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951.
Christian Renicke Daniel Schuster Svetlana Usherenko Lars-Oliver Essen Christof Taxis 《Chemistry & biology》2013,20(4):619-626
Highlights? Optogenetic tool to control the stability of soluble and membrane proteins ? Engineered using the LOV2 domain and a murine ornithine decarboxylase-like degron ? Creation of light-switchable, conditional mutants ? Graded response to very low blue light intensities allows yeast photography 相似文献
952.
Ewelina Ciecierska Anna Boczkowska Krzysztof Jan Kurzydlowski Iosif Daniel Rosca Suong Van Hoa 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1019-1024
The paper concerns thermal properties of epoxy/nanotubes composites for aircraft application. In this work, influence of carbon nanotubes on thermal stability, thermal conductivity, and crosslinking density of epoxy matrix was determined. Three kinds of nanotubes were used: non-modified with 1- and 1.5-μm length, and 1-μm length modified with amino groups. Scanning electron microscopy observations were done for examining dispersion of nanotubes in the epoxy matrix. Glass transition temperature (T g) was readout from differential scanning calorimetry. From dynamic mechanical analysis, crosslinking density was calculated for epoxy and its composites. Also, thermogravimetric analysis was done to determine influence of nanotubes addition on thermal stability and decomposition process of composites. Activation energy was calculated from TGA curves by Flynn–Wall–Ozawa method. Thermal diffusivity was also measured. SEM images proved the uniform dispersion of carbon nanotubes without any agglomerates. It was found that nanotubes modified with amino groups lead to the increase of epoxy matrix crosslinking density. The significant increase in T g was also observed. On the other hand, addition of carbon nanotubes leads to the decrease of thermal stability of polymer due to the increase of thermal diffusivity. 相似文献
953.
Electrochemical determination of Hg(II) in aquatic solutions on bare and modified glassy carbon electrode (GCE) is reported. Optimizing the parameters used for a bare GCE, such as the electrolyte solution, the potential and time of deposition, resulted in linear response over a large range of Hg(II) concentrations (4–160 ppb) using linear sweep anodic stripping voltammetry. Modification of the electrode with 4,4′-disulfanediyldibenzenediazonium (DSBD) yielded a lowest detection limit of 1 ppb. Two procedures for DSBD synthesis are described for the first time, and the product was characterized by microanalysis, FTIR and 1H-NMR. The electrochemical attachment of DSBD to the electrode was studied and compared with the electrochemical behaviour of DSBD analogous molecules, i.e. 4-aminophenyl disulfide, p-aminothiophenol and phenyl disulfide. 相似文献
954.
Yan Li Dr. Kazuki Fukushima Dr. Daniel J. Coady Dr. Amanda C. Engler Dr. Shaoqiong Liu Yuan Huang Dr. John S. Cho Dr. Yi Guo Dr. Lloyd S. Miller Dr. Jeremy P. K. Tan Dr. Pui Lai Rachel Ee Dr. Weimin Fan Prof. Yi Yan Yang Dr. James L. Hedrick 《Angewandte Chemie (International ed. in English)》2013,52(2):674-678
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Marek Grzybowski Kamil Skonieczny Prof. Dr. Holger Butenschön Prof. Dr. Daniel T. Gryko 《Angewandte Chemie (International ed. in English)》2013,52(38):9900-9930
Does the dehydrogenative coupling of aromatic compounds mediated by AlCl3 at high temperatures and also by FeCl3, MoCl5, PIFA, or K3[Fe(CN)6] at room temperature proceed by the same mechanism in all cases? With the growing importance of the synthesis of aromatic compounds by double C? H activation to give various biaryl structures, this question becomes pressing. Since some of these reactions proceed only in the presence of non‐oxidizing Lewis acids and some only in the presence of certain oxidants, the authors venture the hypothesis that, depending on the electronic structure of the substrates and the nature of the “catalyst”, two different mechanisms can operate. One involves the intermediacy of a radical cation and the other the formation of a sigma complex between the acid and the substrate. The goal of this Review is to encourage further mechanistic studies hopefully leading to an in‐depth understanding of this phenomenon. 相似文献
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