Abstract Introduction Ongoing research in the use of electromagnetic stimulation as coadjuvant in fracture healing has led the authors to begin generating computer models in order to predict cellular growth changes when cells are electromagnetically stimulated. By generating these models, scientists will be able to better understand how electromagnetic fields affect cellular development. The experimental design integrated a cellular culture bioreactor along with an external magnetic stimulation system, which allowed for dermal models to be exposed to controlled magnetic fields. Methods Initially, it was necessary to analyze the static growth of Normal Human Skin Fibroblast (NHSF) cells when they were exposed to Extremely Low Frequency – Electromagnetic Fields (ELF-EMFs). Using optimal conditions for the NHSF culture, from stimulation signal to scaffolding material, we were able to perform the dynamic flow stimulation experiments. Results The following systems were developed: (1) a bioreactor aimed at cellular tissue culture, and (2) Helmholtz coils capable of generating stimulation signals for the cultured tissue. The authors were able to appreciate the quantified values of cellular density diluted in all the experiment samples that were taken and overall, the irradiated samples displayed an average increase of 53% higher cellular density for the same amount of initial cellular seeding when the cells were exposed to a 1 mT, 60 Hz magnetic field signal. Conclusion ELF-EMF’s indeed alter NHSF cell growth rates and it is the challenge of the authors to continue investigating what cellular mechanisms are altered when cells are exposed to ELF-EMF’s.

Introducción: El uso de estimulación electromagnética como coadyuvante en la consolidación de fracturas es controversial en la literatura médica. Métodos: Para este estudio, se diseñó y construyó un dispositivo capaz de generar un campo electromagnético. Tras confirmar su seguridad se asignaron pacientes aleatoriamente con fractura diafisaria de fémur a recibir terapia electromagnética o placebo. La estimulación inició a las seis semanas de la fractura, 1 h diaria, por ocho semanas consecutivas. Se construyeron 20 dispositivos, 10 reales y 10 dispositivos-placebo. Entre junio 2008 y octubre 2009, ingresaron 64 pacientes al estudio de dos instituciones y fueron seguidos durante 24 semanas. El promedio de edad de los pacientes fue de 30 años (rango 18-59) y 81% eran de sexo masculino. Resultados: La consolidación observada para el grupo con el dispositivo y el grupo placebo fue: en la semana 12, 75% vs. 58% (p =0.1); en la semana 18, 94% vs. 80% (p =0.15) y en la semana 24, 94% vs. 87% (p =0.43). Discusión: Este estudio muestra una tendencia a la consolidación más temprana al estar expuesto a un campo electromagnético frente a placebo. Una consolidación más temprana permite un apoyo precoz y, así, más rápida reincorporación al trabajo y a las actividades cotidianas.

Introduction: There is controversy in medical literature regarding the use of electromagnetic fields to promote bone healing. Methods: After designing and building devices capable of generating an electromagnetic field for this study, their safety was confirmed and the electromagnetic therapy was randomly allocated and compared to placebo in patients with fracture of the femoral diaphysis. Treatment began six weeks after the fracture and it was administered once a day, during 1 h, for eight consecutive weeks. Twenty devices were built, 10 of which were placebo-devices. Between June 2008 and October 2009, 64 patients were randomized in two different hospitals and were followed for 24 weeks. The mean age was 30 years (18-59) and 81% were males. Results: Healing observed at week 12 was 75% vs. 58% (p= 0.1); at week 18, it was 94% vs. 80% (p= 0.15); and at week 24, it was 94% vs. 87% (p= 0.43) for the device group and the placebo group, respectively. Discussion: This study suggests that an electromagnetic field stimulus can promote earlier bone healing compared to placebo in femoral diaphyseal fractures. Faster bone healing translates into sooner weight bearing, which - in turn - permits quicker return to normal daily activities.

El rápido crecimiento en las comunicaciones ámbricas ha llevado a la necesidad de evaluar de un modo eficaz la radiopropagación. Las densas áreas urbanas y los ambientes interiores tienden a ser entornos complejos que requieren una gran cantidad de áculos para ser modelados. En tales entornos, la radiopropagación de las ondas es un fenómeno extremadamente complicado y las técnicas de trazado de rayos han sido ampliamente usadas para analizar estos problemas. Sin embargo, el principal problema del algoritmo de trazado de rayos es su lentitud. Por lo tanto, el proceso del trazado de rayos se debe realizar con técnicas que mejoran la eficiencia de las simulaciones. En este artículo se presenta una nueva técnica de aceleración de trazado de rayos que combina las técnicas AZB y octree para la subdivisión del espacio. Esta nueva técnica se validó mediante mediciones de propagación en dos ambientes hospitalarios, encontrando que el máximo error entre los valores medidos y calculados fue inferior al 8%. La nueva técnica permitió reducir el tiempo de cálculo a la mitad comparado con la técnica AZB. Sin embargo, a medida que crece el número de interacciones que se evalúan, crece el tiempo computacional

The rapid growth in wireless communications has led to the need for an effective way to evaluate the radio propagation. Dense urban areas and indoor spaces tend to be complex environments that require a lot of obstacles to be modeled. In such environments, the radio propagation is an extremely complex phenomenon and ray tracing techniques have been widely used to analyze these problems. However, the main drawback of ray tracing algorithm is it slowness. Therefore, the ray tracing process should be performed using techniques that improve the efficiency of the computations. This paper presents a new ray tracing acceleration technique that combines AZB and octree techniques to subdivide the space. This new technique was validated by propagation measurements in two hospital environments and the maximum error encountered for measured and calculated values was below 8%. The new technique reduces the computation time by half in comparison to AZB technique. But, as the number of interactions increases, computational time increases as well

Neste trabalho, uma análise espectroscópica completa de UV-Vis, IR e RMN (¹H, 13C e DEPT) foi realizada para uma amostra de óleo vegetal FR3® usada como refrigerante dielétrico em um transformador de distribuição experimental. A mesma análise espectroscópica foi realizada para três amostras de óleo FR3® (i.e., com 4 meses de uso, 8 meses e 7 anos de uso), removidas de vários transformadores de distribuição operacional. A comparação entre os dados indicou que não ocorreram mudanças espectroscópicas significativas, e, portanto, não ocorreram mudanças estruturais aos óleos, pelo uso. Transformações químicas como hidrogenação catalítica e hidrólise foram realizadas à amostra de óleo FR3® e os produtos obtidos foram analisados por métodos espectroscópicos, a fim de recolher mais informações sobre o óleo FR3®. Testes de envelhecimento acelerado em laboratório também foram realizados para as três amostras de óleo FR3®, proporcionando informações interessantes sobre a estrutura dos produtos de degradação. Estas informações podem ser valiosas à busca de uma técnica baseada em espectroscopia para monitoramento do tempo de vida e desempenho deste óleo vegetal isolante.

In this work, a complete UV-Vis, IR and (¹H, 13C and DEPT) NMR spectroscopic analysis was performed for a FR3® vegetable oil sample used as dielectric coolant in an experimental distribution transformer. The same spectroscopic analysis was performed for three used FR3® oil samples (i.e., 4 months in use, 8 months in use and 7 years in use), removed from several operating distribution transformers. Comparison of the data indicated that no significant spectroscopic changes, and hence, no structural changes occurred to the oils by the use. Chemical transformations like catalytic hydrogenation (hardening) and hydrolysis were performed to the FR3® oil sample and the obtained products were analyzed by spectroscopic methods in order to collect further structural information about the FR3® oil. Accelerated aging tests in laboratory were also performed for three FR3® oil samples affording interesting information about the structure of the degradation products. These findings would be valuable to search for a spectroscopy-based technique for monitoring the life-time and performance of this insulating vegetable oil.