Correlation between the DNA methyltransferase (Dnmt) gene family and genome-wide 5-methylcytosine (5mC) in rotifer, copepod, and fish

이재성,이재성,김보미,Leda Mirbahai,Angela Mally,J. Kevin Chipman 한국유전학회 2016 Genes & Genomics Vol.38 No.1

DNA methyltransferases (DNMTs) are an enzyme family that catalyzes the transfer of a methyl group to DNA for a wide variety of biological functions. To determine whether the number and composition of the Dnmt gene family affects the 5-methylcytosine (5mc) ratio at the genome level, genome-wide 5mc ratios from three marine animals, the mangrove killifish (Kryptolebias marmoratus), an intertidal copepod (Tigriopus japonicus), and a monogonont rotifer (Brachionus koreanus), were analyzed in each organism after the cloning of Dnmt genes. Lineage- and teleost-specific gene evolution was observed in the vertebrate Dnmt3 gene family, while unique gene expansion was found in the T. japonicus Dnmt1 gene family. However, the rotifer did not have any apparent homologue of Dnmt1 or Dnmt3 in its genome. This gene information was highly supportive of genome-wide 5mc levels in the three marine animals. Therefore, the absence or presence of the Dnmt gene family could be an important evolutionary parameter of how this could affect genomewide epigenetic metabolism.

미량의 코발트 첨가가 W-Cu 전기 접점재의 성질에 미치는 영향

이재성,문인형 대한금속재료학회(대한금속학회) 1977 대한금속·재료학회지 Vol.15 No.2

高負荷能을 갖는 W-Cu系 전기 접점재의 미량의 Co를 첨가함으로서 얻어지는 諸使用特性의 變化를 單純W-Cu系와 또 미량의 Ni을 첨가한 경우와 對比 조사하였다. W-Cu-Co (tr.)系는 W-Cu-Ni (tr.)系나 W-Cu系에 比하여 旣發表한 바와 같은^(1)) 燒結 및 溶侵時에 보여주는 有利한 製造上의 特性이외에도 그 전기적특성에 있어서도 뚜렷한 개선을 보여주었다. W-Cu-Co(tr.) 系는 同一한 使用條件아래에서 W-Cu나 W-Cu-Ni (tr.)系에 比하여서 보다 낮은 接觸抵抗과 contact erosion 율을 보였다. 이와 같은 낮은 contact resistance나 contact erosion 현상은 W-Cu-Co 系에서도 W-Ag-Co에서와 같이^(2,3)) Co_7W_6 金屬間化合物이 W粒子주변에 형성되어 접점저항의 증가를 가져오는 복잡 산화물의 형성을 저지하기 때문이라 생각된다. ※^(1)) 李載星, 文仁炯 : 大韓金屬學會, 1976年度秋季學術發表會서 "미량의 코발트 첨가가 W-Cu 전기 접점재의 수축거동에 미치는 영향"발표(同學會誌 14권 4호의 초록 발표) ※^(2)) Kabryamc, et al: PMI 5 (1973) 122 (3) I.H. Moon and W.J. Huppmann: PMI 6 (1974) 190.

Identification and analysis of whole microcystin synthetase genes from two Korean strains of the cyanobacterium Microcystis aeruginosa

이재성,한스-우베 담스,최범순,이재성,최익영 한국유전학회 2012 Genes & Genomics Vol.34 No.4

Microcystins are cyanobacterial hepatotoxins, and are produced by nonribosomal enzyme complexes, mcy gene cluster. In this study, we report on whole mcy gene clusters from two Korean strains of M. aeruginosa that were blooming in Lake Paldang (FCY-26) and Geum river (FCY-28). Their specific gene locus, amino acid information, and sub-cluster orientation were also characterized in both strains. Both gene clusters are of 55 kb, and also each length, number and the arrangement are identical. Their sequence analysis revealed a cluster of 10genes (mcyA, B, C, D, E, F, G, H, I, and J) involved in the biosynthesis of microcystin, and mcyABC and mcyDEFGHIJ formed two polycistronic operon structures that are transcribed bidirectionally from a central promoter region between mcyA and mcyD. The analysis of SNPs provided different nucleotide composition and amino acid variations in two Korean strains of M. aeruginosa. This approach is useful to develop genetic indicators identifying toxic cyanobacteria and their cyanotoxins,and helpful for a better understanding of the diversities of mcy gene clusters, the biosynthesis of microcystin, and the mediation of environmental parameters causing algal blooming and HABs.

Multi Stage Noise Shaping Delta-Sigma Modulator

이재성,노정진 한국과학기술원 반도체설계교육센터 2016 IDEC Journal of Integrated Circuits and Systems Vol.2 No.3

This paper presents a multi stage noise shaping (MASH) delta-sigma modulator (DSM) for high speed data signal processing. This delta-sigma modulator (DSM) is discrete-time modulator (DT) and sampling of the input signal occurs prior to the loop filter. Discrete-time (DT) modulator has lower performance degradation from excess loop delay, clock jitter, process variation than Continuous-time (CT) modulator. A 4-Phase buck converter is used to supply power in delta-sigma modulator (DSM). The delta-sigma modulator (DSM) power supply is 1.8V. The buck converter has low EMI using spread spectrum. To implement spread spectrum, the paper proposes random clock generator. The buck converter supply voltage 3V and Output voltage is 1.8V. Switching frequency ranges from 7 to 9 MHz and Maximum load current is 500mA. The delta-sigma modulator (DSM) and buck converter is fabricated in 0.18㎛ CMOS process and circuit type is Mixed-design.

Frequency Response 법에 의한 알카리금속 증기와 알곤의 열전도 도측정에 관한 연구

이재성 한국화학공학회 1969 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.7 No.2

The Frequency response to alternating current of a fine wire surrounded by alkali metal vapor was studied theoretically and experimentally for determining the thermal conductivity of the vapor. Data were obtained for cesium and rubidium vapors at pressures from 0.0829 to 0.214 atm. A new method was employed of correcting for temperature jump and vapor volumetric heat capacity. The reliability of the method is indicated by agreement with literature values for argon up to 1085℃. The standard error of the argon correlation is estimated at 1.6%, and the total probable experimental error in the cesium and rubidium vapor measurements is estimated at 5.1%.

창구응대 서비스 향상으로 인한 고객감동

김정수,김은희,외14명,이재성 한국의료QA학회 2007 가을학술대회 Vol.2007 No.3

Evaluation of a Fast Photomultiplier Tube for Time-of-Flight PET

이재성,이진표,Mikiko Ito 대한의용생체공학회 2011 Biomedical Engineering Letters (BMEL) Vol.1 No.3

Purpose Adding time-of-flight (TOF) information to positron emission tomography (PET) can lead to an improvement in image quality because TOF information allows the estimation of gamma ray annihilation positions in three dimensions. For accurate position estimation, precise time resolution is the most important characteristic required of TOF-PET detectors. The aims of this study were to establish the optimal setup for timing measurements and to evaluate the timing performance of a fast photomultiplier tube (PMT) (Hamamatsu R9800)coupled with a lutetium yttrium orthosilicate (LYSO)scintillation crystal for TOF-PET detector development. Methods Performance of a fast PMT (diameter, 25 mm;length, 55 mm) coupled with a LYSO crystal (4 × 4 × 10mm3) was measured in coincidence experiments with 511 keV annihilation photons from a 22Na gamma source. Timing measurement optimization was carried out with a leadingedge discriminator (LED) and a constant fraction discriminator (CFD). Results Results showed the optimal timing resolution could be obtained with a CFD time delay of 1 ns; timing resolutions (FWHM) of the LYSO crystal-coupled fast PMT were measured to be 198 and 254 ps for two different R9800PMTs. The energy resolutions at 511 keV were 10.8% and 10.6%, respectively. Additional experiments to determine the position uncertainty were performed at three different source positions and the position uncertainty (FWHM) in the TOF measurement using these PMTs was estimated to be 4.50 cm. Conclusions The performance of fast R9800 PMT coupled with a LYSO crystal showed good potential for development as a TOF-PET detector module.

<프랑스의 자국어 교과서 교과서 분석 연구>에 대한 토론문

이재성 한국문법교육학회 2011 한국문법교육학회 학술발표논문집 Vol.2011 No.2

영-한 병렬 코퍼스로부터 외래어 표기 사전의 자동 구축

이재성 한국컴퓨터교육학회 2003 컴퓨터교육학회 논문지 Vol.6 No.2

본 논문에서는 한국어 번역문과 영어 원문으로 구성된 병렬 코퍼스로부터 자동으로 외래어 표기 사전을 구축하는 시스템을 제안한다. 구축 시스템은 첫 단계로 한국어 문서에서 명사를 추출하고, 두 번째 단계에서 추출된 명사 중 언어 모델에 근거하여 외래어만을 추출한 후, 마지막 세 번째 단계에서 확률적 정렬 방법을 이용하여 외래어에 대응되는 영어를 추출한다. 특히, 외래어는 한국어 어미나 조사가 붙어서 같이 쓰이기 때문에, 한국어 어절 내에서 정확하게 외래어 부분만을 분리하기 위해, 병렬 코퍼스 내에 존재하는 대응 영어 단어 정보를 활용하였다. 또, 문자체계가 다른 두 단어를 같은 문자로 변환하지 않고 직접 음운 유사도를 비교할 수 있도록 했다. 실험 결과, 성능은 전처리 단계인 한국어 미등록어 및 외래어 추정에 영향을 많이 받았고, 수작업으로 전처리를 한 모델 중 가장 성능이 높은 것은 재현률 85.4%, 정확률 91.0%를 보였고, 전 과정을 자동으로 한 모델중에서는 재현률 68.3%, 정확률 89.2%를 보였다. This paper proposes an automatic construction system for transliteration dictionary from English-Korean parallel corpus. The system works in 3 steps: it extracts all nouns from Korean documents as the first step, filters transliterated foreign word nouns out of them with the language identification method as the second step, and extracts the corresponding English words by using a probabilistic alignment method as the final step. Specially, the fact that there is a corresponding English word in most cases, is utilized to extract the purely transliterated part from a Koreans word phrase, which is usually used in combined forms with Korean endings(Eomi) or particles(Josa). Moreover, the direct phonetic comparison is done to the words in two different alphabet systems without converting them to the same alphabet system. The experiment showed that the performance was influenced by the first and the second preprocessing steps: the most efficient model among manually preprocessed ones showed 85.4% recall, 91.0% precision and the most efficient model among fully automated ones got 68.3% recall, 89.2% precision.

황산처리된 산화철 촉매의 특성

이재성,박두선 한국화학공학회 1990 NICE Vol.8 No.3