• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.4
• /
• pp.261-265
• /
• 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
• /
• v.30 no.4
• /
• pp.399-403
• /
• 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
• /
• v.31 no.5
• /
• pp.440-443
• /
• 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
• /
• v.45 no.2
• /
• pp.195-201
• /
• 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.

• Journal of the Korea Safety Management & Science
• /
• v.22 no.2
• /
• pp.73-82
• /
• 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.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.8 no.3
• /
• pp.117-122
• /
• 2008

Generally, water is taken through channels and rivers, in which there are many weirs and structures, which cross rivers and temporally hold up water. But this way has its own shortcomings. It is main reason that the water flows through structures, and backwater come into being. So it causes many water quality problems and some flood side-effects and so on. In this study, among the various movable weirs, we installed bottom-discharged and air pressure movable weir in the experimental channel. And we analyzed flowing influence, which is followed by the angle variation of movable weir. We also make further study the flow characteristic variation followed by installing entrance at the bottom to discharge the bottom water. The analysis result was that installed weir angle was increased, and the discharge also gradually increased. The installed weir angle depended on the water quantity, which can be excluded in the bottom. In case of velocity, there was increased as maximum 21.9 times, according to there is entrance or not at the bottom. And in case of water level, it showed the water level of locally above the average decrease in the upper river of weir.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.15 no.3
• /
• pp.160-165
• /
• 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
• /
• v.37 no.1
• /
• pp.72-76
• /
• 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.

• Sleep Medicine and Psychophysiology
• /
• v.19 no.1
• /
• pp.35-41
• /
• 2012

Purpose: According to the statistics announced by the Ministry of Unification, the number of North Korean refugees living in South Korea has increased by 200 on average monthly in 2010. The number of refugees increased only by 300 annually until 2000. The total number of refugees as of February 2012 was 20,956. This study aims to investigate the psychobiology of the North Korean refugees who consulted psychiatric clinics among those living daily life in South Korea. Methods: The subjects of this study were 85 North Korean refugees that consulted psychiatric clinics from January 1, 2005 to July 2011. This study obtained demographic and psychiatric information in a retrospective approach. Results: Among the 85 North Korean refugees, 75 (88.2%) were females and their average age was 48 years of age. A total of 16 (18.8%) were admitted to a clinic and among the inpatients, 4 were admitted twice and two were admitted three times. As for the claimed symptoms of outpatients, insomnia was shown in 47 (55.3%) patients, headaches in 37 (43.5%), anxiety in 20 (23.5%), depression in 19 (22.4%), etc. The major symptoms represented by inpatients were insomnia in 14 (87.5%) patients, depression in 12 (75%), and headaches in 8 (50%), etc. Conclusion: The most frequent psychiatric symptoms of North Korean refugees living in South Korea were insomnia and headaches. It suggests that when performing psychiatric diagnosis and treatment of North Korean refugees, we have to take into consideration the fact that they claimed the physical symptoms more than the emotional ones. Also, from the aspect that most symptoms of North Korean refugees were insomnia, more profound research on sleep is required in the future.

• Journal of Environmental Health Sciences
• /
• v.46 no.4
• /
• pp.457-469
• /
• 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.