A main challenge in the development of biosensing devices for the identification and quantification of nucleic acids is to avoid the amplification of the genetic material from the sample by polymerase chain reaction (PCR), which is at present necessary to enhance sensitivity and selectivity of assays. PCR has undoubtedly revolutionized genetic analyses, but it requires careful purification procedures that are not easily implemented in point of care (POC) devices. In recent years, a new strategy for nucleic acid detection based on clustered regularly interspaced short palindromic repeats (CRISPR) and associated protein systems (Cas) seems to offer unprecedented possibilities. The coupling of the CRISPR/Cas system with recent isothermal amplification methods is fostering the development of innovative optical and electrochemical POC devices. In this review, the mechanisms of action of several new CRISRP/Cas systems are reported together with their use in biosensing of nucleic acids.

Graphene quantum dots (GQDs) have recently been proposed as fluorescent sensors for metal ions dissolved in water. The physical origin of this fluorescence is still not completely clear, therefore further studies on GQDs and their properties are required. Graphene-like quantum dots were prepared by oxidation and unfolding of commercial buckminsterfullerene. This process was carried out by a modified Hummers method. After dialysis, the solution was diluted with deionized water to obtain the reference solution for optical measurements. Part of the solution was dried to obtain the unfolded fullerene powder. The metal ions were allowed to interact with GQDs by adding the metal-salt water solution to the stock solution of unfolded fullerene. The properties of GQDs before and after incorporation of metal ions (Hg, Cd, Pb, Cu, Ni and As) were characterized by using X-ray photoemission spectroscopy (XPS), Auger electron spectroscopy, UV-vis and fluorescent spectroscopies. In XPS, a particular attention was given to the analysis of photoemission C 1 s and Auger C KVV spectra in order to determine the carbon electronic configuration and its changes after incorporation of metal ions into GQDs. Obtained quantum dots were composed of graphene with oxidized borders. Optical measurements showed that the interaction with metal ions was changing the fluorescence intensity and optical absorbance, with different characteristics for each distinct ionic species. This behavior could be used for a selective multiple sensor detecting different heavy metals in water solutions.

Palladium thin films of different thicknesses have been processed by oxidation and subsequent reduction in hydrogen atmosphere. Hydrogen optical sensing properties of as deposited (Pd) and processed (r-Pd) samples have been experimentally tested with a H-2 concentration of 5% and 1%, discovering that the reduced films show improved performances in term of response/recovery time. As reveled by SEM images, the oxidation/ reduction process modifies the surface appearance, which assumes a nano-islands structured morphology. The porosity of the processed films may explain the reduction of the response/recovery time, while the larger effective sensing surface in thinner samples justifies the responsivity performances.

Non-destructive tools for evaluating the lycopene content in tomatoes are of great interest to the entire fruit chain because of an increasing demand for beneficial health products. With the aim of developing compact low-cost reflectance sensors for lycopene determination, we compared Partial Least Squares (PLS) prediction models by using either directional or total reflectance in the 500-750 nm range. Directional reflectance at 45 degrees with respect to the LED lighting direction was acquired by means of a compact spectrometer sensor. Total reflectance was acquired through a 50-mm integrating sphere connected to a spectrometer. The analysis was conducted on two hydroponic greenhouse cultivated red tomato varieties, namely the large round 'Dometica' (average diameter: 57 mm) and the small cherry 'Juanita' (average diameter: 26 mm). For both varieties, the spectral variance of directional reflectance was well correlated to that of total reflectance. The performances of the PLS prediction models were also similar, with R-2 of cross-validation between 0.73 and 0.81. The prediction error, relative to the mean lycopene content of full ripe tomatoes, was similar: i.e. around 16-17% for both varieties and sensors. Our results showed that directional reflectance measured by means of portable, low-cost and compact LED-based sensors can be used with an adequate precision for the non-destructive assessment of lycopene in tomatoes.

The aim of the present study is the assessment of the integration of a low cost optical measurement device into a high-precision machine tool for micro manufacturing applications. The measurement system can be effectively integrated into the working volume of different types of machines allowing both tool and workpiece measurements and avoiding its disassembly from the machine stage for off-line measurements and, consequently, reference losses. The fast measurements of tool and workpiece during the machining contribute to increase the accuracy and reduce the overall machining-measurement iterations. The assessment is achieved by a test case where a low cost USB microscope is applied to a micro-EDM machine. The low cost device has been applied for tool electrode measurements and tool wear evaluation after an accuracy enhanced calibration procedure and high performance image processing algorithms, which effectively reduce the lack of the hardware performance. The measurement performance gives a feedback on the deviations of the machined features from nominal geometry and allows their compensations by an adequate machining strategy.

The main objective of WP5000, "Future space assets for DRR (Disaster and Risk Reduction)", is to perform a gap analysis between the current space technology and the user needs required for landslide and seismic hazard mapping. As a result, a requirements baseline, including EO data types, processing methods, output products, ICTs storage and processing options, and current and future planned missions, is delivered for future space assets in DRR. WP5000 is subdivided in four sub-tasks including WP5100 "User needs analysis" aimed to define the EO technical requirements for landslide and seismic hazard evaluation, including the user required to prepare landslide inventory maps, a prerequisite for landslide hazard assessment. The deliverable describes user requirements and system specifications (satellite imagery types and characteristics) appropriate for landslide and seismic hazard evaluation. For landslide hazard we analyse: i) the requirements of the satellite images useful to prepare landslide inventory maps and ii) the system specifications for the optical and the SAR sensors. This report, will consider only the landslide inventory maps acquired using the photo-interpretation. The interpretation of aerial photographs or satellite images is the method most widely used to prepare inventory maps necessary to evaluate landslide hazard posed by a population of mass movements. For seismic hazard, we focus on the requirements associated with the existing solutions and on the ICT system specifications.

A simple, efficient and low-cost sun tracking method is presented: it is based on optical pointers used as "sun finders" and on a double guiding system. A passive tracker provides the preliminary orientation, then an active system with the sun finder realizes fine positioning and adjustments. Two optical sensors for solar pointing are proposed discussing working principle and applications. The two-axis pointer is appropriate for solar concentrators coupled to optical fibers or tiny photovoltaic cells; while the one-axis sensor is suitable for linear tracking collectors. They can be adapted to every specific application and to every solar collection device. The sensors were optically characterized indoor, under controlled and reproducible conditions, and outdoor in real working situations.

The random laser has represented an important topic in photonics and an opportunity to develop new potential practical applications. Our work, both experimental and theoretical, has been devoted to characterize, understand and control the emission in random laser systems in weakly scattering media. Three statistical regimes of the emission spectrum have been detected, besides modifications in the output directionality. Moreover, here we report our preliminary results in the field of sensing, that can open new promising perspectives.

We have fabricated, and characterized a Bragg grating, having a pitch of 10 ?m, directly etched on a porous silicon-based planar waveguide to be used as an optical sensor for chemical substances. The transmission spectrum of this device shows a well-defined peak in the near infrared wavelength region due to a high order resonance of the Bragg grating. On exposure to different volatile organic compounds the peak undergoes distinct shifts. The phenomenon is fast and completely reversible. Limits of detection of hundred of ppm can be estimated from the experimental data. © 2008 Elsevier B.V. All rights reserved.

This paper presents the development and optimization of an ultrasensitive light dosimeter, especially designed for the preventive risk assessment of damage to highly photosensitive artefacts. This indicator, named LightCheck® Ultra, is composed of a photosensitive dye/polymer layer applied on a paper support. The indicator is characterized by a progressive colour variation as the exposure to light increases. Initially blue, the colour successively changes through purple and pink to white, under the effect of visible light. The colour variation was investigated under different environmental conditions. The light-induced alterations under study were evaluated using various light sources and illuminance levels. The impact of otherfactors unconnected to light (such as temperature, humidity, indoor air pollution - atmospheric and volatile organics - and oxygen) was also studied. The behaviour of the indicator in the field in selected museums and historic houses was assessed in parallel with the laboratory experiments at each development stage. Finally, the calibration was carried out and a reference colour scale was provided for fast and easy reading of the indicator. By means of this reference colour scale, the colour exhibited by the dosimeter after an exposure can be easily correlated to a quantitative indication of the light dose received. The phases of development and testing of this novel light dosimeter are presented in detail, from the early design to the final product.

There is an increasing need for diagnostic tools that can assess the crop nitrogen (N) nutrition status during the growth cycle. In addition to the leaf chlorophyll (Chl) content, we proposed here the use of the leaf content of polyphenolics (Phen) as a potential indicator of crop N status. Because of their absorption features in the visible and in the UV part of the spectrum, both Chl and Phen can be measured by rapid and non-destructive optical methods. Therefore, we used two leaf-clip devices, the Minolta SPAD-502 for Chl, and the Dualex for Phen. The latter is a prototype (patent pending) that measures the UVabsorbance of the leaf epidermis, which is related to the leaf Phen content. Dynamics of Phen and Chl were measured on the last fully developed leaves of two winter wheat cultivars subjected to different levels of N availability, from tillering to flowering, in 2001, 2002 and 2003. Both Phen and Chl contents were found to increase along the leaf, starting from the ligula, regardless of the stage of development. Both variables were highly correlated with the N concentration of leaves. The average Chl content of the leaf increased, and the average Phen content decreased, with the increased application of N to the field, irrespective of the growth stage, the cultivar and the year of experiment. Therefore, both Phen and Chl can be considered as probes of the crop N nutrition status. Still, the relationship between Chl and the nitrogen nutrition index (NNI), used as a reference indicator of N deficiency, was influenced by the growth stage, whereas the year of experiment affected the relationship between Phen and the NNI.We also propose the use of the simple Chl/Phen ratio as an indicator of leaf N content at the canopy level, for future application in precision agriculture. This ratio would alleviate, at least partially, the problem of gradients along leaves, and would even accentuate the differences among levels of crop N deficiencies because of the Chl and Phen inverse dependence on the crop N nutrition status.