884 research outputs found

    Influencia de la microestructura en las propiedades mecánicas de alta temperatura de los Eutécticos Al2O3/Y3Al5O12 crecidos por solidificación direccional

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    En este trabajo se ha realizado un estudio del sistema eutéctico Al2O3/Y3Al5O12 crecido a distintas velocidades mediante solidificación direccional de zona flotante por calentamiento con láser. El análisis microestructural se ha realizado mediante Microscopía Electrónica de Barrido (MEB) y de Transmisión (MET), tanto en muestras tras el procesado con láser como en muestras sometidas a los distintos tratamientos termo-mecánicos. El estudio de las propiedades mecánicas se ha llevado a cabo mediante ensayos a velocidad de deformación constante y ensayos de fluencia -a carga de compresión constante- para diversos valores de tensión y de temperatura en atmósfera de aire. De los resultados obtenidos se deduce que la resistencia está íntimamente asociada a la microestructura de las muestras, la cual depende de la velocidad de solidificación. La presencia de dislocaciones es clara a altas velocidades de deformación, observándose los mecanismos activos de deformación típicos de la alúmina monocristalinas, como son la formación de bucles de dislocaciones para evitar obstáculos. Los valores de los exponentes de tensión y la energía de activación sugieren un comportamiento difusional para bajas velocidades de deformación, a las que no se observan dislocaciones.The Al2O3/Y3Al5O12 eutectic system melt grown by laser heating float zone in a range of pull rates has been studied. The microstructural analysis has been made by Scaning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) in as-fabricated and tested samples. The mechanical properties have been studied by compression tests at constant crosshead speed and compression creep for a range of stresses and temperatures in air. It has been determined that the resistance is intimately associated to processing. The presence of dislocations is clear after plastic deformation at high strain rates, being active the typical deformation mechanisms of alumina single crystals, like dislocation loop formation to avoid obstacles. The values of the stress exponents and the activation energy suggest a diffusional control for plastic deformation at low strain rates, where dislocations are not observed

    A label free disposable device for rapid isolation of rare tumor cells from blood by ultrasounds

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    The use of blood samples as liquid biopsy is a label-free method for cancer diagnosis that offers benefits over traditional invasive biopsy techniques. Cell sorting by acoustic waves offers a means to separate rare cells from blood samples based on their physical properties in a label-free, contactless and biocompatible manner. Herein, we describe a flow-through separation approach that provides an efficient separation of tumor cells (TCs) from white blood cells (WBCs) in a microfluidic device, "THINUS-Chip" (Thin-Ultrasonic-Separator-Chip), actuated by ultrasounds. We introduce for the first time the concept of plate acoustic waves (PAW) applied to acoustophoresis as a new strategy. It lies in the geometrical chip design: different to other microseparators based on either bulk acoustic waves (BAW) or surface waves (SAW, SSAW and tSAW), it allows the use of polymeric materials without restrictions in the frequency of work. We demonstrate its ability to perform high-throughput isolation of TCs from WBCs, allowing a recovery rate of 84%±8% of TCs with a purity higher than 80% and combined viability of 85% at a flow rate of 80 µL/min (4.8 mL/h). The THINUS-Chip performs cell fractionation with low-cost manufacturing processes, opening the door to possible easy printing fabrication

    The role of violent video game exposure, personality, and deviant peers in aggressive behaviors among adolescents: a two-wave longitudinal study

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    The impact of violent video game exposure (VVGE) on aggressive behaviors has been extensively explored, but still remains controversial. Although some studies have shown slight detrimental short-term effects of VVGE, other studies have failed to find any consequence. In addition, the existence of long-lasting effects on aggressiveness, or their impact on adolescents, are still not well established. One limitation of most of these studies is that they do not control for other important risk variables for aggressive behaviors, such as personality and deviant peers, nor have they investigated the possible moderation role of these risk factors in the link between VVGE and aggression. Therefore, the main aim was to examine the additive and interactive role of VVGE, personality, and deviant peers in adolescent aggressive behaviors cross-sectionally and longitudinally. Many regression analyses and a cross-lagged autoregressive model were carried out. At both waves, aggressive behavior was predicted by having deviant peers and specific personality traits, especially low agreeableness. VVGE also presented a slight but significant effect at both waves, but it became nonsignificant when controlling for other variables. No long-term effects on the relation between VVGE and aggressive behaviors were found. Some moderation effects were consistently found at both waves: when participants reported having more deviant peers, the effects of VVGE and low agreeableness on aggressive behaviors significantly increased. These findings suggest that multiple biopsychosocial variables and their complex interplay need to be examined to gain a better understanding of the origin and expression of aggressive behavior

    No evidence that wild red deer (Cervus elaphus) on the Iberian Peninsula are a reservoir of Mycobacterium avium subspecies paratuberculosis infection

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    The potential role of red deer (Cervus elaphus) as a reservoir of Mycobacterium avium subspecies paratuberculosis (MAP) infection is largely unknown. A total of 332 wild red deer were investigated using post-mortem examination, bacteriology and serology. Only three animals (1.12%) were found to have lesions on histopathological examination and no MAP bacteria were recovered on culture. The results suggest it is unlikely that wild red deer make a significant contribution to the maintenance of MAP infection in the region. The cross-reactivity of the ELISAs used indicates this diagnostic modality is ineffective in the detection of MAP infection in this species. The implications of these results for the control of this important pathogen in both livestock and wildlife are discussed

    Gene therapy with mesenchymal stem cells expressing IFN-ß ameliorates neuroinflammation in experimental models of multiple sclerosis

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    [Background and Purpose]: Recombinant IFN‐ß is one of the first‐line treatments in multiple sclerosis (MS), despite its lack of efficacy in some patients. In this context, mesenchymal stem cells (MSCs) represent a promising therapeutic alternative due to their immunomodulatory properties and multipotency. Moreover, by taking advantage of their pathotropism, these cells can be genetically modified to be used as carriers for delivering or secreting therapeutic drugs into injured tissues. Here, we report the therapeutic effect of systemic delivery of adipose‐derived MSCs (AdMSCs), transduced with the IFN‐β gene, into mice with experimental autoimmune encephalomyelitis (EAE).[Experimental Approach]: Relapsing–remitting and chronic progressive EAE were induced in mice. Cells were injected i.v. Disease severity, inflammation and tissue damage were assessed clinically, by flow cytometry of spleens and histopathological evaluation of the CNS respectively.[Key Results]: Genetic engineering did not modify the biological characteristics of these AdMSCs (morphology, growth rate, immunophenotype and multipotency). Furthermore, the transduction of IFN‐ß to AdMSCs maintained and, in some cases, enhanced the functional properties of AdMSCs by ameliorating the symptoms of MS in EAE models and by decreasing indications of peripheral and central neuro‐inflammation.[Conclusion and Implications]: Gene therapy was found to be more effective than cell therapy in ameliorating several clinical parameters in both EAE models, presumably due to the continuous expression of IFN‐β. Furthermore, it has significant advantages over AdMSC therapy, and also over systemic IFN‐ß treatment, by providing long‐term expression of the cytokine at therapeutic concentrations and reducing the frequency of injections, while minimizing dose‐limiting side effects.This work was supported by Fondo de Investigaciones Sanitarias ISCIII (Spain) and Fondo Europeo de Desarrollo Regional (FEDER) from the European Union through the research grants PI12/01097 and PI15/00963 and ISCIII Red de Terapia Celular TerCel RD12/0019/0006 to F.M., by the Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía‐FEDER/Fondo de Cohesion Europeo (FSE) de Andalucía through the research grants P09‐CTS‐04532, PI‐57069 and PAIDI‐Bio‐326 to F.M. and PI‐0160/2012 to K.B. M.J.P.‐M. has been supported by grants from Red Temática de Investigación Cooperativa Red Española de Esclerosis Múltiple REEM (RD07/0060 and RD12/0032). B.O. is financed by a contract from Excelent Project CTS‐7670/11 from Consejería de Economía, Innovación, Ciencia y Empleo (Junta de Andalucía)

    La Cuevona de Avín (Avín, Asturias, North Spain): A new Late Pleistocene site in the lower valley of the River Güeña

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    The archaeological investigations carried out in the last twenty years in the Lower Valley of the River Güeña (Asturias, central part of northern Spain) have documented different prehistoric sites, particularly with Middle and Upper Palaeolithic occupations. This paper presents the first results of the archaeological excavation carried out in the cave of La Cuevona de Avín. From the systematic study of the biotic and abiotic remains, a total of three occupation phases (Phases 1 to 3) have been determined, dated in the Late Pleistocene. The lithic studies indicate the use of local raw materials (mainly quartzite), but also regional ones (different types of flint) in the whole sequence. Retouched implements are typologically representative only during the Upper Magdalenian (Phase II) and use-wear analysis indicates the manufacture and use of artefacts in situ during this phase. Archaeozoological studies reveal continuity in subsistence strategies throughout the sequence, noting specialization in red deer hunting during the Azilian (Phase I), and more diversified prey in the older phases of the sequence. © 2022 The Author(s

    Memoria de trabajo en niños de educación infantil con y sin bajo rendimiento matemático

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    This study aims to explore working memory in preschool children with and without low mathematical performance. The sample consisted of 255 children aged 5-6 years, to whom were administered neuropsychological tests of working memory and TEDI-MATH to estimate the mathematical performance. The results highlight the capacity of verbal working memory to significantly differentiate groups of children with and without problems in 8 of the 9 analyzed mathematical domains. This factor together with visuospatial working memory differentiate the group of children at risk for mathematical learning disabilities.Este estudio se propone analizar la memoria de trabajo en niños de Educación Infantil con y sin bajo rendimiento matemático. La muestra estaba compuesta de 255 niños de 5 a 6 años, a los que se les aplicó pruebas neuropsicológicas de memoria de trabajo y el TEDI-MATH para estimar el rendimiento matemático. Los resultados destacan la capacidad de la memoria de trabajo verbal para diferenciar significativamente los grupos de niños con y sin dificultades en 8 de los 9 dominios matemáticos analizados. Este mismo factor junto con la memoria de trabajo viso-espacial estática diferencian al grupo de niños con riesgo de aprendizaje de las matemáticas

    Access to Enantiopure 5‑, 7‑, and 5,7-Substituted cis- Decahydroquinolines: Enantioselective Synthesis of (−)-Cermizine B

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    Stereoconvergent cyclocondensation reactions of (R)- or (S)-phenylglycinol with appropriately substituted cyclohexanone-based δ-keto esters are the key steps of short synthetic routes to enantiopure 5-, 7-, and 5,7-substituted cisdecahydroquinolines. The factors governing the stereoselectivity of the cyclocondensation are discussed. The potential of the methodology is illustrated by a protecting-group-free synthesis of the phlegmarine-type Lycopodium alkaloid (-)-cermizine B

    A Multicentre, Randomised, Controlled Trial of a Combined Clinical Treatment for First-Episode Psychosis

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    Nurses working at nursing homes are one of the most vulnerable populations for suffering burnout and compassion fatigue. In Spain, the concept of compassion fatigue and psychological flexibility related to stress in geriatric nurses has not been fully explored until now. It is important to analyze their situation in order to design robust coping and management strategies. The aim was to analyze the relationship between burnout, compassion fatigue and psychological flexibility in geriatric nurses in Spain. Participants included 291 nurses from 97 centers in 51 cities across Spain. Psychological flexibility (AAQ-II), burnout (MBI) and compassion fatigue (ProQOL) were evaluated. Responses were recievced from 281 nurses (91% women), with an average of 7.6 years of work experience. The MBI results were average (26.71), and the ProQOL scores were average for compassion fatigue (40.2%) and high for compassion satisfaction (70.3%), whereas for AAQ-II, the mean score was 37.34 (SD 4.21). The correlation was significant and negative for flexibility, burnout and compassion fatigue, and positive for compassion satisfaction. The ANOVA indicated a significant association between all variables (p < 0.05). We can conclude that geriatric nurses suffer from medium levels of burnout and compassion fatigue, together with high levels of psychological flexibility, which appears to act as a stress reliever, supporting compassion satisfaction

    Predictive factors and early biomarkers of response in multiple sclerosis patients treated with natalizumab

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    There are an increasing number of treatments available for multiple sclerosis (MS). The early identification of optimal responders to individual treatments is important to achieve individualized therapy. With this aim, we performed a multicenter retrospective longitudinal study including 186 MS patients treated with natalizumab who were followed for 2 years. We analyzed the following variables at recruitment: sex, current age, age at disease onset, disease duration, EDSS, number of T2 and Gd + lesions, IgG and IgM oligoclonal bands, HLA class II (DR, DRB, DQA, DQB, and DRB1*15:01), IgG and IgM antibody titers against human herpesvirus 6 (HHV-6) and the antibody response to Epstein–Barr virus (EBV) through the measurement of the anti-EBNA-1 and anti-VCA IgG titers, in relation to clinical response (no relapses or disability progression), and to NEDA-3 (no evidence of disease activity in terms of clinical response and no changes in MRI scans either) after 2-years follow-up. Baseline EDSS score, baseline EBNA-1 IgG titers and percentage change of HHV6 IgG titers between baseline and 6 month visits were significantly different in clinical responders and in NEDA-3 status (all of them remained significant in the multivariate analysis). We identified three variables for the early identification of natalizumab optimal responders in a rapid and cost-effective approach
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