• Korean Journal of Radiology
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• v.19 no.6
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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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• v.9 no.2
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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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• v.30 no.6
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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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• v.13 no.5
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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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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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.

• Journal of The Korean Astronomical Society
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• v.47 no.6
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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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• v.29 no.10
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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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• v.4 no.4
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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.

• Journal of the Korean earth science society
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• v.24 no.7
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• pp.604-613
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• 2003

The purpose of this study was to investigate the effect of a metastrategic activity on the development of student variable controlling abilities. Three groups of seventh graders at a middle-school in the City of Daegu participated in this study: a metastrategy activity group (ME), a problem-solving activity group (PR), and a control group (CO). The ME group was given metastrategy activity worksheets, which required students to monitor, control, and evaluate variable control strategies in a specified situation. The PR group was given problem-solving activity worksheets, which were needed to solve problems in various situations. The results were seen as follows. First, the metastrategy activity group showed better achievement (p<.05) and a longer standing effect (p<.01) than the other groups in the development of variable control ability. The problem-solving activity group was more effective than the control group (p<.05) in the development of variable controlled ability, but there was no lasting effect of the acquired ability. Second, the metastrategic activity group was more effective than the problem-solving activity group in finding fixed variables (p<.01), but not as effective in uncovering independent variables. What is not transferred to the development of the ability to find dependent variables.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.30-36
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• 1995

Until now, simple shielding is the only way to prevent harmful electromagnetic: wave from TV and monitor. In this study, we adopted special ceramics to Braun tube for radiating FIR ray. In experiment on living organisms, there was some differences between general and ceramics treated Braun tube. The chrysanthemunm the drosophila and the tadpole which were in front of ceramics treated Braun tube showed longer living activity than those in front of general tube. As a result, it is proved that the ceramics treated Braun tube offers good effects to living organisms.