Yazar "Osmanoglu, Y. Emre" seçeneğine göre listele

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    The effect of gamma radiation on some succinic acid derivatives in the solid state
    (Elsevier Science Bv, 2017) Sutcu, Kerem; Osmanoglu, Y. Emre
    2,2-dimethyl succinic acid, 2,3-dimethyl succinic acid and monomethyl succinate were exposed to gamma radiation in the form of powder. EPR measurements were carried out to investigate the free radicals produced in all of them, following irradiation. Three of the radical species formed after irradiation were identified and spectroscopic parameters were discussed thereafter. The radical species were attributed to the (C) over dotHCH(2), HOOCCH(CH3)(2)(C) over dotCOOH and H3COOCCH2(C) over dotHCOOH radicals, respectively. The hyperfine splitting constants for all radicals were confirmed by the simulation of the experimental spectra. The radiation sensitivity of the samples was mainly attributed to the EPR line properties of stable radicals. (C) 2016 Elsevier B.V. All rights reserved.
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    Electron paramagnetic resonance study of gamma induced free radicals in single crystal of 1-[2-(1-ethoxy-carbonyl-3-phenylpropylamino)propionyl]octahydrocylo-penta[b]pyrrole-2-carboxylic acid
    (Elsevier, 2020) Osmanoglu, Y. Emre
    The aim of this study was to investigate the structure of the radicals produced by gamma irradiation on single crystals of 1-[2-(1-ethoxy-carbonyl-3-phenyl propyl amino) propionyl]octahydrocylo-penta[b] pyrrole-2-carboxylic acid (C23H32N2O5) by using electron paramagnetic resonance spectroscopy technique. The radiation-induced free radical of single crystals was studied at the temperatures between 120 and 300 K and it has been found that gamma-irradiation produced the C gamma H2C beta H2CNH(COOC2H5) radicals. The hyperfine coupling constants and the g value of the free radical was reported as A(C beta H2C gamma H)(2) = 1.37 mT, a(N) = 1.10 mT and g = 2.0061. The free radical formed in compound was observed to be stable at 300 K during two months of gamma-irradiation. The results were observed as being in good conformity with the existing literature. (C) 2019 Elsevier B.V. All rights reserved.
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    Electron spin resonance identification of gamma irradiated 2,4?-dichlorodiphenyl dichloroethane and 6-mercaptopurine monohydrate in the solid state
    (Elsevier Science Bv, 2018) Sutcu, Kerem; Osmanoglu, Y. Emre
    The purpose of this study is to investigate the effects of ionizing radiation on two anticancer drugs, 2,4'-dichlorodiphenyl dichloroethane (DCP) and 6-mercaptopurine monohydrate (MPM), by using electron spin resonance (ESR) spectroscopy. For that purpose the intensity of ESR signals of the samples as a function of the microwave power was investigated in the range of 0.01-100 mW at room temperature. While unirradiated samples presented no ESR signal, irradiated samples exhibited significant ESR spectra. ESR measurements were performed at low and high temperatures to study the dosimetric features of free radicals induced by gamma irradiation. In order to obtain the dose-response curves, samples irradiated with gamma at 1, 5, 10, 15, 20, and 25 kGy dose values were used. Furthermore, the g values of the radicals and the hyperfine coupling constants were also determined. Additionally, the time dependency of the samples was analyzed to study the stability of the radicals. (C) 2018 Elsevier B.V. All rights reserved.
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    EPR investigation of gamma-irradiated L-citrulline, ?-methyl-DL-serine, 3-fluoro-DL-valine and N-acetyl-L-cysteine
    (Elsevier, 2017) Osmanoglu, Y. Emre; Sutcu, Kerem; Baskan, M. Halim
    The spectroscopic parameters of the paramagnetic species produced in gamma-irradiated L-citrulline, alpha-methyl-m-serine, 3-fluoro-DL-valine and N-acetyl-L-cysteine were investigated at room temperature at a dose of 20 kGy by using EPR technique. The paramagnetic species were attributed to NH2CONH(CH2)(3)CNH2COOH, HOCH2CCH3COOH and HOCHCCH3NH2COOH, CH3CH3CCHNH2COOH and SHCH(2)GNHCOCH(3)COOH radicals, respectively. EPR data of the unpaired electron with the environmental protons and N-14 nucleus were used to characterize the contributing radicals produced in gamma irradiated compounds. In this paper, the stability of these compounds at room temperature after irradiation was also studied. (C) 2016 Elsevier B.V. All rights reserved.
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    EPR studies of the free radicals generated in gamma irradiated amino acid derivatives
    (Elsevier Science Bv, 2017) Osmanoglu, Y. Emre; Sutcu, Kerem
    Gamma irradiated powder forms of N-acetyl-DL-aspartic acid, N-carbamoyl-DL-aspartic acid and N-methyl-L-serine were investigated by electron paramagnetic resonance spectroscopy (EPR) at room temperature. In these compounds, the paramagnetic centers formed after irradiation were attributed to the HOOCCH2(C)over dotHCOOH, COOH(C)over dotHCHNH and HOCH2(C)over dotHCOOH radicals, respectively. The g values and the hyperfine coupling constants for the radical species are with values of g = 2.0038 +/- 0.0005, a(alpha) = 2.15 mT, a(beta)((1)) = 3.84 mT and a(beta)((2)) = 2.15 for the first radical, g = 2.0039 +/- 0.0005, a(alpha) = 1.7 mT, a(beta)((1)) = 0.62 mT, a(beta)((2)) = 0.54 mT, a(gamma) = 0.53 mT for the second radical and g = 2.0039 +/- 0.0005, a(beta)((1)) = 2.40 mT, a(beta)((2)) = 1.83 mT and a(alpha) = 1.83 mT for the third radical. The free radicals formed in three compounds were found to be stable for three months at room temperature. It was concluded that, spin density was concentrated predominantly in the 2p(pi) orbital of the carbon atom. (C) 2017 Elsevier B.V. All rights reserved.
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    EPR STUDY OF FREE RADICALS IN AMINO ACIDS DERIVATIVES IRRADIATED BY GAMMA RAYS
    (Editura Acad Romane, 2011) Aydin, M.; Osmanoglu, Y. Emre
    Exposure of powders forms of DL-arginine hydrochloride and glycine hydrochloride to gamma radiation results in the formation of free radicals detected by electron paramagnetic resonance spectroscopy at room temperature. The observed radicals were assigned to be NH2(NH)NHCHCH2CH2CH(NH2)COOH and (NH3+) CHCOO- respectively. The g values and the hyperfine coupling constants of the unpaired electron with the environmental protons and N-14 nucleus were determined for these two radicals. These results were compared with the earlier studies on amino acid derivatives.
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    EPR Study of Gamma Induced Radicals in Amino and Iminodiacetic Acid Derivatives
    (Soc Brasileira Fisica, 2009) Aydin, Murat; Baskan, M. Halim; Osmanoglu, Y. Emre
    In this study, electron paramagnetic resonance spectroscopy was used to investigate free radicals formed in gamma irradiated L-glutamine hydrochloride, iminodiacetic acid hydrochloride and N-(2-hyroxyethyl) iminodiacetic acid powders. The free radicals produced in L-glutamine hydrochloride powders were attributed to the CH(2)(C) over bar HCOOH radical; and those in iminodiacetic acid hydrochloride and N-(2-hyroxyethyl) iminodiacetic acid powders to the HNCHCH(2)(COOH)(2) and HOCH(2)CH(2)N (C) over bar HCH(2)(COOH)(2), respectively. The g-values of the radicals and the hyperfine structure constants of the free electron with the environmental protons and (14)N nucleus were determined. The samples were not displayed before they were not irradiated. The free radicals were found stable at room temperature for more than six months. Some spectroscopic properties and suggestions concerning possible structure of the radicals are discussed in this paper.
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    ESR study of some gamma irradiated amino acids and condensed 1,4-dihydropyridines
    (Elsevier Science Bv, 2013) Aydin, Murat; Simsek, Rahime; Gunduz, Miyase Gozde; Safak, Cihat; Osmanoglu, Y. Emre
    L-alanine methyl ester hydrochloride, 2-aminoisobutyric acid and some condensed 1,4-dihydropyridine derivatives (Compounds R1-R4) were gamma irradiated, the induced free radicals was investigated at room temperature by electron spin resonance techniques. The observed paramagnetic species of amino acids compounds were attributed to the CH3<(C)over dot>HCOOCH3 and (CH3)(2)<(C)over dot>COOH radicals, respectively. The observed spectra of the 1,4-dihydropyridine derivatives interpreted in terms of some type of amine radical fragments. The spectra were computer simulated and the g values of the radicals and the hyperfine structure constants of the unpaired electron with nearby protons and N-14 nucleus were determined. In this study, the observed paramagnetic species were found to be stable at room temperature more than 2 months. Published by Elsevier B.V.
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    Radiation effect studies in single crystal of Trifluoroacetyl-?-Aminoisobutyric acid
    (Taylor & Francis Ltd, 2015) Baskan, M. Halim; Osmanoglu, Y. Emre; Sutcu, K.; Aydin, M.; Osmanoglu, S.
    In this study, electron paramagnetic resonance of -irradiated single crystals of N-Trifluoroacetyl--amino isobutyric acid (F3Ac-Aib-OH) was investigated at room temperature and analyzed for different orientations of the crystal in the magnetic field. The paramagnetic species in N-Trifluoroacetyl--aminoisobutyric acid was attributed to the CF2-R radical (R= CONHC(CH3)COOH). Hyperfine coupling constants and g value were also determined. In addition, the single crystal of F3Ac-Aib-OH was UV-irradiated and paramagnetic species formed was studied at room temperature. The effects of gamma irradiation on fluoroamino acid and stability were discussed.
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    Radiation effect studies on some glycine derivatives in solid state
    (Taylor & Francis Ltd, 2017) Osmanoglu, Y. Emre; Sutcu, Kerem; Osmanoglu, Semsettin
    Five glycyl derivatives, glycyl-L-histidine, L-alanyl-glycine, glycine hydrochloride, gly-gly hydrochloride and, gly-gly-glycine in powder form were exposed to 20kGy doses of Co-60 gamma radiation to study the effects of ionizing radiation. In these compounds, the paramagnetic centers formed after irradiation were attributed to the RNHCHCO-OH, CH2CHNH, H2NCH2CO-OHHCl, NH2CHCONHCH2COOHHCl and HNCH2CO-OH radicals, respectively. The effect of gamma irradiation to the radical structures and time stability of the radicals were investigated by EPR spectroscopy. The spectra were computer simulated and the hyperfine coupling constants were determined.
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    Structure and behaviour of the free radicals generated in gamma irradiated amino acid and iminodiacetic acid derivatives
    (Pergamon-Elsevier Science Ltd, 2011) Osmanoglu, Semsettin; Aydin, Murat; Osmanoglu, Y. Emre; Dicle, I. Yesim; Baskan, M. Halim
    An EPR study has been carried out to investigate the structure and behaviour of the free radical formed gamma-irradiated L-alaninamide hydrochloride, DL-glutamic acid monohydrate and N-(2-carboxyethyl) iminodiacetic acid powders at room temperature. The observed paramagnetic species have been attributed to the CH3CHCONH2, HOOCCH2CH2CHCOOH and HOOCCH2CH2NCHCH2(COOH)(2) radicals, respectively. Some spectroscopic properties and suggestions concerning possible structure of the radicals were also discussed in this study. Published by Elsevier B.V.