Yazar "Temuz, Mehmet Mursit" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Investigation of the effects of quercetin on the structure and properties of zinc-modified hydroxyapatites
    (Univ Novi Sad, Fac Technology, 2026) Keser, Serhat; Kaya, Semih; Barzinjy, Azeez A.; Mahmood, Bahroz Kareem; Kareem, Rebaz Obaid; Temuz, Mehmet Mursit; Bulut, Niyazi
    In this study, hydroxyapatite (HAp) samples, co-doped with 0.44 at.% of zinc and different amount of quercetin (Zn/Que-HAp), were synthesised using a wet-chemical method and calcined at 900 degrees C. XRD shows HAp as the primary phase with minor beta-TCP. Compared to the Zn-doped sample without quercetin (Q1), quercetin co-doping induces clear structural changes (shifts of lattice parameters a from-0.0017 to +0.0006 nm and c from-0.0026 to-0.0005 nm), accompanied by changes in crystallinity (from-3.6% to +2.5%) and crystallite size (from-3.5 to +0.6 nm), evidencing a distinct co-doping effect. DTA/TGA reveal reduced total mass loss for the Que-containing compositions relative to the Zn-doped sample, indicating enhanced thermal stability of the co-doped lattice. SEM reveals granular morphologies with interconnected porosity, while EDX yields (Ca+Zn)/P ratios greater than 1.67, consistent with Ca-sufficient apatite and modified defect chemistry. DFT calculations resolve the site-specific effects of Zn substitution and predict a preference for perturbation at Ca2 sites. The electronic density of states retains a wide-gap, insulating character, with localised states sensitive to the dopant configuration. By correlating experiment and theory, we demonstrate that the organic-inorganic co-dopant pair offers an effective means to tune lattice metrics, phase balance, and thermal response without compromising the intrinsic insulating nature of HAp.
  • Küçük Resim Yok
    Öğe
    Investigation of the Structural, Thermal, Spectroscopic, and Electronic Properties of Praseodymium-based Hydroxyapatites Co-doped with Silver and Zinc in Varying Concentrations
    (Budapest Univ Technology Economics, 2025) Kareem, Rebaz Obaid; Ates, Tankut; Barzinjy, Azeez A.; Temuz, Mehmet Mursit; Ince, Turan; Bulut, Niyazi; Kaygili, Omer
    This study investigates the crystal structure, energy gap, band structure, spectroscopy, thermal, and electrical properties of Pr3+-based hydroxyapatites (HAp) co-doped with Zn2+ and Ag+ in varying concentrations. The synthesized samples, designated as 0.25Zn-0.25PrHAp, 0.50Zn-0.25Pr-HAp, 0.75Zn-0.25Pr-HAp, 0.25Ag-0.25Pr-HAp, 0.50Ag-0.25Pr-HAp, and 0.75Ag-0.25Pr-HAp, were prepared using a wet chemical method. The materials were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Additionally, theoretical calculations employing density functional theory (DFT) were conducted to analyze the band structure (BS), energy gap (Eg; EHOM & oacute;ELUMO), and density of states (DOS). Results revealed a progressive reduction in the bandgap with increasing dopant concentrations, particularly in Ag-doped samples. Notably, 0.75Ag-0.25Pr-HAp exhibited the smallest bandgap of 3.983 eV, indicating enhanced electronic conductivity and potential applications in bioelectronics and medical sensors. Furthermore, the co-doped samples demonstrated reduced crystallinity, larger crystallite sizes, and excellent stability in biological environments, alongside superior biocompatibility and antibacterial properties. Among the synthesized materials, 0.75Ag-0.25Pr-HAp exhibited promising characteristics as a biomedical material for bone-related applications, owing to its structural stability, enhanced electrical properties, and suitability in antibacterial and bioelectronic devices. This investigation highlights the versatility of Zn/Ag co-doped Pr-HAp materials for advanced biomedical and technological applications.