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51.
52.
Characterization and kinetic performance of 2.1 × 100 mm production columns packed with new 1.6 μm superficially porous particles 下载免费PDF全文
Fabrice Gritti Stephen Shiner Jacob N. Fairchild Georges Guiochon 《Journal of separation science》2014,37(23):3418-3425
The overall kinetic performance of three production columns (2.1 mm × 100 mm format) packed with 1.6 μm superficially porous CORTECS‐C18+ particles was assessed on a low‐dispersive I‐class ACQUITY instrument. The values of their minimum intrinsic reduced plate heights (hmin = 1.42, 1.57, and 1.75) were measured at room temperature (295 K) for a small molecule (naphthalene) with an acetonitrile/water eluent mixture (75:25, v/v). These narrow‐bore columns provide an average intrinsic efficiency of 395 000 plates per meter. The gradient separation of 14 small molecules shows that these columns have a peak capacity about 25% larger than similar ones packed with fully porous BEH‐C18 particles (1.7 μm) or shorter (50 mm) columns packed with smaller core–shell particles (1.3 μm) operated under very high pressure (>1000 bar) for steep gradient elution (analysis time 80 s). In contrast, because their permeabilities are lower than those of columns packed with larger core–shell particles, their peak capacities are 25% smaller than those of narrow‐bore columns packed with standard 2.7 μm core–shell particles. 相似文献
53.
Fabrice Ofridam Noureddine Lebaz milie Gagnire Denis Mangin Abdelhamid Elaissari 《先进技术聚合物》2021,32(1):379-390
Precipitation or coprecipitation of polyelectrolytes has been largely investigated. However, the precipitation of polyelectrolytes via addition of charged and non‐charged surfactants has not been systematically studied and reported. Consequently, the aim of this work is to investigate the effect of different surfactants (anionic, cationic, non‐charged and zwitterionic) on the precipitation of cationic and anionic polymethylmethacrylate polymers (Eudragit). The surfactants effect has been investigated as a function of their concentration. Special attention has been dedicated to the CMC range and to the colloidal characterization of the formed dispersions. Moreover, the effect of salt (NaCl) and pH was also addressed. It is pointed out that non‐ionic and zwitterionic surfactants do not interact with charged Eudragit E100 and L100. For oppositely charged Eudragit E100/SDS and Eudragit L100/CTAB, precipitation occurs, and the obtained dispersions have been characterized in terms of particle size distribution and zeta potential. It was established that the binding of SDS molecules to Eudragit E100 polymer chains is made through the negative charges of the surfactant heads under the CMC value whereas binding of CTAB to Eudragit L100 chains is made at a CTAB concentration 5 times above its CMC. For Eudragit E100/SDS system, a more acidic medium induces aggregation. A same result was observed for the Eudragit L100/CTAB at a more basic pH. Moreover, it was observed that increasing salt concentration (higher than 100 mM) led to aggregation as generally observed for polycations/anionic surfactant systems. 相似文献
54.
Bruno Oyallon Marie Brachet-Botineau Cdric Log Thomas Robert Stphane Bach Sajida Ibrahim William Raoul Ccile Croix Pascal Berthelot Jean Guillon Noël Pinaud Fabrice Gouilleux Marie-Claude Viaud-Massuard Caroline Denevault-Sabourin 《Molecules (Basel, Switzerland)》2021,26(4)
Proviral integration site for Moloney murine leukemia virus (Pim)-1/2 kinase overexpression has been identified in a variety of hematologic (e.g., multiple myeloma or acute myeloid leukemia (AML)) and solid (e.g., colorectal carcinoma) tumors, playing a key role in cancer progression, metastasis, and drug resistance, and is linked to poor prognosis. These kinases are thus considered interesting targets in oncology. We report herein the design, synthesis, structure–activity relationships (SAR) and in vitro evaluations of new quinoxaline derivatives, acting as dual Pim1/2 inhibitors. Two lead compounds (5c and 5e) were then identified, as potent submicromolar Pim-1 and Pim-2 inhibitors. These molecules were also able to inhibit the growth of the two human cell lines, MV4-11 (AML) and HCT-116 (colorectal carcinoma), expressing high endogenous levels of Pim-1/2 kinases. 相似文献
55.
Gerbier F 《Physical review letters》2007,99(12):120405
We discuss the finite temperature properties of ultracold bosons in optical lattices in the presence of an additional, smoothly varying potential, as in current experiments. Three regimes emerge in the phase diagram: a low-temperature Mott regime similar to the zero-temperature quantum phase, an intermediate regime where Mott insulator features persist, but where superfluidity is absent, and a thermal regime where features of the Mott insulator state have disappeared. We obtain the thermodynamic functions of the Mott phase in the latter cases. The results are used to estimate the temperatures achieved by adiabatic loading in current experiments. We point out the crucial role of the trapping potential in determining the final temperature, and suggest a scheme for further cooling by adiabatic decompression. 相似文献
56.
An Efficient RuII–RhIII–RuII Polypyridyl Photocatalyst for Visible‐Light‐Driven Hydrogen Production in Aqueous Solution 下载免费PDF全文
Dr. Thibaut Stoll Dr. Marcello Gennari Dr. Jérôme Fortage Dr. Carmen E. Castillo Dr. Mateusz Rebarz Dr. Michel Sliwa Dr. Olivier Poizat Dr. Fabrice Odobel Dr. Alain Deronzier Dr. Marie‐Noëlle Collomb 《Angewandte Chemie (International ed. in English)》2014,53(6):1654-1658
The development of multicomponent molecular systems for the photocatalytic reduction of water to hydrogen has experienced considerable growth since the end of the 1970s. Recently, with the aim of improving the efficiency of the catalysis, single‐component photocatalysts have been developed in which the photosensitizer is chemically coupled to the hydrogen‐evolving catalyst in the same molecule through a bridging ligand. Until now, none of these photocatalysts has operated efficiently in pure aqueous solution: a highly desirable medium for energy‐conversion applications. Herein, we introduce a new ruthenium–rhodium polypyridyl complex as the first efficient homogeneous photocatalyst for H2 production in water with turnover numbers of several hundred. This study also demonstrates unambiguously that the catalytic performance of such systems linked through a nonconjugated bridge is significantly improved as compared to that of a mixture of the separate components. 相似文献
57.
Unraveling the Crystal Structure of Lanthanide–Murexide Complexes: Use of an Ancient Complexometry Indicator as a Near‐Infrared‐Emitting Single‐Ion Magnet 下载免费PDF全文
Xiaohui Yi Dr. Kevin Bernot Vincent Le Corre Dr. Guillaume Calvez Dr. Fabrice Pointillart Dr. Olivier Cador Dr. Boris Le Guennic Julie Jung Dr. Olivier Maury Dr. Virginie Placide Dr. Yannick Guyot Dr. Thierry Roisnel Dr. Carole Daiguebonne Prof. Olivier Guillou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1569-1576
Herein, we provide some structural evidence of the complexation color‐change of murexide solutions in presence of lanthanide, which has been used for decades in complexometric studies. For Ln=Sm to Lu and Y, the compounds crystallize as monomeric [Ln(Murex)3] ? 11 H2O with an N3O6 tricapped square‐antiprism environment, which are stable up to 250 °C. Single‐ion magnet (SIM) behavior is then observed on the YbIII derivative in an original nine‐coordinated environment. In‐field slow relaxation (Δ=(15.6±1) K; τ0=2.73×10?6 s) is observed with a very narrow distribution of the relaxation time (αmax=0.09). Magnetic and photophysical properties can be correlated. On one hand the analysis of NIR emission spectrum permits to have access to crystal field parameters and to compare them with those extracted from dc measurements. On the other hand, magnetic measurements permit to identify the nature of the M J states involved in the 2F5/2→2F7/2 luminescence spectrum. The gap between the low‐lying states is in agreement with the energy barrier obtained from magnetic slow‐relaxation measurement. 相似文献
58.
On the Synthesis,Characterization and Reactivity of N‐Heteroaryl–Boryl Radicals,a New Radical Class Based on Five‐Membered Ring Ligands 下载免费PDF全文
Dr. Mohamad‐Ali Tehfe Dr. Stéphane Schweizer Dr. Anne‐Caroline Chany Dr. Cédric Ysacco Dr. Jean‐Louis Clément Dr. Didier Gigmes Dr. Fabrice Morlet‐Savary Prof. Jean‐Pierre Fouassier Dr. Markus Neuburger Dr. Théophile Tschamber Dr. Nicolas Blanchard Prof. Jacques Lalevée 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):5054-5063
The synthesis and physical characterization of a new class of N‐heterocycle–boryl radicals is presented, based on five membered ring ligands with a N(sp2) complexation site. These pyrazole–boranes and pyrazaboles exhibit a low bond dissociation energy (BDE; B?H) and accordingly excellent hydrogen transfer properties. Most importantly, a high modulation of the BDE(B?H) by the fine tuning of the N‐heterocyclic ligand was obtained in this series and could be correlated with the spin density on the boron atom of the corresponding radical. The reactivity of the latter for small molecule chemistry has been studied through the determination of several reaction rate constants corresponding to addition to alkenes and alkynes, addition to O2, oxidation by iodonium salts and halogen abstraction from alkyl halides. Two selected applications of N‐heterocycle–boryl radicals are also proposed herein, for radical polymerization and for radical dehalogenation reactions. 相似文献
59.
Back Cover: Assessment of DNA Binding to Human Rad51 Protein by using Quartz Crystal Microbalance and Atomic Force Microscopy: Effects of ADP and BRC4‐28 Peptide Inhibitor (ChemPhysChem 17/2014) 下载免费PDF全文
60.
Xavier Cattoën Achraf Noureddine Jonas Croissant Nirmalya Moitra Kristýna Bürglová Jana Hodačová Olivia de los Cobos Martine Lejeune Fabrice Rossignol Delphine Toulemon Sylvie Bégin-Colin Benoît P. Pichon Laurence Raehm Jean-Olivier Durand Michel Wong Chi Man 《Journal of Sol-Gel Science and Technology》2014,70(2):245-253
The combination of the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction with sol–gel processing enables the versatile preparation of sol–gel materials under different shapes with targeted functionalities through a diversity-oriented approach. In this account, the development of the CuAAC reaction under anhydrous conditions for the synthesis of sol–gel precursors and for the assembling of magnetic nanoparticles on self-assembled monolayers is related, as well as the use of the classical CuAAC methodologies for the functionalization of mesoporous silica nanoparticles and microdots arrays. Coupling CuAAC and Sol–Gel will result in simplified preparations of multifunctional materials with controlled morphologies. 相似文献