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정정권,윤규호,전인성,김기엽,김현우,권순욱 大韓顎顔面成形再建外科學會 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.5
The ranula is a form of mucocele which specifically occurs in the floor of the mouth. The ranula is classfied into simple ranula and plunging ranula according to the mechanism of development such as the salivary duct obstruction or the extravasation. Clinically this lesion develops as a slowly enlarging painless, fluctuant mass on one side of the floor of the mouth and the mucosa may have a translucent bluish color. An 8-month-old male infant visited our hospital with the chief complaint of the left submandibular swelling and the mass on the floor of the mouth. We tentatively diagnosed a simple ranula. The marsupialization was performed but the sign and the symptom did not subside, so we took the MRI. By the MRI we diagnosed a plunging ranula and excised the sublingual gland via the intraoral approach. The correct diagnosis is essential for the most effective treatment, which is the excision of the sublingual gland.
섬유모세포의 종류에 따른 불멸화된 구강 각화세포의 삼차원적 배양에 관한 연구
정정권(Jeong-Kwon Cheong),윤규호(Kyu-Ho Yoon),김은철(Eun-Cheol Kim) 대한구강악안면외과학회 2007 대한구강악안면외과학회지 Vol.33 No.3
Objective: In organotypic culture of immortalized human oral keratinocytes (IHOK), the change of the growth and differentiation was investigated according to the fibroblast type and the involvement of mitogen-activated protein (MAP) kinase. Materials & Methods: IHOK was cultured three dimensionally with gingival fibroblast (GF), dermal fibroblast (DF) and immortalized gingival fibroblast (IGF). We characterized biologic properties of three dimensionally reconstructed IHOK by histological, immunohistochemical, and Western blot analysis. We also investigated whether MAP kinase pathway was involved in epithelial-mesenchymal interaction by Western blot analysis. Results: The best condition of three dimensionally cultured IHOK was the dermal equivalent consisting of type I collagen and IGF. IGF increased the expression of more proliferating cell nuclear antigen (PCNA), involucrin than GF and DF in response to co-culture with IHOK. Extracellularly regulated kinase (ERK) pathway was activated in organotypic co-culture with IGF. Conclusion: The organotypic co-culture of IHOK with dermal equivalent consisting of type I collagen and IGF resulted in excellent morphologic and immunohistochemical characteristics and involved ERK pathway. The epithelial-mesenchymal interaction was activated according to the fibroblast type.
정정권(Jeong-Kwon Cheong) 대한구강악안면외과학회 2006 대한구강악안면외과학회지 Vol.32 No.2
Objectives: Pericoronitis was the most common indication for mandibular third molar surgery and there are no universally acceptable predictive criteria for pericoronitis occurrence. This study was designed to analyze the correlation of the pericoronitis and the eruption state of the mandibular third molar using panoramic radiographs statistically. Materials and Methods: 218 patients whose chief complaint was the extraction of the mandibular third molar were examined. The presence and absence of pericoronitis, age, sex, position of extraction site, angulation, impaction degree, position to the anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar were assessed. Then the correlation of pericoronitis and the eruption state of the mandibular third molar were analyzed by Student’s t-test and chi-square test. Results: There was no correlation between Pericoronitis and age, sex, position of the mandibular third molar. The angulation(P=0.005), impaction degree(P=0.043), relation with anterior border of mandibular ramus(P=0.003), distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar(P〈0.05) were correlated with pericoronitis. Conclusions: The occurrence of the pericoronitis can be predicted by the eruption state of the mandibular third molar such as angulation, impaction degree, relation with anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of third molar.
Kwon, Cheong Hoon,Chun, Kyoung-Yong,Kim, Shi Hyeong,Lee, Jae-Hyeok,Kim, Jae-Ho,Lima, M?rcio D,Baughman, Ray H,Kim, Seon Jeong RSC Pub 2015 Nanoscale Vol.7 No.6
<P>Torsional behaviors of polymer-infiltrated carbon nanotube (CNT) yarn muscles have been investigated in relation to molecular architecture by using atomic force microscopy (AFM). Two polymers with different stiffnesses, polystyrene (PS) and poly(styrene-b-isoprene-b-styrene) (SIS), were uniformly infiltrated into CNT yarns for electrothermal torsional actuation. The torsional behaviors of hybrid yarn muscles are completely explained by the volume change of each polymer, based on the height and full width at half maximum profiles from the AFM morphological images. The volume expansion of the PS yarn muscle (1.7 nm of vertical change and 22 nm of horizontal change) is much larger than that of the SIS yarn muscle (0.3 nm and 11 nm change in vertical and horizontal directions) at 80 C, normalized by their values at 25 C. We demonstrate that their maximum rotations are consequently 29.7 deg mm(-1) for the PS-infiltrated CNT yarn muscle (relatively larger rotation) and 14.4 deg mm(-1) for the SIS-infiltrated CNT yarn muscle (smaller rotation) at 0.75 V m(-1). These hybrid yarn muscles could be applied in resonant controllers or damping magnetoelectric sensors.</P>
Low-Frequency Noise in Amorphous Indium–Gallium–Zinc-Oxide Thin-Film Transistors
Jeong-Min Lee,Woo-Seok Cheong,Chi-Sun Hwang,In-Tak Cho,Hyuck-In Kwon,Jong-Ho Lee IEEE 2009 IEEE electron device letters Vol.30 No.5
<P>We have investigated the low-frequency noise (LFN) properties of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) as a function of frequency, bias, and channel length of devices. The measured noise power spectral density of drain current (<I>S</I> <SUB>iD</SUB>) shows that the low-frequency noise in a-IGZO TFTs obeys the classical 1/<I>f</I> noise theory, i.e., it fits well to a 1/<I>f</I> <SUP>gamma</SUP> power law with gamma ~ 1 in the frequency range of 10 Hz to 1 kHz. From the dependence of normalized noise power spectral density (<I>S</I> <SUB>iD</SUB>/<I>ID</I> <SUP>2</SUP>) on the gate voltage, mobility fluctuation is considered as a dominant LFN mechanism in a-IGZO TFTs. The magnitude of <I>S</I> <SUB>iD</SUB>/<I>ID</I> <SUP>2</SUP> is inversely proportional to the channel length of devices, which indicates that contact noise is insignificant in a-IGZO TFTs.</P>
정해관,권용욱,어경윤,김병준,양정선,정철,진영우,이미영,강성규 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.3
Authors report a first Korean case of polyneuropathy in an acrylamide producing factory together with an environmental and epidemiologic survey for the ten workers of the same workplace and 46 workers in the production and manufacturing acrylamide in Ulsan, Korea. The case is 30 years old man who worked in the production of the acrylamide for two years. In August, 1997, he had a weakness of the lower extremity with loss of body weight of 15 Kg which progressed to paresthesia of the limbs, the loss of vibration sense, difficulty in walking, speech disturbance, dysuria, constipation, difficulty in erection and swallowing difficulty. Neurologic examination showed a complete loss of vibration and position sense, and loss of deep tendon reflex in all the limbs. There was a contact dermatitis-like skin lesion on the feet. Electrodiagnostic test showed a generalized polyneuropathy of moderate degree involving motor and sensory component of peripheral and cranial nerves. After 8 months' cessation from exposure and supportive care, his symptoms were completely resolved, but abnormality in electrodiagnostic test and vibrotactile perception threshold still persisted, although much improved than before. There were 11 workers in the same workplace of the case, producing acrylamide by microorganism as a catalyst. Environmental monitoring of the workplace revealed air borne concentration of the acrylamide to be from 0.05 to 0.23 mg/m3 by personal sampling and from 7.65 to 11.65 mg/m3 by area sampling during filter exchanging process, which far exceeds TLV-TWA of 0.03 mg/m3. However, acrylamide was not detected from the plasma of the workers. Symptom questionnaire showed a markedly higher complain of neurologic symptoms, compared to the workers of the other acrylamide producing companies. Electrodiagnostic test showed a several workers are in the lower normal range without definite abnormality. Vibrotactile perception threshold by Vibratron Ⅱ showed a significantly increased threshold in the workers of the same workplace compared to the other acrylamide workers and significantly decreased test score of color vision compared to normal controls. After improvement of the production process and strict wearing of the protective device, most workers reported the improvement of clinical symptoms, but vibrotactile perception threshold was not improved. These result suggests the need for the effective environmental monitoring together with a periodic biological monitoring. Development of effective screening test is urgently needed to control and assess the skin absorption of acrylamide.