• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권4호
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• pp.261-265
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• 2009

Cystic hygroma, a cystic subtype of lymphangioma, is relatively rare tumor of lymphatic origin. The lesion is a benign, painless, soft, compressible malformation of the lymphatic system. They can arise anywhere along the lymphatic system, however they are usually located in the head and neck regions and in most cases appear by the age of 2 years. The cases in the adult is rarely occurred and a few cases are described in the literature. Surgical excision remains the treatment of choice. But complete extirpation of these lesion is often impossible, because the tumor tends to spread along vital structures. Therefore recurrence rates are accordingly high. This is a case report about 19 year old male patient with cystic hygro a on right retromandibular area. We obtained the successful, functional and esthetic result by surgical excision of the mass. Therefore, we report the case with a review of literatures.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권4호
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• pp.399-403
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• 2008

Benign fibrous histiocytoma(BFH) is a mesenchymal cell-originated tumor composed of cells with fibroblastic and histiocytic differentiation. BFH occurs predominantly on sun-exposed skin of extremities. Oral BFH lesions are uncommon. The majority of oral lesions includes the soft tissue but not the jaw bones. The lesion appears as well-defined multilocular radiolucencies associated with bony swelling when it occurs on the jaw. The lesion induces the thinning and expansion of the cortex and shows many thin, indistinct septa in the lesion. Surgical excision is the choice of treatment. The recurrence rate is low and metastasis has not been reported. We report the clinical, radiographic and microscopic findings of a BFH case occurred in the mandible with literature reviews.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권5호
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• pp.440-443
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• 2009

Cleidocranial dysplasia(CCD) is a rare syndrome usually caused by an autosomal dominant gene or no apparent genetic cause. The skull is large and short with marked bossing of the frontal bone. Closure on the fontanelles and sutures is delayed. The clavicle may be unilaterally or bilaterally aplastic. Oral manifestations include multiple impacted permanent teeth, prolonged retention of primary teeth and multiple supernumerary teeth. There are many difficulties in the early diagnosis of CCD because a majority of the craniofacial abnormalities becomes obvious only during adolescence. Late diagnosis produce occlusional & psychological problem. Therefore early detection and treatment of CCD can reduce the period and the extent of orthodontic and surgical interventions. We experienced CCD patient with multiple supernumerary teeth and will report it with the literature review.

• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.195-201
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• 2017

This study was conducted to evaluate the resistance of heat-treated wood using the catalyst to decay caused by fungi for sapwood and heartwood of two tree species, Korean red pine (Pinus densiflora) and Japanese larch (Larix kaempferi), respectively. Wood samples were immersed for 10 min in sulfuric acid (7.5%) and then heat-treated at $130^{\circ}C$ for 90 min. Fomitopsis palustris, a brown-rot fungus, was used to examine the decay resistance of Korean red pine and Japanese larch wood. Weight and density of wood from the all conditions increased after heat treatment using the catalyst. Weight loss after decay resistance test was also dropped with a heat treatment. The lowest weight loss indicated at heat-treated heartwood of Japanese larch. Heat treatment using the catalyst effectively increased the resistance of wood to decay caused by fungi.

• 대한안전경영과학회지
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• 제22권2호
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• pp.73-82
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• 2020

IEC 60079-10-1 edition 2.0, the global standard for hazardous area classification, was newly revised in 2015. There are many differences compared to the previous edition 1.0 version, first released in 2008, so it has caused confusion in the industry. In case of edition 1.0, the hazardous area extent can be derived through the mathematical formula, but in case of edition 2.0, there was the problem that the exact hazardous area extent was not known because of the mathematical formula of the plot for applying the hazardous area extent was not presented. In this study, we converted the plot introduced in edition 2.0 to CAD format and derived the plot as the mathematical equations. Through this, we suggest the hazardous area extent formula of three states (heavy gas, diffusive, jet). As the IEC committee did not provide the mathematical formula of the hazardous area extent according to the release characteristic, it is impossible to apply the exact hazardous area extent. In this study, a mathematical approach was derived for the plot introduced in edition 2.0, which can reduce the confusion of the applying hazardous area extent.

• 한국방재학회 논문집
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• 제8권3호
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• pp.117-122
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• 2008

사람들은 수로 또는 하천에서 취수를 목적으로 하천을 횡단하는 보와 같은 수중 구조물을 설치하여 물을 임시 저류시켜 사용하는 방법을 이용하고 있으나, 구조물에 의하여 하천의 흐름이 정체되어 수질사고 및 홍수 등의 부작용이 발생하기도 한다. 본 연구에서는 다양한 가동보 중 저층수 배출식 공압식 가동보를 실험수로에 설치하여 가동보 설치각도 변화에 따른 흐름 영향을 분석하였으며, 저층수 배출을 위해 설치해 놓은 저층수 유입구에 따라 변화하는 흐름특성을 분석하였다. 분석 결과 보 설치 각도에 따라 저층수 배출장치로만 물을 배제시킬 경우 설치각도의 증가에 따라 유량은 점차 증가하며, 저층수 유입구의 유무 따른 흐름특성 변화는 유속의 경우 최대 21.9배 증가한 것을 확인할 수 있으며, 수위변화에는 크게 영향을 미치지 않는 것으로 나타났으나, 보 상류 부분에서 국부적으로 평균 이상의 수위 감소를 나타내고 있다.

• 한국산업보건학회지
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• 제15권3호
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• pp.160-165
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• 2005

Schools have significant and serious indoor environmental health problem, of which indoor air quality (IAQ) in school building may affect the health of the students and indirectly affect learning performance. Schools are of special concern when regarding indoor exposure to air pollutants, because students are particularly sensitive to pollutants and spend a significant amount of time in that environment. Therefore researches for improvement of indoor air quality have been developed such as installation of air cleaning device, ventilation system, titanium dioxide(TiO2) coating and so on. However, it is difficult to evaluate the magnitude of improvement of indoor air quality in field study because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. In this study, evaluation of reduction of formaldehyde emission rate in school indoor environments by far-Infrared ray coating material was carried out using mass balance model in indoor environment. we proposed the evaluation method of magnitude of improvement in indoor air quality, considering outdoor level and ventilation. Since simple indoor concentration measurements could not properly evaluate the indoor air quality, outdoor level and ventilation should be considered when evaluate the indoor air quality.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권1호
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• pp.72-76
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• 2011

Polymorphous low-grade adenocarcinomas (PLGA) are distinctive salivary gland neoplasms with a propensity to arise from the minor salivary glands. The most frequent location of PLGA is the palate, even though other locations have been described. Previously used terms for PLGA include lobular carcinoma and terminal duct carcinoma. Although the frequency of the tumor is unknown, the recognition of PLGA as an individual tumor has increased with the establishment of specific histopathological criteria characterizing the PLGA. The first choice of treatment is a wide surgical excision including the subjacent bone if necessary. The prognosis is generally good and the recurrence rate ranges from 17% and 22%. Distant metastases is unusual (9%) but occur mainly in the regional lymph nodes. This is a case report of a 67 year old female patient with PLGA who was treated with a wide excision by layers (2 stage) of the lesion including the surrounding bone. We present this case with a review of the relevant literature.

• 수면정신생리
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• 제19권1호
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• pp.35-41
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• 2012

목 적 : 본 연구에서는 이미 정착하여 일상 생활을 하고 있는 북한이탈주민들 중 정신과 진료를 받은 환자들을 대상으로 정신생리를 고찰하고자 하였다. 방 법 : 본 연구는 2005년 1월 1일부터 2011년 7월까지 정신과를 내원한 북한이탈주민 환자 85명을 대상으로 후향적으로 인구학적 정보 및 정신과적 정보를 획득하였다. 결 과 : 85명의 북한이탈주민 중 75명(88.2%)이 여자였으며, 평균연령은 48세였다. 외래에서 주로 호소한 증상으로는 불면 47명(55.3%), 두통 37명(43.5%), 불안감 20명(23.5%), 우울감 19명(22.4%) 등이었으며, 입원시 주된 증상은 불면 14명(87.5%), 우울감 12명(75%), 두통 8명(50%) 등이었다. 결 론 : 국내에 입국해서 생활하고 있는 북한이탈주민들이 가장 많이 호소하는 정신과적 증상은 불면, 두통 등으로 나타났다. 향후 북한이탈주민들을 정신과적 평가 및 치료함에 있어서 정서적 호소보다 신체적 증상을 더 많이 호소하는 특징을 고려하여야 함을 시사한다. 또한 북한이탈주민들의 가장 많은 증상이 불면이었다는 점에서 향후 이들을 대상으로 수면에 대한 심도 있는 연구가 이루어야 할 것이다.

• 한국환경보건학회지
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• 제46권4호
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• pp.457-469
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• 2020

Objective: This study was designed to estimate the precise nationwide number of those who used humidifier disinfectants (HDs) and experienced specific health effects, including death, due to exposure to HDs in Korea between 1994 and 2011. Methods: A total of 5,000 households (15,472 people) were surveyed by stratifying the sample with a design that is equivalent to nationally approved household systematic sampling and face-to-face interviews from October 16, 2019 to December 30, 2019. Results: The proportion of use of humidifier disinfectants at home was 18.4% (2,844/15,472 people) and the proportion of those who experienced health effects among those who were exposed to HDs was 10.7% (303/2,844 people). Based on these factors, it was estimated that 8.94 million people (95% CI=8.25-9.63 million) were exposed to HDs and 0.95 million people (95% CI=0.87-1.02 million) experienced health effects, which means almost one in five and one in fifty Koreans respectively. The estimated number of deaths from HDs were 20,366 people (95% CI=18,801-21,931). Conclusion: The survey was large and analyzed a representative sample across the country, so this estimation of the nationwide population exposed and at risk to HDs is more accurate and reliable than previous studies. However, it is necessary to confirm whether results similar to those of this study can be reproduced through a survey using a cross-sectional survey at the national level. In particular, a survey focused on death cases is needed.