To clarify the corrosion mechanism associated with the precipitate of T1(Al2CuLi)in Al-Li alloys,the simulated bulk precipitate of T1 was fabricated through melting and casting.Its electrochemical behavior and couplin...To clarify the corrosion mechanism associated with the precipitate of T1(Al2CuLi)in Al-Li alloys,the simulated bulk precipitate of T1 was fabricated through melting and casting.Its electrochemical behavior and coupling behavior with α(Al)in 3.5% NaCl solution were investigated.Meanwhile,the simulated Al alloy containing T1 particle was prepared and its corrosion morphology was observed.The results show that there exists a dynamic conversion corrosion mechanism associated with the precipitate of T1.At the beginning,the precipitate of T1 is anodic to the alloy base and corrosion occurs on its surface.However,during its corrosion process,its potential moves to a positive direction with immersion time increasing,due to the preferential dissolution of Li and the enrichment of Cu.As a result,the corroded T1 becomes cathodic to the alloy base at a later stage,leading to the anodic dissolution and corrosion of the alloy base at its adjacent periphery.It is suggested that the localized corrosion associated with the precipitate of T1 in Al-Li alloys is caused by the alternate anodic dissolution of the T1 precipitate and the alloy base at its adjacent periphery.展开更多
The behavior of growth and coarsening of T-1(Al2CuLi) precipitates was comparatively studied by means of TEM technique in two Al-Li alloys 2090 and 2090+Ce (with cerium content less than 0.1% in mass fraction). Statis...The behavior of growth and coarsening of T-1(Al2CuLi) precipitates was comparatively studied by means of TEM technique in two Al-Li alloys 2090 and 2090+Ce (with cerium content less than 0.1% in mass fraction). Statistical analysis results show that T-1 precipitates in alloy 2090+Ce have smaller aspect ratio, which is connected with the more intersections between different T-1 variants in this alloy. It is also found that the variation of maximum length of T-1 precipitates with aging time can be obviously divided into two stages of growth and coarsening. The diffusion coefficients of solute atoms of Cu and Li are calculated via growth kinetics curves of T-1 precipitates. The results show that the diffusion of atom Cu plays a more important role in the formation of T-1 precipitates.展开更多
The behavior of interaction between dislocation and T 1 plate was observed and analyzed by means of TEM technique in Al Li alloys of 2090 and 2090+Ce. The observation results show that the interaction between disloc...The behavior of interaction between dislocation and T 1 plate was observed and analyzed by means of TEM technique in Al Li alloys of 2090 and 2090+Ce. The observation results show that the interaction between dislocation and T 1 plate is a mix type of shearing and Orowan looping, and the physical models are established by theory of precipitates strengthening. The results of calculation illustrate that the contribution of T 1 plate is up 30%～60% to the overall critical resolved shear stress (CRSS). The role of T 1 plate is enhanced with aging time in the material aged 3～48 h at 190℃, but this enhancing effect becomes gentle on overaged condition. The strengthening effects of T 1 plate in 2090 and 2090+Ce alloys are little different on under aged condition, but the strengthening effects of T 1 precipitates in alloy 2090+Ce is little bigger than that of 2090 on overaged condition, especially the cutting mechanism is only considered. The difference between strengthening effects of matrix in two alloys is about 3.2 MPa on underaged condition and 8.7 MPa or so on overaged condition.展开更多
目的运用3.0T磁共振T2加权像(T2WI)判断APPswe/PSEN1dE9(APP/PS1)双转基因小鼠在miRNA-146a干预下的神经影像变化。方法使用GE Signa Excite HD 3.0T超导磁共振扫描仪对中期(12月龄)的APP/PS1双转基因小鼠(AD组)、mRNA-146a干预治疗后AP...目的运用3.0T磁共振T2加权像(T2WI)判断APPswe/PSEN1dE9(APP/PS1)双转基因小鼠在miRNA-146a干预下的神经影像变化。方法使用GE Signa Excite HD 3.0T超导磁共振扫描仪对中期(12月龄)的APP/PS1双转基因小鼠(AD组)、mRNA-146a干预治疗后APP/PS1双转基因小鼠(干预组)、相同背景非转基因野生型小鼠C57小鼠(正常组),每组5只,以及对应的3组晚期(18月龄)小鼠,每组4只,行T2WI冠状位扫描。应用GE Medical Systems Functool 4.4工作站软件进行图像后处理,测得1 mm2感兴趣区(ROI)下的海马与同侧肌肉的T2WI信号强度比值。采用方差分析比较中晚期各组小鼠的T2WI信号强度。结果与正常组比较,AD组小鼠显示的海马区散在点状T2WI低信号影增多,干预组小鼠海马区T2WI信号较相同月龄AD组的小鼠强。12、18月龄AD组小鼠的T2WI信号强度比值均比正常组降低(P<0.05或0.01);干预组的T2WI信号强度比值则高于AD组(P<0.01),与正常组比较差异无统计学意义(P>0.05)。中晚期各组小鼠的肌肉信号相对稳定,差异无统计学意义(P>0.05)。结论运用3.0T磁共振T2WI成像对海马区的T2信号强度比值进行对比分析,有助于判断APP/PS1双转基因小鼠的成模情况及其在miRNA-146a干预治疗下的疗效。展开更多
Amyotrophic lateral sclerosis （ALS） is a fatal progressive disorder characterized by the selective degeneration of motor neurons （MN）. The impact of peripheral immune status on disease progression and MN survival ...Amyotrophic lateral sclerosis （ALS） is a fatal progressive disorder characterized by the selective degeneration of motor neurons （MN）. The impact of peripheral immune status on disease progression and MN survival is becoming increasingly recognized in the ALS research field. In this review, we briefly discuss findings from mouse models of peripheral nerve injury and immunodeficiency to understand how the immune system regulates MN survival. We extend these observations to similar studies in the widely used superoxide dismutase 1 （SOD1） mouse model of ALS. Last, we present future hypotheses to identify potential causative factors that lead to immune dysregulation in ALS. The lessons from preceding work in this area offer new exciting directions to bridge the gap in our current understanding of immune mediated neuroprotection in ALS.展开更多
In a recent manuscript published in Cell,Liang et al.discovered novel ferroptosis regulators,membrane-bound O-acyltransferase domain-containing 1 and 2(MBOAT1/2).1 These findings may have implications for ferroptosis-...In a recent manuscript published in Cell,Liang et al.discovered novel ferroptosis regulators,membrane-bound O-acyltransferase domain-containing 1 and 2(MBOAT1/2).1 These findings may have implications for ferroptosis-based cancer therapy.展开更多
基金Project(50401012) supported by the National Natural Science Foundation of China
文摘To clarify the corrosion mechanism associated with the precipitate of T1(Al2CuLi)in Al-Li alloys,the simulated bulk precipitate of T1 was fabricated through melting and casting.Its electrochemical behavior and coupling behavior with α(Al)in 3.5% NaCl solution were investigated.Meanwhile,the simulated Al alloy containing T1 particle was prepared and its corrosion morphology was observed.The results show that there exists a dynamic conversion corrosion mechanism associated with the precipitate of T1.At the beginning,the precipitate of T1 is anodic to the alloy base and corrosion occurs on its surface.However,during its corrosion process,its potential moves to a positive direction with immersion time increasing,due to the preferential dissolution of Li and the enrichment of Cu.As a result,the corroded T1 becomes cathodic to the alloy base at a later stage,leading to the anodic dissolution and corrosion of the alloy base at its adjacent periphery.It is suggested that the localized corrosion associated with the precipitate of T1 in Al-Li alloys is caused by the alternate anodic dissolution of the T1 precipitate and the alloy base at its adjacent periphery.
文摘The behavior of growth and coarsening of T-1(Al2CuLi) precipitates was comparatively studied by means of TEM technique in two Al-Li alloys 2090 and 2090+Ce (with cerium content less than 0.1% in mass fraction). Statistical analysis results show that T-1 precipitates in alloy 2090+Ce have smaller aspect ratio, which is connected with the more intersections between different T-1 variants in this alloy. It is also found that the variation of maximum length of T-1 precipitates with aging time can be obviously divided into two stages of growth and coarsening. The diffusion coefficients of solute atoms of Cu and Li are calculated via growth kinetics curves of T-1 precipitates. The results show that the diffusion of atom Cu plays a more important role in the formation of T-1 precipitates.
文摘The behavior of interaction between dislocation and T 1 plate was observed and analyzed by means of TEM technique in Al Li alloys of 2090 and 2090+Ce. The observation results show that the interaction between dislocation and T 1 plate is a mix type of shearing and Orowan looping, and the physical models are established by theory of precipitates strengthening. The results of calculation illustrate that the contribution of T 1 plate is up 30%～60% to the overall critical resolved shear stress (CRSS). The role of T 1 plate is enhanced with aging time in the material aged 3～48 h at 190℃, but this enhancing effect becomes gentle on overaged condition. The strengthening effects of T 1 plate in 2090 and 2090+Ce alloys are little different on under aged condition, but the strengthening effects of T 1 precipitates in alloy 2090+Ce is little bigger than that of 2090 on overaged condition, especially the cutting mechanism is only considered. The difference between strengthening effects of matrix in two alloys is about 3.2 MPa on underaged condition and 8.7 MPa or so on overaged condition.
文摘目的运用3.0T磁共振T2加权像(T2WI)判断APPswe/PSEN1dE9(APP/PS1)双转基因小鼠在miRNA-146a干预下的神经影像变化。方法使用GE Signa Excite HD 3.0T超导磁共振扫描仪对中期(12月龄)的APP/PS1双转基因小鼠(AD组)、mRNA-146a干预治疗后APP/PS1双转基因小鼠(干预组)、相同背景非转基因野生型小鼠C57小鼠(正常组),每组5只,以及对应的3组晚期(18月龄)小鼠,每组4只,行T2WI冠状位扫描。应用GE Medical Systems Functool 4.4工作站软件进行图像后处理,测得1 mm2感兴趣区(ROI)下的海马与同侧肌肉的T2WI信号强度比值。采用方差分析比较中晚期各组小鼠的T2WI信号强度。结果与正常组比较,AD组小鼠显示的海马区散在点状T2WI低信号影增多,干预组小鼠海马区T2WI信号较相同月龄AD组的小鼠强。12、18月龄AD组小鼠的T2WI信号强度比值均比正常组降低(P<0.05或0.01);干预组的T2WI信号强度比值则高于AD组(P<0.01),与正常组比较差异无统计学意义(P>0.05)。中晚期各组小鼠的肌肉信号相对稳定,差异无统计学意义(P>0.05)。结论运用3.0T磁共振T2WI成像对海马区的T2信号强度比值进行对比分析,有助于判断APP/PS1双转基因小鼠的成模情况及其在miRNA-146a干预治疗下的疗效。
基金supported by grants from NIH/NINDS R01 funding NS40433
文摘Amyotrophic lateral sclerosis （ALS） is a fatal progressive disorder characterized by the selective degeneration of motor neurons （MN）. The impact of peripheral immune status on disease progression and MN survival is becoming increasingly recognized in the ALS research field. In this review, we briefly discuss findings from mouse models of peripheral nerve injury and immunodeficiency to understand how the immune system regulates MN survival. We extend these observations to similar studies in the widely used superoxide dismutase 1 （SOD1） mouse model of ALS. Last, we present future hypotheses to identify potential causative factors that lead to immune dysregulation in ALS. The lessons from preceding work in this area offer new exciting directions to bridge the gap in our current understanding of immune mediated neuroprotection in ALS.
文摘In a recent manuscript published in Cell,Liang et al.discovered novel ferroptosis regulators,membrane-bound O-acyltransferase domain-containing 1 and 2(MBOAT1/2).1 These findings may have implications for ferroptosis-based cancer therapy.
