Maghnite: novel inorganic reinforcement for single-step synthesis of PDMS nanocomposites with improved thermal,mechanical and textural properties

Research on Chemical Intermediates - A simple and efficient strategy was discussed for the synthesis of polydimethylsiloxane nanocomposites, based on the in situ sonochemical polymerization of...     

Green strategy for the synthesis of polyurethane by a heterogeneous catalyst based on activated clay

Research on Chemical Intermediates - A green synthetic route is proposed to obtain polyurethane with a controlled structure, by using maghnite-H+ as an environmentally friendly heterogeneous...     

Some Functional Large Deviations Principles in?Nonparametric Function Estimation

In this paper, we investigate functional large deviation behaviors of some nonparametric function estimates. As a first step, we define a a vector process W _n and study its large deviation behavior in the space L ₁×L ₁×L ₁ with respect to the weak convergence topology. As by-products, we derive large deviation principles in the L ₁-space equipped with the weak convergence topology simultaneously for several density and regression estimators built up using the delta-sequence estimation method.     

VCB: An Efficient Resource Sharing Scheme for Cellular Mobile Systems

A new algorithm called Virtual Channel Borrowing (VCB) used to improve the resource sharing performance of a Fixed Channel Assignment (FCA) scheme is proposed and analyzed. The underlying idea is to exploit regions of cell overlap to achieve a balanced distribution of traffic load in non uniform traffic conditions while reducing call blocks and handoff failures. Simulation results show a performance improvement at the expense of additional signaling. Another advantage of VCB is that it can be integrated easily with small additional cost.     

Choix optimal du paramètre de lissage pour les U-statistiques conditionnelles

This Note proposes a procedure based on the cross-validation method to select the smoothing parameter of the conditional U-statistics. We state here that the obtained data-driven bandwidths are asymptotically optimal with respect to various criteria. Notice that by suitable choices of the U-statistic kernel, say φ, our results allow to deduce in a straightforward way the optimal smoothing parameter of various usual nonparametric estimates.     

Deciphering common failures in molecular docking of ligand-protein complexes

Common failures in predicting crystal structures of ligand-protein complexes are investigated for three ligand-protein systems by a combined thermodynamic and kinetic analysis of the binding energy landscapes. Misdocked predictions in ligand-protein docking are classified as `soft' and `hard' failures. While a soft failure arises when the search algorithm is unable to find the global energy minimum corresponding to the crystal structure, a hard failure results from a flaw of the energy function to qualify the crystal structure as the predicted lowest energy conformation in docking simulations. We find that neither the determination of a single structure with the lowest energy nor finding the most common binding mode is sufficient to predict crystal structures of the complexes, which belong to the category of hard failures. In a proposed hierarchical approach, structural similarity clustering of the conformations, generated from equilibrium simulations with the simplified energy function, is followed by energy refinement with the AMBER force field. This protocol, that involves a hierarchy of energy functions, resolves some common failures in ligand-protein docking and detects crystallographic binding modes that were not found during docking simulations.     

Crystal structure of anhydrous bismuth iodate, Bi(IO3)3

Bismuth iodate was synthesized by precipitation from bismuth nitrate and iodic acid. The powder was dissolved in dilute nitric acid and single crystals were obtained by slow evaporation at 70°C. Bi(IO₃)₃ crystallizes in the monoclinic system, space group P2₁/n (N° 14), a = 8.8882(2) Å, b = 5.9445(2) Å, c = 15.2445(5) Å, = 97.064(1) Å. BiO9 polyhedra are edge-connected forming chains parallel to the b axis; these chains are linked through (IO₃) groups forming layers parallel to (101). The 3D framework is designed by linking these layers through long I–O bonds. DSC analysis shows a remarkable thermal stability.     

Asymptotic analysis of nonlinear elastic platesAnalyse asymptotique des plaques élastiques non linéaires

We study in this Note the asymptotic analysis of nonlinear elastic plates with varying thickness. We suppose that the material moduli of the plates are anisotropic and nonhomogeneous, and the plates are submitted to body forces, to surfaces forces on the lower and upper faces and to pressure forces on the lateral boundary such that the displacements remains plane. To cite this article: D.A. Chacha, C. R. Mecanique 330 (2002) 581–586.     

Gestion de clés et sécurité multipoint: étude et perspectives

Multicast routing is an efficient communication mechanism for group-oriented applications. Several such applications need security guarantees: authentication, integrity confidentiality and access control. Techniques implementing these security services for point-to-point communications can not be directly used in a group communication settings. Consequently, group communication security has been extensively studied. Much current research has been dedicated to key management, which is a building block for all security mechanisms. In this paper, we describe the different existing approaches for managing keys within a group. We discuss the advantages and drawbacks of key management protocols existing in the literature and present a classification and a comparative study of these protocols. We also provide some criticisms and future directions.