Risk assessment of biological hazards in University laboratories: checklist and critical control points.

Results: The results highlighted that 40 laboratories fall into the "low risk" and the remaining 2 into the "moderate risk" category. Conclusions: Labs with risk factors are a minority. These were properly identified using the proposed methodology. Background and aim: Biomedical research in academic settings is an important issue for Public Health and Environment protection. As workplaces, the facilities for research expose their personnel to different hazards and health risks. The University of L'Aquila (Italy) carried out a field study aimed at creating and applying a checklist intended for laboratory staff. Methods: The proposed checklist was derived from the procedure illustrated in the Appendix (procedure followed for the identification of a numerical index of biological risk for university facilities) and consists of 9 items. The study was conducted in 42 laboratories.

Active thermography for real time monitoring of UV-B plant interactions.

Although Ultraviolet-B (UV-B)-plant interactions have been extensively analysed in the past years, many physiological aspects of the complex plant response mechanisms still need to be elucidated. Depending on the energy dose, this part of the electromagnetic spectrum can induce detrimental or beneficial effects in plant and fruit. In the present work, active thermography is used to analyse in real time the response of plants under different doses of artificial UV-B. In particular, we investigated the temporal variations of the leaf surface temperature (LST) to UV-B exposure by Long Pulse and Lock-in thermography in Epipremnum aureum and in Arabidopsis plants overexpressing or knockout mutants of UVR8, the known UV-B photoreceptor. In both cases, UV-B irradiation triggers a cooling effect, namely a thermal response characterised by a LST lower respect to the initial value. Lock-in thermography demonstrated that the cooling effect is associated with an immediate mobilization and accumulation of water in the leaves. Also, we demonstrated that thermographic responses change according to the different capability of plants to tolerate high UV-B radiation. Our study highlights new physiological and physical aspects of the plants response to UV-B radiation and, more in general, it opens new opportunities for the use of the thermography as smart tool for real-time monitoring of plant environmental interactions.

A novel hybrid organic/inorganic photonic crystal slab showing a resonance action at the band edge.

Here we propose and experimentally demonstrate a hybrid photonic crystal (PC) slab consisting of air rods in a nanocomposite prepared by incorporating CdSe/CdS core/shell NRs (NR) in a polymer. Since the styrene methyl acrylate based polymer (ZEP) is transparent in the visible spectral range and is an electron-sensitive material, it was chosen as the embedding matrix for the NRs. Scanning electron microscopy and luminance measurements were 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 592 nm with a full width at half-maximum (FWHM) of 17 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.

Investigation of the optothermal properties of a new polymeric blend: polymethyl-methacrylate-poly (ethylene-co-vinylacetate).

A new polymeric blend, polymethyl methacrylate-poly (ethylene-co-vinylacetate) (PMMA-EVA) has been produced recently in our laboratories. The optothermal characterization of PMMA-EVA was carried out by measuring the ultraviolet photoacoustic spectra of PMMA, EVA, and PMMA-EVA (25 degrees C, 220-350 nm), of a PMMA-EVA blend (250-750 nm) at two temperatures (19 degrees C and 65 degrees C), and by measuring the scattering coefficient (at 514.5 nm) of PMMA-EVA versus the temperature in the range 38-86 degrees C. Our measurements show that, in the explored thermal range, the blend undergoes a phase transition when its optical properties change drastically. The peculiar optical and thermal properties observed appear attractive for possible applications as temperature-controlled optical devices.

Hysteresis transmission of evanescent waves in a composite nonlinear device.

The transition from the transmission regime to that of total internal reflection in a composite device using a nonlinear Kerr material is analyzed taking the Goos-Hänchen effect into consideration. Experimental evidence of the generation of shifted waves in such a material is shown. A computer simulation showing optical bistability in the device is also presented.