• The Korean Journal of Community Living Science
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• v.14 no.3
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• pp.13-19
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• 2003

The purpose of this study was to investigate the UVA radiation protection effects of summer hats currently on the market with the purpose of making it possible to choose a hat with suitable UVA protection. Twelve different summer hats from the market were selected for the experiment. The results are summarized as follows: It is more effective to wear a hat than not wear a hat to block UVA radiation. Summer hats with the greatest degree of protection, from highest to lowest, are cotton, straw2, and straw1. In the area of the forehead, which is rarely influenced by the irradiation angle, the cotton hat was the most effective in protecting from UVA radiation because the material density was greater than that of the straw hats. A hat with a 8.5 cm brim was more effective at blocking UVA radiation on the jaw than 6 cm, 4 cm, and 0 cm wide brims, but it still couldn't block the radiation completely. Irradiation amounts at 11:00 AM on the forehead, jaw! s and left and right cheeks were lower than amounts measured on the back of the neck. This revealed that irradiation amounts depend on the shape of the hat and time of day. A hat with a brim encircling the head was found to be more effective in blocking UVA radiation than a hat with only a front or side brim.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.396-405
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• 2017

We observed the osteological development in larvae and juveniles of Korean spotted sleeper Odontobutis interrupta bred in the laboratory in April 2014. Immediately after hatching, the prelarvae, which were about 4.27 mm long, showed ossification of the premaxillary bones in the upper jaw and the dentary and articular bones in the lower jaw. At 7.11 mm, the larvae showed complete fusion of the post-cleithra and ossification of the scapulae with the appearance of one hole. At 8.65 mm, the larvae showed ossification of seven ribs from the third abdominal vertebra and an increase in the length of the neural spine and hemal spine. The number of caudal fin rays increased to 19. At 11.9 mm, the juveniles showed ossification of three procurrent rays on the side of the parhypural bone as well as ossification of two procurrent rays on the side of the epural bone, indicating the complete ossification of all spicules.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.6
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• pp.332-337
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• 2015

Dental infections and maxillary sinusitis are the main causes of osteomyelitis. Osteomyelitis can occur in all age groups, and is more frequently found in the lower jaw than in the upper jaw. Systemic conditions that can alter the patient's resistance to infection including diabetes mellitus, anemia, and autoimmune disorders are predisposing factors for osteomyelitis. We report a case of uncommon broad maxillary osteonecrosis precipitated by uncontrolled type 2 diabetes mellitus and chronic maxillary sinusitis in a female patient in her seventies with no history of bisphosphonate or radiation treatment.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.51-58
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• 2010

English vowels play an important role in the daily communication between Korean students and international visitors. However, many Korean students still have difficulty producing them distinctively. Vowels vary according to shapes of oral and pharyngeal cavities, which are mainly determined by the degree of jaw opening and tongue position. Yang (2008a) proposed a simplified chart of English and Korean vowels for an educational purpose. He also suggested to use wooden chopsticks to secure distinguishable jaw openings. The purpose of this study is to tap whether wooden chopsticks can be applicable to a method for correcting English vowel pronunciation. Twelve male and female students participated in the recordings of eight /hVd/ words followed by additional recordings with wooden chopsticks between upper and lower teeth. The first and second formant trajectories of both natural and controlled vowel productions were obtained and compared at six equidistant measurement points using Praat. Results showed that the formant values of natural vowel productions were comparable to those of controlled productions. Vowels with similar formant trajectories of male students were separated with the aid of chopsticks. The width of each chopstick could be controlled similarly in the experiment. The author concludes that wooden chopsticks can be useful to correct vowel pronunciation. Further studies are desirable for native speakers to make perceptual evaluations of controlled vowel productions by nonnative speakers.

• Phonetics and Speech Sciences
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• v.12 no.2
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• pp.17-27
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• 2020

This paper examines kinematic characteristics of /pk/ clusters, as compared to /kk/ and /pp/ with varying vowel contexts and speech rate. The results of EMMA data from eight Seoul-Korean speakers indicate as follows. Firstly, comparing /pk/ to /pp/ sequences, lips closing movement was faster and spatially greater in the /a/-to-/a/ context while temporally longer in the /i/-to-/i/ context. It was smaller in spatial displacement and shorter in temporal duration in /pk/ sequences. Peak velocity did not vary. Secondly, comparing /pk/ with /pp/ and /kk/ controls, lip aperture was less constricted in the /a/-to-/a/ context than /i/-to-/i/, but the maximum contact between the upper and lower lips was invariant across different vocalic contexts within /pk/ sequences (/apka/=/ipki/). Categorical reduction of C1 in /pk/ sequences fell in with the low-vowel and fast-rate conditions with across-/within-speaker variability. Gradient reduction of C1 was observed in all C1C2 types, being more frequent in fast rate. Lastly, the jaw articulator was a stable indicator of rate effects. The implication of the current study is that gestural reduction occurs with categorical reduction and general spatiotemporal weakening in the assimilating contexts, while quantitative properties of gestures may be a reason for gradient reduction, not necessarily confined to place assimilation.

• The Journal of the Korean dental association
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• v.12 no.1
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• pp.29-34
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• 1974

In order to appreciate the school dental services of the primary, middle, and high school and to get the basic data for the university dental service programs in Korea, the author had examined the oral health status of 1,300 freshmen in S University. Then, the followed results were obtained from the calculation and evaluation of DEMT index, DT index, MT index, FT index, DT rate, MT rate, FT rate, debris deposit rate, calculus deposit rate, periodontal disease rate, and abnormal jaw relation rate. 1. DMFT index in the freshmen was higher than that of the Korean youth in the same age. 2. It seems the above result to be appeared from the influence of the intake of the more carbohydrate foods in the freshmen. 3. In the freshmen, MT rate was lower, and FT rate higher than in the Korean youth in the same age. 4. The oral hygiene condition was good in 3.15% of the freshmen. 5. Calculus was not deposited in 8.69% of the freshmen. 6. In 9.69% of the freshmen, the periodontium was healthy. 7. In Korea, the school dental services in the primary, middle, and high schools must be improved. 8. There was the abnormal jaw relation in 12.92% of the freashmen.

• Korean Journal of Head & Neck Oncology
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• v.39 no.2
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• pp.35-39
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• 2023

Solitary fibrous tumor (SFT), which was initially believed to be a subtype of mesothelioma, has been reported to occur outside the pleura. In the head and neck region, it primarily manifests in the oral or nasal cavity, with rare occurrences in the facial region. A 40-year-old woman visited our hospital with a mass on her chin. Prior to surgery, involuntary movement was observed in the ipsilateral corner of the mouth upon palpation of the mass. Special care was taken during the surgical procedure to avoid damaging the facial nerve. The mass was excised, and histological examination and immunohistochemical analysis confirmed the diagnosis of an SFT. Here, we present the first reported case of an SFT diagnosed in a jaw mass in Korea. The objective of this study was to highlight the importance of the diagnostic accuracy of SFTs in lower jaw masses.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.13.1-13.12
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• 2016

Background: Mandibular motion tracking system (ManMoS) has been developed for orthognathic surgery. This article aimed to introduce the ManMoS and to examine the accuracy of this system. Methods: Skeletal and dental models are reconstructed in a virtual space from the DICOM data of three-dimensional computed tomography (3D-CT) recording and the STL data of 3D scanning, respectively. The ManMoS uniquely integrates the virtual dento-skeletal model with the real motion of the dental cast mounted on the simulator, using the reference splint. Positional change of the dental cast is tracked by using the 3D motion tracking equipment and reflects on the jaw position of the virtual model in real time, generating the mixed-reality surgical simulation. ManMoS was applied for two clinical cases having a facial asymmetry. In order to assess the accuracy of the ManMoS, the positional change of the lower dental arch was compared between the virtual and real models. Results: With the measurement data of the real lower dental cast as a reference, measurement error for the whole simulation system was less than 0.32 mm. In ManMoS, the skeletal and dental asymmetries were adequately diagnosed in three dimensions. Jaw repositioning was simulated with priority given to the skeletal correction rather than the occlusal correction. In two cases, facial asymmetry was successfully improved while a normal occlusal relationship was reconstructed. Positional change measured in the virtual model did not differ significantly from that in the real model. Conclusions: It was suggested that the accuracy of the ManMoS was good enough for a clinical use. This surgical simulation system appears to meet clinical demands well and is an important facilitator of communication between orthodontists and surgeons.

• Progress in Medical Physics
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• v.6 no.2
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• pp.13-19
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• 1995

The behavior of the correction factor associated with the collimator opening(head-scatter factor) were investigated for the 6MV x-ray beams of medical linear accelerator. The primary photon fluence was measured in air quasi-small fied size. Consideration in this study was given to the effect of head scatter factor with quasi-small fied size, the upper and lower collimator jaw scatter collection factors of quasi-small field (4-10cm) were measured with ion chamber. In general, the wedge factors which are used clinical practics are ignored of dependency on field sizes and depth. In wedge factors for each wedge filter were measured at various depth by using 6MV X-ray. In this present we inverstigated systematically the depth and field sizes dependency to determine the absorbed dose more accurately. Head scatter(upper-lower collimator jaw)appears to be (1) a small effect, less than 5％ over the range of clinical field sizes (2) generated primarily at the flattening filter and therefored influenced most by the upper collimator setting.

• Animal Systematics, Evolution and Diversity
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• v.32 no.1
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• pp.28-37
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• 2016

We describe the morphological characteristics of two morids, Gadella jordani and Physiculus japonicus, belonging to the order Gadiformes, based on Korean specimens collected from the Korean ocean. Two specimens of Gadella jordani was first collected from Jeju Island, Korea and the East Sea, Korea, in 2013-2014. This species is characterized by 8, 67-69 dorsal fin rays, 66-71 anal fin rays, 5+13 gill rakers, no barbel on the lower jaw, no vomerine teeth, and a ventral luminous organ closer to the anus than to the interventral line. We described it as the first record to the Korean fish fauna, and proposed the new Korean name "Min-su-yeom-dae-gu-sok" for the genus Gadella, and "Min-su-yeom-dae-gu" for the species G. jordani. Physiculus japonicus was first reported by Koh and Moon in the year 1999 based on a single specimen in Korea. However, no study has been attempted to describe the morphological characteristics in Korea since then. In 2013-2014, three specimens of P. japonicus was collected from Jeju Island, Korea and the East Sea, Korea, and we redescribe P. japonicus in detail. This species is characterized by 9-10, 63-64 dorsal fin rays, 70-73 anal fin rays, 3+7-8 gill rakers, a short barbel on the lower jaw, and a ventral luminous organ equidistant between the interventral line and the anus.