Remediation of Trichloroethylene by FeS-Coated Iron Nanoparticles in Simulated and Real Groundwater: Effects of Water Chemistry

The reactivity of FeS-coated iron nanoparticles (nFe/FeS) toward trichloroethylene (TCE) reduction was examined in both synthetic and real groundwater matrices to evaluate the potential performance of nFe/FeS in field treatment. The rate of TCE reduction increased with increasing pH, which is consistent with the pH effect reported previously for iron sulfide systems, but opposite that has been observed for (nonsulfidic) Fe⁰ systems. The rates of TCE reduction were unaffected by ionic strength over the range of 0.1–10 mM NaCl, increased with Ca²⁺ or Mg²⁺ concentrations, and inhibited by the presence of humic acid. The inhibitory effect of humic acid on the reactivity of nFe/FeS was largely alleviated when humic acid was combined with Ca²⁺/Mg²⁺, presumably due to decreased adsorption of humic acid onto nFe/FeS surface by the formation of humic acid–Ca²⁺/Mg²⁺ complexes

Effects of Metal Ions on the Reactivity and Corrosion Electrochemistry of Fe/FeS Nanoparticles

Nano-zerovalent iron (nZVI) formed under sulfidic conditions results in a biphasic material (Fe/FeS) that reduces trichloroethene (TCE) more rapidly than nZVI associated only with iron oxides (Fe/FeO). Exposing Fe/FeS to dissolved metals (Pd²⁺, Cu²⁺, Ni²⁺, Co²⁺, and Mn²⁺) results in their sequestration by coprecipitation as dopants into FeS and FeO and/or by electroless precipitation as zerovalent metals that are hydrogenation catalysts. Using TCE reduction rates to probe the effect of metal amendments on the reactivity of Fe/FeS, it was found that Mn²⁺ and Cu²⁺ decreased TCE reduction rates, while Pd²⁺, Co²⁺, and Ni²⁺ increased them. Electrochemical characterization of metal-amended Fe/FeS showed that aging caused passivation by growth of FeO and FeS phases and poisoning of catalytic metal deposits by sulfide. Correlation of rate constants for TCE reduction (<i>k</i>_obs) with electrochemical parameters (corrosion potentials and currents, Tafel slopes, and polarization resistance) and descriptors of hydrogen activation by metals (exchange current density for hydrogen reduction and enthalpy of solution into metals) showed the controlling process changed with aging. For fresh Fe/FeS, <i>k</i>_obs was best described by the exchange current density for activation of hydrogen, whereas <i>k</i>_obs for aged Fe/FeS correlated with electrochemical descriptors of electron transfer

Construction of PLGA Nanoparticles Coated with Polycistronic <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i> Genes for Chondrogenesis of Human Mesenchymal Stem Cells

Transfection of a cocktail of genes into cells has recently attracted attraction in stem cell differentiation. However, it is not easy to control the transfection rate of each gene. To control and regulate gene delivery into human mesenchymal stem cells (hMSCs), we employed multicistronic genes coupled with a nonviral gene carrier system for stem cell differentiation. Three genes, <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i>, were successfully fabricated in a single plasmid. This multicistronic plasmid was complexed with the polycationic polymer polyethylenimine, and poly­(lactic-<i>co</i>-glycolic) acid (PLGA) nanoparticles were coated with this complex. The uptake of PLGA nanoparticles complexed with the multicistronic plasmid was tested first. Thereafter, transfection of <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i> was evaluated, which increased the potential for chondrogenesis of hMSCs. The expression of specific genes triggered by transfection of <i>SOX5</i>, <i>SOX6</i>, and <i>SOX9</i> was tested by RT-PCR and real-time qPCR. Furthermore, specific proteins related to chondrocytes were investigated by a glycosaminoglycan/DNA assay, Western blotting, histological analyses, and immunofluorescence staining. These methods demonstrated that chondrogenesis of hMSCs treated with PLGA nanoparticles carrying this multicistronic genes was better than that of hMSCs treated with other carriers. Furthermore, the multicistronic genes complexed with PLGA nanoparticles were more simple than that of each single gene complexation with PLGA nanoparticles. Multicistronic genes showed more chondrogenic differentiation than each single gene transfection methods

Self-Generation of Reactive Oxygen Species on Crystalline AgBiO₃ for the Oxidative Remediation of Organic Pollutants

In this study, we synthesized a novel perovskite nanomaterial consisting of AgBiO₃ nanoparticles (NPs) via an ion-exchange method for remediation of polluted environments. The AgBiO₃ NPs could self-produce significant amounts of reactive oxygen species (ROS) without light illumination or any other additional oxidant due to the controllable release of lattice oxygen from the crystalline AgBiO₃, resulting in the formation of ROS somehow. The self-produced ¹O₂, O₂^•–, and ^•OH were confirmed by electron spin resonance spectroscopy using a spin trap technique. We found that the AgBiO₃ NPs could be reused for the mineraliztion of most recalcitrant organic compounds alone, including Rhodamine B (RhB), phenol, 4-chlorophenol, 2,4-dichlorophenol, and bisphenol A. After the repeated eight cycles of continious treatment of RhB, AgBiO₃ NPs still achieved 79% of degradation after 30 min of treatment. Characterization results revealved that the lattice oxygen inside AgBiO₃ was activated to form active oxygen (O*), which resulted in consecutive formation of ROS. This study provides new insight on the lattice oxygen activation mechanism of silver bismuthate and its application to the remediation of polluted waters

The role of IFN-γ in the CEC-mediated suppression of airway inflammation induced by OVA challenge in wild-type and IFN-γ KO mice.

<p>Mice were sensitized with PBS, OVA or OVA+CEC on days 0 and 7, and then challenged with OVA on days 14, 15, 21 and 22. AHR was determined on day 23, followed by sacrifice of mice for the collection of BAL fluid, sera and lungs on day 24. The infiltration of inflammatory cells into the lung (A), methacholine-induced airway hyperresponsiveness (B), and total (C) and differential cell counts (D) in the BAL fluid were investigated. Wild-type OVA (n = 5), wild-type mice sensitized with OVA; Wild-type OVA+CEC (n = 5), wild-type mice sensitized with OVA and CEC; IFN-γ KO OVA (n = 5), IFN-γ KO mice sensitized with OVA; IFN-γ KO OVA+CEC (n = 5), IFN-γ KO mice sensitized with OVA and CEC. *, <i>P</i><0.01.</p

The suppressive effects of the crude extract of <i>Caenorhabditis elegans</i> (CEC) on established asthma in mice.

<p>Airway inflammation has been induced in mice by sensitization and challenge with OVA using the same protocol as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035447#pone-0035447-g001" target="_blank">Fig. 1</a>, whereas PBS group (n = 5), the negative control group, was sensitized and challenged with PBS. The establishment of asthma was confirmed by measuring AHR after the last challenge with OVA at week 3, and thereafter, mice were divided into four experimental groups and challenged with either OVA or various CEC regimens. PBS group and OVA group (n = 5) were intranasally challenged with PBS or OVA, respectively, at week 4 and 6. CEC M50 (n = 5) and CEC M100 (n = 5) groups were intranasally challenged once with a single dose of 50 µg or 100 µg CEC at week 4. CEC W25 (n = 5) group was intranasally challenged with 25 µg of CEC weekly for one month from week 4 to week 7. At week 8, the methacholine-induced AHR was measured, and then the mice were sacrificed for serum and BAL collection. (A) Airway hyperresponsiveness to methacholine was measured using a whole-body plethysmograph at week 8. Data are presented as the mean ± SD from a single experiment representative of three separate experiments. (B) Total and differential cell counts in the BAL fluid. (C) Analysis of cytokines in the BAL fluid. Data from individual mice are presented as arithmetic means in histograms. *, <i>P</i><0.01.</p

Cytokine analysis of the BAL fluid.

<p>Data from individual mice are presented as arithmetic means in histograms. PBS (n = 5), mice sensitized with PBS and challenged with OVA; OVA (n = 5), mice sensitized and challenged with OVA; OVA+CEC (n = 5), mice sensitized with OVA and CEC and challenged with OVA. *, <i>P</i><0.01.</p

The suppressive effect of the crude extract of <i>Caenorhabditis elegans</i> (CEC) on the development of airway inflammation.

<p>Mice were sensitized with PBS, OVA or OVA+CEC by intraperitoneal injections on days 0 and 7, and then intranasally challenged with OVA on days 14, 15, 21 and 22. AHR was determined on day 23 and mice were sacrificed for the collection of BAL fluid, sera and lungs on day 24. (A) Histopathological observation of the lungs. H&E, ×100. (B) Total cell counts in the BAL fluid. (C) Differential cell counts of BAL cells. (D) Airway hyperresponsiveness to increasing concentration of methacholine presented as airway resistance. Data are presented as the mean ± SD from a single experiment representative of three separate experiments. PBS (n = 5), mice sensitized with PBS and challenged with OVA; OVA (n = 5), mice sensitized and challenged with OVA; OVA+CEC (n = 5), mice sensitized with OVA and CEC and challenged with OVA.*, <i>P</i><0.01. **, <i>P</i><0.05.</p

The evaluation of serum antibody titers in mice with OVA-induced airway inflammation.

<p>The production of total (A) and OVA-specific IgE, IgG1 and IgG2a (B) was evaluated to identify the effects of the <i>C. elegans</i> crude extract. Data from individual mice are presented as arithmetic means in histograms. PBS (n = 5), mice sensitized with PBS and challenged with OVA; OVA (n = 5), mice sensitized and challenged with OVA; OVA+CEC (n = 5), mice sensitized with OVA and CEC and challenged with OVA. *, <i>P</i><0.01. **, <i>P</i><0.05.</p

Correlation analysis between numbers of recovered worms and EPG counts.

<p>Data of egg-positive subjects (n = 50) were used for analysis. The correlation coefficient (Spearman's rho, <i>r</i>) usually presents a weak (<i>r</i><0.5), moderate (0.5<<i>r</i><0.8) and strong (0.8<<i>r</i>) relationship. A Student's t test was used to examine significance of the correlation coefficient and <i>P</i> value less than 0.05 was considered statistically significant.</p