Observation of π

The observation of hydrogenlike πK atoms, consisting of π^{-}K^{+} or π^{+}K^{-} mesons, is presented. The atoms are produced by 24 GeV/c protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionization) of πK atoms in the same targets yields characteristic πK pairs, called "atomic pairs," with small relative momenta Q in the pair center-of-mass system. The upgraded DIRAC experiment observed 349±62 such atomic πK pairs, corresponding to a signal of 5.6 standard deviations. This is the first statistically significant observation of the strange dimesonic πK atom.

[Two types of territory used by the common shrew Sorex araneus L].

The home range of resident animals is considered as "known territory" including a "foraging region." It has been revealed that the activity of an average animal unit in the "foraging region" could be approximated by normal distribution. Estimation of activity distribution in the "known territory" (beyond the "foraging region") was impeded by means of marking since it might be difficult to detect the frequency of distant translocations, and the method does not provide an essential body of data. In the case of the common shrew Sorex araneus, the "known territory" was estimated using trap cones as animals evade them in the known areal. The "foraging region" radius of the average shrew was taken to be 30 m (95% of the animal unit activity), the radius of known territory was within the range of 180-240 m. The "foraging region" was expected to provide the animal with vital resources, and the "known territory" reflects its need for exploratory activity.

On the correlation of S-S and C-S raman bands frequencies and intensities with conformations of disulfide bridges in proteins.

We have studied dependence of the S-S and C-S raman bands frequencies and intensities on the conformation of disulfide bridges. These correlations have been analyzed on the basis of the normal coordinates treatment in the valence force field and from comparison of the raman and X-ray data for the model compounds and proteins. The found regularity of the intensity variations with conformation make it possible to distinguish these spectral perturbations from those associated with the change in the number of disulfide bridges in proteins. Particularly, this was demonstrated on the gamma-irradiated insulin solutions spectra. We also present some data appropriate for estimation of the content of disulfide bridges in proteins using internal intensity standards.

[Study of calcium binding to calmodulin using laser raman spectroscopy]. / Izuchenie sviazyvania kal'tsiia kal'modulinom metodom lazernoi spektroskopii kombinatsionnogo rasseianiia.

Laser Raman spectroscopy has been used to study calcium binding to calmodulin, Ca2+-dependent regulator protein. Cation binding accompanied by spectral changes of tyrosine residues in the regions of Fermi-resonance doublet and 1600-1620 cm-1, of some carboxylate-containing residues, amide I, III and C-C(N) skeletal vibrations. Amide III contour analysis and calculations of Amide I contours show that complexation causes peptide backbone conformational changes characterized mainly by increased alpha-helical content.