• 방사선산업학회지
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• 제6권2호
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• pp.165-169
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• 2012

This study was conducted to determine the prevention effect of poly-gamma-glutamic acid (${\gamma}-PGA$) on tissue damage induced by gamma irradiation for development of xenograft. Porcine tendons were treated at various doses of ${\gamma}-PGA$ (0.1, 0.5, 1 and 5%) and then gamma-irradiated (30 kGy). Prevention effects on tissue damage were measured as the result of tensile strength, hydroxyproline contents and viscosity of ${\gamma}-PGA$. Tensile strength was remarkably decrease in gamma-irradiated porcine ligament, but increased by ${\gamma}-PGA$ treated one. Among the ${\gamma}-PGA$ treatment doses, 1% treated group showed the highest values of tensile strength compared to non-treated group. Hydroxyproline contents was significantly increased by gamma irradiation, but decreased by the ${\gamma}-PGA$ treatment. Particularly, 1 and 5% ${\gamma}-PGA$ treated group were exhibited lower values of hydroxyproline contents than other group. In the result of viscosity, gamma-irradiated ${\gamma}-PGA$ (1%) was remarkably increased. Base on the results, it demonstrated that gamma irradiation induces severe alteration of mechanical property and collagen contents on porcine ligament, but ${\gamma}-PGA$ can effectively prevent these tissue damage.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1305-1309
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• 2009

This study evaluated the effects of $\gamma$-irradiation on immunomodulating properties and structural changes of ${\beta}$-glucan. ${\beta}$-Glucan solutions (10 mg/mL) were ${\gamma}$-irradiated at 10, 30, and 50 kGy. Splenocyte proliferation and cytokine (interferon-${\gamma}$ and interlukin-2) productions by ${\gamma}$-irradiated ${\beta}$-glucan were evaluated in in vivo and in vitro, and structural changes of ${\beta}$-glucan were also determined after ${\gamma}$-irradiation. ${\gamma}$-Irradiation on ${\beta}$-glucan at 50 kGy enhanced splenocyte proliferation and cytokine productions, (p<0.05) and cleft glycosidic bonds of ${\beta}$-glucan resulting in lower the molecular weight. These results indicate that the use of ${\gamma}$-irradiation on ${\beta}$-glucan may be useful for improving its immunological activity by lowering the molecular weight of ${\beta}$-glucan.

• Journal of Microbiology and Biotechnology
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• 제28권4호
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• pp.527-533
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• 2018

This study compared the radioprotective effects of high-molecular-weight poly-gamma-glutamate (${\gamma}-PGA$, average molecular mass 3,000 kDa) and a reduced form of glutathione (GSH, a known radioprotector) on calf thymus DNA damage. The radiation-induced DNA damage was measured on the basis of the decreased fluorescence intensity after binding the DNA with ethidium bromide. All the experiments used $^{60}Co$ gamma radiation at 1,252 Gy, representing 50% DNA damage. When increasing the concentration of ${\gamma}-PGA$ from 0.33 to $1.65{\mu}M$, the DNA protection from radiation-induced damage also increased, with a maximum of 87% protection. Meanwhile, the maximal DNA protection when increasing the concentration of GSH was only 70%. Therefore, ${\gamma}-PGA$ exhibited significant radioprotective effects against gamma irradiation.

• Journal of Radiation Protection and Research
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• 제42권2호
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• pp.91-97
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• 2017

Background: A gamma energy identifying algorithm using spectral decomposition combined with smoothing method was suggested to confirm the existence of the artificial radio isotopes. The algorithm is composed by original pattern recognition method and smoothing method to enhance the performance to identify gamma energy of radiation sensors that have low energy resolution. Materials and Methods: The gamma energy identifying algorithm for the compact radiation sensor is a three-step of refinement process. Firstly, the magnitude set is calculated by the original spectral decomposition. Secondly, the magnitude of modeling error in the magnitude set is reduced by the smoothing method. Thirdly, the expected gamma energy is finally decided based on the enhanced magnitude set as a result of the spectral decomposition with the smoothing method. The algorithm was optimized for the designed radiation sensor composed of a CsI (Tl) scintillator and a silicon pin diode. Results and Discussion: The two performance parameters used to estimate the algorithm are the accuracy of expected gamma energy and the number of repeated calculations. The original gamma energy was accurately identified with the single energy of gamma radiation by adapting this modeling error reduction method. Also the average error decreased by half with the multi energies of gamma radiation in comparison to the original spectral decomposition. In addition, the number of repeated calculations also decreased by half even in low fluence conditions under $10^4$ ($/0.09cm^2$ of the scintillator surface). Conclusion: Through the development of this algorithm, we have confirmed the possibility of developing a product that can identify artificial radionuclides nearby using inexpensive radiation sensors that are easy to use by the public. Therefore, it can contribute to reduce the anxiety of the public exposure by determining the presence of artificial radionuclides in the vicinity.

• 방사선산업학회지
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• 제7권2_3호
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• pp.155-159
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• 2013

Late effects of chronic exposure to gamma radiation are potential hazards to worker in radiation facilities as well as to the general public. Recently, chronic gamma radiation exposure effects have become a serious concern. Using a total of 60 mice, we studied the biological effects of medium-dose chronic exposure to gamma radiation. Sixty female 6-week-old specific pathogen free Balb/c mice were randomly divided into six groups (five groups irradiated and one non-irradiated control group). Irradiation was carried out for 7 days using gamma rays at dose rates of 119.65, 238.10, 357.14, 476.19 and $595.24mGy\;h^{-1}$ with total doses 20, 40, 60, 80 and 100 Gy. After irradiation, we determined survival rate of gamma radiation exposed mice during 1 week and 476.19 and $595.24mGy\;h^{-1}$ exposed group mice showed less 10% of survival rate. Otherwise, 119.65, 238.10 and $357.14mGy\;h^{-1}$ exposed group mice were survived each 100%, 80% and 70%. Half of survived mice after 1 week are immediately sacrifice and counted body and spleen weights. Compared with control non-irradiated group, total body weights and spleen weights isolated from 119.65, 238.10 and 357.14 irradiated group mice showed significant decreased. However, no significant alteration was observed between 119.65, 238.10 and $357.14mGy\;h^{-1}$ irradiated group. Overall, our results show for the first time that medium-dose chronic gamma radiation has the potential to stimulation of biological effects.

• 방사선산업학회지
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• 제7권1호
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• pp.55-59
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• 2013

Ionizing radiation causes the massive generation of reactive oxygen species, resulting in cellular and tissue damage. The present study was performed to evaluate ${\gamma}$-irradiation induced cellular damage in ICR mice. The mice were divided into four groups with ten mice in each group. Group 1 served as an unexposed control group. Groups 2, 3, and 4 were exposed to 3, 5, and 7 Gy of ${\gamma}$-radiation, respectively. Five mice per group were sacrificed 1 and 7 days after ${\gamma}$-radiation. Exposure to ${\gamma}$-irradiation resulted in hematopoietic damage in a dose-dependent manner when compared with the unexposed control group, which featured a significantly decreased spleen index. However, the exposed mice showed no significant differences in their serum AST, ALT and in the histopathological change of their liver. These results suggest that ${\gamma}$-irradiation is a good tool to prepare a hematopoietic damage model. This animal model can be employed to study the hematopoietic efficacy of biologically active compounds.

• 방사선산업학회지
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• 제5권1호
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• pp.63-67
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• 2011

A comparative experiment was conducted to compare the effects of persulfate with gamma radiation on the disinfection efficiencies against Escherichia coli K12. The microorganism used for the disinfection experiments were prepared by transferring a bacterial stock culture into a 50 ml nutrient broth an incubating for 24 hrs at $37^{\circ}C$. The initial concentration of the harvested culture was approximately $10^7$ to $10^9CFU\;ml^{-1}$. The culture solution was irradiated at different absorbed doses of 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, and 1 kGy, respectively. The disinfection efficiency of persulfate with gamma radiation of 0.3 kGy against Escherichia coli K12 was 97.2% and while the gamma radiation only was 90.01% at 0.3 kGy. Therefore, it could be thought that addition of persulfate in the disinfection of Escherichia coli K12 can enhance the disinfection efficiency when it is used together with gamma radiation.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1634-1641
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• 2021

Exposure to gamma-rays is hazardous for humans and other living beings because of their high penetration through the materials. For this reason, shielding materials (usually lead, copper and stainless steel) are used to protect against gamma rays. This study's objective was to prepare ceramic materials for gamma radiation shielding by using different natural bentonite clays. Gamma-ray attenuation performances of the prepared shielding materials at different thicknesses were investigated and evaluated for different gamma-ray energies from different standard point gamma radiation sources (²⁵¹Am, ⁵⁷Co, ¹³⁷Cs, ⁶⁰Co, and ⁸⁸Y). The mass and linear attenuation coefficients of the prepared ceramics vary between 0.238 and 0.443 cm² g^-1 and between 0.479 and 1.06 cm^-1, respectively, depending on their thicknesses. Results showed that these materials could be prioritized because of their evidential properties of gamma radiation protection in radiation applications.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2151-2161
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• 2020

The study presents a review of research advancements in the field of gamma radiation detection systems for emergency radiation monitoring, particularly two major sub-systems namely (i) the radiation detector and (ii) the detection platform - air-borne and ground-based. The dynamics and functional characteristics of modern radiation detector active materials are summarized and discussed. The capabilities of both ground-based and aerial vehicle platforms employed in gamma radiation monitoring are deliberated in depth.

• 환경생물
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• 제18권2호
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• pp.247-253
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• 2000

저선량 ${\gamma}$선이 시판중인 배추 신규종자인 "만점" 배추와 묵은 종자인 "서림엇갈이" 배추의 발아와 초기생육 및 생리활성에 미치는 영향을 조사하였다. 배추종자의 발아와 초기생육에 있어 신규종자에서는 별효과가 없었으나 묵은 종자에서는 촉진효과가 있었고 그 적정 선량은 1.0Gy와 2.0Gy였다. 배추유식물체의 엽록소 함량은 저선량 조사구가 대조구보다 높았으며 조사선량의 증가에 따라 대체로 증가하였고, 저선량 조사에 의한 배추유식물체의 항산화효소 활성은 증가하였으나 낮은 선량에서 증가하였고 높은 선량에서는 감소하였다.가하였고 높은 선량에서는 감소하였다.