Free radicals in γ-irradiated disodium succinate. Part 1. Monoclinic crystals

1970 ◽  
Vol 48 (18) ◽  
pp. 2804-2808 ◽  
Author(s):  
H. M. Vyas ◽  
J. Janecka ◽  
M. Fujimoto
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Succinic Acid ◽  
Electron Spin ◽  
Room Temperature ◽  
Γ Irradiation ◽  
Stable Conformation ◽  
Spin Resonance ◽  
Radiation Processes ◽  
Disodium Succinate

Crystals of disodium succinate have two distinct modifications, monoclinic and triclinic. These were recognized by electron spin resonance (e.s.r.) studies of. the free radicals produced by γ-irradiation. In the monoclinic crystals, e.s.r. spectra and radiation processes appear similar to those observed in γ- (or x-) irradiated succinic acid. The situation in triclinic crystals is more complex (see Part 2). In monoclinic crystals irradiated at 77 °K, two types of radical coexist. They were identified as −O2CCH2CH2ĊO22−, 1, together with a distorted conformation of the radical −O2C(ĊHCH2)*CO2−, 2. On warming to room temperature the former species disappears while the latter changes irreversibly to a stable conformation −O2CĊHCH2CO2−, 3.

Free radicals in γ-irradiated disodium succinate. Part 2. Triclinic crystals

1970 ◽  
Vol 48 (18) ◽  
pp. 2809-2813 ◽  
Author(s):  
M. Fujimoto ◽  
W. A. Seddon
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Stable Conformation ◽  
Spin Resonance ◽  
Radiation Processes ◽  
Disodium Succinate

Electron spin resonance (e.s.r.) spectra and radiation processes in γ-irradiated triclinic crystals of disodium succinate are more complex than those observed in monoclinic crystals. At 77°K, three species coexist, −O2CCH2CH2ĊO22− (1), a distorted conformation of the radical −O2C(ĊHCH2)*CO2−(2), and an unidentified radical X. On warming to room temperature, 1 and X disappear, while 2 changes to a more stable conformation −O2CĊHCH2CO2− (3). In addition the species CO2− (4), and −O2CĊHCH3 (5) are produced. On further warming to 40 °C, species 4 disappears while at the same time species 3 increases in intensity. Radical 5 remains unaffected. Possible mechanism and comparisons with monoclinic crystals are discussed.

scholarly journals The Decay of Irradiation Defects in Polymethyl Methacrylate

1962 ◽  
Vol 15 (4) ◽  
pp. 652 ◽  
Author(s):  
ID Campbell ◽  
FD Looney
Keyword(s):  
Electron Spin Resonance ◽  
Polymethyl Methacrylate ◽  
Electron Spin ◽  
Room Temperature ◽  
Γ Irradiation ◽  
Radical Species ◽  
Decay Mechanism ◽  
Spin Resonance ◽  
Chemical Groups

The decay of defects in polymethyl methacrylate caused by γ-irradiation has been followed by electron-spin resonance. The samples were irradiated at room temperature and annealed at 80, 90, and 100 �C. Two radical species can be recognized by their different modes of decay. Some attempt is made to identify the chemical groups involved and to explain the decay mechanism.

Electron spin resonance observations on trapped electrons and free radicals formed in olefins at 77 °K by γ-irradiation

1967 ◽  
Vol 45 (8) ◽  
pp. 833-837 ◽  
Author(s):  
D. R. Smith ◽  
F. Okenka ◽  
J. J. Pieroni
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Hydrogen Abstraction ◽  
Γ Irradiation ◽  
Trapped Electrons ◽  
Spin Resonance ◽  
The Matrix ◽  
Subsequent Exposure ◽  
Branched Chain

Electron spin resonance (e.s.r.) methods have been used to search for the γ-ray-induced formation of trapped electrons and free radicals in 13 straight-chain and branched-chain terminal olefins at 77 °K. When e.s.r. spectra were observed they were used to identify the species present. Changes induced by subsequent exposure to visible and ultraviolet (u.v.) light were investigated. Trapped electrons were observed in three olefins that exist as glasses at 77 °K, hexene-1, hexene-2, and 2-methylbutene-1, but were not detected in two other glassy olefins, possibly because of rapid annealing. No trapped electrons were found in polycrystalline olefins at 77 °K. The possibility that CO2− ions have been misinterpreted as trapped electrons in these and other systems is discussed and eliminated. The formation and behavior of free radicals and trapped electrons in irradiated 2-methylbutene-1 are analogous to those previously reported for 2-methylpentene-1 under similar conditions. These observations support the hypothesis that in these two systems ions produced initially isomerize rapidly, leading to the formation of the free radicals detected by e.s.r. The results of a subsidiary experiment suggest that hydrogen abstraction from the matrix is induced by u.v. photolysis of the radicals present in 2-methylpentene-1.

scholarly journals Force detection of high-frequency electron spin resonance near room temperature using high-power millimeter-wave source gyrotron

2021 ◽  
Vol 118 (2) ◽  
pp. 022407
Author(s):  
Hideyuki Takahashi ◽  
Yuya Ishikawa ◽  
Tsubasa Okamoto ◽  
Daiki Hachiya ◽  
Kazuki Dono ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Millimeter Wave ◽  
Electron Spin ◽  
High Power ◽  
High Frequency ◽  
Room Temperature ◽  
Force Detection ◽  
Wave Source ◽  
Spin Resonance ◽  
Millimeter Wave Source

scholarly journals Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy

2011 ◽  
Vol 2011 ◽  
pp. 1-11
Author(s):  
Shinobu Ito ◽  
Tomohisa Mori ◽  
Hideko Kanazawa ◽  
Toshiko Sawaguchi
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Spin Trap ◽  
Detection Sensitivity ◽  
Mouse Tissue ◽  
Spin Adduct ◽  
Simple Method ◽  
Oxidation Stress ◽  
Spin Resonance

Electron spin resonance (ESR) method is a simple method for detecting various free radicals simultaneously and directly. However, ESR spin trap method is unsuited to analyze weak ESR signals in organs because of water-induced dielectric loss (WIDL). To minimize WIDL occurring in biotissues and to improve detection sensitivity to free radicals in tissues, ESR cuvette was modified and used with 5,5-dimethtyl-1-pyrroline N-oxide (DMPO). The tissue samples were mouse brain, hart, lung, liver, kidney, pancreas, muscle, skin, and whole blood, where various ESR spin adduct signals including DMPO-ascorbyl radical (AsA∗), DMPO-superoxide anion radical (OOH), and DMPO-hydrogen radical (H) signal were detected. Postmortem changes in DMPO-AsA∗and DMPO-OOH were observed in various tissues of mouse. The signal peak of spin adduct was monitored until the 205th day postmortem. DMPO-AsA∗in liver (y=113.8–40.7 log (day),R1=-0.779,R2=0.6,P<.001) was found to linearly decrease with the logarithm of postmortem duration days. Therefore, DMPO-AsA∗signal may be suitable for detecting an oxidation stress tracer from tissue in comparison with other spin adduct signal on ESR spin trap method.

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