Facile Chemical Synthesis and Characterization of Copper Tungstate Nanoparticles

Copper tungstate nanoparticles were synthesized by a chemical precipitation reaction in aqueous ambient involving direct addition of copper ion solution to the solution of tungstate reagent. Optimization of the synthesis procedure was carried out using Taguchi robust design as a statistical method. In order to controllable, simple and fast synthesis of copper tungstate nanoparticles, effects of some synthesis conditions such as reagents concentrations (i.e., copper and tungstate ions), flow rate of copper feeding and temperature of the reactor on the particle size of synthesized copper tungstate were investigated by the aid of an orthogonal array. The results of optimization process showed that copper tungstate nanoparticles could be prepared by controlling the effective parameters and at optimum conditions of synthesis procedure, the size of prepared copper tungstate particles was about 56 nm. Chemical composition and microstructure of the prepared copper tungstate nanoparticles were characterized by means of X-ray diffraction, scanning electron microscopy, UV–Vis spectrophotometry, FT-IR spectroscopy and Photoluminescence.     

A novel countermeasure technique to protect WSN against denial-of-sleep attacks using firefly and Hopfield neural network (HNN) algorithms

The Journal of Supercomputing - Wireless sensor networks (WSNs) contain numerous nodes that their main goals are to monitor and control environments. Also, sensor nodes distribute based on network...     

Study of the cure characteristics and viscoelastic behavior of styrene‐butadiene rubber compounds by using a rubber process analyzer

Viscoelastic and cure properties of styrene‐butadiene rubber compounds were investigated by using a “Rubber Process Analyzer.” The effects of sulfur content in the cure system and carbon black (CB) type and concentration on the cure behavior of samples were studied. As the ratio of S/accelerator in the curative increased, the cure rate increased, and the cure time decreased. Here, the elasticity was analyzed by considering the drop in the maximum of viscous torque (D_S″) and the resilience, which increased for the cure systems in the order of conventional < semiefficient < efficient. Compounds with the higher loading and fine particle size of CB had the greater cure torque values, higher vulcanization rates, and the lower cure times. With increasing CB content and CB specific surface area, D_S″ diminished, hence the elasticity. The Payne effect was observed in all strain‐sweep curves. At higher level and surface area of CB, the linear viscoelastic region disappeared, and the strain dependency of G′ was more pronounced. For higher loading and smaller particle size of CB, the relaxation modulus declined rather abruptly, and relaxation time increased. These observations signified more viscous and less elastic responses in these samples. Viscoelastic properties of compounds were explained by considering the hydrodynamic and dilution effects. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Multi‐Objective Optimization of a Cross‐Flow Plate Heat Exchanger Using Entropy Generation Minimization

Multi‐objective optimization of a cross‐flow plate fin heat exchanger (PFHE) by means of an entropy generation minimization technique is described. Entropy generation in the PFHE was separated into thermal and pressure entropy generation as two objective functions to be minimized simultaneously. The Pareto optimal frontier was obtained and a final optimal solution was selected. By implementing a decision‐making method, here the LINMAP method, the best trade‐off was achieved between thermal efficiency and pumping cost. This approach led to a configuration of the PFHE with lower magnitude of entropy generation, reduced pressure drop and pumping power, and lower operating and total cost in comparison to single‐objective optimization approaches.     

Generation and Characterization of a Zebrafish IL-2Rγc SCID Model

The IL-2 family of cytokines act via receptor complexes that share the interleukin-2 receptor gamma common (IL-2Rγc) chain to play key roles in lymphopoiesis. Inactivating IL-2Rγc mutations results in severe combined immunodeficiency (SCID) in humans and other species. This study sought to generate an equivalent zebrafish SCID model. The zebrafish il2rga gene was targeted for genome editing using TALENs and presumed loss-of-function alleles analyzed with respect to immune cell development and impacts on intestinal microbiota and tumor immunity. Knockout of zebrafish Il-2rγc.a resulted in a SCID phenotype, including a significant reduction in T cells, with NK cells also impacted. This resulted in dysregulated intestinal microbiota and defective immunity to tumor xenotransplants. Collectively, this establishes a useful zebrafish SCID model.     

Evaluation of a novel surface acoustic wave gyroscope

A novel type of gyroscope sensor using metal dot arrays on the surface of a surface acoustic wave (SAW) device has recently been independently proposed. In this paper, we report experimental trials of several devices fabricated to evaluate the effects described and also an order-of-magnitude estimate of the sensitivity to be expected. The conclusions are that this device is extremely insensitive as currently proposed     

Open- and closed-loop multiobjective optimal strategies for HIV therapy using NSGA-II

In this paper, multiobjective open- and closed-loop optimal treatment strategies for HIV/AIDS are presented. It is assumed that highly active antiretroviral therapy is available for treatment of HIV infection. Amount of drug usage and the quality of treatment are defined as two objectives of a biobjective optimization problem, and Nondominated Sorting Genetic Algorithm II is used to solve this problem. Open- and closed-loop control strategies are used to produce optimal control inputs, and the Pareto frontiers obtained from these two strategies are compared. Pareto frontier, resulted from the optimization process, suggests a set of treatment strategies, which all are optimal from a perspective, and can be used in different medical and economic conditions. Robustness of closed-loop system in the presence of measurement noises is analyzed, assuming various levels of noise.     

PARAFAC study of bovine serum albumin conformational changes in the interaction with nanosized manganese oxide as a biomimetic model for water-oxidizing complex

Water splitting toward hydrogen production is an important step and a bottleneck for large-scale energy storage in artificial photosynthesis. The effect of metal oxide nanoparticles on the biopolymers behavior and their properties is important in designing new catalysts for water-splitting reaction. Herein, the interaction of bovine serum albumin (BSA) and MnO_x nanoclusters is studied for the first time, exploiting the intrinsic excitation-emission (EEM) fluorescence of tryptophan and tyrosine residues. As the conformation of BSA changes as a function of pH and temperatures, three-way fluorescence data were recorded for BSA and BSA/MnO_x. Then, the obtained profiles from parallel factor analysis (PARAFAC) were interpreted. Generally, the results from fluorescence spectroscopy showed that the MnO_x nanoparticles cause some changes in the structure of BSA conformation as a function of pH and temperature. Also, the denaturation pathway of the BSA molecule is significantly different in the presence of MnO_x nanoclusters. Moreover, the same result is acquired by augmentation of pH and temperature data for BSA and BSA/MnO_x, which confirms that the fluorescence changes due to considered components during the processes. Although the EEM fluorescence spectra of similar proteins are almost identical, the cube of spectra measured during their conformational changes can be significantly different and applicable in rapid and low cost investigation of proteins. Spectral change and selectivity for similar proteins can be achieved without labeling with fluorophore molecules.