Abstract Several fields of research such as medicine, robotics, sports, informatics, etc., require the analysis of human movement. Traditional systems for acquisition and analysis of human movement data are based on video cameras or active sensors. However, those systems are limited to high-resource settings. Wearable devices allow monitoring subjects outside typical clinical or research environments. Here, we present an open source low-cost wireless sensor system for acquisition of human movement data. Our system consists of two main parts: a server that stores data and, one or more wearable sensor modules that collect movement data through Inertial Measurement Units (IMUs) and transmit them wirelessly to the server. As a proof of concept, we measured human gait activity. Our results show that our system with IMUs can acquire quantifiable movement data. Characteristics such as open source code and its low-cost, make our system a viable alternative for clinical or research.

The conditions of petroleum extraction may allow asphaltenes to precipitate, causing deposition that clogs wells, pipes and equipment, consequently reducing productivity. In this work, the solubility parameters and precipitation onset of polar fractions of heavy crudes from Brazilian fields were estimated using a simplified system of n-heptane/toluene mixtures. Asphaltenes were extracted by two different methods with regard to pressure and temperature. The samples were physically and chemically characterized, and both density (1053-1159 kg m-3) and molecular weight (1176-5316 g mol-1) were estimated based on the density of diluted asphaltenes in toluene solutions. The solubility of those fractions was studied as well as their solubility parameter (ca. 19-23 MPa0.5) based on regular solution theory, Flory-Hüggins theory and empirical correlation. The influence of asphaltene concentration (between 0.5 and 5.0 g L-1) on the solubility parameter and precipitation onset was studied, and a strong linear correlation between them was not found.

O parâmetro de solubilidade (δ) de uma molécula é extremamente importante, visto que novas moléculas são frequentemente desenvolvidas para serem aplicadas em sistemas líquidos. Neste trabalho, nós buscamos técnicas alternativas simples e confiáveis para determinar δ de moléculas de baixa e alta massa molar. Pireno, fenantreno e naftaleno tiveram seus δ determinados por microcalorimetria (µDSC), ultravioleta (UV) e calorimetria (DSC). Resultados de UV foram similares àqueles obtidos por DSC e àqueles citados na literatura. Amostras de poliestireno e poliestireno sulfonado tiveram seus δ determinados por UV, µDSC e viscosidade intrínseca ([η]). Os resultados de [η] foram similares àqueles obtidos por UV. Procedimento de UV foi relativamente simples, de fácil operação e confiável para determinação de δ de moléculas de ampla faixa de massa molar, podendo ser utilizado no desenvolvimento de novas moléculas. O procedimento utilizando μDSC ainda requer alguns ajustes a fim de torná-lo mais preciso do que [η].

The solubility parameter (δ) of a molecule is extremely important, since that new molecules are frequently developed to be applied in liquid systems. In this work, we looked for simple and reliable alternative techniques to determine δ of low and high molecular weight molecules. Pyrene, phenanthrene and naphthalene had their δ determined by microcalorimetry (µDSC), ultraviolet (UV) and calorimetry (DSC). UV results were similar to those obtained by DSC and to those cited in the literature. Polystyrene and sulfonated polystyrene samples had their δ determined by UV, µDSC and intrinsic viscosity ([η]). The [η] results were similar to those obtained by UV. UV procedure was relatively simple, easy operation and reliable for determining δ of molecules in a wide range of molar mass, can be used when developing new molecules. The µDSC procedure still requires some adjustments to become more accurate than [η] procedure.

Foi realizado um estudo para investigar a interação entre asfaltenos (em soluções de tolueno) e resinas (em soluções de n-heptano). Para entender melhor o tipo de interação entre essas frações, quantificou-se o consumo de resina quando asfaltenos (dissolvidos em tolueno) foram precipitados com uma solução de n-heptano contendo resina. Os resultados indicaram que a precipitação de asfaltenos ocorre juntamente com a redução na concentração de resina. Os perfis das isotermas de ligação indicaram que a saturação ocorreu em um caso, em quanto que o efeito cooperativo com posterior platô inicial foi observado para duas outras amostras. Estes resultados confirmaram a hipótese de que resinas podem adsorver em asfaltenos, mas não podem evitar floculação e precipitação de asfaltenos. Além disso, resultados de microcalorimetria sugeriram que a resina e asfalteno interagem por forças fracas de van der Waals. Estes resultados estão em contraste com a escola de pensamento predominante desde a década de 1940 que advoga que as resinas podem peptizar e estabilizar asfaltenos.

A study was carried out to investigate the interaction between asphaltenes (in toluene solutions) and resins (in n-heptane solutions). To better understand the type of interaction between these fractions, it was quantified the resin uptake when asphaltenes (dissolved in toluene) were precipitated by a resin-containing n-heptane solution. These results indicated the asphaltene precipitation occurs together with a reduction in the resin concentration. The binding isotherm profiles indicated that saturation occurred in one case, while collective association following an initial plateau was observed for the other two samples. These results confirmed the hypothesis that resins can adsorb on asphaltenes but cannot prevent asphaltenes from flocculating and precipitating. Furthermore, microcalorimetric results suggested that the resin and asphaltene interact by weak van der Waals forces. These results are in stark contrast with the school of thought prevalent since the 1940s that resins can peptize and stabilize asphaltenes.

The structure of the various asphaltenic subfractions found in crude oil was evaluated. For this purpose, C5 asphaltenes were extracted from an asphaltic residue using n-pentane as the flocculant solvent. The different subfractions were isolated from the C5 asphaltenes by the difference in solubility in different solvents. These were characterized by infrared spectroscopy, nuclear magnetic resonance, X-ray fluorescence, elementary analysis and mass spectrometry. The results confirmed that the subfractions extracted with higher alkanes had greater aromaticity and molar mass. However, small solubility variations between the subfractions were attributed mainly to the variation in the concentrations of cyclical hydrocarbon compounds and metals.

Vascular etiology is present in up to 60% of the patients with erectile dysfunction (ED). Both small vessel disease, such as that in diabetes mellitus, and arteriosclerosis of bigger size arteries, as in hypertension, cause arterial insufficiency and erectile dysfunction. Tobacco smoking alters the arterial hemodynamics in the penis, causing erectile dysfunction in a high percentage of advanced age smokers: pelvic arteries fibrosis and stenosis accelerates the existing arteriosclerosis. Venous occlusive dysfunction may be due to the decrease of corpora cavernosa compliance or tunica albuginea inherent anomalies. Vascular endothelial growth factor may play a role in the modulation of vascularization of the normal penile architecture. Various events, all of them important, may cause erectile dysfunction. Moreover, no cause can participate independently. A cascade of situations (including psychological factors as well as organic) may lead to erectile dysfunction. A continuous understanding of organic causes of erectile dysfunction will allow physicians to discover treatments for their correction, as well as to give confidence to the patient.

La etiología vascular de la disfunción eréctil está presente en el 60% de los pacientes con DE. La enfermedad de pequeños vasos, como en la diabetes, y la arteriosclerosis de arterias de mayor tamaño, como en la hipertensión, causa insuficiencia arterial y disfunción eréctil. El tabaco altera la hemodinámica arterial del pene, causando disfunción eréctil en un alto porcentaje de fumadores de edad avanzada: la fibrosis y estenosis de las arterias pélvicas acelera la arteriosclerosis existente. La disfunción venoclusiva puede deberse a la disminución de la distensibilidad de cuerpos cavernosos o anormalidades inherentes en la albugínea. El factor de crecimiento vascular endotelial puede desempeñar un papel en la modulación de la vascularización de la arquitectura normal del pene. Distintos acontecimientos, todos ellos importantes, pueden causar disfunción eréctil. Además, ninguna causa puede participar de forma independiente. Una cascada de situaciones (incluidos los factores psicológicos, así como los orgánicos) pueden llevar a la disfunción eréctil. Una comprensión continuada de las causas orgánicas de la disfunción eréctil permitirá al médico descubrir tratamientos para su corrección, así como proporcionar seguridad al paciente.

The objective of this work was to use the high-pressure homogenizer (HPH) to prepare stable oil/water nanoemulsions presenting narrow particle size distribution. The dispersions were prepared using nonionic surfactants based on ethoxylated ether. The size and distribution of the droplets formed, along with their stability, were determined in a Zetasizer Nano ZS particle size analyzer. The stability and the droplet size distribution in these systems do not present the significant differences with the increase of the processing pressure in the HPH). The processing time can promote the biggest dispersion in the size of particles, thus reducing its stability.

Objectives: To share our experience performing laparoscopic pyeloplasty and our contributions to this surgery. Methods: Between March 2004 and January 2006 we have performed 12 laparoscopic pyeloplasties in 12 patients. We modified our technique as we found difficulties during operations. By the only modification of patient position we have achieved a significant improve in our technique. Results: We describe how we performed the operation in the first cases and how we do it today, with the new position. We also describe the advantages observed. Conclusions: With our technique we achieve an important surgical time reduction, improvements in safety and reduction of surgical complications.

Objetivo: Nuestra intención con el presente artículo pretende compartir nuestra experiencia en relación con la realización de la pieloplastia laparoscópica y nuestras aportaciones en este sentido. Métodos: Hemos realizado 12 pielopastias laparoscópicas a otros tantos pacientes entre marzo del 2004 y enero 2006. A lo largo de nuestra serie hemos ido codificando la técnica quirúrgica a medida que nos hemos ido encontrando con dificultades durante la realización de la misma. Mediante la única modificación del posicionamiento del paciente hemos logrado una importante mejora en nuestra técnica. Resultados: Describimos en este artículo como realizábamos la intervención en nuestros primeros casos y de que forma estamos realizándola en este momento, gracias al nuevo posicionamiento. Asímismo damos cuenta de cuales son las ventajas que apreciamos. Conclusiones: Con nuestra técnica logramos una importante reducción en el tiempo quirúrgico, mejoras en cuanto a seguridad de la técnica y reducción de las complicaciones quirúrgicas.

The treatment of ureteropyelic junction (UPJ) obstruction offers a perfect sketch of the parallel evolution of the availability of technology and changes in surgical proceedings. From the open Anderson-Hynes pyeloplasty, passing through percutaneous or retrograde endopyelothomy with various instruments, to the laparoscopic approach, technology and human talent have found a field for development in this reconstructive procedure. Robotic surgery is young and starts to define its role in urology surgery. There are established procedures such as radical prostatectomy; it remains to be established what operations will benefit from the robotic technology, so results are under continuous evaluation. The non stopping advance of computer technology guarantees future achievements of robotic technology. The objective is to achieve that surgeons could perform difficult surgical procedures with a level of accuracy and clinical results that would be difficult to achieve with conventional methods. We analyze the technical features, results and comparative studies of the robotic pyeloplasty from the medical literature. Robotic surgery has demonstrated its usefulness in the performance of pyeloplasties, with good results in primary and secondary UPJ stenosis in children and adults, in various aetiologies. Robotics enables to diminish the difficulties of intracorporeal suture and the learning curve for surgeons without laparoscopic experience. Nevertheless, although initial clinical experience with robotic pyeloplasty is favourable, continuous evaluation of results is necessary to determine if the surgical procedure is as effective in the long-term as laparoscopic and open pyeloplasty.

El tratamiento de la estenosis de la unión pieloureteral nos ofrece un boceto exquisito de la evolución paralela entre la disponibilidad tecnológica y los cambios acontecidos en el proceder quirúrgico. Desde la pieloplastia abierta de Anderson-Hynes, pasando por la endopielotomía percutánea o retrógrada con distintos dispositivos; hasta llegar al abordaje laparoscópico, la tecnología y el ingenio humano han encontrado en este proceder reconstructivo un interesante escenario de desarrollo. La cirugía robótica se encuentra en su adolescencia y comienza a definir su papel en la cirugía urológica. Existen procedimientos asentados como la prostatectomía radical, resta por definir que tipo de intervenciones se van a beneficiar de la tecnología robótica, por ello los resultados están en continua evaluación. El avance imparable de la tecnología informática garantiza los futuros logros de la tecnología robótica. El objetivo es conseguir que el cirujano pueda realizar procedimientos quirúrgicos difíciles con un nivel de precisión y unos resultados clínicos difícilmente alcanzables con los métodos convencionales. Se analizan aspectos técnicos, resultados y estudios comparativos de la pieloplastia robótica en la literatura. La cirugía robótica ha demostrado su utilidad para realizar con buenos resultados la técnica de la pieloplastia en estenosis primarias y secundarias, en niños y adultos y en diferentes etiologías. La robótica permite disminuir las dificultades de la sutura intracorpórea y la curva de aprendizaje para cirujanos no habituados a la laparoscopia. No obstante, aunque la experiencia clínica inicial con la pieloplastia robótica es favorable, se hace necesaria una evaluación continua de los resultados para determinar si este proceder es tan eficaz a largo plazo como lo son la pieloplastia abierta y laparoscópica.

In this work, it was studied the behavior of the nonionic surfactant aqueous solutions, containing or not a hydrotropic agent, by resonance magnetic nuclear (NMR). We have studied monofunctional diblock copolymers of poly(propylene oxide-ethylene oxide) (R-PPO-PEO-OH, where R length is linear C4) as nonionic surfactant and sodium p-toluenesulfonate (NaPTS) as hydrotropic agent. The critical micelle concentration (CMC) of the aqueous copolymer solution was obtained from ¹H-NMR. The preliminary study of the interaction between the copolymer, under the unimer and micelle forms, and the hydrotrope, in aqueous solutions, was evaluated by ¹H-NMR and 13C-NMR.

O comportamento de sistemas aquosos contendo copolímeros dibloco monofuncionais de poli(óxido de etileno)-poli(óxido de propileno), bloqueados em uma das extremidades da cadeia com segmento hidrocarbônico linear, foi avaliado através de calorimetria exploratória diferencial (DSC). Transições endotérmicas foram observadas no aquecimento das soluções dos copolímeros e as temperaturas iniciais destas transições estão de acordo com os pontos de turvação dos copolímeros estudados. Nas curvas de resfriamento, são observadas duas transições, e quanto mais rápido é resfriada a solução de copolímero, melhor é observada a transição que deve estar relacionada à formação das micelas. A influência da presença de um agente hidrotrópico também foi avaliada em todas as soluções de copolímeros por meio do aumento no ponto de turvação com o aumento da concentração do agente hidrotrópico, visto que os picos endotérmicos foram deslocados para temperaturas mais altas.

The behavior of aqueous systems containing block copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), coupled to hydrocarbon groups, was evaluated by differential scanning calorimetry (DSC). Endothermic transitions in the copolymer solutions were observed under a linear heating rate and the initial temperatures of these transitions are in agreement with the cloud points of the copolymers studied. Two transitions were observed in the cooling curves; these transitions were better defined at faster cooling rates of the copolymer solutions which can be related to the micelles formation. The effect of the increasing concentration of the hydrotropic agent, sodium p-toluenesulfonate (NaPTS), in the copolymer solutions was observed by the increase in the cloud points given by the dislocation of the endothermic peaks to higher temperatures.

In the oil industry, the paraffination phenomenon is a major problem during oil production, displacement and treatment. Paraffin deposition in subsea flowlines, surface equipment, production string or even in the reservoir, can cause significant and increasing oil losses. To minimize paraffin precipitation, the application of magnetic field in the petroleum path has been suggested based on empiric studies. In this study, we assembled a labscale magnetic conditioner to determine the influence of magnetic field on the physical-chemical properties of two fluids : oil and a paraffin mixture. We observed that magnetic field reduce sample aparent viscosity due to crystal morphology alteration.

O asfalteno contido no petróleo pode se depositar gerando inúmeros problemas que podem afetar não só a produção, mas também todas as etapas que envolvem o transporte, armazenamento e processamento do óleo cru. Este trabalho apresenta uma adaptação matemática de modelos de interatividade para o sistema asfalteno/estabilizante capaz de prever o desempenho do estabilizante em evitar a precipitação de asfalteno. A capacidade do líquido da casca da castanha de caju (LCC) e de um dos seus derivados, o cardanol, foi estudada empregando-se o teste de peptização. Tanto o LCC quanto o cardanol apresentaram propriedades estabilizadoras de asfaltenos e exibiram interatividade positiva em ambos os casos.

Asphaltenes deposition may cause serious problems for crude oil production, treatment and refining. Additives that disperse or peptisize asphaltenes particles may prevent this deposition process, avoiding serious technological problems. The results presented in this paper show that the oil extracted from cashew nut shell and cardanol, one of its components, may be used as peptizing agent for asphaltenes. Furthermore, it is shown that dispersants display binding isotherms presenting typical co-operative association.