Electroluminescence stabilization of nanocrystalline porous silicon diodes

NRC publication: Ye

Interaction of 4 allotropic modifications of carbon nanoparticles with living tissues

Environmental pollution and technological progress lead to carbon nanoparticles that pose a serious health risk. They are present in soot, dust, and printing toner and can also be formed during grinding and cutting. Human neutrophils are able to sequester foreign material by formation of neutrophil extracellular traps (NETs), a process that can cause a strong inflammatory response. In the current work we compared proinflammatory properties of different carbon-based nanostructures: nanodiamonds, graphene oxide, fullere­nes C60 and carbon dots. We tested adjuvant properties of carbon nanoparticles in a murine immunization model by investigating humoral (specific IgG and IgM antibodies) and cellular (delayed type hypersensitivity) immune responses. The ability of NETs to sequester nanoparticles was analyzed in a mouse air pouch model and neutrophil activation was verified by in vivo tracking of near-infrared labeled nanodiamonds and ex vivo fluorescent assays using human blood-derived neutrophils. All carbon nanoparticles exhibited proinflammatory adjuvant-like properties by stimulating production of specific IgG but not IgM antibodies (humoral immune response). The adjuvant-like response decreased in this order: from nanodiamonds, graphene oxide, fullerenes C60 to carbon dots. None of the studied carbon nanoparticles triggered a delayed type hypersensitivity reaction (cellular immune response). Nanodiamonds and fullerenes C60 were sequestrated in the body by NETs, as confirmed in the air pouch model and by in vivo fluorescent tracking of near-infrared labeled nanodiamonds

First-Principles Study of the Band Gap Structure of Oxygen-Passivated Silicon Nanonets

A net-like nanostructure of silicon named silicon nanonet was designed and oxygen atoms were used to passivate the dangling bonds. First-principles calculation based on density functional theory with the generalized gradient approximation (GGA) were carried out to investigate the energy band gap structure of this special structure. The calculation results show that the indirect–direct band gap transition occurs when the nanonets are properly designed. This band gap transition is dominated by the passivation bonds, porosities as well as pore array distributions. It is also proved that Si–O–Si is an effective passivation bond which can change the band gap structure of the nanonets. These results provide another way to achieve a practical silicon-based light source

Wettability Switching Techniques on Superhydrophobic Surfaces

The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However, the dynamic modification of the liquid droplets behavior and in particular of their wetting properties on these surfaces is still a challenging issue. In this review, after a brief overview on superhydrophobic states definition, the techniques leading to the modification of wettability behavior on superhydrophobic surfaces under specific conditions: optical, magnetic, mechanical, chemical, thermal are discussed. Finally, a focus on electrowetting is made from historical phenomenon pointed out some decades ago on classical planar hydrophobic surfaces to recent breakthrough obtained on superhydrophobic surfaces