Multifunctional behavior of molecules comprising stacked cytosine-Ag-cytosine base pairs; towards conducting and photoluminescence silver-DNA nanowires.

DNA molecules containing a 1D silver array may be applied for nanotechnology applications, but first their conducting and photoluminescence behavior must be enhanced. Here we have synthesized and characterized three new helical compounds based on stacked silver-mediated cytosine base pairs [Ag(mC)]X (mC = N1-methylcytosine; X = NO (), BF () and ClO ()), that contain uninterrupted polymeric Ag chains that run through the center of the helixes, comparable to related silver-DNA structures. The exposure of nanostructures of [Ag(mC)]BF () to cold hydrogen plasma stimulates the reduction of the prearranged Ag polymeric chains to metallic silver along the material.

Grafting the surface of carbon nanotubes and carbon black with the chemical properties of hyperbranched polyamines.

Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials.

Effect of 30 % hydrogen peroxide on mineral chemical composition and surface morphology of bovine enamel.

A combination of atomic absorption spectroscopy (AAS), Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), and gas adsorption techniques was used to characterize the effect of 30 % hydrogen peroxide (HP) on enamel surface. To perform the analyses of AAS, 1 ml of 30 % HP was added to 30 mg of a bovine enamel powder sample (150-200 µm fractions) for times of 5, 20, 60, 90, and 120 min; then 5 ml of the solution was withdrawn after each time period to measure [Ca(2+)] ions. The remaining powder was recovered and analyzed by FTIR.

Surface characteristics of activated carbons obtained by pyrolysis of plasma pretreated PET.

Activated carbon materials have been prepared by pyrolysis of plasma pretreated recycled PET. The obtained carbon materials have been texturally characterized by N2 (77 K) and CO2 (273 K) adsorption. Atomic force microscopy (AFM) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) have been used to analyze the surface of the treated precursors.