An efficient glucose-based ligand for Heck and Suzuki coupling reactions in aqueous media

The glucose-based ligand, N-salicylidene-d-glucosamine (Sal-d-glsmN), was readily obtained by reaction of salicylaldehyde (Hsal) with the d-glucosamine hydrochloride. Ligand Sal-d-glsmN was found to be an efficient ligand in the palladium-catalyzed Suzuki and Heck C–C coupling reactions in aqueous medium under aerobic condition. It was found that the use of Sal-d-glsmN/Pd(OAc)₂ system as a catalyst, aryl halides undergo Suzuki and Heck cross-couplings, respectively, with arylboronic acids and olefins to give the desired products in moderate to excellent yields.     

Novel ion-imprinted polymer coated on nanoporous silica as a highly selective sorbent for the extraction of ultratrace quantities of gold ions from mine stone samples

We have developed a gold ion-imprinted polymer (GIP) by incorporating a dipyridyl ligand into an ethylene glycol dimethacrylate matrix which then was coated onto porous silica particles. The material was used for the selective extraction of ultratrace quantities of gold ion from mine stones, this followed by its quantitation by FAAS. The effects of concentration and volume of eluent, pH of the solution, flow rates of sample and eluent, and effect of potentially interfering ions, especially palladium and platinum, was investigated. The limit of detection is <0.2 ng?mL^?1, the precision (RSD%) is 1.03 %, and recoveries are >99 %. In order to show the high selectivity and efficiency of the new sorbent, the results were compared to those obtained with more simple sorbents possessing the same functional groups. The accuracy of the method was demonstrated by the accurate determination of gold ions in a certified reference material. To the best of our knowledge, there is no report so far on an imprint for gold ions that has such a selectivity over Pd(II) and Pt(II) ions.

Efficient quadrature rules with a priori error estimates for integrands with end point singularities

In this paper we present details of an efficient numerical integration rule based upon error function transformation of the integration variable. We also derive an a priori error estimate for our method and present numerical results to highlight various features of the rule as applied to integrals with end point singularities in the low order derivatives of their integrands.     

Restricted algebras on inverse semigroups I,representation theory

The relation between representations and positive definite functions is a key concept in harmonic analysis on topological groups. Recently this relation has been studied on topological groupoids. This is the first in a series of papers in which we have investigated a similar relation on inverse semigroups. We use a new concept of “restricted” representations and study the restricted semigroup algebras and corresponding C *‐algebras. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Investigation of the Preyssler phosphotungstate heteropolyanion, [NaP5W30O110]14−, properties with different counter ions

Preyssler heteropolytungstophosphate anions with different counter ions, X _x M _y [NaP₅W₃₀O₁₁₀], where X = H and M = Cs, Ba, La, Ce, Hg, Tl, Pb and Bi, were prepared and the effect of the counter ion on their behavior was investigated by i.r. spectroscopy, surface area measurements (BET), simultaneous thermal analysis (STA), cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). Thermal analyses indicate that the Ce derivative has the highest and the Hg derivative the lowest thermal stability. Only the Cs, Ba and Tl salts show measurable surface area. All heteropolyanions with similar i.r. spectra and electrochemical behavior demonstrate that the heteropolyanion structures are retained. The X-ray photoelectron spectra of the heteropolyacid salts reveal high binding energies for counter ions in comparison with classic salts and strong interaction of counter ion with the oxo oxygen's for H⁺ and Cs⁺ derivatives.     

1,3‐Dichloro‐5,5‐dimethylhydantoin (DCDMH) as a New Oxidizing Agent for the Facile and Selective Oxidation of Oximes to Their Carbonyl Compounds

Oximes are converted to the parent carbonyl compounds in good yields when treated with 1,3‐dichloro‐5,5‐dimethylhydantoin (DCDMH) ( 1 ). An optimized procedure has been developed; the simple work‐up minimizes loss of product and oximes have been selectively oxidized in the presence of alcohols and alkenes.     

A line search trust-region algorithm with nonmonotone adaptive radius for a system of nonlinear equations

In this paper, a trust-region procedure is proposed for the solution of nonlinear equations. The proposed approach takes advantages of an effective adaptive trust-region radius and a nonmonotone strategy by combining both of them appropriately. It is believed that selecting an appropriate adaptive radius based on a suitable nonmonotone strategy can improve the efficiency and robustness of the trust-region frameworks as well as decrease the computational cost of the algorithm by decreasing the required number subproblems that must be solved. The global convergence and the local Q-quadratic convergence rate of the proposed approach are proved. Preliminary numerical results of the proposed algorithm are also reported which indicate the promising behavior of the new procedure for solving the nonlinear system.     

Module Arens regularity for semigroup algebras

We extend the concept of Arens regularity of a Banach algebra to the case that there is an -module structure on , and show that when S is an inverse semigroup with totally ordered subsemigroup E of idempotents, then A=ℓ ¹(S) is module Arens regular if and only if an appropriate group homomorphic image of S is finite. When S is a discrete group, this is just Young’s theorem which asserts that ℓ ¹(S) is Arens regular if and only if S is finite. An erratum to this article can be found at     

An Iterative LMI-Based Reduced-Order Observer Design for Fractional-Order Chaos Synchronization

In this paper, attempts are made to design a reduced-order observer for a nonlinear Lipschitz class of fractional-order systems. It is assumed that nonlinear terms not only depend on measurable states but depend on unknown states and inputs as well. The sufficient conditions for stability of the observer based on the Lyapunov technique are derived and converted into linear matrix inequalities (LMIs). To overcome the main drawback of previous research studies which assumed that the sum of terms in infinite series coming from fractional derivative of a Lyapunov function is bounded and its upper bound is predefined, we used an iterative LMI-based algorithm to find out this bound. A four-wing chaotic system is implemented in both PSpice and MATLAB software as a case study. Simulation results are reported to show the effectiveness of the proposed iterative LMI-based reduced-order observer in tracking the unmeasurable state variables of the chaotic fractional system in different initial conditions.     

Crack Damage in Polymers and Composites: A Review

Polymer-based materials are extensively used in various applications such as aircrafts, civilian structures, oil and gas platforms and electronics. They are, however, inherently damage prone and over time, the formation of cracks and microscopic damages influences the thermo-mechanical and electrical properties, which eventually results in the total failure of the materials. This paper provides an overview of the principal causes of cracking in polymer and composites and summarizes the recent progress in the development of non-destructive techniques in crack detection. Furthermore, recent progress in the development of bio-inspired self-healing methods in autonomic repair is discussed.