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101.
102.
Kinetics of Lifetime Changes in Bimetallic Nanocatalysts Revealed by Quick X‐ray Absorption Spectroscopy
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![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Matthias Filez Dr. Hilde Poelman Dr. Evgeniy A. Redekop Dr. Vladimir V. Galvita Dr. Konstantinos Alexopoulos Dr. Maria Meledina Dr. Ranjith K. Ramachandran Dr. Jolien Dendooven Prof. Christophe Detavernier Prof. Gustaaf Van Tendeloo Dr. Olga V. Safonova Dr. Maarten Nachtegaal Prof. Bert M. Weckhuysen Prof. Guy B. Marin 《Angewandte Chemie (International ed. in English)》2018,57(38):12430-12434
103.
Cyclization of γ-amino-α-bromocarboxylic esters resulted in an efficient synthesis of new 3,3-dimethoxyazetidine-2-carboxylates, that is, methyl N-t-butyl-3,3-dimethoxyazetidine-2-carboxylic ester and 3,3-dimethoxyazetidine-2-carboxylic acid, or 3-bromo-4,4-dimethoxypyrrolidin-2-ones, depending on the substituent at nitrogen. Reduction of the 3,3-dimethoxyazetidine-2-carboxylates gave the corresponding 3,3-dimethoxy-2-(hydroxymethyl)azetidines. These novel cyclic amino acid derivatives, available on multigram scale, have a suitably protected carbonyl function at the 3-position, which enables further functionalization. 相似文献
104.
A.F. Maarten Altelaar Ioana M. Taban Liam A. McDonnell Peter D.E.M. Verhaert Robert P.J. de Lange Roger A.H. Adan Wolter J. Mooi Ron M.A. Heeren Sander R. Piersma 《International journal of mass spectrometry》2007,260(2-3):203
Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) has been used to determine peptide distributions directly from rat, mouse and human pituitary tissue sections. Since these organs are small (102–103 μm) the spatial resolution of IMS is a key issue in molecular imaging of pituitary tissue sections. Here we show that high-resolution IMS allows localization of neuropeptide distributions within different cell clusters of a single organ of a pituitary tissue section. The sample preparation protocol does not result in analyte redistribution and is therefore applicable to IMS experiments at cellular length scales. The stigmatic imaging mass spectrometer used in this study produces selected-ion-count images with pixel sizes of 500 nm and a resolving power of 4 μm, yielding superior spatial detail compared to images obtained in microprobe imaging experiments. Furthermore, we show that with imaging mass spectrometry a distinction can be made between different mammalian tissue sections based on differences in the amino acid sequence of neuropeptides with the same function. This example demonstrates the power of IMS for label-free molecular imaging at relevant biological length scales. 相似文献
105.
106.
107.
Synthesis of poly(2‐oxazoline)s with side chain methyl ester functionalities: Detailed understanding of living copolymerization behavior of methyl ester containing monomers with 2‐alkyl‐2‐oxazolines
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Maarten Vergaelen Bryn D. Monnery Saron Catak Jan C. M. van Hest Veronique Van Speybroeck Richard Hoogenboom 《Journal of polymer science. Part A, Polymer chemistry》2015,53(22):2649-2661
Poly(2‐oxazoline)s with methyl ester functionalized side chains are interesting as they can undergo a direct amidation reaction or can be hydrolyzed to the carboxylic acid, making them versatile functional polymers for conjugation. In this work, detailed studies on the homo‐ and copolymerization kinetics of two methyl ester functionalized 2‐oxazoline monomers with 2‐methyl‐2‐oxazoline, 2‐ethyl‐2‐oxazoline, and 2‐n‐propyl‐2‐oxazoline are reported. The homopolymerization of the methyl ester functionalized monomers is found to be faster compared to the alkyl monomers, while copolymerization unexpectedly reveals that the methyl ester containing monomers significantly accelerate the polymerization. A computational study confirms that methyl ester groups increase the electrophilicity of the living chain end, even if they are not directly attached to the terminal residue. Moreover, the electrophilicity of the living chain end is found to be more important than the nucleophilicity of the monomer in determining the rate of propagation. However, the monomer nucleophilicity can be correlated with the different rates of incorporation when two monomers compete for the same chain end, that is, in copolymerizations. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2649–2661 相似文献
108.
Methodological challenges of optical tweezers‐based X‐ray fluorescence imaging of biological model organisms at synchrotron facilities
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Eva Vergucht Toon Brans Filip Beunis Jan Garrevoet Stephen Bauters Maarten De Rijcke David Deruytter Colin Janssen Christian Riekel Manfred Burghammer Laszlo Vincze 《Journal of synchrotron radiation》2015,22(4):1096-1105
Recently, a radically new synchrotron radiation‐based elemental imaging approach for the analysis of biological model organisms and single cells in their natural in vivo state was introduced. The methodology combines optical tweezers (OT) technology for non‐contact laser‐based sample manipulation with synchrotron radiation confocal X‐ray fluorescence (XRF) microimaging for the first time at ESRF‐ID13. The optical manipulation possibilities and limitations of biological model organisms, the OT setup developments for XRF imaging and the confocal XRF‐related challenges are reported. In general, the applicability of the OT‐based setup is extended with the aim of introducing the OT XRF methodology in all research fields where highly sensitive in vivo multi‐elemental analysis is of relevance at the (sub)micrometre spatial resolution level. 相似文献
109.
Chen K Lynen F De Beer M Hitzel L Ferguson P Hanna-Brown M Sandra P 《Journal of chromatography. A》2010,1217(46):7222-7230
Stationary phase optimized selectivity liquid chromatography (SOSLC) is a promising technique to optimize the selectivity of a given separation by using a combination of different stationary phases. Previous work has shown that SOSLC offers excellent possibilities for method development, especially after the recent modification towards linear gradient SOSLC. The present work is aimed at developing and extending the SOSLC approach towards selectivity optimization and method development for green chromatography. Contrary to current LC practices, a green mobile phase (water/ethanol/formic acid) is hereby preselected and the composition of the stationary phase is optimized under a given gradient profile to obtain baseline resolution of all target solutes in the shortest possible analysis time. With the algorithm adapted to the high viscosity property of ethanol, the principle is illustrated with a fast, full baseline resolution for a randomly selected mixture composed of sulphonamides, xanthine alkaloids and steroids. 相似文献
110.
We introduce the generic central character of an irreducible discrete series representation of an affine Hecke algebra. Using this invariant we give a new classification
of the irreducible discrete series characters for all abstract affine Hecke algebras (except for the types En(1){E_{n}^{(1)}} , n=6, 7, 8) with arbitrary positive parameters and we prove an explicit product formula for their formal degrees (in all cases). 相似文献