CHESDA: continuous hybrid and energy-efficient secure data aggregation for WSN

The Journal of Supercomputing - Data aggregation is an effective mechanism to prolong lifetime in the wireless sensor networks by preventing extra data transmission. However, it may have some...     

Plasticized poly(vinyl chloride) composites: Influence of different nanofillers as antimigration agents

In this study, plasticized poly(vinyl chloride) (PVC) composites with different nanofillers, including single‐walled carbon nanotubes (SWCNTs), organoclay, TiO₂, and ZnO nanoparticles, were prepared, and their effects on plasticizer migration were investigated. Scanning electron micrographs revealed the dispersion quality of the nanofillers in the polymer matrix. It had a significant influence on the performance of the nanofillers in the process of plasticizer migration. Migration and exudation tests showed that the nanofillers could efficiently hinder plasticizer migration. On the basis of these results, we concluded that carbon nanotubes were the best antimigration agent in the plasticized system. This was ascribed to the high aspect ratio of the SWCNTs and the good interactions between them and the plasticizer. Also, TiO₂ nanoparticles showed a better performance compared to the ZnO nanoparticles. This was due to the more homogeneous dispersion of the TiO₂ in the polymer matrix and the higher surface area of the particles. The differential scanning calorimetry thermograms were in good agreement with the migration tests. The lowest change in the glass‐transition temperature was observed for the composite filled with SWCNTs. This indicated that a lower amount of the plasticizer migrated from PVC. The thermogravimetric analysis curves showed that the incorporation of the nanofillers improved the thermal stability of the PVC. The results could be useful for determining the efficiency of plasticized PVC in applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42559.     

Determination of aflatoxins B1 and B2 by adsorptive cathodic stripping voltammetry in groundnut

In this study, adsorptive stripping voltammetry was proposed for determination of aflatoxins B1 (AFB1) and B2 (AFB2) using hanging mercury drop electrode (HMDE) as the working electrode. Both aflatoxins were found to adsorb and undergo irreversible reduction reaction at the working mercury electrode. The experimental conditions were optimised by one-at-a time and experimental design to obtain the best characterised peak in terms of peak height with analytical validation of the method for each aflatoxin. The calibration curves for aflatoxins AFB1 and AFB2 were linear in the ranges of 0.4–40 ng ml⁻¹ and 0.2–70 ng ml⁻¹ with the limit of detections (LOD) 0.15 and 0.10 ng ml⁻¹, respectively. The proposed method was applied for the analysis of aflatoxins in groundnut samples and the results were compared with those obtained by the HPLC technique.     

Adaptive Nonlinear Direct Torque Control of Sensorless IM Drives With Efficiency Optimization

Efficiency optimization of induction motor (IM) drives is a major subject based on these drives' extensive use in the industry. Among the different proposed methods, a model-based approach (MBA) seems to be the fast one. However, this method needs the motor parameters that must be correctly identified. On the other hand, a search-based approach (SBA) is a parameter-independent method but needs a greater convergence time. In this paper, a novel model-based loss-minimization approach is presented, which is combined with a backstepping direct torque control of the IM drive. An improved search-based method for efficiency optimization is also introduced. The proposed controller is realized in the stationary reference frame and has a fast-tracking capability of rotor flux and electromagnetic torque. Moreover, a sliding-mode rotor-flux observer is introduced, which is employed for simultaneous determination of rotor-flux space vector, rotor speed, and rotor time constant. The proposed control idea is experimentally implemented in real time using a field-programmable gate-array board synchronized with a personal computer. Simulation and experimental results are finally presented to verify the effectiveness of the method proposed.      

Adenovirus-mediated p53 gene therapy and paclitaxel have synergistic efficacy in models of human head and neck, ovarian, prostate, and breast cancer

Synergy (or antagonism) between two chemical agents is an in vitro empirical phenomenon, in which the observed effect of the combination is more (or less) than what would be predicted from the effects of each agent working alone. Although mathematical synergy is not directly provable in the clinical setting, it does predict a favorable outcome when the two therapeutics are combined in vivo and strongly suggests the presence of in vivo synergy. In contrast, overt antagonism warns of future problems. Sophisticated three-dimensional statistical modeling was used to evaluate the presence of synergistic, additive, or antagonistic efficacy between adenovirus (Ad)-mediated p53 gene therapy (p53 Ad) and paclitaxel (Taxol) in a panel of human tumor cell lines. Cells were either pretreated with paclitaxel 24 h before p53 Ad or treated with both agents simultaneously. Cell proliferation was measured 3 days later. Paclitaxel had synergistic or additive efficacy with p53 gene therapy. In no case was the interaction antagonistic. Cell cycle analysis demonstrated that p53 Ad arrested cells in G0/G1 prior to apoptotic cell death, whereas paclitaxel arrested cells in G2-M prior to apoptotic cell death. When combined, the relative concentration of each agent determined the dominant cellular response. These results are consistent with the previously reported cell cycle effects of p53 or paclitaxel, respectively; however, these data fail to explain the observed drug synergy. We found that low concentrations of paclitaxel (1-14 nM) increased the number of cells transduced by recombinant Ad 3-35% in a dose-dependent manner, which is one possible mechanism for the observed synergy. Of particular note, the concentrations of paclitaxel responsible for increased Ad transduction were lower than the concentrations required for microtubule condensation. The efficacy of combination therapy was also evaluated in vivo. In the p53null SK-OV-3 xenograft model of ovarian cancer, a dosing schedule of p53 Ad that, by itself, had a relatively minimal effect on tumor burden (16%) caused a much greater decrease in tumor burden (55%) when combined with paclitaxel. Greater combined efficacy was also observed in the p53mut DU-145 prostate, p53mut MDA-MB-468 breast, and p53mut MDA-MB-231 breast cancer xenograft models in vivo. In summary, p53 Ad for cancer shows enhanced efficacy when combined with paclitaxel. This combination is recommended for clinical cancer trials.     

Model predictive control optimisation using the metaheuristic optimisation for blood pressure control

Given the importance of high blood pressure, it is important to control and maintain a constant blood pressure level in the normal state. The main aim of this article is to design a model predictive controller with a genetic algorithm (GA) for the regulation of arterial blood pressure. The present study is an applied cross‐sectional study. In order to do this research, studies related to designing mathematical models for blood pressure regulation and mechanical models for heart muscle and pressure sensors are investigated. Then, a model predictive controller with GA is designed for blood pressure control. All control and design operations are performed in the MATLAB software. According to the viscoelasticity of blood, transducer, and injection set, we can assume the mechanical model as Mass, Spring, and Damper. Initially, the patient''s blood pressure is lower than normal, and after controlling, the patient''s blood pressure returned to normal. By using a GA‐based model predictive control (MPC), mathematical validation, and mechanical model, the patient''s blood pressure can be adjusted and maintained. The simulation result shows that the GA‐based MPC offers acceptable response and speed of operation and the proposed controller can achieve good tracking and disturbance rejection.     

Design of a wideband miniature dielectric-filled waveguide antennafor collision-avoidance radar

This article presents a theoretical and experimental study of the design of a miniaturized wideband dielectric-filled waveguide (DFW) antenna. The operational frequency is X band, i.e., 9.0⩽f⩽10.5 GHz. The desired bandwidth is 1.5 GHz. The antenna uses an air-gap matching network to reduce its high aperture reflection. In order to ease the integration with antenna circuits and to increase the bandwidth, two E-plane steps are used. The antenna is designed to have -3 dB beamwidths of 60° and 100° for the E- and H-plane patterns, respectively. An input reflection of less than -10 dB for the desired bandwidth is observed. The gain of the antenna is 7 dBi. A cross-polar level of less than -25 dB is achieved. This article discusses the mathematical model for input reflection, the design scenarios, and the experimental results     

Identification of the mechanical impedance at the human finger tip

The present study evaluates the potential of smokeless tobacco to modify the chemopreventive efficacy of minor dietary constituents, including garlic, mace or black mustard, via modulating the competing pathways of hepatic detoxication system and antioxidant defense mechanism in murine system. Garlic (100 mg/kg b.w. per day) by gavage and mace (1% w/w) or black mustard (1% w/w) in diet induced a significant increase in the levels of glutathione-S-transferase (GST), acid-soluble sulfhydryl (-SH), cytochrome b5 (Cyt.b5) and cytochrome P-450 (Cyt.P-450) in murine liver. The hepatic levels of GST and -SH were significantly depressed whereas microsomal Cyt.b5, Cyt.P-450 and MDA levels were elevated in groups treated with smokeless tobacco (50 or 100 mg/kg b.w. per day). The data revealed the inhibitory potential of smokeless tobacco on garlic-induced hepatic GST/GSH system besides the significant augmentation by smokeless tobacco on garlic or mace or black mustard-induced microsomal cytochromes. The possible implications of modulation in competing bioactivation and detoxication pathways in the process of chemical carcinogenesis are discussed.     

Local oscillator radiation from active integrated antennas

Active receiving antennas with an integrated filter, amplifier, mixer and local oscillator have significant radiation at the local oscillator frequency. This radiation may be out of band and could be a problem in cluttered environments. In this Letter, the problem is evaluated through measurements and simulation on integrated microstrip patch antennas