RESUMO
The steel of Damascus blades, which were first encountered by the Crusaders when fighting against Muslims, had features not found in European steels--a characteristic wavy banding pattern known as damask, extraordinary mechanical properties, and an exceptionally sharp cutting edge. Here we use high-resolution transmission electron microscopy to examine a sample of Damascus sabre steel from the seventeenth century and find that it contains carbon nanotubes as well as cementite nanowires. This microstructure may offer insight into the beautiful banding pattern of the ultrahigh-carbon steel created from an ancient recipe that was lost long ago.
RESUMO
This paper reports the first results of studies made to determine the antiviral activity of dioxo hexahydro triazine, a newly developed antiphytoviral compound. After treatment with dioxo hexahydro triazine, the concentration of helical potato virus X in leaves of Nicotiana tabacum "Samsun" was found to be considerably reduced in both the serological test and local lesion test conducted on Nicotiana glutinosa at temperatures of 14 degrees C +/- 3 degrees C. In secondarily infected leaves, the reduction of the concentration of potato virus X in the range of from 1 mol/l to 10(-3) mol/l was so that it was no longer possible for viruses to be detected serologically. In vitro, however, dioxo hexahydro triazine, which was added to the inoculum, did not produce a significant change in the activity of the virion of potato virus X. Therefore, it is reasonable to assume that dioxo hexahydro triazine tends to affect replication steps of viruses. The use of dioxo hexahydro triazine also had the effect of greatly and highly significantly reducing the concentration of the isodiametric cucumber mosaic virus.
