排序方式: 共有51条查询结果,搜索用时 62 毫秒
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S. Brioua K. Belmokre V. Debout P. Jacquot E. Conforto S. Touzain J. Creus 《Journal of Solid State Electrochemistry》2012,16(2):633-648
The corrosion behavior in artificial seawater of different as-sprayed ceramic-metallic (cermet) coatings applied on low-alloy
steel was studied. Five conditions, associated to modifications of the composition of the powder or deposition parameters
were evaluated. The degradation mechanisms were studied during extended immersion tests using conventional electrochemical
measurement and electrochemical impedance spectroscopy. The extended immersion tests reveal that these as-thermal-sprayed
coatings present a cathodic behavior compared with steel. During the first hours of immersion, the electrolyte infiltrates
the defects of the coatings, which then result to the local degradation of the substrate accelerated by the galvanic coupling
with the cermet coating. Optical observations and Raman analyses reveal the formation of calcium carbonates like aragonite
on the cermet surface, very close to the appearance of local anodic sites. The cross-sectioned views reveal the infiltration
of the corrosive solution, and the depth penetration of the degradation of steel substrate probably due to the acidification
of the anodic sites. 相似文献
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Inside Cover: Quinone‐Rich Poly(dopamine) Magnetic Nanoparticles for Biosensor Applications (ChemPhysChem 17/2014) 下载免费PDF全文
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L. Martínez E. RománJ.L. de Segovia S. PoupardJ. Creus F. Pedraza 《Applied Surface Science》2011,257(14):6202-6207
A surface study of electrodeposited cerium oxide based coatings is presented. Different surface analytical techniques were used in order to obtain complementary information to fully characterize such complex systems. X-ray Photoelectron Spectroscopy was used as the main technique to determine the surface composition of the coating. The analysis of the core level peaks of the elements provides additional information about the functional groups present on the surface. A mixture of Ce (III) and Ce (IV) was found in the coating and their proportion was calculated at different depths. The analysis of the O 1s core level peak revealed a triple structure whose origin will be discussed. To support the results obtained, electron stimulated desorption was performed. The study was completed with Auger electron spectroscopy and Raman spectroscopy, both techniques having different surface sensitivities. From all these results, it is derived that incomplete electrochemical reactions occurred during the growth of the coatings. This led to rather complex compositions, in which defective cerium oxides are the major species. In addition, hydroxides, carbonates and nitrates are also present, together with adsorbed water. 相似文献
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Zimbron JM Sardo A Heinisch T Wohlschlager T Gradinaru J Massa C Schirmer T Creus M Ward TR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(43):12883-12889
The mode of action of precious metal anticancer metallodrugs is generally believed to involve DNA as a target. However, the poor specificity of such drugs often requires high doses and leads to undesirable side-effects. With the aim of improving the specificity of a ruthenium piano-stool complex towards DNA, we employed a presenter protein strategy based on the biotin-avidin technology. Guided by the X-ray structure of the assembly of streptavidin and a biotinylated piano-stool, we explored the formation of metallodrug-mediated ternary complexes with the presenter protein and DNA. The assemblies bound more strongly to telomere G-quadruplexes than to double-stranded DNA; chemo-genetic modifications (varying the complex or mutating the protein) modulated binding to these targets. We suggest that rational targeting of small molecules by presenter proteins could be exploited to bind metallodrugs to preferred macromolecular targets. 相似文献
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L. Mendoza Zélis E. Crespo M. Creus L. C. Damonte F. H. Sánchez G. Punte 《Hyperfine Interactions》1994,83(1):289-292
Pure crystalline Hf and Fe powders were mixed and milled under an argon atmosphere. The evolution of the system with milling time was followed with Mössbauer effect spectroscopy and X-ray diffraction. The results indicate that in the first stages an amorphous Fe-rich alloy was gradually formed together with a solid solution of Hf in Fe beyond the solubility limit. 相似文献
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Pordea A Creus M Panek J Duboc C Mathis D Novic M Ward TR 《Journal of the American Chemical Society》2008,130(25):8085-8088
Nature's catalysts are specifically evolved to carry out efficient and selective reactions. Recent developments in biotechnology have allowed the rapid optimization of existing enzymes for enantioselective processes. However, the ex nihilo creation of catalytic activity from a noncatalytic protein scaffold remains very challenging. Herein, we describe the creation of an artificial enzyme upon incorporation of a vanadyl ion into the biotin-binding pocket of streptavidin, a protein devoid of catalytic activity. The resulting artificial metalloenzyme catalyzes the enantioselective oxidation of prochiral sulfides with good enantioselectivities both for dialkyl and alkyl-aryl substrates (up to 93% enantiomeric excess). Electron paragmagnetic resonance spectroscopy, chemical modification, and mutagenesis studies suggest that the vanadyl ion is located within the biotin-binding pocket and interacts only via second coordination sphere contacts with streptavidin. 相似文献
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Artificial metalloenzymes based on biotin-streptavidin technology, a "fusion" of chemistry and biology, illustrate how asymmetric catalysts can be improved and evolved using chemogenetic approaches. 相似文献