Current Status and Prospects of Bioassay

The status of bioassay, which is a relatively new method in analytical chemistry, is discussed. This method is of paramount importance for environmental analysis. Attention is focused on the combined effects of analytes on indicator organisms.     

Biological methods of analysis

Biological methods of analysis, which use whole organisms or parts of organisms as analytical indicators, have the advantages of great selectivity and sensitivity. They are particularly well suited to environmental analysis.     

Unique determination of the constants of ABC and ABCD NMR spectra

A system of equations is derived to relate the constants of NMR spectra of ABCD type to the observed energies; it is shown that one can use the spectra from a substance recorded at three different working frequencies to determine unambiguously the values for the constants. Only two frequencies are required to solve the analogous problem for an ABC system.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 17–20, February, 1974.     

Further evidence for formation of a narrow baryon resonance with positive strangeness in K + collisions with Xe nuclei

We have continued our investigation of the charge-exchange reaction K ⁺Xe → K ⁰ pXe’ in the bubble chamber DIANA. In agreement with our previous results based on part of the present statistics, formation of a narrow pK ⁰ resonance with mass of 1537 ± 2 MeV/c ² is observed in the elementary transition K ⁺ n → K ⁰ p on a neutron bound in the xenon nucleus. The visible width of the peak is consistent with being entirely due to instrumental resolution and allows one to place an upper limit on its intrinsic width: Γ < 9 MeV/c ². A more precise estimate of the resonance intrinsic width, Γ = 0.36 ± 0.11 MeV/c ², is obtained from the ratio between the numbers of resonant and nonresonant charge-exchange events. The signal is observed in a restricted interval of incident K ⁺ momentum that is consistent with smearing of a narrow pK ⁰ resonance by Fermi motion of the target neutron. The statistical significance of the signal is some 7.3, 5.3, and 4.3 standard deviations for the estimators and , respectively. This observation confirms and reinforces our earlier results, and offers strong evidence for formation of a pentaquark baryon with positive strangeness in the charge-exchange reaction K ⁺ n → K ⁰ p on a bound neutron. (The DIANA Collaboration) The text was submitted by the authors in English.     

ΔE-E detector for proton registration in nonmesonic deuteron breakup at the Nuclotron internal target

A design for a ΔE-E detector to investigate deuteron breakup in the Nuclotron-M internal target in a deuteron energy interval of 300–500 MeV is presented. The high-voltage power supply system of the PMT-63, which is based on the computer-controlled Wenzel Electronik module, is briefly described. A light-emitting diode (LED) monitoring system for the ΔE-E detector is considered. The results of testing the ΔE-E detector using cosmic muons and deuteron beams of the Nuclotron are presented.