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21.
High-performance frontal analysis coupled with chemiluminescence detection (HPFA-CL) was developed for the determination of unbound oxacillin concentration in human serum albumin solution. The HPFA system consisted of an ISRP column and a mobile phase of 67 mM potassium phosphate buffer of pH 7.4 and ionic strength of 0.17. The luminol-H2O2-Co2+ system was used in the chemiluminescence detection. An enhancement of luminol chemiluminescence by oxacillin was investigated and employed for determining the concentration of oxacillin in the HPFA eluate. Sample solutions were directly injected onto the column; the drug was eluted as a zonal peak with a plateau region. The unbound drug concentrations were determined by using the height of the plateau. The results agreed with those obtained with conventional ultrafiltration-HPLC method. Good reproducibility was confirmed by the within run and between run RSD < or = 7.4%. HPFA-CL provided a selective method for determination of unbound drug concentration in protein binding equilibrium. 相似文献
22.
[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
23.
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
24.
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
25.
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
26.
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
27.
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
28.
29.
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
30.
High chemical yields and good enantiomeric excesses are obtained by using soluble polymer-supported tartrate ester in the epoxidation of trans-hex-2-en-1-ol using Ti(OPri)4/tert-butyl hydroperoxide. 相似文献