By monitoring the vertical motion of the tip of a scanning tunneling microscope (STM) during atomic manipulation on a surface, we have been able to detect for the first timeÅngstrom-scale displacements of the tip which are associated with the extraction and deposition of atoms on the surface, due to voltage pulses applied to the sample. The temporal distribution of these tip displacements during and after the application of the voltage pulse yields important information about the nature of the modification process.
It has been clarified, through many investigations and studies on earthquake response of buried pipes and tunnels, that underground structures follow closely the motion of the surrounding soil. Thus, it is of great importance to study the seismic response of a soft soil deposit overlying uneven bedrock. An efficient numerical model is developed for this purpose. The model is a synthesis of lumped-mass-spring systems linked up by a finite element net. Good agreement between observed ground tremor and numerical one validates the present approach.
Based on the complete nucleotide sequences of sweet clover necrotic mosaic virus (SCNMV) genome, full-length cDNA clones derived from RNA-1 and RNA-2 were constructed by the polymerase chain reaction with proper primers. RNA-1 and RNA-2 transcripts capped or uncapped with m7GpppG were efficiently generated, were infectious and induced symptoms identical with those caused by native viral RNAs when coinoculated to test plants Chenopodium quinoa, C. amaranticolor and Phaseolusvulgaris 'Red Kidney' bean. However, infectivity of these transcripts were less than that of the native viral RNA. In addition, the uncapped transcripts were less infectious than the capped transcripts, particularly on Red Kidney bean. The progeny SCNMV particles derived from the transcript infection had infectivity similar to that of the native viral RNA-generated virions. Both the capped and the uncapped transcripts containing an artificial poly(A)61 tail were not infectious.
Two new species, Athelia repetobasidifera and Sistotrema microsporum and one new variety, Grandinia arguta var. sphaerospora are described from Japan. The first fungus is characterized by lacking clamps at septa, having small basidiospores and often producing new basidia by the intrabasidial repetition. The second fungus is distinguishable from the previously described species in having smaller basidia and basidiospores. The third one, a new variety, differs from the type variety primarily in having globose and thick-walled (up to 0.5μm thick) basidiospores.