| Project/Area Number |
18510051
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Risk sciences of radiation/Chemicals
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
HIROSHI Murakami Japan Atomic Energy Agency, Advanced Photon Research Center, Research Scientist (50291092)
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| Co-Investigator(Kenkyū-buntansha) |
AKAMATSU Ken Japan Atomic Energy Agency, Division of Environment and Radiation, Research Scientist (70360401)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,530,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥330,000)
Fiscal Year 2007: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2006: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | DNA / damage due to ultraviolet radiation / two photon absorption / ultrafast spectroscopy / 鎖切断 |
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| Research Abstract |
1. Development of transient absorption spectroscopy measurement system : We have programmed for control of a spectrometer with a multi-channel detector, mechanical shutters, optical delay line, and movable stage positioning a sample. Further we have attained a temporal resolution of about 200 fs by optimizing the optical alignment. Thus we have almost completed the development of the measurement system for molecular-level and femtosecond time-resolved observation of DNA after UV pulse irradiation.
2. Preparation of DNA film and examination of radiation damage : We prepared pUC18 plasmid DNA using a plasmid DNA purification kit with Bacillus coli, casted the DNA aqueous solution onto a quartz glass plate, and made a dried film under Ar atmosphere. Damaged DNA was examined by an agarose gel electrophoresis.
3. Measurement of how features of damaged DNA depend on the intensity and total photon number of the irradiated UV (266nm) pulse: We have made the measurement under the light intensity from a few ten MW/cm^2 to several ten GW/cm^2. It has been found that single-strand broken DNA, double-strand broken DNA, and DNA dimer generate, and that the amount of them increases with increasing the total photon number. On the other hand, the double-strand broken DNA appears above the threshold of a few GW/cm^2, and the amount of it increases with increasing the intensity. This suggests that the ionization due to the two-photon absorption of the UV pulse induces the double-strand break. Real-time probe of the intensity of the UV pulse, which fluctuates with time, has been accomplished, which allows us to get higher signal to noise ratio of the data.
The future plan is as follows : 1) Analysis on dependence of the feature of damaged DNA on the intensity and total photon number of the irradiated light ; 2) femtosecond transient absorption spectroscopy of DNA.
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