• 대한치과교정학회지
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• 제40권2호
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• pp.66-76
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• 2010

폐쇄성 수면무호흡(obstructive sleep apnea, OSA)은 수면 중에 반복적으로 상기도의 완전폐쇄나 부분폐쇄가 일어나는 질환으로서 흡기된 공기는 반드시 상기도라는 연조직 관(tube) 구조를 통과해야 하므로 상기도의 폐쇄경향은 관의 형태 및 관을 통과하는 공기의 유체역학적 특성에 따라서도 큰 영향을 받을 수 있다. 본 연구에서는 OSA 환자 3인의 치료 전 상기도 CT 이미지를 이용하여 개별화된 3차원 유한요소모델 A, B, C를 제작하고, 비공 당 170, 200, 230 ml/s의 흡기유량에 대하여 3차원 전산유체역학 해석을 시행하였다. 상기도의 유속, 음압 그리고 압력강하를 측정한 결과 관찰된 3개의 모델에서 모두 단면적이 가장 작은 부위에서 유속이 증가하였고, 음압이 크게 나타났다. 기도의 형태는 구개인두와 구인두 부위에서 좁아지는 형태를 가지며, 최소 단면적 영역과 하인두 단면적의 차이가 클수록 유속과 음압의 변화가 크게 나타났다. 비강 부위의 최고 압력과 최소 단면적 영역의 최저 압력의 차이를 의미하는 압력강하는 상기도 저항을 종합적으로 판단할 수 있는 유용한 지표이며, 유량에 따라 증가하였다.

• Advances in pediatric surgery
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• 제2권2호
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• pp.119-128
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• 1996

The survey on branchial anomalies was conducted by Korean Association of Pediatric Surgeons. A total of 173 cases were reported, which were managed by 36 members and cooperators during the three years from January 1, 1993 through December 31, 1995. The following results were obtained by retrospective analysis of the 173 cases of branchial anomalies. The presenting symptoms were cervical mass in 101 cases, pit with or without discharge in 71, cervical abscess in 47 and respiratory difficulty in 3. The average age of the patients with cervical abscess was 52 months. Seventy(79%) of 89 patients with branchial anomalies and a cystic mass had their first clinical manifestations by 1 year of age, while 40(51%) of 78 patients with only a branchial cyst had their first clinical manifestation in first year of life. Radiologic studies were carried out in 77 patients (43%). The preferred diagnostic modalities were ultrasonography(47 patients), simple neck radiogram(19) and CT scan(17). Preoperative diagnosis was correctly made in 156(91%) of 173 patients. Seventeen patients were incorrectly diagnosed as thyroglossal duct cyst in 5 patients, cystic hygroma in 4, dermoid cyst in 3, and lymphadenopathy in 3. There were no remarkable difference in sex and laterality of presentation but bilateral lesions were found in 9(5%) patients and unusual locations of the anomalies were the manubrium, left subclavicular area, median cervial area, preauricular and parotid area. There were 78(45%) patients with cyst, 52(30%) patients with sinus, 35(20%) patients with fistula and 8(5%) patient with skin tag. Embryological classification was possible in only 64(37%) patients. The 2nd branchial anomaly was present in 50(78%), the 1st branchial anomaly in 10(18%), and the 3rd or 4th branchial anomaly in 4(6%). Histopathological study of the lining epithelium(N=134) is recorded that 45% were lined with squamous epithelium, 17% with respiratory epithelium, 6% with. squamous and respiratory epithelium, 14% with inflammatory change. Lymphoid tissue was common(62%) in the wall of the lesions. Twelve(7%) of 158 patients had postoperative complications including wound complication, recurrence and facial nerve palsy.

• 한국대기환경학회지
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• 제21권6호
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• pp.573-583
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• 2005

Fugitive dust, which is emitted in the ambient air without first passing through a stack or duct designed to control flow, is frequently generated by means of wind erosion from storage yards at Pohang Steel Wokrs. The size distribution of fugitive dust is mostly in the range of coarse particulate which is deposited as soon as emitted and less harm to human health; however $20\%$ of fugitive dust contains PM 10 known as one of most harmful airborne pollutant. Consequently, effective control and reduction of fugitive dust is strongly requested by the local society, but it is not easy so far because the generation and dispersion of fugitive dust highly depends on meteorological conditions, and it being occurred for irregularity. This research presented a fugitive dust control system for each meteorological condition by providing statistical prediction data obtained from a statistical analysis on the probability of generating the threshold velocity at which the fugitive dust begins to occur, and the frequency occurring by season and by time of the wind direction that can generate atmospheric pollution when the dispersed dust spreads to adjacent residential areas. The research also built a fugitive dust detection system which monitors the weather conditions surrounding storage yards and the changes in air quality on a real-time basis and issues a warning message by identifying a situation where the fugitive dust disperses outside the site boundary line so that appropriate measures can be taken on a timely basis. Furthermore, in respect to the spraying of water to prevent the generation of fugitive dust from the storage piles at the storage yard, an advanced statistical meteorological analysis on the weather conditions in Pohang area and a case study of fugitive dust dispersion toward outside of working field during $2002\∼2003$ were carried out in order to decide an optimal water-spraying time and the number of spraying that can prevent the origin of fugitive dust emission. The results of this research are expected to create extremely significant effects in improving surrounding environment through actual reduction of the fugitive dust produced from the storage yard of Pohang Steel Works by providing a high-tech warning system capable of constantly monitoring the leakage of fugitive dust and water-spray guidance that can maximize the water-spraying effects.

• 한국산업보건학회지
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• 제16권3호
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• pp.290-301
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• 2006

A push pull hood system is frequently applied to control contaminants evaporated from an open surface tank. Efficiency of push pull hood system is affected by various parameters, such as, cross draft, vessel shapes, tank surface area, liquid temperature. A previous work assisted by flow visualization technique qualitatively showed that a strong cross draft blown from the pull hood to push slot could destroy a stable wall-jet on the surface of tank, resulting in the abrupt escape of smoke from the surface. In this study, the tracer gas method was applied to determine the effect of cross-draft on the capture efficiency qualitatively. A new concept of capture efficiency was introduced, that is, linear efficiency. This can be determined by measuring the mass of tracer gas in the duct of pull hood while the linear tracer source is in between push slot and pull hood. By traversing the linear tracer source from the push slot to the pull hood, it can be found where the contaminant is escaped from the tank. Total capture efficiency can be determined by averaging the linear efficiencies. Under the condition of cross-draft velocities of 0, 0.4, 0.75, 1.05 and 1.47m/s, total capture efficiencies were measured as 97.6, 95.4, 94.6, 92.7 and 70.5% respectively. The abrupt reduction of efficiency with cross-draft velocity of 1.47m/s was due to the destruction of tank surface wall-jet by the counter-current cross-draft. The same phenomenon was observed in the previous flow visualization study. As an alternative to overcome this abrupt efficiency drop, the 20% increase of hood flow rates was tested, resulting in 20% efficiency increase.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제13권2호
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• pp.153-159
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• 1991

외상성, 혹은 선천적 결손으로 인한 함몰부에 사용한 자가 유리지방 이식은 잘 알려진 방법이다. 이를 위해 사용되는 주된 공여부는 복부나 둔부의 피하지방이었다. 그러나, 1977 년 Egyedi는 협지방대를 유경피판으로 처음 사용하였다. 협지방대는 안면골 절단술시, 협측 피판을 들어올릴 때, 혹은 이하선관 수술 같은 구강내 수술시 항상 귀찮은 구조물로써, 수술 시야를 방해한다. 협지방대는 매우 세밀한 막으로 둘러싸인 소엽형태의 볼록한 물질로, body와 네 개의 prccess들로 구성된다. 이 돌기들은 여러 근육층 사이의 충전물로 작용하며, 유아에서는 sucking시 보조작용으로, 성인에서는 윤활재로 사용되기도 한다. 본 교실에서는 협지방대를 사용하여 세 증례의 협골 함몰부에, 그리고 한 증례의 비순구 재건을 위해 사용한 바, 양호한 결과를 얻었기에 문헌고찰과 함께 증례보고를 하는 바이다.

• BMB Reports
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• 제45권1호
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• pp.51-56
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• 2012

The purpose of this study was to determine the effects of duration and timing of glucocorticoid treatment on the expansion and differentiation of porcine neonatal pancreas cell clusters (NPCCs) into ${\beta}$-cells. After transplantation of NPCCs, the ductal cyst area and ${\beta}$-cell mass in the grafts both showed positive and negative correlations with duration of dexamethasone (Dx) treatment. Pdx-1 and HNF-3${\beta}$ gene expression was significantly downregulated following Dx treatment, whereas PGC-1${\alpha}$ expression increased. Pancreatic duct cell apoptosis significantly increased following Dx treatment, whereas proliferation did not change. Altogether, transdifferentiation of porcine NPCCs into ${\beta}$-cells was influenced by the duration of Dx treatment, which might have been due to the suppression of key pancreatic transcription factors. PGC-1${\alpha}$ plays an important role in the expansion and transdifferentiation of porcine NPCCs, and the initial 2 weeks following transplantation of porcine NPCCs is a critical period in determining the final ${\beta}$-cell mass in grafts.

• 한국기계가공학회지
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• 제19권2호
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• pp.24-29
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• 2020

In South Korea, agricultural mechanization has been carried out in paddy field, but not in the upland field during recent decades. Among crops such as root vegetables, leafy vegetables from upland field, corn is used as forage for livestock as well as food for men. The corn harvester needs to be developed to replace men's labor in rural area to follow the recent needs in the farm industry. The corn harvester is comprised of three parts such as cutting part, feeding part and pick-up part. The feeding part is so long for cut corns to be delivered from the cutting part to the pick-up part. Structurally, the load from the long moment arm is likely to be big. Thus, the setup to measure the stress on the duct of the feeding part was configured with the data acquisition system. The strain gages were attached on several points that seem to be loaded a lot comparatively. The stress was measured and the measured stresses were divided by the yield stress to get the safety factor. And then, we made sure the safety factors were above 1 on the all points. In conclusion, the feeding part of the corn harvester which convey the cut corn from the cutting part from the pick-up part can be regarded to be made safe structurally.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1163-1168
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• 2016

Cholangiocarcinoma (CCA) is the bile duct cancer which constitutes one of the important public health problems in Thailand with high mortality rate, especially in the Opisthorchis viverrini (a parasite risk factor for CCA) endemic area of the northeastern region of the country. This study aimed to identify potential biomarkers from the plasma peptidome by CCA patients. Peptides were isolated using 10 kDa cut-off filter column and the flow-through was then used as a peptidome for LC-MS/MS analysis. A total of 209 peptides were obtained. Among these, 15 peptides were concerned with signaling pathways and 12 related to metabolic, regulatory, and biosynthesis of secondary metabolite pathways. Five exclusive peptides were identified as potential biomarkers, i.e. ETS domain-containing transcription factor ERF (P50548), KIAA0220 (Q92617), phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit beta isoform isoform 1 (P42338), LP2209 (Q6XYC0), and casein kinase II subunit alpha (P19784). Three of these biomarkers are signaling related molecules. A combination of these biomarkers for CCA diagnosis is proposed.

• Archives of Plastic Surgery
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• 제38권3호
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• pp.251-256
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• 2011

Purpose: A nasolabial cyst is a rare non-odontogenic, soft-tissue, developmental cyst arising anywhere on the face inferior to the nasoalar region. It is thought to arise from either epithelial remnants trapped along the lines of fusion during the development of face or the remnants of the developing nasolacrimal duct. This study examines various features of nasolabial cysts with bony involvement to provide a basis for correct diagnosis and treatment. Methods: Eight cases of nasolabial cyst treated in Soonchunhyang Hospital between March 2002 and July 2010 were examined in terms of their clinical features and radiological and histological findings. Seven patients underwent surgical excision of the cyst via an intraoral, sublabial approach. One underwent incision and drainage. Results: Our eight patients were seven women and one man. The most frequent symptoms and signs were facial deformity and swelling of the nasolabial fold. Computed tomography (CT) showed a well-circumscribed cystic mass lateral to the pyriform aperture. Seven cases had erosive lesions on CT, and the intraoperative findings were consistent with a nasolabial cyst with a bony defect. Typical histopathological findings showed that these cysts were most frequently lined with respiratory epithelium with ciliated columnar cells and cuboid cells. No patient developed complications or recurrences. Conclusion: A nasolabial cyst is often unrecognized or confused with other intranasal masses, including fissural and odontogenic cysts, midface infections, or swelling in the nasolabial area. Therefore, a careful clinical and radiological evaluation should be preformed when considering the differential diagnosis. We present eight patients with nasolabial cysts treated via a gingivobuccal approach with excellent functional and cosmetic results.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제3권1호
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• pp.47-55
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• 2000

Purpose: The aim of this research is to examine the abnormal liver function complicated with Kawasaki disease (KD) and to analyze its clinical characteristics and complications. Methods: Ninty eight cases were diagnosed as having KD, among which thirty four cases had abnormal alanine aminotransferase (ALT) (>30 IU/L). These abnormal ALT cases were evaluated in terms of age and sex distribution, major symptoms, complications, laboratory and histopathologic findings. Results: Male to female ratio was 2.4:1 and most patients (91.2%) were under 5 years of age. Cervical lymphadenopathy was observed in 3 cases (8.8%); and recurred cases were two (5.8%). Average fever duration was 8 days; average length of hospitalization was 9 days; and average recovery period was 13 days. Immediately after admission, positive CRP was observed in 31 cases (91.2%), leukocytosis (> $10,000/mm^3$) in 26 cases (76.0%), thrombocytosis (> $450,000/mm^3$) in 7 cases (20.6%), and anemia (<10 gm/dl) in 7 cases (20.6%), respectively. GB hydrops or cholecystitis were noted in 3 cases (8.8%), abnormal ECG finding in 1 case (2.9%), coronary dilatation or aneurysm in 2 cases (5.9%). Liver biopsy was done in four cases and revealed mild infiltration of lymphocytes on the portal area and mild bile duct proliferations. Conclusion: The abnormal liver function was noted in 34.7% of KD patients, and subsided all within one month. But the liver function test should be checked closely in patients of the abnormal liver function test complicated with KD despite of its good prognosis.