We developed a radiographic technique to image a subsurface conduit shape using cosmic‐ray muons. The test measurement was performed in Showa‐Shinzan lava dome located in Hokkaido, Japan as an example. A muon detector with an area of 6000 cm2 was set up at the foot of the lava dome. Muon tracks recorded in nuclear emulsion films in the detector were analyzed to determine the level of energy absorption along different ray paths through subsurface beneath the lava dome. A typical angular resolution of the muon detector of 10 mrad corresponds to a spatial resolution of 10 m at a distance of 1 km, which is difficult to be addressed with seismological technique. We mapped differentially absorbed cosmic‐ray muons, which depend upon the varying thickness and density beneath the dome. We successfully imaged the conduit shape and determined a conduit diameter of 102 ± 15 m, assuming the observed high absorption region beneath the dome is localized in the vent area.

Invasion of two PNA strands to double-stranded DNA is one of the most promising methods to recognize a predetermined site in double-stranded DNA (PNA = peptide nucleic acid). In order to facilitate this ‘double-duplex invasion’, a new type of PNA was prepared by using chiral PNA monomers in which a nucleobase was bound to the α-nitrogen of N-(2-aminoethyl)-d-lysine. These positively charged monomer units, introduced to defined positions in Nielsen's PNAs (poly[N-(2-aminoethyl)glycine] derivatives), promoted the invasion without impairing mismatch-recognizing activity. When pseudo-complementary nucleobases 2,6-diaminopurine and 2-thiouracil were bound to N-(2-aminoethyl)-d-lysine, the invasion successfully occurred even at highly G–C-rich regions [e.g. (G/C)7(A/T)3 and (G/C)8(A/T)2] which were otherwise hardly targeted. Thus, the scope of sequences available as the target site has been greatly expanded. In contrast with the promotion by the chiral PNA monomers derived from N-(2-aminoethyl)-d-lysine, their l-isomers hardly invaded, showing crucial importance of the d-chirality. The promotion of double-duplex invasion by the chiral (d) PNA monomer units was ascribed to both destabilization of PNA/PNA duplex and stabilization of PNA/DNA duplexes.

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In the DsTau experiment at the CERN SPS, an independent and direct way to measure tau neutrino production following high energy proton interactions was proposed. As the main source of tau neutrinos is a decay of D s mesons, produced in proton-nucleus interactions, the project aims at measuring a differential cross section of this reaction. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here we present the motivation of the study, details of the experimental technique, and the first results of the analysis of the data collected during test runs, which prove feasibility of the full scale study of the process in future.