565 research outputs found

    HCV Infection in Patients with Hereditary Bleeding Disorders

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    Introduction: Hepatitis C virus (HCV) infection in patients with hereditary bleeding disorders (HBDs), as a consequence of treatment with transfusion of human bloodderived components between the late 1970s and 1980s, represents a major health concern. Objectives: Assessment and evaluation of the burden of HCV infection, its complications, and treatment in a population of patients with HBDs. Methods: Analysis of a series of 161 patients with HBDs treated in the Immunohemotherapy Service of the Centro Hospitalar de Lisboa Central (Lisboa, Portugal), consultation and systematic review of the patients clinical processes, elaboration of a database comprising the information gathered; and statistical study of its variables: age, gender, degree of severity of the bleeding disorder, treatment modality, and major and minor complications of HCV infection. Results: Sixty-five (40%) of the 161 patients have HCV infection. Among the patients with hemophilia A, 36% are severe and 62% of those have HCV infection; 9% moderate with 57%; 25% mild with 20%. In the hemophilia B group, 8% are severe with 23% infected and 6% moderate or mild with 10%. Concerning the patients with von Willebrand disease, 12% have type 2 with 16% infected and 4% have type 3 with 86%. Conclusions: HCV infection represents a very significant complication of the treatment employed in the past in the studied population. Considering that most of these patients were infected in the late 1970s and early 1980s, and the natural evolution of HCV infection in patients without bleeding disorders, it is expected that the prevalence of major complications will rise significantly in the coming years. Prophylactic measures should be implemented to enhance the follow-up protocols and prevent further development of liver damage in these patients

    Relevância da Infecção VHC em Coagulopatias Congénitas

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    Introdução: A infecção pelo vírus da hepatite C (VHC) em doentes com coagulopatias congénitas (CC), como consequência da terapêutica empregue entre os anos 70 e 80 com transfusão de derivados de plasma humano, constitui um problema de saúde substancial e relevante. Objectivos: Análise e avaliação da relevância representada pela infecção VHC e suas complicações no tratamento duma população de doentes com CC. Métodos: Análise retrospectiva duma série de 161 doentes com CC tratados no Serviço de Imunohemoterapia do Centro Hospitalar de Lisboa Central (Lisboa, Portugal). Revisão sistemática de processos clínicos. Elaboração duma base de dados compreendendo a informação reunida e estudo estatístico das suas variáveis: idade, género, tipo e gravidade da coagulopatia e modalidade de tratamento. Relativamente à infecção por VHC: genotipo, tipo e duração do tratamento, frequência de resposta mantida ao tratamento e recidiva, co-infecções e complicações major e minor. Resultados: Dos 161 doentes 65 (40%) estão infectados pelo VHC. Dos doentes com hemofilia A: 36% são grave e 62% dos quais estão infectados pelo VHC; 9% moderada com 57%; 25% ligeira com 20%. No grupo da hemofilia B: 8% são grave com 23% infectados e 6% moderada ou ligeira com 10%. Relativamente ao grupo com doença de von Willebrand: 12% são tipo 2 com 16% infectados e 4% tipo 3 com 86%. Uma coorte de 26 doentes foi submetida a terapêutica para a infecção pelo VHC, com o primeiro doente a receber tratamento em 1993. Destes, 5 eram seropositivos para o VIH. O tratamento variou de monoterapia com interferão a terapêutica combinada de interferão ou interferão-peguilado com ribavirina. Conclusões: A infecção pelo VHC representa uma complicação significativa do tratamento empregue no passado na população em estudo. Considerando que a maioria destes doentes foi infectada nos finais dos anos 70 e início dos anos 80 assim como a evolução natural da infecção pelo VHC em doentes sem CC, prevê-se que a prevalência de complicações major deverá aumentar significativamente nos próximos anos. É de suma importância a implementação de medidas profilácticas na revisão e adaptação dos protocolos de seguimento de forma a prevenir a progressão da patologia hepática nestes doentes

    The effect of minimum quantity lubrication in the intermittent turning of magnesium based on vibration signals

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    The present work shows an experimental investigation on intermittent turning based on vibration signals. The dependence of vibrations on the feed rate, minimum quantity lubrication (MQL) flow rate and the type of the interruption of the workpiece is evaluated. The results indicate that a part of the vibrations depends on the flow rate of the MQL system and its interaction with the feed rate, finding no dependency on the type of interruption. The influence of the MQL system is greater when machining at the lower feed rate. In addition, a strong relation between surface roughness and vibrations is identified. However, this relation is quite different depending on the environment used. In general, under dry conditions, the higher the vibrations the higher the surface roughness, while the opposite occurs when the MQL system is used.publishe

    Updating known distribution models for forecasting climate change impact on endangered species

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    To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species’ distribution, instead of building new models that are based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS

    Automatic Detection of Malignant Masses in Digital Mammograms Based on a MCET-HHO Approach

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    Digital image processing techniques have become an important process within medical images. These techniques allow the improvement of the images in order to facilitate their interpretation for specialists. Within these are the segmentation methods, which help to divide the images by regions based on different approaches, in order to identify details that may be complex to distinguish initially. In this work, it is proposed the implementation of a multilevel threshold segmentation technique applied to mammography images, based on the Harris Hawks Optimization (HHO) algorithm, in order to identify regions of interest (ROIs) that contain malignant masses. The method of minimum cross entropy thresholding (MCET) is used to select the optimal threshold values for the segmentation. For the development of this work, four mammography images were used (all with presence of a malignant tumor), in their two views, craniocaudal (CC) and mediolateral oblique (MLO), obtained from the Digital Database for Screening Mammography (DDSM). Finally, the ROIs calculated were compared with the original ROIs of the database through a series of metrics, to evaluate the behavior of the algorithm. According to the results obtained, where it is shown that the agreement between the original ROIs and the calculated ROIs is significantly high, it is possible to conclude that the proposal of the MCET-HHO algorithm allows the automatic identification of ROIs containing malignant tumors in mammography images with significant accuracy.Digital image processing techniques have become an important process within medical images. These techniques allow the improvement of the images in order to facilitate their interpretation for specialists. Within these are the segmentation methods, which help to divide the images by regions based on different approaches, in order to identify details that may be complex to distinguish initially. In this work, it is proposed the implementation of a multilevel threshold segmentation technique applied to mammography images, based on the Harris Hawks Optimization (HHO) algorithm, in order to identify regions of interest (ROIs) that contain malignant masses. The method of minimum cross entropy thresholding (MCET) is used to select the optimal threshold values for the segmentation. For the development of this work, four mammography images were used (all with presence of a malignant tumor), in their two views, craniocaudal (CC) and mediolateral oblique (MLO), obtained from the Digital Database for Screening Mammography (DDSM). Finally, the ROIs calculated were compared with the original ROIs of the database through a series of metrics, to evaluate the behavior of the algorithm. According to the results obtained, where it is shown that the agreement between the original ROIs and the calculated ROIs is significantly high, it is possible to conclude that the proposal of the MCET-HHO algorithm allows the automatic identification of ROIs containing malignant tumors in mammography images with significant accuracy

    Power Law versus Exponential State Transition Dynamics: Application to Sleep-Wake Architecture

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    BACKGROUND: Despite the common experience that interrupted sleep has a negative impact on waking function, the features of human sleep-wake architecture that best distinguish sleep continuity versus fragmentation remain elusive. In this regard, there is growing interest in characterizing sleep architecture using models of the temporal dynamics of sleep-wake stage transitions. In humans and other mammals, the state transitions defining sleep and wake bout durations have been described with exponential and power law models, respectively. However, sleep-wake stage distributions are often complex, and distinguishing between exponential and power law processes is not always straightforward. Although mono-exponential distributions are distinct from power law distributions, multi-exponential distributions may in fact resemble power laws by appearing linear on a log-log plot. METHODOLOGY/PRINCIPAL FINDINGS: To characterize the parameters that may allow these distributions to mimic one another, we systematically fitted multi-exponential-generated distributions with a power law model, and power law-generated distributions with multi-exponential models. We used the Kolmogorov-Smirnov method to investigate goodness of fit for the "incorrect" model over a range of parameters. The "zone of mimicry" of parameters that increased the risk of mistakenly accepting power law fitting resembled empiric time constants obtained in human sleep and wake bout distributions. CONCLUSIONS/SIGNIFICANCE: Recognizing this uncertainty in model distinction impacts interpretation of transition dynamics (self-organizing versus probabilistic), and the generation of predictive models for clinical classification of normal and pathological sleep architecture
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