• Journal of Korean society of Dental Hygiene
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• v.7 no.4
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• pp.553-567
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• 2007

Migrant Worker are rapidly increasing in Korea since 1990. They are nowadays main sources of laborer groups engaging in medium-sized factories. The purpose of this study is to provide the basic information to establish proper oral health policy. Dental caries and periodontal disese are the most common disease that occur in the mouth. Periodontal disease is the most common disease in humans and the biggest reason for the loss of the teeth in the adult population. The CPITIN has been developed jontly by the international Dental Federation and the World Health Organization. CPITN is now an established index of level, of periodontal condition in populations for which specific intervention might be considered. This study was conducted to obtain the information regarding to CPITN of migrant workers located in Daegu, Questionaire survey was carried out for 289 workers from July 9 to August 8, 2006. Total survey was 289, 224 males and 65 females. The result was as follows: First, The number of nationality was 14. The first majority was China as 31.8% Among 14 nationalities were Cambodia 18.0%, Vietnam 12.8%, Sri Lanka 12.1%, Indonesia 7.3%, Nepal 4.2%, the other 13.8%, those who are aged from 20 to 29 were 43.9%, and salary from 1,000,000 won to 1,490,000 won 51.2%.(as for their residence, those who resided) over 3 years were 42.6% and not insured reached 68.5%. Second, more than 93.4% of the subjects need periodontal treatment, only 4.9% of non-smoker was health periodontal states, four times frequency of tooth brushing per a day was 16.7%. Third, 28.7% of migrant workers had experienced visit of dental clinic, and 22.9% had received treatment of decayed tooth. Fourth, It is difficult for them 65.1% of them to visit dental clinic in korea, the First was a communication problem and the second was time. Fifth, Most of them didn't have a oral health education but 85.1% of them said that they wish they attend oral health education. We conclude that the situation of migrant workers was very bad considering their working conditions, circumstances, and health condition. According to this study, more than 93.4% of the people need periodontal treatment. Besides they didn't have accurate knowledge about prevention of periodontal disease. Therefor our considering these facts, the policy of dental health by government should be established for migrant workers.

• Economic and Environmental Geology
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• v.53 no.3
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• pp.287-296
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• 2020

Mine Reclamation Project is being carried out with the aim of ensuring a sustainable green living and helping to develop eco-friendly mines by analyzing, removing and preventing the harmful factors. Mines developed during the japanese colonial period and mining boom period are still not repaired throughout the country, and from these scattered risks, public safety is worth pursuing as a top priority. The project that is close to public safety in the mine recalmation project is an emergency treatment, and the most widely used method is a filling method similar to the ground subsidence prevention. If dangerous mine cavity or tunnels are located in the mountains, charging with existing materials may not be possible, or unreasonable cases may occur, and new methods of technological development are required. Emergency actions should be carried out safely and efficiently to prevent the loss of precious people's lives on the hiking paths adjacent to dangerous mining sites. In these field conditions, urethane foam materials may be an alternative. In this study, the applicability of urethane foam materials in mining was reviewed through overseas cases. It was also tested on the appropriate depth of top soil for the protection of urethane foam materials through forest fire simulation test. The test result show that approximately 15cm of soil covering (recommended 20cm over) was suitable for maintaining the function of foam materials from forest fires.

• The Journal of Engineering Geology
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• v.22 no.4
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• pp.439-448
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• 2012

The aim of this study is to develop eco-friendly, fundamental technology for vegetative restoration of barren lands using green rehabilitation material, for the stabilization of abandoned mine debris slopes and depository slopes composed of rock fragments. It is expected that such methods would help to improve the negative view of artificial slopes that remain following mining activity, while also contributing to slope stabilization and prevention of the loss of rock fragments and the dispersion of tailings. We tested the tensile strength and tear strength of various materials, including commonly used natural coir material, natural fibers, and synthetic textile materials with enhanced durability. In conclusion, there is the possibility that natural coir can be used as an eco-friendly material in vegetation restoration, while its durability in natural conditions can be improved by controlling the degree of knot convolution and by antibacterial treatment against biodegradation.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.306-311
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• 2005

Lesch-Nyhan syndrome is a rare disorder of purine metabolism, first described in 1964. The incidence is estimated to be 1:100,000 birth. It is an X-linked recessive disorder in which affected males have a virtually complete deficiency of the enzyme hypoxanthine guanine phosphorybosyl transferase(HGPT). This enzyme deficiency gives rise to excessive uric acid production and consequent hyperuricemia. Lesch-Nyhan syndrome is clinically characterized by mental retardation, choreoathetosis, spastic cerebral palsy, and severe self-mutilation behavior. Patient with Lesch-Nyhan syndrome mostly bite their lip, tongue and finger. In severe cases, partial or total amputation of the lip and tongue is common. Self-inflicted bites are often further complicated by secondary infection to injuried site as well as pain. And tissue loss by biting results in esthetic problems. This report presents a Lesch-Nyhan syndrome patient with self-mutilation, who have a destruction of perioral tissue, especially the lower lip. He was treated successfully with soft mouthguard, psychological and pharmacological method.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.1
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• pp.1-10
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• 2013

Dental erosion is a complex disease of multifactorial etiology with high risk of loss of tooth structure, which still has not been appropriate interest. The aim of this study was to assess the prevalence and risk indicators of dental erosion in Korean school children. A cross-sectional survey was performed on 664 children aged 8~9 years. Data concerning gender, types of caregiver, dietary habits, oral hygiene habits and parental knowledge were obtained from a questionnaire, which was answered by the parents of the children. Association between erosion and the factors were statistically analyzed with chi-squared test and independent t-test at a significance level of 0.05. Dental erosion was present in 242 children. In carbonated drinks, dental erosion was significantly associated with preference, frequency of consumption and the ingestion method (p < 0.05). In fruit juices, dental erosion was significantly associated with preference and frequency of consumption (p < 0.05), but no significant associations were found with the ingestion method (p > 0.05). There were no significant associations between dental erosion and gender, type of caregiver, oral hygiene habits and parental knowledge (p > 0.05). In conclusion, it was considered that motivation to be followed by practice is important as well as education for prevention of dental erosion.

• Fire Science and Engineering
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• v.29 no.2
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• pp.73-78
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• 2015

Fire in the risk management subject belongs to high risk disaster which accompanies personnel and materiel loss. So, management of disaster and safety is required to include fire prevention activities, fire risk prediction and investment of safety management expense. Combustion toxicity is required by gas toxicity test (KS F 2271), to minimize human damage. In this study, gas toxicity test were experimented with regard to urethane sample (Depth 5~25 mm) to obtain basic data. Fire effluent exposing to experimental animal were analyzed by FT-IR (Fourier transform infrared spectroscopy). Combustion toxicity index Lethal Fractional Effective Dose ($L_{FED}$) of ISO 13344 was calculated. According to the result of calculating Lethal Concentration 50% ($LC_{50}$) based on $L_{FED}$, $LC_{50}$ of urethane sample containing certain level of fire load is confirmed as $118{\sim}129g/m^3$. Through this study, applicability of this method was confirmed for fire risk assessment. This method can provide information to predict human damage by toxicity combustion gas for securing safety.

• Journal of dental hygiene science
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• v.12 no.5
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• pp.469-476
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• 2012

The purpose of this study to grasp the effects of the stress coping method on the periodontal disease in order to provide raw data for the studies on the development of the training for effective stress copying method resulting in improvement in prevention, occurrence, and progression of periodontal disease. Data were collected from total of 326 subjects in their forties and fifties, during the period from March to October 2011. Using questionnaire and examination of periodontal health, and were analyzed using frequency, t-test, multivariate analysis of variance, multiple regression by SPSS ver. 19.0 (IBM Co., USA). The higher emotion-focused stress coping ($\beta$=0.341), the higher the gingival index, the higher the emotion-focused stress coping ($\beta$=0.239) the deeper the pocket depth, the higher the emotion-focused stress coping ($\beta$=0.158) the higher clinical attachment loss, showed statistically significant positive association. This study suggests that the dental clinic institute needs to implement education program including stress management and coping method improvement in order to prevent periodontal disease and make the occurrence and progression to be managed by professionals.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.82-90
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• 2010

This study examined the effect of adhesive tape supplemented with sodium fluoride on the prevention of dental erosion in vitro. Sound bovine tooth samples were selected and divided randomly into the following 4 groups according to the material treatments: group 1, APF gel; group 2, fluoride varnish; and groups 3 and 4, fluoride tape supplemented with 5% NaF in either a methyl cellulose or poly vinyl acetate carrier, respectively. All specimens were submitted to alternate cycles of acid exposure in a cola beverage (pH 4.3) and artificial saliva for $6\;{\times}\;5\;min/day$ over a 5 day period. The micro-hardness was recorded each day and the lesion depth was measured after 5 days. The micro-hardness of the experimental sides of groups 2, 3 and 4 were significantly higher than that of their control sides and the experimental side of group 1 during the experimental period (p<0.05) except on the 5th day. The enamel surfaces of treatment groups 2, 3 and 4 showed significantly higher resistance to mineral loss in terms of the erosion depth (p<0.05) than group 1 and their control sides. There was no statistically significant difference among group 2, 3 and 4, indicating that the fluoride varnish and tapes produce similar results. Fluoride adhesive tapes are effective in reducing the progression of erosion and can be recommended for young patients who are more susceptible to dental erosion.

• Nuclear Engineering and Technology
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• v.44 no.5
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• pp.523-534
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• 2012

The objective of this study was to experimentally investigate the effect of heat curing methods on the temperature history and strength development of slab concrete exposed to $-10^{\circ}C$. The goal was to determine proper heat curing methods for the protection of nuclear power plant structures against early-age frost damage under adverse (cold) conditions. Two types of methods were studied: heat insulation alone and in combination with a heating cable. For heat curing with heat insulation alone, either sawdust or a double layer bubble sheet (2-BS) was applied. For curing with a combination of heat insulation and a heating cable, an embedded heating cable was used with either a sawdust cover, a 2-BS cover, or a quadruple layer bubble sheet (4-BS) cover. Seven different slab specimens with dimensions of $1200{\times}600{\times}200$ mm and a design strength of 27 MPa were fabricated and cured at $-10^{\circ}C$ for 7 d. The application of sawdust and 2-BS allowed the concrete temperature to fall below $0^{\circ}C$ within 40 h after exposure to $-10^{\circ}C$, and then, the temperature dropped to $-10^{\circ}C$ and remained there for 7 d owing to insufficient thermal resistance. However, the combination of a heating cable plus sawdust or 2-BS maintained the concrete temperature around $5^{\circ}C$ for 7 d. Moreover, the combination of the heating cable and 4-BS maintained the concrete temperature around $10^{\circ}C$ for 7 d. This was due to the continuous heat supply from the heating cable and the prevention of heat loss by the 4-BS. For maturity development, which is an index of early-age frost damage, the application of heat insulation materials alone did not allow the concrete to meet the minimum maturity required to protect against early-age frost damage after 7 d, owing to poor thermal resistance. However, the combination of the heating cable and the heat insulating materials allowed the concrete to attain the minimum maturity level after just 3 d. In the case of strength development, the heat insulation materials alone were insufficient to achieve the minimum 7-d strength required to prevent early-age frost damage. However, the combination of a heating cable and heat insulating materials met both the minimum 7-d strength and the 28-d design strength owing to the heat supply and thermal resistance. Therefore, it is believed that by combining a heating cable and 4-BS, concrete exposed to $-10^{\circ}C$ can be effectively protected from early-age frost damage and can attain the required 28-d compressive strength.

• YAKHAK HOEJI
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• v.57 no.2
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• pp.77-86
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• 2013

The neuroprotective effects of herbal ethanol extract (GP-EX) from Gynostemma pentaphyllum on dopamine neurons in animal model of Parkinson's disease (PD) were investigated. Rats and mice were administered with rotenone (2.5 mg/kg) for 28 days and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg) for 5 days for the PD models, respectively and the animals were simultaneously treated with GP-EX (30 mg/kg, daily). After preparing the PD models, the animals were also administered with L-DOPA (10 mg/kg) for 14 days with or without GP-EX treatment. Treatment with GP-EX (30 mg/kg) inhibited the rotenone- and MPTP-induced neurotoxic effects in dopamine neurons of rats or mice, which was determined by the numbers of tyrosine hydroxylase-immunohistochemical staining survival cells, as well as the levels of dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid. GP-EX (30 mg/kg) also showed the protective effects on neurotoxicity which was induced by long-term administration of L-DOPA (10 mg/kg) in rotenone- and MPTP-induced animal model of PD. The used doses of GP-EX (30 mg/kg) did not produce any signs of toxicity, such as weight loss, diarrhea, or vomiting, in rats and mice during the treatment periods. These results suggest that GP-EX has the protective functions against chronic L-DOPA-induced neurotoxic reactions in dopamine neurons of rotenone- and MPTP-induced animal model of PD. Therefore, the natural GP-EX may be beneficial in the prevention of PD progress and L-DOPA-induced neurotoxicity in PD patients.