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Satellite communication networks are expected to be indispensable as part of an integrated complement for the upcoming 5G networks since they can provide the most comprehensive coverage and reliable connection for areas where are economically unviable and/or difficult to deploy terrestrial infrastructures. Meanwhile, the power-domain non-orthogonal multiple access (NOMA), which can serve multiple users simultaneously within the same time/frequency block, has been viewed as another promising strategy used in the 5G network to provide high spectral efficiency and resource utilization. In this paper, we introduce a general overview of the application of the NOMA to various satellite architectures for the benefits of meeting the availability, coverage, and efficiency requirements targeted by the 5G. The fundamental and ubiquitous features of satellite link budget are first reviewed. Then, the advantage and benefit of introducing the NOMA scheme in various satellite architectures, such as conventional downlink/uplink satellite networks, cognitive satellite terrestrial networks, and cooperative satellite networks with satellite/terrestrial relays, are provided, along with the motivation and research methodology for each scenario. Finally, this paper reviews the potential directions for future research.INDEX TERMS Power-domain non-orthogonal multiple access, satellite networks, cognitive satellite terrestrial networks, cooperative satellite terrestrial networks, 5G.

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The fish brain plays an important role in controlling growth, development, reproduction, and adaptation to environmental change. However, few studies stem from the perspective of whole transcriptome change in a fish brain and its response to long-term hypersaline stress. This study compares the differential transcriptomic responses of juvenile Nile tilapia (Oreochromis niloticus) maintained for 8 weeks in brackish water (16 practical salinity units, psu) and in freshwater. Fish brains from each treatment were collected for RNA-seq analysis to identify potential genes and pathways responding to hypersaline stress. A total of 27,089 genes were annotated, and 391 genes were expressed differently in the salinity treatment. Ten pathways containing 40 differentially expressed genes were identified in the tilapia brain. Antigen processing and presentation and phagosome were the two principally affected pathways in the immune system. Thirty-one of 40 genes were involved in various expressions associated with environmental information processing pathways such as neuroactive ligand-receptor interaction, cytokine-cytokine receptor interaction, the Jak-STAT signaling pathway, cell adhesion molecules (CAMs), and the PI3K-Akt signaling pathway, which are the upstream pathways for modulation of immunity and osmoregulation. The most-changed genes (>5-fold) were all down-regulated, including four growth hormone/prolactin gene families, i.e., prolactin precursor (−10.62), prolactin-1 (−11), somatotropin (−10.15), somatolactin-like (−6.18), and two other genes [thyrotropin subunit beta (−7.73) and gonadotropin subunit beta-2 (−5.06)] that stimulated prolactin release in tilapia. The downregulation pattern of these genes corroborates the decrease in tilapia immunity with increasing salinity and reveals an adaptive mechanism of tilapia to long-term hypersaline stress. Ovarian steroidogenesis, isoquinoline alkaloid biosynthesis, and phenylalanine metabolism are the three important pathways in the response of the fish to long-term hypersaline stress. This study has identified several pathways and relevant genes that are involved in salinity regulation in a euryhaline fish and provides insight into understanding regulatory mechanisms of fish to salinity change.

Lanthanide doped upconversion nanoparticles reveal enormous potential for biomedical applications. However, they are limited by low upconversion efficiency. In this paper, we demonstrate tip-enhanced upconversion luminescence (UCL) from a single Yb3+–Er3+-codoped NaYF4 nanoparticle with a maximum enhancement factor of 11 by the plasmonic effect, which is a solution for improving the conversion efficiency and will become a potential technique for the applications in sensitive imaging and detection via speeding up both the absorption and the emission processes of lanthanide doped upconversion nanoparticles. By investigating the optical properties of the tip-enhanced UCL at 550 and 660 nm separately in Yb3+–Er3+-codoped NaYF4 nanoparticles, we observe that the gold-coated tip influences the upconversion process in Yb3+–Er3+-codoped NaYF4 particles by improving the reception and the transmission of incident electromagnetic fields.

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Real-time traffic speed is indispensable for many ITS applications, such as traffic-aware route planning and eco-driving advisory system. Existing traffic speed estimation solutions assume vehicles travel along roads using constant speed. However, this assumption does not hold due to traffic dynamicity and can potentially lead to inaccurate estimation in real world. In this paper, we propose a novel in-network traffic speed estimation approach using infrastructure-free vehicular networks. The proposed solution utilizes macroscopic traffic flow model to estimate the traffic condition. The selected model only relies on vehicle density, which is less likely to be affected by the traffic dynamicity. In addition, we also demonstrate an application of the proposed solution in real-time route planning applications. Extensive evaluations using both traffic trace based large scale simulation and testbed based implementation have been performed. The results show that our solution outperforms some existing ones in terms of accuracy and efficiency in traffic-aware route planning applications.