• 한국한의학연구원논문집
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• 제17권3호
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• pp.105-114
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• 2011

Objectives : The transient inflammation has been demonstrated to alter visceral motor response (VMR) and acute mucosal inflammation may precede the manifestation of visceral hyperalgesia in animal models. The purpose of our study is to compare effects of the different frequencies applied electroacupuncture (EA) on acupoints in acute colitis induced by trinitrobenzenesulphonic acid (TNBS). Methods : In Male Sprague-Dawley rats, weighing 250~400g, a single colorectal administration of TNBS (5mg/kg) was made and electrode for electromyography (EMG) recording were stitched into the external oblique musculature. EA of either ST25 or ST36 were applied and stimulation parameter was modulated as follows: 2, 10, or 100 Hz with intensity of 2 mA and 1 ms pulse duration for 30 min. The balloon was inserted intra-anally and VMR to colorectal distension (CRD) was quantified with an EMG recording system. Results : The VMR increased significantly 3 days after TNBS intra-rectal colonic injection in rats. Both 2 Hz and 10 Hz EA on ST36 suppressed VMR to CRD in the acute colitis model but not 100 Hz. Only 10 Hz EA on ST25 suppressed VMR to CRD in the acute colitis. Conclusions : These data show that 10 Hz EA potently inhibits hypersensitivity of colorectum after TNBS induced colitis.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2011-2018
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• 2024

Since RF breakdown is one of the primary limitations to improving the performances of RF accelerators, extensive efforts have been dedicated to locating the breakdowns. However, most existing methods rely on specialized techniques, resulting in high financial burdens. Although the method based on transient response of transmission line (TL) is suitable for facilities with sporadic recoverable breakdowns, practical operations are susceptible to notable errors. This study revisits the fundamental theories of lossless TL and investigates the wave process to understand the characteristics of the reversed pulse induced by the breakdowns. By utilizing steadystate response of the TL and employing phasor method, we derive analytical formulas to determine the exact location of breakdowns within the faulty cell for constant-gradient TW accelerator. Furthermore, the derived formulas demonstrate their independence from RF phase, thereby distinguishing them from traditional phasebased methods. Additionally, experimental validations are conducted at the HUST injector, and the results confirm the consistency of the analysis. Thus, the proposed method represents a promising improvement over the TL-based approaches and serves as a valuable complement to current techniques. Importantly, this method demonstrates particular advantages for constructed TW accelerators seeking to achieve a balance among high performance, low costs, and compact layouts.

• 조명전기설비학회논문지
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• 제20권4호
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• pp.21-28
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• 2006

본 논문에서는 Ballard사의 1.2[kW]급 연료전지와 연료전지의 저전압($28{\sim}43[VDC]$)을 승압(380([VDC])시키기 위한 풀-브리지 직류-직류 컨버터, 그리고 승압된 직류 링크전압을 교류 전압(220[VAC]), 60[Hz]으로 변환하기 위한 단상 풀-브리지 인버터로 구성된 연료전지 발전용 전력변환시스템 중 풀-브리지 고주파 절연형 영전압 영전류 스위칭 위상 천이 펄스폭 변조 직류-직류 컨버터를 제안하였다. 제안한 풀-브리지 고주파 절연형 영전압 영전류 스위칭 위상 천이 펄스폭 변조 직류-직류는 프리휠링 다이오드를 포함한 탭부 인덕터 필터를 이용하여 순환 전류를 저감시켰으며, 스위치 및 변압기의 턴-온, 턴-오프시에 오버슈트 전압이나 과도현상이 발생하지 않는다. 그리고 넓은 출력 전압 조정에도 효율을 $93{\sim}97[%]$정도 얻을 수 있으며, 출력 부하전류의 변화에 대해 거의 일정한 출력 전압 특성을 가졌다.

• Journal of Chest Surgery
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• 제17권4호
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• pp.593-606
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• 1984

With the ligation of patent ductus arteriosus by Gross in 1938, surgeons first entered the field of congenital heart disease. Interruption of a ductus is one of the most satisfactory and curative operations in the field of surgery for congenital heart disease. 27 cases of isolated patent ductus arteriosus were operated from Jan. 1978 to July 1984 at the Department of Thoracic & Cardiovascular Surgery in Kyung-Hee University Hospital. Retrospective clinical analysis of these patients were: 1. Sex ratio, female: male, was 2:1. 2. Mean age at operation was 9.85\ulcorner.58 years. The youngest patient was a 23 month-old girl and the oldest one was a 24 year-old male. 3. More than half of the patients had less than 50 percentile of growth retardation. 4. Chief complaints of the patients were frequent URI [52%], dyspnea on exertion [33%], generalized weakness [22%], palpitation [7%], but 7 patients [26%] had no subjective symptoms. 5. Continuous machinery murmur could be heard at the 2nd or 3rd intercostal space on the left sternal border in 22 patients [81%]. The other S patients made systolic murmur with accentuation of the second heart sound and those were associated with pulmonary hypertension. 6. Radiologic findings of Chest P-A were cardiac enlargement in 15 patients [55%], enlargement of pulmonary conus and/or increasing density of pulmonary vascularity in 20 patients [74%]. 7. Electrocardiographic findings of the patients were within normal limit in 13 patients [48%], LVH in 4 patients [15%], biventricular hypertrophy in 3 patients [11%]. 8; echocardiogram was obtained from 11 patients. Ductus was directly visualized in 7 patients. Left atrial enlargement is the secondary change of left to right shunt, 10 patients had LA/Ao ratio more than 1.2. 9. Cardiac catheterization performed in 25 patients. The mean value of the results were:SO2[PA-RV]= 14.72\ulcorner6.01%, Qp/Qs=2.22\ulcorner.80, peak systolic pulmonary arterial pressure=48.28\ulcorner1.60 mmHg. 10. 26 patients were operated through the left posterolateral thoracotomy: closure of ductus by double ligation in 14 cases, triple ligation in 5 cases, and division with suture in 8 cases. One patient suffer from aneurysmal rupture of main pulmonary artery, endocarditis, hemopericardium was treated with cardiopulmonary bypass via median sternotomy and closure of ductus through the ruptured main pulmonary artery. 11.There was no death associated with the operation, but 3 cases were experienced with intraoperative rupture around the ductus resulting in massive bleeding. The other complications were transient hoarseness in one patient, atelectasis in left lower lobe in 3 patients, and postoperative systemic hypertension in 4 patients with unknown etiology. 12. Pulse pressure was reduced, 11.47+5.92 mmHg, postoperatively, as compare to preoperative status. 13. Intraoperative wedge lung biopsy from lingular segment for the evaluation of the pulmonary vascular disease was taken in S patients with severe pulmonary hypertension. The result was Heath-Edward grade I in one case, grade II in two cases, and grade III in two cases.

• Tuberculosis and Respiratory Diseases
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• 제81권4호
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• pp.319-329
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• 2018

Background: Bronchoalveolar lavage (BAL) is a necessary procedure for diagnosis of various lung diseases. High-flow nasal cannula (HFNC) oxygen delivery was recently introduced. This study aimed to investigate the safety and effectiveness of HFNC oxygen supply during BAL procedure in patients with acute respiratory failure (ARF). Methods: Patients who underwent BAL while using HFNC at a partial pressure of oxygen in arterial blood/fraction of inspired oxygen ($PaO_2/FiO_2$; PF) ratio of 300 or below among patients who had been admitted from March 2013 to May 2017 were retrospectively investigated. Results: Thirty-three BAL procedures were confirmed. Their baseline PF ratio was $166.1{\pm}46.7$. $FiO_2$ values before, during, and after BAL were $0.45{\pm}0.12$, $0.74{\pm}0.19$, and $0.57{\pm}0.14$, respectively. Flow (L/min) values before, during, and after BAL were $26.5{\pm}20.3$, $49.0{\pm}7.2$, and $40.8{\pm}14.2$, respectively. Both $FiO_2$ and flow during and after the procedure were significantly different from those before the procedure (both p<0.001). Oxygen saturation levels before, during, and after BAL measured by pulse oximeter were $94.8{\pm}2.9$, $94.6{\pm}3.5$, and $95.2{\pm}2.8%$, respectively. There were no significant differences in oxygen saturation among the three groups. Complications of BAL procedure included transient hypoxemia, hypotension, and fever. However, there was no endotracheal intubation within 24 hours. Baseline PF ratio in "without HFNC" group was significantly higher than that in "with HFNC" group. There were no differences in complications between the two groups. Conclusion: The use of HFNC during BAL procedure in ARF patients was effective and safe. However, there were no significant differences in oxygen saturation level and complications comparing "without HFNC" group in mild ARF. More studies are needed for moderate to severe ARF patients.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제11권1호
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• pp.21-27
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• 2008

목 적: 한국 소아청소년에서 시행되는 의식하 진정내시경 시행 실태와 부작용, 그리고 새로운 약제 등의 사용 여부 등을 다기관 연구를 통해 파악하여 적절한 지침을 세우는데 도움을 주고자 하였다. 방 법: 대한소아소화기영양학회 회원 소속 병원 중 2차 병원 이상의 병원을 대상으로 2006년 6월부터 2006년 7월까지 한 달의 기간 동안 시행된 내시경 검사를 대상으로 하였으며, 16개의 문항으로 설문지를 만들어 배포 후 수거된 결과를 조사 분석하였다. 결 과: 전체 내시경 시술 횟수 465예 중 의식하 진정 내시경은 89.0% (414예), 전신 마취하에 시술한 예는 0.9% (4예)였으며, 의식하 진정내시경의 비율은 상부소화관의 경우 89.1% (362예), 하부소화관의 경우는 88.1%(52예)였다. 의사 한 명 당 한달 평균 16.0건의 내시경을 시술하고 있었으며, 내시경을 시행하는 의사 수는 병원당 평균 1.16명, 보조자는 평균 2.58명이었다. 또한 마취과 의사의 도움을 받는 경우는 3개(12%) 병원이었다. 사용한 약물은 전체 의식하 진정내시경 414예 중 미다졸람(midazolam)만 사용한 경우가 전체 84.5% (350예), 프로포폴(propofol)을 사용한 경우는 상부소화관 내시경을 시행한 2예(0.5%)였고, 2가지 이상의 복합제재를 사용한 경우는 하부소화관검사의 경우 44예(84.6%), 역행성담관조영술(ERCP)의 경우가 2예(100%)였다. 진정내시경 시행 중 사용한 모니터링은 심전도 감시와 함께 맥박산소측정기를 사용한 경우가 91.4% (320예), 자동혈압측정기를 같이 사용한 경우 5.1% (18예)였다. 부작용으로는 일시적 산소포화도의 저하로 산소를 투여한 경우로 4.6% (16예)였다. 또한 길항제로 flumazenil을 투여한 경우는 모든 환자에서 투여한다고 답한 경우를 제외하면 2.71% (9예)였다. 진정내시경 시행 여부의 결정은 환자 혹은 환자의 보호자와 상의하여 결정하는 경우가 84% (21개 병원)였다. 의사가 느끼는 만족도는 68%에서 만족하는 것으로 나타났으며, 의사가 느끼는 환자 혹은 환자 보호자의 만족도는 만족이 84% (21개 병원)였다. 결 론: 우리나라 소아의 의식하 진정내시경 시 사용한 약물은 대부분 미다졸람 단독 투여만으로 시행하며, 하부소화관 검사 시에는 복합 약물을 투여한 경우가 많았다. 또한 환자와 의사 대부분 만족하는 것으로 나타났으며, 부작용은 거의 나타나지 않았다.