The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning tra...The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy,energy-dispersive X-ray spectroscopy and first-principles cal-culations.The heat treatment initially produces a pure L1_(2)-Al_(3)Zr microstructure,allowing for about 13%Cu to be incorporated in the dispersoid.Cu incorporation increases the energy barrier for anti-phase boundary(APB)activation,thus stabilizing the L1_(2)structure.Additional heating leads to a Cu-induced“branched”path for the L1_(2)structural transformation,with the latter process accelerated once the first APB has been created.Cu atoms may either(i)be repelled by the APBs,promoting the transformation to a Cu-poor D0_(23) phase,or(ii)they may segregate at one Al-Zr layer adjacent to the APB,promoting a transformation to a new thermodynamically favored phase,Al4 CuZr,formed when these segregation layers are periodically arranged.Theoretical studies suggest that the branching of the L1_(2)transformation path is linked to the speed at which an APB is created,with Cu attraction triggered by a comparatively slow process.This unexpected transformation behavior of the L1_(2)-Al_(3)Zr phase opens a new path to un-derstanding,and potentially regulating the Al_(3)Zr dispersoid evolution for high temperature applications.展开更多
Emerging evidence that Enterovirus A 71(EV-A71)infection closely related to apoptosis.The ZVAD is a caspase inhibitor that can prevent apoptosis.The aims of this project were to evaluate the mechanism of the ZVAD inhi...Emerging evidence that Enterovirus A 71(EV-A71)infection closely related to apoptosis.The ZVAD is a caspase inhibitor that can prevent apoptosis.The aims of this project were to evaluate the mechanism of the ZVAD inhibited EV-A71 virus and to provide experiment basis for finding new antiviral drugs.In this study,after treated with ZVAD in EV-A71 infected Vero cells,the viral replication was reduced,and the cell viability was higher than EV-A71 group.Additionally,ZVAD decreased the cell apoptosis and the level of inflammatory cytokines induced by EV-A71 in the infected Vero cells.ZVAD inhibited cell apoptosis by regulating ROS mediated signaling pathway and inflammation cytokines to achieve antiviral.展开更多
Fretting damage is common in the high-strength titanium alloy fastener widely used in the aeronautic industry,leading to the failure of fastening fit or the initiation of crack.The titanium alloy fasteners often have ...Fretting damage is common in the high-strength titanium alloy fastener widely used in the aeronautic industry,leading to the failure of fastening fit or the initiation of crack.The titanium alloy fasteners often have typical preferred orientation characteristics(i.e.,texture),and this is one of the important factors affecting its performance.However,the investigations on the mechanism ofβrolling-texture intensity on fretting damage resistance and subsurface deformation are less addressed.Hence,fretting wear tests were carried out on samples with different rolling texture intensities.The results demonstrate that the samples with quite low(A-10%sample)and quite high(D-70%sample)rolling-texture intensity both exhibit excellent fretting wear resistance,but their mechanisms are completely different.Uniformly dispersed grain orientation renders the A-10%sample with good recovery ability and a positive friction effect during wear.Low stress only concentrating at grain boundaries(GBs)weakens cracks’initiation and propagation.The unique orientation-layered structure(OLS)leads to excellent recovery ability and a positive friction effect.Crack propagation is inhibited and only propagates along the OLS boundary without a connected trend.However,samples with moderate rolling texture intensity exhibit severe wear.Dislocations are restricted in local areas,so the poor recovery ability makes them have a negative friction effect.Crack propagation driving force continuously increases.Appropriate rolling texture intensity can reduce wear by three times.This study can provide information on the principle for designing fretting damage-resistant alloys.展开更多
RNA interference(RNAi)is one of the most promising methods for the treatment of malignant tumors.However,developing an efficient biocompatible delivery vector for small interfering RNA(siRNA)remains a challenging issu...RNA interference(RNAi)is one of the most promising methods for the treatment of malignant tumors.However,developing an efficient biocompatible delivery vector for small interfering RNA(siRNA)remains a challenging issue.This study aimed to prepare a non-viral tumor-targeted carrier,named RGDfC-modified functionalized selenium nanoparticles(RGDfC-SeNPs).RGDfC-SeNPs were used to selectively deliver siSox2 to HepG2 liver cancer cells and tissues for the treatment of hepatocellular carcinoma(HCC).In the current study,RGDfC-SeNPs were successfully synthesized and characterized.It was shown that RGDfC-SeNPs could effectively load siSox2 to prepare an antitumor prodrug RGDfC-Se@siSox2.RGDfC-Se@siSox2 exhibited selective uptake in HepG2 liver cancer cells and LO2 normal liver cells,indicating RGDfC-SeNPs could effectively deliver siSox2 to HepG2 liver cancer cells.RGDfC-Se@siSox2 entered HepG2 cells via clathrin-mediated endocytosis by firstly encircling the cytoplasm and then releasing siSox2 in the lysosomes.RGDfC-Se@siSox2 could effectively silence Sox2 and inhibit the proliferation,migration and invasion of HepG2 cells.RGDfC-Se@siSox2 induced HepG2 cells apoptosis most likely via overproduction of reactive oxygen species and disruption of the mitochondrial membrane potentials.Most importantly,RGDfC-Se@siSox2 significantly inhibited the tumor growth in HepG2 tumor-bearing mice without obvious toxic side effects.These studies indicated that RGDfC-SeNPs may be an ideal gene carrier for delivering siSox2 to HepG2 cells and that RGDfC-Se@siSox2 may be a novel and highly specific gene-targeted prodrug therapy for HCC.展开更多
基金supported by the National Key Research and Development Program(No.2020YFA0405900)the National Natural Science Foundation of China(Grant No.52371111 and U2141215)the Natural Science Foundation of Jiangsu Province(No.BE2022159).
文摘The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy,energy-dispersive X-ray spectroscopy and first-principles cal-culations.The heat treatment initially produces a pure L1_(2)-Al_(3)Zr microstructure,allowing for about 13%Cu to be incorporated in the dispersoid.Cu incorporation increases the energy barrier for anti-phase boundary(APB)activation,thus stabilizing the L1_(2)structure.Additional heating leads to a Cu-induced“branched”path for the L1_(2)structural transformation,with the latter process accelerated once the first APB has been created.Cu atoms may either(i)be repelled by the APBs,promoting the transformation to a Cu-poor D0_(23) phase,or(ii)they may segregate at one Al-Zr layer adjacent to the APB,promoting a transformation to a new thermodynamically favored phase,Al4 CuZr,formed when these segregation layers are periodically arranged.Theoretical studies suggest that the branching of the L1_(2)transformation path is linked to the speed at which an APB is created,with Cu attraction triggered by a comparatively slow process.This unexpected transformation behavior of the L1_(2)-Al_(3)Zr phase opens a new path to un-derstanding,and potentially regulating the Al_(3)Zr dispersoid evolution for high temperature applications.
基金supported by the fund from Open Project of Guangdong Key Laboratory of Marine Materia Medica(LMM2020-7)the fund from Guangzhou Institute of Pediatrics/Guangzhou Women and Children’s Medical Center(Nos.Pre-NSFC-2019-016,YIP-2019-059,IP-2019-019)+3 种基金the Project of Traditional Chinese Medicine Bureau of Guangdong Province(No.20192075)the technology planning projects of Guangdong province(No.202102010202)The Guangdong Natural Science Foundation(2020A1515110648)the Open Fund of Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications(2020A03).
文摘Emerging evidence that Enterovirus A 71(EV-A71)infection closely related to apoptosis.The ZVAD is a caspase inhibitor that can prevent apoptosis.The aims of this project were to evaluate the mechanism of the ZVAD inhibited EV-A71 virus and to provide experiment basis for finding new antiviral drugs.In this study,after treated with ZVAD in EV-A71 infected Vero cells,the viral replication was reduced,and the cell viability was higher than EV-A71 group.Additionally,ZVAD decreased the cell apoptosis and the level of inflammatory cytokines induced by EV-A71 in the infected Vero cells.ZVAD inhibited cell apoptosis by regulating ROS mediated signaling pathway and inflammation cytokines to achieve antiviral.
基金supported by the National Natural Science Foun-dation of China(No.52105211)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2023-TS-04)the Fundamental Research Funds for the Central Universi-ties of China(No.3102019JC001).
文摘Fretting damage is common in the high-strength titanium alloy fastener widely used in the aeronautic industry,leading to the failure of fastening fit or the initiation of crack.The titanium alloy fasteners often have typical preferred orientation characteristics(i.e.,texture),and this is one of the important factors affecting its performance.However,the investigations on the mechanism ofβrolling-texture intensity on fretting damage resistance and subsurface deformation are less addressed.Hence,fretting wear tests were carried out on samples with different rolling texture intensities.The results demonstrate that the samples with quite low(A-10%sample)and quite high(D-70%sample)rolling-texture intensity both exhibit excellent fretting wear resistance,but their mechanisms are completely different.Uniformly dispersed grain orientation renders the A-10%sample with good recovery ability and a positive friction effect during wear.Low stress only concentrating at grain boundaries(GBs)weakens cracks’initiation and propagation.The unique orientation-layered structure(OLS)leads to excellent recovery ability and a positive friction effect.Crack propagation is inhibited and only propagates along the OLS boundary without a connected trend.However,samples with moderate rolling texture intensity exhibit severe wear.Dislocations are restricted in local areas,so the poor recovery ability makes them have a negative friction effect.Crack propagation driving force continuously increases.Appropriate rolling texture intensity can reduce wear by three times.This study can provide information on the principle for designing fretting damage-resistant alloys.
基金supported by National Natural Science Foundation of China(81970507)Natural Science Foundation of Guangdong Province(2020A1515010100)+3 种基金Technology Planning Project of Guangzhou City(201904010132)Innovative Clinical Technique of Guangzhou(2019GX05)China Postdoctoral Science Foundation(2017M612632)Yu Xia thanks to Yuyan Huang and all the staff of Guangzhou First People’s Hospital for supporting this research.
文摘RNA interference(RNAi)is one of the most promising methods for the treatment of malignant tumors.However,developing an efficient biocompatible delivery vector for small interfering RNA(siRNA)remains a challenging issue.This study aimed to prepare a non-viral tumor-targeted carrier,named RGDfC-modified functionalized selenium nanoparticles(RGDfC-SeNPs).RGDfC-SeNPs were used to selectively deliver siSox2 to HepG2 liver cancer cells and tissues for the treatment of hepatocellular carcinoma(HCC).In the current study,RGDfC-SeNPs were successfully synthesized and characterized.It was shown that RGDfC-SeNPs could effectively load siSox2 to prepare an antitumor prodrug RGDfC-Se@siSox2.RGDfC-Se@siSox2 exhibited selective uptake in HepG2 liver cancer cells and LO2 normal liver cells,indicating RGDfC-SeNPs could effectively deliver siSox2 to HepG2 liver cancer cells.RGDfC-Se@siSox2 entered HepG2 cells via clathrin-mediated endocytosis by firstly encircling the cytoplasm and then releasing siSox2 in the lysosomes.RGDfC-Se@siSox2 could effectively silence Sox2 and inhibit the proliferation,migration and invasion of HepG2 cells.RGDfC-Se@siSox2 induced HepG2 cells apoptosis most likely via overproduction of reactive oxygen species and disruption of the mitochondrial membrane potentials.Most importantly,RGDfC-Se@siSox2 significantly inhibited the tumor growth in HepG2 tumor-bearing mice without obvious toxic side effects.These studies indicated that RGDfC-SeNPs may be an ideal gene carrier for delivering siSox2 to HepG2 cells and that RGDfC-Se@siSox2 may be a novel and highly specific gene-targeted prodrug therapy for HCC.
