58 research outputs found
Binary System for MicroRNA-Targeted Imaging in Single Cells and Photothermal Cancer Therapy
Abnormal expression of microRNAs
(miRNAs) is often associated with
tumorigenesis, metastasis, and progression. Among them, miRNA-21 is
found to be overexpressed in most of the cancer cells. Here, a binary
system is designed for miRNA-21 targeted imaging and photothermal
treatment in single cells. The binary system is composed by a pair
of probes (probe-1 and probe-2), which are encapsulated in liposomes
for cell delivery. Both of the two probes adopt gold nanoparticles
(AuNPs) as the core material, and the AuNPs are functionalized with
Cy5-marked molecular beacon (MB-1/MB-2 for probe-1/probe-2, respectively).
The loop part of MBs are designed to be complementary with miRNA-21.
Therefore, after the binary system enters into the cytoplasm, MBs
can be opened upon miRNA-21 triggered hybridization, which turns âonâ
the fluorescence of Cy5 for the localization of miRNA-21. At the same
time, a cross-linking between the probes occurs since the far ends
of MB-1 and MB-2 are designed to be complementary with each other.
The miRNA-induced aggregation shifts the absorption of AuNPs to near-infrared,
which can be observed under dark-field microscopy (DFM) and used for
the following photothermal therapy. Under near-infrared (NIR) irradiation,
MCF-7 breast cancer cells are successfully killed. The proposed system
can be further applied in tumor-bearing mice and shows significant
therapeutic effect. This work provides a new tool for intracellular
miRNA analysis and targeted treatment against cancer
Simultaneous NO Removal and Hg<sup>0</sup> Oxidation over CuO Doped V<sub>2</sub>O<sub>5</sub>âWO<sub>3</sub>/TiO<sub>2</sub> Catalysts in Simulated Coal-Fired Flue Gas
A series
of CuO doped V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2</sub> based commercial selective catalytic reduction (SCR)
catalysts were synthesized via the improved impregnation method for
simultaneous NO removal and Hg<sup>0</sup> oxidation under simulated
coal-fired flue gas at a temperature range of 150â400 °C.
Several characterization techniques, including BrunauerâEmmettâTeller
analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy
(XPS), and temperature-programmed reduction of H<sub>2</sub> (H<sub>2</sub>-TPR), were used to characterize the catalysts. The results
indicated that Cu<sub>3</sub>-SCR catalyst exhibited the superior
catalytic activity and a wide active temperature window for simultaneous
NO removal and Hg<sup>0</sup> oxidation. The effects of flue gas components
on the catalytic activity were also investigated. The results indicated
that Cu<sub>3</sub>-SCR catalyst showed good performances on SO<sub>2</sub> tolerance and H<sub>2</sub>O resistance. The effect of Hg<sup>0</sup> on NO removal was almost negligible. However, the copresence
of NO and NH<sub>3</sub> obviously inhibited the Hg<sup>0</sup> oxidation
activity. Further study revealed that this inhibiting effect was weakened
as the consumption of NH<sub>3</sub>. The BET and XRD results suggested
that the highly dispersed Cu species was beneficial to the superior
catalytic activity of the Cu<sub>3</sub>-SCR catalyst. The XPS and
H<sub>2</sub>-TPR analyses indicated that the Cu<sub>3</sub>-SCR catalyst
possessed abundant chemisorbed oxygen and good redox ability, which
was ascribed to the strong synergy between CuO and V<sub>2</sub>O<sub>5</sub> on the catalyst. The redox cycle of V<sup>4+</sup> + Cu<sup>2+</sup> â V<sup>5+</sup> + Cu<sup>+</sup> in Cu<sub>3</sub>-SCR catalyst significantly improved the catalytic activity for simultaneous
NO removal and Hg<sup>0</sup> oxidation. The mechanism of Hg<sup>0</sup> oxidation over the Cu<sub>3</sub>-SCR catalyst was also investigated
Growth of SiC Whiskers onto Carbonizing Coir Fibers by Using Silicon Slurry Waste
To
reduce environmental pollution and waste of resources, it is
very important to recycle valuable materials in silicon slurry waste
(SSW). We report a novel method for the rapid preparation of SiC nanowhiskers
by spark plasma (SP) assisted thermal treatment using SSW as the silicon
source. In the preparation process, coir fibers were used as the carbon
source and whisker growth substrate. At 1100â1300 °C,
carbon-rich tadpole-like 3CâSiC whiskers with Fe catalyst caps
were prepared by the vaporâliquidâsolid growth mechanism.
At 1400â1600 °C, carbon-rich, stick-like 3CâSiC
whiskers without Fe catalyst caps with aspect ratios of about 40,
and diameters of about 50 nm were prepared by the vaporâsolid
growth mechanism. The SiC whiskers grew along the [111] direction
on the (111) plane at different temperatures. At the optimum temperature
of 1500 °C, the silicon in SSW reacted completely, and SiC whiskers
with good morphology were prepared. Furthermore, the photoluminescence
(PL) spectra of SiC whiskers showed strong blue-violet emission at
450 nm. Accordingly, this study provides an environmentally friendly
method for preparing SiC whiskers
Preparation and Characterization of Perfluorosulfonic Acid Nanofiber Membranes for Pervaporation-Assisted Esterification
Multilayer membranes were prepared
by the combination of perfluorosulfonic
acid/SiO<sub>2</sub> nanofibers and a polyÂ(vinyl alcohol) (PVA) pervaporation
layer and were used to enhance the esterification of acetic acid (HAc)
and ethanol (EtOH). The esterificationâpervaporation experiments
were carried out in a continuous membrane contactor. The effects of
the temperature, the ratio of HAc to EtOH, and the ratio of membrane
area to reaction volume were investigated. The results demonstrated
that the membranes had good catalytic activities even at low temperature
because of the nanofibrous structure of the catalysis layer. The conversion
of HAc at 60 °C after 10 h was 10â15% more than the equilibrium
conversion and by improved about 45% with respect to the equilibrium
conversion after 55 h. The yield of EtAc was higher than 90%, which
demonstrates that the difunctional membrane could enhance the esterification
process greatly through the in situ removal of water
Facile Synthesis of Surface-Modified Nanosized 뱉Fe<sub>2</sub>O<sub>3</sub> as Efficient Visible Photocatalysts and Mechanism Insight
In this study, α-Fe<sub>2</sub>O<sub>3</sub> nanoparticles
with high visible photocatalytic activity for degrading liquid-phase
phenol and gas-phase acetaldehyde have been controllably synthesized
by a simple one-pot water-organic two-phase separated hydrolysis-solvothermal
(HST) method. Further, the visible photocatalytic activity is enhanced
greatly after modification with a proper amount of phosphate. The
enhanced activity is attributed to the increased charge separation
by promoting photogenerated electrons captured by the adsorbed O<sub>2</sub> by means of the atmosphere-controlled surface photovoltage
spectra, along with the photoelectrochemical IâV curves. On
the basis of the O<sub>2</sub> temperature-programmed desorption measurements,
it is suggested for the first time that the promotion effect results
from the increase in the amount of O<sub>2</sub> adsorbed on the surfaces
of Fe<sub>2</sub>O<sub>3</sub> by the partial substitution of âFeâOH
with âFeâOâPâOH surface ends. Expectedly,
the positive strategy would be also applicable to other visible-response
nanosized oxides as efficient photocatalysts. This work will provide
us with a feasible route to synthesize oxide-based nanomaterials with
good photocatalytic performance
Multivariate analyses assessing the effects of only-child on sex-related acknowledge, attitude and behavior.
a<p>Standardized regression coefficient and odds ratio with 95% confidence interval in parentheses was adjusted for age, major, grade, nationality, hometown area, and family economic status.</p>b<p>p<0.05 <sup>c</sup>p<0.01.</p
Risky sexual behaviors and risks among sexually active female students who were only-child and students with siblings.
a<p>Missed cases were excluded.</p>b<p>Significance tests was chi-squared tests for dichotomous variables.</p
Systematic Investigation of Isoindigo-Based Polymeric Field-Effect Transistors: Design Strategy and Impact of Polymer Symmetry and Backbone Curvature
Ten isoindigo-based polymers were synthesized, and their
photophysical
and electrochemical properties and device performances were systematically
investigated. The HOMO levels of the polymers were tuned by introducing
different donor units, yet all polymers exhibited <i>p</i>-type semiconducting properties. The hole mobilities of these polymers
with centrosymmetric donor units exceeded 0.3 cm<sup>2</sup> V<sup>â1</sup> s<sup>â1</sup>, and the maximum reached 1.06
cm<sup>2</sup> V<sup>â1</sup> s<sup>â1</sup>. Because
of their low-lying HOMO levels, these copolymers also showed good
stability upon moisture. AFM and GIXD analyses revealed that polymers
with different symmetry and backbone curvature were distinct in lamellar
packing and crystallinity. DFT calculations were employed to help
us propose the possible packing model. Based on these results, we
propose a design strategy, called âmolecular dockingâ,
to understand the interpolymer ÏâÏ stacking. We
also found that polymer symmetry and backbone curvature affect interchain âmolecular
dockingâ of isoindigo-based polymers in film, ultimately leading
to different device performance. Finally, our design strategy maybe
applicable to other reported systems, thus representing a new concept
to design conjugated polymers for field-effect transistors
Synthesis and Performances of UV-Curable PolysiloxaneâPolyether Block Polyurethane Acrylates for PVC Leather Finishing Agents
A series
of multifunctional UV-curable polysiloxaneâpolyether block
polyurethane acrylates prepolymers (TSi<sup>1</sup>E<sup>9</sup>PUA,
TSi<sup>3</sup>E<sup>7</sup>PUA, TSi<sup>5</sup>E<sup>5</sup>PUA,
TSi<sup>7</sup>E<sup>3</sup>PUA, and TSi<sup>9</sup>E<sup>1</sup>PUA)
used for polyvinyl chloride (PVC) leather finishing agents have been
prepared and characterized by nuclear magnetic resonance (NMR), Fourier
transform infrared (FTIR), and gel permeation chromatography (GPC).
All five multifunctional prepolymers exhibited excellent photopolymerization
efficiency and good yellowing resistance. And the content of polysiloxane
in prepolymers obviously affected the viscosity, thermal stability,
tensile strength, elongation at break, and surface hydrophobicity
of the photopolymerization systems. The system with the prepolymer
containing more polysiloxane segments presented a high viscosity,
and UV-cured film had relatively good thermal stability, elongation
at break, and surface hydrophobicity accordingly. The properties of
the prepolymers well satisfied the application requirements for leather
finishing agents. Furthermore, surface microstructures of UV-cured
films were characterized by scanning electron microscopy (SEM) and
energy dispersive spectrometer (EDS). More importantly, the PVC leather
finishing agents designed based on the multifunctional polysiloxaneâpolyether
block polyurethane acrylates possessed excellent comprehensive performances
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