RESUMO
ß-MoO3 whiskers prepared by a thermal evaporation method and α-MoO3 particles were irradiated in a nuclear reactor to produce 99Mo/99mTc radioisotopes via neutron capture. The irradiated targets were then dispersed in water to extract the 99Mo/99mTc isotopes. Of the 99Mo formed in the ß-MoO3 whiskers, 64.0 ± 7.4% was extracted with water; by contrast, only 8.8 ± 2.6% of the 99Mo formed in α-MoO3 was extracted. By comparing these data to the 98Mo concentration dissolved in water, we confirmed the hot-atom effect on both ß-MoO3 whisker and α-MoO3 particle targets to transfer 99Mo isotopes from irradiated samples to water. In addition, the ß-MoO3 whiskers exhibited a prominent hot-atom effect to transfer a higher ratio of 99Mo isotopes into water. To the best of our knowledge, this research is the first demonstration of ß-MoO3 being used as an irradiation target in the neutron capture method. On the basis of the results, ß-MoO3 is considered a promising irradiation target for producing 99Mo/99mTc by neutron capture and using water for the radioisotope extraction process in the future.
RESUMO
Our previous studies found that a dominant serovar of Salmonella enterica isolates from three farms raising broilers in 2014 and 2015 was serovar Agona and the number of Infantis isolates decreased (the serovar shift). In this study, 52 S. Agona strains which isolated between 1993 and 2008, were compared to the serovar shift clone by molecular epidemiology and phylogenetic analyses, using pulsed field gel electrophoresis and whole genome sequence analyses. Of the 52 strains, one strain isolated from a human case in 1995 was genetically identical to the serovar shift clone, even though it was isolated prior to the serovar shift. These results suggested that the S. Agona serovar shift clone had existed in a source other than chicken penetrated chicken population.