AIM: To investigate the expression of vascular endothelial growth factor (VEGF) and calcium-binding protein S100A4 in pancreatic cancer and their relationship to the clinicopathological parameters and prognosis of pan...AIM: To investigate the expression of vascular endothelial growth factor (VEGF) and calcium-binding protein S100A4 in pancreatic cancer and their relationship to the clinicopathological parameters and prognosis of pancreatic cancer. METHODS: Expression status of VEGF and S100A4 was examined in 62 surgical specimens of primary pancreatic cancer by immunohistochemistry. Correlation between the expression of VEGF and S100A4 and clinicopathological parameters was analyzed. RESULTS: Thirty-eight of 62 (61.3%) specimens of primary pancreatic cancer were positive for S100A4. Thirty-seven (59.7%) specimens showed positive expression of VEGF. The positive correlation between S100A4 and VEGF expression was significant in cancer tissues (P < 0.001). S100A4 expression was significantly correlated with tumor size, TNM stage and poorer prognosis. VEGF expression had a significant correlation with poorer prognosis. The prognosis of 17 S100A4-and VEGF-negative cancer patients was significantly better than that of other patients (P < 0.05). Distant metastasis (P = 0.001), S100A4-(P = 0.008) and VEGF-positive expression (P = 0.016) were significantly independent prognostic predictors (P < 0.05). CONCLUSION: Over-expression of S100A4 and VEGF plays an important role in the development of pancreatic cancer. Combined examination of the two molecules might be useful in evaluating the outcome of patients with pancreatic cancer.展开更多
Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promo...Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.展开更多
The cermet fuel element was achieved by dispersing the UO_(2)particles with or without tungsten(W)coating layer uniformly in the W matrix.It is considered to be a robust and secure fuel for use in nuclear thermal prop...The cermet fuel element was achieved by dispersing the UO_(2)particles with or without tungsten(W)coating layer uniformly in the W matrix.It is considered to be a robust and secure fuel for use in nuclear thermal propulsion in the near future.In this study,the effect of deposition temperature on the densification and grain refinement of the W coating layer was investigated.A high-density(19.24 g·cm^(-3))W layer with a uniform thickness(~10μm)and fine grains(~297 nm)was prepared by spouted-bed chemical vapor deposition.The prepared high-density,fine-grained W layer has the following advantages.It can prevent direct contact between fuel particles,resulting in a more uniform fuel distribution.In addition,it can decrease the reaction probability between the fuel kernel and H2,and prevent the release of fission products from the fuel kernel by extending the diffusion path at grain boundaries more efficiently.Moreover,the high-density,fine-grained W layer showed outstanding thermal and mechanical performance.Its average hardness and Young's modulus were approximately 7 and 200 GPa,respectively.The thermal conductivity of the W film was 101-124 W·m^(-1)·K^(-1)at 298-773 K.This work furthers our understanding of the potential application of the high-density,fine-grained W layer in nuclear thermal propulsion.展开更多
目的为获得合适的裂解力,以某款轿车发动机连杆为研究对象,应用扩展有限元法(Extended Finite Element Method,XFEM)对裂解工艺中的裂解力进行计算分析。方法根据部件的实际尺寸建立预制初始微裂纹条件下的连杆裂解有限元模型,确定相关...目的为获得合适的裂解力,以某款轿车发动机连杆为研究对象,应用扩展有限元法(Extended Finite Element Method,XFEM)对裂解工艺中的裂解力进行计算分析。方法根据部件的实际尺寸建立预制初始微裂纹条件下的连杆裂解有限元模型,确定相关的材料参数,并进行有限元网格划分,确定部件之间的约束类型。以应力强度因子大于材料断裂韧度,裂纹即扩展为依据,反复试算得出应力强度因子达到断裂韧度时的裂解力,进而通过大量计算和数据拟合得出初始微裂纹长度与裂解力之间的关系。分析裂解力对塑性区的影响,为裂解力阈值确定给出参考。结果当裂解力能够满足裂解工艺要求时,预制的初始微裂纹长度应尽可能小。结论最为理想的裂解力为材料断裂韧度对应的裂解力。文中提出的分析方法也适合于求解各类连杆的裂解力。展开更多
文摘AIM: To investigate the expression of vascular endothelial growth factor (VEGF) and calcium-binding protein S100A4 in pancreatic cancer and their relationship to the clinicopathological parameters and prognosis of pancreatic cancer. METHODS: Expression status of VEGF and S100A4 was examined in 62 surgical specimens of primary pancreatic cancer by immunohistochemistry. Correlation between the expression of VEGF and S100A4 and clinicopathological parameters was analyzed. RESULTS: Thirty-eight of 62 (61.3%) specimens of primary pancreatic cancer were positive for S100A4. Thirty-seven (59.7%) specimens showed positive expression of VEGF. The positive correlation between S100A4 and VEGF expression was significant in cancer tissues (P < 0.001). S100A4 expression was significantly correlated with tumor size, TNM stage and poorer prognosis. VEGF expression had a significant correlation with poorer prognosis. The prognosis of 17 S100A4-and VEGF-negative cancer patients was significantly better than that of other patients (P < 0.05). Distant metastasis (P = 0.001), S100A4-(P = 0.008) and VEGF-positive expression (P = 0.016) were significantly independent prognostic predictors (P < 0.05). CONCLUSION: Over-expression of S100A4 and VEGF plays an important role in the development of pancreatic cancer. Combined examination of the two molecules might be useful in evaluating the outcome of patients with pancreatic cancer.
基金supported by the National Natural Science Foundation of China,Nos.81801169 (to LXX),82071404 (to HC),81870952 (to HMW)。
文摘Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.
基金financially supported by the Thorium Molten Salt Reactor Nuclear Energy System under the Strategic Pioneer Sci.&Tech.Project of the Chinese Academy of Sciences(XDA02030200)the Frontier Science Key Program of the Chinese Academy of Sciences(Grant No.QYZDY-SSW-JSC016)+2 种基金the Natural Science Foundation of Shanghai(Grant No.20ZR1468800 and 21ZR1476300)the Natural Science Foundation of Gansu province(Grant No.20JR5RE639)the Shanghai Pujiang Program(Grant No.19pj1431600)。
文摘The cermet fuel element was achieved by dispersing the UO_(2)particles with or without tungsten(W)coating layer uniformly in the W matrix.It is considered to be a robust and secure fuel for use in nuclear thermal propulsion in the near future.In this study,the effect of deposition temperature on the densification and grain refinement of the W coating layer was investigated.A high-density(19.24 g·cm^(-3))W layer with a uniform thickness(~10μm)and fine grains(~297 nm)was prepared by spouted-bed chemical vapor deposition.The prepared high-density,fine-grained W layer has the following advantages.It can prevent direct contact between fuel particles,resulting in a more uniform fuel distribution.In addition,it can decrease the reaction probability between the fuel kernel and H2,and prevent the release of fission products from the fuel kernel by extending the diffusion path at grain boundaries more efficiently.Moreover,the high-density,fine-grained W layer showed outstanding thermal and mechanical performance.Its average hardness and Young's modulus were approximately 7 and 200 GPa,respectively.The thermal conductivity of the W film was 101-124 W·m^(-1)·K^(-1)at 298-773 K.This work furthers our understanding of the potential application of the high-density,fine-grained W layer in nuclear thermal propulsion.
文摘目的为获得合适的裂解力,以某款轿车发动机连杆为研究对象,应用扩展有限元法(Extended Finite Element Method,XFEM)对裂解工艺中的裂解力进行计算分析。方法根据部件的实际尺寸建立预制初始微裂纹条件下的连杆裂解有限元模型,确定相关的材料参数,并进行有限元网格划分,确定部件之间的约束类型。以应力强度因子大于材料断裂韧度,裂纹即扩展为依据,反复试算得出应力强度因子达到断裂韧度时的裂解力,进而通过大量计算和数据拟合得出初始微裂纹长度与裂解力之间的关系。分析裂解力对塑性区的影响,为裂解力阈值确定给出参考。结果当裂解力能够满足裂解工艺要求时,预制的初始微裂纹长度应尽可能小。结论最为理想的裂解力为材料断裂韧度对应的裂解力。文中提出的分析方法也适合于求解各类连杆的裂解力。
