• Journal of Chest Surgery
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• v.37 no.4
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• pp.313-321
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• 2004

Excellent clinical results of the arterial switch operation and the limited availablity of the intraventricular rerouting has recently made an arterial switch operation to become the therapeutic method of choice for the repair of double-outlet right ventricle (DORV) with subpulmonary ventricular septal defect (VSD). The early and midterm outcomes of arterial switch operation for this anomaly were evaluated. Material and Method: Between August 1994 and July 2002, 13 patients underwent an arterial switch operation for the correction of double-outlet right ventricle with subpulmonary VSD at Dong-A university hospital.. The 50% rule was used to define DORV. Median age and mean body weight were 27 days (range, 3-120 days) and 3.8$\pm$0.7kg (range, 2.92-5.3kg) respectively. Aortic arch anomalies were associated in 6 cases (46.2%), which were all repaired through one-stage operation. The relationship of the great arteries were side-by-side in 8 cases (61.5%) and anteroposterior in 5 (38.5%). Coronary artery patterns were 1 LCx-2R in 6 cases, retropulmonary left coronary artery (LCA) in 6, and intramural LCA in 1 respectively. The enlargement of VSD was required in 1 patient and the patch enlargement of right ventricular outflow tract was performed in another one patient. The Lecompte maneuver was used in all but 3 patients with a side by side relationship of the great arteries. Result: Overall postoperative hospital mortality was 23.1 % (3/13). All operative deaths were occurred in the patients with aortic arch anomalies. There was one late death related to the postoperative complication of the central nerve system during the mean follow-up of 41.3$\pm$30.7 months. Pulmonary valvar stenosis (＞30mmHg of pressure gradient) developed in 1 patient (10%) and left pulmonary artery stenosis in 2 (20%), among them, one required reoperation 52 months after repair. There was an asymptomatic patient with moderate aortic regurgitation. 5-year survival rate including operative deaths was 68.3%. Conclusion: Although the operative mortality is high in the patients with aortic arch anomaly, the arterial switch operation for DORV with supbpulmonary VSD can be performed with low operative mortality and low reoperation rate in the patients Without arch anomaly. The arterial switch operation can be considered a good option for this complex anomaly.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.279-287
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• 1997

This study was carried out to identify the analysis of vegetation-environment relationships of the coniferous forests in subalpine districts of Mt. Chiri by two-way indicaton species analysis(TWINSPAN) and CCA. The results are summarized as follows; The subalpine coniferous forest in Mt. Chin was classified Abies koreana community group by the TWINSPAN method. The Abies koreana community group was classified Abies koreana-Pinus densiflora, Abies koreana-Quercus mongolicd and Abies koreana-Picea jezoensis. The Abies koreana-Quercus mongolica community classified into two subcommunities, typical and Pinus koraiensis subcommunity. The Abies koreana-Picea jezoensis community classified into three subcommunities such as typical, Taxus cuspidate and Cornus controversa subcommunity. The subalpine conifers commnities in Mt. Chiri could be classified into six vegetation units, which consisted of three vegetation communities and five subcommunities. The relationship between vegetation community and influencing environmental factors was analyzed by using the CCA ordination method. It was found that altitude, concentrations of $Ca^{++}$ and $Mg^{++}$ in soil were, major environmental variables, which influence the distribution of vegetation community in the first axis, and $Ca^{++}$ and altitude in the second axis. In the relations of communities and environmental factors by CCA, the optimal ecological habitats of Abies koreana-Pinus densiflora community could be located at low elevations, in which $Ca^{++}$ and $Mg^{++}$ are rich. Abies koreana-Quercus mongolica community prefers the sites in mid-elevation zone, in which $Ca^{++}$ and $Mg^{++}$ are medium level in soil. The optimum site for Abies koreana-Pinus koraiensis community and Abies koreana-Taxus cuspidata community could be high elevations in which $Ca^{++}$ and $Mg^{++}$ are poor. Abies koreana-Cornus controversa community is found in the site at low elevations where $Ca^{++}$ and $Mg^{++}$ are medium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.456-463
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• 1996

The purpose of the present study is to estimate the regional and seasonal variations of dissolved inorganic nitrogen (DIN) flux across the sediment-water interface of the inner and central areas of Hiroshima Bay from August 1994 to May 1995. In addition it compares the measured methods and estimates the effect of DIN released from sediment to the primary production of Hiroshima Bay. One method used in this study is to calculate DIN flux from a concentration gradient between sediment porewaters and the overlying water, and the other method is to measure DIN flux from the sediment-core experiment. The fluxes of $NH_{4}^{+}-N\;and\;NO_{2}^{+}\;+\;NO_{3}^{-}-N$ in the inner area were higher than those in central area, all of which showed seasonal variation. $NH_{4}^{+}-N$ flux was maximum in August, while $NO_{2}^{-}\;+\;NO_{3}^{-}-N$ flux was high in January compared with the other seasons. The calculated $NH_{4}^{+}-N\;and\;NO_{2}^{-}+NO_{3}^{-}-N$ fluxes from sediments were $18.2\~60.8\;{\mu}g-at/m^2{\cdot}hr\;and\;0.24\~18.2\;{\mu}g-at/m^2{\cdot}hr$, respectively. The measured $NH_{4}^{+}-N\;and\;NO_{2}^{-}+NO_{3}^{-}-N$ fluxes across the sediment-water interface were $2.00\~111\;{\mu}g-at/m^2{\cdot}hr\;and\;-265\~82.9\;{\mu}g-at/m^2{\cdot}hr$, respectively. The former was lower than the tatter. The calculated $NH_{4}^{+}-N$ flux showed closer relation to environmental factors (dissolved of gen in the overlying water, temperature and redox condition of the sediments) than the measured one did. On the other hand, in the case of $NO_{2}^{-}+NO_{3}^{-}-N$ flux both the calculated and the measured showed little relation to environmental factors, while they turned out to have stronger relation with their concentration in sediments. DIN released from the sediment is expected to support about $25\%\~67\%$ of the primary production in Hiroshima Bay.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.846-855
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• 1999

Background : Secondary pulmonary hypertension is an important final endpoint in patients with chronic hypoxic lung disease, accompanied by deterioration of pulmonary hemodynamics. The clinical diagnosis of pulmonary hypertension and/or cor pulmonale could be difficult, and simple noninvasive evaluation of pulmonary artery pressures has been an relevant clinical challenge for many years. Doppler echocardiography might to be a more reliable method for evaluating pulmonary hemodynamics in such patients in terms of the accuracy, reproducibility and easiness for obtaining an appropriate echocardiographic window than M-mode echocardiography. The aim of this study was to assess echocardiographic parameters associated with pulmonary arterial hypertension, defined by increasing right ventricular systolic pressure(RVSP), calculated from trans-tricuspid gradient in patients with chronic hypoxic lungs. Method : We examined 19 patients with chronic hypoxic lung disease, suspected pulmonary hypertension under the clinical guidelines by two dimensional echocardiography via the left parasternal and subcostal approach in a supine position. Doppler echocardiography measured RVSP from tricuspid regurgitant velocity in continuous wave with 2.5MHz transducer and acceleration time(AT) on right ventricular outflow tract in pulsed wave for the estimation of pulmonary arterial pressure. Results : On echocardiography, moderate to severe degree of pulmonary arterial hypertension was defined as RVSP more than 40mmHg, presenting tricuspid regurgitation. Increased right ventricular endsystolic diameter and shortened AT were noted in the increased RVSP group. Increased RVSP was correlated negatively with the shortening of AT. Other clinical data, including pulmonary functional parameters, arterial blood gas analysis and M mode echocardiographic parameters were not changed significantly with the increased RVSP. Conclusion : These findings suggest that shortened AT on pulsed doppler can be useful when quantifying pulmonary arterial pressure with increased RVSP in patients with chronic lung disease with hypoxemia. Doppler echocardiography in pulmonary hypertension of chronic hypoxic lungs is an useful option, based on noninvasiveness under routine clinical practice.

• 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.