Effect of Silane-Coupling Modification on the Performance of chitosan-poly vinyl Alcohol-Hybrid Scaffolds in Bone Tissue Engineering

Silicon - Biocompatibility and biodegradability characteristics of some polymers make them an excellent candidate to fabricate porous scaffolds for tissue engineering applications. However, the...     

Compact wide stopband lowpass filter using spiral loaded tapered compact microstrip resonator cell

A new spiral loaded tapered compact microstrip resonator cell (SPLT-CMRC) is presented. The addition of spiral stubs to the CMRC creates transmission zeroes in the stopband which extended the stopband of the ?lter. The proposed resonator is used to design a compact lowpass ?lter (LPF) with wide and high rejection in stopband. The fabricated ?lter has a 3 dB cutoff frequency at 8 GHz. The insertion loss in the passband is less than 0.2 dB from DC to 7.2 GHz. The proposed ?lter has wide stopband from 9.47 to 40 GHz with attenuation level of ?20 dB. The demonstrated filter is designed and fabricated. There is a good agreement between the measured and simulated S-parameters.     

Cloud Point-Dispersive Liquid–Liquid Microextraction for Extraction of Organic Acids from Biological Samples

A new method combining cloud point extraction (CPE) with dispersive liquid–liquid microextraction (DLLME) named “cloud point‐dispersive liquid–liquid microextraction (CP‐DLLME)” was presented in this work for the first time for the determination of organic acids as model compounds in biological samples using high performance liquid chromatography and UV detection (HPLC–UV). Water (disperser solvent) containing tert‐octylphenol ethoxylate (7.5EO) as extraction solvent, was rapidly injected into a warmed sample solution and cloudy state formed immediately. After that, phase separation was performed by centrifugation. The surfactant‐rich phase was diluted with acetonitrile and injected into a HPLC–UV apparatus. The influence of several important parameters on the extraction efficiencies was evaluated. Under optimized experimental conditions, the calibration graphs were linear in the range of 0.06–1,500 µg L^?1 for target analytes. Coefficient of determination (r²) ranged from 0.9985 to 0.9994. The limits of detection were in the range of 0.05–17.1 µg L^?1. The new method was successfully applied with satisfactory results for analysis of target analytes in spiked samples. The relative mean recoveries of the spiked samples ranged from 91.8 to 107.1 % with relative standard deviations in the range of 2.1 to 4.3 %.     

Spam query detection using stream clustering

Nowadays, search engines play a gateway role for users to access their needed information in the Web. However, malicious users can also use them to facilitate their attacks by submitting excessive amounts of bot-generated queries, called spam queries. In this paper, we propose a novel semi-supervised method which can effectively detect spam queries in a practical manner. We first train a model to characterize normal and malicious users, using the linguistic properties of queries as well as the behavioral characteristics of users and IP addresses. Then, we use the trained model to predict the label of arriving requests with a fast and efficient algorithm which works based on the stream clustering approach. The results of our evaluation with the real log of a local search engine show that the proposed algorithm yields an accuracy of about %94, while incurring a low response-time and memory overhead.     

Investigation on performance of microbial fuel cells based on carbon sources and kinetic models

Substrate concentration has great influence on the electrical performance of a microbial fuel cell (MFC). In this study, date syrup with a high sugar content and diversified types of nutrients was used as a substrate in a dual‐chambered MFC. The results obtained were compared with glucose as a conventional substrate for power generation. A pure culture of Saccharomyces cerevisiae was used as a biocatalyst in the anode chamber and potassium ferricyanide as an oxidizing agent in the cathode side. Maximum power density of 65 mW/m² was obtained in an MFC operated with date syrup at an equivalent total carbohydrate content of 6 g/l. When the electron acceptor in the cathode side was replaced with potassium permanganate, power density was increased almost 2.5‐fold and reached 234 mW/m². The system was loaded with low to high concentrations of sugar (1–7, 10, 20 and 30 g/l). However, at high concentrations of substrates, an inverse relationship with the MFC electrical performance was observed, which was most probably due to substrate inhibition in the MFC. Substrate inhibition models were applied to investigate inhibition kinetic from an electrical point of view. Tessier, Aiba and Haldane as inhibition models were well fitted with experimental data (R² = 0.98–0.99). The tested models revealed that the inhibitory effect for the substrate can be described in terms of model parameters. In order to evaluate the effect of the concentration of substrates on electrical performance, different inhibition concentrations were suggested by the models with respect to electrical responses achieved in the MFC. Copyright © 2012 John Wiley & Sons, Ltd.     

Preparation,characterization and photochemical degradation of dyes under UV light irradiation by inorganic–organic nanocomposite

An inorganic–organic nanocomposite consisting of 12-tungstophosphoric acid (H₃PW₁₂O₄₀) supported on Polyaniline (PANI) has been successfully synthesized by one-step and two-step methods. X-ray diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy and electronic absorption spectroscopy indicated that the Polyphosphotungstate (PPT) was chemically attached to the PANI support; the primary Keggin structure remained intact. The photocatalytic and sonocatalytic activity of PPT/PANI was tested by degradation of organic dyes such as Methylene Blue, Rhodamin B, Bromothymol Blue, Methyl Orange and Nylosan Black 2-BC in aqueous solution; the nanocomposite showed higher photocatalytic and sonocatalytic activity than pure polyphosphotungstate or pure PANI.     

Application of ANN and RSM techniques for modeling electrospinning process of polycaprolactone

Neural Computing and Applications - Due to increasing application of nanofibers in many research fields, comprehensive knowledge of the electrospinning process as the most popular method of fiber...     

Examination of Relationship Between Mercury Rate with Zinc and Copper Changes in Muscle Tissue of <Emphasis Type="Italic">Otolithes Rubber</Emphasis> in Mahshahr Port—the Persian Gulf

The current study was conducted with the aim of examination of changes scope as well as correlation between mercury with zinc and copper in the muscle tissue of tigertooth croaker as one of the most consumed fish in the area (Mahshahr Port) and its comparison with available standards. The obtained results suggested that, total average concentration of Hg, Zn and Cu (mean ± SE) accumulated in the muscle tissue of tigertooth croaker (Otolithes rubber) are respectively equal to 1426 ± 113; 15999 ± 1045 and 2279 ± 94 (ngg^–1) in summer as well as 955 ± 91; 13172893 and 1678 ± 178 (ngg^–1) in winter. Comparison among accumulation rate of elements Hg, Cu and Zn in two seasons showed a significant correlation between two mentioned seasons for Zn and Hg. The correlation result indicates a positive significant relationship between zinc and copper and a descending significant relationship between Hg with Cu and Zn. Concentration of total mercury accumulated in the muscle tissue of tigertooth croaker (Otolithes rubber) within two seasons, summer and winter, are lower than standard limit (500 ngg^–1) defined by WHO while it is higher than standard limit (300 ngg^–1) estimated by USEPA. Due to high concentrations of Hg, the results can be a serious warning for consumption of this fish in Mahshahr region.