目的探讨纤维细胞生长因子2(FGF-2)、微小RNA-206(miR-206)预测闭合性胫骨干骨折术后延迟愈合的价值。方法回顾性分析陆军第八十集团军医院2018年5月至2021年5月行闭合性胫骨干骨折手术的患者136例的临床资料,将术后延迟愈合的患者86例...目的探讨纤维细胞生长因子2(FGF-2)、微小RNA-206(miR-206)预测闭合性胫骨干骨折术后延迟愈合的价值。方法回顾性分析陆军第八十集团军医院2018年5月至2021年5月行闭合性胫骨干骨折手术的患者136例的临床资料,将术后延迟愈合的患者86例作为观察组,术后正常愈合患者50例为对照组。采用酶联免疫吸附法检测患者血清FGF-2水平,采用实时荧光聚合酶链式反应法检测血清miR-206水平,分析FGF-2、miR-206水平与闭合性胫骨干骨折术后延迟愈合的关系。结果观察组术后1 d、术后1周、术后4周血清FGF-2水平均显著低于对照组[(14.24±2.15)ng/L比(20.36±3.42)ng/L,(21.38±3.27)ng/L比(30.45±4.29)ng/L,(23.59±4.36)ng/L比(36.67±4.51)ng/L](t=7.42、8.42、16.66,均P<0.001),且其水平随着时间推移而逐渐升高;观察组术后1 d miR-206表达量低于对照组(t=7.50,P<0.001),而术后4周miR-206表达量高于对照组(t=17.24,P<0.001),术后1周两组miR-206表达量差异无统计学意义(P>0.05)。单因素分析结果显示,术后感染、FGF-2、miR-206与闭合性胫骨干骨折术后延迟愈合密切相关(均P<0.05)。多因素logistic回归分析结果显示,术后感染(OR=1.93,95%CI:1.20~3.07)、FGF-2(OR=2.10,95%CI:1.31~3.36)、miR-206(OR=2.30,95%CI:1.35~3.89)是影响闭合性胫骨干骨折术后延迟愈合的独立危险因素(均P<0.05)。根据骨折术后延迟愈合患者血清FGF-2、miR-206水平绘制受试者工作特征(ROC)曲线,结果显示,术后4周时FGF-2以29.83 ng/L为最佳截断值时,预测闭合性胫骨干骨折术后延迟愈合的曲线下面积为0.76(95%CI:1.23~3.25),灵敏度、特异度分别为79.34%、68.82%;术后4周时miR-206以0.63为最佳截断值时,预测闭合性胫骨干骨折术后延迟愈合的曲线下面积为0.72(95%CI:1.10~2.45),灵敏度、特异度分别为75.33%、67.25%;两者联合检测预测闭合性胫骨干骨折术后延迟愈合的曲线下面积为0.81(95%CI:1.35~3.26),灵敏度、特异度分别为展开更多
The simplification of fatigue load spectrum,which can effectively reduce experimental cost,is of great importance for structural fatigue tests.By introducing random variables,the probabilistic tolerance method of remo...The simplification of fatigue load spectrum,which can effectively reduce experimental cost,is of great importance for structural fatigue tests.By introducing random variables,the probabilistic tolerance method of removing small amplitude cycles proposed in this paper takes into account the randomness of both load and fatigue limit.The probability of the damage occurrence caused by the removed small loads is calculated to ensure that it cannot exceed the given probabilistic tolerance.Accordingly,the omission level is obtained and the truncated spectrum is formed.The unnotched aluminum sheet specimens are used to perform the fatigue test on the original fatigue spectrum and truncated fatigue spectrum of a transporter.The test results show that there is no statistical difference between the test life of the truncated spectrum and that of the original spectrum,which demonstrates the validity of the small-load-omitting method that considers randomness.展开更多
为提高哈希算法的感知性与鲁棒性,提出一种基于块截断编码与邻域空间LBP算子的鲁棒图像哈希算法。将预处理图像分割为非重叠子块,结合奇异值分解SVD(singular value decomposition),获取二次图像,引入块截断编码机制,输出其高、低电平...为提高哈希算法的感知性与鲁棒性,提出一种基于块截断编码与邻域空间LBP算子的鲁棒图像哈希算法。将预处理图像分割为非重叠子块,结合奇异值分解SVD(singular value decomposition),获取二次图像,引入块截断编码机制,输出其高、低电平矩和二进制位图;基于LBP(local binary pattern)算子,设计邻域空间LBP模式,获取位图的特征矩阵;构造量化函数,得到高、低电平矩阵对应的紧凑二值序列,利用主成分分析处理特征矩阵,输出二值序列,组合这些二值序列,获取图像哈希。根据Hamming距离,对图像真伪进行认证。实验数据表明,与当前哈希算法相比,所提哈希算法具有更好的抗碰撞性能与感知鲁棒。展开更多
为快速进行模型的降阶,结合平衡截断(Balanced Truncation,BT)方法和特征正交分解(Proper Orthogonal Decomposition,POD)方法提出一种模型降阶方法.该方法采用频域POD快照矩阵低阶逼近系统的可控、可观Gram矩阵;通过奇异值分解(Singula...为快速进行模型的降阶,结合平衡截断(Balanced Truncation,BT)方法和特征正交分解(Proper Orthogonal Decomposition,POD)方法提出一种模型降阶方法.该方法采用频域POD快照矩阵低阶逼近系统的可控、可观Gram矩阵;通过奇异值分解(Singular Value Decomposition,SVD)提取BT+POD模态,对低能量模态截断形成降阶子空间,并将其映射到全阶系统,从而形成基于状态空间的降阶模型(Reduced Order Model,ROM);该模型就成为全阶模型(Full Order Model,FOM)的ROM.通过对阶数n=406的LTI SISO系统和阶数n=9的2区间电力系统进行的验证表明,在保留BT方法输入输出平衡特性的基础上,该方法效率高于BT方法.展开更多
A family of symmetric (hybrid) two step sixth P-stable methods for the accurate numerical integration of second order periodic initial value problems have been considered in this paper. These methods, which require on...A family of symmetric (hybrid) two step sixth P-stable methods for the accurate numerical integration of second order periodic initial value problems have been considered in this paper. These methods, which require only three (new) function evaluation per iteration and per step integration. These methods have minimal local truncation error (LTE) and smaller phase-lag of sixth order than some sixth orders P-stable methods in [1-3,10-11]. The theoretical and numerical results show that these methods in this paper are more accurate and efficient than some methods proposed in [1-3,10].展开更多
In this paper, two families of high accuracy explicit two-step methods with minimal phase-lag are developed for the numerical integration of special secondorder periodic initial-value problems. In comparison with some...In this paper, two families of high accuracy explicit two-step methods with minimal phase-lag are developed for the numerical integration of special secondorder periodic initial-value problems. In comparison with some methods in [1, 4,6], the advantage of these methods has a higher accuracy and minimal phaselag. The methods proposed in this paper can be considered as a generalization of some methods in [1,3,4]. Numerical examples indicate that these new methods are generally more accurate than the methods used in [3,6].展开更多
文摘目的探讨纤维细胞生长因子2(FGF-2)、微小RNA-206(miR-206)预测闭合性胫骨干骨折术后延迟愈合的价值。方法回顾性分析陆军第八十集团军医院2018年5月至2021年5月行闭合性胫骨干骨折手术的患者136例的临床资料,将术后延迟愈合的患者86例作为观察组,术后正常愈合患者50例为对照组。采用酶联免疫吸附法检测患者血清FGF-2水平,采用实时荧光聚合酶链式反应法检测血清miR-206水平,分析FGF-2、miR-206水平与闭合性胫骨干骨折术后延迟愈合的关系。结果观察组术后1 d、术后1周、术后4周血清FGF-2水平均显著低于对照组[(14.24±2.15)ng/L比(20.36±3.42)ng/L,(21.38±3.27)ng/L比(30.45±4.29)ng/L,(23.59±4.36)ng/L比(36.67±4.51)ng/L](t=7.42、8.42、16.66,均P<0.001),且其水平随着时间推移而逐渐升高;观察组术后1 d miR-206表达量低于对照组(t=7.50,P<0.001),而术后4周miR-206表达量高于对照组(t=17.24,P<0.001),术后1周两组miR-206表达量差异无统计学意义(P>0.05)。单因素分析结果显示,术后感染、FGF-2、miR-206与闭合性胫骨干骨折术后延迟愈合密切相关(均P<0.05)。多因素logistic回归分析结果显示,术后感染(OR=1.93,95%CI:1.20~3.07)、FGF-2(OR=2.10,95%CI:1.31~3.36)、miR-206(OR=2.30,95%CI:1.35~3.89)是影响闭合性胫骨干骨折术后延迟愈合的独立危险因素(均P<0.05)。根据骨折术后延迟愈合患者血清FGF-2、miR-206水平绘制受试者工作特征(ROC)曲线,结果显示,术后4周时FGF-2以29.83 ng/L为最佳截断值时,预测闭合性胫骨干骨折术后延迟愈合的曲线下面积为0.76(95%CI:1.23~3.25),灵敏度、特异度分别为79.34%、68.82%;术后4周时miR-206以0.63为最佳截断值时,预测闭合性胫骨干骨折术后延迟愈合的曲线下面积为0.72(95%CI:1.10~2.45),灵敏度、特异度分别为75.33%、67.25%;两者联合检测预测闭合性胫骨干骨折术后延迟愈合的曲线下面积为0.81(95%CI:1.35~3.26),灵敏度、特异度分别为
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)National Natural Science Foundations of China(Nos.52075244,52002181)。
文摘The simplification of fatigue load spectrum,which can effectively reduce experimental cost,is of great importance for structural fatigue tests.By introducing random variables,the probabilistic tolerance method of removing small amplitude cycles proposed in this paper takes into account the randomness of both load and fatigue limit.The probability of the damage occurrence caused by the removed small loads is calculated to ensure that it cannot exceed the given probabilistic tolerance.Accordingly,the omission level is obtained and the truncated spectrum is formed.The unnotched aluminum sheet specimens are used to perform the fatigue test on the original fatigue spectrum and truncated fatigue spectrum of a transporter.The test results show that there is no statistical difference between the test life of the truncated spectrum and that of the original spectrum,which demonstrates the validity of the small-load-omitting method that considers randomness.
文摘为提高哈希算法的感知性与鲁棒性,提出一种基于块截断编码与邻域空间LBP算子的鲁棒图像哈希算法。将预处理图像分割为非重叠子块,结合奇异值分解SVD(singular value decomposition),获取二次图像,引入块截断编码机制,输出其高、低电平矩和二进制位图;基于LBP(local binary pattern)算子,设计邻域空间LBP模式,获取位图的特征矩阵;构造量化函数,得到高、低电平矩阵对应的紧凑二值序列,利用主成分分析处理特征矩阵,输出二值序列,组合这些二值序列,获取图像哈希。根据Hamming距离,对图像真伪进行认证。实验数据表明,与当前哈希算法相比,所提哈希算法具有更好的抗碰撞性能与感知鲁棒。
文摘为快速进行模型的降阶,结合平衡截断(Balanced Truncation,BT)方法和特征正交分解(Proper Orthogonal Decomposition,POD)方法提出一种模型降阶方法.该方法采用频域POD快照矩阵低阶逼近系统的可控、可观Gram矩阵;通过奇异值分解(Singular Value Decomposition,SVD)提取BT+POD模态,对低能量模态截断形成降阶子空间,并将其映射到全阶系统,从而形成基于状态空间的降阶模型(Reduced Order Model,ROM);该模型就成为全阶模型(Full Order Model,FOM)的ROM.通过对阶数n=406的LTI SISO系统和阶数n=9的2区间电力系统进行的验证表明,在保留BT方法输入输出平衡特性的基础上,该方法效率高于BT方法.
基金State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation (PLN0115).
文摘A family of symmetric (hybrid) two step sixth P-stable methods for the accurate numerical integration of second order periodic initial value problems have been considered in this paper. These methods, which require only three (new) function evaluation per iteration and per step integration. These methods have minimal local truncation error (LTE) and smaller phase-lag of sixth order than some sixth orders P-stable methods in [1-3,10-11]. The theoretical and numerical results show that these methods in this paper are more accurate and efficient than some methods proposed in [1-3,10].
文摘In this paper, two families of high accuracy explicit two-step methods with minimal phase-lag are developed for the numerical integration of special secondorder periodic initial-value problems. In comparison with some methods in [1, 4,6], the advantage of these methods has a higher accuracy and minimal phaselag. The methods proposed in this paper can be considered as a generalization of some methods in [1,3,4]. Numerical examples indicate that these new methods are generally more accurate than the methods used in [3,6].
