Different titanium oxide nanotubes were synthesized by anodizing the surface of titanium foil in two electrolyte solutions containing hydrofluoric acid and ethylene glycol. The samples were heat-treated in a furnace. The microstructure and phase transformations of the nanotubes were investigated by X-ray diffraction and field emission-scanning electron microscope. The nanoscale geometry of the nanotubes is responsible for the outstanding hydrogen gas sensitivities. A remarkable variation in electrical conductance has been observed in titanium oxide nanotube arrays that were prepared in hydrofluoric acid. This sensor exhibits a large resistance variation in the presence of very small quantities of hydrogen gas at 25 C. The sensors show reversibility, repeatability, negligible drift, and wide dynamic range.
Semitransparent organic solar cells have become attractive recently because of their photon harvesting in the near-infrared and ultraviolet range and passing in the visible light region. Semitransparent organic solar cells with ITO/ZnO/PBDB-T:ITIC/MoO3/Ag/MoO3 structure have been studied in this work and the effects of PBDB-T:ITIC active layer thicknesses and the transparent top electrode, MoO3/Ag/MoO3, thickness on the solar cell performance such as I-V characteristics, the power conversion efficiency, the average visible transmittance, and the color coordinates in the CIE color space are investigated. The drift–diffusion model, including the density of exactions, and their displacement is used to model the devices. The model is examined with experimentally reported devices, where there is a very good agreement between them, then is applied to the new structures. The obtained results show that the average visible transmittance of more than 45% is achievable for these structures with reasonable power conversion efficiency.
Rod-like mesoporous silica nanoparticles with pH-responsive amphiphilic hyperbranched polyester shells were prepared for doxorubicin (DOX) delivery. First, rod-shaped mesoporous silica nanoparticles (MSNs) were obtained, then hydrophobic hyperbranched polyester Boltorn H40 (H40) was grafted on their surface. The H40 coated MSNs were next treated with amine-functionalized polyethylene glycol (PEG) to achieve the hydrophilic and pH-responsive material denoted as PEG-H40-MSNs. The experimental results showed that PEG-H40-MSNs were successfully synthesized. BET analysis showed that rod MSNs exhibits a type IV standard isotherm. TEM revealed that the thin gray polymer layer was formed around the SBA-15 particle with a diameter of around 150 nm. DOX was effectively loaded, which can be released according to the ambient pH inside the cell as follow: at pH 7.4, only 9.7% of the DOX was released after 48 h; as the pH decreased to 5.5, the cumulative release reached to 49% at the same time. PEG-H40-MSNs showed less than 1.6% of hemolytic activity and a slight effect on the liver and kidney of treated mice were observed at a high disposal dosage implying negligible toxicities were caused by PEG-H40-MSNs in both in vitro hemolysis analysis and in vivo biochemical in mice. However, the in vitro cytotoxicity evaluation of the DOX-PEG-H40-MSNs showed that the cell cytotoxicity of both pure DOX and DOX-loaded PEG-H40-MSNs generally enhanced by increasing the concentration of DOX.
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