Core-shell nanomaterials have been one of the most attracting research targets in the field of nanoscience and technology due to the multiple functionalities contributed from different components. In this paper, we report a facile solution synthetic method for the preparation of gold-nickel phosphide core-shell nanoparticles that have a near-spherical morphology and a size of ~20 nm. Transmission electron microscopy along with energy dispersive X-ray spectroscopy analyses reveals a core-shell structure consisting of gold core and nickel phosphide shell. The optical absorption data show that the surface plasmon resonance band of gold in the visible range is greatly decreased by coating nickel phosphide shell. The result of magnetic measurement reveals that the as-prepared core-shell nanoparticles basically exhibit paramagnetic characteristics. The obtained gold-nickel phosphide core-shell nanoparticles can be applied in application fields such as catalysis.
Netrin-1 is a neural guidance cue that also regulates vascular development. Controversial results, however, have been obtained concerning the roles of netrin-1 in vascular development both in vivo and in vitro. In the present study, two in vitro angiogenesis assays were compared to evaluate the effects of netrin-1 secreted by retrovirally transduced melanoma cells (Mel2a-netrin1) on tube formation. The results showed that there was no obvious difference in tube formation induced by conditioned media (CM) from the control, Mel2a-netrin1 and Mel2a cells in a matrigel assay. The results of another in vitro assay, in which endothelial cells were co-cultured with human fibroblasts, however, showed that Mel2a-netrin1 CM inhibited the tube formation, supposedly through blocking the elongation and coalescence of human umbilical vein endothelial cells (HUVECs). These results confirmed that the matrigel assay is not able to demonstrate the anti-angiogenic roles of netrin-1.
A non-aqueous synthetic route has been developed for the preparation of uniform Cu nanowires with length up to tens of micrometers. Unlike commonly used one-pot synthesis approach that usually involve a fast reduction of metal precursors in the presence of reducing agents, a continuous-injection approach has been to utilized to control the speed of reaction and the concentration of Cu nuclei. In this approach, copper (II) chloride dihydrate and nickel (II) acetylacetone which are dissolved in oleylamine solutions have been injected into octadecene by a syringe-pump. The as-prepared samples have been characterized by transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results show that the products are pure Cu nanowires which have preferred <110> growth directions. The formation mechanism and major influencing factors on the synthesis of Cu nanowires have been discussed.
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