MC-50 싸이클로트론을 이용한 Mn-54 제법 연구

유국현,서용섭 東國大學校 2000 東國論叢 Vol.39 No.-

The half-life of ^54Mn is 312.2 days and main γ-energy is 835keV, therefore it is used as a standard source for a multi-channel analyzer and a dose calibrator and managanese catabolism study in human body. In this paper, a method for the production of no carrier added ^54Mn was studied via ^54Cr(p,n) and ^59Co(p, αpn), with MC-50 cyclotron and described chemical isolation method of ^54Mn from a irradiated target by ion exchange resin. Chromium and cobalt were used as target materials. The production yields of ^54Mn by 50.5 MeV protons was 4.5 μCi.μ/Ah on chromium target and 11.85 μCi/μAh on cobalt target. The cross-section and thick target yield of ^59Co(p, αpn)^54Mn reaction were measured in the energy range of 50.5→22.2MeV in order to determine the optimum conditions for the production of ^54Mn. the maximum cross-section was 47.48 mbarn at 41.2MeV.

^27Al(p,α pn)핵반응에 의한 무담체 ^22Na 제법 연구

유국현,서용섭,양승대 東國大學校 1998 東國論叢 Vol.37 No.-

A method for the production of no-carrier added(NCA) ^22Na was developed via ^27Al(p, ㄷαpn) nuclear reaction with 50.5MeV protons. the half life of ^22Na is 2.6 years and main γ-energy is 1274.5keV and it is used standard source and sodium catabolism study. The cross-section and thick target yield for the reaction was measured in detail in the energy range of 50.5→20.2MeV in order to determine the optimum conditions for the production of ^22Na. the maximum cross-section for the production of ^22Na was 40.8 mbarn at 43.85MeV. the calculated production yield of ^22Na by 50.5MeV protons on aluminium was 60.9μCi/μAh. The seperation of ^22Na was carried out by ion exchange, precipitation and diffusion. It was found that ion exchange column operation using AG50W-X4 resin was the most efficient method among them.

전류밀도 향상을 위한 금속 산화물 피막 제조에 관한 연구

채경선,유국현 동국대학교 자연과학연구원 2000 자연과학연구 논문집 Vol.5 No.-

구조물의 부식을 저감시키기 위한 재료로 사용되려면 전기 전도성이 좋아야 하며, 여러 산업환경에 적용될 수 있도록 내식성이 뛰어나야한다. 이리 듐-루테늄 산화물 피막은 이러한 성질을 만족시키는 물질로, 이들 산화물 피막 의 성질은 대개 양극 제조 공정에 의해 크게 좌우되므로 본 연구에서는 전류 밀도 향상을 위한 제조 공정을 최적화하고자 하였다. Dip-coating법으로 전도성 코팅층인 이리듐-루테늄 산화물 피막을 기지금속인 티타늄 위에 피복 시키는데, 이 코팅층의 내식성 향상을 위해서 다구치 방법을 도입하여 최적 공정 조건을 구하였다. 이때 사용된 변수는 전처리 방법, 열처리 온도, 열처리시 주입 가스량, 열처리 시간으로 이들 변수를 3가지로 변화시켜 실험하였다. 실험결과 이리듐-루테늄 산화물 피막 제조시 기판위에 티타늄산화물 중간층을 plasma spray법으로 제조하고, 열처리 온도 450℃, 주입가스량 3sccm, 열처리시간을 120분으로 하였을 때 방식전류밀도가 가장 우수한 코팅층(활성화 코팅층)을 얻었다.

Carboxymethyl-chitin 제조공정의 단순화

한상문,안병제,김용우,김용범,유국현,이승진 대한화학회 2001 대한화학회지 Vol.45 No.4

CM-chitin은 화장품 분야에서 보습제, 유연제, 피부관리를 위한 세포활성제 및 미백제등으로 다양하게 이용되고 있는 것으로 알려져 있다. 본 연구에서는 CM-chitin제조공정을 기존의 방법에서 몇가지 절차를 배재하여 단순화 하였다. Chitin분말을 NaOH와 혼합하고 16hrs 동안 동결 및 교반을 통해 CICH_(2)COONa와 isopropyl alcohol혼합액을 첨가하였다. 그 결과 높은 치환도의 CM-chitin을 얻을 수 있었다. The water soluble carboxymethyl-chitin(CM-chitin) has been well known to be very useful to the cosmetic field as a moisturizer, a smoothener, a cell activater and a cleaner for face skin conditioning. In this study, the preparation process of CM-chitin was simplified with elimination of some procedures in the conventional method. The chitin powder was mixed with sodium hydroxide solution. And then a mixture of sodium monochloroacetate(or monochloroacetic acid) and isopropyl alcohol(or a mixed solution with water and isopropyl alcohol) was added to thorough the agitation and the freezing during 16 hours. The CM-chitin with a high degree of substitution by the improved process was obtained.

On-line Methionine 합성장치 개발에 관한 연구

Yu,Kook-Hyun,Choi,Kang-Hyuk 동국대학교 자연과학 연구원 1999 자연과학연구 논문집 Vol.4 No.-

[11C]-Methionine has been used for the tracer as an evaluation of amino acid metabolism and protein synthesis rate in tumor imaging. Radio isotope, 11C, has 20 minutes half life and its radioactivity need an on-line system used for protecting researcher against the radiation. We have developed two on-line system for methionine synthesis. one is a solid supported system, the other is a liquid phase system. In comparative cold experiments, Methyltriflate provided higher productivity(90%) in solid supported system than productivity(32%) in liquid phase system. we could obtain methionine from the on-line synthesized methyltriflate.

Synthesis of [¹⁸F]Fluorocholine Analogues as a Potential Imaging Agent for PET Studies

Yu, Kook-Hyun,Park, Jeong-Hoon,Yang, Seung-Dae Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.4

There have been intensive studies concerning $[^{11}F]$choline ($[^{11}F]$methyldimethyl( ${\beta}$ -hydroxyethyl) ammonium) (1) which is known as a very effective tracer in imaging various human tumors localized in brain, lung, esophagus, rectum, prostate and urinary bladder using Positron Emission Tomography (PET) and there is increasing interest in $^{18}F$ labelled choline (2) and proved to be useful to visualize prostate cancer. We have prepared six $^{18}F$ labelled alkyl choline derivatives (3a-3c, 4a-4c) from ditosylated and dibrominated alkanes in moderate yields. The six alkyl tosylate or bromate ammonium salts have been synthesized as precursors. Radiofluorination was achieved by the treatment of precursors with $^{18}F$ - in the presence of Kryptofix-2.2.2.. The labeling yields varied ranging from 7 to 25%.

Synthesis of Carrier Free [32P] 5-Chloro-8-Quinolyl Phosphate as a Phosphorylating Agent

Kook-Hyun Yu,Ul-Jae Park,Hyon-Soo Han,Kang-Hyuk Choi 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.7

Expressional Regulation of Replication Factor C in Adipocyte Differentiation

Hyun Kook Cho(조현국),Hye Young Kim(김혜영),Hyun Jeong Yu(유현정),JaeHun Cheong(정재훈) 한국생명과학회 2011 생명과학회지 Vol.21 No.2

지방세포 분화 과정 중에 key regulator로서 기능을 하는 여러 전사조절인자(PPARγ, C/EBPα, SREBP, LXR)가 동정되었고, 주로 DNA 복제나 DNA 수선 단계에서 중요한 역할을 한다고 밝혀진 복제 조절인자인 RFC140이 지방세포 분화에도 중요한 인자임이 밝혀졌다. 이 연구에서 우리는 RFC140과 RFC38에 대한 발현조절을 확인하였으며, RFC140이 PPARγ와의 단백질-단백질 결합을 통하여 PPARγ에 의해 조절되는 유전자의 발현을 증가시킴을 확인하였다. 이러한 결과들은 특이적인 지방세포 전사인자에 의해 발현이 조절되는 RFC140과 RFC38이 지방세포의 분화과정에 필수적임을 제시한다. Adipocyte differentiation is an ordered multistep process requiring the sequential activation of several groups of adipogenic transcription factors, including CCAAT/enhancer-binding protein-α and peroxisome proliferator-activated receptor-γ, and coactivators. In previous reports, we identified that replication factor C 140 (RFC140) protein played a critical role in regulating adipocyte differentiation as a coactivator. Here, we show expressional regulation of RFC140 and small RFC subunit, RFC38, following characterization of gene promoter of RFC140 and RFC38. In addition, RFC140 increases PPARγ -mediated gene activation, resulting from direct protein-protein interaction of RFC140 and PPARγ. Taken together, these findings demonstrate that the regulated expression of RFC140 and RFC38 by specific adipocyte transcription factors is required for the adipocyte differentiation process.

Poster Session:PS 1182 ; Cardiology : The Clinical Characterization and Preoperative Coronary Angiography of Cardiac Myxoma

( Tae Hyun Kim ),( Sang Hyun Lee ),( Yu Hee Choi ),( Soo Yong Lee ),( Jong Min Hwang ),( Min Ku Chon ),( Ki Won Hwang ),( Jeong Su Kim ),( Yong Hyun Park ),( June Hong Kim ),( Kook Jin Chun ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: The aim of our study was to investigate clinical features as well as coronary angiographic fi ndings in patients with cardiac myxoma. Methods: We performed a retrospective review of the 25 patients with cardiac myxoma, who had received surgical resection from July 2008 to June 2014 at our hospital, recording age, sex, symptoms, tumor location, echocardiography fi ndings and coronary angiography for each patient. Results: In 25 patients there were 9 (36%) men and 16 (64%) women with median age 55; range 17-69 years. The clinical features of 25 patients were showed in fi gure 1. fifteen (60%) patients underwent preoperative selective coronary angiography. All coronary angiographies showed that there were no signifi cant stenoses of coronary arteries. Thirteen (87%) cases of total 15 coronary angiographies showed ‘tumor vascularity’ looks like aterio-cavitary fi stula and feeding vessels. In the thirteen patients, eight (62%) patients had feeding arteries of myxoma from right coronary artery (RCA), three (23%) patients had feeding vessels from left circumfi ex coronary artery (LCx) and two (15%) patients had dual feeding arteries from RCA and LCx. There was no feeding artery from left anterior descending coronary artery (LAD). Conclusions: Our data demonstrated that the almost coronary angiograms (87%) to exclude concomitant coronary artery disease before surgery showed feeding vessels and tumor vascularity of cardiac myxoma from RCA or LCx. We showed that feeding arteries of cardiac myxoma from RCA were found more frequent than from LCx. Also, there was no feeding artery from LAD.

양전자단층촬영에 이용 가능한 새로운 심근 혈류 추적자 개발 ; F-18이 표지된 유기암모늄의 합성과 체내분포에 관한 연구

유국현 ( Kook Hyun Yu ) 대한핵의학회 1994 핵의학 분자영상 Vol.28 No.3

In order to develop a F labelled myocardial perfusion agent(flow tracer) for PET, F- labelled organic ammonium cations were synthesized and evaluated in relation to their biodistri.bution. Five quaternary organic ammonium compounds were iabelled with F in a side chain with moderate to good yields by direct introduction of F fluoride. Radiochemical yields have been achieved in 30 40min by the precursors(tosylates) in dimethylsulfoxide 15 60% (decay corrected). The reaction was found to be autocatalyzed. A remote controlle proeedure was developed in these synthesis. 99mF Labelling and HPLC purification of compounds needed about 60 min(Yield: 7 20% ). Up to now the two compounds N 4 [15F]fluorobutyl pyridinium cation(1) and N, N dibenzyl 4(2 [15F]fluoroethyl)piperidinium cation(2) were investigated in relation to their biodis(ribution in mice. Compound 1 showed at 1 min post injection the high upt.ake of 19,22% ID/g organ in the myocardium but a following fast decline to 1.12% ID/g organ after 40min. Uptake of compound 2 was after 1min in the heart 5.90% ID/g organ but after 40min at the relative high value of 4.33% ID/g organ. Heart:blood ratio for compound(1) at 1 min was 8.3, at 40 min 2.6 for compound II 2.0(lmin> and 15,0(40 min). As data of compound 2 showed greater heart uptake, slower myocardial release, and higher heart:blood ratios, compound 2 is a good candidate for further evaluation.