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801.
Self-assembly of CuI dimers, featuring a bridging phosphole ligand, and ditopic cyano-substituted chromophores affords nanosize supramolecular cationic rectangles. Due to the short Cu-Cu distance in the bimetallic clips, the coordinated chromophores are forced to participate in cofacial pi-pi interactions as evidenced by X-ray data. In addition, intermolecular pi-pi interactions in the solid state are observed leading to infinite columns of pi-stacked (para-phenylenevinylene)-based chromophores. 相似文献
802.
Erlacher MD Lang K Wotzel B Rieder R Micura R Polacek N 《Journal of the American Chemical Society》2006,128(13):4453-4459
The ribosomal peptidyl transferase center is a ribozyme catalyzing peptide bond synthesis in all organisms. We applied a novel modified nucleoside interference approach to identify functional groups at 9 universally conserved active site residues. Owing to their immediate proximity to the chemical center, the 23S rRNA nucleosides A2451, U2506 and U2585 were of particular interest. Our study ruled out U2506 and U2585 as contributors of vital chemical groups for transpeptidation. In contrast the ribose 2'-OH of A2451 was identified as the prime ribosomal group with potential functional importance. This 2'-OH renders almost full catalytic power to the ribosome even when embedded into an active site of six neighboring 2'-deoxyribose nucleosides. These data highlight the unique functional role of the A2451 2'-OH for peptide bond synthesis among all other functional groups at the ribosomal peptidyl transferase active site. 相似文献
803.
Emelyne Voss Axelle Arrault Jacques Bodiguel Brigitte Jamart-Grgoire 《Tetrahedron: Asymmetry》2009,20(15):1809-1812
The synthesis of enantiomerically pure orthogonally protected δ-azaproline has been performed in five steps including two successive Mitsunobu reactions starting from benzyloxycarbonylaminophthalimide and the (R)-α-hydroxy-γ-butyrolactone. 相似文献
804.
Brigitte E. Breckner Alexandru Horváth Csaba Varga 《Nonlinear Analysis: Theory, Methods & Applications》2009
We prove the existence of multiple solutions of certain systems of hemivariational inequalities, using a recent minimax result of B. Ricceri. We apply both our main theorem and the principle of symmetric criticality to obtain multiple solutions of systems of hemivariational inequalities defined on certain Sobolev spaces. 相似文献
805.
Brigitte Bauer Dr. Max Davidson Dr. Owe Orwar Prof. 《Angewandte Chemie (International ed. in English)》2009,48(9):1656-1659
A simple and scalable method is presented for harvesting, purification, and on‐chip processing of mammalian plasma membrane vesicles (PMVs) optimized for downstream proteome analysis. After immobilization on a microfluidic flowcell of PMVs, the embedded membrane proteins are proteolytically digested, and the peptides harvested and analyzed by LC‐MS/MS. Over 93 % of the detected proteins are plasma‐membrane‐derived.
806.
Brigitte Städler Dr. Rona Chandrawati Andrew D. Price Dr. Siow‐Feng Chong Kerry Breheney Almar Postma Dr. Luke A. Connal Dr. Alexander N. Zelikin Dr. Frank Caruso Prof. 《Angewandte Chemie (International ed. in English)》2009,48(24):4359-4362
Fully loaded : Noncovalent anchoring of liposomes into polymer multilayered films with cholesterol‐modified polymers allows the preparation of capsosomes—liposome‐compartmentalized polymer capsules (see picture). A quantitative enzymatic reaction confirmed the presence of active cargo within the capsosomes and was used to determine the number of subcompartments within this novel biomedical carrier system.
807.
Complex B-splines as introduced in Forster et al. (Appl. Comput. Harmon. Anal. 20:281–282, 2006) are an extension of Schoenberg’s cardinal splines to include complex orders. We exhibit relationships between these complex
B-splines and the complex analogues of the classical difference and divided difference operators and prove a generalization
of the Hermite–Genocchi formula. This generalized Hermite–Genocchi formula then gives rise to a more general class of complex
B-splines that allows for some interesting stochastic interpretations.
相似文献
808.
The scope of this study includes the synthesis of chitosan‐g‐[peptide‐poly‐ε‐caprolactone] and its self‐assembly into polymeric vesicles employing the solvent shift method. In this way, well‐defined core–shell structures suitable for encapsulation of drugs are generated. The hydrophobic polycaprolactone side‐chain and the hydrophilic chitosan backbone are linked via an enzyme‐cleavable peptide. The synthetic route involves the functionalization of chitosan with maleimide groups and the preparation of polycaprolactone with alkyne end‐groups. A peptide functionalized with a thiol group on one side and an azide group on the other side is prepared. Thiol‐ene click‐chemistry and azide–alkyne Huisgen cycloaddition are then used to link the chitosan and poly‐ε‐caprolactone chains, respectively, with this peptide. For a preliminary study, poly‐l ‐lysin is a readily available and cleavable peptide that is introduced to investigate the feasibility of the system. The size and shape of the polymersomes are studied by dynamic light scattering and cryo‐scanning electron microscopy. Furthermore, degradability is studied by incubating the polymersomes with two enzymes, trypsin and chitosanase. A dispersion of polymersomes is used to coat titanium plates and to further test the stability against enzymatic degradation. 相似文献
809.
Axel R. Brenner Brigitte I. Voit Dennis J. Massa S. Richard Turner 《Macromolecular Symposia》1996,102(1):47-54
Several hyperbranched polyesters have been prepared in a one-pot polycondensation reaction. Molecular weights, viscosities and rheological behavior of these polymers have been characterized. The influence of their terminal groups on the properties and their behavior in blends will be discussed. 相似文献
810.
Markus Antonietti Rimantas Kublickas Oskar Nuyken Brigitte Voit 《Macromolecular rapid communications》1997,18(4):287-294
Low-molar-mass surfactants (S) and polyelectrolytes (PE) containing diazosulfonate chromophores which are photo-labile and electrically charged were used for the formation of polyelectrolyte/surfactant complexes (PESC) in combination with commonly used polyelectrolytes and surfactants. The stable complexes are no longer water-soluble and were characterized by means of nuclear magnetic resonance spectroscopy and in some cases by means of gel-permeation chromatography measurements. Complexes with a 1 : 1 stoichiomctry with respect to charge are formed. Ultraviolet irradiation of the photo-labile PESC resulted in the loss of the ionic interactions. 相似文献