Polypyrrole (PPy) conducting polymer prepared by chemical oxidation method using FeCl3.6H2O as an oxidant has exhibited 100% adsorption efficiency for the removal of nickel ions from aqueous solution. At pH 7, 100% nickel absorption was found by the prepared polypyrrole as measured by atomic absorption spectrophotometry. At both acidic and alkaline solutions, the adsorption efficiency of PPy wa...

Research on nickel carcinogenesis from 1975 to March 1980 is reviewed. Epidemiological studies have strengthened the evidence that workers in nickel refineries have increased risks of cancers of the nasal cavities and lungs. Clinical investigations have resulted in improved diagnosis, classification, and management of cancers of respiratory organs in nickel refinery workers. Carcinogenicity tes...

Background The ubiquity of nickel in the environment and its common presence in food and water mean that humans are constantly exposed to nickel. Although nickel is not acutely toxic at low levels, it is a carcinogen and has been linked to cellular oxidative stress [1]. Soils that develop on serpentinite, a metamorphic rock type derived from ultramafic igneous rocks (and the state rock of Calif...

Nickel homeostasis is important for pathogenic and ureolytic bacteria, which use this metal ion as enzymatic cofactor. For example, in the human pathogen Helicobacter pylori an optimal balance between nickel uptake and incorporation in metallo-enzymes is fundamental for colonization of the host. Nickel is also used as cofactor to modulate DNA binding of the NikR regulator, which controls transc...

X-ray absorption spectra were measured for a number of nickel oxycompounds and fluorides which contain nickel with valencies in the range of 2 to 4. Information on the local structure and nature of bonding of nickel were derived using theoretical standards genmted with the FEFF code. The energies of the main Ni K-edge and the pre-edge peak were found to shift to higher values by about 1.5 and 0...

Nickel is still the most frequent cause of contact allergy, despite the EU regulation limiting nickel release from consumer items intended for prolonged contact with the skin, such as jewellery, buttons, and watches. It is obvious that the current restriction is insufficient (1). It has been shown that nickel is deposited onto the skin by short and repetitive contact in amounts sufficient to ca...

The effects of increasing nickel from 3 to 7 and 9 wt. % were investigated in high strength steel weld metals with 2 wt. % manganese. It was found that nickel additions were positive for strength but negative for impact toughness. Significant segregation of nickel and manganese to interdendritic regions was observed with the two higher nickel contents. In these weld metals a mainly martensitic ...

The effects of increasing the nickel content from 3 to 7 or 9 wt-% were investigated in high strength steel weld metals with 2 wt-% manganese. Nickel additions were beneficial to strength but detrimental to impact toughness. Significant segregation of nickel and manganese to interdendritic regions was observed at the two higher nickel contents. In these weld metals a mainly martensitic microstr...

Nickel (Ni) is a naturally occurring metal existing in various mineral forms and it is present in all compartments of the environment and ubiquitous in the biosphere as nickel compounds and complexes. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to 3d group transition metals and is hard and ductile. Nickel is one of the five ferromagnetic elements. It is also ...

Among numerous active electrode materials, nickel hydroxide is a promising electrode in electrochemical capacitors. Nickel hydroxide research has thus far focused on the crystalline rather than the amorphous phase, despite the impressive electrochemical properties of the latter, which includes an improved electrochemical efficiency due to disorder. Here we demonstrate high-performance electroch...