Simulación y fabricación de piezas pulvimetalúrgicas mediante consolidación eléctrica con corriente de media frecuencia

Objetivos: La Tesis se centra en el desarrollo y simulación de una nueva tecnología de consolidación pulvimetalúrgica rápida aplicable a polvos metálicos. Para lograr la rapidez deseable se propone una modalidad de consolidación eléctrica que aprovecha la tecnología de media frecuencia, empleada ya con éxito en el campo de la soldadura. Los objetivos concretos que se persiguen con el trabajo que se va a llevar a cabo son: Desarrollo de una máquina de sinterización por resistencia eléctrica de media frecuencia (SRE-MF) partiendo del novedoso equipamiento desarrollado para las aplicaciones de la soldadura por resistencia de media frecuencia. El desarrollo será a escala de laboratorio, y para la etapa de potencia de 100 kVA y 1500 daN; Fabricación de piezas de distintos materiales (polvos de hierro, aluminio y ní-quel); Simulación del proceso de SRE-MF con el objetivo principal de conocer la dis-tribución de temperaturas dentro de los compactos; información que es completamente inaccesible desde el punto de vista experimental. En el capítulo 1se recoge una breve introducción al área de in-vestigación en la cual se enmarca esta Tesis, así como los objetivos principales del trabajo desarrollado. En el Capítulo 2 se describe el fundamento teórico del método de fabricación de pie-zas en el que se ha trabajado para el desarrollo de esta Tesis, basado en la sinterización por paso directo de corriente eléctrica empleando media frecuencia, SRE-MF. Además de una breve descripción de la evolución histórica de estas técnicas, se explican las características básicas que diferencian esta novedosa técnica de consolidación de polvos metálicos del resto de métodos de sinterización empleando corriente eléctrica. Asimismo, se describe el modelo teórico adoptado para llevar a cabo las simulaciones del proceso. En el Capítulo 3 se explica con detalle el equipo utilizado para realizar las experien-cias. Además de la descripción de la máquina de soldadura empleada, se explican las modi-ficaciones llevadas a cabo sobre esta para adaptarla a la técnica de SRE-MF, y el conjunto de elementos adicionales empleados para la ejecución de las experiencias. El conjunto de procedimientos experimentales seguidos para el trabajo desarrollado en esta Tesis se describe en el Capítulo 4. En primer lugar, se detallan las técnicas emplea-das en la caracterización de los polvos empleados como material de partida. Por otra parte, se describe el protocolo seguido para la realización de experiencias SRE-MF, así como la caracterización llevada a cabo para los compactos obtenidos mediante esta técnica de con-solidación. El Capítulo 5 describe las características principales de los materiales de partida: cuatro tipos de polvos metálicos, elegidos para la realización de las experiencias de SRE-MF de esta investigación. Además, se incluye la descripción del material empleado para la lubricación de la matriz en las experiencias de sinterización. En el Capítulo 6 se recogen y discuten los resultados obtenidos para todas las expe-riencias de SRE-MF, llevadas a cabo con cada uno de los materiales de partida: polvos de hierro, aluminio y níquel. En primer lugar, se describen las condiciones de las experiencias realizadas con cada uno de los polvos. A continuación, se explican los resultados obtenidos en cada una de ellas, tanto el comportamiento del polvo durante su proceso de consolida-ción, como las propiedades del compacto final. Por último, se recogen los resultados de la serie de simulaciones llevadas a cabo. Y, finalmente, en el Capítulo 7 se resumen las conclusiones a las que se ha llegado tras el análisis y discusión del conjunto de resultados obtenidos en el presente trabaj

Últimos avances en el tratamiento de la ambliopía

La ambliopía es el desarrollo anormal del sistema visual producido por una alteración del córtex visual que provoca una pérdida de agudeza visual, entre otras funciones visuales y suele aparecer desde el nacimiento hasta los 7-8 años. La presente revisión bibliográfica pretende comparar los tratamientos tradicionales o pasivos respecto a los nuevos tratamientos binoculares o activos

Projecting wildfire occurrence at regional scale from Land Use/Cover and climate change scenarios

LUC4FIRE: Project funded by the Spanish Ministry of Science, Innovation and Universities (CSO2015-73407-JIN)

Patient Expectations and Health-Related Quality of Life Outcomes Following Total Joint Replacement

AbstractObjectivesPatient psychological factors have been linked to health-related quality of life (HRQoL) outcomes after total joint replacement (TJR). We evaluated the relationship between patient expectations before TJR, their fulfillment and HRQoL outcomes at 3 and 12 months after surgery.MethodsConsecutive patients preparing for TJR of the knee or hip due to primary osteoarthritis in 15 hospitals in Spain were recruited for the study. Patients completed questionnaires before surgery, and 3 and 12 months afterward: five questions about expectations before surgery and their fulfillment at 3 and 12 months; three HRQoL instruments—Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form 12 (SF-12), and European Quality of Life Instrument (EQ-5D); as well as questions about sociodemographic information. Student's t test was used to assess the relationship between fulfillment of expectations and gains in HRQoL.ResultsA total of 881 patients took part in the study. Preintervention expectations for TJR ranged from 85% to 86% of patients, with high expectations for pain relief and ability to walk to 70% with high expectations about interacting with others. Patients who reported having fulfilled their expectations at 3 and 12 months had significantly greater gains in HRQoL than those who did not. Besides, we observed a statistically significant improvement in the percentage of patients who fulfill their expectations from 3 to 12 months.ConclusionsPatients have high expectations for the benefits of TJR, and those who fulfill their expectations have greater gains in HRQoL assessing by SF-12, WOMAC and EQ-5D. Health-care providers should help their patients develop realistic expectations about the impact of TJR

Empagliflozin reduces vascular damage and cognitive impairment in a mixed murine model of Alzheimer's disease and type 2 diabetes

Background Both Alzheimer's disease (AD) and type 2 diabetes (T2D) share common pathological features including inflammation, insulin signaling alterations, or vascular damage. AD has no successful treatment, and the close relationship between both diseases supports the study of antidiabetic drugs to limit or slow down brain pathology in AD. Empagliflozin (EMP) is a sodium-glucose co-transporter 2 inhibitor, the newest class of antidiabetic agents. EMP controls hyperglycemia and reduces cardiovascular comorbidities and deaths associated to T2D. Therefore, we have analyzed the role of EMP at the central level in a complex mouse model of AD-T2D. Methods We have treated AD-T2D mice (APP/PS1xdb/db mice) with EMP 10 mg/kg for 22 weeks. Glucose, insulin, and body weight were monthly assessed. We analyzed learning and memory in the Morris water maze and the new object discrimination test. Postmortem brain assessment was conducted to measure brain atrophy, senile plaques, and amyloid-beta levels. Tau phosphorylation, hemorrhage burden, and microglia were also measured in the brain after EMP treatment. Results EMP treatment helped to maintain insulin levels in diabetic mice. At the central level, EMP limited cortical thinning and reduced neuronal loss in treated mice. Hemorrhage and microglia burdens were also reduced in EMP-treated mice. Senile plaque burden was lower, and these effects were accompanied by an amelioration of cognitive deficits in APP/PS1xdb/db mice. Conclusions Altogether, our data support a feasible role for EMP to reduce brain complications associated to AD and T2D, including classical pathological features and vascular disease, and supporting further assessment of EMP at the central level

A quasi-elastic aquifer deformational behavior: Madrid aquifer case study

The purpose of this paper is to analyze the quasi-elastic deformational behavior that has been induced by groundwater withdrawal of the Tertiary detrital aquifer of Madrid (Spain). The spatial and temporal evolution of ground surface displacement was estimated by processing two datasets of radar satellite images (SAR) using Persistent Scatterer Interferometry (PSI). The first SAR dataset was acquired between April 1992 and November 2000 by ERS-1 and ERS-2 satellites, and the second one by the ENVISAT satellite between August 2002 and September 2010. The spatial distribution of PSI measurements reveals that the magnitude of the displacement increases gradually towards the center of the well field area, where approximately 80 mm of maximum cumulated displacement is registered. The correlation analysis made between displacement and piezometric time series provides a correlation coefficient greater than 85% for all the wells. The elastic and inelastic components of measured displacements were separated, observing that the elastic component is, on average, more than 4 times the inelastic component for the studied period. Moreover, the hysteresis loops on the stress–strain plots indicate that the response is in the elastic range. These results demonstrate the quasi-elastic behavior of the aquifer. During the aquifer recovery phase ground surface uplift almost recovers from the subsidence experienced during the preceding extraction phase. Taking into account this unique aquifer system, a one dimensional elastic model was calibrated in the period 1997–2000. Subsequently, the model was used to predict the ground surface movements during the period 1992–2010. Modeled displacements were validated with PSI displacement measurements, exhibiting an error of 13% on average, related with the inelastic component of deformation occurring as a long-term trend in low permeability fine-grained units. This result further demonstrates the quasi-elastic deformational behavior of this unique aquifer system.This work was developed during Pablo Ezquerro research stay within the Geohazards InSAR laboratory and Modeling group of the Instituto Geológico y Minero de España in the framework of DORIS project (Ground Deformation Risk Scenarios: an Advanced Assessment Service) funded by the EC-GMES-FP7 initiative (Grant Agreement nº 242212). This work has been also supported by the Spanish Ministry of Science and Research (MICINN) under project TEC2011-28201-C02-02 and EU FEDER. Additional funding was obtained from Spanish Research Program through the project ESP2013-47780-C2-2-R

Biomarkers of Exposure to Zearalenone in In Vivo and In Vitro Studies

The measurement of human exposure to mycotoxins is necessary for its association with adverse health effects. This exposure is usually estimated from contamination levels of foodstuffs, which are the primary source of toxin exposure, and data on food consumption patterns. However, variations in contamination level, intestinal absorption, toxin distribution, and excretion lead to individual variations in toxin exposure that can be more readily measured with a biomarker. This review deals with the latest literature information about ZEN biomarkers in humans, animals, and cell line cultures. Their presence in urine, biomarkers that have effects in the kidney, liver, reproductive system and blood and biomarkers of cell response have been reported. It has highlighted the importance of determining a-zearalenol and ß-zearalenol biomarkers to estimate the probable dietary intake (PDI) of a specific population or to characterize the severity of exposure to ZEN in animals or cell lines. a-ZEL and ß-ZEL are cytotoxic by inhibiting cell proliferation, total protein and DNA syntheses, in this sense, an induction of expression proteins Hsp27 and Hsp70 was observed, and an increase in gene expression (TLR4, NF-kBp65, TNF-a, IL-1ß, IL-6, IL-8, MGMT, a-GST, Hsp70, Nrf2, L-Fabp, HO-1, MAPK8), the determination of which indicates an oxidative stress effect. The integrity of the cell or tissue membrane is assessed by lactate dehydrogenase (LDH), which increase at exposure of ZEN (84.2 µM), and the proportions of some fatty acids of the renal tissue membrane were increased at treatments with ZEN. This review allows starting future studies of animal and population exposure in parallel with those of health effects works. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Multi-step histogram based outlier scores for unsupervised anomaly detection: ArcelorMittal engineering dataset case of study

Anomaly detection is the task of detecting samples that behave differently from the rest of the data or that include abnormal values. Unsupervised anomaly detection is the most common scenario, which implies that the algorithms cannot train with a labeled input and do not know the anomaly behavior beforehand. Histogram-based methods are one of the most approaches in unsupervised anomaly detection, remarking a good performance and a low runtime. Despite the good performance, histogram-based anomaly detectors are not capable of processing data flows while updating their knowledge and cannot deal with a high amount of samples. In this paper, we propose a new histogram-based approach for addressing the aforementioned problems by introducing the ability to update the information inside a histogram. We have applied these strategies to design a new algorithm called Multi-step Histogram Based Outlier Scores (MHBOS), including five new histogram update mechanisms. The results have shown the performance and validity of MHBOS as well as the proposed strategies in terms of performance and computing times.Ministry of Science and Technology under project PID2020-119478 GB-I00Contract UGR-AM OTRI-426Andalusian Excellence project P18-FR-496Spanish Ministry of Science under the FPU Programme 998758-201

A prospective study of the association of patient expectations with changes in health-related quality of life outcomes, following total joint replacement

BACKGROUND: Patient expectations regarding surgery may be related to outcomes in total joint replacement (TJR). The aim of this study was to determine the association of patient expectations with health related quality of life (HRQoL) outcomes measured by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form 12 (SF-12) and satisfaction with current symptoms measured on a 4-point Likert scale, one year after surgery, adjusting for Body Mass Index (BMI), age, gender, joint, education, previous intervention and baseline scores. METHODS: Consecutive patients preparing for TJR of the knee or hip due to primary osteoarthritis (OA) in 15 hospitals in Spain were recruited for the study. Patients completed questionnaires before surgery and 12 months afterwards: five questions about expectations before surgery; an item to measure satisfaction; two HRQoL instruments—WOMAC and SF-12; as well as questions about sociodemographic information. To determine the association of patient expectations at baseline, with changes in HRQoL 12 months after surgery and with satisfaction, general linear models and logistic regression analysis were performed. RESULTS: A total of 892 patients took part in the study. Patients who had higher pain relief or ability to walk expectations improved more in HRQoL at 12 months. Moreover, patients with high daily activity expectations were more satisfied. CONCLUSIONS: Patients with higher baseline expectations for TJR, improved more in HRQoL at one year and had more likelihood to be satisfied than patients with lower expectations, adjusted for BMI, age, gender, joint, education, previous intervention and HRQoL baseline scores

Approximate Profile Maximum Likelihood

We propose an efficient algorithm for approximate computation of the profile maximum likelihood (PML), a variant of maximum likelihood maximizing the probability of observing a sufficient statistic rather than the empirical sample. The PML has appealing theoretical properties, but is difficult to compute exactly. Inspired by observations gleaned from exactly solvable cases, we look for an approximate PML solution, which, intuitively, clumps comparably frequent symbols into one symbol. This amounts to lower-bounding a certain matrix permanent by summing over a subgroup of the symmetric group rather than the whole group during the computation. We extensively experiment with the approximate solution, and find the empirical performance of our approach is competitive and sometimes significantly better than state-of-the-art performance for various estimation problems