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We describe a genetic algorithm approach to solve an inverse problem in optics, which determines the characteristics of a fiber Bragg grating from its reflected spectrum. The validity of the proposed method is demonstrated by use of a Bragg sensor for the measurement of nonlinear strain acting on a uniaxial aluminum test specimen.

Recently, optical fibre Bragg gratings have attracted a significant amount of attention as optical fibre sensors for measuring strain in composite structures. Indeed, the growth of optical fibre technology has spurred the development of smart composites capable of measuring real-time internal strain within structures and an assortment of measurands such as temperature, pressure and chemical. In this paper, optical fibre Bragg grating sensors are embedded in a novel fibre-metal laminate composite, to demonstrate the potential of fibre Bragg grating sensors in measuring post-processing residual strain within a multimaterial structure. Repeated impact tests in the region of the grating have been performed to investigate the survivability of the sensor. In addition, post-impact sensor linearity tests have then been carried out to evaluate the sensor response to load.

Cortical neurons grown on multielectrode array (MEA) chips have been shown to be a valuable alternative method to study electrophysiological properties of the central nervous system neurons and to perform functional toxicological screening. Here we studied the effects of binary mixtures on neuronal networks cultured on MEAs. We have considered compounds with similar and different mode-of-action (MoA) to characterize and assess their combined effects. Individual and binary mixture dose-response curves based on spontaneous neuronal activity have been generated and the IC(50) has been considered as the end-point for neurotoxicity assessment. The two classical approaches of mixtures toxicity studies: concentration addition (CA) and independent action (IA) have been applied to compare calculated and experimental results. Nuclear magnetic resonance (NMR) spectroscopy has been employed to confirm no chemical reaction or complexation between mixtures components. The results suggest that both CA and IA are able to predict the toxicity of the mixture and that the combination of in vitro test methods with theoretical dose-response models has a strong potential as an alternative tool for the prediction of mixtures neurotoxicity.