32 research outputs found
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) Fe<sup>0</sup> systems. The rates of TCE reduction were
unaffected by ionic strength over the range of 0.1–10 mM NaCl,
increased with Ca<sup>2+</sup> or Mg<sup>2+</sup> 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 Ca<sup>2+</sup>/Mg<sup>2+</sup>,
presumably due to decreased adsorption of humic acid onto nFe/FeS
surface by the formation of humic acid–Ca<sup>2+</sup>/Mg<sup>2+</sup> 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 (Pd<sup>2+</sup>, Cu<sup>2+</sup>, Ni<sup>2+</sup>, Co<sup>2+</sup>, and Mn<sup>2+</sup>) 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 Mn<sup>2+</sup> and Cu<sup>2+</sup> decreased TCE reduction rates,
while Pd<sup>2+</sup>, Co<sup>2+</sup>, and Ni<sup>2+</sup> 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><sub>obs</sub>) 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><sub>obs</sub> was best
described by the exchange current density for activation of hydrogen,
whereas <i>k</i><sub>obs</sub> 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 polyÂ(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 AgBiO<sub>3</sub> for the Oxidative Remediation of Organic Pollutants
In
this study, we synthesized a novel perovskite nanomaterial consisting
of AgBiO<sub>3</sub> nanoparticles (NPs) via an ion-exchange method
for remediation of polluted environments. The AgBiO<sub>3</sub> 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
AgBiO<sub>3</sub>, resulting in the formation of ROS somehow. The
self-produced <sup>1</sup>O<sub>2</sub>, O<sub>2</sub><sup>•–</sup>, and <sup>•</sup>OH were confirmed by electron spin resonance
spectroscopy using a spin trap technique. We found that the AgBiO<sub>3</sub> 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, AgBiO<sub>3</sub> NPs still achieved
79% of degradation after 30 min of treatment. Characterization results
revealved that the lattice oxygen inside AgBiO<sub>3</sub> 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
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
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
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