• The Korean Journal of Ecology
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• v.23 no.1
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• pp.25-32
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• 2000

To analyze the relationship between climatic factors (monthly temperatures and precipitations) and the radial growths or Pinus densiflora with different topographical settings in Worak National Park, Korea, 20 stands were chosen and 10 trees were selected from each stand. After crossdating, each ring-width series was double detrended (standardized) by fitting first a negative exponential or straight regression line and secondly a 60-year cubic spline. The growth patterns coud be categorized by four groups using cluster analysis. Cluster Ⅰ stand has north aspect, but others have south or southwest aspects. Cluster Ⅰ (one), cluster Ⅱ (ten), and cluster Ⅲ (two) stands are located in lower. elevation (305∼580 m), however, cluster Ⅳ (seven) stands are located in higher elevation, mostly in 560～870 m. Cluster Ⅱ and Ⅲ stands are located at similar elevation with the same aspect, however, cluster Ⅱ stands are located on more rocky and stiff slope with shallow soil depth. The response functions were used to examine the difference in the relationships between climatic factors and tree growths among the 4 cluster chronologies. The climatic factors are not limiting the growth in the cluster Ⅰ stand as highly as in other cluster plots because of rather mesic conditions in the north slope. The precipitation in the spring appears to be the main limiting factor in the cluster Ⅱ stands. The topographical characteristics of the sites of cluster Ⅱ, shallow soil depths on the rocky slope in the south aspect at lower elevation, may enhance the sensitivity of growth to moisture stress. In cluster Ⅲ and cluster Ⅳ, winter and spring temperature prior to the growth become more important than for cluster Ⅱ. This pattern is com-mon for Pinus densiflora trees growing in higher. elevation (equation omitted 800 m) in South Korea. It nay be re-lated with preconditioning effects of temperature as the temperature decreases with increasing elevation (cluster Ⅳ) or in the valley (cluster Ⅲ). The results obtained by tree-ring analysis were digitalized by GIS and spatio-temporal information on tree-ring data and topographic setting were analyzed and displayed simultaneously. The results of this study can be used to predict the future change of Pinus densiflora ecosystem to climate change expected in central Korea.

• Neonatal Medicine
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• v.18 no.2
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• pp.272-279
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• 2011

Purpose: The incidence of nosocomial infection caused by Gram-negative bacilli (GNB) has increased in neonatal intensive care units (NICU). This study identified the progression of sepsis caused by GNB colonization and analyzed the risk factors associated with using periodic stool culture surveillance. Methods: We included 86 newborns admitted to the NICU, Kosin University Gospel Hospital from October 2007 to May 2008. Three stool specimens were collected right after birth and two more were collected at 2 week intervals. The risk factors related to GNB colonization were established from each medical record and related references. Results: The incidence of colonization by GNB was 22 (25.6%) per 86 neonates but none had culture-proven sepsis. The three most commonly isolated GNB were Pseudomonas aeruginosa, Enterobacter cloacae, and Citrobacter freundii. Approximately 89% (32/36) of isolated GNB were susceptible to amikacin. The probability of GNB colonization increased in infants who were fed a small volume during enteral feeding. In contrast, delayed enteral feeding resulted in a decreased probability for GNB colonization. Conclusion: Colonized GNB in the intestine was confirmed by enteric surveillance culture of newborns admitted to the NICU. However, we found no evidence of culture-proven GNB sepsis. As lower feeding volume on the colonization day is a risk factor for GNB colonization, the chance for GNB colonization should be considered when feeding intolerance is present.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.393-400
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• 2011

In a large scale survey, cluster sampling design in which a set of observation units called clusters are selected is often used to satisfy practical restrictions on time and cost. Especially, a two stage cluster sampling design is preferred when a strong intra-class correlation exists among observation units. The sample Primary Sampling Unit(PSU) and Secondary Sampling Unit(SSU) size for a two stage cluster sample is determined by the survey cost and precision of the estimator calculated. For this study, we derive the optimal sample PSU and SSU size when the population SSU size across the PSU are di erent by extending the result obtained under the assumption that all PSU have the same number of SSU. The results on the sample size are then applied to the $4^{th}$ Korea Hospital Discharge results and is compared to the conventional method. We also propose the optimal sample SSU (discharged patients) size for the $7^{th}$ Korea Hospital Discharge Survey.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.297-303
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• 2000

Gamma irradiation at 20 kGy was applied to Kanjang (soy sauce), Doenjang (soybean paste), Kochujang (hot pepper pasts) and Chungkukjang for their possible genotoxicity. The genotoxicity of 20 kGy-irradiated samples was evaluated by Salmonella typhimurium reversion assay. The Salmonella tester strains included TA98, TA100, TA1535 and TA1537 in the absence and presence of an exogenous metabolizing system (59 mix). All samples were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537. The results indicated that 20 kGy of gamma irradiation on water-soluble fraction of Kanjang, Doenjang, Kochujang and Chungkukjang were not shown mutagenicity.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.39-46
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• 2005

Background : Even though it has been suggested that low-colony, scotochromogen nontuberculous mycobacteria (NTM) are usually contaminants and not true pathogens, evidence for this hypothesis has not been provided. This study investigated the colony characteristics, organism identification, and clinical significance of low-colony scotochromogen. Methods : The laboratory cultured 6,898 respiratory clinical specimens for an examination of mycobacteria over a three-month period. A low-colony count was arbitrarily defined as ${\leq}20$ colonies. This study analyzed the recovery rate of the mycobacteria, the number of colonies and their gross characteristics, and their clinical significance. PCR-restriction fragment length polymorphism analysis was carried out to identify the NTM species. NTM pulmonary disease was defined according to the American Thoracic Society. Results : A total of 6,898 respiratory specimens for mycobacterium were cultured. Of these, 263 (3.8%) grew NTM, and 382 (5.5%) grew M. tuberculosis. Of the 263 cultured NTM specimens, 124 (47.1%) were scotochromogens. The smear-positive rate was significantly lower in these scotochromogens (4.8%) than in the non-scotochromogens (23.7%) (p<0.05). The most common isolates were M. gordonae (83/102, 81.4%) in the scotochromogens, and MAC (52/121, 43.0%) in the non-scotochromogens. Even though three out of 113 patients with a low-colony scotochromogen has been diagnosed with NTM pulmonary disease, the isolated scotochromogen was not considered to be the cause of the NTM disease but was just a contaminant. Conclusion : In this study, the most common isolate of a low-colony count scotochromogen was M. gordonae, which appeared to be contaminants and not true pathogens. Greater efforts in the quality control of a mycobacterium laboratory are needed in cases where there is a high recovery rate of low-colony count scotochromogen.

• The Korean Journal of Applied Statistics
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• v.5 no.2
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• pp.211-227
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• 1992

In this paper we consider the definition and mathematical properties of similarity or dissimilarity which have often used in clust analysis, and we apply a hierarchical agglomerative cluster algorithm to a dissimilarity metrx generated by these distance. Here we investigate the effect of relation between distance function and cluster algorithm on the retrieval ability of natural clusters. We present an empirical results for qualitative data as well as quantitative data.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1351-1356
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• 2003

Antibacterial activities of Chinese cabbage kimchi juice were determined against Staphylococcus aureus ATCC 6538p, Salmonella enteritidis ATCC 13076, Vibrio parahaemolyticus ATCC 17802 and Enterobater cloacae ATCC 13047. It was found out that 2% content of Chinese cabbage kimchi juice reduced the colony numbers of Salmonella enteritidis ATCC 13076, Enterobater cloacae ATCC 13047, Staphylococcus aureus ATCC 6538p and Vibrio parahemolyticus ATCC 17802 by 63%, 72%, 76% and 90%, respectively. 6% content of Chinese cabbage kimchi Juice completly inactivated Vibrio parahaemolyticus. But at the same content (6%) of Chinese cabbage kimchi juice, colony number of Salmonella enteritidis ATCC 13076 Enterobater cloacae ATCC 13047 and Staphylococcus aureus ATCC 6538p were reduced to 11%, 10% & 9%, respectively.10% Chinese cabbage kimchi juice had 100% inhibitory effect on all test bacteria. Therefore, Chinese cabbage kimchi has effective antibacterial activities against Staphylococcus aureus ATCC 6538p, Salmonella enteritidis ATCC 13076 Vibrio parahaemolyticus ATCC 17802 and Enterobacter cloacae ATCC 13047.

• Journal of Conservation Science
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• v.24
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• pp.75-83
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• 2008

In order to assess antifungal activity of a wooden storage box, which was made of Paulownia tomentosa and used for keeping ancient documents, antifungal activity of volatile organic compounds emitted from the box was investigated along with qualitative analysis on major substances of the compounds. After collecting floating microorganisms inside air tester, the fungal activity was assessed by counting the number of colonies growing on TSA media. Compared to the control which collected 85 colonies from outdoor, 72 colonies were observed showing reduction rate of 14.82%. Through GC/MS and TDS system analysis, limonene was detected from the volatile organic compounds as characteristic features. When the fungal activity was assessed through fumigation by adding natural biocide BI and BII containing eugenol and anethole as major substances, both biocides showed a strong fungal activity with respectively 92.6%(inside the box) and 99.9%(outdoor) of reduction rate. Although these results didn't clarify antifungal activity of the volatile organic compounds emitted from the Paulownia-wood storage box and their functional components, it was at least confirmed that there is application possibility of natural biocide to use for preservation of ancient documents with increased efficiency in controlling pests of wooden storage boxes.

• Korean journal of food and cookery science
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• v.17 no.6
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• pp.617-624
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• 2001

Gamma irradiation (1-10 kGy) was applied to chicken for the evaluation of their microbiological safety and possible genotoxicity. In 3 kGy-irradiated sample, the growth of psychrophile was inhibited about 1.5 log cycles and no cells were recovered in total microbial counts. All kinds of contaminated microorganism were sterilized by 7 kGy-irradiation. Also, irradiation followed by freeze-storage at the same time was very effective in inhibiting bacterial growth. The genotoxicity of 10 kGy-irradiated chicken was evaluated by Salmonella Typhimurium reversion assay and in vivo micronucleus assay using mouse bone marrow cells. The results were negative in the bacterial reversion assay with S. Typhimurium TA98, TA100, TA1535, and TA1539. Clastogenic effects were not shown in vivo mouse micronucleus assay at 10 kGy-dose tested.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.375-382
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• 2010

The purpose of this study was to evaluate suppression of Streptococcus mutans(S. mutans) colonization by long-term xylitol consumption among pregnant women who can easily get bad oral hygiene status during pregnancy and breast feeding. Participants were voluntarily recruited for a pregnant women's oral health prevention program, classified into two groups(a control and a xylitol group), and then followed for 18 months. Stimulated whole saliva was collected in the afternoon(1:00-3:00 p.m.) at baseline, 6 months, 12months, and 18 months. Information regarding oral health behavior(tooth brushing frequency and regular dental visits) was obtained via a questionnaire. S. mutans counts of the xylitol group decreased considerably between baseline and the re-examinations at 6, 12, and 18 months. Although the S. mutans counts decreased for all time points compared to baseline in the control group, these differences did not reach significance except 18 months. Regular chewing of xylitol gum over a long period may lead to decrease the colony counts of S. mutans.