• Restorative Dentistry and Endodontics
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• v.43 no.4
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• pp.46.1-46.10
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• 2018

Objectives: This study was to evaluate the antibacterial effect of different instrumentation and irrigation techniques using confocal laser scanning microscopy (CLSM) after root canal inoculation with Enterococcus faecalis (E. faecalis). Materials and Methods: Mesiobuccal and mesiolingual canals of extracted mandibular molars were apically enlarged up to a size 25 hand K-file, then autoclaved and inoculated with E. faecalis. The samples were randomly divided into 4 main groups according to the system of instrumentation and irrigation: an XP-endo Shaper (XPS) combined with conventional irrigation (XPS/C) or an XP-endo Finisher (XPF) (XPS/XPF), and iRaCe combined with conventional irrigation (iRaCe/C) or combined with an XPF (iRaCe/XPF). A middle-third sample was taken from each group, and then the bacterial reduction was evaluated using CLSM at a depth of $50{\mu}m$ inside the dentinal tubules. The ratio of red fluorescence (dead cells) to green-and-red fluorescence (live and dead cells) represented the percentage of bacterial reduction. The data were then statistically analyzed using the Kruskal-Wallis test for comparisons across the groups and the Dunn test was used for pairwise comparisons. Results: The instrumentation and irrigation techniques had a significant effect on bacterial reduction (p < 0.05). The iRaCe/XPF group showed the strongest effect, followed by the XPS/XPF and XPS/C group, while the iRaCe/C group had the weakest effect. Conclusions: Combining iRaCe with XPF improved its bacterial reduction effect, while combining XPS with XPF did not yield a significant improvement in its ability to reduce bacteria at a depth of $50{\mu}m$ in the dentinal tubules.

• KCID journal
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• v.10 no.2
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• pp.36-42
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• 2003

According to development and urbanization of country, environment and ecosystem were ignored during the past thirty years. So that, canal which had been developed by concrete, is remained as the space where life can not alive any longer. Therefore, in thi

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.600-600
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• 2003

I. Objectives Effective endodontic obturation must provide a complete, three-dimensional filling of the root canal system, preventing the communication of fluids between root canal and surrounding periapical tissues. The objective of this study was to compare the apical leakage with or without the use of dentin adhesive system. II. Materials and Methods Forth extracted human teeth with single canals were decoronated. Root canals were instrumented using GT rotary files and Profile .04 file up to #40, 1mm short of the apex. After each instrumentation, copious irrigation with 5.25% sodium hypochlorite solution and confirmation of apical patency were performed.(omitted)

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.11.1-11.10
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• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.6
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• pp.63-77
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• 2006

The research aim is to classify biotope types of rural eco-villages designed by ministry of environment and analyze landscape ecological characteristics of them. This information would provide information on eco-villages' potential and specific needs to improve landscape ecological structure of eco-villages. Two eco-villages, designated by ministry of environment, in Yoocheon-ri and Sanduk-ri were selected and the landscape ecological metrics used in this study were Area, Shannon diversity index, Shape index, Distance index. The results are as follows. 1) There were five biotope types in large-scale classification, 13 biotope types m Sanduk-ri and 9 biotope types in Yoocheon-ri in middle-scale classification, 31 biotope types in Sanduk-ri and 24 biotope types in Yoocheon-ri in small-scale classification. 2) In the case of area, artificial biotope types, such as artificial forest, agricultural irrigation canal, wet paddy, dry paddy and residential area, covered more than 80% of total area. However, natural biotope types, such as natural forest, river, reservoir, covered just more than 10% of total area. In details, an orchard (26.69%) was the dominant biotope type, followed by artificial forest (19.10%) in Sanduk-ri and the first most abundant biotope type was artificial forest (49.71%), followed by wet paddy (15.95%) in Yoocheon-ri. 3) The result of Shannon diversity index indicated that Sanduk-ri (2.158) had more heterogeneity landscape, rather than Yoocheon-ri (2.051). 4) In the case of shape index, road (13.09) had more complex and irregular shape than either agricultural irrigation canal (3.35) or artificial forest (2.46) in Sanduk-ri. Road (6.52) was also the most irregular biotope shape, followed by river (5.70) and agricultural irrigation canal (4.78) in Yoocheon-ri. 5) Mean Nearest-neighbour Distance (MND) was smallest in wet paddy and dry paddy biotope types in the two study area, suggesting that these biotope types were concentrated within these study areas. From the result, this research suggested information to protect and improve biotopes of eco-villages in the landscape ecological terms. To achieve this improvement plan, there should be strong support by ministry of environment and local governments.

• Parasites, Hosts and Diseases
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• v.59 no.4
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• pp.427-432
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• 2021

The infection status of zoonotic trematode metacercariae (ZTM) was investigated in total 568 freshwater fishes (19 species) from the irrigation canal of Togyo-jeosuji (Reservoir) in Cheorwon-gun, Gangwon-do, the Republic of Korea for 3 years (2018-2020). All fishes were examined using the artificial digestion method. The metacercariae of Clonorchis sinensis (CsMc) were detected in 180 (43.8%) out of 411 fish of positive species, and their infection intensity was 38 per fish infected (PFI). Especially, in 2 fish species, i.e., Pseudorasbora parva and Puntungia herzi, the prevalence was 82.1% and 31.3%, and the infection intensity with CsMc was 88 and 290 PFI, respectively. Metagonimus spp. metacercariae (MsMc) were found in 403 (74.1%) out of 544 fish of positive species, and their infection intensity was 62 PFI. In the pale chub, Zacco platypus, the prevalence of MsMc was 98.6%, and their infection intensity was 144 PFI. Centrocestus armatus metacercariae were detected in 171 (38.9%) out of 440 fish of positive species, and their infection intensity was 1,844 PFI. Echinostoma spp. metacercariae were found in 94 (19.6%) out of 479 fish of positive species, and their infection intensity was 3 PFI. Metorchis orientalis metacercariae were detected in 43 (29.3%) out of 147 fish of positive species, and their infection intensity was 4 PFI. By the present study, it has been confirmed that some species of ZTM, including CsMc and MsMc, are prevalent in fishes from the irrigation canal of Togyo-jeosuji in Cheorwon-gun, Gangwon-do, Korea.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.2
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• pp.95-104
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• 1988

This study refers to the development of a hydrologic model simulating daily inflow and release rates for inigation reservoirs. A daily - based model is needed for adequate operation of an irrigation reservoir sufficing the water demand for paddy fields which is closely related to meteorological conditions. And the objective of this study is to develop a reservoir release rate model and then to calibrata the parameters. The release rates model considers daily water demands , water supply for transplanting, minmum release for maintaining canal flow, and maxirnun and regular flooding depth for determining effective rainfall on paddy fields. Each of the factors in the model was regarded as a lumped pararuter representing the average condition of a whole irrigated area. The water demand was estimated form the potential evapotranspiration by Penman method, the effective rainfall, and the infiltration on paddy fields. The release model was found to be capable of adequately simulating daily reservoir releases based on meteorological data.

• Current Research on Agriculture and Life Sciences
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• v.15
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• pp.39-46
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• 1997

In 1996, a cold-water damage occured in the paddy field at the downstream of the Umoon dam. To study the cause and the preventive measures of the cold-water damage a field study was performed during the growing season of 1997. Field measurements such as water temperatures at reservoir, irrigation canal and in the paddy field were made. As a result, there was no cold-water damage due to the right irrigation water management practice in 1997. The cold-water damage is possible to happen, however, and the preventive measures were provided.

• KCID journal
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• v.18 no.2
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• pp.142-160
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• 2011

This study was performed to apply the preventive management technique that is known for more economic and preventive for disaster than corrective technique to Repair & Improvement(R&I) Project policy of irrigational facilities. The appropriate periods of R&I Project had been driven to 40yrs, 24yrs, 27yrs, and 29yrs for reservoir, Pumping and drainage pumping station, Diversion weir and Irrigation & drainage canal respectively. The cost of R&I Project for 10 years had been estimated as 616.9 billion won per year including the 85 billion won for the project of 'Disaster prevention and Function continuity'. After the period of 'Improvement all at once', about 30yrs, 421.8 billion won was requested for 'Function continuity'.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.164-169
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• 2005

It is design and manufacture which the rake operated in and out of water. Also irrigation test result of several times, the flux inside the waterway collects 0.15m/s to case below the dirt which is accumulated in the rake 30kg, difficulty was to examine closely the thing, it followed hereupon and the grade in the agriculture waterway flux inside the cursor waterway was quick, or, with water level in dirt removal it established in the irrigation facility downstream it will be able to increase a flux, very the possibility of getting an efficient power it is it knew.