성인의 경부 전면 중앙부위에서 발생한 기형종 1예

최월용,정효진,채종인,하태인,정상렬,이광재,채병도,최영식 고신대학교 의학부 2004 高神大學校 醫學部 論文集 Vol.19 No.1

Teratomas are embryonal neoplasms that show characteristics of three germ cell layers(ectoderm, mesoderm, and endoderm). They are distributed in the following regions: sacrococcygeal(57%), gonadal(29%), mediastinal(7%), cervical(3%), retroperitoneal(4%), and intracranial(3%) regions. Non-gonadal treatomas present in infancy whereas gonadal are seen in adolescence. Especially, teratomas that occurred in midline neck of adult are very rare and are confused with thyroglossal duct cysts, cystic hygromas, and thyroid tumors. We report, along with the review of appropriate literature, a case of histopathologically confirmed benign teratoma in the midline neck of a 33 years old woman.

해면효과익의 실험적 연구와 PARWIG선의 설계 및 제작

장종희,전호환,정광효,이 준 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.53 No.-

지면효과(Wing In Ground Effect, WIG)의 개념은 날개가 지면 가까이 비행할 때 유기저항(Induced drag)의 감소와 양력의 증가로 양항비가 증가하는 것이다. 이러한 효과를 이용하여 지면 또는 해면 가까이 항주함으로서 해면효과익선이 같은 속도의 비행기보다 경제성이 좋은 것으로 평가되어지고 있다. 또한 PAR(Power Augmented Ram)현상은 1970년대경 발견된 것으로서 날개 앞에 부착된 프로펠러의 후류를 날개 밑으로 불어넣어 해면효과익선이 저속에서도 이수할 수 있도록 하여 WIG선의 성능을 향상시키는 계기가 되었다. 본 논문은 풍동을 이용하여 지면에서 날개후연까지 높이의 변화, 앙각의 변화 및 날개끝단판(End- plate)의 변화에 따른 날개의 양력, 항력 및 종방향모멘트를 계측하여 분석하고 2.5m급 무선 조종 PARWIG선의 설계개념과 제작과정에 대해서 설명한다. In the early of the 20th century, it was noted that a wing operating in close proximity to the ground exhibits a reduction in induced drag, which increases its lift/drag ratio. For several decades this phenomenon, called the wing-in-ground-effect(WIG), was studied because it complicated the takeoff and landing of aircraft. In the 1970s, the Power Augmented Ram(PAR) phenomenon was discovered, which significantly enhanced the performance of the WIG concept. The main purpose of this study is to design a 2.5m size, remote control PARWIG model aiming to develop an one manned leisure PARWIG craft. The lift and drag force are measured in a wind tunnel for wings with different flying heights, angles of attack and endplates. Based on the experimental results, 2.5m size model craft is designed and constructed.

증발 표면적 증대를 위한 수적 분리기 특성에 관한 연구

모종근,공태우,이광영,정효민,정한식,서정세 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-

The purpose of this research is to obtain the characteristics of water-vapor separator for improving the evaporative surface. The experimental system is constituted with water vapor generator, vapor storage tank, laser source for visualization and camera for photography. The efficiency of water-vapor separator can be varied by the kinds of the inside materials. Thus, in this report, we introduced the three kinds of materials with wire scrap, wire brush and sponge. As the experimental results, the wire brush was showed the best efficiency with 185 g/hr.

혈액투석 중인 만성 신부전 환자에서 G 형 간염 바이러스의 감염률 및 임상적 의의

최규완,백승운,김정룡,이준혁,고광철,이종철,이윤하,김윤구,오하영,이효석 대한소화기학회 1999 대한소화기학회지 Vol.33 No.1

Background/Aims: We aimed to elucidate the prevalence and risk factors of HGV infection in patients with chronic renal failure undergoing hemodialysis, and to define the potential etiologic-role of HGV in the development of chronic liver disease. Methods: One-hundred and seventy-eigh patients with chronic renal failure undergoing hemodialysis were included. After extraction of RNA from serum, reverse transcription polymerase chain reaction was performed using the primers from the NS5a region. The PCR products were analyzed by liquid hybridization. Results: The prevalence was 9.0% (16/178). The prevalence rates were not statistically different according to the presence (8.5%) or abscence (10.8%) of past history of blood transfusion, patient's age or maintenance duration of hemodialysis (p$gt;0.05). Anti-HBc-positive patients (12.4%, 16/129) showed significantly higher prevalence rate (p=0.01) of HGV infection than anti-HBc-negative patients (0%, 0/49). Twelve of the 14 HGV positive patients without co-infection showed persistently normal ALT level during a year of follow-up. Conclusions: The prevalence of HGV in patients with chronic renal failure undergoing hemodialysis is significantly higher than that of volunteer blood donors. HGV may share the route of transmission with adulthood HBV infection. The etiologic-role of HGV in the development of chronic liver disease may be considerably poor. (Kor J Gastroenterol 1999;33:78 - 89)

'1998 한국인 우울증 선별의 날' 참가자들의 사회인구통계학적 특성과 우울증 선별검사 결과

한상익,이성필,고효진,박원명,장계호,유태열,전태연,채정호,방승규,김광수,최보문,이정태,백인호 大韓神經精神醫學會 1999 신경정신의학 Vol.38 No.5

연구목적 : 1998년 정신건강의 날 기념 한국인 우울증 선별의 날 행사에 자발적으로 참여한 참가자들의 사회인구 통계학적 특성을 분석하고 우울증 선별검사 결과를 평가하기 위하여 본 연구를 시행하였다. 방 법 : 8개 병원에서 얻어진 619명의 자료를 사용하여 선별검사로 밝혀진 우울증의 유병율과 사회인구통계학적 특성 및 응답자의 정신과적 치료를 포함한 과거력 등을 조사하였다. 결 과 : 우울증 척도 점수는 응답자 전체 평균 57.5±13.8로 경도의 우울 증상이 있는 것에 해당되었다. 전체 응답자의 69.5%(430명)가 최소한 경도 이상의 우울 증상을, 43.1%(267명)가 중등도 이상의 우울 증상을, 18.4%(114명)가 고도의 우울 증상을 보였다. 고도의 우울 증상이 있는 응답자의 56.8%와 중등도의 우울 증상이 있는 응답자의 63.9%가 정신과 치료를 받은 적이 전혀 없었다. 나이가 29세 이하인 것과 전임근무 중인 직업상태는 각각 나이가 60세 이상인 것과 직업이 없는 것에 비교하여 우울증으로부터 보호하는 인자임을 시사하였다. 결 론 : '1998 한국인 우울증 선별의 날' 행사를 통하여 많은 우울증 환자들을 선별해낼 수 있었고, 이들의 우울 증상은 몇몇 사회인구통계학적 특성과 유의한 관계가 있음을 확인하였다. 우울증 선별의 날 행사를 통한 우울증에 대한 교육과 우울증 선별검사는 치료받지 못하고 있는 우울증 환자 및 기존의 치료 중인 환자 모두에게 유용한 프로그램임을 알 수 있었다. Objectives : This study was performed to analyze the sociodemographic characteristics of participants in '1998 Korean Depression Screening Day' and to evaluate the results of the screening test. Methods : By using the survey results of 619 volunteers from 8 hospitals, the authors examined the prevalence of depression detected at the screening test and sociodemographic characteristics and the psychiatric treatment history of respondents. The assessment measure was the Zung Self-Rating Depression Scale. Results : The mean depression score of all participants was 57.5±13.8 and it came under mild depression. Of all participants, 69.5%(N=430) had at least mild depressive symptoms, 43.1%(N=267) had at least moderate symptoms, and 18.4%(N=114) had severe symptoms. Never have 56.8% of respondents in the severely depressed range and 63.9% of those in the moderately depressed range had psychiatric treatment. The results suggest that the age group of 29-year-old or younger(relative to 60-year-old or older group) and full-time employment status(relative to unemployment) are protective factors of depression. Conclusions : By '1998 Korean Depression Screening Day', many depressed patients were detected and their depressive symptoms had statistically significant relationships with some sociodemographic characteristics. The results suggest that the education and screening test programs for depressive illness facilitated by Depression Screening Day are useful to the patients regardless of being under current treatment or not.

Three-Dimensional Flow in a Container with Horizontally Non-Uniform Temperature Boundary Conditions

Kwang Hyo Chung,Ho Sang Kwak,Jae Min Hyun 대한기계학회 1998 KSME/JSME THERMAL and FLUID Engineering Conference Vol.1 No.1

와류 격자법에 의한 지면효과익의 성능 연구

정광효(Kwang-Hyo Chung),장종희,전호환(Ho-Hwan Chun) 한국해양공학회 1998 韓國海洋工學會誌 Vol.12 No.2

A numerical simulation was done to investigate the performance of thin wings in close vicinity to ground. The simulation is based on Vortex Lattice Method(VLM) and freely deforming wake elements are taken into account for a sudden acceleration case. The parameters covered in the simulation are angle of attack, aspect ratio, ground clearance, sweep angle and taper ratio. In addition, the effect of the wing endplate on the ground effect is included. The wing sections used for present computations are uncambered, cambered and S-types. The present computational results are compared with other published computational results and experimental data.

Better Efficacy of Balloon Assisted Maturation in Radial-Cephalic Arteriovenous Fistula for Hemodialysis

Hyo Kee Kim,Ahram Han,Sang Hyun Ahn,고현민,Chris Tae Young Chung,Kwang Woo Choi,Sang-Il Min,Jongwon Ha,Seung-Kee Min 대한혈관외과학회 2021 Vascular Specialist International Vol.37 No.1

Purpose: Native arteriovenous fistula (AVF) is the first choice for hemodialysis access; however, the maturation failure rate remains high. Hence, balloon-assisted maturation (BAM) is increasingly being used to overcome maturation failure. This study evaluated the outcomes of BAM and compared the differences between radial-cephalic (RC) and brachial-cephalic (BC) AVF. Materials and Methods: Between January 2013 and December 2017, 1,622 new AVFs were created. BAM was considered if the AVF did not satisfy the criteria for hemodynamic maturation (6-mm diameter and 500-mL/min flow rate within 8 weeks after the operation). Results: Of the 1,622 AVFs, BAM was performed in 142 patients (8.75%). There were 92 RC and 50 BC AVFs. Multivariate analyses revealed that ipsilateral central vein catheter history was the sole risk factor for maturation failure after BAM. Oneyear functional primary patency (FPP) and functional secondary patency (FSP) in RC AVFs were higher than those in BC AVFs without statistical significance (FPP, RC vs. BC: 70.9% vs. 50.9%, P=0.099; FSP, 95.5% vs. 81.1%, P=0.146). Further, based on the multivariate analysis, the independent risk factors for FPP in the RC and BC AVFs were the number of BAMs (odds ratio [OR], 3.05; 95% confidence interval [CI], 1.11-8.37; P=0.03) and age (OR, 1.04; 95% CI, 1.00-1.07; P=0.04), respectively. Conclusion: BAM is a relatively good salvage method with tolerable patency. However, the risk factors for patency and the outcomes of BAM differ between RC and BC AVFs.

Articles : Structural Change of Polydomain in the Liquid Crystalline Polymers by Weak Shear Flow

( Kwang Man Kim ),( Tae Kyun Kim ),( Sang Hyo Kim ),( In Jae Chung ) 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.1

Steady-state shear stress (τ-_(12)) and first normal stress difference (N₁) of liquid crystalline polymers at low shear rates were examined by using a mesoscopic constitutive equation set including the idea of initial domain size. For the applicability to the weak shear flow at low shear rates, a Hinch-Leal closure approximation was adopted in the calculation of the constitutive equation set. The steady-state rheological behaviors predicted by adopting the Hinch-Leal approximation were compared with those by the Doi simple decoupling approximation. It could be predicted from the plot of N₁, versus τ-_(12) that smaller domains distributed isotropically at a quiescent state might maintain the isotropic domain distribution even at the imposition of moderate shear rate, and then could be changed to the ordered (or partially elongated) domain phase by a further increase of shear rate. Such change of the polydomain structure with the increase in shear rate could be proved more precisely by the transient rheological behaviors of N₁, and τ-_(12) after the start-up of shear flow.

Efficacy of a novel channel-cleaning ball brush for endoscope reprocessing: a randomized controlled trial

Kwang Hyun Chung,Jeong Don Chae,Wonho Choe,Hyo Young Lee,Il Hwan Oh,Byoung Kwan Son 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.5

Background/Aims: Endoscopic channels are difficult to clean and can cause infection transmission. We examined the effectiveness of a newly developed channel-cleaning ball brush (BB), which is sucked into the endoscopic channel and scrapes and cleans the lumen as it passes through. Methods: The upper and lower gastrointestinal endoscopes used for patient examinations were randomly selected as the conventional brush (CB) or BB group. After manual cleaning, the presence or absence of carbohydrates, proteins, adenosine triphosphate, and he- moglobin was assessed. Results: Fifty-six and 58 endoscopes were cleaned with the CB and BB, respectively. Carbohydrate and protein were detected in one (1.8%) and two endoscopes (3.4%) in the CB and BB groups, respectively (p=1.000). Hemoglobin was observed in one (1.8%) and three endoscopes (5.2%) in the CB and BB groups, respectively (p=0.636). The adenosine triphosphate levels were 10.6±15.9 and 12.5±14.3 relative light units in the CB and BB groups, respectively (p=0.496). Twenty-seven (48.2%) and 19 (32.8%) endoscopes were positive for microbial cultures in the CB and BB groups, respectively (p=0.136). Conclusions: The efficacy of BB was not significantly different from that of CB in the endoscopic channel-cleaning process.