3D-Ensembles of gold nanowires: preparation, characterization and electroanalytical prospects

Nanoelectrode ensembles (NEEs) of gold nanodisks, prepared by electroless template deposition of gold within the pores of track-etched polycarbonate membranes, are treated with oxygen plasma or with solvent mixtures in order to achieve controlled etching of part of the polycarbonate of the template. This causes the structure of the final ensemble to change from a 2-D flat structure into a 3-D one. The cyclic voltammetric (CV) behavior of redox probes at the 3DNEEs is examined and compared with the behavior observed at 2D-NEEs. Finally, 3D-NEEs are examined in order to test possible applications for the development of mediated sensors

Corrosion inhibition effect of non-toxic -amino acid compound on high carbon steel in low molar concentration of hydrochloric acid

Electrochemical studies of the corrosion inhibition effect of biodegradable 2-amino-4- methylpentanoic acid (LCN) on high carbon steel in 1 M HCl acid was evaluated with potentiodynamic polarization technique, weight loss analysis and optical microscopy. Results show the compound to be highly effective with optimal inhibition efficiencies of 87.46% and 85.88% from the electrochemical test with dominant cathodic inhibition behaviour between 0% and 1.88% inhibitor concentration and anodic inhibition behaviour at 2.81% and 5.63% inhibitor concentration due to changes in the effect of lateral repulsion between inhibitor molecules. Thermodynamic calculations showed chemisorption molecular interaction and adsorption onto HCS surface according to Langmuir, Freundlich and Frumkin isotherm models with correlation coefficients of 0.9991, 0.8727 and 0.9782. Statistical analysis showed inhibitor concentration is only relevant variable responsible for inhibition efficiency. Calculated results from predicted corrosion rate values varied at an average value of 53% from experimental results. Optical microscopy images of LCN inhibited and uninhibited HCS samples significantly contrast each

Functionalized ensembles of nanoelectrodes as affinity biosensors for DNA hybridization detection

A novel electrochemical biosensor for DNA hybridization detection based on nanoelectrode ensembles (NEEs) is presented. NEEs are prepared by electroless deposition of gold into the pores of a templating track-etched polycarbonate (PC) membrane. The wide surface of the templating membrane surrounding the nanoelectrodes is exploited to bind the capture DNA probes via amide coupling with the carboxylic groups present on the PC surface. The probes are then hybridized with the complementary target labelled with glucose oxidase (GO). The occurrence of the hybridization event is detected by adding, to the supporting electrolyte, excess glucose as the substrate and the (ferrocenylmethyl) trimethylammonium cation (FA) as suitable redox mediator. In the case of positive hybridization, an electrocatalytic current is detected. In the proposed sensor, the biorecognition event and signal transduction occur in different but neighbouring sites, i.e., the PC surface and the nanoelectrodes, respectively; these sites are separated albeit in close proximity on a nanometer scale. Finally, the possibility to activate the PC surface by treatment with permanganate is demonstrated and the analytical performances of biosensors prepared with KMnO4-treated NEEs and native NEEs are compared and critically evaluated. The proposed biosensor displays high selectivity and sensitivity, with the capability to detect few picomoles of target DNA

Mänskliga rättigheter - hur redovisas de?

Globaliseringen har bidragit till nya möjligheter men också hot för företag. Västvärldens företag kan lägga produktionen i delar av världen där kostnaden för att tillverka en vara är lägre än i hemlandet. I dessa leverantörsled kan missförhållanden uppstå såsom kränkningar av mänskliga rättigheter. Intressenter av olika slag fordrar mer transparens av företagen, det vill säga de kräver information utöver den finansiella i företagens rapporter. Hållbarhetsredovisning är en form av redovisning som har blivit allt vanligare och anses generellt innehålla information om företagets ekonomiska, miljömässiga och sociala prestanda. I jämförelse med den finansiella redovisningen existerar det ännu inga standarder för denna form av rapportering. Global Reporting Initiative är en internationellt erkänd organisation som arbetar för att utforma riktlinjer för hållbarhetsrapportering, vilka är frivilliga att upprätta. Hållbarhetsredovisningen visar på att redovisningen går mot en ny era där det inte endast räcker med finansiell redovisning utan företagen bör ta ett större ansvar gentemot samhället och miljön. Syftet med denna uppsats är att undersöka hur företag mäter och redovisar mänskliga rättigheter. En kvalitativ metod har använts för att genomföra studien, där fem företags hållbarhetsredovisningar har undersökts. Teorin som ligger till grund för undersökningen är de informationskvalitativa egenskaperna, vilka genomsyrar den finansiella redovisningen. Slutsatserna visar att fallföretagen inte mäter mänskliga rättigheter på arbetsplatsen i kvantitativa termer. Däremot redovisar de mänskliga rättigheter i form av kvalitativ information. Av studien framkom även att informationen i de undersökta hållbarhetsredovisningarna är begriplig, att uppförandekoder är en del av relevansen, att granskningen ökar tillförlitligheten och att jämförbarheten blir relativt god tack vare GRI: s riktlinjer och dess innehållsförteckning

Effects of Interruption in Power Supply of Induction Motors in Isolated Electrical Grid

The aim of this paper is to analyse effects of power supply interruption on dynamics of induction motors connected to a synchronous generator in an autonomous operation. A complex mathematical model has been developed, whose components are: a diesel engine, a synchronous generator, a mechanical connection, and two unregulated induction motors which are fed directly from the synchronous generator terminals

Considerações sobre o movimento curricular no contexto da educação infantil

Este trabalho discute a complexidade da evolução histórica da educação de crianças de 0 a 6 anos e as concepções de infância, de educação, de ação docente e de currículo veiculadas explícita ou tacitamente nesses paradigmas. A reflexão sobre as políticas públicas para educação infantil e formação de professores torna- se fundamental para que possamos, a partir do quadro histórico apresentado, oferecer possibilidades alternativas para a estruturação de uma proposta curricular voltada ao contexto sócio-cultural dos envolvidos no processo educativo