Abstract: The dire previsions of the WHO on the so-called “post-antibiotic era” and the continuous and global rise of anti-microbial resistance, spurs our research community to find better ways to fight these threats. In light of this severe threat to human health many attempts have been made to develop efficient methods to detect antibiotic residues in different streams. The use of electrochemistry seems an inviting approach for on-site and fast monitoring. In this critical review, recent developments in the field of (bio) electro-sensing of 19-lactam antibiotics will be presented, with a focus on aptamers and molecularly imprinted polymers, the two main promises of a new generation of biosensors, yet to be fulfilled.

Abstract: An electrochemical matairesinol biosensor was fabricated by immobilizing tyrosinase on a poly(thionine)/nafion/multi-walled carbon nanotube composite film. A polymeric film of the redox dye thionine enables the stable immobilization of tyrosinase while acting as a mediator for the enzymatic process has been incorporated into the carbon nanotube/nafion composite film. The immobilization method is based on crosslinking of the tyrosinase layer with an electropolymerized film of poly(thionine). The good homogenization of the electron conductor CNTs in the integrated films provides the possibility of a three-dimensional electron conductive network. The biosensor was characterized by electrochemical impedance spectroscopy and electrochemical characterization. The composite electrode exhibits catalytic activity, high sensitivity, stability and is applicable over a wide range of concentrations from 180 nM to 4.33 μM with a detection limit (LOD) of 37 nM. The obtained results suggest that the developed sensor can be successfully used for the determination of phenolic endocrine disruptors over a concentration range covering their environmental levels.

Abstract: Effective CO2-storage in the shallow solid Earth mainly occurs by the formation of carbonates. Although the possibility of transport and storage of carbonates to great depth is demonstrated experimentally, ultra-deep mantle carbonates have not been found before. Applying several in situ analytical techniques on inclusions in diamonds from Juina (Brazil) originating from the lower part of the transition zone (> 580 km) or even the lower mantle (> 670 km), reveal the existence of deep Earth carbonates. These finding unquestionably show that at least locally carbonates exist within the deep Earth and may indicate that the Earth's global CO2-cycle has an ultra-deep extension.

Abstract: The electrochemical detection of non-electroactive contaminants can be successfully faced via the use of indirect detection strategies. These strategies can provide sensitive and selective responses often coupled with portable and user-friendly analytical tools. Indirect detection strategies are usually based on the change in the signal of an electroactive probe, induced by the presence of the target molecule at a modified electrode. This critical review aims at addressing the developments in indirect electro-sensing strategies for non-electroactive contaminants in food and environmental analysis in the last years (2017-2019). Emphasis is given to the strategy design, the electrode modifiers used and the feasibility of technological transfer.

Abstract: This work reports the first systematic chemical characterization of Portuguese 18th century glassware. 28 selected glass fragments, recovered from an archaeological excavation carried out in the site where King D. João V of Portugal established an important glass manufacture, Real Fábrica de Vidros de Coina (Coina Royal Glass Factory), were studied. This factory operated from 1719 until 1747, the year in which the factory was transferred to Marinha Grande. The fragments were analysed by micro-energy dispersive X-ray fluorescence (micro-EDXRF), using a portable spectrometer ArtTAX, and scanning electron microscopy (SEM-EDX). The analytical data showed that a large variety of glass types was manufactured in that factory, namely soda-lime glass, mixed-alkali glass, high lime-low alkali glass, potash glass and lead glass. In general, the composition of the glass varies according to the function of the objects. It was demonstrated that micro-EDXRF can be an important tool to characterize museum glass objects when only in situ non-invasive analytical methods are allowed.

Abstract: Epicuticular wax (EW) protects the plant’s integrity and acts as a barrier against biotic and abiotic stresses. The micro-structured three-dimensional EW’s and presence of leaf trichomes influence the wettability of a leaf surface. In this study, leaves of 96 perennial urban plant species were examined to determine an association between epicuticular wax structure (EWS) types and leaf wettability and investigate their seasonal variation. The EWS types were identified using Scanning Electron Microscopy (SEM), while leaf wettability was analyzed by measuring the drop contact angle (DCA) on both the abaxial and the adaxial sides of leaves collected from a common garden in June and September 2016. Four distinct EWS types namely thin film, platelets, crusts, and tubules were observed on leaves of investigated plant species in both June and September. The EWS types varied significantly between functional plant types and plant families in both June and September. In June, the abaxial DCA ranged from 56° to 147°, and the adaxial DCA ranged from 56° to 136°. In September, the abaxial DCA ranged from 54° to 130°, and the adaxial DCA ranged from 51° to 125°. The effect of time, leaf side, and EWS type on leaf wettability were significant. Plant species which showed a change in EWS type or clustering from June to September did not show a more pronounced reduction in DCA compared to those species which exhibited a constant EWS type. Findings from our study illustrate that DCA is not a good indicator in determining the different EWS types due to overlapping DCA intervals between the identified EWS types. However, the identified EWS types remained fairly stable throughout the in-leaf season and do not require repeated measurements for characterization.

Abstract: The chemical composition, as determined by electron probe X-ray microanalysis of a series of ca. 100 archaeological glass fragments, excavated at the Raversijde site (Belgium) is discussed. In the 15th-16th century, Raversijde was a flourishing fishermen town located on the shore of the North Sea, close to the city of Ostend. As a consequence of several battles that were fought in its vicinity, the site was abandoned in the 16th century and was not occupied since then. It is one of the rare archaeological sites in Europe that contains a significant amount of information on the daily life inside a small but affluent medieval community. A comparison of the chemical composition of fragments of vessels and window glass encountered in Raversijde to those found in urban centres in Belgium and to literature date on German and French archaeological finds shows that glass made with wood ash dominates. Usually, it concerns artifacts with a predominantly utilitarian use. A few objects made with sodic (i.e., Na-rich) glass were also encountered, likely to have been imported from Venice during the 15th century or in later periods from an urban centre such as Antwerp, where Facon-de-Venice glass manufacturing activities were established near the start of the 16th century. (C) 2004 Elsevier B.V. All rights reserved.

Abstract: Since the recent development of a mobile setup, MA-XRF scanning proved a valuable tool for the non-invasive, technical study of paintings. In this work, the applicability of MA-XRF scanning for investigating stained-glass windows inside a conservation studio is assessed by analysis of a high-profile, well-studied late-mediaeval panel. Although accurate quantification of components is not feasible with this analytical imaging technique, plotting the detected intensities of K versus Ca in a scatter plot allowed distinguishing glass fragments of different compositional types within the same panel. In particular, clusters in the Ca/K correlation plot revealed the presence of two subtypes of potash glass and three subtypes of high lime low alkali glass. MA-XRF results proved consistent with previous quantitative SEM-EDX analysis on two samples and analytical-based theories on glass production in the Low Countries formulated in literature. A bi-plot of the intensities of the more energetic Rb-K versus Sr-K emission lines yielded a similar glass type differentiation and is here presented as suitable alternative in case the Ca/K signal ratio is affected by superimposed weathering crusts. Apart from identification of the chromophores responsible for the green, blue and red glass colors, contrasting the associated elemental distribution maps obtained on the exterior and interior side of the glass permitted discriminating between colored pot metal glass and multi-layered flashed glass as well. Finally, the benefit of obtaining compositional information from the entire surface, as opposed to point analysis, was illustrated by the discovery of what appears to be a green cobalt glass a feature that was previously missed on this well-studied stained-glass window, both by connoisseurs and spectroscopic sample analysis. (C) 2015 Elsevier B.V. All rights reserved.