17 research outputs found
Thermoelectric Transport of Massive Dirac Fermions in Bilayer Graphene
Thermoelectric power (TEP) is measured in bilayer graphene for various
temperatures and charge-carrier densities. At low temperatures, measured TEP
well follows the semiclassical Mott formula with a hyperbolic dispersion
relation. TEP for a high carrier density shows a linear temperature dependence,
which demonstrates a weak electron-phonon interaction in the bilayer graphene.
For a low carrier density, a deviation from the Mott relation is observed at
high temperatures and is attributed to the low Fermi temperature in the bilayer
graphene. Oscillating TEP and the Nernst effect for varying carrier density,
observed in a high magnetic field, are qualitatively explained by the two
dimensionality of the system.Comment: published versio
Dependence of quantum-Hall conductance on the edge-state equilibration position in a bipolar graphene sheet
By using four-terminal configurations, we investigated the dependence of
longitudinal and diagonal resistances of a graphene p-n interface on the
quantum-Hall edge-state equilibration position. The resistance of a p-n device
in our four-terminal scheme is asymmetric with respect to the zero point where
the filling factor () of the entire graphene vanishes. This resistance
asymmetry is caused by the chiral-direction-dependent change of the
equilibration position and leads to a deeper insight into the equilibration
process of the quantum-Hall edge states in a bipolar graphene system.Comment: 5 pages, 4 figures, will be published in PR
Breakdown of the interlayer coherence in twisted bilayer graphene
Coherent motion of the electrons in the Bloch states is one of the
fundamental concepts of the charge conduction in solid state physics. In
layered materials, however, such a condition often breaks down for the
interlayer conduction, when the interlayer coupling is significantly reduced by
e.g. large interlayer separation. We report that complete suppression of
coherent conduction is realized even in an atomic length scale of layer
separation in twisted bilayer graphene. The interlayer resistivity of twisted
bilayer graphene is much higher than the c-axis resistivity of Bernal-stacked
graphite, and exhibits strong dependence on temperature as well as on external
electric fields. These results suggest that the graphene layers are
significantly decoupled by rotation and incoherent conduction is a main
transport channel between the layers of twisted bilayer graphene.Comment: 5 pages, 3 figure
Cellular uptake of magnetic nanoparticle is mediated through energy-dependent endocytosis in A549 cells
Biocompatible silica-overcoated magnetic nanoparticles containing an organic fluorescence dye, rhodamine B isothiocyanate (RITC), within a silica shell [50 nm size, MNP@SiO2(RITC)s] were synthesized. For future application of the MNP@SiO2(RITC)s into diverse areas of research such as drug or gene delivery, bioimaging, and biosensors, detailed information of the cellular uptake process of the nanoparticles is essential. Thus, this study was performed to elucidate the precise mechanism by which the lung cancer cells uptake the magnetic nanoparticles. Lung cells were chosen for this study because inhalation is the most likely route of exposure and lung cancer cells were also found to uptake magnetic nanoparticles rapidly in preliminary experiments. The lung cells were pretreated with different metabolic inhibitors. Our results revealed that low temperature disturbed the uptake of magnetic nanoparticles into the cells. Metabolic inhibitors also prevented the delivery of the materials into cells. Use of TEM clearly demonstrated that uptake of the nanoparticles was mediated through endosomes. Taken together, our results demonstrate that magnetic nanoparticles can be internalized into the cells through an energy-dependent endosomal-lysosomal mechanism
Effects of medium chain triglycerides with organic acids on growth performance, fecal score, blood profiles, intestinal morphology, and nutrient digestibility in weaning pigs
Objective: This study was conducted to evaluate the effects of medium chain triglycerides (MCT) with organic acids (OA) on growth performance, fecal score, blood profiles, intestinal morphology, and nutrient digestibility in weaning pigs. Methods: A total of 120 weaning pigs ([YorkshirexLandrace]xDuroc) with an average body weight (BW) of 8.00 +/- 0.87 kg were assigned in five treatments considering sex and initial BW in 3 replications with 8 pigs per pen in a randomized complete block design. The experi-mental diets included a corn-soybean meal based basal diet with or without 0.1% or 0.2% MCT and 0.1% OA. The pigs were fed the diets for 5 weeks (phase 1, 0 to 2 weeks; phase 2, 3 to 5 weeks). A total of 15 barrows with an average BW of 12.48 +/- 0.37 kg were used to evaluate the nutrient digestibility by total collection method. The BW and feed intake were measured at the end of each phase. Blood samples and small intestine samples were collected at the end of each phase, too. Results: Supplementing 0.1% MCT with 0.1% OA showed greater BW for week 5 and average daily gain (ADG) for overall period than control diet. Supplementing 0.1% MCT increased (p<0.05) ADG and improved (p<0.05) gain:feed ratio for phase 1. Dietary MCT and OA did not affect the fecal score and blood concentration of cortisol, immunoglobulin G, tumor necrosis factor-alpha, interleukin-1 beta (IL-1 beta), IL-6, and IL-10 in weaning pigs. Pigs fed the diets with 0.1% MCT had greater (p<0.05) villus height of duodenum and ileum for phase 1. Also, pigs fed the diet with 0.1% OA showed greater (p<0.05) villus height and villus height to crypt depth ratio of duodenum for phase 2. There was no significant difference in nutrient digestibility and nitrogen retention of pigs. Conclusion: Addition of 0.1% MCT with 0.1% OA in weaning pig's diet improved growth performance partly by enhancing intestinal morphology in weaning pigs.N