Sequential determination of traces of As, Sb and hg by on-line magnetic solid phase extraction coupled with Hr-Cs-Cvg-Gfaas

A green and rapid method was developed for the simultaneous separation/preconcentration and sequential monitoring pf arsenic, antimony and mercury by flow injection magnetic solid phase extraction coupled with on-line chemical vapor generation and determination by high resolution continuum source graphite furnace atomic absorption spectrometry. The system is based on chelating/cationic retention of the analytes onto a magnet based reactor designed to contain functionalized magnetic nanoparticles (MNPs). The MNP score allows overcoming the back-pressure problems that usually happen in SPME methods with NPs thanks to the possibility of inmobilizing the MNPs by applying an external magnetic field. Several chemical and flow variables were considered as factors in the optimization process using central composite designs. With the optimized procedure the detection limits obtained were 0.2, 0.003 and 0.4 µg/L for As, Sb and Hg respectively. For the quality control of the analytical performance and the validation of the developed method the analysis of two certified samples TM 24.3 and TMDA 54.4 Fortified Lake Waters was addressed. The results showed good agreement with the certified values.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Syndecan-4/PAR-3 signaling regulates focal adhesion dynamics in mesenchymal cells.

Syndecans regulate cell migration thus having key roles in scarring and wound healing processes. Our previous results have shown that Thy-1/CD90 can engage both αvβ3 integrin and Syndecan-4 expressed on the surface of astrocytes to induce cell migration. Despite a well-described role of Syndecan-4 during cell movement, information is scarce regarding specific Syndecan-4 partners involved in Thy-1/CD90-stimulated cell migration. Mass spectrometry (MS) analysis of complexes precipitated with the Syndecan-4 cytoplasmic tail peptide was used to identify potential Syndecan-4-binding partners. The interactions found by MS were validated by immunoprecipitation and proximity ligation assays. The conducted research employed an array of genetic, biochemical and pharmacological approaches, including: PAR-3, Syndecan-4 and Tiam1 silencing, active Rac1 GEFs affinity precipitation, and video microscopy. We identified PAR-3 as a Syndecan-4-binding protein. Its interaction depended on the carboxy-terminal EFYA sequence present on Syndecan-4. In astrocytes where PAR-3 expression was reduced, Thy-1-induced cell migration and focal adhesion disassembly was impaired. This effect was associated with a sustained Focal Adhesion Kinase activation in the siRNA-PAR-3 treated cells. Our data also show that Thy-1/CD90 activates Tiam1, a PAR-3 effector. Additionally, we found that after Syndecan-4 silencing, Tiam1 activation was decreased and it was no longer recruited to the membrane. Syndecan-4/PAR-3 interaction and the alteration in focal adhesion dynamics were validated in mouse embryonic fibroblast (MEF) cells, thereby identifying this novel Syndecan-4/PAR-3 signaling complex as a general mechanism for mesenchymal cell migration involved in Thy-1/CD90 stimulation. The newly identified Syndecan-4/PAR-3 signaling complex participates in Thy-1/CD90-induced focal adhesion disassembly in mesenchymal cells. The mechanism involves focal adhesion kinase dephosphorylation and Tiam1 activation downstream of Syndecan-4/PAR-3 signaling complex formation. Additionally, PAR-3 is defined here as a novel adhesome-associated component with an essential role in focal adhesion disassembly during polarized cell migration. These novel findings uncover signaling mechanisms regulating cell migration, thereby opening up new avenues for future research on Syndecan-4/PAR-3 signaling in processes such as wound healing and scarring

Orbital Nature of Carboionic Monoradicals Made from Diradicals

The electronic, optical, and solid state properties of a series of monoradicals, anions and cations obtained from starting neutral diradicals have been studied. Diradicals based on s-indacene and indenoacenes, with benzothiophenes fused and in different orientations, feature a varying degree of diradical character in the neutral state, which is here related with the properties of the radical redox forms. The analysis of their optical features in the polymethine monoradicals has been carried out in the framework of the molecular orbital and valence bond theories. Electronic UVVis-NIR absorption, X-ray solid-state diffraction and quantum chemical calculations have been carried out. Studies of the different positive-/negative-charged species, both residing in the same skeletal π-conjugated backbone, are rare for organic molecules. The key factor for the dual stabilization is the presence of the starting diradical character that enables to indistinctively accommodate a pseudo-hole and a pseudoelectron defect with certainly small reorganization energies for ambipolar charge transport.The authors thank the Spanish Ministry of Science and Innovation (projects MINECO/FEDER PGC2018-098533-B-100 and PID2021-127127NB-I00) and the Junta de Andalucía, Spain (UMA18FEDERJA057 and Proyecto de Excelencia PROYEXCEL- 00328). We also thank the Research Central Services (SCAI) of the University of Málaga and the US National Science Foundation (CHE-1954389 to M.M.H., CHE-2003411 to M.A. P.). F.N and Y.D. acknowledge support from “Valutazione della Ricerca di Ateneo” (VRA)-University of Bologna. Y.D. acknowledges Ministero dell’Università e della Ricerca (MUR) for her Ph.D. fellowship. Funding for open access charge: Universidad de Málaga / CBU

Simultaneous determination of V, Ni, Ga and Fe in fuel fly ash using solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry

A green and simple method has been proposed in this work for the simultaneous determination of V, Ni, Ga and Fe in fuel ash samples by solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry (SS HR CS GFAAS). The application of fast programs in combination with direct solid sampling allows eliminating pretreatment steps, involving minimal manipulation of sample. Iridium treated platforms were applied throughout the present study, enabling the use of aqueous standards for calibration. Correlation coefficients for the calibration curves were typically better than 0.9931. The concentrations found in the fuel ash samples analyzed ranged from 0.66 to 4.2 % for V, 0.23 to 0.7 % for Ni, 0 to 5.4 mg/Kg for Ga and 0.10 to 0.60 % for Fe. Precision (%RSD) were 5.2, 10.0, 20.0 and 9.8% for V, Ni, Ga and Fe, respectively, obtained as the average of the %RSD of six replicates of each fuel ash sample. The optimum conditions established were applied to the determination of the target analytes in fuel ash samples. In order to test the accuracy and applicability of the proposed method in the analysis of samples, five ash samples from the combustion of fuel in power stations, were analysed. The method accuracy was evaluated by comparing the results obtained using the proposed method with the results obtained by ICP OES previous acid digestion. The results showed good agreement between them

Strong floristic distinctiveness across Neotropical successional forests.

Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (<20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained

Strong floristic distinctiveness across Neotropical successional forests

Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained

Dilution effect on the slow relaxation of a luminescent dysprosium Metal-Organic Framework based on 2,5-dihydroxyterephthalic acid

A new dysprosium based Metal-Organic Framework with {[Dy(dhbdc)(DMF)]·DMF} formula has been obtained from solvothermal reaction with 2,5-dihydroxyterephthalic acid ligand and dysprosium chloride. This coordination polymer has been characterized and its crystal structure has been solved by X-ray diffraction methods elucidating a three-dimensional network. Magnetic studies of this compound reveal the existence of weak antiferromagnetic interactions among the metal ions with θ value of −0.26 K. Dynamic ac magnetic susceptibility measurements were carried out under an external dc field of 1 kOe, highlighting that at high frequencies two relaxation processes can be observed. However, when studying the diamagnetically diluted analogue 1, a single relaxation process was detected highlighting the effect of the weak but not negligible exchange interactions. Finally, photoluminescence measurements were performed at different temperatures with the aim of getting a more representative characterization of the emissive performance of the material for potential applications in lighting and thermometry.Financial support was given by Junta de Andalucía (Spain) (project number FQM-394 and FQM-1484), University of the Basque Country (GIU 17/13), Gobierno Vasco/Eusko Jaurlaritza (IT1005-16) and the Spanish Ministry of Economy and Competitiveness (MCIU/AEI/FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-B-C21 and CTQ-2015-64049-C3-3R). The authors thank for technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF). A.Z.-L. is grateful to the Government of the Basque Country for the predoctoral fellowshi

Adsorption and degradation of rhodamine B and bromocresol green by FeOCl under advanced oxidation process

FeOCl has gained popularity as a heterogeneous catalyst for pollutant removal in the Fenton process. However, humidification and adsorption of FeOCl are usually not considered in the process. In this way, the adsorption and Fenton activity using rhodamine B (RhB, cationic compound) and bromocresol green (BCG, anionic compound) as pollutants models, at various pH were studied (2, 3.6, 7, and 10). These studies show a very low adsorption level for RhB only at pH 10; therefore, the removal was due to the Fenton reaction. For BCG, at pH 10 the adsorption is almost zero, and at pH 7 after 240 min the adsorption was almost complete, at pH 7, the dye removal by adsorption is akin to Fenton, therefore, at this pH, the remotion was entirely attributed to adsorption. The solution’s removal is the result of the adsorption and Fenton reaction. Additionally, the photocatalytic and photo-Fenton activity of FeOCl was studied by the removal of RhB from a solution at pH 3.6, removing about 84 and 95% of the dye respectively. Under these circumstances, FeOCl is a potential catalyst that could be used for Fenton, photo-Fenton, and photocatalysis. However, the present paper’s experimental data shows that its activity depends largely on the percentage of humidity in the catalyst and the ionic charge of the contaminant that will be treated by the catalyst once it has been activated by water vapor. Characterization essays, such as XRD, show a match for the synthesized FeOCl and FT-IR shows a peak change in the -OH groups range. This could be a possible explanation for the apparition of free radicals