Swelling effect of a polymer electrolyte membrane on the development of a semi-empirical cell voltage model

We developed a new cell voltage model which depends on the current density response of the proton exchange membrane fuel cell (PEMFC). The proposed model focuses on the conductivity of a PEMFC fuel cell. The model for conductivity of a polymer electrolyte membrane, Nafion, uses the thermodynamic function to represent water activity. We observed membrane conductivity by monitoring the chemical potential of the swelling of the hydrogel. The swelling equilibrium of the ionized hydrogel is governed by the free energy of mixing, the free energy of elasticity, and the concentration of counterions with fixed charges on the gel network. A cell voltage equation with reasonable boundary conditions, including the swelling effect, which plays a major role in determining the cell voltage of a PEMFC, was newly developed.     

Membrane Surface Nanostructures and Adhesion Property of T Lymphocytes Exploited by AFM

The activation of T lymphocytes plays a very important role in T-cell-mediated immune response. Though there are many related literatures, the changes of membrane surface nanostructures and adhesion property of T lymphocytes at different activation stages have not been reported yet. However, these investigations will help us further understand the biophysical and immunologic function of T lymphocytes in the context of activation. In the present study, the membrane architectures of peripheral blood T lymphocytes were obtained by AFM, and adhesion force of the cell membrane were measured by acquiring force–distance curves. The results indicated that the cell volume increased with the increases of activation time, whereas membrane surface adhesion force decreased, even though the local stiffness for resting and activated cells is similar. The results provided complementary and important data to further understand the variation of biophysical properties of T lymphocytes in the context of in vitro activation.     

Influence of ionic liquids on the growth ofEscherichia coli

Ionic liquids are compounds that composed only of ions and are liquid at room temperature. Thus, it is normally named room temperature ionic liquid (RTIL). In this study, the application of RTILs to the extractive fermentation of biomaterials was investigated as a substitute of organic solvents. The relative toxicity of the RTILs on the growth ofE. coli was tested. The inhibition of cell growth in the presence of various ionic liquids was measured using solid and liquid culture, and EC₅₀ of each RTILs was calculated. The number of viable and total cells was measured by the number of colonies and optical density, respectively. Effective concentrations of toxicity (EC₅₀) in these tested systems were similar with conventional solvents, such as acetone, acetonitrile, and ethanol. The viability ofE. coli was affected by the polarity and ionic properties of ionic liquids. The resistance of the microorganisms against ionic liquids was different with the cations and anions composing ionic liquids. No general influence of the anionic compound of the ionic liquids was found on toxicity comparing with distinctive influence of cationic moiety.     

Inhibitory Effects of Cholesterol Derivatives on DNA Polymerase and Topoisomerase Activities, and Human Cancer Cell Growth

This paper describes the inhibitory activities of cholesterol derivatives such as cholesterol, sodium cholesteryl sulfate, cholesteryl-5α, 6α-epoxide, cholesteryl chloride, cholesteryl bromide, and cholesteryl hemisuccinate (compounds 1–6, respectively) against DNA polymerase (pol), DNA topoisomerase (topo), and human cancer cell growth. Among the compounds tested, compounds 2 and 6 revealed themselves to be potent inhibitors of animal pols, and the IC₅₀ values for pols were 0.84–11.6 and 2.9–148 μM, respectively. Compounds 2, 3 and 6 inhibited the activity of human topo II, with IC₅₀ values of 5.0, 12.5 and 120 μM, respectively. Compounds 2, 3 and 6 also suppressed human cancer cell (promyelocytic leukemia cell line, HL-60) growth, and LD₅₀ values were 8.8, 20.2 and 72.3 μM, respectively, suggesting that cell growth inhibition had the same tendency as the inhibition of topos rather than pols. Compounds 2 and 6 arrested the cells in S and G2/M phases, compound 3 arrested the cells in the G2/M phase, and these compounds also increased sub-G1 phase in the cell cycle. These results suggested that the effect of cell cycle arrest might be effective on both pols and topos activities. From these findings, the action mode of cholesterol derivatives as anti-cancer compounds is discussed.     

巧用CL-02DS中文设定显示单元

本文介绍了利用CL－02DS中文设定显示单元，配合程序设计，使之实现记录功能。     

PEMFC燃料电池三级电堆的装配分析

以提高PEMFC燃料电池电堆性能为目的,研究了电堆组装过程中加载方式和载荷对电堆接触电阻及电堆性能的影响。利用有限元分析软件ANSYS Workbench对三级电堆的装配过程进行有限元分析。分析了几种不同大小的载荷及不同的加载方式的装配对电堆性能的影响,对比了这几种情况下燃料电池堆的核心部件膜电极(MEA)组件的变形情况及应力分布情况,得出电堆的最佳装配载荷。该结果可为燃料电池电堆的装配提供较好的参考依据。     

Review of free software tools for image analysis of fluorescence cell micrographs

An increasing number of free software tools have been made available for the evaluation of fluorescence cell micrographs. The main users are biologists and related life scientists with no or little knowledge of image processing. In this review, we give an overview of available tools and guidelines about which tools the users should use to segment fluorescence micrographs. We selected 15 free tools and divided them into stand‐alone, Matlab‐based, ImageJ‐based, free demo versions of commercial tools and data sharing tools. The review consists of two parts: First, we developed a criteria catalogue and rated the tools regarding structural requirements, functionality (flexibility, segmentation and image processing filters) and usability (documentation, data management, usability and visualization). Second, we performed an image processing case study with four representative fluorescence micrograph segmentation tasks with figure‐ground and cell separation. The tools display a wide range of functionality and usability. In the image processing case study, we were able to perform figure‐ground separation in all micrographs using mainly thresholding. Cell separation was not possible with most of the tools, because cell separation methods are provided only by a subset of the tools and are difficult to parametrize and to use. Most important is that the usability matches the functionality of a tool. To be usable, specialized tools with less functionality need to fulfill less usability criteria, whereas multipurpose tools need a well‐structured menu and intuitive graphical user interface.     

有机物燃料电池

有机物直接作为燃料电池的燃料,在工艺上可以省去氢气制造与精制的过程,另外由于气体燃料改为液体燃料大大缩小了电池体积,有利于实用化,目前英、法、德等国正在研制20KW直接型甲醇燃料电池,可以借鉴。     

Pathogen-induced Release of Plant Allomone Manipulates Vector Insect Behavior

Infochemicals mediate communication within and between different trophic levels. In this study, we identified a new type of plant allomone induced by a plant pathogen and perceived by its vector insect Cacopsylla picta. This phloem-feeding psyllid is the main vector of Candidatus Phytoplasma mali, a cell wall-lacking bacterium that causes the so-called apple proliferation disease. In a previous study, we showed that newly emerged females of C. picta were attracted by the odor of phytoplasma-infected apple plants (Malus domestica), which release ß-caryophyllene in contrast to uninfected plants. Here, the attractiveness of this sesquiterpene for C. picta was confirmed in both olfactometer bioassays and field studies. Synthetic ß-caryophyllene was highly attractive to newly emerged adults of C. picta both when offered simultaneously with healthy apple odor and without. The psyllid’s response was independent of its odor experience and infection status. These results confirm our previously established hypothesis that this phytoplasma manipulates the behavior of its vector insect by changing the odor blend of its host plant. Deployed in apple orchards, sticky traps baited with ß-caryophyllene dispensers caught both males and females of C. picta. Consequently, this new type of infochemical, i.e., a phytopathogen-induced plant allomone, represents a promising compound to develop innovative techniques for monitoring or maybe even mass trapping of C. picta.