A survey of underwater wireless optical communication

Underwater wireless communication refers to transmitting data in unguided water environment through the use of wireless carriers, i.e., radio-frequency wave, acoustic wave, and optical wave. We focus, in this thesis, on the underwater wireless optical communication (UWOC) that employs optical wave as the transmission carriers. In comparison to RF and acoustic counterparts, UWOC has a much higher transmission bandwidth, thus providing much higher data rate. Due to this high-speed transmission advantage, UWOC has attracted considerable attention in recent years. Many potential applications of UWOC systems have been proposed for environmental monitoring, offshore exploration, disaster precaution, and military operations. However, UWOC systems also suffer from severe absorption and scattering introduced by underwater channel. In order to overcome these technical challenges, several new system design approaches, which are different from the conventional terrestrial free-space optical communication, have been explored in recent years. In this thesis, we provide a comprehensive survey of the state-of-the-art of UWOC research in three aspects: channel characterization, channel modulation and coding techniques, and practical implementations of UWOC. Based on the comprehensive understanding of UWOC, we also investigate the outage performance for vertical buoy-based UWOC with pointing errors. Closed-form outage probability with zero boresight pointing errors and outage probability bounds with nonzero boresight pointing errors have been derived.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat

Biochanin A Promotes Proliferation that Involves a Feedback Loop of MicroRNA-375 and Estrogen Receptor Alpha in Breast Cancer Cells

Background: Biochanin A and formononetin are O-methylated isoflavones that are isolated from the root of Astragalus membranaceus, and have antitumorigenic effects. Our previous studies found that formononetin triggered growth-inhibitory and apoptotic activities in MCF-7 breast cancer cells. We performed in vivo and in vitro studies to further investigate the potential effect of biochanin A in promoting cell proliferation in estrogen receptor (ER)-positive cells, and to elucidate underlying mechanisms. Methods: ERα-positive breast cancer cells (T47D, MCF-7) were treated with biochanin A. The MTT assay and flow cytometry were used to assess cell proliferation and apoptosis. mRNA levels of ERα, Bcl-2, and miR-375 were quantified using real-time polymerase chain reaction. Compared with the control, low biochanin A concentrations (2-6 μM) stimulated ERα-positive cell proliferation (T47D, MCF-7). The more sensitive T47D cells were used to study the relevant signaling pathway. Results: After treatment with biochanin A, ERα, miR-375, and Bcl-2 expression was significantly upregulated. Additionally, in the in vivo studies, uterine weight in ovariectomized mice treated with biochanin A increased significantly. Conclusion: This study demonstrated that biochanin A promoted ERα-positive cell proliferation through miR-375 activation and this mechanism is possibly involving in a miR-375 and ERα feedback loop

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30° rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high energy electron diffraction,ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth

MOESM2 of Polyphenolic glycosides isolated from Pogostemon cablin (Blanco) Benth. as novel influenza neuraminidase inhibitors

Additional file 2. The data of NA inhibition experiments