39 research outputs found

    Centrifugal Atomization of Glass-Forming Alloy Al86Ni8Y4.5La1.5

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    Centrifugal atomization is a rapid solidification technique for producing metal powders. However, its wide application has been limited to the production of common metal powders and their corresponding alloys. Therefore, there is a lack of research on the production of novel materials such as metallic glasses using this technology. In this paper, aluminum-based glassy powders (Al86Ni8Y4.5La1.5) were produced by centrifugal atomization. The effects of disk speed, atomization gas, and particle size on the cooling rate and the final microstructure of the resulting powder were investigated. The powders were characterized using SEM and XRD, and the amorphous fractions of the atomized powder samples were quantified through DSC analysis. A theoretical model was developed to evaluate the thermal evolution of the atomized droplets and to calculate their cooling rate. The average cooling rate experienced by the centrifugally atomized powder was calculated to be approximately 7 × 105 Ks−1 for particle sizes of 32.5 μm atomized at 40,000 rpm in a helium atmosphere. Amorphous fractions from 60% to 70% were obtained in particles with sizes of up to 125 μm in the most favorable atomization conditions

    Simulación de un tratamiento térmico mediante elementos finitos

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    En la industria abundan procesos térmicos o termo-mecánicos durante los cuales se producen distorsiones difíciles de predecir y controlar. Las diferentes velocidades de enfriamiento ocasionadas a lo la rgo de la pieza durante el proceso producen una distribución de fases con volumen específico y propiedades mecánicas diferentes, que generan tensiones internas y dichas distorsiones. Incorporar la evolución microest ructura l a la simulación permitiría definir procesos industriales optimizados. El objetivo principal de este trabajo ha sido incorporar a la simulación las transformaciones de fase y las distorsiones que estas producen . Como aplicación concreta se ha simulado el tratamiento térmico de un componente real . Se ha implementado el modelo de JMAK para determinar la evolución de las transformaciones de fase gobernadas por la difusión y el modelo de Koistinen-Marburger para la transformación martensítica. Para obtener el tiempo de incubación de las transformaciones no isotérm icas y el crecimiento de las propias fases se ha utilizado la Regla de Adición. Los coeficientes de expansión térmica de cada una de las fases han sido obtenidos de la bibliografía. Estos modelos se han incorporado mediante subrutinas de usuario. Los resultados obtenidos hacen concluir que los modelos no siempre describen fielmente las transformaciones de fase . La ferrita y la perlita quedan bastante bien modelizadas, sin embargo, para la bainita, tanto el tiempo de incubación como la fracción transformada no quedan bien descritos.Postprint (published version

    Promoció de l’envelliment actiu: Contribucions de la Vocalia de Psicologia de l’Envelliment del Col·legi Oficial de Psicologia de les Illes Balears (COPIB)

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    Amb motiu de la celebració de l’Any Europeu de l’Envelliment Actiu i la Solidaritat Intergeneracional, la Vocalia de Psicologia de l’Envelliment del Col·legi Oficial de Psicologia de les Illes Balears (COPIB) va organitzar un programa molt complet d’activitats al llarg de tot l’any amb l’objectiu de fer visible el rol del psicòleg i la contribució de la psicologia en l’envelliment actiu, promoure un envelliment saludable i, al mateix temps, detectar amb les experiències pilot aspectes a tenir en compte per a la intervenció en les persones grans integrades en una societat intergeneracional. Com a resultat de la participació en les activitats proposades, de les quals s’han exposat les més significatives (revisió de memòria, relaxació i relació intergeneracional), les persones que varen gaudir de les iniciatives varen manifestar que havien adquirit més consciència del seu propi procés d’envelliment com a experiència de creixement constant i varen comprendre una mica més la labor del psicòleg en l’envelliment.Con motivo de la celebración del Año Europeo del Envejecimiento Activo y la Solidaridad Intergeneracional, la Vocalía de Psicología del Envejecimiento del Colegio Oficial de Psicólogos de les Illes Balears (COPIB ) organizó un completo programa de actividades a lo largo de todo el año con el objetivo de hacer visible el rol del psicólogo y la contribución de la psicología en el envejecimiento activo y la promoción de un envejecimiento saludable e ir detectando con las experiencias piloto aspectos a tener en cuenta para la intervención en las personas mayores integradas en una sociedad intergeneracional. Como resultado de la participación en las actividades propuestas de las que se han expuesto las más significativas (revisión de memoria, relajación y relación intergeneracional), las personas que aprovecharon las iniciativas manifestaron haber adquirido mayor conciencia de su propio proceso de envejecimiento como experiencia de crecimiento constante y comprendieron un poco más la labor del psicólogo en el envejecimiento

    Can sensory boar taint levels be explained by fatty acid composition and emitted volatile organic compounds in addition to androstenone and skatole content?

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    peer reviewedThis study aimed at understanding which molecules were responsible for the differences existing in boar taint sensory evaluation. The latter was therefore linked to the results of skatole and androstenone chemical analyses, fatty acid composition and VOC profiles of heated backfat. This study confirmed that some discrepancy exists between chemical analysis and sensory evaluation of tainted backfats. Significant correlations between human nose scores and fatty acid composition were not revealed. Strong correlations between emissions and contents in skatole and androstenone were found. Oxidation products of polyunsaturated fatty acids, with fatty odor descriptors, were found to be more present in the VOC profiles of boar fat considered untainted through the human nose methodology. Weak coefficient of determination for partial least square regression indicates that other factors, yet unknown, are responsible for sensory evaluation outcomes. These findings hence support the idea that high human nose score is mainly due to boar taint compounds rather than general differences in VOC profiles. Keywords: boar taint, androstenone, skatole, human nose, fatty acid, VO

    Prosthetic shoulder joint infection by Cutibacterium acnes: does rifampin improve prognosis? a retrospective, multicenter, observational study.

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    This retrospective, multicenter observational study aimed to describe the outcomes of surgical and medical treatment of C. acnes-related prosthetic joint infection (PJI) and the potential benefit of rifampin-based therapies. Patients with C. acnes-related PJI who were diagnosed and treated between January 2003 and December 2016 were included. We analyzed 44 patients with C. acnes-related PJI (median age, 67.5 years (IQR, 57.3-75.8)); 75% were men. The majority (61.4%) had late chronic infection according to the Tsukayama classification. All patients received surgical treatment, and most antibiotic regimens (43.2%) included β-lactam. Thirty-four patients (87.17%) were cured; five showed relapse. The final outcome (cure vs. relapse) showed a nonsignificant trend toward higher failure frequency among patients with previous prosthesis (OR: 6.89; 95% CI: 0.80-58.90) or prior surgery and infection (OR: 10.67; 95% IC: 1.08-105.28) in the same joint. Patients treated with clindamycin alone had a higher recurrence rate (40.0% vs. 8.8%). Rifampin treatment did not decrease recurrence in patients treated with β-lactams. Prior prosthesis, surgery, or infection in the same joint might be related to recurrence, and rifampin-based combinations do not seem to improve prognosis. Debridement and implant retention appear a safe option for surgical treatment of early PJI

    The Different Microbial Etiology of Prosthetic Joint Infections According to Route of Acquisition and Time After Prosthesis Implantation, Including the Role of Multidrug-Resistant Organisms

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    The aim of our study was to characterize the etiology of prosthetic joint infections (PJIs)-including multidrug-resistant organisms (MDRO)-by category of infection. A multicenter study of 2544 patients with PJIs was performed. We analyzed the causative microorganisms according to the Tsukayama's scheme (early postoperative, late chronic, and acute hematogenous infections (EPI, LCI, AHI) and "positive intraoperative cultures" (PIC)). Non-hematogenous PJIs were also evaluated according to time since surgery: 12 months. AHIs were mostly caused by Staphylococcus aureus (39.2%) and streptococci (30.2%). EPIs were characterized by a preponderance of virulent microorganisms (S. aureus, Gram-negative bacilli (GNB), enterococci), MDROs (24%) and polymicrobial infections (27.4%). Conversely, coagulase-negative staphylococci (CoNS) and Cutibacterium species were predominant in LCIs (54.5% and 6.1%, respectively) and PICs (57.1% and 15.1%). The percentage of MDROs isolated in EPIs was more than three times the percentage isolated in LCIs (7.8%) and more than twice the proportion found in AHI (10.9%). There was a significant decreasing linear trend over the four time intervals post-surgery for virulent microorganisms, MDROs, and polymicrobial infections, and a rising trend for CoNS, streptococci and Cutibacterium spp. The observed differences have important implications for the empirical antimicrobial treatment of PJIs.Acknowledgments: This work was supported by the Instituto de Salud Carlos III, Spanish Ministry of Economy and Competitiveness (grant number PI15/1026) (Co-funded by European Regional Development Fund/European Social Fund "Investing in your future"). REIPI (Spanish Network for Research in Infectious Disease) is supported by the Instituto de Salud Carlos III, Spanish Ministry of Economy and Competitiveness, and by the European Development Regional Fund “A way to achieve Europe”

    Clustering COVID-19 ARDS patients through the first days of ICU admission. An analysis of the CIBERESUCICOVID Cohort

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    Background Acute respiratory distress syndrome (ARDS) can be classified into sub-phenotypes according to different inflammatory/clinical status. Prognostic enrichment was achieved by grouping patients into hypoinflammatory or hyperinflammatory sub-phenotypes, even though the time of analysis may change the classification according to treatment response or disease evolution. We aimed to evaluate when patients can be clustered in more than 1 group, and how they may change the clustering of patients using data of baseline or day 3, and the prognosis of patients according to their evolution by changing or not the cluster.Methods Multicenter, observational prospective, and retrospective study of patients admitted due to ARDS related to COVID-19 infection in Spain. Patients were grouped according to a clustering mixed-type data algorithm (k-prototypes) using continuous and categorical readily available variables at baseline and day 3.Results Of 6205 patients, 3743 (60%) were included in the study. According to silhouette analysis, patients were grouped in two clusters. At baseline, 1402 (37%) patients were included in cluster 1 and 2341(63%) in cluster 2. On day 3, 1557(42%) patients were included in cluster 1 and 2086 (57%) in cluster 2. The patients included in cluster 2 were older and more frequently hypertensive and had a higher prevalence of shock, organ dysfunction, inflammatory biomarkers, and worst respiratory indexes at both time points. The 90-day mortality was higher in cluster 2 at both clustering processes (43.8% [n = 1025] versus 27.3% [n = 383] at baseline, and 49% [n = 1023] versus 20.6% [n = 321] on day 3). Four hundred and fifty-eight (33%) patients clustered in the first group were clustered in the second group on day 3. In contrast, 638 (27%) patients clustered in the second group were clustered in the first group on day 3.Conclusions During the first days, patients can be clustered into two groups and the process of clustering patients may change as they continue to evolve. This means that despite a vast majority of patients remaining in the same cluster, a minority reaching 33% of patients analyzed may be re-categorized into different clusters based on their progress. Such changes can significantly impact their prognosis

    The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

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    Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

    Fostering English-taught higher education programs in a Spanish university: the "TechEnglish" innovative project

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    In recent years, coinciding with adjustments to the Bologna process, many European universities have attempted to improve their international profile by increasing course offerings in English. According to the Institute of International Education (IIE), Spain has notably increased its English-taught higher education programs, ranking fifth in the list of European countries by number of English-taught Master's programs in 2013. This article presents the goals and preliminary results of an on-going innovative education project (TechEnglish) that aims to promote course offerings in English at the Technical University of Madrid (Universidad Politécnica de Madrid, UPM). The UPM is the oldest and largest of all Technical Universities in Spain. It offers graduate and postgraduate programs that cover all the engineering disciplines as well as architecture. Currently, the UPM has no specific bilingual/multilingual program to promote teaching in English, although there is an Educational Model Whitepaper (with a focus on undergraduate degrees) that promotes the development of activities like an International Semester or a unique shared curriculum. The TechEnglish project is an attempt to foster courses taught in English at 7 UPM Technical Schools, including students and 80 faculty members. Four tasks were identified: (1) to design a university wide framework to increase course offerings, (2) to identify administrative difficulties, (3) to increase visibility of courses offered, and (4) to disseminate the results of the project. First, to design a program we analyzed existing programs at other Spanish universities, and other projects and efforts already under way at the UPM. A total of 13 plans were analyzed and classified according to their relation with students (learning), professors (teaching), administration, course offerings, other actors/institutions within the university (e.g., language departments), funds and projects, dissemination activities, mobility plans and quality control. Second, to begin to identify administrative and organizational difficulties in the implementation of teaching in English, we first estimated the current and potential course offerings at the undergraduate level at the UPM using a survey (student, teacher and administrative demand, level of English and willingness to work in English). Third, to make the course offerings more attractive for both Spanish and international students we examined the way the most prestigious universities in Spain and in Europe try to improve the visibility of their academic offerings in English. Finally, to disseminate the results of the project we created a web page and a workspace on the Moodle education platform and prepared conferences and workshops within the UPM. Preliminary results show that increasing course offerings in English is an important step to promote the internationalization of the University. The main difficulties identified at the UPM were related to how to acknowledge/certify the departments, teachers or students involved in English courses, how students should register for the courses, how departments should split and schedule the courses (Spanish and English), and the lack of qualified personnel. A concerted effort could be made to increase the visibility of English-taught programs offered on-line

    Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

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    Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio
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