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
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
Este projeto pretende apresentar o contributo do programa de ExercĂcio FĂsico e do Desenvolvimento Emocional nos reclusos. Para isso optamos por desenvolver um estudo de carácter Quantitativo, ExploratĂłrio, Quasi - Experimental, Longitudinal e Descritivo. A amostra Ă© constituĂda por 20 reclusos do Estabelecimento Prisional de Izeda, com idade mĂ©dia de 41,10±10,19 anos, distribuĂda 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 aleatĂłria. O Grupo de Investigação foi submetido a um programa de atividades de duas a trĂŞs sessões semanais, durante 8 semanas, tendo cada sessĂŁo 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 caracterĂsticas psicomĂ©trica obtidas na escala EVCE e no questionário SF-36v2 permitem-nos verificar que neste estudo se obtem uma boa consistĂŞncia interna. ApĂłs a realização das sessões de intervenção, verificamos que nĂŁo 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
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
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 polyÂ(ethylene
oxide)<sub>113</sub>-(quaternized polyÂ(2-(dimethylamino)Âethyl methacrylate)<sub>60</sub>)<sub>4</sub>, and a linear anionic polyelectrolyte, (polyÂ(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
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