Structural Analysis of Si(OEt)4 Deposits on Au(111)/SiO2 Substrates at the Nanometer Scale Using Focused Electron Beam-Induced Deposition.

The focused electron beam-induced deposition (FEBID) process was used by employing a GeminiSEM with a beam characteristic of 1 keV and 24 pA to deposit pillars and line-shaped nanostructures with heights between 9 nm and 1 µm and widths from 5 nm to 0.5 µm. All structures have been analyzed to their composition looking at a desired Si/O/C content measuring a 1:2:0 ratio. The C content of the structure was found to be ∼over 60% for older deposits kept in air (∼at room temperature) and less than 50% for later deposits, only 12 h old. Upon depositing Si(OEt)4 at high rates and at a deposition temperature of under 0 °C, the obtained Si content of our structures was between 10 and 15 atom % (compositional percentage). The FEBID structures have been deposited on Au(111)/SiO2. The Au(111) was chosen as a substrate for the deposition of Si(OEt)4 due to its structural and morphological properties. With its surface granulation following a Chevron pattern and surface defects having an increased contribution to the changes in the composition of the final structure content, the Au(111) surface characteristic behavior at the deposition of Si(OEt)4 is an increase in the O ratio and a reduction in the nanodeposit heights.

Source apportionment of PM2.5 before and after COVID-19 lockdown in an urban-industrial area of the Lisbon metropolitan area, Portugal.

The lockdowns held due to the COVID-19 pandemic conducted to changes in air quality. This study aimed to understand the variability of PM2.5 levels and composition in an urban-industrial area of the Lisbon Metropolitan Area and to identify the contribution of the different sources. The composition of PM2.5 was assessed for 24 elements (by PIXE), secondary inorganic ions and black carbon. The PM2.5 mean concentration for the period (December 2019 to November 2020) was 13 ± 11 µg.m-3. The most abundant species in PM2.5 were BC (19.9%), SO4 2- (15.4%), NO3 - (11.6%) and NH4 + (5.3%). The impact of the restrictions imposed by the COVID-19 pandemic on the PM levels was found by comparison with the previous six years. The concentrations of all the PM2.5 components, except Al, Ba, Ca, Si and SO4 2-, were significantly higher in the winter/pre-confinement than in post-confinement period. A total of seven sources were identified by Positive Matrix Factorisation (PMF): soil, secondary sulphate, fuel-oil combustion, sea, vehicle non-exhaust, vehicle exhaust, and industry. Sources were greatly influenced by the restrictions imposed by the COVID-19 pandemic, with vehicle exhaust showing the sharpest decrease. Secondary sulphate predominated in summer/post-confinement. PM2.5 levels and composition also varied with the types of air mass trajectories.

Spatial Distribution of Air Pollution, Hotspots and Sources in an Urban-Industrial Area in the Lisbon Metropolitan Area, Portugal-A Biomonitoring Approach.

This study aimed to understand the influence of industries (including steelworks, lime factories, and industry of metal waste management and treatment) on the air quality of the urban-industrial area of Seixal (Portugal), where the local population has often expressed concerns regarding the air quality. The adopted strategy was based on biomonitoring of air pollution using transplanted lichens distributed over a grid to cover the study area. Moreover, the study was conducted during the first period of national lockdown due to COVID-19, whereas local industries kept their normal working schedule. Using a set of different statistical analysis approaches (such as enrichment and contamination factors, Spearman correlations, and evaluation of spatial patterns) to the chemical content of the exposed transplanted lichens, it was possible to assess hotspots of air pollution and to identify five sources affecting the local air quality: (i) a soil source of natural origin (based on Al, Si, and Ti), (ii) a soil source of natural and anthropogenic origins (based on Fe and Mg), (iii) a source from the local industrial activity, namely steelworks (based on Co, Cr, Mn, Pb, and Zn); (iv) a source from the road traffic (based on Cr, Cu, and Zn), and (v) a source of biomass burning (based on Br and K). The impact of the industries located in the study area on the local air quality was identified (namely, the steelworks), confirming the concerns of the local population. This valuable information is essential to improve future planning and optimize the assessment of particulate matter levels by reference methods, which will allow a quantitative analysis of the issue, based on national and European legislation, and to define the quantitative contribution of pollution sources and to design target mitigation measures to improve local air quality.

Proton beam irradiation induces invisible modifications under the surface of painted parchment.

Ion beam analysis plays an important role in cultural heritage (CH) studies as it offers a combination of simultaneous and complementary analytical techniques (PIXE/PIGE/RBS) and spatially resolved mapping functions. Despite being considered non-destructive, the potential risk of beam-induced modifications during analysis is increasingly discussed. This work focuses on the impact of proton beams on parchment, present in our CH in form of unique historical manuscripts. Parchment is one of the organic, protein-based CH materials believed to be the most susceptible to radiation-induced changes. Various modification patterns, observed on parchment cross-sections by optical and electron microscopy are reported: discoloration (yellowing), formation of cavities and denaturation of collagen fibers. Considerable modifications were detected up to 100 µm deep into the sample for beam fluences of 4 µC/cm2 and higher. The presence of ultramarine paint on the parchment surface appears to increase the harmful effects of proton radiation. Based on our results, a maximum radiation dose of 0.5 µC/cm2 can be considered as 'safe boundary' for 2.3 MeV PIXE analysis of parchment under the applied conditions.

Inter-laboratory comparison of ED-XRF/PIXE analytical techniques in the elemental analysis of filter-deposited multi-elemental certified reference materials representative of ambient particulate matter.

The quantification of the elemental concentration of ambient particulate matter is a challenging task because the observed elemental loadings are not well above the detection limit for most analytical techniques. Although non-destructive nuclear techniques are widely used for the chemical characterization of ambient aerosol, only one multi-element standard reference filter material that mimics ambient aerosol composition has become recently available in the market. To ensure accuracy, reliability and comparability of instruments performance, multiple reference materials with different elemental mass loadings are necessary. In this study, an intercomparison exercise was performed to evaluate the measurement uncertainty and instruments performance using multi-element dust standard reference samples deposited on PTFE filters. The filter samples, produced by means of dust dispersion, were tested in terms of homogeneity, reproducibility and long-term stability (≈40 months). Eight laboratories participated in the exercise. The evaluation of the results reported by the participants was performed by using two sets of reference values: a) the concentrations reported by the Expert Laboratory, b) the robust average concentrations reported by all participants. Most of the reported on the certificate of analysis elements were efficiently detected in the sample loadings prepared as representative for atmospheric samples by the Expert Laboratory. The average absolute relative difference between the reported and the reference values ranged between 0.1% (Ti) and 33.7% (Cr) (CRM-2584). The participants efficiently detected most of the elements except from the elements with atomic number lower than 16 (i.e. P, Al, Mg). The average absolute percentage difference between the participants results and the assigned value as derived by the expert laboratory was 17.5 ± 18.1% (CRM-2583; Cr, Pb excluded) and 16.7 ± 16.7% (CRM-2584; Cr, P excluded). The average "relative robust standard deviation" of the results reported by all participants was 25.1% (CRM-2583) and 22.8% (CRM-2584).

Increased Cd2+ biosorption capability of Aspergillus nidulans elicited by crpA deletion.

The P-type ATPase CrpA is an important Cu2+ /Cd2+ pump in the Aspergilli, significantly contributing to the heavy metal stress tolerance of these ascomycetous fungi. As expected, the deletion of crpA resulted in Cu2+ /Cd2+ -sensitive phenotypes in Aspergillus nidulans on stress agar plates inoculated with conidia. Nevertheless, paradoxical growth stimulations were observed with the ΔcrpA strain in both standard Cu2+ stress agar plate experiments and cellophane colony harvest (CCH) cultures, when exposed to Cd2+ . These observations reflect efficient compensatory mechanisms for the loss of CrpA operating under these experimental conditions. It is remarkable that the ΔcrpA strain showed a 2.7 times higher Cd biosorption capacity in CCH cultures, which may facilitate the development of new, fungal biomass-based bioremediation technologies to extract harmful Cd2+ ions from the environment. The nullification of crpA also significantly changed the spatial distribution of Cu and Cd in CCH cultures, as demonstrated by the combined particle-induced X-ray emission and scanning transmission ion microscopy technique. Most important, the centers of gravity for Cu and Cd accumulations of the ΔcrpA colonies shifted toward the older regions as compared with wild-type surface cultures.

A Dietary Intervention of Bioactive Enriched Foods Aimed at Adults at Risk of Metabolic Syndrome: Protocol and Results from PATHWAY-27 Pilot Study.

Around a quarter of the global adult population have metabolic syndrome (MetS) and therefore increased risk of cardiovascular mortality and diabetes. Docosahexaenoic acid, oat beta-glucan and grape anthocyanins have been shown to be effective in reducing MetS risk factors when administered as isolated compounds, but their effect when administered as bioactive-enriched foods has not been evaluated. OBJECTIVE: The overall aim of the PATHWAY-27 project was to evaluate the effectiveness of bioactive-enriched food consumption on improving risk factors of MetS. A pilot study was conducted to assess which of five bioactive combinations provided within three different food matrices (bakery, dairy or egg) were the most effective in adult volunteers. The trial also evaluated the feasibility of production, consumer acceptability and gastrointestinal tolerance of the bioactive-enriched food. METHOD: The study included three monocentric, parallel-arm, double-blind, randomised, dietary intervention trials without a placebo. Each recruiting centre tested the five bioactive combinations within a single food matrix. RESULTS: The study was completed by 167 participants (74 male, 93 female). The results indicated that specific bioactive/matrix combinations have effects on serum triglyceride or HDL-cholesterol level without adverse effects. CONCLUSION: The study evidenced that bioactive-enriched food offers a promising food-based strategy for MetS prevention, and highlighted the importance of conducting pilot studies.

Stability and bioaccessibility of anthocyanins in bakery products enriched with anthocyanins.

Anthocyanins, water soluble polyphenols, have been associated with several beneficial health effects. The aim of this study was to determine how the baking process and food matrix affect anthocyanin stability and bioaccessibility in bakery products in order to develop functional foods. Three well known regularly consumed bakery products (buns, breadsticks and biscuits) were enriched with anthocyanin (AC) isolated from grape skin alone or in combination with docosahexaenoic acid (AC + DHA) to reveal knowledge on AC as active ingredients in real food systems rather than pure compounds. Anthocyanin amounts added to the formulations of buns, breadsticks and biscuits were 34 mg per 100 g, 40 mg per 100 g and 37 mg per 100 g, respectively. The effect of processing, storage and the food matrix on AC stability and bioaccessibility was investigated. In addition, the sensory properties of bakery products were evaluated. Breadsticks enriched with AC and AC + DHA received the lowest scores in the pre-screening sensory test. Therefore breadsticks were excluded from further analysis. AC retentions, which were monitored by determination of malvidin 3-O-glucoside, in the bun and biscuit after baking were 95.9% (13.6 mg per 100 g) and 98.6% (15.2 mg per 100 g), respectively. Biscuits and buns enriched only with AC showed significantly higher anthocyanin bioaccessibilities (57.26% and 57.30%, respectively) than the same ones enriched with AC + DHA. AC stability in enriched products stored for 21 days was significantly lower than in products stored for 7 days (p < 0.05). However, this loss can be accepted as negligible since more than 70% of AC was retained in all the products.

Investigation of micronized titanium dioxide penetration in human skin xenografts and its effect on cellular functions of human skin-derived cells.

Titanium dioxide (TiO2) nanoparticles are ubiquitously used materials in everyday life (e.g. paints,household products and plastic goods). However, despite the wide array of common applications, their pathogenetic role was also suggested under certain conditions (e.g. pulmonary neoplasias and lung fibrosis). From a dermatological point of view, it is also of great importance that TiO2 also serves as a physical photoprotective agent in sunscreens and is widely used in various cosmetic products. However, the effect of TiO2 on human cutaneous functions is still unknown. Therefore, in the current study, we investigated the in vivo penetration of TiO2 via human skin transplanted to immunodeficient mice and,furthermore, we measured the in vitro effects of nanoparticles on various functional properties of numerous epidermal and dermal cells in culture. Hereby, using various nuclear microscopy methods, we provide the first evidence that TiO2nanoparticles in vivo do not penetrate through the intact epidermal barrier. However, we also report that TiO2, when exposed directly to cell cultures in vitro, exerts significant and cell-type dependent effects on such cellular functions as viability, proliferation, apoptosis and differentiation. Therefore, our novel findings will hopefully inspire one to systemically explore in future, clinically oriented trials whether there is indeed a risk from micronized TiO2-containing products on skin with an impaired stratum corneum barrier function.

Calcium distribution in the vessel wall and intima-media thickness of the human carotid arteries.

Increased common carotid artery (CCA) intima-media thickness (IMT) measured by B-mode ultrasound is an early marker of the atherosclerotic process. Arterial calcification is not clearly understood. Using the particle-induced X-ray emission (PIXE) method, we have looked for the location in the artery wall where calcium accumulated in the early phase of atherosclerosis. Twelve segments of CCAs of deceased stroke patients were investigated. In-vivo, carotid duplex ultrasound was performed with bilateral CCA IMT measurement at plaque-free sections. During autopsy, segments of carotid arteries were collected and filled under pressure with a stained histologic embedding material. The frozen arteries were cut into 60-microm-thick slices. Calcium distribution maps from the segments of arteries were determined by PIXE method. IMT measured by ultrasound and calcium distribution maps measured by PIXE were compared. In our cross-sectional study, using the PIXE analysis and ultrasound images, we could demonstrate early calcium accumulation in the media layer. Our results have also shown a significant relationship between calcium content of distributional maps measured by PIXE analysis and corresponding IMT on B-mode ultrasound images of human CCAs.