7,332 research outputs found
First-principles LDA+U and GGA+U study of neptunium dioxide
We have performed a systematic first-principles investigation to calculate
the electronic structures, mechanical properties, and phonon dispersion curves
of NpO. The local density approximation and the generalized gradient
approximation formalisms have been used to account for the strong on-site
Coulomb repulsion among the localized Np electrons. By choosing the
Hubbard \emph{U} parameter around 4 eV, the orbital occupancy characters of Np
5\emph{f} and O 2\emph{p} are in good agreement with recent experiments [J.
Nucl. Mater. \textbf{389}, 470 (2009)]. Comparing with our previous study of
ThO, we note that stronger covalency exists in NpO due to the more
localization behavior of 5\emph{f} electrons of Np in line with the
localization-delocalization trend exhibited by the actinides series.Comment: 7 pages, 6 figure
Mast cells and metabolic syndrome
AbstractMast cells are critical effectors in the development of allergic diseases and in many immunoglobulin E-mediated immune responses. These cells exert their physiological and pathological activities by releasing granules containing histamine, cytokines, chemokines, and proteases, including mast cell-specific chymase and tryptase. Like macrophages and T lymphocytes, mast cells are inflammatory cells, and they participate in the pathogenesis of inflammatory diseases such as cardiovascular complications and metabolic disorders. Recent observations suggested that mast cells are involved in insulin resistance and type 2 diabetes. Data from animal models proved the direct participation of mast cells in diet-induced obesity and diabetes. Although the mechanisms by which mast cells participate in these metabolic diseases are not fully understood, established mast cell pathobiology in cardiovascular diseases and effective mast cell inhibitor medications used in pre-formed obesity and diabetes in experimental models offer hope to patients with these common chronic inflammatory diseases. This article is part of a Special Issue entitled: Mast cells in inflammation
On A Proper Definition of Spin Current
The conventional definition of spin current is incomplete and unphysical in
describing spin transport in systems with spin-orbit coupling. A proper and
measurable spin current is established in this study, which fits well into the
standard framework of near-equilibrium transport theory and has the desirable
property to vanish in insulators with localized orbitals. Experimental
implications of our theory are discussed.Comment: Final version with updated journal-re
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