• Molecules and Cells
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• 제38권6호
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• pp.580-586
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• 2015

While increasing evidence indicates the important function of histone methylation during development, how this process influences cardiac development in vertebrates has not been explored. Here, we elucidate the functions of two histone H3 lysine 4 (H3K4) methylation enzymes, SMYD3 and SETD7, during zebrafish heart morphogenesis using gene expression profiling by whole mount in situ hybridization and antisense morpholino oligonucleotide (MO)-based gene knockdown. We find both smyd3 and setd7 are highly expressed within developing zebrafish heart and knock-down of these genes led to severe defects in cardiac morphogenesis without altering the expressions pattern of heart markers, including cmlc2, vmhc, and amhc. Furthermore, double knock-down by coinjection of smyd3 and setd7 MOs caused the synergistic defects in heart development. As similar to knock-down effect, overexpression of these genes also caused the heart morphogenesis defect in zebrafish. These results indicate that histone modifying enzymes, SMYD3 and SETD7, appear to function synergistically during heart development and their proper functioning is essential for normal heart morphogenesis during development.

• 대한기계학회논문집B
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• 제37권4호
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• pp.387-394
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• 2013

온실가스인 $CO_2$ 배출을 줄이기 위한 연료로서 고효율 연소의 특성을 갖는 수소-천연가스 혼합연료(HCNG)가 유력한 미래 대체연료로서 주목받고 있다. 일반적으로 엔진에서의 압축비 상승은 효율 향상 및 이산화탄소 배출 저감을 위한 방법 중의 하나로서 HCNG 엔진에서도 고압축비의 적용이 효과적일 수 있으나, 수소의 높은 연소 속도 및 화염 온도로 인한 조기착화, 노킹 등의 이상연소는 엔진 부품의 파손 및 출력 저하를 초래할 수 있다. 본 연구는 HCNG 엔진에서 압축비를 변경하여 엔진 성능 및 노킹 특성을 분석하는데 목적이 있다. 기존의 CNG 엔진에 CNG 및 HCNG 연료를 적용하여 공기과잉률의 변화에 따른 연소 특성을 분석하고, 압축비 변경 후 엔진의 성능에 미치는 영향을 파악하였다.

• 무역학회지
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• 제42권5호
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• pp.19-42
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• 2017

오늘날 일반적으로 국제상거래에서는 매수인과 매도인이 표준화된 서식을 이용하여 서로 거래한다. 서식분쟁은 이러한 서식의 교환의 결과이다. 서식분쟁에서 해결되어야 하는 몇 가지 문제들이 있다. 예를 들어, 상이한 조건의 교환으로 계약이 성립하는가? 계약조건은 무엇인가? 어느 당사자의 조건을 적용할 것인가? 누구의 것인가? 등이다. 2015년, 헤이그 국제사법회의는 헤이그준거법원칙을 최종적으로 승인하였다. 해당 원칙은 서식분쟁을 다루고 있다. 또한 2013년, CISG 자문위원회는 CISG에 의거한 표준조건의 편입과 관련한 문제를 해결하기 위한 효과적인 방법을 제기하기 위하여 "Black letter rules"를 채택하였다. 본 연구는 헤이그준거법원칙과 CISG에서 서식분쟁을 관련 규정과 사례를 종합적으로 검토하였다. 본 연구의 목적은 양당사자의 서식분쟁 문제를 해결하기 위한 적절한 실무적 해결방안을 제안하는 데 있다.

• 한국광과학회:학술대회논문집
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• 한국광과학회 2002년도 정기총회 및 제9회 광과학 학술심포지움 논문초록
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• pp.47-47
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• 2002

• Molecules and Cells
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• 제41권5호
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• pp.454-464
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• 2018

Crosstalk between G-protein signaling and glutamatergic transmission within the brain reward circuits is critical for long-term emotional effects (depression and anxiety), cravings, and negative withdrawal symptoms associated with opioid addiction. A previous study showed that Regulator of G-protein signaling 4 (RGS4) may be implicated in opiate action in the nucleus accumbens (NAc). However, the mechanism of the NAc-specific RGS4 actions that induce the behavioral responses to opiates remains largely unknown. The present study used a short hairpin RNA (shRNA)-mediated knock-down of RGS4 in the NAc of the mouse brain to investigate the relationship between the activation of ionotropic glutamate receptors and RGS4 in the NAc during morphine reward. Additionally, the shRNA-mediated RGS4 knock-down was implemented in NAc/striatal primary-cultured neurons to investigate the role that striatal neurons have in the morphine-induced activation of ionotropic glutamate receptors. The results of this study show that the NAc-specific knock-down of RGS4 significantly increased the behaviors associated with morphine and did so by phosphorylation of the GluR1 (Ser831) and NR2A (Tyr1325) glutamate receptors in the NAc. Furthermore, the knock-down of RGS4 enhanced the phosphorylation of the GluR1 and NR2A glutamate receptors in the primary NAc/striatal neurons during spontaneous morphine withdrawal. These findings show a novel molecular mechanism of RGS4 in glutamatergic transmission that underlies the negative symptoms associated with morphine administration.

• 생명과학회지
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• 제12권2호
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• pp.219-225
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• 2002

진핵세포의 염색체는 전사, 복제, 회복 등의 과정에서 관여하는 단백질의 기능으로 구조가 변하게 된다. 이때 관여하는 단백질은 DNA-단백질의 상호작용에 의해서 이루어지게 되는데, 이때 단백질의 일부분은 일정한 상동성이 존재하게 된다. 이러한 부분은 motif나 domain으로 구성되는데, 예를 들면, SAP domain등을 들 수 있다. S. pombe genomic DNA 데이터베이스를 검색하여 Arabidopsis PARP 과 KU70과 상동성을 보이는 새로운 유전자를 찾았다. 이를 SAPuvs (SAP UV Sensitive)라 명명하였으며, Ura4를 선별표지로 이용하여 S. pombe SAPuvs 유전자 결실세포를 구성하였다. SAPuvs 유전자 결실세포는 자외선 조사 실험에서 정상의 세포에 비해 현저하게 죽었다. 그러나, MMS 또는 MMS와 3AB의 처리 실험에서는 저항성을 보였다. 이러한 결과로 SAPuvs는 DNA 상해회복에서 염색사구조 형성에 연관되어 있음을 확인하였다.

• Reproductive and Developmental Biology
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• 제38권2호
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• pp.71-77
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• 2014

The specific genetic modification in porcine somatic cells by gene targeting has been very difficult because of low efficiency of homologous recombination. To improve gene targeting, we designed three kinds of knock-out vectors with ${\alpha}1,3$-galactosyltransferase gene (${\alpha}1,3$-GT gene), DT-A/pGT5'/neo/pGT3', DT-A/NLS/pGT5'/neo/pGT3' and pGT5'/neo/ pGT3'/NLS. The knock-out vectors consisted of a 4.8-kb fragment as the 5' recombination arm (pGT5') and a 1.9-kb fragment as the 3' recombination arm (pGT3'). We used the neomycin resistance gene (neo) as a positive selectable marker and the diphtheria toxin A (DT-A) gene as a negative selectable marker. These vectors have a neo gene insertion in exon 9 for inactivation of ${\alpha}1,3$-GT locus. DT-A/pGT5'/neo/pGT3' vector contain only positive-negative selection marker with conventional targeting vector. DT-A/NLS/pGT5'/neo/pGT3' vector contain positive-negative selection marker and NLS sequences in upstream of 5' recombination arm which enhances nuclear transport of foreign DNA into bovine somatic cells. pGT5'/neo/pGT3'/NLS vector contain only positive selection marker and NLS sequence in downstream of 3' recombination arm, not contain negative selectable marker. For transfection, linearzed vectors were introduced into porcine ear fibroblasts by electroporation. After 48 hours, the transfected cells were selected with $300{\mu}g/ml$ G418 during 12 day. The G418-resistant colonies were picked, of which 5 colonies were positive for ${\alpha}1,3$-GT gene disruption in 3' PCR and southern blot screening. Three knock-out somatic cells were obtained from DT-A/NLS/ pGT5'/neo/pGT3' knock-out vector. Thus, these data indicate that gene targeting vector using nuclear localization signal and negative selection marker improve targeting efficiency in porcine somatic cells.

• 한국수정란이식학회지
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• 제27권1호
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• pp.9-14
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• 2012

This study was conducted to analyze the transgenic efficiency and sex ratio in ${\alpha}$-1,3-galactosyltransferase (GalT) knock-out (KO) transgenic pigs according to generation. GalT KO piglets were produced by artificial insemination or natural mating. The transgenic confirmation of GalT KO was evaluated by PCR amplification using specific primers. After electrophoresis, three types of bands were detected such as 2.3 kb single band (Wild), 2.3 and 3.6kb double bands (GalT KO -/+; heterozygote), and 3.6kb single band (GalT KO -/-; homozygote). Transgenic efficiency in F1 generation was 64.5% (23/35) of GalT KO (-/+). In F2 generation, GalT KO transgenic efficiency was 36.4% (21/57, Wild), 47.5% (28/57, GalT KO -/+), and 16.1% (8/57, GalT KO -/-), respectively. Interestingly, no homozygote piglets were born in 6 deliveries among total 11 deliveries, although they were pregnant between male (M) and female (F) $F_1$ heterozygote. In the 5 litters including at least one GalT KO -/- piglet, the transgenic efficiency was 13.3% (2/24, Wild), 51.3% (14/24, GalT KO -/+), and 35.3% (8/24, GalT KO -/-), respectively. The sex ratio of M and F was 40:60 in $F_1$ and 49:51 in $F_2$ generation, respectively. Based on these results, GalT KO transgenic pigs have had a reproductive ability with a normal range of transgenic efficiency and sex ratio.

• Reproductive and Developmental Biology
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• 제35권3호
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• pp.385-390
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• 2011

The purpose of this study was undertaken to evaluate of cryopreservation efficiency in ${\alpha}$ 1,3-galactosyltransferase knock-out(GalT KO) cloned miniature pig sperm. To compare ability of frozen-thawed sperm characteristics, three different pig strains (GalT KO) cloned miniature pig, PWG miniature pig and Duroc were used. The ejaculated semen from the three pig species was diluted with same volume extender and added to LEY solution for freezing. The diluted semen was placed in 0.5 ml straws, and freezing was initiated by exposing the straws to liquid nitrogen ($LN_2$) vapours for 10 min before placing them into $LN_2$ for cryopreservation. After thawing, the sperm ability were assessed for viability (SYBR-14/PI staining), abnormality (Rose Bengal staining), and acrosome status (intactness, intensity and capacitation) (chlorotetracycline, CTC staining). The viability of frozen-thawed GalT KO pig sperm had no significant difference as compared with Duroc and PWG miniature pig sperm. However, The CTC pattern of frozen-thawed GalT KO cloned miniature pig spermatozoa showed significantly lower rates in F pattern and AR pattern (p<0.05) and significantly higher rates in B pattern than Duroc and PWG miniature pig (p<0.05). The abnormality of GalT KO cloned miniature pig sperm was significantly lower as compared to Duroc and PWG miniature pig sperm (p<0.05). In conclusion, GalT KO cloned miniature pig semen can be cryopreserved successfully and used for artificial insemination reasonably.

• 한국경영과학회지
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• 제38권3호
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• pp.37-50
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• 2013

The purpose of this study is to determine the indicators and the criteria to classify types of train delays of high-speed rail in South Korea. Types of train delays have divided into the chronic delays and the knock-on delays. The Indicators based on relevance, reliability, and comparability were selected with arrival delay rate of over five minutes, median of arrival delays of preceding train and following train, knock-on delay rate of over five minutes, correlation of delay between preceding train and following train on intermediate and last stations, average train headway, average number of passengers per train, and average seat usages. Types of train delays were separated using the Ward's hierarchical cluster analysis. The criteria for classification of train delay were presented by the Fisher's linear discriminant. The analysis on the situational characteristics of train delays is as follows. If the train headway in last station is short, the probability of chronic delay is high. If the planned running times of train is short, the seriousness of chronic delay is high. The important causes of train delays are short headway of train, shortly planned running times, delays of preceding train, and the excessive number of passengers per train.