countries and it is produced at an industrial scale. Milk is a complex mixture of proteins, fats, carbohydrates, vitamins and minerals. The composition of the bovine milk samples can vary depending on the genetic makeup of the bovine species as well as

  3. ARE LARGE, COMETARY-SHAPED PROPLYDS REALLY (FREE-FLOATING) EVAPORATING GAS GLOBULES?

    International Nuclear Information System (INIS)

    Sahai, R.; Güsten, R.; Morris, M. R.

    2012-01-01

    We report the detection of strong and compact molecular line emission (in the CO J = 3-2, 4-3, 6-5, 7-6, 13 CO J = 3-2, HCN, and HCO + J = 4-3 transitions) from a cometary-shaped object (Carina-frEGG1) in the Carina star-forming region (SFR) previously classified as a photoevaporating protoplanetary disk (proplyd). We derive a molecular mass of 0.35 M ☉ for Carina-frEGG1, which shows that it is not a proplyd, but belongs to a class of free-floating evaporating gas globules (frEGGs) recently found in the Cygnus SFR by Sahai et al. Archival adaptive optics near-IR (Ks) images show a central hourglass-shaped nebula. The derived source luminosity (about 8-18 L ☉ ), the hourglass morphology, and the presence of collimated jets seen in Hubble Space Telescope images imply the presence of a jet-driving, young, low-mass star deeply embedded in the dust inside Carina-frEGG1. Our results suggest that the true nature of many or most such cometary-shaped objects seen in massive SFRs and previously labeled as proplyds has been misunderstood, and that these are really frEGGs.

  4. DISCOVERY OF A HOT CORINO IN THE BOK GLOBULE B335

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Muneaki; Oya, Yoko; López-Sepulcre, Ana; Watanabe, Yoshimasa; Yamamoto, Satoshi [Department of Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sakai, Nami [The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Ceccarelli, Cecilia; Lefloch, Bertrand; Kahane, Claudine [Universite de Grenoble Alpes, IPAG, F-38000 Grenoble (France); Caux, Emmanuel; Vastel, Charlotte [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Sakai, Takeshi [Department of Communication Engineering and Informatics, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Hirota, Tomoya [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Aikawa, Yuri [Center for Computational Science, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2016-10-20

    We report the first evidence of a hot corino in a Bok globule. This is based on ALMA observations in the 1.2 mm band toward the low-mass Class 0 protostar IRAS 19347+0727 in B335. Saturated complex organic molecules (COMs), CH{sub 3}CHO, HCOOCH{sub 3}, and NH{sub 2}CHO, are detected in a compact region within a few 10 au around the protostar. Additionally, CH{sub 3}OCH{sub 3}, C{sub 2}H{sub 5}OH, C{sub 2}H{sub 5}CN, and CH{sub 3}COCH{sub 3} are tentatively detected. Carbon-chain related molecules, CCH and c-C{sub 3}H{sub 2}, are also found in this source, whose distributions are extended over a scale of a few 100 au. On the other hand, sulfur-bearing molecules CS, SO, and SO{sub 2} have both compact and extended components. Fractional abundances of the COMs relative to H{sub 2} are found to be comparable to those in known hot corino sources. Though the COMs lines are as broad as 5–8 km s{sup −1}, they do not show obvious rotation motion in the present observation. Thus, the COMs mainly exist in a structure whose distribution is much smaller than the synthesized beam (0.″58 × 0.″52).

  5. Unified View on the Mean-Field Order of Coil-Globule Transition

    Science.gov (United States)

    Yang, Delian; Wang, Qiang

    2014-03-01

    It is well known that a polymer chain immersed in a small-molecule solvent undergoes the coil-globule transition (CGT) as the solvent quality changes. In the study of CGT, a mean-field theory, either of the Flory-type or the self-consistent field theory, has been commonly used; the transition order predicted by the mean-field theory, however, has been controversial. By examining the first- and second-order derivatives of the Helmholtz free energy with respect to the solvent equality, the continuity of which defines the transition order but has not been reported in the literature, we concluded that the mean-field CGT of a polymer chain of finite length N exhibits the type-I behavior; that is, it is either a first-order phase transition, a critical point, or a crossover depending on the location of the critical point. It becomes a second-order phase transition with respect to the solvent equality characterized by the Flory-Huggins parameter χ (or equivalently the second virial coefficient v or the temperature T) only in the limit of N --> ∞ . Even in this limit, it still has the type-I behavior with respect to vN 1 / 2 (or equivalently (1 - 2 χ) N 1 / 2). Financial support for this work was provided by NSF CAREER Award CBET-0847016, which is gratefully acknowledged.

  6. Milk fat globule is an alternative to mammary epithelial cells for gene expression analysis in buffalo.

    Science.gov (United States)

    Chen, Qiuming; Wu, Yanjun; Zhang, Mingyuan; Xu, Wenwen; Guo, Xiaoping; Yan, Xueyu; Deng, Haiying; Jiang, Qinyang; Yang, Xiurong; Lan, Ganqiu; Guo, Yafen; Qin, Guangsheng; Jiang, Hesheng

    2016-05-01

    Owing to the difficulty in obtaining mammary gland tissue from lactating animals, it is difficult to test the expression levels of genes in mammary gland. The aim of the current study was to identify if milk fat globule (MFG) in buffalo milk was an alternative to mammary gland (MG) and milk somatic cell (MSC) for gene expression analysis. Six buffalos in late lactation were selected to collect MFG and MSC, and then MG was obtained by surgery. MFG was stained with acridine orange to successfully visualise RNA and several cytoplasmic crescents in MFG. The total RNA in MFG was successfully isolated and the integrity was assessed by agarose gel electrophoresis. We analysed the cellular components in MFG, MG and MSC through testing the expression of cell-specific genes by qRT-PCR. The results showed that adipocyte-specific gene (AdipoQ) and leucocyte-specific genes (CD43, CSF1 and IL1α) in MFG were not detected, whereas epithelial cell marker genes (Keratin 8 and Keratin 18) in MFG were higher than in MSC and lower than in MG, fibroblast marker gene (vimentin) in MFG was significantly lower than in MG and MSC, milk protein genes (LALBA, BLG and CSN2) and milk fat synthesis-related genes (ACC, BTN1A1, FABP3 and FAS) in MFG were higher than in MG and MSC. In conclusion, the total RNA in MFG mainly derives from mammary epithelial cells and can be used to study the functional gene expression of mammary epithelial cells.

  7. Milk fat globule E-8 and interleukin 17 in systemic lupus erythematosus: partners in crime?

    Directory of Open Access Journals (Sweden)

    Lamiaa Madkour

    2016-02-01

    Full Text Available Objectives: Systemic lupus erythematosus (SLE is a multi-factorial, autoimmune disease with a wide array of manifestations. The pro-inflammatory cytokine interleukin (IL-17 has been implicated in the inflammatory response and tissue damage in SLE; however, its correlation with disease activity is still questionable. Meanwhile, efficient clearance of apoptotic cells is required for immune tolerance. An abnormally low or high level of milk fat globule (MFG-E8 can result in impaired apoptotic cell clearance and the subsequent autoimmune response. In this study, we endeavoured to compare the levels of MFG-E8 and IL-17 in SLE patients and healthy controls and to reveal the alleged association of these levels with SLE disease activity. Material and methods: Serum samples from 57 SLE patients and 30 healthy control subjects were examined for quantitation of MFG-E8 and IL-17 levels using ELISA. Systemic lupus erythematosus disease activity was calculated using the SLE Disease Activity Index (SLEDAI. Clinical manifestations and laboratory findings of the patients were also recorded. Results : We report that serum MFG-E8 levels were significantly elevated in the sera of SLE patients compared to healthy controls (p-value = 0.019. Likewise, IL-17 levels were higher in SLE patients (p-value < 0.001. A positive correlation was revealed between MFG-E8 level and proteinuria. Surprisingly, there was a poor correlation between disease activity and the levels of either IL-17 or MFG-E8. Conclusions : Although serum MFG-E8 and IL-17 levels were higher in SLE patients than in normal controls, our results indicate that they cannot accurately reflect the disease activity. Meanwhile, further studies are needed to assess MFG-E8 and IL-17 as potential therapeutic targets in SLE patients.

  8. Molten globule of hemoglobin proceeds into aggregates and advanced glycated end products.

    Directory of Open Access Journals (Sweden)

    Afshin Iram

    Full Text Available Conformational alterations of bovine hemoglobin (Hb upon sequential addition of glyoxal over a range of 0-90% v/v were investigated. At 20% v/v glyoxal, molten globule (MG state of Hb was observed by altered tryptophan fluorescence, high ANS binding, existence of intact heme, native-like secondary structure as depicted by far-UV circular dichroism (CD and ATR-FTIR spectra as well as loss in tertiary structure as confirmed by near-UV CD spectra. In addition, size exclusion chromatography analysis depicted that MG state at 20% v/v glyoxal corresponded to expanded pre-dissociated dimers. Aggregates of Hb were detected at 70% v/v glyoxal. These aggregates of Hb had altered tryptophan environment, low ANS binding, exposed heme, increased β-sheet secondary structure, loss in tertiary structure, enhanced thioflavin T (ThT fluorescence and red shifted Congo Red (CR absorbance. On incubating Hb with 30% v/v glyoxal for 0-20 days, advanced glycation end products (AGEs were detected on day 20. These AGEs were characterised by enhanced tryptophan fluorescence at 450 nm, exposure of heme, increase in intermolecular β-sheets, enhanced ThT fluorescence and red shift in CR absorbance. Comet assay revealed aggregates and AGEs to be genotoxic in nature. Scanning electron microscopy confirmed the amorphous structure of aggregates and branched fibrils of AGEs. The transformation of α-helix to β-sheet usually alters the normal protein to amyloidogenic resulting in a variety of protein conformational disorders such as diabetes, prion and Huntington's.

  9. Shocked and Scorched: Free-Floating Evaporating Gas Globules and Star Formation in Cygnus

    Science.gov (United States)

    Sahai, Raghvendra; Claussen, M. J.; Morris, M. R.

    2012-05-01

    We report molecular line observations of a new class of Free-floating Evaporating Gas Globules with tadpole shapes (i.e., FrEGGs), recently discovered in the Cygnus star-forming region. We serendipitously found two of these in an HST imaging survey, including one of the most prominent members of this class (IRAS20324+4057: the Tadpole). Our molecular-line observations, carried out with the Arizona Radio Observatory's mm-wave telescopes, include on-the-fly maps in the CO and 13CO J=2-1 lines as well as pointed observations in the J=3-2 line of the high-density tracers HCO+ and N2H+. These data show the presence of dense molecular cores with total masses of cold molecular gas exceeding one to a few Msun in almost all FrEGGs. Our radio continuum imaging of 3 FrEGGs, as well as Halpha images from the IPHAS survey reveal bright photo-ionized peripheries around these objects. We infer that FrEGGs are dense, star-forming molecular cores that originated in the Cygnus cloud and are now being photoevaporated by the ultraviolet radiation field of the Cyg OB2 cluster, and shaped by the ram pressure of strong wind sources. The extended tails in some of the largest objects show wiggles likely resulting from Kelvin-Helmoltz instabilities. We find evidence for non-thermal radio emission in the Tadpole, with the radio emission peaking strongly along the shock/ionization front at its head, possibly as a result of a compressed magnetic layer in this front that is interacting with cosmic rays associated with the Cyg OB2 association.

  10. Shocked and Scorched - Free-Floating Evaporating Gas Globules and Star Formation

    Science.gov (United States)

    Sahai, Raghvendra; Morris, Mark R.; Claussen, Mark J.

    2014-07-01

    Massive stars have a strong feedback effect on their environment, via their winds, UV radiation, and ultimately, supernova blast waves, all of which can alter the likelihood for the formation of stars in nearby clouds and limit the accretion process of nearby protostars. Free-floating Evaporating Gaseous Globules, or frEGGs, are a newly recognized class of stellar nurseries embedded within the giant HII regions found in massive star-formation region (MSFRs). We recently discovered the prototype frEGG in the Cygnus MSFR with HST. Further investigation using the Spitzer and Herschel archives have revealed a much larger number (>50) in Cygnus and other MSFRs. Our molecular-line observations of these show the presence of dense clouds with total masses of cool molecular gas exceeding 0.5 to a few Msun associated with these objects, thereby disproving the initial hypothesis based on their morphology that these have an origin similar to the proplyds (cometary-shaped photoevaporating protoplanetary disks) found in Orion. We report the results of our molecular-line studies and detailed high-resolution optical (with HST) or near-IR (with AO at the Keck Observatory) imaging of a few frEGGs in Cygnus, Carina and the W5 MSFRs. The images show the presence of young stars with associated outflow cavities and/or jets in the heads of the tadpole-shaped frEGGs. These results support our hypothesis that frEGGs are density concentrations originating in giant molecular clouds, that, when subject to the compression by the strong winds and ionization from massive stars in these MSFRs, become active star-forming cores. In summary, by virtue of their distinct, isolated morphologies, frEGGs offer us a clean probe of triggered star formation on small scales in the vicinity of massive stars.

  11. Preservation of protein globules and peptidoglycan in the mineralized cell wall of nitrate-reducing, iron(II)-oxidizing bacteria: a cryo-electron microscopy study.

    Science.gov (United States)

    Miot, J; Maclellan, K; Benzerara, K; Boisset, N

    2011-11-01

    Iron-oxidizing bacteria are important actors of the geochemical cycle of iron in modern environments and may have played a key role all over Earth's history. However, in order to better assess that role on the modern and the past Earth, there is a need for better understanding the mechanisms of bacterial iron oxidation and for defining potential biosignatures to be looked for in the geologic record. In this study, we investigated experimentally and at the nanometre scale the mineralization of iron-oxidizing bacteria with a combination of synchrotron-based scanning transmission X-ray microscopy (STXM), scanning transmission electron microscopy (STEM) and cryo-transmission electron microscopy (cryo-TEM). We show that the use of cryo-TEM instead of conventional microscopy provides detailed information of the successive iron biomineralization stages in anaerobic nitrate-reducing iron-oxidizing bacteria. These results suggest the existence of preferential Fe-binding and Fe-oxidizing sites on the outer face of the plasma membrane leading to the nucleation and growth of Fe minerals within the periplasm of these cells that eventually become completely encrusted. In contrast, the septa of dividing cells remain nonmineralized. In addition, the use of cryo-TEM offers a detailed view of the exceptional preservation of protein globules and the peptidoglycan within the Fe-mineralized cell walls of these bacteria. These organic molecules and ultrastructural details might be protected from further degradation by entrapment in the mineral matrix down to the nanometre scale. This is discussed in the light of previous studies on the properties of Fe-organic interactions and more generally on the fossilization of mineral-organic assemblies. © 2011 Blackwell Publishing Ltd.

  12. Carbonate- and silicate-rich globules in the kimberlitic rocks of northwestern Tarim large igneous province, NW China: Evidence for carbonated mantle source

    Science.gov (United States)

    Cheng, Zhiguo; Zhang, Zhaochong; Santosh, M.; Hou, Tong; Zhang, Dongyang

    2014-12-01

    We report carbonate- and silicate-rich globules and andradite from the Wajilitage kimberlitic rocks in the northwestern Tarim large igneous province, NW China. The carbonate-rich globules vary in size from 1 to 3 mm, and most have ellipsoidal or round shape, and are composed of nearly pure calcite. The silicate-rich globules are elliptical to round in shape and are typically larger than the carbonate-rich globules ranging from 2 to several centimeters in diameter. They are characterized by clear reaction rims and contain several silicate minerals such as garnet, diopside and phlogopite. The silicate-rich globules, reported here for the first time, are suggested to be related to the origin of andradite within the kimberlitic rocks. Our results show that calcite in the carbonate-rich globules has a high XCa (>0.97) and is characterized by extremely high concentrations of the total rare earth elements (up to 1500 ppm), enrichment in Sr (8521-10,645 ppm) and LREE, and remarkable depletion in Nd, Ta, Zr, Hf and Ti. The calcite in the silicate-rich globules is geochemically similar to those in the carbonate-rich globules except the lower trace element contents. Garnet is dominantly andradite (And59.56-92.32Grs5.67-36.03Pyr0.36-4.61Spe0-0.33) and is enriched in light rare earth elements (LREEs) and relatively depleted in Rb, Ba, Th, Pb, Sr, Zr and Hf. Phlogopite in the silicate-rich globules has a high Mg# ranging from 0.93 to 0.97. The composition of the diopside is Wo45.82-51.39En39.81-49.09Fs0.88-0.95 with a high Mg# ranging from 0.88 to 0.95. Diopside in the silicate-rich globules has low total rare earth element (REE) contents (14-31 ppm) and shows middle REE- (Eu to Gd), slight light REE- and heavy REE-enrichment with elevated Zr, Hf and Sr contents and a negative Nb anomaly in the normalized diagram. The matrix of the kimberlitic rocks are silica undersaturated (27.92-29.31 wt.% SiO2) with low Al2O3 (4.51-5.15 wt.%) and high CaO (17.29-17.77 wt.%) contents. The

  13. Body measures and milk production, milk fat globules granulometry and milk fatty acid content in Cabannina cattle breed

    Directory of Open Access Journals (Sweden)

    Ricardo Communod

    2013-03-01

    Full Text Available Aim of the study was to achieve scientific information about body measures and milk production of Cabannina cattle, a local breed reared in northern Italy. Fourteen body measures and five morphologic indexes were recorded from 86 heads enrolled in the herd book. Low differences between males and females of the same age-class were shown. Body measures were generally greater than those reported in previous studies, probably due to recent crosses. With reference to milk production, 991 test-day records from 128 lactations of 59 cows were analysed. Average milk daily production was 8 kg/d in 1st lactation to 10.61 in 3rd (P<0.05; the parameters of the Wood equation draw atypical curves with the exception of curves from spring calving cows. Only 74.5% of lactations with an adjusted R2 >0.75 showed a standard curve, with low persistence (7.7%, high value of d at peak (103 d and peak production of 20.18 kg of milk. Moreover, 100 milk samples (40 to 220 d of lactation were submitted to a granulometric survey by laser scatter technique in order to evaluate the dimensions of fat globules; then milk fat was analyzed by gas chromatography, and desaturase indexes were determined. Cabannina cows showed small fat globules with high specific surface. Furthermore mean diameter of milk fat globules decreased during lactation then rose. Milk fat contained high levels of cis-MUFA, and high desaturase indexes. In conclusion, the low size of Cabannina cattle orients for a limited meat production. Instead milk production has a higher economic potential, aimed at cheese production and human nutrition.

  14. A mixture of milk and vegetable lipids in infant formula changes gut digestion, mucosal immunity and microbiota composition in neonatal piglets.

    Science.gov (United States)

    Le Huërou-Luron, Isabelle; Bouzerzour, Karima; Ferret-Bernard, Stéphanie; Ménard, Olivia; Le Normand, Laurence; Perrier, Cécile; Le Bourgot, Cindy; Jardin, Julien; Bourlieu, Claire; Carton, Thomas; Le Ruyet, Pascale; Cuinet, Isabelle; Bonhomme, Cécile; Dupont, Didier

    2018-03-01

    Although composition of infant formula has been significantly improved during the last decade, major differences with the composition and structure of breast milk still remain and might affect nutrient digestion and gut biology. We hypothesized that the incorporation of dairy fat in infant formulas could modify their physiological impacts by making their composition closer to that of human milk. The effect of milk fat and milk fat globule membrane (MFGM) fragments in infant formulas on gut digestion, mucosal immunity and microbiota composition was evaluated. Three formulas containing either (1) vegetable lipids stabilized only by proteins (V-P), (2) vegetable lipids stabilized by a mixture of proteins and MFGM fragments (V-M) and (3) a mixture of milk and vegetable lipids stabilized by a mixture of proteins and MFGM fragments (M-M) were automatically distributed to 42 newborn piglets until slaughter at postnatal day (PND) 7 or 28, and compared to a fourth group of sow's suckling piglets (SM) used as a breast-fed reference. At both PND, casein and β-lactoglobulin digestion was reduced in M-M proximal jejunum and ileum contents compared to V-P and V-M ones leading to more numerous β-Cn peptides in M-M contents. The IFNγ cytokine secretion of ConA-stimulated MLN cells from M-M piglets tended to be higher than in V-P ones at PND 7 and PND 28 and was closer to that of SM piglets. No dietary treatment effect was observed on IL-10 MLN cell secretion. Changes in faecal microbiota in M-M piglets resulted in an increase in Proteobacteria and Bacteroidetes and a decrease in Firmicutes phyla compared to V-P ones. M-M piglets showed higher abundances of Parabacteroides, Escherichia/Shigella and Klebsiella genus. The incorporation of both milk fat and MFGM fragments in infant formula modifies protein digestion, the dynamic of the immune system maturation and the faecal microbiota composition.

  15. A novel isolation strategy for obtaining crude membrane vesicles from bovine skim milk

    DEFF Research Database (Denmark)

    Blans, Kristine; Larsen, Lotte Bach; Wiking, Lars

    Bovine milks content of phospholipid membranes have largely been explored in the cream fraction, and known as the milk fat globule membrane that surrounds fat droplets. In skim milk, the population of phospholipid membranes is reported to constitute membrane vesicles with a soluble content known...... is observed all over the gradient. The variety of the membrane vesicles is currently being investigated further by several means. Summary/conclusion: A new procedure for easy and gentle isolation of bovine milk membrane vesicles encompassing ultracentrifugation and size-exclusion chromatography has been...... established. The resulting vesicle isolate exhibits the general membrane vesicle characteristics and provides an appropriate start material from which the variety of milk vesicles can be investigated...

  16. Observation of persistent α-helical content and discrete types of backbone disorder during a molten globule to ordered peptide transition via deep-UV resonance Raman spectroscopy.

    Science.gov (United States)

    Brown, Mia C; Mutter, Andrew; Koder, Ronald L; JiJi, Renee D; Cooley, Jason W

    2013-07-01

    The molten globule state can aide in the folding of a protein to a functional structure and is loosely defined as an increase in structural disorder with conservation of the ensemble secondary structure content. Simultaneous observation of persistent secondary structure content with increased disorder has remained experimentally problematic. As a consequence, modeling how the molten globule state remains stable and how it facilitates proper folding remains difficult due to a lack of amenable spectroscopic techniques to characterize this class of partially unfolded proteins. Previously, deep-UV resonance Raman (dUVRR) spectroscopy has proven useful in the resolution of global and local structural fluctuations in the secondary structure of proteins. In this work, dUVRR was employed to study the molten globule to ordered transition of a model four-helix bundle protein, HP7. Both the average ensemble secondary structure and types of local disorder were monitored, without perturbation of the solvent, pH, or temperature. The molten globule to ordered transition is induced by stepwise coordination of two heme molecules. Persistent dUVRR spectral features in the amide III region at 1295-1301 and 1335-1338 cm -1 confirm previous observations that HP7 remains predominantly helical in the molten globule versus the fully ordered state. Additionally, these spectra represent the first demonstration of conserved helical content in a molten globule protein. With successive heme binding significant losses are observed in the spectral intensity of the amide III 3 and S regions (1230-1260 and 1390 cm -1 , respectively), which are known to be sensitive to local disorder. These observations indicate that there is a decrease in the structural populations able to explore various extended conformations, with successive heme binding events. DUVRR spectra indicate that the first heme coordination between two helical segments diminishes exploration of more elongated backbone structural

  17. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...

  18. Conformations and membrane-driven self-organization of rodlike fd virus particles on freestanding lipid membranes.

    Science.gov (United States)

    Petrova, Anastasiia B; Herold, Christoph; Petrov, Eugene P

    2017-10-11

    Membrane-mediated interactions and aggregation of colloidal particles adsorbed to responsive elastic membranes are challenging problems relevant for understanding the microscopic organization and dynamics of biological membranes. We experimentally study the behavior of rodlike semiflexible fd virus particles electrostatically adsorbed to freestanding cationic lipid membranes and find that their behavior can be controlled by tuning the membrane charge and ionic strength of the surrounding medium. Three distinct interaction regimes of rodlike virus particles with responsive elastic membranes can be observed. (i) A weakly charged freestanding cationic lipid bilayer in a low ionic strength medium represents a gentle quasi-2D substrate preserving the integrity, structure, and mechanical properties of the membrane-bound semiflexible fd virus, which under these conditions is characterized by a monomer length of 884 ± 4 nm and a persistence length of 2.5 ± 0.2 μm, in perfect agreement with its properties in bulk media. (ii) An increase in the membrane charge leads to the membrane-driven collapse of fd virus particles on freestanding lipid bilayers and lipid nanotubes into compact globules. (iii) When the membrane charge is low, and the mutual electrostatic repulsion of membrane-bound virus particles is screened to a considerable degree, membrane-driven self-organization of membrane-bound fd virus particles into long linear tip-to-tip aggregates showing dynamic self-assembly/disassembly and quasi-semiflexible behavior takes place. These observations are in perfect agreement with the results of recent theoretical and simulation studies predicting that membrane-mediated interactions can control the behavior of colloidal particles adsorbed on responsive elastic membranes.

  19. Membrane fusion

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  20. Biobased Membrane

    NARCIS (Netherlands)

    Koenders, E.A.B.; Zlopasa, J.; Picken, S.J.

    2015-01-01

    The present invention is in the field of a composition for forming a bio-compatible membrane applicable to building material, such as concrete, cement, etc., to a meth od of applying said composition for forming a bio-compatible membrane, a biocompatible membrane, use of said membrane for various

  1. Study of the variables which influence the impregnation of globules, compressed tablets and tablet triturates used in homeopathy

    Directory of Open Access Journals (Sweden)

    Fernanda Santos de Souza

    2012-09-01

    Full Text Available Globules, compressed tablets and tablet triturates are solid dosage forms used in homeopathy. Divergences can be noted between the preparation techniques described in official compendiums as well as those applied in homeopathic pharmacies. The difficulty associated with standardization of the impregnation of these dosage forms occurs due to the lack of detail provided for the techniques in the literature, leaving it up to each pharmacy to decide on the exact method of preparation. The objective was to optimize the impregnation technique, through investigating the variables that influence the impregnation of globules, compressed tablets and tablet triturates, applying the statistical tool of factorial design. The independent variables were the dosage form, percentage and type of impregnation and drying temperature, and the dependent variables were the mass gain, disintegration time, friability and hardness. For the globules, the greatest mass gain was for 10% impregnation and drying at 20 ºC. For the tablet triturates and compressed tablets the greatest mass gain was for 15% impregnation and there was no difference between the results obtained using simple and triple impregnation or different drying temperatures. The results can contribute to improving the final product quality, besides aiding in the establishment of standardized techniques for the official compendiums.Glóbulos, comprimidos e tabletes são formas farmacêuticas sólidas utilizadas em homeopatia. Constatam-se divergências entre técnicas de preparação descritas nos compêndios oficiais, bem como em farmácias homeopáticas. A dificuldade de padronização na impregnação destas formas farmacêuticas também ocorre devido à falta de detalhamento das técnicas na literatura existente, deixando para cada farmácia a escolha de como executá-las. O objetivo foi otimizar a técnica de impregnação, através do estudo de variáveis que interferem na impregnação de gl

  2. Determination of the physical parameters of Bok-globules by means of a stochastical radiative transfer method

    Science.gov (United States)

    Hengel, C.; Hegmann, M.; Röllig, M.; Kegel, W. H.

    During the last years, one of the key projects of the Astrophysics group at the University of Frankfurt was the theoretical examination of the influence of turbulence and density fluctuations on the formation of interstellar molecular lines, especially CO lines (Albrecht & Kegel 1987, Kegel et al. 1993, Piehler & Kegel 1995, Hegmann 1999). Based on an approach by G. Traving and collaborators (cf. Gail et al. 1974), a numerical code has been developed to deal with the NLTE problem in an isothermal spherical cloud being stabelized by turbulent and thermal pressure, considering the turbulent velocity field to be stochastic. Our model has been primarily constructed to achieve theoretical insight in the fundamental mechanisms of line formation under more realistic conditions. In view of the stage of development, the model has actually reached, we seriously think of it as an alternative tool for the evaluation of molecular lines emitted by molecular clouds, especially as the model assumptions are certainly closer to reality than the assumptions behind the standard evaluation methods such as e. g. LVG analysis. The objects the physics of which we believe to be closest to our model assumptions are starless Bok globules. We thus have performed observations at the HHT, where we have collected data of five Bok globules in the CO(2-1), CO(3-2), 13CO(2-1) and C18O(2-1) lines. In my contribution I will adress the question, if and how the physical parameters derived by our analysis of the observational data (central H2 density, temperature, correlation length of the turbulent velocity field, and mean square turbulent velocity) differ from the results of an LVG analysis (they do!) and what these findings imply from a physical point of view as well as from a critical viewpoint on the practice of data evaluation. I will talk about problems of our model at its current stage and possible consequences for an improvement of the model, and I will finally give an outlook, how, with

  3. Effect of temperature on the microstructure of fat globules and the immunoglobulin-mediated interactions between fat and bacteria in natural raw milk creaming.

    Science.gov (United States)

    D'Incecco, P; Ong, L; Pellegrino, L; Faoro, F; Barbiroli, A; Gras, S

    2018-02-02

    Natural creaming of raw milk is the first step in production of Grana Padano and Parmigiano Reggiano Protected Denomination of Origin cheeses. This process decreases the fat content and plays an important role in the removal of clostridia species that may cause late-blowing defects in ripened cheeses. Partial coalescence of fat globules-that may influence fat behavior in cheese making and affect the microstructure of fat in the final cheese product-was observed at creaming temperatures higher than 22°C by confocal laser scanning microscopy. The widespread practice of heating of milk at 37°C before creaming at 8°C resulted in important changes in the size distribution of fat globules in raw milk, potentially altering the ability of fat to entrap clostridia spores. We investigated the role of immunoglobulin classes in both the clustering of fat globules and the agglutination of Clostridium tyrobutyricum to fat globules during creaming. Immunogold labeling and transmission electron microscopy showed that IgA and IgM but not IgG were involved in both clustering and agglutination. Both vegetative cells and spores were clearly shown to agglutinate to fat droplets, a process that was suppressed by thermal denaturation of the immunoglobulins. The debacterization of raw milk through natural creaming was improved by the addition of purified immunoglobulins. Overall, these findings provide not only a better understanding of the phenomena occurring during the natural creaming but also practical insights into how the process of creaming may be optimized in cheese production plants. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  4. Effects of emulsifying components in the continuous phase of cream on the stability of fat globules and the physical properties of whipped cream.

    Science.gov (United States)

    Ihara, K; Hirota, M; Akitsu, T; Urakawa, K; Abe, T; Sumi, M; Okawa, T; Fujii, T

    2015-05-01

    The emulsifying components in cream are very important in controlling the physical characteristics of whipped cream. The effects of those components on the stability of fat globules and the physical characteristics of whipped cream were investigated. A low-molecular-weight emulsifier, and protein ingredients such as sodium caseinate and a casein partial hydrolysate (casein peptides), were used as emulsifying components in this investigation. The viscosity of deaerated whipped cream (called the serum viscosity) was measured to evaluate the degree of fat-globule aggregation. Furthermore, the shape-retention ability, which is the degree of reduction in the firmness of whipped cream between immediately after whipping and after 1d of refrigeration, was explored. The addition of the low-molecular-weight emulsifier in the continuous phase of dairy cream, which does not contain added low-molecular-weight emulsifiers, increased the stability of the fat globules and reduced the shape-retention ability of the whipped cream. The addition of protein ingredients (sodium caseinate and casein peptides) to the continuous phase of dairy cream had little effect. However, the addition of casein peptide in the continuous phase of dairy cream together with the low-molecular-weight emulsifier reduced the effect of the low-molecular-weight emulsifier on the stabilization of fat globules and the shape-retention ability of the whipped cream. The addition of casein peptide did not recover the serum viscosity; thus, other mechanisms might underlie this phenomenon. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  5. Hyaline globule-like structures in undifferentiated sarcoma cells of malignant müllerian mixed tumor of the fallopian tube.

    Science.gov (United States)

    Kuroda, Naoto; Inui, Yasunobu; Ohara, Masahiko; Hirouchi, Takashi; Mizuno, Keiko; Kubo, Ayumi; Hayashi, Yoshihiro; Enzan, Hideaki; Lee, Gang-Hong

    2007-03-01

    Malignant müllerian mixed tumors (MMMTs) of the fallopian tube are very rare neoplasms, and we present such a case with unusual findings here. A 57-year-old Japanese woman, after she received a medical checkup, underwent salpingo-oophorectomy on the suspicion of ovarian cancer. At the time of operation, the main tumor was present predominantly in the fallopian tube. Microscopically, the tumor consisted of carcinoma and sarcoma components. The carcinoma showed moderately to poorly differentiated adenocarcinoma. The sarcoma consisted of predominantly undifferentiated sarcoma and focally rhabdomyosarcomatous cells with abundant eosinophilic cytoplasm. Immunohistochemically, the differentiation toward rhabdomyosarcoma was confirmed. Interestingly, the cytoplasm of undifferentiated sarcoma cells contained hyaline globule-like structures. These structures showed a positive reaction for PAS, and these structures were not digested by the diastase pretreatment. Ultrastructurally, hyaline globule-like structures corresponded to lysosomes. Finally, pathologists should keep in mind that undifferentiated sarcoma cells in MMMT of the fallopian tube may contain hyaline globule-like structures in the cytoplasm.

  6. Identification of ABCA1 and ABCG1 in milk fat globules and mammary cells - Implications for milk cholesterol secretion

    DEFF Research Database (Denmark)

    Mani, O; Körner, M; Ontsouka, C E

    2011-01-01

    to test whether 1) ABCA1 and ABCG1 protein expression and subcellular localization in mammary epithelial cells (MEC) change during the pregnancy-lactation cycle, and 2) these 2 proteins were present in milk fat globules (MFG). Expression and localization in MEC were investigated in bovine MG tissues......, was higher during the end of lactation (12.2 ± 0.24) and the DP (12.5 ± 0.22) as compared with during early lactation (10.2 ± 0.65). In contrast, no significant change in ABCG1 expression existed between the stages. Throughout the cycle, ABCA1 and ABCG1 were detected in the apical (41.9 ± 24.8 and 49.0 ± 4.......96% of cows, respectively), basal (56.2 ± 28.1 and 54.6 ± 7.78% of cows, respectively), or entire cytoplasm (56.8 ± 13.4 and 61.6 ± 14.4% of cows, respectively) of MEC, or showed combined localization. Unlike ABCG1, ABCA1 was absent at the apical aspect of MEC during early lactation. Immunolabeling...

  7. On the effect of sodium salts on the coil-to-globule transition of poly(N-isopropylacrylamide).

    Science.gov (United States)

    Pica, Andrea; Graziano, Giuseppe

    2015-11-07

    It has been shown that sodium salts significantly affect the temperature of the coil-to-globule collapse transition of poly(N-isopropylacrylamide) [J. Am. Chem. Soc., 2005, 127, 14505]. Since this phenomenon resembles the cold renaturation of globular proteins, it can be studied by means of the theoretical approach devised to rationalise the occurrence and the mechanism of cold denaturation [G. Graziano, Phys. Chem. Chem. Phys., 2010, 12, 14245; Phys. Chem. Chem. Phys., 2014, 16, 21755]. It emerges that the collapse transition is driven by the decrease in the solvent-excluded volume in order to maximise the translational entropy of water molecules and ions. At a given temperature, the aqueous solutions of sodium salts have densities higher than that of water. For this reason, the magnitude of the solvent-excluded volume effect proves to be larger, stabilizing the globular conformations of poly(N-isopropylacrylamide). On the other hand, two large ions, iodide and thiocyanate, are poorly hydrated and stabilise the coil conformations of the polymer by a preferential binding mechanism.

  8. Effect of feeding camphor (Eucalyptus Globules) levels on some immunity characteristics, growth and gut microflora of japanese quails

    International Nuclear Information System (INIS)

    Abu Taleb, A.M.; Salah, H.M.; Ezzat, I.E.; El Barkouky, E.

    2003-01-01

    This experiment was conducted to evaluate the effect of adding Eucalyptus globules Egypt to Japanese quail diet on performance and some metabolic functions and immunity. Four hundred,one day old, unsexed japanese quails were used in this study. Quails were divided equally into four groups containing 100 birds in each. Each group contained 4 replicates of 25 birds. Group one was supplemented with 1% Egypt in basal diet, group two was supplemented with 2% Egypt in basal diet, group three was used as negative control (-ve)without any addition of antibiotic in diet or water, while group four represented the positive control (+ ve) by addition antibiotics (0.5 g neomycin sulphate +0.5 g oxytetracyclin) in drinking water for 5 days post hatching. The experimented diet contained 3200 Kcal ME/kg and 24% crude proteins. The end of the experiment was terminated when birds were 6 weeks old. Body weight, mortality, some organs weighs and some blood parameters were measured and some microbial population of small intestines was counted. Results indicated that the addition of Egypt led to significant increase in quails body weights, spleen, bursa and ovary and the measures of total proteins, globulins, haemagglutination inhibition (HI)and triiodothyronine (T3). Decrease in mortality ratio and less counts of microflora and salmonella of gut were also achieved as a result of diet camphor addition

  9. Dust evolution, a global view: III. Core/mantle grains, organic nano-globules, comets and surface chemistry.

    Science.gov (United States)

    Jones, A P

    2016-12-01

    Within the framework of The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS), this work explores the surface processes and chemistry relating to core/mantle interstellar and cometary grain structures and their influence on the nature of these fascinating particles. It appears that a realistic consideration of the nature and chemical reactivity of interstellar grain surfaces could self-consistently and within a coherent framework explain: the anomalous oxygen depletion, the nature of the CO dark gas, the formation of 'polar ice' mantles, the red wing on the 3 μm water ice band, the basis for the O-rich chemistry observed in hot cores, the origin of organic nano-globules and the 3.2 μm 'carbonyl' absorption band observed in comet reflectance spectra. It is proposed that the reaction of gas phase species with carbonaceous a-C(:H) grain surfaces in the interstellar medium, in particular the incorporation of atomic oxygen into grain surfaces in epoxide functional groups, is the key to explaining these observations. Thus, the chemistry of cosmic dust is much more intimately related with that of the interstellar gas than has previously been considered. The current models for interstellar gas and dust chemistry will therefore most likely need to be fundamentally modified to include these new grain surface processes.

  10. Membranous nephropathy

    Science.gov (United States)

    ... check for hepatitis B, hepatitis C, and syphilis Complement levels Cryoglobulin test Treatment The goal of treatment ... not as helpful for people with membranous nephropathy. Medicines used treat membranous nephropathy include: Angiotensin-converting enzyme ( ...

  11. Membrane Biophysics

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2013-01-01

    Physics, mathematics and chemistry all play a vital role in understanding the true nature and functioning of biological membranes, key elements of living processes. Besides simple spectroscopic observations and electrical measurements of membranes we address in this book the phenomena of coexistence and independent existence of different membrane components using various theoretical approaches. This treatment will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of processes inside membranes, and will thus eventually open new doors for high-level pharmaceutical approaches towards fighting membrane- and cell-related diseases.

  12. Site-specific hydration dynamics in the nonpolar core of a molten globule by dynamic nuclear polarization of water.

    Science.gov (United States)

    Armstrong, Brandon D; Choi, Jennifer; López, Carlos; Wesener, Darryl A; Hubbell, Wayne; Cavagnero, Silvia; Han, Songi

    2011-04-20

    Water-protein interactions play a direct role in protein folding. The chain collapse that accompanies protein folding involves extrusion of water from the nonpolar core. For many proteins, including apomyoglobin (apoMb), hydrophobic interactions drive an initial collapse to an intermediate state before folding to the final structure. However, the debate continues as to whether the core of the collapsed intermediate state is hydrated and, if so, what the dynamic nature of this water is. A key challenge is that protein hydration dynamics is significantly heterogeneous, yet suitable experimental techniques for measuring hydration dynamics with site-specificity are lacking. Here, we introduce Overhauser dynamic nuclear polarization at 0.35 T via site-specific nitroxide spin labels as a unique tool to probe internal and surface protein hydration dynamics with site-specific resolution in the molten globular, native, and unfolded protein states. The (1)H NMR signal enhancement of water carries information about the local dynamics of the solvent within ∼10 Å of a spin label. EPR is used synergistically to gain insights on local polarity and mobility of the spin-labeled protein. Several buried and solvent-exposed sites of apoMb are examined, each bearing a covalently bound nitroxide spin label. We find that the nonpoloar core of the apoMb molten globule is hydrated with water bearing significant translational dynamics, only 4-6-fold slower than that of bulk water. The hydration dynamics of the native state is heterogeneous, while the acid-unfolded state bears fast-diffusing hydration water. This study provides a high-resolution glimpse at the folding-dependent nature of protein hydration dynamics.

  13. Thermal properties of milk fat, xanthine oxidase, caseins and whey proteins in pulsed electric field-treated bovine whole milk.

    Science.gov (United States)

    Sharma, Pankaj; Oey, Indrawati; Everett, David W

    2016-09-15

    Thermodynamics of milk components (milk fat, xanthine oxidase, caseins and whey proteins) in pulsed electric field (PEF)-treated milk were compared with thermally treated milk (63 °C for 30 min and 73 °C for 15s). PEF treatments were applied at 20 or 26 kV cm(-1) for 34 μs with or without pre-heating of milk (55 °C for 24s), using bipolar square wave pulses in a continuous mode of operation. PEF treatments did not affect the final temperatures of fat melting (Tmelting) or xanthine oxidase denaturation (Tdenaturation), whereas thermal treatments increased both the Tmelting of milk fat and the Tdenaturation for xanthine oxidase by 2-3 °C. Xanthine oxidase denaturation was ∼13% less after PEF treatments compared with the thermal treatments. The enthalpy change (ΔH of denaturation) of whey proteins decreased in the treated-milk, and denaturation increased with the treatment intensity. New endothermic peaks in the calorimetric thermograms of treated milk revealed the formation of complexes due to interactions between MFGM (milk fat globule membrane) proteins and skim milk proteins. Evidence for the adsorption of complexes onto the MFGM surface was obtained from the increase in surface hydrophobicity of proteins, revealing the presence of unfolded hydrophobic regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Antirotaviral Activity of Bovine and Ovine Dairy Byproducts.

    Science.gov (United States)

    Parrón, José Antonio; Ripollés, Daniel; Pérez, María Dolores; Calvo, Miguel; Rasmussen, Jan Trige; Sánchez, Lourdes

    2017-05-31

    Rotaviral gastroenteritis is associated with significant morbidity in developed countries and a high rate of infant mortality in developing countries. Diverse studies have demonstrated that a wide range of milk-derived fractions exhibit antirotaviral activity. The present study shows the antirotaviral activity of some bovine and ovine dairy byproducts, buttermilk, butter serum, and milk fat globule membrane (MFGM), and evaluates the effect of cream washing and heat treatment on that activity. Furthermore, the rotavirus-neutralizing activity was evaluated for some MFGM proteins, such as xanthine oxidase and lactophorin. Ovine and bovine buttermilk reached rotavirus-neutralizing values of 51.3 and 32.2%, at 1 mg/mL, respectively. The cream washing process led to a significant decrease in the antirotaviral activity of fractions. This activity was also influenced by heat treatment. Treatment at 75 °C for 20 s caused 24.6 and 36.1% decreases of activity in bovine and ovine buttermilk, respectively, and 85 °C for 10 min caused decreases of 80.9 and 79.0% in both fractions, respectively.

  15. Thermodynamic analysis of ANS binding to partially unfolded α-lactalbumin: correlation of endothermic to exothermic changeover with formation of authentic molten globules.

    Science.gov (United States)

    Kim, Ki Hyung; Yun, Soi; Mok, K H; Lee, E K

    2016-09-01

    A fluorescent reporter, 8-anilino-1-naphthalene sulfonic acid (ANS), can serve as a reference molecule for conformational transition of a protein because its aromatic carbons have strong affinity with hydrophobic cores of partially unfolded molten globules. Using a typical calcium-binding protein, bovine α-lactalbumin (BLA), as a model protein, we compared the ANS binding thermodynamics to the decalcified (10 mM EDTA treated) apo-BLA at two representative temperatures: 20 and 40 °C. This is because the authentic molten globule is known to form more heavily at an elevated temperature such as 40 °C. Isothermal titration calorimetry experiments revealed that the BLA-ANS interactions at both temperatures were entropy-driven, and the dissociation constants were similar on the order of 10(-4)  M, but there was a dramatic changeover in the binding thermodynamics from endothermic at 20 °C to exothermic at 40 °C. We believe that the higher subpopulation of authentic molten globules at 40 °C than 20 °C would be responsible for the results, which also indicate that weak binding is sufficient to alter the ANS binding mechanisms. We expect that the thermodynamic properties obtained from this study would serve as a useful reference for investigating the binding of other hydrophobic ligands such as oleic acid to apo-BLA, because oleic acid is known to have tumor-selective cytotoxicity when complexed with partially unfolded α-lactalbumin. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Effect of Lenient Steam Injection (LSI) heat treatment of bovine milk on the activities of some enzymes, the milk fat globule and pH

    DEFF Research Database (Denmark)

    Dickow, Jonatan A.; Nielsen, Martin Thorup; Hammershøj, Marianne

    2012-01-01

    This study investigated the effects of Lenient Steam Injection (LSI) treatment at temperatures 70–150 C on the enzymatic activities of the indigenous milk enzymes alkaline phosphatase, lactoperoxidase (LPO), xanthine oxidase (XO), lipoprotein lipase (LPL) and plasmin in comparison with two...... reference heat treatments of 63 C for 30 s and of 72 C for 15 s by indirect heating. Milk fat globule (MFG) size distributions and pH were also monitored. Alkaline phosphatase, LPO, XO and LPL activities decreased with increasing LSI temperature. Plasmin activity was increased at temperatures

  17. Membrane paradigm

    International Nuclear Information System (INIS)

    Price, R.H.; Thorne, K.S.

    1986-01-01

    The membrane paradigm is a modified frozen star approach to modeling black holes, with particles and fields assuming a complex, static, boundary-layer type structure (membrane) near the event horizon. The membrane has no effects on the present or future evolution of particles and fields above itself. The mathematical representation is a combination of a formalism containing terms for the shear and bulk viscosity, surface pressure, momentum, temperature, entropy, etc., of the horizon and the 3+1 formalism. The latter model considers a family of three-dimensional spacelike hypersurfaces in one-dimensional time. The membrane model considers a magnetic field threading the hole and undergoing torque from the hole rotation. The field is cleaned by the horizon and distributed over the horizon so that ohmic dissipation is minimized. The membrane paradigm is invalid inside the horizon, but is useful for theoretically probing the properties of slowly evolving black holes

  18. Membrane processes

    Science.gov (United States)

    Staszak, Katarzyna

    2017-11-01

    The membrane processes have played important role in the industrial separation process. These technologies can be found in all industrial areas such as food, beverages, metallurgy, pulp and paper, textile, pharmaceutical, automotive, biotechnology and chemical industry, as well as in water treatment for domestic and industrial application. Although these processes are known since twentieth century, there are still many studies that focus on the testing of new membranes' materials and determining of conditions for optimal selectivity, i. e. the optimum transmembrane pressure (TMP) or permeate flux to minimize fouling. Moreover the researchers proposed some calculation methods to predict the membrane processes properties. In this article, the laboratory scale experiments of membrane separation techniques, as well their validation by calculation methods are presented. Because membrane is the "heart" of the process, experimental and computational methods for its characterization are also described.

  19. Heterogeneity of equilibrium molten globule state of cytochrome c induced by weak salt denaturants under physiological condition.

    Directory of Open Access Journals (Sweden)

    Hamidur Rahaman

    Full Text Available While many proteins are recognized to undergo folding via intermediate(s, the heterogeneity of equilibrium folding intermediate(s along the folding pathway is less understood. In our present study, FTIR spectroscopy, far- and near-UV circular dichroism (CD, ANS and tryptophan fluorescence, near IR absorbance spectroscopy and dynamic light scattering (DLS were used to study the structural and thermodynamic characteristics of the native (N, denatured (D and intermediate state (X of goat cytochorme c (cyt-c induced by weak salt denaturants (LiBr, LiCl and LiClO4 at pH 6.0 and 25°C. The LiBr-induced denaturation of cyt-c measured by Soret absorption (Δε400 and CD ([θ]409, is a three-step process, N ↔ X ↔ D. It is observed that the X state obtained along the denaturation pathway of cyt-c possesses common structural and thermodynamic characteristics of the molten globule (MG state. The MG state of cyt-c induced by LiBr is compared for its structural and thermodynamic parameters with those found in other solvent conditions such as LiCl, LiClO4 and acidic pH. Our observations suggest: (1 that the LiBr-induced MG state of cyt-c retains the native Met80-Fe(III axial bond and Trp59-propionate interactions; (2 that LiBr-induced MG state of cyt-c is more compact retaining the hydrophobic interactions in comparison to the MG states induced by LiCl, LiClO4 and 0.5 M NaCl at pH 2.0; and (3 that there exists heterogeneity of equilibrium intermediates along the unfolding pathway of cyt-c as highly ordered (X1, classical (X2 and disordered (X3, i.e., D ↔ X3 ↔ X2 ↔ X1 ↔ N.

  20. Milk fat globule-epidermal growth factor-factor VIII attenuates sepsis-induced acute kidney injury.

    Science.gov (United States)

    Cen, Cindy; Aziz, Monowar; Yang, Weng-Lang; Zhou, Mian; Nicastro, Jeffrey M; Coppa, Gene F; Wang, Ping

    2017-06-01

    Acute kidney injury (AKI) is most commonly caused by sepsis in critically ill patients, and it is associated with high morbidity and mortality. The pathophysiology of sepsis-induced AKI is generally accepted to include direct inflammatory injury, endothelial cell dysfunction, and apoptosis. Milk fat globule-epidermal growth factor-factor VIII (MFG-E8) is a secretory glycoprotein with a known role in the enhancement of apoptotic cell clearance and regulation of inflammation. We hypothesize that administration of recombinant mouse MFG-E8 (rmMFG-E8) can protect mice from kidney injuries caused by sepsis. Sepsis was induced in 8-wk-old male C57BL/6 mice by cecal ligation and puncture (CLP). rmMFG-E8 or phosphate-buffered saline (vehicle) was injected intravenously at a dosage of 20 μg/kg body weight at time of CLP (n = 5-8 mice per group). After 20 h, serum and renal tissue were harvested for various analyses. The renal injury markers blood urea nitrogen (BUN) and creatinine were determined by enzymatic and chemical reactions, respectively. The gene expression analysis was carried out by real-time quantitative polymerase chain reaction. At 20 h after CLP, serum levels of BUN and creatinine were both significantly increased in the vehicle group compared with the sham group, whereas the mice treated with rmMFG-E8 had a significant reduction in BUN and creatinine levels by 28% and 24.1%, respectively (BUN: 197.7 ± 23.6 versus 142.3 ± 20.7 mg/dL; creatinine: 0.83 ± 0.12 versus 0.63 ± 0.06 mg/dL; P sepsis through inhibiting the production of proinflammatory cytokines and chemokine, as well as through the activation of endothelial cells. Thus, MFG-E8 may have a therapeutic potential for treating AKI induced by sepsis. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Primordial membranes

    DEFF Research Database (Denmark)

    Hanczyc, Martin M; Monnard, Pierre-Alain

    2017-01-01

    Cellular membranes, which are self-assembled bilayer structures mainly composed of lipids, proteins and conjugated polysaccharides, are the defining feature of cell physiology. It is likely that the complexity of contemporary cells was preceded by simpler chemical systems or protocells during...... the various evolutionary stages that led from inanimate to living matter. It is also likely that primitive membranes played a similar role in protocell 'physiology'. The composition of such ancestral membranes has been proposed as mixtures of single hydrocarbon chain amphiphiles, which are simpler versions...

  2. Functional Role of Milk Fat Globule-Epidermal Growth Factor VIII in Macrophage-Mediated Inflammatory Responses and Inflammatory/Autoimmune Diseases

    Directory of Open Access Journals (Sweden)

    Young-Su Yi

    2016-01-01

    Full Text Available Inflammation involves a series of complex biological processes mediated by innate immunity for host defense against pathogen infection. Chronic inflammation is considered to be one of the major causes of serious diseases, including a number of autoimmune/inflammatory diseases, cancers, cardiovascular diseases, and neurological diseases. Milk fat globule-epidermal growth factor 8 (MFG-E8 is a secreted protein found in vertebrates and was initially discovered as a critical component of the milk fat globule. Previously, a number of studies have reported that MFG-E8 contributes to various biological functions including the phagocytic removal of damaged and apoptotic cells from tissues, the induction of VEGF-mediated neovascularization, the maintenance of intestinal epithelial homeostasis, and the promotion of mucosal healing. Recently, emerging studies have reported that MFG-E8 plays a role in inflammatory responses and inflammatory/autoimmune diseases. This review describes the characteristics of MFG-E8-mediated signaling pathways, summarizes recent findings supporting the roles of MFG-E8 in inflammatory responses and inflammatory/autoimmune diseases, and discusses MFG-E8 targeting as a potential therapeutic strategy for the development of anti-inflammatory/autoimmune disease drugs.

  3. Non-equilibrium effects evidenced by vibrational spectra during the coil-to-globule transition in poly(N-isopropylacrylamide) subjected to an ultrafast heating-cooling cycle.

    Science.gov (United States)

    Deshmukh, Sanket A; Kamath, Ganesh; Suthar, Kamlesh J; Mancini, Derrick C; Sankaranarayanan, Subramanian K R S

    2014-03-14

    Molecular dynamics simulations in conjunction with finite element calculations are used to explore the conformational dynamics of a thermo-sensitive oligomer, namely poly(N-isopropylacrylamide) (PNIPAM), subjected to an ultra-fast heating-cooling cycle. Finite element (FE) calculations were used to predict the temperature profile resulting from laser-induced heating of the polymer-aqueous system. The heating rate (∼0.6 K ps(-1)) deduced from FE calculations was used to heat an aqueous solution of PNIPAM consisting of 30 monomeric units (30-mer) from 285 K to 315 K. Non-equilibrium effects arising from the ultra-fast heating-cooling cycle results in a hysteresis during the coil-to-globule transition. The corresponding atomic scale conformations were characterized by monitoring the changes in the vibrational spectra, which provided a reliable metric to study the coil-to-globule transition in PNIPAM and vice-versa across the LCST. The vibrational spectra of bonds involving atoms from the oligomer backbone and the various side-groups (amide I, amide II, and the isopropyl group of PNIPAM) of the oligomers were analyzed to study the conformational changes in the oligomer corresponding to the observed hysteresis. The differences in the vibrational spectra calculated at various temperatures during heating and cooling cycles were used to understand the coil-to-globule and globule-to-coil transitions in the PNIPAM oligomer and identify the changes in the relative interactions between various atoms in the backbone and in the side groups of the oligomer with water. The shifts in the computed vibrational spectral peaks and the changes in the intensity of peaks for the different regions of PNIPAM, seen across the LCST during the heating cycle, are in good agreement with previous experimental studies. The changes in the radius of gyration (Rg) and vibrational spectra for amide I and amide II regions of PNIPAM suggest a clear coil-to-globule transition at ∼301 K during the

  4. Characterization and in vitro properties of oral lactobacilli in breastfed infants

    Science.gov (United States)

    2013-01-01

    Background Lactobacillus species can contribute positively to general and oral health and are frequently acquired by breastfeeding in infancy. The present study aimed to identify oral lactobacilli in breast and formula-fed 4 month-old infants and to evaluate potential probiotic properties of the dominant Lactobacillus species detected. Saliva and oral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining the effect of a new infant formula on child growth and development. Saliva was cultured and Lactobacillus isolates were identified from 16S rRNA gene sequences. Five L. gasseri isolates that differed in 16S rRNA sequence were tested for their ability to inhibit growth of selected oral bacteria and for adhesion to oral tissues. Oral swab samples were analyzed by qPCR for Lactobacillus gasseri. Results 43 (32.3%) infants were breastfed and 90 (67.7%) were formula-fed with either a standard formula (43 out of 90) or formula supplemented with a milk fat globule membrane (MFGM) fraction (47 out of 90). Lactobacilli were cultured from saliva of 34.1% breastfed infants, but only in 4.7% of the standard and 9.3% of the MFGM supplemented formula-fed infants. L. gasseri was the most prevalent (88% of Lactobacillus positive infants) of six Lactobacillus species detected. L. gasseri isolates inhibited Streptococcus mutans binding to saliva-coated hydroxyapatite, and inhibited growth of S. mutans, Streptococcus sobrinus, Actinomyces naeslundii, Actinomyces oris, Candida albicans and Fusobacterium nucleatum in a concentration dependent fashion. L. gasseri isolates bound to parotid and submandibular saliva, salivary gp340 and MUC7, and purified MFGM, and adhered to epithelial cells. L. gasseri was detected by qPCR in 29.7% of the oral swabs. Breastfed infants had significantly higher mean DNA levels of L. gasseri (2.14 pg/uL) than infants fed the standard (0.363 pg/uL) or MFGM (0.697 pg/uL) formula. Conclusions Lactobacilli

  5. Thermodynamic characterization of cytochrome c at low pH. Observation of the molten globule state and of the cold denaturation process.

    Science.gov (United States)

    Kuroda, Y; Kidokoro, S; Wada, A

    1992-02-20

    Several reports have pointed out the existence of intermediate states (both kinetic and equilibrium intermediate) between the native and the denatured states. The molten globule state, a compact intermediate state in which the secondary structure is formed but the tertiary structure fluctuates considerably, is currently being studied intensively because of its possible implication in the folding process of several proteins. We have examined the thermal stability of horse cytochrome c at low pH between 2.0 and 3.2 and different potassium chloride concentrations by absorbance of the Soret band, far and near-ultraviolet circular dichroism (u.v. c.d.) and tryptophan fluorescence using a multidimensional spectrophotometer. The concentration of potassium chloride ranged from 0 M to 0.5 M. The experimental thermal denaturation curves show that: (1) the helical content of cytochrome c remains stable at higher temperature when the concentration of salt is increased; whereas (2) the extent of ordering of the tertiary structure is weakly dependent on salt concentration; and (3) for cytochrome c, the stabilization of the molten globule state is induced by the binding of anions. Other salts such as NaCl, LiCl, potassium ferricyanide (K3Fe(CN)6) and Na2SO4 may also be used to stabilize the molten globule state. The thermodynamic analysis of the denaturation curves of c.d. at 222 nm and c.d. at 282 nm shows that, whereas a two-state (native and denatured) transition is observed at low-salt concentration, the far and near-u.v. c.d. melting curves of cytochrome c do not coincide with each other at high-salt concentration, and a minimum of three different thermodynamic states (IIb, intermediate or IIc, and denatured) is necessary to achieve a sufficient analysis. The intermediate state (called IIc) is attributed to the molten globule state because of its high secondary structure content and the absence of tertiary structure. Therefore, at low pH, cytochrome c is present in at least

  6. Identification and characterization of molten globule-like state of hen egg-white lysozyme in presence of salts under alkaline conditions.

    Science.gov (United States)

    Ansari, M A; Zubair, S; Atif, S M; Kashif, M; Khan, N; Rehan, M; Anwar, T; Iqbal, A; Owais, M

    2010-01-01

    In the present study, we elucidated the effect of potassium salts on alkali denatured hen egg white lysozyme (EC 3.2.1.17) using intrinsic/extrinsic fluorescence as well circular dichroism (CD) spectroscopic methods. Intrinsic fluorescence studies revealed that various potassium salts mediate stabilization of lysozyme against alkali denaturation. Far and near UV CD spectrum studies, showed that 2M KCl induced appreciable amount of secondary structure with minimum tertiary contacts in lysozyme at pH 12.6. Acrylamide quenching studies suggest that at pH 12.6, the presence of 2M KCl causes reduced accessibility of the quencher to tryptophan residues of the protein presumably because of its compact conformation. In summary, the results of present study suggest that lysozyme attains a compact folded intermediate with molten globule like characteristics at alkaline pH in presence of potassium chloride.

  7. Robotic membranes

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette

    2008-01-01

    , Vivisection and Strange Metabolisms, were developed at the Centre for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts in Copenhagen as a means of engaging intangible digital data with tactile physical material. As robotic membranes, they are a dual examination...

  8. trans-C18:1 isomers in cheeses enriched in unsaturated fatty acids and manufactured with different milk fat globule sizes.

    Science.gov (United States)

    Briard-Bion, Valerie; Juaneda, Pierre; Richoux, Romain; Guichard, Elisabeth; Lopez, Christelle

    2008-10-22

    Increasing the knowledge on dietary fat composition, mainly the minor components, will improve the nutritional value of foods and their labeling. In this study, we examined the trans-octadecenoic acid (C18:1) composition of Emmental cheeses enriched in unsaturated fatty acids (FA) and manufactured with milks produced by cows selected to produce small and large fat globules. The FA composition of the milks was not significantly ( P > 0.05) different from the FA composition of the corresponding Emmental cheeses. Increasing the unsaturated FA content of the cheeses using dietary manipulations lead to an increase in the trans-C18:1 and changed their isomeric profiles. In milk fat produced with the linseed-enriched diet, the trans-10 C18:1 concentration was greater than trans-11 C18:1 (vaccenic acid), which is classically the major trans-C18:1 in milk fat. The content in trans-C18:1 and more particularly in trans-10 C18:1 was negatively correlated with the size of fat globules ( r (2) = 0. 82 and 0.87, respectively) and related to milk fat depression. The trans-C18:1 content was negatively correlated with the saturated FA (slope = -0.35; r (2) = 0.81) and positively correlated with the unsaturated (slope = 0.29; r (2) = 0.85) and monounsaturated (slope = 0.32; r (2) = 0.81) FA. Focusing on the health-related considerations of fat in food products, further nutritional studies are needed to elucidate the role of trans-C18:1 isomers.

  9. REPRODUCTIVE PERFORMANCE OF DOMESTICATED BROODSTOCK OF SILVER PERCH, Bidyanus bidyanus (MITCHELL 1838 AND THE RELATIONSHIP BETWEEN OIL GLOBULE FRAGMENTATION AND EGG QUALITY

    Directory of Open Access Journals (Sweden)

    Sulaeman Sulaeman

    2017-12-01

    Full Text Available The experiments investigated the reproductive performance of the domesticated broodstock of the silver perch and the relationship between various degrees of oil globule fragmentation and egg quality. Six years old of second generation broodstock (n=3 were evaluated based on the fecundity, fertilisation rate, hatching rate, the degree of oil fragmentation of egg, and the quality of embryos and larvae produced. The fragmentation were grouped into three categories: un-fragmented (cat-1, moderately fragmented (cat-2, and highly fragmented (cat-3. The results showed that the broodstock had a relatively high fecundity (132,400 ± 7,22, fertilization rate (94.27 ± 1.28%, and hatching rates (87.94 ± 1.23%. The survival rate of larvae at 12 days post hatching (dph in cat-1 (71.3 ± 0.9% was higher than cat-2 (66.7 ± 0.9% whereas cat-2 was higher than cat-3 (61.3 ± 0.3%. The eggs was dominated by cat-1 (78.11 ± 2.44% which was significantly higher than cat-2 (21.26 ± 2.45% and cat-3 ones (0.40 ± 0.21%. The survival rate of embryo at 20 hours post spawning (hps and hatching rate of cat-1 (95.33 ± 0.00% and 93.33 ± 0.00% and cat-2 (90.00 ± 0.00% and 85.00 ± 0.00% were significantly higher than cat-3 (72.33 ± 1.76% and 60.33 ± 0.00%. The total length (TL of the larvae of cat-1 and cat-2 (8.44 ± 0.21 mm and 8.35 ± 0.23 mm respectively were significantly higher than larvae of cat-3 (7.09 ± 0.14 mm. No significant difference was found in the larval deformities among any categories. In conclusion, the reproductive performance of six year-old broodstock silver perch showing acceptable performance and egg categorisation based on oil globule fragmentation can be used as a useful tool to indicate eggs quality of silver perch.

  10. Milk Fat Globule-Epidermal Growth Factor-8 Pretreatment Attenuates Apoptosis and Inflammation via the Integrin-β3 Pathway after Surgical Brain Injury in Rats

    Directory of Open Access Journals (Sweden)

    Yicai Xiao

    2018-02-01

    Full Text Available Iatrogenic brain injury inevitably occurs in neurosurgical operations, leading to brain edema, ischemia, intracranial hematoma, and other postoperative complications, eventually worsening neurological outcomes of patients. If apoptotic cells are not rapidly eliminated by phagocytic engulfment, they may communicate with surrounding cells to undergo secondary necrosis and releasing toxic signals. Recent studies have shown that milk fat globule-epidermal growth factor-8 (MFGE8, which promotes phagocytosis and inhibits inflammation, is an endogenous protective factor in response to brain infarction, Alzheimer’s disease, subarachnoid hemorrhage, and prion disease. In the present study, we sought to investigate the different effects of both pretreated and posttreated recombinant milk fat globule-epidermal growth factor-8 (rhMFGE8 for the surgical brain injury (SBI rat model and potential involvement of its receptor integrin β3 for apoptosis and neuroinflammation after SBI. One hundred and sixty-seven male rats were employed in the preset study. Experiment 1 was performed to evaluate neurological scores and MFGE8, cleaved caspase-3 (CC3, and interleukine-1 beta (IL-1β levels at 3, 24, and 120 h after SBI. Experiment 2 was performed to evaluate the effects of rhMFGE8 pretreatment (10 min before SBI and rhMFGE8 posttreatment (6 h after SBI on brain edema at 24 and 72 h after SBI. Experiment 3 was performed to evaluate the potential anti-apoptotic and anti-inflammatory effects of rhMFGE8 pretreatment and posttreatment. Experiment 4 sought to investigate the involvement of the integrin-β3 signal in the effects of MFGE8 pretreatment. Our data showed rhMFGE8 pretreatment alleviated neurological deficits and decreased brain water content and apoptotic cells in the SBI model, which exhibited neurological dysfunction, apoptosis, and inflammation. Meanwhile, MFGE8 siRNA, which inhibited endogenous MFGE8 expression, significantly increased IL-1

  11. Molten Globule-Like Partially Folded State of Bacillus licheniformis α-Amylase at Low pH Induced by 1,1,1,3,3,3-Hexafluoroisopropanol

    Directory of Open Access Journals (Sweden)

    Adyani Azizah Abd Halim

    2014-01-01

    Full Text Available Effect of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP on acid-denatured Bacillus licheniformis α-amylase (BLA at pH 2.0 was investigated by far-UV CD, intrinsic fluorescence, and ANS fluorescence measurements. Addition of increasing HFIP concentrations led to an increase in the mean residue ellipticity at 222 nm (MRE222 nm up to 1.5 M HFIP concentration beyond which it sloped off. A small increase in the intrinsic fluorescence and a marked increase in the ANS fluorescence were also observed up to 0.4 M HFIP concentration, both of which decreased thereafter. Far- and near-UV CD spectra of the HFIP-induced state observed at 0.4 M HFIP showed significant retention of the secondary structures closer to native BLA but a disordered tertiary structure. Increase in the ANS fluorescence intensity was also observed with the HFIP-induced state, suggesting exposure of the hydrophobic clusters to the solvent. Furthermore, thermal denaturation of HFIP-induced state showed a non-cooperative transition. Taken together, all these results suggested that HFIP-induced state of BLA represented a molten globule-like state at pH 2.0.

  12. From biological membranes to biomimetic model membranes

    Directory of Open Access Journals (Sweden)

    Eeman, M.

    2010-01-01

    Full Text Available Biological membranes play an essential role in the cellular protection as well as in the control and the transport of nutrients. Many mechanisms such as molecular recognition, enzymatic catalysis, cellular adhesion and membrane fusion take place into the biological membranes. In 1972, Singer et al. provided a membrane model, called fluid mosaic model, in which each leaflet of the bilayer is formed by a homogeneous environment of lipids in a fluid state including globular assembling of proteins and glycoproteins. Since its conception in 1972, many developments were brought to this model in terms of composition and molecular organization. The main development of the fluid mosaic model was made by Simons et al. (1997 and Brown et al. (1997 who suggested that membrane lipids are organized into lateral microdomains (or lipid rafts with a specific composition and a molecular dynamic that are different to the composition and the dynamic of the surrounding liquid crystalline phase. The discovery of a phase separation in the plane of the membrane has induced an explosion in the research efforts related to the biology of cell membranes but also in the development of new technologies for the study of these biological systems. Due to the high complexity of biological membranes and in order to investigate the biological processes that occur on the membrane surface or within the membrane lipid bilayer, a large number of studies are performed using biomimicking model membranes. This paper aims at revisiting the fundamental properties of biological membranes in terms of membrane composition, membrane dynamic and molecular organization, as well as at describing the most common biomimicking models that are frequently used for investigating biological processes such as membrane fusion, membrane trafficking, pore formation as well as membrane interactions at a molecular level.

  13. Isolation and characterization of MUC15, a novel cell membrane-associated mucin

    DEFF Research Database (Denmark)

    Pallesen, Lone Tjener; Berglund, Lars; Rasmussen, Lone Kjær

    2002-01-01

    The present work reports isolation and characterization of a highly glycosylated protein from bovine milk fat globule membranes, known as PAS III. Partial amino-acid sequencing of the purified protein allowed construction of degenerate oligonucleotide primers, enabling isolation of a full-length c......DNA encoding a protein of 330 amino-acid residues. N-terminal amino-acid sequencing of derived peptides and the purified protein confirmed 76% of the sequence and demonstrated presence of a cleavable signal peptide of 23 residues, leaving a mature protein of 307 amino acids. Database searches showed...... no homology to any other proteins. A survey of the human genome indicated the presence of a corresponding gene on chromosome band 11p14.3. Isolation and sequencing of the complete cDNA sequence of the human homologue proved the existence of the gene product (334 amino-acid residues). This novel mucin...

  14. Molecular Interactions at Membranes

    DEFF Research Database (Denmark)

    Jagalski, Vivien

    Biological membranes are essential and complex structures in every living cell consisting of a fluid lipid bilayer sheet and membrane proteins. Its significance makes biological membranes not only interesting for medical research, but also has made it a target for toxins in the course of evolution....... Today, we know more than ever before about the properties of biological membranes. Advanced biophysical techniques and sophisticated membrane models allow us to answer specific questions about the structure of the components within membranes and their interactions. However, many detailed structural...... mechanisms of membrane compounds, including compounds associated with membranes, are still unknown due to the challenges that arise when probing the hydrophobic nature of the membrane's interior. For integral membrane proteins that span through the entire membrane, the amphiphilic environment is essential...

  15. PENGARUH KOMPOSOSI LAPISAN PADA PERMUKAAN GLOBULA MINYAK EMULSI SEBELUM PENGERINGAN SEMPROT TERHADAP SIFAT-SIFAT MIKROKAMSUL TRIGLISERIDA KAYA ASAM LEMAK W-3 [The Effect of the Composition of Adsorbed Layer at Globule Interface of -3 Fatty Acids Enriched Triglyceride Prior to Spray Drying on its Microcapsule Properties

    Directory of Open Access Journals (Sweden)

    Moch Adnan2

    2005-04-01

    Full Text Available Emulsification is the critical factor in microencapsulation by spray drying method. Sodium caseinate is a protein with good emulsifying properties. The properties could be improved by phospholipids addition in the emulsification. Phospholipids addition which stabilized oil globule might change the composition of adsorbed layer.This research was conducted to analyze the changes in composition at oil globule interface by analyzing emulsion systems of triglyceride enriched by -3 fatty acids at 5% (w/v stabilized by sodium caseinate (10% w/v and addition of phospholipids at 0; 0,5; 1,0; 1,5; 2,0; and 2,5% (w/v. The changes in composition of adsorbed layer could be determined from the changes in phospholipids and adsorbed protein concentrations at oil globule interface. Analyses were done to measure the possibility of casein-phospholipids complex, phospholipids and protein adsorption concentration at interface, and adsorbed protein.The increase of phospholipids concentration in the emulsions stabilized by sodium caseinate changed the composition of adsorbed layer at interface. There was phospholipids increase and adsorbed protein decrease at oil globule interface. These changes were caused by casein-phospholipids complex which that decreased surface activity and displacement protein by phospholipids that was adsorbed at oil globule interface.Changes of composition of casein-phospholipids at oil globule prior to microcapsulation process caused changes in the properties of microcapsule produced. The increasing phospholipids and decreasing casein concentrations at oil globule interface decreased the quality of the microcapsule, including decreasing in microencapsulation efficiency, in oxidative stability, and decreasing in EPA+DHA content.

  16. In-Depth Lipidomic Analysis of Molecular Species of Triacylglycerides, Diacylglycerides, Glycerophospholipids, and Sphingolipids of Buttermilk by GC-MS/FID, HPLC-ELSD, and UPLC-QToF-MS

    Directory of Open Access Journals (Sweden)

    Pilar Castro-Gómez

    2017-03-01

    Full Text Available Buttermilk, a byproduct of butter manufacturing, has gained considerable attention due to its high concentration of polar lipids as phospho- and sphingolipids from the milk fat globule membrane (MFGM. These polar lipids (PLs are essential components of all cellular membranes and exert a variety of indispensable metabolic, neurological, and intracellular signaling processes. Despite its importance, there are few research studies that report a comprehensive characterization of the lipid molecular species of MFGM that could contribute to a better understanding of their putative healthful activities. In this study, procedures such as pressurized liquid extraction of polar and nonpolar lipids and their fractionation by flash chromatography have been carried out. The obtained fractions were submitted to an exhaustive characterization from a lipidomic point of view. The characterization includes new data about the identification and quantification of triacylglycerides (TAG, diacylglycerides (DAG, and phospho- and sphingolipids using different chromatographic techniques. The fatty acid profile was comparable to that of the milk fat but with a highly diverse composition of fatty acids. Molecular species have also been determined by using ultra-high performance liquid chromatography/quadruple-time-of-flight mass spectrometry (UPLC/QToF-MS. The TAG (16:0/16:0/6:0 and TAG (16:0/16:0/8:0 were the predominant saturated TAG species and TAG (14:0/18:1/16:0 and TAG (16:0/16:0/18:1 presented the highest content of monounsaturated TAG species. Furthermore; over 30 molecular species of phosphatidylcholine (PC, phosphatidylethanolamine (PE, phosphatidylserine (PS, and phosphatidylinositol (PI could be identified within PL, with PC (16:0/18:1 being the most abundant species. Whereas C16:0 was found to be the preferred FA in TAGs, it was C18:1 in PLs. Several ganglioside species have also been characterized with d18:1 ceramide moiety and secondary acyl chains ranging

  17. In-Depth Lipidomic Analysis of Molecular Species of Triacylglycerides, Diacylglycerides, Glycerophospholipids, and Sphingolipids of Buttermilk by GC-MS/FID, HPLC-ELSD, and UPLC-QToF-MS

    Science.gov (United States)

    Castro-Gómez, Pilar; Montero, Olimpio; Fontecha, Javier

    2017-01-01

    Buttermilk, a byproduct of butter manufacturing, has gained considerable attention due to its high concentration of polar lipids as phospho- and sphingolipids from the milk fat globule membrane (MFGM). These polar lipids (PLs) are essential components of all cellular membranes and exert a variety of indispensable metabolic, neurological, and intracellular signaling processes. Despite its importance, there are few research studies that report a comprehensive characterization of the lipid molecular species of MFGM that could contribute to a better understanding of their putative healthful activities. In this study, procedures such as pressurized liquid extraction of polar and nonpolar lipids and their fractionation by flash chromatography have been carried out. The obtained fractions were submitted to an exhaustive characterization from a lipidomic point of view. The characterization includes new data about the identification and quantification of triacylglycerides (TAG), diacylglycerides (DAG), and phospho- and sphingolipids using different chromatographic techniques. The fatty acid profile was comparable to that of the milk fat but with a highly diverse composition of fatty acids. Molecular species have also been determined by using ultra-high performance liquid chromatography/quadruple-time-of-flight mass spectrometry (UPLC/QToF-MS). The TAG (16:0/16:0/6:0) and TAG (16:0/16:0/8:0) were the predominant saturated TAG species and TAG (14:0/18:1/16:0) and TAG (16:0/16:0/18:1) presented the highest content of monounsaturated TAG species. Furthermore; over 30 molecular species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylinositol (PI) could be identified within PL, with PC (16:0/18:1) being the most abundant species. Whereas C16:0 was found to be the preferred FA in TAGs, it was C18:1 in PLs. Several ganglioside species have also been characterized with d18:1 ceramide moiety and secondary acyl chains ranging from C

  18. Study of a novel agent for TCA precipitated proteins washing - comprehensive insights into the role of ethanol/HCl on molten globule state by multi-spectroscopic analyses.

    Science.gov (United States)

    Eddhif, Balkis; Lange, Justin; Guignard, Nadia; Batonneau, Yann; Clarhaut, Jonathan; Papot, Sébastien; Geffroy-Rodier, Claude; Poinot, Pauline

    2018-02-20

    Sample preparation for mass spectrometry-based proteomics is a key step for ensuring reliable data. In gel-free experimental workflows, protein purification often starts with a precipitation stage using trichloroacetic acid (TCA). In presence of TCA, proteins precipitate in a stable molten globule state making the pellet difficult to solubilize in aqueous buffer for proteolytic digestion and MS analysis. In this context, the objective of this work was to study the suitability of a novel agent, ethanol/HCl, for the washing of TCA-precipitated proteins. This method optimized the recovery of proteins in aqueous buffer (50 to 96%) while current organic solvents led to losses of material. Following a mechanistic study, the effect of ethanol/HCl on the conformation of TCA-precipitated proteins was investigated. It was shown that the reagent triggered the unfolding of TCA-stabilized molten globule into a reversible intermediate, characterized by a specific Raman signature, which favored protein subsequent resolubilization. Finally, the efficiency of ethanol/HCl for the washing of TCA-precipitated proteins extracted from a biofilm, a soil or a mouse liver was demonstrated (data available via ProteomeXchange with identifier PXD008110). Being versatile and simple, it could be of great interest to include an ethanol/HCl wash-step to produce high-quality protein extracts. In mass spectrometry-based proteomics workflows, proteins precipitation and/or washing usually involves the use of acetone. In fact, this solvent is effective for removing both biological interferences (e.g. lipids) and chemicals employed in protein extraction/purification protocols (e.g. TCA, SDS). However, the use of acetone can lead to significant protein losses. Moreover, when proteins are precipitated with TCA, the acetone-treated precipitate remains hard to disperse, leading to poor resolubilization of proteins in aqueous buffers. Here, we investigated the use of ethanol/HCl for washing TCA

  19. Magnetically controlled permeability membranes

    KAUST Repository

    Kosel, Jurgen

    2013-10-31

    A bioactive material delivery system can include a thermoresponsive polymer membrane and nanowires distributed within the thermoresponsive polymer membrane. Magnetic activation of a thermoresponsive polymer membrane can take place via altering the magnetization or dimensions of nanowires dispersed or ordered within the membrane matrix.

  20. Polymeric Membrane Reactors

    OpenAIRE

    José M. Sousa; Luís M. Madeira; João C. Santos; Adélio Mendes

    2008-01-01

    The aim of this chapter is the study of membrane reactors with polymeric membranes, particularly catalytic polymeric membranes. After an introduction where the main advantages and disadvantages of the use of polymeric membranes are summarised, a review of the main areas where they have been applied, integrated in chemical reactors, is presented. This excludes the field of bio-membranes processes, which is analysed in a specific chapter of this book. Particular attention is then given to model...

  1. Sheet Membrane Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

    2013-01-01

    A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

  2. Entraînement de globules d'huile par un tensio-actif. Etude de la formation du banc Mobilization of Oil Ganglia by a Surfactant Analysis of Bank Formation

    Directory of Open Access Journals (Sweden)

    Moulu J. C.

    2006-11-01

    Full Text Available Lors de l'injection d'une solution de tensio-actif dans un gisement déjà balayé par de l'eau, l'huile résiduelle, piégée sous la forme de globules discontinus, est remise en mouvement et se regroupe éventuellement sous la forme d'un banc d'huile. Le but de la présente étude est d'expliquer la formation de ce banc au cours d'un tel déplacement. Les résultats d'expériences réalisées en micromodèles de billes de verre permettent de constater que : - la récupération globale est corrélable avec le nombre capillaire Nc= uVdf/O, u et Vdf étant la viscosité et la vitesse de Darcy du fluide injecté, O la tension interfaciale avec l'huile en place ; - la vitesse des globules varie différemment avec u, Vdf, O et tend vers la même limite plus grande que la vitesse du fluide injecté pour de grandes valeurs du nombre capillaire Nc ; - le banc d'huile ne se forme que dans le cas où la vitesse des globules atteint celle du fluide injecté. L'huile déplacée reste alors groupée avec une saturation importante au niveau du front de tensio-actif. When a surfactant solution is injected into a reservoir previously waterflooded, the residual oil trapped as discontinuous ganglia is mobilized and eventually bunched together forming an oil bank. The aim of this study is to explain the formation of this bank during such a drive. The results of experiments performed in micromodels of glass beads show that: a Overall recovery can be correlated with the capillary number, Nc = uVfd/O, in which u and Vfd are the viscosity a and Darcy velocity of the injected fluid and O is the interfacial tension with the oil in place. b Ganglia velocity varies differently with u, Vfd and O, and it tends towards the same limit faster than the velocity of the injected fluid for high values of the capillary number Nc. c The oil bank is formed only in the case where globule velocity attaints that of injected fluid. the dispaced oil then remains bunched, with high

  3. Milk fat globule-epidermal growth factor-factor VIII-derived peptide MSP68 is a cytoskeletal immunomodulator of neutrophils that inhibits Rac1.

    Science.gov (United States)

    Hendricks, Louie; Aziz, Monowar; Yang, Weng-Lang; Nicastro, Jeffrey; Coppa, Gene F; Symons, Marc; Wang, Ping

    2017-02-01

    Prolonged neutrophil infiltration leads to exaggerated inflammation and tissue damage during sepsis. Neutrophil migration requires rearrangement of their cytoskeleton. Milk fat globule-epidermal growth factor-factor VIII-derived short peptide 68 (MSP68) has recently been shown to be beneficial in sepsis-induced tissue injury and mortality. We hypothesize that MSP68 inhibits neutrophil migration by modulating small GTPase Rac1-dependent cytoskeletal rearrangements. Bone marrow-derived neutrophils (BMDNs) or whole lung digest isolated neutrophils were isolated from 8 to 10 wk old C57BL/6 mice by Percoll density gradient centrifugation. The purity of BMDN was verified by flow cytometry with CD11b/Gr-1 staining. Neutrophils were stimulated with N-formylmethionine-leucine-phenylalanine (f-MLP) (10 nM) in the presence or absence of MSP68 at 10 nM or cecal ligation and puncture (CLP) was used to induce sepsis, and MSP68 was administered at 1 mg/kg intravenously. Cytoskeletal organization was assessed by phalloidin staining, followed by analysis using fluorescence microscopy. Activity of the Rac1 GTPase in f-MLP or CLP-activated BMDN in the presence or absence of MSP68 was assessed by GTPase enzyme-linked immunosorbent assay. Mitogen-activated protein (MAP) kinase activity was determined by western blot densitometry. BMDN treatment with f-MLP increased cytoskeletal remodeling as revealed by the localization of filamentous actin to the periphery of the neutrophil. By contrast, cells pretreated with MSP68 had considerably reduced filamentous actin polymerization. Cytoskeletal spreading is associated with the activation of the small GTPase Rac1. We found BMDN-treated with f-MLP or that were exposed to sepsis by CLP had increased Rac1 signaling, whereas the cells pretreated with MSP68 had significantly reduced Rac1 activation (P Rac1-MAP kinase-mediated neutrophil motility. Thus, MSP68 is a novel therapeutic candidate for regulating inflammation and tissue damage caused

  4. The roles of a novel anti-inflammatory factor, milk fat globule-epidermal growth factor 8, in patients with coronary atherosclerotic heart disease.

    Science.gov (United States)

    Dai, Wen; Li, Yan; Lv, Yong-nan; Wei, Chuan-dong; Zheng, Hong-yun

    2014-04-01

    Inflammation is now considered a main pathogenic factor in coronary atherosclerotic heart disease (CHD), and it has a positive correlation with plaque vulnerability. A novel anti-inflammatory factor, milk fat globule-epidermal growth factor 8 (MFG-E8), has been reported as having prominent anti-inflammatory effects in sepsis. However, few studies have reported on the association between MFG-E8 and CHD. In the present study, we aimed to investigate the serum MFG-E8 concentrations in patients with different stages of CHD or without CHD. Then, we studied the associations among MFG-E8, Gensini score, and high-sensitivity C-reactive protein (hs-CRP) in Chinese patients with CHD to illustrate the role of MFG-E8 in CHD. A total of 176 controls and 295 patients with CHD were selected for this study. To evaluate CHD severity, we calculated the Gensini score for all of the subjects. Serum levels of MFG-E8 were determined by an enzyme-linked immunosorbent assay (ELISA) kit; serum total cholesterol (TC), high density lipoprotein-cholesterol (HDL-c), low density lipoprotein-cholesterol (LDL-c), triglyceride (TG), and hs-CRP were detected by an automatic biochemistry analyzer; and fibrinogen (FIB) was analyzed with an automatic coagulation analyzer. Compared with the controls, the CHD group had a lower level of MFG-E8 (673.20±112.34 ng/mL vs. 134.89±4.74 ng/mL, p<0.001). The level of serum MFG-E8 in the acute myocardial infarction group (118.07±10.10 ng/mL) was significantly less than that in the stable angina group (p=0.025). Further analysis showed that MFG-E8 had a negative association with the Gensini score and the hs-CRP level (r=-0.590, p<0.001; r=-0.105, p=0.022, respectively). In addition, multiple regression analysis of the association between MFG-E8 and the main cardiovascular risk factors in our cases showed that MFG-E8 had a negative association with hs-CRP and a positive association with LDL-c (all p<0.05). The serum level of MFG-E8 was negatively associated with

  5. Synthetic Biological Membrane (SBM)

    Data.gov (United States)

    National Aeronautics and Space Administration — The ultimate goal of the Synthetic Biological Membrane project is to develop a new type of membrane that will enable the wastewater treatment system required on...

  6. Oxygen transport membrane

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  7. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  8. Premature rupture of membranes

    Science.gov (United States)

    ... gov/ency/patientinstructions/000512.htm Premature rupture of membranes To use the sharing features on this page, ... water that surrounds your baby in the womb. Membranes or layers of tissue hold in this fluid. ...

  9. Transmembrane Signalling: Membrane messengers

    Science.gov (United States)

    Cockroft, Scott L.

    2017-05-01

    Life has evolved elaborate means of communicating essential chemical information across cell membranes. Inspired by biology, two new artificial mechanisms have now been developed that use synthetic messenger molecules to relay chemical signals into or across lipid membranes.

  10. Extraction of uranium(VI) by emulsion liquid membrane containing 5,8-diethyl-7-hydroxy-6-dodecanone oxime

    International Nuclear Information System (INIS)

    Akiba, Kenichi; Takahashi, Toshihiko; Kanno, Takuji

    1984-01-01

    Extraction of uranium(VI) by a liquid surfactant membrane has been studied. The stability of water-in-oil (w/o) emulsion dispersed in the continuous aqueous phase increased with an increase in surfactant concentrations and in the fraction of the organic phase in emulsion globules. Uranium(VI) in dilute acid solutions was extracted into (w/o) emulsions containing 5,8-diethyl-7-hydroxy-6-dodecanone oxime (LIX 63) as a mobile carrier and its concentration decreased according to [U]sub(t)=[U]sub(o)exp(-ksub(obsd)t). The apparent rate constants (ksub(obsd)) increased with an increase in carrier concentrations and in external pH values, while they were slightly dependent on the stripping acid concentrations. Uranium was transported and concentrated into the internal aqueous droplets. The final concentration of uranium in the external aqueous phase dropped to about 10 -3 of its initial value. (author)

  11. A moving boundary problem and orthogonal collocation in solving a dynamic liquid surfactant membrane model including osmosis and breakage

    Directory of Open Access Journals (Sweden)

    E.C. Biscaia Junior

    2001-06-01

    Full Text Available A dynamic kinetic-diffusive model for the extraction of metallic ions from aqueous liquors using liquid surfactant membranes is proposed. The model incorporates undesirable intrinsic phenomena such as swelling and breakage of the emulsion globules that have to be controlled during process operation. These phenomena change the spatial location of the chemical reaction during the course of extraction, resulting in a transient moving boundary problem. The orthogonal collocation method was used to transform the partial differential equations into an ordinary differential equation set that was solved by an implicit numerical routine. The model was found to be numerically stable and reliable in predicting the behaviour of zinc extraction with acidic extractant for long residence times.

  12. Idiopathic epiretinal membrane

    NARCIS (Netherlands)

    Bu, Shao-Chong; Kuijer, Roelof; Li, Xiao-Rong; Hooymans, Johanna M M; Los, Leonoor I

    2014-01-01

    Background: Idiopathic epiretinal membrane (iERM) is a fibrocellular membrane that proliferates on the inner surface of the retina at the macular area. Membrane contraction is an important sight-threatening event and is due to fibrotic remodeling. Methods: Analysis of the current literature

  13. Model cell membranes

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Nylander, Tommy; Cardenas Gomez, Marite

    2014-01-01

    The high complexity of biological membranes has motivated the development and application of a wide range of model membrane systems to study biochemical and biophysical aspects of membranes in situ under well defined conditions. The aim is to provide fundamental understanding of processes control...

  14. Membrane contactor applications

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.

    2008-01-01

    In a membrane contactor the membrane separation is completely integrated with an extraction or absorption operation in order to exploit the benefits of both technologies fully. Membrane contactor applications that have been developed can be found in both water and gas treatment. Several recently

  15. On "spinning" membrane models

    NARCIS (Netherlands)

    Bergshoeff, E.; Sezgin, E.; Townsend, P.K.

    1988-01-01

    Several alternative actions for a bosonic membrane have recently been proposed. We show that a linearly realized locally world-volume-supersymmetric (spinning membrane) extension of any of these actions implies an analogous extension of the standard Dirac membrane action. We further show that a

  16. Meniscus Membranes For Separation

    Science.gov (United States)

    Dye, Robert C.; Jorgensen, Betty; Pesiri, David R.

    2005-09-20

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  17. Meniscus membranes for separations

    Science.gov (United States)

    Dye, Robert C [Irvine, CA; Jorgensen, Betty [Jemez Springs, NM; Pesiri, David R [Aliso Viejo, CA

    2004-01-27

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  18. Plasma membrane ATPases

    DEFF Research Database (Denmark)

    Palmgren, Michael Broberg; Bækgaard, Lone; Lopez Marques, Rosa Laura

    2011-01-01

    membrane include ABC transporters, vacuolar (V-type) H+ pumps, and P-type pumps. These pumps all utilize ATP as a fuel for energizing pumping. This review focuses on the physiological roles of plasma membrane P-type pumps, as they represent the major ATP hydrolytic activity in this membrane....

  19. Microporous silica membranes

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Yue, Yuanzheng

    2012-01-01

    Hydrothermal stability is a crucial factor for the application of microporous silica-based membranes in industrial processes. Indeed, it is well established that steam exposure may cause densification and defect formation in microporous silica membranes, which are detrimental to both membrane...... permeability and selectivity. Numerous previous studies show that microporous transition metal doped-silica membranes are hydrothermally more stable than pure silica membranes, but less permeable. Here we present a quantitative study on the impact of type and concentration of transition metal ions...... on the microporous structure, stability and permeability of amorphous silica-based membranes, providing information on how to design chemical compositions and synthetic paths for the fabrication of silica-based membranes with a well accessible and highly stabile microporous structure....

  20. Clustering on Membranes

    DEFF Research Database (Denmark)

    Johannes, Ludger; Pezeshkian, Weria; Ipsen, John H

    2018-01-01

    Clustering of extracellular ligands and proteins on the plasma membrane is required to perform specific cellular functions, such as signaling and endocytosis. Attractive forces that originate in perturbations of the membrane's physical properties contribute to this clustering, in addition to direct...... protein-protein interactions. However, these membrane-mediated forces have not all been equally considered, despite their importance. In this review, we describe how line tension, lipid depletion, and membrane curvature contribute to membrane-mediated clustering. Additional attractive forces that arise...... from protein-induced perturbation of a membrane's fluctuations are also described. This review aims to provide a survey of the current understanding of membrane-mediated clustering and how this supports precise biological functions....

  1. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become

  2. Supported ionic liquid membrane in membrane reactor

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Zunita, M.; Dharmawijaya, P. T.; Wenten, I. G.

    2017-01-01

    Membrane reactor is a device that integrates membrane based separation and (catalytic) chemical reaction vessel in a single device. Ionic liquids, considered to be a relatively recent magical chemical due to their unique properties, have a large variety of applications in all areas of chemical industries. Moreover, the ionic liquid can be used as membrane separation layer and/or catalytically active site. This paper will review utilization of ionic liquid in membrane reactor related applications especially Fischer-Tropsch, hydrogenation, and dehydrogenation reaction. This paper also reviews about the capability of ionic liquid in equilibrium reaction that produces CO2 product so that the reaction will move towards the product. Water gas shift reaction in ammonia production also direct Dimethyl Ether (DME) synthesis that produces CO2 product will be discussed. Based on a review of numerous articles on supported ionic liquid membrane (SILM) indicate that ionic liquids have the potential to support the process of chemical reaction and separation in a membrane reactor.

  3. Emulsification using microporous membranes

    Directory of Open Access Journals (Sweden)

    Goran T. Vladisavljević

    2011-10-01

    Full Text Available Membrane emulsification is a process of injecting a pure dispersed phase or pre-emulsion through a microporous membrane into the continuous phase. As a result of the immiscibility of the two phases, droplets of the dispersed phase are formed at the outlets of membrane pores. The droplets formed in the process are removed from the membrane surface by applying cross-flow or stirring of the continuous phase or using a dynamic (rotating or vibrating membrane. The most commonly used membrane for emulsification is the Shirasu Porous Glass (SPG membrane, fabricated through spinodal decomposition in a melt consisting of Japanese volcanic ash (Shirasu, boric acid and calcium carbonate. Microsieve membranes are increasingly popular as an alternative to highly tortuous glass and ceramic membranes. Microsieves are usually fabricated from nickel by photolithography and electroplating or they can be manufactured from silicon nitride via Reactive Ion Etching (RIE. An advantage of microsieves compared to the SPG membrane is in much higher transmembrane fluxes and higher tolerance to fouling by the emulsion ingredients due to the existence of short, straight through pores. Unlike conventional emulsification devices such as high-pressure valve homogenisers and rotor-stator devices, membrane emulsification devices permit a precise control over the mean pore size over a wide range and during the process insignificant amount of energy is dissipated as heat. The drop size is primarily determined by the pore size, but it depends also on other parameters, such as membrane wettability, emulsion formulation, shear stress on the membrane surface, transmembrane pressure, etc.

  4. Phospholipids in Milk Fat: Composition, Biological and Technological Significance, and Analytical Strategies

    Directory of Open Access Journals (Sweden)

    Giovanna Contarini

    2013-01-01

    Full Text Available Glycerophospholipids and sphingolipids are quantitatively the most important phospholipids (PLs in milk. They are located on the milk fat globule membrane (MFGM and in other membranous material of the skim milk phase. They include principally phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine, while sphingomyelin is the dominant species of sphingolipids There is considerable evidence that PLs have beneficial health effects, such as regulation of the inflammatory reactions, chemopreventive and chemotherapeutic activity on some types of cancer, and inhibition of the cholesterol absorption. PLs show good emulsifying properties and can be used as a delivery system for liposoluble constituents. Due to the amphiphilic characteristics of these molecules, their extraction, separation and detection are critical points in the analytical approach. The extraction by using chloroform and methanol, followed by the determination by high pressure liquid chromatography (HPLC, coupled with evaporative light scattering (ELSD or mass detector (MS, are the most applied procedures for the PL evaluation. More recently, nuclear magnetic resonance spectrometry (NMR was also used, but despite it demonstrating high sensitivity, it requires more studies to obtain accurate results. This review is focused on milk fat phospholipids; their composition, biological activity, technological properties, and significance in the structure of milk fat. Different analytical methodologies are also discussed.

  5. Ion-conducting membranes

    Energy Technology Data Exchange (ETDEWEB)

    Masel, Richard I.; Sajjad, Syed Dawar; Gao, Yan; Liu, Zengcai; Chen, Qingmei

    2017-12-26

    An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x. R.sub.s is a positively charged cyclic amine group. R.sub.x is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-R.sub.x groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.

  6. Gas separation with membranes

    International Nuclear Information System (INIS)

    Schulz, G.; Michele, H.; Werner, U.

    1982-01-01

    Gas separation with membranes has already been tested in numerous fields of application, e.g. uranium enrichment of H 2 separation. In many of these processes the mass transfer units, so-called permeators, have to be connected in tandem in order to achieve high concentrations. A most economical operating method provides for each case an optimization of the cascades with regard to the membrane materials, construction and design of module. By utilization of the concentration gradient along the membrane a new process development has been accomplished - the continuously operating membrane rectification unit. Investment and operating costs can be reduced considerably for a number of separating processes by combining a membrane rectification unit with a conventional recycling cascade. However, the new procedure requires that the specifications for the module construction, flow design, and membrane properties be reconsidered. (orig.) [de

  7. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  8. Polyarylether composition and membrane

    Science.gov (United States)

    Hung, Joyce; Brunelle, Daniel Joseph; Harmon, Marianne Elisabeth; Moore, David Roger; Stone, Joshua James; Zhou, Hongyi; Suriano, Joseph Anthony

    2010-11-09

    A composition including a polyarylether copolymer is provided. The copolymer includes a polyarylether backbone; and a sulfonated oligomeric group bonded to the polyarylether suitable for use as a cation conducting membrane. Method of bonding a sulfonated oligomeric group to the polyarylether backbone to form a polyarylether copolymer. The membrane may be formed from the polyarylether copolymer composition. The chain length of the sulfonated oligomeric group may be controlled to affect or control the ion conductivity of the membrane.

  9. Photoresponsive nanostructured membranes

    KAUST Repository

    Madhavan, Poornima

    2016-07-26

    The perspective of adding stimuli-response to isoporous membranes stimulates the development of separation devices with pores, which would open or close under control of environment chemical composition, temperature or exposure to light. Changes in pH and temperature have been previously investigated. In this work, we demonstrate for the first time the preparation of photoresponsive isoporous membranes, applying self-assembly non-solvent induced phase separation to a new light responsive block copolymer. First, we optimized the membrane formation by using poly(styrene-b-anthracene methyl methacrylate-b-methylmethacrylate) (PS-b-PAnMMA-b-PMMA) copolymer, identifying the most suitable solvent, copolymer block length, and other parameters. The obtained final triblock copolymer membrane morphologies were characterized using atomic force and electron microscopy. The microscopic analysis reveals that the PS-b-PAnMMA-b-PMMA copolymer can form both lamellar and ordered hexagonal nanoporous structures on the membrane top layer in appropriate solvent compositions. The nanostructured membrane emits fluorescence due to the presence of the anthracene mid-block. On irradiation of light the PS-b-PAnMMA-b-PMMA copolymer membranes has an additional stimuli response. The anthracene group undergoes conformational changes by forming [4 + 4] cycloadducts and this alters the membrane\\'s water flux and solute retention. © 2016 The Royal Society of Chemistry.

  10. Gas separation membranes

    Science.gov (United States)

    Schell, William J.

    1979-01-01

    A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

  11. Mixed reverse micelles facilitated downstream processing of lipase involving water-oil-water liquid emulsion membrane.

    Science.gov (United States)

    Bhowal, Saibal; Priyanka, B S; Rastogi, Navin K

    2014-01-01

    Our earlier work for the first time demonstrated that liquid emulsion membrane (LEM) containing reverse micelles could be successfully used for the downstream processing of lipase from Aspergillus niger. In the present work, we have attempted to increase the extraction and purification fold of lipase by using mixed reverse micelles (MRM) consisting of cationic and nonionic surfactants in LEM. It was basically prepared by addition of the internal aqueous phase solution to the organic phase followed by the redispersion of the emulsion in the feed phase containing enzyme, which resulted in globules of water-oil-water (WOW) emulsion for the extraction of lipase. The optimum conditions for maximum lipase recovery (100%) and purification fold (17.0-fold) were CTAB concentration 0.075 M, Tween 80 concentration 0.012 M, at stirring speed of 500 rpm, contact time 15 min, internal aqueous phase pH 7, feed pH 9, KCl concentration 1 M, NaCl concentration 0.1 M, and ratio of membrane emulsion to feed volume 1:1. Incorporation of the nonionic surfactant (e.g., Tween 80) resulted in remarkable improvement in the purification fold (3.1-17.0) of the lipase. LEM containing a mixture of nonionic and cationic surfactants can be successfully used for the enhancement in the activity recovery and purification fold during downstream processing of enzymes/proteins. © 2014 American Institute of Chemical Engineers.

  12. ETUDE DE L'EFFET DE QUELQUES FACTEURS SUR LA CYTOTOXICITE INDUITE PAR L'AMPHOTERICINE B ASSOCIEE AUX LIPOPROTEINES DU SERUM SANGUIN CHEZ DES CELLULES DE GLOBULES ROUGES HUMAINES

    OpenAIRE

    BOUCHERIT, ATMANI Zahia

    2014-01-01

    toxiques. Dans le cadre de l'élaboration d'une stratégie de développement de cette molécule visant à augmenter l'index thérapeutique tout en réduisant la toxicité, nous avons étudié l'effet de quelques facteurs sur la cytotoxicité induite par l'amphotéricine B associée à des lipoprotéines du sérum sanguin chez le globule rouge humain (modèle universel de cellules animales supérieures). Dans notre travail nous avons abordé d'une part, les effets des caractéristiques des lipoprot...

  13. Enantioseparation with liquid membranes

    NARCIS (Netherlands)

    Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo

    Chiral resolution of racemic products is a challenging and important task in the pharmaceutical, agrochemical, flavor, polymer and fragrances industries. One of the options for these challenging separations is to use liquid membranes. Although liquid membranes have been known for almost four decades

  14. Porous ceramic membranes

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Biesheuvel, Pieter Maarten

    2000-01-01

    Synthetic membranes are increasingly used for energy-efficient separation of liquid and gaseous mixtures in household applications, environmental technology and the chemical and energy industry. Besides, membranes are used in component-specific sensors in gas and liquid streams, preferably combined

  15. Polymide gas separation membranes

    Science.gov (United States)

    Ding, Yong; Bikson, Benjamin; Nelson, Joyce Katz

    2004-09-14

    Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas separation properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.

  16. Membrane module assembly

    Science.gov (United States)

    Kaschemekat, Jurgen

    1994-01-01

    A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

  17. Elastic membranes in confinement.

    Science.gov (United States)

    Bostwick, J B; Miksis, M J; Davis, S H

    2016-07-01

    An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and coiled DNA, have fine internal structure in which a membrane (or elastic member) is geometrically 'confined' by another object. Here, the two-dimensional shape of an elastic membrane in a 'confining' box is studied by introducing a repulsive confinement pressure that prevents the membrane from intersecting the wall. The stage is set by contrasting confined and unconfined solutions. Continuation methods are then used to compute response diagrams, from which we identify the particular membrane mechanics that generate mitochondria-like shapes. Large confinement pressures yield complex response diagrams with secondary bifurcations and multiple turning points where modal identities may change. Regions in parameter space where such behaviour occurs are then mapped. © 2016 The Author(s).

  18. Membrane projection lithography

    Energy Technology Data Exchange (ETDEWEB)

    Burckel, David Bruce; Davids, Paul S; Resnick, Paul J; Draper, Bruce L

    2015-03-17

    The various technologies presented herein relate to a three dimensional manufacturing technique for application with semiconductor technologies. A membrane layer can be formed over a cavity. An opening can be formed in the membrane such that the membrane can act as a mask layer to the underlying wall surfaces and bottom surface of the cavity. A beam to facilitate an operation comprising any of implantation, etching or deposition can be directed through the opening onto the underlying surface, with the opening acting as a mask to control the area of the underlying surfaces on which any of implantation occurs, material is removed, and/or material is deposited. The membrane can be removed, a new membrane placed over the cavity and a new opening formed to facilitate another implantation, etching, or deposition operation. By changing the direction of the beam different wall/bottom surfaces can be utilized to form a plurality of structures.

  19. Membrane technology and applications

    International Nuclear Information System (INIS)

    Khalil, F.H.

    1997-01-01

    The main purpose of this dissertation is to prepare and characterize some synthetic membranes obtained by radiation-induced graft copolymerization of and A Am unitary and binary system onto nylon-6 films. The optimum conditions at which the grafting process proceeded homogeneously were determined. Some selected properties of the prepared membranes were studied. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), x-ray diffraction (XRD), mechanical properties and U.V./vis, instruments and techniques were used to characterize the prepared membranes. The use of such membranes for the decontamination of radioactive waste and some heavy metal ions as water pollutants were investigated. These grafted membranes showed good cation exchange properties and may be of practical interest in waste water treatment whether this water was radioactive or not. 4 tabs., 68 figs., 146 refs

  20. Mechanical properties of milk sphingomyelin bilayer membranes in the gel phase: Effects of naturally complex heterogeneity, saturation and acyl chain length investigated on liposomes using AFM.

    Science.gov (United States)

    Et-Thakafy, Oumaima; Delorme, Nicolas; Guyomarc'h, Fanny; Lopez, Christelle

    2018-01-01

    Sphingomyelin (SM) molecules are major lipid components of plasma membranes that are involved in functional domains. Among natural SMs, that found in milk (milk-SM) exhibits important acyl chain heterogeneities in terms of length and saturation, which could affect the biophysical properties and biological functions of the milk fat globule membrane or of liposome carriers. In this study, the thermotropic and mechanical properties of milk-SM, synthetic C16:0-SM, C24:0-SM and the binary mixtures C16:0-SM/C24:0-SM (50:50% mol) and C24:0-SM/C24:1-SM (95:5% mol) bilayer membranes were investigated using differential scanning calorimetry and atomic force microscopy, respectively. Results showed that acyl chain length, heterogeneity and unsaturation affected i) the temperature of phase transition of SM bilayers, and ii) the mechanical properties of liposome (diametermembranes in the gel phase, e.g. the Young modulus E and the bending rigidity k C . This study increases our knowledge about the key role of naturally complex lipid compositions in tailoring the physical properties of biological membranes. It could be also used in liposomes development e.g. to select the suitable lipid composition according to usage. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. PERSISTENT PUPILLARY MEMBRANE OR ACCESSORY IRIS MEMBRANE?.

    Science.gov (United States)

    Gavriş, Monica; Horge, Ioan; Avram, Elena; Belicioiu, Roxana; Olteanu, Ioana Alexandra; Kedves, Hanga

    2015-01-01

    Frequently, in literature and curent practice, accessory iris membrane (AIM) and persistant pupillary membrane (PPM) are confused. Both AIM and PPM are congenital iris anomalies in which fine or thick iris strands arrise form the collarette and obscure the pupil. AIM, which is also called iris duplication, closely resembles the normal iris tissue in color and thickness and presents a virtual second pseudopupil aperture in the centre while PPM even in its extreme forms presents as a translucent or opaque membranous structure that extends across the pupil and has no pseudopupil. Mydriatiscs, laser treatment or surgery is used to clear the visual axis and optimize visual development. Surgical intervention is reserved for large, dense AIMs and PPMs. Our patient, a 29 year old male, has come with bilateral dense AIM, bilateral compound hyperopic astigmatism, BCVA OD = 0.6, BCVA OS = 0.4, IOP OU = 17 mmHg. To improve the visual acuity of the patient we decided to do a bilateral membranectomy, restoring in this way transparency of the visual axis. After surgery, the visual acuity improved to BCVA OD= 0.8, BCVA OS=0.8.

  2. Fuel cell membrane humidification

    Science.gov (United States)

    Wilson, Mahlon S.

    1999-01-01

    A polymer electrolyte membrane fuel cell assembly has an anode side and a cathode side separated by the membrane and generating electrical current by electrochemical reactions between a fuel gas and an oxidant. The anode side comprises a hydrophobic gas diffusion backing contacting one side of the membrane and having hydrophilic areas therein for providing liquid water directly to the one side of the membrane through the hydrophilic areas of the gas diffusion backing. In a preferred embodiment, the hydrophilic areas of the gas diffusion backing are formed by sewing a hydrophilic thread through the backing. Liquid water is distributed over the gas diffusion backing in distribution channels that are separate from the fuel distribution channels.

  3. Extracorporeal membrane oxygenation

    Science.gov (United States)

    Extracorporeal membrane oxygenation (ECMO) is a treatment that uses a pump to circulate blood through an artificial lung back into the bloodstream of a very ill baby. This system provides heart-lung bypass support ...

  4. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-02-01

    This factsheet describes a research project that will focus on the development and application of nonporous high gas flux perfluoro membranes with high temperature rating and excellent chemical resistance.

  5. Inverse colloidal crystal membranes for hydrophobic interaction membrane chromatography.

    Science.gov (United States)

    Vu, Anh T; Wang, Xinying; Wickramasinghe, S Ranil; Yu, Bing; Yuan, Hua; Cong, Hailin; Luo, Yongli; Tang, Jianguo

    2015-08-01

    Hydrophobic interaction membrane chromatography has gained interest due to its excellent performance in the purification of humanized monoclonal antibodies. The membrane material used in hydrophobic interaction membrane chromatography has typically been commercially available polyvinylidene fluoride. In this contribution, newly developed inverse colloidal crystal membranes that have uniform pores, high porosity and, therefore, high surface area for protein binding are used as hydrophobic interaction membrane chromatography membranes for humanized monoclonal antibody immunoglobulin G purification. The capacity of the inverse colloidal crystal membranes developed here is up to ten times greater than commercially available polyvinylidene fluoride membranes with a similar pore size. This work highlights the importance of developing uniform pore size high porosity membranes in order to maximize the capacity of hydrophobic interaction membrane chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Fabrication of electrospun nanofibrous membranes for membrane distillation application

    KAUST Repository

    Francis, Lijo

    2013-02-01

    Nanofibrous membranes of Matrimid have been successfully fabricated using an electrospinning technique under optimized conditions. Nanofibrous membranes are found to be highly hydrophobic with a high water contact angle of 130°. Field emission scanning electron microscopy and pore size distribution analysis revealed the big pore size structure of electrospun membranes to be greater than 2 μm and the pore size distribution is found to be narrow. Flat sheet Matrimid membranes were fabricated via casting followed by phase inversion. The morphology, pore size distribution, and water contact angle were measured and compared with the electrospun membranes. Both membranes fabricated by electrospinning and phase inversion techniques were tested in a direct contact membrane distillation process. Electrospun membranes showed high water vapor flux of 56 kg/m2-h, which is very high compared to the casted membrane as well as most of the fabricated and commercially available highly hydrophobic membranes. ©2013 Desalination Publications.

  7. Bacterial membrane proteomics.

    Science.gov (United States)

    Poetsch, Ansgar; Wolters, Dirk

    2008-10-01

    About one quarter to one third of all bacterial genes encode proteins of the inner or outer bacterial membrane. These proteins perform essential physiological functions, such as the import or export of metabolites, the homeostasis of metal ions, the extrusion of toxic substances or antibiotics, and the generation or conversion of energy. The last years have witnessed completion of a plethora of whole-genome sequences of bacteria important for biotechnology or medicine, which is the foundation for proteome and other functional genome analyses. In this review, we discuss the challenges in membrane proteome analysis, starting from sample preparation and leading to MS-data analysis and quantification. The current state of available proteomics technologies as well as their advantages and disadvantages will be described with a focus on shotgun proteomics. Then, we will briefly introduce the most abundant proteins and protein families present in bacterial membranes before bacterial membrane proteomics studies of the last years will be presented. It will be shown how these works enlarged our knowledge about the physiological adaptations that take place in bacteria during fine chemical production, bioremediation, protein overexpression, and during infections. Furthermore, several examples from literature demonstrate the suitability of membrane proteomics for the identification of antigens and different pathogenic strains, as well as the elucidation of membrane protein structure and function.

  8. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-10-01

    This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  9. Biomimetic membranes and methods of making biomimetic membranes

    Science.gov (United States)

    Rempe, Susan; Brinker, Jeffrey C.; Rogers, David Michael; Jiang, Ying-Bing; Yang, Shaorong

    2016-11-08

    The present disclosure is directed to biomimetic membranes and methods of manufacturing such membranes that include structural features that mimic the structures of cellular membrane channels and produce membrane designs capable of high selectivity and high permeability or adsorptivity. The membrane structure, material and chemistry can be selected to perform liquid separations, gas separation and capture, ion transport and adsorption for a variety of applications.

  10. Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine

    2013-01-01

    This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

  11. Smart membranes for monitoring membrane based desalination processes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-10-12

    Various examples are related to smart membranes for monitoring membrane based process such as, e.g., membrane distillation processes. In one example, a membrane, includes a porous surface and a plurality of sensors (e.g., temperature, flow and/or impedance sensors) mounted on the porous surface. In another example, a membrane distillation (MD) process includes the membrane. Processing circuitry can be configured to monitor outputs of the plurality of sensors. The monitored outputs can be used to determine membrane degradation, membrane fouling, or to provide an indication of membrane replacement or cleaning. The sensors can also provide temperatures or temperature differentials across the porous surface, which can be used to improve modeling or control the MD process.

  12. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2017-01-01

    Full Text Available Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest flux was achieved with the thinnest membranes and the best energy efficiency was achieved with the thickest membranes. All membranes had salt retention above 99%. Nanotechnology offers the potential to find modern solutions for desalination of waste waters, by introducing new materials with revolutionary properties, but new membranes must be developed according to the target application.

  13. Recent advances on polymeric membranes for membrane reactors

    KAUST Repository

    Buonomenna, M. G.

    2012-06-24

    Membrane reactors are generally applied in high temperature reactions (>400 °C). In the field of fine chemical synthesis, however, much milder conditions are generally applicable and polymeric membranes were applied without their damage. The successful use of membranes in membrane reactors is primary the result of two developments concerning: (i) membrane materials and (ii) membrane structures. The selection of a suited material and preparation technique depends on the application the membrane is to be used in. In this chapter a review of up to date literature about polymers and configuration catalyst/ membranes used in some recent polymeric membrane reactors is given. The new emerging concept of polymeric microcapsules as catalytic microreactors has been proposed. © 2012 Bentham Science Publishers. All rights reserved.

  14. Physics of biological membranes

    Science.gov (United States)

    Mouritsen, Ole G.

    The biological membrane is a complex system consisting of an aqueous biomolecular planar aggregate of predominantly lipid and protein molecules. At physiological temperatures, the membrane may be considered a thin (˜50Å) slab of anisotropic fluid characterized by a high lateral mobility of the various molecular components. A substantial fraction of biological activity takes place in association with membranes. As a very lively piece of condensed matter, the biological membrane is a challenging research topic for both the experimental and theoretical physicists who are facing a number of fundamental physical problems including molecular self-organization, macromolecular structure and dynamics, inter-macromolecular interactions, structure-function relationships, transport of energy and matter, and interfacial forces. This paper will present a brief review of recent theoretical and experimental progress on such problems, with special emphasis on lipid bilayer structure and dynamics, lipid phase transitions, lipid-protein and lipid-cholesterol interactions, intermembrane forces, and the physical constraints imposed on biomembrane function and evolution. The paper advocates the dual point of view that there are a number of interesting physics problems in membranology and, at the same time, that the physical properties of biomembranes are important regulators of membrane function.

  15. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence spectrosc......Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...... spectroscopy approaches provide very valuable structurally and dynamically related information on membranes, they generally produce mean parameters from data collected on bulk solutions of many vesicles and lack direct information on the spatial organization at the level of single membranes, a quality that can...... be provided by microscopy-related techniques. In this chapter, I will attempt to summarize representative examples concerning how microscopy (which provides information on membrane lateral organization by direct visualization) and spectroscopy techniques (which provides information about molecular interaction...

  16. Biopores/membrane proteins in synthetic polymer membranes.

    Science.gov (United States)

    Garni, Martina; Thamboo, Sagana; Schoenenberger, Cora-Ann; Palivan, Cornelia G

    2017-04-01

    Mimicking cell membranes by simple models based on the reconstitution of membrane proteins in lipid bilayers represents a straightforward approach to understand biological function of these proteins. This biomimetic strategy has been extended to synthetic membranes that have advantages in terms of chemical and mechanical stability, thus providing more robust hybrid membranes. We present here how membrane proteins and biopores have been inserted both in the membrane of nanosized and microsized compartments, and in planar membranes under various conditions. Such bio-hybrid membranes have new properties (as for example, permeability to ions/molecules), and functionality depending on the specificity of the inserted biomolecules. Interestingly, membrane proteins can be functionally inserted in synthetic membranes provided these have appropriate properties to overcome the high hydrophobic mismatch between the size of the biomolecule and the membrane thickness. Functional insertion of membrane proteins and biopores in synthetic membranes of compartments or in planar membranes is possible by an appropriate selection of the amphiphilic copolymers, and conditions of the self-assembly process. These hybrid membranes have new properties and functionality based on the specificity of the biomolecules and the nature of the synthetic membranes. Bio-hybrid membranes represent new solutions for the development of nanoreactors, artificial organelles or active surfaces/membranes that, by further gaining in complexity and functionality, will promote translational applications. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider. Copyright © 2016. Published by Elsevier B.V.

  17. Liver plasma membranes: an effective method to analyze membrane proteome.

    Science.gov (United States)

    Cao, Rui; Liang, Songping

    2012-01-01

    Plasma membrane proteins are critical for the maintenance of biological systems and represent important targets for the treatment of disease. The hydrophobicity and low abundance of plasma membrane proteins make them difficult to analyze. The protocols given here are the efficient isolation/digestion procedures for liver plasma membrane proteomic analysis. Both protocol for the isolation of plasma membranes and protocol for the in-gel digestion of gel-embedded plasma membrane proteins are presented. The later method allows the use of a high detergent concentration to achieve efficient solubilization of hydrophobic plasma membrane proteins while avoiding interference with the subsequent LC-MS/MS analysis.

  18. Membranes and pathophysiological mineralization.

    Science.gov (United States)

    Roszkowska, Monika; Strzelecka-Kiliszek, Agnieszka; Magne, David; Pikula, Slawomir; Bessueille, Laurence

    Vascular calcification accompanies the pathological process of atherosclerotic plaque formation. Artery calcification results from trans-differentiation of vascular smooth muscle cells (VSMCs) into cells resembling mineralization-competent cells such as osteoblasts and chondrocytes. The activity of tissue-nonspecific alkaline phosphatase (TNAP), a GPI-anchored enzyme necessary for physiological mineralization, is induced in VSMCs in response to inflammation. TNAP achieves its mineralizing function being anchored to plasma membrane of mineralizing cells and to the surface of their derived matrix vesicles (MVs), and numerous important reports indicate that membranes play a crucial role in initiating the crystal formation. In this review, we would like to highlight various functions of lipids and proteins associated to membranes at different stages of both physiological mineralization and vascular calcification, with an emphasis on the pathological process of atherosclerotic plaque formation.

  19. Characterization of graphene membranes

    Science.gov (United States)

    O'Hern, Sean; Lee, Jongho; Jain, Tarun; Karnik, Rohit; Idrobo, Juan; Laoui, Tahar; Atieh, Motaz

    2011-11-01

    Graphene, which exhibits very high breaking strength, atomistic thickness, and the ability to maintain stable nanometer-scale pores, has the potential to be a superior membrane material in both liquid- and gas-phase separation processes. We have recently demonstrated high-quality transfer of ~1 cm2 LPCVD graphene from copper foil to 200 nm polycarbonate track etch membranes with less than 0.3% of the area constituting holes or tears in the graphene, which is essential for characterizing transport through graphene. Through gallium ion bombardment we have introduced nanometer-scale pores in the transferred graphene and will report on the molecular and ionic transport through these membranes. Funded by the Center for Clean Energy and Water at MIT and KFUPM.

  20. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  1. Membrane adsorber for endotoxin removal

    Directory of Open Access Journals (Sweden)

    Karina Moita de Almeida

    Full Text Available ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.

  2. Fouling resistant membrane spacers

    KAUST Repository

    Ghaffour, Noreddine

    2017-10-12

    Disclosed herein are spacers having baffle designs and perforations for efficiently and effectively separating one or more membrane layers a membrane filtration system. The spacer (504) includes a body (524) formed at least in part by baffles (520) that are interconnected, and the baffles define boundaries of openings or apertures (525) through a thickness direction of the body of the spacer. Alternatively or additionally, passages or perforations (526A, 526B) may be present in the spacer layer or baffles for fluid flow there through, with the passages and baffles having a numerous different shapes and sizes.

  3. Mitigating leaks in membranes

    Energy Technology Data Exchange (ETDEWEB)

    Karnik, Rohit N.; Bose, Suman; Boutilier, Michael S.H.; Hadjiconstantinou, Nicolas G.; Jain, Tarun Kumar; O' Hern, Sean C.; Laoui, Tahar; Atieh, Muataz A.; Jang, Doojoon

    2018-02-27

    Two-dimensional material based filters, their method of manufacture, and their use are disclosed. In one embodiment, a membrane may include an active layer including a plurality of defects and a deposited material associated with the plurality of defects may reduce flow therethrough. Additionally, a majority of the active layer may be free from the material. In another embodiment, a membrane may include a porous substrate and an atomic layer deposited material disposed on a surface of the porous substrate. The atomic layer deposited material may be less hydrophilic than the porous substrate and an atomically thin active layer may be disposed on the atomic layer deposited material.

  4. Organic separations with membranes

    International Nuclear Information System (INIS)

    Funk, E.W.

    1993-01-01

    This paper presents an overview of present and emerging applications of membrane technology for the separation and purification of organic materials. This technology is highly relevant for programs aimed at minimizing waste in processing and in the treatment of gaseous and liquid effluents. Application of membranes for organic separation is growing rapidly in the petrochemical industry to simplify processing and in the treatment of effluents, and it is expected that this technology will be useful in numerous other industries including the processing of nuclear waste materials

  5. Membrane order in the plasma membrane and endocytic recycling compartment.

    Science.gov (United States)

    Iaea, David B; Maxfield, Frederick R

    2017-01-01

    The cholesterol content of membranes plays an important role in organizing membranes for signal transduction and protein trafficking as well as in modulating the biophysical properties of membranes. While the properties of model or isolated membranes have been extensively studied, there has been little evaluation of internal membranes in living cells. Here, we use a Nile Red based probe, NR12S, and ratiometric live cell imaging, to analyze the membrane order of the plasma membrane and endocytic recycling compartment. We find that after a brief incubation to allow endocytosis, NR12S is distributed between the plasma membrane and the endocytic recycling compartment. The NR12S reports that the endocytic recycling compartment is more highly ordered than the plasma membrane. We also find that the plasma membrane and the endocytic recycling compartment are differentially affected by altering cellular cholesterol levels. The membrane order of the plasma membrane, but not the endocytic recycling compartment, is altered significantly when cellular cholesterol content is increased or decreased by 20%. These results demonstrate that changes in cellular cholesterol differentially alter membrane order within different organelles.

  6. Dimensional analysis of membrane distillation flux through fibrous membranes

    Science.gov (United States)

    Mauter, Meagan

    We developed a dimensional-analysis-based empirical modeling method for membrane distillation (MD) flux that is adaptable for novel membrane structures. The method makes fewer simplifying assumptions about membrane pore geometry than existing theoretical (i.e. mechanistic) models, and allows selection of simple, easily-measureable membrane characteristics as structural parameters. Furthermore, the model does not require estimation of membrane surface temperatures; it accounts for convective heat transfer to the membrane surface without iterative fitting of mass and heat transfer equations. The Buckingham-Pi dimensional analysis method is tested for direct contact membrane distillation (DCMD) using non-woven/fibrous structures as the model membrane material. Twelve easily-measured variables to describe DCMD operating conditions, fluid properties, membrane structures, and flux were identified and combined into eight dimensionless parameters. These parameters were regressed using experimentally-collected data for multiple electrospun membrane types and DCMD system conditions, achieving R2 values >95%. We found that vapor flux through isotropic fibrous membranes can be estimated using only membrane thickness, solid fraction, and fiber diameter as structural parameters. Buckingham-Pi model DCMD flux predictions compare favorably with previously-developed empirical and theoretical models, and suggest this simple yet theoretically-grounded empirical modeling method can be used practically for predicting MD vapor flux from membrane structural parameters.

  7. Fouling in Membrane Distillation, Osmotic Distillation and Osmotic Membrane Distillation

    Directory of Open Access Journals (Sweden)

    Mourad Laqbaqbi

    2017-03-01

    Full Text Available Various membrane separation processes are being used for seawater desalination and treatment of wastewaters in order to deal with the worldwide water shortage problem. Different types of membranes of distinct morphologies, structures and physico-chemical characteristics are employed. Among the considered membrane technologies, membrane distillation (MD, osmotic distillation (OD and osmotic membrane distillation (OMD use porous and hydrophobic membranes for production of distilled water and/or concentration of wastewaters for recovery and recycling of valuable compounds. However, the efficiency of these technologies is hampered by fouling phenomena. This refers to the accumulation of organic/inorganic deposits including biological matter on the membrane surface and/or in the membrane pores. Fouling in MD, OD and OMD differs from that observed in electric and pressure-driven membrane processes such electrodialysis (ED, membrane capacitive deionization (MCD, reverse osmosis (RO, nanofiltration (NF, ultrafiltration (UF, microfiltration (MF, etc. Other than pore blockage, fouling in MD, OD and OMD increases the risk of membrane pores wetting and reduces therefore the quantity and quality of the produced water or the concentration efficiency of the process. This review deals with the observed fouling phenomena in MD, OD and OMD. It highlights different detected fouling types (organic fouling, inorganic fouling and biofouling, fouling characterization techniques as well as various methods of fouling reduction including pretreatment, membrane modification, membrane cleaning and antiscalants application.

  8. Microencapsulation within crosslinked polyethyleneimine membranes.

    Science.gov (United States)

    Poncelet, D; Alexakis, T; Poncelet de Smet, B; Neufeld, R J

    1994-01-01

    A microencapsulation technique is proposed involving the formation of a polyethyleneimine (PEI) membrane crosslinked by an acid dichloride. The membranes were formed at pH 8 in a non-polar solvent, conditions which are better suited for the encapsulation of biocatalysts or fragile biochemicals than those using polyamide membranes. The mean diameter and size distribution of the PEI microcapsules were similar to that observed with nylon membranes. The resultant microcapsules were spherical, free-flowing with a strong membrane. The mass of membrane was seen to be independent of the reaction time (1-4 min), insensitive to the PEI concentration and proportional to the concentration of crosslinking agent.

  9. Giant plasma membrane vesicles: models for understanding membrane organization.

    Science.gov (United States)

    Levental, Kandice R; Levental, Ilya

    2015-01-01

    The organization of eukaryotic membranes into functional domains continues to fascinate and puzzle cell biologists and biophysicists. The lipid raft hypothesis proposes that collective lipid interactions compartmentalize the membrane into coexisting liquid domains that are central to membrane physiology. This hypothesis has proven controversial because such structures cannot be directly visualized in live cells by light microscopy. The recent observations of liquid-liquid phase separation in biological membranes are an important validation of the raft hypothesis and enable application of the experimental toolbox of membrane physics to a biologically complex phase-separated membrane. This review addresses the role of giant plasma membrane vesicles (GPMVs) in refining the raft hypothesis and expands on the application of GPMVs as an experimental model to answer some of key outstanding problems in membrane biology. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Adaptive silicone-membrane lenses: planar vs. shaped membrane

    CSIR Research Space (South Africa)

    Schneider, F

    2009-08-01

    Full Text Available In this paper the authors compare the performance and optical quality of two types of adaptive fluidic silicone-membrane lenses. The membranes feature either a homogeneous thickness, or it is shaped resulting in an inhomogeneous cross...

  11. Hydrogen-selective membrane

    Science.gov (United States)

    Collins, J.P.; Way, J.D.

    1997-07-29

    A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 {micro}m but typically less than about 20 {micro}m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m{sup 2} s at a temperature of greater than about 500 C and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500 C and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400 C and less than about 1000 C before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process. 9 figs.

  12. Fusion of biological membranes

    Indian Academy of Sciences (India)

    small hemifusion diaphragm. To obtain a direct view of the fusion process, we have carried out extensive simulations of two bilayers, composed of block copolymers, which are immersed in a solvent which favors one of the blocks. As in the biological case, the membranes are placed under tension. This is essential as fusion ...

  13. Cell Membrane Coating Nanotechnology.

    Science.gov (United States)

    Fang, Ronnie H; Kroll, Ashley V; Gao, Weiwei; Zhang, Liangfang

    2018-03-27

    Nanoparticle-based therapeutic, prevention, and detection modalities have the potential to greatly impact how diseases are diagnosed and managed in the clinic. With the wide range of nanomaterials available, the rational design of nanocarriers on an application-specific basis has become increasingly commonplace. Here, a comprehensive overview is provided on an emerging platform: cell-membrane-coating nanotechnology. As a fundamental unit of biology, cells carry out a wide range of functions, including the remarkable ability to interface and interact with their surrounding environment. Instead of attempting to replicate such functions via synthetic techniques, researchers are now directly leveraging naturally derived cell membranes as a means of bestowing nanoparticles with enhanced biointerfacing capabilities. This top-down technique is facile, highly generalizable, and has the potential to greatly augment existing nanocarriers. Further, the introduction of a natural membrane substrate onto nanoparticles surfaces has enabled additional applications beyond those traditionally associated with nanomedicine. Despite its relative youth, there exists an impressive body of literature on cell membrane coating, which is covered here in detail. Overall, there is still significant room for development, as researchers continue to refine existing workflows while finding new and exciting applications that can take advantage of this developing technology. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Fusion of biological membranes

    Indian Academy of Sciences (India)

    Logo of the Indian Academy of Sciences. Indian Academy of ... Home; Journals; Pramana – Journal of Physics; Volume 64; Issue 6. Fusion of biological ... The process of membrane fusion has been examined by Monte Carlo simulation, and is found to be very different than the conventional picture. The differences in ...

  15. Bioelectrochemistry II membrane phenomena

    CERN Document Server

    Blank, M

    1987-01-01

    This book contains the lectures of the second course devoted to bioelectro­ chemistry, held within the framework of the International School of Biophysics. In this course another very large field of bioelectrochemistry, i. e. the field of Membrane Phenomena, was considered, which itself consists of several different, but yet related subfields. Here again, it can be easily stated that it is impossible to give a complete and detailed picture of all membrane phenomena of biological interest in a short course of about one and half week. Therefore the same philosophy, as the one of the first course, was followed, to select a series of lectures at postgraduate level, giving a synthesis of several membrane phenomena chosen among the most'important ones. These lectures should show the large variety of membrane-regulated events occurring in living bodies, and serve as sound interdisciplinary basis to start a special­ ized study of biological phenomena, for which the investigation using the dual approach, physico-che...

  16. Fusion of biological membranes

    Indian Academy of Sciences (India)

    Abstract. The process of membrane fusion has been examined by Monte Carlo simu- lation, and is found to be very different than the conventional picture. The differences in mechanism lead to several predictions, in particular that fusion is accompanied by tran- sient leakage. This prediction has recently been verified.

  17. Extracorporeal membrane oxygenation (ECMO)

    African Journals Online (AJOL)

    Extracorporeal membrane oxygenation (ECMO) is increasingly being employed in South African intensive care units for the management of patients with refractory hypoxaemia and for haemodynamic support, particularly following cardiothoracic procedures. ECMO is expensive, however, and there is a danger that this ...

  18. Fusion of biological membranes

    Indian Academy of Sciences (India)

    The process of membrane fusion has been examined by Monte Carlo simulation, and is found to be very different than the conventional picture. The differences in mechanism lead to several predictions, in particular that fusion is accompanied by transient leakage. This prediction has recently been verified. Self-consistent ...

  19. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2001-02-01

    This is the fifth quarterly report on a new study to develop a ceramic membrane/metal joint. Results of wetting experiments on commercially available Nickel based brazing alloys on perovskite surfaces are described. Additionally, experimental and numerical investigations on the strength of concentric ceramic/metal joints are presented.

  20. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01

    In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  1. Nanodisc-solubilized membrane protein library reflects the membrane proteome

    OpenAIRE

    Marty, Michael T.; Wilcox, Kyle C.; Klein, William L.; Sligar, Stephen G.

    2013-01-01

    The isolation and identification of unknown membrane proteins offers the prospect of discovering new pharmaceutical targets and identifying key biochemical receptors. However, interactions between membrane protein targets and soluble ligands are difficult to study in vitro due to the insolubility of membrane proteins in non-detergent systems. Nanodiscs, nanoscale discoidal lipid bilayers encircled by a membrane scaffold protein belt, have proven to be an effective platform to solubilize membr...

  2. Membrane fission by protein crowding.

    Science.gov (United States)

    Snead, Wilton T; Hayden, Carl C; Gadok, Avinash K; Zhao, Chi; Lafer, Eileen M; Rangamani, Padmini; Stachowiak, Jeanne C

    2017-04-18

    Membrane fission, which facilitates compartmentalization of biological processes into discrete, membrane-bound volumes, is essential for cellular life. Proteins with specific structural features including constricting rings, helical scaffolds, and hydrophobic membrane insertions are thought to be the primary drivers of fission. In contrast, here we report a mechanism of fission that is independent of protein structure-steric pressure among membrane-bound proteins. In particular, random collisions among crowded proteins generate substantial pressure, which if unbalanced on the opposite membrane surface can dramatically increase membrane curvature, leading to fission. Using the endocytic protein epsin1 N-terminal homology domain (ENTH), previously thought to drive fission by hydrophobic insertion, our results show that membrane coverage correlates equally with fission regardless of the hydrophobicity of insertions. Specifically, combining FRET-based measurements of membrane coverage with multiple, independent measurements of membrane vesiculation revealed that fission became spontaneous as steric pressure increased. Further, fission efficiency remained equally potent when helices were replaced by synthetic membrane-binding motifs. These data challenge the view that hydrophobic insertions drive membrane fission, suggesting instead that the role of insertions is to anchor proteins strongly to membrane surfaces, amplifying steric pressure. In line with these conclusions, even green fluorescent protein (GFP) was able to drive fission efficiently when bound to the membrane at high coverage. Our conclusions are further strengthened by the finding that intrinsically disordered proteins, which have large hydrodynamic radii yet lack a defined structure, drove fission with substantially greater potency than smaller, structured proteins.

  3. Dialysis membranes for blood purification.

    Science.gov (United States)

    Sakai, K

    2000-01-01

    All of the artificial membranes in industrial use, such as a reverse-osmosis membrane, dialysis membrane, ultrafiltration membrane, microfiltration membrane and gas separation membrane, also have therapeutic applications. The most commonly used artificial organ is the artificial kidney, a machine that performs treatment known as hemodialysis. This process cleanses the body of a patient with renal failure by dialysis and filtration, simple physicochemical processes. Hemodialysis membranes are used to remove accumulated uremic toxins, excess ions and water from the patient via the dialysate, and to supply (deficit) insufficient ions from the dialysate. Dialysis membranes used clinically in the treatment of patients with renal failure account for by far the largest volume of membranes used worldwide; more than 70 million square meters are used a year. Almost all dialyzers now in use are of the hollow-fiber type. A hollow-fiber dialyzer contains a bundle of approximately 10000 hollow fibers, each with an inner diameter of about 200 microm when wet. The membrane thickness is about 20-45 microm, and the length is 160-250 mm. The walls of the hollow fibers function as the dialysis membrane. Various materials, including cellulose-based materials and synthetic polymers, are used for dialysis membranes. This paper reviews blood purification, hemodialysis and dialysis membranes.

  4. Identification by affinity chromatography of boar sperm membrane-associated proteins bound to immobilized porcine zona pellucida. Mapping of the phosphorylethanolamine-binding region of spermadhesin AWN.

    Science.gov (United States)

    Ensslin, M; Calvete, J J; Thole, H H; Sierralta, W D; Adermann, K; Sanz, L; Töpfer-Petersen, E

    1995-12-01

    We have identified boar sperm membrane components recovered by affinity chromatography on a porcine zona pellucida affinity column. The major zona pellucida-bound proteins were spermadhesins AWN and AQN-3, the heparin-binding protein pAIF, and a homolog of the mouse milk fat globule membrane protein. All these proteins are phospholipid-binding proteins peripherally associated with the plasma membrane. Our data suggest that coating proteins tightly bound to the external lipid bilayer may act as major zona pellucida-binding molecules. Using a synthetic peptide approach we show that the regions of spermadhesin AWN comprising residues 6-12 and 104-108 possess affinity for phosphorylethanolamine. These two amino acid sequences are in close proximity in the predicted structural model for AWN, and in opposite location to its carbohydrate-recognition domain. Taken together, our data provide further evidence for the possible involvement of members of the porcine spermadhesin protein family in gamete interaction and suggest a model for the ultrastructural disposition of functional domains of spermadhesin AWN bound to the sperm surface.

  5. Autophagosomal membranes assemble at ER-plasma membrane contact sites.

    Science.gov (United States)

    Nascimbeni, Anna Chiara; Codogno, Patrice; Morel, Etienne

    2017-01-01

    The biogenesis of autophagosome, the double membrane bound organelle related to macro-autophagy, is a complex event requiring numerous key-proteins and membrane remodeling events. Our recent findings identify the extended synaptotagmins, crucial tethers of Endoplasmic Reticulum-plasma membrane contact sites, as key-regulators of this molecular sequence.

  6. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane.

    Science.gov (United States)

    Ho, J; Smith, S; Roh, H K

    2014-01-01

    A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m(2)/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m(3) permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m(3)). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude.

  7. Nanodisc-solubilized membrane protein library reflects the membrane proteome.

    Science.gov (United States)

    Marty, Michael T; Wilcox, Kyle C; Klein, William L; Sligar, Stephen G

    2013-05-01

    The isolation and identification of unknown membrane proteins offers the prospect of discovering new pharmaceutical targets and identifying key biochemical receptors. However, interactions between membrane protein targets and soluble ligands are difficult to study in vitro due to the insolubility of membrane proteins in non-detergent systems. Nanodiscs, nanoscale discoidal lipid bilayers encircled by a membrane scaffold protein belt, have proven to be an effective platform to solubilize membrane proteins and have been used to study a wide variety of purified membrane proteins. This report details the incorporation of an unbiased population of membrane proteins from Escherichia coli membranes into Nanodiscs. This solubilized membrane protein library (SMPL) forms a soluble in vitro model of the membrane proteome. Since Nanodiscs contain isolated proteins or small complexes, the SMPL is an ideal platform for interactomics studies and pull-down assays of membrane proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the protein population before and after formation of the Nanodisc library indicates that a large percentage of the proteins are incorporated into the library. Proteomic identification of several prominent bands demonstrates the successful incorporation of outer and inner membrane proteins into the Nanodisc library.

  8. Membrane Cells for Brine Electrolysis.

    Science.gov (United States)

    Tingle, M.

    1982-01-01

    Membrane cells were developed as alternatives to mercury and diaphragm cells for the electrolysis of brine. Compares the three types of cells, focusing on the advantages and disadvantages of membrane cells. (JN)

  9. Modelling of proteins in membranes

    DEFF Research Database (Denmark)

    Sperotto, Maria Maddalena; May, S.; Baumgaertner, A.

    2006-01-01

    This review describes some recent theories and simulations of mesoscopic and microscopic models of lipid membranes with embedded or attached proteins. We summarize results supporting our understanding of phenomena for which the activities of proteins in membranes are expected to be significantly...... oppositely charged lipid membranes, lipid-induced tilting of proteins embedded in lipid bilayers, protein-induced bilayer deformations, protein insertion and assembly, and lipid-controlled functioning of membrane proteins....

  10. Fundamentals of membrane bioreactors materials, systems and membrane fouling

    CERN Document Server

    Ladewig, Bradley

    2017-01-01

    This book provides a critical, carefully researched, up-to-date summary of membranes for membrane bioreactors. It presents a comprehensive and self-contained outline of the fundamentals of membrane bioreactors, especially their relevance as an advanced water treatment technology. This outline helps to bring the technology to the readers’ attention, and positions the critical topic of membrane fouling as one of the key impediments to its more widescale adoption. The target readership includes researchers and industrial practitioners with an interest in membrane bioreactors.

  11. Cheap Thin Film Oxygen Membranes

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention provides a membrane, comprising a porous support layer a gas tight electronically and ionically conducting membrane layer and a catalyst layer, characterized in that the electronically and ionically conducting membrane layer is formed from a material having a crystallite...

  12. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    . In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...

  13. Building membrane nanopores

    Science.gov (United States)

    Howorka, Stefan

    2017-07-01

    Membrane nanopores--hollow nanoscale barrels that puncture biological or synthetic membranes--have become powerful tools in chemical- and biosensing, and have achieved notable success in portable DNA sequencing. The pores can be self-assembled from a variety of materials, including proteins, peptides, synthetic organic compounds and, more recently, DNA. But which building material is best for which application, and what is the relationship between pore structure and function? In this Review, I critically compare the characteristics of the different building materials, and explore the influence of the building material on pore structure, dynamics and function. I also discuss the future challenges of developing nanopore technology, and consider what the next-generation of nanopore structures could be and where further practical applications might emerge.

  14. Aquaporin-2 membrane targeting

    DEFF Research Database (Denmark)

    Olesen, Emma T B; Fenton, Robert A

    2017-01-01

    The targeting of the water channel aquaporin-2 (AQP2) to the apical plasma membrane of kidney collecting duct principal cells is regulated mainly by the antidiuretic peptide hormone arginine vasopressin (AVP). This process is of crucial importance for the maintenance of body water homeostasis....... In this brief review we assess the role of cyclic adenosine monophosphate (cAMP) and discuss the emerging concept that type 2 AVP receptor (V2R)-mediated AQP2 trafficking is cAMP-independent. the ability of the kidney to concentrate the urine and thereby maintain body water homeostasis depends on targeting....... For example, 1) stimulation with the nonspecific AC activator forskolin increases AQP2 membrane accumulation in a mouse cortical collecting duct cell line [e.g., Norregaard et al. (16)]; 2) cAMP increases CD water permeability (15); 3) the cAMP-activated protein kinase A (PKA) can phosphorylate AQP2 on its...

  15. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01

    In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Processing of perovskites of LSC, LSF and LSCF composition for evaluation of mechanical properties as a function of environment are begun. The studies are to be in parallel with LSFCO composition to characterize the segregation of cations and slow crack growth in environmental conditions. La{sub 1-x}Sr{sub x}FeO{sub 3-d} has also been characterized for paramagnetic ordering at room temperature and the evolution of magnetic moments as a function of temperature are investigated. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport.

  16. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    OpenAIRE

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become more attractive and feasible, due to advantages provided by the combination with regard to developments for energy-efficient wastewater treatment. The major drawbacks of MBR technology are related w...

  17. Pulse radiolysis studies of model membranes

    International Nuclear Information System (INIS)

    Heijman, M.G.J.

    1984-01-01

    In this thesis the influence of the structure of membranes on the processes in cell membranes were examined. Different models of the membranes were evaluated. Pulse radiolysis was used as the technique to examine the membranes. (R.B.)

  18. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  19. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-07-01

    This is the fourth quarterly report on a new study to develop a ceramic membrane/metal joint. The first experiments using the La-Sr-Fe-O ceramic are reported. Some of the analysis performed on the samples obtained are commented upon. A set of experiments to characterize the mechanical strength and thermal fatigue properties of the joints has been designed and begun. Finite element models of joints used to model residual stresses are described.

  20. Novicidin interactions with phospholipid membranes

    DEFF Research Database (Denmark)

    Balakrishnan, Vijay Shankar

    Antimicrobial peptides target bacterial cell membranes and are considered as potential antibiotics. Their interactions with cell membranes are studied using different approaches. This thesis comprises of the biophysical investigations on the antimicrobial peptide Novicidin, interacting...... with liposomes. The lipid-induced changes in the peptide due to membrane binding, and the peptide-induced changes in the membrane properties were investigated using various spectroscopic and calorimetric methods, and the structural and thermodynamic aspects of peptide-lipid interactions are discussed. This helps...... in understanding not only the antimicrobial nature of Novicidin, but also sheds light on the membrane-peptide interactions....

  1. Quantum charged rigid membrane

    International Nuclear Information System (INIS)

    Cordero, Ruben; Molgado, Alberto; Rojas, Efrain

    2011-01-01

    The early Dirac proposal to model the electron as a charged membrane is reviewed. A rigidity term, instead of the natural membrane tension, involving linearly the extrinsic curvature of the worldvolume swept out by the membrane is considered in the action modeling the bubble in the presence of an electromagnetic field. We set up this model as a genuine second-order derivative theory by considering a non-trivial boundary term which plays a relevant part in our formulation. The Lagrangian in question is linear in the bubble acceleration and by means of the Ostrogradski-Hamiltonian approach, we observed that the theory comprises the management of both first- and second-class constraints. We thus show that our second-order approach is robust allowing for a proper quantization. We found an effective quantum potential which permits us to compute bounded states for the system. We comment on the possibility of describing brane world universes by invoking this kind of second-order correction terms.

  2. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  3. Viral membrane fusion

    International Nuclear Information System (INIS)

    Harrison, Stephen C.

    2015-01-01

    Membrane fusion is an essential step when enveloped viruses enter cells. Lipid bilayer fusion requires catalysis to overcome a high kinetic barrier; viral fusion proteins are the agents that fulfill this catalytic function. Despite a variety of molecular architectures, these proteins facilitate fusion by essentially the same generic mechanism. Stimulated by a signal associated with arrival at the cell to be infected (e.g., receptor or co-receptor binding, proton binding in an endosome), they undergo a series of conformational changes. A hydrophobic segment (a “fusion loop” or “fusion peptide”) engages the target-cell membrane and collapse of the bridging intermediate thus formed draws the two membranes (virus and cell) together. We know of three structural classes for viral fusion proteins. Structures for both pre- and postfusion conformations of illustrate the beginning and end points of a process that can be probed by single-virion measurements of fusion kinetics. - Highlights: • Viral fusion proteins overcome the high energy barrier to lipid bilayer merger. • Different molecular structures but the same catalytic mechanism. • Review describes properties of three known fusion-protein structural classes. • Single-virion fusion experiments elucidate mechanism

  4. Embryonic epithelial membrane transporters.

    Science.gov (United States)

    Horster, M

    2000-12-01

    Embryonic epithelial membrane transporters are organized into transporter families that are functional in several epithelial organs, namely, in kidney, lung, pancreas, intestine, and salivary gland. Family members (subtypes) are developmentally expressed in plasma membranes in temporospatial patterns that are 1) similar for one subtype within different organs, like aquaporin-1 (AQP1) in lung and kidney; 2) different between subtypes within the same organ, like the amiloride-sensitive epithelial sodium channel (ENaC) in lung; and 3) apparently matched among members of different transporter families, as alpha-ENaC with AQP1 and -4 in lung and with AQP2 in kidney. Finally, comparison of temporal expression patterns in early embryonic development of transporters from different families [e.g., cystic fibrosis transmembrane conductance regulator (CFTR), ENaC, and outer medullary potassium channel] suggests regulatory activating or inactivating interactions in defined morphogenic periods. This review focuses on embryonic patterns, at the mRNA and immunoprotein level, of the following transporter entities expressed in epithelial cell plasma membranes: ENaC; the chloride transporters CFTR, ClC-2, bumetanide-sensitive Na-K-Cl cotransporter, Cl/OH, and Cl/HCO(3); the sodium glucose transporter-glucose transporter; the sodium/hydrogen exchanger; the sodium-phosphate cotransporter; the ATPases; and AQP. The purpose of this article is to relate temporal and spatial expression patterns in embryonic and in early postnatal epithelia to developmental changes in organ structure and function.

  5. Quantum charged rigid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Ruben [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del I.P.N., Unidad Adolfo Lopez Mateos, Edificio 9, 07738 Mexico, D.F. (Mexico); Molgado, Alberto [Unidad Academica de Fisica, Universidad Autonoma de Zacatecas, Zacatecas Zac. (Mexico); Rojas, Efrain, E-mail: cordero@esfm.ipn.mx, E-mail: amolgado@fisica.uaz.edu.mx, E-mail: efrojas@uv.mx [Departamento de Fisica, Facultad de Fisica e Inteligencia Artificial, Universidad Veracruzana, 91000 Xalapa, Veracruz (Mexico)

    2011-03-21

    The early Dirac proposal to model the electron as a charged membrane is reviewed. A rigidity term, instead of the natural membrane tension, involving linearly the extrinsic curvature of the worldvolume swept out by the membrane is considered in the action modeling the bubble in the presence of an electromagnetic field. We set up this model as a genuine second-order derivative theory by considering a non-trivial boundary term which plays a relevant part in our formulation. The Lagrangian in question is linear in the bubble acceleration and by means of the Ostrogradski-Hamiltonian approach, we observed that the theory comprises the management of both first- and second-class constraints. We thus show that our second-order approach is robust allowing for a proper quantization. We found an effective quantum potential which permits us to compute bounded states for the system. We comment on the possibility of describing brane world universes by invoking this kind of second-order correction terms.

  6. Neutrons and model membranes

    Science.gov (United States)

    Fragneto, G.

    2012-11-01

    Current research in membrane protein biophysics highlights the emerging role of lipids in shaping membrane protein function. Cells and organisms have developed sophisticated mechanisms for controlling the lipid composition and many diseases are related to the failure of these mechanisms. One of the recent advances in the field is the discovery of the existence of coexisting micro-domains within a single membrane, important for regulating some signaling pathways. Many important properties of these domains remain poorly characterized. The characterization and analysis of bio-interfaces represent a challenge. Performing measurements on these few nanometer thick, soft, visco-elastic and dynamic systems is close to the limits of the available tools and methods. Neutron scattering techniques including small angle scattering, diffraction, reflectometry as well as inelastic methods are rapidly developing for these studies and are attracting an increasing number of biologists and biophysicists at large facilities. This manuscript will review some recent progress in the field and provide perspectives for future developments. It aims at highlighting neutron reflectometry as a versatile method to tackle questions dealing with the understanding and function of biomembranes and their components. The other important scattering methods are only briefly introduced.

  7. Solid-state membrane module

    Science.gov (United States)

    Gordon, John Howard [Salt Lake City, UT; Taylor, Dale M [Murray, UT

    2011-06-07

    Solid-state membrane modules comprising at least one membrane unit, where the membrane unit has a dense mixed conducting oxide layer, and at least one conduit or manifold wherein the conduit or manifold comprises a dense layer and at least one of a porous layer and a slotted layer contiguous with the dense layer. The solid-state membrane modules may be used to carry out a variety of processes including the separating of any ionizable component from a feedstream wherein such ionizable component is capable of being transported through a dense mixed conducting oxide layer of the membrane units making up the membrane modules. For ease of construction, the membrane units may be planar.

  8. Flux Enhancement in Membrane Distillation Using Nanofiber Membranes

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2016-01-01

    Full Text Available Membrane distillation (MD is an emerging separation technology, whose largest application potential lies in the desalination of highly concentrated solutions, which are out of the scope of reverse osmosis. Despite many attractive features, this technology is still awaiting large industrial application. The main reason is the lack of commercially available membranes with fluxes comparable to reverse osmosis. MD is a thermal separation process driven by a partial vapour pressure difference. Flux, distillate purity, and thermal efficiency are always in conflict, all three being strictly connected with pore size, membrane hydrophobicity, and thickness. The world has not seen the ideal membrane yet, but nanofibers may offer a solution to these contradictory requirements. Membranes of electrospun PVDF were tested under various conditions on a direct contact (DCMD unit, in order to determine the optimum conditions for maximum flux. In addition, their performance was compared to commonly available PTFE, PE, and PES membranes. It was confirmed that thinner membranes have higher fluxes and a lower distillate purity and also higher energy losses via conduction across the membrane. As both mass and heat transfer are connected, it is best to develop new membranes with a target application in mind, for the specific membrane module and operational conditions.

  9. Membranes, methods of making membranes, and methods of separating gases using membranes

    Science.gov (United States)

    Ho, W. S. Winston

    2012-10-02

    Membranes, methods of making membranes, and methods of separating gases using membranes are provided. The membranes can include at least one hydrophilic polymer, at least one cross-linking agent, at least one base, and at least one amino compound. The methods of separating gases using membranes can include contacting a gas stream containing at least one of CO.sub.2, H.sub.2S, and HCl with one side of a nonporous and at least one of CO.sub.2, H.sub.2S, and HCl selectively permeable membrane such that at least one of CO.sub.2, H.sub.2S, and HCl is selectively transported through the membrane.

  10. Polyazole hollow fiber membranes for direct contact membrane distillation

    KAUST Repository

    Maab, Husnul

    2013-08-07

    Porous hollow fiber membranes were fabricated from fluorinated polyoxadiazole and polytriazole by a dry-wet spinning method for application in desalination of Red Sea water by direct contact membrane distillation (DCMD). The data were compared with commercially available hollow fiber MD membranes prepared from poly(vinylidene fluoride). The membranes were characterized by electron microscopy, liquid entry pressure (LEP), and pore diameter measurements. Finally, the hollow fiber membranes were tested for DCMD. Salt selectivity as high as 99.95% and water fluxes as high as 35 and 41 L m -2 h-1 were demonstrated, respectively, for polyoxadiazole and polytriazole hollow fiber membranes, operating at 80 C feed temperature and 20 C permeate. © 2013 American Chemical Society.

  11. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various thermopl......A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  12. Amodiaquine polymeric membrane electrode.

    Science.gov (United States)

    Malongo, T Kimbeni; Blankert, B; Kambu, O; Amighi, K; Nsangu, J; Kauffmann, J-M

    2006-04-11

    The construction and electrochemical response characteristics of two types of poly(vinyl chloride) (PVC) membrane sensors for the determination of amodiaquine hydrochloride (ADQ.2HCl) are described. The sensing membrane comprised an ion-pair formed between the cationic drug and sodium tetraphenyl borate (NaTPB) or potassium tetrakis(4-chlorophenyl) borate (KTCPB) in a plasticized PVC matrix. Eight PVC membrane ion-selective electrodes were fabricated and studied. Several plasticizers were studied namely, dioctyl phthalate (DOP), 2-nitrophenyl octyl ether (NPOE), dioctyl phenylphosphonate (DOPP) and bis(2-ethylhexyl)adipate (EHA). The sensors display a fast, stable and near-Nernstian response over a relative wide ADQ concentration range (3.2 x 10(-6) to 2.0 x 10(-2) M), with slopes comprised between 28.5 and 31.4 mV dec(-1) in a pH range comprised between pH 3.7 and 5.5. The assay of amodiaquine hydrochloride in pharmaceutical dosage forms using one of the proposed sensors gave average recoveries of 104.3 and 99.9 with R.S.D. of 0.3 and 0.6% for tablets (Malaritab) and a reconstituted powder containing ADQ.2HCl, respectively. The sensor was also used for dissolution profile studies of two drug formulations. The sensor proved to have a good selectivity for ADQ.2HCl over some inorganic and organic compounds, however, berberine chloride interfered significantly. The results were validated by comparison with a spectrophotometric assay according to the USP pharmacopoeia.

  13. Molecularly Imprinted Membranes

    Science.gov (United States)

    Trotta, Francesco; Biasizzo, Miriam; Caldera, Fabrizio

    2012-01-01

    Although the roots of molecularly imprinted polymers lie in the beginning of 1930s in the past century, they have had an exponential growth only 40–50 years later by the works of Wulff and especially by Mosbach. More recently, it was also proved that molecular imprinted membranes (i.e., polymer thin films) that show recognition properties at molecular level of the template molecule are used in their formation. Different procedures and potential application in separation processes and catalysis are reported. The influences of different parameters on the discrimination abilities are also discussed. PMID:24958291

  14. [Juvenile idiopathic epiretinal membrane].

    Science.gov (United States)

    Kontopoulou, K; Krause, S; Fili, S; Hayvazov, S; Schilling, H; Kohlhaas, M

    2016-07-01

    Idiopathic epiretinal membrane (iERM) is very rare in adolescent patients. The pathogenesis remains unclear although the role of hyalocytes is of major importance. The clinical features in young patients are different from those in older patients. We describe a case of iERM in a 15-year-old girl who presented with metamorphopsia of the right eye. This case report presents the basis for the decision for surgical treatment as well as the clinical features at follow-up examination 9 months after surgery.

  15. Oxygen Transport Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay

    2008-08-30

    The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the

  16. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana; Thomas W. Eagar; Harold R. Larson; Raymundo Arroyave; X.-D Zhou; Y.-W. Shin; H.U. Anderson; Nigel Browning; Alan Jacobson; C.A. Mims

    2003-11-01

    The present quarterly report describes some of the initial studies on newer compositions and also includes newer approaches to address various materials issues such as in metal-ceramic sealing. The current quarter's research has also focused on developing a comprehensive reliability model for predicting the structural behavior of the membranes in realistic conditions. In parallel to industry provided compositions, models membranes have been evaluated in varying environment. Of importance is the behavior of flaws and generation of new flaws aiding in fracture. Fracture mechanics parameters such as crack tip stresses are generated to characterize the influence of environment. Room temperature slow crack growth studies have also been initiated in industry provided compositions. The electrical conductivity and defect chemistry of an A site deficient compound (La{sub 0.55}Sr{sub 0.35}FeO{sub 3}) was studied. A higher conductivity was observed for La{sub 0.55}Sr{sub 0.35}FeO{sub 3} than that of La{sub 0.60}Sr{sub 0.40}FeO{sub 3} and La{sub 0.80}Sr{sub 0.20}FeO{sub 3}. Defect chemistry analysis showed that it was primarily contributed by a higher carrier concentration in La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. Moreover, the ability for oxygen vacancy generation is much higher in La{sub 0.55}Sr{sub 0.35}FeO{sub 3} as well, which indicates a lower bonding strength between Fe-O and a possible higher catalytic activity for La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. The program continued to investigate the thermodynamic properties (stability and phase separation behavior) and total conductivity of prototype membrane materials. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previous report listed initial measurements on a sample of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-x} prepared in-house by Praxair. Subsequently, a second sample of powder from a larger batch of sample were characterized and compared

  17. Gas separations using inorganic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Egan, B.Z.; Singh, S.P.N. (Oak Ridge National Lab., TN (United States)); Fain, D.E.; Roettger, G.E.; White, D.E. (Oak Ridge K-25 Site, TN (United States))

    1992-04-01

    This report summarizes the results from a research and development program to develop, fabricate, and evaluate inorganic membranes for separating gases at high temperatures and pressures in hostile process environments encountered in fossil energy conversion processes such as coal gasification. The primary emphasis of the research was on the separation and recovery of hydrogen from synthesis gas. Major aspects of the program included assessment of the worldwide research and development activity related to gas separations using inorganic membranes, identification and selection of candidate membrane materials, fabrication and characterization of membranes using porous membrane technology developed at the Oak Ridge K-25 Site, and evaluation of the separations capability of the fabricated membranes in terms of permeabilities and fluxes of gases.

  18. Membrane fouling and wetting in membrane distillation and their mitigation by novel membranes with special wettability.

    Science.gov (United States)

    Wang, Zhangxin; Lin, Shihong

    2017-04-01

    Membrane distillation (MD) has been identified as a promising technology to desalinate the hypersaline wastewaters from fracking and other industries. However, conventional hydrophobic MD membranes are highly susceptible to fouling and/or wetting by the hydrophobic and/or amphiphilic constituents in these wastewaters of complex compositions. This study systematically investigates the impact of the surface wetting properties on the membrane wetting and/or fouling behaviors in MD. Specifically, we compare the wetting and fouling resistance of three types of membranes of different wetting properties, including hydrophobic and omniphobic membranes as well as composite membranes with a hydrophobic substrate and a superhydrophilic top surface. We challenged the MD membranes with hypersaline feed solutions that contained a relatively high concentration of crude oil with and without added synthetic surfactants, Triton X-100. We found that the composite membranes with superhydrophilic top surface were robustly resistant to oil fouling in the absence of Triton X-100, but were subject to pore wetting in the presence of Triton X-100. On the other hand, the omniphobic membranes were easily fouled by oil-in-water emulsion without Triton X-100, but successfully sustained stable MD performance with Triton X-100 stabilized oil-in-water emulsion as the feed solution. In contrast, the conventional hydrophobic membranes failed readily regardless whether Triton X-100 was present, although via different mechanisms. These findings are corroborated by contact angle measures as well as oil-probe force spectroscopy. This study provides a holistic picture regarding how a hydrophobic membrane fails in MD and how we can leverage membranes with special wettability to prevent membrane failure in MD operations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Cell invasion through basement membrane

    OpenAIRE

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recent...

  20. Inorganic membranes and catalytic reactors

    OpenAIRE

    Rangel, Maria do Carmo

    1997-01-01

    Membrane reactors are reviewed with emphasis in their applications in catalysis field. The basic principles of these systems are presented as well as a historical development. The several kinds of catalytic membranes and their preparations are discussed including the problems, needs and challenges to be solved in order to use these reactors in commercial processes. Some applications of inorganic membrane reactors are also shown. It was concluded that these systems have a great potential for i...

  1. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  2. Conical Nanopore PC Membranes

    International Nuclear Information System (INIS)

    Clochard, M. C.

    2006-01-01

    Template synthesis can be considered an alternative to conventional lithography methods. It is one way of providing a panel of nanoscale metallic wires, tubes or organic polymeric devices. Our interest is focused on track-etched membranes produced from swift heavy ions bombardment of polymer films. In comparison with self-assembly of block copolymers, this bottom-up approach has the advantage of being economic, it is not time-consuming and it allows track formation of diverse geometries. Tailoring of the conical nanopore tip opening would have a tremendous impact on sensing domain, as well as on fundamental understanding of perpendicular giant magneto Resistance properties observed in metallic multilayered cylindrical nanowires. By combining low-energy heavy ion beam radiation effects with asymmetric etching, the etching temperature and time can be tuned to prepare conical nanopores of controlled geometry from 0.5 to 1μm at the base to a few nanometers at the top. Asymmetric etching onto PC films was pH-monitored at various temperatures in the range of 65 degree to 80 degree. Fluence impact onto track etch pores was also investigated. The pore shape characterization was achieved by electronic microscopy measurements on membrane surfaces and on electrodeposited nanowires. We have also observed a difference in the conical shape of replicated nanowires. Some showed sting shapes and others displayed shell shapes depending on whether a neutralizing agent was used during etching or not

  3. Characterization of Polymeric Nanofiltration Membranes

    Directory of Open Access Journals (Sweden)

    Simoncic, B.

    2007-11-01

    Full Text Available As membrane processes are increasingly used in industrial applications, there is a growing interest in methods of membrane characterization. Traditional membrane characteristics, such as cut-off value and pore size distribution, are being supplemented by membrane surface characteristics, such as charge density or zeta potential and hydrophobicity. This study, therefore, characterizes the three different polymeric membranes used (NFT-50, DL and DK. The molecular mass cut-off (MMCO value was determined using a set of reference solutes within the molecular range 150-600 Da, whereas streaming potential measurements enabled quantification of the surface charge characteristics. Hydrophobicity was studied using contact angle measurements. The results indicated that even though all three membranes had very similar layer compositions which consisted of poly(piperazneamide, as top layers they showed different values of measured quantitive. The NFT-50 membrane had the lowest MMCO value and the most hydrophilic membrane surface, followed by DK and DL. Membrane fouling as measured by flux reduction was determined by streaming potential measurements and accompanied by a positive change in zeta potential.

  4. Track membranes, production, properties, applications

    International Nuclear Information System (INIS)

    Oganesjan, Yu.Ts.

    1994-01-01

    The problems of producing track membranes on heavy ion beams of the Flerov Laboratory are considered. The parameters of the running accelerators and equipment for the irradiation of polymer foils are presented. The process of production of track membranes based on different polymeric materials and various applications of the membranes are described. Special attention is given to the principally new applications and devices developed at the Laboratory. This report presents the results obtained by a big group of scientists and engineers working in the field of elaboration, investigation and application of track membranes (author). 21 refs, 20 figs, 1 tab

  5. Amniotic membrane for burn trauma

    International Nuclear Information System (INIS)

    Jamaluddin Zainol; Hasim Mohammad

    1999-01-01

    Amniotic membranes are derived from human placentae at birth. They have two layers mainly the amniotic and the chorionic surfaces which are separated by a thin layer of connective tissues. The two layers are separated during procurement, the placenta and the chorionic side are discarded and the amnion membranes are then further processed. Amnion membranes are normally procured from placentae which are normally free of infections, i.e; the mothers are antenatally screened for sexually transmitted diseases or AlDs related diseases. Intrapartum the mother should not be having chorioamnionitis or jaundice. Sometimes the amniotic membranes are acquired from fresh elective caeserian sections. After processing, the amniotic membranes are packed in two layers of polypropylene and radiated with cobalt 60 at a dose of about 25 kGy. The amniotic membranes are clinically used to cover burn surfaces especially effective for superficial or partial thickness burns. The thin membranes adhered well to the trauma areas and peeled off automatically by the second week. No change of dressing were necessary during these times because of the close adherence, there were less chance of external contamination or infections of these wounds. Due to their flexibility they are very useful to cover difference contours of the human body for example the face, body, elbows or knees. However our experience revealed that amniotic membranes are not useful for third degree bums because the membranes dissolves by the enzymes present in the wounds

  6. Proton exchange membrane fuel cells

    CERN Document Server

    Qi, Zhigang

    2013-01-01

    Preface Proton Exchange Membrane Fuel CellsFuel CellsTypes of Fuel CellsAdvantages of Fuel CellsProton Exchange Membrane Fuel CellsMembraneCatalystCatalyst LayerGas Diffusion MediumMicroporous LayerMembrane Electrode AssemblyPlateSingle CellStackSystemCell Voltage Monitoring Module (CVM)Fuel Supply Module (FSM)Air Supply Module (ASM)Exhaust Management Module (EMM)Heat Management Module (HMM)Water Management Module (WMM)Internal Power Supply Module (IPM)Power Conditioning Module (PCM)Communications Module (COM)Controls Module (CM)SummaryThermodynamics and KineticsTheoretical EfficiencyVoltagePo

  7. Challenges in commercializing biomimetic membranes

    DEFF Research Database (Denmark)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine Elkjær

    2015-01-01

    The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One...... of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments...... relevant for biomimetic aquaporin membranes....

  8. Permeability testing of biomaterial membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dreesmann, L; Hajosch, R; Nuernberger, J Vaz; Schlosshauer, B [NMI Natural and Medical Sciences Institute at University Tuebingen, Markwiesenstr. 55, D-72770 Reutlingen (Germany); Ahlers, M [GELITA AG, Gammelsbacher Str. 2, D-69412 Eberbach (Germany)], E-mail: schlosshauer@nmi.de

    2008-09-01

    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation.

  9. Permeability testing of biomaterial membranes

    International Nuclear Information System (INIS)

    Dreesmann, L; Hajosch, R; Nuernberger, J Vaz; Schlosshauer, B; Ahlers, M

    2008-01-01

    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation

  10. Composite membrane with integral rim

    Science.gov (United States)

    Routkevitch, Dmitri; Polyakov, Oleg G

    2015-01-27

    Composite membranes that are adapted for separation, purification, filtration, analysis, reaction and sensing. The composite membranes can include a porous support structure having elongate pore channels extending through the support structure. The composite membrane also includes an active layer comprising an active layer material, where the active layer material is completely disposed within the pore channels between the surfaces of the support structure. The active layer is intimately integrated within the support structure, thus enabling great robustness, reliability, resistance to mechanical stress and thermal cycling, and high selectivity. Methods for the fabrication of composite membranes are also provided.

  11. Comparison and analysis of membrane fouling between flocculent sludge membrane bioreactor and granular sludge membrane bioreactor.

    Directory of Open Access Journals (Sweden)

    Wang Jing-Feng

    Full Text Available The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs, two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates.

  12. Degradation of Polypropylene Membranes Applied in Membrane Distillation Crystallizer

    Directory of Open Access Journals (Sweden)

    Marek Gryta

    2016-03-01

    Full Text Available The studies on the resistance to degradation of capillary polypropylene membranes assembled in a membrane crystallizer were performed. The supersaturation state of salt was achieved by evaporation of water from the NaCl saturated solutions using membrane distillation process. A high feed temperature (363 K was used in order to enhance the degradation effects and to shorten the test times. Salt crystallization was carried out by the application of batch or fluidized bed crystallizer. A significant membrane scaling was observed regardless of the method of realized crystallization. The SEM-EDS, DSC, and FTIR methods were used for investigations of polypropylene degradation. The salt crystallization onto the membrane surface accelerated polypropylene degradation. Due to a polymer degradation, the presence of carbonyl groups on the membranes’ surface was identified. Besides the changes in the chemical structure a significant mechanical damage of the membranes, mainly caused by the internal scaling, was also found. As a result, the membranes were severely damaged after 150 h of process operation. A high level of salt rejection was maintained despite damage to the external membrane surface.

  13. Effect of temperature shocks on membrane fouling in membrane bioreactors

    NARCIS (Netherlands)

    Brink, van den P.; Satpradit, O.A.; Bentem, van A.; Zwijnenburg, A.; Temmink, B.G.; Loosdrecht, M.C.M.

    2011-01-01

    Temperature is known to influence the biological performance of conventional activated sludge systems. In membrane bioreactors (MBRs), temperature not only affects the bioconversion process but is also shown to have an effect on the membrane performance. Four phenomena are generally reported to

  14. Taming Membranes : Functional Immobilization of Biological Membranes in Hydrogels

    NARCIS (Netherlands)

    Kusters, Ilja; Mukherjee, Nobina; de Jong, Menno R.; Tans, Sander; Kocer, Armagan; Driessen, Arnold J. M.

    2011-01-01

    Single molecule studies on membrane proteins embedded in their native environment are hampered by the intrinsic difficulty of immobilizing elastic and sensitive biological membranes without interfering with protein activity. Here, we present hydrogels composed of nano-scaled fibers as a generally

  15. Operation of staged membrane oxidation reactor systems

    Science.gov (United States)

    Repasky, John Michael

    2012-10-16

    A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

  16. Radiation-induced damage of membranes

    International Nuclear Information System (INIS)

    Yonei, Shuji

    1977-01-01

    An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

  17. High Flux Metallic Membranes for Hydrogen Recovery and Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buxbaum, Robert

    2010-06-30

    We made and tested over 250 new alloys for use as lower cost, higher flux hydrogen extraction membrane materials. Most of these were intermetallic, or contained significant intermetallic content, particularly based on B2 alloy compositions with at least one refractory component; B2 intermetallics resemble BCC alloys, in structure, but the atoms have relatively fixed positions, with one atom at the corners of the cube, the other at the centers. The target materals we were looking for would contain little or no expensive elements, no strongly toxic or radioactive elements, would have high flux to hydrogen, while being fabricable, brazable, and relatively immune to hydrogen embrittlement and corrosion in operation. The best combination of properties of the membrane materials we developed was, in my opinion, a Pd-coated membrane consisting of V -9 atomic % Pd. This material was relatively cheap, had 5 times the flux of Pd under the same pressure differential, was reasonably easy to fabricate and braze, and not bad in terms of embrittlement. Based on all these factors we project, about 1/3 the cost of Pd, on an area basis for a membrane designed to last 20 years, or 1/15 the cost on a flux basis. Alternatives to this membrane replaced significant fractions of the Pd with Ni and or Co. The cost for these membranes was lower, but so was the flux. We produced successful brazed products from the membrane materials, and made them into flat sheets. We tested, unsuccessfully, several means of fabricating thematerials into tubes, and eventually built a membrane reactor using a new, flat-plate design: a disc and doughnut arrangement, a design that seems well- suited to clean hydrogen production from coal. The membranes and reactor were tested successfully at Western Research. A larger equipment company (Chart Industries) produced similar results using a different flat-plate reactor design. Cost projections of the membrane are shown to be attractive.

  18. Estudo dos fatores impregnação e secagem nas características de glóbulos utilizados em homeopatia Study of impregnation and drying factors in the characteristics of globules used in homeopathy

    Directory of Open Access Journals (Sweden)

    Eliana E. Diehl

    2008-03-01

    Full Text Available Glóbulos são uma das formas farmacêuticas mais dispensadas em farmácias homeopáticas no Brasil. Este trabalho teve como objetivo comparar técnicas de impregnação especificadas na Farmacopéia Homeopática Brasileira 2ª Edição e Manual de Normas Técnicas para Farmácia Homeopática 3ª Edição e na prática em farmácias homeopáticas do município de Florianópolis, Santa Catarina, Brasil. As variáveis de formulação percentual de insumo ativo (3 e 10% e tipo de impregnação (simples e tríplice e a variável de processo temperatura de secagem (20 e 50ºC foram analisadas através de planejamento fatorial 2³. As respostas estudadas foram o peso antes e após impregnação e o tempo de desagregação. Os resultados mostraram maior diferença de peso com impregnação a 10 % e secagem a 50ºC, independente do tipo de impregnação. O tempo de desagregação não foi influenciado pelas variáveis em estudo (p Globules are one of the most dosage forms dispensed in homeopathic pharmacies in Brazil. This work aimed at comparing different impregnation techniques specified in the Brazilian Homeopathic Pharmacopoeia 2 Edition and Manual of Technical Norms for Homeopathic Pharmacy 3 Edition and the practical in homeopathic pharmacies in the city of Florianópolis, state of Santa Catarina, Brazil. The formulations variables percent active raw material (3 and 10%, impregnation type (simple and triple and the process variable drying temperature (20 and 50ºC were analyzed through a factorial design 2³. The studied answers were the weight before and after the impregnation and time of disaggregation. The results show a larger weight difference with the 10% impregnation and the drying of 50ºC, regardless of the impregnation type. The time of disaggregation wasn't influenced by the studied variables (p < 0.05. The best homogeneity was verified for the formulation with triple impregnation at 10%.

  19. Membrane controlled anaerobic digestion

    Science.gov (United States)

    Omstead, D. R.

    In response to general shortages of energy, examination of the anaerboic digestion process as a potential source of a combustible, methane-rich fuel has intensified in recent years. It has been suggested that orgaic intermediates (such as fatty acids), produced during digestion, might also be recovered for use as chemical feedstocks. This investigation has been concerned with combining ultrafiltration separation techniques with anaerobic digestion for the development of a process in which the total production of acetic acid (the most valuable intermediate in anaerobic digestion) and methane are optimized. Enrichment cultures, able to utilize glucose as a sole carbon source, were adapted from sewage digesting cultures using conventional techniques. An ultrafiltration system was constructed and coupled to an anaerobic digester culture vessel which contained the glucose enrichment. The membrane controlled anaerobic digester appears to show promise as a means of producing high rates of both methane gas and acetic acid.

  20. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; T. Nithyanantham

    2006-12-31

    Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought to be correlated with the physiochemical features of the two-phases. We have reviewed the electrical conductivity data and stoichiometry data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} some of which was reported previously. Electrical conductivity data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCrF) were obtained in the temperature range, 752 {approx} 1055 C and in the pO{sub 2} range, 10{sup -18} {approx} 0.5 atm. The slope of the plot of log {sigma} vs

  1. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; T. Nithyanantham

    2006-06-30

    A non-agglomerated and nanocrystalline-sized powder was successfully produced using ethylene glycol nitrate methods. The LSFT powder prepared using this method exhibits well dispersed and nano-sized particles about 100-200 nm. The density of LSFT sintered at 1300 C was about 90% of the theoretical density at which is 100 C less than that of the previous LSFT which was sintered at 1400 C. The sample sintered at 1400 C exhibited the evidence of a liquid phase at the grain boundaries and 2nd phase formation which probably caused low mechanical stability. The electrical conductivity and Seebeck coefficient were measured as a function of temperature. The LSFT-CGO specimens were cut from the as sintered bars and used for the evaluation of Mechanical Properties after polishing. The effect of strain rate on the flexural strength of the LSFT-CGO test specimens was studied. Three strain rates 6, 60 and 600 {micro}m/ min were chosen for this study. It is observed from the results that with increasing cross head speed the membrane takes higher loads to fail. A reduction in the strength of the membrane was observed at 1000 C in N{sub 2}. Two different routes were investigated to synthesis GDC using either formate or carbonate precursors. The precursor and CGO particle morphologies were examined by scanning electron microscopy. The thermal decomposition behaviors of Ce(Gd)(HCOO){sub 3} and Ce(Gd)(CO{sub 3})(OH) were determined by thermogravimetric analysis (TGA) at a rate of 3 C/min in air. The X-ray powder diffraction patterns of the precursor and CGO were collected and nitrogen adsorption isotherms were measured. Conductivity measurements were made by AC impedance spectroscopy on sintered disks in air using platinum electrodes.

  2. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana

    2003-08-07

    In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over the pressure range studied. From the stoichiometry a lower limit of 2.6 corresponding to the reduction of all Fe{sup 4+} to Fe{sup 3+} and no reduction of Cr{sup 3+} is expected.

  3. Electro-catalytic membrane reactors and the development of bipolar membrane technology

    NARCIS (Netherlands)

    Balster, J.H.; Stamatialis, Dimitrios; Wessling, Matthias

    2004-01-01

    Membrane reactors are currently under extensive research and development. Hardly any concept, however, is realized yet in practice. Frequently, forgotten as membrane reactors are electro-catalytic membrane reactors where electrodes perform chemical conversations and membranes separate the locations

  4. Biogenesis of plasma membrane cholesterol

    International Nuclear Information System (INIS)

    Lange, Y.

    1986-01-01

    A striking feature of the molecular organization of eukaryotic cells is the singular enrichment of their plasma membranes in sterols. The authors studies are directed at elucidating the mechanisms underlying this inhomogeneous disposition. Cholesterol oxidase catalyzes the oxidation of plasma membrane cholesterol in intact cells, leaving intracellular cholesterol pools untouched. With this technique, the plasma membrane was shown to contain 95% of the unesterified cholesterol of cultured human fibroblasts. Cholesterol synthesized from [ 3 H] acetate moved to the plasma membrane with a half-time of 1 h at 37 0 C. They used equilibrium gradient centrifugation of homogenates of biosynthetically labeled, cholesterol oxidase treated cells to examine the distribution of newly synthesized sterols among intracellular pools. Surprisingly, lanosterol, a major precursor of cholesterol, and intracellular cholesterol both peaked at much lower buoyant density than did 3-hydroxy-3-methylglutaryl-CoA reductase. This suggests that cholesterol biosynthesis is not taken to completion in the endoplasmic reticulum. The cholesterol in the buoyant fraction eventually moved to the plasma membrane. Digitonin treatment increased the density of the newly synthesized cholesterol fractions, indicating that nascent cholesterol in transit is associated with cholesterol-rich membranes. The authors are testing the hypothesis that the pathway of cholesterol biosynthesis is spatially organized in various intracellular membranes such that the sequence of biosynthetic steps both concentrates the sterol and conveys it to the plasma membrane

  5. Modelling of proteins in membranes

    DEFF Research Database (Denmark)

    Sperotto, Maria Maddalena; May, S.; Baumgaertner, A.

    2006-01-01

    This review describes some recent theories and simulations of mesoscopic and microscopic models of lipid membranes with embedded or attached proteins. We summarize results supporting our understanding of phenomena for which the activities of proteins in membranes are expected to be significantly...

  6. Fabrication of green polymeric membranes

    KAUST Repository

    Kim, Dooli

    2017-06-16

    Provided herein are methods of fabricating membranes using polymers with functionalized groups such as sulfone (e.g., PSf and PES), ether (e.g., PES), acrylonitrile (e.g., PAN), fluoride(e.g., pvdf and other fluoropolymers), and imide (e.g., extem) and ionic liquids. Also provided are membranes made by the provided methods.

  7. Inorganic membranes for pervaporation technology

    NARCIS (Netherlands)

    Sekulic, J.; Luiten-Olieman, Maria W.J.; Luiten, M.W.J.; ten Elshof, Johan E.; Benes, Nieck Edwin; Keizer, Klaas

    2002-01-01

    The aim of this work is the development of inorganic membranes that will enable broad application of pervaporation/vapour permeation technology in the chemical industry. This can be achieved by improvement of the existing microporous membranes and the development of new types with enhanced

  8. Mathematical modelling of membrane separation

    DEFF Research Database (Denmark)

    Vinther, Frank

    This thesis concerns mathematical modelling of membrane separation. The thesis consists of introductory theory on membrane separation, equations of motion, and properties of dextran, which will be the solute species throughout the thesis. Furthermore, the thesis consist of three separate mathemat......This thesis concerns mathematical modelling of membrane separation. The thesis consists of introductory theory on membrane separation, equations of motion, and properties of dextran, which will be the solute species throughout the thesis. Furthermore, the thesis consist of three separate...... mathematical models, each with a different approach to membrane separation. The first model is a statistical model investigating the interplay between solute shape and the probability of entering the membrane. More specific the transition of solute particles from being spherical to becoming more elongated...... and the rejection coefficient. The second model is a stationary model for the flux of solvent and solute in a hollow fibre membrane. In the model we solve the time independent equations for transport of solvent and solute within the hollow fibre. Furthermore, the flux of solute and solvent through the membrane...

  9. Membranes and Films from Polymers.

    Science.gov (United States)

    Blumberg, Avrom A.

    1986-01-01

    Provides background information on polymeric films and membranes including production methods, special industrial and medical applications, laboratory preparation, and an experimental investigation of a porous cellulose acetate membrane. Presents a demonstration to distinguish between high- and low-density polyethylene. (JM)

  10. Nitrocellulose Membrane: The New Canvas.

    Science.gov (United States)

    Kurien, Jasmin R; Kurien, Bianca A

    2015-01-01

    The use of nitrocellulose membranes for invisible ink-messaging or marking for orientation purposes has been carried out with diluted alkaline phosphatase, followed by development with nitro blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate and chemiluminescence detection systems. Here, we show that nitrocellulose membrane can serve as a canvas for art using alkaline phosphatase and NBT/BCIP detection method.

  11. Gas separation membranes current status

    International Nuclear Information System (INIS)

    Puri, S.P.

    1996-01-01

    Membrane-based gas separation systems are now widely accepted and employed as unit operation in industrial gas, chemical and allied industries. Following their successful commercialization in the late Seventies to recover hydrogen from ammonia purge gas streams, membrane-based systems have gained acceptance in a wide variety of applications

  12. Membranes for Enhanced Emulsification Processes

    NARCIS (Netherlands)

    Güell, Carme; Ferrando, Montse; Schroen, C.G.P.H.

    2016-01-01

    The use of membrane technology for the production of single and double emulsions has been proven feasible for a wide range of systems. The low energy requirements and mild process conditions (shear stress and temperature) of membrane emulsification (ME) compared to conventional processes makes it of

  13. Hydrogen Selective Exfoliated Zeolite Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tsapatsis, Michael [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Daoutidis, Prodromos [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Elyassi, Bahman [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Lima, Fernando [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Iyer, Aparna [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Agrawal, Kumar [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Sabnis, Sanket [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science

    2015-04-06

    The objective of this project was to develop and evaluate an innovative membrane technology at process conditions that would be representative of Integrated Gasification Combined Cycle (IGCC) advanced power generation with pre-combustion capture of carbon dioxide (CO2). This research focused on hydrogen (H2)-selective zeolite membranes that could be utilized to separate conditioned syngas into H2-rich and CO2-rich components. Both experiments and process design and optimization calculations were performed to evaluate the concept of ultra-thin membranes made from zeolites nanosheets. In this work, efforts in the laboratory were made to tackle two fundamental challenges in application of zeolite membranes in harsh industrial environments, namely, membrane thickness and membrane stability. Conventional zeolite membranes have thicknesses in the micron range, limiting their performance. In this research, we developed a method for fabrication of ultimately thin zeolite membranes based on zeolite nanosheets. A range of layered zeolites (MWW, RWR, NSI structure types) suitable for hydrogen separation was successfully exfoliated to their constituent nanosheets. Further, membranes were made from one of these zeolites, MWW, to demonstrate the potential of this group of materials. Moreover, long-term steam stability of these zeolites (up to 6 months) was investigated in high concentrations of steam (35 mol% and 95 mole%), high pressure (10 barg), and high temperatures (350 °C and 600 °C) relevant to conditions of water-gas-shift and steam methane reforming reactions. It was found that certain nanosheets are stable, and that stability depends on the concentration of structural defects. Additionally, models that represent a water-gas-shift (WGS) membrane reactor equipped with the zeolite membrane were developed for systems studies. These studies had the aim of analyzing the effect of the membrane reactor integration into IGCC plants

  14. Staged membrane oxidation reactor system

    Science.gov (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  15. Drug-model membrane interactions

    International Nuclear Information System (INIS)

    Deniz, Usha K.

    1994-01-01

    In the present day world, drugs play a very important role in medicine and it is necessary to understand their mode of action at the molecular level, in order to optimise their use. Studies of drug-biomembrane interactions are essential for gaining such as understanding. However, it would be prohibitively difficult to carry out such studies, since biomembranes are highly complex systems. Hence, model membranes (made up of these lipids which are important components of biomembranes) of varying degrees of complexity are used to investigate drug-membrane interactions. Bio- as well as model-membranes undergo a chain melting transition when heated, the chains being in a disordered state above the transition point, T CM . This transition is of physiological importance since biomembranes select their components such that T CM is less than the ambient temperature but not very much so, so that membrane flexibility is ensured and porosity, avoided. The influence of drugs on the transition gives valuable clues about various parameters such as the location of the drug in the membrane. Deep insights into drug-membrane interactions are obtained by observing the effect of drugs on membrane structure and the mobilities of the various groups in lipids, near T CM . Investigation of such changes have been carried out with several drugs, using techniques such as DSC, XRD and NMR. The results indicate that the drug-membrane interaction not only depends on the nature of drug and lipids but also on the form of the model membrane - stacked bilayer or vesicles. The light that these results shed on the nature of drug-membrane interactions is discussed. (author). 13 refs., 13 figs., 1 tab

  16. Nanoporous Membrane Technologies for Pathogen Collection, Separation, and Detection

    National Research Council Canada - National Science Library

    Lee, Sang W; Shang, Hao; Lee, Gil U; Griffin, Matthew T; Fulton, Jack

    2003-01-01

    Partial contents: Nanoporous Membranes, Membrane Chemistries, Characterization of Membrane Chemistries,Protein Fouling, Collector,Gas and Liquid Permeabilities, Membrane Permeabilities in the Presence of Water...

  17. Membranes and theoretical modeling of membrane distillation: a review.

    Science.gov (United States)

    Khayet, Mohamed

    2011-05-11

    Membrane distillation (MD) is one of the non-isothermal membrane separation processes used in various applications such desalination, environmental/waste cleanup, food, etc. It is known since 1963 and is still being developed at laboratory stage for different purposes and not fully implemented in industry. An abrupt increase in the number of papers on MD membrane engineering (i.e. design, fabrication and testing in MD) is seen since only 6 years ago. The present paper offers a comprehensive MD state-of-the-art review covering a wide range of commercial membranes, MD membrane engineering, their MD performance, transport mechanisms, experimental and theoretical modeling of different MD configurations as well as recent developments in MD. Improved MD membranes with specific morphology, micro- and nano-structures are highly demanded. Membranes with different pore sizes, porosities, thicknesses and materials as well as novel structures are required in order to carry out systematic MD studies for better understanding mass transport in different MD configurations, thereby improving the MD performance and looking for MD industrialization. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Managing a Coastal Bluegum (Eucalyptus globules) forest

    Science.gov (United States)

    Ralph S. Osterling

    1983-01-01

    Eucalyptus was thought to be a replacement to oak and other hardwoods for many products. Thousands of acres have been planted and now are in need of management. Management techniques are discussed in context with a coastal stand of approximately 300 acres of mixed aged bluegum. Potential markets are explored.

  19. Electrospun superhydrophobic membranes with unique structures for membrane distillation.

    Science.gov (United States)

    Liao, Yuan; Loh, Chun-Heng; Wang, Rong; Fane, Anthony G

    2014-09-24

    With modest temperature demand, low operating pressure, and high solute rejection, membrane distillation (MD) is an attractive option for desalination, waste treatment, and food and pharmaceutical processing. However, large-scale practical applications of MD are still hindered by the absence of effective membranes with high hydrophobicity, high porosity, and adequate mechanical strength, which are important properties for MD permeation fluxes, stable long-term performance, and effective packing in modules without damage. This study describes novel design strategies for highly robust superhydrophobic dual-layer membranes for MD via electrospinning. One of the newly developed membranes comprises a durable and ultrathin 3-dimensional (3D) superhydrophobic skin and porous nanofibrous support whereas another was fabricated by electrospinning 3D superhydrophobic layers on a nonwoven support. These membranes exhibit superhydrophobicity toward distilled water, salty water, oil-in-water emulsion, and beverages, which enables them to be used not only for desalination but also for other processes. The superhydrophobic dual-layer membrane #3S-N with nanofibrous support has a competitive permeation flux of 24.6 ± 1.2 kg m(-2) h(-1) in MD (feed and permeate temperate were set as 333 and 293 K, respectively) due to the higher porosity of the nanofibrous scaffold. Meanwhile, the membranes with the nonwoven support exhibit greater mechanical strength due to this support combined with better long-term performance because of the thicker 3D superhydrophobic layers. The morphology, pore size, porosity, mechanical properties, and liquid enter pressure of water of these superhydrophobic composite membranes with two different structures are reported and compared with commercial polyvinylidene fluoride membranes.

  20. Universal Behavior of Membranes with Sterols

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Rowat, Amy C.; Brief, E.

    2006-01-01

    ) is obtained from deuterium nuclear magnetic resonance. We compare these results, along with data for membrane-bending rigidity, to explore the relationship between membrane hydrophobic thickness and elastic properties. Together, such diverse approaches demonstrate that membrane properties are affected...

  1. Membrane species mobility under in-lipid-membrane forced convection.

    Science.gov (United States)

    Hu, Shu-Kai; Huang, Ling-Ting; Chao, Ling

    2016-08-17

    Processing and managing cell membrane proteins for characterization while maintaining their intact structure is challenging. Hydrodynamic flow has been used to transport membrane species in supported lipid bilayers (SLBs) where the hydrophobic cores of the membrane species can be protected during processing. However, the forced convection mechanism of species embedded in lipid bilayers is still unclear. Developing a controlled SLB platform with a practical model to predict the membrane species mobility in the platform under in-lipid-membrane forced convection is imperative to ensure the practical applicability of SLBs in processing and managing membrane species with various geometrical properties. The mobility of membrane species is affected by the driving force from the aqueous environment in addition to the frictions from the lipid bilayer, in which both lipid leaflets may exhibit different speeds relative to that of the moving species. In this study, we developed a model, based on the applied driving force and the possible frictional resistances that the membrane species encounter, to predict how the mobility under in-lipid-membrane forced convection is influenced by the sizes of the species' hydrophilic portion in the aqueous environment and the hydrophobic portion embedded in the membrane. In addition, we used a microfluidic device for controlling the flow to arrange the lipid membrane and the tested membrane species in the desirable locations in order to obtain a SLB platform which can provide clear mobility responses of the species without disturbance from the species dispersion effect. The model predictions were consistent with the experimental observations, with the sliding friction coefficient between the upper leaflet and the hydrophilic portion of the species as the only regressed parameter. The result suggests that not only the lateral drag frictions from the lipid layers but also the sliding frictions between the species and the lipid layer planes

  2. Artificial membranes for membrane protein purification, functionality and structure studies.

    Science.gov (United States)

    Parmar, Mayuriben J; Lousa, Carine De Marcos; Muench, Stephen P; Goldman, Adrian; Postis, Vincent L G

    2016-06-15

    Membrane proteins represent one of the most important targets for pharmaceutical companies. Unfortunately, technical limitations have long been a major hindrance in our understanding of the function and structure of such proteins. Recent years have seen the refinement of classical approaches and the emergence of new technologies that have resulted in a significant step forward in the field of membrane protein research. This review summarizes some of the current techniques used for studying membrane proteins, with overall advantages and drawbacks for each method. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  3. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-10-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, Moessbauer spectroscopy was used to study the local environmentals of LSFT with various level of oxygen deficiency. Ionic valence state, magnetic interaction and influence of Ti on superexchange are discussed Stable crack growth studies on Dense OTM bars provided by Praxair were done at elevated temperature, pressure and elevated conditions. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. The initial measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Neutron diffraction measurements of the same composition are in agreement with both the stoichiometry and the kinetic behavior observed in coulometric titration measurements. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The COCO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  4. Cell invasion through basement membrane

    Science.gov (United States)

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recently discovered that invadopodia breach basement membrane during anchor cell invasion in C. elegans, a genetically and visually tractable in vivo invasion event. Further, we found that the netrin receptor DCC localizes to the initial site of basement membrane breach and directs invasion through a single gap in the matrix. In this commentary, we examine how the dynamics and structure of AC-invadopodia compare with in vitro invadopodia and how the netrin receptor guides invasion through a single basement membrane breach. We end with a discussion of our surprising result that the anchor cell pushes the basement membrane aside, instead of completely dissolving it through proteolysis, and provide some ideas for how proteases and physical displacement may work together to ensure efficient and robust invasion. PMID:24778942

  5. Membrane bioreactors: present and prospects.

    Science.gov (United States)

    Chang, H N; Furusaki, S

    1991-01-01

    Membrane bioreactors have a very handy in-situ separation capability lacking in other types of bioreactors. Combining various functions of membrane separations and biocatalyst characteristics of enzymes, microbial cells, organelles, animal and plant tissues can generate quite a number of membrane bioreactor systems. The cell retaining property of membranes and selective removal of inhibitory byproducts makes high cell density culture possible and utilizes enzyme catalytic activity better, which leads to high productivity of bioreactors. Enzyme reactions utilizing cofactors and hydrolysis of macromolecules are advantageous in membrane bioreactors. Anaerobic cell culture may be efficiently carried out in membrane cell recycle systems, while aerobic cultures work well in dual hollow fiber reactors. Animal and plant cells have much a better chance of success in membrane reactors because of the protective environment of the reactor and the small oxygen uptake rate of these cells. Industrial use of these reactors are still in its infancy and limited to enzyme and animal tissue culture, but applications will expand as existing problems are resolved.

  6. Membrane manufacture for peptide separations

    KAUST Repository

    Kim, Dooli

    2016-06-07

    Nanostructured polymeric membranes are key tools in biomedical applications such as hemodialysis, protein separations, in the food industry, and drinking water supply from seawater. Despite of the success in different separation processes, membrane manufacture itself is at risk, since the most used solvents are about to be banned in many countries due to environmental and health issues. We propose for the first time the preparation of polyethersulfone membranes based on dissolution in the ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DEP). We obtained a series of membranes tailored for separation of solutes with molecular weight of 30, 5, 1.3, and 1.25 kg mol-1 with respective water permeances of 140, 65, 30 and 20 Lm-2h-1bar-1. We demonstrate their superior efficiency in the separation of complex mixtures of peptides with molecular weights in the range of 800 to 3500 gmol-1. Furthermore, the thermodynamics and kinetics of phase separation leading to the pore formation in the membranes were investigated. The rheology of the solutions and the morphology of the prepared membranes were examed and compared to those of polyethersulfone in organic solvents currently used for membrane manufacture.

  7. Gas Separations using Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Paul KT Liu

    2005-01-13

    This project has been oriented toward the development of a commercially viable ceramic membrane for high temperature gas separations. A technically and commercially viable high temperature gas separation membrane and process has been developed under this project. The lab and field tests have demonstrated the operational stability, both performance and material, of the gas separation thin film, deposited upon the ceramic membrane developed. This performance reliability is built upon the ceramic membrane developed under this project as a substrate for elevated temperature operation. A comprehensive product development approach has been taken to produce an economically viable ceramic substrate, gas selective thin film and the module required to house the innovative membranes for the elevated temperature operation. Field tests have been performed to demonstrate the technical and commercial viability for (i) energy and water recovery from boiler flue gases, and (ii) hydrogen recovery from refinery waste streams using the membrane/module product developed under this project. Active commercializations effort teaming with key industrial OEMs and end users is currently underway for these applications. In addition, the gas separation membrane developed under this project has demonstrated its economical viability for the CO2 removal from subquality natural gas and landfill gas, although performance stability at the elevated temperature remains to be confirmed in the field.

  8. Ultrastructure of Reissner's membrane in the rabbit

    DEFF Research Database (Denmark)

    Qvortrup, K.; Rostgaard, Jørgen; Bretlau, P.

    1994-01-01

    Anatomy, Reissner's membrane, electron microscopy, tubulocisternal endoplasmic reticulum, subsurface cisterns, rabbit......Anatomy, Reissner's membrane, electron microscopy, tubulocisternal endoplasmic reticulum, subsurface cisterns, rabbit...

  9. Isolation of plasma membrane-associated membranes from rat liver.

    Science.gov (United States)

    Suski, Jan M; Lebiedzinska, Magdalena; Wojtala, Aleksandra; Duszynski, Jerzy; Giorgi, Carlotta; Pinton, Paolo; Wieckowski, Mariusz R

    2014-02-01

    Dynamic interplay between intracellular organelles requires a particular functional apposition of membrane structures. The organelles involved come into close contact, but do not fuse, thereby giving rise to notable microdomains; these microdomains allow rapid communication between the organelles. Plasma membrane-associated membranes (PAMs), which are microdomains of the plasma membrane (PM) interacting with the endoplasmic reticulum (ER) and mitochondria, are dynamic structures that mediate transport of proteins, lipids, ions and metabolites. These structures have gained much interest lately owing to their roles in many crucial cellular processes. Here we provide an optimized protocol for the isolation of PAM, PM and ER fractions from rat liver that is based on a series of differential centrifugations, followed by the fractionation of crude PM on a discontinuous sucrose gradient. The procedure requires ∼8-10 h, and it can be easily modified and adapted to other tissues and cell types.

  10. Diffusion of Integral Membrane Proteins in Protein-Rich Membranes

    DEFF Research Database (Denmark)

    Javanainen, Matti; Martinez-Seara, Hector; Metzler, Ralf

    2017-01-01

    -like dependence D ∝ 1/R. We propose that this 1/R law mainly arises due to geometrical factors: smaller proteins are able to avoid confinement effects much better than their larger counterparts. The results highlight that the lateral dynamics in the crowded setting found in native membranes is radically different......The lateral diffusion of embedded proteins along lipid membranes in protein-poor conditions has been successfully described in terms of the Saffman-Delbrück (SD) model, which predicts that the protein diffusion coefficient D is weakly dependent on its radius R as D ∝ ln(1/R). However, instead...... of being protein-poor, native cell membranes are extremely crowded with proteins. On the basis of extensive molecular simulations, we here demonstrate that protein crowding of the membrane at physiological levels leads to deviations from the SD relation and to the emergence of a stronger Stokes...

  11. Effect of membrane polymeric materials on relationship between surface pore size and membrane fouling in membrane bioreactors

    Science.gov (United States)

    Miyoshi, Taro; Yuasa, Kotaku; Ishigami, Toru; Rajabzadeh, Saeid; Kamio, Eiji; Ohmukai, Yoshikage; Saeki, Daisuke; Ni, Jinren; Matsuyama, Hideto

    2015-03-01

    We investigated the effect of different membrane polymeric materials on the relationship between membrane pore size and development of membrane fouling in a membrane bioreactor (MBR). Membranes with different pore sizes were prepared using three different polymeric materials, cellulose acetate butyrate (CAB), polyvinyl butyral (PVB), and polyvinylidene fluoride (PVDF), and the development of membrane fouling in each membrane was evaluated by batch filtration tests using a mixed liquor suspension obtained from a laboratory-scale MBR. The results revealed that the optimal membrane pore size to mitigate membrane fouling differed depending on membrane polymeric material. For PVDF membranes, the degree of membrane fouling decreased as membrane pore size increased. In contrast, CAB membranes with smaller pores had less fouling propensity than those with larger ones. Such difference can be attributed to the difference in major membrane foulants in each membrane; in PVDF, they were small colloids or dissolved organics in which proteins are abundant, and in CAB, microbial flocs. The results obtained in this study strongly suggested that optimum operating conditions of MBRs differ depending on the characteristics of the used membrane.

  12. Development of silica RO membranes

    International Nuclear Information System (INIS)

    Ikeda, Ayumi; Kawamoto, Takashi; Matsuyama, Emi; Utsumi, Keisuke; Nomura, Mikihiro; Sugimoto, Masaki; Yoshikawa, Masato

    2012-01-01

    Silica based membranes have been developed by using a counter diffusion CVD method. Effects of alkyl groups in the silica precursors and deposition temperatures had investigated in order to control pore sizes of the silica membranes. In this study, this type of a silica membrane was applied for RO separation. Effects of silica sources, deposition temperatures and post treatments had been investigated. Tetramethoxysilane (TMOS), Ethyltrimethoxysilane (ETMOS) and Phenyltrimethoxysilane (PhTMOS) were used as silica precursors. A counter diffusion CVD method was carried out for 90 min at 270 - 600degC on γ-alumina capillary substrates (effective length: 50 mm, φ: 4 nm: NOK Co.). O 3 or O 2 was introduced into the inside of the substrate at the O 2 rate of 0.2 L min -1 . Ion beam irradiation was carried out for a post treatment using Os at 490 MeV for 1.0 x 10 10 ions cm -2 or 3.0 x 10 10 ions cm -2 . Single gas permeance was measured by using H 2 , N 2 and SF 6 . RO tests were employed at 3.0 or 5.4 MPa for 100 mg L -1 of feed NaCl solution. First, effects of the silica sources were investigated. The total fluxes increased by increasing N 2 permeance through the silica membrane deposited by ETMOS. The maximum NaCl rejection was 28.2% at 12.2 kg m -2 h -1 of the total flux through the membrane deposited at 270degC. N 2 permeance was 9.6 x 10 -9 mol m -2 s -1 Pa -1 . While, total fluxes through the membrane deposited by using PhTMOS were smaller than those through the ETMOS membranes. The phenyl groups for the PhTMOS membrane must be important for the hydrophobic properties through the membrane. Next, effects of ion beam irradiation were tested for the TMOS membranes. Water is difficult to permeate through the TMOS membranes due to the low N 2 permeance through the membrane (3.1 x 10 -11 mol m -2 s -1 Pa -1 ). N 2 permeance increased to 7.3 x 10 -9 mol m -2 s -1 Pa -1 by the irradiation. Irradiation amounts had little effects on N 2 permeance. However, NaCl rejections

  13. Membrane fluidity in the presence of membrane-binding peptides

    Science.gov (United States)

    Burrola Gabilondo, Beatriz; Losert, Wolfgang; Randazzo, Paul

    2009-03-01

    Arf proteins are GTP-ases that participate in vesicle trafficking inside cells. They are able to interact with membranes through their N-terminus when they are bound to GTP, and they detach from the membrane when GTP is hydrolyzed. The N-terminus of Arf1 (amino acids 2-17) folds into an amphipathic helix that can insert into lipid bilayers. Arf1 is also myristoylated; it has myristic acid, a 14-carbon fatty acid `tail', attached to it. We set out to test the hypothesis that the binding of the myristoylated N-terminus of Arf1 to lipid membranes changes the mechanical properties of the membrane, in ways that myristic acid alone or amphipathic peptides alone do not. We use three reporter molecules embedded in vesicles, whose fluorescence emission spectrum depends on the properties of the environment in which they are found, to measure three distinct aspects of membrane fluidity: Bispyrene is sensitive to lateral motion along the membrane, Prodan's emission gives a measure of the packing of the head groups, and DPH polarization reflects the packing of the hydrophobic tails. We will present effects found for four molecules (myristic acid, myristoylated and non-myristoylated N-terminus of Arf1, and the ALPS domain of KES) in a concentration-dependent manner, and discuss the importance of these results in the vesicle-trafficking picture.

  14. Vacuum membrane distillation of liquid desiccants Utilizing Hollow Fiber Membranes

    KAUST Repository

    Lefers, Ryan

    2018-01-31

    This paper documents the testing of a vacuum membrane distillation system intended for use with liquid desiccants. Liquid desiccants offer the possibility for low-energy, ambient temperature dehumidification. Effective desalination and purification of diluted desiccants outputs two important products: a concentrated desiccant for reuse in dehumidification and fresh water. In this study, vacuum membrane distillation was used in the laboratory to purify diluted liquid desiccants. Calcium chloride and magnesium chloride were the desiccants selected for testing. Desiccant solutions were pumped through the lumens of poly(vinylidene fluoride) (PVDF) hollow fiber membranes at varying feed inlet temperatures, solution velocity rates and vacuum set points during membrane distillation. An average flux of 8 kg m-2 h-1 was obtained using 30 wt% magnesium chloride solution at a temperature of 50 °C while applying vacuum to achieve 25 mbar absolute pressure on the air side of the membrane. The results are promising for the development of a full-scale vacuum membrane distillation process for desiccant solution regeneration and fresh water recovery. In addition, the recovered condensate was of sufficient quality for use in agricultural irrigation or drinking water.

  15. The Role of Ion Exchange Membranes in Membrane Capacitive Deionisation.

    Science.gov (United States)

    Hassanvand, Armineh; Wei, Kajia; Talebi, Sahar; Chen, George Q; Kentish, Sandra E

    2017-09-14

    Ion-exchange membranes (IEMs) are unique in combining the electrochemical properties of ion exchange resins and the permeability of a membrane. They are being used widely to treat industrial effluents, and in seawater and brackish water desalination. Membrane Capacitive Deionisation (MCDI) is an emerging, energy efficient technology for brackish water desalination in which these ion-exchange membranes act as selective gates allowing the transport of counter-ions toward carbon electrodes. This article provides a summary of recent developments in the preparation, characterization, and performance of ion exchange membranes in the MCDI field. In some parts of this review, the most relevant literature in the area of electrodialysis (ED) is also discussed to better elucidate the role of the ion exchange membranes. We conclude that more work is required to better define the desalination performance of the proposed novel materials and cell designs for MCDI in treating a wide range of feed waters. The extent of fouling, the development of cleaning strategies, and further techno-economic studies, will add value to this emerging technique.

  16. Omniphobic Hollow-Fiber Membranes for Vacuum Membrane Distillation.

    Science.gov (United States)

    Lu, Kang Jia; Zuo, Jian; Chang, Jian; Kuan, Hong Nan; Chung, Tai-Shung

    2018-04-03

    Management of produced water from shale gas production is a global challenge. Vacuum membrane distillation (VMD) is considered a promising solution because of its various advantages. However, low-surface-tension species in produced water can easily deposit on the membrane surface and cause severe fouling or wetting problems. To solve the problems, an omniphobic polyvinylidene difluoride (PVDF) hollow-fiber membrane has been developed via silica nanoparticle deposition followed by a Teflon AF 2400 coating in this study. The resultant membrane shows good repellency toward various liquids with different surface tensions and chemistries, including water, ethylene glycol (EG), cooking oil, and ethanol. It also exhibits stable performance in 7 h VMD tests with a feed solution containing up to 0.6 mM of sodium dodecyl sulfate (SDS). In addition, the effects of surface energy and surface morphology as well as nanoparticle size on membrane omniphobicity have been systematically investigated. This work may provide valuable guidance to molecularly design omniphobic VMD membranes for produced water treatment.

  17. Oxygen Transport Ceramic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-05-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C in N{sub 2}. Space group of R3c was found to result in a better refinement and is used in this study. The difference for crystal structure, lattice parameters and local crystal chemistry for LSFT nearly unchanged when gas environment switched from air to N{sub 2}. Stable crack growth studies on Dense OTM bars provided by Praxair were done at room temperature in air. A bridge-compression fixture was fabricated to achieve stable pre-cracks from Vickers indents. Post fracture evaluation indicated stable crack growth from the indent and a regime of fast fracture. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. The thermal and chemical expansion of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were studied at 800 {le} T {le} 1000 C and at {approx} 1 x 10{sup -15} {le} pO{sub 2} {le} 0.21 atm. The thermal expansion coefficient of the sample was calculated from the dilatometric analysis in the temperature range between room temperature and 1200 C in air. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of

  18. Characterization of polyacrylonitrile ultrafiltration membranes

    NARCIS (Netherlands)

    Germic, J.; Germic, J.; Ebert, K.; Ebert, K.; Bouma, R.H.B.; Bouma, R.H.B.; Borneman, Zandrie; Mulder, M.H.V.; Strathmann, H.

    1997-01-01

    Various methods have been used to characterize ultrafiltration membranes, such as gas flux measurements, (field emission) scanning electron microscopy, permporometry and liquid-liquid displacement. Significant differences in the pore size distributions determined from permporometry and liquid-liquid

  19. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    IAS Admin

    hemophagocytic syndrome) and metabolic (diabe- tes) disorders [2, 23, 33]. Mutations in the genes of the basic secretory protein machinery lead to a number of membrane trafficking diseases such as Charcot–Marie–Tooth disease, Cohen.

  20. Layered plasma polymer composite membranes

    Science.gov (United States)

    Babcock, Walter C.

    1994-01-01

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

  1. Membranes in Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Junbo Hou

    2012-07-01

    Full Text Available Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed.

  2. Static and Dynamic Membrane Structures

    Directory of Open Access Journals (Sweden)

    Sergiu Ivanov

    2012-10-01

    Full Text Available While originally P systems were defined to contain multiset rewriting rules, it turned out that considering different types of rules may produce important results, such as increasing the computational power of the rules. This paper focuses on factoring out the concept of a membrane structure out of various P system models with the goal of providing useful formalisations. Both static and dynamic membrane structures are considered.

  3. Gas separation membrane module assembly

    Science.gov (United States)

    Wynn, Nicholas P [Palo Alto, CA; Fulton, Donald A [Fairfield, CA

    2009-03-31

    A gas-separation membrane module assembly and a gas-separation process using the assembly. The assembly includes a set of tubes, each containing gas-separation membranes, arranged within a housing. The housing contains a tube sheet that divides the space within the housing into two gas-tight spaces. A permeate collection system within the housing gathers permeate gas from the tubes for discharge from the housing.

  4. Hybrid membranes for fuel cells

    Science.gov (United States)

    Bochkareva, S. S.; Shashkina, S. S.

    2018-01-01

    Fuel cells are a very efficient, reliable, durable, and environmentally friendly energy source. Membranes for fuel cells were developed based on nitrogen-containing high-molecular compounds and organic–inorganic composites. Their electrical conductivities were measured. The influence of a silicon block of composites on the proton exchange properties of membranes was proved.The comparative characterization of the studied materials was performed.

  5. Membrane structure in disease and drug therapy

    National Research Council Canada - National Science Library

    Zimmer, G

    2000-01-01

    ...) interaction with membranous transport systems (opening or closing of ion or substrate channels); (2) reaction with receptors; (3) activation or inhibition of membrane enzymes; or (4) cytosolic membranous signaling and exchange. These consequences within the membrane influence intracellular wellbeing: life is possible only if a bala...

  6. Ninth International Workshop on Plant Membrane Biology

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    This report is a compilation of abstracts from papers which were discussed at a workshop on plant membrane biology. Topics include: plasma membrane ATP-ases; plant-environment interactions, membrane receptors; signal transduction; ion channel physiology; biophysics and molecular biology; vaculor H+ pumps; sugar carriers; membrane transport; and cellular structure and function.

  7. Nanomaterial-enabled membranes for water treatment

    Science.gov (United States)

    Rogensues, Adam Roy

    Incorporating engineered nanomaterials as components of synthetic membranes can improve their separation performance and endow membranes with additional functions. This work explores two approaches to the design of membranes modified with nanomaterials. In the first chapter, exfoliated graphite nanoplatelets (xGnP) decorated with gold nanoparticles were embedded in a polysulfone matrix to fabricate phase inversion nanocomposite membranes. The cast membranes were evaluated as flow-through membrane reactors in experiments on the catalytic reduction of 4-nitrophenol. The nanocomposite membranes were not as catalytically efficient as those fabricated by modifying anodized alumina membranes polyelectrolyte multilayers (PEMs) containing gold nanoparticles. However, because of the facility of membrane casting by phase inversion and new opportunities enabled by the demonstrated hierarchy-based approach to nanocomposite membrane design, such membrane may hold commercial promise. In the second part of the study, the practicability of PEM-based nanofiltration was evaluated under conditions of precipitative fouling (i.e. scaling) by calcium sulfate. Polyelectrolytes were deposited onto 50 kDa polyethersulfone membranes to create PEM-based nanofiltration membranes. The prepared membranes were compared with the commercial NF270 membrane in terms of flux and rejection performance, as well as the morphology of gypsum crystals formed on the membrane surface. None of the PEM coatings tested inhibited scale formation.

  8. Hydrogen purifier module with membrane support

    Science.gov (United States)

    A hydrogen purifier utilizing a hydrogen-permeable membrane to purify hydrogen from mixed gases containing hydrogen is disclosed. Improved mechanical support for the permeable membrane is described, enabling forward or reverse differential pressurization of the membrane, which further stabilizes the membrane from wrinkling upon hydrogen uptake.

    2012-07-24

    A hydrogen purifier utilizing a hydrogen-permeable membrane to purify hydrogen from mixed gases containing hydrogen is disclosed. Improved mechanical support for the permeable membrane is described, enabling forward or reverse differential pressurization of the membrane, which further stabilizes the membrane from wrinkling upon hydrogen uptake.

  9. Inflation and Failure of Polymeric Membranes

    DEFF Research Database (Denmark)

    Hassager, Ole; Neergaard, Jesper

    2000-01-01

    We consider the inflation of an axisymmetric polymeric membrane.Some membranes composed of viscoelastic materialsdescribed by a Mooney-Rivlin model show a monotone increasingpressure during inflation. These materialsdevelop a homogeneous membrane thickness in agreement with the Considere...... is found to stabilize the inflated polymer membrane....

  10. Membrane properties for permeability testing: Skin versus synthetic membranes.

    Science.gov (United States)

    Haq, Anika; Dorrani, Mania; Goodyear, Benjamin; Joshi, Vivek; Michniak-Kohn, Bozena

    2018-03-25

    Synthetic membranes that are utilized in diffusion studies for topical and transdermal formulations are usually porous thin polymeric sheets for example cellulose acetate (CA) and polysulfones. In this study, the permeability of human skin was compared using two synthetic membranes: cellulose acetate and Strat-M® membrane and lipophilic and hydrophilic compounds either as saturated or formulated solutions as well as marketed dosage forms. Our data suggests that hydrophilic compounds have higher permeation in Strat-M membranes compared with lipophilic ones. High variation in permeability values, a typical property of biological membranes, was not observed with Strat-M. In addition, the permeability of Strat-M was closer to that of human skin than that of cellulose acetate (CA > Strat-M > Human skin). Our results suggest that Strat-M with little or no lot to lot variability can be applied in pilot studies of diffusion tests instead of human skin and is a better substitute than a cellulose acetate. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Superhydrophobic Membrane Contactor for Acid Gas Removal

    Science.gov (United States)

    Faiqotul Himma, Nurul; Gede Wenten, I.

    2017-07-01

    Gas-liquid membrane contactor has gained a great attention as an alternative to conventional absorption columns in acid gas removal from natural gas or post-combustion. The membrane contactor offers high mass transfer area and excellent operational flexibility. However, hydrophobic microporous membranes commonly used are still susceptible to wetting by liquid absorbents, leading to the deterioration of absorption performance in long-term operation. Therefore, many studies were recently directed to improve the membrane wetting resistant by endowing superhydrophobicity. This article then presents a review on superhydrophobic membrane development and its application for acid gas removal using membrane contactor. An overview of gas-liquid membrane contactor is firstly presented, followed by the preparation of superhydrophobic membranes. The performances of superhydrophobic membranes in acid gas absorption are then discussed, and the recommendation for future research is finally outlined. This review may provide an insight into the further development of superhydrophobic membrane contactor.

  12. Modeling electrically active viscoelastic membranes.

    Directory of Open Access Journals (Sweden)

    Sitikantha Roy

    Full Text Available The membrane protein prestin is native to the cochlear outer hair cell that is crucial to the ear's amplification and frequency selectivity throughout the whole acoustic frequency range. The outer hair cell exhibits interrelated dimensional changes, force generation, and electric charge transfer. Cells transfected with prestin acquire unique active properties similar to those in the native cell that have also been useful in understanding the process. Here we propose a model describing the major electromechanical features of such active membranes. The model derived from thermodynamic principles is in the form of integral relationships between the history of voltage and membrane resultants as independent variables and the charge density and strains as dependent variables. The proposed model is applied to the analysis of an active force produced by the outer hair cell in response to a harmonic electric field. Our analysis reveals the mechanism of the outer hair cell active (isometric force having an almost constant amplitude and phase up to 80 kHz. We found that the frequency-invariance of the force is a result of interplay between the electrical filtering associated with prestin and power law viscoelasticity of the surrounding membrane. Paradoxically, the membrane viscoelasticity boosts the force balancing the electrical filtering effect. We also consider various modes of electromechanical coupling in membrane with prestin associated with mechanical perturbations in the cell. We consider pressure or strains applied step-wise or at a constant rate and compute the time course of the resulting electric charge. The results obtained here are important for the analysis of electromechanical properties of membranes, cells, and biological materials as well as for a better understanding of the mechanism of hearing and the role of the protein prestin in this mechanism.

  13. Reconstitutions of mitochondrial inner membrane remodeling.

    Science.gov (United States)

    Barbot, Mariam; Meinecke, Michael

    2016-10-01

    Biological membranes exhibit function-related shapes, leading to a plethora of complex and beautiful cell and cell organellar morphologies. Most if not all of these structures have evolved for a particular physiological reason. The shapes of these structures are formed by physical forces that operate on membranes. To create particular shaped cells and cell organelles, membranes must undergo deformations which are determined by the structure and elasticity of the membrane and this process is most probable driven by proteins, lipids and/or interplay of both Zimmerberg and Kozlov (2006). Therefore, an important question of current cell biology in conjunction with physics and mathematics is to elucidate the functional cause for these different membrane morphologies as well as how they are formed. One of the most peculiar membrane shapes is observed in mitochondria. These organelles are surrounded by two membranes and especially the convoluted inner membrane displays a complex ultra-structure. A molecular understanding of how this membrane is shaped is missing to a large extent. Unlike membrane remodeling in classical curvature-dependent processes like clathrin-mediated endocytosis, mitochondria are most likely shaped by integral membrane proteins. Following, we will review the current knowledge of inner mitochondrial membrane architecture and discuss recent findings and advances in understanding the factors that shape this membrane. We will address pending questions especially with regard to the experimentally challenging nature of investigating membrane bending by hydrophobic integral membrane proteins. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Gas transmission through microporous membranes

    Science.gov (United States)

    Turel, Tacibaht

    2008-10-01

    An ideal protective clothing material should be a good barrier against harmful gases or vapor while allowing moisture vapor and air passage through the material. In the study and design of barrier materials, one of the critical issues is to balance these requirements, which may sometimes be mutually exclusive. Therefore it is critical to understand the macroscopic and microscopic structure of the attack mechanisms as well as the barrier materials and the transport phenomena in such systems. In this study, air and gas transmission through barrier systems consisting of porous membranes was investigated experimentally and a molecular-level probabilistic model was constructed to evaluate the effect of various parameters on the gas flow. The effect of membrane parameters such as porosity, pore size distribution, thickness as well as gas parameters such as molecule diameters were examined at single layer as well as multiple layers. To understand the gas behavior for harmful chemicals and to ensure safety during experimental studies, mimics of such gases were obtained which were comparable to the actual gases in shape, molecular weight and other chemical properties. Air, ammonia and several mimic gases of harmful chemical agents were studied. Beta-pinene was used as a mimic of sarin and prenol was used as a mimic of nitrogen mustard. Gas transmission experiments were conducted on polyester, nylon and polypropylene membranes each of which had different porosity and pore size distributions. Experiments were done at different pressure values and a comparison was made between permeability testing machines based on volumetric and manometric principles as to their ability to accommodate high permeability membranes. Physical and chemical adsorption of such gases on porous membranes was also investigated after the addition of active elements on the membrane surfaces which can interact with the gas molecules. An experimental setup was developed to measure concentration changes

  15. Impact of sludge flocs on membrane fouling in membrane bioreactors

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Niessen, Wolfgang; Jørgensen, Mads Koustrup

    of divalent ions such as calcium and iron. Furthermore, it was shown that the ratio between cations and EPS was important for the fouling potential of the sludge. A high ratio between divalent ions and EPS reduced membrane fouling as soluble EPS were adsorbed and bound within the sludge flocs. Strong compact...... flocs reduced membrane fouling, and more compact and strong flocs were formed if the concentration of divalent ions were high. Sludge was fractionated by centrifugation providing supernatant with soluble EPS and colloidal particles but without flocs. Filtration test on untreated sludge and supernatant...

  16. Dietary fat composition influences tissue lipid profile and gene expression in Fischer-344 rats.

    Science.gov (United States)

    Zhou, Albert L; Hintze, Korry J; Jimenez-Flores, Rafael; Ward, Robert E

    2012-12-01

    The AIN-76A diet causes fatty liver in rodents when fed for long periods of time. The aim of this study was to utilize fatty acid analysis and transcriptomics to investigate the effects of different fat sources in the AIN-76A diet on tissue lipid profiles and gene expression in male, weanling Fischer-344 rats. Animals were fed isocaloric diets that differed only in the fat source: (1) corn oil (CO) (2) anhydrous milk fat (AMF), and (3) AMF supplemented with 10% phospholipids from the milk fat globule membrane (AMF-MFGM). There were no differences in food intake, body weight, growth rate, or body fat composition among the groups, and the fatty acid compositions of red blood cells (RBC), plasma, muscle, and visceral adipose tissues reflected the dietary fat sources. Modifying the fat source resulted in 293 genes differentially regulated in skeletal muscle, 1,124 in adipose, and 831 in liver as determined by analysis of variance (ANOVA). Although tissue fatty acid profiles mostly reflected the diet, there were several quantitative differences in lipid classes in the liver and plasma. The AMF diet resulted in the highest level of hepatic triacylglycerols, but the lowest level in plasma. The CO diet resulted in significant accumulation of hepatic unesterified fatty acids and decreased DGAT expression and activity, a potential trigger for steatohepatitis. These results indicate that the fatty acid composition and presence of polar lipids in the AIN-76A diets have significant effects on lipid partitioning, gene expression, and potentially the development of liver pathology.

  17. Zwitterionic materials for antifouling membrane surface construction.

    Science.gov (United States)

    He, Mingrui; Gao, Kang; Zhou, Linjie; Jiao, Zhiwei; Wu, Mengyuan; Cao, Jialin; You, Xinda; Cai, Ziyi; Su, Yanlei; Jiang, Zhongyi

    2016-08-01

    Membrane separation processes are often perplexed by severe and ubiquitous membrane fouling. Zwitterionic materials, keeping electric neutrality with equivalent positive and negative charged groups, are well known for their superior antifouling properties and have been broadly utilized to construct antifouling surfaces for medical devices, biosensors and marine coatings applications. In recent years, zwitterionic materials have been more and more frequently utilized for constructing antifouling membrane surfaces. In this review, the antifouling mechanisms of zwitterionic materials as well as their biomimetic prototypes in cell membranes will be discussed, followed by the survey of common approaches to incorporate zwitterionic materials onto membrane surfaces including surface grafting, surface segregation, biomimetic adhesion, surface coating and so on. The potential applications of these antifouling membranes are also embedded. Finally, we will present a brief perspective on the future development of zwitterionic materials modified antifouling membranes. Membrane fouling is a severe problem hampering the application of membrane separation technology. The properties of membrane surfaces play a critical role in membrane fouling and antifouling behavior/performance. Antifouling membrane surface construction has evolved as a hot research issue for the development of membrane processes. Zwitterionic modification of membrane surfaces has been recognized as an effective strategy to resist membrane fouling. This review summarizes the antifouling mechanisms of zwitterionic materials inspired by cell membranes as well as the popular approaches to incorporate them onto membrane surfaces. It can help form a comprehensive knowledge about the principles and methods of modifying membrane surfaces with zwitterionic materials. Finally, we propose the possible future research directions of zwitterionic materials modified antifouling membranes. Copyright © 2016 Acta Materialia Inc

  18. Nanoengineered membranes for controlled transport

    Science.gov (United States)

    Doktycz, Mitchel J [Oak Ridge, TN; Simpson, Michael L [Knoxville, TN; McKnight, Timothy E [Greenback, TN; Melechko, Anatoli V [Oak Ridge, TN; Lowndes, Douglas H [Knoxville, TN; Guillorn, Michael A [Knoxville, TN; Merkulov, Vladimir I [Oak Ridge, TN

    2010-01-05

    A nanoengineered membrane for controlling material transport (e.g., molecular transport) is disclosed. The membrane includes a substrate, a cover definining a material transport channel between the substrate and the cover, and a plurality of fibers positioned in the channel and connected to an extending away from a surface of the substrate. The fibers are aligned perpendicular to the surface of the substrate, and have a width of 100 nanometers or less. The diffusion limits for material transport are controlled by the separation of the fibers. In one embodiment, chemical derivitization of carbon fibers may be undertaken to further affect the diffusion limits or affect selective permeability or facilitated transport. For example, a coating can be applied to at least a portion of the fibers. In another embodiment, individually addressable carbon nanofibers can be integrated with the membrane to provide an electrical driving force for material transport.

  19. Experimental approaches to membrane thermodynamics

    DEFF Research Database (Denmark)

    Westh, Peter

    2009-01-01

    Thermodynamics describes a system on the macroscopic scale, yet it is becoming an important tool for the elucidation of many specific molecular aspects of membrane properties. In this note we discuss this application of thermodynamics, and give a number of examples on how thermodynamic measuremen...... have contributed to the understanding of specific membrane phenomena. We mainly focus on non-specific interactions of bilayers and small molecules (water and solutes) in the surrounding solvent, and the changes in membrane properties they bring about. Differences between thermodynamic...... and stoichiometric (structural) definitions of non-specific binding or partitioning are emphasized, and it is concluded that this distinction is important for weak, but not for strong, interactions....

  20. Mesoscopic models of biological membranes

    DEFF Research Database (Denmark)

    Venturoli, M.; Sperotto, Maria Maddalena; Kranenburg, M.

    2006-01-01

    Phospholipids are the main components of biological membranes and dissolved in water these molecules self-assemble into closed structures, of which bilayers are the most relevant from a biological point of view. Lipid bilayers are often used, both in experimental and by theoretical investigations......, as model systems to understand the fundamental properties of biomembranes. The properties of lipid bilayers can be studied at different time and length scales. For some properties it is sufficient to envision a membrane as an elastic sheet, while for others it is important to take into account the details...... to coarse grain a biological membrane. The conclusion of this comparison is that there can be many valid different strategies, but that the results obtained by the various mesoscopic models are surprisingly consistent. A second objective of this review is to illustrate how mesoscopic models can be used...

  1. Multilayered Magnetic Gelatin Membrane Scaffolds

    Science.gov (United States)

    Samal, Sangram K.; Goranov, Vitaly; Dash, Mamoni; Russo, Alessandro; Shelyakova, Tatiana; Graziosi, Patrizio; Lungaro, Lisa; Riminucci, Alberto; Uhlarz, Marc; Bañobre-López, Manuel; Rivas, Jose; Herrmannsdörfer, Thomas; Rajadas, Jayakumar; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L.; Dediu, V. Alek

    2016-01-01

    A versatile approach for the design and fabrication of multilayer magnetic scaffolds with tunable magnetic gradients is described. Multilayer magnetic gelatin membrane scaffolds with intrinsic magnetic gradients were designed to encapsulate magnetized bioagents under an externally applied magnetic field for use in magnetic-field-assisted tissue engineering. The temperature of the individual membranes increased up to 43.7 °C under an applied oscillating magnetic field for 70 s by magnetic hyperthermia, enabling the possibility of inducing a thermal gradient inside the final 3D multilayer magnetic scaffolds. On the basis of finite element method simulations, magnetic gelatin membranes with different concentrations of magnetic nanoparticles were assembled into 3D multilayered scaffolds. A magnetic-gradient-controlled distribution of magnetically labeled stem cells was demonstrated in vitro. This magnetic biomaterial–magnetic cell strategy can be expanded to a number of different magnetic biomaterials for various tissue engineering applications. PMID:26451743

  2. Membrane interaction of retroviral Gag proteins

    Directory of Open Access Journals (Sweden)

    Robert Alfred Dick

    2014-04-01

    Full Text Available Assembly of an infectious retroviral particle relies on multimerization of the Gag polyprotein at the inner leaflet of the plasma membrane. The three domains of Gag common to all retroviruses-- MA, CA, and NC-- provide the signals for membrane binding, assembly, and viral RNA packaging, respectively. These signals do not function independently of one another. For example, Gag multimerization enhances membrane binding and is more efficient when NC is interacting with RNA. MA binding to the plasma membrane is governed by several principles, including electrostatics, recognition of specific lipid head groups, hydrophobic interactions, and membrane order. HIV-1 uses many of these principles while Rous sarcoma virus (RSV appears to use fewer. This review describes the principles that govern Gag interactions with membranes, focusing on RSV and HIV-1 Gag. The review also defines lipid and membrane behavior, and discusses the complexities in determining how lipid and membrane behavior impact Gag membrane binding.

  3. Synthetic Biomimetic Membranes and Their Sensor Applications

    Directory of Open Access Journals (Sweden)

    Young-Rok Kim

    2012-07-01

    Full Text Available Synthetic biomimetic membranes provide biological environments to membrane proteins. By exploiting the central roles of biological membranes, it is possible to devise biosensors, drug delivery systems, and nanocontainers using a biomimetic membrane system integrated with functional proteins. Biomimetic membranes can be created with synthetic lipids or block copolymers. These amphiphilic lipids and polymers self-assemble in an aqueous solution either into planar membranes or into vesicles. Using various techniques developed to date, both planar membranes and vesicles can provide versatile and robust platforms for a number of applications. In particular, biomimetic membranes with modified lipids or functional proteins are promising platforms for biosensors. We review recent technologies used to create synthetic biomimetic membranes and their engineered sensors applications.

  4. Uranium preconcentration from seawater using adsorptive membranes

    International Nuclear Information System (INIS)

    Das, Sadananda; Pandey, A.K.; Manchanda, V.K.; Athawale, A.A.

    2009-01-01

    Uranium recovery from bio-aggressive but lean feed like seawater is a challenging problem as it requires in situ preconcentration of uranium in presence of huge excess of competing ions with fast sorption kinetics. In our laboratory, widely used amidoxime membrane (AO-membrane) was evaluated for uranium sorption under seawater conditions. This study indicated that AO-membrane was inherently slow because of the complexation chemistry involved in transfer of U(VI) from (UO 2 (CO 3 ) 3 ) 4 - to AO sites in membrane. In order to search better options, several chemical compositions of membrane were scanned for their efficacy for uranium preconcentration from seawater, and concluded that EGMP-membrane offers several advantages over AO-membrane. In this paper, the comparison of EGMP-membrane with AO-membrane for uranium sorption under seawater conditions has been reviewed. (author)

  5. Membrane bending by protein-protein crowding.

    Science.gov (United States)

    Stachowiak, Jeanne C; Schmid, Eva M; Ryan, Christopher J; Ann, Hyoung Sook; Sasaki, Darryl Y; Sherman, Michael B; Geissler, Phillip L; Fletcher, Daniel A; Hayden, Carl C

    2012-09-01

    Curved membranes are an essential feature of dynamic cellular structures, including endocytic pits, filopodia protrusions and most organelles. It has been proposed that specialized proteins induce curvature by binding to membranes through two primary mechanisms: membrane scaffolding by curved proteins or complexes; and insertion of wedge-like amphipathic helices into the membrane. Recent computational studies have raised questions about the efficiency of the helix-insertion mechanism, predicting that proteins must cover nearly 100% of the membrane surface to generate high curvature, an improbable physiological situation. Thus, at present, we lack a sufficient physical explanation of how protein attachment bends membranes efficiently. On the basis of studies of epsin1 and AP180, proteins involved in clathrin-mediated endocytosis, we propose a third general mechanism for bending fluid cellular membranes: protein-protein crowding. By correlating membrane tubulation with measurements of protein densities on membrane surfaces, we demonstrate that lateral pressure generated by collisions between bound proteins drives bending. Whether proteins attach by inserting a helix or by binding lipid heads with an engineered tag, protein coverage above ~20% is sufficient to bend membranes. Consistent with this crowding mechanism, we find that even proteins unrelated to membrane curvature, such as green fluorescent protein (GFP), can bend membranes when sufficiently concentrated. These findings demonstrate a highly efficient mechanism by which the crowded protein environment on the surface of cellular membranes can contribute to membrane shape change.

  6. Mesoscopic models of biological membranes

    DEFF Research Database (Denmark)

    Venturoli, M.; Sperotto, Maria Maddalena; Kranenburg, M.

    2006-01-01

    Phospholipids are the main components of biological membranes and dissolved in water these molecules self-assemble into closed structures, of which bilayers are the most relevant from a biological point of view. Lipid bilayers are often used, both in experimental and by theoretical investigations...... to coarse grain a biological membrane. The conclusion of this comparison is that there can be many valid different strategies, but that the results obtained by the various mesoscopic models are surprisingly consistent. A second objective of this review is to illustrate how mesoscopic models can be used...

  7. Robust mixed conducting membrane structure

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a membrane structure, comprising in said order a first electronically conducting layer, an ionically conducting layer, and a second electronically conducting layer, characterized in that the first and second electronically conducting layers are internally short...... circuited. The present invention further provides a method of producing the above membrane structure, comprising the steps of : providing a ionically conducting layer; applying at least one layer of electronically conducting material on each side of said ionically conducting layer; sintering the multilayer...... structure; and impregnating the electronically conducting layers with a catalyst material or catalyst precursor material....

  8. Membrane processes in nuclear technologies

    International Nuclear Information System (INIS)

    Zakrzewska-Trznadel, G.

    2006-01-01

    The treatment of radioactive wastes is necessary taking into account the potential hazard of radioactive substances to human health and surrounding environment. The choice of appropriate technology depends on capital and operational costs, wastes amount and their characteristics, appointed targets of the process, e.g. the values of decontamination factors and volume reduction coefficients. The conventional technologies applied for radioactive waste processing, such as precipitation coupled with sedimentation, ion exchange and evaporation have many drawbacks. These include high energy consumption and formation of secondary wastes, e.g. the sludge from sediment tanks, spent ion exchange adsorbents and regeneration solutions. There are also many limitations of such processes, i.e. foaming and drop entrainment in evaporators, loses of solvents and production of secondary wastes in solvent extraction or bed clogging in ion exchange columns. Membrane processes as the newest achievement of the process engineering can successfully supersede many non-effective, out-of-date methods. But in some instances they can also complement these methods whilst improving the parameters of effluents and purification economy. This monograph presents own research data on the application of recent achievements in the area of membrane processes for solving selected problems in nuclear technology. Relatively big space was devoted to the use of membrane processing of low and intermediate radioactive liquid wastes because of numerous applications of these processes in nuclear centres over the world and also because of the interests of the author that was reflected by her recent research projects and activity. This work presents a review on the membrane methods recently introduced into the nuclear technology against the background of the other, commonly applied separation techniques, with indications of the possibilities and prospects for their further developments. Particular attention was paid

  9. Large scale biomimetic membrane arrays

    DEFF Research Database (Denmark)

    Hansen, Jesper Søndergaard; Perry, Mark; Vogel, Jörg

    2009-01-01

    To establish planar biomimetic membranes across large scale partition aperture arrays, we created a disposable single-use horizontal chamber design that supports combined optical-electrical measurements. Functional lipid bilayers could easily and efficiently be established across CO2 laser micro...... peptides and proteins. Next, we tested the scalability of the biomimetic membrane design by establishing lipid bilayers in rectangular 24 x 24 and hexagonal 24 x 27 aperture arrays, respectively. The results presented show that the design is suitable for further developments of sensitive biosensor assays...

  10. Polymeric and Lipid Membranes-From Spheres to Flat Membranes and vice versa.

    Science.gov (United States)

    Saveleva, Mariia S; Lengert, Ekaterina V; Gorin, Dmitry A; Parakhonskiy, Bogdan V; Skirtach, Andre G

    2017-08-15

    Membranes are important components in a number of systems, where separation and control of the flow of molecules is desirable. Controllable membranes represent an even more coveted and desirable entity and their development is considered to be the next step of development. Typically, membranes are considered on flat surfaces, but spherical capsules possess a perfect "infinite" or fully suspended membranes. Similarities and transitions between spherical and flat membranes are discussed, while applications of membranes are also emphasized.

  11. Membrane potentials of membranes with fixed ionic sites

    NARCIS (Netherlands)

    van den Berg, Albert; van der Wal, P.D.; van der Wal, P.D.; Skowronska-ptasinska, M.; Sudhölter, E.J.R.; Sudholter, Ernst; Bergveld, Piet; Reinhoudt, David

    1990-01-01

    A theoretical model has been developed to simulate the formation of a membrane potential as a function of physically accessible parameters. The description is an extension of the well-known Teorell-Meyer-Sievers (TMS) model, now including free and fixed ionic sites and free and fixed neutral

  12. Efficient preparation and analysis of membrane and membrane protein systems

    Czech Academy of Sciences Publication Activity Database

    Javanainen, M.; Martinez-Seara, Hector

    2016-01-01

    Roč. 1858, č. 10 (2016), s. 2468-2482 ISSN 0005-2736 Institutional support: RVO:61388963 Keywords : tools and software * membrane building * protein insertion * molecular dynamics * lipid bilayer Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2016

  13. STUDI MEMBRAN KITOSAN DARI KULIT LOBSTER BAMBU SEBAGAI MEMBRAN FILTRASI

    Directory of Open Access Journals (Sweden)

    Ni Nyoman Putri Windari

    2016-02-01

    Full Text Available The study of the extraction and characterization of chitosan from skin waste of Bamboo Lobster (Panulirus versicolor has been done. Chitosan is extracted using conventional method, namely the initial process: cleaning and drying (pretreatment, demineralization, deproteination, and deacetylation. The chitosan obtained has been used to prepare chitosan membrane 2% with acetic acid 1% as solvent. The membrane prepared by phase inversion method withprecipitation through solvent evaporation. The prepared membranes were characterized by FTIR spectrophotometer, Nova 1200e by BJH method and filtration method. The results obtained that degree of deacetylation (DD of chitosan is 70.016%. The thickness of the membrane is 0.361 mm. The FTIR spectra show that functional groups obtained are -NH, -CH, C=O, C-O and -CN. From BJH method obtained that the pore radius is 1.69 nm and pore density is 8.95 x 105pores/m3. From the filtration method obtained that at each pressure, 80-85 kPa and 90-100 kPa, the PWF values are 381.232 and 454.545 L/m2.h, respectively.

  14. Membrane distillation : a new approach using composite membranes

    NARCIS (Netherlands)

    Franken, Antonius Christianus Maria

    1988-01-01

    In this thesis several aspects of the membrane distillation process and the thermally driven pervaporation process have been described. Both processes differ essentially from each other as far as their mechanism of separation and their applicability is concerned. From a practical point of view,

  15. Diffusion of Integral Membrane Proteins in Protein-Rich Membranes

    Czech Academy of Sciences Publication Activity Database

    Javanainen, M.; Martinez-Seara, Hector; Metzler, R.; Vattulainen, I.

    2017-01-01

    Roč. 8, č. 17 (2017), s. 4308-4313 ISSN 1948-7185 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388963 Keywords : giant unilamellar vesicles * single-molecule tracking * lipid bilayer membranes Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 9.353, year: 2016

  16. Solvent-resistant microporous polymide membranes

    Science.gov (United States)

    Miller, Warren K.; McCray, Scott B.; Friesen, Dwayne T.

    1998-01-01

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  17. 3D Membrane Imaging and Porosity Visualization

    KAUST Repository

    Sundaramoorthi, Ganesh

    2016-03-03

    Ultrafiltration asymmetric porous membranes were imaged by two microscopy methods, which allow 3D reconstruction: Focused Ion Beam and Serial Block Face Scanning Electron Microscopy. A new algorithm was proposed to evaluate porosity and average pore size in different layers orthogonal and parallel to the membrane surface. The 3D-reconstruction enabled additionally the visualization of pore interconnectivity in different parts of the membrane. The method was demonstrated for a block copolymer porous membrane and can be extended to other membranes with application in ultrafiltration, supports for forward osmosis, etc, offering a complete view of the transport paths in the membrane.

  18. A Model for Membrane Fusion

    Science.gov (United States)

    Ngatchou, Annita

    2010-01-01

    Pheochromocytoma is a tumor of the adrenal gland which originates from chromaffin cells and is characterized by the secretion of excessive amounts of neurotransmitter which lead to high blood pressure and palpitations. Pheochromocytoma contain membrane bound granules that store neurotransmitter. The release of these stored molecules into the extracellular space occurs by fusion of the granule membrane with the cell plasma membrane, a process called exocytosis. The molecular mechanism of this membrane fusion is not well understood. It is proposed that the so called SNARE proteins [1] are the pillar of vesicle fusion as their cleavage by clostridial toxin notably, Botulinum neurotoxin and Tetanus toxin abrogate the secretion of neurotransmitter [2]. Here, I describe how physical principles are applied to a biological cell to explore the role of the vesicle SNARE protein synaptobrevin-2 in easing granule fusion. The data presented here suggest a paradigm according to which the movement of the C-terminal of synaptobrevin-2 disrupts the lipid bilayer to form a fusion pore through which molecules can exit.

  19. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Membrane Trafficking and Vesicle Fusion: Post-Palade Era Researchers Win the Nobel Prize. Riddhi Atul Jani Subba Rao Gangi Setty. General Article Volume 19 Issue 5 May 2014 pp 421-445 ...

  20. Stability of supported liquid membranes

    NARCIS (Netherlands)

    Neplenbroek, Antonius Maria

    1989-01-01

    This thesis deals with the stability of supported liquid membranes (SLMs). The use of SLMs, in which an extraction liquid containing a carrier is immobilized in the pores of a microporous support, has recently been introduced as a promising new separation technique. Some advantages ascribed to this

  1. Membrane adsorbers : development and applications

    NARCIS (Netherlands)

    Avramescu, M.E.

    2002-01-01

    Bioaffinity separation principally asks for membranes that show a good compatibility to the targeted biological fluids, provide coupling sites for (bio)ligands and posses a hydrophilic surface to reduce non-specific adsorption caused by hydrophobic atraction. Due to its good blood compatibility and

  2. Preparation of gas selective membranes

    Science.gov (United States)

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

    1988-01-01

    Gas separation membranes which possess improved characteristics as exemplified by selectivity and flux may be prepared by coating a porous organic polymer support with a solution or emulsion of a plasticizer and an organic polymer, said coating being effected at subatmospheric pressures in order to increase the penetration depth of the coating material.

  3. The Plasma Membrane Calcium Pump

    Science.gov (United States)

    Rasmussen, H.

    1983-01-01

    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  4. Guanidinium Pairing Facilitates Membrane Translocation

    Czech Academy of Sciences Publication Activity Database

    Allolio, Christoph; Baxová, Katarína; Vazdar, M.; Jungwirth, Pavel

    2016-01-01

    Roč. 120, č. 1 (2016), s. 143-153 ISSN 1520-6106 R&D Projects: GA ČR GA13-06181S Institutional support: RVO:61388963 Keywords : ab initio molecular dynamics * guanidinium * like charge pairing * membrane Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.177, year: 2016

  5. Comparative antioxidant capacity, membrane stabilization ...

    African Journals Online (AJOL)

    Comparative antioxidant capacity, membrane stabilization, polyphenol composition and cytotoxicity of the leaf and stem of Cissus multistriata. ... standard anti-inflammatory drug (Indomethacin) used. The extracts are less toxic to the cell (Arthenia salina) with their LC/EC50 higher than that of standard potassium dichromate ...

  6. Challenges in Commercializing Biomimetic Membranes.

    Science.gov (United States)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine; Braekevelt, Sylvie; Lauritzen, Karsten; Hélix-Nielsen, Claus

    2015-11-05

    The discovery of selective water channel proteins-aquaporins-has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market-in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  7. PREMATURE RUPTURE OF THE MEMBRANES*

    African Journals Online (AJOL)

    In patients presenting with premature rupture of the membranes there are two factors which influence the foetal morbidity and mortality. These factors are prema- turity and intra-uterine infection. The purpose of this analysis was to elucidate which factor carried the greater risk to the foetus. Recently there has been a spate of.

  8. Extracorporeal membrane oxygenation (ECMO) | Richards ...

    African Journals Online (AJOL)

    Extracorporeal membrane oxygenation (ECMO) is increasingly being employed in South African intensive care units for the management of patients with refractory hypoxaemia and for haemodynamic support, particularly following cardiothoracic procedures. ECMO is expensive, however, and there is a danger that this ...

  9. Basement membrane proteoglycans and development

    DEFF Research Database (Denmark)

    Couchman, J R; Abrahamson, D R; McCarthy, K J

    1993-01-01

    -CSPG was only strongly expressed in the vasculature invading late comma stage glomeruli, and later in presumptive and mature Bowman's capsule. Over the first six to eight weeks, the capillary basement membranes contained BM-CSPG, but in gradually decreasing amounts until it became completely undetectable...

  10. Osmosis and the Marvelous Membrane.

    Science.gov (United States)

    Cocanour, Barbara; Bruce, Alease S.

    1985-01-01

    Shows how the natural membrane of a decalcified chicken egg can demonstrate the principle of osmosis within a single class period. Various glucose and saline solutions used, periods of time, physiological effects experiments, and correction for differences in initial weights are noted. (DH)

  11. Intelligent Membranes: Dream or Reality?

    Science.gov (United States)

    Gugliuzza, Annarosa

    2013-07-15

    Intelligent materials are claimed to overcome current drawbacks associated with the attainment of high standards of life, health, security and defense. Membrane-based sensors represent a category of smart systems capable of providing a large number of benefits to different markets of textiles, biomedicine, environment, chemistry, agriculture, architecture, transport and energy. Intelligent membranes can be characterized by superior sensitivity, broader dynamic range and highly sophisticated mechanisms of autorecovery. These prerogatives are regarded as the result of multi-compartment arrays, where complementary functions can be accommodated and well-integrated. Based on the mechanism of "sense to act", stimuli-responsive membranes adapt themselves to surrounding environments, producing desired effects such as smart regulation of transport, wetting, transcription, hydrodynamics, separation, and chemical or energy conversion. Hopefully, the design of new smart devices easier to manufacture and assemble can be realized through the integration of sensing membranes with wireless networks, looking at the ambitious challenge to establish long-distance communications. Thus, the transfer of signals to collecting systems could allow continuous and real-time monitoring of data, events and/or processes.

  12. Challenges in Commercializing Biomimetic Membranes

    Directory of Open Access Journals (Sweden)

    Mark Perry

    2015-11-01

    Full Text Available The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market—in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  13. Comparative antioxidant capacity, membrane stabilization ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... In this present study, a comparative evaluation of the antioxidant capacities, phenol and polyphenol composition, membrane stabilization, and cytotoxicity to brine shrimps (Arthemia salina) of the leaf and stem extracts of Cissus multistriata were carried out. 2,2- Diphenyl-1-picryl hydrazyl (DPPH) radical.

  14. Membrane Trafficking and Vesicle Fusion

    Indian Academy of Sciences (India)

    IAS Admin

    investigators were awarded the Nobel Prize in Physiology or. Medicine in 2013. Introduction. Membrane Transport: In the eukaryotic cell, a majority of proteins are made in the cytosol. But the transmembrane and secretory proteins are synthesized in an organelle called the rough endoplasmic reticulum (ER). These proteins ...

  15. Membrane microdomains in immunoreceptor signaling

    Czech Academy of Sciences Publication Activity Database

    Hořejší, Václav; Hrdinka, Matouš

    2014-01-01

    Roč. 588, č. 15 (2014), s. 2392-2397 ISSN 0014-5793 R&D Projects: GA ČR(CZ) GBP302/12/G101 Institutional support: RVO:68378050 Keywords : membrane raft * microdomain * immunoreceptor Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.169, year: 2014

  16. Intelligent Membranes: Dream or Reality?

    Directory of Open Access Journals (Sweden)

    Annarosa Gugliuzza

    2013-07-01

    Full Text Available Intelligent materials are claimed to overcome current drawbacks associated with the attainment of high standards of life, health, security and defense. Membrane-based sensors represent a category of smart systems capable of providing a large number of benefits to different markets of textiles, biomedicine, environment, chemistry, agriculture, architecture, transport and energy. Intelligent membranes can be characterized by superior sensitivity, broader dynamic range and highly sophisticated mechanisms of autorecovery. These prerogatives are regarded as the result of multi-compartment arrays, where complementary functions can be accommodated and well-integrated. Based on the mechanism of “sense to act”, stimuli-responsive membranes adapt themselves to surrounding environments, producing desired effects such as smart regulation of transport, wetting, transcription, hydrodynamics, separation, and chemical or energy conversion. Hopefully, the design of new smart devices easier to manufacture and assemble can be realized through the integration of sensing membranes with wireless networks, looking at the ambitious challenge to establish long-distance communications. Thus, the transfer of signals to collecting systems could allow continuous and real-time monitoring of data, events and/or processes.

  17. Dense ceramic catalytic membranes and membrane reactors for energy and environmental applications.

    Science.gov (United States)

    Dong, Xueliang; Jin, Wanqin; Xu, Nanping; Li, Kang

    2011-10-21

    Catalytic membrane reactors which carry out separation and reaction in a single unit are expected to be a promising approach to achieve green and sustainable chemistry with less energy consumption and lower pollution. This article presents a review of the recent progress of dense ceramic catalytic membranes and membrane reactors, and their potential applications in energy and environmental areas. A basic knowledge of catalytic membranes and membrane reactors is first introduced briefly, followed by a short discussion on the membrane materials including their structures, composition and strategies for material development. The configuration of catalytic membranes, the design of membrane reaction processes and the high temperature sealing are also discussed. The performance of catalytic membrane reactors for energy and environmental applications are summarized and typical catalytic membrane reaction processes are presented and discussed. Finally, current challenges and difficulties related to the industrialization of dense ceramic membrane reactors are addressed and possible future research is also outlined.

  18. Cell-free system for synthesizing membrane proteins cell free method for synthesizing membrane proteins

    Science.gov (United States)

    Laible, Philip D; Hanson, Deborah K

    2013-06-04

    The invention provides an in vitro method for producing proteins, membrane proteins, membrane-associated proteins, and soluble proteins that interact with membrane-associated proteins for assembly into an oligomeric complex or that require association with a membrane for proper folding. The method comprises, supplying intracytoplasmic membranes from organisms; modifying protein composition of intracytoplasmic membranes from organism by modifying DNA to delete genes encoding functions of the organism not associated with the formation of the intracytoplasmic membranes; generating appropriate DNA or RNA templates that encode the target protein; and mixing the intracytoplasmic membranes with the template and a transcription/translation-competent cellular extract to cause simultaneous production of the membrane proteins and encapsulation of the membrane proteins within the intracytoplasmic membranes.

  19. Ceramic membranes for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Vincente-Mingarro, I.M. de; Pitarch, J.A. [Tecnologia y Gestion de la Innovacion, Madrid (Spain)

    1998-11-01

    The project is being carried out jointly by TGI, S.A., CIEMAT and CSIC-ICM to develop and evaluate new inorganic membranes of a ceramic type, with nanometric pore size for separation of contaminants and fuel enrichment, in gas mixtures from coal gasification. In order to achieve both the highest active and selective surface, a candle (150 mm length and 60 mm in diameter), with 30-40 % porosity and pore sizes of {lt}1 {mu}m was developed. The processing steps include the slip-casting of the first layer (porous support) in a way than after thermal treatment (1400-1600{degree}C) the desirable shape dimensions, strength, porosity and pore size were obtained. Then the support was dipped successively (colloidal filtration over the casting porous piece) in an appropriate suspension of alumina with lower grain size. The top layer was obtained by the sol-gel process so that through successive setting and heat treatment the pores were reduced to the nanometre size. CVD and CVI techniques were set up to develop membranes for gas separation with a high selectivity level. Experimental chemical infiltration `Membranes Development` on porous substrates has been achieved on disk and candle-shaped materials. Characterisation was by spectrophotometry (IRS). Kinetic studies of coating in order to find out reproducible conditions at low temperature were also carried out. Uniform recovery over the whole membrane surface is wanted. The CIEMAT`s Hot Gas Separation Plant (HGSP) works with gas mixtures at a maximum design temperature 773 K and pressures up to 50 bar. It comprises: a gas supply unit equipped with flow, temperature and pressure measuring and control systems; a heating system within the membrane which must be leak proof for high pressures; and an in-line gas chromatography system thus allowing the chemical composition of the gas entering, permeated and retained to be measured. 7 figs.

  20. Corrugated Membrane Fuel Cell Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grot, Stephen [President, Ion Power Inc.

    2013-09-30

    One of the most challenging aspects of traditional PEM fuel cell stacks is the difficulty achieving the platinum catalyst utilization target of 0.2 gPt/kWe set forth by the DOE. Good catalyst utilization can be achieved with state-of-the-art catalyst coated membranes (CCM) when low catalyst loadings (<0.3 mg/cm2) are used at a low current. However, when low platinum loadings are used, the peak power density is lower than conventional loadings, requiring a larger total active area and a larger bipolar plate. This results in a lower overall stack power density not meeting the DOE target. By corrugating the fuel cell membrane electrode structure, Ion Power?s goal is to realize both the Pt utilization targets as well as the power density targets of the DOE. This will be achieved by demonstrating a fuel cell single cell (50 cm2) with a twofold increase in the membrane active area over the geometric area of the cell by corrugating the MEA structure. The corrugating structure must be able to demonstrate the target properties of < 10 mOhm-cm2 electrical resistance at > 20 psi compressive strength over the active area, in combination with offering at least 80% of power density that can be achieved by using the same MEA in a flat plate structure. Corrugated membrane fuel cell structures also have the potential to meet DOE power density targets by essentially packaging more membrane area into the same fuel cell volume as compared to conventional stack constructions.

  1. Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

    KAUST Repository

    Wang, Xianbin

    2015-01-22

    Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.

  2. Membrane fouling mechanism of biofilm-membrane bioreactor (BF-MBR): Pore blocking model and membrane cleaning.

    Science.gov (United States)

    Zheng, Yi; Zhang, Wenxiang; Tang, Bing; Ding, Jie; Zheng, Yi; Zhang, Zhien

    2018-02-01

    Biofilm membrane bioreactor (BF-MBR) is considered as an important wastewater treatment technology that incorporates advantages of both biofilm and MBR process, as well as can alleviate membrane fouling, with respect to the conventional activated sludge MBR. But, to be efficient, it necessitates the establishment of proper methods for the assessment of membrane fouling. Four Hermia membrane blocking models were adopted to quantify and evaluate the membrane fouling of BF-MBR. The experiments were conducted with various operational conditions, including membrane types, agitation speeds and transmembrane pressure (TMP). Good agreement between cake formation model and experimental data was found, confirming the validity of the Hermia models for assessing the membrane fouling of BF-MBR and that cake layer deposits on membrane. Moreover, the influences of membrane types, agitation speeds and transmembrane pressure on the Hermia pore blocking coefficient of cake layer were investigated. In addition, the permeability recovery after membrane cleaning at various operational conditions was studied. This work confirms that, unlike conventional activated sludge MBR, BF-MBR possesses a low degree of membrane fouling and a higher membrane permeability recovery after cleaning. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Self-assembled Block Copolymer Membrane

    KAUST Repository

    Peinemann, Klaus-Viktor

    2012-12-20

    Embodiments of the invention include methods for the production of porous membranes. In certain aspects the methods are directed to producing polymeric porous membranes having a narrow pore size distribution.

  4. Fuel-Cell Structure Prevents Membrane Drying

    Science.gov (United States)

    Mcelroy, J.

    1986-01-01

    Embossed plates direct flows of reactants and coolant. Membrane-type fuel-cell battery has improved reactant flow and heat removal. Compact, lightweight battery produces high current and power without drying of membranes.

  5. Characterisation of adaptive fluidic silicone membrane lenses

    CSIR Research Space (South Africa)

    Schneider, F

    2009-09-01

    Full Text Available In this paper the auhtors compare the performance and optical quality of two types of adaptive fluidic silicone-membrane lenses. The membranes feature either a homogeneous thickness, or they are shaped resulting in an inhomogeneous cross...

  6. Tetrakis-amido high flux membranes

    Science.gov (United States)

    McCray, S.B.

    1989-10-24

    Composite RO membranes of a microporous polymeric support and a polyamide reaction product of a tetrakis-aminomethyl compound and a polyacylhalide are disclosed, said membranes exhibiting high flux and good chlorine resistance.

  7. PERVAPORATION USING ADSORBENT-FILLED MEMBRANES

    Science.gov (United States)

    Membranes containing selective fillers, such as zeolites and activated carbon, can improve the separation by pervaporation. Applications of adsorbent-filled membranes in pervaporation have been demonstrated by a number of studies. These applications include removal of organic co...

  8. Anion permselective membrane. [For redox fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, S.S.; Hodgdon, R.B.

    1978-01-01

    Experimental anion permeselective membranes were improved and characterized for use as separators in a chemical redox, power storage cell being developed at the NASA Lewis Research Center. The goal of minimal Fe/sup +3/ ion transfer was achieved for each candidate membrane system. Minimal membrane resistivity was demonstrated by reduction of film thickness using synthetic backing materials but usefulness of thin membranes was limited by the scarcity of compatible fabrics. The most durable and useful backing fabrics were modacrylics. One membrane, a copolymer of 4 vinylpyridine and vinyl benzylchloride was outstanding in overall electrochemical and physical properties. Long term (1000 hrs) membrane chemical and thermal durability in redox environment was shown by three candidate polymers and two membranes. The remainder had good durability at ambient temperature. Manufacturing capability was demonstrated for large scale production of membrane sheets 5.5 ft/sup 2/ in area for two candidate systems.

  9. Photothermal Membrane Distillation for Seawater Desalination.

    Science.gov (United States)

    Politano, Antonio; Argurio, Pietro; Di Profio, Gianluca; Sanna, Vanna; Cupolillo, Anna; Chakraborty, Sudip; Arafat, Hassan A; Curcio, Efrem

    2017-01-01

    Thermoplasmonic effects notably improve the efficiency of vacuum membrane distillation, an economically sustainable tool for high-quality seawater desalination. Poly(vinylidene fluoride) (PVDF) membranes filled with spherical silver nanoparticles are used, whose size is tuned for the aim. With the addition of plasmonic nanoparticles in the membrane, the transmembrane flux increases by 11 times, and, moreover, the temperature at the membrane interface is higher than bulk temperature. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. GOHAL!: sustainable membranes for alcohol dehydration

    DEFF Research Database (Denmark)

    Boffa, Vittorio

    2017-01-01

    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. This study provides a new basis for the rational design of the future generation of GO-based membranes......Treat, H2020-MSCA-RISE-2014 (n. 64555). [1] V. Boffa et. al., Carbon-based building blocks for alcohol dehydration membranes with disorder-enhanced water permeability, Carbon, under review....

  11. High energy irradiation of bacterial membrane vesicles

    International Nuclear Information System (INIS)

    De La Rosa, M.A.M.

    1977-01-01

    The interactions of membrane components and two well-defined transport systems in the E. coli ML 308-225 membrane vesicles with 60 Co gamma radiation were investigated. The results presented show that gamma radiation can monitor membrane components and functions of varying radiosensitivities. The possible application of high-energy radiation as a physical probe of membrane structure and functions is indeed promising

  12. Single channel analysis of membrane proteins in artificial bilayer membranes.

    Science.gov (United States)

    Bartsch, Philipp; Harsman, Anke; Wagner, Richard

    2013-01-01

    The planar lipid bilayer technique is a powerful experimental approach for electrical single channel recordings of pore-forming membrane proteins in a chemically well-defined and easily modifiable environment. Here we provide a general survey of the basic materials and procedures required to set up a robust bilayer system and perform electrophysiological single channel recordings of reconstituted proteins suitable for the in-depth characterization of their functional properties.

  13. Testing the membrane paradigm with holography

    NARCIS (Netherlands)

    de Boer, J.; Heller, M.P.; Pinzani-Fokeeva, N.

    2015-01-01

    One version of the membrane paradigm states that, as far as outside observers are concerned, black holes can be replaced by a dissipative membrane with simple physical properties located at the stretched horizon. We demonstrate that such a membrane paradigm is incomplete in several aspects. We argue

  14. Membrane Technologies for CO2 Capture

    NARCIS (Netherlands)

    Simons-Fischbein, K.

    2010-01-01

    This thesis investigates the potential of membrane technology for the effective CO2/CH4 separation. The work focuses on two different membrane processes to accomplish the separation: 1) The use of a gas-liquid membrane contactor for the selective absorption of CO2 from CH4 2) The use of thin, dense

  15. Pollen viability and membrane lipid composition

    NARCIS (Netherlands)

    Bilsen, van D.G.J.L.

    1993-01-01

    In this thesis membrane lipid composition is studied in relation to pollen viability during storage. Chapter 1 reviews pollen viability, membranes in the dry state and membrane changes associated with cellular aging. This chapter is followed by a study of age-related changes in phospholipid

  16. Submerged membrane distillation for desalination of water

    KAUST Repository

    Francis, Lijo

    2016-10-27

    Submerged membrane modules for use for desalination of water are disclosed. In one or more aspects, the membrane modules can be submerged either in a feed solution tank or the feed solution can pass through the lumen side of the membrane submerged within the tank. The feed solution can be a water-based feed stream containing an amount of salt.

  17. Silica incorporated membrane for wastewater based filtration

    Science.gov (United States)

    Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

    2017-10-01

    Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

  18. Membrane bioreactors for waste gas treatment.

    NARCIS (Netherlands)

    Reij, M.W.; Keurentjes, J.T.F.; Hartmans, S.

    1998-01-01

    This review describes the recent development of membrane reactors for biological treatment of waste gases. In this type of bioreactor gaseous pollutants are transferred through a membrane to the liquid phase, where micro-organisms degrade the pollutants. The membrane bioreactor combines the

  19. A review of water treatment membrane nanotechnologies

    KAUST Repository

    Pendergast, MaryTheresa M.

    2011-01-01

    Nanotechnology is being used to enhance conventional ceramic and polymeric water treatment membrane materials through various avenues. Among the numerous concepts proposed, the most promising to date include zeolitic and catalytic nanoparticle coated ceramic membranes, hybrid inorganic-organic nanocomposite membranes, and bio-inspired membranes such as hybrid protein-polymer biomimetic membranes, aligned nanotube membranes, and isoporous block copolymer membranes. A semi-quantitative ranking system was proposed considering projected performance enhancement (over state-of-the-art analogs) and state of commercial readiness. Performance enhancement was based on water permeability, solute selectivity, and operational robustness, while commercial readiness was based on known or anticipated material costs, scalability (for large scale water treatment applications), and compatibility with existing manufacturing infrastructure. Overall, bio-inspired membranes are farthest from commercial reality, but offer the most promise for performance enhancements; however, nanocomposite membranes offering significant performance enhancements are already commercially available. Zeolitic and catalytic membranes appear reasonably far from commercial reality and offer small to moderate performance enhancements. The ranking of each membrane nanotechnology is discussed along with the key commercialization hurdles for each membrane nanotechnology. © 2011 The Royal Society of Chemistry.

  20. Infrasonic backpulsed membrane cleaning of micro- and ...

    African Journals Online (AJOL)

    Membrane fouling is universally considered to be one of the most critical problems in the wider application of membrane filtration. In this research microfiltration and ultrafiltration membranes were fouled during a cross-flow filtration process, using yeast and alumina suspensions in a flat cell. Infrasonic backpulsing directly ...

  1. Atomistic Monte Carlo simulation of lipid membranes

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Sklenar, Heinz

    2014-01-01

    Biological membranes are complex assemblies of many different molecules of which analysis demands a variety of experimental and computational approaches. In this article, we explain challenges and advantages of atomistic Monte Carlo (MC) simulation of lipid membranes. We provide an introduction...... of local-move MC methods in combination with molecular dynamics simulations, for example, for studying multi-component lipid membranes containing cholesterol....

  2. Membranes for Environmentally Friendly Energy Processes

    Science.gov (United States)

    He, Xuezhong; Hägg, May-Britt

    2012-01-01

    Membrane separation systems require no or very little chemicals compared to standard unit operations. They are also easy to scale up, energy efficient, and already widely used in various gas and liquid separation processes. Different types of membranes such as common polymers, microporous organic polymers, fixed-site-carrier membranes, mixed matrix membranes, carbon membranes as well as inorganic membranes have been investigated for CO2 capture/removal and other energy processes in the last two decades. The aim of this work is to review the membrane systems applied in different energy processes, such as post-combustion, pre-combustion, oxyfuel combustion, natural gas sweetening, biogas upgrading, hydrogen production, volatile organic compounds (VOC) recovery and pressure retarded osmosis for power generation. Although different membranes could probably be used in a specific separation process, choosing a suitable membrane material will mainly depend on the membrane permeance and selectivity, process conditions (e.g., operating pressure, temperature) and the impurities in a gas stream (such as SO2, NOx, H2S, etc.). Moreover, process design and the challenges relevant to a membrane system are also being discussed to illustrate the membrane process feasibility for a specific application based on process simulation and economic cost estimation. PMID:24958426

  3. Activation of interfacial enzymes at membrane surfaces

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Andresen, Thomas Lars; Halperin, Avi

    2006-01-01

    A host of water-soluble enzymes are active at membrane surfaces and in association with membranes. Some of these enzymes are involved in signalling and in modification and remodelling of the membranes. A special class of enzymes, the phospholipases, and in particular secretory phospholipase A2 (s...

  4. hydrophobic silica membranes for gas separation

    NARCIS (Netherlands)

    de Vos, R.M.; Maier, Wilhelm F.; Verweij, H.

    1999-01-01

    The synthesis and properties of hydrophobic silica membranes are described. These membranes show very high gas permeance for small molecules, such as H2, CO2, N2, O2, and CH4, and permselectivities of 20–50 for these gases with respect to SF6 and larger alkanes like C3H8 and i-C4H10. The membranes

  5. Characterization of clean and fouled ultrafiltration membranes

    NARCIS (Netherlands)

    Hanemaaijer, J.H.; Robbertsen, T.; van den Boomgaard, Anthonie; Olieman, C.; Both, P.; Schmidt, D.G.

    1988-01-01

    Much research into the fundamentals of membrane formation and separation has been performed in order to improve the efficiency of the manufacture of ultrafiltration membranes. Determination of the membrane characteristics is a key problem in these investigations. In this paper, we report on a study

  6. Proteins and Peptides in Biomimetic Polymeric Membranes

    DEFF Research Database (Denmark)

    Perez, Alfredo Gonzalez

    2013-01-01

    This chapter discusses recent advances and the main advantages of block copolymers for functional membrane protein reconstitution in biomimetic polymeric membranes. A rational approach to the reconstitution of membrane proteins in a functional form can be addressed by a more holistic view by using...

  7. Transport through track etched polymeric blend membrane

    Indian Academy of Sciences (India)

    Polymer blends of polycarbonate (PC) and polysulphone (PSF) having thickness, 27 m, are prepared by solution cast method. The transport properties of pores in a blend membrane are examined. The pores were produced in this membrane by a track etching technique. For this purpose, a thin polymer membrane was ...

  8. Membranes for Environmentally Friendly Energy Processes

    Directory of Open Access Journals (Sweden)

    Xuezhong He

    2012-10-01

    Full Text Available Membrane separation systems require no or very little chemicals compared to standard unit operations. They are also easy to scale up, energy efficient, and already widely used in various gas and liquid separation processes. Different types of membranes such as common polymers, microporous organic polymers, fixed-site-carrier membranes, mixed matrix membranes, carbon membranes as well as inorganic membranes have been investigated for CO2 capture/removal and other energy processes in the last two decades. The aim of this work is to review the membrane systems applied in different energy processes, such as post-combustion, pre-combustion, oxyfuel combustion, natural gas sweetening, biogas upgrading, hydrogen production, volatile organic compounds (VOC recovery and pressure retarded osmosis for power generation. Although different membranes could probably be used in a specific separation process, choosing a suitable membrane material will mainly depend on the membrane permeance and selectivity, process conditions (e.g., operating pressure, temperature and the impurities in a gas stream (such as SO2, NOx, H2S, etc.. Moreover, process design and the challenges relevant to a membrane system are also being discussed to illustrate the membrane process feasibility for a specific application based on process simulation and economic cost estimation.

  9. Solar driven membrane pervaporation for desalination processes

    NARCIS (Netherlands)

    Zwijnenberg, Harmen Jan; Koops, G.H.; Wessling, Matthias

    2005-01-01

    We describe details of a solar driven pervaporation process for the production of desalinated water from highly contaminated waters. The membrane material is a polyetheramide-based polymer film of 40 ¿m thickness. This Solar Dew® membrane is used in a tubular configuration in a direct solar membrane

  10. Recycling from endosomes to the plasma membrane

    NARCIS (Netherlands)

    Dam, E.M. van

    2001-01-01

    Summary V Chapter?Summary Many membrane proteins are, after endocytic uptake, efficiently recycled back to the plasma membrane. The aim of the studies presented in this thesis was to determine pathways and molecular mechanisms that are involved in recycling. Plasma membrane-derived clathrin-coated

  11. Lipid organization of the plasma membrane

    NARCIS (Netherlands)

    Ingólfsson, Helgi I; Melo, Manuel N; van Eerden, Floris J; Arnarez, Clément; Lopez, Cesar A; Wassenaar, Tsjerk A; Periole, Xavier; de Vries, Alex H; Tieleman, D Peter; Marrink, Siewert J

    2014-01-01

    The detailed organization of cellular membranes remains rather elusive. Based on large-scale molecular dynamics simulations, we provide a high-resolution view of the lipid organization of a plasma membrane at an unprecedented level of complexity. Our plasma membrane model consists of 63 different

  12. One Step Membrane Filtration : A fundamental study

    NARCIS (Netherlands)

    Haidari, A.H.

    2017-01-01

    This study focuses on spiral-wound membrane (SWM) modules, which are the most common commercially available membrane modules for reverse osmosis (RO) and nanofiltration (NF). While RO membranes can remove almost all kinds of substances from the feed water, they are usually equipped with pretreatment

  13. Biofouling of spiral wound membrane systems

    NARCIS (Netherlands)

    Vrouwenvelder, J.S.

    2009-01-01

    Biofouling of spiral wound membrane systems High quality drinking water can be produced with membrane filtration processes like reverse osmosis (RO) and nanofiltration (NF). Because the global demand for fresh clean water is increasing, these membrane technologies will increase in importance in the

  14. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Dutch researchers from the TN0 Institute have developed a technique to carry out gas-liquid contacting operations using hollow fibre membranes in combination with an absorption liquid. The method known as membrane gas absorption, aims to combine the advantages of membrane technology (compactness,

  15. Focus on Membrane Differentiation and Membrane Domains in the Prokaryotic Cell

    NARCIS (Netherlands)

    Boekema, Egbert J.; Scheffers, Dirk-Jan; van Bezouwen, Laura S.; Bolhuis, Henk; Folea, I. Mihaela

    2013-01-01

    A summary is presented of membrane differentiation in the prokaryotic cell, with an emphasis on the organization of proteins in the plasma/cell membrane. Many species belonging to the Eubacteria and Archaea have special membrane domains and/or membrane proliferation, which are vital for different

  16. Structure and properties of cell membranes. Volume 3: Methodology and properties of membranes

    International Nuclear Information System (INIS)

    Benga, G.

    1985-01-01

    This book covers the topics: Quantum chemical approach to study the mechanisms of proton translocation across membranes through protein molecules; monomolecular films as biomembrane models; planar lipid bilayers in relation to biomembranes; relation of liposomes to cell membranes; reconstitution of membrane transport systems; structure-function relationships in cell membranes as revealed by X-ray techniques; structure-function relationships in cell membranes as revealed by spin labeling ESR; structure and dynamics of cell membranes as revealed by NMR techniques; the effect of dietary lipids on the composition and properties of biological membranes and index

  17. Axisymmetric finite deformation membrane problems

    Energy Technology Data Exchange (ETDEWEB)

    Feng, W.W.

    1980-12-12

    Many biomechanic problems involve the analysis of finite deformation axisymmetric membranes. This paper presents the general formulation for solving a class of axisymmetric membrane problems. The material nonlinearity, as well as the geometric nonlinearity, is considered. Two methods are presented to solve these problems. The first method is solving a set of differential equilibrium equations. The governing equations are reduced to three first-order ordinary-differential equations with explicit derivatives. The second method is the Ritz method where a general potential energy functional valid for all axisymmetric deformed positions is presented. The geometric admissible functions that govern the deformed configuration are written in terms of a series with unknown coefficients. These unknown coefficients are determined by the minimum potential energy principle that of all geometric admissible deformed configurations, the equilibrium configuration minimizes the potential energy. Some examples are presented. A comparison between these two methods is mentioned.

  18. Energy efficiency in membrane bioreactors.

    Science.gov (United States)

    Barillon, B; Martin Ruel, S; Langlais, C; Lazarova, V

    2013-01-01

    Energy consumption remains the key factor for the optimisation of the performance of membrane bioreactors (MBRs). This paper presents the results of the detailed energy audits of six full-scale MBRs operated by Suez Environnement in France, Spain and the USA based on on-site energy measurement and analysis of plant operation parameters and treatment performance. Specific energy consumption is compared for two different MBR configurations (flat sheet and hollow fibre membranes) and for plants with different design, loads and operation parameters. The aim of this project was to understand how the energy is consumed in MBR facilities and under which operating conditions, in order to finally provide guidelines and recommended practices for optimisation of MBR operation and design to reduce energy consumption and environmental impacts.

  19. Enhancement of the Computational Efficiency of Membrane Computing Models

    National Research Council Canada - National Science Library

    Das, Digendra K

    2007-01-01

    .... Membrane computing consists of cell-like membranes placed inside a unique skin membrane. In regions delimited by a membrane structure, cells are placed in multisets of objects which evolve according to evolution rules associated with the regions...

  20. Living Membranes as Environmental Detectors

    Science.gov (United States)

    2016-02-19

    the original proposal. Working with the bacterial cellulose “ Living Membrane” system, we have addressed the major design and structural impediments...cloning of the cellulose genetic machinery. We have also identified potential future directions to optimize and 1. REPORT DATE (DD-MM-YYYY) 4. TITLE...Oct-2011 30-Sep-2015 Approved for Public Release; Distribution Unlimited Final Report: Living Membranes as Environmental Detectors The views, opinions

  1. Membrane technology costs and me.

    Science.gov (United States)

    Judd, S J

    2017-10-01

    A reflection of the place cost analysis holds in membrane process technology research and development is provided. The review encompassed two membrane processes and applications: (a) reverse osmosis (RO) for seawater desalination, and (b) membrane bioreactor (MBR) technology for wastewater treatment. The cost analysis undertaken extended to (i) the determination of operating expenditure (OPEX) trends using simple analytical expressions, (ii) the subsequent estimation of the sensitivity of OPEX to individual system parameters, and (iii) published data on CAPEX for individual full-scale installations or from cost analyses. An appraisal of the peer-reviewed literature through a survey of a leading scientific database was also carried out. This bibliometric analysis was based on authors' keywords; it aimed to establish the profile of process cost for each of the two applications when compared with other popular research topics. The OPEX analysis, ostensibly through a consideration of specific energy demand in kWh per m 3 permeate, revealed it to relate primarily to hydrodynamics in the case of RO, and to both membrane fouling and air scouring for MBRs. The bibliometric analysis of research trends revealed a marked difference in emphasis on cost aspects between the two research areas, with the focus on cost specifically being 16 times greater for RO desalination of seawater than MBR treatment of wastewater. MBR research appears to be dominated by fouling and foulant characterisation, making up almost a quarter of all studies, notwithstanding evidence from practitioners that other process parameters are as important in determining MBR process OPEX and operability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Golgi GRASPs: moonlighting membrane tethers

    Directory of Open Access Journals (Sweden)

    Jarvela T

    2012-05-01

    Full Text Available Timothy Jarvela, Adam D LinstedtDepartment of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USAAbstract: The identification of mammalian Golgi reassembly stacking proteins (GRASPs 15 years ago was followed by experiments implicating them in diverse functions, including two differing structural roles in Golgi biogenesis and at least two distinct roles in the secretion of proteins. GRASP55 and GRASP65 are localized to cis and medial/trans Golgi cisternae, respectively. They are both required for stacking of Golgi membranes in a Golgi reassembly assay. Depletion of either GRASP from cultured cells prevents the linking of Golgi membranes into their normal ribbon-like network. While GRASPs are not required for transport of secretory cargo per se, they are required for ER-to-Golgi transport of certain specific cargo, such as those containing a C-terminal valine motif. Surprisingly, GRASPs also promote secretion of cargo by the so-called unconventional secretory pathway, which bypasses the Golgi apparatus where the GRASPs reside. Furthermore, regulation of GRASP activity is now recognized for its connections to cell cycle control, development, and disease. Underlying these diverse activities is the structurally conserved N-terminal GRASP domain whose crystal structure was recently determined. It consists of a tandem array of atypical PSD95–DlgA–Zo–1 (PDZ domains, which are well-known protein–protein interaction motifs. The GRASP PDZ domains are used to localize the proteins to the Golgi as well as GRASP-mediated membrane tethering and cargo interactions. These activities are regulated, in part, by phosphorylation of the large unstructured C-terminal domain.Keywords: GRASP, review, membrane, tether, PDZ domain, secretory chaperone, unconventional secretion

  3. Fetal membrane healing after spontaneous and iatrogenic membrane rupture: A review of current evidence

    OpenAIRE

    Devlieger, R.; Millar, L. K.; Bryant-Greenwood, G.; Lewi, L.; Deprest, J. A.

    2006-01-01

    In view of the important protective role of the fetal membranes, wound sealing, tissue regeneration, or wound healing could be life saving in cases of preterm premature rupture of the membranes. Although many investigators are studying the causes of preterm premature rupture of membranes, the emphasis has not been on the wound healing capacity of the fetal membranes. In this review, the relevant literature on the pathophysiologic condition that leads to preterm premature rupture of membranes ...

  4. In-membrane micro fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Omosebi, Ayokunle; Besser, Ronald

    2016-09-06

    An in-membrane micro fuel cell comprises an electrically-insulating membrane that is permissive to the flow of cations, such as protons, and a pair of electrodes deposited on channels formed in the membrane. The channels are arranged as conduits for fluids, and define a membrane ridge between the channels. The electrodes are porous and include catalysts for promoting the liberation of a proton and an electron from a chemical species and/or or the recombination of a proton and an electron with a chemical specie. The fuel cell may be provided a biosensor, an electrochemical sensor, a microfluidic device, or other microscale devices fabricated in the fuel cell membrane.

  5. Adsorption of amylase enzyme on ultrafiltration membranes

    DEFF Research Database (Denmark)

    Beier, Søren; Enevoldsen, Ann Dorrit; Kontogeorgis, Georgios

    2007-01-01

    A method to measure the static adsorption on membrane surfaces has been developed and described. The static adsorption of an amylase-F has been measured on two different ultrafiltration membranes, both with a cut-off value of 10 kDa (a PES membrane and the ETNA10PP membrane, which is a surface-mo...... is independent of the membrane type. At higher concentrations of enzyme, concentration polarization effects can not be neglected. Therefore stagnant film theory and the osmotic pressure model can describe the dependency between flux and bulk concentration....

  6. MECHANISM OF LIQUID MEMBRANES AND APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Filiz Nuran ACAR

    2002-02-01

    Full Text Available It has been considerably studied on the recycling of waste materials in the source besides of wastewater treatment in the last years. It has been important developments on the using of semiconductor membranes in the recycling of toxic materials such as heavy metals, intensifying the environment protection measures especially in the west countries. Wastewater treatment has been achieved with liquid membranes as it has been achieved with polymeric membrane systems such as ultrafiltration, microfiltration, electrodialysis. At the same time, liquid membranes are used for removal of metal ions in hydrometallurgy. Liquid membranes are also used in biotechnology, medical areas and gas separation process.

  7. Liquid crystal model of membrane flexoelectricity.

    Science.gov (United States)

    Rey, Alejandro D

    2006-07-01

    An interfacial liquid crystal model is formulated and used to derive a membrane shape equation that takes into account pressure, tension, bending, torsion, and flexoelectric forces. Flexoelectricity introduces electric field-induced curvature and is of relevance to the study and characterization of biological membranes. It is shown that flexoelectricity renormalizes the membrane mechanical tension, shear, and bending effects, and hence it offers diverse pathways to manipulate the membrane's shape. The derived electroelastic shape equation provides systematic guidance on how to use electric fields in membrane studies.

  8. Inflation and Instability of a Polymeric Membrane

    DEFF Research Database (Denmark)

    Neergaard, Jesper; Hassager, Ole

    1999-01-01

    We consider the inflation of an axisymmetric polymeric membrane. Some membranes composed of viscoelastic materials described by a Mooney-Rivlin model show a monotone increasingpressure during inflation. These materialsdevelop a homogeneous membrane thickness in agreement with the Considere......-Pearson condition.Molecularly based models such as the neo-Hookean, Doi-Edwards or Tom-Pom model exhibit a pressure maximum when inflated. Membranes described by these models develop local thinning which may lead to bursting in finite time. Chain branching is found to be a stabilizing factor for a polymer membrane...... undergoing inflation....

  9. Ocean thermocline driven membrane distillation process

    KAUST Repository

    Francis, Lijo

    2017-07-20

    Systems and methods using membrane distillation are provided for desalinating water, for example for the production of potable water, to address freshwater requirements. In an aspect the systems and methods do not require applying an external heat source, or the energy cost of the heating source, to heat the feed stream to the membrane. In an aspect, the sensible heat present in surface seawater is used for the heat energy for the warm stream fed to the membrane, and deep seawater is used as the cold/coolant feed to the membrane to provide the needed temperature gradient or differential across the membrane.

  10. Inflation and Instability of a Polymeric Membrane

    DEFF Research Database (Denmark)

    Neergaard, Jesper; Hassager, Ole

    1999-01-01

    We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane. The polymeric materialis described by an arbitrary combination of a viscoelastic and a purely viscous component to the stress. Some viscoelastic materials described by a Mooney......-Rivlin model show a monotone increasingpressure during inflation of a spherical membrane. These materials develop a homogeneous membrane thickness in agreement with the Considere-Pearson condition. Molecularly based models such as the neo-Hookean, Doi-Edwards or Tom-Pom model show a pressure maximum when...... inflated. Membranesdescribed by these models develop a local thinning of the membrane which may lead to bursting in finite time....

  11. Carbon membranes - current progress and future prospects

    International Nuclear Information System (INIS)

    Tennison, St.; Arnott, K.; Richter, H.

    2007-01-01

    The future use of nano-porous gas separation membranes will be dependent on significant reductions in the membrane and module costs, improvements in production methods to allow better reproducibility, ability to scale up production and improved performance and understanding of the mode of operation of the membrane systems. New approaches to ceramic supported carbon membranes could offer solutions to these problems. Whilst the performance characteristics underline the limitations of these membranes they also show where specific process opportunities might be accessible particularly in environmental and high temperature separations. (authors)

  12. Black holes: the membrane paradigm

    International Nuclear Information System (INIS)

    Thorne, K.S.; Price, R.H.; Macdonald, D.A.

    1986-01-01

    The physics of black holes is explored in terms of a membrane paradigm which treats the event horizon as a two-dimensional membrane embedded in three-dimensional space. A 3+1 formalism is used to split Schwarzschild space-time and the laws of physics outside a nonrotating hole, which permits treatment of the atmosphere in terms of the physical properties of thin slices. The model is applied to perturbed slowly or rapidly rotating and nonrotating holes, and to quantify the electric and magnetic fields and eddy currents passing through a membrane surface which represents a stretched horizon. Features of tidal gravitational fields in the vicinity of the horizon, quasars and active galalctic nuclei, the alignment of jets perpendicular to accretion disks, and the effects of black holes at the center of ellipsoidal star clusters are investigated. Attention is also given to a black hole in a binary system and the interactions of black holes with matter that is either near or very far from the event horizon. Finally, a statistical mechanics treatment is used to derive a second law of thermodynamics for a perfectly thermal atmosphere of a black hole

  13. Manufacturing microporous membrane by polymerisation

    International Nuclear Information System (INIS)

    Tanny, G.B.

    1984-01-01

    The starting materials for the practice of the present invention are (1) one or more organic monomers or oligomers which upon irradiation very rapidly undergo a polymerization reaction to form a solid polymer; and (2) a liquid vehicle in which the one or more organic monomers or oligomers are soluble but in which the polymer formed is insoluble. For the manufacture of microporous membrane in accordance with the invention the monomers or oligomers are dissolved in the liquid vehicle, the resulting solution is formed into a thin layer, and the thin layer of the solution is then irradiated as with ultraviolet or electron beam radiation whereupon the rapid polymerization reaction immediately ensues and the polymer formed immediately segregates from the vehicle thereby resulting in microporous membrane from which the vehicle can be removed as by evaporation or washing. Because the radiation-induced polymerization reaction and the segregation of the polymer formed are so rapid, the membrane formed has cells and communications therebetween of very small dimensions thereby providing the microporous structure. Where ultra-violet radiation is used the solution also includes a photo-initiator. (author)

  14. Arsenic Removal by Liquid Membranes

    Directory of Open Access Journals (Sweden)

    Tiziana Marino

    2015-03-01

    Full Text Available Water contamination with harmful arsenic compounds represents one of the most serious calamities of the last two centuries. Natural occurrence of the toxic metal has been revealed recently for 21 countries worldwide; the risk of arsenic intoxication is particularly high in Bangladesh and India but recently also Europe is facing similar problem. Liquid membranes (LMs look like a promising alternative to the existing removal processes, showing numerous advantages in terms of energy consumption, efficiency, selectivity, and operational costs. The development of different LM configurations has been a matter of investigation by several researching groups, especially for the removal of As(III and As(V from aqueous solutions. Most of these LM systems are based on the use of phosphine oxides as carriers, when the metal removal is from sulfuric acid media. Particularly promising for water treatment is the hollow fiber supported liquid membrane (HFSLM configuration, which offers high selectivity, easy transport of the targeted metal ions, large surface area, and non-stop flow process. The choice of organic extractant(s plays an essential role in the efficiency of the arsenic removal. Emulsion liquid membrane (ELM systems have not been extensively investigated so far, although encouraging results have started to appear in the literature. For such LM configuration, the most relevant step toward efficiency is the choice of the surfactant type and its concentration.

  15. AMNIOTIC MEMBRANE TRANSPLANTATION FOR KERATITIS.

    Directory of Open Access Journals (Sweden)

    Snezhana Murgova

    2015-06-01

    Full Text Available Keratitis without proper management tends to perforate the cornea, resulting in severe adverse consequences. In recent studies, amniotic membrane is reported to have anti-inflammatory effect and promote wound healing of corneal ulcer. Purpose: To report on the efficacy of permanent amniotic membrane transplantation (AMT in the treatment of keratitis. Case report: A 58-year-old man with severe keratitis in both eyes caused by long term administration of topical anesthetic (alcaine for electric ophthalmia. Single layer of amniotic membrane (AM was placed on the defect and secured to the limbus with interrupted 10-0 nylon sutures. A bandage contact lens was applied on the AM. Postoperative medication included topical antibiotic, artificial tears and mydriatic. Three months later corticosteroid was included. There was an immediate decrease of patient’s pain after surgery. Complete epithelialization was noted after 1 month. Conclusion: AMT is an alternative adjunctive method of treatment of keratitis; it promotes epithelialization process, decreased inflammation, corneal haze and neovascularization.

  16. Cell membrane structures during exocytosis.

    Science.gov (United States)

    Savigny, Pascale; Evans, John; McGrath, Kathryn M

    2007-08-01

    Exocytosis is a key biological process that controls the neurotransmission and release of hormones from cells. In endocrine cells, hormones are packed into secretory vesicles and released into the extracellular environment via openings in the plasma membrane, a few hundred nanometers wide, which form as a result of fusion of the membranes of the granule and cell. The complex processes and dynamics that result in the formation of the fusion pore, as well as its structure, remain scantly understood. A number of different exocytosis mechanisms have been postulated. Furthermore, the possibility exists that several mechanisms occur simultaneously. We present here an investigation of the cell membrane dynamics during exocytosis in anterior pituitary cells, especially gonadotropes, which secrete LH, a hormone central to ovulation. Gonadotrope enrichment was achieved using immunolabeled magnetic nanobeads. Three complementary imaging techniques were used to realize a fine structure study of the dynamics of the exocytosis-like sites occurring during secretion. Living pituitary and gonadotrope-enriched cells were imaged with atomic force microscopy, as well as cells that had been fixed to obtain better resolution. Atomic force microscopy, along with scanning and transmission electron microscopy, studies of these cells revealed that there are at least two different site configurations: simple single fusion pores and a complex association of pores consisting of a simple primary site combined with secondary attachments.

  17. Mechano-capacitive properties of polarized membranes.

    Science.gov (United States)

    Mosgaard, Lars D; Zecchi, Karis A; Heimburg, Thomas

    2015-10-28

    Biological membranes are capacitors that can be charged by applying a field across the membrane. The charges on the capacitor exert a force on the membrane that leads to electrostriction, i.e. a thinning of the membrane. Since the force is quadratic in voltage, negative and positive voltage have an identical influence on the physics of symmetric membranes. However, this is not the case for a membrane with an asymmetry leading to a permanent electric polarization. Positive and negative voltages of identical magnitude lead to different properties. Such an asymmetry can originate from a lipid composition that is different on the two monolayers of the membrane, or from membrane curvature. The latter effect is called 'flexoelectricity'. As a consequence of permanent polarization, the membrane capacitor is discharged at a voltage different from zero. This leads to interesting electrical phenomena such as outward or inward rectification of membrane permeability. Here, we introduce a generalized theoretical framework, that treats capacitance, polarization, flexoelectricity, piezoelectricity and thermoelectricity in the same language. We show applications to electrostriction, membrane permeability and piezoelectricity and thermoelectricity close to melting transitions, where such effects are especially pronounced.

  18. Genistein Modified Polymer Blends for Hemodialysis Membranes

    Science.gov (United States)

    Chang, Teng; Kyu, Thein; Define, Linda; Alexander, Thomas

    2012-02-01

    A soybean-derived phytochemical called genistein was used as a modifying agent to polyether sulfone/polyvinyl pyrrolidone (PES/PVP) blends to produce multi-functional hemodialysis membranes. With the aid of phase diagrams of PES/PVP/genistein blends, asymmetric porous membranes were fabricated by coagulating in non-solvent. Both unmodified and genistein modified PES/PVP membranes were shown to be non-cytotoxic to the blood cells. Unmodified PES/PVP membranes were found to reduce reactive oxygen species (ROS) levels, whereas the genistein modified membranes exhibited suppression for ˜60% of the ROS levels. Also, the genistein modified membranes revealed significant suppression of pro-inflammatory cytokines: IL-1β, IL-6, and TNF-α. Moreover, addition of PVP to PES showed the reduced trend of platelet adhesion and then leveled off. However, the modified membranes exhibited suppression of platelet adhesion at low genistein loading, but beyond 15 wt%, the platelet adhesion level rised up.

  19. Composite perfluorohydrocarbon membranes, their preparation and use

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yong; Bikson, Benjamin

    2017-04-04

    Composite porous hydrophobic membranes are prepared by forming a perfluorohydrocarbon layer on the surface of a preformed porous polymeric substrate. The substrate can be formed from poly (aryl ether ketone) and a perfluorohydrocarbon layer can be chemically grafted to the surface of the substrate. The membranes can be utilized for a broad range of fluid separations, such as microfiltration, nanofiltration, ultrafiltration as membrane contactors for membrane distillation and for degassing and dewatering of fluids. The membranes can further contain a dense ultra-thin perfluorohydrocarbon layer superimposed on the porous poly (aryl ether ketone) substrate and can be utilized as membrane contactors or as gas separation. membranes for natural gas treatment and gas dehydration.

  20. Photo-switchable membrane and method

    Science.gov (United States)

    Marshall, Kenneth L; Glowacki, Eric

    2013-05-07

    Switchable gas permeation membranes in which a photo-switchable low-molecular-weight liquid crystalline (LC) material acts as the active element, and a method of making such membranes. Different LC eutectic mixtures were doped with mesogenic azo dyes and infused into track-etched porous membranes with regular cylindrical pores. Photo-induced isothermal phase changes in the imbibed mesogenic material afforded large, reversible changes in the permeability of the photo-switchable membrane to nitrogen. For example, membranes imbibed with a photo-switchable cyanobiphenyl LC material demonstrated low permeability in the nematic state, while the photo-generated isotropic state demonstrated a 16.times.-greater sorption coefficient. Both states obey a high linear sorption behavior in accordance with Henry's Law. In contrast, membranes imbibed with a photo-switchable phenyl benzoate LC material showed the opposite permeability behavior to the biphenyl-imbibed membrane, along with nonlinear sorption behavior.

  1. Ion transport membrane module and vessel system

    Energy Technology Data Exchange (ETDEWEB)

    Stein, VanEric Edward; Carolan, Michael Francis; Chen, Christopher M.; Armstrong, Phillip Andrew; Wahle, Harold W.; Ohrn, Theodore R.; Kneidel, Kurt E.; Rackers, Keith Gerard; Blake, James Erik; Nataraj, Shankar; van Doorn, Rene Hendrik Elias; Wilson, Merrill Anderson

    2007-02-20

    An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel. The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

  2. Ion transport membrane module and vessel system

    Energy Technology Data Exchange (ETDEWEB)

    Stein, VanEric Edward [Allentown, PA; Carolan, Michael Francis [Allentown, PA; Chen, Christopher M [Allentown, PA; Armstrong, Phillip Andrew [Orefield, PA; Wahle, Harold W [North Canton, OH; Ohrn, Theodore R [Alliance, OH; Kneidel, Kurt E [Alliance, OH; Rackers, Keith Gerard [Louisville, OH; Blake, James Erik [Uniontown, OH; Nataraj, Shankar [Allentown, PA; Van Doorn, Rene Hendrik Elias (Obersulm-Willsbach, DE); Wilson, Merrill Anderson [West Jordan, UT

    2012-02-14

    An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel. The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

  3. Ion transport membrane module and vessel system

    Energy Technology Data Exchange (ETDEWEB)

    Stein, VanEric Edward [Allentown, PA; Carolan, Michael Francis [Allentown, PA; Chen, Christopher M [Allentown, PA; Armstrong, Phillip Andrew [Orefield, PA; Wahle, Harold W [North Canton, OH; Ohrn, Theodore R [Alliance, OH; Kneidel, Kurt E [Alliance, OH; Rackers, Keith Gerard [Louisville, OH; Blake, James Erik [Uniontown, OH; Nataraj, Shankar [Allentown, PA; van Doorn, Rene Hendrik Elias (Obersulm-Willsbach, DE); Wilson, Merrill Anderson [West Jordan, UT

    2008-02-26

    An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel.The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

  4. Biomimetic aquaporin membranes coming of age

    DEFF Research Database (Denmark)

    Tang, Chuyang; Wang, Zhining; Petrinić, Irena

    2015-01-01

    Membrane processes have been widely used for water purification because of their high stability, efficiency, low energy requirement and ease of operation. Traditional desalting membranes are mostly dense polymeric films with a "trade off" effect between permeability and selectivity. Biological...... membranes, on the other hand, can perform transport in some cases with exceptional flux and rejection properties. In particular the discovery of selective water channel proteins - aquaporins - has prompted interest in using these proteins as building blocks for new types of membranes. The major challenge...... in developing an aquaporin-based membrane technology stems from the fact that the aquaporin protein spans a membrane only a few nanometers thick. Such ultrathin membranes will not be able to withstand any substantial pressures, nor being industrially scalable without supporting structures. Incorporating...

  5. Robust High Performance Aquaporin based Biomimetic Membranes

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus; Zhao, Yichun; Qiu, C.

    2013-01-01

    Aquaporins are water channel proteins with high water permeability and solute rejection, which makes them promising for preparing high-performance biomimetic membranes. Despite the growing interest in aquaporin-based biomimetic membranes (ABMs), it is challenging to produce robust and defect...... on top of a support membrane. Control membranes, either without aquaporins or with the inactive AqpZ R189A mutant aquaporin served as controls. The separation performance of the membranes was evaluated by cross-flow forward osmosis (FO) and reverse osmosis (RO) tests. In RO the ABM achieved a water...... permeability of ~ 4 L/(m2 h bar) with a NaCl rejection > 97% at an applied hydraulic pressure of 5 bar. The water permeability was ~40% higher compared to a commercial brackish water RO membrane (BW30) and an order of magnitude higher compared to a seawater RO membrane (SW30HR). In FO, the ABMs had > 90...

  6. Polymeric molecular sieve membranes for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng; Qiao, Zhenan; Chai, Songhai

    2017-08-15

    A porous polymer membrane useful in gas separation, the porous polymer membrane comprising a polymeric structure having crosslinked aromatic groups and a hierarchical porosity in which micropores having a pore size less than 2 nm are present at least in an outer layer of the porous polymer membrane, and macropores having a pore size of over 50 nm are present at least in an inner layer of the porous polymer membrane. Also described are methods for producing the porous polymer membrane in which a non-porous polymer membrane containing aromatic rings is subjected to a Friedel-Crafts crosslinking reaction in which a crosslinking molecule crosslinks the aromatic rings in the presence of a Friedel-Crafts catalyst and organic solvent under sufficiently elevated temperature, as well as methods for using the porous polymer membranes for gas or liquid separation, filtration, or purification.

  7. Reverse osmosis membrane allows in situ regeneration

    International Nuclear Information System (INIS)

    Bonhomme, N.; Menjeaud, C.; Poyet, C.

    1989-01-01

    The use of mineral membranes on metallic supports has provided a novel solution to the problem of filtration by the reverse osmosis process. A new reverse osmosis membrane is described which is capable of resisting high operational temperatures (120 0 C), fluctuations in pH(3 to 12) and high pressure (100 bar), as well as significant chlorine concentrations. In addition, the membrane can be regenerated in-situ on the same porous metal support. Numerous membranes can thus be used over the multi-year life of the porous support. Moreover, accidental damage to the membrane is of no great consequence as the membrane itself can be easily replaced. The life of the installation can thus be extended and the overall cost of filtration reduced. The membrane's various applications include water and effluent treatment in the nuclear power industry. (author)

  8. Membrane-based technologies for biogas separations.

    Science.gov (United States)

    Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

    2010-02-01

    Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

  9. New Polymeric Membranes for Organic Solvent Nanofiltration

    KAUST Repository

    Aburabie, Jamaliah

    2017-05-01

    The focus of this dissertation was the development, synthesis and modification of polymers for the preparation of membranes for organic solvent nanofiltration. High chemical stability in a wide range of solvents was a key requirement. Membranes prepared from synthesized polymers as well as from commercial polymers were designed and chemically modified to reach OSN requirements. A solvent stable thin-film composite (TFC) membrane is reported, which is fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate. The membranes exhibited high fluxes towards solvents like THF, DMF and DMSO ranging around 20 L/m2 h at 5 bar with a MWCO of around 1000 g/mol. Ultrafiltration PTSC membranes were prepared by non-solvent induced phase separation and crosslinked with GPTMS. The crosslinking reaction was responsible for the formation of an inorganic-type-network that tuned the membrane pore size. The crosslinked membranes acquired high solvent stability in DMSO, DMF and THF with a MWCO above 1300 g/mol. Reaction Induced Phase Separation (RIPS) was introduced as a new method for the preparation of skinned asymmetric membranes. These membranes have two distinctive layers with different morphologies both from the same polymer. The top dense layer is composed of chemically crosslinked polymer chains while the bottom layer is a porous structure formed by non-crosslinked polymer chains. Such membranes were tested for vitamin B12 in solvents after either crosslinking the support or dissolving the support and fixing the freestanding membrane on alumina. Pebax® 1657 was utilized for the preparation of composite membranes by simple coating. Porous PAN membranes were coated with Pebax® 1657 which was then crosslinked using TDI. Crosslinked Pebax® membranes show high stability towards ethanol, propanol and acetone. The membranes were also stable in DMF once crosslinked PAN supports were used. Sodium alginate polymer was investigated for the preparation of thin film composite

  10. Methods of amniotic membrane fixation in ocular amniotic membrane surgeries

    Directory of Open Access Journals (Sweden)

    Shu-Rong Wang

    2016-05-01

    Full Text Available Various ocular surface disorders like alkali burns and corneal ulcers can all cause damage to the cornea and conjunctiva, and often induce corneal neovascularization(CNVthat affects the visual function. However, amniotic membranes(AMcan promote the rapid epithelization of acute injured corneas and conjunctiva defects, diminish scarring, and perform anti-inflammatory effect. Therefore, AM has been widely used in ocular surface reconstructions and treatment of CNV. But the key problem is how to fix the AM. Only ensuring the adhesive time and cover area with convenient operation and little stimulation can achieve the best curative effect. This article reviews the methods of AM fixation in AM patch technique.

  11. Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

    International Nuclear Information System (INIS)

    Li Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

    2005-01-01

    Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance

  12. Evaluation method of membrane performance in membrane distillation process for seawater desalination.

    Science.gov (United States)

    Chung, Seungjoon; Seo, Chang Duck; Choi, Jae-Hoon; Chung, Jinwook

    2014-01-01

    Membrane distillation (MD) is an emerging desalination technology as an energy-saving alternative to conventional distillation and reverse osmosis method. The selection of appropriate membrane is a prerequisite for the design of an optimized MD process. We proposed a simple approximation method to evaluate the performance of membranes for MD process. Three hollow fibre-type commercial membranes with different thicknesses and pore sizes were tested. Experimental results showed that one membrane was advantageous due to the highest flux, whereas another membrane was due to the lowest feed temperature drop. Regression analyses and multi-stage calculations were used to account for the trade-offeffects of flux and feed temperature drop. The most desirable membrane was selected from tested membranes in terms of the mean flux in a multi-stage process. This method would be useful for the selection of the membranes without complicated simulation techniques.

  13. The Effect of Membrane Material and Surface Pore Size on the Fouling Properties of Submerged Membranes

    Directory of Open Access Journals (Sweden)

    Sungil Jeon

    2016-12-01

    Full Text Available We aimed to investigate the relationship between membrane material and the development of membrane fouling in a membrane bioreactor (MBR using membranes with different pore sizes and hydrophilicities. Batch filtration tests were performed using submerged single hollow fiber membrane ultrafiltration (UF modules with different polymeric membrane materials including cellulose acetate (CA, polyethersulfone (PES, and polyvinylidene fluoride (PVDF with activated sludge taken from a municipal wastewater treatment plant. The three UF hollow fiber membranes were prepared by a non-solvent-induced phase separation method and had similar water permeabilities and pore sizes. The results revealed that transmembrane pressure (TMP increased more sharply for the hydrophobic PVDF membrane than for the hydrophilic CA membrane in batch filtration tests, even when membranes with similar permeabilities and pore sizes were used. PVDF hollow fiber membranes with smaller pores had greater fouling propensity than those with larger pores. In contrast, CA hollow fiber membranes showed good mitigation of membrane fouling regardless of pore size. The results obtained in this study suggest that the surface hydrophilicity and pore size of UF membranes clearly affect the fouling properties in MBR operation when using activated sludge.

  14. High flux and antifouling properties of negatively charged membrane for dyeing wastewater treatment by membrane distillation.

    Science.gov (United States)

    An, Alicia Kyoungjin; Guo, Jiaxin; Jeong, Sanghyun; Lee, Eui-Jong; Tabatabai, S Assiyeh Alizadeh; Leiknes, TorOve

    2016-10-15

    This study investigated the applicability of membrane distillation (MD) to treat dyeing wastewater discharged by the textile industry. Four different dyes containing methylene blue (MB), crystal violet (CV), acid red 18 (AR18), and acid yellow 36 (AY36) were tested. Two types of hydrophobic membranes made of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) were used. The membranes were characterized by testing against each dye (foulant-foulant) and the membrane-dye (membrane-foulant) interfacial interactions and their mechanisms were identified. The MD membranes possessed negative charges, which facilitated the treatment of acid and azo dyes of the same charge and showed higher fluxes. In addition, PTFE membrane reduced the wettability with higher hydrophobicity of the membrane surface. The PTFE membrane evidenced especially its resistant to dye absorption, as its strong negative charge and chemical structure caused a flake-like (loose) dye-dye structure to form on the membrane surface rather than in the membrane pores. This also enabled the recovery of flux and membrane properties by water flushing (WF), thereby direct-contact MD with PTFE membrane treating 100 mg/L of dye mixtures showed stable flux and superior color removal during five days operation. Thus, MD shows a potential for stable long-term operation in conjunction with a simple membrane cleaning process, and its suitability in dyeing wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Effects of fractal roughness of membrane surfaces on interfacial interactions associated with membrane fouling in a membrane bioreactor.

    Science.gov (United States)

    Feng, Shushu; Yu, Genying; Cai, Xiang; Eulade, Mahoro; Lin, Hongjun; Chen, Jianrong; Liu, Yong; Liao, Bao-Qiang

    2017-11-01

    Fractal roughness is one of the most important properties of a fractal surface. In this study, it was found that, randomly rough membrane surface was a fractal surface, which could be digitally modeled by a modified two-variable Weierstrass-Mandelbrot (WM) function. Fractal roughness of membrane surfaces has a typical power function relation with the statistical roughness of the modeled surface. Assessment of interfacial interactions showed that an increase in fractal roughness of membrane surfaces will strengthen and prolong the interfacial interactions between membranes and foulants, and under conditions in this study, will significantly increase the adhesion propensity of a foulant particle on membrane surface. This interesting result can be attributed to that increase in fractal roughness simultaneously improves separation distance and interaction surface area for adhesion of a foulant particle. This study gives deep insights into interfacial interactions and membrane fouling in MBRs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Charge Inversion in semi-permeable membranes

    Science.gov (United States)

    Das, Siddhartha; Sinha, Shayandev; Jing, Haoyuan

    Role of semi-permeable membranes like lipid bilayer is ubiquitous in a myriad of physiological and pathological phenomena. Typically, lipid membranes are impermeable to ions and solutes; however, protein channels embedded in the membrane allow the passage of selective, small ions across the membrane enabling the membrane to adopt a semi-permeable nature. This semi-permeability, in turn, leads to electrostatic potential jump across the membrane, leading to effects such as regulation of intracellular calcium, extracellular-vesicle-membrane interactions, etc. In this study, we theoretically demonstrate that this semi-permeable nature may trigger the most remarkable charge inversion (CI) phenomenon in the cytosol-side of the negatively-charged lipid bilayer membrane that are selectively permeable to only positive ions of a given salt. This CI is manifested as the changing of the sign of the electrostatic potential from negative to positive from the membrane-cytosol interface to deep within the cytosol. We study the impact of the parameters such as the concentration of this salt with selectively permeable ions as well as the concentration of an external salt in the development of this CI phenomenon. We anticipate such CI will profoundly influence the interaction of membrane and intra-cellular moieties (e.g., exosome or multi-cellular vesicles) having implications for a host of biophysical processes.

  17. Poly-thiosemicarbazide membrane for gold recovery

    KAUST Repository

    Villalobos, Luis Francisco

    2014-11-01

    A novel polymeric membrane adsorber with a high density of adsorption sites that can selectively capture Au(III) ions, is proposed as an efficient alternative to recover gold from dilute solutions. Poly-thiosemicarbazide (PTSC), a polymer that contains one chelate site per monomeric unit, was used to fabricate the membranes. This polymer can be easily processed into membranes by a phase inversion technique, resulting in an open and interconnected porous structure suitable for high flux liquid phase applications. This method overcomes the usual low capacities of membrane adsorbents by selecting a starting material that contains the adsorption sites within it, therefore avoiding the necessity to add an external agent into the membrane matrix. The resulting mechanically stable PTSC membranes can operate in a pressure driven permeation process, which eliminates the diffusion limitations commonly present in packed column adsorption processes. This process can selectively recover 97% of the gold present in a solution containing a 9-fold higher copper concentration, while operating at a flux as high as 1868 L/m2 h. The maximum gold uptake measured without sacrificing the mechanical stability of the membrane was 5.4 mmol Au/g. Furthermore the gold can be easily eluted from the membrane with a 0.1 M thiourea solution and the membrane can be reused for at least three cycles without any decrease in its performance. Finally, the ability of this membrane for recovering metals from real-life samples, like seawater and tap water, was tested with promising results.

  18. Modeling branching pore structures in membrane filters

    Science.gov (United States)

    Sanaei, Pejman; Cummings, Linda J.

    2016-11-01

    Membrane filters are in widespread industrial use, and mathematical models to predict their efficacy are potentially very useful, as such models can suggest design modifications to improve filter performance and lifetime. Many models have been proposed to describe particle capture by membrane filters and the associated fluid dynamics, but most such models are based on a very simple structure in which the pores of the membrane are assumed to be simple circularly-cylindrical tubes spanning the depth of the membrane. Real membranes used in applications usually have much more complex geometry, with interconnected pores which may branch and bifurcate. Pores are also typically larger on the upstream side of the membrane than on the downstream side. We present an idealized mathematical model, in which a membrane consists of a series of bifurcating pores, which decrease in size as the membrane is traversed. Feed solution is forced through the membrane by applied pressure, and particles are removed from the feed either by sieving, or by particle adsorption within pores (which shrinks them). Thus the membrane's permeability decreases as the filtration progresses, ultimately falling to zero. We discuss how filtration efficiency depends on the characteristics of the branching structure. Partial support from NSF DMS 1261596 is gratefully acknowledged.

  19. Metal ion separations using reactive membranes

    International Nuclear Information System (INIS)

    Way, J.D.

    1993-01-01

    A membrane is a barrier between two phases. If one component of a mixture moves through the membrane faster than another mixture component, a separation can be accomplished. Membranes are used commercially for many applications including gas separations, water purification, particle filtration, and macromolecule separations (Abelson). There are two points to note concerning this definition. First, a membrane is defined based on its function, not the material used to make the membrane. Secondly, a membrane separation is a rate process. The separation is accomplished by a driving force, not by equilibrium between phases. Liquids that are immiscible with the feed and product streams can also be used as membrane materials. Different solutes will have different solubilities and diffusion coefficients in a liquid. The product of the diffusivity and the solubility is known as the permeability coefficient, which is proportional to the solute flux. Differences in permeability coefficient will produce a separation between solutes at constant driving force. Because the diffusion coefficients in liquids are typically orders of magnitude higher than in polymers, a larger flux can be obtained. Further enhancements can be accomplished by adding a nonvolatile complexation agent to the liquid membrane. One can then have either coupled or facilitated transport of metal ions through a liquid membrane. The author describes two implementations of this concept, one involving a liquid membrane supported on a microporous membrane, and the other an emulsion liquid membrane, where separation occurs to internal receiving phases. Applications and costing studies for this technology are reviewed, and a brief summary of some of the problems with liquid membranes is presented

  20. Membrane topology of hedgehog acyltransferase.

    Science.gov (United States)

    Matevossian, Armine; Resh, Marilyn D

    2015-01-23

    Hedgehog acyltransferase (Hhat) is a multipass transmembrane enzyme that mediates the covalent attachment of the 16-carbon fatty acid palmitate to the N-terminal cysteine of Sonic Hedgehog (Shh). Palmitoylation of Shh by Hhat is critical for short and long range signaling. Knowledge of the topological organization of Hhat transmembrane helices would enhance our understanding of Hhat-mediated Shh palmitoylation. Bioinformatics analysis of transmembrane domains within human Hhat using 10 different algorithms resulted in highly consistent predictions in the C-terminal, but not in the N-terminal, region of Hhat. To empirically determine the topology of Hhat, we designed and exploited Hhat constructs containing either terminal or 12 different internal epitope tags. We used selective permeabilization coupled with immunofluorescence as well as a protease protection assay to demonstrate that Hhat contains 10 transmembrane domains and 2 re-entrant loops. The invariant His and highly conserved Asp residues within the membrane-bound O-acyltransferase (MBOAT) homology domain are segregated on opposite sides of the endoplasmic reticulum membrane. The localization of His-379 on the lumenal membrane surface is consistent with a role for this invariant residue in catalysis. Analysis of the activity and stability of the Hhat constructs revealed that the C-terminal MBOAT domain is especially sensitive to manipulation. Moreover, there was remarkable similarity in the overall topological organization of Hhat and ghrelin O-acyltransferase, another MBOAT family member. Knowledge of the topological organization of Hhat could serve as an important tool for further design of selective Hhat inhibitors. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Aneurysm of the membranous septum

    International Nuclear Information System (INIS)

    Goebel, N.; Haller, D.; Hinterauer, L.; Jenni, R.; Zurich Univ.

    1984-01-01

    Amongst 9000 patients on whom angiocardiograms has been carried out, a membranous septum aneurysm (MSA) was found in 47. In nine patients out of 27 the MSA could be demonstrated by sonography. The most common abnormalities accompanying this lesion were disturbances in rhythm and conduction (in 29 patients), ventricular septal defect in 29 and aortic insufficiency in 14. Complications included bacterial endocarditis in five patients (three with aortic insufficiency and two with sepsis lenta), aortic insufficiency (which was not of rheumatic or bacterial origin in three patients with conduction defects) and thirteen patients with abnormalities of cardiac rhythm with small VSDs. (orig.) [de

  2. Aneurysm of the membranous septum

    Energy Technology Data Exchange (ETDEWEB)

    Goebel, N.; Haller, D.; Hinterauer, L.; Jenni, R.

    1984-02-01

    Amongst 9000 patients on whom angiocardiograms has been carried out, a membranous septum aneurysm (MSA) was found in 47. In nine patients out of 27 the MSA could be demonstrated by sonography. The most common abnormalities accompanying this lesion were disturbances in rhythm and conduction (in 29 patients), ventricular septal defect in 29 and aortic insufficiency in 14. Complications included bacterial endocarditis in five patients (three with aortic insufficiency and two with sepsis lenta), aortic insufficiency (which was not of rheumatic or bacterial origin in three patients with conduction defects) and thirteen patients with abnormalities of cardiac rhythm with small VSDs.

  3. Chitosan-based ferrimagnetic membrane

    International Nuclear Information System (INIS)

    Macedo, M.A.; Silva, M.N.B.; Cestari, A.R.; Vieira, E.F.S.; Sasaki, J.M.; Goes, J.C.; Aguiar, J. Albino

    2004-01-01

    A chitosan-based ferrimagnetic membrane (Chitosan/NiFe 2 O 4 ) was prepared and it showed a typical magnetization of soft ferrimagnetic material with M s =16 emu/g at 50 kOe and a high capacity to extract Hg(II), Cu(II) and Zn(II) ions from aqueous solutions. These results indicate that the Chitosan/NiFe 2 O 4 is a good candidate to remove heavy metals from polluted water with the possibility that its recovery can be done by an electromagnet

  4. Hollow fiber liquid supported membranes

    International Nuclear Information System (INIS)

    Violante, V.

    1987-01-01

    The hollow fiber system are well known and developed in the scientific literature because of their applicability in the process separation units. The authors approach to a mathematical model for a particular hollow fiber system, usin liquid membranes. The model has been developed in order to obtain a suitable tool for a sensitivy analysis and for a scaling-up. This kind of investigation is very usefull from an engineering point of view, to get a spread range of information to build up a pilot plant from the laboratory scale

  5. SOFC and Gas Separation Membranes

    DEFF Research Database (Denmark)

    Hagen, Anke; Hendriksen, Peter Vang; Søgaard, Martin

    2009-01-01

    from air. Subsequent separation and sequestration of CO2 is therefore easier on a SOFC plant than on conventional power plants based on combustion. Oxide ion conducting materials may be used for gas separation purposes with close to 100 % selectivity. They typically work in the same temperature range...... as SOFCs. Such membranes can potentially be used in Oxyfuel processes as well as in IGCC (Integrated Gasification Combined Cycle) power plants for supply of process oxygen, which may reduce cost of carbon capture and storage as dilution of the flue gas with nitrogen is avoided. Both technologies are very...

  6. Advanced membrane electrode assemblies for fuel cells

    Science.gov (United States)

    Kim, Yu Seung; Pivovar, Bryan S.

    2012-07-24

    A method of preparing advanced membrane electrode assemblies (MEA) for use in fuel cells. A base polymer is selected for a base membrane. An electrode composition is selected to optimize properties exhibited by the membrane electrode assembly based on the selection of the base polymer. A property-tuning coating layer composition is selected based on compatibility with the base polymer and the electrode composition. A solvent is selected based on the interaction of the solvent with the base polymer and the property-tuning coating layer composition. The MEA is assembled by preparing the base membrane and then applying the property-tuning coating layer to form a composite membrane. Finally, a catalyst is applied to the composite membrane.

  7. Biophysical studies of membrane channel polypeptides

    CERN Document Server

    Galbraith, T P

    2001-01-01

    Membrane channels facilitate the flow of ions across biological membranes, a process which is important in numerous cellular functions. The study of large integral membrane proteins is made difficult by identification, production and purification problems, and detailed knowledge of their three-dimensional structures is relatively scarce. The study of simple 'model' membrane proteins has given valuable insight into the structures and dynamics of membrane proteins in general. The bacterial peptide gramicidin has been the subject of intense study for many years, and has provided important information into the structural basis of channel function. Peptaibols, a class of fungal membrane peptides which includes alamethicin and antiamoebin, have also been useful in relating structural details to molecular ion transport processes. Gramicidin crystals were grown in the presence of phospholipids with various headgroups and acyl chains. The diffraction patterns of the crystals obtained were processed, but found to be in...

  8. The plant plasma membrane H+-ATPase

    DEFF Research Database (Denmark)

    Ekberg, Kira

      The very high mobility of protons in aqueous solutions demands special features of membrane proton transporters to sustain efficient yet regulated proton transport across biological membranes. By the use of the chemical energy of ATP, plasma-membrane-embedded H+-ATPases extrude protons from cells...... of plants and fungi to generate electrochemical proton gradients. A recently published crystal structure of a plasma membrane H(+)-ATPase contributes to our knowledge about the mechanism of these essential enzymes. Together with biochemical and structural data presented in this thesis we are now able...... to describe the basic molecular components that allow the plasma membrane proton H+-ATPase to carry out proton transport against large membrane potentials. Moreover, a completely new paradigm for post-translational activation of these proteins is presented. The talk will focus on the following themes...

  9. Porous polyoxadiazole membranes for harsh environment

    KAUST Repository

    Maab, Husnul

    2013-10-01

    A series of polyoxadiazoles with exceptionally high stability at temperatures as high as 370°C and in oxidative medium has been synthesized by polycondensation and manufactured into porous membranes by phase inversion. The membranes were characterized by thermal analysis (TGA), chemical stability was measured by immersion test, oxidative stability by Fenton\\'s test, pore diameter by porosimetry and the morphology by FESEM. The polymers are soluble only in sulfuric acid and are stable in organic solvents like NMP, THF and isopropanol. The membranes selectivity was confirmed by separation of polystyrene standards with different molecular weights. Most membranes were characterized as having a cut-off of 60,000. g/mol. Being stable under harsh environments, the membranes have incomparable characteristics with perspectives of application in chemical and pharmaceutical industry, catalytic reactors, in combination with oxidative processes and other applications so far envisioned only for ceramic membranes. © 2013.

  10. Lignin-based membranes for electrolyte transference

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao; Garcia-Valls, Ricard [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona (Spain); Benavente, Juana [Department of Applied Fisics, Faculty of Science, University of Malaga, Malaga (Spain)

    2005-08-18

    Homogeneous PSf-LS membranes are formed by incorporating Lignosulfonate (LS) into the Polysulfone (PSf) network. LS obtained from sulfite pulping process contains sulfonic acid groups that will act as proton transport media. PSf-LS membranes were characterized by reflectance Infrared and scanning electron microscopy. LS showed significant influence on membrane morphology. Higher LS concentration caused a decrease in macrovoid formation and induced larger pores. Precipitation temperature was investigated as influencing parameter. Proton fluxes through PSf-LS membranes were measured by transport experiments. Impedance analysis confirmed that PSf-LS membranes possess ion conductivity. The selected PSf-LS membranes exhibited high selectivity for proton over methanol, which indicates their potential applicability in direct methanol fuel cell (DMFC). (author)

  11. Inflation and Instability of a Polymeric Membrane

    DEFF Research Database (Denmark)

    Hassager, Ole; Kristensen, Susanne Brogaard; Larsen, Johannes Ruben

    1999-01-01

    We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane. The polymeric material is described by an arbitrary combination of a viscoelastic and a purely viscous component to the stress. Some viscoelastic materials described by a Mooney......-Rivlin model show a monotone increasing pressure during inflation of a spherical membrane. These materials develop a homogeneous membrane thickness in agreement with the Considere-Pearson condition. Molecularly based models such as the neo-Hookean, Doi-Edwards or Tom-Pom model show a pressure maximum when...... inflated. Membranes described by these models develop a local thinning of the membrane which may lead to bursting in finite time. (C) 1999 Elsevier Science B.V. All rights reserved....

  12. Membrane engineering in biotechnology: quo vamus?

    Science.gov (United States)

    Rios, Gilbert M; Belleville, Marie-Pierre; Paolucci-Jeanjean, Delphine

    2007-06-01

    Membranes are essential to a range of applications, including the production of potable water, energy generation, tissue repair, pharmaceutical production, food packaging, and the separations needed for the manufacture of chemicals, electronics and a range of other products. Therefore, they are considered to be "dominant technologies" by governments and industry in several prominent countries--for example, USA, Japan and China. When combined with catalysts, membranes are at the basis of life, and membrane-based biomimetism is a key tool to obtain better quality products and environmentally friendly developments for our societies. Biology has a main part in this global landscape because it simultaneously provides the "model" (with natural biological membranes) and represents a considerable field of applications for new artificial membranes (biotreatments, bioconversions and artificial organs). In this article, our objective is to open up this enthralling area and to give our views about the future of membranes in biotechnology.

  13. Isomeric Detergent Comparison for Membrane Protein Stability

    DEFF Research Database (Denmark)

    Cho, Kyung Ho; Hariharan, Parameswaran; Mortensen, Jonas S.

    2016-01-01

    Membrane proteins encapsulated by detergent micelles are widely used for structural study. Because of their amphipathic property, detergents have the ability to maintain protein solubility and stability in an aqueous medium. However, conventional detergents have serious limitations in their scope...... and utility, particularly for eukaryotic membrane proteins and membrane protein complexes. Thus, a number of new agents have been devised; some have made significant contributions to membrane protein structural studies. However, few detergent design principles are available. In this study, we prepared meta....../stability of the membrane proteins. We propose that interplay between the hydrophile–lipophile balance (HLB) and alkyl chain length is of central importance for high detergent efficacy. In addition, differences in inter-alkyl-chain distance between the isomers influence the ability of the detergents to stabilise membrane...

  14. Functionalization of a Hydrophilic Commercial Membrane Using Inorganic-Organic Polymers Coatings for Membrane Distillation

    Directory of Open Access Journals (Sweden)

    Lies Eykens

    2017-06-01

    Full Text Available Membrane distillation is a thermal separation technique using a microporous hydrophobic membrane. One of the concerns with respect to the industrialization of the technique is the development of novel membranes. In this paper, a commercially available hydrophilic polyethersulfone membrane with a suitable structure for membrane distillation was modified using available hydrophobic coatings using ORMOCER® technology to obtain a hydrophobic membrane that can be applied in membrane distillation. The surface modification was performed using a selection of different components, concentrations, and application methods. The resulting membranes can have two hydrophobic surfaces or a hydrophobic and hydrophilic surface depending on the application method. An extensive characterization procedure confirmed the suitability of the coating technique and the obtained membranes for membrane distillation. The surface contact angle of water could be increased from 27° up to 110°, and fluxes comparable to membranes commonly used for membrane distillation were achieved under similar process conditions. A 100 h test demonstrated the stability of the coating and the importance of using sufficiently stable base membranes.

  15. High flux and antifouling properties of negatively charged membrane for dyeing wastewater treatment by membrane distillation

    KAUST Repository

    An, Alicia Kyoungjin

    2016-07-25

    This study investigated the applicability of membrane distillation (MD) to treat dyeing wastewater discharged by the textile industry. Four different dyes containing methylene blue (MB), crystal violet (CV), acid red 18 (AR), and acid yellow 36 (AY) were tested. Two types of hydrophobic membranes made of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) were used. The membranes were characterized by testing against each dye (foulant-foulant) and the membrane–dye (membrane-foulant) interfacial interactions and their mechanisms were identified. The MD membranes possessed negative charges, which facilitated the treatment of acid and azo dyes of the same charge and showed higher fluxes. In addition, PTFE membrane reduced the wettability with higher hydrophobicity of the membrane surface. The PTFE membrane evidenced especially its resistant to dye absorption, as its strong negative charge and chemical structure caused a flake-like (loose) dye–dye structure to form on the membrane surface rather than in the membrane pores. This also enabled the recovery of flux and membrane properties by water flushing (WF), thereby direct-contact MD with PTFE membrane treating 100 mg/L of dye mixtures showed stable flux and superior color removal during five days operation. Thus, MD shows a potential for stable long-term operation in conjunction with a simple membrane cleaning process, and its suitability in dyeing wastewater treatment.

  16. Characterising antimicrobial protein-membrane complexes

    International Nuclear Information System (INIS)

    Xun, Gloria; Dingley, Andrew; Tremouilhac, Pierre

    2009-01-01

    Full text: Antimicrobial proteins (AMPs) are host defence molecules that protect organisms from microbial infection. A number of hypotheses for AMP activity have been proposed which involve protein membrane interactions. However, there is a paucity of information describing AMP-membrane complexes in detail. The aim of this project is to characterise the interactions of amoebapore-A (APA-1) with membrane models using primarily solution-state NMR spectroscopy. APA-1 is an AMP which is regulated by a pH-dependent dimerisation event. Based on the atomic resolution solution structure of monomeric APA-1, it is proposed that this dimerisation is a prerequisite for ring-like hexameric pore formation. Due to the cytotoxicity of APA-1, we have developed a cell-free system to produce this protein. To facilitate our studies, we have adapted the cell-free system to isotope label APA-1. 13 C /15 N -enriched APA-1 sample was achieved and we have begun characterising APA-1 dimerisation and membrane interactions using NMR spectroscopy and other biochemical/biophysical methods. Neutron reflectometry is a surface-sensitive technique and therefore represents an ideal technique to probe how APA-1 interacts with membranes at the molecular level under different physiological conditions. Using Platypus, the pH-induced APA-1-membrane interactions should be detectable as an increase of the amount of protein adsorbed at the membrane surface and changes in the membrane properties. Specifically, detailed information of the structure and dimensions of the protein-membrane complex, the position and amount of the protein in the membrane, and the perturbation of the membrane phospholipids on protein incorporation can be extracted from the neutron reflectometry measurement. Such information will enable critical assessment of current proposed mechanisms of AMP activity in bacterial membranes and complement our NMR studies

  17. Anisotropic Membrane Curvature Sensing by Amphipathic Peptides

    OpenAIRE

    Gómez-Llobregat, Jordi; Elías-Wolff, Federico; Lindén, Martin

    2016-01-01

    Many proteins and peptides have an intrinsic capacity to sense and induce membrane curvature, and play crucial roles for organizing and remodelling cell membranes. However, the molecular driving forces behind these processes are not well understood. Here, we describe a new approach to study curvature sensing, by simulating the direction-dependent interactions of single molecules with a buckled lipid bilayer. We analyse three amphipathic antimicrobial peptides, a class of membrane-associated m...

  18. Recent Membrane Development for Pervaporation Processes

    KAUST Repository

    Ong, Yee Kang

    2016-03-11

    Pervaporation has been regarded as a promising separation technology in separating azeotropic mixtures, solutions with similar boiling points, thermally sensitive compounds, organic–organic mixtures as well as in removing dilute organics from aqueous solutions. As the pervaporation membrane is one of the crucial factors in determining the overall efficiency of the separation process, this article reviews the research and development (R&D) of polymeric pervaporation membranes from the perspective of membrane fabrication procedures and materials.

  19. Examining hemodialyzer membrane performance using proteomic technologies.

    Science.gov (United States)

    Bonomini, Mario; Pieroni, Luisa; Di Liberato, Lorenzo; Sirolli, Vittorio; Urbani, Andrea

    2018-01-01

    The success and the quality of hemodialysis therapy are mainly related to both clearance and biocompatibility properties of the artificial membrane packed in the hemodialyzer. Performance of a membrane is strongly influenced by its interaction with the plasma protein repertoire during the extracorporeal procedure. Recognition that a number of medium-high molecular weight solutes, including proteins and protein-bound molecules, are potentially toxic has prompted the development of more permeable membranes. Such membrane engineering, however, may cause loss of vital proteins, with membrane removal being nonspecific. In addition, plasma proteins can be adsorbed onto the membrane surface upon blood contact during dialysis. Adsorption can contribute to the removal of toxic compounds and governs the biocompatibility of a membrane, since surface-adsorbed proteins may trigger a variety of biologic blood pathways with pathophysiologic consequences. Over the last years, use of proteomic approaches has allowed polypeptide spectrum involved in the process of hemodialysis, a key issue previously hampered by lack of suitable technology, to be assessed in an unbiased manner and in its full complexity. Proteomics has been successfully applied to identify and quantify proteins in complex mixtures such as dialysis outflow fluid and fluid desorbed from dialysis membrane containing adsorbed proteins. The identified proteins can also be characterized by their involvement in metabolic and signaling pathways, molecular networks, and biologic processes through application of bioinformatics tools. Proteomics may thus provide an actual functional definition as to the effect of a membrane material on plasma proteins during hemodialysis. Here, we review the results of proteomic studies on the performance of hemodialysis membranes, as evaluated in terms of solute removal efficiency and blood-membrane interactions. The evidence collected indicates that the information provided by proteomic

  20. Biogenesis and Membrane Targeting of Lipoproteins.

    Science.gov (United States)

    Narita, Shin-Ichiro; Tokuda, Hajime

    2010-09-01

    Bacterial lipoproteins represent a unique class of membrane proteins, which are anchored to membranes through triacyl chains attached to the amino-terminal cysteine. They are involved in various functions localized in cell envelope. Escherichia coli possesses more than 90 species of lipoproteins, most of which are localized in the outer membrane, with others being in the inner membrane. All lipoproteins are synthesized in the cytoplasm with an N-terminal signal peptide, translocated across the inner membrane by the Sec translocon to the periplasmic surface of the inner membrane, and converted to mature lipoproteins through sequential reactions catalyzed by three lipoprotein-processing enzymes: Lgt, LspA, and Lnt. The sorting of lipoproteins to the outer membrane requires a system comprising five Lol proteins. An ATP-binding cassette transporter, LolCDE, initiates the sorting by mediating the detachment of lipoproteins from the inner membrane. Formation of the LolA-lipoprotein complex is coupled to this LolCDE-dependent release reaction. LolA accommodates the amino-terminal acyl chain of lipoproteins in its hydrophobic cavity, thereby generating a hydrophilic complex that can traverse the periplasmic space by diffusion. Lipoproteins are then transferred to LolB on the outer membrane and anchored to the inner leaflet of the outer membrane by the action of LolB. In contrast, since LolCDE does not recognize lipoproteins possessing Asp at position +2, these lipoproteins remain anchored to the inner membrane. Genes for Lol proteins are widely conserved among gram-negative bacteria, and Lol-mediated outer membrane targeting of lipoproteins is considered to be the general lipoprotein localization mechanism.

  1. Outer membrane proteins of pathogenic spirochetes

    OpenAIRE

    Cullen, Paul A.; Haake, David A.; Adler, Ben

    2004-01-01

    Pathogenic spirochetes are the causative agents of several important diseases including syphilis, Lyme disease, leptospirosis, swine dysentery, periodontal disease and some forms of relapsing fever. Spirochetal bacteria possess two membranes and the proteins present in the outer membrane are at the site of interaction with host tissue and the immune system. This review describes the current knowledge in the field of spirochetal outer membrane protein (OMP) biology. What is known concerning bi...

  2. Biomimetic Membrane Arrays on Cast Hydrogel Supports

    DEFF Research Database (Denmark)

    Roerdink-Lander, Monique; Ibragimova, Sania; Rein Hansen, Christian

    2011-01-01

    Lipid bilayers are intrinsically fragile and require mechanical support in technical applications based on biomimetic membranes. Tethering the lipid bilayer membranes to solid substrates, either directly through covalent or ionic substrate−lipid links or indirectly on substrate-supported cushions......, provides mechanical support but at the cost of small molecule transport through the membrane−support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane−support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE...

  3. Progress in surface and membrane science

    CERN Document Server

    Cadenhead, D A; Rosenberg, M D

    1975-01-01

    Progress in Surface and Membrane Science, Volume 9 covers the developments in surface and membrane science. The book discusses the physical adsorption of gases and vapors in micropores; the chemisorption theory; and the role of radioisotopes in the studies of chemisorption and catalysis. The text also describes the interaction of ions with monolayers; and the isolation and characterization of mycoplasma membranes. Chemists, physical chemists, and microbiologists will find the book useful.

  4. Integral Membrane Proteins and Bilayer Proteomics

    OpenAIRE

    Whitelegge, Julian P.

    2013-01-01

    Integral membrane proteins reside within the bilayer membranes that surround cells and organelles, playing critical roles in movement of molecules across them and the transduction of energy and signals. While their extreme amphipathicity presents technical challenges, biological mass spectrometry has been applied to all aspects of membrane protein chemistry and biology, including analysis of primary, secondary, tertiary and quaternary structure, as well as the dynamics that accompany function...

  5. Integral membrane proteins and bilayer proteomics.

    Science.gov (United States)

    Whitelegge, Julian P

    2013-03-05

    Integral membrane proteins reside within the bilayer membranes that surround cells and organelles, playing critical roles in movement of molecules across them and the transduction of energy and signals. While their extreme amphipathicity presents technical challenges, biological mass spectrometry has been applied to all aspects of membrane protein chemistry and biology, including analysis of primary, secondary, tertiary, and quaternary structures as well as the dynamics that accompany functional cycles and catalysis.

  6. Linking molecular motors to membrane cargo

    OpenAIRE

    Akhmanova, Anna; Hammer, John A.

    2010-01-01

    Three types of motors, myosins, kinesins and cytoplasmic dynein, cooperate to transport intracellular membrane organelles. Transport of each cargo is determined by recruitment of specific sets of motors and their regulation. Targeting of motors to membranes often depends on the formation of large multiprotein assemblies and can be influenced by membrane lipid composition. Motor activity can be regulated by cargo-induced conformational changes such as unfolding or dimerization. The architectur...

  7. Membrane Cholesterol Modulates Superwarfarin Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Marangoni, M. Natalia; Martynowycz, Michael W.; Kuzmenko, Ivan; Braun, David; Polak, Paul E.; Weinberg, Guy; Rubinstein, Israel; Gidalevitz, David; Feinstein, Douglas L.

    2016-04-26

    Superwarfarins are modified analogs of warfarin with additional lipophilic aromatic rings, up to 100-fold greater potency, and longer biological half-lives. We hypothesized that increased hydrophobicity allowed interactions with amphiphilic membranes and modulation of biological responses. We find that superwarfarins brodifacoum and difenacoum increase lactate production and cell death in neuroblastoma cells. In contrast, neither causes changes in glioma cells that have higher cholesterol content. After choleterol depletion, lactate production was increased and cell viability was reduced. Drug-membrane interactions were examined by surface X-ray scattering using Langmuir monolayers of dipalmitoylphosphatidylcholine and/or cholesterol. Specular X-ray reflectivity data revealed that superwarfarins, but not warfarin, intercalate between dipalmitoylphosphatidylcholine molecules, whereas grazing incidence X-ray diffraction demonstrated changes in lateral crystalline order of the film. Neither agent showed significant interactions with monolayers containing >20% cholesterol. These findings demonstrate an affinity of superwarfarins to biomembranes and suggest that cellular responses to these agents are regulated by cholesterol content.

  8. Molecular machines open cell membranes.

    Science.gov (United States)

    García-López, Víctor; Chen, Fang; Nilewski, Lizanne G; Duret, Guillaume; Aliyan, Amir; Kolomeisky, Anatoly B; Robinson, Jacob T; Wang, Gufeng; Pal, Robert; Tour, James M

    2017-08-30

    Beyond the more common chemical delivery strategies, several physical techniques are used to open the lipid bilayers of cellular membranes. These include using electric and magnetic fields, temperature, ultrasound or light to introduce compounds into cells, to release molecular species from cells or to selectively induce programmed cell death (apoptosis) or uncontrolled cell death (necrosis). More recently, molecular motors and switches that can change their conformation in a controlled manner in response to external stimuli have been used to produce mechanical actions on tissue for biomedical applications. Here we show that molecular machines can drill through cellular bilayers using their molecular-scale actuation, specifically nanomechanical action. Upon physical adsorption of the molecular motors onto lipid bilayers and subsequent activation of the motors using ultraviolet light, holes are drilled in the cell membranes. We designed molecular motors and complementary experimental protocols that use nanomechanical action to induce the diffusion of chemical species out of synthetic vesicles, to enhance the diffusion of traceable molecular machines into and within live cells, to induce necrosis and to introduce chemical species into live cells. We also show that, by using molecular machines that bear short peptide addends, nanomechanical action can selectively target specific cell-surface recognition sites. Beyond the in vitro applications demonstrated here, we expect that molecular machines could also be used in vivo, especially as their design progresses to allow two-photon, near-infrared and radio-frequency activation.

  9. Biomolecular Transport through Hemofiltration Membranes

    Science.gov (United States)

    Datta, Subhra; Fissell, William H.; Roy, Shuvo

    2009-01-01

    A theoretical model for filtration of large solutes through a pore in the presence of transmembrane pressures, applied/induced electric fields, and dissimilar interactions at the pore entrance and exit is developed to characterize and predict the experimental performance of a hemofiltration membrane with nanometer scale pores designed for a proposed implantable Renal Assist Device (RAD). The model reveals that the sieving characteristics of the membrane can be improved by applying an external electric field, and ensuring a smaller ratio of the pore-feed and pore-permeate equilibrium partitioning coefficients when diffusion is present. The model is then customized to study the sieving characteristics for both charged and uncharged solutes in the slit-shaped nanopores of the hemofiltration device for the RAD. The effect of streaming potential or induced fields are found to be negligible under representative operating conditions. Experimental data on the sieving coefficient of bovine serum albumin, carbonic anhydrase and thyroglobulin are reported and compared with the theoretical predictions. Both steric and electrostatic partitioning are considered and the comparison suggests that in general electrostatic effects are present in the filtration of proteins though some data, particularly those recorded in a strongly hypertonic solution (10×PBS), show better agreement with the steric partitioning theory. PMID:19184436

  10. Molecular machines open cell membranes

    Science.gov (United States)

    García-López, Víctor; Chen, Fang; Nilewski, Lizanne G.; Duret, Guillaume; Aliyan, Amir; Kolomeisky, Anatoly B.; Robinson, Jacob T.; Wang, Gufeng; Pal, Robert; Tour, James M.

    2017-08-01

    Beyond the more common chemical delivery strategies, several physical techniques are used to open the lipid bilayers of cellular membranes. These include using electric and magnetic fields, temperature, ultrasound or light to introduce compounds into cells, to release molecular species from cells or to selectively induce programmed cell death (apoptosis) or uncontrolled cell death (necrosis). More recently, molecular motors and switches that can change their conformation in a controlled manner in response to external stimuli have been used to produce mechanical actions on tissue for biomedical applications. Here we show that molecular machines can drill through cellular bilayers using their molecular-scale actuation, specifically nanomechanical action. Upon physical adsorption of the molecular motors onto lipid bilayers and subsequent activation of the motors using ultraviolet light, holes are drilled in the cell membranes. We designed molecular motors and complementary experimental protocols that use nanomechanical action to induce the diffusion of chemical species out of synthetic vesicles, to enhance the diffusion of traceable molecular machines into and within live cells, to induce necrosis and to introduce chemical species into live cells. We also show that, by using molecular machines that bear short peptide addends, nanomechanical action can selectively target specific cell-surface recognition sites. Beyond the in vitro applications demonstrated here, we expect that molecular machines could also be used in vivo, especially as their design progresses to allow two-photon, near-infrared and radio-frequency activation.

  11. MEMBRANE BIOREACTOR FOR TREATMENT OF RECALCITRANT WASTEWATERS

    Directory of Open Access Journals (Sweden)

    Suprihatin Suprihatin

    2012-02-01

    Full Text Available The low biodegradable wastewaters remain a challenge in wastewater treatment technology. The performance of membrane bioreactor systems with submerged hollow fiber micro- and ultrafiltration membrane modules were examined for purifying recalcitrant wastewaters of leachate of a municipal solid waste open dumping site and effluent of pulp and paper mill. The use of MF and UF membrane bioreactor systems showed an efficient treatment for both types wastewaters with COD reduction of 80-90%. The membrane process achieved the desirable effects of maintaining reasonably high biomass concentration and long sludge retention time, while producing a colloid or particle free effluent. For pulp and paper mill effluent a specific sludge production of 0.11 kg MLSS/kg COD removed was achieved. A permeate flux of about 5 L/m²h could be achieved with the submerged microfiltration membrane. Experiments using ultrafiltration membrane produced relatively low permeate fluxes of 2 L/m²h. By applying periodical backwash, the flux could be improved significantly. It was indicated that the particle or colloid deposition on membrane surface was suppressed by backwash, but reformation of deposit was not effectively be prevented by shear-rate effect of aeration. Particle and colloid started to accumulate soon after backwash. Construction of membrane module and operation mode played a critical role in achieving the effectiveness of aeration in minimizing deposit formation on the membrane surface.

  12. Progress in surface and membrane science

    CERN Document Server

    Cadenhead, D A

    1976-01-01

    Progress in Surface and Membrane Science, Volume 10 covers the advances in surface and membrane science. The book discusses the selective changes of cellular particles influencing sedimentation properties; and the rotating disk and ring-disk electrodes in investigations of surface phenomena at the metal-electrolyte interface. The text also describes the membrane potential of phospholipid bilayer and biological membranes; the adsorption of surfactant monolayers at gas/liquid and liquid/liquid interfaces; and the enzymes immobilized on glass. Chemists and people involved in electrochemistry will

  13. Membrane Buckling Induced by Curved Filaments

    Science.gov (United States)

    Lenz, Martin; Crow, Daniel J. G.; Joanny, Jean-François

    2009-07-01

    We present a novel buckling instability relevant to membrane budding in eukaryotic cells. In this mechanism, curved filaments bind to a lipid bilayer without changing its intrinsic curvature. As more and more filaments adsorb, newly added ones are more and more strained, which destabilizes the flat membrane. We perform a linear stability analysis of filament-dressed membranes and find that the buckling threshold is within reasonable in vivo parameter values. We account for the formation of long tubes previously observed in cells and in purified systems. We study strongly deformed dressed membranes and their bifurcation diagram numerically. Our mechanism could be validated by a simple experiment.

  14. Novel Tripod Amphiphiles for Membrane Protein Analysis

    DEFF Research Database (Denmark)

    Chae, Pil Seok; Kruse, Andrew C; Gotfryd, Kamil

    2013-01-01

    . The use of a detergent or other amphipathic agents is required to overcome the intrinsic incompatibility between the large lipophilic surfaces displayed by the membrane proteins in their native forms and the polar solvent molecules. Here, we introduce new tripod amphiphiles displaying favourable......Integral membrane proteins play central roles in controlling the flow of information and molecules across membranes. Our understanding of membrane protein structures and functions, however, is seriously limited, mainly due to difficulties in handling and analysing these proteins in aqueous solution...

  15. Tensile strain mapping in flat germanium membranes

    Energy Technology Data Exchange (ETDEWEB)

    Rhead, S. D., E-mail: S.Rhead@warwick.ac.uk; Halpin, J. E.; Myronov, M.; Patchett, D. H.; Allred, P. S.; Wilson, N. R.; Leadley, D. R. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Shah, V. A. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Department of Engineering, University of Warwick, Coventry, CV4 7AL (United Kingdom); Kachkanov, V.; Dolbnya, I. P. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Reparaz, J. S. [ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain); Sotomayor Torres, C. M. [ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain)

    2014-04-28

    Scanning X-ray micro-diffraction has been used as a non-destructive probe of the local crystalline quality of a thin suspended germanium (Ge) membrane. A series of reciprocal space maps were obtained with ∼4 μm spatial resolution, from which detailed information on the strain distribution, thickness, and crystalline tilt of the membrane was obtained. We are able to detect a systematic strain variation across the membranes, but show that this is negligible in the context of using the membranes as platforms for further growth. In addition, we show evidence that the interface and surface quality is improved by suspending the Ge.

  16. Tensile strain mapping in flat germanium membranes

    International Nuclear Information System (INIS)

    Rhead, S. D.; Halpin, J. E.; Myronov, M.; Patchett, D. H.; Allred, P. S.; Wilson, N. R.; Leadley, D. R.; Shah, V. A.; Kachkanov, V.; Dolbnya, I. P.; Reparaz, J. S.; Sotomayor Torres, C. M.

    2014-01-01

    Scanning X-ray micro-diffraction has been used as a non-destructive probe of the local crystalline quality of a thin suspended germanium (Ge) membrane. A series of reciprocal space maps were obtained with ∼4 μm spatial resolution, from which detailed information on the strain distribution, thickness, and crystalline tilt of the membrane was obtained. We are able to detect a systematic strain variation across the membranes, but show that this is negligible in the context of using the membranes as platforms for further growth. In addition, we show evidence that the interface and surface quality is improved by suspending the Ge

  17. Progress in surface and membrane science

    CERN Document Server

    Cadenhead, D A; Rosenberg, M D

    1974-01-01

    Progress in Surface and Membrane Science, Volume 8 covers the developments in the study of surface and membrane science. The book discusses the applications of statistical mechanics to physical adsorption; the impact of electron spectroscopy and cognate techniques on the study of solid surfaces; and the ellipsometric studies of thin films. The text also describes the interfacial photochemistry of bilayer lipid membranes; cell junctions and their development; and the composition and function of the inner mitochondrial membrane. The role of the cell surface in contact inhibition of cell division

  18. Membrane Technologies in Wine Industry: An Overview.

    Science.gov (United States)

    El Rayess, Youssef; Mietton-Peuchot, Martine

    2016-09-09

    Membrane processes are increasingly reported for various applications in wine industry such as microfiltration, electrodialysis, and reverse osmosis, but also emerging processes as bipolar electrodialysis and membrane contactor. Membrane-based processes are playing a critical role in the field of separation/purification, clarification, stabilization, concentration, and de-alcoholization of wine products. They begin to be an integral part of the winemaking process. This review will provide an overview of recent developments, applications, and published literature in membrane technologies applied in wine industry.

  19. Progress in surface and membrane science

    CERN Document Server

    Danielli, J F; Cadenhead, D A

    1972-01-01

    Progress in Surface and Membrane Science, Volume 5 covers the developments in the study of surface and membrane science. The book discusses the Mössbauer effect in surface science; the surface functional groups on carbon and silica; and the wetting phenomena pertaining to adhesion. The text also describes the physical state of phospholipids and cholesterol in monolayers, bilayers, and membranes; the characteristics of heterocoagulation; and the effects of calcium on excitable membranes and neurotransmitter action. Chemists, physiologists, biophysicists, and civil engineers will find the book i

  20. Increasing Diversity of Biological Membrane Fission Mechanisms.

    Science.gov (United States)

    Renard, Henri-François; Johannes, Ludger; Morsomme, Pierre

    2018-01-04

    Membrane fission is essential to life. It is required for many fundamental cellular processes, as diverse as cyto- and karyokinesis, organelle division, membrane repair, and membrane trafficking and endocytosis. While membrane fission was originally seen as resulting from the action of mechanoenzymes such as dynamin, it is clear that the reality is more complex. In this review, we propose an updated overview of fission mechanisms, and try to extract essential requirements for each. We also present examples of cellular processes that involve these fission mechanisms. Finally, we list pending questions, whether they are specific to a peculiar fission mechanism or more general to the field. Copyright © 2017 Elsevier Ltd. All rights reserved.