• 천문학회보
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• 제38권2호
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• pp.70.2-70.2
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• 2013

We present collections of optical photometry for a pre-main sequence star HBC 722. It showed large amplitude optical outburst (${\Delta}V=4.7$ mag) in 2010 and classified as a FU Orionis type object. We have been observing HBC 722 from 2011 April to 2013 May, using Camera for QUasars in EArly uNiverse (CQUEAN) attached to the 2.1 m Otto Struve telescope at the McDonald Observatory. Time-series monitoring data (minute-scale interval) were obtained in SDSS r, i and z bands to see short-scale behaviors as well as trace the long-term brightness changes after the eruption in 2010. Interestingly, it started to brighten from 2011 early summer and became brighter than the first outburst peak in our 2013 May observation. We expect that the recovering phase would result from re-increase of disk accretion rate, might attribute to distinctive short-scale color features. In this presentation, we report long- and short-timescale optical behaviors of HBC 722 in the post-outburst phase.

• 한국대기환경학회지
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• 제30권2호
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• pp.139-149
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• 2014

A new technique, namely the combination of satellite and trajectory analysis (CSTA), for exploring the spatio-temporal distribution information of volcanic ash plume (VAP) from volcanic eruption. CSTA uses the satellite derived ash property data and a matching forward-trajectories, which can generate airmass history pattern for specific VAP. In detail, VAP properties such as ash mask, aerosol optical thickness at 11 ${\mu}m$ ($AOT_{11}$), ash layer height, and effective radius from the Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite were retrieved, and used to estimate the possibility of the ash forecasting in local atmosphere near volcano. The use of CSTA for Iceland's Eyjafjallaj$\ddot{o}$kull volcano erupted in May 2010 reveals remarkable spatial coherence for some VAP source-transport pattern. The CSTA forecasted points of VAP are consistent with the area of MODIS retrieved VAP. The success rate of the 24 hour VAP forecast result was about 77.8% in this study. Finally, the use of CSTA could provide promising results for VAP monitoring and forecasting by satellite observation data and verification with long term measurement dataset.

• 대한소아치과학회지
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• 제44권1호
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• pp.11-19
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• 2017

본 연구는 유치 융합치의 특징과 영구치열에 미치는 영향을 알아보고자 하였다. 4 - 6세 어린이 중 융합치가 관찰되는 84명의 어린이를 조사하였으며, 융합치의 분포는 상악보다 하악에서, 2개의 융합치보다 1개가 발생한 경우가 높은 비율로 관찰되었으며 우식이환율은 하악보다 상악에서 높았다. 계승 영구치의 선천적 결손은 상악 유중절치와 유측절치 융합, 하악 유측절치와 유견치 융합, 하악 유중절치와 유측절치 융합 순이었으며, 과잉치 발생은 상악 유중절치와 유측절치 융합, 하악 유중절치와 유측절치 융합, 하악 유측절치와 유견치 융합 순으로 나타났다. 유치의 융합에 의한 계승 영구치의 맹출 지연은 하악에서는 나타나지 않았으나 상악의 경우 지연 발육되는 과잉치의 발생 가능성 및 이로 인한 영구 중절치의 맹출 지연 양상이 높은 빈도로 관찰되었다. 따라서 융합치로 인한 맹출 지연의 문제를 최소화하기 위해 주기적인 방사선 검사 및 조기 치료가 필요할 것으로 사료된다.

• Journal of Preventive Medicine and Public Health
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• 제40권2호
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• pp.155-161
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• 2007

Objectives : Bisphenol A diglycidyl ether (BADGE) is the major component in commercial liquid epoxy resins, which are manufactured by co-reacting bisphenol A with epichlorohydrin. This study was performed to show the developmental effects of prenatal and postnatal exposures to BADGE in male rat offspring. Methods : Mated female rats were divided into four groups, each containing 12 rats. The dosing solutions were prepared by thoroughly mixing BADGE in corn oil at the 0, 375, 1500 and 3000 mg/kg/day concentrations. Mated females were dosed once daily by oral gavage on gestation day (GD) 6 - 20 and postnatal day (PND) 0 - 21. Pregnant female dams were observed general symptoms and body weight. Also, male pups were observed the general symptoms, body weight, developmental parameters (e.g. anogenital distance, pina detachment, incisor eruption, nipple retention, eye opening, testis descent), organ pathologic changes and hormone levels of plasma. Results : Pregnant rats treated with BADGE died at a rate of about 70% in the 1500 mg/kg/day group and all rats treated with 3000 mg/kg/day died. Body weight, for male pups treated with doses of 375 mg/kg/day, was significantly lower than in the control group at PND 42, 56, and 63 (p<0.05). Evaluation of body characteristics including; separation of auricle, eruption of incisor, separation of eyelid, nipple retention, descent of testis, and separation of the prepuce in the BADGE treated group showed no difference in comparisons with the control group. AGD and adjusted AGD (mm/kg) for general developmental items in BADGE 375 mg/kg/day treated pups tended to be longer than in controls, however, these differences were not statistically significant. Relative weights of adrenal gland, lung (p<0.05), brain, epididymis, prostate, and testis (p<0.01) were heavier than in control in measures at PND 9 weeks. There were no significant changes in comparisons of histological findings of these organs. Loss of spermatids was observed in the seminiferous tubule at PND 9 weeks, but no weight changes were observed. The plasma estrogen levels were similar in the control and treatment groups at PND 3, 6 and 9 weeks. The plasma testosterone levels in the control group tended to increase with age. However, in the BADGE 375 mg/kg/day treated male pups it did not tend to increase. Conclusions : These findings suggest that BADGE is a chemical that has developmental effects consistent with it being an endocrine disruptor.

• 대한소아치과학회지
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• 제23권2호
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• pp.389-400
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• 1996

In Class II amalgam restoration in deciduous molar, failure rate and incidence of recurrent caries are high as children become older. In order to preserve deciduous molars till the physiologic exfoliation time, stainless steel crown is a choice of the treatment. As a result of a careless treatment, such as overhanging margin, poor marginal adaptation, poor proximal contour and inadequate mesiodistal width give rise to interfering eruption of the adjacent teeth, recurrent caries and chronic gingival irritation and insufficient arch length respectively. In this study, 252 s.s. crowned teeth extracted due to physiologic exfoliation or periapical lesion. The purpose of this study is to analyze the marginal adaptation of stainless steel crown to the deciduous molar in order to obtain better clinical result. The results were as follows : 1. Between the length of s.s. crown and the marginal gap of crown, positive correlations were shown. 2. Largest amount of marginal gap was shown at buccal side in upper deciduous molars and lower first deciduous molar, lingual side in lower second deciduous molar. But no significant diffrence were found statistically compared to second most largest one. 3. Incidence of exposed restoration and recurrent caries were higher in proximal surface than buccal/lingual surface. And extension of restoration below the margin of s.s. crown gives rise to higher rate of recurrent caries. 4. Defect of contour was found in 34%, frequently found in lower 1st deciduous molar and upper 1st deciduous molar. 5. Marginal polishing defects were found in 23%. 6. Ledge was formed in 10% especially in lower 1st deciduous molar and lower 2nd deciduous molar. 7. 16% of the teeth had wear facet due to traumatic occlusion, 7% of them had occlusal perforation.

• 한국치위생학회지
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• 제4권1호
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• pp.31-48
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• 2004

Dental caries taking place with milk teeth affects eruption of permanent teeth adversely, and thus, it is very important to prevent dental caries from taking place with a child in maintaining his/her physical, mental and emotional health. In this study as conducted to obtain basic data to be required for development of a program for letting preschool children form a habitual life for oral health and right dietary life, a total 172 children aged 5 years and 6 years were selected from children who lived in Hwasung-si, Kyunggi-do and attended preschools (childrens houses) located there with the consent of their guardians. Then, the weight length index (WLI) and blood components of each child were analyzed, and each relation between the weight length index (WLI) and dental caries of milk teeth and between blood components and dental caries of milk teeth was comparatively examined, and thereby, the following results were obtained. When the dmf rate of each group according to the obesity was examined, it was found to be 87.50% in the under-weight group, 71.20% in the normal weight group and 83.87% in the overweight group. And when the dmft rate of each group was examined, it was found to be 48.43% in the under-weight group, 37.10% in the normal weight group and 47.17% in the overweight group. Also, when the dmft index of each group was examined, it was found to be 3.9 in the under-weight group, 3.0 in the normal weight group and 3.8 in the overweight group. That is to say, the under-weight group and the overweight group having an abnormal weight were found to be higher in all of the dmf rate, the dmft rate and the dmft index than the normal weight group. It could be, therefore, known that normal weight should be maintained in order to prevent dental caries of milk teeth. And, it is thought that a right dietary life habit ensuring intake of balanced nutrients should be formed for maintenance of a normal weight. As a result of examining the relation between nutrient components in blood and dental caries of milk teeth, in the case of children with no dental caries, inorganic nutrient components of blood had a tendency to be a little higher, but no statistical significance was observed therein. Meanwhile, it was found that there was a relation between blood type and the dmft index.

• 대한소아치과학회지
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• 제34권2호
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• pp.264-272
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• 2007

연구 목적은 영유아의 구강위생관리방법을 개선하기 위한 것으로서, 시중의 영유아용 구강위생관리용품을 조사하여 분류하고 안전성에 대한 문헌고찰을 실시하였으며, 익산시내 영유아 보육자들 672명에게 구강위생관리용품의 사용경험을 포함한 구강위생관리방법에 대하여 조사하였다. 영유아용 구강위생관리용품은 구강 티슈, 손가락 칫솔, 성장단계별 칫솔, 전동칫솔, 어린이용 칫솔, 삼켜도 되는 영유아용 치약을 포함한 성장단계별 치약, 어린이용 불소치약 등이 있었다. 사용 경험은 구강티슈가 62.5%, 손가락 칫솔이 70.9%, 3단계 칫솔이 55.9%, 삼켜도 되는 영유아용 치약이 87.4%이었다. 이를 닦아주기 시작한 때는 이가 날 때부터와 생후 1년경이 79.0%, 생후 2년경과 3년경이 21.0%이었고, 이닦기 중 치약을 삼키는 비율은 48개월 미만에서 22%이었고 $48{\sim}59$개월에서는 9%, 60개월 아상에서는 3%로 감소하였다. 보육자가 어린이 이를 닦아주는 비율은 48개월 미만에서 52%, $48{\sim}59$개월에서는 42%이었고 60개월 이상에서는 26%이었다. 영유아기 구강위생관리의 기본 방법은 이닦기를 통해 치아표면의 치태를 제거하는 것이며, 이닦기의 주된 방법은 칫솔질이고 치약을 보조적으로 사용할 수 있다. 구강위생용품 사용시에는 질식, 삼킴, 목구멍 손상 등에 주의해야 한다. 일반적으로 3세 이전에는 불소치약의 사용이 권장되지 않으며, 사용시에는 최소량을 사용하고, 삼키지 않고 뱉도록 보호자가 지도 감독하여야한다.

• 천문학회보
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• 제40권1호
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• pp.61.1-61.1
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• 2015

We performed a monitoring campaign of a Jupiter-Family comet 17P/Holmes, which underwent the dramatic outburst on 23.3 October 2007 at $r_h=2.44AU$, to investigate the secular change in activity and subsequent physical properties of the inner dust coma before and after the 2014 perihelion passage. The monitoring observation was carried out over two years: from May to July 2013, from July to November 2014, and January 2015 with ~weekly cadence. We conducted photometry monitoring in Rc band using four ground-based telescopes, which are the Ishigakijima Astronomical Observatory 105cm telescope, the Okayama Astrophysical Observatory 50cm telescope, the Nishi-Harima Astronomical Observatory 2m telescope, and the T30 51cm i-telescope, respectively. In order to examine the dust production rate, we put a constraint upon the physical distance from the center of the nucleus as rho=2500km and conducted aperture photometry. We found that the average absolute Rc magnitude over the period between July to November 2014 was mR(1,1,0)~12.29, which was approximately 1.5 magnitudes fainter than those of 2013 data. Accordingly, comet 17P/Holmes seemed to become dormant, although a minor eruption was detected on January 26, 2015. In this presentation, we will introduce our ongoing project for 17P/Holmes and discuss why the nucleus becomes dormant within one orbital period.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.45.1-45.7
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• 2016

Background: We evaluated and compared the outcomes of different ossification processes in patients with alveolar cleft in whom correction was performed using endochondral bone graft or intramembranous bone graft. Methods: The patients were divided into two groups: the endochondral bone (iliac bone or rib bone) graft group and the intramembranous bone (mandibular bone) graft group. Medical records and radiologic images of patients who underwent alveolar bone grafting due to alveolar cleft were analyzed retrospectively. Through postoperative and follow-up radiologic images, the height of the interdental bone septum was classified into four types based on the highest point of alveolar ridge. Then, the height of the interdental bone septum and the area of the bone graft were evaluated according to the type of bone graft. In addition, the occurrence of complications and the need for an additional bone graft, the result of postoperative orthodontic treatment, and the eruption of impacted teeth were investigated. Results: Thirty patients were included in this study. There was no significant difference in the change of the interdental bone height and the area of the bone graft according to the type of bone. There was no significant difference in the success rate of the surgery according to the type of bone. One patient underwent an additional bone graft surgery during the follow-up period. Conclusions: The outcomes of alveolar bone grafting were not significantly different according to the type of bone graft. If appropriate to the size of the recipient site, the chin bone is a useful graft material in alveolar cleft, as is the iliac bone.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권1호
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• pp.49-57
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• 2006

Mandibular fractures have higher incidence rate compared to facial bone fractures because of relatively prominent form. Specially, mandibular angle fractures were known as common fracture site because of morphological anatomic structure. The mandibular third molar appears to be the most frequent impacted tooth. The mandibular third molar have influence on mandibular angle fractures according to it's eruption state. Also, the mandibular angle fracture including the third molar may influence on post operative infection whether the third molar is in impacted or extracted state when reduction of fracture site is operated. The presence or absence and degree of impaction of the mandibular third molar were assessed for each patient and were related to the occurrence of the mandibular angle fracture. The extraction or non extraction of the mandibular third molar were related to the occurrence of the post operative infection in the reduction of mandibular angle fractures. In the presence of mandibular third molar, the possibility of mandibular angle fractures were relatively common. When viewing the mandibular third molar at occlusal plane, the possibility of mandibular angle fractures were high in the class C group. The possibility of mandibular angle fractures were high in the mesial angulation and partial impaction. There was a statistically significant difference(P<0.05). In complete erupted mandibular third molar, the possibility of post operative infection occurs quite often, but there was no statistical significant difference(P>0.05). In the extracted or non extracted of mandibular third molar, the post operative infection showed no statistical significant difference(P>0.05). With the results mentioned above, mandibular third molar was significantly more susceptible to mandibular angle fracture. In the reduction of mandibular angle fracture, it was recommended that mandibular third molar should be extracted especially in case of pericoronitis, periodontitis and other infections.