• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.141-144
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• 2000

Highly open porous polymer matrices are required for high density cell seeding, efficient nutrient, and oxygen supply to the cells cultured in the three dimensional matrices. However, there are severe problems of mass transfer limitations within the cell/scaffolds culture system. Thus we hypothesize that continuos-flow culture conditioning of cells with the scaffolds may improve the cell viability and the differentiated function. In this study, we fabricated porous PLGA scaffolds by using gas-foaming/salt-leaching method as previous described. Viscous PLGA gel paste contains ammonium bicarbonate particulates, acting as a gas-foaming agent as well as a salt-leaching porogen, were cast into Teflon mold and dried. Ammonium bicarbonate salt upon contact to an acidic aqueous solution evloves gaseous ammonia and carbon dioxide by itself. And we conjugated galactose moiety [AGA; $N-(aminobuty1)-O-{\beta}-D-galactopyranosyl-(1{\rightarrow}4)-D-glucoamide]$ to the terminal end group of a PLGA to increase the cell adhesion and matain the differentiated function of hepatocytes. Cell-seeded scaffolds were secured in a flow bioreactor chamber and exposed to continuous flow at 5 ml/min. As a result of our study, the high yield of hepatocytes attachment was accomplished by increasing the concentration of PLGA-AGA conjugate in polymer scaffolds and cells in the scaffolds under continuos flow condition maintained a high level of viability and albumin secretion rate of cultured hepatocytes showed a higher level that of control groups.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.217-224
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• 2002

The purpose of this study was to evaluate the influence of saliva contamination on the resin bonding of the etched metal retainers. The test samples were made of Verabond, and divided into 3 groups. Retainers in group1 had normally etched metal surfaces. Retainers in group2 had normally etched metal surfaces which were saliva-contaminated for 30 seconds and cleaned with streaming, luke-warm for 1 minute and dried thoroughly. Retainers in group3 had normally etched metal surfaces which were saliva- contaminated for 30 seconds and dried thoroughly without water-cleansing. Each 3 group specimen was watched on SEM. A resin core, 5mm in diameter and 6mm in length, was made of Panavia using Teflon mold on the each specimen. These 3 groups were tested to evaluate shear bond strength, using universal testing machine. The results were as follows : 1. The shear bond strength showed no significant difference between group1 and group2. 2. The shear bond strength showed significant difference between group1 and group3. 3. The shear bond strength significant difference between group2 and group3. 4. Scanning electron microscope photographs of group1 and group2 showed no signs of contamination but of group3 showed somewhat contaminated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.1
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• pp.3-8
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• 2011

This paper introduces a robot eye module, of which two degree-of-freedom motions, i.e. panning and tilting, are driven by a pair of wires. The main feature of the module is that each wire can generate push-pull motion without buckling. It is thanks to a Teflon tube which guides the path of the moving wire. End points of the tube and wire have pivot elements so that a smooth push-pull motion is produced even when the end point of wire is moved by eye rotation. This mechanism helps the eye module to be very compact. In this paper, the structure of the robot eye module is introduced in detail, and the required motor angles for a certain direction of eye line are investigated analytically and experimentally.

• Journal of Chest Surgery
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• v.17 no.1
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• pp.150-156
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• 1984

Paraesophageal hiatus hernia represents a rare hiatal hernia that are treated surgically. The completely asymptomatic paraesophageal hernia often does not reach the clinician or surgeon. But the presence of a symptomatic paraesophageal hernia is sufficient indication for surgery. The paraesophageal hernia may be approached either transthoracically or transabdominally. The general technique is essentially the same, whichever route is used. From either transthoracic or transabdominal approach, following reduction of the viscus and elimination of the sac, the diaphragmatic opening is then closed with interrupted heavy dacron or silk sutures in paraesophageal hiatus hernia. But if the phrenoesophageal membrane often is destroyed when the esophagogastric junction and the distal esophagus have been mobilized, it becomes important to fix the esophagogastric junction below the diaphragm, so that it does not slide through the hiatus and produce a sliding-type hiatus hernia in future. We have experienced one case of paraesophageal hiatus hernia which was accompanied with severe anemia in child. We preferred to approach through left thoracotomy incision and then pushed down the stomach into the abdominal cavity with complete excision of the hernial sac. We employed Belsey Mark V procedure using of Teflon felt pledgets with the mattress sutures against development of sliding-type hiatus hernia in postoperative period. postoperative course has been uneventful and good for about 3 months to this time.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.259-265
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• 1982

We have designed a new type of bubble oxygenator (KOREA-KIM VENOTHERM OXYGENATOR) made of PVC sheet and deforming mesh incorporated in the heat exchanger, and evaluated in experimental animal for the analysis of it`s efficiency. The Oxygenator has low priming volume with high flow rate up to 6 L/rain, and efficiency of heat exchanger was excellent as 1-$1.5^{\circ}C.$ using total cardiopulmonary bypass method under moderate to deep hypothermia. Average priming volume of 1317 ml with 30% hemodilution method was perfused with an average of 1.1-3.0 L/min.$M^2$of arterial blood and pure oxygen at a rate of 2-3.4 L/min for 49.6 minutes continuously in average. During total cardiopulmonary bypass, average $PaO_2$ was $159.8{\pm}60$mmHg, $PaCO_2$ $41.0{\pm}3$mmHg respectively under $SaO_2$ over 96% with systolic arterial pressure of 70 mmHg and CVP of 5-10 cm$H_2O$. Plasma free Hemoglobin was $7.0{\pm}4$ mg/dl with 25% drop of hemoglobin and hematocrit at the end of cardiopulmonary bypass. This KKV Oxygenator was observed to have excellent capabillty of oxygen and carbon dioxide gas transfer with small amount of blood trauma, and the efficiency of heat exchanger was satisfactory during cooling and rewarming of the bubbled blood. Disadvantages have included the somewhat poor deforming effect due to loose PVC fiber mesh, the extracompact character of Teflon filters, and the rough inner surface of the heat exchanger copper pipes.

• Journal of Chest Surgery
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• v.12 no.1
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• pp.50-55
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• 1979

The development of aortic insufficiency radically alters the physical findings which are generally associated with ventricular septal defect that was not hemodynamically significant, and the combination of the two lesions produces a typical clinical picture, that may be serious and life-threatening when it is left untreated. Therefore, the selection of patients, type and timing of surgical treatment is considered to be important. Among 114 cases of ventricular septal defect treated surgically utilizing cardiopulmonary bypass in the Department of Thoracic Surgery, Seoul National University Hospital, 7 cases were associated with aortic insufficiency. 1. Five cases were male, and 2 cases were female. Ages were from 4 years to 24 years, and mean age was 11.9 years. 2. In all cases, ventricular septal defect was closed with Teflon patch. In a case, a aortic valvuloplasty and in another, a aortic valve replacement with Hancock valve 23 mm., 5 months after the closure of ventricular septal defect were done. 3. Four cases were type I ventricular septal defect by Kirklin`s classification, 3 cases were type II ventricular septal defect, and diameters of ventricular septal defect were from 3.5 cm. to 0.7 cm. A PDA. was combined to a type I ventricular septal defect. 4. In 5 cases, herniation of the aortic cusp through the ventricular septal defect and in a case, annulus dilatation on the aortic valve was noted. 5. Two cases with type I ventricular septal defect and severe pulmonary hypertension expired. A re-opened case with type II ventricular septal defect expired. 6. Four cases were alive, and all of them show decrease of pulse pressure and aortic insufficiency.

• Journal of Chest Surgery
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• v.8 no.2
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• pp.81-88
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• 1975

Up to October 31, 1975, 34 cases of atrial septal defect, secundum type, operated in this department, were presented. This is 23.2% of all congenital heart diseases, operated utilizing cardiopulmonary bypass, in this department during this period [34 out of 146]. Out of 34 cases, 32 cases are pure ostium secundum type and one case is sinus venosus and another one is ostium secundum type with partial anomalous pulmonary venous drainage. Six cases of endocardial cushion defect and 3 cases of trilogy of Fallot are excluded in this report. All 34 cases are repaired under direct vision utilizing extracorporeal circulation. Among 34 cases of atrial septal defect, 16 cases are male, and 18 cases are female. Their ages range between 3 to 48 years, but over 59% of the cases are below the ages of 20 years. Thirty-two cases are repaired by direct sutures while 2 cases are repaired with Teflon patches. The average perfusion time is 30 minutes; the shortest 12 and the longest 81 minutes. The number of the defect is single in 31 cases, double in 2 cases, triple in one case. But the associated defect except the main defect are so small as can be closed by simple direct suture. The size of the defect is average $12cm^2$; the smallest 0.7 and the largest $25cm^2$. The surgical mortality is 2 cases [5.6%] and other cases are found to be excellent in the follow up studies.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.779-781
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• 2010

After preliminary tests indicated an increased number of heterotrophic bacteria, we investigated possible sources of contamination in a neonatal intensive care unit (NICU) water distribution system. Scanning electron microscopic examination of flexible metallic hoses associated with the system revealed the presence of a biofilm; partial 16S rDNA sequencing revealed that the biofilm contained Blastomonas natatoria. Purgation of the water system three times a day, reinforced faucet cleaning, decreasing the cold water temperature to $12^{\circ}C$, and six repeated chlorinations at concentrations as high as 2 mg/l were not sufficient to eradicate the bacterial contamination. Replacing all of the rubber-interior flexible metallic hoses with teflon-lined hoses, followed by heating the water to $70^{\circ}C$, successfully controlled the bacteria.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.342-347
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• 1978

A 8 year old male was admitted to the Department of Thoracic Surgery, Korea University Hospital on June 22, 1978. The chief complaints were cyanosis and exertional dyspnea since at birth. EKG shows BVH and dextrocardia, phonocardiogram revealed the accentuation of second heart sound in aortic area. Echocardiogram from the left ventricle to the base of the heart, there is a discontinuity between the ventricular septum and the anterior aortic margin with a large aortic root & aortic overriding. His cardiac catheterization data and cardiac angiogram shows situs inversus totalis, dextrocardia, right aortic arch, large ventricular septal defect etc., and finally diagnosed Truncus Arteriosus. Edwards type IV with retrograde aortogram and selective bronchial angiogram. This is the first operative case reported as Rastelli operation for Truncus Arteriosus type IV in the literatures in Korea. Authors have experienced I case of Truncus Arteriosus, Edward type IV and Rastelli operation with Dacron Arterial Conduit Graft under cardiopulmonary bypass on July 3, 1978. The procedures were as follows; 2] Cardiopulmonary bypass: Origin of bronchial arteries excised from descending aorta bilaterally; defects in aorta closed. 2] Horizontal incision made high in right ventricle. 2] Ventricular septal defect [Kirklin type I+II] closed with Teflon patch. 4] Bifurcated dacron arterial graft with pericardial monocusp sutured to the bilateral pulmonary arteries. [Diameter 9 mm: Length 7 cm]. 5] Proximal end of the conduit graft anastomosed to right ventricle. [Diameter 19 mm: Length 5 cm]..Total perfusion time was 220 min. The result of operation was poor due to anastomotic leakage and increased pulmonary vascular resistance resulting acute right heart failure. The patient was died on the operation table. Literatures were briefly reviewed.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.333-341
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• 1978

A 8 year old male was admitted to the Department of Thoracic Surgery, Korea University Hospital on June 22, 1978. The chief complaints were cyanosis and exertional dyspnea since at birth. EKG shows BVH and dextrocardia, phonocardiogram revealed the accentuation of second heart sound in aortic area. Echocardiogram from the left ventricle to the base of the heart, there is a discontinuity between the ventricular septum and the anterior aortic margin with a large aortic root & aortic overriding. His cardiac catheterization data and cardiac angiogram shows situs inversus totalis, dextrocardia, right aortic arch, large ventricular septal defect etc., and finally diagnosed Truncus Arteriosus. Edwards type IV with retrograde aortogram and selective bronchial angiogram. This is the first operative case reported as Rastelli operation for Truncus Arteriosus type IV in the literatures in Korea. Authors have experienced I case of Truncus Arteriosus, Edward type IV and Rastelli operation with Dacron Arterial Conduit Graft under cardiopulmonary bypass on July 3, 1978. The procedures were as follows; 2] Cardiopulmonary bypass: Origin of bronchial arteries excised from descending aorta bilaterally; defects in aorta closed. 2] Horizontal incision made high in right ventricle. 2] Ventricular septal defect [Kirklin type I+II] closed with Teflon patch. 4] Bifurcated dacron arterial graft with pericardial monocusp sutured to the bilateral pulmonary arteries. [Diameter 9 mm: Length 7 cm]. 5] Proximal end of the conduit graft anastomosed to right ventricle. [Diameter 19 mm: Length 5 cm]..Total perfusion time was 220 min. The result of operation was poor due to anastomotic leakage and increased pulmonary vascular resistance resulting acute right heart failure. The patient was died on the operation table. Literatures were briefly reviewed.