Antioxidant protective effect of honey in cigarette smoke-induced testicular damage in rats

Cigarette smoke (CS) can cause testicular damage and we investigated the possible protective effect of honey against CS-induced testicular damage and oxidative stress in rats. CS exposure (8 min, 3 times daily) and honey supplementation (1.2 g/kg daily) were given for 13 weeks. Rats exposed to CS significantly had smaller seminiferous tubules diameter and epithelial height, lower Leydig cell count and increased percentage of tubules with germ cell loss. CS also produced increased lipid peroxidation (TBARS) and glutathione peroxidase (GPx) activity, as well as reduced total antioxidant status (TAS) and activities of superoxide dismutase (SOD) and catalase (CAT). However, supplementation of honey significantly reduced histological changes and TBARS level, increased TAS level, as well as significantly restored activities of GPx, SOD and CAT in rat testis. These findings may suggest that honey has a protective effect against damage and oxidative stress induced by CS in rat testis.     

Removal of antimony (III) by multi-walled carbon nanotubes from model solution and environmental samples

Multi-walled carbon nanotubes (MWCNTs) are used for the adsorption and removal of Sb(III) from model solutions and real environmental samples. The effects of different factors that affect the adsorption process; the results showed that most of the Sb(III) ions were removed from the solution within 30 min, at pH 7.0, using 200 mg MWCNTs. Further, it was observed that the adsorption process was greatly enhanced by lowering the solution temperature, which indicated the exothermic nature of the adsorption. The adsorption study was analyzed kinetically, using different kinetic models, and the results showed that the adsorption of Sb(III) by MWCNTs from the model solution followed pseudo-second-order kinetics with good correlation coefficients. In addition, it was found that the adsorption of Sb(III) occurred in more than one step, including the liquid film diffusion of the Sb(III) ions from the aqueous phase through the liquid film around the MWCNTs and further intra-particle diffusion through the nanotubes’ bundles and aggregates.     

Catalytic hydrogen adsorption of nano-crystalline hydrotalcite derived mixed oxides

Nano-crytalline hydrotalcite derived reduced mixed oxides containing magnesium, nickel and aluminium (MNAM) have been synthesized using coprecipitation and showed successfully nickel catalysed reversible hydrogen adsorption using the temperature programmed technique under near ambient conditions. ICP-MS and XRD analysis ensured the adsorbent homogeneity and different crystalline phases of mixed oxides. Morphology and textural properties of mixed oxides have been explored using the FESEM, BET and HRTEM analysis techniques. Nano-crystalline and mesporous reduced mixed oxides exhibited a 3.9 wt% H₂ adsorption capacity in where desorption capacity was 1.9 wt% H₂. Hydrogen adsorbed surface and different phases were analysed by XPS, Raman and FTIR analysis techniques. The hydrogen adsorption enthalpy (ΔH) and entropy (ΔS) changes of reduced mixed oxides were −47.58 kJ/mol and −120.98 J/mol K, respectively, and the promising desorption activation energy of 65 kJ/mol correspond its reversibility as potential energy storage material.     

Optimized intrusion detection mechanism using soft computing techniques

Intrusion detection is an important technique in computer and network security. A variety of intrusion detection approaches be present to resolve this severe issue but the main problem is performance. It is important to increase the detection rates and reduce false alarm rates in the area of intrusion detection. Therefore, in this research, an optimized intrusion detection mechanism using soft computing techniques is proposed to overcome performance issues. The KDD-cup dataset is used that is a benchmark for evaluating the security detection mechanisms. The Principal Component Analysis (PCA) is applied to transform the input samples into a new feature space. The selecting of an appropriate number of principal components is a critical problem. So, Genetic Algorithm (GA) is used in the optimum selection of principal components instead of using traditional method. The Support Vector Machine (SVM) is used for classification purpose. The performance of this approach is addresses. Further, a comparative analysis is made with existing approaches. Consequently, this method provides optimal intrusion detection mechanism which is capable to minimize amount of features and maximize the detection rates.     

Correlation of electrical and swelling properties with nano free‐volume structure of conductive silicone rubber composites

The present study focuses on finding a correlation between the positron annihilation parameters of silicone rubber polydimethylsiloxane (PDMS) composites loaded with different conductive fillers and their swelling and electrical properties. Four types of conductive fillers have been used in this study, i.e., carbon black (CB), graphite (G), copper, and nickel powders. The investigated swelling parameters for PDMS composites such as the maximum degree of swelling Q_m%, the penetration rate, P, and consequently the diffusion coefficient, D, decreased with increasing the filler content due to the reduction of the size of free‐volume, which could be observed through a decrease of the probability of ortho‐positronium (o‐Ps) formation I₃, that has been measured by the positron annihilation spectroscopy (PALS). Accordingly, a positive correlation has been found of 76.78% and 61.1% between Q_m% and the o‐Ps lifetime τ₃, representing the size of free‐volume for the CB and G filled composites, respectively. It is worthwhile, mentioning that the CB filled composites exhibit relatively low values of P, D, and Q_m% as compared to the G filled composites due to the difference in the physical properties of the filler, particle size, surface area as well as the tendency of the filler particles to make aggregates. On the other hand, the variation of the diffusion coefficient with the relative fractional free‐volume F_r is found in good agreement with the Fujita's free‐volume theory. On the other hand, the electrical conductivity increases with increasing the conductive filler content. Positive temperature coefficient of conductivity (PTCC) behavior is detected, except for the composite containing 20 or 25 phr CB, which showed a metallic behavior. Besides, CB filled PDMS composites exhibit higher electrical conductivity as compared to the composites filled with the other three fillers. The electrical conductivity ln (σ) is positively correlated with the probability of free annihilation of positrons at interfaces I₂, thus suggesting an increase in the electron density with the filler content. The activation energy of conduction, E_a, decreases with the increase in the loading of conductive filler. Moreover, it was noticed that E_a varies with the filler type, the values of E_a increase as the particle size of the filler increases. Finally, a correlation between the free‐volume V_f, determined by PALS with the DC electrical conductivity ln(σ) is found to be in accordance with Miyamoto and Shibayma model. POLYM. COMPOS., 34:2105–2115, 2013. © 2013 Society of Plastics Engineers     

Performance of Layered Steered Space–Time Codes in Wireless Systems

Layered Steered Space–Time Codes (LSSTC) is a recently proposed multiple-input multiple-output (MIMO) system that combines the benefits of vertical Bell Labs space–time (VBLAST) scheme, space–time block codes (STBC) and beamforming. In this paper, we derive the error performance and capacity of a single-user LSSTC system. The analysis is general enough to any layer ordering and modulation schemes used. In addition, the derived analysis is general for any LSSTC structure in which layers may have different number of antenna arrays and may be assigned power according to any power allocation. Furthermore, we analytically investigate the tradeoff between the main parameters of the LSSTC system, i.e., diversity, multiplexing and beamforming. Our results give recursive expressions for the probability of error for LSSTC which showed nearly perfect match to the simulation results. Results have also revealed the possibility of designing an adaptive system in which it was shown that combining beamforming, STBC, and VBLAST has better performance than VBLAST at high SNR range.     

Synthesis of uranium nitride by a mechanically induced gas-solid reaction

A high energy, low-temperature, ball-milling route was used to directly produce uranium nitride. Pure uranium metal particles (∼100 μm) were ball milled under a 420 kPa nitrogen atmosphere for 24 h at ambient temperature to yield phase pure U₂N₃ powder as confirmed by X-ray diffraction and energy dispersive spectroscopy. The median particle size was measured to be approximately 6 μm.