• 한국산업보건학회지
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• 제28권3호
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• pp.283-291
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• 2018

Objectives: To monitor the radon concentration level in plants that handle phosphorus rock and produce gypsum board and cement, and evaluate the effective dose considering the effect of radon exposure on the human body. Methods: Airborne radon concentrations were measured using alpha-track radon detectors (${\alpha}$-track, Rn-tech Co., Korea) and continuous monitors (Radon Sentinel 1030, Sun Nuclear Co., USA). Radon concentrations in the air were converted to radon doses using the following equation to evaluate the human effects due to radon. H (mSv/yr) = Radon gas concentration x Equilibrium factor x Occupancy factor x Dose conversion factor. The International Commission on Radiological Protection (ICRP) used $8nSv/(Bq{\cdot}hr/m^3)$ as the dose conversion factor in 2010, but raised it by a factor of four to $33nSv/(Bq{\cdot}hr/m^3)$ in 2017. Results: Radon concentrations and effective doses in fertilizer manufacturing process averaged $14.3(2.7)Bq/m^3$ ($2.0-551.3Bq/m^3$), 0.11-0.54 m㏜/yr depending on the advisory authority and recommendation year, respectively. Radon concentrations in the gypsum-board manufacturing process averaged $14.9Bq/m^3$ at material storage, $11.4Bq/m^3$ at burnability, $8.1Bq/m^3$ at mixing, $10.0Bq/m^3$ at forming, $8.9Bq/m^3$ at drying, $14.7Bq/m^3$ at cutting, and $10.5Bq/m^3$ at shipment. It was low because it did not use phosphate gypsum. Radon concentrations and effective doses in the cement manufacturing process were $23.2Bq/m^3$ in the stowage area, $20.2Bq/m^3$ in the hopper, $16.8Bq/m^3$ in the feeder and $11.9Bq/m^3$ in the cement mill, marking 0.12-0.63 m㏜/yr, respectively. Conclusions: Workers handling phosphorous gypsum directly or indirectly can be assessed as exposed to an annual average radon dose of 0.16 to 2.04 mSv or 0.010 to 0.102 WLM (Working Level Month).

• Journal of Radiation Protection and Research
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• 제31권2호
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• pp.53-63
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• 2006

원전 종사자를 대상으로 경시적인 코호트 연구를 통하여 저준위 방사선 노출과 암 발생 위해도를 규명하고자 하였다. 방사선 노출에 관한 정보는 한국수력원자력(주)의 방사선 관리 DB에서 수집하였고, 암 발생에 관한 정보는 한국인 중앙 암 등록 자료를, 암 사망에 관한 정보는 통계청 사망원인 자료를 이용하여 수집하였다. 방사선 노출과 암 발생 위해도는 표준화 암 사망비(SMR)와 표준화 암 발생 비(SIR)로 평가하였다. 노출 군에서 암 발생에 대한 상대위험도는 1.08로 평가되었으나 전체 암에 대한 SIR은 0.81로 유의성이 관찰되지 않았다. 암 사망에 대한 상대위험도는 1.21 이었으나 전체 암에 대한 SMR도 0.86으로 역시 유의성은 관찰되지 않았다. 암 유형별 양상은 우리나라 일반인과 유사한 결과를 보였으며, 방사선량 증가에 따른 양-반응 관계 또한 확인되지 않았다.

• Toxicological Research
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• 제34권4호
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• pp.343-354
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• 2018

Aluminum oxide nanoparticles ($Al_2O_3$ NPs) are among the most widely used nanomaterials; however, relatively little information about their risk identification and assessment is available. In the present study, we aimed to investigate the potential toxicity of $Al_2O_3$ NPs following repeated inhalation exposure in male Sprague-Dawley rats. Rats were exposed to $Al_2O_3$ NPs for 28 days (5 days/week) at doses of 0, 0.2, 1, and $5mg/m^3$ using a nose-only inhalation system. During the experimental period, we evaluated the clinical signs, body weight change, hematological and serum biochemical parameters, necropsy findings, organ weight, and histopathology findings. Additionally, we analyzed the bronchoalveolar lavage fluid (BALF), including differential leukocyte counts, and aluminum contents in the major organs and blood. Aluminum contents were the highest in lung tissues and showed a dose-dependent relationship in the exposure group. Histopathology showed alveolar macrophage accumulation in the lungs of rats in the $5mg/m^3$ group during exposure and recovery. These changes tended to increase at the end of the recovery period. In the BALF analysis, total cell and neutrophil counts and lactate dehydrogenase, tumor necrosis factor-${\alpha}$, and interleukin-6 levels significantly increased in the 1 and $5mg/m^3$ groups during exposure. Under the present experimental conditions, we suggested that the no-observed-adverse-effect level of $Al_2O_3$ NPs in male rats was $1mg/m^3$, and the target organ was the lung.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1784-1791
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• 2020

The 14 MeV neutron generator facility is being developed by the Institute for Plasma Research India to conduct the lab scale experiments related to Indian breeding blanket system for ITER and DEMO. It will also be utilized for material testing, shielding experiments and development of fusion diagnostics. Occupational radiation exposure control is necessary for the all kind of nuclear facilities to get the operational licensing from governing authorities and nuclear regulatory bodies. In the same way, the radiation exposure for the 14 MeV neutron generator facility at the occupational worker area and accessible zones for general workers should be under the permissible limit of AERB India. The generator is designed for the yield of 10¹² n/s. The shielding assessment has been made to estimate the radiation dose during the operational time of the neutron generator. The facility has many utilities and constraints like ventilation ducts, accessible doors, accessibility of neutron generator components and to conduct the experiments which make the shielding assessment challenging to provide proper safety for occupational workers and the general public. The neutron and gamma dose rates have been estimated using the MCNP radiation transport code and ENDF -VII nuclear data libraries. The ICRP-74 fluence to dose conversion coefficients has been used for the assessment. The annual radiation exposure has been assessed by considering 500 h per year operational time. The provision of local shield near to neutron generator has been also evaluated to reduce the annual radiation doses. The comprehensive results of radiation shielding capability of neutron generator building and local shield design have been presented in the paper along with detailed maps of radiation field.

• Archives of Pharmacal Research
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• 제28권1호
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• pp.100-105
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• 2005

Mancozeb (MCZ) is known to have detrimental effects on the reproductive system, but the toxicity of MCZ on immune responses has not been systematically investigated. We investigated the effects of MCZ exposure on the activities of murine peritoneal macrophages through evaluation of MCZ-induced alteration of nitric oxide (NO) production and tumor necrosis $factor-{\alpha}(TNF-\alpha)$ synthesis. Macrophages were examined ex vivo from mice orally treated with various doses of MCZ for 5 consecutive days per week for 4 weeks (subacute exposure, 250, 1000, 1500 mg/kg/day) followed by culture for 2 $(TNF-{\alpha})$ or 3 days (NO) in the presence of LPS plus $IFN-{\gamma}$. Macrophages from naive mice were also cultured with various concentrations of MCZ (0.05, 0.25, 0.5, 1 and 2 ${\mu}g//mIL$ in the presence of LPS plus $IFN-{\gamma}$ for 2 $(TNF-{\alpha})$ or 3 days (NO) in vitro. NO production was decreased with the in vitro exposure to all concentrations of MCZ. However, the amount of NO production by peritoneal macrophages from MCZ-subacutely exposed mice was increased in comparision with that of control group. In vitro, MCZ suppressed $(TNF-\alpha)$ secretion with significant reduction at 2 ${\mu}g/mL$ MCZ. Conversely, $(TNF-{\alpha})$ release was enhanced ex vivo. This study provides the substantial evidence on MCZ-induced alternation in macrophage activity. In order to clearly understand the contrasting effect of MCZ on peritoneal macrophage activity, it is necessary to further investigate the influence of major metabolite of MCZ (ETU) exposure on the NO production and $(TNF-{\alpha})$ synthesis.

• 한국양식학회지
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• 제11권1호
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• pp.59-66
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• 1998

버들치 Rhynchocypris oxycephalus와 버들개 R. steindachneri를 대상으로 마취 수온 10도C, 15도C 및 20도C에서 염산리도카인(염산리도카인/NaHCO하(3))의 마취 효과를 조사하였다. 마취 시간과 회복 시간을 고려시 효과적인 염산리도카인 농도는 버들치에서 300ppm ($20^{\circ}C.$), 400ppm ($15^{\circ}C.$) 및 600ppm ($10^{\circ}C.$) 이었고 버들개에서 400ppm ($20^{\circ}C.$), 500ppm ($15^{\circ}C.$) 및 600ppm ($10^{\circ}C.$) 이었다. 마취시간과 회복시간에 있어 버들치 속 2종은 염산리도카인 농도 및 마취 수온 의존적이었다. 각 염산리도카인 농도에서 개체 크기가 증가할수록 마취 시간이 길어졌으며, 개체 크기가 큰 군은 마취 농도가 증가할수록 회복 시간 역시 길어졌다. 본 연구 결과 염산리도카인은 버들치 속어류 마취에 효과적인 것으로 판명되었다.

• 치과방사선
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• 제18권1호
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• pp.31-45
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• 1988

The author studied the histopathologic changes according to a single or a split dose and the time after irradiation on the acinar cells of rat parotid gland. 99 Sprague Dawley rats, weighing about l20gm, were divided into control and 3 experimental groups. In experimental groups, GroupⅠ and Ⅱ were delivered a single dose of l5Gy, 18Gy and Group Ⅲ and Ⅳ were delivered two equal split doses of 9Gy, 10.5Gy for a 4 hours interval, respectively. The experimental groups were delivered by a cobalt-60 teletherapy unit with a dose rate of 222cGy/min, source-skin distance of 50㎝, depth of l㎝ and a field size of l2×5㎝. The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and examined by light and electron microscopy. The results were as follows: 1. As the radiation dose increased and the acinar cells delivered a single dose exposure were more damaged, and the change of acinar cells appeared faster than those of a split dose exposure. 2. The histopathologic change of acinar cells appeared at 1 hour after irradiation. The recovery from damaged acinar cells appeared at 1 day after irradiation and there was a tendency that the recovery from damage of a split dose exposure was somewhat later than that of a single dose exposure. 3. Light microscope showed atrophic change of acinar cells and nucleus, degeneration and vesicle formation of cytoplasm, widening of intercellular space and interlobular space. 4. Electron microscope showed loss of nuclear membrane, degeneration of nucleus and nucleoli, clumping of cytoplasm, widening and degeneration of rough endoplasmic reticulum, loss of cristae of mitochondria, lysosome, autophagosome and lipid droplet. 5. Electron microscopically, the change of rough endoplasmic reticulum was the most prominent and this appeared at 1 hour after irradiation as early changes of acinar cells. The nuclear change appeared at 2 hours after irradiation and the loss of cristae of mitochondria was observed at 2 hours after irradiation in all experimental groups.

• 한국방사선학회논문지
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• 제5권6호
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• pp.421-426
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• 2011

본 연구는 CR영상에서 선량이 화질에 미치는 영향을 평가하기위해 수행되었다. 본 연구의 궁극적인 목적은 임상 흉부진단에 필요한 영상화질을 얻을 수 있는 최적 선량을 찾는 것이다. 영상화질 평가를 위해서 다양한 선량에서의 MTF, NNPS, 그리고 NEQ를 측정하였으며, MTF 측정과 실험장치 구성은 International Electrotechnical Commission(IEC)에서 제시한 절차에 따라 수행하였다. 실험 결과를 통해 흉부진단의 경우 자동노출조절 (Automatic Exposure Control, AEC) 제어반에서 자동으로 설정해주는 선량의 절반 선량으로도 필요한 영상화질이 얻어짐을 알 수 있었다. 본 연구를 통해 AEC에서 제시하는 선량이 최적 선량이 아니며 화질평가를 통해서 얻어진 최적 선량을 사용하면 환자의 피폭을 상당량 줄일 수 있음을 보였다.

• Journal of Radiation Protection and Research
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• 제32권3호
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• pp.111-115
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• 2007

원자력 발전소의 중수누출에 따른 삼중수소 농도증가에 의한 방사선 내부피폭과 이에 대한건강영향평가를 실시하였다. 전체 22명 가운데 13명에 대하여 검사를 실시하였으며, 이들의 내부피폭량은 $0{\sim}4.44\;mSv$ 였다. 일반혈액검사 중 백혈구수치의 변화를 이용하여 평가한 결과에서 결정적 영향에 대한 특이사항은 나타나지 않았으며, 생물학적 선량평가 방법을 이용한 체내피폭량은 $0{\sim}37\;mGy$로 확인되었다. 결론적으로 방사선 피폭은 허용한도를 초과하지 않았으며, 결정적 영향인 임상적 증상이 보이지 않았다. 이와 같이 의학적 징후와 선량평가 추정치와의 일치성은 사고시 특히 물리적 생물학적 선량평가가 유용함을 보여 준다.

• Nutrition Research and Practice
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• 제12권1호
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• pp.41-46
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• 2018

BACKGROUND/OBJECTIVES: Exposure of the normal lung tissue around the cancerous tumor during radiotherapy causes serious side effects such as pneumonitis and pulmonary fibrosis. Radioprotectors used during cancer radiotherapy could protect the patient from side effects induced by radiation injury of the normal tissue. Delphinidin has strong antioxidant properties, and it works as the driving force of a radioprotective effect by scavenging radiation-induced reactive oxygen species (ROS). However, no studies have been conducted on the radioprotective effect of delphinidin against high linear energy transfer radiation. Therefore, this study was undertaken to evaluate the radioprotective effects of delphinidin on human lung cells against a proton beam. MATERIALS/METHODS: Normal human lung cells (HEL 299 cells) were used for in vitro experiments. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay assessed the cytotoxicity of delphinidin and cell viability. The expression of radiation induced cellular ROS was measured by the 2'-7'-dicholordihydrofluorescein diacetate assay. Superoxide dismutase activity assay and catalase activity assay were used for evaluating the activity of corresponding enzymes. In addition, radioprotective effects on DNA damage-induced cellular apoptosis were evaluated by Western blot assay. RESULTS: Experimental analysis, including cell survival assay, MTT assay, and Western blot assay, revealed the radioprotective effects of delphinidin. These include restoring the activities of antioxidant enzymes of damaged cells, increase in the levels of pro-survival protein, and decrease of pro-apoptosis proteins. The results from different experiments were compatible with each to provide a substantial conclusion. CONCLUSION: Low concentration ($2.5{\mu}M/mL$) of delphinidin administration prior to radiation exposure was radioprotective against a low dose of proton beam exposure. Hence, delphinidin is a promising shielding agent against radiation, protecting the normal tissues around a cancerous tumor, which are unintentionally exposed to low doses of radiation during proton therapy.