Vietoris-Rips complex의 최소 표본점과 persistence에 대하여

학위논문(박사) -- 서울대학교대학원 : 자연과학대학 수리과학부, 2021.8. Otto van Koert.최근 위상적 자료분석 방법은 데이터 분석에 각광받고 있다. 이 논문에서는 데이터의 모형을 분석하기 위하여 Vietoris-Rips complex와 persistent 호몰로지를 연구하였다. 특별히, Vietoris-Rips complex구조가 주어진 데이터가 n차원 구와 같은 호몰로지를 갖을 수 있다고 할 때, 필요한 최소한의 데이터 양을 산출해냈다.Recently topological data analysis become a popular tool to analyze data. In this paper, we study the behaviour of Vietoris-Rips complex with persistent homology to figure out the shape of data. In particular, we find the minimal number of data points on a sphere such that homology of the Vietoris-Rips complex of those data points is isomorphic to the homology of the sphere.1 Introduction 1 2 Preliminaries 4 2.1 Nerve theorem with Vietoris-Rips complex 15 3 Persistence 17 3.1 Persistent homology 17 3.1.1 Tameness and barcodes 19 3.2 The Isometry theorem 25 4 2n-problem 29 4.1 Examples 30 4.2 Minimal Construction for S^2 33 4.3 Another proof of Minimal Construction for S^2 42 4.4 6 points probability for S^2 44 4.4.1 Script for 6 points probability 44 4.4.2 Bootstrap Con fidence Intervals 47 4.5 Vietoris-Rips complex for S^n 49 5 The Vietoris-Rips complex on a circle S^1 53 6 Reliable barcodes 59 6.1 On the length of barcodes 59 6.1.1 Mission impossible 60 6.1.2 Basic assumptions 61 6.1.3 Further assumptions 61 6.1.4 Convex balls and curvature 62 6.1.5 Background from metric geometry 65 6.1.6 Persistent homology of the Vietoris-Rips complex 67 6.2 Application to data 67 6.2.1 Revisiting the cube 68 6.2.2 Discretized curvature 69 7 Appendix 73 7.1 Notation and Conventions 73 7.2 Background from Probability 78 7.3 Scripts to compute persistent homology 82 Bibliography 84 Abstract (in Korean) 87박

Tongue Volume Influences Lowest Oxygen Saturation but Not Apnea-Hypopnea Index in Obstructive Sleep Apnea

OBJECTIVES: The aim of this study was to identify correlations between sleep apnea severity and tongue volume or posterior airway space measured via three-dimensional reconstruction of volumetric computerized tomography (CT) images in patients with obstructive sleep apnea (OSA) for use in predicting OSA severity and in surgical treatment. We also assessed associations between tongue volume and Mallampati score. METHODS: Snoring/OSA male patients (n = 64) who underwent polysomnography, cephalometry, and CT scans were enrolled in this retrospective study. OSA was diagnosed when the apnea-hypopnea index (AHI) was greater than 5 (mild 5-14; moderate 15-29; severe>30). The patients were also categorized into the normal-mild group (n = 22) and the moderate-severe group (n = 42). Using volumetric CT images with the three-dimensional reconstruction technique, the volume of the tongue, posterior airway space volume, and intra-mandibular space were measured. The volumes, polysomnographic parameters, and physical examination findings were compared, and independent factors that are related to OSA were analysed. RESULTS: No associations between tongue volume or posterior airway space and the AHI were observed. However, multivariate linear analyses showed that tongue volume had significantly negative association with lowest O2 saturation (r = 0.365, p = 0.027). High BMI was related to an increase in tongue volume. Modified Mallampati scores showed borderline significant positive correlations with absolute tongue volume (r = 0.251, p = 0.046) and standardized tongue volume (absolute tongue volume / intramandibular area; r = 0.266, p = 0.034). Between the normal-mild and moderate-severe groups, absolute tongue volumes were not different, although the standardized tongue volume in the moderate-severe group was significantly higher. CONCLUSION: Absolute tongue volume showed stronger associations with lowest O2 saturation during sleep than with the severity of AHI. We also found that high BMI was a relevant factor for an increase in absolute tongue volume and modified Mallampati grading was a useful physical examination to predict tongue size.ope

Robot-Assisted Neck Dissection via a Transaxillary and Retroauricular Approach Versus a Conventional Transcervical Approach in Papillary Thyroid Cancer with Cervical Lymph Node Metastases

Background: Recently, robot-assisted neck dissection (ND) using a transaxillary approach in thyroid cancer patients with lateral neck metastases (LNM) was demonstrated to be feasible. The aim of this study was to compare the surgical outcomes of a modified transaxillary and retroauricular (TARA) versus a conventional transcervical approach in papillary thyroid carcinoma (PTC) patients with LNM. Patients and Methods: In total, 47 patients with PTC underwent total thyroidectomy with central compartment ND and modified radical ND except Level I. Twenty-two NDs were performed via the TARA approach, and 25 unilateral NDs were performed via the conventional transcervical approach. Results: The TARA and the open ND groups consisted of 22 and 25 patients, respectively. The operation time for ND in the TARA group was longer than that in the open ND group (209.4±38.2 minutes versus 143.1±30.5 minutes; P=.000). The mean scar satisfaction score in the TARA group was higher than in the conventional ND group (3.9±1.0 versus 2.8±1.0; P=.000). There were no differences in the mean number of retrieved lymph nodes. Conclusions: The robot-assisted ND via the TARA approach can be an alternative option that produces excellent esthetic results for the management of LNM in PTC patients.ope

Analysis of Acrylamide Contents in Processed Foods from Korean Market and Estimation of Individual Exposure Using a Non-parametric Probabilistic Model

학위논문(석사)--서울대학교 대학원 :생활과학대학 식품영양학과,2020. 2. 권훈정.발암물질인 아크릴아마이드는 환원당과 아스파라긴을 함유한 식품을 조리할 때 생성된다. 일반인에서 아크릴아마이드의 주된 노출 경로는 식품이므로, 2017년 유럽에서 식품 내 아크릴아마이드의 잔류허용치를 설정하였다. 또한 2016년 한국 총식이조사(total diet study) 연구에서 아크릴아마이드는 23종의 가공 중 생성되는 유해물질 중에서 노출안전역(margin of exposure)이 가장 낮게 보고되어, 아크릴아마이드의 위해 저감이 필요하게 되었다. 따라서 본 연구의 목적은 각 식품유형별 아크릴아마이드 수준을 파악하여, 관리가 가능한 식품 유형을 규명하는 것이다. 아크릴아마이드 분석에는 고성능 액체 크로마토그래피와 텐덤 질량분석기(HPLC-MS/MS)를 이용하였으며, 1,000 건 이상의 가공식품을 분석하였다. 가공식품을 통한 아크릴아마이드의 노출량 추정에는 본 연구의 분석 결과와 2013~2017년도의 국민건강영양조사의 식품 섭취 자료를 사용하였으며, 확률론적 방법의 non-parametric technique을 적용하였다. 분석 결과, 감자 과자를 포함한 과자류에서는 아크릴아마이드가 넓은 범위에서 나타났으며, 돼지감자로 만든 차에서 가장 높은 수준의 아크릴아마이드가 검출되었다. 또한 돼지감자와 강황에서의 아크릴아마이드가 본 연구에서 최초로 밝혀졌다. 주된 노출 기여식품은 3~18세의 미성년자에서는 과자류였으며, 19~80세의 성인에서는 커피였다. 따라서 과자류와 커피에서의 위해 관리방안이 강구된다면 한국인의 아크릴아마이드 노출을 저감하는데 도움이 될 것이다. 또한 특정 식품을 선호하는 소비자들의 아크릴아마이드 노출을 관리하기 위하여, 돼지감자 차와 같이 높은 아크릴아마이드를 함유하고 있는 식품에 대한 저감화 방안이 필요할 것으로 사료된다.Acrylamide, a known carcinogen, is formed during preparation of food containing reducing sugar and asparagine. Because acrylamide exposure to the population is primarily through food, the maximum levels of acrylamide in food have been set by European Commission in 2017. Moreover, in the 2016 Korean Total Diet study, acrylamide showed the lowest margin of exposure among 23 food-processing-related chemicals, necessitating the risk reduction options. Therefore, the objective of this study was to determine the variation of acrylamide content in different food items and identify the food categories, which can be options for risk management. Acrylamide was analyzed using high performance liquid chromatography coupled with tandem mass spectrometry in more than 1,000 processed food items. To estimate acrylamide exposure, the analytical data obtained herein and the food consumption data of Korean National Health and Nutrition Examination Survey from 2013 to 2017 were used. A non-parametric technique of a probabilistic model was used for exposure estimation. Confectioneries including potato snacks contained a wide range of acrylamide content. Particularly, the highest acrylamide content was detected in a tea made of Jerusalem artichoke. The presence of acrylamide in turmeric along with the Jerusalem artichoke was reported in this study for the first time. The main contributors of dietary acrylamide exposure were confectioneries for youths aged 3–18 years and coffee for adults aged 19–80 years. Therefore, risk management in confectioneries and coffee could help reduce acrylamide exposure for Koreans. In addition, the mitigation strategies for food containing high acrylamide content, such as Jerusalem artichoke tea, are needed to reduce acrylamide exposure to loyal consumers.제 1장 서론 1 제 2장 문헌고찰 3 제 3장 재료 및 방법 10 3.1. 시약 10 3.2. 분석시료 선정 및 구입 11 3.3. 아크릴아마이드 분석법 15 3.4. 신뢰성 확보 22 3.5. 노출량 평가 28 제4장 결과 및 고찰 31 4.1. 신뢰성 확보 31 4.2. 국내 유통 가공식품의 아크릴아마이드 함량 48 4.3. 가공식품 섭취를 통한 아크릴아마이드 노출량 추정 69 제5장 요약 및 결론 81 참고문헌 83 Abstract 91Maste

Symptoms of hemodialysis patients in ED and their self care behavior

응급간호전공/석사[한글] 혈액투석환자는 만성적 질환으로 지속적인 자가간호를 시행하여 스스로 질병을 관리해야 하며 그렇지 않을 경우 합병증의 이환율을 증가시키게 되므로 자가간호수행을 높이기 위한 중재가 요구된다. 본 연구는 응급실에 내원하는 혈액투석환자들의 응급실 방문시 증상과 증상대처 방법 및 자가간호 수행과의 관계를 파악하기 위해 시도되었다. 연구의 대상자는 응급실에 내원한 혈액투석환자로 서울소재 A전문종합요양기관과 A대학병원 응급실에 내원한 환자 총 45명을 대상으로 하였다. 자료수집은 2008년 10월 1일부터 11월 30일까지 2개월간 실시되었으며 구조화된 설문지 및 의무기록검토, 면담을 통하여 자료수집을 하였으며, 자료분석방법은 SAS를 이용하여 백분율, Wilcoxon rank sum test, Kruskal wallis test, Spearman correlation 등의 방법을 사용하여 분석하였다. 본 연구결과는 다음과 같다. 1. 본 연구 대상자의 응급실을 내원한 주증상은 호흡곤란 22.2%, 복통, 복부팽만 13.3%, 현기증, 전신쇠약, 혈압저하 11.1%, 동정맥루 기능이상 11.1%로 나타났고, 최종 진단은 심장질환 24.4%, 감염 24.4%, 혈관질환 11.1%, 신경학적 질환 8.9%였으며 진료결과 62.2%가 입원치료를 필요로 하였다. 2. 연구 대상자의 증상대처 방법은 '응급실을 방문한다' 51.1%, '침상안정을 취하며 경과관찰한다' 15.6%, '약물을 복용한다' 13.3%, '1차 의료기관을 방문한다' 8.9%, '혈당, 혈압을 체크한다' 6.7%, '상처소독과 혈당을 측정한다', '의료기관에 전화하여 문의한다'가 각각 2.2%로 나타났다. 3. 연구대상자의 자가간호행위는 5점 만점에서 평균 3.93(0.42)점으로 나타났다. 가장 높은 자가간호행위 수행점수를 보인 영역은 약물복용 4.67점, 동정맥루 관리 4.29점이었고, 가장 낮은 영역은 사회생활 1.82점, 다음은 식이관리로 3.35점이었다. 4. 대상자의 일반적 특성에 따른 자가간호수행은 유의한 차이가 없었다. 5. 대상자의 질병관련 특성에 따른 자가간호수행은 정규적인 외래방문에서만 유의한 차이가 있었다(p=0.03). 6. 대상자의 증상대처 방법에 따른 자가간호수행은 유의한 차이가 없었고, 증상대처 방법에 대한 사전교육을 받은 대상자가 유의하게 자가간호수행이 높게 나타났다(P<0.01). 본 연구결과에 의하면 정규적으로 외래방문을 하고, 증상대처 방법에 대한 사전교육을 받은 혈액투석환자의 자가간호수행이 높았다. 그러므로 혈액투석환자들이 투석을 하는 시간동안 부족한 자가간호행위와 증상에 대한 대처방법을 구체적으로 교육함으로써 혈액투석환자들의 합병증 발생을 예방할 뿐만 아니라 자가관리를 향상시킬 수 있을 것으로 기대된다. [영문]The main purposes of this study were to identify and describe symptoms, home management methods of symptoms and self-care behaviors of the hemodialysis patients who visited the emergency department (ED). Patients on hemodialysis need lifelong treatment and have to adhere to careful self-care such as special diet, medication and regular visit to physician's office. However, some of these patients visit to ED with various symptoms related to improper self care. The subjects were 45 patients on hemodialysis who visited the emergency department at 2 Hospitals in Seoul from October 1, 2008 to November 30, 2008. A structured survey questionnaire and medical records were used for data collection and the data were analysed by using SAS 9.2 program. The results were as follows; 1. The chief complaints were dyspnea (22.2%) abdominal pain and discomfort (13.3%), dizziness, weakness, hypotension (11.1%), and atreriovenous fistula malfunction (11.1%). The final diagnosis were cardiac disease (24.4%), infection (24.4%), vascular disease (11.1%), neurologic disease (8.9%). Among those patients, 62.2% were hospitalized. 2. Pre-ED management of symptoms include 'observation of symptoms and bed rest' 15.6%, 'medication' 13.3%, 'visit to primary clinic' 8.9%, 'check blood sugar and blood pressure' 6.7%, 'check dressing and blood sugar' 2.2%, and 'call medical center for information' 2.2%, but 51.1% made visit to ED. 3. The mean score for self-care behavior was 3.93±0.42 (maximum 5.0). The self care activities scoring the highest was taking medications (4.67), followed by taking care of atreriovenous fistula (4.29). Engaing in social activities was lowest (1.82) and diet control was (3.35). 4. There were no significant differences between self-care behavior and general characteristics or illness characteristics of subjects. But the subjects made regular OPD visit showed higher scores in self-care behaviors (p=0.03). 5. The subjects who participated in education programs managed the symptoms better than the ones who did not participate in education program (P<0.01). According to the results of this study, patients who visited the OPD regularly and participated in the educational program managed their symptoms better and showed higher self care behavior. The most frequent symptoms presenting in this study was dyspnea which is often caused by pulmonary edema due to inappropriate diet. In conclusion, it is strongly recommended to provide routine and repeated education for these patients during the hemodialysis on proper self care by nurses. It usually takes 4-5 hours per dialysis and many patients visit the dialysis 2-3 times a week. By utilizing this time more efficiently, nurses can prevent most of these patients from visiting ED.ope

Sensitivity and uncertainty analysis of forest carbon stock changes in Korea

학위논문 (석사)-- 서울대학교 대학원 : 환경보건학과, 2011.2. 이승묵.Maste

Delayed cerebrospinal fluid rhinorrhea four years after gamma knife surgery for juvenile angiofibroma

Juvenile angiofibroma (JA) is a highly vascularized tumor that often recurs or regrows. Recently, gamma knife surgery (GKS) was attempted on unresectable or remnant JA. We experienced a JA case that developed cerebrospinal fluid (CSF) rhinorrhea 4 years after GKS. Two surgical excisions using midfacial degloving approach were performed before GKS. After radiosurgery, the tumor was controlled, and no early complications were observed. However, 4 years after, intractable CSF leakage developed as a late complication, and we thus performed 4 subsequent endoscopic surgical repairs. The CSF leakage is very rare but can occur as a late complication of GKS and should be treated aggressively.ope

단위 공변접다발의 평균 오일러 지표에 관하여

학위논문 (석사)-- 서울대학교 대학원 : 수리과학부, 2012. 8. Otto Van Koert.이 학위 논문에서 우리는 접촉과 사교 위상의 일부 정의와 몇 가지 정리를 상기한다. 모든 측지선이 주기적이고 일정한 길이를 갖는 다양체 M에 대하여, 단위 공변접다발 ST*M에 S¹-작용을 행한 상공간의 오일러 지표를 계산한다. 이로써 접촉 호몰로지론에 불변량인 평균 오일러 지표를 알아낸다. 또한, 이러한 특성을 갖는 다양체 중에서 subcritical fillable이 안되는 단위 공변접다발을 구한다.In this paper, we recall some definitions and theorems in contact and symplectic topology and compute the Euler characteristic of the quotient space of unit cotangent bundle ST*M by S¹-action where M has the property whose geodesics are all periodic with the same length. Hence, we check the mean Euler characteristic of ST*M, which is an invariant of contact homology theory, and distinguish which ST*M among those specific manifolds is not subcritical stein fillable.Abstract i 1 Introduction 1 2 Contact manifolds 2 3 Contact and Riemannian geometry 4 4 Circle actions on unit cotangent bundles 13 5 Homology of sphere bundles 14 6 Applications of the mean Euler characteristic 21 6.1 pplications 23 Abstract (in Korean) 25Maste

Improved outcomes after low-concentration hypochlorous acid nasal irrigation in pediatric chronic sinusitis.

OBJECTIVES/HYPOTHESIS: We aimed to evaluate the effectiveness of low-concentration hypochlorous acid (HOCl) nasal irrigation compared to isotonic normal saline for pediatric chronic rhinosinusitis. STUDY DESIGN: This was a randomized, prospective, active-controlled study. METHODS: This study investigated the effectiveness of 4 weeks of low-concentration hypochlorous irrigation by analyzing five categorized subjective symptoms and x-ray findings in pediatric patients with rhinosinusitis. Thirty-seven patients were enrolled, and 26 patients successfully completed the study. RESULTS: Total symptom scores significantly improved with both HOCl and normal saline nasal irrigation, but there was no difference between the two groups. X-ray scores also improved in both groups; improvement was much greater in the HOCl group than the placebo group. CONCLUSIONS: Nasal irrigation with HOCl is an effective adjuvant treatment compared to isotonic normal saline for pediatric sinusitis. LEVEL OF EVIDENCE: 1b.restrictio

Mitochondrial reactive oxygen species modulate innate immune response to influenza A virus in human nasal epithelium

The innate immune system of the nasal epithelium serves as a first line of defense against invading respiratory viruses including influenza A virus (IAV). Recently, it was verified that interferon (IFN)-related immune responses play a critical role in local antiviral innate immunity. Reactive oxygen species (ROS) generation by exogenous pathogens has also been demonstrated in respiratory epithelial cells and modulation of ROS has been reported to be important for respiratory virus-induced innate immune mechanisms. Passage-2 normal human nasal epithelial (NHNE) cells were inoculated with IAV (WS/33, H1N1) to assess the sources of IAV-induced ROS and the relationship between ROS and IFN-related innate immune responses. Both STAT1 and STAT2 phosphorylation and the mRNA levels of IFN-stimulated genes, including Mx1, 2,5-OAS1, IFIT1, and CXCL10, were induced after IAV infection up to three days post infection. Similarly, we observed that mitochondrial ROS generation increased maximally at 2 days after IAV infection. After suppression of mitochondrial ROS generation, IAV-induced phosphorylation of STAT and mRNA levels of IFN-stimulated genes were attenuated and actually, viral titers of IAV were significantly higher in cases with scavenging ROS. Our findings suggest that mitochondrial ROS might be responsible for controlling IAV infection and may be potential sources of ROS generation, which is required to initiate an innate immune response in NHNE cells.restrictio