435 research outputs found

    Comparison of different numerical methods for the solution of the time-fractional reaction-diffusion equation with variable diffusion coefficient

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    In this work we perform a comparison of two different numerical schemes for the solution of the time-fractional diffusion equation with variable diffusion coefficient and a nonlinear source term. The two methods are the implicit numerical scheme presented in [M.L. Morgado, M. Rebelo, Numerical approximation of distributed order reaction- diffusion equations, Journal of Computational and Applied Mathematics 275 (2015) 216-227] that is adapted to our type of equation, and a colocation method where Chebyshev polynomials are used to reduce the fractional differential equation to a system of ordinary differential equationsCOMPETE, FEDER and Fundação para a Ciência e a Tecnologia (the Portuguese Foundation for Science and Technology (FCT)) through Strategic Projects - LA 25 – 2013-2014, PTDC/EME- MFE/113988/2009 and EXPL/CTM-POL/1299/2013. M. Rebelo acknowledge financial funding by the Portuguese Foundation for Science and Technology through the project PEstOE/MAT/UI0297/2013 (Centro de Matemática e Aplicacões

    Biological treatment of a contaminated gaseous emission from a paint and varnish plant—from laboratory studies to pilot-scale operation

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    A Vapour-Phase Bioreactor (VPB), namely a biotrickling filter, was scaled-up and operated in-situ for the treatment of gaseous emissions from a paint and varnish industrial plant. A microbial culture able to degrade the target compounds was enriched and a laboratory-scale VPB was established in order to evaluate the treatment's performance. The VPB presented removal efficiencies higher than 90% when exposed to Organic Loads (OL) of ca 50 g h−1 m−3 of reactor. The VPB was exposed to dynamic conditions often found in-situ (eg night and weekend shutdown periods) and showed a fast capacity to recover, with and without mineral medium recirculation. After a prolonged interruption period (10 months), the VPB was not able to cope with OL of ca 25 g h−1 m−3 of reactor and re-inoculation was required in order to recover the treatment performance. The VPB also showed limited treatment when exposed to higher OL (ca 500 g h−1 m−3 of reactor). The VPB was then scaled-up and a 3 m3 VPB was operated in-situ, showing removal efficiencies higher than 50% when exposed to an OL of c 5 g h−1 m−3 of reactor, thus complying with current legal demands. The addition of a maintenance feed was shown to be a useful tool for VPB pilot-scale operation when shutdown periods occurred. A factorial design of experiments was carried out, which allowed reduction to one-tenth of the initial supply of the main mineral medium constituents, namely phosphate buffer, ammonium and magnesium salts, and also elimination of the metal supplement. Overall, the VPBs were shown to be robust equipment, being able to respond actively to dynamic treatment scenarios, particularly night and weekend shutdown periods. Copyright © 2003 Society of Chemical Industr

    Fractura de estrés en la infancia: consideraciones diagnósticas sobre 9 casos

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    Las fracturas de estrés son lesiones que suelen estar en relación con ciclos repetidos de carga sobre un hueso normal sometido a un exceso de solicitaciones mecánicas o bien sobre un hueso con menor resistencia. Se presenta una revisión de 9 casos de fractura de estrés tratadas en el Hospital Infantil Miguel Servet de Zaragoza, en los últimos 10 años, con resultado de 5 niños y 4 niñas, con una edad media de 10,11 años (rango: 5-14). El tiempo de diagnóstico medio fue 17,6 días (rango: 1-92), y las localizaciones más frecuentes fueron los metatarsianos, la tibia y el cuello femoral. Solo dos de los casos estaban relacionados con la práctica deportiva. Todos presentaron clínica de dolor y alteración de la marcha. En uno de ellos se realizó un diagnóstico inicial de sospecha de sarcoma de Ewing. Todos fueron tratados de forma conservadora. El tiempo de seguimiento medio fue 23,92 meses (rango: 2-96).Stress fractures are injuries that are often related to repeated cycles of loading on a normal bone subjected to excessive mechanical stress, as well on a bone of less resistance. We present a review of 9 cases of stress fracture treated at Children's Hospital Miguel Servet in Zaragoza, in the last 10 years, resulting in 5 boys and 4 girls, mean age 10,11 years (3-14). Mean time for diagnosis was 17,6 days (1-92), and the most frequent location was metatarsals, tibia and femoral neck. Only two of the cases were related to sports. All of them presented clinical pain and abnormal gait. One patient received a suspect initial diagnosis of Ewing sarcoma. All were treated conservatively. The mean follow up was 23.92 months (2-96)

    Effect of cinnamon powder addition to a Portuguese custard tart (Pastel de Nata) on healthy adults' postprandial glycemia

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    Background and Objective: Cinnamon is a spice used over the years in cooking to impart aromatic, flavor and taste properties to food and beverages. Moreover, cinnamon has been used for its medicinal properties due to its potential phenolic content, which can protect against cardio-metabolic diseases. Previous studies reported an improvement of postprandial glycemia after addition of cinnamon powder to a high-sugar meal. The study aims at investigating the effect of adding cinnamon powder to a Portuguese custard tart (Pastel de Nata) on the postprandial glycemic response in healthy subjects. Subjects and Methods: After review board and Ethic Committee of the State approval, thirty-two healthy human subjects were assigned in a controlled study and randomly allocated into 2 groups: 16 subjects ingested a custard tart with cinnamon powder (cinnamon group) and 16 subjects ingested a custard tart alone (control group). Blood glucose concentrations were measured before interventions and after 30, 60, 90 and 120 minutes. Chemical analysis was performed to quantify the total phenolic content and antioxidant activity. Results: The postprandial blood glucose (PBG) area under the curve (AUC) was significantly lower (p = 0.0005) in the cinnamon group (599.2 ± 9.1) compared to the AUC of the control group (645.7 ± 7.7). The administration of cinnamon powder to the custard tarts slightly decreased PBG mean values compared to custard tart without cinnamon powder, although it did not reach statistical significance (p = 0.273). Cinnamon addition to custard tart improved the total phenolic content (1278.7 ± 0.7 compared to 253.7 ± 22.8 mg/L gallic acid) and antioxidant properties, increasing 4.4 times the capacity of free-radical scavenger compared with custard tart without cinnamon (IC50). Conclusion: The addition of cinnamon powder to custard tart could be beneficial to glycemic control

    Valorisation of natural extracts from marine source focused on marine by-products: A review

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    The wide chemical and biological diversity observed in the marine environment makes the ocean an extraordinary source of high added value compounds (HAVC) which can be employed in many applications. Minerals, lipids, amino acids, polysaccharides and proteins from marine sources have unique features and, surprisingly, their highest concentration is often found in parts of marine organisms that are commonly discarded. Fish heads, viscera, skin, tails, offal and blood, as well as seafood shells possess several HAVC suitable for human health applications, yet most end up as residues throughout the raw material processing. This review updates information on this issue and conveys critical analysis of the chief methodologies to carry out extraction, purification and eventual transformation, with a focus on their actual and potential applications.info:eu-repo/semantics/publishedVersio

    Elucidating the aryl hydrocarbon receptor antagonism from a chemical-structural perspective

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    The aryl hydrocarbon receptor (AhR) plays an important role in several biological processes such as reproduction, immunity and homoeostasis. However, little is known on the chemical-structural and physicochemical features that influence the activity of AhR antagonistic modulators. In the present report, in vitro AhR antagonistic activity evaluations, based on a chemical-activated luciferase gene expression (AhR-CALUX) bioassay, and an extensive literature review were performed with the aim of constructing a structurally diverse database of contaminants and potentially toxic chemicals. Subsequently, QSAR models based on Linear Discriminant Analysis and Logistic Regression, as well as two toxicophoric hypotheses were proposed to model the AhR antagonistic activity of the built dataset. The QSAR models were rigorously validated yielding satisfactory performance for all classification parameters. Likewise, the toxicophoric hypotheses were validated using a diverse set of 350 decoys, demonstrating adequate robustness and predictive power. Chemical interpretations of both the QSAR and toxicophoric models suggested that hydrophobic constraints, the presence of aromatic rings and electron-acceptor moieties are critical for the AhR antagonism. Therefore, it is hoped that the deductions obtained in the present study will contribute to elucidate further on the structural and physicochemical factors influencing the AhR antagonistic activity of chemical compounds

    New In Vitro studies on the bioprofile of Genista tenera antihyperglycemic extract

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    The inhibition of a-glucosidase and glucose-6-phosphatase, two enzymes involved in the carbohydrate metabolism, is an important target to control glycaemia on individuals with type 2 diabetes. In this work we report for the first time the inhibition of both enzymes by the antihyperglycemic n-butanol extract from Genista tenera (Fabaceae). This extract decreased a-glucosidase and glucose-6-phosphatase activities to 0.97 and 80.25 %, respectively, being more effective than acarbose, and phlorizin, the positive controls, which reduced enzymes activities only to 17.39 and 96.06 %. Once inflammation and oxidative stress are related to diabetic impairments, the anti-inflammatory activity of the extract was also evaluated, through its inhibitory activity over COX-1 enzyme (47.5 % inhibition). Moreover, after induction of oxidative stress by UV radiation, the viability of irradiated rat liver hepatoma cells exposed to the extract was significantly higher (67.82 %) than that promoted by ascorbic acid, the positive control (45.05 %). In addition, the stability of the extract under gastrointestinal conditions was evaluated by HPLC–DAD-ESI–MS/MS. Flavonoid diglycosides were identified as the main constituents of the extract, and no alterations in the chemical composition nor in the antioxidant activity were observed after in vitro digestion with artificial gastric and pancreatic juices.Fundação para a Ciência e a Tecnologia e Comissão Europeiainfo:eu-repo/semantics/publishedVersio

    Unidades litológicas del Neógeno en el extremo oeste de la Cuenca del Guadalquivir y su correlación con el sondeo Huelva-1 (Huelva - España)

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    A detailed surveying and a new geological map of the sheet at 1:50.000 number 999/1016 (Huelva - Los Caños), located at the west end of the Guadalquivir Basin, has been carried out. This data allows us to propose a new organization of the lithological units present at the west side of the Odiel River. These units include all the sedimentary record in this sector of the Guadalquivir Basin, ranging from Tortonian to Pliocene, but with shallower and coarser facies that are only present in this part of the basin. This fact is due to the location of the area, probably less subsiding due to a longer distance from Betic-Rif orogen. The lithological units are described concisely and a correlation with the core of the Huelva-1 borehole and with the outcrops of Huelva – Palos de la Frontera area is also proposed. The units are organized in a stack of sequences with a progradational pattern, typical of a basin margin, and highlighting a gradual reduction of the accommodation space in the late Messinian and during the Pliocene.Se ha realizado un reconocimiento detallado y un nuevo mapa geológico de la hoja a 1: 50.000 número 999/1016 (Huelva - Los Caños), situada en el extremo oeste de la Cuenca del Guadalquivir. Estos datos nos han permitido proponer una nueva organización de las unidades litológicas presentes en el lado oeste del río Odiel. Estas unidades incluyen el registro sedimentario completo de este sector de la Cuenca del Guadalquivir, que va desde Tortoniense al Plioceno, pero mostrando unas facies más someras y gruesas que solo están presentes en esta parte de la cuenca. Este hecho se debe a la ubicación de la zona, probablemente menos subsidente debido a su mayor distancia con respecto al orógeno Bético-Rifeño. Las unidades litológicas se describen de forma concisa y se propone también su correlación con el testigo del sondeo Huelva-1 y los afloramientos de la zona de Huelva - Palos de la Frontera. Las unidades litológicas se organizan formando un apilamiento de secuencias con un patrón progradacional, típico de un borde de cuenca, y ponen de manifiesto una reducción gradual del espacio de acomodación a finales del Messiniense y durante el Plioceno.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)Plan de Edición de Cartografía Geológica y Geomorfológica del IGME 2013-2016pu
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