https://hdl.handle.net/20.500.12619/919 2026-05-05T14:30:18Z https://hdl.handle.net/20.500.12619/33376 The evaluation of the genotoxicity of two food preservatives: Sodium benzoate and potassium benzoate Yılmaz, Saim; Aksoy, Hüseyin; Yılmaz, Şenol In this study, the genotoxic effects of sodium benzoate (SB) and potassium benzoate (PB) were investigated in cultured human peripheral lymphocytes using chromosomal aberrations (CA), sister chromatid exchange (SCE), and micronuclei (MN). The level of nuclear DNA damage of SB and PB were also evaluated using the comet assay. The lymphocytes were incubated with different concentrations of SB (6.25, 12.5, 25, 50, and 100 mu g/ml) and PB (62.5, 125, 250, 500, and 1000 mu g/ml). A significant increase was observed in CA. SCE, and MN, in almost all treatments compared to negative controls. SB and PB significantly decreased the mitotic index (MI) in all the treatments, compared to the negative controls. However, neither of the additives affected the replication index (RI). Although SB significantly increased DNA damage, PB did not cause a significant increase in DNA damage. The present results indicate that SB and PB are clastogenic, mutagenic and cytotoxic to human lymphocytes in vitro. (C) 2010 Elsevier Ltd. All rights reserved. 2011-01-01T00:00:00Z https://hdl.handle.net/20.500.12619/33382 Composting of sewage sludge with mole cricket: stability, maturity and sanitation aspects Özdemir, Serdar; Dede, Gülgün; O. H. Dede; S. M. Turp The composting of sewage sludge is constrained by structural insufficiencies such as high water retention, reduced free air space and limited compaction. To overcome these hindrances, this study investigates application of bioconversion method to compost sewage sludge. The bioconversion method uses insect mole cricket that provides benefits such as improved aeration by 32%, enhanced organic matter transformation, stability and maturity of the end product. Bioconversion method was compared with vermicomposting and conventional aerated composting methods. Comparison of the results among the three methods showed that the end product was mature with germination index (GI) > 80%, humification index (E4/E6) < 8, dissolved organic carbon < 10 mg kg(-1) and C/N < 15. However, the end product of the bioconversion method had the highest GI of 140, cation exchange capacity of 91.7 and the lowest C/N ratio of 14 indicating that this compost was relatively more stable than the composts produced by the other two methods. The number of faecal coliforms in mature compost samples was 210, 230 and 750 CFU g(-1) for the bioconversion, vermicomposting and conventional composting methods, respectively. The results highlight that bioconversion method produces a non-phytotoxic and microbiologically safe compost that can be considered as a reliable alternative for composting of sewage sludge. 2019-01-01T00:00:00Z https://hdl.handle.net/20.500.12619/33377 Genotoxic effects of chlorophenoxy herbicide diclofop-methyl in mice in vivo and in human lymphocytes in vitro Yılmaz, Saim; Aksoy, Hüseyin; Yılmaz, Şenol Diclofop-methyl (DM) is a chlorophenoxy derivative used in large quantities for the control of annual grasses in grain and vegetable crops. In this study, the genotoxic effects of DM were investigated by measuring chromosomal aberrations (CAs) in mouse bone-marrow cells and CA and the comet assay in human peripheral lymphocytes. Mice were treated with 15.63, 31.25, 62.5, and 125 mg/kg body weight of DM intraperitoneally for 24 hours, and 15.63-, 31.25-, 62.5-, 125-, and 250-mu g/mL concentrations were applied to human lymphocytes for both 24 and 48 hours. In in vivo treatments, DM significantly, but not dose dependently, increased the total chromosome aberrations, compared to both negative and solvent controls. Cell proliferation was significantly, but not dose dependently, affected by all doses. In in vitro treatments, DM (except 15.63 mu g/mL) significantly and dose dependently increased the frequency of chromosome aberrations. Also, 250 mu g/mL of 48-hour treatment was found to be toxic. Cell proliferation was significantly and dose dependently affected by DM applications, when compared to negative control. In in vitro treatments, DM significantly decreased the mitotic index only at the highest concentration for 24 hours, and 62.5- and 125-mu g/mL concentrations for 48 hours. In the comet assay, a significant and dose-dependent increase in comet-tail intensity was observed at 62.5-, 125-, and 250-mu g/mL concentrations. The mean comet-tail length was significantly increased in all concentrations. Our results demonstrate that DM is genotoxic in mammalian cells in vivo and in vitro. 2011-01-01T00:00:00Z https://hdl.handle.net/20.500.12619/33378 The effect of SiC addition on the crystallization kinetics of atmospheric plasma sprayed basalt-based coatings Yılmaz, Şenol; Ercenk, Ediz; Şen, Uğur; Yılmaz, Saim The crystallisation kinetics of the conversion of a glass coating layer made from a mixture of natural basalt volcanic rock and SiC into glass-ceramic have been investigated. The process depends on the crystallisation temperature, time and amount of the SiC added. Coating powders were prepared from pure basalt and from basalt containing 10-50 wt% SiC. The powders were coated by an atmospheric plasma spray technique on the pre-coated AISI 1040 steel substrate with Ni-Al. The coating layer was vitrified by sudden cooling. The amorphous structure of the coatings was verified by X-ray diffraction (XRD) analysis. To obtain glass-ceramic, coatings were subjected to crystallisation heat treatment in an argon atmosphere. Crystallisation heat treatment temperatures of 800 degrees C, 900 degrees C and 1000 degrees C were chosen by using DTA. After the heat treatment process, augite, ferrian-diopsite, diopside, albite, andesine, and moissonite phases formed in the coating layer and were verified by XRD analysis. The crystallisation activation energies were determined to be between 323.4 kJ/mol and 253.2 kJ/mol, depending on SiC addition. The crystallisation activation energies decreased with increasing amounts of SiC addition. The Avrami parameters of the crystallisation process varied between 1.60 and 3.33, which indicates that internal crystallisation dominated for all of the compositions. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved. 2012-01-01T00:00:00Z