Kyung Eun Lee

Chonnam National University, Gwangju, Gwangju, South Korea

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Publications (117)421.3 Total impact

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    ABSTRACT: Graphene oxide (GO) is aqueous dispersible oxygenated graphene, which shows colloidal discotic liquid crystallinity. Many properties of GO based materials, including electrical conductivity and mechanical properties, are limited by the small flake size of GO. Unfortunately, typical sonochemical exfoliation of GO from graphite generally leads to broad size and shape distribution. Here, we introduce a facile size selection of large size GO exploiting liquid crystallinity and investigate on the size dependent N-doping and oxygen reduction catalysis. In the biphasic GO dispersion that both isotropic and liquid crystalline phases are equilibrated, large size GO flakes (> 20 μm) are spontaneously concentrated within the liquid crystalline phase. N-doping and reduction of the size selected GO exhibits that N-dopant type is highly dependent on GO flake size. Large size GO demonstrates quaternary dominant N-doping and the lowest onset potential (-0.08 V) for oxygen reduction catalysis, signifying that quaternary N-dopants serve for principal catalytic sites in N-doped graphene.
    ACS Nano 08/2014; · 12.03 Impact Factor
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    ABSTRACT: House dust mites (HDMs) are an important source of indoor allergens associated with asthma, rhinitis and atopic dermatitis. Chicken immunoglobulin (Ig) Y is known to be a good alternative to mice and rabbit antibody production. In this study, we produced IgYs specific to HDMs and investigated their IgE immunoreactivities.
    Yonsei medical journal. 07/2014; 55(4):999-1004.
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    ABSTRACT: Objective. Allopurinol-induced severe cutaneous adverse reactions (SCARs) are relatively rare, but cause high rates of morbidity and mortality. Studies have shown that the HLA-B5801 allele and renal impairment are strongly associated with SCARs. Recent American College of Rheumatology guideline recommends that, prior to treatment with allopurinol, the HLA–B5801 genotype of gout patients at high risk for SCARs, including Korean patients with chronic renal insufficiency, should be determined. However, whether such genotyping is cost-effective is unknown. This study evaluated the cost-effectiveness of HLA-B5801 genotyping for treatment of gout in patients with chronic renal insufficiency in Korea.Methods. A decision analytic model over a time period of 12 months was employed to compare the cost and outcomes of treatment informed by HLA-B5801 genotyping with that of a conventional treatment strategy using a hypothetical cohort of gout patients with chronic renal insufficiency. Direct medical costs were obtained from real SCAR patients from two tertiary hospitals. Outcomes were measured as a total expected cost and an incremental cost-effectiveness ratio.Results. In the base model, the total expected cost and probability of continuation of gout treatment without SCARs with the conventional and HLA-B5801 screening strategies were US $1,193 and US $1,055, and 97.8% and 100%, respectively. The result was robust according to sensitivity analyses.Conclusion. Our model suggests that gout treatment informed by HLA-B5801 genotyping is less costly and more effective than treatment without genotyping, and HLA-B5801 genotyping could considerably reduce the occurrence of allopurinol-induced SCARs and related deaths. © 2014 American College of Rheumatology.
    Arthritis Care & Research. 07/2014;
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    ABSTRACT: In general, traditional gene carriers contain strong cationic charges to efficiently load anionic genes, but this cationic character also leads to destabilization of plasma membranes and causes severe cytotoxicity. Here, we developed a PCR-based nano-factory as a safe gene delivery system. A few template plasmid DNA can be amplified by PCR inside liposomes about 200 nm-diameters and the quantity of loaded genes highly increased by more than 8.8 fold. The liposome membrane was composed of neutral lipids free from cationic charges. Consequently, this system is non-toxic, unlike other traditional cationic gene carriers. Intense RFP expression in CHO-K1 cells showed that the amplified genes could be successfully transfected to cells. Animal experiments with luciferase gene also showed in vivo gene expression by our system without toxicity. We think that this PCR-based nano-factory system can overcome the toxicity problem that is the critical limitation of current gene delivery to clinical application.
    ACS Nano 04/2014; · 12.03 Impact Factor
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    ABSTRACT: Valosin-containing protein (VCP), also known as p97, is an AAA(+) ATPase that plays an essential role in a broad array of cellular processes including the endoplasmic reticulum-associated degradation (ERAD) pathway. Recently, ERAD-specific deubiquitinating enzymes have been reported to be physically associated with VCP, although the exact mechanism is not yet clear. Among these enzymes is ovarian tumor domain-containing protein 1 (OTU1). Here, we report the structural basis for interaction between VCP and OTU1. The crystal structure of the UBXL domain of OTU1 (UBXLOTU1) complexed to the N-terminal domain of VCP (NVCP) at 1.8 Å-resolution reveals that UBXLOTU1 adopts a ubiquitin-like fold and binds at the interface of two subdomains of NVCP using the (39)GYPP(42) loop of UBXLOTU1 with the two prolines in cis- and trans-configurations, respectively. Mutagenesis study shows that this loop is not only critical for the interaction with VCP but also for its role in the ERAD pathway. Negative staining EM shows that one molecule of OTU1 binds to one VCP hexamer with a KD of 0.71 μM. Analytical size exclusion chromatography demonstrates that OTU1 can bind VCP in both the presence and absence of a heterodimer formed by ubiquitin-fusion degradation protein 1 (UFD1) and nuclear localization protein 4 (NPL4).
    Journal of Biological Chemistry 03/2014; · 4.65 Impact Factor
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    ABSTRACT: We report a remarkably rapid method for assembling pristine graphene platelets into a large area transparent film at a liquid surface. 2-3 layer pristine graphene platelets temporally solvated with NMP are assembled at the surface of a dilute aqueous suspension using an evaporation-driven Rayleigh-Taylor instability and then are driven together by Marangoni forces. The platelets are fixed through physical binding of their edges. Typically, 8-cm-diameter circular graphene films are generated within two minutes. Once formed, the films can be transferred onto various substrates with flat or textured topologies. This interfacial assembly protocol is generally applicable to other nanomaterials, including 0D fullerene and 1D carbon nanotubes, which commonly suffer from limited solution compatibility.
    Nano Letters 02/2014; · 13.03 Impact Factor
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    ABSTRACT: How a pool of undifferentiated neural progenitor cells is maintained in the developing nervous system is an issue that remains unresolved. One of the key transcription factors for self-renewal of these cells is Sox2, the forced expression of which has been shown to inhibit neuronal differentiation in vivo. To dissect the molecular mechanisms of Sox2 activity, a ChIP-on-chip assay has been carried out for Sox2, and multiple candidate direct target genes have been isolated. In this report, we provide evidence indicating that Sox6, which like Sox2 belongs to the SRY-related HMG box transcription factor family, is a bona-fide direct regulatory target of Sox2. In vivo, Sox6 expression is seen with a temporal lag in Sox2-positive neural precursor cells in the ventricular zone, and Sox2 promotes expression of Sox6 as a transcriptional activator. Interestingly, gain- and loss-of-function assays indicate that Sox6 in turn is required for the maintenance of Sox2 expression, suggesting that a positive feedback loop, which functions to inhibit premature neuronal differentiation, exists between the two transcription factors.
    Proceedings of the National Academy of Sciences 02/2014; · 9.81 Impact Factor
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    ABSTRACT: Apical sodium-dependent bile acid transporters (ASBT) are the intestinal transporters that form intermediate complexes with substrates and its conformational change drives the movement of substrates across the cell membrane. However, membrane-based intestinal transporters are confined to the transport of only small molecular substrates. Here, we propose a new strategy that uses high-affinity binding macromolecular substrates to functionally transform the membrane transporters so that they behave like receptors, ultimately allowing the apical-basal transport of bound macromolecules. Bile acid based macromolecular substrates were synthesized and allowed to interact with ASBT. ASBT/macromolecular substrate complexes were rapidly internalized in vesicles, localized in early endosomes, dissociated and escaped the vesicular transport while binding of cytoplasmic ileal bile acid binding proteins cause exocytosis of macromolecules and prevented entry into lysosomes. This newly found transformation process of ASBT suggests a new transport mechanism that could aid in further utilization of ASBT to mediate oral macromolecular drug delivery.
    Scientific Reports 01/2014; 4:4163. · 5.08 Impact Factor
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    ABSTRACT: To evaluate the efficacy of mesenchymal stem cells (MSCs) encapsulated in self-assembled peptide (SAP) hydrogels in a rat knee model for the prevention of osteoarthritis (OA) progression.
    International Journal of Nanomedicine 01/2014; 9 Suppl 1:141-57. · 4.20 Impact Factor
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    ABSTRACT: Layer-by-layer gelation of reduced graphene oxide through spontaneous reduction at a metal surface is developed by S. O. Kim and co-workers on page 615. This allows 3D shape engineering and arbitrary scaling up, according to need. Gel sheets with a porous hydrated network show excellent energy-storage performances when they are used as supercapacitor electrodes, demonstrating a high areal capacity as well as a high rate capability.
    Advanced Materials 01/2014; 26(4):505. · 14.83 Impact Factor
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    ABSTRACT: The objective of this study was to investigate the pharmacokinetic characteristics of levodopa (L-dopa) from nasal powder formulations using highly water-soluble levodopa methyl ester hydrochloride (LDME). In vivo pharmacokinetic studies were carried out with formulated LDME nasal powders. After oral and intravenous administration of L-dopa and carbidopa and intranasal administration LDME to the rat, L-dopa concentrations were determined in plasma and the brain using high-performance liquid chromatography. The absolute bioavailabilities of nasal preparations with and without Carbopol were 82.4 and 66.7 %, respectively, which were much higher than that of oral delivery (16.2 %). The drug-targeting efficiencies [area under the curve (AUC) in brain/AUC in plasma] of L-dopa in the nasal formulations (0.98-1.08) were much higher than that of oral preparation (0.69). These results suggest that LDME nasal powder formulations would be useful delivery systems of L-dopa to the brain.
    European Journal of Drug Metabolism and Pharmacokinetics 12/2013; · 1.31 Impact Factor
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    ABSTRACT: We compared the volatile profiles in soy sauce according to inoculation with Tetragenococcus halophilus and/or Zygosaccharomyces rouxii. Totals of 107 and 81 volatiles were respectively identified by using solid-phase microextraction and solvent extraction. The various volatile compounds identified included acids, aldehydes, esters, ketones, furans and furan derivatives, and phenols. The major volatiles in the samples treated with T. halophilus were acetic acid, formic acid, benzaldehyde, methyl acetate, ethyl 2-hydroxypropanoate, 2-hydroxy-3-methyl-2-cyclopenten-1-one, and 4-hydroxy-3-methoxybenzaldehyde, while those in the samples inoculated with Z. rouxii were mainly ethanol, acetaldehyde, ethyl propanoate, 2/3-methylbutanol, 1-butanol, 2-phenylethanol, ethyl 2-methylpropanoate, and 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone. The results indicate that T. halophilus produced significant acid compounds and could affect the Z. rouxii activity, supporting the notion that yeasts and lactic acid bacteria respectively have different metabolic pathways of alcoholic fermentation and lactic acid fermentation, and produce different dominant volatile compounds in soy sauce.
    Bioscience Biotechnology and Biochemistry 11/2013; · 1.27 Impact Factor
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    ABSTRACT: The lipid entities of cell membranes are components of the immune system and important mediators of inflammation. Despite increasing interest in the function of epithelial cells in inflammation, the role of cholesterol in this process has not been described. Here, we investigated the effect of cholesterol depletion on the inflammatory process in airway epithelial cells via the expression of interleukin (IL)-8 as a marker of inflammation. A 549 cells were treated with 0.5% methyl-β-cyclodextrin as a selective cholesterol extractor. The IL-8 level was assessed by enzyme-linked immunosorbent assay and reassessed after cholesterol repletion. Mitogen-activated protein kinase (MAPK) inhibitors were used to determine the upstream signaling pathway for IL-8 production in cholesterol-depleted cells. We found a relationship between the amount of cholesterol in A 549 cells and inflammation of the airway. IL-8 production was increased in cholesterol-depleted A 549 cells and restored by cholesterol repletion. IL-8 production was decreased by pretreatment with the extracellular signal-regulated kinase (ERK) inhibitor U0126 but not with JNK inhibitor II or the p38 MAPK inhibitor SB202190. Our findings suggest that inflammatory responses are increased in cholesterol-depleted epithelial cells via the MAPK signaling system, predominantly by the ERK pathway. We conclude that the lipid components of airwayepithelial cells may play a role in the inflammatory process.
    Allergy, asthma & immunology research 11/2013; 5(6):402-8. · 2.65 Impact Factor
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    ABSTRACT: We have investigated the gas chemistry of marine sediments (up to 250mbelow seafloor,mbsf) recovered during the Second Ulleung Basin Gas Hydrate Drilling Expedition (UBGH2) to identify and compare the gas origin and its migration at seismically non-chimney, truncated chimney and chimney sites in this basin. The molecular and isotopic data (C1/C2þ ratios > 300, d13CCH4 < �65&, and dDCH4 < �181&) of the gases indicate that methane predominantly originates via microbial carbon dioxide reduction. The carbon isotopic fractionation ( 3 c) between methane and carbon dioxide below 30mbsf has a relatively constant value ( 3 c ¼ 66e68) at all sites, consistent with the microbial pathway. In contrary, samples shallower than 30 m bsf display significant differences with the seismic characteristics of each site. 3 c ranges from 65 to 81 in non-chimney sites but shows values as low as 45 in chimney sites, which is agreement with previously reported piston core data (Kim et al., 2012), and thought to reflect two-phase methane transport processes. In chimney sites, deep-sourced methane migrates independently of the carbon dioxide, which remains dissolved in the aqueous phase leading to the extremely low 3c values observed in the upper 30 m bsf. Upward methane diffusion at non-chimney sites may also add a transport-induced fractionation as evidenced in mixing diagrams, but this process does not significantly affect the 3 c values.d13CCO2 shows usually minimum values at the SulfateeMethane Transition Zone (SMTZ) at all sites. However, in chimney sites, these values have a much more depleted signature, indicating faster rates of methane consumption by Anaerobic Oxidation of Methane (AOM) supported by the higher methane flux. Moreover, here the massive hydrate that forms in shallow sediments incorporates gases with a lower C1/ C2 ratio (¼higher C2/C1) than the surrounding sediment, as documented in hydrate-bound gas (BG) and void gas (VG) samples. Gas hydrate dissociation during the core recovery is released enriched ethane (C2H6) trapped in gas cage, which leads to have high C2H6 in VG samples.
    Marine and Petroleum Geology 11/2013; 47:113-124. · 2.11 Impact Factor
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    ABSTRACT: This study aimed to investigate the effects of polymorphisms of FMO3 and FMO6 genes on the pharmacokinetics of sulindac sulfide, the active metabolite of sulindac, in patients with preterm labors. Ten single nucleotide polymorphisms (SNPs) were genotyped, and plasma sulindac sulfide concentrations were measured at 0, 1.5, 4, and 10 hr after drug administration. The area under the curve from time 0 to the last sampling time point (AUClast) for sulindac sulfide was obtained. The AUClast of sulindac sulfide was significantly higher in patients with variant-type homozygotes of FMO3 (rs909530) than those with ancestral alleles or heterozygotes. FMO3 (rs2266780) was in complete linkage disequilibrium with FMO6 (rs7885012), and there was a marginal significance between genotypes (P = 0.049). From multiple linear regression models, FMO3 (rs909530) was found to have significant influence on the AUClast of sulindac sulfide after adjusting for gestational age, weight, and all studied SNPs. The predictive contribution of rs909530 to variability of sulindac sulfide AUClast was 27.0 %. In conclusion, the results of this study could help clinicians predict efficacies and side effects of sulindac for developing individualized treatment for patients with preterm labors.
    Drug metabolism and disposition: the biological fate of chemicals 10/2013; · 3.74 Impact Factor
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    ABSTRACT: Alzheimer's disease (AD), one of the most prevalent neurodegenerative brain diseases, has been extensively researched for years. However, its synaptic structure, which is a basis for understanding neurodegenerative disorders, has not yet been understood clearly. Defining the structures of neurons and their synaptic connections is the significant goal of brain research. To study synaptic connectivity, three-dimensional (3D) reconstructions of the nervous system are very helpful. In this study, the 3D structure of brain synapses in the Drosophila melanogaster Swedish amyloid precursor protein (APP) mutant, which is characterized by early onset AD, was analyzed using focused ion beam/scanning electron microscopy (FIB/SEM). This technique is one of the most useful for 3D reconstruction, as the process of obtaining serial images is fully automated and thus avoids the problems inherent in hand-operated ultrathin serial sectioning. The 3D images of normal and AD brains reported in this study reveal characteristic features of AD such as appearance of autophagy, abnormal axon formation and increased mitochondrial size. This 3D analysis reveals structural change as a basis for understanding neurodegenerative disorder.
    Microscopy (Oxford, England). 09/2013;
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    ABSTRACT: This study aims to investigate the feasibility of Levodopa transdermal delivery systems (TDSs). Levodopa TDSs were formulated using various vehicles and permeation enhancers, and in vitro permeation and in vivo pharmacokinetic studies were carried out. In the in vitro study, ester-type vehicles showed relatively high enhancing effects; propylene glycol monocaprylate and propylene glycol monolaurate showed the highest permeation fluxes from both solution and pressure sensitive adhesive (PSA) TDS formulations. Lag time was dramatically shortened with PSA TDS formulations as compared with solution formulations. In the in vivo study, the addition of fatty acids increased blood drug concentrations regardless of the kind or concentration of fatty acid; the AUCinf increased up to 8.7 times as compared with propylene glycol (PG) alone. PSA TDS containing 10% linoleic acid exhibited prolonged Tmax as compared with oral form. Total clearance of L-dopa from PSA TDSs was significantly lower than from oral form (up to 86.8 times). Especially, PSA TDS containing 10% linoleic acid (LOA) revealed 76.2 fold higher AUCinf than oral administration. Based on our results, the L-dopa PSA TDS containing PG with 10% LOA could be used as a good adjuvant therapy for Parkinson's disease patients who experience symptom fluctuation by L-dopa oral administration.
    International Journal of Pharmaceutics 09/2013; · 3.99 Impact Factor
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    ABSTRACT: This study investigated the socio-demographic characteristics and medical causes of death among meteorological disaster casualties and compared them with deaths from all causes. Based on the death data provided by the National Statistical Office from 2000 to 2011, the authors analyzed the gender, age, and region of 709 casualties whose external causes were recorded as natural events (X330-X389). Exact matching was applied to compare between deaths from meteorological disasters and all deaths. The total number of deaths for last 12 years was 2 728 505. After exact matching, 642 casualties of meteorological disasters were matched to 6815 all-cause deaths, which were defined as general deaths. The mean age of the meteorological disaster casualties was 51.56, which was lower than that of the general deaths by 17.02 (p<0.001). As for the gender ratio, 62.34% of the meteorological event casualties were male. While 54.09% of the matched all-cause deaths occurred at a medical institution, only 7.6% of casualties from meteorological events did. As for occupation, the rate of those working in agriculture, forestry, and fishery jobs was twice as high in the casualties from meteorological disasters as that in the general deaths (p<0.001). Meteorological disaster-related injuries like drowning were more prevalent in the casualties of meteorological events (57.48%). The rate of amputation and crushing injury in deaths from meteorological disasters was three times as high as in the general deaths. The new information gained on the particular characteristics contributing to casualties from meteorological events will be useful for developing prevention policies.
    Journal of preventive medicine and public health = Yebang Ŭihakhoe chi. 09/2013; 46(5):261-70.
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    ABSTRACT: The generation of nanosized probes often requires time-intensive and application-specific optimization processes that involve conjugating a nanoconstruct to a targeting moiety. Herein, we genetically modify apoferritin and generate a universal interface system composed of protein G and 6×His-tag. The resulting construct, conferred with modularity and high targeting efficiency, is applied toward two distinct applications in the detection of a pancreatic cancer biomarker and used to demonstrate its potential in the facile exchange of nanoprobe components.
    ACS Nano 08/2013; · 12.03 Impact Factor
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    ABSTRACT: Adolescence is critical in the habituation of diverse lifestyles and is a base for future physical well-being. Although gastrointestinal disorders are frequently reported in adolescents, studies related to GI drug use or related factors in Korean adolescents are rare. Thus, this study examined Korean adolescents for the use of GI drugs for abdominal symptoms and analyzed the associated factors. This cross-sectional study was done with a total of 2,416 students who completed a given questionnaire. The health-related questions included GI medication intake, smoking, alcohol, caffeine, regular exercise, self-cognitive health level, GI symptom, non-steroidal anti-inflammatory drugs (NSAIDs) intake, and sleep problems. In questions about GI medication intake, drugs included digestives and antacids. And the intake of GI drugs more than once during the past 1 month was regarded as taking GI drugs. The sociodemographic questions included age, gender, grade, number of close friends, extracurricular activities, and school performance. The overall prevalence for taking GI drugs, including antacids and digestives, was 17.4 %. When students taking GI drugs were compared with those not taking GI drugs, the former group showed higher rates of girls (P < 0.001) and participants in extracurricular activities (P < 0.05) than the latter group. Factors including alcohol, caffeine, self-cognitive health levels, and GI symptoms showed statistical significance with the rate of GI drug intake. The rate of GI drug intake in NSAID users was 2.7 times higher than that in non-users (P < 0.001). The prevalence rate of every sleep problem was higher in students taking GI medications except snoring, witnessed apnea, and teeth grinding. From the multiple regression, it was found that gender (female), extracurricular activities, alcohol intake, self-cognitive health levels, NSAIDs intake, and nightmares were related factors to GI drug intake. Based on the results, it was conclude that encouragement to build healthy lifestyle habits in adolescents is very important for their academic performances and health status in adulthood.
    Archives of Pharmacal Research 08/2013; · 1.54 Impact Factor

Publication Stats

589 Citations
421.30 Total Impact Points


  • 2014
    • Chonnam National University
      Gwangju, Gwangju, South Korea
  • 2011–2014
    • Korea Institute of Science and Technology
      • Center for Theragnosis
      Sŏul, Seoul, South Korea
  • 2005–2014
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2013
    • Catholic University of Korea
      • Department of Internal Medicine
      Seoul, Seoul, South Korea
  • 2012–2013
    • Korea Advanced Institute of Science and Technology
      • Department of Chemistry
      Seoul, Seoul, South Korea
    • MEDIPOST Biomedical Research Institute
      Sŏul, Seoul, South Korea
    • Sungkyunkwan University
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 2010–2013
    • Ewha Womans University
      • College of Pharmacy
      Sŏul, Seoul, South Korea
    • Yonsei University
      • Department of Obstetrics and Gynecology
      Seoul, Seoul, South Korea
  • 2007–2013
    • Korea University
      • Department of Chemical and Biological Engineering
      Sŏul, Seoul, South Korea
    • Chungbuk National University
      • School of Science Education
      Tsiuentcheou, North Jeolla, South Korea
  • 2005–2013
    • Korea Maritime University
      • • Division of Marine Environment and Bioscience
      • • College of Ocean Science and Technology
      Tsau-liang-hai, Busan, South Korea
  • 2011–2012
    • Dongduk Women's University
      Sŏul, Seoul, South Korea
  • 2007–2010
    • Pohang University of Science and Technology
      • • Department of Chemistry
      • • National Creative Research Initiative Center for Smart Supramolecules and Department of Chemistry
      Geijitsu, North Gyeongsang, South Korea
  • 2005–2010
    • Hannam University
      • • Department of Advanced Materials
      • • Department of Polymer Science and Engineering
      Daiden, Daejeon, South Korea
  • 2006
    • Seoul National University
      Sŏul, Seoul, South Korea