http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Modular synthesis of heparanase substrates
Peng Xu,Weichang Xu,Yuanwei Dai,Biao Yu 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1
Heparanase, preferentially expressed in many tumor cells, is an endoβDglucuronidase that cleaves specific sites of heparan sulfate. Elevated levels of heparanase expression correlate with tumor vasculatrity, metastatic potiential, and reduced postoperative survival of cancer patients. Consequencely, heparanase detection is considered a tool for cancer discovery. A library of 20 welldefined Tetra1 analogs were prepared in a convergent “2+2” glycosidation manner utilizing a relatively small number of protected disaccharide donors and acceptors. Among three different donors prepared for the fullprotected tetrasaccharide, trifluoroacetimidate donor was most suitable for the preservation and glycosidation reaction, and in each glycosylation, the yield was good and the major anomer was obtained. After coupling these 12 glycosydic reactions, the observation indicate that the coupling ratio is not only relating to the structure and exact nature of acceptors, but also correlated to the structure and size of donors. Key features of the approach include the use of Bz esters or PMB ethers for those hydroxyls that need sulfation, regioselective opening of the 4,6-O-benzylidene acetal for 4OBn that don’t need sulfation and 6OH that need oxidation, an anomeric TBS group for glycosyl donor synthesis, and benzyl ethers just as permanent protecting groups. The HS oligosaccharides will be employed to probe structural features of HS for cleavage of heparanase.
Optimization of a crossbar parallel machine tool based on workspace and dexterity
Fang Xifeng,Zhang Sichong,Xu Qinhuan,Wang Tongyue,Liu Yuanwei,Chen Xiaogang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8
Increasing workspace and improving dexterity are important tasks for the design of parallel machine tools. The workspace of a crossbarparallel machine tool with constraints is obtained by using a 3D search method based on inverse kinematics. The new Jacobian matrixof the machine is also derived by using the natural coordinate method. Dexterity distribution of the machine tool is obtained on the basisof the workspace and the new Jacobian matrix. Influences of the structural parameters on the workspace volume index (WVI) and globaldexterity index (GDI) are analyzed. Structural optimization is conducted by treating the WVI and GDI as the global optimization goals. Unlike the initial data, the optimized results increased by 0.43 and 0.34 times.
Huaifen Su,Xiaoxue Wang,Yuanwei Sun,Dan Xu,Lei Li,Caihua Liu,Suyuan Zeng,Dezhi Sun 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.10
This work aims to provide a facile method for the preparation of Mn-doped hematite microrods and reveals the relationship between Mn doping and the enhanced adsorption properties. The adsorption performance of hematite could be greatly enhanced by Mn doping. The maximal adsorption capacity of the Mn-doped α-Fe2O3 is calculated to be 84.54 mg/g, which exhibits obviously enhanced adsorption capacity as compared to the un-doped α-Fe2O3 (33.02 mg/g). To further understand the adsorption process, the adsorption kinetic as well as thermodynamic behaviors are carefully investigated. The results suggest that the adsorption process of CR onto the adsorbents follows the pseudo-second-order kinetic model. Meanwhile, the adsorption process can be designated to be a Langmuir process. The adsorption capacities of CR vary as a function of Mn contents, which are regarded as the synergistic effect between surface areas and pore sizes.