High-temperature mechanical behavior of polycrystalline yttrium-doped barium cerate perovskite

The high-temperature mechanical properties of the mixed ionic-electronic conductor perovskite BaCe0.95Y0.05O3-δ with average grain size of 0.40μm have been studied in compression between 1100 and 1300°C in air at different initial strain rates. The true stress-true strain curves display an initial stress drop, followed by an extended steady-state stage. As the temperature decreases and/or the strain rate increases, there is a transition to a damage-tolerant strain-softening stage and eventually to catastrophic failure. Analysis of mechanical and microstructural data revealed that grain boundary sliding is the primary deformation mechanism. The strength drop has been correlated with the growth of ultrafine grains during deformation, already present at grain boundaries and triple grain junctions in the as-fabricated material.Ministerio de Ciencia e Innovación MAT2009-13979-C03-0

Mechanical resistance of zirconium implant abutments : a review of the literature

The increase of aesthetic demands, together with the successful outcome of current implants, has renewed interest in the search for new materials with enough mechanical properties and better aesthetic qualities than the materials customarily used in implanto-prosthetic rehabilitation. Among these materials, zirconium has been used in different types of implants, including prosthetic abutments. The aim of the present review is to analyse current scientific evidence supporting the use of this material for the above mentioned purposes. We carried out the review of the literature published in the last ten years (2000 through 2010) of in vitro trials of dynamic and static loading of zirconium abutments found in the databases of Medline and Cochrane using the key words zirconium abutment, fracture resistance, fracture strength, cyclic loading. Although we have found a wide variability of values among the different studies, abutments show favourable clinical behaviour for the rehabilitation of single implants in the anterior area. Such variability may be explained by the difficulty to simulate daily mastication under in vitro conditions. The clinical evidence, as found in our study, does not recommend the use of implanto-prosthetic zirconium abutments in the molar area. © Medicina Oral S. L

Mechanical behavior of single-layer ceramized zirconia abutments for dental implant prosthetic rehabilitation

Objectives: This study was undertaken to characterize the mechanical response of bare (as-received) and single- layer ceramized zirconia abutments with both internal and external connections that have been developed to enhan - ced aesthetic restorations. Material and Methods: Sixteen zirconia implant abutments (ZiReal Post®, Biomet 3i, USA) with internal and ex - ternal connections have been analyzed. Half of the specimens were coated with a 0.5mm-thick layer of a low-fusing fluroapatite ceramic. Mechanical tests were carried out under static (constant cross-head speed of 1mm/min until fracture) and dynamic (between 100 and 400N at a frequency of 1Hz) loading conditions. The failure location was identified by electron microscopy. The removal torque of the retaining screws after testing was also evaluated. Results: The average fracture strength was above 300N for all the abutments, regardless of connection geometry and coating. In most of the cases (94%), failure occurred by abutment fracture. No significant differences were observed either in fatigue behavior and removal torque between the different abutment groups. Conclusions: Mechanical behavior of Zireal zirconia abutments is independent of the type of internal/external connection and the presence/absence of ceramic coating. This may be clinically valuable in dental rehabilitation to improve the aesthetic outcome of zirconia-based dental implant systems

High incidence of clinical fragility fractures in postmenopausal women with rheumatoid arthritis. A case-control study.

Objectives: To estimate the incidence of clinical fragility fractures in postmenopausal women with rheumatoid arthritis (RA) and analyze risk factors for fracture. Methods: Incidence of clinical fragility fractures in 330 postmenopausal women with RA was compared to that of a control population of 660 age-matched postmenopausal Spanish women. Clinical fractures during the previous five years were recorded. We analyzed associations with risk factors for fracture in both populations and with disease-related variables in RA patients. Results: Median age of RA patients was 64 years; median RA duration was eight years. Sixty-nine percent were in remission or on low activity. Eighty-five percent had received glucocorticoids (GCs); 85 %, methotrexate; and 40 %, ≥1 biologic DMARD. Fifty-four patients and 47 controls had ≥1 major osteoporotic fracture (MOF). Incidence of MOFs was 3.55 per 100 patient-year in patients and 0.72 in controls (HR: 2.6). Risk factors for MOFs in RA patients were age, previous fracture, parental hip fracture, years since menopause, BMD, erosions, disease activity and disability, and cumulative dose of GCs. Previous fracture in RA patients was a strong risk for MOFs (HR: 10.37). Conclusion: Of every 100 postmenopausal Spanish women with RA, 3-4 have a MOF per year. This is more than double that of the general population. A previous fracture poses a high risk for a new fracture. Other classic risk factors for fracture, RA disease activity and disability, and the cumulative dose of GCs are associated with fracture development

Predictive Power of the "Trigger Tool" for the detection of adverse events in general surgery: a multicenter observational validation study

Background In spite of the global implementation of standardized surgical safety checklists and evidence-based practices, general surgery remains associated with a high residual risk of preventable perioperative complications and adverse events. This study was designed to validate the hypothesis that a new “Trigger Tool” represents a sensitive predictor of adverse events in general surgery. Methods An observational multicenter validation study was performed among 31 hospitals in Spain. The previously described “Trigger Tool” based on 40 specific triggers was applied to validate the predictive power of predicting adverse events in the perioperative care of surgical patients. A prediction model was used by means of a binary logistic regression analysis. Results The prevalence of adverse events among a total of 1,132 surgical cases included in this study was 31.53%. The “Trigger Tool” had a sensitivity and specificity of 86.27% and 79.55% respectively for predicting these adverse events. A total of 12 selected triggers of overall 40 triggers were identified for optimizing the predictive power of the “Trigger Tool”. Conclusions The “Trigger Tool” has a high predictive capacity for predicting adverse events in surgical procedures. We recommend a revision of the original 40 triggers to 12 selected triggers to optimize the predictive power of this tool, which will have to be validated in future studies

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Fabricación y comportamiento mecánico a alta temperatura de BaCe(Y, Yb)O3

En este trabajo se estudia la fabricación y la caracterización estructural, microestructural y mecánica de compuestos de BaCeO3 dopado con itrio e iterbio (contenidos de 0-20 at%). Estos compuestos son de tipo perovskita (ABO3), donde el dopado con cationes trivalentes sustituyen a los cationes B4+ introduciendo simultáneamente vacantes de oxígeno por compensación de carga. En presencia de atmósferas con vapor de agua o hidrógeno, estas vacantes crean defectos protónicos, que presentan una alta movilidad a temperaturas intermedias y altas. Por tanto, esta clase de materiales tienen un gran potencial como electrolitos en las pilas de combustible de óxido sólido (Solid Oxide Fuel Cells, SOFC) operando a temperaturas T 500 C, cuya tecnología se presenta como una alternativa válida dentro de las nuevas fuentes de energías limpias y eficaces.

Caracterización mecánica de pilares de circonio sometidos a ceramización

Los dos objetivos fundamentales de la implantología moderna son la función y estética; objetivos que pueden alcanzarse gracias a los materiales cerámicos, ideales para reemplazar estructuras dentarias gracias a sus cualidades ópticas y su estabilidad intraoral a largo plazo. La circona presenta propiedades mecánicas muy parecidas a la de los metales y su color es muy similar al de los dientes. La circona estabilizada con óxido de itrio presenta las mejores propiedades para estas aplicaciones. La primera vez que se utilizó la circona con fines médicos fue en 1969: Helmer y Driskell lo presentaron como material para aplicaciones ortopédicas en el Symposium on Use of Ceramics as Surgical Implants; se propuso para el reemplazo de la cabeza del fémur en lugar del titanio o las prótesis de alumina . Wohlwend et al. presentaron el primer pilar de circona, Zirabut® (Wohlwena Innovative, Zurich, Switzerland) en 1997. Sadoun y Perelmuter describieron la confección de un pilar alumina-circona en laboratorio dental Implant Innovation, Inc. (Palm Beach Garden, Florida), diseñaron y presentaron un pilar de circona (ZiReal® Post), la característica de este pilar es que consiste en un componente de titanio fusionado a la circona en su porción apical. Este diseño permite el contacto metal-metal entre la interfase pilar-implante lo cual debe ser una asociación altamente predecible (4). El desarrollo y generalización de los sistemas protésicos cerámicos requiere un conocimiento más amplio de su comportamiento mecánico, para su uso no sólo en restauraciones unitarias del sector anterior, sino también en los sectores posteriores. Por este motivo hemos iniciado un estudio preliminar sobre nuevos sistemas protésicos con pilar de circona, fabricados por la empresa Biomet 3i (Palm Beach Garden, Florida), con el objetivo de caracterizar la resistencia a la fractura y el comportamiento en fatiga dinámica de los pilares en condiciones que simulen los procesos de masticación cotidiana. Por tanto, el objetivo de este estudio preclínico fue determinar el comportamiento mecánico de dicho pilar y su resistencia a la fractura en ciclado bajo carga, simulando condiciones adversas de masticación, y si estas variables se veían afectadas por el proceso de ceramización del pilar

Diet quality index as a predictor of treatment efficacy in overweight and obese adolescents: The EVASYON study

The EVASYON Study Group.[Background & aim]: A diet quality index (DQI) is a tool that provides an overall score of an individual's dietary intake when assessing compliance with food-based dietary guidelines. A number of DQIs have emerged, albeit their associations with health-related outcomes are debated. The aim of the present study was to assess whether adherence to dietary intervention, and the overall quality of the diet, can predict body composition changes.[Methods]: To this purpose, overweight/obese adolescents (n = 117, aged: 13–16 years; 51 males, 66 females) were recruited into a multi-component (diet, physical activity and psychological support) family-based group treatment programme. We measured the adolescents' compliance and body composition at baseline and after 2 months (intensive phase) and 13 months (extensive phase) of follow-up. Also, at baseline, after 6 months, and at the end of follow-up we calculated the DQI.[Results]: Global compliance with the dietary intervention was 37.4% during the intensive phase, and 14.3% during the extensive phase. Physical activity compliance was 94.1% at 2-months and 34.7% at 13months and psychological support compliance were growing over the intervention period (10.3% intensive phase and 45.3% during extensive phase). Adolescents complying with the meal frequency criteria at the end of the extensive phase had greater reductions in FMI z-scores than those did not complying (Cohen's d = 0.53). A statistically significant association was observed with the diet quality index. DQI-A variation explained 98.1% of BMI z-score changes and 95.1% of FMI changes.[Conclusions]: We conclude that assessment of changes in diet quality could be a useful tool in predicting body composition changes in obese adolescents involved in a diet and physical activity intervention programme backed-up by psychological and family support.The study was supported by the Ministry of Health, Social Services and Equality via the Carlos III Institute of Health (FIS Grant PI051080, PI051579). The EVASYON study received the award for the best applied research project in 2009 from AESAN (Spanish Agency for Food Safety and Nutrition from the Spanish Ministry of Health and Consumer Affairs. The study was supported by Aragon's Regional Government (DGA, Diputación General de Aragón) and European Regional Development Fund.Peer reviewe

Bajo el signo de la luz : la fundación de una utopía andaluza

Esta publicación obtuvo el Primer Premio Joaquín Guichot a investigaciones, experiencias y materiales sobre Andalucía y su cultura en la edición XXVI del curso 2013/2014Se trata de un proyecto intercentros en el que se pretende convertir en aula a la comunidad. Nace para dar respuesta a las inquietudes de un alumnado y una población que ignoran, en buena medida, sus orígenes y los de sus antepasados. Como respuesta a esa necesidad, se vuelve sobre las huellas del tiempo para descubrir la epopeya de las nuevas poblaciones de Sierra Morena y Andalucía; una iniciativa que respondió a los ideales del Siglo de las Luces y a la necesidad de poblar los extensos terrenos que bordeaban el Camino Real. Con el formato de aprendizaje-servicio a la comunidad, el alumnado descubrirá que sus raíces culturales, sus apellidos y tradiciones, lejos de los localismos, provienen de Europa Central y suponen un ejemplo de integración cultural. "Bajo el signo de la luz" va más allá y sueña con llevar la utopía a la educación e intenta convertirse en un paradigma de integración del trabajo de Educación Infantil, Primaria y Secundaria, o de cualesquiera otras enseñanzas, y se apoya en el deseo idealista de dar a conocer la cultura andaluza al alumnado de nuestra Comunidad Autónoma.AndalucíaES