排序方式: 共有356条查询结果,搜索用时 15 毫秒
81.
In the course of screening new streptomycete strains, the strain Streptomyces sp. Cl 58-27 caught our attention due to its interesting secondary metabolite production profile. Here, we report the isolation and characterization of an ansamycin natural product that belongs structurally to the already known kendomycins. The structure of the new kendomycin E was elucidated using NMR spectroscopy, and the corresponding biosynthetic gene cluster was identified by sequencing the genome of Streptomyces sp. Cl 58-27 and conducting a detailed analysis of secondary metabolism gene clusters using bioinformatic tools. 相似文献
82.
Quasi-hydrostatic compression of aluminum carbide, Al4C3 has been studied to 6 GPa at room temperature using energy-dispersive X-ray powder diffraction with synchrotron radiation. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B0, of 130(5) GPa and the first pressure derivative of the bulk modulus, B′0, of 4.6(9). The compression is found to be anisotropic, with the a-axis being more compressible than the c-axis. 相似文献
83.
We show that nonlinear delayed feedback opens up novel means for the control of synchronization. In particular, we propose a demand-controlled method for powerful desynchronization, which does not require any time-consuming calibration. Our technique distinguishes itself by its robustness against variations of system parameters, even in strongly coupled ensembles of oscillators. We suggest our method for mild and effective deep brain stimulation in neurological diseases characterized by pathological cerebral synchronization. 相似文献
84.
Orest Hevus Ananiy Kohut Roman Fleychuk Natalija Mitina Oleksandr Zaichenko 《Macromolecular Symposia》2007,254(1):117-121
Summary: New anion surfmers of the family of maleic acid asymmetrical esters have been synthesized. Some of its features in the process of emulsion copolymerization with styrene have been studied. The characteristics of covering, obtained on the basis of such latexes of new generation have been investigated as well. 相似文献
85.
Dr. Oleksandr O. Grygorenko Prof. Dr. Dmitriy M. Volochnyuk Dr. Sergey V. Ryabukhin Duncan B. Judd 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(6):1196-1237
All pharmaceutical products contain organic molecules; the source may be a natural product or a fully synthetic molecule, or a combination of both. Thus, it follows that organic chemistry underpins both existing and upcoming pharmaceutical products. The reverse relationship has also affected organic synthesis, changing its landscape towards increasingly complex targets. This Review article sets out to give a concise appraisal of this symbiotic relationship between organic chemistry and drug discovery, along with a discussion of the design concepts and highlighting key milestones along the journey. In particular, criteria for a high-quality compound library design enabling efficient virtual navigation of chemical space, as well as rise and fall of concepts for its synthetic exploration (such as combinatorial chemistry; diversity-, biology-, lead-, or fragment-oriented syntheses; and DNA-encoded libraries) are critically surveyed. 相似文献
86.
87.
88.
89.
Oleksandr Vyhivskyi Anton Kudashev Takeru Miyakoshi Prof. Dr. Olivier Baudoin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(4):1231-1257
In the past few decades, processes that involve transition-metal catalysis have represented a major part of the synthetic chemist′s toolbox. Recently, the interest has shifted from the well-established cross-coupling reactions to C−H bond functionalization, thus making it a current frontier of transition-metal-catalyzed reactions. Constant progress in this field has led to the discovery of enantioselective methods to generate and control various types of stereogenic elements, thereby demonstrating its high value to generate scalemic chiral molecules. The present review is dedicated to enantioselective Pd0-catalyzed C−H activation, which may be considered as an evolution of Pd0-catalyzed cross-couplings, with a focus on the different chiral ligands and catalysts that enable these transformations. 相似文献
90.
Oliver Supplie Oleksandr Romanyuk Christian Koppka Matthias Steidl Andreas Nägelein Agnieszka Paszuk Lars Winterfeld Anja Dobrich Peter Kleinschmidt Erich Runge Thomas Hannappel 《Progress in Crystal Growth and Characterization of Materials》2018,64(4):103-132
The integration of III–V semiconductors with Si has been pursued for more than 25 years since it is strongly desired in various high-efficiency applications ranging from microelectronics to energy conversion. In the last decade, there have been tremendous advances in Si preparation in hydrogen-based metalorganic vapor phase epitaxy (MOVPE) environment, III–V nucleation and subsequent heteroepitaxial layer growth. Simultaneously, MOVPE itself took off in its triumphal course in solid state lighting production demonstrating its power as industrially relevant growth technique. Here, we review the recent progress in MOVPE growth of III–V-on-silicon heterostructures, preparation of the involved interfaces and fabrication of devices structures. We focus on a broad range of in situ, in system and ex situ characterization techniques. We highlight important contributions of density functional theory and kinetic growth simulations to a deeper understanding of growth phenomena and support of the experimental analysis. Besides new device concepts for planar heterostructures and the specific challenges of (001) interfaces, we also cover nano-dimensioned III–V structures, which are preferentially prepared on (111) surfaces and which emerged as veritable candidates for future optoelectronic devices. 相似文献