Litteras arena conspergere. Uncovering blotting sands on the Portuguese Inquisition documents

Historical and archival research focused on the Portuguese Inquisition documents (1551–1800) uncovered the use of arena known as blotting sands, a writing accessory used to hasten ink drying. We present in this work the first systematic study combining image analysis, SEM/EDS and µ-Raman techniques, statistics and chemometrics to characterise the blotting sands used by the Portuguese Inquisition and hypothesise their provenance. Iron-titanium and iron oxide minerals categorised as texturally mature sands are the dominant species, consistent with sediment extraction from fluvial or beach contexts and later processed. Chemometrics unveiled time period trends by clustering the samples according to morphology and composition data. This work constitutes a groundbreaking step towards uncovering this intricate writing tool

Surveying an activated sludge reactor using online UV-visible and NIR spectroscopy and chemometrics

The performance of activated sludge reactors can be enhanced by the ability to monitor the status of the process without the need for chemicals addition or complex calibration procedures. Nowadays automation is still limited by poor sensor performance and high maintenance costs. Spectroscopic methods associated with chemometrics are being presented as a powerful tool for process monitoring and control. Once implemented, the method is fast, non-destructive and it can be implemented online, permitting to rapidly infer about the status of the process being monitored. In this work, UV-Visible and Near Infra-Red (NIR) Spectroscopy were used to monitor an activated sludge reactor using immersion probes that were connected to the respective spectrophotometers using optical fibbers. During the monitoring period, changes were induced in the system to test the ability of the monitoring scheme to detect them. The results obtained so far show that it is possible to clearly detect changes in the influent composition as well as the effects of a sudden increase in the influent flow which are among the most common problems that can disturb a biological WWT system. The use of the NIR range for this application is not as common as the UV-Visible range and a direct comparison will allow taking conclusions about the advantages and/or disadvantages of one compared to the other

Monitoring biological wastewater treatment processes: Recent advances in spectroscopy applications

Biological processes based on aerobic and anaerobic technologies have been continuously developed to wastewater treatment and are currently routinely employed to reduce the contaminants discharge levels in the environment. However, most methodologies commonly applied for monitoring key parameters are labor intensive, time-consuming and just provide a snapshot of the process. Thus, spectroscopy applications in biological processes are, nowadays, considered a rapid and effective alternative technology for real-time monitoring though still lacking implementation in full-scale plants. In this review, the application of spectroscopic techniques to aerobic and anaerobic systems is addressed focusing on UV--Vis, infrared, and fluorescence spectroscopy. Furthermore, chemometric techniques, valuable tools to extract the relevant data, are also referred. To that effect, a detailed analysis is performed for aerobic and anaerobic systems to summarize the findings that have been obtained since 2000. Future prospects for the application of spectroscopic techniques in biological wastewater treatment processes are further discussed.The authors thank the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors also acknowledge the financial support to Daniela P. Mesquita and Cristina Quintelas through the postdoctoral Grants (SFRH/BPD/82558/2011 and SFRH/BPD/101338/2014) provided by FCT - Portugal.info:eu-repo/semantics/publishedVersio

Structure of Microemulsion−ABA Triblock Copolymer Networks

Structural equilibrium properties of transient networks formed by microemulsion droplets and ABA triblock copolymers in solution have been studied by Monte Carlo simulation. The droplets were represented by soft spheres, and the polymers were represented by junctions connected by harmonic bonds with an angular potential regulating the intrinsic chain stiffness. The interaction parameters were selected such that the end A-blocks were localized inside the droplets and the middle B-block in the continuous phase. The influence of (i) the polymer concentration, (ii) the polymer stiffness, and (iii) the contour length of the middle B-block on the formation and the structure of the microemulsion−polymer network were investigated using polymer end-to-end separation probability distribution functions, droplet radial distribution functions, droplet-droplet nearest-neighbor probability distribution functions, and network connectivity indicators. An increase of the polymer−droplet number ratio had a strong impact on the network formation. Under typical conditions and at an intermediate polymer−droplet number ratio, (i) the fraction of polymers forming bridges between droplets increased from essentially zero to unity and (ii) the fraction of polymers that were forming loops decreased as the ratio of the polymer end-to-end separation and the surface-to-surface separation between neighboring droplets for a hypothetical homogeneous droplet distribution was increased from 0.5 to 2. For long and flexible polymers, a mesoscopic segregation triggered by a depletion attraction between droplets appeared, and, furthermore, for sufficiently stiff chains, only bridge conformations occurred. The percolation probability could be represented as a function of the average droplet cluster size only, across all systems

Cation Association with Sodium Dodecyl Sulfate Micelles As Seen by Lanthanide Luminescence

The interaction of trivalent lanthanides with sodium dodecyl sulfate micelles (SDS) in aqueous solution has been studied by a variety of experimental techniques. Potentiometric measurements with a sodium selective electrode, steady-state fluorescence spectra of Ce(III), emission lifetime measurements of Ce(III), Tb(III), and Eu(III), and electronic paramagnetic resonance spectra (EPR) of Gd(III) all show that the lanthanide ions bind to the micellar surface. From analysis of the Tb(III) lifetime measurements in water and D2O solutions, it is found that the lanthanide ions lose one hydration water on binding to SDS. However, the EPR measurements suggest that the lanthanide ions still have considerable freedom of movement. Energy transfer between Ce(III) and Tb(III) has been used to obtain further information on multiple lanthanide ion binding. From steady-state fluorescence measurements in aqueous solution in the absence of SDS no energy transfer is observed, although there is quenching of Tb(III) emission by Ce(III), which is found to follow good Stern-Volmer kinetics. In the presence of SDS micelles, very different behavior is observed and energy transfer occurs from excited Ce(III) to Tb(III). This is only possible when the two ions are on the same micelle. The energy transfer phenomena is highly dependent on micelle concentration and has been analyzed theoretically via a Monte Carlo simulation. This shows that the lanthanide ions bind close to the micelle surface, and are consistent with the loss of a water molecule. Also, assuming a Dexter-type model in which the energy transfer intensity is proportional to the inverse of the square root of the average distance between cerium and the closest terbium it is possible to reproduce qualitatively the experimental cerium(III)-sensitized Tb(III) luminescence intensity data

Multi-analytical characterisation of blotting sands on documents from religious orders in Portugal (16th-19th centuries)

Too little is known about areia de escrever, i.e., blotting sands, the intriguing particles sprinkled on freshly written scripts to accelerate the drying time of the ink. Blotting sands constitute a valuable but underestimated historical source. This work investigated the blotting sands used on the account books of the religious houses scattered across continental Portugal and Madeira Island (16th-19th centuries). The sands were mainly composed of different minerals, predominately black sands, but in a few cases, minerals were found mixed with gums, paper cocoons or bone shavings. The combined use of SEM-EDS, μ-Raman and FT-IR techniques uncovered the materials’ chemical or mineralogical composition and morphology. This approach, allied with image analysis and statistics complemented with multivariate analysis, allowed us to look for trends between the samples and hypothesise about their provenance. Heavy minerals, such as ilmenite, hematite and almandine, were identified as major components, together with other silicates (e.g. quartz). Samples were dominated by medium-sized grains with shape features indicating texturally mature sediments resulting from a medium-to-long sedimentary transport. Due to shorter geological transport distances, Madeira Island was the exception, with more angular grains. This work allowed us to uncover blotting sands, value them as historical sources, and establish a roadmap for their use in Portugal, aiming to pave the way towards a more global context in Europe

New insight into the discrimination between omeprazole enantiomers by cyclodextrins in aqueous solution

We report results regarding the use of 1H-NMR spectroscopy in the study of the conformational behaviour and optical activity of omeprazole. Changes in the chemical shifts of chosen atoms reveal that the conformational behaviour of omeprazole is temperature and pH sensitive. Separation and identification of omeprazole enantiomers in the presence of natural and derivative cyclodextrins, such as ß-cyclodextrin (ßCD) and methyl-ß-cyclodextrin (MßCD) are achieved using 1H-NMR spectroscopy, with information from molecular dynamics simulation. This work shows that ßCD includes preferentially R-(–)-omeprazole, acting as a chiral selector. This discrimination of omeprazole enantiomers by cyclodextrins allows development of pharmaceutical formulations with a better bioavailability profile

Coil-globule Coexistence and Compaction of DNA Chains

In this work we discuss different factors governing coil-globule coexistence in the compaction process of DNA. We initially analyse the role played by fluctuations in the degree of binding of an external compacting agent in the conformational behavior of the chain backbone. The analysis relies both on Monte Carlo simulation results and simple statistical approaches. Compacting agents of various binding characteristics are taken into consideration and the degree of charge neutralization upon the chain is related to conformational indicators. Selected model systems comprising stiff chains in the presence of multivalent ions are employed to assess intrinsic single-chain conformational fluctuation, in the presence of external agents but not resulting from differences in binding. It is shown that trends found for a variety of compacting agents, including the extension of the coil-globule coexistence regions, can be ratio-nalised on the basis of this analysis