2,220 research outputs found
Mechanism of Polarization Fatigue in BiFeO3: the Role of Schottky Barrier
By using piezoelectric force microscopy and scanning Kelvin probe microscopy,
we have investigated the domain evolution and space charge distribution in
planar BiFeO3 capacitors with different electrodes. It is observed that charge
injection at the film/electrode interface leads to domain pinning and
polarization fatigue in BiFeO3. Furthermore, the Schottky barrier at the
interface is crucial for the charge injection process. Lowering the Schottky
barrier by using low work function metals as the electrodes can also improve
the fatigue property of the device, similar to what oxide electrodes can
achieve
NCGNN: Node-level Capsule Graph Neural Network
Message passing has evolved as an effective tool for designing Graph Neural
Networks (GNNs). However, most existing works naively sum or average all the
neighboring features to update node representations, which suffers from the
following limitations: (1) lack of interpretability to identify crucial node
features for GNN's prediction; (2) over-smoothing issue where repeated
averaging aggregates excessive noise, making features of nodes in different
classes over-mixed and thus indistinguishable. In this paper, we propose the
Node-level Capsule Graph Neural Network (NCGNN) to address these issues with an
improved message passing scheme. Specifically, NCGNN represents nodes as groups
of capsules, in which each capsule extracts distinctive features of its
corresponding node. For each node-level capsule, a novel dynamic routing
procedure is developed to adaptively select appropriate capsules for
aggregation from a subgraph identified by the designed graph filter.
Consequently, as only the advantageous capsules are aggregated and harmful
noise is restrained, over-mixing features of interacting nodes in different
classes tends to be avoided to relieve the over-smoothing issue. Furthermore,
since the graph filter and the dynamic routing identify a subgraph and a subset
of node features that are most influential for the prediction of the model,
NCGNN is inherently interpretable and exempt from complex post-hoc
explanations. Extensive experiments on six node classification benchmarks
demonstrate that NCGNN can well address the over-smoothing issue and
outperforms the state of the arts by producing better node embeddings for
classification
A new metric for rotating charged Gauss-Bonnet black holes in AdS spaces
This paper presents a new metric for slowly rotating charged Gauss-Bonnet
black holes in higher dimensional anti-de Sitter spaces. Taking the angular
momentum parameter up to second order, the slowly rotating charged black
hole solutions are obtained by working directly in the action.Comment: 11 pages and accepted by Chin. Phys.
Thermodynamics of third order Lovelock anti-de Sitter black holes revisited
We compute the mass and the temperature of third order Lovelock black holes
with negative Gauss-Bonnet coefficient in anti-de Sitter space and
perform the stability analysis of topological black holes. When , the
third order Lovelock black holes are thermodynamically stable for the whole
range . When , we found that the black hole has an intermediate
unstable phase for . In eight dimensional spacetimes, however, a new phase
of thermodynamically unstable small black holes appears if the coefficient
is under a critical value. For , black holes have
similar the distributions of thermodynamically stable regions to the case where
the coefficient is under a critical value for . It is
worth to mention that all the thermodynamic and conserved quantities of the
black holes with flat horizon don't depend on the Lovelock coefficients and are
the same as those of black holes in general gravity.Comment: 15 pages, 22 figure
Black holes in Einstein-dilaton-Massive gravity
In this paper, we focus on the Einstein-dilaton-Massive (EdM) gravity
including the coupling of dilaton scalar field to massive graviton terms, and
then derive static and spherically symmetric solutions of dilatonic black holes
in four dimensional spacetime. We discover that the dilatonic black hole could
possess two horizons (event and cosmological), extreme (Nariai) and naked
singularity black holes for the suitably fixed parameters. Moreover, the
dilatonic black hole solutions are neither asymptotic flat nor (A)dS in the
appearance of coupling of the dilaton field. In addition, we investigate
thermodynamic properties of these dilatonic black holes, and check the
corresponding first law of black hole thermodynamics. Extending to the EdM
gravity in high dimensions, we further obtain the dilatonic black hole
solutions in () dimensional spacetime.Comment: 17 pages, 6 figure
Nuclear Factor Erythroid 2-Related Factor 2 Deficiency Results in Amplification of the Liver Fat-Lowering Effect of Estrogen
Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates multiple biologic processes, including hepatic lipid metabolism. Estrogen exerts actions affecting energy homeostasis, including a liver fat-lowering effect. Increasing evidence indicates the crosstalk between these two molecules. The aim of this study was to evaluate whether Nrf2 modulates estrogen signaling in hepatic lipid metabolism. Nonalcoholic fatty liver disease (NAFLD) was induced in wild-type and Nrf2-null mice fed a high-fat diet and the liver fat-lowering effect of exogenous estrogen was subsequently assessed. We found that exogenous estrogen eliminated 49% and 90% of hepatic triglycerides in wild-type and Nrf2-null mice with NAFLD, respectively. This observation demonstrates that Nrf2 signaling is antagonistic to estrogen signaling in hepatic fat metabolism; thus, Nrf2 absence results in striking amplification of the liver fat-lowering effect of estrogen. In addition, we found the association of trefoil factor 3 and fatty acid binding protein 5 with the liver fat-lowering effect of estrogen. In summary, we identified Nrf2 as a novel and potent inhibitor of estrogen signaling in hepatic lipid metabolism. Our finding may provide a potential strategy to treat NAFLD by dually targeting Nrf2 and estrogen signaling
Interictal magnetoencephalographic findings related with surgical outcomes in lesional and nonlesional neocortical epilepsy
Purpose: To investigate whether interictal magnetoencephalography (MEG) concordant with other techniques can predict surgical outcome in patients with lesional and nonlesional refractory neocortical epilepsy (NE).
Methods: 23 Patients with lesional NE and 20 patients with nonlesional NE were studied. MEG was recorded for all patients with a 275 channel whole-head system. Synthetic aperture magnetometry (SAM) with excess kurtosis (g2) and conventional Equivalent Current Dipole (ECD) were used for MEG data analysis. 27 Patients underwent long-term extraoperative intracranial video electroencephalography (iVEEG) monitoring. Surgical outcomes were assessed based on more than 1-year of post-surgical follow-up using Engel classification system.
Results: As we expected, both favorable outcomes (Engel class I or II) and seizure freedom outcomes (Engel class IA) were higher for the concordance condition (MEG findings are concordant with MRI or iVEEG findings) versus the discordance condition. Also the seizure free rate was significantly higher (x2 = 5.24, P \u3c 0.05) for the patients with lesional NE than for the patients with nonlesional NE. In 30% of the patients with nonlesional NE, the MEG findings proved to be valuable for intracranial electrode implantation.
Conclusions: This study demonstrates that a favorable post-surgical outcome can be obtained in most patients with concordant MEG and MRI results even without extraoperative iVEEG monitoring, which indicates that the concordance among different modalities could indicate a likelihood of better postsurgical outcomes. However, extraoperative iVEEG monitoring remains prerequisite to the patients with discordant MEG and MRI findings. For nonlesional cases, our results showed that MEG could provide critical information in the placement of intracranial electrodes
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