1,443 research outputs found

    Morphologic and Biochemical Changes in Dogs After Portacaval Shunt Plus Bile Fistula or Ileal Bypass: Failure of Bile Fistula or Ileal Bypass to Prevent Hepatocyte Atrophy

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    External biliary fistula (BF) or ileal bypass (IB) was performed in dogs at the time of or 2 weeks after portacaval shunt (PCS). The pathologic changes in the dog livers 2 to 4 weeks later were compared to those caused by PCS alone. Histopathologic differences between PCS alone vs. PCS plus BF or IB could not be found. Thus, the experiments did not confirm recent observations by others in rats that BF prevents or reverses the hepatic injury of PCS. As estimated by plasma mevalonic acid determinations, the increase in hepatic cholesterol synthesis that is characteristic after BF or IB was suppressed in animals with PCS. BF and IB reduced but did not eliminate the postprandial elevation in serum bile acid that occurs after PCS. The findings have possible relevance in planning the treatment of patients with familial hypercholesterolemia with the combined use of PCS and IB. Copyright © 1983 American Association for the Study of Liver Disease

    The Deep Poincare Map: A Novel Approach for Left Ventricle Segmentation

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    Precise segmentation of the left ventricle (LV) within cardiac MRI images is a prerequisite for the quantitative measurement of heart function. However, this task is challenging due to the limited availability of labeled data and motion artifacts from cardiac imaging. In this work, we present an iterative segmentation algorithm for LV delineation. By coupling deep learning with a novel dynamic-based labeling scheme, we present a new methodology where a policy model is learned to guide an agent to travel over the image, tracing out a boundary of the ROI – using the magnitude difference of the Poincaré map as a stopping criterion. Our method is evaluated on two datasets, namely the Sunnybrook Cardiac Dataset (SCD) and data from the STACOM 2011 LV segmentation challenge. Our method outperforms the previous research over many metrics. In order to demonstrate the transferability of our method we present encouraging results over the STACOM 2011 data, when using a model trained on the SCD dataset

    Performance optimization of a leagility inspired supply chain model: a CFGTSA algorithm based approach

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    Lean and agile principles have attracted considerable interest in the past few decades. Industrial sectors throughout the world are upgrading to these principles to enhance their performance, since they have been proven to be efficient in handling supply chains. However, the present market trend demands a more robust strategy incorporating the salient features of both lean and agile principles. Inspired by these, the leagility principle has emerged, encapsulating both lean and agile features. The present work proposes a leagile supply chain based model for manufacturing industries. The paper emphasizes the various aspects of leagile supply chain modeling and implementation and proposes a new Hybrid Chaos-based Fast Genetic Tabu Simulated Annealing (CFGTSA) algorithm to solve the complex scheduling problem prevailing in the leagile environment. The proposed CFGTSA algorithm is compared with the GA, SA, TS and Hybrid Tabu SA algorithms to demonstrate its efficacy in handling complex scheduling problems

    Superrevivals in the quantum dynamics of a particle confined in a finite square well potential

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    We examine the revival features in wave packet dynamics of a particle confined in a finite square well potential. The possibility of tunneling modifies the revival pattern as compared to an infinite square well potential. We study the dependence of the revival times on the depth of the square well and predict the existence of superrevivals. The nature of these superrevivals is compared with similar features seen in the dynamics of wavepackets in an anharmonic oscillator potential.Comment: 8 pages in Latex two-column format with 5 figures (eps). To appear in Physical Review

    Dementia as Zeitgeist: Social problem construction and the role of a contemporary distraction

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    The global impact of dementia on social, political, economic and health systems is of contemporary concern. As the world’s population ages, differentially, across countries in the Global North and Global South, dementia research and care has become embedded in primary mandates for action within the agendas of governments and health research and service organisations. Using notions of social problem construction and sociologies of legitimacy this paper seeks to explore dementia as Zeitgeist that has captured imaginations but as such is contingent and therefore precarious building an edifice that may be limited and may occlude dangers for people living with dementia. This paper argues for an applied sociological approach that recognises precarity and seeks to embed a sustainable praxis-focused axiology at macro, meso and micro levels in respect of approaches to dementia

    A review on BIPV-induced temperature effects on urban heat islands

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    Urban Heat Islands (UHI) occur in and around cities, leading to warmer temperatures than in surrounding rural areas. The UHI effect increases energy demand, air pollution levels, and heat-related illness and mortality. Solar energy is one of the most widely adopted renewable energy generation technologies in the built environment. Solar photovoltaic (PV) systems, integrated into building envelopes, can form a cohesive design, construction and energy solution for buildings, namely, building-integrated photovoltaic system (BIPV). However, the BIPV panels might potentially exacerbate the UHI intensity by trapping more heat in urban areas. This review paper uses a detailed literature survey of over 100 sources to evaluate whether the uptake of BIPV systems in urban areas contributes to an aggravation of the UHI effect. The survey found both direct and indirect impacts of BIPV systems on UHI, which also identified the fundamental causes of UHI such as the albedo effect and heat dispersion and how this would be embodied in the BIPV installations. Furthermore, this paper discusses how to mitigate the impact of BIPV systems on the UHI, as well as the future research directions around this concern in relation to the urban design

    Quantum gravitational contributions to quantum electrodynamics

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    Quantum electrodynamics describes the interactions of electrons and photons. Electric charge (the gauge coupling constant) is energy dependent, and there is a previous claim that charge is affected by gravity (described by general relativity) with the implication that the charge is reduced at high energies. But that claim has been very controversial with the situation inconclusive. Here I report an analysis (free from earlier controversies) demonstrating that that quantum gravity corrections to quantum electrodynamics have a quadratic energy dependence that result in the reduction of the electric charge at high energies, a result known as asymptotic freedom.Comment: To be published in Nature. 19 pages LaTeX, no figure

    Connectivity-based parcellation of the thalamus explains specific cognitive and behavioural symptoms in patients with bilateral thalamic infarct

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    A novel approach based on diffusion tractography was used here to characterise the cortico-thalamic connectivity in two patients, both presenting with an isolated bilateral infarct in the thalamus, but exhibiting partially different cognitive and behavioural profiles. Both patients (G.P. and R.F.) had a pervasive deficit in episodic memory, but only one of them (R.F.) suffered also from a dysexecutive syndrome. Both patients had an MRI scan at 3T, including a T1-weighted volume. Their lesions were manually segmented. T1-volumes were normalised to standard space, and the same transformations were applied to the lesion masks. Nineteen healthy controls underwent a diffusion-tensor imaging (DTI) scan. Their DTI data were normalised to standard space and averaged. An atlas of Brodmann areas was used to parcellate the prefrontal cortex. Probabilistic tractography was used to assess the probability of connection between each voxel of the thalamus and a set of prefrontal areas. The resulting map of corticothalamic connections was superimposed onto the patients' lesion masks, to assess whether the location of the thalamic lesions in R.F. (but not in G. P.) implied connections with prefrontal areas involved in dysexecutive syndromes. In G.P., the lesion fell within areas of the thalamus poorly connected with prefrontal areas, showing only a modest probability of connection with the anterior cingulate cortex (ACC). Conversely, R.F.'s lesion fell within thalamic areas extensively connected with the ACC bilaterally, with the right dorsolateral prefrontal cortex, and with the left supplementary motor area. Despite a similar, bilateral involvement of the thalamus, the use of connectivity-based segmentation clarified that R.F.'s lesions only were located within nuclei highly connected with the prefrontal cortical areas, thus explaining the patient's frontal syndrome. This study confirms that DTI tractography is a useful tool to examine in vivo the effect of focal lesions on interconnectivity brain patterns

    Impact of facial conformation on canine health: Brachycephalic Obstructive Airway Syndrome

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    The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring
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