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时间的构成与认知:杰尔的时间人类学理论内核述论 认领
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作者 木粲成 贾仲益 《民族学刊》 CSSCI 北大核心 2020年第1期83-93,141-142共13页
人类的时间观念何以异同是人类学时间研究的一个基本论题。对时间构成与时间认知的理解则左右着人类学家们对此论题的探究。20世纪90年代初,英国人类学家阿尔弗雷德·杰尔在继承与批判既往人类学家之时间论的基础上,综合多学科知识... 人类的时间观念何以异同是人类学时间研究的一个基本论题。对时间构成与时间认知的理解则左右着人类学家们对此论题的探究。20世纪90年代初,英国人类学家阿尔弗雷德·杰尔在继承与批判既往人类学家之时间论的基础上,综合多学科知识,析分出了作为事件之先后次序的客观时间("B系列"时间),作为过去、现在、未来意识的主观时间("A系列"时间),以及由主观时间模拟客观时间而生成的时间地图,并基于三者关系构建了一种普世的时间认知机制。杰尔认为,人类的时间认知作为人类基本认知机制运作的一种附带结果,在机制上具有普同性,而时间地图的内容则会随着人类经验与实践而变化,因此,人类学的时间研究应以时间认知机制之普同性为基础,注重探究时间地图之内容差异的社会文化根由。杰尔对时间的构成与认知的讨论是其时间人类学的理论内核,本文对其由来、内涵与缺陷进行了述论,以供后续研究参考。 展开更多
关键词 时间 认知 杰尔 时间人类学 “A系列”时间 “B系列”时间 时间地图
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An overview on GNSS carrier-phase time transfer research 认领
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作者 ZHANG Ming LU JinHu +2 位作者 BAI ZhengDong JIANG ZhiQi CHEN BoBo 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2020年第4期589-596,共8页
Global navigation satellite system(GNSS)carrier phase observations are two orders of higher accuracy than pseudo-range observations,and they are less affected by multipath besides.As a result,the time transfer accurac... Global navigation satellite system(GNSS)carrier phase observations are two orders of higher accuracy than pseudo-range observations,and they are less affected by multipath besides.As a result,the time transfer accuracy can reach 0.1 ns,and the frequency transfer stability can reach 1×10^-15 with carrier phase(CP)method,therefore CP method is considered the most accurate and promising time transfer technology.The focus of this paper is to present a comprehensive summary of CP method,with specific attention directed toward day-boundary clock jump,ambiguity resolution(AR),multi-system time transfer and real-time time transfer.Day-boundary clock jump is essentially caused by pseudo-range noise.Several approaches were proposed to solve the problem,such as continuously processing strategy,sliding batch and bidirectional filtering methods which were compared in this study.Additionally,researches on AR in CP method were introduced.Many scholars attempted to fix the single-difference ambiguities to improve the time transfer result,however,owing to the uncalibrated phase delay(UPD)was not considered,the current studies on AR in CP method were still immature.Moreover,because four GNSS systems could be used for time-transfer currently,which was helpful to increase the accuracy and reliability,the researches on multi-system time transfer were reviewed.What’s more,real-time time transfer attracted more attention nowadays,the preliminary research results were presented. 展开更多
关键词 carrier phase(CP) time transfer day-boundary clock jump ambiguity resolution(AR) multi-system time transfer real-time time transfer
Impact time control using biased proportional navigation for missiles with varying velocity 认领
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作者 Guoxin SUN Qiuqiu WEN +1 位作者 Zhiqiang XU Qunli XIA 《中国航空学报:英文版》 SCIE EI CAS CSCD 2020年第3期956-964,共9页
A feasible guidance scheme with impact time constraint is proposed for attacking a stationary target by missiles with time-varying velocity.The main idea is to replace the constant velocity with the future mean veloci... A feasible guidance scheme with impact time constraint is proposed for attacking a stationary target by missiles with time-varying velocity.The main idea is to replace the constant velocity with the future mean velocity;therefore, the existing time-to-go estimation algorithm of the proportional navigation guidance law can be improved to adapt to varying conditions.In order to obtain the prediction of the velocity profile, the velocity differential equation to the downrange is derived, which can be numerically integrated between the current downrange and the target position by the on-board computer.Then, a third-order polynomial is introduced to fit the velocity profile in order to calculate the future mean velocity.At the beginning of each guidance loop, the future mean velocity is predicted and the time-to-go information is updated, based on which a novel biased proportional navigation guidance law is established to achieve the impact time constraint.Finally,numerical simulation results verified the effectiveness of the time-to-go estimation algorithm and the proposed law. 展开更多
关键词 GUIDANCE Homing missiles Impact time Proportional navigation guidance Time-varying velocity
Enjoy the most beautiful scene now:a memetic algorithm to solve two-fold time-dependent arc orienteering problem 认领
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作者 Chao CHEN Liping GAO +1 位作者 Xuefeng XIE Zhu WANG 《中国计算机科学前沿:英文版》 SCIE EI CSCD 2020年第2期364-377,共14页
Traditional route planners commonly focus on finding the shortest path between two points in terms of travel distance or time over road networks.However,in real cases,especially in the era of smart cities where many k... Traditional route planners commonly focus on finding the shortest path between two points in terms of travel distance or time over road networks.However,in real cases,especially in the era of smart cities where many kinds of transportation-related data become easily available,recent years have witnessed an increasing demand of route planners that need to optimize for multiple criteria,e.g.,finding the route with the highest accumulated scenic score along(utility)while not exceeding the given travel time budget(cost).Such problem can be viewed as a variant of arc orienteering problem(AOP),which is well-known as an NP-hard problem.In this paper,targeting a more realistic AOP,we allow both scenic score(utility)and travel time(cost)values on each arc of the road network are time-dependent(2TD-AOP),and propose a memetic algorithm to solve it.To be more specific,within the given travel time budget,in the phase of initiation,for each population,we iteratively add suitable arcs with high scenic score and build a path from the origin to the destination via a complicate procedure consisting of search region narrowing,chromosome encoding and decoding.In the phase of the local search,each path is improved via chromosome selection,local-improvement-based mutation and crossover operations.Finally,we evaluate the proposed memetic algorithm in both synthetic and real-life datasets extensively,and the experimental results demonstrate that it outperforms the baselines. 展开更多
关键词 arc orienteering problem two-fold timedependent scenic score travel time memetic algorithm
基于时间的阴阳辨证体会 认领
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作者 刘野 植奇明 张参军(指导) 《中国中医药信息杂志》 CAS CSCD 2020年第3期116-117,共2页
时间在阴阳辨证中有重要作用,在疾病的诊断和治疗中被广泛应用,对于病情发生发展与时间有密切关系的疾病,可运用基于时间的阴阳辨证方法,指导分析病性、确定治疗方法的方向,从而提高临床疗效。
关键词 阴阳辨证 时间
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基于Cartoon time板块的小学中高年级英语趣味写作实践 认领
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作者 张洁 《基础外语教育》 2020年第1期90-96,111,112共9页
本文结合译林版小学英语教材中Cartoon time板块的趣味故事,在小学中高年级开展替换、改写、续编等形式的趣味英语写作活动,旨在激发学生的想象力,培养学生的英语学习兴趣,提高学生的英语写作能力。
关键词 CARTOON TIME 小学英语 趣味写作
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How does anodization time affect morphological and photocatalytic properties of iron oxide nanostructures? 认领
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作者 Bianca Lucas-Granados Rita Sánchez-Tovar +2 位作者 Ramón MFernández-Domene JoséMaría Estívalis-Martínez JoséGarcía-Antón 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第3期159-169,共11页
Iron oxide nanostructures are promising materials to be used as photocatalysts in different photoelectrochemical applications. There are different techniques in order to synthesize these nanostructures, but one of the... Iron oxide nanostructures are promising materials to be used as photocatalysts in different photoelectrochemical applications. There are different techniques in order to synthesize these nanostructures, but one of the most inexpensive and simple method is electrochemical anodization. This method can lead to different nanostructures by controlling its parameters. Anodization time is one of the most critical parameters since it considerably affects the properties of the obtained nanostructures. In this work, different anodization times(5, 10, 15, 30 and 60 min) were studied. The resulting nanotubes were characterized by field emission scanning electron microscopy, Raman laser confocal microscopy, water splitting measurements, Mott-Schottky analysis and electrochemical impedance spectroscopy, in order to test their viability for being used as photocatalysts in photoelectrochemical applications. Results showed that the best photocurrent density values in water splitting tests(0.263 m A m-2) were achieved for the sample anodized for 10 min under hydrodynamic conditions. 展开更多
关键词 Iron oxide Metallic NANOSTRUCTURES PHOTOELECTROCHEMISTRY Anodization TIME
从海德格尔的“存在与时间”看老建筑的保护与更新 认领
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作者 解飞 《住区》 2020年第1期177-181,共5页
文章首先介绍古希腊以来时间观念在哲学和宗教中的演逬过程,接下来通过解释海德格尔哲学中的五个重要概念,逬一步解释海德格尔的时间观,在此基础上重新审视老建筑的保护与更新:分别从“时间”和“存在”两个核心视角逬行探索,最后得出结... 文章首先介绍古希腊以来时间观念在哲学和宗教中的演逬过程,接下来通过解释海德格尔哲学中的五个重要概念,逬一步解释海德格尔的时间观,在此基础上重新审视老建筑的保护与更新:分别从“时间”和“存在”两个核心视角逬行探索,最后得出结论,并对老建筑的保护与更新策略准则逬行展望。 展开更多
关键词 住区 海德格尔 时间 老建筑 保护 更新
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Time-dependent Ginzburg–Landau equations for multi-gap superconductors 认领
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作者 李敏斯 古家虹 +3 位作者 杜龙 钟红伟 周丽娟 陈庆华 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第3期385-388,共4页
We numerically solve the time-dependent Ginzburg–Landau equations for two-gap superconductors using the finite-element technique. The real-time simulation shows that at low magnetic field, the vortices in small-size ... We numerically solve the time-dependent Ginzburg–Landau equations for two-gap superconductors using the finite-element technique. The real-time simulation shows that at low magnetic field, the vortices in small-size samples tend to form clusters or other disorder structures. When the sample size is large, stripes appear in the pattern. These results are in good agreement with the previous experimental observations of the intriguing anomalous vortex pattern, providing a reliable theoretical basis for the future applications of multi-gap superconductors. 展开更多
关键词 vortex multi-gap SUPERCONDUCTIVITY time dependent finite element technique
儿童婴幼儿期视屏接触时间与孤独症样行为的关联 认领
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作者 吴剑波 尹晓娜 +3 位作者 吴传安 温国明 杨伟康 静进 《中国学校卫生》 CAS 北大核心 2020年第1期21-24,共4页
目的探讨婴幼儿期视屏接触时间与孤独症样行为的关联,为探索孤独症水平行为的影响机制提供线索。方法采用回顾性研究,调查深圳市龙华区22586名幼儿园儿童的主要养育者,用自编问卷收集一般人口学变量、视屏接触时间,采用儿童孤独症行为量... 目的探讨婴幼儿期视屏接触时间与孤独症样行为的关联,为探索孤独症水平行为的影响机制提供线索。方法采用回顾性研究,调查深圳市龙华区22586名幼儿园儿童的主要养育者,用自编问卷收集一般人口学变量、视屏接触时间,采用儿童孤独症行为量表(Autism Behavior Checklist,ABC)评估孤独症样行为,分析婴幼儿过早接触视屏对孤独症样行为的影响。结果婴幼儿期电视和新一代电子产品的视屏接触时间均随年龄增长而增长。<1,1~<2,2~3岁电视视屏0 h/d的比例分别为60.1%,35.0%,20.2%,新一代电子产品视屏0 h/d的比例分别为74.0%,52.6%,26.8%。儿童ABC量表阳性率为5.3%,男性(6.0%)比女性(4.4%)高[OR值(95%CI)为1.37(1.23~1.54)]。各年龄段电视和新一代电子产品的视屏接触时间均与孤独症样行为有相关性(P<0.05)。1岁内中高视屏组,2~3岁保持中高视屏接触时间、逐渐增加视屏接触时间与2~3岁无视屏组相比,孤独症样行为的风险更高且视屏接触时间越长风险越大(电视视屏组OR值分别为2.14,2.77;亲子一代电子产品视屏组OR值分别为2.48,2.81,P值均<0.05)。0~3岁每日观看视屏≥1,<1 h/d组与无视屏组相比,电视视屏的OR值分别为2.45,2.01,新一代电子产品视屏的OR值分别为2.33,2.01(P值均<0.05)。0~3岁单次视屏接触时间越长孤独症样行为的风险越大,≥1 h/次、0.5~<1 h/次、15~30 min/次与<15 min/次相比,OR值分别为2.50,1.79,1.47(P值均<0.05)。结论婴幼儿期过早接触视屏、每日观看视屏总时间过多、单次视屏接触时间过长均可能增加孤独症样行为。2岁内的婴幼儿不宜每天视屏,2~3岁应控制视屏总时间<0.5 h/d且单次视屏<15 min。 展开更多
关键词 计算机终端 时间 孤独性障碍 行为 回归分析 儿童
老年髋部骨折病人运动疗法研究进展 认领
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作者 屈婧 席明霞 +1 位作者 肖美慧 郑露晴 《护理研究》 北大核心 2020年第4期673-676,共4页
从运动疗法的概念及其必要性、开展现状、实施方法及影响因素等方面对老年髋部骨折病人运动疗法研究进展进行综述,旨在为老年髋部骨折病人运动疗法的实施提供参考。
关键词 髋部骨折 运动疗法 影响因素 时间 自我效能 动机 健康因素 综述
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Lifestyle and Time Use:The Impact of Retirement on Health 认领
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作者 Su Chunhong Li Song 《当代社会科学(英文)》 2020年第1期140-155,共16页
Based on the data from the China Health and Retirement Longitudinal Study(CHARLS)in 2011 and 2013,this paper studied the impact of retirement on male and female workers’health and its impact mechanism under the manda... Based on the data from the China Health and Retirement Longitudinal Study(CHARLS)in 2011 and 2013,this paper studied the impact of retirement on male and female workers’health and its impact mechanism under the mandatory retirement age system in China by using Fuzzy Regression Discontinuity Design(FRDD).The results indicated that retirement increased the probability of men assessing themselves as"healthy"by 25 percentage points and lowered the probability of suffering from chronic diseases for women by 26 percentage points.In terms of mechanism analysis,it was found that the remarkable increase in social interactions after retirement was the main reason for the improvement of health for male retirees,but not the reason for the lower probability of having chronic diseases for female retirees.The findings serve as important references for formulating policies regarding postponing retirement age and flexible retirement. 展开更多
关键词 RETIREMENT HEALTH mechanism LIFESTYLE and time USE Fuzzy Regression DISCONTINUITY
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Preparation of Spherical FePO4 by Chemical Co-precipitation Combined with Spray-Drying 认领
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作者 Leping Dang Hongtao Zhang +1 位作者 Xin Xu Xiaojun Lang 《天津大学学报:英文版》 EI CAS 2020年第1期57-66,共10页
Well-shaped spherical agglomerates of FePO4 particles were prepared by a novel method:chemical co-precipitation combined with spray-drying.Tap density analysis,Brunauer-Emmett-Teller analysis,characterizations of X-ra... Well-shaped spherical agglomerates of FePO4 particles were prepared by a novel method:chemical co-precipitation combined with spray-drying.Tap density analysis,Brunauer-Emmett-Teller analysis,characterizations of X-ray diffraction,scanning electron microscopy,and transmission electron microscopy confirmed that the micron-sized spherical agglomerates with high specific surface area and high tap density were composed of the uniform nano-sized particles.The effects of pH and reaction time on the morphology of the FePO4 particles were investigated by experimental and theoretical analyses.The analyses revealed that amorphous FePO4 was responsible for forming a well-shaped spherical agglomerate,and the ideal spherical particles were obtained at pH 3.The reaction time also played a significant role in controlling the size and surface morphology of the FePO4 particles,and smooth spherical FePO4 particles were obtained at a reaction time of 6 h.By this novel method,poly-porous spherical iron phosphate particles were prepared,which can be used with high efficiency in some special fields,especially as a precursor for synthesizing LiFePO4 and catalysts. 展开更多
关键词 FEPO4 SPHERICAL AGGLOMERATE SPRAY-DRYING pH REACTION time
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莎士比亚十四行诗中的“时间”隐喻与语篇连贯 认领
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作者 田薇 《宜春学院学报》 2020年第1期91-94,共4页
诗歌用词凝练,缺乏显性的语篇连贯手段。通过解析莎士比亚十四行诗中“时间的流逝”和“时间的影响”两个子隐喻和“+TIME IS AN ENTITY+(时间是个实体)”实体隐喻,探讨诗歌中的认知连贯机制。两个子隐喻的延伸和推进,并统一在+TIME IS ... 诗歌用词凝练,缺乏显性的语篇连贯手段。通过解析莎士比亚十四行诗中“时间的流逝”和“时间的影响”两个子隐喻和“+TIME IS AN ENTITY+(时间是个实体)”实体隐喻,探讨诗歌中的认知连贯机制。两个子隐喻的延伸和推进,并统一在+TIME IS AN ENTITY+(时间是个实体)这个大的隐喻框架下,构成一个隐喻系统和网络,使整部诗集主题一致、鲜明,内容连贯、紧凑,同时给读者无尽的遐想空间。 展开更多
关键词 隐喻 十四行诗 语篇连贯 “时间”
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Blow-up Time Estimates of Parabolic Equations with General Coupled Nonlinearities 认领
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作者 HU Cai-hua LI Feng-jie WANG Qian-xi 《数学季刊:英文版》 2020年第1期77-92,共16页
This paper deals with some parabolic equations,where the reaction and the boundary flux are taken of some general forms.We study the explicit blow-up time estimates according to the different coupled relationship,incl... This paper deals with some parabolic equations,where the reaction and the boundary flux are taken of some general forms.We study the explicit blow-up time estimates according to the different coupled relationship,including the lower and upper bounds of blow­up time for every dimension of space domains.As examples,the results could be used to so many completely coupled models. 展开更多
关键词 parabolic equations general coupled nonlinearity boundary flux blow-up time estimates
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Multiple Lagrange stability and Lyapunov asymptotical stability of delayed fractional-order Cohen-Grossberg neural networks 认领
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作者 黄玉娇 袁孝焰 +2 位作者 杨旭华 龙海霞 肖杰 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第2期196-205,共10页
This paper addresses the coexistence and local stability of multiple equilibrium points for fractional-order Cohen-Grossberg neural networks(FOCGNNs)with time delays.Based on Brouwer's fixed point theorem,sufficie... This paper addresses the coexistence and local stability of multiple equilibrium points for fractional-order Cohen-Grossberg neural networks(FOCGNNs)with time delays.Based on Brouwer's fixed point theorem,sufficient conditions are established to ensure the existence of Πi=1^n(2Ki+1)equilibrium points for FOCGNNs.Through the use of Hardy inequality,fractional Halanay inequality,and Lyapunov theory,some criteria are established to ensure the local Lagrange stability and the local Lyapunov asymptotical stability of Πi=1^n(Ki+1)equilibrium points for FOCGNNs.The obtained results encompass those of integer-order Hopfield neural networks with or without delay as special cases.The activation functions are nonlinear and nonmonotonic.There could be many corner points in this general class of activation functions.The structure of activation functions makes FOCGNNs could have a lot of stable equilibrium points.Coexistence of multiple stable equilibrium points is necessary when neural networks come to pattern recognition and associative memories.Finally,two numerical examples are provided to illustrate the effectiveness of the obtained results. 展开更多
关键词 FRACTIONAL-ORDER COHEN-GROSSBERG neural networks MULTIPLE Lagrange STABILITY MULTIPLE LYAPUNOV asymptotical STABILITY time DELAYS
标准流量积算仪的研究与实现 认领
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作者 臧振胜 《仪器仪表用户》 2020年第5期22-24,共3页
介绍了标准流量积算仪的基本功能,从硬件构成、仪表接口和控制逻辑几个方面,详细阐述了标准流量积算仪在计量检定和校准装置中的应用。在音速喷嘴气流量标准装置、钟罩式气体流量标准装置、静动态质量法水流量标准装置、静动态容积法水... 介绍了标准流量积算仪的基本功能,从硬件构成、仪表接口和控制逻辑几个方面,详细阐述了标准流量积算仪在计量检定和校准装置中的应用。在音速喷嘴气流量标准装置、钟罩式气体流量标准装置、静动态质量法水流量标准装置、静动态容积法水流量标准装置和标准体积管流量标准装置中,可以准确地采集标准计量时间、标准表和被检表的脉冲频率、脉冲累积量以及被检表的电流信号值。通过面板控制,DI端子触发和串口命令3种方式实现仪表的启停控制,以实现智能化采集,并根据数值大小调整小数点的显示位数。经测试比较,标准流量积算仪可以稳定高效地作为标准装置的计量仪表,达到了预期的设计效果。 展开更多
关键词 积算仪 脉冲 电流 晶振 时间 定量 热电阻
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关于时空弯曲的疑问与验证新方法 认领
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作者 王旭东 《科教文汇》 2020年第1期65-67,共3页
对爱因斯坦关于“时间”“空间”论证的理论基础的正确性、论据(数据)的有效性、论证过程的规范性、在“环球航行原子钟实验”中选择定量与定性分析的依据问题、空间弯曲示意图的真伪性、日全食星星偏移照片的有效性等问题提出了相应的... 对爱因斯坦关于“时间”“空间”论证的理论基础的正确性、论据(数据)的有效性、论证过程的规范性、在“环球航行原子钟实验”中选择定量与定性分析的依据问题、空间弯曲示意图的真伪性、日全食星星偏移照片的有效性等问题提出了相应的疑问,并提出了“不同纬度时钟实验”和“等效日全食实验”,作为验证爱因斯坦“时、空”观点的验证新方法。 展开更多
关键词 狭义相对论 时间 动钟变慢 空间 空间弯曲
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Ethanol extract from Gynostemma pentaphyllum ameliorates dopaminergic neuronal cell death in transgenic mice expressing mutant A53T human alpha-synuclein 认领
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作者 Hyun Jin Park Ting Ting Zhao +4 位作者 Seung Hwan Kim Chong Kil Lee Bang Yeon Hwang Kyung Eun Lee Myung Koo Lee 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第2期361-368,共8页
Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal... Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal models of Parkinson’s disease(PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-and 6-hydroxydopamine. PD patients exhibit multiple symptoms, so PD-related research should combine neurotoxin models with genetic models. In the present study, we investigated the ameliorative effects of GP-EX, including gypenosides, on the cell death of dopaminergic neurons in the midbrain of A53 T α-synuclein transgenic mouse models of PD(A53 T). Both GP-EX and gypenosides at 50 mg/kg per day were orally administered to the A53 T mice for 20 weeks.α-Synuclein-immunopositive cells and α-synuclein phosphorylation were increased in the midbrain of A53 T mice, which was reduced following treatment with GP-EX. Treatment with GP-EX modulated the reduced phosphorylation of tyrosine hydroxylase, extracellular signal-regulated kinase(ERK1/2), Bcl-2-associated death promoter(Bad) at Ser112, and c-Jun N-terminal kinase(JNK1/2) due to α-synuclein overexpression. In the A53 T group, GP-EX treatment prolonged the latency of the step-through passive avoidance test and shortened the transfer latency of the elevated plus maze test. Gypenosides treatment exhibited the effects and efficacy similar to those of GP-EX. Taken together, GP-EX, including gypenosides, has ameliorative effects on dopaminergic neuronal cell death due to the overexpression of α-synuclein by modulating ERK1/2, Bad at Ser112, and JNK1/2 signaling in the midbrain of A53 T mouse model of PD. Further studies are needed to investigate GP-EX as a treatment for neurodegenerative synucleinopathies, including PD. This study was approved by the Animal Ethics Committee of Chungbuk National University(approval No. CBNUA-956-16-01) on September 21, 2016. 展开更多
关键词 A53T α-synuclein genetic mice ERK1/2 GYNOSTEMMA pentaphyllum GYPENOSIDES Parkinson’s disease retention transfer LATENCY time
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高温快速发酵对鸡粪重金属形态分布及有机质含量影响 认领
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作者 栾润宇 李佳佳 +2 位作者 纪艺凝 闫翠侠 孙约兵 《中国土壤与肥料》 CAS CSCD 北大核心 2020年第2期232-240,共9页
以鸡粪、玉米秸秆为主要原料,通过添加酵素进行好氧堆肥发酵试验,研究了不同温度和时间下堆肥pH值、EC值、重金属含量与形态、腐殖质含量变化以及红外光谱特征。结果表明,与堆肥前相比,pH值随温度升高和时间的延长而增大,最大可增加0.5... 以鸡粪、玉米秸秆为主要原料,通过添加酵素进行好氧堆肥发酵试验,研究了不同温度和时间下堆肥pH值、EC值、重金属含量与形态、腐殖质含量变化以及红外光谱特征。结果表明,与堆肥前相比,pH值随温度升高和时间的延长而增大,最大可增加0.53个单位,而EC值随堆肥时间延长表现为先增加后降低的趋势,在85℃处理下最低。由于浓缩效应,重金属含量均不同程度增加,Cu、Zn、Cr、Cd和As含量较堆肥前相比最大增幅分别达到35.6%、11.5%、35.0%、35.3%和23.8%。然而,重金属可交换态分配率则有所降低,残渣态比例相应增加,与堆肥前相比,鸡粪有机肥中Cu、Zn、Cr、Cd和As钝化率分别为24.8%、26.0%、27.6%、26.9%和13.9%。高温处理下,胡敏酸和富里酸含量较低,胡敏酸/富里酸(HA/FA)比值随着堆肥时间和温度增加而增大,且随着堆肥进程脂肪族、芳香族、羧酸类分子以及多糖类物质均有所减少。结果显示高温下(85℃)不仅加快堆肥发酵进程,而且可以有效钝化重金属,可达到无害化效果。 展开更多
关键词 鸡粪 发酵 重金属 温度 时间
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