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971.
The FabH enzyme from M. tuberculosis binds the acyl tail of large substrates at the end of a buried hydrophobic tunnel. Sachdeva et al. (2008) use reactive chemical probes and X-ray crystallography to show that substrates can bind to an open state of FabH without threading through the tunnel. 相似文献
972.
Cairong Zhang Hongshan Chen Yuhong Chen Zhiqiang Wei Zhongsheng Pu 《Acta Physico》2008,24(8):1353-1358
Density functional theory (DFT) and time-dependent density functional theory (TDDFT) with hybrid functional B3LYP were used to investigate several physical and chemical properties of [6,6]-phenyl-C61 butyric acid methyl ester (PCBM), including the geometry, electron structure, charge population, bond properties, as well as IR, Raman and electronic absorption spectra. The analysis of the natural bond orbital (NBO) suggested that there were about 0.11 electrons transferred from moiety phenyl and butyric acid methyl ester group of PCBM to fullerene cage. The strongest IR and Raman peaks came from different modes with the frequencies of 1773 and 1492 cm−1, respectively. The calculated isotropic polarizability, polarizability anisotropy invariant, and hyperpolarizability were 577.7, 96.9, and −22.8 a.u., respectively. Based on TDDFT, the electronic absorption spectra of PCBM were calculated and analyzed. The calculated absorption band near 349 nm agreed well with the experimental measurement. 相似文献
973.
This paper deals with the global exact controllability for first-order quasilinear hyperbolic systems of diagonal form with linearly degenerate characteristics. When the system has no zero characteristics, we establish the global exact boundary controllability from one arbitrarily preassigned C1 data to another by means of a constructive method, in which the desired boundary controls can be acted either on both sides or only on one side. Sharp estimates on the exact controllable time are given in both cases. When the system has some zero characteristics, the global exact controllability is also established. 相似文献
974.
975.
Meng-Hao Li Zhiqiang Yang Hui Hui Prof. Bing Yang Prof. Yan Wang Prof. Ying-Wei Yang 《Angewandte Chemie (International ed. in English)》2023,62(47):e202313358
Most attempts to synthesize supramolecular nanosystems are limited to a single mechanism, often resulting in the formation of nanomaterials that lack diversity in properties. Herein, hierarchical assemblies with appropriate variety are fabricated in bulk via a superstructure-induced organic–inorganic hybrid strategy. The dynamic balance between substructures and superstructures is managed using covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) as dual building blocks to regulate the performances of hierarchical assemblies. Significantly, the superstructures resulting from the controlled cascade between COFs and MOFs create highly active photocatalytic systems through multiple topologies. Our designed tandem photocatalysis can precisely and efficiently regulate the conversion rates of bioactive molecules (benzo[d]imidazoles) through competing redox pathways. Furthermore, benzo[d]imidazoles catalyzed by such supramolecular nanosystems can be isolated in yields ranging from 70 % to 93 % within tens of minutes. The multilayered structural states within the supramolecular systems demonstrate the importance of hierarchical assemblies in facilitating photocatalytic propagation and expanding the structural repertoire of supramolecular hybrids. 相似文献
976.
Songshan Bi Yanyu Zhang Huimin Wang Prof. Jinlei Tian Prof. Zhiqiang Niu 《Angewandte Chemie (International ed. in English)》2023,62(49):e202312172
Lithium||sulfur (Li||S) batteries are considered as one of the promising next-generation batteries due to the high theoretical capacity and low cost of S cathodes, as well as the low redox potential of Li metal anodes (−3.04 V vs. standard hydrogen electrode). However, the S reduction reaction from S to Li2S leads to limited discharge voltage and capacity, largely hindering the energy density of Li||S batteries. Herein, high-energy Li||S hybrid batteries were designed via an electrolyte decoupling strategy. In cathodes, S electrodes undergo the solid-solid conversion reaction from S to Cu2S with four-electron transfer in a Cu2+-based aqueous electrolyte. Such an energy storage mechanism contributes to enhanced electrochemical performance of S electrodes, including high discharge potential and capacity, superior rate performance and stable cycling behavior. As a result, the assembled Li||S hybrid batteries exhibit a high discharge voltage of 3.4 V and satisfactory capacity of 2.3 Ah g−1, contributing to incredible energy density. This work provides an opportunity for the construction of high-energy Li||S batteries. 相似文献
977.
Songshan Bi Huimin Wang Yanyu Zhang Min Yang Qingjie Li Jinlei Tian Prof. Zhiqiang Niu 《Angewandte Chemie (International ed. in English)》2023,62(49):e202312982
Iodine (I2) shows great promising as the active material in aqueous batteries due to its distinctive merits of high abundance in ocean and low cost. However, in conventional aqueous I2-based batteries, the energy storage mechanism of I−/I2 conversion is only two-electron redox reaction, limiting their energy density. Herein, six-electron redox chemistry of I2 electrodes is achieved via the synergistic effect of redox-ion charge-carriers and halide ions in electrolytes. The redox-active Cu2+ ions in electrolytes induce the conversion between Cu2+ ions and I2 to CuI at low potential. Simultaneously, the Cl− ions in electrolytes activate the I2/ICl redox couple at high potential. As a result, in our case, I2-based battery system with six-electron redox is developed. Such energy storage mechanism with six-electron redox leads to high discharge potential and capacity, excellent rate capability, as well as stable cycling behavior of I2 electrodes. Impressively, six-electron-redox I2 cathodes can match various aqueous metal (e.g. Zn, Mn and Fe) anodes to construct metal||I2 hybrid batteries. These hybrid batteries not only deliver enhanced capacities, but also exhibit higher operate voltages, which contributes to superior energy densities. Therefore, this work broadens the horizon for the design of high-energy aqueous I2-based batteries. 相似文献
978.
Mengdan Zhang Dr. Jian Cheng Dr. Zhiqiang Shen Paiyu Lin Prof. Dr. Shenggang Ding Prof. Dr. Jinming Hu 《Angewandte Chemie (International ed. in English)》2023,62(52):e202314563
The development of dual gasotransmitter donors can not only provide robust tools to investigate their subtle interplay under pathophysiological conditions but also optimize therapeutic efficacy. While conventional strategies are heavily dependent on multicomponent donors, we herein report an ultrasound-responsive water-soluble copolymer ( PSHF ) capable of releasing carbon monoxide (CO) and hydrogen sulfide (H2S) based on single-component sulfur-substituted 3-hydroxyflavone (SHF) derivatives. Interestingly, sulfur substitution can not only greatly improve the ultrasound sensitivity but also enable the co-release of CO/H2S under mild ultrasound irradiation. The co-release of CO/H2S gasotransmitters exerts a bactericidal effect against Staphylococcus aureus and demonstrates anti-inflammatory activity in lipopolysaccharide-challenged macrophages. Moreover, the excellent tissue penetration of ultrasound irradiation enables the local release of CO/H2S in the joints of septic arthritis rats, exhibiting superior therapeutic efficacy without the need for any antibiotics. 相似文献
979.
Xiaoyu Luan Dr. Lu Qi Zhiqiang Zheng Yaqi Gao Prof. Yurui Xue Prof. Yuliang Li 《Angewandte Chemie (International ed. in English)》2023,62(8):e202215968
Rechargeable aqueous zinc ion batteries (AZIBs) promise high energy density, low redox potential, low cost and safety; however, their cycle performances are seriously insufficient to restrict the progress in this field. We propose a new concept of atomic electrode formed on the graphdiyne (GDY). This new idea electrode was synthesized by selectively, uniformly, and stably anchoring Zn atoms on GDY at the beginning of plating. The Zn atoms are induced to grow into larger size Zn clusters, which continue to grow into nanoflat. Finally, a new heterojunction interface is formed on GDY without any Zn dendrites and side reactions, even at high current densities. Such stepwise induction of growth greatly suppresses the formation of Zn dendrites, resulting in high electroplating/stripping reversibility and lifespan of AZIBs. 相似文献
980.
Dr. Zhiqiang Shen Shaoqiu Zheng Yuanmeng Fang Prof. Dr. Guoying Zhang Prof. Dr. Chen Zhu Prof. Dr. Shiyong Liu Prof. Dr. Jinming Hu 《Angewandte Chemie (International ed. in English)》2023,62(20):e202219153
The peroxynitrite anion (ONOO−) is closely associated with many diseases and the creation of ONOO− donors is an essential means of understanding its pathophysiological functions. However, it is challenging to develop ONOO− donors due to the difficulties in simultaneously producing highly reactive and short-lived nitric oxide (NO) and superoxide anion (O2⋅−). Here, we report a novel strategy for constructing ONOO− donors by combining near-infrared (NIR)-mediated type I photosensitization and photoredox catalysis. The key design using a Nile blue analogue that can serve as both a type I photosensitizer and a metal-free photocatalyst. Intriguingly, the formation of O2⋅− via type I photosensitization avoids oxygen interference and instead activates nitrobenzofurazan-based NO donors via oxygen-tolerant NIR photoredox catalysis. The simultaneous release of O2⋅− and NO leads to ONOO− release, showing both antibacterial and antibiofilm activities. 相似文献