Polymer micro and nanoparticles containing B(III) compounds as emissive soft materials for cargo encapsulation and temperature-dependent applications

Polymer nanoparticles doped with fluorescent molecules are widely applied for biological assays, local temperature measurements, and other bioimaging applications, overcoming several critical drawbacks, such as dye toxicity, increased water solubility, and allowing imaging of dyes/drug delivery in water. In this work, some polymethylmethacrylate (PMMA), polyvinylpyrrolidone (PVP) and poly(styrene-butadiene-styrene) (SBS) based micro and nanoparticles with an average size of about 200 nm and encapsulating B(III) compounds have been prepared via the reprecipitation method by using tetrahydrofuran as the oil phase and water. The compounds are highly hydrophobic, but their encapsulation into a polymer matrix allows obtaining stable colloidal dispersions in water (3.39 µM) that maintain the photophysical behavior of these dyes. Although thermally activated non-radiative processes occur by increasing temperature from 25 to 80◦C, the colloidal suspension of the B(III) particles continues to emit greenish light (λ = 509 nm) at high temperatures. When samples are cooling back to room temperature, the emission is restored, being reversible. A probe of concept drug delivery study was conducted using coumarin 6 as a prototype of a hydrophobic drug.publishersversionpublishe

Exploring Coumarin-Based Boron Emissive Complexes as Temperature Thermometers in Polymer-Supported Materials

Three coumarin-based boron complexes (L1, L2 and L3) were designed and successfully incorporated into polymeric matrixes for evaluation as temperature probes. The photophysical properties of the complexes were carried out in different solvents and in the solid state. In solution, compound L1 exhibited the highest fluorescence quantum yield, 33%, with a positive solvatochromism also being observed on the absorption and emission when the polarity of the solvent increased. Additionally in the presence of anions, L1 showed a colour change from yellow to pink, followed by a quenching in the emission intensity, which is due to deprotonation with the formation of a quinone base. Absorption and fluorescence spectra of L1 were calculated at different temperatures by the DFT/B3LYP method. The decrease in fluorescence of compound L1 with an increase in temperature seems to be due to the presence of pronounced torsional vibrations of the donor and acceptor fragments relative to the single bond with C(carbonyl)-C (styrene fragment). L1, L2 and L3, through their incorporation into the polymeric matrixes, became highly emissive by aggregation. These dye@doped polymers were evaluated as temperature sensors, showing an excellent fluorescent response and reversibility after 15 cycles of heating and cooling

Bivalve distribution in hydrographic regions in South America: historical overview and conservation

Based on literature review and malacological collections, 168 native freshwater bivalve and five invasive species have been recorded for 52 hydrographic regions in South America. The higher species richness has been detected in the South Atlantic, Uruguay, Paraguay, and Amazon Brazilian hydrographic regions. Presence or absence data were analysed by Principal Coordinate for Phylogeny-Weighted. The lineage Veneroida was more representative in hydrographic regions that are poorer in species and located West of South America. The Mycetopodidae and Hyriidae lineages were predominant in regions that are richest in species toward the East of the continent. The distribution of invasive species Limnoperna fortunei is not related to species richness in different hydrographic regions there. The species richness and its distribution patterns are closely associated with the geological history of the continent. The hydrographic regions present distinct phylogenetic and species composition regardless of the level of richness. Therefore, not only should the richness be considered to be a criterion for prioritizing areas for conservation, but also the phylogenetic diversity of communities engaged in services and functional aspects relevant to ecosystem maintenance. A plan to the management of this fauna according to particular ecological characteristics and human uses of hydrographic regions is needed.Facultad de Ciencias Naturales y Muse

Determinación y evaluación de los componentes presentes en las pinturas anti-incrustantes utilizadas en la acuicultura y sus posibles efectos en sedimentos marinos en el sur de Chile

Se realizaron muestreos de sedimento en tres áreas relacionadas con el uso de pinturas anti-incrustantes en la salmonicultura en el sur de Chile, con el fin de detectar alteraciones en la abundancia o diversidad de la macrofauna bentónica debidas a la acumulación de metales como Cu y Zn en los sedimentos. Los resultados muestran que existe acumulación especialmente de Cu en los sedimentos aledaños a las balsas jaulas de cultivo, pero no se apreciaron variaciones significativas en la composición ni en la abundancia de la macrofauna bentónica asociada a estos centros de cultivo, aun cuando las concentraciones de Cu superaron los 800 μg g-1 en el sedimento

Determinación y evaluación de los componentes presentes en las pinturas anti-incrustantes utilizadas en la acuicultura y sus posibles efectos en sedimentos marinos en el sur de Chile

Se realizaron muestreos de sedimento en tres áreas relacionadas con el uso de pinturas anti-incrustantes en la salmonicultura en el sur de Chile, con el fin de detectar alteraciones en la abundancia o diversidad de la macrofauna bentónica debidas a la acumulación de metales como Cu y Zn en los sedimentos. Los resultados muestran que existe acumulación especialmente de Cu en los sedimentos aledaños a las balsas jaulas de cultivo, pero no se apreciaron variaciones significativas en la composición ni en la abundancia de la macrofauna bentónica asociada a estos centros de cultivo, aun cuando las concentraciones de Cu superaron los 800 μg g-1 en el sedimento

Mesomorphism and luminescence in coordination compounds and ionic salts based on pyridine-functionalized β-diketones. Influence of the pyridine nitrogen position

Funding Information: This research was funded by Comunidad de Madrid (project B2017/BMD-3770-CM), as well as the Associate Laboratory for Green Chemistry - LAQV which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020) as well as the Scientific Society PROTEOMASS (Portugal) for funding support (Funding Grant 2022). F.D. thanks to FCT/MEC (Portugal) for his doctoral grant reference 2021.05161.BD. Special thanks to Dr. Jakub M. Wojciechowski (Senior Application Scientist, Rigaku Europe SE) for his help during the experiments carried out for compound 11 . Publisher Copyright: © 2023 The Author(s)Pyridine-functionalized β-diketones with the pyridine nitrogen atom at 3 or 4 position (L3N and L4N, respectively) have been used as building blocks to obtain two new families of compounds with mesomorphic and luminescent behaviors. The N-pyridine coordination of the β-diketones to zinc(II), palladium(II) and platinum(II) metal centers has allowed to synthesize neutral coordination compounds of the type [MCl2(LZN)2] (M = Zn(II), Pd(II), Pt(II); Z = 3, 4). Particularly, coordination of L4N towards Pt(II) gives rise to the cationic species [Pt(NH3)2(L4N)2]2+. Otherwise, protonation of the pyridine moiety was strategically used to obtain a novel series of pyridinium ionic salts of the type (HLZN)nA (n = 1, A = Cl; n = 2, A = MCl4, M = Zn(II), Pd(II), Pt(II); Z = 3, 4). The neutral or ionic nature of the complexes, as well as the β-diketone ligands and the metal center in both the neutral and anionic complexes, has a great influence on the mesomorphic behavior. Thus, columnar or smectic mesophases can be selectively formed. Single-crystal and temperature-dependent powder X-ray diffraction studies have been performed to analyze the molecular packing in the crystal and the supramolecular ordering in the mesophase. All the aforementioned factors also play a key role on the luminescence properties, the Zn(II) coordination compounds and ionic salts being the best candidates as bifunctional materials.publishersversionpublishe

Precision timing calorimeter for high energy physics

Scintillator based calorimeter technology is studied with the aim to achieve particle detection with a time resolution on the order of a few 10 ps for photons and electrons at energies of a few GeV and above. We present results from a prototype of a 1.4×1.4×11.4 cm^3 sampling calorimeter cell consisting of tungsten absorber plates and Cerium-doped Lutetium Yttrium Orthosilicate (LYSO) crystal scintillator plates. The LYSO plates are read out with wave lengths shifting fibers which are optically coupled to fast photo detectors on both ends of the fibers. The measurements with electrons were performed at the Fermilab Test Beam Facility (FTBF) and the CERN SPS H2 test beam. In addition to the baseline setup plastic scintillation counter and a MCP-PMT were used as trigger and as a reference for a time of flight measurement (TOF). We also present measurements with a fast laser to further characterize the response of the prototype and the photo sensors. All data were recorded using a DRS4 fast sampling digitizer. These measurements are part of an R&D program whose aim is to demonstrate the feasibility of building a large scale electromagnetic calorimeter with a time resolution on the order of 10 ps, to be used in high energy physics experiments

The combined effects of ocean acidification and warming on a habitat-forming shell-crushing predatory crab

In mid rocky intertidal habitats the mussel Perumytilus purpurarus monopolizes the substratumto the detriment of many other species. However, the consumption of mussels by the shell-crushing crab Acanthocyclus hassleri creates within the mussel beds space and habitat for several other species. This crab uses its disproportionately large claw to crush its shelled prey and plays an important role in maintaining species biodiversity. This study evaluated the consequences of projected near-future ocean acidification (OA) and warming (OW) on traits of A. hassleri linked with their predatory performance. Individual A. hassleri were maintained for 10-16 weeks under contrasting pCO(2) (similar to 500 and 1400 mu atm) and temperature (similar to 15 and 20 degrees C) levels. We compared traits at the organismal (oxygen consumption rate, survival, calcification rate, feeding rates, crusher claw pinching strength, self-righting speed, sarcomere length of the crusher claw muscles) and cellular (nutritional status ATP provisioning capacity through citrate synthase activity, expression of HSP70) level. Survival, calcification rate and sarcomere length were not affected by OA and OW. However, OW increased significantly feeding and, oxygen consumption. Pinching strength was reduced by OA; meanwhile self-righting was increased by OA and OW. At 20 degrees C, carbohydrate content was reduced significantly by OA. Regardless of temperature, a significant reduction in energy reserves in terms of protein content by OA was found. The ATP provisioning capacity was significantly affected by the interaction between temperature and pCO(2) and was highest at 15 degrees C and present day pCO(2) levels. The HSP70 levels of crabs exposed to OW were higher than in the control crabs. We conclude that OAand OWmight affect the amount and size of prey consumed by this crab. Therefore, by reducing the crab feeding performance these stressors might pose limits on their role in generating microhabitat for other rocky intertidal species inhabiting within mussel beds. (C) 2020 Elsevier B.V. All rights reserved