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61.
Dr. Julien Es Sayed Dr. Cédric Lorthioir Dr. Philippe Banet Prof. Patrick Perrin Dr. Nicolas Sanson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7108-7114
The combination of supramolecular chemistry and soft colloids as microgels represents an ambitious way to develop multi-versatile colloidal assemblies. Hereafter, terpyridine-functionalized poly(N-isopropylacrylamide) (PNiPAM) microgel building blocks are shown to undergo an assemble–freeze–disassemble process. The microgel assemblies, which are controlled by monitoring the attractive and repulsive potentials between the soft colloidal particles, are then frozen by forming inter-particle metal–terpyridine bis-complexes upon addition of the metallic cation (such as FeII, CoII). By oxidation of the metal–terpyridine bis-complex links, the aggregates open up, which is due to the complex dissociation releasing the connected particles in the form of single microgels. We extended our work to the development of 1D filaments and 2D membranes materials made of soft particles connected via supramolecular chemistry. 相似文献
62.
Dr. Julien Gasnot Clément Botella Dr. Sébastien Comesse Dr. Sami Lakhdar Dr. Carole Alayrac Prof. Annie-Claude Gaumont Prof. Vincent Dalla Dr. Catherine Taillier 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):11867-11871
Advances in the field of phosphorus chemistry are documented, by revealing the synthetic utility of previously underutilized quaternary phosphiranium salts (QPrS) as three-chain-atom electrophilic building blocks. Notably, control of their challenging C-centered electrophilicity is disclosed with an expedient synthesis of tertiary β-anilino phosphines as a proof-of-concept. 相似文献
63.
Ania Alik Chafiaa Bouguechtouli Manon Julien Wolfgang Bermel Rania Ghouil Sophie Zinn‐Justin Francois‐Xavier Theillet 《Angewandte Chemie (International ed. in English)》2020,59(26):10411-10415
Abundant phosphorylation events control the activity of nuclear proteins involved in gene regulation and DNA repair. These occur mostly on disordered regions of proteins, which often contain multiple phosphosites. Comprehensive and quantitative monitoring of phosphorylation reactions is theoretically achievable at a residue‐specific level using 1H‐15N NMR spectroscopy, but is often limited by low signal‐to‐noise at pH>7 and T>293 K. We have developed an improved 13Cα‐13CO correlation NMR experiment that works equally at any pH or temperature, that is, also under conditions at which kinases are active. This allows us to obtain atomic‐resolution information in physiological conditions down to 25 μm . We demonstrate the potential of this approach by monitoring phosphorylation reactions, in the presence of purified kinases or in cell extracts, on a range of previously problematic targets, namely Mdm2, BRCA2, and Oct4. 相似文献
64.
Julien Warnan Erwin Reisner 《Angewandte Chemie (International ed. in English)》2020,59(40):17344-17354
From the understanding of biological processes and metalloenzymes to the development of inorganic catalysts, electro‐ and photocatalytic systems for fuel generation have evolved considerably during the last decades. Recently, organic and hybrid organic systems have emerged to challenge the classical inorganic structures through their enormous chemical diversity and modularity that led earlier to their success in organic (opto)electronics. This Minireview describes recent advances in the design of synthetic organic architectures and promising strategies toward (solar) fuel synthesis, highlighting progress on materials from organic ligands and chromophores to conjugated polymers and covalent organic frameworks. 相似文献
65.
Gelatin‐Alginate Gels and Their Enzymatic Modifications: Controlling the Delivery of Small Molecules
Marie‐Cécile Klak Elodie Lefebvre Laure Rémy Rémy Agniel Julien Picard Sébastien Giraudier Véronique Larreta‐Garde 《Macromolecular bioscience》2013,13(6):687-695
The release of molecules entrapped within biogels is dictated by diffusion laws. Innovative biogel architectures are conceived and tested to control small molecule delivery from gelatin gels. The ionic interactions modulate the release of small molecules. Alginate is then added to gelatin gels and further hydrolyzed; the influence of viscosity is discussed. Next, various mixed gels are compared, such as a gelatin‐alginate IPN and the original architecture of an alginate gel entrapped in a gelatin gel with or without a polysaccharidase. The relative influence of ionic interactions and diffusional constraints on the delivery of small charged molecules is explored, and a solution for controlling diffusion is proposed for any situation.
66.
Michael G. Pfeffer Tanja Kowacs Dr. Maria Wächtler Dr. Julien Guthmuller Prof. Dr. Benjamin Dietzek Prof. Dr. Johannes G. Vos Prof. Dr. Sven Rau 《Angewandte Chemie (International ed. in English)》2015,54(22):6627-6631
A molecular photocatalyst consisting of a RuII photocenter, a tetrapyridophenazine bridging ligand, and a PtX2 (X=Cl or I) moiety as the catalytic center functions as a stable system for light‐driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy shows that the intramolecular photophysics are not affected by this change. Additionally, the general catalytic behavior, that is, instant hydrogen formation, a constant turnover frequency, and stability are maintained. Unlike as observed for the Pd analogue, the presence of excess halide does not affect the hydrogen generation capacity of the PMD. The highly improved catalytic efficiency is explained by an increased electron density at the Pt catalytic center, this is confirmed by DFT studies. 相似文献
67.
Marc Baboulin Jack Dongarra Serge Gratton Julien Langou 《Numerical Linear Algebra with Applications》2009,16(7):517-533
In this paper, we address the accuracy of the results for the overdetermined full rank linear least‐squares problem. We recall theoretical results obtained in (SIAM J. Matrix Anal. Appl. 2007; 29 (2):413–433) on conditioning of the least‐squares solution and the components of the solution when the matrix perturbations are measured in Frobenius or spectral norms. Then we define computable estimates for these condition numbers and we interpret them in terms of statistical quantities when the regression matrix and the right‐hand side are perturbed. In particular, we show that in the classical linear statistical model, the ratio of the variance of one component of the solution by the variance of the right‐hand side is exactly the condition number of this solution component when only perturbations on the right‐hand side are considered. We explain how to compute the variance–covariance matrix and the least‐squares conditioning using the libraries LAPACK (LAPACK Users' Guide (3rd edn). SIAM: Philadelphia, 1999) and ScaLAPACK (ScaLAPACK Users' Guide. SIAM: Philadelphia, 1997) and we give the corresponding computational cost. Finally we present a small historical numerical example that was used by Laplace (Théorie Analytique des Probabilités. Mme Ve Courcier, 1820; 497–530) for computing the mass of Jupiter and a physical application if the area of space geodesy. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
68.
Julien Nicolas Ségolène Brusseau Bernadette Charleux 《Journal of polymer science. Part A, Polymer chemistry》2010,48(1):34-47
Nitroxide‐mediated controlled/living free‐radical polymerization of methyl methacrylate initiated by the SG1‐based alkoxyamine BlocBuilder was successfully performed in bulk at 80–99 °C with the help of a very small amount of acrylonitrile (AN, 2.2–8.8 mol %) as a comonomer. Well‐defined PMMA‐rich P(MMA‐co‐AN) copolymers were prepared with the number‐average molar mass, Mn, in the 6.1–32 kg mol?1 range and polydispersity indexes as low as 1.24. Incorporation of AN in the copolymers was demonstrated by 1H and 13C NMR spectroscopy, and its effect on the chain thermal properties was evaluated by DSC and TGA analyses. Investigation of chain‐end functionalization by an alkoxyamine group was performed by means of 31P NMR spectroscopy and chain extensions from a P(MMA‐co‐AN)‐SG1 macroinitiator. It demonstrated the very high proportion of SG1‐terminated polymer chains, which opened the door to block copolymer synthesis with a high quality of control. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 34–47, 2010 相似文献
69.
Jean-Philippe Uzan George F. R. Ellis Julien Larena 《General Relativity and Gravitation》2011,43(1):191-205
In order to understand how locally static configurations around gravitationally bound bodies can be embedded in an expanding
universe, we investigate the solutions of general relativity describing a space–time whose spatial sections have the topology
of a 3-sphere with two identical masses at the poles. We show that Israel junction conditions imply that two spherically symmetric
static regions around the masses cannot be glued together. If one is interested in an exterior solution, this prevents the
geometry around the masses to be of the Schwarzschild type and leads to the introduction of a cosmological constant. The study
of the extension of the Kottler space–time shows that there exists a non-static solution consisting of two static regions
surrounding the masses that match a Kantowski–Sachs expanding region on the cosmological horizon. The comparison with a Swiss-Cheese
construction is also discussed. 相似文献
70.