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This review examines the applications of electronic noses and tongues in food analysis. A brief history of the development of sensors is included and this is illustrated by descriptions of the different types of sensors utilized in these devices. As pattern recognition techniques are widely used to analyse the data obtained from these multisensor arrays, a discussion of principal components analysis and artificial neural networks is essential. An introduction to the integration of electronic tongues and noses is also incorporated and the strengths and weaknesses of both are described. Applications described include identification and classification of flavour and aroma and other measurements of quality using the electronic nose. The uses of the electronic tongue in model analyses and other food, beverage and water monitoring applications are discussed.

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Motion contained within a static object can cause illusory position shifts toward the direction of internal motion. Here we present data suggesting this illusion is driven by modulations of apparent contrast. We observe position shifts at blurred stimulus regions without corresponding changes to internal structure, and find that low-contrast targets are more difficult to detect at the trailing, as opposed to leading, edges of movement. Motion induced position shifts are also shown to occur without conscious appreciation of motion direction. Our data suggests that motion can influence spatial coding via interactions that modulate apparent contrast, thereby changing the regions of the stimulus that are visible.

Risks of low birthweight and preterm birth were highest for women prescribed or recommended NRT. These findings may be related to frequency of maternal smoking. While heavier smokers may be more likely to be recommended NRT, they also may have the most difficulty with cessation. Greater efforts should be made to ensure that these women do successfully cease smoking.

Results of X-ray photoelectron spectroscopic studies on the surface of silicon wafers sllanlzed with dlchlorodlmethylsllane, methyltrichlorosilane, ((glycklyloxy)propyl)trlmethoxysllane, (amlnopropyl)trlethoxysllane, tort -butyldlmethylchlorosllane, and the 12-dlchloromonomethylsllyl and 12-monochlorodlmethylsllyl ethers of methyl 12-hydroxydodecanoate are reported. The upward shift In the SI (2p) binding energies (by 0.5 eV) of surface silicons treated with silylatlng agents In the presence of Et3N was attributed to hydroxyl functionalities on these atoms. The extent of surface coverage was computed from the surface Sksubstrate SI ratios. Large differences In reactivities of the silylating agents were observed in the presence or absence of the base catalyst.

This work describes the application of acoustic wave technology for the real-time and label-free detection of biotin-avidin interactions. Biosensing surfaces are constructed onto unelectroded piezoelectric quartz discs as functionalizable mixed self-assembled monolayers (SAM) produced from previously unreported linker and diluent molecules. Biotinthiol can subsequently be immobilized for detection purposes in a straightforward and coupling-free manner. Specific and non-specific adsorptions of avidin are measured at ultra-high frequencies (1.06 and 0.82 GHz) with an electromagnetic piezoelectric acoustic sensor (EMPAS) using micromolar avidin-spiked buffer solutions. These biosensing surfaces, especially the oligoethylene glycol SAM-based variety, display high specificity for avidin, with moderate to excellent reproducibility. This preliminary work constitutes the first application of SAM chemistry and EMPAS technology in the bioanalytical field.

A thickness shear-mode acoustic wave device, operated in a flow-through format, was used to detect the binding of ions or peptides to surface-attached calmodulin. On-line surface attachment of the protein was achieved by immobilisation of the biotinylated molecule via a neutravidin-biotin linkage onto the surface of the gold electrode of the detector. The interaction between calmodulin, and calcium and magnesium ions induced an increase in resonant frequency and a decrease in motional resistance, which were reversible on washing with buffer. Interestingly, the changes in resonant frequency and motional resistance induced by the binding were opposite to the normal operation of the detector. The response was interpreted as a decrease in surface coupling (partial slip at the liquid/solid interface) instigated by exposure of hydrophobic domains on the protein, and an increase in the thickness, and hence effective wavelength, of the acoustic device, corresponding to an increase in the length of calmodulin by 1.5 A. This result is consistent with the literature value of 4 A. In addition, the interaction of the protein with peptide together with calcium ions was detected successfully, despite the relatively low molecular mass of the 2-kDa peptide. These results confirm the potential of acoustic wave physics for the detection of changes in the conformational chemistry of monolayer of biochemical macromolecules at the solid/liquid interface.