Diploic venous system: radiological-anatomical correlation

El sistema venoso diploico se encuentra ubicado entre la tabla externa e interna de los huesos planos de la calvaria craneana. A pesar de tener más de 200 años de descripto, es escasa la referencia en la literatura anatómica y antropológica. Merece destacarse que estos canales pueden ser confundidos con trazos fracturarios en la evaluación radiológica del traumatismo encéfalocraneano. En este trabajo nos proponemos describir las principales variantes anatómicas del sistema venoso diploico y determinar su distribución topográfica. Para ello realizamos un estudio descriptivo de corte transversal con una muestra de cráneos humanos (n=108), los cuales fueron transiluminados mediante introducción de fuente lumínica por el foramen magno. También se analizaron placas radiográficas de cráneo de perfil (n=60), discriminando topográficamente la ubicación de dichas venas. Se encontraron 5 patrones de distribución diferentes y un sexto como patrón indeterminado. Se determinó el porcentaje de hallazgo de venas diploicas según regiones. Lo obtenido se contrastó con la literatura clásica, llegando a la conclusión de la importancia que adquiere el conocimiento de estos patrones ante el diagnóstico diferencial de un trazo radiolúcido en una placa radiográfica de cráneo ante un traumatismo encéfalocraneano.The diploic venous system is located between the outer and inner table of the flat bones of the skull calvaria. Despite the fact that it has been described over 200 years ago, there is little reference on the matter in anatomical and anthropological literature. It is remarkable that these channels can be confused with fractures in the radiologic evaluation of head trauma. This study describes the main anatomical variants of the diploic venous system and illustrates their topographic distribution. In order to achieve this goal, a cross sectional study was conducted utilizing a sample of human skulls (n=108), which were transilluminated by introducing a light source through the foramen magnum. In addition, lateral skull radiographs (n=64) were analyzed, as means of discriminating the topographical location of the veins. Hence, 5 different distribution patterns were discovered, as well as a sixth undetermined pattern. The probability of finding diploic veins in each region was determined, and the results were compared to the theoretical framework. As a conclusion, it can be said that the learning of these patterns and becoming familiarized with their anatomic variants is of significant importance when considering differential diagnosis of a radiolucent line on a skull which has undergone head trauma.Sociedad de Ciencias Morfológicas de La Plat

Diploic venous system: radiological-anatomical correlation

El sistema venoso diploico se encuentra ubicado entre la tabla externa e interna de los huesos planos de la calvaria craneana. A pesar de tener más de 200 años de descripto, es escasa la referencia en la literatura anatómica y antropológica. Merece destacarse que estos canales pueden ser confundidos con trazos fracturarios en la evaluación radiológica del traumatismo encéfalocraneano. En este trabajo nos proponemos describir las principales variantes anatómicas del sistema venoso diploico y determinar su distribución topográfica. Para ello realizamos un estudio descriptivo de corte transversal con una muestra de cráneos humanos (n=108), los cuales fueron transiluminados mediante introducción de fuente lumínica por el foramen magno. También se analizaron placas radiográficas de cráneo de perfil (n=60), discriminando topográficamente la ubicación de dichas venas. Se encontraron 5 patrones de distribución diferentes y un sexto como patrón indeterminado. Se determinó el porcentaje de hallazgo de venas diploicas según regiones. Lo obtenido se contrastó con la literatura clásica, llegando a la conclusión de la importancia que adquiere el conocimiento de estos patrones ante el diagnóstico diferencial de un trazo radiolúcido en una placa radiográfica de cráneo ante un traumatismo encéfalocraneano.The diploic venous system is located between the outer and inner table of the flat bones of the skull calvaria. Despite the fact that it has been described over 200 years ago, there is little reference on the matter in anatomical and anthropological literature. It is remarkable that these channels can be confused with fractures in the radiologic evaluation of head trauma. This study describes the main anatomical variants of the diploic venous system and illustrates their topographic distribution. In order to achieve this goal, a cross sectional study was conducted utilizing a sample of human skulls (n=108), which were transilluminated by introducing a light source through the foramen magnum. In addition, lateral skull radiographs (n=64) were analyzed, as means of discriminating the topographical location of the veins. Hence, 5 different distribution patterns were discovered, as well as a sixth undetermined pattern. The probability of finding diploic veins in each region was determined, and the results were compared to the theoretical framework. As a conclusion, it can be said that the learning of these patterns and becoming familiarized with their anatomic variants is of significant importance when considering differential diagnosis of a radiolucent line on a skull which has undergone head trauma.Sociedad de Ciencias Morfológicas de La Plat

Density Functional Theory Analysis of Dichloromethane and Hydrogen Interaction with Pd Clusters: First Step to Simulate Catalytic Hydrodechlorination

We are grateful to the Spanish “Ministerio de Ciencia e Innovación” and “Comunidad de Madrid” forfinancial support(CTQ2008-04751, CTQ2008-05641, and S2009/PPQ-1545).We are also very grateful to“Centro de Computaci on Científicade la Universidad Autonoma de Madrid” for computational facilities.A density functional theory (DFT) analysis has been conducted for the gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) with palladium catalyst to achieve a better knowledge of the reaction mechanism involved in the HDC process, which constitutes an emerging technology for the treatment of organochlorinated contaminants. The computational study included the effect of size, oxidation state, and spin configuration of Pd cluster on the adsorption of H2 and DCM reactants on the catalyst surface. Calculations described the activation of H2 by Pd clusters through a dissociative adsorption with low enthalpy values. In addition, partially and fully dissociated DCM intermediates on Pd surface were predicted by DFT calculations. Remarkably, the dissociative adsorption of DCM on Pd active sites occurs via the scission of C–Cl bonds, promoted by the formation of C–Pd linkages, implying high adsorption enthalpy. The computational results showed that DCM can be also molecularly adsorbed on both zerovalent and electrodeficient Pd species. However, the nondissociative adsorption of DCM over electrodeficient Pd cluster is remarkably favored in energy, with adsorption enthalpies (∼−50 kcal/mol) corresponding to chemisorption. Current theoretical evidence explained the deactivation of Pd/AC catalyst as a consequence of the selective poisoning of electrodeficient Pd active centers by chlorinated hydrocarbons, in good agreement with our previous experimental findings.Ministerio de Ciencia e Innovación (España)Comunidad de MadridDepto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEpu