In situ study of the effect of endogenous and exogenous agents on color stability, hardness, and surface roughness of an elastomer for facial prostheses.

Purpose: To evaluate in situ the influence of sweat, oil, sunscreen, and disinfectant solution on the color stability, hardness, and roughness of elastomer for facial prostheses.

Materials And Methods: Standardized and intrinsically pigmented specimens remained in contact with human skin from the same person for 30 days, considering exposures (n = 36 per group), absent of exposition (Control, C); sweat and oiliness contact (SO); sweat and oiliness associated with sunscreen (SOS); 0.12% chlorhexidine digluconate immersion (CD0.

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals.

Electron and hole transport characteristics were evaluated for perylene-based and pyrene-based compounds using electron-only and hole-only devices. The perylene presented a columnar hexagonal liquid crystal phase at room temperature with strong molecular π-stacking inside the columns. The pyrene crystallizes bellow 166 °C, preserving the close-packed columnar rectangular structure of the mesophase.

Ethylene scavenging properties from hydroxypropyl methylcellulose-TiO and gelatin-TiO nanocomposites on polyethylene supports for fruit application.

Several technologies have been proposed to preserve fruits and to avoid postharvest losses. The degradation of ethylene produced by the fruits using TiO photocatalysis has shown to be a good option to delay the ripening of fruits. This paper proposed a new application of biopolymers-TiO nanocomposites developed to extend the shelf-life of fruits.

Hydroxypropyl methylcellulose-TiO and gelatin-TiO nanocomposite films: Physicochemical and structural properties.

Photocatalytic properties of titanium dioxide (TiO) have been widely studied. However, its tendency to aggregation in biopolymer-based nanocomposites limits its application for food packaging and has been few studied. The aim of this work was to study the dispersion of TiO (0-2 wt%) incorporated in the hydroxypropyl methylcellulose (HPMC-TiO) and gelatin (gelatin-TiO) film forming solutions.

Surface damage of dental implant systems and ions release after exposure to fluoride and hydrogen peroxide.

Objective: The aim of this study was to evaluate surface changes on dental implant systems and ions release after immersion in fluoride and hydrogen peroxide.

Methods: Ten implant-abutment assemblies were embedded in acrylic resin and cross-sectioned along the implant vertical axis. Samples were wet ground and polished.

High rectification in organic diodes based on liquid crystalline phthalocyanines.

The optical and electrical properties of mesogenic metal-free and metalated phthalocyanines (PCs) with a moderately sized and regioregular alkyl periphery were investigated. In solution, the individualized molecules show fluorescence lifetimes of 4-6 ns in THF. When deposited as solid thin films the materials exhibit significantly shorter fluorescence lifetimes with bi-exponential decay (1.

Layer-by-layer assembled films composed of "charge matched" and "length matched" polysaccharides: self-patterning and unexpected effects of the degree of polymerization.

The functionalization of chitosan with carboxymethyl groups allows zwitterionic or anionic chitosan derivatives to be obtained as a function of the degree of substitution. Here, we show that polyelectrolyte multilayers of chitosan and carboxymethylchitosan can be assembled by "dipping" or "spraying" to form strongly hydrated films in which both the polyanion and polycation possess the same polymer backbone ("matched chemistries"). Such films grow rapidly to fairly large thickness in very few assembly steps, especially in the case of "matched" charge densities, and atomic force microscopy reveals the formation of surface patterns that are dependent on the deposition conditions and on the number of layers.