Mobile robot experimental modeling and control strategies using sensor fusion

This research work deals with the problem of modeling and design of low level speed controller for the mobile robot PRIM. The main objective is to develop an effective educational, and research tool. On one hand, the interests in using the open mobile platform PRIM consist in integrating several highly related subjects to the automatic control theory in an educational context, by embracing the subjects of communications, signal processing, sensor fusion and hardware design, amongst others. On the other hand, the idea is to implement useful navigation strategies such that the robot can be served as a mobile multimedia information point. It is in this context, when navigation strategies are oriented to goal achievement, that a local model predictive control is attained. Hence, such studies are presented as a very interesting control strategy in order to develop the future capabilities of the system. In this context the research developed includes the visual information as a meaningful source that allows detecting the obstacle position coordinates as well as planning the free obstacle trajectory that should be reached by the robot

Magnetism of isolated Mn12 single-molecule magnets detected by magnetic circular dichroism: Observation of spin tunneling with a magneto-optical technique

We report magnetic and magneto-optical measurements of two Mn12 single-molecule magnet derivatives isolated in organic glasses. Field-dependent magnetic circular dichroism (MCD) intensity curves (hysteresis cycles) are found to be essentially identical to superconducting quantum interference device magnetization results and provide experimental evidence for the potential of the optical technique for magnetic characterization. Optical observation of magnetic tunneling has been achieved by studying the decay of the MCD signal at weak applied magnetic field

15-OR: Multi-phase postmortem CT angiography of pulmonary embolism: technique-related artefacts or real findings?

Multi-phase postmortem CT angiography (MPMCTA) is recognized as a valuable tool to explore the vascular system, with higher sensitivity than conventional autopsy. However, a limitation is the impossibility to diagnose pulmonary embolism (PE) due to post-mortem blood clots situated in pulmonary arteries. The purpose of this study was to explore an eventual possibility to distinguish between real PE and artefacts mimicking PE. Our study included 416 medico-legal cases. All of them underwent MPMCTA, conventional autopsy and histological examination. We selected cases presenting arterial luminal filling defects in the pulmonary arteries. Their radiological interpretation was confronted to the one of autopsy and histological examination. We also investigated an eventual correlation between artefacts in pulmonary arteries and those in other parts of the vascular system. In 123 cases, filling defects of pulmonary arteries were described during MPMCTA. In 57 cases, this was interpreted as artefact and in 4 cases as suspected PE. In 62 cases only a differential diagnosis was made. Autopsy and histology could clearly identify the artefacts as such. Only one case of real PE was radiologically misinterpreted as artefact. In 6 of the 62 cases with no interpretation a PE was diagnosed. In 3 out of 4 suspected cases, PE was confirmed. We found out that filling defects in pulmonary arteries are nearly always associated to other vascular artefacts. Therefore, we suggest following some rules for radiological interpretation in order to allow a reliable diagnosis of pulmonary embolism after MPMCTA.

Laparoscopic Gastric Banding Outcomes Do Not Depend on Device or Technique. Long-Term Results of a Prospective Randomized Study Comparing the Lapband® and the SAGB®.

BACKGROUND: Gastric banding still represents one of the most widely used bariatric procedures. It provides acceptable weight loss in many patients, but has frequent long-term complications. Because different types of bands may lead to different results, we designed a randomized study to compare the Lapband® with the SAGB®. We hereby report on the long-term results. METHODS: Between December 1998 and June 2002, 180 morbidly obese patients were randomized between Lapband® or SAGB®. Weight loss, long-term morbidity, and need for reoperation were evaluated. RESULTS: Long-term weight loss did not differ between the two bands. Patients who maintained their band had an acceptable long-term weight loss of between 50 and 60 % EBMIL. In both groups, about half the patients developed long-term complications, with about 50 % requiring major redo surgery. There was no difference in the overall rates of long-term complications or failures between the two groups, but patients who had a Lapband® were significantly more prone to develop band slippage/pouch dilatation (13.3 versus 0 %, p < 0,001). CONCLUSIONS: Although in the absence of complication, gastric banding leads to acceptable weight loss; the long-term complication and major reoperation rates are very high independently from the type of band used or on the operative technique. Gastric banding leads to relatively poor overall long-term results and therefore should not be considered the procedure of choice for the treatment of morbid obesity. Patients should be informed of the limited overall weight loss and the very high complication rates.

A practical right-sided incisional gastropexy technique for treatment or prevention of gastric dilatation volvulus

Yhteenveto: Käytännöllinen oikeanpuoleinen viiltogastropeksia mahalaukun laajentumisen ja kiertymisen hoitona tai ennaltaehkäisynä

Evaluation of the inhalation technique in asthmatic children visiting a specialised outpatient clinic

Background and objective: Asthma is one of the most frequent chronic diseases affecting children and adolescents. Good compliance is indispensable for effective treatment since a suboptimal use of inhalation devices can result in decreased therapeutic efficacy and increased morbidity. The objective of this work was to evaluate the inhalation technique of paediatric patients visiting a specialized consultation clinic of a university hospital. Design: Observational prospective study during a 3-month period. Setting Specialized consultation clinic of a university hospital. Main outcome measures: This study involved 40 outpatient infants, children and adolescents visiting alone or with their parent(s). Patients' data (age, sex, weight, diagnostic, reason for consulting, previous consultations) and their medicines were compiled using an ad hoc form. Filmed sequences of the inhalation procedure used by each child were reviewed independently by members of an interdisciplinary team consisting in a physician, a pharmacist, a nurse and a physiotherapist. A score of 1 was assigned to each correct step in the procedure, and a score of 0 to an incorrect step. A perfect procedure implied 12 correct steps. Results: Thirty patients were treated with a metered-dose inhaler and an inhalation chamber (Babyhaler or AeroChamber Plus); ten other patients were treated with a dry powder inhaler (Diskus or Turbuhaler). The agreement between the members of the interdisciplinary team was considered satisfactory. Nine patients (22.5%) reached an average score lower than 7, 18 patients (45%) a score between 7 and 10 and 13 (32.5%) a score equal to or better than 10. No patient reached the maximum score of 12. Users of the metered-dose inhalers (average score = 9.2) showed a better technique than users of the dry powder inhalers (average score = 7.4). Disappointingly, the score was not improved during a second consultation or following regular consultations. Conclusions: Video recording is a simple method to evaluate the degree of mastery of an inhalation procedure in paediatric patients. The method allows a convenient and efficient identification of suboptimal procedure steps by the hospital staff, and opens the way to patient-specific teaching. In two-thirds of juvenile patients, their inhalation technique was suboptimal despite initial training. This study shows conclusively that the inhalation technique in paediatric patients must be monitored during each examination, and teaching measures taken to improve it when necessary.

Technique de reconstruction itérative VEO : évaluation en tomodensitométrie thoracique chez l'enfant.

Objectifs: Evaluer la technique de reconstruction itérative VEO en tomodensitométrie (TDM) du thorax chez l'enfant. Matériels et méthodes: Etude prospective, basée sur 20 patients (7-18 ans), suivis pour mucoviscidose et adressés pour TDM de suivi. Dix patients (groupe A) ont eu une acquisition basse-dose habituelle (BD). Dix patients (groupe B) ont eu une acquisition très-basse-dose (TBD) et ultra-basse-dose (UBD). Les acquisitions BD étaient reconstruites par rétroprojection filtrée (RPF), les acquisitions TBD et UBD étaient reconstruites par RPF et VEO. L'évaluation de VEO était basée sur la réduction de dose et la qualité des images (mesures de bruit et scores de visualisation des structures pulmonaires). Résultats: Une réduction de dose d'environ 50% était obtenue dans le groupe B. La réduction du bruit en VEO par rapport aux RPF était de 55% en TBD et de 75% en UBD. En VEO, une amélioration des scores de visualisation des structures pulmonaires était obtenue en TBD et UBD. Cependant, en VEO-UBD, la visualisation des structures distales demeuraient parfois insuffisante et celle des structures proximales était altérée par une modification de texture de l'image. Conclusion: Malgré une altération possible de la texture de l'image en UBD, la technique de reconstruction VEO est performante en réduction de dose et amélioration des images.

3D coronary vessel wall imaging utilizing a local inversion technique with spiral image acquisition.

Current 2D black blood coronary vessel wall imaging suffers from a relatively limited coverage of the coronary artery tree. Hence, a 3D approach facilitating more extensive coverage would be desirable. The straightforward combination of a 3D-acquisition technique together with a dual inversion prepulse can decrease the effectiveness of the black blood preparation. To minimize artifacts from insufficiently suppressed blood signal of the nearby blood pools, and to reduce residual respiratory motion artifacts from the chest wall, a novel local inversion technique was implemented. The combination of a nonselective inversion prepulse with a 2D selective local inversion prepulse allowed for suppression of unwanted signal outside a user-defined region of interest. Among 10 subjects evaluated using a 3D-spiral readout, the local inversion pulse effectively suppressed signal from ventricular blood, myocardium, and chest wall tissue in all cases. The coronary vessel wall could be visualized within the entire imaging volume.

FAM-MDR: a flexible family-based multifactor dimensionality reduction technique to detect epistasis using related individuals

We propose a novel multifactor dimensionality reduction method for epistasis detection in small or extended pedigrees, FAM-MDR. It combines features of the Genome-wide Rapid Association using Mixed Model And Regression approach (GRAMMAR) with Model-Based MDR (MB-MDR). We focus on continuous traits, although the method is general and can be used for outcomes of any type, including binary and censored traits. When comparing FAM-MDR with Pedigree-based Generalized MDR (PGMDR), which is a generalization of Multifactor Dimensionality Reduction (MDR) to continuous traits and related individuals, FAM-MDR was found to outperform PGMDR in terms of power, in most of the considered simulated scenarios. Additional simulations revealed that PGMDR does not appropriately deal with multiple testing and consequently gives rise to overly optimistic results. FAM-MDR adequately deals with multiple testing in epistasis screens and is in contrast rather conservative, by construction. Furthermore, simulations show that correcting for lower order (main) effects is of utmost importance when claiming epistasis. As Type 2 Diabetes Mellitus (T2DM) is a complex phenotype likely influenced by gene-gene interactions, we applied FAM-MDR to examine data on glucose area-under-the-curve (GAUC), an endophenotype of T2DM for which multiple independent genetic associations have been observed, in the Amish Family Diabetes Study (AFDS). This application reveals that FAM-MDR makes more efficient use of the available data than PGMDR and can deal with multi-generational pedigrees more easily. In conclusion, we have validated FAM-MDR and compared it to PGMDR, the current state-of-the-art MDR method for family data, using both simulations and a practical dataset. FAM-MDR is found to outperform PGMDR in that it handles the multiple testing issue more correctly, has increased power, and efficiently uses all available information.

The International Universities Walking Project: Development of a Framework for Workplace Intervention Using the Delphi Technique

Background: This paper aimed to use the Delphi technique to develop a consensus framework for a multinational, workplace walking intervention. Methods: Ideas were gathered and ranked from eight recognized and emerging experts in the fields of physical activity and health, from universities in Australia, Canada, England, the Netherlands, Northern Ireland, and Spain. Members of the panel were asked to consider the key characteristics of a successful campus walking intervention. Consensus was reached by an inductive, content analytic approach, conducted through an anonymous, three-round, e-mail process. Results: The resulting framework consisted of three interlinking themes defined as “design, implementation, and evaluation.” Top-ranked subitems in these themes included the need to generate research capacity (design), to respond to group needs through different walking approaches (implementation), and to undertake physical activity assessment (evaluation). Themes were set within an underpinning domain, referred to as the “institution” and sites are currently engaging with subitems in this domain, to provide sustainable interventions that reflect the practicalities of local contexts and needs. Conclusions: Findings provide a unique framework for designing, implementing, and evaluating walking projects in universities and highlight the value of adopting the Delphi technique for planning international, multisite health initiatives.

Improved Surgical Technique Reduces Complications at the Gastro-jejunostomy After Laparoscopic Roux-en-Y Gastric Bypass

Introduction: Roux-en-Y gastric bypass (RYGBP) is one of the commonest procedure for morbid obesity. It is associated with effective long-term weight loss, but can lead to significant complications, especially at the gastrojejunostomy (GJS) Patients and Methods: All the patients undergoing laparoscopic RYGBP at one of our two institutions were included in this study, in which we compared two different techniques for the construction of the GJS and their effects on the incidence of complications. In group A, anatomosis was performed on the posterior aspect of the gastric pouch. In group B it was performed across the staple line used to form the gastric pouch. A 21-mm circular stapler was used in all patients. Results: A total of 1128 patients were included between June 1999 and September 2009, 639 in group A and 488 in group B. Sixty patients developed a total of 65 complications at the GJS, with 14 (1,2 %) leaks, 42 (3,7 %) stricture, and 9 (0,8 %) marginal ulcers. Leaks (0,2 versus 2 %, p=0,005) and strictures (0,8 versus 5,9%, p<0,0001) were significantly fewer in group B than in group A. Conclusions: Improved surgical technique, with the GJS across the staple line used to form the gastric pouch, significantly reduces the rate of anastomotic complications at the GJS. A circular 21-mm stapler can be used with a low complication rate, and especially a low stricture rate. Additional methods to limit complications at the GJS are probably not routinely warranted.

Imagens do sensor MODIS associadas a um modelo agronômico para estimar a produtividade de soja

O objetivo deste trabalho foi estimar a produtividade de soja no Rio Grande do Sul, nas safras de 2000/2001 a 2002/2003, por meio de um modelo agronômico implementado em um Sistema de Informação Geográfica (SIG). Duas abordagens foram utilizadas: o modelo agronômico (AGRO), com valores de índice de área foliar (IAF) obtidos da literatura; e o modelo agronômico-espectral (AGROESPEC), com valores de IAF estimados a partir das imagens MODIS (moderate resolution imaging spectroradiometer). As estimativas de produtividade obtidas pelo modelo foram comparadas àquelas fornecidas pelo Instituto Brasileiro de Geografia e Estatística (IBGE), com o uso do teste t para pares de observação. Nas safras 2000/2001 e 2001/2002, não foram observadas diferenças significativas. Para 2002/2003, o modelo subestimou o valor de produtividade em 7,87 e 7,04%, nas abordagens AGRO e AGROESPEC, respectivamente, em comparação à produtividade fornecida pelo IBGE. Ambas as abordagens do modelo permitiram avaliação objetiva e quantitativa do efeito das condições meteorológicas sobre a produtividade de soja. Entretanto, o AGROESPEC forneceu estimativas mais detalhadas, no que se refere à variação espacial da produtividade, em razão do emprego dos valores de IAF estimados a partir das imagens MODIS.

Mapeamento da temperatura da superfície terrestre com uso do sensor AVHRR/NOAA

O objetivo deste trabalho foi avaliar a adequação do uso do sensor AVHRR/NOAA (Advanced Very High Resolution Radiometer/National Oceanic and Atmospheric Administration) para mapeamento da temperatura da superfície terrestre (TST) no Estado do Rio Grande do Sul, por meio da comparação entre três algoritmos clássicos. Foram comparados os métodos de Becker & Li, Sobrino et al. e Kerr et al. para estimativa das TST mínimas, utilizando imagens noturnas e logo após o amanhecer. Os dados de emissividade e TST foram obtidos por meio de combinações matemáticas da radiação detectada nas faixas do visível, infravermelho próximo e termal do sensor AVHRR/NOAA. O sensor AVHRR é adequado para o mapeamento de TST para as condições do tipo de cobertura do solo que predominam no Rio Grande do Sul, visto que a TST estimada pelos três métodos testados foi próxima à temperatura do ar medida nos locais selecionados. O método de Sobrino et al. foi o mais adequado.

A new technique with high reproducibility to estimate renal oxygenation using BOLD-MRI in chronic kidney disease.

OBJECTIVES: To assess inter-observer variability of renal blood oxygenation level-dependent MRI (BOLD-MRI) using a new method of analysis, called the concentric objects (CO) technique, in comparison with the classical ROI (region of interest)-based technique. METHODS: MR imaging (3T) was performed before and after furosemide in 10 chronic kidney disease (CKD) patients (mean eGFR 43±24ml/min/1.73m(2)) and 10 healthy volunteers (eGFR 101±28ml/min1.73m(2)), and R2* maps were determined on four coronal slices. In the CO-technique, R2* values were based on a semi-automatic procedure that divided each kidney in six equal layers, whereas in the ROI-technique, all circles (ROIs) were placed manually in the cortex and medulla. The mean R2*values as assessed by two independent investigators were compared. RESULTS: With the CO-technique, inter-observer variability was 0.7%-1.9% across all layers in non-CKD, versus 1.6%-3.8% in CKD. With the ROI-technique, median variability for cortical and medullary R2* values was 3.6 and 6.8% in non-CKD, versus 4.7 and 12.5% in CKD; similar results were observed after furosemide. CONCLUSION: The CO-technique offers a new, investigator-independent, highly reproducible alternative to the ROI-based technique to estimate renal tissue oxygenation in CKD.