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Gwangju, South Korea

Chonnam National University is a South Korean university located in the metropolitan city of Gwangju which lies in the middle of South Jeolla or Jeonnam province, for which the school is named in the Southwest of the country. The university was formally established in January, 1952 through the union of Gwangju Medical College, Gwangju Agricultural College, Mokpo Commerce College, and Daeseong College. It currently consists of 59 academic departments in 19 colleges and 11 graduate programs. University attached facilities are the University Library, Museum, Health Service Center, Agro-Bioindustry Technical Support Center, Animal Hospital, Language Education Center, School of Lifelong Education, and University Computing Center. In March 2006, Yeosu National University merged with Chonnam National University to become a satellite campus.Chonnam National University used to be generally regarded as one of the five major national universities of South Korea together with Seoul National University, Pusan National University, Kyungpook National University, and Chungnam National University. Now the number of the key national universities has been expanded into ten. CNU is also recognized as one of the best performers in government supported HRD projects. Research expenses of CNU ranks 13th nationally. Moreover, the number of High-ranking public officials ranked 11th. In addition, 26 alumni passed the Second Round of the 51st national bar exam, which is the biggest since the CNU Law School was established. Wikipedia.


Kim J.W.,Chonnam National University
Korean journal of radiology : official journal of the Korean Radiological Society | Year: 2012

The purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC. Pre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearson's correlation analysis was used to correlate CT perfusion parameters with MVD. In 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD. BF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs. However, perfusion CT is limited in distinguishing well differentiated and poorly differentiated CRCs. Pre-operative perfusion CT does not reflect the MVD of CRCs.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The PdII ion in the title complex, [PdI2(C 14H10N4)], is four-coordinated in a slightly distorted square-planar environment by the two pyridine N atoms of the chelating 2,3-di-2-pyridyl-pyrazine (dpp) ligand and two iodide anions. In the crystal, the pyridine rings are considerably inclined to the least-squares plane of the PdI2N2 unit [maximum deviation = 0.090 (2) Å], making dihedral angles of 65.0 (2) and 66.6 (2)°. The pyrazine ring is perpendicular to the unit plane, with a dihedral angle of 89.9 (2)°. The complex molecules are connected by C - H⋯I hydrogen bonds, forming a helical chain along the b axis. © Kwang Ha 2011.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The PdII ion in the title complex, [PdCl2(C 14H10N4)], has a slightly distorted square-planar environment defined by the two pyridine N atoms of the chelating 2,3-di-2-pyridylpyrazine ligand and two chloride anions. The pyridine rings are considerably inclined to the least-squares plane of the PdCl2N 2 unit [maximum deviation = 0.073 (1) Å], with dihedral angles of 64.19 (9) and 66.55 (9)°. The pyrazine ring is almost perpendicular to this plane and the dihedral angle is 88.2 (1)°. Two independent intermolecular C - H⋯Cl hydrogen bonds, both involving the same Cl atom as a hydrogen-bond acceptor, give rise to chains running along the a and b axes, generating a layer structure extending parallel to (001). molecules are stacked in columns along the a axis. Along the b axis, successive molecules stack in opposite directions. © Kwang Ha 2011.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The Mn II ion in the title complex, [MnCl 2(C 18H 12N 6)], is fivecoordinated in a distorted squarepyramidal geometry by three N atoms of the tridentate 2,4,6-tri-2-pyridyl- 1,3,5-triazine ligand and two chloride anions. In the crystal, the pyridyl rings are located approximately parallel to their carrier triazine ring, making dihedral angles of 5.0 (1), 3.8 (1) and 3.2 (1)°. Intramolecular C - H⋯N hydrogen bonds are present. The complexes are stacked in columns along the c axis and linked by intermolecular C - H⋯Cl hydrogen bonds, forming onedimensional chains. In the column, intermolecular π-π interactions between the sixmembered rings are present, the shortest centroidcentroid distance being 3.623 (2) Å. The structure reported herein represents a monoclinic polymorph of the previously reported triclinic form [Ha (2010). Acta Cryst. E66, m262].


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The Pt II ion in the title complex, [PtBr 2(C 14H 10N 4)], is fourcoordinated in a distorted squareplanar environment by two N atoms of a chelating 2,3-di-2-pyridylpyrazine ligand and two bromide anions. In the crystal, the pyridyl ring coordinated to the Pt atom is inclined slightly to its carrier pyrazine ring [dihedral angle = 14.7 (2)°], whereas the uncoordinated pyridyl ring is inclined considerably to the pyrazine ring [dihedral angle = 51.9 (3)°]. The dihedral angle between the two pyridyl rings is 57.7 (3)°. Two complex molecules are assembled through intermolecular C - H⋯N hydrogen bonds, forming a dimertype species. Intramolecular C - H⋯Br and C - H⋯N hydrogen bonds are also present.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The PdII ion in the title complex, [PdBr2(C 14H10N4)], is four-coordinated in a slightly distorted square-planar environment by the two pyridine N atoms of the chelating 2,3-di-2-pyridyl-pyrazine (dpp) ligand and two bromide anions. The pyridine rings are considerably inclined to the least-squares plane of the PdBr 2N2 unit [maximum deviation = 0.080 (2) Å], making dihedral angles of 64.9 (1) and 66.4 (1)°. The pyrazine ring is perpendicular to the unit plane, with a dihedral angle of 89.0 (1)°. In the crystal, the complex molecules are stacked in columns along the a axis and connected by C-H⋯Br hydrogen bonds, forming a helical chain along the b axis.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C 6H 6Cl 2N 2OPd, monoclinic, P12 1/cl (no. 14), a = 6.1726(7) Å, b = 15.948(2) Å, c = 9.115(1) Å, β = 100.506(2)°, V = 882.2 Å 3, Z = 4, R gr(F) = 0.037, wR ref(F 2) = 0.099, T = 200 K. © by Oldenbourg Wissensehaftsverlag.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The asymmetric unit of the title complex, [PdCl2(C 11H9N)2], contains one half of a neutral PdII complex, with the complete mol-ecule generated by the application of a twofold rotation axis; the N - Pd - N atoms lie on the axis. The PdII ion has a trans-Cl2N2 square-planar coordination geometry defined by two N atoms from two 4-phenylpyridine ligands and two Cl- anions. In the refinement, the pyridine ring and the phenyl ring were found to be disordered over two sites with the siteoccupancy factors being 0.53 (2) and 0.51 (1), respectively, for the major components.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The asymmetric unit of the title compound, {[MnBr2(C 8H6N4)]·2H2O}n , contains one half of a repeat unit of the neutral linear coordination polymer and a solvent water molecule, with the MnII ion on a crystallographic twofold axis. In the polymer, inversion-related MnII ions are bridged by the bis-chelating 2,2′-bipyrimidine (bpym) ligands, thereby forming a chain structure along the c-axis direction, and are six-coordinated in a distorted cis-N4Br2 octa-hedral environment by four N atoms of twofold-related bpym ligands and twofold-related bromide anions. In the crystal, the complex polymers and solvent water molecules are linked by intermolecular O-H⋯Br and C-H⋯O hydrogen bonds, forming a two-dimensional layered structure extending parallel to the ac plane..


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C 22H 20Cl 2N 2OPt, monoclinic, C12/c1 (no. 15), a = 9.4199(5) Å, b = 23.687(1) Å, c = 8.8435(5) Å, β = 101.257(1)°, V= 1935.3 Å 3, Z = 4, R gt(F) = 0.026, wR reg(F 2) = 0.072, T= 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C8H26Mn2N4O18S 2, monoclinic, P121/c1 (no. 14), a = 8.1522(5) Å, b = 11.6765(7) Å, c = 11.9942(7) Å, β = 91.667(1)°, V= 1141.2 Å3, Z= 2, Rgt(F) = 0.036, wRref(F 2) = 0.104, T= 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

In the title compound, [MnBr(C10H9N3) 2(H2O)]Br, the MnII ion is six-coordinated in a considerably distorted cis-N4BrO octa-hedral environment defined by four N atoms of two chelating di-2-pyridyl-amine (dpa) ligands, one Br - anion and one O atom of a water ligand. As a result of the different trans effects of Br, N and O atoms, the Mn - N bond trans to the Br atom is slightly longer than the Mn - N bond trans to the N or O atoms. In the crystal, the dpa ligands are not planar, the dihedral angles between the two pyridine rings being 29.2 (4) and 28.2 (3)°. The complex cations and the Br- anions are linked by intermolecular O-H⋯Br and N-H⋯Br hydrogen bonds. intermolecular π-π interactions are present between the pyridine rings, with a centroid-centroid distance of 3.793 (4) Å..


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C 10H 9Cl 4N 3Pt, monoclinic, P2 1/m (no. 11), a = 6.7195(6) Å, b = 14.014(1) Å, c = 7.6712(7) Å, β = 114.863(2)°, V= 655.4 Å 3, Z= 2, R gt(F) = 0.026, wR ref(F 2) = 0.052, T=200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The MnII ion in the title complex, [MnBr2(C 18H12N6)], is five-coordinated in a distorted square-pyramidal geometry by three N atoms of the tridentate 2,4,6-tri-2-pyridyl-1,3,5-triazine (tptz) ligand and two bromide anions. In the crystal, the pyridyl rings coordinated to the Mn atom are inclined slightly to their carrier triazine ring [dihedral angles = 8.0 (3) and 7.5 (3)°], whereas the uncoordinated pyridyl ring is located approximately parallel to the triazine ring [dihedral angle = 3.7 (3)°]. The complexes are stacked in columns along the a axis and linked by intermolecular C-H⋯Br hydrogen bonds, forming chains. In the column, intermolecular π-π interactions between the six-membered rings are present, the shortest centroid-centroid distance being 3.750 (4) Å.


Zmijewski J.W.,University of Alabama at Birmingham | Banerjee S.,University of Alabama at Birmingham | Bae H.,University of Alabama at Birmingham | Bae H.,Chonnam National University | And 3 more authors.
Journal of Biological Chemistry | Year: 2010

Although metabolic conditions associated with an increased AMP/ATP ratio are primary factors in the activation of 5′-adenosine monophosphate- activated protein kinase (AMPK), a number of recent studies have shown that increased intracellular levels of reactive oxygen species can stimulate AMPK activity, even without a decrease in cellular levels of ATP. We found that exposure of recombinant AMPKαβγ complex or HEK 293 cells to H2O2 was associated with increased kinase activity and also resulted in oxidative modification of AMPK, including S-glutathionylation of the AMPKα and AMPKβ subunits. In experiments using C-terminal truncation mutants of AMPKα (amino acids 1-312), we found that mutation of cysteine 299 to alanine diminished the ability of H2O2 to induce kinase activation, and mutation of cysteine 304 to alanine totally abrogated the enhancing effect of H2O2 on kinase activity. Similar to the results obtained with H2O2-treated HEK 293 cells, activation and S-glutathionylation of the AMPKα subunit were present in the lungs of acatalasemic mice or mice treated with the catalase inhibitor aminotriazole, conditions in which intracellular steady state levels of H2O2 are increased. These results demonstrate that physiologically relevant concentrations of H2O2 can activate AMPK through oxidative modification of the AMPKα subunit. The present findings also imply that AMPK activation, in addition to being a response to alterations in intracellular metabolic pathways, is directly influenced by cellular redox status. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.


Aravindan V.,Nanyang Technological University | Lee Y.-S.,Chonnam National University | Madhavi S.,Nanyang Technological University
Advanced Energy Materials | Year: 2015

Research activities related to the development of negative electrodes for construction of high-performance Li-ion batteries (LIBs) with conventional cathodes such as LiCoO2, LiFePO4, and LiMn2O4 are described. The anode materials are classified in to three main categories, insertion, conversion, and alloying type, based on their reactivity with Li. Although numerous materials have been proposed (i.e., for half-cell assembly), few of them have reached commercial applications, apart from graphite, Li4Ti5O12, Si, and Sn-Co-C. This clearly demonstrates that full-cell studies are desperately needed rather than just characterizing materials in half-cell assemblies. Additionally, the performance of such anodes in practical Li-ion configurations (full-cell) is much more important than merely proposing materials for LIBs. Irreversible capacity loss, huge volume variation, unstable solid electrolyte interface layer formation, and poor cycleability are the main issues for conversion and alloy type anodes. This review addresses how best to circumvent the mentioned issues during the construction of Li-ion cells and the future prospects of such anodes are described in detail. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Woo J.S.,Kyung Hee University | Kim W.,Kyung Hee University | Ha S.J.,Kyung Hee University | Kim J.B.,Kyung Hee University | And 4 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2013

Objective-Experimental evidence suggests that exenatide, a glucagon-like peptide 1 receptor analogue, has significant cardiovascular protective effects in various conditions. We examined whether routine use of exenatide at the time of primary percutaneous coronary intervention would reduce infarct size in patients with ST-segment-elevation myocardial infarction. Approach and Results-Fifty-eight patients with ST-segment-elevation myocardial infarction and thrombolysis in myocardial infarction flow 0 were enrolled in the study and randomly assigned to receive either exenatide or placebo (saline) subcutaneously. Infarct size was assessed by measuring the release of creatine kinase-MB and troponin I during 72 hours and by performing cardiac magnetic resonance imaging at 1 month after infarction. Routine and speckle tracking echocardiography was performed at initial presentation and at 3 days and 6 months after primary percutaneous coronary intervention. The exenatide and control groups had similar results with respect to ischemia time, demographic characteristics, and ejection fraction before primary percutaneous coronary intervention. The releases of creatine kinase-MB and troponin I were significantly reduced in the exenatide group. In 58 patients evaluated with cardiac magnetic resonance, the absolute mass of delayed hyperenhancement was significantly reduced in the exenatide group as compared with the control group (12.8±11.7 versus 26.4±11.6 g; P<0.01). At 6 months, the exenatide group showed a significantly lower value of E/E′ with improved strain parameters. No significant adverse effects of exenatide administration were detected. Conclusions-In patients with ST-segment-elevation myocardial infarction, adjunctive exenatide therapy with primary percutaneous coronary intervention was associated with reduction of infarct size and improvement of subclinical left ventricular function. © 2013 American Heart Association, Inc.


Ham D.-H.,Chonnam National University
Cognition, Technology and Work | Year: 2015

This study is aimed at developing a new method for modelling work domain knowledge with the combined use of abstraction hierarchy (AH) and living systems theory (LST). AH has been widely used as a work domain knowledge representation framework in the field of cognitive systems engineering and human–computer interaction, and its usefulness has been proved in a range of work domains. However, its effective use still remains a challenging issue. In order to address this problem, this study firstly points out several issues that can be raised in the use of AH and then explains why and how LST can give concepts and principles helpful to resolve them. The proposed method offers a framework for how to combine AH and LST, particularly to identify functional knowledge at higher abstraction levels. It also offers a process for modelling the knowledge of a work domain based on the combined use of AH and LST. The use of the proposed method is exemplified by modelling the knowledge of a simplified secondary cooling system of nuclear power plants. The proposed method is a new approach to refining the concepts of AH and modelling the knowledge of a work domain that humans should interact. It is believed that it will be a useful tool for knowledge modellers in identifying and modelling the knowledge of a work domain in terms of its functional structure. However, it should be noted that its usefulness can be limited to technology-oriented engineering systems; it would not be easily applied to human activity-oriented systems. © 2015, Springer-Verlag London.


Kwon Y.-S.,Chonnam National University | Koh W.-J.,Sungkyunkwan University
Expert Opinion on Investigational Drugs | Year: 2016

Introduction: Tuberculosis (TB) is a major global health concern. And while there are treatments already on the market, there is a demand for new drugs that are effective and safe against Mycobacterium tuberculosis, which reduce the number of drugs and the duration of treatment in both drug-susceptible TB and multidrug-resistant TB (MDR-TB).Area covered: This review covers promising novel investigational TB drugs that are currently under development. Specifically, the authors review the efficacy of novel agents for the treatment of TB in preclinical, phase I and phase II clinical trials. The authors also review the safety and tolerability profiles of these drugs.Expert opinion: Bedaquiline and delamanid are the most promising novel drugs for the treatment of MDR-TB, each having high efficacy and tolerability. However, the best regimen for achieving better outcomes and reducing adverse drug reactions remains to be determined, with safety concerns regarding cardiac events due to QT prolongation still to be addressed. Pretomanid is a novel drug that potentially shortens the duration of treatment in both drug-susceptible and drug-resistant TB in combination with moxifloxacin and pyrazinamide. Linezolid shows marked efficacy in the treatment of MDR-TB and extensively drug-resistant TB (XDR-TB), but the drug is known to cause significant adverse drug reactions, including peripheral neuropathy, optic neuropathy and myelosuppression. These adverse reactions must be considered prior to prescribing long-term usage of this drug. © 2015 Taylor and Francis.


Kim H.-W.,Yonsei University | Gupta S.,Bhilai Institute of Technology | Koh J.,Chonnam National University
Information and Management | Year: 2011

Some social networking community service providers have earned revenue by selling digital items to their community members. We examined SNC member decisions to purchase digital items based on customer value theory. Six factors were extracted from three dimensions of customer value: functional, social, and emotional value. Our findings indicated that the effects of value on member purchase intentions were significant in terms of the emotional and social dimensions. Our results should help SNC providers by improving their sales of digital items. © 2011 Elsevier B.V. All rights reserved.


Suh H.N.,Chonnam National University | Han H.J.,Seoul National University
Journal of Cellular Physiology | Year: 2011

Adhesion of cells to extracellular matrix (ECM) influences vital aspects of anchorage-dependent cell behavior including survival, proliferation, and differentiation. However, the role of collagen I in mouse embryonic stem cells (mESCs) is not well-known. Therefore, in the present study we examined the effect of collagen I on mESC self-renewal and related signal pathways. Collagen I (10μg/ml) maintained mESCs in an undifferentiated state (Nanog, OCT4, and SSEA-1) and did not affect differentiation (GATA4, Tbx5, Fgf5, and Cdx2) in the presence of leukemia inhibitory factor (LIF). Treatment with collagen I bound both α2β1 integrin and discoidin domain receptor 1 (DDR1), and stimulated intracellular signaling pathways. Collagen I-bound α2β1 integrin increased integrin-linked kinase (ILK) phosphorylation, cleaved Notch protein expression in the nuclear fraction, and Gli-1 mRNA expression. In addition, collagen I-bound DDR1 increased GTP-bound Ras, phosphoinositide 3-kinase (PI3K) p85α catalytic subunit protein expression, and Akt and ERK phosphorylation. Importantly, collagen I increased Bmi-1 protein expression in the nucleus which was blocked by small interfering RNA (siRNA) specific for Gli-1 and ERK, showing that parallel pathways of integrins and DDR1 merge at Bmi-1. Furthermore, collagen I-induced p16 decrease and p-Rb increase were reversed by Bmi-1-specific siRNA. Moreover, Bmi-1 silencing abolished the collagen I-induced increase of proliferation indices and undifferentiation markers. These results indicate that collagen I stimulates the self-renewal of mESCs mediated by Bmi-1 through α2β1 integrin-dependent ILK, Notch, Gli-1, and DDR1-dependent Ras, PI3K/Akt, and ERK. © 2011 Wiley-Liss, Inc.


Pulse-amplitude modulated (PAM) fluorometry allows instantaneous estimates of photosynthetic rates, but may well produce variable measurements of photosynthetic activity depending on time of day, recent light history, internal fluctuations, and environmental variability. To investigate this, we compare estimates of diurnal variability in relative photosynthetic performance for the giant kelp, Macrocystis pyrifera (L.) C. Agardh, obtained from PAM fluorometry at three depths during 3 days characterized by different light conditions, and for two different blade ages. Sampling in the mid morning, late morning, early afternoon and late afternoon, we examined diurnal changes in relative photosynthetic performance in meristematic tissue and older blades occurring near the bottom, in the mid water, and at the water surface. Measures of maximum relative electron transport rates (rETRmax), minimum saturating irradiance (Ek), photosynthetic efficiency (α) and maximum quantum yield (Fv/Fm) show that giant kelp blades in the mid water and near the bottom exhibit little to no photosynthetic changes during the day. Near the surface, however, blades exhibit photosynthetic characteristics similar to light-adapted species in that they begin the day acclimated to low light, acclimate to increasing irradiance during the day, and end the day acclimated to low light. Consequently, while estimates of rETRmax were highest during the midday for all sample depths and days, they were also always highest near the surface for both old blades (112.16 ± 8.7, 98.6 ± 14.7, 70.16 ± 5.7) and meristematic tissue (109.0 ± 9.0, 86.9 ± 1.9, 59.2 ± 11.6, surface, mid water and bottom, respectively). Similar patterns were observed for Ek for both old blades (169.2 ± 5.4, 88.0 ± 11.2, 83.8 ± 5.2) and meristematic tissue (138.4 ± 11.5, 96.6 ± 4.69, 68.4 ± 10.6). In contrast, estimates of Fv/Fm were lowest near the surface during the midday for both old blades (0.6 ± 0.02, 0.73 ± 0.69, 0.75 ± 0.01) and meristematic tissue (0.58 ± 0.02, 0.69 ± 0.05, 0.74 ± 0.01, surface, mid water and bottom, respectively). These patterns coincided with similar patterns in ambient light, which was most variable and reached its greatest values near the surface during the midday. © 2009 Elsevier B.V. All rights reserved.


Lee Y.,Chonnam National University
Journal of Physiological Anthropology | Year: 2015

Background: Anthropometric surveys devised by each country attempt to fulfill the requirements of the manufacturers, designers, and human welfare device production, providing them with data and tools and allowing them to face both the internal and export markets. To this end, national anthropometric data collections and comparisons including three-dimensional information, together with comparison of these data among countries, are conducted at both the domestic and global levels. Methods: The anthropometric data of the Korean population measured in 2013 (Korean Agency for Technology and Standard (KATS) 2013 data) and the data collected from 2010 (KATS 2010 data) that was conducted on 710 males between the ages of 13 and 18years were analyzed in this section to obtain information on Korean boy's physical features and growth. Results: The mean height increased about 5cm from 13 to 14years which shows the early fast maturing somatotype. Also, the mean height of boys aged from 15 to 16 increased about 1 to 2cm. For the results of body proportion rate index against height, they show 0.93, 0.81, 0.38, 0.99, and 0.26 times the height in eye height, shoulder height, fingertip height, and span and maximum shoulder breadth, respectively, in 16-year-old boys. For the body mass index, the weight is increased from the age of 16years. Conclusions: There are several studies that cover growth features of the entire range from birth to maturity, and they have reported the comparison of the growth patterns among Europeans. Even though such researches have been made, as for the industry, the human modeling tools based on the anthropometric data and morphological features that cover all the countries should be developed for well-fit garments and other human-oriented design process. © 2015 Lee; licensee BioMed Central.


The numerical conditions to generate high-purity {pipe}1 >, {pipe}2 >, and {pipe}1 > + re iψ{pipe}2 > states were found from the explicit form of the probability amplitudes for two cascade-placed beam splitters with one squeezed state input and two coherent state inputs. The expected theoretical signal-tonoise ratio is more than 1000. Controlling the amplitudes and the phases of two coherent beams, as well as the transmittances of two beam splitters, allow various quantum states to be manipulated with a high signal-to-noise ratio. High-purity nonclassical states are expected to be a key element in quantum information science. © 2014 The Korean Physical Society.


Aravindan V.,Nanyang Technological University | Sundaramurthy J.,Ngee Ann Polytechnic | Suresh Kumar P.,Ngee Ann Polytechnic | Lee Y.-S.,Chonnam National University | And 2 more authors.
Chemical Communications | Year: 2015

In the present review, we describe the development of a high energy density LIB fabricated with all 1D nanofibers as the anode and cathode, as well as a separator-cum-electrolyte prepared by an electrospinning technique without compromising the power capability and cycle life. Such a unique assembly certainly enables realizing the advantages of using 1D nanostructures in practical LIBs, irrespective of the anode or cathode in the presence of gelled polyvinylidene fluoride-co-hexafluoropropylene as the separator-cum-electrolyte. Outstanding cycling profiles with high power densities were noted for all the configurations evaluated. This excellent performance opens up new avenues for the development of high performance Li-ion power packs with a long cycle life and high energy and power densities to drive zero emission transportation applications in the near future, and opens up new research activities in this field as well. © The Royal Society of Chemistry 2015.


Chang H.-S.,Chonnam National University | Kim J.-W.,Gangneung - Wonju National University
Operative Dentistry | Year: 2014

The purpose of this study was to investigate whether dentin-layer thickness of resin overlays could affect the early hardness and shear bond strength of dual-cure resin cement (DCRC, RelyX ARC) after light curing with light curing units (LCUs) of various power densities: Optilux 360 (360), Elipar Freelight 2 (FL2), and Elipar S10 (S10). Resin overlays were fabricated using an indirect composite resin (Sinfony) with a dentin layer, an enamel layer, and a translucent layer of 0.5 mm thickness each (0.5-0.5-0.5) or of 0.2 mm, 0.5 mm, and 0.8 mm thickness (0.2-0.5-0.8), respectively. The DCRC was light cured for 40 seconds through the overlays, and surface hardness and shear bond strength to bovine dentin were tested 10 minutes after the start of light curing. Surface hardness was higher when the DCRC was light cured through the 0.2-0.5-0.8 combination than when the DCRC was light cured through the 0.5-0.5-0.5 combination with all LCUs. The ratio of upper surface hardness of DCRC light cured through resin overlays relative to the upper surface hardness of DCRC light cured directly was more than 90% only when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination. The shear bond strength value was higher when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination than when light cured with S10 through the 0.5-0.5-0.5 combination. This study indicates that reducing the dentin-layer thickness while increasing the translucent-layer thickness of resin inlays can increase the photopolymerization of DCRC, thereby increasing the early bond strength of resin inlays to dentin. ©Operative Dentistry, 2014.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C18H16Br2MnN6O2, monoclinic, P21/n (no. 14), a = 8.7713(4) Å, b = 11.9086(5) Å, c = 20.0404(9) Å, β = 97.333(1)°, V = 2076.2 Å3, Z = 4, Rgt(F) = 0.040, wRref(F 2) = 0.103, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C8H6Br2N4Pt, monoclinic, P121/c1 (no. 14), a = 15.214(1) Å, b = 21.326(2) Å, c = 6.9479(6) Å, β = 102.160(2)°, V = 2203.6 Å3, Z = 8, Rgt(F) = 0.043, wRrefF2) = 0.092, T=200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2011

C12H8ClN3O2Pt, orthorhombic, Pbca (no. 61), a = 14.1952(7) Å, b = 7.4719(4) Å, c = 22.630(1) Å, V= 2400.3 Å3, Z = 8, Rgt(F) = 0.034, wRref(F2) = 0.079, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Choi S.M.,Chonnam National University
Leprosy review | Year: 2012

Restless legs syndrome (RLS) is one of the most commonly encountered sleep disorders. The prevalence of RLS and its association'with leprosy have not previously been elucidated. The aims of this study were to investigate the prevalence of RLS in people affected by leprosy and to determine the presence and amount of sleep disruption in leprosy affected people with RLS. Each leprosy-affected person was matched to two healthy controls for age and sex. A total of 236 leprosy-affected people who lived in Sorokdo and 472 healthy control subjects who lived in Namwon were included in this study. A diagnosis of RLS and a severity assessment were made using the criteria described by the International Restless Legs Syndrome Study Group. The prevalence of RLS was significantly higher in people affected by leprosy (60/236; 25.4%) than in controls (42/472; 8.8%). Pittsburgh Sleep Quality Index (PSQI) global score was higher in leprosy-affected people than in controls. No significant difference was found between leprosy-affected people and controls with regard to the severity of RLS. Leprosy-affected people with RLS had a poorer sleep quality (higher PSQI global score) than those without RLS, but the Geriatric Depression Scale was not different between leprosy-affected people with RLS and those without RLS. The frequency of RLS among leprosy-affected people was significantly higher than that of RLS in the general population. Leprosy-affected people should be examined for RLS and treatment for RLS can potentially improve sleep.


Kang B.,Chonnam National University
Journal of Applied Fluid Mechanics | Year: 2016

This paper experimentally studied the dynamic behavior of a droplet impacting upon a liquid film, by investigating the effects of the droplet velocity and thickness of the liquid film on the impact behavior of the droplet. The formation of the crown, central jet, and disintegrating droplet from the central jet were visualized by time-delay photography. The time evolutions of the diameter and height of the crown and the height of the central jet were obtained, and the size of the disintegrating droplet from the central jet was measured. The crown diameter and the central jet height were mostly affected by the droplet velocity and the thickness of the liquid film, respectively, while the crown height was influenced by both the droplet velocity and the thickness of the liquid film. The diameter and height of the crown were higher for the case of the faster impacting droplet and thinner liquid film. On the other hand, the height of the central jet was higher for the case of the faster impacting droplet and thicker liquid film. The size of the disintegrating droplet from the central jet heavily depends on the velocity of the impacting droplet. Namely, a larger droplet is produced by a faster impacting droplet.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The asymmetric unit of the title compound, [MnI(C 8H 6N 4) 2(H 2O)]I·2H 2O, contains a cationic Mn II complex, an I - anion and two solvent water molecules. In the complex, the Mn II ion is six-coordinated in a considerably distorted octa-hedral environment defined by four N atoms of the two chelating 2,2′-bipyrimidine (bpym) ligands, one I - anion and one O atom of a water ligand. As a result of the different trans effects of the I and O atoms, the Mn-N bond trans to the I atom is slightly longer than the Mn-N bond trans to the O atom. The dihedral angle between the least-squares planes of the two bpym ligands [maximum deviation = 0.088 (4) Å] is 76.48 (6)°. In the crystal, the complex cation, the anion and the solvent water molecules are linked by intermolecular O-H⋯O, O-H⋯I and O-H⋯N hydrogen bonds.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The asymmetric unit of the title compound, [MnI(C 8H 6N 4) 2 -(H 2O)] I·H 2O, consists of a cationic Mn II complex, an I - anion and a solvent water molecule. In the complex, the Mn II ion is six-coordinated in a distorted octa-hedral environment defined by four N atoms of the two chelating 2,2′-bipyrimidine (bpym) ligands, one I - anion and one O atom of a water ligand. The dihedral angle between the least-squares planes of the two bpym ligands [maximum deviation = 0.092 (7) Å] is 79.9 (1)°. In the crystal, the complex, anion and solvent water molecule are linked by intermolecular O-H⋯O, O-H⋯I and O-H⋯N hydrogen bonds.


Chung K.-H.,Chonnam National University
Energy | Year: 2010

Hydrogen storage on microporous zeolites was examined using a high pressure dose of hydrogen at 30 °C. The roles of the framework structure, surface area, and pore volume of the zeolites on hydrogen adsorption were investigated. The largest hydrogen storage was obtained on the ultra stable Y (USY) zeolite (0.4 wt%). The hydrogen adsorption isotherms on the zeolites reached a maximum after a hydrogen pressure of 50 bar. The amount of hydrogen adsorption on Mordenite (MOR) zeolites increased with increasing Si/Al molar ratio, which was achieved by dealumination. The amount of hydrogen adsorption increased linearly with increasing pore volume of the zeolites. The hydrogen adsorption behavior was found to be dependent mainly on the pore volume of the zeolites. © 2010 Elsevier Ltd. All rights reserved.


Wang X.-L.,Chongqing University of Technology | Oh I.-K.,Korea Advanced Institute of Science and Technology | Lee S.,Chonnam National University
Sensors and Actuators, B: Chemical | Year: 2010

Based on a crosslinked ionic networking membrane of sulfonated poly(arylenethioethersulfone) copolymer (SPTES) and poly(vinyl alcohol) (PVA), a novel biomimetic artificial muscle with electrically driven bending deformation was developed. Sulfonated endcapped poly(arylenethioethersulfone) copolymer (SPTES) was synthesized through direct copolymerization of sulfonated monomers and poly(vinyl alcohol) (PVA) was crosslinked with SPTES by the dehydration method. The crosslinking reaction and molecular interactions between PVA and SPTES were observed in the FT-IR spectra of the PVA/SPTES ionic networking membrane. In comparison with the Nafion membrane, the crosslinked PVA/SPTES membrane shows much higher proton conductivity and ionic exchangeable capacity that are main factors influencing the actuation performance. Electroactive PVA/SPTES actuators show much larger bending deformation under step inputs without straightening-back relaxation and harmonic responses under sinusoidal excitations in a wide frequency band. © 2010 Published by Elsevier B.V.


Trivedi C.M.,University of Pennsylvania | Zhu W.,University of Pennsylvania | Wang Q.,University of Pennsylvania | Jia C.,University of Pennsylvania | And 4 more authors.
Developmental Cell | Year: 2010

Regulation of chromatin structure via histone modification has recently received intense attention. Here, we demonstrate that the chromatin-modifying enzyme histone deacetylase 2 (Hdac2) functions with a small homeodomain factor, Hopx, to mediate deacetylation of Gata4, which is expressed by cardiac progenitor cells and plays critical roles in the regulation of cardiogenesis. In the absence of Hopx and Hdac2 in mouse embryos, Gata4 hyperacetylation is associated with a marked increase in cardiac myocyte proliferation, upregulation of Gata4 target genes, and perinatal lethality. Hdac2 physically interacts with Gata4, and this interaction is stabilized by Hopx. The ability of Gata4 to transactivate cell cycle genes is impaired by Hopx/Hdac2-mediated deacetylation, and this effect is abrogated by loss of Hdac2-Gata4 interaction. These results suggest that Gata4 is a nonhistone target of Hdac2-mediated deacetylation and that Hdac2, Hopx, and Gata4 coordinately regulate cardiac myocyte proliferation during embryonic development. © 2010 Elsevier Inc.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The asymmetric unit of the title compound, [MnBr2(C 8H6N4)2]·CH 3NO2, contains one half of a neutral MnII complex and one half of a nitromethane solvent molecule, the complete molecules being generated by the application of twofold symmetry. In the complex, the MnII ion has a distorted cis-Br2N4 octa-hedral coordination geometry defined by four N atoms of the two chelating 2,2′-bipyrimidine ligands and two Br- ions. There are intra- and intermolecular C - H⋯Br and C - H⋯N contacts.


Cha K.S.,Chonbuk National University | Bae J.H.,Chonnam National University
Energy Policy | Year: 2011

This study investigates the impacts of high international oil prices on the bioethanol and corn markets in the US. Between 2007 and 2008, the prices of major grain crops had increased sharply, reflecting the rise in international oil prices. These dual price shocks had caused substantial harm to the global economy. Employing a structural vector auto-regression model (SVAR), we analyze how increases in international oil prices could impact the prices of and demand for corn, which is used as a major bioethanol feedstock in the US. The results indicate that an increase in the oil price would increase bioethanol demand for corn and corn prices in the short run and that corn prices would stabilize in the long run as corn exports and feedstock demand for corn decline. Consequently, policies supporting biofuels should encourage the use of bioethanol co-products for feed and the development of marginal land to mitigate increases in the feedstock price. © 2010 Elsevier Ltd.


Jang W.S.,Chonnam National University
International braz j urol : official journal of the Brazilian Society of Urology | Year: 2013

Endoscopic urethrotomy is an alternative method in treatment of urethral stricture. However, it have high recurrence rate because of the remained fibrotic tissue. Removal of the fibrotic tissue can maintain the patency of the urethral lumen after the procedure. We report the therapeutic efficacy of our initial experience using pediatric resectoscope for treating anterior urethral stricture in 16 cases. From January 2009 to April 2011, transurethral resection with pediatric resectoscope was primarily performed on 16 patients with anterior urethral stricture. Retrograde urethrography, uroflowmetry, postvoid residual volume, IPSS score and QoL score were performed preoperatively. We used 11.5Fr pediatric resectoscope (Wolf) and monopolar electrosurgical generator. The stricture was incised under vision at the 12 o'clock location or the site of maximum scar tissue or narrowing in asymmetric strictures for working space. After incision, transurethral resection with pediatric resectoscope was performed to all scar tissues. Monopolar cutting current was set on 45 watt and coagulation current was set on 30 watt, fulgurate mode. Postoperatively, drainage of the bladder was performed for 7 days using an 18F latex catheter. Patients were followed up by IPSS score, QoL score, uroflowmetry and postvoid residual volume. Successful results without recurrence were achieved in 11 of 16 patients. Postoperative urethral dilation had been performed average 2.4 times (0~6 times). When we classified the results by etiology, the number of successful results in strictures with a trauma, iatrogenic, or unknown cause was 5 (7/11), 3 (3/4) and 1 (1/1), respectively. In 5 patients who failed treatment, we repeated transurethral resection with pediatric resectoscope in 1 patient, and periodic urethral dilation in 4 patients. No operative complications occurred in any patients. Transurethral resection with pediatric resectoscope is an effective therapeutic method for anterior urethral stricture. More long-term follow-up and large scale studies are needed to confirm the efficacy of this procedure.


Sethna F.,Michigan State University | Moon C.,Chonnam National University | Wang H.,Michigan State University
Neurochemical Research | Year: 2014

Fragile X syndrome (FXS) is caused by mutations in the fragile X mental retardation 1 (FMR1 ) gene. Most FXS cases occur due to the expansion of the CGG trinucleotide repeats in the 5′ un-translated region of FMR1, which leads to hypermethylation and in turn silences the expression of FMRP (fragile X mental retardation protein). Numerous studies have demonstrated that FMRP interacts with both coding and non-coding RNAs and represses protein synthesis at dendritic and synaptic locations. In the absence of FMRP, the basal protein translation is enhanced and not responsive to neuronal stimulation. The altered protein translation may contribute to functional abnormalities in certain aspects of synaptic plasticity and intracellular signaling triggered by Gq-coupled receptors. This review focuses on the current understanding of FMRP function and potential therapeutic strategies that are mainly based on the manipulation of FMRP targets and knowledge gained from FXS pathophysiology. © Springer Science+Business Media 2013.


Ahn J.K.,Chonnam National University
Ocular Immunology and Inflammation | Year: 2010

Purposes: To investigate morphologic changes in anterior segments based on inflammatory phases of Vogt-Koyanagi-Harada (VKH). Methods: The author recruited 76 consecutive eyes of 38 patients with initial-onset VKH and 52 eyes of 26 patients with recurrent VKH. Morphologic changes in anterior segments were measured by ultrasound biomicroscopy (UBM). UBM parameters and intraocular pressure (IOP) were compared between two groups. Results: Ciliary thickness and area significantly increased in the recurrent group compared with the initial-onset group. Twelve patients (31%) in the initial-onset group showed supraciliary effusions, but no patients in the recurrent group had supraciliary effusions. Angle opening and anterior chamber depth were significantly decreased in the initial-onset group compared with the recurrent group. High IOP > 30 mmHg was found in 7 patients with initial-onset disease, while low IOP < 10 mmHg was detected in 6 patients with recurrent disease. Conclusions: The results indicate that morphologic changes associated with IOP alterations depend on inflammatory phases of VKH disease. © 2010 Informa Healthcare USA, Inc.


Kim D.,Gwangju Institute of Science and Technology | Jeong Y.Y.,Chonnam National University | Jon S.,Gwangju Institute of Science and Technology
ACS Nano | Year: 2010

Computed tomography (CT) is one of the most useful diagnostic tools among commonly used biomedical imaging techniques, which also include magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasound. However, currently available CT contrast agents, which are based on small iodinated molecules, possess a number of limitations, including a lack of targeted molecular imaging, short imaging time, and renal toxicity. Here, we report a multifunctional nanoparticle for targeted molecular CT imaging and therapy of prostate cancer. By functionalizing the surface of gold nanoparticles (GNPs) with a prostate-specific membrane antigen (PSMA) RNA aptamer that binds to PSMA, we established a targeted molecular CT imaging system capable of specific imaging of prostate cancer cells that express the PSMA protein. The resulting PSMA aptamer-conjugated GNP showed more than 4-fold greater CT intensity for a targeted LNCaP cell than that of a nontargeted PC3 cell. Furthermore, the PSMA aptamer-conjugated GNPs after loading of doxorubicin were significantly more potent against targeted LNCaP cells than against nontargeted PC3 cells. © 2010 American Chemical Society.


Aravindan V.,Nanyang Technological University | Gnanaraj J.,Yardney Technical Products, Inc. | Lee Y.-S.,Chonnam National University | Madhavi S.,Nanyang Technological University
Chemical Reviews | Year: 2014

Apart from the mentioned applications, wind power generation, uninterruptible power sources, voltage sag compensation, photovoltaic power generation, CT and MRI scanners, and energy recovery systems in industrial machineries are worth mentioning. Carbonaceous materials are favored as EDLC components due to their high specific surface area, relatively low cost, chemical stability in solutions irrespective of the pH value, ease of synthesis protocols with tailored pore size distribution and its amphoteric nature that allows rich electrochemical properties from donor to acceptor state, and a wide range of operating temperatures. The combination reactions enable one to achieve higher energy density and specific capacitance than the EDLC counterpart. Conducting polymers and transition metal oxides are the perfect examples for pseudocapacitive materials.


Lee S.A.,Chonnam National University | Song K.,Arkansas State University
International Journal of Computer-Supported Collaborative Learning | Year: 2016

This discourse analytic study explored the interconnection between resistance and perspectival understanding when students negotiated and constructed understandings in computer-mediated discussions in a graduate level course on the psychology of learning. Findings showed that resistance expressions often accompanied perspectival understanding as students elaborated on ideas from authors of course readings or peers. Furthermore, perspectival understanding was achieved both on the individual level and the group level as students showed resistance to the authors of course readings, their peers, and educational issues. These findings suggested that resistance played a role as a constructive discourse tool in a collaborative learning environment in which students made meaning of scholarly texts. This study is of importance in understanding the integral role of resistance in perspectival understanding in computer-mediated classroom discussions that has been rarely explored in empirical educational research. © 2016, International Society of the Learning Sciences, Inc.


Zheng F.,St Jude Childrens Research Hospital | Zhou X.,Nanjing Medical University | Moon C.,Chonnam National University | Wang H.,Michigan State University
International Journal of Physiology, Pathophysiology and Pharmacology | Year: 2012

Brain-derived neurotrophic factor (BDNF) plays critical roles in many aspects of brain functions, including cell survival, differentiation, development, learning and memory. Aberrant BDNF expression has also been implicated in numerous neurological disorders. Thus, significant effort has been made to understand how BDNF transcription as well as translation is regulated. Interestingly, the BDNF gene structure suggests that multiple promoters control its transcription, leading to the existence of distinct mRNA species. Further, the long-and short-tail of the 3′ un-translated region may dictate different sub-cellular BDNF mRNA targeting and translational responses following neuronal stimulation. This review aims to summarize the main findings that demonstrate how neuronal activities specifically up-regulate the transcription and translation of unique BDNF transcripts. We also discuss some of the recent reports that emphasize the epigenetic regulation of BDNF transcription.


Choi Y.,Pohang University of Science and Technology | Lee Y.,Pohang University of Science and Technology | Kim S.Y.,Chonnam National University | Hwang J.-U.,Pohang University of Science and Technology
Plant, Cell and Environment | Year: 2013

Auxin and abscisic acid (ABA) modulate numerous aspects of plant development together, mostly in opposite directions, suggesting that extensive crosstalk occurs between the signalling pathways of the two hormones. However, little is known about the nature of this crosstalk. We demonstrate that ROP-interactive CRIB motif-containing protein 1 (RIC1) is involved in the interaction between auxin- and ABA-regulated root growth and lateral root formation. RIC1 expression is highly induced by both hormones, and expressed in the roots of young seedlings. Whereas auxin-responsive gene induction and the effect of auxin on root growth and lateral root formation were suppressed in the ric1 knockout, ABA-responsive gene induction and the effect of ABA on seed germination, root growth and lateral root formation were potentiated. Thus, RIC1 positively regulates auxin responses, but negatively regulates ABA responses. Together, our results suggest that RIC1 is a component of the intricate signalling network that underlies auxin and ABA crosstalk. © 2012 Blackwell Publishing Ltd.


Ryu H.S.,Chonnam National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2010

Acute hepatitis A was recently significant increased among women with gestational age in Korea. However, the clinical course and gestational complications have not been fully elucidated in pregnant patients with acute hepatitis A. We evaluated the clinical impact of acute HAV infection in pregnancy. Twelve pregnant women out of 85 female patients with acute hepatitis A during 6 years were retrospectively reviewed. Results: The median age of the pregnant group was 26.5 years old. The number of patient with acute hepatitis A were 5 cases in the 1st trimester, 3 cases in the 2nd and 4 cases in the 3rd. 4 cases had significant gestational complications. One case experienced the abortion in 1st trimester and one fetal distress was noted in 3rd trimester. The latter case was delivered of a low birth weight infant (2,390 g) caused by premature rupture of membrane in 36 weeks of gestational age. Other two cases experienced premature contraction and they had been required tocolytic treatment. But, all mothers featured full recovery from HAV infection. Except one aborted fetus and one premature birth, Newborn babies were not affected by maternal hepatitis A. Acute HAV infection during pregnancy may be associated with the risk of gestational complications. HAV serology and vaccination for women with gestation age should be considered at high prevalence area of acute hepatitis A.


Noh H.-R.,Chonnam National University
Optics Express | Year: 2012

We present a theoretical study of lineshape in polarization spectroscopy for the 6S1/2-6P3/2-7S1/2 transition line in cesium atoms. A circularly polarized pump beam is tuned either to the lower or the upper transition line, while a linearly polarized probe beam is tuned to the other transition line. The polarization rotation of the probe beam is accurately calculated using a semi-classical density-matrix formalism taking into account all relaxation processes. © 2012 Optical Society of America.


Yang Y.,Chongqing University of Technology | Kang B.-S.,Chonnam National University
Optics and Lasers in Engineering | Year: 2011

A digital particle holographic system for measurements of spray fields is presented. A double exposure hologram recording system with a synchronization system for time control is established, resulting in digital holograms that can be quickly recorded. To process recorded holograms, the correlation coefficient method is used for focal plane determination of particles. To remove noise and improve the quality of holograms and reconstructed images, a Wiener filter is adopted. The two-threshold and image segmentation methods are used for binary image transformation. For particle pairing, the match probability method is adopted. The proposed system is applied to a spray field, and three-dimensional velocities and sizes of spray droplets are measured. Measurement results from the digital holographic system are compared to those made by laser instruments, which prove the feasibility of the proposed in-line digital particle holographic system as a good measurement tool for spray droplets. © 2011 Elsevier Ltd.


Lee H.-J.,Chonnam National University
Recent Patents on Chemical Engineering | Year: 2011

Electromembrane processes are considered to be one of the promising industrial applicable ones using an electrical potential as high energy-efficient processes. Their applications can be found in various fields such as water desalination, water and wastewater treatment, food industries, production of acids and bases, elimination of toxic components, regeneration of metal ions from industrial waste streams, ultra pure water production and etc. The electromembrane process integration with other processes has received more attention recently in the patents as well as published articles since it provides versatile tools for industrial separations, increasing process effectiveness by optimization of the utilization of electromembrane processes. A substantial number of industrial applications for the integration of electromembrane process can be found mainly in areas of chemical unit operations, pressure-driven membrane processes, and biochemical unit processes. This review presents the recent progress on electromembrane based integrations for industrial separations based on patents as well as some published articles. The patent search has been performed in different databases in which the patents can be searched and in most cases downloaded. The keywords such as "Electromembrane process, Integration, Separation, Purification, Electromembrane" were considered for the current patents on electromembrane based integrated/ hybrid processes. © 2011 Bentham Science Publishers.


Lee H.-J.,Chonnam National University | Hong M.-K.,Korea Environment Corporation | Moon S.-H.,Gwangju Institute of Science and Technology
Desalination | Year: 2012

Interests on the polarity reversal have increased to prevent or minimize membrane fouling and scaling during the operation of electromembrane processes. In this study, the influence of the operation conditions on the process efficiency was investigated in the electrodeionization reversal (EDIR) system with an electrodeionization with the polarity reversal. The removal efficiencies of divalent cations (Mg 2+ and Ca 2+) kept high value without scale formation on the membrane surface. Through the EDIR operation, the process performance was affected by polarity reversal periods, and the operating polarity reversal period was determined to 40min or shorter in this study.In the long term EDIR experiments with different cation exchange membranes, the homogeneous membranes showed marginally higher removal efficiency compared to the heterogeneous membrane. The scale powders and the surface of scaled membrane were analyzed using electron microscopes and it was observed that the scales formed as carbonate of divalent cations. The EDIR results showed the feasibility of the EDIR system for use in water softening process without significant scale formation even in a relatively high concentration. © 2011 Elsevier B.V..


Lim J.,Korea University | Choi H.-S.,Chonnam National University | Choi H.J.,Korea University
Journal of Neurochemistry | Year: 2015

The orphan nuclear receptor estrogen-related receptor gamma (ERRγ) is highly expressed in the nervous system during embryogenesis and in adult brains, but its physiological role in neuronal development remains unknown. In this study, we evaluated the relevance of ERRγ in regulating dopaminergic (DAergic) phenotype and the corresponding signaling pathway. We used retinoic acid (RA) to differentiate human neuroblastoma SH-SY5Y cells. RA induced neurite outgrowth of SH-SY5Y cells with an increase in DAergic neuron-like properties, including up-regulation of tyrosine hydroxylase, dopamine transporter, and vesicular monoamine transporter 2. ERRγ, but not ERRα, was up-regulated by RA, and participated in RA effect on SH-SY5Y cells. ERRγ over-expression enhanced mature DAergic neuronal phenotype with neurite outgrowth as with RA treatment; and RA-induced increase in DAergic phenotype was attenuated by silencing ERRγ expression. ERRγ appears to have a crucial role in morphological and functional regulation of cells that is selective for DAergic neurons. Polo-like kinase 2 was up-regulated in ERRγ-over-expressing SH-SY5Y cells, which was involved in phosphorylation of glycogen synthase kinase 3β and resulting downstream activation of nuclear factor of activated T cells. The likely involvement of ERRγ in regulating the DAergic neuronal phenotype makes this orphan nuclear receptor a novel target for understanding DAergic neuronal differentiation. © 2015 International Society for Neurochemistry.


Expression of Livin, a member of the inhibitors of apoptosis protein family, is associated with tumor development and progression. The aims of this study were to evaluate whether Livin affects oncogenic biological behavior of colorectal cancer cells, and to document the relationship between its expression and various clinicopathological parameters in colorectal cancer. We investigated the impact of Livin on tumor cell behavior by using the small interfering RNA and pcDNA3.1 vector in SW480 and DKO1 colorectal cancer cell lines. The expression of Livin was investigated by RT-PCR and immunohistochemistry in coloretcal cancer tissues. The apoptotic cells were visualized by TUNEL assay, and proliferative cells were visualized by Ki-67 antibody staining. Knockdown of Livin suppressed tumor cell migration and invasion in colorectal cancer cells. Knockdown of Livin induced the apoptosis by up-regulating of caspase-3, -7 and PARP activities and the cell cycle arrest by decreasing cyclin D1, cyclin D3, cyclin-dependent kinase 4 and 6, and by inducing p27 expression. The MAPK signaling cascades were significantly blocked by knockdown of Livin. In contrast, overexpression of Livin enhanced tumor cell migration and invasion, and inhibited the apoptosis and cell cycle arrest. The mean apoptotic index (AI) value of Livin positive tumors was significantly lower than AI of Livin negative tumors. However, there was no significant difference between Livin expression and Ki-67 labeling index (KI). Livin expression was significantly increased in colorectal cancer and metastatic lymph node tissues compared to normal colorectal mucosa and non-metastatic lymph node tissues and was associated with tumor stage, lymphovascular invasion, lymph node metastasis and poor survival. These results indicate that Livin is associated with tumor progression by increasing tumor cell motility and inhibiting apoptosis in colorectal cancer.


Ham D.-H.,Chonnam National University
Cognition, Technology and Work | Year: 2014

A great deal of study has been devoted to the problem of how to identify and categorize usability problems; however, there is still a lack of studies dealing with the problem of how to diagnose the causes of usability problems and how to feed them back into design process. The value of classifying usability problems can be enhanced when they are interpreted in connection with design process and activities. Thus, it is necessary to develop a systematic way of diagnosing usability problems in terms of design aspects and applying diagnosis results to improve design process and activities. With this issue in mind, this paper proposes a conceptual framework that supports a systematic classification and diagnosis of usability problems. This paper firstly reviews seven approaches to classifying usability problems. Then, we point out the needs of adopting a model-based approach to classifying and diagnosing usability problems and of developing a comprehensive framework guiding the use of model-based approaches. We then propose a conceptual framework that specifies how a model-based classification and diagnosis of usability problems should be conducted and suggests the combined use of three different types of models, each of which addresses context of use, design knowledge and design activities. Last, we explain how a sound classification scheme of usability problems can be systematically developed, and how the classification of usability problems can be connected to design process and activities on the basis of the framework. © 2013 Springer-Verlag London.


Bang Y.,Chonnam National University | Bang Y.,Asia Pacific Center for Theoretical Physics
New Journal of Physics | Year: 2014

The electron band around the M point in the compound, which is completely lifted up above the Fermi level for and hence its Fermi surface (FS) disappears, can still play the role of the main pairing resource by exchanging inter-band repulsive interaction with the main hole band (h1) around the point. This hidden electron band, which develops the superconducting order parameter (OP) but has no FS, displays a shadow gap feature which is easily detected by various experimental probes such as angle-resolved photoemission spectroscopy (ARPES) and tunneling measurements. We also show that the formation of the nodal gap with symmetry on another hole pocket (h2) around the point with a larger FS is stabilized due to the balance of the inter-band repulsive interactions from the main hole band (h1) with the OP , and the hidden electron band with the OP . © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.


Park S.H.,Chonnam National University | Lee C.S.,Hanyang University
Energy Conversion and Management | Year: 2014

From the perspectives of environmental conservation and energy security, dimethyl-ether (DME) is an attractive alternative to conventional diesel fuel for compression ignition (CI) engines. This review article deals with the application characteristics of DME in CI engines, including its fuel properties, spray and atomization characteristics, combustion performance, and exhaust emission characteristics. We also discuss the various technological problems associated with its application in actual engine systems and describe the field test results of developed DME-fueled vehicles. Combustion of DME fuel is associated with low NOx, HC, and CO emissions. In addition, PM emission of DME combustion is very low due to its molecular structure. Moreover, DME has superior atomization and vaporization characteristics than conventional diesel. A high exhaust gas recirculation (EGR) rate can be used in a DME engine to reduce NOx emission without any increase in soot emission, because DME combustion is essentially soot-free. To decrease NOx emission, engine after-treatment devices, such as lean NOx traps (LNTs), urea-selective catalytic reduction, and the combination of EGR and catalyst have been applied. To use DME fuel in automotive vehicles, injector design, fuel feed pump, and the high-pressure injection pump have to be modified, combustion system components, including sealing materials, have to be rigorously designed. To use DME fuel in the diesel vehicles, more research is required to enhance its calorific value and engine durability due to the low lubricity of DME, and methods to reduce NOx emission are also required. © 2014 Elsevier Ltd. All rights reserved.


Chae H.Z.,Chonnam National University | Oubrahim H.,U.S. National Institutes of Health | Park J.W.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases | Rhee S.G.,Ewha Womans University | Chock P.B.,U.S. National Institutes of Health
Antioxidants and Redox Signaling | Year: 2012

Reversible protein glutathionylation plays an important role in cellular regulation, signaling transduction, and antioxidant defense. This redox-sensitive mechanism is involved in regulating the functions of peroxiredoxins (Prxs), a family of ubiquitously expressed thiol-specific peroxidase enzymes. Glutathionylation of certain Prxs at their active-site cysteines not only provides reducing equivalents to support their peroxidase activity but also protects Prxs from irreversible hyperoxidation. Typical 2-Cys Prx also functions as a molecular chaperone when it exists as a decamer and/or higher molecular weight complexes. The hyperoxidized sulfinic derivative of 2-Cys Prx is reactivated by sulfiredoxin (Srx). In this review, the roles of glutathionylation in the regulation of Prxs are discussed with respect to their molecular structure and functions as antioxidants, molecular chaperones, and signal modulators. Recent Advances: Recent findings reveal that glutathionylation regulates the quaternary structure of Prx. Glutathionylation of Prx I at Cys 83 converts the decameric Prx to its dimers with the loss of chaperone activity. The findings that dimer/oligomer structure specific Prx I binding proteins, e.g., phosphatase and tensin homolog (PTEN) and mammalian Ste20-like kinase-1 (MST1), regulate cell cycle and apoptosis, respectively, suggest a possible link between glutathionylation and those signaling pathways. Critical Issues: Knowing how glutathionylation affects the interaction between Prx I and its nearly 20 known interacting proteins, e.g., PTEN and MST1 kinase, would reveal new insights on the physiological functions of Prx. Future Directions: In vitro studies reveal that Prx oligomerization is linked to its functional changes. However, in vivo dynamics, including the effect by glutathionylation, and its physiological significance remain to be investigated. © 2012, Mary Ann Liebert, Inc.


Choi H.J.,Chonnam National University
International Journal of Naval Architecture and Ocean Engineering | Year: 2015

In the present study, a hydrodynamic hull-form optimization algorithm for a container ship was presented in terms of the minimum wave-making resistance. Bell-shaped modification functions were developed to modify the original hull-form and a sequential quadratic programming algorithm was used as an optimizer. The wave-making re-sistance as an objective function was obtained by the Rankine source panel method in which non-linear free surface conditions and the trim and sinkage of the ship were fully taken into account. Numerical computation was performed to investigate the validity and effectiveness of the proposed hull-form modification algorithm for the container carrier. The computational results were validated by comparing them with the experimental data. © 2015, Int. J. Nav. Archit. Ocean Eng. All rights reserved.


Hong S.-H.,Inha University | Jang M.-S.,Inha University | Cho S.J.,Chonnam National University | Ahn W.-S.,Inha University
Chemical Communications | Year: 2014

Mesoporous chabazite ion-exchanged with Ca2+ was effective for CO2 capture at 20 bar and 473 K, whereas 13X as a support material enabled recyclable carbonation of ca. 8 wt% Mg(OH)2 approaching the theoretical maximum for CO2 capture with 10% H2O. © 2014 the Partner Organisations.


Moon H.S.,Pusan National University | Noh H.-R.,Chonnam National University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

The polarization dependence of double-resonance optical pumping (DROP) in the ladder-type electromagnetically induced transparency (EIT) of the 5S 1/2-5P3/2-5D5/2 transition of 87Rb atoms is studied. The transmittance spectra in the 5S1/2(F=2)-5P 3/2(F′=3)-5D5/2(F′ ′=2,3,4) transition were observed as caused by EIT, DROP, and saturation effects in the various polarization combinations between the probe and coupling lasers. The features of the double-structure transmittance spectra in the 5S1/2(F=2)-5P3/2(F′=3)-5D 5/2(F′′=4) cycling transition were attributed to the difference in saturation effect according to the transition routes between the Zeeman sublevels and the EIT according to the two-photon transition probability. © 2011 American Physical Society.


Lo P.-K.,University of South Carolina | Lee J.S.,Chonnam National University | Sukumar S.,Johns Hopkins University
Cellular Signalling | Year: 2012

We previously identified FOXF1 as a potential tumor suppressor gene with an essential role in preventing DNA rereplication to maintain genomic stability, which is frequently inactivated in breast cancer through the epigenetic mechanism. Here we further addressed the role of the p53-p21WAF1 checkpoint pathway in DNA rereplication induced by silencing of FOXF1. Knockdown of FOXF1 by small interference RNA (siRNA) rendered colorectal p53-null and p21WAF1-null HCT116 cancer cells more susceptible to rereplication and apoptosis than the wild-type parental cells. In parental HCT116 cells with a functional p53 checkpoint, the p53-p21WAF1 checkpoint pathway was activated upon FOXF1 knockdown, which was concurrent with suppression of the CDK2-Rb cascade and induction of G1 arrest. In contrast, these events were not observed in FOXF1-depleted HCT116-p53-/- and HCT116-p21-/- cells, indicating that the p53-dependent checkpoint function is vital for inhibiting CDK2 to induce G1 arrest and protect cells from rereplication. The pharmacologic inhibitor (caffeine) of ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3 related (ATR) protein kinases abolished activation of the p53-p21WAF1 pathway upon FOXF1 knockdown, suggesting that suppression of FOXF1 function triggered the ATM/ATR-mediated DNA damage response. Cosilencing of p53 by siRNA synergistically enhanced the effect of FOXF1 depletion on the stimulation of DNA rereplication and apoptosis in wild-type HCT116. Finally, we show that FOXF1 expression is predominantly silenced in breast and colorectal cancer cell lines with inactive p53. Our study demonstrated that the p53-p21WAF1 checkpoint pathway is an intrinsically protective mechanism to prevent DNA rereplication induced by silencing of FOXF1. © 2011 Elsevier Inc.


Lee J.S.,Seoul National University | Kwon O.S.,Seoul National University | Park S.J.,Seoul National University | Park E.Y.,Seoul National University | And 3 more authors.
ACS Nano | Year: 2011

Ultrafine metal-oxide-decorated hybrid carbon nanofibers (CNFs) were fabricated by a single-nozzle co-electrospinning process using a phase-separated mixed polymer composite solution and heat treatment. To decorate metal oxides on the CNF surface, core (PAN) and shell (PVP) structured nanofibers (NFs) were fabricated as starting materials. The core-shell NF structure was prepared by single-nozzle co-electrospinning because of the incompatibility of the two polymers. Ultrafine hybrid CNFs were then formed by decomposing the PVP phase, converting the metal precursors to metal oxide nanonodules, and transforming the PAN to CNFs of ca. 40 nm diameter during heat treatment. The decoration morphology of the metal oxide nanonodules could be controlled by precursor concentration in the PVP solution. These ultrafine hybrid CNFs were applied to a dimethyl methylphosphonate (DMMP) chemical sensor at room temperature with excellent sensitivity. The minimum detectable level (MDL) of hybrid CNFs was as low as 0.1 ppb, which is 10-100 times higher than for a chemical sensor based on carbon nanotubes. This is because the metal oxide nanonodules of hybrid CNFs increase the surface area and affinity to DMMP vapor. Our new synthetic methodology promises to be an effective approach to fabricating hybrid CNF/inorganic nanostructures for future sensing technologies. © 2011 American Chemical Society.


Kim B.-H.,Daegu University | Yang K.S.,Chonnam National University
Journal of Electroanalytical Chemistry | Year: 2014

Porous carbon nanofibers with SiOC/SiOSi group (Si/ACNF) mats are produced by incorporating tetraethyl orthosilicate (TEOS) into polyacrylonitrile (PAN) via electrospinning/activation, and their electrochemical properties as a supercapacitor electrode are investigated. The Si/ACNF exhibits a high surface area of up to 1386.91 m2 g-1 as result of the ultramicropore size distributions centered at approximately 0.8 nm and mesopore volume fraction up to 38%. The gravimetric capacitance of the Si/ACNF webs in an organic electrolyte is 91.95 F g-1, and the energy densities are 59.72-88.23 Wh kg-1 over the power density range of 1000-20,000 W kg-1. The electrochemical capacitance of a Si/ACNF electrode is closely related to the pore size distribution, surface area, and ionic accessibility of the electrode material, providing a large charge capacity and high rate capability. © 2013 Elsevier B.V. All rights reserved.


Lee W.-J.,University of Dundee | Wilkinson C.M.,University of Dundee | Hwang H.-S.,Chonnam National University
Journal of Forensic Sciences | Year: 2012

The utilization of 3D computerized systems has allowed more effective procedures for forensic facial reconstruction. Three 3D computerized facial reconstructions were produced using skull models from live adult Korean subjects to assess facial morphology prediction accuracy. The 3D skeletal and facial data were recorded from the subjects in an upright position using a cone-beam CT scanner. Shell-to-shell deviation maps were created using 3D surface comparison software, and the deviation errors between the reconstructed and target faces were measured. Results showed that 54%, 65%, and 77% of the three facial reconstruction surfaces had <2.5mm of error when compared to the relevant target face. The average error for each reconstruction was -0.46mm (SD=2.81) for A, -0.31mm (SD=2.40) for B, and -0.49mm (SD=2.16) for C. The facial features of the reconstructions demonstrated good levels of accuracy compared to the target faces. © 2011 American Academy of Forensic Sciences.


Kim C.H.,Chonnam National University | Kim B.-H.,Daegu University
Electrochimica Acta | Year: 2014

Organic-inorganic hybrid composite carbon nanofibers (CCNFs) are prepared by one-step electrospinning and subsequent thermal treatment using polyphenylsilane (PPS) as an inorganic precursor. We investigate the structural properties and electrochemical behavior of these CCNF materials when applied as supercapacitor electrodes as a function of the carbonization temperature ranging from 800 to 1000°C. The introduction of PPS induces thermal stability for the organic-inorganic hybrid CCNFs via the incorporation of a porous structure with stabilized functional structures such as silicon oxynitride (SiO xNy) and silicon oxycarbide (SiOxC y). This phenomenon is attributed to the synergistic effect of both the double-layer capacitance and the pseudo-capacitive effect induced by the porous carbon layer and the some surface functionalities), thereby providing high charge capacity, power and energy density. © 2013 Elsevier Ltd. All rights reserved.


Xu Z.,Tianjin Medical University | Xu Z.,University of North Carolina at Chapel Hill | Kim S.,Chonnam National University | Huh J.,Seoul National University
Journal of Molecular and Cellular Cardiology | Year: 2014

This study investigated if zinc plays a role in postconditioning-induced cardioprotection in rat hearts. Isolated rat hearts were subjected to 30min regional ischemia followed by 2h of reperfusion. Postconditioning was elicited by 6cycles of 10s reperfusion and 10s ischemia. Cytosolic zinc concentrations were measured with inductively coupled plasma optical emission spectroscopy (ICPOES). Infarct size was assessed by triphenyltetrazolium chloride staining. Cytosolic zinc concentrations were decreased dramatically upon reperfusion in the control hearts. In contrast, postconditioning increased cytosolic zinc levels at reperfusion. The anti-infarct effect of postconditioning was inhibited by the selective zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN). Postconditioning significantly increased phosphorylation levels of the reperfusion injury salvage kinases (RISK) including Akt (Ser473), extracellular signal-regulated kinase1/2 (ERK1/2) (Thr202/Tyr204), and glycogen synthase kinase-3β (GSK-3β) (Ser9) at reperfusion, which were nullified by TPEN. Postconditioning decreased the activity of protein phosphatase 2A (PP2A) in a zinc-dependent manner. Knockdown of the zinc transporter Zip2 inhibited the protective effect of postconditioning on hypoxia/reoxygenation injury in H9c2 cells. These results suggest that zinc plays an important role in the cardioprotective effect of postconditioning presumably by enhancing the activation of the RISK pathway. Zip2 and inactivation of PP2A by zinc may, at least in part, account for the activation of the RISK pathway. © 2013 Elsevier Ltd.


Kim B.-H.,Daegu University | Yang K.S.,Chonnam National University | Yang D.J.,University of Texas at Dallas
Electrochimica Acta | Year: 2013

Mesopore-enriched activated carbon nanofiber (ACNF) mats are produced by incorporating vanadium(V)oxide (V2O5) into polyacrylonitrile (PAN) via electrospinning, and their electrochemical properties areinvestigated as an electrode in supercapacitors. The microstructures of the ACNFs (e.g., nanometer-sizediameter, high specific surface area, narrow pore size distribution, and tunable porosity) are changed,and the textural parameters are found to affect the electrochemical properties significantly through thedifferent V2O5 loadings and activation process. The V2O5/PAN-based ACNF electrodes with well-balancedmicro/mesoporosity having an optimal pore range for effective double layer formation in an organicmedium are expected to be useful electrode materials for supercapacitor applications. © 2013 Elsevier Ltd. All rights reserved.


Kim M.G.,Seoul National University | Han N.,Seoul National University | Lee E.-K.,Sungkyunkwan University | Kim T.,Chonnam National University
Bone Marrow Transplantation | Year: 2015

Trial outcomes comparing cytokine agents for PBSC mobilization in autologous hematopoietic transplant patients have been controversial. We performed a systematic review and meta-analysis of evidence available on pegfilgrastim vs filgrastim in chemo-cytokine mobilization. Electronic literature searches of PubMed, EMBASE and CENTRAL identified nine articles eligible for qualitative analysis with one randomized controlled trial. Eight articles involving 719 patients were included in the meta-analysis. Results showed similar CD34+ cell collection yields for pegfilgrastim and filgrastim (SDM -0.08, 95% CI: -0.388 to 0.228). On comparison with filgrastim, pegfilgrastim showed a significantly earlier apheresis onset time (SDM: -0.512, 95% CI: -0.973 to -0.050) and reduction in required apheresis procedures (SDM -0.260, 95% CI: -0.466 to -0.054). Times to leukocyte (≥1.0 × 10 9 /L) and platelet (≥20 × 10 9 /L) recovery were similar between groups (SDM: 0.015, 95% CI: -0.41 to 0.44 and SDM: 0.309, 95% CI: -0.11 to 0.72, respectively). Both agents were well tolerated and mild bone pain was the most frequently reported adverse event. Pegfilgrastim may be a convenient alternative to filgrastim in PBSC mobilization for multiple myeloma and lymphoma patients, but further studies are required to clarify effects of cytokine dosage and previous cytotoxic exposure in specific subpopulations. © 2015 Macmillan Publishers Limited.


Kim S.S.,Chonnam National University | Park Y.-K.,Kyung Hee University
Cancer and Metastasis Reviews | Year: 2014

Osteosarcoma is the most common malignant bone tumor in children and characterized by aggressive biologic behavior of metastatic propensity to the lung. Change of treatment paradigm brings survival benefit; however, 5-year survival rate is still low in patients having metastastatic foci at diagnosis for a few decades. Metastasis-associated protein (MTA) family is a group of ubiquitously expressed coregulators, which influences on tumor invasiveness or metastasis. MTA1 has been investigated in various cancers including osteosarcoma, and its overexpression is associated with high-risk features of cancers. In this review, we described various molecular studies of osteosarcoma, especially associated with MTA1. © 2014, Springer Science+Business Media New York.


Kim T.H.,Chonnam National University
International journal of nanomedicine | Year: 2011

Celecoxib, a cyclo-oxygenase (COX)-2 inhibitor, has been reported to mediate growth inhibitory effects and to induce apoptosis in various cancer cell lines. In this study, we examined the potential effects of celecoxib on glioma cell proliferation, migration, and inhibition of COX-2 expression in vitro. Celecoxib was incorporated into poly DL-lactide-co-glycolide (PLGA) nanoparticles for antitumor drug delivery. PLGA nanoparticles incorporating celecoxib had spherical shapes and their particle sizes were in the range of 50-200 nm. Drug-loading efficiency was not significantly changed according to the solvent used, except for acetone. Celecoxib was released from the PLGA nanoparticles for more than 2 days, and the higher the drug content, the longer the duration of drug release. PLGA nanoparticles incorporating celecoxib showed cytotoxicity against U87MG tumor cells similar to that of celecoxib administered alone. Furthermore, celecoxib did not affect the degree of migration of U87MG cells. PLGA nanoparticles incorporating celecoxib showed dose-dependent cytotoxicity similar to that of celecoxib alone in C6 rat glioma cells. Western blot assay of the C6 cells showed that neither celecoxib alone nor PLGA nanoparticles incorporating celecoxib affected COX-2 expression. PLGA nanoparticles incorporating celecoxib had antitumor activity similar to that of celecoxib alone, even though these particles did not affect the degree of migration or COX-2 expression in the tumor cells.


Byun H.-S.,Chonnam National University
Journal of Industrial and Engineering Chemistry | Year: 2013

In this work, cloud-point and bubble-point phase behavior data are reported for the poly(dimethylsiloxane) [PDMSA] in supercritical carbon dioxide, propane, propylene, butane, 1-butene and dimethyl ether (DME). The static-type method, using a variable-volume view cell, was employed to obtain the experimental data at the temperature range for (315.2-454.9)K and pressure up to 55.52MPa. PDMS (Mw=38,900)+C4 cloud-point curves are ∼10MPa lower than the PDMS+C3 curves at constant temperature of 423K. Cloud-point curves for the PDMS+solvents system show the lower critical solution temperature (LCST) region. © 2012 The Korean Society of Industrial and Engineering Chemistry.


Hessari P.,Kyungpook National University | Shin B.-C.,Chonnam National University
Computers and Mathematics with Applications | Year: 2013

A spectral collocation approximation of first-order system least squares for incompressible Stokes equations was analyzed in Kim et al. (2004) [12], and finite element approximations for incompressible Navier-Stokes equations were developed in Bochev et al. (1998,1999) [9,10]. The aim of this paper is to analyze the first-order system least-squares pseudo-spectral method for incompressible Navier-Stokes equations. The paper will be an extension of the result in Kim et al. (2004) [12] to the Navier-Stokes equations. Our least-squares functional is defined by the sum of discrete spectral norms of a first-order system of equations corresponding to the Navier-Stokes equations based on Legendre-Gauss-Lobatto points. We show its ellipticity and continuity over an appropriate product space, and spectral convergences of discretization errors are derived in the H1-norm and the L2-norm in each variable. Finally, we present some numerical examples. © 2013 Elsevier Ltd. All rights reserved.


Lee J.,Chonnam National University | Kim Y.,Chungbuk National University
Journal of Industrial and Engineering Chemistry | Year: 2012

Four zirconium complexes containing fully deprotonated 2-(2H-benzo[d][1,2,3]triazol-2-yl)-4,6-di- tert-pentylphenol were used as catalysts for the polymerization of ethylene. In the presence of methylalumoxane (MAO) as a cocatalyst, the precursors were highly active for polyethylene with bimodal or multimodal molecular weight distribution. © 2011 The Korean Society of Industrial and Engineering Chemistry.


Cheung K.,National Tsing Hua University | Cheung K.,Konkuk University | Lee J.S.,Chonnam National University | Tseng P.-Y.,National Tsing Hua University
Journal of High Energy Physics | Year: 2014

We perform global fits to general two-Higgs doublet models (2HDMs) with generalized couplings using the most updated data from ATLAS, CMS, and Tevatron. We include both scenarios with CP-conserving and CP-violating couplings. By relaxing the requirement on the discrete symmetries that are often imposed on the Yukawa couplings, we try to see which of the 2HDMs is preferred. We found that (i) Higgcision in 2HDMs can be performed efficiently by using only 4 parameters including the charged Higgs contributions to the Higgs couplings to two photons, (ii) the differences among various types of 2HDMs are very small with respect to the chi-square fits, (iii) tan β is constrained to be small, (iv) the p-values for various fits in 2HDMs are worse than that of the standard model. Finally, we put emphasis on our findings that future precision measurements of the Higgs coupling to the scalar top-quark bilinear {C u S) and tan β may endow us with the discriminating power among various types of 2HDMs especially when Cu S deviates from its SM value 1. © 2014 The Author(s).


Kim T.-J.,Hanyang University | Kim T.-J.,Chonnam National University | Kim T.-H.,Hanyang University
Joint Bone Spine | Year: 2010

Objectives: The aim of this study was to determine the clinical profile of ankylosing spondylitis (AS) in Korea. Methods: A total of 732 men and 98 women with AS were recruited for the cross-sectional component of the Hanyang University ankylosing spondylitis (HYAS) Study. All participants completed extensive questionnaires about their medical and personal histories, and two rheumatologists concomitantly performed clinical evaluation and previous medical record reviews for all participants. Results: The mean age of onset (SD) was 20.9 (8.1) years. Three hundred and ninety-one patients (47.1%) were found to have a history of peripheral arthritis. Six hundred and four patients (73.9%) were found to have a history of hip joint involvement. Two hundred and thirty-six patients (28.7%) were found to be juvenile-onset AS (JoAS) patients. The frequency of uveitis differed between the sexes (28.2% of men vs 40.8% of women; p = 0.03; OR: 1.63; 95% CI: 1.05-2.53). Peripheral arthritis (p < 0.001; OR: 4.19; 95% CI: 2.98-5.88) and hip joint involvement (p < 0.001; OR: 2.76; 95% CI; 1.77-4.29) were more frequent in JoAS group. HLA-B27 positive cases had a significantly younger age of symptom onset (by 5.3 years), more uveitis, and a higher frequency of hip joint involvement than HLA-B27 negative patients. Conclusions: The clinical features of our patients are largely similar to those in other studies, with a few noticeable differences: 1) AS patients in Korea have a higher prevalence of peripheral arthritis and hip joint involvement; 2) female patients have more uveitis, and; 3) JoAS is common in our group. © 2010 Société française de rhumatologie.


Bae J.,Korea Institute for Advanced Study | Hwang W.-Y.,Chonnam National University | Han Y.-D.,Woosuk University
Physical Review Letters | Year: 2011

We provide a general framework of utilizing the no-signaling principle in derivation of the guessing probability in the minimum-error quantum state discrimination. We show that, remarkably, the guessing probability can be determined by the no-signaling principle. This is shown by proving that, in the semidefinite programing for the discrimination, the optimality condition corresponds to the constraint that quantum theory cannot be used for a superluminal communication. Finally, a general bound to the guessing probability is presented in a closed form. © 2011 American Physical Society.


Park S.C.,Chonnam National University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

Recently the CMS Collaboration at the LHC reported "the first direct limit on black hole production at a particle accelerator" using a data sample corresponding to an integrated luminosity of 35 pb-1 of pp collision at a center of mass energy of 7 TeV (Khachatryan et al., 2011) [1]. Even though the result has a strong impact on future searches, the interpretation lacks enough theoretical support. In this Letter, we show that the parameter range which was considered by the CMS Collaboration is actually out of the validity range of semi-classical black hole picture so that the Monte Carlo simulation result which was crucially used in the analysis still needs further solid scientific basis. © 2011 Elsevier B.V.


Moon H.S.,Pusan National University | No H.-R.,Chonnam National University
Journal of the Optical Society of America B: Optical Physics | Year: 2014

We report the physical origins of the on-resonant and off-resonant two-photon absorption (TPA) in an open-laddertype atomic system of the 5S 1?2 (F = 1)-5P3?2(F0 = 0; 1; 2)-5D5?2(F00 =1; 2; 3) transitions in 87Rb atoms. When the onresonant TPA, including electromagnetically induced transparency (EIT), was transformed into the off-resonant TPA according to the coupling laser frequency detuning, we clarified the dynamics of the atomic coherences by decomposing into the two-photon coherence (TC) and the crossover coherence (CC) terms mixed between onephoton coherence (OC) and TC terms. The physical origins of the two TPAs were completely different; the cause of the on-resonant TPA was the CC term, and that of the off-resonant TPA was the TC term. © 2014 Optical Society of America.


Lyu S.O.,Dongseo University | Oh C.-O.,Chonnam National University
Leisure Sciences | Year: 2014

Unlike prospective participants with desire for initial participation, current participants are likely to have different interest in habitual leisure engagement from participation itself. Accordingly, they may respond to the effects of leisure constraints differently in order to progress toward a higher level of leisure involvement. This study aims to construct a theoretical framework that demonstrates how diverse components of current participants’ constraints negotiation process are conceptually connected to each other. Study results suggest that different negotiation strategies help current participants adjust their willingness to participate in the activity more frequently. Results also denote that the three dimensions of leisure constraints are differently associated with cognitive negotiation strategies, and commitment plays an important role in promoting the use of negotiation strategies to mitigate current participants’ perception of leisure constraints. © 2014, © Taylor & Francis Group, LLC.


Chung C.Y.,Chonnam National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2012

Kaposi sarcoma (KS) is a vascular neoplasm, which is fairly prevalent in acquired immunodeficiency syndrome (AIDS) patients. Mucocutaneous and lymph node involvements are characteristic features of KS in AIDS patients. The involvement of gastrointestinal tract occurs in 40% of KS patients and leads to significant morbidity and mortality. In the highly active antiretroviral therapy (HAART) era, the rate of AIDS related KS has fallen with control of human immunodeficiency virus (HIV) viremia. However, it is still recognized as the primary AIDS-defining illness, and the proportion of AIDS diagnoses made due to KS ranged from 4.1% to 7.5%. In Korea, AIDS-related KS has been report in low rate incidence. Its gastrointestinal involvements are rarely reported. To date, five cases have been recorded in Korea. Herein, we present an additional case of gastrointestinal KS as the AIDS-defining illness and review of the Korean medical literature.


Moon H.S.,Pusan National University | Noh H.R.,Chonnam National University
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2011

We have investigated the optical pumping effects of single-resonance optical pumping (SROP) and double-resonance optical pumping (DROP) in the ladder-type electromagnetically induced transparency (EIT) of the 5S 1/2-5P3/2-5D3/2 transition of 87Rb atoms. In the 5S1/2(F = 2)-5P3/2(F′ = 3)-5D 3/2(F″ = 2, 3) transition with the single-resonance cycling 5S1/2(F = 2)-5P3/2(F′ = 3) transition, we observed the transmittance spectrum due to DROP and EIT. Based on our experimental results investigated according to the laser power (the probe and the coupling) and the coupling laser detuning, we revealed that DROP was significant for the transmittance spectrum. Particularly, in the 5S1/2(F = 2)-5P 3/2(F′ = 1, 2)-5D3/2(F″ = 1) transition without a cycling transition, we observed the two-photon absorption due to two-photon atomic coherence, when the probe laser power was weak and the coupling laser power was strong. © 2011 IOP Publishing Ltd.


Lee S.-Y.,Chonnam National University | Klassen R.D.,University of Western Ontario | Furlan A.,University of Padua | Vinelli A.,University of Padua
International Journal of Production Economics | Year: 2014

The bullwhip effect has long been recognized as a critical factor that amplifies demand variability as customer orders pass upstream through successive tiers of a supply chain. Like customer demand, environmental requirements also change significantly at times, and are passed along the supply chain to varying degrees, suggestive of what we term, the "green bullwhip effect". Based on field cases exploring changes in three supply chains across three adjacent tiers, we find evidence that such a phenomenon exists. First, ratcheting demands for better environmental performance are passed upstream through successive tiers with significant variation. Second, a green bullwhip effect is created as time to comply with specifications is compressed. Four different managerial responses, namely replace, accommodate, negotiate and collaborate, were observed to amplify or attenuate a green bullwhip effect based on the nature of firm relationships and balance of environmental capabilities at each tier. Of particular interest, the green bullwhip effect can force positive change, triggering the development of new environmental capabilities at multiple tiers in a supply chain. © 2014 The Authors.


This study examines the existing and anticipated technology strategies for reducing greenhouse gas (GHG) emissions in Korea's petrochemical and steel industries. The results of the cluster analysis identify three types of technology strategies employed by firms for reducing GHG emissions: "wait-and-see" "in-process-focused", and "all-round" strategies. The "in-process-focused" strategy was the most widely used strategy, followed by the "all-round" strategy. However, firms in these industries are expected to change their technology strategies to "treatment-reliance", "inbound- substitution", and "all-round" strategies in 5-10 years by employing a wider range of technology options to respond more effectively to the issue of GHG emissions. The demand for new energy sources and raw material substitutes is expected to strengthen in the near future as related technologies advance rapidly and become more widely available. © 2010 Elsevier Ltd. All rights reserved.


Kim S.,Chonnam National University
Fibers and Polymers | Year: 2011

A fabric drape shape database has been prepared to find the optimum combination of fabric physical properties for simulating the appearance of an actual fabric. First, an objective and quantitative evaluation method for the traditional Cusick drape tester has been devised. Then a virtual drape tester has been developed using an implicit integration based drape simulation engine to generate a series of virtually draped fabric with various physical properties. Finally, a search algorithm has been developed to find the optimum property combination for target fabric by comparing the simulated results with the Cusick drape tester result of that fabric. © 2011 The Korean Fiber Society and Springer Netherlands.


Kim Y.,Chonnam National University | Hong O.,University of California at San Francisco
American Journal of Health Behavior | Year: 2013

Objectives: To understand the predictors of controlled drinking in Korean male workers with a structural equation modeling based on Ajzen's theory of planned behavior. Methods: A cross-sectional survey design was used with a total of 315 male workers from 20 workplaces. Results: The modified model accounted for 58% of intentions and 20% of controlled drinking behavior. The component most increasing intentions was perceived behavior control (PBC), and the components increasing controlled drinking behavior were intentions and PBC in the modified model. Conclusions: Intervention programs should be designed to increase intentions and PBC to improve controlled drinking behavior in male workers.


Oh J.,Chonnam National University | Lee C.,Seoul National University of Science and Technology
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2015

As the need for efficient methods to accurately update and refine geospatial satellite image databases is increasing, we have proposed the use of 3-dimensional digital maps for the fully-automated RPCs bias compensation of high resolution satellite imagery. The basic idea is that the map features are scaled and aligned to the image features, except for the local shift, through the RPCs-based image projection, and then the shifts are automatically determined over the entire image space by template-based edge matching of the heterogeneous data set. This enables modeling of RPCs bias compensation parameters for accurate georeferencing. The map features are selected based on four suggested rules. Experiments were carried out for three Kompsat-2 images and stereo IKONOS images with 1:5000 scale Korean national topographic maps. Image matching performance is discussed with justification of the parameter selection, and the georeferencing accuracy is analyzed. The experimental results showed the automated approach can achieve one-pixel level of georeferencing accuracy, enabling economical hybrid map creation as well as large scale map updates. © 2014 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).


The optimal dose of remifentanil to attenuate the cardiovascular responses to tracheal intubation in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia has not been established. We compared the effects of two low doses of remifentanil on the cardiovascular responses to tracheal intubation and neonatal outcomes. Forty-eight women with severe pre-eclampsia were randomly assigned to receive either remifentanil 0.5 μg kg1 (R0.5 group, n=24) or 1 μg kg1 (R1.0 group, n=24) over 30 s before induction of anaesthesia using thiopental 5 mg kg1 and succinylcholine 1.5 mg kg1. Systolic arterial pressure (SAP), heart rate (HR), and plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis. SAP was decreased by induction of anaesthesia and increased by tracheal intubation in both groups. The peak SAP after intubation was greater in the R0.5 group than in the R1.0 group, whereas it did not exceed baseline values in either group. HR increased significantly above baseline in both groups with no significant differences between the groups. Three subjects in the R1.0 group received ephedrine due to hypotension (SAP < 90 mm Hg). Norepinephrine concentrations remained unaltered after intubation and increased significantly at delivery with no significant differences between the groups. Neonatal Apgar scores and umbilical arterial and venous pH and blood gas values were comparable between the groups. Both doses of remifentanil effectively attenuated haemodynamic responses to tracheal intubation with transient neonatal respiratory depression in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. The 1.0 μg kg1 dose was associated with hypotension in three of 24 subjects.


Yang S.J.,Chonnam National University | Lim Y.,Kyung Hee University
Metabolism: Clinical and Experimental | Year: 2014

Objective Resveratrol (RSV) regulates NAD bioavailability and sirtuin-related metabolism, which relates to aging, metabolic syndrome and non-alcoholic fatty liver disease. The purpose of this study was to investigate the effects of resveratrol on hepatic metaflammation in a rodent model of high-fat (HF) diet-induced obesity (DIO). Materials/Methods DIO was induced in a subset of mice given an HF diet (45% kcal fat). After 6 weeks of HF diet feeding, RSV was delivered via an osmotic pump for 4 weeks. The experimental groups were as follows: 1) lean control fed with a standard diet, 2) HF diet-induced obese control, and 3) HF-RSV (8 mg/kg/day). After 4 weeks of each treatment, blood and liver tissues were collected and the indices of glucose control, serum and liver triglyceride (TG), sirtuin pathway, inflammation, and NOD-like receptor family, pryin domain containing 3 (NLRP3) inflammasome were analyzed. Results Body weight and food intake were not altered by administering resveratrol. Glucose control was impaired, and serum and liver TG levels were increased by the HF diet. Hepatic inflammation was aggravated in mice fed with the HF diet, as shown by the increased levels of the pro-inflammatory markers interleukin-1 (IL-1), IL-6 and tumor necrosis factor-alpha in the liver. However, resveratrol administration significantly improved glucose control, and serum and liver TG contents. Also, resveratrol treatment reduced the levels of the pro-inflammatory markers. These improvements were accompanied by alterations in sirtuin pathway and NLRP3 inflammasome activation. Conclusion These results demonstrate that resveratrol ameliorates hepatic metaflammation, accompanied by alterations in NLRP3 inflammasome. © 2014 Elsevier Inc. All rights reserved.


Jung S.,Chonnam National University
Bioresource technology | Year: 2010

Transgenic tobacco plants expressing the hyperthermostable beta-glucosidase BglB of Thermotoga maritima were generated with the goal of cost-effective production of the enzyme for the application in bioconversion of lignocellulosic biomass. The enzyme was targeted to the cytosol and chloroplasts, where it accumulated to level of 4.5% and 5.8% of total soluble protein, respectively. The optimal temperature and pH of the plant-expressed BglB was 80 degrees C and 4.5, respectively. BglB activity was preserved in leaves after lyophilization, but decreased by over 70% with drying at room temperature. When BglB was synergistically supplied in a 1% (w/v) rice straw with Cel5A for efficient cellulase conversion, a 37% increase in glucose was observed. This report demonstrates the potential of utilizing transgenic tobacco for mass production of BglB. Copyright 2010 Elsevier Ltd. All rights reserved.


Unnithan A.R.,Chonbuk National University | Gnanasekaran G.,Chonnam National University | Sathishkumar Y.,Chonbuk National University | Lee Y.S.,Chonbuk National University | Kim C.S.,Chonbuk National University
Carbohydrate Polymers | Year: 2014

In this study, an antibacterial electrospun nanofibrous scaffolds with diameters around 400-700 nm were prepared by physically blending polyurethane (PU) with two biopolymers such as cellulose acetate (CA) and zein. Here, PU was used as the foundation polymer, was blended with CA and zein to achieve desirable properties such as better hydrophilicity, excellent cell attachment, proliferation and blood clotting ability. To prevent common clinical infections, an antimicrobial agent, streptomycin sulfate was incorporated into the electrospun fibers and its antimicrobial ability against the gram negative and gram positive bacteria were examined. The interaction between fibroblasts and the PU-CA and PU-CA-zein-drug scaffolds such as viability, proliferation, and attachment were characterized. PU-CA-zein-drug composite nanoscaffold showed enhanced blood clotting ability in comparison with pristine PU nanofibers. The presence of CA and zein in the nanofiber membrane improved its hydrophilicity, bioactivity and created a moist environment for the wound, which can accelerate wound recovery. © 2013 Elsevier Ltd.


Jung H.-Y.,Kangwon National University | Jung H.-Y.,Chonnam National University | Kim J.W.,Kangwon National University
International Journal of Hydrogen Energy | Year: 2012

The glass transition temperature (T g) of the Nafion 117 membrane was traced by DSC step by step during the preparation of the membrane electrode assembly (MEA). Wide-angle x-ray diffraction and frequency response analysis were used for the determination of the crystallinity and proton conductivity of the membrane. As-received Nafion 117 membrane showed two glass transition temperatures in the DSC thermogram. The first T g, caused by the mobility of the main chain in the polymer matrix, was 125°C; the second T g, derived from the side chain due to the strong interaction between the sulfonic acid functional groups, was 195°C. During the pretreatment of the membrane, the T g of the Nafion 117 membrane drastically decreased because of the plasticizer effect of water. In the hot-pressing process, the T g of the Nafion 117 membrane gradually increased due to the loss of water. When the Nafion 117 was completely dried, the T g of the membrane finally reached 132°C. Thermal heat treatment was then applied to the MEA to obtain high interfacial stability; however, the membrane developed a crystalline morphology that led to reduced water uptake and proton conductivity. Therefore, the thermal heat treatment of the MEA should be carefully controlled in the region of the glass transition temperature (120-140°C) of the Nafion 117 membrane to ensure the high performance of the MEA. © 2012 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


We present an analytical calculation of temporal evolution of populations for optically pumped atoms under the influence of weak, circularly polarized light. The differential equations for the populations of magnetic sublevels in the excited state, derived from rate equations, are expressed in the form of inhomogeneous second-order differential equations with constant coefficients. We present a general method of analytically solving these differential equations, and obtain explicit analytical forms of the populations of the ground state at the lowest order in the saturation parameter. The obtained populations can be used to calculate lineshapes in various laser spectroscopies, considering transit time relaxation. © 2016 MDPI.


Jeong J.-T.,Chonnam National University
Theoretical and Computational Fluid Dynamics | Year: 2012

The free-surface shape and cusp formation are analyzed by considering a viscous flow arising from the superposition of a source/sink and vortex below the free surface where the strength of the source and vortex are arbitrary. In the analysis, Stokes' approximation is used and surface tension effects are included, but gravity is neglected. The solution is obtained analytically by using conformal mapping and complex function theory. From the solution, shapes of the free surface are obtained, and the formation of a cusp on the free surface is discussed. Above some critical capillary number with a sink, the free-surface shape becomes singular and an apparent cusp should form on the free surface below a real fluid. On the other hand, no cusp would occur for sources of zero or positive strength. Typical streamline patterns are also shown for some capillary numbers. As the capillary number vanishes, the solution is reduced to a linearized potential flow solution. © Springer-Verlag 2011.


Yang H.C.,Chonnam National University
Journal of Visualization | Year: 2015

Abstract: The behavior of gas–liquid two-phase jets has been extensively studied over many years, due to their fundamental importance in many multiphase systems. Understanding jet behaviors is essential for predicting many processes of practical importance. The objective of this study is to investigate horizontal air–water jet behavior with an annular nozzle ejector in a shallow water tank and to present the effect of overall jet behavior on oxygen transfer characteristics from air bubbles to water. The experimental apparatus consisted of an electric motor-pump, an annular nozzle ejector assembly, a high-speed camera unit, a circulation water tank, and measuring or controlling accessories. The images of the air–water mixed jet issuing from the ejector are analyzed qualitatively, and the dissolved oxygen concentration is measured using the clean water unsteady state technique. The horizontal mixed jet behaves like a buoyancy jet, a quasi-horizontal bubble jet, or a horizontal momentum jet owing to the momentum of the primary flow and air bubble size. It can be concluded that the higher the momentum of primary water flow and the lower the entrainment ratio, the smaller the air bubble size. The buoyancy force of the air bubble and the penetration of the mixed flow are found to be important parameters for the oxygen transfer rate owing to the contact area and time of the two phases.Graphical Abstract: [Figure not available: see fulltext.] © 2014, The Visualization Society of Japan.


Kim Y.J.,Chonnam National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2012

We report herein a case of intestinal amyloidosis with grave prognosis that caused intractable diarrhea and intestinal pseudo-obstruction, alternately in spite of intensive conservative treatment. A 44-year-old woman was admitted for fever, diarrhea, and crampy abdominal pain which had been continuned during 6 months. Abdomen CT scan showed edematous wall thickening of the small bowel and right colon, and colonoscopic biopsy revealed amyloid deposition in the mucosa. Monoclonal light chains in serum and/or urine were not detected and highly elevated serum amyloid A was shown. In spite of intensive treatment including oral prednisolone and colchicine, diarrhea and intestinal pseudo-obstruction developed alternately, general status rapidly got worsened and died after two months.


Chang J.,National Tsing Hua University | Cheung K.,National Tsing Hua University | Cheung K.,Konkuk University | Lee J.S.,Chonnam National University | Lu C.-T.,National Tsing Hua University
Journal of High Energy Physics | Year: 2014

Associated production of the Higgs boson with a single top quark proceeds through Feynman diagrams, which are either proportional to the hW W, top-Yukawa, or the bottom-Yukawa couplings. It was shown in literature that the interference between the top-Yukawa and the gauge-Higgs diagrams can be significant, and thus the measurement of the cross sections can help pin down the sign and the size of the top-Yukawa coupling. Here we perform a detailed study with full detector simulations of such a possibility at the LHC-14 within the current allowed range of hW W and top-Yukawa couplings, using h → b overline b, γγ, τ + τ -, ZZ → 4ℓmodes. We found that the LHC-14 has the potential to distinguish the size and the sign of the top-Yukawa coupling. Among the channels the h → b overline b mode provides the best chance to probe the signal, followed by the h → γγ mode, which has the advantage of a narrow reconstructed mass peak. We also pointed out that the spatial separation among the final-state particles has the potential in differentiating among various values of the top-Yukawa coupling. © 2014 The Author(s).


Senthilkumar B.,Bharathiar University | Senthilkumar B.,Murdoch University | Meyrick D.,Murdoch University | Lee Y.-S.,Chonnam National University | Selvan R.K.,Bharathiar University
RSC Advances | Year: 2013

Nano-sized β-NiMoO4-CoMoO4·xH 2O composites were synthesized by a solution combustion synthesis (SCS) technique. The effect of weight ratio of transition metal on the electrochemical capacitive performance of the nanocomposites was investigated by cyclic voltammetry and galvanostatic charge-discharge methods. The NiMoO 4-CoMoO4·xH2O nanocomposite with weight ratio of 3:1 (Ni:Co) exhibits enhanced capacitive behaviour relative to other composites and delivered a maximum specific capacitance of 1472 Fg-1 at a current density of 5 mAcm-2. The enhancement in specific capacitance is due to the small particle size, uniform size distribution, high surface area and high weight fraction of Ni. The synergistic effect of nickel and cobalt improves the electrochemical behaviour relative to pure nickel and cobalt molybdates. A full cell was fabricated using the β-NiMoO 4-CoMoO4·xH2O nanocomposite (3:1) and activated carbon (AC) as a positive and negative electrode, respectively. The cell delivered high capacitance (80 Fg-1) and energy density (28 Wh kg-1) and good cycling stability up to 1000 cycles. © The Royal Society of Chemistry 2013.


Well-developed rhythmic climbing-ripple cross-lamination (RCRL) was described from estuarine tidal channels in Gomso Bay, west coast of Korea. Associated with upper intertidal point bars of closely spaced meandering channels, RCRL occurs between mean sea level and mean neap high-water level. RCRL is typically less than 40 cm thick, and constitutes the upper part of fining-upward channel-fill successions that are capped by intensely bioturbated mud. RCRL consists of muddraped climbing-ripple cross-laminae that are continuous along strike direction of the channel for 10-20 m. Climbing patterns are dominantly supercritical and less commonly subcritical. Flood-oriented RCRL is developed in the landward part of the meander bend, while ebb-oriented RCRL is developed in the seaward part. RCRL demonstrates rhythmic change in crosslamination thickness, which resembles various hierarchical tidal cycles, such as diurnal inequality, synodic neap-spring tidal cycle, and anomalistic tidal cycle. Truncated tidal rhythmicities registered in RCRL and fine-grained textures are consistent with an upper intertidal origin. Common links of RCRL with inclined heterolithic stratification (IHS) and tight meander bends as well as high sedimentation rate is suggestive that RCRL can serve as a diagnostic indicator of active channel migration in the fluvio-estuarine transition. This study highlights the significance of RCRL bearing well-preserved tidal rhythmicities in the reconstruction of paleodepositional environment, paleoelevation in terms of tidal frame, and paleogeography. Copyright © 2010, SEPM (Sodety for Sedimentary Geology).


Yang S.K.,Chonnam National University | Zimmerman S.C.,University of Illinois at Urbana - Champaign
Israel Journal of Chemistry | Year: 2013

Supramolecular polymer chemistry has emerged as a major research focus within polymer science, because of the potential to improve material properties, through the combination of noncovalent interactions and synthetic polymers. As a supramolecular handle, the most useful noncovalent interaction is hydrogen bonding, which has been used extensively, because of advantages such as synthetic accessibility, directionality, fidelity, and, most importantly, responsiveness to external stimuli. This review introduces recent advances in the development of hydrogen bonding modules that can be useful for creating a variety of supramolecular polymers. Furthermore, we present selected examples of hydrogen bonded supramolecular polymers from the literature, by dividing them into three categories: supramolecular polymers assembled from small molecules, and main-chain and side-chain supramolecular polymers. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chung J.Y.,Chonnam National University
International orthopaedics | Year: 2013

To investigate the usefulness of titanium lamina mesh for posterior column reconstruction after total en bloc spondylectomy in patients with spinal tumour and evaluate the radiographic outcomes of this method. Eight patients who underwent total en bloc spondylectomy with posterior column reconstruction using titanium lamina mesh and bone graft to treat a spinal tumour were included in this study. The mean age at the time of surgery was 50.6 years (range, 16.5-70.9 years) and the mean follow-up duration was 50.2 months (range, 28.1-68.7 months). The pathological lesions were located from the T2 to L1 vertebrae. There were four patients in each primary and metastatic tumour group. For the posterior column reconstruction, titanium lamina mesh was used and bone graft was applied over the lamina mesh. Radiographic evaluation was used to investigate the displacement of lamina mesh and union of the grafted bone above lamina mesh. At the postoperative six month follow-up, a bony bridge on the titanium mesh between upper and lower adjacent lamina was observed in all cases, except for one with infection. On the last follow-up, there was no collapse or displacement of titanium lamina mesh, and there was no instability or malalignment of the spinal column. Posterior column reconstruction using titanium lamina mesh during total en bloc spondylectomy for spinal tumour was a useful surgical option that provided new lamina reconstruction for stability of spinal column and protection of the neural elements.


Bielecki T.,University of Silesia | Dohan Ehrenfest D.M.,Chonnam National University
Current Pharmaceutical Biotechnology | Year: 2012

The recent developement of platelet concentrate for surgical use is an evolution of the fibrin glue technologies used since many years. The initial concept of these autologous preparations was to concentrate platelets and their growth factors in a plasma solution, and to activate it into a fibrin gel on a surgical site, in order to improve local healing. These platelet suspensions were often called Platelet-Rich Plasma (PRP) like the platelet concentrate used in transfusion medicine, but many different technologies have in fact been developed; some of them are even no more platelet suspensions, but solid fibrin-based biomaterials called Platelet-Rich Fibrin (PRF). These various technologies were tested in many different clinical fields, particularly oral and maxillofacial surgery, Ear-Nose-Throat surgery, plastic surgery, orthopaedic surgery, sports medicine, gynecologic and cardiovascular surgery and ophthalmology. This field of research unfortunately suffers from the lack of a proper accurate terminology and the associated misunderstandings, and the literature on the topic is quite contradictory. Indeed, the effects of these preparations cannot be limited to their growth factor content: these products associate many actors of healing in synergy, such as leukocytes, fibrin matrix, and circulating progenitor cells, and are in fact as complex as blood itself. If platelet concentrates were first used as surgical adjuvants for the stimulation of healing (as fibrin glues enriched with growth factors), many applications for in situ regenerative medicine and tissue engineering were developed and offer a great potential. However, the future of this field is first dependent on his coherence and scientific clarity. The objectives of this article is to introduce the main definitions, problematics and perspectives that are described in this special issue of Current Pharmaceutical Biotechnology about platelet concentrates. © 2012 Bentham Science Publishers.


Youn S.-H.,Chonnam National University
Journal of the Korean Physical Society | Year: 2013

From the explicit form of the probability amplitude for two cascade-placed beam splitters (with one squeezed state input and two coherent state inputs), we calculated the probability amplitude of the output beam as a function of the transmittance of the two beam splitters and the amplitude and the relative phase of the three input states. At a certain condition, the output beam had no vacuum and was in a highly nonclassical state that contained more than one photon. Armed with explicit probability amplitude for two beam splitters and two coherent states, the squeezed vacuum state might be a very useful tool for generating highly nonclassical light. © 2013 The Korean Physical Society.


Park G.,Saga University | Gunawardhana N.,Saga University | Nakamura H.,Saga University | Lee Y.-S.,Chonnam National University | Yoshio M.,Saga University
Journal of Power Sources | Year: 2012

The electrochemical properties of graphite with various degrees of graphitization, contents of rhombohedral phase, and surface areas were electrochemically investigated at 25 °C and -5 °C. The degree of graphitization and the amount of rhombohedral phase affected the samples' lithium intercalation/deintercalation and surface deposition. The reductions of electrolyte conductivity and lithium ion diffusion in the graphite interlayer at -5 °C lowered the graphite's capacity. Lithium deposition also occurred on the graphite's surface. Highly graphitized samples were affected greatly by temperature, showing large capacity loss at low temperature. Increased rhombohedral phase facilitated lithium deposition on the graphite's surface as lithium ions did not insert into the graphite interlayers and accumulated at its edged planes. Increasing the pathways for lithium ion intercalation could facilitate lithium intercalation and reduce lithium deposition. © 2011 Elsevier B.V. All rights reserved.


Lee D.-H.,Dana-Farber Cancer Institute | Lee D.-H.,Chonnam National University | Acharya S.S.,Dana-Farber Cancer Institute | Kwon M.,Dana-Farber Cancer Institute | And 10 more authors.
Molecular Cell | Year: 2014

Excluding 53BP1 from chromatin is required to attenuate the DNA damage response during mitosis, yet the functional relevance and regulation of this exclusion are unclear. Here we show that 53BP1 is phosphorylated during mitosis on two residues, T1609 and S1618, located in its well-conserved ubiquitination-dependent recruitment (UDR) motif. Phosphorylating these sites blocks the interaction of the UDR motif with mononuclesomes containing ubiquitinated histone H2A and impedes binding of 53BP1 to mitotic chromatin. Ectopic recruitment of 53BP1-T1609A/S1618A to mitotic DNA lesions was associated with significant mitotic defects that could bereversed by inhibiting nonhomologous end-joining. We also reveal that protein phosphatase complex PP4C/R3β dephosphorylates T1609 and S1618 toallow the recruitment of 53BP1 to chromatin in G1 phase. Our results identify key sites of 53BP1 phosphorylation during mitosis, identify the counteracting phosphatase complex that restores the potential for DDR during interphase, and establish the physiological importance of this regulation. © 2014 Elsevier Inc.


Bae J.,National University of Singapore | Bae J.,ICFO - Institute of Photonic Sciences | Hwang W.-Y.,Chonnam National University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We show a geometric formulation for minimum-error discrimination of qubit states that can be applied to arbitrary sets of qubit states given with arbitrary a priori probabilities. In particular, when qubit states are given with equal a priori probabilities, we provide a systematic way of finding optimal discrimination and the complete solution in a closed form. This generally gives a bound to cases when prior probabilities are unequal. Then it is shown that the guessing probability does not depend on detailed relations among the given states, such as the angles between them, but on a property that can be assigned by the set of given states itself. This also shows how a set of quantum states can be modified such that the guessing probability remains the same. Optimal measurements are also characterized accordingly, and a general method of finding them is provided. © 2013 American Physical Society.


Ham Y.-G.,Chonnam National University | Kug J.-S.,Pohang University of Science and Technology
Climate Dynamics | Year: 2015

In this study, role of North Tropical Atlantic (NTA) SST on the ENSO variability is examined with CMIP3 and CMIP5 simulations. It is found that most climate models involved in CMIP3 and CMIP5 successfully simulate the inverse relationship between NTA SST during the boreal spring and the ENSO during the subsequent boreal winter. The multi-model ensemble (MME) results show the observed westward propagating signals related to NTA SST from the Atlantic to the Pacific along the off-equatorial Pacific ITCZ. However, different from the observational argument, the main mechanism for the NTA to induce the ENSO is likely to be different in the MME. While the observational result exhibits the NTA-induced off-equatorial Rossby waves play a more dominant role in leading the Pacific signal, the equatorial wind over the western Pacific related to the NTA-induced Kelvin wave is likely to be more crucial to lead the Pacific variability. In addition, the amplitude of NTA SST-induced ENSO in the MME tends to be systematically weaker, and the preference for the central Pacific SST anomaly is also weak. These weak signals are distinctly improved in a model that simulates two types of El Nino events independently. That the strength of the NTA effect to the Pacific can be affected by the seasonal distribution of climatological precipitation is also discussed. Additionally, the strength of the NTA effect tends to be stronger when the model simulates phase locking of ENSO reasonably. © 2015 Springer-Verlag Berlin Heidelberg


Lee S.J.,Chonnam National University
Arthritis research & therapy | Year: 2011

The purpose of this study was to analyze the cellular expressions of pro-resorptive cytokines in gouty tophus tissues, to determine the capacity of monosodium urate monohydrate (MSU) crystals to induce these cytokines, and to understand the mechanisms of bone destruction in chronic gout. Fourteen fixed, paraffin-embedded, uninfected tophus samples were analyzed immunohistochemically. Peripheral blood mononuclear cells (PBMCs) were cultured in vitro with MSU crystals, and gene expression was assessed by reverse transcription-polymerase chain reaction. In vitro osteoclastogenesis was performed using PBMCs and synovial fluid mononuclear cells (SFMCs). CD4+ T cells, CD8+ T cells, CD20+ B cells and mast cells infiltrated tophus tissues. Tartrate-resistant acid phosphatase (TRAP)+ osteoclasts were present around tophi and in osteolytic lesions. Interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF)-alpha were produced from infiltrated mononuclear cells, whereas receptor activator of nuclear factor κB ligand (RANKL) was strongly expressed in T cells. However, osteoprotegerin (OPG) was not or was weakly expressed in tophus tissues. MSU crystals induced the expressions of IL-1, IL-6, TNF-alpha and RANKL in PBMCs, but inhibited OPG expression. In addition, the pro-resorptive cytokines were highly expressed in SFMCs of gouty arthritis patients. Furthermore, in vitro osteoclastogenesis was enhanced in SFMC cultures, but inhibited in T cell-depleted SFMC cultures. Our study demonstrates that RANKL-expressing T cells and TRAP+ osteoclasts are present within gouty tophus tissues, and that infiltrating cells express pro-resorptive cytokines. Furthermore, our data show that MSU crystals have the potential to induce pro-resorptive cytokines, and T cells are involved in osteoclastogenesis in chronic gout.


ABSTRACT: Accurate repositioning of the maxillary and mandibular segment is essential to improve esthetics and function in orthognathic surgery. With the improvement of three-dimensional imaging technology and computer-aided design and manufacturing techniques, various computer-aided design and manufacturing templates have been developed as alternatives to the traditional error-prone and time-consuming intermediate splint. However, the majority of previously developed templates still use an intermediate splint or the structures connected to occlusal surface and transferred the preoperative virtual plan to the real operation field indirectly.Here, the authors introduce a technical note regarding maxillary surgical templates adjusted only by the maxillary surface configuration. These templates consist of osteotomy and repositioning guide templates that provide information about the osteotomy line, bony interference, and planned position and eliminate the need for an intermediate splint. Using these templates, the maxillomandibular complex can be successfully repositioned without using an intermediate splint. Further studies are needed to determine the accuracy and stability of maxillary templates. © 2016 by Mutaz B. Habal, MD.


Cho H.-Y.,Korea University | Lee Y.-B.,Chonnam National University
Journal of Nanoscience and Nanotechnology | Year: 2014

The lymphatic system plays important roles for immune responses, spreading cancer cells or viruses and disseminating infections. Thus, targeting drugs, such as anticancer, immunotherapeutic and lymphoid contrast agents, to both tumors and the lymphatics, has several advantages such as reduced systemic side effects and increased efficacy. For these reasons, much interest has been focused on the nature of the lymphatics and various studies on the lymphatic delivery of drugs have been carried out. Because the lymphatics consist of a single layer endothelium and have higher permeability compared with that of blood capillaries, studies using nano-sized carriers have been performed. Polymeric nanoparticles, liposomes, and lipid-based vehicles have been adopted as lymphatic delivery carriers. This review will focus on the clinical use of such nano-sized carriers that have been developed for imaging and drug delivery to the lymphatic system. Lymphatic delivery of drugs, such as anticancer, immunotherapeutic and lymphoid contrast agents, using nano-sized carriers has much more improved ability compared with that of conventional dosage forms, but it has not shown the specific lymphatic targeting ability yet. Finally, the challenges for the future are suggested in terms of the mechanisms governing the lymphatic delivery of nano-sized carriers. Copyright © 2014 American Scientific Publishers All rights reserved.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2016

C22H16Cl2N2Pd2, monoclinic, P21/c (no. 14), a = 7.2249(6) Å, b = 17.0538(14) Å, c = 8.4291(7) Å, β = 112.211(2)°, V = 961.50(14) Å3, Z = 2, Rgt(F) = 0.0217, wRref(F2) = 0.0496, T = 200(2) K. © 2016 Kwang Ha.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2016

C14H8N4PtS2, monoclinic, P21/n (no. 14), a = 7.3318(7) Å, b = 15.1300(15) Å, c = 12.5924(13) Å, β = 90.379(2)°, V = 1396.8(2) Å3, Z = 4, Rgt(F) = 0.0349, wRref(F2) = 0.0668, T = 183(2) K. © 2016 Kwang Ha.


Seo D.W.,KISTI | Lee J.Y.,Chonnam National University
Expert Systems with Applications | Year: 2013

Several studies have been carried out on augmented reality (AR)-based environments that deal with user interfaces for manipulating and interacting with virtual objects aimed at improving immersive feeling and natural interaction. Most of these studies have utilized AR paddles or AR cubes for interactions. However, these interactions overly constrain the users in their ability to directly manipulate AR objects and are limited in providing natural feeling in the user interface. This paper presents a novel approach to natural and intuitive interactions through a direct hand touchable interface in various AR-based user experiences. It combines markerless augmented reality with a depth camera to effectively detect multiple hand touches in an AR space. Furthermore, to simplify hand touch recognition, the point cloud generated by Kinect is analyzed and filtered out. The proposed approach can easily trigger AR interactions, and allows users to experience more intuitive and natural sensations and provides much control efficiency in diverse AR environments. Furthermore, it can easily solve the occlusion problem of the hand and arm region inherent in conventional AR approaches through the analysis of the extracted point cloud. We present the effectiveness and advantages of the proposed approach by demonstrating several implementation results such as interactive AR car design and touchable AR pamphlet. We also present an analysis of a usability study to compare the proposed approach with other well-known AR interactions. © 2012 Elsevier Ltd. All rights reserved.


Lee D.-S.,Korea Institute of Science and Technology | Je J.-Y.,Chonnam National University
Journal of Agricultural and Food Chemistry | Year: 2013

In this study, antimicrobial activity of gallic acid-grafted-chitosans (gallic acid-g-chitosans) against five Gram-positive and five Gram-negative foodborne pathogens was evaluated. The minimum inhibitory concentrations (MICs) of gallic acid-g-chitosans ranged from 16 to 64 μg/mL against Gram-positive bacteria and ranged from 128 to 512 μg/mL against Gram-negative bacteria. These activities were higher than those of unmodified chitosan. The bactericidal activity of gallic acid-g-chitosan (I), which showed the highest antimicrobial activity, was evaluated by time-killing assay with multiples of MIC, and it was recognized to depend on its dose. The integrity of cell membrane, outer membrane (OM), inner membrane (IM) permeabilization experiments, and transmission electron microscopy (TEM) observation were conducted for elucidation of the detailed antimicrobial mode of action of gallic acid-g-chitosan. Results showed that treatment of gallic acid-g-chitosan (I) quickly increased the release of intracellular components for both Escherichia coli and Staphylococcus aureus. In addition, gallic acid-g-chitosan (I) also rapidly increased the 1-N-phenylanphthylamine (NPN) uptake and the release of β-galactosidase via increasing the permeability of OM and IM in E. coli. TEM observation demonstrated that gallic acid-g-chitosan (I) killed the bacteria via disrupting the cell membrane. © 2013 American Chemical Society.


Kim Y.-W.,Chonnam National University
Composites Part B: Engineering | Year: 2014

The free vibration characteristics of FGM cylindrical shells partially resting on elastic foundation with an oblique edge are investigated by an analytical method. The cylindrical shell is partially surrounded by an elastic foundation which is represented by the Pasternak model. An edge of an elastic foundation lies in a plane that is oblique at an angle with the shell axis. The motion of shell is represented based on the first order shear deformation theory (FSDT) to account for rotary inertia and transverse shear strains. The functionally graded cylindrical shell is composed of stainless steel and silicon nitride. Material properties vary continuously through the thickness according to a four-parameter power law distribution in terms of volume fraction of the constituents. The equation of motion for eigenvalue problem is obtained using Rayleigh-Ritz method and variational approach. To validate the present method, the numerical example is presented and compared with the available existing results. © 2014 Elsevier Ltd. All rights reserved.


Kang K.-J.,Chonnam National University
Progress in Materials Science | Year: 2015

Wire-woven metals are a type of cellular metal composed of uniform 3D truss-like cells, and fabricated using wires as the raw material. Wire-woven metals are practically the most common choice for lattice truss metals to achieve multi-layered structures with fine cells. Since the new millennium, a number of wire-woven metals have been developed. This paper reviews various wire-woven metals and introduces their topologies and fabrication processes. In addition, their mechanical and thermal properties with analytic solutions, their variations, and applications are presented. Finally, the limits and prospects of wire-woven metals are discussed. The future of wire-woven metals seems promising due to the many options in the selection of the mother material, cell size, overall size, relative density, and cell geometry. Furthermore, their mechanical and thermo-hydraulic properties are superior to their competitors such as metal foams and they can be mass-produced at low cost. © 2014 Elsevier Ltd. All rights reserved.


Kim S.,Chonnam National University
International Journal of Clothing Science and Technology | Year: 2015

Purpose-The purpose of this paper is to analyze automation of body surface shape.Design/methodology/approach-Numerous body landmarks are detected automatically. Body surface can be subdivided into multiple patches in a consistent manner using parametric design method. Findings-Complex surface shape of various human bodies can be analyzed easily and consistently. Research limitations/implications-The proposed method may not be applicable for a body with the shape which significantly differs from that of an average body. Practical implications-This method can greatly reduce the time required to analyze the surface shape of a three dimensional body scan data. Originality/value-The analysis of body surface shape is one of the most important processes especially in designing close fitting garments. The parametric design of body surface patches will facilitate the analysis of numerous body scan data. © Emerald Group Publishing Limited.


Cross-bracing (X-bracing) is one of the most popular methods of seismic retrofitting, and has been shown to significantly increase the structural stiffness and strength of buildings. Conventional steel X-bracing methods typically exhibit brittle failure at the connection between the brace and the building, or buckling failure of the braces. This study investigated the structural properties of a new type of non-compression X-bracing system using carbon fiber composite cable (CFCC). This non-compression X-bracing system uses CFCC bracing and bolt connections between structural members and the terminal fixer of the CFCC, instead of conventional steel bracing. The aim is to overcome the brittle and buckling failures that can occur at the connection and bracings with conventional steel X-bracing methods. We carried out cyclic loading tests, and the maximum load carrying capacity and deformation were investigated, as well as hysteresis in the lateral load-drift relations. The test results revealed that the CFCC X-bracing system installed in reinforced concrete frames enhanced the strength markedly, and buckling failure of the bracing was not observed. © 2015 by the author; licensee MDPI, Basel, Switzerland.


Yoon K.C.,Chonnam National University
Korean journal of ophthalmology : KJO | Year: 2011

The aim of this study is to report on preliminary data regarding the prevalence of major eye diseases in Korea. We obtained data from the Korea National Health and Nutrition Examination Survey, a nation-wide cross-sectional survey and examinations of the non-institutionalized civilian population in South Korea (n = 14,606), conducted from July 2008 to December 2009. Field survey teams included an ophthalmologist, nurses, and interviewers, traveled with a mobile examination unit and performed interviews and ophthalmologic examinations. The prevalence of visual impairment, myopia, hyperopia and astigmatism in participants over 5 years of age was 0.4 ± 0.1%, 53.7 ± 0.6%, 10.7 ± 0.4%, and 58.0 ± 0.6%, respectively. The prevalence of strabismus and blepharoptosis in participants over 3 years of age was 1.5 ± 0.1% and 11.0 ± 0.8%, respectively. In participants over 40 years of age, the prevalence of cataract, pterygium, early and late age-related macular degeneration, diabetic retinopathy and glaucoma was 40.2 ± 1.3%, 8.9 ± 0.5%, 5.1 ± 0.3%, 0.5 ± 0.1%, 13.4 ± 1.5%, and 2.1 ± 0.2%, respectively. This is the first nation-wide epidemiologic study conducted in South Korea for assessment of the prevalence of eye diseases by both the Korean Ophthalmologic Society and the Korea Center for Disease Control and Prevention. This study will provide preliminary information for use in further investigation, prevention, and management of eye diseases in Korea.


Jung S.,Chonnam National University
International Journal of Hydrogen Energy | Year: 2016

Methanol/water crossover through proton-exchange membranes and low cell voltage resulting from sluggish catalytic reactions are major issues that must be overcome to commercialize direct methanol fuel cells (DMFCs). Three key performance indices (low methanol crossover rate (MCO), low water-transfer coefficient, and high cell voltage) can be improved by optimizing the design of the DMFC membrane electrode assembly for the cell operating conditions. Using computational techniques with a one-dimensional DMFC model, the present study proposes guidelines for constructing a high-performance DMFC with a focus on membrane electrode assembly (MEA). First, the membrane thickness is determined by balancing the MCO and ionic conductivity for both the fluorocarbon (FC) membrane and the hydrocarbon (HC) membrane. Second, the material composition of the cathode catalyst layer (cCL) is optimized by balancing charge transfer and mass transfer. Finally, the anode diffusion layer (aDL) is optimized according to the cell operating conditions. Compared to the referenced baseline cell, this optimization process is predicted to improve the cell voltage by 19% and decrease methanol crossover by 64%. © 2016 Hydrogen Energy Publications, LLC.


Lee H.W.,Chonnam National University
Journal of the Korean Wood Science and Technology | Year: 2014

RPS (Renewable Portfolio Standard) has increased wood pellet demand dramatically in recent years in Korea where self-supply rate of wood pellet is not more than 10%. However global production capacity of wood pellet is prospected to be unable to meet the global demand after 2020. Therefore it is urgently needed to develop new sustainable biomass energy resources which can replace wood pellet at lower cost. As a result of this study EFB (empty fruit bunch) and MF (mesocarp fiber), the representative solid palm biomass, are estimated to be generated at the rate of 20 and 28 million tons per year (based on 10% moisture content) in Malaysia and Indonesia, respectively in 2012. Total annual generation rate of EFB and MF is estimated as 48 million tons per year only in Malaysia and Indonesia in 2012. With calorific value of over 90% of wood pellet EFB is expected to be a excellent biomass energy resource which can replace wood pellet. EFB can be utilized as fuel for power generation or industrial purpose. However EFB may not be a proper fuel for domestic and greenhouse heating because of its high ash content.


Park Y.,Chonnam National University | Kang D.-H.,Korean Intellectual Property Office
Journal of Vibroengineering | Year: 2013

In this paper, we present a technique for fatigue reliability evaluation of a steel welding member. The probabilistic stress-life method is an important one for the fatigue reliability evaluation of a steel welding member. In this method, the stress range frequency distribution of the stress history of a steel welding member defined as a loading block is obtained from the stress frequency analysis and the parameters of the probability distribution for the stress range frequency distribution are used for numerical simulation. The probability of failure of the steel welding member under loading block is obtained from the Monte Carlo Simulation in conjunction with the Miner's Rule, the Modified Miner's Rule, and the Haibach's Rule for fatigue damage evaluation. Through this procedure, a fatigue reliability evaluation that can predict the number of loading block of failure and the residual fatigue life is possible.


Kim G.-E.,Chonnam National University
Applied Immunohistochemistry and Molecular Morphology | Year: 2016

Raf kinase inhibitor protein’s (RKIP) downregulation can predict poor outcome in patients with various types of malignancy. In this study, we aimed to assess the potential involvement of RKIP in breast carcinogenesis and to evaluate its association with outcome variables and aberrant promoter methylation in breast carcinoma (BC). Tissue microarray sections were immunostained for RKIP in 26 normal breasts, 25 usual ductal hyperplasia, 76 ductal carcinoma in situ, and 198 BC specimens. The methylation status of RKIP was also determined in BC. In addition, the mRNA and protein level of RKIP was analyzed in 8 pairs of BC tissues and surrounding normal tissues by quantitative real-time polymerase chain reaction and Western blot analysis, respectively. RKIP mRNA and protein expression was significantly downregulated in BC tissues compared with the surrounding normal tissues (P<0.05 and P<0.01, respectively). Reduced RKIP expression seemed to increase progressively from normal breast to BC (P<0.001). Reduced RKIP expression was significantly associated with metastatic relapse (P<0.001) and was identified as an independent adverse prognostic indicator for disease-free survival (P=0.003). Reduced RKIP expression in BC was significantly correlated with its aberrant promoter methylation (P<0.05). In conclusion, downregulation of RKIP plays an important role in the breast neoplastic progression and correlates with poor prognosis in patients with BC. Aberrant RKIP methylation is one of the mechanisms that lead to downregulation of RKIP in BC. Copyright 2016 Wolters Kluwer Health, Inc. All rights reserved.


To reveal the linkage relationship between the Ms locus, a restorer-of-fertility gene for cytoplasmic male-sterility (CMS) caused by CMS-S cytoplasm in onion (Allium cepa L.) and previously reported molecular markers linked to the Ms locus, 11 recombinants selected from 4,273 segregating plants originating from the cross between male-sterile maternal and male-fertile paternal lines were analyzed. Results showed that genotypes of a codominant marker, jnurf12, were perfectly matched with the male-fertility phenotypes in all recombinants, but that this marker was not applicable in diverse breeding lines due to multiple band patterns. For the development of more reliable markers, a 12-bp indel was identified from the sequences which were obtained by genome walking, and was used to develop a simple PCR marker which was designated jnurf13. When 104 diverse breeding lines containing CMS-S cytoplasm were analyzed with the jnurf13 marker, male-fertility phenotypes of all breeding lines were perfectly matched with marker genotypes. To our surprise, phenotypes of 153 breeding lines containing CMS-T-like cytoplasm were also matched with genotypes of the jnurf13 marker which was linked to the Ms locus for the CMS-S system. Furthermore, phenotypes of four F2 populations containing CMS-T-like cytoplasm co-segregated perfectly with jnurf13 genotypes. Allelic segregation distortion was detected in two F2 populations using the jnurf13 maker. The results of this study were in conflict with a previous model for inheritance of fertility restoration in the CMS-T system. Therefore, we proposed a new model based on the data analyzed with the jnurf13 marker, which was in linkage disequilibrium with restorer-of-fertility genes for both CMS systems. © 2014 Springer Science+Business Media Dordrecht.


Lee K.R.,Chonnam National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2010

Lipomas are the most common benign tumors of adipose tissue among adults. Lipomas can occur almost anywhere in the trunk, extremities, mediastinum, and pelvis, but retroperitoneal lipomas are extremely rare. It should be distinguished from well differentiated liposarcoma in order to provide the appropriate treatment and follow up. We experienced a case of 60-year-old patient with large retroperitoneal lipoma mimicking liposarcoma causing palpable abdominal mass and pain. Abdominal computerized tomography (CT) showed 33 x 22 cm sized bulky fat-containing mass with contrast enhanced solid portion in right retroperitoneum. Positron emission tomograpgy (PET) revealed increased 18F-FDG uptake at solid portion shown in abdominal CT. Imaging studies confirmed a high index of suspicion on liposarcoma. Laparotomy showed a large encapsulating tumor arising from retroperitoneum with fat necrosis. Pathologic examination of resected specimen revealed normal mature adipocytes without atypical cells, compatible with lipoma.


Lee S.C.,Chung - Ang University | Luan S.,Chonnam National University | Luan S.,University of California at Berkeley
Plant, Cell and Environment | Year: 2012

Abscisic acid (ABA) regulates key processes relevant to seed germination, plant development, and biotic and abiotic stress responses. Abiotic stress conditions such as drought induce ABA biosynthesis initiating the signalling pathways that lead to a number of molecular and cellular responses, among which the best known are the expression of stress-related genes and stomatal closure. Stomatal closure also serves as a mechanism for pathogen defence, thereby acting as a platform for crosstalk between biotic and abiotic stress responses involving ABA action. Significant advances in our understanding of ABA signal transduction have been made with combination of approaches including genetics, biochemistry, electrophysiology and chemical genetics. Molecular components associated with the ABA signalling have been identified, and their relationship in the complex network of interactions is being dissected. We focused on the recent progress in ABA signal transduction, especially those studies related to identification of ABA receptors and downstream components that lead ABA signal to cellular response. In particular, we will describe a pathway model that starts with ABA binding to the PYR/PYL/RCAR family of receptors, followed by inactivation of 2C-type protein phosphatases and activation of SnRK2-type kinases, and eventually lead to activation of ion channels in guard cells and stomatal closure. Plants are constantly bombarded by environmental signals including both biotic and abiotic stress condtions. Among the complex molecular mechanisms for responding to these signals, plant hormone ABA plays a key role in the crosstalk of signaling pathways that couple biotic and abiotic signals to cellular responses. Centrally located in the many signaling processes, ABA-induced stomatal closure controls both pathogen entry and water loss during drought stress. This review highlights recent breakthroughs that demonstrate the molecular events underlying ABA action in stomatal guard cells. © 2011 Blackwell Publishing Ltd.


Yoon S.-D.,Chonnam National University
Journal of Agricultural and Food Chemistry | Year: 2014

The main objects of this study were to prepare the cross-linked potato starch/polyvinyl alcohol blend films with ascorbic acid (AsA) added as a plasticizer with and without heat curing and to examine their mechanical properties, elongation at break, degree of swelling, solubility, water vapor absorption, thermal properties, optical properties, and biodegradability. The specific surface area, pore volume, and topography of the films with and without heat curing were also investigated via nitrogen adsorption and desorption isotherms and atomic force microscopy analysis. The results indicate that the cured films possess mechanical, thermal, and optical properties enhanced compared to those of noncured films. The mechanical and water barrier properties of the AsA-added film were also found to be superior to those of other films with polyol plasticizers (glycerol and xylitol). The biodegradability test revealed that the prepared films are degraded by ∼35-80% after 165 days. © 2013 American Chemical Society.


Kim J.-N.,Korea Institute of Energy Research | Ko C.H.,Chonnam National University | Yi K.B.,Chungnam National University
International Journal of Hydrogen Energy | Year: 2013

Catalytic absorbents containing CaO and Ca12Al 14O33 and metallic Ni in one body were prepared in combination of precipitation and hydration and tested for sorption enhanced hydrogen production (SEHP). Adding aluminum precursor in the precipitation step induced the formation of Ca12Al14O33 and FIB-TEM analysis revealed that Ca12Al14O33 provides spacious pathway for CO2 diffusion by forming porous structure. In thermogravimetric analysis, Ca12Al14O 33 was identified as an excellent support material providing superior cyclic stability for Ca-based sorbent. Catalytic absorbents were prepared with adding various amount of Ni precursor (3, 5, 7, and 10 wt %). The SEHP test with the catalytic absorbents showed that 7wt% of Ni loading resulted in excellent performance in terms of H2 production and CH4 conversion. Ni agglomeration was observed when 10 wt% of Ni is loaded on the catalytic absorbent. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Park J.K.,Chonnam National University
Orthopedics | Year: 2010

This study evaluated and compared the intraoperative stabilities using the low and high femoral tunnel techniques in ACL reconstruction. Seventy patients who underwent ACL reconstruction were equally allocated to low or high femoral tunnel groups (35 in the low femoral tunnel group and 35 in the high femoral tunnel group) for this study. The authors compared intraoperative anterior, internal rotational, and external rotational stabilities at 0°, 30°, 60°, and 90° of knee flexion using a navigation system after reconstruction. The low femoral tunnel group showed significantly better intraoperative internal rotational stability at 0° and 30° of flexion than the high tunnel group; however, no significant intergroup differences were found for anterior and external rotational stabilities at any flexion angle. These findings suggested that the low femoral tunnel group showed better internal rotational stability at time zero condition during ACL reconstruction than the high femoral tunnel group, but anterior and external rotational stabilities were similar. However, to determine whether these results may affect clinical results, further studies based on more accurate measurement of rotational stability in clinical settings are needed. Copyright 2010, SLACK Incorporated.


Park S.Y.,Chonnam National University
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi | Year: 2010

Heparin and/or insulin stimulate lipoprotein lipase and are known to decrease serum triglyceride level. However, their efficacy in hypertriglyceridemia-induced acute pancreatitis in nondiabetic patients is not well documented. We report a case of hypertriglyceridemia-induced pancreatitis in 43-year-old nondiabetic woman in whom treatment with insulin was accompanied by reduction in serum triglyceride level and the resolution of pancreatitis. She presented to the emergency department with abdominal pain and biochemical evidence of acute pancreatitis. Her medical history was unremarkable. There was no history of alcohol consumption, and biliary imaging was not remarkable. Subsequent laboratory investigation revealed marked hypertriglyceridemia (1,951 mg/dL), impaired fasting glucose, and normal HbAlc level. The Ransons score and APATCH II score were 1 and 4. Abdominal CT showed diffuse enlargement of pancreas, peripancreatic fat infiltration, and multiple fluid collections around the pancreas. We treated the patient with the infusion of 5% dextrose and 1.5 unit/hr regular insulin to reduce serum triglyceride level. The level of serum triglyceride was decreased to 305 mg/dL on day 5. During the remainder of hospitalization, her clinical symptoms and laboratory values gradually improved.


Nguyen M.-K.,Nguyen Tat Thanh University | Lim Y.-C.,Chonnam National University | Kim Y.-J.,Chosun University
IEEE Transactions on Power Electronics | Year: 2012

A modified single-phase quasi-Z-source ac-ac converter is proposed in this paper. The proposed converter has the main features in that the output voltage can be bucked or boosted and be both in-phase and out-of-phase with the input voltage. The input voltage and output voltage share the same ground, the size of a converter is reduced, and it operates in a continuous current mode. A safe-commutation strategy for the modified single-phase quasi-Z-source ac-ac converter is used instead of a snubber circuit. The operating principles and a steady-state analysis are presented. A laboratory prototype, tested using a resistive load, a passive load, and a nonlinear load, was constructed that used an input voltage of 70 V$ \rm rms /60Hz in order to verify the performance of the modified single-phase quasi-Z-source ac-ac converter. The experimental results verified that the converter has a lower input current total harmonic distortion, a higher input power factor, and a higher efficiency in comparison to a conventional single-phase Z-source ac-ac converter. In addition, the experimental results show that the use of the safe-commutation strategy is a significant improvement, as it makes it possible to avoid voltage spikes on the switches. © 2011 IEEE.


There are two surgical approaches for distal soft-tissue procedures for the correction of hallux valgus-the dorsal first web-space approach, and the medial transarticular approach. The purpose of this study was to compare the outcomes achieved after use of either of these approaches combined with a distal chevron osteotomy in patients with moderate to severe hallux valgus. One hundred and twenty-two female patients (122 feet) who underwent a distal chevron osteotomy as part of a distal soft-tissue procedure for the treatment of symptomatic unilateral moderate to severe hallux valgus constituted the study cohort. The 122 feet were randomly divided into two groups: namely, a dorsal first web-space approach (group D; sixty feet) and a medial transarticular approach (group M; sixty-two feet). The clinical and radiographic results of the two groups were compared at a mean follow-up time of thirty-eight months. The American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scale hallux metatarsophalangeal-interphalangeal scores improved from a mean and standard deviation of 55.5 ± 12.8 points preoperatively to 93.5 ± 6.3 points at the final follow-up in group D and from 54.9 ± 12.6 points preoperatively to 93.6 ± 6.2 points at the final follow-up in group M. The mean hallux valgus angle in groups D and M was reduced from 32.2° ± 6.3° and 33.1° ± 8.4° preoperatively to 10.5° ± 5.5° and 9.9° ± 5.5°, respectively, at the time of final follow-up. The mean first intermetatarsal angle in groups D and M was reduced from 15.0° ± 2.8° and 15.3° ± 2.7° preoperatively to 6.5° ± 2.2° and 6.3° ± 2.4°, respectively, at the final follow-up. The clinical and radiographic outcomes were not significantly different between the two groups. The final clinical and radiographic outcomes between the two approaches for distal soft-tissue procedures were comparable and equally successful. Accordingly, the results of this study suggest that the medial transarticular approach is an effective and reliable means of lateral soft-tissue release compared with the dorsal first web-space approach. Therapeutic level II. See Instructions for Authors for a complete description of levels of evidence.


Lee S.-H.,Chonnam National University | Park S.-H.,Seoul National University | Kim J.-S.,Seoul National University | Kim H.-J.,Seoul National University | And 3 more authors.
Annals of Neurology | Year: 2014

The oculomotor abnormalities with isolated infarction of the cerebellar tonsil are unknown. In a patient with acute infarction of the right tonsil, we found (1) nearly completely abolished ipsilateral smooth pursuit and impaired contralateral pursuit, (2) a low-amplitude ipsilesional right-beating nystagmus without fixation, (3) gaze-holding deficits, and (4) normal vestibulo-ocular reflex. These findings contrast with striking vestibular abnormalities reported with unilateral flocculus and anterior tonsil infarction. Taken together, these findings allow more diagnostic certainty in cerebellar patients, help resolve controversies about interpretation of experimental findings in monkeys, and clarify homologies between the monkey and human cerebellum. Ann Neurol 2014;75:429-434 © 2014 Child Neurology Society/American Neurological Association.


Jeon T.-I.,Sanford Burnham Institute for Medical Research | Jeon T.-I.,Chonnam National University | Esquejo R.M.,Sanford Burnham Institute for Medical Research | Roqueta-Rivera M.,Sanford Burnham Institute for Medical Research | And 5 more authors.
Cell Metabolism | Year: 2013

Sterol regulatory element-binding proteins (SREBPs) have evolved as a focal point for linking lipid synthesis with other pathways that regulate cell growth and survival. Here, we have uncovered a polycistrionic microRNA (miRNA) locus that is activated directly by SREBP-2. Two of the encoded miRNAs, miR-182 and miR-96, negatively regulate the expression of Fbxw7 and Insig-2, respectively, and both are known to negatively affect nuclear SREBP accumulation. Direct manipulation of this miRNA pathway alters nuclear SREBP levels and endogenous lipid synthesis. Thus, we have uncovered a mechanism for the regulation of intracellular lipid metabolism mediated by the concerted action of a pair of miRNAs that are expressed from the same SREBP-2-regulated miRNA locus, and each targets a different protein of the multistep pathway that regulates SREBP function. These studies reveal an miRNA "operon" analogous to the classic model for genetic control in bacterial regulatory systems. © 2013 Elsevier Inc.


Park J.-Y.,Sejong University | Song S.-J.,Chonnam National University | Wachsman E.D.,University of Florida
Journal of the American Ceramic Society | Year: 2010

Miniature, potentiometric, solid-state CO sensors utilizing titania-based semiconducting oxide electrodes are studied at the operating temperature of the optimal response, i.e., 500°C. To improve the selectivity, sensitivity, and response time, yttria and palladium were mixed into the titania electrodes. Excellent sensing performance was obtained using an assembly of titania on one side and composite titania cermet synthesized by adding yttria and palladium on the other. The use of platinum contacts instead of gold current collectors afforded a substantial improvement in voltage response. The device detected an extended range of CO concentration (1-1000 ppm) with a high sensitivity to CO, while being capable of detecting even 1 ppm variations at low CO concentration ranges and retaining considerable selectivity to CO against CO2, NO, and O2 gases. Additionally, the response to CO is barely influenced by the coexisting interference gases (100 ppm NO, 16% CO2, 3% O 2, 3% H2O). © 2009 The American Ceramic Society.


Kim C.H.,Chonnam National University | Kim B.-H.,Daegu University
Journal of Power Sources | Year: 2015

ZnO-containing porous activated carbon nanofibers (ZnO/ACNFs) are prepared through one-step electrospinning using zinc acetate and polyacrylonitrile (PAN), followed by thermal treatment. The electrochemical performance of the ZnO/ACNF composite electrodes is compared to that of pure ACNF electrodes in aqueous KOH as the electrolyte. Electrochemical measurements of ZnO/ACNFs reveal a maximum specific capacitance of 178.2 Fg-1, and high energy densities of 22.71-17.77 Whkg-1 in the power density range of 400 to 4000 W kg-1. Furthermore, this supercapacitor electrode exhibits excellent cycle life with a specific capacitance ∼75% of the initial value after 1000 cycles. The combination of ACNF's high surface area with ZnO's large specific capacity facilitates a synergistic effect between ZnO's faradaic capacitance and ACNF's double layer capacitance, which afforded good capacitive behavior. © 2014 Elsevier B.V. All rights reserved.


Cho H.-S.,Harvard University | Lee K.,Chonnam National University
Materials Characterization | Year: 2012

A comprehensive understanding of the formation of the sigma phase resulting from the eutectoid reaction (δ→σ+γ 2) is required. The kinetics necessary for the eutectoid reaction are closely related to the amount of plastic deformation in DSS. This work investigates the microstructural evolution of the σ phase in a 22Cr-5Ni SAF 2205 DSS after subsequent plastic deformation and isothermal aging. The precipitation of the σ phase resulted from the higher driving force for precipitating intermetallic compounds and the higher diffusion rate of their elements by cold-rolling, as well as the sufficient supply of molybdenum. The maximum amount of σ phase precipitation remarkably increased with an increasing cold deformation, as compared with the non-cold-rolled materials. © 2012 Elsevier Inc.


Lee K.S.,Chonnam National University
Journal of Advanced Concrete Technology | Year: 2010

Lateral-load resisting systems of many low-rise reinforced concrete (RC) buildings are composed of members that may be vulnerable to pre-emptive shear failures, depending on whether their shear strengths are sufficient to develop their flexural strengths (referred to as dual lateral-load resisting system, subsequently); therefore the buildings have a lateral strength associated with the strengths of the components, and the component strengths may be governed by both shear and flexure (the component strengths are referred to as shear and flexural strengths, subsequently). At present there is no effective ways to assess the component strength and ductility of a RC building having a dual lateral-load resisting system. This paper presents a method for determining required shear and flexural strengths associated with structural damage states for various levels of earthquake demand of low-rise RC buildings having a dual lateral-load resisting system. The interaction curves of the required strengths are derived for various ductility ratios based on nonlinear dynamic analyses of the single-degree-of-freedom system. The structural damage states of RC buildings controlled by both shear and flexure are evaluated in terms of the ductility ratio by the procedure outlined by the Japanese Standard. The proposed method predicts reasonably well damage sustained by actual buildings during an earthquake. The proposed method can be used to develop performance-based seismic evaluation and rehabilitation procedures of low-rise RC buildings having a dual lateral-load resisting system. © 2010 Japan Concrete Institute.


Cheong S.H.,Chonnam National University
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2016

This study sought to prepare calcium lactate using precipitated calcium carbonate (PCC) by reacting lactic acid and then investigated the formation yield and physicochemical properties of synthetic calcium lactate by Fourier Transform Infrared Spectroscopy (FT -IR), Thermogravimetric-Differential Thermal Analysis (TG-DTA) and Scanning Electron Microscope (SEM). The strong OH valence band of calcium lactate prepared by PCC in the 3000~3500 cm -1 region of the FT-IR spectra showed very low intensity. Also it was found that the characteristic carbonyl band was observed at approximately 1500~1750 cm -1 (C=O stretching) and 1300~1400 cm -1 (C-H bending), respectively. The diffraction profile of synthetic calcium lactate prepared by PCC showed a typical diffraction pattern for a crystalline solid. The TG-DTA curve of calcium lactate showed a rapid decrease at 200~400 °C due to the melting point of calcium lactate, which was about 240 °C. In particular, the curve had a second decrease at 600~800 °C due to the decarbonation of calcium oxide. As for SEM images, calcium lactate using PCC existed as plate-like crystals with smooth surface. These results indicated that calcium lactate pentahydrate was formed by reacting between PCC and lactic acid.


Cho J.T.,Chonnam National University
International Journal of Geometric Methods in Modern Physics | Year: 2013

A Kenmotsu 3-manifold M admitting a Ricci soliton (g, w) with a transversal potential vector field w (orthogonal to the Reeb vector field) is of constant sectional curvature -1. A cosymplectic 3-manifold admitting a Ricci soliton with the Reeb potential vector field or a transversal vector field is of constant sectional curvature 0. © 2013 World Scientific Publishing Company. © 2013 World Scientific Publishing Company.


Park S.H.,Chonnam National University | Yoon S.H.,Korea Advanced Institute of Science and Technology
Applied Energy | Year: 2015

The ultimate purpose of this study is the reduction of exhaust emissions from a dimethyl ether (DME) fueled diesel engine without deterioration of engine performance, such as indicated mean effective pressure (IMEP) and indicated specific fuel consumption (ISFC). In this study, we applied multiple injection strategies to achieve the research goal. In a comparison between diesel and DME single injection combustion, the IMEP in both fuels was similar around the top dead center (TDC) injection condition (this is the typical injection timing). However, the nitrogen oxide (NOx) emission in DME was higher than that in diesel. The single injection combustion in DME and diesel was compared on the basis of the same energy input condition. When the injection timing was advanced in order to reduce the DME NOx emission, the IMEP in DME decreased below the diesel level. Therefore, multiple injection strategies, including pilot injection, split injection, and advanced+post injection, were applied in this study. In the experimental results, the pilot injection strategy with advanced main injection (2nd injection) resulted in the lowest NOx, HC, and CO emissions. In the case of soot emission, DME itself has soot free combustion, and emitted an ignorable amount of soot. Moreover, the pilot injection strategy showed the highest IMEP level and the lowest ISFC level in the test conditions. © 2015 Elsevier Ltd.


Jha M.K.,Kyungpook National University | Lee S.,Kyungpook National University | Lee S.,Korea Brain Research Institute | Park D.H.,Kyungpook National University | And 4 more authors.
Neuroscience and Biobehavioral Reviews | Year: 2015

Lipocalin-2 (LCN2) is an acute phase protein with multiple functions that has garnered a great deal of interest over the last decade. However, its precise role in the pathophysiology of the central nervous system (CNS) remains to be outlined. Emerging evidence indicates that LCN2 is synthesized and secreted as an inducible factor from activated microglia, reactive astrocytes, neurons, and endothelial cells in response to inflammatory, infectious, or injurious insults. More recently, it has been recognized as a modulatory factor for diverse cellular phenotypes in the CNS, such as cell death, survival, morphology, migration, invasion, differentiation, and functional polarization. LCN2 induces chemokine production in the CNS in response to inflammatory challenges, and actively participates in the innate immune response, cellular influx of iron, and regulation of neuroinflammation and neurodegeneration. LCN2 also modulates several biobehavioral responses including pain hypersensitivity, cognitive functions, emotional behaviors, depression, neuronal excitability, and anxiety. This review covers recent advances in our knowledge regarding functional roles of LCN2 in the CNS, and discusses how LCN2 acts as an autocrine mediator of astrocytosis, a chemokine inducer, and a modulator of various cellular phenotypes in the CNS. We finally explore the possibilities and challenges of employing LCN2 as a signature of several CNS anomalies. © 2014 Elsevier Ltd.


Kim Y.-W.,Chonnam National University
Acta Mechanica Sinica/Lixue Xuebao | Year: 2015

Abstract: The free vibration characteristics of fluid-filled functionally graded cylindrical shells buried partially in elastic foundations are investigated by an analytical method. The elastic foundation of partial axial and angular dimensions is represented by the Pasternak model. The motion of the shells is represented by the first-order shear deformation theory to account for rotary inertia and transverse shear strains. The functionally graded cylindrical shells are composed of stainless steel and silicon nitride. Material properties vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The governing equation is obtained using the Rayleigh–Ritz method and a variation approach. The fluid is described by the classical potential flow theory. Numerical examples are presented and compared with existing available results to validate the present method. Graphical Abstract: The free vibration of fluid-filled functionally graded cylindrical shells buried partially in elastic foundations is investigated by an analytical method. The elastic foundation of partial axial and angular dimensions is represented by the Pasternak model. Shell motion is represented by first-order shear deformation theory. The governing equation is obtained using the Rayleigh–Ritz method. The fluid is described by classical potential flow theory. Numerical examples are presented and compared with existing available results to validate the present method. [Figure not available: see fulltext.] © 2015 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg


Noh H.-R.,Chonnam National University | Moon H.S.,Pusan National University
Optics Express | Year: 2011

We present discrimination of the effect of one-photon and two-photon coherences in electromagnetically induced transparency for a three-level ladder-type atomic system. After the optical Bloch equations for a three-level atom, with either cycling or non-cycling transitions, were solved numerically, the solutions were averaged over the velocity distribution and finite transit time. Through this we were able to discriminate one-photon and two-photon coherence parts of the calculated spectra. We also found that the spectra showed peaks as the branching ratio of the intermediate (excited) state increased (decreased). The experimental results of previous reports [H. S. Moon, et al., Opt. Express 16, 12163 (2008); H. S. Moon and H. R. Noh, J. Phys. B 44, 055004 (2011)] could well be accounted for by this discrimination of one-photon and two-photon coherences in the transmittance signals for the simplified three-level atomic system. © 2011 Optical Society of America.


Kim S.,Chonnam National University
Journal of Engineered Fibers and Fabrics | Year: 2011

An integrated woven fabric system has been developed. A series of parametric design rules have been defined by analyzing famous woven structures. An expandable script language and its compiler have been developed to generate scalable weave diagrams using those rules. A calculation algorithm has also been developed to generate draft and peg plans based on the weave diagrams. Finally, a two-dimensional realistic fabric image rendering function using the actual image of various yarns, a three-dimensional fabric modeling method based on B-Spline approximation, and a pseudo three-dimensional mapping method for simulated images of final products were all integrated into the system.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

In the title complex, [Pt(C6H4NO2) Cl(C2H6OS)], the PtII ion is in a distorted square-planar environment defined by the N and O atoms from the chelating pyridine-2-carboxyl-ate (pic) anionic ligand, one S atom of the dimethyl sulfoxide mol-ecule and one Cl ion. The complex is disposed about a crystallographic mirror plane parallel to the ac plane passing through all the atoms of the complex except the methyl atoms of the dimethyl sulfoxide. The mol-ecules are stacked in columns along the b axis with a Pt⋯Pt distance of 4.9508 (5) Å. Within the column, inter-molecular C - H⋯O hydrogen bonds and weak π-π inter-actions between adjacent pyridine rings are present, the shortest centroid-centroid distance being 5.153 (4) Å.


Noh H.-R.,Chonnam National University | Jhe W.,Seoul National University
Optics Communications | Year: 2010

We present analytic solutions of optical Bloch equations. We found that the solutions exhibit two different types of the behavior: one is oscillatory, and the other is a simple decay. The boundary dividing the two different types of solutions is exactly calculated in a two-dimensional space of the laser detuning and Rabi frequency. We also obtained simple analytic solutions for special conditions. © 2010 Elsevier B.V. All rights reserved.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

The asymmetric unit of the title compound, (C13H 10N)2[PtCl6]·2H2O, contains a protonated acridine cation, one half of a [PtCl6]2- dianionic complex and a solvent water mol-ecule. The octa-hedral [PtCl 6]2- dianion is located on an inversion centre. π-π inter-actions between neighboring acridinium cations produce stacks along the a axis; the shortest distance between the centroids of the six-membered rings within the cations is 3.553 (9) Å. In the crystal, two independent inter-molecular O - H⋯Cl hydrogen bonds, both involving the same Cl atom of the anion as acceptor, give rise to chains also running along the a axis; in addition each water mol-ecule, as a hydrogen-bond acceptor, is linked to the acridinium N - H group.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

In the title complex, [PdBr2(C12H8N2)], the PdII ion is four-coordinated in a slightly distorted square-planar environment by two N atoms of the chelating 1,10-phenanthroline ligand and two bromide ions. The complex displays numerous inter-molecular π-π inter-actions between adjacent six-membered rings, the shortest centroid-centroid distance being 3.680 (4) Å. The nearly planar [maximum deviation 0.143 (2) Å] mol-ecules stack in columns parallel to (101) with a Pd⋯Pd distance of 4.8466 (9) Å.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

The asymmetric unit of the title compound, (C12H 9N2)2[PtBr6]·2H2O, contains a protonated 1,10-phenanthroline cation (H-phen), one half of a [PtBr6]2- anionic complex and a solvent water molecule. The PtIV ion is located on an inversion centre and is coordinated in an octa-hedral environment by six Br atoms. The crystal structure displays numerous inter-molecular π-π interactions between six-membered rings of H-phen, with a shortest centroid-centroid distance of 3.670 (5) Å, and inter-molecular N - H⋯O, O - H⋯Br and O - H⋯N hydrogen bonds.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

The asymmetric unit of the title compound, (C13H 10N)2[Pt(NCS)4], contains a protonated acridine molecule and one half of a [Pt(NCS)4]2- anion. In the complex anion, the PtII ion is located on an inversion centre and is four-coordinated in a slightly distorted square-planar environment by four S atoms from four thio-cyanate ligands. The compound displays numerous inter-molecular π-π interactions between six-membered rings, with a shortest centroid-centroid distance of 3.682 (3) Å. The component ions inter-act by means of inter-molecular N - H⋯N hydrogen bonds.


Cho S.T.,Hallym University | Jung S.I.,Chonnam National University | Myung S.C.,Chung - Ang University | Kim T.H.,Chung - Ang University
International Journal of Urology | Year: 2013

Objective: To determine the correlation between metabolic syndrome and the distribution of stone components in patients with urolithiasis. Methods: Between January 2007 and December 2010, renal or ureteral stones were collected from 712 patients (432 males, 280 females) who underwent surgical intervention at three hospitals in South Korea. Metabolic syndrome was defined according to the latest definition of the International Diabetes Federation, using ethnicity- and sex-specific cut-off values for central obesity. Patients were assessed by factors used in metabolic syndrome. All urinary stones were analyzed using infrared spectrophotometry and categorized according to their main component. Results: The patients' mean age was 55.9 years (range 19-93 years). Of the 712 patients, 347 (48.7%; 205 males, 142 females) had a diagnosis of metabolic syndrome. Calcium oxalate (71.5%), uric acid (15.3%), carbonate apatite (8.0%) and struvite (4.1%) calculi were found as the main stone components. Overall, the proportion of uric acid calculi was markedly higher in patients with rather than without metabolic syndrome (19.6 vs 11.2%; P=0.002). However, the proportion of calcium oxalate, carbonate apatite and struvite calculi did not differ between the two groups. The multivariable-adjusted odds ratio for uric acid calculi according to the metabolic syndrome components indicated that the presence of metabolic syndrome was associated with a 93% increased odds ratio of uric acid calculi compared with the absence of metabolic syndrome. Impaired fasting glucose and hypertriglyceridemia were independent risk factors for uric acid calculi. Conclusions: Metabolic syndrome is associated with a significantly increased risk of uric acid calculi development, especially those with impaired fasting glucose and hypertriglyceridemia. © 2012 The Japanese Urological Association.


This study was conducted to examine the role of child depression in the relations between deficits in competence and aggression by replicating and extending the study by Cole et al.(1996). In a two-wave longitudinal study, 6th-grade children (n = 329) completed self-report measures of three domains of competence (i.e. social, academic, behavioural), depression and aggression. Parents also reported information about their child's competence in the three domains, depression and aggression. The participants were all residents in lower-middle- to middle-class urban areas in a large southwestern city of Korea. Data were collected through paper/pencil questionnaires administered twice during the school year (near the end of the first and second semesters in 2008) approximately 6 months apart. Hierarchical regression analyses were implemented to examine whether Wave 2 depression moderates or mediates the relations between deficits in Wave 1 competence and Wave 2 aggression. To take account of the domain-specificity of child competence, separate hierarchical regression analyses for the three domains of competence were conducted. Self-reports and parent reports for each variable were standardized and combined into a composite index. The results of the hierarchical regression analyses were summarized as follows. First, depression did not moderate the relations between deficits in competence and aggression. Second, depression served as a mediator only in the relation between deficits in behavioural competence and aggression. In contrast, depression did not mediate the relation between lowered social or academic competence and aggression. The findings of this study provide partial evidence for the competence-based model of childhood depression and for the role of depression as a trigger of aggressive behaviours among children who lack in behavioural competence. The results imply that school psychologists and school counsellors should not overlook deficits in behavioural competence and depression among aggressive children while providing screening and intervention services for these children. © 2010 SAGE Publications.


Shim W.G.,Chonnam National University | Kim S.C.,Mokpo National University
Applied Surface Science | Year: 2010

The heterogeneous adsorption and catalytic oxidation of benzene, toluene and o-xylene (BTX) over the spent platinum catalyst supported on activated carbon (Pt/AC) as well as the chemically treated spent catalysts were studied to understand their catalytic and adsorption activities. Sulfuric aqueous acid solution (0.1N, H2SO4) was used to regenerate the spent Pt/AC catalyst. The physico-chemical properties of the catalysts in the spent and chemically treated states were analyzed by using nitrogen adsorption-desorption isotherm and elemental analysis (EDX). The gravimetric adsorption and the light-off curve analysis were employed to study the BTX adsorption and oxidation on the spent catalyst and its modified Pt/AC catalysts. The experimental results indicate that the spent Pt/AC catalyst treated with the H2SO4 aqueous solution has a higher toluene adsorption and conversion ability than that of the spent Pt/AC catalyst. A further studies of H2SO4 treated Pt/AC catalyst on their catalytic and heterogeneous adsorption behaviours for BTX revealed that the activity of the H2SO4 treated Pt/AC catalyst follows the sequence of benzene > toluene > o-xylene. The adsorption equilibrium isotherms of BTX on the H2SO4 treated Pt/AC were measured at different temperatures ranging from 120 to 180 °C. To correlate the equilibrium data and evaluate their adsorption affinity for BTX, the two sites localized Langmuir (L2m) isotherm model was employed. The heterogeneous surface feature of the H2SO4 treated Pt/AC was described in detail with the information obtained from the results of isosteric enthalpy of adsorption and adsorption energy distributions. Furthermore, the activity of H2SO4 treated Pt/AC about BTX was found to be directly related to the Henry's constant, isosteric enthalpy of adsorption and adsorption energy distribution functions. © 2009 Elsevier B.V. All rights reserved.


Jung S.,Chonnam National University
International Journal of Energy Research | Year: 2016

Electrode morphology has significant influence on the performance of lithium-ion batteries in that it controls electrical conductivity and electrode utilization by establishing electrical connectivity in the electrode. The present study investigates the effect of the electrode morphology on battery performance by combining two different mathematical models. First, a two-dimensional, direct numerical simulation (DNS) model is introduced, which stochastically generates electrode morphology and calculates electrical conduction and electrode utilization. Various simulations are conducted to evaluate the effect of the active particle coating, conductive agent loading, particle size, and electrode compression by using the DNS model. Second, data acquired from the DNS model are applied to the blended-electrode model to evaluate battery performance. Calculation result confirms that electrode morphologies have significant effects on both capacity and power of lithium-ion batteries. © 2016 John Wiley & Sons, Ltd.


Choi Y.,Chonnam National University
Journal of Infrared, Millimeter, and Terahertz Waves | Year: 2015

For multi-gigabit wireless transmission in fiber-wireless (FiWi) networks, one of the good promising candidates is terahertz (THz) communications. In order to analyze the performance of THz communication systems, where there exist multiple paths caused by THz signal’s reflections, a proper channel model for describing the THz frequency characteristics and an adequate path selection algorithm is important. By bringing the blocking probability to describe the blocking effect of the propagation signals, this paper provides a modified THz channel model and proposes a path selection algorithm for finding the dominant signal. This paper also analyzes the correlation coefficient between propagation signals. Numerical results reveal that the modified channel model is suitable for describing the blocking effect of the propagation signals in the FiWi indoor environment and the proposed algorithm makes use of path diversity well to achieve the highest data transmission rate. © 2015 Springer Science+Business Media New York


Sheen D.-H.,Chonnam National University
Bulletin of the Seismological Society of America | Year: 2015

This study proposes a robust method that estimates a reliable earthquake location from only a small number of P-wave arrival times. The method is based on the maximum-likelihood estimation from differential P-wave arrivals. We formulate the problem using a probability density function (PDF) of the residual between observed and predicted differential P-wave travel times between two seismic stations and construct the likelihood function from the sum of the products of the independent PDFs. The hypocenter is determined by an iterative grid-search algorithm that finds the point with the largest probability on successively finer grids. To reduce the effect from outliers possibly concealed within a small number of observations, the Student’s t-distribution is used for the PDF of the location likelihood. The jackknife resampling technique is also used to discriminate outliers from the observations. The robustness of the method is tested using the Monte Carlo experiments that locate 10,000 events from small numbers of P-wave arrivals observed within an epicentral distance of 100 km, including both arrival-time error and velocity-model error. The earthquakes are located within an epicentral distance of 8:5 10:8 km and 20:6 33:1 km for events inside the seismic network and outside the network, respectively, using only five P-wave arrivals, including a large arrival-time error between 1 and 5 s. This shows that this method can estimate the location of the event reliably with only a few P-wave arrivals, even when contaminated by an outlier. Therefore, it is believed that this location method could significantly improve the robustness of an earthquake early warning system. © 2015, Seismological Society of America. All rights reserved.


Kwon O.S.,Seoul National University | Park S.J.,Seoul National University | Yoon H.,Chonnam National University | Jang J.,Seoul National University
Chemical Communications | Year: 2012

Multidimensional polypyrrole nanotubes (MPPy NTs) were successfully fabricated as chemiresistors on a sacrificial nanofiber template by vapor deposition polymerization (VDP) and used to discriminate volatile organic compounds (VOCs) and toxic gases. © 2012 The Royal Society of Chemistry.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

In the title complex, [PtBr4(C10H8N 2)], the PtIV ion has a slightly distorted octa-hedral coordination defined by two N atoms of the chelating 2,2′-bipyridine ligand and four bromide ions. As a result of the different trans effects of the N and Br atoms, the Pt - Br bonds trans to the N atom are slightly shorter than those to mutually trans Br atoms. In the crystal structure, the molecules are arranged in a V-shaped packing pattern along the b axis and stacked in columns along the a axis. In the columns, several inter-molecular π-π interactions between the pyridine rings are present. The shortest ring centroid-centroid distance is 3.921 (6) Å, with a dihedral angle of 1.6 (5)° between the ring planes. The complexes are connected by C - H⋯Br hydrogen bonds, forming chains along the b axis.


Noh H.-R.,Chonnam National University
Journal of the Optical Society of America B: Optical Physics | Year: 2016

We present a theoretical study of polarization spectroscopy (PS) for the Jg 0 Je 1 transition. An analytical form of the line shape in PS is obtained in the Doppler-broadened limit up to the first (arbitrary) order of the Rabi frequency of the probe (pump) beam; this shape is influenced by the coherent effect resulting from nonlinear interactions between laser beams via atoms. The analytical solutions of the slope at the resonance and amplitude of the line shape in PS also are obtained. © 2016 Optical Society of America.


Aravindan V.,Nanyang Technological University | Gnanaraj J.,Yardney Technical Products, Inc. | Lee Y.-S.,Chonnam National University | Madhavi S.,Nanyang Technological University
Journal of Materials Chemistry A | Year: 2013

Development of an eco-friendly, low cost and high energy density (∼700 W h kg-1) LiMnPO4 cathode material became attractive due to its high operating voltage ∼4.1 V vs. Li falling within the electrochemical stability window of conventional electrolyte solutions and offers more safety features due to the presence of a strong P-O covalent bond. The vacancy formation energy for LiMnPO4 was 0.19 eV higher than that for LiFePO4, resulting in a 10-3 times-diluted complex concentration, which represents the main difference between the kinetics in the initial stage of charging of two olivine materials. This review highlights the overview of current research activities on LiMnPO4 cathodes in both native and substituted forms along with carbon coating synthesized by various synthetic techniques. Further, carbon coated LiMnPO4 was also prepared by a solid-state approach and the obtained results are compared with previous literature values. The challenges and the need for further research to realize the full performance of LiMnPO4 cathodes are described in detail. © 2013 The Royal Society of Chemistry.


Gaass M.,University of Regensburg | Huttel A.K.,University of Regensburg | Kang K.,University of Regensburg | Kang K.,Chonnam National University | And 4 more authors.
Physical Review Letters | Year: 2011

We investigate quantum dots in clean single-wall carbon nanotubes with ferromagnetic PdNi-leads in the Kondo regime. Most of the Kondo resonances exhibit a splitting, which depends on the tunnel coupling to the leads and an external magnetic field B, but only weakly on the gate voltage. Using numerical renormalization group calculations, we demonstrate that all salient features of the data can be understood using a simple model for the magnetic properties of the leads. The magnetoconductance at zero bias and low temperature depends in a universal way on gμ B(B-B c)/k BT K, where T K is the Kondo temperature and B c the external field compensating the splitting. © 2011 American Physical Society.


Kim Y.-J.,Massachusetts Institute of Technology | Ahn S.-J.,Chonnam National University | Hwang P.-I.,Seoul National University | Pyo G.-C.,Seoul National University | Moon S.-I.,Seoul National University
IEEE Transactions on Power Systems | Year: 2013

This paper presents a new control method, in which a distributed generator (DG) actively participates in steady-state voltage control, together with an under-load tap changer (ULTC) and shunt capacitors (Sh.Cs). In the conventional DG control method, the integration of DGs into a distribution power system increases the number of switching operations of the ULTC and the Sh.Cs. To solve this problem, this paper proposes that the DG output voltage be dispatched cooperatively with the operation of the ULTC and the Sh.Cs, based on load forecasts for one day in advance. The objective of the proposed method is to decrease the number of switching device operations, as well as to reduce the power loss in the distribution lines, while maintaining the grid voltage within the allowed range. The proposed method is designed and implemented with Matlab, using two different dynamic programming algorithms for a dispatchable and a nondispatchable DG, respectively. Simulation studies demonstrate that the objective can be achieved under various grid conditions, determined by factors such as the DG output power characteristics, the location of the DG-connected bus on the feeder, and the load profile of the feeder containing the DG. © 2012 IEEE.


Shim H.J.,Chonnam National University
World Journal of Hepatology | Year: 2010

Tertiary syphilis, especially in cases involving visceral gummatous disease, can be confused with cancer of the solid organs. We report a case of tertiary hepatic syphilis that manifested with intrahepatic masses in a patient who had an underlying primary peritoneal serous carcinoma (PPSC). The patient was diagnosed with PPSC and achieved a complete remission of PPSC following six cycles of platinum-based chemotherapy. Two hepatic nodules developed during the follow-up period and were initially labeled as hepatic metastases from the underlying PPSC, based on radiological findings. A resection of hepatic nodules was performed for therapeutic and diagnostic purposes, because there were no other metastatic foci except in the liver. Unexpectedly, serology and histology confirmed tertiary syphilis. This rare case emphasizes the importance of including tertiary syphilis in the differential diagnosis of a space-occupying lesion, even with an existing diagnosis of underlying cancer. © 2010 Baishideng.


Yun J.W.,Chonnam National University
Plasma Science and Technology | Year: 2013

To reduce time and energy during thermal binder removal in the ceramic process, plasma surface treatment was applied before the lamination process. The adhesion strength in the lamination films was enhanced by oxidative plasma treatment of the porous green ceramic film with polymeric binding materials. The oxygen plasma characteristics were investigated through experimental parameters and weight loss analysis. The experimental results revealed the need for parameter analysis, including gas material, process time, flow rate, and discharge power, and supported a mechanism consisting of competing ablation and deposition processes. The weight loss analysis was conducted for cyclic plasma treatment rather than continuous plasma treatment for the purpose of improving the film's permeability by suppressing deposition of the ablated species. The cyclic plasma treatment improved the permeability compared to the continuous plasma treatment.


Noh H.-R.,Chonnam National University
Journal of the Optical Society of Korea | Year: 2013

This work presents a theoretical study on the analytical calculation of the lineshape of polarization spectroscopy (PS) for the transition line 5s2 1S0 → 5s5p 1P1 of 88Sr. From the obtained analytical form of the PS spectrum, we were able to identify how the saturation affected the lineshape of the PS spectrum. The results obtained will be useful for polarization spectroscopy experiments using the alkaline-earth atoms such as Sr or Yb.


Kim H.,Seoul National University | Cho M.-Y.,Korea Institute of Ceramic Engineering And Technology | Kim M.-H.,Korea Institute of Ceramic Engineering And Technology | Park K.-Y.,Seoul National University | And 4 more authors.
Advanced Energy Materials | Year: 2013

A hybrid supercapacitor with high energy and power densities is reported. It comprises a composite anode of anatase TiO2 and reduced graphene oxide and an activated carbon cathode in a non-aqueous electrolyte. While intercalation compounds can provide high energy typically at the expense of power, the anatase TiO2 nanoparticles are able to sustain both high energy and power in the hybrid supercapacitor. At a voltage range from 1.0 to 3.0 V, 42 W h kg-1 of energy is achieved at 800 W kg-1. Even at a 4-s charge/discharge rate, an energy density as high as 8.9 W h kg-1 can be retained. The high energy and power of this hybrid supercapacitor bridges the gap between conventional batteries with high energy and low power and supercapacitors with high power and low energy. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lee Y.S.,Massachusetts Institute of Technology | Heo J.,Harvard University | Heo J.,Chonnam National University | Siah S.C.,Massachusetts Institute of Technology | And 5 more authors.
Energy and Environmental Science | Year: 2013

We demonstrate a tunable electron-blocking layer to enhance the performance of an Earth-abundant metal-oxide solar-cell material. A 5 nm thick amorphous ternary metal-oxide buffer layer reduces interface recombination, resulting in sizable open-circuit voltage and efficiency enhancements. This work emphasizes the importance of interface engineering in improving the performance of Earth-abundant solar cells. © The Royal Society of Chemistry 2013.


Kim Y.-J.,Kyung Hee University | Lee O.R.,Chonnam National University | Oh J.Y.,Kyung Hee University | Jang M.-G.,Kyung Hee University | Yang D.-C.,Kyung Hee University
Plant Physiology | Year: 2014

Ginsenosides are glycosylated triterpenes that are considered to be important pharmaceutically active components of the ginseng (Panax ginseng 'Meyer') plant, which is known as an adaptogenic herb. However, the regulatory mechanism underlying the biosynthesis of triterpene saponin through the mevalonate pathway in ginseng remains unclear. In this study, we characterized the role of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) concerning ginsenoside biosynthesis. Through analysis of full-length complementary DNA, two forms of ginseng HMGR (PgHMGR1 and PgHMGR2) were identified as showing high sequence identity. The steady-state mRNA expression patterns of PgHMGR1 and PgHMGR2 are relatively low in seed, leaf, stem, and flower, but stronger in the petiole of seedling and root. The transcripts of PgHMGR1 were relatively constant in 3- and 6-year-old ginseng roots. However, PgHMGR2 was increased five times in the 6-year-old ginseng roots compared with the 3-year-old ginseng roots, which indicates that HMGRs have constant and specific roles in the accumulation of ginsenosides in roots. Competitive inhibition of HMGR by mevinolin caused a significant reduction of total ginsenoside in ginseng adventitious roots. Moreover, continuous dark exposure for 2 to 3 d increased the total ginsenosides content in 3-year-old ginseng after the dark-induced activity of PgHMGR1. These results suggest that PgHMGR1 is associated with the dark-dependent promotion of ginsenoside biosynthesis. We also observed that the PgHMGR1 can complement Arabidopsis (Arabidopsis thaliana) hmgr1-1 and that the overexpression of PgHMGR1 enhanced the production of sterols and triterpenes in Arabidopsis and ginseng. Overall, this finding suggests that ginseng HMGRs play a regulatory role in triterpene ginsenoside biosynthesis. © 2014 American Society of Plant Biologists. All rights reserved.


Hong C.-E.,Chonnam National University | Park A.-K.,Sunchon National University | Lyu S.-Y.,Sunchon National University
Molecular and Cellular Biochemistry | Year: 2014

We studied the effects, either combined or alone, of lectin from Korean mistletoe (Viscum album var. coloratum agglutinin, VCA) and doxorubicin (DOX) in MCF-7 (estrogen receptor-positive) and MDA-MB231 (estrogen receptor-negative) human breast cancer cells. When VCA and DOX were combined, a strong synergistic effect was shown in cell growth inhibition, compared to VCA or DOX treatment alone. In quantitative apoptosis studies analyzed by flow cytometry, a combination of two agents showed an increase in apoptosis in both cells, compared to agents alone. Also, pro-apoptotic proteins including Bax, Bik, and Puma were increased in both cells, and the survival factor Bcl-2 was inhibited in MCF-7 cells when drugs were combined. Furthermore, VCA combined with DOX mediated S phase arrest, accompanied with a decrease of cell number at G0/G1 phase. This suggests that VCA and DOX combination may possibly lead to a novel strategy for the treatment of breast cancer. © 2014, Springer Science+Business Media New York.


Kwak Y.J.,Chonbuk National University | Park H.R.,Chonnam National University | Song M.Y.,Chonbuk National University
Metals and Materials International | Year: 2013

Magnesium with oxides or transition elements prepared by mechanical grinding under H2 (reactive mechanical grinding) showed relatively high hydriding and dehydriding rates when the content of additives was about 20 wt%. Ni, Fe2O3, and Fe were chosen as the oxides or transition elements to be added. Ti was also selected since it was considered to increase the hydriding and dehydriding rates by forming Ti hydride. Samples Mg-14Ni-3Fe2O3-3Ti (Sample A) and Mg-14Ni-2Fe 2O3-2Ti-2Fe (Sample B) were prepared by reactive mechanical grinding, and their hydrogen storage properties were compared. The activated Sample A had a little smaller hydriding rate than the activated Sample B, but a higher dehydriding rate than the activated Sample B. Sample A exhibits quite a larger dehydriding rate and quantity of hydrogen desorbed for 60 min than any other Mg-xNi-yFe2O3-zM (M=transition metals) samples. An addition of a relatively larger amount of Ti is considered to lead to quite a high hydriding rate and a high dehydriding rate of Sample A. © 2013 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.


Sexual health or erectile dysfunction (ED) state of the art guidelines provide a thorough overview of conventional prescription or other notable extrinsic treatment options. Yet, over the past 1015 years, a plethora of international researchers have established that individual and comprehensive lifestyle changes can prevent and potentially improve ED. We review the lifestyle evidence that should equate to grade A or level 1 evidence recommendations for ED. We also review the evidence for Panax ginseng, an over-the-counter (OTC) dietary supplement with a 35-year history of laboratory investigations, multiple positive randomized trials over approximately 15 years and several independent meta-analyses and systematic reviews. Perhaps it is time to at least discuss and even emphasize lifestyle and other non-conventional interventions in ED guidelines so that patients can explore a diversity of potentially synergistic choices with their physicians and can improve their quality and quantity of life. Ignoring the consistent, positive data on lifestyle modifications in ED guidelines, for example, is tantamount to ignoring diet and lifestyle changes to reduce the risk of or ameliorate cardiovascular diseases. © 2012 AJA, SIMM & SJTU. All rights reserved.


Kim C.S.,Chonnam National University
Electrolyte and Blood Pressure | Year: 2013

Cardio-renal syndromes are disorders of the heart and kidney wherein acute or long-term dysfunction in one organ may induce acute or long-term dysfunction of the other. Because of this complex organ interaction, management of cardiorenal syndrome must be tailored to the underlying pathophysiology. Clinical guidelines exist for the treatment of heart failure or renal failure as separate conditions. Thus far, however, there has been no consensus about managing patients with cardio-renal and reno-cardiac syndromes. Pharmacologic treatment remains a controversial subject. Standard cardiac drugs such as diuretics and inotropes may have limited effect because resistance often develops after long- term use. Recent studies of patients with acute cardio-renal syndromes have focused on newer therapies, including phosphodiesterase inhibitors, vasopressin antagonists, adenosine A1 receptor antagonists, and renal protective dopamine. Initial clinical trials of these agents have shown encouraging results in some patients with heart failure, but have failed to demonstrate a clear superiority over more conventional treatments. Similarly, the benefits of diuretics, aspirin, erythropoietin agents, and iron supplements for management of chronic cardiorenal syndromes are unknown. Copyright © 2013 The Korean Society of Electrolyte Metabolism.


Park S.-Y.,Chonnam National University
Molecular Therapy | Year: 2014

MicroRNAs are increasingly implicated in the modulation of the progression of various cancers. We previously observed that KAI1 C-terminal interacting tetraspanin (KITENIN) is highly expressed in sporadic human colorectal cancer (CRC) tissues and hence the functional KITENIN complex acts to promote progression of CRC. However, it remains unknown that microRNAs target KITENIN and whether KITENIN-targeting microRNAs modulate CRC cell motility and colorectal tumorigenesis. Here, through bioinformatic analyses and functional studies, we showed that miR-124, miR-27a, and miR-30b negatively regulate KITENIN expression and suppress the migration and invasion of several CRC cell lines via modulation of KITENIN expression. Through in vitro and in vivo induction of mature microRNAs using a tetracycline-inducible system, miR-124 was found to effectively inhibit the invasion of CT-26 colon adenocarcinoma cells and tumor growth in a syngeneic mouse xenograft model. Constitutive overexpression of precursor miR-124 in CT-26 cells suppressed in vivo tumorigenicity and resulted in decreased expression of KITENIN as well as that of MYH9 and SOX9, which are targets of miR-124. Thus, our findings identify that KITENIN-targeting miR-124, miR-27a, and miR-30b function as endogenous inhibitors of CRC cell motility and demonstrate that miR-124 among KITENIN-targeting microRNAs plays a suppressor role in colorectal tumorigenesis.Molecular Therapy (2014); doi:10.1038/mt.2014.105.


Lee B.-K.,Chonnam National University
Polymer Engineering and Science | Year: 2014

In this study, a microfluidic chip prototype having circular microchannels was replicated by microinjection molding process, employing a modularized and sectioned micromold system (MSMS). In the viewpoint of microfluidic manipulation, a microchannel with circular cross-section shows several advantages over a conventional rectangular and/or square microchannel. To achieve a mass production of the microchannels with circular or round cross-sections, the micromold was designed and fabricated based on the concept of MSMS. It consisted of several micromold modules, each having half-circular cross-sectional microstructures on its one-side surface. The modules were precisely manufactured by a deep X-ray lithography using a synchrotron radiation and a subsequent nickel electroforming process. Then, the MSMS for a microinjection molding process was constructed by assembling the nickel modules. After the molding of plastic plate with open microchannels of half-circular cross-section, a thermal bonding of microinjection-molded plates was carried out to produce the microfluidic chip prototype including the circular microchannels. Observation of the surface quality, measurement of cross-sectional profiles, and microfluidic test were carried out, which verified the usefulness of the present fabrication process. © 2013 Society of Plastics Engineers.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C21H26N2O4, triclinic, P1̄ (no. 2), a = 7.010(1) Å, b = 7.949(1) Å, c = 18.280(3) Å, α = 93.363(4)°, β = 91.696(4)°, γ = 98.099(4)°, V = 1006.0 Å3, Z = 2, Rgt(F) = 0.063, wR ref(F2) = 0.167, T = 200 K. © by Oldenbourg Wisscnschaftsvcrlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C12H8I2N2Pd, monoclinic, P121/c1 (no. 14), a = 10.3552(7) Å, b = 18.016(1) Å, c = 7.3535(5) Å, β = 108.659(2)°, V = 1299.8 Å3, Z = 4, Rgt(F) = 0.043, wRref(F2) = 0.093, T = 200 K. © by Oldenbourg Wissenschaftsverlag, M̈unchen.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C8H6I2N4Pt, monoclinic, C12/c1 (no. 15), a = 16.060(3) Å, b = 15.193(2) Å, c = 10.546(2) Å, β= 113.416(3)°, V = 2361.3 Å3, Z = 8, R gt(F) = 0.046, wRrefF2) = 0.119, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C14H24N2O9Pd, triclinic, P1̄ (no. 2), a = 6.9426(6) Å, b = 12.467(1) Å, c= 12.834(1) A, a = 115.053(2)°, β = 97.102(2)°, γ = 98.043(2)°, V = 975.5 Å3, Z = 2, Rgt(F) = 0.050, wR ref(F2) = 0.109, T= 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C12H8N4PdS2, orthorhombic, Pbcm (no. 57), a = 10.294(1) Å, b = 19.991(2) Å, c = 6.4727(8) Å, V = 1332.0 Å3, Z = 4, Rgt(F) = 0.051, wRref(F2) = 0.121, T = 200 K. © by Oldenbourg Wissenschaftsverlag, M̈unchen.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C26H18I2N2Pd, triclinic, P1̄ (no. 2), a = 8.9178(6) Å, b = 9.0367(7) Å, c = 9.2046(7) Å, a = 114.320(1)°, β= 114.577(1)°,γ = 96.967(1)°, V= 575.2 Å3,Z = 1, Rgl(F) = 0.023, wR ref(F2) = 0.064, T = 200 K. © by Oldenbourg Wisscnschaftsverlag, Miinchen.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2010

C12H16Cl2MnN4O4, monoclinic, P121/c1 (no. 14), a = 14.6283(7) Å, b = 13.9519(6) Å, c = 8.7216(4) Å, β= 101.565(1)°, V = 1743.9 Å3 Z = 4, Rgt(F) = 0.039, wRref(F 2) = 0.108, T = 200 K. © by Oldenbourg Wissenschaftsverlag, München.


Kim J.W.,Chonnam National University
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians | Year: 2013

The aim of this study was to evaluate the effect of inflatable obstetric belts on uterine fundal pressure in the management of the second stage of labor. Between July 2009 and December 2010, 188 nulliparous women with a singleton pregnancy at term were enrolled and only one dropped. The participants were randomized to receive either standard care (control group, n = 91) or uterine fundal pressure by the Labor Assister (Baidy M-520/Curexo, Inc., Seoul, Korea; active group, n = 97) during the second stage of labor in addition to standard care. The Labor Assister is an inflatable obstetric belt that is synchronized to apply constant fundal pressure during a uterine contraction. The primary endpoint was duration of the second stage of labor in women who delivered vaginally (control, n = 80 versus active, n = 93). It was not analyzed in women who delivered by cesarean section (n = 14) and delivered precipitously (n = 1). The secondary outcomes are perinatal outcomes and perineal laceration. Participants received patient-controlled epidural analgesia. The 93 women in the active group spent less time in the second stage of labor when compared to the 80 women in the control group (46.51 ± 28.01 min versus 75.02 ± 37.48 min, p < 0.001). There was no significant difference in perinatal outcomes and perineal laceration between the two groups. The uterine fundal pressure exerted by the inflatable obstetric belt reduces the duration of the second stage of labor without complications in nulliparous women who receive patient-controlled epidural analgesia.


Jung Y.H.,Chonnam National University
The American journal of emergency medicine | Year: 2013

Catheter-related right atrial thrombus (RAT) is an uncommon life-threatening complication. Few cases of endovascular cooling catheter-related complications have been reported. We report the first case of endovascular cooling catheter-related RAT. A 17-year-old adolescent boy was treated with therapeutic hypothermia using an endovascular cooling catheter following ventricular fibrillation cardiac arrest. He became alert, but RAT was found 3 days after the placement of the cooling catheter. Anticoagulation with enoxaparin for 2 weeks completely resolved the RAT, and he was consequently treated with radiofrequency ablation and received an implanted cardiac defibrillator. This case report highlights the occurrence of endovascular cooling catheter-related RAT early after the placement of a catheter. Physicians should monitor whether RAT occurs during and following therapeutic hypothermia with a cooling catheter.


Han J.-B.,Seoul National University | Hong S.-Y.,Seoul National University | Song J.-H.,Chonnam National University
Journal of Sound and Vibration | Year: 2012

Energy Flow Analysis (EFA) has been developed to predict the vibration energy density of system structures in the high frequency range. This paper develops the energy flow model for the thin plate in contact with mean flow. The pressure generated by mean flow affects energy governing equation and power reflectiontransmission coefficients between plates. The fluid pressure is evaluated by using velocity potential and Bernoulli's equation, and energy governing equations are derived by considering the flexural wavenumbers of a plate, which are different along the direction of flexural wave and mean flow. The derived energy governing equation is composed of two kinds of group velocities. To verify the developed energy flow model, various numerical analyses are performed for a simple plate and a coupled plate for several excitation frequencies. The EFA results are compared with the analytical solutions, and correlations between the EFA results and the analytical solutions are verified. © 2012 Elsevier Ltd. All rights reserved.


Je J.-Y.,Chonnam National University | Kim S.-K.,Pukyong National University
Advances in Food and Nutrition Research | Year: 2012

Chitosan, the most abundant marine mucopolysaccharide, is derived from chitin by alkaline deacetylation, and possesses versatile biological properties such as biocompatibility, biodegradability, and a non-toxic nature. Due to these characteristics, considerable attention has been given to its industrial applications in the food, pharmaceutical, agricultural, and environmental industries. Currently, chitosan can be considered as a potential marine nutraceutical because its remarkable biological activities have been investigated and reported, in order to exploit its nutraceutical properties. This chapter, therefore, reviews the biological activities of chitosan including antioxidant, hypocholesterolemic, antimicrobial, and anti-inflammatory activities, as well as its mode of action in each activity. © 2012 Elsevier Inc.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

In the title complex, [MnCl2(C18H12N 6)], the MnII ion is five-coordinated in an approximately square-pyramidal geometry defined by three N atoms of the tridentate 2,4,6-tri-2-pyridyl-1,3,5-triazine ligand and two Cl atoms. In the crystal, the mol-ecules are stacked in columns along the c axis and display inter-molecular π-π inter-actions between the six-membered rings, the shortest centroid-centroid distance being 3.553 (3)Å. Inter-molecular C - H⋯Cl contacts are also noted.


Yeh S.-W.,Hanyang University | Ham Y.-G.,Chonnam National University | Kirtman B.P.,University of Miami
Geophysical Research Letters | Year: 2014

This study examines changes in the structure of El Niño-Southern Oscillation (ENSO) amplitude using the historical climate simulations of the World Climate Research Program Coupled Model Intercomparison Project (CMIP) phase-3 and phase-5 coupled general circulation models (CGCMs). The analysis focuses on the "so-called" Bjerknes feedback. The Bjerknes feedback affects the sea surface temperature (SST) variability differently between the CMIP3 and CMIP5 models. In the CMIP5 models, the strength of the Bjerknes feedback is associated with the amplitude of ENSO, whereas the changes in the strength of Bjerknes feedback are not associated with changes in ENSO amplitude in CMIP3 CGCMs. The relationship between the Bjerknes feedback and the SST anomaly variance is suggested as a possible explanation for the eastward shift in the SST anomaly variance in CMIP5 relative to CMIP3. Key Points Understanding of ENSO amplitude changes Understanding of Bjerknes feedback in model Identifying the difference in CMIP3 and CMIP5 ©2013. American Geophysical Union. All Rights Reserved.


Ham Y.-G.,Chonnam National University | Kug J.-S.,Pohang University of Science and Technology
Geophysical Research Letters | Year: 2016

This study examines the relationship between the intermodel diversities of the present climate climatology and those of El Niño-Southern Oscillation (ENSO) amplitude change under global warming in the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. The models with increased ENSO amplitude under greenhouse warming (i.e., "ENSO-amplified models") tend to simulate a twentieth century stronger climatological Intertropical Convergence Zone and South Pacific Convergence Zone over the central-eastern Pacific that are located farther away from the equator during boreal spring. Moisture budget analysis indicates that those climatological differences lead to stronger positive climatological precipitation change over the off-equatorial central-eastern Pacific under greenhouse warming. The stronger positive climatological precipitation change enhances the air-sea coupling strength over the central-eastern Pacific, which leads to increase the ENSO amplitude. ©2015. American Geophysical Union.


Lee G.-Y.,Korea Advanced Institute of Science and Technology | Im W.B.,Chonnam National University | Kirakosyan A.,Korea Advanced Institute of Science and Technology | Cheong S.H.,Korea Advanced Institute of Science and Technology | And 2 more authors.
Optics Express | Year: 2013

A series of single-phased emission-tunable Na0.34Ca 0.66Al1.66Si2.34O8:Eu 2+,Mn2+ phosphors were successfully synthesized by a wet-chemical synthesis method. Photoluminescence excitation (PLE) spectra indicate that the phosphor can be efficiently excited by UV radiation from 250 to 420 nm. Also, NCASO:Eu2+,Mn2+ phosphor exhibit a broad blue emission band at 440 nm and an orange emission band at 570 nm, which originate from Eu2+ and Mn2+ ions, respectively. Therefore, overall emission color can be tuned from blue to white by increasing the concentration of Mn2+ ions in the host lattice utilizing energy transfer from Eu2+ to Mn2+ ions. This energy transfer phenomenon was demonstrated to be a resonant type through dipole-dipole interaction determined with the help of PL spectra, decay time measurement, and energy transfer efficiency of the phosphor. These results indicate that NCASO:Eu2+,Mn2+ can be a promising single-phased whiteemitting phosphor for white-light UV LEDs. © 2013 Optical Society of America.


Park S.E.,Korea Research Institute of Standards and Science | Noh H.-R.,Chonnam National University
Optics Express | Year: 2013

We report the polarization dependence of the spectrum in modulation transfer spectroscopy for the transitions from the lower ground state (F g = 1) of 87Rb atoms. We measured the spectra for the two polarization configurations where the carrier and probe beams were linearly polarized in parallel or perpendicular directions. The measured spectra were in excellent agreement with calculated results. The spectra were strongly dependent on the polarization configurations. In particular, the signal for parallel polarization configuration was generated via an incoherent process mediated by spontaneous emission. © 2013 Optical Society of America.


Song M.Y.,Chonbuk National University | Kwon S.N.,Chonbuk National University | Park H.R.,Chonnam National University
Journal of Korean Institute of Metals and Materials | Year: 2013

In this work, Mg-x wt% Fe2O3 wt% Ni alloys were prepared by mechanical grinding under hydrogen (reactive mechanical grinding) using a planetary ball mill, and pressure-composition isotherms of the samples were subsequently obtained. By measuring the absorbed hydrogen quantity as a function of number of cycles, the cycling properties of a Mg-5 wt% Fe 2O3-15 wt% Ni alloy was investigated. The Mg-10 wt% Fe2O3-5 wt% Ni alloy showed an equilibrium plateau pressure of 1.92 bar at 593 K and had a hydrogen storage capacity of 5.47 wt% at 593 K. The absorbed hydrogen quantity decreased as the number of cycles increased. The Ha value varied almost linearly with the number of cycles. The maintainability of absorbed hydrogen quantity at n = 150 was 73.8% for the hydriding reaction time of 60 min. Copyright © The Korean Institute of Metals and Materials.


Song M.Y.,Chonbuk National University | Kwak Y.J.,Chonbuk National University | Lee S.H.,Chonbuk National University | Park H.R.,Chonnam National University
Journal of Korean Institute of Metals and Materials | Year: 2013

In order to investigate the formation of a high pressure form of magnesium hydride, Y-MgH2, X-ray diffraction patterns before and after the hydriding reaction were obtained for samples of MgH2, MgH 2after reactive mechanical grinding (RMG), and 94 wt% MgH 2-6 wt% Ni after reactive mechanical grinding. In addition, absorbed hydrogen quantity versus time curves at the first cycle were examined. The MgH2 sample did not contain Y-MgH2. However, the MgH 2 after RMG and the 94 wt% MgH2-6 wt% Ni after RMG contained Y-MgH2. All these results prove that after reactive mechanical grinding, y-MgH2, one of the high pressure forms of MgH2, was formed in the MgH2 and 94 wt% MgH2-6 wt% Ni samples under low hydrogen pressures. © The Korean Institute of Metals and Materials.


Kim H.-J.,Seoul National University | Lee S.-H.,Chonnam National University | Park J.H.,Seoul National University | Choi J.-Y.,Korea University | Kim J.-S.,Seoul National University
Journal of Neurology | Year: 2014

Cerebral infarction presenting with isolated vertigo remains a diagnostic challenge. To define the clinical characteristics of unilateral infarctions restricted to the vestibular nuclei, two patients with isolated unilateral vestibular nuclear infarction had bedside and laboratory evaluation of the ocular motor and vestibular function, including video-oculography, bithermal caloric irrigation, the head impulse test (HIT) using magnetic scleral coils, and cervical and ocular vestibular-evoked myogenic potentials (VEMPs). We also reviewed the literature on isolated vertigo from lesions restricted to the vestibular nuclei, and analyzed the clinical features of seven additional patients. Both patients showed spontaneous torsional-horizontal nystagmus that beat away from the lesion side, and direction-changing gaze-evoked nystagmus. Recording of HIT using a magnetic search coil system documented decreased gains of the vestibular-ocular reflex for the horizontal and posterior semicircular canals on both sides, but more for the ipsilesional canals. Bithermal caloric tests showed ipsilesional canal paresis in both patients. Cervical and ocular VEMPs showed decreased or absent responses during stimulation of the ipsilesional ear. Initial MRIs including diffusion-weighted images were normal or equivocal, but follow-up imaging disclosed a circumscribed acute infarction in the area of the vestibular nuclei. Infarctions restricted to the vestibular nuclei may present with isolated vertigo with features of both peripheral and central vestibulopathies. Central signs should be sought even in patients with spontaneous horizontal-torsional nystagmus and positive HIT. In patients with combined peripheral and central vestibulopathy, a vestibular nuclear lesion should be considered especially when hearing is preserved. © 2013 Springer-Verlag Berlin Heidelberg.


Kim J.-H.,Gwangju Institute of Science and Technology | Jeon J.,Gwangju Institute of Science and Technology | Shin M.,Gwangju Institute of Science and Technology | Won Y.,Gwangju Institute of Science and Technology | And 7 more authors.
Cell | Year: 2014

Osteoarthritis (OA), primarily characterized by cartilage degeneration, is caused by an imbalance between anabolic and catabolic factors. Here, we investigated the role of zinc (Zn2+) homeostasis, Zn2+ transporters, and Zn2+-dependent transcription factors in OA pathogenesis. Among Zn2+ transporters, the Zn2+ importer ZIP8 was specifically upregulated in OA cartilage of humans and mice, resulting in increased levels of intracellular Zn2+ in chondrocytes. ZIP8-mediated Zn2+ influx upregulated the expression of matrix-degrading enzymes (MMP3, MMP9, MMP12, MMP13, and ADAMTS5) in chondrocytes. Ectopic expression of ZIP8 in mouse cartilage tissue caused OA cartilage destruction, whereas Zip8 knockout suppressed surgically induced OA pathogenesis, with concomitant modulation of Zn2+ influx and matrix-degrading enzymes. Furthermore, MTF1 was identified as an essential transcription factor in mediating Zn2+/ZIP8-induced catabolic factor expression, and genetic modulation of Mtf1 in mice altered OA pathogenesis. We propose that the zinc-ZIP8-MTF1 axis is an essential catabolic regulator of OA pathogenesis. © 2014 Elsevier Inc.


Noh H.-R.,Chonnam National University
Journal of the Optical Society of America B: Optical Physics | Year: 2016

We present an analytical study of susceptibility in pump-probe laser spectroscopy for an atomic medium composed of two-level atoms in the Doppler-broadened limit. We derive an accurate analytical formula for susceptibility up to the first (arbitrary) order at the Rabi frequency of the probe (pump) beam. This is expressed in a succinct single term rather than as a complicated summation, as presented in previous papers. We also derive analytical solutions for the linewidth and peak value of the absorption spectrum of the probe beam. © 2016 Optical Society of America.


Bang Y.,Chonnam National University | Stewart G.R.,University of Florida
New Journal of Physics | Year: 2016

The strong power lawbehavior of the specific heat jump ΔC versus Tc (ΔC Tc ∼ Tc α, α ≈ 2), first observed by Budko et al (2009 Phys. Rev. B 79 220516), has been confirmed with several families of the Fe-based superconducting compounds with various dopings.Wehave tested a minimal two band BCS model to understand this anomalous behavior and showed that this non-BCS relation between ΔC versus Tc is a generic property of the multiband superconducting state paired by a dominant interband interaction (Vinter > Vintra) reflecting the relation Δh/Δe ∼ √Ne/Nh near Tc, as in the S?-wave pairing state. We also found that this ΔC versus Tc power lawcan continuously change fromthe ideal BNCscaling to a considerable deviation by amoderate variation of the impurity scattering rate G0 (non-pairbreaking). As a result, our model provides a consistent explanation why the electron-doped Fe-based superconductors follow the idealBNCscaling very well while the hole-doped systems often show varying degree of deviations. © 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.


Senthilkumar S.T.,Bharathiar University | Selvan R.K.,Bharathiar University | Ponpandian N.,Bharathiar University | Melo J.S.,Bhabha Atomic Research Center | Lee Y.S.,Chonnam National University
Journal of Materials Chemistry A | Year: 2013

Electric double layer capacitors (EDLCs) were fabricated using biomass derived porous activated carbon as electrode material with 1 M H 2SO4 and VOSO4 added 1 M H2SO 4 as electrolytes. Here, VOSO4 was used as redox additive to improve the overall performance of EDLC. As expected, the VOSO4 electrolyte showed ∼43% of improved specific capacitance of 630.6 F g -1 at 1 mA cm-2 compared to pristine 1 M H 2SO4 (440.6 F g-1) due to the contribution of VO2+/VO2 + redox reaction at the electrode-electrolyte interface. Possible redox reaction mechanism of VO 2+/VO2 + pair is also briefly illustrated. The good cycling performance of 97.57% capacitance retention was observed even after 4000 cycles. For comparison, the polymer gel electrolyte (PVA/VOSO 4/H2SO4) was also prepared and then the performance of the fabricated EDLCs was studied. Overall, these findings could open up a simple and cost effective way to improve the performance of EDLCs significantly. © 2013 The Royal Society of Chemistry.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2013

(Equation presentation) (Table presentation) Source of material To a solution of K2PtCl4 (0.205 g, 0.493 mmol) in H2O (40 ml) were added KSCN (0.505 g, 5.194 mmol) and 3-phenylpyridine (ppy; 0.174 g, 1.121mmol) in EtOH (10 ml) and stirred for 24 h at room temperature. The formed precipitate was separated by filtration, washed with H2O and EtOH, and dried at 50 °C, to give a pale yellow powder (0.244 g). Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from a CH3CN solution. Experimental details Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms with d(C-H) = 0.95 Å and Uiso(H) = 1.2Ueq(C). The highest peak (1.16 e.Å-3) and the deepest hole (-0.90 e.Å-3) in the difference Fourier map are located 0.89Åand 0.89 Å from the atom Pt1, respectively. Discussion Crystal structures of the related Pd(II) complex [PdCl2(ppy)2] and Pt(IV) anionic complex (H-ppy)[PtCl5(ppy)].H2O have been reported previously [1, 2]. The central Pt(II) ion in the title complex [Pt(SCN)2(ppy)2] has a trans-S2N2 square-planar coordination defined by two N atoms from two 3-phenylpyridine ligands and two S atoms of two SCN- anions. The Pt atom is located on an inversion center, and therefore the asymmetric unit contains one half of the complex and the PtS2N2 moiety is exactly planar. The pyridine ring of the ligand is almost perpendicular to the PtS2N2 plane (86.4(1)°). In the crystal structure, the ppy ligand is not planar. The pyridine and phenyl rings are twisted by 20.7(2)°. The thiocyanato ligand is almost linear with a S-C-N bond angle of 179.0(5)°, and the S atoms are coordinated to the Pt atom with the nearly tetrahedral Pt-S-C bond angle of 105.4(2)°, characteristic of an S-bonded conformation [3, 4]. The complex molecules are stacked in columns along [010] with d(Pt...Pt) = 5.3464(8) Å (= length of b axis) and successive complexes stack in opposite directions along [001]. In the columns, several intermolecular π-π interactions between the aromatic rings are present. The shortest distance between Cg1 (the centroid of ring N1-C5) and Cg2i (the centroid of ring C6-C11, symmetry code i: x, y-1, z) is 3.777(3) Å, and the dihedral angle between the ring planes is 20.7(2)°. Moreover, the complex displays intermolecular C-H...N hydrogen bonds with d(C...N) = 3.395(7) Å and 3.402(7) Å. (Table presentation).


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2013

(Equation presentation) (Table presentation) Source of material To a solution of K2PtCl4 (0.210 g, 0.506 mmol) in H2O (20 ml) was added 3-phenylpyridine (ppy; 0.159 g, 1.026mmol) in EtOH (10 ml) and stirred for 20 h at room temperature. The formed precipitate was separated by filtration, washed with H2O and EtOH, and dried at 50 °C, to give a pale yellow powder (0.247 g). Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from an N,N-dimethylformamide solution at 60 °C. Experimental details Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms with d(C-H) = 0.95 Å and Uiso(H) = 1.2Ueq(C). The highest peak (1.02 e.Å-3) and the deepest hole (-0.46 e.Å-3) in the difference Fourier map are located 1.05Åand 0.81 Å from the atoms H7 and Pt1, respectively. Discussion This contribution is part ofmycontinuing interest in the structural chemistry of platinum complexes [1, 2]. In the title complex [PtCl2(ppy)2], the central Pt(II) ion has a trans-Cl2N2 square-planar coordination defined by two N atoms from two distinct 3- phenylpyridine ligands and two chlorido ligands. The complex crystallizes in themonoclinic space group P21/c,whereas the previously reported analogous Pd(II) complex [PdCl2(ppy)2] crystallizes in the triclinic space group P1 [3]. Crystal structure of the related ppy-Pt(IV) anionic complex, (H-ppy)[PtCl5(ppy)].H2O, has been investigated previously [4]. The asymmetric unit of the title crystal structure contains one half of the title complex with the Pt atom located on an inversion center. Therefore the PtCl2N2 moiety is exactly planar. The dihedral angle between the PtCl2N2 unit plane and the nearly planar pyridine ring is 60.59(9)°. In the crystal, the pyridine and phenyl rings of each ligand are twisted by 39.3(1)°. The complexes are stacked in columns along [100] with d(Pt...Pt) = 9.6278(15) Å (= length of a axis). Along [010], successive complexes stack in opposite directions. In the columns, several intermolecular π-π interactions between adjacent sixmembered rings are present. For Cg1 (the centroid of ring N1-C5) and Cg1i (symmetry code i: 1-x,-y,1-z), the centroid-centroid distance is 3.819(2) Å, the planes are parallel and shifted by 1.663 Å. (Table presentation).


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2013

(Equation presentation) (Table presentation) Source of material To a solution ofK2PtBr4 (0.296 g, 0.50mmol) inH2O(20 ml) and EtOH (20 ml) was added 4-phenylpyridine (ppy; 0.159 g, 1.03 mmol) and stirred for 3 h at roomtemperature. The formed precipitate was separated by filtration, washed with H2O and EtOH, and dried at 50 °C, to give a yellow powder (0.301 g). Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from an N,N-dimethylformamide (DMF) solution at 60 °C. Experimental details Hydrogen atoms were positioned geometrically and allowed to ride on their respective parent atoms with d(C-H) = 0.95 Å and Uiso(H) = 1.2Ueq(C). One pyridine ring (N1-C3) and one benzene ring (C11-C14) displayed relatively large anisotropic displacement parameters so that the rings appear to be partially disordered. The C1, C2, C12 and C13 atoms were refined anisotropically as disordered over two sites using EADP option of the SHELX program [2]. The site occupancy factors are 0.547(18) for the C1A and C2A atoms, and 0.528(11) for the C12A and C13A atoms, respectively. The highest peak (0.49 e.Å-3) and the deepest hole (-0.85 e.Å-3) in the difference Fourier map are located 0.56Åand 0.78Åfrom the atomsN2 and Pt1, respectively. Discussion The title complex [PtBr2(ppy)2] is isomorphous with the previously reported chlorido-Pd(II) complex [PdCl2(ppy)2] [1]. The asymmetric unit of the title crystal structure contains one half of a neutral Pt(II) complex. The complex is disposed about a twofold rotation axis running in the [010] direction passing through the Pt1, N1, C3, C4, C7, N2, C10, C11 and C14 atoms. The central Pt(II) ion has a trans-Br2N2 square-planar coordination geometry defined by two N atoms from two 4-phenylpyridine ligands and two bromido ligands. The two Pt-N bond lengths are nearly equal with d(Pt-N) = 2.017(4) and 2.024(4) Å, and the N-Pt-Br bonds are almost perpendicular. In the refinement, the pyridine ring N1- C3 and the benzene ring C11-C14 were found to be disordered over two sites with the site-occupancy factors of 0.547(18) and 0.528(11), respectively, for the major components. The dihedral angles between the major and minor rings are 27(1)° for the ring N1-C3 and 34.7(9)° for the ring C11-C14, respectively. (Table presentation).


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2013

(Equation presentation) (Table presentation) Source of material To a solution of K2PtCl4 (0.204 g, 0.49 mmol) and KI (0.717 g, 4.32 mmol) in H2O (20 ml) was added 3-phenyl- pyridine (ppy; 0.173 g, 1.12 mmol) in EtOH (10 ml) and stirred for 3 h at room temperature. The formed precipitate was separated by filtration, washed with H2O and EtOH, and dried at 50 °C, to give a yellow powder (0.343 g). Crystals suitable for X-ray diffraction were obtained by slow evaporation from an N,N-dimethylformamide solution at 60 °C. Experimental details Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms with d(C-H) = 0.95 Å and Uiso(H) = 1.2Ueq(C). The highest peak (0.76 e.Å-3) and the deepest hole (-1.01 e.Å-3) in the difference Fourier map are located 0.83Åand 1.01 Å from the Pt1 atom, respectively. Discussion The title complex is isomorphous with the previously reported bromido-Pt(II) complex [PtBr2(ppy)2] [1]. The central Pt(II) ion has a trans-I2N2 square-planar coordination geometry defined by two N atoms from two ppy ligands and two iodido ligands. The Pt atom is located on an inversion center, and thus the asymmetric unit contains one half of the complex and the PtI2N2moiety is exactly planar. The dihedral angle between the PtI2N2 moiety and the nearly planar pyridine ring is 71.8(2)°. In the crystal structure, the dihedral angle between the pyridine and benzene ring planes is 33.0(2)°. The complexes are stacked in columns along [010] with d(Pt...Pt) = 7.154(1) Å (= length of b axis). In the columns, several intermolecular π-π interactions between adjacent sixmembered rings are present. For Cg1 (the centroid of ring C6- C11) and Cg1i (symmetry code i: 1-x,1-y,1-z), the centroid-centroid distance is 4.137(4) Å, the planes are parallel and shifted by 1.928 Å. (Table presentation).


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2013

(Equation presentation) (Table presentation) Source of material To a solution of Na2PdCl4 (0.297 g, 1.01 mmol) in H2O (30 ml) and MeOH (30 ml) was added 2,2'-bipyrimidine (bpym, 0.16 g, 1.01mmol). The mixture was stirred for 3 h at room temperature. The precipitate was separated by filtration, washed with H2Oand MeOH, and dried at 50 °C, to give a yellow powder (0.3033 g). Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from an N,N-dimethylformamide solution at 60 °C. Experimental details Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms with d(C-H) = 0.95 Å and Uiso(H) = 1.2Ueq(C). The highest peak (0.41 e.Å-3) and the deepest hole (-1.00 e.Å-3) in the difference Fourier map are located 1.10Åand 1.07 Å from the atom Pd1, respectively. Discussion The title complex [PdCl2(bpym)] crystallized in the monoclinic space group P21/c like the analogous Pt complexes [PtCl2(bpym)] [1] and [PtBr2(bpym)] [2], and the asymmetric unit contains a complexmolecule. The central Pd(II) ion is four-coordinated in a slightly distorted square-planar environment defined by two pyrimidine N atoms derived from a chelating bpym ligand and two mutually cis chloride anions. The main contribution to the distortion is the tight N1-Pd1-N4 chelate bite angle of 80.45(8)°, which results in non-linear trans axes (πN1-Pd1-Cl1 = 174.71(6)° and πN4-Pd1-Cl2 = 174.40(6)°). The Pd-N and Pd-Cl bond lengths are almost equivalent, respectively (d(Pd1-N1/N4) = 2.022(2) Å and 2.030(2) Å; d(Pd1-Cl1/Cl2 = 2.2827(7) Å and 2.2879(7) Å). The nearly planar bpym ligand [maximum deviation = 0.079(2) Å] is slightly inclined to the least-squares plane of the PdCl2N2 unit [maximum deviation = 0.043(1) Å], making a dihedral angle of 6.0(1)°. The molecules are stacked in columns along [100] and display numerous intermolecular π-π interactions between the adjacent pyrimidine rings. For Cg1 (the centroid of ring N1-C4) and Cg1i (symmetry code i: 1-x,1-y,-z), the centroid-centroid distance is 3.951(2) Å, the planes are parallel and shifted by 2.159 Å. (Table presentation).


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2013

(Equation presentation) (Table presentation) Source of material To a solution of K2PtCl4 (0.208 g, 0.50 mmol) and KI (0.729 g, 4.39 mmol) in H2O (20 ml) was added 2-phenylpyridine (ppy; 0.178 g, 1.15 mmol) in acetone (20 ml) and refluxed for 5 h. The formed precipitate was separated by filtration, washed with H2O and MeOH, and dried at 50 °C, to give a yellow powder (0.285 g). Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from a CH3CN solution. Experimental details Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms with d(C-H) = 0.95 Å (aromatic) or 0.98 Å (CH3) and Uiso(H) = 1.2Ueq(Carene) or 1.5Ueq(Cmethyl). The highest peak (1.55 e.Å-3) and the deepest hole (-1.20 e.Å-3) in the difference Fourier map are located 1.92 Å and 1.82 Å from the atom H13A, respectively. Discussion Single crystals of the title complex [PtI(C11H8N)(CH3CN)] were unexpectedly obtained during crystallization from a CH3CN solution of the reaction product prepared by the reaction ofK2PtCl4, KI and ppy. Crystal structure of the related chlorido-Pt(II) complex [PtCl(C11H8N)(ppy)] has been investigated previously [1]. In the title structure, the central Pt(II) ion is fourfold coordinated by oneNatom and oneCatom from the anionic (2-(pyridin-2-yl)- phenyl ligand, one N atom of CH3CN molecule and one iodido ligand in a distorted square-planar coordination geometry with the N atoms trans to each other. The main contribution to the distortion is made by the tight chelate angle of


Lee S.W.,Harvard University | Heo J.,Chonnam National University | Gordon R.G.,Harvard University
Nanoscale | Year: 2013

Recently, 2-dimensional electron gas (2-DEG) was discovered at the interface of Al2O3/SrTiO3 (STO) heterostructures, in which the amorphous Al2O3 layers were grown by atomic layer deposition (ALD). The saturated electron density at the Al2O3/STO heterostructures above the critical thickness of Al2O3 is explained by an oxygen diffusion mechanism. © The Royal Society of Chemistry 2013.


Han J.-H.,LG Innotek | Lim Y.-C.,Chonnam National University
Energies | Year: 2015

In this study, to achieve the constant current drive and brightness control without a separate pulse width modulation (PWM) converter, a single converter is designed and verified by experiment under the condition of a multiple LED light load with different output voltage (Vf) characteristics. In the case of the input of 140 Watt class level, the proposed converter can drive two voltage type 95 Vdc (300 mA) light emitting diode (LED) lights loads and 120 Vdc (300 mA) LED lights loads simultaneously. In addition, to improve commercial compatibility, the proposed converter is operated in a wide range of the input voltage 90~264 Vac; also, the Power Factor Correction (PFC) circuit with the input power factor of more than 0.9 is added. In order to maximize the power conversion efficiency, a LLC resonant converter is applied to the PFC block with the output voltage of 380 Vdc and to a DC-DC conversion block. Finally, reliability of the proposed converter is verified through total harmonic distortion (THD) and electromagnetic interference (EMI) tests. © 2015 by the authors.


Kim Y.B.,Chonnam National University | Kang S.J.,Korea Polytechnic University
International Journal of Hydrogen Energy | Year: 2010

Transient behavior is a key property in the vehicular application of proton exchange membrane (PEM) fuel cells. A better control technology is constructed to increase the transient performance of PEM fuel cells. A steady-state isothermal analytical fuel cell model is constructed to analyze mass transfer and water transport in the membrane. To prevent the starvation of air in the PEM fuel cell, time delay control is used to regulate the optimum stoichiometric amount of oxygen, although dynamic fluctuations exist in the PEM fuel cell power. A bidirectional DC/DC converter connects the battery to the DC link to manage the power distribution between the fuel cell and the battery. Dynamic evolution control (DEC) allows for adequate pulse-width modulation (PWM) control of the bidirectional DC/DC converter with fast response. Matlab/Simulink/ Simpower simulation is performed to validate the proposed methodology, increase the transient performance of the PEM fuel cell system and satisfy the requirement of energy management. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.


Kim Y.-B.,Chonnam National University
Journal of Power Sources | Year: 2010

Transient behaviour is a key parameter for the vehicular application of proton-exchange membrane (PEM) fuel cell. The goal of this presentation is to construct better control technology to increase the dynamic performance of a PEM fuel cell. The PEM fuel cell model comprises a compressor, an injection pump, a humidifier, a cooler, inlet and outlet manifolds, and a membrane-electrode assembly. The model includes the dynamic states of current, voltage, relative humidity, stoichiometry of air and hydrogen, cathode and anode pressures, cathode and anode mass flow rates, and power. Anode recirculation is also included with the injection pump, as well as anode purging, for preventing anode flooding. A steady-state, isothermal analytical fuel cell model is constructed to analyze the mass transfer and water transportation in the membrane. In order to prevent the starvation of air and flooding in a PEM fuel cell, time delay control is suggested to regulate the optimum stoichiometry of oxygen and hydrogen, even when there are dynamical fluctuations of the required PEM fuel cell power. To prove the dynamical performance improvement of the present method, feed-forward control and Linear Quadratic Gaussian (LQG) control with a state estimator are compared. Matlab/Simulink simulation is performed to validate the proposed methodology to increase the dynamic performance of a PEM fuel cell system. © 2010 Elsevier B.V. All rights reserved.


Chandrasekaran G.,Chosun University | Kim G.-J.,Chonnam National University | Shin H.-J.,Chosun University
Food Chemistry | Year: 2011

In this study, we found that the fruiting body of the medicinal and edible mushroom Sparassis crispa produces an alkaliphilic esterase. The substrate specificity of this esterase was high for a p-nitrophenyl acetate substrate. The S. crispa esterase was purified using ammonium sulphate precipitation, anion exchange and gel filtration chromatography. The recovery and purification yields of the enzyme were 15-17% and 70-73 folds from six different strains of S. crispa, respectively. The molecular weight of the purified enzyme was approximately 60 kDa, as determined by SDS-PAGE. A zymogram analysis using a tributyrin substrate revealed that this enzyme is an esterase. The optimum pH and temperature were 8.0 and 50°C, respectively. The pH and temperature stability profiles show that this enzyme is more stable under alkaline conditions and at 30-40°C. Km and Vmax for this esterase enzyme acting on p-nitrophenyl acetate were 0.2 mM and 0.5. U/mg proteins, respectively. © 2010 Elsevier Ltd.


Noh H.-R.,Chonnam National University
Optik | Year: 2015

We present analytical solutions of the populations of an alkali-metal atom in the presence of a weak linearly-polarized laser beam. After a general method for calculating rate equations is described, the analytical solutions of the populations for the transition F g =1→ F e =0, 1, 2 are obtained. Provided that the laser intensity is weak, the time-dependent analytical populations are exact. As examples, explicit results for the D2 and D1 transitions of an alkali-metal atom with a nuclear-spin angular momentum of I =3/2, such as 87Rb, 23Na, 7Li, or 39K, are presented. © 2015 Elsevier GmbH.


Senthilkumar S.T.,Bharathiar University | Selvan R.K.,Bharathiar University | Lee Y.S.,Chonnam National University | Melo J.S.,Bhabha Atomic Research Center
Journal of Materials Chemistry A | Year: 2013

Halogen (iodide, I-) added aqueous electrolyte facilitates the capacitive behaviour of biomass derived activated carbon based electric double layer capacitors. To produce economically viable electrodes in large scale for supercapacitors (SCs), the activated carbons (ACs) prepared from Eichhornia crassipes (common water hyacinth) by ZnCl2 activation. The prepared ACs were characterized by XRD, Raman, FT-IR and surface area, pore size and pore volume analysis. The electrochemical properties of the SCs were studied using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling stability. The 3I-/I 3 -, 2I-/ I2, 2I3 -/3I2 and I2/IO3 - pairs produce redox peaks in CV and a large Faradaic plateau in charge-discharge curves. Similarly, I- ions improves the good ionic conductivity (lower charge transfer resistance) at the electrode/electrolyte interface which was identified through EIS studies. The calculated specific capacitance and energy density was 472 F g-1 and 9.5 W h kg-1 in aqueous solution of 1 M H2SO4. Interestingly, nearly two-fold improved specific capacitance and energy density of 912 F g-1 and 19.04 W h kg-1 were achieved when 0.08 M KI was added in 1 M H 2SO4 electrolyte with excellent cycle stability over 4000 cycles. Subsequently, this improved specific capacitance and energy density was compared with 0.08 M KBr added to 1 M H2SO4 (572 F g -1, 11.6 W h kg-1) and 0.08 M KI added to 1 M Na 2SO4 (604 F g-1, 12.3 W h kg-1) as electrolytes. © The Royal Society of Chemistry 2013.


Guo X.W.,CAS Institute of Physics | Guo X.W.,Tohoku University | Fang X.P.,CAS Institute of Physics | Sun Y.,CAS Institute of Physics | And 4 more authors.
Journal of Power Sources | Year: 2013

SnO2 attracts considerable interest as a promising high-capacity anode material for lithium ion batteries. It is believed that SnO2 stores lithium by the alloying and de-alloying reactions after the initial irreversible reduction from SnO2 to Li2O and metallic Sn. Here we report that a reversible conversion reaction, similar to that often observed in transition metal oxides, can occur in the cycling of the carbon-coated SnO2 hollow microspheres (SnO2/C), as is evidenced by Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and theoretical calculations. However, only alloying and de-alloying reactions can reversibly take place in carbon-free SnO2 hollow microspheres. The reversible capacity of the SnO2/C is even higher than the theoretical capacity of the free SnO2. These findings provide guidance to designing anode materials with higher reversible capacities. © 2012 Published by Elsevier B.V. All rights reserved.


Jung K.-N.,Korea Institute of Energy Research | Jung J.-H.,Korea Institute of Energy Research | Im W.B.,Chonnam National University | Yoon S.,Korea Institute of Energy Research | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2013

Rechargeable metal-air batteries have attracted a great interest in recent years because of their high energy density. The critical challenges facing these technologies include the sluggish kinetics of the oxygen reduction-evolution reactions on a cathode (air electrode). Here, we report doped lanthanum nickelates (La2NiO4) with a layered perovskite structure that serve as efficient bifunctional electrocatalysts for oxygen reduction and evolution in an aqueous alkaline electrolyte. Rechargeable lithium-air and zinc-air batteries assembled with these catalysts exhibit remarkably reduced discharge-charge voltage gaps (improved round-trip efficiency) as well as high stability during cycling. © 2013 American Chemical Society.


Song Y.,Chonnam National University | Kim H.,University of Tennessee at Knoxville
International Journal of Applied Geospatial Research | Year: 2015

The subway is one of the major passenger transport systems in Seoul, Korea. Over the last 30 years, the subway system has interacted with urban land use. This study aims to describe the subway system evolution and reveal the causal relations with land rent and population distributions in conjunction with the evolution of the subway system. Extensive and rapid expansion of subway networks have increased subway accessibility in all regional areas over time and have simultaneously strengthened the status of Central Business Districts (CBDs). These facts indirectly imply a possible strong association amongst land rent, population, and subway accessibility. To reveal these relationships, the Granger-causality test in vector auto-regression form is employed. The results confirm the hypothesis of a causal relationship, the influence of the subway accessibility to the land rent in nearby CBD areas. However, inverse causality also exists between these two variables, implying a more complex relationship. In contrast, population variables have a comparably weak causal relationship with subway accessibility in the spatial context of the subway system in Seoul. Copyright © 2015, IGI Global.


Atopic dermatitis (AD) is a heterogeneous disease that manifests with a wide variety of clinical symptoms and signs. Due to the lack of definitive biomarkers for AD, it is very difficult to set up standard diagnostic criteria for AD which cover the entire spectrum of AD patients. Various instruments have been proposed for AD diagnosis, and they can be classified into a hospital setting or a community setting. From the preventive medicine viewpoint, questionnaire-based diagnostic criteria in a community setting are important to detect and manage childhood AD patients properly. In this article, various diagnostic criteria for AD in hospital and community settings will be reviewed. Additionally, the Reliable Estimation of Atopic Dermatitis in Childhood (REACH), a new full questionnaire-based diagnostic tool for childhood AD, will be reviewed. © 2016 Japanese Dermatological Association.


Han J.Y.,Korea Advanced Institute of Science and Technology | Im W.B.,Chonnam National University | Lee G.-Y.,Korea Advanced Institute of Science and Technology | Jeon D.Y.,Korea Advanced Institute of Science and Technology
Journal of Materials Chemistry | Year: 2012

A novel yellow-emitting phosphor, Na 3K(Si 1-xAl x) 8O 16±δ:Eu 2+, peaking at 555 nm was synthesized and evaluated as a candidate for white-emitting LEDs. The structure refinement, luminescence properties of Na 3K(Si 1-xAl x) 8O 16±δ:Eu 2+ phosphors as well as their thermal quenching and the fabrication of white-emitting LEDs were for the first time investigated. By partially substituting Si 4+ with Al 3+, the emission peak was shifted from 553 nm to 573 nm, giving a greenish yellow-yellow color, due to the splitting of the 5d energy level of Eu 2+. By using a near-UV LED (395 nm) and a mixture of yellow-emitting Na 3K(Si 1-xAl x) 8O 16±δ:Eu 2+ phosphor and blue-emitting BaMgAl 10O 17:Eu 2+ phosphor as light converters, we constructed an intense white-light-emitting LED. The white-light-emitting LED exhibited an excellent color-rendering index R a of 90 at a correlated color temperature of 5952 K with CIE coordinates of (0.33, 0.29). The results of the white-emitting LED package combining 395 nm near UV chip with Y/B phosphors demonstrated the potential of the yellow-emitting Na 3K(Si 1-xAl x) 8O 16±δ:Eu 2+ phosphor for UV LED application. © 2012 The Royal Society of Chemistry.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

The asymmetric unit of the title compound, K2[Pd(NCS) 4]·2[Pd(NCS)2(C8H6N 4)], contains two crystallographically independent half-molecules of the anionic PdII complex, two K+ cations and two independent neutral PdII complexes; an inversion centre is located at the centroid of each anionic complex. In the anionic complexes, each Pd II ion is four-coordinated in an almost regular square-planar environment by four S atoms from four SCN- anions, and the PdS4 unit is exactly planar. In the neutral complexes, the PdII ion has a slightly distorted square-planar coordination environment defined by two pyrimidine N atoms derived from a chelating 2,2′-bipyrimidine ligand and two mutually cis S atoms from two SCN- anions. Both 2,2′-bipyrimidine ligands are almost planar [dihedral angle between the rings = 3.98 (16) and 4.57 (17)°] and also chelate to a potassium ion from their other two N atoms. In the crystal, the K+ ions inter-act with various S and N atoms of the ligands, forming a three-dimensional polymeric network, in which the shortest K⋯K contacts between the KN7S polyhedra are 4.4389 (17) and 4.4966 (18) Å. Intra- and inter-molecular C - H⋯S and C - H⋯N hydrogen bonds are also observed. © Kwang Ha 2012.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title complex, trans-[PtCl2(C9H 7N)2], the PtII ion is four-coordinated in an essentially square-planar coordination environment defined by two N atoms from two quinoline (qu) ligands and two Cl- anions. The Pt atom is located on an inversion centre and thus the asymmetric unit contains one half of the complex; the PtN2Cl2 unit is exactly planar. The dihedral angle between the PtN2Cl2 unit and the quinoline ligand is 85.1 (1)°. In the crystal, the complex molecules are stacked into columns along the b axis. In the columns, several inter-molecular π-π inter-actions between the six-membered rings are present, the shortest ring centroid-centroid distance being 3.733 (5) Å between pyridine rings. © Kwang Ha 2012.


Hwang W.-Y.,Chonnam National University | Hwang W.-Y.,University of Waterloo | Gittsovich O.,University of Waterloo
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

Recently, Pawlowski claimed to have proven the security of a quantum key distribution by using only the monogamy of Bell's inequality violations. In the proof, however, he tacitly assumed that the eavesdropper's outcome is binary. The assumption cannot be justified because Eve's (eavesdropper's) power can only be limited by natural principle. We provide a counterexample for a step of the proof. ©2012 American Physical Society.


Noh H.-R.,Chonnam National University | Moon H.S.,Pusan National University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We clarify an interpretation of transmittance signals in ladder-type atomic systems by discriminating the contributions of one-photon resonance, two-photon resonance, and a mixed term of both in the calculated spectra for these ladder-type multilevel atoms. When the two-photon-resonance effect is distinguished from an accurate spectrum calculated by modeling ladder-type electromagnetically-induced transparency for the 5S 1/2-5P 3/2-5D 5/2 transitions of 87Rb atoms, we find that the transmittance signals for the 5D 5/2(F ′ ′=2,3) states are mainly composed of the mixed term related not to pure-two-photon atomic coherence but to the optical-pumping effect whereas the transmittance signal for the 5D 5/2(F ′ ′=4) state originates from both the pure-two-photon-resonance term and the mixed term. © 2012 American Physical Society.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2012

C22H21Cl5N2OPt, monoclinic, P121/c1 (no. 14), a = 7.2901(5) Å, b = 21.941(2) Å, c = 29.264(2) Å, + = 92.829(2)°, V = 4675.2 Å3, Z = 8, Rgt(F) = 0.046, wRref(F2) = 0.098, T = 200 K. © 2012 by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2012

C22H20Cl4N2OPt, monoclinic, P121/c1 (no. 14), a = 14.157(1) Å, b = 9.1855(8) Å, c = 17.053(1) Å, β = 92.039(2)°, V = 2216.2 Å3, Z = 4, Rgt(F) = 0.037, wRref(F2) = 0.086, T = 200 K. © 2012 by Oldenbourg Wissenschaftsverlag, München.


Ha K.,Chonnam National University
Zeitschrift fur Kristallographie - New Crystal Structures | Year: 2012

C18H20Cl6N2O2Pt, triclinic, P1 (no. 2), a = 7.2602(6) Å, b = 8.0823(7) Å, c = 10.6370(9) Å, , = 78.774(2)°, β = 70.177(2)°, γ = 79.724(2)°, V = 571.7 Å3, Z = 1, Rgt(F) = 0.042, wRref(F2) = 0.106, T = 200 K. © 2012 by Oldenbourg Wissenschaftsverlag, München.


Han J.Y.,Korea Advanced Institute of Science and Technology | Im W.B.,Chonnam National University | Kim D.,Korea Advanced Institute of Science and Technology | Cheong S.H.,Korea Advanced Institute of Science and Technology | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

A new color-tunable Eu 2+-doped sodium aluminium silicate, Na 2-x-yAl 2-xSi xO 4:yEu 2+ (0 ≤ x ≤ 1), phosphor system was investigated as a novel candidate for phosphor-converted white light-emitting diode (LED) applications and successfully synthesized by wet chemical methods based on the hydrolysis of tetraethyl orthosilicate (TEOS). Different crystal structures and emission spectra were obtained by varying the ratio of Al to Si in the phosphor Na 2-xAl 2-xSi xO 4 with x value ranging from 0.25 to 0.55. The Na 2-x-yAl 2-xSi xO 4:yEu 2+ phosphor system emitted a maximum intensity at 470-600 nm when using a 395 nm excitation wavelength, and the emission was strongly affected by the crystal structures determined by the x value. Substitution of Eu 2+ affected the center wavelength and emission intensity due to changes in the crystal-field effect, which was strongly dependent on the crystal structure. The LED device exhibited an excellent color-rendering index R a of 93 at a correlated color temperature of 4258 K with CIE color coordinates of (0.3629, 0.3427) under a 20 mA forward-bias current. Based on these results, we are currently evaluating the potential application of Na 2-x-yAl 2-xSi xO 4:yEu 2+ as a white-emitting UV-convertible phosphor. © The Royal Society of Chemistry 2012.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title compound, [PtCl 2(C 9H 7N) 2]·CH 3NO 2, the Pt II cation is four-coordinated in an essentially square-planar environment by two N atoms from two quinoline ligands and two Cl - anions. One of the nearly planar quinoline ligands [maximum deviations = 0.042 (6) and 0.018 (7) Å] is almost perpendicular to the PtCl 2N 2 unit [maximum deviation = 0.024 (3) Å], making a dihedral angle of 89.6 (1)°, whereas the other is slightly inclined to the central plane with a dihedral angle of 74.1 (1)°. The dihedral angle between the quinoline ligands is 88.3 (2)°. In the crystal, each solvent mol-ecule is linked to the metal complex by weak inter-molecular C-H⋯O hydrogen bonds.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title complex, [Pd(C 7H 3NO 4)(C 13H 9N)], the Pd II ion is four-coordinated in a distorted square-planar environment by one N and two O atoms from the tridentate pyridine-2,6-dicarboxyl-ate (dipic) anionic ligand and one N atom of the acridine (acr) ligand. The dipic and acr ligands are nearly planar [maximum deviation = 0.069 (3) Å in dipic and 0.091 (4) Å in acr] and the dihedral angle between their mean planes is 58.67 (7)°. The Pd-O bond lengths are nearly equal, but the Pd-N bond lengths are slightly different. There is a short C-H⋯O inter-action in the mol-ecule involving the two ligands. In the crystal, complex mol-ecules are linked through C-H⋯O inter-actions, forming a three-dimensional network. There are also a number of inter-molecular π-π inter-actions present, the shortest ring centroid-centroid distance being 3.622 (3) Å.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

The asymmetric unit of the title compound, [Pt(C 10H 9N 3) 2]Br 2·H 2O, contains two crystallographically independent half-mol-ecules of the cationic Pt II complex, two Br - anions and a lattice water mol-ecule; an inversion centre is located at the centroid of each complex. Each Pt II ion is four-coordinated in an essentially square-planar environment by four pyridine N atoms derived from the two chelating di-2-pyridyl-amine (dpa) ligands, and the PtN 4 unit is exactly planar. The chelate ring formed by the dpa ligand displays a boat conformation, with dihedral angles between the pyridine rings of 35.9 (2) and 41.0 (2)°. The complex cations, Br - anions and solvent water mol-ecules are linked by O-H⋯Br, N-H⋯Br, C-H⋯O and C-H⋯Br hydrogen bonds, forming a three-dimensional network.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

The Pt II ion in the title complex, [PtI 2(C 10H 9N 3)], is four-coordinated in a distorted square-planar environment defined by the two pyridine N atoms of the chelating di-2-pyridyl-amine (dpa) ligand and by two I - anions. The dpa ligand is not planar, the dihedral angle between the pyridine rings being 52.8 (3)°. Pairs of complex mol-ecules are assembled through inter-molecular N-H⋯I hydrogen bonds, forming a dimer-type species. The complexes are stacked in columns along the b axis and display several inter-molecular π-π inter-actions between the pyridine rings, with a shortest ring centroid-centroid distance of 3.997 (5) Å.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

The asymmetric unit of the title compound, [Pd(C 10H 9N 3) 2](NO 3) 2, contains one half of a cationic Pd II complex and one NO 3 - anion. In the complex, the Pd II ion is four-coordinated by four pyridine N atoms derived from the two chelating dipyridin-2-yl-amine (dpa) ligands. The Pd II atom is located on an inversion centre, and thus the PdN 4 unit is exactly planar. The dpa ligand itself is not planar, showing a dihedral angle between the pyridine rings of 39.9 (1)°. The anions are connected to the complex by inter-molecular N-H⋯O hydrogen bonds between the two O atoms of the anion and the N-H group of the cation. Weak inter-molecular C-H⋯O hydrogen bonds additionally link the constituents in the crystal structure. The NO 3 - anion was found to be disordered over two sites with a site-occupancy factor of 0.55 (10) for the major component.


Ha K.,Chonnam National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

The title compound, C17H20N2O3, is a Schiff base, which is found as a zwitterion in the solid state. The geometry around the iminium N atom indicates sp 2-hybridization. The zwitterion shows a strong intra-molecular N-H⋯O hydrogen-bond inter-action between the iminium N atom and the phenolate O atom.


Shin S.Y.,Konkuk University | Choi C.,Chonnam National University | Lee H.G.,Konkuk University | Lim Y.,Konkuk University | Lee Y.H.,Konkuk University
Carcinogenesis | Year: 2012

Interleukin-11 (IL-11), which belongs to a class of IL6-type cytokines, plays an important role in inflammation, motility and invasion in cancer. The ras mutation is frequently found in human cancer, but little is known regarding the transcriptional activation of the IL-11 gene by t