In this study,finite element(FE)analysis is utilized to investigate the shear capacity of reinforced concrete(RC)beams strengthened with embedded through-section(ETS)bars.Effects of critical variables on the beam shea...In this study,finite element(FE)analysis is utilized to investigate the shear capacity of reinforced concrete(RC)beams strengthened with embedded through-section(ETS)bars.Effects of critical variables on the beam shear strength,including the compressive strength of concrete,stiffness ratio between ETS bars and steel stirrups,and use of ETS strengthening system alone,are parametrically investigated.A promising method based on the bond mechanism between ETS strengthening and concrete is then proposed for predicting the shear resistance forces of the strengthened beams.An expression for the maximum bond stress of the ETS bars to concrete is developed.This new expression eliminates the difficulty in the search and selection of appropriate bond parameters from adhesion tests.The results obtained from the FE models and analytical models are validated by comparison with those measured from the experiments.Consequently,the model proposed in this study demonstrates better performance and more accuracy for prediction of the beam shear-carrying capacity than those of existing models.The results obtained from this study can also serve researchers and engineers in selection of the proper shear strength models for design of ETS-strengthened RC beams.展开更多
目的分析气腔播散(spread through air spaces,STAS)阳性对肺叶切除或亚肺叶切除Ⅰ~Ⅲ期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者预后的影响,同时探究冰冻切片指导STAS潜在阳性患者切除术式的可靠性。方法计算机检索PubMed...目的分析气腔播散(spread through air spaces,STAS)阳性对肺叶切除或亚肺叶切除Ⅰ~Ⅲ期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者预后的影响,同时探究冰冻切片指导STAS潜在阳性患者切除术式的可靠性。方法计算机检索PubMed、EMbase、The Cochrane Library、Web of Science数据库,纳入不同手术方式与STAS阳性Ⅰ~Ⅲ期NSCLC患者预后关系的研究,以及研究通过冰冻切片识别STAS准确度的文献,检索时限为建库至2022年7月。两位研究员独立检索、筛选、评价文献和提取资料。采用RevMan 5.4和STATA15.0进行统计学分析。使用纽卡斯尔-渥太华量表(Newcastle-Ottawa Scale,NOS)对研究进行质量评价。结果纳入26篇STAS相关文献,涉及手术的文献23篇(共12266例患者),其中11篇直接比较了肺叶切除和亚肺叶切除对STAS阳性患者术后生存的影响。NOS评分≥6分。Meta分析显示,STAS阳性为Ⅰ~Ⅲ期NSCLC患者肺叶切除和亚肺叶切除术后预后不利因素[无复发生存期(recurrence-free survival,RFS):HR=2.27,95%CI(1.96,2.63),P<0.01;总生存期(overall survival,OS):HR=2.08,95%CI(1.74,2.49),P<0.01],而在STAS阳性患者中,肺叶切除相比亚肺叶切除可带来更大的生存获益[RFS:HR=1.97,95%CI(1.59,2.44),P<0.01;OS:HR=1.91,95%CI(1.47,2.48),P<0.01]。在纳入4篇探究术中冰冻切片识别STAS准确性的研究后,灵敏度合并值为55%[95%CI(45%,64%)],特异度合并值为92%[95%CI(77%,97%)],而合并后曲线下面积为0.68[95%CI(0.64,0.72)]。结论本研究证实STAS阳性是早期NSCLC患者预后的重要危险因素之一,且STAS阳性患者肺叶切除相比亚肺叶切除可带来更大的生存获益,因此当术中快速冰冻提示STAS阳性时,应首选肺叶切除作为根治术式。术中冰冻切片识别STAS的特异度较高,可对术中术式的选择提供一定的参考,但由于其敏感性及准确性较低,还需要探索其他更为灵敏的检测方式以指导外科决策。展开更多
文摘In this study,finite element(FE)analysis is utilized to investigate the shear capacity of reinforced concrete(RC)beams strengthened with embedded through-section(ETS)bars.Effects of critical variables on the beam shear strength,including the compressive strength of concrete,stiffness ratio between ETS bars and steel stirrups,and use of ETS strengthening system alone,are parametrically investigated.A promising method based on the bond mechanism between ETS strengthening and concrete is then proposed for predicting the shear resistance forces of the strengthened beams.An expression for the maximum bond stress of the ETS bars to concrete is developed.This new expression eliminates the difficulty in the search and selection of appropriate bond parameters from adhesion tests.The results obtained from the FE models and analytical models are validated by comparison with those measured from the experiments.Consequently,the model proposed in this study demonstrates better performance and more accuracy for prediction of the beam shear-carrying capacity than those of existing models.The results obtained from this study can also serve researchers and engineers in selection of the proper shear strength models for design of ETS-strengthened RC beams.
文摘目的分析气腔播散(spread through air spaces,STAS)阳性对肺叶切除或亚肺叶切除Ⅰ~Ⅲ期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者预后的影响,同时探究冰冻切片指导STAS潜在阳性患者切除术式的可靠性。方法计算机检索PubMed、EMbase、The Cochrane Library、Web of Science数据库,纳入不同手术方式与STAS阳性Ⅰ~Ⅲ期NSCLC患者预后关系的研究,以及研究通过冰冻切片识别STAS准确度的文献,检索时限为建库至2022年7月。两位研究员独立检索、筛选、评价文献和提取资料。采用RevMan 5.4和STATA15.0进行统计学分析。使用纽卡斯尔-渥太华量表(Newcastle-Ottawa Scale,NOS)对研究进行质量评价。结果纳入26篇STAS相关文献,涉及手术的文献23篇(共12266例患者),其中11篇直接比较了肺叶切除和亚肺叶切除对STAS阳性患者术后生存的影响。NOS评分≥6分。Meta分析显示,STAS阳性为Ⅰ~Ⅲ期NSCLC患者肺叶切除和亚肺叶切除术后预后不利因素[无复发生存期(recurrence-free survival,RFS):HR=2.27,95%CI(1.96,2.63),P<0.01;总生存期(overall survival,OS):HR=2.08,95%CI(1.74,2.49),P<0.01],而在STAS阳性患者中,肺叶切除相比亚肺叶切除可带来更大的生存获益[RFS:HR=1.97,95%CI(1.59,2.44),P<0.01;OS:HR=1.91,95%CI(1.47,2.48),P<0.01]。在纳入4篇探究术中冰冻切片识别STAS准确性的研究后,灵敏度合并值为55%[95%CI(45%,64%)],特异度合并值为92%[95%CI(77%,97%)],而合并后曲线下面积为0.68[95%CI(0.64,0.72)]。结论本研究证实STAS阳性是早期NSCLC患者预后的重要危险因素之一,且STAS阳性患者肺叶切除相比亚肺叶切除可带来更大的生存获益,因此当术中快速冰冻提示STAS阳性时,应首选肺叶切除作为根治术式。术中冰冻切片识别STAS的特异度较高,可对术中术式的选择提供一定的参考,但由于其敏感性及准确性较低,还需要探索其他更为灵敏的检测方式以指导外科决策。
