Model based adaptive direct power control for three-level NPC converters

In this work, a Model Based Adaptive Direct Power Control (MB-ADPC) with constant switching frequency for Three-Phase Three-Level Neutral Point Clamped (3L-NPC) converters is proposed. The rectifier and inverter operation mode are used to illustrate the flexibility of the proposed MB-ADPC controller. The control design process is based on the continuous averaged model of the system. Depending on the operation mode different control objectives have to be guaranteed. The proposed controller ensures the voltage regulation of the dc-link capacitors for the rectifier operation mode and to achieve voltage balance in the dc-link capacitors and the active and reactive power tracking for the rectifier and inverter operation modes. In addition, adaptive techniques are used to avoid system parameters uncertainties as smoothing inductors and grid frequency values. This work shows that the application of advanced control strategies based on the system model allows enhancing the performance of the overall system. The details of the controllers design process and the experimental results using a 50 kVA Three-Phase Three-Level NPC prototype are presented in this paper validating the proposed controllers

Leisure-time physical activity and cardiometabolic risk among children and adolescents ଝ Leisure-time activity and cardiometabolic risk PALAVRAS-CHAVE

Abstract Objective: To assess the effect of Leisure-time physical activity (LTPA) on cardiometabolic risk by nutritional status in Mexican children and adolescents. Methods: This was a cross-sectional study conducted with 1,309 participants aged between 5 and 17 years. Nutritional status was classified according to the BMI Z-score by age and gender. A previously validated questionnaire was used to evaluate LTPA; a cardiometabolic risk score was calculated. Multiple linear regression analysis was performed to assess the effect of LTPA on cardiometabolic risk. Results: After adjusting for risk factors, mild LTPA were positively associated with cardiometabolic risk score (␤ Mild vs Intense LTPA : 0.68; 95% CI: 0.18 to 1.18; p for trend = 0.007). This association became stronger when estimated for overweight (␤ Mild vs Intense LTPA : 1.24; 95% CI: 0.24 to 2.24; p for trend = 0.015) and obese participants (␤ Mild vs Intense LTPA : 1.02; 95% CI: 0.07 to 1.97; p for trend = 0.045). Conclusion: Mild LTPA was positively associated with cardiometabolic risk in overweight and obese children and adolescents. Given the emerging childhood obesity epidemic in Mexico, these results may be useful in the design of strategies and programs to increase physical activity levels in order to achieve better health. © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved. Intensa : 1,02; IC 95%: 0,07 a 1,97; P para tendência = 0,045). Conclusão: A AFL leve foi positivamente associada ao escore de risco cardiometabólico em crianças e adolescentes acima do peso e obesos. Considerando a epidemia de obesidade infantil emergente no México, esses resultados poderão ser úteis na elaboração de estratégias e programas para aumentar os níveis de atividade física a fim de obter uma saúde melhor

Leisure-time physical activity and cardiometabolic risk among children and adolescents

OBJECTIVE: To assess the effect of Leisure-time physical activity (LTPA) on cardiometabolic risk by nutritional status in Mexican children and adolescents. METHODS: This was a cross-sectional study conducted with 1,309 participants aged between 5 and 17 years. Nutritional status was classified according to the BMI Z-score by age and gender. A previously validated questionnaire was used to evaluate LTPA; a cardiometabolic risk score was calculated. Multiple linear regression analysis was performed to assess the effect of LTPA on cardiometabolic risk. RESULTS: After adjusting for risk factors, mild LTPA were positively associated with cardiometabolic risk score (ßMildvsIntenseLTPA: 0.68; 95% CI: 0.18 to 1.18; pfortrend = 0.007). This association became stronger when estimated for overweight (ß MildvsIntenseLTPA: 1.24; 95% CI: 0.24 to 2.24; pfortrend = 0.015) and obese participants (ß MildvsIntenseLTPA: 1.02; 95% CI: 0.07 to 1.97; pfortrend= 0.045) CONCLUSION: Mild LTPA was positively associated with cardiometabolic risk in overweight and obese children and adolescents. Given the emerging childhood obesity epidemic in Mexico, these results may be useful in the design of strategies and programs to increase physical activity levels in order to achieve better health

Phytoestrogen Concentrations in Human Urine as Biomarkers for Dietary Phytoestrogen Intake in Mexican Women

There has been substantial interest in phytoestrogens, because of their potential effect in reducing cancer and heart disease risk. Measuring concentrations of phytoestrogens in urine is an alternative method for conducting epidemiological studies. Our objective was to evaluate the urinary excretion of phytoestrogens as biomarkers for dietary phytoestrogen intake in Mexican women. Participants were 100 healthy women from 25 to 80 years of age. A food frequency questionnaire (FFQ) and a 24 h recall were used to estimate habitual and recent intakes of isoflavones, lignans, flavonols, coumestrol, resveratrol, naringenin, and luteolin. Urinary concentrations were measured by liquid chromatography (HPLC) coupled to mass spectrometry (MS) using the electrospray ionization interface (ESI) and diode array detector (DAD) (HPLC-DAD-ESI-MS). Spearman correlation coefficients were used to evaluate associations between dietary intake and urine concentrations. The habitual consumption (FFQ) of total phytoestrogens was 37.56 mg/day. In urine, the higher compounds were naringenin (60.1 µg/L) and enterolactone (41.7 µg/L). Recent intakes (24 h recall) of isoflavones (r = 0.460, p < 0.001), lignans (r = 0.550, p < 0.0001), flavonoids (r = 0.240, p < 0.05), and total phytoestrogens (r = 0.410, p < 0.001) were correlated to their urinary levels. Total phytoestrogen intakes estimated by the FFQ showed higher correlations to urinary levels (r = 0.730, p < 0.0001). Urinary phytoestrogens may be useful as biomarkers of phytoestrogen intake, and as a tool for evaluating the relationship of intake and disease risk in Mexican women

The pediatric solid organ transplant experience with COVID-19: An initial multi-center, multi-organ case series

The clinical course of COVID-19 in pediatric solid organ transplant recipients remains ambiguous. Though preliminary experiences with adult transplant recipients have been published, literature centered on the pediatric population is limited. We herein report a multi-center, multi-organ cohort analysis of COVID-19-positive transplant recipients ≤ 18 years at time of transplant. Data were collected via institutions' respective electronic medical record systems. Local review boards approved this cross-institutional study. Among 5 transplant centers, 26 patients (62% male) were reviewed with a median age of 8 years. Six were heart recipients, 8 kidney, 10 liver, and 2 lung. Presenting symptoms included cough (n = 12 (46%)), fever (n = 9 (35%)), dry/sore throat (n = 3 (12%)), rhinorrhea (n = 3 (12%)), anosmia (n = 2 (8%)), chest pain (n = 2 (8%)), diarrhea (n = 2 (8%)), dyspnea (n = 1 (4%)), and headache (n = 1 (4%)). Six patients (23%) were asymptomatic. No patient required supplemental oxygen, intubation, or ECMO. Eight patients (31%) were hospitalized at time of diagnosis, 3 of whom were already admitted for unrelated problems. Post-transplant immunosuppression was reduced for only 2 patients (8%). All symptomatic patients recovered within 7 days. Our multi-institutional experience suggests the prognoses of pediatric transplant recipients infected with COVID-19 may mirror those of immunocompetent children, with infrequent hospitalization and minimal treatment, if any, required

La vigilancia de la salud de los trabajadores expuestos al amianto: ejemplo de colaboración entre el Sistema de Prevención de Riesgos Laborales y el sistema Nacional de Salud

El Ministerio de Sanidad y Consumo y las Comunidades Autónomas han diseñado y consensuado con los profesionales sanitarios y las organizaciones empresariales y sindicales representativas un Plan Integral de Vigilancia de la Salud de los Trabajadores que han estado expuestos a Amianto, con el objetivo de garantizar una intervención adecuada, uniforme y armonizada de estos trabajadores en todo el territorio nacional. La elaboración del Programa partió del Grupo de Trabajo de Salud Laboral del Consejo Interterritorial, se enriqueció con las aportaciones del Grupo de Trabajo Amianto de la Comisión Nacional de Seguridad y Salud en el Trabajo, fue consensuado con los profesionales de la medicina y enfermería del trabajo, y fue aprobado por las autoridades sanitarias y laborales. El Programa consta de siete grandes bloques de actividades. Dos años después de aprobado el Programa, el estado de implantación en las Comunidades Autónomas es desigual. Las principales dificultades para su puesta en marcha se encuentran en la elaboración del Registro de expuestos. Un total de 5.778 trabajadores están incluidos en el Registro. 208 trabajadores tienen EPOC, 198 alteraciones pleurales benignas, 8 cáncer de pulmón, 10 mesotelioma y 7 presentan otros cánceres con posible relación con el amianto (gástrico, de laringe y colon)