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Radioprotective thermally generated free-radical dextrins

Chinese Science Bulletin 2008年第7期53卷 984-991页

作者： Piotr TOMASIK Oskar MICHALSKI Ewa BIDZINSKA Antonina CEBULSKA-WASILEWSKA krystyna dyrek Maciej FIEDOROWICZ Pawe OLKO Department of Chemistry Agricultural University Cracow 30149 Poland Jagiellonian University Cracow Poland Institute of Nuclear Physics Cracow Poland

Effect of doses of the X-ray radiation from 0 to 400 Gy upon granular cornstarch and dextrins (British gums, BG) thermally generated from it at 230-300℃ was recognized with quantitative EPR and IR ab-sorption spectroscopy, molecular mass distribution in the depolymerization products, Scanning Elec-tron Microscopy, and X-ray diffractometry. Fractal analysis of the profiles of molecular mass distribu-tion showed that the depolymerization involved debranching of amylopectin. Roasting of cornstarch produced BG which differed in concentration and EPR parameters of stable free radicals from BG generated by X-ray radiation. Two types of stable free radicals, with Gaussian and Lorentzian shapes of EPR signals, were recognized. The shapes of the signals and temperature dependence on free radical intensity indicated exchanging interactions of the antiferromagnetic type, causing partial quenching of the spins at-196℃ (77K). Upon X-ray irradiation, new radicals were generated, the number and stability of which strongly depended on the types of radicals present before irradiation. These radicals slowly ceased because of a repolymerization of BG on storage.

关键词：辐射防护糊精热耦合物理学

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Radioprotectors from pyrodextrins

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Chinese Science Bulletin 2010年第31期55卷 3556-3561页

作者： MICHALSKI Oskar BIDZINSKA Ewa BOROWSKI Micha dyrek krystyna OLKO Pawe STOLARCZYK Liliana SWAKON Jan TOMASIK Piotr WENDA ElZbieta Department of Chemistry and Physics University of Agriculture in Krakow Faculty of Chemistry Jagiellonian University Institute of Nuclear Physics of the Polish Academy of Sciences

Cornstarch heated in the range of 230-280°C depolymerized into pyrodextrins characterized by two-component EPR signals of relatively stable free *** thermally generated radicals could serve as efficient scavengers for free radicals generated from pyrodextrins with the 200 Gy dose of γ-*** most efficient traps/scavengers were produced from cornstarch at 250-280°*** data indicated incorporation of the OH groups to the *** groups most probably originated from the OH· radicals formed by the radiolysis of *** spectra provided evidence for trapping free radicals generated by γ-irradiation and for their subsequent annihilation on contact with *** affected radical processes occurring in pyrodextrins caused by γ-irradiation.

关键词：自由基清除剂玉米淀粉生产 EPR谱信号特征相对稳定双组分拾荒者数据表

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