Effect of canine cortical bone demineralization on osteogenic differentiation of adipose-derived mesenchymal stromal cells

학위논문 (석사)-- 서울대학교 대학원 수의과대학 수의학과, 2017. 8. 권오경.Demineralized bone allografts and mesenchymal stromal cells have been used to promote bone regeneration. However, the degree to which cortical bone should be demineralized for use in combination with adipose-derived mesenchymal stromal cells (Ad-MSCs) remains to be clarified. In this study, the in vitro osteogenic ability of Ad-MSCs on allografts was investigated in relation to the extent of demineralization. Three treatment groups were established by varying exposure time to 0.6 N HCL: partially demineralized (PDB12 h), fully demineralized (FDB48 h), and non-demineralized bone (NDB0 h, as a control). Allografts were prepared as discs 6 mm in diameter for in vitro evaluation, and their demineralization and structure were evaluated by micro-computed tomography and scanning electron microscopy. Ad-MSC adhesion and proliferation were measured by MTS assay, and osteogenesis-related gene expression was assessed by quantitative reverse transcription polymerase chain reaction. PDB and FDB demineralization rates were 57.13 and 92.30 %, respectively. Moreover, Ad-MSC adhesion rates on NDB, PDB, and FDB were 53.41, 60.65, and 61.32 %, respectively. Proliferation of these cells on FDB increased significantly after 2 days of culture compared to the other groups (P < 0.05). Furthermore, expression of the osteogenic genes ALP, BMP-7, and TGF-β in the FDB group on culture day 3 was significantly elevated in comparison to the other treatments. Given its biocompatibility and promotion of the osteogenic differentiation of Ad-MSCs, our results suggest that FDB may be a suitable scaffold for use in the repair of bone defects.I. INTRODUCTION 1 II. MATERIALS AND METHODS 3 1. Bone harvesting and demineralization 3 2. Isolation and culture of Ad-MSCs 4 3. Cell seeding 5 4. MTS assays 6 5. Micro-computed tomography 7 6. Scanning electron microscopy 7 7. Real time polymerase chain reaction 8 8. Statistical analysis 10 III. RESULTS 11 1. Demineralized bone morphology 11 2. Ad-MSC adherence to and proliferation on bone discs 13 3. Osteogenic gene expression in Ad-MSCs 16 IV. DISCUSSION 18 V. REFERENCES 21 VI. ABSTRACT IN KOREAN. 25Maste

Cho, Kwang Rae

학위논문(석사)--아주대학교 정보통신대학원 :사이버보안,2020. 2사이버 공격은 DDoS, 홈페이지 위·변조, 악성코드 유포 공격 등 다양하게 이루어지고 있다. 그 중 악성코드 유포 공격은 집단 규모가 커지고 점차 조직화 되고 있으며 PC, 스마트폰 등에 대한 사이버 공격 피해 사례가 늘어나고 있다. 또한, 악성코드 유포 속도에 비해 탐지 속도가 뒤처지고 있어 효과적인 대응이 이루어지지 못하는 실정이다. 이에 따라 다양한 분야에서 악성코드 탐지를 위한 딥러닝 및 머신러닝 기법을 이용한 연구가 활발히 진행되고 있다. 그 중 CNN(Convolutional Neural Network)를 이용한 악성코드 분류의 정확도는 기존의 분류방법보다 정확도가 높은 것을 알 수 있다. 본 논문에서는 수집한 악성코드를 대상으로 CNN을 이용하여 바이트 코드 전체를 입력데이터로 하는 방법과 중요 섹션만을 추출하여 입력데이터로 사용한 방법을 실험을 통해 비교한 결과 중요 섹션만을 추출한 유형 분류의 정확도가 더 향상된 것을 확인하였다.제 1 장 서론 ········· ············1 제 1 절 연구 배경 및 목적 ··············1 제 2 절 연구의 구성 ·················4 제 2 장 머신러닝 및 딥러닝 기술 ············5 제 1 절 머신러닝(Machine Learning) ··········5 1. 지도 학습(Supervised Learning) ··········6 2. 비지도학습(Unsupervised Learning) ········8 3. 강화학습(ReinForcement Learning) ········8 제 2 절 딥 러닝(Deep Learning) ············9 1. 인공신경망(Artificial Neural Network) ·······9 2. 퍼셉트론(Perceptron) ··············10 제 3 절 합성곱 신경망(Convolutional Neural Network)····12 1. 합성곱 계층(Convolution Layer) ·········13 2. 풀링 계층(Pooling Layer) ············14 3. 활성화 함수··················14 제 3 장 기존 악성코드 탐지 및 분석 기술 ·······15 제 1 절 악성코드 ·················15 제 2 절 악성코드 분석 방법 ·············16 1) 자동화 분석(Fully-automated analysis) ······17 2) 정적 분석(Static Analysis) ············17 3) 동적 분석(Dynamic Analysis) ··········18 4) 상세 분석(Manual code reversing) ········18 제 3 절 딥러닝 기반 악성코드 연구 ··········19 제 4 장 제안하는 악성코드 식별 및 유형 분류 방법 ···21 제 1 절 실험 환경 ·················22 제 2 절 샘플 파일 ·················22 제 3 절 실험 절차 ················23 1) 악성코드 이미지 변환 ············23 2) 학습, 검증 데이터셋 구축 ··········26 3) 신경망 구축 ·················27 제 4 절 실험 결과 ·················29 제 5 장 결 론 ····················31 참고문헌 ·······················32Maste

Predictive value of C-reactive protein for major postoperative complications following off-pump coronary artery bypass surgery: prospective and observational trial

BACKGROUND: To prospectively investigate the predictive value of the preoperative C-reactive protein (CRP) concentration for major postoperative complications following off-pump coronary artery bypass (OPCAB) surgery. METHODS AND RESULTS: From January 2007 to December 2007, 185 consecutive patients scheduled for elective OPCAB surgery were allocated to a low-CRP group (n=137, CRP or = 0.3 mg/dl). The incidence of major postoperative complications, defined as postoperative myocardial infarction, and 5 major morbidity endpoints including permanent stroke, renal dysfunction, any cardiac surgery reoperation, ventilation for more than 48 h, and deep sternal wound infection were assessed and compared. Multivariate logistic regression was used to determine the predictors of major postoperative complications. Patients in the high-CRP group had a significantly higher overall incidence of major postoperative complications, particularly renal dysfunction. In the multivariate logistic regression model, adjusting all the significant univariate predictors, baseline CRP >0.3 mg/dl and preoperative chronic renal failure (CRF) remained as significant independent predictors of major postoperative complications. CONCLUSIONS: Elevated preoperative CRP level and/or preoperative CRF indicate increased risk of developing major postoperative complications, particularly acute postoperative renal dysfunction in patients undergoing OPCAB surgery.ope

DEVELOPMENT OF LANGMUIR AND ELECTRON PROBE FOR KSR-III

한국항공우주연구원에서는 지난 1998년 KSR-2 촤학로켓에 이온층 전자환경 측정기를 탑재하여 한반도 상공의 전자 밀도, 전자 온도, 부동 전위등을 측정하는데 성공하였다. 이온층 전자환경 측정기는 한반도 상공 이온층의 전자 온도와 밀도를 측정하는데 목적이 있다. 이번 연구에서는 2002년 상반기 발사 예정인 KSR-3 과학로켓에 탑재될 전자환경 측정기를 개발하였고 일본에서 우주 환경 모사 실험을 수행하여 측정기의 성능을 확인하였다. 전자환경 측정기는 랑뮈어 프로브(Langmuir Probe)와 전자 온도 프로브(Electron Temperature Probe)로 구성되어 있으며 이 센서들의 측정 결과로부터 이온층의 전자 밀도와 온도에 대한 정보를 얻을 수 있다. 이렇게 개발된 전자환경 측정기로부터 신뢰성 있는 자료를 얻는다면 IRI(International Reference Ionosphere) 모델이나 PIM(Parameterized Ionospheric Model)과 비교하여 한반도 상공의 이온층 전자 환경에 대한 이해를 돕는데 기여할 수 있을 것으로 기대된다. KARI(Ko.ea Aerospace Research Institute) has measured the ionospheric electron temperature and density over the Korean Peninsular with the Langmuir and Electron Probe(LEP) onboard the Korean Sounding Rocket-II(KSR-II) In 1998. The purpose of LEP is to measure the electron density and temperature profile in the ionosphere. LEP consists of the Langmuir probe(LP) and the Electron temperature Probe(ETP) which are widely used for the measurement of the ionospheric plazma environment . We discuss the development of the Langmuir and Electron Probe which will be onboard the KSR-III and some test results in a simulated space plasma environment with the plasma chamber at the ISAS in Japan. These measurements could contribute to the basic study of ionospheric environment which also can be compared with other reference models such as IRI and PIM.22Nkc