Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loa...Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.展开更多
文摘目的研究急性缺血性脑卒中(acute ischemic stroke,AIS)患者的血清中糖蛋白非转移性黑色素瘤蛋白B(glycoprotein non-metastatic melanoma protein B,GPNMB)浓度和神经功能损伤程度以及预后的关系,筛选潜在生物标志物,为临床诊治提供参考。方法选择2023年6月至2024年3月在南通大学第二附属医院神经内科住院治疗的105例AIS患者作为样本群。入组患者按照入院24 h美国国立卫生研究院脑卒中量表(National Institutes of Health Strobe Scale,NIHSS)评分划分为轻度组(n=42)和中重度组(n=63),以改良Rankin量表(Modified Rankin Scale,mRS)评价出院后3个月功能恢复情况,将样本细分为预后良好组(n=34)和预后不良组(n=71),采用ELISA法检测血清GPNMB蛋白浓度,分析血清GPNMB蛋白浓度与NIHSS、mRS评分的相关性,并用二元Logistic回归模型评估血清GPNMB蛋白浓度对AIS神经功能损害的预测价值和预后评估价值。结果中重度神经功能损伤及预后不良患者血清GPNMB蛋白浓度明显低于轻度及预后良好组(P<0.05),血清GPNMB蛋白浓度与NIHSS评分呈显著负相关(r=-0.196,P<0.05),与mRS评分也呈显著负相关趋势(r=-0.334,P<0.05)。多变量回归分析显示,GPNMB依然是AIS的关键独立危险因素(P<0.05),根据受试者工作特征曲线得出的评估结果表明,血清GPNMB蛋白浓度在预测神经功能损伤以及不良预后方面的有诊断价值(灵敏度达到55.6%,特异度为81.8%,准确率是63.81%,P<0.05)。结论血清GPNMB蛋白浓度降低同AIS患者神经功能损害的程度存在明显的正相关联系,很有可能会成为衡量病情严重程度和长期转归情况的重要生物指标。
基金Project(50478075) supported by the National Natural Science Foundation of ChinaProject(YBJJ0817) supported by Scientific Research Foundation of Graduate School of Southeast University
文摘Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.
