Impact Analysis on the Coastal Erosion and Accretion due to Relocation of Breakwaters

In recent years, the rate of mean sea level rise is rapidly increasing from the phenomena of global warming, together with the increasing trend of storm scale. The issue of sea level rise is multifaceted and produces a range of environmental problems. Especially, high tides and the tidal currents become higher, and wave base increases, so the energy received at the coastal boundary may increase. This brings that many coastal environments go into disequilibrium, such as damages to the structures, erosion, and deposition. Similarly it was known that the problems of nearshore processes and damage of berth and counter facilities during storm period had appeared at the small fishery port of Daebang, Samcheonpo Old and New ports, Korea. The purposed this study is try to analyze the impact due to rearrangement of counter facilities and berth layouts adopted for tranquility of those ports. Because these are being connected to Daebang channel, the rearrangement of the structures might affect to the current speed and direction and wave height, so does to the sea bottom undulation. Therefore, it is necessary to take model test for prediction of bottom change under the condition of new layouts of port facilities, and the combined wave and current impacts to the bottom were analyzed by numerical models. The formulated models were compared with the field observations and the possible bottom changes were discussed. Although the model study gave reasonable description of beach processes and approach channel sedimentation mechanism, it is necessary to compare with the long term based field history, including the records of waves, tides and bottom materials, etc. for better prediction.ABSTRACT ⅰ LIST OF TABLES ⅴ LIST OF FIGURES ⅵ NOMENCLATURE ⅷ 제1장 서론 1 1.1 연구의 배경 및 목적 1 1.2 해빈류에 대한 국내·외 연구 3 1.3 연구의 내용 4 제2장 수치모델의 기초이론 6 2.1 해수유동 6 2.1.1 해수유동의 지배방정식 6 2.1.2 와동점성계수 8 2.1.3 저면응력 성분 8 2.1.4 바람응력 성분 9 2.1.5 바람자료의 보정 10 2.2 풍파의 성장 및 전달 16 2.2.1 기초방정식 16 2.2.2 파랑 작용의 보존 방정식 17 2.3 표사이동 19 제3장 현장 환경 조사 21 3.1 조석 21 3.2 조류 25 3.3 파랑 28 3.4 바람 34 3.5 해저지질 조사 38 제4장 수치모형의 검증 및 적용 39 4.1 모형의 개요 39 4.1.1 해수유동 안정조건 42 4.1.2 파랑 지배방정식의 안정조건 42 4.2 수치모델의 검증 44 4.2.1 조위 검증 44 4.2.2 최강 조류속 검증 47 4.2.3 연속조류 관측성과 비교 49 4.3 수치모델의 결과 51 4.3.1 해수유동 결과 51 4.3.2 유속변화 정도 56 4.3.3 풍파성장 결과 62 4.3.4 표사이동 양상 65 4.3.5 지점별 저면 변화 70 4.3.6 단면별 저면 변화 73 제5장 결론 78 참 고 문 헌 8

A case of myocardial involvement in patient with MELAS syndrome

MELAS syndrome is characterized by mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, and cardiac involvement also frequently occurs. A 42-year-old female was admitted because of stroke like episodes and dyspnea. She had short status and hearing difficulty, and she complainded of general weakness. Brain MR revealed cortical sweeling and edema in temporal, parietal lobe and thalamus, which was not compatibe with stroke. Echocardiography revelaed hypertrophic left ventricular myocardium, resembling hypertrophic cardiomyopathy. Endomyocardial Biopsy confirmed myocardial involvement with MELAS syndrome.ope

Medullary Thyroid Carcinoma: 25-year Experience and the Results of the RET Proto-oncogene Screening Test

Purpose: Medullary thyroid carcinoma (MTC) is a rare thyroid tumor and its clinical course is quite variable. The aim of this study was to retrospectively analyze our clinical and laboratory data for 25 years to review the clinicopathologic characteristics, the operation methods, the tumor recurrence and the prognosis of medullary thyroid carcinoma. We also reevaluate the limits of the previous diagnostic and treatment modalities. The positivity for and the location of the RET mutation are also evaluated. Finally, we want to contribute to a systemic approach for the diagnosis, treatment, patient management and clinical study of medullary thyroid carcinoma. Methods: We conducted a retrospective review of the records of 77 patients with MTC that were seen at our hospital from 1982 to 2007. The medical records were reviewed for the demographic data, the laboratory data and the clinical course, the treatment, the long-term outcome and the RET proto-oncogene mutation. The mean follow-up period was 69.6 months (range: 6∼201). Results: There were 50 females and 27 males. The mean patient age was 44.2 years (range: 1∼80). There were 16 cases of the sporadic form (79.2%) and 16 cases of the hereditary form. At diagnosis, 73 patients (94.8%) had local disease and 4 patients (5.2%) had distant metastasis. The patients with the hereditary form were younger than the patients with the sporadic form (P=0.004), and they had more muticentric (P=0.002) and bilateral tumor (P＜0.001). The initial surgery consisted of total thyroidectomy in 74 patients (96.1%), and lateral neck dissection in 41 patients (53.2%) (therapeutic: 23, prophylactic: 18), except for 3 cases with less than total thyroidectomy. Forty-four patients (57.1%) achieved a long-term remission state, 13 patients (16.9%) had biochemical persistent disease, and 20 patients (26.0%) had metastasis. The 5- and 10-year survival rates were 86.5% and 74.1% respectively. On univariate analysis, tumor size (more than 2 cm), extracapsular invasion, involvement of the neck nodes and distant metastasis at the time of diagnosis were the significant prognostic factors of persistent or recurrence disease. Conclusion: Patients with MTC generally have a favorable outcome. The presence of distant metastasis at the time of diagnosis is predictive of persistent or recurrence disease by multivariate analysis. In order to achieve an early diagnosis and administer prompt treatment, we suggest that optimal RET oncogene screening and counseling should be performed for medullary patients and their relatives.ope

Gasless Endoscopic Thyroidectomy using the Trans-axillary Approach for Benign Thyroid Tumor

Purpose: The techniques for minimally invasive surgery in various surgical fields have recently become markedly developed. The endoscopic surgical methods for head and neck surgery have been introduced somewhat later due to some technical limitations. However, various endoscopic techniques have been remarkably developed during the last 10 years. We also introduced a novel method of gasless endoscopic thyroidectomy using the trans-axillary approach. The aim of this study is to evaluate the feasibility and surgical outcome of this method for treating patients with benign thyroid tumor. Methods: From Jan. 2002 to Dec. 2007, 171 patients with benign thyroid tumors underwent gasless endoscopic thyroidectomy via an axillary approach. We retrospectively analyzed the clinical and pathologic characteristics of the patients, the type of operation, the operative time, the post-operative hospital stay and the post-operative complications. Results: Among the 171 patients, the mean age of the patients was 33.3±10.0 years and the gender ratio was 1： 84.5 (males-2, females-169). The type of operation was classified according to the extent of surgery and there was no conversion to open thyroidectomy. The mean operation time and the mean length of the post-operative hospital stay were 129.7±51.6 minutes and 3.3±1.7 days, respectively. The mean tumor size was 2.70±1.18 cm and the most common pathologic diagnosis was adenomatous hyperplasia (106 cases, 62%). For the post-operative complications, transient hoarseness occurred in 6 patients, transient hypocalcemia occurred in 1 patient and trachea and esophageal injury occurred in 1 patient each. A tumor size larger than 5 cm and concurrent thyroiditis at time of the operation both increased the mean operation time (P= 0.009, P=0.023). Conclusion: According to our experience, gasless endoscopic thyroidectomy using a trans-axillary approach is a feasible and safe method for treating benign thyroid tumor. Moreover, the cosmetic benefits can be maximized by this method as compared with the other methods. Endoscopic thyroid surgery has become a new treatment modality for selected patients with benign thyroid tumorsope

Anaplastic Transformation of Metastatic Papillary Thyroid Carcinomas in the Cervical Lymph Nodes: Report of 3 Cases

Anaplastic thyroid carcinoma (ATC) is a rare disease that shows very aggressive behavior. Most ATCs arise from pre-existing thyroid carcinomas. However, anaplastic transformation occurring in metastatic cervical nodes is extremely rare. We report herein on 3 cases of anaplastic transformation of metastatic lateral cervical lymph nodes from primary papillary thyroid carcinoma (PTC), which happened long after the initial surgical treatment. All the patients died of disease within 4 months in spite of aggressive treatment for the lesions. Our experience supports that appropriate lymph node dissection is mandatory at the time of initial surgery even for differentiated thyroid carcinomas.ope

Robot-assisted Endoscopic Thyroid Surgery for Thyroid Cancer; Initial Experience of Consecutive 100 Patients

Background and Objectives: Various surgical procedures have been performed using surgical robot in recent years and most reports proved that application of robotic technology for surgery is technically feasible and safe. The aim of this study is to introduce our technique of robot-assisted endoscopic thyroid surgery and demonstrate its utility in the surgical management of thyroid cancer. Materials and Methods: From October 4th 2007 through March 14th 2008, 100 patients with papillary thyroid cancer underwent robot-assisted endoscopic surgeries using a gasless trans-axillary approach. This novel robotic surgical approach allowed adequate endoscopic access for thyroid surgeries. All the procedures were completed successfully using the da Vinci surgical system (Intuitive Surgical, Sunnyvale, California, USA). We used four robotic arms with this system; a 12 mm telescope and three 5 mm instruments. The 3-dimensional magnified visualization obtained by the dual-channel endoscope and tremor-free instruments controlled by robot system helped surgeon do sharp and precise endoscopic dissection. Results: We performed 84 less-than total and 16 total thyroidectomies with ipsilateral central compartment node dissection. Mean operation times was 136.5 min. (range 79∼267 min.) in which the actual time for thyroidectomy with lymphadenectomy (console time) was 60.0 min. (range 25∼157 min). The average number of lymph nodes resected was 5.3 (range 1 to 28). There was no serious complication. Most patients could go home within 3 days after surgery. Conclusion: Our technique of robotic-assisted endoscopic thyroid surgery using a gasless trans-axillary approach is feasible, safe and promising for the selected patients with thyroid cancer. We suggest application of robotic technology for endsocopic thyroid surgeries could overcome the limitations of conventional endoscopic surgeries in the surgical management of thyroid cancer.ope

Application of Robotic-assisted Mediastinal Lymph Node Dissection for Papillary Thyroid Cancer

There are three compartments of regional lymph node to which metastases from thyroid cancers can occur: central, lateral, and mediastinal compartment. The mediastinal metastases from thyroid cancers are extremely rare, comparing the relatively common forms of metastases to central or lateral compartments. The importance of complete surgical lymph node dissection of central or lateral compartment for thyroid cancer has been well described, but mediastinal lymph node dissection has been sporadically reported. For mediastinal compartment metastases, operation techniques consist of sternal split, thoracoscopic surgery, or VATS (Video-assisted thoracoscopic surgery). Robotic surgery system was introduced recently with the objective of enhancing the dexterity and view during procedure that uses a videoscope. Many institutions report the experience with minimally invasive resection of mediastinal mass using robotic surgery system. We report that one case of robot-assisted mediastinal lymph node dissection for metastatic papillary thyroid cancer.ope

A scoring system for prediction of lateral neck node metastasis from papillary thyroid cancer

Lateral neck node metastasis is an important prognostic factor in thyroid carcinoma. We developed a scoring system for use in prediction of lateral neck node metastasis from papillary thyroid cancer. In this study, 161 consecutive patients were included in the training data set. This scoring system, named the Yonsei Estimated Value (YEV) for lymph node metastasis in papillary thyroid cancer, was developed on the basis of results from multivariate logistic regression analysis of preoperative clinical and radiologic data. Sixty eight consecutive patients were included for testing of the validity of the scoring system. The equation for prediction of lateral neck node metastasis was follows:YEV (Yonsei Estimated Value) = 1/(1+X)X = Exp (5.333-[0.902 × sex]+[0.036 × age]-[1.020 × tumor size]-[0.177 × lymph node size]-[0.032 × lymph node density])When the YEV was 0.3 or more, the probability of lateral neck node metastasis was 79.0%, with sensitivity of 76.3%, specificity of 69.8%, positive predictive value of 56.7%, and negative predictive value of 85.1% in the training set. When fine needle aspiration biopsy for suspicious lateral neck nodes is not possible, or the results are inadequate, our scoring system for prediction of lateral neck node metastasis can be helpful in optimization of the surgical extent for each patient.ope

Clnicopathologic Features of Warthin-like Papillary Carcinoma of the Thyroid

Purpose: Warthin-like papillary carcinomawas named owing to its close histologic resemblance to a tumor encountered in salivary gland, and this tumor is a variant of papillary thyroid carcinoma. Among the variants of papillary thyroid carcinoma, the tall cell variant and diffuse sclerosing variant have more aggressive behavior than the classic papillary carcinoma. But Warthin-like papillary carcinoma arises in a background of thyroiditis and it behaves in an indolent fashion. Since then, a few case have reported in Korea. We report here on the clinicopathologic features of five cases of warthin-like papillary carcinoma. Methods: From Jan. 1996 to Feb. 2008, five patients who were diagnosed with Warthin-like papillary thyroid carcinoma at YUMC were retrospectively reviewed. Results: All 5 patients whose pathologic features were warthin-likepapillary thyroid carcinoma were women (age range: 34∼60 years). The tumor size ranged from 0.6 to 2.4 cm. 3 tumors were confined to the thyroid, but 2 tumors had invaded the strap muscles. 3 of the 5 tumors arose in a background of lymphocytic thyroditis. Central nodal metastases were identified in 2 cases. But no lateral nodal or distant metastasis had occurred. The mean duration of follow-up was 16.5 months (range: 5∼50 months). 1 patient died because of lung cancer, and there was no recurrence for the other 4 cases during the follow-up period. Conclusion: Although the long-term follow-up data on patients with Warthin-like papillary carcinoma is not available, the clinicopathologic data does not show that Warthin-like papillary carcinoma is any more aggressive than the usual papillary carcinoma.ope