Radial and azimuthal dynamics of the io plasma torus

Thesis (M.S.) University of Alaska Fairbanks, 2015The moon Io orbits Jupiter emitting neutral particles from its volcanic surface. This emission is ionized and forms the Io plasma torus around Jupiter. The variation of conditions at Io and Jupiter lead to variations in the content of the plasma in the torus. Volcanoes on Io's surface erupt and change the rate of neutral input. Hot electrons (30-100 eV), whose abundances vary in azimuth, create highly ionized species. Radial variation in subcorotation velocities, velocities less than than that of the motion of the dipole magnetic field, creates shears while maintaining coherent radial structure in the torus. Poorly understood changes in plasma density circulate through the torus creating the anomalous System IV behavior that has a period slightly longer than the rotation of Jupiter's magnetic field. This thesis summarizes the research that has produced a two-dimensional physical chemistry model, tested several existing theories about subcorotation velocities, System IV variation, and hot electrons, and adopted new methods of Io plasma torus analysis. In an attempt to understand important dynamics, the thesis modeled differing scenarios such as an initialized two-peak structure, a subcorotation profile dictated by mass loading and ionospheric conductivity, and a critical combination of two populations of hot electrons that accurately mimics the observed System IV phenomenon. This model was also used to solve the inverse problem of determining the best fit for the model parameters, neutral source input rate and radial transport rate, using observations of density, temperature, and composition. In addition the thesis shows the need for multi-dimensional modeling and the results from its groundbreaking two-dimensional model

Superoxide Dismutase Activity within Caribou Serum as an Indicator of Copper Status

Copper concentrations measured in liver are the gold standard for evaluating the copper status of ruminants. For live ruminants, measuring copper status is problematic because serum copper concentrations fluctuate and are not consistently correlated to liver copper values. In an attempt to establish an accurate evaluation of copper status from serum in caribou, we examined the correlation between liver copper concentrations and superoxide dismutase (SOD), which uses the oxidation and reduction reactions of a bound copper ion in order to catalyze superoxide radicals. Our study focuses on SOD activity in the serum of 16 individual adult female caribou and compares that to known copper levels within the liver. Determining copper levels in ruminants has proven difficult and currently a true proxy to determine liver copper levels in a live animal is unknown

Copper Oxide Nanoparticles Impact Several Toxicological Endpoints and Cause Neurodegeneration in \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e

Engineered nanoparticles are becoming increasingly incorporated into technology and consumer products. In 2014, over 300 tons of copper oxide nanoparticles were manufactured in the United States. The increased production of nanoparticles raises concerns regarding the potential introduction into the environment or human exposure. Copper oxide nanoparticles commonly release copper ions into solutions, which contribute to their toxicity. We quantified the inhibitory effects of both copper oxide nanoparticles and copper sulfate on C. elegans toxicological endpoints to elucidate their biological effects. Several toxicological endpoints were analyzed in C. elegans, including nematode reproduction, feeding behavior, and average body length. We examined three wild C. elegans isolates together with the Bristol N2 laboratory strain to explore the influence of different genotypic backgrounds on the physiological response to copper challenge. All strains exhibited greater sensitivity to copper oxide nanoparticles compared to copper sulfate, as indicated by reduction of average body length and feeding behavior. Reproduction was significantly reduced only at the highest copper dose, though still more pronounced with copper oxide nanoparticles compared to copper sulfate treatment. Furthermore, we investigated the effects of copper oxide nanoparticles and copper sulfate on neurons, cells with known vulnerability to heavy metal toxicity. Degeneration of dopaminergic neurons was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, mutants in the divalent-metal transporters, smf-1 or smf-2, showed increased tolerance to copper exposure, implicating both transporters in copper-induced neurodegeneration. These results highlight the complex nature of CuO nanoparticle toxicity, in which a nanoparticle-specific effect was observed in some traits (average body length, feeding behavior) and a copper ion specific effect was observed for other traits (neurodegeneration, response to stress)

Age-related cellular copper dynamics in the fungal ageing model Podospora anserina and in ageing human fibroblasts

In previous investigations an impact of cellular copper homeostasis on ageing of the ascomycete Podospora anserina has been demonstrated. Here we provide new data indicating that mitochondria play a major role in this process. Determination of copper in the cytosolic fraction using total reflection X-ray fluorescence spectroscopy analysis and eGfp reporter gene studies indicate an age-related increase of cytosolic copper levels. We show that components of the mitochondrial matrix (i.e. eGFP targeted to mitochondria) become released from the organelle during ageing. Decreasing the accessibility of mitochondrial copper in P. anserina via targeting a copper metallothionein to the mitochondrial matrix was found to result in a switch from a copper-dependent cytochrome-c oxidase to a copper-independent alternative oxidase type of respiration and results in lifespan extension. In addition, we demonstrate that increased copper concentrations in the culture medium lead to the appearance of senescence biomarkers in human diploid fibroblasts (HDFs). Significantly, expression of copper-regulated genes is induced during in vitro ageing in medium devoid of excess copper suggesting that cytosolic copper levels also increase during senescence of HDFs. These data suggest that the identified molecular pathway of age-dependent copper dynamics may not be restricted to P. anserina but may be conserved from lower eukaryotes to humans

Method and apparatus for convection control of metallic halide vapor density in a metallic halide laser

An apparatus is disclosed in which a reservoir containing copper chloride is heated so that the copper chloride is maintained in a liquid form. The apparatus includes a means for flowing a buffer gas (which in the exemplary embodiment is neon) over the liquid copper chloride to provide a mixture of copper chloride vapor and neon above the liquid copper chloride. A conduit provides fluid communication between the reservoir containing the copper chloride vapor/neon mixture and the laser. The copper chloride vapor density in the laser is related to the liquid copper chloride temperature and the neon flow rate through the reservoir. In accordance with a further feature of the exemplary embodiment, neon is also provided directly to the laser in order to provide a further means of controlling the copper chloride vapor density in the laser

EVALUATION OF THE EFFECTIVENESS OF NATURAL ALTERNATIVE COPPER PRODUCTS AND LOW RATE COPPER FORMULATIONS AGAINST GRAPE DOWNY MILDEW IN ORGANIC VITICULTURE

The control of pathogenic fungi, especially downy mildew, represents the main problem in organic viticulture as only few fungicides, above all copper salts, can be used. As the copper causes problems of environmental impact, the Regulation EC n. 473/2002 fixed a ceiling on the use of copper compounds. Two years field trials were carried out in organic vineyeards to test the effectiveness, against Plasmopara viticola (Berk. et Curt.) Berl. et De Toni, of alternative copper products and low rate copper formulations, able to take place or to reduce copper quantities used. Amoung the alternative substances, in the first year of activity we examinated phito-stimulant and cuprics, while in the second year we examinated natural extracts, both vegetables and animals, and natural compound associates to the copper. The achieved results have underlined that, using the low rate copper formulations examinated, the total copper quantities were always less than 6 Kg copper per hectare, in accordance with the provisions of Regulation EC. The alternative products investigated have not guaranteed, instead, an adequate protection with high pressure od downy mildew. The trials confirm that the copper is indispensable for plant protection in organic farming, as it is not possible to replace it. We can only reduce the copper quantities used, at this point of time, but further studies are necessary to find appropriate alternative solutions able to control pathogenic agents in organic farming

Foam-machining tool with eddy-current transducer

Three-cutter machining system for foam-covered tanks incorporates eddy-current sensor. Sensor feeds signal to numerical controller which programs rotational and vertical axes of sensor travel, enabling cutterhead to profile around tank protrusions

Nanocomposites of metallic copper and spinel ferrite films: Growth and self-assembly of copper particles

Nanocomposites of metallic copper and iron oxides films have been prepared by RF-sputtering of pure CuFeO2 delafossite target. The films are made of copper and spinel ferrite crystallites of less than 10 nm in diameter. The content of metallic copper and the ferrite composition depend on the sputtering conditions. For the shortest substrate-target distances, films are made of copper and copper substituted magnetite with low copper content. The formation of the metallic and spinel phases is due to the loss of a small quantity of oxygen during sputtering. When annealed under inert atmosphere, nanometric copper particles located in the upper part of the film, move on the surface and grow due to coalescence phenomena. The particle motion can be stopped by small grooves allowing the self-assembly of copper particles

The expression of the gene for Azurin from Alcaligenes denitrificans in E. coli : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry at Massey University

Azurin is a protein which funtions in electron transport and has been found to bind copper when it is expressed in its native bacterial host. In this thesis the azurin from Alcaligenes denitrificans was used. This protein is 129 amino acids long with a molecular weight of 14. 600 dalions. The azurin coding gene from Alcaligenes denitrificans had previously been cloned into a plasmid which allows an E. coli expression system to be used. Azurin was purified from the E. coli hosts using the same procedures as for purifying copper-azurin from the native hosts but was found to remain apparently impure, according to spectrophotomctric data. Efforts to increase the production of the protein by using different expression systems and by refining the existing expression system failed to increase the apparent yield of copper-azurin. Efforts to refine the purification procedure also failed to increase the amount of copper-azurin that was purified. Various experiments were performed to demonstrate that azurin was expressed and processed correctly in the E. coli host. Protein was expressed in a copper-rich and copper-sparse environment. Copper-azurin was purified from the copper-rich environment, while very little copper-azurin could be extracted from the copper-sparse environment. The results described in this thesis suggest that when azurin from A. denitrificans is expressed in an E. coli host using standard media with no copper added, the predominant form of azurin produced in zinc-azunn. As mutants are going to made of this protein, conditions where the protein would bind only copper were required. The ideal conditions for this are still to be calculated but results from this thesis would suggest that copper concentrations in the region of 0.25 mM lead to 65% incorporation of copper. compared to 17% when no copper is added to the E. coli growth medium. E. coli cells were shown to grow with no apparent inhibition of growth in 3.0 mM of CuSO4. This concentration of copper in the growth medium may allow the production of a much higher ratio of copper-azurin compared to zinc-azurin than has been achieved so far

The Octarepeat Domain of the Prion Protein Binds Cu(II) with Three Distinct Coordination Modes at pH 7.4

The prion protein (PrP) binds Cu2+ in its N-terminal octarepeat domain. This unusual domain is comprised of four or more tandem repeats of the fundamental sequence PHGGGWGQ. Previous work from our laboratories demonstrates that at full copper occupancy, each HGGGW segment binds a single Cu2+. However, several recent studies suggest that low copper occupancy favors different coordination modes, possibly involving imidazoles from histidines in adjacent octapeptide segments. This is investigated here using a combination of X-band EPR, S-band EPR, and ESEEM, along with a library of modified peptides designed to favor different coordination interactions. At pH 7.4, three distinct coordination modes are identified. Each mode is fully characterized to reveal a series of copper-dependent octarepeat domain structures. Multiple His coordination is clearly identified at low copper stoichiometry. In addition, EPR detected copper−copper interactions at full occupancy suggest that the octarepeat domain partially collapses, perhaps stabilizing this specific binding mode and facilitating cooperative copper uptake. This work provides the first complete characterization of all dominant copper coordination modes at pH 7.4