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Our objective was to use computational modeling to provide a full and comprehensible physical description of the electrical and thermal behavior during electroencephalography-guided radiofrequency thermocoagulation (SEEG-RF-TC), a minimally invasive procedure to destroy epileptic foci in the brain. We used the Finite Element Method to solve a coupled electrical- thermal problem and obtain the temperature distributions in the tissue for a constant power thermocoagulation. We found that 5 W provokes an impedance roll-off (abrupt increase) after approximately 10 s, and that this is related to temperatures of 100 ºC in the surroundings of the contacts. Due to the internal resistance associated with the wires of the electrode, self- heating provoked a temperature increase of up to 3.3 ºC throughout the device. Our findings should alert clinicians who are guided by impedance during SEEG-RF-TC regarding overheating associated with roll-off. The self-heating (approximately 3 ºC) occurring along the electrode should also be taken into account as it could provoke thermal side-effects.

La ablación cardiaca por radiofrecuencia (RF) es una terapia de gran relevancia para tratar las arritmias cardiacas. Con la RF se consigue calentar un tejido de forma muy precisa, y generar un daño irreversible él, impidiendo la activación de esas células, y permitiendo eliminar focos arrítmicos y aislar estructuras. El diseño y desarrollo de esta tecnología requiere realizar ensayos preclínicos. Frecuentemente, se emplean ensayos ex vivo con muestras de tejido biológico para determinar el tamaño y forma de las lesiones y las temperaturas alcanzadas. El objetivo de este estudio es averiguar si los sensores de temperatura posicionados en el interior del tejido durante dichos ensayos producen alguna perturbación. Se construyó un modelo computacional 3D incluyendo una porción de tejido cardiaco, y se analizaron las temperaturas alcanzadas. Se modelaron dos tipos de sensores de temperatura (termopares y fibra óptica) en distintas localizaciones. Mientras que las fibras ópticas apenas provocan perturbaciones (desviaciones menores de 0.6ºC), la presencia de los termopares altera de forma importante la medida (diferencias de hasta 9.78ºC). Sugerimos que la causa es el propio material metálico de los cables del termopar, que actúa como disipador térmico. Pese a todo, el tamaño y forma de la lesión inducida por RF no parece estar afectado por la presencia de cualquiera de los dos sensores.

Catchment urbanisation results in urban streams being exposed to a multitude of stressors. Notably, stressors originating from diffuse sources have received less attention than stressors originating from point sources. Here, advances related to diffuse urban stressors and their consequences for stream benthic communities are summarised by reviewing 92 articles. Based on the search criteria, the number of articles dealing with diffuse urban stressors in streams has been increasing, and most of them focused on North America, Europe, and China. Land use was the most common measure used to characterize diffuse stressor sources in urban streams (70.7 % of the articles characterised land use), and chemical stressors (inorganic nutrients, xenobiotics, metals, and water properties, including pH and conductivity) were more frequently reported than physical or biological stressors. A total of 53.3 % of the articles addressed the impact of urban stressors on macroinvertebrates, while 35.9 % focused on bacteria, 9.8 % on fungi, and 8.7 % on algae. Regarding ecosystem functions, almost half of the articles (43.5 %) addressed changes in community dynamics, 40.3 % addressed organic matter decomposition, and 33.9 % addressed nutrient cycling. When comparing urban and non-urban streams, the reviewed studies suggest that urbanisation negatively impacts the diversity of benthic organisms, leading to shifts in community composition. These changes imply functional degradation of streams. The results of the present review summarise the knowledge gained to date and identify its main gaps to help improve our understanding of urban streams.

Introduction: Nurses frequently face different events associated with stress, psychosocial factors, and other issues which have impacts on their mental health. Objective: To assess the correlation between psychological demand, work control, social support, psychological stress, and burnout dimensions (illusion for the activity, psychic wear, indolence, guilt), within a model of trajectories among Mexican nurses. Methodology: This is a transversal, observational, and analytical study conducted on a convenience sample of 357 nursing professionals from the state of Morelos, Mexico. Data were gathered using three questionnaires, the Perceived Stress Scale, the Job Content Questionnaire, y el Maslach Burnout Inventory. SPSS 19 and LISREL 8.3 were used to process and model the data. Results: Psychological Stress was specified as the mediating variable of the psychosocial factors and dimensions of burnout within the model of trajectories. Adjustment indexes were acceptable. High levels of social support, work control, and illusion for the activity were found. Moderate degrees of psychological demand and psychological stress were found. Low levels of psychic wear, indolence, and guilt were found. Conclusion: It is recommended to implement effective intervention strategies to maintain nursing personnel within low levels of psychological demand, high levels of work control, high levels of social support, and moderate levels of stress, all these in order to prevent the Syndrome of Burnout., Introdução: O pessoal de enfermagem se enfrenta cotidianamente a diferentes eventos associados ao estresse, fatores psicossociais e outros mecanismos que afetam sua saúde mental. Objetivo: Avaliar a correlação entre a demanda psicológica, o controle laboral, o apoio social, o estresse psicológico, e as dimensões e da Síndrome de Burnout (ilusão pelo trabalho, desgaste psíquico, indolência e culpa), em um modelo de trajetórias em enfermeiras mexicanas. Metodologia: Estudo transversal, observacional, analítico, conduzido em 357 profissionais de enfermagem de Morelos, México, selecionados por conveniência. Os dados foram coletados empregando três questionários, a Escala de Estresse Percebido, o Questionário do Conteúdo do Trabalho e o Questionário para a Avaliação da Síndrome de Burnout no Trabalho. Os programas SPSS 19 e LISREL 8.3 foram empregados para o processamento e modelagem dos dados. Resultados: No modelo de trajetórias, especificou-se como variável mediadora dos fatores psicossociais e das dimensões da Síndrome de Burnout no Trabalho (SQT), ao estresse psicológico. Os índices de ajuste foram aceitáveis. Encontraram-se altos níveis de apoio social, controle laboral e ilusão pelo trabalho; graus moderados de demanda psicológica e estresse psicológico; e baixos níveis de desgaste psíquico, indolência e culpa. Conclusão: Implicações para a disciplina, propõe-se implementar estratégias de intervenção efetivas para manter no pessoal de enfermagem baixos níveis de demandas psicológicas, altos níveis de controle laboral, altos níveis de apoio social, e níveis moderados de estresse, para prevenir, o SQT., Introducción: El personal de enfermería se enfrenta cotidianamente a diferentes eventos asociados al estrés, factores psicosociales y otros mecanismos que afectan su salud mental. Objetivo: Evaluar la correlación entre la demanda psicológica, el control laboral, el apoyo social, el estrés psicológico, y las dimensiones del Síndrome de Burnout (ilusión por el trabajo, desgaste psíquico, indolencia y culpa), en un modelo de trayectorias en enfermeras mexicanas. Metodología: Estudio transversal, observacional, analítico, conducido en 357 profesionales de enfermería de Morelos, México, seleccionados por conveniencia. Los datos fueron colectados empleando tres cuestionarios, la Escala de Estrés Percibido, el Cuestionario del Contenido del Trabajo y el Cuestionario para la Evaluación del Síndrome de Quemarse por el Trabajo. Los programas SPSS 19 y LISREL 8.3 fueron empleados para el procesamiento y modelaje de los datos. Resultados: En el modelo de trayectorias, se especificó como variable mediadora de los factores psicosociales y de las dimensiones del Síndrome de Quemarse por el Trabajo (SQT), al estrés psicológico. Los índices de ajuste fueron aceptables. Se encontraron altos niveles de apoyo social, control laboral e ilusión por el trabajo; grados moderados de demanda psicológica y estrés psicológico; y bajos niveles de desgaste psíquico, indolencia y culpa. Conclusión: Implicaciones para la disciplina, se propone implementar estrategias de intervención efectivas para mantener en el personal de enfermería bajos niveles de demandas psicológicas, altos niveles de control laboral, altos niveles de apoyo social, y niveles moderados de estrés, para prevenir, el SQT.