The problem considered is a mode Ⅲ crack lying parallel to the interface of an exponential-type functional graded material （FGM） strip bonded to a linear-type FGM substrate with infinite thickness. By applying the ...The problem considered is a mode Ⅲ crack lying parallel to the interface of an exponential-type functional graded material （FGM） strip bonded to a linear-type FGM substrate with infinite thickness. By applying the Fourier integral transform, the problem was reduced as a Cauchy singular integral equation with an unknown dislocation density function. The collocation method based on Chebyshev polynomials proposed by Erdogan and Gupta was used to solve the singular integral equation numerically. With the numerical solution, the effects of the geometrical and physical parameters on the stress intensity factor （SIF） were analyzed and the following conclusions were drawn： （a） The region affected by the interface or free surface varies with the material rigidity, and higher material rigidity will lead to bigger affected region. （b） The SIF of the crack in the affected region and parallel to the micro-discontinuous interface is lower than those of the weak discontinuous cases. Reducing the weak-discontinuity of the interface will be beneficial to decrease the SIF of the interface-parallel crack in the region affected by the interface. （c） The effect of the free surface on SIF is more remarkable than that of the interface, and the latter is still more notable than that of the material rigidity. When the effects of the interface and free surface are fixed, increase of the material rigidity will enhance the value of SIF.展开更多
BACKGROUND： Recent studies have demonstrated that tumor necrosis factor-like weak inducer of apoptosis （TWEAK） participates in brain edema. However, it is unclear whether blood-brain barrier （BBB） disruption is a...BACKGROUND： Recent studies have demonstrated that tumor necrosis factor-like weak inducer of apoptosis （TWEAK） participates in brain edema. However, it is unclear whether blood-brain barrier （BBB） disruption is associated with TWEAK during the process of brain edema OBJECTIVE： To investigate the effects of TWEAK on BBB permeability in brain edema. DESIGN, TIME AND SETTING： An immunohistochemical observation, randomized, controlled animal experiment was performed at the Laboratory of Neurosurgical Anatomy, Xiangya Medical College, Central South University ＆ Central Laboratory, Third Xiangya Hospital, Central South University between January 2006 and December 2007. MATERIALS： A total of 48 adult Wistar rats were randomly divided into three groups： normal control （n = 8）, sham-operated （n = 8）, and ischemia/reperfusion （n = 32）. Rats from the ischemia/reperfusion group were randomly assigned to four subgroups according to different time points, i.e., 2 hours of ischemia followed by 6 hours （n = 8）, 12 hours （n = 8）, 1 day （n = 8）, or 12 days （n = 8） of reperfusion. METHODS： Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion （MCAO） using the suture method in rats from the ischemia/reperfusion group. Thread was introduced at a depth of 17-19 mm. Rats in the sham-operated group were subjected to experimental procedures similar to the ischemia/reperfusion group; however, the introducing depth of thread was 10 mm. The normal control group was not given any intervention. MAIN OUTCOME MEASURES： TWEAK expression was examined by immunohistochemistry; brain water content on the ischemic side was calculated as the ratio of dry to wet tissue weight; BBB permeability was measured by Evans blue extravasation. RESULTS： A total of eight rats died prior to and after surgery and an additional eight rats were randomly entered into the study. Thus 48 rats were included in the final analysis. In the ischemia/reperfusion group, TWEAK-positive cells were present in the ischemic penumbra surrounding the lamellar necrotic region in the fight cerebral hemisphere at 6 hours reperfusion and increased thereafter; by 2 days reperfusion they had reached a peak level, which was significantly higher than the sham-operated and normal control groups （P 〈 0.05）. At 6 hours reperfusion, both brain water content and Evans blue extravasation showed the same tendency for change as TWEAK expression. Pearson correlation analysis results revealed that the degree of TWEAK expression was positively correlated with brain water content （r = 0.892, P 〈 0.05）. CONCLUSION： The present results confirmed that TWEAK was involved in BBB disruption and participated in brain edema following cerebral ischemia.展开更多
This article obtains some theoretical results on the number of clear two-factor interaction components and weak minimum aberration in an sm-pIVdesign, by considering the number of not clear two-factor interaction comp...This article obtains some theoretical results on the number of clear two-factor interaction components and weak minimum aberration in an sm-pIVdesign, by considering the number of not clear two-factor interaction components of the design.展开更多
目的研究TWEAK和Fn14在腰椎间盘退变髓核组织中的表达及其临床意义。方法用半定量RT-PCR和免疫组织化学法检测实验组(30例退变腰椎间盘)和对照组(10例创伤腰椎间盘)中TWEAK和Fn14 mRNA及蛋白表达。结果实验组TWEAK mRNA表达显著高于对照...目的研究TWEAK和Fn14在腰椎间盘退变髓核组织中的表达及其临床意义。方法用半定量RT-PCR和免疫组织化学法检测实验组(30例退变腰椎间盘)和对照组(10例创伤腰椎间盘)中TWEAK和Fn14 mRNA及蛋白表达。结果实验组TWEAK mRNA表达显著高于对照组(0.949±0.093 vs 0.653±0.110,P<0.01),实验组TWEAK蛋白表达显著高于对照组(0.682±0.126 vs 0.397±0.057,P<0.01),实验组Fn14 mRNA表达显著高于对照组(0.936±0.125 vs 0.632±0.059,P<0.01),Fn14蛋白表达显著高于对照组(0.540±0.051 vs 0.344±0.072,P<0.01)。结论 TWEAK和Fn14的表达增加可能参与腰椎间盘退变的进程。展开更多
基金the BK 21 Program of South Korea and the National Natural Science Foundation of China(No.50574097).
文摘The problem considered is a mode Ⅲ crack lying parallel to the interface of an exponential-type functional graded material （FGM） strip bonded to a linear-type FGM substrate with infinite thickness. By applying the Fourier integral transform, the problem was reduced as a Cauchy singular integral equation with an unknown dislocation density function. The collocation method based on Chebyshev polynomials proposed by Erdogan and Gupta was used to solve the singular integral equation numerically. With the numerical solution, the effects of the geometrical and physical parameters on the stress intensity factor （SIF） were analyzed and the following conclusions were drawn： （a） The region affected by the interface or free surface varies with the material rigidity, and higher material rigidity will lead to bigger affected region. （b） The SIF of the crack in the affected region and parallel to the micro-discontinuous interface is lower than those of the weak discontinuous cases. Reducing the weak-discontinuity of the interface will be beneficial to decrease the SIF of the interface-parallel crack in the region affected by the interface. （c） The effect of the free surface on SIF is more remarkable than that of the interface, and the latter is still more notable than that of the material rigidity. When the effects of the interface and free surface are fixed, increase of the material rigidity will enhance the value of SIF.
文摘BACKGROUND： Recent studies have demonstrated that tumor necrosis factor-like weak inducer of apoptosis （TWEAK） participates in brain edema. However, it is unclear whether blood-brain barrier （BBB） disruption is associated with TWEAK during the process of brain edema OBJECTIVE： To investigate the effects of TWEAK on BBB permeability in brain edema. DESIGN, TIME AND SETTING： An immunohistochemical observation, randomized, controlled animal experiment was performed at the Laboratory of Neurosurgical Anatomy, Xiangya Medical College, Central South University ＆ Central Laboratory, Third Xiangya Hospital, Central South University between January 2006 and December 2007. MATERIALS： A total of 48 adult Wistar rats were randomly divided into three groups： normal control （n = 8）, sham-operated （n = 8）, and ischemia/reperfusion （n = 32）. Rats from the ischemia/reperfusion group were randomly assigned to four subgroups according to different time points, i.e., 2 hours of ischemia followed by 6 hours （n = 8）, 12 hours （n = 8）, 1 day （n = 8）, or 12 days （n = 8） of reperfusion. METHODS： Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion （MCAO） using the suture method in rats from the ischemia/reperfusion group. Thread was introduced at a depth of 17-19 mm. Rats in the sham-operated group were subjected to experimental procedures similar to the ischemia/reperfusion group; however, the introducing depth of thread was 10 mm. The normal control group was not given any intervention. MAIN OUTCOME MEASURES： TWEAK expression was examined by immunohistochemistry; brain water content on the ischemic side was calculated as the ratio of dry to wet tissue weight; BBB permeability was measured by Evans blue extravasation. RESULTS： A total of eight rats died prior to and after surgery and an additional eight rats were randomly entered into the study. Thus 48 rats were included in the final analysis. In the ischemia/reperfusion group, TWEAK-positive cells were present in the ischemic penumbra surrounding the lamellar necrotic region in the fight cerebral hemisphere at 6 hours reperfusion and increased thereafter; by 2 days reperfusion they had reached a peak level, which was significantly higher than the sham-operated and normal control groups （P 〈 0.05）. At 6 hours reperfusion, both brain water content and Evans blue extravasation showed the same tendency for change as TWEAK expression. Pearson correlation analysis results revealed that the degree of TWEAK expression was positively correlated with brain water content （r = 0.892, P 〈 0.05）. CONCLUSION： The present results confirmed that TWEAK was involved in BBB disruption and participated in brain edema following cerebral ischemia.
基金supported by the China Postdoctoral Science Foundation (20060390169)the Philosophy and Social Science Foundation of China (07CTJ002)+1 种基金the National Natural Science Foundation of China (10671099)Program for New Century Excellent Talents in University(NCET-08-0909)
文摘This article obtains some theoretical results on the number of clear two-factor interaction components and weak minimum aberration in an sm-pIVdesign, by considering the number of not clear two-factor interaction components of the design.
文摘目的研究TWEAK和Fn14在腰椎间盘退变髓核组织中的表达及其临床意义。方法用半定量RT-PCR和免疫组织化学法检测实验组(30例退变腰椎间盘)和对照组(10例创伤腰椎间盘)中TWEAK和Fn14 mRNA及蛋白表达。结果实验组TWEAK mRNA表达显著高于对照组(0.949±0.093 vs 0.653±0.110,P<0.01),实验组TWEAK蛋白表达显著高于对照组(0.682±0.126 vs 0.397±0.057,P<0.01),实验组Fn14 mRNA表达显著高于对照组(0.936±0.125 vs 0.632±0.059,P<0.01),Fn14蛋白表达显著高于对照组(0.540±0.051 vs 0.344±0.072,P<0.01)。结论 TWEAK和Fn14的表达增加可能参与腰椎间盘退变的进程。
