首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5篇
  免费   1篇
化学   6篇
  2014年   1篇
  2011年   1篇
  2005年   1篇
  2003年   1篇
  1997年   1篇
  1984年   1篇
排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
The introduction of two mutations (G74C/C188S) based on the estimated reaction mechanism resulted in the inversion of enantioselectivity of arylmalonate decarboxylase, which catalyses the asymmetric decarboxylation of arylmethylmalonate to give optically active arylpropionate.  相似文献   
2.
The organic-organic self-assembly method with Resorcinol (R)/Formaldehyde (F) and Pluronic F127 has been employed to synthesize mesoporous carbon (MC). The pore diameter of the MC has been tuned from 7 to 12.5 nm by changing the molar ratio of carbon sources to surfactant and polymerization time.  相似文献   
3.
Alginate/aminopropyl-silicate/alginate microcapsules, ca. 15 m in membrane thickness and ca. 500 m in diameter, were prepared via sol-gel process. The aminopropyl-silicate membrane was derived from two silicone alkoxide precursors, tetramethoxysilane and 3-aminopropyl-trimethoxysilane on Ca-alginate micro gel beads. Pancreatic -cell line (MIN6) cells were encapsulated in the microcapsule. The encapsulated MIN6 cells proliferated and formed spheroidal tissues in vitro. The diameter of the MIN6 spheroids increased to approximately 250 m with an increase in the incubation period until the day 35. Storeptozotocin-induced diabetic mice became normoglycemia after implantation of the MIN6-enclosing microcapsules. The normoglycemic state remained until the retrieval of the implanted microcapsules for 1 month. These results indicate that the potential use of the alginate/aminopropyl-silicate/alginate microcapsule as a vehicle for a genetically engineered cell-enclosing therapeutic material delivery system.  相似文献   
4.
A procedure for the simultaneous analysis of brain pipecolic acid, proline, gamma-aminobutyric acid and glycine--amino acids with potent inhibitory actions on the central nervous system--was developed. The identification and quantification of the amino acids were performed with a gas chromatographic--mass spectrometric--computer system using deuterium-labelled amino acids as the internal standards. After separation of the amino acids by high-performance liquid chromatography, the methyl ester heptafluorobutyryl derivatives were prepared. The lower limit of quantification for this method is at the picomole level. The usefulness of this chromatographic procedure has been demonstrated by measurement of trace amounts of pipecolic acid in rat brain.  相似文献   
5.
Sufficient vascularization is critical to sustaining viable tissue‐engineered (TE) constructs after implantation. Despite significant progress, current approaches lack suturability, porosity, and biodegradability, which hinders rapid perfusion and remodeling in vivo. Consequently, TE vascular networks capable of direct anastomosis to host vasculature and immediate perfusion upon implantation still remain elusive. Here, a hybrid fabrication method is presented for micropatterning fibrous scaffolds that are suturable, porous, and biodegradable. Fused deposition modeling offers an inexpensive and automated approach to creating sacrificial templates with vascular‐like branching. By electrospinning around these poly(vinyl alcohol) templates and dissolving them in water, microvascular patterns were transferred to fibrous scaffolds. Results indicated that these scaffolds have sufficient suture retention strength to permit direct anastomosis in future studies. Vascularization of these scaffolds is demonstrated by in vitro endothelialization and perfusion.  相似文献   
6.
 The new traceability system of measurement standards based on the Japanese Measurement Law has been established since November 1993. Some reference materials such as metal standard solutions, pH standard solutions and standard gas mixtures are included in the system together with relevant physical quantities. In this system, primary measurement standard instruments or primary reference materials are designated by the regulation for each quantity. For the practical dissemination of each quantity, accreditation of calibration bodies is recognized by the steering committee under the supervision of the government. In the course of assessment of a candidate calibration body, the concepts of ISO/IEC Guide 25 and ISO/IEC Guide 58 are effectively introduced. For the estimation of reliability, the concept of how to introduce the statistical approach is effectively considered. The method of uncertainty evaluation described in the ISO document entitled "Guide to the expression of uncertainty in measurement" is adopted.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号