An asymmetric dimeric structure of TrmJ tRNA methyltransferase from <i>Zymomonas mobilis</i> with a flexible C-terminal dimer

Gu, Do-Heon,Park, Mi-Young,Kim, Jeong-Sun Elsevier 2017 Biochemical and biophysical research communication Vol. No.

<P><B>Abstract</B></P> <P>The tRNA methyltransferase J (TrmJ) and D (TrmD) catalyze the transferring reaction of a methyl group to the tRNA anticodon loop. They commonly have the N-terminal domain (NTD) and the C-terminal domain (CTD). Whereas two monomeric CTDs symmetrically interact with a dimeric NTD in TrmD, a CTD dimer has exhibited an asymmetric interaction with the NTD dimer in the presence of a product. The elucidated apo-structure of the full-length TrmJ from <I>Zymomonas mobilis</I> ZM4 shows a dimeric CTD that asymmetrically interacts with the NTD dimer, thereby distributing non-symmetrical potential charge on the both side of the protein surface. Comparison with the product-bound structures reveals a local re-orientation of the two arginine-containing loop at the active site, which interacts with the product. Further, the CTD dimers have diverse orientations compared to the NTD dimers, suggesting their flexibility. These data indicate that an asymmetric interaction between the NTD dimer and the CTD dimer is a common structural feature among TrmJ proteins, regardless of the presence of a substrate or a product.</P>

Crystallization and preliminary structural study of the Thermobaculum terrenum Csh2 in the type IB CRISPR system

Do-Heon Gu,Suk-Youl Park,Jeong-Sun Kim 한국구조생물학회 2017 Biodesign Vol.5 No.3

CRISPR/Cas system is an RNA-mediated prokaryotic adaptive immune system against mobile genetic elements. Among three CRISPR/Cas systems, type I system has two functional units in removing nucleic acids, Cascade and Cas3. Type IB Cascade has been analyzed to have components of Csh1, Csh2, Cas4, and Cas5, whose structural and functional information is not available. To provide a structural background for the type IB Cascade, the preliminary structural study of the Csh2 from Thermobaculum terrenum is reported here. The purified recombinant protein was successfully crystallized using the precipitant solution composed of 10% (w/v) Polyethylene Glycol 3350, 2% (v/v) Tacsimate at pH 5.0, and 100 mM Sodium Citrate tribasic dihydrate at pH 5.6. Diffraction data were collected to a resolution of 1.93 Å using synchrotron radiation. The crystal belongs to the primitive triclinic P1 space group, with unit cell dimensions a = 31.04 Å, b = 54.65 Å, c = 96.46 Å, α = 73.6 º, β = 88.4 º and γ = 89.8 º. With two molecules in the asymmetric unit, the crystal volume per unit protein weight corresponds with 2.29 Å 3 ·Da -1 , resulting in 46% solvent.

마이크로 집속빔을 활용한 생체 고분자 구조 분석

구도헌(Do-Heon Gu),박석열(Suk-Youl Park),안형주(Hyungju Ahn) 한국고분자학회 2021 고분자 과학과 기술 Vol.32 No.4

Effect of chemical etching of fuel cladding surface on crud deposition behavior in simulated primary water of PWRs at 328 °C

Baek, Seung Heon,Shim, Hee-Sang,Kim, Jung Gu,Hur, Do Haeng Elsevier 2018 Annals of nuclear energy Vol.116 No.-

<P><B>Abstract</B></P> <P>The purpose of this work is to evaluate the effect of chemical etching of fuel cladding surface on crud deposition and sub-cooled nucleate boiling behavior in simulated primary water of a PWR at 328 °C (601 K) and 13.0 MPa. Crud deposition tests were conducted using an as-received cladding tube and a chemically etched cladding tube under sub-cooled nucleate flow boiling conditions. The boiling behaviors on the two different cladding tubes were also monitored through the acoustic emission technique during the crud deposition tests. The number of boiling events was much smaller on the chemically etched cladding tube than on the as-received cladding tube. The amount of deposit decreased by about 51% on the chemically etched cladding tube compared to that on the as-received cladding tube. The effect of chemically etched surface is discussed from the viewpoint of surface roughness, wettability, and the degree of sub-cooled nucleate boiling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of chemical etching of fuel cladding surface on crud deposition is presented. </LI> <LI> Boiling behavior on cladding tubes is monitored using acoustic emission technique. </LI> <LI> Boiling signals decreases significantly on the chemically etched cladding. </LI> <LI> The amount of crud deposits decreases on the chemically etched cladding. </LI> </UL> </P>

Visualization and acoustic emission monitoring of nucleate boiling on rough and smooth fuel cladding surfaces at atmospheric pressure

Baek, Seung Heon,Shim, Hee-Sang,Kim, Jung Gu,Hur, Do Haeng Elsevier 2018 Nuclear engineering and design Vol.330 No.-

<P><B>Abstract</B></P> <P>The purpose of this work is to evaluate nucleate boiling phenomena occurring on as-received rough and chemically etched smooth fuel claddings in water at atmospheric pressure using the visualization method and the acoustic emission technique. The onset of nucleate boiling on the smooth cladding surface occurred at higher temperature than on the rough cladding surface. The visible boiling phenomena remarkably decreased on the smooth cladding surface compared with those on the rough cladding surface. The density and energy of AE signals emitted from vapor bubbles on the smooth cladding surface decreased than those on the rough cladding tube. The variation trend of AE signals was in good agreement with the visualization results. Therefore, it is expected that the AE technique can be effectively utilized to monitor the boiling behaviors on the heated surfaces even under non-visualized conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nucleate boiling on a rough and smooth fuel cladding surface is observed visually. </LI> <LI> Nucleate boiling on the two different surfaces is monitored using acoustic emission. </LI> <LI> Nucleate boiling occurs more actively on a rough cladding surface. </LI> <LI> Acoustic emission data are in good agreement with the visualization results. </LI> </UL> </P>

Acoustic emission monitoring of water boiling on fuel cladding surface at 1bar and 130bar

Baek, Seung Heon,Wu, Kaige,Shim, Hee-Sang,Lee, Deok Hyun,Kim, Jung Gu,Hur, Do Haeng Elsevier 2017 MEASUREMENT -LONDON- Vol.109 No.-

<P><B>Abstract</B></P> <P>This paper aimed to observe the acoustic emission (AE) signals of water boiling occurring on fuel cladding surfaces under flow conditions at 325°C and 130bar. Visualization test was first performed to identify a correlation between the water boiling phenomenon and AE signals in a transparent glass cell at 1bar. Based on the correlations obtained at 1bar, the boiling AE signals were obtained at 325°C and 130bar and successfully analyzed through various AE parameters, such as frequency, energy and hit number. Relatively small bubbles were formed at 130bar, and the bubble density increased with the increase of the internal heater temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Acoustic signals emitted from water boiling at 1 bar and 130 bar are presented. </LI> <LI> Water boiling on fuel cladding surfaces is monitored using acoustic emission method. </LI> <LI> Acoustic emission data of water boiling is correlated with visualization test at 1 bar. </LI> <LI> Real boiling signals are extracted from the raw data mixed with the heater noises. </LI> <LI> The acoustic energy levels of bubbles at 130 bar are lower than those at 1 bar. </LI> </UL> </P>

Effects of heat flux on fuel crud deposition and sub-cooled nucleate boiling in simulated PWR primary water at 13 MPa

Baek, Seung Heon,Shim, Hee-Sang,Kim, Jung Gu,Hur, Do Haeng Elsevier 2019 Annals of nuclear energy Vol.133 No.-

<P><B>Abstract</B></P> <P>This work aimed to evaluate the effects of two different heat fluxes (20 W/cm<SUP>2</SUP> and 80 W/cm<SUP>2</SUP>) on fuel crud deposition behavior and sub-cooled nucleate boiling (SNB) behavior in simulated primary water of a pressurized water reactor at 13 MPa. The SNB behavior on the fuel cladding tubes was periodically monitored using an acoustic emission (AE) technique during the deposition tests. The number of boiling AE signals emitted on the fuel cladding tubes at 80 W/cm<SUP>2</SUP> was greater than that at 20 W/cm<SUP>2</SUP> throughout the deposition test. After the crud deposition tests, the amount of crud formed on the cladding tubes at 80 W/cm<SUP>2</SUP> increased by about 3.6-times compared with that at 20 W/cm<SUP>2</SUP>. In this paper, the effect of heat flux on fuel crud deposition is discussed from the viewpoint of the degree of SNB.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of heat flux on crud deposition and subcooled nucleate boiling are presented. </LI> <LI> Boiling behavior on cladding tubes is monitored using acoustic emission technique. </LI> <LI> The hit number of boiling acoustic signals at 80 W/cm<SUP>2</SUP> is larger than that at 20 W/cm<SUP>2</SUP>. </LI> <LI> The amount of crud deposition at 80 W/cm<SUP>2</SUP> is 3.6-times greater than that at 20 W/cm<SUP>2</SUP>. </LI> </UL> </P>

Poster Presentation : Preparation and Characterzation of Yttrium Oxide Based Coating Films by Spray Coating

( Chang Hoon Hwang ),( Ji Heon Yun ),( Hong Rim Lee ),( Jon Do Yun ),( Gu Hyun Lee ),( Jun Hyung Byun ) 경남대학교 신소재연구소 2013 신소재연구 Vol.25 No.-

Silicon carbide is excellent heat resistant and high oxidation resistant material at high temperature because of forming silicon oxide film on its surface. However silicon oxide film is degraded by active oxidation and vaporized to silicon monoxide at high temperature over 1800℃. Thus, protective film for silicon oxide film is required. In this study, yttrium oxide based coating film having high melting point was prepared to overcome this problem. Films were prepared by spray coating method. The microstructure and chemical composition were examined before and after the test with scanning electron microscopy and electron probe microanalysis.

젊은 대퇴골두 무혈성 괴사 환자에서 세라믹-세라믹 관절면을 이용한 인공고관절 전치환술

김신윤(Shin-Yoon Kim),김용구(Yong-Gu Kim),여준영(Jun-Young Yeo),김도헌(Do-Heon Kim),인주철(Joo-Chul Ihn) 대한정형외과학회 2004 대한정형외과학회지 Vol.39 No.3

목적: 50세 미만의 대퇴골 두 골 괴사증 환자에서 세라믹-세라믹 관절면을 이용한 무시멘트 고관절 전치환술에 대해 초기 임상적, 방사선학적 결과를 분석하고자 하였다. 대상 및 방법: 세라믹-세라믹 관절을 이용한 무시멘트 고관절 전치환술을 시행하여 최소 2년 이상 추시 가능하였던 59명, 68예를 대상으로 하였다. 대상 환자의 평균 연령은 39.4세(범위,16-49세)이었으며, 추시 관찰 기간은 평균 31.6개월(24-50개월)이었다. 수술 전 진단명은 모두 대퇴골 두 골 괴사증이었으며, 원인에 따라 특발성이 21예, 음주(alcohol)가 28예, 스테로이드가 11예, 후 외상성이 8예였다. 임상적으로는 Harris Hip Score (HHS)를 이용하여 평가하였고, 방사선학적 결과는 삽입물의 안정성과 골용해 발생을 관찰하였다. 결과: HHS는 수술 전 평균 61점에서 최종 추시 시95점으로 향상되었으며 우수가 57예(84%), 양호가 11예(16%)였다. 비구 측과 대퇴 측에서 컵의 이동이나 스템의 침강의 소견은 없었으며, 골용해 소견도 관찰되지 않았다. 합병증은 수술 후 탈구가 2예, 수술 중 근위 대퇴골 균열이 1예, 일과성 좌골 신경 마비가 1예 있었다. 결론: 50세 미만의 대퇴골 두 골괴사증 환자에서 세라믹-세라믹 관절면을 이용한 무시멘트 고관절 전치환술의 단기 추시 결과에서 임상적, 방사선학적으로 우수한 결과를 보였으나, 보다 장기적인 추시가 필요할 것으로 사료된다. Purpose: To evaluate the short-term clinical and radiographic results associated with use of the ceramic￢on-ceramic articulation uncemented total hip arthroplasty (THA) in patients less than fifty years old with osteonecrosis of femoral head. Materials and Methods: Sixty-eight THAs with use of the ceramic-on-ceramic articulation were performed in fifty-nine patients who were younger than fifty years old with the implantation of an uncemented plasma coated Plasma cup and Bicontact stem. All patients were available for complete clinical and radiographic analysis after a mean duration of a follow-up of 31.6 months (range; 24-50 months). The average age of the patients at the index operation was 39.4 years (range; 16-49 years). Preoperative diagnosis was osteonecrosis of femoral head in all hips. The causative factors were idiopathic in twenty-one hips; alcohol abuse in twenty-eight hips, steroid in eleven hips, and posttraumatic in eight hips. Clinical evaluation was done by Harris Hip score (HHS). Radiographic evaluation was done in terms of stability of components and prevalence of osteolysis. Results: The mean preoperative HHS of 61 points improved to 95 points at the time of the final follow-up. Excellent results were found in 57 hips (84%), good results were 11 hips (16%). No acetabular or femoral components were loosened radiographically. There was no evidence of osteolysis. There were two postoperative dislocation, one intraoperative femoral fissuring, and one transient sciatic nerve palsy. Conclusion: Short-term clinical and radiographic results associated with use of the ceramic-on-ceramic articulation un cemented THA in patients less than fifty years old with osteonecrosis of femoral head were excellent. However, longer-term follow up is needed.

Immortalization of Rabbit Corneal Fibroblasts by Overexpression of Simian Virus 40 Large T antigen

Cho, Seung-Ju,Park, Yuk-Pheel,Lim, Heon-Man,Kim, Jae-Chan,Yang, Eun-Kyung,Park, Jung-Keug,Yoon, Do-Young,Lee, Hee-Gu 대한의생명과학회 2004 Biomedical Science Letters Vol.10 No.2

Immortalization of primary corneal cells has influence on pharmacy, medical and biological fields. Especially, investigation of immortalization mechanism using viral oncoproteins is useful for medical treatments, and these cell lines will be useful materials for toxic test of medical supplies and cell biological experiments. Rabbit corneal fibroblasts in culture undergo a finite number of divisions before they reach a terminally non-proliferating state known as replicative senescence. Therefore, we attempted to induce immortalization of rabbit corneal fibroblasts with SV 40 large T antigen. As a result of experiment, expression of SV 40 large T antigen was confirmed, and expression of proteins related to cell cycle repressor was decreased in the transfection group compared with non-transfection group. According to the results of cell cycle phase distribution test, SV 40 large T antigen-transfected cells had obtained higher proliferation rate than primary cells. It was confirmed that during induction of immortalization, SV 40 large T antigen was not able to increase telomerase activity. In conclusion, we made a rabbit corneal fibroblast cell line with SV40 large T antigen. This cell line will be useful for further studies of mammalian fibroblast biology, particularly with regard to angiogenesis and malignant transformation. In addition, this cell line offers opportunity for testing potential therapeutics and can be used for toxicity tests of materials or cosmetics. In the future, our cell line can potentially be utilized in a wide range of biology related fields.