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Summary This study suggested that cell-cycle kinetics, DNA replication and DNA repair react to magnetic fields differently. During
their culture growth cycle, which lasted about five days, Friend erythroleukemia cells were either kept in the absence of
magnetic fields in a magnetically shielded room or irradiated in a solenoid with 70 μT at 50 Hz plus 45 μT DC of the Earth:
some cells grew without inducer of in vitro differentiation; others were induced to differentiate hemoglobin through dimethylsulfoxide. It emerged that, during a single
culture growth cycle, while proliferation was slightly accelerated by the magnetic-field irradiation achieved in the solenoid
both in undifferentiating and dimethylsulfoxide-differentiating cells, DNA replication did not appear to significantly depend
on the magnetic-field deprivation achieved in the magnetically shielded room. However, as a result of a 318-day long magnetic-field
irradiation in the solenoid, DNA replication remained unchanged in undifferentiating cells and partially inhibited in dimethylsulfoxide-differentiating
cells. Following the same long magnetic-field irradiation in the solenoid, the amount of labelled repair patches in the parental
DNA strands was slightly reduced. 相似文献
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ObjectivesTo examine the causes associated with high risk helicopter operations, in particular external load and aerial application flight, and determine the role of crew management in accident mitigation strategies.MethodsData from the US National Transportation Safety Board online database were analyzed. Flight phases and types of rotor strike were added categories extracted from the narrative statements included in the accident reports.Results and recommendationsAerial application and external load accidents are characterized by high numbers of rollovers, rotor strikes and errors during preflight checks. Additional flight or ground crew may assist the pilot in maintaining a visual lookout. The number of accidents can be further reduced with adequate fuel management in which both pilot and ground crew can contribute. Although the ground crew can be both victim and cause of an accident, their supporting role has much to contribute to safety in high risk helicopter operations. 相似文献
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