1,720,957 research outputs found
Evaluación del efecto de citoquinas sobre células progenitoras neurales en ratones adultos.
No full textLa neurogénesis adulta, originada por las células progenitoras neurales (NPCs), ha sido observada en dos regiones del cerebro: la zona subventricular (SVZ) y la zona subgranular (SGZ) en el hipocampo. El hipocampo es una estructura involucrada en el aprendizaje y las memorias asociativas y espaciales. Las NPCs se caracterizan por autorrenovar su población celular a través de la proliferación y de generar las células del linaje neural, como neuronas, astrocitos y oligodendrocitos. Los nichos neurogénicos están altamente regulados por varios factores, entre ellos, las citoquinas provenientes tanto del sistema inmune (SI) como del SNC. Así, las citoquinas han sido implicadas en procesos de proliferación, supervivencia, diferenciación y maduración de las NPCs relacionados con el aprendizaje y la memoria. Además, el IFN-γ, IL-1β e IL-6 han sido implicadas en desordenes psiquiátricos. Estudios previos en nuestro laboratorio demostraron que ratones Balb/c hembras expuestas a un modelo de estrés crónico presentaron una menor capacidad de aprendizaje y memoria y disminución de la neurogénesis, que se correlacionaron con alteraciones en el balance Th1/Th2. En este trabajo, nos planteamos como objetivo la puesta a punto del cultivo in vitro de NPCs hipocampales y la evaluación del efecto de las citoquinas IFN-γ, IL-1β, IL-4 e IL-6 sobre la proliferación y diferenciación de estas células. Observamos que el IFN-γ induce una disminución en la proliferación de las NPCs en un rango de concentraciones de entre 1 y 50 ng/mL y no afectó significativamente la diferenciación de las NPCs. No encontramos diferencias significativas en cuanto a la proliferación y diferenciación de las NPCs estimuladas con distintas concentraciones de IL-1β ni IL-4. La IL-6 indujo efectos opuestos sobre la proliferación de manera dosis dependiente. NPCs estimuladas con 1 ng/mL de IL-6 aumentó la proliferación mientras que 50 ng/mL de IL-6 la redujo significativamente. Más estudios son necesarios para determinar el papel de las citoquinas sobre los procesos de proliferación y diferenciación de las NPCs adultas. Estos resultados podrían aportar herramientas para contribuir en un futuro a desarrollar posibles terapias contra patologías relacionadas con déficit cognitivos.Fil: Moroni, Alejandro David. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Escuela de Ciencias Agrarias, Naturales y Ambientales; Argentina.Licenciatura en Genétic
Reconocimiento automático de marcadores biológicos a partir de técnicas de Visión e Inteligencia artificial
Get PDFEn los últimos años, el avance respecto a
la adquisición de grandes cantidades de
imágenes de microscopía, ha hecho
posible que el análisis digital de imágenes
desarrolle herramientas capaces de obtener
información de manera automática. Esta
automatización y digitalización de
procesos ha contribuido significativamente
a reducir tanto los tiempos como los
errores asociados con las técnicas
manuales. El objetivo de la presente
investigación es el diseño de un modelo
basado en visión e inteligencia artificial
que permita automatizar procesos de
laboratorio, con la capacidad de
segmentar y caracterizar automáticamente
marcadores celulares en imágenes de
microscopía. Estos resultados tienen el
objetivo de reducir los tiempos dedicados
al análisis visual de imágenes, generar
información de soporte a la toma de
decisiones y aportar herramientas para el
especialista genetista.Fil: Pérez, Gabriel. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Instituto de Investigación y Transferencia en Tecnología; Argentina.Fil: Russo, Claudia. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Instituto de Investigación y Transferencia en Tecnología; Argentina.Fil: Palumbo, María Laura. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones Básicas y Aplicadas; Argentina.Fil: Moroni, Alejandro David. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones Básicas y Aplicadas; Argentina.Con referat
Deep Learning-Based Instance Segmentation of Neural Progenitor Cell Nuclei in Fluorescence Microscopy Images
Get PDFIn this work, a Deep Learning-based machine vision model was devel-
oped for the detection, segmentation and counting of Neural Progenitor Cell nuclei
from fluorescence microscopy images. The cells were obtained from adult mice
and cultivated in vitro, with cellular nuclei labeled using DAPI dye. Convolu-
tional neural networks for instance segmentation, specifically the Mask R-CNN
model with ResNet-50 and ResNet-101 backbones, were trained to recognize the
nuclei, and their results were evaluated. Nuclei labeling was implemented semi-
automatically, applying a Superpixel technique and then refining the segmentations
from a manual process, also using a pre-trained model, which allowed to assem-
ble a dataset of 66 images with 6392 labels in total. The results obtained with the
Resnet-50 backbone show that there is an effectiveness of 98.6% for between the
specialist count and model-predicted count, in addition to having an mAP50 of
98.0%. This approach has the potential to significantly reduce the time and effort
required to analyze large image sets, which is especially useful in studies that
require repetitive and detailed cellular analysis.Fil: Pérez, Gabriel. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Instituto de Investigación y Transferencia en Tecnología; Argentina.Fil: Russo, Claudia. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Instituto de Investigación y Transferencia en Tecnología; Argentina.Fil: Palumbo, María Laura. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones Básicas y Aplicadas; Argentina.Fil: Moroni, Alejandro David. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones Básicas y Aplicadas; Argentina.Con referat
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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