• Korean Journal of Plant Resources
• /
• v.22 no.5
• /
• pp.461-466
• /
• 2009

This study was carried out to evaluate the effects of yam (Dioscorea batatas Dence) extracts on the cell viability, growth and nucleus-DNA damage of tobacco cells which were exposed to $\gamma$-radiation stress. The viability and growth of tobacco cells exposed to 20 Gy of radiation stress were effectively recovered by pretreatment of 10 mg/L ethylacetate (EtOAc) yam extract. Pretreatment of EtOAc extract showed 20% higher cell viability and fresh weight growth than that of cells without pretreatment in 20 Gy radiation treated tobacco cells. Nucleus-DNA damage was measured as the ratio of tail length (T) to head length (H) in individual comet image isolated from tobacco cells. The T/H ratio of control-cells and treated-cells at 20 Gy were 1.05 and 1.68, and % head DNA of those cell were 86.7 and 71.3%, respectively, suggesting that nuclei of tobacco cells were severely damaged in the integrity of DNA by the treatment of $\gamma$-radiation. However, pretreatment of MeOH, EtOAc and n-BuOH extracts decreased radiation induced DNA-damage in the tobacco cells, showing T/H ratio of 1.37, 1.01 and 1.10 and % head DNA of 81.5, 87.6 and 88.7%, respectively.

• Korean Journal of Environmental Biology
• /
• v.28 no.4
• /
• pp.212-217
• /
• 2010

Soil pollution by heavy metals has become a significant environmental concern due to a variety of human activities. Specially toxicity caused by excessive mercury exposure is now being recognized as a widespread environmental problem and is continuing to attract a great deal of public concerns. The earthworms are very important animals that aerate the soil with their burrowing action and enrich the soil by decomposing organic matters. Especially the earthworm Eisenia fetida is routinely used in ecotoxicological studies. The levels of DNA damage in earthworms treated with HgCl2 and ionizing radiation were investigated in this study. Genotoxic effects were evaluated in the earthworm's coelomocytes using the comet assay (Single Cell Gel Electrophoresis; SCGE). The results showed that the mercury chloride and radiation were responsible for the genotoxic effects on earthworms. The level of DNA damage significantly increased after the treatment of mercury chloride combined with ionizing radiation. The combined treatment of $HgCl_2$ and ionizing radiation had a greater genotoxicity. This study is amenable to further study such as enzyme activation assay.

• Korean Journal of Plant Resources
• /
• v.29 no.1
• /
• pp.128-135
• /
• 2016

This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD₅₀) was approximately 392 Gy. The median reduction dose (RD₅₀) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M₂ generation decreased as the dose increased over 400 Gy.

• 대한방사선방어학회:학술대회논문집
• /
• 2011.11a
• /
• pp.292-293
• /
• 2011

• Journal of radiological science and technology
• /
• v.43 no.1
• /
• pp.29-34
• /
• 2020

Mitochondria was observed much around the nuclear membrane of liver tissue where the energy metabolism process is active. Testis tissue had a large number of undifferentiated cells, and cristae in Inner membrane of Mitochondria was not observed clearly. Morphological damage occurred first in Inner membrane rather than the outer membrane. The kidney tissue was clearly observed in the form of cristae. Radiation-induced damage occurred at the edges of both ends, and the membrane was observed bursting with the thickness of the outer membrane. Small intestine cells were observed in many mitochondria in the tissues around the villus, where bowel movements were active. Morphological damage occurred with the outer and inner membranes getting tangled. Mitochondria sensitivity to radiation was sensitized in testis and small intestine tissues, and kidney, ovary and liver tissues were found to be resistant.

• Nuclear Engineering and Technology
• /
• v.45 no.3
• /
• pp.311-322
• /
• 2013

High-Cr martensitic steel HT-9 is one of the candidate materials for advanced nuclear energy systems. Thanks to its excellent thermal conductivity and irradiation resistance, ferritic/martensitic steels such as HT-9 are considered for in-core applications of advanced nuclear reactors. The harsh neutron irradiation environments at the reactor core region pose a unique challenge for structural and cladding materials. Microstructural and microchemical changes resulting from displacement damage are anticipated for structural materials after prolonged neutron exposure. Consequently, various irradiation effects on the service performance of in-core materials need to be understood. In this work, the fundamentals of radiation damage and irradiation effects of the HT-9 martensitic steel are reviewed. The objective of this paper is to provide a background introduction of displacement damage, microstructural evolution, and subsequent effects on mechanical properties of the HT-9 martensitic steel under neutron irradiations. Mechanical test results of the irradiated HT-9 steel obtained from previous fast reactor and fusion programs are summarized along with the information of irradiated microstructure. This review can serve as a starting point for additional investigations on the in-core applications of ferritic/martensitic steels in advanced nuclear reactors.

• Journal of Radiation Protection and Research
• /
• v.13 no.1
• /
• pp.1-7
• /
• 1988

A bubble-damage polymer detector, which operation principles are based on vaporization of superheated liquid drops by interaction with radiations, is developed for neutron dosimetry. The detectors are fabricated by dispersing the superheated liquid drops of Freon12 into transparent and elastic polymer made of acylamide and glycerine. The bubbles formed by neutron irradiation are immediately visible. The neutron sensitivity of the detectors is 4-7 bubbles/10$\mu$ Sv for Am-Be neutrons.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.279.2-280
• /
• 2002

Ascorbic acid is very well known as one of various ntioxidants and is used very popular in man. Melatonin. an endogenous compound secreted by the pineal gland in human brain has been reported to act as an antioxidant nowadays. The present study was performed to obtain the differences of the radioprotective function of ascorbic acid and combination with melatonin according to the administration dose a day on radiation induced DNA damage in mouse spleen and blood. (omitted)

• Korean Journal of Digital Imaging in Medicine
• /
• v.7 no.1
• /
• pp.39-44
• /
• 2005

Purpose of this research is that if Radiographer has focused on Radiation exposure research until now, he should realize that always exposed by Electro Magnetic Wave at given working environment And also, another purpose is that to minimize damage with measuring Electro Magnetic Wave which is happened area and distance of Radiation Control System and High Voltage Equipment, check occurrence rate and minimize damage from it.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.3
• /
• pp.524-528
• /
• 2001

The measurement of radiation response using simple and informative techniques would be of great value in studying the genetic risk following occupational, therapeutic, or accidental exposure to radiation. When patients receive radiation therapy, many suffer from side effects. Since each patient receives a different dose due to different physical conditions, it is important to measure the exact dose of radiation received by each patient to lessen the side effects. Even though several biological dosimetric systems have already been developed, there is no ideal system that can satisfy all the criteria for an idean dosimetric system, especially for low-dose radiation as used in radiation therapy. In this study, an SOS Chromotest of E. coli PQ37 was evaluated as a novel dosimeter for low-dose gamma-rays. E. coli PQ37 was originally developed to screen chemical mutagens using the SOS Chromotest-a colorimtric assay, based on the induction of ${\beta}$-galactosidase ue to DNA damage. The survival fraction of E. coli PQ37 decreased dose-dependently with an increasing dose of cobalt-60 gamma-rays. Also, a good linear correlation was found between the biological damage revealed by the ${\beta}$-galactosidase expression and the doses of gamma-rays. The expression of ${\beta}$-galactosidase activity that responded to low-dose radiation under 1 Gy was $Y=0.404+(0.089{\pm}0.3)D+(-0.018{\pm}0.16)D^2$ (Y, absorbance at 420 nm; D, Dose of irradiation) as calculated using Graph Pad In Plot and Excel. When a rabbit was fed with capsules containing an agar block embdded with E. coli PQ37 showed a linear response to the radiation doses. Accordingly, the results confirm that E. coli PQ37 can be used as a sensitive biological dosimeter fro cobalt-60 gamma-rays. To the best of our knowledge, this is the first time that a bacterium has been used as a biological dosimeter, especially for low-dose radiation.