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21.
[reaction: see text] The synthesis of allocyathin B(3) from an advanced intermediate possessing the ring system and relative stereochemistry but lacking the isopropyl and hydroxymethyl groups is reported. The isopropyl group was introduced by radical cyclization of a methyl propargyl acetal of an alpha-bromo ketone, and the hydroxymethyl group was generated by Pd-catalyzed carbonylation of a vinyl triflate. The route provides functionalized intermediates that could allow access to more complex members of the cyathin family of diterpenes. 相似文献
22.
Qiao Y Galvosas P Adalsteinsson T Schönhoff M Callaghan PT 《The Journal of chemical physics》2005,122(21):214912
Diffusion exchange of dextran with molecular weights 4.4 and 77 kDa through polyelectrolyte multilayer (PEM) hollow capsules consisting of four bilayers of polystyrene sulfonate/polydiallyldimethylammonium chloride has been investigated using two-dimensional nuclear-magnetic-resonance methods: diffusion-diffusion exchange spectroscopy (DEXSY) and diffusion-relaxation correlation spectroscopy (DRCOSY). Results obtained in DRCOSY experiments show that the diffusion process of dextran 77 kDa exhibits an observation time dependence suggesting a diffusion behavior restricted by confinement. We find evidence for both single capsule and capsule aggregate states, with a partitioning of the 77-kDa dextran between the free and capsule states much larger than that suggested by volume fraction alone. Results from DEXSY experiments show that dextran 77 kDa is in diffusive exchange through the capsules with an exchange time of around 1 s. In contrast, the capsules have no detectable influence on the diffusion process of the dextran 4.4 kDa. This quantitative information may be used in designing PEM capsules as drug carriers. 相似文献
23.
Honying M Han H Qiao C Richardson NV Yue W Jianhua Z Haiyang L Pimo H Shining B 《The Journal of chemical physics》2004,121(14):6972-6977
The structure of perylene adsorbed on Ru(0001) surface has been studied by ultraviolet photoemission spectroscopy (UPS) and low-energy electron diffraction. An ordered p(4x4) structure is observed from a monolayer (about 4 A thickness) of the perylene on Ru(0001) surface. UPS measurements show the molecular features, from the perylene multiplayer, between 2 and 10 eV below the Fermi level. Angle-resolved ultraviolet photoemission spectroscopy measurements suggest that the perylene molecular plane is parallel to the substrate. Temperature dependent UPS measurements show that the perylene multilayer is stable on Ru(0001) surface up to 125 degrees C. The desorption of the multilayer and the decomposition of the monolayer are observed above 125 degrees C. 相似文献
24.
Jiancong Du Suhui Deng Shangguo Hou Lingling Qiao Jianfang Chen Qing Huang Chunhai Fan Ya Cheng Yun Zhao 《中国光学快报(英文版)》2014,12(4):41101-38
DNA tetrahedral nanostructures are considered to be uew nanocarriers because they can be precisely controlled and hold excellent penetration ability to the cellular membrane. Although the DNA tetrahedral nanostructure is extensively studied in biology and medicine, its behavior in the cells with nanoscale resolution is not understood clearly. In this letter, we demonstrate superrcsolution fluorescence imaging of the distribution of DNA tetrahedral nanostructures in the cell with a simulated emission depletion (STED) microscope, which is built based on a conventional eonfocal microscope and can t)rovide a resolution of 70 nm. 相似文献
25.
Jie Ren Xiao Shu Ya Wang Di Wang Guangpeng Wu Xinghong Zhang Qiao Jin Jianzhao Liu Ziliang Wu Zhen Xu Chang-Zhi Li Hanying Li 《中国化学快报》2022,(4):1650-1658
In 2020, the MOE Key Laboratory of Macromolecular Synthesis and Functionalization in Zhejiang University had made progresses in several aspects. First, a series of metal-free organoboron catalysts had been designed and synthesized facilely, exhibiting outstanding reactivity, thermalstability and productivity in different kinds of polymerization and cycloaddition reactions. Second, a variety of chalcogen(O, S, Se)-rich polymers had been synthesized via organocatalysis and fabricated to be the ion... 相似文献
26.
Applied Mathematics and Mechanics - The recently developed hard-magnetic soft (HMS) materials can play a significant role in the actuation and control of medical devices, soft robots, flexible... 相似文献
27.
28.
Xiaolian Li Jiazhu Zheng Wenjuan Liu Qinglong Qiao Jie Chen Wei Zhou Zhaochao Xu 《中国化学快报》2021,31(11):2937-2940
Monitoring dynamics of mitochondria has become an essential approach to explore the function of mitochondria in living cells with the emergence of super-resolution fluorescence microscopy. However, long-term super-resolution imaging of mitochondria is still challenging due to the lack of photostable fluorescent probes and stable mitochondria-specific markers which are not affected by the changes of mitochondrial membrane potential. Here, we introduce a method for long-term imaging mitochondrial dynamic through the SNAP-tag fluorogenic probe based on 4-azetidinyl-naphthalimide derivatives. Using structured illumination microscopy (SIM), we observed the fusion and fission of mitochondria over a course of 16 min at 109 nm resolution. Furthermore, the interactions as well as fusion between mitochondria and lysosomes were studied during mitophagy at the nanoscale. Convincingly, the combination of SNAP-tag fluorogenic probes and super-resolution fluorescence microscopy will offer a new way to monitor dynamic mitochondria in living cells. 相似文献
29.
Zhongqian Qiao Wenjing Zhang Yueming Wu Weinan Jiang Ning Shao Jiayang Xie Guixue Xia Qimeng Chen Zhefeng Liu Jingcheng Zou Jiawei Gu Shifang Luan Haodong Lin Runhui Liu 《中国科学:化学(英文版)》2023,(6):1824-1833
Wound infections are a compelling health issue caused by the invasion and proliferation of pathogens in wound sites. Antibioticloaded hydrogels are widely used to achieve anti-infectious wound healing. However, due to the quick emergence of drugresistant bacteria, such as methicillin-resistant Staphylococcus aureus(MRSA), wound infection has been a formidable challenge to human health. To address MRSA-infected wounds, an antibacterial peptide polymer-loaded hyaluronic acid(HA)hydrogel(Gel-HA@P) ... 相似文献
30.
Geping Qu Deng Wang Xiaoyuan Liu Ying Qiao Danish Khan Yinxin Li Jie Zeng Pengfei Xie Yintai Xu Peide Zhu Limin Huang Yang-Gang Wang Baomin Xu Zong-Xiang Xu 《Journal of Energy Chemistry》2023,(10):39-48
Inorganic hole transport materials, particularly NiOX, have shown considerable promise in boosting the efficiency and stability of perovskite solar cells. However, a major barrier to commercialization of NiOX-based perovskite solar cells with positive-intrinsic-negative architectures is their direct contact with the absorbing layer, which can lead to losses of photovoltage and fill factor. Furthermore, highly positive under-coordinated Ni cations degrade the perovskite at t... 相似文献