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Öğe Bioactive contents, In vitro antiradical, antimicrobial and cytotoxic properties of rhubarb (Rheum ribes L.) extracts(Taylor & Francis Ltd, 2020) Keser, Serhat; Keser, Fatma; Karatepe, Mustafa; Kaygili, Omer; Tekin, Suat; Turkoglu, Ismail; Demir, ErsinRheum ribes L. (rhubarb) is belonging to Polygonaceae, and its roots and fresh shoots are consumed as vegetable in Turkey. This plant is considered to be one of the most important pharmaceutical raw materials in Middle East. In this study, the antiradical, antimicrobial, cytotoxic and bioactive properties of water, ethanol, and methanol extracts of R. ribes stems were determined. R. ribes stems water, ethanol and methanol extracts are better scavenged ABTS(center dot+) (99.27, 99.91, and 99.88%), DPPH center dot (83.11, 81.42, and 83.26%), and OH center dot radicals (93.49, 94.21, 95.86%) than standard antioxidant BHA (95.32, 80.49, and 93.78%). Stems of R. ribes abundantly include bioactive compounds, dominated by rutin, catechin, caffeic acid, ferulic acid, alpha-tocopherol and vitamin D. These extracts show effective cytotoxic properties against PC-3, A2780, HCT-116 and MCF-7 cancer cell lines at 24h. It is found that R. ribes contain high amount important bioactive contents, and has effective antiradical and cytotoxic properties.Öğe Ce/Sm co-doped hydroxyapatites: synthesis, characterization, and band structure calculation(Springer, 2021) Kaygili, Omer; Vural, Gulay; Keser, Serhat; Yahia, I. S.; Bulut, Niyazi; Ates, Tankut; Koytepe, SuleymanIn this paper, Ce/Sm co-doped hydroxyapatites (HAps) were synthesized by a wet chemical route. The amount of Ce was kept at constant at the value of at.% 0.4, and the second dopant of Sm was used at different amounts of at.% 0, 0.6, 1.2, and 1.8, respectively. The effects of these co-dopants on the crystal structure, morphology, and thermal properties of HAp were determined experimentally using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Furthermore, the band structure of the prepared samples was modeled theoretically using the quantum calculations of the density of states and band structure. A gradual increase from 26.56 to 36.23 nm in the crystallite size was observed. Although the amounts of the co-dopants of Ce and Sm did not affect the thermal stability and microstructure of HAp, its crystal structure-related parameters were affected by the amount of these co-additives. The partial substitution of both co-dopants was detected. The 0.4Ce-1.2Sm-HAp sample may be considered as the best crystal structure with a steady-state. It was seen that the band structure and density of states were also affected by these co-dopants. The bandgap value decreased gradually from 4.6078 to 4.0477 eV due to these dopants.Öğe Co Katkılı SnO2 Numunelerinin Sentez ve Karakterizasyonu(2020) Ateş, Tankut; Kaygılı, Ömer; Bulut, Niyazi; Okur, Havva Esma; Keser, Serhat; Yahıa, I.S.; Köytepe, SüleymanYüksek kristalleşmeye sahip katkısız ve Co katkılı SnO2 numuneleri başarılı bir biçimde hazırlandı. Coiçeriğinin SnO2’nin termal ve morfolojik özellikleri üzerine etkileri araştırıldı. Co ilavesiyle Kristalbüyüklüğünde ve birim hücre parametrelerinde değişimler tespit edildi. Co ilavesiyle faz bileşimi değişmedi.Hem X-ışını kırınımı hem de Fourier dönüşümlü kızılötesi sonuçları her bir numune için SnO2 fazınınoluşumunu doğruladı. Üretilen numunelerin oda sıcaklığından 900 °C’ye kadar termal kararlılığı gözlendi.Morfoloji Co içeriğinden etkilendi ve enerji dağılımlı X-ışını sonuçları SnO2 yapısı içerisine Co’ın nüfuz ettiğinidoğruladı.Öğe Cytotoxic effect of endemic Tchihatchewia isatidea Boiss. from Turkey(Brill, 2021) Kirbag, Sevda; Keser, Serhat; Tekin, Suat; Inci, Sule; Sandal, SuleymanTchihatchewia isatidea Boiss (Brassicaceae) is known among the public as Reddish Bride, Paint and Bridal Flower. Flower parts are used for painting and flowering branches for treatment of cough. In this study, anticancer properties of water, ethanol and methanol extracts of Tchihatch-ewia isatidea flower parts were investigated against human breast (MCF-7), human colon (HCT-116) and human prostate (LNCaP) cancer cell lines. Changes in the viability of cancer cells were de-tected by utilizing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Studies have shown that there is a statistically significant decrease in the cell viability of human breast cancer (MCF-7), colon (HCT-116) and prostate (LNCaP) cancer cells when extracts of T. isati-dea water, ethanol and methanol are used.Öğe Determination of Anticancer and Antimicrobial Properties of Alcea calvertii(Wiley-Blackwell, 2016) Keser, Serhat; Tekin, Suat; Kaygili, Omer; Keser, Fatma; Turkoglu, Ismail; Turkoglu, Semra; Kirbag, Sevda[Abstract Not Available]Öğe The Effect of Hypericum scabrum on the Human Prostate, Colon and Breast Cancer(Wiley-Blackwell, 2016) Keser, Serhat; Tekin, Suat; Kaygili, Omer; Keser, Fatma; Sandal, Suleyman[Abstract Not Available]Öğe Effects of gallic acid and quercetin on the structural, thermal, spectroscopic, in vitro biocompatibility and electronic properties of Au-based hydroxyapatite structure(Elsevier Science Sa, 2024) Keser, Serhat; Dogan, Ahmet; Ates, Tankut; Barzinjy, Azeez A.; Ates, Burhan; Tekin, Suat; Sandal, SuleymanThe aim of this study is investigating the structural, thermal, spectroscopic, electronic and biocompatibility properties of the Au-based hydroxyapatites containing quercetin (Q) or gallic acid (GA) at various concentration. Different characterization techniques including; XRD analysis, FTIR and Raman spectroscopies, differential thermal analysis, SEM and EDX analysis were utilized. Cell cytotoxicity test was conducted with the cells of MG63 human bone cancer, hFOB 1.19 human osteoblast and Caco-2 human colon cancer. It has been shown that the utilized samples had no cytotoxic activity on the L-929, hFOB 1.19 and MG-63 cells. However, these samples had cytotoxic activity on Caco-2. The current study showed that the bandgap of the un-doped HAp structure was 4.976 eV. The crystallite size is also affected by Au-doping, type of the as-used biological additive and its amount. Also, the as-produced samples were thermally stable in the range from room temperature to 1000 degrees C. The particle size distributions of the samples were found at variable ranges. The molar ratios were close to the stoichiometric value of 1.667. These novel findings not only expand our appreciation for the role of dopants in materials science but also opens avenues for deliberate engineering of electronic properties for enhanced performance in various applications.Öğe The effects of gamma irradiation on dielectric properties of Ag/Gd co-doped hydroxyapatites(Springer, 2019) Kaygili, Omer; Keser, Serhat; Selcuk, A. Birkan; Bulut, Niyazi; Koytepe, Suleyman; Yahia, I. S.; Ates, Tankut1.0 at% Ag-containing hydroxyapatites (HAps) doped with the different amounts of Gd (e.g., 0, 0.8, 1.6 and 2.4 at%) were synthesized by a wet chemical method and their dielectric properties were investigated before and after gamma irradiation. The changes in the relative permittivity and alternating current (AC) conductivity values of the as-synthesized samples before and after irradiation were investigated using dielectric measurements. It was found that both Gd content and gamma irradiation dose significantly affect the dielectric properties and AC conductivity. It was concluded that especially due to the thermal stabilities and suitable dielectric properties, the as-synthesized Gd-doped Ag containing HAps could be used for bone healing applications.Öğe Effects of pyrocatechol on the computational, structural, spectroscopic and thermal properties of silver-modified hydroxyapatite(Springer, 2025) Keser, Serhat; Yildiz, Aykut; Barzinjy, Azeez A.; Kareem, Rebaz Obaid; Mahmood, Bahroz Kareem; Agid, Riyadh Saeed; Ates, TankutThis study investigates the synthesis and characterization of hydroxyapatite (HAp) ceramic biomaterials doped with silver (Ag) and pyrocatechol. HAp, commonly utilized in the treatment of hard tissues including teeth and bones, was produced and analyzed to assess the structural, morphological, elemental, and thermal properties of the materials. The phase and crystal structures of the synthesized HAp biomaterials were examined using X-ray diffraction (XRD), revealing that the incorporation of Ag and pyrocatechol influenced the crystallinity and lattice parameters. Fourier transform infrared (FT-IR) spectroscopy verified the presence of the characteristic OH- and PO4(3)(-) groups of HAp, while scanning electron microscopy (SEM) displayed consistent morphologies across all samples, free of residues or impurities. Elemental compositions were determined by energy dispersive X-ray (EDX) spectroscopy, and thermal stability was assessed through differential thermal analysis (DTA) and thermogravimetric analysis (TGA). Additionally, computational studies using density functional theory (DFT) were conducted to further investigate the electronic and structural properties of 0.44% Ag-doped HAp. The DFT calculations revealed that Ag atoms replace calcium (Ca1 and Ca2) positions in the lattice, leading to slight distortions in the lattice structure and changes in the electronic density distribution. Minor changes were observed in the band structure and electronic properties, indicating the stability and tunability of the doped system. A small amount of beta-tricalcium phosphate (beta-TCP) phase was also detected alongside the main HAp phase. These results underscore the importance of incorporating pyrocatechol and silver doping into HAp for biomedical applications. The resulting biomaterials exhibit enhanced structural, thermal, and electronic properties, with improved biocompatibility and antimicrobial activity.Öğe Experimental and theoretical characterization of Dy-doped hydroxyapatites(Springer, 2023) Isen, Fatih; Kaygili, Omer; Bulut, Niyazi; Ates, Tankut; Osmanlioglu, Fatih; Keser, Serhat; Tatar, BeyhanThe effects of adding Dy to the hydroxyapatite (HAp) structure were investigated experimentally and theoretically. The as-obtained experimental results with an increasing amount of Dy are as follows. X-ray diffraction, Raman, and Fourier transform infrared measurements verified the HAp structure for each specimen. The crystallinity, lattice parameters, lattice stress, strain, and anisotropic energy density were affected. Thermal stability and stoichiometry were not affected. It was observed that all the Dy-doped HAps have smaller crystallite size values compared to the un-doped HAp. The cell viability obtained from mouse fibroblast cell (L929) was higher than 82%, indicating all the samples were biocompatible. The theoretical findings, obtained from the density functional theory (DFT) calculations, exhibited a continuous decrease in the bandgap from 4.7109 to 3.7982 eV, an increase in the density from 3,155 to 3,189 kg m(-3), and an increase in the linear absorption coefficient.Öğe An experimental and theoretical investigation of the structure of synthesized ZnO powder(Elsevier Science Bv, 2018) Kaygili, Omer; Ercan, Ismail; Ates, Tankut; Keser, Serhat; Orek, Cahit; Gunduz, Bayram; Seckin, TurgayZnO powder has been synthesized, characterized experimentally and its theoretical modeling carried out by density functional theory (DFT). The experimental and theoretical results were compared with each other and with the available data in the literature. A detailed crystal structure analysis was carried out using X-ray diffraction (XRD) data. Experimental and theoretical FTIR analysis, energy gap and density of states and electronic band structure calculations have been done for a complete characterization of the material. The surface morphology has been investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. It has been found that the electron excitation of ZnO can occur most probably at the Gamma-Gamma point, where the energy gap has the lowest value between the valance and conduction bands.Öğe Fe ve Ti katkılı Çift Fazlı Kalsiyum Fosfatların Sentez ve Karakterizasyonu(2021) Ateş, Tankut; İnce, Turan; Kaygılı, Ömer; Keser, Serhat; Köytepe, Süleyman; Acar, Serdar; Bulut, NiyaziBu çalışmada, Ti katkısının Fe esaslı çift fazlı kalsiyum fosfat malzemelerinin yapısal, morfolojik ve termal özellikleri üzerine etkileri araştırılmıştır. X-ışını kırınımı (XRD) analizi, üretilen numunelerin hem hidroksiapatit (HAp) hem de beta trikalsiyum fosfat (?-TCP) fazlarına sahip olduğunu doğrulamaktadır. Ayrıca, Ti katkısındaki artışla ?-TCP fazının miktarının arttığı görülmektedir. Fourier dönüşümlü kızılötesi (FTIR)spektroskopisi sonuçları, numunelerdeki karakteristik fonksiyonel grupların varlığını doğrulamaktadır. Ti miktarı morfolojiyi etkilemektedir. Numunelerin ısıl davranışları birbirine benzerdir ve oda sıcaklığından 1000 °C’ye kadar tüm numuneler termal olarak kararlıdırlar. Bu sıcaklık aralığında numunelerdeki kütle kayıpları % 1,63’e eşit veya altındadır.Öğe Impact of pyrocatechol on the structural, spectroscopic, thermal characteristics, and in vitro bioactivity of gadolinium-enhanced hydroxyapatites(Elsevier, 2025) Keser, Serhat; Demirbilek, Fatos; Barzinjy, Azeez A.; Kareem, Rebaz Obaid; Mahmood, Bahroz Kareem; Ates, Tankut; Ates, BurhanIn this study, the effects of pyrocatechol content on the structural, thermal, spectroscopic, and biocompatibility properties of gadolinium (Gd) based hydroxyapatites (HAs) were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, differential thermal analysis, thermogravimetric analysis, and scanning electron microscopy. The results, of this study, show that the energy bandgap (Egap) of Gd-doped HAs decreases to 4.1978 eV, indicating a narrowing of the electronic energy levels compared to pure HAs. The doping of Gd3+ further enhances these effects, as confirmed by enhanced photoluminescence intensity attributed to cooperative energy transfer mechanisms between the dopants. The two most biocompatible materials in the HAs series were determined as 0.42Gd-HA (94%) and P16-0.42Gd-HA (91%). These results demonstrate that even small concentrations of dopant like Gd can meaningfully impact the material's electronic and optical properties, offering potential for its application in areas where a higher bandgap and insulating properties are essential, such as in biomedical implants, coatings, or electronic insulators.Öğe Impact of quercetin and gallic acid on the electronic, structural, spectroscopic, thermal properties and in vitro bioactivity of silver-modified hydroxyapatite(Elsevier Science Sa, 2025) Keser, Serhat; Firat, Melikehatun; Barzinjy, Azeez A.; Kareem, Rebaz Obaid; Ates, Tankut; Ates, Burhan; Tekin, SuatHydroxyapatite (HAp) possesses outstanding characteristics, for instance biocompatibility and osteoconductivity, which are vital for bone reconstruction. Nevertheless, it remains passive against infectious bacteria that can cultivate in compromised bone tissue, and its usage in some individuals under care might result in some objectionable provocative responses. Gallic acid (GA) and quercetin (Que) are recognised for their explicit biological activites. Connecting these properties with silver-modified HAp is remarkably interesting. The current study examined the preparation of un-doped HAp and Ag-based samples in the presence of various extents of GA and Que using the neutralization method at room temperature. The impact of GA and Que on the electronic, structural, thermal, spectroscopic, and biocompatibility properties of HAp and Ag-modified HAp were investigated intensively. Also, mouse fibroblast (L929), human osteoblast (hFOB 1.19), human bone cancer (MG-63) and human colon cancer (Caco-2) cell lines obtained from the ATCC were used for cytotoxic and biocompatibility assays. The bandgap of the distinct regions (occupation of Ca(I) and Ca(II) sites) using DFT were 3.837 and 4.211 eV, respectively. This study showed that introducing Ag as a dopant reduced the bandgap dramatically. X-ray diffraction analysis revealed that the as-prepared samples possess polycrystalline structure. While, the lattice parameters and volume of the unit cell were increased after adding Ag as a dopant. However, both GA and Que containing samples, remarkably decrease these parameters. Both FTIR and Raman spectroscopy utilized to investigate the nature of bonding structure for the utilized samples. It has been shown that the addition of Ag into the HAp causes an increase in the specific heat capacity. SEM images and EDX analysis confirm the distribution of the utilized elements and the purity of the samples. Overall, the prepared Ag-HAp/GA and Ag-HAp/Que samples offered structural and chemical characteristics close to those of ordinary bone that make them a good candidate for bone tissue regeneration.Öğe In vitro Antiradical, Antimicrobial and Antiproliferative Activities and Phytochemical Compositions of Endemic Alcea calvertii (Boiss) Boiss. Flowers(2020) Keser, Serhat; Keser, Fatma; Tekin, Suat; Kaygılı, Ömer; Turkoglu, Ismail; Demır, Ersin; Karatepe, Mustafa; Kırbağ, Sevda; Yılmaz, Okkes; Sandal, Suleyman; Turkoglu, SemraAbstract: Alcea calvertii (Boiss) Boiss. is belonged to Malvaceae family, and it is a perennial herbaceous endemic plant. Alcea genus plants are grown as ornamental plants in the gardens. In the present study, the antiproliferative, antimicrobial, antiradical activities and phytochemical compositions of ethanol, water, methanol and acet one extracts of A. calvertii flowers were examined. A. calvertii flowers water, ethanol, methanol and acetone extracts are lower scavenged DPPH, ABTS and OH radicals than standard antioxidant trolox. A. calvertii flowers contain vitamins, sterols, flavonoids and phenolic acids, dominated by vanillic acid, gallic acid, catechin, ?-tocopherol, ergosterol and vitamin D. A. calvertii flowers water extract showed better antiproliferative activities than other extracts against to MCF-7 and HCT-116 cell lines. A. calvertii flowers methanol extract showed higher antiproliferative effect against to LNCaP cell lines.Öğe In Vitro Biological Evaluation and Phytochemical Contents of Three Centaurea L. Species Growing from Eastern Anatolia in Turkey(2020) Keser, Serhat; Keser, Fatma; Turkoglu, Ismail; Kaygılı, Ömer; Tekin, Suat; Demır, Ersin; Karatepe, Mustafa; Yılmaz, Ökkeş; Kırbağ, Sevda; Sandal, Suleyman; Turkoglu, SemraAbstract: Centaurea L. species were used as medicinal plants among the people for treatment of the common cold, abscesses, peptic ulcers, hemorrhoid and diabetes etc.. In the present study, antiradical properties, phytochemical contents, antimicrobial and antiproliferative activities of three Centaurea species were investigated. Centaurea saligna (K.Koch) Wagenitz methanol (99.94%), Centaurea virgata Lam. methanol (98.23%) and water (98.10%) extracts were showed higher ABTS scavenging than trolox (96.79%). Centaurea kurdica Reichardt extracts showed lower activity than trolox for all the antiradical assays. Centaurea extracts exhibited antimicrobial activity against to some microorganisms. It was determined that these Centaurea species contain high amount of total flavonoid, phenolic and proanthocyanidin, phenolic acids, phytosterols and unsaturated fatty acids. Also, three Centaurea extracts showed very high antiproliferative property on LNCaP, HCT-116, MCF-7 cancer cell lines.Öğe Investigation of Antiproliferative Properties of Malva neglecta Extracts(Wiley, 2017) Tekin, Suat; Keser, Serhat; Keser, Fatma; Sandal, Suleyman; Turkoglu, Ismail; Karatepe, Mustafa; Turkoglu, Semra[Abstract Not Available]Öğe Investigation of The Anticarcinogenic Effects of Portulaca oleracea Extracts on Different Human Cancer Cell Lines(Wiley, 2017) Sandal, Suleyman; Keser, Serhat; Tekin, Suat; Keser, Fatma; Turkoglu, Ismail; Karatepe, Mustafa[Abstract Not Available]Öğe Investigation of the structural and thermal properties of Y, Ag and Ce-assisted SiO2-Na2O-CaO-P2O5-based glasses derived by sol-gel method(Springer, 2017) Kaygili, Omer; Keser, Serhat; Tatar, Cengiz; Koytepe, Suleyman; Ates, TankutA glass with the composition of the SiO2-Na2O-CaO-P2O5 was synthesized by sol-gel method at temperature of 900 A degrees C, and then yttrium-, silver- and cerium-containing glasses were prepared at the same conditions using this base system. The structural and thermal properties of the glass samples were investigated by X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy-dispersive X-ray (EDX) spectroscopy and differential thermal analysis techniques. The Ca-5(PO4)(2)(SiO4)(6) phase having the orthorhombic crystal system is detected for each sample without any secondary phase, and this phase is confirmed by the FTIR spectra. With the addition of Y, Ag and Ce to the SiO2-Na2O-CaO-P2O5 system, the variations in the average crystallite size, crystallinity percent, lattice parameters and unit cell volume are observed. A decrease in the crystallization peak temperature and the changes in the glass transition temperature are seen with the addition of Y, Ag and Ce to the base system. The addition of Y, Ag and Ce to the base glass increases significantly its density. The EDX spectra of the as-prepared samples verify the introduction of the as-mentioned elements.Öğe Investigation of the structural, thermal, magnetic and cell viability properties of Ce/Sr co-doped hydroxyapatites(Elsevier, 2023) Ates, Hulya Gunes; Kaygili, Omer; Bulut, Niyazi; Osmanlioglu, Fatih; Keser, Serhat; Tatar, Beyhan; Mahmood, Bahroz KareemThe present study aims to give a more detailed report on the structural, thermal, magnetic and in vitro cell viability properties of the hydroxyapatites (HAps) co-doped with Sr and Ce at different amounts. Besides these experimental analyses, this study also includes the theoretical calculation results obtained from the modeled systems for the as-prepared samples. Diamagnetic behavior was observed for all the samples, as well as their high cell compatibilities. All the samples showed a thermally stable behavior, and the mass change mechanism and specific heat capacity were affected by the amount of the codopants. The bandgap value and linear absorption coefficient varied with the amount of both co-dopants. (c) 2023 Elsevier B.V. All rights reserved.
