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排序方式: 共有310条查询结果,搜索用时 15 毫秒
71.
Carina Vidovič Dr. Lydia M. Peschel Michael Buchsteiner Prof. Dr. Ferdinand Belaj Prof. Dr. Nadia C. Mösch-Zanetti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(63):14267-14272
Bioinspired complexes employing the ligands 6-tert-butylpyridazine-3-thione (SPn) and pyridine-2-thione (SPy) were synthesized and fully characterized to mimic the tungstoenzyme acetylene hydratase (AH). The complexes [W(CO)(C2H2)(CHCH-SPy)(SPy)] ( 4 ) and [W(CO)(C2H2)(CHCH-SPn)(SPn)] ( 5 ) were formed by intramolecular nucleophilic attack of the nitrogen donors of the ligand on the coordinated C2H2 molecule. Labelling experiments using C2D2 with the SPy system revealed the insertion reaction proceeding via a bis-acetylene intermediate. The starting complex [W(CO)(C2H2)(SPy)2] ( 6 ) for these studies was accessed by the new acetylene precursor mixture [W(CO)(C2H2)n(MeCN)3−nBr2] (n=1 and 2; 7 ). All complexes represent rare examples in the field of W−C2H2 chemistry with 4 and 5 being the first of their kind. In the ongoing debate on the enzymatic mechanism, the findings support activation of acetylene by the tungsten center. 相似文献
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Silvère André Lydia Saint Cristau Sabine Gaillard Olivier Devos Éric Calvosa Ludovic Duponchel 《Analytica chimica acta》2015
The Food and Drug Administration's (FDA) process analytical technology (PAT) framework has been initiated to encourage drug manufacturers to develop innovative techniques in order to better understand their processes and institute high level quality control which allows action at any point in the manufacturing process. While Raman spectroscopy and chemometrics have been successfully used to predict concentration of conventional metabolites in cell cultures, it is really not the case for active substances. Thus, we propose, for the first time, an in-line and real-time prediction of recombinant antibody titer using an immersion probe link to a spectrometer without the tacking of samples. A good robustness of the method is observed on different culture batches and the contamination risk is drastically reduced which is an important issue in biotechnology manufacturing processes. 相似文献
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Cotinine levels in biological fluids are a reliable indicator of the presence of nicotine. In this paper, a simple and sensitive high-performance liquid chromatography (HPLC) procedure for the determination of cotinine in urine following liquid-liquid extraction with dichloromethane in an alkaline medium is described. Calibration curves show linearity over the 50 to 3000 ng/mL range with low intra- and interday variability as well as good selectivity and specificity. No solid-phase extraction is performed because the liquid dichloromethane extraction step yields excellent results. This method is a good alternative for routine analysis of urinary cotinine in laboratories where gas chromatography or HPLC-mass spectrometry is not available. 相似文献
80.
Andrea C. Bruttomesso Javier Eiras Javier A. Ramírez Lydia R. Galagovsky 《Tetrahedron letters》2009,50(28):4022-4024
In this Letter we report that the Ugi reaction/cyclization sequence on a steroidal 17-carboxaldehyde leads to novel steroidal 2,5-diketopiperazines with a noteworthy stereoselectivity. A wide variety in the substitution pattern in the heterocyclic moiety was easily achieved by changing the components in the Ugi reaction. 相似文献