Auswahl der wissenschaftlichen Literatur zum Thema „ETFE membrána“

Background: Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) is a congenital rare metabolic disease with broad clinical phenotypes and variable evolution. This inborn error of metabolism is caused by mutations in the ETFA, ETFB or ETFDH genes, which encode for the mitochondrial ETF and ETF:QO proteins. A considerable group of patients has been described to respond positively to riboflavin oral supplementation, which constitutes the prototypic treatment for the pathology. Objectives: To report mutations in ETFA, ETFB and ETFDH genes identified in Portuguese patients, correlating, whenever possible, biochemical and clinical outcomes with the effects of mutations on the structure and stability of the affected proteins, to better understand MADD pathogenesis at the molecular level. Methods: MADD patients were identified based on the characteristic urinary profile of organic acids and/or acylcarnitine profiles in blood spots during newborn screening. Genotypic, clinical and biochemical data were collected for all patients. In silico structural analysis was employed using bioinformatic tools carried out in an ETF:QO molecular model for the identified missense mutations. Results: A survey describing clinical and biochemical features of eight Portuguese MADD patients was made. Genotype analysis identified five ETFDH mutations, including one extension (p.X618QextX*14), two splice mutations (c.34+5G>C and c.405+3A>T) and two missense mutations (ETF:QO-p.Arg155Gly and ETF:QO-p.Pro534Leu), and one ETFB mutation (ETFβ- p.Arg191Cys). Homozygous patients containing the ETFDH mutations p.X618QextX*14, c.34+5G>C and ETF:QO-p.Arg155Gly, all presented severe (lethal) MADD phenotypes. However, when any of these mutations are in heterozygosity with the known ETF:QO-p.Pro534Leu mild variant, the severe clinical effects are partly and temporarily attenuated. Indeed, the latter destabilizes an ETF-interacting loop, with no major functional consequences. However, the position 155 in ETF:QO is localized at the ubiquinone binding and membrane interacting domain, and is thus expected to perturb protein structure and membrane insertion, with severe functional effects. Structural analysis of molecular models is therefore demonstrated to be a valuable tool to rationalize the effects of mutations in the context of the clinical phenotype severity. Conclusion: Advanced molecular diagnosis, structural analysis and clinical correlations reveal that MADD patients harboring a severe prognosis mutation in one allele can actually revert to a milder phenotype by complementation with a milder mutation in the other allele. However, such patients are nevertheless in a precarious metabolic balance which can revert to severe fatal outcomes during catabolic stress or secondary pathology, thus requiring strict clinical follow-up.

ABSTRACT The anaerobic acetogenic bacterium Acetobacterium woodii couples caffeate reduction with electrons derived from hydrogen to the synthesis of ATP by a chemiosmotic mechanism with sodium ions as coupling ions, a process referred to as caffeate respiration. We addressed the nature of the hitherto unknown enzymatic activities involved in this process and their cellular localization. Cell extract of A. woodii catalyzes H2-dependent caffeate reduction. This reaction is strictly ATP dependent but can be activated also by acetyl coenzyme A (CoA), indicating that there is formation of caffeyl-CoA prior to reduction. Two-dimensional gel electrophoresis revealed proteins present only in caffeate-grown cells. Two proteins were identified by electrospray ionization-mass spectrometry/mass spectrometry, and the encoding genes were cloned. These proteins are very similar to subunits α (EtfA) and β (EtfB) of electron transfer flavoproteins present in various anaerobic bacteria. Western blot analysis demonstrated that they are induced by caffeate and localized in the cytoplasm. Etf proteins are known electron carriers that shuttle electrons from NADH to different acceptors. Indeed, NADH was used as an electron donor for cytosolic caffeate reduction. Since the hydrogenase was soluble and used ferredoxin as an electron acceptor, the missing link was a ferredoxin:NAD+ oxidoreductase. This activity could be determined and, interestingly, was membrane bound. A search for genes that could encode this activity revealed DNA fragments encoding subunits C and D of a membrane-bound Rnf-type NADH dehydrogenase that is a potential Na+ pump. These data suggest the following electron transport chain: H2 → ferredoxin → NAD+ → Etf → caffeyl-CoA reductase. They also imply that the sodium motive step in the chain is the ferredoxin-dependent NAD+ reduction catalyzed by Rnf.

ETFE is the abbreviation of Ethylen Tetra Fluoro Etylene, a sort of colorless and transparent granules. The advantage ETFE film has daylight transmission and chemical resistance, the aging resistance and lightweight. The thickness of ETFE film is used to from 50μm to 300μm and tensile strength of ETFE film changes from 40MPa to 60MPa and the tensile strain at break can get to about 300-400%. In this paper, ETFE film carried out the tensile proprieties, such as the tensile strain at break, the tensile strength are examined.

The electron-transferring flavoprotein-menaquinone oxidoreductase ABCX (EtfABCX), also known as FixABCX for its role in nitrogen-fixing organisms, is a member of a family of electron-transferring flavoproteins that catalyze electron bifurcation. EtfABCX enables endergonic reduction of ferredoxin (E°′ ∼−450 mV) using NADH (E°′ −320 mV) as the electron donor by coupling this reaction to the exergonic reduction of menaquinone (E°′ −80 mV). Here we report the 2.9 Å structure of EtfABCX, a membrane-associated flavin-based electron bifurcation (FBEB) complex, from a thermophilic bacterium. EtfABCX forms a superdimer with two membrane-associated EtfCs at the dimer interface that contain two bound menaquinones. The structure reveals that, in contrast to previous predictions, the low-potential electrons bifurcated from EtfAB are most likely directly transferred to ferredoxin, while high-potential electrons reduce the quinone via two [4Fe-4S] clusters in EtfX. Surprisingly, EtfX shares remarkable structural similarity with mammalian [4Fe-4S] cluster-containing ETF ubiquinone oxidoreductase (ETF-QO), suggesting an unexpected evolutionary link between bifurcating and nonbifurcating systems. Based on this structure and spectroscopic studies of a closely related EtfABCX, we propose a detailed mechanism of the catalytic cycle and the accompanying structural changes in this membrane-associated FBEB system.

The tensile test specimens of ETFE (ethylene - tetrafluoroethylene copolymer) membrane have been done at 7 temperatures. It is obtained corresponding stress - strain tensile curve, tensile strength and breaking elongation. Through experiments, it is given the tensile curves at different temperatures to determine turning points on the two rigid method, which has been a turning point corresponding to the yield stress and strain; and it is given ETFE calculation of elastic modulus by tensile curve calculate the tangent modulus, secant modulus, elastic modulus of the second and third; through numerical calculation, it is measured the energy performance of ETFE membranes. The results of the experiments provide a theoretical basis of ETFE membrane to study the architecture.

There are hundreds of essential genes in multidrug-resistant bacterial genomes, but only a few of their products are exploited as antibacterial targets. An example is the electron transfer flavoprotein (ETF), which is required for growth and viability in Burkholderia cenocepacia. Here, we evaluated ETF as an antibiotic target for Burkholderia cepacia complex (Bcc). Depletion of the bacterial ETF during infection of Caenorhabditis elegans significantly extended survival of the nematodes, proving that ETF is essential for survival of B. cenocepacia in this host model. In spite of the arrest in respiration in ETF mutants, the inhibition of etf expression did not increase the formation of persister cells, when treated with high doses of ciprofloxacin or meropenem. To test if etf translation could be inhibited by RNA interference, antisense oligonucleotides that target the etfBA operon were synthesized. One antisense oligonucleotide was effective in inhibiting etfB translation in vitro but not in vivo, highlighting the challenge of reduced membrane permeability for the design of drugs against B. cenocepacia. This work contributes to the validation of ETF of B. cenocepacia as a target for antibacterial therapy and demonstrates the utility of a C. elegans liquid killing assay to validate gene essentiality in an in vivo infection model.

The enclosed air plays a significant role in form-finding and loading analysis of ETFE cushions. A new numerical model of ETFE cushions is proposed in order to consider the interaction effects between outer membrane and internal air. Then the form-finding and loading analysis of a regular hexagon ETFE cushion are performed and compared with experimental study. It is shown that the numerical results are in good agreement with the test results. The interaction FE model can be used in static analysis of ETFE cushions.

Ehrlichia chaffeensis, an obligatory intracellular bacterium, infects monocytes/macrophages by sequestering a regulator of endosomal traffic, the small GTPase RAB5, on its membrane-bound inclusions to avoid routing to host-cell phagolysosomes. How RAB5 is sequestered on ehrlichial inclusions is poorly understood, however. We found that nativeEhrlichiatranslocated factor-2 (Etf-2), a previously predicted effector of theEhrlichiatype IV secretion system, and recombinant Etf-2 (cloned into theEhrlichiagenome) are secreted into the host-cell cytoplasm and localize to ehrlichial inclusions. Ectopically expressed Etf-2–GFP also localized to inclusions and membranes of early endosomes marked with RAB5 and interacted with GTP-bound RAB5 but not with a GDP-bound RAB5. Etf-2, although lacking a RAB GTPase-activating protein (GAP) Tre2-Bub2-Cdc16 (TBC) domain, contains two conserved TBC domain motifs, namely an Arg finger and a Gln finger, and site-directed mutagenesis revealed that both Arg188and Gln245are required for Etf-2 localization to early endosomes. The yeast two-hybrid assay and microscale thermophoresis revealed that Etf-2 binds tightly to GTP-bound RAB5 but not to GDP-bound RAB5. However, Etf-2 lacks RAB5-specific GAP activity. Etf-2 localized to bead-containing phagosomes as well as endosomes containing beads coated with the C-terminal fragment of EtpE (entry-triggering protein ofEhrlichia), anEhrlichiaouter-membrane invasin, and significantly delayed RAB5 dissociation from and RAB7 localization to phagosomes/endosomes and RABGAP5 localization to endosomes. Thus, binding of Etf-2 to RAB5-GTP appears to delay RAB5 inactivation by impeding RABGAP5 localization to endosomes. This suggests a unique mechanism by which RAB5 is sequestered on ehrlichial inclusions to benefit bacterial survival and replication.

Co-polymer facade materials have recently become a popular option in the building industry as an alternative to glazing. Ethylene Tetra-Fluoro-Ethylene (ETFE) foil has been successfully used in many projects as an innovative solution to energy-conscious design challenges. In addition, the use of ETFE membrane has resulted in significant savings in cost and structural support requirements, compared with conventional glazing, due to its low weight. There is a lack of detailed published data reporting its thermal behaviour. This study focuses on the examination of heat transfer through the ETFE membrane, and more specifically heat loss and solar gains. The document examines the impact of the material on the energy use of a building, as well as thermal comfort and interior conditions. Through field-testing and computer simulations the research evaluates the material’s thermal properties to obtain results that will assist in estimating the suitability of ETFE foil use in comparison to glass. Field-testing is used to perform a comparison of the thermal and energy behaviour of a fritted double ETFE cushion to a double glazed cover. The two experimental devices under examination present nearly identical energy consumption due to heating requirements. The experimental findings are implemented in Integrated Environmental Solutions (IES) and used to identify the necessary steps to accurately reproduce the thermal and energy behaviour associated with both covering materials. Further simulations were undertaken to provide a comparison of several types of ETFE cushions to various types of double glass. More specifically, the types examined are a clear double ETFE roof cover and a fritted double ETFE roof cover in comparison to a standard double glazed roof and a low-E double glazed roof. The roofs covers are examined in relation to energy requirements for both the heating and cooling of a space. Such an assessment of performance will provide information for further investigation to improve the material’s features and optimise energy performance.

Ce travail porte sur l'amélioration de la sélectivité préférentielle d'une membrane cationique à base d’ETFE pour une utilisation en électrodialyse afin de traiter des effluents industriels contenant un mélange d’acides et de sels métalliques. Pour cela, nous avons fait appel à la méthode de la modification chimique de la surface d’une membrane cationique par la formation d’un film superficiel mince portant des charges positives afin de former une barrière de répulsion électrostatique pour des cations bivalents tout en permettant le passage de cations monovalents tels que les protons.

La synthèse de la membrane cationique de base a été réalisée en passant par différentes étapes à savoir :le greffage du styrène - divinylbenzène (DVB), la chlorosulfonation et l’hydrolyse.

Au cours de ce travail, nous avons mis au point un protocole de greffage du styrène-DVB dans le film d’ETFE qui permet l’obtention d’un film ayant un taux de greffage reproductible assurant à la membrane cationique finale une bonne conductivité électrique et une capacité d’échange acceptable pour une membrane d’électrodialyse. Une étude de la réaction de greffage en fonction de la concentration en réticulant a été réalisée.

Nous avons procédé par la suite à la modification de la surface du film d’ETFE greffé styrène-DVB par la formation d’une couche superficielle mince fixée par des liens covalents. Les membranes modifiées ont été obtenues par la réaction d’une seule face du film d’ETFE greffé chlorosulfoné avec la 3-diméthylaminopropylamine. La modification chimique de la surface du film ETFE greffé chlorosulfoné a été suivie par la technique FTIR-ATR. L’effet de la concentration de la diamine sur les propriétés électrochimiques des différentes membranes modifiées a été étudié. La résistance électrique des membranes modifiées équilibrées au contact de solutions de chlorure de sodium et d'acide sulfurique a été mesurée par la technique d’impédance. La détermination du nombre de transport du proton et de l’ion sodium a été réalisée à partir de mesures du potentiel de membrane. La densité de courant limite des membranes a été évaluée sur base des courbes courant-tension. Les mesures de chronopotentiométrie ont été également effectuées sur les différentes membranes synthétisées.

Les résultats de ces caractérisations montrent que la modification de la surface engendre des changements considérables au niveau des propriétés électrochimiques des membranes résultantes. La résistance électrique, la densité de courant limite ainsi que les propriétés de transport de la membrane dépendent d’une part de la concentration de la diamine utilisée et d’autre part de la solution dans laquelle la membrane modifiée est équilibrée.

La sélectivité préférentielle des différentes membranes vis-à-vis des protons par rapport aux ions bivalents a été testée en réalisant des électrodialyses d’un milieu mixte H2SO4-NiSO4. Nos résultats montrent que la modification chimique de la surface de la membrane affecte d’une manière significative le transport des ions nickel tout en respectant le passage des protons. Une meilleure séparation a été obtenue pour une membrane modifiée en utilisant la diamine pure.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

L'objectiu de la present tesi és desenvolupar un sistema fotovoltaic per a ser integrat arquitectònicament que, basat en membranes polimèriques i cèl·lules orgàniques semitransparents, promogui la consecució d'edificis més eficients mitjançant la generació d'electricitat, el control lumínic i la millora de l'eficiència energètica dels tancaments semitransparents. Els sistemes solars integrats en edificis representen uns elements que compleixen una doble funció. D'una banda actuen com a element constructiu i de l'altra són elements generadors. Aquesta ambivalència els posiciona com a imprescindibles per complir els requisits establerts per la Comissió Europea en matèria d'eficiència energètica en edificis. El sistema objecte de la tesi pot ser inclòs en zones que requereixen un material translúcid o transparent com són finestres, lluernes o qualsevol tancament transparent. Normalment, els elements translúcids que trobem en la construcció d'edificis estan basats en vidre, encara que existeixen altres materials que poden oferir prestacions similars com són els polímers. Un polímer amb unes propietats molt adequades per a aquesta aplicació és l'etilè tetrafluoroetilè (ETFE). La integració de sistemes fotovoltaics en elements translúcids exigeix la necessitat d'una certa semitransparència, aquest fet ha propiciat que en els últims anys sigui una propietat molt estudiada en aquest camp de la física. Per explorar aquests avenços s'ha realitzat una revisió de les tecnologies fotovoltaiques semitransparents. Es va seleccionar la tecnologia fotovoltaica orgànica (OPV) per integrar-la conjuntament amb l'ETFE, ja que els avenços aconseguits en investigacions prèvies mostren que és la tecnologia més avançada i prometedora per a aquest fi. Per dur a terme l'anàlisi del nou sistema ETFE / OPV s'ha realitzat una caracterització dels diferents materials per determinar el seu comportament lumínic i elèctric. La caracterització lumínica de l'ETFE i de les OPV s'ha realitzat mesurant les seves propietats òptiques per a un espectre ample de fins a 50 micres, obtenint les principals característiques òptiques. Pel que fa a les OPV, s'ha realitzat una caracterització elèctrica en condicions reals d'operació, no només per determinar la seva eficiència sinó també la seva estabilitat. A partir d'aquí, s'ha pogut realitzar un model i simulació dinàmica d'un sistema ETFE / OPV pla que permet veure el grau d'aportació energètica, la influència en la demanda tèrmica i l'afectació en el confort lumínic a l'ésser integrat com a tancament translúcid. Finalment, partint de les propietats òptiques, s'ha realitzat un model numèric que permet determinar el comportament tèrmic i elèctric de les OPV incorporades en sistemes coixí multicapa d'ETFE.
El objetivo de la presente tesis es desarrollar un sistema fotovoltaico para ser integrado arquitectónicamente que, basado en membranas poliméricas y células orgánicas semitransparentes, promueva la consecución de edificios más eficientes mediante la generación de electricidad, el control lumínico y la mejora de la eficiencia energética de los cerramientos semitransparentes. Los sistemas solares integrados en edificios representan unos elementos que cumplen una doble función. Por un lado actúan como elemento constructivo y por el otro son elementos generadores. Esta ambivalencia les posición como imprescindibles para cumplir los requisitos establecidos por la comisión Europea en materia de eficiencia energética en edificios. El sistema objeto de la tesis pueden ser incluido en zonas que requieren un material translucido o transparente como son ventanas, tragaluces o cualquier cerramiento transparente. Normalmente, los elementos translucidos que encontramos en la construcción de edificios están basados en vidrio, aunque existen otros materiales que pueden ofrecer prestaciones similares como son los polímeros. Un polímero con unas propiedades muy adecuadas para esta aplicación es el etileno tetrafluoroetileno (ETFE). La integración de sistemas fotovoltaicos en elementos translucidos exige la necesidad de cierta semitrasnparencia, este hecho ha propiciado que en los últimos años sea una propiedad muy estudiada en este campo de la física. Para explorar estos avances se ha realizado una revisión de las tecnologías fotovoltaicas semitransparentes. Se seleccionó la tecnología fotovoltaica orgánica (OPV) para integrarla conjuntamente con el ETFE, ya que los avances logrados en investigaciones previas muestran que es la tecnología más avanzada y prometedora para este fin. Para llevar a cabo el análisis del nuevo sistema ETFE/OPV se ha realizado una caracterización de los diferentes materiales para determinar su comportamiento lumínico y eléctrico. La caracterización lumínica del ETFE y de las OPVs se ha realizado midiendo sus propiedades ópticas para un espectro ancho de hasta 50 μm, obteniéndose las principales características ópticas. Referente a las OPVs, se ha realizado una caracterización eléctrica en condiciones reales de operación, no solo para determinar su eficiencia sino también su estabilidad. A partir de aquí, se ha podido realizar un modelo y simulación dinámica de un sistema ETFE/OPV plano que permite ver el grado de aportación energética, la influencia en la demanda térmica y la afectación en el confort lumínico al ser integrado como cerramiento translucido. Finalmente, partiendo de las propiedades ópticas, se ha realizado un modelo numérico que permite determinar el comportamiento térmico y eléctrico de las OPVs incorporadas en sistemas cojín multicapa de ETFE.
The objective of this thesis is to develop a photovoltaic system to be building integrated that, based on polymeric membranes and semi-transparent organic cells, promotes the achievement of more efficient buildings through the generation of electricity, light control and the improvement of energy efficiency in semitransparent glazing. Solar systems integrated in buildings represent elements that serve a dual function. On the one hand, they act as a constructive element and, on the other hand, they are generating elements. This ambivalence positions them as essential to meet the requirements established by the European Commission regarding energy efficiency in buildings. The system object of the thesis can be included in zones that require a translucent or transparent material such as windows, skylights or any transparent enclosure. Normally, the translucent elements that we find in the construction of buildings are based on glass, albeit other materials that can offer similar benefits such as polymers exist. A polymer with very suitable properties for this application is ethylene tetrafluoroethylene (ETFE). The integration of photovoltaic systems in translucent elements requires certain semitransparency, this fact has led the transparency to be a property that has been widely studied in this field of physics in recent years. To explore these advances, a review of semitransparent photovoltaic technologies has been carried out. Organic photovoltaic (OPV) technology was selected to be integrated together with ETFE, since the advances made in previous research did show that it is the most advanced and promising technology to this purpose. In order to perform an analysis of the new ETFE / OPV system, a characterization of the different materials has been conducted to determine their luminous and electrical performance. The luminous characterization of ETFE and OPVs has been carried out by measuring their optical properties for a wide spectrum of up to 50 μm, obtaining the main optical characteristics. Regarding the OPVs, an electrical characterization has been executed under real operating conditions, not only to determine its efficiency but also its stability. From here, it has been possible to build a model for the dynamic simulation of a flat ETFE/OPV system that reveals the degree of energy input, the influence on thermal demand and the effect on light comfort when the system is integrated as a translucent glazing. Finally, based on the optical properties, a numerical model has been implemented that allows determining the thermal and electrical behavior of the OPVs incorporated in ETFE multilayer cushion systems.

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The current global water crisis makes awareness of the problem of its finiteness present in discussion, whether governmental, private, research, ecology or sustainability. The search for better forms of consumption and alternatives of treatment and production of reuse water is increasing importance and intensifying studies in those areas. The objective of this work was to analyze membrane filtration techniques for the treatment of sewage effluents generated by ETE, verifying the technical and economic feasibility of improving the quality of reuse water production in Brazil, specifically in the State of São Paulo, verifying the technical and economic viability. This state was selected because, in the years 2014 and 2015, it experienced an atypical drought that presented low rainfall indices that had not been counted for decades, resulting in a possible rationing of water for the population. An exploratory research was carried out about filter membranes and their applications and an on - site interview with the technical lider of a large sanitation company that produces reuse water from sanitary effluents with a quality 50% higher than required by the standards of potability using this technology. The results of this work indicated positive estimates for the investment in the use of filter membranes for the production of reuse water. Its cost in the plant was estimated at 0.10 R$ / m3 and the average sale price of 1,70 R$ / m3, allowing financial savings for the final consumer, in this case 90.26% / m3, and for the investor, according to those estimates, an attractive return on investment, with a payback of 7.31 years, for a 41-year contract.
A atual crise mundial de água faz com que a conscientização sobre o problema de sua finidade esteja presente em discussões, sejam elas governamentais, da iniciativa privada, de pesquisas, ecologia ou sustentabilidade. A busca por melhores formas de consumo e alternativas de tratamento e produção de água de reuso vem ganhando importância e intensificando os estudos nestas áreas. Este trabalho teve por objetivo analisar as técnicas de filtragem por membranas para tratamento dos efluentes de esgoto sanitário gerados por Estação de Tratamento de Esgoto (ETE), verificando a viabilidade técnica e econômica na melhoria da qualidade da produção de água de reuso no Brasil, especificamente no Estado de São Paulo. Este Estado foi selecionado porque, nos anos de 2014 e 2015, passou por uma estiagem atípica que apresentou reduzidos índices pluviométricos não contabilizados há décadas, resultando em um possível racionamento de água para a população. Foi realizada uma pesquisa exploratória sobre membranas filtrantes e suas aplicações e uma entrevista in loco com o responsável técnico de uma grande empresa de saneamento, que produz água de reuso á partir de efluentes sanitários com uma qualidade 50% superior ao exigido pelos padrões de potabilidade, utilizando esta tecnologia. Os resultados deste trabalho indicaram estimativas favoráveis para o investimento na utilização de membranas filtrantes para a produção de água de reuso. O seu custo na planta foi estimado em 0,10 R$ / m3 e o preço médio de venda de 1,70 R$ / m3, permitindo economia financeira para o consumidor final, neste caso de 90,26 % / m3, e para o investidor, por estas estimativas, um retorno de investimento atrativo, com payback em 7,31 anos, para um contrato de 41 anos.