The solubility of NiO(cr) was measured using flow techniques and a potentiometric method from ca. 0 to 350°C in aqueous solutions as a function of pH. A more limited study of the solubility of -Ni(OH)2(cr) was conducted by both techniques to 200°C. These results indicate that the transition temperature at which nickel hydroxide dehydrates to form the oxide is ca. 75°C, much lower than previousl...

In simple rule-switching tests, 3and 4-yearolds can follow each of two sorting rules, but sometimes make perseverative errors when switching. Older children make few errors, but respond slowly when switching. These age-related changes might reflect the maturation of executive functions (e.g. inhibition). However, they might also reflect children’s ability to use task cues. Cue processing diffic...

An analysis of wastewater samples collected from different industrial regions of Egypt demonstrated dangerously high levels of nickel (0.27-31.50mgL(-1)), chromium (1.50-7.41mgL(-1)) and zinc (1.91-9.74mgL(-1)) in the effluents. Alarmingly, these heavy metals are among the most toxic knownones to humans and wildlife. Sixty-nine Actinomycete isolates derived from contaminated sites were evaluate...

concentrations of six heavy metals including cr, mn, ni, pb, v and zn were determined in topsoil (from 47 grid cells), surface water (4 streams) and groundwater (8 wells and 4 qanats) from an agriculturalarea located at south part of the iranian capital, near the tehran oil refinery. concentrations of the elementswere measured using flame and flameless atomic absorption spectrometry. based on t...

The aim of this study was to measure marginal fit at cylinder-abutment interface, before and after overcasting procedure. A hexagonal implant was fixed to a stainless steel base and a Estheticone-like abutment used during all the experiment. Before casting procedure, gold (Group I) and Ni-Cr-Be (Group II) premachined cylinders were tightened to the abutment with gold and titanium screws (in bot...

Duckweeds are of special interest, as they are naturally growing weeds that have the capacity to tolerate and remove toxic pollutants, including heavy metals from the environment. Studies have revealed that duckweed (Lemna minor) can tolerate and remove heavy metals from aqueous solutions. In the present study, the efficiency of L. minor in the removal of Ni and Cr individually from aqueous sol...

The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissoluti...

DNA-protein cross-links (DPXs) in fish erythrocytes represent a potential biomarker for exposure to metal cations, such as hexavalent chromium (Cr[VI]) and divalent nickel (Ni[II]). Species-specific sensitivities to DPX formation were studied by coexposure of juvenile specimens of rainbow trout, hybrid bluegill, and channel catfish to waterborne metals, such as Cr(VI) and Ni(II). In a species c...

The objective of this study was to improve the oxidation resistance of electroplated Ni-Cr coatings by introducing a fine dispersion of yttria (Y2O3) nanoparticles to the coatings. A technique was developed to produce Y2O3 nanoparticles nm in size. Electroplating conditions were also investigated and it was found that pulse plating could produce high quality coatings without cracking. The Y2O3 ...