Problems when generating virtual models representing real objects: Hondarribia walls

[EN] This paper is based in the following project:

Estudio de la precisión de varios modelos de turbulencia en la aplicación a perfiles aerodinámicos

[ES]El objetivo principal de este proyecto se centra en modelizar correctamente la capa límite sobre el perfil alar donde se produce la transición del régimen laminar al régimen transitorio. Como objetivo secundario se encuentra el afianzamiento de las bases teóricas de mecánica de fluidos obtenidas en la escuela y la adquisición de más conocimientos relacionados con la aerodinámica, concretamente con la capa límite. En una primera parte se tratarán los conceptos generales de los perfiles alares y se hará una breve introducción a los distintos tipos de mallado existentes. También se explicará el concepto de capa límite y todo lo relacionado con ella. A continuación, se establecerán los criterios de selección del modelo de turbulencia más adecuado y se mostrarán los resultados obtenidos de los distintos tipos de modelos de turbulencia anteriormente mencionados. Una vez seleccionado un modelo de turbulencia se profundizará en su estudio, aplicándolo a varios perfiles NACA. Se analizarán los resultados obtenidos y los errores y se buscarán posibles soluciones. Finalmente, se procederá a sacar las conclusiones del modelo escogido y se comparará con una serie de ensayos experimentales con objeto de poder validarlo.

PICC vs Catéter central insertado en vena subclavia en pacientes críticos

[Es]Introducción: actualmente, en servicios como UCIs, quirófanos y Urgencias cada vez es más común el empleo de CVCS y PICC. Ambos están asociados a graves complicaciones como CLABSI, TVP, EP, arritmia, etc. Dado que la enfermería juega un papel importante tanto en la inserción de estos dispositivos, como en el mantenimiento y prevención de las adversidades, es necesario poseer los conocimientos y habilidades adecuados para su afrontamiento. Objetivo y metodología: determinar cuál de los dos supone menor riesgo de complicaciones en pacientes críticos mediante la evidencia científica y utilizando la EBE. Para ello se ha realizado una revisión bibliográfica de estudios encontrados en bases de datos como Pubmed, Cochrane y Cinhal mediante la combinación de términos MeSH y palabras clave con operadores booleanos. Resultados y discusión: se han incluido en total 13 publicaciones (6 RS, 4 estudios de cohorte, 1 ECA y 2 GPC), de las cuales 3 poseen calidad alta, 3 media y 5 baja. Tanto los PICC como los CVCS implican diversas complicaciones, divididas en infecciosas, trombo-embolicas y mecánicas/otras. Existe insuficiente evidencia científica y gran heterogeneidad entre los artículos, lo que dificulta su extrapolación. Conclusiones: en pacientes críticos los PICC poseen mayor riesgo de TVP, los CVCS de complicaciones mecánicas, y ambos presentan tasas similares de CLABSI. Es importante escoger de forma individualizada el catéter a implantar, estimando los riesgos-beneficios de cada uno. Los cuidados preventivos son fundamentales en la reducción de estas contingencias. Son necesarios más estudios prospectivos comparativos.

Pio del Rio Hortega and the discovery of the oligodendrocytes

Rio del Rio Hortega (1882-1945) discovered microglia and oligodendrocytes (OLGs), and after Ramon y Cajal, was the most prominent figure of the Spanish school of neurology. He began his scientific career with Nicolas Achucarro from whom he learned the use of metallic impregnation techniques suitable to study non-neuronal cells. Later on, he joined Cajal's laboratory. and Subsequently, he created his own group, where he continued to develop other innovative modifications of silver staining methods that revolutionized the study of glial cells a century ago. He was also interested in neuropathology and became a leading authority on Central Nervous System (CNS) tumors. In parallel to this clinical activity, del Rio Hortega rendered the first systematic description of a major polymorphism present in a subtype of macroglial cells that he named as oligodendroglia and later OLGs. He established their ectodermal origin and suggested that they built the myelin sheath of CNS axons, just as Schwann cells did in the periphery. Notably, he also suggested the trophic role of OLGs for neuronal functionality, an idea that has been substantiated in the last few years. Del Rio Hortega became internationally recognized and established an important neurohistological school with outstanding pupils from Spain and abroad, which nearly disappeared after his exile due to the Spanish civil war. Yet, the difficulty of metal impregnation methods and their variability in results, delayed for some decades the confirmation of his great insights into oligodendrocyte biology until the development of electron microscopy and immunohistochemistry. This review aims at summarizing the pioneer and essential contributions of del Rio Hortega to the current knowledge of oligodendrocyte structure and function, and to provide a hint of the scientific personality of this extraordinary and insufficiently recognized man.

From the Cajal alumni Achucarro and Rio-Hortega to the rediscovery of never-resting microglia

Under the guidance of Ramon y Cajal, a plethora of students flourished and began to apply his silver impregnation methods to study brain cells other than neurons: the neuroglia. In the first decades of the twentieth century, Nicolas Achucarro was one of the first researchers to visualize the brain cells with phagocytic capacity that we know today as microglia. Later, his pupil Pio del Rio-Hortega developed modifications of Achucarro's methods and was able to specifically observe the fine morphological intricacies of microglia. These findings contradicted Cajal's own views on cells that he thought belonged to the same class as oligodendroglia (the so called "third element" of the nervous system), leading to a long-standing discussion. It was only in 1924 that Rio-Hortega's observations prevailed worldwide, thus recognizing microglia as a unique cell type. This late landing in the Neuroscience arena still has repercussions in the twenty first century, as microglia remain one of the least understood cell populations of the healthy brain. For decades, microglia in normal, physiological conditions in the adult brain were considered to be merely "resting," and their contribution as "activated" cells to the neuroinflammatory response in pathological conditions mostly detrimental. It was not until microglia were imaged in real time in the intact brain using two-photon in vivo imaging that the extreme motility of their fine processes was revealed. These findings led to a conceptual revolution in the field: "resting" microglia are constantly surveying the brain parenchyma in normal physiological conditions. Today, following Cajal's school of thought, structural and functional investigations of microglial morphology, dynamics, and relationships with neurons and other glial cells are experiencing a renaissance and we stand at the brink of discovering new roles for these unique immune cells in the healthy brain, an essential step to understand their causal relationship to diseases.

Energetics and Structural Characterization of the large-scale Functional Motion of Adenylate Kinase

Adenylate Kinase (AK) is a signal transducing protein that regulates cellular energy homeostasis balancing between different conformations. An alteration of its activity can lead to severe pathologies such as heart failure, cancer and neurodegenerative diseases. A comprehensive elucidation of the large-scale conformational motions that rule the functional mechanism of this enzyme is of great value to guide rationally the development of new medications. Here using a metadynamics-based computational protocol we elucidate the thermodynamics and structural properties underlying the AK functional transitions. The free energy estimation of the conformational motions of the enzyme allows characterizing the sequence of events that regulate its action. We reveal the atomistic details of the most relevant enzyme states, identifying residues such as Arg119 and Lys13, which play a key role during the conformational transitions and represent druggable spots to design enzyme inhibitors. Our study offers tools that open new areas of investigation on large-scale motion in proteins.