Numerical and theoretical study of weak Galerkin finite element solutions of Turing patterns in reaction–diffusion systems

In this paper, we introduce numerical schemes and their analysis based on weak Galerkin finite element framework for solving 2‐D reaction–diffusion systems. Weak Galerkin finite element method (WGFEM) for partial differential equations relies on the concept of weak functions and weak gradients, in which differential operators are approximated by weak forms through the Green's theorem. This method allows the use of totally discontinuous functions in the approximation space. In the current work, the WGFEM solves reaction–diffusion systems to find unknown concentrations (u, v) in element interiors and boundaries in the weak Galerkin finite element space WG(P₀, P₀, RT₀) . The WGFEM is used to approximate the spatial variables and the time discretization is made by the backward Euler method. For reaction–diffusion systems, stability analysis and error bounds for semi‐discrete and fully discrete schemes are proved. Accuracy and efficiency of the proposed method successfully tested on several numerical examples and obtained results satisfy the well‐known result that for small values of diffusion coefficient, the steady state solution converges to equilibrium point. Acquired numerical results asserted the efficiency of the proposed scheme.     

An exact feature selection algorithm based on rough set theory

Feature reduction based on rough set theory is an effective feature selection method in pattern recognition applications. Finding a minimal subset of the original features is inherent in rough set approach to feature selection. As feature reduction is a Nondeterministic Polynomial‐time‐hard problem, it is necessary to develop fast optimal or near‐optimal feature selection algorithms. This article aims to propose an exact feature selection algorithm in rough set that is efficient in terms of computation time. The proposed algorithm begins the examination of a solution tree by a breadth‐first strategy. The pruned nodes are held in a version of the trie data structure. Based on the monotonic property of dependency degree, all subsets of the pruned nodes cannot be optimal solutions. Thus, by detecting these subsets in trie, it is not necessary to calculate their dependency degree. The search on the tree continues until the optimal solution is found. This algorithm is improved by selecting an initial search level determined by the hill‐climbing method instead of searching the tree from the level below the root. The length of the minimal reduct and the size of data set can influence which starting search level is more efficient. The experimental results using some of the standard UCI data sets, demonstrate that the proposed algorithm is effective and efficient for data sets with more than 30 features. © 2014 Wiley Periodicals, Inc. Complexity 20: 50–62, 2015     

Hyper-cross-linked β-cyclodextrin nanosponge: a three-dimensional,porous and biodegradable catalyst in the one-pot synthesis of kojic acid-based heterocyclic compounds

Research on Chemical Intermediates - In the present study, β-cyclodextrin-based nanosponges were prepared by reaction of β-cyclodextrin with dicarbonyl imidazole as a crosslinker agent....     

Characterization of hydrocortisone biometabolites and 18S rRNA gene in Chlamydomonas reinhardtii cultures

A unicellular microalga, Chlamydomonas reinhardtii, was isolated from rice paddy-field soil and water samples and used in the biotransformation of hydrocortisone (1). This strain has not been previously tested for steroid bioconversion. Fermentation was carried out in BG-11 medium supplemented with 0.05% substrate at 25 degrees C for 14 days of incubation. The products obtained were chromatographically purified and characterized using spectroscopic methods. 11b,17 beta-Dihydroxyandrost-4-en-3-one (2), 11 beta-hydroxyandrost-4-en-3,17-dione (3), 11 beta,17 alpha,20 beta,21-tetrahydroxypregn-4-en-3-one (4) and prednisolone (5) were the main products of the bioconversion. The observed bioreaction features were the side chain degradation of the substrate to give compounds 2 and 3 and the 20-ketone reduction and 1,2-dehydrogenation affording compounds 4 and 5, respectively. A time course study showed the accumulation of product 2 from the second day of the fermentation and of compounds 3, 4 and 5 from the third day. All the metabolites reached their maximum concentration in seven days. Microalgal 18S rRNA gene was also amplified by PCR. PCR products were sequenced to confirm their authenticity as 18S rRNA gene of microalgae. The result of PCR blasted with other sequenced microalgae in NCBI showed 100% homology to the 18S small subunit rRNA of two Chlamydomonas reinhardtii spp.     

An aptamer for recognizing the transmembrane protein PDL-1 (programmed death-ligand 1), and its application to fluorometric single cell detection of human ovarian carcinoma cells

Microchimica Acta - Programmed death-ligand 1 (PD-L1) is overexpressed in a variety of cancer cells. Using protein SELEX, aptamers against PD-L1 were identified. After 10 rounds of selection, 2...