- Biolectromagnetic Interaction
Bioelectromagnetic (BEM) interactions are, in our vision, complex phenomena, which can not be studied without a vision of the problem integrating different spatial and time scales. Consequently, several theoretical approaches must be available, suitable for the different scales, and they must be unified into a unique methodological pathway.
Whilst FDTD is the elcted tool at whole-body level, for more microscopic systems Markov models are adopted. More specifically, at ionic channel level, state-machine models are suitable to simulate BEM interactions, with an effective possibility to investigate both energetical perturbations of the conformational mapping of the channel, as well as sensibl sites for BEM interactions at macromolecular scales.
Models are available for the most important voltage-dependent and ligand-dependentchannels, both in a sham condition and EM-exposed. Furthermore, investigations are performed, combining the use of Markov models with fractal theory and stochastic resonance approaches.
The combination of FDTD and stochastic approaches at macromolecular scales is an example of modelling integration representing an attractive approach for a complete BEM characterization of the response of biological systems to EM stimulation.
- Human-antenna interaction with FDTD
The rapid diffusion of wireless technologies focuses the attention on the potential risks for human health due to the exposure to electromagnetic fields.
Among the several EM sources, a particular interest has been addressed, till now, to cellular phones, whilst a much smaller emphasis has been reserved to radiobase station antennas (RBAs). Nonetheless, the exposure to the near-field of such devices is a relevant issue for a large class of workers, spending long daily time intervals in the proximity of RBAs (for instance, employees involved in radio-communication apparata installation and maintenance, or working over building roofs hosting RBAs).
The NF interaction between RBAs and humans is a difficult problem. It could be attacked with experimental approaches, using homogeneous or simplified human phantoms (human body models). A numerical solution, on the other hand, is potentially attractive, because of the several accurate numerical phantoms developed in the recent past, and the large variety of rigorous numerical EM techniques proposed in the literature.
Unfortunately, a numerical accurate solution is quite hard, because of the huge computational effort required. In fact, in many cases, panel RBAs have a leading dimension D of nearly 2 meters, with consequent far-field distances which can easily reach 10-20 meters.
Therefore, the use of a full-wave solver, necessary for a rigorous NF analysis, is unaffordable with standard computational techniques. In such a framework, a Parallel Variable Grid Finite Difference Time Domain Method has been developed, able to give a numerical rigorous solution to the RBA-human Near Field interaction problem.
Several relevant problems can be afforded, such as:
- a) the characterization of RBAs
- b) the evaluation of dosimetric parameters in a human subject exposed to a RBA and the consequent potential health risks
- c) the evaluation of the accuracy of experimental apparata, using for instance the homogeneous phantom approximation
- d) the evaluation of the accuracy of simplified approaches, using the far-field approximation.
- e) the Specific Absorption Rate (SAR) dependence on the human shape and inner characterization