Facetas de Cerec

Al moderno sistema de las facetas de porcelana, para la restauración de las caras labiales de los dientes, se le añade la variación técnica consistente en su realización mediante el sistema CAD-CAM. Se describe la técnica y sus ventajas

A parameterization of flow separation over subaqueous dunes

Flow separation plays a key role in the development of dunes, and modeling the complicated flow behavior inside the flow separation zone requires much computational effort. To make a first step toward modeling dune development at reasonable temporal and spatial scales, a parameterization of the shape of the flow separation zone over two-dimensional dunes is proposed herein, in order to avoid modeling the complex flow inside the flow separation zone. Flow separation behind dunes, with an angle-of-repose slip face, is characterized by a large circulating leeside eddy, where a separation streamline forms the upper boundary of the recirculating eddy. Experimental data of turbulent flow over two-dimensional subaqueous bed forms are used to parameterize this separation streamline. The bed forms have various heights and height to length ratios, and a wide range of flow conditions is analyzed. This paper shows that the shape of the flow separation zone can be approximated by a third-order polynomial as a function of the distance away from the flow separation point. The coefficients of the polynomial can be estimated, independent of flow conditions, on the basis of bed form shape at the flow separation point and a constant angle of the separation streamline at the flow reattachment point. \ud \u

Perimolisis

La perimolisis es un tipo de erosión en la que el agente químico implicado es el ácido de origen gástrico. Este refluye a la boca, bien por el vómito o por la regurgitación los cuales pueden darse por distintos trastornos, entre ellos destacan la anorexia y la bulimia nerviosa. La perimolisis presenta una clínica característica que facilita su diagnóstico, sin embargo es obligado el diagnóstico diferencial con otras causas de pérdida de tejidos dentales duros. El tratamiento rehabilitadar con prótesis fija debe posponerse a que el vómito o la regurgitación hayan remitido significativamente

El problema de las nauseas en el tratamiento protético

En condiciones normales, las nauseas son una respuesta refleja como mecanismo de defensa para evitar la entrada de cuerpos extraños en la tráquea. En algunos pacientes, la reacción a cualquier estímulo nauseoso es muy exagerada e incontrolable; lo que puede dificultar nuestro tratamiento profesional. La falta de experiencia y un limitado conocimiento por parte del profesional sobre el manejo de las nauseas, puede crear inseguridad al paciente sobre el tratamiento odontológico a realizar y una ansiedad al profesional hacia los pacientes que presentan este problema. Ante un paciente con una severa reacción a las nauseas, el profesional debe realizar una completa historia médica, una correcta exploración bucal valorando la sensibilidad de las áreas del trigémino y conversar con el paciente, a fin de recoger la máxima información para conocer la causa o causas que provocan el problema, consiguiendo así, superar el reflejo nauseoso

Spherical perspective

We survey the present state of spherical perspective, regarding both mathematical structure and drawing practice, with a view to applications in the visual arts. We define a spherical perspective as the entailment of a conical anamorphosis with a compact flattening of the visual sphere. We examine a general framework for solving spherical perspectives, exemplified with the azimuthal equidistant (“fisheye”) and equirectangular cases. We consider the relation between spherical and curvilinear perspectives. We briefly discuss computer renderings but focus on methods adapted to freehand sketching or technical drawing with simple instruments such as ruler and compass. We discuss how handmade spherical perspective drawings can generate immersive anamorphoses, which can be rendered as virtual reality panoramas, leading to hybrid visual creations that bridge the gap between traditional drawing and digital environments.info:eu-repo/semantics/publishedVersio

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

La conservazione preventiva del patrimonio librario come possibile alternativa al restauro tradizionale

The present paper focuses on the close relation between library collections and their preservation environment, aiming, in particular, at highlighting the importance of promoting and sustaining the monitoring. The paper proposes some simple and ready-to-use technologies – smart monitoring – to prevent future damages

Prótesis completa: montaje de dientes de acuerdo con los parámetros biológicos recogidos con rodetes de resina

Las cubetas de resina que incorporan los parámetros biológicos sirven al laboratorio de guía para el montaje de dientes pues en los rodetes se halla toda la información necesaria. Además permiten al clínico comprobar si el laboratorio ha transferido correctamente todos los parámetros