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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>

      • 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>

      • Warehouse capacity sharing via transshipment for an integrated two-echelon supply chain

        Feng, X.,Moon, I.,Ryu, K. Elsevier Science Ltd ; Pergamon ; Elsevier Science 2017 TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANS Vol.104 No.-

        <P>Warehouse capacity constraint has been one obstacle to achieving the channel-wide optimal decision in inventory management. We studied an integrated inventory model consisting of a single vendor and multiple buyers with warehouse capacity sharing via transshipment. We proposed an optimal transshipment policy by developing nonlinear programming models and genetic algorithms as well as obtaining Karush-Kuhn-Tucker points. This inventory policy can significantly reduce the channel-wide cost and the performance is influenced by the consideration of fixed transshipment costs. Sensitivity analyses show that parameters have different impacts on the channel-wide cost and the performances of the algorithms. (C) 2017 Published by Elsevier Ltd.</P>

      • Color-stable, ITO-free white organic light-emitting diodes with enhanced efficiency using solution-processed transparent electrodes and optical outcoupling layers

        Chang, H. W.,Kim, Y. H.,Lee, J.,Hofmann, S.,Lussem, B.,Muller-Meskamp, L.,Gather, M. C.,Leo, K.,Wu, C. C. Elsevier Science B.V., Amsterdam. 2014 Organic electronics Vol.15 No.5

        In this work, we demonstrate color-stable, ITO-free white organic light-emitting diodes (WOLEDs) with enhanced efficiencies by combining the high-conductivity conducting polymer PEDOT:PSS as transparent electrode and a nanoparticle-based scattering layer (NPSL) as the effective optical out-coupling layer. In addition to efficiency enhancement, the NPSL is also beneficial to the stabilization of electroluminescent spectra/colors over viewing angles. Both the PEDOT:PSS and the NPSL can be fabricated by simple, low-temperature solution processing. The integration of both solution-processable transparent electrodes and light extraction structures into OLEDs is particularly attractive for applications since they simultaneously provide manufacturing, cost and efficiency advantages. (C) 2014 Elsevier B.V. All rights reserved.

      • SCIESCOPUS

        Optimally designed collagen/polycaprolactone biocomposites supplemented with controlled release of HA/TCP/rhBMP-2 and HA/TCP/PRP for hard tissue regeneration

        Kim, WonJin,Jang, Chul Ho,Kim, GeunHyung Elsevier 2017 Materials Science and Engineering C Vol. No.

        <P>Collagen has been widely used as a very promising material to regenerate various tissues. It is a chief component of the extracellular matrix, and encourages various biological effects conducive to tissue regeneration. However, poor mechanical stability, low processability, and high level of water absorption can lead to impaired control of growth factor release and have impeded the use of collagen as a functional biomedical scaffold. Here, to overcome the shortcomings of collagen scaffolds, we have additively manufactured collagen/polycaprolactone (PCL) biocomposites supplemented with a bioceramic (hydroxyapatite (HA)/(beta-tricalcium-phosphate (TCP)) and two growth factors (recombinant human bone morphogenetic protein-2 [rhBMP-2] and platelet-rich plasma [PRP]). Various weight fractions of PCL in the collagen/PCL composites were manipulated to select optimal growth factor release and highly active cellular responses. After the optimal concentration of PCL in the collagen/PCL scaffold was determined, biocomposites supplemented with bioceramic/growth-factors were fabricated. Continuously released growth factors were assumed to increase the in vitro cellular activities of the osteoblast-like cells (MG63) cultured on the biocomposites. In vitro cellular responses, including osteogenic activities, were examined, and results showed that compared to the HA/TCP/rhBMP-2 supplemented scaffold the HA/TCP/PRP biocomposites provide significantly high cellular activities (cell proliferation: >1.3-fold) and mineralization (calcium deposition: >1.4-fold, osteocalcin: >2.6-fold) sufficient for regenerating bone tissue. (C) 2017 Published by Elsevier B.V.</P>

      • Mechanical behavior of ultrafine-grained high-Mn steels containing nanoscale oxides produced by powder technology

        Jeon, J.,Nam, S.,Kang, S.,Shin, J.,Choi, H. Elsevier Ltd 2016 Materials & Design Vol.92 No.-

        <P>A new class of ultrafine-grained high-Mn steels containing nanoscale oxides has been developed by spark plasma sintering of ball-milled powders. During spark-plasma sintering, nanoscale manganese oxides were generated in Fe-15Mn steel, while nanoscale aluminum oxides were produced in Fe-15Mn-3A1-3Si steel because of the high affinity of aluminum for oxygen. Ultrafine-grained high-Mn steels that contain nanoscale oxides exhibited superior strength without significant loss of toughness, owing to the combined effects of grain refinement, twinning-induced plasticity (TWIP), and dispersion of nanoscale oxides. These new materials have potential for application in powder metallurgy components used in the automotive industry, such as gear sets, connecting rods, and bearing caps, which require high surface hardness as well as good core toughness. (C) 2015 Elsevier Ltd. All rights reserved.</P>

      • KCI등재SCIESCOPUS

        Highly insulating ferromagnetic cobaltite heterostructures

        Choi, Woo Seok,Kang, Kyeong Tae,Jeen, Hyoungjeen,Gai, Zheng,Lee, Ho Nyung Elsevier 2017 CURRENT APPLIED PHYSICS Vol.17 No.5

        <P>Ferromagnetic insulators are rather rare but possess great technological potential in, for example, spintronics. Individual control of ferromagnetic properties and electronic transport provides a useful design concept of multifunctional oxide heterostructures. We studied the close correlation among the magnetism, atomic structure, and electronic structure of oxide heterostructures composed of the ferromagnetic perovskite LaCoO3 and the antiferromagnetic brownmillerite SrCoO2.5 epitaxial thin film layers. By reversing the stacking sequence of the two layers, we could individually modify the electric resistance and saturation magnetic moment. The ferromagnetic insulating behavior in the heterostructures was understood in terms of the electronic reconstruction at the oxide surface/interfaces and crystalline quality of the constituent layers. (C) 2017 Elsevier B.V. All rights reserved.</P>

      • Floating rice-culture system for nutrient remediation and feed production in a eutrophic lake

        Srivastava, Ankita,Chun, Seong-Jun,Ko, So-Ra,Kim, Junhwan,Ahn, Chi-Yong,Oh, Hee-Mock Elsevier 2017 Journal of environmental management Vol.203 No.1

        <P>The increased inputs of nutrients have been demonstrated to be a major contributing factor to the eutrophication of lakes and reservoirs which can lead to the production of harmful algal/cyanobacterial blooms and deleteriously affect the aesthetics of water-bodies. Floating plant-culture systems have been widely used for the ecological remediation of eutrophic water in a cost-effective manner. We investigated the applicability of Korean japonica rice variety 'Nampyeong' in a floating-culture system in a eutrophic lake for nutrient uptake and biomass production. Chemical and organic compound compositions were analyzed two times during the growth stages of the rice plant: 98 DAT (days after transplanting) and 165 DAT. Total nitrogen and phosphorus contributed around 1.36 and 0.15 (% dry weight), respectively, in rice plant components at 165 DAT. Crude protein, lipids, fiber and ash were 4.35, 1.91, 23.66 and 5.55 (% dry weight), respectively. In addition, microcystin levels in the rice plant components ranged from 0.0008 to 0.002 gig and did not exceed the recommended tolerable limits. These results suggested that the developed floating rice-culture system showed a good potential as a holistic management approach in terms of nutrient reduction, rice production for further use as feed and for bloom control. (C) 2017 Elsevier Ltd. All rights reserved.</P>

      • Fluorescent nanobiosensors for the targeted detection of foodborne bacteria

        Bhardwaj, Neha,Bhardwaj, Sanjeev K.,Nayak, Manoj K.,Mehta, Jyotsana,Kim, Ki-Hyun,Deep, Akash Elsevier 2017 Trends in analytical chemistry Vol.97 No.-

        <P>Foodborne diseases caused by bacterial pathogens are severe threats to human health. Conventional culture based microbiologic methods for the analysis of bacterial contamination in food products are laborious, time consuming and require specific skills. Immunologic and polymerase chain reaction (PCR) based molecular methods are also costly, lack specificity, and may yield false results. As outlined in this review, fluorescent nanobiosensors have now become effective alternative tools for rapid and routine detection of foodborne bacteria. We provide an overview of the use of different fluorescent nano materials in the development of nanobiosensors with special emphasis on underlying detection principles, sensitivity, specificity, and their capability of multiplexed analysis. In summary, the diverse nanomaterials used for bacterial detection are critically analyzed with respect to their advantages and limitations for future applications in the diagnosis of foodborne bacteria. (C) 2017 Elsevier B.V. All rights reserved.</P>

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