检索结果-南通市图书馆

The formation of Ca^(2+) gradients at the cleavage furrows during cytokinesis of Zebrafish embryos

Frontiers in Biology 2010年第4期5卷 369-377页

作者： Yun-Bo GUO Ya WEN Wen-Xue GAO Jing-Chao LI Peng ZHOU Zai-ling bai Bo ZHANG Shi-Qiang WANG State Key Laboratory of Biomembrane and Membrane Biotechnology and Center of Developmental Biology and GeneticsCollege of Life SciencesPeking UniversityBeijing 100871China

In dividing embryos,a localized elevation in intracellular Ca^(2+)([Ca^(2+)]i)at the cleavage furrow has been shown to be essential for ***,the underlying mechanisms for generating and maintaining these[Ca^(2+)]_(i) gradients throughout cytokinesis are not fully *** the present study,we analyzed the role of inositol 1,4,5-trisphosphate receptors(IP3Rs)and endoplasmic reticulum(ER)distribution in determining the intracellular Ca^(2+) gradients in early zebrafish *** of the injected Ca^(2+) indicator,Indo-1,showed that during the first cell division a standing Ca^(2+) gradient was formed~35 min after fertilization,with the[Ca^(2+)]_(i) spatially decaying from 500–600 nmol/L at the cleavage furrow to 100–200 nmol/L around the *** the IP3R immunohistochemical fluorescence was relatively concentrated in the peri-furrow region,ER labeling was relatively enriched in both peri-furrow and peri-nuclear *** simulation suggested that a divergence in the spatial distribution of IP3R and the locations of Ca^(2+) uptake within the ER was essential for the formation of a standing Ca^(2+) gradient,and the Ca^(2+) gradient could only be well-established under an optimal stoichiometry of Ca^(2+) uptake and ***,while inhibition of IP3R Ca^(2+) release blocked the generation of the Ca^(2+)gradient at a lower[Ca^(2+)]_(i) level,both Ca^(2+) release stimulation by inositol 1,4,5-trisphosphate(IP3)injection and ER Ca^(2+) pump inhibition by cyclopiazonic acid also eliminated the Ca^(2+) gradients at higher[Ca^(2+)]_(i) *** results suggest a dynamic relationship between ER-mediated Ca^(2+) release and uptake that underlies the maintenance of the perifurrow Ca^(2+) gradient and is essential for cytokinesis of zebrafish embryos.

关键词： Ca^(2+)gradients cytokinesis zebrafish

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

NEW CLOSED-LOOP DRIVING CIRCUIT OF SILICON MICROMACHINED VIBRATORY GYROSCOPE

引用

Transactions of Nanjing University of Aeronautics and Astronautics 2005年第2期22卷 150-154页

作者： YANGBo SUYah ZHOUbai-ling DepartmentofInstrumentScienceandEngineering SoutheastUniversityNanjing210096P.R.China

A new closed-loop driving scheme for the silicon micromachined vibratory gyroscope (SMVG) is proposed. The push-pull driving is adopted and in-phase AC and reverse-phase DC voltages are applied in the driving electrodes placed in both sides of the active combs, respectively. Driving performance analyses show that the frequency spectrum between driving moments and noise signals is separated. Therefore, the model of the closed-loop control is set up with the phase lock loop (PLL). The requirements for phases and gains of the sinusoidal selfdrive-oscillation are met by PLL, thus the closed-loop circuit reaches the self-drive-oscillation. Phase conditions of the sinusoidal self-drive-oscillation and the characteristic of phase discrimination of the PLL are used to eliminate the coupling between driving and sense signals, and noise signals. Finally, experimental results show that the variations of both the driving frequency and the amplitude are all under 0.02%. The precision and the reliability of the gyroscope are greatly improved.

关键词：相锁闭环硅微机械振动陀螺仪自驱动光谱频率

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An investigation on the dosimetric impact of hip prosthesis in radiotherapy

引用

Nuclear Science and Techniques 2016年第1期27卷 29-36页

作者： Wen-Cheng Shao Yan-ling bai Wen-Bo Zhao Pu-Nan Sun Feng-Li Liu Department of Radiation Physics Harbin Medical University Cancer Hospital Beijing Xiao Qing Environmental Engineering Co. LtdHarbin office School of physical science and technology Heilongjiang University

The objectives of this study are to evaluate the dosimetric impact of hip prosthesis using ELEKTA linac X-rays and compare the dose perturbations of metallic and nonmetallic hip prostheses. The local dose distributions of typical hip prostheses were calculated for 4, 8, and 15 MV beams by Geant4. Three prosthesis materials were selected in calculation to reveal the relation between material type and local dose perturbations of prostheses. Furthermore,the effect of nominal energy on prosthesis perturbation was also discussed and analyzed. Taking the calculated dose to the hip joint as reference, considerable differences were observed between prostheses and hip joints. In the prosthesis shadow region, the relative dose decreasing was up to 36, 21, and 16 % for the Co–Cr–Mo alloy, titanium alloy, and ceramic prostheses, respectively. In backscattering region, the relative dose increasing was about1–7 %. Overall, the results show that the dose perturbation effect of prostheses was mainly determined by material type, nominal energy, and density. Among these typical hip prostheses, ceramic prosthesis introduces the lowest dose perturbations.

关键词：髋关节剂量学假体放射治疗扰动效应 Geant4 X射线剂量直线加速器

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

STUDIES ON THE DEMETHYLATION-ALKYLATION REACTION OF ACETOPHENONES VIA 2-(1,3-DITHIAN-2-YLIDENE)-1-ARYLETHENONES

引用

Chinese Chemical Letters 1993年第4期4卷 299-302页

作者： Qun LIU bai ling XU Hong Wu ZHAO Department of Chemistry,Northeast Normal University,Changchun 130024

2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 were converted to the ***(5).The entire process represent a demethylation— alkylation reaction of *** mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols(4)was discussed.

关键词： ARYLETHENONES DITHIAN-2-YLIDENE STUDIES ON THE DEMETHYLATION-ALKYLATION REACTION OF ACETOPHENONES VIA 2 VIA

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

火电厂重要辅助设备可靠性状态识别研究

引用

热力发电 2017年第11期46卷 25-31页

作者：白翎中国神华能源股份有限公司国华电力分公司北京100025

现行火电厂辅助设备可靠性状态划分沿用主机划分标准,不能反应设备或部件发生异常但仍然坚持运行的可靠性状态。本文将辅助设备运行状态细化为健康运行状态及非健康运行状态,并定义了出力不足型、摩擦卡涩型、堵塞泄漏型和性能不足型4... 详细信息

现行火电厂辅助设备可靠性状态划分沿用主机划分标准,不能反应设备或部件发生异常但仍然坚持运行的可靠性状态。本文将辅助设备运行状态细化为健康运行状态及非健康运行状态,并定义了出力不足型、摩擦卡涩型、堵塞泄漏型和性能不足型4种非健康运行状态。通过对34台机组近三年的辅助设备故障数据进行分析,形成设备非健康状态的识别标准。实证应用结果表明,本文提出的划分方法能更精确地反映辅助设备运行的可靠程度,为辅助设备的管理提供依据和保障。

关键词：辅助设备可靠性非健康运行状态故障识别状态评价火电厂

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

"天堂共和国":《黑暗物质》中非人类意识与共同体想象

引用

外国语文 2022年第5期38卷 9-18页

作者：柏灵华中农业大学外国语学院湖北武汉430079

菲利普·普尔曼的《黑暗物质》三部曲创造了众多非人类角色和非人类世界。平行世界里的非人类叙事形成了成长主线外的另一条情节线:人与非人类建立反抗同盟,推翻宗教集权,建立"天堂共和国"。这条情节线以"共同体"为核心,着眼于非人类的... 详细信息

菲利普·普尔曼的《黑暗物质》三部曲创造了众多非人类角色和非人类世界。平行世界里的非人类叙事形成了成长主线外的另一条情节线:人与非人类建立反抗同盟,推翻宗教集权,建立"天堂共和国"。这条情节线以"共同体"为核心,着眼于非人类的意识刻画,以此反思人文范式下意识的超验性以及由此导致的排他性认同机制;小说通过非人类重置意识的物本源,建构意识的具身性,突破人与非人类的界限,提供更具包容性的理想共同体想象。

关键词：《黑暗物质》非人类意识共同体

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

SPH Modeling of Droplet Impact on Solid Boundary

引用

Transactions of Tianjin University 2014年第2期20卷 112-117页

作者：李大鸣白玲李玲玲赵明宇 State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University Hebei Research Institute of Investigation and Design of Water Conservancy and Hydropower

A droplet undergoes spreading,rebounding or splashing when it impacts solid boundary,which is a typical phenomenon of free surface flow that exists widely in modern *** particle hydrodynamics(SPH)method is applied to numerically study the dynamical behaviors of the droplet impacting solid boundary,and both the spreading and rebounding phenomena of the droplet are reproduced in the *** droplet deformation,flow fields and pressure fields inside the droplet at different moments are *** important factors,the initial velocity and diameter,are discussed in determining the maximum spreading factor,revealing that the maximum spreading factor increases with the increase of the impact velocity and droplet diameter respectively.

关键词： SPH model droplet impact solid boundary maximum spreading factor

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Role of Glutamine in the Mediation of E-cadherin, p120-catenin and Inflammation in Ventilator-induced Lung Injury

引用

Chinese Medical Journal 2018年第7期131卷 804-812页

作者： Jian-Lei Qiu bai-ling Song Yu-Juan Wang Fu-Tao Zhang Yue-Lan Wang Department of Anesthesiology Shandong Provincial Qianfoshan Hospital Shandong University Jinan Shandong 250014 China Department of Anesthesiology Dezhou People's Hospital Dezhou Shandong 253014 China Department of Surgery Rizhao People's Hospital Rizhao Shandong 276826 China Department of Anesthesiology Rizhao People's Hospital Rizhao Shandong 276826 China Department of Emergency Dezhou People's Hospital Dezhou Shandong 253014 China

Background： Ventilator-induced lung injury （VILI） is commonly associated with barrier dysfunction and inflammation reaction. Glutamine could ameliorate VILI, but its role has not been fully elucidated, This study examined the relationship between inflammatory cytokines （interleukin JILl-6, tumor necrosis factor [TNF]-α, and IL-10） and adherens junctions （E-cadherin, p 120-catenin）, which were ameliorated by glutamine in VILI, both in vitro and in vivo. Methods： For the in vivo study, 30 healthy C57BL/6 mice weighing 25-30 g were randomly divided into five groups with random number table （n = 6 in each group）： control （Group C）; low tidal volume （Group L）; low tidal volume ＋ glutamine （Group L ＋ G）; high tidal volume （Group H）; and high tidal volume ＋ glutamine （Group H ＋ G）. Mice in all groups, except Group C, underwent mechanical ventilation for 4 h. For the in vitro study, mouse lung epithelial 12 （MLE- 12） cells pretreated with glutamine underwent cyclic stretching at 20% for 4 h. Cell lysate and lung tissue were obtained to detect the junction proteins, inflammatory cytokines, and lung pathological changes by the Western blotting, cytokine assay, hematoxylin and eosin staining, and immunofluorescence. Results： In vivo, compared with Group C, total cell counts （t= -28.182, P 〈 0.01）, the percentage of neutrophils （t = -28.095, P 〈 0.01）, IL-6 （t = -28.296, P 〈 0.01 ）, and TNF-α（t = - 19.812, P 〈 0.01 ） in bronchoalveolar lavage （BAL） fluid, lung injury scores （t = -6.708, P 〈 0.01）, and the wet-to-dry ratio （t = - 15.595, P 〈 0.01 ） were increased in Group H; IL- 10 in BAL fluid （t = 9.093, P 〈 0.01 ） and the expression of E-cadherin （t= 10.044, P 〈 0.01） and p120-catenin （t = 13.218, P 〈 0.01） were decreased in Group H. Compared with Group H, total cell counts （t - 14.844, P 〈 0.01 ）, the percentage of neutrophils （t = 18.077, P 〈 0.0 l ）, IL-6 （t - 18.007, P 〈 0.01 ）, and TNF-α （t =1 0.171, P 〈 0.01 ） in BAL fluid were decreased in Group H ＋ G; IL-10 in BAL flu

关键词： Adherens Junctions Glutamine Inflammatory Cytokines Ventilation-induced Lung Injury

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于Gauss伪谱法的临近空间飞行器上升段轨迹优化

引用

宇航学报 2010年第7期31卷 1775-1781页

作者：宗群田栢苓窦立谦天津大学电气工程与自动化学院天津300072

综合考虑密度变化、声速变化、发动机推力变化及地球引力等因素对飞行轨迹的影响,研究了与实际飞行环境更加相符的临近空间飞行器燃料最优爬升轨迹。针对该问题在气动数据处理和优化求解上存在的困难,提出一种基于Gauss伪谱法(Gauss Pse... 详细信息

综合考虑密度变化、声速变化、发动机推力变化及地球引力等因素对飞行轨迹的影响,研究了与实际飞行环境更加相符的临近空间飞行器燃料最优爬升轨迹。针对该问题在气动数据处理和优化求解上存在的困难,提出一种基于Gauss伪谱法(Gauss Pseudospectral Method,GPM)的求解策略。首先,依据气动数据特点,设计拟合模型对气动参数进行高精度拟合;其次,为避免间接法和传统直接法的缺点,将Gauss伪谱法和序贯二次规划(Sequential Quadratic Programming,SQP)相结合,对存在边值及加速度约束的轨迹优化问题进行求解,获得最优飞行轨迹。仿真结果表明,在更为真实的飞行环境下,利用GPM和SQP相结合的方法可在5.83s获得一条精度为10-4～10-6左右的飞行轨迹。

关键词：临近空间飞行器上升段轨迹优化气动数据 Gauss伪谱法序贯二次规划

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

非线性系统全状态线性化内模扰动抑制

引用

电子科技大学学报 2014年第1期43卷 71-75页

作者：雷靖白雪玲云南民族大学数学与计算机科学学院昆明650500 云南省软件工程重点实验室昆明650091 日照职业技术学院机电工程学院山东日照276826

运用全状态线性化方法对在外部扰动持续作用下的非线性系统设计了扰动抑制控制器,利用非线性控制项消除开环系统的非线性因素。根据内模原理构造与扰动动态特性相同的内模补偿器,再利用Pontryagin极小值原理对增广系统设计最优调节器,... 详细信息

运用全状态线性化方法对在外部扰动持续作用下的非线性系统设计了扰动抑制控制器,利用非线性控制项消除开环系统的非线性因素。根据内模原理构造与扰动动态特性相同的内模补偿器,再利用Pontryagin极小值原理对增广系统设计最优调节器,得到非线性的内模扰动抑制控制器,其中的内模补偿控制项抵消了扰动对系统的影响。仿真中使用非线性内模扰动抑制控制器与非线性前馈反馈扰动抑制控制器进行比较,结果证明前者能够消除非线性因素影响且实现无静差扰动抑制。

关键词：扰动抑制全状态线性化内模原理非线性系统最优控制

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：