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961.
Qian Yi Han Haoyue Li Long Qiao Peng Zhao Rongmin Zhang Haiming 《Journal of Thermal Analysis and Calorimetry》2020,142(1):409-423
Journal of Thermal Analysis and Calorimetry - Layered yttrium hydroxides (LYH)- and graphene oxide (GO)-supported layered yttrium hydroxides (GO–LYH) were synthesized by a co-precipitation... 相似文献
962.
Ginseng is a vastly used herbal supplement in Southeast Asian countries. Red ginseng extract enriched with Rg3 (Rg3-RGE) is a formula that has been extensively studied owing to its various biological properties. Persicaria tinctoria (PT), belonging to the Polygonaceae family, has also been reported for its anti-inflammatory properties. Ulcerative colitis (UC) is inflammation of the large intestine, particularly in the colon. This disease is increasingly common and has high probability of relapse. We investigated, separately and in combination, the effects of Rg3-RGE and PT using murine exemplary of UC induced by DSS (Dextran Sulfate Sodium). For in vitro and in vivo experiments, nitric oxide assay, qRT-Polymerase Chain Reaction (PCR), Western blot, ulcerative colitis introduced by DSS, Enzyme Linked Immunosorbent Assay (ELISA), and flow cytometry analysis were performed. The results obtained demonstrate that treatment with Rg3-RGE + PT showed synergism to suppress inflammation (in vitro) in RAW 264.7 cells via mitogen-activated protein kinase and nuclear factor κB pathways. Moreover, in C57BL/6 mice, this mixture exhibits strong anti-inflammatory effects in restoring colon length, histopathological damage, pro-inflammatory mediators, and cytokines amount, and decreasing levels of NLRP3 inflammasome (in vivo). Our results recommend that this mixture can be used for the prevention of UC as a prophylactic/therapeutic supplement. 相似文献
963.
Han Bing-yuan Khoroshilov Andrey V. Tyurin Alexander V. Baranchikov Alexander E. Razumov Mikhail I. Ivanova Olga S. Gavrichev Konstantin S. Ivanov Vladimir K. 《Journal of Thermal Analysis and Calorimetry》2020,142(4):1533-1543
Journal of Thermal Analysis and Calorimetry - Thermodynamic properties (heat capacity Cp, entropy S°, enthalpy change ΔH° and reduced Gibbs energy ΔΦ°) of crystalline... 相似文献
964.
Lingheng Kong Xi Han Song Liu Yun Zou Yu Lan Xingwei Li 《Angewandte Chemie (International ed. in English)》2020,59(18):7188-7192
Axial‐to‐central chirality transfer is an important strategy to construct chiral centers, where the axially chiral reagents are mostly limited to atropomerically stable ones. Reported herein is a RhIII‐catalyzed enantioselective spiroannulative synthesis of nitrones. The coupling proceeds via C?H arylation to give an atropomerically metastable biaryl, followed by intramolecular dearomative trapping under oxidative conditions with high degree of chirality transfer. 相似文献
965.
Zhi‐Chao Jiang Yao‐Yu Xiao Lu Yin Li Han Yue Zhao 《Angewandte Chemie (International ed. in English)》2020,59(12):4925-4931
Novel main‐chain liquid crystalline Diels—Alder dynamic networks (LCDANs) were prepared that exhibit unprecedented ease for actuator programming and reprocessing compared to existing liquid crystalline network (LCN) systems. Following cooling from 125 °C, LCDANs are deformed with aligned mesogens self‐locked at room temperature by slowly formed Diels–Alder (DA) bonds, which allows for the formation of solid 3D actuators capable of reversible shape change, and strip walker and wheel‐capable light‐driven locomotion upon either thermally or optically induced order–disorder phase transition. Any actuator can readily be erased at 125 °C and reprogrammed into a new one under ambient conditions. Moreover, LCDANs can be processed directly from melt (for example, fiber drawing) and from solution (for example, casting tubular actuators), which cannot be achieved with LCNs using exchangeable covalent bonds. The combined attributes of LCDANs offer significant progress toward developing easily programmable/processable LCN actuators. 相似文献
966.
Jun‐Chao Liu Wei‐Qiang Liao Peng‐Fei Li Yuan‐Yuan Tang Xiao‐Gang Chen Xian‐Jiang Song Han‐Yue Zhang Yi Zhang Yu‐Meng You Ren‐Gen Xiong 《Angewandte Chemie (International ed. in English)》2020,59(9):3495-3499
Molecular ferroelectrics have attracted considerable interests because of their easy and environmentally friendly processing, low acoustical impedance and mechanical flexibility. Herein, a molecular thermochromic ferroelectric, N,N′‐dimethyl‐1,4‐diazoniabicyclo[2.2.2]octonium tetrachlorocuprate(II) ([DMe‐DABCO]CuCl4) is reported, which shows both excellent ferroelectricity and intriguing thermochromism. [DMe‐DABCO]CuCl4 undergoes a ferroelectric phase transition from Pca21 to Pbcm at a significantly high Curie temperature of 413 K, accompanied by a color change from yellow to red that is due to the remarkable deformation of [CuCl4]2? tetrahedron, where the ferroelectric and paraelectric phases correspond to yellow and red, respectively. Combined with multiple bistable physical properties, [DMe‐DABCO]CuCl4 would be a promising candidate for next‐generation smart devices, and should inspire further exploration of multifunctional molecular ferroelectrics. 相似文献
967.
Langli Luo Yao Nian Shuangbao Wang Zejian Dong Yang He You Han Chongmin Wang 《Angewandte Chemie (International ed. in English)》2020,59(6):2505-2509
By using in situ aberration‐corrected environmental transmission electron microscopy, for the first time at atomic level, the dynamic evolution of the Cu surface is captured during CO oxidation. Under reaction conditions, the Cu surface is activated, typically involving 2–3 atomic layers with the formation of a reversible metastable phase that only exists during catalytic reactions. The distinctive role of CO and O2 in the surface activation is revealed, which features CO exposure to lead to surface roughening and consequently formation of low‐coordinated Cu atoms, while O2 exposure induces a quasi‐crystalline CuOx phase. Supported by DFT calculations, it is shown that crystalline CuOx reversibly transforms into the amorphous phase, acting as an active species to facilitate the interaction of gas reactants and catalyzing CO oxidation. 相似文献
968.
Yi Han Zibo Xue Guangwu Li Yanwei Gu Yong Ni Shaoqiang Dong Chunyan Chi 《Angewandte Chemie (International ed. in English)》2020,59(23):9026-9031
Incorporation of a non‐hexagonal ring into a nanographene framework can lead to new electronic properties. During the attempted synthesis of naphthalene‐bridged double [6]helicene and heptagon‐containing nanographene by the Scholl reaction, an unexpected azulene‐embedded nanographene and its triflyloxylated product were obtained, as confirmed by X‐ray crystallographic analysis and 2D NMR spectroscopy. A 5/7/7/5 ring‐fused substructure containing two formal azulene units is formed, but only one of them shows an azulene‐like electronic structure. The formation of this unique structure is explained by arenium ion mediated 1,2‐phenyl migration and a naphthalene to azulene rearrangement reaction according to an in‐silico study. This report represents the first experimental example of the thermodynamically unfavorable naphthalene to azulene rearrangement and may lead to new azulene‐based molecular materials. 相似文献
969.
Zhoulong Fan Katherine L. Bay Xiangyang Chen Zhe Zhuang Han Seul Park Kap‐Sun Yeung K. N. Houk Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2020,59(12):4770-4777
A simple and efficient nitrile‐directed meta‐C?H olefination, acetoxylation, and iodination of biaryl compounds is reported. Compared to the previous approach of installing a complex U‐shaped template to achieve a molecular U‐turn and assemble the large‐sized cyclophane transition state for the remote C?H activation, a synthetically useful phenyl nitrile functional group could also direct remote meta‐C?H activation. This reaction provides a useful method for the modification of biaryl compounds because the nitrile group can be readily converted to amines, acids, amides, or other heterocycles. Notably, the remote meta‐selectivity of biphenylnitriles could not be expected from previous results with a macrocyclophane nitrile template. DFT computational studies show that a ligand‐containing Pd–Ag heterodimeric transition state (TS) favors the desired remote meta‐selectivity. Control experiments demonstrate the directing effect of the nitrile group and exclude the possibility of non‐directed meta‐C?H activation. Substituted 2‐pyridone ligands were found to be key in assisting the cleavage of the meta‐C?H bond in the concerted metalation–deprotonation (CMD) process. 相似文献
970.
Yiyuan Han Zhixing Lin Jiajing Zhou Gyeongwon Yun Rui Guo Joseph J. Richardson Frank Caruso 《Angewandte Chemie (International ed. in English)》2020,59(36):15618-15625
Functional materials composed of proteins have attracted much interest owing to the inherent and diverse functionality of proteins. However, establishing general techniques for assembling proteins into nanomaterials is challenging owing to the complex physicochemical nature and potential denaturation of proteins. Here, a simple, versatile strategy is introduced to fabricate functional protein assemblies through the interfacial assembly of proteins and polyphenols (e.g., tannic acid) on various substrates (organic, inorganic, and biological). The dominant interactions (hydrogen‐bonding, hydrophobic, and ionic) between the proteins and tannic acid were elucidated; most proteins undergo multiple noncovalent stabilizing interactions with polyphenols, which can be used to engineer responsiveness into the assemblies. The proteins retain their structure and function within the assemblies, thereby enabling their use in various applications (e.g., catalysis, fluorescence imaging, and cell targeting). 相似文献