Ju Hyun Park

Korea University, Sŏul, Seoul, South Korea

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Publications (43)98.73 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In previous studies, 30Kc19, a lipoprotein in silkworm hemolymph, enhanced productivity and glycosylation by expression of a 30Kc19 gene or supplementation with a recombinant 30Kc19 protein. Additionally, 30Kc19 exhibited enzyme-stabilizing and cell-penetrating abilities in vitro. In this study, we hypothesized that supplemented 30Kc19 penetrated into the cell and enhanced the stability of the cellular enzyme. We investigated this using in vitro and cellular assessments. The activity of sialyltransferase (ST) and isolated mitochondrial complex I/III was enhanced with 30Kc19 in dose-dependent manner while initial reaction rate was unchanged, suggesting that 30Kc19 enhanced enzyme stability rather than specific activity. For intracellular enzyme activity assessment, ST activity inside erythropoietin (EPO)-producing Chinese hamster ovary (CHO) cells increased more than 25 % and mitochondrial complex II activity in HeLa cells increased more than 50 % with 30Kc19. The increase in intracellular ST activity resulted in an increase in sialic acid content of glycoproteins produced in CHO cells supplemented with 30Kc19. Similarly, enhanced mitochondrial complex activity increased mitochondrial membrane potential and ATP production in HeLa cells with 30Kc19 by over 50 %. Because 30Kc19 stabilized intracellular enzymes for glycosylation and enhanced protein productivity with supplementation in the culture medium, we expect that 30Kc19 can be a valuable tool for effective industrial recombinant protein production.
    Applied Microbiology and Biotechnology 09/2014; · 3.81 Impact Factor
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    ABSTRACT: Cell-penetrating peptides (CPPs) or protein transduction domains (PTDs) have attracted increasing attention due to their high potential to deliver various, otherwise impermeable, bioactive agents, such as drugs and proteins across cell membranes. A number of CPPs have been discovered since then. Recently, 30Kc19 protein has attracted attention because it was the first cell-penetrating protein that has been found in insect hemolymph. Here, we report a cell-penetrating peptide derived from 30Kc19 protein, VVNKLIRNNKMNC, which efficiently penetrates cells when supplemented to medium for mammalian cell culture. Moreover, like other CPPs, this “Pep-c19” also efficiently delivered cell-impermeable cargo proteins, such as green fluorescent protein (GFP) into cells. In addition to the in vitro system, Pep-c19 exhibited the cell-penetrating property in vivo. When Pep-c19 was intraperitoneally injected into mice, Pep-c19 successfully delivered cargo proteins into various organ tissues with higher efficiency than the 30Kc19 protein itself, and without toxicity. Our data demonstrates that Pep-c19 has a great potential as a cell-penetrating peptide that can be used as a therapeutic tool to efficiently deliver different cell-impermeable cargo molecules into the tissues of various organs.
    PROCESS BIOCHEMISTRY 09/2014; · 2.52 Impact Factor
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    ABSTRACT: Recently, the recombinant 30Kc19 protein, originating from silkworm hemolymph of Bombyx mori has attracted attention due to its cell-penetrating property and potential application as a protein delivery system. However, this observation of penetration across cell membrane has raised questions concerning the interaction of the protein-lipid bilayer. Here, we report a dimerization propensity of the 30Kc19 protein in the presence of amphiphilic moieties; SDS or phospholipid. Native PAGE showed that the 30Kc19 monomer formed a dimer when SDS or phospholipid was present. In the GST pull-down assay, supplementation of the 30Kc19 protein to mammalian cell culture medium showed dimerization and penetration; due to phospholipids at the cell membrane, the main components of the lipid bilayer. Mutagenesis was performed, and penetration was observed by 30Kc19 C76A and not 30Kc19 C57A, which meant that the presence of cysteine at position 57 (Cys-57) is involved in dimerization of the 30Kc19 at the cell membrane during penetration. We anticipate application of the native 30Kc19 protein with high cell-penetrating efficiency for delivery of cargos to various cell types. The intracellular cargo delivery using the 30Kc19 protein is a non-virus derived (e.g. TAT) delivery method, which can open up new approaches for the delivery of therapeutics in bioindustries, such as pharma- and cosmeceuticals.
    Biotechnology Journal 08/2014; · 3.71 Impact Factor
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    ABSTRACT: a b s t r a c t In this study, we investigate the effect of the roughness height of bottom electrodes (BEs) on the resistive switching properties of a 1 Â 1 platinum/nickel nitride/nickel (Pt/NiN/Ni) capacitor crossbar array (CBA) resistive random access memory (ReRAM) cell. The thickness of the rough surface is varied from 40 nm to 80 nm. In the resistive switching tests, the set voltage in the current–voltage (I–V) curves is reduced by using a rough surface (RS) BE in the Si wafer, and the reset current is reduced by increasing the surface roughness height of the Si wafer. On the other hand, there is a reduction in V SET/RESET and I SET/RESET variations in the I–V curves over 100 repetitive switching cycles when a surface roughness of 40 nm is employed. Further, for the CBA ReRAM, the current is the most stable when using the 40 nm-thick RS Si wafer at the high-resistance state and low-resistance state for 300,000 s in the retention test. These results show that use of the roughness substrate in the CBA ReRAM structure is effective in reducing var-iations in operating voltage and current. Ó 2014 Published by Elsevier B.V.
    Microelectronic Engineering 08/2014; 126:169-172. · 1.34 Impact Factor
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    ABSTRACT: The metal nanocrystals (NCs) embedded-NiN-based resistive random access memory cells are demonstrated using several metal NCs (i.e., Pt, Ni, and Ti) with different physical parameters in order to investigate the metal NC's dependence on resistive switching (RS) characteristics. First, depending on the electronegativity of metal, the size of metal NCs is determined and this affects the operating current of memory cells. If metal NCs with high electronegativity are incorporated, the size of the NCs is reduced; hence, the operating current is reduced owing to the reduced density of the electric field around the metal NCs. Second, the potential wells are formed by the difference of work function between the metal NCs and active layer, and the barrier height of the potential wells affects the level of operating voltage as well as the conduction mechanism of metal NCs embedded memory cells. Therefore, by understanding these correlations between the active layer and embedded metal NCs, we can optimize the RS properties of metal NCs embedded memory cells as well as predict their conduction mechanisms.
    Journal of Applied Physics 03/2014; 115(9):094305-094305-5. · 2.19 Impact Factor
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    ABSTRACT: We demonstrate highly uniform resistive-switching (RS) characteristics of an SiN nanorod (NR) device fabricated by nanosphere lithography. In the RS experiments, variations in set and reset voltages for the SiN NR device are dramatically reduced to 0.2 V from 0.45 V in conventional SiN thin films. In addition, the resistance ratio (10 3) between set and reset states is larger and stably maintained without any degradation. As a result, in the resistive random access memory (RRAM) cells with a filament-based RS mechanism, the RS behavior of NR-based RS materials is more uniform than that of the conventional films as a result of reducing the number of conducting paths in the SiN layer.
    Applied Physics Express 01/2014; 7(2):024202. · 2.73 Impact Factor
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    ABSTRACT: The improvement of resistive switching (RS) phenomena of silicon-nitride (SiNx)-based resistive random access memory (ReRAM) cells through oxygen doping process was investigated. As a result, compared to un-doped SiNx films, the oxygen doped SiNx (SiNx:O2)-based ReRAM cells show a lower current (∼0.3 μA) level at a high resistance state and a smaller variation of operating voltage through the reduction of leakage current in the SiNx:O2 film by combining silicon dangling bonds and doped oxygen ions. Therefore, we believe that the oxygen doping process in SiNx films can effectively improve the RS characteristics of SiNx-based ReRAM cells. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    physica status solidi (RRL) - Rapid Research Letters 12/2013; · 2.39 Impact Factor
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    ABSTRACT: Nanoparticles have been widely used for delivering various chemical and biomolecular drugs, such as anti-cancer drugs and therapeutic proteins. Among nanoparticles, protein nanoparticles have advantages of non-cytotoxicity and biodegradability. In this study, a recombinant 30Kc19 protein was applied to human serum albumin (HSA) nanoparticles to enhance cellular uptake and stability of a nanoparticle cargo enzyme. The 30Kc19 protein, which originates from silkworm, has cell-penetrating and enzyme-stabilizing abilities. Therefore, 30Kc19-HSA nanoparticles were expected to enhance cellular uptake and stability of an enzyme loaded on the nanoparticles. Here, nanoparticles loaded with β-galactosidase were prepared using the desolvation method. The 30Kc19-HSA nanoparticles were uniformly spherical in shape, dispersed evenly in phosphate buffered saline and cell culture media, and released β-galactosidase in a sustained manner. The 30Kc19-HSA nanoparticles had negligible toxicity to animal cells and exhibited enhanced cellular uptake and intracellular stability of β-galactosidase in HeLa and HEK293 cells when compared with those of HSA nanoparticles. These results suggest that 30Kc19-HSA protein nanoparticles could be used as a versatile tool for drug delivery to various cells.
    Biomaterials 11/2013; · 8.31 Impact Factor
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    ABSTRACT: Psoriatic arthritis is a chronic inflammatory form of arthritis that is associated with psoriasis. A 54-yr-old male with chronic psoriatic temporomandibular joint arthritis and myofascial pain was treated using methotrexate and a myofascial pain protocol. Jaw pain improved after 3 weeks, however, tenderness to palpation of muscles remained. Comprehensive evaluation and multidisciplinary clinical treatment is required for the treatment of patients with psoriatic temporomandibular joint arthritis.
    Journal of Dental Rehabilitation and Applied Science. 06/2013; 29(2).
  • New Physics: Sae Mulli. 04/2013; 63(4):466.
  • Seong Hyung Kim, Ju Hyun Park, Ji Kang Park
    Journal of the Korean Society of Radiology. 01/2013; 69(1):23.
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    ABSTRACT: Cell-penetrating protein and its protein transduction domain have been used to deliver drugs and proteins into the cells via receptor-independent endocytosis. A number of cell-penetrating proteins including TAT derived from HIV-1 virus, VP22 from herpes simplex virus and Antennapedia from drosophila have been discovered. Here, we report a cell-penetrating protein, 30Kc19, originating from the hemolymph of silkworm, Bombyx mori. The 30Kc19 is the first cell-penetrating protein that has been found in insect hemolymph. When the 30Kc19 protein produced from recombinant Escherichia coli was supplemented into the medium for mammalian cell culture, 30Kc19 efficiently penetrated into various types of cells and localized at subcellular compartments including mitochondria and cytoplasm. 30Kc19 also delivered cargo proteins such as green fluorescence protein into the cells even though cargo proteins are not able to penetrate into cells by themselves. In addition to the in vitro system, 30Kc19 exhibited the protein transduction property in vivo. When 30Kc19 was intraperitoneally injected into mice, 30Kc19 delivered cargo proteins into various organ tissues of model animals without producing toxicity. Therefore, 30Kc19 has a great potential as a cell-penetrating protein that can be used as a medicinal tool to deliver cargo molecules including proteins into the target organ tissues in the body.
    Biomaterials 09/2012; 33(35):9127-34. · 8.31 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the sequential MRI findings of intramuscular gossypiboma and to correlate them with the pathologic findings in rabbits. Sterile gauze was packed in the hamstring muscles of 12 rabbits, and sequential MR images were obtained 1, 2, and 4 weeks and 2, 6, and 12 months after gauze insertion. Two rabbits were sacrificed at each time point. Their pathologic findings were compared with the MRI findings on each date. At the acute stage, the gossypibomas appeared as areas of heterogeneous low signal intensity on T2-weighted MR images with inflammatory change around the gossypiboma. In the subacute stage, the gossypibomas appeared as areas of peripheral low and central high signal intensity with wavy stripes of low signal intensity on T2-weighted images. On contrast-enhanced fat-suppressed T1-weighted images, the peripheral enhancement of the masses advanced toward the center of the mass as the fibrocollagenization between the gauze bundles progressed centrally. In the chronic stage, on contrast-enhanced fat-suppressed T1-weighted images, central advancement of the peripheral enhancement occurred according to the maturation of the fibrocollagenization. Calcifications around individual gauze fibers were observed 6-12 months after gauze insertion. On sequential contrast-enhanced fat-suppressed T1-weighted images of rabbits, intramuscular gossypiboma exhibited a chronologic centripetal enhancement pattern for 1 year mainly owing to concentric progression of fibrocollagenization between gauze bundles toward the center of the mass.
    American Journal of Roentgenology 07/2012; 199(1):W114-22. · 2.74 Impact Factor
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    ABSTRACT: We previously reported that the expression of Bombyx mori 30Kc19 gene in CHO cells significantly improved both the production and sialylation of recombinant human EPO (rHuEPO) in adhesion culture mode. In this study, the effects of 30Kc19 expression and supplementation of 30Kc19 recombinant protein on the productivity and glycosylation pattern of rHuEPO were investigated in the serum-free suspension culture mode. Especially, glycosylation pattern was examined in detail using a quantitative MALDI-TOF MS method. The expression of 30Kc19 increased the EPO production by 2.5-folds and the host cells produced rHuEPO with more complex glycan structures and a larger content of sialic acid and fucose. The glycan structures of rHuEPO in the 30Kc19-expressing cell consisted of bi-, tri-, tetra-, and penta-antennary branching (35, 18, 33, and 14 %, respectively), while the control cells produced predominantly bi-antennary branching (70 %). About 53 % of the glycans from rHuEPO in the 30Kc19-expressing cell was terminally sialylated, while no obvious sialylated glycan was found in the control cells. The percentage of fucosylated glycans from the 30Kc19-expressing cell culture was 77 %, whereas only 61 % of the glycans from the control cell were fucosylated glycans. We also examined whether these effects were observed when the recombinant 30Kc19 protein produced from Escherichia coli was supplemented into the culture medium for CHO cells. In the control cell line without the 30Kc19 gene, EPO production increased by 41.6 % after the addition of 0.2 mg/mL of the recombinant 30Kc19 protein to the culture medium. By the Western blot analysis after two-dimensional electrophoresis (2-DE) of isoforms of EPO, we confirmed that 30Kc19 enhanced the sialylation of EPO glycans. These results demonstrated that both 30Kc19 gene expression and the recombinant 30Kc19 protein addition enhanced rHuEPO productivity and glycosylation in suspension culture. In conclusion, the utilization of 30Kc19 in CHO cell culture holds great promise for use in the manufacturing of improved biopharmaceutical glycoproteins.
    Applied Microbiology and Biotechnology 06/2012; 96(3):671-83. · 3.81 Impact Factor
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    ABSTRACT: In previous studies, we reported that the 30K protein originating from the silkworm inhibited apoptosis in mammalian cells. In this work, we demonstrated that the 30Kc19 protein, which is most abundant 30K protein in silkworm hemolymph, also enhanced enzyme stability. When the recombinant 30Kc19 protein was supplemented into distilled–deionized water containing alkaline phosphatase or horseradish peroxidase, deactivation of both enzymes induced by non-buffered DDW was significantly suppressed. The increase in enzyme stability due to the presence of 30Kc19 was similar to that observed for bovine serum albumin, which is commonly used in conventional enzyme reactions. The decrease in enzyme activity due to long-term storage in different buffer systems was also inhibited by 30Kc19. The 30Kc19 protein structure was shown to play a vital role in stabilizing the enzyme. These results imply that the recombinant 30Kc19 protein hold promise for use as an additive to increase or maintain enzyme activity.
    Process Biochemistry - PROCESS BIOCHEM. 01/2012;
  • Chae Hoon Sohn, Ju Hyun Park
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    ABSTRACT: The damping characteristics of three-type resonators, a half-wave, a quarter-wave, and a Helmholtz resonator are studied experimentally by adopting linear acoustic test. A quantitative acoustic property of sound absorption coefficient in a model enclosure with the resonators is measured and thereby, the acoustic-damping capacity of a resonator is characterized. For a comparative study on acoustic damping, the damping capacity of a half-wave resonator is compared with that of the other resonators. A half-wave and a quarter-wave resonators have the same damping mechanism, but a quarter-wave resonator has much larger damping capacity than a half-wave resonator with the same diameter of a single resonator. It is found that shorter length of a resonator has the advantage of longer one with respect to the damping capacity. The damping capacity of a Helmholtz resonator increases with cavity volume and does as the orifice length decreases. A Helmholtz resonator has the highest damping capacity of three-type resonators and a half-wave resonator has the lowest. Besides, a Helmholtz resonator requires the smallest number of resonators for optimal damping. The design criterion of each resonator on the optimal damping is provided by the normalized parameter of open-area ratio and the similarity behavior for the optimal damping is observed for various enclosure diameters.
    Aerospace Science and Technology 12/2011; 15(8):606-614. · 1.00 Impact Factor
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    ABSTRACT: The purpose of this study was to prospectively evaluate interobserver agreement on lesion detection and characterization in the review of automated ultrasound images of the breast by five radiologists. From August to October 2009, bilateral whole-breast ultrasound examinations were performed with an automated technique and with a handheld device for 55 women consecutively scheduled to undergo diagnostic ultrasound. Three-dimensional volume data from automated ultrasound were reviewed by five radiologists, who were unaware of the results of ultrasound with a handheld device and mammography and of the clinical information. If a lesion was detected with automated ultrasound, clock-face position, distance from the nipple, largest diameter, and BI-RADS final assessment category were evaluated. If the lesion was a mass, shape, orientation, margin, echogenicity, and posterior feature were analyzed. Intraclass correlation coefficients and kappa statistics were used for statistical analysis. At least two observers identified 145 lesions with automated ultrasound. Among 725 possible detections, 587 (81%) detections were made. Individual investigators detected between 74% (107/145) and 88% (127/145) of the lesions. The rate of detection of lesions larger than 1.2 cm was 92%. Most lesions detected only with handheld ultrasound (11/12, 92%) or automated ultrasound (34/36, 94%) were cysts or probably benign masses. All intraclass correlation coefficients for lesion location and size exceeded 0.75, indicating high reliability. Substantial agreement was found for mass shape (κ = 0.71), orientation (κ = 0.72), margin (κ = 0.61), and BI-RADS final assessment category (κ = 0.63). Detection of lesions larger than 1.2 cm in greatest diameter was reliable. High reliability was obtained for reporting lesion size and location. Substantial agreement was obtained for description of key feature and final assessment category.
    American Journal of Roentgenology 09/2011; 197(3):747-54. · 2.74 Impact Factor
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    ABSTRACT: We developed a simple and facile method of producing a stable aqueous suspension of reduced graphene oxide (RGO) nanosheets through the chemical reduction of graphene oxide in the presence of a conducting polymer dispersant, poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). This approach involves the cooperative interactions of strong π- π interactions between a two-dimensional graphene sheet and a rigid backbone of PEDOT and the intermolecular electrostatic repulsions between negatively charged PSS bound on the RGO sheets, which impart the colloidal stability of the resulting hybrid nanocomposite of RGO/PEDOT. Moreover, our one-step solution-based method allows preserving the intrinsic chemical and electronic properties of both components, yielding a hybrid film of RGO nanosheets of high conductivity of 2.3 kΩ/sq with a transmittance of 80%. By taking advantage of conducting network structure of conducting polymers which provides an additional flexibility and mechanical stability of RGO nanosheets, we demonstrate the potential application of hybrid RGO/PEDOT as highly flexible and transparent electrodes.
    Langmuir 03/2011; 27(5):2014-8. · 4.38 Impact Factor
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    ABSTRACT: Productivity and sialylation are two important factors for the production of recombinant glycoproteins in mammalian cell culture. In our previous study, we found that silkworm hemolymph increased the sialylation of recombinant secreted human placental alkaline phosphatase in the insect cells, promoted the transfer of sialic acids onto the glycoprotein oligosaccharides in an in vitro asialofetuin sialylation system, and enhanced recombinant protein production in the Chinese hamster ovary (CHO) cells. These beneficial effects were mainly due to the 30K proteins, which consist of five isoforms. Among the 30K proteins, 30Kc19 was determined to be the major component. In this study, the 30Kc19 gene was introduced into a CHO cell line producing recombinant human erythropoietin, and its effects on productivity and sialylation were investigated. The transient expression of 30Kc19 significantly improved the production and sialylation of EPO. A stable cell line containing 30Kc19 was also established to investigate the effect of 30Kc19 gene expression. The stable expression of 30Kc19 increased the production and sialylation by 102.6% and 87.1%, respectively. The enhanced productivity from 30Kc19 expression is believed to occur because the 30Kc19 protein suppresses the loss of mitochondrial membrane potential and consequently improves the generation of intracellular ATP. In addition, the positive effect of 30Kc19 expression on sialylation is believed to be due to its ability to maintain sialyltransferase activity. In conclusion, 30Kc19 expression is a novel approach to improve the production and sialylation of recombinant glycoproteins in CHO cells.
    Biotechnology and Bioengineering 02/2011; 108(7):1634-42. · 4.16 Impact Factor
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    ABSTRACT: Over-expression of anti-apoptotic cloned-genes is a widely used strategy for inhibiting apoptosis in mammalian cell culture. In our previous study, we reported Bombyx mori30K gene improved the production of recombinant proteins in Chinese hamster ovary (CHO) cells. In this study, we reengineered the CHO cells with the 30Kc6 gene and 30Kc19 gene for the production of a therapeutic monoclonal antibody (mAb) directed against the glycoprotein receptor of human platelets. After the medium was changed from serum containing one to serum-free one, expression of 30Kc6 in CHO cells increased the cell viability by 40.8% in 4 days and mAb production by 2.3-fold in 5 days. However, no significant changes in cell viability and mAb production were observed for the cells expressing 30Kc19. In the case of the cells expressing 30Kc6, the specific production rate was also improved. The expression of the 30Kc6 gene increased the cell viability and productivity because it maintained the mitochondrial membrane potential (MMP) and reduced the downstream cascade responses for apoptosis. These results indicate that 30Kc6 outperformed 30Kc19 in terms of cell death-protective capability and the production of monoclonal antibodies in CHO cells.
    PROCESS BIOCHEMISTRY 12/2010; 45(12):1852-1856. · 2.52 Impact Factor

Publication Stats

201 Citations
98.73 Total Impact Points


  • 2013–2014
    • Korea University
      • Department of Electrical Engineering
      Sŏul, Seoul, South Korea
  • 2007–2014
    • Seoul National University
      • • Department of Chemical and Biological Engineering
      • • School of Chemical and Biological Engineering
      Sŏul, Seoul, South Korea
    • Soonchunhyang University
      • College of Medicine
      Onyang, South Chungcheong, South Korea
  • 2012
    • Jeju National University
      Tse-tsiu, Jeju, South Korea
  • 2009–2011
    • Sejong University
      • Faculty of Food Science and Technology
      Sŏul, Seoul, South Korea
  • 2010
    • Seoul National University Hospital
      • Department of Urology
      Seoul, Seoul, South Korea
    • Yonsei University
      • Department of Oral Medicine
      Seoul, Seoul, South Korea
  • 2005
    • Dongguk University
      • Department of Chemistry
      Seoul, Seoul, South Korea