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Öğe Evaluation of polyphenol contents in differently processed apricots using accelerated solvent extraction followed by high-performance liquid chromatography-diode array detector(Taylor & Francis Ltd, 2011) Erdogan, Selim; Erdemoglu, SemaConcentrations of 17 polyphenols in ripe-fresh, sun-dried and sulfited-dried apricots either harvested from organic or pesticide-treated trees before harvest were determined using reverse-phase high-performance liquid chromatography with UV-Vis diode array detector, and the change of polyphenol profile with origin of the apricot product was established. Extraction of polyphenols was achieved using the accelerated solvent extraction technique (ASE). A mixture of methanol, water (70:30 v/v) including 0.1 g of tert-butylhydroquinone as solvent, 60 min extraction time, 60 degrees C temperature and 1,500 psi pressure were found the most productive operating conditions for ASE. Concentrations of polyphenols in organic apricots were higher than pesticide-treated samples, and roughly the same in ripe-fresh and sun-dried apricots. Polyphenol concentrations of either organic or pesticide-treated sulfited-dried apricots were lower than the ripe-fresh apricots. Considering the organic ripe-fresh apricots, there was a decrease in some polyphenol concentration in the sulfited-dried apricots compared with the ripe-fresh apricot, and the range of decrease is between 1.4 and 53%.Öğe Evaluation on reducing toxicity of fluoxastrobin with doped TiO2 nanoparticles(Tubitak Scientific & Technological Research Council Turkey, 2021) Gungordu, Abbas; Ozmen, Nesrin; Erdemoglu, Sema; Turhan, Duygu Ozhan; Asilturk, Meltem; Akgeyik, Emrah; Ozmen, MuratIn this study, toxic effects caused by the degradation of fluoxastrobin, which is a commonly used fungicide where newly synthesized manganese or sulfur-doped TiO2 nanoparticles exist were evaluated. The characterization study of nanoparticles was performed by scanning an electron microscopy (SEM), X-ray diffractometry, Brunau-Emmet-Teller analysis, X-ray fluorescence spectroscopy, and UV-Vis (ultraviolet-visible) reflectance spectra. Subsequently, the photocatalytic performance of nanoparticles, their toxicity, and the photocatalytic degradation products of fluoxastrobin with the same nanoparticles were tested during the two development stages of Xenopus laevis. The LC(50)s of fluoxastrobin were determined on test organisms, and a 5 mg L-1 fluoxastrobin was selected to evaluate the photocatalytic degradation capacity due to toxicity studies. The sublethal effects of the nanoparticles and the degradation product of fluoxastrobin were assessed with embryonic malformations and biochemical marker responses. Sulfur-doped TiO2 was found to be more effective compared to manganese-doped TiO2 for the degradation of fluoxastrobin, photocatalytically. On the other hand, even if the tested nanoparticles were not lethal, they caused effects such as growth retardation and changes in biochemical responses on organisms.Öğe Magnetoelastic Humidity Sensors with TiO2 Nanotube Sensing Layers(Mdpi, 2020) Atalay, Selcuk; Izgi, Tekin; Kolat, Veli Serkan; Erdemoglu, Sema; Inan, Orhan OrcunIn this study, TiO2 nanotubes (TiO2-NTs) are coated with a drop-casting method on Fe40Ni38Mo4B18 amorphous ferromagnetic ribbons and the humidity response of the prepared magnetoelastic sensors (MES) is investigated. The synthesis of TiO2-NTs is performed using a hydrothermal process. Sample characterization is carried out using X-ray diffraction and scanning electron microscopy. The results show that the sensors can measure moisture values in the range of 5% to 95% with very high precision and very low hysteresis. The humidity variation between 5% and 95% shows a change in the sensor resonance frequency of 3180 Hz, which is a significant change compared to many magnetoelastic humidity sensors developed so far.Öğe 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, SemaPhotocatalytic 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] .Öğe Photocatalytic degradation of azo dye using core@shell nano-TiO2 particles to reduce toxicity(Springer Heidelberg, 2018) Ozmen, Nesrin; Erdemoglu, Sema; Gungordu, Abbas; Asilturk, Meltem; Turhan, Duygu Ozhan; Akgeyik, Emrah; Harper, Stacey L.Clean and safe water is fundamental for human and environmental health. Traditional remediation of textile dye-polluted water with chemical, physical, and biological processes has many disadvantages. Due to this, nano-engineered materials are drawing more attention to this area. However, the widespread use of nano-particles for this purpose may lead to photocatalytic degradation of xenobiotics, while increasing the risk of nano-particle-induced ecotoxicity. Therefore, we comparatively evaluated the toxicity of novel synthesized core@shell TiO2 and SiO2 nano-particles to embryonic stages of Danio rerio and Xenopus laevis. The ability of photocatalytic destruction of the synthesized nano-particles was tested using toxic azo dye, disperse red 65, and the effects of reducing the toxicity were evaluated. The reflux process was used to synthesize catalysts in the study. The samples were characterized by scanning electron microscopy, X-ray fluorescence spectroscopy, X-ray diffractometry, BET surface area, and UV-vis-diffuse reflectance spectra. It was determined that the synthesized nano-particles had no significant toxic effect on D. rerio and X. laevis embryos. On the other hand, photocatalytic degradation of the dye significantly reduced lethal effects on embryonic stages of the organisms. Therefore, we suggest that specific nano-particles may be useful for water remediation to prevent human health and environmental impact. However, further risk assessment should be conducted for the ecotoxicological risks of nano-particles spilled in aquatic environments and the relationship of photocatalytic interaction with nano-particles and xenobiotics.Öğe Photocatalytic degradation of Congo Red by hydrothermally synthesized nanocrystalline TiO2 and identification of degradation products by LC-MS(Elsevier, 2008) Erdemoglu, Sema; Aksu, Songuel Karaaslan; Sayilkan, Funda; Izgi, Belgin; Asilturk, Meltem; Sayilkan, Hikmet; Frimmel, FritzDegradation of Congo Red (CR) dye in aqueous solutions was investigated by means of photocatalysis of TiO2 which was hydrothermally synthesized at 200 degrees C in 2 h, in anatase phase with 8 nm crystallite size. Efficiency of TiO2 in photocatalytic degradation under visible irradiation was studied by investigating the effects of amount of TiO2, irradiation time, initial CR concentration and pH. It was found that complete decolorization is achieved within 30 min of irradiation. Effects of nitrate and sulphate ions and humic acid on the degradation were also tested. The results were compared with Degussa P-25 TiO2 at the same degradation conditions. Degradation products were detected using LC-MS technique. The probable pathways for the formation of degradation products were proposed. (C) 2008 Published by Elsevier B.V.Öğe 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, HarunThe 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.Öğe 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, SemaIn 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.Öğe 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, SemaObjectives: 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.Öğe Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO2(Elsevier Science Bv, 2015) Ozmen, Murat; Gungordu, Abbas; Erdemoglu, Sema; Ozmen, Nesrin; Asilturk, MeltemThe toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO2. Undoped and Mn-doped TiO2 nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV-vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO2 was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO2 nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO2 increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2-4 h of degradation. However, biochemical assays showed that both Mn-doped TiO2 and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn-doped TiO2 should be considered due to nanomaterial applications and for spilled nanoparticles in an aquatic ecosystem. Also, the risk of nanoparticles should be considered using indicator reference biochemical markers to verify the environmental health impacts. (C) 2015 Elsevier B.V. All rights reserved.Öğe Use of various agricultural wastes for the removal of heavy metal ions(Inderscience Enterprises Ltd, 2008) Kahraman, Sibel; Dogan, Nukhet; Erdemoglu, SemaThere is a need to develop innovative and alternative technologies that can remove toxic heavy metal pollutants from wastewater. In this Study, two agricultural residues, cotton stalks and apricot seeds, were used to adsorb copper and lead in solutions. Sorption capacities of agricultural wastes were significantly affected by solution pH, adsorbent mass and adsorbent particle size. The adsorption efficiency of two agricultural waste was in the order cotton stalk > apricot seed and the agricultural wastes adsorbed metal ions in the order of Pb > Cu. Treatment of these metals with agricultural wastes reduced their toxic effects on P. aeruginosa. This reduction in toxic effect is important both in respect of environmental biotechnology and waste detoxification. This study has indicated that cotton stalk and apricot seed could be employed as low-cost alternatives in wastewater treatment for the removal of heavy metals.
