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Evaluation between 3.0 T vs 1.5 T MRI in Detection of Brain Metastasis using Double Dose Gd-DTPA
정우석,정태섭,김형중,안철민,이재훈,허진,조응혁 대한자기공명의과학회 2005 Investigative Magnetic Resonance Imaging Vol.9 No.2
목적: 작은 뇌전이 종양의 조기 발견은 중요하다. 이 연구의 목적은 1.5 T MRI와 3.0 T MRI 간의 크기에 따른 뇌전이 종양의 발견율을 비교하는 것이다. 대상 및 방법: 폐암으로 진단 받은 162명의 환자를 대상으로 TNM 병기를 위해 뇌 MRI를 시행하였다. Gd-DTPA를 2배 용량으로 투여 후, 3.0 T MRI에서 훼손경사회복획득으로 촬영하였으며 그 후 1.5 T MRI에서 T1 스핀 에코로 촬영하였다. 3명의 방사선과 전문의가 합의하여 MRI를 판독하였으며 정성 평가를 시행하였다. 3.0 T와 1.5 T MRI에서 크기에 따라 민감도, 양성 예측률, 정확도를 평가하였다. 신호 강도를 사용하여 전이 종양과 인접 조직간의 신호강도 비를 계산하였다. 결과: 162명의 환자 중 31명에서 1.5 T 또는 3.0 T MR에 뇌전이 종양이 발견되었다. 3.0 T MRI에서 143개의 종양이 발견되었으나 1.5 T MRI에서 137개의 종양이 발견되었다. 6개의 종양이 3.0 T MRI에서만 발견되었으며 크기는 모두 3 mm 미만이었다. 3.0 T MRI의 민감도, 양성 예측률, 정확도는 각각 100%, 100%, 100%이며, 1.5 T MRI에서는 각각 95.8%, 88.3%, 85.1% 이다. SI ratio는 1.5 T MRI보다 3.0 T MRI에서 유의하게 높았다 (p=0.025). 결론: Double dose Gd-DTPA를 이용한 3.0 T MRI는 3 mm미만의 뇌전이 종양을 발견하는데 있어서 1.5 T MRI 보다 우수하다.
정우석,김성섭,서상택 한국농촌지도학회 2018 농촌지도와 개발 Vol.25 No.1
This study analyzed the selection factors for cultivation practices in paddy rice farming. For the study, conjoint model with part-worth utility was adopted, where model profiles included three attributes of yield, production cost, and cultivation difficulties and two levels for each attribute. The value of each level w as set up with experimental data obtained from National Institute of Crop Science. Ninety three rice farmers, who joined Korea Rural Economic Institute as farm er correspondences, were surveyed through internet with the profiles selected by factorial design. Result showed that rice farmers considered cultivation difficulties as the most important selection factor to adopt new cultivation practices followed by production cost and yield in consecutive order. This results were robust in spite of past experiences with new practices, willingness to adopt new practices in the future, imitative nature and government interventions.
정우석,박철,권세진 한국항공우주학회 2014 한국항공우주학회 학술발표회 논문집 Vol.2014 No.11
5단 로켓을 이용한 우주의 처분된 핵 폐기물에 대한 관리 방법을 연구하였다. L4, L5 지점에 위치한 핵폐기물은 전자기력을 이용하여 하나의 덩어리로 묶어서 관리할 수 있으며 그러한 시스템의 개념을 제시하였다. 유사시 소행성의 충돌 위험이 있을 경우, KSLV-2의 기술을 기반으로 한 5단 로켓을 통해 핵폐기물을 이동시킬 수 있다. 그리고 이 5단 로켓은 3.5 Phase method를 통해 원하는 지점까지 도달할 수 있음을 확인하였다. Dump site management of nuclear waste using 5<SUP>th</SUP> stage rocket was studied. Nuclear waste is managed as a group by electromagnetic force. In an emergency of an imminent asteroid collisi on, the 5<SUP>th</SUP> stage rocket vehicle, of a KSLV-2, can move the group of nuclear waste away fro m the danger. This rocket can move to the L4 or L5 using a 3.5 phase method. The 5<SUP>th</SUP> stage rocket with a payload of 400kg can be used for this purpose.
Combinatorial Approach to the Fabrication of Zinc-Tin-Oxide Transparent Thin-Film Transistors
정우석,윤성민,Jae-Heon Shin,황치선 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1
Zn-Sn-O (ZTO) thin films were prepared for channels in top-gate transparent thin-film transistors (TTFTs). Thin ZTO films (∼20 nm) with a wide range of compositions could be easily formed by using a combinatorial method with two RF magnetron sputter guns equipped with ZnO and SnO<SUB>2</SUB> targets. Specially, ZTO-TTFTs could be fabricated by using low thermal processes at temperatures below 300 ℃, where electrical properties were improved by controlling both the deposition rate and the temperature. In ZTO films with a compositional zone from [Zn : Sn = ∼4 : 1] to [Zn : Sn = ∼2 : 1] and amorphous-like structures, reliable transfer plots with high Ion/Ioff ratios (>10<SUP>7</SUP>) could be obtained.
제2형 당뇨병환자에서 혈중 글루카곤 농도와 심혈관 질환 위험도의 관계
정우석,문재철,유소연,Jeong, Wooseok,Moon, Jaecheol,Yoo, Soyeon 제주대학교 의과학연구소 2020 The Journal of Medicine and Life Science Vol.17 No.2
Glucagon regulates glucose and fat metabolism as well as being involved in the production of ketone bodies. The new antidiabetic drug, a sodium-glucose co-transporter-2 inhibitor, increases glucagon, and reduces the risk of cardiovascular death and hospitalization due to heart failure. The presence of metabolic syndrome is an important risk factor for cardiovascular diseases(CVD) in type 2 diabetes(T2DM) patients. We, thus, investigated the association between glucagon levels and metabolic syndrome in T2DM patients. This cross-sectional study involved 317 T2DM patients. Fasting and postprandial (30 min after ingestion of a standard mixed meal) glucagon levels were measured. Metabolic syndrome was defined according to the criteria of the International Diabetes Federation. A multiple regression logistic analysis was employed for statistical evaluation. A total of 219 (69%) subjects had metabolic syndrome. The fasting and postprandial glucagon levels did not differ between the group with metabolic syndrome and the group without. Postprandial glucagon levels increased significantly with the increase in the number of metabolic syndrome components, but the fasting levels did not. However, a hierarchical logistic regression analysis revealed that the postprandial glucagon levels did not contribute significantly to metabolic syndrome even after adjusting for other covariates. Fasting and postprandial glucagon levels are not associated with metabolic syndrome in T2DM patients. However, further studies are needed to investigate the relationship between glucagon and cardiovascular risk in patients with T2DM.