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目的：观察针刺内关穴对宝石CT冠状动脉成像质量的影响。方法：将行宝石能谱CT冠状动脉造影检查心动过速及心律不齐的200 例患者作为研究对象,分为观察组和对照组,分别于检查前予针刺内关穴（双侧）、口服倍他乐克。比较2组心率以及冠状动脉CT血管成像（CTA）图像质量情况。结果：对照组心率下降例数少于观察组,无变化及心率上升例数多于观察组,组间比较,差异有统计学意义（P＜0.05）;观察组冠状动脉CTA图像质量［右冠状动脉（RCA）、左前降支（LAD）、左旋支（LCX）］明显优于对照组,差异具有统计学意义（P＜0.05）。结论：针刺内关穴可降低心动过速及心律不齐患者心率、调整心律,减少冠状动脉CTA成像血管伪影、错层等,能更好地显示冠状动脉斑块情况、狭窄程度,提高冠状动脉病变诊断的准确性。 相似文献
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目的：探讨采用冠状动脉结扎法建立大鼠心肌纤维化（Myocardial Fibrosis,MF）模型的方法,以期为临床防治MF提供实验基础。方法：术前进行包括对实验动物、药物、仪器和器械的准备;手术操作过程按照麻醉、消毒、连接呼吸机、心电图监测、开胸、结扎、关胸、脱机、术后处理的步骤;手术过程要求无菌操作,保护实验动物肺脏,观察其呼吸及恢复自主呼吸时间,注意结扎手法,预防感染。造模是否成功可通过HE染色观察心脏组织病理学变化、Masson染色显微镜下进行左室心肌胶原容积分数检测、心脏组织HYP、TGF-β1含量检测来确定。结论：规范冠状动脉结扎法建立大鼠MF模型的步骤,完善每个细节,对提高实验大鼠存活率及造模成功率具有重要的意义。 相似文献
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目的：采用Meta分析评价常规西药联合地奥心血康胶囊治疗冠状动脉粥样硬化性心脏病（CAD）的疗效和安全性。方法：检索中国知网（CNKI）、维普中文科技期刊数据库（VIP）、万方数据（WANFANG DATA）、中国生物医学文献服务系统（SinoMed）、PubMed、Embase和国内外临床试验注册中心,获得常规西药联合地奥心血康胶囊的随机对照试验（RCT）文献。有效性终点包括总有效率（TER）、左心室射血分数（VEF）、心输出量（CO）、心脏指数（CI）的改善情况和心绞痛发作持续时间,安全性终点包括不良事件（AEs）、主要心血管不良事件（MACEs）和死亡事件。本研究使用Cochrane偏倚风险评估工具和改良的Jadad量表评估了纳入研究的质量,并使用随机效应模型汇总数据。结果：纳入文献28篇。与西药治疗比较,合并地奥心血康胶囊治疗CAD可将TER提高20%［RR=1.20,95%CI（1.15,1.26）,P<0.00001］,并可显著改善CAD患者的LVEF［MD=8.10,95%CI（2.85,13.34）,P=0.02］、CO［MD=0.74,95%CI（0.58,0.89）,P<0.00001］、CI［MD=0.62,95%CI（0.30,0.94）,P=0.0002］。此外,这种联合治疗可降低AEs、MACEs和死亡事件的发生率,同时可缩短心绞痛发作持续时间。结论：与常规西药治疗相比,联合地奥心血康胶囊治疗方案能更有效地治疗CAD,并降低不良事件的发生。 相似文献
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目的：观察健脾化浊汤治疗冠心病合并脂肪肝脾虚痰瘀证的临床疗效。方法：将60例冠心病合并脂肪肝脾虚痰瘀证患者随机分为治疗组和对照组各30例。治疗组给予健脾化浊汤加西医常规治疗,对照组给予单纯西医常规治疗。观察2组的各方面疗效和相关指标的变化。结果：2组中医证候疗效、心绞痛疗效、心电图疗效比较,差异均有统计学意义（P＜0.05）。2组中医证候积分、肝脏彩超分级、血脂水平治疗前后组内比较及治疗后组间比较,差异均有统计学意义（P＜0.05）。结论：健脾化浊汤治疗冠心病合并脂肪肝脾虚痰瘀证,疗效显著,且未发现明显不良反应。 相似文献
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The traction capacity of the mining machine is greatly in?uenced by the traction rheological properties of the deep-sea sediments. The best simulative soil was prepared for substituting the deep-sea sediment based on the deep-sea sediment collected from the Paci?c C-C mining area. Traction rheological properties of the simulative soil were studied by a home-made test apparatus. In order to accurately describe the traction rheological properties and determine traction rheological parameters, the Newtonian dashpot in Maxwell body of Burgers model was replaced by a self-similarity spring-dashpot fractance and a new rheological constitutive model was deduced by fractional derivative theory. The results show the simulative soil has obvious non-attenuate rheological properties. The transient creep and stable creep rate increase with the traction, but they decrease with ground pressure. The fractional derivative Burgers model are better in describing non-attenuate rheological properties of the simulative soil than the classical Burgers model. For the new traction rheological constitutive equation of the simulative soil, the traction rheological parameters can be obtained by ?tting the tested traction creep data with the traction creep constitutive equation. The ground contact length of track and walking velocity of the mining machine predicted by the traction rheological constitutive equation can be used to take full advantages of the maximum traction provided by the soil and safely improve mining effciency. 相似文献
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中国沿海中华白海豚种群的分布区 总被引：1，自引：0，他引：1
中华白海豚Sousa chinensis(Osbeck,1765)首先在我国发现,是我国沿海仅有的定居性海洋鲸豚类.本文根据中华白海豚目击事件和研究报道,分析了中华白海豚在中国的分布、种群隔离及其差异.认为我国南方福建、广东以南沿海为中华白海豚种群的主要分布区,明确指出我国沿海存在5个主要的中华白海豚种群栖息地.通过分析,划分出中华白海豚活动的边缘区和栖息地两个部分.由于中华白海豚种群不断缩小,在保护中华白海豚栖息地的基础上,加强对中华白海豚栖息地外的边缘区的保护显得尤为重要.本文分析将为科学划定中华白海豚保护区提供依据. 相似文献
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Study of the Bearing Capacity at the Variable Cross-Section of A Riser-Surface Casing Composite Pile
Reducing the cost of offshore platform construction is an urgent issue for marginal oilfield development.The offshore oil well structure includes a riser and a surface casing.The riser,surface casing and oil well cement can be considered special variable cross-section piles.Replacing or partially replacing the steel pipe pile foundation with a variable cross-section pile to provide the required bearing capacity for an offshore oil platform can reduce the cost of foundation construction and improve the economic efficiency of production.In this paper,the finite element analysis method is used to investigate the variable cross-section bearing mode of composite piles composed of a riser and a surface casing in saturated clay under a vertical load.The calculation formula of the bearing capacity at the variable section is derived based on the theory of spherical cavity expansion,the influencing factors of the bearing capacity coefficient Nc are revealed,and the calculation method of Nc is proposed.By comparing the calculation results with the results of the centrifuge test,the accuracy and applicability of the calculation method are verified.The results show that the riser composite pile has a rigid core in the soil under the variable cross-section,which increases the bearing capacity at the variable cross-section. 相似文献
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LIU Xiu-quan JIANG Yong LIU Fu-lai LIU Zhao-wei CHANG Yuan-jiang CHEN Guo-ming 《中国海洋工程》2021,(1):153-158
Vortex induced vibration(VIV)is a challenge in ocean engineering.Several devices including fairings have been designed to suppress VIV.However,how to optimize the design of suppression devices is still a problem to be solved.In this paper,an optimization design methodology is presented based on data-driven models and genetic algorithm(GA).Data-driven models are introduced to substitute complex physics-based equations.GA is used to rapidly search for the optimal suppression device from all possible solutions.Taking fairings as example,VIV response database for different fairings is established based on parameterized models in which model sections of fairings are controlled by several control points and Bezier curves.Then a data-driven model,which can predict the VIV response of fairings with different sections accurately and efficiently,is trained through BP neural network.Finally,a comprehensive optimization method and process is proposed based on GA and the data-driven model.The proposed method is demonstrated by its application to a case.It turns out that the proposed method can perform the optimization design of fairings effectively.VIV can be reduced obviously through the optimization design. 相似文献
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Lee Minji Kim Jin Ho Kim Yun-Bae Park Chan Hong Shin Kyoungsoon Baek Seung Ho 《海洋学报(英文版)》2020,39(2):107-122
The East Sea(Sea of Japan)is a marginal,semi-closed sea in the northwestern Pacific.The Ulleung Basin area,which is located near the subpolar front of the East Sea,is known to have high primary production and good fisheries in spring season.After episodic wind-driven events during the spring of 2017,horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin area.In addition,growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton biomass.Because of strong northwestern wind,phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this season.The phytoplankton abundances in the coastal stations were significantly higher than offshore and island stations.In contrast,the nutrient and chlorophyll a(Chl a)concentrations and the phytoplankton biomass were quite low in all locations.Bacillariophyceae was dominated group(>75.1%for coastal,40.0%for offshore and 43.6%for island stations).In the algal bioassays,the phytoplankton production was stimulated by N availability.The in vivo Chl a values in the+N and+NP treatments were significantly higher than the values in the control and the+P treatments.Based on the field survey,the higher nutrients in coastal waters affected the growth of diatom assemblages,however,little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay experiments.The growth of phytoplankton depended on the initial cell density.All of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers,and the low level of biomass supply from the coasts resulted in low primary production.Both supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea. 相似文献
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Maternal eff ects are one of the most interesting topics in evolutionary ecology as they can aff ect the rate of evolution and population dynamics by phenotypic manipulation of off spring related to fi tness. At present, studies examining the interaction between maternal environment eff ects and maternal age (birth order) eff ects are scarce. We designed an experiment to reveal whether environmentally induced maternal manipulation works equally on off spring across birth orders in rotifer Brachionus calycifl orus. In the experiment, newborn amictic mothers (F0) were cultured parallelly in low (LD) and high (HD) population density. Off spring (F1) of young (YF0) and old (OF0) mothers in both LD and HD groups were cultured under a crowded condition and the mixis ratios of both F1 and F2 were examined. Results show that F1 from HD-YF0 had a signifi cantly higher mixis ratio and those amictic ones produced daughters (F2 ) with higher mixis ratio in response to crowding than those from HD-OF0. In contrast, no such diff erences among F1 siblings were found in the LD-F0 group. Therefore, the eff ect of maternal age on the sexual propensity of the off spring can be aff ected independently by the maternal population density. 相似文献
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江苏盐城自然保护区核心区环境动态的遥感分析 总被引：1，自引：1，他引：1
根据江苏盐城自然保护区核心区两个时相陆地卫星影像资料的分析和对比,研究了 10 a 内核心区的植被演替、人工开发及潮沟系统演化,探讨自然及人为因素对整个原生湿地生态系统的影响.分析结果表明,互花米草滩的面积 10 a 间扩展了 10 倍以上,而作为珍禽的主要栖息地的盐蒿滩、草滩和芦苇滩的面积 10 a 内均有所下降,其中草滩面积的下降尤为明显.10 a 间芦苇田和水禽湖这两种人工湿地的面积增长显著.潮沟系统呈减少和萎缩趋势,在一定程度上是海岸开发活动和互花米草盐沼扩展的结果.保护区核心区的原生生态系统已有退化迹象,珍禽的原生栖息地的面积有所下降,因此建议保护区将工作重点放在保护和重建原生湿地上. 相似文献
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席薇亚·厄尔,于1935年8月30日出生于新泽西的吉布斯汤。她被《纽约客》和《纽约时报》称为深海女王,被美国国会图书馆称为活生生的传奇人物,更被时代周刊誉为地球的英雄。她是一位海洋学家、探险家、作家以及深入的致力于通过个人探索而进行研究的学者。 相似文献
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0418号台风"艾利"路径转折的多普勒速度特征模拟分析 总被引：1，自引：0，他引：1
2004年18号热带风暴"艾利"在移动过程中先后发生两次转折,这种路径在历史上极为罕见.本文重点分析了"艾利"台风在靠近福建东部海岸线发生第二次转折时的多普勒速度特征,并与多普勒正负速度区的对称性及极值变化的模拟结果进行比较,说明了通过对多普勒正负极值区变化的分析可以判断环境风的风向,进而判断台风未来的走向,且环境风风向的变化对于台风未来移向变化的影响有1～2 h的提前量.这有助于我们提高预报时效,对台风的预报有一定的指导意义. 相似文献
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Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats. 相似文献
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尽管古塞夫环形山(Gusev Crater)和子午线平原(Meridiani Planum)相距数千公里,但已经证实:来自两地的火星土壤有些成分极其相似,均富含氯和硫磺.最近,高精度的测量结果显示:地球所有已知生命的重要能量载体磷,同样丰富地存在于这些大片的火星土壤中.根据发表在2006年第11期《地质学》(Geology)杂志上的一篇新论文的观点,完全不同的地方却拥有如此类似的土壤,对此惟一的解释是:火星上曾存在面积巨大的酸性海洋. 相似文献
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在参加国际“Inter Margins”计划的匡架内,美国学者在2004年夏季详细研究了位于马利亚纳岛弧西北岸边的罗塔海底活火山。太平洋的这个海区不仅因为该区海底发生着强烈的气体、气液和熔岩喷发,并且以其对研究裂谷生成过程的重要性而具有重要意义。纽约州哥伦比亚大学拉蒙物·多 相似文献