• Genomics & Informatics
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• v.13 no.3
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• pp.86-89
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• 2015

Because there are clear molecular differences entailing different treatment effectiveness between Korean and non-Korean cancer patients, identifying distinct molecular characteristics of Korean cancers is profoundly important. Here, we report a web-based data repository, namely Korean Cancer Genome Database (KCGD), for searching gene signatures associated with Korean cancer patients. Currently, a total of 1,403 cancer genomics data were collected, processed and stored in our repository, an ever-growing database. We incorporated most widely used statistical survival analysis methods including the Cox proportional hazard model, log-rank test and Kaplan-Meier plot to provide instant significance estimation for searched molecules. As an initial repository with the aim of Korean-specific marker detection, KCGD would be a promising web application for users without bioinformatics expertise to identify significant factors associated with cancer in Korean.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1126-1131
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• 2006

Risk assessment of a railway system should be periodically conducted managing a large amount of accumulating accident/incident data and scenarios, which generally requires enormous time and efforts. Therefore, special information management system is essential for railway risk assessment, where data needed for decisions on managing the railway safety could be promptly supported. The objective of this study is to develop a railway accident analysis program for risk assessment. The program is application running on the web which links railway accident analysts throughout the railway industry to a central database. Data entered, together with associated code tables. is stored on MS-SQL database. The program uses the concepts of accident, safety events, causes, related factors(vehicle, person, infrastructure, tool/equipment), recommendations to bring together the various elements of railway accidents. The program will be useful in finding hazard conditions, accident scenarios, quantitatively assessing the risk, and providing pertinent risk measures, eventually serving to prevent railway accidents and reduce severities of railway accidents.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.301-305
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• 2012

This study was conducted to investigate the microbiological contamination levels in rice cakes and rice flour due to climate change in three areas classified to their temperature and precipitation. We investigated the contamination levels of total aerobic bacteria, coliforms, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Clostridium perfringens of rice flour and 3 rice cakes such as Garaetteok, Sirutteok and Gyeongdan. Contamination levels of total aerobic bacteria in rice flour were 4.9 log CFU/g. In a total of 70 rice flour, yeasts & molds and coliforms were detected in 42 and 52 samples at the levels of 43 CFU/g and 1.29 log CFU/g, respectively. S. aureus were detected in only 1 rice flour (1.66 log CFU/g) out of 70. In an investigation of contamination levels in rice cakes, the population of total aerobic bacteria were highest in Gyeongdan (5.18 log CFU/g) and coliforms were highest in Gareattock (2.93 log CFU/g). There was no detection of E. coli and B. cereus except for only 1 Gareattock (1.20 log CFU/g). There were no differences of contamination levels among the three areas. If constant monitoring of rice cakes and rice flour is conducted on the basis of this study, it is expected to be able to analyze the change of contamination levels in rice cakes and rice flour due to climate change.

• Korean Journal of Medicinal Crop Science
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• v.24 no.2
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• pp.143-151
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• 2016

Background: The public has increasing concerns about herbal crops owing to insufficient information on biological hazards such as foodborne pathogens. Therefore, the objective of this study is the development of a herbal crop quality control system through monitoring with biological hazard analysis. Today, it is estimated that millions of people become ill every year from food contamination. The public demands agricultural products of stable and consistent quality. Governments have the responsibility of establishing the standards, legislation and enforcement programs necessary to control food quality and safety. However, research on the biosafety of herbal crop products is still insufficient. Therefore, the implementation of monitoring systems with high standards is critical for public safety. Methods and Results: In this study, we collected 52 samples of herbal crop products, and conducted both quantitative and qualitative biological hazard analysis. With biological hazard analysis, aerobic bacteria, Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. could be detected. Conclusions: Herbal crops were found to be contaminated with aerobic bacteria at $3.69{\pm}0.32log\;CFU/g$. Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. were not detected in any of the samples. This research suggests that continuous monitoring of biological hazards is required to improve the quality of herbal crops.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.216-220
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• 2002

The microbiological examinations of food service operations were conducted for the hygienic evaluation at four elementary schools in Busan, Korea. Total one hundred and seventy two swabbed samples using sponge were collected from the surface of environments, utensils and equipments of food service facilities and analyzed by measuring the total, coliform and psychrotrophic count. Sampling sites were the surfaces of floors, drains, walls, knives, cutting boards, rubber gloves, vinyl aprons, plastic containers, carriers, shelves, trays, dry shelves, electric tray dryer, food containers, soup containers, rice cookers, frying pans, boiling cookers, refrigerators, dumb waiters and dishwashers. The swabbed samples kept in an ice-parked box were transported to a laboratory and analyzed. The results demonstrated that the degree of contamination depended on the sampling sites. Averages of total counts of surface swab samples were ranged from 0.62 to 7.79 Log CFU/200 cm$^2$. The level of coliforms were ranged from not detectable to 5.26 Log CFU/200 cm$^2$, and those of psychrotrophs from not detectable to 6.15 Log CFU/200 cm$^2$. The severely contaminated sites were dumb waiters, drains, rice cookers, knives, plastic containers and floors. Also cutting boards, rubber gloves, carriers, drying shelves, vinyl aprons, boiling cookers, soup containers, frying pans and refrigerators were highly contaminated with the level of abode 3.5 Log CFU/200 cm$^2$. Therefore, those sites should be focused and controlled according to control points of sanitation standard operating procedures (SSOP). Also, periodic microbiological examination in addition to visual examination is recommended on these highly contaminated sites indicated above results at food service operations in elementary school.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.116-122
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• 2011

This study was conducted to investigate the microbiological hazard of spoons and their cases carried by nursery school children and to evaluate the reduction effects of washing methods and ultraviolet (UV) treatments against Escherichia coli on the spoon and spoon case. A total of 78 spoons and their cases were sampled to test about total aerobic bacteria, coliform bacteria, Staphylococcus aureus, Bacillus cereus and Salmonella spp. Total aerobic bacteria were detected over 2.7 log CFU/100 $cm^2$ in 20 out of 36 spoons (55.6%), 9 out of 20 zipper-type spoon cases (45.0%) and 13 out of 22 plastic-type spoon cases (59.1%). Coliform bacteria were also detected in 19 out of 36 spoons (52.8%), 14 out of 20 zipper-type spoon cases (70.0%) and 14 out of 22 plastic-type spoon cases (63.6%). The pathogens tested in this study were not found in all samples except for the zipper-type spoon cases which were contaminated with Staph. aureus (2 samples) and B. cereus (3 samples). The results indicated that the sanitary conditions of spoons and their cases should be improved promptly. To evaluate the reduction effects of washing methods and UV treatments against E. coli, the spoons and their cases were treated at different cleaning times with and without soap, and different UV exposure times, respectively. E. coli with initial cell number of 4 log CFU on the spoons and their cases was not detected when they were cleaned at running water for 30 sec after dish sponging with soap for 30 sec. In UV treatments, E. coli with the same level of washing method was not detected after UV exposure for 15 minute in the spoons and their cases. From the results, the washing and UV treatment should be used to control the microbial contamination of spoons and their cases for more than 1 and 15 minutes, respectively.

• Journal of Environmental Health Sciences
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• v.37 no.5
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• pp.376-386
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• 2011

Objectives: The aim of this study was to evaluate the microbial hazards posed by food utensils and fixtures in food service operations at selected middle and high schools located in Seoul, Korea. Methods: We collected 200 samples of utensils and fixtures including cups, spoons/chopsticks, food trays and tables from five different schools in Seoul. Target microorganisms of this study were divided into two groups: total bacterial count and total coliform as indicators of microbial contamination and Bacillus cereus and Staphylococcus aureus as pathogens of food poisoning. We used selective media to quantify microbial concentration and 16S rRNA PCR assay for qualitative analysis. In addition, intensive interviews with nutritionists were conducted and observations were made to identify factors that may affect microbial contamination. Logistic regression analysis was employed to examine the relationship between the microbial concentration and operation characteristics of each operation. Results: The level of microbial concentration in school B and C were significantly lower than in school A, D and E (p<0.05). Some samples from school A, D and E showed over 3.4 log CFU/100 $cm^2$ (total bacterial count) and 1.0 log CFU/100 $cm^2$ (total coliform), which requires immediate hygienic action. The number of customers per staff member, periodicity of hygiene education for staff and daily operation time of sterilizers were also found to be important factors related with the microbial contamination of food service operations. Conclusions: These results suggested that not only a HACCP (Hazard Analysis and Critical Control Point) approach, but also efforts to assess internal risk factors within operations be needed to reduce the microbial contamination of food utensils and fixtures. This study is expected to provide preliminary data for assessing microbial hazards in food service operations.

• Journal of Chest Surgery
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• v.40 no.10
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• pp.680-684
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• 2007

Background: Complete surgical resection is the most effective treatment for stage IB non-small cell lung cancer (NSCLC). Recurrence accounts for the disappointing survival rates after resection. There has been renewed interest in adjuvant therapy after complete resection. Appropriate selection of effective adjuvant therapy will depend on the prognostic factors for recurrence. Material and Method: The study included 114 patients with completely resected stage IB NSCLC. The variables selected for the study were gender, age, the type of resection, cell type, the degree of differentiation, the tumor size and the presence of visceral pleura invasion. The Kaplan-Meier method was used to estimate the survival and disease-free survival rate. The results were compared using the log rank test. Multivariate analysis was performed by Cox's proportional hazard model. Two-sided p-valves < 0.05 were considered to be statistically significant. Result: The 3-year overall survival and the disease-free survival rates were 87.0% and 79.4%, respectively. The degree of differentiation showed a significant influence on disease-free survival according to the univariate analysis. According to the multivariate analysis, a poor grade of differentiation was a significant poor prognostic factor. Conclusion: These results demonstrate that poor differentiation may be a poor prognostic factor for patients with completely resected IB NSCLC. Therefore, the patients with a poor grade of differentiation may require adjuvant therapies.

• Korean Journal of Radiology
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• v.22 no.12
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• pp.1974-1984
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• 2021

Objective: This study aimed to compare the efficacy between no-touch (NT) radiofrequency ablation (RFA) and conventional RFA using twin internally cooled wet (TICW) electrodes in the bipolar mode for the treatment of small hepatocellular carcinomas (HCC). Materials and Methods: In this single-center, two-arm, parallel-group, prospective randomized controlled study, we performed a 1:1 random allocation of eligible patients with HCCs to receive NT-RFA or conventional RFA between October 2016 and September 2018. The primary endpoint was the cumulative local tumor progression (LTP) rate after RFA. Secondary endpoints included technical conversion rates of NT-RFA, intrahepatic distance recurrence, extrahepatic metastasis, technical parameters, technical efficacy, and rates of complications. Cumulative LTP rates were analyzed using Kaplan-Meier analysis and the Cox proportional hazard regression model. Considering conversion cases from NT-RFA to conventional RFA, intention-to-treat and as-treated analyses were performed. Results: Enrolled patients were randomly assigned to the NT-RFA group (37 patients with 38 HCCs) or the conventional RFA group (36 patients with 38 HCCs). Among the NT-RFA group patients, conversion to conventional RFA occurred in four patients (10.8%, 4/37). According to intention-to-treat analysis, both 1- and 3-year cumulative LTP rates were 5.6%, in the NT-RFA group, and they were 11.8% and 21.3%, respectively, in the conventional RFA group (p = 0.073, log-rank). In the as-treated analysis, LTP rates at 1 year and 3 years were 0% and 0%, respectively, in the NT-RFA group sand 15.6% and 24.5%, respectively, in the conventional RFA group (p = 0.004, log-rank). In as-treated analysis using multivariable Cox regression analysis, RFA type was the only significant predictive factor for LTP (hazard ratio = 0.061 with conventional RFA as the reference, 95% confidence interval = 0.000-0.497; p = 0.004). There were no significant differences in the procedure characteristics between the two groups. No procedure-related deaths or major complications were observed. Conclusion: NT-RFA using TICW electrodes in bipolar mode demonstrated significantly lower cumulative LTP rates than conventional RFA for small HCCs, which warrants a larger study for further confirmation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.2
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• pp.68-75
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• 2014

Objectives: This study was performed to analyze the cumulative survival rate of Osstem implants (Osstem Implant Co., Ltd.) over a seven-year period. Materials and Methods: A total of 105 patients who had 467 Osstem implants that were placed at the Section of Dentistry, Seoul National University Bundang Hospital (Seongnam, Korea) from June 2003 through December 2005 were analyzed. The life table method and a cross-tubulation analysis, log rank test were used to evaluate the survival curve and the influence that the prognostic factors. The prognostic factors, i.e., age and gender of patients, diameter and length, type of implants, bone graft history and loading time were determined with a Cox proportional hazard model based on logistic regression analysis. Results: The seven-year cumulative survival rate of Osstem implants was 95.37%. The Cox proportional hazard model revealed that the following factors had a significant influence on survival rate; increased diameter, reduced prosthetic loading period and performance of bone grafting. Conclusion: The osstem implants showed satisfactory results over the seven-year study period.