2,591 research outputs found

    Explorando la regeneración de la mordenita en la reacción de carbonilación de dimetiléter

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    Dimethyl ether carbonylation (DME) to produce methyl acetate (MA) over mordenite catalysts is attracting much attention because of its high selectivity. However, acidic mordenite suffers from a fast deactivation (coking) that has not been properly studied. In the present work, we study the regeneration of the catalyst in several cycles aiming to help the future industrial application of mordenite catalysts in MA production. Both diluted and pure air have been successfully tested for the regeneration of the catalyst. The results show that 1) there is no negative effect after several regeneration cycles and 2) there is a slight improvement of catalyst productivity after the first regeneration cycle. A possible explanation to these results, which is highlighted in this work, is that the catalyst structure is not affected during regeneration while there is an initial migration of Al from the mordenite structure to extra-framework positions.Ministerio de Economía y Competitividad, BIOTER project, Proyecto I+D Retos ENE2012-31598Ministerio de Economía y Competitividad, Universidad de Sevilla, Juan de la Cierva IJCI-2017-3283

    Microgrids Power Quality Enhancement Using Model Predictive Control

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    In electric power systems, any deviation with respect to the theoretical sinusoidal waveform is considered to be a disturbance in the power quality of the electrical grid. The deviation can alter any of the parameters of the waveform: frequency, amplitude, and symmetry among phases. Microgrid, as a part of the electric power system, has to contribute providing an adequate current waveform in grid connected-mode, as well as to guarantee similar voltage features than the standard requirement given for public distribution grids under normal exploitation conditions in islanded mode. Adequate power quality supply is necessary for the correct compatibility between all the devices connected to the same grid. In this paper, the power quality of microgrids is managed using a Model Predictive Control (MPC) methodology which regulates the power converters of the microgrids in order to achieve the requirements. The control algorithm is developed for the following microgrids working modes: grid-connected, islanded, and interconnected. The simulation results demonstrate that the proposed methodology improves the transient response in comparison with classical methods in all the working modes, minimizing the harmonic content in the current and the voltage even with the presence of non-balanced and non-harmonic-free three-phase voltage and current systems

    Ipsilesional Hippocampal GABA Is Elevated and Correlates With Cognitive Impairment and Maladaptive Neurogenesis After Cortical Stroke in Mice.

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    BACKGROUND Cognitive dysfunction is a frequent stroke sequela, but its pathogenesis and treatment remain unresolved. Involvement of aberrant hippocampal neurogenesis and maladaptive circuitry remodeling has been proposed, but their mechanisms are unknown. Our aim was to evaluate potential underlying molecular/cellular events implicated. METHODS Stroke was induced by permanent occlusion of the middle cerebral artery occlusion in 2-month-old C57BL/6 male mice. Hippocampal metabolites/neurotransmitters were analyzed longitudinally by in vivo magnetic resonance spectroscopy. Cognitive function was evaluated with the contextual fear conditioning test. Microglia, astrocytes, neuroblasts, interneurons, γ-aminobutyric acid (GABA), and c-fos were analyzed by immunofluorescence. RESULTS Approximately 50% of mice exhibited progressive post-middle cerebral artery occlusion cognitive impairment. Notably, immature hippocampal neurons in the impaired group displayed more severe aberrant phenotypes than those from the nonimpaired group. Using magnetic resonance spectroscopy, significant bilateral changes in hippocampal metabolites, such as myo-inositol or N-acetylaspartic acid, were found that correlated, respectively, with numbers of glia and immature neuroblasts in the ischemic group. Importantly, some metabolites were specifically altered in the ipsilateral hippocampus suggesting its involvement in aberrant hippocampal neurogenesis and remodeling processes. Specifically, middle cerebral artery occlusion animals with higher hippocampal GABA levels displayed worse cognitive outcome. Implication of GABA in this setting was supported by the amelioration of ischemia-induced memory deficits and aberrant hippocampal neurogenesis after blocking pharmacologically GABAergic neurotransmission, an intervention which was ineffective when neurogenesis was inhibited. These data suggest that GABA exerts its detrimental effect, at least partly, by affecting morphology and integration of newborn neurons into the hippocampal circuits. CONCLUSIONS Hippocampal GABAergic neurotransmission could be considered a novel diagnostic and therapeutic target for poststroke cognitive impairment.S

    Reliability and Validation of the Child Eating Behavior Questionnaire in 3- to 6-Year-Old Spanish Children

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    Introduction: Eating behavior is often established during the first years of life. Therefore, it is important to make a research on it to understand the relationships that children have with food and how this can contribute to prevent the development of childhood obesity. An appropriate assessment of eating behavior can be achieved using the “Child Eating Behavior Questionnaire” (CEBQ). This questionnaire has been validated in several populations and languages, but it has never been translated, adapted, and validated for Spanish children. Aim: To evaluate the reliability and internal consistency of the CEBQ questionnaire, culturally adapted and translated into Spanish (Spain), in Spanish families with children aged 3 to 6 years, as well as its association with children’s body mass index (BMI) to test its construct validity. Materials and Methods: Children between 3 and 6 years old were recruited from the ongoing MELI-POP randomized controlled clinical trial, as well as from public schools located in middle class neighborhoods of Zaragoza, Spain, to complete the sample. Sociodemographic characteristics and anthropometric measures were obtained according to standardized methods. The 35-item CEBQ questionnaire was completed twice with a time difference of 3 weeks between each response. Statistical analyses included the evaluation of internal consistency and reliability of the questionnaire, a confirmatory factor analysis, and the association between the different CEBQ scales and the children’s BMI. Results: A total of 197 children completed variables; 97 of them were boys (49.2%) and 100 girls (50.8%). Mean age of the total sample was 4.7 ± 0.9 years. There was a high test-re-test reliability of the questionnaire with values close to 1, with an average of 0.66 and a good internal consistency (Cronbach alpha with values above 0.7), so that a high reliability is established between the items in each scale. A gradual positive association was found between the score of different “pro-intake” scales of the CEBQ: “Food Responsiveness, ” “Emotional Overeating, ” and “Enjoyment of food” and the children’s BMI; at the opposite, negative associations were observed between BMI and the score of anti-intake scales “Satiety Responsiveness, ” “Slowness in Eating, ” and “Emotional Undereating.” Conclusion: The Spanish version of the CEBQ is a useful tool to assess the eating behavior of Spanish children because the high reliability and internal validity. There is a significant association between eating behavior and BMI in Spanish children. Copyright © 2022 Jimeno-Martínez, Maneschy, Moreno, Bueno-Lozano, De Miguel-Etayo, Flores-Rojas, Jurado-Castro, de Lamas, Vázquez-Cobela, Martinez-Lacruz, Portoles, Martínez, Navas-Carretero, Schröder, Fitó, Babio, Salas-Salvadó, Leis, Gil-Campos and Rupérez

    Study of the immunologic response of marine-derived collagen and gelatin extracts for tissue engineering applications

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    9 pages, 3 figures, 2 tablesThe host immunologic response to a specific material is a critical aspect when considering it for clinical implementation. Collagen and gelatin extracted from marine sources have been proposed as biomaterials for tissue engineering applications, but there is a lack of information in the literature about their immunogenicity. In this work, we evaluated the immune response to collagen and/or gelatin from blue shark and codfish, previously extracted and characterized. After endotoxin evaluation, bone marrow-derived macrophages were exposed to the materials and a panel of pro- and anti-inflammatory cytokines were evaluated both for protein quantification and gene expression. Then, the impact of those materials in the host was evaluated through peritoneal injection in C57BL/6 mice. The results suggested shark collagen as the less immunogenic material, inducing low expression of pro-inflammatory cytokines as well as inducible nitric oxide synthase (encoded by Nos2) and high expression of Arginase 1 (encoded by Arg1). Although shark gelatin appeared to be the material with higher pro-inflammatory expression, it also presents a high expression of IL-10 (anti-inflammatory cytokine) and Arginase (both markers for M2-like macrophages). When injected in the peritoneal cavity of mice, our materials demonstrated a transient recruitment of neutrophil, being almost non-existent after 24 hours of injection. Based on these findings, the studied collagenous materials can be considered interesting biomaterial candidates for regenerative medicine as they may induce an activation of the M2-like macrophage population, which is involved in suppressing the inflammatory processes promoting tissue remodelingThe authors would like to acknowledge to European Union for the financial support under the scope of European Regional Development Fund (ERDF) through the projects 0302_CVMAR_I_1_P and 0474_BLUEBIOLAB_1_E (program INTERREG España-Portugal 2014/2020). Funding from the Portuguese Foundation for Science and Technology for the grant of A. L. Alves (Ana Luísa Alves) under Doctoral Programme Do*Mar (PD/BD/127995/2016) is also acknowledgedPeer reviewe

    Corrigendum: Reliability and validation of the child eating behavior questionnaire in 3- to 6-year-old Spanish children

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    A corrigendum on Reliability and validation of the child eating behavior questionnaire in 3- to 6-year-old Spanish children by Jimeno-Martínez, A., Maneschy, I., Moreno, L. A., Bueno-Lozano, G., De Miguel-Etayo, P., Flores-Rojas, K., Jurado-Castro, J. M., de Lamas, C., Vázquez-Cobela, R., Martinez-Lacruz, R., Portoles, O., Martínez, J. A., Navas-Carretero, S., Schröder, H., Fitó, M., Babio, N., Salas-Salvadó, J., Leis, R., Gil-Campos, M., and Rupérez, A. I. (2022). Front. Psychol. 13:705912. doi: 10.3389/fpsyg.2022.70591

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro
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