检索结果-南通市图书馆

Effects of total saponins of panax notoginseng on immature neuroblasts in the adult olfactory bulb following global cerebral ischemia/reperfusion

引用

Neural Regeneration Research 2015年第9期10卷 1450-1456页

作者： Xu He Feng-jun deng Jin-wen Ge Xiao-xin Yan Ai-hua pan zhi-yuan Li Department of Anatomy and Neurobiology School of Basic Medical Sciences Central South University Department of Anatomy Yiyang Medical College Department of Pharmacy Yiyang Medical College Department of Integrated Traditional and Western Medicine Hunan University of Traditional Chinese Medicine

The main active components extracted from panax notoginseng are total saponins. They have been shown to inhibit platelet aggregation, increase cerebral blood flow, improve neurological behavior, decrease infarct volume and promote proliferation and differentiation of neural stem cells in the hippocampus and lateral ventricles. However, there is a lack of studies on whether total saponins of panax notoginsertg have potential benefits on immature neuroblasts in the olfactory bulb following ischemia and reperfusion. This study established a rat model of global cerebral ischemia and reperfusion using four-vessel occlusion. Rats were administered total sa- ponins of panax notoginseng at 75 mg/kg intraperitoneally 30 minutes after ischemia then once a day, for either 7 or 14 days. Total saponins of panax notoginseng enhanced the number of dou- blecortin （DCX）＋ neural progenitor ceils and increased co-localization of DCX with neuronal nuclei and phosphorylated cAMP response element-binding/DCX＋ neural progenitor cells in the olfactory bulb at 7 and 14 days post ischemia. These findings indicate that following global brain ischemia/reperfusion, total saponins of panax notoginseng promote differentiation of DCX＋ cells expressing immature neuroblasts in the olfactory bulb and the underlying mechanism is related to the activation of the signaling pathway of cyclic adenosine monophosphate response element binding protein.

关键词： nerve regeneration total saponins of panax notoginseng cerebral ischemia/reperfusion immature neurons neurogenesis doublecortin olfactory bulb neural regeneration

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

The cooperation effect of Ni and Pt in the hydrogenation of acetic acid

引用

Frontiers of Chemical Science and Engineering 2022年第3期16卷 397-407页

作者： deng pan Jiahua Zhou Bo Peng Shengping Wang Yujun Zhao xinbin Ma Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin300072China SINOPEC Research Institute of Petroleum Processing(RIPP) Beijing100083China

The catalytic hydrogenation of carboxylic acid to alcohols is one of the important strategies for the conversion of ***,a series of Ni-doped PtSn catalysts were prepared,characterized and studied in the hydrogenation of acetic *** Ni dopant has a strong interaction with Pt,which promotes the hydrogen adsorption,providing an activated hydrogen-rich environment for the ***,the presence of Ni also improves the Pt dispersion,giving more accessible active sites for hydrogen *** cooperation of Pt and Ni significantly promotes the catalytic activity of the hydrogenation of acetic acid to *** a result,the catalyst with 0.1%Ni exhibits the best reaction activity,and its space time yield is twice as that of the PtSn/SiO2 *** provides a meaningful instruction on the catalyst design for the carboxylic acid hydrogenation.

关键词： acetic acid ethanol hydrogenation Pt Ni cooperation effect

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

Adsorptive interaction between typical VOCs and various topological zeolites:Mixture effect and mechanism

引用

Journal of Environmental Sciences 2024年第2期136卷 626-636页

作者： Bo Yu Hua deng Yuqin Lu Tingting pan Wenpo Shan Hong He Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Adsorption is one of the most feasible and effective methods to alleviate the volatile organic compounds(VOCs)***,the mixture effect and mechanism for competitive adsorption of VOCs on zeolites are barely *** this study,toluene,acetone,and ethyl acetate as prevalent VOCs species were removed by four potential zeolites(13X,USY,Beta,ZSM-5)in both single-and multi-component *** structure-property relationship between adsorbate-adsorbent pairs was revealed by X-ray diffraction,scanning electron microscopy,energy dispersive spectrometer,X-ray fluorescence,N_(2) adsorption and density function theory *** molecular polarity and volatility of VOCs species played key roles in adsorption and the dynamic uptakes were generally listed as follows:ethyl acetate>toluene>*** for the above VOCs mixtures,13X zeolite selectively adsorbed oxygenated VOCs rather than *** contrast,USY exhibited a preference to trap *** acetate could be readily enriched by ZSM-5 and Beta *** possible explanations and implications are discussed based on the subtle change in electron *** results obtained are vital for understanding the mixture effect of VOCs adsorption and may guide the selection of proper adsorbent for real applications.

关键词： Adsorption Zeolites VOCs Mixture effect DFT

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

基于光谱和神经网络模型的作物与杂草识别方法研究

引用

光谱学与光谱分析 2008年第5期28卷 1102-1106页

作者：朱登胜潘家志何勇金华职业技术学院信息工程学院浙江金华321017 浙江大学生物系统工程与食品科学学院浙江杭州310029

利用光谱技术来识别作物与杂草是精细农业中一个非常重要的研究内容，但光谱数据中含有大量冗余数据，如何预处理以及建立识别模型，是决定识别准确率的关键。利用在325-1075nm波段的光谱识别了三种杂草（牛筋草、凹头苋、空心莲子草）... 详细信息

利用光谱技术来识别作物与杂草是精细农业中一个非常重要的研究内容，但光谱数据中含有大量冗余数据，如何预处理以及建立识别模型，是决定识别准确率的关键。利用在325-1075nm波段的光谱识别了三种杂草（牛筋草、凹头苋、空心莲子草）与大豆幼苗。在幼苗生长的第三周与第六周分别采集杂草与作物的光谱，共378个样本。用其中的250个光谱样本，包括第一期和第二期采集的光谱样本，在采用db12小波经过三层分解后，将其小波系数作为输入数据建模，构造了一个径向基函数神经网络。然后，利用余下的光谱样本检验该模型的识别能力。结果表明，该模型对作物与杂草光谱具有极强的识别能力，只有3个第二期的牛筋草样本被判断为空心莲子草，其余的样本全部正确识别。这个结果表明，采用可见／近红外光谱识别大豆幼苗与三种伴随生长的杂草是可行的，同时也说明，随着作物的生长阶段的不同，其光谱的变化不会影响到种类识别。

关键词：近红外光谱 RBF人工神经网络识别杂草豆苗

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

Inhibition of microRNA-29b suppresses oxidative stress and reduces apoptosis in ischemic stroke

引用

Neural Regeneration Research 2022年第2期17卷 433-439页

作者： Yao-Hua Ma Wen-Jing deng zhi-Yi Luo Jing Jing Peng-Wei pan Yao-Bing Yao Yan-Bo Fang Jun-Fang Teng Neurological Intensive Care Unit the First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan ProvinceChina

MicroRNAs(miRNAs) regulate protein expression by antagonizing the translation of mRNAs and are effective regulators of normal nervous system development, function, and disease. Micro RNA-29 b(mi R-29 b) plays a broad and critical role in brain homeostasis. In this study, we tested the function of mi R-29 b in animal and cell models by inhibiting mi R-29 b expression. Mouse models of middle cerebral artery occlusion were established using the modified Zea-Longa suture method. Prior to modeling, 50 nmol/kg mi R-29 b antagomir was injected via the tail vein. Mi R-29 b expression was found to be abnormally increased in ischemic brain tissue. The inhibition of mi R-29 b expression decreased the neurological function score and reduced the cerebral infarction volume and cell apoptosis. In addition, the inhibition of mi R-29 b significantly decreased the malondialdehyde level, increased superoxide dismutase activity, and Bcl-2 expression, and inhibited Bax and Caspase3 expression. PC12 cells were treated with glutamate for 12 hours to establish in vitro cell models of ischemic stroke and then treated with the mi R-29 antagomir for 48 hours. The results revealed that mi R-29 b inhibition in PC12 cells increased Bcl-2 expression and inhibited cell apoptosis and oxidative damage. These findings suggest that the inhibition of mi R-29 b inhibits oxidative stress and cell apoptosis in ischemic stroke, producing therapeutic effects in ischemic stroke. This study was approved by the Laboratory Animal Care and Use Committee of the First Affiliated Hospital of Zhengzhou University(approval No. 201709276 S) on September 27, 2017.

关键词： Akt apoptosis cerebral artery occlusion ischemic stroke malondialdehyde microRNA-29b oxidative stress PI3K superoxide dismutase

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

Creating nitrogen-vacancy ensembles in diamond for coupling with flux qubit

引用

Chinese Physics B 2017年第2期26卷 75-79页

作者： Ya-Rui Zheng Jian xing Yan-Chun Chang zhi-Guang Yan Hui deng Yu-Lin Wu Li Lu xin-Yu pan Xiao-Bo Zhu Dong-Ning Zheng Institute of Physics Chinese Academy of Sciences Beijing 100190 China

Hybrid quantum system of negatively charged nitrogen–vacancy（NV^-） centers in diamond and superconducting qubits provide the possibility to extend the performances of both systems. In this work, we numerically simulate the coupling strength between NV^-ensembles and superconducting flux qubits and obtain a lower bound of 1016cm^（-3） for NV^-concentration to achieve a sufficiently strong coupling of 10 MHz when the gap between NV^-ensemble and flux qubit is 0. Moreover, we create NV^-ensembles in different types of diamonds by14^（N＋）and12（C＋）ion implantation, electron irradiation, and high temperature annealing. We obtain an NV^-concentration of 1.05 × 1016cm^（-3） in the diamond with1-ppm nitrogen impurity, which is expected to have a long coherence time for the low nitrogen impurity concentration. This shows a step toward performance improvement of flux qubit-NV^-hybrid system.

关键词： flux qubit nitrogen–vacancy center hybrid quantum system

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

Understanding nano effects in catalysis

引用

National Science Review 2015年第2期2卷 183-201页

作者： Fan Yang Dehui deng xiulian pan Qiang Fu xinhe Bao State Key Laboratory of Catalysis iChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Dalian Institute of Chemical PhysicsChinese Academy of Sciences

Catalysis, as a key and enabling technology, plays an increasingly important role in ields ranging from energy, environment and agriculture to health care. Rational design and synthesis of highly eicient catalysts has become the ultimate goal of catalysis research. hanks to the rapid development of nanoscience and nanotechnology, and in particular a theoretical understanding of the tuning of electronic structure in nanoscale systems, this element of design is becoming possible via precise control of nanoparticles' composition, morphology, structure and electronic states. At the same time, it is important to develop tools for in situ characterization of nanocatalysts under realistic reaction conditions, and for monitoring the dynamics of catalysis with high spatial, temporal and energy resolution. In this review, we discuss coninement efects in nanocatalysis, a concept that our group has put forward and developed over several years. Taking the conined catalytic systems of carbon nanotubes, metal-conined nano-oxides and 2D layered nanocatalysts as examples, we summarize and analyze the fundamental concepts, the research methods and some of the key scientiic issues involved in nanocatalysis. Moreover, we present a perspective on the challenges and opportunities in future research on nanocatalysis from the aspects of:(1) controlled synthesis of nanocatalysts and rational design of catalytically active centers;(2) in situ characterization of nanocatalysts and dynamics of catalytic processes;(3) computational chemistry with a complexity approximating that of experiments; and (4) scale-up and commercialization of nanocatalysts.

关键词： nanocatalysis coninement carbon nanotubes graphene 2D materials inverse catalysts computational chemistry in situ characterizati

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Revisiting the TALE repeat

引用

Protein & Cell 2014年第4期5卷 297-306页

作者： Dong deng Chuangye Yan Jianping Wu Xiaojing pan Nieng Yan State Key Laboratory of Bio-membrane and Membrane Biotechnology Center for Structural Biology School of Life Sciencesand School of Medicine Tsinghua-Peking Center for Life Sciences Beijing 100084 China Tsinghua-Peking-NIBS Joint Program Tsinghua University Beijing 100084 China

Transcription activator-like （TAL） effectors specifically bind to double stranded （ds） DNA through a central domain of tandem repeats. Each TAL effector （TALE） repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-rec- ognition hyper-variable residue. This new numbering system is consistent with the （=-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine （A） and guanine （G） by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity.

关键词： TAL effectors DNA recognition plasticity

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

Numerical simulation of a thermal-bubble actuated diffuser-nozzle valveless pump

引用

Science China(Technological Sciences) 2009年第10期52卷 2967-2972页

作者： pan LiangMing deng JieWen YUAN DeWen CHEN DeQi ZHANG JunQi School of Power Engineering Chongqing UniversityChongqing 400044China

A valveless micropump actuated by thermal bubbles which are generated by an electrode heater mounted with a pair of diffuser nozzles has been numerically studied by commercial CFD software FLUENT. The relationships between the net flow rate and the superheating and heat supplying frequency have been investigated. The depth of the diffuser-nozzle micropump is 200 μm, the diameter of the actuating chamber is 1 mm, and a pair of diffuser nozzles whose gap has been expanded from 30 μm to 274 μm with an open angle of 7° are connected to the actuating chamber. The working fluid is methanol. In the numerical simulation, the flow pattern is laminar. The results show that the pump has different optimal driving frequencies at different superheating. A cycle resulting from bubble growth and shrinking costs more time at higher superheating temperature; different superheating has different optimal driving frequency; when the superheating increases, the maximum volume flow rate and the maximum pump pressure will increase simultaneously, and the optimal driving frequency decreases as well, the maximum volume flow rate and pump pressure also have the same tendency; in the condition of uncontrolled condensing, the bubble shrinking process is longer than the growth process, thus it is the determining factor to affect the pump performance. The maximum volume flow rate is 9.02 μL/min at ΔT = 15°C, and the maximum pump pressure is 680 Pa. With the increase of wall superheat, cycle including the bubble growth and condensation will become longer, resulting in a significant impact on the pumping flow; different wall superheat has different optimized frequency, increasing superheat will bring increased pumping flow and pump pressure, the optimized driving frequency will be reduced; liquid supply phase is longer than pumping phase.

关键词： thermal bubble actuating valveless diffuser-nozzle micropump numerical simulation

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

Multi‑color Tunable and White Circularly Polarized Luminescent Composite Nanofibers Electrospun from Chiral Helical Polymer

引用

Advanced Fiber Materials 2022年第6期4卷 1632-1644页

作者： Pengpeng Li Xiaobin Gao Biao Zhao Kai pan Jianping deng State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical Technology100029 BeijingChina College of Materials Science and Engineering Beijing University of Chemical Technology100029 BeijingChina

Circularly polarized luminescence(CPL)-active nanomaterials have attracted tremendous ***,it is still a big challenge to conveniently fabricate multi-color and white CPL-active nanomaterials on a large ***,a simple and scalable approach to achieve the above goals is *** CPL-active nanofibers are fabricated from chiral helical substituted polyacetylene,achiral fluorescent dyes and polyacrylonitrile via uniaxial electrospinning;the highest luminescence dissymmetry factor(glum)of the resulting nanofibers can reach 10^(−2).Furthermore,white CPL-active nanofibers are obtained by coaxial electrospinning,in which the resulting core-shell structure has excellent adjustability and can be utilized to physically isolate different fluorescent dyes to reduce energy transfer efficiency;therefore,stable white CPL emissions can be achieved with high g_(lum) values up to 10^(−3).Notably,the prepared white-emission CPL nanofibrous films show bright white circularly polarized light when coated on UV chips,demonstrating their future application in constructing low-cost and flexible light-emitting devices such as circularly polarized light-emitting diodes.

关键词： Chiral helical polymer Nanofiber Multi-color circularly polarized luminescence White-light emission

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

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：