http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Jooyeon Hong,이제욱,함시현 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.2
The structural and energetic preferences of thiacalix[4]biscrown-5 with and without alkali metal ions (Na+, K+, Rb+and Cs+) have been theoretically investigated for the first time using molecular dynamic (MD) simulations and density functional theory (MPWB1K/6-31G(d)//B3LYP/6-31G(d)) methods. The formation of the metal ion complex by the host is mainly driven by the electrostatic attraction between crown-5 oxygens and a cation together with the minor contribution of the cation-π interaction between two facing phenyl rings around the cation. The computed binding energies and the atomic charge distribution analysis for the metal binding complexes indicate the selectivity toward a potassium ion. The theoretical results herein explain the experimentally observed extractability order by this host towards various alkali metal ions. The physical nature and the driving forces for cation recognition by this host are discussed in detail.
Hong Jooyeon 한국식물학회 2020 Journal of Plant Biology Vol.63 No.5
Upward Curly Leaf 1 (UCL1) is an Arabidopsis thaliana E3 ligase that targets the Curly Leaf (CLF) SET-domain polycomb-group (PcG) protein for degradation via the ubiquitin-26S proteasome system. UCL1 is a paternally-expressed imprinted gene in the endosperm. To precisely locate the promoter elements required for UCL1 imprinting pattern, various gene constructs were created in which the imprinting control region (ICR), endosperm-specific expression (ENSE) element, and/or the linker sequence were altered. By fusing these constructs with a GUS reporter gene, GUS expression patterns were monitored after reciprocal crosses with wild-type Columbia-0 allowing the determination of parent-of-origin expression. Analysis of publicly-available data on the UCL1 promoter region facilitated the search for allele-specific DNA and H3K27 methylation patterns. Overall, three promoter elements are required for maternal repression of UCL1; the ICR sequence located from − 2.5 to − 2.4 kb upstream of the translation start site, a differentially methylated region 2 (DMR2) that overlaps the short ATLINE1-1 transposable element in the linker region, and a minimal 271 bp ENSE element. In addition, DNA methylation patterns in the DMR2 contribute to the repression of the maternal UCL1 allele. Our findings would help to understand how parent-of-origin epigenetic patterns are created and maintained in the endosperm.
Computational Study on the Conformational Characteristics of Calix[4]pyrrole Derivatives
Jooyeon Hong,Minkyung Son,함시현 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.2
The comparative study of three calix[4]heterocycles (calix[4]pyrrole, calix[4]furan, and calix[4]thiophene) has been theoretically performed by using high-level density functional theory (DFT) at the MPWB1K/6-311G**//B3LYP/6- 311G** level. The effect of different hetero-atoms (nitrogen, oxygen, and sulfur) placed in the heterocycles on the conformational flexibility, thermodynamic stability order, cavity sizes, charge distributions, and binding propensities are examined. The thermodynamic stability differences between the conformers are found to be much greater in calix[4]pyrrole compared to those in calix[4]furan and calix[4]thiophene. Relatively larger NH group and higher dipole of a pyrrole ring in calix[4]pyrrole contribute to the higher energy barrier for the conformational conversions and relatively rigid potential energy surface compared to the case of calix[4]furan and calix[4]thiophene. The computational results herein provide theoretical understanding of the conformational flexibility and the thermodynamic nature which can be applied to understand the complexation behavior of the three calix[4]heterocycles.
Elucidating the Molecular Origin of Hydrolysis Energy of Pyrophosphate in Water
Hong, Jooyeon,Yoshida, Norio,Chong, Song-Ho,Lee, Chewook,Ham, Sihyun,Hirata, Fumio American Chemical Society 2012 Journal of chemical theory and computation Vol.8 No.7
<P>The molecular origin of the energy produced by the ATP hydrolysis has been one of the long-standing fundamental issues. A classical view is that the negative hydrolysis free energy of ATP originates from intramolecular effects connected with the backbone P–O bond, so called “high-energy bond”. On the other hand, it has also been recognized that solvation effects are essential in determining the hydrolysis free energy. Here, using the 3D-RISM-SCF (three-dimensional reference interaction site model self-consistent field) theory that integrates the <I>ab initio</I> quantum chemistry method and the statistical mechanical theory of liquids, we investigate the molecular origin of hydrolysis free energy of pyrophosphate, an ATP analogue, in water. We demonstrate that our theory quantitatively reproduces the experimental results without the use of empirical parameters. We clarify the crucial role of water in converting the hydrolysis free energy in the gas phase determined solely by intramolecular effects, which ranges from endothermic, thermoneutral, to highly exothermic depending on the charged state of pyrophosphate, into moderately exothermic in the aqueous phase irrespective of the charged state as observed in experimental data. We elucidate that this is brought about by different natures of solute–water interactions depending on the charged state of solute species: the hydration free energy of low-charged state is mainly subjected to short-range hydrogen-bonds, while that of high-charged state is dominated by long-range electrostatic interactions. We thus provide unambiguous evidence on the critical role of water in determining the ATP hydrolysis free energy.</P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ct300099e'>ACS Electronic Supporting Info</A></P>
모션 블러된 이미지로부터 블러 파라미터를 추출하는 기법에 대한 연구
양홍택(Hong-Taek Yang),황주연(Jooyeon Hwang),백두원(Doowon Paik) 한국HCI학회 2008 한국HCI학회 학술대회 Vol.2008 No.2
촬영 순간 카메라와 촬영대상간의 상대적인 움직임에 의해 촬영된 이미지에는 움직인 방향으로 모션 블러가 발생할 수 있다. 의도 되지 않은 블러 효과는 이미지 품질에 손상을 주므로 블러 효과에 의해 손상된 이미지를 복원할 필요가 있다. 블러 효과에 의해 손상된 이미지의 복원을 위해서는 블러 효과를 발생시키는 블러의 성분을 정확히 알아내어야 한다. 본 논문에서는 모션 블러가 발생된 이미지로부터 모션 블러의 성분을 추출하는 새로운 방법을 제안하고 실험을 통해 제안된 방법의 성능을 검증하였다. 실험 결과는 제안된 방법이 오브젝트의 크기와 블러의 크기에 상관없이 블러의 크기를 정확히 추출함을 보여 주었다. Motion blurs are caused by relative motion between the camera and the scene. The blurred image needs to be restored because undesired blur effect degrades the quality of the image. In this paper, we propose a new method for the identification of blur parameters. Experiment shows that the proposed method identifies blur extent regardless of the size of the blur and the object in the original image.
Park, Jooyeon,Kim, Bokyoung,Han, Jin,Oh, Jaewon,Park, Subeom,Ryu, Seungmi,Jung, Subin,Shin, Jung-Youn,Lee, Beom Seob,Hong, Byung Hee,Choi, Donghoon,Kim, Byung-Soo American Chemical Society 2015 ACS NANO Vol.9 No.5
<P>Mesenchymal stem cell (MSC) implantation has emerged as a potential therapy for myocardial infarction (MI). However, the poor survival of MSCs implanted to treat MI has significantly limited the therapeutic efficacy of this approach. This poor survival is primarily due to reactive oxygen species (ROS) generated in the ischemic myocardium after the restoration of blood flow. ROS primarily causes the death of implanted MSCs by inhibiting the adhesion of the MSCs to extracellular matrices at the lesion site (<I>i.e.</I>, anoikis). In this study, we proposed the use of graphene oxide (GO) flakes to protect the implanted MSCs from ROS-mediated death and thereby improve the therapeutic efficacy of the MSCs. GO can adsorb extracellular matrix (ECM) proteins. The survival of MSCs, which had adhered to ECM protein-adsorbed GO flakes and were subsequently exposed to ROS <I>in vitro</I> or implanted into the ischemia-damaged and reperfused myocardium, significantly exceeded that of unmodified MSCs. Furthermore, the MSC engraftment improved by the adhesion of MSCs to GO flakes prior to implantation enhanced the paracrine secretion from the MSCs following MSC implantation, which in turn promoted cardiac tissue repair and cardiac function restoration. This study demonstrates that GO can effectively improve the engraftment and therapeutic efficacy of MSCs used to repair the injury of ROS-abundant ischemia and reperfusion by protecting implanted cells from anoikis.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-5/nn507149w/production/images/medium/nn-2014-07149w_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn507149w'>ACS Electronic Supporting Info</A></P>