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    Determination of some trace and heavy elements, in vitro antioxidant activity, total phenolic and Phenethyl isothiocyanate content in Watercress from Turkey
    (United Arab Emirates Univ, 2022) Uyumlu, Ayse Burcin; Yilmaz, Hatice Caglar
    The purpose of this study was to define the content of total phenolic and phenylethyl isothiocyanate, the in vitro antioxidant activity, and the content of Trace and Heavy Elements of watercress (Nasturtium officinale R. Br., Brassicaceae). It has ecological and economic importance and has been used by humans for many years both for food and medical purposes. Now it is reported to have a chemopreventive effect. In this study, Watercress samples were collected from Malatya, Turkey. Spectrophotometric methods were used to determine the antioxidant activity and the content of total phenolic and phenylethyl isothiocyanate. To determine heavy metals and trace elements watercress were used inductively coupled plasma-mass spectrometry (ICP-MS). Our results indicated that the extract of watercress has a high antioxidant capacity. This feature was related to phenolic compounds and phenylethyl isothiocyanate. Our analysis with ICP-MS has revealed that the watercress plant has high iron content and toxic heavy metals did not bioaccumulate in the watercress plant. So it is recommended to consume the watercress plant as food according to these results. However, toxicity studies should be carried out in living beings regarding plant intake.
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    Investigation of the effects of metal oxide nanoparticle mixtures on Danio rerio and Xenopus laevis embryos
    (Taylor & Francis Ltd, 2023) Ozmen, Nesrin; Turhan, Duygu Ozhan; Gungordu, Abbas; Yilmaz, Hatice Caglar; Ozmen, Murat
    In this study, the toxic effects of single TiO2, ZnO and Fe2O3 nanoparticles (NPs) and their binary and ternary combinations on the embryonic development of Xenopus laevis and Danio rerio were evaluated. It was aimed to determine the median lethal concentrations, growth retardation and developmental malformation effects and the effects of mixed nanoparticle exposure to selected enzyme biomarkers resulting from the exposure of embryos to NPs. The results showed that ZnO NPs, which are the most toxic according to the highest lethality level, cause developmental delay and malformations. The Fe2O3 and TiO2 NPs caused growth retardation only in D. rerio embryos. It was determined that double and triple combinations of NPs did not cause significant lethality in both species. Biochemical markers showed that mixed NPs could lead to greater toxicity compared to single exposures. The results also revealed that TiO2 or Fe2O3 NPs caused an increase in toxicity when co-existing with ZnO NP due to additive effects. Overall, the results showed that D. rerio was more susceptible to NP exposure in terms of growth and mortality than X. laevis. However, studies that are more comprehensive are needed to better understand the toxicity mechanism of metal oxide NP mixtures.
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    Photocatalytic degradation of amoxicillin using Co-doped TiO2 synthesized by reflux method and monitoring of degradation products by LC-MS/MS
    (Taylor & Francis Inc, 2020) Yilmaz, Hatice Caglar; Akgeyik, Emrah; Bougarrani, Salma; El Azzouzi, Mohammed; Erdemoglu, Sema
    Photocatalytic degradation of Amoxicillin (AMX) in aqueous solution by Co-doped TiO2 and undoped TiO2 synthesized by reflux route was investigated. The catalysts were characterized using X-ray diffractometry, FT-IR spectroscopy, UV-Vis absorption spectroscopy, scanning electron microscopy and X-ray Fluorescence Spectroscopy, and using specific surface area, particle size and zeta potential measurements. Photocatalytic efficiency of Co-doped and undoped TiO2 was compared for degradation of AMX under UV-C and visible irradiation by investigating the effects of the parameters such as percentage of the cobalt doped, amount of catalyst, irradiation time, initial AMX concentration and pH of the medium. Effects of organic and inorganic ions in the aqueous solution were also studied. Results showed that degradation of AMX is improved by Co doping to TiO2. It was detected that complete removal is achieved within 240 min of irradiation under UV-C and 300 min under visible irradiation. 94%, 21% and 16% degradation efficiencies were achieved after 300 min of photocatalysis under visible light in the presence of Co-doped TiO2, undoped TiO2 and Degussa P25 TiO2, respectively. Degradation products were determined and followed using LC-MS/MS technique to describe the evolution of AMX. An attempt was made to estimate the photocatalytic cleavage pathway of AMX by LC-MS/MS [GRAPHICS] .
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    A Rapid Response Humidity Sensor for Monitoring Human Respiration with TiO2-Based Nanotubes as a Sensing Layer
    (Springer, 2020) Atalay, Selcuk; Erdemoglu, Sema; Kolat, Veli Serkan; Izgi, Tekin; Akgeyik, Emrah; Yilmaz, Hatice Caglar; Kaya, Harun
    The use of TiO2-based samples with nanotube (NT) shape for humidity sensing has been investigated. Sample characterization was carried out using x-ray diffraction analysis, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy. x-Ray diffraction analysis showed that the nanotubes had TiO2, NaO3, and H2Ti2O5 phases. SEM revealed that the NTs had diameters ranging from 20 nm to 200 nm and very different lengths. TiO2-based nanotubes were coated using the drop-casting method onto a quartz crystal microbalance (QCM). The synthesis of TiO2-based NTs was performed using a hydrothermal process. Humidity sensing measurements showed that the resonant frequency of TiO2-based NTs deposited onto the QCM was very sensitive to humidity changes. It was also shown that the sensor could be used for respiratory monitoring purposes.
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    Sol-gel synthesis of TiO2 on Co3O4-coated sporopollenin exine microcapsules (SECs) and photocatalytic performance of new semiconductor heterojunction material
    (Springer Heidelberg, 2022) Yilmaz, Hatice Caglar; Atalay, Funda Ersoy; Kaya, Harun; Erdemoglu, Sema
    In this study, a new approach was developed to prepare mesoporous hybrid TiO2/Co3O4 coated on Juglans sporopollenin exine microcapsules (SECs). TiO2 was synthesized on Co3O4-coated SECs used as substrate, by sol-gel method. The obtained semiconductor/semiconductor hetero-junction hybrid materials were characterized with X-ray diffractometry (XRD), UV-Vis absorption spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), particle size distribution, specific surface area, and zeta potential measurements. Photocatalytic performances of hybrid materials were tested for Reactive Black 5 dye under both UV and visible light. Equilibrium pH of the solution containing 10 mg/L Reactive Black 5 dye and 0.1% wt/v TiO2/Co3O4 was around 4.7. After irradiation in the solar box, more than 98% of the Reactive Black 5 was photocatalytically degraded within 60 min.
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    Synthesis of PEITC-loaded gold nanoparticles and evaluation of the hepatoprotective effect on CCl4-induced damage through Nrf2 pathway
    (Walter De Gruyter Gmbh, 2023) Uyumlu, Ayse Burcin; Yilmaz, Hatice Caglar; Satilmis, Basri; Erdemoglu, Sema
    Objectives: The purpose of the study was to prepare an effective and new drug delivery system for enhancing the stability of Phenethyl isothiocyanate (PEITC), and its hepatoprotective effect in the carbon tetrachloride (CCl4)-induced damage in hepatocellular carcinoma G2 (HepG2) cell line via nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway.Methods: Gold nanoparticles were synthesized and then characterized by XRD, SEM, SEM-EDX analysis, hydrodynamic diameter and zeta potential measurements. 1.0024 mM PEITC, a naturally occurring isothiocyanate, an active ingredient was loaded onto the characterized AuNPs. The cytotoxicity test of PEITC-AuNP and effects on ALT, AST, Nrf2 levels and total antioxidant capacity (TAC) of CCI4-induced HepG2 cells were investigated.Results: PEITC-AuNPs and PEITC decreased ALT and AST levels (p < 0.05). This reduction was greater with PEITC-AuNPs. PEITC-AuNPs increased Nrf2 level but it was nonsignificantly (p > 0.05). PEITC didn't increase the Nrf2 level in CCI4-induced HepG2 cells. TAC of both PEITC-AuNPs and PEITC administration increased significantly compared with CCl4 group (p < 0.05). But PEITC-AuNPs enhanced the TAC level higher than PEITC significantly (p < 0.05).Conclusions: PEITC-AuNPs were more effective than PEITC which resulted in more hepatoprotective and antioxidant effects via Nrf2 activation against CCl4-induced liver injury in HepG2 cells.