389 research outputs found
Suppression of backward scattering of Dirac fermions in iron pnictides Ba(FeRuAs)
We report electronic transport of Dirac cones when Fe is replaced by Ru,
which has an isoelectronic electron configuration to Fe, using single crystals
of Ba(FeRuAs). The electronic transport of parabolic bands is
shown to be suppressed by scattering due to the crystal lattice distortion and
the impurity effect of Ru, while that of the Dirac cone is not significantly
reduced due to the intrinsic character of Dirac cones. It is clearly shown from
magnetoresistance and Hall coefficient measurements that the inverse of average
mobility, proportional to cyclotron effective mass, develops as the square root
of the carrier number (n) of the Dirac cones. This is the unique character of
the Dirac cone linear dispersion relationship. Scattering of Ru on the Dirac
cones is discussed in terms of the estimated mean free path using experimental
parameters.Comment: 6 pages, 3 figures, To be published in Phys. Rev.
Magnetic moment of the 2083 keV level of [140]Ce
For the magnetic moment of the 2083 keV level of [140]Ce, there are four published data, all obtained by applying an external magnetic field of less than 5 T to a liquid sample containing [140]La using the time-differential perturbed angular correlation (TDPAC) technique. Although these four values are consistent within two times their uncertainties (2σ), the range of values in 2σ extends from μ=+3.0to +5.2 (in units of nuclear magneton, μ[N]). This time, the TDPAC technique was successfully applied to the 2083 keV level of 140Ce implanted in an Fe foil. The magnetic moment of this level was determined to be μ=+4.00(20)μ[N], employing the known hyperfine field at 141Ce in Fe, −41(2) T, which agrees very well with one of the values, μ=+4.06(15)μ[N]. The present value is compared with two shell-model calculations
Detection of diurnal variation of tomato transcriptome through the molecular timetable method in a sunlight-type plant factory
The timing of measurement during plant growth is important because many genes are expressed periodically and orchestrate physiological events. Their periodicity is generated by environmental fluctuations as external factors and the circadian clock as the internal factor. The circadian clock orchestrates physiological events such as photosynthesis or flowering and it enables enhanced growth and herbivory resistance. These characteristics have possible applications for agriculture. In this study, we demonstrated the diurnal variation of the transcriptome in tomato (Solanum lycopersicum) leaves through molecular timetable method in a sunlight-type plant factory. Molecular timetable methods have been developed to detect periodic genes and estimate individual internal body time from these expression profiles in mammals. We sampled tomato leaves every 2 h for 2 days and acquired time-course transcriptome data by RNA-Seq. Many genes were expressed periodically and these expressions were stable across the 1st and 2nd days of measurement. We selected 143 time-indicating genes whose expression indicated periodically, and estimated internal time in the plant from these expression profiles. The estimated internal time was generally the same as the external environment time; however, there was a difference of more than 1 h between the two for some sampling points. Furthermore, the stress-responsive genes also showed weakly periodic expression, implying that they were usually expressed periodically, regulated by light–dark cycles as an external factor or the circadian clock as the internal factor, and could be particularly expressed when the plant experiences some specific stress under agricultural situations. This study suggests that circadian clock mediate the optimization for fluctuating environments in the field and it has possibilities to enhance resistibility to stress and floral induction by controlling circadian clock through light supplement and temperature control
First-Principles Electronic Structure of Solid Picene
To explore the electronic structure of the first aromatic superconductor,
potassium-doped solid picene which has been recently discovered by Mitsuhashi
et al with the transition temperatures K, we have obtained a
first-principles electronic structure of solid picene as a first step toward
the elucidation of the mechanism of the superconductivity. The undoped crystal
is found to have four conduction bands, which are characterized in terms of the
maximally localized Wannier orbitals. We have revealed how the band structure
reflects the stacked arrangement of molecular orbitals for both undoped and
doped (Kpicene) cases, where the bands are not rigid. The Fermi surface for
Kpicene is a curious composite of a warped two-dimensional surface and a
three-dimensional one.Comment: 5 pages, 4 figure
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C-Reactive Protein Causes Insulin Resistance in Mice Through Fcγ Receptor IIB–Mediated Inhibition of Skeletal Muscle Glucose Delivery
Elevations in C-reactive protein (CRP) are associated with an increased risk of insulin resistance. Whether CRP plays a causal role is unknown. Here we show that CRP transgenic mice and wild-type mice administered recombinant CRP are insulin resistant. Mice lacking the inhibitory Fcγ receptor IIB (FcγRIIB) are protected from CRP-induced insulin resistance, and immunohistochemistry reveals that FcγRIIB is expressed in skeletal muscle microvascular endothelium and is absent in skeletal muscle myocytes, adipocytes, and hepatocytes. The primary mechanism in glucose homeostasis disrupted by CRP is skeletal muscle glucose delivery, and CRP attenuates insulin-induced skeletal muscle blood flow. CRP does not impair skeletal muscle glucose delivery in FcγRIIB−/− mice or in endothelial nitric oxide synthase knock-in mice with phosphomimetic modification of Ser1176, which is normally phosphorylated by insulin signaling to stimulate nitric oxide–mediated skeletal muscle blood flow and glucose delivery and is dephosphorylated by CRP/FcγRIIB. Thus, CRP causes insulin resistance in mice through FcγRIIB-mediated inhibition of skeletal muscle glucose delivery
Role of dynamic Jahn-Teller distortions in Na2C60 and Na2CsC60 studied by NMR
Through 13C NMR spin lattice relaxation (T1) measurements in cubic Na2C60, we
detect a gap in its electronic excitations, similar to that observed in
tetragonal A4C60. This establishes that Jahn-Teller distortions (JTD) and
strong electronic correlations must be considered to understand the behaviour
of even electron systems, regardless of the structure. Furthermore, in metallic
Na2CsC60, a similar contribution to T1 is also detected for 13C and 133Cs NMR,
implying the occurence of excitations typical of JT distorted C60^{2-} (or
equivalently C60^{4-}). This supports the idea that dynamic JTD can induce
attractive electronic interactions in odd electron systems.Comment: 3 figure
Electron-phonon interaction in C70
The matrix elements of the deformation potential of C are calculated
by means of a simple, yet accurate solution of the electron-phonon coupling
problem in fullerenes, based on a parametrization of the ground state
electronic density of the system in terms of hybridized orbitals.
The value of the calculated dimensionless total electron-phonon coupling
constant is , an order of magnitude smaller than in
C, consistent with the lack of a superconducting phase transition in
CA fullerite, and in overall agreement with measurements of the
broadening of Raman peaks in CK. We also calculate the photoemission
cross section of C, which is found to display less structure than that
associated with C, in overall agreement with the experimental
findings.Comment: To be published in Phys. Rev.
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