Effect of carbonization conditions of polyaniline on its catalytic activity towards ORR. Some insights about the nature of the active sites

N-doped carbon materials were obtained using polyaniline (PANI) as precursor. Heat treatment of PANI and de-doped PANI (PANId) was performed using different temperatures −600 and 800 °C–. Two different atmospheres were used during the treatment: an inert atmosphere (N2) and another one consisting on a slightly oxidizing mixture of gases (3000 ppm O2 in N2). The prepared materials at 800 °C showed high values of capacitance, up to 170 and 255 F g−1 in basic and acid electrolytes, respectively, in spite of their low surface area. The electrocatalytic activity towards oxygen reduction reaction (ORR) of all materials was studied in basic and acid media. The heat treated materials at 600 °C did not show a good electrocatalytic activity due to their poor electrical conductivity. On the other hand, heat-treated materials at 800 °C showed an enhanced catalytic activity due to their higher conductivity and the presence of nitrogen and oxygen functionalities in the carbon surface. Interestingly, the heat treatment at 800 °C using a slightly oxidant atmosphere produces carbon materials with much higher ORR activity which seems to be related to the larger amount of N-edge and O-edge sites. Preliminary computational studies suggest that the presence of these nitrogen and oxygen functionalities in the vicinities of the carbon atom improves the catalytic performance of N-doped carbon materials in the ORR and that two adjacent active sites can produce the O2 reduction to H2O through a 4 electrons pathway.The authors thank MINECO of Spain and FEDER (CTQ2015-66080-R MINECO/FEDER and MAT2016-76595-R) and Generalitat Valenciana (PROMETEOII/2014/010) for the financial support. CGG gratefully acknowledges Generalitat Valenciana for the financial support through a Santiago Grisolía grant (GRISOLIA/2013/005)

Tailoring the surface chemistry of carbon materials. A key to improve their applications

La modificación de la química superficial en los materiales carbonosos posibilita la adaptación de sus propiedades con objeto de mejorar su rendimiento en diferentes aplicaciones. En los últimos años se han desarrollado un gran número de técnicas de funcionalización covalente y no-covalente que permiten una modificación selectiva de la química superficial de los materiales carbonosos. Estas técnicas pueden ser catalogadas como métodos químicos o métodos electroquímicos, siendo los últimos más selectivos hacia un heteroátomo o grupo funcional determinado. En esta revisión se muestra una introducción a la química superficial en los materiales carbonosos así como una clasificación y una breve explicación de las técnicas comúnmente empleadas para su modificación.The modification of the surface chemistry of carbon materials makes possible to tune their properties, what is in many cases necessary to enhance their performance in different applications. A large number of covalent and non-covalent functionalization techniques have been developed in the last decades for this purpose, providing a toolset to achieve effective tailoring of surface functionalities. Depending on the employed procedure, these techniques can be regarded as chemical or electrochemical, being the electrochemical more selective to a specific heteroatom or functional group. This review contains an introduction to the surface chemistry of carbon materials as well as a classification and a brief explanation of the most commonly used techniques for its modification.Los autores agradecen financiación recibida MINECO y FEDER (CTQ2015-66080-R MINECO/FEDER y JCI-2012-12664). Se agradece también la ayuda de la Generalitat Valenciana (PROMETEO/2013/038, PROMETEOII/2014/010 y GRISOLIA/2013/005)

Estudio de factibilidad para la comercialización de carne de conejo en Soacha Comuna 2

Soacha se ha convertido en un municipio cada vez más comercial y competitivo por su aumento de población, inicialmente el municipio de Soacha es donde se llevara a cabo el proyecto de la comercialización en carne de conejo. Las virtudes de esta carne son poco conocidas entre los consumidores, su bajo contenido de colesterol, grasas saturadas, sodio, y alto contenido de proteína digerible la hacen una alternativa ideal para dietas de personas con problemas de salud. Esta carne no se aprovecha al máximo ya que mucha gente desconoce cómo procesarla. Se pretende evidenciar la importancia de ofrecer alternativas para el consumo de carne diferente a la de res y que no ha mostrado hasta el momento el nivel de distribución y consumo que se espera teniendo en cuenta que no se ha diseñado una estrategia de producción y comercialización, que provoque la competitividad del producto (carne de conejo). Por lo anterior lo que se pretende es explotar los sistemas de comercialización respectivo, manejo de trazabilidad teniendo en cuenta su momento de producción, crianza hasta su debido sacrificio y luego su comercialización

Modeling of oxygen reduction reaction in porous carbon materials in alkaline medium. Effect of microporosity

The role of porosity, and more specifically, microporosity, in the performance of carbon materials as Oxygen Reduction Reaction (ORR) catalysts in alkaline medium still has to be clarified. For this purpose, a highly microporous KOH-activated carbon and a microporous char have been prepared and their ORR performance in alkaline media were compared to that of two commercial carbon blacks with low and high surface areas, respectively. Interestingly, all carbon materials show a two-wave electrocatalytic process, where the limiting current and the number of electron transferred increase when going to more negative potentials. The limiting current and onset potential of the second wave is positively related to the amount of microporosity, and H2O2 electrochemical reduction tests have confirmed that the second wave could be related to the catalytic activity towards this reaction. In accordance to these findings, a model is developed that takes into account narrow and wide micropores in both charge transfer reactions and the mass transfer rate of O2 and H2O2. This model successfully reproduces the experimental electrochemical response during ORR of the analyzed porous carbon materials and suggests the important role of narrow micropores in H2O2 reduction.This work was supported by MINECO (CTQ2015-66080-R MINECO/FEDER) and Heiwa Nakajima Foundation

Successful functionalization of superporous zeolite templated carbon using aminobenzene acids and electrochemical methods

A novel and selective electrochemical functionalization of a highly reactive superporous zeolite templated carbon (ZTC) with two different aminobenzene acids (2-aminobenzoic and 4-aminobenzoic acid) was achieved. The functionalization was done through potentiodynamic treatment in acid media under oxidative conditions, which were optimized to preserve the unique ZTC structure. Interestingly, it was possible to avoid the electrochemical oxidation of the highly reactive ZTC structure by controlling the potential limit of the potentiodynamic experiment in presence of aminobenzene acids. The electrochemical characterization demonstrated the formation of polymer chains along with covalently bonded functionalities to the ZTC surface. The functionalized ZTCs showed several redox processes, producing a capacitance increase in both basic and acid media. The rate performance showed that the capacitance increase is retained at scan rates as high as 100 mV s−1, indicating that there is a fast charge transfer between the polymer chains formed inside the ZTC porosity or the new surface functionalities and the ZTC itself. The success of the proposed approach was also confirmed by using other characterization techniques, which confirmed the presence of different nitrogen groups in the ZTC surface. This promising method could be used to achieve highly selective functionalization of highly porous carbon materials.The authors would like to thank MINECO and FEDER (CTQ2012/31762, MAT2013-42007-P and PRI-PIBJP-2011-0766), Generalitat Valenciana (PROMETEO/2013/038 and PROMETEOII/2014/010) for the financial support. RRR thanks MINECO for a ‘Juan de la Cierva’ contract (JCI-2012-12664). CGG gratefully acknowledges Generalitat Valenciana for the financial support through a Santiago Grisolía Grant (GRISOLIA/2013/005). This work is also supported by the Nano-Macro Materials, Devices and System Research Alliance and by Network Joint Research Center for Materials and Devices

Factors associated with the development of septic shock in patients with candidemia: a post hoc analysis from two prospective cohorts

[Background] Almost one third of the patients with candidemia develop septic shock. The understanding why some patients do and others do not develop septic shock is very limited. The objective of this study was to identify variables associated with septic shock development in a large population of patients with candidemia.[Methods] A post hoc analysis was performed on two prospective, multicenter cohort of patients with candidemia from 12 hospitals in Spain and Italy. All episodes occurring from September 2016 to February 2018 were analyzed to assess variables associated with septic shock development defined according to The Third International Consensus Definition for Sepsis and Septic Shock (Sepsis-3).[Results] Of 317 candidemic patients, 99 (31.2%) presented septic shock attributable to candidemia. Multivariate logistic regression analysis identifies the following factors associated with septic shock development: age > 50 years (OR 2.57, 95% CI 1.03–6.41, p = 0.04), abdominal source of the infection (OR 2.18, 95% CI 1.04–4.55, p = 0.04), and admission to a general ward at the time of candidemia onset (OR 0.21, 95% CI, 0.12–0.44, p = 0.001). Septic shock development was independently associated with a greater risk of 30-day mortality (OR 2.14, 95% CI 1.08–4.24, p = 0.02).[Conclusions] Age and abdominal source of the infection are the most important factors significantly associated with the development of septic shock in patients with candidemia. Our findings suggest that host factors and source of the infection may be more important for development of septic shock than intrinsic virulence factors of organisms.This study was funded by a research grant from the Ministerio de Sanidad y Consumo, Instituto de Salud Carlos III [FIS PI15/00744], European Regional Development Fund (ERDF); CGV is a recipient of an INTENSIFICACIÓ Grant from the “Strategic plan for research and innovation in health-PERIS 2016-2020” and forms part of the Fungi CLINIC Research group (AGAUR-Project 2017SGR1432 of the Catalan Health Agency)

Factors associated with the development of septic shock in patients with candidemia: a post hoc analysis from two prospective cohorts

Background: Almost one third of the patients with candidemia develop septic shock. The understanding why some patients do and others do not develop septic shock is very limited. The objective of this study was to identify variables associated with septic shock development in a large population of patients with candidemia. Methods: A post hoc analysis was performed on two prospective, multicenter cohort of patients with candidemia from 12 hospitals in Spain and Italy. All episodes occurring from September 2016 to February 2018 were analyzed to assess variables associated with septic shock development defined according to The Third International Consensus Definition for Sepsis and Septic Shock (Sepsis-3). Results: Of 317 candidemic patients, 99 (31.2%) presented septic shock attributable to candidemia. Multivariate logistic regression analysis identifies the following factors associated with septic shock development: age > 50 years (OR 2.57, 95% CI 1.03–6.41, p = 0.04), abdominal source of the infection (OR 2.18, 95% CI 1.04–4.55, p = 0.04), and admission to a general ward at the time of candidemia onset (OR 0.21, 95% CI, 0.12–0.44, p = 0.001). Septic shock development was independently associated with a greater risk of 30-day mortality (OR 2.14, 95% CI 1.08–4.24, p = 0.02). Conclusions: Age and abdominal source of the infection are the most important factors significantly associated with the development of septic shock in patients with candidemia. Our findings suggest that host factors and source of the infection may be more important for development of septic shock than intrinsic virulence factors of organisms

Patrimonio cultural : Contextos en transición: pedagogía, cultura y economía sustentable en comunidades americanas

El presente documento es una recopilación de experiencias que fueron parte del I Encuentro Internacional de Patrimonio Cultural celebrado en la Corporación Universitaria Minuto de Dios – UNIMINUTO en septiembre del 2019; así como de otros aportes de investigadores colombianos a la comprensión de temas relacionados con la tradición, la cultura, la memoria y el ecosistema natural en el cual como humanos nos desenvolvemos. Los aportes tienen origen en reflexiones de diferentes países desde Argentina hasta Canadá y cumple con el propósito de realizar un diálogo multidisciplinar de los aspectos que componen el patrimonio cultural en el continente americano

Patrimonio cultural : Contextos en transición: pedagogía, cultura y economía sustentable en comunidades americanas

El presente documento es una recopilación de experiencias que fueron parte del I Encuentro Internacional de Patrimonio Cultural celebrado en la Corporación Universitaria Minuto de Dios – UNIMINUTO en septiembre del 2019; así como de otros aportes de investigadores colombianos a la comprensión de temas relacionados con la tradición, la cultura, la memoria y el ecosistema natural en el cual como humanos nos desenvolvemos. Los aportes tienen origen en reflexiones de diferentes países desde Argentina hasta Canadá y cumple con el propósito de realizar un diálogo multidisciplinar de los aspectos que componen el patrimonio cultural en el continente americano

Medio ambiente, sociedad, ética, auditoría y educación: reflexiones desde la disciplina contable.

Los servicios y desarrollos tecnológicos en todos los sectores económicos, al igual que la actualidad social, educativa, ambiental y agropecuaria en el mundo, constituyen oportunidades para que los contadores públicos se alejen de los procesos netamente manuales, y se acerquen al desarrollo de actividades que agreguen mayor valor a las unidades económicas en las cuales se desempeñan profesionalmente; en consecuencia, la academia recibe en la misma dimensión retos importantes que conllevan revisar y actualizar constantemente los contenidos, medios y escenarios educativos, a través de los cuales se cumple con la misión de formar contadores públicos idóneos para la sociedad. El programa de Contaduría Pública de la Corporación Universitaria Minuto de Dios – UNIMINUTO, UVD, consiente de la responsabilidad que tiene al ser uno de los programas con mayor número de estudiantes actualmente en Colombia, ha cimentado a lo largo de sus primeros ocho años bases adecuadas y orientadas a constituir una comunidad académica reconocida por sus aportes alternativos a la profesión y a la industria contable en general. El libro Medio ambiente, sociedad, ética, auditoría y educación en su segunda versión es una muestra de cómo el III Encuentro Nacional y II Internacional de Investigación Contable UNIMINUTO UVD, llevado a cabo en Bogotá en Octubre del 2018, se convirtió en un espacio extraordinario en el que se reunieron representantes de los veintiún lugares de oferta del programa de Contaduría Pública UNIMINUTO UVD, para compartir los avances de los proyectos que se tejen diariamente en diferentes lugares del territorio nacional, y que hacen parte integral de las cuatro sublíneas de investigación que se desarrollan al interior del programa y que se visualizan claramente lo largo del presente libro