Fourier Transform Infrared Spectroscopy has been employed to investigate the composition of the shells of two marine bivalves Mytilus galloprovincialis and Corbula gibba from four samples collected ...from the Mar Piccolo of Taranto (Ionian Sea, Southern Italy). Bivalve shells are composed of 95–99.9% calcium carbonate (CaCO3), while the remaining portion is constituted by organic matrix, which in some cases may incorporate pollutants from the surrounding environment. Recognizing the role of bivalves in the carbon biogeochemical cycle and their economic importance for aquaculture, we aimed to develop a methodology for shells powder samples preparation and analysis. The main objective of the study was to demonstrate the feasibility of Fourier Transform Infrared photoacoustic spectroscopy to perform a fast sample analysis in order to detect the possible presence of pollutants in the shells.
The results revealed an unbiased differentiation between the shell compositions of the two bivalve selected species. Moreover, the spectra interpretation indicated that C. gibba specimens recorded a shell matrix contaminated by organic pollutants present in the surrounding environment. In conclusion, the described methodology including sample preparation tailored for photoacoustical investigations demonstrated to be a tool for the characterization of bivalve shells contamination enhancing environmental studies of polluted marine areas.•Bivalve species were collected from sampling stations located in the Mar Piccolo of Taranto (Ionian Sea, Southern Italy).•Samples preparation stages include: sonication, grinding and fractioning by sieving.•FT-IR PAS spectral region of interest is in the mid-infrared between 4000 and 400 cm−1.
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Titanium dioxide (TiO2) is at the basis of many important applications which are decisively controlled by its photophysical characteristics. Photoluminescence (PL) analysis provides important ...information on these latter, while also representing a less explored and possibly multi-parametric route to chemical sensing. In the present work we show that oxygen exposure produces opposite responses in the PL activity of the two most common TiO2 polymorphs (rutile and anatase) and discuss the origin of such a phenomenon, focusing in particular on the near-infrared PL characteristic for rutile TiO2. We propose an interpretation of the experimental findings in terms of two possible O2/TiO2 interaction routes, namely: (a) molecular chemisorption of oxygen and consequent dynamics of self-trapped hole states close to the sample surface and (b) dissociative chemisorption of oxygen, affecting the density of oxygen vacancies at (or close to) the surface. The remarkable result of an individual analyte producing different detectable effects on a same sensing material epitomizes the potentialities offered by an optical PL-based approaches toward multi-parametric chemical sensing, encouraging the exploration beyond the established chemoresistive approaches which are based on a single parameter. Moreover, it highlights interesting prospects for TiO2-based optical sensing.
We report a correlative imaging analysis of a crystalline silicon target after irradiation with a low number of 1055 nm, ~ 850 fs laser pulses with several microscopy techniques (e.g., scanning ...electron microscopy, atomic force microscopy, Raman micro-imaging and confocal optical microscopy). The analysis is carried out on samples irradiated both in high vacuum and at atmospheric pressure conditions, evidencing interesting differences induced by the ambient environment. In high-vacuum conditions, the results evidence the formation of a halo, which is constituted by alternate stripes of amorphous and crystalline silicon, around the nascent ablation crater. In air, such an effect is drastically reduced, due to the significant back-deposition of nanoparticulate material induced by the larger ambient pressure.
We report an experimental investigation on the surface structures induced by linearly polarized ≈ 900 fs laser pulses, at
λ
= 1055 nm, on silicon at different values of the ambient pressure, from ~ ...10
−4
mbar to one atmosphere. Our experimental findings address interesting influences of the surrounding pressure on: (1) the spatial period of ripples; (2) the formation of micro-grooves; (3) the shape of the structured area. Moreover, the effects of various states of polarization in vacuum as well as of circularly polarized pulses in air vs vacuum are also addressed. We identify as one possible key element of such experimental observations: the fact that as the pressure raises the ablated nanoparticles produced during the femtosecond ablation process of the target get deposited more and more on the sample surface covering the irradiated spot area and influencing the structuring process.
The outbreak of coronavirus disease-2019 (COVID-19) is a public health crisis of global proportion. In psoriatic patients treated with biologic agents, evidence is not yet available on susceptibility ...to infection with the novel SARS-CoV-2 coronavirus, and data about the perception of COVID-19 and its impact on these patients are lacking.
The aim of this observational, spontaneous study was the evaluation of the impact of anti COVID-19 measures in “fragile population” such as patients with a chronic inflammatory disease. Thus, we evaluated the impact of perceived risk on quality of life of patients with moderate to severe psoriasis, in our outpatient clinic, and how their perceptions changed before and after the adoption of Covid-19 emergency measures following the Italian Ministerial Decree in March 9, 2020.
Using a series of questions, our study surveyed adult patients with moderate to severe psoriasis receiving treatment with biologic agents (n = 591), before and after the adoption of COVID-19 emergency measures.
Most patients (97%) had been sufficiently informed by healthcare staff about COVID-19 spread. A significant change was observed in social activity reduction before and after the adoption of the measures (18% vs. 90% of patients; P < 0.0001). Similarly, patients were more likely to suspend ongoing therapy after the measures were adopted than before (87% vs. 34% of patients; P < 0.0001). Following the measures, older patients were significantly more inclined to suspend therapy and reduce social activities than younger patients.
Government COVID-19 emergency measures further curtailed already reduced social activities in psoriatic patients, and led to a greater inclination to suspend biologic therapy, more so in older patients, despite there being no evidence to support this suspension. These vulnerable patients may need support from clinicians in order to maintain treatment adherence.
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