111 research outputs found
The dependence of the structure of planet-opened gaps in protoplanetary disks on radiative cooling
Planets can excite density waves and open annular gas gaps in protoplanetary
disks. The depth of gaps is influenced by the evolving angular momentum carried
by density waves. While the impact of radiative cooling on the evolution of
density waves has been studied, a quantitative correlation to connect gap depth
with the cooling timescale is lacking. To address this gap in knowledge, we
employ the grid-based code Athena++ to simulate disk-planet interactions,
treating cooling as a thermal relaxation process. We establish quantitative
dependences of steady-state gap depth (Eq. 36) and width (Eq. 41) on planetary
mass, Shakura-Sunyaev viscosity, disk scale height, and thermal relaxation
timescale . We confirm previous results that gap opening is the
weakest when thermal relaxation timescale is comparable to local dynamical
timescale. Significant variations in gap depth, up to an order of magnitude,
are found with different . In terms of width, a gap is at its narrowest
around , approximately to narrower compared to the
isothermal case. When , it can be wider, and higher
viscosity enhances this effect. We derive possible masses of the gas
gap-opening planets in AS 209, HD 163296, MWC 480, and HL Tau, accounting for
the uncertainties in local thermal relaxation timescale.Comment: 19 pages, 16 figures, 4 tables, accepted for publication in Ap
A Heterogeneous Parallel Non-von Neumann Architecture System for Accurate and Efficient Machine Learning Molecular Dynamics
This paper proposes a special-purpose system to achieve high-accuracy and
high-efficiency machine learning (ML) molecular dynamics (MD) calculations. The
system consists of field programmable gate array (FPGA) and application
specific integrated circuit (ASIC) working in heterogeneous parallelization. To
be specific, a multiplication-less neural network (NN) is deployed on the
non-von Neumann (NvN)-based ASIC (SilTerra 180 nm process) to evaluate atomic
forces, which is the most computationally expensive part of MD. All other
calculations of MD are done using FPGA (Xilinx XC7Z100). It is shown that, to
achieve similar-level accuracy, the proposed NvN-based system based on low-end
fabrication technologies (180 nm) is 1.6x faster and 10^2-10^3x more energy
efficiency than state-of-the-art vN based MLMD using graphics processing units
(GPUs) based on much more advanced technologies (12 nm), indicating superiority
of the proposed NvN-based heterogeneous parallel architecture
Learning to Check Contract Inconsistencies
Contract consistency is important in ensuring the legal validity of the
contract. In many scenarios, a contract is written by filling the blanks in a
precompiled form. Due to carelessness, two blanks that should be filled with
the same (or different)content may be incorrectly filled with different (or
same) content. This will result in the issue of contract inconsistencies, which
may severely impair the legal validity of the contract. Traditional methods to
address this issue mainly rely on manual contract review, which is
labor-intensive and costly. In this work, we formulate a novel Contract
Inconsistency Checking (CIC) problem, and design an end-to-end framework,
called Pair-wise Blank Resolution (PBR), to solve the CIC problem with high
accuracy. Our PBR model contains a novel BlankCoder to address the challenge of
modeling meaningless blanks. BlankCoder adopts a two-stage attention mechanism
that adequately associates a meaningless blank with its relevant descriptions
while avoiding the incorporation of irrelevant context words. Experiments
conducted on real-world datasets show the promising performance of our method
with a balanced accuracy of 94.05% and an F1 score of 90.90% in the CIC
problem.Comment: Accepted by AAAI 202
A Novel Inhibitory Mechanism of Mitochondrion-Dependent Apoptosis by a Herpesviral Protein
Upon viral infection, cells undergo apoptosis as a defense against viral replication. Viruses, in turn, have evolved elaborate mechanisms to subvert apoptotic processes. Here, we report that a novel viral mitochondrial anti-apoptotic protein (vMAP) of murine γ-herpesvirus 68 (γHV-68) interacts with Bcl-2 and voltage-dependent anion channel 1 (VDAC1) in a genetically separable manner. The N-terminal region of vMAP interacted with Bcl-2, and this interaction markedly increased not only Bcl-2 recruitment to mitochondria but also its avidity for BH3-only pro-apoptotic proteins, thereby suppressing Bax mitochondrial translocation and activation. In addition, the central and C-terminal hydrophobic regions of vMAP interacted with VDAC1. Consequently, these interactions resulted in the effective inhibition of cytochrome c release, leading to the comprehensive inhibition of mitochondrion-mediated apoptosis. Finally, vMAP gene was required for efficient γHV-68 lytic replication in normal cells, but not in mitochondrial apoptosis-deficient cells. These results demonstrate that γHV-68 vMAP independently targets two important regulators of mitochondrial apoptosis-mediated intracellular innate immunity, allowing efficient viral lytic replication
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Efficient and bright warm-white electroluminescence from lead-free metal halides.
Solution-processed metal-halide perovskites are emerging as one of the most promising materials for displays, lighting and energy generation. Currently, the best-performing perovskite optoelectronic devices are based on lead halides and the lead toxicity severely restricts their practical applications. Moreover, efficient white electroluminescence from broadband-emission metal halides remains a challenge. Here we demonstrate efficient and bright lead-free LEDs based on cesium copper halides enabled by introducing an organic additive (Tween, polyethylene glycol sorbitan monooleate) into the precursor solutions. We find the additive can reduce the trap states, enhancing the photoluminescence quantum efficiency of the metal halide films, and increase the surface potential, facilitating the hole injection and transport in the LEDs. Consequently, we achieve warm-white LEDs reaching an external quantum efficiency of 3.1% and a luminance of 1570 cd m-2 at a low voltage of 5.4 V, showing great promise of lead-free metal halides for solution-processed white LED applications
DeePMD-kit v2: A software package for Deep Potential models
DeePMD-kit is a powerful open-source software package that facilitates
molecular dynamics simulations using machine learning potentials (MLP) known as
Deep Potential (DP) models. This package, which was released in 2017, has been
widely used in the fields of physics, chemistry, biology, and material science
for studying atomistic systems. The current version of DeePMD-kit offers
numerous advanced features such as DeepPot-SE, attention-based and hybrid
descriptors, the ability to fit tensile properties, type embedding, model
deviation, Deep Potential - Range Correction (DPRc), Deep Potential Long Range
(DPLR), GPU support for customized operators, model compression, non-von
Neumann molecular dynamics (NVNMD), and improved usability, including
documentation, compiled binary packages, graphical user interfaces (GUI), and
application programming interfaces (API). This article presents an overview of
the current major version of the DeePMD-kit package, highlighting its features
and technical details. Additionally, the article benchmarks the accuracy and
efficiency of different models and discusses ongoing developments.Comment: 51 pages, 2 figure
Alterations in Spontaneous Neuronal Activity and Microvascular Density of the Optic Nerve Head in Active Thyroid-Associated Ophthalmopathy
PurposeTo investigate changes in local spontaneous brain activity in patients with active thyroid-associated ophthalmopathy (TAO) and explore the relationship between such alterations and microvascular indices.MethodsThirty-six active TAO patients with active phase and 39 healthy controls (HCs) were enrolled in this study. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI), neuropsychological tests, and ophthalmological examinations. The rs-fMRI-based fractional low-frequency fluctuation amplitude (fALFF) analysis methods were used to assess spontaneous brain activity in both groups. The structure (peripapillary retinal nerve fiber layer, pRNFL) and microvascular indices (the optic nerve head (ONH) whole image vessel density, ONH-wiVD, and peripapillary vessel density) were analyzed through optical coherence tomographic angiography imaging. The relationship between abnormal spontaneous brain activity and ophthalmological indices was analyzed using the Spearman’s rank correlation analysis.ResultsCompared with HCs, active TAO patients had increased fALFF in the right inferior temporal gyrus (R.ITG) and left posterior cingulate gyrus (L.PCC), but decreased fALFF in the right calcarine (R.CAL). The fALFF values in L.PCC were positively correlated with peripapillary vessel density, whereas fALFF values in R.CAL were negatively related to peripapillary vessel density.ConclusionsThis study demonstrates that changes in spontaneous brain activity of active TAO are accompanied by peripapillary microvascular variations. These results provide insights into the pathophysiological mechanisms of active TAO. In addition, the combination of fALFF values and peripapillary vessel density may be served as important references for better clinical decision making
The Ubiquitin/Proteasome System Mediates Entry and Endosomal Trafficking of Kaposi's Sarcoma-Associated Herpesvirus in Endothelial Cells
Ubiquitination, a post-translational modification, mediates diverse cellular functions including endocytic transport of molecules. Kaposi's sarcoma-associated herpesvirus (KSHV), an enveloped herpesvirus, enters endothelial cells primarily through clathrin-mediated endocytosis. Whether ubiquitination and proteasome activity regulates KSHV entry and endocytosis remains unknown. We showed that inhibition of proteasome activity reduced KSHV entry into endothelial cells and intracellular trafficking to nuclei, thus preventing KSHV infection of the cells. Three-dimensional (3-D) analyses revealed accumulation of KSHV particles in a cytoplasmic compartment identified as EEA1+ endosomal vesicles upon proteasome inhibition. KSHV particles are colocalized with ubiquitin-binding proteins epsin and eps15. Furthermore, ubiquitination mediates internalization of both KSHV and one of its receptors integrin β1. KSHV particles are colocalized with activated forms of the E3 ligase c-Cbl. Knock-down of c-Cbl or inhibition of its phosphorylation reduced viral entry and intracellular trafficking, resulting in decreased KSHV infectivity. These results demonstrate that ubiquitination mediates internalization of both KSHV and one of its cognate receptors integrin β1, and identify c-Cbl as a potential E3 ligase that facilitates this process
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