• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1090-1098
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• 2005

Benzoyl peroxide is very toxic to aquatic organisms but environmental concentration or exposure effects were not studied. Distribution of the chemical among multimedia environment was estimated using EQC(Equilibrium Criterion) model based on the physical-chemical properties to evaluate the risk of benzoyl peroxide in environment. Level I describes a situation that 100,000 kg of benzoyl peroxide is emitted into the environment which is equilibrium and steady-state without degradation and advection condition. Level II describes a situation that a constant rate of 1,000kg/h of benzoyl peroxide is continuously discharged into the environment which is equilibrium and steady-state with degradation and advection condition. Level III describes a situation that 1,000 kg/h of benzoyl peroxide is continuously introduced in each air, water, soil, and sediment compartment which are non-equilibrium and steady-state with degradation, advection, and inter-media transfer condition. In Level I and II calculations the chemical was distributed to soil(68.3%) and water(28.7%). In Level III calculation it was primarily distributed to soil(99.9%) and overall residence time was estimated to be 3.4 years. Benzoyl peroxide can be persistent in environment.

• Journal of Biomedical Engineering Research
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• v.38 no.2
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• pp.62-73
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• 2017

To identify a solution for the restricted availability of healthy lungs and the high risk of immune rejections following organ transplantation, tissue engineering techniques for culturing lungs have been studied by many research groups. The most promising method for culturing lungs is the utilization of a bio-scaffold that was prepared using harvested organs from human donors or other animals by removing their original cells. In this study, a pulsatile perfusion pump was used to alleviate the cell removal effect with the high fluid-dynamic power of the perfusion stream during the decellularization process, while other conventional studies focused on chemical methods to identify efficient detergents. The purpose of this study was to analyze the developed device by using energy equivalent pressure (EEP), which is an indicator of pulsatility, to understand the characteristics of pulsatile energy transmitted according to the load size by using the artificial model and compare it with the measured EEP. The pulsatility of the device can be estimated with the concept of fluid-dynamic energy during a particular constant time period or fluid-dynamic power represented as EEP and EEP increment. Because the measured EEP of perfusion flow during decellularization can be changed by the amount of fluid leakage and the degree of clogging in the capillary vessels, EEP should be measured to determine whether the decellularization is progressing without problems. The decrement of EEP caused by the high perfusion resistance was observed from some experimental results that were obtained with artificial models. EEP can be used to monitor the decellularization process after analyzing the varying EEP according to the amount of load. It was confirmed that the EEP was maintained at a high level in the experiment using the harvested lungs from 12-13-week-old rats. In addition, it was confirmed that the cell removal time was faster than when continuous perfusion was performed. In this study, pulsatile power delivered to the lungs was measured to monitor the process of cell removal, and it serve as the evidence for efficient decellularization.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.369-376
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• 2019

Ship hydrodynamics in the confined waterways is challenging. When a ship is maneuvering in confined waterways, the hydrodynamic behavior may vary significantly because of the hydrodynamic interaction between the bottom of the ship hull and the seabed, or so-called shallow water effects. Thus, an accurate prediction of shallow water and bank effects is essential to minimizing the risk of the collision and the grounding of the ships. The hydrodynamic derivatives measured by the virtual captive model test provide a path to predicting the change in ship maneuverability. This paper presents a numerical simulation of captive model tests to predict the maneuverability of a ship in confined waterways. Also, straight and zig-zag simulation were conducted to predict the trajectory of a ship maneuvering in confined waterways. The results showed that the asymmetric flow around a ship induced by vicinity of banks causes pressure differences between the port and starboard sides and the trajectory of a ship maneuvering in confined waterways.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.173-183
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• 2006

Purpose of this study was to estimate of soil erosion, which is related with crop productivity and water quality in watershed, in Seonakdong river watershed using USLE. The data set for USLE estimation were derived from detailed digital map(K factor), satellite imagery(C and P factors) and DEM(LS factor). The R factor was calculated by AWS data from Kimhae agricultural technology center. The soil loss from arable land was equivalent of 31.5% of total soil loss in Seonakdong river watershed. The soil loss amount of paddy field and upland were 2.8% and 97.2% of arable land, respectively, even in the area where paddy field was occupied much largely as 76.3%. The reason of large amount of soil loss from upland was that 30.4% of upland was distributed at "severe" and "very severe" soil erosion grade in watershed. The distribution of soil erosion grade during cropping season(May-Sept.) was similar to the annual soil loss. Soil erosion of non-cropping season(Oct.-Apr.) was small due to a low R factor. But, soil erosion grade of near mountain footslope areas showed severe and very severe even in non-cropping season.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.231-236
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• 2013

Background: Published data regarding the association between xeroderma pigmentosum group D (XPD) Lys751Gln and Asp312Asn polymorphisms and gastric cancer susceptibility havew been inconclusive. This meta-analysis was therefore performed toobtain a more precise estimation of any relationship. Materials and Methods: A comprehensive literature search was conducted to identify all case-control studies of Lys751Gln and Asp312Asn polymorphisms and susceptibility to gastric cancer. Summary odds ratios (ORs) and its 95% confidence intervals (95% CIs) were calculated using a random-effects model with the software STATA (version10.0). Results: A total of 12 case-control studies including 3,147 cases and 4,736 controls were included. Overall, no significant associations were found in some models (for Lys751Gln: Lys/Gln vs Lys/Lys: OR=1.144, 95% CI=0.851-1.541, Gln/Gln vs Lys/Lys: OR=1.215, 95% CI = 0.740-1.955, dominant model: OR=1.137, 95% CI=0.818-1.582; recessive model: OR=1.123, 95% CI=0.765-1.650; for Asp312Asn: Asp/Asn vs Asp/Asp: OR=1.180, 95% CI=0.646-2.154, dominant model: OR=1.380, 95% CI = 0.812-2.346), but significantly elevated susceptibility was found for Asp312Asn polymorphism in some models (Asn/Asn vs Asp/Asp: OR=2.045, 95% CI=1.254-3.335, recessive model: OR=1.805, 95% CI =1.219-2.672), for the additive model, the XPD Lys751Gln and Asp312Asn polymorphisms were not significantly associated with gastric cancer susceptibility. In stratified analyses, significantly elevated susceptibility was found for some models in the Chinese population. Conclusion: This meta-analysis suggested the XPD Asp312Asn polymorphism might be a potential biomarker of gastric cancer susceptibility in overall population, while both XPD Lys751Gln and Asp312Asn polymorphisms might be risk factors of gastric cancer susceptibility in Chinese.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.33-43
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• 2016

Public transportation card data, which is collected for purposes of the Integrated Public Transportation Fare System, provides neither transfer time nor transfer frequency occurring on the metropolitan city-rail (MCR). And because there are no transfer toll gates installed on the MCR, data on transfers between lines are estimated through means such as elicitations using survey questionnaire, or otherwise through macroscopic observations, which poses the risk of transfer time and frequencies being underestimated. For the accurate estimation thereof, an explanation of the transit path that arises between the Entry-and Exit-Gates must be provided. The purpose of this research is twofold : 1) to build a transit path model to reflect the current state of transfer movements on the basis of transportation card reader data, and 2) to deduce information on transfers occurring in the greater metropolis. To achieve these aims, the idea of Big Nodes is introduced in the model to align transportation card reader operation system characteristics with those of the MCR network. The link-label method is applied in the model as well to make certain that the MCR network runs in an effective manner. Administrative information obtained by the transportation card reader is used to derive transfer time and frequency both in the city's mid-zones, and in the Seoul-Gyeonggi-Incheon district's large-zones. Public transportation card data from a single specific day in year 2014 is employed in the building of the quantified transfer specific data. Extended usage thereof as providing comprehensive data of transfer resistance on the MCR is also examined.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.3
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• pp.191-201
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• 2010

The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3101-3103
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• 2016

Background: According to the most recent estimation of GLOBOCAN, Cambodia has the highest incidence and mortality rate of cervical cancer in Southeast Asia. A screen-and-treat strategy using visual inspection with acetic acid (VIA test) and cryotherapy has been implemented in Cambodia's national cervical cancer screening program since 2013. However, where resources are available, cervical cytology with or without high-risk HPV DNA testing is the preferred screening method used in this country. Aim: This study aims to calculate the prevalence of abnormal cervical cytology and explain the possible factors contributing to a reduced quality of cervical cytology among women participating in a hospital-based cervical cancer screening program in Cambodia. Materials and Methods: A descriptive study was conducted using information from the cytology and pathology database in the Department of Pathology of Calmette Hospital between January 2012 and December 2015. Prevalence of abnormal cervical cytology, based on the Bethesda 2001 classification, was calculated. Data on the adequacy of cytological specimens were analyzed in order to explain the factors contributing to a reduced quality of cervical cytology interpretation. Results: Among 6,207 women who participated in the cervical cancer screening program at Calmette Hospital during 2012 and 2015, 388 (6.25%) had abnormal cytology, which could be classified into Atypical Squamous Cells of Undetermined Significance (92 cases; 1.48%), Atypical Squamous Cells - Cannot Exclude High-Grade Intraepithelial Lesion (13 cases; 0.21%), Atypical Glandular Cells (11 cases; 0.18%), Low-Grade Squamous Intraepithelial Lesion (221 cases; 3.56%), High-Grade Squamous Intraepithelial Lesion (26 cases; 0.42%), and Squamous Cell Carcinoma (25 cases; 0.40%). Unsatisfactory smears made up 12.2% of the total cases. The most frequently identified factor leading to unsatisfactory smears was the absence of cells from the transformation zone. Conclusions: The present study showed an overall prevalence of abnormal cervical cytology of 6.25%, which is comparable to that in many large population-based studies in the Asia Pacific region. Nevertheless, the remarkably high rate of unsatisfactory smears in this study justifies further improvement in specimen sampling among Cambodian gynecologists.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.717-722
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• 2013

Background: Breast cancer is the most common cancer among women worldwide. The aim of this study was to investigate the relationship between tumor size and axillary lymph node involvement (ALNI) in patients with invasive lesions, to find the best candidates for a full axillary dissection. Additionally, we evaluated the association between tumor size and invasive behavior. The study was based on data from 789 patients with histopathologically proven invasive breast cancer diagnosed in Shohada University hospital in Tehran, Iran (1993-2009). Cinical and histopathological characteristics of tumors were collected. Patients were divided into 6 groups according to primary tumor size: group I ($0.1-{\leq}1cm$), II ($1.1-{\leq}2cm$), III ($2.1-{\leq}3cm$), IV ($3.1-{\leq}4cm$), V ($4.1-{\leq}5cm$) and VI (>5cm). The mean(${\pm}SD$) size of primary tumor at the time of diagnosis was $3.59{\pm}2.69$ cm that gradually declined during the course of study. There was a significant correlation between tumor size and ALNI (p<0.001). A significant positive correlation between primary tumor size and involvement of surrounding tissue was also found (p<0.001). The mean number of LNI in group VI was significantly higher than other groups (p<0.05). We observed more involvement of lymph nodes, blood vessels, skin and areola-nipple tissue with increase in tumor size. We found 15.3% overall incidence of ALNI in tumors ${\leq}2cm$, indicating the need for more investigation to omit full axillary lymph node dissection with an acceptable risk for tumors below this diameter. While in patients with tumors ${\geq}2cm$, 84.3% of them had nodal metastases, so the best management for this group would be a full ALND. Tumor size is a significant predictor of ALNM and involvement of surrounding tissue, so that an exact estimation of the size of primary tumor is necessary prior to surgery to make the best decision for management of patients with invasive breast cancer.

• Journal of Nutrition and Health
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• v.48 no.6
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• pp.496-506
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• 2015

Purpose: The purpose of this study was to estimate dietary flavonoids intake of Korean adolescents. Methods: Using data from the 2007-2012 Korean National Health and Nutrition Examination Survey, a total of 3,957 subjects aged 12-18 were included in this study. We estimated individual daily intake of total flavonoid and six flavonoid classes including flavonols, flavones, flavanones, flavan-3-ols, anthocyanidins, and isoflavones by linking food consumption data with the flavonoids in the commonly consumed food database. The distribution of sociodemographic, health-related, and dietary factors according to flavonoids intake was examined. Results: Average dietary flavonoids intake of the study subjects was 195.6 mg/d in girls, and 189.4 mg/d in boys. The highest flavonoids intake group consumed significantly more fiber, vitamin C, legumes, fruits, and vegetables (p < 0.01) and less fat, grains, meats and dairy foods than other lower consumption groups (p < 0.001). Dietary flavonoid intake showed negative correlation with waist circumference and systolic blood pressure (p < 0.05). Conclusion: This study provided basic data for estimation of flavonoids intake of Korean adolescents. Further research will be required for analysis of the association of flavonoids intake and health-related factors such as cardiovascular risk factors.