Determinación de la activación de caspasas 3 y 7 durante el proceso de criopreservación de espermatozoides epididimarios de alpaca (Vicugna pacos) como marcadores de apoptosis tardía

Determina mediante citometría de flujo, la proporción de espermatozoides de alpaca con caspasas 3 y 7 activadas (apoptóticos) durante el proceso de criopreservación. Para esto se obtuvieron 23 muestras de epidídimo, en donde se evaluó la activación de las caspasas 3 y 7 utilizando CellEvent Caspase-3/7 Green Detection Reagent utilizando ensayos basados en citometría de flujo, antes y después del congelamiento. La prueba de t- Student pareada fue utilizada para comparar la proporción de espermatozoides apoptóticos antes y después de la criopreservación. Los porcentajes de espermatozoides de alpaca apoptóticos antes y después de la criopreservación fueron similares (36,2 ± 11,2% vs 36,7 ± 33,7%). Según nuestros resultados, la criopreservación no induciría apoptosis en los espermatozoides de alpaca; sin embargo, la alta desviación estándar encontrada después de la criopreservación se explica porque encontramos 2 maneras de afectar la calidad espermática, aquellas donde la apoptosis disminuyó aparentemente como resultado de la criopreservación (de 36,6 ± 9,1% a 1,5 ± 2.2%), y el grupo donde la apoptosis aumentó aparentemente después de la criopreservación (de 37,7 ± 13,0% a 64,0 ± 16,7%). Ambos grupos mostraron un porcentaje similar de espermatozoides viables y necróticos antes de la criopreservación; pero después de la criopreservación, mientras la viabilidad fue similar, encontramos 74,9 ± 14,5% (grupo con disminución de apoptosis) frente a 7,7 ± 5,0% (grupo con aumento de la apoptosis) de espermatozoides necróticos. Nuestros resultados indicarían que, en algunas muestras, los espermatozoides apoptóticos pasarían a ser necróticos debido a la criopreservación y por ello encontraríamos una relativa disminución de apoptosis, mientras que, en otro grupo de muestras, la criopreservación llevaría a aumentar la proporción de espermatozoides apoptóticos sin llegar a causar necrosis en elevada proporción. Se concluye que la criopreservación afecta la apoptosis en las muestras de espermatozoides de alpaca de diferentes maneras.Perú. Consejo Nacional de Ciencia y Tecnología. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt). Contrato 135–2020–FONDECYT y Proyecto PCONFIG2020 A2008038

Liderazgo pedagógico y desempeño docente en las instituciones educativas del distrito de Lurín, 2016

La presente investigación tuvo como objetivo determinar la relación entre el liderazgo pedagógico y el desempeño docente y surge como respuesta a la problemática de la Institución Educativa descrita. Obedece a un enfoque cuantitativo, tipo básico y diseño no experimental, correlacional de corte transversal, habiéndose utilizado cuestionarios con una escala de Likert como instrumentos de recolección de datos que se aplicó a una muestra de 114 docentes de las Instituciones Educativas de Lurín., y se utilizó el coeficiente de correlación de Spearman, se llegó a la siguiente conclusión: El liderazgo pedagógico sí se relaciona de manera directa y alta con el desempeño docente en las Instituciones Educativas del distrito de Lurín, 2016; habiéndose obtenido un coeficiente de correlación de Spearman igual a 0,77

The AFLOW Fleet for Materials Discovery

The traditional paradigm for materials discovery has been recently expanded to incorporate substantial data driven research. With the intent to accelerate the development and the deployment of new technologies, the AFLOW Fleet for computational materials design automates high-throughput first principles calculations, and provides tools for data verification and dissemination for a broad community of users. AFLOW incorporates different computational modules to robustly determine thermodynamic stability, electronic band structures, vibrational dispersions, thermo-mechanical properties and more. The AFLOW data repository is publicly accessible online at aflow.org, with more than 1.7 million materials entries and a panoply of queryable computed properties. Tools to programmatically search and process the data, as well as to perform online machine learning predictions, are also available.Comment: 14 pages, 8 figure

{SelfPose}: {3D} Egocentric Pose Estimation from a Headset Mounted Camera

We present a solution to egocentric 3D body pose estimation from monocular images captured from downward looking fish-eye cameras installed on the rim of a head mounted VR device. This unusual viewpoint leads to images with unique visual appearance, with severe self-occlusions and perspective distortions that result in drastic differences in resolution between lower and upper body. We propose an encoder-decoder architecture with a novel multi-branch decoder designed to account for the varying uncertainty in 2D predictions. The quantitative evaluation, on synthetic and real-world datasets, shows that our strategy leads to substantial improvements in accuracy over state of the art egocentric approaches. To tackle the lack of labelled data we also introduced a large photo-realistic synthetic dataset. xR-EgoPose offers high quality renderings of people with diverse skintones, body shapes and clothing, performing a range of actions. Our experiments show that the high variability in our new synthetic training corpus leads to good generalization to real world footage and to state of theart results on real world datasets with ground truth. Moreover, an evaluation on the Human3.6M benchmark shows that the performance of our method is on par with top performing approaches on the more classic problem of 3D human pose from a third person viewpoint.Comment: 14 pages. arXiv admin note: substantial text overlap with arXiv:1907.1004

Effects of mitochondrial poisons on glutathione redox potential and carotid body chemoreceptor activity

Producción CientíficaLowoxygen sensing in chemoreceptor cells involves the inhibition of specific plasma membrane K+ channels, suggesting that mitochondria-derived reactive oxygen species (ROS) link hypoxia to K+ channel inhibition, subsequent cell depolarization and activation of neurotransmitter release.We have used several mitochondrial poisons, alone and in combination with the antioxidant N-acetylcysteine (NAC), and quantify their capacity to alter GSH/GSSG levels and glutathione redox potential (EGSH) in rat diaphragm. Selected concentrations of mitochondrial poisons with or without NAC were tested for their capacity to activate neurotransmitter release in chemoreceptor cells and to alter ATP levels in intact rat carotid body (CB).We found that rotenone (1 M), antimycin A (0.2 g/ml) and sodium azide (5mM) decreased EGSH; NAC restored EGSH to control values. At those concentrations mitochondrial poisons activated neurotransmitter release from CB chemoreceptor cells and decreased CB ATP levels, NAC being ineffective to modify these responses. Additional experiments with 3-nitroprionate (5 mM), lower concentrations of rotenone and dinitrophenol revealed variable relationships between EGSH and chemoreceptor cell neurotransmitter release responses and ATP levels. These findings indicate a lack of correlation between mitochondrialgenerated modifications of EGSH and chemoreceptor cells activity. This lack of correlation renders unlikely that alteration of mitochondrial production of ROS is the physiological pathway chemoreceptor cells use to signal hypoxia

Chemoreception in the context of the general biology of ROS

Producción CientíficaSuperoxide anion is the most important reactive oxygen species (ROS) primarily generated in cells. The main cellular constituents with capabilities to generate superoxide anion areNADPHoxidases and mitochondrial respiratory chain. The emphasis of our article is centered in critically examining hypotheses proposing that ROS generated by NADPH oxidase and mitochondria are key elements in O2-sensing and hypoxic responses generation in carotid body chemoreceptor cells. Available data indicate that chemoreceptor cells express a specific isoform of NADPH oxidase that is activated by hypoxia; generated ROS acting as negative modulators of the carotid body (CB) hypoxic responses. Literature is also consistent in supporting that poisoned respiratory chain can produce high amounts of ROS, making mitochondrial ROS potential triggers-modulators of the CB activation elicited by mitochondrial venoms. However, most data favour the notion that levels of hypoxia, capable of strongly activating chemoreceptor cells, would not increase the rate of ROS production in mitochondria, making mitochondrial ROS unlikely triggers of hypoxic responses in the CB. Finally, we review recent literature on heme oxygenases from two perspectives, as potential O2-sensors in chemoreceptor cells and as generators of bilirubin which is considered to be a ROS scavenger of major quantitative importance in mammalian cells

Defining a strategy to perform life-tests with analog devices

Unlike for memory elements inside integrated circuits, scarce life tests have been performed to study single event transients in discrete analog devices. The reason is that life tests require a large amount of samples to be stored for having enough data allowing statistical conclusions and, usually, single event transients are captured by means of oscilloscopes. In this paper, we propose a strategy to carry out life tests in analog voltage comparators by means of digital programmable device that can detect anomalous pulses in the voltage comparator. Besides, the idea on which this kind of tests relies can be extended to be used with other families of analog devices, such as operational amplifiers, voltage references, etc

Significance of ROS in oxygen sensing in cell systems with sensitivy to ohysiological hypoxia

Reactive oxygen species (ROS) are oxygen-containing molecular entities which are more potent and effective oxidizing agents than is molecular oxygen itself. With the exception of phagocytic cells, where ROS play an important physiological role in defense reactions, ROS have classically been considered undesirable byproducts of cell metabolism, existing several cellular mechanisms aimed to dispose them. Recently, however, ROS have been considered important intracellular signaling molecules, which may act as mediators or second messengers in many cell functions. This is the proposed role for ROS in oxygen sensing in systems, such as carotid body chemoreceptor cells, pulmonary artery smooth muscle cells, and erythropoietin-producing cells. These unique cells comprise essential parts of homeostatic loops directed to maintain oxygen levels in multicellular organisms in situations of hypoxia. The present article examines the possible significance of ROS in these three cell systems, and proposes a set of criteria that ROS should satisfy for their consideration as mediators in hypoxic transduction cascades. In none of the three cell types do ROS satisfy these criteria, and thus it appears that alternative mechanisms are responsible for the transduction cascades linking hypoxia to the release of neurotransmitters in chemoreceptor cells, contraction in pulmonary artery smooth muscle cells and erythropoietin secretion in erythropoietin producing cells

Plan de negocio para la implementaci?n de una soluci?n tecnol?gica que proporcione a los pacientes una historia cl?nica dental ?nica a trav?s de Blockchain

En el Per? no existe una soluci?n digital donde un paciente pueda encontrar la oferta de servicios dentales que mejor se le acomode de acuerdo a recomendaciones, cercan?a y disponibilidad de citas. A esto se le suma que cada vez que un paciente tiene tantas historias cl?nicas dentales como consultorios haya visitado. Es por ello que se propone un modelo de negocio de doble cara que permita, por un lado, hacer due?o al paciente de una historia cl?nica dental unificada y por el otro, ofrezca a los due?os de consultorios dentales una soluci?n integral para la gesti?n de sus consultorios y todo integrado en una misma plataforma digital que conecte pacientes con consultorios dentales