5,264 research outputs found
(Z)-Ethyl 3-(2,4-difluoroanilino)-2-(4-methoxyphenyl)acrylate
The title compound, C18H17F2NO3, consists of three individually planar subunits, namely two benzene rings and one aminoacrylate group. The aminoacrylate group forms dihedral angles of 5.92 (7) and 50.21 (6)° with the difluoro and methoxy benzene rings, respectively. The dihedral angle between the two benzene rings is 55.25 (7)°. The molecules exhibit intramolecular N—H⋯O and N—H⋯F interactions and form a three-dimensional network via intermolecular C—H⋯O and C—H⋯π hydrogen bonds
General stationary charged black holes as charged particle accelerators
We study the possibility of getting infinite energy in the center of mass
frame of colliding charged particles in a general stationary charged black
hole. For black holes with two-fold degenerate horizon, it is found that
arbitrary high center-of-mass energy can be attained, provided that one of the
particle has critical angular momentum or critical charge, and the remained
parameters of particles and black holes satisfy certain restriction. For black
holes with multiple-fold degenerate event horizons, the restriction is
released. For non-degenerate black holes, the ultra-high center-of-mass is
possible to be reached by invoking the multiple scattering mechanism. We obtain
a condition for the existence of innermost stable circular orbit with critical
angular momentum or charge on any-fold degenerate horizons, which is essential
to get ultra-high center-of-mass energy without fine-tuning problem. We also
discuss the proper time spending by the particle to reach the horizon and the
duality between frame dragging effect and electromagnetic interaction. Some of
these general results are applied to braneworld small black holes.Comment: 23 pages, no figures, revised version accepted for publication in
Phys. Rev.
(E)-2-(4-Methoxyphenyl)-N-(2-pyridyl)-3-(2-pyridylamino)acrylamide
In the title compound, C20H18N4O2, the aminoacrylamide group makes a dihedral angles of 4.0 (1)° with the amino-bound pyridyl ring and 15.66 (12)° with the amide-bound pyridyl ring. The dihedral angle between the aminoacrylamide group and the pendant 4-methoxyphenyl group is 71.22 (9)°. In the crystal structure, N—H⋯N hydrogen bonds and C—H⋯O and C—H⋯N interactions help to establish the packing. Intramolecular C—H⋯O and C—H⋯(N,O) contacts also occur
Speech Enhancement with Multi-granularity Vector Quantization
With advances in deep learning, neural network based speech enhancement (SE)
has developed rapidly in the last decade. Meanwhile, the self-supervised
pre-trained model and vector quantization (VQ) have achieved excellent
performance on many speech-related tasks, while they are less explored on SE.
As it was shown in our previous work that utilizing a VQ module to discretize
noisy speech representations is beneficial for speech denoising, in this work
we therefore study the impact of using VQ at different layers with different
number of codebooks. Different VQ modules indeed enable to extract
multiple-granularity speech features. Following an attention mechanism, the
contextual features extracted by a pre-trained model are fused with the local
features extracted by the encoder, such that both global and local information
are preserved to reconstruct the enhanced speech. Experimental results on the
Valentini dataset show that the proposed model can improve the SE performance,
where the impact of choosing pre-trained models is also revealed
1-(2-Hydroxy-3,4-dimethoxyphenyl)-2-(4-methoxyphenyl)ethanone
In the title compound, C17H18O5, the pyrogallol group is almost coplanar with the mean plane of the attached carbonyl group [dihedral angle of 1.95 (13)°] and makes a dihedral angle of 56.01 (10)° with the other benzene ring. Of the three methoxy groups, only one is significantly twisted relative to its attached benzene ring [C—O—C—C torsion angles of 4.0 (5), 3.9 (6) and −106.3 (4)°]. Intramolecular O—H⋯O and C—H⋯O hydrogen bonds help to establish the conformation, and the packing is consolidated by C—H⋯O interactions and π–π stacking interactions [centroid–centroid separation = 3.735 (2) Å]
Effects of Compound Danshen tablets on spatial cognition and expression of brain β-amyloid precursor protein in a rat model of alzheimer's disease
AbstractObjectiveTo observe the effects of Compound Danshen Tablets (CDST) on spatial cognition and expression of brain b-amyloid precursor protein (β-APP) in a rat model of Alzheimer's disease.MethodsThe rat model of Alzheimer's disease (AD) was established using D-galactose to cause subacute aging combined with Meynert nucleus damage. Rat behavior was monitored using the Morris water maze, and the expression of β-APP in rat brain tissue was detected via immunohistochemistry.ResultsCDST significantly improved spatial cognition and decreased β-APP expression in the cortex and hippocampus (P<0.05, P<0.01).ConclusionsCDST can significantly improve spatial cognition in a rat model of AD. This observation is possibly related to a reduction in β-APP expression in the rat brain
Memory augment is All You Need for image restoration
Image restoration is a low-level vision task, most CNN methods are designed
as a black box, lacking transparency and internal aesthetics. Although some
methods combining traditional optimization algorithms with DNNs have been
proposed, they all have some limitations. In this paper, we propose a
three-granularity memory layer and contrast learning named MemoryNet,
specifically, dividing the samples into positive, negative, and actual three
samples for contrastive learning, where the memory layer is able to preserve
the deep features of the image and the contrastive learning converges the
learned features to balance. Experiments on Derain/Deshadow/Deblur task
demonstrate that these methods are effective in improving restoration
performance. In addition, this paper's model obtains significant PSNR, SSIM
gain on three datasets with different degradation types, which is a strong
proof that the recovered images are perceptually realistic. The source code of
MemoryNet can be obtained from https://github.com/zhangbaijin/MemoryNe
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