• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.33-39
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• 2001

To develop a method for separation process using Sep-pak $C_18$, simultaneous and systematic analysis of 8 permitted and 11 non-permitted synthetic food colors in Korea, optimization of analysis conditions for reverse phase ion-pair high performance liquid chromatography was carried out. For the best result of Sep-pak $C_18$ separation the pH of color standard mixture solution was $5{\sim}6$ and 0.1% HCl-methanol solution were set as eluent. The colors eluated from Sep-pak $C_18$ cartridge were determined and confirmed by high performance liquid chromatography with a photodiode array detector at 420 nm for yellow colors type, at 520 nm for red colors type, at 600 nm for blue and green colors type and at 254 nm for mixed colors. Conditions for HPLC analysis were as follows: column, Symmetry $C_18$ (5 m, 3.9 mm $i.d.{\times}150\;mm$); mobile phase, 0.025 M ammonium acetate (containing 0.01 M tetrabutylammonium bromide) : acetonitrile : methanol (65 : 25 : 10) and 0.025 M ammonium acetate(containing 0.01 M tetrabutylammonium bromide) : acetonitrile : methanol (40 : 50 : 10); flow rate, 1 mL/min. It takes 35 minutes for simultaneaus analysis and 18 minutes for systematic analysis. The detection limits range of each colors were $0.01{\sim}0.05\;{\mu}g/g$.

• Tuberculosis and Respiratory Diseases
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• v.39 no.6
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• pp.474-483
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• 1992

Background: Regardless of its causes, acute lung injury is characterized pathophysiologically by increased pulmonary arterial pressure and the protein-rich edema. Many inflammatory mediators are known to be involved in the pathogenesis of acute lung injury, including oxygen free radicals (OFR). But the changes in pulmonary capillary pressure in the OFR-induced acute lung injury is not clear. While the pulmonary edema characterized by the movement of fluid and solutes is dependent on the pressure gradient and the alveolar-capillary permeability, the role of pulmonary capillary pressure in the development of pulmonary edema is also not well understood. Method: Male Sprague-Dawley rats were divided into 5 groups: normal control (n=5), xanthine/xanthine oxidase (X/XO)-treated group (n=7), catalase-pretreated group (n=5), papaverine-pretreated group (n=7), and indomethacin-pretreated group (n=5). In isolated perfused rat lungs, the sequential changes in pulmonary arterial pressure, pulmonary capillary pressure by double occlusion method, and lung weight as a parameter of pulmonary edema were determined. Results: Pulmonary arterial pressure and pulmonary capillary pressure were increased by X/XO. This increase was significantly attenuated by catalase and papaverine, but indomethacin did not prevent the X/XO-induced increase. Lung weight gain was also observed by X/XO perfusion. It was prevented by catalase. Papaverine did not completely block the increase, but significantly delayed the onset. Indomethacin had no effect on the increase in lung weight. Conclusion: These data suggest that increased pulmonary capillary pressure by OFR may aggravate pulmonary edema in the presence of increased alveolar-capillary permeability and this may not be mediated by cyclooxygenase metabolites.

• Tuberculosis and Respiratory Diseases
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• v.42 no.5
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• pp.703-712
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• 1995

Background: Peripheral blood monocytes are important immune effector cells that play a fundamental role in cellular immunity. In addition to their antigen-presenting and phagocytic activities, monocytes/macrophage produce a vast array of regulatory and chemotactic cytokines. Interleukin-8(IL-8), a potent neutrophil-activating and chemotactic peptide, is produced in large quantities by mononuclear phagocytes and may be an important mediator of local and systemic inflammation. Overexpression by IL-8 of such inflammation may be an important step of tissue injury frequently seen in inflammatory reaction. So it could be hypothesized that the agents which block the production of IL-8 can decrease the inflammatory reaction and tissue injury. To evaluate this, we described the effect of Dexamethasone, $PGE_2$, Indomethacin and Interferon-$\gamma$(IFN-$\gamma$) on IL-8 mRNA and protein expression from LPS-stimulated human peripheral blood monocytes(PBMC). Method: PBMC was isolated from healthy volunteers. To evaluate the effect of Dexamethasone, $PGE_2$ & Indomethacin, these drug were treated for 1 hour before and after LPS stimulation and IFN-$\gamma$ was only treated I hour before the LPS stimulation. Northern blot analysis for IL-8 mRNA and ELISA for immunoreactive IL-8 protein in culture supernatant were performed. We repeated above experiment three times for Northern blot analysis and two times for ELISA and got the same result. Results: 1) Pre- and post-treatment of Dexamethasone suppressed both the LPS stimulated IL-8 mRNA expression and IL-8 protein release in PBMC. 2) IFN-$\gamma$ pre-treatment suppressed the IL-8 mRNA expression and IL-8 protein release in unstimulated cells. 3) In LPS stimulated cells, IFN-$\gamma$ suppressed the IL-8 mRNA expression but IL-8 protein release suppression was not observed. 4) $PGE_2$ and Indomethacin exert no effect on the LPS-stimulated IL-8 mRNA and protein expression in concentration used in this experiment ($PGE_2;10^{-6}M$, Indomethacin; $10{\mu}M$). Conclusion: One of the mechanism of antiinflammatory action of Dexamethasone can be explained by the suppressing effect of IL-8 production in some extent and by this antiinflammatory effect, dexamethasone can be used to suppress local and systemic inflammation mediated by IL-8.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.779-793
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• 2023

Intensive and long-term aquaculture activities in Korea have generated considerable amounts of organic matter, deteriorating the sedimentary environment and ecosystem. The Korean government enacted the Fishery Management Act to preserve and manage the environment of fish farms. Based on this, a fisheries environment assessment has been conducted on fish cage farms since 2014, necessitating the development of a scientific and objective evaluation method suitable for the domestic environment. Therefore, a benthic health index (BHI) was developed using the relationship between benthic polychaete communities and organic matter, a major source of pollution in fish farms. In this study, the development process and calculation method of the BHI have been introduced. The BHI was calculated by classifying 225 species of polychaetes appearing in domestic coastal and aquaculture areas into four groups by linking the concentration gradient of the total organic carbon in the sediment and the distributional characteristics of each species and assigning differential weights to each group. Using BHI, the benthic fauna communities were assigned to one of the four ecological classes (Grade 1: Normal, Grade 2: Slightly polluted, Grade 3: Moderately polluted, and Grade 4: Heavily polluted). The application of the developed index in the field enabled effective evaluation of the Korean environment, being relatively more accurate and less affected by the season compared with the existing evaluation methods like the diversity index or AZTI's Marine Biotic Index developed overseas. In addition, using BHI will be useful in the environmental management of fish farms, as the environment can be graded in quantified figures.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.135-149
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• 2020

Artificial intelligences are changing world. Financial market is also not an exception. Robo-Advisor is actively being developed, making up the weakness of traditional asset allocation methods and replacing the parts that are difficult for the traditional methods. It makes automated investment decisions with artificial intelligence algorithms and is used with various asset allocation models such as mean-variance model, Black-Litterman model and risk parity model. Risk parity model is a typical risk-based asset allocation model which is focused on the volatility of assets. It avoids investment risk structurally. So it has stability in the management of large size fund and it has been widely used in financial field. XGBoost model is a parallel tree-boosting method. It is an optimized gradient boosting model designed to be highly efficient and flexible. It not only makes billions of examples in limited memory environments but is also very fast to learn compared to traditional boosting methods. It is frequently used in various fields of data analysis and has a lot of advantages. So in this study, we propose a new asset allocation model that combines risk parity model and XGBoost machine learning model. This model uses XGBoost to predict the risk of assets and applies the predictive risk to the process of covariance estimation. There are estimated errors between the estimation period and the actual investment period because the optimized asset allocation model estimates the proportion of investments based on historical data. these estimated errors adversely affect the optimized portfolio performance. This study aims to improve the stability and portfolio performance of the model by predicting the volatility of the next investment period and reducing estimated errors of optimized asset allocation model. As a result, it narrows the gap between theory and practice and proposes a more advanced asset allocation model. In this study, we used the Korean stock market price data for a total of 17 years from 2003 to 2019 for the empirical test of the suggested model. The data sets are specifically composed of energy, finance, IT, industrial, material, telecommunication, utility, consumer, health care and staple sectors. We accumulated the value of prediction using moving-window method by 1,000 in-sample and 20 out-of-sample, so we produced a total of 154 rebalancing back-testing results. We analyzed portfolio performance in terms of cumulative rate of return and got a lot of sample data because of long period results. Comparing with traditional risk parity model, this experiment recorded improvements in both cumulative yield and reduction of estimated errors. The total cumulative return is 45.748%, about 5% higher than that of risk parity model and also the estimated errors are reduced in 9 out of 10 industry sectors. The reduction of estimated errors increases stability of the model and makes it easy to apply in practical investment. The results of the experiment showed improvement of portfolio performance by reducing the estimated errors of the optimized asset allocation model. Many financial models and asset allocation models are limited in practical investment because of the most fundamental question of whether the past characteristics of assets will continue into the future in the changing financial market. However, this study not only takes advantage of traditional asset allocation models, but also supplements the limitations of traditional methods and increases stability by predicting the risks of assets with the latest algorithm. There are various studies on parametric estimation methods to reduce the estimated errors in the portfolio optimization. We also suggested a new method to reduce estimated errors in optimized asset allocation model using machine learning. So this study is meaningful in that it proposes an advanced artificial intelligence asset allocation model for the fast-developing financial markets.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.49-56
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• 2010

Developments of radioprotective agents are important issues for minimizing the troubles and the effective treatments in radiotherapy. But few agents are useful in clinical and practical fields. It was shown that trace elements in alcohol beverages might have radioprotective effect. In this study, the types of cell death of lymphocytes according to the commercial alcohol beverage was investigated. Normal healthy volunteers ingested distilled water, beer or soju containing $81.5mg{\cdot}dl^{-1}$ ethyl ahcohol, respectively. After 2 hours, their blood were sampled with their consents. Fraction of lymphocytes was isolated by density gradient method with Histopaque-1077 (Sigma) and irradiated with dose from 0.5 to 5 Gy. After 60 hour incubation, the cells were harvested and analysed by flow cytometry. Cell viability was decreased by dose dependent manner. Cell viability of beer group was reduced about 15% compared with control group. Apoptosis in soju group was reduced about 20% compared with control group. Apoptosis of beer and control groups are similar. Necrosis of soju group significantly increased about 35% compared with control group. Early apoptosis of beer group was increased compared with control group. Early apoptosis of soju group was decreased about 25% compared with control group. Late apoptosis of beer and control group was increased by dose dependent manner. Late apoptosis of soju group was increased about 20-30% compared with control group. Late apoptosis of soju was increased and the radioprotective effect of soju was minimal because late apoptosis induced the cell necrosis. In case of soju trace elements, total cell apoptosis was decreased about 20% and early cell apoptosis was remarkably low. In this case, mitotic cells death may be dominant mechanism. Therefore, trace elements in soju may not be effective radioprotective agents.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.75-82
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• 2013

The simultaneous analysis and monitoring of aflatoxin $B_1$, $G_1$, $B_2$, $G_2$ and ochratoxin A in foods were carried out by HPLC with fluorescence detection. The samples were extracted with methanol/water mixture. The extract was centrifuged, diluted with phosphate buffer saline (PBS), filtered, and applied to an immunoaffinity column containing antibodies specific to both aflatoxins and ochratoxin A. After washing the column with PBS and water, the toxins were eluted from the column with methanol, and quantified by HPLC, with a run time of approximately 30 min. The recoveries for aflatoxin $B_1$, $G_1$, $B_2$, $G_2$ and ochratoxin A in foods were 78.4~101.5%, 73.3~102.1%, 81.7~106.7%, 67.0~104.6% and 78.7~120.8%, respectively. The limits of detection of aflatoxins and ochratoxin A ranged from 0.05 to $0.18{\mu}g/kg$. According to monitoring result with the established method, aflatoxin $B_1$ and ochratoxin A were found in 13 of 151 domestic commercial foods. The contamination levels were $0.32{\sim}1.80{\mu}g/kg$ for aflatoxin $B_1$ and $0.97{\mu}g/kg$ for ochratoxin A. Therefore, this study showed all commercial foods monitored were safe under the Korean standards for aflatoxins and ochratoxin A.

• Investigative Magnetic Resonance Imaging
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• v.22 no.1
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• pp.1-9
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• 2018

Purpose: This study was designed to optimize the flip angle (FA) and scan timing of the hepatobiliary phase (HBP) using the 3D T1-weighted, gradient-echo (GRE) imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique on gadoxetic acid-enhanced 3T liver MR imaging. Materials and Methods: Sixty-two patients who underwent gadoxetic acid-enhanced 3T liver MR imaging were included in this study. Four 3D T1-weighted GRE imaging studies using the CAIPIRINHA technique and FAs of $9^{\circ}$ and $13^{\circ}$ were acquired during HBP at 15 and 20 min after intravenous injection of gadoxetic acid. Two abdominal radiologists, who were blinded to the FA and the timing of image acquisition, assessed the sharpness of liver edge, hepatic vessel clarity, lesion conspicuity, artifact severity, and overall image quality using a five-point scale. Quantitative analysis was performed by another radiologist to estimate the relative liver enhancement (RLE) and the signal-to-noise ratio (SNR). Statistical analyses were performed using the Wilcoxon signed rank test and one-way analysis of variance. Results: The scores of the HBP with an FA of $13^{\circ}$ during the same delayed time were significantly higher than those of the HBP with an FA of $9^{\circ}$ in all the assessment items (P < 0.01). In terms of the delay time, images at the same FA obtained with a 20-min-HBP showed better quality than those obtained with a 15-min-HBP. There was no significant difference in qualitative scores between the 20-min-HBP and the 15-min-HBP images in the non-liver cirrhosis (LC) group except for the hepatic vessel clarity score with $9^{\circ}$ FA. In the quantitative analysis, a statistically significant difference was found in the degree of RLE in the four HBP images (P = 0.012). However, in the subgroup analysis, no significant difference in RLE was found in the four HBP images in either the LC or the non-LC groups. The SNR did not differ significantly in the four HBP images. In the subgroup analysis, 20-min-HBP imaging with a $13^{\circ}$ FA showed the highest SNR value in the LC-group, whereas 15-min-HBP imaging with a $13^{\circ}$ FA showed the best value of SNR in the non-LC group. Conclusion: The use of a moderately high FA improves the image quality and lesion conspicuity on 3D, T1-weighted GRE imaging using the CAIPIRINHA technique on gadoxetic acid, 3T liver MR imaging. In patients with normal liver function, the 15-min-HBP with a $13^{\circ}$ FA represents a feasible option without a significant decrease in image quality.

• Neonatal Medicine
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• v.18 no.2
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• pp.189-196
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• 2011

Purpose: Surfactants have been used to improve oxygenation for infants with meconium aspiration syndrome (MAS). We evaluated the change of pulmonary indices after surfactant therapy for MAS through a systematic meta-analysis. Methods: Relevant randomized controlled studies (RCTs) were identified by database searches in MEDLINE, EMBASE, and CENTRAL, up to June 2011, and by additional hand searches. Data were extracted regarding pulmonary indices, such as the oxygen index and arterial alveolar oxygen gradient. Meta-analyses were separately conducted for the studies of surfactant lavage therapy and surfactant bolus therapy. The risk of bias was assessed, and clinical as well as statistical heterogeneities were also investigated. Results: Two RCTs for bolus surfactant therapy and two RCTs for surfactant lavage therapy were identified. The oxygenation index results were heterogeneous between the two studies in which bolus surfactant therapy was given, while a/A $PO_2$ showed significantly better results in the treatment group over time after use of surfactant (12 hours: WMD 0.08, 95% CI 0.04-0.12; 24 hours: WMD 0.17, 95% CI 0.06-0.28). For surfactant lavage therapy, both studies consistently suggested an interventional benefit in terms of the pulmonary indices although it did not reach statistical significance. Conclusion: Surfactant therapy appeared to improve oxygenation of infants with MAS. Since a limited number of RCTs are available in the current literature and those studies were also clinically heterogeneous in terms of illness severity and the method of surfactant use, further research is needed to gather evidence to support surfactant therapy in MAS.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.727-734
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• 2004

The Lecompte procedure for transposition of the great arteries has an advantage because it obviates the need for an extracardiac conduit for the reconstruction of the pulmonary outflow tract. We evaluated the effectiveness and the application of the Lecompte procedure. Material and Method: A retrospective review was conducted of the records of 46 patients who underwent the Lecompte procedure during the past 15 years. Mean age at operation was 29.2$\pm$20.3 (range: 3∼83) months. The diagnoses involved anomalies of the ventriculoarterial connection with ventricular septal defect and pulmonary outflow tract obstruction, such as transposition of the great arteries, double-outlet right ventricle, and double-outlet left ventricle. Result: Early mortality was 4.4% (2 of 46 patients) and late mortality was 6.8% (3 of 44). The mean follow-up was 11.2$\pm$6.9 years. Eighteen patients (43.9% of survivors, n=41) had pulmonary stenosis (pressure gradient above 30 mmHg), the main reason for which was a calcified monocusp valve (n=15, 83.3%). Seventeen of 46 patients (37.0%) underwent reoperation: 15 for pulmonary stenosis, 5 for residual ventricular septal defect, 4 for left ventricular outflow tract obstruction, 3 for pulmonary insufficiency, and 4 for other causes. The cumulative survival rates were 91.3$\pm$4.2%, and 87.0$\pm$5.8% at 10 and 15 years, respectively. The actuarial probabilities of freedom from reoperation for pulmonary stenosis were 90.6$\pm$4.5%, 73.9$\pm$7.3%, and 54.0$\pm$10.4% at 5, 10, and 15 years, respectively. Conclusion: The Lecompte procedure is an effective treatment modality. Repair in early age is possible with acceptable morbidity and mortality, but recurrent right ventricular outflow tract obstruction caused by degeneration of the monocusp valve is a problem that needs resolution.