• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2007년도 학술논문요약집
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• pp.133-134
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• 2007

• 한국자기학회지
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• 제17권2호
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• pp.103-107
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• 2007

본 연구에서는 고체 안에 둘러쌓인 감마선 원천핵 $^{133}Cs$를 금판(gold plate)으로 된 실린더 안에 놓았을 때 첫 여기상태인 81 keV 에너지 준위폭이 더 좁아짐을 볼 수 있었다. 이러한 결과는 에너지 준위의 수명이 연장된 것을 의미한다. 두께 0.5 mm, 길이 5 cm, 반경 1 mm의 실린더를 사용했을 때 4.2 K에서 에너지 준위폭은 6.1 %정도 좁아지는 결과를 얻었다.

• Geomechanics and Engineering
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• 제7권2호
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• pp.133-148
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• 2014

An experimental study is carried out to evaluate the performance of Lime mortar-Well graded Soil (Lime-WS) columns for the improvement of soft soils. Tests are conducted on a column of 100 mm diameter and 600 mm length surrounded by soft soil in different area ratios. Experiments are performed either with the entire area loading to evaluate the load - settlement behavior of treated grounds and only a column area loading to find the limiting axial stress of the column. A series of tests are carried out in soaking condition to investigate the influence of moisture content on the load - settlement behavior of specimens. In order to compare the behavior of Lime-WS columns with Conventional Stone (CS) columns as well as Geogrid Encased Stone (GES) columns, the behavior of these columns have been also considered in the present study. Remarkable improvement in the behavior of soft soil is observed due to the installation of Lime-WS columns and the performance of these columns is significantly enhanced by increasing the area ratio. The results show that CS columns are not suitable as a soil improvement technique for extremely soft soils and should be enhanced by encasing the column or replaced by rigid stone columns.

• 센서학회지
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• 제27권4호
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• pp.232-236
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• 2018

A radiation detection sensor was developed and characterized by combining three types of CsI(Tl) scintillators and an array-type SiPM to detect the radioactive contamination of discharged water in real time. The characterization results showed that type 3 exhibited the most desirable characteristics in response linearity (R-square: 0.97889) according to detection sensitivity and incident radiation dose. Furthermore, in terms of spectral characteristics, type 3 exhibited 16.54% at 0.356 MeV (the emission gamma ray energy of $^{133}Ba$), 10.28% at 0.511 MeV (the emission gamma ray energy of $^{22}Na$), 9.68% at 0.356 MeV (the emission gamma ray energy of $^{137}Cs$), and 2.55% and 4.80% at 1.173 MeV and 1.332 MeV (the emission gamma ray energies of $^{60}Co$), respectively. These measurements confirmed the good energy characteristics. The results were used to evaluate the spectral characteristics and energy linearity in a mixed source using type 3 with the best detection characteristics. It was confirmed that the gamma ray peaks of $^{133}Ba$, $^{22}Na$, $^{137}Cs$, and $^{60}Co$ were well resolved. Moreover, it was confirmed that R-square, which is an indicator of energy linearity, was 0.99986. This indicates a good linearity characteristic. Based on this study, further commercialization studies will contribute to measurements in real time and to the management of the contamination caused by radioactive wastewater or radioactive material leakage, which originate from facilities that use radioactive isotopes or care facilities.

• 핵의학기술
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• 제24권1호
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• pp.20-26
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• 2020

핵의학이란 방사성동위원소 추적자를 인체에 투여하여 관심장기에 대한 형태학적인 정보와 생물학적이고 기능적인 정보를 얻고 평가한다. Dose calibrator는 의료기관에서 단일 핵종의 방사능을 측정하기 위해 사용하는 장비이며, 방사성동위원소의 정확한 용량의 투여는 진단과 치료에 중요한 요인이다. 최근 정량분석을 위한 여러 시스템이 개발되고 있고 ERPF (Effective Renal Plasma Flow), GFR (Glomerular Filtration Rate) 등 정량분석이 필요한 검사에 있어서 정확한 투여 용량 및 재현성 있는 측정이 중요해지고 있다. 따라서 본 논문을 통해 Dose calibrator의 측정 깊이와 용량에 따른 선량 값의 성향을 알아보고 적절한 측정 깊이 및 용량에 대해 알아 보고자 한다. 실험에 사용한 Dose calibrator는 CRC-15R과 CRC-15βeta (Capintec, New Jersey, USA)를 사용하였다. 선원으로는 표준선원(Standard source) ¹³⁷Cs, ¹³³Ba, ⁵⁷Co를 사용하였고, 방사성 의약품은 ^99mTc-pertechnetate를 사용하였다. 표준선원은 측정 깊이만 변화하여 0 cm부터 15 cm까지 1 cm 깊이마다 15회씩 측정했고, ^99mTc-pertechnetate의 경우에는 1 mL 주사기로 표준선원과 동일한 깊이로 실험을 진행했고, 용량의 변화를 고려하여 0.1 mL, 0.3 mL, 0.5 mL, 0.7 mL, 0.9 mL로 각 깊이마다 15회씩 측정했다. 표준선원인 ¹³⁷Cs, ¹³³Ba, ⁵⁷Co의 깊이의 변화에서는 모두 깊이에 따른 선량 값의 변화가 통계적으로 유의한 차이가 있었다(p<0.05). ^99mTc-pertechnetate도 깊이에 따른 용량의 변화에서 선량 값이 모두 통계적으로 유의한 차이가 있었다(p<0.05). CRC-15R의 표준선원 비교 그래프에서 ¹³⁷Cs, ¹³³Ba, ⁵⁷Co는 Plateau를 그리기 시작한 2 cm에서 9 cm까지는 각 선원마다 비교시 통계적으로 유의한 차이가 없었다(p>0.05). CRC-15βeta의 표준선원 비교 그래프에서는 Plateau를 그리기 시작한 영역은 3 cm에서 9 cm로 통계적으로 유의한 차이가 없었다(p>0.05). ^99mTc-pertechnetate의 그래프는 0.1 mL에서 1 cm에서 7 cm, 0.3 mL와 0.5 mL에서는 0 cm에서 7 cm, 0.7 mL에서는 0 cm에서 6 cm, 0.9 mL에서는 0 cm에서 5 cm에서 통계적으로 유의한 차이가 나타나지 않았다(p>0.05). 본 연구를 통해 방사성동위원소를 환자에게 주입하거나 정도관리를 진행 시 편차가 적고 재현성을 위해 신뢰할 수 있는 구간을 확인 할 수 있었다. 높이에 따른 변화가 가장 적은 Plateau의 구간이 0.3 mL 혹은 0.5 mL의 용량으로 0 cm 에서 7 cm의 깊이에서 측정한다면, 편차를 최소한으로 줄일 수 있을 것으로 사료된다. 표준선원의 경우에는 본 연구의 결과에 따라 장비마다 Plateau의 변화가 가장 적은 구간의 깊이에서 재현성 있게 측정하는 것이 중요하다고 생각된다. 적절한 구간을 찾아서 재현성 있는 검사를 시행하면 검사의 품질향상 및 피폭선량저감 그리고 진단능을 높이는데 이바지 할 것이라고 생각된다.

• 생명과학회지
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• 제32권3호
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• pp.210-221
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• 2022

비스테로이드소염제(NSAID)와 γ-secretase 저해제(DAPT) 또는 SIRT1저해제(MHY2245)의 병용 효과를 인간 대장암(KM12) 및 간암(SNU475) 세포를 대상으로 조사한 결과, celecoxib (CCB) 및 2, 5-dimethyl celecoxib (DMC)를 포함하는 NSAID는 DAPT 또는 MHY2245와의 병용에 의하여 COX-2활성과 상관없이 NSAID의 암세포 증식 억제능이 현저히 증강되었다. DAPT와 MHY2245는 p62단백질 감소와 동시에 Notch1, CD44, CD133, octamer- binding transcription factor 4 (Oct4) 등의 다수의 종양 줄기세포 표지자 및 NICD1 발현 양을 감소시켰지만, activating transcription factor 4 (ATF4) 발현은 증강시켰다. 또한 NSAID 단독처리 보다 NSAID/DAPT 및 NSAID/MHY2245 병용 처리에 의하여 오토파지가 촉진되므로서 종양 줄기세포 표지자의 발현 및 단백질양의 감소가 가속화되고, 이에 따라 PARP 활성화 및 세포사멸이 현저히 증강 되었다. 결론적으로 NSAID/DAPT 및 NSAID/MHY2245의 병용 투여는 종양 줄기세포 표지자를 발현하는 인간 암세포의 증식 억제 및 제거에 효과적인 처리방법으로, 임상에 적용시킬 수 있는 학문적 근거로서 제공 될 수 있다.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.456-460
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• 2020

In this research, a radiation detection backpack to be used discreetly or by a wide range of users was developed using array silicon-photomultiplier (SiPM) and CsI (Tl), and its characteristics were evaluated. The R-squared value, which indicates the responsiveness of a detector based on the signal intensity, was determined to be 0.981, indicating a good linear responsivity. The energy resolutions for gamma radiation energies of Co-57 (122 keV), Ba-133 (356 keV), Cs-137 (662 keV), and Co-60 (1332 keV) were found to be 13.40, 10.50, 6.77, and 3.16%, respectively. These results confirm good energy resolution characteristics. Furthermore, in the case of mixed sources, the gamma radiation peaks were readily distinguishable, and the R-squared value for energy linearity was calculated to be 0.999, demonstrating an exceptional energy linearity. Further research based on the results of this study would enable the commercialization of lightweight SiPM-based wireless radiation detection backpacks that can be used for longer durations by replacing the photomultiplier tube, which is mainly used as the optical sensor in existing radiation detection backpacks.

• International Journal of Oral Biology
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• 제40권3호
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• pp.127-133
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• 2015

The salivary gland undergoes complex process of growth and differentiation of the branching morphogenesis of ductal system during the prenatal and early postnatal periods which are regulated by various elements in the extracellular matrix. Extracellular matrix metalloproteinase inducer (EMMPRIN) is a cell adhesion molecule. In the present study, localization and expression of EMMPRIN in development and effects of chorda-lingual denervation and cyclosporine A (CsA) treatment on the EMMPRIN expression were investigated. Immunohistochemistry, RT-PCR and Western blot were used to determine expression level. Immunohistochemistry revealed that EMMPRIN was localized specifically in the cytoplasm of ductal cells, not acini of the submandibular gland all the postnatal periods. At prenatal day 18, when the formation of ducts was not definite, no immunoreactivity was observed. Both Western blot and RT-PCR analyses revealed that EMMPRIN expression was maintained up to postnatal day 7, decreased after postnatal day 10. The EMMPRIN expression was upregulated by the surgical denervation of the chorda-lingual nerve in the gland as well as by the CsA treatment. The present study suggests that EMMPRIN is a crucial molecule for maintaining physiological functions of the salivary gland.

• Natural Product Sciences
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• 제8권4호
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• pp.133-136
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• 2002

GC-MS data on the volatile oil (CS-oil) of Chrysanthemum sibiricum herbs led to the identification of 2-methoxythioanisol, (+)-camphor, geraniol, citral, thymol, eugenol, ${\beta}-caryophyllene$ oxide, ${\beta}-caryophyllene$, ${\beta}-eudesmol$, juniper camphor together with an unknown substance using the mass spectral library and literature data. CS-oil exhibited significant cytotoxicities on HL-60 $(IC_{50}\;12.5\;{\mu}g/ml)$ cell and mild on HepG-2 cell $(IC_{50}\;102.4\;{\mu}g/ml)$, though the antioxidant ability was found not to be potent $(IC_{50}\;97.2\;{\mu}g/ml)$. However, the component eugenol showed potent antioxidant ability but mild cytotoxicity. Methyleugenol with no phenolic OH showed less potent cytotoxic and antioxidative properties than eugenol suggesting that phenolic OH plays an important role for the cytotoxic and antioxidant abilities. The oil-pretreatment prevented lipid peroxidation induced by bromobenzene in the rat. Therefore, it was demonstrated that CS-oil could be a cytotoxic agent with antioxidant properties.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.924-933
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• 2015

The correlation of the isotopic composition of uranium, plutonium, neodymium, and cesium with the burnup for high burnup pressurized water reactor fuels irradiated in nuclear power reactors has been experimentally investigated. The total burnup was determined by Nd-148 and the fractional $^{235}U$ burnup was determined by U and Pu mass spectrometric methods. The isotopic compositions of U, Pu, Nd, and Cs after their separation from the irradiated fuel samples were measured using thermal ionization mass spectrometry. The contents of these elements in the irradiated fuel were determined through an isotope dilution mass spectrometric method using $^{233}U$, $^{242}Pu$, $^{150}Nd$, and $^{133}Cs$ as spikes. The activity ratios of Cs isotopes in the fuel samples were determined using gamma-ray spectrometry. The content of each element and its isotopic compositions in the irradiated fuel were expressed by their correlation with the total and fractional burnup, burnup parameters, and the isotopic compositions of different elements. The results obtained from the experimental methods were compared with those calculated using the ORIGEN-S code.