Anti-viral activity of blue chanterelle (Polyozellus multiplex) that inhibits α-glucosidase

Blue chanterelle (Polyozellus multiplex), known as an edible mushroom, was extracted using methanol to screen on anti-viral agent. Syncytium formation in Newcastle disease virus (NDV)-infected baby hamster kidney (BHK) cell originates from the trafficking of viral glycoprotein into cell-surface. Blue chanterelle inhibited not only syncytium formation, but also trafficking of glycoprotein, hemagglutinin-neuramidase (HN), onto cell-surface. Viral glycoprotein is processed within the endoplasmic reticulum during routing to surface. Blue chanterelle extracts showed the inhibitory activities (IC₅₀ 10 μg/mL) against α-glucosidase. These results suggested that blue chanterelle extracts inhibited the cell-surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.     

Melt polymerization of bisphenol‐A and diphenyl carbonate in a semibatch reactor

The effect of thermodynamic phase equilibrium on the kinetics of semibatch melt polycondensation of bisphenol‐A and diphenyl carbonate was studied for the synthesis of polycarbonate. In the melt‐polymerization process, a partial loss of diphenyl carbonate occurs as the reaction by‐product phenol is removed from the reactor. To obtain a high molecular weight polymer under high temperature and low‐pressure conditions, a stoichiometric mol ratio of the two reactive end groups needs to be maintained during the polymerization. In this work, vapor–liquid equilibrium data for a binary mixture of phenol and diphenyl carbonate are reported and they are used in conjunction with the Wilson equation to calculate the exact amounts of diphenyl carbonate and phenol returned from a reflux column to the reactor. A good agreement between the reactor model simulations and the experimental polymerization data was obtained. It was also observed that diphenyl carbonate is quickly consumed during the early stage of polymerization and the fraction of evaporated diphenyl carbonate refluxed to the reactor is essentially constant during this period. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1253–1266, 2001     

Optimization of Ring‐Closing Metathesis: Inert Gas Sparging and Microwave Irradiation

A systematic study of a ring‐closing metathesis towards a tetrasubstituted double bond as part of a seven‐membered ring in a 5.7.5‐tricyclic guaianolide system is described. By combining two techniques, namely sparging an inert gas through the solution together with dielectric heating via microwave irradiation a high‐yielding ring‐closing metathesis reaction in this particularly challenging case was achieved. The results obtained compare favorably with conventional heating conditions or with microwave irradiation in a closed system. The key aspects seem to be that rapid microwave irradiation diminishes catalyst decay by allowing the required high reaction temperature to be reached quickly and homogeneously and thereby providing enough energy for a successful metathesis reaction, while inert gas sparging is purging off evolving ethylene to shift the equilibrium to the product.     

Improvement of electrical properties in screen-printed crystalline silicon solar cells by contact treatment of the grid edge

In this study, the influence of HF treatment of Ag pastes after a firing process was investigated. It was shown that the HF treatment can improve the fill factors and efficiencies of various cells including those with high initial specific contact resistances. SEM images showed that this improvement is due to the etching of the thin glass layer at the Ag-Si boundary, which exposes the Ag crystallites and colloids. These colloids electrically connect the bulk Ag to the Si through a direct contact, which reduces both the transfer length and the specific contact resistance. A model of the current path was proposed to explain the effect of HF treatment on the edge of the Ag grid.     

3D heterostructured architectures of Co(3)O(4) nanoparticles deposited on porous graphene surfaces for high performance of lithium ion batteries

Control of structure and morphology in electrode design is crucial for creating efficient transport pathways of ions and electrons in high-performance energy storage devices. Here we report the fabrication of high-performance anode materials for lithium-ion batteries based on a 3D heterostructured architecture consisting of Co(3)O(4) nanoparticles deposited onto porous graphene surfaces. A combination of replication and filtration processes - a simple and general method - allows a direct assembly of 2D graphene sheets into 3D porous films with large surface area, porosity, and mechanical stability. The polystyrene spheres are employed as sacrificial templates for an embossing technique that yields porous structures with tunable pore sizes ranging from 100 nm to 2 μm. Co(3)O(4) nanoparticles with high-energy storage capacity can be easily incorporated into the pore surfaces by a simple deposition strategy, thereby creating a 3D heterogeneous Co(3)O(4)/graphene film. In particular, we exploit the 3D Co(3)O(4)/graphene composite films as anode materials for lithium ion batteries in order to resolve the current issues of rate capability and cycling life. This unique heterogeneous 3D structure is capable of delivering excellent Li(+) ion storage/release and displays the following characteristics: a high rate capability of 71% retention even at a high current rate of 1000 mA g(-1) and a good cycling performance with 90.6% retention during 50 cycles. The versatile and simple nature of preparing 3D heterogeneous graphene films with various functional nanoparticles can be extended to overcome the major challenges that exist for many electrochemical devices.     

Immersed smoothed finite element method for two dimensional fluid–structure interaction problems

A novel method called immersed smoothed FEM using three‐node triangular element is proposed for two‐dimensional fluid–structure interaction (FSI) problems with largely deformable nonlinear solids placed within incompressible viscous fluid. The fluid flows are solved using the semi‐implicit characteristic‐based split method. Smoothed FEMs are employed to calculate the transient responses of solids based on explicit time integration. The fictitious fluid with two assumptions is introduced to achieve the continuous form of the FSI conditions. The discrete formulations to calculate the FSI forces are obtained in terms of the characteristic‐based split scheme, and the algorithm based on a set of fictitious fluid mesh is proposed for evaluating the FSI force exerted on the solid. The accuracy, stability, and convergence properties of immersed smoothed FEM are verified by numerical examples. Investigations on the mesh size ratio indicate that the stability is fairly independent of the wide range of the mesh size ratio. No additional volume correction is required to satisfy the incompressible constraints. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis of the assessment factors for renewable energy dissemination program evaluation using fuzzy AHP

By 2030, Korean government aims to increase the share of new and renewable energy sources to 11% in the overall primary energy mix, that is, approximately 33 million TOE. However, carefully designed program is needed given the current low level of the share (2.37%, approximately 5.6 million TOE, as of 2007). Therefore, alongside R&D on new and renewable energy technology, establishing an effective dissemination program is also essential. This would require a decision-making base, for which this study established the criteria and factors and assessed the importance of each factor using the fuzzy analytical hierarchy process (AHP) method. Five criteria – technological, market-related, economic, environmental, and policy-related – and a total of seventeen factors were established. From the weights estimation results, we derived four major conclusions regarding the importance of economic feasibility, the advancement of the target technology in the global market, the disagreement between the policy maker and the specialist group, and the application of the results.     

A note on true desingularisation of boundary integral methods for three-dimensional potential problems

A desingularized boundary element formulation for the three-dimensional potential problem will be presented. It is based on integral identities for the fundamental solution. The shown approach has the advantage that the singular terms on both influence matrices can be directly calculated by replacing it with a special summation of the other off-diagonal elements. It is an extension of the so-called 4π rule in which the strongest singularity is removed by replacing the terms of one of the influence matrices by 4π minus the sum of the off-diagonal terms of the same row. It is shown here that a similar method can also be applied to the weakest singularity, thereby completely desingularizing the method. Both integral equations and their corresponding matrix–vector notation will be presented.     

Effect of Subcritical Carbon Dioxide Extraction and Bran Stabilization Methods on Rice Bran Oil

The extraction of rice bran oil using the conventional organic solvent‐based Soxhlet method involves hazardous chemicals, whereas supercritical fluid extraction is a costly high‐temperature operating system. The subcritical carbon dioxide Soxhlet (SCDS) system, which operates at a low temperature, was evaluated for the extraction of rice bran oil in this study. In addition, rice bran that had been subjected to steam or hot‐air stabilization were compared with unstabilized rice bran (control). The yields; contents of tocopherols, tocotrienols and oryzanol; fatty acid profiles; and the oxidative stabilities of the extracted rice bran oils were analyzed. The yields using hexane and SCDS extraction were approximately 22 and 13–14.5 %, respectively. However, oil extracted using the SCDS system contained approximately 10 times more oryzanol and tocol compounds and had lower free fatty acid levels and peroxide values compared with hexane‐extracted oil. Overall, SCDS extraction of steamed rice bran represents a promising method to produce premium‐quality rice bran oil.     

Thermal analysis of heat pipe shell-fin structures with selective coatings under radiation

The purpose of this study is to investigate the thermal response of a heat pipe shell-fin structure that is selectively coated and is subject to uneven radiation from upper and lower sides. Such a structure would arise when fins are attached to opposing sides of the condenser or evaporator section of heat pipes to enhance the heat transfer performance. Typical examples include radiators for space applications and solar energy collectors for water heating. The temperature distribution in the circumferential direction of the heat pipe shell as well as that in the fin is examined via theoretical modeling and numerical analysis. The model accounts for the effects of selective coatings. Both steady-state and transient solution procedures are presented. Examination of the steady-state results justifies the use of a thermally-lumped formulation for the heat pipe shell region. The effect of fin width is investigated as a typical design variable. The fin efficiency and the collector efficiency are also presented as functions of heat pipe operating temperature and fin widith. The influence of the surface properties on the thermal performance of the heat pipe shell-fin structure are also examined.