Araştırmacılar(7)

• Bahadir, Murat
• Das, Mehmet
• Demirpolat, Ahmet Beyzade
• Firat, Ilker
• Mazlum, Yusuf
• Ozleyen, Umit
• Yavuz, Sevtap Caglar

• ArticleYalnız künye2026/r/ebyu/11482
  Removal of Malachite Green from Aqueous Solutions by Using Bi4V2O11 Nanosheet

  Yavuz, Emre; Dundar, Ozan Ali; Yavuz, Sevtap Caglar; Yilmaz, Erkan; Ozdokur, Kemal Volkan; Cirak, Burcu Bozkurt; Caglar, Bulent; Cirak, Cagri; Arar, Özgür

  Introduction: Transition metal oxides are highly effective for dye removal due to their adaptable surface chemistry, availability, and robust mechanical and thermal properties. Among them, Bi4V2O11 nanosheets offer potential due to their morphology and high surface area. To synthesize Bi4V2O11 nanosheets and evaluate their performance in removing malachite green, focusing on the impact of adsorbent amount, contact time, and interfering ions on dye removal efficiency. This study aims to evaluate the performance of Bi4V2O11 nanosheets in removing malachite green dye from aqueous solutions and to examine the effects of adsorbent dosage, contact time, and the presence of coexisting ions on the sorption process. Methods: Bi4V2O11 nanosheets were synthesized and used to remove the malachite green dye. Batch experiments were conducted to study the effects of adsorbent dose, contact time, and coexisting ions (Na+, Ca2+, and tannic acid). Equilibrium data were fitted to the Langmuir isotherm model to determine the maximum sorption capacity. Results: Malachite green sorption using Bi4V2O11 nanosheets reached equilibrium within 240 minutes, demonstrating efficient dye removal under the tested conditions. The sorption process conformed to the Langmuir isotherm model, indicating monolayer adsorption with a maximum capacity of 47.27 mg/g. While the presence of Na+ and tannic acid had negligible effects on dye removal efficiency, the coexistence of Ca2+ significantly reduced the removal efficiency from 95% to 58%, highlighting the potential impact of divalent ions on the adsorption process. Discussion: Bi4V2O11 nanosheets are effective adsorbents for malachite green removal, demonstrating high sorption capacity and resilience to Na+ and tannic acid interference. However, the presence of Ca2+ significantly reduces removal efficiency, highlighting the need for further optimization in practical applications. Conclusion: Bi4V2O11 nanosheets offer high sorption capacity and structural stability, environment friendly synthesis procedure, making them feasible for small-scale or pre-treatment applications. 2026, Bentham Science Publishers

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• ArticleYalnız künye2026/r/ebyu/10607
  ZnBi2O4/Ag2WO4 nanocomposite for efficient photocatalytic removal of dye and pharmaceutical pollutants

  Yavuz, Sevtap Caglar; Emul, Zeynep; Icer, Fatih; Yavuz, Emre; Ozdokur, Volkan Kemal; Cirak, Burcu Bozkurt

  This paper targets to synthesize a nano-composite with high photocatalytic performance and research the possibility of utilizing it for dye and drug removal from wastewater. Herein, ZnBi2O4/Ag2WO4 nanocomposite photocatalyst was successfully synthesized via two step hydrothermal/precipitation method. The photocatalytic activity of the synthesized nanocomposite was evaluated by its effect on the degradation of methylene blue dye and sulfamerazine drug under UV light. The results revealed that the ZnBi2O4/Ag2WO4 nanocomposite achieved a significantly higher photocatalytic efficiency (96% degradation of methylene blue in 1 h) compared to ZnBi2O4 (41%) and Ag2WO4 (76%) within only 60 min. The exceptional photocatalytic degradation efficiency of the ZnBi2O4/Ag2WO4 nanocomposite against methylene blue and sulfamerazine can be attributed to the effects of reduced charge carrier recombination resulting from the synergistic effect of surface adsorption-photocatalytic degradation interaction of ZnBi2O4 and Ag2WO4.

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• ArticleYayıncıda açık erişim2025/r/ebyu/19352
  Effects of rectangular-shaped turbulators on heat transfer, friction factors, and entropy

  Fırat, İlker

  In this study, the effects of turbulators with different P ratios placed in a circular cross-section test pipe under turbulent flow conditions using water as the working fluid on heat transfer, friction factor (f), and entropy production were investigated using Ansys-Fluent 2021. The lowest Nu was calculated as 111 at Re=11825 for P=6, while the highest Nu was calculated as 219 at Re=19133 for P=1. The increase in Nu values for P = 6, 3, 2, 1.5, 1.2, and 1 compared to the plain pipe is 10.34%-11.64%; 17.39%-18.78%; 25.31%-26.56%; 34.42%-35.88%; 43.53%-44.87%; and 50.36%-51.47%, respectively. In turbulent situations, the highest entropy production rate was found to be 0.3631 W/mK at Re=11825 for P=6, while the lowest entropy production rate was found to be 0.2215 W/mK at Re=19133 for P=1. The minimum and maximum Ns reduction compared to the empty pipe was calculated as 7.13% for Re=19133 at P=6 and 46.62% for Re=11825 at P=1, respectively. In turbulent conditions, the highest Bejan number was found to be 0.9931 at Re=11825 for P=6. As a result, it was concluded that a ratio of P=1 provides maximum benefit in terms of heat transfer, while a ratio of P=6 is ideal in terms of total entropy production.

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• ArticleYayıncıda açık erişim2025/r/ebyu/11912
  EXPERIMENTAL INVESTIGATION OF THERMAL PERFORMANCE AND ENTROPY ANALYSIS OF SPHERE TURBULATORS

  KARAKUS, Taha Resul; FIRAT, Ilker; YILDIRIM, Orhan; SONMEZ, Fatin; KOCALI, Sevinc Sevgi CICEK; YILDIZ, Abdussamed; KARAGOZ, Sendogan; COMAKLI, Omer

  In this study, the effects of different numbers of sphere turbulators placed in a cir-cular-shaped test pipe under turbulent flow conditions on heat transfer, friction factor, thermal performance factor and entropy production were experimentally investigated. Water was used as the working fluid in the experiments carried out in the number range Re = 8379-16701. Initially, plain pipe and supported plain pipe experiments were carried out by keeping the fluid inlet temperature and test pipe surface temperature constant. Then, 1, 2, and 3 sphere turbulator experiments were carried out under the same conditions, respectively. According to the find-ings, the maximum Nusselt number increase compared to the supported plain pipe was 83.34% for the test pipe with 3 sphere turbulators. The minimum and maxi-mum Nu number increase rates of 3 sphere turbulators compared to 1 and 2 sphere turbulators were obtained as 42.61%-46.93% and 13.99%-17.11%, respectively. The increase rates of maximum friction factors of 1, 2, and 3 sphere turbulators compared to the supported plain pipe were 174.42%, 226.70%, and 306.53%, re-spectively. In addition, the maximum total entropy rate for sphere turbulators was obtained as 0.058 W/mK for 1 sphere turbulator at Re = 8379. In terms of the sec-ond law, the maximum entropy generation of sphere turbulators compared to the supported plain pipe decreased by 79.39% for 3 sphere turbulators at Re = 8379. As a result, it was concluded that the optimum number of sphere turbulators is 3 sphere turbulators with the lowest entropy production number and the highest ther-mal performance factor value (1.28).

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• ArticleYalnız künye2025/r/ebyu/11874
  Quantum Chemical Calculation, Molecular Docking, and Biological Activity Properties of Imidazole, Pyrimidine, and Diazepine Based Compounds

  Akkoc, Senem; Çağlar-Yavuz, Sevtap; Türkmenoğlu, Burçin; Tuğrul Zeyrek, Celal; Ilhan, Ilhan Ozer; Alhag, Sadeq K.; Al-Shuraym, Laila A.

  In this study, seven known compounds (5a–g) were tested towards four human cancer cell lines including DLD-1, HepG2, MDA-MB-231, and MCF-7 for 48 h. In addition, all compounds were also tested in a normal human cell line (Wl-38). The results showed that a compound 5e in particular had cytotoxic effects in DLD-1, HepG2, and MCF-7. The molecular modeled structures of seven investigated compounds 5a–g in the ground state were optimized using density functional theory (DFT). The chemical parameters were determined by DFT calculations. HOMOs and LUMOs of 5a–g were revealed to provide a reasonable qualitative indication of their excitation properties. To support experimental studies, compounds (5a, 5c, and 5e) with anticancer effects were interacted with epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor 2 (VEGFR-2), which were determined as possible targets. As a result of these interactions, binding parameter values (docking score, Glide e-model, Glide energy) between ligand and target were calculated.

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• ArticleYalnız künye2025/r/ebyu/11681
  Superior photocatalytic performance of ZnMoO4/Ag2WO4 for degradation of trimethoprim and methylene blue

  Yavuz, Sevtap Caglar; Yavuz, Emre; Ozdokur, Kemal Volkan

  In the present work, ZnMoO4/Ag2WO4 nanocomposite was synthesized via facile hydrothermal and chemical precipitation method for determination of photocatalytic performance on organic contaminants such as methylene blue and trimethoprim. The synthesized nano-photocatalyst was characterized using various instrumental techniques. Photocatalytic degradation of methylene blue and trimethoprim by the samples was realized under UV light irradiation. The obtained results demonstrated that photocatalytic degradation of methylene blue by ZnMoO4/Ag2WO4 was 99.6% in 30 min. The bare ZnMoO4 produced 57.8% and Ag2WO4 produced 76.7% photocatalytic degradation of methylene blue in 60 min. The synthesized ZnMoO4/Ag2WO4 nanocomposite, about which there is little information on remediation of organic pollutants, had possessed the outstanding photocatalytic degradation performance on methylene blue and trimethoprim due to pseudo first order kinetic.

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• ArticleYalnız künye2025/r/ebyu/11401
  Single-Phase Blood Flow in a Stenosed Coronary Artery: A Clinical Model-Based Experimental and Numerical Study

  Yildirim, Orhan; Karagoz, Sendogan; Sonmez, Fatin; Firat, Ilker

  This study aims to develop an experimental platform that emulates the human cardiovascular system to investigate the effects of varying pulse rates and fluid properties on pressure drop, peristaltic pump output pressure, and power consumption. To support the experimental findings, computational fluid dynamics (CFD) simulations were conducted to analyze single-phase blood flow dynamics. Idealized arterial geometries representing healthy (0% stenosis) and diseased (65% stenosis) conditions were reconstructed from computed tomography (CT) images. A non-Newtonian blood-mimicking fluid (XSCN) was formulated to better replicate the rheological behavior of blood, while distilled water was used as the Newtonian reference fluid. Experiments were conducted at six different pulse rates: 72, 84, 96, 114, 132, and 156 beats per minute (bpm). The experimental setup was replicated in a virtual environment using ANSYS Fluent to simulate flow behavior under identical boundary conditions. The results demonstrate that increasing pulse rate leads to an increase in pressure drop (ΔP), pump output pressure, and power consumption for both arterial models. These effects were more pronounced in the stenosed artery due to flow constriction. Elevated turbulence intensity was observed at higher pulse rates, with notable differences between Newtonian and non-Newtonian fluids, particularly in terms of flow resistance and shear-dependent viscosity. Power consumption was found to be directly correlated with fluid viscosity, which varied with shear rate in the non-Newtonian fluid. The 65% stenosed model consistently exhibited higher pressure drops and flow irregularities. Fractional flow reserve (FFR) analysis confirmed that a 65% luminal narrowing poses significant hemodynamic risk. The highest wall shear stress (WSS) values were localized in the stenotic region, contributing to disturbed flow patterns and increased turbulence downstream. The non-Newtonian fluid model revealed that WSS was more sensitive to flow alterations, emphasizing the role of shear-dependent viscosity in vascular hemodynamics. These findings underscore the critical influence of hemodynamic parameters—such as pulse rate, viscosity, and arterial geometry—on cardiovascular performance. The study further highlights the detrimental impact of arterial stenosis on blood flow behavior and energy expenditure, with implications for clinical diagnosis and treatment planning in cardiovascular diseases.

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• ArticleYayıncıda açık erişim2024/r/ebyu/19092
  Quantum Chemical Computations, Molecular Docking, and ADMET Predictions of Cynarin

  Yavuz, Sevtap Çaglar

  Cynarin (1,3-o-dicaffeoylquinic acid) is one of the biologically active functional food components which is the most well-known caffeoylquinic acid derivative found in artichoke. The structural and electronic features of cynarin compound were investigated theoretically using density functional theory (DFT). The highest occupied molecular orbital (HOMO) and the least occupied molecular orbital (LUMO) are the most significant orbitals in molecules, these orbitals are quite helpful to know several molecular features such as the chemical reactivity, kinetic stability, electronegativity, chemical potential, electrophilicity index, chemical hardness and softness and electronegativity. Molecular orbital analysis HOMO-LUMO was used to explore the stability of the molecule. Moreover, physicochemical properties, drug-likeness, and toxicity estimation of the cynarin compound were appraised owing to ADMET (including absorption, distribution, metabolism, excretion, and toxicology). Molecular docking was carried out to examine the biological activity of the cynarin compound. 5A19, a liver cancer biomarker, is human methionine adenosyl-transferase enzymes. Cynarin-methionine adenosyl-transferase enzyme binding energy value was calculated as -7.9 kcal/mol. As a result, this in silico study confirmed that cynarin has the potential to be a drug by revealing its protective effect against liver diseases.

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• ArticleYayıncıda açık erişim2024/r/ebyu/12736
  IN VITRO AND IN SILICO STUDIES ON LIGNAN SECOISOLARICIRESINOL DIGLUCOSIDE; [LİGNAN SEKOİZOLARİSİRESİNOL DİGLUKOSİT ÜZERİNE İN VİTRO VE İN SİLİKO ÇALIŞMALAR]

  Bayar, İrem; Çağlar Yavuz, Sevtap; Akkoç, Senem

  Objective: Lignans are important biologically active compounds in diphenolic structure. Secoisolariciresinol diglucoside (SDG) is a significant type of lignan known to have anti-cancer properties. This study aimed to investigate the antiproliferative activity properties of SDG on hepatocellular carcinoma cells (HepG2), colorectal cancer cells (DLD-1), lung carcinoma (A549), and prostate cancer (PC3) cell lines. Material and Method: Cell viability of cancer cells was determined by the MTT method after treatment with various concentrations of SDG at 48 or 72 hours. The DFT (Density Functional Theory) analysis of the SDG was performed using Spartan'10 and visualized. Drug-likeness and absorption, distribution, metabolism, excretion, and toxicity (ADME-Tox) properties of this compound were examined. Molecular docking was carried out to research the biological activity of SDG. Result and Discussion: Our results showed that SDG exhibited significant cytotoxicity only against DLD-1 cells with IC50 value of 37.45 µM, but inactive against other cancer cell lines as in vitro. 4UYA, which biomarker for colon cancer, is the crystal structure of the MLK4 kinase domain. The binding energy value for the SDG-MLK4 kinase domain was calculated as -6.1 kcal/mol. Anticancer potential was verified by in vitro assay and in silico molecular docking study. In conclusion, this study revealed the protective aspect of SDG against colon cancer and showed that it has promising anticancer activity.

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• ArticleYalnız künye2024/r/ebyu/12301
  Experimental and numerical investigation of the stenosed coronary artery taken from the clinical setting and modeled in terms of hemodynamics

  Sonmez, Fatin; Karagoz, Sendogan; Yildirim, Orhan; Firat, Ilker

  The study was carried out to investigate the effect of the artery with different pulse values and stenosis rates on the pressure drop, the peristaltic pump outlet pressure, fractional flow reserve (FFR) and most importantly the amount of power consumed by the peristaltic pump. For this purpose, images taken from the clinical environment were produced as models (10 mm inlet diameter) with 0% and 70% percent areal stenosis rates (PSR) on a three-dimensional (3D) printer. In the experimental system, pure water was used as the fluid at 54, 84, 114, 132, and 168 bpm pulse values. In addition, computational fluid dynamics (CFD) analyzes of the test region were performed using experimental boundary conditions with the help of ANSYS-Fluent software. The findings showed that as PSR increases in the arteries, the pressure drop in the stenosis region increases and this amount increases dramatically with increasing effort. An increase of approximately 40% was observed in the pump outlet pressure value from 54 bpm to 168 bpm in the PSR 0% model and 51% increase in the PSR 70% model. It has been observed that the pump does more work to overcome the increased pressure difference due to increased pulse rate and PSR. With the effect of contraction, the power consumption of the pump increased from 9.2% for 54 bpm to 13.8% for 168 bpm. In both models, the Wall Shear Stress (WSS) increased significantly. WSS increased abruptly in the stenosis and arcuate regions, while sudden decreases were observed in the flow separation region.

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