Gold nanoparticles (AuNPs) are commonly synthesized using the citrate reduction method, reducing Au 3+ into Au 1+ ions and facilitating the disproportionation of aurous species to Au atoms (Au 0 ). This method results on citrate-capped AuNPs with valence single states Au 0 . Here, we report a methodology that allows obtaining AuNPs by the dewetting process with three different valence states (Au 3+ , Au 1+ , and Au 0 ), which can be fine-tuned with ion bombardment. The chemical surface changes and binding state of the NPs were investigated using core-level X-ray photoelectron spectroscopy (XPS). This is achieved by recording high-resolution Au 4f XPS spectra as a function of ion dose exposure. The results obtained show a time-dependent tuning effect on the Au valence states using low-energy 200 V acceleration voltage Ar + ion bombardment, and the valence state conversion kinetics involves the reduction from Au 3+ and Au 1+ to Au 0 . Proper control of the reduction in the valence states is critical in surface engineering for controlling catalytic reactions.

Purpose: A study to evaluate the effectiveness of a modified procedure to correct involutional entropion. Methods: Seventeen cases of involutional entropion underwent surgery and had a postoperative follow-up of 18 months. The authors describe a technique of vertically shortening the anterior lamella (skin and orbicularis muscle), using a blepharoplasty incision and reflection of a skin muscle flap. Results: In 16 of 17 eyelids affected by involutional entropion, this operative procedure showed good functional outcome (good correction of the relation between lower eyelid edge and eyeball) and aesthetic outcome (no hypertrophic scar, dyschromia or unnatural folding of the skin). Conclusions: A correct approach to entropion surgery needs an accurate preoperative evaluation of the individual physiopathogenic factors. This procedure gives lasting functional and pleasing cosmetic results when preseptal orbicularis muscle override has been identified as the cause of senile entropion.

This work presents the results of the production and characterization of silver nanoparticles (AgNPs) to applications in Time Temperature Indicators (TTIs). AgNPs were synthetized by chemical processes. The suspensions (AgNPs in water) were characterized for different temperatures (4°C and 22°C) and time (0 to 5h). The AgNPs were characterized by energy dispersive X-ray spectrometry (EDS), UV–vis spectrophotometry and dynamic light scattering (DLS). AgNPs with diameters between 40 to 160nm were produced. The UV-Vis spectra reveal a characteristic absorption peak of the Ag in 420nm. This suspension shows shifts in the emission wavelength when exposed to room temperature compared to when exposed to a temperature of 4°C for different periods of time. Δλ = 20nm in the absorption spectra were found. Size distribution showed that the nanoparticles size decreases from 164 ±8 nm to 44±3 nm in the period of time studied. Suspension with nanoparticles concentration of 1,26· 10-10 M were obtained. TTIs manufactured with nanomaterials base its operation on the variations of the characteristics of nanoparticles suspended due to absorbing heat.