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Öğe Bovine carbonic anhydrase (bCA) inhibitors: Synthesis, molecular docking and theoretical studies of bisoxadiazole-substituted sulfonamide derivatives(Elsevier, 2024) Eybek, Abdulbaki; Kaya, Mustafa Oguzhan; Gulec, Ozcan; Demirci, Tuna; Musatat, Ahmad Badreddin; Ozdemir, Oguzhan; Oner, Mine Nazan KerimakThis paper describes the in vitro inhibition potential of bisoxadiazole-substituted sulfonamide derivatives (6a-t) against bovine carbonic anhydrase (bCA) after they were designed through computational analyses and evaluated the predicted interaction via molecular docking. First, in silico ADMET predictions and physicochemical property analysis of the compounds provided insights into solubility and permeability, then density functional theory (DFT) calculations were performed to analyse their ionization energies, nucleophilicity, in vitro electron affinity, dipole moments and molecular interactions under vacuum and dimethyl sulfoxide (DMSO) conditions. After calculating the theoretical inhibition constants, IC50 values determined from enzymatic inhibition were found between 12.93 and 45.77 mu M. Molecular docking evaluation revealed favorable hydrogen bonding and pi-interactions of the compounds within the bCA active site. The experimentally most active compound, 6p, exhibited the strongest inhibitory activity with a theoretical inhibition constant value of 9.41 nM and H-bonds with Gln91, Thr198, and Trp4 residues and His63 Pi-cation interactions with His63 residues. Overall, the study reveals promising bCA blocking potential for the synthesized derivatives, similar to acetazolamide.Öğe CdSeTe Kuantum Noktaları ile Bromo Krezol Mor Kombinasyonunun Spektrofotometrik Değerlendirmesi(2023) Demirci, Tuna; Elibol, ErdemKuantum noktalar (QDs) sahip oldukları benzersiz optik ve elektronik özellikleri ile son yıllarda birçok farklı teknolojik alanda popüler hale gelmişlerdir. Bu durum QD'lar ile organik bileşiklerin etkileşimine olan ilgiyi arttırmaktadır. Bu çalışmada bu ilgiye temel alarak, CdSeTe QD'lar ile Brom Krezol Moru (BCP) kloroform içerisinde oda sıcaklığın da etkileşimini ve CdSeTe QDs/BCP yapısının spektroskopik olarak karakterizasyonu açıklamayı amaçlamıştır. Bu amaç doğrultusunda CdSeTe QDs/ BCP oluşumunun etkileşimleri spektroskopik olarak Fourier dönüşümlü kızılötesi spektroskopisi (FTIR), absorbans ve emisyon üzerinden karakterizasyon çalışmaları yapılmıştır. BCP'nin CdSeTe QD'lar ile hibritleşmesiyle QDs'nin lüminesans pikinde 19 kat azalma tespit edilmiştir. Bununla birlikte Brom Krezol Moru (BCP) ile hibritleşen CdSeTe QD'lar BCP'nin soğurma özelliğini 112.8 katına kadar arttırmıştır.Öğe Comprehensive experimental and computational analysis of endemic Allium tuncelianum: Phytochemical profiling, antimicrobial activity, and In silico studies for potential therapeutic applications(Elsevier Ltd, 2025) Ozdemir, Oguzhan; Yilmaz, Nurten; Musatat, Ahmad Badreddin; Demirci, Tuna; Çete, Servet; Yerlikaya, Emrah; Kaya, Mustafa OğuzhanAllium tuncelianum (TG), an endemic garlic species from Tunceli, Turkey, was investigated using a multidisciplinary approach combining experimental and computational methods. Density Functional Theory (DFT) calculations with B3LYP/def2-SVP/def2-TZVP basis sets were employed to analyze electronic properties, reactivity, and stability under gas and ethanol conditions. Headspace/GC-MS identified 10 major components, with diallyl disulfide (48.03 %) and 1-propene (20.72 %) as predominant. Antimicrobial assays revealed potent activity against MRSA, Salmonella paratyphi A, and E. coli, with MIC values as low as 0.063 mg/mL. Antioxidant capacity, evaluated via DPPH, metal chelating, and FRAP assays, showed promising results, with the water extract exhibiting the highest activity (1.74 mg BHT equivalent/mL). DFT and molecular docking studies highlighted key compounds as potential inhibitors of E. coli Gyrase B, with binding energies of −5.68 and −6.07 kcal/mol. ADME predictions indicated favorable drug-like properties, though some compounds showed potential CYP450 interactions and toxicity. This study provides a comprehensive understanding of TG's biochemical profile and therapeutic potential, offering insights for future research and optimization. © 2025 Elsevier B.V., All rights reserved.Öğe Density Functional Theory, Molecular-Docking Studies and Inhibition Effects of Pharmaceutical Active Ingredients on Xanthine Oxidase(Springer, 2025) Kaya, Mustafa Oguzhan; Dandan, Enes; Demirci, Tuna; Ozdemir, Oguzhan; Kaya, Yesim; Arslan, MustafaXanthine oxidase (XO) is a crucial part of human metabolism because of its activity on purine metabolism. In this study, drospirenone, dutasteride, ketoprofen, miconazole, mirabegron, mycophenolate mofetil, nimesulide, phenylephrine hydrochloride, prasugrel hydrochloride, ranolazine, tropicamide, and melatonin were used as drug active ingredients and the inhibitory effect of 12 drug active ingredients on XO was evaluated in vitro at the concentration of each compound required to inhibit it by 50% (IC50). As a result of the study, dutasteride exhibited the lowest highest occupied molecular orbital-lowest unoccupied molecular orbital (triangle E = 2.522 eV) energy gap, the best isotropic polarizability (331.020 atomic units), the best docking score (-11.30 kcal/mol), and the best inhibition value (IC50 = 65.80 mu M).Öğe The Effect of Cryogenic Treatment on Some Chemical, Physical, and Mechanical Properties of Thermowood (R) Oriental Spruce(North Carolina State Univ Dept Wood & Paper Sci, 2022) Aytin, Ayhan; Uygur, İlyas; Demirci, Tuna; Akgül, İrfanEffects of cryogenic treatment on the chemical, physical, and mechanical properties of oriental spruce wood, which was heat-treated with the Thermowood (R) method, were investigated in this work. Cryogenic treatment, which is a secondary process applied to industrially heat-treated ferrous and non-ferrous metallic materials, was applied to Thermowood (R) Oriental spruce wood. For this purpose, Oriental spruce wood was first heat-treated at two different temperatures (190 and 212 degrees C), and then both Thermowood (R) and control samples were cryogenically treated at -80 degrees C. The effects on shrinkage and swelling pressure resistance parallel to fibers, and the elemental structure were examined. The findings revealed that the improvement in shrinkage and swelling continued with heat treatment, and there was an average increase of 18 and 14.5%, respectively, in the compressive strength parallel to fibers compared with control and heat-treated samples. The FT-IR analysis showed that the wood compound structure was mostly cellulosic. The difference between the carbon-oxygen ratio in the cryogenically-treated wood decreased compared to the percentage change in the three basic elements, and the amount of hydrogen increased proportionally.Öğe Exergetic, exergoeconomic, and sustainability analyses of diesel-biodiesel fuel blends including synthesized graphene oxide nanoparticles(Elsevier Sci Ltd, 2022) Uysal, Cüneyt; Ağbulut, Ümit; Elibol, Erdem; Demirci, Tuna; Karagöz, Mustafa; Sarıdemir, SuatIn this study, graphene oxide nanoparticles were synthesized and added to 85 vol% diesel + 15 vol% biodiesel (D85B15) blend with amounts of 100 ppm, 500 ppm, and 1000 ppm to prepare D85B15GO100, D85B15GO500, and D85B15GO1000 blends, respectively. The prepared fuels were tested in a compression ignition diesel engine. The experiments were performed on various engine loads ranging from 3 Nm to 12 Nm with intervals of 3 Nm at fixed crankshaft speed of 2400 rpm. The results obtained from the experiments were used in the exergetic, exergoeconomic, and sustainability analyses of test engine. According to the results, D85B15GO100 had the highest exergy efficiency and sustainability index and the second-cheapest specific exergy cost of crankshaft work. As a result, at 12 Nm, the exergy efficiency, specific exergy cost of work produced by crankshaft, and sustainability index values of test engine were 25.82%, 75.82 $/GJ, 1.348 for D85B15, whereas these values were 27.05%, 77.52 $/GJ, 1.371 for D85B15GO100, respectively. Increase in graphene oxide nanoparticle content in the blend led to decrease in the exergy efficiency and sustainability index and increase in the specific exergy cost of crankshaft work. Finally, it can be concluded that D85B15GO100 is optimal fuel compared to the fuels tested in this study.Öğe Exploring the Influence of Various Solvents on the Structural, Optical, and Spectroscopic Properties of MgO(Tayfun UYGUNOĞLU, 2024) Kareem, Rebaz Obaıd; Ahmad, Bast; Bulut, Niyazi; Demirci, Tuna; Ercan, Ismail; Ercan, Filiz; Ateş, TankutMagnesium oxide (MgO) samples were manufactured at different temperatures using various solvents of water and ethanol. MgO structure was also modeled and its vibration modes were calculated. The kind of solvent as-used in the synthesis and calcination temperature caused changes in the lattice parameter, crystallinity, and crystallite size. The crystallite size increased with increasing production temperature for both series of the MgO. The morphology and bandgap energy were also affected significantly by the solvent and calcination temperature.Öğe Fluorescent CdTe/ZnS Core/Shell Quantum Dots for Sensitive Metabolite Detection in Real Samples(Springer/Plenum Publishers, 2025) Agbulut, Melahat Sevgul Bakay; Elibol, Erdem; Cadirci, Musa; Demirci, TunaThis study highlights the aqueous synthesis of CdTe/ZnS core/shell quantum dots (QDs) and their application as fluorescence sensors for detecting critical metabolites, including folic acid, glucose, and vitamin C, in real biological samples. The synthesized QDs exhibit excellent quantum efficiency, stability, and biocompatibility, enhanced by mercaptopropionic acid (MPA) ligands, enabling eco-friendly and accurate sensing. Detection limits of 0.84 mu g/mL for folic acid, 0.33 mM for glucose, and 1.15 mu g/mL for vitamin C were achieved with high linearity (R-2 > 0.97). These results underscore the potential of CdTe/ZnS QDs in advanced biosensing technologies, offering sensitive and selective metabolite detection through a robust FRET-based mechanism. The versatility and aqueous solubility of these QDs pave the way for their integration into multiplex diagnostic systems for enhanced biomedical applications.Öğe High efficiency green and red emitting CdSeTe quantum dots: Synthesis and PLQY improvement for optical applications(Elsevier Science Sa, 2025) Elibol, Erdem; Demirci, Tuna; Koc, DurukanObtaining stable QDs with different emission colors and high PLQY values for optoelectronic applications is important. There are currently applied treatment methods to increase the PLQY value and stabilization of QDs. On the other hand, variations in the surface-to-volume ratio associated with changes in QD size indicate that the treatment methods applied must be optimized according to the specific size of the QDs. This study focuses on the optimization of the synthesis and treatment processes of green and red emission CdSeTe QDs with high PLQY for use in optoelectronic devices. Initially, the synthesis processes for green and red emission QDs were optimized according to precursor molar amounts, synthesis time and synthesis temperature. Then, chloride treatment, CdS and ZnS shell coating methods were optimized and applied separately to increase the PLQY values of these QDs. The results showed that the PLQY value increased up to 95.23 % with 30 % CdCl2 treatment by mass for green emitting CdSeTe QDs and up to 96.31 % with 40 % CdCl2 chloride treatment by mass for red emitting QDs. The study includes a comprehensive comparison of emission, absorption, XRD, elemental analysis, CV, PL lifetime, HR-TEM analysis and stabilization analysis for the synthesized CdSeTe QD types.Öğe In silico investigation of tetrazole and oxadiazole compounds as inhibitors of the dengue virus NS5 protein: Synthesis, DFT, ADME and molecular docking analysis(Elsevier Ireland Ltd, 2025) Demirci, Tuna; Musatat, Ahmad Badreddin; Kaya, Mustafa Oguzhan; Arslan, MustafaThis study investigates the therapeutic potential of novel tetrazole and oxadiazole derivatives targeting the Dengue virus NS5 protein through an integrated computational and experimental approach. A series of nitrilesubstituted 1,4-dihydropyridine (1,4DHPs) derivatives were synthesized and converted into tetrazole and 1,3,4-oxadiazole analogs using established protocols. Structural characterization was performed via NMR, FT-IR, and elemental analysis. Molecular docking studies against the NS5 protein (PDB ID: 6KR2) revealed superior binding affinities for several compounds (Delta G = -7.18 to -9.58 kcal/mol), with compound 5 exhibiting the strongest interaction (Delta G = -9.58 kcal/mol, theoretical IC50 = 94.64 nM), outperforming the reference ligand SAH (Delta G = -7.18 kcal/mol). ADME profiling demonstrated favorable drug-likeness, acceptable solubility, bloodbrain barrier penetration, and CYP450 metabolic stability. DFT analyses elucidated electronic properties, including HOMO-LUMO gaps (2.72-4.80 eV) and electrophilicity indices (13.5-23.6 eV), correlating with observed bioactivity. Toxicity predictions identified compound-specific liabilities requiring optimization. These findings highlight the promise of tetrazole-oxadiazole hybrids as potent NS5 inhibitors, warranting further preclinical validation for Dengue therapeutic development.Öğe Innovative CuLaSe2 and ZnCuLaSe2 quantum dots: advancing quantum dot sensitized solar cell applications(Springer Heidelberg, 2025) Demirci, TunaThe utilisation of quantum dots (QDs) as promising materials for next-generation photovoltaics is a recent development. The optical properties of QDs can undergo tuning, and they enhance energy conversion efficiencies. In this study, CuLaSe2 and Zn-doped CuLaSe2 (ZnCuLaSe2) QDs, specifically tailored for quantum dot-sensitized solar cells (QDSSCs). These QDs, which are environmentally friendly as they are free of toxic Cd and Pb elements, exhibit adjustable energy band gaps and improved photoluminescence quantum yields. The incorporation of Zn into CuLaSe2 QDs led to a significant blue shift in optical properties and enhanced photovoltaic performance. The highest power conversion efficiency (PCE) achieved was 2.52% for ZnCuLaSe2 QDs, compared to 1.94% for CuLaSe2 QDs. This improvement is attributed to Zn doping, which enhances charge separation, suppresses surface trap states, and facilitates better electron transfer by modifying the energy band alignment. The synthesis methods have been developed in such a way that they are scalable, and are also compatible with low-cost, eco-friendly production processes; this underscores their feasibility for industrial applications. It can be concluded that the present study fulfills a vital function within the global energy research landscape by identifying two QDs that have the potential to be key components in advancing photovoltaic technology.Öğe Interaction and Characterization of The Triarylmethane Dye Bromophenol Blue with CdSeTe Quantum Dots(2021) Elibol, Erdem; Demirci, TunaThe use of hybrid associates in biological, optoelectronics and energy fields are increasing dayby day. In this context, in this study, CdSeTe Quantum dots (QD): Bromophenol Blue (BPB)hybrid associates were studied for the first time in the literature and their spectroscopiccharacterizations were examined. In the study, CdSeTe QDs were synthesized withtrioctylphosphine (TOP) ligands by hot injection method, and it was planned that the BPBwould passivate the surface of the QD by interacting with the TOP ligand of the CdSeTe QDs.CdSeTe QD: BPB hybrid associates were prepared in different concentrations, and the effectsof QD: BPB ratios on absorbance and emission characterizations were examined. Structureshave been characterized using Uv-vis, PL, ICP-OES and FTIR. With the results found, thepredictive mechanism has been put forward.Öğe Investigating the effect of Zn doping and temperature on the photoluminescence behaviour of CuLaSe2 quantum dots(Wiley, 2024) Cadirci, Musa; Elibol, Erdem; Demirci, Tuna; Kurban, MustafaIn this study, CuLaSe2 and ZnCuLaSe2 quantum dots (QDs) with a mean size of similar to 4 nm were synthesized and characterized, and their temperature-dependent photoluminescence (PL) properties were studied in the temperature range from 90 to 300 K for the first time. The results show that the obtained QDs were spherical and revealed excitonic band gaps. The PL intensity for both types of materials decreased when increasing the temperature to 300 K, which was attributed to the nonradiative relaxation and thermal escape mechanisms. As the temperature was increased, the PL linewidths broadened, and PL peak energies were red shifted for both types of QDs due to the exciton-phonon coupling and lattice deformation potential mechanisms. In addition, we found that as the temperature was decreased, the PL spectrum of ZnCuLaSe2 QDs contained two extra components, which could be attributed to the shallow defect sites (low energy peak) and the crystal phase transition process (high energy peak). The spectrum of CuLaSe2 QDs contained one extra component, which could be attributed to the crystal phase transition process.Öğe Investigation on structural, optical, thermal, and dielectric properties of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum nanocomposite prepared by pulsed laser ablation(Elsevier, 2024) Haladu, Shamsuddeen A.; Elsayed, Khaled A.; Ercan, Ismail; Ercan, Filiz; Kayed, T. S.; Demirci, Tuna; Yildiz, MesutPolymer nanocomposite films of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum (CP/ SMAC/Mo) were fabricated by pulsed laser ablation of Mo in the polymer solution for 10, 20, and 30 min. The films were then characterized by various analytical methods. X-ray diffraction (XRD) revealed that the addition of Mo to CP/SMAC removed the crystalline peaks of Mo without changing the amorphous nature of the copolymer. According to the scanning electron microscopy (SEM) and atomic force microscopy (AFM) patterns, Mo atoms were trapped in the amorphous polymer stacks. The energy -dispersive X-ray (EDX) spectrum features C, O, and Mo. FTIR confirmed the embedding of Mo in the polymers. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out on the samples. The pristine polymer film exhibited a band gap energy of 2.9 eV, which decreased to 2.05 eV because of the loading of the Mo nanoparticles. The intensity of the photoluminescence (PL) peak of the films increases with ablation time such that the absorption intensity of the film at a lambda max of 426 nm increases by trifold during the 30 min of irradiation, which is consequently due to the increased amount of Mo in the nanostructure. The incorporation of Mo in the polymer matrix enhances the dielectric constant ( epsilon') (6.28 -18.13) and ac conductivity ( sigma ac ) (3.19 x 10 - 5 -1.12 x 10 -4 S/cm) of the polymer with negligible dielectric loss. The results suggest possible technological utilization of these materials in such applications as supercapacitors, light -emitting diodes, and organic optoelectronic devices, among others.Öğe Magnetic Behavior and Nutrient Content Analyses of Barley (Hordeum vulgare L.) Tissues upon CoNd0.2Fe1.8O4 Magnetic Nanoparticle Treatment(Springer International Publishing Ag, 2020) Tombuloglu, Huseyin; Slimani, Yassine; Alshammari, Thamer; Tombuloglu, Guzin; Almessiere, Munirah; Baykal, Abdulhadi; Demirci, TunaThis study investigates (i) in planta uptake and transfer of magnetic nanoparticles (MNPs) in the plant body and (ii) impact of MNPs on plant nutrition. For these purposes, barley (Hordeum vulgare L.) seedlings were subjected by varied MNP doses (125 to 1000 mg L-1 of CoNd0.2Fe1.8O4) for 3 weeks in a hydroponic system. Plant tissues (root and leaf) were analyzed by using vibrating sample magnetometer (VSM) and inductively coupled plasma optical emission spectrometer (ICP-OES) techniques to understand MNPs' uptake and translocation in the plant body, and plant nutrition status as well. Elemental composition and magnetic behavior analyses of plant parts proved that MNPs, sized in 8.4 +/- 0.05 nm, are uptaken by the plant roots and led to an increase in iron (Fe), neodymium (Nd), and cobalt (Co) contents of leaves (p < 0.005). However, compared with the untreated control, the amount of some macro- and micro-elements (K, Ca, Mg, Mn, and P) are declined in the leaf by increased MNP doses (p < 0.05). Root-to-leaf translocation index (%) of the elements were dramatically decreased, except the one for Fe which increased from 25 (control) to 55% in 1000 mg L-1 condition. Accordingly, MNPs are uptaken by the plant roots and transferred to the leaves. However, it suppresses the translocation of essential nutrients. This finding shows that MNPs used in this study is detrimental for plant mineral nutrition. Besides, the VSM technique coupled with ICP-OES enables to track MNPs in the plant body.Öğe Mineral oils modified with CdSeTe QDs for improved stability and dielectric performance in high-voltage applications(Springer, 2025) Bicen, Yunus; Elibol, Erdem; Demirci, TunaThis study explored the application of CdSeTe quantum dots (QDs) in mineral oils for high-voltage applications through a comprehensive approach. CdSeTe QDs were synthesized using an organometallic method and added to mineral oil at concentrations of 1 mg/L (C1), 5 mg/L (C2), and 10 mg/L (C3). The samples' stability condition was monitored for a long period, and physicochemical tests were performed. Experimental results show that QD-modified oils have enhanced electrical properties compared to the base oil. The breakdown voltage was in the range of 17 to 23 kV for the base oil, while the breakdown voltage was in the range of 20 to 39 kV for the QD-modified (C2) insulating fluid sample. Throughout the 25-day monitoring period, the QDs were found to be properly dispersed in oil and free of aggregation in all samples. Values such as density and viscosity remained fairly constant due to the relatively low concentration ratio. However, an increase in total acid number was observed with increasing concentration. These results imply that QD-enhanced insulation oils may have applications in high-voltage applications in the future. The main innovation of this study lies in demonstrating that CdSeTe QDs can significantly enhance the dielectric strength of mineral oils while maintaining their essential physicochemical properties, offering a novel approach for improving insulation performance in high-voltage applications.Öğe One-pot synthesis of Hantzsch dihydropyridines using a highly efficient and stable PdRuNi@GO catalyst(Royal Soc Chemistry, 2016) Demirci, Tuna; Çelik, Betül; Yıldız, Yunus; Eriş, Sinan; Arslan, Mustafa; Şen, Fatih; Kılbaş, BenanAddressed herein, highly monodispersed PdRuNi nanoparticles furnished with graphene oxide (PdRuNi@GO NPs) were prepared as novel, stable, efficient and exceptionally reusable heterogeneous catalysts for 1,4-dihydropyridine synthesis via multicomponent condensation reactions of various aldehydes with dimedone, ammonium acetate and ethyl acetoacetate at 70 degrees C in DMF with efficient catalytic performance. These synthesized novel materials were characterized by transmission electron microscopy (TEM), high resolution electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). This presented one pot catalytic process is described as a new methodology of the Hantzsch synthesis, which can be assessed as quite simple and efficient as well as exceptionally reusable. At the end of the reaction, one of the highest yields and the shortest times were obtained for the model reaction in the presence of novel monodisperse PdRuNi@GO NPs.Öğe Rabbit muscle pyruvate kinase activators: Synthesis, molecular docking and theoretical studies of N-substituted sulfonamide derivatives(Elsevier, 2024) Kaya, Mustafa Oguzhan; Demirci, Tuna; Musatat, Ahmad Badreddin; Ozdemir, Oguzhan; Sonmez, Fatih; Kaya, Yesim; Arslan, MustafaPyruvate kinase (PK) activators have potential therapeutic applications in diseases such as sickle cell anemia. In this study, N-Substituted sulfonamide derivatives of 1,4-dihydropyridines were synthesized and evaluated as PK activators in vitro and using molecular docking studies. The compounds were synthesized by reacting dicarbonyl compounds with ammonium acetate, 5-nitrobenzaldehyde, and alumina sulfuric acid (ASA), followed by reduction and sulfonylation. The structures of the compounds were analyzed using spectroscopic techniques. DFT calculations provided insights into the electronic properties. Molecular docking of the compounds into the active site of PK showed favorable binding interactions. ADME evaluation indicated suitable solubility, BBB permeation, and lack of CYP450 inhibition. Overall, this study demonstrates the potential of new hybrid 1,4-dihydropyridine substituted sulfonamides as PK activators for further development. According to AC50 values, the compound (DTS-F-7, 0.97 mu M) is about 100-fold higher affective than the clinically used sulfonamide compound (AC50 = 90 mu M) for PK.Öğe Rational Design, Synthesis, and Computational Investigation of Dihydropyridine [2,3-d] Pyrimidines as Polyphenol Oxidase Inhibitors with Improved Potency(Springer, 2024) Kaya, Mustafa Oguzhan; Kerimak-Oner, Mine Nazan; Demirci, Tuna; Musatat, Ahmad Badreddin; Ozdemir, Oguzhan; Kaya, Yesim; Arslan, MustafaPolyphenol oxidase (PPO) is an industrially important enzyme associated with browning reactions. In the present study, a set of ten new dihydropyridine [2,3-d] pyrimidines (TD-Hid-1-10) were synthesized and was found to be proven characteristically by 1H NMR, 13C NMR, IR, elemental analysis, and assessed as possible PPO inhibitors. PPO was purified from banana using three-phase partitioning, achieving an 18.65-fold purification and 136.47% activity recovery. Enzyme kinetics revealed that the compounds TD-Hid-6 and TD-Hid-7 are to be the most potent inhibitors, exhibiting mixed-type inhibition profile with IC50 values of 1.14 mu M, 5.29 mu M respectively against purified PPO enzyme. Electronic structure calculations at the B3LYP/PBE0 level of theories using def-2 SVP, def2-TZVP basis sets with various molecular descriptors characterized the electronic behavior of studied derivatives TD-Hid-1-10. Molecular electrostatic potential (MEP) and reduced density gradient analyses of RDG-NCI provided insights into charge distributions and weak intermolecular interactions. Docking study simulations predicted binding poses within crucial amino acid sequence in the 2y9x enzyme's active site, which is typically similar in sequence to the PPO form is not allowed. Ligands were analysed in terms of binding energies, inhibitor concentrations (mM) and various molecular interactions such as H-bonds, H-carbon, pi-carbon, pi-sigma, pi-sigma, pi-pi T-shaped, pi-pi stacked, pi-alkyl, Van der Waals and Cu interactions. The lowest binding energy (-7.83 kcal/mol) and the highest inhibitory effect (1.83 mM) were shown by the ligand Td-Hid-6, which forms H-bonds with Met280 and Asn260, exhibits pi-sigma interactions with His61 and pi-alkyl interactions with Val283. Other ligands also showed different interactions with various amino acids; for example, the Td-Hid-1 ligand formed H-bonds with His244 and showed pi-sigma interactions with His244 and Val283.Öğe Structural, optical, and electrical investigation of multilayered MnO2(n)/ NiO(p) heterojunctions for supercapacitors applications(Elsevier, 2023) Alanazi, Maha; Ghrib, Taher; Ercan, Filiz; Alsubaie, Mizna; Demirci, Tuna; Kaygili, Omer; Kayed, Tarek S.Heterojunctions of alternating MnO2 and NiO thin films were deposited on an Indium Tin Oxide (ITO). The MnO2 and NiO thin films were synthesized by electrodeposition and sol-gel methods respectively. The structural morphology of the synthesized heterojunctions was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The microstructural and chemical compositions were examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman techniques. The optical properties were investigated by Ultraviolet-Visible (UV) analysis. The electrical conductivity, specific capacitance, and charge carrier density were determined using the Hall effect and Electrochemical impedance spectroscopy (EIS) methods. As a result, it was found that the MnO2 and NiO thin films crystallize in tetragonal and cubic crystal systems respectively. Increasing the number of NiO/MnO2 heterojunctions increases the electrical conductivity from 9.7 x 10- 7 to 1.2 x 10-3 S.cm- 1, the bandgap decreased 3.16 to 2.62 eV, the volume carrier density rises from 5.17 x 1011 to 4.62 x 1012 cm-3. The specimens constituted of two and four alternative staked MnO2 and NiO layers are characterized by a specific capacitance of 3.6 x 103 and 5.8 x 103 F.g -1 and capacitance retention of 14.8 and 12.9% which consider them promising materials for supercapacitor devices.
