Objective Gemcitabine, the only approved drug for the treatment of pancreatic cancer, is not very effective. Novel and effective cancer chemopreventive agents are urgently needed. Recently, emerging studies determined...Objective Gemcitabine, the only approved drug for the treatment of pancreatic cancer, is not very effective. Novel and effective cancer chemopreventive agents are urgently needed. Recently, emerging studies determined resveratrol possessed anticancer effects on various cancer cells. We explored the anticancer effect of resveratrol in pancreatic cancer cells and investigated the involved moleculars of action. We also examined whether resveratrol enhanced antitumor activity of gemcitabine in vitro.Methods Proliferation inhibition was assessed by cell count kit-8 assay. Cell cycle phase distribution and apoptotic cells were measured by flow cytometric analysis. We determined the expression of bcl-2, cyclinD1, and activation of caspases-3 and poly(ADP-ribose) polymerase1 proteins used Western blot analysis.Results Resveratrol inhibited the proliferation of three pancreatic cancer cell lines in a dose dependent fashion, and induced accumulation of cells at the G1 phase as well as apoptosis. Our data also demonstrated that resveratrol enhanced gemcitabine-induced apoptosis in pancreatic cancer cells. In addition, resveratrol inhibited the expression of cyclinD1, bcl-2, and induced activation of caspase-3 and poly(ADPribose) polymerase1. Conclusion Our results suggested that resveratrol might be not only a potential regimen, but also an effective chemosensitizer for the chemotherapy of pancreatic cancer.展开更多
This study aims at investigating the nonlinear dynamic behavior of rotating blade with transverse crack.A novel nonlinear rotating cracked blade model(NRCBM),which contains the spinning softening,centrifugal stiffenin...This study aims at investigating the nonlinear dynamic behavior of rotating blade with transverse crack.A novel nonlinear rotating cracked blade model(NRCBM),which contains the spinning softening,centrifugal stiffening,Coriolis force,and crack closing effects,is developed based on continuous beam theory and strain energy release rate method.The rotating blade is considered as a cantilever beam fixed on the rigid hub with high rotating speed,and the crack is deemed to be open and close continuously in a trigonometric function way with the blade vibration.It is verified by the comparison with a finite element-based contact crack model and bilinear model that the proposed NRCBM can well capture the dynamic characteristics of the rotating blade with breathing crack.The dynamic behavior of rotating cracked blade is then investigated with NRCBM,and the nonlinear damage indicator(NDI)is introduced to characterize the nonlinearity caused by blade crack.The results show that NDI is a distinguishable indicator for the severity level estimation of the crack in rotating blade.It is found that severe crack(i.e.,a closer crack position to blade root as well as larger crack depth)is expected to heavily reduce the stiffness of rotating blade and apparently result in a lower resonant frequency.Meanwhile,the super-harmonic resonances are verified to be distinguishable indicators for diagnosing the crack existence,and the third-order super-harmonic resonances can serve as an indicator for the presence of severe crack since it only distinctly appears when the crack is severe.展开更多
基金Supported by grants from the Eight Natural Science Foundation(No.81272611)Major Science and Technology Innovation Project of Hangzhou(No.20112312A01),China
文摘Objective Gemcitabine, the only approved drug for the treatment of pancreatic cancer, is not very effective. Novel and effective cancer chemopreventive agents are urgently needed. Recently, emerging studies determined resveratrol possessed anticancer effects on various cancer cells. We explored the anticancer effect of resveratrol in pancreatic cancer cells and investigated the involved moleculars of action. We also examined whether resveratrol enhanced antitumor activity of gemcitabine in vitro.Methods Proliferation inhibition was assessed by cell count kit-8 assay. Cell cycle phase distribution and apoptotic cells were measured by flow cytometric analysis. We determined the expression of bcl-2, cyclinD1, and activation of caspases-3 and poly(ADP-ribose) polymerase1 proteins used Western blot analysis.Results Resveratrol inhibited the proliferation of three pancreatic cancer cell lines in a dose dependent fashion, and induced accumulation of cells at the G1 phase as well as apoptosis. Our data also demonstrated that resveratrol enhanced gemcitabine-induced apoptosis in pancreatic cancer cells. In addition, resveratrol inhibited the expression of cyclinD1, bcl-2, and induced activation of caspase-3 and poly(ADPribose) polymerase1. Conclusion Our results suggested that resveratrol might be not only a potential regimen, but also an effective chemosensitizer for the chemotherapy of pancreatic cancer.
基金sponsored by the National Major Project of China(Grant No.2017-V-0009)the National Natural Science Foundation of China(Grant No.51705397).
文摘This study aims at investigating the nonlinear dynamic behavior of rotating blade with transverse crack.A novel nonlinear rotating cracked blade model(NRCBM),which contains the spinning softening,centrifugal stiffening,Coriolis force,and crack closing effects,is developed based on continuous beam theory and strain energy release rate method.The rotating blade is considered as a cantilever beam fixed on the rigid hub with high rotating speed,and the crack is deemed to be open and close continuously in a trigonometric function way with the blade vibration.It is verified by the comparison with a finite element-based contact crack model and bilinear model that the proposed NRCBM can well capture the dynamic characteristics of the rotating blade with breathing crack.The dynamic behavior of rotating cracked blade is then investigated with NRCBM,and the nonlinear damage indicator(NDI)is introduced to characterize the nonlinearity caused by blade crack.The results show that NDI is a distinguishable indicator for the severity level estimation of the crack in rotating blade.It is found that severe crack(i.e.,a closer crack position to blade root as well as larger crack depth)is expected to heavily reduce the stiffness of rotating blade and apparently result in a lower resonant frequency.Meanwhile,the super-harmonic resonances are verified to be distinguishable indicators for diagnosing the crack existence,and the third-order super-harmonic resonances can serve as an indicator for the presence of severe crack since it only distinctly appears when the crack is severe.
