Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 6Citation - Scopus: 6A Novel 2-Aminophenalenone Fluorescent Probe Designed for Monitoring H2o2 for in Vitro and in Vivo Bioimaging(Elsevier, 2024) Saygılı, Ecem; Ersöz Gülseven, Esra; Kıbrıs, Erman; Çakan Akdoğan, Gülçin; Üçüncü, MuhammedA significant compound in living organisms, hydrogen peroxide (H2O2) plays a dual role as a signalling molecule in cellular communication and as a pivotal biomarker in assessing disease and oxidative stress. Thus, the detection of abnormal changes in H2O2 levels is essential to understanding its function and involvement in biological systems. The growing demand to meet the specific needs for applications, particularly in biological systems, has sharpened focus on highly sensitive, highly selective molecular sensors and, in turn, heightened interest in these diagnostic tools with innovative designs. In our study, 2-aminophenalenone (2-AP) was used for the first time as a fluorophore in a fluorescent probe. The 2-APB molecule obtained from the reaction of 2-AP with 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzyl chloroformate exhibited a highly selective and sensitive (i.e. 62 nM) detection profile for H2O2 compared with the other reactive oxygen species, anions, and metal cations. Moreover, offering naked-eye detection in aqueous solutions, 2-APB demonstrated excellent sensing performance, detection and real-time monitoring in relation to exogenous H2O2 in cells and endogenous H2O2 in zebrafish embryos. © 2024 Elsevier B.V.Article Citation - WoS: 44Citation - Scopus: 45Carbon Nanotube-Graphene Supported Bimetallic Electrocatalyst for Direct Borohydride Hydrogen Peroxide Fuel Cells(Elsevier Ltd., 2021) Uzundurukan, Arife; Akça, Elif Seda; Budak, Yağmur; Devrim, YılserAt present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm2 active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm2, 125 mW/cm2 and 113 mW/cm2 were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 °C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. © 2020 Elsevier LtdArticle Citation - WoS: 86Citation - Scopus: 98Characterization and Catalytic Activity of Cufezsm-5 Catalysts for Oxidative Degradation of Rhodamine 6g in Aqueous Solutions(Elsevier Ltd., 2010) Dükkancı, Meral; Gündüz, Gönül; Yılmaz, Selahattin; Yaman, Y. C.; Prikhod’ko, R. V.; Stolyarova, I. V.This study presents an evaluation of the catalytic performances of Fe and Cu containing ZSM-5 zeolites for oxidation of Rhodamine 6G. Fe and Cu were loaded by ion exchange or through hydrothermal synthesis. The catalytic process was carried out in an aqueous solution using H2O2 as an oxidant. The catalyst prepared by hydrothermal synthesis showed the highest activity (100% decolorization, 59.1% aromatic degradation and 51.8% TOC removal at initial pH of 3.5). This catalyst was stable against leaching even at low pH. The change in activity of the catalysts prepared was attributed to incorporation of the Fe and Cu species with ZSM-5. Fe and Cu were in structural locations - in the framework - in the catalyst prepared by hydrothermal synthesis while there were extraframework cations or species in catalysts prepared by ion exchange. Incoporation of Cu into FeZSM-5 increased its catalytic activity. © 2010 Elsevier B.V. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 12Effects of Hot Rehydration in the Presence of Hydrogen Peroxide on Microbial Quality, Texture, Color, and Antioxidant Activity of Cold-Stored Intermediate-Moisture Sun-Dried Figs(John Wiley and Sons Inc., 2005) Demirbüker Kavak, Dilek; Arcan, İskender; Tokatlı, Figen; Yemecioğlu, AhmetPectin methylesterase (PME) causes considerable softening in intermediate-moisture (IM) figs rehydrated at 30°C and cold stored at 28% to 29% moisture content. Rehydration of figs at 80°C for 16 min inactivated PME partially (25-30%), but this did not prevent the softening over 3 mo of cold storage. Also, heating did not reduce the microbial load of figs significantly and increased their browning. In contrast, rehydration of figs 1st in 2.5% H2O2 at 80°C for 8 min and then in water at 80°C for 8 min reduced the microbial load of IM figs significantly, turned their brown color to yellow-light brown, and maintained their desired textural properties. The residual H2O2 in IM figs decomposed in 3 or 1.5 wk by the in situ catalase or by application of the iron (II) sulfate-ascorbic acid residue elimination method, respectively. Hot rehydration did not affect the antioxidant activity of IM figs, but treatment of figs with H2O2 increased their antioxidant activity slightly. These results indicate that the hot rehydration of figs in the presence of H 2O2 and cold storage may be applied to obtain safe and SO2-free light-colored IM fig products.Article Citation - WoS: 38Citation - Scopus: 43Degradation Kinetics of Anthocyanins From Sour Cherry, Pomegranate, and Strawberry Juices by Hydrogen Peroxide(John Wiley and Sons Inc., 2002) Özkan, Mehmet; Yemenicioğlu, Ahmet; Asefi, N.; Cemeroglu, BekirDegradations were studied at different hydrogen peroxide (H2O2] concentrations (9.31 to 27.92 mmol. L-1] over a range of 10 ° to 30 °C. Degradation of anthocyanins by H2O2 was described by first-order function. Comparison of t1/2 values revealed that sour cherry anthocyanins were the most resistant to H2O2, followed by pomegranate and strawberry anthocyanins. Thus, the removal of residual H2O2 from the juice contact surfaces of aseptically packaged strawberry juices should be controlled more carefully to prevent anthocyanin degradation. Respective Ea values were between 9.4 to 11.1, 9.5 to 11.4, and 11.4 to 12.2 kcal.mol-1; and Q10 values between 1.59 to 2.22, 1.62 to 2.05, and 1.76 to 2.36 for strawberry, sour cherry, and pomegranate anthocyanins.Article Citation - WoS: 8Citation - Scopus: 9Effect of Hydrogen Peroxide on Sour Cherry Anthocyanins(Hindawi Publishing Corporation, 2000) Özkan, Mehmet; Yemenicioğlu, Ahmet; Çıtak, Bahar; Cemeroğlu, BekirDegradation of sour cherry anthocyanins was studied at different H2O2 concentrations (0.233-11.63 mmol.L-1) over the temperature range of 20-55C. Degradation reaction fitted to a first order kinetic model progressed very rapidly even at low H2O2 concentrations. Thus, the t1/2 values at 20C varied between 111-20 h in the concentration range of 0.233-2.327 mmol.L-1 H2O2. The degradation of anthocyanins occurred at a faster rate with increasing temperature at 5.82 and 11.63 mmol.L-1 H2O2 concentrations. Between 25-55C, activation energies (Ea) were 9.53 and 10.60 kcal.mol-1 for 5.82 and 11.63 mmol.L-1 H2O2 concentrations, respectively. Higher Ea value at 11.63 mmol.L-1 H2O2 concentration indicated that the effect of temperature increased at higher H2O2 concentrations. A quadratic relationship (y = -0.0031x2 + 0.0218x + 0.0008, R2 = 0.996) was found between the degradation rates at 20C and H2O2 concentrations of 0.233-2.327 mmol.L-1. According to this equation, k of 1.12 × 10-3 h-1 and t1/2 of 26 days at 20C may be expected at 0.5 ppm (0.0147 mmol.L-1) H2O2 concentration, i.e., the max. allowable H2O2 level by FDA in the finished food packages.