摘要： Quantifying multi-molecular complex assembly in specific cytoplasmic compartments is crucial to understand how cells use assembly/disassembly of these complexes to control function. Currently, biophysical methods like Fluorescence Resonance Energy Transfer and Fluorescence Correlation Spectroscopy provide quantitative measurements of direct protein-protein interactions, while traditional biochemical approaches such as sub-cellular fractionation and immunoprecipitation remain the main approaches used to study multi-protein complex assembly/disassembly dynamics. In this article, we validate and quantify multi-protein adherens junction complex assembly in situ using light microscopy and Fluorescence Covariance Analysis. Utilizing specific fluorescently-labeled protein pairs, we quantified various stages of adherens junction complex assembly, the multiprotein complex regulating epithelial tissue structure and function following de novo cell-cell contact. We demonstrate: minimal cadherin-catenin complex assembly in the perinuclear cytoplasm and subsequent localization to the cell-cell contact zone, assembly of adherens junction complexes, acto-myosin tension-mediated anchoring, and adherens junction maturation following de novo cell-cell contact. Finally applying Fluorescence Covariance Analysis in live cells expressing fluorescently tagged adherens junction complex proteins, we also quantified adherens junction complex assembly dynamics during epithelial monolayer formation.

关键词： Biosorption   Isotherm   Methylene blue   Seaweed   Water treatment  

摘要： The present research was undertaken in order to examine the feasibility of a novel biosorbent Gracilaria corticata (red seaweed) for the removal of methylene blue (MB) from aqueous solutions. Biosorption studies were conducted as a function of equilibrium pH, initial dye concentration, and biosorbent dosage. It was identified that the biosorption capacity of G. corticata strongly depends on solution equilibrium pH and highest biosorption capacity of 28.9mg/g was observed at pH 8. The Fourier transform infrared analysis confirmed interaction of dye molecules with binding sites on the surface of G. corticata. Also, the scanning electron microscopy images revealed morphological cell surface changes after biosorption of MB onto G. corticata. The removal efficiency of MB from solution with an initial concentration of 150mg/L varied from 50.8 to 94.9% for an increase of the seaweed dose from 2 to 5g/L. Kinetic study was performed using pseudo-first- and pseudo-second-order models, but higher degree of correlation coefficient and low % error values were obtained for the pseudo-second-order kinetic model. Experimental isotherms were favorable and the data were analyzed using the Langmuir, Freundlich, Redlich-Peterson, and Toth models, with the latter successfully described MB isotherm with high correlation coefficient and low % error values. The biosorption capacity of G. corticata toward MB was determined as 95.41mg/g, according to the Langmuir model.

关键词： Bulk metallic glass   Carbon nanotube   Molecular dynamics   Nanocomposite  

摘要： Carbon nanotubes (CNTs) have been widely used to strengthen different types of materials including polymers, ceramics, and metals due to their extraordinarily high strength. In this work, we investigated the influence of CNTs on the mechanical characteristics of amorphous metallic glasses by using molecular dynamics simulations. We constructed long (continuous) and short (discontinuous) CNT-reinforced metallic glass nanocomposites, determined their stress-strain responses and elastic modulus, and compared their tensile and compressive behaviors with monolithic metallic glasses. It was found that long CNTs dramatically increased the stiffness and yield strength of the metallic glass, and improved their elastic region of deformation and ability to absorb energy. In contrast, metallic glasses reinforced with short CNTs showed almost no improvement of mechanical properties. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Portland cement phases   Molecular dynamics   Mechanical properties   Simulation   Force fields  

摘要： Recent advances in concrete industry have highlighted the need for accurate knowledge about its nanostructure and mechanical properties. Cement, as the main material of concrete, is of great importance. Additionally, using nano-scale calculation methods have led to better understanding of materials functionalities. In this paper, it is tried to estimate the mechanical properties of cement clinker phases by atomistic simulation and via molecular dynamics method. To achieve this goal, C2S, C3S, C(3)A, and C(4)AF were studied as major phases and periclase, calcium oxide, arcanite, aphthitalite, and thenardite were also selected as minor phases. Furthermore, the eight COMPASS, COMPASSII, CLAYFF, Dreiding, Universal, CVFF, PCFF and INTERFACE force fields were used for atomistic simulations. Finally, the bulk modulus, shear modulus, Young's modulus, Poisson ratio and compressibility properties were calculated by formulas of elasticity theory. Obtained results were compared with those in the pertinent literature. The results revealed that using molecular dynamics method was suitable in estimating mechanical properties of cement phases. These findings might be applied in larger scales and also multi-scale simulations. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Opto-mechanical system   Nonclassical properties   Four-headed cat state (4HCS)   Wigner function   Time-dependent displaced number state  

摘要： The nonlinear interaction between an optical field and a mechanical resonator of an opto-mechanical system plays an important role in quantum optics and quantum information. This work applies the nonlinearity of opto-mechanical system to generate a nonclassical state for an initial state composed of four-headed cat state of photonic mode and number state of mechanical mode. It is interesting to find that the Wigner function of a mechanical mode is composed of finite Wigner functions of time-dependent displaced number states, which is very useful in quantum information process. Furthermore, nonclassical properties of the photonic and mechanical modes are investigated by using Wigner function. An interesting result is that the negative volume of Wigner function for the photonic (or mechanical) mode increases with parameter alpha (or k), which means that the larger initial value of photonic (or mechanical) mode will improve the nonclassicality of the photonic (or mechanical) mode. We also investigate the influence of different initial photonic states on the nonclassicality of mechanical and photonic modes. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Anatomy   Biochemistry   Biology and life sciences   Blood   Blood plasma   Body fluids   Carbohydrates   Cell biology   Cell signaling   Chemical compounds   Chemistry   Diabetic endocrinology   Digestive system   Disaccharides   Endocrinology   Gastrointestinal tract   Glucose   Glucose signaling   Hematology   Hormones   Insulin   Lactose   Medicine and health sciences   Milk   Monosaccharides   Organic chemistry   Organic compounds   Physical sciences   Physiology   Research Article   Signal transduction   Stomach  

摘要： To support decision-making around diet selection choices to manage glycemia following a meal, a novel mechanistic model of intermittent gastric emptying and plasma glucose-insulin dynamics was developed. Model development was guided by postprandial timecourses of plasma glucose, insulin and the gastric emptying marker acetaminophen in infant calves fed meals of 2 or 4 L milk replacer. Assigning a fast, slow or zero first-order gastric emptying rate to each interval between plasma samples fit acetaminophen curves with prediction errors equal to 9% of the mean observed acetaminophen concentration. Those gastric emptying parameters were applied to glucose appearance in conjunction with minimal models of glucose disposal and insulin dynamics to describe postprandial glycemia and insulinemia. The final model contains 20 parameters, 8 of which can be obtained by direct measurement and 12 by fitting to observations. The minimal model of intestinal glucose delivery contains 2 gastric emptying parameters and a third parameter describing the time lag between emptying and appearance of glucose in plasma. Sensitivity analysis of the aggregate model revealed that gastric emptying rate influences area under the plasma insulin curve but has little effect on area under the plasma glucose curve. This result indicates that pancreatic responsiveness is influenced by gastric emptying rate as a consequence of the quasi-exponential relationship between plasma glucose concentration and pancreatic insulin release. The fitted aggregate model was able to reproduce the multiple postprandial rises and falls in plasma glucose concentration observed in calves consuming a normal-sized meal containing milk components.

关键词： 工科院校   来华留学学位研究生   规模扩大  

摘要： 在国家"一带一路"新的战略合作发展背景下,工科院校扩大来华留学学位研究生规模迎来了新的发展机遇。文章结合上海交通大学机械与动力工程学院2011年-2014年学位留学研究生的招生实践和案例分析,从对接国家重大发展战略、专业建设、制度建设和软环境建设多方面探讨工科院校扩大来华留学研究生学位生规模的思考。

关键词： 机械臂   动力学模型   模糊滑模   PID控制  

摘要： 鉴于机械臂在机器人抓取、操作和搬运物体过程中的重要性,设计了具有五个自由度的机械臂,建立了机械臂的运动学模型,利用拉格朗日动力学建模方法建立了机械臂的动力学模型。在此基础上,设计了模糊滑模控制器,并将采用模糊滑模控制器得到的机械臂运动控制仿真结果与PID控制器进行比较,结果表明模糊滑模控制器具有良好的控制性能。研究结果为实际机械臂的动力学研究及机械臂的运动控制提供了有价值的参考。

关键词： 机器人   机械手   动力学建模   运动规划  

摘要： 研制了一种双臂、双机械手的绝缘子串更换带电作业机器人.分解了机器人作业过程中机械臂的运动.利用拉格朗日法并结合关节电机电枢电压方程对机器人机械臂基本动作进行动力学建模,得出机械臂基本动作的统一动力学模型,计算出机械臂2的动力学方程,提出基于五次多项式插值的机械臂运动轨迹规划方法,计算出机械臂2各关节运动方程.在ADAMS环境下进行机器人机械臂动力学和运动学仿真,结果验证了动力学模型的正确性,同时各关节运动轨迹规划满足运动学要求.最后在实际线路上进行机器人带电更换绝缘子串实验,结果表明机器人机械臂各关节运动获得了较好的动态性能,验证了本文提出的五次多项式插值机械臂运动轨迹规划具有较强的工程实用性,进一步提高了机器人的作业效率和稳定性.

关键词： 机械工程   多体动力学   模型  

摘要： 在本篇文章当中,笔者首先就多体动力学模型的构建进行论述,并在此基础上,就多体系统动力学方程开展了分析,最后,笔者对多体动力学在机械工程方面的具体使用进行了阐述。作者希望谨以此文,给予从事该专业相关的技术人员带来一定的参考。