콘빔 CT 영상을 이용한 사람 악골의 3차원 골 미세구조 분석

학위논문 (박사)-- 서울대학교 대학원 : 치의과학과, 2014. 2. 허경회.1. Objective The purpose of this study was to define the potential usability of cone beam computed tomography (CBCT) in the assessment of trabecular bone microarchitecture. 2. Materials and Methods Sixty eight cylindrical bone specimens were prepared from 4 pairs of 4 human jaw bone. The specimens were scanned using both micro-CT and CBCT. The voxel sizes of micro-CT and CBCT were 19.37 μm and 100 μm, respectively. With micro-CT, additional reconstruction images with 96.87 μm voxel size were acquired to simulate the CBCT images of 100 μm voxel size. Three-dimensional (3D) morphometric analysis was performed in each set of images and the morphometric parameters were calculated. The correlation of parameters between the micro-CT and the CBCT was evaluated using the linear correlation test. 3. Results The bone volume (BV), percent bone volume (BV/TV), trabecular separation (Tb.Sp), and degree of anisotropy (DA) of CBCT images showed strong correlations (Pearson correlation coefficient, r > 0.5) with those of micro-CT with 19.37 μm voxel size (P <0.05). Although some parameters such as bone surface (BS), bone surface density (BS/TV), trabecular bone pattern factor (Tb.Pf), structural model index (SMI), and trabecular number (Tb.N) showed relatively weak correlation (Pearson correlation coefficient, r < 0.5), still, they showed statistically significant linear correlation (P < 0.05). Among the 3D morphometric parameters, DA showed the strongest correlation between CBCT and micro-CT with 19.37 μm voxel. The parameters showing linear correlation between CBCT and micro-CT with 19.37 μm voxel were consistent with those between CBCT and micro-CT with 96.87 μm. 4. Conclusion Most morphometric parameters from CBCT were correlated with those of micro-CT. Parameters showing strong correlation such as BV, BV/TV, Tb.Sp, and DA would be used to evaluate the bone quality using CBCT.I. Introduction II. Materials and Methods III. Results IV. Discussions V. Conclusion VI. References Abstract (Korean)Docto

A Study on the Variability of Perception and the Possibility of its Expansion - based on Bergsons theory of perception -

학위논문 (석사)-- 서울대학교 대학원 : 미학과, 2016. 2. Peter. W. Milne.지각은 대상의 식별과 관계된 인식의 기초이자, 다가 올 미래를 준비하는 행동의 근간이다. 한마디로 사유하고 행위하며 살아가는 생명체에게 있어, 지각이란 생의 전 경험의 토대와 같다. 본고는 이러한 지각을 프랑스 현대 철학자 베르그손의 지각론을 토대로 살펴보고자 한다. 베르그손은 현재의 지각이 대상의 물질성을 담보하는 것인 동시에, 과거의 기억을 참조하여 질적인 재조직화를 이룬 것이라는 독창적인 주장을 전개하였다. 우리는 하나의 대상을 늘 동일하게 지각한다고 생각하지만, 지각은 본질적으로 가변적이다. 주체의 정신이 대상에 어떤 성향의 주의를 얼마나 기울이는지에 따라 지각의 질감이 달라지기 때문이다. 생명체의 삶을 주재하는 정신의 성향은 끊임없이 변화하는 세계 속에서 안정적으로 살아가고자 하는 삶에의 주의이다. 따라서 일상적인 지각은 대상의 고유한 뉘앙스들을 일정 부분 탈각한 채, 그것이 무엇이며 어디에 쓰이는지를 파악하는 차원으로 축소되어 있다. 그러나 생존만을 목적 삼지 않는 고등 생명체인 인간의 정신에는 생존을 위해 제거되어 온 질적인 특이성들에 주목하는 성향 역시 존재한다. 본고는 이를 반성적 주의로서 명명하며, 이 주의가 작동할 때 지각은 평소 무용하다고 억제되어 온 차이의 질감들을 보다 많이 담아내면서 확장된다는 사실을 주장하고자 한다. 베르그손에 따르면, 일상적인 지각의 한계를 넘어 지각의 확장을 능동적으로 성취해 온 인물들이 바로 위대한 예술가들과 철학자들이다. 이들은 실익을 따지는 삶의 정향으로부터 벗어나, 대상의 일반화되지 않는 개별성과 독자성을 향해 주의를 전향하는 자들이다. 이처럼 베르그손의 사유에서 예술과 철학의 목적은 삶의 유지를 위해 부득이하게 축소되어 있는 지각을 확장시키고 완성하는 차원으로 거듭난다. 특히 이는 그의 독자적인 개념인 직관, 즉 모든 매개를 거부한 채 대상 속으로 들어가 그것의 있는 그대로의 모습을 포착하는 절대의 인식 방법을 통해 실현된다. 그러나 지각의 확장을 실천하는 것은 탁월한 예술가나 철학자들만의 전유물이 아니다. 베르그손의 지각론이 알려주는 바, 우리 각자가 지각하는 세계의 축소와 확장을 관장하는 것은 어디까지나 스스로의 시선 여하에 달려 있기 때문이다. 본고는 논의의 끝에서 평범한 사람들인 우리가 무용한 것에의 주목을 통해 자신의 삶을 보다 풍성한 것으로 만드는 적극적인 실천가가 될 수 있다는 그 가능성을 확인할 것이다.들어가며 1 1. 동일한 대상이 달리 지각되는 현상 1 2. 베르그손의 지각론에 대한 소고 6 3. 비일상적 지각 경험에 대한 접근 방향 9 4. 기대 효과 및 최종적인 목적 13 I. 지각의 가변성 16 1.1 지각의 구성요소들 16 1.1.1 물질성을 담보하는 순수지각 18 1.1.2 물질과 정신을 이어주는 수축기억 22 1.1.3 지각의 질감을 결정하는 이미지-기억 28 1.2 지각 속 기억의 메커니즘 37 1.2.1 잠재된 기억의 호출 37 1.2.2 기억의 호출을 이끄는 이중 운동 42 1.2.3 이중 운동이 일어나는 정신의 상이한 기조들 45 1.3 기억과 지각의 상호 작용 52 1.3.1 기억과 지각의 연쇄적인 순환 52 1.3.2 기억과 지각의 순환이 가능한 이유 57 II. 지각의 확장 63 2.1 지각의 축소와 확장을 주재하는 정신의 주의 63 2.1.1 생의 유지에 필수적인 삶에의 주의 64 2.1.2 차이의 기억을 호출하는 반성적 주의 73 2.1.3 반성적 주의의 비의지성 및 앙양 98 2.2 반성적 주의를 통한 지각의 확장 106 2.1.1 보이지 않던 것을 지각하는 경험 107 2.2.2 8자 도식을 통해 살펴보는 지각의 확장 112 III. 지각의 확장의 실천 119 3.1 지각의 확장의 범례, 예술과 철학 119 3.1.1 지각의 확장으로서의 예술 121 3.1.2 지각의 완성으로서의 철학 128 3.2 지각의 확장과 직관 135 3.2.1 분석과 직관 136 3.2.2 지각의 확장과 직관의 실행 142 3.3 지각의 확장과 삶 150 3.3.1 지각의 확장의 필요성 151 3.3.2 지각의 확장의 실천 가능성 155 나가며 160 1. 의의 및 한계 160 2. 제기될 수 있는 문제들 166 3. 무용한 것의 가치 173 참고문헌 176 Abstract 179Maste

Increased Sclerostin Level after Further Ablation of Remnant Estrogen by Aromatase Inhibitors

BACKGROUND: Sclerostin is a secreted Wnt inhibitor produced almost exclusively by osteocytes, which inhibits bone formation. Aromatase inhibitors (AIs), which reduce the conversion of steroids to estrogen, are used to treat endocrine-responsive breast cancer. As AIs lower estrogen levels, they increase bone turnover and lower bone mass. We analyzed changes in serum sclerostin levels in Korean women with breast cancer who were treated with an AI. METHODS: We included postmenopausal women with endocrine-responsive breast cancer (n=90; mean age, 57.7 years) treated with an AI, and compared them to healthy premenopausal women (n=36; mean age, 28.0 years). The subjects were randomly assigned to take either 5 mg alendronate with 0.5 μg calcitriol (n=46), or placebo (n=44) for 6 months. RESULTS: Postmenopausal women with breast cancer had significantly higher sclerostin levels compared to those in premenopausal women (27.8±13.6 pmol/L vs. 23.1±4.8 pmol/L, P0.05). CONCLUSION: Serum sclerostin levels increased with absolute deficiency of residual estrogens in postmenopausal women with endocrine-responsive breast cancer who underwent AI therapy with concurrent bone loss.ope

조기 만성신질환 환자에서 근육량과 골밀도, 비타민 D의 연관성

의과대학/석사We previously identified that chronic kidney disease (CKD) stage 3 was strongly associated with sarcopenia. However, few studies have investigated sarcopenia in early-stage CKD. This study was designed to determine the prevalence of sarcopenia and analyze the factors associated with low skeletal muscle mass by focusing on bone mineral density (BMD) in early-stage CKD population. This cross-sectional study included the participants aged ≥55 years from the Korea National Health and Nutrition Examination Survey 2008？2010. As results, the prevalence of sarcopenia was 30.0% in control group and 38.4% in CKD in men. In control group, total hip BMD, serum vitamin D, insulin resistance, and total energy intake were associated with skeletal muscle mass in men, while total hip BMD, vitamin D, and total energy intake were associated with skeletal muscle mass in women. Meanwhile, in CKD group, only total hip BMD was associated with muscle mass in men, while total hip BMD and vitamin D level were associated with muscle mass in women. In conclusion, low hip BMD and low serum vitamin D levels are closely associated with low skeletal muscle mass in patients with early-stage CKD.ope

불소가 편입된 키토산 나노입자의 불소유리에 관한 연구

학위논문(석사) --서울대학교 치의학대학원 :치의학과,2010.2.Maste

The contribution of body burden by food exposure using dioxin in blood concentrations and simulation models

prohibition석

시간적 클러스터링을 활용한 퓨샷 시계열 이상치 탐지

학위논문(석사) - 한국과학기술원 : 김재철AI대학원, 2023.8,[iv, 43 p. :]Time-series anomaly detection is a study that finds unusual data in a series of observed, chronologically listed data. Anomaly detection in time-series data has become an important task in many applications. It can provide valuable insights into the underlying process or system being monitored, helping to prevent catastrophic events, reduce costs, and improve overall efficiency. As time-series data becomes increasingly complex and larger, there are some limitations in the quality of time-series data, such as a lack of labels, inaccurate labels, and contamination of training data. Therefore, in this work, we propose to cluster dimensions of multivariate time series into meaningful groups to train anomaly detection models for each cluster. We also take advantage of a few anomaly labels included in the training dataset to proceed with this process. We confirm that real-world data can be separated into several groups that share similar patterns and that, in fact, anomaly detection performance increases when the model is trained for each cluster.한국과학기술원 :김재철AI대학원

Concurrent bisphosphonate-related bilateral atypical subtrochanteric fractures and osteonecrosis of the jaw on bone scintigraphy

An 82-year-old woman presented with bilateral thigh pain. She had pain in her right thigh operated for a low-trauma fracture 2 years earlier and newly developed pain in her left thigh without trauma. A whole-body bone scan revealed increased tracer uptake in her bilateral subtrochanteric femoral shafts and in the right mandible without evidence of metastatic bone disease. She had been taking bisphosphonates for 7 years to treat osteoporosis and was soon diagnosed with atypical subtrochanteric fractures and bisphosphonate-related osteonecrosis of the jaw. The bone scan simultaneously identified 2 serious adverse effects of long-term use of bisphosphonates.ope

Gender-specific pleiotropic bone–muscle relationship in the elderly from a nationwide survey (KNHANES IV)

SUMMARY: The aim of this study was to examine the gender-specific association between sarcopenia and bone geometry/metabolic parameters. Low muscle mass was associated with greater deterioration of bone than in deterioration of glucose or lipid profiles. This bone-muscle relationship was more prominent in men than in women. INTRODUCTION: There are few studies that report on gender differences in the effects of low muscle mass on bone and metabolic parameters in elderly subjects. This study aimed to assess the gender-specific influence of muscle mass on bone and metabolic parameters. METHODS: A total of 2,264 participants (940 men and 1,324 women) whose age ranged from 65 to 92 years were analyzed using data from The Fourth Korea National Health and Nutrition Examination Surveys (2008-2009). We measured bone mineral density (BMD) and appendicular muscle mass using the dual-energy X-ray absorptiometry and also measured metabolic profiles. RESULTS: The age-related trend in bone and muscle coincided in men but not in women. Femoral neck (FN) and total hip (TH) BMD were highly correlated with muscle mass in both genders. However, in women, this correlation was not significant in the lumbar spine (LS). In addition, this positive correlation was stronger in the FN or TH than in the LS and was stronger in men than in women. Subjects with sarcopenia were at a higher risk for osteoporosis in the FN, TH, and LS in men, and in the TH and FN in women. The degree of association between muscle mass and metabolic profiles was relatively very weak. CONCLUSION: Bone-muscle relationship was more prominent in men than in women. The gender differences in bone-muscle relationship may be helpful for the development of gender-specific preventive strategies in the elderly, especially in men.ope

Early-stage chronic kidney disease, insulin resistance, and osteoporosis as risk factors of sarcopenia in aged population: The Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV), 2008–2009

Sarcopenia means the progressive loss of skeletal muscle mass and strength with aging. In this study, we found that insulin resistance, chronic kidney disease stage 3, and osteoporosis at the femur neck were closely associated with sarcopenia in elderly men. These conditions modified to slow down the progression of sarcopenia. INTRODUCTION: Sarcopenia is known to have multiple contributing factors; however, its modifiable risk factors have not yet been determined. The aim of this study was to identify the most influential and modifiable risk factors for sarcopenia in elderly. METHODS: This was a population-based, cross-sectional study using data from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV), 2008-2009. This study included 940 men and 1,324 women aged 65 years and older who completed a body composition analysis using dual-energy X-ray absorptiometry. Sarcopenia was defined as an appendicular skeletal muscle mass divided by height(2) of less than 1 standard deviation below the sex-specific mean for a younger reference group. RESULTS: Using univariate analysis, age, body mass index (BMI), homeostasis model assessment for insulin resistance (HOMA-IR), limitations in daily activities, regular exercise, high-risk drinking, family income, osteoporosis, daily energy, and protein intake were associated with sarcopenia in men; age, BMI, limitations in daily activities, regular exercise, occupation, osteoporosis at the total hip, and daily energy intake were associated with sarcopenia in women. In the multivariate logistic regression analysis, HOMA-IR ≥2.5 (odds ratio [OR] for sarcopenia, 2.27; 95 % confidence interval [CI], 1.21-4.25), chronic kidney disease stage 3 (OR, 3.13; 95 % CI, 1.14-8.61), and osteoporosis at the femur neck (OR, 6.83; 95 % CI, 1.08-43.41) were identified as risk factors for sarcopenia in men. CONCLUSIONS: Insulin resistance, chronic kidney disease, and osteoporosis at the femur neck should be modified to prevent the acceleration of skeletal muscle loss in elderly men.ope