A novel effect. Changes in the electrochemical response of polycrystalline platinum promoted by very fast potential perturbations

It is well established that the voltammogram of polycrystalline platinum in acid electrolyte in the potential range corresponding to the stability of bulk water depends on the electrode history including the type of perturbation applied to the electrode and on the electrolyte composition.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

A novel effect. Changes in the electrochemical response of polycrystalline platinum promoted by very fast potential perturbations

It is well established that the voltammogram of polycrystalline platinum in acid electrolyte in the potential range corresponding to the stability of bulk water depends on the electrode history including the type of perturbation applied to the electrode and on the electrolyte composition.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

Parvovirus B19: Insights and implication for pathogenesis, prevention and therapy

Parvovirus B19 (B19V) is a small ssDNA non-enveloped virus, member of Parvoviridae family. The infection is widely diffused and is responsible for a broad range of clinical manifestations including fifth disease in children, transient aplastic crisis in patients with haematological disorders, non-immune hydrops fetalis in pregnant women, persistent anaemia in immunocompromised patients, arthropathy and inflammation of various other tissues. B19V infects and replicates in erythroid progenitor cells (EPCs) in the bone marrow. The depletion of infected EPCs represents the pathogenetic mechanisms of some haematological B19V-associate diseases. Following a primary infection, the virus can establish lifelong persistence in several tissues. Currently, the pathological potential of persistent virus on the cellular signalling pathways remains unclear. In non-erythroid tissues, the infection is usually, abortive, and the virus seems to exert its pathological role through indirect mechanisms, such as induction of inflammatory and autoimmune processes, or through virus-induced apoptosis mediated by viral proteins. In addition to the diseases for which the etiological role of B19V has been fully demonstrated, there are several clinical conditions, including autoimmune diseases, that are presumably, but not certainly, associated with B19V infection. In this review, we describe recent findings that may give us new insight into the pathogenic role of B19V in systemic sclerosis, an autoimmune disease of unknown multifactorial aetiology. Furthermore, we describe the latest findings on the intrauterine B19V infections. Moreover, since there are some ongoing interesting studies focused on vaccine development and antiviral drug discovery for the prevention and treatment of parvovirus B19 infection we described some advances in this field of research

Potentiodynamic current/potential characteristics of theoretical mechanisms related to the electrochemical formation and electroreduction of monolayer films on inert electrodes

The current/potential curves of various mechanisms related to the electrochemical formation and electroreduction of monolayer films on inert electrodes, involving a single surface covering species and two surface covering species are presented. The potential perturbation functions consist both of single either linear or triangular potential sweeps and of triangular modulated linear potential sweeps. A comparison of the theoretical Eli displays obtained with the different potential perturbation techniques is given for the various reaction pathways presented.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Modulated reflectance spectroscopy and voltammetry of the sulphide/gold system

The electroadsorption of sulphide species on gold and the growth of sulphur multilayers have been investigated by optical and electrochemical techniques in sodium tetraborate buffer as the supporting electrolyte (pH 7.0 and 9.2) at 25°C. Differential reflectance spectra indicate that the adsorption of sulphide begins inside the hydrogen evolution reaction (HER) region. The HER is catalysed by the presence of sulphide species on the electrode. During the growth of sulphur multilayers, soluble polysulphide species can be optically detected either as intermediates under diffusion-controlled kinetics or as products of a chemical reaction between sulphide ions and the deposited sulphur layer. The steep fall in the integral reflectance at 0.4 V (vs. SHE) is interpreted through the incorporation of light-absorbing polysulphides into the structure of the deposited sulphur layer.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

The electrooxidation of chemisorbed co on polycrystalline platinum: A mechanistic interpretation of the anodic current peak multiplicity

The electrooxidation of CO on polycrystalline Pt in 1 M HClO4 at 23°C under potentiodynamic conditions exhibits a double current peak. Whether a single or a double current peak is formed depends to a great extent on the amount of CO surface coverage. The present report attempts to explain the behaviour of the electrochemical reaction in terms of a single model involving the participation of two CO adsorbed states on polycrystalline Pt.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

Modulated reflectance spectroscopy and voltammetry of the sulphide/gold system

The electroadsorption of sulphide species on gold and the growth of sulphur multilayers have been investigated by optical and electrochemical techniques in sodium tetraborate buffer as the supporting electrolyte (pH 7.0 and 9.2) at 25°C. Differential reflectance spectra indicate that the adsorption of sulphide begins inside the hydrogen evolution reaction (HER) region. The HER is catalysed by the presence of sulphide species on the electrode. During the growth of sulphur multilayers, soluble polysulphide species can be optically detected either as intermediates under diffusion-controlled kinetics or as products of a chemical reaction between sulphide ions and the deposited sulphur layer. The steep fall in the integral reflectance at 0.4 V (vs. SHE) is interpreted through the incorporation of light-absorbing polysulphides into the structure of the deposited sulphur layer.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

The electrooxidation of CO: a test reaction in electrocatalysis

This review paper aims to show how the electrochemical behaviour of CO plays a key role in the understanding of the reaction mechanism of many electrocatalytic oxidations of small organic molecules. For that purpose, the adsorption of CO on noble metal electrodes, eventually modified by foreign metal adatoms, is reviewed, taking into account both experimental (electrochemical and spectroscopic techniques) and theoretical (Extended Hückel Model) approaches. Data from the gas phase-solid metal interface are also considered.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

The electrooxidation of CO: a test reaction in electrocatalysis

This review paper aims to show how the electrochemical behaviour of CO plays a key role in the understanding of the reaction mechanism of many electrocatalytic oxidations of small organic molecules. For that purpose, the adsorption of CO on noble metal electrodes, eventually modified by foreign metal adatoms, is reviewed, taking into account both experimental (electrochemical and spectroscopic techniques) and theoretical (Extended Hückel Model) approaches. Data from the gas phase-solid metal interface are also considered.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta