• Journal of Chest Surgery
• /
• v.39 no.12 s.269
• /
• pp.891-899
• /
• 2006

Background: This study is to evaluate the safety of ATS valve by examining the clinical results of ten-years experience. Material and Method: From July 1995 to March 2005, we reviewed 305 patients with ATS valve implantation. Mean age was $49.8{\pm}11.7$ years and 140(45.6%) males were included. Etiologies were rheumatic diseases in 207 cases(67.4%), degenerative changes in 57 cases(18.6%), valve dysfunction in 23 cases(7.5%) and infective endocarditis in 14 cases(4.6%). AVR was performed in 72 patients(23.5%), MVR in 156 patients (50.8%), DVR(AVR+MVR) in 63 patients(20.5%) and TVR in 16 patients(5.2%). Result: There were 9 operative mortalities(2.9%). Follow up period was $56.5{\pm}34.0(0{\sim}115)$ months and 96.4% patients were followed up with 9 late deaths. Five and ten years survival rates were $94.9{\pm}1.3%,\;91.2{\pm}2.3%$ using Kaplan-Meier's methods. Valve related event free survival rates in 5 and 10 years were $90.8{\pm}2.0%$ and $86.9{\pm}3.2%$. There were 16 anticoagulation-related hemorrhages, 6 thromboembolisms, 3 prosthetic valve endocarditis and 1 paravalvular leakage. NYHA class improved after operation(p<0.05). Postoperative echocardiography showed significant decrease in LA size, LVEDD and IVESD(p<0.01). Patients with 19 and 21 mm valve showed significantly higher transvalvular pressure gradient in aortic position(p<0.001, p<0.001). Conclusion: ATS valve showed good hemodynamic results with few valve related complications and thus can be used with acceptable risk.

• Journal of Chest Surgery
• /
• v.42 no.1
• /
• pp.46-52
• /
• 2009

Background: Vascular injuries to the extremities are potentially devastating and they can lead to limb loss and mortality if they are not appropriately managed. The vascular trauma caused by traffic and industrial accidents has recently increased according to the developing industry and transport system in Korea. Early recognition and treatment of these injuries are mandatory to achieve satisfactory outcomes. Material and Method: We retrospective reviewed 43 patients with vascular injuries that were due to blunt and penetrating trauma and they underwent emergency operations from January of 1998 to December of 2006. Result: There were 38 men and 5 women patients with a mean age of $42.0{\pm}16.8$ years (range: 17~77). The cause of vascular injuries were 28 traffic accidents (65%), 6 industrial accidents (14%), 6 glass injuries (14%) and 3 knife injuries (7%). The average time from admission to the operating room was $319.0{\pm}482.2$ minutes (range: 27~2,400 minutes). The average time from admission to discharge was $53.1{\pm}56.0$ days (range: 2~265 days). The anatomic injuries included the femoral artery in 16 cases (37%), the popliteal artery in 8 cases (19%), the brachial artery in 8 cases (19%), and the subclavian and axillary arteries in 7 cases (16%). The associated injuries were 23 bone fractures (53%), 18 muscle injuries (42%) 5 nerve injuries (12%) and 11 vein injuries (26%). The operation methods were 20 end to end anastomoses (46%), 16 interposition grafts (36%), 2 repairs with using patches (5%) and 5 others (12%). The number of amputations and cases of mortality were 3 cases (7%) and 4 cases (9%), respectively. Conclusion: Minimizing ischemia is an important factor for maximizing salvage of extremities. Prompt diagnosis and treatment can reduce the amputation and mortality rates.

• Journal of Chest Surgery
• /
• v.42 no.2
• /
• pp.135-140
• /
• 2009

Background: Chronic rejection after a cardiac allograft usually occurs about six months after the operation. Vasculopathy due to chronic rejection causes atherosclerosis in the coronary artery of the transplanted heart and then this causes myocardial injury. We intended to discover and document those findings that occur in a transplanted ascending aorta. Material and Method: In rats weighting $200{\sim}300gm$ (Spraque-Dawley rat), we carried out heterotopic heart allo-transplantation with the modified Ono-Lindsey method and then the rats were administrated cyclosporine (10mg/kg/day). After three months survival, we acquired biopsy materials from the native ascending aorta and the allo-transplanted ascending aorta and we compared them. We classified each severity of 1) intimal thickening, 2) medial hyperplasia, 3) medial calcification, 4) medial inflammation and 5) chondroid metaplasia, which are specific biopsy findings for chronic rejection after a cardiac allograft. Each severity was classified, according to the opinion of one pathologist, in the native ascending aorta biopsies (n=9) and the allo-transplanted ascending aorta biopsies (n=13). The data of the control group and the study group were statistically analyzed with using the Mann-Whitney test (SPSS version 12.0 window). Result: The important changes of the allo-transplanted aorta were intimal thickening (p<0.0001), medial calcification (p=0.045), medial inflammation (p<0.0001) and chondroid metaplasia (p=0.045), but not medial hyperplasia (p=0.36). Conclusion: Cardiac allograft vasculopathy was seen in the transplanted ascending aorta, the same as was seen in the coronary artery, after allograft cardiac transplantation. We have reached the conclusion that chronic rejection also progresses in the aorta.

• Journal of Chest Surgery
• /
• v.42 no.1
• /
• pp.34-40
• /
• 2009

Background: The principal surgical technique for treating an abdominal aortic aneurysm since the 1960s has been the transperitoneal approach, yet there have been some recent studies that have reported improved surgical results with using the retroperitoneal approach. However, there are only limited clinical Korean studies that have, compared between the transperitoneal and retroperitoneal approaches. Material and Method: This study included 36 patients who had been diagnosed as having an aneurysm of the abdominal aorta and they were surgically treated between January 2001 and July 2007. The patients were subdivided into the retroperitoneal approach group (n=17) and the transperitoneal approach group (n=19), and they were compared in terms of the preoperative risk factors, the postoperative complications and the operative mortality. The risk factors of operative mortality risk and long-term survival for the 36 patients were assessed by the Kaplan-Meier method. Result: There were no significant differences between the groups in terms of gender, age, the underlying disease, a history of smoking, rupture of aneurysm, the preoperative symptoms, the operation time and the incidence of postoperative complications. However, the duration of postoperative fasting, the number of days of having an indwelling nasogastric tube and the length of the stay in the intensive care unit were significantly short for the retroperitoneal approach group (p<0.05). There was a 16.7% rate of operative mortality (6/36) and five of the deaths were attributed to preoperative ruptured aneurysm. On univariate analysis, a higher preoperative serum creatinine level (SCr ${\geq}$1.8 mg/dL, p=0.016) and ruptured aneurysm (p<0.001) were the significant risk factors of operative mortality. As assessed by the Kaplan-Meier method, the long-term survival was comparable between the groups and the five-year survival rate of all the patients was 57.5%. Conclusion: In the present study, a retroperitoneal approach has several advantages such as a shorter intensive care unit stay, a shorter duration of postoperative fasting and a shorter duration of an indwelling nasogastric tube. Therefore, unless there is any contraindication for a retroperitoneal approach, it could be considered as a primary surgical access for repairing an abdominal aortic aneurysm.

• Journal of Chest Surgery
• /
• v.40 no.11
• /
• pp.733-744
• /
• 2007

Background: There is a controversy regarding the pathogenesis and management principle of an acute intramural hematoma (IMH) of the aorta, Recent studies have reported intimal defects in many patients diagnosed with IMH, and suggested that intimal defects play important roles in the pathogenesis, progression of the pathology, and prognosis. Material and Method: This study reviewed the preoperative and postoperative computed tomography (CT) scan images of 36 patients who underwent surgical treatment for Stanford type A acute IMH of the aorta. The surgical findings were also reviewed retrospectively from the medical records. Result: In 15 patients (41.7%), the findings suggestive of the intimal defects were found in the preoperative CT. During the operation, 20 patients (72.2%) were found to have small intimal defects in the ascending aorta or the arch, of which 13 patients (50.5%) did not have the CT findings suggestive of intimal defects. In 17 patients, the intimal defects were located in the aortic arch or distal ascending aorta, where a gross examination would have been impossible without total circulatory arrest. In all patients, the intimal defects identified were included in the resected aortic segment, or locally closed. Follow-up CT at 4 months or longer after surgery showed that the IMH in the descending aorta had disappeared or was markedly improved. Conclusion: Most patients undergoing surgical treatment for acute type A IMH had intimal defects. This suggests that a large proportion of IMH might have a similar pathogenic mechanism as classic dissection. Consequently, it is believed that those two entities of acute aortic syndrome should be treat-ed using the same principles.

• Economic and Environmental Geology
• /
• v.51 no.2
• /
• pp.185-201
• /
• 2018

Nuclear power plants(NPP) are constructed and operated to ensure safety against natural disasters and man-made disasters in all processes including site selection, site survey, design, construction, and operation. This paper will introduce a series of efforts conducted in Korea Hydro and Nuclear Power Co. Ltd., to assure the safety of nuclear power plant against earthquakes and other natural hazards. In particular, the present status of the earthquake, fault, and slope safety monitoring system for nuclear power plants is introduced. A earthquake observatory network for the NPP sites has been built up for nuclear safety and providing adequate seismic design standards for NPP sites by monitoring seismicity in and around NPPs since 1999. The Eupcheon Fault Monitoring System, composed of a strainmeter, seismometer, creepmeter, Global Positioning System, and groundwater meter, was installed to assess the safety of the Wolsung Nuclear Power Plant against earthquakes by monitoring the short- and long-term behavioral characteristics of the Eupcheon fault. Through the analysis of measured data, it was verified that the Eupcheon fault is a relatively stable fault that is not affected by earthquakes occurring around the southeastern part of the Korean peninsula. In addition, it was confirmed that the fault monitoring system could be very useful for seismic safety analysis and earthquake prediction study on the fault. K-SLOPE System for systematic slope monitoring was successfully developed for monitoring of the slope at nuclear power plants. Several kinds of monitoring devices including an inclinometer, tiltmeter, tension-wire, and precipitation gauge were installed on the NPP slope. A macro deformation analysis using terrestrial LiDAR (Light Detection And Ranging) was performed for overall slope deformation evaluation.

• Journal of Conservation Science
• /
• v.30 no.2
• /
• pp.137-148
• /
• 2014

Large scale anoxic chamber system(volume $28m^3$) was developed and installed at The National Folk Museum of Korea for the first time in Korea. In order to get optimal anoxic treatment condition, we compared the disinfection of adults, larvae and eggs of cigarette beetles using nitrogen and argon. The time for complete disinfection of cigarette beetles in pine wooden blocks exposed to nitrogen at oxygen concentration 0.01% and 50% in relative humidity were 15 days at $20^{\circ}C$, 10 days at $25^{\circ}C$, and 7 days $30^{\circ}C$. Time were 10 days at $20^{\circ}C$, 7 days at $25^{\circ}C$, and 5 days $30^{\circ}C$ in argon anoxic atmosphere. From the mortality of cigarette beetles, optimal disinfection condition was oxygen concentration 0.01%, $25^{\circ}C$ in temperature, 50% in relative humidity and exposure time 21 days at nitrogen atmosphere. And when large scale anoxic chamber system was supplied nitrogen by nitrogen generator for anoxic treatment of many collections or large collections, it could be operated stably. To verify optimal disinfection condition, museum insects(adults, larvae, pupae and eggs of cigarette beetles in pine wooden blocks, cotton fabrics and Korean paper book, adults and larvae of drugstore beetles in pine wooden blocks, cotton fabrics and Korean paper book, larvae of varied carpet beetles in pine wooden block and silk fabrics, adults and larvae of hide beetles and adults of rice weevils in breeding boxes) which exposed at optimal disinfection condition, were completely killed.

• Journal of Biomedical Engineering Research
• /
• v.19 no.6
• /
• pp.617-622
• /
• 1998

A cryotherapy system using cold air was developed. The developed system had superior low-temperature characteristics with various flow rates and nozzle sizes, and used R-404A, as a coolant, which has no destructive effects of Ozone layers. Flow rates and the treatment time can be easily altered during the operation. In addition, and alarm system was designed for the overload, overheat, and over-charge of the machine. For clinical applications, skin temperatures, intra-articular temperatures of the knee joint and intra-muscluar temperatures of the gluteal muscles were measured during and after the cryotherapy. After a 5-minute therapy, skin and intra-articular temperatures decreased by $23.3{\pm}4.7 and 4.1 {\pm}1.0^{circ}C$, respectively. A 5-minute cryotherapy was good enough to maintain low intra-articular temperatures for 2-3 hours. Resting intra-muscular temperatures in 2, 4, and 6cm deep in the gluteal muscle were $36.5{\pm}1.2, 36.9{\pm}0.2, 37.1{\pm}0.2^{circ}C$, respectively (p<0.05). Lowest temperatures in 2, 4, and 6cm depth were $35.1{\pm}0.7, 36.2{\pm}0.4, 36.9{\pm}0.3^{circ}C$, respectively (p<0.05). Temperatures after a 2-hour cold air application on the skin and in the muscle in dept도 of 2, 4, and 6cm were $32.2{\pm}1.1, 36.2{\pm}0.5, 36.6{\pm}0.3, 36.9{\pm}0.3^{circ}C$respectively (p<0.05). Temperatures on the skin and in the muscle significantly decreased after 2 hours, compared with before cold air application (p<0.05). The intra-muscular temperature was changed more slowly than the skin temperature, and the deeper the muscle, the lesser temperature changes. The effect of a 5-minute cold air application lasts up to 2 hours, and it seems that the rebound-rise of the temperature dut to the reactive vasodilatation does not occur in the gluteal muscle.

• Journal of Animal Science and Technology
• /
• v.44 no.4
• /
• pp.459-474
• /
• 2002

The purpose of this study was to establish the optimal operation condition of the natural evaporation system(NES) which was used for reducing swine slurry. Especially the main point of this study is to estimate the effect of climate condition(clear & rainy) and spray type(batch & flow) for the evaporation rate of swine slurry applying the NES in summer. Experiment was performed from June to August, which was generally regarded as summer in Korea, with the spray type of batch in 2000 and that of flow in 2001. As a result of experiment for batch and flow type, the averaged evaporation rate was measured into 2.71 and 3.59 l/ton . $m^2$ . day on clear days and 0.62 and 0.66 l/ton . $m^2$ . day on raint days, respectively. Based on the calculated evaporation rate by the climate condition and the spray type, it was proved that the averaged reduction rate for total input(1t/day) were 15.99% and 3.19% on clear and rainy days and the evaporation rate of the flow type was superior to that of the batch type by 5%, approximately. Therefore, it was concluded that the supplementary equipment, such as fan, should by operated in rainy days and the spray type of flow rather than that of batch should be recommended to increase the evaporation rate in the natural evaporation system(NES).

• Journal of Bio-Environment Control
• /
• v.16 no.3
• /
• pp.210-216
• /
• 2007

A study was conducted to find mechanism and spray characteristics of a mini-sprinkler with downward spray to develop a new design type to be able to prevent drop water. The experiments were executed in a plastic greenhouse to minimize the effect of the wind. Data was collected at five different operation pressures and at 4 different raiser heights. Spray characteristics of the sprinkler such as effective radius, effective area, mean application depth, absolute maximum application depth, effective maximum application depth and coefficient of variation were determined. In order to analyze the mechanism and packing supporter of sprinkler, the numerical simulation using ABAQUS was performed. The optimum pressure for preventing drop water was determined.