A novel system for the imaging of optical multipaths

The use of diffuse and line of sight optical radiation for wireless communications is an area of growing interest. In diffuse optical communications systems, light takes multiple paths from source to detector. Therefore knowledge of these multipaths is crucial to design of communications systems. In order to measure the characteristics of the optical channels a.novel imaging system that records the frequency response of the indoor optical channel has been developed. The system uses a swept frequency laser source to illuminate the room and a large aperture telescope that concentrates incoming radiation onto a photomultiplier to receive it. Scanning of the receiver telescope yields data for all angles of arrival, allowing the angle-dependent frequency response to be obtained. Subsequent processing, using Fourier transform or superresolution techniques yields images of the arriving optical multipaths. In this paper the construction and characteristics of the imaging system are introduced. Frequency response measurements of a particular space, up to 750MHz, corresponding to approximately 1.5ns time resolution, are presented, together with images of light propagating within the coverage area

The application of microfluidic devices for viral diagnosis in developing countries

Whilst diseases such as diabetes and cardiovascular disorders are increasing in the developed world, the main threat to global health remains viral-based infectious disease. Such diseases are notably prevalent in developing countries, where they represent a major cause of mortality; however, their detection and prevention is typically hampered by poor infrastructure and a lack of resources to support the sophisticated diagnostic tools commonly found in modern laboratories. Microfluidic-based diagnostics has the potential to close the gap between developed and developing world medical needs due to the robustness and reduced operating costs such technology offers. The most recent developments in microfluidic diagnostics for viral infections have explored the separation and enumeration of immune cells, the capture and identification of viral particles, and antiviral drug evaluation within microchannels and chambers. Advances in solid-phase separation, isothermal amplification, real-time detection of nucleotide products, and improved efficiency of detection systems in microfluidic platforms have also opened up opportunities for diagnostic innovation. This chapter reviews the potential capability microfluidic technology can offer in addressing the practical challenges of providing diagnostic technology for developing countries, illustrated by research on key viral diseases