Modelización por métodos numéricos de la degradación térmica de un elemento estructural de madera en situación de incendio

La cuantificación de la reducción de las propiedades resistentes y de la sección de un elemento estructural en situación de incendio es fundamental de cara a garantizar la estabilidad estructural en situación de incendio. Existen investigaciones que tratan de determinar la variación de las propiedades térmicas y mecánicas de la madera sometida a cargas térmicas, y la reducción de sección transversal de un elemento estructural de madera. La normativa europea en materia de construcción con madera, el Eurocódigo 5, propone unas simplificaciones para determinar la sección residual de un elemento estructural de madera en situación de incendio. Los objetivos de este trabajo comprenden una revisión de algunos trabajos realizados en el campo de la variación en función de la temperatura de las propiedades térmicas de la madera (calor específico, densidad y conductividad térmica), y la construcción con los distintos valores propuestos de varios modelos de elementos finitos que se someterán a cargas térmicas definidas por la curva ISO 834-1. Los resultados se compararán con un modelo construido con los valores que el Eurocódigo propone y con un ensayo experimental. Como resultado final, se propone finalmente un modelo de elementos finitos que emule el comportamiento del ensayo experimental. The quantification of the decrease of strength properties and section of a structural element in a fire situation is critical in order to guarantee the structural stability in such a fire event. There are some researches in literature trying to find the variation of thermal and mechanical properties of wood subjected to thermal loads, and the decrease of cross section of a wooden structural element. The European legislation on timber construction, Eurocode 5, proposes a simplification to determine the residual section of a wooden structural element in a fire situation. This paper objectives consist in a review of some researches in the field of variations, depending on the temperature, of the thermal properties of wood (specific heat, density and thermal conductivity); and in the construction of a few finite element models of timber structural elements affected by thermal loads according to ISO 834-1. The results were compared with a model based in Eurocode 5 and with an experimental test. As final result, at last, we propose a finite element model that simulates the behavior of the experimental tested element

Tratamiento quirúrgico-ortodóncico del canino superior incluido en posición vestibular

En el maxilar superior, el canino es el diente que se encuentra incluido con mayor frecuencia, después de los terceros molares. Se observa aproximadamente en un 2% de los pacientes que acuden a una consulta para tratamiento ortodóncico. Su ubicación es normalmente palatina, con una relación 2-3: I respecto a la localización vestibular o media. Para colocar este diente en una posición correcta dentro de la arcada debe realizarse en muchas ocasiones un tratamiento combinado ortodóncico­quirúrgico. Cuando el canino tiene una localización palatina, la técnica quirúrgica de elección suele ser una fenestración para hacer tracción extramucosa; pero cuando se ubica en posición vestibular, existen diversas opciones que dependen principalmente de la altura y de la cantidad de encía adherida que rodea al diente. Hemos realizado una revisión bibliográfica de los diversos abordajes quirúrgicos posibles ante un canino incluido por vestibular, sus indicaciones, ventajas e inconvenientes, y la ilustraremos con diversos casos tratados en nuestro servicio

Estado actual y perspectivas de las bibliotecas digitales latinas

En este trabajo, se hace una revisión de las bibliotecas electrónicas disponibles para profesionales de la Filología latina. Se parte de la base de que el uso de las Tecno- logías de la Información y las Comunicaciones (TIC) no puede ser considerado ajeno a nuestro normal desempeño, pero tampoco una moda más. Las herramientas deben servir para algo concreto, de donde que la evaluación de su utilidad sea un elemento básico del trabajo de cualquier campo científico. Tras una reflexión inicial acerca del concepto y lí- mites de las bibliotecas electrónicas, se hace un repaso por las principales, atendiendo so- bre todo a su facilidad de uso y a la utilidad de los materiales que proporciona

A comparative study of silver amalgam and compomer as retrograde filling materials in periapical surgery

Objective: A comparative study is made of the histological effects of silver amalgam versus compomer (Dyract®) 90 days after placement as retrograde filling materials in experimental animals. Method: Six Beagle dogs were used, with total pulpectomy and orthograde material filling followed by periapical surgery of the 6 upper and 6 lower incisors (for a total of 72 teeth). Thirty-six teeth corresponded to the right side and were filled with the control material (silver amalgam), while the 36 teeth on the left side were filled with the compomer study material (Dyract®). After three months the animals were sacrificed and the histological study was carried out, with evaluation of bone formation, inflammation, and the tissue in contact with the filler material. The results obtained were subjected to a descriptive and comparative statistical analysis (chi-square test). Results: The samples retrogradely filled with compomer showed significantly greater percentage inflammation (76.19% versus 26.66% in the control group). On the other hand, a large proportion of samples with root cement growth were found in the compomer group. Filler material expulsion was also significantly more common when compomer was used. Conclusions: the comparative study of the histological findings showed greater inflammation but also greater root cement growth in the compomer group versus the controls

A comparative study of silver amalgam and compomer as retrograde filling materials in periapical surgery

Objective: A comparative study is made of the histological effects of silver amalgam versus compomer (Dyract®) 90 days after placement as retrograde filling materials in experimental animals. Method: Six Beagle dogs were used, with total pulpectomy and orthograde material filling followed by periapical surgery of the 6 upper and 6 lower incisors (for a total of 72 teeth). Thirty-six teeth corresponded to the right side and were filled with the control material (silver amalgam), while the 36 teeth on the left side were filled with the compomer study material (Dyract®). After three months the animals were sacrificed and the histological study was carried out, with evaluation of bone formation, inflammation, and the tissue in contact with the filler material. The results obtained were subjected to a descriptive and comparative statistical analysis (chi-square test). Results: The samples retrogradely filled with compomer showed significantly greater percentage inflammation (76.19% versus 26.66% in the control group). On the other hand, a large proportion of samples with root cement growth were found in the compomer group. Filler material expulsion was also significantly more common when compomer was used. Conclusions: the comparative study of the histological findings showed greater inflammation but also greater root cement growth in the compomer group versus the control

Monografia histórico-descriptiva de la Real Parroquia de los Stos. Juanes de Valencia

Premi dels Jocs Florals del Rat PenatLocalització de l'original : Fundació AmatllerForma part del projecte: Biblioteca Digital d'Història de l'Art Hispànic (UAB)Monografia il·lustrada sobre l'església dels Sants Joans de València que fou premiada en les Jocs Florals de la Secció d'Arqueologia i Història de l'associació cultural valenciana de Lo Rat Penat el 1909.Monografia ilustrada sobre la iglesia de los Santos Juanes en Valencia que fue premiada en los Juegos Florales de la Sección de Arqueología e Historia de la asociación cultural valenciana de Lo Rat Penat en 1909.Illustrated monograph on the Santos Juanes church in Valencia. It was awarded in the Floral Games of the Archaeology and History section of the cultural society Lo Rat Penat in 1909

Autoimmune rheumatic diseases

The term autoimmune rheumatic diseases (ARDs) encompasses a heterogeneous group of conditions characterized by joint involvement along with a wide spectrum of systemic manifestations. The most common ARDs are rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Nevertheless, all these conditions share similar pathophysiological mechanisms [1, 2] and a common risk of developing a process of accelerated atherosclerosis [3]. In this regard, in this special issue J. Amaya-Amaya and colleagues discussed the mechanisms associated with the increased risk of cardiovascular disease (CVD) in patients with autoimmune diseases. These authors emphasize the relevance of the CVD in rheumatic conditions and its connection with inflammation and autoimmunity. They also highlight the need of a more aggressive management of these conditions, both of disease activity and classic cardiovascular risk factors. A good example of accelerated atherosclerosis in the setting of an ARD is SLE, in which endothelial dysfunction, an early step in the atherogenesis process, is observed before cardiovascular events can occur. With respect to this, A. Mak and N. Y. Kow performed a comprehensive review of the mechanisms that are involved in endothelial damage.These authors focused on the factors involved in endothelial damage and repair and, therefore, in the development of CVD in patients with SLE. They discussed the relevant role of factors such as type 1 interferon, proinflammatory cytokines, inflammatory cells, immune complexes, costimulatory molecules, neutrophils extracellular traps, lupus-related autoantibodies, oxidative stress, and dyslipidemia that along with the aberrant function of the endothelial progenitor cells lead to endothelial dysfunction and increased susceptibility to develop CVD in patients with SLE. Based on these lines of evidence, the authors’ claim is in favor of early intervention at the preclinical stage of atherogenesis in these patients

Selectively boron doped homoepitaxial diamond growth for power device applications

Diamond lateral growth is a powerful technique for the design and fabrication of diamond-based power electronic devices. Growth orientation affects the diamond deposition in terms of growth rate, surface roughness, and impurity incorporation. It has been shown that the finally grown surface of a patterned substrate can be predesigned based on the growth conditions. Thus, simultaneous growth along different surface orientations yields regions with different properties. In line with this, the incorporation of boron in a microwave plasma enhanced chemical vapor deposition laterally deposited epilayer over a mesa patterned {100}-oriented diamond substrate was studied by cathodoluminescence. It was observed that laterally oriented facets were highly boron doped in contrast to the {100}-oriented surfaces, which did not show any bound exciton emission, related to the doping. This study shows that, by designing the initial pattern and tuning the conditions, it is possible to drive a selective incorporation of boron into the grown layer

Implantes en pacientes VIH positivo. A propósito de tres casos

El aumento de la calidad y la esperanza de vida de los pacientes VIH-positivo, ha hecho que la solicitud de tratamiento estético dental se haya incrementado significativamente en estos pacientes, considerándose actualmente las prótesis implantosoportadas como una opción terapéutica válida. Se presentan 3 pacientes varones, VIH-positivo que acudieron a nuestro Servicio de Implantología Bucofacial, para valorar una posible rehabilitación implantosoportada. La evolución clínica de los pacientes había sido estable durante un periodo mínimo de 4 años. Se colocaron un total de 12 implantes (caso 1: 4 implantes Defcon®, 2 en maxilar superior y 2 en mandíbula; caso 2: 2 implantes ITI® en mandíbula; caso 3: 6 implantes Brånemark System® en maxilar superior), todos ellos bajo anestesia locorregional y siguiendo la técnica habitual. No se llevó a cabo ningún tipo de técnica de regeneración ósea guiada. No se presentaron complicaciones intra y/o postoperatorias. Tampoco se produjo ninguna alteración de los parámetros biológicos de control de la enfermedad de base tras la intervención quirúrgica. Los implantes han sido considerados como una opción de tratamiento en este tipo de pacientes pese a que su fiabilidad, no ha sido todavía establecida a largo plazo. A excepción de dos artículos (implante unitario inmediato y una rehabilitación bucal completa), ningún otro estudio ha sido publicado referente a la rehabilitación con implantes en pacientes VIH-positivo. En ambos artículos se corrobora la hipótesis que la cirugía bucal menor no aumenta el riesgo de infección locorregional en los pacientes VIH-positivo correctamente controlados, como evidenciamos en nuestros 3 casos. En el postoperatorio inmediato, no se observó ninguna disminución significativa del marcador CD4 ni de ningún otro parámetro biológico, tal como se describe en la literatura, obteniéndose una excelente curación de los tejidos blandos y duros

Autoimmune rheumatic diseases

"The term autoimmune rheumatic diseases (ARDs) encompasses a heterogeneous group of conditions characterized by joint involvement along with a wide spectrum of systemic manifestations. The most common ARDs are rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Nevertheless, all these conditions share similar pathophysiological mechanisms [1, 2] and a common risk of developing a process of accelerated atherosclerosis [3]. In this regard, in this special issue J. Amaya-Amaya and colleagues discussed the mechanisms associated with the increased risk of cardiovascular disease (CVD) in patients with autoimmune diseases. These authors emphasize the relevance of the CVD in rheumatic conditions and its connection with inflammation and autoimmunity. They also highlight the need of a more aggressive management of these conditions, both of disease activity and classic cardiovascular risk factors. A good example of accelerated atherosclerosis in the setting of an ARD is SLE, in which endothelial dysfunction, an early step in the atherogenesis process, is observed before cardiovascular events can occur. With respect to this, A. Mak and N. Y. Kow performed a comprehensive review of the mechanisms that are involved in endothelial damage.These authors focused on the factors involved in endothelial damage and repair and, therefore, in the development of CVD in patients with SLE. They discussed the relevant role of factors such as type 1 interferon, proinflammatory cytokines, inflammatory cells, immune complexes, costimulatory molecules, neutrophils extracellular traps, lupus-related autoantibodies, oxidative stress, and dyslipidemia that along with the aberrant function of the endothelial progenitor cells lead to endothelial dysfunction and increased susceptibility to develop CVD in patients with SLE. Based on these lines of evidence, the authors’ claim is in favor of early intervention at the preclinical stage of atherogenesis in these patients