检索结果-南通市图书馆

Cryoballoon ablation of persistent atrial fibrillation for de novo pulmonary vein isolation:a single-center follow-up study

引用

Journal of Geriatric Cardiology 2022年第10期19卷 725-733页

作者： Zhong-Jing CAO Xiao-Gang GUO Qi SUN Yan-Qiao CHEN Hai-yang XIE jian-du yang Hui-Qiang WEI Jia-Hui LI jian MA Department of Cardiology Sichuan Academy of Medical Sciences&Sichuan Provincial People’s HospitalSchool of Medicine UESTCChengduChina State Key Laboratory of Cardiovascular Disease Arrhythmia CenterFuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Department of Cardiology Guangdong Cardiovascular InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical ScienceGuangzhouChina

BACKGROUND Pulmonary vein isolation(PVI)alone for persistent atrial fibrillation(PersAF)remains controversial.The characteristics of cryoballoon ablation(CBA)to treat PersAF and the blanking period recurrence are underreported.METHODS This study retrospectively analyzed patients with PersAF undergoing second-generation CBA for de novo PVI.The post-procedural efficacy and survival analysis were compared between patients with different PersAF durations.The multivariate Cox regression analysis was used to detect the risk factors for recurrence.Early and long-term recurrence were analyzed relative to each other.RESULTS A total of 329 patients were enrolled,with a median PersAF duration of 4.0 months(interquartile range:2.0–12.0 months);257 patients(78.1%)were male.Kaplan-Meier analysis of freedom from atrial fibrillation recurrence at 12,24,and 30 months showed 71.0%,58.5%,and 54.9%,respectively.Early PersAF had a relatively favorable survival rate and a narrow P-wave duration of restoring sinus rhythm compared with that of PersAF lasting more than three months(Pduration and left atrial anteroposterior diameter≥42 mm were the risk factors for atrial fibrillation recurrence after CBA[hazard ratio(HR)=1.89,95%CI:1.01–1.4,P=0.042;HR=3.6,95%CI:2.4–5.4,Pduration and left atrial size were risk factors for atrial fibrillation recurrence after CBA.Blanking period recurrence was associated with long-term recurrence.

关键词： balloon fibrillation atrial

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pulmonary vein isolation implemented by second-generation cryoballoon for treating hypertrophic cardiomyopathy patients with symptomatic atrial fibrillation:a case-control study

引用

Journal of Geriatric Cardiology 2020年第8期17卷 476-485页

作者： Zhong-Jing CAO Xiao-Gang GUO Qi SUN jian-du yang Hui-Qiang WEI Shu ZHANG jian MA Arrhythmia Center State Key Laboratory of Cardiovascular DiseaseFuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Department of Cardiology Guangdong Cardiovascular InstituteGuangdong Provincial People's HospitalGuangdong Academy of Medical ScienceGuangzhouChina

Background Atrial fibrillation(AF)is a generally acknowledged turning-point of the natural history of hypertrophic cardiomyopathy(HCM);however,data from the cryoballoon ablation(CBA)for AF in HCM patients are relatively scarce.The study aimed to evaluate the efficacy and safety of CBA in HCM patients with AF.Methods We retrospectively analyzed HCM patients among 1253 patients with symptomatic AF who underwent CBA for pulmonary vein isolation in a single center.The study analyzed the AF recurrence and assessed the CBA indexes,including nadir temperature,time-to-isolation,CBA failure,pulmonary vein potentials(PVPs),and redo procedure.Results A total of 108 patients were included(mean age:59.0±6.9 years),27 patients(25%)had HCM,with the median follow-up duration of 25.5 months.The one-year AF-free rates were 79.0%vs.63.0%(non-HCM vs.HCM),while the two-year AF-free rates were 77.8%vs.55.1%[hazard ratio(HR)=2.758,log-rank P=0.024].Patients with persistent AF had poor AF-free rates compared to those with paroxysmal AF(P<0.001).The CBA failure was the most common in the right inferior pulmonary veins,which had the lowest PVPs.Multivariate Cox regression analysis indicated that HCM and persistent AF were risk factors for AF recurrence(HR=2.74,95%CI:1.29–5.79,P=0.008;and HR=3.97,95%CI:1.85–8.54,P<0.001,respectively).Conclusions The CBA can be effectively and safely used to treat HCM patients with symptomatic AF.The freedom from AF for HCM patients after CBA is relatively low compared to that for non-HCM patients.

关键词： Atrial fibrillation Cryoballoon ablation Hypertrophic cardiomyopathy Pulmonary vein isolation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Vagus nerve stimulation in cerebral stroke:biological mechanisms,therapeutic modalities,clinical applications,and future directions

引用

Neural Regeneration Research 2024年第8期19卷 1707-1717页

作者： Li du Xuan He Xiaoxing Xiong Xu Zhang Zhihong jian Zhenxing yang Department of Anesthesiology Renmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina Department of Neurosurgery Renmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina

Stroke is a major disorder of the central nervous system that poses a serious threat to human life and quality of life.Many stro ke victims are left with long-term neurological dysfunction,which adversely affects the well-being of the individual and the broader socioeconomic impact.Currently,poststroke brain dysfunction is a major and difficult area of treatment.Vagus nerve stimulation is a Food and Drug Administration-approved exploratory treatment option for autis m,refractory depression,epilepsy,and Alzheimer’s disease.It is expected to be a novel therapeutic technique for the treatment of stroke owing to its association with multiple mechanisms such as alte ring neurotransmitters and the plasticity of central neuro ns.In animal models of acute ischemic stroke,vagus nerve stimulation has been shown to reduce infarct size,reduce post-stroke neurological damage,and improve learning and memory capacity in rats with stroke by reducing the inflammatory response,regulating bloodbrain barrier permeability,and promoting angiogenesis and neurogenesis.At present,vagus nerve stimulation includes both invasive and non-invasive vagus nerve stimulation.Clinical studies have found that invasive vagus nerve stimulation combined with rehabilitation therapy is effective in im proving upper limb motor and cognitive abilities in stroke patients.Further clinical studies have shown that non-invasive vagus nerve stimulation,including ear/ce rvical vagus nerve stimulation,can stimulate vagal projections to the central nervous system similarly to invasive vagus nerve stimulation and can have the same effect.In this paper,we first describe the multiple effects of vagus nerve stimulation in stroke,and then discuss in depth its neuroprotective mechanisms in ischemic stroke.We go on to outline the res ults of the current major clinical applications of invasive and non-invasive vagus nerve stimulation.Finally,we provide a more comprehensive evaluation of the advantages and disadvantages of different types of vagus nerve stimulation in the

关键词： cerebral stroke neuroplasticity non-invasive vagus nerve stimulation rehabilitation vagus nerve stimulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Distributed Cooperative Secondary Voltage Control in an Unbalanced Microgrid

引用

CSEE Journal of Power and Energy Systems 2024年第1期10卷 222-234页

作者： Xiangzhen yang Haixi Zhao Mengke duan Yan du Haining Wang jian Zhang School of Electrical Engineering and Automation Hefei University of TechnologyHefei 23009China

The negative-sequence reactive power-conductance(Q^(−)-G) droop control strategy is a conventional method to compensate for the output unbalanced voltages in an islanded MG.Nevertheless, the conflict between unbalanced voltage compensation and negative-sequence reactive power sharing, caused bythe impedance mismatching of distribution lines and distributedgenerators, has not been solved only by Q^(−)-G droop control.In this paper, a distributed cooperative secondary unbalancedvoltage control strategy is proposed to decrease the outputvoltage unbalance factor (VUF) of each droop-controlled DG,as well as to further enhance the negative-sequence reactivepower sharing effectiveness among DGs by properly shiftingup and down the Q^(−)-G droop characteristics of each DG.An algorithm for adaptive VUF weight coefficient is proposedto better suppress VUF under severe imbalance conditions.Furthermore, a negative-sequence small-signal model of an MGunder an unbalanced condition, considering the communicationdelay time of the proposed SUVC, is established to analyze thesystem’s stability and transient performance under the influenceof some critical parameters. Finally, the effectiveness of theproposed strategy is validated by the simulation results froma real-time emulator of StarSim HIL.

关键词： Distributed cooperative control MG negativesequence reactive power starsim real-time platform time delay voltage unbalance compensation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The influence of the leading-edge angle of subgrade on the aerodynamic loads of a high-speed train in a wind tunnel

引用

Transportation Safety and Environment 2024年第2期6卷 45-54页

作者： Zeyun yang Gang Xu Fan Wu Lei Zhang jian du Dmitri Vainchtein Key Labor atory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075HunanChina CRRC Academy(Qingdao)Co. Ltd.Qingdao 266111ShandongChina CRRC Qingdao Sifang Co. Ltd.Qingdao 266111ShandongChina Nyheim Plasma Institute Drexel UniversityCamden 08103USA

The purpose of this study is to establish the correlation between the boundary layer over the subgrade and the aerodynamic loads act-ing on the train model in conventional wind tunnel tests.Firstly,flow characteristics around the subgrade with different leading-edge angles(15°,30°and 45°)are investigated through the particle image velocimetry(PIV)experimental test method.Then,wind tunnel tests of the aerodynamic performance of a high-speed train are carried out.The results are compared with previous experimental data obtained by moving model tests.Results show that,due to the presence of a boundary layer,the pressure acting on the lower part of the train head decreases,while other locations are not significantly affected.This is the reason for the reduction of the aerodynamic drag and lift on the train.In addition,the reduction effects become more obvious when the thickness of the boundary layer increases.The experimental results obtained could serve as a calibration of aerodynamic forces for wind tunnel tests on high-speed trains.

关键词： high-speed train ground effect aerodynamic performance wind tunnel test PIV experiment

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Development in oxide metallurgy for improving the weldability of high -strength low-alloy steel-Combined deoxidizers and microalloying elements

引用

International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1263-1284页

作者： Tingting Li jian yang State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

The mechanisms of oxide metallurgy include inducing the formation of intragranular acicular ferrite(IAF)using micron-sized inclusions and restricting the growth of prior austenite grains(PAGs)by nanosized particles during welding.The chaotically oriented IAF and refined PAGs inhibit crack initiation and propagation in the steel,resulting in high impact toughness.This work summarizes the com-bined effect of deoxidizers and alloying elements,with the aim to provide a new perspective for the research and practice related to im-proving the impact toughness of the heat affected zone(HAZ)during the high heat input welding.Ti complex deoxidation with other strong deoxidants,such as Mg,Ca,Zr,and rare earth metals(REMs),can improve the toughness of the heat-affected zone(HAZ)by re-fining PAGs or increasing IAF contents.However,it is difficult to identify the specific phase responsible for IAF nucleation because ef-fective inclusions formed by complex deoxidation are usually multiphase.Increasing alloying elements,such as C,Si,Al,Nb,or Cr,con-tents can impair HAZ toughness.A high C content typically increases the number of coarse carbides and decreases the potency of IAF formation.Si,Cr,or Al addition leads to the formation of undesirable microstructures.Nb reduces the high-temperature stability of the precipitates.Mo,V,and B can enhance HAZ toughness.Mo-containing precipitates present good thermal stability.VN or V(C,N)is ef-fective in promoting IAF nucleation due to its good coherent crystallographic relationship with ferrite.The formation of the B-depleted zone around the inclusion promotes IAF formation.The interactions between alloying elements are complex,and the effect of adding dif-ferent alloying elements remains to be evaluated.In the future,the interactions between various alloying elements and their effects on ox-ide metallurgy,as well as the calculation of the nucleation effects of effective inclusions using first principles calculations will become the focus of oxide metallurgy.

关键词： oxide metallurgy technology heat affected zone high-strength low-alloy steel intragranular acicular ferrite microalloying element

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Sparse Modal Decomposition Method Addressing Underdetermined Vortex-Induced Vibration Reconstruction Problem for Marine Risers

引用

China Ocean Engineering 2024年第2期38卷 285-296页

作者： du Zun-feng ZHU Hai-ming YU jian-xing State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation School of Civil EngineeringTianjin UniversityTianjin 300350China

When investigating the vortex-induced vibration(VIV)of marine risers,extrapolating the dynamic response on the entire length based on limited sensor measurements is a crucial step in both laboratory experiments and fatigue monitoring of real risers.The problem is conventionally solved using the modal decomposition method,based on the principle that the response can be approximated by a weighted sum of limited vibration modes.However,the method is not valid when the problem is underdetermined,i.e.,the number of unknown mode weights is more than the number of known measurements.This study proposed a sparse modal decomposition method based on the compressed sensing theory and the Compressive Sampling Matching Pursuit(Co Sa MP)algorithm,exploiting the sparsity of VIV in the modal space.In the validation study based on high-order VIV experiment data,the proposed method successfully reconstructed the response using only seven acceleration measurements when the conventional methods failed.A primary advantage of the proposed method is that it offers a completely data-driven approach for the underdetermined VIV reconstruction problem,which is more favorable than existing model-dependent solutions for many practical applications such as riser structural health monitoring.

关键词： motion reconstruction vortex-induced vibration(VIV) marine riser modal decomposition method compressed sensing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influence of sintering time on microstructure and properties of hot oscillatory pressing sintered W–Cu refractory alloys

引用

Tungsten 2024年第2期6卷 323-332页

作者： Zi-Qian Wu Wei Zhao Ka Gao Shi-Hao du Qing-Quan Kong De-jian Sun yang Gao School of Materials Science and Engineering Zhengzhou University of AeronauticsZhengzhou 450015China School of Mechanical Engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of General Medicine Changhai HospitalShanghai 200000China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and TechnologyWuhan 430081China Sichuan Province Engineering Technology Research Center of Powder Metallurgy Chengdu UniversityChengdu 610106China

W–Cu refractory alloys are widely used in aerospace,aviation,electronics,power,and other fi elds.However,because of its large melting point diff erence between alloy elements,the conventional powder metallurgy method required a long time of high temperature sintering is very likely to cause low density and abnormal grain size growth.Therefore,90W-10Cu refractory alloys were successfully prepared by hot oscillatory pressing(HOP)under diff erent sintering time in this work.Then the infl uence of sintering time on the microstructure,grain size,density,Vickers hardness,room-tensile property,and electrical conductivity of the W–Cu refractory alloy was systematically invested.The results showed that during the short sintering time(30–90 min),the density,Vickers hardness,tensile strength,and electrical conductivity of the W–Cu refractory alloy increased signifi cantly to 98.7%,163.29 HV 30,507.3 MPa,and 14.2%International Annealed Copper Standard with the sintering time increasing,respectively,while its grain size showed no obvious change.When the sintering time further increased to 120 min,the density was basically consistent with the sintering time of 90 min.Nevertheless,the prolonged high temperature sintering resulted in the grain growth of the samples,which caused the deterioration of the Vickers hardness,room-tensile strength,and conductivity properties of the W–Cu refractory alloy.At the same sintering time,the density,Vickers hardness,and electrical conductivity of the HOP sintered W–Cu refractory alloy were signifi cantly higher than those of the HP sintered sample.It was indicated that high density,fi ne-grain,and excellent properties W–Cu refractory alloys could be prepared by hot oscillatory pressing under appropriate sintering time.

关键词： W–Cu refractory alloy Hot oscillatory pressing Sintering time Microstructure Property

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Unveiling the adaptation strategies of woody plants in remnant forest patches to spatiotemporal urban expansion through leaf trait networks

引用

Forest Ecosystems 2024年第2期11卷 247-254页

作者： Mengping jian Jingyi yang College of Forestry Guizhou UniversityGuiyang550025China

Background:With the expansion of urban areas,the remnants of forested areas play a crucial role in preserving biodiversity in urban environments.This study aimed to explore the impact of spatiotemporal urban expansion on the networks of leaf traits in woody plants within remnant forest patches,thereby enhancing our understanding of plant adaptive strategies and contributing to the conservation of urban biodiversity.Methods:Our study examined woody plants within 120 sample plots across 15 remnant forest patches in Guiyang,China.We constructed leaf trait networks (LTNs) based on 26 anatomical,structural,and compositional leaf traits and assessed the effects of the spatiotemporal dynamics of urban expansion on these LTNs.Results and conclusions:Our results indicate that shrubs within these patches have greater average path lengths and diameters than trees.With increasing urban expansion intensity,we observed a rise in the edge density of the LTN-shrubs.Additionally,modularity within the networks of shrubs decreased as road density and urban expansion intensity increased,and increases in the average path length and average clustering coefficient for shrubs were observed with a rise in the composite terrain complexity index.Notably,patches subjected to‘leapfrog’expansion exhibited greater average patch length and diameter than those experiencing edge growth.Stomatal traits were found to have high degree centrality within these networks,signifying their substantial contribution to multiple functions.In urban remnant forests,shrubs bolster their resilience to variable environmental pressures by augmenting the complexity of their leaf trait networks.

关键词： Urban remnant forest patch Woody plant Leaf trait network Plant adaptation strategy Spatiotemporal urban expansion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Assessment of the right and left ventricular function in patients with cor pulmonale using high-definition CT

引用

Chinese Medical Journal 2013年第19期126卷 3639-3644页

作者： GAO Yan QIN jian du Xiang-ying yang Jing LI Kun-cheng Department of Radiology Xuanwu Hospital of Capital MedicalUniversity Beijing 100053 China

Background Cor pulmonale is often associated with changes of structure and function of the right ventricle （RV） and thus further affects functional changes of the left heart.Our study aimed to assess the left ventricular （LV） and RV function in patients with cor pulmonale using high-definition CT （HDCT）.Methods We prospectively studied 18 cor pulmonale patients determined by the pulmonary function test,clinical examination,chest radiograph,electrocardiogram,and echocardiogram.The subject group was compared to a control group consisting of 18 subjects.The RV and LV functions and RV myocardial mass （MM） were obtained by HDCT in the two groups.The results were compared between the two groups using the independent sample t test.Echocardiographic examination for cardiac function analysis was performed on the same day.Results The RV end-diastolic volume （EDV）,RV end-systolic volume （ESV） and RV myocardial mass were significantly larger in the 18 cor pulmonale patients than in the control group （P〈0.05）.The right ventricular ejection fraction （RVEF） was significantly lower in the 18 cor pulmonale patients than in controls （P〈0.01）.The left ventricular EDV （LVEDV） and LVEF were significantly lower in cor pulmonale patients than in controls （P〈0.01）.There were strong correlations between MDCT and echocardiography,rRVEF=0.839 and rLVEF=0.916,respectively.Conclusions HDCT can accurately quantify RV and LV function.The right ventricular function is impaired in patients with cor pulmonale,while at the same time the left ventricular function is also impaired.

关键词： cor pulmonale ventricular function high-definition CT myocardial mass

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：