Nanostructured TiO2 photocatalyst and pump-probe spectroscopic study

Titanium dioxide (TiO₂), with its large band gap, has attracted much attention due to its excellent photocatalytic activity. TiO₂ ball-shaped nano-particles were deposited on silicon substrates by a thermal oxidation approach. With an increase in the annealing temperature the surface morphology and the structure of TiO₂ remained stable, exhibiting good heat stability; meanwhile, the hydrogen production rate also increased. The femtosecond pump-probe spectroscopic study showed that the lifetime of carriers of the samples as- deposited and post-annealed at different temperatures were longer than 20 ps.     

Accelerated formation of barium titanate by solid-state reaction in water vapour atmosphere

Barium titanate (BaTiO₃) powders were synthesized from commercially available raw materials (BaCO₃ and rutile) without particular mechanochemical processing by solid-state reactions in water vapour atmosphere. The formation rate of BaTiO₃ was accelerated by water vapour and single phase of BaTiO₃ was obtained by calcination at 700 °C for 4 h in water vapour atmosphere, though high temperature (850 °C for 2.5 h) was required by calcinations in air to complete the reaction. The formation kinetics followed the Valensi–Carter equation, which suggested that the reaction proceeded by a diffusion controlled process. The apparent activation energy for the formation of BaTiO₃ in air and water vapour atmosphere was estimated to be 361 ± 20 kJ/mol and 142 ± 17 kJ/mol, respectively. Water vapour is considered to enhance thermal decomposition of BaCO₃ and formation of BaTiO₃ by attacking surface Ti–O–Ti bonds in TiO₂, increasing partial pressure of Ba(OH)₂, and producing vacancies in the BaTiO₃ structure.     

Contribution of the Estrogen-Degrading Bacterium Novosphingobium sp. Strain JEM-1 to Estrogen Removal in Wastewater Treatment

This study aimed to investigate the contribution to estrogen removal from the activated sludge of an estrogen-degrading bacterium, Novosphingobium sp. Strain JEM-1, isolated by the writers from the activated sludge. The cell numbers of the Strain JEM-1 were investigated in two full-scale wastewater-treatment plants using real-time PCR. Strain JEM-1 appears to be commonly distributed in the activated sludge. The cell numbers of Strain JEM-1 in the oxidation ditch process were higher than those in the conventional activated sludge (CAS) process, and the effluent concentrations of E1 in the CAS process tended to decrease with increased cell numbers of Strain JEM-1. In a bench-scale experiment to investigate bioaugmentation with Strain JEM-1, there was a significant difference in the effluent concentrations of estrogens between the experimental series and the control series. Linear relationships were observed between cell numbers of Strain JEM-1 and the efficiency of removal of estrogens. These results suggest that Strain JEM-1 contributes to the estrogen removal in the activated sludge.     

Prospect of gene therapy for metastatic foci of gastric cancer

Surgical excision of both primary and metastatic tumors is the recommended therapy for gastric cancer. There are many cases of multiple metastasis to lymph nodes, disseminated metastasis of peritoneum, and post-operative systemic metastasis for which no surgical treatment is available. Cancer gene therapy is one of the promising new techniques. We injected the suicide gene, herpes simplex virus thymidine kinase (HSV-tk), directly into the tumor using gastrofiberscopy. Following GCV treatment caused tissue degeneration at the injection site and lymph nodes. These findings show that suicide gene therapy for gastric cancer may be effective for a metastatic tumor along with the primary tumor.     

Agreement between predicted risk and prevalence of Down syndrome in second-trimester triple-marker screening in Japan

Based on 9350 pregnant Japanese women who were screened by serum triple-marker determination, accuracy of predicted risk for Down syndrome was examined using 24 Down syndrome cases detected either prenatally or postnatally. The correlation is statistically very high (r = 0.98) between the predicted risks and the prevalence of Down syndrome cases. Here we emphasize that this could be accomplished only by an extensive follow-up study, implemented in our prospective intervention programme.     

Cycle analysis using exhaust heat of SOFC and turbine combined cycle by absorption chiller

The power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300^°C. Thus, it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. We propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500‐kW‐class SOFC, the bottoming single‐effect absorption chiller can produce a refrigerating capacity of about 120 kW, and the double‐effect absorption chiller can produce a little higher refrigerating capacity of about 130 kW without any additional fuel. But the double‐effect absorption chiller became more expensive and complex than the single‐effect chiller. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 49– 55, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20578