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Öğe Accelerated formation of BaTiO3 ceramics with mechanochemical processing in different liquids(Elsevier Science Sa, 2017) Akbas, Hatice Zehra; Aydin, Zeki; Guder, Ferhat; Turgut, SelvinBaTiO3 powders were synthesized from BaCO3 and TiO2 with mechanochemical processing using a shaker by solid-state reactions in distilled water, methanol, and acetone. Decomposition of BaCO3, disproportionation of the liquids and hydrous titanium oxide are led to formation of the BaTiO3 ceramics. The liquids are accelerated the formation of BaTiO3 dependent on the O-H bands of the liquids structure. More O-H bands increased the density of the calcined powders, and improved the microstructure of sintered BaTiO3 ceramics. The density of the calcined powders is 4.67, 3.66, and 3.49 g/cm(3) for the water, methanol, and acetone respectively. X-ray Diffraction (XRD) and Raman spectroscopy analysis were verified the structure of BaTiO3. The differences of the microstructure are clearly shown that the micrographs of sintered pellets by Scanning Electron Microscopy (SEM). Depending on the liquid, the process led directly to normal and abnormal grain growth of the sintered samples. (C) 2016 Elsevier B.V. All rights reserved.Öğe Analysis of methanol and its derivatives in illegally produced alcoholic beverages(Elsevier Sci Ltd, 2015) Arslan, M. Mustafa; Zeren, Cem; Aydin, Zeki; Akcan, Ramazan; Dokuyucu, Recep; Keten, Alper; Cekin, NecmiIntroduction: Illegal alcohol production remains as a common issue worldwide. Methanol poisoning mostly occurs because of the methanol used in production of counterfeit alcohol instead of ethyl alcohol due to its low price or by drinking the liquids containing methyl alcohol. Pectolytic enzymes results in an increase of methanol levels in many fermentation products such as ciders or wines. Methanol poisonings are infrequently encountered in forensic medicine practice. However, sporadic cases due to methanol intoxication as well as epidemic cases have been reported. In this study, we aimed to identify existence of methanol and its metabolites in illegally produced alcoholic beverages used in Antakya region. Material and methods: Twelve legally produced alcohol samples and Fifty-six different illegally produced alcohol samples were collected from the markets and local producers. Existence of methanol, formic acid, methyl amine, methyl formate and trioxan were determined using GC-MS method in these samples. Results: Fifty-six different illegal alcohol samples were analyzed in this study and methanol was detected in 39 (75%) of samples. Formic acid was detected in 3, formamide in 1, methyl amine in 6, methyl formate in 10 and trioxan in 2 samples. Conclusion: Overwhelming majority of illegal alcoholic beverages was detected to contain methanol. Interestingly this study also revealed the presence of trioxane, which has not previously reported among toxic agents in illegal alcohol samples. (C) 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.Öğe Biological responses of duckweed (Lemna minor L.) exposed to the inorganic arsenic species As(III) and As(V): Effects of concentration and duration of exposure(2010) Duman, Fatih; Ozturk, Fatma; Aydin, ZekiThe accumulation of arsenic (As) and physiological responses of Lemna minor L. under different concentration (0, 1, 4, 16 and 64 ?M) and duration (1, 2, 4 and 6 days) of two species As, NaAsO2 and Na2HAsO 4•7H2O, were studied in hydroponics. The accumulation of both As species depended on As concentration and exposure duration. The highest accumulation of As was found as 17408 and 8674 ?g g-1, for plants exposed to 64 ?M of As(III) and As(V), respectively, after 6 days. Two-way ANOVA analyses indicated that, for plants exposed to arsenite (As(III)), exposure duration had a greater effect than concentration on As accumulation. Conversely, exposure concentration had a greater effect on As accumulation in plants exposed to arsenate (As(V)). Arsenic exposure levels, approaching 16 ?M for As(III) and 64 ?M for As(V), did not significantly affect EC values. Beyond these exposure concentrations, EC values increased in a manner that depended on duration. Significant effect of As(III) on lipid peroxidation was observed at 1 ?M application whereas, this effect started to be significant after an exposure to 16 ?M As(V). For both As(III) and As(V), photosynthetic pigment levels slightly increased for the first day with respect to the control, followed by a gradual decline at higher concentrations and durations. An increase in protein content and enzyme activity was observed at moderate exposure conditions, followed by a decrease. Significant positive correlations were determined between accumulated As and ion leakage and lipid peroxidation. Negative correlations were found between accumulated As and total chlorophyll and protein content. Our results suggested that exposure duration and concentration had a strong synergetic effect on antioxidant enzyme activity. The findings of the present study may be useful when this plant is used as a phytoremediator in arsenic-polluted water. © 2010 Springer Science+Business Media, LLC.Öğe Effects of Exogenous Glycinebetaine and Trehalose on Cadmium Accumulation and Biological Responses of an Aquatic Plant (Lemna gibba L.)(Springer International Publishing Ag, 2011) Duman, Fatih; Aksoy, Ahmet; Aydin, Zeki; Temizgul, RidvanThis study aimed to investigate and compare the effects of exogenous glycinebetaine (GB) and trehalose (TR) on the biological responses of duckweed (Lemna gibba L.) against cadmium (Cd) accumulation. Duckweed samples were exposed to 0.5, 1, and 3 mM of Cd for 6 days in the presence and absence of GB (0.5, 1, 2, and 5 mM) or TR (0.5, 1, 2, and 5 mM). The accumulation of Cd, GB, and TR were investigated, and their influence on the rates of lipid peroxidation, photosynthetic activity, proline content and enzymatic antioxidant performance was examined. Two-way ANOVA showed that exposure to Cd and/or GB or TR caused an increase in Cd accumulation concentration dependently. TR had significant effects on Cd accumulation. The application of 0.5 mM TR increased Cd accumulation, whereas 5 mM decreased Cd accumulation. However, Cd accumulation was not significantly affected by the presence of GB. Cd concentration alone or in combination with GB or TR had a significant effect on lipid peroxidation, photosynthetic activity, proline content, and antioxidant enzyme activities. In addition, statistically significant GB-Cd and TR-Cd interactions were observed. We conclude that both GB and TR play protective roles against Cd stress in aquatic plants. The use of a low level of TR (i.e., 0.5 mM) may be more useful than GB in phytoremediation studies.Öğe Effects of ultrasonication and conventional mechanical homogenization processes on the structures and dielectric properties of BaTiO3 ceramics(Elsevier Science Bv, 2017) Akbas, Hatice Zehra; Aydin, Zeki; Yilmaz, Onur; Turgut, SelvinThe effects of the homogenization process on the structures and dielectric properties of pure and Nb-doped BaTiO3 ceramics have been investigated using an ultrasonic homogenization and conventional mechanical methods. The reagents were homogenized using an ultrasonic processor with high-intensity ultrasonic waves and using a compact mixer-shaker. The components and crystal types of the powders were determined by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses. The complex permittivity (epsilon', epsilon'') and AC conductivity (sigma') of the samples were analyzed in a wide frequency range of 20 Hz to 2 MHz at room temperature. The structures and dielectric properties of pure and Nb-doped BaTiO3 ceramics strongly depend on the homogenization process in a solid-state reaction method. Using an ultrasonic processor with high-intensity ultrasonic waves based on acoustic cavitation phenomena can make a significant improvement in producing high-purity BaTiO3 ceramics without carbonate impurities with a small dielectric loss. (C) 2016 Elsevier B.V. All rights reserved.Öğe Iodine, copper, zinc, selenium and molybdenum levels in children aged between 6 and 12 years in the rural area with iodine deficiency and in the city center without iodine deficiency in Hatay(Aves, 2014) Celik, Tanju; Savas, Nazan; Kurtoglu, Selim; Sangun, Ozlem; Aydin, Zeki; Mustafa, Didin; Ozturk, Oktay HasanAim: Thyroid diseases related with iodine deficiency are observed commonly in our country and in the world. In this study, we aimed to investigate iodine deficiency in urine and selenium, zinc, copper or molybdenum deficiencies which may accompany this in children aged between 6 and 12 years in two schools in the province of Hatay (endemic goitre region). Material and Methods: This study is a case-control field-study in which students aged between 6 and 12 years were included. One hundred fourteen subjects from the village of Tanisma related to the center of our province and 100 subjects from the city center of Hatay (Antakya) were included in the study. Iodine, selenium, zinc, copper and molybdenum levels were measured in the urine samples of the students included in the study. Results: Iodine deficiency was found with a severe (5%), moderate (18.4%) and mild degree (43%), respectively in the village of Tanisma. Mild iodine deficiency (7%) was found in the center of Hatay. No moderate and severe iodine deficiency was found in the control group. A significant difference was found between the groups in terms of urine iodine excretion (p < 0.001). A significant correlation was found between the levels of iodine, selenium, zinc and molybdenum (p < 0.05). A moderately positive correlation was found between iodine and selenium (p < 0.001). A moderately positive correlation was found between iodine and zinc levels (p < 0.001) and a weak correlation was found between iodine and molybdenum (p < 0.01). No significant correlation was found between iodine level and copper level (p > 0.05). Conclusions: Selenium and zinc deficiency may accompany iodine deficiency. Selenium and zinc deficiency should be considered in individuals who are found to have iodine deficiency especially in endemic goitre regions.Öğe Structural Differences of BaTiO3 Ceramics Modified by Ultrasonic and Mechanochemical Methods(Springer, 2018) Aydin, Zeki; Turgut, Selvin; Akbas, Hatice ZehraBarium titanate powders were synthesized by the modified solid-state method with ultrasonic (5 min) and mechanochemical (12 h) deagglomeration methods. The structure of the samples was verified using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometer (XRD). Scanning electron microscopy (SEM) analysis of the powders showed that using ultrasonic deagglomeration significantly decreased the particle size with perfect homogeneity in the shortest time. The particle size of the powders was calculated as 44.7 nm and 80.4 nm for ultrasonic and mechanochemical deagglomeration, respectively. The sintered pellet by ultrasonic method had no abnormal grain growth, and the grain sizes were between 10 and 30 m. The pellet by mechanochemical method had an abnormal grain growth, and the grain sizes were between 10 and 100 m. The results showed that ultrasonication remarkably improved the structure of the samples in the shortest time.
