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651.
Laurent Nyssen Marianne Fillet Etienne Cavalier Anne‐Catherine Servais 《Electrophoresis》2019,40(11):1550-1557
Parathyroid hormone (PTH) is a common clinical marker whose quantification relies on immunoassays, giving variable results as batch, brand, or target epitope changes. Sheathless CE‐ESI‐MS, combining CE resolution power and low‐flow ESI sensitivity, was applied to the analysis of PTH in its native conformation in the presence of related forms. Fused silica and neutral‐coated capillaries were investigated, as well as preconcentration methods such as transient isotachophoresis, field‐amplified sample injection (FASI), and electrokinetic supercharging (EKS). The method for the separation of PTH and its variants was first developed using fused‐silica capillary with UV detection. An acidic BGE was used to separate 1–84 PTH (full length), 7–84 PTH, and 1–34 PTH. Acetonitrile was added to the BGE to reduce peptide adsorption onto the capillary wall and transient isotachophoresis was used as analyte preconcentration method. The method was then transferred to a sheathless CE‐ESI‐MS instrument. When using a fused silica capillary, CE‐MS was limited to μg/mL levels. The use of a neutral coating combined with FASI or EKS allowed a significant increase in sensitivity. Under these conditions, 1–84 PTH, 7–84 PTH, and 1–34 PTH were detected at concentrations in the low ng/mL (FASI) or pg/mL (EKS) range. 相似文献
652.
Marianne Lankelma Astrid M. Olivares Prof. Dr. Bas de Bruin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(22):5658-5663
Radical cyclization via cobalt(III)-carbene radical intermediates is a powerful method for the synthesis of (hetero)cyclic structures. Building on the recently reported synthesis of five-membered N-heterocyclic pyrrolidines catalyzed by CoII porphyrins, the [Co(TPP)]-catalyzed formation of useful six-membered N-heterocyclic piperidines directly from linear aldehydes is presented herein. The piperidines were obtained in overall high yields, with linear alkenes being formed as side products in small amounts. A DFT study was performed to gain a deeper mechanistic understanding of the cobalt(II)-porphyrin-catalyzed formation of pyrrolidines, piperidines, and linear alkenes. The calculations showed that the alkenes are unlikely to be formed through an expected 1,2-hydrogen-atom transfer to the carbene carbon. Instead, the calculations were consistent with a pathway involving benzyl-radical formation followed by radical-rebound ring closure to form the piperidines. Competitive 1,5-hydrogen-atom transfer from the β-position to the benzyl radical explained the formation of linear alkenes as side products. 相似文献
653.
Marianne Akian Stéphane Gaubert Vassili Kolokoltsov 《Comptes Rendus Mathematique》2002,335(11):883-888
We consider equations of the form Bf=g, where B is a Galois connection between lattices of functions. This includes the case where B is the Fenchel transform, or more generally a Moreau conjugacy. We characterize the existence and uniqueness of a solution f in terms of generalized subdifferentials, which extends K. Zimmermann's covering theorem for max-plus linear equations. To cite this article: M. Akian et al., C. R. Acad. Sci. Paris, Ser. I 335 (2002) 883–888. 相似文献
654.
655.
Marianne Spittel 《Fresenius' Journal of Analytical Chemistry》1964,202(5):376
Ohne Zusammenfassung 相似文献
656.
Marianne Spittel 《Fresenius' Journal of Analytical Chemistry》1965,210(3):220
Ohne Zusammenfassung 相似文献
657.
Marianne Spittel 《Fresenius' Journal of Analytical Chemistry》1965,213(4):290
Ohne Zusammenfassung 相似文献
658.
659.
660.
Ursula Baumann P. Haas A. Niemann E. Müller Marianne Spittel und H. Garschagen 《Fresenius' Journal of Analytical Chemistry》1965,210(4):312-315
Ohne Zusammenfassung 相似文献