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131.
Frontiers of Physics - This article presents a review of our present understanding of the spin structure of the unpolarized hadron. Particular attention is paid to the quark sector at leading... 相似文献
132.
Abdellatif Moudafi 《Numerical Functional Analysis & Optimization》2013,34(5-6):582-590
We study the convergence of a variable version of the Krasnoselski–Mann algorithm applied to a primal dual fixed point problem. The link with Spingarn's partial inverse method is made, and an application to feasibility problems and mathematical programming is also proposed. 相似文献
133.
Chouai A Wicke SE Turro C Bacsa J Dunbar KR Wang D Thummel RP 《Inorganic chemistry》2005,44(17):5996-6003
Four complexes of the ligand 1,12-diazaperylene (DAP) have been prepared, [Ru(bpy)n(DAP)(3-n)]2+ where n = 0-2 and [Ru(DAP)3]2+. The [Ru(DAP)3]2+ complex was characterized by X-ray analysis and was found to exhibit the expected propeller-like structure with significant intermolecular pi-stacking interactions. The three Ru(II) complexes showed self-consistent optoelectronic properties with similar ligand-centered pi-pi* absorptions in the range of 333-468 nm and MLCT bands associated with the DAP which increased in intensity and decreased in energy as the number of DAP ligands varied from 1 to 3. Hypochromicity and viscosity changes were observed that were consistent with DAP intercalation into DNA, and binding constants were measured in the range of 1.4-1.6 x 10(6) M(-1) for the mixed ligand complexes. Furthermore, the complex [Ru(bpy)2(DAP)]2+ was found to photocleave plasmid DNA upon irradiation with visible light. 相似文献
134.
Dr. Abdellatif Tikad Huixiao Fu Dr. Charlotte M. Sevrain Prof. Sophie Laurent Dr. Jean‐François Nierengarten Prof. Stéphane P. Vincent 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13147-13155
The synthesis of unprecedented multimeric Kdo glycoclusters based on fullerene and calix[4]arene central scaffolds is reported. The compounds were used to study the mechanism and scope of multivalent glycosyltransferase inhibition. Multimeric mannosides based on porphyrin and pillar[5]arenes were also generated in a controlled manner. Twelve glycoclusters and their monomeric ligands were thus assayed against heptosyltransferase WaaC, which is an important bacterial glycosyltransferase that is involved in lipopolysaccharide biosynthesis. It was first found that all the multimers interact solely with the acceptor binding site of the enzyme even when the multimeric ligands mimic the heptose donor. Second, the novel Kdo glycofullerenes displayed very potent inhibition (Ki=0.14 μm for the best inhibitor); an inhibition level rarely observed with glycosyltransferases. Although the observed “multivalent effects” (i.e., the enhancement of affinity of a ligand when presented in a multimeric fashion) were in general modest, a dramatic effect of the central scaffold on the inhibition level was evidenced: the fullerene and the porphyrin scaffolds being by far superior to the calix‐ and pillar‐arenes. We could also show, by dynamic light scattering analysis, that the best inhibitor had the propensity to form aggregates with the heptosyltransferase. This aggregative property may contribute to the global multivalent enzyme inhibition, but probably do not constitute the main origin of inhibition. 相似文献
135.
Joakim Delaux Prof. Carmen Ortiz Mellet Christine Canaff Dr. Elodie Fourré Dr. Cédric Gaillard Dr. Abdellatif Barakat Prof. José M. García Fernández Dr. Jean‐Michel Tatibouët Dr. François Jérôme 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(46):16522-16530
We have investigated the effect of non‐thermal atmospheric plasma (NTAP) on the structure of microcrystalline cellulose. In particular, by means of different characterization methods, we demonstrate that NTAP promotes the partial cleavage of the β‐1,4 glycosidic bond of cellulose leading to the release of short‐chain cellodextrins that are reassembled in situ, preferentially at the C6 position, to form branched glucans with either a glucosyl or anhydroglucosyl terminal residue. The ramification of cellulosic chain induced by NTAP yields branched glucans that are soluble in DMSO or in water, thus opening a straightforward access to processable glucans from cellulose. Importantly, the absence of solvent and catalyst considerably facilitates downstream processing as compared to (bio)catalytic processes which typically occur in diluted conditions. 相似文献
136.
137.
Brahmi Y Katir N Hameau A Essoumhi A Essassi el M Caminade AM Bousmina M Majoral JP El Kadib A 《Chemical communications (Cambridge, England)》2011,47(30):8626-8628
Controlled titanium alkoxide mineralization in the presence of phosphonated, dendrimeric nano-building blocks provides a new family of hierarchically porous dendrimer-bridged titanium dioxide materials. 相似文献
138.
An efficient and general low-cost method is described to obtain chiral Nβ-Boc protected α-Nα-hydrazino diester building-blocks (orthogonally and non-orthogonally protected diesters) on multi-gram scale (30 mmol) using two successive SN2 reactions. This method is also convenient for the introduction of both polar and nonpolar side chains on the Nα-atom and represents an inexpensive and attractive alternative compared to the more expensive method using commercial oxaziridine reagents for N-amination of α-amino acids. 相似文献
139.
Abdellatif Boureghda 《Journal of Difference Equations and Applications》2013,19(9):1443-1455
A modified numerical method was used by authors for solving 1D Stefan problem. In this paper a modified method is proposed with difference formulae and different methods of calculating the variable time step, which are deduced from Taylor series expansions of different conditions at the boundary. Also an extrapolation formula for the solution at the first point at the right of the computational domain is proposed. The numerical results are compared with those obtained from other methods. 相似文献
140.
Abdellatif Moudafi 《Numerical Functional Analysis & Optimization》2013,34(1):39-47
This article is concerned with a generalization of the hybrid steepest descent method from variational inequalities to the multivalued case. This will be reached by replacing the multivalued operator by its Yosida approximate, which is always Lipschitz continuous. It is worth mentioning that the hybrid steepest descent method is an algorithmic solution to variational inequality problems over the fixed point set of certain nonexpansive mappings and has remarkable applicability to the constrained nonlinear inverse problems like image recovery and MIMO communication systems (see, e.g., [9, 10]). 相似文献