滋陰丹이 皮膚의 老化에 미치는 影響

박성규,김수남,이종찬,김한성,김연준,이병곤,장이섭 대한본초학회 2004 大韓本草學會誌 Vol.19 No.1

Objectives: Jaeum-Dan (JED) I and II are new formulas composed with oriental herbs. We investigated the anti-aging effects on skin with water extracts of JED 1 , JED II, JJZD IIJ and each Bupleuri Radix, Lonicerae Caulis, Coicis Semen, Armeniacae Amarum Semen, Plantaginis Herba. Methods: We measured various effects related to skin such as the proliferation of keratinocytes, the inhibition of reactive oxygen species (ROS) generation, 5a-reductase activity, the gap junctional intercellular communication, the amount of melanin and the synthesis of MMP-1 and type I procollagen. Results: The proliferation of keratinocytes were increased in JED I , 11, ID and water extracts of Bupleun Radix, Plantaginis Herba. The production of ROS were decreased in JED I , II, IJl and water extract of Bupleun Radix. 5a-reductase activity were decreased in JED I , II, lII and water extract of Lonicerae Caulis. Gap junctional intercellular communcation were increased to normal level in water extract of Coicis Semen. The amount of melanin were decreased in JED I , II, IU and water extract of Armeniacae Amarum Semen, Plantaginis Herba. The synthesis of MMP-1 and type I procollagen were positive in JED I , II, ID and water extract of Plantaginis Herba. Conclusions: The results of our study indicate that each 5 herbs have anti-aging effects and the complex of JED I with rl were best in anti-aging effects on skin.

Time scale of dynamic heterogeneity in model ionic liquids and its relation to static length scale and charge distribution

Park, Sang-Won,Kim, Soree,Jung, YounJoon The Royal Society of Chemistry 2015 Physical chemistry chemical physics Vol.17 No.43

<P>We study how dynamic heterogeneity in ionic liquids is affected by the length scale of structural relaxation and the ionic charge distribution by the molecular dynamics simulations performed on two differently charged models of ionic liquid and their uncharged counterpart. In one model of ionic liquid, the charge distribution in the cation is asymmetric, and in the other it is symmetric, while their neutral counterpart has no charge with the ions. It is found that all the models display heterogeneous dynamics, exhibiting subdiffusive dynamics and a nonexponential decay of structural relaxation. We investigate the lifetime of dynamic heterogeneity, <I>τ</I><SUB>dh</SUB>, in these systems by calculating the three-time correlation functions to find that <I>τ</I><SUB>dh</SUB> has in general a power-law behavior with respect to the structural relaxation time, <I>τ</I><SUB><I>α</I></SUB>, <I>i.e.</I>, <IMG SRC='http://www.rsc.org/ej/CP/2015/c5cp03390j/c5cp03390j-t2.gif'>. Although the dynamics of the asymmetric-charge model is seemingly more heterogeneous than that of the symmetric-charge model, the exponent is found to be similar, <I>ζ</I><SUB>dh</SUB>≈ 1.2, for all the models studied in this work. The same scaling relation is found regardless of interactions, <I>i.e.</I>, with or without Coulomb interaction, and it holds even when the length scale of structural relaxation is long enough to become the Fickian diffusion. This fact indicates that <I>τ</I><SUB>dh</SUB> is a distinctive time scale from <I>τ</I><SUB><I>α</I></SUB>, and the dynamic heterogeneity is mainly affected by the short-range interaction and the molecular structure.</P> <P>Graphic Abstract</P><P>We find a general power-law behavior: <IMG SRC='http://www.rsc.org/ej/CP/2015/c5cp03390j/c5cp03390j-t1.gif'>, where <I>ζ</I><SUB>dh</SUB>≈ 1.2 for all the ionic liquid models, regardless of charges and the length scale of structural relaxation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5cp03390j'> </P>

Excitation-energy dependence of solvation dynamics in room-temperature ionic liquids

Kim, Daekeon,Park, Sang-Won,Shim, Youngseon,Kim, Hyung J.,Jung, YounJoon American Institute of Physics 2016 The Journal of chemical physics Vol.145 No.4

Spontaneous gastric perforation caused by internal gastric bleeding in prematurity

Euitae KIM,Younjoon PARK,Injun YANG 대한외과학회 2019 대한외과학회 학술대회 초록집 Vol.2019 No.10

Heterogeneous dynamics and its length scale in simple ionic liquid models: a computational study

Kim, Soree,Park, Sang-Won,Jung, YounJoon The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.9

<P>We numerically investigate the dynamic heterogeneity and its length scale found in coarse-grained ionic liquid model systems. In our ionic liquid model systems, cations are modeled as dimers with a positive charge, while anions are modeled as monomers with a negative charge, respectively. To study the effect of the charge distributions on the cations, two ionic liquid models with different charge distributions are used and the model with a neutral charge is also considered as a counterpart. To reveal the heterogeneous dynamics in the model systems, we examine spatial distributions of displacement and time distributions of exchange and persistence times. All the models show a significant increase of the dynamic heterogeneity as the temperature is lowered. The dynamic heterogeneity is quantified via the well-known four-point susceptibility, chi(4)(t), which measures the fluctuations of a time correlation function. The dynamic correlation length is calculated by fitting the dynamic structure factor, S-4(k, t), with the Ornstein-Zernike form at the time scale at which the dynamic heterogeneity reaches the maximum value. The obtained time and length scales exhibit a power law relation at the low temperatures, similar to various supercooled liquid models. In particular, the charged model systems show unusual crossover behaviors which are not observed in the uncharged model system. We ascribe the crossover behavior to the enhanced cage effect caused by charges on the particles.</P>

Computer simulation study of differential capacitance and charging mechanism in graphene supercapacitors: Effects of cyano-group in ionic liquids

Jo, Sungsik,Park, Sang-Won,Noh, Chanwoo,Jung, YounJoon Elsevier 2018 ELECTROCHIMICA ACTA Vol.284 No.-

<P><B>Abstract</B></P> <P>Molecular dynamics simulation is employed to study graphene supercapacitors. Four different ionic liquids are considered as an electrolyte, each of which is combination of the same cation 1-ethyl-3-methylimidazolium([emim]<SUP>+</SUP>), and different, cyano-containing anions, thiocyanate ([SCN]<SUP>–</SUP>), dicyanamide ([N(CN)<SUB>2</SUB>]<SUP>–</SUP>), tricyanomethanide ([C(CN)<SUB>3</SUB>]<SUP>–</SUP>), and tetracyanoborate ([B(CN)<SUB>4</SUB>]<SUP>–</SUP>), respectively. In particular we investigate how electric double layer structure and electrical properties are affected by the structure of cyano containing anions. Cations and anions make alternating structure near charged electrode. Differential capacitances in four ionic liquids are found to have a maximum value at negative potential. The maximum capacitances are comparable to each other, but the corresponding potential shifts to the negative side as more cyano groups are attached to the anion. Starting from the interfacial layer, the effects of the further ionic layers on differential capacitance are systematically investigated. Comparing charges of the electrode and those of ionic layers, we find that differential capacitance behavior mainly stems from the ion exchange between electric double layer and bulk region. The ion exchange behaviors are decomposed into cation and anion contributions. The differential charging mechanisms of the system are strongly dependent on the electric potential. The maximum capacitances are consequence of rapid desorption of respective anions.</P>

Effects of Alkyl Chain Length on Interfacial Structure and Differential Capacitance in Graphene Supercapacitors: A Molecular Dynamics Simulation Study

Jo, Sungsik,Park, Sang-Won,Shim, Youngseon,Jung, YounJoon Elsevier 2017 ELECTROCHIMICA ACTA Vol.247 No.-

<P><B>Abstract</B></P> <P>Supercapacitors with graphene electrodes are studied via molecular dynamics simulation. As an electrolyte, we consider three different room-temperature ionic liquids (RTILs), each of which is made up of the same anion BF<SUB>4</SUB> <SUP>−</SUP>, and different cations, 1-C<SUB>n</SUB>(n=2,4,6)-3-methylimidazolium, respectively. We investigate how the alkyl chain length of the cation affects their interfacial structure and electrical properties for electric double layer capacitors. As a whole, cations and anions make layering structures between two parallel electrodes. Cations in the nearest layer orient predominantly in parallel to the electrode. Imidazolium rings of cations form π-stacking with graphene, then the alkyl chains of cations align parallel to the electrode. Differential capacitances in three RTILs are found to decrease with an increase of the magnitude of electrode potentials. The ion size and orientation affect both structure and capacitance behavior. The parallel orientations of cations become stronger with an increase of the alkyl chain length for the considered RTILs. The differential capacitance tends to decrease with raising the alkyl chain length over a wide range of the electrode potential. This is ascribed to a steric effect caused by larger cation size. It is also found that anodic capacitance is higher than cathodic one due to a higher screening efficiency by small anions, and an asymmetry in the peak of capacitance biased to the cathodic side becomes weaker as the alkyl chain length increases. Comparing electrode charge with ion numbers near the electrodes, with respect to their changes in response to the electrode potential, we find that the interfacial layer of the electrolyte mainly governs capacitive behavior of the systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The structure and electrical properties of the supercapacitors consisting of imidazolium-based ionic liquids are studied via molecular dynamics simulation. </LI> <LI> A longer alkyl chain of cations results in an enhanced π-stacking with the graphene electrode, but a lower differential capacitance. </LI> <LI> Ionic layers are defined from the ion number density distribution as a function of electrode charge. </LI> <LI> differential ion capacity shows a good correlation with the differential capacitance, indicating the importance of the interfacial layer of the electrolyte. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

인공지능 스피커의 시각 피드백 유형에 따른 사용자 경험 연구: 인지욕구와 멀티태스킹 조절 효과를 중심으로

박소진(Sojin Park),이연준(Younjoon Lee) 한국디자인학회 2020 디자인학연구 Vol.33 No.2

First Experience of Junior Surgeon with Laparoscopic Totally Extraperitoneal Herniorrhaphy: Comparison with Experienced Surgeon

Dong-Wook Kim,Younjoon Park 대한외과학회 2020 대한외과학회 학술대회 초록집 Vol.2020 No.11

Graphene Oxide Supercapacitors: A Computer Simulation Study

DeYoung, Andrew D.,Park, Sang-Won,Dhumal, Nilesh R.,Shim, Youngseon,Jung, YounJoon,Kim, Hyung J. American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.32

<P>Supercapacitors with graphene oxide (GO) electrodes in a parallel plate configuration are studied with molecular dynamics (MD) simulations. The full range of electrode oxidation from 0% (pure graphene) to 100% (fully oxidized GO) is investigated by decorating the graphene surface with hydroxyl groups. The ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI<SUP>+</SUP>BF<SUB>4</SUB><SUP>−</SUP>) is examined as an electrolyte. Capacitance tends to decrease with increasing electrode oxidation, in agreement with several recent measurements. This trend is attributed to the decreasing reorganization ability of ions near the electrode and a widening gap in the double layer structures as the density of hydroxyl groups on the electrode surface increases.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-32/jp5072583/production/images/medium/jp-2014-072583_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5072583'>ACS Electronic Supporting Info</A></P>