Jin Woo Park

Seoul National University Hospital, Sŏul, Seoul, South Korea

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Publications (98)185.01 Total impact

  • Joonho Bae, Jin Woo Park
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    ABSTRACT: We investigated whether leflunomide can be delivered topically and metabolized into teriflunomide through the skin, and evaluated the therapeutic effect of topical leflunomide. Permeation of leflunomide across and formation of its active metabolite within the skin was examined ex vivo. Deposition of teriflunomide in micropig knee joints after applying topical and transdermal patches containing leflunomide was investigated by determining the plasma and joint tissue concentrations. Finally, the anti-inflammatory effects and inhibition of skin sensitization by topical leflunomide were evaluated in a rat adjuvant arthritis model and mice with delayed-type induced hypersensitivity. We found that after topical application of leflunomide on freshly excised mouse, rat and guinea pig skin, ∼24% of the permeated drug existed as teriflunomide. In micropigs treated topically with leflunomide on the knee joint, significantly lower teriflunomide concentrations were found in plasma, but its concentrations in the knee joint were 3.4-fold to 54.6-fold higher than those after oral administration. In a rat arthritis model, the plasma concentration of teriflunomide after treatment with 10% leflunomide topical solution was 7.54-fold lower than that after 10 mg/kg oral leflunomide. However, topical leflunomide was nearly as effective as oral in inhibiting paw edema (37% versus 56%, respectively). The values for hypersensitized mouse ear weight after treatment with topical leflunomide decreased significantly by 26% compared to vehicle. These results demonstrate that topically applied leflunomide can be delivered effectively and deposited as teriflunomide in an arthritic joint, possibly allowing better compliance in rheumatoid arthritis patients by avoiding leflunomide's side effects.
    Drug Development and Industrial Pharmacy 05/2015; DOI:10.3109/03639045.2015.1044906 · 2.01 Impact Factor
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    ABSTRACT: Impaired facial emotion recognition is a core deficit in schizophrenia. Oxytocin has been shown to improve social perception in patients with schizophrenia; however, the effect of oxytocin on the neural activity underlying facial emotion recognition has not been investigated. This study was aimed to assess the effect of a single dose of intranasal oxytocin on brain activity in patients with schizophrenia using an implicit facial emotion recognition paradigm. Sixteen male patients with schizophrenia and 16 age-matched healthy male control subjects participated in a randomized, double blind, placebo-controlled crossover trial at Seoul National University Hospital. Delivery of a single dose of 40 IU intranasal oxytocin and the placebo was separated by 1 week. Drug conditions were compared by performing a region of interest (ROI) analysis of the bilateral amygdala on responses to the emotion recognition test. It was found that nasal spray decreased amygdala activity for fearful emotion and increased activity for happy faces. Further, oxytocin elicited differential effects between the patient and control groups. Intranasal oxytocin attenuated amygdala activity for emotional faces in patients with schizophrenia, whereas intranasal oxytocin significantly increased amygdala activity in healthy controls. Oxytocin-induced BOLD signal changes in amygdala in response to happy faces was related to attachment style in the control group. Our result provides new evidence of a modulatory effect of oxytocin on neural response to emotional faces for patients with schizophrenia. Future studies are needed to investigate the effectiveness of long-term treatment with intranasal oxytocin on neural activity in patients with schizophrenia.Neuropsychopharmacology accepted article preview online, 10 February 2015. doi:10.1038/npp.2015.41.
    Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 02/2015; DOI:10.1038/npp.2015.41 · 7.83 Impact Factor
  • Joonho Bae, Jin Woo Park
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    ABSTRACT: We prepared an injectable depot system for the long-term delivery of alendronate using a solid/water/oil/water multiple emulsion technique with poly(lactic-co-glycolic acid) as a carrier. The microparticles were spherical with smooth surfaces, ranging from 20 to 70μm in size. The microspheres (ALD-HA-RG504H-MC70) were optimally prepared by introducing a viscous material (hyaluronic acid) and a co-solvent system in the inner aqueous and oil phases, respectively, and showed a significantly increased drug encapsulation efficacy (>70%); the initial burst release was <10% after 1 day. In vitro drug release from ALD-HA-RG504H-MC70 followed zero-order kinetics for approximately 4 weeks and the alendronate plasma level was maintained for more than 1 month after intramuscular injection in rabbits. The ovariectomized (OVX) rats with ALD-HA-RG504H-MC70 injected intramuscularly (0.9mg alendronate/kg/4 weeks) had 112% and 482% increased bone mineral density and trabecular area in the tibia than the OVX controls, respectively, and showed significant improvements in trabecular microarchitecture and bone strength. Furthermore, the major biomarkers of bone turnover revealed that ALD-HA-RG504H-MC70 suppressed effectively the progression of osteoporosis and facilitated new bone formation. Therefore, this sustained release depot system may improve patient compliance and therapeutic efficacy by reducing dose amounts and frequency with minimal adverse reactions. Copyright © 2015. Published by Elsevier B.V.
    International Journal of Pharmaceutics 01/2015; 480(1-2). DOI:10.1016/j.ijpharm.2015.01.020 · 3.79 Impact Factor
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    ABSTRACT: Here we report that the H3K9 demethylase KDM3B represses transcription of the angiogenesis regulatory gene, ANGPT1. Negative regulation of ANGPT1 by KDM3B is independent of its Jumanji (JmjC) domain-mediated H3K9 demethylase activity. We demonstrate that KDM3B downregulates ANGPT1 via interaction with SMRT, and suggest that the repressor complex is formed at the promoter area of ANGPT1. Using MTT and wound healing assays, depletion of KDM3B was found to increase cell proliferation and cell motility, indicating that KDM3B has a role in angiogenesis.
    BMB reports 11/2014; · 1.99 Impact Factor
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    Il-Hong Bae, Jin Woo Park, Dae-Yong Kim
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    ABSTRACT: Exogenous administration of growth factors has potential benefits in wound healing; however, limited percutaneous absorption, inconsistent efficacy, and the need for high doses have hampered successful clinical use. To overcome these restrictions, we focused on the development of a topical formulation composed of highly skin-permeable multimeric nanocomplex of growth factors. In the present study, we fused low-molecular-weight protamine (LMWP) with epidermal growth factor (EGF), insulin-like growth factor 1 (IGF-I), and platelet-derived growth factor A ligand (PDGF-A) (producing recombinant [r]LMWP-EGF, rLMWP-IGF-I, and rLMWP-PDGF-A, respectively) via genetic modification. Then, we used in vitro cell proliferation studies to assess the biological activity and the benefits of the combination. The LMWP-conjugated growth factors were complexed with low-molecular-weight heparin (LMWH) and formulated with Poloxamer 188 as a delivery vehicle. After confirming the enhanced skin permeability, in vivo studies were performed to assess whether the LMWP-conjugated growth factor nanocomplex formulations accelerated the healing of full-thickness wounds in mice. The LMWP-conjugated growth factors were biologically equivalent to their native forms, and their combination induced greater fibroblast proliferation. rLMWP-EGF showed significantly enhanced permeability and cumulative permeation, and the rates for rLMWP-IGF-I and rLMWP-PDGF-A, across excised mouse skin, were 124% and 164% higher, respectively, than for the native forms. The LMWP-fused growth factors resulted in formation of nanocomplexes (23.51±1.12 nm in diameter) in combination with LMWH. Topical delivery of growth factors fused with LMWP accelerated wound re-epithelialization significantly, accompanied by the formation of healthy granulation tissue within 9 days compared with a free-growth factor complex or vehicle. Thus, the LMWP-conjugated growth factor nanocomplex can induce rapid, comprehensive healing and may be a candidate wound-healing therapeutic.
    International Journal of Nanomedicine 09/2014; 9:4551-67. DOI:10.2147/IJN.S68399 · 4.20 Impact Factor
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    ABSTRACT: As the main input hub of the basal ganglia, the striatum receives projections from the cerebral cortex. Many studies have provided evidence for multiple parallel corticostriatal loops based on the structural and functional connectivity profiles of the human striatum. A recent resting-state fMRI study revealed the topography of striatum by assigning each voxel in the striatum to its most strongly correlated cortical network among the cognitive, affective, and motor networks. However, it remains unclear what patterns of striatal parcellation would result from performing the clustering without subsequent assignment to cortical networks. Thus, we applied unsupervised clustering algorithms to parcellate the human striatum based on its functional connectivity patterns to other brain regions without any anatomically or functionally defined cortical targets. Functional connectivity maps of striatal subdivisions, identified through clustering analyses, were also computed. Our findings were consistent with recent accounts of the functional distinctions of the striatum as well as with recent studies about its functional and anatomical connectivity. For example, we found functional connections between dorsal and ventral striatal clusters and the areas involved in cognitive and affective processes, respectively, and between rostral and caudal putamen clusters and the areas involved in cognitive and motor processes, respectively. This study confirms prior findings, showing similar striatal parcellation patterns between the present and prior studies. Given such striking similarity, it is suggested that striatal subregions are functionally linked to cortical networks involving specific functions rather than discrete portions of cortical regions. Our findings also demonstrate that the clustering of functional connectivity patterns is a reliable feature in parcellating the striatum into anatomically and functionally meaningful subdivisions. The striatal subdivisions identified here may have important implications for understanding the relationship between corticostriatal dysfunction and various neurodegenerative and psychiatric disorders.
    PLoS ONE 09/2014; 9(9):e106768. DOI:10.1371/journal.pone.0106768 · 3.53 Impact Factor
  • Huanyu Zhou, Jin‐Woo Park
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    ABSTRACT: In this study, we investigated the factors that determine the efficiency of flexible organic light emitting diodes (f-OLEDs) in relation to transparent conductive electrodes (TCE). Indium tin oxide (ITO) was selected as the TCE and was deposited on polyimide substrates. Controlling the sputtering conditions, ITOs with various degrees of crystallinity were made. Flexible OLEDs (f-OLED) were fabricated on the ITOs, and the current density (J)–luminescence (L)–voltage (V) characteristics of the f-OLEDs were evaluated. The experimental results revealed that the sheet carrier density and surface roughness of ITO are significantly increased and reduced, respectively, as the film crystallinity increased over a certain degree. Based on our X-ray photoelectron spectroscopy (XPS) analysis, chemical bonds formed between the mostly crystallized ITO and a hole transfer layer (HTL) in f-OLEDs, deposited on ITO. To the contrary, In and Sn of the less crystallized ITO diffused into HTL with no formation of interfacial bonds, which may become barriers to carrier flows through HTL. The f-OLED on the mostly crystalline ITO showed significantly better J–L–V characteristics than on the less crystallized ITO, which proved that the crystallinity of ITO is the critical factor that determines the performance of the flexible organic devices constructed on the ITO.
    Physica Status Solidi (A) Applications and Materials 09/2014; 212(2). DOI:10.1002/pssa.201431550 · 1.53 Impact Factor
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    ABSTRACT: Background Human MutY glycosylase homolog (hMYH), a component of the base excision repair pathway, is responsible for the generation of apurinic/apyrimidinic sites. Rad9-Rad1-Hus1 (9-1-1) is a heterotrimeric protein complex that plays a role in cell cycle checkpoint control and DNA repair. In humans, hMYH and 9-1-1 interact through Hus1 and to a lesser degree with Rad1 in the presence of DNA damage. In Saccharomyces pombe, each component of the 9-1-1 complex interacts directly with SpMYH. The glycosylase activity of hMYH is stimulated by Hus1 and the 9-1-1 complex and enhanced by DNA damage treatment. Cells respond to different stress conditions in different manners. Therefore, we investigated whether Rad9 interacted with hMYH under different stresses. Here, we identified and visualized the interaction between hRad9 and hMYH and investigated the functional consequences of this interaction. Results Co-IP and BiFC indicates that hMYH interacts with hRad9. As shown by GST-pull down assay, this interaction is direct. Furthermore, BiFC with deletion mutants of hMYH showed that hRad9 interacts with N-terminal region of hMYH. The interaction was enhanced by hydroxyurea (HU) treatment. mRNA and protein levels of hMYH and hRad9 were increased following HU treatment. A marked increase in p-Chk1 (S345) and p-Cdk2 (T14, Y15) was observed. But this phosphorylation decreased in siMYH- or siRad9-transfected cells, and more pronounced decrease observed in co-transfected cells. Conclusions Our data reveal that hRad9 interacts directly with N-terminal region of hMYH. This interaction is enhanced by HU treatment. Knockdown of one or both protein result in decreasing Chk1 and Cdk2 phosphorylation. Since both protein functions in the early detection of DNA damage, we suggest that this interaction occurs early in DNA damage pathway.
    BMC Molecular Biology 08/2014; 15(1):17. DOI:10.1186/1471-2199-15-17 · 2.06 Impact Factor
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    ABSTRACT: Thrombogenesis is a major cause of morbidity and mortality in cancer patients. Prophylaxis with low-molecular-weight heparin (LMWH) is recommended for cancer patients, but requires non-parenteral delivery methods for long-term treatments. In this study, we sought to generate a new oligomeric-bile acid conjugate of LMWH that can be used for oral delivery. We first synthesized a tetramer of deoxycholic acid (tetraDOCA), which was site-specifically conjugated at the end saccharide of LMWH. When LMWH-tetraDOCA conjugate (LHe-tetraD) was orally administered at a dose of 5mg/kg in ICR mice, the maximum anti-factor Xa level was increased up to 0.62±0.05IU/mL without any evidence of liver toxicity, gastrointestinal damage, or thrombocytopenia. The cancer-associated thrombosis was induced in tumor-bearing mice by local heat application, and the fibrin deposition in tumors was evaluated. The oral administration of LHe-tetraD (either a single dose or multiple daily doses for up to 10days) in mice substantially abolished the coagulation-dependent tropism of fibrinogen in the heated tumors and significantly decreased hemorrhage, compared to the mice treated with saline or subcutaneous injection of LMWH. Thus, the anticoagulation effect of oral LHe-tetraD invokes the benefits of oral delivery and promises to provide an effective and convenient treatment for cancer patients at risk of thrombosis.
    Journal of Controlled Release 05/2014; 195. DOI:10.1016/j.jconrel.2014.05.027 · 7.26 Impact Factor
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    ABSTRACT: To prepare oral controlled-release cilostazol formulations and evaluate their pharmacokinetics and pharmacodynamics in dogs and humans compared with a commercial twice-daily immediate-release formulation (Pletal), thereby showing the potential for the development of an improved once-daily cilostazol formulation. Six different controlled-release preparations were formulated using a micronized cilostazol, solubilizer/absorption enhancer and erodible hydrogel. In-vitro drug release profiles were tailored by varying hydrogel viscosity. Pharmacokinetics and pharmacodynamic (antithrombotic) efficacy were evaluated in beagle dog model of arterial thrombosis. Finally, their pharmacokinetics and pharmacodynamics were also evaluated in healthy human volunteers after single and multiple oral administrations. Hydrogel viscosity-dependent sustained drug release profiles were observed with zero-order release kinetics during 8-12 h. In dogs and humans, compared with Pletal, prolonged drug absorption profiles were observed in the two controlled-release formulations studied. In dogs, the controlled-release formulations showed greater antithrombotic efficacy than twice-daily Pletal. In humans, the antithrombotic efficacy of the selected once-daily cilostazol formulation was equivalent to that of twice-daily Pletal after single and multiple administrations. The prepared oral controlled-release cilostazol formulation may provide prolonged drug absorption and sufficient therapeutic efficacy, potentially serving as an oral once-daily cilostazol formulation to improve patient compliance.
    02/2014; DOI:10.1111/jphp.12227
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    ABSTRACT: Docetaxel is a potent anticancer drug, but development of an oral formulation has been hindered mainly due to its poor oral bioavailability. In this study, solid lipid nanoparticles (SLNs) surface-modified by Tween 80 or D-alpha-tocopheryl poly(ethylene glycol 1000) succinate (TPGS 1000) were prepared and evaluated in terms of their feasibility as oral delivery systems for docetaxel. Tween 80-emulsified and TPGS 1000-emulsified tristearin-based lipidic nanoparticles were prepared by a solvent-diffusion method, and their particle size distribution, zeta potential, drug loading, and particle morphology were characterized. An in vitro release study showed a sustained-release profile of docetaxel from the SLNs compared with an intravenous docetaxel formulation (Taxotere®). Tween 80-emulsified SLNs showed enhanced intestinal absorption, lymphatic uptake, and relative oral bioavailability of docetaxel compared with Taxotere in rats. These results may be attributable to the absorption-enhancing effects of the tristearin nanoparticle. Moreover, compared with Tween 80-emulsified SLNs, the intestinal absorption and relative oral bioavailability of docetaxel in rats were further improved in TPGS 1000-emulsified SLNs, probably due to better inhibition of drug efflux by TPGS 1000, along with intestinal lymphatic uptake. Taken together, it is worth noting that these surface-modified SLNs may serve as efficient oral delivery systems for docetaxel.
    International Journal of Nanomedicine 01/2014; 9:495-504. DOI:10.2147/IJN.S56648 · 4.20 Impact Factor
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    ABSTRACT: The study involved estimation of the Quorum Sensing Inhibition (QSI) potential of aqueous extracts of three of plant leaves viz. pine needle, green tea and mugwort against the soft rot pathogen, Pectobacterium carotovorum in Tobacco system. In an agar well diffusion assay, the extracts showed QSI activity against the bio-indicator bacteria, P. aureofaciens strain 30-84. However the extracts at the tested concentration did not show bactericidal/antibiotic effect. In the initial screening performed in vitro, using tobacco seedlings, all the extracts under study showed QSI activity upon challenge inoculation with P. carotovorum. Green tea leaf extracts rendered the highest level of disease suppression (93%) followed by leaf extracts of Mugwort and pine needle. Experiments were repeated under greenhouse conditions and found that the crude extracts significantly reduced disease symptoms upon challenge with the pathogen. The results suggested that commercial pine needle, mugwort and green tea extracts could significantly destabilize the QS mediated pathogenicity in P. carotovorum - Tobacco system and be effectively applied for the control of soft rot. The extracts are also expected to work well with QS mediated pathogenicity in other plants, which requires further detail study. Also it offers an environmentally friendly means of plant protection.
    Journal of Pure and Applied Microbiology 01/2014; 8(1):63. · 0.07 Impact Factor
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    ABSTRACT: Intestinal transporters are limited to the transport of small molecular substrates. Here, we describe the development of apical sodium-dependent bile acid transporter (ASBT)-targeted high-affinity oligomeric bile acid substrates that mediate the transmembrane transport of low molecular weight heparin (LMWH). Several oligomers of deoxycholic acid (oligoDOCA) were synthesized to investigate the substrate specificity of ASBT. To see the binding of oligoDOCA on the substrate-binding pocket of ASBT, molecular docking was used and the dissociation rate constants (KD) were measured using surface plasmon resonance. The KD for tetrameric DOCA (tetraDOCA) was 50-fold lower than that for monomeric DOCA, because tetraDOCA interacted with several hydrophobic grooves in the substrate-binding pocket of ASBT. The synthesized oligoDOCA compounds were subsequently chemically conjugated to macromolecular LMWH. In vitro, tetraDOCA-conjugated LMWH (LHe-tetraD) had highest selectivity for ASBT during its transport. Orally administered LHe-tetraD showed remarkable systemic anticoagulation activity and high oral bioavailability of 33.5±3.2% and 19.9±2.5% in rats and monkeys, respectively. Notably, LHe-tetraD successfully prevented thrombosis in a rat model of deep vein thrombosis. These results represent a major advancement in ASBT-mediated LMWH delivery and may facilitate administration of many important therapeutic macromolecules through a non-invasive oral route.
    Journal of Controlled Release 12/2013; DOI:10.1016/j.jconrel.2013.12.001 · 7.26 Impact Factor
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    ABSTRACT: DNA double-strand breaks (DSBs) can cause either cell death or genomic instability. The Ku heterodimer Ku70/80 is required for the NHEJ (non-homologous end-joining) DNA DSB repair pathway. The INHAT (inhibitor of histone acetyltransferases) complex subunit, SET/TAF-Iβ, can inhibit p300- and PCAF-mediated acetylation of both histone and p53, thereby repressing general transcription and that of p53 target genes. Here, we show that SET/TAF-Iβ interacts with Ku70/80, and that this interaction inhibits CBP- and PCAF-mediated Ku70 acetylation in an INHAT domain-dependent manner. Notably, DNA damage by UV disrupted the interaction between SET/TAF-Iβ and Ku70. Furthermore, we demonstrate that overexpressed SET/TAF-Iβ inhibits recruitment of Ku70/80 to DNA damage sites. We propose that dysregulation of SET/TAF-Iβ expression prevents repair of damaged DNA and also contributes to cellular proliferation. All together, our findings indicate that SET/TAF-Iβ interacts with Ku70/80 in the nucleus and inhibits Ku70 acetylation. Upon DNA damage, SET/TAF-Iβ dissociates from the Ku complex and releases Ku70/Ku80, which are then recruited to DNA DSB sites via the NHEJ DNA repair pathway.
    Cellular and Molecular Life Sciences CMLS 12/2013; 71(14). DOI:10.1007/s00018-013-1525-8 · 5.86 Impact Factor
  • Jin Woo Park, Youngro Byun
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    ABSTRACT: Risedronate is widely used clinically to treat osteoporosis, Paget's disease, hypercalcemia, bone metastasis, and multiple myeloma. However, its oral efficacy is restricted due to its low bioavailability and severe gastrointestinal adverse effects. This study was designed to evaluate the effect of deoxycholic acid derivatives on the permeability and oral bioavailability of risedronate by increasing its lipophilicity and affinity to bile transporters. We synthesized two bile acid derivatives, N (α)-deoxycholyl-L-lysyl-methylester (DCK) and N (α)-deoxycholyl-L-lysyl-hydroxide (HDCK) as oral absorption enhancers. After ionic complex formation with the bile acid derivatives, the complexes were characterized by powder X-ray diffraction. Their artificial membrane permeabilities and bioavailabilities in rats were investigated in comparison with pure risedronate. Complex formation with DCK or HDCK demonstrated that risedronate existed in an amorphous form in the complex. A physical complex of risedronate with DCK enhanced the apparent membrane permeability of risedronate significantly but pure risedronate was not permeable. An in vivo study revealed that the C max and AUClast of risedronate/DCK (1:2) complex were 1.92- and 2.64-fold higher than those of pure risedronate, respectively. Thus, the risedronate/DCK complex can improve the oral absorption of risedronate and patient compliance by reducing dose frequency and adverse reactions.
    Archives of Pharmacal Research 11/2013; 37(12). DOI:10.1007/s12272-013-0297-x · 1.75 Impact Factor
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    ABSTRACT: We evaluated the laser induced burn wound healing efficacy of a recombinant low-molecular-weight protamine conjugated epidermal growth factor (rLMWP-EGF). rLMWP-EGF was prepared by genetically combining LMWP with the N-terminal sequence of EGF; we obtained a homogeneous modified EGF without reduced biological activity. Because of the protein transduction domain of LMWP, rLMWP-EGF showed enhanced drug penetration across artificial skin constructs and excised mouse skin layers versus EGF and showed significantly improved burn wound healing efficacy, with accelerated wound closure and minimized eschar and scar formation, compared with EGF or no treatment. Histological examination also revealed that rLMWP-EGF permeated through the intact skin around the wound and facilitated residual epithelial cell proliferation in an integrated manner to reform an intact epidermis. Radiofrequency microwound formation was effective for reducing large hypertrophic scars formed after severe laser burning by collagen remodeling but rLMWP-EGF did not show a meaningful synergistic effect in burn scar reduction. However, rLMWP-EGF was helpful for forming skin with a more normal appearance and texture. Thus, rLMWP-EGF demonstrated therapeutic potential as a novel topical burn wound healing drug with no obvious toxic effect. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci.
    Journal of Pharmaceutical Sciences 11/2013; 102(11). DOI:10.1002/jps.23725 · 3.01 Impact Factor
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    ABSTRACT: A flexible transparent electrically conductive film (FTCF) was formed on a poly(ethylene terephthalate) film by spraying single-walled carbon nanotubes dispersed with sodium dodecyl benzene sulfonate in water and, to improve the electrical conductivity of FTCF, the effect on plasma treatment followed by nitric acid treatment was investigated. The Ar plasma treatment was effective in dissociating the surfactant and removing impurities attached to the surface of the carbon nanotubes (CNTs). Therefore, through a cyclic treatment composed of an Ar plasma treatment and nitric acid treatment, more effective removal of surfactant and impurities attached to the spray-coated CNTs could be obtained than a cyclic treatment without the plasma treatment. With the optimized cyclic treatment, the sheet resistance (Ωs) of the spray-coated CNTs could be decreased up to 45% by removing most of the surfactant and impurities. Using the repeated cyclic treatment, the FTCF having the Ωs of 160 Ω/\square at 81.5% optical transmittance at the wavelength of 550 nm could be obtained.
    Japanese Journal of Applied Physics 07/2013; 52(7):5102-. DOI:10.7567/JJAP.52.075102 · 1.06 Impact Factor
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    ABSTRACT: We investigated sandwich structure of the conventional absorber metamaterials to expand the study on dual-band absorption in our previous work (2013 Appl. Phys. Lett. 102 081122). The advantages of the artificial structuring of plasmonic resonators or 'meta-atoms' were exploited to gradually enhance/degrade the absorption peaks by polarization angle of electromagnetic wave. By reshaping the rings at the font of slab, dual- or single-peak absorption is controlled. The absorber is demonstrated in the GHz region.
    06/2013; 4(3):035009. DOI:10.1088/2043-6262/4/3/035009
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    ABSTRACT: In this study, a novel drug-carrying micelle composed of methoxy poly(ethylene glycol) (mPEG)-b-poly(L-lactic acid) (PLLA) with gas-forming carbonate linkage was fabricated. Here, the gas-forming carbonate linkage was formed by the chemical coupling of the terminal hydroxyl group of the PLLA block and benzyl chloroformate (BC). mPEG-b-PLLA-BC was self-organized in aqueous solution: the PEG block on the hydrophilic outer shell and the PLLA-BC block in the hydrophoboic innor core. The cleavage of carbonate linkage by hydrolysis and formation of carbon dioxide nanobubbles in the micellar core enabled an accelerated release of the encapsulated anticancer drug (doxorubicin: DOX) from the mPEG-b-PLLA-BC micelles. The amount of drug (DOX) released from the mPEG-b-PLLA-BC micelle was higher than that from the conventional mPEG-b-PLLA micelle, which allowed for increased in vitro toxicity against KB tumor cells. Copyright © 2013 John Wiley & Sons, Ltd.
    Polymers for Advanced Technologies 06/2013; 24(6). DOI:10.1002/pat.3116 · 1.96 Impact Factor
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    ABSTRACT: Rubidium carbonate (Rb2CO3)-doped tris(8-quinolinolato)aluminum (III) (Alq3) thin films have been investigated as electron-injecting materials for organic light-emitting diodes (OLEDs). Electron-only devices consisting of glass/tin-doped indium oxide (ITO)/Rb2CO3-doped Alq3 (10 nm)/aluminum (Al) showed an electron-ohmic contact property between the electrode and the organic layer at the doping concentration of 10% and higher. The electron-injecting ability of these contacts was largely enhanced by the n-doping effect of Rb2CO3 into the Alq3 layer. The ultraviolet photoemission spectra revealed that when the doping concentration was increased, the n-doping effect reduced the carrier-injecting barrier height by lowering the work function at the Rb2CO3-doped Alq3 interfaces. Also, the x-ray photoemission spectra showed that as the doping concentration was increased at the interfaces, Alq3 molecules decomposed in a chemical reaction with Rb2CO3. The OLED device, having the glass/ITO/molybdenum oxide (MoOx, 25%)-doped N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB, 5 nm)/NPB (63 nm)/Alq3 (32 nm)/Rb2CO3-doped Alq3 (10%, 10 nm)/Al (100 nm) structure, showed the best performance at the optimal doping concentration of Rb2CO3-doped Alq3, both the maximum luminance of 114 400 cd/m2 at the bias voltage of 9.8 V and the power efficiency of 2.7 lm/W at the luminance of 1000 cd/m2 were obtained.
    Journal of Vacuum Science & Technology A Vacuum Surfaces and Films 05/2013; 31(3):031101-031101-7. DOI:10.1116/1.4798302 · 2.14 Impact Factor

Publication Stats

543 Citations
185.01 Total Impact Points

Institutions

  • 2001–2015
    • Seoul National University Hospital
      • • Department of Neuropsychiatry
      • • Department of Anesthesiology and Pain Medicine
      • • Department of Rehabilitation Medicine
      Sŏul, Seoul, South Korea
  • 2013–2014
    • Mokpo National University
      • College of Pharmacy
      Mokuho, Jeollanam-do, South Korea
    • Sungkyunkwan University
      • School of Advanced Materials Science and Engineering (AMSE)
      Sŏul, Seoul, South Korea
    • Gyeongsang National University
      • School of Materials Science and Engineering
      Shinshū, South Gyeongsang, South Korea
    • Vietnam Academy of Science and Technology
      • Institute of Materials Science
      Kanh-Hoa, Khánh Hòa, Vietnam
    • Chosun University
      Gwangju, Gwangju, South Korea
    • Chung-Ang University
      • College of Natural Sciences
      Sŏul, Seoul, South Korea
  • 2010–2014
    • Yonsei University
      • Department of Materials Science and Engineering
      Sŏul, Seoul, South Korea
    • Soonchunhyang University
      Onyang, Chungcheongnam-do, South Korea
    • University of Seoul
      • Depatrment of Materials Science and Engineering
      Sŏul, Seoul, South Korea
  • 2003–2014
    • Seoul National University
      • • School of Mechanical and Aerospace Engineering
      • • Department of Materials Science and Engineering
      Sŏul, Seoul, South Korea
  • 2012–2013
    • Amorepacific Corporation
      Sŏul, Seoul, South Korea
    • National Academy of Agricultural Science (South Korea)
      Sŏul, Seoul, South Korea
    • Dongguk University
      Sŏul, Seoul, South Korea
    • Amore Pacific
      New York, New York, United States
  • 2000–2013
    • Hanyang University
      • • Division of Chemical Engineering and Bioengineering
      • • Department of Physics
      Sŏul, Seoul, South Korea
  • 2011
    • Union Corporation, South Korea
      Sŏul, Seoul, South Korea
    • Korea Aerospace University
      • Department of Business Administration
      Kōyō, Gyeonggi-do, South Korea
  • 2001–2011
    • Korea University
      • Department of Electrical Engineering
      Sŏul, Seoul, South Korea
  • 2002–2009
    • Chonbuk National University
      • School of Medicine
      Tsiuentcheou, North Jeolla, South Korea
  • 2001–2008
    • Pusan National University
      • Division of Electrical and Electronics Engineering
      Tsau-liang-hai, Busan, South Korea
  • 1999–2005
    • Kyungpook National University
      • • Department of Polymer Science and Engineering
      • • Department of Electronic Engineering
      • • Department of Electrical Engineering
      Daikyū, Daegu, South Korea
    • Korea Institute of Science and Technology
      Sŏul, Seoul, South Korea
  • 2004
    • Korea Hydro and Nuclear Power - Central Research Institute
      Sŏul, Seoul, South Korea
  • 1998
    • Chonbuk National University Hospital
      Sŏul, Seoul, South Korea