-. : te mt she a . woe . woo Be . a a cu ae . . . fe LL So erga. a Le ae 7 Be 4, ot . eR CRISS:eeeaes ansote SAAS | ae Sas RecentstudiesatBrookhares:-include'‘the: effects:of:X-redi: fon¢ on various “plants?a9In:experimenting with’,a:Tily, ‘as:a‘typical plant; oe a we interesting reaction was noticed.’ to frequently if the radiation is given when the dividing cells. are diplotene stage, immediately preceding the actual division of the nucleus. It has teen found that nucleic acid (DNA) is actively sypthesized up to that time, and then remains constant. Thus it is belikved that chromosome breakage, or mutation, is associated with DNA synthesis, even though this is not the only factor in radiosensitivity. Protective Chemicals to Living Cells - The protective action of certain chemicals against irradiat -Orl damage to living cells continues to be a subject of major interest at ORNL. High oxygen concentration is directly related to death by X firradiation, and most chemicals which give increased protection agains | radiation damage are oxidizable compounds. Recent work has shown how t is protective action results. It is shown that these protective chem icals remove oxygen from within and around bacterial cells, and this dec feases the concentration of toxic substances formed by the action of X-raTs. Radiation Instruments Catalog Preparation of the 1952 edition of the Radiation Instrument Catalog has been initiated. The new issue will be about one-third the present size and will represent a considerable savings in publicat; on costs and an improvement in format. Ra-Det . The Novenber issue of Ra-Det will include as its feature arficles, a report on a tritium air monitor developed at Los Alamos Scientif Laboratory, and a progress report on the development of the specia§ photomultiplier tubes at RCA Laboratories under AEC contract. well Both of these items have been of interest to AEC personnel as to other governmental agencies, and the articles provide considdrable factual data. Visitors to Radiation Instruments Branch In November, the RIB received 15 visitors from the following organizations: Ericson Research Laboratory, Radio Corporation of 4 merica Research Laboratory, Westinghouse Atomic Energy Laboratory, H1-Tror LCS, Inc., Beckman Instruments, Inc., Nuclear Instruments and Chemical Q or poration, Landsverk Electrometer Company, Office of Naval Research, Nav iy Department Bureau of Aeronautics, Bureau of Standards. 5! Princeton University, ——— and the Nat honal DOE agcHivEs eeeo 2 nae ierie ee . op ete

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