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991.
Yue Zhang Wenliang Ji Shuai Zhang Nan Gao Tianci Xu Xiaofang Wang Meining Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2022,134(1):e202111853
Alpha-synuclein (α-Syn) localizes at presynaptic terminal and modulates synaptic functions. Increasing evidence demonstrate that α-Syn oligomers, forming at the early of aggregation, are cytotoxic and is thus related to brain neurodegenerative diseases. Herein, we find that vitamin D (VD) can reduce neurocytotoxicity. The reduced neurocytotoxicity might be attributed to the less amount of large-sized α-Syn oligomers inhibited by VD, measured by electrochemical collision at single particle level, which are not observable with traditionally ensembled method. Single-cell amperometry (SCA) results show that VD can recover the amount of neurotransmitter release during exocytosis induced by α-Syn oligomers, further verifying the neuroprotection of VD. Our study reveals the neuroprotective role of VD through inhibiting α-Syn aggregation, which is envisioned to be of great importance in treatment and prevention of the neurodegenerative diseases. 相似文献
992.
M. R. Ajayakumar Marco Di Giovannantonio Carlo A. Pignedoli Lin Yang Pascal Ruffieux Ji Ma Roman Fasel Xinliang Feng 《Journal of polymer science. Part A, Polymer chemistry》2022,60(12):1912-1917
The precise introduction of nonplanar pores in the backbone of graphene nanoribbon represents a great challenge. Here, we explore a synthetic strategy toward the preparation of nonplanar porous graphene nanoribbon from a predesigned dibromohexabenzotetracene monomer bearing four cove-edges. Successive thermal annealing steps of the monomers indicate that the dehalogenative aryl-aryl homocoupling yields a twisted polymer precursor on a gold surface and the subsequent cyclodehydrogenation leads to a defective porous graphene nanoribbon containing nonplanar [14]annulene pores and five-membered rings as characterized by scanning tunneling microscopy and noncontact atomic force microscopy. Although the C–C bonds producing [14]annulene pores are not achieved with high yield, our results provide new synthetic perspectives for the on-surface growth of nonplanar porous graphene nanoribbons. 相似文献
993.
Thomas Wiesner Dr. Zhu Wu Dr. Jie Han Prof. Dr. Lei Ji Dr. Alexandra Friedrich Dr. Ivo Krummenacher Michael Moos Prof. Dr. Christoph Lambert Prof. Dr. Holger Braunschweig Benjamin Rudin Dr. Hilmar Reiss Olena Tverskoy Dr. Frank Rominger Prof. Dr. Andreas Dreuw Prof. Dr. Todd B. Marder Dr. Jan Freudenberg Prof. Dr. Uwe H. F. Bunz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(69):e202201919
Tetraiodotetraazapentacene I4TAP , the last missing derivative in the series of halogenated silylated tetraazapentacenes, was synthesized via condensation chemistry from a TIPS-ethynylated diaminobenzothiadiazol in three steps. Single and double reduction furnished its air-stable monoanion and relatively air-stable dianion, both of which were characterized by crystallography. All three species are structurally and spectroscopically compared to non-halogenated TAP and Br4TAP . I4TAP is an n-channel material in thin-film transistors with average electron mobilities exceeding 1 cm2 (Vs)−1. 相似文献
994.
Sujie Yang Xiuyu Liu Gang Tang Hongming Long Bibo Wang Hao Zhang Yilong Ji Yadong Yang 《先进技术聚合物》2022,33(1):452-463
A series of FR-RPUF composites were prepared by a one-step water foaming process with ammonium polyphosphate (APP) and steel slag (SS) as flame retardants. Thermogravimetric analysis (TG), limiting oxygen index (LOI), UL-94 vertical combustion test, microscale combustion calorimetry (MCC), TG-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscopy (SEM), Raman spectra and FTIR were used to investigate the thermal stability, flame retardancy, combustion performance, gas phase products, and char residue morphology of FR-RPUF composites. TG test results showed that the initial decomposition temperature (T-5wt%) and char residue rate at 700°C of RPUF/APP/SS composites were significantly enhanced by the addition of APP and SS, and the thermal stability of the composites was improved. Flame retardant test results confirmed the significantly increased LOI values of RPUF/APP/SS composites with V-0 rating. TG-FTIR also confirmed the obviously decreased release of toxic gases and flammable gases in the combustion of RPUF/APP/SS composites. SEM and Raman spectra of char residues for the composites suggested that APP/SS system improved the compactness and graphitization degree of char layer for RPUF/APP/SS composite. The above researches provide a new strategy for the utilization of SS in fire safety engineering. 相似文献
995.
利用超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF MS)建立了猪肉中79种药物残留的非靶向定性筛查方法。猪肉样本采用0.5%(体积分数)甲酸-乙腈溶液先提取,甲醇后提取的组合提取方式,离心后上清液通过FAVEX-NM50兽药残留快速柱净化。以Acquity UPLC BEH HSS-C18色谱柱(2.1 mm × 150 mm,1.7 μm)进行分离,UPLC-Q-TOF MS电喷雾正离子模式电离,全信息串联质谱(MSE)模式检测。79种物质在相应范围内的线性关系良好,相关系数(r2)均不小于0.99,方法的检出限和定量下限分别为0.05 ~ 10 μg/kg和0.10 ~ 20 μg/kg。基于实验室自建质谱数据库,对模拟阳性样本以及市售猪肉样本进行筛查,同时使用高灵敏度Xevo TQ-S串联四极杆质谱多反应监测模式(MRM)对市售猪肉样本进行验证。结果表明,所建立的方法高效、快速、通量高,适用于猪肉中药物残留的筛查和鉴定。 相似文献
996.
Prof. Dr. Tsutomu Ishi-i Honoka Tanaka Rihoko Kichise Christopher Davin Takaaki Matsuda Dr. Naoya Aizawa Dr. In Seob Park Prof. Dr. Takuma Yasuda Taisuke Matsumoto 《化学:亚洲杂志》2021,16(15):2136-2145
The regulation of multicolor fluorescence changes in mechanochromic fluorescence (MCF) remains a challenging task. Herein, we report the regulation of MCF using a donor-acceptor structure. Two crystal polymorphs, BTD-pCHO(O) and BTD-pCHO(R) produced by the introduction of formyl groups to an MCF dye, respond to a mechanical stimulus, allowing a three-color fluorescence change. Specifically, the orange-colored fluorescence of the metastable BTD-pCHO(O) polymorph changed to a deep-red color in the amorphous-like state to finally give a red color in the stable BTD-pCHO(R) polymorph. This change occurred by mechanical grinding followed by vapor fuming. The two different crystal packing patterns were selectively regulated by the electronic effect of the introduced functional groups. The two types of selectively formed crystals in BTD(F)-pCHO bearing fluorine atoms, and BTD(OMe)-pCHO bearing methoxy groups, respond to mechanical grinding, allowing for the regulation of multicolor MCL from a three-color change to two different types of two-color changes. 相似文献
997.
Developing ideal IR probes is essential to understand the structure and dynamics of biomolecules with time-resolved IR spectroscopies and imaging techniques. Especially, nitrile (CN) group has recently been proposed to serve as IR probes of the local environment of proteins. Herein, we investigated the effect of a substituent on the vibrational properties of the benzonitrile. The electron-donating and withdrawing character of p-substituent on benzonitrile are expected to modulate the vibrational frequency, molar extinction coefficient, and vibrational lifetime of CN probe. FT-IR revealed the positive correlation between electron-donating character and the molar extinction coefficient of CN stretch mode. Infrared pump-probe (IR-PP) measurements showed that the vibrational lifetime of CN stretch mode exhibits a relatively weak correlation with the electron-donating strength. Among the investigated samples, 4-dimethylamino benzonitrile with the strongest electron-donating strength shows enhanced absorption and extended vibrational lifetime. Utilizing substituent effects will be a practical strategy to improve the performance of the IR probe. 相似文献
998.
H2-SCR is served as the promising technology for the controlling of NOx emission, and the Pd-based derivative catalyst exhibited high NOx reduction performance. Effectively regulating the electronic configuration of the active component is favorable to the rational optimization of noble Pd. In this work, a series of Pr1-xCexMn1-yPdyO3@Ni were successfully synthesized and exhibited superior NO conversion efficiency at low temperatures. 92.7 % conversion efficiency was achieved at 200 °C over Pr0.9Ce0.1Mn0.9Pd0.1O3@Ni in the presence of 4 % O2 with a GHSV of 32000 h−1. Meanwhile, the outstanding performance was obtained in the resistance to SO2 (200 ppm) and H2O (8 %). Deduced from the results of XRD, Raman, XPS, and H2-TPR, the modification of d orbit states in palladium was confirmed originating from the incorporation in the B site of Pr0.9Ce0.1Mn0.9Pd0.1O3. The existence of higher valence (Pd3+ and Pd4+) than the bivalence in Pr0.9Ce0.1Mn0.9Pd0.1O3 catalyst was evidenced by XPS analysis. Our research provides a new sight into the H2-SCR through the higher utilization of Pd. 相似文献
999.
Devendra KC Deb Kumar Shah M. Shaheer Akhtar Mira Park Chong Yeal Kim O-Bong Yang Bishweshwar Pant 《Molecules (Basel, Switzerland)》2021,26(11)
This paper numerically explores the possibility of ultrathin layering and high efficiency of graphene as a back surface field (BSF) based on a CdTe solar cell by Personal computer one-dimensional (PC1D) simulation. CdTe solar cells have been characterized and studied by varying the carrier lifetime, doping concentration, thickness, and bandgap of the graphene layer. With simulation results, the highest short-circuit current (Isc = 2.09 A), power conversion efficiency (η = 15%), and quantum efficiency (QE~85%) were achieved at a carrier lifetime of 1 × 103 μs and a doping concentration of 1 × 1017 cm−3 of graphene as a BSF layer-based CdTe solar cell. The thickness of the graphene BSF layer (1 μm) was proven the ultrathin, optimal, and obtainable for the fabrication of high-performance CdTe solar cells, confirming the suitability of graphene material as a BSF. This simulation confirmed that a CdTe solar cell with the proposed graphene as the BSF layer might be highly efficient with optimized parameters for fabrication. 相似文献
1000.
Yueteng Zhang Peng Ji Xiang Meng Feng Gao Fanxun Zeng Wei Wang 《Molecules (Basel, Switzerland)》2021,26(12)
A simple arylamine-catalyzed Mannich-cyclization cascade reaction was developed for facile synthesis of substituted 2H-benzo[h]chromenes. The notable feature of the process included the efficient generation of ortho-quinone methides (o-QMs) catalyzed by a simple aniline. The mild reaction conditions allowed for a broad spectrum of 1- and 2-naphthols and trans-cinnamaldehydes to engage in the cascade sequence with high efficiency. 相似文献