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101.
102.
Xiaoming Gao Jiayi SunMing Hu Lijun WengFeng Zhou Weimin Liu 《Applied Surface Science》2011,257(17):7643-7648
Ag-Cu alloy film was deposited by arc ion plating (AIP). Atomic oxygen (AO) irradiation experiments were conducted using a ground AO simulation facility. The structure, morphology, composition and tribological property of the Ag-Cu alloy film before and after AO irradiation were investigated and compared with Ag film using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscope (XPS) and ball-on-disk tribometer, respectively. In depth XPS analysis clearly shows that the affected thickness of Ag-Cu alloy film was greatly reduced and the oxidation product was mainly Ag2O, but AgO and Ag2O in case of pure Ag film. As a result, the Ag-Cu alloy film exhibited better AO resistant behaviors, and showed a stable friction and low wear after the AO irradiation. The AO resistant behaviors of the Ag-Cu alloy film were discussed in terms of the film microstructure. 相似文献
103.
Meng Liu Jiayi Wang Yangyang Chang Qiang Zhang Dingran Chang Christy Y. Hui John D. Brennan Yingfu Li 《Angewandte Chemie (International ed. in English)》2020,59(20):7706-7710
Protein biomarkers often exist as degradation fragments in biological samples, and affinity agents derived using a purified protein may not recognize them, limiting their value for clinical diagnosis. Herein, we present a method to overcome this issue, by selecting aptamers against a degraded form of the toxin B protein, which is a marker for diagnosing toxigenic Clostridium difficile infections. This approach has led to isolation of a DNA aptamer that recognizes degraded toxin B, fresh toxin B, and toxin B spiked into human stool samples. DNA aptamers selected using intact recombinant toxin B failed to recognize degraded toxin B, which is the form present in stored stool samples. Using this new aptamer, we produced a simple paper‐based analytical device for colorimetric detection of toxin B in stool samples, or in the NAP1 strain of Clostridium difficile. The combined aptamer‐selection and paper‐sensing strategy can expand the practical utility of DNA aptamers in clinical diagnosis. 相似文献
104.
Zhang Li Jianhua Li Xuan Xu Zhen Luo Jiayi Sun Hongyun Wang Chunyan Liu Xiuwen Ni Jianqi Sun Jun Xu Kaoshan Chen 《Molecules (Basel, Switzerland)》2022,27(22)
The present study aims to analyze the structural characterization and antioxidant activity of a novel exopolysaccharide from Rhizopus nigricans (EPS2-1). For this purpose, EPS2-1 was purified through DEAE-52, Sephadex G-100, and Sephadex G-75 chromatography. The structural characterization of EPS2-1 was analyzed using high-performance gel permeation chromatography (HPGPC), Fourier transform infrared spectroscopy (FT-IR), methylation analysis, nuclear magnetic resonance (NMR) spectra, transmission electron microscope (TEM), and atomic force microscope (AFM). The results revealed that EPS2-1 is composed of mannose (Man), galactose (Gal), glucose (Glc), arabinose (Ara), and Fucose (Fuc), and possesses a molecular weight of 32.803 kDa. The backbone of EPS2-1 comprised →2)-α-D-Manp-(1→ and →3)-β-D-Galp-(1→, linked with the O-6 position of (→2,6)-α-D-Manp-(1→) of the main chain is branch α-D-Manp-(1→6)-α-D-Manp-(1→, linked with the O-6 positions of (→3)-β-D-Galp-(1→) of the main chain are branches →4)-β-D-Glcp-(1→ and →3)-β-D-Galp-(1→, respectively. Finally, we demonstrated that EPS2-1 also shows free radical scavenging activity and iron ion reducing ability. At the same time, EPS2-1 could inhibit the proliferation of MFC cells and increase the cell viability of RAW264.7 cells. Our results suggested that EPS2-1 is a novel polysaccharide, and EPS2-1 has antioxidant activity. In addition, EPS2-1 may possess potential immunomodulatory and antitumor activities. This study promoted the application of EPS2-1 as the functional ingredients in the pharmaceutical and food industries. 相似文献
105.
106.
每一位发烧友都希望自己的投入能获得预期的视觉和听觉享受,因而在决定购买器材之前都先作一系列的社会调查然后再作出决择。首先根据自己的经济能力结合实际使用需要,预计要购置多少种器材;然后详细调查这些器材的型号、性能指标、实际使用效果、设备间的合理配一K以及器材的价格,选择性能价格比高而且适合自己使用的器材。发烧友们对自己的行动计划作出如此周密的布署,按理应该取得十分满意的结果,但事实上不少人投人了大量的资金,所取得的实际效果与自己原来所要求的相距甚远。根据笔者的调查,出现这种现象的原因大多数既不是购… 相似文献
107.
Juan Feng Jiayi Shi Lan Wei Mingqing Liu Dr. Zhiming Li Prof. Dr. Yuanjing Xiao Prof. Dr. Junliang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202215407
Chiral perhydroindoles are found in a number of natural products and biologically active compounds. Therefore, the development of new asymmetric methodology for rapid access to this core is of high importance. Herein, we reported a highly regio- and diastereo-selective palladium/PC-Phos-catalyzed asymmetric Heck/Tsuji–Trost reactions of readily available amino tethered 1,3-cyclohexadienes with aryl and alkenyl halides, delivering various functionalized chiral hexahydroindoles in good yields with high enantioselectivity. The application of this reaction to the concise synthesis of (−)-α-Lycorane was demonstrated. DFT computation results indicate that the difference in ΔEdis of two migration insertion transition states determines the enantioselectivity of the reaction. 相似文献
108.
Jiayi Xu Yahui Zhang Menghan Wang Prof. Yu Gao Prof. Haijun Chen 《European journal of organic chemistry》2023,26(40):e202300833
Organic fluorophores with highly efficient luminescence in both solution and solid states have attracted significant attention due to their ability to circumvent the limitations of aggregation-caused quenching and aggregation-induced emission type molecules. However, their development and wide-range applications are hampered by extremely complex synthetic methodologies and limited frameworks with dual-state emission (DSE) structural characteristics. In sharp contrast to the reported luminogens with big and planar π systems or highly conjugated and twisted structures, we discovered novel three-dimensional scaffolds in one molecule to achieve DSE. These molecules allowing for rapid access showed completely different molecular packing manners from those of planar conjugated molecules and exhibited excellent optoelectronic properties with diminished intermolecular π−π stacking interactions due to steric hindrance. Our findings should open new avenues for designing DSE molecules with new frameworks, which will enable more successful development of dual-state emitters for their broad applications in the future. 相似文献
109.
Jiayi Li Dr. Roc Matheu Dr. Feng Ke Prof. Zhenxian Liu Dr. Yu Lin Prof. Hemamala I. Karunadasa 《Angewandte Chemie (International ed. in English)》2023,62(20):e202300957
The perovskite (BA)4[CuII(CuIInIII)0.5]Cl8 ( 1BA ; BA+=butylammonium) allows us to study the high-pressure structural, optical, and transport properties of a mixed-valence 2D perovskite. Compressing 1BA reduces the onset energy of CuI/II intervalence charge transfer from 1.2 eV at ambient pressure to 0.2 eV at 21 GPa. The electronic conductivity of 1BA increases by 4 orders of magnitude upon compression to 20 GPa, when the activation energy for conduction decreases to 0.16 eV. In contrast, CuII perovskites achieve similar conductivity at ≈50 GPa. The solution-state synthesis of these perovskites is complicated, with more undesirable side products likely from the precursor mixtures containing three different metal ions. To circumvent this problem, we demonstrate an efficient mechanochemical synthesis to expand this family of halide perovskites with complex composition by simply pulverizing together powders of 2D CuII single perovskites and CuIInIII double perovskites. 相似文献
110.
Jiayi Chen Dr. Dashuai Wang Xiaoxuan Yang Wenjun Cui Prof. Dr. Xiahan Sang Zilin Zhao Dr. Liguang Wang Dr. Zhongjian Li Dr. Bin Yang Prof. Dr. Lecheng Lei Prof. Dr. Jinyang Zheng Prof. Dr. Liming Dai Prof. Dr. Yang Hou 《Angewandte Chemie (International ed. in English)》2023,62(10):e202215406
Cu-based catalysts have been widely applied in electroreduction of carbon dioxide (CO2ER) to produce multicarbon (C2+) feedstocks (e.g., C2H4). However, the high energy barriers for CO2 activation on the Cu surface is a challenge for a high catalytic efficiency and product selectivity. Herein, we developed an in situ *CO generation and spillover strategy by engineering single Ni atoms on a pyridinic N-enriched carbon support with a sodalite (SOD) topology (Ni-SOD/NC) that acted as a donor to feed adjacent Cu nanoparticles (NPs) with *CO intermediate. As a result, a high C2H4 selectivity of 62.5 % and an industrial-level current density of 160 mA cm−2 at a low potential of −0.72 V were achieved. Our studies revealed that the isolated NiN3 active sites with adjacent pyridinic N species facilitated the *CO desorption and the massive *CO intermediate released from Ni-SOD/NC then overflowed to Cu NPs surface to enrich the *CO coverage for improving the selectivity of CO2ER to C2H4. 相似文献