• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.279-287
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• 2018

Sealants are an important element of modern architecture and serve as a building protection against weathering by providing barriers against ingress of moisture, air, and other materials. Exposure to a variety of environments often reduces lifespan due to changes in physical, chemical and mechanical characteristics, and UV, humidity, and temperature expansion are important issues that are directly related to durability. In this study, a combined deterioration test chamber was developed to simulate the environment of the open air as an instrument for verifying the durability of structural sealing materials indoors. In order to replicate special weather conditions, such as yellow dust, acid rain, and contamination by microorganisms, it was deemed impossible to replicate the outdoor environment by 100 %, and the results of the results of the results of the external exposure test of the structural sealant and the combined deterioration testing device. As a result of the displacement test of the outdoor exposure test, it was determined that the sealant was breaking apart and that it would be smooth, and the displacement would be up to three times greater than the initial material value of 1 year. The displacement test results of the combined deterioration test device show the tendency to deteriorate, decreasing the elasticity and tensile characteristics. In the case of denatured silicon, the current 400 cycles have been completed to confirm 12 months of degradation of the external exposure. The deformation of the test specimen cannot be verified with the naked eye, so it is considered that the conditions of the specimen are more stable than the silicon sealant. As a result of the outdoor exposure test, if the combined deterioration test device is structured and proposed in the relevant guidance or specification, the anticipated lifespan of 12 months in the actual use environment can be verified indoors and below 3 months later, economically.

• Journal of Korean Society of Forest Science
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• v.40 no.1
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• pp.63-69
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• 1978

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potential1y valuable resourses, As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning their chemical properties. However, the chemical study of tree bark grown in korea have never been undertaken. In the present paper, the studies on the chemical properties of bark comprise carbohydrates, lignin, and extractives, composition of reducing sugars and five essential elements. The results may be summarized as follows: 1. Bark are much richer in quantity of lignin and extractives than the corresponding wood, and are chiefly consisted of lignin, extractives and carbohydrates orderly. It is the same with ash contents. Alcohol-benzene extractives of populus bark are the highest among three genus. 2. Although glucose constitutes the major sugar in both pine and hardwoods bark, in pinus, arabinose and xylose are the next but in hard woods, the next is xylose. 3. Essential elements, Ca and Kjeldahl-N are higher in the bark than in the wood. Ca content is the highest among others, and N,K followed it. Essential elements are higher in Quercus than in Populus and pinus.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.43-49
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• 2004

Background: Acute thoracic aortic dissections involving the aortic arch differ in diagnosis, surgical procedures, and operative results compared to those that do not involve the aortic arch. In general cerebral perfusion under deep hypothermic circulatory arrest (HCA) is performed during the repair of the aortic arch dissection. Here, we report our surgical results of the aortic arch dissection repair using retrograde cerebral perfusion (RCP) and its safety. Material and Method: Between January 1996 and June 2002, 22 consecutive patients with aortic arch dissection underwent aortic arch repair. In 20 of them RCP was performed under HCA. RCP was done through superior vena cava in 19 patients and by systemic retrograde venous perfusion in 1, in whom it was difficult to reach the SVC. When the patient's rectal temperature reached 16 to 18$^{\circ}C$, systemic circulation was arrested, and the amount of RCP amount was 481.1 $\pm$292.9 $m\ell$/min with perfusion pressure of 20∼30 mmHg. Result: There were two in-hospital deaths (4.5%) and one late death (9.1%). Mean circulatory arrest time (RCP time) was 54.0$\pm$ 13.4 minutes (range, 7 to 145 minutes). RCP time has no correlation with the appearance of consciousness, recovery of orientation, or ventilator weaning time (p=0.35, 0.86, and 0.92, respectively). Ventilator weaning was faster in patients with earlier recovery of consciousness and orientation (r=0.850, r=926; p=0.000, respectively). RCP of more than 70 minutes did not affect the appearance of consciousness, recovery of orientation, ventilator weaning time, exercise time, or hospital stay (p=0.42, 0.57, 0.60, 0.83, and 0.51, respectively). Conclusion: Retrograde cerebral perfusion time under hypothermic circulatory arrest during repair of aortic arch dissection may not affect recovery of orientation, ventilator weaning time, neurologic complications, and postoperative recovery.

• Journal of Chest Surgery
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• v.36 no.8
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• pp.559-565
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• 2003

By improving the flow pattern in Fontan circuit, total cavopulmonary connection (TCPC) could result in a better outcome than atriopulmonary connection Fontan operation. For the patients with impaired hemodynamics after atriopulmonary Fontan connection, conversion to TCPC can be expected to bring hemodynamic and functional improvement. We studied the results of the revision of the previous Fontan connection to TCPC in patients with failed Fontan circulation. Material and method: From October1979 to June 2002, eight patients who had failed Fontan circulation, underwent revision of previous Fontan operation to TCPC at Yonsei University Hospital. Intracardiac anomalies of the patients were tricuspid atresia (n=4) and other functional single ventricles (n=4). Mean age at TCPC conversion was 14.0$\pm$7.0 years (range, 4.6~26.2 years) and median interval between initial Fontan operation and TCPC was 7.5 years (range, 2.4~14.3 years). All patients had various degree of symptoms and signs of right heart failure. NYHA functional class was 111 or IV in six patients. Paroxysmal atrial fibrillation (n:f), cyanosis (n=2), intraatrial thrombi (n=2), and protein losing enteropathy (PLE) (n=3) were also combined. The previous Fontan operation was revised to extracardiac conduit placement (n=7) and intraatrial lateral tunnel (n=1). Result: There was no operative death. Major morbidities included deep sternal infection (n=1), prolonged pleural effusion over two weeks (n=1), and temporary junctional lachyarrhythrnia (n=1). Postoperative central venous Pressure was lower than the preoperative value (17.9$\pm$3.5 vs. 14.9$\pm$1.0, p=0.049). Follow-up was complete in all patients and extended to 50,1 months (mean, 30.3$\pm$ 12.8 months). There was no late death. All patients were in NYHA class 1 or 11. Paroxysmal supraventricular tachycardia developed in a patient who underwent conversion to intraatrial lateral tunnel procedure, PLE was recurred in two patients among three patients who had had PLE before the convertsion. There was no newly developed PLE. Conclusion: Hemodynamic and functional improvement could be expected for the patients with Fontan circulatory failure after atriopulmonary connection by revision of their previous circulation to TCPC. The conversion could be performed with low risk of morbidity and mortality.

• Journal of Sericultural and Entomological Science
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• no.12
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• pp.37-45
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• 1970

The processing management forms of our country's filature factories in 1969 are summarized as follows. (1) About 80％ of total cocoon collection is made within 5 days involving peak day, and 10％ of cocoon collection is finished until 3 days before and after the peak day, (2) About 92％ of alive cocoons transported on unpaved road, and about 40％ of the cocoons purchased by all factories are loaded on trucks from common selling station which is far beyond 40km, therefore a new packing system of alive cocoons to drop the damage of cocoon qualities, should be taken. (3) 22％ of all factories in our. country have only low-temperature cocoon drying machine. Therefore the installment of hot-air cocoon drying machine is required urgently. (4) In view of cocoon qualities in our country, the grouping method of cocoon for reeling. taken by about 50％ of the factories at percent, which classify cocoons for reeling as high group (1,2,3,4 grades) and low group(5,6 grades), will have to be replaced by the method tat classify them high group (1,2 grades) middle group (3,4 grades), low group (5,6 grades). (5) The .ratio of cocoon assorting stood about 10％ in multi-ends reeling, about 15％ in automatic reeling, conclusively, the ratio of cocoon assorting for automatic reeling was higher tan that for multi-ends reeling. One person's ability for a day in cocoon assorting reaches to about 80-100kg. (6) Cocoon cooking condition requires the increase of the cooking time, the pressure and temperature used to be prolonged as much as the qualities of cocoons are material cocoon ior automatic and double cocoon machines are treated uncompletely. (7) Automatic silk reeling is being performed at 1-2$^{\circ}C$ lower in reeling water temperature and operated at about twice velocity. (8) The temperature and humidity of rereeling room stood at 25$^{\circ}C$, 67.2％ R.H and 32.3$^{\circ}C$, 51.9％ R.H of rereeling machine are showed, Average rereeling velocity is 233m/min and large reefs charged for one person are 7.5 reels and form of skein used in all factories is double skein. (9) About 73％ of water sources for filature used under-earth water. About 48％ of all filature factories in our country have not yet water purifying equipments. Installation of the equipment for these factories seems to be urgent, (10) Denier .balance, sizing reel, seriplane, are being used in most factories as self-inspection apparatus. (11) More than 90％ of the factories use the vacum tank in rereeling process and about 20％ of them use it in cocoon cooing process (12) Only 21％ of the factories use chemicals in filature process. About all them use "Seracol 100" in cocoon cooking process and "Seracol 500" in rereeling process, (13) Above survey results explain each all factories show large difference in the processing management. Therefore, it is believed that intercommunication through seminar or technical exchange will contribute to the production evaluation of cocoon in our filature industry.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.193-199
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• 2007

Background: Reoperation is usually required for a right ventricle to pulmonary artery conduit obstruction caused by valve degeneration, conduit peel formation or somatic growth of the patient. An autologous tissue reconstruction (peel operation), where a prosthetic roof is placed over the fibrotic tissue bed of the explanted conduit, has been used to manage conduit obstructions at our institute since May 2002. Herein, the early and midterm results are evaluated. Material and Method: Between May 2002 and July 2006, 9 patients underwent obstructed extracardiac conduit replacement with an autologous tissue reconstruction, at a mean of 5.1 years after a Rastelli operation. The mean age at reoperation was $7.5{\pm}2.4$ years, ranging from 2.9 to 10.1 years. The diagnoses included 6 pulmonary atresia with VSD, 2 truncus arteriosus and 1 transposition of the great arteries. The preoperative mean systolic gradient was $88.3{\pm}22.2mmHg$, ranging from 58 to 125 mmHg. The explanted conduits were all Polystan valved pulmonary conduit (Polystan, Denmark). A bioprosthetic valve was inserted in 8 patients, and a monocusp ventricular outflow patch (MVOP) was used in 1 patient. The anterior wall was constructed with a Gore-Tex patch (n=7), MVOP (n=1) and bovine pericardium (n=1). Pulmonary artery angioplasty was required in 5 patients and anterior aortopexy in 2. The mean cardiopulmonary bypass time . was 154 minutes, ranging from 133 to 181 minutes; an aortic crossclamp was not performed in all patients. The mean follow-up duration was 20 months, ranging from 1 to 51 months. All patients were evaluated for their right ventricular outflow pathway using a 3-D CT scan. Resuit: There was no operative mortality or late death. The mean pressure gradient, assessed by echocardiography through the right ventricular outflow tract, was 20.4 mmHg, ranging from 0 to 29.6 mmMg, at discharge and 26 mmHg, ranging from 13 to 36 mmHg, at the latest follow-up (n=7, follow-up duration >1 year). There were no pseudoaneurysms, strictures or thrombotic occlusions. Conclusion: A peel operation was concluded to be a safe and effective re-operative option for an obstructed extracardiac conduit following a Rastelli operation.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.168-179
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• 2007

Background: The recent trend of an increasing number of patients with acute cardiogenic shock or chronic congestive heart failure following myocardial infarction, as well as the considerable number who can not be weaned from cardiopulmonary bypass after open heart surgery, call for immediate efforts to develop affordable ventricular assist devices that are suitable for the Korean physique. Recently, a pneumatic pulsatile ventricular assist device (VAD), named DKUH-75, has been developed by the Department of Biomedical Engineering, in collaboration with the Department of Thoracic and Cardiovascular Surgery of Dankook University College of Medicine. The feasibility of the DKUH-75 VAD was evaluated on the bases of common hemodynamic variables and echocardiographic measurements in pigs, which are subjected to an acute cardiogenic shock state following myocardial infarction, using a novel coronary artery ligation method employing the ischemic preconditioning concept. Material and Method: Acute cardiogenic shock was induced in 10 Yorkshire Landrace Duroc strain pigs by ligating the left anterior descending coronary artery via an ischemic preconditioning process. The hemodynamic variables were monitored, with epicardial echocardiographic measurements performed before and one hour after the ligation. The DKUH-75 VAD was implanted into 5 pigs one hour after the onset of the shock. The hemodynamic variables and echocardiographic measurements were taken one hour after installation of the VAD. Result: The systolic, diastolic and mean systemic arterial pressures were significantly decreased in all the experimental animals one hour after the ligation. The systolic, diastolic and mean pulmonary arterial pressures were increased (Eds note: this completely contradicts the preceding statement? However, if you mean the non-experimental animals this should be stated?). The left ventricular end diastolic pressure (LVEDP) was increased, but the cardiac index decreased, An increase in the left ventricular end systolic dimension and decreases in the fractional shortening and ejection fraction were observed all animals one hour after the coronary artery ligation. In all 5 of the VAD implanted pigs, the systolic and mean systemic arterial pressures were increased, and the pulmonary arterial pressures decreased one hour after the implantation; the LVEDP decreased, but the cardiac index was significantly increased, In the echocardiographic measurements, the left ventricular end systolic dimension decreased after the implantation of the VAD, but the fractional shortening and ejection fraction significantly increased. Conclusion: Significant improvements in the hemodynamic variables and echocardiographic measurements were observed in the 5 VAD implanted animals one hour after installation, which had been subjected to an acute cardiogenic shock state by ligation of the coronary artery, indicating that the DKUH-75 VAD could help in the recovery of the myocardial function. This suggests that the DKUH-75 VAD is feasible in the short term in relation to an acute cardiogenic shock state due to myocardial infarction.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.200-208
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• 2007

Background: The effect of patient-prosthesis mismatch (PPM) on the clinical outcome following aortic valve replacement (AVR) remains controversial. This study compared the surgical outcomes of AVR between patients with a patient-prosthesis mismatch and those having undergone an aortic annular enlargement. Material and Method: Six hundred and twenty seven adult patients, who underwent AVR with stented bioprosthetic or mechanical valves, between January 1996 and February 2006, were evaluated. PPM was defined as an indexed effective orifice area (iEOA) ${\leq}0.85cm^2/m^2$, and Severe if the iEOA${\leq}0.65cm^2/m^2$ PPM was present in 103 (16.4%, PPM group) patients, and severe in 11 (1.8%, SPPM group). During the period of the study, 21 patients underwent an AVR with annular enlargement (AE group). Result: The mean iEOA of the AE group was larger than that of the PPM group ($0.95\;vs.\;0.76cm^2/m^2,\;p=0.00$). The AE group had longer CPB, ACC and operation times than the PPM group, and showed a tendency toward higher operative mortality (14.3% vs. 2.9%, p=0.06). The SPPM group had higher AV pressure gradients (peak/mean) than the AE group (72/45 mmHg vs. 38/25 mmHg, p=0.02/0.06) and suffered more AV related events (AV reoperation or severe aortic stenosis)(45.5% vs. 9.5%, p=0.03). LV masses were not regressed in the patients who experienced an AV related event. Conclusion: During AVR in patients with a small aortic annulus, annular enlargement should be carefully applied taking into account the high risk of operative mortality due to annular enlargement and co-morbidities of patients. Aortic annular enlargement; however, should be considered as an alternative method in patients expected to have a severe PPM after an AVR.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.112-121
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• 1988

Soybean seed coat consisted of three layers, and the aleurone layer was attached to the innermost part of seed coat. It showed the different morphological characteristics with single cell layer compared with many cell layers in barley aleurone layer. The structural difference in aleurone cell among varieties was not detected in this experiment. The hole of middle part of hilum consisted of net formed material in order to pass water and gas. In the experiment, it was not studied whether the varieties with hard seed consist of the same structure or not, but the detailed study on this would be necessary. The activity of acid phosphatase showed a tendency to increase in process of imbibition in distilled water. There was no significant difference in the enzyme activity among the varieties tested, but the enzyme activity of Danyoupkong was slightly higher than that of Hwanggeumkong. In germinability, Danyoupkong is higher than Hwangkeumkong, so it might be attributed to the higher activity. There was no difference in acid phosphatase activity between released from the aleurone cell and accumulated in the aleurone cell from 6 to 12 hours incubation of the medium in the absence of GA$_3$, but the difference was detected after 12 hours incubation. And enzyme activity was the highest in the 18 hours incubation. The increase in the release of acid phosphatase from the aleurone cell would be considered as passive diffusive effect due to the increase in turgo pressure of aleurone cell. The acid phosphatase released from aleurone layer increased greatly after 24 hours incubation of the medium in the presence of GA$_3$ and the accumulation within the aleurone cell decreased linearly after 18 hours incubation. The result indicates that GA$_3$ enhance the rate of enzyme release from aleurone layer, suggests that the aleurone cell wall be digested by the introduction of GA and the digested wall act as the channels for enzyme release.

• The Journal of the Petrological Society of Korea
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• v.6 no.2
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• pp.123-132
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• 1997

In the system $MgO-SiO_2-H_2O$, Talc[$Mg_3Si_4O_{10}(OH)_2$] has been synthesized hydrothermally at 200 MPa, $600^{\circ}C$ from the oxide mixture of the bulk composition of talc. The oxide mixture of the bulk composition of anthophyllite$[Mg_7Si_8O_{22}(OH)2]$ converted to talc, enstatite $(MgSiO_3)$, quartz at 200 MPa, $750^{\circ}C$ with excess of $H_2O$. In low to medium pressure metramorphism, enstatite-talc assemblage is metastable relative to anthophyllite with the reaction talc + 4 enstatite=anthophyllite (Greenwood, 1963). The high temperature stability of talc is bounded with the dehydration reaction to anthophyllite rather than that to enstatite(Greenwood, 1963; Chernosky et al., 1985). Therefore our experiment result assemblage, enstatite-talc-quatz at 200 MPa, $750^{\circ}C$ from oxide mixture of bulk compostion of anthophyllite is metastable assemblage. The hydrothermal experiment performed at 41 to 243 MPa, 680 to $760^{\circ}C$ with the starting material composed of synthetic talc, enstatite and quartz. Talc or enstatite grows during the runs and no extra phases including anthophyllite nucleated. Based on the increase or decrease of the each phase from run products, one of the possible reactions is talc=3 enstatite+quartz+H_2O$. The reversal bracket of the reaction is 699 to $700^{\circ}C$ at 100 MPa. Talc is stable up to $740^{\circ}C$ at 200 MPa and enstatite grow at $680^{\circ}C$, 40 MPa and at $760^{\circ}C$, 250 MPa. Though the high temperature limit of talc around 200 MPa is bounded thermodynamically by the reaction, 7 talc=3 anthophyllite+4 quartz+4 H_2O$, talc persisted throughout the previous reaction up to the reaction, talc=3 enstatite+quartz+$H_2O$.