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      • Mitral Loop Cerclage Annuloplasty for Secondary Mitral Regurgitation

        Park, Y.H.,Chon, M.K.,Lederman, R.J.,Sung, S.C.,Je, H.G.,Choo, K.S.,Lee, S.H.,Shin, E.S.,Kim, J.S.,Hwang, K.W.,Lee, S.Y.,Chun, K.J.,Kim, C.M.,Kim, J.H. Elsevier 2017 JACC. Cardiovascular interventions Vol.10 No.6

        <P>OBJECTIVES This is an early feasibility clinical test of mitral loop cerclage annuloplasty to treat secondary mitral valve regurgitation. BACKGROUND Secondary mitral regurgitation is characterized by cardiomyopathy, mitral annular enlargement, and leaflet traction contributing to malcoaptation. Transcatheter mitral loop cerclage applies circumferential compression to the mitral annulus by creating a loop through the coronary sinus across the interventricular septum, protecting entrapped coronary arteries from compression, and interactive annular reduction under echocardiographic guidance. This is the first human test of mitral loop annuloplasty. METHODS Five subjects with severe symptomatic secondary mitral regurgitation underwent mitral loop cerclage, with echocardiographic and computed tomography follow-up over 6 months. RESULTS Mitral loop cerclage was successful in 4 of 5 subjects and aborted in 1 of the 5 because of unsuitable septal coronary vein anatomy. Immediately and over 6 months, measures of both mitral valve regurgitation (effective orifice area and regurgitation fraction) and chamber dimensions (left atrial and left ventricular volumes) were reduced progressively and ejection fractions increased. Two with persistent and permanent atrial fibrillation spontaneously reverted to sinus rhythm during follow-up. One subject experienced a small myocardial infarction from an unrecognized small branch coronary occlusion. Another, experiencing cardiogenic shock at baseline, died of intractable heart failure after 6 weeks. CONCLUSIONS In this first human test, mitral loop cerclage annuloplasty was successful in 4 of 5 attempts, caused reverse remodeling (reduction in secondary mitral regurgitation and heart chamber volumes), and suggested electrical remodeling (reversion of atrial fibrillation). Further evaluation is warranted. (C) 2017 by the American College of Cardiology Foundation. Published by Elsevier. All rights reserved.</P>

      • Orbital hybridization mechanism for the enhanced photoluminescence in edge-functionalized sp<sup>2</sup> carbon clusters

        Kang, B.,Choi, Y.,Kim, B.S.,Youn, I.S.,Lee, G. Pergamon Press ; Elsevier Science Ltd 2016 Carbon Vol.109 No.-

        <P>Using the first principles methods, we performed systematic study on the effect of edge-functional groups on the electronic energy levels and the optical properties of sp(2) carbon clusters. It is found that the intrinsic pi and pi* orbitals are weakly altered by oxygen-bearing functional groups, but it is significantly disrupted by pyrrolic groups. Thereby the oscillator strength of the lowest-energy transition is found to be much stronger for the pyrrolic group functionalized cluster than for the carboxyl group. From our results being consistent with the experimental reports, we suggest that the photoluminescence enhancement is caused by a perturbation of the intrinsic, frontier molecular orbitals by edge groups. (C) 2016 Elsevier. Ltd. All rights reserved.</P>


        Synthesis and characterization of electrospun PVdF-HFP/silane-functionalized ZrO<sub>2</sub> hybrid nanofiber electrolyte with enhanced optical and electrochemical properties

        Puguan, J.M.C.,Chung, W.J.,Kim, H. Elsevier 2016 SOLID STATE SCIENCES Vol.62 No.-

        <P>A facile method to produce a hybrid of organic-inorganic nanofiber electrolyte via electrospinning is hereby presented. The incorporation of functionalized zirconium oxide (ZrO2) nanoparticles into poly(-vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and complexed with lithium tri-fluoromethanesulfonate (LiCF3SO3) provided an enhanced optical transmissivity and ionic conductivity. The dependence of the nanofiber's morphology, optical and electrochemical properties on the various ZrO2 loading was studied. Results show that while nanofiller content was increased, the diameter of the nanofibers was reduced. The improved bulk ionic conductivity of the nanofiber electrolyte was at 1.96 x 10(-5) S cm(-1). Owing to the enhanced dispersibility of the 3-(trimethoxysilyl) propyl methacrylate (MPS) functionalized ZrO2, the optical transmissivity of the nanofiber electrolyte was improved significantly. This new nanofiber composite electrolyte membrane with further development has the potential to be next generation electrolyte for energy efficient windows like electrochromic devices. (C) 2016 Elsevier Masson SAS. All rights reserved.</P>


        Electrospun nanofibers: New generation materials for advanced applications

        Thenmozhi, S.,Dharmaraj, N.,Kadirvelu, K.,Kim, H.Y. Elsevier 2017 Materials science and engineering B. Advanced Func Vol.217 No.-

        <P>Electrospinning (E-spin) is a unique technique to fabricate polymeric as well as metal oxide nanofibers. Research on electrospun nanofibers is a very active field in material science owing to their novel applications in diverse domains. The main focus of this review is to provide an insight into E-spin technique by understanding the working principle, influencing parameters and applications of nanofibers in different walks of life. Several hundreds of papers are published on the preparation, modification and applications of nanofibers produced by E-spin technique in the areas like sensor development, decontamination, energy storage, biomedical and catalysis etc. Details on the industrial scale development of E-spin technique, current scenario and future developments are also covered in this review. (C) 2017 Elsevier B.V. All rights reserved.</P>

      • Clinical benefit of nomogram for predicting positive resection margins in breast conserving surgery

        Lee, E.-S.,Han, W.,Shin, H.-C.,Takada, M.,Ryu, H.S.,Cho, N.,Kim, M.K.,Kim, J.,Yoo, T.-k.,Moon, H.-G.,Toi, M.,Moon, W.K.,Park, I.-A.,Noh, D.-Y. Elsevier 2016 European journal of surgical oncology Vol.42 No.8

        <P>Purpose: Previously, we reported a nomogram for the prediction of positive resection margin (RM) after breast conserving surgery (BCS). This study was conducted to evaluate the clinical usefulness of the nomogram. Methods: Prospective patients who underwent operations using the nomogram between July 2012 and August 2013 (nomogram group; N = 260) were compared with past control patients who underwent operations between July 2010 and October 2011 and underwent frozen section biopsy (FSB) without use of the nomogram (N = 266). In the nomogram group, an intraoperative assessment of RM using FSB was only performed when the nomogram score was higher than predefined cut-off (>80). In addition, we conducted retrospective analysis of additional 181 patients who received BCS in another institute (Kyoto University Hospital). These patients did not undergo FSBs for RMs. Results: Of 260 patients, 161 (61.9%) presented low nomogram scores and avoided FSB. The surgical decision to use the nomogram did not significantly increase reoperation rate due to positive RM compared with the control FSB group (4.6% vs. 3.8%, p = 0.47). The surgery time was significantly reduced by 18.1% (mean 14.7 min) in nomogram group (p < 0.001). Of 99 nomogram high-score patients, 14 presented with positive RM on FSB and 11 of them avoided reoperation. In the Kyoto cohort, the reoperation rate was significantly lower in low-score patients than in high-score patients (2.7% vs. 11.4%, p < 0.001). Conclusions: We showed that our nomogram is useful to reduce FSBs without increasing reoperation rate for surgeons who perform routine FSBs. For most surgeons, it can give useful information about the possibility of tumor-positive RMs. (C) 2016 Elsevier Ltd. All rights reserved.</P>

      • An intelligent hybrid trading system for discovering trading rules for the futures market using rough sets and genetic algorithms

        Kim, Youngmin,Ahn, Wonbin,Oh, Kyong Joo,Enke, David Elsevier 2017 Applied soft computing Vol.55 No.-

        <P>Discovering intelligent technical trading rules from nonlinear and complex stock market data, and then developing decision support trading systems, is an important challenge. The objective of this study is to develop an intelligent hybrid trading system for discovering technical trading rules using rough set analysis and a genetic algorithm (GA). In order to obtain better trading decisions, a novel rule discovery mechanism using a GA approach is proposed for solving optimization problems (i.e., data discretization and reducts) of rough set analysis when discovering technical trading rules for the futures market. Experiments are designed to test the proposed model against comparable approaches (i.e., random, correlation, and GA approaches). In addition, these comprehensive experiments cover most of the current trading system topics, including the use of a sliding window method (with or without validation dataset), the number of trading rules, and the size of training period. To evaluate an intelligent hybrid trading system, experiments were carried out on the historical data of the Korea Composite Stock Price Index 200 (KOSPI 200) futures market. In particular, trading performance is analyzed according to the number of sets of decision rules and the size of the training period for discovering trading rules for the testing period. The results show that the proposed model significantly outperforms the benchmark model in terms of the average return and as a risk-adjusted measure. (C) 2017 Elsevier B.V. All rights reserved.</P>

      • In vitro single-vessel enzymatic synthesis of novel Resvera-A glucosides

        Shin, J.Y.,Pandey, R.P.,Jung, H.Y.,Chu, L.L.,Park, Y.I.,Sohng, J.K. Elsevier Scientific Pub 2016 Carbohydrate research Vol.424 No.-

        <P>An in vitro enzymatic glycosylation system is developed for the efficient synthesis of glucosides of 3,5-dihydroxy-N-(4-hydroxyphenyl) benzamide (resvera-A), a chemically synthesized molecule resembling resveratrol in structure. Resvera-A is a pharamacophore-based designed molecule that exhibits antioxidant, antibacterial, anti-inflammatory, and anticancer activities. In this study, an alternative cost-effective uridine diphosphate (UDP) recycling system was established to produce UDP-alpha-D-glucose through a two-step enzyme-catalyzed reaction using easily available cheap sources. This UDP-alpha-D-glucose biosynthesis system was combined with a glycosyltransferase (YjiC, from Bacillus licheniformis)-catalyzed reaction for the synthesis of glucoside derivatives of resvera-A. The side product of the glycosylation reaction, UDP, was used as a precursor for the biosynthesis of UDP-alpha-D-glucose, which is used by YjiC for glycosylation, thus recycling UDP. As a result, two novel molecules, resvera-A 3-O-alpha-D-glucoside (42.33 mg, 2.10 mM, 0.84 mg/mL) and resvera-A 4'-O-alpha-D-glucoside (99.38 mg, 4.87 mM, 1.98 mg/mL), were synthesized within 4 h from 50 mL preparative scale reaction using only 0.1 mM of UDP-alpha-D-glucose, 100 folds lower concentration than the concentration of resvera-A (10 mM) used. Structures of both products were elucidated using liquid chromatography, mass spectroscopy, and nuclear magnetic resonance analysis. (C) 2016 Elsevier Ltd. All rights reserved.</P>

      • Evaluation of compressibility and small strain stiffness characteristics of sand reinforced with discrete synthetic fibers

        Choo, H.,Yoon, B.,Lee, W.,Lee, C. Elsevier Applied Science Publishers, Ltd ; Elsevie 2017 Geotextiles and geomembranes Vol.45 No.4

        <P>This experimental investigation evaluates the compressibility and small strain stiffness of sand reinforced with discrete synthetic fibers. Varying fiber contents (FC), fiber aspect ratios (AR), and void ratios were selected as testing variables in this study, and the modified oedometer tests were conducted to measure the compression index (C-c) and maximum shear modulus (Gmax) of fiber-reinforced sand. The results of this study demonstrate that the Cc of the tested fiber-reinforced sand increases with an increase in FC because the packing of sand grains in the fiber-reinforced sand is very loose due to a disruption of direct contact between the sand grains due to the presence of long discrete fibers. Additionally, this disruption of direct contact between sand grains due to the fibers results in a reduction of interparticle contact and coordination number between sand grains. Therefore, the Gmax of tested fiber-reinforced sand decreases with an increase in FC. Most notably, the Gmax of the tested fiber-reinforced sand with varying FC and AR can be expressed as a single function of the void ratio at a given applied stress, which implies that the inclusion of fibers just alters the packing state of sand grains, and the interparticle contact stiffness is mainly determined by the contacts between sand grains. (C) 2017 Elsevier Ltd. All rights reserved.</P>


        Ex-situ atomic force microscopy on the growth mode of SrRuO<sub>3</sub> epitaxial thin film

        Kim, B.,Lee, S.A.,Seol, D.,Choi, W.S.,Kim, Y. ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.12

        <P>The functional properties of devices based on perovskite oxides depend strongly on the growth modes that dramatically affect surface morphology and microstructure of the hetero-structured thin films. To achieve atomically flat surface morphology, which is usually a necessity for the high quality devices, understanding of the growth mechanism of heteroepitaxial thin film is indispensable. In this study, we explore heteroepitaxial growth kinetics of the SrRuO3 using intermittent growth scheme of pulsed laser epitaxy and ex-situ atomic force microscopy. Two significant variations in surface roughness during deposition of the first unit cell layer were observed from atomic force microscopy indicating the possible formation of the half unit cell of the SrRuO3 before the complete formation of the first unit cell. In addition, layer-by-layer growth mode dominated during the first two unit cell layer deposition of the SrRuO3 thin film. Our observation provides underlying growth mechanism of the heteroepitaxial SrRuO3 thin film on the SrTiO3 substrate during the initial growth of the thin film. (C) 2017 Elsevier B.V. All rights reserved.</P>

      • Dual function of quaternary ammonium in Zn/Br redox flow battery: Capturing the bromine and lowering the charge transfer resistance

        Jeon, Jae-Deok,Yang, Hyeon Sun,Shim, Joonmok,Kim, Hyun Sik,Yang, Jung Hoon Elsevier 2014 ELECTROCHIMICA ACTA Vol.127 No.-

        During the charging of a Zn/Br redox flow battery, cyclic voltammetry and electrochemical impedance spectroscopy measurements were carried out in-situ. As the state of charge (SOC) increased, some polybromide complex accumulated on the Br-side electrode surface and showed a positive effect on the adsorption of bromide ion as well as bromine. The deposition of polybromide complex onto the electrode surface was identified by SEM, EDS, and Raman spectroscopy. As a result, the charge transfer resistance for bromine oxidation decreased from 2.13 ohm to 1.27 ohm as the SOC increased from 0.0% to 80.0%. This may be due to the amphiphilic characteristics of the polybromide complex. While the solution resistance for catholyte was independent of the SOC, that for anolyte sharply decreased with increasing SOC. This could be explained by the increase in zinc ion mobility and the anolyte thickness reduction by growth of zinc metal dendrites. (C) 2014 Elsevier Ltd. All rights reserved.

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