Variable-Angle Phase-Shifted PWM for Multilevel Three-Cell Cascaded H-bridge Converters

Multilevel cascaded H-bridge converters have become a mature technology for applications where high-power medium ac voltages are required. Normal operation of multilevel cascaded H-bridge converters assumes that all power cells have the same dc voltage, and each power cell generates the same voltage averaged over a sampling period using a conventional phase-shifted pulse width modulation (PWM) technique. However, this modulation method does not achieve good results under unbalanced operation per H-bridge in the power converter, which may happen in grid-connected applications such as photovoltaic or battery energy storage systems. In the paper, a simplified mathematical analysis of the phase-shifted PWM technique is presented. In addition, a modification of this conventional modulation method using variable shift angles between the power cells is introduced. This modification leads to the elimination of harmonic distortion of low-order harmonics due to the switching (triangular carrier frequency and its multiples) even under unbalanced operational conditions. The analysis is particularized for a three-cell cascaded H-bridge converter, and experimental results are presented to demonstrate the good performance of the proposed modulation method

Heterolytic H2 activation on a carbene-ligated rhodathiaborane promoted by isonido-nido cage opening

A new mechanism of H2 activation is reported to occur on a carbene-ligated rhodathiaborane that features metal-thiaborane bifunctional synergistic effects. The key is the creation of vacant coordination sites by an isonido-nido structural transformation leading to the heterolytic H-H bond splitting. © 2013 The Royal Society of Chemistry.We gratefully acknowledge the Spanish Ministry of Science and Innovation (CTQ2009-10132, CSD2009-00050, and CSD2006-0015, CTQ2012-35665) for financial support. B.C. thanks the ‘‘Diputación General de Aragón’’ for a pre-doctoral scholarship.Peer Reviewe

Estudio de la reactividad de complejos de rodio con un silano funcionalizado.

La reacción de silanos funcionalizados de tipo (piridín-2-iloxi)dialquilsilano con complejos de metales de transición en bajo estado de oxidación da lugar a la formación de especies metálicas con ligandos monoaniónicos bidentados de tipo (piridín-2-iloxi)dialquilsililo que presentan una gran versatilidad electrónica y estérica. La interacción metal-silicio en este tipo de compuestos es de gran interés debido a que se trata de una situación de enlace intermedia entre silileno estabilizado por base y sililo. En este TFG se ha estudiado la reactividad de (4-metilpiridin-2-iloxi)dimetilsilano con complejos de rodio (I), en concreto el rodatioborano de 11 vertices tipo nido [8,8-(PPh3)2-nido-8-Rh(SB9H10)] y el compuesto [RhCl(PPh3)3]. En el primer caso se ha obtenido un nuevo complejo caracterizado como un rodatioborano de 11 vertices [8-(PPh3)-8,8-{κ2-Si,Si-(SiNSi)}-nido-8-Rh-(SB9H11)] que presenta un ligando bis-silileno coordinado al rodio, mientras que en la reacción con el catalizador de Wilkinson se ha formado un complejo que ha sido caracterizado como la especie de rodio (III) [Rh(H)(Cl)(κ2-NSi)(PPh3)]. Este complejo ha demostrado tener un comportamiento interesante en disolución. Resultados preliminares sugieren que la formación del ligando bis-silileno en la reacción con el rodatioborano viene determinada por la acción del ligando tioborano [SB9H10].<br /

Superhydrophobic supported Ag-NPs@ZnO-nanorods with photoactivity in the visible range

In this article we present a new type of 1D nanostructures consisting of supported hollow ZnO nanorods (NRs) decorated with Ag nanoparticles (NPs). The 3D reconstruction by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) electron tomography reveals that the Ag NPs are distributed along the hollow interior of the ZnO NRs. Supported and vertically aligned Ag-NPs@ZnO-NRs grow at low temperature (135 °C) by plasma enhanced chemical vapour deposition on heterostructured substrates fabricated by sputtered deposition of silver on flat surfaces of Si wafers, quartz slides or ITO. The growth mechanisms of these structures and their wetting behavior before and after visible light irradiation are critically discussed. The as prepared surfaces are superhydrophobic with water contact angles higher than 150°. These surfaces turn into superhydrophilic with water contact angles lower than 10° after prolonged irradiation under both visible and UV light. The evolution rate of the wetting angle and its dependence on the light characteristics are related to the nanostructure and the presence of silver embedded within the ZnO NRs. ÂEuropean Union NMP3-CT-2006- 032583Ministerio de Ciencia e Innovación MAT2010-21228, MAT2010-18447, CSD2008-00023Junta de Andalucía P09-TEP-5283, CTS-518

On the development of three new tools for organizing and sharing information in three-dimensional electron microscopy

This work was funded by the Spanish Ministerio de Economía y Competividad through grants BFU2009-09331, BIO2010-16566, ACI2009-1022, ACI2010-1088 and AIC-A- 2011-0638, by the Comunidad Autonoma de Madrid through grant S2010/BMD-2305, by NFS grant No. 1114901 and by the Spanish National Institute of Bioinformatics (a project funded by the Instituto de Salud Carlos III). This work was conducted using the Protégé resource, which is supported by grant LM007885 from the United States National Library of Medicine. COSS is a Ramón y Cajal researcher financed by the European Social Fund and the Ministerio de Economía y Competitividad. JV is a Juan de la Cierva Postdoctoral Fellow (JCI-2011-10185). This work was funded by Instruct, which is part of the European Strategy Forum on Research Infrastructures (ESFRI) and is supported by national member subscriptions

Leishmanicidal Activity of Nine Novel Flavonoids from Delphinium staphisagria

Objectives. To evaluate the in vitro leishmanicidal activity of nine flavonoid derivatives from Delphinium staphisagria against L. infantum and L. braziliensis. Design and Methods. The in vitro activity of compounds 1–9 was assayed on extracellular promastigote and axenic amastigote forms and on intracellular amastigote forms of the parasites. Infectivity and cytotoxicity tests were carried on J774.2 macrophage cells using Glucantime as the reference drug. The mechanisms of action were analysed performing metabolite excretion and transmission electronic microscope ultrastructural alteration studies. Results. Nine flavonoids showed leishmanicidal activity against promastigote as well as amastigote forms of Leishmania infantum and L. braziliensis. These compounds were nontoxic to mammalian cells and were effective at similar concentrations up to or lower than that of the reference drug (Glucantime). The results showed that 2″-acetylpetiolaroside (compound 8) was clearly the most active. Conclusion. This study has demonstrated that flavonoid derivatives are active against L. infantum and L. braziliensis

Sports, morality and body: the voices of sportswomen under Franco's dictatorship

The aim of this research is to study sportswomen’s perceptions and experiences of women’s sport in Francoist Spain (1939–1975). The main objective is to analyse the social, moral and aesthetic elements that are present in the experience of these athletes. This study was carried out with an intentional sample of 24 women from Andalusia, Aragon, Asturias, Basque Country, Catalonia and Valencia. They were interviewed by a network of researchers from six universities. Outstanding results show the existence of social limitations to start sports practice (particularly in the post-war period); the importance of sport as a character-building aspect; sport’s remarkable influence on their body self-concept; and the incidence on sports of the mainstream moral discourse, which created a female model that even affected sports clothing. The main conclusion is that sportswomen in that period were pioneers and had to fight against most of society in order to develop their facet as athletes, as they would not follow the established model

Preliminary data on the ovarian histological structures observed in black hakes (M. polli and M. senegalensis) off Mauritania

The black hakes, Merluccius polli and M. senegalensis, are target species of a trawl Spanish fleet in Mauritanian waters. M. polli is a deep-water hake while M. senegalensis shows a shallower distribution. Both species are mixed in the landings, although the deeper hake totals a greater fraction (85%) of the catch due to the fishing strategy of the trawl fleet. The female gonads of both hakes were collected during an experimental survey carried out in the Mauritanian EEZ. Mature ovaries were examined from the start of the reproductive season in this area. Ovaries were processed by a standard histological technique. Histological characteristics of ovarian tissues and oocyte stages were studied by light microscopy. The ovaries of black hakes showed various stages of oocyte development from the small sized, chromatin nuclear and perinucleolar oocytes, and the medium sized, cortical alveoli and vitellogenic oocytes. This last stage presents yolk granules occupying the cytoplasm at different levels. In the case of M. senegalensis, the presence of large sized oocytes with early migration of the nucleus to the animal pole, as well as fusion of oil droplets indicate maturation and imminent spawning, thus, indicating an earlier spawning than M. polli. Furthermore, postovulatory follicles observed in M. senegalensis indicate a recent batch spawning episode. This result is concordant with the values of GSI obtained for both species in these waters. The reproductive period extends from October to Mars with a defined peak in December - January for females of both hakes, although the shallower species, M. senegalensis, shows an earlier spawning in this study. Atretic stages were observed, but their incidence was low because the sampling corresponds to the beginning of the spawning period. The species are multiple batch spawners as suggested by their oocyte size frequency distribution in the ovary. The present study is a first approach to ovarian histology of M. polli and M. senegalensis, and intended to provide basic knowledge for further detailed studies on the reproductive biology of these species, essential for an adequate assessment of this stock.Instituto Español de Oceanografía (IEO

Qualidade ambiental de solos e águas da Mina Fé: situação inicial e alternativas de recuperação

La actividad minera contribuye a diferentes impactos ambientales. Tras el cierre es esencial una evaluación holística del estado de los principales componentes del ecosistema y de sus riesgos medioambientales, a modo de establecer y gestionar un programa de rehabilitación sostenible y especifico a la situación ambiental existente. El objetivo de este trabajo fue evaluar la calidad química de los suelos y aguas de escorrentía de la mina de uranio, mina Fé (Saelices el Chico, España), con el fin de obtener un diagnóstico de la problemática ambiental existente y de las potenciales intervenciones de recuperación a aplicar. Los suelos localizados dentro del área minera y los suelos naturales de la zona adyacente fueron muestreados, analizados fisicoquímicamente y clasificados según la World Reference Base. Además, fueron recogidas muestras de aguas de escorrentía de las escombreras, para evaluación química y termodinámica, así como, en el período seco, eflorescencias de sales de la superficie de los materiales para análisis química y mineralógica. Los suelos naturales (clasificados como Leptosoles líticos, háplicos y esqueletales, Cambisoles lépticos y háplicos, Acrisoles plínticos y Fluvisoles háplicos y gleicos) presentan baja fertilidad (evaluada por la concentración de nutrientes y materia orgánica) y una fuerte tendencia erosiva lo que, junto con las condiciones climáticas de la zona, conllevan a un escaso desarrollo de la cobertura vegetal. Asimismo, estos suelos sólo se mantienen, de forma muy incipiente, en las áreas donde existe una cobertura vegetal permanente. La mayoría de los suelos de mina están desarrollados sobre diferentes mezclas de material de partida y residuos de mina ricos en sulfuros, clasificándose como Tecnosoles espólicos, sulfúricos o sálicos, dependiendo de sus propiedades y/o condiciones específicas. Estas mezclas de materiales disminuyen el efecto negativo de los materiales de escombrera, ya que las concentraciones totales de los elementos potencialmente tóxicos son similares (excepto para el Pb) a las determinadas en los suelos naturales. Sin embargo, estos suelos tienen elevado riesgo ambiental debido a la generación de drenajes hiperácidos (pH ≈ 2,8), hiperoxidantes (Eh ≈ 759 mV), hiperconductoras (CE ≈ 12,8 dS m-1) con altos contenidos en elementos potencialmente tóxicos (ej. Al, Fe y Mn) y sulfatos (22,9-33,9 g L-1). En el periodo seco, la ascensión por capilaridad de este drenaje contribuye a la formación de sales evaporíticas sobre los materiales las cuales fueron identificadas, principalmente, como sulfatos de Al y Mg (epsomita y halotricita). Estas fases sólidas son únicamente sumideros temporales de sulfato y metales, pues se redisuelven con las lluvias liberando nuevamente los elementos al medio. Además, la baja fertilidad y capacidad de cambio, acidez, pedregosidad y salinidad de los suelos de mina limitan la colonización natural y el desarrollo vegetativo. Teniendo en cuenta el riego ambiental y las características/condicionantes de los suelos de mina, el proceso de recuperación de la mina Fé debe enfocarse, principalmente, en la minimización de la oxidación de los sulfuros y mejora de la fertilidad para, consecuentemente, promover el establecimiento de una cobertura vegetal biodiversa y los procesos de edafogénesis y biogeoquímicosMining activity leads to several environmental impacts. After the closure, the realization of a holistic evaluation of the main ecosystem components and their environmental risks is essential in order to define and manage a sustainable rehabilitation program specific to the current environmental situation. The objective of this work was to evaluate the chemical quality of the soils and runoff waters of the uranium mine, Fé mine (Saelices el Chico, Spain), in order to establish a diagnosis of the existing environmental problems and potential recovery actions to apply. Soils located within the mining area and natural soils from adjacent areas were sampled, classified according to the World Reference Base and analysed for their physico-chemical properties. Moreover, runoff water samples were collected for chemical and thermodynamic evaluation as well as, in the dry period, salt efflorescences from surface materials for chemical and mineralogical analysis. The natural soils (classified as Lithic, Haplic and Skeletic Leptosols, Leptic and Haplic Cambisols, Plinthic Acrisols, and Haplic and Gleyic Fluvisols) have low fertility (evaluated by concentration of nutrients and organic matter) and a strong erosive tendency which, together with the climatic conditions of the area, lead to a poor vegetation cover development. These soils are very incipient and are only located in areas where there is a permanent vegetation cover. Most of the mine soils are developed on different mixtures of host rock and sulfide-rich wastes, being classified as Sulfidic or Salic Spolic Technosols, depending on their specific properties and/or conditions. These mixtures of materials diminish the negative effect of the mine wastes, since the total concentrations of potentially toxic elements are similar (except for Pb) between mine and natural soils. However, these mine soils present a high environmental risk due to the generation of leachates with hyper-acid (pH ≈ 2.8), hyper-oxidant (Eh ≈ 759 mV) and hyper-conductor (EC ≈ 12.8 dS m-1) characteristics and with potentially high toxic elements (e.g. Al, Fe and Mn) and sulfates (22.9-33.9 g L-1). In the dry period, the ascension of the soil solution rich in elements contributes to the formation of evaporitic salts on the materials which were mainly identified as Al and Mg sulfates (epsomite and halotrichite). These solid phases are only temporary sinks of sulfate and metals, since they are re-dissolved with rain, releasing the elements to the environment. Moreover, the low fertility and cation exchange capacity, high acidity, stoniness and salinity of the mine soils limit the natural colonization and vegetative development. Considering the environmental risk and characteristics/conditions of the mine soils, the recovery process of the Fé mine should focus, mainly, on the sulfide oxidation minimization and fertility improvement in order to promote the establishment of a biodiverse plant cover as well as pedogenetic and biogeochemical processesA atividade mineira gera diferentes impactos ambientais. Após o fecho da mina, é essencial fazer uma avaliação holística do estado dos principais componentes do ecossistema e dos seus riscos ambientais de modo a estabelecer e gerir um programa de reabilitação sustentável e específico para a situação ambiental existente. O objetivo deste trabalho foi avaliar a qualidade química dos solos e águas de escorrência da mina de urânio, mina Fé (Saelices el Chico, Espanha) com o fim de obter um diagnóstico da problemática ambiental existente e das potenciais intervenções de recuperação a aplicar. Os solos localizados dentro da área mineira e os solos naturais da zona adjacente foram analisados relativamente às propriedades físicoquímicas e classificados segundo a World Reference Base. Além disso, foram colhidas amostras de águas de escorrência das escombreiras para avaliação química e termodinâmica, bem como, em período seco, eflorescências de sais da superfície dos materiais para análise química e mineralógica. Os solos naturais (classificados como Leptossolos Líticos, Háplicos e Esqueléticos, Cambissolos Lépticos e Háplicos, Acrissolos Plínticos e Fluvissolos Háplicos e Gleicos) apresentam baixa fertilidade (avaliada pela concentração de nutrientes e matéria orgânica) e uma forte tendência para sofrer erosão, o que conjuntamente com as condições climáticas da zona contribuem para um escasso desenvolvimento da cobertura vegetal. Estes solos são muito incipientes e estão apenas localizados em áreas onde há uma cobertura vegetal permanente. A maioria dos solos de mina desenvolveram-se em diferentes misturas de rochas encaixantes e resíduos mineiros ricos em sulfuretos, classificando-se como Tecnossolos Espólicos, Sulfúricos ou Sálicos, dependendo das suas propriedades e/ou condições específicas. Estas misturas diminuem o efeito negativo dos materiais de escombreira pois as concentrações totais dos elementos potencialmente tóxicos são semelhantes (exceto para o Pb) às determinadas nos solos naturais. Contudo, estes solos de mina apresentam um elevado risco ambiental devido à geração de lixiviados com características de pH hiperácido (pH ≈ 2,8) hiperoxidante (Eh ≈ 759 mV) e hipercondutor (EC ≈ 12,8 dS m-1) e com altos teores de elementos potencialmente tóxicos (por ex. Al, Fe e Mn) e sulfatos (22,9-33,9 g L-1). No período seco, a ascensão por capilaridade destas soluções ricas em elementos contribui para a formação de sais evaporíticos sobre os materiais de escombreira, os quais foram principalmente identificados como sulfatos de Al e Mg (epsomite e halotrichite). Estas fases sólidas são sumidouros temporários de sulfato e metais porque são redissolvidas pela água da chuva, libertando os elementos para o ambiente. Além disso, a baixa fertilidade e capacidade de troca catiónica, acidez, pedregosidade e salinidade dos solos de mina limitam a colonização natural e o desenvolvimento vegetativo. Tendo em conta o risco ambiental e as características/condicionantes dos solos de mina, o processo de recuperação da mina Fé deve focar-se, principalmente, na minimização da oxidação dos sulfuretos e na melhoria da fertilidade dos solos para promover o estabelecimento de uma cobertura vegetal biodiversa e os processos pedogenéticos e biogeoquímicosLos autores agradecen a la Xunta de Galicia por el apoyo financiero del Grupo AMBIOSOL (GRC2014/003)S

In vitro and in vivo studies of the trypanocidal activity of four terpenoid derivatives against Trypanosoma cruzi.

Four terpenoid derivatives were examined for their activity against Trypanosoma cruzi. Our results show that two compounds were very active in vitro against both extra- and intracellular forms. These compounds, non-toxic for the host cells, are more effective than the reference drug benznidazole. The capacity to infect cells was negatively affected and the number of amastigotes and trypomastigotes was reduced. A wide range of ultrastructural alterations was found in the epimastigote forms treated with these compounds. Some metabolic changes occurred presumably at the level of succinate and acetate production, perhaps caused by the disturbance of the enzymes involved in sugar metabolism inside the mitochondria. In vivo results were consistent with those observed in vitro. The parasitic load was significantly lower than in the control assay with benznidazole. The effects of these products showed the reduction of the anti-T. cruzi antibodies level during the chronic stage