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Search Results: 1 - 10 of 193193 matches for " Lisbell D. Estrada "
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EphA4 Activation of c-Abl Mediates Synaptic Loss and LTP Blockade Caused by Amyloid-β Oligomers
Lina M. Vargas, Nancy Leal, Lisbell D. Estrada, Adrian González, Felipe Serrano, Katherine Araya, Katia Gysling, Nibaldo C. Inestrosa, Elena B. Pasquale, Alejandra R. Alvarez
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0092309
Abstract: The early stages of Alzheimer's disease are characterised by impaired synaptic plasticity and synapse loss. Here, we show that amyloid-β oligomers (AβOs) activate the c-Abl kinase in dendritic spines of cultured hippocampal neurons and that c-Abl kinase activity is required for AβOs-induced synaptic loss. We also show that the EphA4 receptor tyrosine kinase is upstream of c-Abl activation by AβOs. EphA4 tyrosine phosphorylation (activation) is increased in cultured neurons and synaptoneurosomes exposed to AβOs, and in Alzheimer-transgenic mice brain. We do not detect c-Abl activation in EphA4-knockout neurons exposed to AβOs. More interestingly, we demonstrate EphA4/c-Abl activation is a key-signalling event that mediates the synaptic damage induced by AβOs. According to this results, the EphA4 antagonistic peptide KYL and c-Abl inhibitor STI prevented i) dendritic spine reduction, ii) the blocking of LTP induction and iii) neuronal apoptosis caused by AβOs. Moreover, EphA4-/- neurons or sh-EphA4-transfected neurons showed reduced synaptotoxicity by AβOs. Our results are consistent with EphA4 being a novel receptor that mediates synaptic damage induced by AβOs. EphA4/c-Abl signalling could be a relevant pathway involved in the early cognitive decline observed in Alzheimer's disease patients.
Fluid-solid transition in hard hyper-sphere systems
C. D. Estrada,M. Robles
Physics , 2010, DOI: 10.1063/1.3530780
Abstract: In this work we present a numerical study, based on molecular dynamics simulations, to estimate the freezing point of hard spheres and hypersphere systems in dimension D = 4, 5, 6 and 7. We have studied the changes of the Radial Distribution Function (RDF) as a function of density in the coexistence region. We started our simulations from crystalline states with densities above the melting point, and moved down to densities in the liquid state below the freezing point. For all the examined dimensions (including D = 3) it was observed that the height of the first minimum of the RDF changes in an almost continuous way around the freezing density and resembles a second order phase transition. With these results we propose a numerical method to estimate the freezing point as a function of the dimension D using numerical fits and semiempirical approaches. We find that the estimated values of the freezing point are very close to previously reported values from simulations and theoretical approaches up to D = 6 reinforcing the validity of the proposed method. This was also applied to numerical simulations for D = 7 giving new estimations of the freezing point for this dimensionality.
Displasia espóndilo-epifisiaria asociada a cráneo-sinostosis, cataratas, paladar hendido y retardo mental: Reporte de un caso
Herrera-Martínez,Aura D; Estrada-Corona,Pedro;
Investigación Clínica , 2010,
Abstract: skeletal dysplasias are a heterogeneous group of disorders characterized by an alteration of the organization of osseous tissue causing a distortion on the growth and development pattern of bones. in 1998, four japanese sibs were described by the first time, three males and one female who presented a previously undescribed spondylo-epiphyseal dysplasia associated with craniosynostosis, cataracts, cleft palate and different grades of mental retardation. a probable autosomic recessive inheritance was suggested, but a germinal mosaicism could not be discarded. this is a case report of a patient with clinical and radiological findings similar to the ones previously described, born to second degree consanguineous parents. this supports the postulated presumption of a mutation with an autosomic recesive inheritance. the present comunication represents the fifth case reported in the literature and the second familiar group affected
Violencia y temor por la vida en mujeres jaliscienses violentadas por su pareja íntima
Estrada Pineda,Cristina; Rodríguez Díaz,Francisco Javier;
Revista Cubana de Salud Pública , 2011, DOI: 10.1590/S0864-34662011000400010
Abstract: introduction data on the attention paid to the needs of the victims of gender violence in their personal relationships with their partners do not take generally into account the variables affecting the service. these aspects have been defined in the general law of access to violence-free life where the first step would be to learn about rather than to ignore the realities. objectives to present the aspects of violence on the part of a sexual partner in the personal relationships of a couple and the request for help in a group of women living in the metropolitan area of guadalajara, jalisco, mexico. methods a cross-sectional quantitative study was conducted. the instrument was semi-structured interview made to 204 women who went to several institutions of the metropolitan area to state that they had been abused by their partners. results psychological violence prevailed in 98% of women whereas oral aggression was more frequent in 97.1%. a high percentage of battered women, regardless of the coercitive means used by the partner, feared for their lives. additionally, 67.7% of women neither asked for help nor reported the violent action. conclusions in the metropolitan area of guadalajara, there exists a significant number of women who feared for their personal relationships in their houses; they have lacked support and personal resources to get out of their abusive environment and to report these actions. this violence also brings about more health problems for the females, in terms of physical condition, integration and social adaptation.
Violencia y temor por la vida en mujeres jaliscienses violentadas por su pareja íntima Violence and fear for life seen in women from Jalisco who are abused by their partners
Cristina Estrada Pineda,Francisco Javier Rodríguez Díaz
Revista Cubana de Salud Pública , 2011,
Abstract: Introducción Los datos relativos a la atención de las necesidades de las víctimas de violencia de género en las relaciones interpersonales con su pareja íntima, en general no toman en cuenta las variables que inciden en el problema del servicio. Estos aspectos se encuentran definidos, a su vez, en la ley General de Acceso a una Vida Libre de Violencia, donde un primer paso sería conocer y no ignorar la realidad. Objetivos Presentar los aspectos relacionados con la violencia por parte de la pareja en las relaciones interpersonales y la petición de ayuda, en un grupo de mujeres que habita en la zona metropolitana de Guadalajara, Jalisco, México. Métodos La investigación es cuantitativa de corte transversal. El instrumento utilizado fue una entrevista semiestructurada a 204 mujeres que manifestaron que habían sido violentadas por su pareja íntima. Resultados La violencia de tipo psicológica en el 98 % de mujeres fue la predominante y la agresión verbal, en el 97,1 %, la más frecuente. Un alto porcentaje de las mujeres victimas de violencia física, independientemente del medio coercitivo utilizado, temieron por sus vidas. El 65,7 % de las mujeres no solicitó ayuda ni hizo denuncia. Conclusiones En la zona metropolitana de Guadalajara existe un grupo importante de mujeres atemorizadas en su convivencia interpersonal dentro de sus hogares, a las cuales les han faltado apoyo y recursos personales para salir del núcleo maltratante y denunciar. Los servicios asistenciales, policiales y de salud tienen que mejorar las prestaciones a esta población. Introduction Data on the attention paid to the needs of the victims of gender violence in their personal relationships with their partners do not take generally into account the variables affecting the service. These aspects have been defined in the General Law of Access to Violence-Free Life where the first step would be to learn about rather than to ignore the realities. Objectives To present the aspects of violence on the part of a sexual partner in the personal relationships of a couple and the request for help in a group of women living in the metropolitan area of Guadalajara, Jalisco, Mexico. Methods A cross-sectional quantitative study was conducted. The instrument was semi-structured interview made to 204 women who went to several institutions of the metropolitan area to state that they had been abused by their partners. Results Psychological violence prevailed in 98% of women whereas oral aggression was more frequent in 97.1%. A high percentage of battered women, regardless of the coercitive means used by the
Biodiversity of Myxomycetes from the Monte Desert of Argentina
Lado, C.,Wrigley de Basanta, D.,Estrada-Torres, A.
Anales del Jardín Botánico de Madrid , 2011,
Abstract: A biodiversity survey for myxomycetes was carried out in the Monte Desert (Argentina) and surrounding areas in November 2006 and late February and March 2007. Specimens were collected in seven different provinces (Catamarca, Jujuy, La Rioja, Salta, San Juan, San Luis and Tucumán), between 23o and 33o S latitude, and a total of 105 localities were sampled. Cacti and succulent plants were the most common type of substrate investigated, but shrubs and herbs characteristic of this biome were also included in the survey. Almost six hundred specimens of myxomycetes from 72 different species in 22 genera were collected either in the field, or from moist chamber cultures prepared with samples of plant material obtained from the same collecting sites. The results include 1 species new to science, Macbrideola andina three more species recently described based on material from this survey, 5 species cited for the first time for the Neotropics, 11 new records for South America and 38 new records for Argentina. Taxonomic comments on rare or unusual species are included and illustrated with photographs by LM and SEM. Data are presented on the development of some species and microenvironmental factors are discussed. An analysis of the biodiversity of myxomycetes in this area, and a comparison with other desert areas, are included. Con el objetivo de estudiar la biodiversidad de Myxomycetes en el Desierto de Monte (Argentina) y áreas circundantes, se realizó un muestreo en los meses de noviembre de 2006 y febrero y marzo de 2007. Se recolectaron especímenes en un total de 105 localidades pertenecientes a siete provincias (Catamarca, Jujuy, La Rioja, Salta, San Juan, San Luis y Tucumán), situadas entre los paralelos 23o y 33o de latitud sur. Los cactus y plantas suculentas fueron los tipos de sustratos más estudiados, pero también se analizaron arbustos y plantas herbáceas características de este bioma. Casi 600 especímenes de mixomicetes pertenecientes a 72 especies y 22 géneros fueron recolectados en el campo o se obtuvieron en el laboratorio, por cultivo en cámara húmeda, a partir de plantas procedentes de las mismas localidades. Los resultados incluyen una nueva especie, Macbrideola andina, otras tres recientemente descritas y basadas en material de este estudio, 5 especies que se citan por primera vez para el Neotrópico, 11 nuevos registros para América del Sur y 38 nuevos registros para Argentina. Se a aden comentarios taxonómicos e ilustraciones fotográficas, tanto con microscopía óptica como electró ni ca, de aquellas especies raras o poco comunes. Se discuten n
Assessment physical load of dockers in a worker cooperative
Hernán D. Zapata,Gloria L. Arango,Luz M. Estrada
Revista Facultad Nacional de Salud Pública , 2011,
Abstract: Manual labourers are workers whose job consists of humping goods. Task commonly related to a varied level of mechanical stress due both to its mechanical stress demand and the workplace risk factors. Objectives: to determine the level of exposure to physical workload amongst a sample of manual labourers who work at the factory of food concentrate for animal. To propose general administrative control and working atmosphere measures. Methodology: a study of descriptive observational type by convenience was carried out. The sample consisted of 41 manual labourers who were administered a socio-demographic survey in order to know the population characteristics. To those fulfilling the inclusion criteria, a heart rate monitoring was used. Afterwards, the Frimat method was administered to determine the levels of exposure to physical work load according to workload rates. Statistical analysis favoured was descriptive and non-parametric (Chisquare χ ) Results: two out of the four work sites under study constitute the most representative workload to personnel. While the study, the three labourers (100%) shoving and 14 (63.6%) out of the 22 labourers loading goods up and down ranged from hard to extremely tough levels of workload. Conversely, 11(91.7%) labourers carrying raw material and 4 (100%) sewing sacks were placed under a low level ranging between a minimal and bearable workload. Discussion: the kinds of job as well as the activities related to it affect the level of physical workload. Personal factors can have an influence upon physical workload.
Spondylo-epiphyseal dysplasia associated with craniosynostosis, cleft palate and mental retardation: A case report Displasia espóndilo-epifisiaria asociada a cráneo-sinostosis, cataratas, paladar hendido y retardo mental: Reporte de un caso
Aura D Herrera-Martínez,Pedro Estrada-Corona
Investigación Clínica , 2010,
Abstract: Skeletal dysplasias are a heterogeneous group of disorders characterized by an alteration of the organization of osseous tissue causing a distortion on the growth and development pattern of bones. In 1998, four Japanese sibs were described by the first time, three males and one female who presented a previously undescribed spondylo-epiphyseal dysplasia associated with craniosynostosis, cataracts, cleft palate and different grades of mental retardation. A probable autosomic recessive inheritance was suggested, but a germinal mosaicism could not be discarded. This is a case report of a patient with clinical and radiological findings similar to the ones previously described, born to second degree consanguineous parents. This supports the postulated presumption of a mutation with an autosomic recesive inheritance. The present comunication represents the fifth case reported in the literature and the second familiar group affected Las displasias esqueléticas son un grupo muy heterogéneo de trastornos que se caracterizan por una alteración en la organización del tejido óseo, lo que causa una distorsión en su patrón de crecimiento y desarrollo. En 1998, se descibió el caso de cuatro hermanos japoneses, tres varones y una hembra que presentaban una displasia espóndilo-epifisiaria, no descrita anteriormente, asociada con cráneo-sinostosis, cataratas, paladar hendido y retardo mental de diferente grado. Se planteó una probable herencia autosómica recesiva, debido a que las alteraciones afectaban a ambos sexos y los padres eran fenotípicamente sanos, aunque con discreto retardo mental; sin embargo, no fue posible descartar un mosaicismo germinal. El caso que se presenta, trata de un paciente con signos clínicos y radiológicos que coinciden con los previamente descritos. Es producto de padres consanguíneos en la segunda generación, lo cual se sumaría a la presunción ya postulada, de una probable mutación de herencia autosómica recesiva. La presente comunicación, representa el segundo reporte en la literatura, del quinto caso descrito y el segundo grupo familiar con la afección mencionada
Analysis of pollen-specific alternative splicing in Arabidopsis thaliana via semi-quantitative PCR
April D Estrada,Nowlan H Freese,Ann E Loraine
PeerJ , 2015, DOI: 10.7287/peerj.preprints.594v1
Abstract: Alternative splicing enables a single gene to produce multiple mRNA isoforms by varying splice site selection. In animals, alternative splicing of mRNA isoforms between cell types is widespread and supports cellular differentiation. In plants, at least 20% of multi-exon genes are alternatively spliced, but the extent and significance of tissue-specific splicing is less well understood, partly because the cell wall makes it difficult to isolate cells of a single type. Pollen is a useful model system to study tissue-specific splicing in higher plants because pollen grains contain only two cell types and can be collected in large amounts without damaging cells. Previously, we identified pollen-specific splicing patterns by comparing RNA-Seq data from Arabidopsis pollen and leaves. Here, we used semi-quantitative PCR to validate pollen-specific splicing patterns among genes where RNA-Seq data analysis indicated splicing was most different between pollen and leaves. PCR testing confirmed eight of nine alternative splicing patterns, and results from the ninth were inconclusive. In four genes, alternative transcriptional start sites coincided with alternative splicing. For most genes, RNA-Seq and PCR-based estimates of the different splice variants were similar, highlighting the value of the low-cost PCR assay as a method of validating RNA-Seq results.[b]
Surface Vacuum Energy in Cutoff Models: Pressure Anomaly and Distributional Gravitational Limit
Ricardo Estrada,Stephen A. Fulling,Fernando D. Mera
Mathematics , 2012, DOI: 10.1088/1751-8113/45/45/455402
Abstract: Vacuum-energy calculations with ideal reflecting boundaries are plagued by boundary divergences, which presumably correspond to real (but finite) physical effects occurring near the boundary. Our working hypothesis is that the stress tensor for idealized boundary conditions with some finite cutoff should be a reasonable ad hoc model for the true situation. The theory will have a sensible renormalized limit when the cutoff is taken away; this requires making sense of the Einstein equation with a distributional source. Calculations with the standard ultraviolet cutoff reveal an inconsistency between energy and pressure similar to the one that arises in noncovariant regularizations of cosmological vacuum energy. The problem disappears, however, if the cutoff is a spatial point separation in a "neutral" direction parallel to the boundary. Here we demonstrate these claims in detail, first for a single flat reflecting wall intersected by a test boundary, then more rigorously for a region of finite cross section surrounded by four reflecting walls. We also show how the moment-expansion theorem can be applied to the distributional limits of the source and the solution of the Einstein equation, resulting in a mathematically consistent differential equation where cutoff-dependent coefficients have been identified as renormalizations of properties of the boundary. A number of issues surrounding the interpretation of these results are aired.
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