Showing papers by "Pacific Northwest National Laboratory published in 1981"
TL;DR: In two replicate experiments there were statistically significant differences between exposed and control rats in that the normal nocturnal increase in pineal melatonin content was depressed in the exposed animals.
Abstract: As a component of studies to search for effects of 60-Hz electric field exposure on mammalian endocrine function, concentrations of melatonin, 5-methoxytryptophol, and serotonin-N-acetyl transferase activity were measured in the pineal glands of rats exposed or sham-exposed at 65 kV/m for 30 days.In two replicate experiments there were statistically significant differences between exposed and control rats in that the normal nocturnal increase in pineal melatonin content was depressed in the exposed animals. Concentrations of 5-methoxytryptophol were increased in the pineal glands of the exposed groups when compared to sham-exposed controls. An alteration was also observed in serotonin-N-acetyl transferase activity, with lower levels measured in pineal glands from exposed animals.
180 citations
TL;DR: In this paper, single crystals of stoichiometric UO 2 have been irradiated at room temperature with alpha particles emitted from an effectively semi-infinite 238 PuO 2 source to a dose of 3 × 10 16 alphas/cm 2.
138 citations
89 citations
TL;DR: Washout ratios for sulfate were computed from simultaneous measurements of sulfate in precipitation and in the air below cloud base as mentioned in this paper, and it was shown that for cases of accretional growth, the washout ratio was 10 to 50 times larger than for case of depositional growth, and that the contribution due to nucleation scavenging and/or aqueous phase conversion of SO2 to SO4 in the cloud water.
Abstract: Washout ratios for sulfate were computed from simultaneous measurements of sulfate in precipitation and in the air below cloud base. Stratification of the data according to predominant mode of precipitation growth (growth primarily by accretion of liquid cloud droplets versus growth primarily by vapor deposition onto ice particles) illustrated that for cases of accretional growth, the washout ratio was 10–50 times larger than for cases of depositional growth. The depositional growth mode appeared to be a baseline value and was determined by the efficiency of below-cloud scavenging. Sulfate washout ratios (mass weighted) for this baseline value ranged between 1 and 800 and typically averaged near 100. Enhancement of this baseline value caused by accretional growth was a measure of the contribution due to nucleation scavenging and/or aqueous phase conversion of SO2 to SO4 in the cloud water. This accretional mode increased the sulfate washout ratio to values averaging near 1000. Values of the washo...
86 citations
TL;DR: An analysis is given of the interaction between extremely low-frequency (ELF) electric fields and animals of arbitrary body shape based on three approximations which are valid in the ELF range.
Abstract: An analysis is given of the interaction between extremely low-frequency (ELF) electric fields and animals of arbitrary body shape. This analysis is based on three approximations which are valid in the ELF range: In living tissues, capacitive (displacement) currents are negligible compared to conduction currents; effects resulting from the finite velocity of propagation of electromagnetic fields are negligible; skin effect in living tissues is negligible. Major conclusions of the analysis are: (a) The electric field outside the body, the induced charge on the surface of the body, and the total current crossing any section through the body (eg, through the neck or limbs) are completely determined by the characteristics of the applied ELF electric field, the shape of the body, its location relative to ground and other conductors, and any conduction currents from the body to ground or other conductors. (b) All of the quantities in (a) can be measured using conducting animal models. (c) The magnitudes of the electric field outside the body and the induced charge density on the surface of the body are independent of frequency, in the ELF range, when the body is either insulated from or shorted to ground (and any other conductors in the system). (d) The only quantities affected by the electrical properties of the tissues comprising the body are the current density and electric field inside the body. (e) The electric field outside and inside a body will be unchanged by a scaled change in its size.
84 citations
TL;DR: In this article, the authors presented spectra of the time series of wind speeds and temperatures measured in the outflow area of a large drainage region, where peaks are found in these spectra at frequencies corresponding to periods of oscillation of ∼1.5 h.
Abstract: Spectra of the time series of wind speeds and temperatures measured in the outflow area of a large drainage region are presented. Peaks are found in these spectra at frequencies corresponding to periods of oscillation of ∼1.5 h. A simple model is given, which accounts qualitatively for some of the observed features.
74 citations
TL;DR: It is concluded that 60-Hz electric fields may bring about subtle changes in the endocrine system of rats, and that these changes may be related to alterations in episodic rhythms.
Abstract: Adult male rats were exposed or sham-exposed to 60-Hz electric fields without spark discharges, ozone, or significant levels of other secondary variables. No effects were observed on body weights or plasma hormone levels after 30 days of exposure at an effective field strength of 68 kV/m. After 120 days of exposure (effective field strength = 64 kV/m, effects were inconsistent, with significant reductions in body weight and plasma levels of follicle-stimulating hormone and corticosterone occurring in one replicate experiment but not in the other. Plasma testosterone levels were significantly reduced after 120 days of exposure in one experiment, with a similar but not statistically significant reduction in a replicate experiment. Weanling rats, exposed or sham-exposed in electric fields with an effective field strength of 80 kV/m from 20 to 56 days of age, exhibited identical or closely similar growth trends in body and organ weights. Hormone levels in exposed and sham-exposed groups were also similar. However, there was an apparent phase shift between the two groups in the cyclic variations of concentrations of hormones at different stages of development, particularly with respect to follicle-stimulating hormone and corticosterone. We concluded that 60-Hz electric fields may bring about subtle changes in the endocrine system of rats, and that these changes may be related to alterations in episodic rhythms.
65 citations
TL;DR: In this paper, field and laboratory experiments examined how oiled sediment influenced predation on littleneck clams, Protothaca staminea, by Dungeness crabs, Cancer magister.
Abstract: Field and laboratory experiments examined how oiled sediment influenced predation on littleneck clams, Protothaca staminea, by Dungeness crabs, Cancer magister. In two field enclosure experiments lasting 13 and 29 days crabs consumed more clams from oiled than clean sand. Clams were shallower in oiled than clean sand. To test whether the observed increase in predation rate on clams from oiled sand was due to shallow burial, a 19-day laboratory experiment examined predation rates on clams buried in different depths of sand. The high consumption of clams from shallow-clean sand indicated that shallow burial could have accounted for most but not all the higher consumption of clams in oiled sand. In a second laboratory experiment without crabs, clams were again shallower in oiled than clean sand. Clams did not actively emerge from oiled sand but did burrow slower into oiled sand. Shallow burial and slow reburrowing in oiled sand led to increased predation of littleneck clams through increasing the accessibility of clams to Dungeness crabs.
63 citations
TL;DR: In this paper, the authors examined the unimolecular reaction HCOHCO→H2+CO+CO via non-empirical molecular electronic structure theory, and showed that the barrier for this ABC→A+B+C reaction is competitive with that for H 2 CO+CO. This suggests the existence of a slightly nonplanar true transition state.
Abstract: Following an earlier proposal [Y. Osamura and H. F. Schaefer, J. Chem. Phys. 74, 4576 (1981)], the unimolecular reaction HCOHCO→H2+CO+CO has been examined via nonempirical molecular electronic structure theory. Specifically, the constrained symmetric (point group C2v) transition state for this ABC→A+B+C reaction has been located at several levels of self‐consistent‐field (SCF) theory. Four different basis sets of contracted Gaussian functions were used: an STO‐3G minimum basis, the small split valence 3‐21G basis, the standard C(9s 5p/4s 2p) double zeta (DZ) set, and a double zeta plus polarization (DZ+P) basis. Vibrational analyses of the four stationary point structures (all of which are geometrically similar) yield a remarkable variety of results. The STO‐3G stationary point has three imaginary vibrational frequencies, 3‐21G has one imaginary frequency (and thus is a genuine transition state), while the DZ and DZ+P structures yield two imaginary vibrational frequencies. For the latter two cases, one of the two imaginary vibrations is a very small bending frequency, while the larger frequency clearly connects glyoxal with the three products H2+CO+CO. This suggests the existence of a slightly nonplanar true transition state. To our knowledge such a unimolecular transition state is without precedent. Configuration interaction (CI) suggests that the barrier for this ABC→A+B+C reaction is competitive with that for HCOHCO→H2CO+CO.
56 citations
TL;DR: In this paper, the first and second derivatives of a configuration interaction energy with respect to an external parameter were derived for a general multiconfiguration Hartree-Fock wave function.
Abstract: Equations providing the first and second derivatives of a configuration interaction (CI) energy with respect to an external parameter are provided. We assume no restriction on the form of the CI expansion built from molecular orbitals obtained in a multiconfiguration Hartree–Fock (MCHF) calculation. Also, the coupled perturbed multiconfiguration Hartree‐Fock formalism is presented for a general MCHF wave function and provides the first order and second order changes of the molecular orbital expansion coefficients with respect to an external parameter.
56 citations
TL;DR: In this article, the first application of non-empirical molecular electronic structure theory to a realistic transition metal carbene complex was reported, and the system chosen was (CO){sub 3}NiCH{sub 2}, methylene (tricarbonyl) nickel(0).
Abstract: The first application of nonempirical molecular electronic structure theory to a realistic transition metal carbene complex is reported. The system chosen was (CO){sub 3}NiCH{sub 2}, methylene (tricarbonyl) nickel(0). All studies were carried out at the self-consistent-field (SCF) level. A large and flexibly contracted basis set was chosen, labeled Ni(15s 11p 6d/11s 8p 3d); C,O(9s 5p/4s 2p); H(5s/3s). In addition, the importance of methylene carbon d functions was investigated. The critical predicted equilibrium geometrical parameters were R [Ni-C (methylene)]=1.83 {Angstrom}, {theta}(HCH)=108°. The sixfold barrier to rotation about the Ni-C (methylene) axis is small, ~o.2 kcal. The electronic structure of (CO){sub 3}NiCH{sub 2} is discussed and compared with those of the "naked" complex NiCH{sub 2} and the stable Ni(CO){sub 4} molecule.
TL;DR: Significant increases in the leaching rate of PNL 76-68, a complex simulated nuclear waste glass, were observed to occur in the presence of gamma radiation as discussed by the authors, indicating that some of the enhanced leaching is due to the generation of nitric acid from air radiolysis.
Abstract: Significant increases in the leaching rate of PNL 76–68, a complex simulated nuclear waste glass, were observed to occur in the presence of gamma radiation. Some of the enhanced leaching is due to the generation of nitric acid from air radiolysis in the leach vessel. Nitric acid appears to preferentially attack zinc and lanthanides, both of which normally build up on the surface of the glass when leached in nonacidic solutions. Increased rates were also found for samples irradiated while leaching but with air excluded to eliminate nitric acid formation, indicating that water radiolysis products may also be important. Samples irradiated prior to leaching showed dissolution rates indistinguishable from those of unirradiated specimens.
TL;DR: In this paper, the authors extended symmetry methods employed in the ab initio polyatomic program HONDO to the analytic computation of the energy Hessian matrix, which is generated by projecting the symmetric component out of the skeleton Hessian.
Abstract: Symmetry methods employed in the ab initio polyatomic program HONDO are extended to the analytic computation of the energy Hessian matrix. A ’’skeleton’’ Hessian matrix is calculated from the unique blocks of electron repulsion integrals. The true Hessian matrix is generated by projecting the symmetric component out of the skeleton Hessian. The analysis is valid for many wave functions, including closed‐ or open‐shell restricted and unrestricted Hartree–Fock wave functions, multiconfiguration Hartree–Fock wave functions, and configuration interaction wave functions. We also extend the use of translational invariance previously used for energy gradient calculations. To illustrate the method, we compare the computer time required for the two‐electron contribution to the Hessian matrix of eclipsed ethane, using Pople’s 6‐31G basis set and D3h symmetry and various subgroups of D3h. Computational times are roughly inversely proportional to the order of the point group.
TL;DR: In this article, the authors collected samples of atmospheric particulate matter and total atmospheric deposition for a one-year period at a rural site on the Washington coast and analyzed them for 13 stable elements and 7 Be.
TL;DR: In this paper, the effect of thorium oxalate precipitation conditions on derived oxide sinterability was investigated on a laboratory scale with the objective of producing ThO2 powder that could be sintered to high density without milling.
TL;DR: In this paper, the authors compared coal-liquefaction material with its catalytically hydrogenated products with regard to biological activity and chemical composition, and found that the mutagenic activity of the moderate and severly hydrogenated product was substantially reduced compared to that of the feedstock.
TL;DR: In this paper, the authors examined parameters controlling the formation of non-protective oxides on 304 stainless steel by using Auger electron spectroscopy to monitor oxides formed in the vacuum chamber.
TL;DR: The amino acid composition was similar to a cadmium-binding protein of mussels reported by other researchers and the relatively low amounts of half-cystine and the presence of aromatic amino acids and histidine were not characteristic of metallothionein.
TL;DR: In this paper, the stability of Pu(IV) polymer suspensions, the solubility of the polymer, and the nature of the soluble plutonium species were studied from pH 3 to 7 in dilute chloride and in diluted nitrate solutions.
Abstract: The stability of Pu(IV) polymer suspensions, the solubility of the polymer, and the nature of the soluble plutonium species were studied from pH 3 to 7 in dilute chloride and in dilute nitrate solutions. Previous work on the polymer did not address such environmentally important properties as the concentration of soluble plutonium present along with the polymer, the nature of the solute species, and the stability of polymer suspensions at near-neutral pH values. This study was undertaken to answer these questions. 15 refs.
TL;DR: In this article, the lowest rejected concentration tested (LRCT) is recommended as an experimental end point for no-observed-effect level (NOEL) testing. But the use of LRCT violates the principle of negative inference, the logical basis of statistical hypothesis testing.
Abstract: Use of the no-observed-effect level (NOEL) as an experimental end point violates the principle of negative inference, the logical basis of statistical hypothesis testing. The NOEL is based on the nonrejection of the hypothesis of no toxic effect, whereas scientific methods stress conclusions based on the rejection of a hypothesis. Failure to reject this hypothesis may result either because the concentration is safe or because the experimental protocol to detect a toxic response is insensitive, but the cause is indeterminant and the error rate unknown. The lowest rejected concentration tested (LRCT) is recommended as an experimental end point. By the use of LRCT the rate of misclassification is known and is equal to ..cap alpha... Experimental designs that emphasize both the biological and the statistical significance of LRCT end points are recommended.
TL;DR: In this article, the thermal stability of amorphous (glassy) binary alloys is discussed. And the alloy preparation method, crystallization temperature, and method of measurement of crystallisation temperature are tabulated.
Abstract: Data on the thermal stability of amorphous (glassy) binary alloys are compiled. Where available, alloy preparation method, crystallization temperature and method of measurement of crystallization temperature are tabulated. Other relevant aspects such as crystallized phases and compositions, glass transition temperature and analytical parameter variations also are given when data are available.
TL;DR: Solvent refined coal distillates produced by 2 different pilot plant processes were compared for mutagenicity using the Ames/salmonella assay and the most active of the SRC subfractions were comparable in Mutagenicity to benzo[a]pyrene, but substantially less active than 2-aminoanthracene.
Abstract: Solvent refined coal (SRC) distillates produced by 2 different pilot plant processes were compared for mutagenicity using the Ames/Salmonella assay. The highmolecular-weight, high-boiling SRC distillates were fractionated into their various constituent chemical classes for Ames analysis. In each case, the major portion of the mutagenic activity contained in the crude materials was recovered in the basic and in the tar fractions. Little or no activity was found in the neutral, aliphatic, or neutral polyaromatic hydrocarbon (PAH)-enriched fractions. The most active of the SRC subtraction were comparable in mutagenicity to benzo[ a ]pyrene, but substantially less active than 2-aminoanthracene.
TL;DR: A strong correlation was observed between the concentration of PAAs in a given TLC region and the mutagenicity of that region in the Ames assay system, and azaarenes having 2--4 fused rings and carbazoles were present in both mutagenic and non-mutagenic TLC eluates.
Abstract: Thin-layer chromatography (TLC) was used to separate components in the basic and tar fractions of solvent refined coal (SRC-I) process solvent (PS) to obtain materials suitable for biological and chemical analysis. Those fractions eluted from TLC plates which were mutagenically active in the Ames/Salmonella assay were analyzed by gas chromatographic mass spectrometry (GCMS) for polycyclic azaarenes, polyaromatic primary amines (PAA) and carbazoles. In all materials tested, a strong correlation was observed between the concentration of PAAs in a given TLC region and the mutagenicity of that region in the Ames assay system. Conversely, azaarenes having 2--4 fused rings and carbazoles were present in both mutagenic and non-mutagenic TLC eluates. No PAAs were detected in mutagenically inactive TLC eluates. In comparison to the mutagenic tar fractions, the PS basic fraction contained relatively larger concentrations of 2- and 3-ringed components such as aminonaphthalenes and aminoanthracenes or aminophenanthrenes. The tar fractions, which were essentially devoid of aminonaphthalenes, had a higher average molecular weight and contained relatively higher concentrations of aminopyrenes.
TL;DR: The percent intergranular fracture and tensile ductility of iron tested at cathodic potentials in IN H2SO4 was found to depend primarily on the grain boundary sulfur concentration.
Abstract: The percent intergranular fracture and tensile ductility of iron tested at cathodic potentials in IN H2SO4 was found to depend primarily on the grain boundary sulfur concentration. Zone refined and vacuum melted iron with different bulk sulfur, oxygen, and nitrogen but similar carbon concentrations were evaluated. The grain boundary chemistry was measured by Auger Electron Spectroscopy and the fracture mode and ductility by uniaxial straining electrode tests at potentials of -0.60 to -2.0 V (SCE) in IN H2SO4. The tensile ductility, as measured by the total strain and reduction of area, of both irons decreased with increasing cathodic potentials. The fracture mode and ductility at a potential of - 0.6 V (SCE) was related to the grain boundary sulfur concentration with increasing sulfur resulting in an increasing percent intergranular fracture and a decreasing ductility. The fracture mode and ductility was not related to the grain boundary oxygen, nitrogen or carbon concentrations but large bulk nitrogen concentrations did promote cleavage and quasicleavage fracture.
TL;DR: Only recovery from fatigue in slow-twitch muscles was consistently and significantly affected (enhanced) by electric-field exposure, and it is suggested that the effect may be mediated secondary to an effect on mechanisms regulating muscle blood flow or metabolism.
Abstract: Neuromuscular function in adult male rats was studied following 30 days of exposure to a 60-Hz electric field at 100 kV/m (unperturbed field strength). Isometric force transducers were attached to the tendons of the plantaris (predominantly fast twitch), and soleus (predominantly slow twitch) muscles in the urethan-anesthetized rat. Square-wave stimuli were delivered to the distal stump of the transected sciatic nerve. Several measurements were used to characterized neuromuscular function, including twitch characteristics, chronaxie, tetanic and posttetanic potentiation, and fatigue and recovery. The results from three independent series of experiments are reported. Only recovery from fatigue in slow-twitch muscles was consistently and significantly affected (enhanced) by electric-field exposure. This effect does not appear to be mediated by field-induced changes in either neuromuscular transmission, or in the contractile mechanism itself. It is suggested that the effect may be mediated secondary to an effect on mechanisms regulating muscle blood flow or metabolism.
TL;DR: The level of exposure of laboratory animals to 60-Hz electric fields is commonly specified in terms of the unperturbed field strength present before the introduction of experimental subjects and their cages, and the actual perturbed electric fields experienced by an experimental animal were investigated.
Abstract: Rats were housed in two parallel rows of 12.4 cm x 25.1 cm x 10.2 cm high plastic cages resting on the lower electrode of a parallel-plate exposure system, and the actual perturbed electric fields experienced by an experimental animal were investigated. The most important results are: 1) Reducing the spacing between the exposure electrodes from 8.7 to 1.7 times the height of a singly exposed rat model, while maintaining a constant unperturbed field strength, resulted in a 15% increase in the electric field at the highest point on the surface of the body and a 10% increase in the short-circuit current of the model. 2) For multiple animal exposures, increases of 10% in both the field at the point of the body and the short-circuit current were observed when the electrode spacing was reduced from 8.7 to 2.6 times the height of a rat. 3) Plastic cages caused 1-6% reductions in the electric field at the surface of the body, except very near the cage walls, where enhancements of more than 20% were observed. 4) When 16 rats were simulataneously exposed, the short-circuit current, I/sub s/, of an individual subject of weight W (in g), that was surrounded onmore » all sides by other rats of weight W, was reduced from the short-circuit current, I/sub u/, measured with the same subject individually exposed as follows: during a 12 h light (sleeping) cycle, I/sub s//I/sub u/ = 1.00 - 0.0173W/sup 1///sup 2/; during a 12 h night (awake) cycle, I/sub s//I/sub u/ = 1.00 - 0.0136W/sup 1///sup 2/. (JMT)« less
TL;DR: In this article, a unique technique for simultaneous monitoring of thermally induced molecular and atomic species is used to investigate vaporization mechanisms for the rubidium analyte-tantalum furnace system used in atomic absorption analyses.
TL;DR: Male Wistar rats exposed to bituminous coal dust considered to have high potential for induction of coal workers' pneumoconiosis (CWP) developed lesions similar to simple CWP as described in human subjects.
TL;DR: In this article, the effects of cracks on glass leaching have been studied to determine to what degree the increase in the surface area of the glass caused by cracks might contribute to the overall leachability.