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951.
Tsuyoshi Oshima Iori Yamanaka Anupriya Kumar Junichiro Yamaguchi Taeko Nishiwaki‐Ohkawa Kei Muto Rika Kawamura Tsuyoshi Hirota Kazuhiro Yagita Stephan Irle Steve A. Kay Takashi Yoshimura Kenichiro Itami 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(24):7299-7303
The synthesis and functional analysis of KL001 derivatives, which are modulators of the mammalian circadian clock, are described. By using cutting‐edge C H activation chemistry, a focused library of KL001 derivatives was rapidly constructed, which enabled the identification of the critical sites on KL001 derivatives that induce a rhythm‐changing activity along with the components that trigger opposite modes of action. The first period‐shortening molecules that target the cryptochrome (CRY) were thus discovered. Detailed studies on the effects of these compounds on CRY stability implicate the existence of an as yet undiscovered regulatory mechanism. 相似文献
952.
Mirjana?Bo?i? Milena?Davidovi? Teodora?L.?Dimitrova Salvador?Miret-Artés ángel?S.?Sanz Antoine?Weis 《Journal of Russian Laser Research》2010,31(2):117-128
We study experimentally and theoretically the influence of light polarization on the interference patterns behind a diffracting
grating. Different states of polarization and configurations are considered. The experiments are analyzed in terms of electromagnetic
energy (EME) flow lines, which can be eventually identified with the paths followed by photons. This gives rise to a novel
trajectory interpretation of the Arago–Fresnel laws for polarized light, which we compare with interpretations based on the
concept of “which-way” (or “which-slit”) information. 相似文献
953.
954.
Dr. Stephan G. Koller Dr. Jonathan O. Bauer Prof. Dr. Carsten Strohmann 《Angewandte Chemie (International ed. in English)》2017,56(27):7991-7994
Selective cleavage of a silicon–carbon bond in tetraorganosilanes is still a great challenge. A new type of Si−C(sp3) bond cleavage in bench-stable (aminomethyl)silanes with common organolithium reagents as nucleophiles has now been identified. Suitable leaving groups are benzyl, allyl, and phenylthiomethyl groups. A β-donor function and polar solvents are essential for the reaction. Simple switching between α-deprotonation and substitution is possible through slight modifications of the reaction conditions. The stereochemical course of the reaction was elucidated by using a silicon-chiral benzylsilane. The new transformation proceeds stereospecifically with inversion of configuration and can be used for the targeted synthesis of enantiomerically pure tetraorganosilanes, which are otherwise difficult to access. Quantum chemical calculations provided insight into the mechanism of the new substitution. 相似文献
955.
956.
Active fiber composites are electromechanical actuators based on piezo-ceramic fibers, which are embedded in a polymer matrix. The fibers are electrically contacted through so-called interdigitated electrodes (IDEs). State-of-the-art metallic IDEs only contact the fibers at two small sections of their circumference at the top and bottom of the composite ply, respectively. This paper presents an original technique to manufacture IDEs made of a conducting polymer (polypyrrole/p-toluene sulfonic acid), where the polymer electrodes contact the fibers around their whole circumference. The necessary process steps are discussed, namely design of the master electrodes and electrochemical polymer growth with and without fibers. Processing issues are discussed and solutions are suggested. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
957.
M. Capone M. Grilli W. Stephan 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(4):551-557
We investigate polaron formation in a many-electron system in the presence of a local repulsion sufficiently strong to prevent
local-bipolaron formation. Specifically, we consider a Hubbard-Holstein model of interacting electrons coupled to dispersionless
phonons of frequency . Numerically solving the model in a small one-dimensional cluster, we find that in the nearly adiabatic case , the necessary and sufficient condition for the polaronic regime to occur is that the energy gain in the atomic (i.e., extremely localized) regime overcomes the energy of the purely electronic system . In the antiadiabatic case, , polaron formation is instead driven by the condition of a large ionic displacement (g being the electron-phonon coupling). Dynamical properties of the model in the weak and moderately strong coupling regimes
are also analyzed.
Received 15 February 1999 相似文献
958.
Daniela Bertinetti Sonja Schweinsberg Susanne E Hanke Frank Schwede Oliver Bertinetti Stephan Drewianka Hans-Gottfried Genieser Friedrich W Herberg 《BMC chemical biology》2009,9(1):3-15
Background
In the eukaryotic cell the cAMP-dependent protein kinase (PKA) is a key enzyme in signal transduction and represents the main target of the second messenger cAMP. Here we describe the design, synthesis and characterisation of specifically tailored cAMP analogs which can be utilised as a tool for affinity enrichment and purification as well as for proteomics based analyses of cAMP binding proteins. 相似文献959.
960.