Rho GTPase RhoJ is Associated with Gastric Cancer Progression and Metastasis

Rho GTPases play a pivotal role in tumor progression by regulating tumor cell migration and invasion. However, the role of Rho GTPases in gastric cancer (GC) remains unexplored. This study aimed to investigate the clinical implications of RhoJ, which is an uncharted member of Rho family. RhoJ expression in human GC cell lines and surgical specimens from GC patients were analyzed. Moreover, in vitro gain-of-function analysis was performed to evaluate the malignant phenotypes of RhoJ-overexpressing GC cells. The extent of RhoJ expression varied among GC cell lines and GC patients. YCC-9 cell line displayed the strongest expression, while YCC-10, -11, and -16 showed scant expressions. Of the 70 GC patients, 34 (48.6%) had RhoJ expression in their GC tissue, and patients with high RhoJ expression had more diffuse type GC (73.5% vs. 41.7%), were at more advanced stages (stage III, IV: 85.3% vs. 58.4%), and had more frequent metastasis (47.1% vs. 11.1%), denoting that RhoJ has a potential role in GC progression and metastasis. High RhoJ expression significantly correlated with poor overall survival and recurrence-free survival after surgical resection of gastric cancer. Finally, In vitro gain-of-function experiments showed 41.3% enhanced motility and 60.4% enhanced invasiveness in RhoJ-overexpressing GC cells compared to control, with negligible difference in cell proliferation. Collectively, high RhoJ expression is an independent negative prognostic factor for the survival outcome of GC and correlated with the increased cell motility and invasiveness.ope

PTEN loss and level of HER2 amplification is associated with trastuzumab resistance and prognosis in HER2-positive gastric cancer

Background: Trastuzumab is an active agent against human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC). This study aimed to characterize resistance to trastuzumab-based front-line chemotherapy in HER2+ GC patients and to establish factors predictive of this resistance. Results: Among 129 HER2+ GC patients, 25% displayed rapid disease progression within 4 months from initiation of therapy. These patients showed a higher rate of signet ring cell histology, bone metastasis, poor performance status, frequent loss of PTEN expression, and low HER2 amplification index compared with patients who were progression-free for at least 4 months. In contrast, there was no significant difference in the frequency of the PIK3R1 variant. Multivariate analyses confirmed two independent molecular predictors for trastuzumab resistance: loss of PTEN expression and low HER2 amplification index (<5). Patients with one or both molecular predictors at diagnosis exhibited worse progression-free and overall survival compared to those without risk factors (p < 0.001 and p = 0.001, respectively). Conclusion: In HER2+ GC patients, loss of PTEN expression and low HER2 AI correlated with resistance to trastuzumab-based therapy and dismal prognosis. Since patients harboring these molecular predictors are unlikely to respond to trastuzumab-based therapy, other novel therapeutic targets needed to be considered. Methods: HER2+ GC patients who were treated with trastuzumab in combination with either 5-fluorouracil/cisplatin or capecitabine/cisplatin were enrolled. Clinicopathologic features and molecular alterations of HER2, phosphoinositide 3-kinase regulatory subunit 1 (PIK3R1), and phosphatase and tensin homolog (PTEN) were correlated with treatment outcome. Factors predictive of resistance were also explored.ope

Genetic alterations and their clinical implications in gastric cancer peritoneal carcinomatosis revealed by whole-exome sequencing of malignant ascites

Peritoneal carcinomatosis accompanied by malignant ascites is a major cause of death of advanced gastric cancer (GC). To comprehensively characterize the underlying genomic events involved in GC peritoneal carcinomatosis, we analyzed whole-exome sequences of normal gastric tissues, primary tumors, and malignant ascites from eight GC patients. We identified a unique mutational signature biased toward C-to-A substitutions in malignant ascites. In contrast, the patients who received treatment of adjuvant chemotherapy showed a high rate of C-to-T substitutions along with hypermutation in malignant ascites. Comparative analysis revealed several candidate mutations for GC peritoneal carcinomatosis: recurrent mutations in COL4A6, INTS2, and PTPN13; mutations in druggable genes including TEP1, PRKCD, BRAF, ERBB4, PIK3CA, HDAC9, FYN, FASN, BIRC2, FLT3, ROCK1, CD22, and PIK3C2B; and mutations in metastasis-associated genes including TNFSF12, L1CAM, DIAPH3, ROCK1, TGFBR1, MYO9B, NR4A1, and RHOA. Notably, gene ontology analysis revealed the significant enrichment of mutations in the Rho-ROCK signaling pathway-associated biological processes in malignant ascites. At least four of the eight patients acquired somatic mutations in the Rho-ROCK pathway components, suggesting the possible relevance of this pathway to GC peritoneal carcinomatosis. These results provide a genome-wide molecular understanding of GC peritoneal carcinomatosis and its clinical implications, thereby facilitating the development of effective therapeutics.ope

Changes in telomerase activity due to alternative splicing of human telomerase reverse transcriptase in colorectal cancer

Human telomerase reverse transcriptase (hTERT) expression level may not always correlate with telomerase activity. The present study analyzed hTERT splicing patterns with respect to hTERT and telomerase activity in colorectal cancer. Telomerase activity was determined by telomeric repeat amplification protocol assay, and spliced variants of hTERT were identified by reverse transcription-polymerase chain reaction in 40 colorectal cancer tissue samples. In the lower range of telomerase activity (0-100 units), the percentage of the β variant decreased with the increment in telomerase activity, whereas in the higher range of telomerase activity (>100 units), total hTERT expression level revealed a trend toward increment. There was a positive correlation between the full-length variant level and β variant level. Conversely, there was a negative correlation between the percentage of the full-length variant and β variant. Tumor-node-metastasis stage was the strongest prognostic factor in multivariate analysis and the percentage of the full-length variant was an independent prognostic factor for survival. Telomerase activity was primarily altered with changes in alternative splicing of the full-length and β variants of hTERT in colorectal cancer.ope

Comprehensive immune profiling and immune-monitoring using body fluid of patients with metastatic gastric cancer

BACKGROUND: The aim of this study is to profile the cytokines and immune cells of body fluid from metastatic gastric cancer (mGC), and evaluate the potential role as a prognostic factor and the feasibility as a predictive biomarker or monitoring source for immune checkpoint inhibitor. METHODS: Body fluid including ascites and pleural fluid were obtained from 55 mGC patients and 24 matched blood. VEGF-A, IL-10, and TGF-β1 were measured and immune cells were profiled by fluorescence assisted cell sorting (FACS). RESULTS: VEGF-A and IL-10 were significantly higher in body fluid than in plasma of mGC. Proportion of T lymphocytes with CD69 or PD-1, memory T cell marked with CD45RO, and number of Foxp3+ T regulatory cells (Tregs) were significantly higher in body fluid than those in blood of mGC. Proportion of CD8 T lymphocyte with memory marker (CD45RO) and activation marker (HLA-DR), CD3 T lymphocyte with PD-1, and number of FoxP3+ Tregs were identified as independent prognostic factors. When patients were classified by molecular subgroups of primary tumor, VEGF-A was significantly higher in genomically stable (GS)-like group than that in chromosomal instability (CIN)-like group while PD-L1 positive tumor cells (%) showed opposite results. Monitoring immune dynamics using body fluid was also feasible. Early activated T cell marked with CD25 was significantly increased in chemotherapy treated group. CONCLUSIONS: By analyzing cytokines and proportion of immune cells in body fluid, prognosis of patients with mGC can be predicted. Immune monitoring using body fluid may provide more effective treatment for patients with mGC.ope

Structural topology design optimization using parallel computers

학위논문(박사)--서울대학교 대학원 :기계항공공학부,2001.Docto

조직정합성 모델을 활용하여

학위논문 (석사)-- 서울대학교 대학원 : 행정대학원 행정학과, 2019. 2. 김병섭.본 연구는 D. A. Nadler & M. L. Tushman(1989)이 제시한 조직정합성 모형을 토대로 조직효과성에 영향을 미치는 요인을 분석하고자 하였다. 이전의 관련 선행연구들은 조직문화 또는 리더십 유형, 소통수준 등 개별 영역(요인)의 수준이 조직효과성에 어떤 영향을 미치는지에 대한 단편적 진단과 처방에 그치는 한계를 안고 있다. 한계를 보완하고자 하였다. 이를 위해 조직효과성에 영향을 미치는 조직구성요소와 영역을 망라하여 진단 및 분석을 진행하였다. 업무, 사람, 공식조직, 비공식조직 등 4개의 영역에 대한 조직 구성원의 인식도(만족도)가 조직효과성과 어떤 연관관계를 갖는지 확인하고, 조직변화와 혁신을 위해 어떤 부분에서 개선이 필요한지에 대한 복합적이고 입체적 시각과 처방을 제시하고자 하였다. 조직정합성 모형은 기존의 조직진단이 조직의 다차원적 동태성을 유기적으로 진단하지 못하는 한계를 극복할 수 있다는 장점을 갖는다. 이 모형을 기초로 단일 공공기관(공기업) 임직원을 대상으로 설문조사를 진행하였고, 그 결과를 바탕으로 한 실증분석을 통해 조직효과성에 영향을 미치는 요인들을 살펴보았다. 또한 실증분석이 각 요인의 현재 상태가 왜 이러한 상황인지에 대한 조직 구성원의 실제 인식과 직접적인 의견을 파악하는 데는 한계가 있다는 점을 고려하여 심층인터뷰 등을 활용한 질적 방법론을 병행하여 연구를 진행하였다. 이를 통해 개별 영역의 현재 수준 자체뿐만 아니라 관련 영역 간의 정합성과 향후의 변화 방향, 개선방안까지 제시할 수 있는 자료를 확보하고자 하였다. 본 연구에서 양적 연구는 연구대상 조직 전체 임직원을 대상으로 한 설문조사 결과를 실증분석 하였다. 독립변수는 조직정합성 모형을 준용하여 업무, 사람, 공식조직, 비공식조직 등 4개 요인으로 정의하고, 종속변수는 조직효과성을 측정하기 위한 지표로서 조직만족도, 직무만족도, 조직몰입도를 설정하였다. 실증분석 결과, 업무, 사람, 공식조직, 비공식조직에 대한 만족도는 비공식조직>사람>업무>공식조직의 순서로 높은 만족도를 나타냈다. 변수 간 상관관계 분석결과 업무, 사람, 공식조직, 비공식조직과 조직효과성 간에는 모두 정(+)의 상관관계를 가지고 있으며, 4가지의 조직구성요소 간에도 정(+)의 상관관계를 나타냈다. 응답집단별 만족도 차이를 분석한 결과 성별 구분에 따른 차이는 업무변수 중 근무환경 만족도, 사람변수 중 성과관리 역량, 공식조직 변수 중 조직구조, 인사제도, 직급효과성 항목 및 조직효과성 변수 중 직무만족도에 대한 인식의 차이가 유의미한 것으로 확인되었다. 또한 연령에 따른 인식의 차이 분석 또한 유의미한 결과를 얻을 수 있었는데, 업무/사람/공식조직/비공식조직 및 조직효과성에 대한 인식에 있어 20대와 30대가 40대와 50대 이상의 연령층에 비해 높은 만족도를 나타내고 있었다. 가설검정을 위한 회귀분석결과 본 연구대상에서는 업무와 사람, 공식조직이 조직효과성에 정(+)의 영향을 미치는 것으로 나타났으며, 비공식조직의 경우 조직효과성에 유의미한 영향을 미치지 못하는 것으로 확인되었다. 4개요인들 간의 정합성도 조직효과성에 영향을 미칠 수 있다는 점을 감안하여 조직의 변화와 혁신을 추진해야 한다는 정합성 모델의 기본원리에 따라 요인 간 정합성을 진단하고자 심층 인터뷰를 진행했다. 업무, 사람(조직 구성원의 역량), 공식조직, 비공식조직의 조직효과성에 미치는 영향력은 통계적 분석을 통해서 그 정도와 상관관계를 확인할 수 있다고 하더라도 맥락적 이해와 본질적 이유, 향후의 변화의 방향과 방안에 대한 부분은 요인 간 정합성 분석을 위한 심층인터뷰를 통해서 보다 많은 해석과 유의미한 결론을 도출할 수 있었다. 구체적으로는 많은 공공기관의 혁신과정에서 리더십 스타일, 바람직한 조직문화 구축 등의 인식과 의식의 혁신을 강조하는 흐름이 강조되는 최근의 혁신 트렌드와 달리 전통적인 제도적 개선이 반드시 뒷받침 되어야 한다는 결론을 얻을 수 있었다. 본 연구의 결과를 종합할 때, 공공기관 경영평가 등에서 분야별 진단과 평가 결과의 단순 취합이 아니라 해당 공공기관의 혁신적 변화를 위해 가용한 자원과 노력을 어떤 영역에 집중 또는 배분해야 하는지에 대한 시사점을 확인할 수 있었다. 더불어 향후의 공기업, 공공기관, 정부조직의 조직운영방식에서의 개선과 혁신 관점과 방법이 어떻게 재정립 되어야 하는지에 대한 시사점을 제시할 수 있다.This study was conducted to analyze the factors that affect organizational effectiveness based on the congruence model suggested by N. A. Nadler & M. L. Tushman (1989). The limitation of preceding studies is that they were single-sided diagnosis and prescriptions concerning the influence of individual factors, such as organizational culture, leadership type, and level of communication, on organizational effectiveness. I tried to resolve that limitation. In order to do so, I listed the factors and areas of organizational structure to diagnose and analyze their influence on organizational effectiveness. I checked how the perception (satisfaction) of organization members is correlated to organizational effectiveness in four areas-work, people, official organizations, and unofficial organizations. Then I suggested a comprehensive, multifaceted visuals and prescriptions as to which parts should be improved for the change and innovation of organization. The congruence model is capable of overcoming the limitations of the preceding diagnosis of organizations which failed to examine the multidimensional dynamics of organizations. The officers and employees of public organizations were surveyed based on this model, and a substantial analysis was conducted based on the findings to identify the factors that affected organizational effectiveness. I also considered that substantial analysis cannot identify the actual perception and opinion of organization members in regards to the condition of each factor and adopted a quantitative methodology which involved an in-depth interview. By doing so, I secured the resources not only on the current condition of each individual area, but also on their congruence, future changes, and improvement possibilities in relation to other areas. In this study, the quantitative study involved the substantial analysis of the results of a survey on the officers and employees of the entire organization. The independent variables of the congruence model were work, people, official organization, and unofficial organization and the dependent variables were organizational satisfaction, occupational satisfaction, and organizational commitment used to measure organizational effectiveness. As a result of the substantial analysis, satisfaction with work, people, official organizations, and unofficial organizations were high for unofficial organizations>people>work> official organizations. As a result of analyzing the correlation between variables, there were positive correlations between work, people, official organizations, or unofficial organizations and organizational effectiveness and positive correlations among the four factors. As a result of analyzing the differences in the satisfaction of each response group, gender created a significant difference in the perception of satisfaction with work environment among the work-related variables, performance management capacity among the people-related variables, organizational structure, human resources systems, and position effectiveness among the official organization variables, and satisfaction with occupation among the organizational effectiveness variables. The analysis of differences in perception by age also showed significant resultsthose in the 20s and 30s showed a higher level of satisfaction in terms of work/people/official organizations/unofficial organizations and organizational effectiveness compared to the 40s and 50s and older. As a result of regression analysis for the test of hypotheses, work, people, and official organizations had a positive influence on organizational effectiveness, where as unofficial organizational did not. Considering that the congruence of the four factors can also affect organizational effectiveness, an in-depth interview was conducted to diagnose the congruence of factors based on the basic principle of congruence model that an organization must pursue change and innovation. Although statistical analysis could identify the degree and correlation of influence of organizational effectiveness on work, people (capability of members), official organizations, and unofficial organizations, the in-depth interview for congruence analysis was able to draw more interpretations and meaningful conclusions in terms of contextual comprehension, essential reasons, and future changes. In detail, it was concluded that many public organizations' innovation must accompany the renovation of conventional systems when the latest trends of innovation emphasize the innovation of perception and awareness in regards to the leadership styles and the desirable organization culture. Considering the findings of this study, it implies that the management evaluation of public organizations should not just gather the results for diagnosis and evaluation, but ponder how to concentrate or distribute the available resources and efforts for the innovative change of public organizations. Not only that, it suggests how the focus and methodology of improvement and innovation should be reestablished in the future for the operation of public corporations, public organizations, and government organizations.제 1 장 서론 1 제 1 절 연구의 목적 및 필요성 1 제 2 절 연구의 대상과 방법 5 1. 연구의 대상 5 2. 연구의 방법 6 제 2 장 이론적 논의와 선행연구 검토 9 제 1 절 조직효과성의 개념 및 선행연구 9 1. 조직효과성의 개념과 의의 9 2. 조직효과성의 측정 10 3. 조직효과성에 영향을 주는 요인에 대한 선행연구 11 제 2 절 정합성 모형(Congruence Model) 관련 선행연구 15 1. 정합성 모형(Congruence Model)의 개념 15 2. 정합성 모형(Congruence Model)에서의 조직 구성요소 16 3. 조직정합성 모형(Congruence Model)에서의 구성요소들 간의 정합성 21 4. 정합성 모형(Congruence Model)을 활용한 기존 연구 27 제 3 장 연구 설계 및 분석 방법 30 제 1 절 분석의 틀 및 가설 설정 30 1. 분석의 틀 30 2. 가설의 설정 32 3. 변수의 조작적 정의 및 측정 32 4. 심층 인터뷰 36 제 2 절 자료의 수집 및 분석방법 39 1. 연구대상 39 2. 자료의 수집 및 설문의 구성 39 3. 분석 방법 41 제 4 장 실증분석 43 제 1 절 측정도구의 타당성 및 신뢰도 분석 43 1. 타당성 및 신뢰도 검증 43 2. 동일방법 편의(Common Method Bias, CMB) 검증 45 3. 변수간의 상관관계 분석 45 제 2 절 기초통계 분석 47 1. 조사 대상의 인구통계학적 특성 47 2. 변수별 기술통계량 49 3. 응답집단별 인식의 차이 분석 52 제 3 절 회귀분석 62 제 5 장 심층인터뷰를 통한 조직정합성 검토 64 제 1 절 심층인터뷰 개요 64 1. 심층인터뷰 진행방법 및 일정 64 2. 심층인터뷰 진행대상 프로필 65 3. 정합성 진단을 위한 질의사항 66 제 2 절 심층인터뷰 분석 결과 68 1. 업무–사람(조직구성원) 간 정합성 분석 68 2. 업무-공식조직 간 정합성 77 3. 업무-비공식조직 간 정합성 88 4. 사람–공식조직 간 정합성 95 5. 사람–비공식조직 간 정합성 102 6. 공식조직-비공식조직 간 정합성 113 제 3 절 심층 인터뷰 결과의 시사점 118 제 6 장 결론 123 제 1 절 연구결과 요약 및 정책적 시사점 123 1. 연구결과의 요약 123 2. 연구의 정책적 시사점 128 제 2 절 연구의 한계와 과제 132 참고문헌 134 Abstract 138Maste

Rheological, Mechanical and Morphological Properties of Polycarbonate Blends with different properties and structure of impact modifier

학위논문 (석사)-- 서울대학교 대학원 : 공학전문대학원 응용공학과, 2019. 2. 안경현.Recently, a variety of TV products have become increasingly larger, thinner, and more complicated depending on the needs of the consumers who require the combination of function and design, and it is becoming important to improve durability according to long-term use. To meet these customers needs, PC blends based on polycarbonate (PC) with excellent shock, heat resistance, and dimensional stability are widely used for TV housing products. PC blends are produced by blending with various materials, such as inorganic filler (Glass fiber, Talc) for improving dimensional stability and prevention of deformation, flame retardant (BDP) for ensuring flame retardancy. However blending with various inorganic fillers (Glass fiber, talc) and flame retardant (BDP) causes a problem of lowering the impact resistance of the housing product, so the role of impact modifier in PC blending materials is becoming more important. Therefore, this research has been explored about the correlation analysis of impact properties, dispersibility, and rheological properties of PC/MBS materials with changes of impact modifier (MBS) Graft Density, when the MBS has applied among the blend materials of Polycarbonate. First, impact modifier (MBS) with different graft density was prepared by emulsion polymerization. PC/MBS blends were produced by using twin screw extruder. And then, Izod impact properties of PC blends with impact modifier (MBS) were analyzed according to ASTM. Transmission electron microscopy (TEM) was used to confirm the dispersion shape of impact modifier (MBS) in PC matrix and the rheological properties were measured using a Rheometer. As a result of this study, it was confirmed that the impact modifier MBS in PC/MBS blend material gets better dispersibility of impact modifier in PC system when the Graft Density has low level, while the impact property has decreased. Also in the rheological analysis, it was confirmed that the storage modulus (G ') tends to decrease at a long relaxation time (low frequency) as the graft density of MBS decreases. These results are ascribed to the influence of surface affinity and interfacial adhesion between PC and MBS depending on the graft density of MBS. In this study, we confirmed the correlation of impact properties, rheology, and morphology of impact modifier(MBS) in PC blend material. Further, we established research methodology and secured basic research data for concreting the direction of company's impact modifier development in the future. K최근 다양한 TV 제품은 기능과 디자인이 결합된 특성을 요구하는 소비자의 니즈에 따라 더욱 더 대형화되고, 얇아지고, 복잡한 형태로 변화하고 있으며, 또한 장기적인 사용에 따른 내구성 향상이 중요해지고 있다. 이러한 고객의 요구를 만족시키기 위해 TV Housing 제품에는 내충격성, 내열성, 치수 안정성이 뛰어난 폴리카보네이트(PC)를 기본 베이스로 하는 PC 블렌드용 소재가 널리 적용되고 있다. 이러한 소재는 치수 안정성 향상 및 변형 방지를 위한 무기 필러(유리섬유, 탈크) 적용 및 난연성 확보를 위한 난연제(BDP)와 블렌드를 하는 등 다양한 재료와의 블렌딩을 통한 복합 재료를 제작하여 적용하고 있다. 하지만, 이러한 다양한 무기 필러(Glass fiber, Talc) 및 난연제(BDP)와의 블렌딩은 하우징 제품의 내충격성을 하락 시키는 문제를 발생시키므로, PC 블렌딩 소재에서 충격 보강제(impact modifier) 역할의 중요성이 대두되고 있다. 따라서 본 연구에서는 Polycarbonate 블랜드용 소재에서 코어/쉘 구조의 충격보강제(impact modifier)인 MBS(methyl methacrylate butadiene styrene)를 적용했을 때 MBS Graft Density의 변화에 따른 PC/MBS 소재의 충격 물성, 분산성, 유변학 특성과의 상관관계 분석에 관한 연구를 진행하였다. 우선 유화중합을 통하여 Graft density가 차이가 나는 충격보강제(MBS)를 제작하였고, 치합형 동방향 회전 이축 압출기를 사용하여 PC/MBS 블랜드물을 제조하였다. ASTM에 의거하여 Graft Density 별 충격 보강제가 적용된 PC/MBS의 Izod 충격 물성을 분석하였고, 투과 전자 현미경(TEM)을 활용하여 PC 매트릭스에서의 충격보강제(MBS)의 분산 형태를 확인하였다. 그리고 레오미터 (Rheometer)를 이용하여 유변학적 특성을 측정하였다. 본 연구 결과, PC/MBS 블렌드 소재에서 충격보강제 MBS의 Graft Density가 낮을수록 PC계 내에서의 충격 보강제의 분산성은 좋아지며, 반대로 충격 물성은 하락하는 것을 확인하였다. 유변학 분석에서도 MBS의 Graft Density가 작아질수록 장시간 완화시간 영역(낮은 주파수)에서 저장 모듈러스(G')가 하락하는 경향을 확인하였다. 이러한 결과는 MBS의 Graft Density에 따라 PC와 MBS간 계면간의 표면 친밀도(Surface Affinity) 및 계면 접착력 차이에 따른 영향성으로 인해 나타나는 결과로 보인다. 본 연구를 통하여 PC 블렌드 소재에서 충격 보강제 MBS의 Graft density에 변경에 따른 충격 물성, 유변학, 모폴로지의 상관관계를 검증하여 연구 방법론 정립 및 기초 연구 자료를 확보함으로써, 향후 회사의 충격 보강제 개발 방향을 설정하는 기반을 마련하였다.목 차 제 1 장 서 론 1 1.1 연구 배경 1 1.2 연구 내용 4 1.2.1 연구 목적 4 1.2.2 연구의 필요성 4 1.2.2 연구의 결과물 5 제 2 장 이론적 배경 및 선행 연구 6 2.1 폴리카보네이트(PC) 6 2.2 포스페이트계(Phosphate) 난연제 8 2.3 코어/쉘 충격보강제(Core/shell Impact Modifier) 10 2.3.1 유화 중합(Emulsion polymerization) 12 2.3.2 Graft density 14 2.4 고분자 블렌드 15 제 3 장 실험 17 3.1 충격보강제(MBS) 제조 17 3.2 실험 재료 19 3.3 PC/MBS 블렌드물 제조 20 3.4 사출 시편의 제조 23 3. 5 Izod 충격 시험 23 3. 6 투과 전자 현미경(TEM) 분석 23 3. 7 유변학 분석 23 제 4 장 결과 및 고찰 25 4.1 형태학(Morphology) 분석 25 4.2 충격 물성 분석 30 4.3 유변학 분석 33 4.4 graft ABS 적용 실험 36 제 5 장 결론 및 시사점 40 참 고 문 헌 43 Abstract 45Maste

(An) electromyographic study of the muscle activity in Angle's Class II div. 1 malocclusion and normal occlusion

치의학과/석사[한글]두개안면부의 골격형태와 교합상태는 저작근의 기능과 밀접한 관계가 있으며, 이런 상호관계는 교정치료전의 진단과 치료후의 최종적 교합안정성에 중요한 요소가 된다. 저자는 두개안면부의 골격형태와 교합상태에 따른 저작근 기능의 상호관계를 비교하기 위하여 12∼14세인 Angle씨 Ⅱ급1류 부정교합자인 남자 15명과, 정상교합자인 남자 15명을 대상으로 두부방사선 계측사진을 촬영하여 12항목을 계측하였고, 근육활성도를 측정하기 위해 전측두근, 후측두근, 교근, 구륜근의 하악 안정위, 저작시, 연하운동시의 근전도 검사를 시행하여 통계처리한 후 다음과 같은 결론을 얻었다. 1. 하악 안정위에서의 근육활성도는 Angle씨 Ⅱ급1류 부정교합군과 대조군에서 모두 후측두근이 가장 크게 나타났으며, 후측두근의 활성도는 Angle씨 Ⅱ급1류 부정교합군에서 대조군보다 더 크게 나타났다. 2. 저작시의 근육활성도는 Angle씨 Ⅱ급1류 부정교합군이 대조군보다 모든 근육에서 작게 나타났으며, 두 군 모두에서 전측두근이 후측두근보다 큰 활성도를 보였다. 3. 구륜근은 두부골격형태와 교합상태에 관계없이 개구시가 폐구시보다 더 큰 근육활성도를 보였다. 4. 연하운동시 Angle씨 Ⅱ급1류 부정교합군에서 대조군보다 전측두근, 교근 및 구륜근의 근육활성도가 작게 나타났다. [영문]This study was performed to investigate the relationships between the EMG activity of the masticatory muscles in Angle's Class Ⅱ div. 1 malocclusion and normal occlusion. This study was ranged from age 12 to 14 year-old for 30 male subjects: 15 subjects were Angle's Class. Ⅱ div. 1 malocclusion, and 15 subjects were normal occlusion with acceptable profile. Their cephalometric measurement were analyzed, and the EMG recordings from the anterior temporal, posterior temporal, masseter, and orbicularis oris muscles were analyzed during rest position, mastication of peanuts, and swallowing. All data was recorded and statistically processed with the VAX-11/780 computer system. The results were as follows: 1. The activity of muscles at rest was highest in the posterior temporal muscle with normal occlusion, as well as in those with Class Ⅱ dirt, 1 malocclusion, and the posterior temporal muscle activity of Class Ⅱ div. 1 malocclusion was higher than that of normal occlusion. 2. During mastication, all muscle activities of Class Ⅱ div. 1 malocclusion were recorded lower than those of normal occlusion, and the activity of the anterior temporal muscle was higher than that of the posterior temporal muscle in both types of occlusion. 3. As for the activity in orbicularis oris muscle, it was greater in opening phase than in closing phase during chewing cycle with both types of occlusion. 4. During swallowing, the activities of the anterior temporal, masseter, and orbicularis oris muscles of Class Ⅱ div. 1 malocclusion were recorded lower than those of normal occlusion.restrictio