Manuel Fernando Gonzalez Huila

Confocal Raman and electronic microscopy studies on the topotactic conversion of calcium carbonate from Pomacea lineate shells into hydroxyapatite bioceramic materials in phosphate media.

Conversion of Pomacea lineate shells into hydroxyapatite (HA) bioceramic materials was investigated by their in vitro treatment with phosphate solutions, at room temperature. Confocal Raman microscopy revealed that the conversion proceeds at distinct rates through the nacreous or periostracum sides of the shell. The conversion can be accelerated using powdered samples, yielding biocompatible materials of great interest in biomedicine.

N3-dye-induced visible laser anatase-to-rutile phase transition on mesoporous TiO2 films.

Titanium dioxide has been extensively used in photocatalysis and dye-sensitized solar cells, where control of the anatase-to-rutile phase transformation may allow the realization of more efficient devices exploiting the synergic effects at anatase/rutile interfaces. Thus, a systematic study showing the proof of concept of a dye-induced morphological transition and an anatase-to-rutile transition based on visible laser (532 nm) and nano/micro patterning of mesoporous anatase (Degussa P25 TiO(2)) films is described for the first time using a confocal Raman microscope. At low laser intensities, only the bleaching of the adsorbed N3 dye was observed. However, high enough temperatures to promote melting/densification processes and create a deep hole at the focus and an extensive phase transformation in the surrounding material were achieved using 1s laser pulses of 25-41 mW/cm(2), in resonance with the MLCT band. The dye was shown to play a key role, being responsible for the absorption and efficient conversion of the laser light into heat. As a matter of fact, the dye is photothermally decomposed to amorphous carbon or to gaseous species (CO(x), NO(x), and H(2)O) under a N(2) or O(2) atmosphere, respectively.

Gold Nanohole Arrays Fabricated by Interference Lithography Technique as SERS Probes for Chemical Species Such As Rhodamine 6G and 4,4′-Bipyridine

In the present study, we report the SERS effect of rhodamine 6G (Rh6G) and 4-4′ bipyridine (Bipy) molecules on the surface of gold nanohole (AuNh) arrays fabricated by the interference lithography (IL) technique. It was observed an enhancement of the main bands of Rh6G and 4-4′ Bipy molecules, when deposited over the surface of AuNh, in comparison when that was deposited on the surface of 5-nm flat gold film. Our study indicates that metallic nanostructures fabricated by IL technique have the potential for high impact on biochemical sensing, such as DNA and bacterial detection, real time glucose sensing for diabetes, and in situ identification of reaction products.

Unraveling the Mysterious Role of Palladium in Feigl bis(dimethylglyoximate)nickel(II) Spot Tests by Means of Confocal Raman Microscopy

The acid protection effect promoted by traces of PdCl(2) in [Ni(dmgH)(2)] spot tests was elucidated from confocal Raman microscopy imaging, which revealed the formation of protecting layers of [Pd(dmgH)(2)] closing the extremities of the [Ni(dmgH)(2)] filaments.

Correction to: Can in vivo surface dental enamel microbiopsies be used to measure remote lead exposure?

To accomplish the aim A, lead from 90 bovine incisor crowns was determined by graphite furnace atomic absorption spectrometer as a function of exposure time and lead concentration.

Effect of ethanol concentrations on few layer Schottky graphene transistors

We have studied the effect of positive and negative back gate voltage on the Schottky barrier of few layer graphene transistors (devices) in the presence of Air, Nitrogen and different ethanol vapor concentrations. The presence of the Schottky barrier in these devices is attributed to unintentional doping of the different areas of the graphene flake and is modulated by applying a positive gate voltage, increasing the source-drain current.