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901.
The chemical nature of the DNA bases is an important factor in sequence-mediated association of DNA molecules. Nucleotides are the fundamental DNA elements and the base identity impacts the molecular properties of nucleotide fragments. It is interesting to study the fundamental nature of nucleotides in DNA, on the basis of base-specific interactions, association, and modes of standard atomic or molecular interactions. With all-atom molecular dynamics simulations of model dinucleotide and tetranucleotide systems having single-stranded dinucleotide or tetranucleotide fragments of varying sequences, we show how the base identity and interactions between the different bases as well as water may affect the clustering properties of nucleotides fragments in an ionic solution. Sequence-dependent differential interactions between the nucleotide fragments, ionic concentration, and elevated temperature are found to influence the clustering properties and dynamics of association. Well-known epigenetic modification of DNA, that is, cytosine methylation also promotes dinucleotide clustering in solution. These observations point to one possible chemical nature of the DNA bases, as well as the importance of the base pairing, base stacking, and ionic interactions in DNA structure formation, and DNA sequence-mediated association. Sequence- and the ionic environment-mediated self-association properties of the dinucleotides indicate its great potential to develop biological nanomaterials for desired applications. 相似文献
902.
Zhicong Lin Donghao Fan Guojiao Li Liming He Xianyan Qin Bin Zhao Qin Wang Wenlang Liang 《Macromolecular bioscience》2023,23(2):2200349
Diabetic mellitus is one of the leading causes of chronic wounds and remains a challenging issue to be resolved. Herein, a hydrogel with conformal tissue adhesivity, skin-like conductivity, robust mechanical characteristics, as well as active antibacterial function is developed. In this hydrogel, silver nanoparticles decorated polypyrrole nanotubes (AgPPy) and cobalt ions (Co2+) are introduced into an in situ polymerized poly(acrylic acid) (PAA) and branched poly(ethylenimine) (PEI) network (PPCA hydrogel). The PPCA hydrogel provides active antibacterial function through synergic effects from protonated PEI and AgPPy nanotubes, with a tissue-like mechanical property (≈16.8 ± 4.5 kPa) and skin-like electrical conductivity (≈0.048 S m−1). The tensile and shear adhesive strength (≈15.88 and ≈12.76 kPa, respectively) of the PPCA hydrogel is about two- to threefold better than that of fibrin glue. In vitro studies show the PPCA hydrogel is highly effective against both gram-positive and gram-negative bacteria. In vivo results demonstrate that the PPCA hydrogel promotes diabetic wounds with accelerated healing, with notable inflammatory reduction and prominent angiogenesis regeneration. These results suggest the PPCA hydrogel provide a promising approach to promote diabetic wound healing. 相似文献
903.
Bing Qin Zhi-Long Yu Jin Huang Yu-Feng Meng Rui Chen Zhi Chen Shu-Hong Yu 《Angewandte Chemie (International ed. in English)》2023,62(5):e202214809
Cellulose aerogels are plagued by intermolecular hydrogen bond-induced structural plasticity, otherwise rely on chemicals modification to extend service life. Here, we demonstrate a petrochemical-free strategy to fabricate superelastic cellulose aerogels by designing hierarchical structures at multi scales. Oriented channels consolidate the whole architecture. Porous walls of dehydrated cellulose derived from thermal etching not only exhibit decreased rigidity and stickiness, but also guide the microscopic deformation and mitigate localized large strain, preventing structural collapse. The aerogels show exceptional stability, including temperature-invariant elasticity, fatigue resistance (∼5 % plastic deformation after 105 cycles), high angular recovery speed (1475.4° s−1), outperforming most cellulose-based aerogels. This benign strategy retains the biosafety of biomass and provides an alternative filter material for health-related applications, such as face masks and air purification. 相似文献
904.
Wenbo Dong Zhiying Qin Kuixing Wang Yueyuan Xiao Xiangyang Liu Shijie Ren Longyu Li 《Angewandte Chemie (International ed. in English)》2023,62(5):e202216073
Imine-linked covalent organic frameworks (COFs) have been extensively studied in photocatalysis because of their easy synthesis and excellent crystallinity. The effect of imine-bond orientation on the photocatalytic properties of COFs, however, is still rarely studied. Herein, we report two novel COFs with different orientations of imine bonds using oligo(phenylenevinylene) moieties. The COFs showed similar structures but great differences in their photoelectric properties. COF-932 demonstrated a superior hydrogen evolution performance compared to COF-923 when triethanolamine was used as the sacrificial agent. Interestingly, the use of ascorbic acid led to the protonation of the COFs, further altering the direction of electron transfer. The photocatalytic performances were increased to 23.4 and 0.73 mmol g−1 h−1 for protonated COF-923 and COF-932, respectively. This study provides a clear strategy for the design of imine-linked COF-based photocatalysts and advances the development of COFs. 相似文献
905.
Dr. Yazhou Zhang Dr. Shaoqi Zhan Dr. Kunlong Liu Mengfei Qiao Ning Liu Dr. Ruixuan Qin Dr. Liangping Xiao Pengyao You Wentong Jing Prof. Nanfeng Zheng 《Angewandte Chemie (International ed. in English)》2023,62(9):e202217191
Heterogeneous hydrogenation with hydrogen spillover has been demonstrated as an effective route to achieve high selectivity towards target products. More effort should be paid to understand the complicated correlation between the nature of supports and hydrogenation involving hydrogen spillover. Herein, we report the development of the hydrogenation system of hexagonal boron nitride (h-BN)-supported Pd nanoparticles for the hydrogenation of aldehydes/ketones to alcohols with hydrogen spillover. Nitrogen vacancies in h-BN determine the feasibility of hydrogen spillover from Pd to h-BN. The hydrogenation of aldehydes/ketones with hydrogen spillover from Pd proceeds on nitrogen vacancies on h-BN. The weak adsorption of alcohols to h-BN inhibits the deep hydrogenation of aldehydes/ketones, thus leading to high catalytic selectivity to alcohols. Moreover, the hydrogen spillover-based hydrogenation mechanism makes the catalyst system exhibit a high tolerance to CO poisoning. 相似文献
906.
Shang Li Yuxing Xu Dr. Hengwei Wang Prof. Botao Teng Dr. Qin Liu Dr. Qiuhua Li Lulu Xu Xinyu Liu Prof. Junling Lu 《Angewandte Chemie (International ed. in English)》2023,62(8):e202218167
Tuning the coordination environments of metal single atoms (M1) in single-atom catalysts has shown large impacts on catalytic activity and stability but often barely on selectivity in thermocatalysis. Here, we report that simultaneously regulating both Rh1 atoms and ZrO2 support with alkali ions (e.g., Na) enables efficient switching of the reaction products from nearly 100 % CH4 to above 99 % CO in CO2 hydrogenation in a wide temperature range (240–440 °C) along with a record high activity of 9.4 molCO gRh−1 h−1 at 300 °C and long-term stability. In situ spectroscopic characterization and theoretical calculations unveil that alkali ions on ZrO2 change the surface intermediate from formate to carboxy species during CO2 activation, thus leading to exclusive CO formation. Meanwhile, alkali ions also reinforce the electronic Rh1-support interactions, endowing the Rh1 atoms more electron deficient, which improves the stability against sintering and inhibits deep hydrogenation of CO to CH4. 相似文献
907.
Xiaoliang Lu Jinzhi Zhou Jinxiu Zhao Prof. Dan Wu Xuejing Liu Prof. Xiang Ren Prof. Qin Wei Prof. Huangxian Ju 《Chemphyschem》2023,24(20):e202300536
The electrocatalytic nitrate reduction reaction (NO3−RR) enables the reduction of nitrate to ammonium ions under ambient conditions. It was considered as an alternative reaction for the production of ammonia (NH3) in recent years. In this paper, we report that the Fe doping CoS2 nanoarrays can effectively catalyze the formation of NH3 from nitrate (NO3−) under ambient conditions. This is mainly due to the increase of the NO3− reaction active site by Fe doping and the porous nanostructure of the catalyst, which greatly improves the catalytic activity. Specifically, at −0.9 V vs. RHE, the NH3 yield rate (RNH3) of Fe−CoS2/CC is 17.8×10−2 mmol h−1 cm−2 with Faraday Efficiency (FE) of 88.93 %. Besides, such catalyst shows good durability and catalytic stability, which provides the possibility for the future application of electrocatalytic NH3 production. 相似文献
908.
Gangya Wei Dr. Yunxiang Li Dr. Xupo Liu Jinrui Huang Mengran Liu Dr. Deyan Luan Prof. Shuyan Gao Prof. Xiong Wen Lou 《Angewandte Chemie (International ed. in English)》2023,62(47):e202313914
Precise manipulation of the coordination environment of single-atom catalysts (SACs), particularly the simultaneous engineering of multiple coordination shells, is crucial to maximize their catalytic performance but remains challenging. Herein, we present a general two-step strategy to fabricate a series of hollow carbon-based SACs featuring asymmetric Zn−N2O2 moieties simultaneously modulated with S atoms in higher coordination shells of Zn centers (n≥2; designated as Zn−N2O2−S). Systematic analyses demonstrate that the synergetic effects between the N2O2 species in the first coordination shell and the S atoms in higher coordination shells lead to robust discrete Zn sites with the optimal electronic structure for selective O2 reduction to H2O2. Remarkably, the Zn−N2O2 moiety with S atoms in the second coordination shell possesses a nearly ideal Gibbs free energy for the key OOH* intermediate, which favors the formation and desorption of OOH* on Zn sites for H2O2 generation. Consequently, the Zn−N2O2−S SAC exhibits impressive electrochemical H2O2 production performance with high selectivity of 96 %. Even at a high current density of 80 mA cm−2 in the flow cell, it shows a high H2O2 production rate of 6.924 mol gcat−1 h−1 with an average Faradaic efficiency of 93.1 %, and excellent durability over 65 h. 相似文献
909.
Xiaotong Li Prof. Yuan Yao Chenxi Liu Xin Jia Jiahuang Jian Bao Guo Prof. Songtao Lu Prof. Wei Qin Prof. Qing Wang Prof. Xiaohong Wu 《Angewandte Chemie (International ed. in English)》2023,62(25):e202304667
Aqueous redox flow batteries (ARFBs) are a promising technology for grid-scale energy storage, however, their commercial success relies on redox-active materials (RAM) with high electron storage capacity and cost competitiveness. Herein, a redox-active material lithium ferrocyanide (Li4[Fe(CN)6]) is designed. Li+ ions not only greatly boost the solubility of [Fe(CN)6]4− to 2.32 M at room temperature due to weak intermolecular interactions, but also improves the electrochemical performance of [Fe(CN)6]4−/3−. By coupling with Zn, ZIRFBs were built, and the capacity of the batteries was as high as 61.64 Ah L−1 (pH-neutral) and 56.28 Ah L−1 (alkaline) at a [Fe(CN)6]4− concentration of 2.30 M and 2.10 M. These represent unprecedentedly high [Fe(CN)6]4− concentrations and battery energy densities reported to date. Moreover, benefiting from the low cost of Li4[Fe(CN)6], the overall chemical cost of alkaline ZIRFB is as low as $11 per kWh, which is one-twentieth that of the state-of-the-art VFB ($211.54 per kWh). This work breaks through the limitations of traditional electrolyte composition optimization and will strongly promote the development of economical [Fe(CN)6]4−/3−-based RFBs in the future. 相似文献
910.
Tianchen Qin Prof. Dr. Dezhou Guo Juanjuan Xiong Xingyu Li Lei Hu Weishan Yang Zijie Chen Yulun Wu Dr. Honghe Ding Dr. Jun Hu Qian Xu Dr. Tao Wang Prof. Dr. Junfa Zhu 《Angewandte Chemie (International ed. in English)》2023,62(43):e202306368
The electrical and mechanical properties of graphene-based materials can be tuned by the introduction of nanopores, which are sensitively related to the size, morphology, density, and location of nanopores. The synthesis of low-dimensional graphene nanostructures containing well-defined nonplanar nanopores has been challenging due to the intrinsic steric hindrance. Herein, we report the selective synthesis of one-dimensional (1D) graphene nanoribbons (GNRs) containing periodic nonplanar [14]annulene pores on Ag(111) and two-dimensional (2D) porous graphene nanosheet containing periodic nonplanar [30]annulene pores on Au(111), starting from a same precursor. The formation of distinct products on the two substrates originates from the different thermodynamics and kinetics of coupling reactions. The reaction mechanisms were confirmed by a series of control experiments, and the appropriate thermodynamic and kinetic parameters for optimizing the reaction pathways were proposed. In addition, the combined scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations revealed the electronic structures of porous graphene structures, demonstrating the impact of nonplanar pores on the π-conjugation of molecules. 相似文献