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171.
The behaviour of bovine serum albumin in cyclic voltammetry and differential-pulse adsorptive stripping voltammetry is described. Under the optimized conditions, with an accumulation potential of +0.15 V (vs. Ag/AgCl) and accumulation times of 50 s or 120 s, linear calibration graphs were obtained for 1.0–4.0×10?8 M BSA and 0.2–1.5×10?8 M BSA, respectively. 相似文献
172.
Janine Cossy Haja Rakotoarisoa Philippe Kahn Jean-Roger Desmurs 《Tetrahedron letters》1998,39(52):3240-9674
The synthesis of functionalized 2,2-disubstituted 2H-1-benzopyrans was achieved by condensing 2,3,5-trimethylhydroquinone (TMHQ) with ,β-unsaturated aldehydes or ,β-unsaturated acetals under acidic conditions. 相似文献
173.
Anthony Fratiello Vicki Kubo-Anderson Soheil Azimi Thomas Flores Eric Marinez Dennis Matejka Richard Perrigan Michael Vigil 《Journal of solution chemistry》1990,19(8):811-829
A coordination study of Lu(III) has been carried out for the nitrate and perchlorate salts in aqueous mixtures of acetone-d6 and Freon-12 by1H,15N and35Cl NMR spectroscopy. At temperatures lower than –90°C, proton and ligand exchange are slow enough to permit the direct observation of1H resonance signals for coordinated and free water molecules, leading to an accurate measure of the Lu(III) hydration number. In perchlorate solution, in the absence of inner-shell ion-pairing, Lu(III) exhibits a maximum coordination number of six over the allowable concentration range of study, contrasting markedly with the report of values of six to nine or greater as determined by a similar NMR method. The absence of contact ion-pairing was confirmed by35Cl NMR chemical shift and linewidth measurements. Extensive ion-pairing was observed in the nitrate solutions as reflected by the lower Lu(III) hydration numbers of two to three in these systems, the observation of two coordinated water signals, and15N NMR signals for two complexes. The1H and15N NMR spectra and the hydration number could be accounted for by the presence of (H2O)4Lu(NO3)2+ and (H2O)2Lu(NO3)
2
1+
. 相似文献
174.
Benjamin Ruiz Philippe Sistat Patrice Huguet Gérald Pourcelly Monica Araya-Farias Laurent Bazinet 《Journal of membrane science》2007
Electrodialysis (ED) is a membrane process used on a large scale. However, one of the common problems is fouling of ion-exchange membranes stacked in the cell. The use of pulsed power, consisting in applying a constant current density during a fixed time of application (Ton) followed by a pause duration (Toff), was demonstrated recently as an effective fouling mitigation method for electrodialysis. Up until now, no work has investigated the potential of electrodialysis using pulsed electric field on protein fouling. The aim of the present work was to study the influence of pulsed electric field (PEF) with a low frequency square shaped periodic signal (Ton = 10 s–Toff = 10 s, Ton = 10 s–Toff = 40 s) in comparison with dc current during electrodialysis of a casein solution at different current densities (10, 20 and 30 mA/cm2) on membrane fouling. It appeared from these results that PEF, under certain conditions of pulse, would avoid fouling on anion-exchange membranes. For 10 s–40 s pulsed electric field conditions, no fouling was observed with any density, while for 10 s–10 s PEF conditions, fouling appeared only at current density over 10 mA/cm2. dc current, whatever the current density conditions, led to a fouling on the diluate side of the AEM. Furthermore, when fouling occurred, magnitude layer thickness and dry weight increased with the applied current density. The nature of the fouling was identified as 97% protein. The protein fouling would be due to the dissociation of water molecules and/or heat increase at the anion-exchange membrane interface. The relaxation time of the pulse would limit both phenomena on the membrane. 相似文献
175.
Nicolas P. Cheval Barbara Hoffmann Anna Dikova Fatih Sirindil Philippe Bertus Aurélien Blanc Jean-Marc Weibel Patrick Pale 《Tetrahedron》2018,74(50):7111-7119
Vinyl nosylates, readily obtained from β-dicarbonyl derivatives, could be efficiently engaged in Sonogashira cross-coupling reactions, either cocatalyzed by copper or silver salts. The para-nitrobenzenesulfonate (nosylate) group allows this coupling to be performed under very mild conditions (room temperature). These new leaving group and mild conditions could be applied to the synthesis of acetylenic coumarinyl derivatives and to the total synthesis of an acetylenic monoterpene natural product, named cleviolide. 相似文献
176.
177.
Philippe Rukimbira 《Journal of Geometry》2016,107(1):125-135
On a Riemannian manifold, any parallel form is preserved by the flow of any Killing vector field with constant magnitude. As a consequence, on a 2n+1-dimensional K-contact manifold, there are no nontrivial parallel forms except of degrees 0 and 2n+1. Flat contact metrics on 3-manifolds are characterized by reducible holonomy. 相似文献
178.
Dolorès Edmont Yvon Buisson Philippe Treillard Christophe Plisson Jacques Chenault 《合成通讯》2013,43(2):217-225
A high yielding N-amination of quinolones at low temperature via the use of O-mesitylenesulfonylhydroxylamine is reported. 相似文献
179.
Anne-Catherine Huet Monique Bienenmann-Ploum Ursula Vincent Philippe Delahaut 《Analytical and bioanalytical chemistry》2013,405(24):7733-7751
This article presents a review of the current trends in the analysis of coccidiostats in various matrices, focusing principally on screening and rapid methods. Coccidiosis is an infectious disease having a high negative impact on the animal industry. Drugs are therefore necessary to prevent and/or to combat this disease. However, it is also of crucial importance that these veterinary drugs do not enter the human food chain. European legislation has therefore established the boundaries for the use of coccidiosats and has also addressed the unavoidable problem of cross-contamination of the feed, mainly caused by the use of the same production lines. Consequently there is a need for analytical methods and/or analytical strategies for the monitoring and control of the residues of anticoccidials, both in feed and in the resulting matrices for human consumption. In the frame of the European collaborative project CONffIDENCE, such attempts to establish the required analytical tools were made, which required beforehand a review of the state of the art in this domain. Aiming at this objective, in this review we consider the most interesting publications since 2000. In essence, both a rapid approach with mainly immunoassays and chromatographic methods were developed. To date, the obstacle to routine use of the first approach has been its inability to detect more than two compounds simultaneously, but recent developments in flow cytometry have made it possible to detect six coccidiostats at once. On the other hand, an increasingly popular approach for detecting multiple coccidiostats simultaneously is liquid chromatography coupled with tandem mass spectrometry. There remains a need to adapt these analytical methods to legislative requirements. 相似文献
180.
Maxime Guitet Pinglu Zhang Filipa Marcelo Coralie Tugny Jesús Jimnez‐Barbero Olivier Buriez Christian Amatore Virginie Mouris‐Mansuy Jean‐Philippe Goddard Louis Fensterbank Yongmin Zhang Sylvain Roland Mickaël Mnand Matthieu Sollogoub 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2013,125(28):7354-7359