63 research outputs found
PtRu nanoparticles supported on noble carbons for ethanol electrooxidation
In this work, three cytosine derived nitrogen doped carbonaceous materials (noble carbons, NCs) with different atomic C/N ratios and porous networks have been synthesized and used as supports for PtRu electrocatalysts in the ethanol oxidation reaction (EOR) for clean hydrogen production. Both, the metal phase and the carbon support play critical roles in the electrocatalysts final performance. Lower NPs size distribution was obtained over supports with low atomic C/N ratios (i.e., 4 and 6) and defined porosity (i.e., 1701 m2 g−1 for PtRu/CNZ and 1834 m2 g−1 for PtRu/CLZ, respectively). In contrast, a lower C/N ratio and poor porous network (i.e., 65 m2 g−1, PtRu/CLK) led to the largest particle size and fostered an increase of the alloying degree between Pt and Ru NPs (i.e., 3 for C/N ~ 6 and 28 for C/N ~ 3). Electrochemical active surface area was found to increase with decreasing NPs size and the alloy extent, due to a higher availability of Pt active sites. Accelerated degradation tests showed that PtRu/NCs outperform similar to PtRu NPs on commercial carbon pointing at the stabilizing effect of NCs. PtRu/CNZ exhibited the best electrochemical performance (i.e., 69.1 mA mgPt−1), outperforming PtRu/CLZ and PtRu/CLK by 3- and 9-fold, respectively, due to a suitable compromise between particle sizes, degree of alloy, textural properties and elemental composition. Best anodes were scaled-up to a proton exchange membrane cell and PtRu/CNZ was proved to provide the best electrocatalytic activity (262 mA cm−2 and low energy requirements), matching the values obtained by the state of the art of EOR electrocatalysts
Monoamine oxidase A (MAOA) interaction with parenting practices on callous-unemotional traits in preschoolers
Background and Objectives: From a gene-by-environment perspective, parenting in interaction with the polymorphism in the Monoamine oxidase A (MAOA) gene (MAOA-uVNTR) might also be associated with increased callous-unemotional traits (CU) in preschoolers. MAOA-uVNTR results in differential enzyme activity, so that high-activity alleles (MAOA-H) are linked to reduced dopamine, serotonin, and norepinephrine availability in comparison to low-activity allele (MAOA-L). As MAOA-uVNTR has been previously described to moderate the relationship between childhood parental maltreatment and aggressive and antisocial behavior, it may also play a role in CU traits etiology
Irritability and parenting practices as mediational variables between temperament and affective, anxiety, and oppositional defiant problems
Irritability and parenting are potential targets for transdiagnostic studies to identify the common and core dysfunctional characteristics underlying several diagnostic pictures with the goal of addressing these issues in treatment. Our objective was to investigate the different paths from temperament to child psychopathology (affective, anxiety, and oppositional problems) through irritability and parenting using a prospective design from ages 3 to 7. A sample of 614 3-year-old preschoolers was followed at ages 4, 6, and 7. Parents answered questionnaires about temperament (age 3), irritability (age 4), parenting practices (age 6), and psychopathology (age 7). Statistical analyses were carried out through structural equation modeling (SEM) to test the mediation effect of irritability and parenting practices from temperament (negative affectivity and effortful control) through to affective, anxious, and oppositional problems. The proposed model fit the data well. SEM showed (a) an indirect effect from temperament to affective problems, via irritability and positive parenting; (b) a direct effect from negative affectivity to anxiety, plus an indirect effect from both temperament dimensions, via irritability and autonomy parenting practices; and (c) an indirect effect from temperament to oppositional problems, via irritability and punitive parenting. Irritability and parenting are transdiagnostic mediational variables that should be focused on in intervention programs for affective, anxiety, and oppositional problem
Impacto de la formación en el manejo de la patologÃa locomotriz axial atraumática en la actividad asistencial del médico interno residente
El objetivo del presente estudio es el determinar el efecto de la aplicación de un programa formativo para médicos internos residentes sobre manejo de patologÃa atraumática axial en un entorno de medicina de urgencias.El programa formativo consiste en la aplicación de una jornada de charlas magistrales de 4 horas lectivas que se imparten a lo largo del año a residentes que van a empezar su segundo año de programa de especialización y que realizan actividad en el servicio de urgencias.El estudio consistió en valorar la aplicación de los conocimientos impartidos en la labor asistencial durante las jornadas de atención continuada (guardias de puerta) en términos de necesidad de reevaluaciones por urgencias, uso de pruebas complementarias y necesidad de hospitalización por mal control analgésico.La cifra de solicitud de pruebas radiológicas complementarias se redujo significativamente después de la ejecución del curso optativo sin embargo en los siguientes meses la cifra retornó a su valor inicial. El asistir al curso no modificó significativamente el tiempo hasta que los pacientes volvieron a consultar por el mismo motivo aunque se evidenció una tendencia a la prolongación de este en pacientes atendidos por residentes que hicieron el curso. La especialidad de procedencia de los MIRes fue la variable que más influyó en la curva de supervivencia.Concluimos que el impacto de la formación en el manejo de la patologÃa axial depende de los cursos impartidos y del interés que estos generen en los MIRes
Rhodium nanoparticles for ultraviolet plasmonics
The nonoxidizing catalytic noble metal rhodium is introduced for ultraviolet plasmonics. Planar tripods of 8 nm Rh nanoparticles, synthesized by a modified polyol reduction method, have a calculated local surface plasmon resonance near 330 nm. By attaching p-aminothiophenol, local field-enhanced Raman spectra and accelerated photodamage were observed under near-resonant ultraviolet illumination, while charge transfer simultaneously increased fluorescence for up to 13 min. The combined local field enhancement and charge transfer demonstrate essential steps toward plasmonically enhanced ultraviolet photocatalysis.This work has
been supported by NSF-ECCS-12-32239. This work was
partially supported by the Army’s In-house Laboratory
Innovative Research program. Financial support from USAITCA
(project no. W911NF-13-1-0245) and MICINN (Spanish
Ministry of Science and Innovation, project no. FIS2013-
45854-P) is also acknowledged
International comparisons of behavioral and emotional problems in preschool children: parents’ reports from 24 societies
International comparisons were conducted of preschool children’s behavioral and
emotional problems as reported on the Child Behavior Checklist for Ages 1½–5 by parents
in 24 societies (N¼19,850). Item ratings were aggregated into scores on syndromes; Diagnostic
and Statistical Manual of Mental Disorders–oriented scales; a Stress Problems scale;
and Internalizing, Externalizing, and Total Problems scales. Effect sizes for scale score differences
among the 24 societies ranged from small to medium (3–12%). Although societies
differed greatly in language, culture, and other characteristics, Total Problems scores for
18 of the 24 societies were within 7.1 points of the omnicultural mean of 33.3 (on a scale of
0–198). Gender and age differences, as well as gender and age interactions with society,
were all very small (effect sizes<1%). Across all pairs of societies, correlations between
mean item ratings averaged .78, and correlations between internal consistency alphas
for the scales averaged .92, indicating that the rank orders of mean item ratings and internal
consistencies of scales were very similar across diverse societies
Anti-tumour necrosis factor discontinuation in inflammatory bowel disease patients in remission: study protocol of a prospective, multicentre, randomized clinical trial
Background:
Patients with inflammatory bowel disease who achieve remission with anti-tumour necrosis factor (anti-TNF) drugs may have treatment withdrawn due to safety concerns and cost considerations, but there is a lack of prospective, controlled data investigating this strategy. The primary study aim is to compare the rates of clinical remission at 1?year in patients who discontinue anti-TNF treatment versus those who continue treatment.
Methods:
This is an ongoing, prospective, double-blind, multicentre, randomized, placebo-controlled study in patients with Crohn?s disease or ulcerative colitis who have achieved clinical remission for ?6?months with an anti-TNF treatment and an immunosuppressant. Patients are being randomized 1:1 to discontinue anti-TNF therapy or continue therapy. Randomization stratifies patients by the type of inflammatory bowel disease and drug (infliximab versus adalimumab) at study inclusion. The primary endpoint of the study is sustained clinical remission at 1?year. Other endpoints include endoscopic and radiological activity, patient-reported outcomes (quality of life, work productivity), safety and predictive factors for relapse. The required sample size is 194 patients. In addition to the main analysis (discontinuation versus continuation), subanalyses will include stratification by type of inflammatory bowel disease, phenotype and previous treatment. Biological samples will be obtained to identify factors predictive of relapse after treatment withdrawal.
Results:
Enrolment began in 2016, and the study is expected to end in 2020.
Conclusions:
This study will contribute prospective, controlled data on outcomes and predictors of relapse in patients with inflammatory bowel disease after withdrawal of anti-TNF agents following achievement of clinical remission.
Clinical trial reference number:
EudraCT 2015-001410-1
Light guiding and switching using eccentric core-shell geometries
High Refractive Index (HRI) dielectric nanoparticles have been proposed as an alternative to metallic ones due to their low absorption and magnetodielectric response in the VIS and NIR ranges. For the latter, important scattering directionality effects can be obtained. Also, systems constituted by dimers of HRI dielectric nanoparticles have shown to produce switching effects by playing with the polarization, frequency or intensity of the incident radiation. Here, we show that scattering directionality effects can be achieved with a single eccentric metallo-HRI dielectric core-shell nanoparticle. As an example, the effect of the metallic core displacements for a single Ag-Si core-shell nanoparticle has been analyzed. We report rotation of the main scattering lobe either clockwise or counterclockwise depending on the polarization of the incident radiation leading to new scattering configurations for switching purposes. Also, the efficiency of the scattering directionality can be enhanced. Finally, chains of these scattering units have shown good radiation guiding effects, and for 1D periodic arrays, redirection of diffracted intensity can be observed as a consequence of blazing effects. The proposed scattering units constitute new blocks for building systems for optical communications, solar energy harvesting devices and light guiding at the nanoscale level.This research was supported by MICINN (Spanish Ministry of Science and Innovation, project FIS2013-45854-P) and Fundación Iberdrola Espan~a, Call for Research on Energy and the Environment Grants. Á.I.B. and Y.G. want to express her gratitude to the University of Cantabria for their PhD grants
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