117 research outputs found

    High performance novel gadolinium doped ceria/yttria stabilized zirconia/nickel layered and hybrid thin film anodes for application in solid oxide fuel cells

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    Magnetron sputtering under oblique angle deposition was used to produce Ni-containing ultra thin film anodes comprising alternating layers of gadolinium doped ceria (GDC) and yttria stabilized zirconia (YSZ) of either 200 nm or 1000 nm thickness. The evolution of film structure from initial deposition, through calcination and final reduction was examined by XRD, SEM, TEM and TOF-SIMS. After subsequent fuel cell usage, the porous columnar architecture of the two-component layered thin film anodes was maintained and their resistance to delamination from the underlying YSZ electrolyte was superior to that of corresponding single component Ni-YSZ and Ni-GDC thin films. Moreover, the fuel cell performance of the 200 nm layered an- odes compared favorably with conventional commercially available thick anodes. The observed dependence of fuel cell performance on individual layer thicknesses prompted study of equivalent but more easily fabricated hybrid anodes consisting of simultaneously deposited Ni-GDC and Ni-YSZ, which procedure resulted in exceptionally intimate mixing and interaction of the components. The hybrids exhibited very unusual and favorable I---V characteristics, along with exceptionally high power densities at high currents. Their discovery is the principal contribution of the present work.European Union's Seventh Framework Programme FP7/2007–2013Fuel Cells and Hydrogen Joint Technology Initiative under the T-CELL project, grant 298300MINECO (Spain), grants nº MAT2013-40852RJuan de la Cierva Programme FPDI-2013-1862

    Protección de la Heparina a las células B- pancreáticas frente a radicales libres de Oxígeno.

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    La diabetes autoinmune tipo 1 se caracteriza por la invasión de células mononucleares en los islotes pancreáticos, destruyendo así las células beta productoras de insulina. Se ha visto que in vivo la destrucción autoinmune de los islotes se asocia con la producción de heparanasa, la cual degrada heparán sulfato (molécula imprescindible para la supervivencia de los islotes) y se permite la entrada de las células inmunitarias que atacarán los islotes beta pancreáticos. Se han obtenido resultados mediante la adición de concentraciones conocidas de heparina, la cual confiere una protección extra frente a radicales libres de oxígeno y como consecuencia hay una disminución de la mortalidad celular.A través de tres líneas celulares distintas se ha llevado a cabo el experimento. Primeramente con Rinm5F productora de insulina y somatostatina, con células Ins capaces de responder al estímulo de glucosa produciendo y secretando insulina y finalmente con fibroblastos. El experimento se basa en dejar crecer las cepas celulares en un número determinado de flacs según el tratamiento. Se añade heparina a una concentración conocida y establecida anteriormente y al día siguiente con una concentración exacta de agua oxigenada (aporta los radicales libres de oxígeno) se la añadimos al cultivo. Recogemos las células y gracias al ioduro de propidio con concentración 1 mg/ml marcamos las células muertas para así poder comprobar el porcentaje de supervivencia celular que le ha conferido la heparina a cada línea celular. Procedemos a realizar el contaje con el citómetro que indica el % de muerte celular, ya que el ioduro de propidio es un agente intercalante que se une a los ácidos nucleicos. Esta molécula fluorescente se utiliza para evaluar la viabilidad celular o el contenido de ADN en las células. Se puede utilizar para diferenciar células necróticas, apoptóticas o vivas.Los resultados obtenidos con las líneas celulares Rinm5F y las Ins nos muestran que a bajas concentraciones de agua oxigenada y con heparina, efectivamente hay protección ya que la muerte celular se reduce de un 10 a un 15%. En cambio con los fibroblastos no vemos protección a ninguna de las concentraciones establecidas, resultado que ya esperábamos en nuestra hipótesis inicial. Estos resultados sólo son el inicio de un largo estudio, ya que  primero se ajustan las concentraciones a trabajar con radicales libres de oxígeno, pero en un  futuro el estudio se realizará también con radicales de nitrógeno

    Relación entre muerte celular y mantenimiento de la pluripotencialidad de células mES en protocolos de diferenciación con óxido nítrico

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    En este proyecto se pretende estudiar la relación entre la muerte celular y la diferenciación durante el desarrollo usando como modelo experimental células madre embrionarias de ratón (mESC). Se ha descrito que las altas concentraciones de DETA-NO (500uM) provocan la diferenciación de estas mESC hacia endodermo (Mora-Castilla et al., 2010), pero en estos protocolos no todas consiguen sobrevivir y un alto porcentaje de células muere. Es por ello que se quiere analizar la relación entre ambos eventos. Se estudiará, por un lado, si el bloqueo de la apoptosis con inhibidores de caspasas tiene efectos sobre la diferenciación; y por otro lado si es probable que exista una liberación de moléculas al medio por parte de las células apoptóticas que contribuya a la pérdida de la pluripotencialidad de sus vecinas. Para ello se ha analizado el mantenimiento del estado pluripotente en dos tipos de ensayos. Por un lado se ha estudiado el efecto de inhibidores de caspasas en tratamientos con DETA-NO en dos líneas de mESC (D3 y R1/E), y por otro lado se ha evaluado el efecto del reciclaje de medios de cultivo en la línea celular D3. Para medir el mantenimiento de la pluripotencialidad se han empleado distintas técnicas de biología molecular (extracción de RNA, PCR, qPCR, Western Blotting…) y técnicas de microscopía. Con ello se han buscado diferencias de expresión de los marcadores de pluripotencia (Nanog y Oct4) y marcadores de endodermo (Pdx1, Cxcr4), mesodermo (Brachyury) y ectodermo (Zic1). Se ha demostrado que el uso de inhibidores de caspasas en tratamientos con DETA-NO bloquea la regulación a la baja de Nanog, tanto en niveles de RNAm como de proteína, y disminuye la expresión de los marcadores de diferenciación. Por otro lado, el uso de medios de cultivo reciclados procedentes de tratamientos anteriores con y sin DETA-NO, suplementados y con el factor inhibidor de la diferenciación LIF (Leukemia Inhibitory Factor) estimula la diferenciación de las células. Los resultados obtenidos apuntan a que podría existir una relación entre la muerte celular y la diferenciación, ya que al inhibir la muerte por apoptosis se favorece el mantenimiento del estado pluripotente . Además, el uso de medios reciclados ayuda a la diferenciación de las células incluso en presencia de LIF. Por ello se cree que células apoptóticas podrían estar secretando sustancias al medio que las células vecinas estarían utilizando como señales para diferenciarse

    Transcriptome sequencing of three Pseudo-nitzschia species reveals comparable gene sets and the presence of Nitric Oxide Synthase genes in diatoms

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    Diatoms are among the most diverse eukaryotic microorganisms on Earth, they are responsible for a large fraction of primary production in the oceans and can be found in different habitats. Pseudo-nitzschia are marine planktonic diatoms responsible for blooms in coastal and oceanic waters. We analyzed the transcriptome of three species, Pseudo-nitzschia arenysensis, Pseudo-nitzschia delicatissima and Pseudo-nitzschia multistriata, with different levels of genetic relatedness. These species have a worldwide distribution and the last one produces the neurotoxin domoic acid. We were able to annotate about 80% of the sequences in each transcriptome and the analysis of the relative functional annotations allowed comparison of the main metabolic pathways, pathways involved in the biosynthesis of isoprenoids (MAV and MEP pathways), and pathways putatively involved in domoic acid synthesis. The search for homologous transcripts among the target species and other congeneric species resulted in the discovery of a sequence annotated as Nitric Oxide Synthase (NOS), found uniquely in Pseudo-nitzschia multistriata. The predicted protein product contained all the domains of the canonical metazoan sequence. Putative NOS sequences were found in other available diatom datasets, supporting a role for nitric oxide as signaling molecule in this group of microalgae

    Genetic Ancestry, Race, and Severity of Acutely Decompensated Cirrhosis in Latin America

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    Background & Aims: Genetic ancestry or racial differences in health outcomes exist in diseases associated with systemic inflammation (eg, COVID-19). This study aimed to investigate the association of genetic ancestry and race with acute-on-chronic liver failure (ACLF), which is characterized by acute systemic inflammation, multi-organ failure, and high risk of short-term death. / Methods: This prospective cohort study analyzed a comprehensive set of data, including genetic ancestry and race among several others, in 1274 patients with acutely decompensated cirrhosis who were nonelectively admitted to 44 hospitals from 7 Latin American countries. / Results: Three hundred ninety-five patients (31.0%) had ACLF of any grade at enrollment. Patients with ACLF had a higher median percentage of Native American genetic ancestry and lower median percentage of European ancestry than patients without ACLF (22.6% vs 12.9% and 53.4% vs 59.6%, respectively). The median percentage of African genetic ancestry was low among patients with ACLF and among those without ACLF. In terms of race, a higher percentage of patients with ACLF than patients without ACLF were Native American and a lower percentage of patients with ACLF than patients without ACLF were European American or African American. In multivariable analyses that adjusted for differences in sociodemographic and clinical characteristics, the odds ratio for ACLF at enrollment was 1.08 (95% CI, 1.03–1.13) with Native American genetic ancestry and 2.57 (95% CI, 1.84–3.58) for Native American race vs European American race. / Conclusions: In a large cohort of Latin American patients with acutely decompensated cirrhosis, increasing percentages of Native American ancestry and Native American race were factors independently associated with ACLF at enrollment

    Bovine Tuberculosis in Doñana Biosphere Reserve: The Role of Wild Ungulates as Disease Reservoirs in the Last Iberian Lynx Strongholds

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    Doñana National Park (DNP) in southern Spain is a UNESCO Biosphere Reserve where commercial hunting and wildlife artificial feeding do not take place and traditional cattle husbandry still exists. Herein, we hypothesized that Mycobacterium bovis infection prevalence in wild ungulates will depend on host ecology and that variation in prevalence will reflect variation in the interaction between hosts and environmental risk factors. Cattle bTB reactor rates increased in DNP despite compulsory testing and culling of infected animals. In this study, 124 European wild boar, 95 red deer, and 97 fallow deer were sampled from April 2006 to April 2007 and analyzed for M. bovis infection. Modelling and GIS were used to identify risk factors and intra and inter-species relationships. Infection with M. bovis was confirmed in 65 (52.4%) wild boar, 26 (27.4%) red deer and 18 (18.5%) fallow deer. In the absence of cattle, wild boar M. bovis prevalence reached 92.3% in the northern third of DNP. Wild boar showed more than twice prevalence than that in deer (p<0.001). Modelling revealed that M. bovis prevalence decreased from North to South in wild boar (p<0.001) and red deer (p<0.01), whereas no spatial pattern was evidenced for fallow deer. Infection risk in wild boar was dependent on wild boar M. bovis prevalence in the buffer area containing interacting individuals (p<0.01). The prevalence recorded in this study is among the highest reported in wildlife. Remarkably, this high prevalence occurs in the absence of wildlife artificial feeding, suggesting that a feeding ban alone would have a limited effect on wildlife M. bovis prevalence. In DNP, M. bovis transmission may occur predominantly at the intra-species level due to ecological, behavioural and epidemiological factors. The results of this study allow inferring conclusions on epidemiological bTB risk factors in Mediterranean habitats that are not managed for hunting purposes. Our results support the need to consider wildlife species for the control of bTB in cattle and strongly suggest that bTB may affect animal welfare and conservation

    The management of acute venous thromboembolism in clinical practice. Results from the European PREFER in VTE Registry

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    Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in Europe. Data from real-world registries are necessary, as clinical trials do not represent the full spectrum of VTE patients seen in clinical practice. We aimed to document the epidemiology, management and outcomes of VTE using data from a large, observational database. PREFER in VTE was an international, non-interventional disease registry conducted between January 2013 and July 2015 in primary and secondary care across seven European countries. Consecutive patients with acute VTE were documented and followed up over 12 months. PREFER in VTE included 3,455 patients with a mean age of 60.8 ± 17.0 years. Overall, 53.0 % were male. The majority of patients were assessed in the hospital setting as inpatients or outpatients (78.5 %). The diagnosis was deep-vein thrombosis (DVT) in 59.5 % and pulmonary embolism (PE) in 40.5 %. The most common comorbidities were the various types of cardiovascular disease (excluding hypertension; 45.5 %), hypertension (42.3 %) and dyslipidaemia (21.1 %). Following the index VTE, a large proportion of patients received initial therapy with heparin (73.2 %), almost half received a vitamin K antagonist (48.7 %) and nearly a quarter received a DOAC (24.5 %). Almost a quarter of all presentations were for recurrent VTE, with &gt;80 % of previous episodes having occurred more than 12 months prior to baseline. In conclusion, PREFER in VTE has provided contemporary insights into VTE patients and their real-world management, including their baseline characteristics, risk factors, disease history, symptoms and signs, initial therapy and outcomes
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