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排序方式: 共有216条查询结果,搜索用时 16 毫秒
1.
H.J.G. Broxterman P.A. Kooreman G.A. van der Marel J.H. van Boom 《Journal of carbohydrate chemistry》2013,32(3):287-307
ABSTRACT Easily accessible 1,6-anhydro-2,3-O-(S)-benzylidene-β-D-mannopyranose was converted in four steps to 1,6-anhydro-3,4-di-O-benzyl-β-D-talopyranose. Glycosylation of the latter with ethyl 2,3,4-tri-O-acetyl-1-thio-α-L-rhamnopyranoside gave, after further processing, 1-O-allyl-3,4-di-O-benzyl-2-O-(2,3,4-tri-O-benzyl-α-L-rhamnopyranosyl)-L-ribitol. 相似文献
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G.J.P.H. Boons R. Steyger M. Overhand G.A. van der Marel J.H. van Boom 《Journal of carbohydrate chemistry》2013,32(6):995-1007
ABSTRACT Diastereoselective hydroxymethylation of a suitably protected α-D-manno-hexodialdo-1,5-pyranoside with the Grignard reagent derived from (phenyldimethylsilyl)methyl chloride gives, after additional protecting group manipulations, an easy access to one donor and two acceptors of LD-Hepp. The latter derivatives could be applied successfully for the preparation of the disaccharides α-D-GlcpN-(1-7)-L-α-D-Hepp-OMe and L-α-D-Hepp-(1-6)-L-α-D-Hepp-OMe. 相似文献
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Yonatan Hamo Michal Lahav Milko E. van der Boom 《Angewandte Chemie (International ed. in English)》2020,59(7):2612-2617
We demonstrate controlled charge trapping and release, accompanied by multiple color changes in a metallo‐organic bilayer. The dual functionality of the metallo‐organic materials provides fundamental insight into the metal‐mediated electron transport pathways. The electrochemical processes are visualized by distinct, four color‐to‐color transitions: red, transparent, orange, and brown. The bilayer is composed of two elements: 1) a nanoscale gate consisting of a layer of well‐defined polypyridyl ruthenium complexes bound to a flexible transparent electrode, and 2) a charge storage layer consisting of isostructural iron complexes attached to the surface of the gate. This gate mediates or blocks electron transport in response to an applied voltage. The charge storage and release depend on the oxidation state of the layer of ruthenium complexes (=gate). Combining electrochemistry with optical data revealed mechanistic information: the brown coloration of the bilayer directly relates to the formation of intermediate ruthenium species, providing evidence for catalytic positive charge release mediated through the gate. 相似文献
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Nano titanium dioxide (nTiO2), generally considered to be toxicologically inert, is manufactured in large quantities and extensively applied in consumer products. The small size and large surface area endow them with an active group or intrinsic toxicity. Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of (bio) chemical applications. One of the great advantages of this technique is its ability to provide information on the concentration, structure and interaction of biochemical molecules in their microenvironments within intact cells and tissues, non-destructively. Zebrafish (Danio rerio), one of the most important vertebrate model organisms used in developmental biology, are increasingly used in biomedical research, particularly as a model of human disease. In the present work, an attempt is made to study the effect of titanium dioxide, both nano and bulk, on the microenvironment of the liver tissues of Zebrafish using FT-Raman spectroscopy. The results of the present study suggest that TiO2 exposure demonstrate a marked influence on the microenvironments of the liver tissues of Zebrafish. A shift to a higher wavenumber and an increase in the intensity of the band at ∼1087 cm−1 in the TiO2 exposed tissues suggest that some of the conformational changes resulting from the alkali recovery process takes place due to TiO2 exposure. The decreased intensity ratio (I3220/I3400) observed in the titanium-exposed tissues suggests a decreased water domain size, which could be interpreted in terms of weaker hydrogen-bonded molecular species of water in the TiO2 exposed tissues. The observed shift of COO− bands to higher frequencies shows the disruption of salt bridges as a result of a change in the oppositely charged partners and due to the enhanced random coil conformation. The variation in the intensity ratio of the tyrosyl doublet (I858/I825) indicates variation in the hydrogen bonding of the phenolic hydroxyl group due to TiO2 exposure. The results further suggest that the microenvironments are greatly altered due to titanium nano exposure when compared to titanium bulk. In conclusion, the results indicate that FT-Raman spectroscopy might be a useful tool for rapid assessment of nano particle biological interactions. 相似文献
6.
Jacques H. Van Boom Otto Dahl John E. Marugg John Nielsen 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract Alkyl bisaminophosphorodiamidites1 (1) has been shown to be versatile reagents for in situ preparation of d-nucleoside-3-phosphoramidites2,3,4 (2.) 相似文献
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