No abstract available

[en] The lethal potentially lethal (LPL) model is used to study the low dose rate problem. During irradiation, it is assumed that lesions are being created, repaired, and misrepaired. Two differential equations are used to describe the variations of the rates of production with time of potentially lethal (n/sub B/) and lethal (n/sub C/) lesions, respectively

[en] This report summarizes a simulation of the short-term effects of a limited nuclear exchange in Europe. The number of fatalities due to the blast and thermal effects was found to be 7.4 million. The total casualties from these effects (deaths plus injuries) amounted to 15.6 million. In summary the simulation of a very limited nuclear exchange in Europe - against military targets only and using less than 1% of existing nuclear arsenals - has shown that it could result in the death or injury of more than 100 million people; a catastrophe of unimaginable dimension. 7 refs, 6 figs, 2 tabs

[en] Considerable information is available on the effects of radioactivity on adult and early life stages of organisms. The preponderance of data is on mortality after a single irradiation with relatively high doses. Unfortunately, because experiments were carried out under different conditions and for different time periods, the validity of comparing the results from different taxonomic groups is questionable. In general, the conclusions are that there is a relationship (1) between radioresistance to high doses of acute radiation and taxonomy of the organism, primitive forms being more radioresistant than complex vertebrates and (2) between radiosensitivity and developmental stage, early life stages being more sensitive than later stages. The first conclusion may be related to the capability of the organism to repopulate cells and to dedifferentiate and redifferentiate them; the second to the rate of cellular division and to the degree of differentiation. In question, however, is the relevance of the responses from high levels of acute radiation to that of the responses to long-term exposure to low levels of radiation, which are ecologically of more interest. Data from studies of the effects of acute and chronic exposure on development of gametes and zygotes indicate that, for some fishes and invertebrates, responses at the cellular and molecular levels show effect levels comparable to those observed in some mammals. Acute doses between 0.05 and 0.5 Gy and dose rates between 0.02 to 0.2 mGy/h appear to define critical ranges in which detrimental effects on fertility are first observed in a variety of radiosensitive organisms. To better understand inherent radiosensitivity, we need more information on the ability of cells to repopulate and differentiate and to prevent or repair damage to biological critical molecules, such as DNA, because these factors may alter significantly organisms' responses to radiation

[en] The evaluation of the risk of a terrorist attack has been made frequently by multiplying the probability of occurrence of a terrorist attempt by the probability of its success and a quantity which represents the consequences of a successful attack. In the case of a radiological attack the consequences will vary in case the action will be active or passive. Thirteen radionuclides were examined for their potential uses in credible threats or terrorist attacks based on their availability from laboratories and hospitals. Taking into account the dose conversion coefficients published by the International Atomic Energy Agency, those radionuclides with higher dose effectiveness for ingestion are the following: "2"1"0Po; "2"2"6Ra and "2"4"1Am. Other radionuclides which can be used in threats and terror attacks, like "1"3"7Cs for example have also been examined. The risks associated with the selected radionuclides have been tentatively ranked as high, medium, or low. The probability used to evaluate risks depends on the motivation of the terrorist and the capacity, which implies availability or the actual possibility of obtaining a particular radionuclide. On the other hand, whenever a list of radionuclides to be used in a malevolent action is available to a terrorist, the choice of the most adequate will depend also on the action to be undertaken. This work ranks risks associated with radiological terror based on physical, chemical, radio-toxicological and other relevant data on radionuclides, which were either already used in terror attacks, or were pointed out as adequate to be used in such malevolent actions. (author)

[en] The work on improvement of mungbean and blackgram was initiated by treating the seeds of local cultivars with different doses of gamma rays (5-80 krad). Radiosensitivity studies in M₁ and frequency of chlorophyll mutations in M₂ for both species indicated 30 krad of gamma rays as being an appropriate dose for plant breeding purpose: lethal dose 50 (LD₅₀) lies somewhere around 60 krad. After the release of mutant variety NIAB Mung (NM)-28 in 1983, efforts led to the development of several high yielding and early maturing mutants in mungbean. Of these, four mutants, NM121-25, NM19-19, NM20-21 and NM13-1, were released as commercial varieties in 1986. These mutant varieties yield 30-45% higher than the parents, mature in 55-70 days and are suited to both the spring and summer crop seasons. Mutants NM20-21 and NM13-1 also fit very well to take an extra crop in the fallow period between wheat harvest and rice/maize plantation. Efforts to incorporate large seeded character from exotic varieties in local small seeded cultivars/mutants through hybridization and radiation of hybrid seeds resulted in the development of several large seeded, high yielding and disease resistant recombinants which thrive in both the spring and summer. In blackgram, several high yielding mutants having early maturity and upright growth habit were induced in local cultivars. Some of them mature two to three weeks early and have yields 40-50% higher than the parental types. Several mutants with increased seed size and changes in seed coat colour were also identified. The genetic behaviour of some of the induced mutants is reported. (author). 14 tabs

[en] Our recent work in the comparison of parametric models for use in animal radiation mortality studies is reviewed, along with predictions of lethal doses for man based on these models. 1 ref., 1 tab

[en] The threat of male infertility became a big issue for the human population as modern technologies emerged as a source of radiofrequency radiation (RFR) and studies have shown that these radiations are lethal for human health. These technologies have become an essential part of our everyday life. Therefore, it is necessary to find its effects on reproduction. The current study concentrated on the biological consequences of electromagnetic radiation exposure on mouse Leydig (TM3) cell in a time-dependent way. The cells were subjected to 2.45 GHz non-ionizing electromagnetic radiation in the exposure system at various time intervals (15, 30, 45, 60, 90, and 120 minutes), and cell were assessed for viability, apoptosis, ROS, and testosterone levels. Cell viability was not significantly (p<0.05) affected by EMF exposure via the Exposure system. In the irradiated group, there was a significant increase in apoptotic cells as compared to the control group. At 60, 90, and 120 minutes, the irradiation group had significantly lower testosterone levels than the control group. At all of the time periods following irradiation through exposure system, the levels of ROS did not significantly alter. In conclusion, the current study shows that exposure to radiofrequency electromagnetic radiation emitted from exposure systems can cause adverse effects on the male fertility by impairing Leydig cell (TM3) function, like decreased testosterone production and increased cell apoptosis. (author)

[en] For several years some cosmetic raw materials and finished products have been successfully treated with irradiation to control microbial growth. Basic studies have been initiated to test the successful application of irradiation to a raw material or finished product in the cosmetics industry. Acceptance of this technology by industry and by regulatory agencies, is dependent upon the correct application of the technology and documenting the results of carefully controlled studies. A short list of raw materials was selected on which the immediate test work was undertaken. It includes talc, starch, gelatin and bentonite. This will increase confidence and expertise in this technology. (author)

[en] The ''low dose'' and/or ''high dose'' of ionizing radiation are common terms widely used in radiation applications, radiation protection and radiobiology, and natural radiation environment. Reading the title, the papers of this interesting and highly important conference and the related literature, one can simply raise the question; ''What are the levels and/or criteria for defining a low dose or a high dose of ionizing radiation?''. This is due to the fact that the criteria for these terms and for dose levels between these two extreme quantities have not yet been set, so that the terms relatively lower doses or higher doses are usually applied. Therefore, setting criteria for classification of radiation doses in the above mentioned areas seems a vital need. The author while realizing the existing problems to achieve this important task, has made efforts in this paper to justify this need and has proposed some criteria, in particular for the classification of natural radiation areas, based on a system of dose limitation. (author)