• Title/Summary/Keyword: Hinge region

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Leucine Zipper as a Fine Tuner for the DNA Binding; Revisited with Molecular Dynamics Simulation of the Fos-Jun bZIP Complex

  • 최용훈;양철학;김현원;정선호
    • Bulletin of the Korean Chemical Society
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    • v.20 no.11
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    • pp.1319-1322
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    • 1999
  • Leucine zipper dynamically tunes the degree of bifurcation of the DNA binding segments in the basic region of the Fos-Jun bZIP complex. Molecular dynamics simulation indicated that site-specific mutagenesis of conserved leucine residues inside the leucine zipper domain caused the change of dynamic behavior of the basic region, and efficient DNA binding occurs only within a certain range of distance between the two DNA binding segments in the basic region. Distribution of α-helices in the hinge region is also suggested to influence the bifurcation of the DNA binding segments.

Seismic Performance Evaluation of Shear-Critical R/C Bridge Piers Retrofitted with Fiber Sheets (섬유 보강된 휨전단 RC교각의 내전성능 평가)

  • 송호진;정영수;김용곤;이은희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.195-202
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    • 2002
  • Lap splices of longitudinal reinforcement steels were practically located in the potential plastic hinge region of most bridge columns that were constructed before the 1992 seismic design provision of Roadway Bridge Design Specification in Korea. The objective of this research is to evaluate the seismic performance of shear-critical reinforced concrete(RC) bridge piers with poor detailing of the starter bars in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity by retrofitting with fiber composites. Seven test specimens in the aspect ratio of 2.5 were made with three confinement ratios and two types of lap splices. Quasi-static test was conducted in a displacement-controlled test mode. A significant reduction of displacement ductility ratios were observed for test columns with lap splices of longitudinal steels.

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Quasi-Static Test for Seismic Performance of R/C Bridge Piers with Lap Splices (준정적실험에 의한 겹이음된 철근콘크리트 교각의 내진성능 평가)

  • Chung, Young-Soo;Lee, Jae-Hyung;Kim, Yong-Gon;Kim, Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.877-882
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    • 2001
  • Lap splice in plastic hinge region of RC bridge piers is inevitable because of the constructional joint between footing and column. RC circular columns with lap-splice in plastic hinge region are widely used in Korean highway bridges. It is, however, believed that there are not many experimental research works for nonlinear behavior of these columns subjected to earthquake motions. This study has been performed to verify the effect of axial force, lap splice and confinement steel ratio for the seismic behaviour of reinforced concrete bridge piers. Quasi-static test have been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility and enemy absorption.

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Seismic Performance of Flexural-Shear Circular Reinforced Concrete Bridge Piers (휨전단 거동을 보이는 원형 RC교각의 내진성능평가)

  • Song, Ho-Jin;Chung, Young-Soo;Kim, Yon-Gon;Kim, Hoon;Kim, Dae-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.823-828
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    • 2002
  • Lap splice in plastic hinge region of RC bridge piers is inevitable because of the constructional joint between footing and column. RC circular columns with lap-splice in plastic hinge region are widely used in Korean highway bridges. It is, however, believed that there we not many experimental research works for nonlinear behavior of these columns subjected to earthquake motions. This study has been peformed to verify the effect of lap splice and confinement steel ratio for the seismic behaviour of reinforced concrete bridge piers. Quasi-static test have been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility.

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Stability and Structural Change of cAMP Receptor Protein at Low and High cAMP Concentrations

  • GANG JONGBACK;CHUNG HYE-JIN;PARK GWI-GUN;PARK YOUNG-SEO;CHOI SEONG-JUN
    • Journal of Microbiology and Biotechnology
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    • v.15 no.6
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    • pp.1392-1396
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    • 2005
  • Proteolytic digestion and CD measurement of wild-type and mutant cyclic AMP receptor proteins (CRPs) were performed either in the presence or absence of cyclic nucleotide. Results indicated that transition of a structural change to the hinge region by the binding of cAMP to the anti site was required for the binding of cAMP to the syn site near the hinge region and, although the occupancy of cAMP in the anti site increased the protein stability, CRP adopted more a stable conformation by the binding of cAMP to the syn site.

Ductility Assesment of Damaged RC Bridge Piers w with Lap-Spliced Bars

  • Chung, Young-Soo;Park, Chang-Kyu;Lee, Eun-Hee
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.453-456
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    • 2003
  • This research is to evaluate the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal reinforcement steels in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity. Six circular columns of 0.6m diameter and 1.5m height were made with two confinement steel ratios. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading simultaneously under an axial load, P=$0.1f_{ck}A_{g}$, and residual seismic performance of damaged columns was evaluated. Test results show that RC bridge piers with lap-spliced longitudinal steels behaved with minor damage even under artificial earthquakes with 0.22g PGA, but failed at low ductility subjected to the subsequent quasi-static load test. This failure was due to the debonding of the lap splice. The specimens externally wrapped with composite FRP straps in the potential plastic hinge region showed significant improvement both in flexural strength and displacement ductility.

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Seismic Retrofit of RC Columns with Lap-Spliced Longitudinal Rebars Wrapping by SMA Wires (SMA Wire를 이용한 주철근 겹침이음된 RC 교각의 내진 보강 연구)

  • Park, Yong-Kwon;Lee, Yeon-Hun;Yang, Dong-Wook;Lim, Hyeon-Sik;Chung, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.129-130
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    • 2010
  • Lap splice of longitudinal reinforcing steels was located in the plastic hinge region of most bridge piers that had been designed and constructed before the adoption of the 1992 seismic design provision of Korea Highway Design Specification. This research aims at improving the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, of which the plastic hinge region was wrapped by the shape memory alloy (SMA) wires. Quasi-static test was used to investigate the seismic behaviours of RC test specimens.

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Shear Ductile Capacity of Reinforced Concrete Beams Subjected to Reversed Cyclic Loading (반복 하중을 받는 철근콘크리트 보의 전단 연성)

  • Na, Hyun-Jong;Lee, Jung-Yoon;Hwang, Hyun-Bok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.285-288
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    • 2006
  • This paper provides a method to predict the ductile capacity of reinforced concrete beams that fail in shear after flexural yielding. The proposed method takes into account shear strength deterioration in the plastic hinge region of RC beams. The shear contribution of the concrete in the plastic hinge region decreases after flexural yielding of the beam due to a decrease in the effective compressive strength of the concrete. To verify the shear strength and the corresponding ductility of the proposed method, 8 RC beams were tested under reversed cyclic loading.

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Disulfide Bond Bridged Divalent Antibody-Toxin, $(Fab-PE38fl)_2$ with the Toxin PE38 Fused to the Light Chain

  • Won, Jae-Seon;Choe, Mu-Hyeon
    • Journal of Microbiology and Biotechnology
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    • v.18 no.8
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    • pp.1475-1481
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    • 2008
  • B3 antibody specifically binds the $Lewis^Y$-related carbohydrate antigen of many carcinomas, and it is used as a model antibody in this study. In a previous study, the Fab fragment of the antibody was fused to a 38 kDa truncated form of Pseudomonas exotoxin A, PE38, to make Fab-PE38, where PE38 is fused to the Fd fragment of the Fab domain. This parent monomer molecule, Fab-PE38, had no cysteine in the hinge region, and it could not make a disulfide bond to form a disulfide bond bridged homodimer. In this study, we constructed three different kinds of divalent Fab-toxin fusion homodimers where the toxin is fused to the light chain of Fab, $(Fab-PE38fl)_2$. In addition to the PE38 toxin fused to the light chain, these three molecules have different hinge sequences hi, h2, and h3 making Fabh1-, Fabh2-, and Fabh3-PE38fl monomers, respectively. These hinges contain only one cysteine on different positions of the hinge sequence. The disulfide bond between the hinge region of two monomers forms homodimers $(Fabh1-PE38fl)_2$, $(Fabh2-PE38fl)_2$, and $(Fabh3-PE38fl)_2$. The refolding yields of these dimers were 5-16-fold higher than a previously constructed dimer where the PE38 was fused to the Fd fragment $(Fabh2-PE38)_2$ [8]. Our data suggest that the steric repulsion between the two PE38s in $(Fabh1-PE38)_2$ during disulfide bridge formation is relieved by fusing it at the end of the light chain. The best cytotoxicity value of these dimers showed about 2.5-fold higher on an MCF7 cell line than that of the monovalent reference molecule in ng/ml scale, which is 15-fold higher in pM scale.

Design for moment redistribution in FRP plated RC beams

  • Oehlers, Deric John;Hasketta, Matthew;Mohamed Ali, M.S.
    • Structural Engineering and Mechanics
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    • v.38 no.6
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    • pp.697-714
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    • 2011
  • Assessing the ductility of reinforced concrete sections and members has been a complex and intractable problem for many years. Given the complexity in estimating ductility, members are often designed specifically for strength whilst ductility is provided implicitly through the use of ductile steel reinforcing bars and by ensuring that concrete crushing provides the ultimate limit state. As such, the empirical hinge length and neutral axis depth approaches have been sufficient to estimate ductility and moment redistribution within the bounds of the test regimes from which they were derived. However, being empirical, these methods do not have a sound structural mechanics background and consequently have severe limitations when brittle materials are used and when concrete crushing may not occur. Structural mechanics based approaches to estimating rotational capacities and rotation requirements for given amounts of moment redistribution have shown that FRP plated reinforced concrete (RC) sections can have significant moment redistribution capacities. In this paper, the concept of moment redistribution in beams is explained and it is shown specifically how an existing RC member can be retrofitted with FRP plates for both strength and ductility requirements. Furthermore, it is also shown how ductility through moment redistribution can be used to maximise the increase in strength of a member. The concept of primary and secondary hinges is also introduced and it is shown how the response of the non-hinge region influences the redistribution capacity of the primary hinges, and that for maximum moment redistribution to occur the non-hinge region needs to remain elastic.