Electrochemical characterisation of gold on Pt{h k l} for ethanol electrocatalysis

The cyclic voltammetric (CV) behaviour of gold adsorbed on Pt{h k l} electrodes is reported. It is found that stepped surfaces vicinal to Pt{1 1 1} exhibit preferential adsorption of gold at step sites. However, for stepped surfaces containing Pt{1 0 0} terraces, adsorption of gold at step and terrace site occurs with equal probability, although for Pt{n 1 1} electrodes with n < 7 (i.e. electrodes containing short Pt{1 0 0} terraces), slight preference for step site adsorption is still observed. This behaviour is similar to that reported previously for Bi adsorption on Pt{h k l} and is interpreted in terms of slower rates of gold atom surface diffusion across Pt{1 0 0} vs. Pt{1 1 1} terraces. By comparing the electrochemical response of gold adlayers on Pt{h k l} with previously published bulk Au{h k l} voltammetry, it is deduced that the gold overlayers on Pt{h k l} are pseudomorphic in nature. This finding is in agreement with previous UHV and electrochemical results for gold deposition on platinum. Using such gold modified Pt{h k l} electrodes as model surfaces, we also report, for the first time, the electrooxidation of ethanol on Au/Pt{h k l} in alkaline aqueous solution. The ethanol oxidation reaction (EOR) is shown to be structure sensitive for submonolayer gold coverages. In fact, a maximum in the rate of EOR at platinum sites adjacent to gold islands is observed between approximately 0.4–0.6 monolayers of gold on Pt{1 0 0}, Pt{1 1 1} and Pt{1 1 0} in 0.1 M NaOH(aq). A second electrooxidation state at more positive potentials for 0 < θ_Au < 1 ascribed to EOR at pure gold sites is also observed, at least for Pt{1 1 1} and Pt{1 0 0}. On Pt{1 1 1}, the potential range and activity of EOR in this second process is similar to bulk gold whereas for submonolayer gold films on Pt{1 0 0}, the peak is shifted to more negative potentials.     

Comparison of the impact of atrial fibrillation on the risk of early death after stroke in women versus men

BACKGROUND: Atrial fibrillation (AF) is considered a predictive factor of poor clinical outcome in patients with an ischemic stroke (IS). This study addressed whether the impact of AF on the in-hospital mortality after first ever IS is different according to the patient's gender. METHODS: We prospectively studied 1678 patients with first ever IS consecutively admitted to two University Hospitals. We recorded demographic data, vascular risk factors, and the stroke severity (NIHSS) at admission analyzing their impact on the in-hospital mortality and on the combined mortality-dependency at discharge using a Cox proportional hazards model. Two variable interactions between those factors independently related to in-hospital mortality and combined mortality-dependency at discharge were tested. RESULTS: Overall in-hospital mortality was 11.3%. Cox proportional hazards model showed that NIHSS at admission (HR: 1.178 [95% CI 1.149-1.207]), age (HR: 1.044 [95% CI 1.026-1.061]), AF (HR: 1.416 [95% CI 1.048-1.913]), male gender (HR: 1.853 [95% CI 1.323-2.192) and ischemic heart disease (HR: 1.527 [95% CI 1.063-2.192]) were independent predictors of in-hospital mortality. A significant interaction between gender and AF was found (p = 0.017). Data were stratified by gender, showing that AF was an independent predictor of poor outcome just for woman (HR: 2.183 [95% CI 1.403-3.396]; p < 0.001). The independent predictors of combined mortality-disability at discharge were NIHSS at admission (HR: 1.052 [95% CI 1.041-1.063]), age (HR: 1.011 [95% CI 1.004-1.018]), AF (HR: 1.197 [95% CI 1.031-1.390]), ischemic heart disease (HR: 1.222 [95% CI 1.004-1.488]), and smoking (HR: 1.262 [95% CI 1.033-1.541]). CONCLUSIONS: The impact of AF is different in the two genders and appears as a specific ischemic stroke predictor of in-hospital mortality just for women.     

Early maternal deprivation in rats induces gender-dependent effects on developing hippocampal and cerebellar cells

Adult animals submitted to a single prolonged episode of maternal deprivation [24 h, postnatal day 9–10] show behavioral alterations that resemble specific symptoms of schizophrenia. According to the neurodevelopmental theory, these behavioral deficits might be mediated by detrimental neurodevelopmental processes that might be associated, at least partially, with stress-induced corticosterone responses. In order to address this hypothesis, we have focused on the hippocampus and cerebellar cortex, two brain regions that show high density of glucocorticoid receptors, and analyzed possible neuronal and glial alterations by immunohistochemical techniques. To evaluate the presence of degenerated neurons we used Fluoro-Jade-C (FJ-C) staining and for the study of astrocytes we employed glial fibrillary acidic protein (GFAP). Within control animals, females showed significantly more GFAP positive cells than males and a trend towards more FJ-C positive cells. Maternal deprivation induced neuronal degeneration and astroglial changes in the hippocampus and cerebellar cortex of neonatal rats that, in general, were more marked in males. This differential effect may be attributable to a greater vulnerability of males to this kind of early environmental insult and/or to sex-dependent differences in the onset and/or progression of the effects. The present experimental procedure may be instrumental in elucidating sex-dependent mechanisms of neurodevelopmental psychiatric disorders with a basis in early environmental insults.     

Chronic fatigue syndrome and personality: A case-control study using the alternative five factor model

Neuroticism is the personality dimension most frequently associated with chronic fatigue syndrome (CFS). Most studies have also shown that CFS patients are less extraverted than non-CFS patients, but results have been inconsistent, possibly because the facets of the extraversion dimension have not been separately analyzed. This study has the following aims: to assess the personality profile of adults with CFS using the Alternative Five-Factor Model (AFFM), which considers Activity and Sociability as two separate factors of Extraversion, and to test the discriminant validity of a measure of the AFFM, the Zuckerman–Kuhlman Personality Questionnaire, in differentiating CFS subjects from normal-range matched controls. The CFS sample consisted of 132 consecutive patients referred for persistent fatigue or pain to the Department of Medicine of a university hospital. These were compared with 132 matched normal population controls. Significantly lower levels of Activity and significantly higher levels of Neuroticism-Anxiety best discriminated CFS patients from controls. The results are consistent with existing data on the relationship between Neuroticism and CFS, and clarify the relationship between Extraversion and CFS by providing new data on the relationship of Activity to CFS.     

Cell types and coincident synapses in the ellipsoid body of Drosophila

Cellular ultrastructures for signal integration are unknown in any nervous system. The ellipsoid body (EB) of the Drosophila brain is thought to control locomotion upon integration of various modalities of sensory signals with the animal internal status. However, the expected excitatory and inhibitory input convergence that virtually all brain centres exhibit is not yet described in the EB. Based on the EB expression domains of genetic constructs from the choline acetyl transferase (Cha), glutamic acid decarboxylase (GAD) and tyrosine hydroxylase (TH) genes, we identified a new set of neurons with the characteristic ring‐shaped morphology (R neurons) which are presumably cholinergic, in addition to the existing GABA‐expressing neurons. The R1 morphological subtype is represented in the Cha‐ and TH‐expressing classes. In addition, using transmission electron microscopy, we identified a novel type of synapse in the EB, which exhibits the precise array of two independent active zones over the same postsynaptic dendritic domain, that we named ‘agora’. This array is compatible with a coincidence detector role, and represents ~8% of all EB synapses in Drosophila. Presumably excitatory R neurons contribute to coincident synapses. Functional silencing of EB neurons by driving genetically tetanus toxin expression either reduces walking speed or alters movement orientation depending on the targeted R neuron subset, thus revealing functional specialisations in the EB for locomotion control.     

Neuroticism and impulsivity: Their hierarchical organization in the personality characterization of drug-dependent patients from a decision tree learning perspective

Objective

Neuroticism and impulsivity are the personality variables most consistently associated with drug-dependent patients. To date, no data mining procedures have been applied to explore the differential role of personality variables in this population.

Methods

The personality profile of 336 drug-dependent patients was compared with that of a sample of community participants in the context of a decision tree learning approach using the Alternative Five Factor Model. The resulting discriminant model was cross-validated.

Results

Neuroticism and impulsivity were the most relevant variables in the resulting model, but their association appeared to be hierarchically organized. In the personality characterization of these patients, neuroticism became the main discriminant dimension, whereas impulsivity played a differential role, explained by means of an interaction effect. Decision tree learning models appear to be a heuristic theoretical and empirical approximation to the study of relevant variables, such as personality traits, in drug-dependency research.     

Differences in the association between childhood trauma history and borderline personality disorder or attention deficit/hyperactivity disorder diagnoses in adulthood

European Archives of Psychiatry and Clinical Neuroscience - Common environmental etiological factors between borderline personality disorder (BPD) and attention deficit/hyperactivity disorder...