Forced harmonic response of viscoelastic sandwich beams by a reduction method

The aim of this article is to develop a reduction method to determine the forced harmonic response of viscoelastic sandwich structures at a reasonable computational cost. The numerical resolution is based on the asymptotic numerical method. This type of problem is complex, and its number of degrees of freedom is double the number of the undamped structure, leading to a high computational time. To address the problem, three reduction methods are evaluated, which differ from the projection operator. Numerical tests have been performed in the case of cantilever sandwich beams. The comparison of the results obtained by the reduction order resolution with those given by the full order resolution shows both a good agreement and a significant reduction in computational cost.     

Modulation of the interfacial electrochemistry of surfactant-functionalised polypyrrole chemical sensor systems

The redox properties of electro-polymerized polypyrrole (Ppy) doped with different surfactants were studied in acid medium. It was found out that the addition of different surfactants affect the redox properties as evidenced by diffusion coefficients and rate constants calculated from experimental data obtained from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Three different surfactants were incorporated into polypyrrole matrix to form homogeneous composites i.e. anionic surfactant polyvinylsulphonic acid (PVSA) as well as non-ionic surfactants (polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (Triton-X 100) and polyoxyethylene (20) sorbitan monolaurate (Tween 20). CV and EIS experiments were carried in the presence of the redox probe K₃[Fe(CN)₆]. Diffusion coefficient was interpreted as a measure of electron movement within the composite polymer structure and rate constant was interpreted as a measure of the rate of oxidation and reduction of the redox probe. The highest value for diffusion coefficient and rate constant was obtained for Ppy/PVSA as 8.16 × 10⁻¹² cm² s⁻¹ and 1.05 × 10⁻⁵ cm s⁻¹ respectively. The values obtained by CV and EIS were in good agreement.     

Poly(n-butyl methacrylate) with primary amine end groups for supporting cell adhesion and proliferation of renal epithelial cells

Polymer coatings that support epithelial cell culture have been developed. Ozonolysis and subsequent workup of poly(butyl methacrylate-co-butadiene) copolymers is used to form oligomers with carboxylic acid end groups, which are then further reacted with diamines to provide poly(butyl methacrylate)s with primary amine end groups. The polymers are cast as films and used as cell culture substrates for human dermal fibroblasts and human renal epithelial cells. Fibroblast and epithelial cells adhere and proliferate on acid functional materials but on amine functional films epithelial cells show greater viability than fibroblasts.     

Docking Studies on Binding Modes between the CatechoI-O-Methyltransferase and Catechol Derivatives for Antiparkinson Drug

Inhibition of the enzyme COMT （catechol-O-methyltransferase） is an important approach in the treatment of Parkinson＇s disease. A series of potent catechols for COMT may give insight to develop new ways of antiparkinson drug. COMT inhibitors represent a new class of antiparkinson drugs, when they are coadministered with levodopa. Our goal of research is to study the inhibition of catechol-O-methyltransferase by molecular modeling methods. Different molecular modeling tools are used to perform this work （molecular mechanics, molecular dynamics and molecular docking （molegro virtnaldocker））. The results obtained from this work, into which the inhibition of catechol-O-methyltransferase by molecular modeling methods was elucidated, allow us to conclude that different catechols presents a more optimised inhibition of catechol-O-methyltransferase. The results suggest reducing the severity of Parkinson＇s disease.     

Numerical study of a bubble plume generated by bubble entrainment from an impinging jet

The current paper presents the prediction results of a bubbly flow under plunging jet conditions using multiphase mono- and poly-dispersed approaches. The models consider interfacial momentum transfer terms arising from drag, lift, and turbulent dispersion force for the different bubble sizes. The turbulence is modeled by an extended k–? model which accounts for bubble induced turbulence. Furthermore in case of a poly-dispersed air–water flow the bubble size distribution, bubble break-up and coalescence processes as well as different gas velocities in dependency on the bubble diameter are taken into account using the Inhomogeneous MUSIG model. This model is a generalized inhomogeneous multiple size group model based on the Eulerian modeling framework which was developed in the framework of a cooperative work between ANSYS-CFX and Forschungszentrum Dresden-Rossendorf (FZD). The latter is now implemented into the CFD code CFX.According to the correlation on the lateral lift force obtained by Tomiyama (1998); this force changes its sign in dependence on the bubble size. Consequently the entrained small bubbles are trapped below the jet. They can escape from the bubble plume only by turbulent fluctuations or by coalescence. If the size of the bubbles generated by coalescence exceeds the size at which the lift force changes its sign these large bubbles go out from the plume and rise to the surface.A turbulent model based on an additional source term for turbulence kinetic energy and turbulence eddy dissipation equation is compared to the common concept for modeling the turbulence quantities proposed by Sato et al. (1981). It has been found that the large bubble distribution is slightly affected by the turbulence modeling which affects particularly the bubble coalescence and break-up process.     

Phylogenetic and Expression Analysis of Fos Transcription Factors in Zebrafish

Members of the FOS protein family regulate gene expression responses to a multitude of extracellular signals and are dysregulated in several pathological states. Whilst mouse genetic models have provided key insights into the tissue-specific functions of these proteins in vivo, little is known about their roles during early vertebrate embryonic development. This study examined the potential of using zebrafish as a model for such studies and, more broadly, for investigating the mechanisms regulating the functions of Fos proteins in vivo. Through phylogenetic and sequence analysis, we identified six zebrafish FOS orthologues, fosaa, fosab, fosb, fosl1a, fosl1b, and fosl2, which show high conservation in key regulatory domains and post-translational modification sites compared to their equivalent human proteins. During embryogenesis, zebrafish fos genes exhibit both overlapping and distinct spatiotemporal patterns of expression in specific cell types and tissues. Most fos genes are also expressed in a variety of adult zebrafish tissues. As in humans, we also found that expression of zebrafish FOS orthologs is induced by oncogenic BRAF-ERK signalling in zebrafish melanomas. These findings suggest that zebrafish represent an alternate model to mice for investigating the regulation and functions of Fos proteins in vertebrate embryonic and adult tissues, and cancer.     

Anthropogenic disturbance of aquatic biodiversity and water quality of an urban river in Penang,Malaysia

Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water. Healthy aquatic ecosystems are supported by physicochemical properties and biological diversity. This study evaluated the anthropogenic impacts on aquatic biodiversity, especially plankton, fish, and macrobenthos, as well as the water quality of the Juru River in the Penang area. Aquatic biodiversity and river water parameters were collected from ten sampling stations along the Juru River. Seven variables were used to assess the physicochemical environment: pH, temperature, total suspended solids (TSS), salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand. At each sampling station, the total number of plankton, fish, and macrobenthic taxa were counted and analyzed. The relationships between the physicochemical parameters and aquatic biodiversity were investigated with biotypological analysis, principal component analysis, hierarchical cluster analysis, and linear regression analysis. These analyses showed that the richness and diversity indices were generally influenced by salinity, temperature, TSS, BOD, and pH. The data obtained in this study supported the bioindicator concept. The findings, as they related to scientifically informed conservation, could serve as a model for Juru River management, as well as for river management throughout Malaysia and other tropical Asian countries.     

A Preliminary Study on Ultraviolet Radiation–Cured Biofiber Composites from Oil Palm Empty Fruit Bunch

Biofiber composites, cured by ultraviolet (UV) radiation were produced using pulp made from empty fruit bunch (EFB) as the reinforcing agent and unsaturated polyester as the matrix. The EFB fibers were treated with sodium hydroxide (NaOH) solutions. The kappa number of the EFB decreased as the NaOH concentration increased. The flexural and tensile strength of the composites made from 22% NaOH-treated EFB increased as the percentage of EFB increased. Composites with 28% NaOH treated EFB had lower strength as the percentage of EFB increased. Generally, those with EFB fibers treated with 22% 15 NaOH displayed higher flexural, tensile, and impact strength and tensile modulus than those with 28% NaOH-treated fibers. No significant difference was observed for both types of composite with respect to flexural modulus and elongation at break.