25 research outputs found

    Análisis fitoquímico preliminar y evaluación de la actividad antibacteriana de los extractos de disterigma alaternoides

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    En el presente trabajo se llevó a cabo el estudio fitoquímico preliminar de la especie colombiana Disterigma alaternoides (Kunth) Nied. para identificar los metabolitos secundarios presentes, también se evaluó su actividad biológica, a la que se le pudo comprobar acción antibacteriana frente a dos cepas de bacterias Gram positiva Staphylococcus aureus y Staphylococcus epidermidis. El material vegetal fue recolectado en el páramo de Guasca situado al nordeste de la ciudad de Bogotá (Colombia), en la cordillera oriental de los Andes y se identificó en el Herbario Nacional de Colombia bajo el proyecto “estudio Fitoquímico de la familia Ericaceae” con número 04. Se tomaron 540 g del material vegetal seco (partes aéreas) que fueron extraídos mediante sistema continuo tipo soxlhet con éter de petróleo y etanol. El extracto Etanólico se fraccionó por separado, por el método de separación líquido-líquido continuo con Diclorometano y Acetato de Etilo; las fracciones fueron monitoreadas mediante cromatografía en capa delgada, la Fracción Diclorometano se subfraccionó mediante cromatografía preparativa y la Fracción Acetato de etilo a su vez mediante cromatografía en columna con éter de petróleo, cloroformo y metanol puros y en mezclas de polaridad creciente; las subfracciones se monitorearon mediante cromatografía en capa delgada. De los extractos y fracciones se realizaron pruebas preliminares de identificación de metabolitos secundarios, encontrando resultados positivos para la presencia de flavonoides taninos, saponinas, fenoles y esteroles o triterpenos, Los metabolitos más abundantes en la fracción Diclorometano resultaron ser los fenoles y en la fracción de Acetato de etilo fueron los flavonoides. Al evaluar la actividad antibacteriana de los extractos y fracciones no se observó ninguna actividad frente a las 2 cepas de bacterias Gram negativas, (E. coli y K. pneumoneae) en contraste con los halos de inhibición presentados en las bacterias Gram positiva (S. aureus y S. epidermidis) principalmente el extracto Etanólico y la fracción de Acetato de etilo.Microbiólogo (a) IndustrialPregrad

    Characterization of Actinobacterial Strains as Potential Biocontrol Agents against Macrophomina phaseolina and Rhizoctonia solani, the Main Soil-Borne Pathogens of Phaseolus vulgaris in Cuba

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    Macrophomina phaseolina and Rhizoctonia solani are considered two major soil-borne pathogens of Phaseolus vulgaris in Cuba. Their management is difficult, not only due to their intrinsic biology as soil-borne pathogens, but also because the lack of active ingredients available against these pathogens. Actinobacteria, a heterogeneous bacterial group traditionally known as actinomycetes have been reported as promising biological control agents (BCAs) in crop protection. Thus, the main objective of this study was to evaluate the effectiveness of 60 actinobacterial strains as BCAs against M. phaseolina and R. solani in vitro by dual culture assays. The most effective strains were characterized according to their cellulolytic, chitinolytic and proteolytic extracellular enzymatic activity, as well as by their morphological and biochemical characters in vitro. Forty and 25 out of the 60 actinobacteria strains inhibited the mycelial growth of M. phaseolina and R. solani, respectively, and 18 of them showed a common effect against both pathogens. Significant differences were observed on their enzymatic and biochemical activity. The morphological and biochemical characters allow us to identify all our strains as species belonging to the genus Streptomyces. Streptomyces strains CBQ-EA-2 and CBQ-B-8 showed the highest effectiveness in vitro. Finally, the effect of seed treatments by both strains was also evaluated against M. phaseolina and R. solani infections in P. vulgaris cv. Quivicán seedlings. Treatments combining the two Streptomyces strains (CBQ-EA-2 + CBQ-B-8) were able to reduce significantly the disease severity for both pathogen infections in comparison with the non-treated and inoculated control. Moreover, they showed similar effect than that observed for Trichoderma harzianum A-34 and with Celest® Top 312 FS (Syngenta®; Basilea, Switzerland) treatments, which were included for comparative purposes

    Thresholding Algorithm Optimization for Change Detection to Satellite Imagery

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    To detect changes in satellite imagery, a supervised change detection technique was applied to Landsat images from an area in the south of México. At first, the linear regression (LR) method using the first principal component (1-PC) data, the Chi-square transformation (CST) method using first three principal component (PC-3), and tasseled cap (TC) images were applied to obtain the continuous images of change. Then, the threshold was defined by statistical parameters, and histogram secant techniques to categorize as change or unchanged the pixels. A threshold optimization iterative algorithm is proposed, based on the ground truth data and assessing the accuracy of a range of threshold values through the corresponding Kappa coefficient of concordance. Finally, to evaluate the change detection accuracy of conventional methods and the threshold optimization algorithm, 90 polygons (15,543 pixels) were sampled, categorized as real change/unchanged zones, and defined as ground truth, from the interpretation of color aerial photo slides aided by the land cover maps to obtain the omission/commission errors and the Kappa coefficient of agreement. The results show that the threshold optimization is a suitable approach that can be applied for change detection analysis

    La Presencia Salesiana en Ecuador: Perspectivas históricas y sociales

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    Este libro recoge los resultados de un programa de investigación sobre las siguientes dimensiones de la presencia salesiana en el país: desarrollo comunitario, inclusión social, niñez y adolescencia; educación salesiana, con énfasis en la educación técnica; conformación de identidades e interculturalidad. Esta investigación fue realizada por un equipo de la Universidad Politécnica Salesiana en convenio con la Sociedad Salesiana en el Ecuador. Participaron profesionales que aportaron sus propias visiones desde diversas ciencias sociales (historia, sociología y antropología) y de la educación. Por lo tanto, se trata de una obra interdisciplinaria que busca profundizar el diálogo entre la herencia espiritual-pedagógica salesiana, la ciencia y las expectativas de los pueblos y culturas de hoy en momento de complejidad creciente de la sociedad ecuatoriana sujeta a transformaciones radicales cargadas de desafíos para la comunidad salesiana y la misma Iglesia

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    1er. Coloquio de educación para el diseño en la sociedad 5.0

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    Las memorias del 1er. Coloquio de Educación para el Diseño en la Sociedad 5.0 debenser entendidas como un esfuerzo colectivo de la comunidad de académicos de la División de Ciencias y Artes para el Diseño, que pone de manifiesto los retos y oportunidades que enfrenta la educación en diseño en un contexto de cambio acelerado y rompimiento de paradigmas.El evento se realizó el pasado mes de mayo de 2018 y se recibieron más de 50 ponencias por parte de las profesoras y profesores de la División.Las experiencias y/o propuestas innovadoras en cuanto a procesos de enseñanza y aprendizaje que presentan los autores en cada uno de sus textos son una invitación a reflexionar sobre nuestra situación actual en la materia, y emprender acciones en la División para continuar brindando una educación de calidad en diseño a nuestras alumnas, alumnos y la sociedad.Adicionalmente, se organizaron tres conferencias magistrales sobre la situación actual de la educación en Diseño y de las Instituciones de Educación Superior, impartidas por el Mtro. Luis Sarale, profesor de la Universidad Nacional de Cuyo en Mendoza (Argentina), y Presidente en su momento, de la Red de Carreras de Diseño en Universidades Públicas Latinoamericanas (DISUR), el Dr. Romualdo López Zárate, Rector de la Unidad Azcapotzalco, así como del Mtro. Luis Antonio Rivera Díaz, Jefe de Departamento de Teoría y Procesos del Diseño de la División de la Ciencias de la Comunicación y Diseño, en la Unidad Cuajimalpa de nuestra institución.La publicación de estas memorias son un esfuerzo divisional, organizado desde la Coordinación de Docencia Divisional y la Coordinación de Tecnologías del Aprendizaje, del Conocimiento y la Comunicación, para contribuir a los objetivos planteados en el documento ACCIONES:Agenda CyAD2021, en particular al eje de Innovación Educativa. Es necesario impulsar a todos los niveles de la División espacios de discusión orientados a reflexionar sobre el presente y futuro en la educación del diseñador, que contribuya a mejorar la calidad de la docencia y favorezca al fortalecimiento de los procesos de enseñanza y aprendizaje.Finalmente, extiendo un amplio reconocimiento a todos los miembros de la División que hicieron posible este evento, así como a todos los ponentes y participantes por compartir su conocimiento para que la División sea cada día mejor

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Preliminary phytochemical analysis and evaluation of antibacterial activity of extracts Disterigma Alaternoides

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    En el presente trabajo se llevó a cabo el estudio fitoquímico preliminar de la especie colombiana Disterigma alaternoides (Kunth) Nied. para identificar los metabolitos secundarios presentes, también se evaluó su actividad biológica, a la que se le pudo comprobar acción antibacteriana frente a dos cepas de bacterias Gram positiva Staphylococcus Aureus y Staphylococcus Epidermidis.In this paper we carried out the preliminary phytochemical study of Colombian species Disterigma alaternoides ( Kunth ) Nied . to identify secondary metabolites , their biological activity was also evaluated , which was able to verify antibacterial action against two strains of Gram positive bacteria Staphylococcus Aureus and Staphylococcus Epidermidis .Pontificia Universidad Javerian

    Topographic Correction to Landsat Imagery through Slope Classification by Applying the SCS + C Method in Mountainous Forest Areas

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    The aim of the topographic normalization of remotely sensed imagery is to reduce reflectance variability caused by steep terrain and thus improve further processing of images. A process of topographic correction was applied to Landsat imagery in a mountainous forest area in the south of Mexico. The method used was the Sun Canopy Sensor + C correction (SCS + C) where the C parameter was differently determined according to a classification of the topographic slopes of the studied area in nine classes for each band, instead of using a single C parameter for each band. A comparative, visual, and numerical analysis of the normalized reflectance was performed based on the corrected images. The results showed that the correction by slope classification improves the elimination of the effect of shadows and relief, especially in steep slope areas, modifying the normalized reflectance values according to the combination of slope, aspect, and solar geometry, obtaining reflectance values more suitable than the correction by non-slope classification. The application of the proposed method can be generalized, improving its performance in forest mountainous areas

    Evaluation of Unsupervised Change Detection Methods Applied to Landslide Inventory Mapping Using ASTER Imagery

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    Natural hazards include a wide range of high-impact phenomena that affect socioeconomic and natural systems. Landslides are a natural hazard whose destructive power has caused a significant number of victims and substantial damage around the world. Remote sensing provides many data types and techniques that can be applied to monitor their effects through landslides inventory maps. Three unsupervised change detection methods were applied to the Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster)-derived images from an area prone to landslides in the south of Mexico. Linear Regression (LR), Chi-Square Transformation, and Change Vector Analysis were applied to the principal component and the Normalized Difference Vegetation Index (NDVI) data to obtain the difference image of change. The thresholding was performed on the change histogram using two approaches: the statistical parameters and the secant method. According to previous works, a slope mask was used to classify the pixels as landslide/No-landslide; a cloud mask was used to eliminate false positives; and finally, those landslides less than 450 m2 (two Aster pixels) were discriminated. To assess the landslide detection accuracy, 617 polygons (35,017 pixels) were sampled, classified as real landslide/No-landslide, and defined as ground-truth according to the interpretation of color aerial photo slides to obtain omission/commission errors and Kappa coefficient of agreement. The results showed that the LR using NDVI data performs the best results in landslide detection. Change detection is a suitable technique that can be applied for the landslides mapping and we think that it can be replicated in other parts of the world with results similar to those obtained in the present work
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