Proportion Of Cu Research Articles

Layer Structures of CuxAg1-xI Crystals

X-ray diffraction studies were made on layer structures in the quasi-binary system CuI–AgI and their structural changes were investigated by standing them at room temperature and by heating. The proportion of Cu to Ag in a crystal was determined by the atomic absorption method. The following facts were revealed. The Cu x Ag 1- x I crystals have faulted 2 H structures, which often coexist with long-period polytypes, in the composition range 0< x <0.025, the 4 H structure in 0.025≤ x ≤0.034, the 4 H structure immediately after growth in 0.061≤ x ≤0.092 and the 3 R structure (the zincblende-type structure) in 0.148≤ x ≤0.277. The 4 H structure in the range 0.061≤ x ≤0.092 changes to twins of the 3 R at room temperature and this structural change occurs earlier with increasing x value. The 3 R structure is stable at high temperatures below 146°C over the range x ≥0.025. Reduced lattice parameters of the layer structures decrease with the increase of Cu concentration and the Cu ion is substituted for the Ag ion.

Intracellular distribution of copper in the liver of normal and copper loaded sheep

Thirteen sheep were dosed repeatedly with copper sulphate in order to induce chronic copper poisoning. Twelve similar sheep acted as controls. Three dosed sheep were killed before haemolysis, six at haemolysis and four after cessation of the haemolytic crisis. The subcellular distribution of Cu, Zn, Fe and lysosomal marker enzymes was investigated in the livers of normal sheep and copper loaded sheep. In control sheep the highest concentration of Cu was in the nuclear fraction. Copper loading increased the concentration of Cu in all fractions. The proportion of Cu in the nuclear fraction continued to increase while that in the heavy mitochondrial fraction decreased. Significant increase in lysosomal enzymes along with electron microscopic studies on pellets of fractions indicated: (a) proliferation of lysosomes, (b) possible localisation of Cu in lysosomes, and (c) sedimentation of the denser lysosomes on N and MH fractions in test sheep with the majority being in the N fraction. Thus the increase in Cu observed in the N fraction is at least partly due to the storage of Cu by lysosomes which sediment with the heavier nuclei. The excessive deposition of Cu in lysosomes and nuclei may lead to cell damage. With increase in hepatic Cu concentration the proportion of Zn and Fe in the cytosol decreased.

Activated Sintering of Tungsten-Copper Contact Materials

Nickel or cobalt additions were made to W–Cu compacts to determine whether the substitution of Co for Ni would improve their sintering characteristics and their properties as contact materials. For alloys with small proportions of Cu, Co was more effective in promoting sintering than Ni, whereas in those alloys with a high Cu content neither addition affected the sintering process. Despite their different sintering characteristics, no significant differences were detected in the contact angles of the liquid phases in W–Cu, W–Cu–Co or W–Cu–Ni alloys. The improved sintering of low-Cu alloys containing Co appears to be related to the formation of W6Co7 intermetallic compound on the surface of the W particles.

Trace element supply to ruminants in the German Democratic Republic. 2. Supply of copper

The supply of copper to ruminants as influenced by and depending on the geological origin of soils was investigated in different parts of the GDR by using the hair test. Red clovers (meadow clover and field clover) were used as indicator plants. The following results were obtained: Data on the Cu content of clovers grown on soils of the same geological origin were found to correlate with r = 0,81. After eliminating the effects of Cu antagonists resulting from industrial pollution it was possible to establish numerical relations (B = 0.39 and B = 0.89) between the relative values (specific for the particular location) for the Cu content of the indicator plants and the percentage of cows suffering from Cu deficiencies (6.0 and 5.0 ppm Cu in hair). The lowest percentages of Cu supply to the ruminants (established on the basis of the Cu content of red clovers) were found on diluvial sandy soils, glacial loams and peat and bog soils whereas the highest percentages of Cu were found on weathered soils (of phyllite, gneiss, shell limestone, red marl soils and porphyry). Secondary Cu deficiencies in ruminants may arise, independent of the geological origin of the soil material, in places exposed to the main direction of the winds from major industrial areas (emission of SO2, Cd and Mo). Due to primary and/or secondary deficiencies the supply of Cu to ruminants in various locations (syenite, granite, red sandstone, gneiss, loess; peat soils, diluvial sandy soils) may be insufficient. A detailed description is given of areas where Cu deficiency is likely to occur and recommendations are given on how to use mineral mixtures containing a high proportion of Cu (1.00 g Cu per kg).

Hepatic copper-and zinc-binding proteins in ruminants. 1. Distribution of Cu and Zn among soluble proteins of livers of varying Cu and Zn content.

1. A metal-binding fraction with a molecular weight of about 12000 in calf and sheep liver has been characterized as a metallothionein-like protein.2. The combined concentrations of copper and zinc in the fraction (as μg/g liver) are a direct function of liver Zn concentration.3. The relative proportions of Cu and Zn in the fraction are dependent on the Cu: Zn ratio in the liver.4. These findings may be relevant to the mutual interaction between Cu and Zn.

TIME CULTURE. AN IMPORTANT VARIABLE IN STUDYING IN VIVO RADIATION-INDUCED CHROMOSOME DAMAGE IN MAN.

SummaryStudies have been made, on the blood of patients treated with x-rays for ankylosing spondylitis, of the effect of time after exposure on the proportion of cells in blood-cultures with unstable chromosome aberrations (Cu cells), and also of the effect of time in culture on the proportion of Cu cells.It has been found that the effect of prolonging culture time is a significant decrease in the numbers of Cu cells, and of the proportion of these that are probably in their first division since the production of radiation damage (X1 cells). It has also been found that, provided cells are harvested after about 48 hours in culture, the proportion of X1 cells remains high, even though irradiation may have taken place several years previously.The implications of these findings are discussed in relation to making observations on chromosome damage after in vivo radiation exposure, and also in regard to the problem of the life-span of lymphocytes.