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M Beno

Publications and source records attributed to M Beno.

14 recordsLinked to original sources
PubMed1995

Additivity test for composition of binomial effects in chromosome aberrations after radiation injury.

Additivity of clastogenic effects of two doses of radiation to human peripheral blood lymphocytes is considered. We compare the effects of combined tritium and gamma irradiation with the sum of the effects of either irradiation administered separately. Our solution is based on combination of de Moivre and Cramèr-Slucky theorems. The results for 14 subjects where the deletion types of chromosome aberrations were counted indicate a Normal distribution of the sample additivity index, oscillating non-significantly around zero, with one outlier towards adaptivity and another towards synergism of the effect of the two doses absorbed by the cells.

Adult↗
PubMed1992

Transfer factor of 131I from the fallout to human thyroid dose equivalent after the Chernobyl accident.

A similar pattern of variation with time in observed maxima of daily dose equivalent rates in human thyroids (TD - microSv.d-1) and of daily fallout radioactivities (FR - kBq.m-2) has been found after the Chernobyl accident. An estimate of the time-lag between the maxima in TD lines and the preceding FR peaks was made of about seven days for adult and nine days for juveniles. Applying this time-lag it was possible to estimate transfer factors from the fallout to thyroid dose equivalent: the highest estimated values were 221 microSv/kBq.m-2 for adult and 641 microSv/kBq.m-2 for juvenile thyroids. These values differ from those published by UNSCEAR (United Nations 1988), which have been calculated for various regions of Czechoslovakia, from ingestion and inhalation intake estimates. A broad variation of transfer factor values could be expected to result from such transfer calculations using ingestion and inhalation estimates. The findings also support the concept of a need for prolonged iodine prophylaxy after emissions of radioiodine into the environment.

Accidents↗
PubMed1991

Human postmortem thyroid 131I content and risk estimates in Bratislava, Czechoslovakia following the Chernobyl accident.

From 3 May to 4 August 1986, thyroids of 416 postmortem subjects in Bratislava (population: approximately 400,000) were measured for 131I. Subsequently, dose rates in this organ for the day of exitus were calculated. Mean dose commitments were estimated by integrating linear or quadratic-periodic regression lines drawn through scatterplots of logarithmically transformed daily dose rates. The mean dose-commitment estimates in thyroids of adults were 0.74 and 0.58 mGy for linear and quadratic-periodic regression, respectively. The same for thyroids obtained from donors of fetal to 18 y of age were 1.67 and 1.77 mGy for liner and quadratic-periodic regression, respectively. A comparison of the actual thyroid radiation burden with its theoretical values calculated in the first days of contamination of the environment showed that the models used were safe enough to protect the population. Estimates of absolute risk for thyroid cancer showed that excess incidence that could be expected as a result of the Chernobyl accident shall remain obscured by the "spontaneous" incidence of this disease at geographic localization.

Accidents↗