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    Stellar occultations enable milliarcsecond astrometry for Trans-Neptunian objects and Centaurs

    , Article Astronomy and Astrophysics ; Volume 644 , 2020 Rommel, F. L ; Braga Ribas, F ; Desmars, J ; Camargo, J. I. B ; Ortiz, J. L ; Sicardy, B ; Vieira-Martins, R ; Assafin, M ; Santos-Sanz, P ; Duffard, R ; Fernández Valenzuela, E ; Lecacheux, J ; Morgado, B. E ; Benedetti Rossi, G ; Gomes-Júnior, A. R ; Pereira, C. L ; Herald, D ; Hanna, W ; Bradshaw, J ; Morales, N ; Brimacombe, J ; Burtovoi, A ; Carruthers, T ; De Barros, J. R ; Fiori, M ; Gilmore, A ; Hooper, D ; Hornoch, K ; Jacques, C ; Janik, T ; Kerr, S ; Kilmartin, P ; Winkel, J.M ; Naletto, G ; Nardiello, D ; Nascimbeni, V ; Newman, J ; Ossola, A ; Pál, A ; Pimentel, E ; Pravec, P ; Sposetti, S ; Stechina, A ; Szakáts, R ; Ueno, Y ; Zampieri, L ; Broughton, J ; Dunham, J. B ; Dunham, D.W ; Gault, D ; Hayamizu, T ; Hosoi, K ; Jehin, E ; Jones, R ; Kitazaki, K ; Komž Ík, R ; Marciniak, A ; Maury, A ; Mikuž, H ; Nosworthy, P ; Fábrega Polleri, J ; Rahvar, S ; Sfair, R ; Siqueira, P. B ; Snodgrass, C ; Sogorb, P ; Tomioka, H ; Tregloan Reed, J ; Winter, O. C ; Sharif University of Technology
    EDP Sciences  2020
    Abstract
    Context. Trans-Neptunian objects (TNOs) and Centaurs are remnants of our planetary system formation, and their physical properties have invaluable information for evolutionary theories. Stellar occultation is a ground-based method for studying these distant small bodies and has presented exciting results. These observations can provide precise profiles of the involved body, allowing an accurate determination of its size and shape. Aims. The goal is to show that even single-chord detections of TNOs allow us to measure their milliarcsecond astrometric positions in the reference frame of the Gaia second data release (DR2). Accurate ephemerides can then be generated, allowing predictions of... 

    Preparation of PVA nanocomposites using salep-reduced graphene oxide with enhanced mechanical and biological properties

    , Article RSC Advances ; Volume 5, Issue 112 , 2015 , Pages 92428-92437 ; 20462069 (ISSN) Pourjavadi, A ; Pourbadiei, B ; Doroudian, M ; Azari, S ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    Salep, known as a biodegradable polysaccharide, is hydrolyzed and used as both a reducing agent and stabilizer for graphene oxide (GO). The functionalized reduced graphene oxide (f-rGO) is homogenously dispersed in an aqueous solution of poly(vinyl alcohol) (PVA). PVA based hydrogel and film nanocomposites are prepared and proposed as new biomaterials for tissue engineering applications. The mechanical properties of the film nanocomposites are investigated with varying content of f-rGO, glycerol and citric acid as a reinforcing agent, a plasticizer agent and a cross linking agent respectively. For the first time, chemically cross linked PVA hydrogels are synthesized using... 

    Comparison between electrochemical and photoelectrochemical detection of dopamine based on titania-ceria-graphene quantum dots nanocomposite

    , Article Biosensors and Bioelectronics ; Volume 151 , 2020 Ahmadi, N ; Bagherzadeh, M ; Nemati, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this study, titania-ceria-graphene quantum dot (TC-GQD) nanocomposite was synthesized by hydrothermal method for the first time. The prepared nanomaterials were characterized by XRD, FTIR dynamic light scattering (DLS), FESEM, HRTEM, and EDX spectroscopy along with elemental mapping. The synergistic effect of the nanocomposite components was studied by diffuse reflectance spectroscopy (DRS) and electrical conductivity meter. The results showed that band gap of TC-GQD nanocomposite was shifted to visible lights relative to its components (1.3 eV), and electrical conductivity of the sample was significant increased to 89.5 μS cm−1. After chemical and physical characterization, prepared new...