Copper indicator

Some unnatural amino acids have been designed with this metal-chelating property in mind. For instance, bipyridylalanine (BpyAla, 27) has the bipyridyl group that chelates most transition metal ions and has been successfully incorporated into proteins in E. coli BpyAla was shown to reversibly bind copper ions when incorporated into T4 lysozyme, but a tyrosine in the same location was unable to bind copper, indicating that BpyAla is useful to coordinate copper ions to a protein of interest. 

Porphyry Copper Indicator Minerals (PCIMs) in glacial till samples from the giant Pebble porphyry Cu-Au-Mo deposit exploration significance... 

The data for copper indicates that contamination may have come from the platinum crucibles since similar concentration trends were noted for both covered and uncovered crucibles. Under the chosen ashing conditions, vanadium and molybdenum were apparently consistently volatilized. 

Results obtained for four samples of BCS copper alloys are shown in Table 5. All the results indicate good agreement with certified values. The results obtained for copper indicate that in favourable cases it is possible to obtain satisfactory results for major alloying components. The excellent results which can be obtained for the analysis of large percentage amounts of copper is further confirmed by the work of Sattur [6], whose results for five copper-based alloys are shown in Table 6. 

The two peaks for copper indicated that it was present in both Cu(I) and Cu(ll) forms, although Cu(ll) was the expected oxidation state. This may be explained by considering the exposure to x-rays under ultra-high vacuum conditions, which is known to reduce Cu(ll) to Cu(l). To prove this hypothesis, a series of experiments with increasingly short exposure times were performed on fi eshly prepared samples of the postmodified material and it was noted that reduction was observed even for very short exposure times. Fig. 3 presents an example of the effect of x-ray exposure on the relative proportion of Cu(l). In addition to a shift in the peaks to lower binding energy, there is also a reduction in the intensity of the satellite peaks, which are both indicative of a loss of Cu(Il). Therefore, it was concluded that the presence of two apparent oxidation states in the postmodified MCM 41 was a function of the analysis conditions rather than a fimdamental property of the material. 

Copper helps form red blood cells and connective tissues. Copper is a cofactor enzyme that initiates metabolic reactions in the body. Copper is necessary to produce norepinephrine and dopamine (neurotransmitters). Copper is absorbed in the intestine. Foods rich in copper are shellfish (crabs and oysters), liver, nuts, seeds (sunflower, sesame), legumes, and cocoa. Copper deficiency results in anemia, causes decreased hair and skin pigmentation, decreased white blood count, intolerance to glucose, and mental retardation in young patients. Excess serum levels of copper indicate Wilson s disease, which results in the accumulation of copper in the liver, brain, cornea, and kidney. 

P. W. Alexander, P. R. Haddad, and M. Trojanowicz, Potentiometric detection in ion chromatography using a metallic copper indicator electrode, Chromatographia, 20,179,1985. 

Copper strip corrosion. This determines the ability to tarnish clean copper, indicating the presence of any corrosive sulfur compounds. 

A metallic electrode of llte Itrsl kind is a pure metal electrode in direct equilibrium with its cation in solution. Here, a single reaction is involved. For example, for a copper indicator electrode, we may write... 

Studies investigating the effects of pesticides on crustaceans should be of high priority. Crustaceans are very important consumers and prey in various aquatic systems and there are delicate relationships between crustacean plankton prey and fish predators in the pelagic zone that can and have been shown to be disturbed. It is known that pesticides are present in surface waters and it is especially urgent to study the effects of insecticides on freshwater species and species that are present in estuaries and coastal waters with high risks of contamination due to vicinity to the sources. In acute toxicity tests crustaceans were much more (often 10-times more) sensitive to insecticides than fish (Maltby et al. 2005), and some of the chemicals probably affect behaviors at very low concentrations. As there are very few studies done on pesticide effects on crustacean chemoreception it is not possible to compare their sensitivity with fish, but it is likely that there are differences. The few crustaceans studied concerning effects of copper indicate that they are less sensitive to the metal compared with fish. 

The anticorrelation of nickel and copper indicates that these elements reside in different minerals. Nickel is closely correlated with magnesium (not shown) which indicates that it resides in pyroxene, whereas copper is correlated with zinc (not shown) and both elements may occur in sulfide minerals. 

---