201 research outputs found
Magnon Mediated Electric Current Drag Across a Ferromagnetic Insulator Layer
In a semiconductor hererostructure, the Coulomb interaction is responsible
for the electric current drag between two 2D electron gases across an electron
impenetrable insulator. For two metallic layers separated by a ferromagnetic
insulator (FI) layer, the electric current drag can be mediated by a
nonequilibrium magnon current of the FI. We determine the drag current by using
the semiclassical Boltzmann approach with proper boundary conditions of
electrons and magnons at the metal-FI interface.Comment: 13 pages, 2 figures: to appear in PR
Kondo Resonance in the Presence of Spin-Polarized Currents
We propose an improved method of the equation of motion approach to study the
Kondo problem in spin-dependent non-equilibrium conditions. We find that the
previously introduced additional renormalization for non-equilibrium Kondo
effects is not required when we use a proper decoupling scheme. Our improved
formulation is then applied to address the spin-split Kondo peaks when a spin
current injects into a Kondo system.Comment: 4+ pages, 4 eps figure
Infrared spectroscopy of small-molecule endofullerenes
Hydrogen is one of the few molecules which has been incarcerated in the
molecular cage of C and forms endohedral supramolecular complex
H@C. In this confinement hydrogen acquires new properties. Its
translational motion becomes quantized and is correlated with its rotations. We
applied infrared spectroscopy to study the dynamics of hydrogen isotopologs
H, D and HD incarcerated in C. The translational and rotational
modes appear as side bands to the hydrogen vibrational mode in the mid infrared
part of the absorption spectrum. Because of the large mass difference of
hydrogen and C and the high symmetry of C the problem is
identical to a problem of a vibrating rotor moving in a three-dimensional
spherical potential. The translational motion within the C cavity breaks
the inversion symmetry and induces optical activity of H. We derive
potential, rotational, vibrational and dipole moment parameters from the
analysis of the infrared absorption spectra. Our results were used to derive
the parameters of a pairwise additive five-dimensional potential energy surface
for H@C. The same parameters were used to predict H energies
inside C[Xu et al., J. Chem. Phys., {\bf 130}, 224306 (2009)]. We
compare the predicted energies and the low temperature infrared absorption
spectra of H@C.Comment: Updated author lis
A self-consistent treatment of non-equilibrium spin torques in magnetic multilayers
It is known that the transfer of spin angular momenta between current
carriers and local moments occurs near the interface of magnetic layers when
their moments are non-collinear. However, to determine the magnitude of the
transfer, one should calculate the spin transport properties far beyond the
interface regions. Based on the spin diffusion equation, we present a
self-consistent approach to evaluate the spin torque for a number of layered
structures. One of the salient features is that the longitudinal and transverse
components of spin accumulations are inter-twined from one layer to the next,
and thus, the spin torque could be significantly amplified with respect to
treatments which concentrate solely on the transport at the interface due to
the presence of the much longer longitudinal spin diffusion length. We conclude
that bare spin currents do not properly estimate the spin angular momentum
transferred between to the magnetic background; the spin transfer that occurs
at interfaces should be self-consistently determined by embedding it in our
globally diffuse transport calculations.Comment: 21 pages, 6 figure
Confirming a predicted selection rule in inelastic neutron scattering spectroscopy: the quantum translator-rotator H2 entrapped inside C60
We report an inelastic neutron scattering (INS) study of H2 molecule encapsulated inside the fullerene C60 which confirms the recently predicted selection rule, the first to be established for the INS spectroscopy of aperiodic, discrete molecular compounds. Several transitions from the ground state of para-H2 to certain excited translation-rotation states, forbidden according to the selection
rule, are systematically absent from the INS spectra, thus validating the selection rule with a high degree of confidence. Its confirmation sets a precedent, as it runs counter to the widely held view that the INS spectroscopy of molecular compounds is not subject to any selection rules
Functional analysis of the C-reactive protein (CRP) gene -717A>G polymorphism associated with coronary heart disease
<p>Abstract</p> <p>Background</p> <p>Atherosclerosis underlies the major pathophysiological mechanisms of coronary heart disease (CHD), and inflammation contributes to all phases of atherosclerosis. C-reactive protein (CRP), a sensitive, but nonspecific marker of inflammation has been shown to play proatherogenic roles in the process of atherosclerosis. Our previous report showed that rs2794521 (-717A>G), located in the promoter of the CRP gene, was independently associated with CHD in Chinese subjects. In the present study, we tried to investigate the biological significance of this genetic variation <it>in vitro</it>.</p> <p>Methods</p> <p>The influence of G to A substitution at the site of rs2794521 on the transcriptional activity of the promoter of the CRP gene was assessed by luciferase reporter assay, and protein binding to the site of rs2794521 was detected by EMSA assay.</p> <p>Results</p> <p>The G to A exchange at the site of rs2794521 resulted in an increased transcriptional activity of the promoter of CRP gene, and glucocorticoid receptor (GR) protein factor bound drastically differently to the A and G alleles at the site of rs2794521.</p> <p>Conclusion</p> <p>These results provided functional evidence supporting the association of the SNP rs2794521 of the CRP gene with CHD probably through regulating the expression level of CRP by different variations of rs2794521.</p
Association between polymorphisms in the coagulation factor VII gene and coronary heart disease risk in different ethnicities: a meta-analysis
<p>Abstract</p> <p>Background</p> <p>Previous studies have examined the association between polymorphisms in the coagulation factor VII gene and the risk of coronary heart disease (CHD), but those studies have been inconclusive. This study was conducted to assess the associations between these polymorphisms and CHD and evaluated the associations in different ethnicities.</p> <p>Methods</p> <p>Literature-based searching was conducted to collect data and two methods, namely fixed-effects and random-effects, were performed to pool the odds ratio (OR), together with the 95% confidence interval (CI). Publication bias and between-study heterogeneity were also examined.</p> <p>Results</p> <p>Thirty-nine case-control studies of the three polymorphisms, R353Q (rs6046), HVR4 and -323Ins10 (rs36208070) in factor VII gene and CHD were enrolled in this meta-analysis, including 9,151 cases of CHD and 14,099 controls for R353Q, 2,863 cases and 2,727 controls for HVR4, and 2,862 cases and 4,240 controls for -323Ins10. Significant association was only found in Asian population for R353Q (Q vs R), with pooled OR of 0.70(95%CI: 0.55, 0.90). For the -323Ins10 polymorphism (10 vs 0), we found significant associations in both Asian and European populations, with pooled ORs of 0.74(95%CI: 0.61, 0.88) and 0.63(95%CI: 0.53, 0.74), respectively. Marginal significant association was found between HVR4 (H7 vs H5+H6) and CHD (OR = 0.88, 95% CI: 0.78, 1.00). There was no evidence of publication bias, but between-study heterogeneity was found in the analyses.</p> <p>Conclusions</p> <p>The -323Ins10 polymorphism in factor VII gene is significantly associated with CHD in both Asian and European populations, while R353Q polymorphism showed trend for association with CHD in Asians. Lack of association was found for HVR4 polymorphism. Further studies are needed to confirm the association, especially for -323Ins10 polymorphism.</p
- …