40 research outputs found

    非编码sRNA在细菌耐药机制方面的研究进展

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    近年来的研究发现,细菌应答抗生素压力时会产生特异的非编码小RNA(small RNA,sRNA)谱,进而可能调控下游基因的表达,帮助细菌克服抗生素压力。sRNA以各种方式调控细菌耐药相关基因(如抗生素转运蛋白、药物外排泵、细胞被膜的合成与修饰),参与细菌耐药网络。因此,sRNA及其相关因子(如Hfq)可能被用作抗菌治疗的靶标。本文将从sRNA应答抗生素压力并产生抗生素耐药及其作为药物靶点的前景等方面,综述sRNA在细菌耐药调控方面的研究进展。国家自然科学基金(No.31370166、No.81473251和No.81301474);;福建省自然科学基金(No.2015J01345和No.2014J01139);;厦门大学校长基金(No.20720160060

    Benchmark-problem investigation for seismic response of a large-span cable-stayed bridge based on nonlinear stochastic optimal control

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    大跨度斜拉桥Benchmark问题的振动控制研究是当前国际结构控制研讨会的重要议题之一。以美国Bill Emerson Memorial斜拉桥第二阶段Benchmark模型为研究对象,在非线性随机动力学与控制的拟哈密顿理论体系框架下,运用基于随机平均法和随机动态规划原理的非线性随机最优(NSO)控制策略,对地震作用下的Benchmark模型进行MATLAB仿真分析。将最优控制力和性能评价指标与线性二次型Gauss(LQG)控制的计算结果进行对比,得出非线性随机最优控制策略能够更加有效地抑制斜拉桥的地震响应,提高结构的动力稳定性和抗震能力,具有更好的控制效果,对实际桥梁工程的振动控制具有较强的指导意义和适用价值。Investigation of vibration control for benchmark problems on large-span,cable-stayed bridge is one of the most important research topics in the current International Symposium on Structural Control. This paper studied secondstage benchmark problems on the Bill Emerson Memorial cable-stayed bridge. In terms of Hamiltonian theory for nonlinear stochastic dynamics and control, the benchmark model under seismic excitations was investigated using MATLAB simulation analysis,based on the stochastic averaging method and stochastic dynamic-programming principle. Comparison of analysis results for optimal forces and performance-evaluation indices between the nonlinear stochastic optimal( NSO)control strategy and the linear quadratic Gaussian( LQG) control strategy revealed that the former control strategy mitigates the seismic response of the cable-stayed bridge more effectively than the latter,thereby enhancing structural dynamic stability and earthquake resistance. In conclusion,the NSO control strategy demonstrates better control effect and presents instructive references and practical significance for vibration control of bridge-engineering applications.福建省青年人才项目(2008F3100

    两种戊型肝炎IgG抗体检测试剂的比较

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    目的比较2种国产戊型肝炎IgG抗体诊断试剂(E2-IgG和X-IgG)的特异性与敏感度。方法利用2种试剂对2006年江苏省某市普通人群的流行病调查血清标本460份和经过巢式逆转录聚合酶链式反应(nest-RT-PCR)鉴定为HEV核酸阳性的临床戊型肝炎患者血清标本72份进行平行检测,并以免疫印迹实验(Westernblot,WB)和中和单抗阻断试验进行验证。结果1.460份流行病调查血清标本中WB阳性188份。2.188份WB阳性标本中E2-IgG的检测敏感度为99.5,特异度为99.6,阳性预测值99.5,阴性预测值99.6,准确性99.6;X-IgG的检测敏感度为21.3,特异度为97.4,阳性预测值85.1,阴性预测值64.1,准确性66.3。3.E2-IgG阴、阳性A450/A620值的分布在临界值附近分界明显,小于临界值的A450/A620值取对数后呈正态分布,而阳性血清A450/A620值的高低与其WB的反应强度正相关。4.E2-IgG阳性、X-IgG阴性的血清共148份,中和单抗阻断阳性率为98,WB阳性率99.3。5.经PCR鉴定为HEV核酸阳性的急性戊型肝炎患者血清中E2-IgG敏感度98.6,X-IgG敏感度80.6(χ2=10.7,P<0.01)。结论E2-IgG在不同人群中均能较好的反映体内戊型肝炎抗体存在的真实情况

    Analysis on the epidemiological characteristics of the sporadic cases with hepatitis E infection in the rural area in Jiangsu province

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    目的了解江苏省农村散发性戊型肝炎的流行病学特征。方法通过建立覆盖市、镇、村三级医疗卫生服务机构的疑似肝炎主动监测网络,系统全面地监测戊型肝炎病例的发病情况。结果主动监测网络的敏感性明显高于网络报告系统,能更加准确、全面地掌握戊肝的发病规律。结果显示戊型肝炎病例占疑似急性肝炎病例的26.7%,男性戊肝发病率高于女性(P<0.01);发病随着年龄增长而上升,多见35岁以上人群;全年均有发病,冬春季节较高;戊型肝炎病毒株HEV1、4型并存,但以HEV4型为主(92.5%)。结论疑似肝炎主动监测系统数据显示目前戊肝发病率有被低估的风险。To understand the epidemiological characteristics of the sporadic cases with hepatitis E infection in the rural area of Jiangsu province,the prevalence of hepatitis E infection was surveyed systemically and completely through the initiatively monitoring system for the suspected cases of hepatitis E covering the city,town and village levels of medical and health service organizations.It was found that the initiatively monitoring system for suspected hepatitis E cases reflected the incidence of hepatitis E more accurately and comprehensively and was proved to be more sensitive than the network reporting system.The cases with hepatitis E accounted to 26.7% of the suspected cases with acute hepatitis and they were more frequent in male than in female.The incidence of hepatitis E increased with advance of age and most of cases occurred with age over 35.Estimated incidence was stable on the whole year,but rose up in winter and spring.The HEV type 1 and type 4 co-existed,but the HEV type 4 was proved to be the main type(92.5%).From the above observations,it seems that the initiatively monitoring system for the suspected cases of hepatitis E may be under-estimated for the risk of the hepatitis E infection in rural area of Jiangsu province.国家高技术研究发展计划(863计划)(2006AA02A209)资

    基于最小聚类求解k-means问题算法

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    仿生模式识别在单镜头人脸识别中的应用

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    提出了一种基于仿生模式识别(Biomimatic Pattern Recognition)和多权值神经元网络(Multi-Weights.Neu-ral Network)的人脸识别新方法.对仿生模式识别理论在人脸识别中的应用模型作了讨论,并且介绍了一种新的人脸特征提取方法.本文通过实验对本文提出的基于仿生模式识别的方法和基于K近邻的方法做了对比,实验结果表明本文的方法克服了对未训练类型的人脸误识问题,提高了人脸识别系统的训练速度和正确识别率

    孤啡肽及其片段的合成和构效关系

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    孤啡肽及其片段的合成和构效关系

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    痛稳素的合成及其对血管活性的影响

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