Highly Active W2C-Based Composites for the HER in Alkaline Solution: the Role of Surface Oxide Species.

The hydrogen evolution reaction (HER) is a crucial electrochemical process for the proposed hydrogen economy since it has the potential to provide pure hydrogen for fuel cells. Nowadays, hydrogen electroproduction is considerably expensive, so promoting the development of new non-noble catalysts for the cathode of alkaline electrolyzers appears as a suitable way to reduce the costs of this technology. In this sense, a series of tungsten-based carbide materials have been synthesized by the urea-glass route as candidates to improve the HER in alkaline media. Moreover, two different pyridinium-based ionic liquids were employed to modify the surface of the carbide grains and control the amount and nature of their surface species. The main results indicate that the catalyst surface composition is modified in the hybrid materials, which are then distinguished by the appearance of tungsten suboxide structures. This implies the action of ionic liquids as reducing agents. Consequently, differential electrochemical mass spectrometry (DEMS) is used to precisely determine the onset potentials and rate-determining steps (RDS) for the HER in alkaline media. Remarkably, the modified surfaces show high catalytic performance (overpotentials between 45 and 60 mV) and RDS changes from Heyrovsky-Volmer to Heyrovsky as the surface oxide structures get reduced. H2O molecule reduction is then faster at tungsten suboxide, which allows the formation of the adsorbed hydrogen at the surface, boosting the catalytic activity and the kinetics of the alkaline HER.

A randomized trial of teaching clinical skills using virtual and live standardized patients.

BACKGROUND: We developed computer-based virtual patient (VP) cases to complement an interactive continuing medical education (CME) course that emphasizes skills practice using standardized patients (SP). Virtual patient simulations have the significant advantages of requiring fewer personnel and resources, being accessible at any time, and being highly standardized. Little is known about the educational effectiveness of these new resources. We conducted a randomized trial to assess the educational effectiveness of VPs and SPs in teaching clinical skills. OBJECTIVE: To determine the effectiveness of VP cases when compared with live SP cases in improving clinical skills and knowledge. DESIGN: Randomized trial. PARTICIPANTS: Fifty-five health care providers (registered nurses 45%, physicians 15%, other provider types 40%) who attended a CME program. INTERVENTIONS: Participants were randomized to receive either 4 live cases (n=32) or 2 live and 2 virtual cases (n=23). Other aspects of the course were identical for both groups. RESULTS: Participants in both groups were equivalent with respect to pre-post workshop improvement in comfort level (P=.66) and preparedness to respond (P=.61), to screen (P=.79), and to care (P=.055) for patients using the skills taught. There was no difference in subjective ratings of effectiveness of the VPs and SPs by participants who experienced both (P=.79). Improvement in diagnostic abilities were equivalent in groups who experienced cases either live or virtually. CONCLUSIONS: Improvements in performance and diagnostic ability were equivalent between the groups and participants rated VP and SP cases equally. Including well-designed VPs has a potentially powerful and efficient place in clinical skills training for practicing health care workers.

Early predictors of neurodevelopmental outcome in symptomatic congenital cytomegalovirus infection.

OBJECTIVE: To determine the ability of neonatal clinical, audiologic, and computed tomography (CT) findings to predict long-term neurodevelopmental outcome in children with symptomatic congenital cytomegalovirus (CMV) infection. METHODS: Longitudinal cohort study of children (n = 41) with symptomatic congenital CMV infection evaluated at birth and followed up with serial age-appropriate neurodevelopmental testing. The performance of birth characteristics as predictors of long-term outcome were determined, and clinical and CT scoring systems were developed and correlated with intellectual outcome. RESULTS: Microcephaly was the most specific predictor of mental retardation (100%; 95% CI 84.5-100) and major motor disability (92.3%; 95% CI 74.8-99). An abnormality detected by CT was the most sensitive predictor for mental retardation (100%; 95% CI 82.3-100) and motor disability (100%; 95% CI 78.2-100). A highly significant (P <.001) positive correlation was found between head size at birth and the intelligence/developmental quotient (IQ/DQ). Approximately 29% of children had an IQ/DQ >90. There was no association between sensorineural hearing loss at birth and cognitive outcome. However, children with sensorineural hearing loss on follow-up (congenital and late-onset) had a lower IQ/DQ (P =.006) than those with normal hearing. CONCLUSIONS: The presence of microcephaly at birth was the most specific predictor of poor cognitive outcome in children with symptomatic congenital CMV infection, whereas children with normal findings on head CT and head circumference proportional to weight exhibited a good cognitive outcome.

Cytomegalovirus urinary excretion and long term outcome in children with congenital cytomegalovirus infection. Congenital CMV Longitudinal Study Group.

BACKGROUND: Cytomegalovirus (CMV) is the most frequent cause of congenital infection, and both symptomatic and asymptomatic infants may have long term sequelae. Children with congenital CMV infection are chronically infected and excrete CMV in the urine for prolonged periods. However, the effect of prolonged viral replication on the long term outcome of these children is unknown. OBJECTIVE: To determine whether duration of CMV excretion is associated with outcome at 6 years of life in symptomatic and asymptomatic congenitally infected children. METHODS: Longitudinal cohort study. Children congenitally infected with CMV were identified at birth and followed prospectively in a study of long term effects of congenital CMV infection. The relationship between duration of CMV urinary excretion and growth, neurodevelopment and presence and progression of sensorineural hearing loss (SNHL) at 6 years of age was determined. RESULTS: There was no significant difference in the duration of viral urinary excretion between children born with asymptomatic (median, 4.55 years) and symptomatic (median, 2.97 years) congenital CMV infection (P = 0.11). Furthermore there was no association between long term growth or cognitive outcome and duration of viral excretion. However, a significantly greater proportion of children who excreted CMV for <4 years had SNHL and progressive SNHL compared with children with CMV excretion >4 years (P = 0.019, P = 0.009, respectively). CONCLUSIONS: Children congenitally infected with CMV are chronically infected for years, but the duration of CMV urinary excretion is not associated with abnormalities of growth, or neurodevelopmental deficits. However, SNHL and progressive SNHL were associated with a shorter duration of CMV excretion.