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Timing and Spectral Analysis of 4U 1626-67 Using Astro Sat/LAXPC
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作者 N.J.Juris Marykutty James Jincy Devasia 《Research in Astronomy and Astrophysics》 2025年第5期47-57,共11页
We present a comprehensive analysis of AstroSat/LAXPC data of the second spin-up and second spin-down phases of the persistent X-ray pulsar 4U 1626-67.Flares followed by a broad dip are detected in the spin-up observa... We present a comprehensive analysis of AstroSat/LAXPC data of the second spin-up and second spin-down phases of the persistent X-ray pulsar 4U 1626-67.Flares followed by a broad dip are detected in the spin-up observations.The pulse profiles changed from a shoulder-like structure to a broad sinusoidal shape as the source underwent a torque reversal from spin-up to spin-down.Energy-resolved pulse profiles in lower energies showed a double-horned profile in the spin-up state and a flat top with multiple peaks in the spin-down state.Regardless of the torque state,the pulse profiles exhibit a broad single-peaked shape at higher energies.The observation in the spin-down era is characterized by the presence of a prominent QPO at 46.5±1.0 mHz frequency.The QPO rms and center frequency show a correlation with energy.Spin-up and spin-down states show a difference in the shape of the power density spectrum.After the torque reversal,a gradual flux drop and the hardening of the spectra were observed.The difference in the shape of the pulse profiles and the presence and absence of QPOs can be explained by the change in accretion flow geometry of the pulsar,from pencil-beam to fan-beam,between spin-down and spin-up states. 展开更多
关键词 (stars )pulsars individual(4U 1626-67)-X-rays binaries-X-rays general
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New unloading criterion for enhancing multi-stage triaxial tests based on radial strain gradient
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作者 Guodong Jin Shujath Ali Syed +3 位作者 Héctor JoséGonzález-Pérez Hyung Tae Kwak Ali Abdullah Yousef Ali Abdullah Al Dhamen 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第8期4735-4744,共10页
This paper presents a new criterion for determining the unloading points quantitatively and consistently in a multi-stage triaxial test.The radial strain gradient(RSG)is first introduced as an arc tangent function of ... This paper presents a new criterion for determining the unloading points quantitatively and consistently in a multi-stage triaxial test.The radial strain gradient(RSG)is first introduced as an arc tangent function of the rate of change of radial strain to time.RSG is observed to correlate closely with the stress state of a compressed sample,and reaches a horizontal asymptote as approaching failure.For a given rock type,RSG value at peak stress is almost the same,irrespective of the porosity and permeability.These findings lead to the development of RSG criterion:Unloading points can be precisely determined at the time when RSG reaches a pre-determined value that is a little smaller than or equal to the RSG at peak stress.The RSG criterion is validated against other criteria and the single-stage triaxial test on various types of rocks.Failure envelopes from the RSG criterion match well with those from single-stage tests.A practical procedure is recommended to use the RSG criterion:an unconfined compression or single-stage test is first conducted to determine the RSG at peak stress for one sample,the unloading point is then selected to be a value close to the RSG at peak stress,and the multi-stage test is finally performed on another sample using the pre-selected RSG unloading criterion.Generally,the RSG criterion is applicable for any type of rocks,especially brittle rocks,where other criteria are not suitable.Further,it can be practically implemented on the most available rock mechanical testing instruments. 展开更多
关键词 Radial strain gradient Unloading criterion Multi-stage triaxial test Mohr-coulomb failure envelope
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Diabetes in adolescents without obesity in India:An underrecognized phe
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作者 Rashi Agrawal Akhila Bhandarkar Nitin Kapoor 《World Journal of Clinical Pediatrics》 2025年第4期537-541,共5页
Adolescent type 2 diabetes mellitus(T2DM)is on the rise in India and is commonly attributed to co-existence of overweight and obesity in adolescents.In this line,a study by Maheshwari et al titled‘Prevalence of obesi... Adolescent type 2 diabetes mellitus(T2DM)is on the rise in India and is commonly attributed to co-existence of overweight and obesity in adolescents.In this line,a study by Maheshwari et al titled‘Prevalence of obesity,determinants,and its association with hyperglycaemia among community dwelling older adolescents in India’concluded that overweight,obesity,socioeconomic factors and higher education status were responsible for hyperglycemia in adolescents aged 15-19 years in India.We highlight that there is a significant prevalence of T2DM even in normal body mass index(BMI)and below normal BMI subjects,as mentioned in their study.There is a high prevalence of normal weight obesity in Indian adolescents which often gets missed due to a large population with normal BMI in the country.In this letter,we analyze the importance of measurement of central adiposity beyond routine BMI measurements. 展开更多
关键词 Normal weight obesity Adolescents Body mass index Metabolic syndrome Body composition Visceral fat Cardiometabolic risk
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Effort minimization:A permanent,dynamic,and surmountable influence on physical activity
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作者 Silvio Maltagliati Layan Fessler +7 位作者 Qian Yu Zhihao Zhang Yanxia Chen Olivier Dupuy Ryan SFalck Neville Owen Liye Zou Boris Cheval 《Journal of Sport and Health Science》 2025年第4期43-47,共5页
Today, most people know that physical activity(PA) is beneficial for their health ^(1,2)and aspire to engage in regular PA.^(3,4)However, despite their awareness of the importance of PA, it is evident that the transit... Today, most people know that physical activity(PA) is beneficial for their health ^(1,2)and aspire to engage in regular PA.^(3,4)However, despite their awareness of the importance of PA, it is evident that the transition from intention to action is challenging-a situation that has important public health implications. According to the World Health Organization,^(5)1 person dies every 6 s worldwide from causes related to physical inactivity, which underscores the urgency of addressing this situation. 展开更多
关键词 World Health Organization physical activity pa effort minimization intention action public health physical inactivity physical activity
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Reduced PI3K(p110α)induces atrial myopathy,and PI3K-related lipids are dysregulated in athletes with atrial fibrillation
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作者 Sebastian Bass-Stringer Bianca C.Bernardo +30 位作者 Gunes S.Yildiz Aya Matsumoto Helen Kiriazis Claudia A.Harmawan Celeste M.K.Tai Roger Chooi Lauren Bottrell Martin Ezeani Daniel G.Donner Aascha A.D'Elia Jenny Y.Y.Ooi Natalie A.Mellett Jieting Luo Emma I.Masterman Kristel Janssens Gavriel Olshansky Erin J.Howden Jonathon H.Cross Christoph E.Hagemeyer Ruby C.Y.Lin Colleen J.Thomas Graham W.Magor Andrew C.Perkins Thomas H.Marwick Hiroshi Kawakami Peter J.Meikle David W.Greening Kate L.Weeks AndréLa Gerche Yow Keat Tham Julie R.McMullen 《Journal of Sport and Health Science》 2025年第5期1-18,共18页
Background:Elucidating mechanisms underlying atrial myopathy,which predisposes individuals to atrial fibrillation(AF),will be critical for preventing/treating AF.In a serendipitous discovery,we identified atrial enlar... Background:Elucidating mechanisms underlying atrial myopathy,which predisposes individuals to atrial fibrillation(AF),will be critical for preventing/treating AF.In a serendipitous discovery,we identified atrial enlargement,fibrosis,and thrombi in mice with reduced phosphoinositide 3-kinase(PI3K)in cardiomyocytes.PI3K(p110a)is elevated in the heart with exercise and is critical for exercise-induced ventricular enlargement and protection,but the role in the atria was unknown.Physical inactivity and extreme endurance exercise can increase AF risk.Therefore,our objective was to investigate whether too little and/or too much PI3K alone induces cardiac pathology.Methods:New cardiomyocyte-specific transgenic mice with increased or decreased PI3K(p110a)activity were generated.Multi-omics was conducted in mouse atrial tissue,and lipidomics in human plasma.Results:Elevated PI3K led to an increase in heart size with preserved/enhanced function.Reduced PI3K led to atrial dysfunction,fibrosis,arrhythmia,increased susceptibility to atrial enlargement and thrombi,and dysregulation of monosialodihexosylganglioside(GM3),a lipid that regulates insulin-like growth factor-1(IGF1)-PI3K signaling.Proteomic profiling identified distinct signatures and signaling networks acrossatria with varying degrees of dysfunction,enlargement,and thrombi,including commonalities with the human AF proteome.PI3K-related lipids were dysregulated in plasma from athletes with AF.Conclusion:PI3K(p110a)is a critical regulator of atrial biology and function in mice.This work provides a proteomic resource of candidates for further validation as potential new drug targets and biomarkers for atrial myopathy.Further investigation of PI3K-related lipids as markers for identifying individuals at risk of AF is warranted.Dysregulation of PI3K may contribute to the association between increased cardiac risk with physical inactivity and extreme endurance exercise. 展开更多
关键词 Atrial myopathy ATRIALFIBRILLATION LIPIDOMICS Proteomics Exercise
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Arrhythmias and structural remodeling in lifelong and retired master endurance athletes
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作者 Paolo D'Ambrosio Jarne De Paepe +15 位作者 Kristel Janssens Amy M.Mitchell Stephanie J.Rowe Luke W.Spencer Tim Van Puyvelde Jan Bogaert Olivier Ghekiere Rik Pauwels Lieven Herbots Tomas Robyns Peter M.Kistler Jonathan M.Kalman Hein Heidbuchel Rik Willems Guido Claessen AndréLa Gerche 《Journal of Sport and Health Science》 2025年第5期19-30,共12页
Background:A greater prevalence of arrhythmias has been described in endurance athletes,but it remains unclear whether this risk persists after detraining.We aimed to evaluate the prevalence of arrhythmias and their r... Background:A greater prevalence of arrhythmias has been described in endurance athletes,but it remains unclear whether this risk persists after detraining.We aimed to evaluate the prevalence of arrhythmias and their relationship with cardiac remodeling in lifelong and retired master endurance athletes compared to non-athletic controls.Methods:We performed a cross-sectional analysis of observational studies that used echocardiography and cardiac magnetic resonance to detail cardiac structure and function,and Holter monitors to identify atrial and ventricular arrhythmias in 185 endurance athletes and 81 non-athletic controls aged≥40 years.Athletes were categorized as active lifelong(n=144)or retired(n=41)based on hours per week of high-intensity endurance exercise within 5 years of enrollment and validated by percentage of predicted maximal oxygen consumption(VO_(2max)).Athletes with overt cardiomyopathies,channelopathies,pre-excitation,and/or myocardial infarction were excluded.Results:Lifelong athletes(median age=55 years(interquartile range(IQR):46-62),79%male)were significantly fitter than retired athletes(median age=66 years(IQR:58-71),95%male)and controls(median age=53 years(IQR:48-60),96%male),respectively(predicted VO_(2max):131%±18%vs.99%±14%vs.98%±15%,p<0.001).Compared to controls,athletes in our cohort had a higher prevalence of atrial fibrillation((AF):32%vs.0%,p<0.001)and non-sustained ventricular tachycardia((NSVT):9%vs.1%,p=0.007).There was no difference in prevalence of any arrhythmia between lifelong and retired athletes.Lifelong athletes had larger ventricular volumes than retired athletes,who had ventricular volumes similar to controls(left ventricular end-diastolic volume indexed to body surface area(LVEDVi):101±20 m L/m^(2)vs.86±16 mL/m^(2)vs.94±18 mL/m^(2),p<0.001;right ventricular end-diastolic volume indexed to body surface area(RVEDVi):117±23 mL/m^(2)vs.101±19 mL/m^(2)vs.100±19 mL/m^(2),p<0.001).Athletes had more scar(40%vs.18%,p=0.002)and larger left atria(median volume=45m L/m^(2)(IQR:38-52)vs.31 mL/m^(2)(IQR:25-38),p<0.001)than controls,with no difference in atrial volumes and non-ischaemic scar between the athlete groups.Conclusion:Master endurance athletes have a higher prevalence of AF and NSVT than non-athletic controls.Whereas ventricular remodeling tends to reverse with detraining,the propensity to arrhythmias persists regardless of whether they are actively exercising or retired. 展开更多
关键词 ATHLETES ARRHYTHMIAS Atrial fibrillation Non-sustained ventricular tachycardia DETRAINING
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Decorin, an exercise-induced secretory protein, is associated with improved prognosis in breast cancer patients but does not mediate anti-tumorigenic tissue crosstalk in mice
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作者 Marit Hjorth Casey L.Egan +28 位作者 Guilherme D.Telles Martin Pal David Gallego-Ortega Oliver K.Fuller Emma D.McLennan Ryan D.Gillis Tae Gyu Oh George E.O.Muscat Surafel Tegegne Michael S.M.Mah Joanna Skhinas Emma Estevez Timothy E.Adams Matthew J.McKay Mark Molloy Kevin I.Watt Hongwei Qian Paul Gregorevic Thomas R.Cox Pernille Hojman Julie Midtgaard Jesper F.Christensen Martin Friedrichsen Renato V.Iozzo Erica K.Sloan Brian G.Drew Jørgen F.P.Wojtaszewski Martin Whitham Mark A.Febbraio 《Journal of Sport and Health Science》 2025年第3期55-72,共18页
Purpose:Regular exercise can reduce incidence and progression of breast cancer,but the mechanisms for such effects are not fully understood.The purpose of this study was to examine the mechanisms behind the protective... Purpose:Regular exercise can reduce incidence and progression of breast cancer,but the mechanisms for such effects are not fully understood.The purpose of this study was to examine the mechanisms behind the protective effects of exercise.Methods:We used a variety of rodent and human experimental model systems to determine whether exercise training can reduce tumor burden in breast cancer and to identify mechanism associated with any exercise training effects on tumor burden.Results:We show that voluntary wheel running slows tumor development in the mammary specific polyomavirus middle T antigen overexpression(MMTV-PyMT)mouse model of breast cancer but only when mice are not housed alone.We identify the proteoglycan decorin as a contraction-induced secretory factor that systemically increases in patients with breast cancer immediately following exercise.Moreover,high expression of decorin in tumors is associated with improved prognosis in patients,while treatment of breast cancer cells in vitro with decorin reduces cell proliferation.Notwithstanding,when we overexpressed decorin in murine muscle or injected recombinant decorin systemically into mouse models of breast cancer,elevated plasma decorin concentrations did not result in higher tumor decorin levels and tumor burden was not improved.Conclusion:Exercise training is anti-tumorigenic in a mouse model of luminal breast cancer,but the effect is abrogated by social isolation.The proteoglycan decorin is an exercise-induced secretory protein,and tumor decorin levels are positively associated with improved prognosis in patients.The hypothesis that elevated plasma decorin is a mechanism by which exercise training improves breast cancer progression in humans is not,however,supported by our pre-clinical data since elevated circulating decorin did not increase tumor decorin levels in these models. 展开更多
关键词 Breast cancer Exercise training Muscle secretory factors PROTEOGLYCANS
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智能钻井系统在赵东油田的应用 被引量:6
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作者 王贺强 郭海涛 +4 位作者 马翠岩 王子毓 陈友军 李斌 梁毅 《世界石油工业》 2024年第3期59-67,共9页
赵东油田开发后期调整井钻井施工中,需要进行三维防碰绕障,井眼轨道设计复杂,钻进过程中经常出现摩阻扭矩变化大、井眼清洁困难、井壁稳定性差、钻井液漏失等难题。针对精细化井眼轨迹控制和快速识别井下复杂状况等关键技术难点,采取以... 赵东油田开发后期调整井钻井施工中,需要进行三维防碰绕障,井眼轨道设计复杂,钻进过程中经常出现摩阻扭矩变化大、井眼清洁困难、井壁稳定性差、钻井液漏失等难题。针对精细化井眼轨迹控制和快速识别井下复杂状况等关键技术难点,采取以现场作业人员经验为主、智能钻井系统为辅的作业模式,通过贝克休斯智能钻井系统i-Trak™的量化分析与及时预警,提高了轨迹控制精度及井下复杂状况早发现、早调整的及时性,避免复杂工况的发生,降低非生产作业时间,缩短了建井周期。通过17口井的试验,进一步验证现场“作业人员经验+智能钻井系统”的作业模式能够很好满足安全高效钻井的需求,为海上油田开发后期复杂调整井的钻井施工提供了可借鉴经验。 展开更多
关键词 智能钻井 自动轨迹控制 摩阻扭矩 井眼清洁 赵东油田
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International norms for adult handgrip strength:A systematic review of data on 2.4 million adults aged 20 to 100+years from 69 countries and regions
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作者 Grant R.Tomkinson Justin J.Lang +15 位作者 Lukás Rubín Ryan McGrath Bethany Gower Terry Boyle Marilyn GKlug Alexandra JMayhew Henry T.Blake Francisco B.Ortega Cristina Cadenas-Sanchez Costan G.Magnussen Brooklyn J.Fraser Tetsuhiro Kidokoro Yang Liu Kaare Christensen Darryl P.Leong the iGRIPS(international handGRIP Strength)Group 《Journal of Sport and Health Science》 2025年第4期64-80,共17页
Background:Muscular strength is a powerful marker of current health status and robust predictor of age-related disease and disability.Handgrip strength(HGS)using isometric dynamometry is a convenient,feasible,and wide... Background:Muscular strength is a powerful marker of current health status and robust predictor of age-related disease and disability.Handgrip strength(HGS)using isometric dynamometry is a convenient,feasible,and widely used method of assessing muscular strength among people of all ages.While adult HGS norms have been published for many countries,no study has yet synthesized available data to produce international norms.The objective of this study was to generate international sex-and age-specific norms for absolute and body size-normalized HGS across the adult lifespan.Methods:Systematic searches were conducted in 6 databases/web search engines(MEDLINE,SPORTDiscus,Embase,Web of Science,CINAHL,and Google Scholar)up to December 1,2023.We included full-text peer-reviewed observational studies that reported normative HGS data for adults aged ≥20 years by sex and age.Pseudo data were generated using Monte Carlo simulation following harmonization for methodo-logical variation.Population-weighted Generalized Additive Models for Location,Scale,and Shape were used to develop sex-and age-specific norms for absolute HGS(kg)and HGS normalized by height(Ht,m)squared(i.e.,HGS/Ht^(2)in kg/m^(2)).Norms were tabulated as percentile values(5th to 95th)and visualized as smoothed percentile curves.Results:We included data from 100 unique observational studies representing 2,405,863 adults(51.9%female)aged 20 to 100+years from 69 countries and regions tested from the year 2000 onward.On average,absolute and normalized HGS values negligibly improved throughout early adulthood,peaked from age 3039 years(at 49.7 kg(males)and 29.7 kg(females)for absolute HGS or 16.3 kg/m^(2)(males)and 11.3 kg/m^(2)(females)for HGS/Ht^(2)),and declined afterwards.The age-related decline in HGS accelerated from middle to late adulthood and was slightly larger for males than for females during middle adulthood.Conclusion:This study provides the world’s largest and most geographically comprehensive international norms for adult HGS by sex and age.These norms have utility for global peer-comparisons,health screening,and surveillance. 展开更多
关键词 ADULT Reference values Hand strength Mass screening Population health
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数字金融如何影响制造业产业集聚?——兼论不同城市群的异质性影响分析
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作者 董良 李文瑞 +2 位作者 陈铮 李晶晶 胡晓刚 《金融经济》 2024年第8期67-78,共12页
制造业产业集群的构建对提高生产效率、带动区域经济增长具有重要意义,而数字金融通过推动“数字产业化”和“产业数字化”融合发展,深刻改变了制造业的组织架构和运行方式。本文从城市群视角出发,基于京津冀、珠三角、长三角、长江中... 制造业产业集群的构建对提高生产效率、带动区域经济增长具有重要意义,而数字金融通过推动“数字产业化”和“产业数字化”融合发展,深刻改变了制造业的组织架构和运行方式。本文从城市群视角出发,基于京津冀、珠三角、长三角、长江中游、成渝五大城市群2011—2019年的数据探讨数字金融对制造业集聚的影响。研究发现数字金融对制造业集聚有显著的正向影响,这种影响存在维度异质性,即其促进作用主要来源于数字金融覆盖广度的扩展,且数字金融对不同城市群的影响存在异质性。区域技术创新能力的提升和地区人力资本水平的提高在数字金融促进制造业产业集聚的过程中发挥着中介效应。本文依据实证结果提出各地区应根据当地经济发展情况制定相应的数字金融发展政策、实行区域发展协调战略等政策建议,以实现数字金融与实体经济的深度融合。 展开更多
关键词 数字金融 制造业集聚 城市群 技术创新 人力资本 区域协调发展
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路基粒状填土的旋转压实试验 被引量:4
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作者 邹维列 王钊 杨志强 《岩土力学》 EI CAS CSCD 北大核心 2004年第11期1775-1778,共4页
尽管击实试验是目前最流行的室内土体压实试验方法,但实际上与现场任何一种压实方法都无相似之处,且不适用于无粘性土(粒状土)的压实试验。无粘性土的振动击实试验方法也存在很多问题。现代重型压实设备的使用,路基粒状填土的压实密度... 尽管击实试验是目前最流行的室内土体压实试验方法,但实际上与现场任何一种压实方法都无相似之处,且不适用于无粘性土(粒状土)的压实试验。无粘性土的振动击实试验方法也存在很多问题。现代重型压实设备的使用,路基粒状填土的压实密度达到了目前室内规范试验方法不可能达到的水平。介绍了美国采用供高性能沥青路面混合料设计与质量控制之用的旋转压实机对粒状土进行的压实试验。其结果表明,旋转压实试验能有效模拟路基粒状填土的现场压实特征;可采用压实压力200 kPa、旋转角为1.25°、旋转次数为90、旋转速度为20 rpm的试验结果来控制粒状填土路基的现场压实质量。 展开更多
关键词 粒状土 击实试验 振动压实试验 旋转压实试验
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后适应缺血时间窗的选择对小鼠心肌再灌注损伤的影响 被引量:4
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作者 张健发 马依彤 +5 位作者 杨毅宁 高晓明 刘芬 陈邦党 李晓梅 向阳 《中国实验动物学报》 CAS CSCD 2008年第2期127-131,共5页
目的探讨后适应对小鼠心肌再灌注损伤的影响以及不同缺血时间窗的后适应心脏保护作用的差异。方法96只成年C57/BL小鼠随机分为缺血时间30、45min和60min的三组,每组又分为后适应和缺血再灌注两种处理。通过开胸结扎左冠状动脉造成急性... 目的探讨后适应对小鼠心肌再灌注损伤的影响以及不同缺血时间窗的后适应心脏保护作用的差异。方法96只成年C57/BL小鼠随机分为缺血时间30、45min和60min的三组,每组又分为后适应和缺血再灌注两种处理。通过开胸结扎左冠状动脉造成急性心肌梗死,在完全再灌注早期给予反复短暂再通/闭塞的缺血后适应。采用Evansblue和TTC染色的方法确定缺血心肌和梗死心肌面积,并测定血清的心肌酶含量、心肌超氧化物歧化酶(SOD)活性与丙二醛(MDA)水平以及血流动力学指标。结果缺血30min后适应组、缺血45min后适应组心肌梗死面积分别比相同缺血时间的再灌注对照组减少53.1%和31.2%,差异均具有统计学意义(P<0.01),缺血后适应可明显降低血清心肌酶、提高心肌SOD的活性以及改善血流动力学的恶化;缺血60min后适应组梗死心肌面积无明显降低,差异无统计学意义(P>0.05)。结论小鼠心肌处于轻中度水平的缺血损伤,在恢复冠脉血流的早期施行缺血后适应可以有效地减少心肌再灌注损伤,但随着缺血时间的延长,心肌保护作用就明显减弱或消失。 展开更多
关键词 缺血时间窗 缺血后适应 再灌注损伤 小鼠心肌
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小鼠主动脉弓缩窄模型的建立及评价 被引量:19
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作者 李晓梅 马依彤 +4 位作者 杨毅宁 高晓明 刘芬 韩伟 张健发 《中国比较医学杂志》 CAS 2008年第11期24-29,86,共7页
目的通过显微外科技术建立小鼠主动脉弓缩窄压力超负荷模型,探讨心脏形态及功能变化的规律。方法135只雄性昆明小鼠随机分为主动脉弓缩窄组75只和假手术组60只。在术前、术后1周、4周、6周、8周1、2周进行高频心脏超声、血流动力学、心... 目的通过显微外科技术建立小鼠主动脉弓缩窄压力超负荷模型,探讨心脏形态及功能变化的规律。方法135只雄性昆明小鼠随机分为主动脉弓缩窄组75只和假手术组60只。在术前、术后1周、4周、6周、8周1、2周进行高频心脏超声、血流动力学、心脏病理学检测,并对器官称重,对死亡原因进行分析。结果(1)主动脉弓缩窄手术成功率为88%;(2)与假手术组比较,术后4周,缩窄组小鼠出现左室向心性肥厚,左心室收缩期、舒张期后壁厚度(Pwsth;Pwdth)、左心室重量指数(LVMI)显著增加(P<0.05),术后6、8、12周上述指标呈轻度上升趋势;术后4、68、、12周,缩窄组小鼠动脉收缩压(SBP)、动脉舒张压(DBP)、左心室收缩压(LVSP)、左心室舒张末压(LVEDP)显著增加(P<0.05);术后8周,缩窄组小鼠表现为离心性肥厚,左心室收缩末期、舒张末期内径(LVESd;LVEDd)显著增加(P<0.05);术后12周,缩窄组小鼠出现失代偿性心力衰竭,左心室射血分数(EF%)、左心室压力上升和下降最大速率(dp/dtmax;dp/dtmin)显著降低(P<0.05),与8周缩窄组比较,12周缩窄组SBP、DBP、LVSP、LVEDP显著降低(P<0.05)。结论通过主动脉弓缩窄,可以建立稳定的小鼠压力超负荷诱导左室向心性肥厚致心衰的动物模型,类似人类心肌肥厚向心衰发展的病理过程,是用于临床研究的一种较理想动物模型。 展开更多
关键词 主动脉弓缩窄 压力负荷 左室肥厚 心力衰竭
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心肌梗死后心脏破裂的现代临床特征和挑战 被引量:3
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作者 卢群 马姗 +1 位作者 宋安齐 杜晓军 《中国医学前沿杂志(电子版)》 2019年第11期30-40,共11页
心脏破裂是急性心肌梗死后的致命并发症。在近30年间,心肌梗死患者院内死亡率显著下降,与此同时,心脏破裂的发生率也明显降低。然而,心脏破裂后患者的死亡率依然居高不下,是构成心肌梗死患者近期死亡的重要原因之一。因此,心脏破裂依然... 心脏破裂是急性心肌梗死后的致命并发症。在近30年间,心肌梗死患者院内死亡率显著下降,与此同时,心脏破裂的发生率也明显降低。然而,心脏破裂后患者的死亡率依然居高不下,是构成心肌梗死患者近期死亡的重要原因之一。因此,心脏破裂依然是现代心脏病学所面临的重要挑战之一。直接经皮冠状动脉介入治疗(primary percutaneous coronary inte rvention,pPCI)成为心肌梗死患者的常规治疗,新近的临床研究发现,高达50%的心脏破裂发生于心肌梗死后的48 h内,而且已有报道发现pPCI术后患者发生心脏破裂。自21世纪以来,对心脏破裂的危险预测和治疗手段并无明显进展。本文综述自pPCI常规应用以来心脏破裂的临床特征、发生率和预后的动态变化,讨论近15年中有关心脏破裂的病理生理机制、危险因素和治疗的临床前期研究,并提出亟待解答的重要问题。 展开更多
关键词 心脏破裂 心肌梗死 猝死 ST段抬高型心肌梗死 小鼠模型
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小鼠心肌缺血后适应模型的建立及其相关影响因素 被引量:3
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作者 张健发 马依彤 +3 位作者 杨毅宁 高晓明 刘芬 向阳 《中国比较医学杂志》 CAS 2007年第10期576-580,共5页
目的建立小鼠心肌缺血后适应模型,评价其对缺血再灌注损伤的保护作用以及相关的影响因素。方法120只成年雄性KM小鼠随机接受缺血后适应、缺血再灌注以及假手术3种不同的处理方式。后适应组采用开胸手术结扎左冠状动脉缺血45 min,建立急... 目的建立小鼠心肌缺血后适应模型,评价其对缺血再灌注损伤的保护作用以及相关的影响因素。方法120只成年雄性KM小鼠随机接受缺血后适应、缺血再灌注以及假手术3种不同的处理方式。后适应组采用开胸手术结扎左冠状动脉缺血45 min,建立急性心肌梗死模型,在完全再灌注早期给予反复短暂再通/闭塞的后适应。采用Evans blue和TTC染色的方法确定缺血心肌面积以及梗死心肌面积,并测定血清磷酸肌酸激酶(CK)、丙二醛(MDA)及超氧化物歧化酶(SOD)以及血流动力学指标。结果缺血后适应1组、后适应2组以及预适应+后适应组梗死心肌的重量百分比显著小于缺血-再灌注组,P<0.05;后适应2组以及预适应+后适应组与后适应1组比较差异无显著性;延迟后适应组梗死心肌的重量百分比与缺血-再灌注组比较差异无显著性,P>0.05。同时缺血后适应可以明显地降低缺血再灌注血清CK、MDA的浓度,提高SOD的水平以及改善血流动力学的恶化。结论在恢复冠脉血流的早期施行缺血后适应可以有效地减少小鼠再灌注心肌损伤。 展开更多
关键词 心肌再灌注损伤 缺血后适应 模型 动物 小鼠 TTC染色
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不同品系小鼠主动脉弓缩窄压力负荷模型的比较 被引量:4
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作者 李晓梅 马依彤 +5 位作者 杨毅宁 刘芬 黄莺 韩伟 高晓明 张健发 《实验动物与比较医学》 CAS 2008年第4期209-214,共6页
目的比较两种不同品系小鼠建立主动脉弓缩窄压力负荷模型后心脏形态及功能变化的差异。方法将雄性KM小鼠及C57BL/6小鼠各一组随机分为术前(n=10)、假手术组(n=10)及主动脉弓缩窄(TAC)组(n=30)。术前及术后8周应用高频心脏超声、血流动... 目的比较两种不同品系小鼠建立主动脉弓缩窄压力负荷模型后心脏形态及功能变化的差异。方法将雄性KM小鼠及C57BL/6小鼠各一组随机分为术前(n=10)、假手术组(n=10)及主动脉弓缩窄(TAC)组(n=30)。术前及术后8周应用高频心脏超声、血流动力学、心脏病理组织学方法进行检测,并进行死亡原因观察。结果(1)KM小鼠及C57BL/6小鼠缩窄组围手术成功率分别为80%及87%;8周存活率分别为67%及77%(。2)与各假手术组比较,缩窄术后8周KM及C57BL/6小鼠TAC组心脏超声指标左心室收缩期、舒张期前壁厚度(Awsth;Awdth)、左心室收缩期、舒张期后壁厚度(Pwsth;Pwdth)、左室重量指数(LVMI)、动脉收缩压(SBP)、动脉舒张压(DBP)、左心室收缩压(LVSP)、左心室舒张末压(LVEDP)、左心室压力上升和下降最大速率(dp/dtmax;dp/dtmin)及病理解剖指标心脏重量指数(H w/Bw)、左心室重量(LVw)、左心室重量指数(LV w/Bw)均显著增加(均P<0.05),显示左心室肥厚;KM缩窄组左心室收缩末期、舒张末期内径(LVESd;LVEDd)、左心室舒张末期外径(EXLVDd)较其假手术组显著增加(均P<0.05);与C57BL/6缩窄组比较,术后8周KM缩窄组LVESd、LVEDd、EXLVDd、LVw、肺脏重量指数(Lungw/Bw)显著增加(均P<0.05)。结论KM小鼠主动脉弓缩窄动物模型与C57BL/6小鼠实验结果相似,均产生左室肥厚,但KM小鼠较早出现离心性肥厚趋势。 展开更多
关键词 主动脉弓缩窄 左室肥厚 小鼠
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端粒酶与肿瘤 被引量:7
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作者 王伟 刘俊平 《世界华人消化杂志》 CAS 2002年第6期683-688,共6页
0 引言 目前端粒酶的调节及其在肿瘤发生发展中的作用已成为生命科学研究的一个热点.本文总结了近几年来有关端粒酶活性调节机制及其在肿瘤发生发展中作用的研究进展.
关键词 端粒酶 肿瘤 肿瘤生物学 调节机制 HTERT基因
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小鼠心脏破裂模型的建立及其影响因素 被引量:4
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作者 杨毅宁 马依彤 +3 位作者 李军 高晓明 刘芬 陈铀 《实验动物与比较医学》 CAS 2006年第2期67-71,127,共6页
目的探讨定量控制心肌梗死面积建立稳定小鼠心脏破裂模型的可行性,初步了解小鼠心脏破裂发生特点和规律。方法140只雄性C57BL小鼠随机分为冠状动脉高、中、低位结扎组各40只和假手术组20只,根据分组建立急性心肌梗死模型。术后观察心脏... 目的探讨定量控制心肌梗死面积建立稳定小鼠心脏破裂模型的可行性,初步了解小鼠心脏破裂发生特点和规律。方法140只雄性C57BL小鼠随机分为冠状动脉高、中、低位结扎组各40只和假手术组20只,根据分组建立急性心肌梗死模型。术后观察心脏破裂发生时间、部位和破裂率,7d后对存活小鼠行微导管术观察血流动力学变化及心脏病理组织学检查。结果(1)心脏破裂发生时间窗为心肌梗死后2~6d。中位结扎组心脏破裂率明显高于其余各组(P均<0.05);(2)高位结扎组心肌梗死面积比明显高于中位及低位结扎组(P均<0.05);(3)高位结扎组血流动力学指标较其余各组明显恶化(P均<0.05);(4)组织病理学观察中位结扎组心肌内出血和炎性细胞浸润评分较高位及低位结扎组明显增加(P均<0.05)。结论通过定位结扎冠状动脉形成中等面积心肌梗死,可以建立稳定心脏破裂模型,符合人类心脏破裂病理发展过程,是临床研究的一种动物模型。 展开更多
关键词 心肌梗死 小鼠 心脏破裂
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基于专利引文分析的时间线技术 被引量:10
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作者 孙涛涛 Steven A.Morris 黄亚明 《现代图书情报技术》 CSSCI 北大核心 2008年第6期51-55,共5页
在对专利引文可视化技术现状进行分析的基础上,将基于引文分析的时间线技术运用到专利文献的可视化分析。详细阐述该技术的理论依据、设计思想,并用美国专利数据库中的DVD激光头专利进行技术应用,证明该技术能揭示专利文献中的技术热点... 在对专利引文可视化技术现状进行分析的基础上,将基于引文分析的时间线技术运用到专利文献的可视化分析。详细阐述该技术的理论依据、设计思想,并用美国专利数据库中的DVD激光头专利进行技术应用,证明该技术能揭示专利文献中的技术热点及其发展演变,并挖掘关键技术。 展开更多
关键词 专利 引文分析 时间线 技术热点
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页岩气开采往复式压缩机管路系统气流脉动优化与结构振动安全评价 被引量:3
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作者 陈振 鞠浩文 +2 位作者 陈容 NAN LUAN 敬爽 《安全与环境学报》 CAS CSCD 北大核心 2023年第9期3060-3069,共10页
页岩气开采往复式压缩机管路系统长期受到气缸排出的高压脉动气体冲击载荷,引发受迫振动,严重影响开采效率与人员安全。针对脉动最为剧烈的二级排气管路,运用有限元仿真方法,分析气流脉动超标情况,掌握气流脉动变化规律,采用正交试验方... 页岩气开采往复式压缩机管路系统长期受到气缸排出的高压脉动气体冲击载荷,引发受迫振动,严重影响开采效率与人员安全。针对脉动最为剧烈的二级排气管路,运用有限元仿真方法,分析气流脉动超标情况,掌握气流脉动变化规律,采用正交试验方法,开展气流脉动优化研究,掌握了不同孔板孔径比对管路系统气流脉动的影响规律。结果表明,缓冲罐出入口管道孔板孔径比分别为0.4与0.45时,管路系统气流脉动抑制效果最优。据此,结合气流脉动周期性激励特点,建立了管路系统结构动态振动仿真模型,采用双向流固耦合方法,评价管路系统振动安全性能。优化后管路系统气流脉动幅值仅为API 618标准的18.50%,相比原模型减小了87.98%,且优化后管路系统振动安全,数值模拟与现场试验最大误差为振动位移误差12.14%,符合工程误差要求。 展开更多
关键词 安全工程 往复式压缩机 气流脉动 双向流固耦合 数值模拟 振动安全
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