[Reply to the letter-to-the-editors by V.A. Pitkevich, V.K. Ivanov, S.Iu. Chekin, A.F. Tsyb, "Concerning the problem of radiation exposure levels to the Chernobyl AES accident clean-up participants, included in Russian Medical-Dosimetric State Registry"]. / Otvet na pis'mo v Redaktsiiu V.A. Pitkevicha, V.K. Ivanova, S.Iu. Chekina, A.F. Tsyba "K voprosu o luchevykh nagruzkakh na uchastnikov likvidatsii posledstvii avarii na Chernobyl'skoi AES, zanesennykh v Rossiiskii gosudarstvennyi mediko-dozimetricheskii registr".

Theoretical and practical problems related to the dosimetric data verification for recovery workers at the Chernobyl NPP are considered. The distinctions in definitions epsilon-entropy in paper [1] and delta-entropy in [2] are considered. In a certain measure this distinctions explain distinction in conclusions, made in these papers. Method of dosimetric data collection, used by Institute of Biophysics and its difference from the method of data acquisition, used in national Medical-dosimetric registers is described. Results on determination of a share of participants given for various clean-up worker divisions, contained in pointed delta-shape peaks, received by two various methods, stated in [2] and [6], are compared and their satisfactory conformity with one another is established.

[The need to account for beta radiation in determining the total radiation exposure of those working in cleanup]. / O neobkhodimosti ucheta beta-izlucheniia pri opredelenii summarnogo luchevogo vozdeistviia na likvidatorov.

The role of external beta-radiation as one of the major radiation factors effected persons involved in recovery operations (liquidators) after the accident at the Chernobyl nuclear power plant is considered. The paper uses the data of discriminate individual dosimetric monitoring of beta- and gamma-radiation for different groups of liquidators and experimentally received dose distribution in tissue equivalent material in the places of carrying out work. The results obtained by calculation were also used. It was established that experimentally determined ratios of beta-radiation doses to gamma-radiation doses have a good correlation with estimates resulted by calculation. It allowed the authors to use these estimates and individual gamma-radiation dose distribution for drawing histograms of individual beta-radiation dose distribution for open parts of skin, for lens, and gonads in cases of liquidators involved in building "sarcophagus". The obtained estimates of individual doses in the near surface tissue and organs exceeds significantly exposure levels for the whole body. This fact should draw the special attention to the rise in the number of radiation-induced cancer and cataracts.

[The irradiation levels of the participants in the cleanup of the aftermath of the Chernobyl accident in 1986-1987 and the verification of the dosimetric data]. / Urovni oblucheniia uchastnikov likvidatsii posledstvii Chernobyl'skoi avarii v 1986--1987 gg. i verifikatsiia dozimetricheskikh dannykh.

It is considered the organization of individual dosimetric monitoring (IDM) within 30-km zone around Chernobyl nuclear power plant (CNPP) in 1986 for different contingents of recovery workers: the CNPP personnel, Management for Construction 605 (MC-605), military recovery workers, persons assigned to 30-km zone. It is concluded that the quality of IDM had decreased in the following series: the MC-605 personnel, the CNPP personnel, the assigned persons, and military units. The method of dosimetric data verification for recovery workers in 1986 is presented which is based on the analyses of the dependency H(delta)/In delta from delta, where delta is a step of the histogram of distribution, and H(delta) is delta-entropy of distribution. The results obtained by this method correspond to the results of the experts' estimation. It was shown that 60% of registered individual doses for the whole contingent of the recovery workers differ from the real exposure doses. Using the theory of hybrid lognormal distribution it was obtained, in our opinion, real external dose distribution for all the recovery workers. It was estimated that 7% of recovery workers received doses more than 0.25 Gy. Also, the data on values of mean and collective doses for different contingents, as well as for all persons involved in recovery operations is presented.

[Frequency and gradient dispersion of viscosity of dna solutions]. / Chastotnaia i gradientnaia dispersiia viazkosti rastvorov DNK.

Gradual and frequential dispersion of the viscosity of DNA solution in cattle splin was studied. Zimm--Crothers rotational viscosimeter was used for determining gradient relationship of viscosity eta (g). To determine frequential dispersion of viscosity a magnetelecttric vibrational viscosimeter with the working range of 16-100 Hz was produced. It was found that gradient relationship of specific viscosity coincides within the measuring error with the frequential relationship of actual component of specific viscosity at dynamic measurements. The influence of the alternating force with the frequency f is equivalent to the effect of stationary applied force producing the gradient g=k with f, where k=3,2 plus or minus 0,4.