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The Distribution of Radioactivity in the Mouse Following Administration of Dibenzanthracene Labeled in the 9 and 10 Positions with Carbon Fourteen (open access)

The Distribution of Radioactivity in the Mouse Following Administration of Dibenzanthracene Labeled in the 9 and 10 Positions with Carbon Fourteen

Dibenzanthracene, labeled in the 9 and 10 positions with carbon fourteen has been administered to mice intravenously and by stomach tube as an aqueous colloid, and intraperitoneally, subcutaneously, and by stomach tube in tricaprylin solution. The distribution of radioactivity in the mice at various time intervals after administration of the carcinogen has been determined. The radioactivity is rapidly eliminated, largely through the feces, and ordinarily very little is absorbed. The distribution and rate of elimination depends upon the mode of administration. There is an appreciable quantity of radioactivity in tumors produced several months after a single subcutaneous injection of dibenzanthracene. There appear to be no detectable effects from the radiation of the labeled carcinogen.
Date: January 30, 1948
Creator: Heidelberger, Charles & Jones, Hardin, B.
System: The UNT Digital Library
Stars in Photographic Emulsions Initiated by Deuterons Part II. Theoretical (open access)

Stars in Photographic Emulsions Initiated by Deuterons Part II. Theoretical

The theory of high energy nuclear stars depends on a theory of nuclear transparency and on a theory of nuclear evaporation. The transparency can be computed on the basis of a model proposed by R. Serber as soon as the interactions between the nucleons and the incident particle are known. The evaporation can be computed on the basis of the statistical model of the nucleus as soon as the nuclear entropy and binding energies of the evaporated particles are known. The calculations have been formulated with approximate values for the above interactions, entropies, and binding energies; and by means of various mathematical methods: a method of averages, a method of reaction integrals, and one using diffusion equations. Probability distributions have been obtained for the number of prongs per star, and distributions are being computed for the energy and angle of a prong. The results are in qualitative agreement with the observations on photographic emulsions described in Part I.
Date: January 1, 1948
Creator: Horning, Wendell & Baumhoff, L.
System: The UNT Digital Library
Degradation of Isotopic Lactate and Acetate (open access)

Degradation of Isotopic Lactate and Acetate

A scheme of glucose degradation has been validated by the use of intermediates of known isotopic composition. In this scheme: glucose {yields} lactic acid {yields} CO{sub 2} (C-3,4) + acetic acid {yields} CO{sub 2} (C-2,5) + acetone {yields} iodoform (C-1,6) + acetate (C-1,6; 2,5), it was found that (a) in the oxidation of lactic acid, approximately 4.7% of the acetic acid was oxidized to CO{sub 2}; and (b) under the conditions prescribed, BaCO{sub 3} from the degradation of Ba acetate contained approximately 1.5% of the activity of the methyl group.
Date: February 24, 1948
Creator: Aronoff, S.; Haas, V. A. & Fries, B. A.
System: The UNT Digital Library
Nuclear Reactions of Arsenic with 190 Mev Deuterons (open access)

Nuclear Reactions of Arsenic with 190 Mev Deuterons

Isotopes formed in the bombardment of {sub 33}As{sup 75} with 190 Mev deuterons range in atomic number up to 24 (or more) mass units lighter than As{sup 75}. Identification of these isotopes was based on chemical behavior and half-life determination. Relative yields have been calculated and show that 80% of the observed reactions produce isotopes within 8 mass units of As{sup 75}. Three new isotopes have been observed: 9.5 d. Se{sup 72} (K), 44 m, Se{sup 71} ({beta}{sup +}), and 52 m, As{sup 71} ({beta}{sup +}).
Date: January 21, 1948
Creator: Hopkins Jr, H.H. & Cunningham, B.B.
System: The UNT Digital Library
The Formation of U232 by Helium Ions of Thorium (open access)

The Formation of U232 by Helium Ions of Thorium

The production of U{sup 232} by the sum of {alpha},4n and {alpha},p 3n reactions on thorium has been studied. The cross section at an average energy of 37.5 Mev was 0.013 barns and the threshold for the reaction was about 30 Mev.
Date: April 14, 1948
Creator: Newton, Amos S.
System: The UNT Digital Library
The Fission of Thorium with Alpha Particles (open access)

The Fission of Thorium with Alpha Particles

The fission distribution of fission of thorium with alpha particle of average energy 37.5 Mev has been measured by the chemical method. The distribution found shows that the characteristic dip in the fission yield mass spectrum has been raised to within a factor of two of the peaks compared to a factor of 600 in slow neutron fission of U{sup 235}. The raise in the deip has caused a corresponding lowering in fission yield of these elements at the peaks. The cross section for fission of thorium with 37.5 Mev alphas was found to be about 0.6 barn, and the threshold for fission was found to be 23 to 24 Mev.
Date: April 15, 1948
Creator: Newton, Amos S.
System: The UNT Digital Library
Production of Mesons by the 184-inch Berkeley Cyclotron (open access)

Production of Mesons by the 184-inch Berkeley Cyclotron

The authors have observed tracks which they believe to be due to mesons in photographic plates placed near a target bombarded by 380 Mev alpha particles. For a 10-minute exposure in the cyclotron, about 50 meson tracks are found along the 3-inch edge of a photographic plate. The mass has been determined by measuring the bending in the magnetic field and the range in emulsion. From the first 50 meson tracks measured they find a mass of 313 {+-} 16 electron masses. It is highly probable that these mesons are the heavy mesons described by Lattes, Occhialini, and Powell.
Date: January 1, 1948
Creator: Gardner, Eugene & Lattes, C. M. G.
System: The UNT Digital Library
Production of Mesons by the 184-inch Berkeley Cyclotron Part I. Experimental Arrangement (open access)

Production of Mesons by the 184-inch Berkeley Cyclotron Part I. Experimental Arrangement

The authors have observed traks which they believe to be due to mesons in photographic plates placed near a ta5rget bombarded by 380 Mev alpha particles. The plates used were Ilford Nuclear Research Plates, type C.2. the identification of the particles responsible for the tracks was first made on the basis of the appearance of the tracks; they show the same type of scattering and variation of grain density with residual range found in cosmic ray meson tracks and about two-thirds of them produce observable stars at the end of their range. For a 10-minute exposure in the cyclotron, about 50 meson tracks are found along the 3-inch edge of a photographic plate. Carbon, beryllium, copper, and uranium have been used so far as target materials, and all are found to give mesons. When a carbon target was bombarded with 300 Mev alpha particles, mesons were found but with reduced yield.
Date: April 1, 1948
Creator: Gardner, Eugene & Lattes, C. M. G.
System: The UNT Digital Library
Health and safety conference (open access)

Health and safety conference

This report provides a summary of the Health and Safety Conference held April 1948 at Chicago, Illinois. Representatives of Argonne National Laboratory, Rochester University, University of California Radiation Laboratory, Los Alamos Scientific Laboratory, New York Memorial Hospital, as well as a Canadian group and an United Kingdom group. Many topics were discussed some of which were plutonium in urine, toxicity of beryllium, and relative toxicity of radioelements.
Date: April 1, 1948
Creator: Rudolph, D.C.
System: The UNT Digital Library