Effect of copper

The important commercial feature of these juices, especially significant with blackcurrant and tomato juices, is their ascorbic acid (or vitamin C) content, of which loss by oxidation is known to be accelerated both by heat and by metal (particularly copper) contamination. The effect of copper has been carefully investigated for pure ascorbic acid", and more recently ascorbic acid in blackcurrant juice and model systems. There are, however, oxidation inhibitors of different kinds (which may themselves be heat-sensitive) present in various fruits, which give differing results. The presence of metals will also affect flavours", may cause discoloration, and may give rise to clouding effects, as in apple juice. ... 

The effects of copper ions on the process were elucidated as follows. It was known that copper ions inhibit aconitase activity. 

In these particular experiments it proved impossible to investigate the effect of copper concentration on the catalytic activity of alloys free of the hydride phase. Figure 10 69, 64a, 65) illustrates the changing values of the recombination coefficient on nickel-copper alloys related to the composition of the alloy at room temperature. The small amount of copper introduced into the nickel already distinctly decreased the catalytic ac-... 

Baranowski [680] concluded that the decomposition of nickel hydride was rate-limited by a volume diffusion process the first-order equation [eqn. (15)] was obeyed and E = 56 kJ mole-1. Later, Pielaszek [681], using volumetric and X-ray diffraction measurements, concluded from observations of the effect of copper deposited at dislocations that transportation was not restricted to imperfect zones of the crystal but also occurred by diffusion from non-defective regions. The role of nickel hydride in catalytic processes has been reviewed [663]. 

Sabater S, Navarro E, Guasch H (2002) Effects of copper on algal communities at different current velocities. J Appl Phycol 14 391... 

Serra A (2009) Fate and effects of copper in fluvial ecosystems the role of periphyton. PhD Thesis, University of Girona... 

Guasch H, Paulsson M, Sabater S (2002) Effect of copper on algal communities from oligotrophic calcareous streams. J Phycol 38 241... 

Soldo D, Behra R (2000) Long-term effects of copper on the structure of freshwater periphyton communities and their tolerance to copper, zinc, nickel and silver. Aquat Toxicol 47 181... 

The effect of copper(II) is essentially similar to that of iron(Ill). In reaction (48) copper(I) is formed which results either indirectly by reaction (49) or directly by reaction (50) in the reduction of a peroxydisulphate ion... 

The effectiveness of copper(II) catalyst can be shown by the following values of the rate coefficient. In the absence of air... 

Similar structural changes of the copper layer on ruthenium are observed for the ethane hydrogenolysls reaction shown In Figure 10 (12). The effect of copper at low coverages Is to simply block active ruthenium sites on a one to one basis with three dimensional cluster growth occurring at roughly a third of a monolayer. 

Esterbauer et cil. (1992) have studied the in vitro effects of copper on LDL oxidation and have shown that there are three distinct stages in this process. In the first part of the reaction, the rate of oxidation is low and this period is often referred to as the lag phase the lag phase is apparently dependent on the endogenous antioxidant content of the LDL, the lipid hydroperoxide content of the LDL particle and the fatty acid composition. In the second or propagation phase of the reaction, the rate of oxidation is much faster and independent of the initial antioxidant status of the LDL molecule. Ultimately, the termination reactions predominate and suppress the peroxidation process. The extensive studies of Esterbauer et al. have demonstrated the relative importance of the endogenous antioxidants within the LDL molecule in protecting it from oxidative modification. 

Sauve S., McBride M.B., Norvell W.A., Hendershot W.H. Copper solubility and speciation of in situ contaminated soils Effects of copper level, pH and organic matter. Water Air Soil Pollut 1997 100 133-149. 

L. Landner and R. Reuther (eds.) Metals in Society and in the Environment. A Critical Review of Current Knowledge on Fluxes, Speciation, Bioavailability and Risk for Adverse Effects of Copper, Chromium, Nickel and Zinc. 2004... 

Bang, K. S., Familton, A. S. and Sykes A. R. (1990). Effect of copper oxide wire particle treatment on establishment of major gastrointestinal nematodes in lambs . Research in Veterinary Science, 39(2), 132-137. 

Burke, J. M., Miller, J. E., Olcott, D. D., Olcott, B. M. and Terrill, T. H. (2004). Effect of copper oxide wire particles dosage and feed supplement level on Haemonchus contortus infection in lambs . Veterinary Parasitology, 123, 235-243. 

Effects of copper-based fungicides on crop growth, the environment and food safety... 

Certain antioxidants also offer protection against the deleterious effects of copper and manganese, and are thus termed copper inhibitors. 

Lipman CB, Burgess PS (1914) The effects of copper, zinc, iron and lead salts on ammonification and nitrification in soils. University of California Publications in Agricultural Science 1 127-139... 

The above transformation takes place via the catalytic effect of copper (I), which generated the corresponding carbenoid from a-diazo-p-keto esters. These Cu-carbenoides react with the thiocarbonyl group of thioamides, after cyclocondensation to afford 2-aryl-l,3-thiazole-5-carboxylates (Scheme 18).40... 

Superoxide-dismuting activity of copper rutin complex was confirmed by comparison of the inhibitory effects of this complex and rutin on superoxide production by xanthine oxidase and microsomes (measured via cytochrome c reduction and by lucigenin-amplified CL, respectively) with their effects on microsomal lipid peroxidation [166]. An excellent correlation between the inhibitory effects of both compounds on superoxide production and the formation of TBAR products was found, but at the same time the effect of copper rutin complex was five to nine times higher due to its additional superoxide dismuting capacity. 

Effects of copper on representative terrestiial plants and invertebrates... 

Adverse effects of copper deficiency can be documented in terrestrial plants and invertebrates, poultry, small laboratory animals, livestock — especially ruminants — and humans. Data are scarce or missing on copper deficiency effects in aquatic plants and animals and in avian and mammalian wildlife. Copper deficiency in sheep, the most sensitive ruminant mammal, is associated with depressed growth, bone disorders, depigmentation of hair or wool, abnormal wool growth, fetal death and resorption, depressed estrous, heart failure, cardiovascular defects, gastrointestinal disturbances, swayback, pathologic lesions, and degeneration of the motor tracts of the spinal cord (NAS 1977). 

Table 3.4 Effects of Copper on Representative Terrestrial Plants and Invertebrates Organism, Copper Concentration or Dose,...

---