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Search Results: 1 - 10 of 10426 matches for " Hyun-Chul Park "
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Effect of Hoechunyangkyeok-San Extract on Melanogenesis  [PDF]
Mi Jin Kim, Taek Kyu Jung, Hyun-Chul Park, Kyung-Sup Yoon
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2016, DOI: 10.4236/jcdsa.2016.63011
Abstract: Forsythia fructus has been shown to have antioxidative, anti-inflammatory, antibacterial, anti-aging and whitening effects. Hoechunyangkyeok-san (Forsythia viridissima-prescription) is a traditional herbal medicine, which has been clinically used for treating febrile and inflammatory disorders. This work was carried out to investigate the skin whitening effects of Forsythia viridissima-prescription extract (a hydrolyzed extract of Hoechunyangkyeok-san: SID White HYC) on skin. The effects of SID White HYC were assessed the melanin contents in B161 melanoma cells and the pigmented equivalent with HMB45 and Fontana Masson staining in 3D skin model. Then, we examined the expression of major pigment enzymes regulating melanin synthesis and melanosome transport related proteins in B16F1 cells. SID White HYC significantly inhibited the melanin synthesis (56.7% and 30.6% inhibition at 100 μg/mL, intracellular and secreted, respectively) in B16F1 cells and 3D skin model. In addition, western blotting analysis showed that SID White HYC reduced the expression of melanin synthesis and melanosome transport related proteins in B16F1 cells. In clinical trials, the cream containing 0.05% SID White HYC showed skin depigmentation effect without any irritation. These results suggest that SID White HYC may be useful inhibition of melanogenesis and melanosome transport. Therefore, SID White HYC may have potential as a skin-whitening ingredient in cosmetics.
Analysis of Context Dependence in Social Interaction Networks of a Massively Multiplayer Online Role-Playing Game
Seokshin Son, Ah Reum Kang, Hyun-chul Kim, Taekyoung Kwon, Juyong Park, Huy Kang Kim
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033918
Abstract: Rapid advances in modern computing and information technology have enabled millions of people to interact online via various social network and gaming services. The widespread adoption of such online services have made possible analysis of large-scale archival data containing detailed human interactions, presenting a very promising opportunity to understand the rich and complex human behavior. In collaboration with a leading global provider of Massively Multiplayer Online Role-Playing Games (MMORPGs), here we present a network science-based analysis of the interplay between distinct types of user interaction networks in the virtual world. We find that their properties depend critically on the nature of the context-interdependence of the interactions, highlighting the complex and multilayered nature of human interactions, a robust understanding of which we believe may prove instrumental in the designing of more realistic future virtual arenas as well as provide novel insights to the science of collective human behavior.
Lambda(1405,1/2^-) photoproduction from the gamma p -> K^+ Lambda(1405) reaction
Seung-il Nam,Ji-Hyoung Park,Atsushi Hosaka,Hyun-Chul Kim
Physics , 2008,
Abstract: We investigate the photoproduction of Lambda(1405,1/2^-) = Lambda* off the proton target using the effective Lagrangian in the Born approximation. We observed that, depending on the choice of the K* N Lambda* coupling strength, the total cross section becomes 0.1 <~ sigma_Lambda* <~ 0.2 mu b near the threshold and starts to decrease beyond E_gamma ~ 1.6 GeV, and the angular dependence shows a mild enhancement in the forward direction. It turns out that the energy dependence of the total cross section is similar to that shown in the recent LEPS experiment. This suggests that the production mechanism of the Lambda* is dominated by the s-channel contribution.
Form factors of the nucleon in the SU(3) chiral quark-soliton model
Hyun-Chul Kim
Physics , 1996,
Abstract: The recent investigation on various form factors of the nucleon is reviewed in the framework of the SU(3) chiral quark-soliton model. The results for the electromagnetic and scalar form factors are in remarkable agreement with experimental and empirical data. The strange vector form factors are also discussed with the effect of the kaon cloud being considered. In addition to the form factors, the recent calculation of the tensor charges is presented.
Spectrophotometric Evolution of Old Stellar Systems
Hyun-chul Lee
Physics , 2001, DOI: 10.1086/322921
Abstract: Theoretical integrated spectrophotometric quantities, such as spectral line indices in the Lick system (Hbeta, Mg2, Mg b, Fe5270, Fe5335), broadband color indices (in the UBVRIHK and Washington CMT1 bandpasses), and surface brightness fluctuation magnitudes and colors, ranging from far-UV to near-IR have been consistently computed for simple stellar populations from our evolutionary population synthesis code. The age range of -4 Gyr < Delta_t < +4 Gyr is explored, where Delta_t = 0 Gyr is the currently favored mean age of inner halo Galacitc globular clusters (Galactocentric radius < 8 kpc), ~ 12Gyr. The main aim of this dissertation is to investigate the effects of post-red giant branch stars on the integrated spectrophotometric quantities after employing detailed systematic variation of horizontal-branch morphology with age and metallicity.
Hybrid exotic meson with J^{PC}=1^{-+} in AdS/QCD
Kim, Hyun-Chul;Kim, Youngman
High Energy Physics - Phenomenology , 2008, DOI: 10.1088/1126-6708/2009/01/034
Abstract: We investigate the hybrid exotic meson with $J^{PC}=1^{-+}$ within the framework of an AdS/QCD model. Introducing a holographic field dual to the operator for hybrid exotic meson, we obtain the eigen-value equation for its mass. Fixing all free parameters by QCD observables such as the $\rho$-meson mass, we predict the masses of the hybrid exotic meson. The results turn out to be $1476 \mathrm{MeV}$ for the ground state, and $2611 \mathrm{MeV}$ for the first excited one. Being compared with the existing experimental data for the $\pi_1(1400)$, which is known to be $m_{\pi_1} = 1351\pm30 \mathrm{MeV}$, the present result seems to be qualitative in agreement with it. We also predict the decay constant of $\pi_1$(1400): $F_{\pi_1}= 10.6$ MeV.
Transverse charge densities in the nucleon in nuclear matter
Yakhshiev, Ulugbek;Kim, Hyun-Chul
High Energy Physics - Phenomenology , 2013,
Abstract: We investigated the transverse charge densities in the nucleon in nuclear matter within the framework of the in-medium modified Skyrme model. The medium modification of the nucleon electromagnetic form factors are first discussed. The results show that the form factors in nuclear matter fall off faster than those in free space, as the momentum transfer increases. As a result, the charge radii of the nucleon become larger, as the nuclear matter density increases. The transverse charge densities in the nucleon indicate that the size of the nucleon tends to bulge out in nuclear matter. This salient feature of the swelling is more clearly observed in the neutron case. When the proton is transversely polarized, the transverse charge densities exhibit the distortion due to the effects of the magnetization.
Quark-gluon mixed condensate of the QCD vacuum in Holographic QCD
Kim, Hyun-Chul;Kim, Youngman
High Energy Physics - Phenomenology , 2008, DOI: 10.1088/1126-6708/2008/10/011
Abstract: We investigate the quark-gluon mixed condensate based on an AdS/QCD model. Introducing a holographic field dual to the operator for the quark-gluon mixed condensate, we obtain the corresponding classical equation of motion. Taking the mixed condensate as an additional free parameter, we show that the present scheme reproduces very well experimental data. A fixed value of the mixed condensate is in good agreement with that of the QCD sum rules.
Properties of the bound nucleons
Yakhshiev Ulugbek,Kim Hyun-Chul
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20122004005
Abstract: We present recent investigations on the properties of nucleons in nuclear matter and, in particular, nucleon electromagnetic form factors in the framework of the in-medium modified Skyrme model. Medium modifications are achieved by introducing the pion-nucleus optical potential for the pion fields in nuclear environment. In order to reproduce the bulk matter properties, the parametrization of the Skyrme term in the nuclear matter has been adjusted and the sensitivity of results to the pion-nucleus optical potential parameters are discussed.
Magnetic moments of exotic pentaquarks in the chiral quark-soliton model
Hyun-Chul Kim,Michal Praszalowicz
Physics , 2003, DOI: 10.1016/j.physletb.2004.01.067
Abstract: We investigate the magnetic moments of the baryon antidecuplet within the framework of the chiral quark-soliton model in the chiral limit in a ``\emph{model-independent}'' approach. Sum rules for the magnetic moments are derived. The magnetic moment of $\Theta^{+}$ is found to be about $0.2\sim 0.3 \mu_{N}$.
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