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The band gap formation during the first stages of growth of CdS thin films, deposited on glass substrates by chemical bath deposition (CBD) and close spaced sublimation (CSS) techniques was studied. To obtain the first stages of growth, we used deposition times between 5 and 40 min for CBD films, and 4–60 s for CSS films. CBD technique with two chemical bath agitation modalities — the traditional magnetic agitation and ultrasonic vibration — was used for film preparation. Morphological, structural, optical, and stoichiometrical results were obtained on each CdS films group. Higher values of the band gap energy (3.2 eV) were obtained for the thinnest films (2–3 nm) by CBD with ultrasonic vibration; others films, showed similar band gap energy values to those reported for polycrystalline CdS films (2.42 eV). Energy vs. α2 curves, presented strong differences between the two deposition techniques used. The behavior of the optical window effects, the surface roughness, the structural results, and the films thickness related to the deposition techniques are discussed. The CBD technique with ultrasonic vibration produces films with cleaner surfaces, controlled thickness and better optical properties.

The transcription factor Nurr1 is expressed in the mouse olfactory bulb (OB), although it remains unknown whether it influences the generation of dopaminergic neurons (DA) (DA neurons) in cells isolated from this brain region. We found that expressing Nurr1 in proliferating olfactory bulb stem cells (OBSCs) produces a marked inhibition of cell proliferation and the generation of immature neurons immunoreactive for tyrosine hydroxylase (TH) concomitant with marked upregulations of Th, Dat, Gad, and Fgfr2 transcripts. In long-term cultures, these cells develop neurochemical and synaptic markers of mature-like mesencephalic DA neurons, expressing GIRK2, VMAT2, DAT, calretinin, calbindin, synapsin-I, and SV2. Concurring with the increase in both Th and Gad expression, a subpopulation of induced cells was both TH- and GAD- immunoreactive indicating that they are dopaminergic- GABAergic neurons. Indeed, these cells could mature to express VGAT, suggesting they can uptake and store GABA in vesicles. Remarkably, the dopamine Dl receptor agonist SKF-38393 induced c-Fos in TH(+) cells and dopamine release was detected in these cultures under basal and KCl-evoked conditions. By contrast, cotransducing the Neurogenin2 and Nurr1 transcription factors produced a significant decrease in the number of TH- positive neurons. Our results indicate that Nurr1 overexpression in OBSCs induces the formation of two populations of mature dopaminergic neurons with features of the ventral mesencephalon or of the OB, capable of responding to functional dopaminergic stimuli and of releasing dopamine. They also suggest that the accumulation of Fgfr2 by Nurr1 in OBSCs may be involved in the generation of DA neurons.