152 research outputs found
Controlled release of paclitaxel from a self-assembling peptide hydrogel formed in situ and antitumor study in vitro
Background: A nanoscale injectable in situ-forming hydrogel drug delivery system was developed in this study. The system was based on a self-assembling peptide RADA16 solution, which can spontaneously form a hydrogel rapidly under physiological conditions. We used the RADA16 hydrogel for the controlled release of paclitaxel (PTX), a hydrophobic antitumor drug.
Methods: The RADA16-PTX suspension was prepared simply by magnetic stirring, followed by atomic force microscopy, circular dichroism analysis, dynamic light scattering, rheological analysis, an in vitro release assay, and a cell viability test.
Results: The results indicated that RADA16 and PTX can interact with each other and that the amphiphilic peptide was able to stabilize hydrophobic drugs in aqueous solution. The particle size of PTX was markedly decreased in the RADA16 solution compared with its size in water. The RADA16-PTX suspension could form a hydrogel in culture medium, and the elasticity of the hydrogel showed a positive correlation with peptide concentration. In vitro release measurements indicated that hydrogels with a higher peptide concentration had a longer half-release time. The RADA16-PTX hydrogel could effectively inhibit the growth of the breast cancer cell line, MDA-MB-435S, in vitro, and hydrogels with higher peptide concentrations were more effective at inhibiting tumor cell proliferation. The RADA16-PTX hydrogel was effective at controlling the release of PTX and inhibiting tumor cell growth in vitro.
Conclusion: Self-assembling peptide hydrogels may work well as a system for drug delivery
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
Reconfigurable Intelligent Surface Empowered Over-the-Air Federated Edge Learning
Federated edge learning (FEEL) has emerged as a revolutionary paradigm to
develop AI services at the edge of 6G wireless networks as it supports
collaborative model training at a massive number of mobile devices. However,
model communication over wireless channels, especially in uplink model
uploading of FEEL, has been widely recognized as a bottleneck that critically
limits the efficiency of FEEL. Although over-the-air computation can alleviate
the excessive cost of radio resources in FEEL model uploading, practical
implementations of over-the-air FEEL still suffer from several challenges,
including strong straggler issues, large communication overheads, and potential
privacy leakage. In this article, we study these challenges in over-the-air
FEEL and leverage reconfigurable intelligent surface (RIS), a key enabler of
future wireless systems, to address these challenges. We study the
state-of-the-art solutions on RIS-empowered FEEL and explore the promising
research opportunities for adopting RIS to enhance FEEL performance.Comment: This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
Which Channel to Ask My Question? Personalized Customer Service Request Stream Routing using Deep Reinforcement Learning
Customer services are critical to all companies, as they may directly connect
to the brand reputation. Due to a great number of customers, e-commerce
companies often employ multiple communication channels to answer customers'
questions, for example, chatbot and hotline. On one hand, each channel has
limited capacity to respond to customers' requests, on the other hand,
customers have different preferences over these channels. The current
production systems are mainly built based on business rules, which merely
considers tradeoffs between resources and customers' satisfaction. To achieve
the optimal tradeoff between resources and customers' satisfaction, we propose
a new framework based on deep reinforcement learning, which directly takes both
resources and user model into account. In addition to the framework, we also
propose a new deep-reinforcement-learning based routing method-double dueling
deep Q-learning with prioritized experience replay (PER-DoDDQN). We evaluate
our proposed framework and method using both synthetic and a real customer
service log data from a large financial technology company. We show that our
proposed deep-reinforcement-learning based framework is superior to the
existing production system. Moreover, we also show our proposed PER-DoDDQN is
better than all other deep Q-learning variants in practice, which provides a
more optimal routing plan. These observations suggest that our proposed method
can seek the trade-off where both channel resources and customers' satisfaction
are optimal.Comment: 13 pages, 7 figure
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