Browsing by Author "Deliormanll A.M."

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    Electrically conductive borate-based bioactive glass scaffolds for bone tissue engineering applications
    (SAGE Publications Ltd, 2017) Turk M.; Deliormanll A.M.
    In this study, electrically conductive, borate-based, porous 13-93B3 bioactive glass composite scaffolds were prepared using a polymer foam replication technique. For this purpose, a slurry containing 40 vol% glass particles and 0-10 wt% graphene nanoplatelets was prepared by dispersing the particles in ethanol in the presence of ethyl cellulose. Composite scaffolds were subjected to a controlled heat treatment, in air atmosphere, to decompose the foam and sinter the glass particles into a dense network. It was found that the applied heat treatment did not influence the structure of graphene in the glass network. Graphene additions did not negatively affect the mechanical properties and enhanced the electrical conductivity of the glass scaffolds. In X-ray diffraction analysis, the crystalline peak corresponding to hydroxyapatite was observed in all the samples suggesting that all of the samples were bioactive after 30 days of immersion in simulated body fluid. However, Fourier transform infrared spectroscopy analysis and scanning electron microscope observations revealed that hydroxyapatite formation rate decreased with increasing graphene concentration especially for samples treated in simulated body fluid for shorter times. Based on the cytotoxicity assay findings, the MC3T3-E1 cell growth was significantly inhibited by the scaffolds containing higher amount of graphene compared to bare glass scaffolds. Best performance was obtained for 5 wt% graphene which yielded an enhancement of electrical conductivity with moderate cellular response and in vitro hydroxyapatite forming ability. The study revealed that the electrically conductive 13-93B3 graphene scaffolds are promising candidates for bone tissue engineering applications. © The Author(s) 2017.
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    Finite element method simulation for the prediction of mechanical properties of three-dimensional periodic bioactive glass scaffolds
    (Springer International Publishing, 2017) Deliormanll A.M.; Deliormanll A.H.
    The desired mechanical properties of porous tissue engineering scaffolds may differ depending on the clinical applications. Therefore, it is crucial to be able to control these properties for specific cases. In the current study, cube shape, porous, silicate-based (13-93) bioactive glass scaffolds were fabricated by robotic deposition method. Scaffolds were prepared layer by layer to form constructs with a grid-like microstructure. After binder burnout, the constructs were sintered for 1 h at 700 °C to produce scaffolds consisting of dense bioactive glass struts (∼280 ± 20 μm in diameter) at different pore widths (300 ± 50, 600 ± 25, and 900 ± 50 μm). The mechanical response of the scaffolds in compression was measured experimentally. The stress analysis of the complete scaffolds with varying pore width and layer spacing parameters has been performed by finite element method (FEM) under compression to investigate the state of stress fields created within the scaffolds. Such an analysis can be used to vary several geometrical parameters and to choose the most suitable ones for the replacement of natural tissues. The compressive strengths predicted by the FEM simulations were successfully validated by comparison with experimental uniaxial compression test data, justifying the suitability of the present approach for the optimization purposes. © 2017 Australian Ceramic Society.
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    Towards better understanding of structural, physical and radiation attenuation properties of the granites in Aegean region of Turkey: İzmir and Kütahya Provinces
    (Institute of Physics, 2022) Deliormanll A.M.; Deliormanll A.H.; Turan F.; Issa S.A.M.; Almisned G.; Tekin H.O.
    In this study, physical, chemical, structural and radiation attenuation properties of some granite samples collected from Kütahya-Simav and İzmir (Bergama and Karaburun) were investigated. The true particle density of the studied granite samples was in the range of 2.65 g cm-3 to 2.72 g cm-3 and the median particle diameter was between ∼12 μm and 41 μm. According to the structural examination results obtained from the study, the chemical compositions of the extracted granite samples varied by area. While SiO2 was the dominating component in certain locations, it was replaced by Fe2O3 in another. This condition also had a direct effect on the densities of the granite samples extracted. At the conclusion of the study, it was found that the predominant factor affecting the radiation shielding characteristics of granites was the quantity of Fe2O3 in the composition, with the greatest gamma-ray shielding qualities supplied by samples 4 and 5, which had the highest Fe2O3 ratio. Our results indicate that sample 5 and the previously studied Capao Bonita sample had comparable half value layer values at low, medium, and high gamma ray levels. It may be concluded that Izmir granites are a more attractive option to granite for usage as radiation shielding building materials, owing to their high Fe2O3 concentration, and may be a feasible alternative to less desirable concrete materials for shielding applications. © 2022 IOP Publishing Ltd.