• BMB Reports
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• v.55 no.12
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• pp.595-601
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• 2022

Polycomb Repressive Complex 2 (PRC2) exhibits key roles in mammalian development through its temporospatial repression of gene expression. EZH1 or EZH2 is the catalytic subunit of PRC2 that mediates the mono-, di- and tri-methylation of histone H3 lysine 27 (H3K27me1/2/3), H3K27me2/me3 being a hallmark of facultative heterochromatin. PRC2 is a chromatin-modifying enzyme that is recruited to a limited number of "nucleation sites", spreads H3K27 methylation and fosters chromatin compaction. EZH1 and EZH2 exhibit differences in their expression patterns, levels of histone methyltransferase activity (HMT) in the context of PRC2, and DNA/nucleosome binding activity. This suggests that their roles in heterochromatin formation are disparate. Dysregulation of PRC2 activity leads to aberrant gene expression and is implicated in cancer and developmental diseases. In this review, we discuss the distinct function of PRC2/EZH1 and PRC2/EZH2 in the early and late developmental stages. We then discuss the cancers associated with PRC2/EZH1 and PRC2/EZH2.

• Molecules and Cells
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• v.37 no.12
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• pp.841-850
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• 2014

Polycomb group (PcG) proteins are conserved chromatin regulators involved in the control of key developmental programs in eukaryotes. They collectively provide the transcriptional memory unique to each cell identity by maintaining transcriptional states of developmental genes. PcG proteins form multi-protein complexes, known as Polycomb repressive complex 1 (PRC1) and Polycomb repressive complex 2 (PRC2). PRC1 and PRC2 contribute to the stable gene silencing in part through catalyzing covalent histone modifications. Components of PRC1 and PRC2 are well conserved from plants to animals. PcG-mediated gene silencing has been extensively investigated in efforts to understand molecular mechanisms underlying developmental programs in eukaryotes. Here, we describe our current knowledge on PcG-mediated gene repression which dictates developmental programs by dynamic layers of regulatory activities, with an emphasis given to the model plant Arabidopsis thaliana.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.303-303
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• 2022

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.2
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• pp.121-129
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• 2022

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) is an N6-methyladenosine (m⁶A) RNA modification regulator and a key determinant of prem-RNA processing, mRNA metabolism and transportation in cells. Currently, m⁶A reader proteins such as hnRNPA2/B1 and YTHDF2 has functional roles in mice embryo. However, the role of hnRNPA2/B1 in porcine embryogenic development are unclear. Here, we investigated the developmental competence and mRNA expression levels in porcine parthenogenetic embryos after hnRNPA2/B1 knock-down. HhnRNPA2/B1 was localized in the nucleus during subsequent embryonic development since zygote stage. After hnRNPA2/B1 knock-down using double stranded RNA injection, blastocyst formation rate decreased than that in the control group. Moreover, hnRNPA2/B1 knock-down embryos show developmental delay after compaction. In blastocyste stage, total cell number was decreased. Interestingly, gene expression patterns revealed that transcription of Pou5f1, Sox2, TRFP2C, Cdx2 and PARD6B decreased without changing the junction protein, ZO1, OCLN, and CDH1. Thus, hnRNPA2/B1 is necessary for porcine early embryo development by regulating gene expression through epigenetic RNA modification.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.64-70
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• 2008

In case that conventional PRC(Pseudo-Randomized Frequency Carrier) modulation scheme is applied to a three-phase HBML(H-Bridge Multi-Level Inverter), the dominant harmonics spectra appear at twice switching frequency. In this paper, the dominant harmonics spectra spreading effect of the conventional PRC scheme was improved by using three stage MUXs(Multiplexers) and two triangular carriers with fixed frequency which has mutual relation of the twice frequency. To confirm the validity of the improved PRC scheme, the experiment were performed on a 1.5[kw] three-phase HBML based induction motor drives. And, the harmonics spectra of the conventional and improved PRC schemes are compared and discussed.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.4
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• pp.43-48
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• 2015

We studied on pseudo-range correction(PRC) modeling in order to improve differential GNSS(DGNSS) accuracy. The PRC is the range correction information that provides improved location accuracy using DGNSS technique. The digital correction signal is typically broadcast over ground-based transmitters. Sometimes the degradation of the positioning accuracy caused by the loss of PRC signals, radio interference, etc. To prevent the degradation, in this paper, we have designed a PRC model through polynomial curve fitting and evaluated this model. We compared two quantities, estimations of PRC using model parameters and observations from the reference station. In the case of GPS, the average is 0.1m and RMSE is 1.3m. Most of GPS satellites have a bias error of less than ${\pm}1.0m$ and a RMSE within 3.0m. In the case of GLONASS, the average and the RMSE are 0.2m and 2.6m, respectively. Most of satellites have less than ${\pm}2.0m$ for a bias error and less than 3.0m for RMSE. These results show that the estimated value calculated by the model can be used effectively to maintain the accuracy of the user's location. However;it is needed for further work relating to the big difference between the two values at low elevation.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.26 no.3
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• pp.217-225
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• 2015

Objectives : The objective of this study was to compare the Korean Personality Rating Scale for Children (K-PRC) profile between children with attention-deficit hyperactivity disorder (ADHD) and typically developing children. We also aimed to investigate the association of K-PRC and ADHD symptoms. Methods : Ninety-nine youth (age $8.3{\pm}2.4$ years, 72 boys) with ADHD and 84 controls (age $9.2{\pm}2.5$ years, 43 boys) were recruited from the Department of Pediatric Psychiatry of the Asan Medical Center Children's Hospital. Diagnoses of ADHD and comorbid psychiatric disorders were confirmed with the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL). The parents of the subjects completed the ADHD rating scale, and K-PRC. Independent t-tests, analysis of covariance, partial correlation analyses, and Mc Nemar test were used for analysis. Results : Children and adolescents with ADHD showed higher K-PRC scores in verbal development, physical development, depression, delinquency, hyperactivity, family dysfunction and psychoticism. Delinquency and hyperactivity were significantly correlated with parent-rated ADHD rating scales and ADHD scores on K-SADS-PL. The hyperactive/impulsive and combined subtypes showed higher scores on hyperactivity and delinquency than the inattentive subtype, and the inattentive subtype showed higher scores on depression and social dysfunction of the K-PRC. Conclusion : Our results suggest that K-PRC could be used to comprehensively evaluate symptoms, combined psychopathologies, developmental delay and family dysfunction of children with ADHD.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.162-165
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• 2005

종전의 준 랜덤 주파수 캐리어(PRC) 발생기는 스위칭 주파수의 2배 주파수에서 매우 큰 스펙트럼 클러스터가 존재하는 문제점이 있었다. 본 연구에서는 상호 2배 관계를 갖는 고정 주파수의 삼각파 캐리어와 3단계 MUX를 이용하여 종전의 PRC방법의 파워 스펙트럼 확산 성능을 개선하였다. 제안된 방법을 3상 캐스케이드 멀티레벨 인버터에 적용하였으며, PSIM시뮬레이션에 의하여 종전의 방법과 제안된 방법의 파워 스펙트럼을 비교 검토하였다.

• Proceedings of the Korean Society for Information Management Conference
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• 2010.08a
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• pp.21-28
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• 2010

본 연구에서는 PubMed에 등재되었으나 Medical Subject Headings(MeSH)가 부여되지 않은 국내 의학학술지의 문헌을 대상으로 미국국립의학도서관 (NLM: National Library of Medicine)의 Medical Text Indexer(MTI)를 활용하여 MeSH 용어를 추천받은 후, PubMed 레코드의 유사주제문헌 (Relation Citations, PRC)에 부여된 MeSH와의 일치여부를 분석하였다. 또한 논문의 저자가 부여한 키워드(저자키워드)와 PRC MeSH의 일치여부도 비교하였다. PRC MeSH와 MTI MeSH 추천어의 일치율은 주표목이 21.1%였고, 체크태그는 18.1%, 부표목은 16.5%로 나타났다. 우리나라 의학논문에 나타난 저자키워드의 중요한 특징은 MeSH 주표목 위주이고, 체크태그와 부표목은 거의 사용하지 않는 것이다. 따라서 저자키워드와 PRC MeSH 주표목과의 일치율은 23.4%에 이르지만, 체크태그와 부표목의 일치율은 각각 1%, 2.1%였다. 색인전문가가 통제어휘를 사용하여 색인하는 과정에서 PRC와 MTI의 MeSH 주표목과 저자키워드가 일치하는 용어를 주표목으로 부여하고, PRC와 MTI가 추천하는 체크태그와 부표목을 활용하는 등 국내 의학문헌의 MeSH 용어 부여 작업을 반자동화(semi-indexing)하면, 정확하고 신속한 MeSH 부여 작업이 가능할 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8C
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• pp.771-776
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• 2006

We present a suboptimum decoding method for space-time trellis codes, which include maximum $likelihood(ML)^{[1]}$ and principal ratio $combining(PRC)^{[2]}$, over quasi-static flat fading channels. In the proposed scheme, the receive antennas are divided into K groups and the PRC is applied to each group, showing a flexible performances between ML and PRC. When K is determined, we also propose the optimum grouping rules and performance index(PI), which simply anticipate the relative performances. Moreover the performances are also evaluated when receive antennas are correlated. Finally, Computer simulations corroborate those theoretical results.