Efficient <Emphasis Type="Italic">Candida rugosa</Emphasis> lipase immobilization on Maghnite clay and application for the production of (<Emphasis Type="Italic">1R</Emphasis>)-(−)-Menthyl acetate

This work focused on the identification of natural, economical, and efficient supports for immobilization of Candida rugosa lipase (CRL) to catalyze the resolution of (±)-menthol. To this purpose, CRL has been immobilized on natural montmorillonite from Algeria (Maghnite-H), ion-exchange resins (Amberjet^®1200-H and Amberjet^®4200-Cl), and diatomaceous earth (Celite^®545). After a preliminary screening of supports, the immobilization of CRL led to a markedly improved enantioselectivity. Excellent enantioselectivity (E ≥ 134) was achieved by the four supported lipases (E = 68 for free enzyme). Compared to the three other supports tested, higher enantioselectivity was observed with Maghnite-H used as immobilization matrix. In this work, the effects of solvent, reaction time, and temperature, on the conversion as well as on enantioselectivity were investigated. The maximum of conversion (% C = 43%) with high enantiomeric excess of products (eep > 99) was obtained when the reaction is catalyzed by CRL immobilized on Maghnite-H at 30 °C for 24 h, and using toluene as selected solvent. Immobilized CRL on Maghnite-H exhibited good thermostability over a wide temperature range (30–90 °C) compared to the free one. These results suggest that CRL immobilized on Maghnite-H has good potential as biocatalyst for the production of (1R)-(?)-menthyl acetate.     

On the higher dimension Boussinesq equation with nonclassical condition

This paper deals with the solvability and uniqueness of a higher dimension mixed nonlocal problem for a Boussinesq equation. Galerkin's method was the main used tool for proving the solvability of the given nonlocal problem. Copyright © 2010 John Wiley & Sons, Ltd.     

Experimental Determination of the Longitudinal Dispersivity During the Injection of a Micro-Cement Grout in a One-Dimensional Soil Column

In order to describe the basic phenomenon of miscible grout propagation during the injection in a saturated and deformable porous medium, a general mathematical model was proposed, which accounts for the existing coupling between the fluid flow analysis, the miscible grout transport, and the solid skeleton deformation, leading to a realistic prediction of the injected zone. The development of the model was made concurrently with laboratory experiments to determine the model parameters. This paper describes the determination of the longitudinal dispersivity during the transport of a micro-cement grout injected in a one-dimensional soil column, by relying on image processing analysis. The application concerned here is the injection of soils for improving their properties, that is, to reduce permeability, increase mechanical strength or reduce the deformability. The longitudinal dispersion coefficient is an essential parameter governing the mixing process and the evolution of the transition zone, and thus the injection efficiency. Finally, the comparison between simulated results from the developed model and experimental data, essential to validate the model from a phenomenological standpoint, is made.     

Global synchronization of fractional‐order and integer‐order N component reaction diffusion systems: Application to biochemical models

This study considers the problem of control and synchronization between fractional‐order and integer‐order, N‐components reaction‐diffusion systems with nonidentical coefficients and different nonlinear parts. The control scheme is designed using the Lyapunov direct method. The results are exemplified by two significant biochemical models, namely, the fractional‐order Lengyel‐Epstein model and the Gray‐Scott model. To illustrate the effectiveness of the proposed scheme, numerical simulations are performed in one and two space dimensions using Homotopy Analysis Method (HAM).     

Piecewise multiplier method and nonlinear integral inequalities for Petrowsky equation with nonlinear dissipation

This work is concerned with obtention of energy decay estimates for Petrowsky equation with a nonlinear dissipation which is active only in an interior subset of the domain. We prove that the piecewise multiplier method as introduced by [20] and [22] for the wave equation can be extended to the Petrowsky equation. Moreover, we also apply some recent results by the author to obtain precise decay rate estimates for the energy, without specifying the growth of the nonlinear dissipation close to the origin by means of convex properties and nonlinear integral inequalities for the energy of the solutions.     

General decay for a class of viscoelastic problem with not necessarily decreasing kernel

In this paper, a problem which arises in a class of viscoelasticity is considered. We obtain the decay rate of the energy, for certain class of relaxation functions not necessarily exponentially or polynomially decaying to zero.     

Anion Directed Self‐Assembly of One‐Dimensional and Two‐Dimensional Coordination Polymers Containing Bridging Diphosphine Ligands

The reactions of 1,2‐bis(diphenylphosphanyl)ethane (dppe) with different silver(I) salts facilitated the formation of 1D and 2D coordination polymers, [Ag(dppe)(OAc)]_n · nH₂O ( 1 ) and [Ag₂(dppe)_1.5(NO₃)₂]_n ( 2 ), respectively. The complexes were characterized by elemental analysis, ATR‐IR spectroscopy, ¹H NMR, ¹³C NMR, and ³¹P NMR spectroscopy, and single‐crystal X‐ray diffraction. Structural analysis revealed that complex 1 exhibits a 1D infinite wavy structure, in which each silver(I) ion is bridged by dppe ligands. Structure 2 has a 2D topologically promising architecture that displays a 6.6.6 graphitic net, which corresponds to hnd topology. The nitrate ions and dppe ligands are in a μ₂ bridging mode and support the formation of this net. Moreover, significant π–π interactions between the phenyl rings in the apertures of (6,3) grid stabilized complex 2 .     

The determination of tissue-specific DNA methylation patterns in forensic biofluids using bisulfite modification and pyrosequencing

The goal of this study is to explore the application of epigenetic markers in the identification of biofluids that are commonly found at the crime scene. A series of genetic loci were examined in order to define epigenetic markers that display differential methylation patterns between blood, saliva, semen, and epithelial tissue. Among the different loci tested, we have identified a panel of markers, C20orf117, ZC3H12D, BCAS4, and FGF7, that can be used in the determination of these four tissue types. Since methylation modifications occur at cytosine bases that are immediately followed by guanine bases (CpG sites), methylation levels were measured at CpG sites spanning each marker. Up to 11 samples of each tissue type were collected and subjected to bisulfite modification to convert unmethylated CpG-associated cytosine bases to thymine bases. The bisulfite modified DNA was then amplified via nested PCR using a primer set of which one primer was biotin labeled. Biotinylated PCR products were in turn analyzed and the methylation level at each CpG site was quantitated by pyrosequencing. The percent methylation values at each CpG site were determined and averaged for each tissue type. The results indicated significant methylation differences between the tissue types. The methylation patterns at the ZC3H12D and FGF7 loci differentiated sperm from blood, saliva, and epithelial cells. The C20orf117 locus differentiated blood from sperm, saliva, and epithelial cells and saliva was differentiated from blood, sperm, and epithelial cells at a fourth locus, BCAS4. The results of this study demonstrate the applicability of epigenetic markers as a novel tool for the determination of biofluids using bisulfite modification and pyrosequencing.     

Analysis of dynamic pull-in voltage and response time for a micro-electro-mechanical oscillator made of power-law materials

Nonlinear Dynamics - Analysis of dynamic pull-in voltage for a micro-electro-mechanical oscillator of platform type is performed. The lumped mass model for the actuated micro-cantilever beam made...     

Efficient multicomponent synthesis of 2-aminopyridines catalysed by basic mesoporous materials

Research on Chemical Intermediates - An efficient and green procedure for the synthesis of 2-aminopyridines derivatives via four-component reaction of acetophenone, malononitrile, triethoxymethane...