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Purpose: To investigate cytogenetic and mutational eÚects in lymphocytes from individuals chronically exposed to radiation from the Chernobyl catastrophe. Materials and methods: Nine years after the Chernobyl accident (1986), peripheral blood lymphocytes from 20 Kalinkovichi children (age 10-15) and 10 Minsk children (age 10-17) were analysed for genetic damage by several assays. Radiation damage in exposed children was investigated in descendants of progenitor cells that were irradiated during a short period immediately after the accident. In the time-span between the accident and blood sampling the cells were also irradiated chronically by internal radiation originating from ingested radionuclides and, to a smaller extent, by external radiation from radionuclides. The parameters measured in whole blood smears were the frequency of micronucleated mononucleated lymphocytes and binucleated lymphocytes with nucleoplasmic bridges and associated micronuclei. Cultures of cytokinesis-blocked lymphocytes were used to analyse mononuclear and binuclear cells for the presence of micronuclei, also cell killing effects. A colony assay was used to study induction of recessive mutations in the HPRT gene. Results: The analysis of whole-blood smears indicated a doubling of the frequency of micronuclei per 100 mononuclear lymphocytes in exposed children compared with unirradiated children. Small numbers of binucleated lymphocytes with nucleoplasmic bridges and associated micronuclei were found in blood smears from exposed children. Analysis of cytokinesis-blocked cultures indicated in mononuclear cells of exposed children a statistically significant increase in the frequency of micronuclei. When the same parameters were studied in binucleated cells there was no difference between exposed and unexposed children. Results of the dye-exclusion assay showed a four-fold increase in the percentage of dead cells between exposed and unexposed children. There was no evidence for induction of HPRT mutations in exposed children. Conclusion: These results indicate that the frequently advocated procedure of simply analysing micronuclei in cytokinesis-blocked binucleated lymphocytes can result in an underestimate of genetic damage induced by radiation accidents. Biodosimetric studies should therefore employ a battery of assays for the detection of several types of genetic damage in different generations of lymphocytes. [ABSTRACT FROM AUTHOR]

Research on life events, social support and depressive behaviour has evolved from the descriptive level to the contextual perspective. Precise conceptualization of the terms used, such as ‘life events’ and ‘social support’ is called for, together with a conscientious application of research techniques like the interview method. Careful analysis of different variables such as ‘provoking agent’ and ‘vulnerability factor’ would seem necessary, before the causality question can be approached. [ABSTRACT FROM AUTHOR]

We explore an under-appreciated side effect of semi-closed greenhouses: the ability to recover transpired water, thereby increasing water use efficiency. Semi-closed greenhouses are fit with cooling equipment, to limit natural ventilation requirements for temperature and humidity control. We assess the effect of cooling system capacity on ventilation needs of semi-closed greenhouses under different climate conditions and provide a general framework to evaluate potential water savings using the semi-closed greenhouse concept in different regions. We simulate greenhouse climate and crop yields for various cooling system capacities in Central Europe (The Netherlands) and Mediterranean (Greece and Algeria) by implementing a “cooling module” into an existing greenhouse model (KASPRO) and validating it using concurrent experimental data. Increasing the capacity of the cooling system has a double effect on water use efficiency (WUE): increase of fruit yield due to improved microclimate and lower water use, due to collection and reuse of vapour condensed in the heat exchanger and, to a lesser extent, lower crop transpiration. Thus WUE is strongly associated to the capacity of the cooling system. Finally, we show that there is a unique relationship between water use efficiency and the coupling of greenhouse environment to the outside air (an indicator of ventilation requirements), for all regions studied. [ABSTRACT FROM AUTHOR]