Effect of ionizing radiation on the DNA damage response in Chlamydomonas reinhardtii

안준우,최윤이,구광민,정세라,김진백,김상훈,권순재,정원중,정국현,강시용 한국유전학회 2017 Genes & Genomics Vol.39 No.1

The DNA damage response (DDR) is induced by various DNA damaging factors and maintains genome stability in all organisms. The Chlamydomonas reinhardtii genome contains putative homologous genes involved in DDR; however, little is known about the functions and responses of these genes to DNA damage. In this study, DDR by gamma radiation was determined in C. reinhardtii. Irradiation with 80, and 200 Gy gamma radiation caused death in approximately 47 and 97 % of C. reinhardtii cells, respectively. The absolute lethality of cells was at 300 Gy. The rate of DNA breaks was also determined using comet assays after exposure to different doses of gamma radiation. Irradiation with 80 and 400 Gy resulted in 17 and 34 % of nuclear degradation in C. reinhardtii cells, respectively. To identify the major DDR pathway of C. reinhardtii induced by gamma radiation, 24 putative DDR genes were selected from the Joint Genome Institute (JGI) database. Gamma radiation significantly affected expression of 15 genes among these. Therefore, these genes displaying expressional changes by gamma radiation are involved in DDR, which indicate that C. reinhardtii may possess a fundamental conserved DDR pathway with higher plants. Furthermore, radiation responsive proteins were identified by proteomic analysis, which are involved in metabolisms of carbohydrate, energy, and photosynthesis. This is the first report to describe the responses of DDR homologous genes to gamma radiation and to identify gamma radiation-responsive proteins in C. reinhardtii. Our data should provide molecular insights into gamma radiation responses including DNA damage in green algae.

Radiation Shielding Effects of Tungsten and Boron Carbide Coating Materials Fabricated by HVOF Techniuqe

Beom Kyu Kim,Seung Heon Baek,Geun Dong Song,Yeong Ho Son,Jae Hun Lee,Young Jin Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

This study focuses on the development of coatings designed for storage containers used in the management of radioactive waste. The primary objective is to enhance the shielding performance of these containers against either gamma or neutron radiation. Shielding against these types of radiation is essential to ensure the safety of personnel and the environment. In this study, tungsten and boron cabide coating specimens were manufactured using the HVOF (High-Velocity Oxy Fuel) technuqe. These coatings act as an additional layer of protection for the storage containers, effectively absorbing and attenuating gamma and neutron radiation. The fabricated tungsten and boron carbide coating specimens were evaluated using two different testing methods. The first experiment evaluates the effectiveness of a radiation shielding coating on cold-rolled steel surfaces, achieved by applying a mixture of WC (Tungsten Carbide) powders. WC-based coating specimens, featuring different ratios, were prepared and preliminarily assessed for their radiation shielding capabilities. In the gamma-ray shielding test, Cs-137 was utilized as the radiation source. The coating thickness remained constant at 250 μm. Based on the test results, the attenuation ratio and shielding rate for each coated specimen were calculated. It was observed that the gammaray shielding rate exhibited relatively higher shielding performance as the WC content increased. This observation aligns with our findings from the gamma-ray shielding test and underscores the potential benefits of increasing the tungsten content in the coating. In the second experiment, a neutron shielding material was created by applying a 100 μm-thick layer of B4C (Boron Carbide) onto 316SS. The thermal neutron (AmBe) shielding test results demonstrated an approximate shielding rate of 27%. The thermal neutron shielding rate was confirmed to exceed 99.9% in the 1.5 cm thick SiC+B4C bulk plate. This indicates a significant reduction in required volume. This study establishes that these coatings enhance the gamma-ray and neutron shielding effectiveness of storage containers designed for managing radioactive waste. In the future, we plan to conduct a comparative evaluation of the radiation shielding properties to optimize the coating conditions and ensure optimal shielding effectiveness.

저선량 ${\gamma}$선이 기냐 생산된 감자 소괴경의 휴면과 생에 미치는 효과

김동희,백명화,전재흥,김재성,Kim, Dong-Hee,Back, Myung-Hwa,Jeon, Jae-Heung,Kim, Jae-Sung 한국환경생물학회 2001 환경생물 : 환경생물학회지 Vol.19 No.4

저선량 ${\gamma}$선 조사가 기내 유기한 대지와 수미 감자 소괴경의 맹아율과 식물체 생장 및 생리활성에 미치는 효과 등을 알아보고자 감자 소괴경의 저장기간별로 ${\gamma}$선을 0.5${\sim}$30Gy 까지 조사하여 pot실험을 수행하였다. 감자 소괴경의 휴면과 생육에 대한 저선량 ${\gamma}$선 효과는 품종과 저장기간에 따라 다소 차이가 있었다. 대지 품종의 경우 대체로 2,4,8Gy에서 대조구에 비해 높은 맹아 출현율을 보였고, 온실 재배에서는 4,8,16Gy에서 비교적 양호한 생육과 수량 증가 효과를 보였다. 수미 품종에서의 맹아 출현은 2Gy와 4Gy에서 촉진되었고 0.5Gy와 4Gy에서 양호한 생육 및 수량을 보였다. 엽록소 함량은 저선량 ${\gamma}$선 조사구에서 대조구에 비해 뚜렷한 증가효과를 보이지 않았다. 이에 저선량 ${\gamma}$선이 감자의 휴면타파와 생육촉진에 효과가 있음을 확인할 수가 있었다. To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers induced in vitro of two potato (Solanum tuberosum L. cv. Dejima and cv. Superior) cultivars with different storage duration were irradiated with ${\gamma}$ radiation at the dose of $0.5{\sim}30$ Gy. Sprouting rate, growth and tuber yield of ‘Dejima’ microtuber were increased by ${\gamma}$ radiation in the range of $2{\sim}16$ Gy. In the microtuber of ‘Superior’, the sprouting rate was promoted by 2 Gy and 4 Gy irradiation, and the growth and tuber yield by 0.5 Gy and 4 Gy irradiation. There were not that much difference in chlorophyll content of potato plantlet by the low dose ${\gamma}$ irradiation. These results suggested that low dose ${\gamma}$ radiation stimulated the dormancy breaking and potato growth.

저선량 $\gamma$선 조사가 참박의 초기 생육과 효소 활성 및 광합성 능에 미치는 영향

이혜연,김재성,백명화,이영근,임돈순 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.3

저선량 $\gamma선 조사가 참박의 초기생육과 생리활성에 미치는 효과를 알아보기 위하여 참박 종자에 $\gamma선을 0-2O Gy 수준으로 조사하여 생육을 관찰하였다. 저선량 $\gamma선에 의한 참박의 초기생육은 대조구에 비해 4-16Gy에서 다소 증가하였고, 생육 조사시 측정한 자엽의 경우 catalase와 Peroxidase 활성이 대조구에 비해 8 Gy 조사구에서 가장 높았으며 본엽은 peroxidase활성이 4 Gy 조사구에서 확연히 증가하였다. 저선량 $\gamma선을 조사한 박 식물체의 광 스트레스에 대한 반응효과는 광계II의 광화학적 효율이 대조구와 8 Gy의 경우 50% 정도 감소되었으나 4 Gy에서는 40% 정도의 감소를 보였다. 반면 Fo는 광저해가 진행됨에 따라 약간의 증가를 보였으나 대조구나 저선량 조사구사이의 차이는 거의 없는 것으로 나타났다. 광계II의 광양자 수율, $\varphi_{PSII}$과 광계II 반응중심의 흥분 포획능, 1/Fo-l/Fm 또한 광저해가 진행되는 동안 감소하여 $\varphi_{PSII}$는 대조구와 8 Gy의 경우 20% 정도 감소를 보인 반면 4 Gy 조사구는 15%의 감소를 보였고, 1/Fo-lF/m은 대조구와 8 Gy는 55%, 4 Gy는 45%의 감소를 나타냈다. 비광화학적 소멸인 NPQ는 대조구와 저선량 조사구 모두 70% 정도 감소되는 경향을 보였다. 이러한 결과를 볼 때 종자의 종피를 투과한 저선량의 $\gamma선이 참박의 생육을 촉진시키고 4 Gy에서 광 스트레스에 대한 저해가 감소되었다. Gourd seeds were irradiated with the doses of 0-20 Gy to investigate the effect of the low dose $\gamma$-radiation on the early growth and physiological activity. The stimulating effects of the low dose y- radiation on the early growth were not noticeably high, but were increased generally at 4-16 Gy irradiation group. The catalase and peroxidase activity of cotyledon from seeds irradiated with $\gamma$- radiation were increased at 8 Gy irradiation group. The photochemical activity of leaf was noticeably high at 4 Gy irradiation group. The photochemical yield of PSII, estimated as Fv/Fm, decreased with increasing illumination time by 50% after 4 hrs in the control and 8 Gy irradiation group, while Fo slightly increased. However, Fv/Em in the 4 Gy irradiation group decreased by 40% of inhibition, indicating that photoinhibition decreased by the low dose $\gamma$- radiation. Changes in the effective quantum yield of PSII, $\varphi_{PSII}$ and 1/Fo- l/Fm, a measure of the rate constant of excitation trapping by the PSII reaction center, showed similar pattern to Fv/Em. NPQ decreased by 70% after photoinhibitory treatment with showing similar pattern between the control and the irradiation group. These results showed the positive effect of low dose $\gamma$- radiation on the seedling growth and the reduction of photoinhibition in the 4 Gy irradiation group.

장기 중선량률 감마선 피폭에 의한 마우스의 생존율 및생물학적 영향 평가

김재경,진영배,오수미,이윤종,성낙윤,송범석,박종흠,변의백,이주운,김재훈 한국방사선산업학회 2013 방사선산업학회지 Vol.7 No.2

Late effects of chronic exposure to gamma radiation are potential hazards to workerin radiation facilities as well as to the general public. Recently, chronic gamma radiation exposureeffects have become a serious concern. Using a total of 60 mice, we studied the biological effects ofmedium-dose chronic exposure to gamma radiation. Sixty female 6-week-old specific pathogenfree Balb/c mice were randomly divided into six groups (five groups irradiated and one non-irradiatedcontrol group). Irradiation was carried out for 7 days using gamma rays at dose rates of119.65, 238.10, 357.14, 476.19 and 595.24 mGy h-1 with total doses 20, 40, 60, 80 and 100 Gy. Afterirradiation, we determined survival rate of gamma radiation exposed mice during 1 week and476.19 and 595.24 mGy h-1 exposed group mice showed less 10% of survival rate. Otherwise,119.65, 238.10 and 357.14 mGy 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 from119.65, 238.10 and 357.14 irradiated group mice showed significant decreased. However, no significantalteration was observed between 119.65, 238.10 and 357.14 mGy h-1 irradiated group. Overall, our results show for the first time that medium-dose chronic gamma radiation has thepotential to stimulation of biological effects.

저선량 ${\gamma}$ 선 조사가 배추와 무 종자의 발아와 양분흡수에 미치는 영향

윤영만,김남범,김재성,김정규,Yoon, Young-Man,Kim, Nam-Bum,Kim, Jae-Sung,Kim, Jeong-Gyu 한국환경농학회 1999 한국환경농학회지 Vol.18 No.4

배추와 무의 영양생리에 대한 저선량${\gamma}$선에 의한 자극작용의 영향을 파악하고자 1998년산 흑진주배추, 1995년산 서림엇갈이배추, 1998년산 청운무 종자에 1에서 10Gy의 저선량 ${\gamma}$선을 조사하고 생육시기에 따른 생장량과 무기양분의 변화를 분석하였다. 공시된 배추품종들은 조사선량의 증가에 따라서 발아율과 건물생산량이 증가하는 경향을 보였다. 건물생산의 증가는 흑진주배추에서 가장 현저하여 10Gy 처리구에서 143%로 증가되었고, 서림엇갈이배추는 10Gy에서 138%로 증가하였다. 청운무는 ${\gamma}$선 조사에 따른 발아율과 건물생산량의 일관된 경향성을 보이지 않았다. 무기영양소들의 함량변화는 선량-반응 곡선의 ${\gamma}$ 또는 ${\delta}$형을 나타내 ${\gamma}$선에 의한 자극효과가 일부처리구에서 나타나기는 하였지만 일반적 현상이라고 인정하기 어려웠다. 따라서 저선량 ${\gamma}$조사가 배추와 무의 영양생리에 미치는 영향을 정확하게 파악하기 위한 연구결과의 집적이 필요할 것으로 판단된다. To investigate hormetic effect of low dose ${\gamma}$-ray on the uptake of mineral nutrients in Chinese cabbage (Brassica campestris var. Hekjinju var. Surim and) and radish (Raphanus sativas var. Chung-un), seeds of these plants were irradiated with the dose of 1 to 10 Gy. Germination rate and dry weight were examined at pot experiment in greenhouse. Samples for analysis of mineral nutrient were harvested at 17 days and at 59 days after seedling and were analyzed by ICP. Brassica campestris varieties showed higher germination rate and dry weight production with increasing ${\gamma}$ ray dose. Dry weight of Hekjinju Surim and were 143% and 138% at 10Gy dose. respectively. There was no tendency in germination rate and dry weight production for Raphanus sativas var. Chung-un with ${\gamma}$-ray irradiation. The pattern of mineral nutrient content of these plants showed ${\gamma}$ or ${\delta}$ type of dose-reaction curve with no siginificant. This investigation suggests that the more results can be required to understand the hormetic effect of low dose ${\gamma}$ ray on the uptake of mineral nutrient for these plants.

VARIATION OF NEUTRON MODERATING POWER ON HDPE BY GAMMA RADIATION

Park, Kwang-June,Ju, June-Sik,Kang, Hee-Young,Shin, Hee-Sung,Kim, Ho-Dong The Korean Association for Radiation Protection 2009 방사선방어학회지 Vol.34 No.1

High density polyethylene (HDPE) is degraded due to a radiation-induced oxidation when it is used as a neutron moderator in a neutron counter for a nuclear material accounting of spent fuels. The HDPE exposed to the gamma-ray emitted from the fission products in a spent nuclear fuel results in a radiation-induced degradation which changes its original molecular structure to others. So a neutron moderating power variation of HDPE, irradiated by a gamma radiation, was investigated in this work. Five HDPE moderator structures were exposed to the gamma radiation emitted from a $^{60}Co$ source to a level of $10^5-10^9$ rad to compare their post-irradiation properties. As a result of the neutron measurement test with 5 irradiated HDPE structures and a neutron measuring system, it was confirmed that the neutron moderating power for the $10^5$ rad irradiated HDPE moderator revealed the largest decrease when the un-irradiated pure one was used as a reference. It implies that a neutron moderating power variation of HDPE is not directly proportional to the integrated gamma dose rate. To clarify the cause of these changes, some techniques such as a FTIR, an element analysis and a densitometry were employed. As a result of these analyses, it was confirmed that the molecular structure of the gamma irradiated HDPEs had partially changed to others, and the contents of hydrogen and oxygen had varied during the process of a radiation-induced degradation. The mechanism of these changes cannot be explained in detail at present, and thus need further study.

Developmental inhibition of Drosophila suzukii by ionizing radiation

김준헌,김정민,이연정,박정규 한국곤충학회 2018 Entomological Research Vol.48 No.5

Spotted wing drosophila (SWD) has emerged as a major invasive insect pest of small berry fruits in the Americas and Europe since the late 2000s. Thus, phytosanitary treatment of commodities for export is imperative to prevent the movement of viable SWD to newer areas. In the present study, all developmental stages of SWD were irradiated with different doses of gamma and electron beam radiation to assess developmental inhibition to identify potential quarantine doses of the radiations. Ionizing radiation induced developmental inhibition of all stages of SWD. The effective doses for 99% inhibition (ED99) of hatching, pupariation, and adult emergence from irradiated eggs for gamma radiation were 882, 395 and 39 Gy, respectively, compared with 2849, 687, and 41 Gy, respectively, for electron beam radiation. The ED99 for inhibition of pupariation and adult emergence in irradiated larvae were 703 and 47 Gy, respectively, for gamma radiation, and 619 and 33 Gy, respectively, for electron beam radiation. Pupal irradiation did not completely inhibit adult emergence, even at 300 Gy. However, irradiation with ≥100 Gy of puparia induced adult sterility, with no egg production at all. The ED99 for inhibition of F1 egg hatchability from adults irradiated with gamma radiation and electron beam radiation was estimated to be 424 and 125 Gy, respectively. The results of the present study suggest that gamma radiation and electron beam radiation are alternatives for phytosanitary treatment. Irradiation with 100 Gy could be suggested as a potential dose for egg, larval, and pupal quarantine treatment of SWD.

Development and Characterization of a Phoswich Radiation Sensor to Simultaneously Measure the Count Rates and Energies of Beta and Gamma Radiation

주한영,김재욱,문주현 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.10

In this research, we developed and characterized a phoswich radiation sensor (PHORS) to simultaneously measure the count rates and the energies of beta and gamma radiation. The proposed PHORS device comprises a sensing probe combining NaI(Tl) and CaF2(Eu) scintillators for simultaneous measurement of beta and gamma radiation, a multichannel analyzer to characterize the radiation energy, and a laptop computer for signal analysis. For its performance test, we employed a prototype PHORS to measure the energies and the count rates of beta and gamma radiation from three different radiation sources for separation distances from 2 to 10 cm. The count rates of the PHORS were consistent with expected rates, and the captured energy spectra showed classic radionuclide characteristics. Thus, the proposed PHORS system provides an effective and facile tool to detect beta and gamma radiation simultaneously and to identify radionuclides from the captured energy spectra.

Using machine learning for anomaly detection on a system-on-chip under gamma radiation

Wächter Eduardo Weber,Kasap Server,Kolozali Şefki,Zhai Xiaojun,Ehsan Shoaib,McDonald-Maier Klaus D. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11

The emergence of new nanoscale technologies has imposed significant challenges to designing reliable electronic systems in radiation environments. A few types of radiation like Total Ionizing Dose (TID) can cause permanent damages on such nanoscale electronic devices, and current state-of-the-art technologies to tackle TID make use of expensive radiation-hardened devices. This paper focuses on a novel and different approach: using machine learning algorithms on consumer electronic level Field Programmable Gate Arrays (FPGAs) to tackle TID effects and monitor them to replace before they stop working. This condition has a research challenge to anticipate when the board results in a total failure due to TID effects. We observed internal measurements of FPGA boards under gamma radiation and used three different anomaly detection machine learning (ML) algorithms to detect anomalies in the sensor measurements in a gamma-radiated environment. The statistical results show a highly significant relationship between the gamma radiation exposure levels and the board measurements. Moreover, our anomaly detection results have shown that a One-Class SVM with Radial Basis Function Kernel has an average recall score of 0.95. Also, all anomalies can be detected before the boards are entirely inoperative, i.e. voltages drop to zero and confirmed with a sanity check.