• Journal of radiological science and technology
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• v.40 no.4
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• pp.595-603
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• 2017

The study is to produced a brain phantom simulating corpus striatum, which can evaluate the progression of parkinson's disease, to investigate possibility of reducing the brain exposure dose to CT while maintaining optimal image quality during PET-CT examinations. CT scans were performed by varying tube voltage (100, 120 kVp) and tube current (80, 140, 200 mAs) with $^{18}F$ FP-CIT injected into the phantom's hot sphere and background (radioactivity ratio 3:1)(reference condition; 120 kVp, 140 mAs). Estimated effective dose was calculated by using conversion factor according to each condition, and image quality was evaluated by setting SNR and CRChot image evaluation factors. Experimental results showed that the predicted effective dose below the CT imaging reference condition was reduced by at least 10% and by up to 60%, and the predicted effective dose beyond the reference condition was increased by 40%. In addition, there was no significant difference between SNR and CRChot of PET images, and it was confirmed that brain dose decreased with decrease of tube voltage and tube current. At the same time, there was no significant change in the quality of the image in terms of SNR and CRChot despite the change in scan conditions. This fact suggests that the quality of the images acquired under the existing dose conditions can be obtained even at low dose conditions and it is expected that it will be possible to use the brain PET-CT scan as a basic data for the research on reduction of dose and improvement of image quality.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.217-227
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• 2021

In this study, Korean-cultivated Houttuynia cordata Thunb. (HC) was extracted anti-inflammatory effects of extracts were compared in order to confirm the possibility of natural cosmetics as a raw material. HPLC pattern analysis, cell viability assay, total phenolic contents, ABTS/DPPH radical scavenging analysis, measurement of ROS production, griess reagent assay, and luminex technique. The content of quercetin was higher in fresh Houttuynia cordata (HC-F) than in dried Houttuynia cordata (HC-D). Also, content of HC extracts shows a difference in the content of the two representative compounds (polyphenol and flavonoid) according to the stored differently. ROS production showed higher inhibitory rates at HC-F. The anti-inflammatory activity of HC-D was shown higher than that of HC-F. But, in the measurement of the reduction in inflammatory cytokines, IL-1β showed that HC-D had a relatively high reduction effect, and IL-6 and TNF-α showed a high reduction effect. And these results will be a basis for the development of cosmetology in skin care and improvement of skin problem.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.383-388
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• 2004

This paper presents the aerodynamic coefficient modeling with a new model structure explored by Least Squares using Modulating Function Technique (LS/MFT) for an F-16XL airplane using wind tunnel data supplied by NASA/LRC. A new model structure for aerodynamic coefficient was proposed, one that considered all possible combination terms of angle of attack ${\alpha}$(t) and ${\alpha}$(t) given number of harmonics K, and was compared with Pearson's model, which has the same number of parameters as the new model. Our new model harmonic results show better agreement with the physical data than Pearson's model. The number of harmonics in the model was extended to 6 and its parameters were estimated by LS/MFT. The model output of lift coefficient with K=6 correspond reasonably well with the physical data. In particular, the estimation performances of four aerodynamic coefficients were greatly improved at high frequency by considering all harmonics included in the input${\alpha}$(t), and by using the new model. In addition, the importance of each parameter in the model was analyzed by parameter reduction errors. Moreover, the estimation of three parameters, i.e., amplitude, phase and frequency, for a pure sinusoid and a finite sum of sinusoids- using LS/MFT is investigated.

• Journal of Korean Academy of Nursing
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• v.36 no.6
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• pp.992-1001
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• 2006

Purpose: This study was done to provide data for a nursing intervention to alleviate newborn pain clinically by investigating the effect of oral glucose. Methods: Subjects were newborns hospitalized in the nursery. Informed consent was obtained from parents of 60 newborns. A heel stick was carried out for a test on 3 groups; the experimental, placebo, and control group. The Neonatal infant pain scale(NIPS), respiration rate, heart rate, peripheral oxygen partial pressure($SpO_2$), and crying duration were measured to assess pain reaction. All neonatal behaviors were recorded on videotape. Results: There were significant differences in pain behavior during stimulus(F=4.195, p=.020), pain behavior immediately after blood-sampling (F=4.114, p=.021), and pain behavior 3 minutes after that (F=3.630, p=.033). However, there were no significant differences in heart rate, respiration rate, peripheral oxygen partial pressure or crying duration after the heel stick among the groups. Conclusions: Oral administration of glucose before a heel stick caused the reduction of neonatal pain behavior, which means that it has an effect of pain relief.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.383-386
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• 2005

Low frequency heavy-weight impact noise is the most irritating noise in Korean high-rise reinforced concrete apartment buildings. This low frequency noise is generated by foot traffic due to the fact that Koreans do not wear shoes at home. The transmission of the noise is facilitated by a load bearing wall structural system without beams and columns which is used in these buildings. In order to control low frequency heavy-weight impact noise, floating floors using isolation materials such as glass-wool mat and poly-urethane mat are used. However, it was difficult to control low frequency heavy-weight impact sound using isolation material. In this study, reinforcement of concrete slab using beams and plate was conducted. Using the FEM analysis, the effect of concrete slab reinforcement using FRP(fiber-glass reinforced plastic) on the bang machine impact vibration acceleration level and sound were conducted at the standard floor impact sound test building. The $3{\sim}4dB$ floor impact vibration acceleration level and impact sound pressure level were reduced and the natural frequency of slabs were changed.

• BMB Reports
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• v.34 no.1
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• pp.90-94
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• 2001

The mutagenic activity of chitosan oligosaccharide and its antimutagenic effect against 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) were investigated using the Salmonella/Ames test. No mutagenic activity was found in the Salmonella typhimurium strains TA 98 and TA 100, either with or without S9 activation. In contrast, chitosan oligosaccharide showed an inhibitory effect on the mutagenic activity of the cooked food mutagen, MeIQx, in the presence of S9. The influence of chitosan oligosaccharide on the genotoxicity of MeIQx was examined using a host-mediated assay in mice. The oligosaccharide was administered for 14 consecutive days (intragastric application at doses of 0.1 or 0.5 g/kg body wt) to mice. S. typhimurium TA 98 was given intravenously before an oral dose of MeIQx (4.5 mg/kg body wt.). The number of $his^+$ revertants were determined from the Ever of mice. The intragastric application of oligosaccharide led to a 47% reduction in the number of mutants induced by MeIQx (p<0.05). These results suggested that chitosan oligosaccharide had antimutagenic properties against MeIQx in vitro and in vivo.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.197-201
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• 2010

$SF_6$ gas would be used in power transformer, GIS (Gas insulated switchgear) and so on because of its electrically superior insulation and chemically stable structure. Recently, the reduction of $SF_6$ is required to avoid global warming and the researches on the dilution of $SF_6$ with other gases have been carried out. $SF_6$ mixture gases with $N_2$ and $C_xF_y$ have drawn attention to the synergy effect. However, in order to understand the mechanism of the synergy effect, it is important to analyze and evaluate properties of mixture gases quantitatively. In this paper, we investigated the mechanism of synergy effect from electron collision processes and electron energy distribution by solving Boltzmann equation with propagator method. Three kinds of gases for dilution of $SF_6$ ($SF_6/N_2$, $SF_6/CF$4 and $SF_6/C_4F_8$) are considered in this simulation. On the properties of $SF_6/N_2$ mixture gas, the variation of reduced electric field was shown highly within 0%~40% mixtures of $SF_6$. And the more low-level electron energy has been distributed, the higher insulation capability has appeared.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1833-1840
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• 2013

Metastasis is one of the hallmarks of malignant neoplasms and is the leading cause of death in many cancer patients. A major challenge in cancer treatment is to find better ways to specifically target tumor metastasis. In this study, the anti-metastatic potential of the methanolic extract of Rhizophora apiculata (R.apiculata) was evaluated using the B16F-10 melanoma induced lung metastasis model in C57BL/6 mice. Metastasis was induced in C57BL/6 mice by injecting highly metastatic B16F-10 melanoma cells through the lateral tail vein. Simultaneous treatment with R.apiculata extract (10 mg/kg b.wt (intraperitoneal) significantly (p<0.01) inhibited pulmonary tumor nodule formation (41.1 %) and also increased the life span (survival rate) 107.3 % of metastatic tumor bearing animals. The administration of R.apiculata extract significantly (p<0.01) reduced biochemical parameters such as lung collagen hydroxyproline, hexosamine, uronic acid content, serum nitric oxide (NO), ${\gamma}$-glutamyl transpeptidase (GGT) and sialic acid levels when compared to metastasis controls. These results correlated with lung histopathology analysis of R.apiculata extract treated mice showing reduction in lung metastasis and tumor masses. Taken together, our findings support that R.apiculata extract could be used as a potential anti-metastasis agent against lung cancer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1078-1084
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• 2006

Impurity contamination induced by $CF_4\;and\;HBr/Cl_2/O_2$ plasma etching on Si surface was examined by using surface spectroscopes. XPS(x-ray photoelectron spectroscopy) surface analysis showed that F of 0.4 at % exists in the surface layer in the form of Si-F bonding but Br and Cl are below the detection limit $(0.1{\sim}1.0%)$ of the spectroscope. Static-SIMS(secondary ion mass spectrometry) surface analysis showed that the etched Si surface was contaminated with etching gas elements such as H, F, Cl and Br, and they existed to the depth of about $20{\sim}40nm$. The etched Si surface was treated with three different methods that were HF dip, thermal oxidation followed by HF dip and oxygen-plasma oxidation followed by HF dip. They showed an effect in reducing the impurity contamination and the oxygen-plasma oxidation followed by HF dipping method appears to be a little bit more effective.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.6
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• pp.28-36
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• 1998

We have proposed a new non-inverting SOI buffer circuit for the high speed operation at low supply voltage. The body biases of main MOS devices in the proposed circuit are controlled dynamically via subsidiary MOS device connected efficiently to the body terminal. We showed current derivability of the body controlled devices obtained by device simulation and compared with that of conventional SOI devices. Delay time characteristics of the buffer circuit were analyzed by SPICE simulation and compared with those of conventional SOI CMOS buffer circuits. Delay time reduction of the SOI buffer over conventional SOI CMOS buffer with same area is about 36 % at $V_{S}$=1.2 V and $C_{L}$=2 pF. pF.