• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.99-101
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• 2014

A Comprehensive Vibration Assessment Program (CVAP) for steam generator internals (SGI) of Advanced Power Reactor 1400 (APR1400) is being performed in accordance with the United States Nuclear Regulatory Commission (U.S. NRC) Regulatory Guide 1.20 (RG 1.20) revision 3. This paper studies the vibration characteristics of moisture separator assembly as part of the vibration and stress analysis program for APR1400 SGI CVAP. The natural frequencies, mode shapes, and structural behavior of moisture separator assembly were investigated through modal analysis using finite element method and experimental measurement. Since the moisture separator consists of several items with complicated shape, an idealized shell model was used in the finite element analysis. Group of local modes caused by moisture separators and significant modes of shroud and separator support plate were identified. The results of this paper are to be utilized in the structural response analysis of moisture separator assembly.

• BMB Reports
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• 제38권4호
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• pp.500-506
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• 2005

HOX11 encodes a homeodomain-containing transcription factor which directs the development of the spleen during embryogenesis. While HOX11 expression is normally silenced through an unknown mechanism in all tissues by adulthood, the deregulation of HOX11 expression is associated with leukemia, such as T-cell acute lymphoblastic leukemia. The elucidation of regulatory elements contributing to the molecular mechanism underlying the regulation of HOX11 gene expression is of great importance. Previous reports of HOX11 regulatory elements mainly focused on the 5'-flanking region of HOX11 on the chromosome related to transcriptional control. To expand the search of putative cis-elements involved in HOX11 regulation at the post-transcriptional level, we analyzed HOX11 mRNA 3'-untranslated region (3'UTR) and found an AU-rich region. To characterize this AU-rich region, in vitro analysis of HOX11 mRNA 3'UTR was performed with human RNA-binding protein HuR, which interacts with AU-rich element (ARE) existing in the 3'UTR of many growth factors' and cytokines' mRNAs. Our results showed that the HOX11 mRNA 3'UTR can specifically bind with human HuR protein in vitro. This specific binding could be competed effectively by typical ARE containing RNA. After the deletion of the AU-rich region present in the HOX11 mRNA 3'UTR, the interaction of HOX11 mRNA 3'UTR with HuR protein was abolished. These findings suggest that HOX11 mRNA 3'UTR contains cis-acting element which shares similarity in the action pattern with RE-HuR interactions and may involve in the post-transcriptional regulation of the HOX11 gene.

• The Plant Pathology Journal
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• 제17권3호
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• pp.115-122
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• 2001

Potato virus X (PVX) is a flexuous rod-shaped virus containing a single plus-strand RNA. Viral RNA synthesis is precisely regulated by regulatory viral sequences and by viral and/or host proteins. RNA sequence element as well as stable RNA stem-loop structure in the 5' end of the genome affect accumulation of genomic RNA and subgenomic RNA (sgRNA). The putative sgRNA promoter regions upstream of the PVX triple gene block (TB) and coat protein (CP) gene were critical for both TB and CP sgRNA accumulation. Mutations that disrupted complementarity between a region at the 5' end of the genomic RNA and the sequences located upstream of each sgRNA initiation site is important for PVX RNA accumulation. Compensatory mutations that restore complementarity restored sgRNA accumulation levels. However, the extent of reductions in RNA levels did not directly correlate with the degree of complementarity, suggesting that the sequences of these elements are also important. Gel-retardation assays showed that the 5' end of the positive-strand RNA formed an RNA-protein complex with cellular proteins, suggesting possible involvement of cellular proteins for PVX replication. Future studies on cellular protein binding to the PVX RNA and their role in virus replication will bring a fresh understanding of PVX RNA replication.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4083-4095
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• 2023

Currently, various research institutes in Korea are conducting research to develop a safety case for deep geological repository for high-level radioactive waste (HLW). In the past, low and intermediate-level waste (LILW) was approved by a regulatory body by performing a post-closure safety assessment, but HLW has different disposal characteristics and safety objectives are different. Therefore, in the case of HLW, safety assessment should be performed based on these changed conditions, and specific procedures are also under development. In this paper, the regulatory status of prior research institutes, feature, event and process (FEP) and scenario development cases were investigated for well-organized FEP and scenario development methodologies. In addition, through the results of these surveys, the requirements and procedures necessary for the FEP and scenario development stage during the safety assessment of repository for HLW were presented. These review results are expected to be used to identify the overall status of previous studies in conducting post-closure risk assessment for HLW repository, starting with identifying regulatory requirements, the most basic element.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 제3회 추계심포지움
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• pp.9-15
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• 1995

When quiescent cells ate stimulated to enter the cell cycle, the thymidine kinase(TK) gene is transcriptionally activated at the border of Gl and 5. In this report we show that the human TK promoter contains multiple protein-binding sites. By site-directed mutagenesis, we identified a protein-binding site on the human TK promoter requited for conferring Gl-S-regulated transcription to a heterologous promoter and dissociated it functionally from an adjacent protein-binding domain containing an inverted CCAAT motif requited for high basal level expression. Substitution-mutation of this site results in constitutive expression of the neo reporter gene in serum-stimulated fibroblasts, as well as in cells arrested in mid-Gl by a temperature-sensitive mutation. The regulatory domains for the human TK promoter exhibit interesting symmetrical features, including a set of CCAAT motifs and sites similar to the novel Yi protein-binding site recently discovered in the mouse TK promoter. Thus, components of the hTK complex is important for hTK gene regulation.

• Bioinformatics and Biosystems
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• 제2권2호
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• pp.52-57
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• 2007

The computational discovery of transcription factor binding site is one of the important tools in the genetic and genomic analysis. Rough prediction of gene regulation network and finding possible co-regulated genes are typical applications of the technique. Countless motif-discovery algorithms have been proposed for the past years. However, there is no dominant algorithm yet. Each algorithm does not give enough accuracy without extensive information. In this paper, we explore the possibility of combining multiple algorithms for the one integrated result in order to improve the performance and the convenience of researchers. Moreover, we apply new high order information that is reorganized from the set of basis predictions to the final prediction.

• 한국해양공학회지
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• 제38권3호
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• pp.87-102
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• 2024

Given the inadequate regulatory framework for liquefied hydrogen gas storage tanks on ships and the limitations of the IGC Code, designed for liquefied natural gas, this study introduces a critical assessment procedure to ensure the safety and suitability of such tank designs. This study performed a heat transfer analysis for boil-off gas (BOG) calculations and established separate design load cases to evaluate the yielding and buckling strength. In addition, the study assessed methodologies for both high-cycle and low-cycle fatigue assessments, complemented by comprehensive structural integrity evaluations using finite element analysis. A comprehensive approach was developed to assess the structural integrity of Type C tanks by conducting crack propagation analysis and comparing these results with the IGC Code criteria. The practicality and efficacy of these methods were validated through their application on a 23K-class liquefied hydrogen carrier at the concept design stage. These findings may have important implications for enhancing safety standards and regulatory policies.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.309-316
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• 2024

The U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.20 provides guidance on the comprehensive vibration assessment program (CVAP) to be performed on reactor internals during preoperational and startup tests. The purpose of the program is to identify loads that could cause vibration in the reactor internals and to ensure that these vibrations do not affect their structural integrity. The structural vibrational analysis program involves creating finite element analysis models of the reactor internals and calculating their structural responses when subjected to vibration loads. The appropriateness of the structural analysis methodology must be demonstrated through benchmarks or any other reasonable means. Although existing structural analysis methodologies have been proven to be appropriate and are widely used, this paper presents the development of an improved new structural analysis methodology for APR1400 reactor internals using scaled model tests.

• The Korean Journal of Physiology and Pharmacology
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• 제3권2호
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• pp.157-164
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• 1999

To determine molecular mechanisms of Aquaporin-CD (AQP2) gene regulation, the promoter region of the AQP2 gene was examined by transiently transfecting a promoter-luciferase reporter fusion gene into mouse renal collecting duct cell lines such as mIMCD-3, mIMCD-K2, and M-1 cells, and NIH3T3 mouse embryo fibroblast cells. PCR-Southern analysis reveals that mIMCD-3 and mIMCD-K2 cells express AQP2, but M-1 and NIH3T3 cells do not, and that the treatment with cpt-cAMP $(400\;{\mu}M)$) or forskolin/isobutylmethylxanthine (IBMX) increased the AQP2 expression in IMCD cells. In both IMCD and NIH3T3 cells, the constructs containing the promoter of AQP2 gene showed promoter activities, indicating lack of tissue-specific element in the 1.4 kb 5'-flanking region of the mouse AQP2 gene. Luciferase activity in the IMCD cells transfected with the construct containing 5-flanking region showed responsiveness to cpt-cAMP, indicating that the 1.4 kb 5'-flanking region contains the element necessary for the regulatory mechanism by cAMP. The promoter-luciferase constructs which do not have a cAMP-responsible element (CRE) still showed the cAMP responsiveness in IMCD cells, but not in NIH3T3 cells. Increase in medium osmolarity did not affect AQP2 promoter activity in mIMCD-K2 cells. These results demonstrate that AQP2 gene transcription is increased with cAMP treatment through multiple motifs including CRE in the 5'-flanking region of the gene in vitro, and the regulatory mechanism may be important for in vivo regulation of AQP2 expression.

• BMB Reports
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• 제54권2호
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• pp.106-111
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• 2021

Hemistepsin A (HsA) is a guaianolide sesquiterpene lactone that inhibits hepatitis and liver fibrosis. We evaluated the effects of HsA on liver X receptor (LXR)-mediated hepatic lipogenesis in vitro and in vivo. Up to 10 μM, HsA did not affect the viability of HepG2 and Huh7 cells. Pretreatment with 5-10 μM HsA significantly decreased the luciferase activity of the LXR response element, which was transactivated by T0901317, GW 3965, and LXRα/retinoid X receptor α overexpression. In addition, it significantly inhibited the mRNA expression of LXRα in HepG2 and Huh7 cells. It also suppressed the expression of sterol regulatory element-binding protein-1c and lipogenic genes and reduced the triglyceride accumulation triggered by T0901317. Intraperitoneal injection of HsA (5 and 10 mg/kg) in mice significantly alleviated the T0901317-mediated increases in hepatocyte diameter and the percentage of regions in hepatic parenchyma occupied by lipid droplets. Furthermore, HsA significantly attenuated hepatic triglyceride accumulation by restoring the impaired expression of LXRα-dependent lipogenic genes caused by T0901317. Therefore, based on its inhibition of the LXRα-dependent signaling pathway, HsA has prophylactic potential for steatosis.