14 research outputs found

    The Image of Rapid Change

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    An overview of neuro-oncology research and practice in Iran, three years with the NOSC initiative

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    Research and practice of neuro-oncology compiles clinical neuroscience expertise from neurosurgery, radiation oncology, neuroradiology, medical oncology, neuropathology and related disciplines to optimize planning and therapy in central nervous system malignancies. Such an interdisciplinary context prompted health-care providers from all related disciplines to establish the Neuro-Oncology Scientific Club (NOSC) in Iran and let it flourish since 3 years ago. With the advent of advanced technologies and through continued share of experience, NOSC members have tried to provide more integrated diagnoses and therapeutic care to brain tumor patients across the country. NOSC activities revolve around some key tenets including dissemination of education and updates, facilitation of institutional collaborations; data registry and patients� awareness. By virtue of recent insights on molecular characterization of brain tumors such as codeletion of chromosomes 1p and 19q in anaplastic gliomas and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation in glioblastoma, a range of translational research is being followed within NOSC. The most recent NOSC meeting which was held in Tehran, recapitulated main advances and dealt with the current debates on functional neurosurgery, biological markers and neuroimaging, risk prediction models in high grade gliomas and clinical issues in pediatric neuro-oncology. This article gives an overview of current hotspots in neuro-oncology research and practice which are pursued within NOSC. © 2015, Int J Clin Exp Med. All rights reserved

    Impact of palladium/palladium hydride conversion on electrochemical CO2 reduction via in-situ transmission electron microscopy and diffraction

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    Abstract Electrochemical conversion of CO2 offers a sustainable route for producing fuels and chemicals. Pd-based catalysts are effective for converting CO2 into formate at low overpotentials and CO/H2 at high overpotentials, while undergoing poorly understood morphology and phase structure transformations under reaction conditions that impact performance. Herein, in-situ liquid-phase transmission electron microscopy and select area diffraction measurements are applied to track the morphology and Pd/PdHx phase interconversion under reaction conditions as a function of electrode potential. These studies identify the degradation mechanisms, including poisoning and physical structure changes, occurring in PdHx/Pd electrodes. Constant potential density functional theory calculations are used to probe the reaction mechanisms occurring on the PdHx structures observed under reaction conditions. Microkinetic modeling reveals that the intercalation of *H into Pd is essential for formate production. However, the change in electrochemical CO2 conversion selectivity away from formate and towards CO/H2 at increasing overpotentials is due to electrode potential dependent changes in the reaction energetics and not a consequence of morphology or phase structure changes

    Impact of palladium/palladium hydride conversion on electrochemical CO<sub>2</sub> reduction via in-situ transmission electron microscopy and diffraction

    No full text
    Electrochemical conversion of CO2 offers a sustainable route for producing fuels and chemicals. Pd-based catalysts are effective for converting CO2 into formate at low overpotentials and CO/H2 at high overpotentials, while undergoing poorly understood morphology and phase structure transformations under reaction conditions that impact performance. Herein, in-situ liquid-phase transmission electron microscopy and select area diffraction measurements are applied to track the morphology and Pd/PdHx phase interconversion under reaction conditions as a function of electrode potential. These studies identify the degradation mechanisms, including poisoning and physical structure changes, occurring in PdHx/Pd electrodes. Constant potential density functional theory calculations are used to probe the reaction mechanisms occurring on the PdHx structures observed under reaction conditions. Microkinetic modeling reveals that the intercalation of *H into Pd is essential for formate production. However, the change in electrochemical CO2 conversion selectivity away from formate and towards CO/H2 at increasing overpotentials is due to electrode potential dependent changes in the reaction energetics and not a consequence of morphology or phase structure changes.</p

    Simulation of surface strain in tibiofemoral cartilage during walking for the prediction of collagen fibre orientation

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    <p>The collagen fibres in the superficial layer of tibiofemoral articular cartilage exhibit distinct patterns in orientation revealed by split lines. In this study, we introduce a simulation framework to predict cartilage surface loading during walking to investigate if split line orientations correspond with principal strain directions in the cartilage surface. The two-step framework uses a multibody musculoskeletal model to predict tibiofemoral kinematics which are then imposed on a deformable model to predict surface strains. The deformable model uses absolute nodal coordinate formulation (ANCF) shell elements to represent the articular surface and a system of spring-dampers and internal pressure to represent the underlying cartilage. Simulations were performed to predict surface strains due to internal pressure, loading induced by walking, and the combination of both loading due to pressure and walking. Peak femoral and tibial cartilage deflections were slightly greater than 1 mm during simulated walking. First principal strain magnitudes within the cartilage surface ranged up to 3%. Time-averaged first principal strains agreed best with split line maps from the literature when surface loading due to internal cartilage pressure was included. This result suggests there may be a connection between pressure-induced surface strain patterns and the collagen fibre orientation patterns that emerge.</p
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