Yazar "Kebiroglu, Hanifi" seçeneğine göre listele

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    Effects of Yttrium Doping on Erbium-Based Hydroxyapatites: Theoretical and Experimental Study
    (Mdpi, 2022) Ahmed, Lana Omar; Bulut, Niyazi; Kebiroglu, Hanifi; Alkhedher, Mohammad; Ates, Tankut; Koytepe, Suleyman; Ates, Burhan
    This is the first investigation of yttrium (Y) and erbium (Er) co-doped hydroxyapatite (HAp) structures, conducted using theoretical and experimental procedures. By using a wet chemical method, the materials were synthesized by varying the concentration of Y amounts of 0.13, 0.26, 0.39, 0.52, 0.65, and 0.78 at.% every virtual 10 atoms of calcium, whereas Er was kept fixed at 0.39 at.%. Spectroscopic, thermal, and in vitro biocompatibility testing were performed on the generated samples. Theoretical calculations were carried out to compute the energy bandgap, density of states, and linear absorption coefficient. The effects of Y concentration on thermal, morphological, and structural parameters were investigated in detail. Raman and Infrared (FTIR) spectroscopies confirmed the formation of the HAp structure in the samples. Theoretical investigations indicated that the increasing amount of Y increased the density from 3.1724 g cm(-3) to 3.1824 g cm(-3) and decreased the bandgap energy from 4.196 eV to 4.156 eV, except for the sample containing 0.39 at. % of the dopant, which exhibited a decrease in the bandgap. The values of linear absorption appeared reduced with an increase in photon energy. The samples exhibited cell viability higher than 110%, which revealed excellent biocompatibility for biological applications of the prepared samples.
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    The effects of Zn/Fe co-dopants on the structural, thermal, magnetic, and in vitro biocompatibility properties of calcium pyrophosphate ceramics
    (Elsevier, 2022) Kebiroglu, Hanifi; Ates, Tankut; Bulut, Niyazi; Ercan, Ismail; Ercan, Filiz; Acari, Idil Karaca; Koytepe, Suleyman
    In the present work, calcium pyrophosphate (CPP) samples co-doped with Zn and Fe were prepared by using a wet chemical method, and their thermal, magnetic, structural, morphologic, and in vitro biocompatibility properties were investigated for the first time. X-ray diffraction (XRD) results showed that a continuous decreasing trend in two lattice parameters, unit cell volume, and average crystallite size was observed with the increasing Zn content. Zn content affected the magnetic and thermal behaviors, cell viability property of the CPP, as well as morphology. The sample containing 0.22 at.% Zn and 0.22 at.% Fe showed the best biocompatibility among all the samples, and the higher amount of Zn caused the lower cell viability. The bandgap of the CPP decreased with adding of Zn, while the linear absorption coefficient value increased.
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    The experimental and theoretical investigation of Sm/Mg co-doped hydroxyapatites
    (Elsevier, 2022) Hssain, Ala Hamd; Bulut, Niyazi; Ates, Tankut; Koytepe, Suleyman; Kurucay, Ali; Kebiroglu, Hanifi; Kaygili, Omer
    This study presents an extensive experimental and theoretical analysis of Mg -doped hydroxyapatite (HAp) samples with additional Sm doping at varying amounts. A wet chemical method was used to synthesize Mg-containing HAps at a constant amount of 0.133 at. %, and in addition the second dopant of Sm was utilized at varying amounts of 0.133, 0.266, 0.399, 0.532, and 0.665 at. %. All of these samples were investigated experimentally and theoretically by using the X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Raman spectroscopy, differential thermal analysis (DTA), thermogravimetric analysis (TGA), in-vitro cell viability tests, and density functional theory (DFT) calculations. The bandgap energy was found to have reduced from 4.6115 eV to 4.3870 eV. The linear attenuation (or absorption) coefficient increased as the amount of Sm in the sample increased, and this parameter decreased as the photon energy increased for all samples. Both the lattice parameter and the theoretical density increased, whereas the unit cell volume and the lattice parameters declined. The XRD and FTIR results revealed that the HAp phase (over 98 percent for all samples) was a major phase formed, while the beta -TCP phase (beta-tricalcium phosphate) was a minor phase. The beta-TCP phase increased from 0.91 to 1.57 percent with an increasing amount of Sm. The volume of the unit cell trended in the same direction as predicted by the obtained results theoretically. Increased anisotropic energy density and a decrease in crystallinity have been observed. All samples were found to be thermally stable. Due to the presence of Sm content, cell viability was observed to be affected.
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    Experimental characterization and theoretical investigation of Zn/Sm co-doped hydroxyapatites
    (Elsevier, 2022) Hssain, Ala Hamd; Bulut, Niyazi; Ates, Tankut; Koytepe, Suleyman; Kurucay, Ali; Kebiroglu, Hanifi; Kaygili, Omer
    In this study, the wet chemical method was used to synthesize Zn-doped hydroxyapatite (HAp) samples, and the effects of varying the amount of Sm addition on structural, thermal, and biocompatibility in vitro properties were studied. In addition, a density functional theory was used for modeling the as-synthesized samples to obtain the theoretical calculation results. XRD results confirmed the formation of biphasic compositions for all samples, and FTIR data supported the formation of the functional groups of hydroxyl and phosphate. More than 98% of samples showed the formation of the HAp phase. The addition of Sm resulted in an increase in the secondary phase of the beta-TCP from 0.60 % to 1.49 %. The lattice parameters (aandc), unit cell volume (V), lattice strain (epsilon), and lattice stress (sigma) varied when Sm was added as a dopant. The crystallite size and crystallinity decreased as the Sm content increased, however, the anisotropic energy density gradually increased. Thermal analysis results confirmed that all samples seemed to be thermally stable. The addition of Sm did not result in any notable morphological modifications. Cell viability values of the Zn-based HAp sharply decreased as a result of an increase in the Sm additive. Theoretical studies show that when the amount of Sm in the Zn-based HAp structure increases, the bandgap energy decreases from 4.68 to 4.40eV. An increasing density and decreasing unit cell volume have been observed, as confirmed by the theoretical results. In addition, there was a decrease in crystallinity as well as an increase in anisotropic energy density.
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    Exploring the electronic band structure, spectroscopic signatures, and structural properties of Er3+-based hydroxyapatites co-doped with Ce3+ions
    (Elsevier, 2023) Ahmed, Lana Omar; Bulut, Niyazi; Banares, Luis; Kaygili, Omer; Kebiroglu, Hanifi; Ates, Tankut; Koytepe, Suleyman
    In this work, we have investigated Ce3+ and Er3+ co-doped hydroxyapatite (HAp) structures both theoretically and experimentally for the first time. The Ce3+ content was incrementally varied in steps of 0.13 at. %, ranging from 0.13 at. % to 0.78 at. %. Meanwhile, the Er3+ content remained constant at 0.39 at. % for all samples. We employed X-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and in vitro biocompatibility tests to examine the prepared samples. Our findings demonstrate that the thermal behavior, morphology, and other crystal structure-related parameters are significantly influenced by the con-centration of Ce3+. The formation of HAp structures was confirmed through FTIR and Raman spectroscopic analyses. Furthermore, we conducted theoretical calculations to determine the linear absorption coefficient, density of states, and bandgap. These calculations revealed that the addition of Ce3+ atoms at varying concen-trations resulted in an increase in density from 3.174 to 3.195 g cm-3, while the bandgap gradually decreased from 4.16 to 4.10 eV, except for the 0.26Ce-0.39Er-HAp and 0.52Ce-0.39Er-HAp compositions, where the energy bandgap exhibited an increase.
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    Sr/Smco-doped hydroxyapatites: experimental characterization and theoretical research
    (Springer, 2022) Hssain, Ala Hamd; Bulut, Niyazi; Ates, Tankut; Koytepe, Suleyman; Kurucay, Ali; Kebiroglu, Hanifi; Kaygili, Omer
    This paper goes into extensive detail about the theoretical and experimental characterization of Sr doped hydroxyapatite (HAp) samples that have been doped with Sm in various amounts. To accomplish this, five HAps containing a constant 0.133at.% of Sr were additionally doped with Sm at varied amounts and synthesized by a method of wet chemical. In addition, the density functional theory (DFT) was used to model all of these samples. According to theoretical results, the bandgap energy declined continuously from 4.6297 to 4.4034eV. The linear absorption coefficient increased with increasing amounts of Sm in all samples, while this parameter decreased with increasing photon energy. There was a reduction in both the lattice parameter a and the volume of the unit cell, but there was also an increase in the lattice parameter c and theoretical density. Accordingly, the experiment's results were as follows:HAp phase (above 98% for all of the samples) and beta-tricalcium phosphate beta - TCP were both confirmed as the major phase and minor phase, respectively, by X-ray diffraction (XRD), FT-Raman spectroscopy and the Fourier transform infrared (FTIR) measurements. The addition of Sm increased in the beta - TCP phase from 0.62 to 0.86%. Same as theoretical results, it was also found that density was increasing and the volume of the unit cell decreased. An increase in anisotropic energy density and a decrease in crystallinity were discovered. The values are calculated based on the molar ratio, which was discovered to be close to those for stoichiometric HAp in all samples (1.67). Based on the results of the thermal study, all samples were confirmed to be thermally stable. Sm content was discovered to have an effect on cell viability.
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    Theoretical and experimental characterization of Sn-based hydroxyapatites doped with Bi
    (Springer, 2022) Korkmaz, A. Aksogan; Ahmed, Lana Omar; Kareem, Rebaz Obaid; Kebiroglu, Hanifi; Ates, Tankut; Bulut, Niyazi; Kaygili, Omer
    This is the first report, including both theoretical and experimental results, on Bi and Sn co-doped hydroxyapatite (HAp) structures. Sn content was kept at a constant amount of 0.22 at.%, and Bi content was changed from 0 to 0.44 at.% by using the steps of 0.11at.%. Theoretical results from density functional theory (DFT) calculations revealed an increase in density from 3.154 g cm(-3) to 3.179 g cm(-3), as well as gradual decreases in the bandgap from 4.5993 eV to 4.4288 eV and the linear absorption coefficient. The spectroscopic data obtained from both Raman and Fourier transform infrared (FTIR) spectra confirmed the HAp structure for all the samples. The thermal behavior and morphology, as well as all X-ray diffraction (XRD) related parameters, were all considerably impacted by Bi-content. In vitro assays showed that all the samples can be accepted as the biocompatible materials.
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    Theoretical and experimental investigation of the effects of Pr dopant on the electronic band structure, thermal, structural, in vitro biocompatibility of Er-based hydroxyapatites
    (Elsevier, 2023) Ahmed, Lana Omar; Bulut, Niyazi; Osmanlioglu, Fatih; Tatar, Beyhan; Kebiroglu, Hanifi; Ates, Tankut; Koytepe, Suleyman
    Pr and Er co-doped hydroxyapatites (HAps) have undergone their first theoretical and experimental re-search. Pr content was changed in 0.13 percent increments from 0.13 to 0.78 percent. Er content was kept constant at 0.39 at.%. Theoretical results demonstrated an increase in the density from 3.154 to 3.179 g cm -3, as well as steady decreases in the bandgap from 4.1739 to 4.0618 eV. X-ray diffraction (XRD) pat-terns point out that all the samples consist of the single phase of the HAp. The crystallinity decreased steadily with adding of Pr. Pr-content has a considerable impact on all the XRD-related parameters, ther-mal behavior and morphology. The cell viability was affected by the co-dopant content, and this value was found to be higher than 83% for all the samples. (c) 2023 Elsevier B.V. All rights reserved.