Copper requirement

The most serious form of galvanic corrosion occurs in cooling systems that contain both copper and steel alloys. It results when dissolved copper plates onto a steel surface and induces rapid galvanic attack of the steel. The amount of dissolved copper required to produce this effect is small and the increased corrosion is difficult to inhibit once it occurs. A copper corrosion inhibitor is needed to prevent copper dissolution. 

We have, in this chapter, encountered a number of properties of solids. In Table 5-II, we found that melting points and heats of melting of different solids vary widely. To melt a mole of solid neon requires only 80 calories of heat, whereas a mole of solid copper requires over 3000 calories. Some solids dissolve in water to form conducting solutions (as does sodium chloride), others dissolve in water but no conductivity results (as with sugar). Some solids dissolve in ethyl alcohol but not in water (iodine, for example). Solids also range in appearance. There is little resemblance between a transparent piece of glass and a lustrous piece of aluminum foil, nor between a lump of coal and a clear crystal of sodium chloride. 

Concave curvatures are always found with calcium while straight lines are obtained in presence of copper. In Figures 3 and 4 the polymer concentration was expressed in mole of carboxyl groups in order to take into account the difference in the charge density between the samples. With copper (Figure 3) all the experimental phase separation points fall almost on a same line that is to say that the total concentration of copper required for precipitation depends only on... 

The use of copper required, as for other metals, the synthesis of novel proteins and controls over them to meet the requirements of equilibria (see Section 4.18). 

No documented report of fatal copper deficiency is available for any species of aquatic organism, and no correlation is evident in aquatic biota for the presumed nutritional copper requirements of a species and its sensitivity to dissolved copper (Neff and Anderson 1977). Extremely low copper concentrations (5.5 and 6.7 mg/kg DW) in whole bodies of 2 of 17 species of crustaceans from the Antarctic Ocean support the hypothesis that certain Antarctic species may show copper deficiencies or reduced metal requirements (Petri and Zauke 1993). 

Copper deficiency effects are reported in mink (Mustela vison) and domestic swine. Copper deficiency in mink, as judged by reduced survival, occurs by feeding rations containing the equivalent of 3.5 mg Cu/kg BW daily for a period of 50 weeks (ATSDR 1990). Swine, which seem to have higher copper requirements than mink, given low copper diets equivalent to 15 to 36 mg Cu/kg B W daily for 7 days have decreased hemoglobin, hematocrit, and growth rate (ATSDR 1990). 

Carlton, W.W. and W. Henderson. 1964b. Studies on the copper requirement of growing chickens. Avian Dis. 8 227-234. 

Elemental sulfur is present in most soils and sediments (especially anaerobic), and is sufficiently soluble in most common organic solvents that the extract should be treated to remove it prior to analysis by ECD-GC or GC-MS. The most effective methods available are (1) reaction with mercury or a mercury amalgam [466] to form mercury sulfide (2) reaction with copper to form copper sulfide or (3) reaction with sodium sulfite in tetrabutyl ammonium hydroxide (Jensen s reagent) [490]. Removal of sulfur with mercury or copper requires the metal surface to be clean and reactive. For small amounts of sulfur, it is possible to include the metal in a clean-up column. However, if the metal surface becomes covered with sulfide, the reaction will cease and it needs to be cleaned with dilute nitric acid. For larger amounts of sulfur, it is more effective to shake the extract with Jensen s reagent [478]. 

Naphthol has been reduced to 1-decalol using platinum,5 Raney nickel,6 and Raney copper.7 The reactions catalyzed by nickel and copper required elevated temperatures and pressure. The present procedure allows the preparation of substantial quantities of 1-decalol under much more convenient conditions and shorter reaction times. Previous methods5-7 require costly catalysts or high-pressure equipment and frequently result in a high degree of hydrogenolysis. The submitters have found that the present method is applicable to a wide variety of aromatic nuclei, some of which are listed in Table I. 

Basic copper carbonate is used as a pigment in paint and varnish as a fungicide for seed treatment as an insecticide in pyrotechnics and in the manufacture of other copper salts. The compound is also added in small quantities to animal and poultry feed to supply nutritional copper requirements. 

Employing thinner foil to dad the PC board reduces the amount of copper requiring removal through etching, and thus reduces the metals content of the waste streams (USEPA 1989). 

Klevay, L.M. Dietary Copper and Copper Requirements in Man, in Trace Element Metabolism Man and Animals (M. Kirchgessner, editor), p. 307. Institut fur Emahrungsphysiologie Technische Universitat Munchen, Freising-Weihenstephan, Germany, 1978. 

Finally, one of the first continuous ion-exchange plants installed used a weak-acid resin to recover copper from rayon-fibre spinning solutions. In the Bemberg or copper(II) ammonium process,357 the spinning takes place in an addic copper sulfate solution, and the fibre is then washed in ammonia solution. The wash water contains as much as 30% of the copper required for the spinning operation and its recovery is important in economic and environmental terms. The copper is extracted as the cationic amine complex by the weak-acid resin, and is then stripped from the resin with the acidic spinning solution. Zinc is recovered in a similar manner from vicrose rayon-spinning operations. 

Oxidation of copper requires a stronger oxidizing agent, such as HN03. 

Calculate the mass of copper required to produce 159 g of copper(n) oxide when heated in excess oxygen. 

For production of methylchlorosilanes, copper equivalent to about 10 per cent of the weight of the silicon is preferred as a catalyst. This may be added as a powder to the pulverized silicon and the mixture sintered in a hydrogen furnace, or it may be added in other ways. On a molar basis, this copper requirement represents 0.049 mole of copper per mole of silicon entering into the reaction, and all of it remains behind as the silicon is consumed. It Is at least theoretically possible to recover the copper after the reaction has run its course, but the limited recovery value of this small amount allows only the simplest methods to be considered. 

Figure 2. Synthesis of mature elastin fibers. Some evidence suggests the possibility for proforms to elastin that appear as the first products of translation. These products are cleaved to tropoelastin (27), which appears to combine with microfibrillar protein. Although post-translational events important to the synthesis of the microfibrillar protein have not been defined, it is clear that it is a major component on which is organized or assembled the profibrillar forms of elastin. Cross-linking is catalyzed by lysyl oxidase, a copper-requiring protein (30). Recent information on the elastin proteinase(s) involved in tropoelastolysis would suggest that proteolysis may also play a role in elastin fiber...

It is also of interest that when copper bound to serum proteins is added to cultures of minced aorta obtained from copper-deficient chicks, the amount of copper required for induction of lysyl oxidase is one-tenth to one-twentieth of that required when copper salts are added. Homogenizing the tissue or incubating it under or in the cold blocks the appearance of the enzyme. 

A number of copper requiring enzymes are located at the cell surface or are exported into the extracellular milieu. Examples of such secretory Cu-enzymes include copper requiring ferroxidases that fimction in iron transport (e g. ceruloplasmin, CP), enzymes for neurotransmission (peptidyl amidating enzyme and dopamine hydroxylase), an extracellular superoxide dismutase (SOD) that fimctions in antioxidant defense and enzymes for formation of connective tissue (lysyl oxidase), and pigments (tyrosinase) (reviewed in ). En route to their designated location, each of these enzymes passes through a specialized compartment of the late Golgi where copper insertion takes place. 

Delivery of Copper to the Cytosol The Copper Requiring Superoxide Dismutase Enzyme... 

The copper that is trafficked to the mitochondrial IMS for SODl and COX must first cross the outer membrane of the mitochondria. The mitochondrial outer membrane has large pores that could accommodate the transport of solutes and small molecules. However the molecular state of the copper as it transits the outer membrane and enters the IMS is not understood. Once copper does enter the IMS, it is known to be captured by two copper binding proteins that facihtate delivery of the metal to the copper requiring SODl and COX enzymes. These copper capturing molecules include the mitochondrial form of CCS (described above) and the copper carrier for COX, known as COX17. 

Laboratory data demonstrating copper limitation of marine phytoplankton are rare. It has generally been difficult to limit the growth rates of cultures by lowering the copper concentration in the medium, indicating a very low absolute copper requirement and/or a very effective uptake system in most species (Sunda and Huntsman, 1995c). If, as predicted, plastocyanin normally accounts for a major fraction of the copper quota of phytoplankton, a low-copper requirement would result from the known ability to replace plastocyanin by cytochrome c in the electron transport chain of the light reaction in a number of taxa. 

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