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    CsPbBr3 single-crystal growth by temperature-lowering method as a case study for EGS4 benchmarking against commercial radiation detectors
    (Pergamon-Elsevier Science Ltd, 2026) Ozen, Songul Akbulut; Ozen, Murat; Celik, Necati
    CsPbBr3 single-crystals were synthesized using a hydrobromic acid-based temperature-lowering method, and their structural and optical properties were confirmed by XRD, DSC, and UV-Vis analyses. A solubility curve was established to optimize growth conditions, enabling enlargement of the seeded crystals. The radiation detection potential of CsPbBr3 was evaluated using EGS4 Monte Carlo simulations across photon energies ranging from 10 keV to 1 MeV. Simulated full-energy peak efficiencies and resolution values were compared with conventional detectors (Si(Li), NaI, and HPGe) and with alternative perovskite derivatives (CH3NH3PbBr3, Cs4PbBr6, CsPb2Br5). CsPbBr3 exhibited efficiency scaling with detector volume and resolution behavior consistent with the statistical 1/root E dependence typical of direct-gap semiconductors. While HPGe maintained superior intrinsic resolution, CsPbBr3 offered promising room-temperature performance without cryogenic requirements. These results demonstrate that the temperature-lowering method provides a viable route to scalable CsPbBr3 single-crystals and confirm their potential as cost-effective, high-Z semiconductor detectors for X- and gamma-ray applications. The findings establish a foundation for the further optimization of perovskite-based radiation detection technologies.
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    Evaluating the Anticancer Potential of Green-Synthesized Silver/Silver Oxide and Copper/Copper Oxide Nanoparticles From Walnut Leaf Extract on Prostate Cancer Cells
    (Wiley-V C H Verlag Gmbh, 2025) Aksel, Mehran; Ozen, Murat; Karaagac, Dursun
    Green synthesis is a method used to obtain metal/metal oxide nanoparticles from plant roots, stems, and leaves. In this study, Ag/Ag2O and Cu/CuO nanoparticles (NPs) were synthesized by utilizing the reducing, stabilizing and capping properties of the extract obtained from walnut (Juglans regia) leaves. The characteristic properties of the synthesized NPs were determined using UV-visible spectrophotometry (UV-vis), fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray diffraction (EDX), and powder X-ray diffraction (XRD). SEM images showed that Ag/Ag2O and Cu/CuO NPs were spherical in shape, with particle diameters ranging from 15 to 85 nm. EDX analysis confirmed the presence of silver, copper, and oxygen elements. The cytotoxic activity of the green-synthesized NPs was evaluated in vitro against PC3 prostate cancer cells and L929 fibroblast cells. Ag/Ag2O and Cu/CuO NPs exhibited significant cytotoxic activity against PC3 cells but showed comparatively lower cytotoxicity toward L929 cells. In contrast, the walnut leaf extract alone did not exhibit cytotoxic activity. According to the results, the synthesized nanoparticles demonstrated a cytotoxic effect on PC3 prostate cancer cells, and this effect was mediated through apoptosis.
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    Exploring barium-titanium-peroxo-hydroxide as an excellent single-source precursor for crystallographically diverse barium titanate ceramics - parametric study
    (Elsevier Sci Ltd, 2024) Ozen, Murat; Mertens, Myrjam; Cool, Pegie
    Barium-titanium-peroxo type amorphous materials gained importance with the advent of wet-chemical methods for the production of crystalline perovskite barium titanate (BaTiO3) electroceramics. In this paper, the chemical nature of the barium-titanium-peroxo precursor was determined by means of elemental (EPMA), spectroscopic (FT-IR and FT-Raman), XRD and thermal (DSC and TGA/DTA) analyses. Several synthesis parameters such as the barium source, the peroxide treatment time, the reaction temperature and the reaction time were investigated. The precursor was also thermally treated at varying temperatures between 30 degrees C and 1000 degrees C. Relatively high reaction temperatures are detrimental to the Ba center dot O center dot Ti structure, resulting in plain TiO2 formation. Though relatively low temperatures (ice bath) are needed to suppress unwanted TiOCl2, ambient synthesis conditions and short reaction time (2 h) resulted in the desired single-source properties, i.e. amorphous Ba center dot O center dot Ti-peroxo structure with Ba/Ti ratio of unity (1.04 +/- 0.04). The addition of an extra stirring step during H2O2 addition lowered the chance of carbonate incorporation in the precursor. Thermal analysis under air and nitrogen atmosphere was performed and a stoichiometric formula of Ba2,08Ti2O(O2)1,9(OH)5,3 center dot 3,1H2O was calculated, which was in very good agreement with literature data. The barium-titanium-peroxo-hydroxide material proved to be an excellent single-source precursor. Phase-pure, highly crystalline and facetted, stoichiometric BaTiO3 particles with differently crystallographically oriented facets were obtained via the molten-salt solid-state method ({100} or {111} oriented facets) as well as the hydrothermal route ({100} oriented facets).
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    Health risk assessment of soil trace elements using the Sequential Gaussian Simulation approach
    (Springer Heidelberg, 2022) Akbulut Ozen, Songul; Yesilkanat, Cafer Mert; Ozen, Murat; Bassari, Asiye; Taskin, Halim
    In this study, the performance of the Sequential Gaussian Simulation (SGS) approach was studied with the aim of accurately determining local health risk distributions associated with trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, As, and Pb). This study plays a crucial role in determining the distribution of health risk levels, especially from heavy metals. In the SGS approach, health risk levels (non-carcinogenic and carcinogenic) were calculated for pixel sizes of 250 x 250 m(2). Results were compared to the conventional Ordinary Kriging (OK) method. The cross-validation performances of both methods were compared. Non-carcinogenic health risks calculated according to SGS and OK for children were, respectively, rho(c): 0.57 and 0.23, RMSE: 0.45 and 0.57, and MAE: 0.33 and 0.43. In the case of adults, non-carcinogenic SGS and OK results were, respectively, rho(c): 0.53 and 0.24, RMSE: 0.06 and 0.07, and MAE: 0.04 and 0.05 for adults. Carcinogenic health risk estimates obtained by SGS and OK were, respectively, rho(c): 0.72 and 0.31, RMSE: 4.1 x 10(-5) and 5.8 x 10(-5), and MAE: 3.2 x 10(-5) and 4.3 x 10(-5) in the case of children, and in the case of adults the results were, respectively, rho(c): 0.71 and 0.30, RMSE: 5 x 10(-6) and 4.3 x 10(-6), and MAE: 4 x 10(-6) and 5 x 10(-6). These results indicated that SGS offered a more accurate approach in determining health risk distributions.
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    Study of the hydrothermal crystallization process of barium titanate by means of X-ray mass attenuation coefficient measurements at an energy of 59.54 keV
    (Elsevier Science Inc, 2017) Akbulut Özen, Songül; Ozen, Murat; Sahin, Mehmet; Mertens, Myrjam
    In this work, the X-ray mass attenuation coefficients of hydrothermally synthesized barium titanate (BaTiO3) samples were calculated with the purpose of determining the crystallization sequence of BaTiO3. Hydrothermally synthesized samples prepared at 100 degrees C and 200 degrees C, and reacted for varying reaction times between 15 min up to 120 h were studied. Attenuation coefficient measurements were done with a coaxial HPGe gamma detector (Ortec, GEM55P4-95) with a working range in the X-ray energy region. The samples were made into pellets and were exposed to Am-241 radioisotopes at an energy of 59.54 keV for 300 s. Additionally, FT-Raman and XRD measurements were done to support the X-ray mass attenuation measurements. It was found that secondary barium titanate (BT) phases (BaTi2O5 and Ba2TiO4) were formed from the precursor material at the early stages of the hydrothermal reaction and that phase pure BaTiO3 was formed at longer reaction times. The sequence of barium titanate crystallization was determined as follows: BaTi2O5; BaTi2O5 and BaTiO3; BaTi2O5, Ba2TiO4 and BaTiO3: and phase pure BaTiO3.