Yazar "Eyupoglu, Volkan" seçeneğine göre listele

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    Biosorption of dye crystal violet on Tragopogon sp. leaf powder: Equilibrium, kinetics, thermodynamics, and DFT calculations
    (Elsevier, 2024) Eyupoglu, Volkan; Aksu, Aysun; Cetinkaya, Huseyin Fatih; Cetintas, Halil Ibrahim; Cetinkaya, Serap; Tuzun, Burak
    Crystal violet, CV, was adsorbed on dead mass of Tragopogon sp. in aqueous solutions and the adsorption process was evaluated by analytical, visual, and theoretical means. The functional groups on the biosorbent surface were detected by FT-IR (Fourier Transform Infrared Spectrophotometry), and the surface morphology was visualized by SEM (Scanning Electron Microscopy), and EDX (Energy Dispersive X-Ray Analysis). Some of the biosorption conditions, pH, time, adsorbent mass, and temperature, were optimized. Three isotherm models, Langmuir, Freundlich, and Dubinin-Radushkevich, employed for the understanding of the reaction kinetics, suggested a spontaneous endothermic reaction that took place on the surface of Tragopogon sp cells. Iterative usability experiments, involving four biosorption-desorption rounds, showed that Tragopogon sp. biomass retained approximately 42% of its sorbent activity. Calculations, using the Gaussian software packages B3LYP, HF, and M06-2x, indicated a very high biosorption capacity of Tragopogon sp. for crystal violet. Crystal violet had -7.2067 HOMO and 0.1921 LUMO values.
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    Effective removal of methylene blue dye from aqueous solution using Macrolepiota procera mushroom: Experimental and theoretical studies
    (Elsevier B.V., 2025) Eyupoglu, Volkan; Akin, Muhammed Bora; Kaya, Savaş; Çaylak, Osman; Berisha, Avni; Çetinkaya, Serap
    This study investigated Macrolepiota procera mushroom biomass as a biosorbent for removing methylene blue (MB) dye from aqueous solutions. Key adsorption parameters such as pH, biosorbent dosage, and contact time were optimized, achieving a maximum adsorption capacity of 1.404 mol·kg−1 at pH 9, with 100 mg biosorbent and a temperature of 25 °C. SEM, EDX, and FT-IR analyses characterized the biosorbent's surface morphology and functional groups. Adsorption followed the Langmuir isotherm model, showing high affinity in alkaline conditions, and efficiency increased by 90.88 % with 200 mg biosorbent. Kinetic data fit Pseudo-Second and Pseudo-First Order models, and thermodynamics indicated an endothermic, spontaneous process. Recovery tests revealed ∼ 4 % retained activity after five cycles. Density Functional Theory calculations supported experimental adsorption energies, confirming chitin's role in MB binding. © 2024 Elsevier B.V.
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    Novel Aminothiazole-Chalcone Analogs: Synthesis, Evaluation Acetylcholinesterase Activity, In Silico Analysis
    (Wiley-V C H Verlag Gmbh, 2025) Sarikaya, Meryem Kececi; Yildirim, Suheda; Kocyigit, Umit M.; Ceylan, Mustafa; Yirtici, Umit; Eyupoglu, Volkan
    In this study, novel thiazole-chalcone analogs were synthesized, and their inhibitory effects on acetylcholinesterase (AChE) were examined. In vitro enzyme activity studies were conducted to calculate IC50 values, which were found to range between 2.55 and 72.78 mu M (tacrine IC50 = 53.31 mu M). The Ki values of the compounds showing the best inhibition (6g and 6e) were calculated and compared to those of the standard substance tacrine. All compounds reduced the AChE activity. Additionally, predictions made with SwissADME indicated that all compounds complied with Lipinski's rules and possessed good oral bioavailability properties, and the inhibitory effects of compounds 6e and 6g on AChE were evaluated using molecular docking and molecular dynamics simulations (100 ns). The results showed that compounds 6e and 6g had strong and stable interactions with AChE.
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    Removal of Erythrosine B dye from wastewater by Penicillium italicum: experimental, DFT, and molecular docking studies
    (Taylor Francis, 8.03.2023) Çetinkaya, Serap; Eyupoglu, Volkan; Çetintaş, Halil İbrahim; Yenidünya, Ali Fazıl; Kebabcı, Özgür; Tüzün, Burak
    The study involved the adsorption of Erythrosine B onto the dead, dry, and unmodified Penicillium italicum cells and the analytical, visual, theoretical assessment of the adsorbent-adsorbate interactions. It also included desorption studies and reiterative usability of the adsorbent. The fungus was a local isolate and it was identified by partial proteomic experiment in a MALDI-TOFF mass spectrometer. Chemical features of the adsorbent surface were analysed by FT-IR and EDX. Surface topology was visualized by SEM. Isotherm parameters of the adsorption were determined by using three most frequently used models. Erythrosine B appeared to form a monolayer onto the biosorbent and some of the dye molecules could have also penetrated into the adsorbent particles. Kinetic results suggested a spontaneous and exothermic reaction taken place between the dye molecules and the biomaterial. Theoretical approach involved the determination of some of the quantum parameters as well as the toxic or drug potentials of the some of the components of the biomaterial.