• Korean Journal of Radiology
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• 제19권6호
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• pp.1077-1088
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• 2018

Objective: To correlate CT parameters on detector-based dual-energy CT enterography (DECTE) with Crohn's disease activity index (CDAI) and externally validate quantitative CT parameters. Materials and Methods: Thirty-nine patients with CD were retrospectively enrolled. Two radiologists reviewed DECTE images by consensus for qualitative and quantitative CT features. CT attenuation and iodine concentration for the diseased bowel were also measured. Univariate statistical tests were used to evaluate whether there was a significant difference in CTE features between remission and active groups, on the basis of the CDAI score. Pearson's correlation test and multiple linear regression analyses were used to assess the correlation between quantitative CT parameters and CDAI. For external validation, an additional 33 consecutive patients were recruited. The correlation and concordance rate were calculated between real and estimated CDAI. Results: There were significant differences between remission and active groups in the bowel enhancement pattern, subjective degree of enhancement, mesenteric fat infiltration, comb sign, and obstruction (p < 0.05). Significant correlations were found between CDAI and quantitative CT parameters, including number of lesions (correlation coefficient, r = 0.573), bowel wall thickness (r = 0.477), iodine concentration (r = 0.744), and relative degree of enhancement (r = 0.541; p < 0.05). Iodine concentration remained the sole independent variable associated with CDAI in multivariate analysis (p = 0.001). The linear regression equation for CDAI (y) and iodine concentration (x) was y = 53.549x + 55.111. For validation patients, a significant correlation (r = 0.925; p < 0.001) and high concordance rate (87.9%, 29/33) were observed between real and estimated CDAIs. Conclusion: Iodine concentration, measured on detector-based DECTE, represents a convenient and reproducible biomarker to monitor disease activity in CD.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권2호
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• pp.118-126
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• 2004

Recombinant E.coli ACV 1003 (recA::lacZ) releasing ${\beta}$-galactosidase by a SOS regulon system, when exposed to DNA-damaging compounds, have been used to effectively monitor endocrine disruptors. Low enzyme activity of less than 10 units/mL, corresponding to a $\mu\textrm{g}$/L(ppb) range of an endocrine disruptor (tributyl tin, bisphenol A. etc.), can be rapidly determined, not by a conventional time-consuming and tedious enzyme assay, but by an alternative interferometric biosensor. Heavily boron-doped porous silicon for application as an interferometer, was fabricated by etching to form a Fabry-Perot fringe pattern, which caused a change in the refractive index of the medium including ${\beta}$-galactosidase. In order to enhance the immobilization of the porous silicon surface, a calyx crown derivative (ProLinker A) was applied, instead of a conventional biomolecular affinity method using biotin. This resulted in a denser linked formation. The change in the effective optical thickness versus ${\beta}$-galactosidase activity, showed a linear increase up to a concentration of 150 unit ${\beta}$-galactosidase/mL, unlike the sigmoidal increase pattern observed with the biotin.

• BMB Reports
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• 제30권6호
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• pp.443-447
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• 1997

We have developed a novel method for assays of spermidine and spermine synthase (aminopropyltransferase) activities using antibody against 5'-deoxy-5'-methylthioadenosine (MTA). A new assay is reported here which is based on the observation that MTA is formed as a stoichiometric by-product of the spermidine and spermine synthases reactions. In order to determine MTA, a radioimmunoassay method with sensitivity and rapidity was used. (Lee and Cho, 1997). In this assay, adenine must be added in the reaction mixture, since it effectively inhibits the action of MTA phosphorylase by which MTA is metabolized. This assay is a improvement in term of sensitivity and time saving, compared to the currently used methods. It has a level of sensitivity (100 fmol) sufficient to monitor aminopropyltransferase activities in incubations containing as little as $10{\mu}g$ protein prepared from rat tissue homogenate. The results obtained showed that this method is particularly useful for cultured cells with low enzyme concentration. Moreover, this assay has the advantage which allows studies using alternative substrates (other amines). Spermidine synthase activity was high in rat liver, but low in rat kidney. The activity of spermine synthase was in most rat tissues very low as compared to that of spermidine synthase, but was high in brain.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.773-777
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• 2003

The color of Congo red hinders the spectrometric measurements of a concentration of hydrogen peroxide and enzyme activity (Horseradish peroxidase; HRP) during enzymatic decoloring of Congo red. In this study, a method was developed to measure peroxidase activity and hydrogen peroxide concentration in the presence of Congo red. The oxidation product of HRP/hydrogen peroxide and ABTS(2,2'-azino-bis-(3-ethylbenzotriazoline-6-sulfonic acid)) formed a dark green color. The spectrum of this product showed absorption bands at 420 nm and 734 nm. When compared with the Congo red spectrum, the absorption at 734 nm of this product did not overlap with Congo red, thus making the hydrogen peroxide measurement possible even in the presence of Congo red. Kinetic study of decoloring of Congo red performed by this method showed that the decoloring reaction followed the Michaelis-Menten kinetics. Pulse feeding of hydrogen peroxide, upon depletion, significantly increased the decoloring of Congo red. This result shows that this newly developed technique can monitor, predict, and improve the enzymatic decoloring process.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.69-75
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• 2005

In order to improve the reliability of high voltage rotating machines and mold transformers, it is necessary to understand the breakdown mechanism and life assessment of the high voltage winding parts. Especially the on-line PD test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting the electrical machines, this method has been proven the major testing technology. Capacitive couplers have been the most widely used sensors for the on-line partial discharge detection in rotating machines nowadays. This paper deals with the electrical characteristics and long-term reliability of a ceramic coupler(CC), which can be easily mounted into high voltage input terminal part, has been developed and tested to continuously measure PD activity during operating condition. This paper presents electrical characteristics (dielectric loss angle, capacitance, PD inception level, breakdown voltage, and frequency response bandwidth) and long-term life test result of the developed 6.6 kV class on-line ceramic coupling sensor. It was found that this sensor had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz. Also, the voltage life of the 6.6kV class ceramic coupler was calculated over 60 years.

• 천문학회지
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• 제47권6호
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• pp.201-207
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• 2014

We report the development of solar flux receivers operating at 2.8 GHz to monitor solar radio activity. Radio waves from the sun are amplified, filtered, and then transmitted to a power meter sensor without frequency down-conversion. To measure solar flux, a calibration scheme is designed with a noise source, an ambient load, and a hot load at $100^{\circ}C$. The receiver is attached to a 1.8 m parabolic antenna in Icheon, owned by National Radio Research Agency, and observation is being conducted during day time on a daily basis. We compare the solar fluxes measured for last seven months with solar fluxes obtained by DRAO in Penticton, Canada, and by the Hiraiso solar observatory in Japan, and finally establish equations to convert observed flux to the so-called Penticton flux with an accuracy better than 3.2 sfu.

• Archives of Pharmacal Research
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• 제29권10호
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• pp.821-825
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• 2006

Two isoflavone C-glucosides, puerarin (1) and PG-3 (2), a but-2-enolide, $({\pm})-puerol$ B (3), two isoflavone O-glucosides, daidzin (4) and genistin (5), and three pterocarpans, (-)-medicarpin (6), (-)-glycinol (7) and (-)-tuberosin (8), were isolated from a MeOH extract of the roots of Pueraria Iobata, using an in vitro bioassay based on the inhibition of the formation of advanced glycation end products (AGEs) to monitor chromatographic fractionation. The structures of 1-8 were determined by spectroscopic data interpretation, particularly by 1D- and 2D-NMR studies, and by comparison of these data with values in the literature. All of the isolates (1-8) were evaluated for their inhibitory activity on AGEs formation in vitro. Of these, puerarin (1), PG-3 (2), and $({\pm})-puerol$ B (3) exhibited more potent inhibitory activity than the positive control aminoguanidine.

• Animal cells and systems
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• 제4권4호
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• pp.341-345
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• 2000

It has been very difficult to develop and evaluate efficient fish vaccines because fish immune cells have not been properly characterized. In this study, we investigated the cell-mediated immunological properties of B- and T-like cells in Nile tilapia (Oreochromis nilotica). Surface immunoglobulin negative ($slg^{-}$) cell population proliferated in response to mammalian T-cell mitogens PHA and Con A, while surface immunoglobulin positive ($slg^{+}$) cells responded to the B-cell mitogen LPS. The slg$^{[-10]}$ cells from hemocyanin (HC)-immunized Tilapia, compared to the non-immunized control, reacted more to PHA than to Con A. Unexpectedly, antigen (Ag)-specific response was observed in both $slg^{-}$ and $slg^{-}$cells. Regardless of HC immunization, whole leukocytes from 8 head kidney of fish showed natural killer (NK)cell activity. Especially, NK cell activity was much higher in slg$^{[-10]}$ cells than in slg$^{+}$cells, indicating the possibility that fish NK cells were not at least associated with slg$^{+}$ cell population and not activated by Ag. Further understanding of functional fish immune cells will help to evaluate and develop effective vaccines for fishes and to monitor the course of therapy In infected fishes.hes.

• 한국지구과학회지
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• 제24권7호
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• pp.604-613
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• 2003

이 연구의 목적은 메타전략 활동이 중학교 1학년 학생들의 변인통제 능력 향상에 효과가 있는지를 조사하는 것이었다. 이를 위해 대구광역시내 1개 중학교 1학년 3학급을 각각 메타전략 활동집단, 문제풀이 활동집단 및 통제집단으로 선정하였다. 처치활동으로 메타전략 활동집단에게는 매회 15분씩 총 4회에 걸쳐 어느 한 특정 상황에서 변인통제전략에 대한 컨트롤, 모니터 및 평가 등의 활동이 요구되는 자료를 투입하였다. 문제풀이 활동집단에게는 메타전략 활동집단과 같은 방법으로 활동자료를 투입하였으나 그 내용은 다양한 상황하에서 여러 가지 변인통제 문제들을 해결하는 활동으로 구성되었다. 이 연구의 결과는 다음과 같다. 첫째, 메타전략 활동집단은 문제풀이 활동집단 및 통제집단보다 변인통제 능력 향상에 효과적이며(p<.05) , 그 효과는 지속적이었다(p<.01). 문제풀이 활동집단의 경우, 통제집단보다 효과는 있었으나(p<.05) 지속 효과는 없었다. 둘째, 변인통제 능력의 요소별 발달 정도를 집단간 비교 분석 결과, 메타전략 활동집단이 문제풀이 활동집단보다 고정변인 찾기 능력에서 통계적으로 유의미한 차이를 보인 반면(p<.01), 독립변인 찾기 능력에서는 통계적으로 유의미한 차이가 없었으며, 종속변인 찾기 능력 발달로의 전이의 효과는 없었다. 따라서 이상의 연구 결과를 종합해 볼 때, 과학탐구능력 중의 변인통제 능력을 향상시키기 위해서는 다양한 문제를 해결하도록 하는 활동 못지 않게 한 문제에 대해 깊이 생각해보는 메타전략 활동이 효과가 있음을 알 수 있었다.

• 한국조명전기설비학회지:조명전기설비
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• 제9권1호
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• pp.30-36
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• 1995

지금까지 TV와 모니터에서 발생되는 유해한 전자파와 정전기에 대해서는 단순한 차폐방법으로만 대응해 왔다. 본 연구에서는 이와는 달리 생체에 유익한 특성을 역으로 제공하는 방법에 착상하여 생체에 유익한 것으로 알려진 원적외선이 방사되도록 특수세라믹스를 브라운관에서 적용하고 이를 이용하여 생체실험을 한 결과, 일반 TV와 모니터에서보다 국화는 약 1.5배, 초파리와 올챙이는 약 2배 향상된 생명력이 나타났다. 결과적으로 원적외선이 방사되는 특수처리한 브라운관이 생체유익효과를 제공한다는 사실이 입증되었다.