FERROCENYL ALKYLAMMONIUM N-SUBSTITUTED POLYPYRROLE CONTAINING Pt AND Pd AND ITS APPLICATION ON ELECTROANALYSIS OF ARSENITE

Indexación: Web of Science; Scopus; Scielo.Arsenic occurs in a variety of forms and oxidation states and is a very toxic element. The main inorganic arsenic species present in natural waters are arsenate (oxidation state V) and arsenite ions (oxidation state III). Arsenite is more toxic and mobile than arsenate. Therefore, it is important the development of new materials for analysis and control of these toxic species. This research proves that polymer-metal composite electrode materials synthesized by incorporation of Pt-0 and Pd-0 nanoparticles into a poly(pyrrole-ferrocenyl alkylammonium) matrix present electrocatalytic properties towards the oxidation of arsenite to arsenate. The polymer films displayed a stable electrochemical response in aqueous solution. However, when the polymer film modified electrode were transferred to aqueous solution in presence of arsenite anions, the CV curves for polymer films were deeply modified by the decrease in the electroactivity of the film. It can be concluded that the cationic polymer films present a strong affinity toward arsenite anions. The composite films containing Pt-0 or Pd-0 showed catalytic activity towards oxidation of As(III) to As(V) due to the presence of metal catalyst particles into the polymer films.http://ref.scielo.org/dgdvx

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

The embryo as moral work object: PGD/IVF staff views and experiences

Copyright @ 2008 the authors. This article is available in accordance with the Creative Commons Deed, Attribution 2.5, see http://creativecommons.org/licenses/by-nc-nd/2.5/deed.en_CA.We report on one aspect of a study that explored the views and experiences of practitioners and scientists on social, ethical and clinical dilemmas encountered when working in the field of preimplantation genetic diagnosis (PGD) for serious genetic disorders. The study produced an ethnography based on observation, interviews and ethics discussion groups with staff from two PGD/IVF Units in the UK. We focus here on staff perceptions of work with embryos that entails disposing of ‘affected’ or ‘spare’ embryos or using them for research. A variety of views were expressed on the ‘embryo question’ in contrast to polarised media debates. We argue that the prevailing policy acceptance of destroying affected embryos, and allowing research on embryos up to 14 days leaves some staff with rarely reported, ambivalent feelings. Staff views are under-researched in this area and we focus on how they may reconcile their personal moral views with the ethical framework in their field. Staff construct embryos in a variety of ways as ‘moral work objects’. This allows them to shift attention between micro-level and overarching institutional work goals, building on Casper's concept of ‘work objects’ and focusing on negotiation of the social order in a morally contested field.The Wellcome Trust Biomedical Ethics Programme, who funded the projects‘Facilitating choice, framing choice: the experience of staff working in pre-implantation genetic diagnosis’ (no: 074935), and ‘Ethical Frameworks for Embryo Donation:the views and practices of IVF/PGD staff’ (no: 081414)

Nano-finishing of cellulose textile materials with copper and copper oxide nanoparticles

Nano-finishing of textile materials with metal and metal oxide nanoparticles has been in the focus of science and textile industry almost two decades. The emergence of bacteria resistance to silver nanoparticles due to over-use, cheaper precursor salts and excellent antimicrobial activity recently brought copper and copper oxide nanoparticles to scientific attention particularly for the utilization in the field of medical textiles. This paper is aimed to give an overview of the latest achievements in the finishing of cellulose fabrics with copper-based nanoparticles. Special emphasis has been given to difficulties met throughout the characterization of such textile nanocomposites caused by the copper instability. In addition the effect of various chemical modifications of cellulose fibers prior to impregnation with copper-based nanoparticles on their binding efficiency was considered. Much attention has been also paid to antimicrobial activity of such textile nanocomposites and the possibility to develop efficient antimicrobial cellulose wound dressings. [GRAPHICS]