269 research outputs found

    Methanogenesis at high temperature, high ionic strength and low pH in the volcanic area of Dallol, Ethiopia

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    The Dallol geothermal area originated as a result of seismic activity and the presence of a shallow underground volcano, both due to the divergence of two tectonic plates. In its ascent, hot water dissolves and drags away the subsurface salts. The temperature of the water that comes out of the chimneys is higher than 100C, with a pH close to zero and high mineral concentration. These factors make Dallol a polyextreme environment. So far, nanohaloarchaeas, present in the salts that form the walls of the chimneys, have been the only living beings reported in this extreme environment. Through the use of complementary techniques: culture in microcosms, methane stable isotope signature and hybridization with specific probes, the methanogenic activity in the Dallol area has been assessed. Methane production in microcosms, positive hybridization with the Methanosarcinales probe and the δC-values measured, show the existence of extensive methanogenic activity in the hydrogeothermic Dallol system. A methylotrophic pathway, carried out by Methanohalobium and Methanosarcina-like genera, could be the dominant pathway for methane production in this environment.Agencia Estatal de Investigación (AEI), grant MDM-2017-0737 (Unidad de Excelencia “María de Maeztu”-Centro de Astrobiología INTA-CSIC) and the Spanish Ministerio de Ciencia e Innovación (MICINN

    Persistence of instanton connections in chemical reactions with time dependent rates

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    The evolution of a system of chemical reactions can be studied, in the eikonal approximation, by means of a Hamiltonian dynamical system. The fixed points of this dynamical system represent the different states in which the chemical system can be found, and the connections among them represent instantons or optimal paths linking these states. We study the relation between the phase portrait of the Hamiltonian system representing a set of chemical reactions with constant rates and the corresponding system when these rates vary in time. We show that the topology of the phase space is robust for small time-dependent perturbations in concrete examples and state general results when possible. This robustness allows us to apply some of the conclusions on the qualitative behavior of the autonomous system to the time-dependent situation

    Metodología de investigación de Rocas Ornamentales: Granitos.

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    Durante la realización del proyecto del IGME ·Potencial Básico de Granitos y Neises Ornamentales en Castilla y León se desarrolló una metodología sistemática de investigación de granitos para uso ornamental que, por su versatilidad, puede hacerse extensible, en sus aspectos más generales, a otros tipos de rocas ornamentales e, incluso, rocas industriales en general. Para ello, se desarrollan una serle de fases de trabajo que comprenden: recogida de información, exploración de campo a escalas 1 :50.000, 1 :25.000 y 1: 10.000, valoración de áreas y elección de puntos canterables, todo ello mediante la cuantificación de todos los parámetros y valores que han de tenerse en cuenta en la investigación de rocas ornamentales, que nos permiten dar un tratamiento objetivo a todas las áreas estudiadas

    Semillas de chia oscuras y blancas cultivadas orgánicamente vs convencionalmente (Salvia hispanica L.): composición de ácidos grasos, actividad antioxidante y propiedades tecno-funcionales

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    The effects of organic and conventional crop systems on chemical composition, antioxidant activity and functional properties were evaluated in white and dark chia (Salvia hispanica L.) seeds. The organic system reduced the total protein content, and increased the total carbohydrates but did not change polyunsaturated fatty acids, total phenolic or flavonoids. Organic white chia seeds showed the best techno-functional properties. The antioxidant capacity of chia extracts varied in relation to the chemical complexity and differential rate kinetics of different assays. Extractable total phenolic acids and antioxidant capacity were better in organic white chia seeds. In this first approach, we have demonstrated that the organic white chia seed has a better total antioxidant capacity measured by direct quencher approaches than its conventionally-grown counterpart. To summarize, we conclude that the organic white chia seed could be a dietary source of antioxidants with a potential to promote health benefits in systemic functions and/or microbiota and the use of its techno-functional properties for the food industry.El efecto de los sistemas de cultivo orgánico vs convencional sobre la composición química, la actividad antioxidante y las propiedades funcionales fueron evaluadas en semillas de chía blanca y oscura (Salvia hispanica L.). El sistema orgánico redujo el contenido total de proteína, aumentó los carbohidratos totales, pero no modificó los ácidos grasos poliinsaturados, fenólicos totales y flavonoides. Las semillas orgánicas de chía blanca mostraron las mejores propiedades tecno-funcionales. La capacidad antioxidante de los extractos de chía varió en relación con la complejidad química y la cinética de velocidad diferencial de los diferentes ensayos. Los ácidos fenólicos totales y la capacidad antioxidante fueron mejores en las semillas orgánicas de chía blanca. En este primer enfoque, hemos demostrado que la semilla orgánica de chía blanca tiene una mejor capacidad antioxidante total medida por métodos directos que su contraparte cultivada convencionalmente. En resumen, indicamos que las semillas orgánicas de chía blanca podría ser una fuente dietética de antioxidantes con potencial para promover beneficios saludables en la función sistémica y/o microbiota y el uso de la propiedades tecno-funcionales para la industria alimentaria

    Mouse p53-deficient cancer models as platforms for obtaining genomic predictors of human cancer clinical outcomes

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    Mutations in the TP53 gene are very common in human cancers, and are associated with poor clinical outcome. Transgenic mouse models lacking the Trp53 gene or that express mutant Trp53 transgenes produce tumours with malignant features in many organs. We previously showed the transcriptome of a p53-deficient mouse skin carcinoma model to be similar to those of human cancers with TP53 mutations and associated with poor clinical outcomes. This report shows that much of the 682-gene signature of this murine skin carcinoma transcriptome is also present in breast and lung cancer mouse models in which p53 is inhibited. Further, we report validated gene-expression-based tests for predicting the clinical outcome of human breast and lung adenocarcinoma. It was found that human patients with cancer could be stratified based on the similarity of their transcriptome with the mouse skin carcinoma 682-gene signature. The results also provide new targets for the treatment of p53-defective tumours

    Results of salt intake restriction monitored with the new sodium control biosensor

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    Adherence to a low sodium (Na) diet is crucial in patients under hemodialysis, as it improves cardiovascular outcomes and reduces thirst and interdialytic weight gain. Recommended salt intake is lower than 5 g/day. The new 6008 CareSystem monitors incorporate a Na module that offers the advantage of estimating patients' salt intake. The objective of this study was to evaluate the effect of dietary Na restriction for 1 week, monitored with the Na biosensor.A prospective study was conducted in 48 patients who maintained their usual dialysis parameters and were dialyzed with a 6008 CareSystem monitor with activation of the Na module. Total Na balance, pre/postdialysis weight, serum Na (sNa), changes in pre- to post-dialysis sNa (ΔsNa), diffusive balance, and systolic and diastolic blood pressure were compared twice, once after 1 week of patients' usual Na diet and again after another week with more restricted Na intake.Restricted Na intake increased the percentage of patients on a low-sodium diet (<85 Na mmol/day) from 8% to 44%. Average daily Na intake decreased from 149 ± 54 to 95 ± 49 mmol and interdialytic weight gain was reduced by 460 ± 484 g per session. More restricted Na intake also decreased pre-dialysis sNa and increased both intradialytic diffusive balance and ΔsNa. In hypertensive patients, reducing daily sodium by more than 3 g Na/day lowered their systolic blood pressure.The new Na module allowed objective monitoring of Na intake, which in turn could permit more precise personalized dietary recommendations in patients under hemodialysis.S. Karger AG, Basel

    Demografía y crecimiento primario durante la regeneración de tres especies de pino a lo largo de gradientes climáticos

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    13 páginas, 4 figuras y 3 tablasLa regeneración es un proceso crítico en la dinámica de los bosques, que presenta una marcada heterogeneidad temporal y espacial. En este trabajo se pretende avanzar en el conocimiento de las variables bióticas y abióticas que determinan a escala local la presencia, abundancia y crecimiento primario de plántulas de tres especies de pino: Pinus sylvestris, P. nigra y P. uncinata, y determinar el efecto relativo del clima. Para ello se muestrearon 216 parcelas distribuidas a lo largo de gradientes climáticos en siete localidades montañosas. Se censaron las plántulas recién emergidas y el resto de juveniles, y se midieron los crecimientos anuales. Los resultados mostraron diferencias significativas entre especies con efectos directos e indirectos del clima sobre la demografía y el estado de los juveniles. En las tres especies se apreció que la supervivencia de los juveniles aparecía desplazada hacia altitudes mayores respecto donde se producía el óptimo de la emergencia. Las relaciones locales de competencia y facilitación ejercieron efectos importantes sobre la regeneración de las tres especies, siendo éstos modulados por el clima.Ministerio Español de Innovación y Ciencia Consolider-Montes (CSD2008_00040), Los autores agradecen a toda la gente que hizo posible el trabajo de campo: R. Freire, B. Santamaría, J. Martínez, D. López, R. Ruíz-Puche, E. Molina, L. Ivorra, S. Martín, B. Ros y C. Boubekeur. También el apoyo estadístico de R. Manson.Proyecto europeo BACCARA (CE: FP7-226299, 7FP)Peer reviewe

    Магнитные свойства металлоуглеродных комплексов C–Ni

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    Новый метод металлизации графита кластерами металлических атомов применен для получения металлоуглеродных нанокомплексов С–Ni. Измерения магнитных свойств образцов обнаруживают сильно неравновесное поведение намагниченности в случаях охлаждения в магнитном поле и без него. Для объяснения поведения магнитных свойств нанокомплексов использована модель суперпарамагнитных частиц. В рамках этой модели определена величина анизотропии и оценен характерный размер наночастиц.Новий метод металізації графіту кластерами металевих атомів застосовано для отримання металовуглецевих нанокомплексів C–Ni. Вимірювання магнітних властивостей зразків виявляє сильно нерівноважну поведінку намагніченості у випадках охолодження в магнітному полі та без нього. Для пояснення поведінки магнітних властивостей нанокомплексів використано модель суперпарамагнітних частинок. В рамках цієї моделі визначено величину анізотропії та оцінено характерний розмір наночастинок.A new method of graphite metallization by clusters of metallic atoms is used to produce carbon-metal C-Ni nanocomplexes. Measurements of the magnetic properties of the samples reveal a highly non-equilibrium behavior of magnetization in cases of cooling in a magnetic field and without. The superparamagnetic particle model is used to explain the behavior of the magnetic properties of the nanocomplexes. The anisotropy is determined and the size of the nanoparticles is estimated based on this model

    Molecular method for the characterization of Coxiella burnetii from clinical and environmental samples: variability of genotypes in Spain

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    BACKGROUND: Coxiella burnetii is a highly clonal microorganism which is difficult to culture, requiring BSL3 conditions for its propagation. This leads to a scarce availability of isolates worldwide. On the other hand, published methods of characterization have delineated up to 8 different genomic groups and 36 genotypes. However, all these methodologies, with the exception of one that exhibited limited discriminatory power (3 genotypes), rely on performing between 10 and 20 PCR amplifications or sequencing long fragments of DNA, which make their direct application to clinical samples impracticable and leads to a scarce accessibility of data on the circulation of C. burnetii genotypes. RESULTS: To assess the variability of this organism in Spain, we have developed a novel method that consists of a multiplex (8 targets) PCR and hybridization with specific probes that reproduce the previous classification of this organism into 8 genomic groups, and up to 16 genotypes. It allows for a direct characterization from clinical and environmental samples in a single run, which will help in the study of the different genotypes circulating in wild and domestic cycles as well as from sporadic human cases and outbreaks. The method has been validated with reference isolates. A high variability of C. burnetii has been found in Spain among 90 samples tested, detecting 10 different genotypes, being those adaA negative associated with acute Q fever cases presenting as fever of intermediate duration with liver involvement and with chronic cases. Genotypes infecting humans are also found in sheep, goats, rats, wild boar and ticks, and the only genotype found in cattle has never been found among our clinical samples. CONCLUSIONS: This newly developed methodology has permitted to demonstrate that C. burnetii is highly variable in Spain. With the data presented here, cattle seem not to participate in the transmission of C. burnetii to humans in the samples studied, while sheep, goats, wild boar, rats and ticks share genotypes with the human population

    Exploring Recollection and Familiarity Impairments in Parkinson´s disease

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    There is conflicting evidence on whether patients diagnosed with Parkinson's disease (PD) have cognitive deficits associated with episodic memory and particularly with recognition memory. The aim of the present study was to explore whether PD patients exhibit deficits in recollection and familiarity, the two processes involved in recognition. A sample of young healthy participants (22) was tested to verify that the experimental tasks were useful estimators of recognition processes. Two further samples ¿ one of elderly controls (16) and one of PD patients (20) ¿ were the main focus of this research. All participants were exposed to an associative recognition task aimed at estimating recollection followed by a two-alternative forced-choice (2AFC) test designed to estimate familiarity. The analyses showed a deficit in associative recognition in PD patients and no difference between elderly controls and PD patients in the 2AFC test. By contrast, young healthy participants were better than elderly controls and PD patients in both components of recognition. Further analyses of results of the 2AFC test indicated that the measure chosen to estimate conceptual familiarity was adequate
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