• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.493-503
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• 2021

The study was designed to analyze raw and auxiliary materials of Korean traditional cookies such as Yugwa and Gangjeong, equipment and tools, personal hygiene of workers and microbial contamination of materials by each manufacturing process. In addition, it looked at washing method for reducing microorganisms at the site and reduction effect of microorganisms by frequency in the manufacturing processes of Yugwa. In the process of producing Korean traditional cookies, the level of total aerobic bacteria (TAB) in popped rice was 1.2 Log CFU/g and the level of TAB in finished products increased to 3.7 Log CFU/g. In the process of producing Yugwa, the level of TAB increased to a maximum of 6.5 Log CFU/g in the soaking process but decreased to 1.3 Log CFU/g in the frying process. However, the level of TAB increased again to 1.3 Log CFU/g in finished products that proves its recontamination. It is estimated that he manufacturing process causes cross-contamination that comes from the work tools, equipment or workers. In particular, the spatula, one of the work tools, was found to have 4.4 Log CFU/g of aerobic bacteria and 4.2 Log CFU/g of colon bacillus that show they are highly contaminated. In the soaking process of Yugwa that lasts seven days, the level of TAB was a maximum of 10 Log CFU/g and the level of total colon bacillus was 6.8 Log CFU/g. When compared with washing methods, using hands and tools or running water, it is confirmed that the level of both TAB and total colon bacillus decreased to 5.0 Log CFU/g and 2.8 Log CFU/g respectively when hands were washed with running water 10 times. The above result shows that it's required for workers to wash their hands as well as wash and disinfect work tools and equipment in the process of producing Korean traditional cookies at small-scale companies. In addition, to reduce the level of microbial contamination in finished products, workers are required to apply their reduction method at the site.

• Journal of dental hygiene science
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• v.9 no.3
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• pp.327-338
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• 2009

This study was to develop an instrument for multidimensional measurement of Korean scaling fear (KSF)-1.0 and analyze related factors. A sample of 720 subjects(scaling patients and community people) was studied in Daegu city from November in 2008 to March in 2009. Authors first conceptualized the KSF, item generation, item reduction, and questionnaire formatting were performed in the stage of the development. Item descriptive, missing%, item internal consistency, and item discriminant validity were analyzed in the item-level, also descriptive, floor and ceiling effect were analyzed in the scale-level. Cronbach's alpha, test-retest, inter-dimension correlations, and factor analysis were performed to evaluate the validity and reliability in the new instrument. Confirmative factor analysis was did to evaluate the fit of model. The results for item-level and scale-level were acceptable except item discriminant validity. The reliability for 0.92~0.96 of corelation coefficient range(Cronbach's alpha 0.96~0.98) was high in the test-retest, and there was no significant difference in paired t-test. Item internal consistency(range of pearson corelation coefficient 0.39~0.95) was also high. The result of explanatory factor analysis was the same as the intended dimension structure, also confirmatory factor analysis results revealed that the dimensional structure model were fined well in the evaluation of model fit($x^2$= 1245.66, df=146, p=0.0000; GFI=0.85; AGFI=0.80; RMSEA=0.10). Factors related to KSF by multiple regression were gender($\beta$=0.28, p=0.0004) and teeth brush method($\beta$=-0.15, p=0.0053) in scaling patients, also gender($\beta$=0.25, p=0.0002), educational level($\beta$=0.14, p=0.0155), teeth brush method($\beta$=-0.09, p=0.0229) and time of daily work out($\beta$=-0.10, p=0.0055) were significantly associated with KSF in no scaling group. In conclusion, The results of this study reveal that the new developed measurement scale was reliable and val id instrument for measuring the KSF in dental hygiene patients and community people. We recommend that further research should develop more the instrument for the Korean scaling fear.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.353-364
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• 2020

Recently in Korea, soybean harvesting has been delayed due to rainfall during the harvesting season, resulting in a reduction in yield and seed quality. This study was conducted to analyze the changes in yield and seed quality during delayed harvest with rainfall treatment using different harvesting methods, including field harvesting and polyethylene film covering after cutting fully-matured soybean plants (PE covering after cutting), with two major Korean soybean cultivars (Glycine max L), Pungsannamulkong and Daewonkong. The shattering rate of Pungsannamulkong, which is higher than that of Daewonkong, increased up to 41.8% when the harvest was delayed for 40 days without rainfall treatment by harvesting with PE covering after cutting. The weight of 100 seeds tended to decrease slightly as harvesting was delayed. When Daewonkong was harvested using the PE covering after cutting method with rainfall treatment, the yield decreased to the lowest level with a 0.8 kg ha^-1 daily reduction rate. Pungsannamulkong showed the lowest yield when harvested using PE covering after cutting without rainfall treatment with a 3.4 kg ha^-1 daily reduction rate. The infected seed rate increased according to the harvest delay in both cultivars, and significant differences were observed according to rainfall treatment and harvesting method. The germination rate was maintained above 95% even after 40 days of delayed harvest if there was no rainfall treatment. However, with rainfall treatment, the germination rate was significantly lowered as harvesting time was delayed. In the field harvesting with rainfall treatment, the germination rate decreased to 77.2% for Daewonkong and 76.5% for Pungsannamulkong after 40 days of harvest delay. For the 100-seed weight, effects of individual treatments and interactions between treatments were not observed. In contrast, the effect of interactions between treatments on the shattering rate was significant in both cultivars, indicating that the shattering rate had the greatest impact on the yield changes during delayed harvest.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.1
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• pp.42-46
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• 2016

The radioactive iodine ($^{131}I$) presents in the environment through the excrete process of nuclear medicine patients. In the detecting of low level of $^{131}I$ in the public water, the counting uncertainty has an effect on the accuracy and reliability of detecting $^{131}I$ radioactivity concentration. In this study, the contribution of sample amount, radioactivity concentration and counting time to the uncertainty was investigated in the case of public water sample. Sampling points are public water and the effluents of a sewage treatment plant at Sapkyocheon stream, Geumgang river. In each point, 1, 10 and 20 L of liquid samples were collected and prepared by evaporation method. The HPGe (High Purity Germanium) detector was used to detect and analyze emitted gamma-ray from samples. The radioactivity concentration of $^{131}I$ were in the range of 0.03 to 1.8 Bq/L. The comparison of the counting uncertainty of the sample amount, 1 L sample is unable to verify the existence of the $^{131}I$ under 0.5 Bq/L radioactivity concentration. Considering the short half-life of $^{131}I$ (8.03 days), a method for measuring 1 L sample was used. However comparing the detecting and preparing time of 1, 10 L respectively, detecting 10 L sample would be an appropriate method to distinguish $^{131}I$ concentration in the public water.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.4
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• pp.295-305
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• 2001

Protein kinase C (PKC) is known to play a pivotal role in neoplastic transformation cells and its high expression is often found in a variety of types of tumors including oral cancer. While PKC is associated with the altered signal transduction pathway of the tumor cells, it is still unclear which isoform is involved in the carcinogenesis process. Since the cellular distributions and the roles of PKC are isoform-specific, it is very important to identify the specific target molecules to improve our understanding of the carcinogenesis processes. Thus, the present study attempted to perform chemical carcinogen-induced neoplastic transformation of human epithelial cells and analyze the specific isoform of PKCs involved in the cellular transformation. The study analyzed overall PKC responses upon MNNG(N-Methyl-N'-nitro-N-nitroso guanidine) exposure with [$^3H$] PDBu binding assay. PKC translocation was observed at high doses of MNNG treatment in the presence of extracellular calcium. Such effects were not observed in the absence of extracellular calcium. Translocational effects with exposure of MNNG was further enhanced in the presence of hydrocortisone. The result suggests that the type of PKC involved may be $Ca^{2+}$-dependent classical isoform and steroid hormone enhances PKC activation. Among cPKC isoforms examined, only $PKC-{\alpha}$ and r showed significant translocation of protein levels from cytosolic fraction to membrane fraction, as analyzed by immunoblot. $PKC-{\varepsilon}$ in nPKC class showed an inch·eased translocation, but other forms in this class did not show the effect. None of isoforms in aPKC class was affected by MNNG treatment. The study demonstrated that there was a certain specificity in the patterns of isoform induction follwong chemical carcinogen exposure and helped identify all the types of PKC isoforms expressed in human epithelial cells. It was revealed that PKC isoforms were activated in an early resonse to chemical carcinogen, suggesting that PKC be associated with carcinogenesis process from an early stage in this particular cell system. The study will contribute to improving our understanding of chemical-induced carcinogenesis in human cells and may provide a scientific basis to introduce the specific PKC inhibitors as an anticancer drug of epithelial cell-origin cancers including oral cancer.

• The Korean Journal of Ecology
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• v.25 no.3 s.107
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• pp.163-170
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• 2002

In order to analyze the life cycle of A. artemisiifolia var. elatior dormancy and some environmental factors inducing germination of the seeds were examined. The results were as follows : Dormancy of fertile seeds was broken in part within a month after seed collection in case of adequate moisture and alternating temperature was also effective in breaking dormancy. The temperature range, which allow germination was $12^{\circ}C{\sim}32^{\circ}C$. Optimum temperature for germination was $24^{\circ}C$. The seed of A. artemisiifolia var. elatior was light-independent. The difference of storage period appeared to have no particular effect on the viability of seeds at any time during the 9-month storage period. In the increasing temperature(IT) regime, A. artemisiifolia var. elatior seeds started to germinate at $16^{\circ}C$, showing the higher temperature the greater germination rate : the final germination percentage was 99.34%. On the other hand, in the decresing temperature(DT) regime, seeds began to germinate at $20^{\circ}C$ with the 1.34% germination. An induced dormancy occurred at $12^{\circ}C$ making the 5.34% final germination in the DT regime. Low temperature was more effective to break dormancy than higher temperature. Seeds of A. artemisiifolia var. elatior seems to be germinated in mid to late autumn or germination delayed until following spring. The above results suggest these variation of germination response in diverse environmental factors seems to be a physiological strategy to maintain their existence and to reproduce in the extreme thermal variation.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.275-283
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• 2007

This study was carried out to: (1) analyze structural stability of representative rain-sheltering greenhouses for large-grain grapevine cultivation with widths of 3.6 m and 5 m in case of using the existing pipe for agriculture; (2) present the optimum specification of pipes in the greenhouse with a width of 5 m under the condition of using the pipe of which ultimate strength has been above $400N{\cdot}mm^{-2}$; (3) evaluate stability and also present the optimum specification of pipes as eaves height was augmented. The above analyses were done for greenhouses with roof vents and also with a main-column interval of 3 m and a rafter interval of 60 cm. First, the existing 3.6 m greenhouse with a rafter of ${\Phi}25.4{\times}1.5t@600$ was stable far a snow-depth of 35 cm but unstable for a wind velocity of $35m{\cdot}s^{-1}$. Meanwhile the existing 5 m greenhouse with the same rafter was not stable for a wind velocity of $335m{\cdot}s^{-1}$ as well as a snow-depth of 35 cm. This meant that existing greenhouses had to be reinforced to secure stability. Second, the specification of pipes, especially rafter, could be classified as two cases. One had a structural stability at a safe wind velocity of $35m{\cdot}s^{-1}$ and a safe snow-depth of 40 cm for which stability the rafter had to be ${\Phi}31.8{\times}1.5t@600$, and the other had a stability at $30m{\cdot}s^{-1}-35cm$ at the specification of rafter ${\Phi}25.4{\times}1.5t@600$. Finally, eaves height had a significant effect on safe wind velocity. But it had little influence on safe snow-depth. The results showed that the specification of side-wall pipes had to be reinforced for the safe side velocity accord-ing to the increment of eaves height and similarly the specification of fore-end post far the safe fore-end velocity.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.382-394
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• 2008

The objective of this study was to analyze temporal trends of water chemistry and spatial heterogeneity between the dam site (Daecheong Reservoir, S1) and the downstream (S2$\sim$S4) using water quality dataset (obtained from the Ministry of Environment, Korea) during 2000$\sim$2007. Water quality, based on eight physical and chemical parameters, varied largely depending on the years, sampling sites, and the discharge volume. Conductivity and nutrients (TN and TP) showed a decreasing trend in the downstream (S4) rather than the dam site during the monsoon. Spatial variation increased toward downstream (S4) from Daecheong Reservoir (S1). Also, BOD and COD increased toward downstream. Because of input of nutrient and pollutant nearby S1, lentic ecosystem in monsoon, BOD and COD were slightly increased. whereas relatively decreased in S4, lotic ecosystem in monsoon, by dilution effect of nutrient and pollutant by discharge from upper dam, S1. Spatial variation of SS increased toward downstream (S4) by the side of Daecheong Reservoir (S1). Based on the dataset, efficient water quality management in the point source tributary streams is required for better water quality of downstream. Monthly characteristics of DO showed the lowest value in the monsoon that tend to increase water temperature. DO was lowest in October at S1 because turbid water, input to the Daecheong Reservoir in the monsoon affect to the postmonsoon period. In contrast, water temperature increased toward summer monsoon, in spite of some differences showed between S1 and S4 environment. Overall, the characteristics of water quality in downstream region have close correlation with discharge amount of Daecheong Reservoir. Thus, those characteristics can explain that discharge control of upper dam mainly affect to the water quality variation in downstream reach.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.110-123
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• 2014

Recently, having neighborhood parks within walking distance has grown in importance. The purpose of this study is to analyze the effect of user satisfaction with neighborhood parks within walking distance considering interior and exterior environments. To do so, a field survey and GIS were conducted to construct data which were then compared with result of the analysed environment. Finally, amultiple regression analysis was conducted to confirm impact on user satisfaction of environment. By summarizing the study results, it was found that users of Hwarang Park exhibited a high level of satisfaction with 'park facilities' and 'safety of park use'. In the case of Gwanum Park, users exhibited a high level of satisfaction with 'green space' and 'amount of shade'. On the contrary, two park users exhibited low levels of satisfaction with 'facilities for children' and 'various attractions' within the parks. The pedestrian environment of Hwarang Park was rated higher than Gwanum Park within the park service area. User satisfaction was also rated higher than for Gwanum Park. However, two park users exhibited low levels of satisfaction with 'various attractions' within the pedestrian environment. From the result regression analysis of the total satisfaction factors, 'environment of access route', 'park facilities' and 'space for walking' positively influenced park use satisfaction. It was found that improvement of the pedestrian environment would be more effective than the improvement of the internal environment on Hwarang Park. This study investigated correlation with the access road environment as well as the interior environment of the parks. The results of this research will be used to improve accessibility and availability for neighborhood parks within walking distance.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.43-71
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• 1999

This research is an experimental work of developing a construction material using municipal wastewater sludge as liner and cover materials for waste disposal landfill. Weathered granite soil and flyash, produced as a by-product in the power plant, were used as the primary additives to improve geotechnical engineering properties of sludge. For secondary additives, bentonite and cement were mixed with sludge to decrease the permeability and to increase the shear strength, respectively. Various laboratory test required to evaluate the design criteria for liner and cover materials, were carried out by changing the mixing ratio of sludge with the additives. Basic soil properties such as specific gravity, grain size distribution, liquid and plastic limits were measured to analyze their effects on permeability, compaction, compressibility and shear strength properties of mixtures. Laboratory compaction tests were conducted to find the maximum dry densities and the optimum moisture contents of mixtures, and their effectiveness of compaction in field was consequently evaluated. Permeability tests of variable heads with compacted samples, and the stress-controlled consolidation tests with measuring permeabilities of samples during consolidation process were performed to obtain permeability, and to find the compressibility as well as consolidational coefficients of mixtures, respectively. To evaluate the long term stability of sludges, creep tests were also conducted in parallel with permeability tests of variable heads. On the other hand, for the compacted sludge decomposed for a month, permeability tests were carried out to investigate the effect of decomposition of organic matters in sludges on its permeability. Direct shear tests were performed to evaluate the shear strength parameters of mixed sludge with weathered granite, flyash and bentonite. For the mixture of sludge with cement, unconfined compression tests were carried out to find their strength with varying mixing ratio and curing time. On the other hand, CBR tests for compacted specimen were also conducted to evaluate the trafficability of mixtures. Various test results with mixtures were assessed to evaluate whether their properties meet the requirements as liner and cover materials in waste disposal landfill.