Browsing by Author "Arisoy K."

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    The effect of zinc supplementation in experimentally induced Toxoplasma gondii infection.
    (1995) Tasçi S.; Sengil A.Z.; Altindis M.; Arisoy K.
    The effect of zinc added diet on cellular immunity in toxoplasmosis was investigated on 50 male wistar albino rats. Total lymphocyte CB8 count were found higher in the infected group when compared to the control group (P < 0.001). The relative increase of CD8 was found to be responsible for the decrease in ratio. In the infected group, there was a slight decrease in CD4 count but it was statistically insignificant. While no significant differences in serum zinc level were observed between the groups, there was a positive correlation with CD8 count in infected group (r = 0.005, P < 0.05). As a result, zinc added diet in toxoplasmosis stimulated the cellular immunity, increased CD8 and total lymphocytes.
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    Deacidification of high acid olive oil by immobilized lipase
    (1996) Makasçi A.; Arisoy K.; Telefoncu A.
    The acidity reduction of high acid oils prior to refining could be an attractive application for industry. In this study the enzymatic deacidification degummed and dewaxed olive oil with a high free fatty acid content, catalysed by an immobilized lipase was optimzed (Novozym 435). The optimum amount of substrate for synthesizing trigliycerides was the necessary stoichiometric amount of fatty acid and glycerol. The mixing was performed with a mechanical stirrer and the dehydration was performed by vacuum pump or by bubbling dry nitrogen. The dehydration rate was faster than the deacidification rate. The four parameters chosen for this experimental plan: pressure, temperature, and the amounts of glycerol and enzyme in the reaction mixture. The use of glycerol more than theortical amount did not affect the rate of deacidification. The stoichiometric amount of glycerol was sufficient for the deacidification of high acid olive oil. Maintaining low pressure is very important for the removal of water which is formed during the esterification reaction. Either, the reaction is conducted at 20 mm Hg or the dehydration is performed by bubbling dry nitrogen. The optimum amount of immobilized enzyme necessary for the deacidification reaction was determined and 10:1 ratio of oil: immobilized enzyme appeared to be satisfactory. The effect of temperature on the deacidification of high acid olive oil was investigated (between 40-70°C). The reaction temperature influenced the rate of deacidification. The optimum operation temperature was found to be 60°C. At 70°C the deacidification decreased with increasing incubation time due to enzyme deactivation occuring at this temperature.
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    Synthesis and some reactions of 4-(ethoxycarbonyl)-1,5-diphenyl- 1H-pyrazole-3-carboxylic acid
    (HeteroCorporation, 2007) Şener A.; Tozlu I.; Genç H.; Bildirici I.; Arisoy K.
    (Chemical Equation Presented) 1,5-Diphenyl-1H-pyrazole-3,4-dicarboxylic acid-4-ethyl ester 2, obtained from the 4-ethoxycarbonyl-5-phenyl-2,3-furandione 1 and N-benzylidene-N1-phenyl hydrazine, was converted via reactions of its acid chloride 3 with various alcohols or N-nucleophiles into the corresponding ester 5 or amide derivatives 6, respectively. In addition, 2 was decarboxylated to give ethyl 1,5-diphenylpyrazole-4-carboxylate 4. Nitrile 7 derivative of 2 was also obtained by dehydration of 6a in a mixture of SOCl 2 and DMF. While cyclocondensation reaction of 2 with hydrazine hydrate leads to the formation of pyrazolo[3,4-d]pyridazine-4,7-dione 8, the reaction of 3 with anhydrous hydrazine provided a new bis pyrazole derivative 9.
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    Oxidative and thermal instability of biodiesel
    (2008) Arisoy K.
    The term biodiesel means the monoalkyl esters of long-chain fatty acids made from biolipids such as vegetable oils, animal fats, or algae. Chemical reactivity of biodiesel can be divided into oxidative and thermal instability. Many of the biolipids contain polyunsaturated fatty acid chains in that their double bonds have high chemical reactivity. The oxidative and thermal degradation occurs on the double bonds of unsaturated aliphatic carbons chains in biolipids. Oxidation of biodiesel results in the formation of hydroperoxides. The formation of the hydroperoxide follows a well-known peroxidation chain mechanism. The olefinic unsaturated fatty acid oxidation is a multi-step reaction process where primary products (conjugated diene hydroperoxides) decompose and chemically interact with each other to form numerous secondary oxidation products. The oxidative and thermal instability are determined by the amount and configuration of the olefinic unsaturation on the fatty acid chains. The viscosity of biodiesel increases with the increase of thermal degradation degree due to the trans-isomer formation on double bonds. The decomposition of biodiesel and its corresponding fatty acids linearly increases from 293 K to 625 K. The densities of biodiesel fuels decreased linearly with temperatures from 293 K to 575 K. The combustion heat of biodiesel partially decreases with the increase of thermal degradation degree.
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    Studies on the antioxidant activity of essential oil and different solvent extracts of Vitex agnus castus L. fruits from Turkey
    (2009) Sarikurkcu C.; Arisoy K.; Tepe B.; Cakir A.; Abali G.; Mete E.
    This study is designed to examine the chemical composition and antioxidant activity of the essential oil and different solvent extracts of Vitex agnus castus. GC and GC-MS analysis was resulted in the detection of 27 components, representing 94.5% of the oil. Major components of the oil were 1,8-cineole (24.98%), sabinene (13.45%), α-pinene (10.60%), α-terpinyl acetate (6.66%), and (Z)-β-farnesene (5.40%). Antioxidant activities of the samples were determined by three different test systems, DPPH, β-carotene/linoleic acid and reducing power assays. In all systems, water extract exhibited excellent activity potential than those of other extracts (hexane, dichloromethane, ethyl acetate and methanol) and the oil. As expected, amount of total phenolics was very high in this extract (112.46 ± 1.22 μg GAEs/mg extract). Dichloromethane extract has been found to be rich in flavonoids. A positive correlation was observed between the antioxidant activity potential and total phenolic and flavonoid levels of the extracts. © 2009 Elsevier Ltd. All rights reserved.
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    Optimization of dolomite ore leaching in hydrochloric acid solutions; [Optymalizacja ługowania rudy dolomitowej w roztworach kwasu solnego]
    (2011) Abali Y.; Bayca S.U.; Arisoy K.; Vaizogullar A.I.
    In this study, the Taguchi method was used to determine the optimum conditions for leaching of dolomite ore in hydrochloric acid solutions. The experimental parameters were leaching temperature, solid-to-liquid ratio, acid initial concentration, leaching time and stirring speed. The following optimum leaching parameter levels were found: temperature 50°C, solid-to-liquid ratio 2%, acid concentration 20 g/cm3 (2 mol/dm3), stirring speed 450 rpm, leaching time 5 min. Under the optimum process conditions, the dolomite ore leaching efficiency was about 83%.