检索结果-南通市图书馆

The emerging role of nitric oxide in the synaptic dysfunction of vascular dementia

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 402-415页

作者： Xiaorong zhang Zhiying Chen Yinyi Xiong Qin Zhou Ling-Qiang Zhu Dan Liu Department of Pathology Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi ProvinceChina Jiujiang Clinical Precision Medicine Research Center JiujiangJiangxi ProvinceChina Center for Cognitive science and Transdisciplinary studies Jiujiang UniversityJiangxi ProvinceChina Department of Neurology Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi ProvinceChina Department of Rehabilitation Affiliated Hospital of Jiujiang UniversityJiujiangJiangxi ProvinceChina Department of Pathophysiology School of Basic MedicineTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina

With an increase in global aging,the number of people affected by cerebrovascular diseases is also increasing,and the incidence of vascular dementia-closely related to cerebrovascular risk-is increasing at an epidemic ***,few therapeutic options exist that can markedly improve the cognitive impairment and prognosis of vascular dementia *** in Alzheimer’s disease and other neurological disorders,synaptic dysfunction is recognized as the main reason for cognitive *** oxide is one of the ubiquitous gaseous cellular mes.engers involved in multiple physiological and pathological processes of the central nervous ***,nitric oxide has been implicated in regulating synaptic plasticity and plays an important role in the pathogenesis of vascular *** review introduces in detail the emerging role of nitric oxide in physiological and pathological states of vascular dementia and summarizes the diverse effects of nitric oxide on different aspects of synaptic dysfunction,neuroinflammation,oxidative stress,and blood-brain barrier dysfunction that underlie the progress of vascular ***,we propose that targeting the nitric oxide-sGC-cGMP pathway using certain specific approaches may provide a novel therapeutic strategy for vascular dementia.

关键词： endoplasmic reticulum stress endothelial nitric oxide synthase gene therapy nitric oxide NO-sGC-cGMP pathway synaptic dysfunction vascular dementia

THE ROLE OF HYDROGEN-BONDING INTERACTION IN POLY(VINYL ALCOHOL)/POLY(ACRYLIC ACID) BLENDING sOLUTIONs AND THEIR FILMs

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2010年第6期28卷 903-911页

作者： nan-xi Chen Jun-hua zhang state Key Laboratory of Polymer Materials.engineering of China Sichuan UniversityChengdu 610065China

The aim of this work is to investigate the hydrogen-bonding interaction in poly(vinyl alcohol)(PVA)/poly(acrylic acid)(PAA) blending system and its influence on rheological properties in solution and the physical properties in solid state. Introducing PAA into PVA solutions resulted in a thickening behavior of blend *** viscosity of the solutions increased with PAA content increasing,and a maximum viscosity could be obtained when the ratio of PVA/PAA was 70/30. The intermolecular hydrogen-bonding and miscibility between PVA and PAA in solid state were investigated by differential scanning calorimetry(DsC),Fourier transform infrared spectroscopy(FTIR) and mechanical *** results displayed the great influence of introducing PAA on the properties of blending *** tensile strength increased from 89.31 MPa to 119.8 MPa and Young’s modulus improved by over 300%with increasing PAA concentration compared with those of pure PVA *** systematically studying the rheological behaviors of solutions and the physical properties of films,the influence of hydrogen-bonding in solutions and solid states were discussed.

关键词： Polymer blending Rheology Hydrogen-bonding Molecular network Miscibility

LBE simulation of impinging stream inside a T-junction mixer

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2018年第7期61卷 1038-1055页

作者： XU WenKai zhang QingChen GUI nan zhang ZiWei College of Mechanical and Transportation engineering China University of PetroleumBeijing 102249China Beijing National Railway Research&Design Institute of signal&Communication Co. Ltd Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

Lattice Boltzmann Equation(LBE) method is utilized to simulate impinging stream(Is) in a T-junction mixer using a TD2G9 model. It aims to investigate the influence of Reynolds number(Re), aspect ratio of outlet diameter to inlet diameter, ratio of opposite inlet velocities, and the thermal boundary conditions on flow, mixing and heat transfer characteristics. In particular, the vortex evolution, velocity distribution, mixing index and Nusselt number(Nu) distribution in the T-junction mixer are explored in details. Four types of vortices and flow regimes are observed. The instantaneous and time-averaged flow and thermal fields,including vortex structure, transition of flow regimes, streamline and the Nusselt number distribution are discussed. Distinct quantitative transitions, even for dramatic change, are observed near the critical Re. At a low or moderate aspect ratio, the symmetric coherent structure is observed in an unstable flow regime. At a larger aspect ratio, the flow in the T-mixer becomes turbulent and asymmetric. The unequal injections velocities of the nozzles impose significant influence on the flow structure,mixing and heat transfer in vertical tube. Using larger difference between the two inlet velocities can result in more obvious change in flow characteristics. Moreover, mixing index is found to be valid in evaluating the mixing degree under a sinusoidal inlet velocity.

关键词： impinging flow lattice Boltzmann method T-junction heat transfer flow characteristics

A new physical model on the capillary phenomenon of granular particles

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics.english Edition) 2019年第1期40卷 127-138页

作者： nan zhang Bin CHeng Hexi BAOYIN Department of Aerospace engineering Tsinghua University

similar to the capillary phenomenon of liquid, granular particles can move up to a certain height along a vertically vibrating tube. The certain height, which is called the equilibrium height, is related to some parameters, e.g., the inner diameter of the tube, the amplitude, and the vibration frequency. In this paper, a theoretical model is proposed to explain the physical origin of the capillary phenomenon and the effects of the inner diameter of the tube, the amplitude, and the vibration frequency on the equilibrium height. In this model, the volumes of the inflowing and outflowing particles in a vibration period are calculated, which can significantly broaden our understanding in the flow of particles in the bottom of the tube. In order to prove the assumption of this physical model that the particles in the bottom of the tube move in the form of sine, several experiments are conducted. The granular climbing heights at different granular positions and different time stages are measured. The results show that granules move in the form of sine, which almost coincides with the motion of the tube. Moreover, motivated by the sampling on the asteroid regolith based on this mechanism, the sampling efficiencies for various vibration amplitudes and frequencies are discussed based on the new proposed model. It is found that there is an optimum frequency at which sampling is the most effective.

关键词： granular matter vertical vibration nonlinear dynamics theoretical analysis

Detecting super-Nyquist-frequency gravitational waves using a pulsar timing array

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2016年第8期59卷 78-86页

作者： shu-Xu Yi shuang-nan zhang Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of sciences Beijing 100049 China space science Division National Astronomical Observatories of China Chinese Academy of Sciences Beijing 100012 China

The maximum frequency of gravitational waves(GWs) detectable with traditional pulsar timing methods is set by the Nyquist frequency( fNy) of the observation. Beyond this frequency, GWs leave no temporal-correlated signals; instead, they appear as white noise in the timing residuals. The variance of the GW-induced white noise is a function of the position of the pulsars relative to the GW source. By observing this unique functional form in the timing data, we propose that we can detect GWs of frequency >f_(Ny)(super-Nyquist frequency GWs; sNFGWs). We demonstrate the feasibility of the proposed method with simulated timing *** a selected dataset from the Parkes Pulsar Timing Array data release 1 and the North American nanohertz Observatory for Gravitational Waves publicly available datasets, we try to detect the signals from single sNFGW sources. The result is consistent with no GW detection with 65.5% probability. An all-sky map of the sensitivity of the selected pulsar timing array to single sNFGW sources is generated, and the position of the GW source where the selected pulsar timing array is most sensitive to is λ_s =.0.82,β_s =-1.03(rad); the corresponding minimum GW strain is h = 6.31 × 10^(-11) at f = 1 × 10^(-5) Hz.

关键词： gravitational wave pulsar black hole

术后腹腔粘连形成机制及间充质干细胞外泌体的治疗前景

在线全文

学校读者我要写书评

暂无评论

中国组织工程研究 2025年第1期29卷 147-155页

作者：张兴洲魏明董国强杜为罗依雯张楠天津市南开医院胃肠外科天津市300100 天津市南开医院妇产科天津市300100 天津市血液细胞治疗技术企业重点实验室天津市300100 天津医科大学临床学院天津市300270

背景:术后腹腔粘连的形成是一个复杂的过程,预防术后粘连是临床上亟待解决的问题。目的:旨在从细胞及分子水平分析粘连的发生机制,为间充质干细胞外泌体预防和治疗粘连提供理论依据。方法:以“腹腔粘连,盆腔粘连,术后粘连,上皮间充质转... 详细信息

背景:术后腹腔粘连的形成是一个复杂的过程,预防术后粘连是临床上亟待解决的问题。目的:旨在从细胞及分子水平分析粘连的发生机制,为间充质干细胞外泌体预防和治疗粘连提供理论依据。方法:以“腹腔粘连,盆腔粘连,术后粘连,上皮间充质转化,间充质干细胞,干细胞外泌体,间充质干细胞外泌体”为中文检索词,以“Abdominal adhesion,pelvic adhesion,postoperative adhesion,epithelial mesenchymal transformation,mesenchymal stem cell,stem cell exosomes,mesenchymal stem cell exosomes”为英文检索词,检索PubMed、中国知网和中国生物医学文献数据库,筛选各数据库建库至2023年8月发表的术后腹腔粘连及间充质干细胞外泌体干预研究的相关文章,并进行系统的整理分析,最终纳入54篇文献进行综述。结果与结论:(1)任何腹膜炎症、机械损伤、组织缺血和异物植入等病理因素均可引起腹膜表面的损伤,引起术后腹腔粘连;腹腔粘连的形成过程包括腹膜间皮细胞修复、炎性反应、纤溶系统及凝血途径等过程的相互作用,涉及多种细胞因子及信号通路,包括Wnt/β-catenin通路能诱导纤维化和血管生成,并与转化生长因子β/smads信号通路相互协同,能刺激成纤维细胞增殖,引起腹膜纤维化;同时,核转录因子kB信号通路上调细胞炎症因子的表达,促进成纤维细胞增生,组织纤维化的过程中发挥关键作用。(2)干细胞的旁分泌功能是目前以再生医学为基础的分子干预腹腔粘连的重要方向,可以参与作用于腹腔粘连中的多种复杂细胞因子及信号通路。(3)相对于传统治疗腹腔粘连的方法,间充质干细胞外泌体具有生物活性、使用安全、无需特殊培养和扩增、更低的免疫原性及较长的稳定性等优势,能通过多种途径引导一种正常的修复和愈合。(4)间充质干细胞外泌体在以往研究中均被证明可以参与调节粘连形成的上述各过程,在临床研究中显示出潜在的应用前景,但需要进一步临床研究以探索适当的间充质干细胞外泌体治疗方案,来解决临床转化的问题。

关键词：术后腹腔粘连上皮间质转化炎症反应纤溶系统间充质干细胞外泌体肿瘤坏死因子α 白细胞介素生长因子转化生长因子β/smads信号通路 Wnt/β-catenin 核转录因子kB信号通路

OPTIMAL AND INCENTIVE COMPATIBLE PRICING FOR HETEROGENEOUs PERIODs

在线全文

学校读者我要写书评

暂无评论

Journal of systems science and systems.engineering 2008年第1期17卷 50-65页

作者： Jian CHEN nan zhang shuo HUANG Research Center for Contemporary Management Key Research Institute of Humanities and Social Sciences at Universities School of Economics and Management Tsinghua University Beijing 100084 China

This paper studies a service firm whose business time can be divided into several periods, each providing different value to customers. Heterogeneous service is a major reason resulting in imbalances between supply and demand. since customers differ in their degree of impatience, firrns can use differential pricing mechanisms to optimize their objectives and match supply with demand in each period, by inducing customers to choose different periods. We study two types of firrns, an internal firm, the objective of which is to maximize the system＇s （including the f＇nan and all the customers） total net value, and a commercial firm, which aims to optimize its own profit. Though impatience factors are customers＇ private information, for each type of firm, we derive the optimal incentive compatible pricing policy, under which all the coming customers will follow the firm＇s assignment, that is, patient customers will buy the service in high-value periods, but their waiting time will be longer, while impatient customers will enter into the low-value periods, but they will be compensated by shorter waiting times. Furthermore, in the internal firm, we also prove that this mechanism enables the decentralization of decisions, while maintaining centralized system-wide optimality. Numerical analysis shows that when there is sufficient capacity, the internal firm does not always need to set lower prices than the commercial firm in every period.

关键词： Delay cost queuing differential pricing information asymmetry incentive compatibility

Constellation shaping optimization for nonlinearity mitigation in CAP UVLC system

在线全文

学校读者我要写书评

暂无评论

science China(Information sciences) 2023年第9期66卷 274-290页

作者： Junlian JIA Junwen zhang nan CHI Key Laboratory for Information science of Electromagnetic Waves(MoE) Fudan University shanghai engineering Research Center of Low-Earth-Orbit satellite Communication and Applications shanghai Collaborative Innovation Center of Low-Earth-Orbit satellite Communication Technology Peng Cheng Laboratory

In the sixth-generation communication(6G), wireless communication will cover not only conventional air links but also underwater links. Underwater visible light communication(UVLC) is an expected technique that achieves a high data rate. However, UVLC systems suffer from severe nonlinear distortions for the high-power transmitting, thus nonlinear compensation is vital to the system. Carrier-less amplitude and phase(CAP) modulation is a promising modulation, especially for the scenes with high nonlinear *** this paper, for the first time, we proposed a constellation optimization method for the UVLC system supporting the native artificial intelligence in 6G. The proposed framework, based on the complete process of the CAP modulation and demodulation, fulfills an end-to-end learning scheme with a neural network at the transmitter side and the conventional demodulation processes at the receiver side. A loss function is further designed to support the training without needing a fixed signal-to-noise ratio(sNR). The proposed framework is simulated and then tested in an experiment. In a 1.2-meter nonlinear UVLC channel, compared with 1.5 Gbit/s supported by the conventional grid encoding, the proposed method brings an extra 200 Mbit/s data rate.

关键词： underwater visible light communication nonlinearity compensation constellation optimization

CFD simulation of the effects of a suspension section on the hydrodynamics of a circulating fluidized bed

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Particuology 2019年第2期17卷 1-8页

作者： Cenfan Liu nan zhang Wei Wang state Key Laboratory of Multiphase Complex systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China China special Equipment Inspection and Research Institute Beijing 100029 China University of Chinese Academy of sciences Beijing 100049 China

Gas-solid two-phase flow in a circulating fluidized bed (CFB) is affected by operating conditions (e.g., superficial gas velocity, solids inventory), material properties and geometric factors, such as the entry and exit configuration. In particular, the suspension section, which is located between the riser bottom and the solids recycle inlet, affects the hydrodynamics in the riser significantly. However, the suspension section has received less attention compared with other geometric factors. Most computational fluid dynamics (CFD) simulations, especially two-dimensional simulations do not take this factor into account. We performed three-dimensional, full-loop CFD simulations with a drag coefficient that was determined by the energy-minimization multi-scale model, and investigated the flow behavior of two CFBs with different suspension-section lengths. The simulation resuits revealed that the axial profiles of voidage in the riser with a longer suspension section are more likely s-shaped, whereas those with shorter suspension sections decay exponentially. The dependences of solids flux on solids inventory differ in the two CFBs. A shorter suspension section may result in a smooth transition from dilute to dense transport without intermediate accumulative choki-ng, whereas a Ion ger suspe nsion section may lead to a choking transition. These simulation results are qualitatively consistent with the flow behaviors described in literature.

关键词： Computational fluid dynamics Fluidization Meso-scale Energy-minimization multi-scale suspension section