810 research outputs found
Magnonic band structure of domain wall magnonic crystals
Magnonic crystals are prototype magnetic metamaterials designed for the
control of spin wave propagation. Conventional magnonic crystals are composed
of single domain elements. If magnetization textures, such as domain walls,
vortices and skyrmions, are included in the building blocks of magnonic
crystals, additional degrees of freedom over the control of the magnonic band
structure can be achieved. We theoretically investigate the influence of domain
walls on the spin wave propagation and the corresponding magnonic band
structure. It is found that the rotation of magnetization inside a domain wall
introduces a geometric vector potential for the spin wave excitation. The
corresponding Berry phase has quantized value , where is the
winding number of the domain wall. Due to the topological vector potential, the
magnonic band structure of magnonic crystals with domain walls as comprising
elements differs significantly from an identical magnonic crystal composed of
only magnetic domains. This difference can be utilized to realize dynamic
reconfiguration of magnonic band structure by a sole nucleation or annihilation
of domain walls in magnonic crystals.Comment: 21 pages, 9 figure
Bayesian Inversion with Neural Operator (BINO) for Modeling Subdiffusion: Forward and Inverse Problems
Fractional diffusion equations have been an effective tool for modeling
anomalous diffusion in complicated systems. However, traditional numerical
methods require expensive computation cost and storage resources because of the
memory effect brought by the convolution integral of time fractional
derivative. We propose a Bayesian Inversion with Neural Operator (BINO) to
overcome the difficulty in traditional methods as follows. We employ a deep
operator network to learn the solution operators for the fractional diffusion
equations, allowing us to swiftly and precisely solve a forward problem for
given inputs (including fractional order, diffusion coefficient, source terms,
etc.). In addition, we integrate the deep operator network with a Bayesian
inversion method for modelling a problem by subdiffusion process and solving
inverse subdiffusion problems, which reduces the time costs (without suffering
from overwhelm storage resources) significantly. A large number of numerical
experiments demonstrate that the operator learning method proposed in this work
can efficiently solve the forward problems and Bayesian inverse problems of the
subdiffusion equation
Tetra-μ-benzoato-κ8 O:O′-bis[(benzoic acid-κO)nickel(II)]
The title compound, [Ni2(C7H5O2)4(C7H6O2)2], is composed of two NiII ions, four bridging benzoate anions and two η1-benzoic acid molecules. The [Ni2(PhCOO)4] unit adopts a typical paddle-wheel conformation. The center between the two NiII atoms represents a crystallographic center of inversion. In addition, each NiII ion also coordinates to one O atom from a benzoic acid molecule. The crystal packing is realised by intermolecular hydrogen-bonding interactions and π–π stacking interactions, with a centroid–centroid distance of 3.921 (1) Å
3-[(R)-3,3-Dichloro-2-hydroxypropyl]-8-hydroxy-6-methoxy-1H-isochromen-1-one
The title compound, C13H12Cl2O5, is an isocoumarin compound which has been isolated from the ethyl acetate extract of the fermentation broth of actinomycete Streptomyces sp. (V4) from the South China Sea. There are intra- and intermolecular hydrogen bonds and halogen bonds [Cl⋯Cl = 3.434 (2) Å; C—Cl⋯Cl = 121.6°]. The intermolecular O—H⋯O hydrogen bonds link molecules into chains along the b axis
(3E,5E)-3,5-Bis(4-hydroxy-3,5-dimethoxybenzylidene)oxan-4-one monohydrate
In the title compound, C23H24O8·H2O, the six-membered ring of the oxan-4-one (tetrahydropyran-4-one) ring displays an envelope conformation with the heterocyclic O atom at the flap position. The dihedral angles between the terminal benzene rings is 37.23 (10)°. Classical intermolecular O—H⋯O and weak C—H⋯O hydrogen bonds are present in the crystal structure
Perivascular adipose tissue (PVAT) in atherosclerosis: a double-edged sword
Abstract
Perivascular adipose tissue (PVAT), the adipose tissue that surrounds most of the vasculature, has emerged as an active component of the blood vessel wall regulating vascular homeostasis and affecting the pathogenesis of atherosclerosis. Although PVAT characteristics resemble both brown and white adipose tissues, recent evidence suggests that PVAT develops from its own distinct precursors implying a closer link between PVAT and vascular system. Under physiological conditions, PVAT has potent anti-atherogenic properties mediated by its ability to secrete various biologically active factors that induce non-shivering thermogenesis and metabolize fatty acids. In contrast, under pathological conditions (mainly obesity), PVAT becomes dysfunctional, loses its thermogenic capacity and secretes pro-inflammatory adipokines that induce endothelial dysfunction and infiltration of inflammatory cells, promoting atherosclerosis development. Since PVAT plays crucial roles in regulating key steps of atherosclerosis development, it may constitute a novel therapeutic target for the prevention and treatment of atherosclerosis. Here, we review the current literature regarding the roles of PVAT in the pathogenesis of atherosclerosis.https://deepblue.lib.umich.edu/bitstream/2027.42/145729/1/12933_2018_Article_777.pd
Cold quark matter in a quasiparticle model: thermodynamic consistency and stellar properties
The strong coupling in the effective quark mass was usually taken as a
constant in a quasiparticle model while it is, in fact, running with an energy
scale. With a running coupling, however, the thermodynamic inconsistency
problem appears in the conventional treatment. We show that the renormalization
subtraction point should be taken as a function of the summation of the
biquadratic chemical potentials if the quark's current masses vanish, in order
to ensure full thermodynamic consistency. Taking the simplest form, we study
the properties of up-down () quark matter, and confirm that the revised
quasiparticle model fulfills the quantitative criteria for thermodynamic
consistency. Moreover, we find that the maximum mass of an quark star can
be larger than two times the solar mass, reaching up to , for
reasonable model parameters. However, to further satisfy the upper limit of
tidal deformability observed in the event
GW170817, the maximum mass of an quark star can only be as large as
, namely . In other words,
our results indicate that the measured tidal deformability for event GW170817
places an upper bound on the maximum mass of quark stars, but which does
not rule out the possibility of the existence of quark stars composed of
quark matter, with a mass of about two times the solar mass.Comment: 10 pages, 8 figure
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