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  • 28 September 2000 Volume 9 Issue 3
      
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  • 210Po in cigarette and the radiation dose inhaled by smoker
    WANG Xin, CHEN Xing-an, PAN Ying-dong
    2000, 9(3): 129-133.
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    The contents of Poionium-210 in 16 brands of cigarettes from China and 4 brands of cigarettes from abroad were reported.The method we used for separating Polonium-210 was electrochemical deposition method.The 210Po contents were analy zed in whole cigarettes from freshly opened packs.The 210Po contents of the China-made cigarettes ranged from 13.7 to 43.4 mBq/cig, from 18.0 to 67.3 mBq/g respectivily, the mean values were 26.5 mBq/cig and 33.7 mBq/g respectively.The content of 210Po in cigarettes from China is higher than that from abroad.
    The polonium contents of the ash, butt and main stream smoke were reported.The cigarettes were smoked with the eight-channel smoking machine for determining the concentration of the radionuclides in main stream smoke.("Main Stream" means smoke taken into the mouth).About 15% of 210Po contained in a cigarette was transferred into the main stream smoke, 40% of the whole 210Po content remained in the ash and butt for filter cigarette, 60% for nonfilter.
    The daily intake of the 210Po from cigarette was 80mBq, the annual dose equivalent to the lung tissue of human body was 0.46 mSv.In view of present knowledge, it is improbable that this dose is significant for the higher incidence of lung cancer in smokers.
  • Determination of the Radiation dose of video display terminals with LiF(Mg, Cu, P) thermoluminescent dosimeter
    YUAN shu-yu, SUN fu-yin
    2000, 9(3): 134-136.
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    Objective The measurement of low energy x ray dose emitted by video display terminals.Method Thermoluminescent dosimetry (TLD) has been used to determinate the radiation dose of the video display terminals (VDT) and the exposure in extra of radiation protection screen.Results The average exposure in VDT surface is 2.40×10-7C·kg-1/d (0.93mR/d).The exposure in extra of radiation protection screen is 0.62×10-7C·kg-1/d (0.24mR/d).Conclusion The measurement results show that the low-level and low energy ionizing radiation doses produced by VDT are not beyond the related regulations.
  • Relateness of radioresistance and nuclear DNA-binding protein in deinococcus radiodurans
    WANG Ming-suo, DU Ze-ji, YANG Zhan-shan, et al
    2000, 9(3): 137-138.
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    The exploration of the role of DNA-binding proteins (DBPs) from a radioresistant bacterium i.e.Deinococcus radiodurans(D.radiodurans).The DBPs from three wild type of D.radiodurans i.e.MR1, KR1 and Sark were determined by south-western bloting using the chromosomal DNA labeled with digoxin as a probe, and the N-terminal AA sequence of some DBPs was analysed.Results showed that there are 8 kinds of characterictic DBPs in the wild types of radioresistent bacterium whose molecular weights were 122, 93, 33, 29, 16, 15, 14and 12 kDa, among whom, the DBPs of 93 and 33kDa from wild type of KR1 were found to be novel proteins by the AA Sequence analysis.The expression levels of the two DBPs change with different culture media at different culture time.It was suggested that the DBPs, especially the DBPs of 93 and 33 kDa, were closely related to the radioresistance of D.radiodurans.
  • Surveillance of Radioactive Level in Habitation and Study of Superlimit Coutrol
    JIA Cheng-tie, CHENGJun-liang, ZHANG Shu-rong, et al
    2000, 9(3): 139-140.
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    Objective: To study effective techniques of controlling high-radioactive of habitation that caused by some building material, so to improve indoor health quality.Method: By studying the radioactive level of building material in buildings, we used new techniques to reduce radioactive level of building material and radom density.Result: The γ-radio-rate and radom density of building material which before control was 76.8×10-8Gy·h-1 and 235.02 Bq·m-3 reduced by 64.9% and 70%, both required GB-6566-86, The radom density in buildings of 243.56 Bq·m-3 was decreased to 51.15 Bq·m-3(<100 Bq·m-3).These show large improvement of indoor health quality.Conclusiou: High-radioactive mainly origined from superlimit building material.So more surveillance and effective prevention are main importaut measures to improve radioactive quility indoor.