• Title/Summary/Keyword: linker

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Thermomechanical Properties and Shape Memory Effect of PET-PEG Copolymers Cross-linked with Pentaerythritol

  • Shim, Yong-Shik;Chun, Byoung-Chul;Chung, Yong-Chan
    • Fibers and Polymers
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    • v.7 no.4
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    • pp.328-332
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    • 2006
  • Poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers cross-linked with pentaerythritol, a four-way cross-linker, are prepared to compare their mechanical and shape memory properties with the one cross-linked by glycerol. Composition of PEG and pentaerythritol is varied to search for the one with the best mechanical and shape memory properties. The highest shape recovery rate is observed for the copolymer composed of 30 mol% PEG-200 and 2.5 mol% pentaerythritol. Four-way cross-linking by pentaerythritol significantly improves shape recovery rate and retention of high shape recovery rate after repeated use compared to the one cross-linked by glycerol, a three-way cross-linker, and difference and advantage of additional cross-linking point are discussed.

Intein-mediated expression of Trichoderma reesei Cellobiohydrolase I Cellulose Binding Domain in E. coli (Intein을 이용한 대장균에서의 Trichoderma reesei 유래의 Cellobiohydrolase I 섬유소 결합 도메인의 발현)

  • Choi, Shin-Geon
    • Journal of Industrial Technology
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    • v.36
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    • pp.33-37
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    • 2016
  • Cellulose binding domains (CBDs) of cellulases are thought to assist in the hydrolysis of insoluble crystalline cellulose. To gain sufficient amount of CBDs, the self-cleavable intein tag was used for expression and purification of Trichoderma reesei cellobiohydrolase I CBD in E. coli. Synthetic CBD genes, CBD or linker-CBD were cloned into expression vector pTYB11. Recombinant CBDs were successfully purified by intein mediated purification with an affinity chitin-binding domain. The final yields of recombinant CBD and linker-CBD were 3.2 mg/L and 1.4 mg/L, respectively. The functional bindings of recombinant CBDs were confirmed by Avicel binding experiments. The simple and easy purification method using self-cleavable intein tag can be further used in pretreatment of crystalline cellulose or characterization of engineered CBDs.

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Conformal Zinc Oxide Thin Film Deposition on Graphene using molecular linker by Atomic Layer Deposition

  • Park, Jin-Seon;Han, Gyu-Seok;Jo, Bo-Ram;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.280.2-280.2
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    • 2016
  • The graphene, a single atomic sheet of graphite, has attracted tremendous interest owing to its novel properties including high intrinsic mobility, optical transparency and flexibility. However, for more diverse application of graphene devices, it is essential to tune its transport behavior by shifting Dirac Point (DP) of graphene. So, in the following context, we suggest a method to tune structural and electronic properties of graphene using atomic layer deposition. By atomic layer deposition of zinc oxide (ZnO) on graphene using 4-mercaptophenol as linker, we can fabricate n-doped graphene. Through ${\pi}-{\pi}$ stacking between chemically inert graphene and 4-mercaptophenol, conformal deposition of ZnO on graphene was enabled. The electron mobility of graphene TFT increased more than 3 times without considerably decreasing the hole mobility, compared to the pristine graphene. Also, it has high air stability. This ZnO doping method by atomic layer deposition can be applicable to large scale array of CVD graphene TFT.

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Linker Scanning Analysis of the BPV-1 Upstream Regulatory Region

  • Kim, Hee-Dai;Rho, Jae-Rang;Choe, Joon-Ho
    • BMB Reports
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    • v.28 no.4
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    • pp.368-373
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    • 1995
  • The upstream regulatory region (URR) of bovine papillomavirus type 1 (BPV) contains promoters and a conditional transcriptional enhancer that is trans-activated by the viral E2 protein. After deleting the 5' and 3' ends of BPV URR, BamHI linkers were inserted into several positions of BPV URR without causing an addition or a deletion of URR sequences. Most linker scanning mutations did not show any effects on the transcription of P7940 and P89 promoters in BPV URR. However, several mutants showed reduced transcriptional activities. Based on our results we found that the AP-2 and Sp1 binding sites were important for basal level transcription of BPV URR in the absence of the E2 protein and that the CTF/NF-1 site is dispensable for E2 transactivation of BPV URR transcription.

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유전독성 물질의 평가방법과 그 기작에 관한 연구

  • 이형호;주재훈;이정섭;박상대
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.04a
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    • pp.316-316
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    • 1994
  • 자외선 등에 의한 DNA 합성억제의 회복과정에서의 기작을 규명하기 위하여 자외선에 의하여 억제되었던 DNA 합성이 새로운 replication origin을 사용하는 지를 DNA 복제가 일어나는 장소로 알려진 nuclear matrix와 연관지어서 살펴 보았다. 자외선 조사후 새로 합성된 DNA 분자들의 크기는 시간이 경과하여도 대조군의 DNA 분자들의 크기보다 작았으나 그 성장 양상은 차이가 얼었고, 자외선이 조사된 세포에서 parental DNA의 부가적인 결합이 DNA 합성률의 회복에 필요함을 알 수 있었다. 또한 자외선 상해의 회복과정에서 생기는 알카리 민감성 부위는 RNA linker에 의해 생겨남을 알 수 있었다. 이상의 결과들을 종합하여 보면, 자외선에 의해 pyrimidine dimer가 생기면 첫째로 절제회복에 의해 제거되어지지만, 남아 있는 pyrimidine dimel에 의해서 DNA 복제억제는 여전히 억제되어 있다. DNA 복제억제의 회복은 새로운 복제원점이 활성화되어 nuclear matrix에 결합하여 새로운 DNA 합성이 시작됨으로써 이루어진다. 이때 RNA linker는 복제진행시 DNA 상의 gap으로 생긴 tyopological strain을 제거하는데 이용되어진다.

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Synthesis of Bis(pyronyl)acrylic Acid Ester Derivatives (Bis(pyronyl)acrylic Acid Ester 유도체의 합성)

  • Nam, Seung-Ok;Kim, Dong-Han;Lee, Yong-Sup
    • YAKHAK HOEJI
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    • v.53 no.2
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    • pp.89-92
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    • 2009
  • Dicaffeoyltartaric acid has a structural feature consisting of two caffeic acid units separated by tartaric acid linker and has been found to be a potent inhibitor of HIV-1 integrase and an antioxidant. In this study, bis(pyronyl)acrylic acid esters joined through a 5-membered ring as a linker were synthesized as the analogues of dicaffeoyltartaric acid.

Transmembrane Adaptor Proteins Positively Regulating the Activation of Lymphocytes

  • Park, In-Young;Yun, Yung-Dae
    • IMMUNE NETWORK
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    • v.9 no.2
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    • pp.53-57
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    • 2009
  • Engagement of the immunoreceptors initiates signaling cascades resulting in lymphocyte activation and differentiation to effector cells, which are essential for the elimination of pathogens from the body. For the transduction of these immunoreceptor-mediated signals, several linker proteins termed transmembrane adaptor proteins (TRAPs) were shown to be required. TRAPs serve as platforms for the assembly and membrane targeting of the specific signaling proteins. Among seven TRAPs identified so far, LAT and LIME were shown to act as a positive regulator in TCR-mediated signaling pathways. In this review, we will discuss the functions of LAT and LIME in modulating T cell development, activation and differentiation.

Development of Wireless A/V Linker for language study system (어학시스템용 무선 A/V Linker 개발)

  • Park, Cha-Hun
    • Proceedings of the KAIS Fall Conference
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    • 2008.11a
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    • pp.181-183
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    • 2008
  • 지금까지 영상매체를 이용하는 멀티어학실습실 경우 유선을 통하여 강사와 수강생, 수강생과 수강생을 연결할 수 있었다. 그리고 연결된 상태를 변경하기 위해서는 잭을 원하는 형태로 다시 꽂아 연결하거나 많은 선이 연결되는 스위치 박스를 이용했다. 하지만 이와 같은 방법은 신속하게 변경해야 하거나, 접촉 불량과 같은 문제로 고장이 발생하여 사용에 많은 불편했다. 따라서, 무선으로 연결할 수 있는 방법이 개발된다면, 이와 같은 문제를 해결할 수 있을 뿐만 아니라 다양한 부분으로 응용이 가능하다. 하지만 단순히 무선화 시킬 경우 기존의 무선 주파수 대역을 사용하거나 불필요한 잡음이 유입되는 문제점을 해결해야 한다. 본 논문에서는 이를 해결하기 위해 고주파 대역을 사용하고, 이를 제어하기 위하 수단으로 다양하게 개발되어 검증된 지그비와 블루투스 방식의 통신 기술을 이용해서 시스템을 개발하였다.

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Design, Synthesis and Anticonvulsive Activities of Potential Prodrugs Linked by Two-carbon Chain

  • Zhao, Long-Xuan;Moon, Yoon-Soo;Basnet, Ar-Jun;Park, Jae-Gyu;Kim, Eun-kyung;Kim, Dae-Ok;Jeong, Tae-Cheon;Jahng, Yurng-Dong;Choi, Jong-Won;Lee, Eung-Seok
    • Archives of Pharmacal Research
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    • v.26 no.10
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    • pp.785-795
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    • 2003
  • For the development of new anticonvulsive agents, GABAmimetics such as nipecotic acid, isonipecotic acid, ${\gamma}-aminobutyric$ acid (GABA), ${\gamma}-vinyl$ GABA (vigabatrin) and valproic acid were covalently coupled through an ester bond by a two-carbon linker chain as potential prodrugs and evaluated for their anticonvulsive activities.