Document Detail


EPR study of light illumination effects on radicals in gamma-irradiated L-alanine.
MedLine Citation:
PMID:  15134731     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exposure of gamma-irradiated L-alanine samples to sunlight and to light from a regular, fluorescent lamp resulted in significant changes in their EPR resonance patterns, both to spectral shapes and intensities. The experimental EPR spectra were numerically decomposed into three components reflecting contributions of three different radicals (R1-R3) generated by ionizing radiation in alanine. The light exposure caused a decay of the measured EPR signal intensity. For similar light intensities and exposure times the decay was much more pronounced in samples illuminated by sunlight than in samples illuminated by the fluorescent lamp. In both cases light-induced decay of R1 radicals was observed. Sunlight illumination resulted in a moderate decay of R2 radicals and in a doubling of the R3 radical population. On the other hand, fluorescent light caused a significant increase of R2 radicals and did not change the amount of R3 radicals. A quantitative analysis of the variations of the three radical contributions to the total EPR spectra upon fluorescent light exposure suggests a net R1-->R2 free radical transformation. These effects of light on the alanine dosimetric signal should be taken into account in dosimetry protocols, assuring protection of alanine dosimeters from extended exposure to light.
Authors:
B Ciesielski; K Schultka; M Penkowski; E Sagstuen
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy     Volume:  60     ISSN:  1386-1425     ISO Abbreviation:  Spectrochim Acta A Mol Biomol Spectrosc     Publication Date:  2004 May 
Date Detail:
Created Date:  2004-05-11     Completed Date:  2004-12-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9602533     Medline TA:  Spectrochim Acta A Mol Biomol Spectrosc     Country:  England    
Other Details:
Languages:  eng     Pagination:  1327-33     Citation Subset:  IM    
Affiliation:
Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland. bciesiel@amg.gda.pl
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MeSH Terms
Descriptor/Qualifier:
Alanine / chemistry,  radiation effects*
Dose-Response Relationship, Radiation
Electron Spin Resonance Spectroscopy*
Free Radicals / chemistry,  radiation effects*
Gamma Rays
Light*
Lighting
Microwaves
Powders
Sunlight
Temperature
Time Factors
Chemical
Reg. No./Substance:
0/Free Radicals; 0/Powders; 56-41-7/Alanine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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