• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1161-1166
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• 2009

Purpose : Kawasaki disease—the most common cause of acquired heart disease in children—incidence is increasing yearly. Therefore, we evaluated the predictive indicators of coronary complications of Kawasaki disease based on clinical and laboratory data. Methods : Between January 2005 and March 2008, of the 201 children with Kawasaki disease treated at the Gil Hospital of Gachon University of Medicine and Science, 51 had coronary artery lesions (Group II) and 150 had no lesions (Group I). The reasons for coronary artery lesions were deduced from the clinical and laboratory data. Results : Analysis of the 2 groups revealed that fever duration and days of fever after and before initial intravenous gammaglobulin (IVIG) treatment were significantly longer in Group 2 than in Group I. IVIG infusions were statistically higher in Group II than in Group I. As per the laboratory data, C-reactive protein (CRP) value was significantly higher in Group II. Collectively, >10 days of fever duration, >48 h of fever duration after, and >10 days of fever before IVIG treatment increased the risk of coronary artery lesions 6-, 5-, and 3.5-fold, respectively. Furthermore, additional IVIG courses and higher CRP level increased the risk of coronary artery lesions 4-fold and 2-3-fold, respectively. Conclusion : The following 3 factors were responsible for increased risk of coronary artery lesions in children with Kawasaki disease: fever duration and days of fever after and before IVIG treatment. To identifythe predictive indicators of coronary complications, it is necessary to further elucidate the relationship between well-known forecasting factors.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.197-206
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• 2006

This study evaluated the effect of ultrasonic irradiation on improving the flux and cleaning efficiency in membrane process which is widely applied for the treatment of landfill leachate. The experiments on improvement of membrane flux according to the types of membranes(hallowfiber microfiltration, MF and tubular ultrafiltration, UF) were performed with changing frequency($40{\sim}120$ kHz), intensity ($200{\sim}500$ W) and irradiation time of ultrasound as well us operation pressure($0.1{\sim}2.3kg/cm^2$). Membrane was fouled for the first 50 min with primary treated leachate and then the change in flux according to ultrasonic irradiation period was observed for 70 min. Parameters influenced to the recovery ratio corresponding the net flux on pure water and to the enhancement ratio applied after ultrasonic irradiation on the flux were analyzed. In same condition, the flux was improved in proportion to ultrasonic intensity while the improvement of flux was inversely proportional to ultrasonic frequency. The cleaning effect of membrane was delayed and reduced when operation pressure of membrane was high. The recovery ratio and enhancement ratio for $0.1{\mu}m$ MF membrane were 10% and 500%, respectively while those were maximized at $75{\sim}98%\;and\;40{\sim}50%$ for UF membrane for 10,000 and 100,000 MWCO, respectively. In conclusion, it was confirmed that ultrasonic cleaning using mechanical vibration is alternative to water or chemical cleaning for improving membrane flux.

• Journal of Life Science
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• v.21 no.1
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• pp.22-30
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• 2011

Apolipoprotein A-I (apoA-I) has anti-inflammatory and anti-oxidative properties. This study was designed to investigate whether apoA-I affects apoptosis and cytokine production of human blood neutrophils in an in vitro culture system. Spontaneous apoptosis of neutrophils was significantly delayed by apoA-I. In addition, high density lipoprotein containing apoA-I also delayed apoptosis of neutrophils. Apoptosis of neutrophils was inhibited by anti-scavenger receptor type B-I antibodies. The amounts of interleukin-8, interferon (IFN)-inducible protein 10 (IP-10), and tumor necrosis factor-$\alpha$ (TNF-$\alpha$) in the supernatants of cultured neutrophils treated with apoA-I were significantly increased. Combined treatment of neutrophils with IFN-$\gamma$ and apoA-I produced higher amounts of IP-10 and TNF-$\alpha$ than did treatment with IFN-$\gamma$ or apoA-I alone. The present study reveals that apoA-I activates neutrophils to produce cytokines and delays spontaneous apoptosis of neutrophils. These findings suggest that apoA-I, although a well-known negative acute-phase protein, has a pro-inflammatory effect in neutrophils.

• The Journal of the Acoustical Society of Korea
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• v.36 no.5
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• pp.361-369
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• 2017

Hemodynamic information in the carotid artery bifurcation is very important for understanding the development and progression mechanisms of cerebrovascular disease and for its early diagnosis and prediction of the progress. In this paper, we constructed a mock pulsatile blood circulation system using an anthropomorphic elastic vessel of the carotid artery bifurcation and ex vivo pig blood to acquire ultrasound images from blood and vessels synchronized with internal pressure while controlling the blood flow. Echogenicity, blood flow velocity, and blood vessel wall motion from the ultrasound images, and internal blood pressure were extracted over a cycle averaged from five cycles when the pulsatile pump rates are 20 r/min, 40 r/min, and 60 r/min. As a result, respectively, the peak systolic blood flow velocities were 20 cm/s, 25 cm/s, and 40 cm/s, the blood pressure differences were 30 mmHg, 70 mmHg, and 85 mmHg, the arterial walls were expanded to 0.05 mm, 0.15 mm, and 0.25 mm. Time-delayed cyclic variation of echogenicity compared to blood flow and pressure was observed, but the variation was minimal at 20 r/min. Time-synchronized cyclic variations of these parameters are important information for accurate input parameters and validation of the computational hemodynamic experiments which will provide useful information for the development and progress mechanisms of carotid artery stenosis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.10-10
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• 2000

램제트 엔진은 비추력이 높고 추력 레벨은 낮으므로, 2단 추진기관에 적합한 추진 시스템이다. 1단-추진기관의 작동이 끝나고, 2단 램제트 엔진이 점화 후 안정된 연소에 도달되기까지 비행체의 속도는 항력에 의하여, 초당 약 마하수 0.1 정도씩 감소된다. 1단 연소 후 2단 램제트로 전환되는 지연시간이 길수록 1단에서 요구되는 종말 가속도는 증가되므로, 1단이 차지하게되는 부피는 증가되고 비행체의 크기 또한 늘어나게 된다. 따라서 1단에서 2단 램제트로 천이되는데 소요되는 시간을 가능한 짧게 하는 것이 효과적이다. 그러나 램제트 엔진의 특성상 선결되어야할 다음과 같은 여러 문제들이 있다. 첫째, 1단 작동 시 공기 흡입구와 연소실은 차단벽으로 분리되어 있다가, 1단 연소후 차단막이 제거되어 외부공기가 램제트 연소실로 흡입된다. 흡입되는 공기는 흡입구의 형상에 의하여 램 압축되지만 초음속으로 연소실을 통과하게된다. 연료 주입 구에서 공급되는 연료는 연소실에서 유동의 흐름방향(streamline)에 따라서 연소실로 확산되는데, 연소되기 전에는 유속이 빠르게 노즐로 빠져 나가므로 램제트 연료가 재순환 구역(recirculation zone)으로 침투하는데 쉽지가 않다. 둘째, 연소실 입구에서 발생되는 와류 (ring vortex)는 1단 연료의 고온 연소 가스를 연소실로 확산시키는데, 비 균일한 온도 분포를 유발하여 램제트 연료의 점화에너지가 공급되는 시간이 적당하지 않을 경우 균일한 화염 전파에 악영향을 준다. 셋째, 연소실에서의 빠른 유동 조건은 연료가 연소실에 머무를 수 있는 시간을 감소시키며, 연소실 입구에서 강한 전단 응력이 발생되어 화염이 안정화되는데 악 영향을 미치게된다. 본 논문은 공기 흡입구, 연소실 및 노즐을 통합하여 수치해석을 하였으며 열유동/점화/연소등의 미케니즘을 이해하고, 주요 인자들 중 와류의 영향에 초점을 맞추었다.다고 판단되며 배기 가스 자체에 대기 공기중에 함유되어 있던 습기가 얼어붙는(Icing화) 문제가 발생하기 때문에 배기가스의 Icing을 방지하기 위하여 압축기 끝단에서 공기를 추출하여 배기부분에 송출할 필요성이 있는 것으로 판단되었다. 출구가스의 기체 유동속도가 매우 빠르므로 (100-l10m.sec) 이를 완화하기 위한 디퓨저의 설계가 요구된다고 판단된다. 또 연소기 후방에 물을 주입하는 경우 열교환기 및 기타 부분품에 발생할 수 있는 부식 및 열교환 효율 저하도 간과할 수 없는 문제로 파악되었다. 이러한 기술적 문제가 적절히 해결되는 경우 비활성 가스 제너레이터는 민수용으로는 대형 빌딩, 산림, 유조선 등의 화재에 매우 적절히 사용되어 질 수 있을 뿐 아니라 군사적으로도 군사작전 중 및 공군 기지의 화재 그리고 지하벙커에 설치되어 있는 고급 첨단 군사 장비 등의 화재 뿐 아니라 대간첩작전 등에 효과적으로 활용될 수 있을 것으로 판단된다.가 작으며, 본 연소관에 충전된 RDX/AP계 추진제의 경우 추진제의 습기투과에 의한 추진제 물성 변화는 미미한 것으로 나타났다.의 향상으로, 음성개선에 효과적이라고 사료되었으며, 이 방법이 편측 성대마비 환자의 효과적인 음성개선의 치료방법의 하나로 응용될 수 있으리라 생각된다..7%), 혈액투석, 식도부분절제술 및 위루술·위회장문합술을 시행한 경우가 각 1례(2.9%)씩이었다. 13) 심각한 합병증은 9례(26.5%)에서 보였는데 그중 식도협착증이 6례(17.6%), 급성신부전증 1례(2.9%), 종격동기흉과 폐염이 병발한 경우와 폐염이 각 1례(2.9%)였다. 14) 식도경 시행회수는 1회가 17례(54.8%), 2회가 9례(29.0%), 3회 이상이 5례(16.1%)였다.EX>$IC_{50}$/ 값이 210 $\mu\textrm{g}$/$m\ell$로서 효과적

• Journal of Chest Surgery
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• v.41 no.3
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• pp.347-353
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• 2008

Background: Esophageal perforation is an emergency that. requires early diagnosis and effective treatment. A delay in diagnosis and treatment. significantly increases morbidity and mortality. Material and Method: Thirty-seven patients with esophageal perforation were surgically treated at our institutions between January 1990 and December 2006. We retrospectively reviewed the results of surgical treatment for esophageal perforation to understand the risk factors affecting survival inpatients. Result: Patients ranged in age from 21 to 87 years, with an average age of $52.7{\pm}16.98$ years. Thirty-one of the patients were men and six were women. There were 23 patients (62%) with spontaneous perforations, 10 patients (27%) with a traumatic perforation, and 4 patients (11%) with an iatrogenic perforation. The site of esophageal perforation was the cervical esophagus in 5 patients, the thoracic esophagus in 31 patients, and the abdominal esophagus in one patient. Twenty-nine patients underwent primary closure of the perforation and five patients had T-tube drainage. Exclusion-diversion procedures were performed in two patients and an esophagectomy was performed in one patient. There were six cases of mortality (16.22%) and 25 cases of postoperative complications in 15 patients (40.5%). Patients that were treated later than 24 hours after detection of the perforation showed a statistically significant high morbidity and mortality rate (p<0.05). Conclusion: The most important risk factor of esophageal perforation was the time interval between detection of the perforation and the initiation of treatment. A prompt diagnosis and effective treatment are necessary to decrease morbidity and mortality.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.90-98
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• 2016

High-rise buildings construction project have various risk factors. Major risk factors are negative results such as time delay and increase of costs. Therefore, this study was analyzed risk factors in construction stages of high-rise buildings using by PROMETHEE technique. For this, this research were identified risk factors through experts Focus Group Interview(FGI). And, PROMETHEE was used to setup evaluation standard for analysis of high-rise building construction risks. Next, the standard of evaluation index calculation was composed by using the definition level in PDRI. Preference function and evaluation index were identified through questionnaires. Through these processes, this study has calculated the importance of high-rise building construction risks using by PROMETHEE technique. As a result, high degree risk factors were as following. These are 'Operation plan of material lifting', 'Outrigger & Belt Truss Construction', 'Foundation work plan of high-rise building' and 'Considering a Structure concept of high-rise building'.

• Development and Reproduction
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• v.9 no.1
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• pp.43-48
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• 2005

Bone marrow stromal cells, a constituent of the niche for hematopoietic stem cells in bone marrow, provide various factors involved in the fate decision of the hematopoietic stem and progenitor cells. Radiation, a widely used anti-cancer therapy, provokes side effects including the damage of the blood cells. Therefore, it is necessary to recover the blood cells shortly after radiation via promoting the differentiation of hematopoietic cells. In this study, we screened genes modulated by radiation in human bone marrow stromal cells in order to understand the mechanism involved in hematopoiesis after radiation. We performed differential display method by using polymerase chain reaction(PCR) and agarose gel electrophoresis. We found plasminogen activator inhibitor-1(PAI-1) was consistently induced by radiation. The significance of the PAI-1 gene modulation is to be determined.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.161-169
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• 2011

The objective of this study was to evaluate the efficiency of a modified filtration system treating non-point source (NPS) pollutants. The developed Best Management Practice (BMP) technology was designed based on the geographical and climatic characteristics of the site. A lab-scale test experiment was conducted using three different hydraulic loading rates representing the first flush flow, average flow and overflow conditions during a rainfall event. Water quality analysis was performed on the water samples taken at the inflow, outflow and infiltration during the test experiment of the lab-scale BMP. Also, the water and mass balance at different hydraulic loading rates was determined. Results from the lab-scale test experiment showed that the lab-scale BMP had a high removal efficiency of 80-90% for all NPS pollutants. The overflow test condition obtained the lowest removal efficiency among the hydraulic loading rates because it gave less opportunity for the pollutants to be filtered and retained inside system. The infiltration ratio was approximately 1 % of the inflow and outflow. Increasing the infiltration ratio requires technical approach of soil amendment where the BMP is installed.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1432-1436
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• 2007

도시화로 인한 유출량의 증가 및 도달시간의 단축은 도시재해의 한 원인이 되고 있다. 이를 막기 위하여 도시 배수유역내에 저류지를 설치하여 첨두도달시간을 지연시키고 방류량은 하수관거의 통수능 이하로 조절하는 방안을 활용하고 있다. 저류지를 설계 운영함에 있어서 사용되는 수문모형은 일반적으로 계획모형, 설계모형 및 운영모형으로 분류되고 있다. 계획모형과 유사한 형태의 단순화된 설계모형이 있기 때문에 계획모형과 설계모형을 엄밀히 구별하기는 어려우나 일반적으로 저류지 용량 결정시 배수구역에 대한 홍수추적을 실시하여 구하는 경우를 설계모형으로 보고 있다. 본 연구에서는 재해영향평가서 22개소의 기 설계된 저류지를 분석대상으로 하여 여러 가지 저류지 계획모형과 설계모의모형(WinDETPOND 모형, BASINOPT 모형)의 적합성을 검토하고 분석대상 저류지와 비교분석을 실시하였다. 저류지 계획모형의 분석에서 on-line 저류지의 경우는 사다리꼴 형태 설계수문곡선을 채택하고 있는 이종태 등 모형의 결과가 대상 저류지의 실저류량과 가장 유사함을 보였고, off-line 저류지의 경우는 삼각형 형태 설계수문곡선을 채택하고 있는 Abt & Grigg 모형의 결과가 비교적 양호한 결과를 보이는 것으로 나타났다. on-line 실저류지 3개소의 저류지 계획모형과 설계모의모형의 결과를 비교분석결과 도시화 인자 ${\alpha}$의 연관성은 뚜렷이 나타나지는 않았지만, WinDETPOND 모형의 저류량은 BASINOPT 모형에 비해 실저류지와 유사한 결과를 나타내었다.