ITO玻璃芯片上温度分布对成肌细胞生长增殖的影响

为了研究不同温度对小鼠成肌细胞生长增殖的影响,在ITO玻璃芯片上加载电场形成一定的温度分布。在不同温度(38、39、40和41℃)所对应的区域加工相同尺寸的PDMS微型培养腔室用于小鼠成肌细胞的培养。通过对芯片上培养的小鼠成肌细胞连续5 d的热刺激(30 min/d),研究不同温度短期热刺激对成肌细胞增殖的影响。细胞形态显微观察和流式细胞仪检测结果表明,一定的温度刺激对小鼠成肌细胞的增殖有促进作用,其中40℃刺激后的细胞数目增加最明显。在总刺激时间(30 min)相同情况下,短时多次热刺激的效果更理想,细胞增殖指数最高可达38.39。     

智能响应蓝相液晶光子晶体

具有刺激响应性的智能驱动材料已成为材料科学领域的研究热点之一。液晶的超分子自组装结构与其刺激响应特性使其在新型智能功能材料的开发应用上具有天然优势。蓝相液晶由于其独特的三维超分子自组装结构、软物质特性以及可见光波段的选择性光反射,被认为是最具潜力的智能光子晶体材料之一。在温度、光照、电场、湿度等外场刺激作用下,蓝相超分子自组装结构的晶体学参数或相态非常容易发生变化,造成光子带隙的改变进而呈现出反射颜色的变化。因此,蓝相的外场响应性能及在智能材料上的应用引起了研究者的广泛关注。本文综述了智能响应蓝相液晶光子晶体外场响应性能方面的前沿动态,对蓝相液晶光子晶体的光、磁、电、力、湿度响应等方面取得的系列重要的研究成果进行了总结,并对该领域目前存在的挑战以及未来发展趋势做出展望。     

Large-Scale Turbulent Vortical Structures inside a Sudden Expansion Cylinder Chamber

A large eddy simulation (LES) is performed for turbulent flow around a bluff body inside a sudden expansion cylinder chamber, a configuration which resembles a premixed gas turbine combustor. To promote turbulent mixing and to accommodate flame stability, a flame holder is installed inside the combustion chamber. The Smagorinsky model and the Lagrangian dynamic subgrid-scale model are employed and tested. The calculated Reynolds number is 5,000 based on the bulk velocity and the diameter of inlet pipe. The simulation code is constructed by using a general coordinate system based on the physical contravariant velocity components. The predicted turbulent statistics are evaluated by comparing with the laser-doppler velocimetry (LDV) measurement data. The agreement of LES with the experimental data is shown to be satisfactory. Emphasis is placed on the time-dependent evolutions of turbulent vortical structures behind the flame holder. The numerical flow visualizations depict the behavior of large-scale vortices. The turbulent behavior behind the flame holder is analyzed by visualizing the sectional views of vortical structure. This revised version was published online in July 2006 with corrections to the Cover Date.     

Registering and analyzing rat fMRI data in the stereotaxic framework by exploiting intrinsic anatomical features

The value of analyzing neuroimaging data on a group level has been well established in human studies. However, there is no standard procedure for registering and analyzing functional magnetic resonance imaging (fMRI) data into common space in rodent fMRI studies. An approach for performing rat imaging data analysis in the stereotaxic framework is presented. This method is rooted in the biological observation that the skull shape and size of rat brain are essentially the same as long as their weights are within certain range. Registration is performed using rigid-body transformations without scaling or shearing, preserving the unique properties of the stable shape and size inherent in rat brain structure. Also, it does not require brain tissue masking and is not biased towards surface coil sensitivity profile. A standard rat brain atlas is used to facilitate the identification of activated areas in common space, allowing accurate region of interest analysis. This technique is evaluated from a group of rats (n=11) undergoing routine MRI scans; the registration accuracy is estimated to be within 400 μm. The analysis of fMRI data acquired with an electrical forepaw stimulation model demonstrates the utility of this technique. The method is implemented within the Analysis of Functional NeuroImages (AFNI) framework and can be readily extended to other studies.     

Microfluidic cell arrays for metabolic monitoring of stimulated cardiomyocytes

An array of PDMS microchambers was aligned to an array of sensor electrodes and stimulating microelectrodes, which was used for the electrochemical monitoring of the metabolic activity of single isolated adult ventricular myocytes inside the chamber array, stimulated within a transient electric field. The effect of the accumulation of metabolic byproducts in the limited extracellular volume of the picolitre chambers was demonstrated by measuring single muscle cell contraction optically, while concomitant changes in intracellular calcium transients and pH were recorded independently using fluorescent indicator dyes. Both the amplitude of the cell shortening and the magnitude of the intracellular calcium transients decreased over time and both nearly ceased after 20 min of continuous stimulation in the limited extracellullar volume. The intracellular pH decreased gradually during 20 min of continuous stimulation after which a dramatic pH drop was observed, indicating the breakdown of the intracellular buffering capacity. After continuous stimulation, intracellular lactate was released into the microchamber through cell electroporation and was detected electrochemically at a lactate microbiosensor, within the chamber. A mitochondrial uncoupler was used to mimic ischaemia and thus to enhance the cellular content of lactate. Under these circumstances, intracellular lactate concentrations were found to have risen to ～15 mM. This array system has the potential of simultaneous electrochemical and optical monitoring of extracellular and intracellular metabolites from single beating heart cells at a controlled metabolic state.     

Network pharmacology analysis of Chaihu Lizhong Tang treating non-alcoholic fatty liver disease

BackgroundIn this study, the network pharmacological methods were used to predict the target of active components of Chaihu Lizhong Tang (CHLZT) in the treatment of non-alcoholic fatty liver disease (NAFLD).MethodThe active components of "CHLZT", their targets, and NAFLD related targets were screened by multiple databases, and the potential targets of "CHLZT" in the treatment of NAFLD were predicted. The active component-target network of "CHLZT" was constructed by Cytoscape software. The potential target of "CHLZT" for the treatment of NAFLD constructed protein-protein interaction (PPI) network in the Search Tool for the Retrieval of Interacting Genes Database (STRING). The hub genes of “CHLZT” in the treatment of NAFLD were screened by network topological parameters, and the results were verified by molecular docking. "ClusterProfiler" in R was used for Gene Ontology (GO) analysis and KEGG pathway enrichment analysis.ResultsOB ≥ 30 % and DL ≥ 0.18 were selected as the screening criteria of active components. A total of 83 active components and 456 targets were selected. Based on the evaluation of topological parameters of degree network, five hub genes for interaction with "CHLZT" therapy for NAFLD were screened, that is, AKT1, ALB, IL6, EGFR, and CASP3. The results of molecular docking showed that the active components in "CHLZT" had a good binding ability with the key targets. The enrichment analysis results showed that the treatment of NAFLD with "CHLZT" mainly involved in cofactor binding, protease binding, AGE-RAGE signaling pathway in diabetic complications, and IL-17 signaling pathway, which mediated the potential mechanism of "CHLZT" intervention in NAFLD.ConclusionThe molecular mechanism of "CHLZT" in the treatment of NAFLD indicated the synergistic features of multi-component, multi-target, and multi-pathway of traditional Chinese medicine, which provided an important scientific basis for further elucidating the mechanism of "CHLZT" in the treatment of NAFLD.     

考虑互惠公平的创新顾客激励契约研究

基于公平偏好理论的互惠公平,从创新顾客的互惠偏好程度、激励契约类型与激励效果的关系入手,构建创新顾客参与企业创新活动的激励模型。通过模型求解和分析,探讨激励契约的外部性和互惠关系对于激励效果的影响;此外,进一步分析如何联合经济激励和心理激励,降低企业获得创新顾客高努力投入的成本;最后,通过仿真实验,验证模型分析结果。研究发现:当创新顾客之间出现互惠关系时,最优激励契约取决于创新顾客心理偏好与风险态度之间的相互作用:当创新顾客的风险规避程度较低时,最优激励契约为相对绩效契约;当创新顾客的风险规避程度较高时,最优激励契约为团队报酬契约。     

fMRI在经颅直流电刺激研究中的应用进展

经颅直流电刺激（tDCS）是一种新颖的神经系统疾病治疗手段,可非侵入性调控中枢神经活动.它具有安全、成本低、疗效显著等特点,因此在神经科学等领域被大量研究和应用.功能磁共振成像（fMRI）具备高时空分辨率的优势,近年来被广泛用于tDCS治疗效果的评估及其作用机制的研究.本文从临床研究与动物模型实验两方面总结fMRI技术应用于tDCS研究中的最新进展,并讨论其应用前景.     

肿瘤微环境刺激响应型上转换光动力诊疗体系的构建和发展

光动力治疗是一种新型的非侵入式肿瘤治疗方法,具有创伤性和毒性小、选择性好、无耐药性、可重复治疗等突出优点,在癌症的治疗上取得了显著的成效.为了增加光动力治疗的组织穿透深度,研究者提出构建基于上转换纳米颗粒（upconversion nanoparticles,UCNPs）的光动力诊疗探针（简称上转换光动力诊疗探针）.基于发光共振能量转移过程,上转换光动力诊疗探针利用UCNPs在近红外光激发下发射的荧光激活负载的光敏剂发挥光动力疗效,有助于实现深层肿瘤的治疗.新型的上转换光动力诊疗探针通过多功能一体化的结构组合设计可以实现靶向运输、成像诊断以及刺激响应的按需治疗,是未来纳米医药发展的必然趋势.目前,研究者越来越关注构建基于肿瘤微环境刺激响应型上转换光动力诊疗体系,以提高治疗体系的靶向性,改善光动力治疗效果,并减小对周围正常组织的毒性.本工作主要讨论了基于pH、酶及过氧化氢刺激响应型上转换光动力诊疗体系的构建和发展,并对其发展前景进行了展望.