A composite semiconductor electrode with the structure "n-Si/p-CuI/ITO/n-i-p a-Si/n-p GaP/ITO/RuO 2 " was fabricated for the purpose of achieving efficient solar water splitting. The electrode showed a stable photoanodic current due to oxygen evolution with a large negative photoshift (V p ) of about 2.2 V from an anodic current at a RuO 2 electrode. The photoshift was large enough for full water splitting. A photoelectrochemical (PEC) cell, composed of the composite electrode, a Pt counter electrode, and 0.10 M Na 2 SO 4 (pH 6.3), generated a photocurrent density of 1.88 mA cm -2 under simulated solar illumination (AM 1.5 G, 100 mW cm -2 ), yielding a solar to chemical conversion efficiency of 2.3% as calculated from the photocurrent value. The result has shown that the combination of "crystalline Si/a-Si/GaP" is suitable for efficient solar water splitting. It is shown that the efficiency can be increased by use of GaP with a well-regulated p-n junction.

Solar cells with a structure of p-n heterojunction, "ITO/p-CuI/n-Si" (ITO ) indium tin oxide), were fabricated by depositing p-CuI on hydrogen (H)-terminated or methyl (CH 3 )-terminated single-crystal n-Si (111) followed by the sputter deposition of ITO or by the press-contact of commercial conductive oxide glass with p-CuI. The solar cells generated very high open-circuit photovoltages (V oc ), reaching 0.617 V without surface texturing and back surface field treatments. Experiments have shown that a morphologically soft property of p-CuI as well as a low density of surface states at H-terminated or CH 3 -terminated n-Si (111) is responsible for the generation of high V oc . Theoretical investigation has also shown that the p-CuI/n-Si contact forms an ideal minority-carrier controlled junction suitable for the generation of high V oc .

To specify critical factors responsible for Pseudomonas aeruginosa penetration through the Caco-2 cell epithelial barrier, we analyzed transposon insertion mutants that demonstrated a dramatic reduction in penetration activity relative to P. aeruginosa PAO1 strain. From these strains, mutations could be grouped into five classes, specifically flagellin-associated genes, pili-associated genes, heat-shock protein genes, genes related to the glycolytic pathway, and biosynthesis-related genes. Of these mutants, we here focused on the serA mutant, as the association between this gene and penetration activity is yet unknown. Inactivation of the serA gene caused significant repression of bacterial penetration through Caco-2 cell monolayers with decreased swimming and swarming motilities, bacterial adherence, and fly mortality rate, as well as repression of ExoS secretion; however, twitching motility was not affected. Furthermore, L-serine, which is known to inhibit the D-3-phosphoglycerate dehydrogenase activity of the SerA protein, caused significant reductions in penetration through Caco-2 cell monolayers, swarming and swimming motilities, bacterial adherence to Caco-2 cells, and virulence in flies in the wild-type P. aeruginosa PAO1 strain. Together, these results suggest that serA is associated with bacterial motility and adherence, which are mediated by flagella that play a key role in the penetration of P. aeruginosa through Caco-2 cell monolayers. Oral administration of L-serine to compromised hosts might have the potential to interfere with bacterial translocation and prevent septicemia caused by P. aeruginosa through inhibition of serA function.

A Si(111) surface modified with alpha,beta-unsaturated carboxyl groups was fabricated using activated alkynes such as propiolic acid and propiolic acid methyl ester via hydrosilylation reaction. The obtained coverage of carboxyl groups was roughly estimated to be 55-60% in both cases from the Si-2p and C-1s X-ray photoelectron specroscopy (XPS) peak intensities. The detailed surface structures were investigated by multiple internal reflection Fourier transform infrared (MIR-FTIR) measurement. It was revealed that this reaction was promoted by visible light irradiation at room temperature. The Si surface modified with functional groups prepared under such a moderate condition is adaptable to functional devices which are easily damaged under UV irradiation or high temperature conditions.