• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.5
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• pp.401-412
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• 2016

It is extremely difficult to apply conventional grouting methods to subsea tunnelling construction in the high water pressure condition. In such a condition, the rapid artificial freezing method can be an alternative to grouting to form a watertight zone around freezing pipes. For a proper design of the artificial freezing method, the influence of salinity on the freezing process has to be considered. However, there are few domestic tunnel construction that adopted the artificial freezing method, and influential factors on the freezing of the soil are not clearly identified. In this paper, a series of laboratory experiments were performed to identify the physical characteristics of frozen soil. Thermal conductivity of the frozen and unfrozen soil samples was measured through the thermal sensor adopting transient hot-wire method. Moreover, a lab-scale freezing chamber was devised to simulate freezing process of silica sand with consideration of the salinity of pore-water. The temperature in the silica sand sample was measured during the freezing process to evaluate the effect of pore-water salinity on the frozen rate that is one of the key parameters in designing the artificial freezing method in subsea tunnelling. In case of unfrozen soil, the soil samples saturated with fresh water (salinity of 0%) and brine water (salinity of 3.5%) showed a similar value of thermal conductivity. However, the frozen soil sample saturated with brine water led to the thermal conductivity notably higher than that of fresh water, which corresponds to the fact that the freezing rate of brine water was greater than that of fresh water in the freezing chamber test.

• Journal of Chest Surgery
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• v.39 no.6 s.263
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• pp.427-433
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• 2006

Background: Current vascular prostheses are considered still inadequate for reconstruction of small-diameter vessels. To evaluate the potential use of xenograft vessels as small diameter arterial grafts, we implanted porcine vessels in goats. The grafts were treated with two different processes, freezing and acellularization, before implantation, and gross inspection as well as microscopic examination followed after a predetermined period. Material and Method: Bilateral porcine carotid arteries were harvested and immediately stored at $-70^{\circ}C$ within tissue preservation solution. One of them was designated as frozen xenograft vessel. The other one was put on acellularization process using NaCl-SDS solution and stored frozen until further use. Grafts were implanted in the place of carotid arteries of the same goat. The grafts have remained implanted for 1, 3, and 6 months in three animals, respectively. Periodic ultrasonographic examinations were performed during the observation period. After explantation, the grafts were analyzed grossly and histologically under light microscope. Result: All animals survived the experimental procedure without problems. Ultrasonographic examinations showed excellent patency of all the grafts during the observation period. Gross examination revealed nonthrombotic, patent lumens with smooth surfaces. Microscopic examinations of the explanted grafts showed cellular reconstruction at the 6-month stage in both grafts. Although more inflammatory responses were observed in the early phase of frozen xenografts, there was no evidence of significant rejection. Conclusion: These findings suggest that porcine xenograft vessels, regardless of pre-implantation processes of acelluarization or freezing, can be acceptably implanted in goats, although short duration of observation in a small number of animals may limit this study.

• Journal of Chest Surgery
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• v.35 no.5
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• pp.329-335
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• 2002

Background: The surgical technique for biventricular assist device(BVAD) implantation has mainly consisted of cannulation procedures. A median sternotomy has been the technique of choice as it gives a surgeon an excellent exposure of the heart. However, considering that most patients require a future sternotomy or already have a previous sternotomy, sternotomy-related complication remains a major concern in BVAD implantation. Based on this consideration as well as the clinical experiences of conventional heart surgery, the authors have hypothesized that the cardiac chambers for BVAD cannulation can be approached from the right side of the heart. The purpose of this studs to develop a novel surgical technique of right thoracotomy for BVAD implantation in an animals study. Material and Method: For last two years, 16 (11 calves, 3 canines, and 2 sheep) out of 30 experimental animals with AnyHeart implantation underwent a right thoracotomy. The device was used as an implantable BVAD in 14 animals, a wearable BVAD in 1, and an implantable LVAD in 1. The chest cavity was entered through the 4th intercostal space or the 5th periosteal bed. As for the BVAD use, a right inflow cannula was inserted into the right atrial free wall and a right outflow cannula was grafted onto the main pulmonary artery. A left inflow cannula was inserted into the interatrial groove and a left outflow cannula was grafted on the innominate artery of the ascending aorta. The connecting tubes were brought out through the thoracotomy wound and connected to the pump located in the subcutaneous pocket at the right flank. Result: Except for the 5 animals for a lilting test or during the early learning curve, all recovered smoothly from the procedures. The inflow drainage allowed the pump output 6.5 L/min at the maximum with 3-3.5 L/min in an average. Of the survivors, there noted no procedure-related mortality or morbidity. Necropsy findings demonstrated the well-positioned cannula tips in the each cardiac chamber

• Journal of Chest Surgery
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• v.43 no.2
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• pp.127-132
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• 2010

Background: Femoropopliteal artery bypss grafting is an effective form of treatment for infrainguinal artery occlusive disease in those patients who have either intermittent claudication or resting critical ischemia. The objective of this analysis was to evaluate the long-term patency of a femoropopliteal bypass graft that is classified as an above-the-knee saphenous vein graft or an above-the-knee PTFE (polytetrafluoroethylene) graft. Material and Method:From January 1998 to February 2005, 103 above-the-knee femoro-popliteal bypasses were performed on 87 patients. There were 74 male and 13 female patients with a mean age of $65.7{\pm}9.69$ (range: 31~82). The surgical indications were intermittent claudication in 65 cases (74.7%), foot ulceration in 2 cases (2.3%), foot necrosis in 10 ases (11.5%) and toe necrosis in 10 cases (11.5%). For the bypass graft, a reversed saphenous vein was used in 31 limbs and a polytetrafluoroethylene (PTFE) prosthesis was used in 72 limbs (6 mm: 27 limbs, 8 mm: 45 limbs). The perioperative risk factors were diabetes mellitus in 33 cases (37.9%), hypertension in 47 cases (54.0%), a history of ischemic heart disease in 13 cases (14.9%) and smoking in 72 cases (82.8%). Result:There were three perioperative deaths (3.4%) and seven late deaths (8.3%). Major leg amputation was necessary in 12 patients (13.8%) during the entire course of the study. The primary patency rate at 5 years for the vein grafts, the 8 mm-PTFE grafts and the 6 mm-PTFE grafts were 84.7%, 77.4% and 74.2%, respectively and the overall primary patency rate was 78.7%, and there were no significant statistical differences among the graft groups. By using multivariate analysis, the number of patent tibial arteries was determined to be a significant factor that influenced the primary graft patency rate (p<0.005), but risk factors such as diabetes mellitus, ischemic heart disease, smoking and age had no statistically significant affect on the primary graft patency rates. Conclusion: The great saphenous vein is considered the most durable conduit for infrainguinal revascularization, but the overall results of this study show that saphenous vein and PTFE grafts have comparable patency rates when used above the knee in patients with claudication or critical ischemia. The use of PTFE above the knee is a reasonable alternative for a femoro-poplitael bypass and it is associated with acceptable long term patency rates.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.261-266
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• 2003

Background: Surgery of abdominal aortic aneurysm revealed high operative mortality. We reviewed our 11-years' experiences of abdominal aortic aneurysm operation and wish to obtain information on the treatment. Material and Method: From Jan. 1990 to Dec. 2000, 48 patients were operated due to abdominal aortic aneurysm in Yonsei Cardiovascular Center Mean age was $62.8{\pm}12.7$ and there were 40 males and 8 females. Among 48 patients, nine patients had ruptured abdominal aortic aneurysm, and mean aneurysm diameter of non-ruptured cases was $8.8{\pm}2.4$cm. Result: There were 6 early deaths, and early mortality was 12.5%. Among 9 patients of preoperative aneurysm rupture, three patients died (33.3%), and among 39 patients of non-ruptured cases, 3 patients died (7.7%). Among preoperative variables, age (p<0.05), preoperative BUN level (p<0.05), and DM (p<0.05) were risk factors of early mortality. Among discharged 42 patients, 40 patients were followed up (f/u rate=95.2%) and mean follow up was $3.6{\pm}0.2$ years. During follow up periods, five patients died (late mortality=11.9%), and Kaplan-Meier survival analysis revealed $81.7{\pm}7.6$% survival rate at five and ten year. Linealized incidence of graft related event was 3.53% per patient-year. Conclusion: Surgical mortality of ruptured abdominal aortic aneurysm was higher than non-ruptured cases; therefore, early resection of the aneurysm can decrease the surgical mortality.

• Journal of Chest Surgery
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• v.39 no.4 s.261
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• pp.261-268
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• 2006

Background: Current vascular prostheses are still inadequate for reconstruction of small-diameter vessels. Autologous pericardium can be a good alternative for this purpose as it already possesses good blood compatibility and shows a mechanical behavior similar to that of natural arteries. However, the clinical use of autologous pericardial tissue as a small-diameter vascular graft has limitations due to mixed outcomes from uncertain biological behavior and difficulty to gain reliable patency results in animal experiments. To study this issue, we implanted fresh and glutaraldehyde-treated autologous pericardium as small-diameter arterial grafts in dogs, and compared their time-related changes histologically. Material and Method: As a form of 5mm-diameter arterial graft, one pair of autologous pericardial tissue was used for comparison between the glutaraldehyde-treated and the glutaraldehyde-untreated grafts in the bilateral carotid arteries in the same dog. The patency of the grafts were evaluated at regular intervals with Doppler ultrasonography. After the predetermined periods of 3 days, 2 weeks, 1 month, 3 months and 6 months, the grafts in each animal were explanted. The retrieved grafts were processed for light and electron microscopic analyses following gross observation. Result: Of 7 animals, 2 were excluded from the study because one died postoperatively due to bleeding and the other was documented as one side of the grafts being obstructed. All 10 grafts in the remaining 5 dogs were patent. Grossly, a variable degree of thromboses were observed in the luminal surfaces of the grafts at 3 days and 2 weeks, despite good patency. Pseudointimal smooth blood-contacting surfaces were developed in the grafts at f month and later. By light microscopy, mesothelial cell layers of the pericardial tissue were absent in all explanted grafts. Newly formed endothelial cell layers on the blood-contacting surface were observed in both the glutaraldehyde-treated and fresh grafts at 3 months and later. The collagen fibers became degraded by fragmentation in the fresh graft at 1 month and In the glutaraldehyde-treated graft at 3 months. At 6 months, the collagen layers were no longer visible in either the glutaraldehyde-treated or fresh grafts. By electron microscopy, a greater amount of coarse fibrin fibers were observed in the fresh grafts than in the glutaraldehyde-treated grafts and, more compact and well-arrayed layers were observed in the glutaraldehyde-treated grafts than in the fresh grafts. Conclusion: The glutaraldehyde-treated small-diameter pericardial arterial grafts showed a better endothelialization of the blood-contacting surface and a slower fragmentation of the collagen layers than the fresh grafts, although it has yet to be proven whether these differences are so significant as to affect the patency results between the groups.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.4
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• pp.1-17
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• 2018

This study was conducted to interpret the landscape of Songge Byeoleop(Korean villa) garden at Jogyedong, Bukhansan near Seoul which was built in the mid 17C. to restore through the literature reviews and field surveys. The results were as follows; Songge Byeoleop garden was a royal villa, constructed at King Injo24(1646) of Joseon dynasty by prince Inpyeong(麟坪大君), Lee, Yo(李?, 1622~1658), the third son of King Injo who was a brother of King Hyojong. It was a royal villa, Seokyang-lu under Mt. Taracsan of Gyendeokbang, about 7km away in the straight line from main building. It was considered that the building system was a very gorgeous with timber coloring because of owner's special situation who was called the great prince. The place of Songge Byeoleop identity and key landscape of the place were consisted with Gucheon waterfall and the sound of the water with multi-layered waterfall which might be comparable to the waterfall of Yeosan in China. After the destruction of the building, the place was used for the royal tomb quarry, but there was a mark stone for forbidden quarry. The Inner part of Songge Beoleop, centered with Jogedongcheon, Chogye-dong, composted beautifully with the natural sceneries of Gucheon waterfall, Handam and Changbeok, and artificial structures, such as Bihong-bridge, Boheogak, Yeonghyudang and Gyedang. In addition, the existing Chinese characters, 'Songge Beoleop' and 'Gucheoneunpog' carved in the rocks are literary languages and place markings symbolizing with the contrast of the different forests and territories. They gave the names of scenery to the rock and gave meaning to them. Particularly, Gucheon waterfall which served as a visual terminal point, is a cascade type with multi-staged waterfall. and the lower part shows the topographical characteristics of the Horse Bowl-shaped jointed with port-holes. On the other hand, the outer part is divided into the spaces for the main entrance gate, a hanging bridge character, a bridge connecting the inside and the outside, and Yeonghyudang part for the purpose of living. Also in the Boheogak area, dual view frame structures are made to allow the view of the four sides including the width and the perimeter of the villa. In addition, at the view point in Bihong-bridge, the Gucheon water fall divides between the sacred and profane, and crosses the Bihong-bridge and climbs to the subterranean level.

• The Journal of Korean Philosophical History
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• no.32
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• pp.43-78
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• 2011

The two schools which eventually came to form the "Northerners party" in the middle period of the Joseon dynasty, were Nam'myeong school and Hwadam school. Nam'myeong's philosophy, which emphasized the importance and merit of acting upon respect and righteousness(敬義), encouraged many people to organize righteous militias during the war with the Japanese in the 1590s, and when Jeong In-hong established himself as the leader of the Northerners party during the reign of King Gwang'hae-gun, the philosophy of the party and the school continued to thrive. Also, Hwadam's philosophy, which tried to understand Neo-Confucianism from a flexible point of view and demonstrated a level of openness toward it, had a considerable influence upon the Northerners school as well. It seems Nam'myeong Jo Shik and Hwadam Seo Gyeong-deok were the ones who ultimately enabled the Northerners party to be more active in their operations of the government and also to approach more freely toward the ideology of Neo-Confucianism. Prime examples of the party's stance and attitude, and also of the school's philosophy and perception of the world, were figures like Jeong In-hong and Heo Gyun from the 'Majority Northerners(大北) party,' and Kim Shin-guk and Nam I-gong from the 'Minority Northerners(小北) party.'Since the time of King Injo's ascension to the throne in 1623, the philosophical society of Joseon came to be occupied by schools who were deeply committed and dedicated to the teachings of Ju Hi and his Neo-Confucianism, such as the Twe'gye and Yulgok schools, and as a result the Northerners' philosophy was pushed away from its former formidable status. Their political philosophy was also partially responsible for their fall, as they believed only them were the ideal Confucian figures(君子黨), and never appreciated the stances of other political factions. In the middle of the 17th century, passing through a war with the Manchurian Qing dynasty as well, they further became a mere undercurrent. Yet their thinking and philosophy partially survived, as it managed to affect and influence the Southerner school scholars who were living in the vicinity of the capital in the mid and late 17th century, as well as the "Shilhak" scholars such as Yi Ik/李瀷 in the 18th century, on a certain level. The Northerners faction was a party and a school which led the political and philosophical societies of Joseon, alongside the Westerners and Southerners, in the middle period of the Joseon dynasty. Recently, studies of Jo Shik and Seo Gyeong-deok, figures who were the roots of the Northerners faction, and studies of how the Northerners' political philosophy was inherited to the following generations, have been published and announced. All these efforts will enrich future studies dealing with the political history and philosophical history of the middle and latter periods of the Joseon dynasty.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.753-757
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• 2010

We report hereon a case of double bypass of the esophagus and descending thoracic aorta for the treatment of esophagopleural fistula and aortopleural fistula due to an infected aortic aneurysm after esophageal rupture. A 48 year old man was diagnosed as having esophageal rupture after an accidental explosion. Although he had been treated by esophageal repair and drainage at another hospital, the esophageal leakage could not be controlled and subsequent empyema developed in the left pleura. Further, bleeding from the descending thoracic aorta had developed and he was managed with endovascular stent insertion to the descending thoracic aorta. He was transferred to our hospital for corrective surgery. We performed esophago - gastrostomy via the substernal route, without exploring posterior mediastinum and we let the empyema resolve spontaneously. While he was being managed postoperatively Without any signs and symptoms of infection, sudden bleeding developed from the left pleural cavity. After evaluation for the bleeding focus, we discovered an Infected aortic aneurysm and an aortospleural fistula at the stent insertion site. We performed a second bypass procedure for the infected descending thoracic aorta from the ascending aorta to the descending abdominal aorta via the right pleural cavity. We found leakage at the distalligation site during the immediate postoperative period, and we occluded the leakage using a vascular plug. He discharged without complications and he is currently doing well without any more bleeding or other complications.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.207-214
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• 2002

The purpose of this study was to examine the putter head movement during the putting strokes. Highly skilled 5 golfers(less than 3 handicaps) and 5 novice golfers(having no golf experience) participated in this study. A target distance was 3 m. Movements of the putter head were recorded at 60 Hz with two video cameras(1/500 shutter speed). The results showed that the angle of the clubface of expert golfers was almost 1 degree, but the novice golfers were more than 6 degrees. Expert golfers moved their hands faster than the head movement, therefore the clubface was not opened during impact. However, the novice golfers moved their hands slower than the head movement, therefore the clubface was opened during impact. The ratio of input and output angles of total movement was 1:3-4, however, the ratio of input and output angles of impact zone was 1:2. The angle of normal vector of expert golfers was less than the angle of normal vector of novice golfers.