Antioxidant and free radical scavenging activities of phenols from onion (Allium cepa)

Four (red, violet, white and green) varieties of Allium cepa were studied for their total phenolic contents (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA). The TPC varied from 4.6 to 74.1 mg/g GAE, AOA varied from 13.6% to 84.1% and FRSA showed wide range in terms of IC₅₀ (inhibitory concentration) from 0.1 to 15.2 mg/ml, EC₅₀ (efficient concentration) from 4.3 to 660.8 mg/mg and ARP (antiradical power) from 0.15 to 23.2. The outer dry layers of red and violet varieties showed better inhibition of lipid peroxidation assayed by ammonium thiocyanate than α-tocopherol. The non-site-specific inhibition of hydroxyl radical induced deoxyribose degradation was also higher in the outer dry layers of red and violet varieties than in their middle and inner layers. The outer layers were also potential inhibitors of nitroblue tetrazolium chloride (NBT) reduction caused by superoxide anions. On the other hand the ferrous ion chelating capacity of the red and violet varieties was highest in the inner layers. Specific phenolic composition performed through HPLC and LC–MS/MS showed the presence of gallic acid, ferulic acid, protocatechuic acid, quercetin, and kaempferol. The unutilised outer layers of the red variety were a rich source of quercetin (5110 μg/g) with high AOA, FRSA and also showed significant protection of DNA damage caused by free radicals.     

Multifunctional biodegradable lube oil additives: Synthesis,characterization, and performance evaluation

Copolymers of different concentration of decyl acrylate and 1-decene with rice bran oil were prepared and their characterization was carried out by spectral (NMR, IR), thermogravimetric, and gel permeation chromatography analysis. Performance evaluation of them in lube oil indicates that the polymers effectively act as pour point depressant and viscosity modifier. The viscosity index and pour point values depend on the nature of mineral base oils, polymer type, and also on the concentration of the additives in solution. Biodegradability test was also carried out and as anticipated, the rice bran oil–copolymers showed excellent biodegradable nature among the additives.     

Magnetocaloric effect in temperature-sensitive magnetic fluids

The magnetocaloric properties of three different temperature-sensitive magnetic fluids were studied. The pyromagnetic coefficient for all the materials were obtained and it was found that this property depends on physical and magnetic properties like size, magnetization and Curie temperature. A theoretical model was developed to explain the behaviour of change in entropy with temperature.     

Effect of Plant Derived Antimicrobials on Salmonella Enteritidis Adhesion to and Invasion of Primary Chicken Oviduct Epithelial Cells in vitro and Virulence Gene Expression

Salmonella Enteritidis (SE) is a major foodborne pathogen in the United States and one of the most frequently reported Salmonella serotypes globally. Eggs are the most common food product associated with SE infections in humans. The pathogen colonizes the intestinal tract in layers, and migrates to reproductive organs systemically. Since adhesion to and invasion of chicken oviduct epithelial cells (COEC) is critical for SE colonization in reproductive tract, reducing these virulence factors could potentially decrease egg yolk contamination. This study investigated the efficacy of sub-inhibitory concentrations of three plant-derived antimicrobials (PDAs), namely carvacrol, thymol and eugenol in reducing SE adhesion to and invasion of COEC, and survival in chicken macrophages. In addition, the effect of PDAs on SE genes critical for oviduct colonization and macrophage survival was determined using real-time quantitative PCR (RT-qPCR). All PDAs significantly reduced SE adhesion to and invasion of COEC (p < 0.001). The PDAs, except thymol consistently decreased SE survival in macrophages (p < 0.001). RT-qPCR results revealed down-regulation in the expression of genes involved in SE colonization and macrophage survival (p < 0.001). The results indicate that PDAs could potentially be used to control SE colonization in chicken reproductive tract; however, in vivo studies validating these results are warranted.     

Large deformation flexural behavior of laminated composite skew plates: An analytical approach

The paper presents the large deformation flexural response of composite laminated skew plates subjected to uniform transverse pressure. Third order shear deformation theory (TSDT) and von-Karman’s nonlinearity is used for the analysis. Skew domain is mapped into a square domain and finite degree double Chebyshev series is used to discretize the space domain. No grid generation is required in the present solution technique. The nonlinear equations are linearized using quadratic extrapolation technique and the behavior of moderately thick laminated composite skew plates is studied. The effects of geometric nonlinearity, transverse shear, boundary conditions, aspect ratio and modular ratio on the behavior of laminated composite skew plates are discussed in detail.     

Synthesis and luminescence properties of rare earth doped gamma-ray-irradiated GdCa4O(BO3)3 phosphors

Undoped and rare earth (RE = Ce, Dy, and Eu) doped GdCa₄O(BO₃)₃ phosphors were synthesized by solid-state diffusion technique. Formation of the sample was confirmed by taking X-ray diffraction (XRD) pattern of the sample. Photoluminescence (PL) emission spectrum showed characteristic emission of RE doped in the GdCa₄O(BO₃)₃ sample. It is observed that doping of RE ion initially enhanced the TL yield, attained an optimum TL for a particular concentration of dopant (i.e., 0.5 mol%) then decreased with further increase in dopant concentration for all the samples. We found that Ce is the best activator for enhancing the TL yield in GdCa₄O(BO₃)₃ system. Fading of TL intensity of the sample was studied and it is found that fading of the TL is about 5% over the period of 15 days. The simple glow curve, linear response to γ-ray dose and less fading; makes the GdCa₄O(BO₃)₃:Ce(0.5 mol%) phosphors a suitable candidate for TL dosimetry.     

In situ redox flexibility of FeII-III Oxyhydroxycarbonate green rust and fougerite

Bacterial activity is commonly thought to be directly responsible for denitrification in soils and groundwater. However, nitrate reduction in low organic sediments occurs abiotically by FeII ions within the fougerite mineral (IMA 2003-057), giving the bluish-green color of gleysols. Fougerite, the mineral counterpart of FeII-III oxyhydroxycarbonate, FeII6(1-x)FeIII6xO12H2(7-3x)CO3, provides a unique in situ redox flexibility, which can adapt x = {[FeIII]/[Fetotal]} between 1/3 and 2/3 as shown using M?ssbauer spectroscopy. Chemical potential and Eh-pH diagrams for this system were determined from electrode potential monitored during deprotonation of hydroxycarbonate FeII4FeIII2(OH)12CO3 to assess the possibility of reducing pollutants in the field. Bioreduction of ferric oxyhydroxides in anoxic groundwater yields dissolved FeII, whereas HCO3- anions produced from organic matter are incorporated into fougerite layered double oxyhydroxide structure. Thus, fougerite is the solid-state redox mediator acting as electron shuttle that helps bacterial activity for reducing nitrate by coupling dissimilatory FeIII reduction and oxidation of FeII with reduction of NO3-. It is proposed that this system could be used in the remediation of soils and nitrified waters.     

Weibull extension model: A Bayes study using Markov chain Monte Carlo simulation

Several generalizations of the two-parameter Weibull model have been proposed to model data sets that exhibit complex non-monotone shapes of hazard rate function. The present paper focuses on one such generalization referred to as the Weibull extension model in the literature. Complete Bayesian analysis of the model has been provided using Markov chain Monte Carlo simulation. Finally, a thorough study has been conducted for checking the adequacy of the model for a given data set using some of the graphical and numerical methods based on predictive simulation ideas. A real data set is considered for illustration.     

Locating the critical failure surface in a slope stability analysis by genetic algorithm

The slope stability analysis is routinely performed by engineers to evaluate the stability of embankment dams, road embankments, river training works, excavations and retaining walls. Locating the critical failure surface of a soil slope is rendered erroneous and cumbersome due to the existence of local minima points. In case of large soil slopes, engineers face with a search space too large to employ the trial and error method in a computationally efficient fashion. A genetic algorithm is proposed to locate the critical surface under general conditions with general constraints. Convergence to any prescribed degree of precision was achieved with the algorithm. The algorithm has been demonstrated to be computationally superior to other optimization routines, like, Monte-Carlo method and grid-points approach.