A Study on the Improvement of Characteristic Properties of Protective Layers Prepared by Ion Beam Assisted Magnetron Sputtering Method

Iridium-based noble metal films, which show a relatively high oxidation resistance and high melting temperature, have been widely investigated as glass mold coatings due to its excellent reliability and performance in long-term high temperature usage. Recently, there has been an increasing interest in improving oxidation resistance and mechanical properties by the application for diffusion barrier layer and change of the alloy element content. In this work, we investigated the thermal stability and mechanical properties of the Ir-based films prepared by ion beam assisted magnetron sputtering method. The microstructures and surface morphology were analyzed by X-ray diffraction and Scanning Electron Microscopy. Auger depth profiling is used to examine chemical composition variation with the samples annealed at high temperatures. Ball on disc type wear test was used to examine wear amount with respect to alloy element contents. The micro hardness test has been also utilized to take the mechanical properties of the samples. In summary, two different sets of Ir based films(Ir-Re/Cr/Sub., Ir-Re/CrN/Cr/Sub.) were successfully deposited by ion beam assisted magnetron sputtering method. The Ir-Re/CrN/Cr sample showed more oxidation resistance than the Ir-Re/Cr sample, but higher than 500℃, both Ir-Re/Cr and Ir-Re/CrN/Cr samples were formed oxide phase, such as chromium oxide. Hardness values of the two different sets of Ir based films were decreased with increasing annealing temperature, while the values of the Ir-Re/CrN/Cr films were higher than these of Ir-Re/Cr films under high temperature conditions. Moreover, wear resistance are much improved with application for CrN barrier layer. The mechanical properties of the Ir-based films by the change of the alloy element content show that the hardness value is decreased with Re contents under high temperature conditions. This must have been due to increasing structural defects by the volatilization of Re2O7. But wear resistance improved with increasing Re content at room temperature.1. 서론 2. 이론적 배경 2.1 금형의 표면처리 기술 2.1.1 화학 기상 증착(CVD) 2.1.2 물리 기상 증착(PVD) 2.2 확산방지막의 개요 2.2.1 확산방지막의 종류 및 특성 2.2.2 CrN 박막 2.2.3 귀금속 재료의 특성 2.3 박막 증착의 원리 2.3.1 스퍼터링에 의한 박막 합성 2.3.2 스퍼터링 시 공정변수의 영향 2.3.3 비평형 마그네트론 스퍼터링의 원리 2.4 이온빔 2.4.1 엔드홀 이온건 2.4.2 이온빔 중성화 2.4.3 이온빔 전류 측정 2.5 이온빔 보조 증착 3. 실험 방법 3.1 실험 장치 3.2 시편의 제작 3.3 금형보호막 증착 3.3.1 확산방지막이 적용된 금형보호막 증착 공정 3.3.2 합금원소 조성변화에 따른 금형보호막 증착 3.4 시편의 분석 4. 실험 결과 및 고찰 4.1 확산방지막을 적용한 금형보호막의 특성 4.1.1 고온 열안정성 특성 평가 4.1.2 기계적 특성 평가 4.2 조성변화에 따른 금형보호막의 특성 4.2.1 스퍼터 파워 비율에 따른 증착막의 조성 4.2.2 조성변화에 따른 금형보호막의 표면 거칠기 4.2.3 조성변화에 따른 금형보호막의 열화학적 안정성 4.2.4 조성변화에 따른 금형보호막의 기계적 특성 5. 결

Two cases of sarcomatoid carcinoma of the liver associated with glomerulonephritis

Sarcomatoid carcinoma is a rare malignant neoplasm that may develop in various organs. Hepatocellular carcinoma with sarcomatous changes after anticancer therapy, such as hepatic arterial chemoembolization, has been reported, but primary sarcomatoid carcinoma of the liver is uncommon. Here, we report two cases of primary liver sarcomatoid carcinoma associated with glomerulonephritis in two men (68 and 55 years old, respectively) without any risk factors. Neither man was an alcoholic nor a hepatitis virus carrier, nor did either have a prior medical history of disease. Tumor markers were within normal ranges. In both men, imaging studies revealed a mass in the liver, with metastatic lesions on either the lung or sacrum, respectively. Histopathologic examination of the liver and kidney revealed sarcomatoid carcinoma of the liver and glomerulonephritis.ope

Risk of Adenomatous Polyps in the Proximal Colon according to Age and Gender

Background/Aims: Several lines of evidences suggest that the distribution of colorectal adenomatous polyps are different according to age and gender. Therefore, the efficacy of screening sigmoidoscopy for colorectal cancer not considering age and gender necessitates reappraisal. We aimed to evaluate the distributions of colorectal adenomatous polyps according to age and gender. Methods: Total of 1,886 patients (1,322 men, 564 women) who underwent colonoscopy at Severance hospital, Seoul, Korea between July 1995 and September 2002, were included. The proximal colon was defined as the colon proximal to the sigmoid-descending junction. The advanced polyp was defined as the adenomatous polyp with one or more of the following features: (1) 1 cm or larger in diameter, (2) villous histology, (3) high grade dysplasia or adenocarcimoma. Results: The risk of adenomatous polyps in the proximal colon was higher in men than women (OR, 1.63; 95% CI, 1.33∼1.99, p＜0.05), and increased with age (p＜0.05). The risk of advanced polyps in the proximal colon tended to be higher in men than women, and to increase with age, but did not reach statistical significance. Among 1,886 patients with colorectal adenomatous polyps, 587 patients (31.1%) had polyps only in the proximal colon. Among 814 patients with advanced colorectal adenomatous polyps, 217 patients (26.7%) had advanced polyps only in the proximal colon. The risks of adenomatous polyps or advanced polyps found only in the proximal colon were not different according to sex, but tended to increase with age. Conclusions: The risk of adenomatous polyps in the proximal colon was higher in men compared to women and increased with age. About one third of the patients with colorectal adenomatous polyps had polyps only in the proximal colon. Colonoscopy is a better strategy for endoscopic screening for colorectal cancer compared with sigmoidoscopy, especially, in elderly male.ope

A Case of Localized Concurrent Chemo-radiation Therapy Using with Tomotherapy for Hilar Hepatocellular Carcinoma with invasion of Bilateral Bile Duct

Hepatocellular carcinoma (HCC) usually takes an intrahepatic spread via portal vein branches, and the incidence of portal vein invasion is reported to be 34～40% in surgical resected series. On the other hand, the rate of intrabiliary growth of HCC is rare, ranging from 2.3～13% in surgical and autopsy cases. Here, we report a case of the patient treated with localized concurrent chemo-radiation therapy (CCRT) for hilar HCC with invasion of bilateral bile duct. The tomotherapy was performed with a total radiation dose of 4,240 cGy (20 times, 212 cGy/time) on tumor bed and hepatic arterial infusion of 5-fluorouracil (1,000 mg/day, day 1～5 and day 16～20) and cisplatin (60 mg/m2, day 3 and day 18) was done via implantable port system during the radiotherapy. After that, tumor size and tumor marker was decreased and treatment response was achieved as partial response. CCRT is expected as one of the appropriated treatment options for inoperable HCC with bile duct invasionope

Endoscopic Ultrasonographic Findings of Two Cases of Parasitic Eosinophilic Granuloma in the Stomach

Anisakiasis is a disease of the alimentary tract caused by nematode larva belonging to the subfamily Anisakinae. It is possible for Anisakis larva to be transmitted to man through eating raw sea fish that is preferred by Korean people. The clinical symptoms are characterized by severe cramping abdominal pain, nausea, vomiting, diarrhea, tarry stool, and epigastric fullness. The endoscopic examination has played a important role in the diagnosis of anisakiasis. However, gastric anisakiasis is undetected due to unspecific symptom and delayed endoscopy. Endoscopic ultrasonography is probably the choice of investigative tool for the evaluation of submucosal mass. However distinctive feature of parasitic infectation presenting an submucosal tumor has not been reported. Recently, we experienced two cases of gastric anisakiasis. We found gastric submucosal tumors by endoscopy, differentiated them by endoscopic ultrasonography and treated by endoscopic submucosal resection.ope

Clinical outcomes of systemic chemotherapy in hepatocellular carcinoma patients with multiple lung metastases

Background/Aims: Advanced hepatocellular carcinoma (HCC) with multiple lung metastases has a poor prognosis with no effective treatment having been established. This study evaluated the outcomes of systemic chemotherapy for advanced HCC with multiple lung metastases. Methods: Between January 2000 and December 2006, 68 patients were diagnosed with HCC presenting with multiple lung metastases. Sixteen patients in the terminal stage, such as Child-Pugh grade `C’ or an Eastern Cooperative Oncology Group performance status exceeding grade 2, were excluded from the analysis. The following treatment modalities were applied: 26 patients received primary tumor treatment (transarterial chemoembolization or intra-arterial chemotherapy) with systemic chemotherapy, 10 patients received primary treatment only, 8 patients received systemic chemotherapy only, and 8 patients received highly supportive care. The treatment responses and median survival times for the modalities were analyzed and compared. Results: The median age of the 52 analyzed patients (45 males) was 52.4 years. The most common etiology of HCC was chronic hepatitis B virus infection (n=44, 84.6%) followed by hepatitis C virus infection (n=2, 3.8%), with the etiology being unknown in 6 cases (11.5%). The treatment modality had no significant effect on the treatment response rate (P=0.432) or median survival time (133, 66, 74, and 96 days for primary tumor treatment with systemic chemotherapy, primary tumor treatment only, systemic chemotherapy only, and highly supportive care, respectively; P=0.067). Conclusion: We found that systemic chemotherapy was not effective in treating HCC presenting with multiple lung metastases. Improving the effectiveness of systemic treatment and selecting patients who would benefit from such treatment remains a major challengeope

Efficacy of Individual Prediction Model for the Early Diagnosis of Hepatocellular Carcinoma

Background: Screening tests for hepatocellular carcinoma (HCC) in the high risk population can detect tumors at an earlier stage and thus confer a higher chance of receiving treatment. However, the usefulness, frequency and cost-effectiveness of screening for HCC may differ in different areas, possibly reflecting differences in risk factors. Last decade, we have identified risk factors for HCC in 4339 Korean patients. The aim of this study was to investigate the efficacy and usefulness of individual prediction model for the early diagnosis of HCC. Methods: We studied a total of 833 patients who visited Yonsei University Medical Center for regular check-up including ultrasonography and alpha-fetoprotein from January 1999 to December 2000. The patients were classified into a low risk group ( 15%) by the probability of HCC development according to individual prediction model (IPM). The patients who developed HCC during the follow-up periods were analyzed using IPM. All the detailed data of clinical parameters were obtained by our self-exploited data base system prospectively and analyzed by SAS program. Results: 44 (5.3%) out of 833 patients developed HCC during mean follow-up periods of 36 months. According to IPM, 2 (0.62%) of 324 patients in the low risk group, 20 (4.84%) of 413 patients in the intermediate risk group, and 22 (22.9%) of 96 patients in the high risk group were diagnosed as HCC. In 29 of 44 HCC patients (65.9%), initial presentation of tumor size was less than 3 cm in diameter. Conclusion: We confirmed the reliability of established IPM for screening of HCC and this model may help screening program to be done effectively by focusing high risk groups for HCCope

Usefulness and Safety of Extracorporeal Liver Support Therapy Using MARS(R) for Patients with Liver Failure: A Preliminary Report

Background/Aims: The molecular adsorbent recirculating system (MARS(R)) is a form of artificial extracorporeal liver support and can be used for a bridge to spontaneous recovery of hepatic function or liver transplantation in patients with liver failure. This study evaluated the usefulness of MARS(R) in patients with liver failure. Methods: Between January 2004 and July 2007, 30 patients (21 males and 7 females; age 48.9±12.9 years) with acute or acute-on-chronic liver failure were managed using MARS(R). We assessed laboratory data, the grade of hepatic encephalopathy, Child-Turcotte-Pugh class, and Model for End-Stage Liver Disease (MELD) score. Results: The number of patients with acute liver failure and acute-on-chronic liver failure was 16 and 14, respectively. The mean cycle of MARS(R) in patients with liver failure was 2.2 sessions. After MARS(R) had been performed, serum total bilirubin, alanine aminotransferase (ALT), BUN, creatinine, ammonia level, daily urine output, and MELD score were improved (p＜0.05). In contrast, MARS(R) failed to improve Child-Turcotte-Pugh score and the grade of hepatic encephalopathy. Liver transplantation was performed in 8 patients. Among them, 5 (62.5%) patients survived and 3 (37.5%) patients died. Twenty two patients underwent MARS(R) without liver transplantation and 4 (18.2%) of them survived. Conclusions: In patients with liver failure, MARS(R) improved the laboratory data and hepatic and renal function associated clinical characteristics. However, MARS(R) without liver transplantation did not improve survival. MARS(R) may be useful as a bridge therapy to liver transplantation in patients with liver failureope

(A)Study on the design and performance characteristics of micropump using piezoelectric actuator

Thesis(master`s)--서울대학교 대학원 :기계항공공학부,2006.Maste