A Case of Symptomatic Tracheal Diverticulum and Surgical Resection as a Treatment Modality

Tracheal diverticulum is often diagnosed incidentally and, due to its rarity, there is no standard treatment. It is a benign entity, but has the potential to cause specific symptoms, such as chronic upper respiratory infection and chronic cough. Symptomatic tracheal diverticulum can be medically treated, but likelihood of recurrence is high. We report a case of surgical resection of symptomatic tracheal diverticulum to prevent recurrence.ope

Early Clinical Experience with Sutureless Aortic Valve Replacement for Severe Aortic Stenosis

Background: Sutureless aortic valve replacement (SU-AVR) has been developed as an alternative surgical treatment for patients with symptomatic severe aortic stenosis (AS). The aim of this study was to evaluate the clinical outcomes of SU-AVR through an assessment of hemodynamic performance and safety. Methods: From December 2014 to June 2016, a total of 12 consecutive patients with severe AS underwent SU-AVR. The endpoints were overall survival and valve-related complications (paravalvular leakage, valve thrombosis, migration, endocarditis, and permanent pacemaker implantation). The mean follow-up duration was 18.1±8.6 months. Results: The mean age of the patients was 77.1±5.8 years and their mean Society of Thoracic Surgeons score was 9.2±17.7. The mean cardiopulmonary bypass and aortic cross-clamp times were 94.5±37.3 minutes and 54.9±12.5 minutes, respectively. Follow-up echocardiography showed good prosthesis function with low transvalvular pressure gradients (mean, 13.9±8.6 mm Hg and peak, 27.2±15.0 mm Hg) at a mean of 9.9±4.2 months. No cases of primary paravalvular leakage, valve thrombosis, migration, or endocarditis were reported. A new permanent pacemaker was implanted in 1 patient (8.3%). The 1-year overall survival rate was 83.3%±10.8%. Conclusion: Our initial experience with SU-AVR demonstrated excellent early clinical outcomes with good hemodynamic results. However, there was a high incidence of permanent pacemaker implantation compared to the rate for conventional AVR, which is a problem that should be solved.ope

중학생의 혈액 순환에 대한 소집단 모델링 과정에서 나타나는 인지적 협력 이해

학위논문 (박사)-- 서울대학교 대학원 : 과학교육과(생물전공), 2014. 2. 김희백.Scientists generate, evaluate, and modify models to explain phenomena and communicate with others. Modeling is also significant in science education because it allows students to generate, evaluate, and modify the explanation of phenomena in terms of epistemic practice. In this study, the group modeling-based inquiry lessons about blood circulation were designed to develop middle school students modeling abilities through learning by cognitive collaboration. With these, this study aimed to understand the epistemic process through cognitive collaboration in group modeling-based learning. The study is consisted of following three parts. The study of Patterns of Group Model Development and Factors Influencing Reasoning Process in Collaborative Modeling aimed to explore the patterns of model development and the factors that led to differences in reasoning among several groups developing one-way circulation models. Fourteen students in gifted science education center participated in this study. Participants engaged in group modeling activities about one-way blood flow in the heart. After analyzing discourse, the patterns of model development were identified as the unchanged, the added, and the elaborated. The patterns of model development were decided by interaction within group members. The high-level reasoning process necessary for strong scientific argument was found in the elaborated pattern. The analogy model activity and the cognitive conflict within groups were the factors that influenced high-level reasoning. Based on the finding from of the study of Patterns of Group Model Development and Factors Influencing Reasoning Process in Collaborative Modeling that shaped the critical role of evaluation for model development, the study of Epistemological Features and Model Qualities Depending on the Model Evaluation Levels aimed to explore epistemological features and model qualities depending on the model evaluation levels and to identify reasoning processes revealed in a high-level of model evaluation. 34 students in K middle school participated in three modeling-based lessons. The third lesson in which students drew diagrams of blood circulation as group model was chosen for analyzing the epistemological features and model qualities. The model evaluation levels were defined as Levels 1 to 4 based on the evaluation criteriathe higher levels reflected a greater depth of critical thought and metacognitive monitoring concerning the changeable nature of models and the explanatory nature of the model. At Level 4, students evaluated the explanatory nature of the model in terms of the processes and the mechanisms of the phenomena depicted. This evaluation was based on the epistemological belief of knowing that the model constructed within a group should be evaluated for further development and alteration. In the highest level of model evaluation, reasoning processes through cognitive collaboration were well-expressed by statements concerning monitoring ones own and/or others understanding. Based on this finding of the study of Epistemological Features and Model Qualities Depending on the Model Evaluation Levels, the study of Expression of Statements of the Deep Learning Approach and Cognitive Collaboration in Group modeling aimed to identify the differences of expression of statements of deep learning approach (SD: Statements of the deep learning approach) according to the features of group modeling activities and to explore cognitive collaboration during group modeling processes focusing on students SD. Four students among participants in the study of Epistemological Features and Model Qualities Depending on the Model Evaluation Levels were selected for case study. They engaged in three modeling-based lessons about blood circulation. The dominant SD categories found in each lesson varied because of the different properties relevant to the modeling. Individual SD influenced collaborative modeling through the deep reasoning process. Cognitive collaboration involved cognitive scaffolding and critical monitoring: cognitive scaffolding contributed to the generation and elaboration of the model, whereas critical monitoring contributed to the evaluation and modification of the model. These findings could contribute to understand how cognitive collaboration occurs during group modeling and have significant implications on how to design and implement group modeling lessons where students experience authentic epistemic practice in science classroom.List of Tables viii List of Figures x CHAPTER Ⅰ. INTRODUCTION 1 1. Significance of the Study 1 2. Research Questions 8 3. Research Overview 10 4. Definitions of Terms 13 Ⅱ. THEORETICAL BACKGROUNDS 17 1. Models and Modeling in Science Education 17 1.1. Models in Science Education 17 1.2. Modeling in Science Education 25 1.3. Collaborative Modeling 27 1.4. The Roles of Models and Modeling 32 2. Models and Modeling of Blood Circulation 35 3. Cognitive Reasoning in Modeling 40 3.1. Practical Epistemology Revealed in Model Evaluation 40 3.2. Argumentation in Modeling 45 4. The Approaches to Learning Science in Collaborative Modeling 48 Ⅲ. Patterns of Group Model Development and Factors Influencing Reasoning Process in Collaborative Modeling 54 1. Introduction 54 2. Methods 58 2.1. Participants 58 2.2. Context 59 3.3. Data Collection and Analysis 61 3. Results and Discussions 67 3.1. The Patterns of Group Model Development 67 3.1.1. The unchanged patterns 70 3.1.2. The added patterns 71 3.1.2. The elaborated patterns 74 3.2. Factors Influencing Reasoning Process in Group Modeling 79 3.2.1. The differences of reasoning process according to the task features of modeling activities 82 3.2.2. The reasoning processes influenced by cognitive conflict among group members 86 4. Conclusions and Implications 91 Ⅳ. Epistemological Features and Model Qualities Depending on the Model Evaluation Levels 95 1. Introduction 95 2. Methods 98 2.1. Participants 98 2.2. Context 100 3.3. Data Collection and Analysis 104 3. Results and Discussions 114 3.1. Epistemological Features and Model Qualities Depending on the Levels of Model Evaluation 115 3.1.1. The phase without model evaluation 115 3.1.2. The phase of model evaluation using authoritative sources 118 3.1.3. The phase of model evaluation using superficialcriteria 123 3.2. The Highest-Level Model Evaluation Process 126 3.2.1. Checking self-understanding: Raising questions 128 3.2.2. Monitoring others understanding: Emergence after expression of an incorrect concepts 133 4. Conclusions and Implications 139 Ⅴ. Expression of Statements of the Deep Learning Approach and Cognitive Collaboration in Group Modeling 145 1. Introduction 145 2. Methods 149 2.1. Participants 149 2.2. Task Characteristics of the Implemented Lessons 152 3.3. Data Collection and Analysis 157 3. Results and Discussions 162 3.1. Patterns of Statements of the Deep Learning Approach Expression in Each Lesson 162 3.2. Cognitive Collaboration and Model Development Influenced by Statements of the Deep Learning Approach 168 3.2.1. Cognitive scaffolding 168 3.2.2. Critical monitoring 180 4. Conclusions and Implications 185 Ⅵ. CONCLUSIONS AND IMPLICATIONS 191 1. Conclusions 191 2. Implications 194 References 198 Appendix 216 국문초록 224Docto

Validation of HAH model Using Non-linear Strain Path Experiments

MasterDuring sheet metal forming processes, the material undergoes quasi-linear and non-linear strain paths. A non-linear strain path causes large fluctuations in the hardening behavior of a material that produce phenomena such as the Bauschinger effect, the transient stage with high hardening rate or permanent softening. It is very important to capture these phenomena in the constitutive equations in order to conduct accurate sheet metal forming process simulations. Recently, the Homogeneous Anisotropic Hardening (HAH) model was proposed in MML to describe the hardening behavior of materials subjected to non-linear strain path. Unlike conventional kinematic hardening, in which the yield surface translates in stress space, the HAH model predicts the hardening behavior solely based on the distortion of the yield surface. To verify the validity of the HAH model, non-linear strain path experiments were conducted in this work. The first strain path, called pre-strain, was always uniaxial tension in the sheet transverse direction (90º from rolling direction). For the pre-strain, large tensile specimens were clamped in a suitable gripping system and deformed in order to produce a sufficiently large size area with a uniform strain distribution from which new specimens were machined. After these pre-strain tests, new specimens were subjected to different modes of deformation, namely, uniaxial tension in directions different from the transverse direction, simple shear and biaxial tests with different load ratios. The experimental results, the flow curves and the yield surfaces, were compared with those simulated by the HAH model. These comparisons allow the assessment of the accuracy and shortcomings model, which are very useful to improve the HAH formulation

북한 결핵관리 장애요인 분석 : 탈북 결핵환자·간병자·의사 면담자료를 중심으로

보건정책학과 보건정책관리전공/석사본 연구는 북한 결핵관리 장애요인을 파악하기 위해 탈북자 22명에 대한 면담자료를 분석한 질적 연구이다. 눈덩이 및 집충추출 방법으로 선정된 탈북 결핵환자(이하 결핵수진자) 9명, 탈북 결핵간병자 3명, 탈북 의사 10명의 면담 자료를 Cough to Cure Pathway를 활용하여 분석하고 북한 결핵관리의 장애요소를 파악하였다. 본 연구결과를 요약하면 다음과 같다. 1. 환자 및 지역사회 장애로 인식장애와 접근장애가 확인되었다. 인식장애를 결핵수진·간병자 12명을 대상으로 확인한 결과, 결핵 지식 부족, 지역사회 태도 부족이 나타났다. 결핵 지식 중 결핵 위험성(응답자 7명 중 5명 양호)과 감염성(응답자 10명 중 9명 양호) 지식은 양호하였으나, 6개월 치료기간(응답자 7명 중 4명 미인식), 결핵의 치료 가능성(응답자 4명 중 3명 미인식), 직접 복약확인 치료(응답자 8명 전원 미인식)에 대한 지식은 다소 낮은 수준으로 확인되었다. 지역사회 태도 관련하여 결핵환자에 대한 지역사회의 낙인과 중요한 진단 및 치료 영향요인으로 가족의 지지(7명)가 확인되었다. 이러한 지식과 태도에 영향을 끼칠 수 있는 요소로 호담당의사의 결핵 교육은 실시되지 않는다(6명)는 의견이 다수로 확인되었다. 접근장애로 각 방문지연 사유와 낮은 접근성, 의료 이용 불평등이 확인되었다. 의료기관 방문을 지연시키는 것으로 비용에 대한 부담감(5명), 사적시장 방문(4명), 공식의료에 대한 부정적 인식(3명), 민간의료 이용(2명)이 보고되었으며, 의료기관 방문 시 리/동 진료소(1명)보다 군급 병원(3명) 혹은 도급 병원(3명)에 방문 비중이 높았다. 이 밖에 이동거리 및 비용, 파송증이 북한 내 의료이용에 대한 접근성을 저하시키며, 사회 지위와 인맥에 따라 의료이용 불평등(7명)이 나타났다. 기타 취약집단 및 요인으로 군대 및 교화소와 같은 특수집단이 결핵관리에 취약하였으며 영양부족 영향이 크다고 보고되었다. 2. 보건의료체계 장애로 보건의료 서비스의 낮은 질 장애, 진단 장애, 치료 장애, 추구·종료 검사 장애가 각각 확인되었다. 북한 보건의료 서비스의 질적 장애로 의료 인적자원 및 서비스 제공 불충분, 대기시간 불편이 요인으로 나타났다. 특히 인적자원 분야는 경제난 이후 생계 지속을 위한 의료인 유출 및 의료인의 개인적 이익 추구경향 증가, 환자-의료인 의사소통 부족, 의료인 결핵 관리에 활동에 대한 인센티브 부족이 확인되었다. 진단 장애로 환자발견은 경제난 이후 능동적 환자발견이 실질적으로 중단되었으며, 환자가 증상을 느끼고 방문하여 진단 받는 수동적 환자발견 위주로 확인된다. 폐결핵의 주요 진단검사인 X-선 및 객담검사 중, X-선 검사(투시방식)는 비교적 이상 없이 지속되어 왔으나 객담검사는 경제난 시기 제한되었다가 외부지원을 통해 상당히 회복되었다. 치료 장애로 치료비, 결핵약, 서비스 장애가 확인되었다. 의료기관에서 비공식 비용을 1차로 납부하고 장마당에서 약제를 구입을 2차로 시행하는 현재 북한식 의약분업 구조와 영양보충비로 치료비는 부담이 된다. 결핵약은 북한 자체 생산역량이 부족하나 지속적 외부지원을 통해 표준약제에 대한 접근성이 향상되었다. 입원치료 환경이 열악하고 식사지원이 제한되어 치료에 어려움이 있고, 외래치료는 의료인이 지속적인 복약관리에 동기부여가 적어 환자들의 적극적인 태도가 요구된다. 국제적 결핵관리 관점에서 북한 결핵지원 의견 및 제3국에서의 결핵관리경험을 확인 결과, 북한이탈주민들은 북한에 대해 현재의 약제지원을 지속하는 동시에 영양관리, 진단장비 강화, 의료인력 지원이 필요하다고 제안하였으며, 다수의 탈북 결핵수진·간병자(6명)가 탈북 시 제3국에서 결핵을 치료한 경험이 확인되었다. 결핵은 남북한 공통의 문제로 각종 중재 및 통일 전 협력이 필수적인 분야이며 동시에 통일 계기로 이끌 수 있어 지속적 관심과 협력이 필요한 분야이다. 북한의 결핵은 보건안보 관점에서 국제사회와 남한의 지속적 공조를 통해 취약계층에 중재가 필요하다. 북한 결핵관리 장애요인에 대한 추가적인 양적연구와 남한에서도 본 연구와 같은 환자중심 관점의 결핵문제 파악을 위한 연구가 요구된다. The purpose of this qualitative study was to analyze the barriers for the management of tuberculosis in North Korea by reviewing the interviews with 22 North Korean defectors. Specifically, 9 patients with history of tuberculosis, 3 caregivers and 10 physicians were selected among the North Korean defectors through snowball and intensive sampling methods followed by the analysis using the Cough to Cure Pathway. The results of this study are as followings; 1. Barriers for recognition of the disease and access to care for patients and community were confirmed. As a result of reviewing the 9 patients and 3 caregivers, lack of knowledge and passive attitude for the disease were identified among patients and the community. Regarding the knowledge about tuberculosis, 5 subjects out of 12 were more or less aware of the dangers of the disease while 9 subjects out of 10 were acknowledging its infectious characteristics. In contrast, 4 subjects out of 7 were less aware of the amount of the time required for the treatment, 3 subjects out of 4 were little aware of the chance of being treated, and all subjects (8) knew that their diseases could be treated through medication. Moreover, the tuberculosis patients were found to be stigmatized in their community. Seven subjects reported that support from family was important. The majority (6 subjects) answered that the physicians in charge of their families had never educated them about the disease. Regarding the barriers to access care, problems such as delay in visit to the health facility, difficulties in receiving treatment, and inequality for availability of medical services were reported. Burden of the cost (5 subjects), utilization of the private clinic(4 subjects), negative perception for the public health service (3 subjects), utilization of the traditional folklore therapy (2 subjects), and etc were reported as The reasons for delay in visit to the health...ope

(An) evaluation of the analytic methods of ethylene oxide following pre-treatment

산업보건학과/석사[한글] OSHA method 50에 따라 HBr-coated charcoal tube를 사용하여 산화 에틸렌(ethylene oxide, EO)을 측정시 나타나는 문제점은 기기분석을 위한 전처리 방법의 절차가 복잡해서 분석상의 오차가 발생할 가능성이 높다는 것이다. 따라서 본 연구는 HBr-coated charcoal tube에 포집된 EO를 전처리 할 때, 용매 및 유도체화에 따른 탈착효율 및 정밀도를 비교평가하여 정확도와 정밀도가 높으면서도 분석절차가 간편한 방법을 제시하고자 하였다. 이를 위하여 OSHA method 30에서 제시한 benzene:CS2(99:1) 용매로 탈착한 시료와 OSHA method 50에서 제시하는 n,n-dimethylformamide(DMF)로 탈착한시료 및 DMF로 탈착후 2-bromoethylheptafluorobutyrate로 유도체화 시킨 시료의 검출한계(limit of detection, LOD), 통합변이계수(pooled coefficient of variation, pooled CV), 탈착효율(desorption efficiency, DE) 그리고 탈착 후 안정성(stability)을 비교하였다. 연구결과는 다음과 같다. 선형 회귀식에 의해 산출한 EO의 LOD는 benzene:CS2(99:1)로 탈착하였을 때 2.483ug/㎖이었고, DMF로 탈착한 분석결과는 1.919ug/㎖이었으며, DMF 탈착 후 유도체화 시킨 시료의 분석결과는 1.301ug/㎖으로 나타났다. EO 분석결과의 pooled CV는 benzene:CS2(99:1)용매로 탈착하였을 때 0.00503이었고, DMF로 탈착한 결과는 0.00329이었으며, DMF 탈착 후 유도체화 시킨 결과는 0.00514이었다. EO의 탈착효율은 benzene:CS2(99:1)용매로 탈착하였을 때 92.13%이었고, DMF로 탈착한 분석결과는 102.75%이었으며, DMF로 탈착 후 유도체화 시킨 결과는 96.47%이었다. EO의 탈착 후의 안정성은 benzene:CS2(99:1)용매로 탈착 후, 하루 지난 뒤의 분석결과는 당일 결과의 96.81%이었고, DMF로 탈착 후의 결과는 97.13%이었으며, DMF로 탈착하여 유도체화 시킨 분석 결과는 95.69%이었다. 이 값들은 OSHA method 50에서 제시하고 있는 5%미만의 감소기준에 모두 적합하였다. 결론적으로 HBr-coated charcoal tube에 포집된 EO 분석시에, DMF로 탈착한 후 바로 분석하는 것이 다른 방법에 비해 분석절차가 간편하면서도 정확도와 정밀도가 높은 분석방법인 것으로 나타났으며, 탈착 후 24시간동안 시료의 안정성도 확보 되었다. [영문] Following the OSHA method 50, problems occur when measuring the Ethylene oxide, EO, using a HBr-coated Charcoal tube. The problems are that for the machinery-analysis necessary for the pre-treatment process, the sample, after desorption, must go through more than 3 stages of analysis in order to create the EO inducing substance, 2-bromoethylheptafluorobutyrate, and must also be transferred more than twice into new vials. Through such complicated processes, it is highly possible for errors to occur during the analyzing process. As such, our lab, when handling the EO of the HBr-coated charcoal tube, compared and studied the efficiency and preciseness of the solvent and derivatives'' desorption in order to simplify the analyzing process while heightening precision and accuracy of the analyzing method. To achieve this, the desportion sample of the benzene:CS2(99:1) given by the OSHA method 30, the desportion sample of n,n-dimenthylfomamide(DMF) given by OSHA method 50, and the sample that was derivativized with 2-bromoethylheptafluorobutyrate after desorption by DMF were studied and compared for their limit of detection(LOD), pooled coefficient of variation(pooled CV), desorption efficiency(DE), and stability after desorption. The results were as follows: The EO''s LOD was 2.483ug/sample when using the solvent, benzene:CS2(99:1), and 1.919ug/sample after desorption using DMF. The result of the sample that passed DMF desorption and was derivativized was 1.301ug/sample. EO''s pooled CV was 0.00503 when using the solvent benzene:CS2(99:1), after desorption with DMF, the result was 0.00329, and the result of those derivativized by DMF desorption was 0.00514. EO''s DE using the solvent benzene:CS2(99:1) was 92.13%, after desorption with DMF, it was 102.75%, and the result of those studied after being derivativized by DMF desorption was 96.47%. EO''s stability for the sample with the solvent benzene:CS2(99:1), comparing result of next-day analysis to same-day was 96.81%, after desorption with DMF, it was 97.13%, and the result of those studied after being derivativized by DMF desorption was 95.69%. These results were in accordance with the less than 5% given by OSHA method 50. In conclusion, during the analysis of the EO in the HBr-coated charcoal, analysing immediately after desorption by DMF is more simple, precise, and efficient than other analysing methods, and the stability of the sample 24 hours after desorption was also established.ope

(The) differences of reflective levels between reflection-in-action and reflection-on-action and the changes of PCK in biology class

학위논문(석사) --서울대학교 대학원 :과학교육과(생물전공),2009.8.Maste

유전체 수준에서 벼 MADS-box 유전자들의 기능 연구

Docto

Locational Impact of Luminal Communication on Aortic Diameter Changes and Reintervention in Acute Type I Aortic Dissection

Objectives: The aim of this study is to evaluate the locational impact of a luminal communication on aortic diameter changes and reintervention after surgical repair of acute type I aortic dissection. Methods: Between 2009 and 2017, 304 patients underwent operation for acute type I aortic dissection. Among them, 93 patients were enrolled. The luminal communications were analysed in segment 1 (the proximal descending thoracic aorta), segment 2 (the distal descending thoracic aorta) and segment 3 (the abdominal aorta). The aortic diameter was measured at the pulmonary artery bifurcation, coeliac axis, maximal abdominal aorta and maximal thoraco-abdominal aorta using serial follow-up computed tomography scans. The linear mixed model was used, and the rate of freedom from reintervention was analysed. Results: In the adjusted analysis, the initial diameter of the maximal abdominal aorta and the first luminal communication in segment 1 was statistically significant. However, the slope value of the maximal abdominal aorta was smaller than that of the first luminal communication in segment 1 (0.024 vs 0.198). The 3-year freedom from reintervention rate was significantly higher in patients without a luminal communication than in those with an initial luminal communication in segment 1 (96% vs 47%, log rank, P = 0.003). Conclusions: A luminal communication at the proximal descending thoracic aorta (segment 1) is a significant factor for an increasing aortic diameter and reintervention after surgical repair of acute type I aortic dissection.restrictio

Surgery for acute Type I aortic dissection without resection of supra-aortic entry sites leads to unfavourable aortic remodelling

OBJECTIVES: This study aimed to evaluate the impact of remnant re-entries in arch branches on postoperative change in the aortic arch and descending aortic diameters and the rate of major adverse aortic events. METHODS: Between January 2010 and December 2016, 249 patients underwent surgery for acute Type I aortic dissection. Patients who underwent total arch replacement, had Marfan syndrome or had intramural haematoma were excluded. Seventy-two patients with predischarge and follow-up computed tomography scans were enrolled. Patients with and without re-entries in the arch branches after surgery were assigned to the supra-aortic entry (SAE, n = 21) and no supra-aortic entry (n = 51) groups, respectively. Diameters were measured at 7 levels: the innominate artery, left common carotid artery, left subclavian artery, 20 mm distal to the left subclavian artery, pulmonary artery bifurcation, coeliac axis and maximal diameter of the descending thoracic aorta. RESULTS: Growth rates at the levels of the pulmonary artery bifurcation and 20 mm distal to the left subclavian artery were significantly higher in the SAE group than in the no supra-aortic entry group. The rate of freedom from major adverse aortic events (annual growth >5 mm or maximal diameter of the descending thoracic aorta >50 mm) at 5 years was significantly higher in the no supra-aortic entry group than in the SAE group. CONCLUSIONS: Remnant SAE leads to unfavourable aortic remodelling after acute Type I aortic dissection repair.restrictio