Search

Plants are subjected to a wide range of stresses which reduces the productivity of agricultural crops. In the case of cereal cultivations, climate change impacts on their production mainly through abiotic and biotic stress due for example to heat and water stress but also to pathogens such as bacteria, fungi, nematodes and others. The area under cereal cultivation is increasing worldwide, but, due to these problems, the current rates of yield growth and overall production are not enough to satisfy future demand. For this motivation, there is the needs to monitor and to control the cultivations, also developing new technological solutions useful to better optimize the management strategies, increasing both the quality of products and the quantity of the annual cereal harvest. Infrared imaging is a well-known non-invasive and non-contact technique that represents an outstanding approach of analysis applied in many fields: engineering, medicine, veterinary, cultural heritage and others. In recent years it has been gaining great interest in agriculture as it is well suited to the emerging needs of the precision agriculture management strategies. In this work, we performed an in-field multispectral infrared monitoring of different cereal crops (durum wheat and common wheat) through the use of both LWIR and MWIR cameras. The monitoring carried out made it possible to identify, among the crops analyzed, those subject to higher stress levels and their response to the different spectral ranges used. The results obtained open to the possibility of identifying new figures of merit useful for an effective monitoring of cereal crops and measurable through remote instrumentation.

A 2-D approach, based on Infrared (IR) imaging for monitoring and optimizing the photo-therapy in dermatology, is proposed. We studied the possibility to employ IR imaging in order to select the laser treatment parameters for each patient. A Pulsed Thermography (PT) model allowed to evaluate morphological information on the specific area to treat after a single laser pulse test. The data were elaborated through a 2-D numerical simulation, which described the tissue temperature profiles for different sets of laser parameters. Based on this approach, it was possible to select the laser parameters according to specific pathology, morphology and phototype in order to achieve the best performances in the phototherapy practice.

Abstract: 6-Phosphogluconate dehydrogenase catalyzes the oxidative decarboxylation of 6-phosphogluconate to ribulose 5-phosphate through an oxidation, a decarboxylation and a tautomerization. The two subunits in the crystals of the dimeric sheep liver enzyme have the same conformation, as the apoenzyme and with the substrate or coenzyme. An hypothesis is now advanced that in solution, during catalysis, the two subunits have a different alternating role and thus a functional asymmetry.

Two different metamaterial-liquid crystal structures are fabricated with the metamaterials as LC and semiconductor nanorods doped LC alignment layers. E-beam lithography was used to pattern the electron-sensitive polymer 1D PC structures. The nanostructured aligning surfaces have been characterized by Scanning Electron Microscopy. The Photonic Crystals-Dispersed Liquid Crystalline Metamaterials (PCs-DLCMs) have been investigated through polarized optical microscopy. The threshold voltage and response times for the undoped and doped nematic LCs in the glass cells are measured as a function of the applied external electric field.

A 2D hybrid Photonic Crystal (PC) which consists of air rods in a nanocomposite prepared by incorporating CdSe/CdS core/shell nanorods (NR) in a polymer is proposed and experimentally demonstrated. Since the styrene methyl acrilate based polymer (ZEP) is transparent in the visible spectral range and it is an electron-sensitive material, it was chosen as the embedding matrix for NRs. Scanning electron microscopy and luminance measurements are used to characterize the experimental structure. The vertical extraction of the light, by the coupling of the modes guided by the PC slab to the free radiation via Bragg scattering, consists of a narrow orange emission band at 596 nm with a full width at half-maximum (FWHM) of 10 nm. The original characteristics of hybrid materials based on polymers and colloidal NRs, able to combine the unique optical properties of the inorganic moiety with the processability of the host matrix, are extremely appealing in view of their technological impact on the development of new high performing optical devices such as organic light-emitting diodes, ultra-low threshold lasers and non-linear devices.

Low-loss polymer waveguides fabricated from chlorinated copolymers by photochemical crosslinking were prepared and characterized. A novel monomer derived from reaction between glycidyl methacrylate (GMA) and Disperse Red 19 (DR19) chromophore was prepared and successfully copolymerized with chlorostyrene (CS) to obtain the dye-modified copolymer. The latter was crosslinked by photoinitiated polymerization of the pendant epoxy groups, to obtain stable polymer waveguides. It was found that the predominant product of the reaction between GMA and DR19 was formed through transesterification of the methacrylate with elimination of glycidol, while traces of products deriving from the epoxy ring-opening reaction were detected. The presence of the nitro substituent on DR19 favoured chain transfer reactions during the polymerization reaction, leading to a decrease in the polymerization degree. It was also observed that the presence of grafted DR19 negatively affected the crosslinking reaction, as a lower epoxy group conversion was observed for the modified copolymer. Thermal analysis indicated that the copolymer containing DR19 showed increased thermal stability. m-line spectroscopy was used to measure the refractive index at 632.8 nm. The experimental results confirm that the new class of chlorine-based polymeric materials represent a very attractive proposal in the panorama of materials employed in the fabrication of electro-optical devices for telecommunication applications.

The authors report a new thermal annealing technique for Nb/Al-AlOx/Nb Josephson devices based on laser heating. This technique allows to "locally" modify the Josephson critical current density. In fact, it is possible the heating of a single circuit element with a good spatial resolution using a focused Ar+ laser beam which is aligned by an optical system on a selected junction of the sample. During the procedure, performed at room temperature, a thermal camera provides a monitoring of the temperature distribution on the whole chip. A continuous reduction of the critical current density up to about 40% has been observed on high quality Josephson junction measured in liquid helium. Neighbouring junctions have not exhibited any measurable change ensuring the effective capability to locally modify the Josephson critical current density. The new technique has been employed to recover noisy dc SQUID magnetometers with non optimal critical current values obtaining a reduction of the spectrum density of magnetic field noise from about 30 to 2.5 fT/Hz ½ .