3,874 research outputs found

    Correlação entre a avaliação clínico-fonoaudiológica e a eletromiográfica do músculo masseter

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    OBJECTIVE: The objective of this paper was to evaluate the specificity of masseter muscle palpation when compared to its electromyographic activity. MATERIALS AND METHODS: Twenty-one young female adults, aged between 17 and 25, participated in this research. The speech therapy evaluation data were obtained by two speech therapists through masseter muscle palpation during isometric contraction, and the electromyographic exam was achieved by using bipolar superficial electrodes, positioned on the masseter muscle. The volunteers were instructed to chew the Parafilm M® material bilaterally and simultaneously. The capture of the electromiographic signals occurred during masseter muscle isometric contractions. The electrical activity study of the masticatory muscle was analyzed through the Root Mean Square value during its isotonic contraction. STATISTICAL ANALYSIS: All data were then submitted to Kappa statistical analysis. RESULTS: The results of this study have shown a low correlation between palpation and electromyography (25%), as well as between evaluators (40%). CONCLUSION: According to the findings of the present study, it could be observed that the correlation between masseter muscle palpation and its electromyographic activity was very low, which allows to conclude that muscular palpation cannot effectively replace the eletromyographical exam, but complement it instead.OBJETIVO: Este trabalho teve como objetivo avaliar a correlação entre os resultados obtidos na palpação e os dados obtidos no exame eletromiográfico do músculo masseter. MATERIAL E MÉTODO: Participaram deste estudo 21 adultos jovens do sexo feminino, idades entre 17-25 anos. Os dados da avaliação fonoaudiológica foram obtidos por meio da palpação do músculo masseter durante a contração isométrica por dois fonoaudiólogos e os dados eletromiográficos foram captados com a utilização de eletrodos de superfície bipolares posicionados no músculo masseter durante a contração isotônica, sendo os voluntários orientados a mastigar bilateral e simultaneamente o material Parafilme®.O estudo da atividade elétrica do músculo mastigatório foi analisado pelo valor de RMS (Root Mean Square) na contração isotônica do músculo. ANÁLISE ESTATÍSTICA: Todos os dados foram submetidos à análise estatística Kappa. RESULTADOS: Os resultados deste estudo indicaram baixa correlação entre a palpação e a eletromiografia (25%) e entre avaliadores (40%). CONCLUSÃO: a partir dos achados do presente estudo, que a correlação entre os dados obtidos na palpação do músculo masseter em relação aos dados obtidos no exame eletromiográfico foi muito baixa. Os resultados indicam que a palpação muscular não substitui o exame eletromiográfico, devendo complementá-lo

    Adaptive Seeding for Gaussian Mixture Models

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    We present new initialization methods for the expectation-maximization algorithm for multivariate Gaussian mixture models. Our methods are adaptions of the well-known KK-means++ initialization and the Gonzalez algorithm. Thereby we aim to close the gap between simple random, e.g. uniform, and complex methods, that crucially depend on the right choice of hyperparameters. Our extensive experiments indicate the usefulness of our methods compared to common techniques and methods, which e.g. apply the original KK-means++ and Gonzalez directly, with respect to artificial as well as real-world data sets.Comment: This is a preprint of a paper that has been accepted for publication in the Proceedings of the 20th Pacific Asia Conference on Knowledge Discovery and Data Mining (PAKDD) 2016. The final publication is available at link.springer.com (http://link.springer.com/chapter/10.1007/978-3-319-31750-2 24

    Machine-learning of atomic-scale properties based on physical principles

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    We briefly summarize the kernel regression approach, as used recently in materials modelling, to fitting functions, particularly potential energy surfaces, and highlight how the linear algebra framework can be used to both predict and train from linear functionals of the potential energy, such as the total energy and atomic forces. We then give a detailed account of the Smooth Overlap of Atomic Positions (SOAP) representation and kernel, showing how it arises from an abstract representation of smooth atomic densities, and how it is related to several popular density-based representations of atomic structure. We also discuss recent generalisations that allow fine control of correlations between different atomic species, prediction and fitting of tensorial properties, and also how to construct structural kernels---applicable to comparing entire molecules or periodic systems---that go beyond an additive combination of local environments

    Retinal blood vessels extraction using probabilistic modelling

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    © 2014 Kaba et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.The analysis of retinal blood vessels plays an important role in detecting and treating retinal diseases. In this review, we present an automated method to segment blood vessels of fundus retinal image. The proposed method could be used to support a non-intrusive diagnosis in modern ophthalmology for early detection of retinal diseases, treatment evaluation or clinical study. This study combines the bias correction and an adaptive histogram equalisation to enhance the appearance of the blood vessels. Then the blood vessels are extracted using probabilistic modelling that is optimised by the expectation maximisation algorithm. The method is evaluated on fundus retinal images of STARE and DRIVE datasets. The experimental results are compared with some recently published methods of retinal blood vessels segmentation. The experimental results show that our method achieved the best overall performance and it is comparable to the performance of human experts.The Department of Information Systems, Computing and Mathematics, Brunel University

    ReadClear: An Assistive Reading Tool for People Living with Posterior Cortical Atrophy

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    BACKGROUND: Progressive reading impairment is an early and debilitating symptom of posterior cortical atrophy (PCA) arising from the progressive deterioration of visual processing skills. OBJECTIVE: The goal of this study was to test the effectiveness of a purpose-built reading app (ReadClear) co-produced with people living with PCA and designed to reduce the reading difficulties experienced by this population (e.g., getting lost in the page and missing words when reading). METHODS: Twenty subjects with PCA were included in a cross-over design home-based study aimed at determining whether ReadClear could 1) enhance the subjective reading experience (reading pleasantness) and 2) improve reading accuracy (reducing the number of reading errors) compared with a sham condition (a standard e-reader). RESULTS: Reading using ReadClear provided a better subjective reading experience than sham (p = 0.018, d = 0.5) and significantly reduced the percentage of reading errors (p <  0.0001, r = 0.82), particularly errors due to omissions (p = 0.01, r = 0.50), repeated words (p = 0.002, r = 0.69), and regressions in the text (p = 0.003, r = 0.69). We found that different kinds of reading errors were related to specific neuropsychological profiles. CONCLUSION: ReadClear can assist reading in people living with PCA by reducing the number of reading errors and improving the subjective reading experience of users

    Mechanical Systems with Symmetry, Variational Principles, and Integration Algorithms

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    This paper studies variational principles for mechanical systems with symmetry and their applications to integration algorithms. We recall some general features of how to reduce variational principles in the presence of a symmetry group along with general features of integration algorithms for mechanical systems. Then we describe some integration algorithms based directly on variational principles using a discretization technique of Veselov. The general idea for these variational integrators is to directly discretize Hamilton’s principle rather than the equations of motion in a way that preserves the original systems invariants, notably the symplectic form and, via a discrete version of Noether’s theorem, the momentum map. The resulting mechanical integrators are second-order accurate, implicit, symplectic-momentum algorithms. We apply these integrators to the rigid body and the double spherical pendulum to show that the techniques are competitive with existing integrators

    Microalgae production in fresh market wastewater and its utilization as a protein substitute in formulated fish feed for oreochromis spp.

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    Rapid growing of human population has led to increasing demand of aquaculture production. Oreochromis niloticus or known as tilapia is one of the most globally cultured freshwater fish due to its great adaptation towards extreme environment. Besides, farming of tilapia not only involves small scales farming for local consumption but also larger scales for international market which contributes to a foreign currency earning. Extensive use of fishmeal as feed for fish and for other animals indirectly caused an increasing depletion of the natural resource and may consequently cause economic and environmental unstable. Microalgae biomass seems to be a promising feedstock in aquaculture industry. It can be used for many purposes such as live food for fish larvae and dried microalgae to substitute protein material in fish feed. The microalgae replacement in fish feed formulation as protein alternative seem potentially beneficial for long term aqua-business sustainability. The present chapter discussed the potential of microalgae as an alternative nutrition in fish feed formulations, specifically Tilapia

    Abnormal skeletal muscle blood flow, contractile mechanics and fibre morphology in a rat model of obese‐HFpEF

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    Peripheral skeletal muscle and vascular alterations induced by heart failure with preserved ejection fraction (HFpEF) remain poorly identified, with limited therapeutic targets. This study used a cardiometabolic obese‐HFpEF rat model to comprehensively phenotype skeletal muscle mechanics, blood flow, microvasculature and fibre atrophy. Lean (n = 8) and obese‐HFpEF (n = 8) ZSF1 rats were compared. Skeletal muscles (soleus and diaphragm) were assessed for in vitro contractility (isometric and isotonic properties) alongside indices of fibre‐type cross‐sectional area, myosin isoform, and capillarity, and estimated muscle PO2. In situ extensor digitorum longus (EDL) contractility and femoral blood flow were assessed. HFpEF soleus demonstrated lower absolute maximal force by 22%, fibre atrophy by 24%, a fibre‐type shift from I to IIa, and a 17% lower capillary‐to‐fibre ratio despite increased capillary density (all P 0.05). Soleus isotonic properties (shortening velocity and power) were impaired by up to 17 and 22%, respectively (P < 0.05), while the magnitude of the exercise hyperaemia was attenuated by 73% (P = 0.012) in line with higher muscle fatigue by 26% (P = 0.079). Diaphragm alterations (P < 0.05) included Type IIx fibre atrophy despite Type I/IIa fibre hypertrophy, with increased indices of capillarity alongside preserved contractile properties during isometric, isotonic, and cyclical contractions. In conclusion, obese‐HFpEF rats demonstrated blunted skeletal muscle blood flow during contractions in parallel to microvascular structural remodelling, fibre atrophy, and isotonic contractile dysfunction in the locomotor muscles. In contrast, diaphragm phenotype remained well preserved. This study identifies numerous muscle‐specific impairments that could exacerbate exercise intolerance in obese‐HFpEF

    Retargeted adenoviruses for radiation-guided gene delivery

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    The combination of radiation with radiosensitizing gene delivery or oncolytic viruses promises to provide an advantage that could improve the therapeutic results for glioblastoma. X-rays can induce significant molecular changes in cancer cells. We isolated the GIRLRG peptide that binds to radiation-inducible 78 kDa glucose-regulated protein (GRP78), which is overexpressed on the plasma membranes of irradiated cancer cells and tumor-associated microvascular endothelial cells. The goal of our study was to improve tumor-specific adenovirus-mediated gene delivery by selectively targeting the adenovirus binding to this radiation-inducible protein. We employed an adenoviral fiber replacement approach to conduct a study of the targeting utility of GRP78-binding peptide. We have developed fiber-modified adenoviruses encoding the GRP78-binding peptide inserted into the fiber-fibritin. We have evaluated the reporter gene expression of fiber-modified adenoviruses in vitro using a panel of glioma cells and a human D54MG tumor xenograft model. The obtained results demonstrated that employment of the GRP78-binding peptide resulted in increased gene expression in irradiated tumors following infection with fiber-modified adenoviruses, compared with untreated tumor cells. These studies demonstrate the feasibility of adenoviral retargeting using the GRP78-binding peptide that selectively recognizes tumor cells responding to radiation treatment

    Planet Populations as a Function of Stellar Properties

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    Exoplanets around different types of stars provide a window into the diverse environments in which planets form. This chapter describes the observed relations between exoplanet populations and stellar properties and how they connect to planet formation in protoplanetary disks. Giant planets occur more frequently around more metal-rich and more massive stars. These findings support the core accretion theory of planet formation, in which the cores of giant planets form more rapidly in more metal-rich and more massive protoplanetary disks. Smaller planets, those with sizes roughly between Earth and Neptune, exhibit different scaling relations with stellar properties. These planets are found around stars with a wide range of metallicities and occur more frequently around lower mass stars. This indicates that planet formation takes place in a wide range of environments, yet it is not clear why planets form more efficiently around low mass stars. Going forward, exoplanet surveys targeting M dwarfs will characterize the exoplanet population around the lowest mass stars. In combination with ongoing stellar characterization, this will help us understand the formation of planets in a large range of environments.Comment: Accepted for Publication in the Handbook of Exoplanet
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