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The level structure of neutron-deficient ('121)Xe, ('123)Xe and ('124)Xe was studied. These levels were populated in the (beta)-decay of ('121)Cs, ('123)Cs and ('124)Cs respectively, which were produced by the proton bombardment of isotopically enriched ('124)Xe gas targets. Using (gamma)- and (beta)-spectroscopy techniques the level structures of these isotopes were obtained. / High-spin levels of ('122)Xe and ('124)Xe populated in the ((alpha),4n(gamma)) reaction on enriched tellurium targets, were investigated. Gamma-ray-multiplicity filter, and angular distribution measurements have been carried out. The observation of the backbending of the ground band, and of the two-quasi-particle high-spin bands in ('122,124)Xe, is the first in xenon nuclei. These bands were interpreted in the framework of the rotation-alignment picture. / A theoretical interpretation of ('116-130)Xe nuclei was performed using the Interacting Boson Approximation. Also the levels in ('121)Xe were interpreted using the Interacting Boson-Fermion Model.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1956. / Typescript. Abstracted in Dissertation abstracts, v. 16 (1956) no. 10, p. 1808. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 117-119).

Thesis (Ph. D.)--University of Chicago, 1921. / "Private edition distributed by the University of Chicago libraries, Chicago, Illinois." "Reprinted from the Journal of the American chemical society, vol. 44, no. 1, January, 1922." Also available on the Internet.

Thesis (Ph. D.)--Columbia University, 1934. / Vita. Bibliography: p. 1 leaf at end.

Thesis (Ph. D.)--Columbia University, 1924. / Vita.

The cross section for the photodisintegration of helium-3 has been measured at gamma ray energies of 8.06 and 9.17 mev. The He³ (ɣ,p)D reaction cross section at 8.06 and 9.17 mev was found to be 0.493± 0.066 and 0.723± 0.087 millibarns respectively. The He³ (ɣ,n)2p reaction cross section at 9.17 mev was found to be 0.25± 0.13 millibarns. These results are compared with other experimental work on the photodisintegration of helium-3 and tritium. The photodisintegration reaction was observed in a cylindrical gridded ionization chamber using a helium-3, methane, and argon gas mixture. The C¹³ (p,ɣ) N¹⁴ reactions at proton bombarding energies of 0.554 and 1.75 mev were used as the source of gamma rays of well defined energy. The preparation of carbon-13 targets is discussed in detail. Theoretical calculations on the photodisintegration of mass 3 nuclei are summarized. Photodisintegration and electron scattering measurements are compared as methods of determining the nature of the ground state wave function of the mass 3 system. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

In earlier studies by Beer¹ the alkadloid vinblastine, VLB, has been shown to cause an almost complete inhibition in the incorporation of C¹⁴-formate into the deoxyribonucleic acid (DNA) of rat bone marrow in vivo. Also the incorporation of the same isotope into the DNA of suspensions of rat bone marrow and thymus cells in vitro was substantially depressed within one hour by the presence of the alkaloid² . In this work, the effect of VLB on the incorporation of C¹⁴-formate into the purine and pynmidine bases isolated from the hydrolysed acid-soluble fraction of thymus cell preparations was studied. A method for the separation of the constituents of this fraction was standardized and some of the major ultraviolet absorbing and radio-active compounds were identified. In general, VLB did not cause a marked depression in the incorporation of C¹⁴ -formate into the bases isolated from the hydrolysed acid-soluble fraction of either washed or unwashed cell suspensions. It was therefore considered probable that vinblastine did not inhibit the activation of 1-carbon units by tetrahydrofolic acid or their transfer. Also the results indicated that the de novo synthesis of the purine and pyrimidine compounds was not inhibited by the alkaloid. It is tentatively suggested that VLB inhibits a step in the incorporation of the mononucleotides into the nucleic acids. Comparison of the compounds isolated from the hydrolysed acid-soluble fractions of washed and unwashed cell preparations showed that considerably less hypoxanthine and xanthine were recovered from the former. VLB was found to markedly increase the total radio-activity of serine in washed cell preparations in the third hour of incubation but this effect was not pronounced in unwashed cell preparations. The total count of adenine decreased in the third hour of washed cell incubations in the presence of VLB. Neither the effect on serine nor on adenine is considered to be directly related to the inhibition of DNA synthesis as the latter is apparent within only 1 hour's incubation. Washing appears to increase the sensitivity of certain biochemical changes in the cell. It is tentatively suggested that the appearances of changes in the total radio-activity of adenine may be related to the loss of a substrate on washing. 1 Beer, C.T., Canadian Cancer Conference 4, 355 (1961) Academic Press, Inc., New York. 2 Richards, J.F., and Beer, C.T., personal communication. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate

A critical survey has been conducted on the research done in oxygen isotopes. Only those aspects are considered which are of interest to the earth scientists. Oxygen isotopes have been used for geothermometric purposes and for rock genesis problems. The physical principles underlying these two lines of research are stressed. Assumptions which are usually implied are explicitly stated. It is shown that the influence of pressure on the equilibrium constant of oxygen isotope exchange reactions is only a minor one in comparison with the temperature influence. The significance of determined temperatures is discussed in the light of possible oxygen diffusion in silicates and carbonates. It is concluded that diffusion is usually neglected without justification. As far as data are available it is shown that diffusion can be responsible for many discrepancies between oxygen isotope temperatures and' temperatures derived by other means. Studies on the origin of rocks by means of oxygen isotopes are discussed. Attention is focussed on the Southern Californian batholith. The results of Taylor and Epstein's preliminary study of this batholith are interpreted here as evidence in favour of a metamorphic origin of this huge rock body. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The purpose of this thesis is to investigate the isotopic composition of primary leads. The leads analysed were selected by R. L. Stanton in accordance with his geologic description for conformable deposits. It was anticipated that, of all available terrestrial leads, these were the least likely to have been modified isotopically by crustal processes. Detailed analyses and interpretations for fifty-six samples from nine different districts in Eastern Australia, Tasmania, Canada and New Zealand are presented. A precision of better than ±.05 per cent in the measurement of the Pb²⁰⁶/Pb²⁰⁴, Pb²⁰⁷/Pb²⁰⁴ and Pb²⁰⁸/Pb²⁰⁴ ratios was achieved for all samples by means of an intercomparison technique derived from that used by P. Kollar and R. D. Russell, and improved methods for reducing the data. As expected, the geologic criteria used by Stanton to identify conformable deposits have been found to be sufficient to identify deposits which are very uniform in isotopic composition. The findings of this research indicate that the criteria, although remarkably good, are not completely adequate for identifying primary leads. In particular, leads from two conformable deposits (Manitouwadge and Rosebery) were found to be anomalous, and those from two other deposits (Hall's Peak and Bathurst) may be anomalous. The single-stage lead model was found to be a very good approximation for isotopic development of the leads from the remainder of the conformable deposits studied by the writer, as well as for leads analysed by other workers at the University of British Columbia and assumed to be primary. These results suggest that primary leads have formed in a region for which there are very narrow limits of ±.6% and ± .8% to the variations in U²³⁸/Pb²⁰⁴ and Th/U ratios. They substantiate the hypotheses of Russell and Stanton that: (1) primary leads lie very closely to a unique single-stage growth curve in a plot of the ratios Pb²⁰⁷/Pb²⁰⁴ against Pb²⁰⁶/Pb²⁰⁴, and in a plot of Pb²⁰⁸/Pb²⁰⁴ against Pb²⁰⁶/Pb²⁰⁴; (2) leads away from this growth curve are anomalous. From the fit of the conformable leads to a single-stage growth curve, values of 4.52 ± .03 Gyr. and 4.54 ± .02 Gyr. have been calculated for the age of the earth. With the identification of a unique growth curve for primary leads, severe restrictions are placed on anomalous lead interpretations. These are illustrated in the interpretations of anomalous leads studied by the writer. / Science, Faculty of / Physics and Astronomy, Department of / Graduate