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991.
Xiu‐Hong Yang Ming‐Xing Yang Li‐Juan Chen Jing Guo Shen Lin 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(5):369-373
The title compound, [Cd3(C8H10O4)3(C12H9N3)2(H2O)2]n or [Cd3(chdc)3(4‐PyBIm)2(H2O)2]n, was synthesized hydrothermally from the reaction of Cd(CH3COO)2·2H2O with 2‐(pyridin‐4‐yl)‐1H‐benzimidazole (4‐PyBIm) and cyclohexane‐1,4‐dicarboxylic acid (1,4‐chdcH2). The asymmetric unit consists of one and a half CdII cations, one 4‐PyBIm ligand, one and a half 1,4‐chdc2− ligands and one coordinated water molecule. The central CdII cation, located on an inversion centre, is coordinated by six carboxylate O atoms from six 1,4‐chdc2− ligands to complete an elongated octahedral coordination geometry. The two terminal rotationally symmetric CdII cations each exhibits a distorted pentagonal–bipyramidal geometry, coordinated by one N atom from 4‐PyBIm, five O atoms from three 1,4‐chdc2− ligands and one O atom from an aqua ligand. The 1,4‐chdc2− ligands possess two conformations, i.e.e,e‐trans‐chdc2− and e,a‐cis‐chdc2−. The cis‐1,4‐chdc2− ligands bridge the CdII cations to form a trinuclear {Cd3}‐based chain along the b axis, while the trans‐1,4‐chdc2− ligands further link adjacent one‐dimensional chains to construct an interesting two‐dimensional network. 相似文献
992.
Hao‐Nan Chang Bei‐Yuan Liu Yun‐Kun Qi Yang Zhou Yan‐Ping Chen Kai‐Mai Pan Wen‐Wen Li Xiu‐Man Zhou Wei‐Wei Ma Prof. Cai‐Yun Fu Prof. Yuan‐Ming Qi Prof. Lei Liu Prof. Yan‐Feng Gao 《Angewandte Chemie (International ed. in English)》2015,54(40):11760-11764
Blockade of the protein–protein interaction between the transmembrane protein programmed cell death protein 1 (PD‐1) and its ligand PD‐L1 has emerged as a promising immunotherapy for treating cancers. Using the technology of mirror‐image phage display, we developed the first hydrolysis‐resistant D ‐peptide antagonists to target the PD‐1/PD‐L1 pathway. The optimized compound DPPA‐1 could bind PD‐L1 at an affinity of 0.51 μM in vitro. A blockade assay at the cellular level and tumor‐bearing mice experiments indicated that DPPA‐1 could also effectively disrupt the PD‐1/PD‐L1 interaction in vivo. Thus D ‐peptide antagonists may provide novel low‐molecular‐weight drug candidates for cancer immunotherapy. 相似文献
993.
Xiu Gui LIU 《数学学报(英文版)》2007,23(3):385-392
In this paper, some groups Ext A^s.t (Zp, Zp) with specialized s and t are first computed by the May spectrM sequence. Then we make use of the Adams spectral sequence to prove the existence of a new nontrivial family of filtration s+5 in the stable homotopy groups of spheres πpnq+(s+3)pq+(s+1)q-5S which is represented (up to a nonzero scalar) by β+2bohh∈ExtA^s+5,P^nq+(n+3)pq+(n+1)q+s(Zp, Zp) in the Adams spectral sequence, where p ≥ 5 is a prime number, n ≥3, 0≤ s 〈 p - 3, q = 2(p - 1). 相似文献
994.
995.
Thermally reduced ruthenium nanoparticles as a highly active heterogeneous catalyst for hydrogenation of monoaromatics 总被引:1,自引:0,他引:1
Su F Lv L Lee FY Liu T Cooper AI Zhao XS 《Journal of the American Chemical Society》2007,129(46):14213-14223
We report here a thermal reduction method for preparing Ru catalysts supported on a carbon substrate. Mesoporous SBA-15 silica, surface-carbon-coated SBA-15, templated mesoporous carbon, activated carbon, and carbon black with different pore structures and compositions were employed as catalyst supports to explore the versatility of the thermal reduction method. Nitrogen adsorption, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, thermogravimetric analysis, and X-ray absorption near-edge structure techniques were used to characterize the samples. It was observed that carbon species that could thermally reduce Ru species at high temperatures played a vital role in the reduction process. Ru nanoparticles supported on various carbon-based substrates exhibited good dispersion with an appropriate particle size, high crystallinity, strong resistance against oxidative atmosphere, less leaching, lack of aggregation, and avoidance of pore blocking. As such, these catalysts display a remarkably high catalytic activity and stability in the hydrogenation of benzene and toluene (up to 3-24-fold compared with Ru catalysts prepared by traditional methods). It is believed that the excellent catalytic performance of the thermally reduced Ru nanoparticles is related to the intimate interfacial contact between the Ru nanoparticles and the carbon support. 相似文献
996.
很多关于等离子体鞘层的研究工作都是基于电子满足经典的麦克斯韦速度分布函数,而等离子体中的粒子具有长程电磁相互作用,使用Tsallis提出的非广延分布来描述电子更为恰当.本文建立一个具有非广延分布电子的碰撞等离子体磁鞘模型,理论推导出受非广延参数q影响的玻姆判据,离子马赫数的下限数值会随着参数q的增大而减小.经过数值模拟,发现与具有麦克斯韦分布(q=1)电子的碰撞等离子体磁鞘对比,具有超广延分布(q<1)和亚广延分布(q>1)电子的碰撞等离子体磁鞘的结构各有不同,包括空间电势分布、离子电子密度分布、空间电荷密度分布.模拟结果显示非广延分布的参数q对碰撞等离子体磁鞘的结构具有不可忽略的影响.希望这些结论对相关的天体物理、等离子体边界问题的研究有参考价值. 相似文献
997.
Journal of Applied Spectroscopy - Glasses coated with different thin fi lm layers exhibit different optical properties. Thus, ZnO thin films with Sn and Cr admixture (ZCTO) were deposited on the... 相似文献
998.
Xiu Hui YANG Fu Cai LI Chun Hong XIE 《数学学报(英文版)》2005,21(4):923-928
Abstract In this paper, we investigate the positive solutions of strongly coupled nonlinear parabolic systems with nonlinear boundary conditions: {ut-a(u, v)△u=g(u, v), vt-b(u, v)△v=h(u, v), δu/δη=d(u, v), δu/δη=f(u, v).Under appropriate hypotheses on the functions a, b, g, h, d and f, we obtain that the solutions may exist globally or blow up in finite time by utilizing upper and lower solution techniques. 相似文献
999.
Xiu‐Cai Chen Dr. Shuo‐Bin Chen Jing Dai Jia‐Hao Yuan Prof. Tian‐Miao Ou Prof. Zhi‐Shu Huang Prof. Jia‐Heng Tan 《Angewandte Chemie (International ed. in English)》2018,57(17):4702-4706
Because of the absence of methods for tracking RNA G‐quadruplex dynamics, especially the folding and unfolding of this attractive structure in live cells, understanding of the biological roles of RNA G‐quadruplexes is so far limited. Herein, we report a new red‐emitting fluorescent probe, QUMA‐1 , for the selective, continuous, and real‐time visualization of RNA G‐quadruplexes in live cells. The applications of QUMA‐1 in several previously intractable applications, including live‐cell imaging of the dynamic folding, unfolding, and movement of RNA G‐quadruplexes and the visualization of the unwinding of RNA G‐quadruplexes by RNA helicase have been demonstrated. Notably, our real‐time results revealed the complexity of the dynamics of RNA G‐quadruplexes in live cells. We anticipate that the further application of QUMA‐1 in combination with appropriate biological and imaging methods to explore the dynamics of RNA G‐quadruplexes will uncover more information about the biological roles of RNA G‐quadruplexes. 相似文献
1000.
Trifluoromethanesulfonic Anhydride as a Low‐Cost and Versatile Trifluoromethylation Reagent 下载免费PDF全文
Yao Ouyang Dr. Xiu‐Hua Xu Prof. Dr. Feng‐Ling Qing 《Angewandte Chemie (International ed. in English)》2018,57(23):6926-6929
A large number of reagents have been developed for the synthesis of trifluoromethylated compounds. However, an ongoing challenge in trifluoromethylation reaction is the use of less expensive and practical trifluoromethyl sources. We report herein the unprecedented direct trifluoromethylation of (hetero)arenes using trifluoromethanesulfonic anhydride as a radical trifluoromethylation reagent by merging photoredox catalysis and pyridine activation. Furthermore, introduction of both the CF3 and OTf groups of the trifluoromethanesulfonic anhydride into internal alkynes to access tetrasubstituted trifluoromethylated alkenes was achieved. Since trifluoromethanesulfonic anhydride is a low‐cost and abundant chemical, this method provides a cost‐efficient and practical route to trifluoromethylated compounds. 相似文献