A Thermoelectric Energy Harvester Based on Microstructured Quasicrystalline Solar Absorber.

As solar radiation is the most plentiful energy source on earth, thermoelectric energy harvesting emerges as an interesting solution for the Internet of Things (IoTs) in outdoor applications, particularly using semiconductor thermoelectric generators (TEGs) to power IoT devices. However, when a TEG is under solar radiation, the temperature gradient through TEG is minor, meaning that the TEG is useless. A method to keep a significant temperature gradient on a TEG is by using a solar absorber on one side for heating and a heat sink on the other side.

Self-lubricating, low-friction, wear-resistant Al-based quasicrystalline coatings.

After gas atomization, a quasicrystalline powder based on aluminium was used to prepare a thick coating by high-velocity oxygen-fuel flame torch spraying. This layer was deposited on top of a bond-coat layer on a steel plate. A post-spraying annealing treatment turned the two layers to their stable state, a γ-brass crystal and an icosahedral quasicrystal, respectively.

Effect of time and pH on physical-chemical properties of orthodontic brackets and wires.

Objective: To test the hypothesis that treatment time, debris/biofilm, and oral pH have an influence on the physical-chemical properties of orthodontic brackets and arch wires.

Materials And Methods: One hundred twenty metal brackets were evaluated. They were divided into four groups (n  =  30) according to treatment time: group C (control) and groups T12, T24, and T36 (brackets recovered after 12, 24, and 36 months of treatment, respectively).

In vitro effects of nano-hydroxyapatite paste on initial enamel carious lesions.

Purpose: The purpose of this study was to analyze the protective effect of remineralizing agents on enamel caries lesions using surface Knoop microhardness testing (KHN) and atomic force microscopy (AFM).

Methods: Forty-eight human enamel blocks were assigned to four groups (N=12): (1) control (without agent); (2) fluoride varnish (Duraphat); (3) nano-HAP paste (Desensibilize Nano P); and (4) casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (MI Paste Plus). Incipient caries-like lesions were artificially developed.

In Vitro Effects of Nano-hydroxyapatite Paste on Initial Enamel Carious Lesions.

Purpose: The purpose of this study was to analyze the protective effect of remineralizing agents on enamel caries lesions using surface Knoop microhardness testing (KHN) and atomic force microscopy (AFM).

Methods: Forty-eight human enamel blocks were assigned to four groups (N=12): (1) control (without agent); (2) fluoride varnish (Duraphat); (3) nano-HAP paste (Desensibilize Nano P); and (4) casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (MI Paste Plus). Incipient caries-like lesions were artificially developed.

Protective effect of calcium nanophosphate and CPP-ACP agents on enamel erosion.

The aim of this study was to assess the effect of different remineralizing agents on enamel microhardness (KHN) and surface topography after an erosive challenge. Forty-eight human enamel specimens (4 × 4 mm) were randomly assigned to 4 groups: control (no treatment), fluoride varnish, calcium nanophosphate paste and casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP). Both pastes were applied for 5 minutes, and fluoride varnish, for 24 h.

In vitro effect of calcium nanophosphate and high-concentrated fluoride agents on enamel erosion: an AFM study.

Background: Calcium nanophosphate paste can provide ions to remineralize enamel. There are, however, no data available about the remineralizing effect of this paste on the prevention of enamel erosion, when compared with highly concentrated fluoride agents.

Aim: To analyze the effect of calcium nanophosphate paste, fluoride gel, and varnish to protect against enamel erosion using surface Knoop hardness (KNH) and atomic force microscopy (AFM).