DC-Voltage-Ratio Control Strategy for Multilevel Cascaded Converters Fed With a Single DC Source

Recently, a multilevel cascaded converter fed with a single DC source has been presented. An analysis of the steady-state working limits of this type of converter is presented in this paper. Limits of the maximum output voltage and the minimum and maximum loading conditions for stable operation of the converter are addressed. In this paper, a way to achieve any DC voltage ratio (inside the stable operation area of the converter) between the H-bridges of the single-DC-source cascaded H-bridge converter is presented. The proposed DC-voltage-ratio control is based on a time-domain modulation strategy that avoids the use of inappropriate states to achieve the DC-voltage-ratio control. The proposed technique is a feedforward-modulation technique which takes into account the actual DC voltage of each H-bridge of the converter, leading to output waveforms with low distortion. In this way, the dc voltage of the floating H-bridge can be controlled while the output voltage has low distortion independently of the desired DC voltage ratio. Experimental results from a two-cell cascaded converter are presented in order to validate the proposed DC-voltage-ratio control strategy and the introduced concepts.Ministerio de Ciencia y Tecnología TEC2006-03863Junta de Andalucía EXC/2005/TIC-117

Validation of the Satisfaction Scale of Basic Psychological Needs in Physical Education with the Incorporation of the Novelty in the Spanish Context

The purpose of the study was to validate to the physical education context, the Spanish version of the Scale of the Satisfaction of Psychological Needs toward the Physical Education classes of Menéndez and Fernández-Rio, with the incorporation of the novelty, since they contemplated its inclusion. In this study, 1444 students participated (mean = 15.34, standard deviation = 1.12) from several schools in Almeria. To analyze the psychometric properties of the scale, several analyses were carried out. The results offered support for both the four-factor structure and the higher-order model called satisfaction. The analysis of invariance with respect to gender showed that the factor structure of the questionnaire was invariant. The Cronbach alpha values were higher than 0.70 in the subscales. The results of this study demonstrated the reliability and validity of the Scale of the Satisfaction of Psychological Needs, with the incorporation of novelty in the Spanish context of Physical Education

Diagnosticand pronostic utility of serum microrna-21 in colorectal cancer

Los microRNAs son estructuras moleculares de 20-22 nucleótidos con actividad post-transcripional que están implicados en la carcinogénesis mediante una regulación genética post-transcripcional. Presentamos un estudio prospectivo donde se determina la expresión sérica de microRNA-21 en pacientes con diagnóstico de adenocarcinoma de colon. MATERIAL Y MÉTODOS. Estudio de cohorte prospectivo de al menos 100 pacientes con diagnóstico de adenocarcinoma de colon, y de al menos 60 pacientes con apendicitis aguda como grupo control. Se realizó el análisis de microRNA-21 sérico mediante PCR de las muestras sanguíneas de los pacientes obtenidas de forma preoperatoria. RESULTADOS. La comparación de la expresión del microRNA-21 sérico fue mayor en los pacientes con cáncer colorrectal que en los pacientes del grupo control, siendo el área bajo la curva de 0,603. En el análisis univariante, la expresión del miR- 21 se relaciona de forma estadísticamente significativa con la recidiva local (p=0,025) y con la mortalidad (p=0,029). En el análisis multivariante también se puso de manifiesto que las expresiones mayores (sobreexpresiones) de miR-21 se relacionaban con una reducción del riesgo derecidiva del 51%, mientras que dicha sobreexpresión se relacionaba con una reducción de mortalidad del 50%. CONCLUSIONES. La expresión del microRNA-21 sérico podría ser considerado como un potencial marcador diagnóstico para el cáncer colorrectal. La expresión sérica del microRNA-21 se correlaciona con la recidiva y mortalidad en el cáncer colorrectal. Nuestros resultados sugieren que el miR-21 sérico es un prometedor marcador diagnóstico y pronóstico, y pone de manifiesto su potencial utilidad clínica en el cáncer colorrectalMicroRNAs (miRNAs) are small, noncoding RNAs that are involved in carcinogenesis through postranscriptional gene regulatory activity. Few studies have focused on the detection of miR-21 in serum rather than in tissue. The current study aimed to measure serum miR-21 expression levels and to evaluate their association with the outcome of colorectal cancer (CRC). METHODS. Blood samples were collected from almost 100 CRC patients undergoing surgery with curative intent, and almost 60 control patients. The expression levels of miR-21 were measured using a quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS. Serum microRNA-21 expression was higher in colorectal cancer patients than in control patients, with a ROC curve of 0.603. A univariate analysis revealed that lower expression levels of serum miR-21 were associated with higher local recurrence (p=0.025) and mortality (p=0.029). A logistic regression analysis demonstrated that the relative overexpression of miR-21 (expression >1) was associated with a 51% reduction in the risk of recurrence. A Cox regression analysis identified that a relative increase in miR-21 expression (>1) was associated with a 50% reduction in the risk of mortality CONCLUSIONS. Serum microRNA-21 expression could be considered as a potential diagnostic marker for colorectal cancer. The expression level of serum miR-21 correlates with the recurrence and mortality of CRC patients. Our results suggest that circulating serum miR-21 is a promising diagnostic and prognostic tumour marker, and they highlight the potential clinical utility of miR-21 in colorectal cancerEl presente estudio ha sido financiado con la ayuda otorgada por la Fundación para la Investigación Sanitaria en Castilla La Mancha (FISCAM) y por la Fundación Mutua Madrileña Investigación Médic

Selective Harmonic Mitigation Technique for Cascaded H-Bridge Converters With Nonequal DC Link Voltages

Multilevel converters have received increased interest recently as a result of their ability to generate high quality output waveforms with a low switching frequency. This makes them very attractive for high power applications. A Cascaded HBridge converter is a multilevel topology which is formed from the series connection of H-Bridge cells. Optimized pulse width modulation techniques such as Selective Harmonic Elimination (SHE-PWM) or Selective Harmonic Mitigation (SHM-PWM) are capable of pre-programming the harmonic profile of the output waveform over a range of modulation indices. Such modulation methods may however not perform optimally if the DC links of the Cascaded H-Bridge Converter are not balanced. This paper presents a new SHM-PWM control strategy which is capable of meeting grid codes even under non-equal DC link voltages. The method is based on the interpolation of different sets of angles obtained for specific situations of imbalance. Both simulation and experimental results are presented to validate the proposed control method

Colorectal cancer carcinogenesis

El cáncer colorrectal representó en el año 2008 el tercer tumor más diagnosticado en España, siendo la segunda neoplasia que causó más fallecimientos. El conocimiento del proceso carcinogenético de este tipo de enfermedad permitirá el descubrimiento de nuevas terapéuticas que conlleven menores tasas de incidencia y mortalidad. El continuo avance en la enfermedad tumoral hace que esta revisión sea una puesta al día en el conocimiento de la carcinogénesis del cáncer colorrectalIn 2008, colorectal cancer represented the third most commonly diagnosed tumor in Spain, and the second tumor that caused more deaths. Knowledge of the carcinogenetic process of this disease will allow the discovery of new therapies involving lower rates of incidence and mortality. The continuous progress in tumor disease makes this review an update on the knowledge of colorectal cancer carcinogenesi

Recovery of betulinic acid from plane tree (Platanus acerifolia L.)

Betulinic acid (3β, hydroxy-lup-20(29)-en-28-oic acid) is a bioactive triterpenic acid which was identified in various botanical sources and in considerable amounts in the bark of plane tree (Platanus acerifolia L.). In this work, the recovery of betulinic acid from plane tree bark was studied using different liquid solvent based extraction methods, namely solid-liquid extraction (SLE), ultrasound assisted extraction (UAE) and pressurized liquid extraction (PLE). Furthermore, preliminary studies of the supercritical fluid extraction (SFE) of plane tree bark are also reported. The liquid solvent based extraction techniques (SLE, UAE and PLE) were carried out using ethanol and ethyl acetate, and produced a recovery of betulinic acid in the range 10-15 mg/g of bark, with concentrations around 25-35% mass. A betulinic acid enrichment in the ethanolic extracts was possible by means of a simple precipitation step adding water. The precipitate contained 42-46% mass of betulinic acid and high recovery (>95%). Increasing the extraction temperature, by means of the PLE assays, has not resulted in an improvement of betulinic acid recovery. The preliminary SFE assays produced lower recoveries of betulinic acid (0.5-8 mg/g) with respect to liquid extraction. The addition of ethanol as cosolvent produced a significant improvement of both betulinic acid recovery and concentration in the SFE extract.This work has been supported by project ALIBIRD-S2009/AGR-1469 from Comunidad Autónoma de Madrid. López-Padilla A. thanks to COLCIENCIAS (568–2012) and Medellin Mayor's Office (Sapiencia/Enlaza Mundos Program, 2013) for the Ph.D. fellowship.Peer Reviewe

Microrna-21 and colorectal cancer

Introducción. Los microRNAs son estructuras moleculares con actividad post-transcripcional que están implicados en la regulación de la expresión genética. Diversos estudios ponen de manifiesto la participación de los microRNAs con distintas funciones fisiológicas, así como con el proceso de la oncogénesis. La expresión de los microRNAs puede verse alterada en las neoplasias por su interacción bien con los genes supresores de tumores, bien con los oncogenes. Discusión. Llevamos a cabo una revisión de la literatura sobre el microRNA-21, poniendo de manifiesto la evidencia existente entre el microRNA-21 y la enfermedad neoplásica, de forma especial con el cáncer colorrectal. Conclusiones. El estado actual de los microRNAs hace necesario continuar con la investigación existente entre la etiopatogenia de las neoplasias y los microRNAs. El conocimiento de la verdadera implicación de los microRNAs en la fisiopatología de la enfermedad neoplásica, permitirá ampliar las supuestas aplicaciones clínicas del miR-21 no sólo a la determinación del pronóstico del cáncer colorrectal, sino también desde el punto de vista diagnóstico al poder diferenciar las lesiones de la mucosa colónicaIntroduction. MicroRNAs are molecular structures with post-transcriptional activity, involved in the gene expression regulation. Several studies have demonstrated the involvement of microRNAs in different physiological functions, as well as in the oncogenesis process. The expression of microRNAs may be altered in the tumors by either interaction with tumor suppressor genes or oncogenes. Discussion. A review of the medical literature on microRNA-21 has been conducted, showing the evidence between microRNA-21 and neoplastic disease, specially with colorectal cancer. Conclusion. The current status of microRNAs makes necessary to continue the investigation of the pathogenesis of cancer and microRNAs. The knowledge of the involvement of microRNAs in the pathophysiology of neoplastic disease, will allow to extend the supposed clinical applications of miR-21 not only to the determination of the prognosis of colorectal cancer, but also for the differential diagnosis of processes of colonic mucosa

Diseño de filtros de canal elípticos y autoEcualizados en banda Ka implementados en guía rectangular plano H

En esta comunicación se presenta un proceso sistemático de diseño de filtros de canal elípticos y autoecualizados en guía de onda rectangular y configuración plano-H en banda Ka. Se pretende desarrollar una alternativa a la configuración clásica dual-mode en guía de onda circular, con el objetivo de abaratar el coste y simplificar el proceso de producción. Para validar la metodología presentada se ha diseñado, fabricado y medido un filtro de orden seis con dos ceros de transmisión a frecuencias finitas para mejorar el rechazo y dos ceros de ecualización para el retardo de grupo. Los resultados experimentales validan el método propuesto

The diagnosis of hereditary angioedema: family caregivers’ experiences

The aim of this study was to understand the experiences of family caregivers in the process of diagnosing hereditary angioedema. An interpretive and qualitative research methodology based on Gadamer’s philosophical hermeneutics was carried out. Data collection took place between May 2015 and August 2016 and included a focus group and in-depth interviews with 16 family caregivers. Two themes define the experiences of family caregivers: “Family life focuses on identifying the problem” and “Discovering and coping with a complex diagnosis.” The process of diagnosis generates fear, anxiety, uncertainty, and incomprehension. Family caregivers are the main support for patients diagnosed with hereditary angioedema. As they share in the patients’ suffering, they need a diagnosis to be established to be able to cope with the disease and offer support. Family health nurses can contribute to improving the coping process in this phase of the disease

Analysis of Fusarium-Common Beans Pathosystem in Aguascalientes, Mexico

In Mexico, high incidences of Fusarium affect common bean (Phaseolus vulgaris L.) production, reducing grain yields due to seedling death and crop standing reductions. Production of resistant germplasm could be an appropriate strategy for grain yield increasing. Bean breeding programs need the former analysis of plant-pathogen pathosystem to perform the selection of segregating populations with improved resistance to root rot pathogens and the best agroecosystem adaptation. Here, we report our results on characterization of genetic variability patterns of Fusarium solani f. sp. phaseoli (FSP) from Aguascalientes, México; the analysis of P. vulgaris germplasm reactions to highly and naturally FSP-infested field and controlled conditions; and the identification of genetic basis of resistance to FSP root rot in segregating common bean populations. Significant genetic variability in FSP isolates from Aguascalientes and other regions of México was found. Also, we found high variation on reactions to FSP root rots, resistance was more frequent on black seed-coated beans, and susceptibility was common in pinto beans. Resistance to FSP in BAT 477 seedlings was associated with one quantitative trait loci (QTL)