60 research outputs found

    Near-wall hemodynamic parameters quantification in in vitro intracranial aneurysms with 7 T PC-MRI.

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    OBJECTIVE Wall shear stress (WSS) and its derived spatiotemporal parameters have proven to play a major role on intracranial aneurysms (IAs) growth and rupture. This study aims to demonstrate how ultra-high field (UHF) 7 T phase contrast magnetic resonance imaging (PC-MRI) coupled with advanced image acceleration techniques allows a highly resolved visualization of near-wall hemodynamic parameters patterns in in vitro IAs, paving the way for more robust risk assessment of their growth and rupture. MATERIALS AND METHODS We performed pulsatile flow measurements inside three in vitro models of patient-specific IAs using 7 T PC-MRI. To this end, we built an MRI-compatible test bench, which faithfully reproduced a typical physiological intracranial flow rate in the models. RESULTS The ultra-high field 7 T images revealed WSS patterns with high spatiotemporal resolution. Interestingly, the high oscillatory shear index values were found in the core of low WSS vortical structures and in flow stream intersecting regions. In contrast, maxima of WSS occurred around the impinging jet sites. CONCLUSIONS We showed that the elevated signal-to-noise ratio arising from 7 T PC-MRI enabled to resolve high and low WSS patterns with a high degree of detail

    Improved convergence of scattering calculations in the oscillator representation

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    The Schr\"odinger equation for two and tree-body problems is solved for scattering states in a hybrid representation where solutions are expanded in the eigenstates of the harmonic oscillator in the interaction region and on a finite difference grid in the near-- and far--field. The two representations are coupled through a high--order asymptotic formula that takes into account the function values and the third derivative in the classical turning points. For various examples the convergence is analyzed for various physics problems that use an expansion in a large number of oscillator states. The results show significant improvement over the JM-ECS method [Bidasyuk et al, Phys. Rev. C 82, 064603 (2010)]

    Severe Cholestasis and Bile Cast Nephropathy Induced by Anabolic Steroids Successfully Treated with Plasma Exchange

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    We report a case of a bodybuilder who took a regimen of anabolic steroids containing stanozolol and testosterone propionate for 8 weeks which led to the development of jaundice and severe pruritus with serum total bilirubin reaching 41.22 mg/dL. Despite supportive care with fluid and albumin therapy, serum creatinine was progressively increasing. He underwent 6 successful sessions of plasma exchange (PE) with marked improvement at the end of the sessions. Three months after discharge, the patient’s creatinine and total bilirubin levels were 1.08 mg/dL and 1.2 mg/dL, respectively

    Solutions to Combat Anthropogenic Climate Change Impacts: A Review of “Drawdown”

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    The Drawdown book surfs through 100 possible solutions and technologies. Those solutions could help mitigate GHG emissions in order to constrain climate change. In this book review, we examine the estimated CO2 reduction levels as well as the costs of each solution. Alternative cement, smart thermostats, and geothermal energy are the top cost-effective solutions. We, however, discuss our top five solutions, according to the combination of their potential drawdown, cost effectiveness, and future development. Those solutions target refrigerants, wind energy, food, cement, and female education. Overall, the book could inform people with little or no knowledge about well-known solutions to mitigating climate change footprints. Nevertheless, the numbers and costs are too speculative to ponder for policy making

    Cavitation Erosion Prediction on Francis Turbines Part 2 : Model Tests and Flow Analysis

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    Different measurement techniques have been used to detect cavitation on a Francis turbine model. The results are compared to those obtained on the prototype and presented in the first of this series of articles. The runner mode! used for that study is built on the basis of a geometrical recovery of one of most eroded blade of the prototype. The results of the different measurements are presented and commented by comparison with prototype measurements. This comparison leads to a proposal of the physics which should be involved in transposition laws for the prediction of prototype erosion from cavitation mode! tests. The consequences of such scaling laws, as well as their application to the prototype and mode! results, are part of the third facet of this work

    L'HydroptĂšre: A story of a dream

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    In 2009, l’Hydroptùre broke the symbolic barrier of 50 knots and became the world fastest sailing boat over both 500 meters and 1 nautical mile. This major achievement relied on the high skills of the sailing team but also on technical advances of the boat, resulting from long years of studies and development. This achievement is also an open window to a new goal: flying around the world. In the present article, we present this long and incredible story, highlighting the different steps, the technology involved, and the background of that project.

    Induction of protein citrullination and auto-antibodies production in murine exposed to nickel

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    Abstract Citrullination, or the post-translational deimination of polypeptide-bound arginine, is involved in several pathological processes in the body, including autoimmunity and tumorigenesis. Recent studies have shown that nanomaterials can trigger protein citrullination, which might constitute a common pathogenic link to disease development. Here we demonstrated auto-antibody production in serum of nanomaterials-treated mice. Citrullination-associated phenomena and PAD levels were found to be elevated in nanomaterials -treated cell lines as well as in the spleen, kidneys and lymph nodes of mice, suggesting a systemic response to nanomaterials injection, and validated in human pleural and pericardial malignant mesothelioma (MM) samples. The observed systemic responses in mice exposed to nanomaterials support the evidence linking exposure to environmental factors with the development of autoimmunity responses and reinforces the need for comprehensive safety screening of nanomaterials. Furthermore, these nanomaterials induce pathological processes that mimic those observed in Pleural MM, and therefore require further investigations into their carcinogenicity
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