83 research outputs found

    Study of the charge profile of thermally poled electrets

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    The charge profile of thermally poled electrets has been studied using two different methods, laser induced pressure pulse (LIPP) and pulsed electroacoustic (PEA), to gain insight into the mechanisms that are activated and assess which is the most appropriate method to study the charge profile. Disc--shaped PET samples have been conventionally poled to activate both the alpha and the rho relaxation and, right after, partially discharged up to a temperature Tpd. In this way, samples with a different combination of dipolar and space charge polarization have been obtained. Both LIPP and PEA reveal asymmetric profiles for Tpd below the glass transition temperature, that progressively become antisymmetric for higher temperatures. The shape and evolution of the charge profiles can be explained assuming injection of negative carriers from the anode that enhances the trapping of positive carriers near this electrode. It can be observed that PEA is able to detect a wider variety of polarization mechanisms in the system while LIPP gives a simpler picture of the charge profile.Comment: 19 pages, 11 figure

    Towards a global initiative for fibrosis treatment (GIFT).

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    Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterised by increased scarring of lung tissue. Despite the recent introduction of novel drugs that slow disease progression, IPF remains a deadly disease, and the benefits of these new drugs differ markedly between patients. Human diseases arise due to alterations in an almost limitless network of interconnected genes, proteins, metabolites, cells and tissues, in direct relationship with a continuously changing macro- or microenvironment. Systems biology is a novel research strategy that seeks to understand the structure and behaviour of the so-called "emergent properties" of complex systems, such as those involved in disease pathogenesis, which are most often overlooked when just one element of disease pathogenesis is observed in isolation. This article summarises the debate that took place during a European Respiratory Society research seminar in Barcelona, Spain on December 15-16, 2016, which focused on how systems biology could generate new data by integrating the different IPF pathogenic levels of complexity. The main conclusion of the seminar was to create a global initiative to improve IPF outcomes by integrating cutting-edge international research that leverages systems biology to develop a precision medicine approach to tackle this devastating disease

    Symbolic Dynamic Analysis of Relations Between Cardiac and Breathing Cycles in Patients on Weaning Trials

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    Traditional time-domain techniques of data analysis are often not sufficient to characterize the complex dynamics of the cardiorespiratory interdependencies during the weaning trials. In this paper, the interactions between the heart rate (HR) and the breathing rate (BR) were studied using joint symbolic dynamic analysis. A total of 133 patients on weaning trials from mechanical ventilation were analyzed: 94 patients with successful weaning (group S) and 39 patients that failed to maintain spontaneous breathing (group F). The word distribution matrix enabled a coarse-grained quantitative assessment of short-term nonlinear analysis of the cardiorespiratory interactions. The histogram of the occurrence probability of the cardiorespiratory words presented a higher homogeneity in group F than in group S, measured with a higher number of forbidden words in group S as well as a higher number of words whose probability of occurrence is higher than a probability threshold in group S. The discriminant analysis revealed the best results when applying symbolic dynamic variables. Therefore, we hypothesize that joint symbolic dynamic analysis provides enhanced information about different interactions between HR and BR, when comparing patients with successful weaning and patients that failed to maintain spontaneous breathing in the weaning procedure

    On the Role of Kinesthetic Thinking in Computational Geometry

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    Computational geometry is a new (about 30 years) and rapidly growing branch of knowledge in computer science that deals with the analysis and design of algorithms for solving geometric problems. These problems typically arise in computer graphics, image processing, computer vision, robotics, manufacturing, knot theory, polymer physics and molecular biology. Since its inception many of the algorithms proposed for solving geometric problems, published in the literature, have been found to be incorrect. These incorrect algorithms rather than being \purely mathematical" often contain a strong kinesthetic component. This paper explores the relationship between computational geometric thinking and kinesthetic thinking, the eect of the latter on the correctness and eciency of the resulting algorithms, and their implications for education
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