2,833 research outputs found

    The multiple contributions of thyroid hormone to heat production

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    Evaluating wild grapevine tolerance to copper toxicity

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    We evaluate copper tolerance and accumulation in Vitis vinifera ssp. sylvestris in populations from a copper contaminated site and an uncontaminated site, and in the grapevine rootstock "41B", investigating the effects of copper (0-23. mM) on growth, photosynthetic performance and mineral nutrient content. The highest Cu treatment induced nutrient imbalances and inhibited photosynthetic function, causing a drastic reduction in growth in the three study plants. Effective concentration was higher than 23. mM Cu in the wild grapevines and around 9. mM in the "41B" plants. The wild grapevine accessions studied controlled root Cu concentration more efficiently than is the case with the "41B" rootstock and must be considered Cu-tolerant. Wild grapevines from the Cu-contaminated site present certain physiological characteristics that make them relatively more suitable for exploitation in the genetic improvement of vines against conditions of excess Cu, compared to wild grapevine populations from uncontaminated site

    Enzymatic dyeing of keratinous materials

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    Poster apresentado no "Biotrans Olomouc 2003 - 6th International Symposium on Biocatalysis and Biotransformations", em Olomouc, Czech Republic, 2003This study reports on the dyeing of keratinous materials using appropriate enzymatic systems – laccases and protein disulfide isomerase. The enzymatic dyeing was performed as a batchwise process at the temperature and pH of maximum enzyme activity. Laccases generate the colour “in situ” starting from low molecular colourless compounds – dye precursor and dye modifiers. Different hues and depth of shades could be achieved varying the concentration of the modifiers and the time of laccase treatment. Protein disulfide isomerases, based on their ability to catalyze thiol-disufide exchange, including oxidation, reduction and rearrangement, were used for covalent fixation of novel cysteine-modified dyes on keratinous fibres

    Identificación de Leishmania infantum en Puerto Iguazú, Misiones, Argentina

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    The emergence of zoonotic visceral leishmaniasis (ZVL) in Latin America is a growing public health problem. The urbanization of ZVL has been observed in different countries around the world, and there are a growing number of reports drawing attention to the emergence of this infection in new locations, as well as its increase in previously established areas of endemicity. In the city of Posadas, Misiones province, Northeastern Argentina, the transmission of ZVL associated with canines and Lutzomyia longipalpis was first reported in 2006. In the city of Puerto Iguazú, also in Misiones province, the first human case of ZVL was reported in February 2014. From 209 surveyed dogs, 15 (7.17%) were identified as positive by serological and/or parasitological methods. Amplification was observed in 14 samples and in all cases the species implicated was Leishmania infantum. To the authors’ knowledge, this is the first molecular characterization of L. infantum from dogs in this area.La emergencia de leishmaniosis visceral zoonótica (LVZ) en América Latina es problema de salud pública en aumento. La urbanización de la LVZ es un fenómeno observado en diferentes países alrededor del mundo y hay un número creciente tanto de denuncias respecto a la aparición de esta infección en nuevas ubicaciones, como su aumento en zonas endémicas previamente establecidas. En la ciudad de Posadas, provincia de Misiones, nordeste de Argentina, la transmisión de LVZ asociada a canes y Lutzomyia longipalpis fue descrita por primera vez en 2006. En la ciudad de Puerto Iguazú, provincia de Misiones, el primer caso humano de LVZ tuvo lugar en febrero de 2014. De 209 perros muestreados, 15 (7.17%) resultaron positivos mediante métodos serológicos y/o parasitológicos. Se observó amplificación en 14 muestras y en todos los casos la especie implicada fue Leishmania infantum. Según nuestro conocimiento, esta es la primera caracterización molecular de L. infantum en perros procedentes de este área

    La evaluación de la calidad de enseñanza universitaria mediante la percepción del alumno de una actividad práctica: propuesta de escalas de medida

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    El panorama universitario actual, centrado en la valoración y juicio de los distintos agentes del proceso de enseñanza-aprendizaje, supone un campo adecuado para el desarrollo de investigaciones que pretendan alcanzar indicadores fiables del desempeño de las labores docentes. La futura implantación del Espacio Europeo de Educación Superior (EEES), acrecienta el interés por este tipo de investigaciones.Este trabajo, centrado en este contexto, pretende evaluar y valorar, por parte del discente, una actividad práctica constitutiva del programa de dos asignaturas universitarias impartidas en dos licenciaturas oficiales. Para su evaluación desarrollaremos una escala de medida que permita conocer la percepción de calidad de dicha actividad por parte de los alumnos y las posibles fuentes de mejora. Con los resultados obtenidos podremos conocer que aportación tiene esta práctica en el proceso de aprendizaje de esta materia y para la formación general del alumno

    Biobased films of nanocellulose and mango leaf extract for active food packaging: supercritical impregnation versus solvent casting

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    Antioxidant and antimicrobial free-standing films composed of nanofibrillated cellulose (NFC) and a polyphenolic-rich extract, viz. mango leaf extract (MLE), were produced via supercritical solvent impregnation (SSI) and conventional solvent casting film-processing methodologies. The CO2-assisted impregnation of NFC with MLE created robust films with thermal stability up to 250 °C, good mechanical performance (Young's modulus > 4.7 GPa), UV-light barrier properties, antioxidant capacity with maximum inhibition percentage of ca. 84%, and antimicrobial activity against Staphylococcus aureus (growth inhibition ≈ 37%) and Escherichia coli (growth inhibition ≈ 91%). The comparison of the NFC/MLE films prepared by SSI with those fabricated via solvent casting shows a clear advantage of the SSI methodology. Particularly, the antioxidant and antimicrobial activities are visibly higher in the films fabricated by the CO2-assisted impregnation of MLE into NFC. In fact, for the SSI films, the MLE components are mostly adsorbed at the surface and not in the bulk of the biopolymeric matrix, which translates into faster migrations and, hence, higher active properties. All these findings evinced the potential performance of the NFC/MLE films prepared by the eco-friendly SSI as UV-blocking, antioxidant, and antimicrobial bio-based materials for application as sustainable active food packaging.publishe

    Spontaneous vesicle formation in catanionic mixtures of amino acid-based surfactants: Chain length symmetry effects

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    The use of amino acids for the synthesis of novel surfactants with vesicle-forming properties potentially enhances the biocompatibility levels needed for a viable alternative to conventional lipid vesicles. In this work, the formation and characterization of catanionic vesicles by newly synthesized lysine- and serine-derived surfactants have been investigated by means of phase behavior mapping and PFG-NMR diffusometry and cryo-TEM methods. The lysine-derived surfactants are double-chained anionic molecules bearing a pseudogemini configuration, whereas the serine-derived amphiphile is cationic and single-chained. Vesicles form in the cationic-rich side for narrow mixing ratios of the two amphiphiles. Two pairs of systems were studied: one symmetric with equal chain lengths, 2C(12)/C(12), and the other highly asymmetric with 2C(8)/C(16) chains, where the serine-based surfactant has the longest chain. Different mechanisms of the vesicle-to-micelle transition were found, depending on symmetry: the 2C12/C12 system entails limited micellar growth and intermediate phase separation, whereas the 2C(8)/C(16) system shows a continuous transition involving large wormlike micelles. The results are interpreted on the basis of currently available models for the micelle-vesicle transitions and the stabilization of catanionic vesicles (energy of curvature vs mixing entropy)

    CosmoHub: Interactive exploration and distribution of astronomical data on Hadoop

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    We present CosmoHub (https://cosmohub.pic.es), a web application based on Hadoop to perform interactive exploration and distribution of massive cosmological datasets. Recent Cosmology seeks to unveil the nature of both dark matter and dark energy mapping the large-scale structure of the Universe, through the analysis of massive amounts of astronomical data, progressively increasing during the last (and future) decades with the digitization and automation of the experimental techniques. CosmoHub, hosted and developed at the Port d'Informació Científica (PIC), provides support to a worldwide community of scientists, without requiring the end user to know any Structured Query Language (SQL). It is serving data of several large international collaborations such as the Euclid space mission, the Dark Energy Survey (DES), the Physics of the Accelerating Universe Survey (PAUS) and the Marenostrum Institut de Ciències de l'Espai (MICE) numerical simulations. While originally developed as a PostgreSQL relational database web frontend, this work describes the current version of CosmoHub, built on top of Apache Hive, which facilitates scalable reading, writing and managing huge datasets. As CosmoHub's datasets are seldomly modified, Hive it is a better fit. Over 60 TiB of cataloged information and 50×10 astronomical objects can be interactively explored using an integrated visualization tool which includes 1D histogram and 2D heatmap plots. In our current implementation, online exploration of datasets of 10 objects can be done in a timescale of tens of seconds. Users can also download customized subsets of data in standard formats generated in few minutes.CosmoHub has been partially funded through projects of the Spanish national program “Programa Estatal de I + D + i” of the Spanish government. The support of the ERDF fund is gratefully acknowledged

    Primera caracterización molecular de Leishmania infantum en pacientes con leishmaniosis visceral de la Provincia de Misiones, Argentina

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    Introduction: Cutaneous leishmaniasis caused by L. braziliensis has been historically endemic in Argentina and several cases of visceral leishmaniasis following initial cutaneous leishmaniasis have been reported. Visceral leishmaniasis started to appear in Argentina in 2006 in the city of Posadas, Misiones province, affecting both humans and dogs.Objective: To identify the etiologic agent to species level in patients with visceral leishmaniasis diagnosis in Misiones province and describe its clinical and epidemiological characteristics.Materials and methods: A cohort of 24 patients from Misiones province was studied from 2009 to 2016, all with a confirmed diagnosis of visceral leishmaniasis. To identify the Leishmania species involved, patient samples were analyzed by microscopy, serologic studies, DNA detection, and sequencing. Variables such as age, sex, place of residence, clinical signs and symptoms consistent with visceral leishmaniasis were also recorded.Results: 75% (18/24) of the patients studied were males and 25% (6/24) were younger than 4 years. The most frequent symptom was a prolonged fever in 87.5% of the patients (21/24), followed by splenomegaly in 70.8% (17/24). Leishmania infantum was the only parasite species identified in all patients.Conclusion: This finding constitutes the first molecular identification of the Leishmania infantum species in autochthonous patients of Misiones province, Argentina. This study highlights the importance of PCR for species identification in epidemiological studies of visceral leishmaniosis in Argentina.Introducción. La leishmaniosis cutánea por Leishmania braziliensis ha sido tradicionalmente endémica en Argentina y se han sido descritos casos de compromiso visceral después de una leishmaniosis cutánea inicial. La leishmaniosis visceral emergió en Argentina en el año 2006 en la ciudad de Posadas, provincia de Misiones, afectando tanto a humanos como a perros.Objetivo. Identificar el agente etiológico a nivel de especie de los pacientes diagnosticados con leishmaniosis visceral en Misiones y describir sus características clínicoepidemiológicas.Materiales y métodos. Se estudió una serie de 24 pacientes con diagnóstico confirmado de leishmaniosis visceral en la provincia de Misiones en el período 2009 al 2016. Para la identificación de Leishmania spp., los pacientes fueron sometidos a estudios diagnósticos indirectos (serológicos) y directos (microscopía, detección de ADN y secuenciación). También, se estudiaron variables como edad, sexo, lugar de residencia, y signos y síntomas clínicos indicativos de leishmaniosis visceral.Resultados. De los 24 pacientes estudiados, 18 (75 %) eran hombres y 6 (25 %) eran menores de cuatro años. La manifestación clínica más frecuente fue el síndrome febril prolongado en 21 (87,5 %) de los pacientes, seguido de esplenomegalia en 17 (70,8 %). Se identificó la especie Leishmania infantum en todos los pacientes estudiados.Conclusión. Este hallazgo constituye la primera identificación de la especie L. infantum en pacientes autóctonos de la provincia de Misiones. El estudio evidenció la importancia de la PCR para el manejo epidemiológico de la leishmaniosis visceral en Argentina
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