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991.
Natural silk from Bombyx mori has been used as medical sutures for several decades,and regenerated silk fibroin( RSF)based biomaterials have been increasingly studied in the past thirty years. However,vascular graft derived from silk fibroin fiber has been explored in recent several years with development of textile science and engineering. Moreover,endothelialization of vascular graft has been seen as an ideal strategy for preventing thrombosis and getting higher patency in a long term. Therefore,in the present work silk fibroin fiber vascular graft( SF) was chemically grafted with bioactive molecules such as heparin and RSF to improve the cytocompatibility. 3-aminopropyl-triethoxysilane(APTES),1-ethyl-3-(3-dimethylaminopropyl) carbodiie hydrochlide( EDC · HCl),and N-hydroxysuccinimide( NHS) have been employed as coupling agent and crosslinking agents,respectively. Microscopy and ATRFTIR were used to characterize the surface changes and the structure of the grafts after treatment,respectively. Cell culture in vitro and MTT assay were conducted to determine the improvement of cell affinity to the graft. Furthermore,mechanical properties of the grafts before and after treatment were compared. The results showed that the chemical grafting was an effective method for improving the cytocompatibility of SF without significant loss of mechanical properties. 相似文献
992.
叶露 《贵州师范大学学报(社会科学版)》2008,(2):104-107
文章以《莺莺传》、《霍小玉传》为切入口,认为寒门士子因追逐仕途经济之成功,不惜始乱终弃。而崔莺莺因出身甲姓,与出身卑微的霍小玉虽然处在同一时代,同为弃妇却命运殊途。作文者也因创作宗旨异趣而让后人评价不一。 相似文献
993.
高吸水性树脂的合成方法及应用前景 总被引:3,自引:0,他引:3
综述了高吸水位树脂的主要合成方法、生产概况以及应有前景,并评述了各种合成方法的优化反应条件. 相似文献
994.
Lihong Nie Zongfu Han Lahu Lu Yingyin Yao Qixin Sun Zhongfu Ni 《自然科学进展(英文版)》2008,18(5):533-538
In order to understand the genomic changes during the evolution of hexaploid wheat, two sets of synthetic hexaploid wheat from hybridization between maternal tetraploid wheat (AABB) and paternal diploid goat grass (DD) were used for DNA-AFLP and single strand conformation polymorphism (SSCP) analysis to determine the genomic and genic variation in the synthetic hexaploid wheat. Results indicated that more DNA sequences from paternal diploid species were eliminated in the synthetic hexaploid wheat than from maternal tetraploid wheat, suggesting that genome from parental species of lower ploidity tends to be eliminated preferentially. However, sequence variation detected by SSCP procedure was much lower than those detected by DNA-AFLP, which indicated that much less variation in the genic regions occurred in the synthetic hexaploid wheat, and sequence variations detected by DNA-AFLP could be derived mostly from non-coding regions and repetitive sequences. Our results also indicated that sequence variation in 4 genes can be detected in hybrid F1, which suggested that this type of sequence variation could be resulted from distant hybridization. It was interesting to note that 3 out of the 4 genes were mapped and clustered on the long arm of chromosome 2D, which indicated that variation in genic sequences in synthetic hexaploid wheat might not be a randomized process. 相似文献
995.
NECESSARY AND SUFFICIENT CONDITION FOR GLOBAL CONTROLLABILITY OF A CLASS OF AFFINE NONLINEAR SYSTEMS
Yimin SUN Shengwei MEI Qiang LU 《系统科学与复杂性》2007,20(4):492-500
In this paper, we investigate the global controllability of a class of n-dimensional affine nonlinear systems with n- 1 controls and constant control matrix. A necessary and sufficient condition for its global controllability has been obtained by using the methods recently developed. Furthermore, we generalize the above result to a class of affine nonlinear systems with a block-triangular-like structure. Finally, we will give three examples to show the applications of our results. 相似文献
996.
997.
On a kind of biharmonic boundary value problems related to clamped elastic thin plates 总被引:1,自引:0,他引:1
Lu Jian-ke 《武汉大学学报:自然科学英文版》1999,4(3):251-255
By using complex variable methods, the boundary value problem for biharmonic functions arisen from the theory of clamped elastic
thin plate is shown to be equivalent to the first fundamental problem in plane elasticity which, as well-known, may be easily
solved by reduction to a Fredholm integral equation. The case of circular plate is illustrated in detail, the solution of
which is obtained in closed form.
Foundation item: Supported by the National Natural Science Foundation of China (No. 19871064)
Biography: LU Jian-ke(1922-), male, Professor. Research interests are in applications of complex variables. 相似文献
998.
用文献资料法、调查法对重庆文理学院的地形、地貌进行研究,就重庆文理学院开展小铁人三项运动的意义、可行性等进行分析,设计了该项运动的路线图,并指出在重庆文理学院开展小铁人三项运动具有极其重要的意义和较为充分的条件. 相似文献
999.
The EM scattering from rough surface has been investigated in the past years. Periodic and random models are often used in
modeling the rough surface. Recently, the fractal geometry is rapidly improved. It provides a new way to model the rough surface
whose characteristics are long-range order and short-range disorder. In this paper, A fractal function is used to model the
rough surface. A scattering coefficient for calculating the angular distribution and the amount of energy in the spectrally
scattering field to the fractal characteristics of the surfaces by finding their analytical expressions is derived by using
the Kirchhoff solution. In the end, we calculate some scattering patterns.
Supported by the National Natural Science Foundation of China
Gao Huotao: born in 1964, Graduate student 相似文献
1000.
扬子鳄胚胎胃PAS反应观察 总被引:2,自引:0,他引:2
选取23例扬子鳄胚胎,对其胃进行PAS反应观察.胃表面上皮:第30天时,上皮细胞表面出现薄层的PAS反应阳性物质;第34~60天,阳性反应逐渐增强,并出现粘液保护层.胃腺:胃底腺,第40天腺芽上皮出现PAS反应阴性细胞,第46~60天胃底腺腺管基部上皮细胞呈阴性反应;幽门腺及贲门腺,第40天时出现腺芽,腺芽细胞呈阳性反应;第46~60天幽门腺及贲门腺腺管基部出现阴性反应细胞. 相似文献