• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.4
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• pp.267-270
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• 2012

Lipoma is the most common benign neoplasm of the body with rare occurrence in the oral cavity. It represents 1~4% of benign neoplasms of the mouth, which affect the buccal mucosa, floor of the mouth, tongue and lips. We report a case of lipoma in the labial vestibule with extraoral swelling, which could easily be misdiagnosed as an odontogenic abscess. Excisional biopsy in this case revealed well-circumscribed masses, surrounded by a thin fibrous capsule and composed of sheets of mature adipocytes, arranged in a "chicken wire" configuration. After a computed tomography scan, excisoinal biopsy was done, and there were no recurrence after 5-month follow-up period.

• Journal of Chest Surgery
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• v.26 no.12
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• pp.965-968
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• 1993

Primary benign tracheal tumors are exceedingly rare and leiomyoma has the least frequency among them. It is important to recognize early without misdiagnosis such as asthma because it is curable. A 41 year-old female was admitted for dyspnea and choking since November 1991. Under the impression of asthma, she received medication. Symptom was not improved and thus chest CT scan was performed. There was endotracheal tumor mass which was located just above the carina and arose from the right lateral tracheal wall with broad base. We successfully resected the tumor mass including trachea and the defected area of trachea was reconstructed with autologous graft using pericrdium & rib cartilage. During the follow up period, no complication was developed.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.294-295
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• 2017

태양광발전시스템은 설비 사용률을 최대화하기 위하여 PV 모듈을 최대 전력점에서 운전하는 MPPT(Maximum Power Point Tracking) 제어가 반드시 필요하다. 기존의 MPPT 알고리즘은 경사법에 기반을 두기 때문에 일정한 MPPT 주기마다 일정한 크기의 PWM Duty 비의 자극을 주고, 그에 따른 출력 전력의 변화를 감지하여 최대 전력점을 향한 다음 운전점을 찾는다. 이러한 MPPT 알고리즘을 실제 날씨 환경에 적용할 때 최대전력을 생산하기 위한 최적의 MPPT 주기와 PWM Duty 비의 변량은 다양한 일사량의 프로파일 형태에 따라 달라진다. 그러므로 최적의 MPPT 주기와 PWM Duty 비의 변량을 결정하기 위해서는 실제 날씨 환경에서 다양한 일사량 프로파일의 패턴에 대한 분석이 필수적이다. 본 논문에서는 대한민국 중부지역의 전형적인 맑은 날씨와 흐린 날씨에서 실제 일사량을 측정, 분석하여 MPPT 목표 효율을 최대화할 수 있는 MPPT 주기를 제시하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1391-1392
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• 2007

A selective reset waveform which can improve the dark room contrast ratio in a large sustain gap structure is suggested in this paper. When conventional selective reset discharge is performed, frequent unexpected misfiring happens because of high Vxb and much quantity of negative wall charge formed on Y electrode during final sustain period. The misfiring between sustain electrode and address electrode can be removed by lowering Vxb value and the misfiring between address electrode and scan electrode can be prevented by applying last sustain pulse of 40us and rectangular pulse of Vscan on Y electrode. When the selective reset waveform has one time reset per 8 subfields, black luminance of 1.55 cd/m2 can be obtained without any misfiring.

• Korean Journal of Veterinary Research
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• v.61 no.4
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• pp.35.1-35.4
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• 2021

Following intravenous (IV) administration of diazepam as a preanesthetic agent, sudden balance impairment, such as falling, leaning, and rolling, was identified in 2 canine cases. The 2 dogs were anesthetized for brain magnetic resonance scan to diagnose about a history of head tilt. After end of the diagnostic procedures, during the anesthetic recovery period, balance impairment was also observed. However, the symptoms gradually ceased by IV administration of flumazenil. These 2 canine cases indicated that diazepam premedication was responsible for the acute balance impairment.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.451-458
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• 1999

Purpose : To determine normal CT number range of parotid gland by analyzing the change by age increase and the difference among individuals and between both sexes in CT number of normal parotid gland. Materials & Methods : 134 subjects who took the CT scan between the period of Jan. 1996 and Dec. 1997 at Yonsei University, Dental Hospital were selected. Criteria for selection were that the patients must be within the normal range clinically and radiologically, and the entire parotid gland on the axial view must be shown. Among the axial views. the one showing the greatest parotid gland size was selected and its CT number was recorded. Also. CT numbers from both masseter muscle were recorded as its control. Results : There was statistically significant correlation between CT number of right and left of parotid glands and masseter muscles. With the increase of age. there is a significant decrease in the CT number of parotid gland(p<0.05). There was no statistically significant difference in CT number between sexes except the 7th decade and beyond age group of parotid gland(p>0.05). Conclusion : As age increases, CT number of parotid gland has a tendency to decrease, and there is no significant difference in the CT numbers between left and right parotid gland. Therefore in the CT scan of patients suspected of having a salivary gland disease of the parotid gland. to consider normal range of the age-dependent CT numbers of parotid gland and compare the CT numbers of the right and left parotid gland might be useful in diagnosing the disease.

• Journal of the Korean Electrochemical Society
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• v.14 no.4
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• pp.214-218
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• 2011

The electrochemical characteristics and performance of redox flow battery using the soluble lead has been evaluated. Cyclic voltammetry was performed on the materials to evaluate deposition and dissolution of lead and lead dioxide. In the negative region, a reduction peak is not observed, and on the reverse scan, on-set voltage is observed at -0.47 V(vs SCE). In the positive region, the distinct peak is observed on the forward and reverse scan. The charge/discharge experiments were carried out graphite electrode in the beaker cell. The charging(deposition) of lead occurs at around 0.5 V(vs SCE) and discharging(dissolution) of lead occur at around 0.25 V(vs SCE). The potential difference is about 0.25 V. The charging(deposition) of dioxide lead is at 1.77 V(vs SCE) and discharging(dissolution) is at around 0.95 V(vs SCE) during first cycle. On subsequent cycles, the charging of dioxide lead starts at below 1.5 V(vs SCE), after a period the voltage increase to 1.7 V(vs SCE). The voltage of discharging is stable at around 1.0 V(vs SCE).

• Journal of Preventive Medicine and Public Health
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• v.49 no.4
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• pp.230-239
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• 2016

Objectives: We aimed to evaluate the effect of geographic units of analysis on measuring geographic variation in medical services utilization. For this purpose, we compared geographic variations in the rates of eight major procedures in administrative units (districts) and new areal units organized based on the actual health care use of the population in Korea. Methods: To compare geographic variation in geographic units of analysis, we calculated the age-sex standardized rates of eight major procedures (coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, surgery after hip fracture, knee-replacement surgery, caesarean section, hysterectomy, computed tomography scan, and magnetic resonance imaging scan) from the National Health Insurance database in Korea for the 2013 period. Using the coefficient of variation, the extremal quotient, and the systematic component of variation, we measured geographic variation for these eight procedures in districts and new areal units. Results: Compared with districts, new areal units showed a reduction in geographic variation. Extremal quotients and inter-decile ratios for the eight procedures were lower in new areal units. While the coefficient of variation was lower for most procedures in new areal units, the pattern of change of the systematic component of variation between districts and new areal units differed among procedures. Conclusions: Geographic variation in medical service utilization could vary according to the geographic unit of analysis. To determine how geographic characteristics such as population size and number of geographic units affect geographic variation, further studies are needed.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.189-193
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• 2013

Objective : It remains debatable whether cervical spine fusion cages should be filled with any kind of bone or bone substitute. Cortical and subcortical bone from the anterior and posterior osteophytes of the segment could be used to fill the cage. The purposes of the present study are to evaluate the clinical outcomes and radiological outcomes including bone fusion and subsidence that occurred after anterior cervical discectomy and fusion using a stand-alone cage packed with local autobone graft. Methods : Thirty-one patients who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage packed with local autobone graft from July 2009 to december 2011 were enrolled in this study. Bone fusion was assessed by cervical plain radiographs and computed tomographic scan. Nonunion was evaluated according to the absence of bony bridge on computed tomographic scan. Subsidence was defined as a ${\geq}2$ mm decrease of the interbody height at the final follow-up compared to that measured at the immediate postoperative period. Results : Subsidence was observed in 7 patients (22.6%). Of 7 patients with subsidence greater 2 mm, nonunion was developed in 3. Three patients with subsidence greater 2 mm were related with endplate damage during intraoperative endplate preparation. Solid bone fusion was achieved in 28 out of 31 patients (90.3%). Conclusion : With proper patient selection and careful endplate preparation, anterior cervical discectomy and fusion (ACDF) using a stand-alone PEEK cage packed with local autobone graft could be a good alternative to the standard ACDF techniques with plating.

• Journal of Yeungnam Medical Science
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• v.25 no.2
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• pp.160-164
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• 2008

A two-month-old girl with a history of an incidental arachnoid cyst in the prenatal period (38 weeks) presented with persistent irritability. A follow-up computed tomographic (CT) scan revealed an enlarged arachnoid cyst with hydrocephalus. We performed craniotomy and fenestration, but the cyst size did not decrease, and hydrocephalus had worsened on a follow-up CT scan performed 13 months after fenestration. The patient was treated with cystoperitoneal shunting. Follow-up magnetic resonance imaging (MRI) performed 5 years later revealed that the arachnoid cyst had decreased in size and that the hydrocephalus had resolved. Enlarging arachnoid cysts are not common, and optimal surgical treatment is uncertain. Based on the features of this case, we believe cystoperitoneal shunting is an advisable surgical intervention for patients with enlarging arachnoid cysts presenting with hydrocephalus.