19 research outputs found

    Regulating the mobility of Cd, Cu and Pb in an acid soil with amendments of phosphogypsum, sugar foam, and phosphoric rock

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    11 pages, figures, and tables statistics.When acid soil has been contaminated by metals as a result of industrial discharges, accidental spills, or acid mine drainage it may be desirable to retain the metals in the soil rather than allow them to leach away. We have investigated the potential of phosphogypsum (PG), sugar foam (SF), and phosphoric rock (PR) to regulate the availability and mobility of Pb, Cd and Cu. We have also identified changes in attenuation during incubation for 1 year and the effect of aging on metal speciation in amended soils. We studied miscible displacement in columns of undisturbed soil previously treated with solutions of the amendments and soluble metals and, subsequently, single and sequential chemical metal extractions. All amendments increased the soil’s metal retention capacity. This, in turn, increased the amount of metal extractable by diethylenetriaminepentaacetic acid (DTPA). However, over time the amounts of DTPAextractable metal decreased, particularly for Cu and Pb. Both Cu and Cd were held preferentially within the acetic acid-extractable fraction (operationally defined exchangeable fraction – EX fraction), whereas Pb was associated mainly with the hydroxylammonium-extractable fraction (operationally defined bound to Fe and Al hydroxides – OX fraction). Both Pb and Cu in the oxide and organic fractions increased in the PG- and SF-treated soils. In general, the distribution of metal did not change in the PR-treated columns after the incubation. Finally, scanning electron microscopy in back-scattered electron mode (SEM–BSE) showed the formation of Al-hydroxy polymers which provides the soils with additional cation sorption capacity. In the PG- and PR-treated columns, P and S were associated with these formations. The three metals were associated with the Al polymers, probably through direct coordination or the formation of ternary complexes with the inorganic ligands phosphate and sulphate.This research was supported by the Spanish Ministry of Science and Technology within the framework of the research project AGL2002-04545-C03-01. We are especially grateful to Laura Barrios for her assistance in the statistical treatment of the data, to Fertiberia, S.A. and Azucarera Ebro, S.L. for supplying us with samples of phosphogypsum and sugar foam, respectively, and to Guoping Lu, anonymous referees and the Editors for their review and comments.Peer reviewe

    Envelhecimento (in)ativo e desenvolvimento emocional em reclusos

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    Este projeto pretende apresentar o contributo do programa de Exercício Físico e do Desenvolvimento Emocional nos reclusos. Para isso optamos por desenvolver um estudo de carácter Quantitativo, Exploratório, Quasi - Experimental, Longitudinal e Descritivo. A amostra é constituída por 20 reclusos do Estabelecimento Prisional de Izeda, com idade média de 41,10±10,19 anos, distribuída entre os 24 e os 67 anos. Dos 20 reclusos, 9 foram designados para integrarem o Grupo de Investigação e os restantes o Grupo de Controlo. A seleção foi feita de forma aleatória. O Grupo de Investigação foi submetido a um programa de atividades de duas a três sessões semanais, durante 8 semanas, tendo cada sessão a duração de 1:15 Horas. Foi aplicada a escala EVCE e o questionário SF-36v2, com a complementaridade das avaliações do estado funcional dos reclusos. As características psicométrica obtidas na escala EVCE e no questionário SF-36v2 permitem-nos verificar que neste estudo se obtem uma boa consistência interna. Após a realização das sessões de intervenção, verificamos que não houve alterações estatisticamente significativas entre os parâmetros do Grupo de Controlo e o Grupo de Investigação. Desta forma, podemos concluir que o programa de intervenção teria melhores resultados se tivesse uma duração maior ao longo do tempo.This project aims to present the contribution of an Exercise Program and of an Emotional Development Program in prison. For this study we chose to develop a Quantitative Explorational, Quasi - Experimental, Descriptive and Longitudinal. The sample consists of 20 inmates of the Izeda Prison, with a mean age of 41.10± 10.19 years, distributed between 24 and 67 years. Of the 20 inmates, nine were appointed to serve on the Research Group and the remaining To the Control Group. The selection was done randomly. The Research Group has undergone program of activities two to three times per week for 8 weeks, with each session lasting 1h15m. EVCE scale and SF-36v2 were applied, the functional status of the inmates was assessed. The psychometric characteristics obtained in EVCE scale and SF-36v2 allow us to verify that this study gives a good internal consistency. After completion of intervention sessions, we found that there were no statistically significant changes between the parameters of the Control Group and Research Group. Thus, we can conclude that the intervention program would have better results if it had a longer duration over tim

    The Cyclophilin-Binding Agent Sanglifehrin A Is a Dendritic Cell Chemokine and Migration Inhibitor

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    Sanglifehrin A (SFA) is a cyclophilin-binding immunosuppressant but the immunobiology of action is poorly understood. We and others have reported that SFA inhibits IL-12 production and antigen uptake in dendritic cells (DC) and exhibits lower activity against lymphocytes. Here we show that SFA suppresses DC chemokine production and migration. Gene expression analysis and subsequent protein level confirmation revealed that SFA suppressed CCL5, CCL17, CCL19, CXCL9 and CXCL10 expression in human monocyte-derived DC (moDC). A systems biology analysis, Onto Express, confirmed that SFA interferes with chemokine-chemokine receptor gene expression with the highest impact. Direct comparison with the related agent cyclosporine A (CsA) and dexamethasone indicated that SFA uniquely suppresses moDC chemokine expression. Competitive experiments with a 100-fold molar excess of CsA and with N-Methyl-Val-4-cyclosporin, representing a nonimmunosuppressive derivative of CsA indicated chemokine suppression through a cyclophilin-A independent pathway. Functional assays confirmed reduced migration of CD4+ Tcells and moDCs to supernatant of SFA-exposed moDCs. Vice versa, SFA-exposed moDC exhibited reduced migration against CCL19. Moreover, SFA suppressed expression of the ectoenzyme CD38 that was reported to regulate DC migration and cytokine production. These results identify SFA as a DC chemokine and migration inhibitor and provide novel insight into the immunobiology of SFA

    Hierarchical Assembly of Star Polymer Polymersomes into Responsive Multicompartmental Microcapsules

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    We report a novel approach to realizing programmable encapsulation and following release of different compounds in a sequential way from multicompartmental microcapsules assembled from preformed polymersomes. The polymersomes, or polymeric vesicles, are formed through electrostatic interactions between a cationic miktoarm star polymer, namely poly­(ethylene oxide)<sub>113</sub>-(quaternized poly­(2-(dimethylamino)­ethyl methacrylate)<sub>60</sub>)<sub>4</sub>, and a linear anionic polyelectrolyte, (poly­(styrenesulfonate)<sub>20</sub>), and then used as the main component to fabricate microcapsules with tannic acid via hydrogen-bonded layer-by-layer assembly. The hydrogen bonding between tannic acid and polymersomes is sensitive to external pH, and the structure of the polymersomes strongly depends on the ionic strength of the surrounding media. This combination facilitates dual-responsive behavior of these multicompartmental polymersome-based microcapsules with the programmable release of two different types of encapsulated molecules (anionic and cationic molecules) from core and shell regions of the microcapsules independently. The integration of responsive nanocarriers into functional microcapsules provides a new way to fabricate multiresponsive hierarchical microstructures with programmed sequential release of different molecules

    Toward Copolymers with Ideal Thermosensitivity: Solution Properties of Linear, Well-Defined Polymers of <i>N</i>‑Isopropyl Acrylamide and <i>N</i>,<i>N</i>‑Diethyl Acrylamide

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    Statistical copolymers of <i>N</i>-isopropyl acrylamide (NIPAM) and <i>N,N</i>-diethyl acrylamide (DEAAM) show a pronounced synergistic depression in their cloud points, though both homopolymers phase separate at significantly higher temperatures close to 30 °C (e.g., <i>Polymer</i> <b>2009</b>, <i>50</i>, 519). While phase separation occurs at 20 °C for the statistical copolymers, the influence of the monomeric sequential arrangement along the backbone was not addressed so far. Thus, we report on the thermosensitive properties of a diblock copolymer PDEAAM-<i>b</i>-PNIPAM and compare it to the homopolymers, mixtures thereof, and to the statistical copolymer of the same molecular weight. These polymers were prepared by controlled radical polymerization, namely Reversible Addition–Fragmentation Chain Transfer (RAFT). Their solution behavior was mainly studied by infrared spectroscopy (IR) of the amide I′ band and by turbidimetry. IR spectroscopy sees a decreasing hydration with heating even below the cloud point for all polymers. This results finally in phase separation, which induces further spectral changes. Rather unexpectedly, the diblock copolymer shows phase separation at temperatures close to the homopolymers, well above the cloud points of the homopolymer mixtures. In turn, the transition temperature of the homopolymer mixture is reduced compared to its homopolymers, which indicates intermolecular attraction between both partners. This behavior can be explained by taking the block length dependencies of the respective cloud points into account and assuming a rather independent phase behavior of each short block (within the copolymer). Then, the increased inherent cloud point of each “half-length” block (compared to the homopolymers) has a stronger effect than the aggregating tendency inherited by the connectivity of the comonomer units. As a result, IR spectroscopy reveals almost ideal behavior of the diblock copolymer, which can be comprehended as an ideal mixture of the homopolymers, each one contributing to the overall signal by its concentration. Finally, <sup>1</sup>H NMR suggests that intermediate aggregation (as seen by light scattering) is not induced by segregation of just one block, but rather by partial and weak complexation between the two components within the diblock copolymer
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