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Lutz Kummer Chia-Wen Hsu Onur Dagliyan Christopher MacNevin Melanie Kaufholz Bastian Zimmermann Nikolay V. Dokholyan Klaus M. Hahn Andreas Plückthun 《Chemistry & biology》2013,20(6):847-856
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Stella A. Verkhnyatskaya Alex H. de Vries Elmatine Douma-de Vries Renze J. L. Sneep Dr. Marthe T. C. Walvoort 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6722-6727
A straightforward glycosylation method is described to regio- and stereoselectively introduce two α-l -fucose moieties directly to the secondary rim of β-cyclodextrin. Using NMR and MS fragmentation studies, the nonasaccharide structure was determined, which was also visualized using molecular dynamics simulations. The reported glycosylation method proved to be robust on gram-scale, and may be generally applied to directly glycosylate β-cyclodextrins to make well-defined multivalent glycoclusters. 相似文献
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Gallai’s path decomposition conjecture states that the edges of any connected graph on vertices can be decomposed into at most paths. We confirm that conjecture for all graphs with maximum degree at most five. 相似文献
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Niels Weidmann Marthe Ketels Prof. Dr. Paul Knochel 《Angewandte Chemie (International ed. in English)》2018,57(33):10748-10751
The first sodiations of (hetero)arenes in continuous flow using NaDA (sodium diisopropylamide) in Me2EtN are reported. This flow procedure enables sodiation of functionalized arenes and heteroarenes that decompose under batch‐sodiation conditions. The resulting sodiated (hetero)arenes react instantly with various electrophiles, such as ketones, aldehydes, isocyanates, alkyl bromides, and disulfides, affording polyfunctionalized (hetero)arenes in high yields. Scale‐up is possible without further optimization. 相似文献
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The determination of a pipe bore from the measured reflection function is a technique that has reached a certain maturity. However, the measurement of the reflection function in the time domain (pulse reflectometry) requires equipment that is rather difficult to operate. On the other hand, the techniques for measuring the input impedance have reached an unquestionable maturity with respect to measurement setup and to calibration. It is thus likely that impedance measurements might be able to give the same information. By doing simulations, it is first shown that the reflection function deduced from the input impedance gives access to the bore with a precision comparable with that obtained with pulse reflectometry. It is then shown that the accuracy obtained with measurements is of the same order as that obtained from simulations. The technique is then used for the dimensional inspection of bassoon crooks. 相似文献
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Lars Erik Eng Eibak Marthe Petrine Parmer Knut Einar Rasmussen Stig Pedersen-Bjergaard Astrid Gjelstad 《Analytical and bioanalytical chemistry》2014,406(2):431-440
This paper describes the concept of parallel electromembrane extraction (Pa-EME) with flat membranes in a multiwell format for the first time. The setup is based on a multiwell plate and provided simultaneous and selective isolation, cleanup, and enrichment of several human plasma samples as well as LC-MS-compatible extracts within 8 min of extraction. Undiluted human plasma samples spiked with four antidepressant drugs were added to separate wells in the donor plate. Subsequently, the samples were extracted with Pa-EME. The four drugs migrated electrokinetically from undiluted human plasma through a flat polypropylene membrane impregnated with 2-nitrophenyl octyl ether, and were isolated into formic acid. Extraction time, extraction voltage, agitation rate, sample volume, and acceptor solution volume were all optimized with an experimental design. The optimal conditions were as follows: The agitation rate was 1,040 rpm, and an extraction voltage of 200 V was applied. The sample volume and acceptor solution volume was 240 and 70 μL, respectively. The extraction was continued for 8 min. Eventually, the extracts were analyzed by LC-MS/MS. The combination of Pa-EME with LC-MS/MS provided quantitation limits below the therapeutic level and reported relative standard deviations in the range 5–13 %. Linear calibration curves were obtained for all analytes, and the correlation coefficients were above 0.9974 in the range 1–400 ng mL?1. The drug concentrations from two subjects treated with quetiapine and sertraline were successfully determined with Pa-EME combined with LC-MS/MS. Post-column infusion experiments demonstrated that Pa-EME provided extracts free from interfering matrix components. 相似文献
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Walvoort MT Moggré GJ Lodder G Overkleeft HS Codée JD van der Marel GA 《The Journal of organic chemistry》2011,76(18):7301-7315
With the aim to find an efficient synthetic procedure for the construction of 2,3-diamino-2,3-dideoxy-β-D-mannuronic acids, we evaluated three mannosyl donors: (S)-phenyl 4,6-di-O-acetyl-2,3-diazido mannopyranoside, (S)-phenyl 2,3-diazido-4,6-O-benzylidene mannopyranoside, and (S)-phenyl 2,3-diazido mannopyranosyl methyl uronate. The first two mannosylating agents are rather unselective or slightly α-selective in their condensation with three different acceptors. The mannuronic acid donor on the other hand reliably provides the desired β-mannosidic linkage. A mechanistic rationale is put forward to account for the different behavior of the three donor types. Suitably protected 2,3-diazido mannuronic acids were employed to construct the all-cis-linked tetrasaccharide repeating unit of the capsular polysaccharide of Bacillus stearothermophilus , featuring two 2,3-diacetamido-2,3-dideoxy-β-D-mannuronic acids. 相似文献
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Olusesan Ojo Micheal H.K. Kengne Marthe C. Fotsing Edwin M. Mmutlane Derek T. Ndinteh 《Arabian Journal of Chemistry》2021,14(7):103213
Vitellaria paradoxa Gaertn. is a multipurpose medicinal plant of the family Sapotaceae, and it has been widely used usually in the clinical traditional medicine as remedy for a wide range of diseases for several decades. In addition, the plant has also found applications in confectionery, cosmetics and soaps, and pharmaceuticals both locally and internationally. V. paradoxa, which has been identified with >150 phytoconstituents, is rich in oleanane-type triterpene acids and glycosides, such as paradoxosides A-E, tieghemelin A, parkiosides A-C, bassic acid, as well as flavonoids such as quercetin and catechin-type compounds. The extracts and the active constituents of V. paradoxa have been investigated for various pharmacological activities, including but not limited to anticancer, melanogenesis-inhibitory, antibacterial, anti-diabetic, antioxidant, anti-inflammatory, anti-diarrhoeal, and antifungal activities. Additionally, V. paradoxa has also been utilized in nanoparticles (NPs) synthesis. These NPs among other things have shown significant antinociceptive and antiedematogenic activities as well as environmental friendly adsorptive properties for the removal of pollutants from pharmaceutical effluents. Overall, this review comprehensively examines the traditional uses, phytochemistry, pharmacology, toxicology, clinical studies, and nanoparticles synthesized from V. paradoxa and their applications. 相似文献