1,282 research outputs found

    Cancer Reduces Transcriptome Specialization

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    A central goal of cancer biology is to understand how cells from this family of genetic diseases undergo specific morphological and physiological changes and regress to a de-regulated state of the cell cycle. The fact that tumors are unable to perform most of the specific functions of the original tissue led us to hypothesize that the degree of specialization of the transcriptome of cancerous tissues must be less than their normal counterparts. With the aid of information theory tools, we analyzed four datasets derived from transcriptomes of normal and tumor tissues to quantitatively test the hypothesis that cancer reduces transcriptome specialization. Here, we show that the transcriptional specialization of a tumor is significantly less than the corresponding normal tissue and comparable with the specialization of dedifferentiated embryonic stem cells. Furthermore, we demonstrate that the drop in specialization in cancerous tissues is largely due to a decrease in expression of genes that are highly specific to the normal organ. This approach gives us a better understanding of carcinogenesis and offers new tools for the identification of genes that are highly influential in cancer progression

    Rescate de embriones en híbridos intergenéricos Helianthus annuus x Tithonia rotundifolia

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    In this research an in vitro technique was developed for production and propagation of intergeneric hybrids from immature seeds produced by crossing the domestic sunflower Helianthus annuus and the wild species Tithonia rotundifolia (Mill.) S. F. Blake. For embryo rescue in tissue culture the greatest success was obtained with the sequential use of three Murashige-Skoog based media: a) with amino acids and growth regulator BAP for germination, b) without amino acids and with BAP for micropropagation, and c) without vitamins and growth regulator ANA for root development. The amino acids were added as a source of organic nitrogen. From a single seedling a total of 130 healthy plantlets were obtained. Twenty of them were taken for acclimatization, and only one reached an incomplete flowering stage. Therefore, standardizing acclimatization conditions is still required. In particular, it is necessary to establish treatments that allow a clear definition of the specific conditions for the acclimatization of the hybrid, through the test of different substrate mixtures and nutritive solutions under controlled environmental conditions. It is recommended to try the use of retardants and amino acids, as well as modifications in light intensity.En esta investigación se desarrolló una técnica in vitro para producir y propagar híbridos intergenéricos a partir de semillas inmaduras producto del cruzamiento del girasol cultivado Helianthus annuus L. con la especie silvestre Tithonia rotundifolia (Mill.) S. F. Blake. Para el rescate de embriones inmaduros en cultivo de tejidos el mayor éxito se obtuvo con el uso secuencial de tres medios basados en el de Murashige-Skoog: a) con adición de aminoácidos y el regulador de crecimiento BAP para germinación, b) sin aminoácidos y con BAP para micropropagación, y c) sin vitaminas y con el regulador de crecimiento ANA para enraizamiento. Los aminoácidos se agregaron como fuente de nitrógeno orgánico. A partir de una plántula se lograron obtener 130 en buenas condiciones de sanidad. Veinte de ellas se llevaron a aclimatación, y solamente una generó botones y llegó a floración inconclusa, por lo que aún se requiere estandarizar las condiciones de aclimatación. En particular, se necesita establecer tratamientos que permitan definir con claridad las condiciones específicas para aclimatar el híbrido, a través de la prueba de diferentes mezclas de sustratos y soluciones nutritivas bajo condiciones ambientales controladas. Se recomienda probar el manejo de retardantes y aminoácidos, así como realizar modificaciones en la intensidad de luz

    Outstanding nonlinear optical properties of methylammonium- and Cs-PbX3 (X = Br, I, and Br–I) perovskites: Polycrystalline thin films and nanoparticles

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    Metal Halide Perovskites (MHPs) have arisen as promising materials to construct cost-effective photovoltaic and light emission devices. The study of nonlinear optical properties of MHPs is necessary to get similar success in nonlinear photonic devices, which is practically absent in the literature. The determination of the third order nonlinear coefficients is typically done by the Z-scan technique, which is limited by the scattering of polycrystalline thin films. In this work, we have studied nonlinear optical properties of polycrystalline CH3NH3PbX3 (MAPbX3) thin films and colloidal CsPbX3 nanoparticles with three different bandgaps (X3 = I3, Br3, and Br1.5I1.5). Their bright generation of photoluminescence under infrared illumination demonstrates an excellent efficiency of multiphoton absorption. The nonlinear absorption coefficient ( ) was studied by analyzing the transmitted light through the samples, observing the expected Eg −3 dependence with values as high as = 1500 cm/GW. In addition, we proposed the use of a modified Z-scan technique with imaging processing to analyze the nonlinear refraction coefficient (n2) under the laser damage threshold. Our experimental data agree quite well with theoretical predictions, demonstrating the accuracy of the method and potential applications to other thin films. Moreover, n2 parameter reaches values of 3.5 cm2/GW, indicating the suitability of MHPs for nonlinear photonics

    El índice Ka: un nuevo algoritmo para analizar los componentes de la superficie terrestre en imágenes de satélite

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    El cambio del paisaje de la superficie terrestre, su composición y estructura, ocurrido por causas di- versas, ha estado en la mira de toda la humanidad. Se han desarrollado diversas formas para entender- los y la sensoría remota es lo más reciente y nove- doso para tener un conocimiento rápido de gran- des extensiones. En este estudio se ha desarrollado un nuevo algoritmo para medir estos cambios, así como para identificar valores espectrales de espe- cies de coníferas, utilizando imágenes del satélite Landsat7 ETM+. Los resultados muestran un gran potencial del índice Ka para detectar los diferentes componentes superficiales y su variabilidad debi- do a efectos naturales o antropológicos, etc. The change in the landscape of the terrestrial surface, its composition, and its structure, caused by many factors, has been in the aim of all humanity. Diverse forms have been developed in order to understand them, the sensory remote being the most recent and novel thing in acquiring fast knowledge of large extensions. In this study a new algorithm has been developed to measure these changes, as well as to identify ghastly values of coniferous species using images of the satellite Landsat7 ETM+. The results show a great potential of the Ka index in detecting the different superfi- cial components and its variability due to natural effects or due to man

    Transcriptome analyses throughout chili pepper fruit development reveal novel insights into the domestication process

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    Chili pepper (Capsicum spp.) is an important crop, as well as a model for fruit development studies and domestication. Here, we performed a time-course experiment to estimate standardized gene expression profiles with respect to fruit development for six domesticated and four wild chili pepper ancestors. We sampled the transcriptomes every 10 days from flowering to fruit maturity, and found that the mean standardized expression profiles for domesticated and wild accessions significantly differed. The mean standardized expression was higher and peaked earlier for domesticated vs. wild genotypes, particularly for genes involved in the cell cycle that ultimately control fruit size. We postulate that these gene expression changes are driven by selection pressures during domestication and show a robust network of cell cycle genes with a time shift in expression, which explains some of the differences between domesticated and wild phenotypes

    Diseño de un plan estratégico para fortalecer las acciones del programa de prevención del delito "Futuro Colombia" - Fiscalía General de la Nación.

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    La práctica de los diferentes programas sociales educativos marca un enfoque sectorizado debido a las diferencias socioculturales que existen en Colombia, intentando solucionar problemas delictivos como hurto, homicidio, bullying, entre otros; dependiendo de la zona, región, municipio o ciudad, articulándolo a su vez con las diferentes problemáticas sociales, culturales, familiares y personales de raíz y fondo que se encuentran interrelacionadas. Es necesario señalar que las conductas y comportamientos delictivos traen consigo una serie de connotaciones tanto familiares como sociales, es por ello que los diferentes factores de riesgo obligan a estas personas a caer en acciones delictivas desde muy temprana edad. En Colombia, la Fiscalía General de la nación, en fecha de 1993 lanzo el programa “Futuro Colombia” como una propuesta de servicio a la comunidad, para la prevención del delito en la población en general con énfasis en la delincuencia y violencia juvenil

    La vid silvestre en México. Actualidades y potencial

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    En ocho capítulos se aborda el estado del arte de la vid silvestre en MéxicoEl estudio de las especies vegetales nativas de México representa un reto que cada día más investigadores mexicanos asumen. Durante muchos años, el apoyo a la investigación pública ha sido mínimo; desde el punto de vista agronómico es insuficiente para avanzar a la velocidad que requiere nuestro país para afrontar problemas de producción y distribución de alimentos. Por esa razón, entre otras, me es grato presentar esta obra que compila parte de los trabajos de la Red de Vid Silvestre patrocinada por el Sistema Nacional de Recursos Fitogenéticos (sinarefi) dependiente de la sagarpa; trabajos apuntalados por investigadores que sin pertenecer a la red han colaborado en el estudio de las plantas del género Vitis. En este libro se muestra el potencial del país para aprovechar el recurso vid, empleado desde antes de la conquista española por nativos mexicanos que conocían sus bondades. Es necesario continuar el avance en el conocimiento de este recurso, por ello el presente libro pretende invitar a toda persona interesada en contribuir con el rescate y conservación de las vides mexicanas. Los autores y editores, así como las instituciones en donde laboramos y aquellas que patrocinan estas investigaciones, esperamos se cumpla este objetivo y que el lector, alumno, profesor, investigador, público en general, disfrute esta lectura y, sobre todo, se interese en el recurso VitisSEP, SINAREFI, UAEME

    Detection and Tertiary Treatment Technologies of Poly-and Perfluoroalkyl Substances in Wastewater Treatment Plants

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    PFAS are a very diverse group of anthropogenic chemicals used in various consumer and industrial products. The properties that characterize are their low degradability as well as their resistance to water, oil and heat. This results in their high persistence in the environment and bioaccumulation in different organisms, causing many adverse effects on the environment as well as in human health. Some of their effects remain unknown to this day. As there are thousands of registered PFAS, it is difficult to apply traditional technologies for an efficient removal and detection for all. This has made it difficult for wastewater treatment plants to remove or degrade PFAS before discharging the effluents into the environment. Also, monitoring these contaminants depends mostly on chromatography-based methods, which require expensive equipment and consumables, making it difficult to detect PFAS in the environment. The detection of PFAS in the environment, and the development of technologies to be implemented in tertiary treatment of wastewater treatment plants are topics of high concern. This study focuses on analyzing and discussing the mechanisms of occurrence, migration, transformation, and fate of PFAS in the environment, as well the main adverse effects in the environment and human health. The following work reviews the recent advances in the development of PFAS detection technologies (biosensors, electrochemical sensors, microfluidic devices), and removal/degradation methods (electrochemical degradation, enzymatic transformation, advanced oxidation, photocatalytic degradation). Understanding the risks to public health and identifying the routes of production, transportation, exposure to PFAS is extremely important to implement regulations for the detection and removal of PFAS in wastewater and the environment.This work is part of the project entitled “Contaminantes emergentes y prioritarios en las aguas reutilizadas en agricultura: riesgos y efectos en suelos, producción agrícola y entorno ambiental” funded by CSIC-Tecnológico de Monterrey under i-Link + program (LINKB20030).Peer reviewe
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