A solid nickel(II) complex with methionine sulfoxide

Solid Ni(C(5)H(10)NO(3)S)(2) . 2H(2)O complex was prepared and characterized. Electronic absorption spectrum shows an octahedral geometry for the complex. Infrared spectroscopy analysis shows that the metal atom is coordinated to the ligand through (COO(-)) and (S = O) groups. Thermal analysis confirmed the composition of the complex and suggests that the water molecules are not coordinated to the metal ion. The complex shows extremely high solubility in water. (C) 2000 Elsevier B.V. S.A. All rights reserved.

The use of ultrasound for cleaning the surface of stainless steel and nickel-titanium endodontic instruments

Aim the aim of this study was to evaluate the efficacy of ultrasound in cleaning the surface of stainless steel and Ni-Ti endodontic instruments.Methodology Twenty nickel-titanium instruments (10 Quantec files and 10 Nitiflex) and 20 stainless steel K-files (10 Maillefer-Dentsply and 10 Moyco Union Broach) were removed from their original packages and evaluated using a scanning electron microscope. Scores were given for the presence of residues on the surface or the instruments. The instruments were then cleaned in an ultrasonic bath containing only distilled water or detergent solution for 15 min, and re-evaluated, using scanning electron microscopy.Results Before cleaning, a greater amount of metallic debris was observed on the nickel-titanium Quantec instruments (P < 0.05), when compared to those made of stainless steel. Statistical analysis showed that the use of ultrasound was effective for cleaning the instruments, regardless of the irrigating solution or the instruments type (P < 0.05).Conclusions the use of ultrasound proved to be an efficient method for the removal of metallic particles from the surface of stainless steel and Ni-Ti endodontic instruments.

Crystal structure of bis(acetylacetonato)bis(quinoline)nickel(II), Ni(C5H14O2N)(2)(C9H7N)(2)

C28H28N2NiO4, triclinic, P (1) over bar (no. 2), a = 7.9202(6) angstrom, b = 8.0496(6) angstrom, c = 10.246(1) angstrom, alpha = 97.15(1)degrees, beta = 106.68(1)degrees, gamma = 94.686(9)degrees, V = 616.1 angstrom(3), Z = 1, R-gt(F) = 0.028, wR(ref)(F-2) = 0.078, T = 293 K.

Chemical vapor deposition of multi-walled carbon nanotubes from nickel/yttria-stabilized zirconia catalysts

Multi-walled carbon nanotubes (MWNT) were produced by chemical vapor deposition using yttria-stabilized zirconia/nickel (YSZ/Ni) catalysts. The catalysts were obtained by a liquid mixture technique that resulted in fine dispersed nanoparticles of NiO supported in the YSZ matrix. High quality MWNT having smooth walls, few defects, and low amounts of by-products such as amorphous carbon were obtained, even from catalysts with large Ni concentrations (> 50 wt.%). By adjusting the experimental parameters, such as flux of the carbon precursor (ethylene) and Ni concentration, both the MWNT morphology and the process yield could be controlled. The resulting YSZ/Ni/MWNT composites can be interesting due to their mixed ionic-electronic transport properties, which could be useful in electrochemical applications.

Crystal structure of bis(acetylacetonato)-bis(3-methylpyridine)-nickel(II) dihydrate, Ni(C6H7N)(2)(C5H7O2)(2)center dot 2H(2)O

C22H32N2NiO6, triclinic, P (1) over bar (no. 2), a = 8.335(1) angstrom, b = 9.314(1) angstrom, c = 17.045(2) angstrom, alpha = 88.45(1)degrees, beta = 82.12(1)degrees, gamma = 70.296(9)degrees, V = 1233.7 angstrom(3), Z = 2, R-gt(F) = 0.050, wR(ref)(F-2) = 0.177, T = 293 K.

Differential/combined effect of water contamination with cadmium and nickel on tissues of rats

The contamination of water by metal compounds is a worldwide environmental problem. Concentrations of metals are widely related to biochemical values which are used in disease diagnosis due to environmental toxicity. The acute combined effects of cadmium and nickel on biochemical parameters were determined and compared with those of Cd2+ or Ni2+ alone in rats. Male adult rats were given drinking solutions of CdCl2 [Cd(II) cation, 100 mg/liter] or NiSO4 [Ni(II) cation, 100 mg/liter]. For the combined treatment, the animals (Ni+Cd) received both Ni(II)) cation (100 mg/liter) and Cd(II) cation (100 mg/liter). Nickel treatment induced increased alanine transaminase (ALT) activity and hepatotoxicity, but not renal injury. In contrast, cadmium exposure produced hepatic, renal and myocardial damage, characterized by increased creatinine, total and direct bilirubin concentrations and increased ALT and lactate dehydrogenase (LDH) activities. The combined effect Ni-Cd is less toxic than cadmium alone, suggesting antagonism between these toxicants. The toxicity of nickel and cadmium, alone and in combination, decreased Cu-Zn superoxide dismutase (SOD) activity and increased lipoperoxide formation. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

An investigation of cadmium(II) and nickel(II) adsorption by chitin graft covolymer

Chitin hydrogels of poly(vinylpyrrolidone) (VP) were prepared by means of the hydrogen peroxide graft copolymerization process. The effect of the VP grafted chain on water diffusion through the biopolymer was studied. Fourier transform infrared spectra of the VP-g-Ch showed an increase in the intensities of the hydroxyl and carbonyl stretching bands indicating a reduction in the hydrogen bonding of chitin. An investigation was undertaken regarding the adsorption of nickel(II) and cadmium(II) ions from aqueous solutions by the VP grafted chitin and the effects of the grafting degree on the Cd2+ and Ni2+ sorption were studied. The Cd2+ and Ni2+ adsorption equilibrium data correlate well with the Freundlich equation. The results indicate that the Ch-g-VP graft copolymer under investigation is a potentially powerful chelating material that can be employed for Ni2+ and Cd2+ ion removal from wastewater effluents. (C) 2004 Wiley Periodicals, Inc.

Determination of nickel in fuel ethanol using a carbon paste modified electrode containing dimethylglyoxime

A mercury-free electrode chemically modified with carbon paste containing dimethylglyoxime was used for determination of nickel in fuel ethanol. The instrumental parameters and composition of the modified paste were optimized. The analytical curve for nickel determination from 5.0 x 10(-9) to 5.0 x10(-7) mol(-1) was obtained using 25 min of accumulation time. The detection limit and amperometric sensitivity obtained for this method were 2.7 x 10 mol(-1) and 5.2 x 10(8) mu A mol(-1) L, respectively. The values for nickel concentration in four commercial samples of fuel ethanol were obtained in the range of 1.1 x 10(-8) to 6.9 x 10(-8) mol(-1). A comparison to graphite furnace atomic absorption spectrometry (GFAAS) was performed for nickel determination in commercial samples of ethanol.

Oxidation of nickel(II) cyclam and tetraglycine complexes by dissolved oxygen in the presence of sulfur(IV). Synergistic effects of manganese(III) and cobalt(III)

The autoxidation of [Ni-II(cyclam)](2+) (cyclam = 1,4,8,11-tetraazacyclotetradecane) and Ni(II)tetraglycine, accelerated by S-IV is studied spectrophotometrically by following the formation of Ni-III complexes.