Person: ZENGİN KURT, BELMA
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Publication Metadata only The impact of Ir doping on the electrical properties of YbFe1−xIrxO3 perovskite-oxide compounds(2020-01-01T00:00:00Z) Coskun, M.; Polat, O.; Coskun, F.M.; Kurt, BELMA; Durmus, Z.; Caglar, M.; Turut, A.; ZENGİN KURT, BELMAPublication Metadata only Synthesis, DFT calculations and molecular docking study of mixed ligand metal complexes containing 4,4′-dimethyl-2,2′-bipyridyl as α-glucosidase inhibitors(2020-04-05T00:00:00Z) Avcı, Davut; Altürk, Sümeyye; Sönmez, Fatih; Tamer, Ömer; Başoğlu, Adil; Atalay, Yusuf; Kurt, BELMA; ZENGİN KURT, BELMAPublication Open Access Structural and mechanical analysis of three orthodontic adhesive composites cured with different light units(2020-04-01T00:00:00Z) YILMAZ, BERZA; BAKKAL, MELTEM; Kurt, BELMA; YILMAZ, BERZA; BAKKAL, MELTEM; ZENGİN KURT, BELMAObjective: To evaluate the effects of three different curing units on the physical and mechanical features of three different orthodontic adhesive resin materials. Material and Methods: 45 specimens (5 mm in diameter, and 2 mm in thickness) of each of the three different adhesive composite resin materials (Transbond XT, Grēngloo™ Adhesive and Light Bond Paste) were cured with three different light units (a polywave third generation (Valo), a monowave (DemiUltra), and a second-generation LED (Optima 10)). To quantify degree of conversion (DC), the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy was used in transmission mode (ALPHA FT-IR Spectrometer, Bruker Optics, Germany). Vickers hardness value was recorded under constant load 100 g for 10 s with a microhardness tester (HMV M-1, Shimadzu Corp., Kyoto, Japan). The data were statistically analyzed using Kruskal-Wallis and chi-square tests. The level of significance was considered p<0.05. Results: The highest DC values were obtained as a result of curing with Optima 10. This rate was followed by Demi Ultra and Valo, respectively. Transbond XT samples showed a lower level of conversion than the samples of Light Bond Paste and Grēngloo™ Adhesive. The top surfaces of each material showed higher hardness values than the bottom surfaces (p<0.05). The Light Bond Paste showed the highest hardness values both on the top and bottom surfaces among the three materials, followed by Grēngloo™ Adhesive. While the hardness values of the top surfaces of the samples cured with Demi Ultra and Valo light units were similar, higher hardness values are recorded with Valo on the bottom surfaces (Valo; 85.200/75.200 (top/bottom) versus Demi Ultra; 86.100/66.000 (top/bottom)). Conclusions: The different DC and the surface hardness properties were recorded for the resin as orthodontic adhesives depending on different light units. Shorter radiation time caused lower DC and surface hardness values.Publication Metadata only Preparation, antioxidant activity, and theoretical studies on the relationship between antioxidant and electronic properties of bis(thio/carbohydrazone) derivatives(2022-05-01T00:00:00Z) Muğlu, Halit; Kurt, BELMA; Sönmez, Fatih; Güzel, Emre; Çavuş, M. Serdar; Yakan, Hasan; ZENGİN KURT, BELMA© 2022 Elsevier LtdA series of novel bis(thio/carbohydrazone) compounds has been prepared from (thio)/carbohydrazide and various aldehyde derivatives. FTIR, 1H and 13C NMR spectroscopy, and elemental analysis have been used to elucidate the structures of synthesized compounds. Their antioxidant properties have been assessed using the DPPH, ABTS, and CUPRAC methods. Most of the synthesized compounds exhibited antioxidant activity in each assay. The effects of the electronic and structural properties of urea/thiourea groups on the antioxidant properties of the compounds have been investigated, and it was observed that thiourea-based compounds showed better antioxidant activity than structurally similar urea-based compounds. Among them, N′,N‴-1,4-phenylene-bis(methaneylylidene)-bis(N′-2-hydroxybenzylidene)methane-bis(thiohydrazide) (9) and N′,N‴-(1,4-phenylene-bis(methaneylylidene)-bis(N′-2,4-dihydroxybenzylidene)methane-bis(thiohydrazide) (11) showed higher ABTS activity (IC50 = 2.69 μM and 3.24 μM, respectively) than the reference butylated hydroxyanisole (BHA, IC50 = 3.42 μM). Moreover, compound 11 showed the strongest DPPH activity with an IC50 value of 5.77 μM, almost twofold higher than that of BHA (IC50 = 9.55 μM). Structural, spectral, and electronic analyses of the compounds have also been performed by DFT calculations at the B3LYP/6–311++g(2d,2p) level of theory. EDR, NCI, DOS, and QTAIM calculations have been carried out to analyze the bond properties of electronegative atoms and to investigate intramolecular interactions. DFT simulations have also been carried out in order to study the relationship between electronic characteristics and antioxidant activity.Publication Metadata only Synthesis, spectral properties, in vitro α-glucosidase inhibitory activity and quantum chemical calculations of novel mixed-ligand M(II) complexes containing 1,10-phenanthroline(2020-04-01T00:00:00Z) Avcı, Davut; Altürk, Sümeyye; Sönmez, Fatih; Tamer, Ömer; Başoğlu, Adil; Atalay, Yusuf; Kurt, BELMA; Dege, Necmi; ZENGİN KURT, BELMAPublication Metadata only Quinoline Schiff-base ligands as long-wavelength photosensitizers for diphenyliodonium salt(2020-09-01T00:00:00Z) Temel, Binnur Aydogan; Kurt, BELMA; Akar, Irem; Keklik, Merve; TEMEL, BİNNUR; ZENGİN KURT, BELMAPublication Open Access Synthesis, spectral properties, α-glucosidase inhibition, second-order and third-order NLO parameters and DFT calculations of Cr(III) and V(IV) complexes of 3-methylpicolinic acid(2020-11-15T00:00:00Z) Avcı, Davut; Altürk, Sümeyye; Sönmez, Fatih; Tamer, Ömer; Başoğlu, Adil; Atalay, Yusuf; Kurt, BELMA; Dege, Necmi; ZENGİN KURT, BELMAThe Cr(III) and V(IV) complexes of 3-methylpicolinic acid (3-mpaH) were synthesized. The XRD and LC-MS/MS were performed to determine experimental geometric structure of the synthesized complexes. Their experimental spectral analyses were carried out by FT-IR and UV-Vis spectra. Their alpha-glucosidase activities were also evaluated. The synthesized Cr(III) and V(IV) complexes exhibited alpha-glucosidase inhibitory activity with the IC50 values of >600 mu M. Furthermore, the optimal molecular structure geometries, vibrational frequencies, electronic spectral properties, refractive index, band gap, second- and third-order nonlinear optical (NLO) parameters of these complexes were obtained by using DFT/HSEh1PBE/6-311G (d,p)/LanL2DZ level. NLO results demonstrate that the complex 1 is a promising candidate to materials with the high first- and second-order hyperpolarizability values obtained at 55.3 x 10(-30) and 251.0 x 10(-36) esu in ethanol solvent. The experimental refractive index and band gap parameters were comparatively presented. Lastly, NBO analysis was fulfilled to investigate inter- and intra-molecular bonding and the definition of coordination geometries around the central metal ions, as well as the electronic charge transfer interactions in the Cr(III) and V(IV) complexes. (C) 2020 Elsevier B.V. All rights reserved.Publication Open Access Synthesis and biological evaluation of novel coumarin-chalcone derivatives containing urea moiety as potential anticancer agents(2020-01-01T00:00:00Z) Kurt, BELMA; Kandas, Nur Ozten; DAĞ, AYDAN; Sonmez, Fatih; Kucukislamoglu, Mustafa; ZENGİN KURT, BELMA; DAĞ, AYDANThe increasing interest on new drug discovery is constantly up to date as drugs do not increase survival adequately against increasing cancer cases worldwide. Based on the reported anticancer activity of coumarin, chalcone and urea derivatives, the present investigation dealt with the design and synthesis of coumarin derivatives bearing diversely substituted chalcone-urea moieties 5a-k. Through a structure-based molecular hybridization approach, a series of novel coumarin-chalcone derivatives containing urea moiety was synthesized and screened for their in vitro antiproliferative activities against the cancer cell lines (H4IIE and HepG2). In addition, the synthesized compounds were tested on a cell line that was not cancerous (CHO) and the damage, it could give to normal cells was determined. Among the synthesized compounds, 5k exhibited better inhibition of H4IIE compared to Sorafenib. 5j also showed better inhibition against HepG2 than Sorafenib. In particular, 5k induced H4IIE apoptosis, arrested cell cycle at the S phase. Therefore, 5k and 5j may be potent antitumor agents, representing a promising lead for further optimization. (C) 2017 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.Publication Metadata only Spectrofluorimetric Determination of Aflatoxin B-1 in Winter Herbal Teas via Magnetic Solid Phase Extraction Method by using Metal-Organic Framework (MOF) Hybrid Structures Anchored with Magnetic Nanoparticles(2020-01-09T00:00:00Z) Durmus, Zehra; Kurt, BELMA; GAZİOĞLU, IŞIL; SEVGİ, ECE; Hancer, Cagla Kizilarslan; ZENGİN KURT, BELMA; GAZİOĞLU, IŞIL; SEVGİ, ECE; KIZILARSLAN HANÇER, ÇAĞLAMIL53(Al)-SiO2@Fe3O4 composite was prepared by co-precipitation route with a typical Stober synthetic process and ultrasonic-agitation, then subsequently utilized as a multi-component novel sorbent in solid-phase microextraction (SPME) of aflatoxin B1 in winter herbal teas. Microstructural properties of MIL53(Al)-SiO2@Fe3O4 composite was characterized by using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) methods, and Brunauer-Emmett-Teller (BET) surface area measurement. The MIL53(Al)-SiO2@Fe3O4 composite was found to be a very effective sorbent in spectrofluorimetric determination of aflatoxin B1 (AFB1) in winter herbal teas via magnetic solid-phase extraction (SPE) route. The proposed method showed a wide linear range from 0.5 to 150 ng/ml, low limit of detection (LOD = 0.5 ng/ml), and an acceptable recovery values (70.7-96.5%) in real samples analysis. This study shows that the suggested method possesses an important potential to use for detecting AFB1 in quality control laboratories.Publication Metadata only Frequency and temperature-dependent electric modulus spectroscopy of osmium-doped YbFeO3 structure(2020-02-06T00:00:00Z) Polat, O.; COŞKUN, MUSTAFA; Kalousek, R.; Zlamal, J.; Kurt, BELMA; Caglar, Y.; Caglar, M.; TÜRÜT, ABDULMECİT; ZENGİN KURT, BELMAOrthoferrites have occupied important place in the material science and condensed matter physics investigations due to their unique features such as electrical, magnetic and optical. The present investigation illuminates light on the electrical properties of osmium (Os) doped YbFeO3 (YbFO) rare-earth orthoferrite. The undoped YbFO and YbFe1-xOsxO3 (YbFOO) (x = 0.01 and 0.05) powders were synthesized via solid-state. X-ray diffractometer (XRD) has been utilized to examine the crystal structure of the YbFO and YbFOO powders. The cross sectional morphology of the obtained pellets was inspected via scanning electron microscope (SEM). Moreover, x-ray photoelectron spectroscopy was exploited to determine the oxidation states of the constituted elements. The electrical features for instance electrical modulus, dielectric constant and conductivity of the synthesized pellets were detailed at different frequencies and temperatures by dielectric/impedance spectroscopy studies. The x = 0.01 Os doped sample exhibits higher dielectric constant and conductivity compared to other samples. Moreover, in order to explain conductivity mechanism of the studied samples, multiple conduction models are needed to employ.