1,501 research outputs found

    Pulmonary ventilation/perfusion single photon emission tomography – Initial experience of a Nuclear Medicine Department

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    AbstractIntroductionLung ventilation/perfusion scintigraphy with planar images (V/QS-planar) is very useful for the diagnosis and follow-up of pulmonary thromboembolism (PTE). Acquiring tomographic images (V/QS-SPECT) is a recent development with potential to increase the technique's accuracy. The purpose of this work is to evaluate the added benefits of V/QS-SPECT studies as opposed to traditional planar imaging.Patients and methodsWe prospectively revised 53 V/QS-planar and V/QS-SPECT exams, performed according to the European Association of Nuclear Medicine guidelines. We evaluated the exams independently, by consensus of two Nuclear Medicine physicians. For both methods, we gave each lung a score expressing the dimension and extension of perfusion defects with normal ventilation. For each lung, we compared the scores with the paired Wilcoxon test, estimating the 95% confidence interval (95CI) for the respective difference.ResultsWe performed V/QS-SPECT exams without technical difficulties. The paired Wilcoxon test estimated the score difference to be −0.75 (95CI of −1.0 to −0.5; p-value=9.6×10−7), expressing a statistically significant difference of about 1 subsegmental defect between both methods, with V/QS-SPECT detecting more defects.DiscussionThe results demonstrate that V/QS-SPECT identifies a slightly larger number of perfusion defects than V/QS-planar, suggesting a higher sensitivity of this technique. However, more studies are necessary to evaluate the clinical meaning of this fact.ConclusionV/QS-SPECT demonstrates a higher capability to identify perfusion defects. This method looks promising, allowing for a greater role of this exam in pulmonary thromboembolism diagnosis and follow-up

    Challenges in control and autonomy of unmanned aerial-aquatic vehicles

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    Autonomous aquatic vehicles capable of flight can deploy more rapidly, access remote or constricted areas, overfly obstacles and transition easily between distinct bodies of water. This new class of vehicles can be referred as Unmanned Aerial-Aquatic Vehicles (UAAVs), and is capable of reaching distant locations rapidly, conducting measurements and returning to base. This greatly improves upon current solutions, which often involve integrating different types of vehicles (e.g. vessels releasing underwater vehicles), or rely on manpower (e.g. sensors dropped manually from ships). Thanks to recent research efforts, UAAVs are becoming more sophisticated and robust. Nonetheless numerous challenges remain to be addressed, and particularly dedicated control and sensing solutions are still scarce. This paper discusses challenges and opportunities in UAAV control, sensing and actuation. Following a brief overview of the state of the art, we elaborate on the requirements and challenges for the main types of robots and missions proposed in the literature to date, and highlight existing solutions where available. The concise but wide-ranging overview provided will constitute a useful starting point for researchers undertaking UAAV control work

    Cinesiterapia e Massoterapia

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    Fluorescence in nanostructured fulleride films

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    Applied Physics Letters, 89Nanostructuring of fullerene C60 beam deposited films is achieved by electrochemical reduction in a potassium hydroxide aqueous solution. Alkali fulleride clusters are formed at the electrode, as it is illustrated by cyclic voltammetry, x-ray diffraction, and scanning tunneling microscopy. Fluorescence emission from fluorophore doped fullerene reduced films was investigated by fluorescence spectroscopy and scanning near-field optical microscopy. These techniques lead to results which also fit such nanometer-sized fulleride cluster interpretation. In particular, the fluorophore fluorescence lifetime decreases as long as aggregation in the film is more effective,which occurs with the increase of film thickness

    Characterization of polymorphic microsatellite markers for the Neotropical leaf-frog Phyllomedusa burmeisteri and cross-species amplification

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    Twelve polymorphic tetranucleotide microsatellite loci were isolated and characterized for the leaf-frog Phyllomedusa burmeisteri, an endemic species of the Brazilian Atlantic forest. These loci were screened in 25 individuals from two populations of the Minas Gerais State (Carangola and Juiz de Fora). The number of alleles per locus ranged from 3 to 16 (mean = 8). Observed and expected heterozygosities ranged from 0.25 to 0.92 and 0.56 to 0.92, respectively. Evidence for both the presence of null alleles and Hardy-Weinberg equilibrium deviations were found in loci Phybu4, Phybu17, and Phybu21. Genotypic disequilibrium for each pair of loci across populations was not significant. Cross-species amplification was successful for 11 of the 12 developed loci for the sister-species, P. bahiana. These microsatellites will be important for future fine-scale population structure analyses
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