wi severity from each Shot than that at ground sero from s 20 KT atomic bomb detonated «t a 2000~ft. height. The shelter successfully withstood the individusl and cumulative blast overloadings with light to moderate obser~ vable damage. Final evaluation d radiation, pressure and displacement measurements will furnish valuable data for future consideration with respect to gamma radiation, reflected atatic pressures from shock fronts, and dynamic overpressures, or wind drag, inside the shelter and their effects on occupants. | The data obtained from this test will be made available to the FCuA for review amd study, and ita applicability to civil defense practices for protective measures. (End of Confidential) Instrumsnt Loan Program (Unclassified) instruments were provided for FCOA fer use in the three touring exhibits, the "Alert Americas Convoye.* These conwys have been prepared and are operated by the Valley forge Foundation for FCDA. Effect of <-radiation on Chromosome Breakare. Recent studies at Brockhaven include the effecta of X-radiation on various plants. In experinenting with a lily, as a typical plant, an interesting reaction was noticed. Chromosome fragnentation oceurs most frequently if the radiation is clven when the dividing cells are at the diplotens stage, immediately preceding the actual division of the cell nucleus. It nas been found that mucleic acid (DMA) is actively synthesized up to that time, and then remains constant. Thus it is believed that chromosome breakage, or mutation, 1s associated with DHA synthesis, even though this is not the only factor in radiosensitivity. Protective chemicals to living cells. The protective action of certain chemicale againat irradiation damage to living ceils continues to be a subject of aajor interest at ORNL. High oxyzen concentration ia directly related to death by I-irradlation, and most ghenicals which give increased orotection against radiation damage are oxidigable compounds. Hecant work has shown how this protective action results. It is showm that these protective chemicals remove oxygen from within and around bacterial cells, and this decreases the concentration of toxic substances formed by the action of X-rays, Radiation Instruments Catalog, Preparation of the 1952 edition of the Radiation Instruments Catalog has been initiated. The new issue will be about one tiird the present size and will represent a considerable savings in publication costs and an improvement in format. 16—-63110-1 OFFICE . SURNAME > DATE >» oro