Separation and analysis of triazine herbcide residues by capillary electrophoresis

Triazines are widely used in agriculture around the world as selective pre‐ and post‐emergence herbicides for the control of broad leaf and grassy weeds. With high toxicity and persistence, triazines can contaminate the environment and crops, so the development of rapid and sensitive methods for the determination of different triazines is necessary. Capillary electrophoresis comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities. This review focuses on the analysis of triazine herbicides with different modes of capillary electrophoresis, including capillary zone electrophoresis, micellar electrokinetic capillary electrophoresis, capillary electrochromatography and nonaqueous capillary electrophoresis. Determinations of triazines in various matrices such as surface water, groundwater, vegetables, soil and grains are emphasized. Copyright © 2014 John Wiley & Sons, Ltd.     

Hyperfine magnetic fields at sp-sites in Co2YZ Heusler alloys

The systematics of hyperfine magnetic fields at sp impurities on the Z-sites in Co based Heusler alloys are investigated. New TDPAC measurements of Cd hyperfine fields are reported.     

Statistical properties of the nonlinear negative binomial state

In this context, we introduce and investigate the properties of the nonlinear negative binomial state (the state which interpolates between the nonlinear coherent and the number states). Mainly we concentrate on the statistical properties for such state where we have discussed two different cases of squeezing phenomenon. The first case is the normal squeezing while the second is the amplitude squared squeezing, further the second order correlation function is also considered. Our discussion have been extended to include the quasi-probability distribution functions (W-Wigner and Q-functions). The quadrature distribution and the phase properties in Pegg-Barnett formalism besides the phase variances are considered. Examination of the resonance fluorescence against the present state is given (single atom and thermodynamic limit). It has been shown that the atomic inversion is sensitive to any variation in the nonlinear negative binomial number m.     

Integrable non-linear σ models with fermions

The two-dimensional non-linear model on a Riemannian symmetric spaceM=G/H is coupled to fermions with quartic self-interactions. The resulting hybrid model is presented in a gauge-dependent formulation, with a bosonic field taking values inG and a fermionic field transforming under a given representation of the gauge groupH. General criteria for classical integrability are presented: they essentially fix the Lagrangian of the model but leave the fermion representation completely arbitrary. It is shown that by a special choice for the fermion representation (derived from the adjoint representation ofG by an appropriate reduction) one arrives naturally at the supersymmetric non-linear model onM=G/H. The issue of quantum integrability is also discussed, though with less stringent results.Work partially supported by CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), Brazil, and KFA Jülich, Federal Republic of GermanyOn leave of absence from Fakultät für Physik der Universität Freiburg, Federal Republic of Germany     

Note on the application of the reduced graph model in conjunction with search trees to the enumeration ofKekulé structures

The reduced graph model, when used in conjunction with the search trees method, provides a novel combinatorial procedure for the enumeration and generation ofKekulé structures. The procedure is suited for large benzenoid hydrocarbons consisting of cata- and thin peri-condensed parts.

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Zur Anwendung des Reduced Graph Model im Zusammenhang mit Search Trees zur Ermittlung der Anzahl möglicherKekulé-Strukturen

Zusammenfassung Das Modell erlaubt mit der im Titel genannten Kombination eine neuartige Methode zur Ermittlung und Generierung vonKekulé-Strukturen. Das Verfahren ist für große benzoide Kohlenwasserstoffe geeignet, die aus cata- und (dünnen) peri-kondensierten Teilstrukturen bestehen.

     

Combinatorial Clar sextet theory

Clar structures recently used as basis-set to compute resonance energies [9] are identified as maximal independent sets of benzenoid hydrocarbons colored in a special way. Binomial properties of such objects are induced for several catafusenes and perifusenes (Eqs. 2–31). Novel polynomials, called Clar polynomials, are given for perifusens in terms of units of catafusenes which allow display and enumeration of the populations of their Clar structures. The work is particularly pertinent to that of [8] and [9].This paper is dedicated to Professor Eric Clar; the Doyen of aromatic chemistry.     

Viscoelasticity,mechanical properties,and in vivo biocompatibility of injectable polyvinyl alcohol/bioactive glass composite hydrogels as potential bone tissue scaffolds

Abstract

An injectable composite hydrogel composed of polyvinyl alcohol (PVA) and bioactive glass (BG) particles were synthesized by a physical crosslinking approach. The morphology, mechanical properties, and viscoelasticity of the PVA/BG composite hydrogel were characterized. Scanning electronic microscopy (SEM) showed uniform and homogeneous distribution of BG particles throughout the composite hydrogel. The incorporation of 2.5?wt% of BG particles in the composite hydrogel formulations, enhanced the static compressive strength and static elastic modulus by 325% and 150%, respectively. The storage molds (G′) was greater than the loss modules (G′′) at all the frequency range studied, which revealed a self-standing elastic composite hydrogel with a smooth injectability. The PVA/BG composite hydrogel was also implanted subcutaneously in the dorsal region of adult male rats. After 4?weeks of implantation, no inflammatory cells were seen within and around the implant, which indicated that the composite hydrogel was biocompatible. The properties of the synthesized injectable PVA/BG composite hydrogel demonstrate its capability toward bone regeneration.     

Extraction of tungsten and rhenium by basic or neutral extractants in xylene from mineral acidic media

Extraction of WO ₄ ^2– and ReO ₄ ^– by Adogen-381, tricaprylmethylammonium chloride, Hyamine 10-X, trioctylphosphine oxide or dibenzylsulphoxide in xylene from HNO₃, HCl or H₂SO₄ acid medium was investigated. Based on the separation factors obtained, the separation of ReO ₄ ^– from WO ₄ ^2– was elucidated. ReO ₄ ^– was separated from WO ₄ ^2– in high radiochemical purity: >99.9% by three successive extractions and strippings using Adogen-381 from HCl or HNO₃ acid medium.