Organ culture of tooth bud transplanted in the mouse mandibular none tooth bearing diastema

Thesis (master`s)--서울대학교 대학원 :치의학과 구강악안면외과학전공,2004.Maste

우리나라 암 연구수준의 평가와 암 연구인력 훈련요구의 예측 : 델파이법의 적용

학위논문(석사)--서울대학교 대학원 :의학과 의료관리학전공,1998.Maste

Relationship between percutaneous transluminal coronary angioplasty volume and immediate outcome

학위논문(박사)--서울대학교 대학원 :의학과 의료관리학전공,2000.Docto

Strategies to reduce risk factors of non-communicable diseases in South Korea

Objectives: This review is to suggest strategies to reduce risk factors of non-communicable diseases (NCD) in South Korea. Methods: Prior research findings on the burden of NCD and associated risk factors and the effectiveness of intervention programs were reviewed. Strategies regarding the control of NCD risk factors were conceived. Results: The author presented research findings from the Global Burden of Disease study on the burden of non-communicable disease (NCD) and associated risk factors in South Korea. Strengths and limitations of population and high-risk strategies for preventing NCDs were introduced. The author also reviewed the evidence on the effectiveness of multiple cardiovascular risk factor interventions and community-based intervention programs on cardiovascular diseases conducted in industrialized countries. Finally, strategies to reduce NCD risk factors in South Korea were suggested. Conclusions: The evidence-based interventions and the importance of population strategies in NCD prevention were highlighted. The author indicated that strategies employed by unhealthy commodity industries to undermine effective public health policies and programs should be actively monitored. It has been suggested that effective high-risk strategies with ecological models to address social risks rather than medical risks among disadvantaged population should be further developed in South Korea.N

산화물 반도체의 광학 및 전기적 성질에 관한 제일원리 계산 연구

학위논문 (박사)-- 서울대학교 대학원 : 재료공학부, 2015. 8. 한승우.Oxide semiconductor (OS) is a promising candidate for the application to large-area and flexible opto-electrical devices, because OS which is deposited at low temperature exhibits the outstanding electrical properties showing the high electron mobility (~10 cm2/Vs) in comparison with the widely used semiconductors such as amorphous Si (a-Si). In addition, since OS is transparent in the most visible and near-infrared regions due to their large band gap, it is often called transparent oxide semiconductor and can be expected to offer a solution for fabrication of the transparent electronic device on flexible substrates. In spite of the advantages of OS, previous experimental studies reported various obstacles to be overcome for realization of the device utilizing OSs. For example, the OS based thin film transistor (TFT) suffers from device instabilities under illumination and bias stress. In addition, the underlying mechanism for the charge transport in OS still remains unclear, which hinders improvement of the OS based device performance. In this research, we investigate the optical and electrical properties of OSs using ab-initio calculations on the basis of density functional theory (DFT) to suggest the strategy to improve the performance of OSs in terms of electron transport and reliability. First, in order to investigate the electron transport in OSs, we introduce the model Hamiltonian for the conduction band within tight-binding approximation and carry out the calculation of the electron mobility considering several types of scattering processes. It is found that the interaction between metal s and oxygen p orbitals under tetrahedral and octahedral local atomic structure gives the quasi-linear dispersion of the conduction band which plays an important role in determining the electron mobility in OSs. In addition, we reveal that the electron mobility in a multi-component OS like InGaZnO4 is dominated by the cation-disorder scattering process. Next, we investigate the influence of hydrogen impurity in OS. Previously, various models to explain the threshold voltage shifts under illumination and bias stress were suggested based on oxygen vacancy defect, but the clear mechanisms for that are still controversial. In this study, the DFT calculation results turn out that hydrogen in OSs can have +1/-1 charge state depending on Fermi level. This bistability of hydrogen enables to cause the threshold voltage shift by alternating its charge state under illumination and bias stress. In a second part, the optical properties are mainly dealt with. For the more realistic modelling, we study the ab-initio calculation methodology based on GW approximation for obtaining the accurate band gap of OS. The DFT calculation usually results in 30~40% underestimation of the band gap in typical insulator and GW method improves the accuracy of the calculated band gap by correcting exchange-correlation energy of the conventional DFT calculation. However, previous GW calculation results for OSs still yield ~10% lower band gap than experimental value. Thus, we investigate the theoretical reason for such wrong description of GW method for OSs and suggest new method to further improve the predictive power of GW method, which shows the mean absolute relative error (MARE) of ~3%. Finally, we study the visible light absorption of amorphous In-Ga-Zn-O since the device degradation critically occurs when exposed to visible and UV light. It is found that the relative downshift of the conduction band position comparing to that of crystalline phase occurs as well as long tail states near the valence band edge appear in amorphous phase. This is one of the main reasons for amorphous OSs to absorb the visible light without any defects.Abstract ························································································ Contents ······················································································· List of table and figures ·························································· 1. Introduction ···········································································1 1.1 Overview of oxide semiconductor (OS) ····························································1 1.2 Challenges in utilization of OS ··········································································6 1.2.1 Transport mechanisms in OS ····································································6 1.2.2 Degradation phenomena in OS device ··················································10 1.3 Goal of the dissertation ·····················································································13 1.4 Organization of the dissertation ······································································17 1.5 Bibliography ··········································································································18 2. Theoretical background ···················································20 2.1 Density functional theory (DFT) ······································································20 2.1.1 Hohenberg and Kohn theorem ································································20 2.1.2 Kohn-Sham equation ·················································································23 2.2 Exchange-correlation energy ············································································26 2.2.1 Local density approximation (LDA) ························································26 2.2.2 Generalized gradient approximation (GGA) ··········································29 2.3 Beyond the DFT ··································································································31 2.3.1 DFT+U ··········································································································31 2.3.2 Hybrid functional ························································································33 2.3.3 GW approximation ·····················································································37 2.4 Electron transport ·······························································································40 2.4.1 Fermi-Golden rule ·····················································································40 2.4.2 Boltzmann transport equation ·································································43 2.5 Optical absorption in insulator ·········································································45 2.6 Defect formation energy ···················································································47 2.7 Bibliography ··········································································································49 3. Electronic property of OS ··············································50 3.1 Introduction ···········································································································50 3.2 Calculation method ······························································································51 3.3 Results and discussion ························································································54 3.3.1 Quasi-linear band structures in OS ·······················································54 3.3.2 Electron mobility in crystalline ZnO ·····················································65 3.3.3 Electron mobility in crystalline In-Ga-Zn-O (IGZO) ··························68 3.3.4 Hydrogen defect in In-Zn-Sn-O (IZTO) ···············································76 3.4 Bibliography ··········································································································86 4. Optical property of OS ····················································88 4.1 Introduction ···········································································································88 4.2 Calculation method ······························································································89 4.3 Results and discussion ························································································93 4.3.1 Band gap of OS in GW approximation ·················································93 4.3.2 Optical absorption of crystalline and amorphous IGZO ··················101 4.4 Bibliography ········································································································109 5. Conclusion ·········································································111 국문초록 ·················································································114Docto

조직재생을 위한 비계 및 성장인자 저장고로서 혈소판 풍부 피브린의 역할

학위논문 (박사)-- 서울대학교 대학원 : 치의학과 구강악안면회과학 전공, 2011.2. 정필훈.Docto

COMPTER SYSTEM FOR AUTOMATIC EXPLORATION OF MENTAL ILLNESS DIAGNOSIS PROTOCOL AND METHOD THEREOF

다양한 실시예들은 정신 질환 진단 프로토콜 자동 탐색을 위한 컴퓨터 시스템 및 그의 방법에 관한 것으로, 제 1 인공 신경망을 기반으로, 환자의 뇌 영상에서 미리 정해진 정신 질환 진단을 위해 검사되어야 할 적어도 하나의 검사 영역을 결정하고, 제 2 인공 신경망을 기반으로, 환자에 대해 정신 질환 진단을 위한 검사 프로세스를 결정하고, 검사 영역과 검사 프로세스를 기반으로, 환자에 대해 정신 질환 진단을 위한 검사 프토로콜을 제공하도록 구성될 수 있다. 다양한 실시예들에 따르면, 컴퓨터 시스템은 뇌 영상에서 검사 영역의 위치, 형상, 크기 또는 중요도 중 적어도 하나를 시각화할 수 있다. 다양한 실시예들에 따르면, 검사 프로세스는 정신 질환 진단을 위해 뇌 영상이 활용되어야 할 복수의 검사 스테이지들의 진행 순서를 포함할 수 있다

Motherhood as Experienced by Women in a Prenatal and Early-Childhood Home Visitation Program, and Associated Factors

Purpose: This study is intended to examine the difficulties facing mothers of young children (early childhood) and to understand the associated factors. Method: We analyzed 1,003 data items of women with children under age 2 who participated in a prenatal and early-childhood home visitation program in Seoul from 2016 to 2019. For our research, we used self-administered registration and service monitoring data. The difficulties the women faced as mothers were measured using the Being a Mother Scale (BaM-13). This analysis considered covariates including maternal and infant ages, their number of children, economic conditions, presence of disabilities, single motherhood, multicultural migration background, employment status, unintended pregnancy, instrumental and emotional support, and depression scores. Results: The average score for being a mother was 14.45 (standard deviation=6.61), and higher scores were recorded for women with spouses, Korean women (as opposed to multicultural immigrant women), women whose pregnancies were unplanned, women without instrumental support, and severely depressed women. Conclusion: Motherhood poses great difficulties to women with children under age two. To help women transition from motherhood, it is important to understand their situations in relation to their social and psychological characteristics, as well as the cultural, social, and contextual perspectives they bring to motherhood.N

Encephalocele(Two Autopsy Cases Report)

Two autopsy cases of encephaloceles were reported. The first case was a female baby died in one day and had a huge occipital mass containing posteri"r two thirds of cerebrum. midbrain, pons and medulla oblongata. An unexplained polypoid mass of cerebral tissue was seen at parasagittal area of left parietal lobe. Tentorium cere belli was absent. Subarachnoid vessels were congested. The encephalocele was covered by dura and skin. Occipital bone had a huge defect. The subcutaneous tissue over the encephalocele had multiple nests of neuroglial cells without connection to the brain proper. Cut sections of the brain showed enlargement of left lateral ventricle. Focal hemorrhage and calcification were present at occipital lobe. The second case was a female baby died soon after birth. She had a cystic, polypoid mass at right forehead. Right eye was replaced downward and nares were separated apart. Median cleft lip was also present. Right half of frontal bone was completely defective, a small portion of through which frontal lobe was herniated. Cystic cavity of the frontal mass was a continuation of right lateral ventricle. Falx cerebri was hypoplastic, thalami fused to each other and Arnold-Chiari type I anomaly was associated. Cut sections showed bilateral hydrocephalus especially at right lateral ventricle. The encephalocele was covered by skin and dura. Skeletal muscle was partly incooperated and was splitted. Anterior lobe of pituitary gland showed abnormal capsulation with fibre-collagenous capsule and septation. Classical theories explaining the pathogenesis of encephaloceles were proposed by Geoffrey-SaintHillaire( 1827) and Spring(l853). They were incomplete separation of ectodermal germ layers and increased intracranial pressure. But disputes on the pathogenesis are still present. Major disputes are summarized as: 1. Whether the brain tissue in encephalocele is herniated tissue or heterotopic tissue? 2. Is there any evidence explaining the classical theory of Geoffrey-Saint- Hillaire? 3. Is the increased intracranial pressure a primary defect or secondary phenomenon? 4. Local ischemia in skull and adjacent soft tissue makes the defect to give harniating pathway, is it true? We reviewed the literature and tried to explain them based on the findings of our cases

Anesthetic Management of the Oral and Maxillofacial Surgery in a Patient with End-Stage Renal Disease -A case report -

Patients in end-stage renal disease (ESRD) and chronic renal failure present a number of challenges to the anesthesiologist. They may be chronically iii and debilitated and have the potential for multiorgan dysfunction. A 65-year-old male patient with ESRD was scheduled for oral cancer surgery under general anesthesia. He was in regular hemodialysis three times a week and secondary hypertension with left ventricular hypertrophy was accompanied. He also had chronic metabolic acidosis and hyperkalemia. The day after hemodialysis, general anesthesia was carried out. Uneventful anesthetic induction using thiopental and vecuronium and nasotracheal intubation were carried out. General anesthesia was maintained with isoflurane for 9 hours. During the anesthesia, he did not have any problem but persistently increasing serum potassium level. After anesthetic emergence, he was transferred to intensive care unit for mechanical ventilation. So we report this successful case of anesthetic management in a patient with ESRD for oral cancer surgery, which massive bleeding and long anesthetic time were inevitable in, from the preoperative preparation to anesthetic emergence