高压直流(high voltage direct current,HVDC)输电线路对故障暂态电压信号大多数频段都具有衰减作用,而HVDC的物理边界对高频分量会产生较强的衰减作用,对低频分量会产生一定的放大作用。根据上述特征,提出了一种基于变分模态分解(varia...高压直流(high voltage direct current,HVDC)输电线路对故障暂态电压信号大多数频段都具有衰减作用,而HVDC的物理边界对高频分量会产生较强的衰减作用,对低频分量会产生一定的放大作用。根据上述特征,提出了一种基于变分模态分解(variational mode decomposition,VMD)-麻雀搜索算法(sparrow search algorithm,SSA)和多频段希尔伯特(Hilbert)能量幅值的高压直流输电线路单端量保护方法。利用SSA对VMD参数进行优化后,对故障暂态电压信号进行分解,然后对分解后的各个内涵模态分量(intrinsic mode functions,IMF)进行Hilbert变换求取其200~1200 Hz低频段和8~12 kHz高频段的Hilbert能量,利用低频段和高频段Hilbert能量之比构造故障区段识别保护判据,通过正极和负极其高低频段Hilbert能量和之比来判断故障极。仿真实验证明,所提出的方法能够有效避免利用经验模态分解(empirical mode decomposition,EMD)故障信号时会出现模态混叠这一现象,能准确地辨识出故障区域和故障极,具有较好的耐过渡电阻性,并能有效地保护线路全长。展开更多
目的:探讨两种不同表面粗化处理(砂纸打磨及喷砂)及Ivoclean对唾液浸泡后氧化锆粘接性能的影响。方法:将52个氧化锆瓷块随机分为两组,分别选用不同方法对瓷块表面进行粗化处理:120#水砂纸打磨粗化及喷砂粗化处理。处理后,扫描电镜观察...目的:探讨两种不同表面粗化处理(砂纸打磨及喷砂)及Ivoclean对唾液浸泡后氧化锆粘接性能的影响。方法:将52个氧化锆瓷块随机分为两组,分别选用不同方法对瓷块表面进行粗化处理:120#水砂纸打磨粗化及喷砂粗化处理。处理后,扫描电镜观察其表面形态,X射线荧光光谱仪对陶瓷表面成分进行定性定量分析。将每组试样浸泡于人工唾液后,75%乙醇消毒清洁表面,根据是否配合Ivoclean分为两个亚组;将每组试样与自粘接树脂水门汀Rely X U200树脂水门汀粘接后,万能试验机测试剪切粘接强度,对界面破坏模式进行观察,并对结果进行2×2析因方差统计学分析。结果:四组的剪切粘接强度分别为:19.75±2.05 MPa(砂纸打磨+无Ivoclean)、27.46±2.02MPa(砂纸打磨+Ivoclean)、23.62±2.80MPa(喷砂+无Ivoclean)和29.81±2.61MPa(喷砂+Ivoclean)。析因方差分析结果显示:喷砂处理配合使用Ivoclean,所获得的剪切粘接强度明显高于其它各组(P<0.05)。相同消毒处理条件下,喷砂粗化组的效果均优于砂纸打磨粗化组(F=11.906,P<0.05);相同粗化条件下,乙醇消毒表面后配合Ivoclean使用可明显提升氧化锆的剪切粘接强度(F=84.191,P<0.05);表面粗化处理及清洁方式间无交互效应(F=1.005,P<0.05)。结论:表面粗化处理方式及表面清洁方式均是提高唾液浸泡后氧化锆与树脂水门汀间剪切粘接强度的相关影响因素,两者间无交互效应,喷砂处理配合使用Ivoclean可显著提升唾液浸泡后氧化锆的粘接性能。展开更多
Objective:To explore whether Panax notoginseng saponins(PNS)exhibits heart protective effect in myocardial infarction(MI)rats and to identify the potential signaling pathways involved.Methods:MI rats induced by ligati...Objective:To explore whether Panax notoginseng saponins(PNS)exhibits heart protective effect in myocardial infarction(MI)rats and to identify the potential signaling pathways involved.Methods:MI rats induced by ligating the left anterior descending(LAD)coronary artery were assigned to sham coronary artery ligation or coronary artery ligation.Totally 36 Sprague-Dawley rats were randomly divided into sham group(distilled water,n=9),MI group(distilled water,n=9),PNS group(PNS,40 mg/kg daily,n=9)and fosinopril group(FIP,1.2 mg/kg daily,n=9)according to a random number table.The left ventricular morphology and function were conducted by echocardiography.Histological alterations were evaluated by the stainings of HE and Masson.The serum levels of C reactive protein(CRP),tumor necrosis factorα(TNF-α),growth differentiation factor-15(GDF-15)and the ratio of metalloproteinase-9(MMP-9)and tissue inhibitor of MMP-9(TIMP-1)were determined by ELISA.The levels of activating transcription factor 3(ATF3),mitogen-activated protein kinase kinase 3(MAP2 K3),p38 mitogen-activated protein kinase(p38 MAPK),phosphorylation of p38 MAPK(p-p38 MAPK),transforming growth factor-β(TGF-β1),collagenⅠ,nuclear factor kappa B p65(NFκB p65),phosphorylation of NFκB p65(p-NFκB p65),and phosphorylation of inhibitory kappa Bα(p-IκBα)in hearts were measured by Western blot and immunohistochemical staining,respectively.Results:PNS improved cardiac function and fibrosis in MI rats(P<0.05).The serum levels of CRP,TNF-α,GDF-15 and the ratio of MMP9/TIMP1 were reversed by PNS in MI rats.The expressions of TGF-β1,collagenⅠ,MAP2 K3,p38 MAPK,p-p38 MAPK,NFκB p65,p-NFκB p65,and p-IκBαwere down-regulated,while ATF3 increased with the treatment of PNS(P<0.05).Conclusions:PNS may improve cardiac function and fibrosis in MI rats via regulating ATF3/MAP2 K3/p38 MAPK and NFκB signaling pathways.These results suggest the potential of PNS in preventing the development of ventricular remodeling in MI rats.展开更多
文摘目的:探讨两种不同表面粗化处理(砂纸打磨及喷砂)及Ivoclean对唾液浸泡后氧化锆粘接性能的影响。方法:将52个氧化锆瓷块随机分为两组,分别选用不同方法对瓷块表面进行粗化处理:120#水砂纸打磨粗化及喷砂粗化处理。处理后,扫描电镜观察其表面形态,X射线荧光光谱仪对陶瓷表面成分进行定性定量分析。将每组试样浸泡于人工唾液后,75%乙醇消毒清洁表面,根据是否配合Ivoclean分为两个亚组;将每组试样与自粘接树脂水门汀Rely X U200树脂水门汀粘接后,万能试验机测试剪切粘接强度,对界面破坏模式进行观察,并对结果进行2×2析因方差统计学分析。结果:四组的剪切粘接强度分别为:19.75±2.05 MPa(砂纸打磨+无Ivoclean)、27.46±2.02MPa(砂纸打磨+Ivoclean)、23.62±2.80MPa(喷砂+无Ivoclean)和29.81±2.61MPa(喷砂+Ivoclean)。析因方差分析结果显示:喷砂处理配合使用Ivoclean,所获得的剪切粘接强度明显高于其它各组(P<0.05)。相同消毒处理条件下,喷砂粗化组的效果均优于砂纸打磨粗化组(F=11.906,P<0.05);相同粗化条件下,乙醇消毒表面后配合Ivoclean使用可明显提升氧化锆的剪切粘接强度(F=84.191,P<0.05);表面粗化处理及清洁方式间无交互效应(F=1.005,P<0.05)。结论:表面粗化处理方式及表面清洁方式均是提高唾液浸泡后氧化锆与树脂水门汀间剪切粘接强度的相关影响因素,两者间无交互效应,喷砂处理配合使用Ivoclean可显著提升唾液浸泡后氧化锆的粘接性能。
文摘目的运用系统评价黄连温胆汤及其加减方治疗冠心病稳定型心绞痛的有效性及安全性。方法计算机检索中国知网(CNKI)、中国生物医学文献服务系统(Sino Med)、维普中文期刊服务平台(VIP)、万方数据知识服务平台(Wanfang Data)、Pubmed、Embase、Cochrance数据库文献,检索范围均为建库以来至2019年5月公开发表的与黄连温胆汤治疗冠心病稳定型心绞痛相关的临床试验。由2位研究员独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用Rev Man 5.3软件进行Meta分析。结果共纳入16篇文献,包括1267例研究对象。与常规西药治疗相比,黄连温胆汤及其加减方在稳定型心绞痛的治疗中,可减少心绞痛发作次数,缩短心绞痛发作时间,调节异常血脂指标,改善临床疗效、中医证候积分疗效及心电图疗效,差异有统计学意义(P<0.05)。结论与常规西医治疗相比,黄连温胆汤加减治疗冠心病稳定型心绞痛疗效较好,可减少发作频率,调节血脂情况,改善患者症状,值得临床推荐。
基金Supported by the National Significant New Drugs Development(No.2013ZX09301307)National Natural Science Foundation of China(No.81774168)。
文摘Objective:To explore whether Panax notoginseng saponins(PNS)exhibits heart protective effect in myocardial infarction(MI)rats and to identify the potential signaling pathways involved.Methods:MI rats induced by ligating the left anterior descending(LAD)coronary artery were assigned to sham coronary artery ligation or coronary artery ligation.Totally 36 Sprague-Dawley rats were randomly divided into sham group(distilled water,n=9),MI group(distilled water,n=9),PNS group(PNS,40 mg/kg daily,n=9)and fosinopril group(FIP,1.2 mg/kg daily,n=9)according to a random number table.The left ventricular morphology and function were conducted by echocardiography.Histological alterations were evaluated by the stainings of HE and Masson.The serum levels of C reactive protein(CRP),tumor necrosis factorα(TNF-α),growth differentiation factor-15(GDF-15)and the ratio of metalloproteinase-9(MMP-9)and tissue inhibitor of MMP-9(TIMP-1)were determined by ELISA.The levels of activating transcription factor 3(ATF3),mitogen-activated protein kinase kinase 3(MAP2 K3),p38 mitogen-activated protein kinase(p38 MAPK),phosphorylation of p38 MAPK(p-p38 MAPK),transforming growth factor-β(TGF-β1),collagenⅠ,nuclear factor kappa B p65(NFκB p65),phosphorylation of NFκB p65(p-NFκB p65),and phosphorylation of inhibitory kappa Bα(p-IκBα)in hearts were measured by Western blot and immunohistochemical staining,respectively.Results:PNS improved cardiac function and fibrosis in MI rats(P<0.05).The serum levels of CRP,TNF-α,GDF-15 and the ratio of MMP9/TIMP1 were reversed by PNS in MI rats.The expressions of TGF-β1,collagenⅠ,MAP2 K3,p38 MAPK,p-p38 MAPK,NFκB p65,p-NFκB p65,and p-IκBαwere down-regulated,while ATF3 increased with the treatment of PNS(P<0.05).Conclusions:PNS may improve cardiac function and fibrosis in MI rats via regulating ATF3/MAP2 K3/p38 MAPK and NFκB signaling pathways.These results suggest the potential of PNS in preventing the development of ventricular remodeling in MI rats.
