66 research outputs found

    Visual Odometer on Videos of Endoscopic Capsules (VOVEC)

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    Desde a sua introdução em 2001, as cápsulas endoscópicas tornaram-se o principal método para obter imagens do intestino - uma região de difícil acesso através de métodos de endoscopia tradicionais - revolucionando a maneira como os diagnósticos no campo das doenças do intestino delgado são feitos. Estas cápsulas com dimensões comparáveis a um comprimido vitamínico tiram partido de uma câmera wireless para criar vídeos de 8 a 10 horas do trato digestivo dos pacientes. Devido à longa duração dos vídeos produzidos, o diagnóstico humano é moroso, entediante e propício a erros. Para além disto, depois de encontrada uma lesão, a informação da sua localização é escassa e dependente de hardware externo, levando a que uma solução baseada apensa em software com precisão melhorada seja bastante desejada. Este trabalho advém desta necessidade e, tendo-a em mente, propomos a implementação de dois métodos baseados em deep-learning, visando melhorar em relação às limitações dos sistemas atuais de localização de cápsulas endoscópicas. Para treinar e testar as nossas redes neuronais, um dataset que contém 111 vídeos da cápsula PillCam SB3 e 338 da cápsula PillCam SB2 foi utilizado, cortesia do Centro Hospitalar do Porto (CHP).O primeiro método consiste numa simples estimação do deslocamento da cápsula ao longo do intestino delgado utilizando uma HomographyNet, uma abordagem de deep-learning supervisionado usada para o cálculo de homografias entre imagens.Já no segundo método uma posição relativa 3D da cápsula é fornecida ao longo do intestino delgado, recorrendo a um método não-supervisionado de deep-learning denominado SfMLearner. Este método combina uma DepthNet e uma PoseNet para aprender a profundidade da imagem e a posição da cápsula em simultâneo.Since its introduction in 2001, capsule endoscopy has become the leading screening method for the small bowel - a region not easily accessible with traditional endoscopy techniques - revolutionizing the way diagnostics work in the field of small bowel diseases. These capsules are vitamin-sized and leverage from a small wireless camera to create 8 to 10 hour videos of the patients digestive tract. Due to the long duration of the videos produced, the human-based diagnosis is elongated, tedious and error-prone. Moreover, once a lesion is found, the localization information is scarce and hardware dependent, entailing desirability for a software-only endoscopic capsule localization system with added precision. This work stems from this need and, bearing this in mind, we propose the implementation of two deep-learning based methods to improve upon the limitations of the techniques used so far for the capsule position estimation. To train and test our networks, a dataset of 111 PillCam SB3 and 338 PillCam SB2 videos were used, courtesy of Centro Hospitalar do Porto (CHP).The first method consists in a simple capsule displacement estimation throughout the small bowel utilizing HomographyNet, a deep learning supervised approach that is used for homography computation between images. (DeTone et al. (2016))Differently, the second proposed method is intended to provide a 3D position along the small intestine, utilizing a deep learning unsupervised approach labeled SfMLearner, which takes advantage of a combination between a DepthNet and a PoseNet to learn depth and ego-motion from video simultaneously. (Zhou et al. (2017)

    Prototype of an affordable pressure-controlled emergency mechanical ventilator for COVID-19

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    We present a viable prototype of a simple mechanical ventilator intended as a last resort to ventilate COVID-19 patients. The prototype implements the pressure-controlled continuous mandatory ventilation mode (PC-CMV) with settable breathing rates, inspiration/expiration time ratios and FiO2 modulation. Although safe, the design aims to minimize the use of technical components and those used are common in industry, so its construction may be possible in times of logistical shortage or disruption or in areas with reduced access to technical materials and at a moderate cost, affordable to lower income countries. Most of the device can be manufactured by modest technical means and construction plans are provided.Comment: This version differs from version 2 in that it includes toxicological and bio-safety tests and updated electronic

    Práticas artísticas no ensino básico e secundário

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    Sobre a Matéria-Prima, há novidades e perigos. O tempo vivido na Europa e no contexto global tem vindo a acentuar a urgência das prioridades quantificadas, com um discurso dominante onde há menos política (pessoas) e mais representação económica (coisas). O correlato entre pessoas e coisas é, como sabemos, o dinheiro, ou trabalho reificado. A crise europeia, em torno da dívida soberana e dos maiores orçamentos do mundo, da capacidade da sua gestão na linguagem dura dos mercados e das taxas de juro veio modificar os objetivos imediatos da Europa, que em 2000 eram ambiciosos — “a sociedade mais competitiva do mundo em 2010” — para uma estratégia de emergência, agora chamada horizonte 2020. Este é o panorama ideal para colocar o ensino artístico em risco. Os fóruns internacionais passaram a valorizar os resultados da educação em rankings e sondagens de aproveitamento, cuja principal estratégia e preocupação é a mensurabilidade e comparabilidade, como são exemplo os relatórios PISA: avaliam-se em todos os países, as competências em Ciências, Matemática e Língua Materna. A matéria-prima de amanhã corre riscos de desaparecer gradualmente, pelos cortes de carga horária, pela concepção extracurricular da educação artística, pela sua perceção menorizada em função das concepções competitivas da sociedade contemporânea globalizada.info:eu-repo/semantics/publishedVersio

    High frequency of WNT-activated medulloblastomas with CTNNB1 wild type suggests a higher proportion of hereditary cases in a Latin-Iberian population

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    PurposeMedulloblastomas are the most common primary malignant brain tumors in children. They are divided into molecular subgroups: WNT-activated, SHH-Activated, TP53 mutant or wild type, and non-WNT/non-SHH (Groups 3 and 4). WNT-activated medulloblastomas are usually caused by mutations in the CTNNB1 gene (85%–90%), and most remaining cases of CTNNB1 wild type are thought to be caused by germline mutations in APC. So far, the frequencies of CTNNB1 have been reported mainly in North American and European populations. The aim of this study was to report the frequency of CTNNB1 mutations in WNT-activated medulloblastomas in a Latin-Iberian population and correlate with their clinicopathological characteristics.MethodsA total of 266 medulloblastomas from seven different institutions from Brazil (n=211), Portugal (n=38), and Argentina (n=17) were evaluated. Following RNA and DNA isolation from formalin-fixed, paraffin-embedded (FFPE) tumor tissues, the molecular classification and CTNNB1 mutation analysis were performed by nCounter and Sanger sequencing, respectively.ResultsWNT-activated medulloblastomas accounted for 15% (40/266) of the series. We observed that 73% of WNT-activated medulloblastomas harbored CTNNB1 mutations. CTNNB1 wild-type cases (27%) were more prevalent in female individuals and suggested to be associated with a worse outcome. Among the CTNNB1 wild-type cases, the available analysis of family history revealed two cases with familiar adenomatous polyposis, harboring APC germline variants.ConclusionWe observed a lower incidence of CTNNB1 mutations in WNT-activated medulloblastomas in our Latin-Iberian cohort compared to frequencies previously described in other populations. Considering that CTNNB1 wild-type cases may exhibit APC germline mutations, our study suggests a higher incidence (~30%) of hereditary WNT-activated medulloblastomas in the Latin-Iberian population

    NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

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    Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

    Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

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    Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

    Prevalência e fatores de risco para leishmaniose e doença de Chagas na população canina da Estância Turística de Ibiúna, São Paulo, Brasil

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    The aims of the study were to determine the seroprevalence of leishmaniasis and Chagas disease, and to determine the risk factors associated with seropositivity in dogs in the tourist city of Ibiúna, São Paulo, Brazil. A total of 570 blood samples of dogs were collected from four regions in the 48 districts of the municipality, from September 2007 to March 2008, and submitted for serological examination. Laboratory diagnosis of leishmaniasis and Chagas disease was performed using indirect enzyme-linked immunosorbent assay and indirect immunofluorescence, respectively. Of the 570 animals examined, 13 (2.3%; 95% confidence interval [CI] = 1.2%-3.8%) were seropositive for leishmaniasis, and 35 (6.1%; 95% CI = 4.3%-8.3%) were seropositive for Chagas disease. A risk factor associated with seropositivity for Chagas disease in dogs was residence in a region with a predominance of small farms generally used for subsistence planting and leisure and surrounded by forest areas (odds ratio = 4.20). By contrast, there were no risk factors identified for leishmaniasis, leading us to conclude that leishmaniasis and Chagas disease are present in dogs in the tourist city of Ibiúna, São Paulo; however, additional studies are needed in order to fully define the risk factors associated with disease in this municipality.O objetivo do trabalho foi determinar a soroprevalência de leishmaniose e doença de Chagas, e determinar os fatores de risco associados com a soropositividade em cães da Estância Turística de Ibiúna, Estado de São Paulo, Brasil. Foram colhidas amostras de sangue de 570 cães distribuídos em quatro regiões nos 48 bairros do município, no período de setembro de 2007 a março de 2008 e submetidas a exame sorológico. O diagnóstico laboratorial da leishmaniose e da doença de Chagas foi efetuado com o teste de ELISA e com a reação de imunofluorescência indireta (RIFI), respectivamente. Dos 570 animais examinados, 13 (2,3%; IC 95% = 1,2% - 3,8%) foram soropositivos para leishmaniose, e 35 (6,1%; IC 95% = 4,3% - 8,3%) para doença de Chagas. As variáveis alimentação com comida caseira (OR = 5,28) e o animal ser procedente da região 4 (OR= 4,20) foram identificadas como fatores de risco associados à soropositividade para doença de Chagas, no entanto, não foram identificados fatores de risco para leishmaniose. Conclui-se que a leishmaniose e a doença de Chagas estão presentes em cães da Estância Turística de Ibiúna, São Paulo, e com base na análise de fatores de risco, recomenda-se evitar a administração de comida caseira aos cães
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