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61.
温控非水液/液两相催化,是指一类由两种或多种液态有机物组成的催化反应体系,其特点是体系的相态变化可通过温度来调控,即体系在高温时相互混溶呈均相,低温不溶分成两相,催化剂和产物分别处于两相,从而为解决均相催化剂分离难的问题开拓了一个新方向,是液/液两相催化研究领域最引人注目的进展之一.首次以"温控"为主线将氟两相催化作为温控液/液两相催化的一个特定类型纳入"温控非水液/液两相催化"范畴,并与其它通过温度来调控的有机液/液两相和作者提出的温控相分离催化串在一起作一较为详细的评述. 相似文献
62.
Lei Qiao Chao Zhang Xiang‐Wen Zhang Zi‐Chuan Wang Haolin Yin Zhong‐Ming Sun 《中国化学》2020,38(3):295-304
The polypnictide complexes of rare earth cations have drawn the attention of the scientific community for their uncommon bonding modes and potential applications. Herein, we present a systematic and comprehensive summary on recent advances in the field of rare earth polypnictides, focusing on their synthesis, structures, and reactivities. The structural stabilizing effects imposed by the electropositive rare earth cations as well as the reducing capability of rare earth precursors in the synthesis of these polypnictide complexes are described in this review. We also disscuss in detail the bonding interactions and coordination modes between rare earth cations and polypnictide clusters as well as the similarities and the peculiarity of some structures. 相似文献
63.
Jin Yan Dong Ye Gao Chen Hong Chuan Song Yan Ping He Lei Li Yong Ping Zhong Yan Hui Zhu Jie Cao Luo Wang Ke Qin Zhang Laboratory for Conservation Utilization of Bioresources Yunnan University Kunming China Department of Chemistry Yunnan Normal University Kunming China Provincial Key Lab of Rural Energy Engineering Yunnan Normal University Kunming China 《中国化学快报》2007,18(2):165-167
Microbial transformation of nigranoic acid by Caryospora carllicarpa YMF1.01026 afforded the new derivative 6β-hydro-xynigranoic acid. Its structure was elucidated by spectroscopic methods. 相似文献
64.
65.
E. Ma B. S. Lim M. -A. Nicolet M. Natan 《Applied Physics A: Materials Science & Processing》1987,44(2):157-160
The growth kinetics is characterized and the moving species is identified for the formation of Ni2Si by Rapid Thermal Annealing (RTA) of sequentially deposited Si and Ni films on a 100 Si substrate. The interfacial Ni2Si layer grows as the square root of time, indicating that the suicide growth process is diffusion-limited. The activation energy is 1.25±0.2 eV in the RTA temperature range of 350–450° C. The results extend those of conventional steady-state furnace annealing quite fittingly, and a common activation energy of 1.3±0.2 eV is deduced from 225° to 450° C. The marker experiment shows that Ni is the dominant moving species during Ni2Si formation by RTA, as is the case for furnace annealing. It is concluded that the two annealing techniques induce the same growth mechanisms in Ni2Si formation. 相似文献
66.
67.
A bicyclo[3.1.0]hexane, with one cyclopropane carbon flanked by a ketone and an ester or an aldehyde, undergoes methanolysis with cleavage of one of the two activated cyclopropane bonds, depending on the reaction conditions. Acidic conditions yield primarily or exclusively a 4-methoxycyclohexane, while basic conditions yield a 3-methoxymethylcyclopentanone. 相似文献
68.
两亲性丙烯酸酯共聚物的聚合研究 总被引:1,自引:0,他引:1
利用过氧化苯甲酰为引发剂探讨了甲基丙烯酸β-羟乙酯和丙烯酸长链烷基酯的自由基共聚合。重点讨论了合成条件如溶剂、沉淀剂、引发剂用量、单体配比、反应时间等对共聚反应的影响以及各种聚合条件对该共聚物的组成、结构和性能的影响。并用IR,GPC,^13CNMR等手段对共聚物进行了表征。 相似文献
69.
Vinayak Juvekar Chang Su Lim Dong Joon Lee Sang Jun Park Gyeong Ok Song Hyuk Kang Hwan Myung Kim 《Chemical science》2021,12(1):427
Two-photon photodynamic therapy (TP-PDT) is a promising approach for the treatment of cancer because of its better penetration depth and superior spatial selectivity. Here, we describe an azo group containing cyclized-cyanine derivatives (ACC1 and ACC2) as a two-photon activated, type I based photosensitizer (PS). These small-molecule and heavy atom-free organic dyes showed marked reactive oxygen species (ROS)-generating ability under physiological conditions, as well as fast loading ability into the cells and negligible dark toxicity. Live cell analyses with one- and two-photon microscopy revealed that these dyes showed higher ROS generation ability upon two-photon excitation than upon one-photon excitation via the type I process. The PSs have superior PDT properties compared to conventional Visudyne and 5-ALA under mild conditions. These characteristics allowed for precise PDT at the target region in mimic tumor spheroids, demonstrating that the developed TP PS could be useful in efficient PDT applications and in designing various PSs.Azo containing dyes as a two-photon selective and type I based photosensitizers (PSs) were developed that exhibit excellent photodynamic therapy properties under mild condition. 相似文献
70.
CHIP-mediated hyperubiquitylation of tau promotes its self-assembly into the insoluble tau filaments
Ji Hyeon Kim Jeeyoung Lee Won Hoon Choi Seoyoung Park Seo Hyeong Park Jung Hoon Lee Sang Min Lim Ji Young Mun Hyun-Soo Cho Dohyun Han Young Ho Suh Min Jae Lee 《Chemical science》2021,12(15):5599
The tau protein is a highly soluble and natively unfolded protein. Under pathological conditions, tau undergoes multiple post-translational modifications (PTMs) and conformational changes to form insoluble filaments, which are the proteinaceous signatures of tauopathies. To dissect the crosstalk among tau PTMs during the aggregation process, we phosphorylated and ubiquitylated recombinant tau in vitro using GSK3β and CHIP, respectively. The resulting phospho–ub-tau contained conventional polyubiquitin chains with lysine 48 linkages, sufficient for proteasomal degradation, whereas unphosphorylated ub-tau species retained only one–three ubiquitin moieties. Mass-spectrometric analysis of in vitro reconstituted phospho–ub-tau revealed seven additional ubiquitylation sites, some of which are known to stabilize tau protofilament stacking in the human brain with tauopathy. When the ubiquitylation reaction was prolonged, phospho–ub-tau transformed into insoluble hyperubiquitylated tau species featuring fibrillar morphology and in vitro seeding activity. We developed a small-molecule inhibitor of CHIP through biophysical screening; this effectively suppressed tau ubiquitylation in vitro and delayed its aggregation in cultured cells including primary cultured neurons. Our biochemical findings point to a “multiple-hit model,” where sequential events of tau phosphorylation and hyperubiquitylation function as a key driver of the fibrillization process, thus indicating that targeting tau ubiquitylation may be an effective strategy to alleviate the course of tauopathies.Multiple-hit model for tau aggregation, where sequential events of tau phosphorylation and hyperubiquitylation function as a key driver of the fibrillization process. 相似文献