ABSTRACT
TiO2 is a significant n-type semiconducting material because of its superior electric and photocatalytic properties. Although this material has been extensively studied as a semiconductor electrode for dye-sensitized solar cells for its inherent bandgap and its excellent electrical and chemical properties, the photoelectric efficiency is nevertheless lower than that of the Si-based solar cells, which is generally reported as 13-27%. On the other hand, various carbon structures have been studied to increase the overall charge transport efficiency by reducing the charge transport resistance in the cell while having high electric conductivity. These results are expected to improve the photoelectric conversion efficiency when applied to dye-sensitized solar cells. We fabricated a TiO2/multi-wall carbon nanotube (MWCNT) core-shell structure by a hydrothermal method. The TiO2 anatase phase in the TiO2/MWCNT core-shell structure was confirmed by X-ray diffraction (XRD). The core-shell nanostructure with a diameter of 127 nm to 211 nm was observed by field emission scanning electron microscope (FE-SEM). The morphology of the TiO2/MWCNT core-shell nanocomposite was also analyzed by transmission electron microscope (TEM). The Fourier-Transform Infrared Spectrometer (FT-IR) and Brunauer Emmett and Teller (BET) method were used to observe the chemical bonding and specific surface area of the TiO2/MWCNT core-shell nanocomposite, respectively. The TiO2/MWCNT core-shell composites had a larger specific surface area of 92.00 m²/g, a larger pore volume of 0.33 cm³/g, and a larger pore size of 65.21 nm than commercial TiO2 nanoparticles (P25). The TiO2/MWCNT core-shell structure may provide a high-speed path for photoelectrons to pass quickly and will be useful for various applications, such as solar cells and photocatalysts.
ABSTRACT
In order to investigate the underlying mechanism of HCl in oesophagitis, the inflammatory response to HCl was observed in RBL-2H3 mast cells. Rat basophilic leukemia (RBL-2H3) cells were used to measure histamine release, arachidonic acid (AA) release, reactive oxygen species (ROS) and peroxynitrite generation induced by HCl. Exogenous HCl increased the level of histamine release and ROS generation in a dose dependent manner, whereas it decreased the spontaneous release of [3H] AA and the spontaneous production of peroxynitrite. Mepacrine (10 microM), oleyloxyethyl phosphorylcholine (10 microM) and bromoenol lactone (10 microM) did not affect both the level of histamine release and ROS generation induced by HCl. U73122 (1 microM), a specific phospholipase C (PLC) inhibitor did not have any influence on level of histamine release and ROS generation. Propranolol (200 microM), a phospholipase D (PLD) inhibitor, and neomycin (1 mM), a nonspecific PLC and PLD inhibitor, significantly inhibited both histamine release and ROS generation. Diphenyleneiodonium (10 microM), a NADPH oxidase inhibitor, and tiron (5 mM), an intracellular ROS scavenger significantly inhibited the HCl-induced histamine release and ROS generation. These findings suggest that the inflammatory responses to HCl is related to histamine release and ROS generation, and that the ROS generation by HCl may be involved in histamine release via the PLD pathway in RBL-2H3 cells.
