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Online sensitive monitoring of gene expression is essential for understanding microbial life and microbial communities, especially under stress-inducing conditions, such as the presence of environmental pollutants. We describe here a novel use of promoter-based electrochemical biosensing for online and in situ monitoring of gene expression in response to pollutants. As a model system, we used a cadmium-responsive promoter from Escherichia coil fused to a promoterless lacZ gene, which was monitored using an electrochemical assay of beta-galactosidase activity. This whole-cell biosensor could detect, within minutes, nanomolar concentrations of cadmium in water, sea water and soil samples, and it can be used for continuous online and in situ monitoring.

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It is well known that many students encounter difficulties when solving problems in mathematics. Research indicates that some of these difficulties may stem from intuitive interference with formal/logical reasoning. Our research aims at deepening the understanding of these difficulties and their underlying reasoning mechanisms to help students overcome them. For this purpose we carried out behavioral, brain imaging and intervention studies focusing on a previously demonstrated obstacle in mathematics education. The literature reports that many students believe that shapes with a larger area must have a larger perimeter. We measured the accuracy of responses, reaction time, and neural correlates (by fMRI) while participants compared the perimeters of geometrical shapes in two conditions: (1) congruent, in which correct response was in line with intuitive reasoning (larger area-larger perimeter) and (2) incongruent, in which the correct answer was counterintuitive. In the incongruent condition, accuracy dropped and reaction time for correct responses was longer than in the congruent condition. The congruent condition activated bilateral parietal brain areas, known to be involved in the comparison of quantities, while correctly answering the incongruent condition activated bilateral prefrontal areas known for their executive control over other brain regions. The intervention, during which students' attention was drawn to the relevant variable, increased accuracy in the incongruent condition, while reaction times increased in both congruent and incongruent conditions. The findings of the three studies point to the importance of control mechanisms in overcoming intuitive interference in mathematics. Overall, it appears that adding a cognitive neuroscience perspective to mathematics education research can contribute to a better understanding of students' difficulties and reasoning processes. Such information is important for educational research and practice.

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