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Seoul, South Korea

Konkuk University is a private university located in Seoul and Chungju. The Seoul campus is located in the southeastern part of Seoul, near the Han River, and is served by a metro station of the same name. The university possesses accreditation from the South Korean Ministry of Culture and Education. The university emphasizes technology and science majors and research. Wikipedia.

Huang B.,Tsinghua University | Huang B.,National Renewable Energy Laboratory | Lee H.,Konkuk University
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

In this paper, we have systematically studied the structural and electronic properties of vacancy defects and carbon impurity in hexagonal boron nitride (h-BN) by using both normal GGA calculations and advanced hybrid functional calculations. Our calculations show that the defect configurations and the local bond lengths around defects are sensitive to their charge states. The highest negative defect charge states are largely determined by the nearly-free-electron state at the conduction band minimum of BN. Generally, the in-gap defect levels obtained from hybrid functional calculations are much deeper than those obtained from normal GGA calculations. The formation energies of neutral defects calculated by hybrid functional and GGA are close to each other, but the defect transition energy levels are quite different between GGA and hybrid functional calculations. Finally, we show that the charged defect configurations as well as the transition energy levels exhibit interesting layer effects. © 2012 American Physical Society. Source

Lee Y.-S.,CHA Medical University | Kim T.-S.,CHA Medical University | Kim D.-K.,Konkuk University
BMC Cancer | Year: 2011

Background: Although the graft-versus-tumor (GVT) effect of donor-derived T cells after allogeneic hematopoietic stem cell transplantation has been used as an effective adoptive immunotherapy, the antitumor effects of cord blood (CB) transplantation have not been well studied.Methods: We established the animal model by transplantation of CB mononuclear cells and/or tumor cells into NOD/SCID mice. The presence of CB derived T cells in NOD/SCID mice or tumor tissues were determined by flow cytometric and immunohistochemical analysis. The anti-tumor effects of CB derived T cells against tumor was determined by tumor size and weight, and by the cytotoxicity assay and ELISPOT assay of T cells.Results: We found dramatic tumor remission following transfer of CB mononuclear cells into NOD/SCID mice with human cervical tumors with a high infiltration of CD3+T cells in tumors. NOD/SCID mice that receive neonatal CB transplants have reconstituted T cells with significant antitumor effects against human cervical and lung tumors, with a high infiltration of CD3+T cells showing dramatic induction of apoptotic cell death. We also confirmed that T cells showed tumor specific antigen cytotoxicity in vitro. In adoptive transfer of CD3+T cells into mice with pre-established tumors, we observed much higher antitumor effects of HPV-specific T cells by ELISPOT assays.Conclusions: Our results show that CB derived T lymphocytes will be useful for novel immunotherapeutic candidate cells for therapy of several tumors in clinic. © 2011 Lee et al; licensee BioMed Central Ltd. Source

Jung II S.,Sloan Kettering Cancer Center | Jung II S.,Konkuk University | Donati O.F.,Sloan Kettering Cancer Center | Donati O.F.,University of Zurich | And 4 more authors.
Radiology | Year: 2013

Purpose: To evaluate the incremental value of using diffusionweighted magnetic resonance (MR) imaging in addition to T2-weighted imaging for the detection of prostate cancer in the transition zone and the assessment of tumor aggressiveness. Materials and Methods: This retrospective HIPAA-compliant institutional review board Capproved study included 156 consecutive patients (median age, 59.2 years) who underwent MR imaging before radical prostatectomy. Two readers who were blinded to patient data independently recorded their levels of suspicion on a five-point scale of the presence of transition zone tumors on the basis of T2-weighted imaging alone and then, 4 weeks later, diffusion-weighted imaging and T2-weighted imaging together. Apparent diffusion coefficients (ADCs) were measured in transition zone cancers and glandular and stromal benign prostatic hyperplasia. Areas under the receiver operating characteristic curves were used to evaluate detection accuracy, and generalized linear models were used to test ADC differences between benign and malignant prostate regions. Whole-mount step-section histopathologic examination was the reference standard. Results: In overall tumor detection, addition of diffusion-weighted imaging to T2-weighted imaging improved the areas under the receiver operating characteristic curves for readers 1 and 2 from 0.60 and 0.60 to 0.75 and 0.71, respectively, at the patient level (P =.004 for reader 1 and P =.027 for reader 2) and from 0.64 and 0.63 to 0.73 and 0.68, respectively, at the sextant level (P =.001 for reader 1 and P =.100 for reader 2). Least squares mean ADCs (× 10-3mm2/sec) in glandular and stromal benign prostatic hyperplasia were 1.44 and 1.09, respectively. Mean ADCs were inversely associated with tumor Gleason scores (1.10, 0.98, 0.87, and 0.75 for Gleason scores of 3 + 3, 3 + 4, 4 + 3, and ≥ 4 + 4, respectively). Conclusion: Use of diffusion-weighted imaging in addition to T2-weighted imaging improved detection of prostate cancer in the transition zone, and tumor ADCs were inversely associated with tumor Gleason scores in the transition zone. q RSNA, 2013 © RSNA, 2013. Source

Moon E.-Y.,Sejong University | Lee Y.-S.,Sejong University | Choi W.S.,Konkuk University | Lee M.-H.,Sejong University
Experimental Cell Research | Year: 2011

B-cell activating factor (BAFF) plays a role in the generation and the maintenance of mature B cells. Lipopolysaccharide (LPS) increased BAFF expression through the activation of toll-like receptor 4 (TLR4)-dependent signal transduction. Here, we investigated the mechanism of action on mouse BAFF (mBAFF) expression by cAMP production in Raw264.7 mouse macrophages. mBAFF expression was increased by the treatment with a cAMP analogue, dibutyryl-cAMP which is the activator of protein kinase A (PKA), cAMP effector protein. PKA activation was measured by the phosphorylation of cAMP-response element binding protein (CREB) on serine 133 (S133). cAMP production and CREB (S133) phosphorylation were augmented by LPS-stimulation. While mBAFF promoter activity was enhanced by the co-transfection with pS6-RSV-CREB, it was reduced by siRNA-CREB. PKA inhibitor, H-89, reduced CREB (S133) phosphorylation and mBAFF expression in control and LPS-stimulated macrophages. Another principal cAMP effector protein is cAMP-responsive guanine nucleotide exchange factor (Epac), a Rap GDP exchange factor. Epac was activated by the treatment with 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (CPT), Epac activator, as judged by the measurement of Rap1 activation. Basal level of mBAFF expression was increased by CPT treatment. LPS-stimulated mBAFF expression was also slightly enhanced by co-treatment with CPT. In addition, dibutyryl-cAMP and CPT enhanced mBAFF expression in bone marrow-derived macrophages (BMDM). With these data, it suggests that the activation of PKA and cAMP/Epac1/Rap1 pathways could be required for basal mBAFF expression, as well as being up-regulated in the TLR4-induced mBAFF expression. © 2011 Elsevier Inc. Source

Lee J.,Konkuk University | Lee J.,Plant Genomics and Breeding Institute | Koh H.-J.,Plant Genomics and Breeding Institute
Proteome Science | Year: 2011

Background: Although a great deal of rice proteomic research has been conducted, there are relatively few studies specifically addressing the rice grain proteome. The existing rice grain proteomic researches have focused on the identification of differentially expressed proteins or monitoring protein expression patterns during grain filling stages.Results: Proteins were extracted from rice grains 10, 20, and 30 days after flowering, as well as from fully mature grains. By merging all of the identified proteins in this study, we identified 4,172 non-redundant proteins with a wide range of molecular weights (from 5.2 kDa to 611 kDa) and pI values (from pH 2.9 to pH 12.6). A Genome Ontology category enrichment analysis for the 4,172 proteins revealed that 52 categories were enriched, including the carbohydrate metabolic process, transport, localization, lipid metabolic process, and secondary metabolic process. The relative abundances of the 1,784 reproducibly identified proteins were compared to detect 484 differentially expressed proteins during rice grain development. Clustering analysis and Genome Ontology category enrichment analysis revealed that proteins involved in the metabolic process were enriched through all stages of development, suggesting that proteome changes occurred even in the desiccation phase. Interestingly, enrichments of proteins involved in protein folding were detected in the desiccation phase and in fully mature grain.Conclusion: This is the first report conducting comprehensive identification of rice grain proteins. With a label free shotgun proteomic approach, we identified large number of rice grain proteins and compared the expression patterns of reproducibly identified proteins during rice grain development. Clustering analysis, Genome Ontology category enrichment analysis, and the analysis of composite expression profiles revealed dynamic changes of metabolisms during rice grain development. Interestingly, we detected that proteins involved in glycolysis, TCA-cycle, lipid metabolism, and proteolysis accumulated at higher levels in fully mature grain compared to grain developing stages, suggesting that the accumulation of these proteins during the desiccation stage may be associated with the preparation of proteins required in germination. © 2011 Lee and Koh; licensee BioMed Central Ltd. Source

Cho Y.,Konkuk University | Labella T.,Virginia Polytechnic Institute and State University | Lai J.-S.,Virginia Polytechnic Institute and State University | Senesky M.K.,Texas Instruments
IEEE Transactions on Industrial Electronics | Year: 2014

This paper proposes a pulsewidth-modulation strategy to achieve balanced line-to-line output voltages and to maximize the modulation index in the linear modulation range where the output voltage can be linearly adjusted in the multilevel cascaded inverter (MLCI) operating under unbalanced dc-link conditions. In these conditions, the linear modulation range is reduced, and a significant output voltage imbalance may occur as voltage references increase. In order to analyze these effects, the voltage vector space for MLCI is evaluated in detail. From this analysis, the theory behind the output voltage imbalance is explained, and the maximum linear modulation range considering an unbalanced dc-link condition is evaluated. After that, a neutral voltage modulation strategy is proposed to achieve output voltage balancing as well as to extend the linear modulation range up to the maximum reachable point in theory. In the proposed method, too large of a dc-link imbalance precludes the balancing of the output voltages. This limitation is also discussed. Both the simulations and the experiments for a seven-level phase-shifted modulated MLCI for electric vehicle traction motor drive show that the proposed method is able to balance line-to-line output voltages as well as to maximize the linear modulation range under the unbalanced dc-link conditions. © 1982-2012 IEEE. Source

Lee B.U.,Konkuk University
Aerosol and Air Quality Research | Year: 2011

Air is filled with numerous tiny organisms, with sizes ranging from 50 nm to 10 μm. These organisms are called airborne biological particles or bioaerosols. In the human history of investigating the origin of life and fighting against contagious diseases, the recognition of bioaerosols and the development of control methods against them have played crucial roles. The pandemic outbreak of flu due to the influenza A H1N1 virus in 2009 and the bio-terror incidents in 2001 have alerted us to the importance of bioaerosol research. Here, control methods against bioaerosols are briefly reviewed, and suggestions are offered for future research on airborne biological particles. © Taiwan Association for Aerosol Research. Source

Oh K.-J.,Konkuk University | Goodman S.B.,Stanford University | Yang J.-H.,Seoul Veterans Hospital
Journal of Arthroplasty | Year: 2011

A randomized, prospective, comparative study was performed in 2 related, adjacent generation posterior stabilized total knee prostheses, to evaluate whether the newer design improved the clinical and radiographic outcome for treatment of advanced osteoarthritis of the knee. Ninety one total knee arthroplasties in 84 patients (45 Insall-Burstein II and 46 NexGen Legacy posterior stabilized [both from Zimmer, Warsaw, Ind] prostheses) with an average of 10.3 years of follow-up (range, 9-11.8 years) were included. The preoperative diagnoses were primary osteoarthritis in all patients. At the latest evaluation, there were no significant differences detected in the mean clinical and functional knee scores, average postoperative active range of motion, and anterior knee pain between the Insall-Burstein II and the NexGen Legacy groups postoperatively. © 2011 Elsevier Inc. Source

Chung S.W.,Konkuk University | Song B.W.,Nalgae Hospital | Kim Y.H.,Anjung Seoul Jeil Hospital | Park K.U.,Seoul National University | Oh J.H.,Seoul National University
American Journal of Sports Medicine | Year: 2013

Background: The rate of healing failure after surgical repair of chronic rotator cuff tears is considerably high. Purpose: To verify the effect of platelet-rich plasma (PRP) with and without porcine dermal collagen graft augmentation on tendon-to-bone healing, using the rabbit supraspinatus tendon. Study Design: Controlled laboratory study. Methods: A total of 80 rabbits were randomly allocated into 4 groups (20 rabbits per group: 12 for histological and 8 for mechanical testing): repair (R), repair 1 patch augmentation (RPa), repair 1 PRP (RPr), and repair 1 patch 1 PRP (RPaPr). The right shoulder was used for experimental interventions, and the left served as a control. Six weeks after the detachment of the supraspinatus, the torn tendon was repaired in a transosseous manner, simulating double-row repair in all groups. Platelet-rich plasma was prepared and applied onto the repair site in the RPr and RPaPr groups, and the patch was used to augment the repair in the RPa and RPaPr groups. The mechanical tensile strength test was performed at 8 weeks after repair and the histological evaluation at 4 and 8 weeks. Results: At 4 weeks, the collagen fibers were poorly organized, and fiber continuity was not established in all groups. However, vascularity and cellularity were higher with granulation tissue formation in the PRP-treated groups (RPr and RPaPr) than the nontreated groups (R and RPa). At 8 weeks, tendon-to-bone integration was much improved with more collagen fibers, and longitudinally oriented collagen fibers were visible in all groups. The PRP-treated groups showed better collagen fiber continuity and orientation than the nontreated groups; however, no distinctive difference was found between the patch-augmented groups (RPa and RPaPr) and nonaugmented groups (R and RPr). The mean load-to-failure results were 61.57 ± 29.99 N, 76.84 ± 16.08 N, 105.35 ± 33.82 N, and 117.93 ± 12.60 N for the R, RPa, RPr, and RPaPr groups, respectively, and they were significantly different between the R and RPr (P = .018), R and RPaPr (P = .002), and RPa and RPaPr (P = .029) groups. Conclusion: This animal study showed the enhancement of tendon-to-bone healing after local administration of autologous PRP assessed by histological and biomechanical testing in a rabbit model of chronic rotator cuff tears. However, there was little additive effect of the patch graft. Clinical Relevance: The use of PRP might be a biological supplement to increase the rotator cuff healing rate, which still remains low even after successful cuff repair, but this result should be interpreted with caution regarding clinical applications. © 2013 The Author(s). Source

Yoon J.H.,Konkuk University
Journal of the Korean Physical Society | Year: 2014

I apply the Hamiltonian reduction procedure to general spacetimes of 4 dimensions in the (2+2) formalism and find privileged spacetime coordinates in which the physical Hamiltonian is expressed in terms of the conformal two metric and its conjugate momentum. Physical time is the area element of the spatial cross-section of null hypersurfaces, and the physical radial coordinate is defined by equipotential surfaces on a given spacelike hypersurface of constant physical time. The physical Hamiltonian is local and positive in the privileged coordinates. I present the complete set of Hamilton's equations and find that they coincide with the Einstein's equations written in the privileged coordinates. This shows that the Hamiltonian reduction is self-consistent and respects general covariance. © 2014 The Korean Physical Society. Source

Lee K.Y.,Konkuk University
Fuzzy Sets and Systems | Year: 2016

The paper is concerned with approximation properties which are defined in fuzzy normed spaces. First, we introduce the approximation property and the bounded approximation property. Next, we provide two main examples: First example is a fuzzy normed space that does not have the approximation property and second example is a fuzzy normed space with the approximation property that does not have the bounded approximation property. Finally, we provide characterizations of approximation properties in fuzzy normed spaces. © 2015 Elsevier B.V. Source

Kim Y.-B.,Konkuk University
Electronics Letters | Year: 2014

The primary task of radio-frequency identification (RFID) readers is to identify multiple objects as quickly and reliably as possible with minimal power consumption and computation. An optimisation problem related to the selection of appropriate frame sizes for the framed slotted ALOHA protocol, commonly used in passive RFID tag identification systems, is considered. The fundamental question concerning this issue is: what frame size is most suitable for identifying as many tags as possible in a given time? More formally, what is the optimal value for frame sizes in the sense that the probability of successful identification is maximised? Thus far, many research results related to this problem have been reported in the literature, but most are either suboptimal or empirical. Through asymptotic analysis, it is shown that the optimal frame size is approximately given by N/ln 2 for N tags. © The Institution of Engineering and Technology 2014. Source

Kim H.,Konkuk University | Yokoyama W.,Albany Research Center | Davis P.A.,University of California at Davis
Journal of Medicinal Food | Year: 2014

Dietary changes could potentially reduce prostate cancer morbidity and mortality. Transgenic adenocarcinoma of the mouse prostate (TRAMP) prostate tumor responses to a 100'g of fat/kg diet (whole walnuts, walnut oil, and other oils; balanced for macronutrients, tocopherols [α-And γ]) for 18 weeks ad libitum were assessed. TRAMP mice (n=17 per group) were fed diets with 100'g fat from either whole walnuts (diet group WW), walnut-like fat (diet group WLF, oils blended to match walnut's fatty acid profile), or as walnut oil (diet group WO, pressed from the same walnuts as WW). Fasted plasma glucose was from tail vein blood, blood was obtained by cardiac puncture, and plasma stored frozen until analysis. Prostate (genitourinary intact [GUI]) was weighed and stored frozen at -80°C. Plasma triglyceride, lipoprotein cholesterol, plasma multianalyte levels (Myriad RBM Rat Metabolic MAP), prostate (GUI), tissue metabolites (Metabolon, Inc., Durham, NC, USA), and mRNA (by Illumina NGS) were determined. The prostate tumor size, plasma insulin-like growth factor-1 (IGF-1), high density lipoprotein, and total cholesterol all decreased significantly (P<.05) in both WW and WO compared to WLF. Both WW and WO versus WLF showed increased insulin sensitivity (Homeostasis Model Assessment [HOMA]), and tissue metabolomics found reduced glucose-6-phosphate, succinylcarnitine, and 4-hydroxybutyrate in these groups suggesting effects on cellular energy status. Tissue mRNA levels also showed changes suggestive of altered glucose metabolism with WW and WO diet groups having increased PCK1 and CIDEC mRNA expression, known for their roles in gluconeogenesis and increased insulin sensitivity, respectively. WW and WO group tissues also had increased MSMB mRNa a tumor suppressor and decreased COX-2 mRNA, both reported to inhibit prostate tumor growth. Walnuts reduced prostate tumor growth by affecting energy metabolism along with decreased plasma IGF-1 and cholesterol. These effects are not due to the walnut's N-3 fatty acids, but due to component(s) found in the walnut's fat component. © 2014, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2014. Source

Kim S.-K.,Konkuk University | Park J.H.,Seoul National University
Journal of Ginseng Research | Year: 2011

A total of 470 papers directly related to research on the Panax species were retrieved by performing internet searches with the keywords Panax and ginseng as the search terms. The publications were categorized as follows: 399 research articles, 30 reviews, 30 meeting abstracts, 7 proceedings, and 4 letters. The majority of these publications were published by scientists from Korea (35.7%), China (32.3%), and the USA (11.3%). Scientists from a total of 29 nations were actively involved in conducting ginseng research. A total of 43.6% of the publications were categorized as pharmacodynamic studies. The effects of ginseng on cerebrovascular function and cancer were the two most common topics considered in the pharmacodynamic studies. More than half of the ginseng studies assessed the use of P. ginseng. A total of 23 countries participated in studies specifically related to P. ginseng, and more than 80% of these studies originated from Korea and China. A total of 50 topics within the pharmacodynamics category were examined in association with the use of P. ginseng. © The Korean Society of Ginseng. Source

Jin X.,Korea University | Yin J.,Seoul National University | Kim S.-H.,Korea University | Sohn Y.-W.,Korea University | And 5 more authors.
Cancer Research | Year: 2011

Aberrant activation of receptor tyrosine kinases (RTK) is causally linked to the pathobiological traits of glioblastoma and genesis of glioma stem-like cells (GSC), but the underlying mechanism is still unknown. Here, we show that epidermal growth factor receptor (EGFR) signaling regulates the proliferation, angiogenesis, and acquisition of GSC characteristics by inducing inhibitor of differentiation 3 (ID3) and ID3-regulated cytokines [GRO1 and interleukins (IL)-6 and 8] induction. We found that EGFR-mediated ID3 expression was regulated by Smad5, which was directly phosphorylated by AKT. Furthermore, ID3 alone imparted GSC features to primary astrocytes derived from Ink4a/Arf-deficient mouse, and EGFR-ID3-IL-6 signaling axis gave rise to tumor cell heterogeneity. Conversely, EGFR inhibitors suppressed EGFR-AKT-Smad5-driven induction of ID3, which led to a decrease in the tumorsphere forming ability of GSCs and U87MG cells that possess an active mutant EGFR, EGFRvIII, without obvious cytotoxic effects. However, these cells seemed to regain colonogenic ability after removal of the EGFR inhibitors. Together, the results delineate a novel integrative molecular mechanism in which the RTK-ID signaling pathway governs genesis and maintenance of GBM histopathologic features, such as GSCs-based tumor initiation, progression, and angiogenesis. ©2011 AACR. Source

Choi Y.H.,Chonnam National University | Gu Y.-M.,Chonnam National University | Oh J.-W.,Konkuk University | Lee K.-Y.,Chonnam National University
Biochemical and Biophysical Research Communications | Year: 2011

Osterix (Osx) is a novel zinc finger-containing transcription factor that is essential for osteoblast differentiation and bone formation in bone homeostasis. The mitogen-activated protein (MAP) kinases are a group of evolutionarily conserved proline-directed protein serine/threonine kinases that are activated in response to a variety of extracellular stimuli and mediate signal transduction from the cell surface to the nucleus. Erk1/2 plays essential roles in osteoblast differentiation and in supporting osteoclastogenesis, but the precise molecular signaling mechanisms between Osterix and Erk1/2 are not known. We therefore focused on the relationship between Osterix and Erk1/2 during osteoblast differentiation because BMP signaling induces Erk activation in osteoblasts. We investigated the role of the MAPK pathway in regulating protein levels and transcriptional functions of Osterix. We found that Erk activation by overexpression of constitutively active MEK increased the mRNA and protein levels of Osterix and enhanced the transcriptional activity of Osterix, whereas U0126, an inhibitor of MEK, suppressed the protein levels of Osterix and the transcriptional activity. Also, overexpression of constitutively active MEK stabilized Osterix protein. These results suggest that Erk1/2 regulates a major transcription factor, Osterix, during osteoblast differentiation by increasing its protein stability and transcriptional activity. © 2011 Elsevier Inc. Source

Yoon J.H.,Konkuk University
Journal of Physics: Conference Series | Year: 2015

I apply the Hamiltonian reduction procedure to general spacetimes of 4 dimensions with no isometries in the (2+2) formalism and find privileged spacetime coordinates. Physical time is chosen as the area element of the two dimensional cross-section of null hypersurfaces. The physical spatial coordinates are defined by equipotential surfaces on a given spacelike hypersurface of constant physical time. The physical Hamiltonian is manifestly local and positive-definite in the privileged coordinates. The complete set of Hamilton's equations is presented and it is found that they coincide with the Einstein's equations written in the privileged coordinates. This shows that the Hamiltonian reduction is a self-consistent procedure. © Published under licence by IOP Publishing Ltd. Source

Hong G.P.,Chonnam National University | Min S.-G.,Konkuk University | Chin K.B.,Chonnam National University
Meat Science | Year: 2012

In this study, the effects of microbial transglutaminase (MTG) and calcium alginate (CA) systems in combination with soybean oil on the emulsion properties of porcine myofibrillar protein (MP) were evaluated under various pH conditions. MTG was shown to improve emulsifying capacity and creaming stability, which increased with increasing pH values up to 6.5. The CA did not influence emulsifying capacity, but it improved the creaming stability of the MP-stabilized emulsions. Both MTG and CA enhanced the rheological properties, but their effects on the physical characteristics of the protein evidenced an opposite trend in relation to pH, i.e., the MTG system improved both the emulsion and gelling properties with increasing pH, whereas the CA system was effective when the pH was lowered. By combining the two MP gelling systems, a stable and pH-insensible emulsion could be produced. © 2011 Elsevier Ltd. Source

Kil H.,Korea University | Nam W.,Konkuk University
International Journal of Web and Grid Services | Year: 2013

The web service composition problem aims to find an optimal composition of web services to satisfy a given request by using their syntactic and/or semantic features when no single service satisfies it. In particular, the semantics of services helps a composition engine identify more correct, complete and optimal candidates as a solution. In this paper, we study the web service composition problem considering semantic aspects, i.e., exploiting the semantic relationship between parameters of web services. Given a set of web service descriptions, their semantic information and a requirement web service, we find the optimal composition that contains the shortest path of semantically well connected web services which satisfies the requirement. Our techniques are based on semantic matchmaking and three model checking techniques such as Boolean satisfiability solving, symbolic model checking, and abstraction and refinement technique. In the experiment, our proposal efficiently identifies optimal compositions of web services. © 2013 Inderscience Enterprises Ltd. Source

Jeong B.R.,Gyeongsang National University | Sivanesan I.,Gyeongsang National University | Sivanesan I.,Konkuk University
Plant Cell, Tissue and Organ Culture | Year: 2015

Effects of plant growth regulators, light quality and sucrose on direct adventitious shoot regeneration, in vitro flowering and fruiting of Scrophularia takesimensis were investigated. The highest mean number of shoots per leaf (23.4), petiole (17.2) and stem (20.3) explants was obtained on Murashige and Skoog (MS) medium fortified with 2.0 mg l−1 BA and 1.0 mg l−1 IAA under white fluorescent light (WFL). Red light emitting diodes (LED) gave better shoot growth followed by WFL and blue LED. However, red LED treatment decreased the number of roots and induced callus at the base of shoot. The highest number of roots per shoot (9.2) and a maximum root length (8.9 cm) were obtained when the cultures were maintained under WFL. Somaclonal variation was observed when the shoot buds were cultured on the modified MS medium containing 1.0 mg l−1 IBA. The variant had variegated leaves in comparison with those of normal plantlets. The greatest frequency of flower induction (96.8 %) was obtained when the shoots were cultured on the modified MS medium containing 6.0 % (w/v) sucrose for 45 days under blue LED. The in vitro developed flowers self-fertilized and formed fruits. The culture media and environment had a positive effect on the content of phenolic compounds. Harpagoside content was high in seeds and low in shoots developed in MS medium containing BA. Among the light sources, shoots maintained under blue LED found to be best for harpagoside production (4.9 mg g−1) followed by WFL (3.3 mg g−1) and red LED (2.7 mg g−1). In vitro regenerated shoots had higher capacity to detoxify DPPH free radicals than field-grown plant samples. © 2015, Springer Science+Business Media Dordrecht. Source

Larson J.F.,KAIST | Park J.,Konkuk University
Telecommunications Policy | Year: 2014

This study examines the government leadership and strategic restructuring that guided The Republic of Korea's remarkable ICT-led development from 1980 to the present. That time span coincided with tumultuous political, social and economic transformation inside Korea including the growth of such powerful chaebol industry groups as Samsung, LG and SK. Globally, the period covered by this study featured the growth of new and more powerful digital networks epitomized by the internet. It also marked South Korea's transition from a development to a network state, allowing assessment of what the experience implies for developmental state theory. This research shows that the most convincing explanation for the decline of the Korean developmental state lies in its transformation into a network state. Nevertheless, it illustrates the continuing explanatory power of key concepts from the developmental state model, including a competent bureaucracy, a political system that allows the bureaucracy sufficient autonomy, market conforming methods for state intervention, and a "control tower," to guide industrial policy in the networked era. Korea's success suggests the value of technically trained leaders in the ICT sector, and in sharp contrast with Japan, the importance of the cross cultural experience and global outlook that many of them gained while studying at top universities in the U.S. For most of the three-plus decades in this study, the MIC served as Korea's control tower for the ICT sector, guiding policy and technology projects, and culminating in the 2006 U-Korea Master Plan, an ambitious blueprint for becoming the world's first ubiquitously networked nation. However, only two years later the Lee Myung-bak administration dismantled the ICT control tower in favor of a five year experiment with a liberal, market oriented approach to the ICT sector, much like policy in the United States. It was widely considered a failure and in 2013 President Park Geun-hye restored the control tower function within the new "super" Ministry of Science, ICT and Future Planning. The Korea experience also has more general implications for policymakers in the information age. These include the need for national, long-term policies, the vital role of education, ranging from highly specialized R&D to broadly-based public-private sector efforts to ensure demand for services. While Korea's past success depended heavily on the manufacture and export of hardware and infrastructure, the President Park Geun-hye administration, with its emphasis on building a "creative economy" signaled recognition that software, content and services will be more important than hardware in the future. © 2013 Elsevier Ltd. Source

This research aimed to develop an education program for public librarians and library users and to measure the effectiveness of this program to promote Consumer Health Information (CHI) service programs in libraries. This study provided CHI education for librarians and users and then examined how the education program affected their perception of CHI. After developing the education program, the author analyzed the change in perception, knowledge, and satisfaction of CHI in users and librarians before and after the program was administered. The author observed improvement in familiarity with CHI terminologies, knowledge of health-related websites and information sources, and ability to find health-related information on the Internet in both librarian and users groups. The research also revealed librarians' difficulty in providing CHI reference service and a possible solution: including education on CHI in the regular curriculum for public librarians. This study also provides content expectations for CHI education. © 2013 American Library Association. All rights reserved. Source

Yoon J.,Konkuk University | Park H.,Pohang University of Science and Technology | Kim K.,Pohang University of Science and Technology
Scientometrics | Year: 2013

Patent maps showing competition trends in technological development can provide valuable input for decision support on research and development (R&D) strategies. By introducing semantic patent analysis with advantages in representing technological objectives and structures, this paper constructs dynamic patent maps to show technological competition trends and describes the strategic functions of the dynamic maps. The proposed maps are based on subject-action-object (SAO) structures that are syntactically ordered sentences extracted using the natural language processing of the patent text; the structures of a patent encode the key findings of the invention and expertise of its inventors. Therefore, this paper introduces a method of constructing dynamic patent maps using SAO-based content analysis of patents and presents several types of dynamic patent maps by combining patent bibliographic information and patent mapping and clustering techniques. Building on the maps, this paper provides further analyses to identify technological areas in which patents have not been granted ("patent vacuums"), areas in which many patents have actively appeared ("technological hot spots"), R&D overlap of technological competitors, and characteristics of patent clusters. The proposed analyses of dynamic patent maps are illustrated using patents related to the synthesis of carbon nanotubes. We expect that the proposed method will aid experts in understanding technological competition trends in the process of formulating R&D strategies. © 2012 Akadémiai Kiadó, Budapest, Hungary. Source

Nile S.H.,Konkuk University
Journal of the Institute of Brewing | Year: 2015

Makgeolli is a traditional alcoholic beverage prepared from rice, barley, wheat or malt grains by fermentation using a natural starter called nuruk. The makgeolli flavour depends mainly on the content of the metabolic products (free sugars, amino acids, organic acids and aromatic compounds) produced during the fermentation of rice by moulds and yeasts. Compared with other alcoholic beverages, makgeolli contains high concentrations of nutrients, organic acids and 6-8% alcohol. Makgeolli is nutritious and is composed of 80% water, 2% protein, 0.8% carbohydrates, 0.1% fat and 10% dietary fibre, along with vitamins B and C, as well as a significant amount of lactobacilli and yeast. It has been reported that makgeolli has medicinal effects including antioxidant, anti-hypertensive, anti-diabetes and anti-cancer activities. Since makgeolli is a good source of vitamins, minerals, sugars, proteins, organic acids and free amino acids, as well as having significant medicinal importance, it can be considered a functional, medicinal and probiotic beverage. © 2015 The Institute of Brewing & Distilling. Source

The dependence of power amplifier (PA) backoff on resource allocation for non-contiguous carrier aggregation is investigated. To be specific, assuming two non-contiguous carriers, the power spectral density (PSD) of the third-order intermodulation distortion (IM3) is approximated as a function of power allocation and PSD allocation. Based on the closed-form expression, it is proven that the PSD of IM3 is maximised when the resource allocation is inversely proportional to the PSD allocation. The PA simulations verify that such resource allocation also maximises the PA backoff. © The Institution of Engineering and Technology 2013. Source

Kim J.,Korea Advanced Institute of Science and Technology | Lee H.-W.,Konkuk University | Chong S.,Korea Advanced Institute of Science and Technology
IEEE Journal on Selected Areas in Communications | Year: 2014

We study the coordinated transmission problem in cooperative cellular networks where a cluster of base stations forms a virtual cell to serve a mobile station (MS). The performance of such an MS-centric virtual cell network is dictated by the beamformer that enables to suppress interference; however, designing a beamformer is highly challenging due to the coupled nature of interference and desired signals under arbitrarily formed virtual cells. We develop a new formulation of the beamforming problem for sum-rate maximization in virtual cell networks and analyze the structure of its optimal solutions. Based on this analysis, we develop a beamforming algorithm that can balance between desired signal maximization and interference minimization, so as to maximize the sum-rate. We show through extensive simulations that our balanced beamforming algorithm mitigates edge user effect and outperforms existing algorithms in various scenarios where virtual cells are allowed to overlap. © 2014 IEEE. Source

Kim H.-S.,Konkuk University
Structural Design of Tall and Special Buildings | Year: 2013

An improved analysis method for column shortening of tall buildings has been proposed. The analysis method considers the restraining effects of steel bars and horizontal members. A step-by-step method was applied for the exact displacement and internal forces for any elapsed time. The sectional properties of the asymmetrically reinforced and cracked section were also taken into account. Column shortenings of an 80-story reinforced concrete frame-shear wall building were investigated as numerical examples. The horizontal members reduce the differential shortening between the adjacent vertical members and transfer the axial forces of more shortened vertical members to less shortened members. © 2011 John Wiley & Sons, Ltd. Source

Im J.-K.,Seoul National University | Son H.-S.,Konkuk University | Zoh K.-D.,Seoul National University
Journal of Hazardous Materials | Year: 2011

In this study, the removal of perchlorate (0.016mM) using Fe 0-only (325 mesh, 10gL -1) and Fe 0 (10gL -1) with UV (254nm) reactions were investigated under oxic and anoxic conditions (nitrogen purging). Under anoxic conditions, only 2% and 5.6% of perchlorate was removed in Fe 0-only and Fe 0/UV reactions, respectively, in a 12h period. However, under oxic conditions, perchlorate was removed completely in the Fe 0-only reaction, and reduced by 40% in the Fe 0/UV reaction, within 9h. The pseudo-first-order rate constant (k 1) was 1.63×10 -3h -1 in Fe 0-only and 4.94×10 -3h -1 in Fe 0/UV reaction under anoxic conditions. Under oxic conditions, k 1 was 776.9×10 -3h -1 in Fe 0-only reaction and 35.1×10 -3h -1 in the Fe 0/UV reaction, respectively. The chlorine in perchlorate was recovered as chloride ion in Fe 0-only and Fe 0/UV reactions, but lower recovery of chloride under oxic conditions might due to the adsorption/co-precipitation of chloride ion with the iron oxides. The removal of perchlorate in Fe 0/UV reaction under oxic conditions increased in the presence of methanol (73%, 9h), a radical scavenger, indicating that OH radical can inhibit the removal of perchlorate. The removal of perchlorate by Fe 0-only reaction under oxic condition was highest at neutral pH. Application of the Langmuir-Hinshelwood model indicated that removal of perchlorate was accelerated by adsorption/co-precipitation reactions onto iron oxides and subsequent removal of perchlorate during further oxidation of Fe 0. The results imply that oxic conditions are essential for more efficient removal of perchlorate in Fe 0/H 2O system. © 2011 Elsevier B.V. Source

Lee S.H.,Korea Advanced Institute of Science and Technology | Chung B.H.,Korea Research Institute of Bioscience and Biotechnology | Park T.G.,Korea Advanced Institute of Science and Technology | Nam Y.S.,Korea Advanced Institute of Science and Technology | Mok H.,Konkuk University
Accounts of Chemical Research | Year: 2012

Because of RNA's ability to encode structure and functional information, researchers have fabricated diverse geometric structures from this polymer at the micro- and nanoscale. With their tunable structures, rigidity, and biocompatibility, novel two-dimensional and three-dimensional RNA structures can serve as a fundamental platform for biomedical applications, including engineered tissues, biosensors, and drug delivery vehicles. The discovery of the potential of small-interfering RNA (siRNA) has underscored the applications of RNA-based micro- and nanostructures in medicine.Small-interfering RNA (siRNA), synthetic double-stranded RNA consisting of approximately 21 base pairs, suppresses problematic target genes in a sequence-specific manner via inherent RNA interference (RNAi) processing. As a result, siRNA offers a potential strategy for treatment of many human diseases. However, due to inefficient delivery to cells and off-target effects, the clinical application of therapeutic siRNA has been very challenging. To address these issues, researchers have studied a variety of nanocarrier systems for siRNA delivery.In this Account, we describe several strategies for efficient siRNA delivery and selective gene silencing. We took advantage of facile chemical conjugation and complementary hybridization to design novel siRNA-based micro- and nanostructures. Using chemical crosslinkers and hydrophobic/hydrophilic polymers at the end of siRNA, we produced various RNA-based structures, including siRNA block copolymers, micelles, linear siRNA homopolymers, and microhydrogels. Because of their increased charge density and flexibility compared with conventional siRNA, these micro- and nanostructures can form polyelectrolyte complexes with poorly charged and biocompatible cationic carriers that are both more condensed and more homogenous than the complexes formed in other carrier systems. In addition, the fabricated siRNA-based structures are linked by cleavable disulfide bonds for facile generation of original siRNA in the cytosol and for target-specific gene silencing. These newly developed siRNA-based structures greatly enhance intracellular uptake and gene silencing both in vitro and in vivo, making them promising biomaterials for siRNA therapeutics. © 2012 American Chemical Society. Source

Noh Y.,Konkuk University
Library Hi Tech | Year: 2016

Purpose – The purpose of this paper is to evaluate the current digitization levels of Korean libraries by identifying key elements of library services and measuring them for conventional vs digital approaches and use. Design/methodology/approach – The study utilized previous research related to digital libraries and consultations with experts to arrive at 13 evaluation elements and components within them to analyze. For the purpose of this study specialized libraries, college and university libraries, and public libraries were surveyed, and their responses analyzed to rate their current digitization levels vs more conventional approaches. Findings – First, after determining the elements that characterized the conventional and digital libraries by analyzing different pieces of literature and consulting with experts, 92 factors were identified for each of the conventional and digital elements based on the axis which was composed of 13 items. Second, this study indicated that the libraries obtained one of the conventional or digital characteristics independent of the situation, rather than that the digital library was more effective than the conventional library. Third, in evaluating the chosen libraries used as the examples, it was observed that the libraries had more conventional characteristics among the elements of the digital and conventional libraries. Also, based on the axis used for comparison of 13 items, elements such as the next generation service, the SNS service, and the library program service were more conventional, but elements such as classification and cataloging, acquisition, and the organization were more digitized. Originality/value – This study is the first study in the world to measure the level of digitization of the library. Therefore, hereafter, each library will be able to measure and determine its digital position based on these elements. Up to now, some research was performed in pursuit of extracting the elements of a library but it had relied solely on literature review. Comprehensive research had never been performed as in this study. © 2016, © Emerald Group Publishing Limited. Source

Chung J.-W.,Kongju National University | Chung J.-W.,Konkuk University | Park Y.-J.,Kongju National University
Weed Research | Year: 2010

Summary: This study was conducted to assess the genetic diversity, population structure and linkage disequilibrium (LD) of weedy rice in Korea using 73 weedy rice, 24 landrace lines, 12 breeding lines and 24 international varieties. In total, 772 alleles were detected in 63 microsatellite loci. The number of alleles per marker locus ranged from two to 40, with an average of 12.3. The gene diversity and polymorphism information content value averaged 0.694 and 0.668, with a range of 0.016-0.941 and 0.016-0.946 respectively. In a model-based analysis of population structure, Korean rice germplasm was classified into four subpopulations, designated 'cultivated indica', 'cultivated japonica', 'weedy indica', 'weedy japonica.' Pair-wise estimates of F ST indicated different degrees of differentiation between the four model-based populations, with values ranging from 0.073 (between cultivated and weedy japonica) to 0.474 (between weedy japonica and weedy indica). The weedy indica population appeared to be highly differentiated, compared with the other populations. The cultivated indica lines had the highest gene diversity (0.58), followed by cultivated japonica (0.50), weedy japonica (0.42) and weedy indica (0.35). The total number of private alleles in weedy indica and japonica populations was 39 (23 markers) and 55 (22 markers) respectively. The average of LD (r 2) of weedy indica and japonica types was higher than that of the two cultivated populations, both for inter- and intrachromosome values, indicating the possible reproductive and geographical isolation of sub-populations in cultivated rice fields. © 2010 The Authors. Weed Research © 2010 European Weed Research Society. Source

Ishiwara H.,Konkuk University
Current Applied Physics | Year: 2012

Impurity substitution effects in BiFeO 3 thin films are reviewed from a viewpoint of FeRAM (ferroelectric random access memory) applications, in which such characteristics as a large remanent polarization, a low coercive voltage, and excellent fatigue endurance are most important. First, it is described that substitution experiments for Bi and Fe atoms in the films have already been conducted using almost all rare earth and transition metal elements. A list of the published paper is given in a form of the periodic table of elements. Then, two typical cases, La substitution for the Bi site and Mn substitution for the Fe site, are reviewed in detail. Particular attention is paid to the role of these impurity atoms by which the ferroelectric and insulating properties of BiFeO 3 films are significantly improved. Finally, impurity effects due to substitution or co-substitution of other elements are reviewed. © 2011 Elsevier B.V. All rights reserved. Source

Ishiwara H.,Konkuk University
Journal of Nanoscience and Nanotechnology | Year: 2012

Ferroelectric random access memory (FeRAM) is a nonvolatile memory, in which data are stored using hysteretic P -E (polarization vs. electric field) characteristics in a ferroelectric film. In this review, history and characteristics of FeRAMs are first introduced. It is described that there are two types of FeRAMs, capacitor-type and FET-type, and that only the capacitor-type FeRAM is now commercially available. In chapter 2, properties of ferroelectric films are discussed from a viewpoint of FeRAM application, in which particular attention is paid to those of Pb(Zr,Ti)O3, SrBi 2Ta2O9, and BiFeO3. Then, cell structures and operation principle of the capacitor-type FeRAMs are discussed in chapter 3. It is described that the stacked technology of ferroelectric capacitors and development of new materials with large remanent polarization are important for fabricating high-density memories. Finally, in chapter 4, the optimized gate structure in ferroelectric-gate field-effect transistors is discussed and experimental results showing excellent data retention characteristics are presented. Copyright © 2012 American Scientific Publishers. All rights reserved. Source

Kim S.-J.,Korea University | Hwang I.-S.,Korea University | Na C.W.,Korea University | Kim I.-D.,Korea Advanced Institute of Science and Technology | And 2 more authors.
Journal of Materials Chemistry | Year: 2011

Rh-loaded In2O3 hollow spheres with diameters of ∼2 μm were prepared by a one-pot hydrothermal reaction of aqueous solution containing indium nitrate, rhodium chloride, and glucose and subsequent heat treatment at 500 °C for 2 h. The response to 100 ppm C 2H5OH (Ra/Rg, Ra: resistance in air, Rg: resistance in gas) of 1.67 at% Rh-loaded In2O3 hollow spheres was 4748, which was ∼180 times higher than that of pure In2O3 hollow spheres. Rh loading decreased the temperature for maximum gas response from 475 °C to 371 °C, which also enhanced the selectivity to C2H5OH 15.1-24.7 times and recovery speed. The ultrahigh sensitivity and selectivity to C2H5OH, the lower sensing temperature, and the reduced recovery time were attributed to electronic interactions between Rh and In 2O3 and the promotion of catalytic dissociation of C 2H5OH into reactive gases. © 2011 The Royal Society of Chemistry. Source

Seo M.,Seoul National University | Kim S.K.,Seoul National University | Min Y.-S.,Konkuk University | Hwang C.S.,Seoul National University
Journal of Materials Chemistry | Year: 2011

HfO2 films were grown by atomic layer deposition (ALD) using a new heteroleptic hafnium precursor, tert-butoxytris(ethylmethylamido)hafnium (BTEMAH), and ozone. This BTEMAH precursor achieved a very high growth rate and retained excellent thermal stability in electrical performance due to the high film density of the HfO2 films. Additionally, the structural compatibility between the specific planes of tetragonal HfO2 and rutile TiO2 achieved a high dielectric constant (∼29) for HfO2 films grown on a rutile TiO2 film. It is demonstrated that this BTEMAH is a very promising precursor for the growth of HfO 2 films for both the applications of a gate oxide and a capacitor dielectric. © 2011 The Royal Society of Chemistry. Source

Sonne G.,Gothenburg University | Pena-Aza M.E.,Gothenburg University | Gorelik L.Y.,Chalmers University of Technology | Shekhter R.I.,Gothenburg University | And 3 more authors.
Physical Review Letters | Year: 2010

We consider a nanoelectromechanical Josephson junction, where a suspended nanowire serves as a superconducting weak link, and show that an applied dc bias voltage can result in suppression of the flexural vibrations of the wire. This cooling effect is achieved through the transfer of vibronic energy quanta first to voltage-driven Andreev states and then to extended quasiparticle electronic states. Our analysis, which is performed for a nanowire in the form of a metallic carbon nanotube and in the framework of the density matrix formalism, shows that such self-cooling is possible down to the ground state of the flexural vibration mode of the nanowire. © 2010 The American Physical Society. Source

Nam J.,Inha University | Chippar P.,Inha University | Kim W.,Konkuk University | Ju H.,Inha University
Applied Energy | Year: 2010

The gas crossover phenomenon in polymer electrolyte fuel cells (PEFCs) is an indicator of membrane degradation. The objective of this paper is to numerically investigate the effects of hydrogen and oxygen crossover through the membrane in PEFCs. A gas crossover model is newly developed and implemented in a comprehensive multi-dimensional, multi-phase PEFC model developed earlier. A parametric study is carried out to investigate the effects of the crossover diffusion coefficients for hydrogen and oxygen as well as the membrane thickness. The simulation results demonstrate that the hydrogen crossover induces an additional oxygen reduction reaction (ORR) and consequently causes an additional voltage drop, while the influence of oxygen crossover on PEFC performance is relatively insignificant because it leads to the hydrogen/oxygen chemical reaction at the anode side. Finally, using the time-dependent gas crossover data that are available in the literature (measured in days), we conduct gas crossover simulations to examine the effects of increased gas crossover due to membrane degradation on PEFC performance and successfully demonstrate decaying polarization curves with respect to time. This study clearly elucidates the detailed mechanisms of the hydrogen and oxygen crossover phenomena and their effect on PEFC performance and durability. © 2010 Elsevier Ltd. Source

Kim K.J.,Konkuk University | Kim K.M.,University of Seoul | Kim Y.-W.,University of Seoul
Journal of the European Ceramic Society | Year: 2014

Highly conductive SiC ceramics were fabricated by sintering β-SiC and TiN powder mixture in N2 atmosphere. SiC ceramics exhibited decreased electrical resistivity (ρ) with increasing TiN content. X-ray diffraction data indicated that the specimens consisted of β-SiC grains without a detectible secondary phase for low TiN content (≤2vol%) but contained a Ti2CN phase as the TiN content increased. The temperature-dependent resistivity ρ(T) of specimens revealed semiconductor-like behavior for TiN content up to 10vol% and metal-like behavior above 20vol%. For the specimen with TiN content of 15vol%, ρ(T) remained almost constant (2.06±0.01×10-3Ωcm) in the 4-300K range. The resistivity of metal-like specimens were as low as 3.5×10-4Ωcm for TiN content of 20vol%. For semiconductor-like specimens, ρ(T) was primarily affected by N donors in the β-SiC grains. Metal-like specimens were primarily affected by metallic Ti2CN clusters. © 2013 Elsevier Ltd. Source

BACKGROUND/AIMS: A close relationship has been established between nonalcoholic fatty liver disease (NAFLD) and an elevated risk of coronary heart disease (CHD), but little is known about the association between alcoholic fatty liver disease (AFLD) and CHD risk. The aim of this study was to determine whether AFLD is associated with elevated CHD risk.METHODS: We retrospectively enrolled 10,710 subjects out of 11,469 individuals who visited the Konkuk University Health Care Center for a routine health checkup in 2010. AFLD was diagnosed made when the usual amount of alcohol consumption exceeded 210 g/week in males and 140 g/week in females for the previous 2 years and when hepatic steatosis was detected by liver ultrasonography. The 10-year risk for CHD was estimated using the Framingham Risk Score.RESULTS: Hepatic steatosis was diagnosed in 4,142 of the 10,710 individuals (38.7%); the remainder (i.e., n=6,568) became the control group. The 4,142 individuals with hepatic steatosis were divided into two groups: NAFLD (n=2,953) and AFLD (n=1,189). The risk of CHD was higher in AFLD (6.72±0.12) than in the control group (5.50±0.04, P<0.001), and comparable to that in NAFLD (7.32±0.07, P=0.02).CONCLUSIONS: Individuals with AFLD have an elevated 10-year risk of CHD that is comparable to those with NAFLD. Therefore, AFLD should be considered a significant risk for future CHD, and preventive measures should be considered earlier. Source

Noh K.T.,Korea University | Park Y.-M.,Pusan National University | Cho S.-G.,Konkuk University | Choi E.-J.,Korea University
Experimental Cell Research | Year: 2011

Glycogen synthase kinase-3β (GSK-3β), a multifunctional kinase, is a regulator of lipopolysaccharide (LPS)-mediated septic shock. Apoptosis signal-regulating kinase 1 (ASK1) is also required for LPS-induced activation of p38, which is a crucial determinant for the production of pro-inflammatory cytokines via Toll-like receptor 4 (TLR4) in endotoxemia. Here, we show that attenuation of endotoxemia induced by GSK-3 inhibition is caused by the ASK1 reduction-mediated inhibition of p38, a representative downstream kinase of ASK1. LPS-stimulated activation of p38 was blocked by the reduction of ASK1 via the knockdown of GSK-3β In addition, compared with L929 control cells, ASK1 protein was reduced in L929 cells stably expressing Wnt-3a and in which β-catenin was active, due to the inhibition of GSK-3β activity. GSK-3β inhibition-mediated ASK1 reduction was also confirmed by reduced ASK1 in GSK-3β-deficient mouse embryo fibroblasts (MEFs) and MCF7 GSK-3β siRNA cells. Furthermore, ASK1 protein stability was also attenuated in MCF7 GSK-3β siRNA cells compared with GFP control cells. Consistent with stability data, a much stronger ubiquitination of ASK1 was observed in cells in which GSK-3β was knocked down. These findings suggest that GSK-3β crosstalks with p38 kinase via the regulation of ASK1 protein stability in endotoxemia. © 2011 Elsevier Inc. Source

Background: Food allergies are important etiologic factors in atopic dermatitis. CD19 is a B-cell-specific cell-surface molecule, with a critical role in B-cell activation. Recently, B cells showed independent two subpopulations as CD19hi and CD19low. The allergen-specific responses of the CD19high and CD19low B-cell subpopulations were investigated in patients with non-IgE-mediated food allergy. Methods: Five milk-allergic subjects and eight milk-tolerant subjects were selected by a double-blind placebo-controlled food challenge. Peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with casein or ovalbumin and stained with monoclonal antibodies to distinguish the B-cell subsets. Results: After allergen stimulation, CD19high B cells increased in the number and the fraction in PBMCs in the milk-tolerant group, whereas those remained unchanged in the milk-allergic group. These responses were constant, regardless of the kind of food allergen (milk or egg). The resulting CD19high/CD19low B-cell ratio increased markedly in the milk-tolerant group after allergen stimulation, but was unchanged in the milk-allergic group. IL-10, IL-17, IL-32 and TGF-p-producing regulatory B cells and Foxp3-expressing regulatory B cells were identified predominantly on CD19 low and CD5(+) B cells. Conclusions: The response of the CD19high B-cell subpopulation to allergen stimulation is decisive for immune tolerance of non-IgE-mediated food allergy in atopic dermatitis. CD19 high and CD5(+) B cells dominantly produce cytokines and express Foxp3. Especially, IL-17 and IL-32 expressing B cells (Br17 & Br32) are present. The exact immunological role of CD19 and cytokines including IL-17 and IL-32 around B cells in immune tolerance requires further investigation. © 2012 Bentham Science Publishers. Source

Telke A.A.,Gyeongsang National University | Ghodake G.S.,Kyungpook National University | Kalyani D.C.,Konkuk University | Dhanve R.S.,National Taipei University of Technology | Govindwar S.P.,Shivaji University
Bioresource Technology | Year: 2011

Bacillus sp. ADR secretes an extracellular laccase in nutrient broth, and this enzyme was purified up to 56-fold using acetone precipitation and DEAE-cellulose anion exchange chromatography. The molecular weight of purified laccase was estimated to be 66. kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified laccase oxidized 2,6-dimethoxy phenol, o-tolidine, hydroquinone, l-DOPA and guaiacol. The optimum pH for oxidation of o-tolidine, 2,6-dimethoxy phenol and guaiacol were 3.0, 4.0 and 5.0, respectively. The purified laccase contained 2.7. mol/mol of copper. The laccase was stable up to 40 °C and within the pH range of 7.0-9.0. Well-known inhibitors of multicopper oxidases such as, sodium azide, l-cysteine and dithiothreitol showed significant inhibition of laccase activity. The purified enzyme decolorized structurally different azo dyes with variable decolorization rates and efficiencies of 68-90%. This study is useful for understanding the precise use of Bacillus sp. ADR in the decolorization of textile dyes containing industrial wastewater. © 2010 Elsevier Ltd. Source

Kim B.,Korea University | Chung H.,Konkuk University | Kim W.,Korea University
Nanotechnology | Year: 2012

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were 75Fg 1, 987kWkg 1 and 27Whkg 1, respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (158Fg 1) and energy density (53Whkg 1). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube-and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. © 2012 IOP Publishing Ltd. Source

Ha Y.,South Korean National Institute for Mathematical Sciences | Ho Kim C.,Konkuk University | Ju Lee Y.,Ewha Womans University | Yoon J.,Ewha Womans University
Journal of Computational Physics | Year: 2013

In this paper, we present a new smoothness indicator that evaluates the local smoothness of a function inside of a stencil. The corresponding weighted essentially non-oscillatory (WENO) finite difference scheme can provide the fifth convergence order in smooth regions, especially at critical points where the first derivative vanishes (but the second derivatives are non-zero). We provide a detailed analysis to verify the fifth-order accuracy. Some numerical experiments are presented to demonstrate the performance of the proposed scheme. We see that the proposed WENO scheme provides at least the same or improved behavior over the fifth-order WENO-JS scheme [10] and other fifth-order WENO schemes called as WENO-M [9] and WENO-Z [2], but its advantage seems more salient in two dimensional problems. © 2012 Elsevier Inc. Source

Park K.Y.,Konkuk University | Lee J.W.,Korea University | Song K.G.,Korea Institute of Science and Technology | Ahn K.H.,Korea Institute of Science and Technology
Bioresource Technology | Year: 2011

Potential use of the municipal sludge ozonolysate as a carbon source was examined for phosphorus removal from low strength wastewater in a modified intermittently decanted extended aeration (IDEA) process. At ozone dosage of 0.2g O3/g solids, readily biodegradable COD accounted for about 36% of COD from sludge ozonolysate. The denitrification potential of ozonolysate as a carbon source was comparable to that of acetate. Although, the first order constant for phosphorus release with the ozonolysate was half that of acetate, it was much higher than that of wastewater. Continuous operation of the modified IDEA process showed that the removals of nitrogen and phosphorus were simultaneously enhanced by addition of the ozonolysate. Phosphorus release was significantly induced after complete denitrification indicating that phosphorus release was strongly depended on nitrate concentration. Effectiveness of the ozonolysate as a carbon source for EBPR was also confirmed in a track study of the modified IDEA. © 2010 Elsevier Ltd. Source

Choi W.J.,Konkuk University | Kim H.K.,Hankuk University of foreign Studies
Journal of Health Communication | Year: 2011

This article reviews the landmark studies of advertising claims and analyzes the health claims for food products advertised on Korean TV. The present study examined 1,479 food commercials aired on three major television networks from 2005 to 2007. The commercials containing health claims accounted for 29.5% of the total. The health claims ranged from the nutrient content to the use of ambiguous expressions such as healthy. Among the 5 types of health claims considered, specific nutrient claims ranked first (11.1%), followed by general health claims (9.4%). The regulatory policies of Korea concerning such advertising claims were compared with those of the United States. The results of this study are expected to have important implications for Korean policymakers who need better ways to regulate health claims for food products. Copyright © Taylor & Francis Group, LLC. Source

Sohn K.,Konkuk University
American Journal of Physical Anthropology | Year: 2015

Objectives: Literature on the effect of birth month on height has generally considered regions in temperate climates. However, because many climatic conditions there change with seasons, it is difficult to isolate potential causes. This study estimated the effect of birth month and season on terminal height by analyzing the population of a country with only a few factors driving its climate. Materials and Methods: The sample was derived from nationally representative data of the Indonesian population. We considered 9,262 men and 10,314 women 20-50 years of age. We applied cosinor analysis to a time series of height by birth month. We then applied a more flexible approach by regressing height on a series of dummy variables for birth month (and, subsequently, season) and birth year fixed effects by sex. Results: There was no statistically significant difference in height by birth month. However, although weakly significant, men born in the dry season (June-September) were 2.3 mm shorter than those born in the wet season (the remaining months). The corresponding figure for women was 2.6 mm, a statistically significant difference. Discussion: We eliminated some potential factors previously suggested in the literature, including insolation, the position of our planet with respect to the sun, food availability, and maternal workload. We speculate that babies born in the dry season were affected in the third trimester by the high disease burden that characterizes the wet season. © 2015 Wiley Periodicals, Inc. Source

Matsuno Y.,University of Tokyo | Hur T.,Konkuk University | Fthenakis V.,Columbia University
Resources, Conservation and Recycling | Year: 2012

The demand for cadmium has gradually decreased lately, because of its toxicity and consequent regulations. However, cadmium is coproduced in zinc smelters, and therefore the production of cadmium ingots and cadmium emissions are inevitably affected by zinc demand. Most of the zinc is used for galvanizing steel, and therefore it is of interest to investigate the linkage between cadmium flow and zinc and steel demand. In addition, cadmium is used for secondary batteries, Ni-Cd batteries, alloys, etc. Therefore, a substantial amount of cadmium is still being stocked and discarded in the form of products, and management of the cadmium contained in these end-of-life products is further required in the future. To describe the flow and stock of cadmium in Japan, a dynamic substance flow analysis was conducted in this study. The linkage between cadmium, zinc and steel was quantitatively expressed: 1 t of galvanized steel sheet requires approximately 20 kg zinc, which induces 90 g cadmium in production. The emission intensity of cadmium into air was in the range 0.189-0.296 g Cd/t Zn, whereas the emission intensity into water has decreased by more than 50% during 2003-2008. It is likely that the in-use stock of cadmium and the amount of cadmium contained in discarded products have already passed their peak, and have decreased recently. The recovery rate of cadmium from Ni-Cd batteries has increased. However, it was estimated that 80%, or 700 t, of the cadmium in discarded Ni-Cd batteries, a significant proportion of the total of 840 t of discarded cadmium, had still not been recovered in 2008. The discarded Ni-Cd batteries might have gone into landfill or incineration plants, or been stored away in households. To reduce cadmium emissions, recovery of used Ni-Cd batteries needs to be enhanced. The recovery rate of zinc from end-of-life products to reduce the consumption of zinc ore, which results in the decrease in primary cadmium production, also needs to be enhanced. It is also suggested that the sustainable use of cadmium, e.g., the CdTe photovoltaic systems that use cadmium as a raw material, should be investigated. © 2012 Elsevier B.V. All rights reserved. Source

Song K.-I.,University Technology of MARA | Cho G.-C.,Korea Advanced Institute of Science and Technology | Lee S.-W.,Konkuk University
Probabilistic Engineering Mechanics | Year: 2011

Design parameters commonly used in numerical modeling for tunnel stability analyses tend to be representative (or average) values of global-scale properties. However, the spatial variability of design parameters, such as geotechnical and geological properties, greatly affects the behavior of tunnels during and after construction as well as their long-term responses. Thus, this study presents a simple but robust procedure for stochastic numerical analyses using the finite difference method (FDM) and explores the effects of spatially variable weathered rock properties on various tunnel behaviors, such as deformation, elasticplastic interface, ground reaction curve, and failure mechanism. It was found that the inherent spatial variability of stiffness and strength parameters affects the deformation behavior of tunnels and even changes its failure mechanism: Elastic modulus for the MohrCoulomb model and geological strength index (GSI) for the HoekBrown model play a key role in deformation characteristics. Considering the wide range of spatial variability in in-situ deposits, the accurate estimation of elastic modulus and GSI is very important. The spatial variability of the ground can affect the ground reaction behavior and can bring on an unfavorable ground reaction curve (GRC). It can cause an increase in the tunnel support pressure, and can induce a larger displacement than the homogeneous case. The shear failure mechanism of the tunnel can be significantly affected by a large relative correlation length. It is suggested that we should estimate and consider the variability of rock properties accurately as part of a routine tunnel design framework. © 2010 Elsevier Ltd. All rights reserved. Source

Kwon O.I.,Konkuk University | Jeong W.C.,Kyung Hee University | Sajib S.Z.K.,Kyung Hee University | Kim H.J.,Kyung Hee University | Woo E.J.,Kyung Hee University
Physics in Medicine and Biology | Year: 2014

Magnetic resonance electrical impedance tomography (MREIT) is an emerging method to visualize electrical conductivity and/or current density images at low frequencies (below 1 KHz). Injecting currents into an imaging object, one component of the induced magnetic flux density is acquired using an MRI scanner for isotropic conductivity image reconstructions. Diffusion tensor MRI (DT-MRI) measures the intrinsic three-dimensional diffusion property of water molecules within a tissue. It characterizes the anisotropic water transport by the effective diffusion tensor. Combining the DT-MRI and MREIT techniques, we propose a novel direct method for absolute conductivity tensor image reconstructions based on a linear relationship between the water diffusion tensor and the electrical conductivity tensor. We first recover the projected current density, which is the best approximation of the internal current density one can obtain from the measured single component of the induced magnetic flux density. This enables us to estimate a scale factor between the diffusion tensor and the conductivity tensor. Combining these values at all pixels with the acquired diffusion tensor map, we can quantitatively recover the anisotropic conductivity tensor map. From numerical simulations and experimental verifications using a biological tissue phantom, we found that the new method overcomes the limitations of each method and successfully reconstructs both the direction and magnitude of the conductivity tensor for both the anisotropic and isotropic regions. © 2014 Institute of Physics and Engineering in Medicine. Source

Kim K.J.,Konkuk University | Lim K.-Y.,University of Seoul | Kim Y.-W.,University of Seoul
Journal of the American Ceramic Society | Year: 2014

The electrical and thermal properties of SiC ceramics containing 1 vol% nitrides (BN, AlN or TiN) were investigated with 2 vol% Y2O3 addition as a sintering additive. The AlN-added SiC specimen exhibited an electrical resistivity (3.8 × 101 Ω·cm) that is larger by a factor of ~102 compared to that (1.3 × 10-1 Ω·cm) of a baseline specimen sintered with Y2O3 only. On the other hand, BN- or TiN-added SiC specimens exhibited resistivity that is lower than that of the baseline specimen by a factor of 10-1. The addition of 1 vol% BN or AlN led to a decrease in the thermal conductivity of SiC from 178 W/m·K (baseline) to 99 W/m·K or 133 W/m·K, respectively. The electrical resistivity and thermal conductivity of the TiN-added SiC specimen were 1.6 × 10-2 Ω·cm and 211 W/m·K at room temperature, respectively. The present results suggest that the electrical and thermal properties of SiC ceramics are controllable by adding a small amount of nitrides. © 2014 The American Ceramic Society. Source

Cheung K.,National Tsing Hua University | Cheung K.,Konkuk University | Yuan T.-C.,Academia Sinica, Taiwan
Physical Review Letters | Year: 2012

Current Higgs boson searches in various channels at the LHC point to an excess at around 124-126 GeV due to a possibly standard-model-like Higgs boson. If one examines more closely the channels (γγ, WW *, and ZZ *) that have excess, this "Higgs boson" may be the Randall-Sundrum radion ·. Because of the trace anomaly, the radion has stronger couplings to the photon and gluon pairs. Thus, it will enhance the production rates into gg and γγ, while those for WW *, ZZ *, and bb̄ are reduced relative to their standard model values. We show that it can match well with the data from CMS for m ·=124GeV, and the required scale Λ ·∼· is about 0.68 TeV. © 2012 American Physical Society. Source

Lee K.-S.,Konkuk University
IEEE Transactions on Biomedical Engineering | Year: 2010

It is well-known that a clear relationship exists between human voices and myoelectric signals (MESs) from the area of the speakers mouth. In this study, we utilized this information to implement a speech synthesis scheme in which MES alone was used to predict the parameters characterizing the vocal-tract transfer function of specific speech signals. Several feature parameters derived from MES were investigated to find the optimal feature for maximization of the mutual information between the acoustic and the MES features. After the optimal feature was determined, an estimation rule for the acoustic parameters was proposed, based on a minimum mean square error (MMSE) criterion. In a preliminary study, 60 isolated words were used for both objective and subjective evaluations. The results showed that the average Euclidean distance between the original and predicted acoustic parameters was reduced by about 30% compared with the average Euclidean distance of the original parameters. The intelligibility of the synthesized speech signals using the predicted features was also evaluated. A word-level identification ratio of 65.5% and a syllable-level identification ratio of 73% were obtained through a listening test. © 2006 IEEE. Source

Kwon S.J.,Konkuk University | Bard A.J.,University of Texas at Austin
Journal of the American Chemical Society | Year: 2012

This study demonstrates a highly sensitive sensing scheme for the detection of low concentrations of DNA, in principle down to the single biomolecule level. The previously developed technique of electrochemical current amplification for detection of single nanoparticle (NP) collisions at an ultramicroelectrode (UME) has been employed to determine DNA. The Pt NP/Au UME/hydrazine oxidation reaction was employed, and individual NP collision events were monitored. The Pt NP was modified with a 20-base oligonucleotide with a C6 spacer thiol (detection probe), and the Au UME was modified with a 16-base oligonucleotide with a C6 spacer thiol (capture probe). The presence of a target oligonucleotide (31 base) that hybridized with both capture and detection probes brought a Pt NP on the electrode surface, where the resulting electrochemical oxidation of hydrazine resulted in a current response. © 2012 American Chemical Society. Source

Baek S.-H.,Seoul National University | Kim S.,Seoul National University | Lee K.,Seoul National University | Lee J.-K.,Konkuk University | Hahn J.-S.,Seoul National University
Enzyme and Microbial Technology | Year: 2012

As an effort to find suitable endoglucanases to generate cellulolytic yeast strains, two fungal endoglucanases, Thermoascus aurantiacus EGI and Trichoderma reesei EGII, and two bacterial endoglucanases, Clostridium thermocellum CelA and CelD, were expressed on the yeast surface, and their surface expression levels, pH- and temperature-dependent enzyme activities, and substrate specificities were analyzed. T. aurantiacus EGI showed similar patterns of pH- and temperature-dependent activities to those of T. reesei EGII which has been widely used due to its high enzyme activity. Although EGII showed higher carboxymethyl cellulose (CMC) degradation activity than EGI, EGI showed better activity toward phosphoric acid swollen cellulose (PASC). For ethanol production from PASC, we combined three types of yeast cells, each displaying T. aurantiacus EGI, T. reesei CBHII (exoglucanase) and Aspergillus aculeatus BGLI (β-glucosidase), instead of co-expressing these enzymes in a single cell. In this system, ethanol production can be easily optimized by adjusting the combination ratio of each cell type. A mixture of cells with the optimized EGI:CBHII:BGLI ratio of 6:2:1 produced 1.3 fold more ethanol (2.1. g/l) than cells composed of an equal amount of each cell type, suggesting the usefulness of this system for cellulosic ethanol production. © 2012 Elsevier Inc. Source

Choi N.,Konkuk University | Ko E.S.,Korea Cancer Center Hospital
Korean Journal of Radiology | Year: 2010

Mammary hamartomas are typically a benign condition and rarely develop into malignant lesions. Only 14 cases of carcinomas associated with a hamartoma have been documented in the literature. In this case report, we describe a case of invasive ductal carcinoma within a hamartoma in a 72-year-old woman. Mammography, ultrasonography, and magnetic resonance imaging showed the features of a typical hamartoma with a suspicious mass arising in it. This case illustrates the importance of identification of unusual findings in a typical mammary hamartoma on radiologic examinations. Source

Chung C.,Konkuk University | Raingo J.,CONICET
Journal of Neurochemistry | Year: 2013

Central synapses operate neurotransmission in several modes: synchronous/fast neurotransmission (neurotransmitters release is tightly coupled to action potentials and fast), asynchronous neurotransmission (neurotransmitter release is slower and longer lasting), and spontaneous neurotransmission (where small amounts of neurotransmitter are released without being evoked by an action potential). A substantial body of evidence from the past two decades suggests that seemingly identical synaptic vesicles possess distinct propensities to fuse, thus selectively serving different modes of neurotransmission. In efforts to better understand the mechanism(s) underlying the different modes of synaptic transmission, many research groups found that synaptic vesicles used in different modes of neurotransmission differ by a number of synaptic proteins. Synchronous transmission with higher temporal fidelity to stimulation seems to require synaptotagmin 1 and complexin for its Ca2+ sensitivity, RIM proteins for closer location of synaptic vesicles (SV) to the voltage operated calcium channels (VGCC), and dynamin for SV retrieval. Asynchronous release does not seem to require functional synaptotagmin 1 as a calcium sensor or complexins, but the activity of dynamin is indispensible for its maintenance. On the other hand, the control of spontaneous neurotransmission remains less clear as deleting a number of essential synaptic proteins does not abolish this type of synaptic vesicle fusion. VGCC distance from the SV seems to have little control on spontaneous transmission, while there is an involvement of functional synaptic proteins including synaptotagmins and complexin. Recently, presynaptic deficits have been proposed to contribute to a number of pathological conditions including cognitive and mental disorders. In this review, we evaluate recent advances in understanding the regulatory mechanisms of synaptic vesicle dynamics and in understanding how different molecular substrates maintain selective modes of neurotransmission. We also highlight the implications of these studies in understanding pathological conditions. © 2013 International Society for Neurochemistry. Source

Kim H.-S.,Konkuk University
Structural Design of Tall and Special Buildings | Year: 2015

Summary Differential column shortening should be reduced to mitigate the adverse effects caused by such shortening in a tall building. The axial stiffness of columns with greater shortening than adjacent columns should be increased to reduce the differential column shortening. The axial stiffness of the columns can be effectively increased by utilizing additional reinforcement for them. The optimum distributions of this additional reinforcement to reduce the differential column shortening in a tall building are determined. An optimization problem is formulated to minimize the total amount of reinforcement. Three analysis models, namely a fixed-section, fixed-stress and general model, are presented as numerical examples. The contour plots for a two-variable problem of the three analysis models are presented. The generalized reduced gradient method is applied to obtain the optimum solutions of multi-variable problems. The differential column shortenings after optimization confirm that the optimization program developed in this study can yield the optimum distributions of additional reinforcement. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd. Source

Lee W.H.,Konkuk University | Choi H.H.,Pohang University of Science and Technology | Kim D.H.,Soongsil University | Cho K.,Pohang University of Science and Technology
Advanced Materials | Year: 2014

Recent studies of the bias-stress-driven electrical instability of organic field-effect transistors (OFETs) are reviewed. OFETs are operated under continuous gate and source/drain biases and these bias stresses degrade device performance. The principles underlying this bias instability are discussed, particularly the mechanisms of charge trapping. There are three main charge-trapping sites: the semiconductor, the dielectric, and the semiconductor-dielectric interface. The charge-trapping phenomena in these three regions are analyzed with special attention to the microstructural dependence of bias instability. Finally, possibilities for future research in this field are presented. This critical review aims to enhance our insight into bias-stress-induced charge trapping in OFETs with the aim of minimizing operational instability. Recent studies of the bias-stress-driven electrical instability of organic field-effect transistors (OFETs) are reviewed. The principles underlying this bias instability are discussed, particularly the mechanisms of charge trapping. The charge-trapping phenomena in the semiconductor, the dielectric, and the semiconductor-dielectric interface are analyzed with special attention to the microstructural dependence of bias instability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Kim H.J.,Jeju National University | Paik H.-D.,Konkuk University
JAOCS, Journal of the American Oil Chemists' Society | Year: 2014

The impacts of four different types of tocotrienol homologues on the singlet oxygen oxidation of lard were evaluated by measuring the headspace oxygen content and the peroxide value. Singlet oxygen oxidation of lard was induced by chlorophyll photosensitization. Samples of 0.100, 0.250, and 0.400 M lard in methylene chloride containing chlorophyll and α-, β-, γ-, or δ-tocotrienol were prepared and stored under light at 3,000 lux for 4 h. All tocotrienol homologues at 1.20 mM significantly prevented the singlet oxygen oxidation of lard. Chlorophyll under light produced singlet oxygen at 1.09 μmol oxygen/mL headspace/h. A steady state kinetic study showed that tocotrienols reduced the singlet oxygen oxidation of lard by quenching the singlet oxygen. Singlet oxygen reacted with lard at 6.50 × 104 M-1 s-1. α-, β-, γ-, and δ-tocotrienol quenched singlet oxygen with the rate of 2.16, 1.99, 2.05, and 0.800 × 107 M-1 s-1, respectively. Among them, α-tocotrienol significantly prevented singlet oxygen oxidation of lard. © 2013 AOCS. Source

Graham D.Y.,Baylor College of Medicine | Lee S.-Y.,Konkuk University
Gastroenterology Clinics of North America | Year: 2015

Bismuth triple therapy was the first effective Helicobacter pylori eradication therapy. The addition of a proton pump inhibitor helped overcome metronidazole resistance. Its primary indication is penicillin allergy or when clarithromycin and metronidazole resistance are both common. Resistance to the primary first-line therapy have centered on complexity and difficulties with compliance. Understanding regional differences in effectiveness remains unexplained because of the lack of studies including susceptibility testing and adherence data. We discuss regimen variations including substitutions of doxycycline, amoxicillin, and twice a day therapy and provide suggestions regarding what is needed to rationally and effectively use bismuth quadruple therapy. © 2015. Source

Kim K.O.,Konkuk University | Zuo M.J.,University of Alberta
IIE Transactions (Institute of Industrial Engineers) | Year: 2015

During the early stages of system development, various factors are considered when determining an allocation weight to apportion a systems reliability requirement to each subsystem. Previous methods have included subsystem mission time as a factor in obtaining the allocation weight in order to allocate a higher failure rate to a subsystem with a shorter mission time than the systems mission time. This article, first shows that the results obtained from previous methods are misleading, mainly because the allocated failure rate of the subsystem is expressed in the systems mission time rather than the subsystems mission time. It is further shown that if a designer intends to allocate a lower failure rate to a subsystem that has to operate longer in the system, subsystem mission time must not be included as a factor when determining the allocation weight. If a designer wants to allocate the system failure rate equally to each subsystem regardless of a subsystems mission time, subsystem mission time must be included as a factor. © 2015 © "IIE". Source

Chong Y.,Konkuk University | Choo H.,Korea Institute of Science and Technology
Expert Opinion on Investigational Drugs | Year: 2010

Importance of the field: The main therapeutic area of 5-HT3 receptor antagonists is the treatment of chemotherapy-induced nausea and vomiting (CINV), which is the most common and distressing side effects of anticancer treatment. The second major clinical application of 5-HT3 receptor antagonists is in the treatment of irritable bowel syndrome (IBS). 5-HT3 antagonists have been widely used and found to decrease gut transit, increase fluid absorption and reduce pain. The uses of 5-HT3 antagonists are expending to treatment of CNS diseases such as anxiety and sleep disorders as antipsychotics and so on. Areas covered in this review: The structures, in vitro activities, in vivo effects and some clinical data on 5-HT3 receptor antagonists under development. What the reader will gain: Future research directions in 5-HT3 antagonists based on the clinical trial data of the pipeline molecules. Take home message: Most drug candidates in clinical trials were discovered in the early 1990s and their patent expiry is imminent. Acquiring intellectual properties of novel 5-HT 3 receptor antagonists with improved efficacies would provide a bright future. Particularly, as the current 5-HT3 receptor antagonists are classified into only three representative structural families (one third are zacopride-like benzamides and the others are ondansteron-like tricyclic compounds and dolansetron-like bicyclic compounds), structurally diverse compound libraries need to be extensively investigated for identification of novel 5-HT3 receptor antagonists. © 2010 Informa UK, Ltd. Source

New 2013 guidelines on Helicobacter pylori (H. pylori) infection have been published in China, Japan, and South Korea. Like the previous ones, these new guidelines differ between the three countries with regard to the indications for H. pylori eradication, diagnostic methods, and treatment regimens. The most profound change among all of the guidelines is that the Japanese national health insurance system now covers the expenses for all infected subjects up to second-line treatment. This makes the Japanese indications for eradication much wider than those in China and South Korea. With regard to the diagnosis, a serum H. pylori antibody test is not recommended in China, whereas it is considered to be the most reliable method in Japan. A decrease relative to the initial antibody titer of more than 50% after 6-12 mo is considered to be the most accurate method for determining successful eradication in Japan. In contrast, only the urea breath test is recommended after eradication in China, while either noninvasive or invasive methods (except the bacterial culture) are recommended in South Korea. Due to the increased rate of antibiotics resistance, first-line treatment is omitted in China and South Korea in cases of clarithromycin resistance. Notably, the Japanese regimen consists of a lower dose of antibiotics for a shorter duration (7 d) than in the other countries. There is neither 14 d nor bismuth-based regimen in the first-line and second-line treatment in Japan. Such differences among countries might be due to differences in the approvals granted by the governments and national health insurance system in each country. Further studies are required to achieve the best results in the diagnosis and treatment of H. pylori infection based on cost-effectiveness in East Asian countries. © 2014 Baishideng Publishing Group Co., Limited. All rights reserved. Source

You J.S.,Konkuk University | Han J.H.,Sungkyunkwan University
Archives of Pharmacal Research | Year: 2014

The diverse epigenetic modifications regulate the gene expression and determine the cellular identity. Pioneering work over the past decades has highlighted that these epigenetic regulations establish normal development but also contribute various diseases. Furthermore, the epigenetic priming events are considered as a key factor for efficient master transcription factor(s) mediated reprogramming process. With the advent of numerous small molecules that target specific enzymes or proteins involved in the epigenetic regulation of gene expression, the utilization of epigenetic targets is emerging as a valuable approach to cancer therapy and cellular reprogramming. Here, we briefly present the basic principles of epigenetic regulations and review the recent application of epigenetic targeting small molecules. © 2014 The Pharmaceutical Society of Korea. Source

Lim H.,Ewha Womans University | Yim C.,Konkuk University | Swartzlander Jr. E.E.,University of Texas at Austin
IEEE Transactions on Computers | Year: 2010

High-speed IP address lookup is essential to achieve wire speed packet forwarding in Internet routers. The longest prefix matching for IP address lookup is more complex than exact matching because it involves dual dimensions: length and value. This paper presents a new formulation for IP address lookup problem using range representation of prefixes and proposes an efficient binary trie structure named a priority trie. In this range representation, prefixes are represented as ranges on a number line between 0 and 1 without expanding to the maximum length. The best match to a given input address is the smallest range that includes the input. The priority trie is based on the trie structure, with empty internal nodes in the trie replaced by the priority prefix which is the longest among those in the subtrie rooted by the empty nodes. The search ends when an input matches a priority prefix, which significantly improves the search performance. Performance evaluation using real routing data shows that the proposed priority trie is very good in performance metrics such as lookup speed, memory size, update performance, and scalability. © 2006 IEEE. Source

Chen X.-B.,Konkuk University
Journal of the Korean Physical Society | Year: 2011

We have studied the polarized Raman scattering of VO2 thin film in the low-temperature monoclinic insulating phase. We found that the Raman spectra showed distinctly different characters between the parallel and the cross configurations with respect to the (010) surface of the VO2 thin film. These distinctly different characters enabled us to make a relatively direct assignment of the observed Raman modes. Our results first suggested all nine Ag and nine Bg Raman active modes that are predicted by group theory. We also compared our assignment of the Raman modes with those in earlier reported studies; our discussion indicates that our assignment more precisely presents the symmetries of the observed Raman modes. Source

Subramanian A.,Konkuk University | Wang H.-W.,Chung Yuan Christian University
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2014

A hierarchal multilayer-structured photoelectrode was prepared and the performance of dye-sensitized solar cell was compared with the standard P25 electrodes in different thickness and bilayer-structured TiO2 electrode. Scanning electron microscope and X-ray diffraction patterns were used to analyze the morphology and crystal phases of these electrodes. The multilayer-structured photoelectrode showed a superior performance compared to those of the other three electrodes. The enhancement was attributed to higher amount of dye adsorption, large incident photon-to-current conversion yield due to greater fraction of light scattering and the good charge transportation because of the optimized structure of the TiO2 electrode. The UV-vis measurement confirmed the higher dye loading capacity of the multilayered-structure. Electrochemical spectra (EIS) were used to analyze the charge transport kinetic in these electrodes. The EIS analysis showed large electron injection rate, the suppression of recombination rate and longer electron lifetime in the multilayer-structured photoelectrode due to the optimized structure. The incident photon-to-current conversion efficiency measurement revealed the greater light harvesting efficiency of the multilayer-structured photo-electrode. Source

Lim Y.-T.,Konkuk University | Chow J.W.,Center for Neuroscience and Neurological Recovery | Chae W.-S.,Kyungpook National University
Sports Biomechanics | Year: 2012

This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads. © 2012 Copyright Taylor and Francis Group, LLC. Source

Jung K.Y.,Kongju National University | Kang Y.C.,Konkuk University
Physica B: Condensed Matter | Year: 2010

Ce-doped yttrium aluminum garnet (YAG:Ce) particles were prepared by microwave heating and conventional precipitation methods. The YAG:Ce particles prepared by microwave synthesis showed higher luminescence intensity compared with those prepared by the precipitation method. The emission intensity of YAG:Ce particles had a linear relation to the crystallite size, regardless of the preparation method. According to the XRD analysis, the YAG particles prepared by the microwave method had larger crystallite size than that of the particles prepared by the precipitation method. In addition, the pure YAG phase without any impurity was obtained by the microwave method, even at low thermal-treatment temperature. Thus, it was concluded that the high crystallinity and phase purity are responsible for the high luminescence intensity of microwave-synthesized YAG:Ce phosphor. © 2009 Elsevier B.V. All rights reserved. Source

Stomph T.J.,Wageningen University | Choi E.Y.,Flinders University | Choi E.Y.,Konkuk University | Stangoulis J.C.R.,Flinders University
Annals of Botany | Year: 2011

Background and Aims Enhancing the zinc (Zn) concentration in wheat (Triticum aestivum) grain is a breeding objective in order to improve human Zn nutrition. At enhanced plant Zn uptake, grain Zn levels do not increase proportionally and within the grain the endosperm Zn levels remain below grain Zn levels. This study analysed the temporal dynamics of Zn concentrations in grain tissues during grain filling to find major bottlenecks. Methods Plants of two cultivars were grown at 1 and 5 mg Zn kg-1 soil. Individual panicles were harvested 7, 14, 24 or 34 d after their flowering or at maturity and seeds were dissected into constituting tissues, which were analysed for Zn and other minerals. Key Results The Zn concentration of the crease was found to increase five-to nine-fold between 7 and 34 d after anthesis, while that of the endosperm decreased by 7 and 45 when grown at 1 or 5 mg Zn kg-1, respectively. The Zn turnover rate (d-1) in the crease tissues was either independent of the Zn application level or higher at the lower Zn application level, and the Zn concentration increased in the crease tissues with time during grain filling while the turnover rate gradually decreased. Conclusions There is significant within-seed control over Zn entering the seed endosperm. While the seed crease Zn concentration can be raised to very high levels by increasing external Zn supply, the endosperm Zn concentrations will not increase correspondingly. The limited transfer of Zn beyond the crease requires more research to provide further insight into the rate-determining processes and their location along the pathway from crease to the deeper endosperm. © 2011 The Author. Source

Park K.-M.,Konkuk University | Park K.-M.,University of Pennsylvania | Kim Y.-H.,University of Ulsan | Marchlinski F.E.,University of Pennsylvania
PACE - Pacing and Clinical Electrophysiology | Year: 2012

The surface electrocardiogram (ECG) is a useful tool to help identify the sites of origin of ventricular tachycardia (VT). Despite such limitations as chest wall deformity and metabolic and drug effects, the analysis of the QRS morphologic patterns and vectors can discern the site of activation of myocardium. There have been described numerous reports about ECG features of idiopathic left-and right-ventricular VT. In this review, we summarized typical ECG characteristics according to the VT sites of origin based on previous reports, with anatomical considerations of the left and right ventricles, including the outflow tracts and epicardium. (PACE 2012;35:1516-1527) ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc. Source

An J.H.,Konkuk University | Oh B.-K.,Sogang University | Choi J.W.,Sogang University
Journal of Biomedical Nanotechnology | Year: 2013

Tyrosine hydroxylase, the rate-limiting enzyme of catecholamine biosysthesis, is predominantly expressed in several cell groups within the brain, including the dopaminergic neurons of the substantia nigra and ventral tegmental area. We evaluated the efficacy of this protein-detection method in detecting tyrosine hydroxylase in normal and oxidative stress damaged dopaminergic cells. In this study, a coupling of DNA barcode and bead-based immnunoassay for detecting tyrosine hydroxylaser with PCR-like sensitivity is reported. The method relies on magnetic nanoparticles with antibodies and nanoparticles that are encoded with DNA and antibodies that can sandwich the target protein captured by the nanoparticle-bound antibodies. The aggregate sandwich structures are magnetically separated from solution, and treated to remove the conjugated barcode DNA. The DNA barcodes were identified by PCR analysis. The concentration of tyrosine hydroxylase in dopaminergic cell can be easily and rapidly detected using bio-barcode assay. The bio-barcode assay is a rapid and high-throughput screening tool to detect of neurotransmitter such as dopamine. Copyright © 2013 American Scientific Publishers All rights reserved. Source

Yu M.S.,Konkuk University | Jang Y.J.,University of Ulsan
Aesthetic Surgery Journal | Year: 2014

Background: Preoperative computer simulation (PCS) is a tool for demonstrating potential rhinoplasty results to patients and determining the patient's preferred external nasal appearance. Objectives: The authors evaluated the effectiveness of PCS in Asian rhinoplasty patients. Methods: The records of 224 patients who underwent rhinoplasty were reviewed. Sixty-eight (30.4%) of these patients had received PCS. To evaluate the accuracy of PCS in predicting postoperative results, postoperative photographs and PCS images were graded on a 4-point scale by a panel of 3 otolaryngologists. Postoperative patient satisfaction was compared between the PCS and non-PCS groups. Aesthetic parameters were assessed in the PCS images to determine the patient's preferred external nasal appearance. Results: The mean overall accuracy of PCS was 86.0% according to the otolaryngologist panel's ratings: 41.2% of the surgical results were rated as identical, 44.1% as similar, 13.2% as approximate, and 1.5% as poor. There were no significant differences between the PCS and non-PCS groups in terms of patient satisfaction or revision rates (P > .05). The most favored nasal appearances were straight dorsum (63.2%), straight columella (50.0%), and convergent alar axis (64.7%). The mean (± standard deviation) preferred nasofrontal and nasolabial angles were 137.5° ± 6.9° and 97.3° ± 8.6°, respectively. Conclusions: Preoperative computer simulation is an accurate tool for assessing preferred external nasal appearance and can be a reliable predictor of postoperative rhinoplasty results in Asian patients. © 2014 The American Society for Aesthetic Plastic Surgery, Inc. Source

Kim J.,Konkuk University
Analog Integrated Circuits and Signal Processing | Year: 2013

Equation-based circuit optimization using geometric programming (GP) is a promising analog and mixed-signal design framework that is inherently capable of hierarchical design synthesis. By taking a dynamic comparator as a test vehicle, this paper presents a reduced-complexity cell-level macromodeling method compatible with equation-based circuit optimization using GP. A key contribution of this paper is the demonstration of the complexity-reduction method in creating a convex, empirical, and cell-level macromodel. The variable space reduction is guided by the 1st-order modeling obtained from fundamental understandings on the circuit behavior. The proposed modeling is ideally applicable to create a macromodel exhibiting nonlinear behaviors in time-domain, which are not readily captured in a traditional equation-based modeling approach. The numerical experiment using a dynamic comparator in 0.13 μm CMOS process as a test vehicle indicates that the modeling errors for major performance metrics are less than 5 %, while obtained Pareto-front tradeoff provides useful design guidelines on the architecture-level design exploration. © 2013 Springer Science+Business Media New York. Source

Kim S.,Korea University | Lee J.-H.,Sungkyunkwan University | Lee J.,Ewha Womans University | Kim S.-W.,Sungkyunkwan University | And 5 more authors.
Journal of the American Chemical Society | Year: 2013

We report the synthesis of KNbO3 nanowires (NWs) with a monoclinic phase, a phase not observed in bulk KNbO3 materials. The monoclinic NWs can be synthesized via a hydrothermal method using metallic Nb as a precursor. The NWs are metastable, and thermal treatment at ∼450 C changed the monoclinic phase into the orthorhombic phase, which is the most stable phase of KNbO3 at room temperature. Furthermore, we fabricated energy-harvesting nanogenerators by vertically aligning the NWs on SrTiO 3 substrates. The monoclinic NWs showed significantly better energy conversion characteristics than orthorhombic NWs. Moreover, the frequency-doubling efficiency of the monoclinic NWs was ∼3 times higher than that of orthorhombic NWs. This work may contribute to the synthesis of materials with new crystalline structures and hence improve the properties of the materials for various applications. © 2012 American Chemical Society. Source

Lim J.-H.,Dana-Farber Cancer Institute | Lim J.-H.,Harvard University | Lim J.-H.,Konkuk University | Luo C.,Dana-Farber Cancer Institute | And 5 more authors.
Cancer Research | Year: 2014

Metabolic targets offer attractive opportunities for cancer therapy. However, their targeting may activate alternative metabolic pathways that can still support tumor growth. A subset of human melanomas relies on PGC1a-dependent mitochondrial oxidative metabolism to maintain growth and survival. Herein, we showthat loss of viability caused by suppression of PGC1a in these melanomas is rescued by induction of glycolysis. Suppression of PGC1a elevates reactive oxygen species levels decreasing hypoxia-inducible factor-1a (HIF1a) hydroxylation that, in turn, increases its protein stability. HIF1a reprograms melanomas to become highly glycolytic and dependent on this pathway for survival. Dual suppression of PGC1a and HIF1a causes energetic deficits and loss of viability that are partially compensated by glutamine utilization. Notably, triple suppression of PGC1a, HIF1a, and glutamine utilization results in complete blockage of tumor growth. These results show that due to high metabolic and bioenergetic flexibility, complete treatment of melanomas will require combinatorial therapy that targets multiple metabolic components. © 2014 AACR. Source

Kim Y.C.,Seoul National University | Lee S.C.,Seoul National University | Kim J.H.,Konkuk University
Anesthesia and Analgesia | Year: 2013

BACKGROUND: Transforaminal epidural steroid injection (TFESI) is a useful treatment modality for pain management. Most complications of TFESI are minor and transient. However, there is a risk of serious complications such as nerve injury, spinal cord infarct, or paraplegia. Some of the risks are related to direct injury to the vessel or intravascular injection of the particulate steroid. We prospectively tested the hypothesis that the intravascular injection rate of the Whitacre needle is lower than that of the Quincke needle during TFESI. METHODS: This study was a randomized trial of 1376 TFESIs at the S1 level. We collected data of age, gender, height, weight, laterality (right/left), history of lumbosacral spine operation, history of appropriate interval discontinuation of anticoagulation medicines, and underlying disease. During the S1 TFESI, intrasacral bone contact, a blood aspiration test, and real-time fluoroscopy of the intravascular injection using contrast media were investigated. RESULTS: There were no significant differences in the intravascular injection rate with respect to age, gender, height, weight, hypertension, diabetes mellitus, laterality, history of lumbosacral spine operation, or history of appropriate interval discontinuation of anticoagulation medicines. Intravascular injection was significantly associated with a blood aspiration test (P < 0.001), needle tip type (P = 0.002), intrasacral bone contact (P < 0.001), and physicians (some P < 0.05). The use of Quincke needles and intrasacral bone contact increased the rate of intravascular injection. CONCLUSIONS: To reduce the risk of intravascular injection, the use of Whitacre needles without intrasacral bone contact may be a safer and more effective approach. Copyright © 2013 International Anesthesia Research Society. Source

Cho Y.M.,Konkuk University | Cho Y.M.,Seoul National University
International Journal of Modern Physics A | Year: 2014

We demonstrate the monopole condensation in SU(3) QCD. We first discuss the gauge independent and Weyl symmetric Abelian (Cho-Duan-Ge) decomposition of the SU(3) QCD, and present a new gauge invariant integral expression of the one-loop effective action which has no infrared divergence. Integrating it gauge invariantly imposing the color reflection invariance ("the C-projection") we show that the effective potential generates the stable monopole condensation which generates the mass gap. © 2014 World Scientific Publishing Company. Source

Cundy N.,Seoul National University | Cho Y.M.,Konkuk University | Cho Y.M.,Seoul National University | Lee W.,Seoul National University | Leem J.,Seoul National University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We investigate the relationship between colour confinement and topological structures derived from the gauge invariant Abelian (Cho-Duan-Ge) decomposition. This Abelian decomposition is made imposing an isometry on a colour field n which selects the Abelian direction; the principle novelty of our study is that we have defined this field in terms of the eigenvectors of the Wilson loop. This allows us to establish an equivalence between the path ordered integral of the non-Abelian gauge fields with an integral over an Abelian restricted gauge field which is tractable both theoretically and numerically in lattice QCD. By using Stokes' theorem, we can relate the Wilson loop in terms of a surface integral over a restricted field strength, and show that the restricted field strength may be dominated by topological structures, which occur when one of the parameters parametrising the colour field n winds itself around a non-analyticity in the colour field. If they exist, these objects will lead to an area law scaling for the Wilson loop and provide a mechanism for quark confinement. We search for these structures in quenched lattice QCD. We perform the Abelian decomposition, and find that the restricted field strength is dominated by peaks on the lattice. Wilson loops containing these peaks show a stronger area-Law and thus provide the dominant contribution to the string tension. © 2014 The Authors. Source

Paeng S.-H.,Konkuk University
General Relativity and Gravitation | Year: 2011

We obtain the volume comparison between spacelike hypersurfaces in a Lorentzian manifold with integral Ricci and mean curvature bounds. Also we extend volume comparisons to weighted volume comparisons with integral norms of the generalized Ricci tensor. © 2010 Springer Science+Business Media, LLC. Source

Shim Y.-H.,Konkuk University | Paik Y.-K.,Yonsei University
Proteomics | Year: 2010

Caenorhabditis elegans, a free-living soil nematode, is an ideal model system for studying various physiological problems relevant to human diseases. Despite its short history, C. elegans proteomics is receiving great attention in multiple research areas, including the genome annotation, major signaling pathways (e.g. TGF-b and insulin/IGF-1 signaling), verification of RNA interference-mediated gene targeting, aging, disease models, as well as peptidomic analysis of neuropeptides involved in behavior and locomotion. For example, a proteome-wide profiling of developmental and aging processes not only provides basic information necessary for constructing a molecular network, but also identifies important target proteins for chemical modulation. Although C. elegans has a simple body system and neural circuitry, it exhibits very complicated functions ranging from feeding to locomotion. Investigation of these functions through proteomic analysis of various C. elegans neuropeptides, some of which are not found in the predicted genome sequence, would open a new field of peptidomics. Given the importance of nematode infection in plants and mammalian pathogenesis pathways, proteomics could be applied to investigate the molecular mechanisms underlying plant- or animal-nematode pathogenesis and to identify novel antinematodal drugs. Thus, C. elegans proteomics, in combination of other molecular, biological and genetic techniques, would provide a versatile new tool box for the systematic analysis of gene functions throughout the entire life cycle of this nematode. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA. Source

Yoon J.H.,Konkuk University
Classical and Quantum Gravity | Year: 2014

The canonical formalism of the (2+2) formulation of general relativity of four spacetime dimensions is studied under no symmetry assumptions, where the spacetime is viewed as a local product of a two dimensional base manifold of Lorentzian signature with the vertical space as its complement. The affine null parameter is chosen as the time coordinate whose level surfaces are three dimensional spacelike hypersurfaces. From the first-order action principle, Hamilton's equations of motion and the constraints are obtained, which are found to be equivalent to the Einstein's equations. The constraint algebra is also presented, which has interesting subalgebras such as the infinite dimensional Lie algebra of the diffeomorphisms of the two dimensional vertical space, infinite dimensional Virasoro algebra associated with the two dimensional base manifold, and an analogue of supertranslation. The symmetry algebra may be viewed as a generalization of the BMS or Spi group to a finite distance. © 2014 IOP Publishing Ltd. Source

Cheung K.,Konkuk University | Cheung K.,National Tsing Hua University | Tseng P.-Y.,National Tsing Hua University | Yuan T.-C.,Academia Sinica, Taiwan
Journal of Cosmology and Astroparticle Physics | Year: 2011

Using an effective interaction approach to describe the interactions between the dark matter particle and the light degrees of freedom of the standard model, we calculate the gamma-ray flux due to the annihilation of the dark matter into quarks, followed by fragmentation into neutral pions which subsequently decay into photons. By comparison to the mid-latitude data released from the Fermi-LAT experiment, we obtain useful constraints on the size of the effective interactions and they are found to be comparable to those deduced from collider, gamma-ray line and anti-matter search experiments. However, the two operators induced by scalar and vector exchange among fermionic dark matter and light quarks that contribute to spin-independent cross sections are constrained more stringently by the recent XENON100 data. © 2011 IOP Publishing Ltd and SISSA. Source

Nam M.-H.,Konkuk University
History of Mechanism and Machine Science | Year: 2015

In the course of seven year's astronomical project launched by King Sejong (r. 1418-50) of the Joseon dynasty (1392-1910); beginning in 1432, the Royal Observatory installed fifteen kinds of astronomical equipment and timekeeping devices in the main palace grounds. Among these, five kinds were astronomical instruments. Ten kinds were timekeeping devices. Jang Yeong-sil (Unknown) invented two Striking Clepsydras: Ball-powered Striking Palace Clepsydra employed as a standard timekeeper, and Water- and ball-operated Striking Heavenly Clepsydra as an instrument to edify Neo-Confucian ideology. The Sun-and-Star Time-determining Instrument and its smaller version consisted of a sun- and star-dial mounting equatorial-polar alignment and thread gnomons. Two Small Simplified Armilla were used to observe celestial bodies and/or timekeeping at the palace observatory and Astro-calendric Office, respectively. The sundials, mounting an equatorial-polar alignment and/or all thread-gnomons Scaphe-, Plummet-, Horizontal-, and South-determining, were new and used at the observatory, Astro-claendric Office, military camps, public places and palaces. A portable water-clock, Traveling Clepsydra, was used for the royal family, the Astro-claendric Office and military camps. The Striking Clepsydras, the Sun-and-Star Time-determining Instrument and the Small Simplified Armilla were evaluated as Korean originals in the world history of astronomical instruments and clocks. Inventions and innovations in constructing the timekeeping device at the Royal Observatory attribute in large measure to King Sejong's state-supported science policies. Time-measuring devices are reviewed from the contemporary official records with extant relics and reconstructions. © 2015 Springer Science+Business Media Dordrecht. Source

Jung D.S.,Korea Advanced Institute of Science and Technology | Ko Y.N.,Korea Advanced Institute of Science and Technology | Kang Y.C.,Konkuk University | Park S.B.,Korea Advanced Institute of Science and Technology
Advanced Powder Technology | Year: 2014

We review the effect that various structures and composites synthesized by spray pyrolysis have on the electrochemical performance of next-generation electrodes for medium and large lithium ion batteries. The morphologies of electrode particles in particular have a strong influence on the capacity, power, safety, and cycle life. Recent progress in improving the electrochemical performance of electrodes is provided with a particular focus on electrodes composed of nanoparticles, core-shell or yolk-shell structures, and carbon-based composites. Finally, we propose a direction for future research for high-performance lithium ion batteries incorporating fabrication by spray pyrolysis. © 2013 The Society of Powder Technology Japan. Published by Elsevier B.V. Source

Lee W.H.,Konkuk University | Park Y.D.,Incheon National University
Polymers | Year: 2014

We reviewed recent advances in high-performance organic field-effect transistors (OFETs) based on organic semiconductor/insulator polymer blends. Fundamental aspects of phase separation in binary blends are discussed with special attention to phase-separated microstructures. Strategies for constructing semiconductor, semiconductor/dielectric, or semiconductor/passivation layers in OFETs by blending organic semiconductors with an insulating polymer are discussed. Representative studies that utilized such blended films in the following categories are covered: vertical phase-separation, processing additives, embedded semiconductor nanowires. © 2014 by the authors. Source

Choi S.H.,Seoul 136 713 Republic of Korea | Ko Y.N.,Seoul 136 713 Republic of Korea | Lee J.-K.,Konkuk University | Kang Y.C.,Seoul 136 713 Republic of Korea
Advanced Functional Materials | Year: 2015

A novel anode material for sodium-ion batteries consisting of 3D graphene microspheres divided into several tens of uniform nanospheres coated with few-layered MoS2 by a one-pot spray pyrolysis process is prepared. The first discharge/charge capacities of the composite microspheres are 797 and 573 mA h g-1 at a current density of 0.2 A g-1. The 600th discharge capacity of the composite microspheres at a current density of 1.5 A g-1 is 322 mA h g-1. The Coulombic efficiency during the 600 cycles is as high as 99.98%. The outstanding Na ion storage properties of the 3D MoS2-graphene composite microspheres may be attributed to the reduced stacking of the MoS2 layers and to the 3D structure of the porous graphene microspheres. The reduced stacking of the MoS2 layers relaxes the strain and lowers the barrier for Na+ insertion. The empty nanospheres of the graphene offer voids for volume expansion and pathways for fast electron transfer during repeated cycling. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Sprague I.B.,Washington State University | Dutta P.,Washington State University | Dutta P.,Konkuk University
Numerical Heat Transfer; Part A: Applications | Year: 2011

A mathematical model for laminar flow fuel cells including electrical double layer and ion transport effects is developed. The model consists of the Poisson-Nernst-Plank equations and the modified Navier-Stokes equations to account for the advection of species in the downstream direction. The generalized Frumkin-Butler-Volmer equation is used for the fuel cell kinetics. The finite-volume method is used to develop a system of algebraic equations from the governing partial differential equations, and a numerical algorithm is developed to obtain the results. The accuracy of the 2-D numerical simulation is validated against published results using a 1-D analytical solution. Numerical results show that the concentration distributions for both the neutral species and ions change in both the cross-stream and streamwise directions. An especially interesting result is the change in positive ion concentration within the electrical double layer along the streamwise direction. A study on the importance of the electric body force in the momentum conservation equations is also presented. It is found that the flow results are only affected by the electric body force term at the start of the electrodes and has a negligible impact on device performance results. This model allows us to study both kinetically active (electrodes) and inactive (insulated wall) regions for a microfluidic fuel cell. The mathematical model and numerical simulation will be particularly useful in analyzing the complex behavior that occurs in laminar flow electrochemical devices where a minimum of two spatial dimensions must be considered and the electrical double layer and ion transport cannot be neglected. Copyright © 2011 Taylor & Francis Group, LLC. Source

This paper proposes the active damping control strategy for position sensorless operation of an interior permanent magnet (IPM) motor. The proposed method is applied to both the current controller and the position estimator to control damping characteristics of the IPM drive system. By actively increasing the damping characteristics of the system with the proposed method, the current control and the position estimation loops become immune to parameter variation of the stator resistance which may degrade the accuracy of the position estimator. To analyze the accuracy of the position estimator with and without the proposed method, a small-signal analysis is carried out for low speed operation where the effect of the parameter variation is relatively large due to a low signal-to-noise ratio (SNR). Additionally, an open-loop voltage to angular velocity transfer function including the electrical and the mechanical parameters is investigated. Since no hardware modifications are necessary, the proposed method can be easily implemented just in software routines. Both the simulations and the experimental validations in which the proposed active damping control strategy is incorporated with the existing extended electromotive force (EMF)- based sensorless algorithm are provided to support the effectiveness of the proposed method. © 2016 by the authors. Source

Yoon C.-H.,Sungkyunkwan University | Miah M.A.,Sungkyunkwan University | Kim K.P.,Konkuk University | Bae Y.-S.,Sungkyunkwan University | Bae Y.-S.,CreaGene Research Institute
EMBO Reports | Year: 2010

Cell division cycle 2 (Cdc2) protein is an essential subunit of M-phase kinase (MPK), which has a key role in G2/M transition. Even though the control of MPK activity has been well established with regard to the phosphorylation of Cdc2 at Thr 14 and/or Tyr 15 and Thr 161, little is known about the proteolytic control of Cdc2. In this study, we observed that Cdc2 was downregulated under genotoxic stresses and that double-stranded RNA-activated protein kinase (PKR) was involved in the process. The PKR-mediated Tyr4 phosphorylation triggered Cdc2 ubiquitination. Phospho-mimic mutations at the Tyr 4 residue (Y4D or Y4E) caused significant ubiquitination of Cdc2 even in the absence of PKR. Our findings demonstrate that (i) PKR, Ser/Thr kinase, phosphorylates its new substrate Cdc2 at the Tyr 4 residue, (ii) PKR-mediated Tyr 4-phosphorylation facilitates Cdc2 ubiquitination and proteosomal degradation, (iii) unphosphorylated Tyr 4 prevents Cdc2 ubiquitination, and (iv) downstream from p53, PKR has a crucial role in G2 arrest and triggers Cdc2 downregulation under genotoxic conditions. © 2010 EuropeEan MoleEcular Biology Oorganization. Source

Jin B.,University of North Carolina at Greensboro | Park J.Y.,Konkuk University | Kim H.-S.,University of Delaware
Behaviour and Information Technology | Year: 2010

A growing number of firms are using online communities (OCs) as integral parts of their strategies because of the value an OC provides to a firm. This study maintains the commitment to an OC to be critical in developing a sustainable OC and examines how members' commitment to an OC develops in the context of OCs hosted by firms and freely available to anyone. Built on the social exchange theory, the proposed model posits that two aspects of OC attributes (Sociability and Usability) facilitate members' participation in an OC, as well as bring social and functional benefits to participants. In return for the benefits gained from OC participation, participants reciprocate with affective and calculative commitment to the OC. Data were collected via online survey from OC participants who were 18 years old or above and resided in South Korea. An analysis of 595 cases supported the proposed model. Results indicated that the members' perceived social benefits from active OC participation led to an affective commitment to the OC, while members' perceived functional benefits led to a calculative commitment to the OC. Theoretical and managerial implications were suggested based on the findings. © 2010 Taylor & Francis. Source

Lee M.W.,Sungkyunkwan University | Rhim H.,Sungkyunkwan University | Ik Cha D.,Sungkyunkwan University | Jun Kim Y.,Konkuk University | Lim H.K.,Sungkyunkwan University
Journal of Vascular and Interventional Radiology | Year: 2013

Purpose To assess whether fusion of conventional ultrasonography (US) with liver computed tomography/magnetic resonance images for planning US for percutaneous radiofrequency (RF) ablation can reduce false-positive detection and enhance lesion detectability of small hepatocellular carcinomas (HCCs) on conventional US. Materials and Methods This retrospective study was approved by the institutional review board, and informed consent was waived. A total of 137 patients with single HCCs (mean ± standard deviation, 1.7 ± 0.6 cm; range, 1.1-3.0 cm) were included. Planning US was performed by two radiologists by using conventional US first and fusion imaging later in the same session. The false-positive detection rate of conventional US was assessed with the results of fusion imaging used as a reference standard. True-positive detection rates on conventional US and fusion imaging were compared by McNemar test. Initially undetectable HCCs on conventional US that became detectable after image fusion were also assessed. Results The false-positive detection rate of conventional US was 7.7% (nine of 117). Overall true-positive detection rates on conventional US and fusion imaging were 78.8% (108 of 137) and 90.5% (124 of 137), respectively (P =.0002); the rates were significantly different between conventional US and fusion imaging for HCCs smaller than 2.0 cm, but not for HCCs 2.0 cm or larger. Of 20 initially undetectable HCCs on conventional US, nine (45.0%) became detectable after image fusion. Conclusions Fusion imaging for planning US for percutaneous RF ablation can reduce false-positive detection and enhance lesion detectability of small HCCs on conventional US. © 2013 SIR. Source

Kima D.-M.,Pusan National University | Rahmanb M.A.,Konkuk University | Do M.H.,Pusan National University | Ban C.,Pohang University of Science and Technology | Shim Y.-B.,Pusan National University
Biosensors and Bioelectronics | Year: 2010

An amperometric chloramphenicol (CAP) immunosensor was fabricated by covalently immobilizing anti-chloramphenicol acetyl transferase (anti-CAT) antibody on cadmium sulfide nanoparticles (CdS) modified-dendrimer that was bonded to the conducting polymer (poly 5, 2': 5', 2"-terthiophene-3'-carboxyl acid (poly-TTCA)) layer. The AuNPs, dendrimers, and CdS nanoparticles were deposited onto the polymer layer in order to enhance the sensitivity of the sensor probes. The particle sizes were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The immobilization of dendrimers, CdS, and anti-CAT were confirmed using energy disruptive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM) techniques. The detection of CAP was based on the competitive immuno-interaction between the free- and labeled-CAP for active sites of the anti-CAT. Hydrazine was used as the label for CAP, and it electrochemically catalyzed the reduction of H2O2 at -0.35V vs. Ag/AgCl. Under optimized conditions, the proposed immunosensor exhibited a linear range of CAP detection between 50 pg/mL and 950 pg/mL, and the detection limit was 45 pg/mL. The immunosensor was examined in real meat samples for the analysis of CAP. © 2009 Elsevier B.V. Source

Jung C.-Y.,Hanyang University | Kim W.-J.,Konkuk University | Yi S.-C.,Hanyang University
International Journal of Hydrogen Energy | Year: 2012

In a typical proton exchange membrane fuel cell (PEMFC), a gas crossover brings parasitic reaction, such as hydrogen and carbon oxidation at the cathode and oxygen reduction at the anode, which reduces open circuit potential (OCP) because of undesired potential mixing. Therefore, a two-dimensional computational fluid dynamics model was formulated to elucidate the variation of cell polarization, as the parameters affecting the mixed-potential effect change. The present model was validated by comparing the simulated cell polarization with experimentally measured cell polarization. The membrane electrode assembly was prepared by the decal transfer method, which gives uniform electrode formation. Model comparisons were also conducted to clearly state the significance of the fuel crossover and carbon oxidation reaction on OCP decrease. The results have shown that model prediction fits experimental data with an acceptable range of error, under two different relative humidity conditions of 50 and 100%. In addition, further investigations were conducted on (i) effect of gas permeation coefficient in membrane, (ii) effect of membrane thickness and (iii) effect of carbon oxidation and their influences on OCP and cell polarization are discussed. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Jung C.-Y.,Hanyang University | Kim W.-J.,Konkuk University | Yi S.-C.,Hanyang University
International Journal of Hydrogen Energy | Year: 2012

For low interfacial resistance and feasibility of forming catalyst layer (CL), decal transfer (DT) is considered as one of the most effective methods for preparing a membrane electrode assembly. However, optimization of the catalyst ink composition is necessary, because of the complexity of the CL. Here, 1-propanol is adsorbed onto the CL coated onto the decal, as a swelling agent, for complete transfer of the CL onto Nafion membrane. Using this methodology, flat and complete DT is achieved at the hot-pressing conditions of 60 °C and 5 MPa. For optimization, the solvent-to-carbon ratio (SCR) and Nafion-to-carbon ratio (NCR) are controlled to achieve improved cell performance. In this study, by considering the morphology of CL and the cell performance when CL is annealed at temperatures sufficiently below the boiling point of the solvent, optimized SCR and NCR values of approximately 12.0 and 0.65, respectively, are obtained. In addition, microstructure, thickness and various electrochemical properties of the CLs are examined in detail. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Muthusami S.,Chungbuk National University | Prabakaran D.S.,Chungbuk National University | Yu J.-R.,Konkuk University | Park W.-Y.,Chungbuk National University
Cancer Letters | Year: 2014

The role of Fused Toes Homolog (FTS) in epidermal growth factor (EGF) induced epithelial-mesenchymal transition (EMT) in cervical cancer cells was studied. EGF treatment induced the change of EMT markers and increased cell migration. EGF treatment also increased phosphorylated EGFR and ERK and nuclear level of ATF-2. The binding of ATF-2 to the promoter region of FTS was evidenced after EGF treatment. Pretreatment with PD98059 and gefitinib prevented EGF-induced FTS expression. FTS silencing reduced EMT and cell migration by EGF treatment. These results demonstrate a novel function for FTS in EGF-mediated EMT process. © 2014 Elsevier Ireland Ltd. Source

Lim J.-H.,Konkuk University
Korean Journal of Physiology and Pharmacology | Year: 2014

Although interleukin-11 (IL-11) has been reported to be elevated in hypoxic tumors and has been associated with a poor prognosis in various cancers, little is known about its precise role in promoting metastasis in hypoxic tumors. In the present study, the molecular mechanism underlying the effects of IL-11 on MDA-MB-231 breast cancer cells migration and invasion in relation to metastasis under hypoxic conditions has been defined. Inhibition of IL-11 expression or function using small interfering RNA (siRNA) or a neutralizing antibody attenuated hypoxic MDA-MB-231 breast cancer cell migration and invasion through down-regulation of matrix metalloproteinases (MMPs) and activation of epithelial-to-mesenchymal transition (EMT) related gene expression. In addition, hypoxia-induced IL-11 increased STAT3 phosphorylation and STAT3 knockdown suppressed hypoxic MDA-MB-231 breast cancer cell invasion due to reduced MMP levels and reprogrammed EMT-related gene expression. These results suggest that one of the hypoxic metastasis pathways and the regulation of this pathway could be a potential target for novel cancer therapeutics. Source

Lee J.-P.,Konkuk University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Unparticle contributions to the recently measured decay mode B s→μ+μ- are analyzed. We consider only the scalar unparticles because vector unparticles are expected to provide negligible contributions. Assuming that the relevant coupling constants are real, we present allowed regions of coupling constants and the scaling dimension of the scalar unparticle. While the measured value of the branching ratio is very close to the standard model predictions, one cannot exclude the possible contributions from unparticles. © 2013 American Physical Society. Source

Chang J.,National Tsing Hua University | Cheung K.,National Tsing Hua University | Cheung K.,Konkuk University | Lu C.-T.,National Tsing Hua University | Yuan T.-C.,Academia Sinica, Taiwan
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

More evidence has now been collected at the Large Hadron Collider suggesting the new 125-126 GeV boson is likely the long-sought Higgs boson in the standard model. One pressing question theorists continue to ask is whether this Higgs boson is a lone player responsible for the full electroweak symmetry breaking. Current data still allow room for additional Higgs bosons or some other UV physics that may play a partial role in electroweak symmetry breaking as well. We use the WW scattering to investigate such a possibility, using the two-Higgs-doublet model as a prototype. The WW scattering becomes strong when the extra Higgs bosons are very heavy. We study the sensitivity of these strong WW scattering signals at the 13 TeV Large Hadron Collider. © 2013 American Physical Society. Source

Yu M.H.,Konkuk University | Lee J.M.,Seoul National University | Baek J.H.,Seoul National University | Han J.K.,Seoul National University | Choi B.-I.,Seoul National University
American Journal of Roentgenology | Year: 2014

OBJECTIVE. The purpose of this study was to investigate the MRI features of gastrointestinal stromal tumors (GISTs) with special emphasis on the dynamic enhancement pattern and findings of diffusion restriction. MATERIALS AND METHODS. Forty-two patients with pathologically proven GISTs who underwent MRI that included dynamic contrast-enhanced and diffusion-weighted imaging (DWI) were included in this study. Two abdominal radiologists analyzed the MR images in consensus regarding the morphologic features, enhancement degree and pattern, and findings of diffusion restriction. The mean apparent diffusion coefficient (ADC) values of the tumors were measured by one of the radiologists. The MRI features and mean ADC values were analyzed with respect to tumor size and malignancy risk. RESULTS. Small GISTs (≤ 5 cm, n = 25) appeared as round tumors with strong and homogeneous arterial enhancement and a persistent enhancement pattern. Large GISTs (> 5 cm, n = 17) appeared as lobulated tumors with mild heterogeneous gradual enhancement, and they frequently exhibited intratumoral cystic change (n = 13). The prevalence of intratumoral cystic change was higher in the moderate to high risk group than in very low to low risk group (p < 0.05). There was negative linear correlation between the mean ADC values and the malignancy risk of GISTs (r = -0.670, p < 0.05). CONCLUSION. Small GISTs had MRI features different from the well-known imaging features of large GISTs. The presence of intratumoral cystic change and a low mean ADC value may be helpful for predicting the high malignancy potential of GISTs. © American Roentgen Ray Society. Source

Balasingam S.K.,Ulsan National Institute of Science and Technology | Kang M.G.,Electronics and Telecommunications Research Institute | Jun Y.,Konkuk University
Chemical Communications | Year: 2013

A step towards commercialization of dye-sensitized solar cells (DSSCs) requires more attention to engineering aspects, such as flexibility, the roll to roll fabrication process, the use of cost effective materials, etc. In this aspect, advantages of flexible DSSCs attracted many researchers to contemplate the transparent conducting oxide coated flexible plastic substrates and the thin metallic foils. In this feature article, the pros and cons of these two kinds of substrates are compared. The flexible dye-sensitized solar cells fabricated using metal substrates are briefly discussed. The working electrodes of DSSCs fabricated on various metal substrates, their fabrication methods, the effect of high temperature calcination and drawbacks of back illumination are reviewed in detail. A few reports on the flexible metal substrate based counter electrodes that could be combined with the plastic substrate based working electrodes are also covered at the end. © 2013 The Royal Society of Chemistry. Source

Han T.,University of Pittsburgh | Kim I.-W.,University of Michigan | Song J.,Konkuk University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The kinematics of a final state system with two invisible particles and two visible particles can develop cusped peak structures. This happens when the system has a fixed invariant mass (such as from a narrow resonant particle decay or with a fixed collision c.m. energy) and undergoes decays of two on-shell intermediate particles. Focusing on the antler decay topology, we derive general analytic expressions for the invariant mass distribution and the kinematic cusp position. The sharp cusp peaks and the endpoint positions can help to determine the masses of the missing particles and the intermediate particles. We also consider transverse momentum variables and angular variables. In various distributions the kinematic cusp peaks are present and pronounced. We also study the effects on such kinematic cusp structures from realistic considerations including finite decay widths, the longitudinal boost of the system, the initial state radiation, and spin correlations. © 2013 American Physical Society. Source

Han T.,University of Pittsburgh | Kim I.-W.,University of Michigan | Song J.,Konkuk University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Three-step cascade decays into two invisible particles and two visible particles via two intermediate on-shell particles develop cusped peak structures in several kinematic distributions. We study their basic properties and demonstrate that the masses of the missing particles and the intermediate particles can be determined by the cusp and endpoint positions. Effects from realistic considerations such as finite decay widths, the longitudinal boost of the mother particle, the initial state radiation, and spin correlations are shown to be under control for the processes illustrated. © 2013 American Physical Society. Source

Han S.G.,Konkuk University
Journal of Nanoscience and Nanotechnology | Year: 2016

Multi-walled carbon nanotubes (MWCNT) possess unique physic-chemical properties for a diverse utilization. However, potential toxic effects also have been raised. To test whether pulmonary exposure of MWCNT induces toxicity in pulmonary and cardiovascular system, apolipoprotein E-deficient (apoE-/-) mice fed a regular diet were exposed to MWCNT (40 μg, once each week for 16 consecutive weeks) by pharyngeal aspiration. Mice were sacrificed on 1 and 7 d following the last exposure. Bronchoalveolar lavage (BAL) fluid, BAL cells, urine, aortas and plasma were obtained to evaluate pulmonary toxicity, oxidative stress and atherosclerotic lesion formation. Cell-free BAL fluid measurements showed significantly elevated levels of total protein, lactate dehydrogenase, surfactant protein-D, and mucin in MWCNT-exposed mice at 1 and 7 d post-exposure, compared to control. Total BAL cells and polymorphonuclear leukocytes counts were markedly increased in MWCNTexposed mice at both time points. However, aortic atherosclerotic lesions, total plasma cholesterol levels and urinary 8-hydroxy-2?-deoxyguanosine were not significantly altered by MWCNT exposure. Results indicate that sub-chronic lung exposure of MWCNT exerts toxicity in mouse lungs without apparent atherogenic effects. © 2016 American Scientific Publishers All rights reserved. Source

Bae S.H.,Konkuk University
Pediatric Gastroenterology, Hepatology and Nutrition | Year: 2013

The field of stem cell research has been rapidly expanding. Although the clinical usefulness of research remains to be ascertained through human trials, the use of stem cells as a therapeutic option for currently disabling diseases holds fascinating potential. Many pediatric gastrointestinal tract diseases have defect in enterocytes, enteric nervous system cells, smooth muscles, and interstitial cells of Cajal. Various kinds of therapeutic trials using stem cells could be applied to these diseases. This review article focuses on the recent achievements in stem cell applications for pediatric gastrointestinal tract diseases. © 2014 by The Korean Society of Pediatric Gastroenterology, Hepatology and Nutrition. Source

Lim H.J.,Konkuk University | Wang H.,CAS Institute of Zoology
Journal of Clinical Investigation | Year: 2010

Much of our knowledge of human uterine physiology and pathology has been extrapolated from the study of diverse animal models, as there is no ideal system for studying human uterine biology in vitro. Although it remains debatable whether mouse models are the most suitable system for investigating human uterine function(s), gene-manipulated mice are considered by many the most useful tool for mechanistic analysis, and numerous studies have identified many similarities in female reproduction between the two species. This Review brings together information from studies using animal models, in particular mouse models, that shed light on normal and pathologic aspects of uterine biology and pregnancy complications. Source

Gaddam et al1 has reported a study entitled "Persistence of nondysplastic Barrett's esophagus (BE) identifies patients at lower risk for esophageal adenocarcinoma (EAC): results from a large multicenter cohort." in the September issue of Gastroenterology 2013. Using outcomes of a large multicenter cohort study of patients with BE, the authors evaluated how the persistence of BE without dysplasia over multiple consecutive surveillance using esophagogastroduodenoscopic examinations could have an effect in risk stratification of patients with BE. Based on the number of consecutive surveillance endoscopies presenting BE without dysplasia, they identified 5 groups of patients with BE without dysplasia. Group 1 was determined as the patients with BE without dysplasia at their first esophagogastroduodenoscopy (EGD). Group 2 was determined as the patients with BE without dysplasia at their first 2 consecutive EGDs. Similarly, groups 3, 4 and 5 were determined as the patients with BE without dysplasia at 3, 4, and 5 consecutive surveillance EGDs. A logistic regression model was used to determine whether the persistence of BE without dysplasia had independent effect for the development of esophageal high grade dysplasia (HGD) and/or EAC. In results, a total of 1,401 patients with BE were finally included (median follow-up period; 5.0 ± 3.9 years). The annual risk of HGD and/or EAC in group 1 (n = 1,401), group 2 (n = 826), group 3 (n = 484), group 4 (n = 280) and group 5 (n = 173) was 0.75%, 0.57%, 0.41%, 0.44% and 0.00%, respectively (P for trend = 0.021). The persistence of BE without dysplasia, based on multiple surveillance endoscopies, was associated with a gradually lower likelihood of progression to HGD and/or EAC (OR, 0.67; 95% CI, 0.51-0.91; P < 0.01), after adjusting for age, sex and length of BE. Through these results, the authors suggested that the persistence of BE without dysplasia over several endoscopic examinations could identify patients who are at low risk for development of HGD and/or EAC, and after all, these findings support lengthening surveillance intervals or discontinuing surveillance in the patients with persistence of BE without dysplasia. © 2013 The Korean Society of Neurogastroenterology and Motility. Source

Song B.G.,Konkuk University
Heart and Lung: Journal of Acute and Critical Care | Year: 2013

Uhl's anomaly is a myocardial disorder of unknown cause that is characterized by complete or partial absence of the myocardium of the right ventricle. The disease may represent a cause of right heart dilatation and failure. Although most cases of Uhl's anomaly end fatally in infancy or childhood, an initial presentation during adulthood has been reported in rare cases. We report a very rare case of partial absence of the right ventricular musculature or partial Uhl's anomaly that incidentally found in asymptomatic adult man. © 2013 Elsevier Inc. Source

Kim J.-Y.,University of Texas at Austin | Lee W.H.,University of Texas at Austin | Lee W.H.,Konkuk University | Suk J.W.,University of Texas at Austin | And 7 more authors.
Advanced Materials | Year: 2013

Phenyl isocyanate-functionalized and hydrazine-reduced reduced graphene oxide (rG-O) is treated to produce chlorinated rG-O (Cl-rG-O) platelets. The dielectric constant of the composite film containing Cl-rG-O shows a 5.5-fold increase over that of composites of untreated rG-O and this cyanoethyl-based polymer, a consequence of the combination of polar and polarizable C-Cl bonds and the increased interfacial polarization. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Lee S.G.,Pohang University of Science and Technology | Kim H.,Pohang University of Science and Technology | Choi H.H.,Pohang University of Science and Technology | Bong H.,Pohang University of Science and Technology | And 3 more authors.
Advanced Materials | Year: 2013

The evaporation-induced self-alignment of semiconductor nanowires is achieved using wrinkled elastomeric templates. The wrinkled templates, which have a surface topography that can be tuned via changes in the mechanical strain, are used as both a template to align the nanowires and as a stamp to transfer the aligned nanowires to target substrates. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Chon D.-H.,University of Massachusetts Amherst | Rome M.,University of Massachusetts Amherst | Kim Y.M.,University of Massachusetts Amherst | Park K.Y.,Konkuk University | Park C.,University of Massachusetts Amherst
Water Research | Year: 2011

To investigate the mechanism of sludge reduction in the anaerobic side-stream reactor (SSR) process, activated sludge with five different sludge reduction schemes were studied side-by-side in the laboratory. These are activated sludge with: 1) aerobic SSR, 2) anaerobic SSR, 3) aerobic digester, 4) anaerobic digester, and 5) no sludge wastage. The system with anaerobic SSR (system #2) was the focus of this study and four other systems served as control processes with different functions and purposes. Both mathematical and experimental approaches were made to determine solids retention time (SRT) and sludge yield for the anaerobic SSR process. The results showed that the anaerobic SSR process produced the lowest solids generation, indicating that sludge organic fractions degraded in this system are larger than other systems that possess only aerobic or anaerobic mode. Among three systems that involved long SRT (system #1, #2, and #5), it was only system #2 that showed stable sludge settling and effluent quality, indicating that efficient sludge reduction in this process occurred along with continuous generation of normal sludge flocs. This observation was further supported by batch anaerobic and aerobic digestion data. Batch digestion on sludges collected after 109 days of operation clearly demonstrated that both anaerobically and aerobically digestible materials were removed in activated sludge with anaerobic SSR. In contrast, sludge reduction in the aerobic SSR process or no wastage system was achieved by removal of mainly aerobically digestible materials. All these results led us to conclude that repeating sludge under both feast/fasting and anaerobic/aerobic conditions (i.e., activated sludge with anaerobic SSR) is necessary to achieve the highest biological solids reduction with normal wastewater treatment performance. © 2011 Elsevier Ltd. Source

Park C.S.,Konkuk University | Sundstrom L.,Ericsson AB | Wallen A.,Ericsson AB | Khayrallah A.,Ericsson AB
IEEE Communications Magazine | Year: 2013

Carrier aggregation is a key feature of 3GPP LTE that addresses the support of higher data rates and utilization of fragmented spectrum holdings. In this article, the relevant design challenges of terminals are discussed. The transmitter architectures are reviewed, and the minimum amount of power amplifier back-offs is evaluated. In addition, several receiver architectures are compared from the perspective of design tradeoff. The radio impairments affecting the receiver performance are analyzed and the simulation results are provided. The corresponding silicon implementation is presented together with the measurement results. © 1979-2012 IEEE. Source

Zhao Z.,Enphase Energy | Lai J.-S.,Virginia Polytechnic Institute and State University | Cho Y.,Konkuk University
IEEE Transactions on Industrial Electronics | Year: 2013

Three dual-mode boost-buck-derived inverters with smooth transition between modes have been proposed: 1) boost-full bridge inverter; 2) boost-H5 inverter; 3) boost-dual buck inverter. For the same topologies, in conventional control method, the first stage is needed to boost input voltage to a constant high voltage, and the second stage is for sinusoidal inverting. However, in the proposed three inverters, either buck or boost mode works at a single time, thus, only one switch works at a high switching frequency. In this way, a lot switching loss can be reduced, and moreover, since the voltage across the middle capacitor is smaller than the conventional constant high voltage, the further switching loss mitigation is possible. In order to achieve smooth transition between the two modes, a double-carrier-based sinusoidal pulse width modulation (SPWM) is proposed. Other than this, three advanced modulation methods are proposed: 1) double-carrier with different frequencies; 2) double-carrier with different magnitudes; and 3) double-carrier with different frequencies and magnitudes. Following that, the loss distribution in every component is provided and the California Energy Commission efficiency of these inverters under different input voltage conditions is compared. Finally, the experimental results show the dual-mode double-carrier-based SPWM inverter can improve the efficiency by 2% than the traditional constant dc bus voltage solutions. © 2012 IEEE. Source

Park G.D.,Korea University | Lee J.-H.,Korea University | Lee J.-K.,Konkuk University | Kang Y.C.,Korea University
Nano Research | Year: 2014

In this study, for the first time, polymeric precursors have been used in the preparation of yolk-shell powders using a large-scale spray drying process. An esterification reaction between the carboxyl group of citric acid and the hydroxyl group of ethylene glycol inside the droplet produced organic polymers during the drying process of the droplet. During the spray drying process, the polymeric precursors enabled the formation of multi-shell cobalt oxide yolk-shell powders with superior electrochemical properties. The maximum number of shells of the particles in the yolk-shell powders post-treated at 300, 400, and 500 °C were six, five, and four, respectively. The initial discharge capacities of the cobalt oxide yolk-shell powders post-treated at 300, 400, and 500 °C were 1,188, 1,331, and 1,110 mAh·g−1, and their initial charge capacities were 868, 1,005, and 798 mAh·g−1, respectively. The discharge capacities of the powders post-treated at 300, 400, and 500 °C after 100 cycles were 815, 958, and 670 mAh·g−1, respectively, and their corresponding capacity retentions measured after the first cycles were 92%, 93%, and 82%, respectively. The pure phase Co3O4 yolk-shell powders post-treated at 400 °C had low charge transfer resistance and high lithium-ion diffusion rate.[Figure not available: see fulltext.]. © 2014, Tsinghua University Press and Springer-Verlag Berlin Heidelberg. Source

Park H.,Pohang University of Science and Technology | Yoon J.,Konkuk University | Kim K.,Pohang University of Science and Technology
Expert Systems with Applications | Year: 2013

Under the open innovation paradigm, identification of application areas of the internally developed technologies is important to maximize the profits from them. However, many companies have failed to identify opportunity for additional applications. The fundamental reason is that companies have insufficient understanding of the potential applications of their technologies, because different industries use far different technologies and technological terminologies. However, technologies can be linked with outside industries by analyzing them from the functional perspective, because functions used in different industries are generally similar. Therefore, this article proposes a function-based patent analysis to identify the potential application areas of a technology. In general, technologies in a patent are invented for use in a specific industry, and thus a patent can be categorized into a specific industry. By identifying patents which contain a specific function, industries that use the function can be identified. Industries in which the importance of the function is relatively high can be considered as areas in which technologies performing the function have potential to be applied, and the proposed indexes evaluate the relative importance of the function within each industry. Finally, the practical usefulness of the proposed method was verified by identifying the potential areas in which vortex reduction technology can be applied. © 2013 Elsevier Ltd. All rights reserved. Source

Kang H.,TU Chemnitz | Lee C.,FLEXIBLE DISPLAY | Shin K.,Konkuk University
Control Engineering Practice | Year: 2013

For mass manufacturing of printed electronics using roll-to-roll printing, high-resolution register control among multi-layers is required. A mathematical model of a machine directional (MD) register was derived, where the compensation method was proposed to cancel out the upstream disturbance of the MD register. The proposed MD register model and compensator could be used to improve the performance of the MD register controller in multi-layer roll-to-roll printed electronics. The proposed compensator was experimentally verified at various operating conditions. The results show that the proposed compensator improves the control performance of the MD register in overcoming upstream disturbances. © 2013. Source

Park H.,Pohang University of Science and Technology | Kim K.,Pohang University of Science and Technology | Choi S.,Samsung | Yoon J.,Konkuk University
Expert Systems with Applications | Year: 2013

Patent intelligence - the transformation of content found in multiple patents into technical, business, and legal insight - is considered a key factor in gaining a competitive advantage in technologically competitive business environments. Although keyword-based patent intelligence tools are widely used due to their simplicity and ease of use, they are limited in that they cannot represent key technological concepts and inventive knowledge by relying only on the frequency of occurrence of defined keywords. As a remedy, this paper proposes a Subject-Action-Object (SAO)-based patent intelligence system. SAO structures that can be extracted from textual patent information are known as the expertise and inventive findings of the relevant patent. On the basis of semantic analysis of patent SAO structures, our proposed intelligence system constructs patent maps and patent networks. Building on the maps and networks, the system provides specific functionalities including identification of technology trends and significant patents, detection of novel technologies, and identification of potential infringement. This paper describes the architecture of our proposed patent intelligence system in detail, and illustrates the system's functionalities using case studies. We anticipate that our proposed system will be incorporated into the technology planning process to assist experts in the formulation of technology strategies. © 2012 Elsevier B.V. All rights reserved. Source

Kim J.,Konkuk University | Ma J.,University of Illinois at Urbana - Champaign
Bioinformatics | Year: 2014

Summary: We developed PSAR-Align, a multiple sequence realignment tool that can refine a given multiple sequence alignment based on suboptimal alignments generated by probabilistic sampling. Our evaluation demonstrated that PSAR-Align is able to improve the results from various multiple sequence alignment tools. © 2013 The Author 2013. Published by Oxford University Press. All rights reserved. Source

Han S.,Konkuk University
Systems and Control Letters | Year: 2010

This paper presents a closed-form solution to the discrete-time Kalman filter and its applications. We first represent the Kalman filter in terms of model parameters without using the Riccati equation and requiring any artificial conditions such as invertibility of a system matrix and no system noises. Replacing the initial time with the fixed-lag time to achieve the finite memory with respect to inputs and outputs, and choosing the proper initial covariances on the recent finite horizon, we easily obtain the minimum variance finite memory filter and then propose its iterative computation algorithm. As another application, a closedform solution to the difference Riccati equation on the finite horizon is utilized to obtain a stabilizing gain matrix of a Luenberger-type filter as in Ackermann's formula. © 2010 Elsevier B.V. All rights reserved. Source

Withania somnifera is an important medicinal plant that contains withanolides as bioactive compounds. We have investigated the effects of macroelements and nitrogen source in hairy roots of W. somnifera with the aim of optimizing the production of biomass and withanolide A content. The effects of the macroelements NH4NO3, KNO3, CaCl2, MgSO4 and KH2PO4 at concentrations of 0, 0. 5, 1. 0, 1. 5 and 2. 0× strengths and of nitrogen source [NH4 +/NO3 - (0. 00/18. 80, 7. 19/18. 80, 14. 38/18. 80, 21. 57/18. 80, 28. 75/18. 80, 14. 38/0. 00, 14. 38/9. 40, 14. 38/18. 80, 14. 38/28. 20 and 14. 38/37. 60 mM)] in Murashige and Skoog medium were evaluated for biomass and withanolide A production. The highest accumulation of biomass (139. 42 g l-1 FW and 13. 11 g l-1 DW) was recorded in the medium with 2. 0× concentration of KH2PO4, and the highest production of withanolide A was recorded with 2. 0× KNO3 (15. 27 mg g-1 DW). The NH4 +/NO3 - ratio also influenced root growth and withanolide A production, with both parameters being larger when the NO3 - concentration was higher than that of NH4 +. Maximum biomass growth (148. 17 g l-1 FW and 14. 79 g l-1 DW) was achieved at NH4 +/NO3 - ratio of 14. 38/37. 60 mM, while withanolide A production was greatest (14. 68 mg g-1 DW) when the NH4 +/NO3 - ratio was 0. 00/18. 80 mM. The results are useful for the large scale cultivation of Withania hairy root culture for the production of withanolide A. © 2012 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków. Source

Kim J.,Konkuk University
International Journal of Technology Management | Year: 2010

Industrial policy and technology policy share common elements, yet the two differ in their philosophical basis, impacts on economy and society and the scope of policies. This paper, noting the salience, attempted to review the characteristics that make the policy approaches similar and different and lead to a discussion on why industrial policy has been 'evolved' into a technology policy approach, especially with regard to technology development. Then, this paper tried to present partial but strong evidence to support the argument of shifting emphasis from industrial to technology policy. Copyright © 2010 Inderscience Enterprises Ltd. Source

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). Source

Lee S.-W.,Pusan National University | Kouba J.,Natural Resources Canada | Schutz B.,University of Texas at Austin | Kim D.H.,National Meteorological Satellite Center | Lee Y.J.,Konkuk University
Journal of Geodesy | Year: 2013

This paper addresses real-time monitoring of the precipitable water vapor (PWV) from GNSS measurements and presents some results obtained from 6-month long GNSS PWV experiments using international and domestic GNSS networks. In the real-time GNSS PWV monitoring system a server/client structure is employed to facilitate formation of PWV networks and single-differenced GNSS measurements are utilized to mitigate errors in GNSS satellites' orbits and clocks. An issue relating to baseline length between the server and clients is discussed in detail and as a result the PWV monitor is configured to perform in two modes depending on the baseline length. The server estimates sequentially the zenith wet delay of the individual stations, which is then converted into the PWV of the stations. We evaluate system performance by comparing the real-time PWV solution with reference solutions including meteorological measurements obtained with radiosondes and deferred-time precision GNSS PWV solutions. Results showed that the standard deviation of difference between the real-time PWV and the reference solutions ranged from 2.1 to 3.4 mm in PWV for a 6-month long comparison, which was improved to 1.4 to 2.9 mm by reducing comparison period to 20 days in winter. © 2013 Springer-Verlag Berlin Heidelberg. Source

Kim K.H.,Konkuk University
The Korean journal of hepatology | Year: 2010

Infection of hepatitis B virus (HBV) is a main cause of liver diseases including hepatitis, cirrhosis and hepatocellular carcinoma (HCC). Among the HBV-encoded proteins, the HBV X protein (HBx) has been suspected to be strongly involved in HBV-associated liver pathogenesis. HBx, a virally encoded multifunctional regulator, has been shown to induce apoptosis, anti-apoptosis, proliferation, and transformation of cells depending on the cell lines, model systems used, assay protocols, and research groups. Among the several activities of HBx, the pro-apoptotic function of HBx will be discussed in this review. Given that the disruption of apoptosis pathway by HBx contributes to the liver pathogenesis, a better understanding of the molecular interference in the cellular pro-apoptotic networks by HBx will provide useful clues for the intervention in HBV-mediated liver diseases. Source

Chan S.S.,Konkuk University
Gut and Liver | Year: 2010

Minimally invasive therapy is currently invaluable for the treatment of biliary stones. Clinicians should be familiar with the various endoscopic modalities that have been evolving. I reviewed the treatment of biliary stones from the common practice to pioneering procedures, and here I also briefly summarize the results of many related studies. Lithotripsy involves procedures that fragment large stones, and they can be roughly classified into two groups: intracorporeal modalities and extracorporeal shock-wave lithotripsy (ESWL). Intracorporeal modalities are further divided into mechanical lithotripsy (ML), electrohydraulic lithotripsy, and laser lithotripsy. ESWL can break stones by focusing high-pressure shock-wave energy at a designated target point. Balloon dilation after minimal endoscopic sphincterotomy (EST) is effective for retrieving large biliary stones without the use of ML. Peroral cholangioscopy provides direct visualization of the bile duct and permits diagnostic procedures or therapeutic interventions. Biliary stenting below an impacted stone is sometimes worth considering as an alternative treatment in elderly patients. This article focuses on specialized issues such as lithotripsy rather than simple EST with stone removal in order to provide important information on state-of-the-art procedures. Source

Santandrea F.,Gothenburg University | Gorelik L.Y.,Chalmers University of Technology | Shekhter R.I.,Gothenburg University | Jonson M.,Gothenburg University | And 2 more authors.
Physical Review Letters | Year: 2011

We show that the vibrations of a nanomechanical resonator can be cooled to near its quantum ground state by tunneling injection of electrons from a scanning tunneling microscope tip. The interplay between two mechanisms for coupling the electronic and mechanical degrees of freedom results in a bias-voltage-dependent difference between the probability amplitudes for vibron emission and absorption during tunneling. For a bias voltage just below the Coulomb blockade threshold, we find that absorption dominates, which leads to cooling corresponding to an average vibron population of the fundamental bending mode of 0.2. © 2011 American Physical Society. Source

Nguyen H.-A.-D.,FLEXIBLE DISPLAY | Lee C.,FLEXIBLE DISPLAY | Shin K.-H.,Konkuk University
Robotics and Computer-Integrated Manufacturing | Year: 2013

The roll-to-roll printing processes have recently been applied for the manufacturing of printed electronics due to their advantages, such as their high-throughput capabilities and low associated costs. In a roll-to-roll printing machine, a web or substrate is moved from an unwinding roll to a winding roll. During printing, the operating tension is important for correct substrate handling to prevent substrate defects, such as wrinkles, scratches and breaks. Accordingly, the operating conditions of the moving web can affect the quality of the printed pattern. In this study, a mathematical model has been developed to predict the thickness and surface roughness of printed patterns. Because the dynamics of roll-to-roll printing systems are complicated and non-linear, a statistical model is preferred. A full factorial method has been used with four independent variables: operating tension, print speed, ink viscosity and theoretical transfer volume. This model accurately predicted the surface roughness and thickness of the printed pattern. © 2012 Elsevier Ltd. All rights reserved. Source

Yoon K.,Konkuk University
Signal Processing: Image Communication | Year: 2013

Advances in media technologies brought so-called 4-D movies to your neighbour. The 4-D movies represent movies (preferably in 3-D) with additional sensory effects such as motion chairs and wind effects. We present an end-to-end framework to provide sensory effects for home theaters based on MPEG-V standard. The key technologies of the 4-D broadcasting framework, required to provide sensory effect through home theaters consist of creating sensory effects synchronized with audiovisual contents, delivering the sensory effects with content to home theater devices, recognizing home devices for rendering sensory effects, and rendering contents through home theater system with connected sensory devices in a synchronized way. This paper proposes end-to-end technology required, in addition to the conventional broadcasting framework, based on international standard of MPEG-V, specifically Part 2 to describe capabilities of the home sensory devices, Part 3 to provide contents with sensory effects, and Part 5 to command the sensory devices among other parts of MPEG-V standard. © 2012 Elsevier B.V. All rights reserved. Source

Hong Y.J.,Sejong University | Yang J.W.,Pohang University of Science and Technology | Lee W.H.,Konkuk University | Ruoff R.S.,University of Texas at Austin | And 2 more authors.
Advanced Materials | Year: 2013

Van der Waals (vdW) epitaxial double heterostructures have been fabricated by vdW epitaxy of InAs nanostructures on both sides of graphene. InAs nanostructures diametrically form on/underneath graphene exclusively along As-polar direction, indicating polarity inversion of the double heterostructures. First-principles and density functional calculations demonstrate how and why InAs easily form to be double heterostructures with polarity inversion. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Jeong S.-W.,Kunsan National University | An Y.-J.,Konkuk University
Environmental Monitoring and Assessment | Year: 2012

The Korean government recently proposed expanding the number of soil-quality standards to 30 by 2015. The objectives of our study were to construct a reasonable protocol for screening priority soil contaminants for inclusion in the planned soil quality standard expansion. The chemical ranking system of soil pollution substances (CROSS) was first developed to serve as an analytical tool in chemical scoring and ranking of possible soil pollution substances. CROSS incorporates important parameters commonly used in several previous chemical ranking and scoring systems and the new soil pollution parameters. CROSS uses soil-related parameters in its algorithm, including information related to the soil environment, such as soil ecotoxicological data, the soil toxic release inventory (TRI), and soil partitioning coefficients. Soil TRI and monitoring data were incorporated as local specific parameters. In addition, CROSS scores the transportability of chemicals in soil because soil contamination may result in groundwater contamination. Dermal toxicity was used in CROSS only to consider contact with soil. CROSS uses a certainty score to incorporate data uncertainty. CROSS scores the importance of each candidate substance and assigns rankings on the basis of total scores. Cadmium was the most highly ranked. Generally, metals were ranked higher than other substances. Pentachlorophenol, phenol, dieldrin, and methyl tert-butyl ether were ranked the highest among chlorinated compounds, aromatic compounds, pesticides, and others, respectively. The priority substance list generated from CROSS will be used in selecting substances for possible inclusion in the Korean soil quality standard expansion; it will also provide important information for designing a soil-environment management scheme. © Springer Science+Business Media B.V. 2011. Source

Kang B.,Pohang University of Science and Technology | Lim S.,Pohang University of Science and Technology | Lee W.H.,Konkuk University | Jo S.B.,Pohang University of Science and Technology | Cho K.,Pohang University of Science and Technology
Advanced Materials | Year: 2013

RGO electrodes with work functions that can be widely tuned using direct surface functionalization are demonstrated by self-assembled monolayers anchored onto the surfaces of the RGO electrodes, which can remarkably enhance the device performance of organic field-effect transistors. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Kadam A.A.,Shivaji University | Telke A.A.,Gyeongsang National University | Jagtap S.S.,Konkuk University | Govindwar S.P.,Shivaji University
Journal of Hazardous Materials | Year: 2011

The objective of this study was to develop consortium using Pseudomonas sp. SUK1 and Aspergillus ochraceus NCIM-1146 to decolorize adsorbed dyes from textile effluent wastewater under solid state fermentation. Among various agricultural wastes rice bran showed dye adsorption up to 90, 62 and 80% from textile dye reactive navy blue HE2R (RNB HE2R) solution, mixture of textile dyes and textile industry wastewater, respectively. Pseudomonas sp. SUK1 and A. ochraceus NCIM-1146 showed 62 and 38% decolorization of RNB HE2R adsorbed on rice bran in 24. h under solid state fermentation. However, the consortium of Pseudomonas sp. SUK1 and A. ochraceus NCIM-1146 (consortium-PA) showed 80% decolorization in 24. h. The consortium-PA showed effective ADMI removal ratio of adsorbed dyes from textile industry wastewater (77%), mixture of textile dyes (82%) and chemical precipitate of textile dye effluent (CPTDE) (86%). Secretion of extracellular enzymes such as laccase, azoreductase, tyrosinase and NADH-DCIP reductase and their significant induction in the presence of adsorbed dye suggests their role in the decolorization of RNB HE2R. GCMS and HPLC analysis of product suggests the different fates of biodegradation of RNB HE2R when used Pseudomonas sp. SUK1, A. ochraceus NCIM-1146 and consortium PA. © 2011 Elsevier B.V. Source

Lee S.-Y.,Konkuk University
Journal of Gastroenterology and Hepatology (Australia) | Year: 2012

Since the discovery of Helicobacter pylori in 1982, the development of several treatment guidelines has allowed a consensus on the indications for H. pylori eradication. Beyond these currently accepted indications, including various upper gastrointestinal disorders and extragastric diseases, a significant amount of new information regarding H. pylori eradication is emerging. Certain types of acute gastritis, such as nodular gastritis, hypertrophic gastritis, Ménétrier's disease, hemorrhagic gastritis, and granulomatous gastritis are reversible after H. pylori eradication. Further, for chronic gastritis, closed-type atrophic gastritis and complete-type intestinal metaplasia appear to be more reversible after H. pylori eradication than open-type atrophic gastritis and incomplete-type intestinal metaplasia. Eradication can also be considered in subjects younger than 40years who have a family history of gastric cancer and in subjects with long-term medications that might lead to bleeding (antiplatelet agents) or atrophy (proton pump inhibitors). Emerging evidence indicates that H. pylori eradication could be an effective treatment for some extragastric diseases that are unresponsive to conventional therapy. In such conditions, routine screening for eradication of H. pylori has not previously been recommended; a "test-and-treat" approach is suggested in the aforementioned situations. Given that H. pylori eradication is effective when the gastritis is reversible, future indications should be expanded to include acute gastric lesions that show marked improvement upon H. pylori eradication rather than just focusing on chronic gastric lesions. Future indications for H. pylori eradication should focus more on reversible lesions before preneoplastic conditions develop. © 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd. Source

Cheung K.,National Tsing Hua University | Cheung K.,Konkuk University | Lu C.-T.,National Tsing Hua University | Yuan T.-C.,Academia Sinica, Taiwan
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Motivated by the excess in the diphoton production rate of the Higgs boson at the Large Hadron Collider (LHC), we investigate the possibility that one of the CP-even Higgs bosons of the extra U(1) extended minimal supersymmetric standard model can give a consistent result. We scan the parameter space for a standard-model-like Higgs boson such that the mass is in the range of 124-127 GeV and the production rate σB of the WW*, ZZ* modes is consistent with the standard model (SM) values, while that of γγ is enhanced relative to the SM value. We find that the SM-like Higgs boson is mostly the lightest CP-even Higgs boson and it has a strong mixing with the second lightest one, which is largely singletlike. The implications on Zγ production rate and properties of the other Higgs bosons are also studied. © 2013 American Physical Society. Source

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

Current data on the signal strengths and angular spectrum of the 125.5 GeV Higgs boson still allow a CP-mixed state, namely, the pseudoscalar coupling to the top quark can be as sizable as the scalar coupling: Cu S ≈Cu P =1/2. CP violation can then arise and manifest in sizable electric dipole moments (EDMs). In the framework of two-Higgs-doublet models, we not only update the Higgs precision (Higgcision) study on the couplings with the most updated Higgs signal strength data, but also compute all the Higgs-mediated contributions from the 125.5 GeV Higgs boson to the EDMs, and confront the allowed parameter space against the existing constraints from the EDM measurements of Thallium, neutron, Mercury, and Thorium monoxide. We found that the combined EDM constraints restrict the pseudoscalar coupling to be less than about 10-2, unless there are contributions from other Higgs bosons, supersymmetric particles, or other exotic particles that delicately cancel the current Higgs-mediated contributions. © 2014 The Author(s). Source

Dong-Soon I.M.,Pusan National University | Seung-Yeol N.A.H.,Konkuk University
Acta Pharmacologica Sinica | Year: 2013

Ginseng, the root of Panax ginseng, has been used in traditional Chinese medicine as a tonic herb that provides many beneficial effects. Pharmacologic studies in the last decades have shown that ginsenosides (ginseng saponins) are primarily responsible for the actions of ginseng. However, the effects of ginseng are not fully explained by ginsenosides. Recently, another class of active ingredients called gintonin was identified. Gintonin is a complex of glycosylated ginseng proteins containing lysophosphatidic acids (LPAs) that are the intracellular lipid mitogenic mediator. Gintonin specifically and potently activates the G protein-coupled receptors (GPCRs) for LPA. Thus, the actions of ginseng are now also linked to LPA and its GPCRs. This linkage opens new dimensions for ginseng pharmacology and LPA therapeutics. In the present review, we evaluate the pharmacology of ginseng with the traditional viewpoint of Yin and Yang components. Furthermore, we will compare ginsenoside and gintonin based on the modern view of molecular pharmacology in terms of ion channels and GPCRs. © 2013 CPS and SIMM. Source

Lim N.,Korea University | Cho N.,Korea University | Paek S.,Korea University | Kim C.,Konkuk University | And 2 more authors.
Chemistry of Materials | Year: 2014

High-performance organic semiconductors based on an electron-rich alkylsilylethynyl benzodithiophene (TIPSBDT) core were newly synthesized and characterized for use in solution-processed small-molecule organic solar cells. The rigid and extended π-conjugation of the TIPSBDT motifs facilitates intramolecular charge transfer and intermolecular π-π packing interactions of semiconducting small molecules in the BHJ film enhanced by processing additives and induces deep HOMO levels producing high open-circuit voltage of ∼1.0 V, exhibiting notable power conversion efficiency of 5.84% from a bulk-heterojunction film with PC61BM. © 2014 American Chemical Society. Source

Tahir M.N.,Konkuk University | Lee Y.,Seoul National University
Food Chemistry | Year: 2013

β-Cyclodextrin (β-CD) was converted into β-CD-N3 by chemical modification and subsequently attached covalently on glass surface by click reaction. Functionalised glass surface was characterised by static water contact angle and X-ray photoelectron spectroscopy (XPS). Both techniques show that β-CD was successfully attached on glass surface. β-CD on solid surface was used to make a complexation with cholesterol to remove it from milk. 69 ± 1% cholesterol was reduced in 4 h at 25 °C and 170 rpm. The same surface was used repeatedly for eight cycles and it maintained its efficiency, with 68 ± 2% cholesterol reduction. Modified glass surface showed almost no degradation as confirmed from XPS analysis after eight cycles of repeated use in cholesterol reduction experiments. The high efficiency and stability of functional monolayer was attributed to its specific structure with relatively low number of functional groups and longer spacer chain length to providing higher flexibility to β-CD molecules. © 2013 Elsevier Ltd. All rights reserved. Source

Yoon J.-R.,Veterans Health Service Medical Center | Oh K.-J.,Konkuk University | Wang J.H.,Sungkyunkwan University | Yang J.-H.,Veterans Health Service Medical Center
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2015

Purpose: In vivo comparative gap measurements were performed in three different patella positions (reduced, subluxated and everted) using offset-type-force-controlled-spreader-system. Methods: Prospectively, 50 knees were operated by total knee arthroplasty using a navigation-assisted gap-balancing technique. The offset-type-force-controlled-spreader-system was used for gap measurements. This commercially available instrument allows controllable tension in patella-reduced position. The mediolateral gaps of knee extension (0°) and flexion (90°) angle were recorded in three different patella positions; reduced, subluxated and everted. Any gap differences of more than 3 mm were considered as a meaningful difference. Correlation between the difference with the demographic data, preoperative radiologic alignment and intraoperative data was analysed. For statistical analysis, ANOVA and Pearson’s correlation test were used. Results: The gaps in patella eversion demonstrated smaller gaps both in knee extension and flexion position compared to the gaps of patella reduction position. The amount of decreased gaps was more definite in knee flexion position. Statistically significant difference was observed for the lateral gap of patella eversion compared to gap of patella reduction in knee flexion position (p < 0.05). There were notable cases of variability in knee flexion position. Significant portion of 12 (24 %) knees of patella subluxation and 33 (66 %) knees of patella evertion demonstrated either increased or decreased gaps in knee flexion position compared to the gaps of patella reduction position. Conclusion: The gaps in patella eversion demonstrated smaller gaps both in knee extension and flexion position compared to the gaps of patella reduction position. The amount of decreased gaps was more definite in knee flexion position. Therefore, the intraoperative patellar positioning has influence on the measurement of the joint gap. Keeping the patella in reduced position is important during gap balancing. Level of evidence: I. © 2014, Springer-Verlag Berlin Heidelberg. Source

Kim H.,Seoul National University | Lee S.-A.,Seoul National University | Kim D.-W.,Seoul National University | Lee S.-H.,Konkuk University | Kim B.-J.,Seoul National University
PLoS ONE | Year: 2013

Molecular mechanisms related to occult hepatitis B virus (HBV) infection, particularly those based on genotype C infection, have rarely been determined thus far in the ongoing efforts to determine infection mechanisms. Therefore, we aim to elucidate the mutation patterns in the surface open reading frame (S ORF) underlying occult infections of HBV genotype C in the present study. Nested PCRs were applied to 624 HBV surface antigen (HBsAg) negative Korean subjects. Cloning and sequencing of the S ORF gene was applied to 41 occult cases and 40 control chronic carriers. Forty-one (6.6%) of the 624 Korean adults with HBsAg-negative serostatus were found to be positive for DNA according to nested PCR tests. Mutation frequencies in the three regions labeled here as preS1, preS2, and S were significantly higher in the occult subjects compared to the carriers in all cases. A total of two types of deletions, preS1 deletions in the start codon and preS2 deletions as well as nine types of point mutations were significantly implicated in the occult infection cases. Mutations within the "a" determinant region in HBsAg were found more frequently in the occult subjects than in the carriers. Mutations leading to premature termination of S ORF were found in 16 occult subjects (39.0%) but only in one subject from among the carriers (2.5%). In conclusion, our data suggest that preS deletions, the premature termination of S ORF, and "a" determinant mutations are associated with occult infections of HBV genotype C among a HBsAg-negative population. The novel mutation patterns related to occult infection introduced in the present study can help to broaden our understanding of HBV occult infections. © 2013 Kim et al. Source

Lee K.W.,Konkuk University | Lee K.W.,Seoul National University | Bode A.M.,University of Minnesota | Dong Z.,University of Minnesota
Nature Reviews Cancer | Year: 2011

Although successful for a limited number of tumour types, the efficacy of cancer therapies, especially for late-stage disease, remains poor overall. Many have argued that this could be avoided by focusing on cancer prevention, which has now entered the arena of targeted therapies. During the process of identifying preventive agents, dietary phytochemicals, which are thought to be safe for human use, have emerged as modulators of key cellular signalling pathways. The task now is to understand how these chemicals perturb these pathways by modelling their interactions with their target proteins. © 2011 Macmillan Publishers Limited. All rights reserved. Source

Kang B.,Pohang University of Science and Technology | Lee W.H.,Konkuk University | Cho K.,Pohang University of Science and Technology
ACS Applied Materials and Interfaces | Year: 2013

Recent progress in organic field-effect transistor (OFET) printing processes is reviewed, and a perspective on the future of the field is discussed. The principles underlying the OFET printing techniques are introduced according to two categories: direct write printing and transfer printing. A comprehensive overview of the use of printing techniques in OFET production processes is also provided. Considerations for improving OFET device performance using printing processes are explored. Prior to OFET commercialization, the OFET printing techniques must satisfy several requirements, as discussed here. © 2013 American Chemical Society. Source

Sohn K.,Konkuk University
Annals of Human Biology | Year: 2015

Background: A group of researchers has argued that sexual stature dimorphism (SSD) can serve as an indicator of living standards. This argument is based on evidence that boys’ physical growth is more sensitive to environmental conditions than girls’ physical growth. Because Korea's economic growth in the second half of the 20th century was unprecedentedly rapid, according to their logic, it is likely to see an increasing trend in SSD. Aim: We aimed to determine whether SSD can serve as an accurate indicator of living standards for a population that would exhibit a pronounced trend in SSD, providing that the logic for use of SSD is correct. Subjects and methods: We employed nationally representative Korean men born in 1941–1990 (n = 17 268) and women born in 1941–1991 (n = 22 543) and estimated mean heights by sex and birth years. We then calculated SSD values and charted the trend. Results: Although male height increased faster than female height, the SSD trend was flat for the pooled observations and for sub-groups by socioeconomic status. Conclusion: These results cast doubt on the argument for using SSD as an indicator of living standards. © 2015 Taylor & Francis. Source

Kim K.J.,Konkuk University | Lim K.-Y.,University of Seoul | Kim Y.-W.,University of Seoul
Journal of the American Ceramic Society | Year: 2011

The effects of the yttrium nitrate (YN) content on nitrogen doping and the electrical resistivity of SiC ceramics were investigated. The YN was found to be an effective sintering additive for the full densification of SiC ceramics by hot-pressing. The hot-pressed bulk samples were identified as polycrystalline zincblende β-SiC with a small amount of α-SiC and Y2O 3 crystallites. The SiC grains contained nitrogen (N) as an impurity that contributed to the decrease in electrical resistivity of the samples. An optimum YN composition exists for which the N concentration is maximized to give the lowest resistivity. The SiC samples exhibited a resistivity as low as ∼10-3 ωcm and a carrier density of ∼1020 cm-3, which was excited from the N donor levels. The resistivity of the samples was maintained in the same order of magnitude over a wide temperature range (4-300 K). © 2011 The American Ceramic Society. Source

Choi S.H.,Korea University | Lee J.-K.,Konkuk University | Kang Y.C.,Korea University
Nano Research | Year: 2015

The use of new three-dimensional (3D) porous graphene-metal oxide composite microspheres as an anode material for Li-ion batteries (LIBs) is first introduced here. 3D graphene microspheres are aggregates of individual hollow graphene nanospheres composed of graphene sheets. Metal oxide nanocrystals are uniformly distributed over the graphene surface of the microspheres. The 3D porous graphene-SnO2 microspheres are selected as the first target material for investigation because of their superior electrochemical properties. The 3D porous graphene-SnO2 and graphene microspheres and bare SnO2 powders deliver discharge capacities of 1,009, 196, and 52 mAh·g−1, respectively, after 500 cycles at a current density of 2 A·g−1. The 3D porous graphene-SnO2 microspheres exhibit uniquely low charge transfer resistances and high Li-ion diffusivities before and after cycling. © 2014, Tsinghua University Press and Springer-Verlag Berlin Heidelberg. Source

Sajib S.Z.K.,Kyung Hee University | Kim H.J.,Kyung Hee University | Kwon O.I.,Konkuk University | Woo E.J.,Kyung Hee University
Physics in Medicine and Biology | Year: 2012

Magnetic resonance electrical impedance tomography (MREIT) is a non-invasive technique for imaging the internal conductivity distribution in tissue within an MRI scanner, utilizing the magnetic flux density, which is introduced when a current is injected into the tissue from external electrodes. This magnetic flux alters the MRI signal, so that appropriate reconstruction can provide a map of the additional z-component of the magnetic field (B z) as well as the internal current density distribution that created it. To extract the internal electrical properties of the subject, including the conductivity and/or the current density distribution, MREIT techniques use the relationship between the external injection current and the z-component of the magnetic flux density B = (B x, B y, B z). The tissue studied typically contains defective regions, regions with a low MRI signal and/or low MRI signal-to-noise-ratio, due to the low density of nuclear magnetic resonance spins, short T 2 or T* 2 relaxation times, as well as regions with very low electrical conductivity, through which very little current traverses. These defective regions provide noisy B z data, which can severely degrade the overall reconstructed conductivity distribution. Injecting two independent currents through surface electrodes, this paper proposes a new direct method to reconstruct a regional absolute isotropic conductivity distribution in a region of interest (ROI) while avoiding the defective regions. First, the proposed method reconstructs the contrast of conductivity using the transversal J-substitution algorithm, which blocks the propagation of severe accumulated noise from the defective region to the ROI. Second, the proposed method reconstructs the regional projected current density using the relationships between the internal current density, which stems from a current injection on the surface, and the measured B z data. Combining the contrast conductivity distribution in the entire imaging slice and the reconstructed regional projected current density, we propose a direct non-iterative algorithm to reconstruct the absolute conductivity in the ROI. The numerical simulations in the presence of various degrees of noise, as well as a phantom MRI imaging experiment showed that the proposed method reconstructs the regional absolute conductivity in a ROI within a subject including the defective regions. In the simulation experiment, the relative L 2-mode errors of the reconstructed regional and global conductivities were 0.79 and 0.43, respectively, using a noise level of 50 db in the defective region. © 2012 Institute of Physics and Engineering in Medicine. Source

Kim C.-H.,Konkuk University | Kim M.-B.,Sungkyunkwan University | Ban J.H.,Sungkyunkwan University
Laryngoscope | Year: 2014

Objectives/Hypothesis The aim of this study was to characterize the clinical features and typical positional nystagmus in patients with persistent geotropic direction-changing positional nystagmus (DCPN) and address the possible pathophysiology of the disease. Furthermore, the proportion of light cupula among the patients showing geotropic DCPN was investigated to assume the incidence of light cupula in those patients. Study Design Prospective case series. Methods We conducted a prospective case series study in 19 patients with persistent geotropic DCPN. Positional nystagmus during the bow and lean test and the supine head roll test was analyzed using videonystagmography. Results All of the 19 patients showed persistent geotropic DCPN without latency. A null plane in which the nystagmus ceases was identified in all of 19 patients, and the intensity of nystagmus was stronger on one side in13 patients (68%) on supine head roll test. Overall, the affected side could be identified in 18 patients (95%). About 14.2% (19 of 134) of patients with geotropic DCPN could be diagnosed as having light cupula in the horizontal semicircular canal. Conclusions The patients with light cupula show persistent geotropic DCPN without latency. Affected side(s) can be determined by the direction and intensity of the characteristic positional nystagmus and the side of the null plane. The pathophysiology and treatment of light cupula still remain to be elucidated. Level of Evidence 4. Laryngoscope, 124:E15-E19, 2014 © 2013 The American Laryngological, Rhinological and Otological Society, Inc. Source

Lim M.,Konkuk University
International Journal of Software Engineering and its Applications | Year: 2015

We propose an improved version of our communication middleware for social networking services (CMSNS) designed to support the rapid development of a social networking service (SNS) application through simple application programming interfaces (APIs) and configuration options related to communication among users. With CMSNS, a developer can easily build the communication-related functions that are commonly required for SNS applications, including communication architecture management, user registration and authentication, event transmission, and SNS messages with friends. We improved the internal architecture of the proposed CMSNS to provide platform independence, save event size, use an event queue to efficiently process events, and adopt a model-view-controller (MVC) design pattern to separate the internal information from multiple event controller modules. © 2015 SERSC. Source

Park Y.M.,Johns Hopkins University | Park Y.M.,Konkuk University | Bochner B.S.,Johns Hopkins University
Allergy, Asthma and Immunology Research | Year: 2010

Eosinophilia is common feature of many disorders, including allergic diseases. There are many factors that influence the production, migration, survival and death of the eosinophil. Apoptosis is the most common form of physiological cell death and a necessary process to maintain but limit cell numbers in humans and other species. It has been directly demonstrated that eosinophil apoptosis is delayed in allergic inflammatory sites, and that this mechanism contributes to the expansion of eosinophil numbers within tissues. Among the proteins known to influence hematopoiesis and survival, expression of the cytokine interleukin-5 appears to be uniquely important and specific for eosinophils. In contrast, eosinophil death can result from withdrawal of survival factors, but also by activation of pro-apoptotic pathways via death factors. Recent observations suggest a role for cell surface death receptors and mitochondria in facilitating eosinophil apoptosis, although the mechanisms that trigger each of these death pathways remain incompletely delineated. Ultimately, the control of eosinophil apoptosis may someday become another therapeutic strategy for treating allergic diseases and other eosinophil-associated disorders. © Copyright The Korean Academy of Asthma, Allergy and Clinical Immunology • The Korean Academy of Pediatric Allergy and Respiratory Disease. Source

Kim S.-J.,Konkuk University
Korean Circulation Journal | Year: 2011

Heterotaxy is defined as an abnormality where the internal thoraco-abdominal organs demonstrate abnormal arrangement across the left-right axis of the body. This broad term includes patients with a wide variety of very complex cardiac lesions. Patients with heterotaxy can be stratified into the subsets of asplenia syndrome and polysplenia syndrome, or the subsets of heterotaxy with isomerism of the right atrial appendages and heterotaxy with isomerism of the left atrial appendages. Treatment of patients with isomerism is determined by the nature and severity of the associated cardiac and extracardiac lesions. Most cardiac operations for patients with isomerism are palliative in nature, since normal anatomy is rarely achieved and mortality rates remain high for patients with heterotaxy syndrome. Patients with left isomerism in general have less severe cardiac malformations man those with right isomerism and, hence, more chance of biventricular repair. For almost all patients with right isomerism, and for many with left isomerism, biventricular repair will not be feasible, and all palliative protocols are then staging procedures prior to a Fontan-type repair. Recent advances in medical management, and improvements in surgical techniques have resulted in improved survival for these patients, and the surgical outcomes are comparable to those with Fontan circulation irrespective of the presence or absence of heterotaxy. Copyright © 2011 The Korean Society of Cardiology. Source

Song J.-W.,Ewha Womans University | Jeon E.-Y.,Ewha Womans University | Song D.-H.,Ewha Womans University | Jang H.-Y.,Ewha Womans University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2013

A multistep enzyme catalysis was successfully implemented to produce long-chain α,ω-dicarboxylic and ω-hydroxycarboxylic acids from renewable fatty acids and plant oils. Sebacic acid as well as ω-hydroxynonanoic acid and ω-hydroxytridec-11-enoic acid were produced from oleic and ricinoleic acid. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Lim C.,Konkuk University | Ito H.,University of Tokyo
Technovation | Year: 2013

Although product innovation for unserved lower end mega markets in large developing countries has been recognized as an opportunity for improving the competitiveness of local firms, limited research has been conducted that explicitly explores how innovation capabilities can be built for these markets. This study investigates Tata Motors' Nano as an exploratory case of building innovation capabilities. This paper shows that the building of innovation capability could be achieved through creating a process that overcomes 'the deficiency problem' in generating radically cheap priced original products. The study's contribution to the literature is that it addresses issues of building local firms' innovation capabilities through creating original products for the unserved lower end market, in which advanced country firms have limited experience. Nano, as an unprecedented innovation in the automobile industry, reveals a path to building innovation capability that has not previously been observed. We show that detailed processes involved in generating an original product for the lower end market provide insights on the strategy in terms of target price setting, initiating innovation process overcoming 'the deficiency problem', and creation of complementary resources. © 2013 Elsevier Ltd. Source

Han S.,Konkuk University
International Journal of Innovative Computing, Information and Control | Year: 2012

In this paper, the finite impulse response (FIR) filter based on an exponential quadratic cost function is proposed for a stochastic discrete-time state space model. The joint probability density function of the current state and the external noises on the recent finite horizon is introduced and the corresponding expected value of the exponential quadratic cost function is minimized with respect to the current state. According to the sign of the scalar real parameter in the cost function, we have a risk averse or seeking criterion, from which the optimal FIR filter, called a risk sensitive FIR filter (RSFF), is derived. Being risk averse means that large weights are put on large estimation errors which are suppressed as much as possible. Being risk seeking means that large weights are put on moderate estimation errors. It is also shown via simulation that the proposed FIR filter has better performance than the conventional infinite impulse response (IIR) robust Kalman filter. © 2012 ICIC International. Source

Paeng S.-H.,Konkuk University
European Journal of Combinatorics | Year: 2012

We obtain upper bounds of diameter and volume for finite graphs by Ollivier's Ricci curvature. © 2012 Elsevier Ltd. Source

Hwan Ko J.,Seoul National University | Byun D.,Konkuk University
Computers and Structures | Year: 2010

Mid-frequency response analysis often faces computational difficulties when a conventional modal approach is used for a finite element linear system. In this paper, the computational burden is relieved by frequency sweep algorithm or mode acceleration method for a reduced-order system constructed by algebraic substructuring, a variant of model order reduction. The two methods are compared with the help of numerical experiments and their computational complexity. As demonstrated by the finite element simulations, in which proportional damping is assumed, of a turbo-prop aircraft and a ring resonator, the frequency sweep algorithm for reduced-order systems shows the best performance among all considered numerical solutions, including the conventional approach. © 2009 Elsevier Ltd. All rights reserved. Source

Pai J.,Yonsei University | Yoon T.,Yonsei University | Kim N.D.,New Drug Development Research Center Inc. | Lee I.-S.,Konkuk University | And 2 more authors.
Journal of the American Chemical Society | Year: 2012

A rapid and quantitative method to evaluate binding properties of hairpin RNAs to peptides using peptide microarrays has been developed. The microarray technology was shown to be a powerful tool for high-throughput analysis of RNA-peptide interactions by its application to profiling interactions between 111 peptides and six hairpin RNAs. The peptide microarrays were also employed to measure hundreds of dissociation constants (Kd) of RNA-peptide complexes. Our results reveal that both hydrophobic and hydrophilic faces of amphiphilic peptides are likely involved in interactions with RNAs. Furthermore, these results also show that most of the tested peptides bind hairpin RNAs with submicromolar Kd values. One of the peptides identified by using this method was found to have good inhibitory activity against TAR-Tat interactions in cells. Because of their great applicability to evaluation of nearly all types of RNA-peptide interactions, peptide microarrays are expected to serve as robust tools for rapid assessment of peptide-RNA interactions and development of peptide ligands against RNA targets. © 2012 American Chemical Society. Source

Kim J.H.,Korea University | Kim D.-W.,Konkuk University | Kim J.B.,Korea University | Suh S.-Il.,Korea University | Koh S.-B.,Korea University
Human Brain Mapping | Year: 2015

Alteration of basal ganglia-thalamocortical circuit has been hypothesized to play a role in the pathophysiology underlying paroxysmal kinesigenic dyskinesia (PKD). We investigated macrostructural and microstructural changes in PKD patients using structural and diffusion tensor magnetic resonance imaging (MRI) analyses. Twenty-five patients with idiopathic PKD and 25 control subjects were prospectively studied on a 3T magnetic resonance (MR) scanner. Cortical thickness analysis was used to evaluate cortical gray matter (GM) changes, and automated volumetry and shape analysis were used to assess volume changes and shape deformation of the subcortical GM structures, respectively. Tract-based spatial statistics (TBSS) was used to evaluate white matter integrity changes in a whole-brain manner, and region-of-interest (ROI) analysis of diffusion tensor metrics was performed in subcortical GM structures. Compared to controls, PKD patients exhibited a reduction in volume of bilateral thalami and regional shape deformation mainly localized to the anterior and medial aspects of bilateral thalami. TBSS revealed an increase in fractional anisotropy (FA) of bilateral thalami and right anterior thalamic radiation in patients relative to controls. ROI analysis also showed an increase in FA of bilateral thalami in patients compared to controls. We have shown evidence for thalamic abnormalities of volume reduction, regional shape deformation, and increased FA in patients with PKD. Our novel findings of concomitant macrostructural and microstructural abnormalities in the thalamus lend further support to previous observations indicating causal relationship between a preferential lesion in the thalamus and development of PKD, thus providing neuroanatomical basis for the involvement of thalamus within the basal ganglia-thalamocortical pathway in PKD. Hum Brain Mapp 36:1429-1441, 2015. © 2014 Wiley Periodicals, Inc. Source

Liu M.,Rice University | Artyukhov V.I.,Rice University | Lee H.,Rice University | Lee H.,Konkuk University | And 2 more authors.
ACS Nano | Year: 2013

We report an extensive study of the properties of carbyne using first-principles calculations. We investigate carbyne's mechanical response to tension, bending, and torsion deformations. Under tension, carbyne is about twice as stiff as the stiffest known materials and has an unrivaled specific strength of up to 7.5 × 107 N·m/kg, requiring a force of ∼10 nN to break a single atomic chain. Carbyne has a fairly large room-temperature persistence length of about 14 nm. Surprisingly, the torsional stiffness of carbyne can be zero but can be "switched on" by appropriate functional groups at the ends. Further, under appropriate termination, carbyne can be switched into a magnetic semiconductor state by mechanical twisting. We reconstruct the equivalent continuum elasticity representation, providing the full set of elastic moduli for carbyne, showing its extreme mechanical performance (e.g., a nominal Young's modulus of 32.7 TPa with an effective mechanical thickness of 0.772 Å). We also find an interesting coupling between strain and band gap of carbyne, which is strongly increased under tension, from 2.6 to 4.7 eV under a 10% strain. Finally, we study the performance of carbyne as a nanoscale electrical cable and estimate its chemical stability against self-aggregation, finding an activation barrier of 0.6 eV for the carbyne-carbyne cross-linking reaction and an equilibrium cross-link density for two parallel carbyne chains of 1 cross-link per 17 C atoms (2.2 nm). © 2013 American Chemical Society. Source

Choi S.H.,Korea University | Ko Y.N.,Korea University | Lee J.-K.,Konkuk University | Kang Y.C.,Korea University
Advanced Functional Materials | Year: 2015

A novel anode material for sodium-ion batteries consisting of 3D graphene microspheres divided into several tens of uniform nanospheres coated with few-layered MoS2 by a one-pot spray pyrolysis process is prepared. The first discharge/charge capacities of the composite microspheres are 797 and 573 mA h g-1 at a current density of 0.2 A g-1. The 600th discharge capacity of the composite microspheres at a current density of 1.5 A g-1 is 322 mA h g-1. The Coulombic efficiency during the 600 cycles is as high as 99.98%. The outstanding Na ion storage properties of the 3D MoS2-graphene composite microspheres may be attributed to the reduced stacking of the MoS2 layers and to the 3D structure of the porous graphene microspheres. The reduced stacking of the MoS2 layers relaxes the strain and lowers the barrier for Na+ insertion. The empty nanospheres of the graphene offer voids for volume expansion and pathways for fast electron transfer during repeated cycling. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Son Y.-S.,Harvard University | Kim J.-C.,Konkuk University
Chemical Engineering Journal | Year: 2015

Influential factors were investigated to increase decomposition efficiencies of sulfur compounds using an electron beam. Their initial concentrations, different background gases, and relative humidity were of main concern as the factors. Decomposition efficiency of H2S by primary electrons was lower than those of CH3SH, DMS, and DMDS containing one or two CH3 groups. The G-values increased as their initial concentrations increased and the adsorbed dose decreased. Removal efficiencies were highest for H2S and CH3SH in the simultaneous presence of N and O radicals. In contrast, reactions with the O radical were the most effective when DMS and DMDS were irradiated by electron beam under different background gases. Adding water vapor to the reactors resulted in the increase of decomposition efficiency. © 2014 Elsevier B.V. Source

Shin J.H.,Konkuk University
Geotechnique | Year: 2010

One of the main issues in tunnel maintenance is the hydraulic deterioration of the drainage system. In this study, simple methods to evaluate pore water pressures on existing tunnels were proposed. The methods involve an indirect and non-destructive approach while providing a convenient and easy method to evaluate the residual pore water pressure on the lining. Source

Jang L.-C.,Konkuk University
Mathematical Problems in Engineering | Year: 2010

We define the multiple generalized ω-Genocchi polynomials. By using fermionic p-adic invariant integrals, we derive some identities on these generalized ω-Genocchi polynomials, for example, fermionic p-adic integral representation, Witt's type formula, explicit formula, multiplication formula, and recurrence formula for these ω-Genocchi polynomials. Copyright © 2010 Lee-Chae Jang. Source

Kim J.,Konkuk University
International Journal of Technology, Policy and Management | Year: 2015

The theory of flexible specialisation has been offering a challenging alternative to mass production system since its debut. Despite the attractiveness of the theory, practical applicability of the theoretical content has been weak. As time passes by, however, new momentum has been building up from the robotics and its related technology development, which can really open up the possibilities for flexible specialisation. Especially the advent of ageing society can be an impetus to change the industrial paradigm, due to labour shortage. This paper, noting the symptoms of change, has endeavoured with empirical data of Korea to see which industrial sectors are likely to start up this industrial change in the future. Copyright © 2015 Inderscience Enterprises Ltd. Source

Sul I.H.,Konkuk University
International Journal of Clothing Science and Technology | Year: 2010

Purpose: The purpose of this paper is to develop a new and simple methodology for fabric collision detection and response. Design/methodology/approach: A 3D triangle-to-triangle collision problem was converted to simple 2D point-in-triangle problem using pre-computed 4×4 transformation matrices. The object space was partitioned using voxels to find easily collision pair triangles. k-DOP was used to find inter-pattern collisions. Findings: Complex 3D collision detection problem is solved by simple matrix operations. Voxel-based space partitioning and k-DOP-based hierarchical methods are successfully applied to garment simulation. Originality/value: This paper shows that the collision matrix method can cover from triangle-to-point to triangle-to-triangle collision with mathematical validity and can be simply implemented in garment simulation. © Emerald Group Publishing Limited. Source

Liu D.,U.S. National Institute on Aging | Pitta M.,U.S. National Institute on Aging | Jiang H.,U.S. National Institute on Aging | Lee J.-H.,Konkuk University | And 4 more authors.
Neurobiology of Aging | Year: 2013

Impaired brain energy metabolism and oxidative stress are implicated in cognitive decline and the pathologic accumulations of amyloid β-peptide (Aβ) and hyperphosphorylated tau in Alzheimer's disease (AD). To determine whether improving brain energy metabolism will forestall disease progress in AD, the impact of the β-nicotinamide adenine dinucleotide precursor nicotinamide on brain cell mitochondrial function and macroautophagy, bioenergetics-related signaling, and cognitive performance were studied in cultured neurons and in a mouse model of AD. Oxidative stress resulted in decreased mitochondrial mass, mitochondrial degeneration, and autophagosome accumulation in neurons. Nicotinamide preserved mitochondrial integrity and autophagy function, and reduced neuronal vulnerability to oxidative/metabolic insults and Aβ toxicity. β-Nicotinamide adenine dinucleotide biosynthesis, autophagy, and phosphatidylinositol-3-kinase signaling were required for the neuroprotective action of nicotinamide. Treatment of 3xTgAD mice with nicotinamide for 8 months resulted in improved cognitive performance, and reduced Aβ and hyperphosphorylated tau pathologies in hippocampus and cerebral cortex. Nicotinamide treatment preserved mitochondrial integrity, and improved autophagy-lysosome procession by enhancing lysosome/autolysosome acidification to reduce autophagosome accumulation. Treatment of 3xTgAD mice with nicotinamide resulted in elevated levels of activated neuroplasticity-related kinases (protein kinase B [Akt] and extracellular signal-regulated kinases) and the transcription factor cyclic adenosine monophosphate (AMP) response element-binding protein in the hippocampus and cerebral cortex. Thus, nicotinamide suppresses AD pathology and cognitive decline in a mouse model of AD by a mechanism involving improved brain bioenergetics with preserved functionality of mitochondria and the autophagy system. © 2013 . Source

Cheon Y.K.,Konkuk University
Journal of Neurogastroenterology and Motility | Year: 2012

To date, endoscopic manometry is the best method for evaluating the function of the sphincter. Sphincter of Oddi manometry (SOM) remains the gold standard to correctly diagnose the sphincter of Oddi dysfunction (SOD) and stratify therapy. Several dynamic abnormalities relating to the intensity, frequency, and propagation of sphincter contractions have been described. However, their clinical use generally has been abandoned in favor of basal sphincter pressure alone, because this measurement is stable over time, and has stronger interobserver reliablility, reproducibility on repeating testing, and is associated with the responsiveness to therapy. A significant elevated risk of pancreatitis was attributed to the technique. The risk of pancreatitits associated with manometric evaluation of the pancreatic sphincter is markedly reduced when manometry is performed with continous aspiration from the pancreatic duct via one of the 3 catheter lumens. This section reviews indications, conscious sedative drugs, techniques, and the appropriate interpretations of SOM. © 2012 The Korean Society of Neurogastroenterology and Motility. Source

Paeng S.-H.,Konkuk University
Physica A: Statistical Mechanics and its Applications | Year: 2015

Currency can be considered as a ruler for values of commodities. Then the price is the measured value by the ruler. We can suppose that inflation and variation of exchange rate are caused by variation of the scale of the ruler. In geometry, variation of the scale means that the metric is time-dependent. The conjugate heat equation is the modified heat equation which satisfies the heat conservation law for the time-dependent metric space. We propose a new model of stock prices by using the stochastic process whose transition probability is determined by the kernel of the conjugate heat equation. Our model of stock prices shows how the volatility term is affected by inflation and exchange rate. This model modifies the Black-Scholes equation in light of inflation and exchange rate. © 2014 Elsevier B.V. Source

Nam M.-H.,Konkuk University | Nha I.-S.,Yonsei University
History of Mechanism and Machine Science | Year: 2015

The fourth monarch King Sejong (r. 1418-50) of the Joseon dynasty (1392-1910) launched a program to equip the Royal Observatory (Ganui-dae) during 1432-38 to establish Neo-Confucian political ideology, and to promote agriculture and social culture. The project was focused on adjusting the Season-granting system fitting to the latitude of Hanyang (now Seoul). And it was also aimed on making observational equipments for calculating astronomical constants fitting to Hanyang as well as timekeeping devices for civil services. Sejong constructed five kinds of astronomical equipment in the main palace grounds: the Simplified Armilla and its platform, the forty-cheok -high (828 cm) Template and Bronze Tall Gnomon with Shadow Aligner, the Direction-determining Square Table and the Water-operated Armillary Sphere and Celestial Globe. To do this, the Korean version of the Chinese Zhou Foot-Rule (Ju-cheok) which is equivalent to 20.7 cm employed as standard measure for scaling. In 1442, the first Joseon native calendar Calculations on the Celestial Motions of Seven Regulators (Chiljeong-san) came into use. Moreover, the Rain-gauge (Cheugu-gi), the oldest known philosophical instrument for measuring precipitation, was invented at this time and put into use. The new system of observing the rule of heaven enabled the king to implement the ruling by Neo-Confucian rites and virtues following the practices of the Yao and Shun. The Observatory provided the momentum to lay the groundwork for scientific and social norm in fifteenth century Korea. Sejong's achievements not only helped to advance East Asian astronomy, but also set a milestone in the world history of astronomy. © 2015 Springer Science+Business Media Dordrecht. Source

Nam M.-H.,Konkuk University
History of Mechanism and Machine Science | Year: 2014

Yeong-sil Jang (called Jang Yeong-sil in the Korean style, Unknown) was a Korean inventor and mechanical engineer who served as chief court engineer under King Sejong of the Joseon dynasty (AD 1392-1910). He made two Striking Clepsydras (Jagyeong-nu) in the course of equipping the Royal Observatory in AD 1432-38. He invented liquid-driven discrete ball-falling mechanisms and ball-driven discrete motion control mechanisms for operating dual-time-announcing devices, and applied these towards making the Striking Palace Clepsydra. He developed the mechanisms and employed them to make a functional astronomical clock, the Striking Heavenly Clepsydra, which worked in conjunction with a water-powered wheel drive. The clepsydra was a standard timekeeper capable of announcing twelve double-hours with a bell simultaneous with a visual display indicating the current time. Five night-watches and their twenty-five points could also be announced by way of a drum and gong without human involvement. The stories of his works are told in the Annals of Sejong issued in 1454 and are supplemented by accounts in the dynastic documents afterwards. His innovations on mechanism design led to subsequent astronomical clocks from the seventeenth century onwards in Korea. Not only did he assimilate the techniques of his Korean, Chinese and Islamic predecessors, but was also creative and innovative in the history of mechanism and machine design. © 2014 Springer Science+Business Media Dordrecht. Source

Lee Y.-M.,Konkuk University
Microwave and Optical Technology Letters | Year: 2016

This article is a study of design of the rain sensor using a coaxial cavity resonator. We made some ranges of resonant frequencies by controlling the input voltage of the oscillator which will be mainly resonated in the coaxial cavity resonator. First, we made the coaxial cavity resonator by simulating the resonator structure with the proposed size and we expect the resonant frequency with the simulation and then we decide the voltage control oscillator (VCO) by the result. Second, we made the coaxial cavity resonator with the simulation result and water droplets detecting sensor circuit which is composed of voltage controlled oscillator, radio frequency (RF) Detector, and microcontroller unit (MCU). VCO makes the frequency which is resonated in the resonator, and RF Detector gets the RF signal and informs it to the analog voltage, and MCU gets the analog voltage and then changes it to the digital signal. We decided the size of the resonator with inner conductor 5 mm, outer conductor 14 mm, the height of the resonator 9.5 mm, and the height of the glass 6 mm from the simulated result. The simulated resonant frequencies is 3.09 [GHz], and we made the VCO frequency has ranges from 2.56-3.2 [GHz]. The measured resonant frequency is 2.97 [GHz] and the return loss is under -8.4 dB at the center frequency. When the water dropped on the glass of the resonator, the voltage has changed from 690 to 145 mV. It shows the proposed water sensor can detect the water variation by the variation of the resonant frequency of the resonator. © 2016 Wiley Periodicals, Inc. Source

Lee S.-H.,Jeju National University | Lee S.-H.,Konkuk University | Jeon Y.-J.,Jeju National University
Fitoterapia | Year: 2013

Marine algae are popular and abundant food ingredients mainly in Asian countries, and also well known for their health beneficial effects due to the presence of biologically active components. The marine algae have been studied for biologically active components and phlorotannins, marine polyphenols are among them. Among marine algae, brown algae have extensively studied for their potential anti-diabetic activities. Majority of the investigations on phlorotannins derived from brown algae have exhibited their various anti-diabetic mechanisms such as α-glucosidase and α-amylase inhibitory effect, glucose uptake effect in skeletal muscle, protein tyrosine phosphatase 1B (PTP 1B) enzyme inhibition, improvement of insulin sensitivity in type 2 diabetic db/db mice, and protective effect against diabetes complication. In this review, we have made an attempt to discuss the various anti-diabetic mechanisms associated with phlorotannins from brown algae that are confined to in vitro and in vivo. © 2013 Elsevier B.V. All rights reserved. Source

Choi Y.J.,Konkuk University
Clinical and molecular hepatology | Year: 2014

BACKGROUND/AIMS: A revised classification system for renal dysfunction in patients with cirrhosis was proposed by the Acute Dialysis Quality Initiative and the International Ascites Club Working Group in 2011. The aim of this study was to determine the prevalence of renal dysfunction according to the criteria in this proposal.METHODS: The medical records of cirrhotic patients who were admitted to Konkuk University Hospital between 2006 and 2010 were reviewed retrospectively. The data obtained at first admission were collected. Acute kidney injury (AKI) and chronic kidney disease (CKD) were defined using the proposed diagnostic criteria of kidney dysfunction in cirrhosis.RESULTS: Six hundred and forty-three patients were admitted, of whom 190 (29.5%), 273 (42.5%), and 180 (28.0%) were Child-Pugh class A, B, and C, respectively. Eighty-three patients (12.9%) were diagnosed with AKI, the most common cause for which was dehydration (30 patients). Three patients had hepatorenal syndrome type 1 and 26 patients had prerenal-type AKI caused by volume deficiency after variceal bleeding. In addition, 22 patients (3.4%) were diagnosed with CKD, 1 patient with hepatorenal syndrome type 2, and 3 patients (0.5%) with AKI on CKD.CONCLUSIONS: Both AKI and CKD are common among hospitalized cirrhotic patients, and often occur simultaneously (16.8%). The most common type of renal dysfunction was AKI (12.9%). Diagnosis of type 2 hepatorenal syndrome remains difficult. A prospective cohort study is warranted to evaluate the clinical course in cirrhotic patients with renal dysfunction. Source

Yoo J.-M.,Chungnam National University | Park E.S.,Konkuk University | Kim M.R.,Chungnam National University | Sok D.-E.,Chungnam National University
Lipids | Year: 2013

Recently, endogenous N-acyl dopamines have been found to show anti-inflammatory and immunomodulatory activities. However, the effect of the N-acyl dopamines on allergic responses was not reported. In this study, we investigated whether N-acyl dopamines might inhibit immunoglobulin E-mediated degranulation in RBL-2H3 cells. When RBL-2H3 cells were exposed to palmitoyl dopamine (NP-DA), oleoyl dopamine (NO-DA) or arachidonoyl dopamine (NA-DA) at micromolar levels, all these compounds significantly inhibited the release of β-hexosaminidase, a marker of degranulation, as well as tumor necrosis factor (TNF)-α. In comparison, NP-DA, potently suppressing the release of β-hexosaminidase (IC50, 3.5 μM) and TNF-α (IC 50, 2.2 μM), was more potent than NO-DA or NA-DA. Additionally, NP-DA markedly suppressed the formation of prostaglandin E2, prostaglandin D2 and leukotriene C4, corresponding to pro-inflammatory lipid mediators in asthma. In the mechanistic analyses, where the effect of NP-DA on the FcεRI cascade was examined, NP-DA significantly inhibited the phosphorylation and expression of Syk, but not Lyn. And, NP-DA also suppressed phosphorylation of ERK1/2 and Akt. Further, NP-DA decreased the phosphorylation of cPLA2 and 5-lipoxygenase (5-LO), but not cyclooxygenase-2 (COX-2). Based on these results, it is suggested that NP-DA exert anti-allergic effect on allergic response through suppressing the activation of Syk, ERK1/2, Akt, cPLA2 and 5-LO. Besides, a strong inhibition of COX-2 activity by NP-DA may be additional mechanism for its anti-allergic action. Such an anti-allergic action of N-acyl dopamines may contribute to further information about biological functions of N-acyl dopamines. © 2013 AOCS. Source

Sohn K.,Konkuk University
Personality and Individual Differences | Year: 2016

Men have evolved to exhibit a desire for chastity and sexual fidelity and an abhorrence of promiscuity in long-term mates. We investigated whether these preferences manifest themselves even in an unlikely situation (prostitution) by observing men's behavior. We considered 8817 prostitutes under age 45 who worked in Indonesian cities in 2002-2004. We measured female promiscuity by experience in prostitution and applied OLS to determine whether clients paid more to less experienced prostitutes. After controlling for a set of characteristics of prostitutes and clients, we found that compared to prostitutes with an experience ≤ 1 year, prostitutes with an experience of 2-4 years earned 4.2% less, and those with an experience > 4 years earned 7.7% less. The difference is great because a value of 4.2% is just under the daily expenditure per capita on food. The relationship was more pronounced for prostitutes of high fertile age and for prostitutes with greater negotiability. It seems that the preferences are strongly built in men's psychology. © 2016 Elsevier Ltd. Source

Han S.,Konkuk University | Kim M.-S.,Kangwon National University | Park H.S.,Kangwon National University
IEEE Transactions on Automation Science and Engineering | Year: 2012

In this paper, an efficient development environment for vertical integration of many tasks involved with robot programming, called Open software Platform for Robotic Services (OPRoS), is presented. It covers from the control of hardware (HW) devices to the execution of complicated application programs. Based on general software (SW) architecture, standardized components with design patterns, frameworks, and servers are offered for developing robot SW applications easily and efficiently. Specially, an easy and one-stop Integrated Development Environment (IDE) and simulation tools are provided to make the management and debugging easier, and to check performance in advance. For an all-level development environment, the IDE of OPRoS supports development from low-level device controls to high-level contents composition, and hence, many programs ranging from HW device programs to complicated applications can be developed and integrated in a single development environment. Additionally, OPRoS makes all modules and components undergo the proper evaluation and test, which avoids potential errors due to incomplete coding. As a comprehensive platform for robot SW applications, OPRoS provides convenient environments for all development steps from editing through verification to execution. © 2004-2012 IEEE. Source

Yoon J.P.,Kyungpook National University | Chung S.W.,Konkuk University | Kim S.H.,Seoul National University | Oh J.H.,Seoul National University
Journal of Shoulder and Elbow Surgery | Year: 2013

Hypothesis: The lift-off, internal rotation lag sign, belly-press, and bear-hug tests are widely used toevaluate the integrity of the subscapularis. We hypothesized that these tests might reflect different types of subscapularis tears and sought to ascertain whether these tests accurately determine the severity of the internal rotation strength deficit and fatty degeneration. Methods: Isokinetic testing and the 4 clinical tests were used preoperatively to evaluate 312 patients who had undergone arthroscopic rotator cuff surgery. Of these, 37 patients had a full-thickness subscapularis tear, 96had a partial-thickness tear, and 179 had no tear. Results: For differentiating any tears from an intact subscapularis, the most sensitive test was the belly-press test (27.8%), and the most specific test was the lift-off test (100%). For differentiating a full-thickness tear from a partial tear, the most sensitive test was the belly-press test (56.8%), and the most specific was the lift-off test (96.9%). A positive lift-off test also most reflected loss of internal rotation strength (mean, 72.2%; 95% confidence interval, 61.9-82.5), followed by the internal rotation lag sign (55.1%; 44.2-66.1) and the belly-press test (45.9%; 36.4-54.4). Conclusions: A positive lift-off test was highly specific for the detection of a full-thickness subscapularis tear and to reflect severe fatty degeneration. The lift-off, internal rotation lag sign, belly-press, and bear-hug tests sequentially predict internal rotation strength deficit and provide discrimination of internal rotation strength impairment. © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Source

Johnston M.,Massachusetts Institute of Technology | Lee H.-W.,Konkuk University | Modiano E.,Massachusetts Institute of Technology
Journal of Lightwave Technology | Year: 2013

This paper addresses the problem of logical topology design for optical backbone networks subject to stochastic traffic demands. The network design problem is broken into three tasks: traffic routing, capacity allocation, and link placement. While the routing and capacity allocation subproblem can be formulated using convex optimization, it is prohibitive to add the link placement component to the nonlinear formulation since the link placement problem involves integer variables. To address this issue, we develop a linear formulation for the routing and capacity allocation subproblem by applying tools from robust optimization. We show that this linear formulation performs comparably to the optimal nonlinear formulation. Our formulation can then be used to solve the link-placement subproblem for stochastic traffic. We show that optimal logical topologies for deterministic traffic demands are not necessarily optimal for stochastic traffic demands. We develop algorithms for finding logical topologies optimized for stochastic traffic. © 1983-2012 IEEE. Source

Mo J.-H.,Dankook University | Kim J.-H.,Dankook University | Lim D.J.,Konkuk University | Kim E.H.,Dankook University
American Journal of Rhinology and Allergy | Year: 2014

Background: Hypoxia-inducible factor (HIF) 1alpha is expressed under hypoxic conditions and plays an important role in immune and inflammatory responses. The role of HIF-1alpha in allergic airways has been investigated mainly in bronchial asthma. This study investigated the role of HIF-1alpha in mouse models and patients with allergic rhinitis (AR). Methods: Balb/c mice were sensitized with ovalbumin (OVA) and alum and were challenged intranasally with OVA. The HIF-1alpha inhibitor, 2-methoxyestradiol (2-ME), was administered intraperitoneally and multiple parameters of allergic responses were evaluated. HIF-1alpha and vascular endothelial growth factor (VEGF) mRNA and protein expression were also evaluated in patients with AR and a correlation analysis between mRNA expression and allergic symptoms was performed. Results: In mouse models, the HIF-1alpha inhibitor 2-ME reduced allergic symptoms and eosinophilic infiltration into the nasal mucosa. 2-ME was found to suppress IgE production and inhibit local Th2 cytokine transcription in the nasal mucosa and systemic Th2 cytokine production by splenocytes. 2-ME also decreased HIF-1 and VEGF expression in nasal mucosa. An increase in HIF-1alpha and VEGF expression in the nasal mucosa of patients with AR was also observed. Conclusion: Our data suggest that HIF-1alpha plays an important role in mouse models and patients with AR. HIF-1alpha inhibitors induce antiallergic effects by decreasing both local and systemic Th2 cytokine (IL-4 and IL-5) production, IgE production, and eosinophil infiltration into the nasal mucosa in an AR model. HIF-1alpha and VEGF expression increased in the nasal mucosa of patients with AR, showing the role of HIF-1alpha in disease pathogenesis. Copyright © 2014 Ocean Side Publications Inc. Source

Hong C.A.,Korea Advanced Institute of Science and Technology | Kim J.S.,Korea Advanced Institute of Science and Technology | Lee S.H.,Korea Advanced Institute of Science and Technology | Kong W.H.,Korea Advanced Institute of Science and Technology | And 3 more authors.
Advanced Functional Materials | Year: 2013

A highly efficient approach for target-specific gene silencing based on a reductively dissociable nanogel incorporating small interfering RNA (siRNA) crosslinked with linear polyethylenimine (LPEI) via disulfide bonds is presented. Thiol-terminated siRNA at both 3′-ends is electrostatically complexed with thiol-grafted LPEI. The prepared siRNA/LPEI complex contains inter- and intramolecular linkages, generating a mutually crosslinked siRNA/LPEI nanogel (MCN) that exhibits excellent structural stability against the addition of heparin but is readily disintegrated to biologically active, monomeric siRNA upon exposure to reductive conditions. Accordingly, the highly condensed, stable MCN shows greatly enhanced cellular uptake and gene silencing efficiency compared to the siRNA/LPEI complexes without crosslinks or with only LPEI-mediated crosslinks. A highly condensed, stable nanogel comprising mutually crosslinked small interfering RNA (siRNA) and linear polyethylenimine (LPEI) via disulfide bonds within an individual polyplex shows greatly enhanced cellular uptake and gene-silencing efficiency. The reducible nanogels are disintegrated readily to biologically active siRNA and low-molecular-weight cationic fragments upon exposure to reductive conditions, allowing RNA interference (RNAi)-mediated gene silencing without severe cytotoxicity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Kang S.-C.,Korea Advanced Institute of Science and Technology | Koh H.-M.,Seoul National University | Choo J.F.,Konkuk University
Probabilistic Engineering Mechanics | Year: 2010

The response surface method (RSM) is widely adopted for structural reliability analysis because of its numerical efficiency. However, the RSM is time consuming for large-scale applications and sometimes shows large errors in the calculation of the sensitivity of the reliability index with respect to random variables. In order to overcome these problems, this study proposes an efficient RSM applying a moving least squares (MLS) approximation instead of the traditional least squares approximation generally used in the RSM. The MLS approximation gives higher weight to the experimental points closer to the most probable failure point (MPFP), which allows the response surface function (RSF) to be closer to the limit state function at the MPFP. In the proposed method, a linear RSF is constructed at first and a quadratic RSF is formed using the axial experimental points selected from the reduced region where the MPFP is likely to exist. The RSF is updated successively by adding one new experimental point to the previous set of experimental points. Numerical examples are presented to demonstrate the improved accuracy and computational efficiency of the proposed method compared to the conventional RSM. © 2010 Elsevier Ltd. All rights reserved. Source

Shim C.S.,Konkuk University
Clinical Endoscopy | Year: 2012

Tumors in the cervical portion of the esophagus have traditionally been more difficult to manage. The implantation in the cervical esophagus is a technically demanding procedure. The implantation of modified self-expandable metal stents (SEMSs) was very effective perorally under endoscopic and fluoroscopic guidance. Experience with SEMS has revealed an increased risk of migration when either covered stents are used or a stent is implanted across the gastroesophageal junction. The modified, covered, esophageal stents appear to prevent stent migration and improve dysphagia in patients with malignant tumor stenosis at the esophagogastric junction. Besides heartburn, regurgitation is sometimes very distressing to patients and may lead to fatal aspiration due to reflux after stenting in esophagogastric junction. These symptoms can be reduced by the use of valved stent. The long S-shape valve is very effective in preventing acid reflux and valve inversion. © 2012 Korean Society of Gastrointestinal Endoscopy. Source

Kim W.,Samsung | Chattopadhyay D.,Saha International | Park J.-B.,Konkuk University
Energy | Year: 2010

Carbon costs - either in the form of a carbon tax or through permit prices in an emissions trading scheme - would ultimately be reflected in higher electricity prices. Carbon cost "pass-through" is critical to the survival of existing coal generation assets and has been discussed widely as a measure of business impact in the electricity industry. This paper sets out in a structured way the factors that determine price pass-through and why this may differ greatly across different systems. Although the basic concept of price pass-through is simple, a clear understanding of the underlying factors is critical to developing insights on how carbon cost would impact on existing coal generation businesses. It is shown that pass-through can vary drastically if the underlying dispatch potential of generators varies significantly across alternative emissions reduction scenarios. It can also vary depending on the availability of competing cleaner forms of generation. Pass-through as a measure of business performance is, therefore, hard to generalize across different circumstances and should be interpreted carefully. © 2010 Elsevier Ltd. Source

Fe3O4-decorated graphene balls were prepared by a spray pyrolysis process. Analysis by Raman spectroscopy and X-ray photoelectron spectroscopy indicated that the spray pyrolysis at 800 °C resulted in the complete reduction of graphene oxide sheets containing oxygen functional groups into graphene sheets, leading to the formation of Fe3O4-decorated graphene balls. The graphene content in the composite ball was 27 wt%. The Brunauer-Emmett-Teller surface area of the Fe3O4-decorated graphene balls was as high as 130 m2 g-1. The initial discharge and charge capacities of the Fe3O4-decorated graphene balls at a high current density of 7 A g-1 were 1210 and 843 mAh g-1, respectively, and the discharge capacity was as high as 690 mAh g-1 even after 1000 cycles. The stable reversible discharge capacities of the Fe3O4-decorated graphene balls decreased from 1040 to 540 mAh g-1 with the increase in current density from 1 to 30 A g-1. The Fe3O4-decorated graphene balls with a uniform distribution of ultrafine Fe3O4 nanocrystals below 15 nm showed superior electrochemical properties as anode materials for lithium ion batteries. The overall structure of the Fe3O4-decorated graphene balls was maintained even after long-term cycling. © 2014 Elsevier Ltd. All rights reserved. Source

Cheung K.,National Center for Theoretical science | Cheung K.,National Tsing Hua University | Cheung K.,Konkuk University | Keung W.-Y.,National Center for Theoretical science | And 2 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

Rare decay modes of the newly discovered standard-model-like Higgs boson h may test the flavor-changing couplings in the leptoquark sector through the process h→τμ±. Motivated by the recently reported excess in LHC data from the CMS detector, we found that a predicted branching fraction Br(h→τμ±) at the level of 1% is possible even though the coupling parameters are subjected to the stringent constraint from the null observation of τ→μγ, where the destructive cancellation among amplitudes is achievable by fine-tuning. © 2016 American Physical Society. Source

Kwak D.,Pohang University of Science and Technology | Kwak D.,Samsung | Lim J.A.,Korea Institute of Science and Technology | Kang B.,Pohang University of Science and Technology | And 2 more authors.
Advanced Functional Materials | Year: 2013

The high-precision deposition of highly crystalline organic semiconductors by inkjet printing is important for the production of printed organic transistors. Herein, a facile nonconventional lithographic patterning technique is developed for fabricating banks with microwell structures by inkjet printing solvent droplets onto a polymer layer, thereby locally dissolving the polymer to form microwells. The semiconductor ink is then inkjet-printed into the microwells. In addition to confining the inkjet-printed organic semiconductor droplets, the microwells provide a platform onto which organic semiconductor molecules crystallize during solvent evaporation. When printed onto the hydrophilic microwells, the inkjet-printed 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN) molecules undergo self-organization to form highly ordered crystalline structures as a result of contact line pinning at the top corner of the bank and the outward hydrodynamic flow within the drying droplet. By contrast, small crystallites form with relatively poor molecular ordering in the hydrophobic microwells as a result of depinning of the contact line along the walls of the microwells. Because pinning in the hydrophilic microwells occurred at the top corner of the bank, treating the surfaces of the dielectric layer with a hydrophobic organic layer does not disturb the formation of the highly ordered TIPS-PEN crystals. Transistors fabricated on the hydrophilic microwells and the hydrophobic dielectric layer exhibit the best electrical properties, which is explained by the solvent evaporation and crystallization characteristics of the organic semiconductor droplets in the microwell. These results indicate that this technique is suitable for patterning organic semiconductor deposits on large-area flexible substrates for the direct-write fabrication of high-performance organic transistors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Lee J.,Korea Advanced Institute of Science and Technology | Lee P.,Korea Advanced Institute of Science and Technology | Lee H.B.,Korea Advanced Institute of Science and Technology | Hong S.,Korea Advanced Institute of Science and Technology | And 6 more authors.
Advanced Functional Materials | Year: 2013

As an alternative to the brittle and expensive indium tin oxide (ITO) transparent conductor, a very simple, room-temperature nanosoldering method of Ag nanowire percolation network is developed with conducting polymer to demonstrate highly flexible and even stretchable transparent conductors. The drying conducting polymer on Ag nanowire percolation network is used as a nanosoldering material inducing strong capillary-force-assisted stiction of the nanowires to other nanowires or to the substrate to enhance the electrical conductivity, mechanical stability, and adhesion to the substrate of the nanowire percolation network without the conventional high-temperature annealing step. Highly bendable Ag nanowire/conducting polymer hybrid films with low sheet resistance and high transmittance are demonstrated on a plastic substrate. The fabricated flexible transparent electrode maintains its conductivity over 20 000 cyclic bends and 5 to 10% stretching. Finally, a large area (A4-size) transparent conductor and a flexible touch panel on a non-flat surface are fabricated to demonstrate the possibility of cost-effective mass production as well as the applicability to the unconventional arbitrary soft surfaces. These results suggest that this is an important step toward producing intelligent and multifunctional soft electric devices as friendly human/electronics interface, and it may ultimately contribute to the applications in wearable computers. A very simple, room-temperature nanosoldering of a Ag nanowire percolation network by conducting-polymer-assisted nanowire joining is developed to demonstrate highly flexible, and even stretchable, transparent conductors. Furthermore, a large area (A4-size) transparent conductor and a flexible touch panel on a non-flat surface are fabricated to demonstrate the possibility of cost-effective mass production and the applicability to the unconventional arbitrary soft, non-flat surfaces. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Kang S.K.,Seoul National University of Science and Technology | Song J.,Konkuk University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

A hint of a new resonance at a mass of 750 GeV has been shown in the diphoton channel of the Run-2 LHC data. The observed signal rate is usually too large to interpret it as a new scalar boson in the context of weakly coupled renormalizable models. One way is to reduce its total decay rate, which is possible if the CP-even heavy Higgs boson H0 in the aligned two Higgs doublet model becomes top-phobic. To ensure sufficient gluon fusion production, we introduce vector-like quarks (VLQ). The Higgs precision data as well as the exclusion limits from no excesses in other resonance searches through Zγ, bb, τ+τ-, and jj channels at the Run-1 LHC are comprehensively studied. In Type I, the top-phobic H0 cannot simultaneously explain the 750 GeV diphoton excess and the Higgs precision data since the same Yukawa couplings of the up-type and down-type VLQs to H0 always make more contribution to the diphoton signal rate of the standard model Higgs boson than that of H0. In Type II, small Yukawa coupling of the up-type VLQ but sizable Yukawa coupling of the down-type VLQ is shown to explain the signal while satisfying other LHC exclusion limits. © 2016 American Physical Society. Source

Kim K.J.,Konkuk University | Lim K.-Y.,University of Seoul | Kim Y.-W.,University of Seoul | Kim H.C.,National Fusion Research Institute
Journal of the American Ceramic Society | Year: 2013

Al- and B-doped 3C-SiC ceramics were prepared by hot-pressing powder compacts containing submicrometer-sized β-SiC, precursors of 5 wt% nanosized β-SiC, and an optional additive (Al or B) in an Ar atmosphere. Electron probe microanalysis (EPMA) investigation on the obtained specimens revealed that a portion of the doped Al and B atoms substituted the zinc blende lattice sites. The temperature-dependent electrical resistivity data of the Al- and B-doped SiC specimens were measured in the 4-300 K range and compared with those of an undoped specimen. The Al- and B-doped SiC specimens exhibited resistivities that were as high as ∼103 Ω cm at room temperature and ∼105 and ∼104 Ω cm, respectively, below 100 K. These values are larger than those of the undoped SiC specimen by a factor of ∼104. Such high resistivities of the impurity-doped specimens are attributable to the carrier compensation by the Al- and B-derived acceptors located well above the valence-band edge of 3C-SiC. Photoluminescence investigation revealed that the Al- and B-doped specimens exhibited emission profile below 2 eV, implying the existence of the acceptors. © 2013 The American Ceramic Society. Source

Lee K.-S.,Konkuk University
Speech Communication | Year: 2014

A voice transformation (VT) method that can make the utterance of a source speaker mimic that of a target speaker is described. Speaker individuality transformation is achieved by altering four feature parameters, which include the linear prediction coefficients cepstrum (LPCC), ΔLPCC, LP-residual and pitch period. The main objective of this study involves construction of an optimal sequence of features selected from a target speaker's database, to maximize both the correlation probabilities between the transformed and the source features and the likelihood of the transformed features with respect to the target model. A set of two-pass conversion rules is proposed, where the feature parameters are first selected from a database then the optimal sequence of the feature parameters is then constructed in the second pass. The conversion rules were developed using a statistical approach that employed a maximum likelihood criterion. In constructing an optimal sequence of the features, a hidden Markov model (HMM) with global control variables (GCV) was employed to find the most likely combination of the features with respect to the target speaker's model. The effectiveness of the proposed transformation method was evaluated using objective tests and formal listening tests. We confirmed that the proposed method leads to perceptually more preferred results, compared with the conventional methods. © 2014 Elsevier B.V. All rights reserved. Source

Kim K.J.,Konkuk University | Lim K.-Y.,University of Seoul | Kim Y.-W.,University of Seoul
Journal of the American Ceramic Society | Year: 2013

The electrical properties of β-SiC ceramics were found to be adjustable through appropriate AlN-Y2O3 codoping. Polycrystalline β-SiC specimens were obtained by hot pressing silicon carbide (SiC) powder mixtures containing AlN and Y2O3 as sintering additives in a nitrogen atmosphere. The electrical resistivity of the SiC specimens, which exhibited n-type character, increased with AlN doping and decreased with Y2O3 doping. The increase in resistivity is attributed to Al-derived acceptors trapping carriers excited from the N-derived donors. The results suggest that the electrical resistivity of the β-SiC ceramics may be varied in the 104-10-3 Ω·cm range by manipulating the compensation of the two impurity states. The photoluminescence (PL) spectrum of the specimens was found to evolve with the addition of dopants. The presence of N-donor and Al-acceptor states within the band gap of 3C-SiC could be identified by analyzing the PL data. © 2013 The American Ceramic Society. Source

Park S.,Hanyang University | Jung G.,Hanyang University | Hwang Y.-S.,Konkuk University | Jin E.,Hanyang University
Planta | Year: 2010

Large-scale RNA profiling revealed that high irradiance differentially regulated 577 out of 1,439 non-redundant genes of the Antarctic marine diatom Chaetoceros neogracile, represented on a custom cDNA chip, during 6 h of treatment. Among genes that were up- or down-regulated more than twofold within 30 min of treatment (310/1,439), about half displayed an acclimatory response during 6 h under high light. Expression of the remaining non-acclimatory genes also rapidly returned to initial levels within 30 min following a shift to low irradiance. High light altered expression of most of the photosynthesis genes (48/70), in contrast to genes in other functional categories. In addition, opposite response patterns were provoked in genes encoding fucoxanthin chlorophyll a/c binding protein (FCP), the main component of the diatom light-harvesting complex; high irradiance caused a decrease in expression of most FCP genes, but drove the rapid and specific up-regulation of ten others. C. neogracile responded very promptly to a change in light intensity by rapidly adjusting the transcript levels of FCP genes up-regulated by high light, and these dynamic adjustments coincided well with diatoxanthin (Dtx) levels formed by the xanthophyll cycle under the same conditions. The observation that the non-photochemical quenching (NPQ) capacity of this polar diatom was highly dependent on Dtx, which could bind to FCP and trigger NPQ, suggests that the up-regulated FCP gene products may participate in a photoprotective process as Dtx-binding proteins. © 2009 Springer-Verlag. Source

Kim J.,Yonsei University | Luo G.,Yonsei University | Bahk Y.Y.,Konkuk University | Song K.,Yonsei University
PLoS Genetics | Year: 2012

In budding yeast, the major regulator of the mitotic exit network (MEN) is Tem1, a GTPase, which is inhibited by the GTPase-activating protein (GAP), Bfa1/Bub2. Asymmetric Bfa1 localization to the bud-directed spindle pole body (SPB) during metaphase also controls mitotic exit, but the molecular mechanism and function of this localization are not well understood, particularly in unperturbed cells. We identified four novel Cdc5 target residues within the Bfa1 C-terminus: 452S, 453S, 454S, and 559S. A Bfa1 mutant in which all of these residues had been changed to alanine (Bfa1 4A) persisted on both SPBs at anaphase and was hypo-phosphorylated, despite retaining its GAP activity for Tem1. A Bfa1 phospho-mimetic mutant in which all of these residues were switched to aspartate (Bfa1 4D) always localized asymmetrically to the SPB. These observations demonstrate that asymmetric localization of Bfa1 is tightly linked to its Cdc5-dependent phosphorylation, but not to its GAP activity. Consistent with this, in kinase-defective cdc5-2 cells Bfa1 was not phosphorylated and localized to both SPBs, whereas Bfa1 4D was asymmetrically localized. BFA1 4A cells progressed through anaphase normally but displayed delayed mitotic exit in unperturbed cell cycles, while BFA1 4D cells underwent mitotic exit with the same kinetics as wild-type cells. We suggest that Cdc5 induces the asymmetric distribution of Bfa1 to the bud-directed SPB independently of Bfa1 GAP activity at anaphase and that Bfa1 asymmetry fine-tunes the timing of MEN activation in unperturbed cell cycles. © 2012 Kim et al. Source

Yu M.H.,Seoul National University | Yu M.H.,Konkuk University | Kim J.H.,Seoul National University | Yoon J.-H.,Seoul National University | And 4 more authors.
Radiology | Year: 2014

Purpose: To assess diagnostic performance and imaging features of gadoxetic acid-enhanced magnetic resonance (MR) imaging in small (≥1-cm) hepatocellular carcinoma (HCC) detection in patients with chronic liver disease. Materials and Methods: The institutional review board approved this retrospective study and waived informed consent. Sixty patients (56 men, four women; mean age, 60.1 years) with HCC (146 lesions; 70 < 1 cm, 76 ≥ 1 cm) underwent gadoxetic acid-enhanced MR imaging. HCC was confirmed at surgical resection (72 lesions; 30 < 1 cm, 42 ≥ 1 cm) or by showing interval growth with typical enhancement patterns at follow-up dynamic computed tomography or MR imaging (74 lesions; 40 < 1 cm, 34 ≥ 1 cm). Two radiologists assessed MR imaging features and graded likelihood of HCC with a five-point confidence scale. Jackk