Fibre tip sensor with embedded FBG-LPG for temperature and refractive index determination by means of the simple measurement of the FBG characteristics

A novel optical fibre sensing system based on a hybrid long period grating (LPG) and Bragg grating (FBG) configuration is proposed and demonstrated experimentally. The hybrid configuration, which uses the difference in temperature and refractive index (RI) different response of a Bragg grating and a long period grating, makes it possible to discriminate simultaneously the temperature and the refractive index of different aqueous solutions. RI (1.33 RIU-1.40 RIU) and temperature (21°C-28°C) working ranges have been experimentally determined. Experimental results show that the maximum accuracy in the refractive index measurement (0.004 RIU) with temperature compensation has been achieved within the working ranges

Alimenti e nutraceutici: qualità e salute del consumatore

Junipers ar

Development and validation of analytical method to monitor the BVOC emission in Sibillini National Park using TD-GC-MS

Biogenic volatile organic compounds (BVOCs), are a heterogeneous group of molecules with a wide range of functions useful for plants and, consequently, for the whole ecosystem and the environment[1]. A rapidly and inexpensive analytical method is presented that is based on the use of thermal gas-chromatography (TD-GC-MS) to monitor BVOCs released by Juniperus Communis in Sibillini National Park. Hexanal, Toluene, α-Pinene, 4-Terpineol and β-Caryophyllene have been used as standard compounds. This method showed a good sensibility (limit of detection ranges between 10-19 pptv for all compounds except for Hexanal that is 100 pptv), repeatability (RDS% within 11%), precision (recovery higher than 85%) and selectivity. We collected samples in situ from April 2016 to September 2017 almost once for months. The compounds have been identified using Kovats retention indices (RI) and quantified with the response factor (RF) for different class of compounds. All samples have been correlated with temperature and humidity values. The results show higher emission in April (flowering period) and at particular condition of temperature (24°C). These results are comparable to the data found in the literature about emissions of Juniperus Communis, confirming the validity of the developed method[2][3]

Effectiveness of selected essential oils and one hydrolate to prevent and remove Listeria monocytogenes biofilms on polystyrene and stainless steel food-contact surfaces

Aims: This study aimed to evaluate the effectiveness of selected essential oils (EOs) and hydrolates (Hs) against Listeria monocytogenes biofilms on polystyrene (PS) and stainless steel (SS) surfaces. Methods and results: Among others, Origanum hirtum EO, Corydothymus capitatus EO and Citrus aurantium H were selected to treat L. monocytogenes biofilms during and after biofilm formation. Sub-minimum inhibitory concentrations (MICs) of C. capitatus EO (0.31 µl/ml) showed the highest inhibiting effect against biofilm formation on PS, while on SS no significant differences between the EOs were observed (43.7%-88.7% inhibition). Overall, the tested biosanitizers showed limited activity as biofilm removal agents. Although generally less effective, C. aurantium H exhibited good biofilm inhibition performance at 62.5 µl/ml, particularly on PS. Confocal laser scanning microscopy proved that sub-MICs of the biosanitizers drastically changed L. monocytogenes biofilm architecture, with bacterial cells elongation in the presence of C. capitatus EO. Conclusions: Our findings suggest that the tested EOs and H are able to control Listeria biofilms, particularly preventing biofilm formation on both materials. Considering its mild aroma and hydrophilicity, the H exhibited promising perspectives of application. Significance and impact of study: This study raises the possibility of applying EOs and Hs to control biofilms on different surfaces in the food industry

The pioneering work of Enrico Morselli (1852–1929) in light of modern scientific research on hypnosis and suggestion

This article examines research on hypnosis and suggestion, starting with the nineteenth-century model proposed by Enrico Morselli (1852–1929), an illustrious Italian psychiatrist and psychologist. The authors conducted an original psychophysiological analysis of hypnosis, distancing the work from the neuropathological concept of the time and proposing a model based on a naturalistic approach to investigating mental processes. The issues investigated by Morselli, including the definition of hypnosis and analysis of specific mental processes such as attention and memory, are reviewed in light of modern research. From the view of modern neuroscientific concepts, some problems that originated in the nineteenth century still appear to be present and pose still-open questions