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For the alkaline fuel cell cathode reaction, it is very essential to develop novel catalysts with superior catalytic properties. Here, we report the synthesis of highly active and stable MoS 2 /Pd composites for the oxygen reduction reaction (ORR), via a simple, eco-friendly sonochemical method. The bulk MoS 2 was first transformed into single and few layers MoS 2 nanosheets through ultrasonic exfoliation. Then the exfoliated MoS 2 nanosheets served as supporting materials for the nucleation and further in-situ growth of Pd nanoparticles to form MoS 2 /Pd composites via ultrasonic irradiation. Cyclic voltammetry and rotating disk voltammetry measurements demonstrate that as-prepared MoS 2 /Pd composites which provides a direct four-electron pathway for the ORR, have better electrocatalytic activity, long-term operation stability than commercial Pt/C catalyst. We expect that the present work would provide a promising strategy for the development of efficient oxygen reduction electrocatalyst. In addition, this study can also be extended to the preparation of other hybrid with desirable morphologies and functions. [ABSTRACT FROM AUTHOR]

Porous MnO 2 as a non-noble metal oxygen reduction reaction (ORR) electrocatalyst was prepared by a simple sonochemical route. The as-prepared porous MnO 2 exhibited higher electrocatalytic activity, superior stability and better methanol tolerance than commercial Pt/C catalyst in alkaline media. Furthermore, the ORR proceeded via a nearly four-electron pathway. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) measurements verified that the ORR enhancement was attributed to the porous structure and good dispersity, which facilitated sufficient transport of ions, electrons, O 2 and other reactants in the process of ORR. The results indicated that a facile and feasible sonochemical route could be used to prepare highly active porous MnO 2 electrocatalyst for ORR, which might be promising for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Abstract: Pluronic block copolymers, a kind of non-ionic surfactant, also known as poloxamers, and ultrasound-targeted microbubble destruction have been respectively investigated as vectors for gene delivery in vitro and in vivo. However, they are limited for clinical application due to the relatively low transfer efficiency of each individual vector. In the present study, we explored if the combination of P85, a pluronic block copolymer, Optison, a microbubble contrast agent and ultrasound enhances the transfection of plasmid DNA in vivo using mouse skeletal muscle models. Plasmid encoding green fluorescent protein (GFP) was respectively conjugated with 0.05%P85, 10%Optison, or 0.05%P85 plus 10%Optison, and injected into mouse tibialis anterior (TA) muscles with or without ultrasound irradiation (1MHz, 1W/cm2, 2min and 20% duty cycle). Mice were sacrificed 1week after injection. The TA muscles were collected and cryo-sectioned into a series of 7μm slices. To assess the efficiency of plasmid DNA transfection, tissue sections were counterstained with DAPI and scored by counting the number of GFP-positive fibers. Meanwhile the area of damaged muscles was measured based on the tissues stained with hematoxylin and eosin. Both P85 and Optison significantly enhanced the delivery of plasmid DNA in mouse TA skeletal muscles (P <0.01 and P <0.05 respectively, compared to saline control). In combination with Ultrasound irradiation, P85 (P <0.01, compared to P85 alone) but not Optison (P >0.05, compared to Optison alone) exerted a more pronounced effect on the transfection efficiency. Furthermore P85-induced gene delivery was higher than that by Optison regardless of the presence of ultrasound (P <0.01). The highest transfection efficiency was observed when P85, Optison and ultrasound irradiation were administrated together (P <0.01, compared to any other treatment in this study). The area of damaged muscles was enlarged by ultrasound irradiation in the presence of Optison microbubbles (P <0.01, compared to those groups without ultrasound irradiation). These results suggest that P85, microbubbles and ultrasound irradiation synergistically enhance plasmid DNA delivery in mouse skeletal muscles in vivo. [Copyright &y& Elsevier]

Abstract: Bi2Te3 hexagonal nanoflakes with controllable edge length ranging from ∼150nm to as small as ∼10nm were synthesized via an ultrasonic-assisted disproportionation route, using Te powder and Bi(NO3)3 ·5H2O as raw materials. The mechanochemical effects of the ultrasonic irradiation accelerated the reaction and were helpful to obtain relatively small and uniform nanocrystals. The products were characterized by X-ray powder diffraction, X-ray photoelectron spectra, transmission electron microscopy, and selected area electron diffraction techniques. Electrogenerated chemiluminescence of as-prepared Bi2Te3 was also reported for the first time. [Copyright &y& Elsevier]

Bi(2)Te(3) hexagonal nanoflakes with controllable edge length ranging from approximately 150 nm to as small as approximately 10nm were synthesized via an ultrasonic-assisted disproportionation route, using Te powder and Bi(NO(3))(3).5H(2)O as raw materials. The mechanochemical effects of the ultrasonic irradiation accelerated the reaction and were helpful to obtain relatively small and uniform nanocrystals. The products were characterized by X-ray powder diffraction, X-ray photoelectron spectra, transmission electron microscopy, and selected area electron diffraction techniques. Electrogenerated chemiluminescence of as-prepared Bi(2)Te(3) was also reported for the first time.