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Dryocosmus kuriphilus is the most impactful alien pest of chestnut currently reported in almost the whole Europe after its accidental introduction in Piemonte (North-west Italy) where it was found for the first time in 2002. The Piemonte Region Administration funded a project aimed to find control solutions based on both the biological control of gall-wasp and the study of plant response. This work was carried out from 2004 to 2013 and reports studies on assessment of production loss (2006–2012), cultivar susceptibility (2004–2013) and amount of nutrients subtraction caused by the insect (2012). The assessment of yield loss showed that infestation values (G/B = No. galls/bud) lower than 0.3 G/B caused no significant losses; values between 0.3–0.6 G/B originated a moderate decrease in productivity. A drastic decrease of productivity was observed for values above 0.6 G/B. A second objective was to assess varietal susceptibility in 62 cultivars. The susceptibility trait showed a wide range of variation from total resistance (7 cultivars: two Castanea sativa , one Castanea crenata and 4 Euro-Japanese hybrids) to high susceptibility (>0.6 G/B; 14 cultivars). Finally, size and proximate differences in leaves with gall and healthy leaves were studied to assess the changes due to infestation. Significant differences for leaf area, moisture, dry matter, ash, sugars, starch, and total carbohydrates were observed between the two types of leaves indicating a deep influence of the infestation on leaf functionality and on its photosynthetic capacity.

The issue of detecting harmful compounds in water may be approached in different ways, ranging from analytical methods to chemical sensor arrays. Optochemical sensors offer the advantage of being a simple and effective method for online monitoring of the parameters of interest in water solution. The core of an optochemical sensor is represented by a dye that changes colour upon the interaction with analytes. In this work, we used porphyrins, pH indicators and their mixtures to prepare the colorimetric sensor array for the analysis of ionic salts and organic compounds in water. The colour changes of sensing dyes exposed to an aqueous solution containing target compounds were read out with a system consisting of a computer screen (light source) and a digital camera (detector). Beyond the detection of metallic salts, nitrites, nitrates, phosphates, and organic compounds, we found that the array can recognize creatinine and urea, two markers of kidney functionalities.

Sensor networks prompt a great deal of research interest within the computer and analytical sciences. To this regard, one of the most important issues is concerned with the interpretation of data that are collected by different sensors. Due to sensors non-reproducibility, this problem may also persist even when many replicas of the same sensors are considered. In this case additional calibrations may be required to use a common knowledge database. Noteworthy, the same problem arises in case of sensors replacement. In this paper we demonstrate that in case of optical chemical sensors drawing inspiration from the connectivity strategy of the olfactory bulb, this problem can find a straightforward solution when an image sensor is used to measure the optical properties of an extended sensing layer. If the sensing layer is formed by a number of spots of different indicators, it is demonstrated that a common data processing can be applied to any replica of the sensing layer even if the indicators are spotted with different geometries and in different quantities.

Polymers are commonly used in optical chemical sensors as inert supports for indicator dyes keeping the molecules apart to allow for exposure to analytes and to maintain the peculiar optical properties of the sensitive dyes. However, the partitioning properties of polymers may play a significant role in determining the sensitivity of the sensors. Herewith, the properties of a single dye blended with different polymers have been studied through optical absorbance changes elicited by the exposure to organic vapors. Results show that the partitioning properties of polymers modulate the response of the dye and confer a combinatorial selectivity to the system, allowing for the recognition of vapors.

Sensors are the less durable parts in any chemical sensor system, then the replacement of sensors maintaining hardware and data processing is a necessity in real applications. Though sensors replacement requires a perfect reproducibility of the sensors fabrication. Among the different sensor technologies, those based on optical transduction may offer a straightforward methodology to release the requirement of identical sensor manufacturing. In particular it will be shown here that the use of image sensor provides a surprising parallel with natural olfaction. An important consequence is that the data processing is independent from the geometric arrangement of the sensitive layer. This feature leads to a simple sensor layer replacement and to a prompt arrangement of different sensor systems, even remotely located, into a single data processing system.

In chemical sensors, polymers are frequently used as inert matrices to support chemical indicators, keeping the molecules apart to allow for exposure to analytes. However, the partitioning properties of polymers can play a significant role in determining the properties of chemical sensors. Herewith, the properties of two dyes blended with different polymers have been studied through optical absorbance changes elicited by the exposure to organic vapors. Results show that the partitioning properties of polymers modulate the response of the dyes and confer a broader selectivity to the system, allowing for qualitative analysis of the tested vapors.

Summary Optical sensors based on image acquisition hardware represent a promising technique to measure the chemical composition of an environment or the headspace generated by complex samples. However, this approach is still limited by the fact that only a restricted kind of interactions may change the visible spectrum of an indicator. As a consequence, the receptive field, namely the amount of different chemicals that can be captured by an opto-chemical sensor, is rather restricted. To extend the application of optical indicators we propose to use blends of porphyrins and acid-base indicators as materials for opto-chemical sensors. A suitable choice of the components allows to obtain sensing features that are not correlated to those of the single constituents. This strategy provides a straightforward method to develop sensor arrays for a wide number of practical applications, among them it is investigated here the measure of emissions from human skin.