• Title/Summary/Keyword: Failure analysis

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A Study on the Physcial and Mechanical Properties of Hot - Compressed Wood (열압처리(熱壓處理) 목재(木材)의 이학적(理學的) 성질(性質)에 관(關)한 연구(硏究))

  • Park, Young-Kyu;Chung, Dae-Kyo
    • Journal of the Korean Wood Science and Technology
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    • v.15 no.4
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    • pp.45-58
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    • 1987
  • This study was carried out to improve the physical and mechanical properties of Pupulus alba $\times$ glandulosa treated by the heat and compression. The results obtained were as follows. 1. The specific gravity of the wood was conspicuously increased by the lincreasing of pressing level. 2. The shrinkage of the wood was increased. by the increasing of pressing level. The radial shrinkage was 6.41-8.81%, the tangential shrinkage was 8.98-19.81 %, and the longitudinal shrinkage was 1.46-1.91 %. Comparing to the untreated stock, the rate of increase was 48.7-104.4% in radial direction. 1.7-124.4% in tangential direction and 60.4-109.9% in longitudinal direction, respectively. 3. The rate absorption of 30% compressed stock was Similar to that of untreated stock. but the rate of absorption of 40 % or more compressed stock was increased highly. 4. The thickness swelling of the wood was not changed in radial direction at pressing level, but was conspicuously increased in tangential direction under the pressing level of 40% and 50%. 5. The heat and compression treatment affected on the mechanical properties of the wood. The longitudinal compressive strength was increased under the pressing level of up to 40%, but was decreased under the pressing level of 50%. The bending strength was not changed under the compression percentage of up to 30%, but was decreased under the pressing level of 30% or more. And, the absorbed energy in impact bending was increased to 128% under the pressing level of up to 30%, but was decreased under the pressing level of 30% or more. Conclusionly, the mechanical properties of the wood was improved by the heat and compression treatment, but the strength of the wood was decreased under the pressing level of a certain level or more(in this study, pressing level of 30% or more). This was because of the wood deterioration due to the deformation(shrinkage, crack, failure) of wood tissues induced by the heat and compression treatment, the heat analysis of wood components induced by the heating, and the drop of the degree of polymerization.

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Clinical Analysis to the Early Results of the CABG (관상동맥우회술의 조기 성적에 대한 임상적 고찰)

  • Kim, Dae-Sig;Yang, Jin-Young;Koo, Won-Mo;Moon, Seung-Chul;Lee, Gun;Lee, Hyeon-Jae;Lim, Chang-Young
    • Journal of Chest Surgery
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    • v.31 no.11
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    • pp.1043-1048
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    • 1998
  • Background: As coronary arterial disease is increasing, we evaluated the patients who underwent CABG(Coronary Artery Bypass Grafting) and thus report the early results and risk factors related to mortality and morbidity. Materials and methods: Between July 1996 and February 1998, 42 patients underwent CABG. We analyzed age, sex, preoperative ejection fraction, Canadian heart classification, prevalence factors of CAD(Coronary Artery Disease), angiographic findings, graft vessel numbers, IMA(Internal Mallary Artery) use, ECC* (extracorporeal circulation) time and morbidity. We also evaluated the mortality rate and the causes of death. Results: Complication was developed at 17cases. The average age of the complication group was 61±11.9 years and that of the noncomplication group was 51±10.5 years(p=0.004). ECC time was 198±42.5(min) in the complication group and 158±47.4(min) in the noncomplication group(p=0.008). The other factors had no correlation to the morbidity, statistically. The average follow up duration was 12.5 months and all the patients were alive except for the 2 expired cases. The mortality rate was 4.7%, among which one patient who underwent CABG with aortic valve replacement died due to multiorgan failure and the other died due to sepsis with pneumonia and wound infection. Conclusions: We conclude that the risk factors related to morbidity were age and ECC time, and that there were no correlations between other factors and morbidity.

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Analysis of Risk Factors in Coronary Artery Bypass Surgery (관동맥우회술의 위험인자 분석)

  • 정태은;한승세
    • Journal of Chest Surgery
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    • v.31 no.11
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    • pp.1049-1055
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    • 1998
  • Background: Coronary artery bypass surgery is an important treatment for ischemic heart disease. Recently operative mortality and morbidity has decreased, however further improvement is necessary. Materials and methods: This study was designed to evaluate the risk of operative mortality and morbidity by retrospective method. From 1992 to 1997, eighty six patients underwent coronary artery bypass surgery. There were 61 males and 25 females aged 36~74 years(mean, 58.6). Fourteen patients(16%) had previous PTCA or stent insertion, 41 patients(48%) had unstable angina, and 45 patients(52%) had three vessel disease. Patients with low LV ejection fraction(<35%) were 7 cases and urgent or emergent operation were 10 cases. There were 6 cases of combined surgery which were mitral valve replacement(2 cases), aortic valve replacement(2 cases), ASD repair(1 case), and VSD repair(1 case). Average number of distal anastomosis was 3.5 per patient and average aortic cross clamp time was 115±38.3min. Preoperative risk factors were defined as follows: female, old age(>70 years), low body surface area(<1.5M2), PTCA or stent insertion history, hypercholesterolemia, smoking, hypertension, DM, COPD, urgent or emergent operation, left main disease, low LV ejection fraction(<35%), and combined surgery. Results: Operative mortality was 7cases(8%). As a postoperative morbidity, perioperative myocardial infarction was 6 cases, cerebrovascular accident 6 cases, reoperation for bleeding 5 cases, acute renal failure 4 cases, gastrointestinal complication 3 cases, and mediastinitis 3 cases. In the evaluation of operative risk factors, low body surface area, DM and low LV ejection fraction were found to be predictive risk factors of postoperative morbidity(p<0.05), and low ejection fraction was especially a risk factor of hospital mortality(p<0.05). Conclusions: In this study, low body surface area, DM and low LV ejection fraction were risk factors of postoperative morbidity and low ejection fraction was a risk factor of hospital mortality.

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Scapular Free Flap (유리 견갑 피판 이식술)

  • Chung, Duke-Whan;Han, Chung-Soo;Yim, Chang-Moo
    • Archives of Reconstructive Microsurgery
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    • v.5 no.1
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    • pp.24-34
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    • 1996
  • There are many kinds of free flaps for management of extensive soft tissue defect of extremities in orthopaedic field. Free vascularized scapular flap is one of the most useful and relatively easy to application. This flap has been utilize clinically from early eighties by many microsurgical pioneers. Authors performed 102 cases of this flap from 1984 to 1995. We have to consider about the surgical anatomy of the flap, technique of the donor harvesting procedures, vascular varieties and anatomical abnormalities and success rate and the weak points of the procedure. This flap nourished by cutaneous branches from circumflex scapular vessels emerges from the lateral aspect of the subscapular artery 2.5-5cm from its lateral origin passing through the triangular space(bounded by subscapularis, teres minor, teres major, long head of triceps). The terminal cutaneous branch runs posteriorly around the lateral border of the scapular and divided into two major branches, those transeverse horizontally and obliquely to the fascial plane of overlying skin of the scapular body. We can utilize these arteries for scapular and parascapular flap. The vascular pedicle ranged from 5 to 10 cm long depends on the dissection, usually two venae comitantes accompanied circumflex scapular artery and its major branches. The diameter of the circumflex scapular artery is more than 1mm in adult, rare vascular variation. Surgical techniques : The scapular flap can be dissected conveniently with prone or lateral decubitus position, prone position is more easier in my experience. There are two kinds of surgical approaches, most of the surgeon prefer elevation of the flap from its outer border towards its base which known easier and quicker, but I prefer elevation of the flap from its outer border because of the lowering the possibilities of damage to vasculature in the flap itself which runs just underneath the subcutaneous tissue of the flap and provide more quicker elevation of the flap with blunt finger dissection after secure pedicle dissection and confirmed the course from the base of the pedicle. There are minimal donor site morbidity with direct skin closure if the flap size is not so larger than 10cm width. This flap has versatility in the design of the flap shape and size, if we need more longer and larger one, we can use parascapular flap or both. Even more, the flap can be used with latissimus dorsi musculocutaneous flap and serratus anterior flap which have common vascular pedicle from subscapular artery, some instance can combined with osteocutaneous flap if we include the lateral border of the scapular bone or parts of the ribs with serratus anterior. The most important shortcoming of the scapular free flap is non sensating, there are no reasonable sensory nerves to the flap to anastomose with recipient site nerve. Results : Among our 102 cases, overall success rate was 89%, most of the causes of the failure was recipient site vascular problems such as damaged recipient arterial conditions, and there were two cases of vascular anomalies in our series. Patients ages from 3 years old to 62 years old. Six cases of combined flap with latissimus dorsi, 4 cases of osteocutaneous flap for bone reconstruction, 62 parascapular flap was performed - we prefer parascapular flap to scapular. Statistical analysis of the size of the flap has less meaningful because of the flap has great versatility in size. In the length of the pedicle depends on the recipient site condition, we can adjust the pedicle length. The longest vascular pedicle was 14 cm in length from the axillary artery to the enter point cutaneous tissue. In conclusion, scapular free flap is one of the most useful modalities to manage the large intractable soft tissue defect. It has almost constant vascular pedicle with rare anatomical variation, easy to dissect great versatility in size and shape, low donor morbidity, thin and hairless skin.

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Analysis of Acute Kidney Injury in Pediatric Patients with Stem Cell Transplantation (소아에서 조혈모세포이식 후 급성 신질환의 분석)

  • Kim, Sae-Yoon;Choi, Jung-Youn;Ha, Jeong-Ok;Park, Yong-Hoon
    • Childhood Kidney Diseases
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    • v.13 no.2
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    • pp.130-137
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    • 2009
  • Purpose : Stem cell transplantation (SCT) has gained worldwide acceptance as a treatment for hematologic disorders. This study was performed to evaluate the clinical characteristics and outcomes of the acute kidney injury after SCT in children. Methods : The records of 53 patients who were treated with SCT at the pediatric department of Yeungnam University Hospital between January, 1996 and April, 2009 were used as subjects. Their were divided into two groups ; 'Early renal insufficiency' (ERI, n=18) and 'Non-early renal insufficiency' (NERI, n=35). ERI had greater than 25% of drop in GFR after SCT. Results: Total 53 patients were analyzed. In cord blood SCT (n=11), ERI was 4 (36.4%) and NERI was 7 (63.6%). In bone marrow SCT (n=16), ERI was 8 (50.0%) and NERI was 8 (50.5%). In autologous peripheral blood SCT (n=26), ERI was 6 (23.1%) and NERI was 20 (76.9%). There is no difference in both groups according to kinds of SCT. GVHD was developed in 22 patients, and there is no difference in each group. Twenty two of 53 patients died. ERI was 12 (66.7%) and NERI was 10 (28.6%). Acute renal failure is most important cause of the deaths. Conclusion : Out of 53 pediatric patients who were treated with SCT, 18 patients had greater than 25% of drop in GFR. There is no difference in both groups according to kinds of SCT. GVHD was found in 22 patients and there is no relation between GVHD development and acute kideney injury.

The Role of Intra-Aortic Balloon Pump in Coronary Artery Bypass Surgery (관상동맥 우회술에서의 대동맥내 풍선 펌프의 역할)

  • 박성식;김기봉
    • Journal of Chest Surgery
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    • v.30 no.3
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    • pp.282-286
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    • 1997
  • In the era of coronary artery bypass grafting, the intraaortic balloon pump (IABP) is more widely used and its indication has been ex anded. We perf'orbed retrospective clinical analysis on the patients who have received IABP pre andfor postoperatively during the course of CABG. From January 1981 to June 1995, total 322 patients have received CABG at the Seoul National University Hospital and among them 50 patients (15.5%) were supported by IABP during the course of the operation. The mean age at the time. of the operation was 57.2 years (39∼ 75 years) and the male to female ratio was 33 : 17. The preoperative diagnosis was unstable angina in 33 (66%), stable angina in 7 (14%) and postinfarct angina in 8 patients(16%). As for the indications of the IABP, there were 13 cases(26%) with left main disease, 13 (26%) with class IV angina, 12 (24%) with difficulty in CPB weaning, 6 (12%) with postinfarct angina and 3 (6%) with severe LV dysfunction. In the remaining 3 cases, one patient was operated on after PTCA failure in emergency basis, another was a patient with AMI, and the other was one who had postoperative low c rdiac output syndrome. All IABPS were introduced via femoral artery and among them 45 cases (90%) percutaneously. The mean postoperative assist time was 22.3 hours (0.5 ∼ 168 hours) and IABP could be removed within 48 hours in most of them (44150). The operative mortality was 6.1% (3 cases) and postoperative morbidity was only one with lower extremity ischemia. The more general application of the IABP during the course of the CABG ,especially in patients with high preoperative risk factors or difficulty in CPB weaning is a good measure of protecting and recovering myocardial function with minimal risk.

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The Short Term and Intermediate Term Results of using a T-tube in Patients with Tracheal Stenosis (기관 협착 환자에서의 T-튜브의 중단기 결과)

  • Sa, Young Jo;Moon, Seok-Whan;Kim, Young-Du;Jin, Ung;Park, Jae-Kil;Kim, Jae Jun;Kim, Chi-Kyung;Jo, Keon Hyon;Park, Chan Beom;Yim, Hyeon Woo
    • Journal of Chest Surgery
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    • v.42 no.1
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    • pp.63-71
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    • 2009
  • Background: The treatment of tracheal stenosis includes less invasive bronchoscopic intervention and more invasive segmental resection & anastomosis. Depending on the patient's clinical features, sometimes all these methods are inappropriate. Silicone T-tube stenting has recently been used as an alternative, safe management of tracheal stenosis. We studied the short term and Intermediate term results of using T-tubes in patients with tracheal stenosis, and this tracheal stenosis was caused by various underlying diseases. Material and Method: We retrospectively reviewed 57 patients with tracheal stenosis and who were treated with T-tubes between Jan 1997 and Apr 2007. Based on the patient's medical records and the imaging studies, we evaluated the clinical findings and status of T-tube removal. Result: There was no T-tube related morbidity or mortality in this series. On follow-up, one patient underwent sleeve resection and end-to-end anastomosis. The T-tube could be successfully removed from 13 patients (13/57, 22.8%) without additional interventions. For another four patients, a T-tube was again inserted after removal of the first T-tube due to tracheomalacia or recurrent stenosis. Four patients died of underlying disease and cancer. The patients' gender and previous tracheostomy significantly affected T-tube removal. By contrast, multiple logistic regression analysis identified gender as a predictor of successfully removing a T-tube. Gender (p=0.033) and previous tracheostomy (p=0.036) were the two factors for success or failure of T-tube removal. Conclusion: A T-tube provided reliable patency of a stenotic airway that was caused by any etiology. We have proven that using a T-tube is safe and effective therapy for patients with tracheal stenosis for the short term or the intermediate term.

Arthroscopic UU-Tension Band Suture for Rotator Cuff Tear above 4 cm - Comparative Study with Simple Suture - (큰 크기의 회전근 개 파열에서 UU-Tension Band Suture를 이용한 관절경 감시하의 봉합술 - 단순 봉합술과의 비교 -)

  • Ko, Sang-Hun;Lee, Chae-Chil;Shin, Seung-Myeong;Kim, Sang Woo;Cho, Bum-Keun
    • Clinics in Shoulder and Elbow
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    • v.15 no.2
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    • pp.99-108
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    • 2012
  • Purpose: To evaluate the clinical results of arthroscopic repair with UU-Tension Band suture for full thickness rotator cuff tear above 4 cm sized. Materials and Methods: From January 2006 to October 2011, in 71 full thickness tears above 4 cm sized which is possible to arthroscopic repair to medial margin of greater tuberosity. The group I is 71 patients which is arthroscopic repair with UU-Tension Band suture, and the group II is 20 cases which is arthroscopic repair with simple suture. Both groups were compared with a VAS score for pain, Activity of Daily Living, UCLA score, KSS score in pre operation, 7 months, 1 year and last follow-up. Statistical analysis was performed by student t test and paired t est. Mean age was 63.2 (52~80) year old, mean follow-up was 38.4 (13~62) months. Results: The VAS scores for pain decreased from 8.1 at preoperative period to 1.6 at postoperative last follow-up period in group I (p<0.05), the score decreased from 7.6 at preoperative period to 1.8 postoperative last follow-up period in group II (p<0.05). The significant difference was not noted between two groups (p<0.05). Mean ADL scores increased from 12.5 at preoperative period to 29.0 post operative last follow-up period in group I (p<0.05), the score increased from 11.3 in pre op to 27.5 post-operative last follow-up in group II (p<0.05). The significant difference was not noted between two groups (p<0.05). The UCLA score increased from 12.9 at preoperative period to 28.7 postoperative last follow-up period in group I (p<0.05), the score increased from 13.8 at preoperative period to 30.1 postoperative last follow-up period in group II (p<0.05). The significant difference was not noted between two groups (p<0.05). In comparing of retear which was checked by MRI and ultrasound evaluated at postoperative period 7 months (mean: 27.5 weeks), the retears were 28% in the group I, and 11 shoulders out of 20 shoulders in the group II. The significant differences were noted between two groups (p<0.05). Conclusion: Arthroscopic repair with UU-Tension Band suture and simple suture for full thickness rotator cuff tear above 4 cm sized were not different clinical result between both groups. However, the significant differences were noted in point of failure rate between both groups.

Clinical Study of Acute Pyogenic Osteomyelitis in Children (소아 급성 화농성 골수염의 임상적 고찰)

  • Park, Ji Sook;Yeom, Jeong Suk;Hwang, Sun Chul;Park, Eun Sil;Seo, Ji Hyun;Lim, Jae Young;Park, Chan Hoo;Woo, Hyang Ok;Youn, Hee Shang
    • Clinical and Experimental Pediatrics
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    • v.48 no.7
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    • pp.731-736
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    • 2005
  • Purpose : Acute pyogenic osteomyelitis is uncommon in children. Delayed diagnosis and inappropriate treatment are leading to growth failure and deformation. We review the clinical manifestations and treatment of acute osteomyelitis in children according to age. Methods : A retrospective analysis was made of 32 patients who underwent antibiotic management or operation between Aug 1989 and Dec 2003 for acute pyogenic osteomyelitis in age from 0 to 15 years old. Results : The study group was composed of 21 boys and 11 girls. The subjects were divided into four groups according to age : 0-1 yr(n=6), 1-5 yr(n=11), 6-10 yr(n=8), and 11-15 yr(n=7). Nineteen cases were diagnosed in Winter. Femur was the most common infected site(37.5%). There were no predisposing factor in 17 patients, and 7 of 15 patients had trauma history. Sepsis was important predisposing factor in neonates. The chief complaints were pain, swelling and fever. S. aureus(61%) is the most common organism. Twenty-nine patients were treated with operation and concomitant antibiotics. Two cases had sequelae in follow-up period : One is avascular necrosis of femur and the other is discrepancy of leg length. Conclusion : In our review, because of poor prognosis in septic neonates, we recommend to treat actively neonatal sepsis and prevent or detect osteomyelitis early. Because most of patients were diagnosed and treated in orthopedic surgery, the rate of operation was too high. So, protocol for further evaluation and management of acute osteomyelitis in pediatric patients were needed.

A Study on the Improvement Plan through Current Status of Historical Park in Seoul (서울시 역사공원의 현황 고찰을 통한 개선 방안 도출)

  • Ko, Young-Kwon;So, Hyun-Su
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.34 no.1
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    • pp.107-117
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    • 2016
  • In this study, six historical parks in Seoul is analyzed. Based on the analysis, the representative values of the historical parks in Seoul draw three criteria such as historicity, educational attributes, and sociality, and also the type of historic and cultural resources, spatial functions and arrangements, circulation and accessibility, and the type and usage of introduced facilities. Consequently the current status and improvement plan is suggested as follows. First, cultural assets oriented historical parks such as Sayuksin Bongeun and Seonnongdan historical Park focus on the management based on the preservation of historic and cultural resources. Non designated cultural heritages oriented historic parks such as Shingye Yanghwajin Itaewon-bugundang historic park should focus on the usages the symbolize and commemorate historic and cultural resources. Second, Careful attitudes on the historicity of the park are needed in the mixed type of historic and cultural resources that determine the identity such as Yanghwajin Itaewon-bugundang historic park. Third, the rate of facilities in Bongeun and Shingye historical park is increased due to the renovation of religion facilities, rather than the neighborhood parks. The autonomy of regulations that does not have the limits of the area of park facilities weaken the publicity of the historical parks. Fourth, Shingye historical park suggest changing its name into Danggogae martyrs' shrine historical park. because its historic and cultural resources are included as the historic park is named. Fifth, the current problems such as numerous uncontrolled entrances, mixed uses in circulation, and accessible failure due to the closure are recognized. Therefore, the entrances and circulations should be articulated clearly in order to increase opportunities of experience for visitors in the historic and cultural resources, and also neighborhood facility should be suitably divided. Sixth, the park facilities in the neighborhood parks are introduced equally in Seoul historical parks. The uses and arrangements that considered the circumstance of the historical parks should be determined in the cultural facilities such as outdoor music hall and sporting facilities. Seventh, historic facilities that named historic hall, culture hall, memorial hall, and promotion hall in the historic parks are utilized for convenience and religion facilities. Institutional framework should be examined to keep publicity in the historic parks by spatial privatization of the specific group.