176 research outputs found

    Bioadhesión sobre Alúmina. Propiedades superficiales

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    La alúmina es uno de los materiales cerámicos de mayor relevancia en usos biomédicos. Así, este trabajo hace una completa caracterización de su superficie a través de propiedades que son de especial importancia en aquellos procesos de interacción con superficies biológicas como son células y microorganismos. Tensión superficial, potencial zeta y rugosidad superficial se analizan utilizando métodos diversos. La tensión superficial se muestra en torno a 35 mJ m-2 aunque los valores dependen en muchos casos de la aproximación escogida y de los grupos de líquidos prueba necesarios para su determinación. El punto isoeléctrico aparece a pH = 4,6 lo que indica una carga superficial negativa cuando la alúmina se encuentre inmersa en líquidos fisiológicos (pH = 7). Los accidentes topográficos responsables de la macrorugosidad pueden considerarse de periodicidad en torno a 25um presentando alta variabilidad a escalas inferiores, por ello, es importante determinar la rugosidad a escalas próximas al tamaño de las células que intervienen en el proceso de adhesión

    Bactericidal effect of magnesium ions over planktonic and sessile Staphylococcus epidermidis and Escherichia coli

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    Magnesium and its alloys are in focus to produce implants due to their excellent mechanical properties, facility to decompose in the body, enhancement of new bone formation and antibacterial properties. However, there is still a lack of consensus about the origin of such antibacterial effect. Up to date, most antibacterial studies were performed over newly synthesized MgO particles, nanotubes or nanowires in the form of slurries, integrated within polymeric matrixes or as coatings of other bulk materials whereas the effect of pure Mg2+ions over bacteria viability, in the absence of secondary processes, has not been assessed yet. Hence, in this study, we have characterized the bactericidal effect of Mg2+ions over two different bacteria strains, Staphylococcus epidermidis (Gram-positive) and Escherichia coli (Gram-negative) controlling both pH and ion concentration. Also, we have considered the ion effect on dissimilar planktonic and sessile cells on surfaces with different hydrophobicity

    Broadband spectrally flat and high power density light source for fiber sensing purposes

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    We present a new kind of broadband continuous-wave source which outperforms any other broadband superluminescent or amplified spontaneous emission source both in terms of output spectral density and bandwidth. Our source covers the wavelength band of interest for fibre applications (from 1450 to 1625 nm) and has an output power of approximately 1.3 W. The source is obtained by pumping a conventional non-zero dispersion-shifted fibre with a continuous-wave Raman fibre laser tuned to the region of small anomalous dispersion of the fibre. The laser beam undergoes an extreme spectral broadening in the fibre. Our experimental results show clearly that the modulation instability (MI)-induced soliton fission is the key element leading to this spectral broadening. Modulation instability is seeded by fast intensity instabilities present in the laser output. We show that this source features good power stability and we believe that it might have very interesting applications in fibre sensing, for instance to avoid the need of amplification in the interrogation of remote Bragg gratings or to improve the resolution and dynamic range of optical coherence tomography setups.Ministerio de Educación y CienciaComunidad de Madri

    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

    Aircraft icing: in-cloud measurements and sensitivity to physical parameterizations

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    The prediction of supercooled cloud drops in the atmosphere is a basic tool for aviation safety, owing to their contact with and instant freezing on sensitive locations of the aircraft. One of the main disadvantages for predicting atmospheric icing conditions is the acquisition of observational data. In this study, we used in‐cloud microphysics measurements taken during 10 flights of a C‐212 research aircraft under winter conditions, during which we encountered 37 regions containing supercooled liquid water. To investigate the capability of the Weather Research and Forecasting model to detect regions containing supercooled cloud drops, we propose a multiphysics ensemble approach. We used four microphysics and two planetary boundary layer schemes. The Morrison parameterization yielded superior results, whereas the planetary boundary layer schemes were essential in evaluating the presence of liquid water content. The Goddard microphysics scheme best detected the presence of ice water content but tended to underestimate liquid water content

    Comparison of the WRF and HARMONIE models ability for mountain wave warnings

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    Mountain lee waves usually involve aircraft icing and turbulence events. These weather phenomena, in turn, are a threat to aviation safety. For this reason, mountain lee waves are an interesting subject of study for the scientific community. This paper analyses several mountain lee waves events in the south-east of the Guadarrama mountain range, near the Adolfo Suarez Madrid-Barajas airport (Spain), using the Weather Research and Forecasting (WRF) and the HARMONIE-AROME high-resolution numerical models. For this work, simulated brightness temperature from the optimum WRF parametrization schemes and from the HARMONIE are validated using satellite observations to evaluate the performance of the models in reproducing the lenticular clouds associated to mountain lee waves. The brightness temperature probability density shows interesting differences between both models. Following, a mountain wave characterization is performed simulating some atmospheric variables (wind direction, wind speed, atmospheric stability, liquid water content and temperature) in several grid points located in the leeward, windward and over the summit of the mountains. The characterization results are compared for both numerical models and a decision tree is developed for each to forecast and warn the mountain lee waves, lenticular clouds and icing events with a 24 to 48 h lead time. These warnings are validated using several skill scores, revealing similar results for both models

    Group and call effect in achieving success in a subject: Analyses of the "Biology and Botany" whole life in the E.U.I.T.A. (University of Seville)

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    La Biología y la Botánica son dos materias fundamentales en la formación de un ingeniero técnico agrícola. Sus contenidos se han ofrecido a veces en asignaturas independientes y, en otras ocasiones como la que nos ocupa, en una sola asignatura. Por otra parte, siempre se ha mirado con interés, e incluso preocupación, el efecto de la variable grupo, de forma independiente o relacionándola con su distribución en turnos de mañana o tarde, así como la importancia de la convocatoria (en los distintos momentos a lo largo del curso académico) en la que el alumno consigue superar la asignatura. Aquí presentamos los resultados en la consecución de objetivos por parte de los alumnos y, por ende, de los profesores y de la Universidad de Sevilla a lo largo de la totalidad de la vida de la asignatura "Biología y Botánica" dentro del plan de estudios 2003/04 para tres titulaciones simultáneas, desde su comienzo en el curso 2003/04 hasta su extinción en el curso 2009/10, de la E.U.I.T.A. (Escuela Universitaria de Ingeniería Técnica Agrícola) de la Universidad de Sevilla. Además se consideran convocatorias pertenecientes al período de extinción añadido. Los análisis toman en cuenta además el éxito en la superación de la asignatura tanto de forma cualitativa (aprobado o suspenso de la evaluación a la que el alumno se ha sometido) como cuantitativa (nota conseguida). Las conclusiones obtenidas permiten mirar los resultados y la consecución de objetivos, así como una potencial toma de decisiones para el futuro, basándose en un marco temporal amplio y objetivo.Biology and Botany are two critical issues in the formation of a technical agricultural engineer. Their topics are sometimes offered in separate subjects and, at other times as here, within a single one. Besides, it has always been considered with interest, and even concern, the effect of the variable group, independently or in relation to their distribution in the morning or afternoon turns, and the importance of the call (at different times during the academic year) at which the student gets to pass the subject. Here we present the results in the achievement of objectives by students, and therefore teachers and the University of Seville, along the entire life of the subject "Biology and Botany" within the teaching 2003/04 plan for three simultaneous academic programs, from its start in the course 2003/04 to its extinction in the course 2009/10, in the E.U.I.T.A. (University School of Technical Agricultural Engineering) of the University of Seville. Calls belonging to the period of extinction are also considered. Analyses are both qualitative, based on having success in passing the subject or not, and quantitative (mark scored). Obtained conclusions let us see the results and the achievement of objectives, as well as a potential decision-making for the future, with a base on a comprehensive and objective frame

    Effectiveness and safety of first-generation protease inhibitors in clinical practice: Hepatitis C virus patients with advanced fibrosis

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    AIM: To evaluates the effectiveness and safety of the first generation, NS3/4A protease inhibitors (PIs) in clinical practice against chronic C virus, especially in patients with advanced fibrosis. METHODS: Prospective study and non-experimental analysis of a multicentre cohort of 38 Spanish hospitals that includes patients with chronic hepatitis C genotype 1, treatment-nai¨ve (TN) or treatment-experienced (TE), who underwent triple therapy with the first generation NS3/4A protease inhibitors, boceprevir (BOC) and telaprevir (TVR), in combination with pegylated interferon and ribavirin. The patients were treatment in routine practice settings. Data on the study population and on adverse clinical and virologic effects were compiled during the treatment period and during follow up. RESULTS: One thousand and fifty seven patients were included, 405 (38%) were treated with BOC and 652 (62%) with TVR. Of this total, 30% (n = 319) were TN and the remaining were TE: 28% (n = 298) relapsers, 12% (n = 123) partial responders (PR), 25% (n = 260) null-responders (NR) and for 5% (n = 57) with prior response unknown. The rate of sustained virologic response (SVR) by intention-to-treatment (ITT) was greater in those treated with TVR (65%) than in those treated with BOC (52%) (P < 0.0001), whereas by modified intention-to-treatment (mITT) no were found significant differences. By degree of fibrosis, 56% of patients were F4 and the highest SVR rates were recorded in the non-F4 patients, both TN and TE. In the analysis by groups, the TN patients treated with TVR by ITT showed a higher SVR (P = 0.005). However, by mITT there were no significant differences between BOC and TVR. In the multivariate analysis by mITT, the significant SVR factors were relapsers, IL28B CC and non-F4; the type of treatment (BOC or TVR) was not significant. The lowest SVR values were presented by the F4-NR patients, treated with BOC (46%) or with TVR (45%). 28% of the patients interrupted the treatment, mainly by non-viral response (51%): this outcome was more frequent in the TE than in the TN patients (57% vs 40%, P = 0.01). With respect to severe haematological disorders, neutropaenia was more likely to affect the patients treated with BOC (33% vs 20%, P = 0.0001), and thrombocytopaenia and anaemia, the F4 patients (P = 0.000, P = 0.025, respectively). CONCLUSION: In a real clinical practice setting with a high proportion of patients with advanced fibrosis, effectiveness of first-generation PIs was high except for NR patients, with similar SVR rates being achieved by BOC and TVR
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