A preliminary approach to intelligent x-ray imaging for baggage inspection at airports

Identifying explosives in baggage at airports relies on being able to characterize the materials that make up an X-ray image. If a suspicion is generated during the imaging process (step 1), the image data could be enhanced by adapting the scanning parameters (step 2). This paper addresses the first part of this problem and uses textural signatures to recognize and characterize materials and hence enabling system control. Directional Gabor-type filtering was applied to a series of different X-ray images. Images were processed in such a way as to simulate a line scanning geometry. Based on our experiments with images of industrial standards and our own samples it was found that different materials could be characterized in terms of the frequency range and orientation of the filters. It was also found that the signal strength generated by the filters could be used as an indicator of visibility and optimum imaging conditions predicted

On the effect of long-term electrical stimulation on three-dimensional cell cultures: Hen embryo brain spheroids

A comprehensive dataset of multielectrode array recordings was collected from three-dimensional hen embryo brain cell cultures, termed spheroids, under long-term electrical stimulation. The aim is to understand the ongoing changes in the spiking activity under electrical stimulation within the lifetime of 14-72DIV of the neuronal networks contained therein. The spiking dynamics were analyzed and behavioral characteristics derived. Some effects on spiking patterns and exhaustion were followed in culture lifetime. With respect to the culture development, two main types of spiking exhaustion were found: one which materializes in the form of a drop in the sporadic (tonic) spiking frequency at the later maturation stages; and another associated with decreasing spiking train appearance throughout an experimental period. © 2008 Uroukov and Bull

Towards unconventional computing through simulated evolution: Control of nonlinear media by a learning classifier system

We propose that the behavior of nonlinear media can be controlled automatically through evolutionary learning. By extension, forms of unconventional computing (viz., massively parallel nonlinear computers) can be realized by such an approach. In this initial study a light-sensitive subexcitable Belousov-Zhabotinsky reaction in which archeckerboard image, composed of cells of varying light intensity projected onto the surface of a thin silica gel impregnated with a catalyst and indicator, is controlled using a learning classifier system. Pulses of wave fragments are injected into the checkerboard grid, resulting in rich spatiotemporal behavior, and a learning classifier system is shown to be able to direct the fragments to an arbitrary position through dynamic control of the light intensity within each cell in both simulated and real chemical systems. Similarly, a learning classifier system is shown to be able to control the electrical stimulation of cultured neuronal networks so that they display elementary learning. Results indicate that the learned stimulation protocols identify seemingly fundamental properittes of in vitro neuronal networks. Use of another learning scheme presented in the literature confirms that such fundamental behavioral characteristics of a given network must be considered in training experiments. © 2008 Massachusetts Institute of Technology

Towards neuronal computing: simple creation of two logic functions in 3D cell cultures using multi-electrode arrays

In this paper we begin by reviewing a number of previously presented approaches to control the electrical stimulation of in vitro neuronal networks for computation through the use of multi-electrode array technology. Drawing upon this research we describe how universal computation is possible with a form of three-dimensional cell culture so long as the underlying properties of the neuronal networks therein are considered. That is, we describe how it is possible to produce the Boolean logic functions NOT and OR in vitro in a simple way

Computer music meets unconventional computing: Towards sound synthesis with in vitro neuronal networks

The feasibility of synthesizing sounds with hybrid wetware-silicon devices has been explored with the use of in vitro neuronal networks. The basics of culturing brain cells has been introduced while the procedures that has been established to stimulate the in vitro neuronal networks has been presented. Then, the technique on sonifying the behavior of neuronal networks which has been developed was described while the initial results of developing the techniques to steer the behavior of the networks have been reported. The main goal of this paper is to have some form of controllability and repeatability in the system. This sound-synthesis technique has an important property in that it has the ability to produce different types of sounds with a certain degree of predictable control

Electrophysiological measurements in three-dimensional in vivo-mimetic organotypic cell cultures: Preliminary studies with hen embryo brain spheroids

Using three-dimensional artificial tissue constructs shown to offer organotypic functionality, hen embryo brain spheroids were used as a novel electrophysiological paradigm. For the first time, single spontaneous action potentials were recorded from spheroids in culture at day 7 in vitro (DIV) using multi-electrode arrays. At DIV14 'bursting behaviour' was observed. Simple stimulation was found to induce an increase in spiking frequency with an effect that ramped up over DIV7-14. By DIV14, the frequency under stimulation was typically over twice that of the corresponding spontaneous spiking. These results indicate strong self-organizing processes in vitro within the neuronal networks of the three-dimensional spheroid cell cultures. The organotypic in vivo-mimetic nature of the spheroid paradigm was confirmed by electron microscopy that revealed an outer layer of glial cells, a glial limitans, while immunostaining for Neurofilament and Glial Fibrilliary Acidic Protein demonstrated neuronal cells with a centralized neuronal and synaptic distribution. Basic biochemical functionality was also determined and Acetylcholinesterase measured, indicating the activity of acetylcholine receptors. Thus the organotypic hen embryo brain spheroid model may offer a new paradigm in which to explore neuronal networks. © 2006 Elsevier Ireland Ltd. All rights reserved