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41.
Phenyl‐γ‐valerolactones,flavan‐3‐ol colonic metabolites,protect brown adipocytes from oxidative stress without affecting their differentiation or function 下载免费PDF全文
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43.
Hoyoux A Blaise V Collins T D'Amico S Gratia E Huston AL Marx JC Sonan G Zeng Y Feller G Gerday C 《Journal of Bioscience and Bioengineering》2004,98(5):317-330
Cold-loving or psychrophilic organisms are widely distributed in nature as a large part of the earth's surface is at temperatures around 0 degrees C. To maintain metabolic rates and to prosper in cold environments, these extremophilic organisms have developed a vast array of adaptations. One main adaptive strategy developed in order to cope with the reduction of chemical reaction rates induced by low temperatures is the synthesis of cold-adapted or psychrophilic enzymes. These enzymes are characterized by a high catalytic activity at low temperatures associated with a low thermal stability. A study of protein adaptation strategies suggests that the high activity of psychrophilic enzymes could be achieved by the destabilization of the active site, allowing the catalytic center to be more flexible at low temperatures, whereas other protein regions may be destabilized or as rigid as their mesophilic counterparts. Due to these particular properties, psychrophilic enzymes offer a high potential not only for fundamental research but also for biotechnological applications. 相似文献
44.
Dr. Ilhem Khelifi Shannon Pecnard Dr. Guillaume Bernadat Dr. Jérome Bignon Dr. Hélène Levaique Dr. Joëlle Dubois Dr. Olivier Provot Dr. Mouad Alami 《ChemMedChem》2020,15(16):1571-1578
In this article, we report the synthesis and biological properties of a series of novel oxazepines related to isoCA-4 having significant antitumor properties. Among them, three oxazepin-9-ol derivatives display a nanomolar or a sub-nanomolar cytotoxicity level against five human cancer cell lines (HCT116, U87, A549, MCF7, and K562). It was demonstrated that the lead compound in this series inhibits tubulin assembly with an IC50 value of 1 μM and totally arrests the cellular cycle in the G2/M phase at the low concentration of 5 nM in HCT116 and K562 cells. Molecular modeling studies perfectly corroborates these promising results. 相似文献
45.
Amédée Djemai Etienne Balan Guillaume Morin Giancarlo Hernandez Jean Claude Labbe Jean Pierre Muller 《Journal of the American Ceramic Society》2001,84(5):1017-1024
Kaolinites with various degrees of structural order and iron content were heated and subsequently analyzed via electron paramagnetic resonance. Iron was present in two different states in the heated materials, either as dilute structural Fe3+ ions or in concentrated Fe3+ phases. During metakaolinization, the environment of dilute Fe3+ ions changed, following modifications of the Al3+ coordination, and the Fe3+ concentration increased. With the breakdown of metakaolinite, the diffusion of Fe3+ ions induced their exsolution in superparamagnetic iron-rich domains (Fe3+ clusters in γ-Al2 O3 and/or Fe3+ oxide nanophases), which produced a decrease in the dilute Fe3+ concentration. The subsequent breakdown of γ-Al2 O3 and the formation of mullite made the dilute Fe3+ concentration increase again, because of the incorporation of Fe3+ ions in the mullite structure. 相似文献
46.
The cone calorimeter is one of the major fire tests. In its reference standard ISO 5660‐1, the apparatus (and especially a characteristic of its orifice plate mass flow meter, called C‐Factor) is calibrated using a methane burner set at 5 kW. However, measurements performed in end‐use are in the range 1–10 kW. In addition, standard proposes to check linearity at 1 and 3 kW, which means in the lowest part of the range. This communication establishes the validation of the linearity on the whole range and determines the optimal condition for C‐factor determination. It justifies the technical choices of the standard. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
47.
Guillaume Duflos François Leduc Assi N'Guessan Frederic Krzewinski Ossarath Kol Pierre Malle 《Journal of the science of food and agriculture》2010,90(15):2568-2575
BACKGROUND: The freshness of whiting was studied at five stages of ice storage by comparing the analysis of volatile compounds obtained through solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) with two sensory methods. RESULTS: Of the volatile compounds identified, 38 were analysed using a statistical multivariate approach and classified according to their role in the estimation of freshness during storage as markers of freshness or spoilage. Regarding the evolution of the presence or absence of individual compounds, three categories were defined. For example, the volatile compounds propanal, hexanal, 1‐penten‐3‐ol, pentanal, 2,3‐pentanedione, 1‐penten‐3‐one, heptanal, (E)‐2‐pentenal, 2,3‐octanedione, (Z)‐2‐penten‐1‐ol, 1‐pentanol, butanal, octanal, 3,5,5‐trimethyl‐2‐hexene, 1‐hexanol and 4,4‐dimethyl‐1,3‐dioxane appeared highly relevant, because they are found throughout storage and can be divided into several categories that are directly related to the quality of fish. CONCLUSION: SPME/GC/MS combined with a statistical multivariate approach may be a useful method to identify volatile compounds and characterise fish freshness during storage. Copyright © 2010 Society of Chemical Industry 相似文献
48.
Nicolas RousselLucile Lallemant Bernard Durand Sophie GuillemetJean-Yves Chane Ching Gilbert Fantozzi Vincent Garnier Guillaume Bonnefont 《Ceramics International》2011,37(8):3565-3573
A slurry of α-Al2O3 was doped with Mg, Zr and La nitrates or chlorides, in various amounts in the range 150-500 wt ppm and then freeze-dried to produce nanosized doped powder (∼150 nm). The powder was sintered by SPS to yield transparent polycrystalline alpha alumina. The influence of the nature of the doping element and the starting salt, the thermal treatment before sintering and the sintering temperature on the transparency of the ceramics were investigated. The transparency of the ceramics of nanosized Al2O3 was shown to depend mainly on the way the powder was prepared, the nature of the doping salt also had an effect. Finally, a high real inline transmittance, reaching 48.1% was achieved after optimization. 相似文献
49.
Potié A Baron T Dhalluin F Rosaz G Salem B Latu-Romain L Kogelschatz M Gentile P Oehler F Montès L Kreisel J Roussel H 《Nanoscale research letters》2011,6(1):187-9
The growth of semiconductor (SC) nanowires (NW) by CVD using Au-catalyzed VLS process has been widely studied over the past few years. Among others SC, it is possible to grow pure Si or SiGe NW thanks to these techniques. Nevertheless, Au could deteriorate the electric properties of SC and the use of other metal catalysts will be mandatory if NW are to be designed for innovating electronic. First, this article's focus will be on SiGe NW's growth using Au catalyst. The authors managed to grow SiGe NW between 350 and 400°C. Ge concentration (x) in Si1-xGex NW has been successfully varied by modifying the gas flow ratio: R = GeH4/(SiH4 + GeH4). Characterization (by Raman spectroscopy and XRD) revealed concentrations varying from 0.2 to 0.46 on NW grown at 375°C, with R varying from 0.05 to 0.15. Second, the results of Si NW growths by CVD using alternatives catalysts such as platinum-, palladium- and nickel-silicides are presented. This study, carried out on a LPCVD furnace, aimed at defining Si NW growth conditions when using such catalysts. Since the growth temperatures investigated are lower than the eutectic temperatures of these Si-metal alloys, VSS growth is expected and observed. Different temperatures and HCl flow rates have been tested with the aim of minimizing 2D growth which induces an important tapering of the NW. Finally, mechanical characterization of single NW has been carried out using an AFM method developed at the LTM. It consists in measuring the deflection of an AFM tip while performing approach-retract curves at various positions along the length of a cantilevered NW. This approach allows the measurement of as-grown single NW's Young modulus and spring constant, and alleviates uncertainties inherent in single point measurement. 相似文献
50.
Renaud Metz Loic Boudehen Said Tahir Ty Phou Guillaume Prevost Remi Jelinek Philippe Dieudonné Merdad Hassanzadeh 《International Journal of Applied Ceramic Technology》2017,14(2):274-281
The recycling process toward the elimination of varistor wastes into new electro‐active silicon composites has been investigated. We studied the dependence of the E‐J characteristics on the aggregate content in the polymer matrix. Formulations with 40 vol.% metal oxide varistor aggregates in the 100‐200 μm range exhibit reliable nonlinear behavior with a switching voltage of 280±30 V/mm. The breakdown voltage of the composite decreases as both filler's diameter and filler's volume fraction increases in the 550‐220 V/mm and 440‐280 V/mm range, respectively. This paves the way for the valorization of varistors based zinc oxide (ZnO) ceramics. 相似文献