Magnetic Resonance Imaging: Historical Overview, Technical Developments, and Clinical Applications

Jahng, Geon-Ho,Park, Soonchan,Ryu, Chang-Woo,Cho, Zang-Hee Korean Society of Medical Physics 2020 의학물리 Vol.31 No.3

The authors congratulate the cerebrations for the 30 years of the Korean Society of Medical Physics (http://www.ksmp.or.kr/). The paper is published to recognize the anniversary. Geon-Ho Jahng invited Professor Z. H. Cho to join to submit this manuscript because he has been one of the leaders in the field of magnetic resonance imaging (MRI) during the last 40 years. In this review, we describe the development and clinical histories of MRI internationally and domestically. We also discuss diffusion and perfusion MRI, molecular imaging using MRI and MR spectroscopy (MRS), and the hybrid systems, such as positron emission tomography-MRI (PET-MRI), MR-guided focused ultrasound surgery (MRgFUS), and MRI-guided linear accelerators (MRI-LINACs). In each part, we discuss the historical evolution of the developments, technical developments, and clinical applications.

심한 하악골 전돌증 환자의 외과적 치험례

권대근,이상한,이근호,장도근 大韓顎顔面成形再建外科學會 1994 Maxillofacial Plastic Reconstructive Surgery Vol.16 No.1

Obwegeser Ⅱ method and Rigid fixation conserving the condylar position has been performed on 5 patients with severe mandibular prognathism, and we obtained the result after the follow up study follows. 1. Obwegeser Ⅱ method is considered to move the distal segment passively when surgical correction of severe open bite correction and large amount of set back above 15mm is needed. 2. In one case that has more change of condylar position after operation, documented immediate post- operative relapse have been occurred 3. In the others that have adequate control of condylar position, passive set back and firm skeletal fixation, more functional and esthetic improvement and more post-operative stability has been achieved

The Antioxidant Effect of the Rhaponticum uniflorum Extracts on the Oxidative Stress in H₂O₂ induced Human Keratinocytes

So Hee Ahn,Won Yeoung Choi,Ji Won Jeong,Geon Woo Park,Su Yeon Kang,Eun Jeong Kim,Su Rim Sin,Eun Seo Jang,Gye Won Lee,Young Ho Cho 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10

In this study, To investigate the antioxidant activities of Rhaponticum uniflorum extracts (RUE), we assessed scavenging activities on DPPH, ABTS radicals, and reducing power. The DPPH and ABTS radical scavenging activities (SC50) of RUE were 96.97±1.19 μg/mL and 31.26±0.13 μ g/mL, respectively, and the reducing power significantly increased dose-dependent manner. To study the antioxidant effecters of RUE in H₂O₂ induced human keratinocytes, expression of Nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined by Western blot and qRT-PCR. RUE induced the expression of HO-1, a critical target enzyme of Nrf2, in a concentration-dependent manner. The expression of HO- 1 mRNA was also induced in H₂O₂-treated HaCaT cells but no significant difference in the level of HO-1 mRNA was observed. Taken together, these results suggest that RUE may be useful as a potential ingredient for anti-aging products.

정신지체의 대체의학적 치료접근

반건호 경희대학교 2001 慶熙醫學 Vol.17 No.1

항암제 투여가 이식된 가토 유리자가골의 치유에 미치는 영향

이근호,장현중 慶北大學校 齒科大學 1993 慶北齒大論文集 Vol.10 No.2

저자는 가토 16마리를 사용하여 하악골편을 절제하여 재이식한 후 7일째 대조군 8마리에 생리식염수 5cc를 정주하고 실험군 8마리에 체중 1kg당 Cisplatin 2mg과 5-Fluo- ruracil 40mg을 정주한 후에서 각각 3, 7, 14, 21일째 군별로 2마리씩 희생시켜 이식골의 치유과정을 조직학적으로 비교 관찰하여 다음과 같은 결과를 얻었다. 1. 투약후 3일(이식후 10일)째 이식된 골조직내의 세포는 생활력을 나타내며 골간극에는 신생골주가 형성되었다. 2. 투약후 7일째 형성된 골소주에 의해 수용체와 이식골이 유합되기 시작하여 투약후 14일째 대부분에서 골성유합이 완성되었어며 투약후 21일째에는 재형성과정이 진행되었다. 3. 투약후 각 기간별로 대조군과 실험군에서 명확한 차이는 없었다. The purpose of this study is to investigate the effect of antineoplastic agents on the healing process of free autogenous bone graft to reconstruct mandible immediately after tumor resection. Sixteen rabbits, resected and replanted a part of mandible, were divided into two groups. The eigth experimental rabbits were administrated cisplatin 2mg and 5-fluorouracil 40mg per kg of body weight, and the eight controls were administrated normal saline 5cc on postoperation 7 days. Each of them was sacrified 3,7,14 and 21 days after administration of drugs. Specimens were obtained and processed in a routine manner for H-E stain. After light microscopic examination, following results were obtained. 1. In 3 days after administration of chemotherapic agents, the cell in the graft showed vitality, and new trabecular bone was formed in the gap between host and graft bone. 2. In 7 days after administration, bony union between host bed and graft by new-formed trabecular bone was appeared, and in 14 days achieved almost. In 21 days, remodeling process was appeared. 3. There was no significant difference between experimental and control groups.

定期船 海運의 運賃決定要因과 安定化方案에 관한 硏究

박호건,안기명 한국해운물류학회 2002 해운물류:이론과실천 Vol.- No.3

정기선 해상운송과 관련 운임 결정에 있어서 경제 이론적, 경영 과학적 접근방법과 카르텔 형태인 해운동맹 등을 통하여 인위적이고 물리적인 방법 하에 적정운임 결정을 도출하려는 연구가 이루어져 왔으나 현대조선 기술의 발달과 단위당 비용 절감을 통해 규모의 경제를 실현하고져 계속되는 초대형 컨테이너 선박의 건조는 제한된 정기선 시장에 만성적인 선복 공급 과잉이 되어 극심한 경쟁으로 기존 운임시장이 교란되어 원가이하의 운임 수입으로 해운기업들의 통폐합 또는 존폐문제로 귀결되고 있으며, 더욱이 정기선 시장의 불안정과 운임의 극심한 편차는 궁극적으로 안정된 국제 상품 교역에 위해 요소로 작용하고 있는바 이와 관련 정기선 시장의 운임에 영향을 미치는 요인을 실증 분석하여 그 대책과 방안을 제시하여 정기선 시장의 질서 유지와 운임 안정화를 도모하는데 연구목적을 두고져한다. The global liner shipping markets have changed significantly since year 1990 especially in containerized liner freights. The number of liner containers has increased steadily to about 6-12 percent every year and KMI forecasted global container movements in year 2002 as 248 million TEU showing 142% up on 103 million TEU in year 1992. As well, the number of container vessels and its loading capacity have increased drastically for the purpose of contributing to the increase in worldwide demand for liner freights and the existence of economies of vessel size. KMI reported that the global loading capacity of container fleets will be estimated as 5.5 million TEU showing 150% up on 2.2 million TEU in year 1992 and the size of vessel to be ordered by global carriers become bigger and larger to Post/Super panamax model of 6,000-8,000 TEU capacity as fifth to seventh generation type. Ultimately, the trend to more and larger ships has been accompanied by strong growth in available liner capacity. Most of trade routes have been oversupplied with ship slots and reported that the surplus ratio of ship's slots will be around 24.5% in year 2002 and further estimated excess capacity of 30-40% in the Trans- pacific and the Europe trade. Eventually, such excess capacity in liner shipping is a result of increased competition among the carriers, in which appears to have led to a quest for lower freight rates and lower costs. In turn the liner market has been extremely unstabilized by intense and unfair competition each other and the profitability of liner carries become poor and lower and such low profits may be a force driving toward strategies involving alliances, mergers and building bigger ships in an effort to capture economics of scale and scope. To make it worse, some of carriers having financial difficulties have finally gone to the bankruptcy. Accordingly, the primary objective of this thesis is to explain the determinant of the freight rates theoretically and practically and to find out how to take an appropriate measures to be stabilized for liner markets and liner freight rates through the introduction of institutional and systematical approaches to the liner shipping industry.

절연 파괴 특성을 이용한 에폭시 복합체의 절연 신뢰도 예측

박건호,이준웅 광운대학교 신기술연구소 1996 신기술연구소논문집 Vol.25 No.-

본 연구에서는 송배전 계통에서 변성기의 몰드 재료로서 널리 사용되고 있는 에폭시 수지를 시료로 하여 설정해 높은 배합비에 따라 5종으로 제작한 각 시편에 대해 절연 파괴 실험을 하였다. 절연파괴 데이터를 가지고 와이블 분포식을 이용하여 임의의 허용 파괴 확률에서의 허용인가 전계의 값을 추정하였으며 절연 안전성을 판단하기 위하여 경년 열화(經年劣化) 데이터의 통계 처리를 행한 결과 허용 파괴 확률을 0.1[%]로 하였을 때, 허용 인가 전계는 21.5[kV/mm] 이하가 되어야 함을 확인할 수 있었다. In this study, the dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. The more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical, and the breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. From the analysis of Weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5[kV/mm].

지수분포를 따르는 가속수명자료의 적률추정법에 기초한 경험적 베이즈 예측분석

조건호,이우동,하일도 慶山大學校 基礎科學硏究所 1997 基礎科學 Vol.1 No.2

본 논문은 지수수명분포에서 제2종 중도절단된 가속수명자료를 이용하여 고장률의 사전분포의 평균을 알 때, 정상조건하에서 하나의 미래 관찰치의 예측문제를 사전분포의 모수에 대하여 적률추정량에 기초한 불편추정량(unbaised estimator)을 이용하는 경험적 베이즈 접근방법을 적용시켜 경험적 베이즈 예측분포와 예측구간에 대하여 연구하였다. In accelerated life tests(ALTs), the failure time of a test item is observed under high stress conditions, and based on these data, one intrests statistical inference on the parameters of lifetime distribution at the normal stress. Under the type-II censoring, we assume that the life distribution is exponential distribution. When the information on the prior is partially known, we device the empirical Bayesian analysis of ALTs data in order to obtain the empirical Bayesian predictive density and predictive intervals for a future observation under the normal stress level.

유소아의 반복행동. 습관인가 정신병리인가?

반건호,김태 경희대학교 2002 慶熙醫學 Vol.18 No.3-4

급성 심근 경색증과 혈장 Paraoxonase activity와의 관계

김건영,윤상준,박근호,조영신,장성종,장경식,홍순표 조선대학교 부설 의학연구소 2000 The Medical Journal of Chosun University Vol.25 No.1

연구배경: 혈장 파라옥소나제의 감소는 HDL-cholesterol의 항 산화작용의 중요한 요소로 알려져 있어 이의 감소는 항산화작용의 저하로 인해 동맥경화의 진행을 촉진시킬 수 있어 허혈성심장병의 주요 위험인자로 추정하고 있다. 본 연구에서는 급성 심근 경색증 환자를 대상으로 혈장 파라옥소나제의 활성도를 측정하여 정상군과 비교하여 혈장 파라옥소나제 활성도의 감소가 급성 심근 경색증의 위험인자인지 알아보고자 하였다. 대상 및 방법: 급성 심근 경색증으로 입원한 39 명의 환자(남자 : 여자 = 19 : 20, 평균나이: 61±4.3세)와 정상 대조군 36명(남자 : 여자 = 17 : 19, 평균나이: 55±10세)을 대상으로 정맥혈을 채혈 후 파라옥소나제 활성도와 LDL-cholesterol, total cholesterol, HDL-cholesterol를 측정하였다. 두 군간의 비교는 Student T-test를 이용하였다. 결과: 건강 대조군과 급성 심근 경색 환자군 간에 측정치를 비교해본 결과 혈장 콜레스테롤 수치는 182.10± 12mg/dl, 194.87± 40mg/dl이고 HDL 콜레스테롤은 54±5.4mg/dl, 37.52± 13mg/dl 였다. LDL 콜레스테롤은 94.45±13mg/d1, 122±34mg/d1로 급성 심근 경색증 환자의 경우 통계학적으로 의미있는 차이를 보였다. (P<0.05). 그러나 혈장 파라옥소나제 활성도는 건강 대조군 112.35±15U/ml, 급성심근 경색증 환자군 96.10±43.50U/ml로 급성 심근 경색증 환자군이 건강 대조군에 비해 낮은 수치를 보이는 경향이 있었으나 통계학적으로 유의한 차이(P=0.071)는 보이지 않았다(Table 2참조). Background : Human plasma paraoxonase is a HDL-associated ester hydrolase that catalyzes the hydrolysis of organophosphates, aromatic carboxylic acid esters and carbamates. HDL has been implicated in the prevention of LDL lipid peroxidation. Low paraoxonase activity in the Plasma may have responsibility to the development of coronary artery disease partially because oxidized LDL has intimate relationship with atherosclerosis. We studied plasma paraoxonase activities in the plasma of acute myocardial infarction patients in order to evaluate the relationship between these enzyme activities and the acute myocardial infarction. Materials and Methods : plasma samples were obtained from 39 individuals with acute myocardial infarction(M: 19 cases, F: 20cases, mean age: 61(4.3 years) and 36 individuals of healthy control(M: 17 cases, F: 19cases, mean age: 55(10 years). We determined paraoxonase activities, total cholesterol, LDL-cholesterol &DL-cholesterol levels in the plasma samples. Paraoxonase activities were measured spectrophoto metrically in 0.1M Tris-HCl buffer (pH=7.4) at 25℃ with paraoxon as substrate(5.5mM) at 405 nm. We used student T-test to compare the results of both groups. Results : Comparison of the results between myocardial infarction patients and normal control groups revealed that plasma total cholesterol, HDL-cholesterol and LDL-cholesterol levels showed statistically significant differences between groups but plasma paraoxonase activity does not. Conclusion : Our study showed that there was no significant difference of plasma paraoxonase activity between acute myocardial infarction and normal population. So low plasma paraoxonase activity may not be a risk factor of acute myocardial infarction. but further prospective large scale study will be needed to conclude.