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: 1Citation - Scopus: 1Enhanced Properties of Tio<sub>2</Sub> Nanotubes Through Α-fe<sub>2</Sub>o<sub>3< Surface Decoration: Synthesis, Characterization, and Performance Evaluation(Elsevier Sci Ltd, 2024) Doluel, Eyyup Can; Kartal, Ugur; Uzunbayir, Begum; Erol, Mustafa; Yurddaskal, Metin; Pulat, Gunnur; Guler, SaadetElectrochemical anodization, under a constant voltage of 45 V and for 15, 30, and 45 min, was performed to fabricate highly ordered TiO2 nanotubes. Depending on the processing paramters, the diameter of the TiO2 nanotubes was found to be around 95 +/- 6 nm, while the thickness of TNT layer exhibited a change with anodizing time, varying from 1 to 4 mu m. Subsequent to the anodization alpha-Fe2O3/TiO2 heterogeneous structure was created by the spin coating of iron precursor based solutions on TiO2 nanotubes. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were utilized to ascertain the phase structure and morphology of TiO2 nanotubes. The change of optical band gap values depending on the processing parameters was calculated using UV-Vis spectrophotometer data. The photocatalytic performances of the samples, namely the degradation rates and kinetics, were evaluated by examining the photodegradation of methylene blue (MB). The (TC15) sample, obtained by anodizing for 15 min and decorated with alpha-Fe2O3, exhibited the highest photocatalytic activity, with a degradation efficiency of 70 % at the end of 7 h of light exposure. On the other hand, the inhibition percentages of bacterial growth were examined and it was seen that the TC30 sample with the highest value was 88.89 % for E.coli bacteria and 70.57 % for S.aureus. To assess the mechanism of antimicrobial activity, ROS (Reactive Oxygen Species) Analysis were perfomed on T30 and TC30 groups and the ROS amount of TC30 was higher than T30. According to the results of the L929 mouse fibroblast cytotoxicity experiment with indirect contact according to ISO 10993-5 standards, all samples showed a successful performance in terms of cell viability. The cell viability of TC15 was higher in comparison to the control group.Article Citation - WoS: 389Citation - Scopus: 463Antibacterial and Antioxidant Activity of Essential Oil Terpenes Against Pathogenic and Spoilage-Forming Bacteria and Cell Structure-Activity Relationships Evaluated by Sem Microscopy(MDPI Multidisciplinary Digital Publishing Institute, 2014) Zengin, Hatice; Baysal, Ayşe HandanThe antibacterial activity and antioxidant effect of the compounds α-terpineol, linalool, eucalyptol and α-pinene obtained from essential oils (EOs), against pathogenic and spoilage forming bacteria were determined. The antibacterial activities of these compounds were observed in vitro on four Gram-negative and three Gram-positive strains. S. putrefaciens was the most resistant bacteria to all tested components, with MIC values of 2% or higher, whereas E. coli O157:H7 was the most sensitive strain among the tested bacteria. Eucalyptol extended the lag phase of S. Typhimurium, E. coli O157:H7 and S. aureus at the concentrations of 0.7%, 0.6% and 1%, respectively. In vitro cell growth experiments showed the tested compounds had toxic effects on all bacterial species with different level of potency. Synergistic and additive effects were observed at least one dose pair of combination against S. Typhimurium, E. coli O157:H7 and S. aureus, however antagonistic effects were not found in these combinations. The results of this first study are encouraging for further investigations on mechanisms of antimicrobial activity of these EO components.Article Citation - WoS: 35Citation - Scopus: 40Antibacterial and Bactericidal Activity of Nitric Oxide-Releasing Natural Zeolite(Elsevier Ltd., 2010) Narin, Güler; Bulut Albayrak, Çisem; Ülkü, SemraThe zeolitic tuff from Gördes (Western Anatolia) was used as adsorbent for nitric oxide (NO) storage and release purposes. The NO loading of the zeolite was performed under 20mLmin -1 NO flow at 30°C and then the zeolite was purged with inert gas in order to remove the species that were reversibly adsorbed and in the gas phase (desorption). The total and reversible adsorption capacities of the zeolite were determined from the adsorption and desorption breakthrough curves, respectively. The NO-loaded zeolite exhibited antibacterial and bactericidal activities against Gram-negative (Escherichia coli) and Gram-positive bacteria (Bacillus subtilis) under physiological conditions. From the NO release kinetics, the diffusion coefficient of NO in the zeolite particle was determined. © 2010 Elsevier B.V.Article Citation - WoS: 249Citation - Scopus: 268Silver, Zinc, and Copper Exchange in a Na-Clinoptilolite and Resulting Effect on Antibacterial Activity(Elsevier Ltd., 2004) Top, Ayben; Ülkü, SemraAg+-Na+, Zn2+-Na+, and Cu2+-Na+ equilibria for clinoptilolite-rich mineral from Gördes (Western Anatolia) were investigated at 25 °C and 0.1 N total solution normality. While silver exchange was favorable over the whole concentration range, zinc and copper were partially exchanged and preferred only at low concentrations. The standard free energies of exchanges for Ag+-Na+, Zn2+-Na+, and Cu2+-Na+ pairs were found as -6.0, 2.03, and 3.09 kJ/equiv., respectively. From these values, selectivity sequence was determined as Ag+>Na+ >Zn2+>Cu2+. Antibacterial activities of the exchanged samples were measured as a function of exchange level against Pseudomonas aeruginosa and Escherichia coli. Considering the selectivity sequence of the clinoptilolite and antibacterial activity results, Ag-clinoptilolite seemed to be promising antibacterial material.