• Environmental Analysis Health and Toxicology
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• 제25권2호
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• pp.111-120
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• 2010

DEPs (diesel exhaust particles) like any other particles can be also inhaled into lung to participate in a damaging reaction to the organ. Possible damages might be apoptosis and inflammatory responses to the cells in respiratory track. The aim of this study was cytotoxicity evaluation of DEPs from five in-use diesel vehicles using a murine macrophage cell (RAW 254.7). We found that most DEPs have a considerable cytotoxicity compared to the control and SRM 2975. When measured by MTT assay and extents of apoptosis, DEPs of two highmileage vehicles had higher toxicity than those of the other three low-mileage vehicles tested. Although mRNA expression level of TNF-${\alpha$ somewhat explains the trend of cytotoxicity and apoptosis, that of IL-1$\beta$ did not. Correlation studies among the extents of MTT assay, apoptosis, and TNF-$\alpha$ expression showed that the extents between apoptosis and TNF-$\alpha$ expression was most highly correlated (r=0.96). These results suggest that cytotoxicity of various DEPs could be compared easily by measuring the extent of apoptosis or TNF-$\alpha$ expression by DEPs.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.821-827
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• 2014

An isotope dilution liquid chromatography tandem mass spectrometry (ID LC-MS/MS) method has been developed and applied to the determination of arsenobetaine (AsB, ${(CH_3)_3}^+AsCH_2COO^-$) from oyster candidate certified reference material (CRM). The exact matching isotope dilution approach was adopted for accurate determination of AsB using $^{13}C_2$-labeled AsB as an internal standard. Efficiencies of different AsB extraction methods were evaluated using a codfish reference material and a simple sonication method was selected as the method of choice for the certification of the oyster candidate CRM. The hydrophilic interaction liquid chromatography (HILIC) combined with electrospray ionization tandem mass spectrometry (ESI/MS/MS) in selected reaction monitoring (SRM) mode was optimized for adequate chromatographic retention and robust quantification of AsB from codfish and oyster samples. By analyzing 12 subsamples taken from each 12 bottles systematically selected from the whole oyster CRM batch, the certified value of AsB was determined as $6.60mg{\cdot}kg^{-1}{\pm}0.31mg{\cdot}kg^{-1}$ and it showed excellent between-bottle homogeneity of less than 0.42%, which is represented by relative standard deviation of 12 bottles from the CRM batch. The major source of uncertainty was the certified value of the AsB standard solution.

• 한국항행학회논문지
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• 제13권6호
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• pp.957-963
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• 2009

본 논문은 스토리지 디바이스에 대한 자원관리 시스템의 설계에 관한 것이다. 컴퓨팅 환경의 변화와 복잡화에 따라 자원에 대한 효율적인 관리방안으로 제안되고 있는 표준관리응용프로그램을 설계하기 위해서 객체지향 모델링 기술에 바탕을 둔 공통정보모델을 사용하여 관리객체에 대한 모델링 과정을 수행하였다. 표준화된 관리응용프로그램 구현 방법을 사용하여 사용자에게 시각적인 특성을 제공할 수 있도록 GUI인터페이스를 구현하였으며 시스템의 구성 요소를 자동으로 검색, 관리하고 각 구성 요소의 상태 정보를 주의/경고/긴급의 3단계로 분류하여 사용자에게 제공하였다. 또한 다양한 구성 요소의 운용을 위한 설정기능을 제공하는 관리응용시스템을 구현하였다.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.295-302
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• 2009

The flow in the draft tube cone of Francis turbines operated at partial discharge is a complex hydrodynamic phenomenon where an incoming steady axisymmetric swirling flow evolves into a three-dimensional unsteady flow field with precessing helical vortex (also called vortex rope) and associated pressure fluctuations. The paper addresses the following fundamental question: is it possible to compute the circumferentially averaged flow field induced by the precessing vortex rope by using an axisymmetric turbulent swirling flow model? In other words, instead of averaging the measured or computed 3D velocity and pressure fields we would like to solve directly the circumferentially averaged governing equations. As a result, one could use a 2D axi-symmetric model instead of the full 3D flow simulation, with huge savings in both computing time and resources. In order to answer this question we first compute the axisymmetric turbulent swirling flow using available solvers by introducing a stagnant region model (SRM), essentially enforcing a unidirectional circumferentially averaged meridian flow as suggested by the experimental data. Numerical results obtained with both models are compared against measured axial and circumferential velocity profiles, as well as for the vortex rope location. Although the circumferentially averaged flow field cannot capture the unsteadiness of the 3D flow, it can be reliably used for further stability analysis, as well as for assessing and optimizing various techniques to stabilize the swirling flow. In particular, the methodology presented and validated in this paper is particularly useful in optimizing the blade design in order to reduce the stagnant region extent, thus mitigating the vortex rope and expending the operating range for Francis turbines.

• Nuclear Engineering and Technology
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• 제32권5호
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• pp.477-484
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• 2000

To estimate the degree of intake of $^{238}$ U and $^{232}$ Th through daily diet, a Korean mixed diet sample was prepared after the investigation of the amount of consumption of the daily diet which corresponds to the age of 20 to 60 years. For the analysis of U and Th, the RNAA method was applied. Two standard reference materials were used for quality control and assurance and the analytical results were compared with a certified value. The determination of U and Th in the Korean mixed diet sample was carried out under the same analytical conditions and procedures with SRM. It is found that the concentration of U and Th in a Korean mixed diet was about 35.4 ppb and 3.4 ppb. From these results, the daily intake of $^{238}$ U and $^{232}$ Th by diet is evaluated to be 6.98 and 0.67 $\mu\textrm{g}$ per day, respectively. Radioactivities related to the intake of $^{238}$ U and $^{232}$ Th were estimated to be about 86 mBq and 27 mBq per person per day and the annual dose equivalents from $^{238}$ U and $^{232}$ Th revealed as 3.18 $\mu$Sv and 0.29 $\mu$Sv per person, respectively.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.645-650
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• 2017

This technical note demonstrates the feasibility of using laser ablation inductively coupled plasma mass spectrometry for the characterization of U-7Mo/Ale5Si dispersion fuel. Our measurements show 5.0% Relative Standard Deviation (RSD) for the reproducibility of measured $^{98}Mo/^{238}U$ ratios in fuel particles from spot analysis, and 3.4% RSD for $^{98}Mo/^{238}U$ ratios in a NIST-SRM 612 glass standard. Line scanning allows for the distinction of U-7Mo fuel particles from the Al-5Si matrix. Each mass spectrum peak indicates the presence of U-7Mo fuel particles, and the time width of each peak corresponds to the size of that fuel particle. The size of the fuel particles is estimated from the time width of the mass spectrum peak for $^{98}Mo$ by considering the scan rate used during the line scan. This preliminary application clearly demonstrates that laser ablation inductively coupled plasma mass spectrometry can directly identify isotope ratios and sizes of the fuel particles in U-Mo/Al dispersion fuel. Once optimized further, this instrument will be a powerful tool for investigating irradiated dispersion fuels in terms of fission product distributions in fuel matrices, and the changes in fuel particle size or shape after irradiation.

• 통합자연과학논문집
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• 제16권4호
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• pp.123-131
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• 2023

Breast cancer continues to pose a substantial worldwide health challenge, thereby requiring the development of innovative strategies to discover new therapeutic interventions. Signal Transducer and Activator of Transcription 3 (STAT-3) has been identified as a significant factor in the development of several types of cancer, including breast cancer. This is primarily attributed to its diverse functions in promoting tumour formation and conferring resistance to therapeutic interventions. This study presents an in silico drug repositioning approach that focuses on identifying specific inhibitors of STAT-3 for the purpose of treating breast cancer. We initially examined the structural and functional attributes of STAT-3, thereby elucidating its crucial involvement in cellular signalling cascades. A comprehensive virtual screening was performed on a diverse collection of drugs that have been approved by the FDA from zinc15 database. Various computational techniques, including molecular docking, cross docking, and cDFT analysis, were utilised in order to prioritise potential candidates. This prioritisation was based on their predicted binding energies and outer molecular orbital reactivity. The findings of our study have unveiled a Dihydroergotamine and Paritaprevir that have been approved by the FDA and exhibit considerable promise as selective inhibitors of STAT-3. In conclusion, the utilisation of our in silico drug repositioning approach presents a prompt and economically efficient method for the identification of potential compounds that warrant subsequent experimental validation as selective STAT-3 inhibitors in the context of breast cancer. The present study highlights the considerable potential of employing computational strategies to expedite the drug discovery process. Moreover, it provides valuable insights into novel avenues for targeted therapeutic interventions in the context of breast cancer treatment.

• 한국식품위생안전성학회지
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• 제36권1호
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• pp.34-41
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• 2021

본 연구는 조제유류 중 지방산에 대해 최신 분석법을 마련하고자 수행하였다. 조제유류 중 지방산 함량 분석을 위해 GC를 이용한 분석법을 확립하고 시중에 유통 중인 제품을 대상으로 적용성을 검토하였다. 분석법 검증은 특이성, 직선성, 검출한계 및 정량한계, 정확성, 정밀성에 대해 수행되었다. Linoleic acid 및 α-linolenic acid의 0.1-5 mg/mL 농도범위에서 R2=0.999 이상의 우수한 직선성을 확인할 수 있었다. Linoleic acid 및 α-linolenic acid의 LOD는 각각 0.06 mg/mL, 0.01 mg/mL, LOQ는 각각 0.16 mg/mL, 0.03 mg/mL였다. 표준인증물질 분석을 통해 정확성을 검토하였으며, linoleic acid 및 α-linolenic acid의 회수율은 각각 100.8%와 101.1%로 확인하였다. 정밀성을 검토한 결과 시료 채취량에 따른 반복성은 linoleic acid 1.4-2.9%, α-linolenic acid 1.1-2.7%이었고, 실험실간 재현성은 각각 2.8%, 1.5%임을 확인하였다. 본 연구에서 확립된 분석법을 적용하여 국내 유통 중인 조제유류 및 조제식 제품 12건에 대해 적용성 검토를 실시한 결과 전체 시료에서 분석이 용이하였으며, 모두 기준·규격에 적합함을 확인하였다. 본 결과로부터 확립된 GC를 이용한 분석법은 조제유류 중 지방산 함량을 확인하기에 적합함을 확인하였으며 국내 식품 영양성분의 관리 기반을 강화하는데 기여할 것으로 사료된다.

• 분석과학
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• 제14권2호
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• pp.115-122
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• 2001

우리나라 해안에 인접한 "K"지역 병원에서 구한 44명의 혈액에서 유기주석화합물인 mono-butyltin(MBT), dibutyltin(DBT) 그리고 tributyltin(TBT)을 불꽃광도검출기가 부착한 가스크로마토그라프로 분석하였다. 본 연구의 목적은 일부 주민의 혈액을 대상으로 MBT, DBT, TBT에 대한 분석방법과 농도를 고찰하는 것이다. 본 연구에서 이용한 분석방법에 대한 검출한계(method detection limit, MDL)는 MBT 3.67, DBT 0.91, TBT는 1.09ng Sn/g 습중량 기준으로 나타났다. 또한 일본 국립환경연구소가 제조한 농어중의 $1.3{\mu}g/g$ TBT as chloride의 농도가 가진 표준물질(standard reference material)을 분석한 결과 공인값과 잘 일치하였다. 혈액 중에서 검출된 농도의 범위는 MBT가 3.69-7.93ng Sn/g, DBT 1.15-5.41ng Sn/g이었고, TBT는 검출한계 미만 및 미검출이었다. 혈액중에서 검출된 MBT 및 DBT의 흡수와 축적은 사람들이 유기주석화합물이 생체축적된 수산물의 섭취, 각종 플라스틱류 사용 등에 원인이 있을 것으로 사료된다. 혈액중 유기주석화합물이 인체로 흡수되는 내재용량(internal dose)을 평가할 수 있는 지표서의 신뢰성에 관한 연구가 계속해서 진행되어야 할 것으로 판단된다.

• 분석과학
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• 제16권2호
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• pp.152-158
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• 2003

본 연구는 인체의 골중 납 농도를 측정하는데 필요한 시료 전처리법과 기기 분석법을 평가하기 위하여 수행되었다. 절단한 인간 사체 다리의 뼈를 상온에서의 산 분해법과 마이크로웨이브 분해법 (microwave oven method)을이용하여 납을 추출하였으며, 유도결합 플라즈마 질량분석법 (ICP-MS)과 흑연로 원자 흡수 분광 광도법 (GF-AAS)으로 납 농도를 측정하였다. 표준시료를 이용하여 회수율을 조사한 결과, 산분해 후 ICP-MS로 측정한 경우 높은 회수율을 보였으나, 산분해 후 GF-AAS로 측정한 것은 표준 농도보다 낮은 값을 보였으며, 마이크로웨이브 분해한 경우는 두 측정기기 모두 표준 농도보다 높은 값을 보였다. 뼈 시료의 경우, 산분해 후 ICP-MS로 측정한 납 농도는 GF-AAS의 값과 높은 상관성을 보였으나 (상관계수 = 0.983), GF-AAS가 ICP-MS보다 계통적으로 높은 값을 측정하였다. 마이크로웨이브 분해 역시 두 분석방법이 높은 상관성을 보였으나 (상관계수 = 0.950), 대체로 산분해에 의한 값보다 높은 농도를 보였다. 결론적으로, 상온에서 질산으로 분해 후 ICP-MS를 이용하여 측정한 것이 골중 납 농도를 결정하는데 편이성과 정확성 면에서 가장 효율적인 방법으로 보인다.