• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.189-195
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• 2007

To study the protective effects of antioxidants on the radiation damages of the cells, vascular smooth muscle cells(VSMC) from thoracic aorta of Sprague-Dawley rats were cultured and irradiated with gamma-ray. Cell viability was measured by direct cell counting and MTT assay, and flow cytometry was performed to measure fractional distributions of the cells. Gamma-ray irradiation inhibited cell proliferations accompanied with decreased G1 phase and increased S- and G2/M phases, and the maximum effects were observed at 1500 or 2000 cGy. Submaximal concentrations of antioxidants, such as allopurinol, vitamin C, N-acetylcycteine(NAC), lipoic acid, dihydrolipoic acid and rebamipide tended to increase the cell viability suppressed by low dose of radiation(500 cGy), and enalapril and vitamin E increased it significantly. Allopurinol, vitamin E, NAC, lipoic acid, captopril and enalapril significantly increased G1 phase. Allopurinol and vitamin E tended to increase c-Myc expression, detected by Western blot, that was reduced by the radiation, and enalapril increased it significantly. The cell viability and c-Myc expression were highly correlated(r=0.97) with each other. These results suggest that antioxidants, especially enalapril and vitamin E, recover the viability of VSMC from gamma-radiation injury, through a mechanism which includes increase of c-Myc protein expression.

• Journal of Radiation Protection and Research
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• v.34 no.4
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• pp.170-175
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• 2009

For the emergency radiation monitoring using gamma spectrometry, we should sufficiently survey the background spectra as environmental samples with systematic nuclide identification method. In this study, we obtained the gamma ray energy spectrum using a HPGe gamma spectrometry system from an air sample. And we identified nuclide of the gamma ray energy peaks in the spectrum using two methods -1) Half life calculation and 2) survey for cascade coincidence summing peaks using nuclear data. As the results, we produced the nuclide identification results for the air sample.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1045-1051
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• 2023

In this study, we fabricated a liquid light-guide-based radiation sensor with a LaBr₃:Ce scintillator for remote gamma-ray spectroscopy. We acquired the energy spectra of Cs-137 and Co-60 using the proposed sensor, estimated the energy resolutions of the full energy peaks, and compared the scintillation light output variations. The major peaks of the radionuclides were observed in each result, and the estimated energy resolutions were similar to that of a general NaI(Tl) scintillation detector without a liquid light guide. Moreover, we showed the relationships of energy resolution and analog-to-digital channel regarding the number of photoelectrons produced and confirmed the effects of light guide length on remote gamma-ray spectroscopy. The proposed sensor is expected to be utilized to perform remote gamma-ray spectroscopy for distances of 3 m or more and would find application in many fields of nuclear facilities and industry.

• Journal of Radiation Protection and Research
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• v.24 no.3
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• pp.123-129
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• 1999

Tomato (Lycopericum esculentum $M_{ILL}$ cv. Seokwang and cv. Housemomotaro) seeds were irradiated with the doses of $1{\sim}20$ Gy from $^{60}Co$ $\gamma$-ray source to investigate the effect of the low dose $\gamma$-ray radiation on the early growth and resistance to subsequent high dose of radiation. Germination rate of seeds irradiated with low dose $\gamma$-ray was enhanced in Seokwang cultivar but not in Housemomotaro cultivar. Seedling height increased in 4 Gy and 8 Gy irradiation group of both cultivars. Plant height of Seokwang cultivar was depressed in low dose irradiation group but fresh weight was increased in 2 Gy and 4 Gy irradiation group. In Housemomotaro cultivar, plant height increased in 12 Gy and 20 Gy irradiation group and fresh weight increased in 4 Gy and 20 Gy irradiation group. Growth inhibition of tomato plants by high dose radiation was noticeably reduced by pre-irradiation of low dose radiation. Resistance to subsequent high dose of radiation was enhanced in 2 Gy and 8 Gy Irradiation group of Seokwang cultivar and in 2 Gy and 12 Gy irradiation group of Housemomotaro cultivar.

• Journal of Radiation Industry
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• v.8 no.2
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• pp.89-95
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• 2014

This study was conducted to determine the optimal dose of gamma-ray on the growth and nucleus DNA damage for mutation breeding in licorice. Gamma-rays irradiated to dry seeds with various doses (0 to 1000 Gy). Significant decreases in germination rate (%), survival rate (%) and growth characteristics (plant height, number of leaves, root length and fresh weight) were observed by dose of increased. $LD_{50}$ (lethal dose) was approximately 400 Gy to 500 Gy. Also, reduction doses ($RD_{50}$) of plant height, number of leaves, root length and flash weight were 428 Gy, 760 Gy, 363 Gy and 334 Gy, respectively. It is supplest that the optimal dose of gamma irradiation for licorice mutation induction might be about 400 Gy in this study. We also conducted comet assay to observe nucleus DNA damage due to gamma irradiation. In comet assay, a clear difference was identified over 300 Gy treatments. With increasing doses of gamma-ray in the range of 100 to 1000 Gy, the rate of head DNA was decreased significantly from 92.88% to 73.09%. Tail length(${\mu}m$) was increased as the dose of increased over 300 Gy. Growth characteristics (Germination rate, Survival rate, plant height, number of leaves, root length and fresh weight) were highly negatively ($P{\leq}0.01$) correlated with dose. While the tail length was highly positively ($P{\leq}0.01$) correlated with dose.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.368-370
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• 1998

In order to determine the optimal radiation dose for the sterilization of biowastes, the bioburden, frequencies and radiosensitivities of bacteria, mold and fungi in rice straw, chaff, corn stover and sawdust was observed before and after ${\gamma}-ray$ irradiation. Radiation sterilization dose of rice straw, chaff, com stover and sawdust was calculated as 17.7, 17.6, 15.6 and 20.0kGy, respectively, from the mutual compensation of screening dose and derived dose on the basis of $10^{-3}$ SAL. This method could be acceptable for the sterilization of various biowastes including food, pharmaceuticals, etc.

• Journal of radiological science and technology
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• v.24 no.1
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• pp.49-53
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• 2001

A number of radionuclides of interest in nuclear medicine are short lived isotopes that emit only gamma ray. The most of all Dept. of Nuclear Medicine in the hospt. are using the $^{99}Mo-^{99m}Tc$ generator for elution of the short lived isotope $^{99m}TcO_4$. A $^{99}Mo-^{99m}Tc$ generator consists of an alumina column on which $^{99}Mo$ is bound. The parent isotope($^{99}Mo$ : half life 67 hr.) decays to its daughter $^{99m}TcO_4^-$ which is a different element with a shorter half-life. $^{99}Mo$ emitted 41-keV(1.3%), 141-keV(5.6%) 181-keV(6.6%) and 366-keV(1.5%) gamma rays. But $^{99m}TcO_4$ emitted only 140-keV gamma ray. We study about the gamma ray distribution around the $^{99}Mo$ generator. And obtained the result as follows ; 1. Total counted gamma ray from generator smaller in front side than back. 2. The gamma ray emitted from $^{99}Mo$ generator without $^{99m}TcO_4$ vial increased in the back side(Mo column posited side) 3. The gamma ray only from the $^{99m}TcO_4$ vial increased in the front side. 4. Apron can protect gamma ray above 60% of total radiation from the $^{99}Mo$ generator.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.2
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• pp.129-137
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• 2024

To non-destructively determine the burnup of a spent nuclear fuel assembly, it is essential to analyze the nuclear isotopes present in the assembly and detect the neutrons and gamma rays emitted from these isotopes. Specifically, gamma-ray measurement methods can utilize a single radiation measurement value of ¹³⁷Cs or measure based on the energy peak ratio of Cs isotopes such as ¹³⁴Cs/¹³⁷Cs and ¹⁵⁴Eu/¹³⁷Cs. In this study, we validated the extent to which the results of gamma-ray measurements using cadmium zinc telluride (CZT) sensors based on ¹³⁷Cs could be accurately simulated by implementing identical conditions on MCNP. To simulate measurement scenarios using a lead collimator, we propose equations that represent radiation behavior that reaches the detector by assuming "Direct hit" and "Penetration with attenuation" situations. The results obtained from MCNP confirmed an increase in measurement efficiency by 0.47 times when using the CZT detector, demonstrating the efficacy of the measurement system.

• Archives of Pharmacal Research
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• v.18 no.6
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• pp.410-414
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• 1995

Adaptive response induced by low dese .gamma.-ray irradiation in human cervical carcinoma cells was examined. Cells were exposured to low dose of .gamma.-ray irradiation in human cervical carcinoma cells was examined. Cells were exposured to low dose of .gamma.-ray (1-cGy) followed by high doses of r-ray irradiation (0,1,2,3,5,7 and 9Gy for chlnogenic assay or 1.5Gy for micronucleus assay) with various time intervals. Survival fractions of cells in both low dose-irradiated and unirrated groups were analyzed by clonogenic assay. Surviva fractions of low dose-irradiated in cell survival was maximum when low and high dose irradiation time interval was 4 hr. Frequencies of micronuclei which is an indicative of chromosome aberration were also enutained from survival fractions analyzed by clonogenic assay, maximum when low and high dose irradiation time interval was 4hr. Frequencies of micronuclei which is an indicative of chromosome aberration were also enumerated in both low dose-irradiated and unirradiated groups. In consiststent with the result obtained from survival fractions analyzed by clonogenic assay, maximum reduction in frquencies of micronuclei was observed when low dose radiation was given 4 hr prior to high response to subsequent high dose .gamma.-ray irradiation in human cervical carcinomal cells. Our data suggest that one of the possible mechanisms of adaptive response induced by low dose rediation is the increase in repair of DNA double strand breaks in low dose radiation-adapted cells.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4664-4670
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• 2023

Radiation is the main safety issue for almost all nuclear applications, which must be controlled to protect living organisms and the surrounding materials. In this context, radiation shielding materials have been investigated and used in nuclear technologies. The choice of materials depends on the radiation usage area, type, and energy. Polymer materials are preferred in radiation shielding applications due to their superior characteristics such as chemical inertness, resistivity, low weight, flexibility, strength, and low cost. In the presented work, ABS polymer material, which is possibly the most commonly used material in 3D printers, is mixed with Gd₂O₃ and Er₂O₃ nanoparticles. ABS filaments containing these rare-earth elements are then produced using a filament extruder. These produced filaments are used in a 3D printer to create shielding samples. Following the production of shielding samples, SEM, EDS, and gamma-ray shielding analyses (including experiments, WinXCOM, GEANT4, and FLUKA) are performed. The results show that 3D printing technology offers significant enhancements in creating homogeneous and well-structured materials that can be effectively used in gamma-ray shielding applications.