High-resolution intravascular magnetic resonance imaging of the coronary artery wall at 3.0 Tesla: toward evaluation of atherosclerotic plaque vulnerability.

BACKGROUND: To validate the feasibility of generating high-resolution intravascular 3.0 Tesla (T) magnetic resonance imaging of the coronary artery wall to further plaque imaging. METHODS: A receive-only 0.014-inch diameter magnetic resonance imaging guidewire (MRIG) was manufactured for intravascular imaging within a phantom experiment and the coronary artery wall of the swine. For coronary artery wall imaging, both high-resolution images and conventional resolution images were acquired. A 16-channel commercial surface coil for magnetic resonance imaging was employed for the control group. RESULTS: For the phantom experiment, the MRIG showed a higher signal-to-noise ratio than the surface coil. The peak signal-to-noise ratio of the MRIG and the surface coil-generated imaging were 213.6 and 19.8, respectively. The signal-to-noise ratio decreased rapidly as the distance from the MRIG increased. For the coronary artery wall experiment, the vessel wall imaging by the MRIG could be identified clearly, whereas the vessel wall imaging by the surface coil was blurred. The average signal-to-noise ratio of the artery wall was 21.1±5.40 by the MRIG compared to 8.4±2.19 by the surface coil, where the resolution was set at 0.2 mm × 0.2 mm × 2 mm. As expected, the high-resolution sequence clearly showed more details than the conventional resolution sequence set at 0.7 mm × 0.7 mm × 2.0 mm. Histological examination showed no evidence of mechanical injuries in the target vessel walls. CONCLUSIONS: The study validated the feasibility of generating magnetic resonance imaging (MRI) at 0.2 mm × 0.2 mm × 2 mm for the coronary artery wall using a 0.014 inch MRIG.

Ag nanoparticles-decorated CoAl-layered double hydroxide flower-like hollow microspheres for enhanced energy storage performance.

Layered double hydroxides (LDHs) have been considered as one class of promising active electrode materials for supercapacitors due to their tunable composition and chemical versatility. Nonetheless, the poor electrical conductivity hinders their further practical applications in supercapacitors. Herein, CoAl LDH flower-like hollow microspheres are decorated with Ag nanoparticles by a facile one-step solvothermal reaction, followed by chemical bath deposition reaction. Experimental results and theoretical calculations indicate that decorating Ag nanoparticles onto CoAl LDH not only reduces the energy band gap and enhances their electrical conductivity, but also promotes fast diffusion kinetics of electrolyte ions and electrochemical reaction activity. Consequently, the prepared Ag/CoAl LDH electrode demonstrates improved specific capacities of 1214 (825) C g-1 at 3 (30) A g-1 and 91% capacity retention over 10,000 cycles at 10 A g-1 compared to the pristine CoAl LDH electrode. Moreover, using Ag/CoAl LDH and N-doped carbon nanotubes as the positive and negative electrodes, respectively, the assembled hybrid capacitor device delivers an energy density of 61.2 Wh kg-1 at a power density of 800 W kg-1. This work may showcase a great promise of engineering conductive nanoparticles-decorated LDHs-based active materials towards high-performance supercapacitors.

Construction of ultra-stable trinickel disulphide (Ni3S2)/polyaniline (PANI) electrodes based on carbon fibers for high performance flexible asymmetric supercapacitors.

Highly flexible supercapacitors (SCs) have attracted significant attention in modern electronics. However, it has been found that flexible, metal sulfide-based electrodes usually suffer from corrosion, instability and low conductivity, which significantly limits their large scale application. Herein, we report on an electrode comprised of highly stable, free-standing carbon fiber/trinickel disulphide covered with polyaniline (CF/Ni3S2@PANI). This electrode was prepared and then employed in a high-performance of flexible asymmetric SCs (FASC). The coating layer of polyaniline served as both a protector and conducting shell for the Ni3S2 due to the nature of the highly stable N-Ni bonds that formed between the polyaniline and Ni3S2. In addition, the lightweight carbon fiber support served as both a current collector and flexible support. The prepared CF/Ni3S2@PANI electrode exhibited a significantly enhanced specific capacity (715.3 F·g-1 at 1 A·g-1) compared with the carbon fiber/Ni3S2 electrode (318 F·g-1 at 1 A·g-1). More importantly, the assembled FASC device delivered an impressive energy density of 35.7 Wh·kg-1 at a power density of 850 W·kg-1. The FASC device benefited from the interconnected flexible microstructure and the stable bond bridges, so that it could be bent into various angles without noticeably impairing its performance. This effective protective strategy may further inspire the design and manufacture of metallic oxide or sulfide electrode with ultrahigh-stability interbond bridges for high-performance flexible supercapacitors.

Ag/MnO2 Nanorod as Electrode Material for High-Performance Electrochemical Supercapacitors.

A one-dimensional hierarchical Ag nanoparticle (AgNP)/MnO2 nanorod (MND) nanocomposite was synthesized by combining a simple solvothermal method and a facile reduction approach in situ. Owing to its high electrical conductivity, the resulting AgNP/MND nanocomposite displayed a high specific capacitance of 314 F g-1 at a current density of 2 A g-1, which was much higher than that of pure MNDs (178 F g-1). Resistances of the electrolyte (Rs) and charge transportation (Rct) of the nanocomposite were much lower than that of pure MNDs. Moreover, the nanocomposite exhibited outstanding long-term cycling ability (9% loss of initial capacity after 1000 cycles). These results indicated that the nanocomposite could serve as a promising and useful electrode material for future energy-storage applications.

Hierarchical assembly of ultrathin hexagonal SnS2 nanosheets onto electrospun TiO2 nanofibers: enhanced photocatalytic activity based on photoinduced interfacial charge transfer.

Well-designed hierarchical nanostructures with one dimensional (1D) TiO(2) nanofibers (120-350 nm in diameter and several micrometers in length) and ultrathin hexagonal SnS(2) nanosheets (40-70 nm in lateral size and 4-8 nm in thickness) were successfully synthesized by combining the electrospinning technique (for TiO(2) nanofibers) and a hydrothermal growth method (for SnS(2) nanosheets). The single-crystalline SnS(2) nanosheets with a 2D layered structure were uniformly grown onto the electrospun TiO(2) nanofibers consisted of either anatase (A) phase or anatase-rutile (AR) mixed phase TiO(2) nanoparticles. The definite heterojunction interface between SnS(2) nanosheets and TiO(2) (A or R) nanoparticles were investigated by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Moreover, the as-prepared SnS(2)/TiO(2) hierarchical nanostructures as nanoheterojunction photocatalysts exhibited excellent UV and visible light photocatalytic activities for the degradation of organic dyes (rhodamine B and methyl orange) and phenols (4-nitrophenol), remarkably superior to the TiO(2) nanofibers and the SnS(2) nanosheets, mainly owing to the photoinduced interfacial charge transfer based on the photosynergistic effect of the SnS(2)/TiO(2) heterojunction. Significantly, the SnS(2)/TiO(2) (AR) hierarchical nanostructures as the tricomponent heterojunction system possessed stronger photocatalytic activity than the bicomponent heterojunction system of SnS(2)/TiO(2) (A) hierarchical nanostructures or TiO(2) (AR) nanofibers, which was discussed in terms of the three-way photosynergistic effect between SnS(2), TiO(2) (A) and TiO(2) (R) component in the SnS(2)/TiO(2) (AR) heterojunction resulting in the high separation efficiency of photoinduced electron-hole pairs, as evidenced by photoluminescence (PL) and surface photovoltage spectra (SPS).

Controllable synthesis of Zn2TiO4@carbon core/shell nanofibers with high photocatalytic performance.

Zn(2)TiO(4)@carbon core/shell nanofibers (Zn(2)TiO(4)@C NFs) with different thickness of carbon layers (from 2 to 8 nm) were fabricated by combining the electrospinning technique and hydrothermal method. The results showed that a uniform carbon layer was formed around the electrospun Zn(2)TiO(4) nanofiber (Zn(2)TiO(4) NFs). By adjusting the hydrothermal fabrication parameters, the thickness of carbon layer varied linearly with the concentration of glucose. Furthermore, the core/shell structure formed between Zn(2)TiO(4) and carbon enhanced the charge separation of pure Zn(2)TiO(4) under ultraviolet excitation, as evidenced by photoluminescence spectra. The photocatalytic studies revealed that the Zn(2)TiO(4)@C NFs exhibited enhanced photocatalytic efficiency of photodegradation of Rhodamine B (RB) compared with the pure Zn(2)TiO(4) NFs under ultraviolet excitation, which might be attributed to the high separation efficiency of photogenerated electrons and holes based on the synergistic effect between carbon and Zn(2)TiO(4). Notably, the Zn(2)TiO(4)@C NFs could be recycled easily by sedimentation without a decrease of the photocatalytic activity.

Iron phthalocyanine/TiO2 nanofiber heterostructures with enhanced visible photocatalytic activity assisted with H2O2.

One-dimensional 2,9,16,23-tetra-nitrophthalocyanine iron(II) (TNFePc)/TiO(2) nanofiber heterostructures have been successfully obtained by a simple combination of electrospinning technique and solvothermal process. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and IR spectrum. The results revealed that the TNFePc nanosheets were successfully grown on the primary TiO(2) nanofibers. And, the coverage density of the secondary TNFePc nanostructures could be controlled by adjusting the experimental parameters. Photocatalytic tests displayed that the H(2)O(2) assisted TNFePc/TiO(2) nanofiber heterostructures (TNFePc/TiO(2)-H(2)O(2)) possessed a much higher degradation rate of methyl orange than the pure TiO(2) and TNFePc/TiO(2) nanofiber without H(2)O(2) under visible light. Moreover, the TNFePc/TiO(2) nanofiber heterostructures could be easily recycled without the decrease of the photocatalytic activity due to their one-dimensional nanostructural property of TiO(2) nanofibers.

Bi2MoO6 ultrathin nanosheets on ZnTiO3 nanofibers: a 3D open hierarchical heterostructures synergistic system with enhanced visible-light-driven photocatalytic activity.

The 3D open Bi(2)MoO(6)/ZnTiO(3) hierarchical heterostructures with Bi(2)MoO(6) ultrathin nanosheets (<10nm) grown on hexagonal-phase ZnTiO(3) nanofibers were fabricated by combining the electrospinning technique and solvothermal method. And, the Bi(2)MoO(6)/ZnTiO(3) hierarchical heterostructures had remarkable light absorption in the visible region. The photocatalytic studies revealed that the hierarchical heterostructures system exhibited exceptional photocatalytic activity in visible-light degradation of Rhodamine B, which might be attributed to the synergistic system with excellent charge separation characteristics and the unique morphology of Bi(2)MoO(6) nanosheets with the extended absorption in the visible light region. What is more, the 3D open structure supported on nanofibrous candidates possessed large surface areas and excellent recyclability.

Enhancement of the visible-light photocatalytic activity of In2O3-TiO2 nanofiber heteroarchitectures.

One-dimensional In(2)O(3)-TiO(2) heteroarchitectures with high visible-light photocatalytic activity have been successfully obtained by a simple combination of electrospinning technique and solvothermal process. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectra. The results revealed that the secondary In(2)O(3) nanostructures were successfully grown on the primary TiO(2) nanofibers substrates. Compared with the pure TiO(2) nanofibers, the obtained In(2)O(3)-TiO(2) heteroarchitectures showed enhancement of the visible-light photocatalytic activity to degrade rhodamine B (RB) because of the formation of heteroarchitectures, which might improve the separation of photogenerated electrons and holes derived from the coupling effect of TiO(2) and In(2)O(3) heteroarchitectures. Moreover, the In(2)O(3)-TiO(2) heteroarchitectures could be easily recycled without the decrease in the photocatalytic activity because of their one-dimensional nanostructural property.

In situ generation of well-dispersed ZnO quantum dots on electrospun silica nanotubes with high photocatalytic activity.

The ZnO quantum dots-SiO(2) nanotubes (ZQDs-SNTs) nanocomposite was successfully fabricated by direct heat treatment of the electrospun zinc acetate/tetraethyl orthosilicate (TEOS)/polymer nanotubes (NTs). The results indicated that the ZnO quantum dots (ZQDs) with diameter about 3-5 nm were highly dispersed on the SiO(2) nanotubes (SNTs). And, there might be Zn-O-Si bonds between ZQDs and SiO(2) matrix, which formed interface states in the ZQDs-SNTs nanocomposite. The photocatalytic studies revealed that the ZQDs-SNTs nanocomposite exhibited high photocatalytic activity to degrade Rhodamine B (RB) under ultraviolet (UV) light irradiation, which might be ascribed to two reasons. The first one was the high dispersity of ZQDs; another one was the high separation efficiency of photogenerated electron-hole pairs due to the trap effect for photogenerated electrons of the interface states between ZQDs and SiO(2). During the photocatalytic reaction, the ZQDs-SNTs nanocomposite also exhibited high chemical stability in a wide range of pH values, which might be ascribed to the protective action of SiO(2) and the presence of Zn-O-Si bonds between ZQDs and SiO(2). Furthermore, the ZQDs-SNTs nanocomposites could be easily recycled because of their one-dimensional nanostructure property.

In situ assembly of well-dispersed Ag nanoparticles (AgNPs) on electrospun carbon nanofibers (CNFs) for catalytic reduction of 4-nitrophenol.

Carbon nanofibers/silver nanoparticles (CNFs/AgNPs) composite nanofibers were fabricated by two steps consisting of the preparation of the CNFs by electrospinning and the hydrothermal growth of the AgNPs on the CNFs. The as-prepared nanofibers were characterized by scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, resonant Raman spectra, thermal gravimetric and differential thermal analysis, and X-ray photoelectron spectroscopy, respectively. The results indicated that not only were AgNPs (25-50 nm) successfully grown on the CNFs but also the AgNPs were distributed without aggregation on the CNFs. Further more, by adjusting the parameters in hydrothermal processing, the content of silver supported on the CNFs could be easily controlled. The catalytic activities of the CNFs/AgNPs composite nanofibers to the reduction of 4-nitrophenol (4-NP) with NaBH(4) were tracked by UV-visible spectroscopy. It was suggested that the CNFs/AgNPs composite nanofibers exhibited high catalytic activity in the reduction of 4-NP, which might be attributed to the high surface areas of AgNPs and synergistic effect on delivery of electrons between CNFs and AgNPs. And, the catalytic efficiency was enhanced with the increasing of the content of silver on the CNFs/AgNPs composite nanofibers. Notably, the CNFs/AgNPs composite nanofibers could be easily recycled due to their one-dimensional nanostructural property.

TiO(2)@carbon core/shell nanofibers: controllable preparation and enhanced visible photocatalytic properties.

TiO(2)@carbon core/shell nanofibers (TiO(2)@C NFs) with different thinkness of carbon layers (from 2 to 8 nm) were fabricated by combining the electrospinning technique and hydrothermal method. The results showed that a uniform graphite carbon layer was formed around the electrospun TiO(2) nanofiber via C-O-Ti bonds. By adjusting the hydrothermal fabrication parameters, the thickness of carbon layer could be easily controlled. Furthermore, the TiO(2)@C NFs had remarkable light absorption in the visible region. The photocatalytic studies revealed that the TiO(2)@C NFs exhibited enhanced photocatalytic efficiency of photodegradation of Rhodamine B (RB) compared with the pure TiO(2) nanofibers under visible light irradiation, which might be attributed to high separation efficiency of photogenerated electrons and holes based on the synergistic effect between carbon as a sensitizer and TiO(2) with one dimension structure. Notably, the TiO(2)@C NFs could be easily recycled due to their one-dimensional nanostructural property.

Highly efficient decomposition of organic dye by aqueous-solid phase transfer and in situ photocatalysis using hierarchical copper phthalocyanine hollow spheres.

The hierarchical tetranitro copper phthalocyanine (TNCuPc) hollow spheres were fabricated by a simple solvothermal method. The formation mechanism was proposed based on the evolution of morphology as a function of solvothermal time, which involved the initial formation of nanoparticles followed by their self-aggregation to microspheres and transformation into hierarchical hollow spheres by Ostwald ripening. Furthermore, the hierarchical TNCuPc hollow spheres exhibited high adsorption capacity and excellent simultaneously visible-light-driven photocatalytic performance for Rhodamine B (RB) under visible light. A possible mechanism for the "aqueous-solid phase transfer and in situ photocatalysis" was suggested. Repetitive tests showed that the hierarchical TNCuPc hollow spheres maintained high catalytic activity over several cycles, and it had a better regeneration capability under mild conditions.

Tin oxide (SnO2) nanoparticles/electrospun carbon nanofibers (CNFs) heterostructures: controlled fabrication and high capacitive behavior.

Tin oxide (SnO(2))/carbon nanofibers (CNFs) heterostructures were fabricated by combining the versatility of the electrospinning technique and template-free solvent-thermal process. The results revealed that the SnO(2) nanostructures were successfully grown on the primary electrospun carbon nanofibers substrates. And, the coverage density of SnO(2) nanoparticles coating on the surface of the CNFs could be controlled by simply adjusting the mass ratio of CNFs to SnCl(4)·5H(2)O in the precursor during the solvent-thermal process for the fabrication of SnO(2)/CNFs heterostructures. The electrochemical performances of the SnO(2)/CNFs heterostructures as the electrode materials for supercapacitors were evaluated by cyclic voltammetry (CV) and galvanostatic charge-discharge measurement in 1 M H(2)SO(4) solution. At different scan rates, all the samples with different coverage densities of SnO(2) showed excellent capacitance behavior. And, the sample CS2 (the mass ratio of CNFs to SnCl(4)·5H(2)O reached 1:7) exhibited a maximum specific capacitance of 187 F/g at a scan rate of 20 mV/s. Moreover, after 1000 cycles, the specific capacitance retention of this sample was over 95%. The high capacitive behavior could be ascribed to the low resistance of SnO(2)/CNFs heterostructures and rapid transport of the electrolyte ions from bulk solution to the surface of SnO(2).

In situ assembly of well-dispersed gold nanoparticles on electrospun silica nanotubes for catalytic reduction of 4-nitrophenol.

The tubular nanocomposite with well-dispersed distribution of small gold nanoparticles (AuNPs) assembled on the inside and outside surfaces of silica nanotubes (SNTs) was fabricated by combining the single capillary electrospinning technique and an in situ reduction approach. The AuNPs/SNTs nanocomposite exhibited a good catalytic activity for reduction of 4-nitrophenol (4-NP).

High photocatalytic activity of ZnO-carbon nanofiber heteroarchitectures.

One-dimensional ZnO-carbon nanofibers (CNFs) heteroarchitectures with high photocatalytic activity have been successfully obtained by a simple combination of electrospinning technique and hydrothermal process. The as-obtained products were characterized by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and IR spectrum. The results revealed that the secondary ZnO nanostructures were successfully grown on the primary CNFs substrates without aggregation. And, the coverage density of ZnO nanoparticles coating on the surface of the CNFs could be controlled by simply adjusting the mass ratio of zinc acetate to CNFs in the precursor during the hydrothermal process for the fabrication of ZnO-CNFs heterostructures. The obtained ZnO-CNFs heteroarchitectures showed high photocatalytic property to degrade rhodamine B (RB) because of the formation of heteroarchitectures, which might improve the separation of photogenerated electrons and holes. Moreover, the ZnO-CNFs heteroarchitectures could be easily recycled without the decrease in photocatalytic activity due to their one-dimensional nanostructural property.

Hierarchical nanostructures of copper(II) phthalocyanine on electrospun TiO(2) nanofibers: controllable solvothermal-fabrication and enhanced visible photocatalytic properties.

In the present work, 2,9,16,23-tetranitrophthalocyanine copper(II) (TNCuPc)/TiO(2) hierarchical nanostructures were successfully fabricated by a simple combination method of electrospinning technique and solvothermal processing. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), UV-vis diffuse reflectance (DR), Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric and differential thermal analysis (TG-DTA) were used to characterize the as-synthesized TNCuPc/TiO(2) hierarchical nanostructures. The results showed that the secondary TNCuPc nanostructures were not only successfully grown on the primary TiO(2) nanofibers substrates but also uniformly distributed without aggregation. By adjusting the solvothermal fabrication parameters, the TNCuPc nanowires or nanoflowers were facilely fabricated, and also the loading amounts of TNCuPc could be controlled on the TNCuPc/TiO(2) hierarchical nanostructural nanofibers. And, there might exist the interaction between TNCuPc and TiO(2). A possible mechanism for the formation of TNCuPc/TiO(2) hierarchical nanostructures was suggested. The photocatalytic studies revealed that the TNCuPc/TiO(2) hierarchical nanostructures exhibited enhanced photocatalytic efficiency of photodegradation of Rhodamine B (RB) compared with the pure TNCuPc or TiO(2) nanofibers under visible-light irradiation.

Zinc phthalocyanine hierarchical nanostructure with hollow interior space: solvent-thermal synthesis and high visible photocatalytic property.

A novel zinc phthalocyanine (ZnPc) hierarchical nanostructure with hollow interior space has been successfully obtained by a facile ethylene glycol solvent-thermal synthetic route. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), IR spectrum, UV-vis spectrum, Brunauer-Emmett-Teller analysis and contact angle measurement. It was indicated that the ZnPc micro-rectangular tubes with hollow interior space were built from densely nanosheets with a thickness of about 20 nm. The obtained ZnPc showed high visible photocatalytic property to degrade rhodamine B (RB), which could be ascribed to the contribution of hierarchical nanostructure, high crystallinity and super-hydrophobic property.