Desumoylation of homeodomain-interacting protein kinase 2 (HIPK2) through the cytoplasmic-nuclear shuttling of the SUMO-specific protease SENP1

Kim, Young Ho,Sung, Ki Sa,Lee, Sook-Jeong,Kim, Yong-Ou,Choi, Cheol Yong,Kim, Yongsok Elsevier 2005 FEBS letters Vol.579 No.27

<P><B>Abstract</B></P><P>The modification of homeodomain-interacting protein kinase 2 (HIPK2) by small ubiquitin-like modifier 1 (SUMO-1) plays an important role in its targeting into the promyelocytic leukemia body, as well as in its differential interaction with binding partner, but the desumoylation of HIPK2 by SUMO-specific proteases is largely unknown. In this study, we show that HIPK2 is a desumoylation target for the SUMO-specific protease SENP1 that shuttles between the cytoplasm and the nucleus. Mutation analyses reveal that SENP1 contains the nuclear export sequence (NES) within the extreme carboxyl-terminal region, and SENP1 is exported to the cytoplasm in a NES-dependent manner. Sumoylated HIPK2 are deconjugated by SENP1 both in vitro and in cultured cells, and the desumoylation is enhanced either by the forced translocation of SENP1 into the nucleus or by the SENP1 NES mutant. Concomitantly, desumoylation induces dissociation of HIPK2 from nuclear bodies. These results demonstrate that HIPK2 is a target for SENP1 desumoylation, and suggest that the desumoylation of HIPK2 may be regulated by the cytoplasmic-nuclear shuttling of SENP1.</P>

Highly Efficient Vacuum-Processed Organic Solar Cells Containing Thieno[3,2-<i>b</i>]thiophene-thiazole

Kim, Jihun,Shim, Hyun-Sub,Lee, Horim,Choi, Min-Soo,Kim, Jang-Joo,Seo, Yongsok American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.22

<P>Two novel electron-donor molecules based on donor−π-conjugated linker–acceptor structure with compact packing and intramolecular charge-transfer characteristics were synthesized for the preparation of efficient organic solar cells. The donor molecules featuring an electron-rich triphenyl amine as the electron-donor unit, dicyanovinylene as the acceptor unit, and π-conjugated linkers of thienothiophene, thiophene, and thiazole units were synthesized. The π-conjugated linkers were carefully designed to have a planar structure, an efficient conjugation length, and appropriate energy levels for a compact packing in the solid state. The vacuum-processed solar cells fabricated using the donor molecules of DTTh and DTTz exhibited average power-conversion efficiencies (PCEs) of 5.4 and 6.2% (the highest PCE obtained was 6.37%) under AM 1.5G illumination with an intensity of 100 mW cm<SUP>–2</SUP>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-22/jp5017467/production/images/medium/jp-2014-017467_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5017467'>ACS Electronic Supporting Info</A></P>

Comparative Perspectives on the American Juvenile Justice Systems

Kim, Yongsok,Chun, Yongtae 한국교정복지학회 2014 교정복지연구 Vol.- No.34

최근 점차 많은 청소년들이 폭력적인 성향의 범죄를 저지르고 있다는 대중들 의 우려가 전 세계적으로 커지고 있다. 그러한 우려 속에 일부 국가들, 특히 미 국에서는 범행을 저지른 청소년의 징벌에 중심을 두는 사법적 대응이 시행되고 있다. 징벌에 초점을 둔 형사사법적 대응과는 다른 관점에서, 이 연구에서는 청 소년의 인권에 관한 세계적인 논의와 추세, 청소년 범죄에 대한 다른 여러 국가 들의 대응을 살펴보았다. 이러한 논의에는 한국, 일본, 그리고 유럽 소재 국가들 의 청소년 대상 사법현실에 대한 조명이 포함되었다. 또한, 이전보다 응보적이고 징벌적인 사법대응이 실행되고 있는 현재 미국의 청소년 대상 사법체계의 변천 과정을 살펴보았다. 한편, 미국 청소년 대상 사법현실에 중대한 영향을 미칠 수 있는 두 가지 미국 연방대법원 판결에 대한 조명을 통해 미국의 청소년 범죄에 대한 대처방향이 종전의 징벌적 경향에서 청소년의 성인과 다른 특징을 고려하 고 청소년의 복지를 고려하는 방향으로 전환할 수 있는가를 살펴보았다. 아울러 청소년 대상 사법적 대응에 관한 세계적인 추세를 참조하였던 이러한 두 판결의 전문을 살펴봄으로써, 국제적으로 다양한 분야에 큰 영향력을 미치는 미국이 청 소년의 인권과 복지에 관한 범세계적 논의에 보다 전향적으로 참여할 수 있는 계기가 될 수 있는지도 살펴보았다. There have been public concerns that more and more juveniles have been committing more violent crimes than the past in many countries. Such concerns have led some countries, especially the United States, to implement a more punitive justice approach. Aside from the current juvenile justice approach, this article examines the international views of human rights with regard to juveniles and the international trend in juvenile justice systems by looking at the situations in other countries including South Korea, Japan, and some of European countries. When investigating U. S. juvenile justice practices, some juveniles in the U. S. have been transferred to adult criminal courts, and it has been much likely that they get mandatory sentencing, the juvenile death penalty and life imprisonment Supreme Court decision of Roper v. Simmons (2005), juveniles under the age of 18 at the time of offense can avoid the death penalty. In another historic Supreme Court decision of Graham v. Florida (2010), the Court held that a juvenile, who is not convicted of homicide, will not be given a life sentence without the possibility of parole. In both cases, the Court has emphasized U. S. states' sentencing practices and considered international trends. Finally, it is discussed how the U. S. may be shifting the goals of the juvenile justice system from one of mere punishment to one that considers the rights and welfare of juveniles.

Resonant Multiple Light Scattering for Photon Harvest Enhancement in Dye-Sensitized Solar Cells

Jihun Kim,Horim Lee,Dong Young Kim,Yongsok Seo 한국고분자학회 2014 한국고분자학회 학술대회 연구논문 초록집 Vol.2014 No.10

Efficient Vacuum-Deposited Tandem Organic Solar Cells with Fill Factors Higher Than Single-Junction Subcells

Shim, Hyun-Sub,Lin, Francis,Kim, Jihun,Sim, Bomi,Kim, Tae-Min,Moon, Chang-Ki,Wang, Chun-Kai,Seo, Yongsok,Wong, Ken-Tsung,Kim, Jang-Joo Wiley Blackwell (John Wiley Sons) 2015 ADVANCED ENERGY MATERIALS Vol.5 No.13

Enhanced X-ray Shielding Ability of Polymer–Nonleaded Metal Composites by Multilayer Structuring

Kim, Yoonkwan,Park, Seongeun,Seo, Yongsok American Chemical Society 2015 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.54 No.22

<P>Polymer–nonleaded metal (tungsten, Sendust) composites were prepared to study the effects of multilayer structure on X-ray shielding ability. Though the metals were nonleaded, the metal contents were low, and the composite films were thin, the composite films showed favorable X-ray shielding ability due to the uniform dispersion of metal particles in the polymer matrix and the flake alignment (Sendust). This means that multi- layered particles can effectively absorb the penetrating photons and they fill the pin holes in the composite. More uniformly aligned Sendust shows better shielding effect than randomly oriented Sendust. The lamination order of tungsten film and Sendust composite film affects the final performance of the laminated composites. This work demonstrates that nonleaded metal–polymer composite can be applied for X-ray shielding as a reliable substitute material for lead.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/iecred/2015/iecred.2015.54.issue-22/acs.iecr.5b00425/production/images/medium/ie-2015-00425x_0009.gif'></P>

Fracture Mechanism Change at a Heterogeneous Polymer-Polymer Interface Reinforced with in Situ Graft Copolymers

Kim, Hoyeon,Kawaguchi, Daisuke,Tanaka, Keiji,Seo, Yongsok American Chemical Society 2018 Langmuir Vol.34 No.37

<P>Dynamic secondary-ion mass spectroscopy (DSIMS) was used to investigate the change in the failure mechanism at a heterogeneous polymer-polymer interface (polystyrene (PS)/polyamide (nylon 6, Ny6)) reinforced with in situ graft copolymers produced by the reaction between Ny6 molecules and poly(styrene-<I>co</I>-maleic anhydride) at the interface. The variation in fracture toughness with bonding time and temperature has been explained by two different failure mechanisms: adhesive failure at the interface for short bonding times and when the bonding temperature is low and cohesive failure between chains at the interface and bulk PS for longer bonding times and when the bonding temperature is high. DSIMS results provide the direct experimental evidence that the nonreactive molecules (PS) diffuse away from the high-potential interface, which induces the cohesive failure in the bulk of the nonreactive molecules (PS) after long annealing times. The change in the adhesion strength with temperature could also cause a change in the failure mechanism. Common features of the fracture mechanisms at heterogeneous interfaces reinforced by the in situ graft copolymers are outlined, which are independent of the polymer crystallinity.</P> [FIG OMISSION]</BR>

Synthesis of semiconducting poly(diphenylamine) particles and analysis of their electrorheological properties

Kim, Min Hwan,Bae, Dong Hun,Choi, Hyoung Jin,Seo, Yongsok Elsevier 2017 Polymer Vol.119 No.-

<P><B>Abstract</B></P> <P>Poly(diphenylamine) (PDPA) particles were synthesized as a novel semiconducting electro-responsive electrorheological (ER) material by a chemical oxidative polymerization process and their ER characteristics were investigated at various electric fields. Surface morphology of these <I>N</I>-aryl-substituted polyaniline-derived PDPA particles was examined by scanning electron microscopy and their chemical structure and thermal properties were confirmed by Fourier-transform infrared spectroscopy and thermogravimetric analysis, respectively. Their susceptibility to electric fields and the chain formation of dispersed particles were observed directly using optical microscopy. Rheological analysis of the PDPA-based ER fluid was performed using a combination of steady shear and oscillation tests in a Couette-type rotational rheometer with a high-voltage power supply. The measurements were performed in controlled shear stress and shear rate modes under the varied electric field strengths. The Cho–Choi–Jhon model was found to determine the stress behavior more clearly. Dielectric analysis provided additional information about the electrical polarization properties and thus also the ER performance of the PDPA-based ER fluid.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Semiconducting poly(diphenylamine) (PDPA) particles were synthesized by chemical oxidation. </LI> <LI> PDPA particles show typical electrorheological (ER) property examined using a rotational rheometer. </LI> <LI> PDPA particles are directly applied into ER fluid without dedoping process. </LI> <LI> Dielectric analysis was proceeded to confirm electrical polarization of PDPA particles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Coating of magnetic particle with polystyrene and its magnetorheological characterization

Kim, Yoon Hee,Park, Bong Jun,Choi, Hyoung Jin,Seo, Yongsok WILEY-VCH Verlag 2007 Physica status solidi. PSS. A, Applications and ma Vol.204 No.12

<P>Magnetic composite particles were prepared via dispersion polymerization of styrene in the presence of γ-Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles. The fabricated magnetic composite nanoparticles were dispersed into non-magnetic suspending media to be adopted for magnetorheological (MR) fluid, whose rheological properties can be drastically changed in the external magnetic field. The MR efficiency of γ-Fe<SUB>2</SUB>O<SUB>3</SUB>/polystyrene composite based fluid was examined by a rotational rheometer equipped with a magnetic field supplier. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

Pickering-Emulsion-Polymerized Polystyrene/Fe₂O₃ Composite Particles and Their Magnetoresponsive Characteristics

Kim, Young Jae,Liu, Ying Dan,Seo, Yongsok,Choi, Hyoung Jin American Chemical Society 2013 Langmuir Vol.29 No.16

<P>Core–shell-structured magnetic polystyrene (PS)/inorganic particles were fabricated by Pickering emulsion polymerization using nanosized Fe<SUB>2</SUB>O<SUB>3</SUB> particles as a solid stabilizer. Scanning electron microscopy and transmission electron microscopy confirmed the synthesized PS/Fe<SUB>2</SUB>O<SUB>3</SUB> particles to be comprised of a PS surface coated with Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles. The chemical structure of the composite nanospheres was characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The thermal properties of composite nanospheres and corresponding pure polymer were examined by thermogravimetric analysis. The rheological properties of the core–shell-structured magnetic PS/inorganic particles dispersed in silicone oil were investigated under an external magnetic field strength using a rotational rheometer. The particles with extremely lower density than common magnetic particles exhibited solid-like magnetorheological phase characteristics, and the flow curves were fitted to the Cho–Choi–Jhon model of the rheological equation of state.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2013/langd5.2013.29.issue-16/la400523w/production/images/medium/la-2013-00523w_0011.gif'></P>