Antioxidant, Radical Scavenging and Antimicrobial Activities of Red Onion (Allium cepa L) Skin and Edible Part Extracts

The antioxidant, radical scavenging and antimicrobial activities of extracts from skin and edible part of red onion have been investigated. Crude extracts of red onion were obtained separately with acetone, ethanol and mixtures of solvents with water. The amounts of isolated phenolic compounds and quercetin from onion skin were approximately 3 to 5 times higher as from the onion edible part. Antioxidant and radical scavenging activities of onion skin extracts were generally high, results were comparable to that of BHT. Extracts from onion edible part showed somewhat lower activity. Furthermore, high activity of skin extracts against bacteria Escherichia coli, Pseudomonas fluorescens and Bacillus cereus and fungi Aspergillus niger, Trichoderma viride and Penicillium cyclopium was observed. Antimicrobial activity of edible part extracts against tested microorganisms is generally lower, while for Escherichia coli no growth inhibition was observed

Double-diffusive natural convection within a 3D porous enclosure, using the boundary element method

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.A three-dimensional numerical study based on the boundary element method (BEM) was performed in order to study the problem of double-diffusive natural convection within a cubic enclosure filled with a fluid-saturated porous media, and subjected to horizontal temperature and concentration gradients. The fluid-flow within the porous media was modeled using space-averaged Navier-Stokes equations, coupled with energy and species equations. The used numerical algorithm is based on a combination of single domain and sub-domain BEM, and solves the velocity-vorticity formulation of the governing equations. The influences of the main controlling parameters, such as the porous Rayleigh number, Darcy number, Lewis number, and the buoyancy coefficient were investigated, by focusing on those situations, where the flowfield becomes 3D. The results for overall heat and solutetransfer through the porous enclosure are presented in terms of Nusselt and Sherwood numbers as functions of the governing parameters, and then compared to the numerical benchmarks published in literature.mp201

Boundary element formulations for the numerical solution of two-dimensional diffusion problems with variable coefficients

This is the post-print version of the final paper published in Computers & Mathematics with Applications. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.This paper presents new formulations of the radial integration boundary integral equation (RIBIE) and the radial integration boundary integro-differential equation (RIBIDE) methods for the numerical solution of two-dimensional diffusion problems with variable coefficients. The methods use either a specially constructed parametrix (Levi function) or the standard fundamental solution for the Laplace equation to reduce the boundary-value problem (BVP) to a boundary–domain integral equation (BDIE) or boundary–domain integro-differential equation (BDIDE). The radial integration method (RIM) is then employed to convert the domain integrals arising in both BDIE and BDIDE methods into equivalent boundary integrals. The resulting formulations lead to pure boundary integral and integro-differential equations with no domain integrals. Furthermore, a subdomain decomposition technique (SDBDIE) is proposed, which leads to a sparse system of linear equations, thus avoiding the need to calculate a large number of domain integrals. Numerical examples are presented for several simple problems, for which exact solutions are available, to demonstrate the efficiency of the proposed approaches

MTHFR C677T and A1298C Genotypes and Haplotypes in Slovenian Couples with Unexplained Infertility Problems and in Embryonic Tissues from Spontaneous Abortions

The objective of this study was to analyze the methylenetetrahydrofolate reductases (MTHFRs) C677T and A1298C genotype distributions in couples with unexplained fertility problems (UFP) and healthy controls, and to analyze the genotype and haplotype distribution in spontaneously aborted embryonic tissues (SAET) using allele specific polymerase chain reaction (PCR) in 200 probands with UFP, 353 samples of SAET and 222 healthy controls. The analysis revealed a significant overall representation of the 677T allele in male probands from couples with UFP (p = 0.036). The combined genotype distribution for both MTHFR polymorphisms was also significantly altered (χ2 21.73, p <0.001) although female probands made no contribution (c2 1.33, p = 0.72). The overall representation of the 677T allele was more pronounced in SAET (0.5 vs. 0.351 in controls, p <0.001) regardless of the karyotype status (aneuploidy vs. normal karyotype). In addition, the frequencies of the CA and CC haplotypes were significantly lower than in the control group (p = 0.021 and p = 0.001, respectively), whereas the frequency of the TC haplotype was significantly higher than in controls (p <0.0001). The presented findings indicate that only male probands contribute to the association of MTHFR mutations with fertility problems in grown adults and demonstrate a high prevalence of mutated MTHFR genotypes in SAET