21 research outputs found

    Proving ligand structure-reactivity correlation on multinuclear copper electrocatalysts supported on carbon black for the oxygen reduction reaction

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    Bioinspired transition-metal catalysts seek to mimic the specific active site of metalloenzymes, as the multicopper oxidase, that can efficiently reduce dioxygen to water via a complete 4-electrons mechanism at low overpotential. However, the multicopper oxidase enzymes lack stability under operando conditions, hampering their application in fuel cell electrodes. Bioinspired multicopper catalysts present a remarkable electrocatalytic activity for the oxygen reduction reaction (ORR), where the structure and electronic properties of the ligands play a fundamental role. In this work, we explore the instantaneous catalytic activity and its evolution under operando conditions of two multicopper catalysts with different ligand flexibility, pyridyl ligand (CuL1), and pyridylmethyl ligand (CuL2), by conventional electrochemical techniques and scanning electrochemical microscopy (SECM). Both catalysts present similar instantaneous electrocatalytic activity with no significant role of the ligand, but there is a change in the mechanism. While the rigidity of CuL1 reduces the dioxygen via direct 4e-, the catalyst with higher flexibility (CuL2) follows a 2e−x 2e− mechanism. The production of H2O2 as ORR byproduct evaluated by rotating ring-disk electrode (RRDE) and stability test evaluated under ORR operating conditions by SECM imaging of both catalysts demonstrated a higher decrease in catalytic activity and higher H2O2 production in CuL2 than in CuL1, which evidences a ligand structure-reactivity correlation. These results contribute to the rational design of next generation of copper catalysts and open the door to a new methodology to evaluate the activity evolution under operando conditions by SECMThis work has been supported by ECOS Sud-Chile CONICYT program (Project C17E10/170037), FONDECYT Project 1161117, FONDECYT Project 11221073, FONDECYT Postdoctoral Project 3170330, and ACT192175

    Prospectiva territorial SENA regional Valle al 2030

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    Prospectiva territorial SENA regional Valle al 2030 compatible con las propuestas de desarrollo regional en la cual mediante el acopio, revisión y análisis de información de las tendencias internacionales, nacionales, locales y de la organización se identificaron las principales direccionadores, productos, tecnologías y recursos evaluando el nivel de importancia y gobernabilidad de los factores organizacionales más críticos así como conclusiones y recomendaciones.SENA regional Valle territorial prospect by 2030 compatible with regional development proposals in which, through the collection, review and analysis of information on international, national, local and organizational trends, the main drivers, products, technologies and resources were identified, evaluating the level of importance and governance of the most critical organizational factors as well as conclusions and recommendations.Identificación de dimensiones, direccionadores y factores -- Mapa de trayectoria del sena regional Valle -- Matriz de importancia y gobernabilidad -- Mundo e incertidumbre -- Direccionador desarrollo económico, empleo y demografía -- Tendencias de América Latina -- Tendencias nacionales -- Tendencias regionales -- Tendencias locales -- Situación étnico-cultural -- Institucionalidad y gobernabilidad -- Escenario desarrollo económico, empleo y demografía -- Direccionador seguridad y soberanía alimentaria -- Principales tendencias de América Latina -- Principales tendencias locales, regionales y nacionales -- Escenario seguridad alimentaria en el SENA regional Valle -- Direccionador industria 4.0 -- Definición -- Tendencias mundiales -- Principales tendencias de América Latina -- Principales tendencias locales regionales y nacionales -- SENA regional Valle y la industria 4.0 -- Direccionador ambiente -- Tendencias de América Latina -- Principales tendencias locales, regionales y nacionales -- Línea de base direccionador ambiente en El SENA Regional Valle -- Covid-19 y el impacto ambiental en el Valle del cauca -- Escenarios direccionador ambiente -- Direccionador infraestructura sostenible -- Principales tendencias de América Latina -- Principales tendencias locales, regionales y nacionales -- Diagnóstico infraestructura sostenible -- Escenario infraestructura sostenible -- Debilidades, oportunidades, fortalezas y amenazas (DOFA) -- Conclusiones -- Escenario Apuesta -- Escenarios posibles -- Conclusiones -- RecomendacionesPrimera ediciónna197 página

    Caracterización de la investigación, el desarrollo tecnológico y la innovación en el sector productivo de la región fronteriza colombo venezolana

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    En el libro se presenta la recopilación de proyectos de Investigación e Innovación tecnológica como resultado del desarrollo de actividades investigativas, donde se involucran grupos de investigación y semilleros, instructores investigadores, docentes universitarios, administrativos, aprendices, estudiantes universitarios y empresarios del ámbito regional, nacional e internacional, quienes motivados por su espíritu emprendedor e innovador le apostaron a involucrarse en proyectos desde las áreas de automatización, electrónica y telecomunicaciones, gestión de hábitat , Diseño e implementación de soluciones en TIC, Gestión del negocio emprendimiento y empresarismo, innovación educativa y diseño de vestuario.The book presents the compilation of Research and Technological Innovation projects as a result of the development of research activities, where research groups and seedbeds, research instructors, university teachers, administrative staff, apprentices, university students and entrepreneurs from the regional, national level are involved. and international, who, motivated by his entrepreneurial and innovative spirit, bet him to get involved in projects from the areas of automation, electronics and telecommunications, habitat management, Design and implementation of ICT solutions, Business management, entrepreneurship and entrepreneurship, educational innovation and design. wardrobe.Caracterización de la investigación, el desarrollo tecnológico y la innovación en el sector productivo de la región fronteriza colombo venezolana -- Modelo de un sistema hidráulico controlado por redes neuronales – Sistema de gestión y monitoreo de consumo de servicios domiciliarios fomentando la “sostenibilidad inductiva” -- Cálculo de los parámetros hidráulicos y mecánicos de un prototipo robótico para la fumigación de cultivos de media y baja altura -- Manipulador robótico en el sistema integrado por computadora plataforma Cim-C -- Planificación multinivel y conflictos generados por la transformación de los espacios agrarios en el sector periurbano fronterizo de los trapiches, villa del rosario. -- Herramienta tecnológica para la vinculación del aprendiz sena del programa de articulación media con el sector productivo de la ciudad de bucaramanga -- Global kids máquina de intercambio financiero Global Kids financial Exchange machine – Desarrollo de aplicación móvil para la enseñanza e instrucción del área de documentación y gestión administrativa -- Diseño de una aplicación informática on-line para optimizar la gestión de los procesos, tramites e informes de los materiales de formación del sena centro cies regional norte de santander -- creación sala hub de consultoría estratégica mipymes norte de santander -- Diseño recorrido virtual de gestión documental Regional Norte de Santander: SENA -- Factores de riesgo provocadas por el incremento de estrés en las empresas industriales mexicanas -- Logística de la comercialización del plátano procedente de los municipios buenavista, córdoba y pijao -- Sistema de información móvil integrador de procesos formativos del sena con la comunidad educativa -- Sistematización de la información contable y financiera de los proyectos de aula en la media técnica -- BANKIDS juego didáctico y financiero -- Causas que originan la mala ortografía en los aprendices de la red de gestión administrativa y servicios financieros -- Informe sobre la deserción de aprendices de gestión administrativa y servicios financieros -- uso de las ntic desde el semillero de investigación e innovación virtual e-innovacmm centro metalmecánicona207 página

    Caminando en la ruta sentipensante: configuración de experiencias pedagógicas nivel inicial

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    494 páginasEste texto es realizado en el contexto del Plan de Desarrollo 2016 – 2020, “Bogotá mejor para todos”, en el que se señala: Bogotá es entendida como una ciudad educadora, en la que todos los ciudadanos son agentes educadores y todos los espacios pueden ser escenarios pedagógicos para el aprendizaje. Una ciudad educadora tiene como centro el conocimiento e inspira aprendizaje, formas y lenguajes para reconocernos, para reencontrarnos; los espacios para el aprendizaje son entendidos como espacios para la vida, en los que se posibilita la investigación y la innovación para vivir mejor, para reinventarnos como ciudad, una ciudad mejor para todos. Los dieciocho textos aquí presentados, fruto del acompañamiento pedagógico realizado por el IDEP en 2019, son base y referente para seguir aportando en la configuración y consolidación de comunidades de saber y práctica pedagógica de la ciudad, así como en la conformación de colectivos y redes de maestros. Son la evidencia de un potente trabajo de acompañamiento a experiencias de nivel inicial, caracterizadas por contar con ideas o avances para problematizar, estructurar, fundamentar, elaborar estrategias y un plan de acción

    Nuevos escenarios para la docencia universitaria : entornos híbridos y pedagogías emergentes.

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    Memorias del IX Simposio Internacional de Docencia Universitaria (SIDU)Los trabajos reunidos en esta Memoria representan una contribución importante al campo de la educación y de la docencia universitaria, en tanto muestran distintas maneras de responder a las problemáticas educativas cotidianas y presentan propuestas para afrontar los retos emergentes en el campo de la educación superior. Invitamos a los lectores a realizar una lectura atenta y crítica de los trabajos compilados en esta publicación. Estamos seguros de que este acercamiento propiciará la reflexión y el análisis riguroso de los objetos de estudio abordados por los autores, y estimulará la generación de nuevos proyectos de investigación, intervención e innovación educativa que incidan en el desarrollo de mejores prácticas de docencia en educación media superior y superior.Pimera edición digitaldoi.org/10.56019/EDU-CETYS.2024.182

    MIBiG 3.0 : a community-driven effort to annotate experimentally validated biosynthetic gene clusters

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    With an ever-increasing amount of (meta)genomic data being deposited in sequence databases, (meta)genome mining for natural product biosynthetic pathways occupies a critical role in the discovery of novel pharmaceutical drugs, crop protection agents and biomaterials. The genes that encode these pathways are often organised into biosynthetic gene clusters (BGCs). In 2015, we defined the Minimum Information about a Biosynthetic Gene cluster (MIBiG): a standardised data format that describes the minimally required information to uniquely characterise a BGC. We simultaneously constructed an accompanying online database of BGCs, which has since been widely used by the community as a reference dataset for BGCs and was expanded to 2021 entries in 2019 (MIBiG 2.0). Here, we describe MIBiG 3.0, a database update comprising large-scale validation and re-annotation of existing entries and 661 new entries. Particular attention was paid to the annotation of compound structures and biological activities, as well as protein domain selectivities. Together, these new features keep the database up-to-date, and will provide new opportunities for the scientific community to use its freely available data, e.g. for the training of new machine learning models to predict sequence-structure-function relationships for diverse natural products. MIBiG 3.0 is accessible online at https://mibig.secondarymetabolites.org/

    Strategies to improve the catalytic activity and stability of bioinspired Cu molecular catalysts for the ORR

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    The oxygen reduction reaction (ORR) is essential for energy conversion devices such as fuel cells and metal-air batteries. The use of expensive and scarce noble metal materials to catalyze the ORR is a limitation for the massification of these energy conversion technologies. Copper molecular catalysts that mimic the active sites of metalloenzymes such as laccase are under continuous development. In this minireview, we present the strategies to increase the activity and stability of the copper catalysts for the ORR. The flexibility, lability, and electronic character of the ligands are crucial to promote the ORR. In addition, the use of polymers as backbone for multicopper catalysts and the synthesis of copper carbon-based pyrolyzed catalysts present remarkable results with promissory applicationsThis work has been supported by FONDECYT 11221073, FONDECYT 1221798, FONDECYT Postdoctoral Project 3170330 and Anillo Project ACT-19217

    Fe3O4 Templated Pyrolyzed Fe N C Catalysts. Understanding the role of N-Functions and Fe3C on the ORR Activity and Mechanis

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    Pyrolyzed non-precious metal catalysts have been proposed as an alternative to substitute the expensive and scarce noble metal catalysts in several conversion energy reactions. For the oxygen reduction reaction (ORR), the pyrolyzed catalyst M−N−C (M: Fe or Co) presents remarkable catalytic activity in acid and alkaline media. These pyrolyzed materials show a high heterogeneity of active sites being the most active in the MNx moieties. The activity and stability of these catalysts are also conditioned by other structural parameters such as the area, the N-doping, and by the presence of metal particles. In this study, we explore the use of Fe3O4 nanoparticles as templates and as iron sources to synthesize Fe−N−C. The best performance for the ORR in acidic media was reached with the catalysts using nanoparticles covered by PANI and iron salts as the precursor, with an onset potential of 0.85 vs. RHE and a direct 4-electrons mechanism. We corroborated the use of the catalysts’ redox potential as reactivity descriptors and discussed the detrimental role of the presence of Fe3C metallic particles in the mechanism. Based on the experimental results, we performed DFT calculations to explore the influence of N-doped species on the electronic density of the iron centers of FeN4 active sites, and we propose a theoretical model for increasing the activity based on the distance and ratio of N-doping to iron centerknowledgements This work was supported by Fondecyt Regular Project 1161117, Conicyt Scholarship 21160212, Fondecyt Postdoctoral Projects 3180509 and 3170330, and Anillo Project ACT-192175. By MICIN grant PGC2018-095642-B-I00, MCIN/AEI/10.13039/501100011033 RTI2018-095303-B-C51, by ERDF A way to making Europe, and by CISC grant 2021AEP056. The authors acknowledge Jonathan Urra for its technical support in the electr

    Developing risk factors for post traumatic empyema in patients with chest trauma

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    Objective: To establish the risk factors associated to development of empyema posttraumatic in patients with chest trauma managed with closed thoracostomy. Methods: It was a descriptive and observational study of patients with chest trauma who were admitted between January 2013 and May 2014. The variables were evaluated and the results according to management with closed thoracostomy in patients with thoracic trauma was determined. Univariate analysis was performed and measures of central tendency were calculated. Results: In total 240 patients were analyzed. Among them, 10.4% (25) developed posttraumatic empyema. In patients who developed empyema, the mean age was 34.2 years, and the mean injury severity score was 20.6. It was identified as a risk factor closed chest trauma in 68% (17) and 84% coagulated hemothorax trauma. Empyema management thoracoscopy was in 100% of cases. Conclusions: The posttraumatic empyema is a complication that occurs in patients with thoracic trauma. One of the most important risk factors is coagulated hemothorax which could be identified and treated in time to avoid comorbidities during hospital stay

    Structural and Electronic Properties of Polyoxovanadoborates Containing the [V12B18O60] Core in Different Mixed Valence States

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    This review summarizes all published data until April 2015 related to crystalline lattices formed by the [V12B18O60] core, which generates polyanionic clusters with different degrees of protonation and mixed-valence ratios. The negative charge of this cluster is counterbalanced by different cations such as protonated amines, hydronium, and alkaline, and transition metal ions. The cluster is shown to form extended 1D, 2D, or 3D frameworks by forming covalent bonds or presenting hydrogen bond interactions with the present secondary cations. These cations have little influence on the solid state reflectance UV-visible spectra of the polyanionic cluster, but are shown to modify the FT-IR spectra and the magnetic behavior of the different reported species
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