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Transcatheter Aortic Valve Replacement in Patients ≥80 and <80 Years of Age with Aortic Valve Stenosis at Moderate Surgical Risk: Findings from an Observational Study in the Vietnamese Population
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作者 Khoa Quoc Nguyen Duong Van Nguyen +6 位作者 Thuy Thi La Tan Van Nguyen The Ngoc Ha Than Thach NNguyen Hoang VK Dinh Cong Duc Nguyen Nhan Vo Thanh 《Cardiovascular Innovations and Applications》 2024年第1期255-265,共11页
Objectives:The increasing number of elderly patients with severe aortic valve stenosis undergoing transcatheter aortic valve replacement(TAVR)has prompted concerns regarding their clinical outcomes compared with the y... Objectives:The increasing number of elderly patients with severe aortic valve stenosis undergoing transcatheter aortic valve replacement(TAVR)has prompted concerns regarding their clinical outcomes compared with the younger population.This study evaluated the outcomes of TAVR on the basis of age group(<80 or≥80 years)amongVietnamese patients with severe aortic valve stenosis at intermediate surgical risk.Methods:From March 2017 to December 2022,21 patients≥80 years of age and 69 patients<80 years of age under-went TAVI at a single center.Clinical characteristics,procedures,and outcomes at 30 days and 1 year were compared with the Valve Academic Research Consortium(VARC-2)criteria.Results:Patients≥80 years of age had a higher prevalence of comorbidities but no significant differences in other clinical characteristics and procedures.No statistically significant differences were observed in procedural mortality(4.8%vs.0.0%,P=0.233),30-day mortality(5.0%vs.1.5%,P=0.405),and 1-year mortality(11.8%vs.3.7%,P=0.241)between age groups.Major endpoints at specified time points also showed no significant differences.Conclusions:TAVR in patients with aortic stenosis at intermediate surgical risk has similar clinical outcomes at 30 days and 1 year,according to VARC-2 criteria,with no statistically significant age-associated differences(≥80 vs.<80 years).However,further studies with larger patient populations are needed to better understand the effects of age on TAVI outcomes in patients with similar characteristics. 展开更多
关键词 TAVR clinical outcome <80 years old ≥80 years old
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基于可调石墨烯超表面的宽角度动态波束控制 被引量:6
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作者 李小兵 陆卫兵 +1 位作者 刘震国 陈昊 《物理学报》 SCIE EI CAS CSCD 北大核心 2018年第18期91-97,共7页
可调控超表面可用于动态控制空间波束的方向,具有很高的应用价值.石墨烯是一种可调的二维材料,它的电导率可以通过外加电压控制,利用这一特性可设计基于石墨烯的可调控超表面.超表面控制反射波束时的理论依据是广义的斯涅耳反射定律.反... 可调控超表面可用于动态控制空间波束的方向,具有很高的应用价值.石墨烯是一种可调的二维材料,它的电导率可以通过外加电压控制,利用这一特性可设计基于石墨烯的可调控超表面.超表面控制反射波束时的理论依据是广义的斯涅耳反射定律.反射角度可通过沿超表面的相位梯度进行控制.但是这种方法有局限性,当超表面单元固定时,反射角度只能取有限个离散的值.本文设计了基于石墨烯的可调超表面,并采用一种基于卷积运算定理的波束控制方法,实现了反射波角度的大范围动态控制.在1.75 THz垂直入射平面波激励下,反射角度可以从5?变化到70?,间隔小于10?.数值模拟结果与理论计算结果一致. 展开更多
关键词 超表面 石墨烯 波束控制 可调控
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梅州市桉树林油桐尺蠖和桉树落祝蛾的发生及防治 被引量:3
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作者 戴宏芳 刘波 +2 位作者 曹春鹏 李家增 王建国 《桉树科技》 2022年第1期53-55,共3页
结合广东梅州区域最近几年桉树虫害发生情况,总结生产中遇到的2种主要虫害(油桐尺蠖和桉树落祝蛾)的发生及防治经验。油桐尺蠖为一年多代,每年呈现上升趋势,对桉树生长影响非常大。2021年在梅州市发现了桉树落祝蛾危害桉树,其危害性不... 结合广东梅州区域最近几年桉树虫害发生情况,总结生产中遇到的2种主要虫害(油桐尺蠖和桉树落祝蛾)的发生及防治经验。油桐尺蠖为一年多代,每年呈现上升趋势,对桉树生长影响非常大。2021年在梅州市发现了桉树落祝蛾危害桉树,其危害性不亚于油桐尺蠖,由于其属于杂食性害虫,给防治工作带来一定考验。 展开更多
关键词 油桐尺蠖 桉树落祝蛾 发生 防治
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The Future of Gas to Liquids as a Gas Monetisation Option 被引量:8
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作者 Hock Cheng Heng Suhaili Idrus 《Journal of Natural Gas Chemistry》 CAS CSCD 2004年第2期63-70,共8页
The paper introduces gas to liquids (GTL) as a monetising option from a technology, marketing and project perspective. GTL is complementary to LNG and pipelines. At the same time, using natural gas as a source for fue... The paper introduces gas to liquids (GTL) as a monetising option from a technology, marketing and project perspective. GTL is complementary to LNG and pipelines. At the same time, using natural gas as a source for fuels in the form of GTL helps countries around the world to diversify their energy supplies. Furthermore, gas-based products are inherently cleaner than oil products. Shell's proprietary GTL technology or SMDS (Shell Middle Distillates Synthesis), is discussed in some detail. The paper also covers the challenges for successful implementation of GTL projects and why Shell is well positioned to take a lead in the industry on the basis of its long standing and broad experience in GTL research, plant operations, marketing and excellent track record in mega projects in the last thirty years. Shell's commitment to GTL is best demonstrated by the recent signing of a Heads of Agreement with Qatar Petroleum for the construction of the world's largest GTL plant. A key success factor is Shell's experience with marketing quantities of high quality GTL products from its 12,500 barrels per day plant at Bintulu, Malaysia since 1993. Further marketing opportunities will arise when new GTL capacity comes on-stream in the middle east when more quantities will become available to bulk users. Amongst the most interesting market will be automotive transportation, where clean GTL fuels can be positioned as an 'alternative fuel beyond oil' providing energy security to host countries. Shell is actively engaging with a number of regulators, automotive companies and governments worldwide including China, to demonstrate the performance of GTL and its cost effectiveness in reducing local emissions. An added benefit is that GTL can use existing infrastructure and requires no investment. Finally, the paper briefly discusses the coal to liquids (CTL) process as an alternative route to produce high quality GTL products and the key issues relating to the process. 展开更多
关键词 gas to liquids (GTL) coal to liquids (CTL) liquefied natural gas (LNG)
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Gel-state polybenzimidazole proton exchange membranes with flexible alkyl sulfonic acid side chains for a wider operating temperature range(25–240 ℃) 被引量:3
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作者 Taizhong Zhu Danyi Zhu +3 位作者 Jiazhen Liang Liang Zhang Fei Huang Lixin Xue 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第10期91-101,I0005,共12页
High-temperature proton exchange membrane fuel cells(HT-PEMFC) possess distinct technical advantages of high output power, simplified water/heat management, increased tolerance to fuel impurities and diverse fuel sour... High-temperature proton exchange membrane fuel cells(HT-PEMFC) possess distinct technical advantages of high output power, simplified water/heat management, increased tolerance to fuel impurities and diverse fuel sources, within the temperature range of 120–200 ℃. However, for practical automobile applications, it was crucial to broaden their low-temperature operating window and enable cold start-up capability. Herein, gel-state phosphoric acid(PA) doped sulfonated polybenzimidazole(PBI) proton exchange membranes(PEMs) were designed and synthesized via PPA sol-gel process and in-situ sultone ring-opening reactions with various proton transport pathways based on absorbed PA, flexible alkyl chain connected sulfonic acid groups and imidazole sites. The effects of flexible alkyl sulfonic acid side chain length and content on PA doping level, proton conductivity, and membrane stability under different temperature and relative humidity(RH) were thoroughly investigated. The prepared gel-state membranes contained a self-assembled lamellar and porous structure that facilitated the absorption of a large amount of PA with rapid proton transporting mechanisms. At room temperature, the optimized membrane exhibited a proton conductivity of 0.069 S cm^(-1), which was further increased to 0.162 and 0.358 S cm^(-1)at 80 and 200 ℃, respectively, without additional humidification. The most significant contribution of this work was demonstrating the feasibility of gel-state sulfonated PBI membranes in expanding HT-PEMFC application opportunities over a wider operating range of 25 to 240 ℃. 展开更多
关键词 Wide temperature range Proton exchange membrane Fuel cell Gel-state POLYBENZIMIDAZOLE
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Sr掺杂对La_(1-x)Sr_xMnO_3/LaAlO_3/SrTiO_3界面电子结构的影响 被引量:1
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作者 阮璐风 王磊 孙得彦 《物理学报》 SCIE EI CAS CSCD 北大核心 2017年第18期210-217,共8页
采用基于密度泛函理论的第一性原理计算方法,系统地研究了La_(1-x)Sr_xMnO_3层中Sr的掺杂方式和掺杂量对4La_(1-x)Sr_xMnO_3/3LaAlO_3/4SrTiO_3(LSMO/LAO/STO)异质结构原子和电子结构的影响.结果表明:对于相同的Sr掺杂量,掺杂方式的差... 采用基于密度泛函理论的第一性原理计算方法,系统地研究了La_(1-x)Sr_xMnO_3层中Sr的掺杂方式和掺杂量对4La_(1-x)Sr_xMnO_3/3LaAlO_3/4SrTiO_3(LSMO/LAO/STO)异质结构原子和电子结构的影响.结果表明:对于相同的Sr掺杂量,掺杂方式的差异对体系电子结构的影响微弱,不会导致体系发生金属-绝缘体转变;掺杂量的不同对体系电子结构有着显著的影响,当Sr的掺杂量较少时,LAO/STO界面处存在着准二维电子气,当Sr的掺杂量高于1/3时,LAO/STO界面处准二维电子气消失.我们相信,Sr的引入以及通过Sr掺杂量的改变可以对LSMO覆盖层极化进行调控,这也是导致体系LAO/STO界面处金属-绝缘体转变的可能原因,进一步为极化灾变机制导致的界面处电子重构提供了证据. 展开更多
关键词 第一性原理计算 氧化物异质结构 掺杂 准二维电子气
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Mechanisms involved in Korean mistletoe lectin-induced apoptosis of cancer cells 被引量:6
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作者 Lee-Yong Khil Wi Kim +3 位作者 Suyun Lyu Won Bong Park Ji-Won Yoon Hee-Sook Jun 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第20期2811-2818,共8页
AIM: To investigate the anti-cancer mechanisms of Korean mistletoe lectin (Viscum album coloratura agglutinin, VCA) using a human colon cancer cell line (COLO). METHODS: Cytotoxic effects of VCA on COLO cells we... AIM: To investigate the anti-cancer mechanisms of Korean mistletoe lectin (Viscum album coloratura agglutinin, VCA) using a human colon cancer cell line (COLO). METHODS: Cytotoxic effects of VCA on COLO cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTI-) assay in vitro and tumor-killing effects in vivo. To study the mechanisms involved, the expression of various pro-caspases, anti- apoptotic proteins, and death receptors was determined by western blot. To determine which death receptor is involved in VCA-induced apoptosis of COLO cells, cytotoxicity was examined by MTT assay after treatment with agonists or antagonists of death receptors. RESULTS: VCA killed COLO cells in a time- and dosedependent manner and induced complete regression of tumors in nude mice transplanted with COLO cells. Treatment of COLO cells with VCA activated caspase-2, -3, -8, and -9 and decreased expression of anti-apoptotic molecules including receptor interacting protein, nuclear factor-κB, X-linked inhibitor of apoptosis protein, and Akt/protein kinase B. We then examined the involvement of death receptors in VCA-induced apoptosis. Only tumor necrosis factor receptor 1, among the death receptors examined, was involved in apoptosis of COLO cells, evidenced by inhibition of VCA-induced apoptosis and decreased activation of caspases, particularly caspase-8, by tumor necrosis factor receptor 1 antagonizing antibody.CONCLUSION: VCA-induced apoptotic COLO cell death is due to the activation of caspases and inhibition of antiapoptotic proteins, in part through the tumor necrosis factor receptor 1 signaling pathway. 展开更多
关键词 Viscum album coloratum LECTIN Apoptosis Tumor necrosis factor receptor-i CASPASE Colon cancer
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China's Employment Situation and Policies(Excerpts) 被引量:1
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作者 Information Office of the State Council of the People’s Republic of China April 2004,Beijing 《China Population Today》 2004年第3期2-10,共9页
关键词 中国 劳动力就业 管理机制 政府职能
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Relationships between emissions of toxic airborne molecules and type 1 diabetes incidence in children:An ecologic study 被引量:1
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作者 Agostino Di Ciaula Piero Portincasa 《World Journal of Diabetes》 SCIE 2021年第5期673-684,共12页
BACKGROUND Type 1 diabetes originates from gene-environment interactions,with increasing incidence over time.AIM To identify correlates of childhood type 1 diabetes in European countries using an ecological approach.S... BACKGROUND Type 1 diabetes originates from gene-environment interactions,with increasing incidence over time.AIM To identify correlates of childhood type 1 diabetes in European countries using an ecological approach.Several environmental variables potentially influencing the onset of type 1 diabetes have been previously evaluated.However,the relationships between epidemiologic data and exposure to toxic airborne molecules are scarcely studied.METHODS We employed an ecological model to explore,in a wide time period(1990-2018),associations between type 1 diabetes incidence in 19 European countries(systematic literature review)and the nationwide production of five widely diffused air pollutants:particulate matter<10μm(PM10),nitrogen oxides(NO),non-methane volatile organic compounds(VOCs),sulphur oxide(SO2),and ammonia.RESULTS Data confirm a raising incidence of type 1 diabetes in 18 out of 19 explored countries.The average difference(last vs first report,all countries)was+6.9×100000/year,with values ranging from-1.4(Germany)to+16.6(Sweden)per 100000/year.Although the overall production of pollutants decreased progressively from 1990 to 2018,type 1 diabetes incidence was positively associated with the nationwide emissions of PM10,VOCs,and NO but not with those of SO2 and ammonia.Type 1 diabetes incidence was significantly higher in countries with high emissions than in those with low emissions of PM10(27.5±2.4 vs 14.6±2.4×100000 residents,respectively),VOCs(24.5±4.4 vs 13.2±1.7×100000 residents,respectively),and NO(26.6±3 vs 13.4±2.4×100000 residents,respectively),but not of SO2 or ammonia.CONCLUSION Evidence justify further studies to explore better links between long-term air quality and type 1 diabetes onset at the individual level,which should include exposures during pregnancy.In this respect,type 1 diabetes could be,at least in part,a preventable condition.Thus,primary prevention policies acting through a marked abatement of pollutant emissions might attenuate future type 1 diabetes incidence throughout Europe. 展开更多
关键词 Type 1 diabetes Epidemiology Air pollution Particulate matter Nitrogen oxide Non-methane volatile organic compounds
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Outcome of nonerosive gastro-esophageal reflux disease patients with pathological acid exposure 被引量:8
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作者 Fabio Pace Stefano Pallotta +7 位作者 Gianpiero Manes Annalisa de Leone Patrizia Zentilin Luigi Russo Vincenzo Savarino Matteo Neri Enzo Grossi Rosario Cuomo 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第45期5700-5705,共6页
AIM: To assess the management and outcome of nonerosive gastro-esophageal reflux disease (NERD) patients who were identified retrospectively, after a 5-year follow-up. METHODS: We included patients with gastro-eso... AIM: To assess the management and outcome of nonerosive gastro-esophageal reflux disease (NERD) patients who were identified retrospectively, after a 5-year follow-up. METHODS: We included patients with gastro-esophageal reflux disease (GERD) symptoms who had a negative endoscopy result and pathological 24-h esophageal pH-monitoring while off therapy. We interviewed them after an average period of 5 years (range 3.5-7 years) by means of a structured questionnaire to assess presence of GERD symptoms, related therapy, updated endoscopic data and other features. We assessed predictors of esophagitis development by means of univariate and multivariate statistical analysis. RESULTS: 260 patients (137 women) were included. Predominant GERD symptoms were heartburn and regurgitation in 103/260 (40%). 70% received a maintenance treatment, which was proton pump inhibitor (PPI) in 55% of cases. An average number of 1.5 symptomatic relapses per patient/year of follow-up were observed. A progression to erosive gastro-esophageal reflux disease (ERD) was found in 58/193 (30.0%) of patients undergoing repeat endoscopy; 72% of these were Los Angeles grade A-B. CONCLUSION: This study to ERD occurs in about 5% shows that progression of NERD cases per year, despite therapy. Only two factors consistently and independently influence progression: smoking and absence of PPI therapy. 展开更多
关键词 ESOPHAGUS Nonerosive gastro-esophageal reflux disease Gastro-esophageal reflux disease EPIDEMIOLOGY ACIDITY
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New Proposal of Evaluation of the Thoracic Outlet 被引量:1
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作者 Bordoni Bruno Marelli Fabiola +1 位作者 Morabito Bruno Sacconi Beatrice 《Open Journal of Therapy and Rehabilitation》 2018年第2期17-42,共26页
The present article comprehensively reviews the thoracic outlet syndrome (TOS), its etiology and assessment, with reference to the usual conservative treatment and surgical therapy, highlighting new definitions and re... The present article comprehensively reviews the thoracic outlet syndrome (TOS), its etiology and assessment, with reference to the usual conservative treatment and surgical therapy, highlighting new definitions and reporting obsolete tests. The syndrome affects about 8% of the population, with higher prevalence in females, and rarely affects the children. Conservative, non-surgical treatment produces good results, and it becomes important to know which specific areas need to be treated. Currently, there is no rehabilitation scheme, either osteopathic or chiropractic, considered as a valid tool for a precise localization of the pathologic condition, probably due to the lack of a manual assessment process to evaluate bones and muscular components of the thoracic outlet. In this situation, the manual treatment performed is usually generic. The present article proposes a manual evaluation that can be used to identify the anatomical area which needs to be treated. This hypothesis of assessment should be carried out after the clinician has ruled out the necessity of surgery with instrumental examinations. 展开更多
关键词 THORACIC OUTLET Syndrome Physiotherapy OSTEOPATHIC CHIROPRACTIC Pain Manual EVALUATION FASCIA
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Comparison of four clinical scores for the predicting lower limb deep venous thrombosis in Chinese patients 被引量:1
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作者 Li Zhu Min Liu +5 位作者 Xiaojuan Guo Jianguo Wang Youmin Guo Chen Wang Hongxia Ma Yulin Guo 《Journal of Nanjing Medical University》 2008年第4期230-233,共4页
Objective:To evaluate Wells, Kahn, St.Andr 6 and Constans scores for the prediction of deep venous thrombosis in Chinese patients. Methods:One hundred and seventy-two patients, prospectively, blinded referred for ev... Objective:To evaluate Wells, Kahn, St.Andr 6 and Constans scores for the prediction of deep venous thrombosis in Chinese patients. Methods:One hundred and seventy-two patients, prospectively, blinded referred for evaluation with four clinical-score systems for suspected deep venous thrombosis, were examined by ultrasonography. Sensitivity, specificity, positive predictive value, negative predictive value and receiver operation curves were calculated for four clinical scores. The difference between areas of the ROC curve for each of the scores was compared with others and reference line. Results:Forty-six of 172 patients had deep venous thrombosis proven by sonography. The sensitivity, specificity, positive predictive value and negative predictive value for Wells score was 91.3%, 57.1%, 43.8% and 94.7%, respectively, for Kahn score; 65.2%, 71.4%, 45.5% and 84.9%, respectively, for St.Andr 6 score; 63%, 38.9%, 27.4% and 74.2% respectively, for Constans score; 95.7%, 34.9%, 34.9% and 95.7% respectively. Area under ROV curve of Constans score was 0.814, which was similar to that of Wells score, then followed by Kahn score and that of St.Andr 6 score was no difference with the reference line. Conclusion:Based on the results of our study, the sensitivity, negative prediction value and area under ROC curve are larger for Constans score and Wells score in Chinese hospitalized patients than that of Kahn score or St.Andr 6 score. Considering the aim of the clinical assessment, Constans score and Wells score are more efficient for Chinese hospitalized patients. 展开更多
关键词 deep venous thrombosis clinical assessment lower extremity sonography
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Molecular memory of Flavescence dorée phytoplasma in recovering grapevines 被引量:1
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作者 Chiara Pagliarani Giorgio Gambino +6 位作者 Alessandra Ferrandino Walter Chitarra Urska Vrhovsek Dario Cantu Sabrina Palmano Cristina Marzachì Andrea Schubert 《Horticulture Research》 SCIE 2020年第1期1185-1199,共15页
Flavescence dorée(FD)is a destructive phytoplasma disease of European grapevines.Spontaneous and cultivardependent recovery(REC)may occur in the field in FD-infected vines starting the year following the first sy... Flavescence dorée(FD)is a destructive phytoplasma disease of European grapevines.Spontaneous and cultivardependent recovery(REC)may occur in the field in FD-infected vines starting the year following the first symptoms.However,the biological underpinnings of this process are still largely unexplored.In this study,transcriptome sequencing(RNAseq),whole-genome bisulphite sequencing(WGBS)and metabolite analysis were combined to dissect molecular and metabolic changes associated to FD and REC in leaf veins collected in the field from healthy(H),FD and REC plants of the highly susceptible Vitis vinifera‘Barbera’.Genes involved in flavonoid biosynthesis,carbohydrate metabolism and stress responses were overexpressed in FD conditions,whereas transcripts linked to hormone and stilbene metabolisms were upregulated in REC vines.Accumulation patterns of abscisic acid and stilbenoid compounds analysed in the same samples confirmed the RNAseq data.In recovery conditions,we also observed the persistence of some FD-induced expression changes concerning inhibition of photosynthetic processes and stress responses.Several differentially expressed genes tied to those pathways also underwent post-transcriptional regulation by microRNAs,as outlined by merging our transcriptomic data set with a previously conducted smallRNAseq analysis.Investigations by WGBS analysis also revealed different DNA methylation marks between REC and H leaves,occurring within the promoters of genes tied to photosynthesis and secondary metabolism.The results allowed us to advance the existence of a“molecular memory”of FDp infection,involving alterations in the DNA methylation status of REC plants potentially related to transcriptional reprogramming events,in turn triggering changes in hormonal and secondary metabolite profiles. 展开更多
关键词 METABOLISM alterations STARTING
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Comparison of Satellite and Ship Observations for Total Cloud Amount 被引量:1
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作者 章名立 Garrett G.Campbell 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1992年第1期63-72,共10页
The data series of monthly clouldiness over global ocean from COADS was compared with that of from satellite Nimbus-7 during April 1979 to March 1985. The correspondence between them is good. Both the two methods of o... The data series of monthly clouldiness over global ocean from COADS was compared with that of from satellite Nimbus-7 during April 1979 to March 1985. The correspondence between them is good. Both the two methods of observation can provide useful information of the distribution of cloudiness and the two data sets can be mutually complementary. 展开更多
关键词 Comparison of Satellite and Ship Observations for Total Cloud Amount
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超越画谜游戏?——精神分析与中国人的释梦 被引量:1
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作者 Dany Nobus 曾奇峰 《德国医学》 2001年第5期300-303,共4页
精神分析的诞生,是与1899年弗洛伊德的《释梦》的出版联系在一起的.弗洛伊德在1896年就介绍了“精神分析”这一术语,在《释梦》中,他第一次严格而系统地阐述了它的主要原则,还同时提供了他对梦的现象的新见解.他的前辈——他们要么认为... 精神分析的诞生,是与1899年弗洛伊德的《释梦》的出版联系在一起的.弗洛伊德在1896年就介绍了“精神分析”这一术语,在《释梦》中,他第一次严格而系统地阐述了它的主要原则,还同时提供了他对梦的现象的新见解.他的前辈——他们要么认为梦是表面的、毫无意义的副产品,要么认为梦是给做梦者关于其命运的神喻.不同的是,弗洛伊德证明,所有的梦都可以被看作是对做梦者醒时的被压制的潜意识愿望的满足.由无数图像组成的显梦(做梦者梦到了什么)是一系列潜在思想的伪装的表达.弗洛伊德认为,梦隐藏的意义可以通过特殊的分析技术加以揭示,这一技术可以解开梦的各种各样的形式. 展开更多
关键词 精神病学 精神分析 释梦 中国人
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Evaluation of stress concentration for planar tubular joints
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作者 M.F.GHANAMEH D.THE VENET A.ZEGHLOUL 《中国有色金属学会会刊:英文版》 CSCD 2006年第B01期1-10,共10页
In offshore tubular structures, a typical tubular joint may be subjected to three different types of basic loadings: axial, in-plane bending and out-of-plane bending, through its brace members. Each type will cause a ... In offshore tubular structures, a typical tubular joint may be subjected to three different types of basic loadings: axial, in-plane bending and out-of-plane bending, through its brace members. Each type will cause a different stress distribution at the joint intersection of structures. Moreover, the actual load condition of a tubular joint can be any combination of the above three basic load cases, for this reason, a combined loading was investigated in addition to these three basic loadings. This load is composed of an axial loading combined with a continuation of rotational bending loading obtained while rotate center of the brace around a circle. Different types of planar joints such as T, Y, X, K, DT, DY, DX, TY, TK, DTX, DTDY, and DTDK, with braces subjected to combined loading, were numerically analyzed to study the effect of those different cases of loading and different types of joints, on the stress concentration zone and values. 展开更多
关键词 管子接头 焊接 应力集中 评价 应力分布 有限元法 海洋平台
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Effects of cryogenic cold air jet cutting on chip break in metal machining
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作者 YANGYing TONGMingwei WUZhijuan 《Journal of Chongqing University》 CAS 2004年第1期6-10,共5页
The half-dry cutting employs cryogenic compressed air cooled down to (10 to 40) and a micro-dosage of lubricating oil, called cryogenic cold air jet cutting was studied. On the basis of a comparative experiment on dr... The half-dry cutting employs cryogenic compressed air cooled down to (10 to 40) and a micro-dosage of lubricating oil, called cryogenic cold air jet cutting was studied. On the basis of a comparative experiment on dry and cryogenic cold air jet cuttings carried out for grade 45 steel, the effects of cryogenic cold air jet on the breaking of chips were discussed. The experimental results reveal that in the valid ranges of pressure and temperature, the cryogenic cold air jet widens the chip breaking areas effectively. When the cutting depth is not greater than 1 mm, the influence of chip breaking is much more significant. But different injecting angle of cold air has different influence on the chip-break. From the experiment, the optimized jet injecting angle, temperature effecting range and pressure working range of cold air are obtained. These results can offer a foundation for industrial manufacturing. 展开更多
关键词 chip-break CUTTING cryogenic cold air jet
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Telecorrelation of the 500 hPa Polar Circulation and El Nino / SO with the Temperature Fields in China
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作者 施能 罗伯良 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1991年第3期289-298,共10页
By using the monthly data from 1951 through 1984, empirical orthogonal expansion is performed for the 500 hPa geopotential height north of 65°N and the canonical fields are clustered by fuzzy classification. It i... By using the monthly data from 1951 through 1984, empirical orthogonal expansion is performed for the 500 hPa geopotential height north of 65°N and the canonical fields are clustered by fuzzy classification. It is noted that both the mean monthly polar vortex fields and the large-scale anomaly fields fall into three regimes, with those of the January mean field and th April anomaly field having characteristic features. In addition, the relationship between the time weigthing coefficients of the canonical fields and El Nino / SO is examined, showing significant anomalies in the large-scale polar anomaly fields during April and October of the year when El Nino occurs. These polar circulation anomalies have considerably influenced the temperature fields in China during April and October. Thus, we may conclude that this is one of the most important reasons for a relatively cool April and a warm October in China during the El Nino year. 展开更多
关键词 SO with the Temperature Fields in China Telecorrelation of the 500 hPa Polar Circulation and El Nino El
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A linear rotary magnetorheological damper for vehicles
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作者 JIANGJiandong LIANGXichang ZHANGBo XIAOJunli 《Journal of Chongqing University》 CAS 2004年第1期11-15,共5页
A new type of linear rotary magnetorheological damper (MRD) is proposed, which consists of a cylinder-type MRD and a screw mechanism to transform a linear motion into revolving motion. It is found that the structure p... A new type of linear rotary magnetorheological damper (MRD) is proposed, which consists of a cylinder-type MRD and a screw mechanism to transform a linear motion into revolving motion. It is found that the structure parameters of MRD have complex relationship with the force of the damper, especially the lead angle, width and radius of the inner rotor. The analyses and simulation calculation of the static magnetic field give some usable data, and experiments of the damping component indicate that the proposed methods is feasible for developing linear rotary MRD. 展开更多
关键词 MR damper (MRD) screw mechanism automotive suspension
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INFLUENCES OF EDGING ROLL SHAPE ON THE PLASTIC STRAIN DISTRIBUTION OF SLAB DURING MULTI-PASS V-H ROLLING PROCESS
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作者 H.L. Yu X.H. Liu +2 位作者 C.S. Li X.M. Zhao Y. Kusaba 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2006年第1期51-56,共6页
Multi-pass slab vertical-horizontal (V-H) rolling process with variable edging roll shape have been simulated with explicit dynamic finite element method and updating geometric method. The distributions of plastic s... Multi-pass slab vertical-horizontal (V-H) rolling process with variable edging roll shape have been simulated with explicit dynamic finite element method and updating geometric method. The distributions of plastic strain contour in slab daring rolling process with different edging roll and under different rolling stage have been obtained. The results show that there exist two thin strain assembling zones in slab when the flat edging roll is used, and there just exist one strain assembling zone in slab when the edging roll with groove is used. And compared the deformation equality between flat edging roll and edging roll with groove, the lateris better than the former, which supplies the theory prove to the slab deformation distribution during V-H rolling process and is helpful for predicting the slab texture. 展开更多
关键词 strain V-H rolling MULTI-PASS finite element method (FEM) updating geometric method
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