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排序方式: 共有871条查询结果,搜索用时 15 毫秒
861.
Dr. Carlos Mas‐Moruno Roberta Fraioli Dr. Florian Rechenmacher Dr. Stefanie Neubauer Dr. Tobias G. Kapp Prof. Dr. Horst Kessler 《Angewandte Chemie (International ed. in English)》2016,55(25):7048-7067
Engineering biomaterials with integrin‐binding activity is a very powerful approach to promote cell adhesion, modulate cell behavior, and induce specific biological responses at the surface level. The aim of this Review is to illustrate the evolution of surface‐coating molecules in this field: from peptides and proteins with relatively low integrin‐binding activity and receptor selectivity to highly active and selective peptidomimetic ligands. In particular, we will bring into focus the difficult challenge of achieving selectivity between the two closely related integrin subtypes αvβ3 and α5β1. The functionalization of surfaces with such peptidomimetics opens the way for a new generation of highly specific cell‐instructive surfaces to dissect the biological role of integrin subtypes and for application in tissue engineering and regenerative medicine. 相似文献
862.
863.
Hatcher LE Warren MR Allan DR Brayshaw SK Johnson AL Fuertes S Schiffers S Stevenson AJ Teat SJ Woodall CH Raithby PR 《Angewandte Chemie (International ed. in English)》2011,50(36):8371-8374
One way or another: The N-bound NO(2) group in [Ni(Et(4) dien)(η(2) -O,ON)(η(1) -NO(2) )] (see structure Ni turquoise, N blue, O red) has been shown to undergo reversible conversion into the O-bound nitrito linkage isomer under both thermal and photoactivation of a single crystal. Et(4) dien=N,N,N',N'-tetraethyldiethylenetriamine. 相似文献
864.
In his paper “Kings in Bipartite Hypertournaments,” Petrovic stated two conjectures on 4-kings in multipartite hypertournaments. We prove one of these conjectures and give counterexamples for the other. 相似文献
865.
Susanne M. Tiefenthaler Marc Schlosser Florian Pielnhofer Ilya G. Shenderovich Arno Pfitzner Stefanie Gärtner 《无机化学与普通化学杂志》2020,646(3):82-87
In-depth investigations of the long-time known Zintl phase NaTl revealed a phase transition of tetragonal NaTl-tI8 [I41/amd; a = 5.2268(9) Å, c = 7.539(1) Å, V = 205.97(9) Å3] to Zintl's cubic NaTl-cF16 [Fd3 m; a = 7.4697(6) Å, V = 416.79(5) Å3] between 351 and 355 K. This phase transformation was observed for NaTl prepared by two different synthetic routes including Zintl's original procedure. An excess of sodium applied during the synthesis in liquid ammonia also resulted in the formation of NaTl-tI8. DSC measurements suggest a first order phase transition. In addition to in-situ temperature dependent powder X-ray diffraction experiments, DSC measurements and solid-state NMR investigations, we also performed theoretical DOS and band structure calculations for the cubic and tetragonal phase, respectively. The results suggest Na-Tl interactions in the second coordination sphere being responsible for the observed tetragonal distortion of Zintl's cubic NaTl. 相似文献
866.
Yingya Yang Jannik Brückmann Dr. Wolfgang Frey Prof. Dr. Sven Rau Dr. Michael Karnahl Prof. Dr. Stefanie Tschierlei 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(71):17027-17034
As a novel rylene type dye a diimine ligand with a fully rigid and extended π-system in its backbone was prepared by directly fusing a 1,10-phenanthroline building block with 1,8-naphthalimide. The corresponding heteroleptic ruthenium photosensitizer bearing one biipo and two tbbpy ligands was synthesized and extensively analyzed by a combination of NMR, single crystal X-ray diffraction, steady-state absorption and emission, time-resolved spectroscopy and different electrochemical measurements supported by time-dependent density functional theory calculations. The cyclic and differential pulse voltammograms revealed, that the naphthaloylenebenzene moiety enables an additional second reduction of the ligand. Moreover, this ligand possesses a very broad absorption in the visible region. In the RuII complex this causes an overlap of ligand-centered and metal-to-ligand charge transfer transitions. The emission of the complex is clearly redshifted compared to the ligand emission with very long-lived excited states lifetimes of 1.7 and 24.7 μs in oxygen-free acetonitrile solution. This behavior is accompanied by a surprisingly high oxygen sensitivity. Finally, this photosensitizer was successfully applied for the effective evolution of singlet oxygen challenging some of the common RuII prototype complexes. 相似文献
867.
Photoabsorption spectra of clusters, N=5–9, have been calculated using a diatomics-in-molecules like electronic structure model and a path-integral Monte Carlo sampling method. A qualitative change in the calculated spectra has been observed at N=9, which has been interpreted in terms of a structural transformation in the clusters consisting in a transition from trimer-like ionic cores observed for N≤7 to dimer-like ionic cores prevailing in through an intermediate state (comparable abundances of both types of ionic cores) observed in . The calculated spectra have been thoroughly compared with an earlier calculation on , , and reported from our group and data available for the same cluster sizes from an experiment. 相似文献
868.
869.
David Hernández-Castillo Roland E. P. Nau Marie-Ann Schmid Stefanie Tschierlei Sven Rau Leticia González 《Angewandte Chemie (International ed. in English)》2023,62(48):e202308803
Understanding the factors that determine the luminescence lifetime of transition metal compounds is key for applications in photocatalysis and photodynamic therapy. Here we show that for (bpy = 2,2’-bipyridine), the generally accepted idea that emission lifetimes can be controlled optimizing the energy barrier from the emissive triplet metal-to-ligand charge-transfer (3MLCT) state to the thermally-activated triplet metal-centered (3MC) state or the energy gap between both states is a misconception. Further, we demonstrate that considering a single relaxation pathway determined from the minimum that is lowest in energy leads to wrong temperature-dependent emission lifetimes predictions. Instead, we obtain excellent agreement with experimental temperature-dependent lifetimes when an extended kinetic model that includes all the pathways related to multiple Jahn–Teller isomers and their effective reaction barriers is employed. These concepts are essential to correctly design other luminescent transition metal complexes with tailored emission lifetimes based on theoretical predictions. 相似文献
870.
NiTi alloys open up new fields of application on the basis of their distinctive thermomechanical properties. Many options of practical application of shape memory alloys are imaginable. For example catheters or stents made of NiTi play an important role in medical technology. Thus the further development and optimisation of simulation tools for shape memory alloys (SMA) structures will play an important role in the future. Based on the powerful material model of Helm [1] the present contribution focuses on the coupling between mechanical and thermal fields. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献