18,359 research outputs found

    Quantum Boltzman equation study for the Kondo breakdown quantum critical point

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    We develop the quantum Boltzman equation approach for the Kondo breakdown quantum critical point, involved with two bands for conduction electrons and localized fermions. Particularly, the role of vertex corrections in transport is addressed, crucial for non-Fermi liquid transport of temperature linear dependence. Only one band of spinons may be considered for scattering with gauge fluctuations, and their associated vertex corrections are introduced in the usual way, where divergence of self-energy corrections is cancelled by that of vertex corrections, giving rise to the physically meaningful result in the gauge invariant expression for conductivity. On the other hand, two bands should be taken into account for scattering with hybridization excitations, giving rise to coupled quantum Boltzman equations. We find that vertex corrections associated with hybridization fluctuations turn out to be irrelevant due to heavy mass of spinons in the so called decoupling limit, consistent with the diagrammatic approach showing the non-Fermi liquid transport

    Real-time, step-wise, electrical detection of protein molecules using dielectrophoretically aligned SWNT-film FET aptasensors

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    Aptamer functionalized addressable SWNT-film arrays between cantilever electrodes were successfully developed for biosensor applications. Dielectrophoretically aligned SWNT suspended films made possible highly specific and rapid detection of target proteins with a large binding surface area. Thrombin aptamer immobilized SWNT-film FET biosensor resulted in a real-time, label-free, and electrical detection of thrombin molecules down to a concentration of ca. 7 pM with a step-wise rapid response time of several seconds.X113338sciescopu

    Inhibition of iNOS and DNA Oxidation by Methanol Extract of Schizonepeta tenuifolia

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    Purpose: To investigate the antioxidant properties of the methanol extract of S. tenuifolia as well as its effect on inducible nitric oxide synthase (iNOS) and cycleooxygenase-2 (COX-2) expression in lipopolysaccharides (LPS)-induced cell damage in macrophage cells.Methods: The antioxidant activities of the plant extract were explored by measuring free radical scavenging activity, viz, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO), and deoxyribose oxidation levels. The mechanism of antioxidant action of the extract was determined by Western blot analysis for iNOS and COX-2 expression in LPS-stimulated RAW 264.7 cells.Results: The extract contained antioxidant components, including phenolics, flavonoids and anthocyanin and exerted significant radical scavenging activity in a dose-dependent manner. It also produced deoxyribose oxidation and dramatic reducing power. Production of iNOS induced by LPS was significantly inhibited by the extract, suggesting that the extract inhibits nitric oxide (NO) production by suppressing iNOS expression. However, COX-2 induced by LPS was not significantly affected by the extract.Conclusion: These results suggest that the methanol extract of S. tenuifolia exerts significant antioxidant activity via inhibition of free radicals, iNOS and DNA oxidation

    Visualizing Atomic-Scale Negative Differential Resistance in Bilayer Graphene

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    We investigate the atomic-scale tunneling characteristics of bilayer graphene on silicon carbide using the scanning tunneling microscopy. The high-resolution tunneling spectroscopy reveals an unexpected negative differential resistance (NDR) at the Dirac energy, which spatially varies within the single unit cell of bilayer graphene. The origin of NDR is explained by two near-gap van Hove singularities emerging in the electronic spectrum of bilayer graphene under a transverse electric field, which are strongly localized on two sublattices in different layers. Furthermore, defects near the tunneling contact are found to strongly impact on NDR through the electron interference. Our result provides an atomic-level understanding of quantum tunneling in bilayer graphene, and constitutes a useful step towards graphene-based tunneling devices. DOI: 10.1103/PhysRevLett.110.036804X11109sciescopu

    Analysis of food components of freeze-dried Alaska Pollack (Hwangtae)

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    Physiochemical properties of freeze-dried Alaska Pollack (Hwangtae) were investigated. The moisture, crude ash and crude fat content of Hwangtae were 12.53, 5.91 and 0.94%, respectively. Contents of saccharides were found to be 3.69 mg/100 g in dried weight of glucose and 5.71 mg/100 g in dried weight of sucrose. Minerals in 100 g dry weight of Hwangtae include phosphorus (806.5 mg), calcium (612.7 mg), potassium (442.2 mg), sodium (283.5 mg), magnesium (89.9 mg), zinc (1.9 mg), iron (0.8 mg), manganese (0.3 mg) and aluminum (0.2 mg), respectively. Glutamic acid and aspartic acid were the major amino acids, containing 925.4 and 644.7 mol/g in dried weight, respectively. Fatty acids in Hwangtae were composed of monounsaturated fatty acids, polyunsaturated fatty acids and saturated fatty acids, containing 16.3, 41.2 and 42.5%, respectively. Our results suggested that this Hwangtae, a freeze-dried fish, can be used as a good nutrition source for human health

    PGC-Enriched miRNAs Control Germ Cell Development

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    Controlled release of human growth hormone fused with a human hybrid Fc fragment through a nanoporous polymer membrane

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    Nanotechnology has been applied to the development of more effective and compatible drug delivery systems for therapeutic proteins. Human growth hormone (hGH) was fused with a hybrid Fc fragment containing partial Fc domains of human IgD and IgG(4) to produce a long-acting fusion protein. The fusion protein, hGH-hyFc, resulted in the increase of the hydrodynamic diameter (ca. 11 nm) compared with the diameter (ca. 5 nm) of the recombinant hGH. A diblock copolymer membrane with nanopores (average diameter of 14.3 nm) exhibited a constant release rate of hGH-hyFc. The hGH-hyFc protein released in a controlled manner for one month was found to trigger the phosphorylation of Janus kinase 2 (JAK2) in human B lymphocyte and to exhibit an almost identical circular dichroism spectrum to that of the original hGH-hyFc, suggesting that the released fusion protein should maintain the functional and structural integrity of hGH. Thus, the nanoporous release device could be a potential delivery system for the long-term controlled release of therapeutic proteins fused with the hybrid Fc fragment.X111313sciescopu

    Measurement Invariance of the Internet Addiction Test Among Hong Kong, Japanese, and Malaysian Adolescents

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    There has been increased research examining the psychometric properties on the Internet Addiction Test across different ages and populations. This population-based study examined the psychometric properties using Confirmatory Factory Analysis and measurement invariance using Item Response Theory (IRT) of the IAT in adolescents from three Asian countries. In the Asian Adolescent Risk Behavior Survey (AARBS), 2,535 secondary school students (55.91% girls) in Grade 7 to Grade 13 (Mean age = 15.61 years; SD=1.56) from Hong Kong (n=844), Japan (n=744), and Malaysia (n=947) completed a survey on their Internet use that incorporated the IAT scale. A nested hierarchy of hypotheses concerning IAT cross-country invariance was tested using multi-group confirmatory factor analysis. Replicating past finding in Hong Kong adolescents, the construct of IAT is best represented by a second-order three-factor structure in Malaysian and Japanese adolescents. Configural, metric, scalar, and partial strict factorial invariance was established across the three samples. No cross-country differences on Internet addiction were detected at latent mean level. This study provided empirical support to the IAT as a reliable and factorially stable instrument, and valid to be used across Asian adolescent populations
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