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101.
Florian Weyland Thorsten Eisele Sebastian Steiner Till Frömling George A. Rossetti Jürgen Rödel Nikola Novak 《Journal of the European Ceramic Society》2018,38(2):551-556
The stability of the electrocaloric effect under electric field cycling is an important consideration in the development of solid-state cooling devices. Here we report measurements carried out on Ba(Zr0.2Ti0.8)O3 ceramics which reveal that the adiabatic temperature change, polarization-electric field hysteresis loops and dielectric permittivity/loss show stable behavior up to 105 cycles. We further demonstrate that the loss in electrocaloric response observed after 105 cycles is associated with the migration of oxygen vacancies. As a result, the electrical properties of the material are changed leading to an increase in leakage current and Joule heating. Reversing the polarity of the electric field after every 105 cycles changes the migration direction of oxygen vacancies, thereby preventing charge accumulation at grain boundaries and electrodes. By doing so, the electrocaloric stability is improved and the adiabatic temperature remains constant even after 106 cycles, much higher than achieved in commercially available barium titanate ceramics. 相似文献
102.
Olive mill wastewater (OMW) is obtained as byproduct of oil production in large quantities after the olive harvest, mainly in the Mediterranean region. One problem is the high load of organic matter, such as phytotoxic polyphenols, which causes significant environmental problems. However, due to their antioxidant properties the use of these polyphenols is also popular in several industry branches, e.g. production of plastics, cosmetics and drugs. A combined wastewater treatment permits besides water purification also recovery of the polyphenolic compounds for industrial use. One possibility is membrane technology. An overview of research studies concerning polyphenol recovery from OMW using membrane technologies is given. 相似文献
103.
Back Cover: On the Influence of the Protonation States of Active Site Residues on AChE Reactivation: A QM/MM Approach (ChemBioChem 7/2017) 下载免费PDF全文
104.
Mutation of Conserved Residues Increases in Vitro Activity of the Formylglycine‐Generating Enzyme 下载免费PDF全文
Matthias Knop Roxana Lemnaru Prof. Dr. Florian P. Seebeck 《Chembiochem : a European journal of chemical biology》2017,18(17):1755-1761
The formylglycine‐generating enzyme (FGE) recognizes proteins with a specific cysteine‐containing six‐amino‐acid motif and converts this cysteine residue into formylglycine. The resulting aldehyde function provides a unique handle for selective protein labeling. We have identified two mutations in FGE from Thermomonospora curvata that increase this catalytic efficiency more than 40‐fold. The resulting activity and stability, as well as its ease of recombinant production, make this FGE variant a practical reagent for in vitro protein engineering. 相似文献
105.
Dr. Matthias Hauf Dr. Florian Richter Tobias Schneider Thomas Faidt Dr. Berta M. Martins Dr. Tobias Baumann Dr. Patrick Durkin Prof. Dr. Holger Dobbek Prof. Dr. Karin Jacobs Prof. Dr. Andreas Möglich Prof. Dr. Nediljko Budisa 《Chembiochem : a European journal of chemical biology》2017,18(18):1771-1771
106.
Sorption and desorption properties of random copolymer hydrogels of N‐isopropylacrylamide and N‐ethylacrylamide: Effect of monomer composition 下载免费PDF全文
Random copolymer hydrogels of N‐isopropylacrylamide and N‐ethylacrylamide (NEAM) were prepared using different monomer compositions in 1:1 methanol–water mixtures. The samples were characterized by cononsolvency study in methanol‐water mixtures at various temperatures, swelling properties measurements, scanning electron microscopy. With changing ratio of the monomers in the reaction mixture, the thermal, morphological and swelling properties, varied significantly. The change in the properties with monomer composition variation are interpreted based on the different thermoresponsive characteristics and interactions of gels of N‐isopropylacrylamide and NEAM (homo‐ and copolymer gels) in water and different methanol‐water mixtures, their variable compositions in the synthesis mixtures, and their morphologies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45176. 相似文献
107.
Florian Witzgall Wiebke Ewert Prof. Dr. Wulf Blankenfeldt 《Chembiochem : a European journal of chemical biology》2017,18(20):2045-2055
Pseudomonas aeruginosa, a prevalent pathogen in nosocomial infections and a major burden in cystic fibrosis, uses three interconnected quorum-sensing systems to coordinate virulence processes. At variance with other Gram-negative bacteria, one of these systems relies on 2-alkyl-4(1H)-quinolones (Pseudomonas quinolone signal, PQS) and might hence be an attractive target for new anti-infective agents. Here we report crystal structures of the N-terminal domain of anthranilate-CoA ligase PqsA, the first enzyme of PQS biosynthesis, in complex with anthraniloyl-AMP and with 6-fluoroanthraniloyl-AMP (6FABA-AMP) at 1.4 and 1.7 Å resolution. We find that PqsA belongs to an unrecognized subfamily of anthranilate-CoA ligases that recognize the amino group of anthranilate through a water-mediated hydrogen bond. The complex with 6FABA-AMP explains why 6FABA, an inhibitor of PQS biosynthesis, is a good substrate of PqsA. Together, our data might pave a way to new pathoblockers in P. aeruginosa infections. 相似文献
108.
Abstract
The kinetics of ammonia oxidation with oxygen over a Rh(110) surface were studied in the pressure range 10−5–10−4 mbar. Nitrogen was found to be the preferred product at low partial pressures ratios \textp\texto 2 :\textp\textNH 3 {\text{p}}_{{{\text{o}}_{ 2} }} :{\text{p}}_{{{\text{NH}}_{ 3} }} , while the NO pathway was favored with oxygen rich gas mixtures and at high temperature. The reactive sticking coefficient of O2 reaches up to 0.05 under steady state conditions. Pronounced hysteresis effects in the reaction rates were found in T-cycling experiments. Sustained oscillations in the reaction rates occurred under isothermal conditions at T = 620 K at a total pressure of 4 × 10−5 mbar. 相似文献109.
Manfred Lamprecht Simon Bogner Gert Schippinger Kurt Steinbauer Florian Fankhauser Seth Hallstroem Burkhard Schuetz Joachim F Greilberger 《Journal of the International Society of Sports Nutrition》2012,9(1):1-13
Background
Probiotics are an upcoming group of nutraceuticals claiming positive effects on athlete??s gut health, redox biology and immunity but there is lack of evidence to support these statements.Methods
We conducted a randomized, double-blinded, placebo controlled trial to observe effects of probiotic supplementation on markers of intestinal barrier, oxidation and inflammation, at rest and after intense exercise. 23 trained men received multi-species probiotics (1010 CFU/day, Ecologic?Performance or OMNi-BiOTiC?POWER, n?=?11) or placebo (n?=?12) for 14?weeks and performed an intense cycle ergometry over 90 minutes at baseline and after 14?weeks. Zonulin and ??1-antitrypsin were measured from feces to estimate gut leakage at baseline and at the end of treatment. Venous blood was collected at baseline and after 14?weeks, before and immediately post exercise, to determine carbonyl proteins (CP), malondialdehyde (MDA), total oxidation status of lipids (TOS), tumor necrosis factor-alpha (TNF-??), and interleukin-6 (IL-6). Statistical analysis used multifactorial analysis of variance (ANOVA). Level of significance was set at p?<?0.05, a trend at p?<?0.1.Results
Zonulin decreased with supplementation from values slightly above normal into normal ranges (<30?ng/ml) and was significantly lower after 14?weeks with probiotics compared to placebo (p?=?0.019). We observed no influence on ??1-antitrypsin (p?>?0.1). CP increased significantly from pre to post exercise in both groups at baseline and in the placebo group after 14?weeks of treatment (p?=?0.006). After 14?weeks, CP concentrations were tendentially lower with probiotics (p?=?0.061). TOS was slightly increased above normal in both groups, at baseline and after 14?weeks of treatment. There was no effect of supplementation or exercise on TOS. At baseline, both groups showed considerably higher TNF-?? concentrations than normal. After 14?weeks TNF-?? was tendentially lower in the supplemented group (p?=?0.054). IL-6 increased significantly from pre to post exercise in both groups (p?=?0.001), but supplementation had no effect. MDA was not influenced, neither by supplementation nor by exercise.Conclusions
The probiotic treatment decreased Zonulin in feces, a marker indicating enhanced gut permeability. Moreover, probiotic supplementation beneficially affected TNF-?? and exercise induced protein oxidation. These results demonstrate promising benefits for probiotic use in trained men.Clinical trial registry
http://www.clinicaltrials.gov, identifier: NCT01474629 相似文献110.
Cécile Vignal Muriel Pichavant Laurent Y. Alleman Madjid Djouina Florian Dingreville Esperanza Perdrix Christophe Waxin Adil Ouali Alami Corinne Gower-Rousseau Pierre Desreumaux Mathilde Body-Malapel 《Particle and fibre toxicology》2017,14(1):46