• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.306-306
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• 2006

We immobilized and patterned PDA vesicles on solid substrate using micro arrayer, which have moieties to react with chemical and biological materials. Immobilized vesicle system was developed since it possesses many advantages in multiple screening, durable stability, and higher sensitivity. We applied polydiacetylene supramolecules to chemical and biological sensors for detection of ${\alpha}-cyclodextrin$ and E.coli cell selectively. This detection method could be applied as DNA chip, protein chip, and cell chip for multiple screening as well as chemical sensor by modifying the functional groups of diacetylene monomer.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1563-1570
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• 2010

To construct a highly sensitive detection system for endocrine disruptors (EDs), we have compared the activity of promoters with the n-alkane-inducible cytochrome P450 gene (ALK1), isocitrate lyase gene (ICL1), ribosomal protein S7 gene (RPS7), and the translation elongation factor-1${\alpha}$ gene (TEF1) for the heterologous gene in Yarrowia lipolytica. The promoters were introduced into the upstream of the lacZ or hERa reporter genes, respectively, and the activity was evaluated by ${\beta}$-galactosidase assay for lacZ and Western blot analysis for hER${\alpha}$. The expression analysis revealed that the ALK1 and ICL1 promoters were induced by n-decane and by EtOH, respectively. The constitutive promoter of RPS7 and TEF1 showed mostly a high level of expression in the presence of glucose and glycerol, respectively. In particular, the TEF1 promoter showed the highest ${\beta}$-galactosidase activity and a significant signal by Western blotting with the anti-estrogen receptor, compared with the other promoters. Moreover, the detection system was constructed with promoters linked to the upstream of the expression vector for the hER${\alpha}$ gene transformed into the Y. lipolytica with a chromosome-integrated lacZ reporter gene under the control of estrogen response elements (EREs). It was indicated that a combination of pTEF1p-hER${\alpha}$ and CXAU1-2XERE was the most effective system for the $E_2$-dependent induction of the ${\beta}$-galactosidase activity. This system showed the highest ${\beta}$-galactosidase activity at $10^{-6}\;M\;E_2$, and the activity could be detected at even the concentration of $10^{-10}\;M\;E_2$. As a result, we have constructed a strongly sensitive detection system with Y. lipolitica to evaluate recognized/suspected ED chemicals, such as natural/synthetic hormones, pesticides, and commercial chemicals. The results demonstrate the utility, sensitivity, and reproducibility of the system for identifying and characterizing environmental estrogens.

• Radiation Oncology Journal
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• 제22권3호
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• pp.217-224
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• 2004

목적: 저산소증은 방사선 감수성을 현저히 감소시키며, 이에 대한 적응 반응에서 hypoxia-inducible factor 1 $\alpha$(HIF-1 u$\alpha$가 중요한 역할을 하고 있다. HIF-1 $\alpha$의 발현과 방사선 감수성과의 상관 관계를 알아보고자 하였다. 대상 및 방법: 쥐의 간암 세포주인 hepalclc7 세포와 HIF-1 $\beta$가 결손되어 HIF-1 $\alpha$의 기능이 억제된 hepaIC4 세포를 사용했다 저산소 유사 물질인 desferrioxamine (DFX)을 전처치하고 6시간 뒤에 방사선조사를 하여 western blot으로 HIF-1 $\alpha$ 발현을 조사하였다. Apoptosis는 DNA 분절화, propidium iodide 핵염색, 그리고 apoptotic cell death detection ELISA kit를 이용하였다. MTT assay법으로 방사선 감수성을 측정하고 SF2$_{2}$ SF$_{8}$, 그리고 mean inactivation dose (MID)를 산출하여 통계적 분석을 하였다. 결과: Hepalclc7 세포에서는 DFX 전처치를 한 경우 방사선에 의해 HIF-1 $\alpha$의 발현이 증가했으나, hepalC4 세포 주에서는 변화가 없었다 Hepa1C4 세포의 방사선 감수성은 DFX처리에 따른 영향이 없었으나 hepalclc7 세포의 방사선 감수성은 DFX를 전처치했을 때 유의하게 감소하였다. 결론: 저산소 유사 물질인 DFX에 의해 유도된 HIF-1 $\alpha$가 쥐의 간암 세포주에서 apoptosis와 방사선 감수성을 감소시켰다 이러한 결과는 종괴내의 저산소 세포에서 방사선에 의해 HIF-1 $\alpha$가 유도되고 이로 인해 저산소 세포에서 방사선 감수성을 저하시키는 것으로 생각되었다.

• 터널과지하공간
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• 제7권4호
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• pp.334-340
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• 1997

Alpha center theory which was first proposed by Stefanescu has been proved to be effective for the detection of the location of the conductive orebody. A numerical forward modeling was conducted to verify the effectiveness of this method. Field works were carried out along the three profiles in two different areas for the purpose of finding fractured zone which might be accompanied with the presence of the groundwater. And the results were modeled by alpha center method, which was later testified by wellproven 2-dimensional finite difference inversion scheme. Field data could be successfully modeled with this alpha center algorithm, especially for the smooth-varying resistivity models. For the abrupt change of the resistivity values, the alpha center coefficients have a tendency to be negative to simulate the steep resistivity gradients. This method is quite simple and easy for the future applications. The numerical calculation can be performed very quickly with the personal computers.

• 통합자연과학논문집
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• 제8권2호
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• pp.111-116
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• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives was performed using several chiral stationary phases (CSPs) based on polysaccharide derivatives under fluorescence detection. For enantiomer separation by normal HPLC, the non-aqueous derivatization method of ${\alpha}$-amino acid esters for NBD analytes was introduced. Among the six CSPs used in this study, the performance of Chiralpak IA was superior for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Also the convenient analytical method using polysaccharide-derived CSPs developed in this study was applied to determine the optical purity of ${\alpha}$-amino acids esters. It was investigated that the enantiomeric impurity levels of 0.02-1.73% were found after determination of enantiomeric purities of several commercially available L-amino acid methyl esters. It is expected to be quite useful for enantiomer separation of other ${\alpha}$-amino acid esters as NBD derivatives by normal HPLC.

• Mass Spectrometry Letters
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• 제8권4호
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• pp.90-97
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• 2017

Androgenic anabolic steroids (AASs) are synthetic derivatives of testosterone with a common structure containing cyclopentanoperhydrophenanthrene nucleus. Their use enhances the muscle building capacity and is beneficial during performance. The AASs are one of the most abused group of substances in horse doping. Liquid chromatography tandem mass spectrometry ($LC/MS^n$) has been successfully applied to the detection of anabolic steroids in biological samples. However, the saturated hydroxysteroids viz: nandrolone, $5{\alpha}-estrane-3{\beta}$, $17{\alpha}-diol$ exhibit lower detection responses in electrospray ionisation (ESI) because of their poor ionisation efficiency. To overcome this limitation pre-column chemical derivatization has been introduced to enhance their detection responses in $LC-ESI-MS^n$ analysis. The aim of present study was to develop a sensitive method for identification and confirmation of nandrolone and its metabolite in horse urine incorporating pre-column derivatization using picolinic acid. The method consists of extraction of targeted steroid conjugates by solid phase extraction (SPE). The eluted steroid conjugates were hydrolysed by methanolysis and free steroids were recovered with liquid-liquid extraction. The resulting steroids were derivatized to form picolinoyl esters and identification was done using LC-ESI-MS/MS in positive ionization mode. The picolinated steroid adduct enhanced the detection levels in comparison to underivatized steroids.

• 한국균학회지
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• 제41권1호
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• pp.52-55
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• 2013

Phoma glomerata는 식물 잎이나 열매에 병을 일으키는 식물병원균으로 알려져 있다. 국내에서는 아직 피해사례가 없기 때문에 P. glomerata는 국내의 식물검역균으로 관리되고 있다. 본 연구는 국내에 들어오는 목재나 과일에 P. glomerata를 검출할 수 있는 방법 개발코자 수행되었다. Phoma 균주들의 translation elongation factor 1 alpha 유전자 염기서열에 기초하여 P. glomerata 특이적 PCR 프라이머를 디자인 하였고 그 특이성을 검정하였다. PCR 수행 결과 P. glomerata에서만 170 bp 크기의 밴드가 증폭되었고, 다른 비교 균주에서는 밴드가 증폭되지 않았다. 검출 감도를 평가하기 위해 기존 PCR방법과 real time PCR 방법을 이용하여 실험한 결과 최소 10 pg과 1 pg까지 각각 검출할 수 있었다. 본 연구결과는 디자인된 PCR 프라이머가 P. glomerata를 특이적으로 검출하는데 유용할 것임을 보여준다.

• 분석과학
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• 제17권4호
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• pp.302-307
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• 2004

환경시료중의 극미량의 악티늄계 동위원소들을 분석하기는 무척 어렵다. 이들 원소들은 개별 분리하는 작업이 필요하며, 알파분광법으로 분석한 어떤 핵종들은 검출감도도 높은 편이다. 이런 극미량의 악티늄계 동위원소들을 분석하기 위해 용매추출법이 결합된 TRU-Spec 이온교환수지와 음이온 교환수지를 사용하여 악티늄계 원소들을 분리한 후 알파분광법으로 검출하였다. 그리고 U과 Th의 검출한계를 낮추기 위해 중성자방사화분석법을 적용하였다. 중성자방사화분석법을 적용하기 위한 바탕물질로 고순도 V foil을 사용하여 검출감도를 10배 향상시킬 수 있었으며, 이 분석법을 표준시료인 NIST-4354, IAEA-368 퇴적물 시료에 적용한 결과 표준값과 10% 이내에서 잘 일치하였다.

• 한국환경보건학회지
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• 제36권1호
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• pp.44-51
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• 2010

This study aimed to develop analytical method for 8-isoprostanes as biomarkers for oxidative stress with LC/MS/MS technique and to apply the method for human urine samples. Analyzed compounds for urinary oxidative stress markers were 7 stereo-isomers of prostaglandins and the internal standard (iso-$PGF_{2{\alpha}}-d_4$) was used to adjust the recovery rate. The method for determining urinary iso-$PGF_{2{\alpha}}$ consisted of solid phase extraction and LC/MS/MS detection. Separation of isomers of prostaglandins completed by porous graphitic carbon column and buffer solution. Detection limits for urinary markers of oxidative stress, iso-$PGF_{2{\alpha}}$ with LC/MS/MS were 0.01 ng/ml by S/N ratio 3 and 0.028 ng/ml by calculated as to FDA method. The recovery (92.8~101.9%) and precision (8.8~20.7%) of analysis were feasible for detecting iso-$PGF_{2{\alpha}}$ in real human urine samples. We detected 4 isomers of prostaglandins in human urine samples. Mean (standard deviation) of urinary iso-$PGF_{2{\alpha}}$ concentration were 0.231 (0.117) ng/mg creatinine for smoking group and 0.154 (0.082) ng/mg creatinine for non-smoking group.

• Nuclear Engineering and Technology
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• 제28권4호
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• pp.397-404
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• 1996

The hydrogenated amorphous silicon (a-Si : H) holds good promise for radiation detection from its inherent merits over crystalline counterpart. For the application to alpha spectroscopy, the induced charge collection in a-Si : H pin detector diodes ons simulated based on a relevant non-uniform charge generation model. The simulation was peformed for the initial energy and the range of incident alpha particles, detector thickness and the operational parameters such as the applied reverse bias voltage and shaping time. From the simulation, the total charge collection was strongly affected by hole collection as expected. To get a reasonable signal generation, therefore, the hole collection should be seriously considered for detector operational parameters such as shaping time and reverse voltage etc. For the spectroscopy of alpha particle from common alpha sources, the amorphous silicon should have about 70${\mu}{\textrm}{m}$ thickness.