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Objective The structure of the semantic network is constructed and organized during childhood development. Previous publications have hypothesized that neurodegenerative diseases would lead to a disruption of this network reversing the steps acquired in childhood. Semantic Dementia (SD) is a subtype of frontotemporal lobe degeneration in which the main symptom is a specific loss of semantic memory. We aimed to describe the sequential acquisition of concepts in 3-8 years old children evaluated through the production of drawings and, in parallel, their progressive loss in SD patients. Methods 104 children between 40 and 96 months categorized into tertiles according to their age, 21 SD patients categorized into tertiles according to their score on a category fluency task and 34 healthy volunteers were asked to draw 12 items with, a priori, different age of acquisition and familiarity, belonging to four different semantic categories. We employed the drawings of the healthy volunteers to build a scoring scheme. We considered that a concept was acquired in children when 50% or more of its features were present in their drawings, and it was lost in patients when more than 50% were missing. Results Those concepts which the children were able to acquire earlier, according to our scoring scheme, tended to remain in patients with more advanced SD. While the items that children acquired later, were, in general, those that the SD patients lost at earlier disease stages. Conclusion The patterns of concept acquisition in children were the mirror image of the loss in patients with SD. Our study supports the hypothesis that the sequence of concept acquisition in childhood is reversed in SD patients.

The failure analysis of the rod-end bearing from an actuating cylinder used to open and close the left main landing gear inboard door by hydraulic pressure of an aircraft has been studied. The rod was manufactured with a quenched and tempered AISI 4130 steel and coated with cadmium. A chemical analysis of the rod-end bearing material was performed using a XRF equipment. To characterize the steel microstructure, metallographic samples were prepared to be inspected in an optical microscope. The grain size was obtained using a software according to the standard ASTM E112. The fractographic study was carried out or accomplished using a stereo microscope and a FE-SEM equipped with a microanalysis system by EDX. The macroscopic appearance of fracture surfaces indicated that cracking had initiated by multiple origins in the lubrication passage. The microfractographic analysis showed tear and transgranular cleavage/quasi-cleavage fracture mechanisms. Scanning electron microscopy indicated that cadmium metal was present in the steel material and on the fracture surfaces near the origin area. It was concluded that the failure of the rod resulted in a solid metal-induced embrittlement (SMIE) followed by tearing and transgranular cleavage/quasi-cleavage and a final catastrophic overload.

One flange of a spring belonging to an actuator drive that worked under torsion has been fractured. It is placed next to the electric motors whose mission is to move the drive manually through a hexagonal key. The whole equipment is an extensor-retraction actuator consisting in two electric motors that run a gear. This gear pulls a chain moving a telescopic beam. It was confirmed that there was no signs of anomalous working previous to the fracture. Some roughness requirements were mandatory in the first wire of the spring as well as both spring flanges, thus two springs (used and new) were compared. Several tests were performed in order to determine the cause of the fracture such as a chemical and mechanical characterization of the material, a fractographic analysis of the fracture surface, and the determination of the spring treatment state using metallographic and microscopic techniques. Additional observations were carried out in the other flange in order to detect possible defects. It was verified that the material corresponds to a 300 maraging steel type IV in a solubilization and ageing heat treatment state. The fracture surface presented fractographic characteristics of a typical progressive fracture. It was concluded that although the steel type and treatment state is correct, the roughness of specific zones is not well finished and, may have generated a crack that have nucleated in a notch of the first wire of the spring inner side surface. The crack may be produced by a pinned particle or any other surface defect that afterwards may propagate by a fatigue mechanism.

One of the six cylinders of an aircraft four-cycle motor was fractured in two pieces between the 13th–14th cooling fins. To determine the root cause of the fracture, it was necessary a preliminary observation of the whole motor to verify the state of valves, spark plugs, seats, and their disposition in order to determine a possible motor malfunction previous to the failure. Afterwards, a chemical and mechanical material characterization and a fracture surface fractographic study were carried out determining the heat treatment state using metallography and microscopy techniques. Observations of the external and inner cylinder surface were made to detect the possible presence of cracks or pitting. Some pitting were observed in the cylinder external wall. It was determined that material was a quenched and tempered steel, type AISI 4140, and the fracture was brittle presenting fractographic signs of a progressive fracture, concluding that the fracture was originated by a corrosion pit localized in the cylinder external wall that progressed by a fatigue mechanism.

Multiple fracture cases of fuel control pressure tubes from aircraft engines have been reported. The aim of the present study is to determine the cause of this tube fracture. The studied set was composed by the mentioned tube, a welded connecting pipe, where the fracture has been produced, and a union nut. The fracture has been produced in one most critical zones of the tube, in a region next to the supporting body of the union nut to the connector. A visual examination and with a stereo microscope of the tube fracture surface has been carried out in order to determine the macrofractographic features. The results revealed a plastic macrodeformation of the tube, a damaged surface and signs of a possible corrosion process. The material has been chemical, mechanical and microstructural characterized. The results confirmed that it was within specifications. Fracture surface was also inspected by scanning electron microscopy to determine the microfractographic characteristics in order to find out the failure mechanism involved in the fracture. Fatigue striations, which are typical from a progressive fracture by a fatigue mechanism, have been observed. The origin of the fracture has been placed in defects located in the outer wall of the tube, leading to a final overload fracture.

The aim of this work is the determination of the cause of a bolt fracture. The group was formed by a screw and a castellated self-braking nut with a plastic brake. Chemical, mechanical and microstructural material characterizations were carried out, fulfilling all material specifications. A microscopic observation revealed fatigue striations, which are typical signs of a progressive fracture. The fracture has been produced in the penultimate thread, one of the most critical zones of the screw. Hydrogen embrittlement also could have occurred, decreasing the fatigue resistance of the screw, but also its life of service.

Resumen Introduccion La nefritis tubulo-intersticial asociada al virus BK es una complicacion del trasplante renal. La presencia de inclusiones virales denominadas celulas de decoy en extensiones citologicas urinarias y los altos titulos de carga viral DNA en plasma, orina, y tejido renal, son marcadores de replicacion de virus BK. Objetivo Analisis de la citologia urinaria, para el diagnostico precoz de infeccion de poliomavirus en pacientes trasplantados renales. Material y metodo Estudio retrospectivo, prospectivo y analitico de 114 citologias urinarias y carga viral en orina (PCR) realizadas a 33 pacientes con trasplante renal en busca de infeccion por virus BK. Analisis morfometrico de los 4 tipos de inclusiones virales (celulas de Decoy) por infeccion por virus BK utilizando software de imagenes NIS-Elements Advanced Research en su version 3.0. Resultados La citologia urinaria es una prueba diagnostica de screening para la deteccion de las celulas de Decoy con una alta sensibilidad del 81,4% y una especificidad de tan solo el 22,6%. Los 4 patrones citomorfologicos de celulas de Decoy muestran una dispersion de area y de la longitud menor del 50% con respecto al valor medio, siendo menor en el tipo celular iv . Conclusion La probabilidad de que un paciente trasplantado renal e infectado por el virus BK tenga una citologia con presencia de inclusiones nucleares compatibles con celulas de Decoy es alta, aunque su especifidad como signo de replicacion de la infeccion por virus BK es baja. Los 4 patrones citomorfologicos de celulas de Decoy deben considerarse subgrupos celulares diferentes.

Resumen Diversos estudios muestran la baja utilizacion de los diagnosticos de enfermeria en el primer nivel de atencion sanitaria. Se realizo un estudio cualitativo mediante una tecnica de grupo de discusion, cuyo objetivo fue conocer la opinion de las enfermeras del area sanitaria de A Coruna sobre las causas de la baja utilizacion de los diagnosticos de enfermeria (DdE) en atencion primaria Se hicieron 2 grupos, uno formado por ex alumnos de la Escuela Universitaria de Enfermeria Juan Canalejo, titulados durante los cursos 1999/2000 y 2000/2001, que habian realizado sus practicas clinicas en distintos centros de salud, y otro compuesto por enfermeras de atencion primaria que desempenaban su actividad en diferentes centros de salud, con distintas formacion pregrado y vinculacion laboral Las opiniones identificadas, mediante analisis de contenido, se clasificaron segun las caracteristicas de los participantes (ex alumnos, profesionales) y segun 3 aspectos: utilizacion de los DdE, factores que influyen en la no utilizacion y estrategias para su implantacion Resultados La opinion de ambos grupos fue que los DdE no son de uso habitual Los ex alumnos pusieron de manifiesto los siguientes factores que influyen en la no utilizacion: algunos profesionales los consideran innecesarios, complejidad de la estructura y vocabulario, falta de formacion, deficiencia de recursos e interes personal del profesional. Los profesionales establecieron los siguientes factores: el modelo medico hegemonico, recursos humanos insuficientes, inmovilismo y falta de motivacion, convivencia de distintos modelos de atencion, heterogeneidad de los profesionales, incertidumbre en la efectividad de los DdE en la mejora de la salud de la poblacion Ambos grupos opinaban que la obligacion o imposicion “con o sin formacion” seria la estrategia mas adecuada para la implantacion de los DdE Discusion La falta de conocimientos no aparece como la causa principal de la no utilizacion de los DdE entre los profesionales, cuando si lo era en estudios previos La metodologia cualitativa permite identificar los factores relacionados con la no utilizacion de los DdE, no puestos de manifiesto hasta el momento, asi como sugerir las vias para su implantacion