Hydrodynamic Permeability of the Membrane as a System of Rigid Particles Covered with Porous Layer (Cell Model)

Problem of uniform flow of viscous, incompressible liquid around a rigid particle covered with porous layer and located inside the spherical cell was solved at small Reynolds numbers. In order to describe the motion of liquid within porous layer, the Brinkman equations were used. Based on the Happel and Brenner cell method, the hydrodynamic permeability of the membrane consisting of the system of porous particles with rigid impermeable cores was calculated.     

A Biomimetic Approach for Spatially Controlled Cell Membrane Engineering Using Fusogenic Spherical Nucleic Acid

Engineering of the cell plasma membrane using functional DNA is important for studying and controlling cellular behaviors. However, most efforts to apply artificial DNA interactions on cells are limited to external membrane surface due to the lack of suitable synthetic tools to engineer the intracellular side, which impedes many applications in cell biology. Inspired by the natural extracellular vesicle-cell fusion process, we have developed a fusogenic spherical nucleic acid construct to realize robust DNA functionalization on both external and internal cell surfaces via liposome fusion-based transport (LiFT) strategy, which enables applications including the construction of heterotypic cell assembly for programmed signaling pathway and detection of intracellular metabolites. This approach can engineer cell membranes in a highly efficient and spatially controlled manner, allowing one to build anisotropic membrane structures with two orthogonal DNA functionalities.     

Viscosity Detection with a Pulseless PUMP for Liquid Chromatography

Abstract

The performance of a differential pressure transducer as a viscosity detector in conjunction with a pulseless high pressure syringe pump designed for the purpose is described. The detector, although relatively insensitive, is inexpensive and extremely rugged. Because it is non-destructive and introduces very little dispersion, serial coupling ahead of other detectors is possible. Response behavior is demonstrated.     

细胞膜离子通道的一个非线性动力学模型

提出一个关于细胞膜离子通道的非线性动力学模型，此模型克服了Liebovitch模型的一些严重缺陷，也更符合通道中离子运动实际．模型导出的Ⅰ-Ⅴ曲线与实验结果符合得很好．     

A Model of Solid-Phase Synthesis in Binary Powder Mixtures with Allowance for Caking

Russian Journal of Physical Chemistry A - A mathematical model of solid-phase chemical synthesis in a binary powder mixture is constructed and studied with allowance for the shrinking of the...     

Hollow Polydimethylsiloxane Beads with a Porous Structure for Cell Encapsulation

Based on a water‐in‐oil‐in‐water emulsion system, porous and hollow polydimethylsiloxane (PDMS) beads containing cells using a simple fluidic device with three flow channels are fabricated. Poly(ethylene glycol) (PEG) in the PDMS oil phase is served as a porogen for pore development. The feasibility of the porous PDMS beads prepared with different PEG concentrations (10, 20, and 30 wt%) for cell encapsulation in terms of pore size, protein diffusion, and cell proliferation inside the PDMS beads is evaluated. The PDMS beads prepared with PEG 30 wt% are exhibited a highly porous structure and facilitated fast diffusion of protein from the core domain to the outer phase, eventually leading to enhanced cell proliferation. The results clearly indicate that hollow PDMS beads with a porous structure could provide a favorable microenvironment for cell survival due to the large porous structure.

     

质子交换膜燃料电池模型研究进展

综述了质子交换膜燃料电池 (PEMFC)数学模型的研究进展 ,分析PEMFC中膜、催化层、扩散层和流场区域的传递现象和水、热管理的重要性 ,讨论了模型的维数、复杂性和求解方法 .提出了带有时间维数的PEMFC模型研究的实际应用意义     

Determination of Pharmaceuticals by Dynamic Cell Membrane Chromatography Coupled with High-Performance Liquid Chromatography

As a biological affinity chromatographic method, cell membrane chromatography (CMC) using a silica stationary phase covered with specific cell membrane has been used in screening active components. The innovation of this work is that the bioactive cell membrane and the chromatographic packing are mixed and absorbed for the first time to form the pre-column. The pre-column was placed in front of a C₁₈ column to create dynamic CMC online high-performance liquid chromatography (HPLC) system. The retention behavior and dynamic changes of pharmaceuticals were studied for this system. The results indicate that the retention time of the drug was increased and the symmetry factor reached the analytical level after the addition of the dynamic cell membrane pre-column. Therefore, the dynamic CMC coupled with HPLC system may be a potentially rapid and efficient drug analysis approach for the interaction of drug molecule and receptor on red blood cell membranes.     

A New Spherical Hydroxyapatite for High Performance Liquid Chromatography of Proteins

Abstract

Basic properties of a newly developed hydroxyapatite column and results of its application to the separation of proteins are described. The hydroxyapatite was completely spherical and porous beads in appearance by scanning electron microscopy, and showed superior properties to other types of hydroxyapatite column. The column was mechanically strong enough to show the pressure limit of 140–150 kg/cm². The hydroxyapatite column showed excellent mechanical and chemical stability, and was applicable to high speed and high resolution separation of proteins. Proteins are recovered in high yield after the chromatography.     

Theory of the Filtration of Nonelectrolyte Solutions through a Biporous Membrane with Allowance for the Kinetics of Pore Blocking

The quasi-steady-state model describing ultra- and microfiltration through infinite membranes with allowance for pore blocking is proposed; it can be assumed in the first approximation that the membrane structure is biporous.     

A Cell Model of an Ion-Exchange Membrane. Capillary-Osmosis and Reverse-Osmosis Coefficients

Colloid Journal - The capillary-osmosis and reverse-osmosis coefficients of an ion-exchange membrane have been calculated as the kinetic coefficients of the Onsager matrix within the thermodynamics...     

消除夹带溶胀的新液膜操作法

消除夹带溶胀的新液膜操作法曹汉瑾，褚莹，何彦涛，吴子生，严忠（东北师范大学化学系长春１３００２４）关键词液膜，油／水乳液，溶胀，夹带，包裹消除液膜操作中的夹带溶胀对液膜的工业化具有重要意义，夹带溶胀分为包裹溶胀和再液化溶胀。前者是乳状液滴上浮时将水相...     

TiO2微粒功能化多孔Al2O3膜的光电化学研究

用恒电位法制备了多孔Al2O3薄膜,通过在Al2O3薄膜孔内水蒸汽水解钛酸异丙酯生成了锐钛矿型TiO2微粒,制备出了Al2O3与TiO2微粒的复合薄膜．用XRD,SEM,光电化学方法进行了研究．实验表明：该复合薄膜具有光电转换特性,在光催化、光电化学太阳能转换中具有应用价值．     

Efficiency of Three-Layered Porous Electrodes with Variable Conductance or Variable Specific Areas of Layers: A Comparative Analysis

Efficiency of action of variable conductance and specific area of porous matrix on the current distribution is compared in identical conditions with the aid of numerical calculations based on a one-dimensional model for a porous electrode. Versions of three-layered flow-through porous electrodes with different and identical parameters are considered at different reactant conversion degrees.     

A Cell Model of an Ion-Exchange Membrane. Electrodiffusion Coefficient and Diffusion Permeability

Colloid Journal - Electrodiffusion coefficient and diffusion permeability of an ion-exchange membrane have been calculated as the kinetic coefficients of the Onsager matrix in terms of the...     

A Theory of Homogeneous Boiling-Up of Liquid Solutions: 3. Growth of Supercritical Bubbles with Allowance for Solvent Fugacity

The growth of supercritical bubbles in a liquid solution with time was determined with allowance for solvent fugacity. It was shown that the presence of solvent vapors in supercritical bubbles caused by the solvent fugacity tends to increase the growth rate of supercritical bubbles. As a result, the driving force of the growth of supercritical bubbles is not the supersaturation of dissolved gas but the calculated larger parameter that takes into account the solvent fugacity. The condition of the steady-state regime of the absorption of gas molecules by the supercritical bubbles from solution with the movable bubble boundary was studied. The maximal volume fraction of all supercritical bubbles in solution was found. The condition of mechanical equilibrium between the supercritical bubbles and the solution was studied.     

离子液体内耦合液膜迁移苯酚的研究

本文以N-甲基咪唑为原料,采用微波合成法,制备了疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6),并将其作为液膜,对苯酚的内耦合液膜迁移进行了研究,考察了温度、搅拌速度、料液相酸度、初始浓度及解析相NaOH浓度等因素对苯酚迁移的影响,得出了最佳迁移条件:温度300 K,搅拌速度350 r/min,料液相pH为3.65,解析相NaOH浓度为0.8 mol/L.在最佳液膜条件下,对于10 mg/L苯酚溶液,迁移110 min,迁移率可以达到97.3%,膜相中有少量苯酚滞留.离子液体可循环使用.     

质子交换膜燃料电池及电池组模型分析

本文对现有质子交换膜燃料电池以及电池组模型进行比较分析,认为数学模型的建立,可以增加对燃料电池及电池组内部的传递现象和反应机理的认识,同时可以预测电池以及电池组的性能,并且对优化电池结构参数具有指导意义.模型分析包括了现阶段质子交换膜燃料电池单电池模型和电池组模型的基本类别,它们是单电池CFD数值模拟模型、单电池以及电池组性能模拟模型、燃料电池组气体分配模型、系统模型和非稳态模型.比较了几种模型的建模方式及不同模型的应用范围和各自的优缺点.     

Sodium Hypochlorite Production in an Electrolyzing Cell with a Ceramic Membrane

Electrochemical synthesis of sodium hypochlorite in a membrane electrolyzing cell with OCTA and a ZrO₂-based inorganic ceramic membrane is studied. Effects of the current density, concentration of the NaCl solution, and the rate of supply of solutions into electrode chambers are investigated. Under optimum conditions, the current efficiency for sodium hypochlorite is 77%, with a specific consumption of power of 2.4 kW h kg^–1and sodium chloride, 3.1 kg kg^–1. The anode's corrosion resistance in the experimental conditions is determined.