• Journal of Korean Foot and Ankle Society
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• v.17 no.2
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• pp.106-114
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• 2013

Purpose: Posteroanterior screw fixation is biomechanically stronger than anteroposterior screw fixation. However, there are few literature about the correlation between clinical results and more strength by posteroanterior fixation. This study was performed to evaluate the clinical outcomes of the accelerated rehabilitation following anterior open reduction and posterior percutaneous screw fixation for displaced talar neck fractures. Materials and Methods: Eighteen cases were followed up for more than 1 year after posteroanterior fixation using headless compression screw for talar neck fractures. The clinical evaluation was performed according to American Orthopaedic Foot and Ankle Society (AOFAS) score and Hawkins criteria. As radiographic evaluation, the degree of fracture displacement, period to union, and occurrence rate of complications such as avascular necrosis through MRI were measured. Results: The AOFAS score was average 90.4 points at the last follow-up. There were 7 excellent, 9 good, and 2 fair results according to the Hawkins criteria. Therefore, 16 cases(88.8%) achieved satisfactory results. The degree of fracture displacement had improved significantly from preoperative average 5.6 mm to 1.2 mm immediate postoperatively, and maintained to 1.1mm at the last follow-up. All cases achieved bone union, and the period to union was average 12.4 weeks. There were 3 cases of avascular necrosis of talar body and 2 cases of post-traumatic arthritis. Conclusion: Anterior open reduction and posterior percutaneous headless screw fixation seems to be an effective surgical method for displaced talar neck fractures, because of the possibility of accurate restoration of articular surface, fixation strength enough to early rehabilitation, and needlessness of hardware removal.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.248-256
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• 2020

This study aimed to evaluate the effects of national dental screening for children in Korea in the aspects of prevention of dental caries, the number of treatments related to dental caries, and cost of dental care. The study used the national cohort data on children health screening provided by National Health Insurance Service, and analyzed 32,937 1st dental screening, 22,608 2nd dental screening, 13,708 3rd dental screening, and 241,043 cases from the dental care of 27,944 children born in year 2008 and 2009. The decayed-filled teeth index and decayed-filled person rate, calculated from the results of the 2nd and 3rd dental screening, decreased as the number of preceding dental screening increased. Glass ionomer and amalgam restoration, pulp treatment of primary teeth and extraction of primary canine and molar were shown to decrease as the number of examined dental screening increased, and the total cost of dental care covered by national health insurance also decreased as the number of dental screening increased. In conclusion, national dental screening for children is an efficient and economical oral health care method that prevents dental caries and lowers the possibility of dental caries related treatment, thereby reducing cost of dental care.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.110-123
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• 2016

In order to obtain scientific information for the conservation of Utricularia japonica Makino, rare plant species, we investigated life history, phenology, growth and distribution in the east coastal region of Korea. Seven habitats of U. japonica were confirmed in this study. Turion of U. japonica rests overwinter at the bottom and ripens at the water surface and then usually germinate and sprout when the water warms in spring. A single shoot grown from turion divided into several shoots. Shoot decomposition started in October and formed a new turion at the end of the decomposed shoot. Flowering period was from early July to late October. Percentage of flowering ramets was significantly low as 6.3%. U. japonica showed the fastest growth rate from April to July, the maximum growth in August and the highest biomass in October. U. japonica tended to be concentrated in larger ramets in the water depth of 50 cm~150 cm in Cheonjin lake. The main factors affecting the growth of U. japonica were water temperature and turbidity. The establishment and growth of U. japonica in Cheonjin lake were determined by responses to water temperature with seasonal change and to light conditions caused by the different plants. These conditions affect the temporal and spatial distribution of U. japonica and population change. The findings of this study would be helpful to provide the basic information needed for the conservation and restoration of U. japonica.

• Korean Journal of Plant Resources
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• v.33 no.4
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• pp.303-310
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• 2020

This study was conducted on propagation use for conservation scheme of a threatened plant; Wikstroemia ganpi (Sieb. et Zucc.) Maxim(Geomundo false ohelo). The seed propagation was showed higher (95%) in storage and lower values in ground and cutting. Softwood cutting was higher than hardwood cutting and it was possessing higher ratio of rooting that increase concentration of IBA and NAA. It was determined that for Geomundo false ohelo seedling was effective than cutting. In-situ and ex-situ conservation and restoration of substitute habitats of Geomundo false ohelo is therefore necessary due to human trampling in the habitats, damage, natural selection, loss and suppression.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.3
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• pp.224-234
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• 2007

This study aimed to examine the harmful effects of Mn and Fe, which may be generated as dust or fume in the industrial sites, on the body and genital organs by their inhalation. It is intended to find the characteristics and differences of the hazardousness by inhaling a single and the mixed materials of Mn and Fe. Male F344 rats were divided into the control group and 3 exposed groups on the basis of the test material compound (Mn $1.5mg/m^3$, Mn 1.5 and Fe $3.0mg/m^3$, Fe $3.0mg/m^3$). The 4 groups were divided into 4 subgroups again on the basis of the exposure period (4 and 13 weeks) and the recovery period (4 and 13 weeks). The exposure condition was 6 hours a day, 5 days a week for the whole body. Clinical tests including changes in weight and feed rate, blood biochemical test, motility change, changes in the number and the amount of spermatozoon (sperm count), daily sperm production (DSP), deformity test of spermatozoon and changes in the accumulation of Mn and Fe in blood and internal organs were performed. Motility was reduced by Mn exposure. Especially, the effect of Mn was exposure period responsible. By mixing with Fe, no significant change in motility Mn and Fe accumulation in organs was observed. Sperm count and daily sperm production (DSP) were decreased by Mn. Additional effect like the reduction of sperm count and DSP, and delayed restoration of sperm count and DSP during the recovery period were observed in the mixed exposure group. These results indicate that Mn and Fe may affect the motility reduced and has male reproductive toxicity. Mixed exposure of Mn and Fe lead to synergic effects on the male reproductive toxicity.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.3
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• pp.183-190
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• 2014

Since Scenic Sites, heritages to protect the value of landscapes, include valleys and mountains, the cultural heritage protection zones and historical and cultural environments preservation districts are designated extensively. So the landscape protection effects of the designation of scenic sites should be examined. Accordingly, the purpose of this research is to present the methods of efficient institution of district for landscape protection of scenic sites. As the research subject, Cheongamjeong Pavilion and Seokcheongyegok Valley in Bonghwa (Scenic Site No. 60), which has the highest designation rate, was selected. The results of this research using the cumulative visibility technique of GIS are as follows. First, the method of selecting the viewpoint by preparing the reverse cumulative visibility from important landscape resources of the valley was presented. The reverse cumulative visibility can be utilized for rational selection of the viewpoint with regard to scenic sites. Second, the landscape analysis method in consideration of human viewing angle and the visibility of the background of landscape resources was developed. Third, the hierarchical landscape protection method of scenic sites utilizing cumulative visibility was presented. Fourth, it was established through on-site inspections that the method of institution of district is the practical method.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.9
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• pp.666-674
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• 2013

Physical disturbance, which induces a lack of flow rate, frequently occurs in freshwater ecosystem. Due to this, it is required to provide a new fish shelter to resolve. We installed a pilot scale test-bed to scrutinize the relationship between water level and the influence of fish shelter. The proposed ADP (artificial deep pool) is a fish shelter which composed of concrete materials. From the monitoring results in test-bed, it was observed that the population of fish was the highest at the 0.5 m in depth from the water level of experimental pond. But it was more appropriate for shallow water level (<0.3 m) to conserve the total number of fish by increasing the number per unit area despite of lower inner temperature and DO than outer environment. Therefore, inner of ADP was more efficient lentic system for fish to live due to higher WCS, OS, SS, and TS. In addition, there was a relative abundance of WCS fish species such as Acheilognathus koreensis (A. koreensis), Carassius carassius (C. carassius). Considered these results, it is suggested that ADP is appropriate to use for fish shelter and habitat for the fishes in lentic ecosystem.

• Journal of Environmental Impact Assessment
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• v.27 no.1
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• pp.56-72
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• 2018

North Korea has been in ecologically deficit state since 1966, despite of lack of energy and food resources. Trends of the Biocapacity (BC), the Ecological Footprint (EF), and the Ecological Deficit (ED) of North Korea were shown and five factors influencing on the Overshoot Rate (OSR) which is the ratio of the BC and the EF in North Korea was analyzed in this study. The five factors consist of two factors affecting to the EF and three factors affecting to the BC in North Korea. Two of the five factors are affecting to the EF those are population, the EF per capita (EFPC) which indicates the individual environmental consumption intensity, and three are affecting to the BC those are the land area, the yield factor, and the value multiplying the equivalence factor and the intertemporal yield factor. The EF has contributed more than the BC to the OSR. From 1966 to mid-1990s, the EFPC was the most contributing factor at about 60%, and after mid-1990s, population at about 40~60%. Contribution ratio of land area and the yield factor have increased after mid-1990s up to 15% and 18%, respectively. The BC of cropland which has decreased due to a decrease in productivity. In order to reduce the ED of North Korea, improvement of productivity of cropland and restoration of forest. Forest area has decreased significantly since 1990 in NK. And ways to solve the food shortage problem which influences on decrease of both productivity of cropland and forest area.

• Journal of Korea Water Resources Association
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• v.39 no.10 s.171
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• pp.881-890
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• 2006

Hydrological characteristics and urbanization effects in the Gap river catchment were investigated employing the SWAT model. The hydrological characteristics analysis showed that total runoff in the whole catchment from 2001 to 2004 consists of 44% of groundwater flow, 6% of lateral flow and 50% of surface flow under year 2000 landuse conditions. The analysis of urbanization effect using different landuse maps for year 1975 and 2000 indicated that although 5% increase in urbanized areas did not significantly impact on the total runoff in the whole catchment, a sub-basin where urbanized area increased by 32% over the past 30 years showed $68{\sim}73%$ decrease in groundwater flow and $22{\sim}66%$ increase in surface flow. It was found that urbanization decreased overall soil moisture and percolation rate except for some increase in soil moisture during dry season. Urbanization effect was found more sensitive during a dry year which has less rainfall and higher evapotranspiration than during a wet year. Therefore, from the results of this study we could infer increased flood damage during wet season and dried stream during dry season due to urbanization. To conclude, the results of this study can provide fundamental information to the eco-friendly restoration project for the three major rivers (Gap-cheon, Yudeung-cheon and Daejeon-cheon) in Daejeon Metropolitan City.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.231-242
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• 2011

Recently, the green spaces in the urban areas were greatly reduced due to urbanization and industrialization. As urban structures such as roads and buildings are built, the amount of impervious area within a watershed increases. High impervious surfaces are the common causes of high runoff volumes as the soil infiltration capacity decreases and the volume and rate of runoff increase thereby decreasing the groundwater recharge. These effects are causing many environmental problems, such as floods and droughts, climate change, heat island phenomenon, drying streams, etc. Most cities attempted to reduce sewer overflows by separating combined sewers, expanding treatment capacity or storage within the sewer system, or by replacing broken or decaying pipes. However, these practices can be enormously expensive than combined sewer overflows. Therefore, in order to improve these practices, alternative methods should be undertaken. A new approach termed as "Low Impact Development (LID)" technology is currently applied in developed countries around the world. The purpose of this study was to effectively manage runoff by adopting the LID techniques. Small Constructed Wetland(Horizontal Subsurface Flow, HSSF) Pilot-scale reactors were made in which monitoring and experiments were performed to investigate the efficiency of the system in removing pollutants from runoff. Based on the results of the Pilot-plant experiments, TSS, $COD_{Cr}$, TN, TP, Total Pb removal efficiency were 95, 82, 35, 91 and 57%, respectively. Most of the pollutants were reduced after passing the settling tank and the vertical filter media. The results of this study can contribute to the conservation of aquatic ecosystems and restoration of natural water cycle in the urban areas.