Sharif Digital Repository

A titanium dioxide nanotube (TNT) and CuO-doped TNT (TNT-CuO) were synthesized using a hydrothermal method and incorporated into carrageenan-based films. The SEM results confirmed the formation of uniform nanocomposite films. The addition of nanoparticles imparted UV-blocking properties to the carrageenan film and increased the mechanical strength, surface hydrophobicity, and water vapor barrier properties. The modified TiO2 (TNT and TNT-CuO)-incorporated carrageenan films showed significantly higher antibacterial activity than the TiO2-added film under visible light. Bananas packaged with the neat carrageenan and TiO2-added films were degraded considerably after 12 days of storage at 20 °C.... 

Titanium dioxide (TiO2) and Cu-doped TiO2 (Cu–TiO2) were synthesized using a sol-gel method and used as nanofillers to prepare CMC-based functional packaging films. The Cu–TiO2 was spherical particles with a size range of 66.1 ± 9.0 nm TiO2 and Cu–TiO2 nanoparticles had good compatibility with CMC and were evenly distributed in the CMC polymer matrix to form a composite film. The TiO2-added film did not show significant antibacterial activity, but the Cu–TiO2-added film exhibited high antibacterial activity against foodborne pathogenic bacteria (L. monocytogenes and E. coli) under visible light. When bananas were packaged with the CMC-based films, the CMC/Cu–TiO2 film effectively delayed the... 

Gelatin-based functional films were prepared by the addition of grapefruit seed extract (GSE, 5 wt% based on gelatin) and various amounts of TiO2 (0.5, 1.0, 3.0, and 5.0 wt% based on gelatin). TiO2 was evenly dispersed in the gelatin film, but the film surface roughness was increased as the concentration of TiO2 increased. The mechanical strength and water contact angle (WCA) of the composite film were the highest, while the water vapor permeability (WVP) was the lowest when 0.5 wt% TiO2 was used. The addition of GSE slightly reduced the UV light transmittance, but the addition of TiO2 almost completely prevented the UV light transmission. The addition of GSE and TiO2 did not significantly... 

TiO2 nanotubes (TNTs) were synthesized hydrothermally and modified by Cu2O using a sol-gel method to provide photocatalytic activity in visible light. Cellulose nanofiber (CNF)-based films were prepared by adding TiO2, TNTs, and Cu2O-modified TNT (TNT-Cu2O). The TiO2-based nanoparticles (TiO2, TNTs, and TNT-Cu2O) were uniformly distributed in the base polymer to make compatible and flexible films. The incorporation of nanoparticles significantly enhanced the UV-shielding properties of the film while slightly decreasing the transparency. Incorporating nanofillers improved the film's mechanical and water resistance properties depending on the nanoparticle type. The TNT-Cu2O-added CNF film... 

Sulfur quantum dots (SQDs) were fabricated using a facile hydrothermal method and used for the preparation of functional food packaging film and compared the properties with other sulfur-based fillers like elemental sulfur (ES) and sulfur nanoparticles (SNP). The SQDs have an average size of 5.3 nm and were very stable in aqueous suspension. Unlike other sulfur-based fillers, the SQD showed high antioxidant, antibacterial and antifungal activity, but no cytotoxicity was found for L929 mouse fibroblasts even after long-term exposure of 48 h. When sulfur-based fillers were added to the alginate film, SQD was more evenly dispersed in the polymer matrix than SNP and ES. The addition of SQD to... 

Titanium nanotubes (TNTs) were prepared using TiO2 and decorated with CuO and Cu2O to have photocatalytic efficiency under visible light. TNTs decorated with copper oxides (TNT-CuO and TNT-Cu2O) were confirmed by the elemental mapping and XPS results. Unlike TNT and TiO2, TNT-CuO and TNT-Cu2O showed higher photocatalytic activity, such as antimicrobial and ethylene scavenging activities under visible light. Between the two types of copper oxide-decorated TNTs, TNT-Cu2O showed photocatalytic activity higher than that of TNT-CuO. The ethylene scavenging activity of TNT-Cu2O was about 40% higher than that of TNTs and TNT-CuO. The photocatalytic activity of titanium-based nanoparticles was... 

In photoacoustic tomography (PAT) systems, the tangential resolution decreases due to the finite size of the transducer as the off-center distance increases. To address this problem, we propose a multi-angle detection approach in which the transducer used for data acquisition rotates around its center (with specific angles) as well as around the scanning center. The angles are calculated based on the central frequency and diameter of the transducer and the radius of the region-of-interest (ROI). Simulations with point-like absorbers (for point-spread-function evaluation) and a vasculature phantom (for quality assessment), and experiments with ten 0.5 mm-diameter pencil leads and a leaf...