• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.675-684
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• 2010

The reinforced concrete members are designed to fail in flexural to lead ductile fracture. In the building structures, the failure is typically imposed on beams to prevent damages in columns. However, progression of plastic collapse mechanism may ultimately develop, a plastic hinge at the bottem end of the first floor column, which then can be subjected to shear or bond finally due to large axial force and small shear span-to-depth ratio. In this study, 10 RC column specimens failed in shear after flexural yielding was investigated to determine the factors affecting the plastic hinge length. The findings of this study showed that the most effective factor affecting the plastic hinge length was an axial force. As an axial force increase, an axial strain and a ductility ratio were decreased obviously. The test also shows the observed plastic hinge length was about 0.8~1.2d and the this result has difference compared with forward research.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.247-256
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• 2013

The carbonate sands of the Sabkha layer in the Middle East have very low shear strength. Therefore, instant settlement and time-dependent secondary settlement occur when inner voids are exposed, as in the case of particle crushing. We analyzed settlement of the Sabkha layer under a large-scale foundation by hydrotesting, and compared the field test results with the results of laboratory tests. With ongoing particle crushing, we observed the following stress-strain behaviors: strain-hardening (Sabkha GL-1.5 m), strain-perfect (Sabkha GL-7.0 m), and strain-softening (Sabkha GL-7.5 m). General shear failure occurred most frequently in dense sand and firm ground. Although the stress-strain behavior of Sabkha layer carbonate sand that of strain-softening, the particle crushing strength was low compared with the strain-hardening and strain-perfect behaviors. The stress-strain behaviors differ between carbonate sand and quartz sand. If the relative density of quartz sand is increased, the shear strength is also increased. Continuous secondary compression settlement occurred during the hydrotests, after the dissipation of porewater pressure. Particle crushing strength is relatively low in the Sabkha layer and its stress-strain behavior is strain-softening or strain-perfect. The particle crushing effect is dominant factor affecting foundation settlement in the Sabkha layer.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.723-730
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• 2008

Due to the higher ratio of live load to total loads of railway bridges, the accumulated damage by cyclic fatigue is significant. Moreover, it is highly possible that the initiated crack grows faster than that of highway bridges. Therefore, it is strongly needed to assess the safety for the accumulated damage analytically. The initiation and growth of fatigue-crack are related with the stress range, number of cycles, and the stiffness of the structural system. The stiffness of the structural system includes uncertainties of the planning, design, construction and maintenance, which varies as time goes. In this study, the authors developed the design and risk assessment techniques based on the reliability theories considering the uncertainties in load and resistance. For the probabilistic risk assessment of crack growth and the remaining life of the structures by the cyclic load of railway and subway bridges, response surface method (RSM) combined with first order second moment method were used. For composing limit state function, the stress range, stress intensity factor and the remaining life were selected as input important random variables to the RSM program. The probabilities of failure and the reliability indices of fatigue life for the considered specimen under cyclic loads were evaluated and discussed.

• Journal of Trauma and Injury
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• v.25 no.4
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• pp.247-253
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• 2012

Purpose: Hemorrhage is a main cause of death in trauma patients. The goal of this study is to describe the characteristics of trauma patients with massive bleeding and to evaluate the prognostic factors concerning their survival. Methods: This study was performed retrospectively and included trauma patients with massive bleeding who had been treated from March 2007 to August 2012. The inclusion criterion was patients who received more than 10 U of packed red blood cells within the first 24 hours after visiting the emergency department. Based on their medical records, we collected data in terms of demographic findings, mechanisms of injury, initial clinical and laboratory findings, methods for hemostasis (emergency surgery and/or angioembolization), transfusion, injury severity score (ISS), revised trauma score (RTS) and trauma and injury severity score (TRISS). We used the Mann-Whitney U test and Fisher's exact test to compare the variables between the patients that survived and those that did not. We performed a logistic regression analysis with the significant variables from the univariate test. Results: Thirty-two(32) patients were enrolled. The main mechanisms of injury were falls and motor vehicle accidents. The mean transfusion amount of packed red blood cells (PRBC) was 17.4 U. The mean elapsed time for the first hemostasis (surgery or embolization) was 3.5 hours. The initial technical success rates were 83.3%(15/18) in angioembolization and 66.7%(8/12) in surgery. The overall mortality rate was 34.4%(11/32). The causes of death were bleeding, brain swelling and multiple organ failure. The ISS(25.5 vs 46.3, p=0.000), TRISS(73.6 vs 45.1, p=0.034) and base excess(<-12 mmol/L, p=0.020) were significantly different between the patients who survived and those who did not. Conclusion: The ISS was a prognostic factor for trauma patients with massive bleeding.

• Radiation Oncology Journal
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• v.31 no.3
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• pp.138-146
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• 2013

Purpose: To analyze the results of locoregional and systemic therapy in the breast cancer patients with locoregional recurrence (LRR) after mastectomy. Materials and Methods: Seventy-one patients who received radiotherapy for isolated LRR after mastectomy between January 1999 and December 2009 were retrospectively reviewed. Among the 71 patients, 59 (83.1%) underwent wide excision and radiotherapy and 12 (16.9%) received radiotherapy alone. Adjuvant hormonal therapy was given to 45 patients (63.4%). Oncologic outcomes including locoregional recurrence-free survival, disease-free survival (DFS), and overall survival (OS) and prognostic factors were analyzed. Results: Median follow-up time was 49.2 months. Of the 71 patients, 5 (7%) experienced second isolated LRR, and 40 (56%) underwent distant metastasis (DM). The median DFS was 35.6 months, and the 3- and 5-year DFS were 49.1% and 28.6%, respectively. The median OS was 86.7 months, and the 5-year OS was 62.3%. Patients who received hormone therapy together showed better 5-year DFS and OS than the patients treated with locoregional therapy only (31.6% vs. 22.1%, p = 0.036; 66.5% vs. 55.2%, p = 0.022). In multivariate analysis, higher N stage at recurrence was a significant prognostic factor for DFS and OS. Disease free interval (${\leq}30$ months vs. >30 months) from mastectomy to LRR was also significant for OS. The patients who received hormone therapy showed superior DFS and showed trend to better OS. Conclusion: DM was a major pattern of failure after the treatment of LRR after mastectomy. The role of systemic treatment for LRR after mastectomy should be investigated at prospective trials.

• The Korean Society of Law and Medicine
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• v.15 no.1
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• pp.263-302
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• 2014

The court handed down meaningful rulings related to medical sectors in 2013. This paper presents the ruling that the care workers could be the performance assistants of the care-giving service although the duties of care worker are not included in the liability stipulated in the medical contract signed with the hospital for reason of clear distinction of duties between care workers and nurses within the hospital in connection with the contract which was entered into between the hospital and patients. In relation to negligence and causal relationship, the court recognized medical negligence associated with the failure to detect the brain tumor due to the negligent interpretation of MRI findings while rejecting the causal relationship with consequential cerebral hemorrhage. The court also recognized negligence based on the observation on the grounds of inadequate medical records in a case involving the hypoxic brain damage caused during the cosmetic surgery. In terms of the scope of compensation for damages, this paper presents the ruling that the compensation should be estimated based on causal relationship only in case the breach of the 'obligation of explanation' is recognized, however rejecting the reparation for de factor property damages in the form of compensation, and the ruling that the lawsuit could be instituted in case that the damages exceeded the agreed scope despite the agreement that the hospital would not be held responsible for any aftereffects of surgery from the standpoint of lawsuit, along with the ruling that recognized the daily net income by reflecting the unique circumstances faced by individual students of Korean National Police University and artists of Western painting. Many rulings were handed down with respect to medical certificate, prescription, etc., in 2013. This paper introduced the ruling which mentioned the scope of medical certificate, the ruling that related to whether the diagnosis over the phone at the issuance of prescription could constitute the direct diagnosis of patient, along with the ruling that required the medical certificate to be generated in the name of doctor who diagnosed the patients, and the ruling which proclaimed that it would constitute the breach of Medical Act if the prescription was issued to the patients who were not diagnosed. Moreover, this paper also introduced the ruling that related to whether the National Health Insurance Service could make claim to the hospitals for the reimbursement of the health insurance money paid to pharmacies based on the prescription in the event that the hospitals provided prescription of drugs to outpatients in violation of the laws and regulations.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1190-1196
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• 1997

Between July 1994 and August 1995, 78 patients underwent coronary artery bypass graft at Seoul National University Hospital. Coronary angiogram was performed one year after coronary artery bypass graft in 49 patients(62.8%) for evaluation of the graft patency and analysis of the risk factors for graft occlusion. The patency rates of both the internal mammary artery and the radial artery grafts were 100% , although three internal mammary artery grafts(5.0%) were narrowed(string sign). And that of the saphenous vein grafts were 85.2%. Multivariate analysis for the preoperative, operative, and postoperative factors was done between the widely patent and the narrowed internal mammary artery graft groups, and between the patent and the occluded saphenous vein graft groups by the general linear models procedure. Patient's age($\geq$60 years), postoperative intraaortic balloon pump insertion, bleeding, and acute renal failure were found to be the significant risk factors for internal mammary artery graft narrowing, and coronary artery size(< 1.5 mm) was the significant risk factor for the saphenous vein graft occlusion (p<0.05) . This study confirms that the arterial graft is superior to the vein graft at one-year patency rate, and suggests the risk factors for graft occlusion during the first postoperative year. Knowledge of this study may provide a basis for estimating the risk factors for graft occlusion, and thereby modifying surgical strategy and postoperative surveillance.

• Journal of Chest Surgery
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• v.45 no.2
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• pp.110-115
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• 2012

Background: Pneumonectomy remains the ultimate curative treatment modality for destroyed lung caused by tuberculosis despite multiple risks involved in the procedure. We retrospectively evaluated patients who underwent pneumonectomy for treatment of sequelae of pulmonary tuberculosis to determine the risk factors of early and long-term outcomes. Materials and Methods: Between January 1980 and December 2008, pneumonectomy or pleuropneumonectomy was performed in 73 consecutive patients with destroyed lung caused by tuberculosis. There were 48 patients with empyema (12 with bronchopleural fistula [BPF]), 11 with aspergilloma and 7 with multidrug resistant tuberculosis. Results: There were 5 operative mortalities (6.8%). One patient had intraoperative uncontrolled arrhythmia, one had a postoperative cardiac arrest, and three had postoperative respiratory failure. A total of 29 patients (39.7%) suffered from postoperative complications. Twelve patients (16.7%) were found to have postpneumonectomy empyema (PPE), 4 patients had wound infections (5.6%), and 7 patients required re-exploration due to postoperative bleeding (9.7%). The prevalence of PPE increased in patients with preoperative empyema (p=0.019). There were five patients with postoperative BPF, four of which occurred in right-side operation. The only risk factor for BPF was the right-side operation (p=0.023). The 5- and 10-year survival rates were 88.9% and 76.2%, respectively. The risk factors for late deaths were old age (${\geq}50$ years, p=0.02) and low predicted postoperative forced expiratory volume in one second (FEV1) (< 1.2 L, p=0.02). Conclusion: Although PPE increases in patients with preoperative empyema and postoperative BPF increases in right-side operation, the mortality rates and long-term survival rates were found to be satisfactory. However, the follow-up care for patients with low predicted postoperative FEV1 should continue for prevention and early detection of pulmonary complication related to impaired pulmonary function.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.57-61
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• 2008

Purpose: $^{18}F$-FDG PET is to evaluate the tumor using glucose metabolism. Blood Glucose Level (BGL) is important factor that affects on a result of examination. But it often appears the distort result on diabetic patient due to a failure of BGL control. The aim of this study is to make a effective guideline for diabetic patient prescribed $^{18}F$-FDG PET and improve accuracy and reliability of examination. Materials and methods: A subject of study is 69 diabetic patients and divided them into 3 groups; 1) BGL is less than 120 mg/dl & performed PET, 2) BGL is over than 120 mg/dl & performed PET, 3) BGL is over than 120 mg/dl & not performed PET. And we investigated the type of diabetic medications and the time of dosage, whether they have meal or not. And we analyzed SUV of liver and mediastinum to recognize the effect of BGL on PET images. Results: As a methods to diabetic control, Amalyl showed high percentage of 27.5% in oral medication and Humulin R showed 14.5% in insulin. Their peak time was 2-3 hrs, 2-4 hrs and duration time was 24 hrs, 5-7 hrs. The number of that had a breakfast was 16, 7 mens (43.8%) couldn't perform PET as over 120 mg/dl and 5 mens (31.3%) performed PET as less than 120 mg/dl after they took a medication. When we set the SUV of normal for 1.5-2.0, 1.0-1.5 on liver and mediastinum, the percentage out of the range was 31.8%, 52.9%, 62.5% in 120-139 mg/dl, 140-159 mg/dl, 160-200 mg/dl respectively. Conclusions: We completed standardized guideline for diabetic patients. As a result of this study, improved customer satisfaction and increased economic benefits. It is expect to be a effective model in other PET centers.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.187-187
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• 2009

Opening of fractures induced by shear dilation or normal deformation can be a significant source of fracture permeability change in fractured rock, which is important for the performance assessment of geological repositories for spent nuclear fuel. As the repository generates heat and later cools the fluid-carrying ability of the rocks becomes a dynamic variable during the lifespan of the repository. Heating causes expansion of the rock close to the repository and, at the same time, contraction close to the surface. During the cooling phase of the repository, the opposite takes place. Heating and cooling together with the, virgin stress can induce shear dilation of fractures and deformation zones and change the flow field around the repository. The objectives of this work are to examine the contribution of thermal stress to the shear slip of fracture in mid- and far-field around a KBS-3 type of repository and to investigate the effect of evolution of stress on the rock mass permeability. In the first part of this study, zones of fracture shear slip were examined by conducting a three-dimensional, thermo-mechanical analysis of a spent fuel repository model in the size of 2 km $\times$ 2 km $\times$ 800 m. Stress evolutions of importance for fracture shear slip are: (1) comparatively high horizontal compressive thermal stress at the repository level, (2) generation of vertical tensile thermal stress right above the repository, (3) horizontal tensile stress near the surface, which can induce tensile failure, and generation of shear stresses at the comers of the repository. In the second part of the study, fracture data from Forsmark, Sweden is used to establish fracture network models (DFN). Stress paths obtained from the thermo-mechanical analysis were used as boundary conditions in DFN-DEM (Discrete Element Method) analysis of six DFN models at the repository level. Increases of permeability up to a factor of four were observed during thermal loading history and shear dilation of fractures was not recovered after cooling of the repository. An understanding of the stress path and potential areas of slip induced shear dilation and related permeability changes during the lifetime of a repository for spent nuclear fuel is of utmost importance for analysing long-term safety. The result of this study will assist in identifying critical areas around a repository where fracture shear slip is likely to develop. The presentation also includes a brief introduction to the ongoing site investigation on two candidate sites for geological repository in Sweden.