• Journal of Radiation Protection and Research
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• v.47 no.1
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• pp.30-38
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• 2022

Background: Residential areas have some factors on the external exposure of residents, who usually spend a long time in these areas. Although various survey has been carried out by the government or the research institutions after the Fukushima Daiichi Nuclear Power Plant accident, the mechanism of radiocesium inventory in the terrestrial zone has not been cleared. To better evaluate the radiation environment, this study investigated the temporal changes in air dose rate and ¹³⁷Cs inventories (Bq/m²) in residential areas and agricultural fields. Materials and Methods: Air dose rate and ¹³⁷Cs inventories were investigated in residential areas located in an evacuation zone at 5-8 km from the Fukushima Daiichi Nuclear Power Plant. From December 2014 to September 2018, the air dose rate distribution was investigated through a walking survey (backpack survey), which was conducted by operators carrying a γ-ray detector on their backs. Additionally, from December 2014 to January 2021, the ¹³⁷Cs inventories on paved and permeable grounds were also measured using a portable γ-ray detector. Results and Discussion: In the areas where decontamination was not performed, the air dose rate decreased faster in residential areas than in agricultural fields. Moreover, the ¹³⁷Cs inventory on paved surfaces decreased with time owing to the horizontal wash-off, while the ¹³⁷Cs inventory on permeable surfaces decreased dramatically owing to the decontamination activities. Conclusion: These findings suggest that the horizontal wash-off of ¹³⁷Cs on paved surfaces facilitated the air dose rate decrease in residential areas to a greater extent compared with agricultural fields, in which the air dose rate decreased because of the vertical migration of ¹³⁷Cs. Results of this study can explain the faster environmental restoration in a residential environment reported by previous studies.

• Nuclear Engineering and Technology
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• v.46 no.4
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• pp.547-556
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• 2014

Korea expects a shortage in storage capacity for spent fuels at reactor sites. Therefore, a need for more metal and/or concrete casks for storage systems is anticipated for either the reactor site or away from the reactor for interim storage. For the purpose of interim storage and transportation, a dual purpose metal cask that can load 21 spent fuel assemblies is being developed by Korea Radioactive Waste Management Corporation (KRMC) in Korea. At first the gamma and neutron flux for the design basis fuel were determined assuming in-core environment (the temperature, pressure, etc. of the moderator, boron, cladding, $UO_2$ pellets) in which the design basis fuel is loaded, as input data. The evaluation simulated burnup up to 45,000 MWD/MTU and decay during ten years of cooling using the SAS2H/OGIGEN-S module of the SCALE5.1 system. The results from the source term evaluation were used as input data for the final shielding evaluation utilizing the MCNP Code, which yielded the effective dose rate. The design of the cask is based on the safety requirements for normal storage conditions under 10 CFR Part 72. A radiation shielding analysis of the metal storage cask optimized for loading 21 design basis fuels was performed for two cases; one for a single cask and the other for a $2{\times}10$ cask array. For the single cask, dose rates at the external surface of the metal cask, 1m and 2m away from the cask surface, were evaluated. For the $2{\times}10$ cask array, dose rates at the center point of the array and at the center of the casks' height were evaluated. The results of the shielding analysis for the single cask show that dose rates were considerably higher at the lower side (from the bottom of the cask to the bottom of the neutron shielding) of the cask, at over 2mSv/hr at the external surface of the cask. However, this is not considered to be a significant issue since additional shielding will be installed at the storage facility. The shielding analysis results for the $2{\times}10$ cask array showed exponential decrease with distance off the sources. The controlled area boundary was calculated to be approximately 280m from the array, with a dose rate of 25mrem/yr. Actual dose rates within the controlled area boundary will be lower than 25mrem/yr, due to the decay of radioactivity of spent fuel in storage.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6523-6526
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• 2012

Objective: This study was designed to investigate treatment efficacy and side effects of concomitant Aisu$^{(R)}$ (docetaxel) with three-dimensional conformal external beam radiotherapy for the treatment of inoperable patients with esophageal cancer. Methods: Inoperable patients were treated with three-dimensional conformal external beam radiotherapy (5/week, 2 GY/day, and total dose 60GY) plus docetaxel ($30-45mg/m^2$, iv, d1, 8). Results: Twenty eight patients met the study eligibility criteria and the response rate was evaluated according to RICIST guidelines. Among 28 patients, 2 achieved CR, 22 PR, 3 SD and 1 patient was documented PD. Mild gastrointestinal reaction and bone marrow suppression were also documented. All treatment related side effects were tolerable. Conclusion: Three-dimensional conformal external beam radiotherapy combined with docetaxel is an active and safe regimen for inoperable patients with esophageal cancer.

• Toxicological Research
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• v.28 no.2
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• pp.99-102
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• 2012

Bee venom (Apis mellifera L. BV) has been used as a cosmetic ingredient for anti-ageing, anti-inflammatory and antibacterial functions. The aim of this study was to evaluate the acute toxicity after a single dermal administration of BV, BV was administered to 2 groups of Sprague-Dawley (SD) male and female rats (5 animals/group) at doses of 0 and 1,500 mg/kg body weight (BW). Mortality, clinical signs, body weight changes and gross findings were continually monitored for 15 days following the single dose. There were no unscheduled deaths in any groups during the study period. No BV related clinical signs and body weight changes were observed in any groups during the study period. There were no abnormal gross findings at necropsy on day 15 after the treatment. On the basis of the above results, it was concluded that there were no treatment-related effect on mortality, clinical signs, body weight changes and gross findings in SD rats treated with a single dermal dose of BV at dose of 1,500 mg/kg BW. Therefore, the approximate lethal dose of BV was considered to be over 1,500 mg/kg/day for both sexes of rats. BV may provide a developmental basis for a cosmetic ingredient or external application for topical uses.

• The Korean Journal of Community Living Science
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• v.26 no.3
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• pp.511-522
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• 2015

This study investigates the acute and repeated-dose oral toxicity of crude antifungal compounds produced by Lactobacillus plantarum AF1 (Lb. plantarum AF1) and Lactobacillus plantarum HD1 (Lb. plantarum HD1) in male and female Sprague Dawley rats. In the acute toxicity study, crude antifungal compounds (500, 1,000, and 2,000 mg/kg) did not reduce mortality or produce significant changes in general behaviors or the gross appearance of external and internal organs. In the repeated-dose toxicity study, crude antifungal compounds were administered orally to rats at doses of 500, 1,000, and 2,000 mg/kg daily for 28 days. There were no test-article-related deaths, abnormal clinical signs, or body weight changes. In addition, there were no significant differences between groups treated with crude antifungal compounds and the control group in their organ weight, hematological and serum biochemical parameters, or any other factors. These results suggest that the acute or repeated-dose oral administration of crude antifungal compounds produced by Lb. plantarum AF1 plus Lb. plantarum HD1 is not toxic in male and female rats.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2736-2747
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• 2022

The operations in the design lifecycle of a nuclear power plant targeted to be decommissioned lead to neutron activation. Operations in the decommissioning process include cutting, decontamination, disposal, and processing. Among these, cutting is done close to the target material, and thus workers are exposed to radiation. As there are only a few studies on pressurizers, there arises the need for further research to assess the radiation exposure dose. This study obtained the specifications of the AP1000 pressurizer of Westinghouse and the distribution of radionuclide inventory of a pressurizer in a pressurised water reactor for evaluation based on literature studies. A cutting scenario was created to develop an optimal method so that the cut pieces fill a radioactive solid waste drum with dimensions 0.571 m × 0.834 m. The estimated exposure dose, estimated using the tool VISIPLAN SW, in terms of the decontamination factor (DF) ranged from DF-0 to DF-100, indicating that DF-90 and DF-100 meet the ICRP recommendation on exposure dose 0.0057 mSv/h. At the end of the study, although flame cutting was considered the most efficient method in terms of cutting speed, laser cutting was the most reasonable one in terms of the financial aspects and secondary waste.

• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.35-39
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• 2002

Introduction : It is essential to input patients external contour in 3D treatment plan. We would like to see changes in depth and dose when 3D RTP is operating auto contouring when windows value (Width/Level) differs in this process. Material & Methode : We have analyzed the results with 3D RTP after CT Scanning with round CT Phantom. We have compared and analyzed MU values according to depth changes to Isocenter changing external contour and inputting random Window value. We have watched change values according to dose optimization in 4 directions(LAO, LPO, RAO, RPO), We plan 100 case for exact analyzation. We have results changing window value random to each beam in 100 cans. Result : It showed change between minimum and maximum value in 4 beam is Depth 0.26mm, MU $1.2\%$ in LAO. It showed LPO-Depth 0.13mm, MU $0.9\%$, RAO-Depth 0.2mm MU $0.8\%$, RPO-Depth 0.27mm, MU $1.1\%$ Conclusion : Maximum change in depth 0.27 mm, MU error rate is $0.12\%$ according to Window change. As we can see in these results, it seems Window value change doesn't effect in treatment. However, it seems there needs to select appropriate Window value in precise treatment.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.461-466
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• 2011

The feasibility of utilizing food waste leachate as an external carbon source was tested to enhance biological nutrient removal from an industrial wastewater with an average flow rate of $164,800m^3/d$ and a low carbon/nitrogen ratio of 2.8. A considerable improvement in the removal of nitrogen and phosphorus was observed when a certain amount of the leachate, ranging from 70 to $142m^3/d$, was supplemented to the biological industrial wastewater treatment process. The addition of the leachate led to an increase in the BOD/N ratio (4.5) and the removal efficiency of nutritents from 29.7% to 71.7% for nitrogen and from 34.8% to 65.6% for phosphorus. However, an excessive dose of the leachate that significantly exceeded $120m^3/d$ caused serious operational problems, like oil-layer formation in the grit chamber and scum layer in the primary clarifier. Thus, an supplement of food waste leachate at a dose acceptable to an existing facilities can be a practical and effective means to enhance the nutrient removal from industrial wastewater and to dispose of the food waste leachate.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1545-1556
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• 2020

Recently, the International Commission on Radiological Protection (ICRP) has developed the Mesh-type Reference Computational Phantoms (MRCPs) for adult male and female to overcome the limitations of the current Voxel-type Reference Computational Phantoms (VRCPs) described in ICRP Publication 110 due to the limited voxel resolutions and the nature of voxel geometry. In our previous study, the MRCPs were used to calculate the dose coefficients (DCs) for idealized external exposures of photons and electrons. The present study is an extension of the previous study to include three additional particles (i.e., neutrons, protons, and helium ions) into the DC library by conducting Monte Carlo radiation transport simulations with the Geant4 code. The calculated MRCP DCs were compared with the reference DCs of ICRP Publication 116 which are based on the VRCPs, to appreciate the impact of the new reference phantoms on the DC values. We found that the MRCP DCs of organ/tissue doses and effective doses were generally similar to the ICRP-116 DCs for neutrons, whereas there were significant DC differences up to several orders of magnitude for protons and helium ions due mainly to the improved representation of the detailed anatomical structures in the MRCPs over the VRCPs.

• YAKHAK HOEJI
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• v.45 no.2
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• pp.190-204
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• 2001

This study was conducted to investigate for its effects on reproductive and developmental toxicity of recombinant human epidermal growth factor (rhEGF) in Sprague-Dawley rats. Male rats were administered rhEGF at doses of 1, 10, 100, and 1000$\mu$g/kg/day, respective1y, by subcutaneous injection from 63 days before and throughout to mating period until the day before sacrifice. Female rats were administered rhEGF at the same doses from 14 days before mating to day 20 of gestation or to day 21 of lactation. We examined the male and female fertility indices and maternal toxicity of F0 parental animals. Also, we examined the external, visceral, or skeletal malformation of fetuses, growth and development, behavior, and/or reproductive performance of F1 animals. At the highest dose (1,000 $\mu$g/kg), the mean body weights of F0 animals were significantly increased in males and females at 3 or 2 weeks after treatment, respective1y. No clinical signs and food intakes were observed at any time during the experimental period by rhEGF treatment. In autopsy examination, the relative and absolute liver weights significantly increased in both sexes of 1,000 $\mu$g/kg. At the highest dose (1,000 $\mu$g/kg), there was a statistically significant increase of pregnancy period and the number of dead fetuses. Moreover, significant increase of mean fetal body weight and decrease of number of live fetuses, which related to the difficult dilivery were observed in highest dose group. In Fl examination, no adverse effects on external, visceral, and skeletal malformation, physical and functional development, behavior or reproductive ability of Fl animals were observed in any group. Also, there was no significant difference between control and treated groups in copulation or fertility indices of Fl animals. These results indicate that rhEGF had no adverse effect on fertility and reproductive ability of Sprague-Dawley rats.