Microplastic contamination of lettuces grown in urban vegetable gardens in Lisbon (Portugal).

Urban vegetable gardens are very often a feature of cities that want to offer their citizens a more sustainable lifestyle by producing their own food products. However, cities can have significant pollution levels (or pollution hotspots) due to specific sources of pollution, such as traffic. Among the various pollutants, microplastics (MPs) are emerging as a consensual concern due to the awareness of the environmental contamination, their bioaccumulation potential and human intake, and, consequently unknown human health impacts. The present study compared the content of MPs in lettuce plants cultivated in Lisbon urban gardens with those cultivated in a rural area, as well as samples bought in supermarkets. Microplastics were detected in all washed leaves, with mean levels ranging from 6.3 ± 6.2 to 29.4 ± 18.2 MPs/g. Lettuce grown in urban gardens from areas with high traffic density showed higher MPs levels. Weak positive Spearman's rank correlations were found between MPs content and concentrations of Cu and S (determined by Particle Induced X-Ray Emission, PIXE), suggesting a possible role of traffic contribution to MPs levels, as both elements are considered traffic-source tracers. These results contribute to shed light on the MP contamination of vegetables grown in such urban environments, that may represent a potential MP exposure route through the dietary intake, corresponding to a 70% increase in annual MP intake compared to lettuces bought in supermarkets.

Swiss Stained-Glass Panels: An Analytical Study.

The history and iconography of Swiss stained glass dating between the 16th and 18th centuries are well studied. However, the chemical and morphological characteristics of the glass and glass paints, particularly the nature of the raw materials, the provenance of the glass, and the technology used to produce it are less well understood. In this paper, we studied two sets of samples from stained-glass panels attributed to Switzerland, which date from the 16th to 17th centuries: the first set comes from Pena National Palace collection, the second from Vitrocentre Romont. The aims were to identify the materials used in the production of the glass, to find out more about their production origin and to characterize the glass paints. Both glass and the glass paints were analysed by particle-induced X-ray emission; the paints were additionally analysed by scanning electron microscopy-electron-dispersive X-ray spectroscopy (SEM-EDS). The results show that the glass from both sets was probably produced in the same region and that wood ash was used as a fluxing agent. Different recipes have been used to make the blue enamels. However, the cobalt ore used as a coloring agent in all of the blue enamels came from the mining district in Schneeberg, Germany.

A biocompatible hybrid material with simultaneous calcium and strontium release capability for bone tissue repair.

The increasing interest in the effect of strontium in bone tissue repair has promoted the development of bioactive materials with strontium release capability. According to literature, hybrid materials based on the system PDMS-SiO2 have been considered a plausible alternative as they present a mechanical behavior similar to the one of the human bone. The main purpose of this study was to obtain a biocompatible hybrid material with simultaneous calcium and strontium release capability. A hybrid material, in the system PDMS-SiO2-CaO-SrO, was prepared with the incorporation of 0.05 mol of titanium per mol of SiO2. Calcium and strontium were added using the respective acetates as sources, following a sol-gel technique previously developed by the present authors. The obtained samples were characterized by FT-IR, solid-state NMR, and SAXS, and surface roughness was analyzed by 3D optical profilometry. In vitro studies were performed by immersion of the samples in Kokubo's SBF for different periods of time, in order to determine the bioactive potential of these hybrids. Surfaces of the immersed samples were observed by SEM, EDS and PIXE, showing the formation of calcium phosphate precipitates. Supernatants were analyzed by ICP, revealing the capability of the material to simultaneously fix phosphorus ions and to release calcium and strontium, in a concentration range within the values reported as suitable for the induction of the bone tissue repair. The material demonstrated to be cytocompatible when tested with MG63 osteoblastic cells, exhibiting an inductive effect on cell proliferation and alkaline phosphatase activity.

Imaging of intracellular metal partitioning in marine diatoms exposed to metal pollution: consequences to cellular toxicity and metal fate in the environment.

This study investigates the metal content and compartmentalization changes in whole cells of diatom Coscinodiscus eccentricus exposed to metal overload, examining consequences to cellular toxicity, tolerance mechanisms, and metal fate in the environment. Cells exposed to Ni, Cu and Zn were analysed using nuclear microprobe techniques. Particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS), and scanning transmission ion microscopy (STIM) were used simultaneously to obtain high-resolution imaging of morphological and quantitative elemental distribution data. Elemental partitioning within cell compartments, such as cell wall, cytoplasm and major organelles, was assessed. Diatoms clearly responded to excess metal levels, by changing cytoplasm morphology, concentrating added metals, and altering Fe transport mechanisms. Different metal accumulation patterns indicated high susceptibility to Cu, retained in the cytoplasm, and detoxification capability for Ni and Zn, mobilized to the vacuole. Iron and Zn were accumulated in the siliceous wall. Different metal distributions within the cell imply distinct environmental fates, Cu and Ni remain available with potential for biomagnification through the food web, whereas Fe and Zn are deposited at the bottom through frustule sedimentation.

Ultrastructure of Tuta absoluta parasitized eggs and the reproductive potential of females after parasitism by Metarhizium anisopliae.

Among the microorganisms used in biological control, the muscadine fungus Metarhizium anisopliae (Metsch.) Sorok. is produced and formulated world wide aiming to control pests from several agricultural crops. This work evaluated effects of M. anisopliae isolate UFRPE-6 on the fecundity and mortality of Tuta absoluta (Lepidoptera: Gelechiidae) females and the mechanism of infection on eggs. The infection of the females by the fungus did not affect their oviposition and fecundity; however it affected the survival with total and confirmed mortality of 54.2% and 37.14%, respectively. The eggs were treated with suspension at concentration of 10(6)conidia/mL. The analysis under scanning electron microscopy showed that conidia germination and penetration processes in the eggs of T. absoluta started within the period of 6h after the inoculation. Several hyphal bodies were observed from 12h and an intense extrusion of the mycelium covering all the external surface of the eggs 72h after inoculation. Despite its moderate activity in adults, the isolate URPE-6 of M. anisopliae showed promising in the control of T. absoluta due to its pathogenicity and virulence to eggs from this pest.

Nuclear microscopy: a tool for imaging elemental distribution and percutaneous absorption in vivo.

Nuclear microscopy is a technique based on a focused beam of accelerated particles that has the ability of imaging the morphology of the tissue in vivo and of producing the correspondent elemental maps, whether in major, minor, or trace concentrations. These characteristics constitute a strong advantage in studying the morphology of human skin, its elemental distributions and the permeation mechanisms of chemical compounds. In this study, nuclear microscopy techniques such as scanning transmission ion microscopy and particle induced X-ray emission were applied simultaneously, to cryopreserved human skin samples with the purpose of obtaining high-resolution images of cells and tissue morphology. In addition, quantitative elemental profiling and mapping of phosphorus, calcium, chlorine, and potassium in skin cross-sections were obtained. This procedure accurately distinguishes the epidermal strata and dermis by overlapping in real time the elemental information with density images obtained from the transmitted beam. A validation procedure for elemental distributions in human skin based on differential density of epidermal strata and dermis was established. As demonstrated, this procedure can be used in future studies as a tool for the in vivo examination of trans-epidermal and -dermal delivery of products.