Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space developmen...Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space development. Whilst the load-bearing of pipe-roof structures has been the subject of much research, uncertainties of deformation mechanism and the derivation of reliable calculation methods remain a challenge. For efficient design and wider deployment, this paper presents a bidirectional bending test to investigate the bending stiffnesses, load capacities and deformation mechanisms. The results show that the STS specimens exhibit good ductility and experience bending failure, and their deformation curves follow a half-sine wave upon loading. On this basis, the development of an STS composite slab deformation prediction model is proposed, along with the estimation for its bending stiffness. Theoretical predictions are shown to be in good agreement with the experimental measurements, with a maximum error of less than 15%. The outcomes of this investigation can provide references for the design and application of STS structures.展开更多
目的:探讨血红蛋白与血肌酐比值(hemoglobin to serum creatinine ratio,Hb/SCr)对ST段抬高型心肌梗死(STEMI)患者经皮冠状动脉介入治疗(PCI)术后3年全因死亡的预测价值。方法:回顾性选取2016年6月至2020年6月在甘肃省人民医院心血管内...目的:探讨血红蛋白与血肌酐比值(hemoglobin to serum creatinine ratio,Hb/SCr)对ST段抬高型心肌梗死(STEMI)患者经皮冠状动脉介入治疗(PCI)术后3年全因死亡的预测价值。方法:回顾性选取2016年6月至2020年6月在甘肃省人民医院心血管内科成功完成首次PCI的STEMI患者687例,根据术后3年内生存情况分为生存组和死亡组。采用Cox回归分析STEMI患者发生全因死亡的影响因素,绘制受试者工作特征(ROC)曲线评估Hb/SCr对STEMI患者PCI术后全因死亡的预测价值,并通过Kaplan-Meier生存曲线比较不同水平Hb/SCr的STEMI患者随访过程中累积生存率的差异。结果:共663例(96.51%)成功完成随访,中位随访37(25,50)个月期间,41例(6.18%)发生全因死亡。多因素Cox回归分析结果显示,年龄(HR=1.086,95%CI:1.037~1.137,P=0.000),体重指数(HR=1.195,95%CI:1.128~1.266,P=0.000),空腹血糖(HR=1.069,95%CI:1.007~1.135,P=0.030),纤维蛋白原(HR=1.418,95%CI:1.120~1.795,P=0.004),心肌梗死溶栓治疗临床试验(TIMI)血流分级1级(HR=4.968,95%CI:1.194~20.667,P=0.028)、2级(HR=3.861,95%CI:1.336~11.156,P=0.013),Hb/SCr(HR=0.858,95%CI:0.766~0.961,P=0.008)为STEMI患者PCI术后3年全因死亡的独立影响因素。ROC曲线分析结果显示,Hb/SCr诊断PCI术后全因死亡的曲线下面积为0.721(95%CI:0.645~0.798),灵敏度为65.9%,特异度为71.2%,最佳截断值为16.627。Kaplan-Meier生存曲线分析结果显示,Hb/SCr<16.627的患者生存率明显低于Hb/SCr≥16.627的患者(log-rank P=0.000)。结论:Hb/SCr是STEMI患者PCI术后3年全因死亡的独立影响因素,且对全因死亡具有一定预测价值。展开更多
基金Project(BK20210721) supported by the Natural Science Foundation of Jiangsu Province,ChinaProjects(52108380,52078506) supported by the National Natural Science Foundation of ChinaProject(2023A1515012159) supported by the Guangdong Basic and Applied Basic Research Foundation,China。
文摘Steel tube slab (STS) structure, a novel pipe-roof structure, of which steel tubes are connected with flange plates, bolts and concrete, is an increasingly popular supporting structure for underground space development. Whilst the load-bearing of pipe-roof structures has been the subject of much research, uncertainties of deformation mechanism and the derivation of reliable calculation methods remain a challenge. For efficient design and wider deployment, this paper presents a bidirectional bending test to investigate the bending stiffnesses, load capacities and deformation mechanisms. The results show that the STS specimens exhibit good ductility and experience bending failure, and their deformation curves follow a half-sine wave upon loading. On this basis, the development of an STS composite slab deformation prediction model is proposed, along with the estimation for its bending stiffness. Theoretical predictions are shown to be in good agreement with the experimental measurements, with a maximum error of less than 15%. The outcomes of this investigation can provide references for the design and application of STS structures.
