Synthesis of multifunctional nanoparticles for imaging and enhancement in therapy

The purpose of this work was to synthesize nanoparticles composed of high atomic number elements and semiconductor material in a core/shell structure for the potential to be used as enhancers for radiotherapy as well as luminescence imaging platforms. Additionally, to quantify their role in free radical production after exposure to ionizing radiation through chemical routes. Spherical gold nanoparticles were synthesized via a citrate stabilizer method. Two sizes of 12nm and 25 nm gold spheres were used as the cores for the europium-doped gadolinium vanadate flower-shaped shell. The production of 7-hydroxycoumarin-3-carboxylic acid in an aqueous environment upon kV irradiation of its precursor, coumarin-3-carboxylic acid, was assessed and used as a fluorescence detector for hydroxyl radicals. The quantification of excess or moderation of hydroxyl radicals in the presence of the nanomaterial as compared to a control sample can indicate the potential for increased DNA damage for purposes such as tumor control. This work indicates the potential for physical and chemical enhancement in the presence of nanomaterials

Special Issue on Body Area Networks

info:eu-repo/semantics/publishedVersio

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical-layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical-layer message authentication is also introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201