Mercedes Zubiaur

CD38 is functionally dependent on the TCR/CD3 complex in human T cells

One of the functions of surface CD38 is the induction of phosphorylation of discrete cytoplasmic substrates and mobilization of cytoplasmic calcium (Ca2+). The present work addresses the issue of whether the signaling mediated via CD38 operates through an independent pathway or, alternatively, is linked to the TCR/CD3 signaling machinery. We studied the signals elicited through CD38 by the specific agonistic IB4 monoclonal antibody (mAb) by monitoring the levels of cytoplasmic Ca2+ and the induced phenotypic and functional variations in T cell growth. IB4 mAb presented the unique ability to increase cytoplasmic Ca2+ levels, which correlated with the phosphorylation of the PLC‐γ1. These effects were blocked by phorbol 12‐myristate 13‐acetate (PMA) and were dependent on the presence of a functional TCR/CD3 surface complex, no effects being recorded on mutant Jurkat cells lacking part of the CD3 structures. CD38 signaling appeared to share with TCR/CD3 the ability to induce apoptotic cell death in Jurkat T cells, an event paralleled by specific up‐regulation of the Fas molecule and inhibited by cyclosporin A. CD28, a costimulatory molecule, is synergized by increasing CD38‐induced apoptotic cell death. The results indicate the existence of a strong functional interdependence between CD38 and TCR/CD3.

CD38 ligation results in activation of the Raf-1/mitogen-activated protein kinase and the CD3-zeta/zeta-associated protein-70 signaling pathways in Jurkat T lymphocytes.

The effect of thermal annealing of charoite silicate K5 Ca8 (Si6O15) (Si2O7) (Si4O9) (OH)·3H2O have been studied by X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG) and thermoluminescence (TL). The chemical composition, analysed under electron probe micro-analysis (EPMA), indicates significant amounts of Na, Ba, Fe and F and the environmental scanning electron microscope (ESEM) results show impurities of unusual minerals such as tinaksite and aegirine. The cell parameters of both natural and preheated charoite, determined by XRD, are (i) a=[A] 19.786(2); b=[A] 32.003(3); c=[A] 7.8565(9); α=90o; β=97.159o; γ=90o with a Snyder FOM of 7.1932 for the non-annealed sample and (ii) a=[A] 19.567(2); b=[A] 31.821(3); c=[A] 7.1171(7); α=90o; β=94.000o(2); γ=90o; Snyders FOM 6.2637 for the preheated charoite. The thermal effect supposes an axes shortening, of Δa=0.219[A](2); Δb=0.182 [A]; Δc=0.7394 [A] and the β angle tilts only 3.159o. The DTA-TG and TL emission suggest: (i) a thermal gap of 80oC-290oC explained by charoite dehydration of different types of waters, i.e. hydrogen-Este trabajo esta financiado por un proyecto MAT2000-1361-C04- 01 del CICYT. O. Garcia y C. Gomez desean agradecer a la Comunidad Autonoma de Madrid (CAM) la financiacion de su beca postdoctoral.An accurate and precise morphometric modelling can be extended to past eruptions after a careful paleogeomorphological reconstruction of volcanic landforms in a setting of oceanic island. This reconstruction was used to create contour maps to derive the pre-, post-eruption and present-day digital elevation models (DEM). The right pixel size, interpolation method and quality of these DEMs were discussed. The process in a GIS framework of the geological information of cone, lava flow and tephra fall deposits together and the before-mentioned DEMs allowed determining the main morphological features of these volcanic landforms and their derivatives (e.g., eruption volume and pre-eruption slopes). The criteria needed to obtain accurate and precise measurements of the currently used morphometric parameters were defined. The calibration and validation of the morphometric modelling was performed on simulated volcanic landforms. The verification of the procedures was carried out on El Lentiscal volcano, a typical monogenetic basaltic eruption at Gran Canaria Island (Spain), the erosional history of which is in the first step of degradation. The proposed morphometric modelling is of general interest due to it is applicable to other geotectonic settings in the Earth and in the other inner planets of the Solar System.El presente trabajo ha sido realizado dentro de los proyectos CICYT MAT-97-0679-CO2-01 y MAT-97-0694-CO2-01.+. Albite sodium feldspar is studied by thermoluminescent methods using the blue region of the spectra (circa 400nm) and the possible uses as a dosimeter are explored. The light emission of the spectra bands of natural and irradiated albite under X and gamma rays are determined using automated RISO thermoluminescence equipment. Albite is a potential material to be used as retrospective dosimeter due to its good blue thermoluminescence characteristics in good agreement with the dosimetric requirements. It is sensitive to radiation, possesses a good linearity (0.06-8Gy), shows an acceptable stability in time, it is highly reproducible and can detect low levels of dose (60mGy). The TL glow curves emission exhibit a very complex structure associated to a continuous trap distribution. This behaviour could be explained as a consequence of a dynamic creation-annihilation of a [AlO 4 /alkali] + and [AlO 4 ] o centres.This work was supported by the “Comision Interministerial de Ciencia y Tecnologia” (CICYT-EU Spanish Government) under project AGL2010-15494/ALI, partially financed by European Regional Development Funds (ERDF) and Junta de Andalucia through financial support to group AGR-125. We also thank Elena Nogales Hernandez for technical assistance2 Pags. Trabajo originalmente presentado por los autores, en forma de Poster, en el VII Congreso de Mejora Genetica de Plantas (Zaragoza. 16-18 de septiembre de 2014)El presente trabajo ha sido parcialmente financiado por la Caja General de Ahorros de Canarias (Caja Canarias) y por el proyecto CGL2005-00239/BTE de la CICYT.A pesar de las similitudes cristaloquimicas entre los iones de cobre y los de plata, no existe ningun oxido mixto de cobre y plata ni natural ni sintetico. En este trabajo se presenta la sintesis a bajas temperaturas del primer oxido mixto de cobre y plata, de formula Ag2Cu2O3 (tetragonal, a=5.8857(3)A, c=10.6868(7)A, grupo espacial I41/amd, Z=4). Este oxido posee una estabilidad termica superior a los correspondientes oxidos de cobre y de plata. Contiene cadenas de iones Cu(II) cuadrado-planos que alternan con cadenas en zig-zag de Ag(I) con coordinacion lineal.Trabajo presentado en el KAAB International Symposium: Frontiers in Plant Science and Biotechnology, organizado por Kariwa Village Agro-Biotechnological Research Center, Niigata University y celebrado en dicha universidad el 29 de septiembre de 2014Plant transformation with tobamovirus replicase gene sequences is one of a number of available strategies for the potential control of tobamovirus disease. In most cases, a complete, near immunity type of resistance can be induced in plants transformed with fragments or modified forms of the viral replicase gene and the strong resistance is exhibited against high concentrations of both virus and viral RNA inoculum. However, the transgenic plant exhibits a relatively narrow resistance spectrum, manifested only against the virus from which the transgene is derived or against very closely related virus strains. A more complete understanding of the molecular mechanisms involved in replicasemediated transgenic resistance against tobamoviruses is needed, in order to increase its efficacy and reduce or eliminate the biosafety concerns related to its use in agriculture as a biotechnological tool for crop protection.Retention of the substituted urea herbicide thiazafluron (1, 3-dimethyl-1-(5-trifluoromethyl1 ,3,4-thiadiazol-2-yllureal by surface horizons of 6 soils of Southern Spain has been investigated. Soil retention has been expressed as the soil/water distribution coefficient Kd, calculated at 2 different thiazafluron solution concentration: Ci 0.05 and Ci = 0.5 m). Distribution coefficients ranged from 0.53 to 4.39 (Ci = 0.05 mM) and from 0.38 to 3.39 (Ci 0.5 mM) mmole adsorbed IKg soil/mmole dissolved/L solution. Soil clay content, and specially soil iHite content, appeared to be the most important single factors affecting thiazafluron adsorption by soils.4 paginas, 5 figuras, 4 tablas.-- Comunicacion oral presentada al Kautschuk-Herbst-Kolloquium (KHK) celebrado en Hannover (Alemania/2004).Trabajo presentado al IX Congreso Nacional de Investigacion Enologica (GIENOL) celebrado en Badajoz del 29 de mayo al 1 de junio de 2007.espanolEl objetivo de este estudio fue optimizar el angulo de posicionamiento del sensor Kinect para la reconstruccion de la estructura tridimensional de Xanthium strumarium L., Datura stramonium L. y Chenopodium album L., utilizando para ello algoritmos que permiten la captura y combinacion de imagenes de profundidad y RGB. Se han comparado diferentes angulos, fijando en cada uno de ellos el sensor Kinect de forma estatica respecto de la planta objetivo. Los resultados han confirmado la correlacion entre la biomasa de malas hierbas y el area estimada con el sensor. La estimacion de la altura de las plantas tambien fue adecuada, con una media de 2cm de error dependiendo de la posicion del sensor. Sin embargo, aunque el sensor ha mostrado su capacidad para la creacion de modelos tridimensionales, el adecuado posicionamiento del sensor es fundamental para la correcta reconstruccion de plantas. La posicion ideal del sensor debe ser elegida de acuerdo a la especie a medir y su estado fenologico. Estos resultados sugieren que Kinect es una herramienta util para caracterizar de forma rapida y fiable las malas hierbas, con importantes ventajas sobre otros sensores debido a su bajo coste, bajo requerimiento energetico y alta frecuencia de transmision de imagenes EnglishThe objective of this study was to optimize the positioning angle of a Kinect sensor for reconstructing the three dimensional structure of weeds, using Kinect fusion algorithms to generate a 3D point cloud from the depth video stream. The sensor was mounted in different positions facing the plant in order to obtain depth (RGB-D) images from different angles. The results confirmed the correlation between ground truth (e. g. weed biomass) and the measured area with Kinect. In addition, plant height was accurately estimated with a few centimeters error. However, although the Kinect sensor has shown its ability for plant reconstruction, proper positioning of the sensor is critical for correct reconstruction of plants. The best position of the sensor must be chosen according to the species to be measured and their growth stage. These results suggest that Kinect is a promising tool for a rapid and reliable weed characterization, with several important advantages such as low cost, low power requirement and a high frame rate.289 paginas.-- Mencion Internacional titulo de Doctor-- Tutor: Fernandez Boy, E. Dra. profesora titular de la Universidad de SevillaPlan Nacional de I+D+I 2004-2007 proyectos ref. HUM 2004-04861-C02 y C03), y HUM2004-03121/HISTEste trabajo ha sido realizado dentro de un proyecto financiado por la Comision Interministerial de Ciencia y Tecnologia de Espana (CICYT, Proyecto Ref. MAT2002-03891).Utilizado la informacion suministrada por el diagrama de equilibrio de fases Al2O3-MgO-CaO se ha disenado y obtenido un material de Al2O3-MgAl2O4-CaAl12O19-Ca2Mg2Al28O46 mediante sinterizacion reactiva de una mezcla de Al2O3 y CaMg(CO3)2. Las reacciones que tienen lugar en la mezcla durante el proceso se han estudiado usando tecnicas de analisis termico diferencial, termogravimetrico y dilatometria. Muestras reaccionadas a temperaturas seleccionadas se han estudiado por difraccion de rayos X y microscopia electronica de barrido con microanalisis mediante dispersion de energias. Los resultados obtenidos revelan que la reaccion entre las materias primas tiene lugar en varias etapas con formacion de fases transitorias, dando lugar a una microestructura final con granos aciculares de CaAl12O19 y particulas de la fase ternaria Ca2Mg2Al28O46 formadas en aquellos puntos en los que entran en contacto las fases de MgAl2O4 y CaAl12O19.53 paginas.-- Memoria presentada al XXXIV Curso Internacional de Edafologia y Biologia VegetalResumen del trabajo presentado a la IX Reunion de la Red Espanola de Levaduras celebrada en El Escorial (Madrid) en 2013.Lead zirconate titanate ceramic powders have been surface modified by using phosphor esther 0.3% in volume. The phosphorous modification gave higher densities at lower temperatures associated with a reduction of the weight losses during the densification process. From the relationships between ceramic processing and microstructure, it was established that the phosphorous surface modification allows the effective grain growth control as well a higher homogeneity in the grain size distribution.Ceramic materials based on BaTiO 3 modified with small amounts of antimony show interesting electric properties which make them valuable for electronic industry. These properties depend on the microstructure of the material, which is controlled by both the dopant concentration and the doping process. The aim of the present work is to study the microstructure development of Sb-doped BaTiO 3 materials for concentrations ranging from 0.05 to 0.6 mol%. Doping was carried out following two different methods, the traditional mixing of oxides and surface doping starting from Sb(O(CH) 3 CH 3 ) 3 . Materials sintered between 1300-1400°C show quite different microstructure. For surface doped materials, a Sb 2 O 3 concentration of 0.05 mol% leads to well densified materials with homogeneous fine-grained microstructure. On the other hand, the traditional oxide doped materials show exaggerated grain growth.Comunicacion oral dada en la XXIII Reunion de la Sociedad Espanola de Arcillas que tuvo lugar en Toledo (Espana) del 10 al 12 de septiembre de 2014.En el presente trabajo se ha estudiado el efecto que tienen las condiciones de tratamiento termico (entre 1350 y 1650oC) en la reaccion de formacion Al2TiO5, a partir de la mezcla equimolar de polvos finos (diametro promedio < 0.5�Em) de alumina y titania de elevada pureza. Se ha determinado la influencia de las condiciones de tratamiento termico en el grado de reaccion de formacion del Al2TiO5, el tamano de las celdas de Al2TiO5 formadas y en la eficiencia de la posterior molienda de los materiales. Los compactos preparados a partir de la mezcla de los polvos, fueron prensados isostaticamente. Parte de los compactos fueron tratados termicamente utilizando isotermas en el margen de temperaturas de 1350 y 1650oC. Otros compactos fueron sometidos a un tratamiento termico en dos etapas, tratados entre 1350 y 1500oC y, a continuacion se procedio a su molienda, posterior prensado y tratamiento utilizando isotermas a 1600oC. La evolucion de la reaccion se estudio mediante las tecnicas de difraccion de rayos X, microscopia optica y microscopia electronica de barrido. El estudio de la eficiencia de molienda se llevo a cabo mediante un analizador de tamano de particulas laser. Los resultados obtenidos indican la evolucion de la reaccion desde una matriz no reaccionada en compactos tratados a 1350��C, hasta la reaccion practicamente completa, salvo la presencia de particulas aisladas de alumina dentro de la matriz de Al2TiO5, en compactos tratados a 1650��C. El tipo de microestructura del Al2TiO5 formado, determinada por el tratamiento termico, afecta al posterior proceso de molienda de los materiales de Al2TiO5Se ha analizado el comportamiento tribologico de materiales de Si3N4 y de compuestos Si3N4/SiC, desde temperatura ambiente hasta 700oC y en el rango de velocidades 0.5-2 m/s. Los materiales se han preparado mediante prensado en caliente a 1750oC en atmosfera de nitrogeno, variando el contenido en fase �?- Si3N4, el tamano medio de grano, y la morfologia de las particulas de SiC adicionadas. Los ensayos se han realizado en pares homologos utilizando un tribometro del tipo punta sobre disco, sin lubricacion y a una carga constante de 5 N. Las superficies de desgaste de las puntas y los discos se observaron en un microscopio electronico de barrido con capacidad analitica (MEB-EDX). Los residuos generados durante los ensayos se analizaron mediante MEB-EDX y difraccion de rayos X (DRX). Los resultados obtenidos en los ensayos daban valores de coeficiente de friccion, f, y de desgaste, K, superiores a 0.3 y 10-6 mm3N-1m-1, respectivamente. El mecanismo de desgaste predominante dependia de la microestructura y de las propiedades mecanicas del material ensayado.Abstract The role of integration host factor (IHF) in the regulation of the sigma 54-dependent promoter Pu of the TOL plasmid of Pseudomonas putida has been examined. We have selected in vivo insertions of intrinsically curved DNA that restore the responsiveness of an IHF-binding site deletion variant of Pu to the cognate activator of the system, XylR. We found five Pu derivatives which had inserted a core sequence with 6 phased [A]6 tracts, flanked by different lengths of DNA at the location of the former IHF site. They displayed 40-100% of the activity of Pu, were independent of IHF, and maintained the overall geometry of the wild-type promoter. The induction patterns of Pu, compared to those of hybrid promoters, were virtually indistinguishable. This supports the notion that, in native conditions, IHF co-regulates the system by providing a structural aid for promoter architecture and not by interacting directly with the RNA polymerase, as it has been suggested with other known IHF-dependent promoters.Distribution coefficients oftwo organic contaminants, Ibe anionie herbicide alloxydim and Ibe polar compound nitrophenol, showed Ibat organic elays are good sorbents from water, through combination ofbolb hydrophobic and polar interaclions between organic contaminants and interlayer alkylammonium. Primary alkylammonium showed better efficiency Iban quaternary one, suggesting H-bonds between -NH and polar contaminants.Trabajo presentado al IX Congreso Nacional de Investigacion Enologica (GIENOL) celebrado en Badajoz del 29 de mayo al 1 de junio de 2007.The nucleotide sequences of the hpaB and hpaC genes encoding the 4-hydroxyphenylacetate 3-hydroxylase from Escherichia coli W ATCC 11105 have been determined. These genes appear to be part of an operon and encode two proteins of 58,781 and 18,679 Da, respectively, that are required for hydroxylase activity. This aromatic hydroxylase is NADH-dependent and uses FAD as the redox chromophore. The largest component (HpaB) has been purified by affinity chromatography in Cibacron blue. E. coli cells that express exclusively hpaB showed only a very low hydroxylase activity that was enhanced in the presence of extracts containing the smallest protein HpaC. This behavior resembles that of the coupling protein of the 4-hydroxyphenylacetate 3-hydroxylase from Pseudomonas putida, and it might prevent the wasteful oxidation of NADH in the absence of substrate. Using a promoter-probe plasmid we have demonstrated that the hpaBC operon is expressed by a promoter inducible by 4-hydroxyphenylacetic acid. A gene, named hpaA, encoding a protein homologous to the XylS/AraC family of regulators, was identified upstream of the hydroxylase operon. The role played by HpaA in the regulation of the hpaBC operon remains to be elucidated. Since HpaB is not homologous to other aromatic hydroxylases, we suggest that the E. coli 4-hydroxyphenylacetate 3-hydroxylase is the first member of a new family of two-component aromatic hydroxylases sequenced so far.Poster presentado en el XIII Congresso Luso-Espanhol de Fisiologia Vegetal, celebrado en Lisboa del 24 al 28 de julio de 2013.6 paginas, 3 figuras, 1 tabla, 19 referencias.-- XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on CLIMWATER 2010: Horticultural Use of Water in a Changing Climate. Lisboa, Portugal.In the present work, the theory of charge transport through active interfaces is used to study the electronic properties of ZnO-based varistors. It has been observed that for a certain range of sintering temperatures the microscopic electrical response of the material is constant, so that the macroscopic response is microstructure controlled. This allows controlling the functional response of the material with a high precision.1 .pdf copia del poster original (119 x 84 cm.) presentado por los autores. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).Alimentacion de la boga del Guadiana (Chondrostoma polylepis wi/lkommi, Stein. 1866) en la interfase rio-embalse de Sierra Boyera (Cordoba. Espana)Author wish to thank the financial support of this work to CICYT Project MAT2004-04843-C02-01.Desde finales de los anos sesenta, se ha despertado un gran interes por el uso de los materiales bioceramicos para aplicaciones biomedicas. En un trabajo previo, los autores hicieron una revision de los denominados materiales bioceramicos cristalinos en sentido estricto, es decir, de aquellos materiales, constituidos por compuestos inorganicos no metalicos, cristalinos y consolidados mediante tratamientos termicos a altas temperaturas. En el presente trabajo, los autores revisan el desarrollo de los vidrios bioactivos (biovidrios) y de las vitroceramicas bioactivas. Si bien todos ellos son obtenidos tambien por tratamiento termico a altas temperaturas, los primeros son amorfos y los segundos son obtenidos por desvitrificacion de un vidrio, si bien la fase vitrea normalmente predomina sobre las fases cristalinas. Despues de una introduccion al concepto de material bioactivo, se expone una breve revision historica del desarrollo de los vidrios bioactivos. A continuacion se describe su obtencion, reactividad en suero fisiologico artificial, mecanismo de union al tejido vivo y resistencia mecanica de la interfaz hueso-implante. Posteriormente, se expone el concepto de material vitroceramico y el proceso de su obtencion asi como tambien se describen los principales tipos de vidrios y vitroceramicos bioactivos (Bioglass®, Ceravital®, Cerabone®, Ilmaplant® and Bioverit®), sus composiciones, sus propiedades fisico-quimicas y sus comportamientos biologicos. Finalmente, se lleva a cabo tambien una corta revision de los recubrimientos con vidrios bioactivos y de los materiales compuestos (composites) bioactivos asi como de los usos mas comunes de los vidrios y vitroceramicos bioactivos.Este trabajo ha sido subvencionado por la CICYT dentro del proyecto MAT-2000-0941. JMRM agradece al AECI la concesion de una beca.6 paginas, 4 tablas, 4 referencias.-- International Symposium on Irrigation of Horticultural Crops, celebrado del 23-27 de noviembre 1992, en Almeria, Espana.The following ceramic materials have been synthesized from the mixed oxides route: Bi 4 Ti 3 O 12 (BIT), PbBi 4 Ti 4 O 15 (PBIT), Pb 2 Bi 4 Ti 5 O 18 (P2BIT), Pb 3 Bi 4 Ti 6 O 21 (P3BIT). These materials belong to Aurivillius bismuth layers compounds family. In the present work the integration factor m has the values 3, 4, 5 and 6, respectively. These materials have been conventionally sintered between 1000 and 1150°C, and by hot forging between 850 and 1000°C in order to obtain textured samples. The temperature of maximum density increases with the lead content, and the grain size decreases. For these temperatures the density was higher than 93% of the theoretical density. The lattice parameters of these materials were calculated from XRD patterns, the results indicate lineal dependency among parameter c and m. The orientation degree of the crystallographic planes of the textured compounds were calculated by the Lotgering formula, values higher than 90% in the BIT, PBIT y P2BIT have been obtained, and only 52% for P3BIT.espanolEl moldeo por inyeccion ha recibido una importante atencion para la manufactura de piezas de formas complejas y precisas que no se podrian obtener por otros metodos. Sin embargo, esta tecnica implica el uso de vehiculos de transporte polime¬ricos que llevan asociados una serie de problemas que limitan su aplicacion, como son la elevada temperatura de trabajo (120o-200o C), la compleja y costosa maquinaria, la alta presion de inyeccion (7–150 MPa), el rapido desgaste de los moldes, los largos ciclos necesarios para la eliminacion del material organico, etc. Estas caracteristicas son las res¬ponsables del escaso auge industrial de este proceso, quedando solo al alcance de las grandes corporaciones. Una alternativa satisfactoria para reducir los costos y la complejidad del proceso es la Inyeccion a Baja Presion. Recientemente se ha comprobado la posibilidad de emplear esta tecnica haciendo uso de suspensiones acuosas, lo que facilita enormemente la manipulacion, simplifica la maquinaria y abarata significativamente los costos. Esta tecnica permite reducir el contenido de material polimerico hasta un 2-3 % vol., respecto al 20–50 % vol., tipicamente usado en la tecnica de alta presion, de manera que no se requiere un tratamiento especial para su eliminacion, disminuyendo considerablemente el nivel de rechazos. En este trabajo se describen las ventajas y limitaciones del proceso de moldeo por inyeccion a baja presion (LPIM) en agua y se analizan los parametros criticos, como son las propiedades reologicas de la suspension a la temperatura de inyeccion y la influencia del aditivo gelificante, para la obtencion de piezas de Al2O3. EnglishInjection moulding has received a significant attention for manufacturing of precise, complex shaped parts which could not be obtained by other methods. However, this technique implies the use of polimeric transport vehicles, associated to some problems that limit its use, such as the high working temperature (120°C-200°C), the complex and expensive machinery, the high injection pressures (7-150 MPa), the moulds corrosion, the long cycles for burning out, etc. These characteristics are the responsible for the low industrial use of this process, only available for big companies. An useful alternative to reduce costs and process complexity is the low pressure injection moulding. It has been stated that this technique can be used from aque¬ous suspensions, thus largely facilitating handling, machinery and reducing costs. This technique allows to decrease the con¬tent of polymeric materials down to 2-3 vol%, respect to 20-50 vol%, tipically employed in the high pressure technique, in such a way that it is not necessary a specific treatment for burning out, and then the number of rejected parts is lower. In this work, the advantages and limitations of the low pressure injection moulding (LPIM) process in water are descri¬bed focusing critical parameters for the obtention of alumina parts, such as the rheological properties of the suspension at the injection temperature and the influence of the gelling additive.x Pags. Tesis elaborada en la EEAD-CSIC y presentada en la Univ. Zaragoza, Departamento de Ciencias de la Tierra. Comprende ocho articulos cientificos.Una de las reacciones que tiene lugar durante la sinterizacion de varistores ceramicos basados en el sistema ZnO-Bi2O3-Sb2O3 es la formacion de la fase Zn7Sb2O12, de estructura tipo espinela, que ocurre en el intervalo de temperaturas comprendido entre 900 y 1100oC, dependiendo de la composicion especifica del material. Esta fase es la responsable del control del crecimiento de grano y su distribucion en el seno del material como una segunda fase dispersa en la matriz mayoritaria de granos de ZnO determinara la cinetica del crecimiento de los granos. Sin embargo, el proceso de nucleacion y crecimiento de esta fase resulta dificil de controlar cuantitativamente, aspecto que se refleja en las caracteristicas finales del dispositivo varistor obtenido. En el presente trabajo se analiza el efecto de la incorporacion de la fase espinela previamente sintetizada a partir de los oxidos de zinc y antimonio. El analisis mediante Microscopia Electronica de Barrido (MEB) de la microestructura de muestras sinterizadas a diferentes temperaturas, revela un mayor control microestructural en los materiales en los que se ha incorporado la espinela sintetizada. La respuesta Intensidad-Voltaje de estos materiales es coherente con las caracteristicas microestructurales obtenidas, observandose una mayor reproducibilidad en el material.Trabajo presentado al IX Congreso Nacional de Investigacion Enologica (GIENOL) celebrado en Badajoz del 29 de mayo al 1 de junio de 2007.La industria del procesado del tomate tiene gran peso en la economia espanola debido a la alta produccion de tomates a nivel nacional; sin embargo, genera grandes cantidades de excedentes y residuos ricos en compuestos bioactivos, como el licopeno, poseedor de un gran potencial antioxidante que le confiere efectos beneficiosos para la salud. El aprovechamiento de dichos subproductos como fuente de ingredientes funcionales, supondria una importante reduccion en el gasto de las industrias procesadoras de tomate y evitaria graves problemas medioambientales. En los ultimos anos se estan realizando grandes esfuerzos destinados a mejorar los productos carnicos existentes y a lanzar al mercado otros nuevos en los que la composicion se haya modificado de alguna manera con el fin de que el producto resultante se cina mas a las nuevas orientaciones nutricionales. Una posible via para poder llevar a cabo esta demanda, seria enriquecer a los productos carnicos en compuestos bioactivos, convirtiendolos en alimentos funcionales...El objetivo de este trabajo es estudiar en un amplio rango de temperaturas (1000-1450oC) y mediante difraccion de rayos-X (DRX) las posibles reacciones en estado solido que pueden tener lugar en las regiones interfaciales de sistemas constituidos por composites NiO-Ce0.9Gd0.1O1.95 (NiO-GDC) con un 50% en peso de NiO, y de Cermets Ni- Ce0.9Gd0.1O1.95 (Ni-GDC) con un 39% en volumen Ni, y electrolitos basados en soluciones solidas Ce0.9Gd0.1O1.95 (GDC). Y asi mismo, estudiar la compatibilidad termoquimica y termomecanica entre los distintos materiales ceramicos que constituyen los sistemas electrolito/anodo.Se confirma mediante MEB y analisis EDAX que los sistemas cosinterizados entre 1350 y 1400oC durante 2h y constituidos por un electrolito basado en ceria (GDC) y un anodo basado en un cermet niquel-ceria (Ni-GDC), presentan una buena adherencia entre capas, sin la formacion de defectos y sin la presencia de interdifusion de especies a lo largo de la region interfacial. Es decir, se confirma que ambos materiales, Ni-GDC y GDC son compatibles termoquimica y termomecanicamente.The development of piezoelectric sensors for high frequency requires to work with very thin samples of material. At this thick nesses, the stress concentration produces strong perturbations in the materials, and the origin oF a non linear response, which depends field on working conditions. With the goal to advance in the knowledgement of this phenomenon, and by using Complex Impedance Spectroscopy, we have analysed the response of PZT ceramics with thickness of microns as a function of the applied and the amplitude of the analysis signal. These results allow to establish the base to the development of ultrasonic tunable sensors for high frequency.In this paper we investigate a propositional fuzzy logical system L? which contains the well-known Lukasiewicz, Product and Godel fuzzy logics as sublogics. We define the corresponding algebraic structures, called L?-algebras and prove the following completeness result: a formula f is provable in the L? logic iff it is a tautology for all linear L?-algebras. Moreover, linear L?-algebras are shown to be embeddable in linearly ordered abelian rings with a strong unit and cancellation law.Thermal diffusivity in ceramics by laser flash method Among the several techniques available to measure the thermal conductivity/ diffusivity, the laser flash method stands out for its low run time (less than 1 hour per temperature) and the reduced sample size required. Nevertheless, the laser flash technique is not very accurate for porous materials due to laser transmission problems and the underestimation of the total sample thickness. The attaching to the porous sample of two thin foils of an opaque and high diffusivity material (Cu) can solve these problems. This type of assembly was used to measure diffusivity in a porous alumina material. Data obtained are compared with theoretical models, wich predict effective thermal conductivity of the porous material from the thermal conductivity of the dense material, the amount of porosity and the type of microstructure.This work has been partially supported by CICYT in Project AMB93-81, and Junta de Andalucia through research group 4092.The alpine marmot occupies areas ranging in altitude from 1300 to 2800 m in the Pyrenees, although 67% of the colonies are found between 1800 and 2400 m. Greatest colony density and greater areal use than expected were found between these last limits. The lower edge of the altitudinal range normally coincides with current forest limit and the upper edge seems to be related to the availability of sufficient food as to accomplish its minimum annual cycle (maintenance, reproduction, and fat storage). There is a positive correlation between the number of colonies and the duration of the available food period above 1800 m. In a broad sense, the altitude range of the alpine marmot in the Pyrenees is similar to that in the Alps. Because the natural forest limit seems to be higher in the Pyrenees than in the Alps, the success of the introduction of the alpine marmot in the Pyrenees could be probably due to the existence of a wide supraforestal open area artificially created for pastoral use.Oral presentation given at the Euroclay 2015, held in Edinburgh (Scotland), on July 5-10th, 2015.El posible uso del nitruro de silicio en el ambito industrial se ve limitado por la dificultad y el coste que supone mecanizar geometrias complicadas. En el presente trabajo se estudia la posibilidad del uso de superaleaciones como interlamina de union entre piezas de este material. Se han seleccionado tres superaleaciones con base niquel-cromo debido a su interes tecnologico. Las uniones se han llevado a cabo por termocompresion en vacio, utilizando varias presiones y temperaturas. Se ha realizado un estudio comparativo de las intercaras de union en las tres aleaciones, analizando mediante microanalisis por energias dispersadas de Rayos X y microscopia electronica de barrido las reacciones que tienen lugar.Zircon (ZrSiO 4 ) is a mineral widely employed in the production of refractories, pigments, glazed tiles etc. The high radioactive content of this mineral stems from the presence of natural alpha emitters as U and Th. The radioactive activity of the 238 U, 235 U and 234 U, 228 Th, 230 Th and 232 Th radionuclides was measured by alpha spectrometry after isolation by radiochemical techniques. The alpha-emitters uranium and thorium irradiates internally the ceramic modifying the luminescence properties, this involves a potential use for dosimetric purposes. The thermoluminescence (TL) glow curve intensity of zircon is higher than the observed in other aluminosilicates measured under the same conditions. The TL maxima appearing at 280, 360 and 445°C are fairly well correlated with the differential thermal analysis (DTA). It suggests that this TL peaks could be linked to: (1) partial processes of local phase transitions and (2) alkali self-diffusion dehydroxylation phenomena when the sample is heated during the analytical measurement routine.Resumen del poster presentado a la I Reunion de Docencia y Difusion de la Microbiologia celebrada en Madrid del 12 al 13 de julio de 2012.El procesamiento coloidal de materiales ceramicos permite mejorar las propiedades finales de los productos, reduciendo el numero y tamano de los defectos, y aumentando la reproducibilidad del proceso. Esto exige, por una parte, el adecuado conocimiento de los parametros coloidequimicos y reologicos que rigen la estabilidad de la suspension y, por otra, el control de las variables especificas de cada proceso de conformado. La tecnica de colaje se ha utilizado tradicionalmente en la industria, dada su gran versatilidad, su bajo costo y la elevada uniformidad de las piezas asi obtenidas. Sin embargo, el desarrollo industrial impone la busqueda de nuevas tecnicas de conformado capaces de aunar las ventajas del colaje (como la posibilidad de obtener piezas de forma casi final, con el fin de reducir o eliminar la etapa de mecanizacion) con las propias de otros procesos (como los de prensado), como son la reduccion del ciclo de fabricacion y la automatizacion del proceso. Esto ha impulsado el desarrollo de nuevos procesos de conformado en los que la manipulacion de las propiedades coloidales de una suspension permiten obtener piezas de forma casi neta. En este trabajo se muestran las bases de dichas tecnicas y se discuten las tendencias actuales en el conformado coloidal de materiales ceramicos.Plenary lecture given at the 8th Mid-European Clay Conference, held in Kosice (Slovakia) on July 4-8th, 2016.Desde principios de este siglo, el cafe ha ocupado siempre el primer lugar en cuanto al valor de las exportaciones colombianas, y sus efectos sobre el resto del sistema economico y social han sido tan amplios que tradicionalmente se ha considerado como un sector esencial en la vida de Colombia no solo desde el punto de vista del crecimiento economico, sino, sobre todo, en funcion de lo que represento para la expansion de la frontera agricola y para la evolucion de la estructura social. Desde hace algun tiempo, sin embargo, hay otro producto, la cocaina, que ha venido a desplazar al cafe como primer producto de exportacion de Colombia. Y con ello, se abre el debate sobre si este ultimo producto ha jugado o no, en los ultimos anos, el papel que desempeno en otro tiempo el cafe como motor de transformaciones economicas y sociales.Tesis Doctoral para optar al Grado de Doctora en Quimica en la Universidad de Santiago (Departamento de Edafologia y Quimica Agricola).-- Composicion del Tribunal: Presidente: Ma Tarsy Carballas Fernandez; Vocal: Mercedes Casal Jimenez; Vocal: Carlota Garcia Paz; Vocal: Serafin Jesus Gonzalez Prieto; Secretario: Ma Teresa Barral Silva.-- Se adjunta tambien la imagen de la portadaEste trabajo ha sido financiado por la CICYT (proyecto BFM2002-00048). Los espectros de TL y RL se realizaron en la Univ. de Sussex (UK) con la ayuda del Prof. P.D. Townsend.La presente Tesis aborda el estudio de pretratamientos biologicos destinados a romper la barrera de lignina y mejorar la sacarificacion de los materiales lignocelulosicos utilizados en la obtencion de bioetanol de segunda generacion. Los pretratamientos estudiados en esta Tesis estan basados en el uso del sistema enzimatico lacasa-mediador y han demostrado ser eficaces en degradar/modificar la estructura del polimero de lignina que envuelve y protege a los carbohidratos. Las modificaciones en la estructura de la lignina permiten que los carbohidratos queden mas expuestos a las enzimas celulasas, lo que se traduce en una mejora significativa en la hidrolisis de los mismos. Por otro lado, esta Tesis tambien plantea el estudio de las interacciones que tienen lugar entre la lignina y las celulasas, y que afectan al proceso de hidrolisis de la celulosa. Estos estudios tienen como objetivo un aprovechamiento mas racional y eficaz de los materiales lignocelulosicos en la produccion de biocombustibles de segunda generacion (bioetanol). En esta Tesis se han evaluado dos sistemas lacasa-mediador. El primero esta constituido por una lacasa de alto potencial redox, obtenida del hongo basidiomiceto Pycnoporus cinnabarinus, y el mediador redox sintetico, 1-hidroxibenzotriazol (HBT). El segundo, incluye una lacasa comercial obtenida del hongo ascomiceto Myceliophthora thermophila y el mediador natural siringato de metilo (MeS). Los materiales lignocelulosicos utilizados en los pretratamientos enzimaticos con el sistema lacasa-mediador incluyeron: i) residuos agricolas de paja de trigo, el bagazo y la paja de la cana de azucar y ii) madera de paulownia (Paulownia fortunei). Para el estudio de las interacciones lignina-celulasa se utilizaron ligninas aisladas de eucalipto (Eucalyptus globulus), paja de trigo y picea (Picea abies) . Los pretratamientos de materiales lignocelulosicos con lacasa de P. cinnabarinus en presencia/ausencia de HBT, se realizaron sobre dos materias primas, los residuos agricolas de paja de trigo y de cana de azucar, con el objeto de mejorar el rendimiento de sacarificacion enzimatica y obtencion de bioetanol de ambas materias. Primeramente se realizaron experimentos del tratamiento sobre la paja de trigo en una secuencia que incluia un solo ciclo enzimatico seguido de una extraccion alcalina con peroxido de hidrogeno. Tras la secuencia se determino el contenido en lignina (lignina Klason) y se evaluo el efecto que esta eliminacion/modificacion de lignina producia sobre la sacarificacion enzimatica (con celulasas). Este pretratamiento produjo un descenso en el contenido en lignina del 45% respecto a la materia prima y una mejora en la obtencion de glucosa del 60% tras 72 h de tratamiento con celulasas. Tambien se analizo la modificacion de la estructura de lignina con dichos tratamientos mediante resonancia magnetica nuclear bidimensional (2DRMN). Estos estudios revelaron un descenso en los enlaces β-O-4´y β-5´ asi como en las unidades de lignina p-hidroxifenilo (H), guayacilo (G) y siringilo (S), y una disminucion mas moderada de los acidos p-cumarico y ferulico, sin variacion sustancial en la unidad de tricina. Con el objeto de estudiar la eficacia del sistema lacasa-mediador sobre otras materias primas, se estudio la aplicacion del mismo sobre los residuos de la industria de la cana de azucar (bagazo y paja), en este caso utilizando una secuencia de 4 ciclos con dosis menores de enzima y mediador por ciclo. Con esta secuencia se obtuvo un descenso en el contenido en lignina del 27% y 31% para el bagazo y paja de cana de azucar respectivamente, y una mejora del 39% y 46% en el rendimiento de glucosa, en la materia pretratada de bagazo y paja, en comparacion con el control, tras las 72 h de tratamiento con celulasas. El analisis 2D-RMN revelo notables cambios en la estructura de la estructura de la lignina, observandose en ambos materiales un descenso significativo en el numero los enlaces y unidades de lignina. La eficacia del sistema lacasa-mediador volvio a quedar demostrada con el pretratamiento realizado sobre madera de paulownia con la lacasa de M. thermophila y MeS. Dicho pretratamiento consto de una secuencia de 4 ciclos (cada uno de ellos incluia un tratamiento enzimatico seguido de una extraccion alcalina). Los mejores resultados se obtuvieron con 50 U·g-1 de enzima y 3% de MeS, consiguiendo un descenso en lignina del 24% respecto al control y un aumento en la liberacion de glucosa del 40%. Los analisis de 2D-NMR de estos materiales revelaron un descenso en el numero de enlaces y un aumento de las unidades oxidadas de siringilo y guayacilo, tras el pretratamiento. Por ultimo, se analizaron los filtrados obtenidos durante los diferentes ciclos, encontrandose compuestos oxidados de lignina como vainillina, acido vanilico, siringaldehido y acido siringico, que corroboran la naturaleza oxidativa del pretratamiento y la consecuente deslignificacion de los materiales lignocelulosicos. Con el fin de demostrar el efecto negativo que tiene la presencia de lignina sobre las celulasas en la hidrolisis del material lignocelulosico, se aislaron las ligninas (milled wood lignin, MWL) de diferentes materias primas (eucalipto, paja de trigo y picea), y se estudio su efecto en la adsorcion y consecuente inhibicion de las celulasas (tanto sobre el coctel enzimatico, como sobre la enzima purificada) mediante microbalanza de cristal de cuarzo y resonancia de plasmon superficial. Los resultados al aplicar las celulasas sobre films recubiertos de dichas ligninas demostraron que la enzima purificada muestra menor afinidad a la adsorcion sobre el film con lignina y mayor reversibilidad de union. Tambien se observo que la afinidad mas alta en la adsorcion lignina-enzima se produce en la lignina de picea (99% unidades G) mientras que la adsorcion mas baja se produjo en la de eucalipto (70% unidades S).6 paginas, 1 tabla, 2 figuras.-- El trabajo se genera en el marco de las actividades de la Reunion del Grupo de Trabajo Ecologia, Ecofisiologia y Suelos Forestales en Actas de la II reunion sobre suelos forestales.-- Nuevas perspectivas en las relaciones suelo-arbol.-- Salamanca, 22-23 de octubre 2007. http://www.irnase.csic.es/users/lventura/C25-Acta09.pdfFuel cells convert the chemical energy of a reaction into electrical energy in a continuous and direct way. The modular construction, noise and vibration absences, operating flexibility, much lower pollutants production and higher conversion efficiency make these devices very attractive for the future of energy sector. Among the different ongoing fuel cells, planar solid oxide fuel cell (SOFC) are very promising, The operation temperature is in the region of 800°C and they are specially aimed for electricity generation in small decentralized units. However, their price is not competitive yet in comparison with conventional technology because of several problems related to materials optimization. One of the important challenges is referred to the attainment of a seal that ensures the gas-tightness of the SOFCs at the operating temperature. Classes or glass-ceramics are the most adecuated materials to fulfil the sealing requirements for this application. In the present paper a worldwide overview is given outlining the different glasses and glass-ceramics employed On the sealing of SOFC so far, as well as their properties, advantages and drawbacks and a brief description about the SOFC technology. Finally, preparation and characterization to glass-ceramics from the system SiO 2 -BaO-RO-Al 2 O 3 is put forward as possible candidates for sealing SOFC.The phase transition to perovskite-type structure, that occurs in some hexagonal manganites when foreign cations are incorporated into solid solution, has been studied. Several solid solution series belonging to the Y(Mn, Ni)O 3 , (Er, Ca)MnO 3 , (Y, Ca)MnO 3 , systems have been prepared by solid state reaction between the corresponding oxides. The crystalline structure of the different solid solutions has been established. The behaviour of the (Gd, Ca)MnO 3 system has been taken as a reference. The obtained results are discussed as a function of the tolerance factor and the Mn 3+ /Mn 4+ ratio. The transition to perovskite structure is governed by this Mn 3+ /Mn 4+ ratio rather than the increase of the tolerance factor.En los ultimos anos se ha popularizado el empleo de tecnicas reometricas tales como la medida en esfuerzo controlado o los ensayos de oscilacion. En este trabajo se revisan los conceptos basicos de reologia de suspensiones y se analizan las tecnicas reometricas mas recientes para su completa caracterizacion. A partir de una suspension previamente optimizada de porcelana sanitaria, con un contenido en solidos de 50 % en volumen, se describen y analizan distintos tipos de ensayos reologicos, los modelos de regresion mas frecuentes y sus limitaciones y las posibles formas de representar los datos de un reograma para conseguir una maxima informacion. Se discuten las posibles diferencias entre los parametros reologicos obtenidos mediante distintas determinaciones reometricas, centrando el interes en la determinacion de los puntos de fluidez, clave para distinguir un comportamiento plastico de uno pseudoplastico.The development of new coating processes has important limitations related to the films thickness and the geometry of the coating substrates. In this work, two colloidal forming processes are proposed for manufacturing ceramic and metallic coatings on the inner surface of a steel pipe. Ceramic coatings of CaCO 3 have been formed by electrophoretic deposition (EPD). Aqueous stable suspensions were prepared and a electrophoretic cell was designed, in which the steel tube to be coated acted simultaneously as container and working electrode. Nickel films were prepared by filling the pipe with the suspension and rotating to fully wet the steel surface. Nickel suspensions were formulated focusing an improved wettability and adherence to the steel surface by using binders. From these processes, ceramic and metallic coatings with 300-350 μm in thickness, homogeneous and strongly adhered to the inner surface of the steel pipe have been obtained.211 Pags.- Figs.- Tabls. Tesis elaborada en el Departamento de Genetica y Produccion Vegetal, de la EEAD-CSIC (abril 2015) y presentada en la Universidad de Lleida (2016).The following review summarizes the last advances in technology of ceramic membrane. In the last years these membranes and their modules compete with organic membranes in many applications due to their high thermal and chemical stability, long life and good defouling properties. The sol-gel process is considered one of the best methods for ceramic membranes synthesis, because of its ability to make thin membrane top layers of nanoscale pore diameter, with narrow pore size distribution. Characterization methods such as gas permeation, bubble point test, N 2 adsorption-desorption, Hg penetration and microscopy allow to know the structure of the membrane.Trabajo presentado a la International Seafood Conference on the ocassion of the 25th anniversary of the WEFTA, celebrada en Noordwijkerhout (Netherlands) del 13 al 16 de noviembre de 1995.Los autores hacen constar su agradecimiento a La Comision Interministerial de Ciencia y Tecnologia, por las ayudas recibidas para la realizacion de este trabajo: ALI 91 0720, PTR 93 0061, ALI 94 0716 y ALI 95 0517.Las investigaciones sobre las epidemias de antracnosis en Andalucia han sido financiadas por los proyectos AGL96-1082 y AGL2000-1725 de la Comision Interministerial de Ciencia y Tecnologia (CICYT).Las propiedades de un material ceramico estan intimamente relacionadas con el procesamiento seguido para su obtencion, dado que este determina en gran medida su microestructura. En este trabajo se ha disenado un material ceramico, obtenido a partir de materias primas alternativas (residuos industriales y urbanos), encaminado a retener metales pesados en aguas contaminadas, siguiendo tres procesos distintos: colaje en molde de escayola, prensado uniaxial y extrusion. Para establecer una comparativa entre ellos se han preparado, en los tres casos, en forma de anillos Raschig. Se ha procedido a la caracterizacion fisicoquimica de los materiales asi obtenidos, observandose su microestructura mediante microscopia electronica de barrido, superficie especifica (BET), medidas de densidad en mercurio y helio, absorcion de agua y porosidad. Asimismo se ha realizado un ensayo dinamico de retencion de metales pesados con estos anillos en aguas simuladas, llevando a cabo analisis quimicos mediante ICP-OES en las aguas depuradas.Se presenta la sintesis y caracterizacion de la serie de disolucion solida Ag5Pb2-xCuxO6, (x = 0, 0.1, 0.3, 0.5). La sintesis se llevo a cabo mediante coprecipitacion de los nitratos de Ag(I), Pb(II) y Cu(II) en medio basico. La estructura de la serie es la del oxido Ag5Pb2O6, con el Cu(II) ocupando parcialmente los sitios octaedricos del Pb(IV). Esta sustitucion induce cambios interesantes en las propiedades de transporte electrico de los miembros de la serie, que van desde conductividad metalica a comportamiento semiconductor. El analisis Rietveld para el oxido Ag5Pb1.5Cu0.5O6, mostro un modelo estructural optimo en el que Pb y Cu comparten el sitio octaedrico en una distribucion desordenada (Pm1, a = 5.8306(9) A, c = 6.3430(6) A, V = 187.37 A3)La problematica de la inmigracion en Espana esta de plena actualidad. No hay dia en que uno abra un periodico y no encuentre noticias relacionadas, de un modo u otro, con la cuestion, aunque la poblacion extranjera no sea tan numerosa como para explicar este hecho. Lo cierto es que la situacio parece haber cogido por sorpresa al pais, que en su nueva condicion de receptor, cuando hasta hace poco sufria el proceso contrario, parece desconcertado. Este trabajo pretende ilustrar en cifras esa problematica, aspecto que creemos esencial para entender las dificultades de la sociedad para afrontar los retos que plantea la nueva situacion.Lead titanate has been prepared by a sol-gel method using titanium alkoxide and lead acetate. The addition of solid PbTiO 3 nanometer-size seeding particles (5wt%) into the precursor solution plays a crucial role during the crystallisation process. Comparing with the unseeded gels, the fraction of crystallised PbTiO 3 increases for the same temperatures of treatment. Besides, seeding reduce the presence of pyrochlore secondary phases, without using lead-rich compositions. These first results could indicate that the perovskite phase is formed directly from the amorphous phase.Paper presented at the Pure and Applied Chemistry International Conference (PACCON2014) held in Khon Kaen (Thailand) on January 8-10th 2014.En el presente trabajo se han obtenido carbonitruros de titanio TiCxN1-x de alta pureza y con caracter nanometrico, por molienda reactiva (MSR) de alta energia en un molino planetario, a partir de la mezcla de titanio con grafito o nanofibras de carbono (CNFs) en una atmosfera de nitrogeno. Una metodologia prometedora para el desarrollo de estos materiales consiste en el acoplamiento de la tecnica MSR con el sinterizado por SPS. El producto obtenido se ha sinterizado a 1400 oC y 1700 oC, obteniendose una ceramica monolitica totalmente densa (>99% d.t). En este trabajo se analizan las distintas microestructuras obtenidas en funcion del precursor de carbono y el tratamiento de SPS, evaluando las principales propiedades mecanicas de los materiales resultantes.We have investigated the frequency of replication origin usage in bacterial plasmids containing more than one potential origin. Escherichia coli recA- cells were selectively transformed with pBR322 monomers, dimers, or trimers. Plasmid DNA was isolated and digested with a restriction enzyme that cut the monomer only once, and the replicative intermediates (RIs) were analyzed by neutral/neutral two-dimensional agarose gel electrophoresis. Evidence for initiation outside the linearized plasmid was found only for oligomers. Moreover, in dimers, the intensity of the signal indicative for external initiation was equivalent to that reflecting internal initiation, whereas it was approximately twice as strong in trimers. To determine whether initiation could occur simultaneously at two origins in a single plasmid, we studied the replication of a neodimer in which both units could be unambiguously distinguished. The results showed that although both origins were equally competent to initiate replication, only one was active per plasmid. These observations strongly suggest that in ColE1 plasmids, replication initiates at a single site even when there are several identical potential origins per plasmid. In addition to the conventional two-dimensional gel patterns, novel specific patterns were observed with intensities that varied from one DNA sample to another. These unique patterns were the result of breakage of the RIs at a replication fork. This type of breakage changes both the mass and shape of RIs. When the entire population of RIs is affected, a new population of molecules is formed that may generate a novel pattern in two-dimensional gels.Los vidrios de composicion molar 50SiO2?30BaO?20ZnO (Zn1.5-50), 55SiO2?27BaO?18ZnO (Zn1.5-55), y 55SiO2?27BaO?18MgO (Mg1.5-55) presentan buenas propiedades para su aplicacion en el sellado de pilas de combustible de oxido solido de configuracion plana y temperatura de operacion intermedia (850oC) (IT-SOFC). El sellado debe producirse a traves de la sinterizacion del polvo de vidrio, durante el arranque de la pila, a temperaturas entre 700 y 850oC. El tratamiento posterior a la temperatura de operacion da lugar a la cristalizacion de silicatos de bario con el consiguiente aumento de viscosidad y rigidez del sello. Este trabajo es un estudio del comportamiento de sinterizacion de estos vidrios utilizando diferentes velocidades de calentamiento y distribuciones de tamano de particula del polvo de vidrio, para la obtencion final de sellos densos y homogeneos. Los vidrios Zn1.5-55 y Mg1.5-55 con un tamano de particula <63 µm y tratados a 2oC/min alcanzan densidades finales superiores al 95%. Por otra parte, se ha demostrado el buen acuerdo entre las cineticas de densificacion obtenidas experimentalmente y las predichas por el modelo de sinterizacion de formacion de Clusters en ausencia de cristalizacion concurrente.A strong interest in the use of ceramics for biomedical engineering applications developed in the late 1960´s. Used initially as alternatives to metallic materials in order to increase the biocompatibility of implants, bioceramics have become a diverse class of biomaterials, presently including three basic types: relatively bioinert ceramics; bioactive or surface reactive bioceramics and bioresorbable ceramics. This review will only refer to bioceramics “sensus stricto”, it is to say, those ceramic materials constituted for nonmetallic inorganic compounds, crystallines and consolidated by thermal treatments of powders to high temperatures. Leaving bioglasses, glass-ceramics and biocements apart, since, although all of them are obtained by thermal treatments to high temperatures, the first are amorphous, the second are obtained by desvitrification of a glass and in them vitreous phase normally prevails on the crystalline phases and the third are consolidated by means of a hydraulic or chemical reaction to room temperature. A review of the composition, physiochemical properties and biological behaviour of the principal types of crystalline bioceramics is given, based on the literature data and on the own experience of the authors.  , tricalcium phosphate Materiales bioceramicos cristalinos A finales de los anos sesenta se desperto un gran interes por el uso de los materiales ceramicos para aplicaciones biomedicas. Inicialmente utilizados como una alternativa a los materiales metalicos, con el proposito de incrementar la biocompatibilidad de los implantes, las bioceramicas se han convertido en una clase diversa de biomateriales, incluyendo actualmente tres tipos: ceramicas cuasi inertes; ceramicas bioactivas o reactivas superficialmente y ceramicas reabsorbibles o biodegradables. En la presente revision se hace referencia a las bioceramicas en sentido estricto, es decir, a aquellos materiales constitutitos por compuestos inorganicos no metalicos, cristalinos y consolidados mediante tratamientos termicos a altas temperaturas. Dejando aparte los biovidrios, los vitroceramicos y los biocementos, puesto que, si bien todos ellos son obtenidos por tratamiento termicos a altas temperaturas, los primeros son amorfos, los segundos son obtenidos por desvitrificacion de un vidrio, prevaleciendo normalmente la fase vitrea sobre las fases cristalinas, y los terceros son consolidados mediante una reaccion quimica o hidraulica a temperatura ambiente. Asi pues, teniendo en cuenta la abundante bibliografia sobre el tema y la experiencia propia de los autores, se presenta una revision de la composicion, propiedades fisicoquimicas, aplicaciones y comportamiento biologico de los principales tipos de bioceramicas cristalinas. Palabras clave: alumina, zircona, alumina-circona, grafito, hidroxiapatito, silicatos bioactivos, bioeutecticos  , fosfato tricalcico.Studied the distribution and colonization process of Alpine marmot (Marmota marmota L.) in the Southern Pyrenees. Marmots became extinct at the end of the Pleistocene in the Pyrenees, and have been introduced since 1948 on the northern slope of the mountain range (France). More than 350 localizations have been recorded. Results show factors that have affected its expansion, such as: orographic barriers, mountain passes, habitat selection and human disturbance. Location is given in 2 × 2 km of the UTM squares, which indicates the existence of at least one colonyThe glass ionomer cements have been used successfully in dentistry for more than 20 years. A problem of these cements is the release of Al 3+ ions to the physiological medium, being able to cause irreversible health problems to the patients. With the purpose of avoiding this problem, cements, from the reaction between the polyacrylic acid and wollastonita (CaSiO 3 ) in a water solution of tartaric acid, have been obtained and characterized. The results have shown that these cements reach compression strength values similar to those of the conventional cements of vitreous polyalqueonate. Additionally, the obtained cements are biocompatibles and bioactives.Trabajo presentado en la XXIX Reunion de la Sociedad Espanola de la Ciencia del Suelo (SECS), celebrada en Mallorca (Espana), del 3 al 6 de septiembre de 2013Trabajo presentado en el X Congreso de la Sociedad Espanola de Malherbologia (SEMh), celebrado en Huelva (Espana), del 5 al 7 de octubre de 2005Trabajo presentado a las Jornadas sobre tecnicas de neutrones, celebradas en Deusto (Bilbao) en septiembre de 1990.SUMMARY The aim of this work was to explore the potential use of the hydrotalcite compound [Mg3Al(OH),1,C03.xH,O, (HT), and its calcined produet Mg3AlO.(OH), (HT500), as sorbents of 2,4,6-trinitrophenol (TNP). The amounts of TNP removed by HT depends on the pH, whereas those removed by HT500 depends on solid/solution ratio.Se ha estudiado la interdependencia entre la densidad en verde y el tamano de particula en la sinterizacion reactiva de mezclas de circon � dolomita. El tamano del polvo se ha determinado con un analizador de particula por laser y se ha controlado variando el tiempo de molienda en un molino de atricion. Se ha observado que para un mismo metodo de consolidacion la densidad de los compactos, en verde, esta relacionada con la distribucion de tamano de particula. La densidad en verde y el grado de aglomeracion influyen sobre la sinterizacion de la mezcla de polvos. Los datos experimentales indican que compactos con similar densidad en verde y menor numero de aglomerados presentan un mejor comportamiento durante la sinterizacion. Se ha probado que los parametros significativos en el proceso son el tamano de particula y/o aglomerado y caracteristicas de la mezcla tales como homogeneidad y grado de compactacion.Se presentan dos diferentes rutas de sintesis de nanopolvos de Ce0.9Gd0.1O1.95 (CGO): precipitacion de hidroxidos, a partir de soluciones de nitratos utilizando amonia como agente precipitante y formacion de complejos polimerizados etilene-glicol nitratos metalicos. Las caracteristicas de los polvos se determinaron por DRX, microscopia de transmision (TEM), superficie especifica por Brunauer-Emmett-Teller (BET), y ensayos de ATD/ATG. El grado de aglomeracion de los nanopolvos y la uniformidad de los compactos en verde se ha observado por Microscopia electronica de barrido, (SEM). El tamano de poro de los compactos en verde se ha medido mediante porosimetria de Hg. El comportamiento a la sinterizacion se ha evaluado por dilatometria a velocidad de calentamiento constante y por sinterizacion isoterma a diferentes temperaturas. La evolucion microestructural se ha seguido por SEM.We study the determination of weights for two types of aggregation operators: the weighted mean and the OWA operator. We assume that there is at our disposal a set of examples for which the outcome of the aggregation operator is known. In the case of the OWA operator, we compare the results obtained by our method with another one in the literature. We show that the optimal weighting vector is reached with less cost.

A novel isoform of the Ly108 gene ameliorates murine lupus

The expression of the new Ly108 isoform H1 weakens lupus-like disease of C57BL/6.Sle1b mice.

Exosomes from human lymphoblastoid B cells express enzymatically active CD38 that is associated with signaling complexes containing CD81, Hsc-70 and Lyn.

Exosome vesicles of endocytic origin are involved in communication between tumor and immune cells. In addition, membrane rafts (MR) may support the sorting of proteins associated with exosomes. CD38 is found at the plasma membrane and in recycling endosomes, which are both redistributed toward the immunological synapse (IS) upon T cell antigen receptor (TCR) engagement. The data of this study provide evidence that CD38 is expressed on the surface of secreted exosomes derived from lymphoblastoid B cells. Exosomic CD38 is associated with the signaling molecules CD81, Hsc-70 and Lyn. Likewise, in MR, CD38 is associated with CD81, CD19, Lyn, Galphai-2, Hsc-70 and actin. Therefore, a high degree of overlap in the pattern of signaling proteins associated with CD38 in exosomes and MR exists. Exosomic and MR CD38, by virtue of these interactions, have signaling potential. Indeed, CD38 is enzymatically active in both exosomes and MR, and CD38 ligation induces Akt/PKB and Erk activation, which is accompanied by increased translocation of CD38 into MR. In conclusion, the present study indicates that CD38 localizes to MR, where it promotes cell signaling, and it is exported out of the cells through the exosome-mediated exocytic pathway, where it may act as an intercellular messenger.

Atheroma plaque, metabolic syndrome and inflammation in patients with psoriasis

BACKGROUND Chronic inflammation plays an important role in the development of cardiovascular risk factors. Although the prevalence of comorbidities and cardiovascular events has been described in patients with psoriasis, few studies have examined subclinical atherosclerosis in psoriasis patients. OBJECTIVE Our objective was to investigate the prevalence of atheroma plaques in patients with severe psoriasis compared with control subjects and to analyze the association with metabolic syndrome, homocysteine levels and inflammatory parameters. PATIENTS AND METHODS This case-control study included 133 patients, 72 with psoriasis and 61 controls consecutively admitted to the outpatient clinic in Dermatology Departments (Granada, Spain.) RESULTS Carotid atheroma plaques were observed in 34.7% of the psoriatic patients versus 8.2% of the controls (p=0.001) and metabolic syndrome was diagnosed in 40.3% of the psoriatic patients versus 13.1% of the controls (p<0.001). Significantly higher mean values of insulin, aldosterone, homocysteine and acute phase parameters (fibrinogen, D-dimer, C reactive protein and erythrocyte sedimentation rate) were found in psoriatic patients. Binary logistic regression showed a strong association between psoriasis and atheroma plaque and metabolic syndrome after controlling for confounding variables. LIMITATIONS The absence of longitudinal quantification of metabolic syndrome parameters and intima-media thickness in psoriatic patients. CONCLUSION The chronic inflammation and hyperhomocysteinemia found in psoriatic patients may explain the association with atheroma plaque and metabolic syndrome. Cardiovascular screening by metabolic syndrome criteria assessment and carotid ultrasound in psoriasis may be useful to detect individuals at risk and start preventive treatment against the development of cardiovascular disease.

Antigen-induced clustering of surface CD38 and recruitment of intracellular CD38 to the immunologic synapse

During immunologic synapse (IS) formation, human CD38 redistributes to the contact area of T cell-antigen-presenting cell (APC) conjugates in an antigen-dependent manner. Confocal microscopy showed that CD38 preferentially accumulated along the contact zone, whereas CD3-zeta redistributed toward the central zone of the IS. APC conjugates with human T cells or B cells transiently expressing CD38-green fluorescent protein revealed the presence of 2 distinct pools of CD38, one localized at the cell membrane and the other in recycling endosomes. Both pools were recruited to the T/APC contact sites and required antigen-pulsed APCs. The process appeared more efficient in T cells than in APCs. CD38 was actively recruited at the IS of T cells by means of Lck-mediated signals. Overexpression of CD38 in T cells increased the levels of antigen-induced intracellular calcium release. Opposite results were obtained by down-regulating surface CD38 expression by means of CD38 siRNA. CD38 blockade in influenza HA-specific T cells inhibited IL-2 and IFN-gamma production, PKC phosphorylation at Thr538, and PKC recruitment to the IS induced by antigen-pulsed APCs. These results reveal a new role for CD38 in modulating antigen-mediated T-cell responses during IS formation.

Increased gene expression of Toll-like receptor 4 on peripheral blood mononuclear cells in patients with psoriasis

Background  A role for the innate immune system in driving the autoimmune T cell cascade in psoriasis has been proposed. Toll‐like receptors‐(TLR)‐2 and ‐4 play a role in inflammation, atherosclerosis, and their specific role in psoriasis remains unclear.

Mice deficient in CD38 develop an attenuated form of collagen type II-induced arthritis

CD38, a type II transmembrane glycoprotein expressed in many cells of the immune system, is involved in cell signaling, migration and differentiation. Studies in CD38 deficient mice (CD38 KO mice) indicate that this molecule controls inflammatory immune responses, although its involvement in these responses depends on the disease model analyzed. Here, we explored the role of CD38 in the control of autoimmune responses using chicken collagen type II (col II) immunized C57BL/6-CD38 KO mice as a model of collagen-induced arthritis (CIA). We demonstrate that CD38 KO mice develop an attenuated CIA that is accompanied by a limited joint induction of IL-1β and IL-6 expression, by the lack of induction of IFNγ expression in the joints and by a reduction in the percentages of invariant NKT (iNKT) cells in the spleen. Immunized CD38 KO mice produce high levels of circulating IgG1 and low of IgG2a anti-col II antibodies in association with reduced percentages of Th1 cells in the draining lymph nodes. Altogether, our results show that CD38 participates in the pathogenesis of CIA controlling the number of iNKT cells and promoting Th1 inflammatory responses.

Increased expression and phosphorylation of the two S100A9 isoforms in mononuclear cells from patients with systemic lupus erythematosus: a proteomic signature for circulating low-density granulocytes.

Proteins differentially expressed in peripheral blood mononuclear cells (PBMCs) from systemic lupus erythematosus (SLE) patients versus Normal controls were identified by 2-DE and MALDI-MS. Thus, S100A9 expression was significantly increased in SLE PBMCs relative to Normal PBMCs at both mRNA and protein levels. Increased S100A9 levels in SLE PBMCs correlated positively with the abnormal presence of low-density granulocytes (LDGs) detected by flow-cytometry in the mononuclear cell fractions. Another set of proteins that were differentially expressed in SLE PBMCs formed S100A9-independent clusters, suggesting that these differences in protein expression are in fact reflecting changes in the abundance of specific cell types. In SLE PBMCs spots of the two S100A9 isoforms, S100A9-l and S100A9-s, and their phosphorylated counterparts were identified and confirmed to be phosphorylated at Thr(113) by MS/MS analyses. In addition, the phorbol ester PMA alone or in combination with ionomycin induced a stronger increase in threonine phosphorylation of S100A9 in SLE than in Normal PBMCs, while the same stimuli caused the opposite effect on phosphorylation and activation of Erk1/2, suggesting the existence of an abnormal S100A9 signaling in SLE PBMCs. Therefore, the expansion and activation of LDGs in SLE seems to underlie this prominent S100A9 signature.

Increased CD38 expression in T cells and circulating anti-CD38 IgG autoantibodies differentially correlate with distinct cytokine profiles and disease activity in systemic lupus erythematosus patients

CD38 is a multifunctional protein possessing ADP-ribosyl cyclase activity responsible for both the synthesis and the degradation of several Ca(2+)-mobilizing second messengers. In mammals, CD38 also functions as a receptor. In this study CD38 expression in CD4(+), CD8(+), or CD25(+) T cells was significantly higher in systemic lupus erythematosus (SLE) patients than in Normal controls. Increased CD38 expression in SLE T cells correlated with plasma levels of Th2 (IL-4, IL-10, IL-13) and Th1 (IL-1β, IL-12, IFN-γ, TNF-α) cytokines, and was more prevalent in clinically active SLE patients than in Normal controls. In contrast, elevated anti-CD38 IgG autoantibodies were more frequent in clinically quiescent SLE patients (SLEDAI=0) than in Normal controls, and correlated with moderate increased plasma levels of IL-10 and IFN-γ. However, clinically active SLE patients were mainly discriminated from quiescent SLE patients by increased levels of IL-10 and anti-dsDNA antibodies, with odds ratios (ORs) of 3.7 and 4.8, respectively. Increased frequency of anti-CD38 autoantibodies showed an inverse relationship with clinical activity (OR=0.43), and in particular with the frequency of anti-dsDNA autoantibodies (OR=0.21). Increased cell death occurred in CD38(+) Jurkat T cells treated with anti-CD38(+) SLE plasmas, and not in these cells treated with anti-CD38(-) SLE plasmas, or Normal plasmas. This effect did not occur in CD38-negative Jurkat T cells, suggesting that it could be attributed to anti-CD38 autoantibodies. These results support the hypothesis that anti-CD38 IgG autoantibodies or their associated plasma factors may dampen immune activation by affecting the viability of CD38(+) effector T cells and may provide protection from certain clinical SLE features.