131 research outputs found

    Dynamics of excitable cells: spike-adding phenomena in action

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    We study the dynamics of action potentials of some electrically excitable cells: neurons and cardiac muscle cells. Bursting, following a fast–slow dynamics, is the most characteristic behavior of these dynamical systems, and the number of spikes may change due to spike-adding phenomenon. Using analytical and numerical methods we give, by focusing on the paradigmatic 3D Hindmarsh–Rose neuron model, a review of recent results on the global organization of the parameter space of neuron models with bursting regions occurring between saddle-node and homoclinic bifurcations (fold/hom bursting). We provide a generic overview of the different bursting regimes that appear in the parametric phase space of the model and the bifurcations among them. These techniques are applied in two realistic frameworks: insect movement gait changes and the appearance of Early Afterdepolarizations in cardiac dynamics

    Social Networks, Emotions, and Education: Design and Validation of e-COM, a Scale of Socio-Emotional Interaction Competencies among Adolescents

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    Socio-emotional competencies play an essential role in personal development as they are associated with highly prosocial behavior and low aggressiveness. An individual who is online manages his/her emotions in a specific manner. Thus, it is highly relevant to analyze and evaluate online socio-emotional competencies. Until now, however, no instruments had been defined or developed for that purpose. This study’s objective was thus to design and validate a questionnaire for the evaluation of socio-emotional competencies in virtual contexts, and to analyze eventual differences according to gender and academic year. Using the model developed by Bisquerra and Pérez (2007) as a theoretical framework, the competencies posited therein were transferred to an online environment. The questionnaire was filled out by 888 adolescents ages 12 to 17 (48% males, M = 13.83 years old, DT = 1.27), all residents of Aragón, Spain. On the basis of their responses, structure analysis, validation, and reliability were carried out. Confirmatory factor analysis (CFA) yielded a five-dimensional structure with good fit and internal consistency. The five resulting dimensions evaluate (1) emotional e-conscience, (2) emotional e-autonomy, (3) emotional e-regulation, (4) e-self-control of impulsiveness, and (5) social e-competency. Differences among genders were observed in the categories of emotional e-conscience and social e-competency. Furthermore, the results of this study show that online emotional expression does not imply emotional competency. These results represent an advance in the field of emotional education. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Optimization of laser-patterned YSZ-LSM composite cathode-electrolyte interfaces for solid oxide fuel cells

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    Patterned cathode/electrolyte interfaces formed by a hexagonal array of ~22 µm deep wells with 24 µm lattice parameter have been prepared by pulsed laser machining to enlarge the contact surface and, consequently, to reduce the cathode polarization of Solid Oxide Fuel Cells. These new interfaces have been tested in YSZ-LSM/YSZ/YSZ-LSM symmetrical cells, where the cathode is deposited by dip-coating. Appropriate ceramic suspensions have been formulated to penetrate into deep wells without presenting interfacial delamination after sintering. We analyse their applicability by comparing their rheology with the microstructure and electrochemical performance of the cells. The activation component of the polarization resistance is reduced by ~50% using ethanol-based suspensions with 20 wt% solids loading, although the gas diffusion component increases due to excessive densification. Alternative ceramic suspensions with 17.5 wt% solids loading provide optimum electrode gas diffusion but lower activation components, resulting in an overall decrease of ~20% in polarization resistance

    Fabrication and microstructure of self-supporting thin ceramic electrolytes prepared by laser machining

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    Self-supporting thin Yttria Stabilized Zirconia (YSZ) ceramics electrolytes have been prepared by laser machining. They are carved from a sintered YSZ plate to shape a 20 µm thick and 8 mm in diameter central region, surrounded by an unprocessed 150 µm thick supporting zone. Scanning Electron Microscopy (SEM) and Electron BackScattering Diffraction (EBSD) studies confirmed that the strains produced by the laser processing are small and limited to only one or two layers of YSZ grains (~5 µm). SEM and Transmission Electron Microscopy (TEM) have been also used to characterize the surface of the membrane. It is corrugated and coated with YSZ nanoparticles as a result of the laser plasma deposition. Electrochemical characterization by Impedance Spectroscopy (EIS) showed that this surface morphology improves the electrical performance of the membrane slightly but clearly, reducing the cathode polarization resistance by about 5% in the 650-850 ºC range.This study was funded by the MAT2012-30763 project, which is financed by the Spanish Government (Ministerio de Economía y Competitividad) and the Feder program of the European Union.Peer Reviewe

    Abuso de Internet y adolescentes: gratificaciones, supervisión familiar y uso responsable. Implicaciones educativas y familiares

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    Internet tiene un gran potencial educativo y social pero no por ello está exento de riesgos como la tecnoadicción o abuso de la tecnología. El objetivo de este trabajo es analizar en qué medida las gratificaciones, la supervisión familiar y su uso responsable influyen en el abuso de Internet y con ello comprender mejor este riesgo en la adolescencia de cara a que docentes y familias puedan establecer estrategias para su prevención. En el estudio participaron 555 adolescentes (55.7% chicos y 44.3 % chicas) de 1º-4º ESO (M: 13. 97 años y SD: 1. 27). Los datos se obtuvieron través de cuestionarios. Los resultados muestran que la evasión es la principal motivación para el abuso digital junto al entretenimiento y el logro digital. El uso responsable y la supervisión familiar juegan un papel protector. Se discuten las diferencias según el género y la edad y las implicaciones educativas para docentes y familias. Internet abuse has become a social problem in adolescence. Previous research suggested that it is related to the gratifications they receive from using it. However, it is unknown whether continued responsible use (netiquette) and family supervision can balance the rewards that promote this risk. Thus, the purpose of this paper is to analyze the extent to which gratifications, family supervision and responsible use predict Internet abuse and thereby better understand this risk in adolescence so that teachers and families can establish strategies for its prevention according to the gender and age. 555 adolescents (55.7% boys) from 1st to 4th year of ESO (M: 13. 97 years old and SD: 1.27) participated in the study. The data were obtained through questionnaires. The results reveal that, although mainly entertainment in boys and avoidance in girls promote abuse, educating netiquette is an important protection factor for both genders and all ages, as well as family supervision in girls and boys. in adolescents 12-13 years old. Educational and family implications are discussed

    Gene expression profiling and its use in adenocarcinomas of unknown primary origin: A case report

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    Carcinomas of unknown primary origin account for 3-5% of all malignancies. The current literature suggests that metastatic dissemination is able to occur in the absence of primary tumor growth. In metastatic disease that is difficult to diagnose, the origin usually remains unknown even after an exhaustive evaluation of immunohistochemistry (IHC) markers. In the current study, a 49-year-old male presented with lymph nodes metastases of unknown origin. The exci- sional biopsy of an inguinal node revealed an adenocarcinoma growth pattern, but the IHC could not determine the primary origin. A gene profiling test was performed to complete the diagnosis and a salivary gland adenocarcinoma was diagnosed with 90% probability. Subsequently, the patient underwent appropriate chemotherapy for salivary gland adenocarcinoma, and exhibited an improved partial response. The present case study highlights the importance of an accurate diagnosis of the primary tumor and the use of all the current tools available in order to provide patients with the best treatment possibl

    How does stent expansion alter drug transport properties of the arterial wall?

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    Stents have become the most successful device to treat advanced atherosclerotic lesions. However, one of the main issues with these interventions is the development of restenosis. The coating of stents with antiproliferative substances to reduce this effect is now standard, although such drugs can also delay re-endothelialization of the intima. The drug release strategy is therefore a key determinant of drug-eluting stent efficacy. Many mathematical models describing drug transport in arteries have been developed and, usually separately, models describing the mechanics of arterial tissue have been devised. However, the literature is lacking a comprehensive model that adequately takes into account both the mechanical deformation of the porous arterial wall and the resulting impact on drug transport properties. In this paper, we provide the most comprehensive study to date of the effect of stent mechanical expansion on the drug transport properties of a three-layer arterial wall. Our model incorporates the state-of-the art description of the mechanical properties of arterial tissue though an anisotropic, hyperelastic material model and includes a nonlinear saturable binding model to describe drug transport in the arterial wall. We establish relationships between mechanical force generated through device expansion and alteration in diffusion within the arterial wall and perform simulations to elucidate the impact of such alterations in spatio-temporal drug release and tissue uptake. Mechanical deformation of the arterial wall results in modified drug transport properties and tissue drug concentrations, highlighting the importance of coupling solid mechanics with drug transport

    Estudio para la mejora de la calidad del vino albariño

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    Premio de Investigación, Real Academia Galega de Ciencias, convocatoria 2009.[EN]Twenty-two clones from Albariño variety (Vitis vinifera L.), from an initial collection of 115 clones, were selected on the basis of their ampelographic, molecular and sanitary characteristics. These selected clones were studied from the agronomic and oenological point of view, and were also quantified for their levels of susceptibility to Powdery Mildew, Oidium and Botrytis. An ecotypic yeast was selected, its use has been patented and it is being exploited. Musts obtained from the previously selected Albariño clones were fermented with this yeast, essentially by increasing the content in volatile substances of interest (terpens: linalool and geraniol; norisoprenoids: α-ionone and β- damascenone), leading to wines with improved fermentative dynamic and sensorial attributes.[ES]En base a características ampelográficas, moleculares y sanitarias, se seleccionaron 22 clones de la variedad Albariño (Vitis vinifera L.), partiendo de 115 iniciales. Sobre los clones seleccionados se ha llevado a cabo un estudio agronómico y enológico, así como la cuantificación de los niveles de susceptibilidad a Mildiu, Oídio y Botrytis. Se ha seleccionado una levadura ecotípica, cuyo uso ha sido patentado y se encuentra en explotación. Con ella se fermentaron los mostos obtenidos a partir de los clones de Albariño previamente seleccionados, dando lugar a vinos con una dinámica fermentativa xPremio de Investigación, Real Academia Galega de Ciencias, convocatoria 2009 y unos atributos sensoriales mejorados, fundamentalmente en base al aumento del contenido en sustancias volátiles de interés (terpenos: linalool y geraniol; norisoprenoides: α-ionona y β- damascenona).La actividad realizada ha sido financiada, además de por la Bodega Terras Gauda S.A., por la Xunta de Galicia (PGIDIT04TAL035E), y por el propio CSIC (PIE 2004 7 0E 214).Peer reviewe

    Breast cancer PAM50 signature: correlation and concordance between RNA-Seq and digital multiplexed gene expression technologies in a triple negative breast cancer series

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    [Background]: Full RNA-Seq is a fundamental research tool for whole transcriptome analysis. However, it is too costly and time consuming to be used in routine clinical practice. We evaluated the transcript quantification agreement between RNA-Seq and a digital multiplexed gene expression platform, and the subtype call after running the PAM50 assay in a series of breast cancer patients classified as triple negative by IHC/FISH. The goal of this study is to analyze the concordance between both expression platforms overall, and for calling PAM50 triple negative breast cancer intrinsic subtypes in particular.[Results]: The analyses were performed in paraffin-embedded tissues from 96 patients recruited in a multicenter, prospective, non-randomized neoadjuvant triple negative breast cancer trial (NCT01560663). Pre-treatment core biopsies were obtained following clinical practice guidelines and conserved as FFPE for further RNA extraction. PAM50 was performed on both digital multiplexed gene expression and RNA-Seq platforms. Subtype assignment was based on the nearest centroid classification following this procedure for both platforms and it was concordant on 96% of the cases (N = 96). In four cases, digital multiplexed gene expression analysis and RNA-Seq were discordant. The Spearman correlation to each of the centroids and the risk of recurrence were above 0.89 in both platforms while the agreement on Proliferation Score reached up to 0.97. In addition, 82% of the individual PAM50 genes showed a correlation coefficient > 0.80.[Conclusions]: In our analysis, the subtype calling in most of the samples was concordant in both platforms and the potential discordances had reduced clinical implications in terms of prognosis. If speed and cost are the main driving forces then the preferred technique is the digital multiplexed platform, while if whole genome patterns and subtype are the driving forces, then RNA-Seq is the preferred method.M.M was supported by two research grants from Ministry of Economy and Competitiveness ISCIII-FIS grants (PI 12/02684): “Predictores genómicos de respuesta a la quimioterapia neoadyuvante con docetaxel-carboplatino en pacientes con cáncer de mama triple negativo”/“Genomic predictors of response to neoadjuvant chemotherapy with docetaxel-carboplatin in patients with triple negative breast cancer”; and (PI 15/00117): “Cáncer de mama triple negative: Predicción de respuesta a docetaxel-carboplatino neoadyuvante mediante caracterización de TILs y firmas inmunes basadas en secuenciación masiva de RNA”/” Triple negative breast cancer: Prediction of response to neoadjuvant docetaxel-carboplatin by characterization of TILs and immune signatures based on massive RNA sequencing”. C.M.P was supported by funds from the NCI Breast SPORE program (P50-CA58223).Peer reviewe
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