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Zhongxue Yuan,1 Rui Xu,1 Jinquan Li,1 Yueli Chen,1 Binghui Wu,2 Jianghua Feng,1 Zhong Chen1 1Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian, China; 2State Key Laboratory for Physical Chemistry of Solid Surface, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, China Background: Core–shell-structured nanoparticles (NPs) have attracted much scientific attention due to their promising potential in biomedical fields in recent years. However, their underlying mechanisms of action and potential adverse effects following administration remain unknown. Methods: In the present study, a 1H nuclear magnetic resonance-based metabonomic strategy was applied to investigate the metabolic consequences in rats following the intravenous administration of parent NPs of core–shell-structured nanoparticles, Fe3O4@SiO2-NH2 (Fe@Si) NPs. Results: Alterations reflected in plasma and urinary metabonomes indicated that Fe@Si NPs induced metabolic perturbation in choline, ketone-body, and amino-acid metabolism besides the common metabolic disorders in tricarboxylic acid cycle, lipids, and glycogen metabolism often induced by the exogenous agents. Additionally, intestinal flora metabolism and the urea cycle were also influenced by Fe@Si NP exposure. Time-dependent biological effects revealed obvious metabolic regression, dose-dependent biological effects implied different biochemical mechanisms between low- and high-dose Fe@Si NPs, and size-dependent biological effects provided potential windows for size optimization. Conclusion: Nuclear magnetic resonance-based metabonomic analysis helps in understanding the biological mechanisms of Fe@Si NPs, provides an identifiable ground for the selection of view windows, and further serves the clinical translation of Fe@Si NP-derived and -modified bioprobes or bioagents. Keywords: core&nda

Zhongxue Yuan,1 Rui Xu,1 Jinquan Li,1 Yueli Chen,1 Binghui Wu,2 Jianghua Feng,1 Zhong Chen1 1Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian, China; 2State Key Laboratory for Physical Chemistry of Solid Surface, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, China Background: Core–shell-structured nanoparticles (NPs) have attracted much scientific attention due to their promising potential in biomedical fields in recent years. However, their underlying mechanisms of action and potential adverse effects following administration remain unknown. Methods: In the present study, a 1H nuclear magnetic resonance-based metabonomic strategy was applied to investigate the metabolic consequences in rats following the intravenous administration of parent NPs of core–shell-structured nanoparticles, Fe3O4@SiO2-NH2 (Fe@Si) NPs. Results: Alterations reflected in plasma and urinary metabonomes indicated that Fe@Si NPs induced metabolic perturbation in choline, ketone-body, and amino-acid metabolism besides the common metabolic disorders in tricarboxylic acid cycle, lipids, and glycogen metabolism often induced by the exogenous agents. Additionally, intestinal flora metabolism and the urea cycle were also influenced by Fe@Si NP exposure. Time-dependent biological effects revealed obvious metabolic regression, dose-dependent biological effects implied different biochemical mechanisms between low- and high-dose Fe@Si NPs, and size-dependent biological effects provided potential windows for size optimization. Conclusion: Nuclear magnetic resonance-based metabonomic analysis helps in understanding the biological mechanisms of Fe@Si NPs, provides an identifiable ground for the selection of view windows, and further serves the clinical translation of Fe@Si NP-derived and -modified bioprobes or bioagents. Keywords: core&nda

In this paper, we propose an adaptive beam that adapts its divergence angle according to the receiver aperture diameter and the communication distance to improve the received power and ease the alignment between the communicating optical transceivers in a free-space optical communications (FSOC) system for high-speed trains (HSTs). We compare the received power, signal-to-noise ratio, bit error rate, and the maximum communication distance of the proposed adaptive beam with a beam that uses a fixed divergence angle of 1 mrad. The proposed adaptive beam yields a higher received power with an increase of 33 dB in average over the fixed-divergence beam under varying visibility conditions and distance. Moreover, the proposed adaptive divergence angle extends the communication distance of a FSOC system for HSTs to about three times under different visibility conditions as compared to a fixed divergence beam. We also propose a new ground transceiver placement that places the ground transceivers of a FSOC system for HSTs on gantries placed above the train passage instead of placing them next to track. The proposed transceiver placement provides a received-power increase of 3.8 dB in average over the conventional placement of ground-station transceivers next to the track.

A train backbone network consists of a sequence of nodes arranged in a linear topology. A key step that enables communication in such a network is that of topology discovery, or train inauguration, whereby nodes learn in a distributed fashion the physical topology of the backbone network. While the current standard for train inauguration assumes wired links between adjacent backbone nodes, this work investigates the more challenging scenario in which the nodes communicate wirelessly. The key motivations for this desired switch from wired topology discovery to wireless one are the flexibility and capability for expansion and upgrading of a wireless backbone. The implementation of topology discovery over wireless channels is made difficult by the broadcast nature of the wireless medium, and by fading and interference. A novel topology discovery protocol is proposed that overcomes these issues and requires relatively minor changes to the wired standard. The protocol is shown via analysis and numerical results to be robust to the impairments caused by the wireless channel including interference from other trains., Comment: To appear on IEEE Transactions on Intelligent Transportation Systems