Field Evaluation of a PCR Test for Schistosoma japonicum Egg Detection in Low-Prevalence Regions of China

Sensitive Schistosoma japonicum detection methods are needed to progress from schistosomiasis control to elimination. The sensitivity of the Kato-Katz thick smear and miracidium hatching tests decrease with infection intensity and serological tests cannot always identify current infections. We evaluated a fecal polymerase chain reaction (PCR) assay to detect S. japonicum infection in 106 humans and 8 bovines in China. PCR was highly sensitive, detecting S. japonicum DNA at 0.5 eggs/g of stool. Comparing PCR examination of a single stool sample to the miracidium hatching test using three consecutive stool samples, more humans were hatching test positive (20%) than PCR positive (15%). However, two individuals were PCR positive in a village where no infections were detected by coprological methods. The sensitivity of PCR makes it a promising tool for schistosomiasis diagnostics and screening, although egg shedding variability and stool sample size present challenges for any detection method in low-transmission areas.     

Elucidation of the electron energy structure of TiO2(B) and anatase photocatalysts through analysis of electron trap density

A clear understanding of the electron energy structure of TiO₂(B)/anatase is needed to study the related catalytic reactions and design new composite photocatalysts. In this study, the electron energy structures of TiO₂(B) and anatase were estimated by analyzing the energy-resolved distribution of electron traps measured by reversed double-beam photoacoustic spectroscopy. In the mixture of TiO₂(B) and anatase, interfacial charge-transfer excitation from anatase to electron traps of TiO₂(B) was suggested. By analyzing this for TiO₂(B), the electron level with a relatively high density of states was found to be located ∼0.07 eV deeper than that for anatase. Furthermore, a similar electron energy structure was suggested for a composite photocatalyst having a mixed phase of TiO₂(B) and anatase.

The electron energy structures of TiO₂(B) and anatase were estimated by analyzing the energy-resolved distribution of electron traps.