• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.166-173
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• 2006

This research has been performed to clarify the relationship between hydrogeochemistry and bacterial community structure in groundwater contaminated with landfill leachate. We collected and analyzed samples from 5 sites such as leachate (KSG1-12), treated leachate (KSG1-16), two contaminated groundwaters (KSG1-07 and KSG1-08) and non-contaminated groundwater (KSG1-13). pH was 8.83, 8.04, 6.87, 6.87 and 6.53 in order; redox potential (Eh) 108, 202, 47, 200 and 154 mV; electric conductivity (EC) 3710, 894, 1223, 559 and 169.9 $\mu$S/cm; suspended solids (SS) 86.45, 13.74, 4.18, 0.24 and 11.91 mg/L. In KSG01-12, the ion concentrations were higher especially in $Cl^-$ and $HCO_3^-$ than other sites. The concentrations of Fe, Mn and $SO_4^{2-}$ were higher In KSG1-07 than in KSG1-08, and vise versa in $NO_3^{2-}$. In the comparison of DGGE fingerprint patterns, the similarity was highest between KSG1-13 and KSG1-16 (57.2%), probably due to common properties like low or none contaminant concentrations. Otherwise KSG1-08 showed lowest similarities with KSG1-13 (25.8%) and KSG1-12 (27.6%), maybe because of the degree of contamination. The most dominant bacterial species in each site were involved in $\alpha$-Proteobacteria (55.6%) in KSG1-12, $\gamma$-Proteobacteria (50.0%) in KSG1-16, $\beta$-Proteobacteria (66.7%) in KSG1-07, $\gamma$-Proteobacteria (54.5%) in KSG1-08 and $\beta$-Proteobacteria (36.4%) in KSG1-13. These results indicate that the microbial community structure might be changed according to the flow of leachate in grounderwater, implying changes in concentrations of pollutants, available electron accepters and/or other environmental conditions.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.514-520
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• 2014

In this study, the production potential of alternative coagulant ($Al_2(SO_4)_3$ solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium (waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with $H_2SO_4$ solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of $Al_2O_3$ in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the $Al_2O_3$ content of 7~8% was produced under the optimal conditions such as $H_2SO_4$ purity of 50%, reaction temperature of $120^{\circ}C$, injection ratio of $H_2SO_4$ of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.148-159
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• 2012

The purpose of this study is to validate the effect of improvement such measures as fence installation or planting of bush and herbaceous plants taken from Pinus densiflora forest in Solbat Neighborhood Park in Seoul, which was damaged by stamping. The study was conducted in 2005 and 2010 in order to analyze changes in planting types, planting structure of Pinus densiflora forest, soil hardness, cross-sectional structure of soil, and physicochemical characteristics of soil. It was also measured by the growth of the branches and the diameter of Pinus densiflora, comparing before and after the improvement to study the effect of restoring Pinus densiflora forest damaged by stamping. When it comes to a change in planting type, Pinus densiflora forest without underlay was reduced from 48.5% in 2005 to 6.8% in 2010. Pinus densiflora forest with bush and herbaceous plants was increased dramatically from 7.4% to 46.8%. Regarding planting structure, in most area of the subject site, Pinus densiflora forest without under layer was transformed into the one with bush and herbaceous plants including Rhododendron mucronulatum, Rhododendron schippenbachii, Hemerocallis fulva, Aceriphyllum rossii, Hosta plantaginea growing in a wide area. The soil in the Solbat Neighborhood Park was very stiff with soil hardness of $54.8kg/cm^2$ in average. After the improvement efforts made in the Park in 2010, the soil hardness was mostly less than $4kg/cm^2$, being in a good condition with little influence on the growth of plants. When it comes to the cross-sectional structure of soil, litter layer didn't exist in 2005 because of stamping and the organic matter layer was only 1.0cm thick, which provided an unfavorable condition for plant growth. However, after improvement, litter layer was formed up to 3.0cm and thickness of the organic matter layer also went up to 1.5~8.0cm in 2010 because the damage from stamping was reduced. Concerning the physicochemical characteristic of soil, in 2005 soil showed pH 5.76~6.70, organic matter content 7.15~10.55%, and available phosphorus 9.38~26.47mg/kg, having no big problems as a soil environment for growth of Pinus densiflora. 15 trees of Pinus densiflora were selected to see branch growth and it was found that the branches tended to grow better after improvement. 70 trees of Pinus densiflora from various grades of soil hardness also were selected to identify changes of diameter growth. In most cases, it was analyzed that Pinus densiflora grew better after improvement. After conducting this study, it was validated that such measures as fence installation or planting of bush and herbaceous plants to restore Pinus densiflora Forest damaged by stamping were effective in improving growth of Pinus densiflora.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.238-245
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• 1998

The reasonable level of nitrogen fertilizer is a key factor to reduce environmental contamination as well as to increase crop yield and quality. The treatments are $N=42kg\;10a^{-1}$, $N=48kg\;10a^{-1}$, $N=54kg\;10a^{-1}$. $N=60kg\;10a^{-1}$. $N=72kg\;10a^{-1}$ and $N=150kg\;10a^{-1}$. Analytical results of yield and quality of tea leaves harvested the second time are summarized as follows: The soil of experimental field was higher in organic matter($49.9g\;kg^{-1}$) and available phosphate($937mg\;kg^{-1}$) compared to the general field but lower in pH(5.07) compared to the general field. When the amount of nitrogen fertilizer application was raised, the yield of tea leaves, the content of nitrogen, total free amino acids, caffeine and chlorophyll increased: however, the yield of tea leaves increased to excessive levels. On the other hand, the increased level of nitrogen fertilizer did not show any difference in the contents of vitamin C and tannin. Eleven kinds of amino acids were isolated from second harvested leaves of tea where the content of theanine occupied over 50%, and content of $665{\sim}763mg\;100g^{-1}$. The contents of fatty acids and catechin did not show correlation with application level of nitrogen fertilizer. The content of fatty acid was produced $1,742{\sim}2,643mg\;100g^{-1}$, and content of catechin was produced 12.47~13.54%. In scoring test, $N=60kg\;10a^{-1}$ treatment was 0.5~6.0 point higher compared to other treatments. Consequently, $N=60kg\;10a^{-1}$ is considered to be the best level of nitrogen fertilizer in terms of decreased environmental contamination as well as to increase crop yield and quality.

• Journal of The Korean Association For Science Education
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• v.24 no.3
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• pp.442-458
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• 2004

This study was conducted to develop a plan for a large-scale implementation of the Girl Friendly Science Program based on the results of analysis and investigation of its current pilot implementation, Girl Friendly Science Program materials, which was first developed in 1999 with the support from Ministry of Gender Equality, consist of 1) five theme-based units that are specifically targeted individual students' unique ability, aptitude, and career choice, and 2) differentiated learning materials for 7th through 10th grade female students. All the materials are available at the homepage (http://tes.or.kr/gfsp.cgi) of 'Teachers for Exciting Science(the organization of science teachers in Seoul area)'. Since the materials are well organized by topic and grade level and presented in both Korean word process document and html format, anyone can easily access to the materials for their own instructional use. Ever since its launch the number of visitors to the homepage has been constantly increasing. The evaluation results of the current pilot implementation of the materials that targeted individual students' ability and aptitude showed that it scored high in terms of its alignment to the original purpose, content, level, and effectiveness to implement in classrooms. However, its evaluation scores were low in terms of the convenience for teachers to guide the materials, and its organization and operation. The results also showed a significant change in students' perception of science, and students' positive experiences of science through various interdisciplinary activities. On the other hand, the evaluation of students' experiences with the materials showed that students' assessment about an activity was largely depending on a success or failure of their experiences. Overall, students' evaluation of activities scores were low for simple activities such as cutting off or pasting papers. According to students' achievement test results, differences between pre and post test scores in the Affective Domain was statistically significant (p<0.05), but not in Inquiry Domain. Based on teachers observations, numerous schools where have run this program reported that students' abilities to cooperate, discuss, observe and reason with evidences were improved. In order to implement this program in a larger scale, it is critical to have a strong support of teachers and induce them to change their teaching strategy through building a community of teachers and developing ongoing teacher professional development programs. Finally, there still remain strong needs to develop more programs, and actively discover and train more domestic woman scientists and engineers and collaborate with them to develop more educational materials for girls in all ages.

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.184-194
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• 1999

Backgrounds : The advent of penicillin has led to the marked reduction in the mortality from pneumococcal bacteremia, however, the mortality is still relatively high in this post-antibiotic era. Actually the prevalence of infection due to penicillin-resistant penumococci is increasing worldwide, and it is especially high in Korea due to irrelevant use of antibiotics. So, the high mortality of pneumococcal sepsis might be related to the emergence of penicillin-resistant strains, however, many other antibiotics, which eradicate pneumococci effectively, are available in these days. This has led us to suspect the role of penicillin-resistance in the high mortality rate. In this study, we evaluated the effect of penicillin resistance on the mortality of patients with penumococcal bacte remia. Methods: The study population consisted of 50 adult patients with penumococcal bacteremia who were admitted between Jan, 1990 and July, 1997. Medical records were analyzed retrospectively. Results: Most of the patients (96%) had underlying diseases. The most common local disease associated with pneumococcal bacteremia was pneumonia (42%), which was followed by spontaneous bacterial peritonitis (14%), cholangitis (10%), meningitis (8%), liver abscess (4%), pharyngotonsillitis (4%), sinusitis (2%) and cellulitis (2%). While the overall case-fatality rate in this study was 24%, it was higher when peumococcal bacteremia was associated with pneumonia (42%) or meningitis (50%). The rate of penicillin resistance was 40%, which was increased rapidly from 1991. The rate of penicillin resistance was significantly higher in patients with the history of recent antibiotics use and hospitalization within 3 months respectively. The clinical manifestations, that is, age, severity of underlying diseases, nosocomial infection, associated local diseases, and the presence of shock or acute renal failure were not statistically different between the patients with penicillin-resistant and -sensitive pneumococcal bacteremia. The mortality of patients infected with penicillin-resistant pneumococci was not statistically different from those with penicillin-sensitive pneumococcal bacteremia. Conclusion: Penicillin resistance is not associated with high mortality in adult patients with pneumococcal bacteremia. As the overall mortality is high, active penumococcal vaccination is recommended in patients with high risk of infection.

• Journal of Korean Academy of Nursing
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• v.20 no.3
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• pp.414-429
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• 1990

Numerous research reports have substantiated the role of stressful life events in relation to the onset of health changes. The relationship tends to hold across different age groups. Theoretically, adolescence has been considered a developmental crisis period of great stress, impoverished coping skills and high vulnerability to biological, social and psychological demands. The research problem addressed by this study was to examine the relationships between stressful life events and health symptom patterns, and the effect of two variables, coping and social, support, theoretically considered to mediate the relationship between stress and health symptoms in adolescents. The following five hypotheses were tested in this research : 1. Health symptoms are positively related to stressful life events in adolescents, 2. Health symptoms are negatively related to coping in adolescents, 3. Health symptoms are negatively related to social support in adolescents, 4. When coping is controlled, the relationship between health symptoms and stressful life events will decrease, and 5. When social support is controlled, the relationship between health symptoms and stressful life events will increase. The study subjects consisted of 1090 high school students of the metropolitan city of Seoul. The following sampling procedure was used : 1. Of the 169 high schools in nine school administrative districts in the city, a proportional sample of ten schools was selected. 2. One class from each of the freshman and sophomore was randomly selected and all the students who were in the sampled class were used as the study sample. The study was limited to freshman and sophomore adolescents, aged 15 to 18(mean＝16.6). Of the 1090 subjects 688(63%) were boys and 402(37%) were girls. An Adolescent Inventory of Stressful Life Events, a Health Symptom Questionnaire and an Adolescent Coping Inventory were adapted for this study. The Norbeck Social Support questionnaire was utilized to collect the data on perceived social support. Five high school teachers in the areas of school health and counselling reviewed the items of each questionnaire for content validity. A pilot study was undertaken to ascertain reliability. Fifty three high school students responded to the questionnaires and gave their opinions on the items. For stressful life events, health symptoms, coping, and social support, the Cronbach's alpha's on the study were .70, .94, .77, and .76, respectively. Research assistants attended all the sampled classes with the school proctor to explain the purpose and procedures of the study to the students. The questionnaires along with a ballpoint pen were distributed to the students who were asked to complete each item. The research assistants left the ballpoint pen with the students as a gift for their cooperation. An average of 50 minutes was required to complete the questionnaires. Using an SPSS, the first, three hypotheses were tested using Gamma, a measure of association for ordinal variables. Partial gamma was used to test the fourth and fifth hypotheses. Patterns of elaboration described by Babbie were selected to interpret the relationship of the three variable analyses. The significance of gamma was determined by Chisquare at a .05 level of significance. There was a positive relationship between health symptoms and stressful life events(Gamma＝.35, p＝.000). Thus the first hypothesis was supported. Unexpectedly, coping was positively related with health symptoms(Gamma＝.13, p＝.000). That is, the higher the coping levels, the greater number of health problems. The third hypothesis, the higher the level of social support, the fewer the health symptoms, was not accepted in this adolescent study group. When coping was controlled, under the condition of low coping the association between health symptoms and stressful life events increased significantly to a partial gamma of .39, and under the condition of high coping it was .30. According to the elaboration model, when one partial relationship is the same or greater than the original and the other is smaller, the control variable should be considered to be specifying the conditions. When social support was controlled the relationship between stressful life events and health symptoms increased under the condition of low social support, but with high social support, the relationship decreased. Both partial gamma were statistically significant at .05 level(.43 and .26 relatively). It can be interpreted that stressful life events are strongly and positively related to health symptoms under the condition of low social support, however this relationship can not be expected with high social support. Thus, the last two hypotheses were conditionally sustained. In this study, the relationships between stressful life events and health symptoms, and the specified me diating roles of coping and social support were found to have statistical interaction. This finding supports the theoretical position of this study. It suggests that stressful life events would create high susceptability to biological social and psychological health symptoms and coping and social support buffering the relationship between stressful life events and health symptom. The findings of this study have implications for nursing practice. When adolescents are confronted with non-developmental life events that are perceived as stressful, nurses should recognize the evidence of the stress-buffering effect of coping and social support on health symptoms and utilize the diverse sources of social support that are readily available to adolescents.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.145-153
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• 1999

Authors report the changes of the community structure and secondary succession after fire in Mt. Samma (333 m). Approximately six ha of the red pine (Pinus densiflora) forest and its floor vegetation were burned and cutted down. The vegetation and soil properties were investigated in the burned and unburned sites from April to October, 1998. The dominant species based on SDR₃ in the burned site were Lespedeza cyrtobotrya (96.87), Quercus serrata (77.90), Cyperus amuricus (46.22) and Miscanthus sinensis var. purpurascens (38.33), whereas the dominant species in the unburned site were Pinus densiflora (100.00) and Q. variabilis (66.10) at the tree layer, Q. serrata (100.00) and Zanthoxylum schinifolium (29.64) at the shrub layer., and Q. serrata (76.30) and M. sinensis var. purpurascens (72.84) at the herb layer. The biological spectra based on SDR₃ were Th-D₁-R/sub 5/-e for the burned and H (M)-D₁-R/sub 5/-e type for the unburned site, respectively. The index of similarity (CCs) between the burned and unburned sites was 0.41. The degree of succession (DS) were 609 for the burned and 1168 for the unburned site, respectively. The species diversity (H) and evenness indices (e) of the burned site were lower than those of the unburned site, but the dominance indices (C) was higher in the burned site. In the analysis of soil properties, pH, the content of NO₃/sup -/-N, available phosphrous, and exchangeable cations (K/sup +/, Ca/sup 2+/, Na/sup +/, Mg/sup 2+/) in the burned site were higher than those in the unburned site, whereas the contents of organic matter, total carbon, total nitrogen and NH₄/sup +/-N were lower in the burned site. The results show that dominant species in the burned site change from Miscanthus-Lespedeza→Lespedeza→Quercus and finally to Quercus forest, and the changes of soil properties also affect the early vegetational succession after fire.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.427-432
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• 2009

The aim of this study was to compare the shear-peel strength and the fracture site of 5 commercially available orthodontic band cements. One hundred molar bands were cemented to extracted human 3rd molars. The specimens were prepared in accordance with the manufacturer's instructions for each cement. After storage in a humidor at $37^{\circ}C$ for 24 hours, the shear debonding force was assessed for each specimen using an universal testing machine with crosshead speed of 2 mm/minute. Maximal failure stress was converted to mean shear-peel strength, MPa. The predominant site of band failure was recorded visually for all specimens as either at the band/cement or cement/enamel interface. Mean shear-peel strength of Ormco was the highest(2.44${\pm}$0.57), followed by Fuji $Ortho^{TM}$(2.24${\pm}$0.50), $Ketac-Cem^{TM}$(2.10${\pm}$0.57), 3M $Unitek^{TM}$(1.82${\pm}$0.43), $Band-Lok^{TM}$(1.73${\pm}$0.28). There were statistically significant differences between Ormco and $Band-Lok^{TM}$, Ormco and 3M $Unitek^{TM}$, and Fuji $Ortho^{TM}$ and $Band-Lok^{TM}$(p<0.05). The predominant site of bonding failure for bands cemented with the Ormco was at the band/cement interface, whereas bands cemented with Ultra $Band-Lok^{TM}$ failed predominantly at the enamel/cement interface. There was no significant difference among the other cements(Fuji $Ortho^{TM}$, 3M $Unitek^{TM}$, $Ketac-Cem^{TM}$).

• Journal of Korean Society of Forest Science
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• v.105 no.2
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• pp.247-252
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• 2016

This study was conducted to evaluate the technical efficiency of Annual Chestnut production in South Korea. In this study, technical efficiency is the maximum possible production for which a certain amount of costs is inputted. For analysis on the technical efficiency we used output-oriented BCC Model, and then we analyzed correlation among input costs, production, gross income, net income, and market price per unit in order to determine the cause of variation in the technical efficiency. As study materials, we used statistics for the forestry production costs for 7 years from 2008 to 2014. The study results showed that the maximum possible production and actual production in 2008, 2009, and 2010 were 1,568 kg, 1,745 kg, and 1,534 kg by hectares in the order which were the same values. Consequently, the technical efficiency of those was all evaluated as 1.00. On the other hand, actual production from 2011 to 2014 was 1,270 kg 1,047 kg, 1,258 kg, and 1,488 kg by hectares in the order and the maximum possible production was 1,524 kg, 1,467 kg, 1,635 kg, and 1,637 kg by hectares in the analysis. From those values, the technical efficiency was evaluated in the following order:0.83, 0.71, 0.75, 0.91. The lowest value of the technical efficiency was 0.71 in 2012, and the values of this increased gradually since 2013. It is indicated that the cause of variation in the technical efficiency was related to the relationship between production and market price, and there was a negative correlation with r = -0.821 (p<0.05). The level of maximum available production per unit area was between 1,488kg in lower limit and 1,745 kg in upper limit, and the average was turned out as 1,548 kg.