21 research outputs found

    Dibenzothiophene adsorption at boron doped carbon nanoribbons studied within density functional theory

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    "The adsorption of dibenzothiophene (DBT) on bare and boron-doped armchair carbon nanoribbons (ACNRs) is being investigated in the framework of the density functional theory by implementing periodic boundary conditions that include corrections from dispersion interactions. The reactivity of the ACNRs is characterized by using the Fukui functions as well as the electrostatic potential as local descriptors. Non-covalent adsorption mechanism is found when using the local Perdew-Becke-Ernzerhof functional, regardless of the DBT orientation and adsorption location. The dispersion interactions addition is a milestone to describe the adsorption process. The charge defects introduced in small number (i.e., by doping with B atoms), within the ACNRs increases the selectivity towards sulfur mainly due to the charge depletion at B sites. The DBT magnitude in the adsorption energy shows non-covalent interactions. As a consequence, the configurations where the DBT is adsorbed on a BC3 island increase the adsorption energy compared to random B arrangements. The stability of these configurations can be explained satisfactorily in terms of dipole interactions. Nevertheless, from the charge-density difference analysis and the weak Bader charge-distribution interactions cannot be ruled out completely. This is why the electronic properties of the ribbons are analyzed in order to elucidate the key role played by the B and DBT states in the adsorbed configurations.

    Efecto de Arthrobacter agilis UMCV2 sobre la germinación y crecimiento de Pinus devoniana Lindley

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    Soil microorganisms are essential for growth, emergence and development in all plants. In our study we decided to evaluate the effect that A. agilis UMCV2 rhizobacteria had on germination and growth of plants of economic-forest interest as P. devoniana to an age of 65 days. Our results show that the UMCV2 bacteria promoted growth of P. devoniana at this early stage of development, further highlighting that despite the short time of interaction between these two, the bacterium was able to increase the rate of germination, increase the size of shoot and generate a proliferation of lateral roots. The data shows a huge potential for using inoculum both in the greenhouse and in open ground and generate a growth promoting species of interest in both agricultural and forest, thereby reducing production periods depending on the crop.Los microorganismos del suelo son indispensables para el crecimiento, emergencia y desarrollo de prácticamente todas las plantas. En nuestro trabajo decidimos evaluar el efecto que ejerce la rizobacteria A. agilis UMCV2 sobre la germinación y el crecimiento de plantas de interés económico-forestal como P. devoniana hasta una edad de 65 días. Nuestros resultados muestran que la bacteria UMCV2 promovió el crecimiento de P. devoniana en esta primera etapa de desarrollo, resaltando además que a pesar del corto tiempo de interacción entre estos dos, la bacteria fue capaz de incrementar el índice de germinación, aumentar la talla de la parte aérea y de generar una proliferación de raíces laterales. Los datos señalan un enorme potencial para usar inóculos tanto en condiciones de invernadero como en suelo abierto y generar una promoción del crecimiento en especies de interés tanto agrícola como forestal, de esa manera reducir los periodos de producción en función del cultivo

    Comparison of five pretreatments for the production of fermentable sugars obtained from Pinus pseudostrobus L. wood

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    To benefit from the use of a waste product such as pine sawdust from a sawmill in Michoacán, Mexico, five different pretreatments for the production of reducing sugars by enzymatic hydrolysis were evaluated (sodium hydroxide, sulfuric acid, steam explosion, organosolv and combined method nitric acid / sodium hydroxide). The main finding of the study was that the pretreatment with 6 % HNO3 and 1 % NaOH led to better yields than those obtained with sodium hydroxide, dilute sulfuric acid, steam explosion, and organosolv pretreatments. Also, HNO3 yields were maximized by the factorial method. With those results the maxima concentration of reducing sugar found was 97.83 ± 1.59, obtained after pretreatment with 7.5 % HNO3 at 120 °C for 30 minutes; followed by 1 % of NaOH at 90 °C for 30 minutes at pH 4.5 for 168 hours with a load enzyme of 25 FPU/g of total carbohydrates. Comparing the results obtained by the authors with those reported in the literature, the combined method was found to be suitable for use in the exploitation of sawdust

    Chemical composition of biomass generated in the guava tree pruning

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    Psidium guajava L. (Myrtaceae) is a native plant of Central America and is now widely cultivated in many tropical regions of the world for the fruit production. In Mexico, in the guava orchards common practices to control fruit production are: water stress, defoliation and pruning. In this study, we report the chemical composition of the biomass (branches and leaves) generated in the pruning practices. The results ranged as follows: pH (4.98-5.88), soda solubility (39.01-70.49 %), ash (1.87-8.20 %); potassium and calcium were the major inorganic elements in ash. No heavy metals were detected in the studied samples; total solubility (15.21-46.60 %), Runkel lignin (17.77-35.26 %), holocellulose (26.56 -69.49 %), α-cellulose (15.53-35.36 %), hemicelluloses (11.02-34.12 %), tannins in aqueous extracts (3.81-9.06 %), and tannins in ethanolic extracts (3.42-15.24 %)

    Añadiendo mecanismos de ayuda en un juez on-line automático para soporte a mentorías académicas

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    Todos los jueces en línea, incluído en sus inicios ¡Acepta el reto! (https://www.aceptaelreto.com) desarrollado por profesores de la UCM, adolecen de un problema de realimentación al usuario: cuando el visitante hace un envío incorrecto el sistema no es capaz de dar información específica del error. El documento es la memoria final de un Proyecto de Innovación y Mejora de la Calidad Docente (PIMCD) de 2017/2018 en el que se puso en marcha un sistema de pistas en el juez

    Impact of operatoŕs experience on peri-procedural outcomes with Watchman FLX: Insights from the FLX-SPA registry

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    Background: The Watchman FLX is a device upgrade of the Watchman 2.5 that incorporates several design enhancements intended to simplify left atrial appendage occlusion (LAAO) and improve procedural outcomes. This study compares peri-procedural results of LAAO with Watchman FLX (Boston Scientific, Marlborough, Massachusetts) in centers with varying degrees of experience with the Watchman 2.5 and Watchman FLX. Methods: Prospective, multicenter, 'real-world' registry including consecutive patients undergoing LAAO with the Watchman FLX at 26 Spanish sites (FLX-SPA registry). Implanting centers were classified according to the center's prior experience with the Watchman 2.5. A further division of centers according to whether or not they had performed ≤ 10 or > 10Watchman FLX implants was prespecified at the beginning of the study. Procedural outcomes of institutions stratified according to their experience with the Watchman 2.5 and FLX devices were compared. Results: 359 patients [mean age 75.5 (SD8.1), CHA2DS2-VASc 4.4 (SD1.4), HAS-BLED 3.8(SD0.9)] were included. Global success rate was 98.6%, successful LAAO with the first selected device size was achieved in 95.5% patients and the device was implanted at first attempt in 78.6% cases. There were only 9(2.5%) major peri-procedural complications. No differences in efficacy or safety results according to the centeŕs previous experience with Watchman 2.5 and procedural volume with Watchman FLX existed. Conclusions: The Watchman FLX attains high procedural success rates with complete LAA sealing in unselected, real-world patients, along with a low incidence of peri-procedural complications, regardless of operatoŕs experience with its previous device iteration or the number of Watchman FLX devices implanted

    La ciudad como experiencia de conocimiento: nuevas metodologías de aprendizaje, iniciación a la investigación y extensión universitaria a partir de la historia urbana

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    El proyecto de innovación docente "La ciudad como experiencia de conocimiento: nuevas metodologías de aprendizaje, iniciación a la investigación y extensión universitaria a partir de la historia urbana" es una iniciativa de varios profesores, investigadores y estudiantes de los grados de Historia e Historia del Arte, que pretende aprovechar todas las posibilidades que proporciona el estudio de la ciudad en el proceso de enseñanza y aprendizaje, la iniciación a la investigación, el fomento de la interdisciplinariedad y el desarrollo de actividades de extensión universitaria

    EDUCACIÓN AMBIENTAL Y SOCIEDAD. SABERES LOCALES PARA EL DESARROLLO Y LA SUSTENTABILIDAD

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    Este texto contribuye al análisis científico de varias áreas del conocimiento como la filosofía social, la patología, la educación para el cuidado del medio ambiente y la sustentabilidad que inciden en diversas unidades de aprendizaje de la Licenciatura en Educación para la Salud y de la Maestría en Sociología de la SaludLas comunidades indígenas de la sierra norte de Oaxaca México, habitan un territorio extenso de biodiversidad. Sin que sea una área protegida y sustentable, la propia naturaleza de la región ofrece a sus visitantes la riqueza de la vegetación caracterizada por sus especies endémicas que componen un paisaje de suma belleza

    Efecto de Arthrobacter agilis UMCV2 sobre la germinación y crecimiento de Pinus devoniana Lindley

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    Abstract: Soil microorganisms are essential for growth, emergence and development in all plants. In our study we decided to evaluate the effect that A. agilis UMCV2 rhizobacteria had on germination and growth of plants of economic-forest interest as P. devoniana to an age of 65 days. Our results show that the UMCV2 bacteria promoted growth of P. devoniana at this early stage of development, further highlighting that despite the short time of interaction between these two, the bacterium was able to increase the rate of germination, increase the size of shoot and generate a proliferation of lateral roots. The data shows a huge potential for using inoculum both in the greenhouse and in open ground and generate a growth promoting species of interest in both agricultural and forest, thereby reducing production periods depending on the crop.Resumen: Los microorganismos del suelo son indispensables para el crecimiento, emergencia y desarrollo de prácticamente todas las plantas. En nuestro trabajo decidimos evaluar el efecto que ejerce la rizobacteria A. agilis UMCV2 sobre la germinación y el crecimiento de plantas de interés económico-forestal como P. devoniana hasta una edad de 65 días. Nuestros resultados muestran que la bacteria UMCV2 promovió el crecimiento de P. devoniana en esta primera etapa de desarrollo, resaltando además que a pesar del corto tiempo de interacción entre estos dos, la bacteria fue capaz de incrementar el índice de germinación, aumentar la talla de la parte aérea y de generar una proliferación de raíces laterales. Los datos señalan un enorme potencial para usar inóculos tanto en condiciones de invernadero como en suelo abierto y generar una promoción del crecimiento en especies de interés tanto agrícola como forestal, de esa manera reducir los periodos de producción en función del cultivo
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