Search

Latent copper deficiency develops after 3 mo in patients receiving enteral feeding solutions with low copper levels. We examined whether a copper-rich enteral solution restores and maintains the level of copper in serum for a prolonged period. The study group consisted of 13 patients (eight males and five females). Commercial preparations, F2alpha and Lifelon-PZ, for enteral administration were used. F2alpha and Lifelon-PZ contain 1.6 and 0.13 mg/L, respectively, of copper. Serum copper levels were monitored in patients before and after administration of F2alpha, a copper-rich enteral solution, at the neurological ward of Nagoya Daini Red Cross Hospital. Four of the 13 patients received Liflon-PZ, a copper-poor enteral solution, before this trial. Blood samples were taken every month. The daily average copper dosage with F2alpha was 1.8 +/- 0.4 mg/d (1.0-2.4 mg/d). The copper level in the four patients who received Liflon-PZ was 10.5 +/- 5.5 micromol/L before this trial. The level rose to 18.9 +/- 3.6)mol/L 1 mo after the change to the copper-rich, F2alpha. The average serum copper level in the other patients before the start of enteral feeding was 15.3 +/- 5.0 micromol/L. The proper copper level was maintained with F2alpha in the long term. A copper-rich enteral preparation could easily restore and maintain serum copper levels for a prolonged period. A dose of 1.8 +/- 0.4 mg copper/d (1.0-2.4 mg/d) was sufficient for our patients.

Some properties of the three-phase mono-axial windings are reviewed from the point of view of both odd and even space harmonics. An interesting symmetry of the winding factors are demonstrated and used in order to synthesise windings with low copper and/or low space harmonic content.

Glucose at pathophysiological concentrations was able to accelerate copper-induced oxidation of isolated low-density lipoprotein (LDL) and whole serum. The efficiency of glucose was favored under the following circumstances: (a) when LDL oxidation was induced by low copper concentration, (b) when LDL was partly oxidized, i.e. enriched with lipid peroxides. The glucose derivative methyl-alpha-D-glucoside was ineffective on Cu2+-induced LDL oxidation, pointing out the essential role of the reactivity of the aldehydic carbon for the pro-oxidative effect. When LDL oxidation was induced by a peroxyl radical generator, as a model of transition metal independent oxidation, glucose was ineffective. Glucose was found to stimulate oxidation of LDL induced by ceruloplasmin, the major copper-containing protein of human plasma. Thus, glucose accelerated oxidation of LDL induced by both free and protein bound copper. Considering the requirement for catalytically active copper and for the aldehydic carbon, the pro-oxidative effect of glucose is likely to depend on the increased availability of Cu+; this is more efficient in decomposing lipid peroxide than Cu2+, accounting for acceleration of LDL oxidation. The possible biological relevance of our work is supported by the finding that glucose was able to accelerate oxidation of whole serum, which was assessed by monitoring low-level chemiluminescence associated with lipid peroxidation.

A 65-year-old gentleman presented with a history of abdominal distension and difficulty in walking 10 years after a Polya partial gastrectomy. Clinical history and neurological examination suggested an axonal sensory neuropathy. A computed tomographic scan of the abdomen showed a large afferent jejunal loop, and a hydrogen breath test confirmed small-bowel bacterial overgrowth secondary to the blind loop syndrome. Serological tests revealed low copper levels, which are a cause of a myeloneuropathy. The trace element deficiency occurred as a consequence of small-bowel bacterial overgrowth, and with antibiotic treatment of the bacterial overgrowth and copper supplementation his symptoms markedly improved.

Copper deficiency can delay flowering and plant maturity. However, the effect of copper deficiency on the rate of leaf emergence has not been quantified. We tested the hypothesis that low copper supply decreases the rate of leaf emergence of wheat (Triticum aestivum L. cv Gamenya). Copper foliar sprays are commonly applied to wheat. We examined the response of the rate of leaf emergence to a foliar application of copper sulphate.

The magnetization curves of copper-cobalt multilayers with thin copper layers show nonlinear slopes and remanence. We present here a phenomenological description of the antiferromagnetic coupling with a biquadratic term. These results are also compared with a more realistic model that takes into account the influence of cobalt pinholes through the copper layers.

A compact one-shot 3He cryostat has been fabricated for use of X-ray detector at a temperature of 0.4K. The cryostat employed two valves availably: one for controlling a charcoal adsorption pump, and the other for faciliating liquid helium handling. The use of two valves enabled us to decrease the amount of liquid helium including the transfer loss. Superconducting thin wires with a very low copper ratio were useful to generate a magnetic field of moderate strength, while suppressing the heat flow into the cryogenic region.

Biomass of spent P. griseofulvum was immobilized with various immobilizing agents. Among the different immobilizing materials screened, entrapment of cells in a naturally occurring protein with glutaraldehyde showed most favourable results for copper recovery. Entrapped cells of P. griseofulvum were successfully used even after 8 cycles of copper sorption. Glutaraldehyde concentration of 2% in the system and contact time of 60 minutes functioned ideally for optimum copper sorption. Presence of 10 ml of natural protein as compared to 5 ml in the immobilized system increased the copper removal by 1.3 fold. Both, blank beads and immobilized biomass proved efficient to recover the copper from solutions having low copper concentration. When blank beads, immobilized biomass and free biomass were repeatedly charged with copper bearing solution, after 8 cycles, immobilized biomass showed nearly 71 fold higher copper removal as compared to blank beads and 1.5 fold higher than free biomass. Under the experimental conditions immobilized system showed as high as 20.47 mg.g −1 copper loading as opposed to 15.51 mg.g −1 by free biomass. Challenging the system with high copper concentration of 63.5 μg.ml −1 (total 50.80 mg) showed 19, 56 and 44 % copper removal with blank beads, immobilized biomass and free biomass respectively. Free biomass reached saturation point with 38.10 mg of copper charging. Blank beads showed diphasic mode after 4 th cycle. In the initial 2 to 3 cycles, free biomass sorbed more copper as compared to immobilized biomass. After 3 cycles, immobilized biomass showed significant positive difference in copper sorption. In the 6 th cycle immobilized biomass gave 13 times more copper removal as compared to free biomass. Depending on the cycles of copper charging, the percent copper removal ranged from 2.3 to 94.0. The immobilized P. griseofulvum cells performed quantitative copper removal both from pure copper solution as well as from industrial effluent.

When the Savannah River Site in Aiken, South Carolina received a National Pollutant Discharge Elimination System permit containing very low copper and toxicity limits for an effluent-dependent stream, an innovative and cost-effective method to meet them was sought. The South Carolina Department of Health and Environmental Control mandated that compliance with the new limits be achieved within three years of the effective date of the permit. SRS personnel studied various regulatory options for complying with the new limits including Water Effect Ratio, use of a Metals Translator, blending with additional effluents, and outfall relocation. Regulatory options were determined to not be feasible because the receiving stream is effluent dependent. Treatment options were studied after it was determined that none of the regulatory pathways were viable. Corrosion inhibitors were evaluated on a full-scale basis with only limited benefits. Ion exchange was promising, but not cost effective for a high flow effluent with a very low concentration of copper. A treatment wetlands, not normally given consideration for the removal of metals, proved to be the most cost effective method studied and is currently under construction.

Different approaches are used to determine ideal ranges of intakes and threshold levels of safe intakes for nutrients. A consequence of this is that, for inorganic nutrients particularly, a safe level set by traditional toxicologic procedures might be compromised because it is inconsistent with physiologic observations and customary intakes and because the levels set may allow an inordinately narrow range of safe intakes above the upper limit of recommended intakes. This article used data from studies in animal models and in human volunteers to construct a provisional continuum of adaptive processes and pathophysiologic phenomena associated with a range of copper intakes extending from toxic to deficient to suggest an approach to establishing an acceptable range of intakes for copper that would address simultaneously the advisory and regulatory needs of nutritionists and toxicologists.

872 metal rubbings, each weighing about 10 micrograms, were taken from 364 gold objects from an unlooted Middle Sicin (ca. 1000 A.D.) Peruvian burial site and the gold, silver, and copper contents were determined by neutron activation analysis. Almost all objects have contents that are in the range: 35-65% gold, 25-45% silver, and 10-30% copper. Objects of similar style were more uniform in content; for example, the 28 bangles and 90 feathers from the main headdress have gold contents that range only from 46-56% and 37-45%, respectively. Some objects have contents markedly different from the rest of the objects; ear-spools, for example, have very low copper (1-6%) and high gold (56-75%). A high degree of control of the alloy content is evident, with each alloy mixture probably being chosen to have desired color and mechanical properties. The data indicate that very consistent 1.0-1.1 mixtures of gold:silver were used for 136 of the 142 feathers whereas gold:silver mixtures closer to 1.3-1.9 were used for most of the 96 bangles.

not Available.

A semi-empirical model describing the plane wave shielding effectiveness (SE) of metallized fabrics, both woven and non-woven, has been developed. The model incorporates the plane wave shielding theory of homogeneous metal foils, meshes, and thick perforated metal panels into a formulation for predicting the shielding effectiveness of metallized fabrics. Data is presented from 10 MHz to 17 GHz which shows the effects of surface resistivity, maximum fabric pore size, and fabric thickness on the shielding effectiveness of the metallized material. The model predictions are compared to measured data for low copper and high copper content nylon non-woven fabrics.

Copper is an essential co-factor for many enzymes, including cytochromes. The vast majority of plasma copper is transported bound to caeruloplasmin; the rest is bound to albumin, transcuprein and copper-aminoacid complexes. Copperhomeostasis is controlled by the liver, which synthesizes the copper storage/ transport protein apocaeruloplasmin, which forms caeruloplasmin on the addition of copper . Low plasma copper concentrations occur in patients with primary copper de¢ciency (Menke’s disease, non-Wilsonian copper movement disorder) or excess copper syndromes (Wilson’s disease), or secondary to disorders such as nephrotic syndrome, remitting acute leukaemia, some childhood iron de¢ciency anaemias or Kwashiorkor. Oliver et al. described two cases of very low plasma copper concentrations, and concluded that these were as a result of severe copper de¢ciency despite adequate daily copper intake. Both of these patients were given approximately 12% more copper, and the plasma copper concentrations remained more or less unchanged approximately 50 days later. After more than 50 further days, one of the patients eventually achieved a ‘satisfactory’ plasma copper concentration, while the other remained eiectively unchanged. However, the changes in the plasma copper concentrations for both patients seem to be strongly associated with the changes in caeruloplasmin concentrations throughout this period. This is in keeping with plasma copper concentrations being dependent on the production of its transport protein apocaeruloplasmin. The relationship between caeruloplasmin and copper has a correlation coe⁄cient of approximately 0.92, and, as a result, the caeruloplasmin concentration should always be kept in mindwhen interpreting plasma copper concentrations. Low plasma caeruloplasmin concentrations are more likely to result from issues relating to protein metabolism than from copper de¢ciency in these patients. Accordingly, the low plasma copper concentrations described are more likely to have been secondary to the low caeruloplasmin concentrations, and, if the latter increased, the total plasma copper concentration also increased. Thus, the real lesson from these two cases is that very low copper concentrations are not necessarily due to copper de¢ciency, and that it is essential to interpret low plasma copper concentrations in the light of the respective caeruloplasmin concentrations.

A low Copper (Cu) diet has been shown to produce alterations in placental Cu transport and fetal Cu stores. Cu deficiency has been associated with lipid deposition in the rat dam and fetal liver. In the presence of free fatty acids in the lumen of the small intestine, Cu absorption is decreased. We hypothesized that a high fat intake in the dam may worsen fetal Cu status and alter (Fe) deposits. Pregnant rats were fed normal diets in the first half of gestation and then assigned to one of the following 4 diets during the second half of gestation: normal Cu and fat: ND; high fat, normal Cu: HFNCu; normal fat, low Cu: NFLCu; and high fat, low Cu: HFLCu. One day before delivery, dams were anesthetized, maternal and fetal plasma and tissues obtained. Maternal, fetal, and placental weights were indistinguishable between diets. Dams plasma Cu and placental Cu were lower in both LCu diets than in ND or the HFNCu groups. However, fetal plasma Cu was similar in all groups. Both dam and fetal liver Cu were lower in the LCu diets than in the NCu diets. HFLCu fetal liver Cu was marginally lower than in the NFLCu group (4.02±0.77 vs. 4.86±0.94 μg/g, p≅0.05). Moreover the fetal/maternal liver Cu ratios were higher in the ND (4.12±0.44) and in the HFNCu(4.15±0.27) than in the NFLCu (1.84±0.31, p

We used 42 Angus bull calves (7 mo of age) to determine long-term effects of low Cu diets with or without supplemental Mo on performance, carcass characteristics, and Cu status. Twenty-two bulls were injected with 90 mg of Cu 28 d before weaning. After weaning, injected steers were fed a diet supplemented with 7.5 mg of Cu/kg of DM; control steers received no supplemental Cu. At the end of the 40-d receiving phase, supplemental Cu was reduced to 5 mg/kg of DM. One half of the steers in each group were fed 5 mg of supplemental Mo/kg of DM following the receiving phase. The growing phase lasted 196 d. Steers were then switched to a high concentrate finishing diet for 49 d. Copper injection increased ( P < .01) plasma Cu concentrations at weaning, and Cu-supplemented steers had greater ( P

The tolerance of triticale to low copper status in a soil adjusted to extremes of pH was determined in pots in a glasshouse experiment, and compared with the tolerance of its parent species, wheat and rye. Wheat plants were extremely sensitive to copper deficiency at all soil pH values and failed to produce heads or grain, whereas rye produced maximum yield irrespective of copper status or soil pH. Intermediate tolerance of triticale was demonstrated by virtue of the copper‐pH‐genotype interaction in that triticale was tolerant like rye at pH 5.0, but sensitive at pH 8.4 like wheat. Concentrations of copper were highest in rye and lowest in wheat, and decreased with increasing pH. The uptake of copper into grain and shoot was also lowest in wheat, and showed the same pH dependence as concentration. The appearance of copper deficiency symptoms on all plants which had low yields suggests that the major effect of pH in this system was on copper availability; the change in availability was, however, ...

Specimens of the oceanic decapod crustacean SysteUaspis debilis from the NE Atlantic were analysed for whole body concentrations of Cu, Zn, Fe, Mn and Cd. Concentrations of Zn, Fe, Mn and Cd decreased with increasing dry weight; Cu concentrations increased. Theoretical metabolic requirements for Zn, Mn and Fe in a decapod crustacean were estimated and are closely matched by the concentrations measured in S, debihs. The low copper concentrations may be explained by a low body content of haemocyanin.

Properties of seven dental amalgams (four conventional and three newly developed) are compared and statistically evaluated. Newly developed amalgams such as Tytin, Sybraloy, and Dispersalloy had low static creep, high compressive strength, and similar values for both diametral tensile strength and dimensional change in comparison with conventional amalgams such as Kerr Spheraloy, Caulk Spherical, Shofu Spherical, and Caulk 20th Century Micro Cut. The data for physical properties were evaluated statistically, and the amalgams were ranked according to the numerical position assigned to each property.

A syndrome of dental abnormalities in sheep is described. The features of the syndrome include excessive wear of deciduous incisor teeth, maleruption of permanent incisors associated with an osteopathy of mandibular bone, and the frequent formation of dentigerous cysts. Periodontitis of incisor teeth was present in some cases, and excessive incisor wear and premature tooth-loss were recorded in most sheep over 3 years old. The syndrome has been recorded on a number of farms in the lower part of the North Island, but was probably exacerbated in the Wairarapa district by inclement weather during 1977 and 1978. Excessive wear of the incisor teeth of cattle was also recorded on the same farms that had the problem in sheep. The presence of low copper levels, determined by liver and blood analyses from affected animals, is discussed in relationship to the complex, and possibly nutritional, aetiology.

Summary During a 98-day trial, eight groups of eight male weanling Texel x Friesian milk sheep lambs were fed the same hay and concentrates, the latter differing only in the contents of Cu, Zn, and Mo. At high (± 30 ppm) and moderately low (± 15 ppm) copper levels in the concentrates, additions of Zn (respectively 0, 150, and 340 ppm) and Mo (0 and 16 ppm) to the concentrates were studied with regard to effect on the accumulation of copper in the liver. At the higher copper level, the addition of 150 or 340ppm Zn resulted in a significant decrease of the Cu accumulation in the liver, while at a moderately low copper level the effect of these additions on the Cu accumulation was only slight. The two Zn doses given appeared to be equally effective in reducing the Cu accumulation. Additions of zinc did not increase liver and kidney Zn. The addition of Mo. resulted in higher levels of Mo in liver and kidney. At either copper level the addition of 16 ppm Mo was more effective in reducing the Cu accumulation in the liver than the addition of 150 or 340 ppm Zn. The additions of Zn and Mo, had no visible influence on the health of the lambs. This agrees with the finding that the blood parameters (determination of haemoglobin, haematocryt, protein, copper, zinc, enzymes) and the growth of the lambs were in the normal range. These results suggest that zinc may be a useful alternative to the somewhat toxic molybdenum as an additive to concentrates for sheep in preventing Cu intoxication.

Physical properties and microstructure of a single compositional high copper amalgam, into which tannin fluoride preparation was incorporated, was examined. A commercially available stannous fluoride incorporated low copper lathe-cut amalgam was applied as a control. Influence of immersion in water up to 12 months was also examined.

The copper tolerance of both adult plants and their seedlings, ofAgrostis tenuis from sites within and outside, but neighbouring the Parys Mountain mine (North Wales) were studied. Intensive sampling was carried out along a line starting from the mine boundaries to a distance of five miles away in the direction of the prevailing wind, and of two miles in an upwind direction. The test have shown that mine populations are very tolerant. In outside populations on soils with reduced of very low copper content the mean tolerance level of the seedlings is considerably higher than that of corresponding adult plants, while both show a gradual decrease in tolerance with distance from the mine. The gene flow moves in the direction of the prevailing wind transfering tolerant characters from the mine to the normal populations. The selective pressures on the toxic soil of the mine are quite strong and permit ± tolerant plants only, while on normal soils these pressures are not so severe, so that populations may be rather heterogenous regarding their tolerance towards copper.

Supported copper oxide on γ-alumina (2,4, or 10% Cu atoms per 100 A1) was subjected to cycles of reduction (by hydrogen) and oxidation (by oxygen). From the hydrogen consumed, from the water released and from the oxygen used in the oxidation step it was possible to deduce the molar fractions of Cu 0 , Cu 1+ and Cu 2+ present, as a function of the extent of reduction. At low copper loadings (2 or 4%) Cu 1+ is preferentially formed. The reduction to Cu 0 is thermodynamically favorable, but kinetically hindered. The role of the support and of the surface configuration is discussed.

Morphometric analyses of liver parenchymal cells were performed on male albino rats fed a semipurified diet supplemented with two levels of copper and zinc. These metals were administered in demineralized drinking water to four groups of animals at two levels. (1) 0.25 μgm Cu/ml, 2.5 μgm Zn/ml, and (2) 1.0 μgm Cu/ml, 10 μgm Zn/ml. Cadmium, also administered in the drinking water daily to rats at 17.2 μgm cadmium/ml, was given to one group of animals on each of the two semipurified diets. Two groups of rats were given laboratory chow plus 17.2 μgm Cd/ml for 71 days and for 280 days. Volume densities of all organelles diminished significantly when levels of copper and zinc were lowest. Surface densities of rough and smooth endoplasmic reticulum were significantly decreased. Higher levels of copper and zinc produced morphologic and morphometric parameters which fell just below those obtained for rats fed chow. Glycogen accumulation was highest when the levels of metal were low. Lipid inclusions were more frequent with semipurified diets than with chow. Hepatocytes from rats fed the semipurified diet with low copper and zinc plus cadmium demonstrated a significant increase in smooth endoplasmic reticulum compared to animals fed the semipurified diet alone. The smooth endoplasmic reticulum changed little when cadmium was given to rats receiving adequate copper and zinc. Smooth endoplasmic reticulum increased when diets included chow and cadmium whereas rough endoplasmic reticulum decreased. Cup-shaped and elongated mitochondria with longitudinal cristae appeared in hepatocytes from animals fed chow with cadmium. These were not seen with semipurified diets and cadmium.

A previous study of several different Ag−Sn, Ag−Cu, and Ag−Sn−Cu alloys revealed that some of these alloys were susceptible to mercury embrittlement. The present study was undertaken to determine the extent to which embrittlement of alloy particles in amalgam affects the strength of the material. Specimens of low copper amalgam (O), high copper admixed amalgam (D), and high copper single composition amalgams (S and T) were condensed into 2 mm×4 mm×15 mm molds using a pressure of 14 MPa. After aging the specimens for 7 days at 37°C, mercury was coated on each specimen either by electro-plating mercury or by immersion in mercury. In each method, mercury was applied for 15 s or 1 min. At 30 s after coating, each specimen was placed in a 3-point fracture fixture and immediately loaded at 0.25 and 2.54 mm/min until fracture occurred. As controls, specimens of each amalgam without mercury coating were also tested. Ten specimens per experimental condition were tested. Fractured surfaces were examined using a scanning electron microscope. Strength reductions as high as 60% for O amalgam, 44% for D amalgam, and 31% for T amalgam were found. Two observations suggest that embrittlement of unconsumed alloy particles is primarily responsible for the strength reduction: 1) the amalgams showing susceptibility to mercury embrittlement in the present study contain alloy particles of alloys that were shown to be susceptible to embrittlement in an earlier study, and 2) the amalgam S, which showed the least susceptibility to mercury embrittlement, contains unconsumed alloy particles of an alloy that showed no significant embrittlement in the earlier study. Experimental evidence supports the hypothesis that free mercury released during corrosion or aging of amalgam restorations can contribute to the weakening of these restorations.

The throwing power of the plating solution was shown to improve with a decrease in the concentration of the copper sulphate and an increase in the concentration of sulphuric acid. With a low copper sulphate content, however, the cathodic current efficiency fell, hydrogen evolution occured and powdery deposits formed. Good results could be obtained with about 60 (g CuSO 4 ) l -1 and 150 (g H 2 SO 4 ) l -1 . The presence of sodium chloride in the bath affected the surface appearance, structure, microhardness and internal stress. An addition of about 50 (mg Cl - ) l -1 seemed to be the optimum and permitted an increase in the maximum microhardness but did not raise the internal stress.

Lesions were found in the pancreas of clinically normal cattle of low copper status. In comparison with the pancreas of cattle with normal hepatic copper reserves, the abnormalities were an increase in the dry matter content and reduction in the concentrations of protein and copper in the wet tissue. Cytochrome oxidase activity and protein-to-RNA ratio were also reduced. Histologically, there were defects in acinar basement membranes, splitting and disorganization of acini, cellular atrophy and dissociation, and stromal proliferation. The pancreatic ductular system did not show atrophy or disorganization.

Copper uptake by and toxicity to Saccharomyces cerevisiae Hansen is greatly enhanced by glucose. Uptake and toxicity are markedly reduced at low temperature (1–2 °C) and the enhancement by glucose abolished. Energy dependent transport of copper is indicated but further investigation was precluded by high toxicity of very low copper concentrations.

Chromatographic properties of copper-binding proteins (copper-containing metallothioneins) induced in rat liver and kidney by the injection of either copper in the liver and kidney or cadmium in the kidney were compared with those of metallothioneins, with low or no copper content, induced by the injection of cadmium or zinc in the liver both on a Sephadex G-75 column and on a DEAE Sephadex A-25 column. The copper-containing metallothioneins were eluted at a slightly slower rate on a Sephadex G-75 column and at a higher buffer concentration on an anion exchange column than the metallothioneins with low or no copper content regardless of the inducing metals, copper or cadmium. The different chromatographic properties of the metallothioneins with high and low copper contents may be explained by the more compact conformation of the proteins with high copper contents than those with low or no copper contents and by the changes of electrostatic charge with coordination by copper.

The bending creep of six different dental amalgams was continuously measured up to 30 days under different static loads. All six amalgams induced creep rupture within 30 days under 9 kgf of static load and some of them did under the lower static load. The high copper amalgams resisted for a longer period of time compared to the low copper amalgams. The admixed high copper amalgam had the highest creep value at rupture under the same load, which indicates that this amalgam is more flexible under continuous loading than the other amalgams. The rupture time was approximately proportional to the reciprocal of the creep rates and the rupture time drastically increased as the creep rate decreased. This result basically explains and supports the previously reported correlation between the compressive creep during a specific period of time and the marginal fracture of amalgam restorations.

The use of hair as an index of mineral status has received some criticism despite its wide use in research and its wider use as a diagnostic tool. This study evaluated the effect of dietary copper and sodium intake upon the concentration of these minerals in hair. Forty-eight Long-Evans rats were divided into 3 groups of 16 at weaning and fed one of three levels of copper; 1) low copper (LC), 2) marginal copper (MC) or 3 mg Cu/Kg feed, and 3) adequate copper (AC) or 8 mg/Kg feed. Rats were fed these diets ad libitum for 6 months. At day 100, half of the rats received 5% NaCl for 1 week followed by 1% NaCl for 11 weeks as drinking water. The other half received deionized-distilled water as drinking water. Results revealed that rats fed the AC diet had higher (p≤0.001) hair copper concentrations than rats fed the MC and LC diets. Rats fed the MC diet had higher (p≤0.001) hair copper concentrations than rats fed the LC diet. Higher hair sodium concentrations were found in rats consuming saline compared to rats consuming deionized-distilled water (p≤0.05). These results support the use of hair as a measure of mineral intake for populations.

The effect of mercury to alloy ratio on the hardness of high copper amalgam restoration at the margin and center of the amalgam was examined. The hardness of amalgams made from lower mercury to alloy ratio was smaller than that prepared by the manufacture's recommendation. With higher mercury to alloy ratio, the resultant hardness was smaller, and differed from alloy to alloy. Some single compositional high copper amalgams had markedly smaller hardness than others, including low copper amalgams. Regardless of the alloy type and mercury to alloy ratio, the hardness at the margin of the amalgam was apparently smaller than that of the canter. This was more prominent in high copper amalgams.

Studies concerned with the sub-lethal aspects of the toxicity of copper to the mussel have, in many cases, been compromised through the use of static experimental systems (see Davenport & Redpath (1984) for review). Manley, Gruffydd & Almada-Villela (1984), using a through flow system, reported a significant reduction in shell growth at a concentration of 10 μg I-1 added copper with recovery after metal addition had ceased. Strömgren (1982) investigated the effects of a series of concentrations of the metal (amongst others) on Mytilus, but there are discrepancies between his results and the work of others which have been fully discussed elsewhere by Davenport and Redpath.

Analyses of the ampharetid polychaete Melinna palmata have shown that this species consistently contains a high concentration of copper. The related species Melinna cristata also has a high copper content but Ampharete acutifrons and Amphicteis gunneri have low copper contents. M. palmata usually contains copper in concentrations in excess of 600 μg/g (dry weight) and often above 1100 μg/g; much of this copper is embodied in the branchiae which have concentrations of 0·4–1·2% copper and, although these organs account for only 3–4% of the dry body weight, their copper content represents 30–40% of the total body burden. X-ray microanalysis shows the copper in the branchiae to be concentrated in special epidermal cells. The function of the copper in these cells does not appear to be associated with detoxication, luminescence or an antifouling mechanism but feeding trials have shown the branchiae of Melinna palmata, but not of Ampharete acutifrons, to be distasteful to certain small fish. Thus it is thought the copper may reduce the palatability of the tissues and is accumulated by Melinna palmata as a chemical defence against predation.

In an earlier investigation by the authors concerned with the production of semiconducting dice of ZnS, it was shown that all their samples were contaminated with trace concentrations of copper, and the lowest resistivity ( approximately 102 ohm cm) could be obtained by heating the crystalline material in molten zinc containing 1% Ga and 1/2% Al. The broadband photoluminescence of all the samples used in these conductivity studies has now been measured, and identified as a self-activated emission. At low copper concentrations the emission shifts to higher photon energies on cooling to 80K, but with copper concentrations exceeding 0.85 ppm the emission shifts to lower energies on cooling. A model is suggested to explain this effect. It involves recombination from distant donors to complex centres consisting of (GZn+-AlZn3+) A-centres associated with CuZn+ copper green centres at low copper concentrations, and with (CuZn+-CuI+) copper blue centres at higher concentrations. The model can also explain why heating in Ga+Al is particularly effective in reducing the resistivity. Similar effects occur in ZnSe, where the model can explain why excitonic emission is observed in dice heated in zinc containing 1% gallium.

Seven western states in the U.S. were surveyed to evaluate the frequency of supplement intakes for calcium, iron, and zinc for an adult population. Of the 2451 adults who completed and returned the questionnaire, there were 1643 supplement users. Thirteen percent of these indicated use of a calcium supplement, 11% an iron supplement, and 12% a zinc supplement. More females than males were mineral supplement users. The data indicated that there is a potential for low copper status due to some levels of zinc and calcium supplementation; low zinc status due to some levels of iron supplementation; and low iron status due to some levels of calcium supplementation. The reasons cited for mineral supplement use related to a number of misconceptions as to the physiologic role of calcium and zinc in particular. The use of these supplement were for undocumented reasons, and at some of the intake levels consumed, users may be detracting from their nutritional status via the potential interaction among the minerals.

Microstructure of commercial dental alloys and their amalgams were studied primarily by x-ray diffraction, optical metallography, scanning electron microscopy, and x-ray energy dispersive spectroscopy. X-ray diffraction revealed more phases than normally reported in these materials. Presence of new phases was discussed and their formation mechanism understood. Some phases having interacting 2θ° values with others were properly identified. Both new and conventional dental alloys and their amalgams, namely Tytin, Sybraloy, Dispersalloy, Kerr Spheraloy, Caulk Spherical, Shofu Spherical, and Caulk 20th Century Microcut were used to complete the investigation.

Eight soil tests for plant-available copper were used on twenty English soils of moderate to low copper status. The ability of these tests to predict plant copper uptake, tested in a pot trial, was compared using multiple regression analysis including other soil factors such as pH, organic matter and clay content. The EDTA soil test was found to give the best prediction of plant uptake from a regression equation including EDTA extractable soil copper, pH, free Mn and Fe oxide, clay and organic matter content.

SUMMARY An important factor in plant availability of copper is its anomalous binding to soil humic substances, for which aggregation phenomena have been implicated. Two alternative models of copper-induced humate aggregation are theoretically explored to characterize binding behaviour. In the first model the copper modifies the humic acid so that it self-associates indefinitely. Copper binding is found to be dramatically enhanced, except at the very low concentrations corresponding to copper-deficiency. In the second model bivalent copper forms bridges between different humate molecules to yield an array of large cross-linked complexes. In the latter cross-linking model, binding of copper is markedly enhanced at low copper concentrations, a behaviour still found when only relatively few sites sterically permit cross-linking. The cross-linking model accounts, at least in part, for the low availability and immobility of copper in some problem soils and is consistent with several items of experimental evidence.

From glasshouse experiments it seems probable that the more effective utilisation of nitrogen in the synthesis of protein with which copper may be associated is the reason for the increased severity of copper deficiency observed when phosphate is applied to oats growing on a peat medium of low copper content.

Both kinetic and equilibrium properties of DNA denaturation in the presence of copper(II) cation were studied by using optical techniques. Equilibrium properties of the reaction, measured in terms of Tm, the melting temperature, were shown to depend not on the overall but on the equilibrium concentrations of the species involved. Although Tm did increase with DNA concentration at low copper(II) concentrations, under similar conditions an increase in Tm with increasing copper(II) concentration was not observed. The kinetic properties of the reaction, characterized by the terminal relaxation time, were also found to depend on equilibrium concentrations of reactants. Application of standard methods of relaxation kinetics led to the proposal of a mechanism for copper(II)–DNA complex formation. That mechanism involves the rapid binding of two copper(II) ions to a reaction site on the polymer, followed by a slow, rate-limiting, first-order decay of the complex to the denatured state.

The blood copper of normal sheep from the Institute flock at Cambridge was studied over the period October-April for three lambing seasons and showed no changes characteristic of pregnancy; in contrast to the behaviour of human beings and possibly sheep of low copper status. What changes there were took place in both pregnant and nonpregnant sheep, did not reflect the transfer of copper to the foetus and appeared to be due to extrinsic factors.Comparison of the blood copper of the lamb with that of its dam for four lambing seasons showed that it was a changing quantity at birth, being lower in the foetus, variable a few hours after birth and higher some days later than in the ewe.The blood copper of suckling lambs was studied from birth in February-March until June, for three seasons. There tended to be high values in the first 1 or 2 weeks of life, which decreased in the course of approximately 10 weeks.

An initial study has been made on the abundance and mutual behavior of copper, zinc, and lead in a certain type of sulfide concentration. Fourteen sample deposits, some from each of Australia, Canada, and Eire, have been found to show, in addition to similarities in environment and mineralogy, several chemical affinities. Among these are a persistently low copper content, a poor correlation between copper and zinc, on the one hand, and quite a good correlation between lead and zinc, on the other; a similarity of mean lead: zinc ratios throughout the group; and, lastly, a marked consistency, throughout the group of deposits, in the behavior of the ternary group copper-zinc-lead. Although no definite conclusions concerning genesis are drawn, the possible significances of some of the compositional features are discussed. In addition, the mutual behavior of the copper, zinc, and lead in the deposits is compared with that noted by E. B. Sandell and S. S. Goldich in some North American igneous rocks The mutual ...

Summary Frozen cream of 40 per cent or more fat is an important product of commerce in the dairy industry of the United States. Its use is largely confined to the populated centers although it may originate elsewhere. Upon pasteurization in the ice cream mix the butterfat oils off considerably and must be emulsified by means of homogenizers or viscolizers. Due to this oiled off condition the whipping ability of the ice cream is adversely affected and some egg yolk product is usually used to restore the overrun. The removal of the fat globule membrane by the pressure of freezing and the failure to restore this membrane to the original fat are the causes of the poorer whipping of the ice cream mixes containing frozen cream. The reduction of acid in ice cream mixes containing frozen cream to approximately 0.10 per cent also restores overrun. The inferior keeping quality of much of the frozen cream often precludes its use as the sole source of fat in ice cream. Pasteurization of the cream to temperatures above 170° F., low copper content, low storage temperature (0 to – 15° F.) in proper containers and homogenization at the heating temperature all aid in enhancing the keeping quality. Thus it may be possible to use a larger quantity in ice cream. Eh determination of pasteurized cream may prove an aid in predicting the keeping quality of the product when frozen. Oxidized flavor in copper-catalyzed cream, which is the chief flavor defect, is caused by oxidation of the phospholipid fraction of the fat globule membrane.