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[en] Complete text of publication follows. Dentistry students were assessed in one of the school of dentistry in Iran. 11% of responders had attended a radiation protection course. This study showed that those who have attended this course had improved knowledge of ALARA principle, assessment of the impact of digital imaging in patient dose reduction and usage of personal dosimeter systems. Course attendance made no considerable difference to knowledge of the patient dose, dose reduction techniques and annual permissible dose limits of general public and radiation workers. The results of this study revealed that the majority of students have not received adequate radiation protection teaching and even if a course has been attended, overall knowledge is still poor and formal teaching at undergraduate level should be corrected in the future.
[en] On the behalf of the Organising Committee, the International Journal of Low Radiation, the Hungarian Biophysical Society and the 'Frederic Joliot-Curie' National Research Institute for Radiobiology and Radiohygiene has been held the 6th International Conference on Low Dose Radiation Effects on Human Health and Environment (LOWRAD2007). LOWRAD2007 in Budapest, Hungary through October 18-20, 2007. The main topics was low radiation effect in the area of the radiology and nuclear medicine, radiation protection, dosimetry, environmental issues and waste management etc. One of the major goals of LOWRAD2007 is to encourage international cooperation and communication in all fields of low dose radiation science. This meeting provided a forum for the exchange of scientific ideas for all scientists of various countries. All aspects of low dose radiation research has been included in the scientific program. The program contained educational lectures to facilitate contacts between young and established scientists. (S.I.)
[en] Complete text of publication follows. Autoradiography was done in monitoring the kinetics of spermatocytes labeled from their 'S' period with a view to estimating the duration of individual stages of meiosis and spermiogenesis in a large number of vertebrates from Fish to Mammals since 1970's during our research work in other University and the Genetics Laboratory, University of Burdwan, West Bengal. A pilot study was engineered by injecting intraperitoneally, or intratesticularly, or even directly into blood vessels in any vertebrate without any distinction of mammal or non-mammal, 05 μ Ci of 3H TDR (Sp. Act. 14600 m ci/mM, BARC, Trombay). Exclusive studies had been made using isotopes at the level of Karyotypes and individual chromosomes were identified through autoradiography, Banding and Fluorescence microscopy but no chromosomal aberration has been noticed.
[en] Complete text of publication follows. The results of measurements of Cs-137 in soil profiles which were sampled in undisturbed soil in Ondo, Ekiti and Oyo states in the southwestern area of Nigeria are presented in this paper. Samples were collected from nine soil profiles. The vertical distribution of Cs- 137 in the soil profiles have been determined. Caesium concentration ranged from 0.31 ± 0.10 Bqkg-1 in the 0-2 cm depth to a maximum of 1.25 ± 0.21 Bqkg-1 in the 6-8 cm depth at some sites and from 3.16 ± 0.16 Bqkg-1 in 0-5 cm depth to below detection limit (BDL) at 20-25 cm at another site. The results generally show that fifteen years after the Chernobyl accident and more than 40 years after the nuclear probes, Cs-137 still remains within 25 cm of upper layer of soil in the region and its penetration in the soils is a very slow process. The mean value of effective dose commitment due to the presence of caesium in soil in the entire region was found to be 10.77μSv.
[en] Complete text of publication follows. The main goal of this work was to study in Drosophila melanogaster the contribution of DNA damage sensing and repair, apoptosis and heat shock defence into life span and physical activity alteration after gamma-irradiation at low doze rate. In our experiments, the strains were exposed to chronic gamma-irradiation from a 226Ra source (50 R/h) at doze rate 0.17 cGy/h at pre-imago development stages only. The absorbed radiation dose per generation (from embryo to imago, 12 days) was 60 cGy. Life span estimation was prepared in adult males and females separately. We compared the life span of apoptotic (p53, DIAP-1, dApaf-1, Dcp-1, reaper, grim and hid), heat shock defence (HSP70, HSP23, HSF), DNA damage sensing (ATR) and repair (XPF, XPC, PCNA, DSB repair helicase homologs) mutants after chronic irradiation with the control. On the basis of our investigation we have concluded: 1) Low doze irradiation alter the life span depending on genetic background (mutant alleles, heterozygosity level and sex); 2) Age dynamics of physical activity positively correlates with the life span; 3) Longevity potential forms at early development stages; 4) DNA damage sensing, DNA repair, heat shock defence and apoptosis as aging preventing mechanisms play crucial role in radiation-induced life span hormesis.
[en] Complete text of publication follows. Non-photochemical quenching (NPQ) of chlorophyll fluorescence has been known to be involved in a protection of photosystems against photoinhibition through a dissipation of excess light absorbed by photosynthetic pigments. In the present study, we aimed to elucidate the effects of a ionizing radiation on NPQ by comparing alterations in the development and release of NPQ after gamma-irradiation between the wild-type (WT) and the npq1-2 mutant of Arabidopsis. The npq1-2 mutant can't develop with a normal NPQ under excess light, since it is defective in its de-epoxidase activity for conversion of violaxanthin to zeaxanthin. Gamma-irradiation with a dose of 200 Gy inhibited the development of NPQ in both the WT and mutant but more noticeably in the latter. Moreover, Fv/Fm as an indice of the photochemical efficiency of photosystem II (PSII) was almost the same in both the WT and npq1-2 mutant throughout the post-irradiation period of 5 d. The obtained results will be also discussed with those from photoinhibition induced by non-ionizing radiations such as visible light and UV-B.
[en] Complete text of publication follows. Background: A certain level of background exposure to ionizing radiation and natural or man-made chemicals is always present in the environment. Radon and its short-lived decay products are considered as important sources of public exposure to the natural radioactivity. It is well known from epidemiological and toxicological studies that synergistic interaction between smoking and radon occurs, which is especially important for high natural background areas. Objective: This study has been done to suggest a mathematical model to describe the synergistic interaction of radon with tobacco smoking, and to demonstrate the ability of the model to describe carcinogenic effects of the combined action. Methods: A simple mathematical model was formulated to describe and predict the synergistic interaction of radon with smoking. The model postulates that the occurrence of synergism is to be expected as a result of additional carcinogenic damage arisen from the interaction of sublesions induced by the two factors under consideration. Results: The predictions of the model were verified by comparison with experimental data published by other researchers. The model appears to be appropriate and the predictions are valid. Conclusions: : The suggested mathematical model predicts the greatest level of synergistic effect and condition under which the maximum synergy is attained. The synergistic effect appeared to decline with any deviation from the optimal value of the ratio of carcinogenic effective damages produced by each agent alone.
[en] Complete text of publication follows. Ionizing radiation causes many alterations in photosynthetic machineries. However, there is no information about effects of ionizing radiation on the development of photosynthetic machineries in plants. We investigated the greening of etiolated mung bean seedlings irradiated with gamma rays of 50 to 300 Gy. The gamma-irradiation inhibited seedling growth with great dependence on the radiation dose. In particular, growth of stems was more affected than that of hypocotyls. Irradiated leaves showed inhibition in growth, aberration in morphology, and yellowing in color depending on the radiation dose. Pigment analysis indicated that contents of chlorophylls and carotenoids were significantly decreased in the irradiated leaves. The maximal electron transport rate of photosynthesis was also decreased in the irradiated leaves except the 50-Gy samples. However, the maximal photochemical efficiency was little affected by the irradiation. These results may imply that the overall photosynthetic machineries can develop and work to some extent as a concerted system for photosynthesis after exposure to acute doses of ionizing radiation.
[en] Complete text of publication follows. Genomic Instability (GI) is defined as long-term alterations induced by low-dose exposure to a variety of genotoxic agents in mammalian cells that act to increase the 'apparent' spontaneous mutation frequency.GI is a hallmark of tumorigenic progression and is observed in the progeny of irradiated and bystander cells as the delayed and stochastic appearance of de novo chromosomal aberrations, gene mutations and delayed lethal mutations both in vitro and in vivo. It occurs at a frequency several orders of magnitude greater than would be expected for mutation in a single gene, implying that GI is a multigenic phenomenon. The expression of GI can be influenced by genotype, cell type and radiation quality; however the underlying mechanisms are not fully understood. While several studies have demonstrated GI induction by high and low LET radiation, our work on human and mouse primary cell systems has shown significant differences in the capacity to induce GI and the spectrum of alterations depending on LET. These differences might be attributed to differences in radiation track structure, radiation dose and radiation exposure regime (distribution of hit and un hit cells). In this presentation I shall review the role of radiation quality; describe the possible mechanisms underlining the observed differences between radiation type and present results of experiments demonstrating that the dose of low LET radiation might be the most significant factor in determining the role of radiation type in the induction of GI.
[en] Complete text of publication follows. All ionising radiation interacts in the form of highly structured tracks of ionizations and excitations which vary significantly with radiation quality. Energy deposition is highly inhomogeneous and this becomes more apparent the smaller the target volume and especially at lower doses and dose rates. The spatial and temporal distribution of these events are important in determining the resultant biological response. Current risk assessments are based on acute high dose exposures, however typical human exposures are associated with much lower doses and dose rates with many individual cells unlikely to experience more than one track over long time periods of months to years, with many cells unirradiated over this period. Biological responses are not only observed in irradiated cells but also non-exposed neighbouring cells as a result of inter-cellular signalling and this potentially has important implications on the estimates of risk for low dose and low dose rate exposures. The relevance of radiation tracks structure a low dose and dose rates will be discussed along with recent experimental results, including data showing that doses as low as 2 mGy ?-rays and 0.3 mGy γ-particles to a cell population were sufficient to produce an observable increase in apoptosis in unirradiated transformed cells co-cultured with the irradiated cells.