893 research outputs found
Coupled Reversible and Irreversible Bistable Switches Underlying TGF-\beta-induced Epithelial to Mesenchymal Transition
Epithelial to mesenchymal transition (EMT) plays important roles in embryonic
development, tissue regeneration and cancer metastasis. While several feedback
loops have been shown to regulate EMT, it remains elusive how they coordinately
modulate EMT response to TGF-\beta treatment. We construct a mathematical model
for the core regulatory network controlling TGF-\beta-induced EMT. Through
deterministic analyses and stochastic simulations, we show that EMT is a
sequential two-step program that an epithelial cell first transits to partial
EMT then to the mesenchymal state, depending on the strength and duration of
TGF-\beta stimulation. Mechanistically the system is governed by coupled
reversible and irreversible bistable switches. The SNAIL1/miR-34 double
negative feedback loop is responsible for the reversible switch and regulates
the initiation of EMT, while the ZEB/miR-200 feedback loop is accountable for
the irreversible switch and controls the establishment of the mesenchymal
state. Furthermore, an autocrine TGF-\beta/miR-200 feedback loop makes the
second switch irreversible, modulating the maintenance of EMT. Such coupled
bistable switches are robust to parameter variation and molecular noise. We
provide a mechanistic explanation on multiple experimental observations. The
model makes several explicit predictions on hysteretic dynamic behaviors,
system response to pulsed stimulation and various perturbations, which can be
straightforwardly tested.Comment: 32 pages, 8 figures, accepted by Biophysical Journa
CFLIT: Coexisting Federated Learning and Information Transfer
Future wireless networks are expected to support diverse mobile services,
including artificial intelligence (AI) services and ubiquitous data
transmissions. Federated learning (FL), as a revolutionary learning approach,
enables collaborative AI model training across distributed mobile edge devices.
By exploiting the superposition property of multiple-access channels,
over-the-air computation allows concurrent model uploading from massive devices
over the same radio resources, and thus significantly reduces the communication
cost of FL. In this paper, we study the coexistence of over-the-air FL and
traditional information transfer (IT) in a mobile edge network. We propose a
coexisting federated learning and information transfer (CFLIT) communication
framework, where the FL and IT devices share the wireless spectrum in an OFDM
system. Under this framework, we aim to maximize the IT data rate and guarantee
a given FL convergence performance by optimizing the long-term radio resource
allocation. A key challenge that limits the spectrum efficiency of the
coexisting system lies in the large overhead incurred by frequent communication
between the server and edge devices for FL model aggregation. To address the
challenge, we rigorously analyze the impact of the computation-to-communication
ratio on the convergence of over-the-air FL in wireless fading channels. The
analysis reveals the existence of an optimal computation-to-communication ratio
that minimizes the amount of radio resources needed for over-the-air FL to
converge to a given error tolerance. Based on the analysis, we propose a
low-complexity online algorithm to jointly optimize the radio resource
allocation for both the FL devices and IT devices. Extensive numerical
simulations verify the superior performance of the proposed design for the
coexistence of FL and IT devices in wireless cellular systems.Comment: The paper has been accepted for publication by IEEE Transactions on
Wireless Communications (March 2023
- …