59 research outputs found
Entrenador digital para convertidores en aplicaciones docentes
Este proyecto trata de diseñar y crear un convertidor estático de potencia capaz
de controlar distintos accionamientos en aplicaciones docentes. Sería como tener
varios convertidores en uno dependiendo de las conexiones.
Primeramente se realiza una recopilación de información sobre las aplicaciones
que el convertidor puede llegar a controlar, así como las topologías de cada tipo
de convertidor.
A continuación, se estudia todos los dispositivos electrónicos auxiliares como las
fuentes de tensión que alimentan los drivers de disparo y los transductores de
corrientes. También se detallan las características del rectificador trifásico.
A partir de la disposición y estructura de los módulos de IGBT’s indicamos los
esquemas característicos de cada convertidor, para poder ser implementados con
éxito. Se diferencia cada convertidor respecto al tipo de motor que controlan.
Estas conexiones permiten llevar a cabo cada una de las aplicaciones.
Para poder diseñar el convertidor es importante conocer el funcionamiento exacto
del circuito que se va a implementar. Se explica la función de cada elemento que
pertenece al circuito. Gracias a saber realmente cual es el funcionamiento
correcto del circuito se pueden detectar fallos de diseño con menos dificultad.
Uno de los puntos más importantes a realizar en el presente proyecto es el del
diseño de los circuitos impresos de control y de medida. Para realizar un diseño
más competitivo se han empleado herramientas informáticas como es el
programa especializado Altium Designer. Para ejecutar la impresión de los
circuitos impresos se utiliza una fresadora automática que facilita la universidad.
Con esta máquina la precisión es absoluta disminuyendo el porcentaje de
aparición de un posible error no deseado.
Una vez diseñado y creado el convertidor se dispone a hacer las pruebas
pertinentes para validar el funcionamiento correcto de la aplicación. Este punto
sin duda alguna tiene una gran importancia, es donde se refleja todo el trabajo
realizado con anterioridad. El montaje efectuado es el de una fase del convertidor,
debido a la falta de material no se ha podido montar el convertidor al completo. El
trabajo en el laboratorio es muy diverso, se han realizado pruebas con cargas
puramente resistivas, con un motor de corriente continua y con la fase de un
motor de reluctancia autoconmutado. También se ha realizado un control del
sistema mediante el DSP de dSPACE a tiempo real, a partir de Matlab.
Todas las pruebas realizadas en el laboratorio se han estudiado y corroborado,
con lo que podemos validar el buen funcionamiento del convertidor.
En este proyecto también se ha hecho un presupuesto muy aproximado al coste
total de la investigación. También se refleja las conclusiones obtenidas de esta
experiencia.
Por último se repasa la bibliografía utilizada para la ejecución de este proyecto
Blood pressure values and depression in hypertensive individuals at high cardiovascular risk
BACKGROUND: Hypertension and depression are both important risk factors for cardiovascular diseases. Nevertheless, the association of blood pressure on and depression has not been completely established. This study aims to analyze whether depression may influence the control of blood pressure in hypertensive individuals at high cardiovascular risk. METHODS: Cross-sectional study, embedded within the PREDIMED clinical trial, of 5954 hypertensive patients with high cardiovascular risk factor profiles. The relationship between blood pressure control and depression was analyzed. A multivariate analysis (logistic and log-linear regression), adjusting for potential confounders (socio-demographic factors, body mass index, lifestyle, diabetes, dyslipidemia, and antihypertensive treatment), was performed. RESULTS: Depressive patients, with and without antidepressant treatment, had better blood pressure control (OR: 1.28, CI 95%: 1.06-1.55, and OR: 1.30, CI 95%: 1.03-1.65, respectively) than non-depressive ones. Regarding blood pressure levels, systolic blood pressure values (mmHg) were found to be lower in both treated and untreated depressive patients (Log coefficient Beta: -1.59, 95% CI: -0.50 to -2.69 and Log coefficient Beta: -3.49, 95% CI: -2.10 to -4.87, respectively). CONCLUSIONS: Among hypertensive patients at high cardiovascular risk, the control of blood pressure was better in those diagnosed with depression. TRIAL REGISTRATION: Unique identifier: ISRCTN35739639
Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: the PREDIMED study
INTRODUCTION: Prospective studies have consistently suggested that nut consumption is inversely related to fatal and non-fatal coronary heart disease. Limited data are available on the epidemiological associations between nut intake and cardiometabolic risk factors. OBJECTIVE: To evaluate associations between frequency of nut consumption and prevalence of cardiometabolic risk factors [obesity, metabolic syndrome (MetS), type-2 diabetes, hypertension, and dyslipidemia] in a Mediterranean population at high cardiovascular risk. MATERIALS AND METHODS: Cross-sectional study of 7,210 men and women (mean age, 67 y) recruited into the PREDIMED study. MetS was defined by the harmonized ATPIII and IDF criteria. Diabetes and hypertension were assessed by clinical diagnosis and dyslipidemia (high triglycerides, low HDL-cholesterol, and hypercholesterolemia) by lipid analyses. Nut consumption was assessed using a validated food frequency questionnaire and categorized as 3 servings/wk. Control of confounding was done with multivariate logistic regression. RESULTS: Compared to participants consuming 3 servings/wk had lower adjusted odds ratios (OR) for obesity (0.61, 95% confidence interval 0.54 to 0.68; P-trend <0.001), MetS (0.74, 0.65 to 0.85; P-trend<0.001), and diabetes (0.87, 0.78 to 0.99; P-trend = 0.043). Higher nut consumption was also associated with lower risk of the abdominal obesity MetS criterion (OR 0.68, 0.60 to 0.79; P-trend<0.001). No significant associations were observed for the MetS components high blood pressure, dyslipidemia, or elevated fasting glucose. CONCLUSIONS: Nut consumption was inversely associated with the prevalence of general obesity, central obesity, MetS, and diabetes in subjects at high cardiovascular risk
Personalized Interpretation and Clinical Translation of Genetic Variants Associated With Cardiomyopathies
Cardiomyopathies are a heterogeneous group of inherited cardiac diseases characterized by progressive myocardium abnormalities associated with mechanical and/or electrical dysfunction. Massive genetic sequencing technologies allow a comprehensive genetic analysis to unravel the cause of disease. However, most identified genetic variants remain of unknown clinical significance due to incomplete penetrance and variable expressivity. Therefore, genetic interpretation of variants and translation into clinical practice remain a current challenge. We performed retrospective comprehensive clinical assessment and genetic analysis in six families, four diagnosed with arrhythmogenic cardiomyopathy, and two diagnosed with hypertrophic cardiomyopathy (HCM). Genetic testing identified three rare variants (two non-sense and one small indel inducing a frameshift), each present in two families. Although each variant is currently classified as pathogenic and the cause of the diagnosed cardiomyopathy, the onset and/or clinical course differed in each patient. New genetic technology allows comprehensive yet cost-effective genetic analysis, although genetic interpretation, and clinical translation of identified variants should be carefully done in each family in a personalized manner
Oxidative stress is associated with an increased antioxidant defense in elderly subjects: a multilevel approach.
BACKGROUND: Studies of associations between plasma GSH-Px activity and cardiovascular risk factors have been done in humans, and contradictory results have been reported. The aim of our study was to assess the association between the scavenger antioxidant enzyme glutathione peroxidase (GSH-Px) activity in plasma and the presence of novel and classical cardiovascular risk factors in elderly patients. METHODS: We performed a cross-sectional study with baseline data from a subsample of the PREDIMED (PREvención con DIeta MEDiterránea) study in Spain. Participants were 1,060 asymptomatic subjects at high risk for cardiovascular disease (CVD), aged 55 to 80, selected from 8 primary health care centers (PHCCs). We assessed classical CVD risk factors, plasma oxidized low-density lipoproteins (ox-LDL), and glutathione peroxidase (GSH-Px) using multilevel statistical procedures. RESULTS: Mean GSH-Px value was 612 U/L (SE: 12 U/L), with variation between PHCCs ranging from 549 to 674 U/L (Variance = 013.5; P<0.001). Between-participants variability within a PHCC accounted for 89% of the total variation. Both glucose and oxidized LDL were positively associated with GSH-Px activity after adjustment for possible confounder variables (P = 0.03 and P = 0.01, respectively). CONCLUSION: In a population at high cardiovascular risk, a positive linear association was observed between plasma GSH-Px activity and both glucose and ox-LDL levels. The high GSH-Px activity observed when an oxidative stress situation occurred, such as hyperglycemia and lipid oxidative damage, could be interpreted as a healthy defensive response against oxidative injury in our cardiovascular risk population
Primary prevention of cardiovascular disease with a Mediterranean diet
The traditional Mediterranean diet is characterized by a high intake of olive oil, fruit, nuts, vegetables, and cereals; a moderate intake of fish and poultry; a low intake of dairy products, red meat, processed meats, and sweets; and wine in moderation, consumed with meals.1 In observational cohort studies2,3 and a secondary prevention trial (the Lyon Diet Heart Study),4 increasing adherence to the Mediterranean diet has been consistently beneficial with respect to cardiovascular risk.2-4 A systematic review ranked the Mediterranean diet as the most likely dietary model to provide protection against coronary heart disease.5 Small clinical trials have uncovered plausible biologic mechanisms to explain the salutary effects of this food pattern.6-9 We designed a randomized trial to test the efficacy of two Mediterranean diets (one supplemented with extra-virgin olive oil and another with nuts), as compared with a control diet (advice on a low-fat diet), on primary cardiovascular prevention
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Olive oil intake and risk of cardiovascular disease and mortality in the PREDIMED Study
Background: It is unknown whether individuals at high cardiovascular risk sustain a benefit in cardiovascular disease from increased olive oil consumption. The aim was to assess the association between total olive oil intake, its varieties (extra virgin and common olive oil) and the risk of cardiovascular disease and mortality in a Mediterranean population at high cardiovascular risk. Methods: We included 7,216 men and women at high cardiovascular risk, aged 55 to 80 years, from the PREvención con DIeta MEDiterránea (PREDIMED) study, a multicenter, randomized, controlled, clinical trial. Participants were randomized to one of three interventions: Mediterranean Diets supplemented with nuts or extra-virgin olive oil, or a control low-fat diet. The present analysis was conducted as an observational prospective cohort study. The median follow-up was 4.8 years. Cardiovascular disease (stroke, myocardial infarction and cardiovascular death) and mortality were ascertained by medical records and National Death Index. Olive oil consumption was evaluated with validated food frequency questionnaires. Multivariate Cox proportional hazards and generalized estimating equations were used to assess the association between baseline and yearly repeated measurements of olive oil intake, cardiovascular disease and mortality. Results: During follow-up, 277 cardiovascular events and 323 deaths occurred. Participants in the highest energy-adjusted tertile of baseline total olive oil and extra-virgin olive oil consumption had 35% (HR: 0.65; 95% CI: 0.47 to 0.89) and 39% (HR: 0.61; 95% CI: 0.44 to 0.85) cardiovascular disease risk reduction, respectively, compared to the reference. Higher baseline total olive oil consumption was associated with 48% (HR: 0.52; 95% CI: 0.29 to 0.93) reduced risk of cardiovascular mortality. For each 10 g/d increase in extra-virgin olive oil consumption, cardiovascular disease and mortality risk decreased by 10% and 7%, respectively. No significant associations were found for cancer and all-cause mortality. The associations between cardiovascular events and extra virgin olive oil intake were significant in the Mediterranean diet intervention groups and not in the control group. Conclusions: Olive oil consumption, specifically the extra-virgin variety, is associated with reduced risks of cardiovascular disease and mortality in individuals at high cardiovascular risk. Trial registration This study was registered at controlled-trials.com (http://www.controlled-trials.com/ISRCTN35739639). International Standard Randomized Controlled Trial Number (ISRCTN): 35739639. Registration date: 5 October 2005
Impact of psychosocial factors on cardiovascular morbimortality: a prospective cohort study
Abstract BACKGROUND: Whilst it is well known that psychosocial determinants may contribute to cardiovascular diseases (CVD), data from specific groups are scarce. The present study aims to determine the contribution of psychosocial determinants in increasing the risk of cardiovascular events (myocardial infarction and stroke), and death from CVD, in a high risk adult population. METHODS: Longitudinal prospective study of 7263 patients (57.5% women), mean age 67.0 (SD 6.2) free from CVD but at high risk, with a median follow-up of 4.8 years (from October 2003 to December 2010). The Hazard Ratios (HRs) of cardiovascular events (myocardial infarction, stroke, and death from cardiovascular causes) related to educational attainment, diagnosed depression (based on medical records), and low social support (number of people living in the household) were estimated by multivariate Cox regression models. RESULTS: Stroke incidence was associated with low educational level in the whole population (HR: 1.83, 95% CI: 1.09-3.09), and especially in men (HR: 2.11, 95% CI 1.09-4.06). Myocardial infarction and CVD mortality were not associated with any of the psychosocial factors considered. CONCLUSION: Adults with low educational level had a higher risk of stroke. Depression and low social support were not associated with CVD incidence. TRIAL REGISTRATION: Clinical trial registration information unique identifier: ISRCTN35739639
Discerning the Ambiguous Role of Missense TTN Variants in Inherited Arrhythmogenic Syndromes
The titin gene (TTN) is associated with several diseases, including inherited arrhythmias. Most of these diagnoses are attributed to rare TTN variants encoding truncated forms, but missense variants represent a diagnostic challenge for clinical genetics. The proper interpretation of genetic data is critical for translation into the clinical setting. Notably, many TTN variants were classified before 2015, when the American College of Medical Genetics and Genomics (ACMG) published recommendations to accurately classify genetic variants. Our aim was to perform an exhaustive reanalysis of rare missense TTN variants that were classified before 2015, and that have ambiguous roles in inherited arrhythmogenic syndromes. Rare missense TTN variants classified before 2015 were updated following the ACMG recommendations and according to all the currently available data. Our cohort included 193 individuals definitively diagnosed with an inherited arrhythmogenic syndrome before 2015. Our analysis resulted in the reclassification of 36.8% of the missense variants from unknown to benign/likely benign. Of all the remaining variants, currently classified as of unknown significance, 38.3% showed a potential, but not confirmed, deleterious role. Most of these rare missense TTN variants with a suspected deleterious role were identified in patients diagnosed with hypertrophic cardiomyopathy. More than 35% of the rare missense TTN variants previously classified as ambiguous were reclassified as not deleterious, mainly because of improved population frequencies. Despite being inconclusive, almost 40% of the variants showed a potentially deleterious role in inherited arrhythmogenic syndromes. Our results highlight the importance of the periodical reclassification of rare missense TTN variants to improve genetic diagnoses and help increase the accuracy of personalized medicine
Association of lifestyle factors and inflammation with sarcopenic obesity: data from the PREDIMED‐Plus trial
Background: Sarcopenia is a progressive age-related skeletal muscle disorder associated with increased likelihood of adverse outcomes. Muscle wasting is often accompanied by an increase in body fat, leading to ‘sarcopenic obesity’. The aim of the present study was to analyse the association of lifestyle variables such as diet, dietary components, physical activity (PA), body composition, and inflammatory markers, with the risk of sarcopenic obesity. Methods: A cross-sectional analysis based on baseline data from the PREDIMED-Plus study was performed. A total of 1535 participants (48% women) with overweight/obesity (body mass index: 32.5 ± 3.3 kg/m2; age: 65.2 ± 4.9 years old) and metabolic syndrome were categorized according to sex-specific tertiles (T) of the sarcopenic index (SI) as assessed by dual-energy X-ray absorptiometry scanning. Anthropometrical measurements, biochemical markers, dietary intake, and PA information were collected. Linear regression analyses were carried out to evaluate the association between variables. Results: Subjects in the first SI tertile were older, less physically active, showed higher frequency of abdominal obesity and diabetes, and consumed higher saturated fat and less vitamin C than subjects from the other two tertiles (all P < 0.05). Multiple adjusted linear regression models evidenced significant positive associations across tertiles of SI with adherence to the Mediterranean dietary score (P-trend < 0.05), PA (P-trend < 0.0001), and the 30 s chair stand test (P-trend < 0.0001), whereas significant negative associations were found with an inadequate vitamin C consumption (P-trend < 0.05), visceral fat and leucocyte count (all P-trend < 0.0001), and some white cell subtypes (neutrophils and monocytes), neutrophil-tolymphocyte ratio, and platelet count (all P-trend < 0.05). When models were additionally adjusted by potential mediators (inflammatory markers, diabetes, and waist circumference), no relevant changes were observed, only dietary variables lost significance
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