A body of evidence suggests that ethanol can lead to damage of neuronal cells. However, the mechanism underlying the ethanol-induced damage of neuronal cells remains unclear. The role of mitogen-activated protein kina...A body of evidence suggests that ethanol can lead to damage of neuronal cells. However, the mechanism underlying the ethanol-induced damage of neuronal cells remains unclear. The role of mitogen-activated protein kinases in ethanol-induced damage was investigated in SK-N-SH neuroblastoma cells. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay, DNA fragmentation detection, and flow cytometric analysis showed that ethanol induced apoptotic cell death and cell cycle arrest, characterized by increased caspase-3 activity, DNA fragmentation, nuclear disruption, and G1 arrest of cell cycle of the SK-N-SH neuroblastoma cells. In addition, western blot analysis indicated that ethanol induced a lasting increase in c-Jun N-terminal protein kinase activity and a transient increase in p38 kinase activity of the neuroblastoma cells. c-Jun N-terminal protein kinase or p38 kinase inhibitors significantly reduced the ethanol-induced cell death. Ethanol also increased p53 phosphorylation, followed by an increase in p21 tumor suppressor protein and a decrease in phospho-Rb （retinoblastoma） protein, leading to alterations in the expressions and activity of cyclin dependent protein kinases. Our results suggest that ethanol mediates apoptosis of SK-N-SH neuroblastoma cells by activating p53-related cell cycle arrest possibly through activation of the c-Jun N-terminal protein kinase-related cell death pathway.展开更多
Cyclic oxidation test is a fundamental method to assess lifetime of materials in high temperature environment.Cycle length or cyclic frequency is one important variable in cyclic oxidation testing.In present work,cycl...Cyclic oxidation test is a fundamental method to assess lifetime of materials in high temperature environment.Cycle length or cyclic frequency is one important variable in cyclic oxidation testing.In present work,cyclic oxidation tests were performed on cast K38 alloys with 0 wt.%,0.1 wt.%,and 0.5 wt.% yttrium additions at 1 273 K respectively.Two cyclic frequencies were used to investigate the influence of cycle length （1 h vs.20 h） on the high temperature oxidation behavior of superalloy.The results showed that the degradation of cast K38 alloy critically was dependent on the cyclic frequency.The yttrium addition was beneficial to reducing scale-growth rate,improving the scale adhesion and stress releasing,thereby increased the spallation resistance.It could be drawn that the effect of cyclic frequency was highly dependent on the scale adherence to the substrate.展开更多
The oxidation behavior (isothermal and cyclic oxidation) of cast superalloy K38G and the effect of Ce^+ ion implantation with dose of 1×10^(17) ions/cm^2 upon its oxidation resistance at 900 and 1000 ℃ in air we...The oxidation behavior (isothermal and cyclic oxidation) of cast superalloy K38G and the effect of Ce^+ ion implantation with dose of 1×10^(17) ions/cm^2 upon its oxidation resistance at 900 and 1000 ℃ in air were investigated. Meanwhile, the influence of Ce^+ implantation on oxidation behavior of K38G with pre-oxide scale at 1000 ℃ in air was compared. The pre-oxidation was performed at 1000 ℃ in static air for 0.25 and 1.5 h, respectively. It is shown that the homogeneous external mixture oxide of rutile TiO_2+Cr_2O_3 and non-continuous internal oxide of Al_2O_3 are formed during the oxidation procedure in all the cases. The isothermal oxidation resistance and the cracking or spallation resistance of superalloy K38G implanted with Ce^+ by both of the two different implantation ways are not improved notably. This may be attributed to the mixed oxide composition characteristics and the blocking effect differences of Ce^+ segregation along the oxide grain boundaries on the transport process for different diffusing ions.展开更多
The sputtered nanocrystalline coating of K38G alloy was obtained by magnetron sput-tering. The hot corrosion behaviors of cast K38G alloy and its sputtered nanocrys-talline coating by pre-deposited 75wt%Na2SO4+25wt%K2...The sputtered nanocrystalline coating of K38G alloy was obtained by magnetron sput-tering. The hot corrosion behaviors of cast K38G alloy and its sputtered nanocrys-talline coating by pre-deposited 75wt%Na2SO4+25wt%K2SO4 at 900℃ were studied. The results indicated the occurrence of internal sulfidation in the cast K38G alloy with pre-deposited sulfattes of 0.8 and 3.0mg/cm2. However, the internal sulfidation was not observed in the coating with pre-deposited 0.8mg/cm2 sulfate. The hot corrosion resistance of K38G alloy was clearly enhanced through nanocrystallinzation, although the internal sulfides were still formed for the coating with sulfate deposit of 3mg/cm2. The relevant hot corrosion mechanism was also discussed.展开更多
基金supported by a grant from Hallym University Medical Center Research Fund,No.01-2009-15
文摘A body of evidence suggests that ethanol can lead to damage of neuronal cells. However, the mechanism underlying the ethanol-induced damage of neuronal cells remains unclear. The role of mitogen-activated protein kinases in ethanol-induced damage was investigated in SK-N-SH neuroblastoma cells. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay, DNA fragmentation detection, and flow cytometric analysis showed that ethanol induced apoptotic cell death and cell cycle arrest, characterized by increased caspase-3 activity, DNA fragmentation, nuclear disruption, and G1 arrest of cell cycle of the SK-N-SH neuroblastoma cells. In addition, western blot analysis indicated that ethanol induced a lasting increase in c-Jun N-terminal protein kinase activity and a transient increase in p38 kinase activity of the neuroblastoma cells. c-Jun N-terminal protein kinase or p38 kinase inhibitors significantly reduced the ethanol-induced cell death. Ethanol also increased p53 phosphorylation, followed by an increase in p21 tumor suppressor protein and a decrease in phospho-Rb （retinoblastoma） protein, leading to alterations in the expressions and activity of cyclin dependent protein kinases. Our results suggest that ethanol mediates apoptosis of SK-N-SH neuroblastoma cells by activating p53-related cell cycle arrest possibly through activation of the c-Jun N-terminal protein kinase-related cell death pathway.
基金Project supported by the Science and Technology Funds from Liaoning Education Department (2008564)the National Natural Science Foundation of China (50771100)
文摘Cyclic oxidation test is a fundamental method to assess lifetime of materials in high temperature environment.Cycle length or cyclic frequency is one important variable in cyclic oxidation testing.In present work,cyclic oxidation tests were performed on cast K38 alloys with 0 wt.%,0.1 wt.%,and 0.5 wt.% yttrium additions at 1 273 K respectively.Two cyclic frequencies were used to investigate the influence of cycle length （1 h vs.20 h） on the high temperature oxidation behavior of superalloy.The results showed that the degradation of cast K38 alloy critically was dependent on the cyclic frequency.The yttrium addition was beneficial to reducing scale-growth rate,improving the scale adhesion and stress releasing,thereby increased the spallation resistance.It could be drawn that the effect of cyclic frequency was highly dependent on the scale adherence to the substrate.
基金Project supported by National Outstanding Young Scientist Foundation of China (50371095) the Special Funds for the Major State Basic Research Projects (G19990650) and State Laboratory for Corrosion and Protection of Metals
文摘The oxidation behavior (isothermal and cyclic oxidation) of cast superalloy K38G and the effect of Ce^+ ion implantation with dose of 1×10^(17) ions/cm^2 upon its oxidation resistance at 900 and 1000 ℃ in air were investigated. Meanwhile, the influence of Ce^+ implantation on oxidation behavior of K38G with pre-oxide scale at 1000 ℃ in air was compared. The pre-oxidation was performed at 1000 ℃ in static air for 0.25 and 1.5 h, respectively. It is shown that the homogeneous external mixture oxide of rutile TiO_2+Cr_2O_3 and non-continuous internal oxide of Al_2O_3 are formed during the oxidation procedure in all the cases. The isothermal oxidation resistance and the cracking or spallation resistance of superalloy K38G implanted with Ce^+ by both of the two different implantation ways are not improved notably. This may be attributed to the mixed oxide composition characteristics and the blocking effect differences of Ce^+ segregation along the oxide grain boundaries on the transport process for different diffusing ions.
文摘The sputtered nanocrystalline coating of K38G alloy was obtained by magnetron sput-tering. The hot corrosion behaviors of cast K38G alloy and its sputtered nanocrys-talline coating by pre-deposited 75wt%Na2SO4+25wt%K2SO4 at 900℃ were studied. The results indicated the occurrence of internal sulfidation in the cast K38G alloy with pre-deposited sulfattes of 0.8 and 3.0mg/cm2. However, the internal sulfidation was not observed in the coating with pre-deposited 0.8mg/cm2 sulfate. The hot corrosion resistance of K38G alloy was clearly enhanced through nanocrystallinzation, although the internal sulfides were still formed for the coating with sulfate deposit of 3mg/cm2. The relevant hot corrosion mechanism was also discussed.
