Electron beam selective melting(EBM)and selective laser melting(SLM)are regarded as significant manufacturing processes for near-net-shaped Ti6Al4V components.Generally,in the conventional EBM process,preheating is ne...Electron beam selective melting(EBM)and selective laser melting(SLM)are regarded as significant manufacturing processes for near-net-shaped Ti6Al4V components.Generally,in the conventional EBM process,preheating is necessitated to avoid"smoke"caused by the charging of electrons.In the conventional SLM process,laser as an energy source without the risk of"smoke"can be employed to melt metal powder at low temperatures.However,because of the low absorption rate of laser,the powder bed temperature cannot reach a high level.It is difficult to obtain as-built TiAl4V with favorable comprehensive properties via conventional EBM or SLM.Hence,two types of electron beam and laser hybrid preheating(EB-LHP)combined with selective melting strategies are proposed.Using laser to preheat powder allows EBM to be performed at a low powder bed temperature(EBM-LT),whereas using an electron beam to preheat powder allows SLM to be performed at a high powder bed temperature(SLM-HT).Ti6Al4V samples are fabricated using two different manufacturing strategies(i.e.,EBM-LT and SLM-HT)and two conventional processes,i.e.,EBM at a high powder bed temperature(EBM-HT)and SLM at a low powder bed temperature(SLM-LT).The temperature-dependent surface quality,microstructure,density,and mechanical properties of the as-built Ti6Al4V samples are characterized and compared.Results show that EBM-LT Ti6Al4V exhibits a higher ultimate tensile strength(981±43 MPa)and a lower elongation(12.2%±2.3%)than EBM-HT Ti6Al4V owing to the presence ofα′martensite.The SLM-HT Ti6Al4V possesses the highest ultimate tensile strength(1,059±62 MPa)and an elongation(14.8%±4.0%)comparable to that of the EBM-HT Ti6Al4V(16.6%±1.2%).展开更多
BACKGROUND Pyroptosis is an inflammatory form of programmed cell death,which has been shown to be related to the prognosis of many tumors.However,its role in gastric cancer(GC)is not fully understood.AIM To evaluate t...BACKGROUND Pyroptosis is an inflammatory form of programmed cell death,which has been shown to be related to the prognosis of many tumors.However,its role in gastric cancer(GC)is not fully understood.AIM To evaluate the expression of pyroptosis-related genes in GC and its correlation with prognosis.METHODS We constructed prognostic multigene markers of differentially expressed genes associated with pyroptosis by least absolute contraction and selection operator Cox regression.The risk model was analyzed by Kaplan-Meier curve,two-sided log-rank test and functional enrichment analysis.RESULTS Sixty-three pyroptosis-related genes were differentially expressed in tumor tissues and adjacent nontumor tissues.Based on these differentially expressed genes,5 gene signature were constructed and all GC patients were classified into two risk groups.Kaplan-Meier survival curve showed that the overall survival(OS)of patients in the high-risk group was significantly lower than that of the low-risk group.Multivariate Cox regression analyses showed that the risk score was an independent risk factor for OS.Receiver operating characteristic curve analysis confirmed the predictive ability of the model.External validation indicated increased OS in the low-risk group.The immune function and immune cell scores of the high-risk group were generally higher than those of the low-risk group.CONCLUSION Pyroptosis-related genes play a significant role in tumor immune microenvironment.This novel model,which contains 5 pyroptosis-related genes,is an independent predicting factor for OS in GC patients,and may help to evaluate the prognosis of GC.展开更多
基金the National Key R&D Program(2018YFB1105200)111 Project(B17026)Open Fund of State Key Laboratory of Advanced Forming Technology and Equipment(SKL2019006)。
文摘Electron beam selective melting(EBM)and selective laser melting(SLM)are regarded as significant manufacturing processes for near-net-shaped Ti6Al4V components.Generally,in the conventional EBM process,preheating is necessitated to avoid"smoke"caused by the charging of electrons.In the conventional SLM process,laser as an energy source without the risk of"smoke"can be employed to melt metal powder at low temperatures.However,because of the low absorption rate of laser,the powder bed temperature cannot reach a high level.It is difficult to obtain as-built TiAl4V with favorable comprehensive properties via conventional EBM or SLM.Hence,two types of electron beam and laser hybrid preheating(EB-LHP)combined with selective melting strategies are proposed.Using laser to preheat powder allows EBM to be performed at a low powder bed temperature(EBM-LT),whereas using an electron beam to preheat powder allows SLM to be performed at a high powder bed temperature(SLM-HT).Ti6Al4V samples are fabricated using two different manufacturing strategies(i.e.,EBM-LT and SLM-HT)and two conventional processes,i.e.,EBM at a high powder bed temperature(EBM-HT)and SLM at a low powder bed temperature(SLM-LT).The temperature-dependent surface quality,microstructure,density,and mechanical properties of the as-built Ti6Al4V samples are characterized and compared.Results show that EBM-LT Ti6Al4V exhibits a higher ultimate tensile strength(981±43 MPa)and a lower elongation(12.2%±2.3%)than EBM-HT Ti6Al4V owing to the presence ofα′martensite.The SLM-HT Ti6Al4V possesses the highest ultimate tensile strength(1,059±62 MPa)and an elongation(14.8%±4.0%)comparable to that of the EBM-HT Ti6Al4V(16.6%±1.2%).
文摘BACKGROUND Pyroptosis is an inflammatory form of programmed cell death,which has been shown to be related to the prognosis of many tumors.However,its role in gastric cancer(GC)is not fully understood.AIM To evaluate the expression of pyroptosis-related genes in GC and its correlation with prognosis.METHODS We constructed prognostic multigene markers of differentially expressed genes associated with pyroptosis by least absolute contraction and selection operator Cox regression.The risk model was analyzed by Kaplan-Meier curve,two-sided log-rank test and functional enrichment analysis.RESULTS Sixty-three pyroptosis-related genes were differentially expressed in tumor tissues and adjacent nontumor tissues.Based on these differentially expressed genes,5 gene signature were constructed and all GC patients were classified into two risk groups.Kaplan-Meier survival curve showed that the overall survival(OS)of patients in the high-risk group was significantly lower than that of the low-risk group.Multivariate Cox regression analyses showed that the risk score was an independent risk factor for OS.Receiver operating characteristic curve analysis confirmed the predictive ability of the model.External validation indicated increased OS in the low-risk group.The immune function and immune cell scores of the high-risk group were generally higher than those of the low-risk group.CONCLUSION Pyroptosis-related genes play a significant role in tumor immune microenvironment.This novel model,which contains 5 pyroptosis-related genes,is an independent predicting factor for OS in GC patients,and may help to evaluate the prognosis of GC.
