Additive manufactured metals sometimes exhibit extraordinary microstructures and mechanical properties due to the particular processes. In this paper, we focus on a novel gradient TiAl alloys fabricated byhigh-power d...Additive manufactured metals sometimes exhibit extraordinary microstructures and mechanical properties due to the particular processes. In this paper, we focus on a novel gradient TiAl alloys fabricated byhigh-power direct laser deposition, whose chemical composition, microstructure, and mechanical property vary along the building direction. The results indicate that Al concentration dramatically decreasesfrom 39.5 at.% to 30.1 at.% as the height increases from the bottom to the top. Meanwhile, microstructural characterization indicates that the specimen appears basket-weave microstructure at the bottom,then the α_(2) and γ phase gradually decrease, and eventually it transforms into acicular martensite microstructure in the top region. The indentation analysis shows that the associated hardness increases asthe height increases, while the plasticity reaches a minimum value in the middle region. The increasingamount of β_(o)(ω) is considered to be responsible for the increasing hardness because of the strong precipitation strengthening effect. The high plasticity in the bottom and top regions results from the strongdeformation behaviors of the γ and β_(o) phases.展开更多
Background and Aims:Acute liver failure(ALF)is an inflammatory process of acute liver cell injury.Mesenchymal stem cells(MSCs)are undifferentiated,primitive cells with antiinflammatory,anti-apoptotic,and multi-directi...Background and Aims:Acute liver failure(ALF)is an inflammatory process of acute liver cell injury.Mesenchymal stem cells(MSCs)are undifferentiated,primitive cells with antiinflammatory,anti-apoptotic,and multi-directional differentiation abilities.This study aimed to explore the therapeutic mechanism of umbilical cord(U)MSCs in ALF.Methods:Dgalactosamine(D-GalN)combined with lipopolysaccharide(LPS)was used to establish an ALF model.After model establishment,UMSCs were injected via the tail vein.After UMSC transplantation,the number of mouse deaths was monitored every 12 h.A fully automatic biochemical analyzer was used to detect changes in biochemical analysis.Pathological changes was observed by stained with hematoxylin and eosin.The expression of My D88 was detected by immunohistochemical analysis,quantitative reverse transcription,and western blotting.The expression of NF-κB was detected by quantitative reverse transcription,western blotting.The expression of Bcl-2,Bax were detected by quantitative reverse transcription,western blotting.The expression of TNF-α,IL-1β,IL-6 were detected by enzyme-linked immunosorbent assay.Results:The 48-h survival rate of the UMSC-treated group was significantly higher than that of the LPS/D-GalNexposed group.After 24 h of LPS/D-GalN exposure,UMSCs reduced serum alanine aminotransferase and aspartate aminotransferase levels and improved the liver structure.Western blot and real-time fluorescence quantitative nucleic acid amplification analyses showed that UMSCs decreased MyD88 expression,thereby inhibiting LPS/GalN-induced phosphorylation and degradation of inhibitor of nuclear factor(NF)-κB(IκB).Additionally,NF-κB p65 underwent nuclear translocation,inhibiting the production of the inflammatory factors interleukin(IL)-1β,IL-6 and tumor necrosis factor(TNF)-αand played a protective role in ALF by down-regulating the pro-apoptotic gene Bax and up-regulating the anti-apoptotic gene Bcl-2.In summary,these findings indicate that UMSCs play a protective role in LPS/GalN-induced acute liver injury via inhibition of the MyD88 pathway and subsequent inhibition of NF-κB-mediated cytokine production.Conclusions:Through the above mechanisms,UMSCs can effectively reduce LPS/D-GalN-induced ALF,reduce mouse mortality,and restore damaged liver function and damaged liver tissue.展开更多
基金The authors acknowledge financial support from the National Natural Science Foundation of China(No.52101139 and No.51971145).
文摘Additive manufactured metals sometimes exhibit extraordinary microstructures and mechanical properties due to the particular processes. In this paper, we focus on a novel gradient TiAl alloys fabricated byhigh-power direct laser deposition, whose chemical composition, microstructure, and mechanical property vary along the building direction. The results indicate that Al concentration dramatically decreasesfrom 39.5 at.% to 30.1 at.% as the height increases from the bottom to the top. Meanwhile, microstructural characterization indicates that the specimen appears basket-weave microstructure at the bottom,then the α_(2) and γ phase gradually decrease, and eventually it transforms into acicular martensite microstructure in the top region. The indentation analysis shows that the associated hardness increases asthe height increases, while the plasticity reaches a minimum value in the middle region. The increasingamount of β_(o)(ω) is considered to be responsible for the increasing hardness because of the strong precipitation strengthening effect. The high plasticity in the bottom and top regions results from the strongdeformation behaviors of the γ and β_(o) phases.
基金This research was supported by the National Natural Science Foundation of China(Grant No.40117026).
文摘Background and Aims:Acute liver failure(ALF)is an inflammatory process of acute liver cell injury.Mesenchymal stem cells(MSCs)are undifferentiated,primitive cells with antiinflammatory,anti-apoptotic,and multi-directional differentiation abilities.This study aimed to explore the therapeutic mechanism of umbilical cord(U)MSCs in ALF.Methods:Dgalactosamine(D-GalN)combined with lipopolysaccharide(LPS)was used to establish an ALF model.After model establishment,UMSCs were injected via the tail vein.After UMSC transplantation,the number of mouse deaths was monitored every 12 h.A fully automatic biochemical analyzer was used to detect changes in biochemical analysis.Pathological changes was observed by stained with hematoxylin and eosin.The expression of My D88 was detected by immunohistochemical analysis,quantitative reverse transcription,and western blotting.The expression of NF-κB was detected by quantitative reverse transcription,western blotting.The expression of Bcl-2,Bax were detected by quantitative reverse transcription,western blotting.The expression of TNF-α,IL-1β,IL-6 were detected by enzyme-linked immunosorbent assay.Results:The 48-h survival rate of the UMSC-treated group was significantly higher than that of the LPS/D-GalNexposed group.After 24 h of LPS/D-GalN exposure,UMSCs reduced serum alanine aminotransferase and aspartate aminotransferase levels and improved the liver structure.Western blot and real-time fluorescence quantitative nucleic acid amplification analyses showed that UMSCs decreased MyD88 expression,thereby inhibiting LPS/GalN-induced phosphorylation and degradation of inhibitor of nuclear factor(NF)-κB(IκB).Additionally,NF-κB p65 underwent nuclear translocation,inhibiting the production of the inflammatory factors interleukin(IL)-1β,IL-6 and tumor necrosis factor(TNF)-αand played a protective role in ALF by down-regulating the pro-apoptotic gene Bax and up-regulating the anti-apoptotic gene Bcl-2.In summary,these findings indicate that UMSCs play a protective role in LPS/GalN-induced acute liver injury via inhibition of the MyD88 pathway and subsequent inhibition of NF-κB-mediated cytokine production.Conclusions:Through the above mechanisms,UMSCs can effectively reduce LPS/D-GalN-induced ALF,reduce mouse mortality,and restore damaged liver function and damaged liver tissue.
