252 research outputs found
Magneto-optical properties of multilayer graphenes
The magneto-optical absorption properties of graphene multilayers are
theoretically studied. It is shown that the spectrum can be decomposed into
sub-components effectively identical to the monolayer or bilayer graphene,
allowing us to understand the spectrum systematically as a function of the
layer number. Odd-layered graphenes always exhibit absorption peaks which
shifts in proportion to sqrt(B), with B being the magnetic field, due to the
existence of an effective monolayer-like subband. We propose a possibility of
observing the monolayer-like spectrum even in a mixture of multilayer graphene
films with various layers numbers.Comment: 9 pages, 7 figure
Pairing anti-halo effect
We discuss pairing correlations in weakly bound neutron rich nuclei, by using
the coordinate-space Hartree-Fock-Bogolyubov approach which allows to take
properly into account the coupling to particle continuum. We show that the
additional pairing binding energy acts against a development of an infinite rms
radius, even in situations when an l=0 single-particle orbital becomes unbound.Comment: 10 RevTeX pages, 3 EPS figure
Magneto-Optical Studies of Exciton Effects in Layer-Type Semiconductors
Both experimental and theoretical works were performed with particular reference to a layer-type semiconductor, GaSe, for a coherent treatment of the exciton-like and the oscillatory Landau-like spectra appearing in a form of their combination in semiconductors in magnetic fields. The interband magneto-absorption and the Faraday rotation were measured in pulsed magnetic fields up to ïœ200 kOe at low temperatures. The theoretical analysis was based mainly on the exact solution for an extremely anisotropic semiconductor in the magnetic field of arbitrary intensity. The exciton effects are discussed in terms of the energy spectrum, the spectral intensity, and the spectral width by the use of the band parameters deduced from the experimental results
Hope Agency and Hope Pathways as Potential Mediators of Trauma Exposure and Psychological Adjustment in Emerging Adults
The present study examined hope as a mediator between trauma exposure and negative affective conditions in 490 college students. Hope agency, but not hope pathways, mediated some of the association. Trauma exposure maintained a significant association with negative affective conditions. Implications for counselors working with trauma-exposed college students are discussed
A Pulse Compression Ultrasonic Test Instrument and Its Applications
In recent years, so called âdigital ultrasonic test instrumentsâ have been commercially available. These conventional instruments employ electrical impulse excitation of ultrasonic probes. In this configuration, waveforms of ultrasonic pulses into a test object are determined only by the characteristics of probes. This means that variation of probe characteristics causes variation of evaluated results and reproducibility of evaluation is poor. Furthermore, some of the conventional instruments do not provide enough information required for quantitative nondestructive evaluation (QNDE) about a test object, since ultrasonic echo signals are A/D converted after an envelope detector in a receiver and only information of echo height and position is obtained
New Discrete Basis for Nuclear Structure Studies
A complete discrete set of spherical single-particle wave functions for
studies of weakly-bound many-body systems is proposed. The new basis is
obtained by means of a local-scale point transformation of the spherical
harmonic oscillator wave functions. Unlike the harmonic oscillator states, the
new wave functions decay exponentially at large distances. Using the new basis,
characteristics of weakly-bound orbitals are analyzed and the ground state
properties of some spherical doubly-magic nuclei are studied. The basis of the
transformed harmonic oscillator is a significant improvement over the harmonic
oscillator basis, especially in studies of exotic nuclei where the coupling to
the particle continuum is important.Comment: 13 pages, RevTex, 6 p.s. figures, submitted to Phys. Rev.
Nuclear Skins and Halos in the Mean-Field Theory
Nuclei with large neutron-to-proton ratios have neutron skins, which manifest
themselves in an excess of neutrons at distances greater than the radius of the
proton distribution. In addition, some drip-line nuclei develop very extended
halo structures. The neutron halo is a threshold effect; it appears when the
valence neutrons occupy weakly bound orbits. In this study, nuclear skins and
halos are analyzed within the self-consistent Skyrme-Hartree-Fock-Bogoliubov
and relativistic Hartree-Bogoliubov theories for spherical shapes. It is
demonstrated that skins, halos, and surface thickness can be analyzed in a
model-independent way in terms of nucleonic density form factors. Such an
analysis allows for defining a quantitative measure of the halo size. The
systematic behavior of skins, halos, and surface thickness in even-even nuclei
is discussed.Comment: 22 RevTeX pages, 22 EPS figures included, submitted to Physical
Review
A case of post-transplant adult T-cell leukemia/lymphoma presenting myelopathy similar to but distinct from human T-cell leukemia virus type I (HTLV- I)-associated myelopathy
Expression of chemokine receptors on peripheral blood lymphocytes in multiple sclerosis and neuromyelitis optica
<p>Abstract</p> <p>Background</p> <p>The role of different chemokine receptors in the pathogenesis of multiple sclerosis (MS) has been extensively investigated; however, little is known about the difference in the role of chemokine receptors between the pathogenesis of neuromyelitis optica (NMO) and MS. Therefore, we examined the expression of chemokine receptors on peripheral blood lymphocytes (PBL) in MS and NMO.</p> <p>Methods</p> <p>We used flow cytometry to analyse lymphocyte subsets in 12 patients with relapsing NMO, 24 with relapsing-remitting MS during relapse, 3 with NMO and 5 with MS during remission.</p> <p>Results</p> <p>Compared with healthy controls (HC), the percentage of lymphocytes in white blood cells was significantly lower in NMO and MS patients. The percentage of T cells expressing CD4<sup>+</sup>CD25<sup>+ </sup>and CD4<sup>+</sup>CD45RO<sup>+ </sup>was higher, while that of CD4<sup>+</sup>CC chemokine receptor (CCR)3<sup>+ </sup>(T helper 2, Th2) was significantly lower in MS patients than in HC. The ratios of CD4<sup>+</sup>CXC chemokine receptors (CXCR)3<sup>+</sup>/CD4<sup>+</sup>CCR3<sup>+ </sup>(Th1/Th2) and CD8<sup>+</sup>CXCR3<sup>+</sup>/CD8<sup>+</sup>CCR4<sup>+ </sup>(T cytotoxic 1, Tc1/Tc2) were higher in MS patients than in HC. The percentage of CD8<sup>+</sup>CXCR3<sup>+ </sup>T cell (Tc1) and CD4<sup>+</sup>CXCR3<sup>+ </sup>T cell (Th1) decreased significantly during remission in MS patients (<it>P <</it>0.05). No significant differences were identified in the expression of the chemokine receptors on PBL in NMO patients compared with MS patients and HC.</p> <p>Conclusions</p> <p>Th1 dominance of chemokine receptors on blood T cells and the correlation between CXCR3<sup>+ </sup>T cell (Th1 and Tc1) and disease activity in MS patients were confirmed by analysing chemokines receptors on PBL. In contrast, deviation in the Th1/Th2 balance was not observed in NMO patients.</p
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