Search

The influence of nano-copper (n-Cu), nano-nickel (n-Ni) and carbon nanotubes on the combustion performance of RDX-CMDB propellants was investigated. The mechanism of n-Ni on the combustion performance was also discussed by analysis of flame morphology and thermal decomposition performance. The results reveal that n-Ni with mass ratio of 0. 6% would reduce the pressure exponent of RDX-CMDB propellant from 0.29 to 0.11 in the pressure range of 6 -- 16MPa. By contrast, the effect was not obvious for the 0.2% n-Cu, which even causes the decrease of burning rate at 2 MPa and 8-16 MPa. For the 0. 8% CNTs with conventional Pb-Cu-C as catalyst, the burning rate of RDX-CMDB propellant increases from 17.12 to 22.12mm/s at 10MPa. Furthermore, The thermal decomposition and flame morphology imply that n-Ni improves the decomposition heat, enhances the burning surface temperature and thermal feedback, which is contributed to the thermal decomposition rate. [ABSTRACT FROM AUTHOR]

This study explored the novel use of iron oxide (IO) nanoparticles (<20 nm) as a vaccine delivery platform without additional adjuvants. A recombinant malaria vaccine antigen, the merozoite surface protein 1 (rMSP1), was conjugated to IO nanoparticles (rMSP1-IO). Immunizations in outbred mice with rMSP1-IO achieved 100% responsiveness with antibody titers comparable to those obtained with rMSP1 formulated with a clinically acceptable adjuvant, Montanide ISA51 (2.7×10-3 vs. 1.6×10-3; respectively). Only rMSP1- O could induce significant levels (80%) of parasite inhibitory antibodies. The rMSP1-IO was highly stable at 4°C and was amenable to lyophilization, maintaining its antigenicity, immunogenicity, and ability to induce inhibitory antibodies. Further testing in nonhuman primates, Aotus monkeys, also elicited 100% immune responsiveness and high levels of parasite inhibitory antibodies (55-100% inhibition). No apparent local or systemic toxicity was associated with IO immunizations. Murine macrophages and dendritic cells efficiently (>90%) internalized IO nanoparticles, but only the latter were significantly activated, with elevated expression/ secretion of CD86, cytokines (IL-6, TNF-α, IL1-b, IFN-γ, and IL-12), and chemokines (CXCL1, CXCL2, CCL2, CCL3, CCL4, and CXCL10). Thus, the IO nanoparticles is a novel, safe, and effective vaccine platform, with built-in adjuvancy, that is highly stable and field deployable for cost-effective vaccine delivery. [ABSTRACT FROM AUTHOR]

Asymmetric inorganic/organic composite nanoparticles with anisotropic surface functionalities represent a new approach for creating smart materials, requiring the selective introduction of chemical groups to dual components of composite, respectively. Here, we report the synthesis of snowman-like asymmetric silica/polystyrene heterostructure with anisotropic functionalities via a chemical method, creating nanostructure possibly offering two-sided biologic accessibility through the chemical groups. Carboxyl group was introduced to polystyrene component of the snowman-like composites by miniemulsion polymerization of monomer on local surface of silica particles. Moreover, amino group was then grafted to remained silica surface through facile surface modification of the composite nanoparticles. The asymmetric shape of these composites was confirmed by TEM characterization. Moreover, characteristics of anisotropic surface functionalities were indicated by Zeta potential measurement and confocal laser microscopy after being labeled with fluorescent dyes. This structure could find potential use as carriers for biological applications. [ABSTRACT FROM AUTHOR]

Nanopowders of Bi[sub 2]Ti[sub 2]O[sub 7] were synthesized by a metallorganic decomposition (MOD) technique. Pure Bi[sub 2]Ti[sub 2]O[sub 7] nanocrystals formed after annealing at 550°C for 5 min. X-ray patterns show that Bi[sub 20]TiO[sub 32] is a metastable phase during Bi[sub 2]Ti[sub 2]O[sub 7] formation. It was found that there were two peaks in the curves of the dielectric response as a function of temperature for pressed nanocrystalline Bi[sub 2]Ti[sub 2]O[sub 7] samples. The Curie temperature decreases with decrease of grain size whereas the ferroelectric-ferroelectric phase transition temperature increases. The hysteresis loops observed also suggest that Bi[sub 2]Ti[sub 2]O[sub 7] might belong to a ferroelectric material. [ABSTRACT FROM AUTHOR]

We present a new method to prepare TiO2 sea-urchin-like structures, which involves the initial formation of tubular nanostructures and subsequent self-assembly of the nanotubes into micrometer-scale sea-urchin-like structures. We also investigate the important role of alkali aqueous conditions in the preparation of TiO2 sea-urchin-like structures. This facile and cost-effective approach provides a new route for the preparation of self-assembled TiO2 structures. In addition, the performance of the as-synthesized TiO2 sea-urchin-like structures as the active layer of an efficient solar energy harvester is also studied and discussed. [ABSTRACT FROM AUTHOR]