176 research outputs found
Industrial Fieldbus Improvements in Power Distribution and Conducted Noise Immunity With No Extra Costs
Industrial distributed control continues the move
toward networks at all levels. At lower levels, control networks
provide flexibility, reliability, and low cost, although perhaps the
simplest but most important advantage is the reduced volume
of wiring. Powered fieldbuses offer particular notable benefits in
system wiring simplification. Nevertheless, very few papers are
dealing with the potentials and limitations in power distribution
through the bus cable. Only a few of the existent fieldbus standards
consider this possibility but often simply as an option without
enough technical specifications. In fact, nobody talks about it, but
power distribution through the bus and conducted noise disturbances
are strongly related. This paper points out and analyzes
these limitations and proposes a new low-cost fieldbus physical
layer that enlarges power distribution capability of the bus and
improves system robustness. We show an industrial application
on water desalination plants and the very good results obtained
owing to the fieldbus. Finally, we present electromagnetic compatibility
test results that verify improvements against electrical fast
transients on the sensor/actuator connection side as disturbances
usually encountered in harsh-environment industrial applications
Electronic Technology Teaching Using Manufacturer’s Datasheets
Se propone una metodología de enseñanza para cursos de tecnología electrónica. El método incluye un adecuado balance entre los conceptos básicos necesarios y la información entregada en hojas de datos y catálogos de los fabricantes. Usando este nuevo enfoque, se analiza la enseñanza de conceptos y aplicaciones de diodos semiconductores de rectificación. La metodología ha mostrado ser efectiva y debería ser incorporada en textos de tecnología electrónica.A teaching methodology for electronic technology courses is proposed. The method includes an appropriate balance between the necessary basic concepts and the information provided in the manufactures datasheets and catalogs. Using this new approach, the teaching of concepts and applications of rectification superconductor diodes is analyzed. The methodology has shown to be effective and should be included in electronic technology books
Diseño y análisis de redes homeostáticas adaptativas
Conseguir dotar a un agente artificial con la capacidad de adaptabilidad presente en los seres vivos le proporcionarı́a habilidades necesarias para realizar tareas para las que no ha sido entrenado o para las que se le ha entrenado pero en un entorno cambiante o con incertidumbre. En este trabajo nos interesaremos, desde una perspectiva ingenieril, por unos de los sistemas de autoregulación presentes en los organismos vivos conocidos como mecanismos homeostáticos, que están en la base de ciertas capacidades de adaptación. En particular, se ha partido del diseño e implementación de un agente homeostático basado en redes neuronales recurrentes de tiempo continuo con capacidad de fototaxis (búsqueda y acercamiento a una serie de luces en un espacio). Este agente se corresponde con el mejor candidato de una cierta población, seleccionado mediante un algorı́tmo genético. La peculiaridad del mismo, es que despliega comportamiento homeostático a través de mecanismos de plasticidad, que le permiten modificar sus variables internas para alcanzar un estado estable y mantenerse en el mismo aunque se vea sometido a perturbaciones externas. Una vez obtenido el agente con las propiedades de fototaxis y plasticidad homeostática, se ha buscado dotar al mismo de capacidades para que emerjan comportamientos sociales con el fin de analizar cómo interacciona en situaciones donde hay más de un agente involucrado. El comportamiento social se ha añadido siguiendo dos aproximaciones diferentes. La primera, asume que las capacidades del agente son aditivas. Es decir, que el agente tras ser capaz de navegar y orientarse hacia un foco de luz (o comida), necesitarı́a una nueva estructura neuronal con la que codificar otra capacidad novedosa (en este caso, coordinación social). Se modelará el sistema con dos mecanismos independientes en el controlador del sistema, uno para la navegación y otro para el aspecto social. La segunda, defiende que el comportamiento social es una caracterı́stica estructural del sistema. Por tanto, una nueva capacidad atraviesa (en ocasiones se dice que “percola”) las capacidades previas, reestructurando el controlador neuronal del agente en su conjunto. El objetivo es comparar estas dos aproximaciones y sacar conclusiones sobre ello mediante experimentos en los que varios agentes tienen que interactuar de manera social para la consecución de un objetivo
V-Myc immortalizes human neural stem cells in the absence of pluripotency-associated traits
© 2015 Pino-Barrio et al. A better understanding of the molecular mechanisms governing stem cell self-renewal will foster the use of different types of stem cells in disease modeling and cell therapy strategies. Immortalization, understood as the capacity for indefinite expansion, is needed for the generation of any cell line. In the case of v-myc immortalized multipotent human Neural Stem Cells (hNSCs), we hypothesized that v-myc immortalization could induce a more dedifferentiated state in v-myc hNSC lines. To test this, we investigated the expression of surface, biochemical and genetic markers of stemness and pluripotency in v-myc immortalized and control hNSCs (primary precursors, that is, neurospheres) and compared these two cell types to human Embryonic Stem Cells (hESCs) and fibroblasts. Using a Hierarchical Clustering method and a Principal Component Analysis (PCA), the v-myc hNSCs associated with their counterparts hNSCs (in the absence of v-myc) and displayed a differential expression pattern when compared to hESCs. Moreover, the expression analysis of pluripotency markers suggested no evidence supporting a reprogramming-like process despite the increment in telomerase expression. In conclusion, v-myc expression in hNSC lines ensures self-renewal through the activation of some genes involved in the maintenance of stem cell properties in multipotent cells but does not alter the expression of key pluripotency-associated genes.Spanish Ministry of Economy and Competitiveness (PLE2009–0101, SAF2010–17167); Comunidad Autónoma Madrid (S2011—BMD—2336); Instituto Salud Carlos III (RETICS TerCel, RD12/0019/0013) and European Union (Excell, NMP4—SL—2008–214706); (to PM): Instituto Salud Carlos III (RETICS TerCel, RD12/0019/0006; FISPeer Reviewe
V-Myc immortalizes human neural stem cells in the absence of pluripotency-associated traits
The data discussed in
this publication have been deposited in NCBI’s Gene
Expression Omnibus (GEO) and are accessible
through GEO Series accession number GSE63710A better understanding of the molecular mechanisms governing stem cell self-renewal
will foster the use of different types of stem cells in disease modeling and cell therapy strategies.
Immortalization, understood as the capacity for indefinite expansion, is needed for the
generation of any cell line. In the case of v-myc immortalized multipotent human Neural
Stem Cells (hNSCs), we hypothesized that v-myc immortalization could induce a more dedifferentiated
state in v-myc hNSC lines. To test this, we investigated the expression of surface,
biochemical and genetic markers of stemness and pluripotency in v-myc immortalized
and control hNSCs (primary precursors, that is, neurospheres) and compared these two
cell types to human Embryonic Stem Cells (hESCs) and fibroblasts. Using a Hierarchical
Clustering method and a Principal Component Analysis (PCA), the v-myc hNSCs associated
with their counterparts hNSCs (in the absence of v-myc) and displayed a differential expression
pattern when compared to hESCs. Moreover, the expression analysis of
pluripotency markers suggested no evidence supporting a reprogramming-like process despite
the increment in telomerase expression. In conclusion, v-myc expression in hNSC
lines ensures self-renewal through the activation of some genes involved in the maintenance
of stem cell properties in multipotent cells but does not alter the expression of key
pluripotency-associated genesThis work was supported by grants from (to
AMS): Spanish Ministry of Economy and
Competitiveness (PLE2009–0101, SAF2010–17167),
Comunidad Autónoma Madrid (S2011—BMD—
2336), Instituto Salud Carlos III (RETICS TerCel,
RD12/0019/0013) and European Union (Excell,
NMP4—SL—2008–214706); (to PM): Instituto Salud
Carlos III (RETICS TerCel, RD12/0019/0006; FIS
P110/0449), ERANEt ISCIII—Fondos FEDER (PI12/
03112) and the Spanish Association of Cancer
Research (CIMEN2011). MJPB was funded by
MINECO (PLE2009–0101) and Instituto Salud Carlos
III (RETICS TerCel, RD06/0019/0023). This work was
also supported by an institutional grant from
Fundación Ramón Areces to the Center of Molecular
Biology Severo Ochoa. PM lab is supported by:
Instituto de Salud Carlos III (ISCIII; E-Rare-2 Call
PI12/03112), Ministerio de Economía y
Competitividad (MINECO; SAF2013-43065),
Generalitat de Catalunya (SGR330) and Obra Social
La Caixa-Fundaciò Josep Carrera
Análisis de fractura de bulones de trunnion pin de turbina de gas de una generadora termoeléctrica
El trabajo consiste en realizar el análisis de fractura y la caracterización del material de dos bulones que fallaron en servicio en el soporte de una turbina de gas pertenecientes a una central de generación termoeléctrica. Para ello se plantea la realización del análisis fractográfico y la caracterización microestructural mediante microscopía óptica y electrónica de barrido analítica, como así también la caracterización de las propiedades mecánicas y composición química del material. A partir de los análisis realizados se considera que las fracturas de los dos bulones ocurrieron por un mecanismo de corrosión-fatiga, a causa de un ataque corrosivo por oxígeno en solución acuosa salina. Los bulones analizados se corresponden con aceros de medio carbono al Mo del tipo de los especificados SAE J429, cumpliendo con el grado 8.Facultad de Ingenierí
The Challenge of Assessing Microcephaly in the Context of the Zika Virus Epidemic
The present article examines the impact of the current
limitations of the microcephaly definition in the context of the
Zika virus outbreak. It highlights its dependence on the method
used for determining gestational age and other anthropometric
parameters, and includes original results of prevalence of
microcephaly in four countries from two different continents
(Mozambique, Brazil, Guatemala and Colombia). Alternative
definitions of microcephaly are proposed to allow the
identification of true cases of microcephaly in a more accurate
manner
The role of Xpert MTB/RIF in diagnosing pulmonary tuberculosis in post-mortem tissues
The extent to which the Xpert MTB/RIF (Gene Xpert) contributes
to tuberculosis (TB) diagnosis in samples other than sputum and
cerebrospinal fluid remains uncertain. We aimed to assess the
role of Xpert MTB/RIF for detecting M. tuberculosis in
post-mortem tissues. We conducted a study among 30 complete
diagnostic autopsies (CDA) performed at the Maputo Central
Hospital (Mozambique). Lung tissues were screened for TB in all
cases. In addition other tissues were tested when compatible
lesions were identified in the histological exam. We used
in-house real time PCR and LAMP assays to confirm the presence
of M. tuberculosis DNA. The diagnosis of tuberculosis at death
was established based on microbiological and histopathological
results. Eight out of 30 cases (26.7%) were diagnosed of
tuberculosis. Xpert had a sensitivity to detect TB in lung
tissue of 87.5% (95% CI 47.3-99.7) and a specificity of 95.7%
(95% CI: 78.1-99.9). In-house DNA amplification methods and
Xpert showed 93.6% concordance for lung tissue and 100%
concordance for brain and liver tissues. The final cause of
death was attributable to tuberculosis in four cases. Xpert
MTB/RIF may represent a valuable, easy-to perform technique for
post-mortem TB diagnosis
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