The advancement in extraterrestrial exploration has highlighted the crucial need for studying how the human cardiovascular system adapts to space conditions.Human development occurs under the influence of gravity,shie...The advancement in extraterrestrial exploration has highlighted the crucial need for studying how the human cardiovascular system adapts to space conditions.Human development occurs under the influence of gravity,shielded from space radiation by Earth’s magnetic field,and within an environment characterized by 24-hour day-night cycles resulting from Earth’s rotation,thus deviating from these conditions necessitates adaptive responses for survival.With upcoming manned lunar and Martian missions approaching rapidly,it is essential to understand the impact of various stressors induced by outer-space environments on cardiovascular health.This comprehensive review integrates insights from both actual space missions and simulated experiments on Earth,to analyze how microgravity,space radiation,and disrupted circadian affect cardiovascular well-being.Prolonged exposure to microgravity induces myocardial atrophy and endothelial dysfunction,which may be exacerbated by space radiation.Mitochondrial dysfunction and oxidative stress emerge as key underlying mechanisms along with disturbances in ion channel perturbations,cytoskeletal damage,and myofibril changes.Disruptions in circadian rhythms caused by factors such as microgravity,light exposure,and irregular work schedules,could further exacerbate cardiovascular issues.However,current research tends to predominantly focus on disruptions in the core clock gene,overlooking the multifactorial nature of circadian rhythm disturbances in space.Future space missions should prioritize targeted prevention strategies and early detection methods for identifying cardiovascular risks,to preserve astronaut health and ensure mission success.展开更多
The steroidal saponins are one of the saponin types that exist in an unbound state and have various pharmacological activities,such as anticancer,anti-inflammatory,antiviral,antibacterial and nerves-calming properties...The steroidal saponins are one of the saponin types that exist in an unbound state and have various pharmacological activities,such as anticancer,anti-inflammatory,antiviral,antibacterial and nerves-calming properties.Cancer is a growing health problem worldwide.Significant progress has been made to understand the antitumor effects of steroidal saponins in recent years.According to reported findings,steroidal saponins exert various antitumor activities,such as inhibiting proliferation,inducing apoptosis and autophagy,and regulating the tumor microenvironment,through multiple related signaling pathways.This article focuses on the advances in domestic and foreign studies on the antitumor activity and mechanism of actions of steroidal saponins in the last five years to provide a scientific basis and research ideas for further development and clinical application of steroidal saponins.展开更多
Two-dimensional(2D)transition metal carbides known as MXenes belong to a new branch of 2D material family,and their fundamental properties vary with their compositions and surface functionalizations.In this study,the ...Two-dimensional(2D)transition metal carbides known as MXenes belong to a new branch of 2D material family,and their fundamental properties vary with their compositions and surface functionalizations.In this study,the structural and ideal mechanical properties of M2C-type MXenes and their functionalized M2CT2 MXenes(M=Ti,Zr,Hf;T=O,F,OH)were systematically examined via first-principles methods.The stress–strain curves of the MXenes under homogenous biaxial and uniaxial tension are identified,and the fundamental quantities(e.g.,Young’s modulus,in-plane stiffness,and Poisson’s ratio)are addressed.With significantly higher strength and extended critical strains,the M2CO2 MXenes exhibit optimal flexibility when compared with that of M2C,M2CF2,and M2C(OH)2.Additionally,Hf2CT2 exhibits optimal tensile performance under uniaxial or biaxial tension when compared to that of Ti2CT2 and Zr2CT2.The Young’s modulus,in-plane stiffness,and Poisson’s ratio of MXenes with different surface functionalization increase in a sequence corresponding to OH\F\O.Furthermore,the effects of vacancy on the mechanical properties of MXenes are further explored and indicate that vacancy can significantly weaken the tensile properties of MXenes that are considered.Moreover,vacancy also results in a certain anisotropy of stress along armchair and zigzag directions even under the biaxial tension condition.展开更多
大熊猫曾广泛分布于中国南方地区,但很少有全新世以来的相关材料报道。尤其进入历史时期,仅有文献记录却未见实物材料。贵州双河洞截至目前共发现大熊猫化石个体50余个,它们主要的时代贯穿整个晚更新世。其中2019年在贵州双河洞区域的...大熊猫曾广泛分布于中国南方地区,但很少有全新世以来的相关材料报道。尤其进入历史时期,仅有文献记录却未见实物材料。贵州双河洞截至目前共发现大熊猫化石个体50余个,它们主要的时代贯穿整个晚更新世。其中2019年在贵州双河洞区域的黄家大坪大消坑竖井下方发现一具大熊猫头骨遗骸,并伴有人类及狗骨骼遗存。该个体的下裂齿m1的长度为32.60 mm,完全落入现生大熊猫的变异范围内。将大熊猫骨骼送至两个不同实验室分别测得AMS-14C年龄为940±20 a B.P.和860±30 a B.P.,表明该个体生活在距今约800~900年前,而人类及狗则主要为近100年内死亡的。该大熊猫个体是目前大熊猫在中国长江中下游及其以南地区最晚的实物记录。大熊猫在区域上灭绝可能发生在数百年前,与人类活动扩张息息相关。展开更多
建筑信息模型(Building Information Modeling)技术可以优化绿色建筑项目进度管理与控制中的效能及路径。通过理论分析与实践验证,发现BIM技术依托三维可视化模型与协同平台,可提升计划科学性、资源管理精度和进度监控效率,降低人工管...建筑信息模型(Building Information Modeling)技术可以优化绿色建筑项目进度管理与控制中的效能及路径。通过理论分析与实践验证,发现BIM技术依托三维可视化模型与协同平台,可提升计划科学性、资源管理精度和进度监控效率,降低人工管理数据偏差率。研究揭示,其应用受限于高开发成本、标准化缺失及跨专业协作壁垒等问题。提出建立BIM标准体系等策略,为建筑行业数字化转型提供理论支撑,推动绿色建筑全生命周期管理效能提升。展开更多
基金supported by the National Natural Science Fund for Distinguished Young Scholars of China(82125004).
文摘The advancement in extraterrestrial exploration has highlighted the crucial need for studying how the human cardiovascular system adapts to space conditions.Human development occurs under the influence of gravity,shielded from space radiation by Earth’s magnetic field,and within an environment characterized by 24-hour day-night cycles resulting from Earth’s rotation,thus deviating from these conditions necessitates adaptive responses for survival.With upcoming manned lunar and Martian missions approaching rapidly,it is essential to understand the impact of various stressors induced by outer-space environments on cardiovascular health.This comprehensive review integrates insights from both actual space missions and simulated experiments on Earth,to analyze how microgravity,space radiation,and disrupted circadian affect cardiovascular well-being.Prolonged exposure to microgravity induces myocardial atrophy and endothelial dysfunction,which may be exacerbated by space radiation.Mitochondrial dysfunction and oxidative stress emerge as key underlying mechanisms along with disturbances in ion channel perturbations,cytoskeletal damage,and myofibril changes.Disruptions in circadian rhythms caused by factors such as microgravity,light exposure,and irregular work schedules,could further exacerbate cardiovascular issues.However,current research tends to predominantly focus on disruptions in the core clock gene,overlooking the multifactorial nature of circadian rhythm disturbances in space.Future space missions should prioritize targeted prevention strategies and early detection methods for identifying cardiovascular risks,to preserve astronaut health and ensure mission success.
基金supported by the National Natural Science Foundation of China(No.81503295)2011 Program for Excellent Scientific and Technological Innovation Team of Jiangsu Higher Education+1 种基金Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsJiangsu Province 2011 Plan for Collaborative Innovation
文摘The steroidal saponins are one of the saponin types that exist in an unbound state and have various pharmacological activities,such as anticancer,anti-inflammatory,antiviral,antibacterial and nerves-calming properties.Cancer is a growing health problem worldwide.Significant progress has been made to understand the antitumor effects of steroidal saponins in recent years.According to reported findings,steroidal saponins exert various antitumor activities,such as inhibiting proliferation,inducing apoptosis and autophagy,and regulating the tumor microenvironment,through multiple related signaling pathways.This article focuses on the advances in domestic and foreign studies on the antitumor activity and mechanism of actions of steroidal saponins in the last five years to provide a scientific basis and research ideas for further development and clinical application of steroidal saponins.
基金supported by the National Natural Science Foundation of China(Nos.11605273 and 11847064)the Shanghai Municipal Science and Technology Commission(No.16ZR1443100)
文摘Two-dimensional(2D)transition metal carbides known as MXenes belong to a new branch of 2D material family,and their fundamental properties vary with their compositions and surface functionalizations.In this study,the structural and ideal mechanical properties of M2C-type MXenes and their functionalized M2CT2 MXenes(M=Ti,Zr,Hf;T=O,F,OH)were systematically examined via first-principles methods.The stress–strain curves of the MXenes under homogenous biaxial and uniaxial tension are identified,and the fundamental quantities(e.g.,Young’s modulus,in-plane stiffness,and Poisson’s ratio)are addressed.With significantly higher strength and extended critical strains,the M2CO2 MXenes exhibit optimal flexibility when compared with that of M2C,M2CF2,and M2C(OH)2.Additionally,Hf2CT2 exhibits optimal tensile performance under uniaxial or biaxial tension when compared to that of Ti2CT2 and Zr2CT2.The Young’s modulus,in-plane stiffness,and Poisson’s ratio of MXenes with different surface functionalization increase in a sequence corresponding to OH\F\O.Furthermore,the effects of vacancy on the mechanical properties of MXenes are further explored and indicate that vacancy can significantly weaken the tensile properties of MXenes that are considered.Moreover,vacancy also results in a certain anisotropy of stress along armchair and zigzag directions even under the biaxial tension condition.
文摘大熊猫曾广泛分布于中国南方地区,但很少有全新世以来的相关材料报道。尤其进入历史时期,仅有文献记录却未见实物材料。贵州双河洞截至目前共发现大熊猫化石个体50余个,它们主要的时代贯穿整个晚更新世。其中2019年在贵州双河洞区域的黄家大坪大消坑竖井下方发现一具大熊猫头骨遗骸,并伴有人类及狗骨骼遗存。该个体的下裂齿m1的长度为32.60 mm,完全落入现生大熊猫的变异范围内。将大熊猫骨骼送至两个不同实验室分别测得AMS-14C年龄为940±20 a B.P.和860±30 a B.P.,表明该个体生活在距今约800~900年前,而人类及狗则主要为近100年内死亡的。该大熊猫个体是目前大熊猫在中国长江中下游及其以南地区最晚的实物记录。大熊猫在区域上灭绝可能发生在数百年前,与人类活动扩张息息相关。
文摘建筑信息模型(Building Information Modeling)技术可以优化绿色建筑项目进度管理与控制中的效能及路径。通过理论分析与实践验证,发现BIM技术依托三维可视化模型与协同平台,可提升计划科学性、资源管理精度和进度监控效率,降低人工管理数据偏差率。研究揭示,其应用受限于高开发成本、标准化缺失及跨专业协作壁垒等问题。提出建立BIM标准体系等策略,为建筑行业数字化转型提供理论支撑,推动绿色建筑全生命周期管理效能提升。
