Graphite Electrode Modified with a New Phenothiazine Derivative and with Carbon Nanotubes for NADH Electrocatalytic Oxidation

The electrochemical behavior of a modified electrode obtained by immobilization of single-walled carbon nanotubes onto a graphite electrode modified with a new phenothiazine derivative, bis-phenothiazin-3-yl methane (BPhM), G/BPhM-CNT, has been evaluated and compared with BPhM adsorbed on graphite electrode (G/BPhM). The G/BPhM-CNT electrode presents improved performances for NADH electrocatalytic oxidation in comparison with G/BPhM electrode, expressed by: (i) a significant increase of electrocatalytic rate constant (kobs,[NADH] 0) for NADH oxidation (856.32 L mol–1 s–1 for G/BPhM-CNT and 51.63 L mol–1 s–1 for G/BPhM, in phosphate buffer, pH 7); (ii) the obtained amperometric sensors for NADH detection present increase sensitivity (S = 6.9 mA L mol–1 for G/BPhM-CNT and S = 0.55 mA L mol–1 for G/BPhM, pH 7)

Corrosion Behavior of Composite Coatings Obtained by Electrolytic Codeposition of Copper with Al2O3 Nanoparticles

Composite coatings of copper incorporating Al2O3 nanoparticles electrodeposited on carbon steel were obtained and characterized. By using electrochemical methods such as open circuit potential (ocp) measurements, polarization curves and electrochemical impedance spectroscopy, the corrosion behavior of the Al2O3-copper nanocomposite coatings was examined. The corrosion parameters determined from the polarization curves recorded in Na2SO4 solution (pH 3) indicate that the corrosion process on copper-Al2O3 composite surface is slower than on pure copper. The impedance spectra recorded at the ocp showed in all cases an increase of the polarization resistance in time, which may be explained by the development of corrosion products on the electrode surface. Using a (2RC) equivalent electrical circuit, the process parameters were estimated by non-linear regression calculations with a Simplex method. The Al2O3 particles embedded in the electroplated copper, increase the polarization resistance and decrease the corrosion rates as compared with electrodeposited pure copper. The electrochemical results were corroborated with those obtained by SEM and EDX investigations

Traumatic brain injury patients: does frontal brain lesion influence basic emotion recognition?

Adequate emotion recognition is relevant to individuals' interpersonal communication. Patients with frontal traumatic brain injury (TBI) exhibit a lower response to facial emotional stimuli, influencing social interactions. In this sense, the main goal of the current study was to assess the ability of TBI patients in recognising basic emotions. Photographs of facial expressions of five basic emotions (happiness, sadness, fear, anger, and surprise) were presented to 32 TBI patients and 41 healthy controls. Emotion recognition was measured by accuracy and reaction time. Overall performance of the TBI group was poorer than control group for emotion recognition, both in terms of accuracy and reaction time. It is suggested that TBI patients show impairment on emotion recognition, and this relation seems to be moderated by the lesion localization

Changes in social emotion recognition following traumatic frontal lobe injury

WOS:000299915100004Changes in social and emotional behaviour have been consistently observed in patients with traumatic brain injury. These changes are associated with emotion recognition deficits which represent one of the major barriers to a successful familiar and social reintegration. In the present study, 32 patients with traumatic brain injury, involving the frontal lobe, and 41 age- and education-matched healthy controls were analyzed. A Go/No-Go task was designed, where each participant had to recognize faces representing three social emotions (arrogance, guilt and jealousy). Results suggested that ability to recognize two social emotions (arrogance and jealousy) was significantly reduced in patients with traumatic brain injury, indicating frontal lesion can reduce emotion recognition ability. In addition, the analysis of the results for hemispheric lesion location (right, left or bilateral) suggested the bilateral lesion sub-group showed a lower accuracy on all social emotions

Self-organising aggregates of zebrafish retinal cells for investigating mechanisms of neural lamination

To investigate the cell-cell interactions necessary for the formation of retinal layers, we cultured dissociated zebrafish retinal progenitors in agarose microwells. Within these wells, the cells re-aggregated within hours, forming tight retinal organoids. Using a Spectrum of Fates zebrafish line, in which all different types of retinal neurons show distinct fluorescent spectra, we found that by 48 h in culture, the retinal organoids acquire a distinct spatial organisation, i.e. they became coarsely but clearly laminated. Retinal pigment epithelium cells were in the centre, photoreceptors and bipolar cells were next most central and amacrine cells and retinal ganglion cells were on the outside. Image analysis allowed us to derive quantitative measures of lamination, which we then used to find that Müller glia, but not RPE cells, are essential for this process.This work was funded by a Wellcome Trust Senior Investigator Award to W.A.H. (100329/Z/12/Z) and a Biotechnology and Biological Sciences Research Council Studentship Award to M.K.E. (BB/J014540/1)

Overview of ¹⁴C release from irradiated zircaloys in geological disposal conditions

Carbon-14 (radiocarbon, 14C) is a long-lived radionuclide (5730 yr) of interest regarding the safety for the management of intermediate level wastes (ILW). The present study gives an overview of the release of 14C from irradiated Zircaloy cladding in alkaline media. 14C is found either in the alloy part of Zircaloy cladding due to the neutron activation of 14N impurities by 14N(n,p)14C reaction, or in the oxide layer (ZrO2) formed at the metal surface by the neutron activation of 17O from UO2 or (U-Pu)O2 fuel and water from the primary circuit in the reactor by 17O(n,α)14C reaction. Various irradiated and unirradiated Zircaloys have been studied. The total 14C inventory has been determined both experimentally and by calculations. The results seem to be in good agreement. Leaching experiments were conducted in alkaline media for several time durations. 14C was mainly released as carboxylic acids. Further, corrosion measurements were performed by using both hydrogen measurements and electrochemical measurements. The corrosion rate (CR) ranges from a few nm/yr to 100 nm/yr depending on the surface conditions and the method used for measurement. From a safety assessment point of view, the instant release fraction (IRF) was determined on irradiated Zircaloy-2. The results showed that the 14C inventory in the oxide was significantly below the 20% commonly used in safety case assessments