• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.110-117
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• 2015

Recently, Due to the increased industry using radiation inspection equipment in the semiconductor, this demand of technology research is increasing. Although semiconductor inspection equipment is using low energy X-ray from 40 keV to 120 keV, Studies of radiation damage about the low energy X-ray are lacking circumstance in our country. Therefore, It is study that BJT (bipolar junction transistor) of one type of semiconductor elements are received radiation damage by low energy X-ray. BJT were used to the NXP semiconductor company's BC817-25 (NPN type), and Used the X-ray generator for the irradiation. Radiation damage of BJT was evaluated that confirm to analyse change of collector-emitter voltage of before and after X-ray irradiation when current gain fixed to 10. X-ray generator of tube voltage was setting 40 kVp, 60 kVp, 80 kVp, 100 kVp, 120 kVp and irradiation time was setting 180s, 360s, 540s into 180s intervals. As the result, We confirmed radiation damage in BJT by low energy X-ray under 120 keV energy, and Especially the biggest radiation damage was appeared at the 80 kVp. It is expected that ELDRS (enhanced low dose rate sensitivity) phenomenon occurs on the basis of 80 kVp. This studies expect to contribute effective dose administration of semiconductor inspection equipment using low energy X-ray, Also Research and Development of X-ray filter.

• Korean Journal of Clinical Pharmacy
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• v.31 no.1
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• pp.44-52
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• 2021

Background: Post-transplant immunosuppression with calcineurin inhibitors (CNIs) is associated with kidney function impairment while mammalian target of rapamycin (mTOR) inhibitors, such as everolimus, can be used for its renal-sparing effects. In this study, we compared the efficacy and safety of everolimus with low dose tacrolimus (EVR+Low TAC) and conventional dose tacrolimus (TAC) in liver transplantation recipients. Methods: Medical records of recipients who received liver transplantation at Seoul National University Bundang Hospital from January 1st 2009 to December 31st 2018 were retrospectively reviewed. Cohort entry date was defined as the day everolimus was initiated and tacrolimus dosage was reduced. All patients were followed up for 1 year. Indicator of efficacy was the incidence of rejection and safety was evaluated by incidence of drug adverse events including renal function. Results: Among 118 patients, there were 40 patients (33.9%) in EVR+Low TAC group. Incidence of rejection, including both biopsy proven acute rejection and clinical rejection, was similar in two groups [7.5% (n=3) vs. 6.4% (n=5), p=1.000]. Renal dysfunction was less frequent in EVR+Low TAC [17.5% (n=7) vs. 35.9% (n=28), p=0.038]. However, incidence rates of dyslipidemia, oral ulcer were more frequent in EVR+Low TAC [45.0% (n=18) vs. 21.8% (n=17), p=0.009; 15.0% (n=6) vs. 1.3% (n=1), p=0.006]. Conclusions: In terms of prevention of rejection, EVR+Low TAC was as effective as TAC and had renal-sparing effect but was associated with increased risk of dyslipidemia and oral ulcer. This study demonstrates that EVR+Low TAC could be an alternative to liver transplant recipients with nephrotoxicity after administration of conventional dose tacrolimus.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.240-240
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• 2017

Quinoa (Chenopodium quinoa Willd.) is one of the ancient crops cultivated in the Andes region at an altitude of 3,500-4000m in Chile and Bolivia from 5000 BC. It contains a large amount of protein, minerals and vitamins in comparison with other crops. The cultivation area has been increasing worldwide because of its excellent resistance to various abiotic stress such as salinity, drought and low temperature. ${\gamma}$-Ray radiation of high dose is often used as a tool to induce mutations in plant breeding, but it has a deleterious effect on organisms. However, the radiation may have a positive stimulatory effect of 'hormesis' in the low dose range. This experiment was carried out to investigate the optimum dose range for creating the quinoa genetic resources and to investigate the hormesis effect at low dose on the quinoa. This experiment was performed for 120 days from November, 2016 to February, 2017 in the greenhouse of Gyeongsang National University. ${\gamma}$-Ray radiation was irradiated to seeds at 0 Gy, 50 Gy, 100 Gy, 200 Gy, 300 Gy, 400 Gy, 600 Gy, 800 Gy and 1000 Gy for 8 hours. (50 Gy) using the low level radiation facility ($Co^{60}$) of Cooperative Research Institute of Radiation Research Institute, KAERI. Fifty seeds were placed on each petri dish lined with wet filter paper and germination rate was measured at a time interval of 2 hours for 40 hrs. The length of the root length was measured one week after germination. Each treatment was carried out in 3 replicates. The growth of seedlings were investigated for 10 days after transplanting of 30 day-old seedlings. The plant height, NDVI, SPAD, Fv/Fm, and panicle weight were measured. The germination rate was highest at 50Gy and 0Gy and the rate of seeds treated with 400Gy or higher rate decreased to 25% of the seeds treated with 50Gy. The emergence rate of seedling in pot experiment was higher at the dose of 200 Gy, 300 Gy and 400 Gy than at 0 and 50Gy. However, the rate was lower at strong radiation higher than 600Gy at which $1^{st}$ leaf was not expanded fully and dead due to extreme overgrowth at 44 days after treatment (DAT). The highest value of panicle weight was observed at 50Gy (6.15g) and 100Gy (5.57g). On the other hand, the weight at high irradiated dose of 300Gy and 400Gy was decreased by about 55% compared to low dose (50 Gy). NDVI measurement also showed the highest value at 50 Gy as the growth progressed. SPAD was the highest at 400 Gy and showed positive correlation with irradiation dose except 0 Gy. Fv/Fm was high at 50 Gy up to 30 DAT and no difference between treatments was observed except for 400 Gy from 44 DAT. The plant height was the highest in 50Gy during the growing period and was higher in the order of 50Dy, 100Gy, 0Gy, 200Gy, 300Gy and 400Gy in 88 DAT. In this experiment, the optimal radiation dose for hormesis was 50Gy and 100Gy, and the optimal radiation dose for mutagenesis seems to be 400 Gy.

• Radiation Oncology Journal
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• v.29 no.2
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• pp.63-70
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• 2011

Purpose: To evaluate the extent of pain response and objective response to palliative radiotherapy (RT) for bone metastases from hepatocellular carcinoma according to RT dose. Materials and Methods: From January 2007 to June 2010, palliative RT was conducted for 103 patients (223 sites) with bone metastases from hepatocellular carcinoma. Treatment sites were divided into the high RT dose and low RT dose groups by biologically effective dose (BED) of 39 $Gy_{10}$. Pain responses were evaluated using the numeric rating scale. Pain scores before and after RT were compared and categorized into 'Decreased', 'No change' and 'Increased'. Radiological objective responses were categorized into complete response, partial response, stable disease and progression using modified RECIST (Response Evaluation Criteria In Solid Tumors) criteria; the factors predicting patients' survival were analyzed. Results: The median follow-up period was 6 months (range, 0 to 46 months), and the radiologic responses existed in 67 RT sites (66.3%) and 44 sites (89.8%) in the high and low RT dose group, respectively. A dose-response relationship was found in relation to RT dose (p=0.02). Pain responses were 75% and 65% in the high and low RT dose groups, respectively. However, no statistical difference in pain response was found between the two groups (p=0.24). There were no differences in the toxicity profiles between the high and low RT dose groups. Median survival from the time of bone metastases diagnosis was 11 months (range, 0 to 46 months). The Child-Pugh classification at the time of palliative RT was the only significant predictive factor for patient survival after RT. Median survival time was 14 months under Child-Pugh A and 2 months under Child-Pugh B and C. Conclusion: The rate of radiologic objective response was higher in the high RT dose group. Palliative AT with a high dose would provide an improvement in patient quality of life through enhanced tumor response, especially in patients with proper liver function.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.336-343
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• 2016

Objectives: This study was conducted to analyze the single-dose toxicity and the safety of Mahwangcheonoh pharmacopuncture extracts. Methods: Six-week-old Sprague-Dawley rats were used for this study. Doses of Mahwangcheonoh pharmacopuncture extracts were set at 0.25 mL (low-dose), 0.5 mL (medium-dose) and 1.0 mL (high-dose) for the test groups. A dose of 1.0 mL of normal saline solution was set for the control group. During 14 days, general symptoms, mortalities, and changes in hematology, blood biochemistry and histopathology of all rats were observed. Results: No death was observed in all test groups. Any abnormal symptom was not observed in all of the groups. No significant changes in weight between the control group and the test groups were observed. In addition, no significant differences in the hematology signs, the blood biochemistry levels and the histopathological signs related to the Mahwangcheonoh pharmacopuncture extracts injection were observed. Conclusion: The findings of this study indicate that Mahwangcheonoh pharmacopuncture at doses of 1.0 mL or less may be consider safe and non-toxic. So, it can be used for therapy of obesity sufficiently. But further studies on this subject must be performed to confirm and verify this conclusion.

• Journal of The Korean Society of Clinical Toxicology
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• v.8 no.1
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• pp.1-6
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• 2010

Methylene blue is a very effective reducer of drug-induced methemoglobinemia. It has dose-dependent oxidation or reduction properties. In most cases, a dose of 1 to 2 mg/kg IV given over 5 minutes and immediately followed by a 15- to 30-mL fluid flush to minimize the local pain is both effective and relatively safe. The onset of action is quite rapid, and the effects are usually seen within 30 minutes. The dose may be repeated after 30 to 60 minutes and then every 2 to 4 hours as needed. The total dose should not exceed 7 mg/kg as a single dose or 15 mg/kg within 24 hours. Repeated treatment may be needed for treating compounds that have prolonged elimination or those compounds that undergo enterohepatic recirculation (e.g., dapsone). Methylene blue can cause dose-related toxicity. At high doses, methylene blue can also induce an acute hemolytic anemia and rebound methemoglobinemia. The reasons for treatment failure with methylene blue include ineffective GI decontamination, the existence of other forms of hemoglobin (e.g., sulfhemoglobin), a low or high dose of methylene blue and the toxicokinetics of some agents, such as aniline, benzocaine or dapsone.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.226-232
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• 2015

Purpose: Toxicity of mucosa is one of the major concerns of radiotherapy (RT), when a target tumor is located near a mucosal lined organ. Energy of photon RT is transferred primarily by secondary electrons. If these secondary electrons could be removed in an internal cavity of mucosal lined organ, the mucosa will be spared without compromising the target tumor dose. The purpose of this study was to present a RT dose reduction in near target inner-surface (NTIS) of internal cavity, using Lorentz force of magnetic field. Materials and Methods: Tissue equivalent phantoms, composed with a cylinder shaped internal cavity, and adjacent a target tumor part, were developed. The phantoms were irradiated using 6 MV photon beam, with or without 0.3 T of perpendicular magnetic field. Two experimental models were developed: single beam model (SBM) to analyze central axis dose distributions and multiple beam model (MBM) to simulate a clinical case of prostate cancer with rectum. RT dose of NTIS of internal cavity and target tumor area (TTA) were measured. Results: With magnetic field applied, bending effect of dose distribution was visualized. The depth dose distribution of SBM showed 28.1% dose reduction of NTIS and little difference in dose of TTA with magnetic field. In MBM, cross-sectional dose of NTIS was reduced by 33.1% with magnetic field, while TTA dose were the same, irrespective of magnetic field. Conclusion: RT dose of mucosal lined organ, located near treatment target, could be modulated by perpendicular magnetic field.

• Journal of Radiation Protection and Research
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• v.49 no.2
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• pp.68-77
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• 2024

Background: Cone beam computed tomography (CBCT) is essential for correcting and verifying patient position before radiation therapy. However, it poses additional radiation exposure during CBCT scans. Therefore, this study aimed to evaluate radiological safety for the human body through dose assessment for CBCT. Materials and Methods: For CBCT dose assessment, the depth dose was evaluated using a cheese phantom, and the dose in the orbital area was evaluated using a human body phantom self-fabricated with a three-dimensional printer. Results and Discussion: The evaluation of radiation doses revealed maximum doses of 14.14 mGy and minimum doses of 6.12 mGy for pelvic imaging conditions. For chest imaging conditions, the maximum doses were 4.82 mGy, and the minimum doses were 2.35 mGy. Head imaging conditions showed maximum doses of 1.46 mGy and minimum doses of 0.39 mGy. The eyeball doses using a human body phantom model averaged at 2.11 mGy on the left and 2.19 mGy on the right. The depth dose ranged between 0.39 mGy and 14.14 mGy, depending on the change in depth for each imaging mode, and the average dose in the orbit area using a human body phantom was 2.15 mGy. Conclusion: Based on the experimental results, CBCT did not significantly affect the radiation dose. However, it is important to maintain a minimal radiation dose to optimize radiation protection following the as low as reasonable achievable principle.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.215-219
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• 2003

To investigate the effects of low dose gamma radiation and seed moisture content (SMC) on germination and early growth of vegetable crops, seeds of chinese cabbage (Brassica campestris L.), radish (Raphanus sativus L.), red pepper (Capcicum annuum L.), figleaf gourd (Cucurbita ficifolia Bouche) and bottle gourd (Lagenaria siceraria Standl), with different SMC were irradiated with different doses ($0{\sim}20\;Gy$) of gamma-ray by irradiator ($^{60}Co$, ca.150 TBq of capacity, AECL). Vegetable crops in which low dose gamma radiation was irradiated in seeds with different moisture content showed different response in seed germination and early growth to low dose gamma radiation. The germination rate of chinese cabbage, figleaf ground and bottle gourd irradiated with $2{\sim}8\;Gy$ showed interactive responses against relative SMC. Also, significant interactions occurred for the early growth between those factors. The stimulating effects of gamma radiation were more pronounced for hydrated seeds of chinese cabbage, radish, figleaf gourd and bottle gourd showing prominent responses with $2{\sim}10\;Gy$ irradiation, particularly for chinese cabbage and bottle gourd. These results suggest that radiation may promote germination and early growth of vegetable crops through interaction with SMC.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.19-24
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• 1971

The Korean rice, Nonglim # 6 was milled into brown rice and 92% polished one and packed with the kraft paper bags. The sample, bags were irradiated with the respective doses of 30, 50, 600 and 800 Krad and then were stored at $10^{\circ}C$ and 75% RH. Changes of fat acidity, amylase activity, viscosity of thus irradiated rice were examined during storage. The results were as follows. 1) Fat acidity increased slightly in the range of $30{\sim}50$ Krad but remarkably in the range of $600{\sim}800$ Krad. However, the rate of increase was low in comparison with the storage under the room temperature. 2) The amylase activity of both the low dose lot and the control decreased in the same rate during the storage. However the high dose lot had more remarkable decrease of the amylase activity from the beginning. 3) The viscosity by Brabender amylogram showed the slightly decreasing tendency in both the low $30{\sim}50$ Krad lot and the control lot of the polished rice powder during storage. On the other hand, the high dose lot of 600 or 800 Krad marked the similar decreasing rate but by far the lower values of the viscosity. 4) The results of the organoleptic test presented no differences between the low dose lot and the control lot, but the high dose lot and the control lot differed significantly only in the color.