418 research outputs found
Electro-mechanical dynamics of spiral waves in a discrete 2D model of human atrial tissue
We investigate the effect of mechano-electrical feedback and atrial fibrillation induced electrical remodelling (AFER) of cellular ion channel properties on the dynamics of spiral waves in a discrete 2D model of human atrial tissue. The tissue electro-mechanics are modelled using the discrete element method (DEM). Millions of bonded DEM particles form a network of coupled atrial cells representing 2D cardiac tissue, allowing simulations of the dynamic behaviour of electrical excitation waves and mechanical contraction in the tissue. In the tissue model, each cell is modelled by nine particles, accounting for the features of individual cellular geometry; and discrete inter-cellular spatial arrangement of cells is also considered. The electro-mechanical model of a human atrial single-cell was constructed by strongly coupling the electrophysiological model of Colman et al. to the mechanicalmyofilament model of Rice et al., with parameters modified based on experimental data. A stretch-activated channel was incorporated into the model to simulate the mechano-electrical feedback. In order to investigate the effect of mechano-electrical feedback on the dynamics of spiral waves, simulations of spiral waves were conducted in both the electromechanical model and the electrical-only model in normal and AFER conditions, to allow direct comparison of the results between the models. Dynamics of spiral waves were characterized by tracing their tip trajectories, stability, excitation frequencies and meandering range of tip trajectories. It was shown that the developed DEM method provides a stable and efficient model of human atrial tissue with considerations of the intrinsically discrete and anisotropic properties of the atrial tissue, which are challenges to handle in traditional continuum mechanics models. This study provides mechanistic insights into the complex behaviours of spiral waves and the genesis of atrial fibrillation by showing an important role of the mechano-electrical feedback in facilitating and promoting atrial fibrillation
On the Sweet Spot of Contrastive Views for Knowledge-enhanced Recommendation
In recommender systems, knowledge graph (KG) can offer critical information
that is lacking in the original user-item interaction graph (IG). Recent
process has explored this direction and shows that contrastive learning is a
promising way to integrate both. However, we observe that existing KG-enhanced
recommenders struggle in balancing between the two contrastive views of IG and
KG, making them sometimes even less effective than simply applying contrastive
learning on IG without using KG. In this paper, we propose a new contrastive
learning framework for KG-enhanced recommendation. Specifically, to make full
use of the knowledge, we construct two separate contrastive views for KG and
IG, and maximize their mutual information; to ease the contrastive learning on
the two views, we further fuse KG information into IG in a one-direction
manner.Extensive experimental results on three real-world datasets demonstrate
the effectiveness and efficiency of our method, compared to the
state-of-the-art. Our code is available through the anonymous
link:https://figshare.com/articles/conference_contribution/SimKGCL/2278338
Effects of bolt slippage on the wind induced responses of transmission tower line system
The wind induced responses of transmission tower line system are studied by finite element method. Firstly, a slip model considering eccentricity and bolt joint slippage in diagonal bracings, tower legs and tower head is built by ANSYS. The slip model has a more accurate result compared with conventional models. Secondly, the finite element models of tower line systems are established and the wind speed time histories are simulated using MATLAB. Finally, the wind induced responses of different tower line systems are studied. The results of a single tower and the tower line systems are compared to study the effects of tower-line coupling effects and bolt slippage on wind induced responses of transmission tower line systems
Trajectory Data Collection with Local Differential Privacy
Trajectory data collection is a common task with many applications in our
daily lives. Analyzing trajectory data enables service providers to enhance
their services, which ultimately benefits users. However, directly collecting
trajectory data may give rise to privacy-related issues that cannot be ignored.
Local differential privacy (LDP), as the de facto privacy protection standard
in a decentralized setting, enables users to perturb their trajectories locally
and provides a provable privacy guarantee. Existing approaches to private
trajectory data collection in a local setting typically use relaxed versions of
LDP, which cannot provide a strict privacy guarantee, or require some external
knowledge that is impractical to obtain and update in a timely manner. To
tackle these problems, we propose a novel trajectory perturbation mechanism
that relies solely on an underlying location set and satisfies pure
-LDP to provide a stringent privacy guarantee. In the proposed
mechanism, each point's adjacent direction information in the trajectory is
used in its perturbation process. Such information serves as an effective clue
to connect neighboring points and can be used to restrict the possible region
of a perturbed point in order to enhance utility. To the best of our knowledge,
our study is the first to use direction information for trajectory perturbation
under LDP. Furthermore, based on this mechanism, we present an anchor-based
method that adaptively restricts the region of each perturbed trajectory,
thereby significantly boosting performance without violating the privacy
constraint. Extensive experiments on both real-world and synthetic datasets
demonstrate the effectiveness of the proposed mechanisms.Comment: Accepted by VLDB 202
Krüppel-like factor 8 promotes aerobic glycolysis in prostate cancer cells by regulating AKT/mTOR signaling pathway
Purpose: To investigate the effects of Krüppel-like factor 8 (KLF8) in prostate cancer (PCa) cell viability and glycolysis, and explore its role as a regulatory factor.Methods: Immunoblot assays were conducted to assess the expression of KLF8 and proteins in AKT/mTOR pathway in PCa cell lines PC-3 and DU145. Cell Counting Kit-8 assays were performed to assess the effect of KLF8 on PCa cell viability. The glycolysis capacity of PCa cells was determined by measuring the levels of glucose intake, lactic acid production, and cellular ATP levels.Results: Depletion of KLF8 decreased the survival of PCa cells in vitro (p < 0.05). KLF8 depletion also inhibited aerobic glucose metabolism in PCa cells (p < 0.05). Further studies confirmed that KLF8 contributed to the growth and glycolysis of PCa cells via the regulation of AKT/mTOR pathway.Conclusion: KLF8 regulates glycolysis in PCa cells by regulating AKT/mTOR signaling pathway and is thus a promising therapeutic target for PCa treatment.
Keywords: Krüppel-like factor 8 (KLF8), Prostate cancer (PCa), Aerobic glucose, AKT/mTOR signaling pathway, Therapeutic targe
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