139 research outputs found
Ion-Imprinted Mesoporous Silica for Selective Removal of Uranium from Highly Acidic and Radioactive Effluent
It is strategically
important to recycle uranium from radioactive liquid wastes for future
uranium supply of nuclear energy. However, it is still a challenge
to adsorb uranium selectively from highly acidic and radioactive waste.
In this paper, we report a novel strategy for effective uranium removal
from highly acidic and radioactive media by surface ion-imprinted
mesoporous silica sorbent. The sorbent was successfully synthesized
by a co-condensation method with uranyl as the template ion and diethylphosphatoethyltriethoxysilane
as the functional ligands. The pseudo-second-order model and Langmuir
model showed better correlation with the sorption kinetic and isotherm
data, and the sorption equilibrium could be reached within 40 min,
the maximum adsorption capacity from Langmuir model was 80 mg/g in
1 mol/L nitric acid (HNO<sub>3</sub>) solution at 298.15 K. The sorbent
showed faster kinetics and higher selectivity toward uranium over
other ions compared with nonimprinted mesoporous and other previous
sorbents. Furthermore, the ion-imprinted materials exhibited remarkable
radioresistance stability and could be regenerated efficiently after
five cycles. This work may provide a new approach for highly efficient
sorption of uranium from strong HNO<sub>3</sub> and radioactive media
Surface Ion-Imprinted Polypropylene Nonwoven Fabric for Potential Uranium Seawater Extraction with High Selectivity over Vanadium
Uranium seawater
extraction is strategically important to guarantee
the future supply for nuclear power generation. However, it is still
a challenge to selectively capture uranium over vanadium in seawater.
In this paper, we propose a new method for potential uranium seawater
extraction with high selectivity over vanadium. Specifically, surface
ion-imprinted polypropylene nonwoven fabric is prepared by copolymerization
of 4-vinylbenzyl chloride and 1-vinylimidazole in the presence of
uranyl tricarbonate complex. The sorption follows the pseudo-second-order
model and can reach the equilibrium with a large capacity of 133.3
mg/g within 15 h at pH 8.0 and 298.15 K. The imprinted fabric shows
excellent selectivity toward uranium over vanadium and the other coexisting
ions in seawater. In addition, it exhibits good salt-resistant stability
and can be regenerated efficiently after five cycles. This work indicates
that the imprinted fabric may be a promising sorbent for potential
uranium seawater extraction
Optical Extinction Properties of Perforated Gold-Silica-Gold Multilayer Nanoshells
Symmetry breaking in gold nanoshell (or multilayer nanoshells)
can supply many interesting optical properties, which has been studied
in gold nanostrucutres such as nanocup, nanoegg, and core offset gold-silica-gold
multilayer nanoshells. In this work, the optical extinction properties
of the perforated gold-silica-gold multilayer nanoshells are studied
by the discrete dipole approximation method simulations and plasmon
hybridization theory. The extinction spectra of these particles are
sensitive to the orientation of the particle with respect to polarization
of the light due to the symmetry breaking. Because of the coupling
of the plasmon resonance modes between the inner gold sphere and the
outer nanocup structure, the perforated gold-silica-gold nanoshell
provides the additional plasmon resonance peak and an even greater
spectral tunability comparing with the nanocup of similar dimensions.
By changing the geometry of the particles, the extinction peaks of
the particles can be easily tuned into the near-infrared region, which
is favorable for biological applications. The local refractive index
sensitivity of the particles is also investigated, and the multiple
extinction peaks simultaneous shift is found as surrounding medium
is altered. The perforated gold-silica-gold multilayer nanoshells
may provide various applications ranging from angularly selective
filters to biological sensors
Highlights;Prime Novelty Statement from Novel ternary nanocomposites of MWCNTs/PANI/MoS<sub>2</sub>: preparation, characterization and enhanced electrochemical capacitance
1. Nanoflower-like MoS2 grown on the surface of MWCNTs/PANI nano-stem is successfully synthesized. 2. The obtained ternary hybrid exhibits a high capacitance of 542.56 F g-1 at 0.5 A g-1 and excellent cycling stability (73.7% capacitance retention) over 3000 cycles. 3. This work offers a potential electrode material for supercapacitors. ;In this work, a novel hierarchical structure, nanoflower-like MoS2 grown on the surface of MWCNTs/PANI nano-stem, is synthesized sucessfully. The obtained ternary nanocomposite exhibits excellent electrochemical performance, which can be used as the electrode material of supercapacitor
Biologically Inspired Polydopamine Capped Gold Nanorods for Drug Delivery and Light-Mediated Cancer Therapy
Multifunctional drug delivery and
combined multimodal therapy strategies are very promising in tumor
theranostic applications. In this work, a simple and versatile nanoplatform
based on biologically inspired polydopamine capped gold nanorods (GNR-PDA)
is developed. Dopamine, a well-known neurotransmitter associated with
many neuronal disorders, can undergo self-polymerization on the surface
of GNRs to form a stable PDA shell. Its unique molecular adsorption
property, as well as its high chemical stability and biocompatibility,
facilitate GNR-PDA as an ideal candidate for drug delivery. Methylene
blue (MB) and doxorubicin (DOX) are directly adsorbed on GNR-PDA via
electrostatic and/or π–π stacking interactions,
forming GNR-PDA-MB and GNR-PDA-DOX nanocomposites, respectively. The
GNR-PDA-MB can generate reactive oxygen species (ROS, from MB) or
hyperthermia (from GNR-PDA) with high efficiency under deep-red/NIR
laser irradiation, while the GNR-PDA-DOX exhibits light-enhanced drug
release under NIR laser irradiation. The combined dual-modal light-mediated
therapy, by using GNR-PDA-MB [photodynamic/photothermal therapy (PDT/PTT)]
and GNR-PDA-DOX (Chemo/PTT), is carried out and shows remarkable cancer
cell killing efficiency in vitro and significant suppression of tumor
growth in vivo, which are much more distinct than any single-modal
therapy strategy. Our work illustrates that GNR-PDA could be a promising
nanoplatform for multifunctional drug delivery and multimodal tumor
theranostics in the future
The effect of renal denervation on resistant hypertension: Meta-analysis of randomized controlled clinical trials
<p><i>Background</i>: This meta-analysis was conducted to evaluate the efficiency of renal denervation (RDN) on resistant hypertension. <i>Methods</i>: PubMed, EMBASE, and the Cochrane Central database were searched for eligible randomized controlled clinical trials (RCTs). Changes from the baseline of the office blood pressure and the 24-h ambulatory blood pressure were extracted. <i>Results</i>: Nine RCTs were included. RDN reduced the mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) by −8.23 mm Hg (95%CI: −16.86, 0.39) and −3.77 mm Hg (95%CI: −7.21, −0.32), respectively, compared with the control. In the population with a baseline SBP more than 170 mm Hg, the RDN reduced SBP by −17.77 mm Hg (95%CI: −33.73, −1.82) and DBP by −7.51 mm Hg (95%CI: −12.58, −2.44). In the subgroup with no medication adjustment, the RDN reduced SBP by −15.56 mm Hg (95%CI: −26.33, −4.80) and DBP by −6.89 mm Hg (95%CI: −9.99, −3.79). The proportion of patients with SBP decrease of 10 mm Hg or more and the controlled office BP were not different between two groups. RDN reduced 24-h mean SBP and DBP by −3.34 mm Hg (95%CI: −5.30, −1.38) and −1.56 mm Hg (95%CI: −2.71, −0.41), respectively. The SBPs in the subgroups with higher baseline SBP and with no medication adjustment were significantly decreased after the HTN-3 was omitted. <i>Conclusion</i>: Radiofrequency RDN in a randomized manner did not have superiority compared with medical treatment at 6-month follow-up in general population. Current evidence provides insufficient evidence to support the use of such RDN strategy in the treatment of resistant hypertension. The result could not be used to extrapolate other strategies’ effect.</p
Solvent-Induced Assembly of Octacyanometalates-Based Coordination Polymers with Unique <i>afm</i>1 Topology and Magnetic Properties
Aqueous solution was introduced into
the self-assembly of water-insoluble
(Bu<sub>3</sub>NH)<sub>3</sub>[MÂ(CN)<sub>8</sub>] (M = W, Mo) and
MnÂ(NO<sub>3</sub>)<sub>2</sub>·6H<sub>2</sub>O to afford two,
three-dimensional (3D) coordination polymers (CPs), {[μ<sub>8</sub>-M<sup>V</sup>(CN)<sub>8</sub>Mn<sup>II</sup><sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>(CH<sub>3</sub>OH)]Â[NO<sub>3</sub>]}<sub><i>n</i></sub> (M = W <b>1</b>, Mo <b>2</b>), while
polymer {[μ<sub>4</sub>-W<sup>V</sup>(CN)<sub>8</sub>Mn<sup>II</sup><sub>2</sub>(DMF)<sub>8</sub>]Â(ClO<sub>4</sub>)}<sub><i>n</i></sub> (DMF = <i>N</i>,<i>N</i>-dimethylformamide)
(<b>3</b>) was crystallized from the reaction of (Bu<sub>3</sub>NH)<sub>3</sub>[WÂ(CN)<sub>8</sub>] and MnÂ(ClO<sub>4</sub>)<sub>2</sub>·6H<sub>2</sub>O in DMF. All three CPs <b>1</b>, <b>2</b>, and <b>3</b> have been well-characterized by elemental
analysis, infrared spectra, single-crystal X-ray diffraction, as well
as thermogravimetric analysis. The single-crystal X-ray structural
analysis shows that both CPs <b>1</b> and <b>2</b> crystallize
in the monoclinic crystal system with space group of <i>C</i>2/<i>c</i> and possess the infinite 3D framework in an
unprecedented <i>afm</i>1 topology geometry, which is an
unreported 4-nodal 4,4,8,8-coordinated net with point symbol {4<sup>11</sup>.6<sup>12</sup>.8<sup>5</sup>}Â{4<sup>17</sup>.6<sup>10</sup>.8}Â{4<sup>5</sup>.6}<sub>4</sub>. Polymer <b>3</b> crystallizes
in the space group of <i>P</i>4<sub>2</sub>/<i>m</i> as a 3D supermolecule structure, which is constructed by one-dimensional
(1D) cationic {[μ<sub>4</sub>-W<sup>V</sup>(CN)<sub>8</sub>Mn<sup>II</sup><sub>2</sub>(DMF)<sub>8</sub>]<sup>+</sup>}<sub><i>n</i></sub> chains linked via the hydrogen bonds. Magnetic susceptibility
measurements in the temperature range of 2–300 K reveal that
CPs <b>1</b> and <b>2</b> exhibit the similar typical
antiferromagnetic properties, while CP <b>3</b> shows the ferromagnetic
property
A Three-Dimensional Hetero-Bimetallic Coordination Polymer with Unusual (4,5)-Connected Topology and Ferrimagnetic Property Based on Octacyanotungstate and Polydentate Ligand
A three-dimensional (3D) manganese–tungsten
bimetallic coordination
polymer (CP) {{[μ<sub>5</sub>-WÂ(CN)<sub>8</sub>]<sub>2</sub>Â[MnÂ(HMTA)<sub>1.5</sub>]<sub>2</sub>Â[MnÂ(HMTA)Â(H<sub>2</sub>O)<sub>2</sub>]}·2H<sub>2</sub>O}<sub><i>n</i></sub> (CP-<b>1</b>) (HMTA = hexamethylenetetramine) is constructed
by the reaction of the molecular building block [WÂ(CN)<sub>8</sub>]<sup>3–</sup> and tetradentate bridging ligand HMTA with
d<sup>5</sup> transition metal ion Mn<sup>2+</sup>. CP-<b>1</b> has been unambiguously confirmed by Fourier-transform infrared spectroscopy,
elemental analysis, thermogravimetric analysis, and single-crystal
and powder X-ray diffraction. Crystallographic analysis reveals that,
crystallizing in the monoclinic crystal system with <i>P</i>2<sub>1</sub>/<i>c</i> space group, CP-<b>1</b> possesses
an infinite 3D framework and exhibits an unusual (4,5)-connected <b>4,5T7</b> topology with point symbol (3<sup>2</sup>·6<sup>2</sup>·7<sup>2</sup>)Â(3·4<sup>4</sup>·5<sup>2</sup>·6<sup>2</sup>·7)<sub>4</sub>. The extended 3D structure
is constructed by two-dimensional (2D) cyano-bridged corrugated -W–Mn2–W–Mn2-
layers pillared via the [Mn1Â(HMTA)Â(H<sub>2</sub>O)<sub>2</sub>] units.
The magnetic investigation indicates ferrimagnetic behavior for CP-<b>1</b> because of the antiferromagnetic coupling between W<sup>V</sup> (<i>S</i> = 1/2) and Mn<sup>II</sup> (<i>S</i> = 5/2) centers mediated by cyano bridges
Solvent-Induced Assembly of Octacyanometalates-Based Coordination Polymers with Unique <i>afm</i>1 Topology and Magnetic Properties
Aqueous solution was introduced into
the self-assembly of water-insoluble
(Bu<sub>3</sub>NH)<sub>3</sub>[MÂ(CN)<sub>8</sub>] (M = W, Mo) and
MnÂ(NO<sub>3</sub>)<sub>2</sub>·6H<sub>2</sub>O to afford two,
three-dimensional (3D) coordination polymers (CPs), {[μ<sub>8</sub>-M<sup>V</sup>(CN)<sub>8</sub>Mn<sup>II</sup><sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>(CH<sub>3</sub>OH)]Â[NO<sub>3</sub>]}<sub><i>n</i></sub> (M = W <b>1</b>, Mo <b>2</b>), while
polymer {[μ<sub>4</sub>-W<sup>V</sup>(CN)<sub>8</sub>Mn<sup>II</sup><sub>2</sub>(DMF)<sub>8</sub>]Â(ClO<sub>4</sub>)}<sub><i>n</i></sub> (DMF = <i>N</i>,<i>N</i>-dimethylformamide)
(<b>3</b>) was crystallized from the reaction of (Bu<sub>3</sub>NH)<sub>3</sub>[WÂ(CN)<sub>8</sub>] and MnÂ(ClO<sub>4</sub>)<sub>2</sub>·6H<sub>2</sub>O in DMF. All three CPs <b>1</b>, <b>2</b>, and <b>3</b> have been well-characterized by elemental
analysis, infrared spectra, single-crystal X-ray diffraction, as well
as thermogravimetric analysis. The single-crystal X-ray structural
analysis shows that both CPs <b>1</b> and <b>2</b> crystallize
in the monoclinic crystal system with space group of <i>C</i>2/<i>c</i> and possess the infinite 3D framework in an
unprecedented <i>afm</i>1 topology geometry, which is an
unreported 4-nodal 4,4,8,8-coordinated net with point symbol {4<sup>11</sup>.6<sup>12</sup>.8<sup>5</sup>}Â{4<sup>17</sup>.6<sup>10</sup>.8}Â{4<sup>5</sup>.6}<sub>4</sub>. Polymer <b>3</b> crystallizes
in the space group of <i>P</i>4<sub>2</sub>/<i>m</i> as a 3D supermolecule structure, which is constructed by one-dimensional
(1D) cationic {[μ<sub>4</sub>-W<sup>V</sup>(CN)<sub>8</sub>Mn<sup>II</sup><sub>2</sub>(DMF)<sub>8</sub>]<sup>+</sup>}<sub><i>n</i></sub> chains linked via the hydrogen bonds. Magnetic susceptibility
measurements in the temperature range of 2–300 K reveal that
CPs <b>1</b> and <b>2</b> exhibit the similar typical
antiferromagnetic properties, while CP <b>3</b> shows the ferromagnetic
property
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