Showing papers by "Pacific Northwest National Laboratory published in 1968"
140 citations
TL;DR: In this paper, phase relations in the americium-oxygen system between 1·50 < O/Am < 2·00 were studied using Guinier and Debye diffraction methods on quenched and annealed samples.
92 citations
TL;DR: In this article, the authors investigated the nature and magnitude of radiation hardening in an 18-8 type austenitic stainless steel after a high neutron exposure (1.4 × 1022 n/cm2, E > 0.18 MeV) near one-half the absolute melting temperature (532°C).
87 citations
TL;DR: It was inferred that the rate of tryptophan transport in Neurospora is modulated through the maintenance of a delicate balance between the synthesis and breakdown of some component of the transport system.
Abstract: The rate of tryptophan transport in Neurospora is regulated by the intracellular pool of tryptophan. When cells were shifted from growth in minimal medium to tryptophan-containing medium for 10 min, there was a 50% reduction in the rate of tryptophan transport. Intracellular tryptophan pools derived from indole were equally effective in reducing the rate of transport as externally supplied tryptophan. The regulatory influence of tryptophan on the transport system appears to be a property of all the amino acids transported by the tryptophan transport site or sites. Lysine and glutamic acid are not transported by the tryptophan transport site or sites and are ineffective in the regulation of tryptophan uptake. Continued protein synthesis is required for the maintenance of a functional tryptophan transport system. The half-life of the transport system, estimated by inhibiting protein synthesis with cycloheximide, was about 15 min. Turnover of the system occurred at 30 C but not at 4 C, suggesting that the breakdown of the system is enzymatically mediated. It was inferred that the rate of tryptophan transport in Neurospora is modulated through the maintenance of a delicate balance between the synthesis and breakdown of some component of the transport system.
58 citations
TL;DR: The extreme sensitivity of this instrument to air bubbles in the circulating fluid is exploited for the in vivo detection of circulating gas emboli in an animal decompressed rapidly from a hyperbaric environment.
Abstract: THE ultrasonic Doppler flowmeter1 has been used to measure blood flow in several animal species2,3 and man4,5 by monitoring the frequency shift produced in the scattering of ultrasonic waves by moving blood cells. The extreme sensitivity of this instrument to air bubbles in the circulating fluid is a familiar nuisance encountered during in vitro testing and calibration procedures. We have exploited this characteristic for the in vivo detection of circulating gas emboli in an animal decompressed rapidly from a hyperbaric environment.
51 citations
TL;DR: Tetragonal ZrO2 can be formed directly from the mono-clinic form at 25°C by applying pressures greater than 37 kbar as discussed by the authors, but the transition is reversible and cannot be retained in a metastable condition at ambient conditions.
Abstract: Tetragonal ZrO2 can be formed directly from the mono-clinic form at 25° C by applying pressures greater than 37 kbars. The transition is reversible, and the tetragonal phase cannot be retained in a metastable condition at ambient conditions.
47 citations
TL;DR: Greasewood and hopsage shrubs growing together on the same ground accumulated large amounts of sodium and potassium respectively as mentioned in this paper, and the decay of accumulated leaf litter beneath the canopy spread of these shrubs has altered the soil chemistry over about 20 per cent of the ground area.
Abstract: Greasewood and hopsage shrubs growing together on the same ground accumulated large amounts of sodium and potassium respectively. The decay of accumulated leaf litter beneath the canopy spread of these shrubs has altered the soil chemistry over about 20 per cent of the ground area. About 14 per cent of the surface soil area is being supplied with sodium and about 7 per cent of the area is being supplied with potassium. At the present time minerals are being supplied at a rate faster than they can be leached away. The location od shrubs needs to be considered when collecting soil samples for studies of effects of certain kinds of desert shrubs on chemical and physical properties of soil.
45 citations
TL;DR: A system for direct observation of excited state optical mean lives using the delayed coincidence counting technique is described, which uses a pulsed proton beam for excitation, a high speed time-to-amplitude converter and an on-line digital computer for data reduction.
Abstract: A system for direct observation of excited state optical mean lives using the delayed coincidence counting technique is described. The system uses a pulsed proton beam for excitation, a high speed time-to-amplitude converter and an on-line digital computer for data reduction. Mean lives longer than 1 nsec can be measured. Preliminary measurements on the 31P, 43S, and 41D levels of helium and several vibrational bands of N2 are presented to illustrate the capabilities of the system.
42 citations
40 citations
TL;DR: The accumulation of imidazoleglycerol phosphate during growth of Neurospora crassa in the presence of 3-amino-1,2,4-triazole was found to cause derepression of tryptophan synthetase and to inhibit the induction of kynureninase.
Abstract: The accumulation of imidazoleglycerol phosphate during growth of Neurospora crassa in the presence of 3-amino-1,2,4-triazole was found to cause derepression of tryptophan synthetase and to inhibit the induction of kynureninase. Accumulation of indoleglycerol phosphate in response to growth in the presence of indole acrylic acid or anthranilic acid was also accompanied by derepressed synthesis of tryptophan synthetase. Enzyme synthesis in mutants (his-7 and trp-4) unable to form these intermediates was not altered under similar conditions. The rate of formation of tryptophan synthetase and kynureninase was found to differ in the presence of tryptophan and indole.
33 citations
TL;DR: Three emittance-independent ir nondestructive testing techniques are described, two of these use the dual scan ratio principle, and the other uses energy reflected from the test specimen surface to compen.
Abstract: Three emittance-independent ir nondestructive testing techniques are described. Two of these use the dual scan ratio principle, and the other uses ir energy reflected from the test specimen surface to compensate for emittance differences. Complete details on the theory behind the three techniques are given-Instrumentation used to carry out tests and the results of two practical applications are described.
TL;DR: Concentration of the radio nuclide beryllium-7, produced by cosmic rays, was measured in waters collected from both the Atlantic and Pacific oceans and found to be well suited as a tracer for interactions at the air-sea interface and for the measurement of rapid mixing processes in the surface layer of the ocean.
Abstract: Concentration of the radio nuclide beryllium-7, produced by cosmic rays, was measured in waters collected from both the Atlantic and Pacific oceans. This short-lived nuclide is well suited as a tracer for interactions at the air-sea interface and for the measurement of rapid mixing processes in the surface layer of the ocean.
TL;DR: In the case of grey boronated graphite, the B4C is not as accessible to the oxidant as the B2O3 as mentioned in this paper, and the amount of B4O3 formed is greater than that of black BORONATED graphite.
TL;DR: The ability of pulmonary macrophages to rapidly phagocytize and retain plutonium particles deposited in the lungs has been shown.
Abstract: Pulmonary macrophages and plutonium particles were removed by washing the lungs of rats that had inhaled plutonium oxide-239Pu. A significant amount of plutonium was found in multiple washings of the same lung. The removal of toxic particles by washing is of potential therapeutic value. Particles were phagocytized by macrophages during the first 3 hours and retained within these cells for up to 25 days. Nearly all particles in washings were found in macrophages after the second day. The percent of macrophages with engulfed particles increased with increasing amounts of plutonium deposited in the lungs. The ability of pulmonary macrophages to rapidly phagocytize and retain plutonium particles deposited in the lungs has been shown.
TL;DR: In this paper, the microstructural damage and its subsequent recovery in molybdenum, irradiated at 600°C, was studied by quantitative electron microscopy, and the microstructure after irradiation consisted of large interstitial loops and smaller clusters within the grains.
TL;DR: In this article, the authors investigated the effect of irradiation on the creep rate of heat treated Zr-2 rods and found that the increase in creep rate was due to the growth of stress oriented dislocation loops limited by the generation rate of point defects.
TL;DR: These measurements provide a method for studying the in-cloud nucleation times and aerosol scavenging efficiencies, and promise to provide information on short-term processes which occur in rain and snow formation.
Abstract: Through recent developments in instrumental analysis it is now possible to measure with good precision the rainwater concentrations of five short-lived radionuclides which are produced by cosmic ray spallation of atmospheric argon. These measurements provide a method for studying the in-cloud nucleation times and aerosol scavenging efficiencies, and promise to provide information onshort-term processes which occur in rain and snow formation.
TL;DR: Circulating gas emboli associated with rapid decompression are detectable in superficial vessels of animals by the use of an ultrasonic Doppler flowmeter transducer which is applied externally.
Abstract: Circulating gas emboli associated with rapid decompression are detectable in superficial vessels of animals by the use of an ultrasonic Doppler flowmeter transducer which is applied externally.
TL;DR: The methods of wound management including surgical removal of the plutonium, use of chelating agents, the methods of evaluating the residual deposition of plutonium, and hopefully indicates areas of needed research are described.
Abstract: When an acute internal exposure to plutonium occurs, a number of problems arise for consideration by the treating physician and the attending physicist. A recent plutonium wound incident at Hanford involving the laceration of an employee's arm by plutonium fragments, has again emphasized these problems and the need for great care in wound and patient management, both from a medical and physical standpoint. This paper describes the methods of wound management including surgical removal of the plutonium, use of chelating agents, the methods of evaluating the residual deposition of plutonium, and hopefully indicates areas of needed research.
TL;DR: An enigmatic parasite is revealed in the maturing ova of the Pacific oyster from Humboldt Bay, Calitornia during two successive years, and presumably belongs among the protozoa.
TL;DR: A unique internal tumor in an oyster is described, along with a discussion of its possible origin, and a benign fibrous tumor of possible myogenic or gonadal origin is diagnosed.
TL;DR: Sensitivities of species and strains of Tribolium to X-radiation were tested at significant life-cycle stages, with larvae more sensitive than earlier larval stages, and in all stages the confused flour beetle.
Abstract: Sensitivities of species and strains of Tribolium to X-radiation were tested at significant life-cycle stages. Eggs Were most sensitive, 1–3 kr required for lethality, and adults least sensitive, LD100 8–15 kr and sterilizing dose 4–6 kr. Larval and pupal sensitivities were intermediate with 18-day-old larvae more sensitive than earlier larval stages, In all stages the confused flour beetle. Tribolium confusum Jacquelin duVal (strain Chicago Standard) was more sensitive than strains of the red flour beetles Tribolium castaneum (Herbst) (strains Brazil cl and sooty).
TL;DR: In this paper, the one-dimensional constant stress and constant strain models were used to calculate Young's moduli and coefficients of thermal expansion as a function of crystallite orientation in polycrystalline graphite.
TL;DR: In this paper, an anticoincidence-shielded Ge(Li) gamma-ray spectrometer for high sensitivity counting is described, which consists of a 20 cc coaxial diode centered inside a 26" diameter by 24" thick plastic phosphor.
Abstract: An anticoincidence-shielded Ge(Li) gamma-ray spectrometer for high sensitivity counting is described. The system consists of a 20 cc coaxial diode centered inside a 26" diameter by 24" thick plastic phosphor. The source is placed inside the shield and both the coincidence and anticoincidence spectra are recorded simultaneously. The anticoincidence shield reduces the 137Cs Compton edge by a factor of 7.5 to provide a peak to Compton edge ratio of 150:1 without reducing the photopeak efficiency by more than 3%. This system also provides a two to fourfold lower natural radionuclide background than similar sized diodes.
01 Jan 1968
TL;DR: The results indicate that the physical-chemical state of inhaled plutonium dioxide influences its disposition in the body as well as retention, translocation, and rates of excretion.
Abstract: Groups of three dogs were given single inhalation exposures to dry aerosols of one of four different plutonium dioxides to compare retention, translocation, and rates of excretion. Two of the plutonium dioxides were prepared by calcining the oxalate at 350°C and at about 1000°C. Two others were produced by ignition of the stabilized delta metal at 450°C and by slow oxidation of the pure metal at 123°C. The lung retention half-time of the oxalate calcined at 350°C was about one year, half that of the other oxides. This was due to greater accumulation of plutonium in the bronchial lymph nodes rather than greater clearance via the mucus-ciliary pathway or a relatively high rate of solubility. The metal oxidized at 450°C was cleared via the mucus-ciliary route to a lesser extent than the other oxides. This same oxide also showed a selective loss of 241Am, relative to 239Pu, in lung and bronchial lymph node tissue which was not evidenced by the other oxides. The oxalate calcined at 1000°C showed the least translocation to tissues outside the respiratory tract. These results indicate that the physical-chemical state of inhaled plutonium dioxide influences its disposition in the body.
TL;DR: In this paper, a lithium-drifted silicon diode was used as an x-ray detector on an electron microprobe to obtain rapid qualitative and quantitative results on particle samples.