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The Luminescence of Chlorophyll-Containing Plant Material

Description: The luminescence of various chlorophyll-containing plant materials has been investigated under a variety of conditions. The results have been shown to be consistent with a mechanism involving the recombination of electrons and holes trapped in a quasi-crystalline lattice. Some details of such a mechanism have been proposed which suggest the mode of entry of the light energy into the photosynthetic pathway.
Date: July 1, 1957
Creator: Tollin, Gordon & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Nuclear Thermodynamics of the Heaviest Elements. II

Description: The masses of the isotopes of the heaviest elements have been calculated from known decay data in the region, extended by means of decay energies calculated from closed decay-energy cycles and estimated from the systematics of alpha and beta decay energies. The absolute values of the masses are based on the mass-spectrometrically determined mass of Pb{sup 208} and a few measured neutron binding energies. The half-life systematics of alpha decay and spontaneous fission are also presented, and some predictions of the properties of as yet undiscovered nuclides are made.
Date: October 1, 1957
Creator: Foreman Jr., Bruce M. & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

Spallation-Fission Competition in Heaviest Elements; HeliumIon-Induced Reactions in Uranium Isotopes

Description: A radiochemical study of fission and spallation products produced by bombardment of U{sup 233}, U{sup 235}, and U{sup 238} with 18-46 Mev helium ions has been made. As in the case of similar studies using isotopes of plutonium as targets, most of the reaction cross section is taken up by fission. Also, the pronounced increase of the total cross section for ({alpha},xn) reactions with increasing mass number of the target that was observed for plutonium targets is observed for uranium targets.
Date: November 1, 1957
Creator: Vandenbosch, R.; Thomas, T.D.; Vandenbosch, S.E.; Glass, R.A. & Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Spallation-Fission Competition in Heaviest Elements; TritonProduction

Description: Stacked f o i l s of Au{sup 197}, Th{sup 232}, and U{sup 238} were bombarded, i n a series of experiments, with 48-Mev helium ions, 24-Mev deuterons, and 32-Mev protons. Tritium from each f o i l was collected and then measured by a gas-counting technique. The qualitative r e s u l t s indicate t h a t high-energy t r i t o n s are emitted i n r e l a t i v e l y large abundance from a l l targets and with each of the bombarding p a r t i c l e s . Cross sections f o r t r i t o n production from fissionable U 238 and Th{sup 232} and from non-f i s s ionable Au{sup 197} are comparable. The integrated (ci,t) cross sections thus determined for and 9lk-1' are nearly the same a s the integrated cross sections f o r the '(,pZn)' reactions as determined by measuring the yield of t h e product heavy isotopes i n radiochemical experiments. A l l of the f a c t s axe consistent with a picture of emission of high-energy t r i t o n s (whether due t o a stripping, pick-up, or other mechanism) i n which fissionable intermediate nuclei are formed mainly a t l e v e l s of excitation be-low t h e i r f i s s i o n thresholds.
Date: March 1, 1957
Creator: Wade, William H.; Gonzalez-Vidal, Jose; Glass, Richard A. & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

Sterility Produced in Mice by Deuterium Oxide

Description: Sterility in C{sub 57} and Swiss mice has been produced by substituting D{sub 2}O for a part of the drinking water. The effective range lies between 5% and 30% D{sub 2}O. It appears that the effect is greater in C{sub 57} males than females and that the size and viability of the litter is affected.
Date: December 6, 1957
Creator: Hughes, Ann M. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Early Unstable CO2-Fixation Products in Photosynthesis

Description: Some chemical, physical, and chromatographic properties of the hydroxylamine stabilized early products of CO{sub 2} fixation in photosynthesis are described. Although no definitive structural information is yet available, these properties, together with the biochemical context in which the material appears, make possible some likely suggestions about the nature of the substances.
Date: December 19, 1957
Creator: Metzner, Helmut; Metzner, Barbara & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

The Effect of D20 on Survival of Mice with Ascites Tumor

Description: The effect of deuterium oxide (D{sub 2}O) on the survival of mice inoculated with Ehrlich's mouse ascites tumor has been studied. Mice maintained on 25% and 30% D{sub 2}O drinking water showed an improved survival time of about 6 days whereas 40% D{sub 2}O drinking water had no effect on survival time. The effect is interpreted in terms of inhibition of tumor cell division and systemic toxicity.
Date: July 1, 1957
Creator: Hughes, Ann M.; Tolbert, Bert M.; Lonberg-Holm, Karl & Calvin,Melvin
Partner: UNT Libraries Government Documents Department

Design and Construction of the Bevatron

Description: This report summarizes the design and construction of the Bevatron (6-Bev proton synchrotron) with emphasis on the engineering problems. It includes specifications, outline drawings, and a bibliography of other reports concerning the subject. Operating results and changes made after the initial start-up in February 1954 are mentioned only briefly.
Date: September 13, 1957
Creator: Brobeck, William M.
Partner: UNT Libraries Government Documents Department

Experiments on Antiprotons: Cross Sections of Complex Nuclei

Description: Experiments are described that have been designed to measure separately annihilation and reaction cross sections for antiprotons of approximately 450 MeV on oxygen, copper, silver, and lead. A new and more luminous spectrograph has been built for this experiment. The antiproton cross sections a r e compared with total proton cross sections, and are found to be larger by a factor varying from 1.74 for oxygen to 1.39 for silver. Calculations based on the optical model give a reasonable connection between these cross sections and the 6-p and 6-n cross sections. Finally, the information available on antiproton production cross sections is collected. There are indications that a free nucleon is several times as effective as a bound one for producing antiprotons.
Date: July 22, 1957
Creator: Agnew, Jr., Lewis E.; Chamberlain, Owen; Keller, Donald V.; Mermod, Ronald; Rogers, Ernest H.; Steiner, Herbert M. et al.
Partner: UNT Libraries Government Documents Department

Cyanide Effects on Carbon Dioxide Fixation in Chlorella

Description: Green algae have been treated with radioactive KCN in an investigation of the effect of cyanide on photosynthesis. A multitude of products have been found to be formed in very short exposures (10 to 15 sec). One of these products has been identified with the product formed when the algae are given radioactive CO{sub 2} and nonradioactive KCN. The same product has been synthesized by a nonenzymatic cyanohydrin addition reaction on ribulose-1, 5-diphosphate. It has been shown to be a 2-carboxy-pentitol (probably mostly ribitol)-1, 5-diphosphate. Upon hydrolysis it gives an hydroxy acid (or mixture of isomers) closely related to hamamelonic acid. The significance of this and the other as yet unidentified products of cyanide interaction with a biological system is discussed with respect to the use of cyanide as an inhibitor.
Date: December 17, 1957
Creator: Rabin, Bernard R.; Shaw, D. F.; Pon, Ning G.; Anderson, J. M. & Calvin, M.
Partner: UNT Libraries Government Documents Department

Action and Emission Spectra of the Luminescence of Green PlantMaterials

Description: The action and emission spectra of the delayed light emission from Chlorella, Nostoc, and spinach chloroplasts have been measured. The action spectra for Chlorella and for spinach chloroplasts are quite similar to the absorption spectra of these materials. The action spectrum for Nostoc, on the other hand, shows a relatively low activity for chlorophyll and carotenoids and a high activity for phycocyanin. The emission spectra of these materials demonstrates that the luminescence is the result of a transition between the first excited singlet state and the ground state of chlorophyll. Low-temperature studies suggest that the triplet state of chlorophyll is not involved at all in the luminescence of spinach chloroplasts. There is some indication that part of the light emitted from Nostoc is due to a phycocyanin transition.
Date: December 29, 1957
Creator: Tollin, G.; Fujimori, E. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

The Free Radical from Perinaphthene

Description: The electron spin resonance spectrum of the perinaphthene free radical is reported and a discussion of electron spin density in this radical is given.
Date: January 31, 1957
Creator: Sogo, Power B.; Nakazaki, Masao & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Experiments on Antiprotons: Antiproton-Nucleon CrossSections

Description: In this paper experiments a r e reported on annihilation and scattering of antiprotons in H{sub 2}O , D{sub 2}O, and O{sub 2}. From the data measured i t i s possible to obtain an antiproton-proton and a n antiproton-deuteron c r o s s section a t 457 Mev (lab). Further analysis gives the p-p and p-n c r o s s sections a s 104 mb for the H-p reaction c r o s s section and 113 mb for the p-n reaction c r o s s section. The respective annihilation cross sections a r e 89 and 74 mb. The Glauber correction necessary in order to pass from the p-d to the p-n c r o s s section by subtraction of the p-p c r o s s section i s unfortunately large and somewhat uncertain. The data a r e compared with the p-p and p-n c r o s s sections and with other results on p - p collisions.
Date: July 22, 1957
Creator: Chamberlain, Owen; Keller, Donald V.; Mermond, Ronald; Segre,Emilio; Steiner, Herbert M. & Ypsilantis, Tom
Partner: UNT Libraries Government Documents Department

The Primary Quantum Conversion Process in Photosynthesis: ElectronSpin Resonance

Description: Photoinduced electron spin resonance signals have been observed in isolated chloroplasts and other green materials with a growth time not affected by reducing the temperature to -140 deg. This is interpreted in terms of conduction-band and trapped-electron theory.
Date: January 28, 1957
Creator: Calvin, Melvin & Sogo, Power B.
Partner: UNT Libraries Government Documents Department

A Coaxial Static-Electromagnetic Velocity Spectrometer for HighEnergy Particles

Description: An apparatus is described in which crossed E and H fields will be used to separate high-energy charged particles of different masses. It is shown that use of coaxial geometry is expected to effect satisfactory separation within a considerably shorter system than would be possible in a parallel-plate system with a comparable separation criterion, A summary is given of the operational characteristics of a spectrometer now under construction.
Date: May 7, 1957
Creator: Murray, Joseph J.
Partner: UNT Libraries Government Documents Department