1,639 research outputs found

    Dengue disease, basic reproduction number and control

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    Dengue is one of the major international public health concerns. Although progress is underway, developing a vaccine against the disease is challenging. Thus, the main approach to fight the disease is vector control. A model for the transmission of Dengue disease is presented. It consists of eight mutually exclusive compartments representing the human and vector dynamics. It also includes a control parameter (insecticide) in order to fight the mosquito. The model presents three possible equilibria: two disease-free equilibria (DFE) and another endemic equilibrium. It has been proved that a DFE is locally asymptotically stable, whenever a certain epidemiological threshold, known as the basic reproduction number, is less than one. We show that if we apply a minimum level of insecticide, it is possible to maintain the basic reproduction number below unity. A case study, using data of the outbreak that occurred in 2009 in Cape Verde, is presented.Comment: This is a preprint of a paper whose final and definitive form has appeared in International Journal of Computer Mathematics (2011), DOI: 10.1080/00207160.2011.55454

    Kidney segmentation in 3D CT images using B-Spline Explicit Active Surfaces

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    In this manuscript, we propose to adapt the B-Spline Explicit Active Surfaces (BEAS) framework for semi-automatic kidney segmentation in computed tomography (CT) images. To study the best energy functional for kidney CT extraction, three different localized region-based energies were implemented within the BEAS framework, namely localized Chan-Vese, localized Yezzi, and signed localized Yezzi energies. Moreover, a novel gradient-based regularization term is proposed. The method was applied on 18 kidneys from 9 CT datasets, with different image properties. Several energy combinations were contrasted using surface-based comparison against ground truth meshes, assessing their accuracy and robustness against surface initialization. Overall, the hybrid energy functional combining the localized signed Yezzi energy with gradient-based regularization simultaneously showed the highest accuracy and the lowest sensitivity to the initialization. Volumetric analysis demonstrated the feasibility of the method from a clinical point of view, with similar reproducibility to manual observers.The authors acknowledge FCT - Fundação para a Ciência e a Tecnologia, Portugal, and the European Social Found, European Union, for funding support through the Programa Operacional Capital Humano (POCH) in the scope of the PhD grants SFRH/BD/93443/2013 (S. Queirós) and SFRH/BD/95438/2013 (P. Morais).info:eu-repo/semantics/publishedVersio

    Augmented reality-assisted ultrasound breast biopsy

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    Breast cancer is the most prevalent cancer in the world and the fifth-leading cause of cancer-related death. Treatment is effective in the early stages. Thus, a need to screen considerable portions of the population is crucial. When the screening procedure uncovers a suspect lesion, a biopsy is performed to assess its potential for malignancy. This procedure is usually performed using real-time Ultrasound (US) imaging. This work proposes a visualization system for US breast biopsy. It consists of an application running on AR glasses that interact with a computer application. The AR glasses track the position of QR codes mounted on an US probe and a biopsy needle. US images are shown in the user’s field of view with enhanced lesion visualization and needle trajectory. To validate the system, latency of the transmission of US images was evaluated. Usability assessment compared our proposed prototype with a traditional approach with different users. It showed that needle alignment was more precise, with 92.67 ± 2.32° in our prototype versus 89.99 ± 37.49° in a traditional system. The users also reached the lesion more accurately. Overall, the proposed solution presents promising results, and the use of AR glasses as a tracking and visualization device exhibited good performance.This work was funded by the projects “NORTE-01-0145-FEDER-000045” and “NORTE-01- 0145-FEDER-000059", supported by Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). It was also funded by national funds, through the FCT (Fundação para a Ciência e a Tecnologia) and FCT/MCTES in the scope of the project UIDB/05549/2020, UIDP/05549/2020 and LASI-LA/P/0104/2020. The authors also acknowledge FCT, Portugal and the European Social Found, European Union, for funding support through the “Programa Operacional Capital Humano” (POCH) in the scope of the PhD grants SFRH/BD/136721/2018 (Oliveira B.) and SFRH/BD/136670 (Torres H. R.)

    Structural mechanical simulation to optimize the sensor arm geometry to be implemented on cranial remodeling orthosis

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    For the treatment of moderate and severe cases of deformational plagiocephaly, an asymmetrical deformation of the skull, a cranial remodeling orthosis (CRO) is used. For the development of a new CRO concept, a pressure sensor grid is placed inside the orthosis that will allow the monitoring of excessive pressures and incorrect CRO positioning throughout the treatment. To implement the sensor grid in the CRO, high mobility of the sensor arms structure that joins the several sensors of this grid is required, however, it is intended that this procedure does not damage the printed copper tracks on the sensor structure. In this study, computer simulations were performed to optimize the sensor arm structure geometry, minimizing undesirable mechanical behavior in the sensor structure when subjected to tensile forces and displacements applied during its placement in the CRO. It was observed that the different sensor arm structures geometries have different effects on the mechanical behavior of the sensor structure when subjected to tensile forces and tensile displacement. The zigzag curve geometry presents the best performance based on high mobility without intense strain on the structure that could damage the printed copper tracks.511F-603F-4B30 | Francisco MirandaN/

    No-match ORESTES explored as tumor markers

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    Sequencing technologies and new bioinformatics tools have led to the complete sequencing of various genomes. However, information regarding the human transcriptome and its annotation is yet to be completed. The Human Cancer Genome Project, using ORESTES (open reading frame EST sequences) methodology, contributed to this objective by generating data from about 1.2 million expressed sequence tags. Approximately 30% of these sequences did not align to ESTs in the public databases and were considered no-match ORESTES. On the basis that a set of these ESTs could represent new transcripts, we constructed a cDNA microarray. This platform was used to hybridize against 12 different normal or tumor tissues. We identified 3421 transcribed regions not associated with annotated transcripts, representing 83.3% of the platform. The total number of differentially expressed sequences was 1007. Also, 28% of analyzed sequences could represent noncoding RNAs. Our data reinforces the knowledge of the human genome being pervasively transcribed, and point out molecular marker candidates for different cancers. To reinforce our data, we confirmed, by real-time PCR, the differential expression of three out of eight potentially tumor markers in prostate tissues. Lists of 1007 differentially expressed sequences, and the 291 potentially noncoding tumor markers were provided

    No-match ORESTES explored as tumor markers

    Get PDF
    Sequencing technologies and new bioinformatics tools have led to the complete sequencing of various genomes. However, information regarding the human transcriptome and its annotation is yet to be completed. The Human Cancer Genome Project, using ORESTES (open reading frame EST sequences) methodology, contributed to this objective by generating data from about 1.2 million expressed sequence tags. Approximately 30% of these sequences did not align to ESTs in the public databases and were considered no-match ORESTES. On the basis that a set of these ESTs could represent new transcripts, we constructed a cDNA microarray. This platform was used to hybridize against 12 different normal or tumor tissues. We identified 3421 transcribed regions not associated with annotated transcripts, representing 83.3% of the platform. The total number of differentially expressed sequences was 1007. Also, 28% of analyzed sequences could represent noncoding RNAs. Our data reinforces the knowledge of the human genome being pervasively transcribed, and point out molecular marker candidates for different cancers. To reinforce our data, we confirmed, by real-time PCR, the differential expression of three out of eight potentially tumor markers in prostate tissues. Lists of 1007 differentially expressed sequences, and the 291 potentially noncoding tumor markers were provided

    Desigualdades sociais em saúde e o câncer de colo do útero no Brasil: uma análise da realidade brasileira

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    A detecção precoce do câncer de colo do útero, além de outros fatores, está intimamente relacionada com a prevenção e tratamento da infecção pelo papiloma vírus humano (HPV). Todavia, vários elementos contribuem para a detecção tardia e dificuldade de acesso aos tratamentos adequados. Por isso, objetivamos realizar um debate sobre os principais fatores condicionantes para a detecção tardia do câncer de colo do útero na Política Pública de Saúde do Brasil. Como método de construção deste trabalho realizamos uma abordagem qualitativa através de pesquisa de bibliografias relacionadas à temática. Percebemos com base nas bibliografias que, na população brasileira, os fatores de risco para o desenvolvimento de câncer de colo do útero estão intrinsecamente relacionados com o baixo nível socioeconômico e as grandes dificuldades de acesso à rede de atenção básica.Facultad de Trabajo Socia

    Desigualdades sociais em saúde e o câncer de colo do útero no Brasil: uma análise da realidade brasileira

    Get PDF
    A detecção precoce do câncer de colo do útero, além de outros fatores, está intimamente relacionada com a prevenção e tratamento da infecção pelo papiloma vírus humano (HPV). Todavia, vários elementos contribuem para a detecção tardia e dificuldade de acesso aos tratamentos adequados. Por isso, objetivamos realizar um debate sobre os principais fatores condicionantes para a detecção tardia do câncer de colo do útero na Política Pública de Saúde do Brasil. Como método de construção deste trabalho realizamos uma abordagem qualitativa através de pesquisa de bibliografias relacionadas à temática. Percebemos com base nas bibliografias que, na população brasileira, os fatores de risco para o desenvolvimento de câncer de colo do útero estão intrinsecamente relacionados com o baixo nível socioeconômico e as grandes dificuldades de acesso à rede de atenção básica.Facultad de Trabajo Socia

    Inhibiting Mycobacterium tuberculosis CoaBC by targeting an allosteric site.

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    Coenzyme A (CoA) is a fundamental co-factor for all life, involved in numerous metabolic pathways and cellular processes, and its biosynthetic pathway has raised substantial interest as a drug target against multiple pathogens including Mycobacterium tuberculosis. The biosynthesis of CoA is performed in five steps, with the second and third steps being catalysed in the vast majority of prokaryotes, including M. tuberculosis, by a single bifunctional protein, CoaBC. Depletion of CoaBC was found to be bactericidal in M. tuberculosis. Here we report the first structure of a full-length CoaBC, from the model organism Mycobacterium smegmatis, describe how it is organised as a dodecamer and regulated by CoA thioesters. A high-throughput biochemical screen focusing on CoaB identified two inhibitors with different chemical scaffolds. Hit expansion led to the discovery of potent and selective inhibitors of M. tuberculosis CoaB, which we show to bind to a cryptic allosteric site within CoaB
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