• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.2
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• pp.80-85
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• 2014

Side jet thruster using nozzle closure separation device provides a solid rocket with a trajectory shift function. Side jet thruster consists of low combustion temperature propellant, neutral type propellant grain and nozzle closure separation device. If a trajectory shift is required, side jet thrust is generated on the rocket by separating some nozzle closures located in the opposite direction to thrust. After completing trajectory shift, the other nozzle closures located in the thrust direction are separated to cease side jet thrust. The operation process is verified through ground static test. The result in this study can be applied to changing rocket trajectory by controlling side jet thrust through nozzle closure separation.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1167-1174
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• 1997

We retrospectively reviewed a series of 20 patients treated with delayed sternal closure during a 5-year period from 1991 to 1996. Of the 2675 patients with cardiovascular su gery 20 underwent this procedure. Male and female ratio was 11:9, mean age was 6.4 months(range 7 days to 5 years). The indications included unstable hemodynamic profiles after open heart surgery due to myocardial edema and poor lung compliance(15), necessity of mechanical ventricular assist device due to weaning failure(3), and hypoxia after PAB(2). Sternum was closed at a mean interval of 102(range 4 to 213) hours after operation. During delayed sternal closure, central venous pressure was elevated(p<0.05). Mediastinitis and other wound problems did not occur. Sepsis developed in 2 patients and microorganism was confirmed in one of the two patients. Five patients died(mortality 25%). And two of 15 discharged patients died during follow-up period. Cumulative survival rate was 65.0% at 12 months and also 65.0% at 24 months.(Standard error was 10.7%) Delayed sternal closure Is considered to be a good method to decompress the hemodynamically compromised heart. Without that, it is not f asible to come off bypass or to decompress the heart. Of course. careful selection of the indication is imperative.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.517-522
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• 2002

Background: Congenital heart surgery may lead to myocardial swelling and hemodynamic instability. Delayed sternal closure may be beneficial in this setting. The purpose of this study was to assess mortality and mediastinal infection rate associated with delayed sternal closure after congenital heart surgery and to evaluate the risk factors which affect mortality and mediastinal infection rate. Material and Method: We retrospectively reviewed 40 patients who underwent delayed sternal closure after repair of congenital heart disease at Yonsei Cardiovascular Hospital, from January 1994 to May 2001. In these patients, we assessed the mortality and mediastinal infection rate, and evaluated their risk factors including operation time, bypass time, aortic cross clamp time, duration to sternal closure and postoperative artificial ventilation time. Mediastinal infection was defined to have positive culture in mediastinum. Result: Hemodynamic instability was the most common indication for delayed sternal closure(n=36) and other indications included postoperative bleeding(n=2) and conduit compression(n=2). The median age at operation was $14.4{\pm}33.4$months old(range, 2days-12years). The patients with postoperative bleeding and conduit compression were much older than the others. The sternum was left open for $4.5{\pm}3.4$ days(range, 1-20days). Overall mortality was 25%(10/40) and mediastinal infection occured in 24.3%(9/37) (3 patients were excluded in mediastinal infection for early death). In risk factor analyses, only aortic cross clamp time had statistical significance for mortality in univariate analyses. However, multivariate analyses revealed that there were no significant predictors for risk of mortality and mediastinal infection. Conclusion: Delayed sternal closure after repair of congenital cardiac disease had relatively high mortality and mediastinal infection rate. But, in patients with hemodynamic instability, postoperative bleeding and conduit compression after repair of congenital cardiac disease, delayed sternal closure may be an effective life saving method.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.329-332
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• 2011

Purpose: In developed countries, vesicovaginal fistula occur from various pelvic operations including total hysterectomy, leading to urinary leakage and incontinence. Although various methods have been proposed for adequate tissue coverage in fistula repair, the surgical treatment of is not simple and still controversial. We report a case of neobladder-vaginal fistula repair using modified Martius fat pad flap. Methods: A 62-year-old female patient underwent radical cystectomy with total abdominal hysterectomy and neobladder formation due to invasive bladder tumor 5 years ago. For 3 years following the operation, urine leakage was observed. Exploration demonstrated neobladder-vaginal fistula and primary repair including fistulectomy and direct closure was performed. Urinary incontinence relapsed 2 years after primary repair, and after demonstrating the recurrence of fistula on urography, repair of recurrent fistula was performed. After dissection of vagina and neobladder and closure of fistula by urologic surgeon, fibroadipose flap was elevated, rotated and advanced through the tunnel at vaginal sidewall, and interpositioned to the fistula site between neobladder and vagina. Results: There was no acute complication after the surgery and urethral catheter was extracted on the 8th day after the operation. During six month follow-up period after the operation, there is no clinical evidence of fistula recurrence. Conclusion: From our clinical experience and literature review, we think Martius fat pad flap is a useful technique in management of neobladder-vaginal fistula, for it provides enough vascularity, major epithelization surface and better lymphatic drainage, and also prevents overlapping of vesical, vaginal suture lines at the same time.

• Journal of Chest Surgery
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• v.48 no.1
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• pp.25-32
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• 2015

Background: We evaluated operative outcomes after third or more cardiac operations for valvular heart disease, and analyzed whether pericardial coverage with artificial membrane is helpful for subsequent reoperation. Methods: From 2000 to 2012, 149 patients (male : female=70 : 79; mean age at operation, $57.0{\pm}11.3$ years) underwent their third to fifth operations for valvular heart disease. Early results were compared between patients who underwent their third operation (n=114) and those who underwent fourth or fifth operation (n=35). Outcomes were also compared between 71 patients who had their pericardium open during the previous operation and 27 patients who had artificial membrane coverage. Results: Intraoperative adverse events occurred in 22 patients (14.8%). Right atrium (n=6) and innominate vein (n=5) were most frequently injured. In-hospital mortality rate was 9.4%. Total cardiopulmonary bypass time ($225{\pm}77$ minutes vs. $287{\pm}134$ minutes, p=0.012) and the time required to prepare aortic cross clamp ($209{\pm}57$ minutes vs. $259{\pm}68$ minutes, p<0.001) increased as reoperations were repeated. However, intraoperative event rate (13.2% vs. 20.0%), in-hospital mortality (9.6% vs. 8.6%) and postoperative complications were not statistically different according to the number of previous operations. Pericardial closure using artificial membrane at previous operation was not beneficial in reducing intraoperative events (25.9% vs. 18.3%) and shortening operation time preparing aortic cross clamp ($248{\pm}64$ minutes vs. $225{\pm}59$ minutes) as compared to no-closure. Conclusion: Clinical outcomes of the third or more operations for valvular heart disease were acceptable in terms of intraoperative adverse events and in-hospital mortality rates. There were no differences in the incidence of intraoperative adverse events, early mortality and postoperative complications between third cardiac operation and fourth or more.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.119-123
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• 1999

Background: From January 1989 to December 1996, we analyzed 22 cases of ventricular septal defect associated(VSD) with aortic valvular prolapse. Material and Method: The mean age of the patients was 7 years with a range of 6 months to 22 years . Thirteen patients were male and 9 were female. The types of VSD were Kirklin type I in 13 , Kirklin type II in 8 and Kirklin type I+II in one. Result: The preoperative echocardiographic findings were aortic valvular prolapse in 10 patients, aortic valvular prolapse associated with aortic regurgitation in 6, and only aortic regurgitation in 2. Aortic valvular prolapse were found in operation field in 4 that was not be in preoperative echcardiography. Preoperative mean Qp/Qs, systolic PAP, systolic RVP were 1.48${\pm}$0.42, 27.9${\pm}$9.87, 32.9${\pm}$10.87 mmHg, respectively. Twenty patients underwent patch closure of VSD, and two patients with moderate aortic regurgitation and prolapsed of the aortic valve underwent patch closure of VSD and aortic valvuloplasty. Short and long term echocardiographic follow-up in 8 patients who had preoperative aortic regurgitation were found to have improved or not aggravated by performing VSD patch closure only and patch closure with valvuloplasty in 2. Twelve patients who had only preoperative aortic valvular prolapse had no change in prolapsed valve in postoperative echocardiography. Conclusion: Early closure of VSD with patch is necessary in VSD with aortic valvular prolapse even in associated with mild regurgitation. But in moderate regurgitation, VSD closure with valvuloplasty is recommended.

• Journal of Chest Surgery
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• v.40 no.12
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• pp.837-842
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• 2007

Background: Closure of the ductus arteriosus is often delayed in premature infants, which creates a hemodynamically significant left to right shunt that exerts an adverse effect on the normal development and growth of these babies. We reviewed out experience on surgical closure of patent ductus arteriosus via axillary minithoracotomy in premature infants. Material and Method: From April 2002 to October 2006, 20 premature infants whose gestation was under 37 weeks underwent surgical closure of patent ductus arteriosus as a result of complications or contra-indications for the use of indomethacin. Their mean gestational age was 28.8+3.4 weeks, ranging from 25+3 to 34+6 weeks, and the average age at operation was $15.6{\pm}6.3$ days. The mean body weight at operation was $1,174{\pm}416\;g$, ranging from 680 to 2,100g; 16 infants were under 1,500 and 9 infants were under 1,000 g. The procedures were performed in the newborn intensive care unit via $2{\sim}3\;cm$ long axillary minithoracotomy with the infant in the lateral position with left arm abduction. The mean size of the patent ductus arteriosus was $3.8{\pm}0.3\;mm$. For the most part, the ductus was closed with clips; 2 infants in whom the ductus was ruptured while dissection was being performed underwent ductal division. Result: Ten of twelve infants who had been ventilator dependent preoperatively could be successfully weaned from the ventilator at a mean duration of 9.7 days after the operation. There was no procedure-related complication or death. Two infants eventually died of the conditions not related to the operation; one from sepsis at postoperative 131 days and the other from pneumonia at postoperative 41 days, respectively. Conclusion: Surgical closure of the patent ductus arteriosus improved the hemodynamic instability and so promoted the successful growth and normal development of premature infants. Considering the low surgical risk along with the reduced invasiveness, early and aggressive surgical intervention is highly recommended.

• Journal of Chest Surgery
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• v.24 no.2
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• pp.135-142
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• 1991

From January 1980 to December 1989, thirteen patients underwent operation for ventricular septal defect associated with aortic insufficiency in Kyungpook national university hospital. Ten male and three female patients ranged in age from 3 years to 25 years, with an average age of 11.5 years. Aortic cusp prolapse was found in eight cases[61.5%]. The aortic regurgitation was classified by Sellers` method with grade I in 2 cases, grade II in 9 cases, and grade III in 2 cases. Direct suture or patch repair of ventricular septal defect was performed through the right ventricle. Eight cases were treated only by closure of VSD, 3 cases by plication, but two of the letter were reoperated due to the persistent of aortic regurgitation and fungal endocarditis respectively. Aortic valve replacement were performed in 2 cases at the first operation. There was only one late death[7.7%], which was caused by postoperative fungal endocarditis. Follow-up for twelve patients except one death were followed up for 3 months to six years after operation. Residual aortic regurgitation was noted in six cases[46.2%], but the postoperative course of them were uneventful.

• Korean Journal of Mathematics
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• v.20 no.4
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• pp.371-379
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• 2012

Let D be an integral domain, $\bar{D}$ be the integral closure of D, * be a star operation of finite character on D, $*_w$ be the so-called $*_w$-operation on D induced by *, X be an indeterminate over D, $N_*=\{f{\in}D[X]{\mid}c(f)^*=D\}$, and $Kr(D,*)=\{0\}{\cup}\{\frac{f}{g}{\mid}0{\neq}f,\;g{\in}D[X]$ and there is an $0{\neq}h{\in}D[X]$ such that $(c(f)c(h))^*{\subseteq}(c(g)c(h))^*$}. In this paper, we show that D is a *-quasi-Pr$\ddot{u}$fer domain if and only if $\bar{D}[X]_{N_*}=Kr(D,*_w)$. As a corollary, we recover Fontana-Jara-Santos's result that D is a Pr$\ddot{u}$fer *-multiplication domain if and only if $D[X]_{N_*} = Kr(D,*_w)$.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.233-239
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• 1979

Ventricular septal defect associated with patent ductus arteriosus is well known cardiac anomaly that can be treated successfully by operation. This anomaly is found at low frequency. Seven cases of the combined malformation were operated on during the period from 1959 to 1978 in the Department of Thoracic Surgery, Seoul National University Hospital. Right heart catheterization and retrograde aortogram can diagnose the disease correctly. Staged operation in one case and one-stage operation in 5 patients were done. In all cases of the open heart surgery the closure of the ductus was done by transpulmonary suture of the PDA opening. Among 6 patients of the open heart surgery 2 operative death [33.3%] and one late death [total 50%] were noted. Four type II and one type I and one Type IV VSDs were found. In one case the anomaly was accompanied with aortic insufficiency by herniation of the right coronary cusp through Type I VSD.