Kwon-Ha Yoon

Wonkwang University, Riri, Jeollabuk-do, South Korea

Are you Kwon-Ha Yoon?

Claim your profile

Publications (97)205.97 Total impact

  • No preview · Article · Apr 2016 · Applied Sciences
  • Tharoeun Thap · Kwon-Ha Yoon · Jinseok Lee
    [Show abstract] [Hide abstract] ABSTRACT: We proposed new electrodes that are applicable for electrocardiogram (ECG) monitoring under freshwater- and saltwater-immersion conditions. Our proposed electrodes are made of graphite pencil lead (GPL), a general-purpose writing pencil. We have fabricated two types of electrode: a pencil lead solid type (PLS) electrode and a pencil lead powder type (PLP) electrode. In order to assess the qualities of the PLS and PLP electrodes, we compared their performance with that of a commercial Ag/AgCl electrode, under a total of seven different conditions: dry, freshwater immersion with/without movement, post-freshwater wet condition, saltwater immersion with/without movement, and post-saltwater wet condition. In both dry and post-freshwater wet conditions, all ECG-recorded PQRST waves were clearly discernible, with all types of electrodes, Ag/AgCl, PLS, and PLP. On the other hand, under the freshwater- and saltwater-immersion conditions with/without movement, as well as post-saltwater wet conditions, we found that the proposed PLS and PLP electrodes provided better ECG waveform quality, with significant statistical differences compared with the quality provided by Ag/AgCl electrodes.
    No preview · Article · Apr 2016 · Sensors
  • No preview · Article · Feb 2016
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Ebselen is a non-toxic seleno-organic drug with anti-inflammatory and antioxidant properties that is currently being examined in clinical trials to prevent and treat various diseases, including atherosclerosis, stroke, and cancer. However, no reports are available for verifying the pharmacological effects of ebselen on major metabolic bone diseases such as osteoporosis. In this study, we observed that ebselen suppressed the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells in an osteoblast/osteoclast co-culture by regulating the ratio of receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin secreted by osteoblasts. In addition, ebselen treatment in the early stage of osteoclast differentiation inhibited RANKL-dependent osteoclastogenesis by decreasing the phosphorylation of IκB, PI3K, and Akt in early signaling pathways and by subsequently inducing c-Fos and nuclear factor of activated T-cells c1. Further, ebselen induced apoptosis of osteoclasts in the late stage of osteoclast differentiation. In addition, ebselen treatment suppressed filamentous actin ring formation and bone resorption activity of mature osteoclasts. Reflecting these in vitro effects, administration of ebselen recovered bone loss and its µ-CT parameters in lipopolysaccharide-mediated mouse model. Histological analysis confirmed that ebselen prevented trabecular bone matrix degradation and osteoclast formation in the bone tissues. Finally, it was proved that the anti-osteoclastogenic action of ebselen is achieved through targeting N-methyl-D-aspartate (NMDA) receptor. These results indicate that ebselen is a potentially safe drug for treating metabolic bone diseases such as osteoporosis.
    Full-text · Article · Feb 2016 · International journal of biological sciences
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Protocatechuic acid (PCA) plays a critical role in nutritional metabolism; it is a major metabolite of anthocyanins, which are flavonoids with a range of health benefits. PCA has a variety of biological activities including anti-oxidant, antiinflammatory, anti-apoptosis, and anti-microbial activities. However, the pharmacological effect of PCA, especially on osteoclastogenesis, remains unknown. We examined the effect of PCA on receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation and bone resorption. PCA dose-dependently inhibited RANKL-induced osteoclast differentiation in mouse bone marrow macrophages (BMMs) and suppressed the bone-resorbing activity of mature osteoclasts. At the molecular level, PCA suppressed RANKL-induced phosphorylation of JNK among MAPKs only, without significantly affecting the early signaling pathway. PCA also suppressed RANKL-stimulated expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1) at the mRNA and protein levels, without altering c-Fos mRNA expression. Additionally, PCA down-regulated the expression of downstream osteoclastogenesis-related genes including β3-integrin, DC-STAMP, OC-STAMP, Atp6v0d2, CTR, and CtsK. Mice treated with PCA efficiently recovered from lipopolysaccharide-induced bone loss in vivo. Thus, PCA inhibits RANKL-induced osteoclast differentiation and function by suppressing JNK signaling, c-Fos stability, and expression of osteoclastic marker genes. These results suggest that PCA could be useful in treatment of inflammatory bone disorders. Copyright
    Full-text · Article · Jan 2016 · Phytotherapy Research
  • [Show abstract] [Hide abstract] ABSTRACT: Objective. The aim of this study was to compare gallstones on virtual unenhanced images and true unenhanced images acquired with dual-energy CT (DECT). Materials and Methods. We enrolled 112 patients with right upper quadrant pain and clinically suspected acute cholecystitis or gallstone who underwent DECT-including unenhanced, arterial, and portal phases. Eighty-three gallstones with composition proven by semiquantitative Fourier transform infrared spectroscopy from 45 patients who had undergone cholecystectomy (40 cholesterol gallstones from 21 patients, 43 calcium gallstones from 24 patients) were included. CT images were retrospectively evaluated for stone size, contrastto-noise ratio (CNR) of gallstone to bile, and visibility and density of gallstones for each image set. The visibility of each type of stone was compared with a paired t test. Results. Both cholesterol and calcium stones measured smaller on virtual unenhanced images than on true unenhanced images, yielding a lower sensitivity of virtual unenhanced images for detecting small gallstones. Mean CNR of cholesterol stones was 2.45 ± 1.32 versus 1.67 ± 1.55 (p < 0.032) and that of calcium stones was 10.59 ± 7.15 and 14.11 ± 9.81 (p < 0.001) for virtual unenhanced and true unenhanced images, respectively. For calcium stones, two readers found 43 of 43 (100%) on true unenhanced images; one reader found 41 of 43 (95%) and the other, 37 of 43 (86%) on virtual unenhanced images. For cholesterol stones, one reader found 20 of 40 (50%) and the other 19 of 40 (47%) on true unenhanced images versus 34 of 40 (85%) and 30 of 40 (75%), respectively, on virtual unenhanced images. The visibility of cholesterol stones was higher on virtual unenhanced images, but that of calcium stones was lower. Conclusion. Virtual unenhanced images at DECT allow better visualization of cholesterol gallstones, but true unenhanced images allow better visualization of calcium and small gallstones.
    No preview · Article · Jan 2016 · American Journal of Roentgenology
  • [Show abstract] [Hide abstract] ABSTRACT: The distribution of healthcare information via cloud-based hospital information systems has been increasing in recent years. Because these systems can disseminate sensitive healthcare information to various smart devices, their security approaches must be carefully studied. In addition, research is required to ensure that patients are being properly notified about changes in their medical treatments. Therefore, in this paper, we propose a dynamic medical information system for digital hospital environments. For this purpose, we design a system that can securely distribute existing digital hospital data, including medical images and patient record information. In order to classify the providing services, we divide them into two types—synchronization and security. We suggest a dynamic authentication method to access medical information. Moreover, the proposed system provides Digital Imaging and Communications in Medicine (DICOM) file synchronization between system environments. We confirm the usefulness of the application based on experimental results.
    No preview · Article · Dec 2015 · Wireless Personal Communications
  • [Show abstract] [Hide abstract] ABSTRACT: X-ray phase-contrast imaging can provide images with much greater soft-tissue contrast than conventional absorption-based images. In this paper, we describe differential X-ray phase-contrast images of insect specimens that were obtained using a grating-based Talbot interferometer and a laboratory X-ray source with a spot size of a few tens of micrometers. We developed the interferometer on the basis of the wavelength, periods, and height of the gratings; the field of view depends on the size of the grating, considering the refractive index of the specimen. The phase-contrast images were acquired using phase-stepping methods. The phase contrast imaging provided a significantly enhanced soft-tissue contrast compared with the attenuation data. The contour of the sample was clearly visible because the refraction from the edges of the object was strong in the differential phase-contrast image. Our results demonstrate that a grating-based Talbot interferometer with a conventional X-ray tube may be attractive as an X-ray imaging system for generating phase images. X-ray phase imaging obviously has sufficient potential and is expected to soon be a great tool for medical diagnostics.
    No preview · Article · Dec 2015 · Journal- Korean Physical Society
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Intraperitoneal injection is a common technique that safely delivers a substance into the peritoneal cavity but can induce high stress in animals. The authors have developed a new method for administering intraperitoneal injections in mice, with the goal of causing less stress during handling and injection. Here, they compare their novel technique with a conventional technique in three experiments. In the first experiment, the authors administered intraperitoneal injections of contrast medium using either technique and then used micro-computed tomography to evaluate the placement and retention of the medium. In the second and third experiments, the authors administered intraperitoneal injections or control treatments, then sampled blood to determine circulating concentrations of stress-related hormones. Imaging showed that both the novel and the conventional techniques properly delivered a contrast medium into the peritoneal cavity. The novel technique was also associated with lower concentrations of stress-related hormones than was the conventional technique. These results indicate that this novel technique might be beneficial to investigators that use intraperitoneal injections with mice.
    Full-text · Article · Oct 2015 · Lab Animal
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Ingestion of Citrus unshiu Markovich (CUM) has been widely used as an alternative therapy for thousands years in Korean traditional medicine. Both anti-osteoclastic actions of CUM extracts (CUME) and the possibility for development as a healthy food product were investigated. CUME significantly (p<0.05) and dose-dependently diminished the receptor activator of nuclear factor kappa-B ligand (RANKL)-induced formation of tartrate resistant acid phosphatase (TRAP)-positive osteoclasts. At the molecular level, CUME interrupted osteoclastogenesis based on selective stimulation of ERK and Akt activation. CUME caused down-regulation of osteoclast-specific marker gene expression derived from impairment of c-Fos and nuclear factor of activated T cells c1 (NFATc1) activation. Treatment with CUME caused localization failure of filamentous actin (F-actin) rings during cellularization and, subsequently, mature osteoclasts suffered malfunction of osteolytic activity. CUME has potential for prevention of osteoporosis. © 2015, The Korean Society of Food Science and Technology and Springer Science+Business Media Dordrecht.
    Full-text · Article · Oct 2015 · Food science and biotechnology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Harpagoside (HAR) is a natural compound isolated from Harpagophytum procumbens (devil's claw) that is reported to have anti-inflammatory effects; however, these effects have not been investigated in the context of bone development. The current study describes for the first time that HAR inhibits receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in vitro and suppresses inflammation-induced bone loss in a mouse model. HAR also inhibited the formation of osteoclasts from mouse bone marrow macrophages (BMMs) in a dose-dependent manner as well as the activity of mature osteoclasts, including filamentous actin (F-actin) ring formation and bone matrix breakdown. This involved a HAR-induced decrease in extracellular signal-regulated kinase (ERK) and c-jun N-terminal kinase (JNK) phosphorylation, leading to the inhibition of Syk-Btk-PLCγ2-Ca(2+) in RANKL-dependent early signaling, as well as the activation of c-Fos and nuclear factor of activated T cells cytoplasmic 1 (NFATc1), which resulted in the down-regulation of various target genes. Consistent with these in vitro results, HAR blocked lipopolysaccharide (LPS)-induced bone loss in an inflammatory osteoporosis model. However, HAR did not prevent ovariectomy-mediated bone erosion in a postmenopausal osteoporosis model. These results suggest that HAR is a valuable agent against inflammation-related bone disorders but not osteoporosis induced by hormonal abnormalities.
    Full-text · Article · Aug 2015 · Journal of Natural Products
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Pemetrexed, a multitarget antifolate used to treat malignant mesothelioma and non-small cell lung cancer (NSCLC), has been shown to stimulate autophagy. In this study, we determined whether autophagy could be induced by pemetrexed and simvastatin cotreatment in malignant mesothelioma and NSCLC cells. Furthermore, we determined whether inhibition of autophagy drives apoptosis in malignant mesothelioma and NSCLC cells. Malignant mesothelioma MSTO-211H and A549 NSCLC cells were treated with pemetrexed and simvastatin alone and in combination to evaluate their effect on autophagy and apoptosis. Cotreatment with pemetrexed and simvastatin induced greater caspase-dependent apoptosis and autophagy than either drug alone in malignant mesothelioma and NSCLC cells. 3-Methyladenine (3-MA), ATG5 siRNA, bafilomycin A, and E64D/pepstatin A enhanced the apoptotic potential of pemetrexed and simvastatin, whereas rapamycin and LY294002 attenuated their induction of caspase-dependent apoptosis. Our data indicate that pemetrexed and simvastatin cotreatment augmented apoptosis and autophagy in malignant mesothelioma and NSCLC cells. Inhibition of pemetrexed and simvastatin-induced autophagy was shown to enhance apoptosis, suggesting that this could be a novel therapeutic strategy against malignant mesothelioma and NSCLC.
    Full-text · Article · Aug 2015 · Oncotarget
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: To evaluate whether suppression of tumor microvasculature by double anti-angiogenic protein (DAAP) treatment could increase the extent of radiofrequency ablation (RFA)-induced coagulation in a murine renal cell carcinoma model. Renal cell carcinoma cell lines were implanted subcutaneously into 10 nude mice. Four mice received adenoviral DAAP treatment and 6 mice received sterile 0.9% saline solution as DAAP-untreated group. The effect of DAAP was evaluated according to the vascularity by contrast-enhanced ultrasound (CEUS) using microbubbles. Four DAAP-treated mice and 4 DAAP-untreated mice were then treated with RFA, resulting in 3 groups: no-therapy (n = 2), RFA only (n = 4), and RFA combined with DAAP treatment (n = 4). Immediately after RFA, the size of coagulation necrosis and mitochondrial enzyme activity were compared between the groups using analysis of variance (ANOVA) and post hoc test. The contrast enhancement ratio for tumor vascularization on CEUS was significantly lower in the DAAP treated group than in DAAP-untreated group (30.2 ± 9.9% vs. 77.4 ± 17.3%; p = 0.021). After RFA, the mean coagulation diameter was 0 mm for no-therapy group, 6.7 ± 0.7 mm for the RFA only group and 8.5 ± 0.4 mm for the RFA with DAAP group (ANOVA, p < 0.001). The area of viable mitochondria within the tumor was 27.9 ± 3.9% in no-therapy group, 10.3 ± 4.5% in the RFA only group, and 2.1 ± 0.7% in the RFA with DAAP group (ANOVA, p < 0.001). Our results suggest the potential value of combining RFA with anti-angiogenic therapy.
    Full-text · Article · Jul 2015 · Korean journal of radiology: official journal of the Korean Radiological Society
  • [Show abstract] [Hide abstract] ABSTRACT: BACKGROUND: Mobile computed tomography (CT) with a cone-beam source is increasingly used in the clinical field. Mobile cone-beam CT (CBCT) has great merits; however, its clinical utility for brain imaging has been limited due to problems including scan time and image quality. OBJECTIVE: The aim of this study was to develop a dedicated mobile volumetric CBCT for obtaining brain images, and to optimize the imaging protocol using a brain phantom. METHODS: The mobile volumetric CBCT system was evaluated with regards to scan time and image quality, measured as signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR), spatial resolution (10% MTF), and effective dose. Brain images were obtained using a CT phantom. RESULTS: The CT scan took 5.14 s at 360 projection views. SNR and CNR were 5.67 and 14.5 at 120 kV/10 mA. SNR and CNR values showed slight improvement as the X-ray voltage and current increased (p < 0.001). Effective dose and 10% MTF were 0.92 mSv and 360 μ m at 120 kV/10 mA. Various intracranial structures were clearly visible in the brain phantom images. CONCLUSIONS: Using this CBCT under optimal imaging acquisition conditions, it is possible to obtain human brain images with low radiation dose, reproducible image quality, and fast scan time.
    No preview · Article · Jul 2015 · Journal of X-Ray Science and Technology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Adipokines derived from adipocytes are important factors that act as circulating regulators of bone metabolism. C1q/tumor necrosis factor (TNF)-related Protein-3 (CTRP3) is a novel adipokine with multiple effects such as lowering glucose levels, inhibiting gluconeogenesis in the liver, and increasing angiogenesis and anti-inflammation. However, the effects and the mechanisms of CTRP3 on bone metabolism, which is regulated by osteoblasts and osteoclasts, have not been investigated. Here, we found that CTRP3 inhibited osteoclast differentiation induced by osteoclastogenic factors in bone marrow cell-osteoblast co-cultures, but did not affect the ratio of receptor activator of nuclear factor κB (NF-κB) ligand (RANKL) to osteoprotegerin (OPG) induced by osteoclastogenic factors in osteoblasts. We also found that CTRP3 inhibited osteoclast differentiation from mouse bone marrow macrophages (BMMs) induced by RANKL in a dose-dependent manner without cytotoxicity. Functionally, CTRP3 inhibited the F-actin formation and bone resorbing activity of mature osteoclasts. Pretreatment with CTRP3 significantly inhibited RANKL-induced expression of c-Fos and nuclear factor of activated T-cells (NFATc1), essential transcription factors for osteoclast development. Surprisingly, the activation of AMP-activated protein kinase (AMPK) was considerably increased by pretreatment with CTRP3 for 1h. The CTRP3-stimulated AMPK activation was also maintained during RANKL-induced osteoclastogenesis. CTRP3 did not affect RANKL-induced p38, ERK, JNK, Akt, IκB, CREB, and calcium signaling (Btk and PLCγ2). These results suggest that CTRP3 plays an important role as a negative regulator of RANKL-mediated osteoclast differentiation by acting as an inhibitor of NFATc1 activation through the AMPK signaling pathway. Furthermore, CTRP3 treatment reduced RANKL-induced osteoclast formation and bone destruction in mouse calvarial bone in vivo based on micro-CT and histologic analysis. In conclusion, these findings strongly suggest that CTRP3 deserves new evaluation as a potential treatment target in various bone diseases associated with excessive osteoclast differentiation and bone destruction. Copyright © 2015. Published by Elsevier Inc.
    Full-text · Article · Jun 2015 · Bone
  • [Show abstract] [Hide abstract] ABSTRACT: Prohibitin-1 (PHB) regulates diverse cellular processes by controlling several signaling pathways. In this study, we investigated the functional involvement of PHB in osteoclast differentiation. PHB expression was time-dependently increased by RANKL in BMMs. However, the retroviral over-expression of PHB strongly inhibited the expression of c-Fos and NFATc1, and activation of p38-Elk-1-SRE signaling pathway. Anti-osteoclastogenic action of PHB was significantly inhibited by constitutively active forms of MKK6, but not Elk-1. Collectively, PHB negatively regulates the formation of mature osteoclasts via inhibition of MKK6 activity that affects the activation of the p38-Elk-1 signaling axis required for the expression of c-Fos and NFATc1. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Jun 2015 · Biochemical and Biophysical Research Communications
  • [Show abstract] [Hide abstract] ABSTRACT: BACKGROUND: Technologies employing digital X-ray devices are developed for mobile settings. OBJECTIVE: To develop a mobile digital X-ray fluoroscopy (MDF) for intraoperative guidance, using a novel flat panel detector to focus on diagnostics in outpatient clinics, operating and emergency rooms. METHODS: An MDF for small-scale field diagnostics was configured using an X-ray source and a novel flat panel detector. The imager enabled frame rates reaching 30 fps in full resolution fluoroscopy with maximal running time of 5 minutes. Signal-to-noise (SNR), contrast-to-noise (CNR), and spatial resolution were analyzed. Stray radiation, exposure radiation dose, and effective absorption dose were measured for patients. RESULTS: The system was suitable for small-scale field diagnostics. SNR and CNR were 62.4 and 72.0. Performance at 10% of MTF was 9.6 lp/mm (53 μm) in the no binned mode. Stray radiation at 100 cm and 150 cm from the source was below 0.2 μGy and 0.1 μGy. Exposure radiation in radiography and fluoroscopy (5 min) was 10.2 μGy and 82.6 mGy. The effective doses during 5-min-long fluoroscopy were 0.26 mSv (wrist), 0.28 mSv (elbow), 0.29 mSv (ankle), and 0.31 mSv (knee). CONCLUSIONS: The proposed MDF is suitable for imaging in operating rooms.
    No preview · Article · Jun 2015 · Journal of X-Ray Science and Technology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: The roots of Ostericum koreanum (OK) Maximowicz have traditionally been used to produce an herbal medicine reported to possess anti-inflammatory, anti-oxidant, antimicrobial, and antitumor activities; however, its effect on bone metabolism has not yet been reported. The present study examined the effects of OK extract on lipopolysaccharide (LPS)-induced bone loss in mice by investigating bone structure and the levels of the receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in serum and bone marrow fluid (BMF). The effects of OK extract on osteoclastogenesis were also investigated in mouse bone marrow macrophages by examining the formation of tartrate-resistant acid phosphatase (TRAP)-positive cells, the actin ring, and bone resorption activity. OK reduced LPS-induced bone destruction in vivo via a decrease in the RANKL/OPG ratio. Furthermore, it suppressed the formation of TRAP-positive cells and the actin ring, and reduced the bone-resorbing activity of mature osteoclasts. OK also significantly down-regulated the expression of various osteoclast-specific genes. However, it did not affect osteoblast differentiation, or the expression of genes involved in this process. These results demonstrated that OK prevented LPS-induced bone loss by decreasing the RANKL/OPG ratio in serum and BMF, and inhibited osteoclast differentiation and function, suggesting that OK represents a potential therapeutic drug for the treatment of osteoclast-associated bone diseases.
    Full-text · Article · May 2015 · The American Journal of Chinese Medicine
  • Young Hwan Lee · Han Ah Lee · Taeyeong Heo · Kwon-Ha Yoon
    No preview · Article · Apr 2015 · Ultrasound in Medicine & Biology
  • Chong-Ho Lee · Jong Hyun Ryu · Young-Hwan Lee · Kwon-Ha Yoon
    [Show abstract] [Hide abstract] ABSTRACT: A dedicated extremity cone-beam computed tomography (CBCT) was introduced recently, rapidly becoming an attractive modality for extremity imaging. This study aimed at evaluating the effectiveness of a curtain shaped lead shielding in reducing the exposure of patients to scattered radiation in dedicated extremity CBCT. A dedicated extremity CBCT scanner was used. The lead shielding curtain was 42 cm x 60 cm with 0.5 mm lead equivalent. Scattered radiation dose from CBCT was measured using thermoluminescence dosimetry chips at 20 points, at different distance and direction from CT gantry. Two sets of scattered radiation dose measurements were performed before and after installation of curtain-shaped lead shield, and percentage reduction in dose in air was calculated. Mean radiation exposure dose at measured points was 34.46 ± 48.40 μGy without curtains, and 9.67 ± 4.53 μGy with curtains, exhibiting 71.94% reduction (p = 0.000). The use of lead shielding curtains significantly reduced scattered radiation at 0.5 m, 1.0 m, and 1.5 m from CT gantry, with percent reduction of 84.8%, 58.0% and 35.5%, respectively (p = 0.000, 0.000, 0.002). The percent reduction in the diagonal (+45°, -45°) and vertical forward (0°) directions were 86.3%, 83.1%, and 77.7%, respectively, and were statistically significant (p = 0.029, 0.020, 0.041). Shielding with lead curtains suggests an easy and effective method for reducing patient exposure to radiation in extremity CBCT imaging. Advances in knowledge: Lead shielding curtains are an effective technique to reduce scattered radiation dose in dedicated extremity CBCT, with higher dose reduction closer to the gantry opening.
    No preview · Article · Mar 2015 · The British journal of radiology

Publication Stats

1k Citations
205.97 Total Impact Points

Institutions

  • 2003-2016
    • Wonkwang University
      • • Institute for Radiological Imaging Science
      • • Department of Medicine
      Riri, Jeollabuk-do, South Korea
  • 2006-2010
    • Wonkwang University School of Medicine and Hospital
      Riri, North Jeolla, South Korea
    • Chubu University
      • Department of Mechanical Engineering
      Касугай, Aichi, Japan