Ni(II) sorption onto iron oxides and in particular hydrous ferric oxide (HFO) is among the important processes impacting its distribution, mobility, and bioavailability in environment. To develop mechanistic models for Ni, extended X-ray absorption fine structure (EXAFS) analysis has been conducted on Ni(II) sorbed to HFO. Coprecipitation revealed the formation of the metastable alpha-Ni(OH)(2)...

We measured the synchrotron-radiation (SR)-based Mössbauer spectra of Ni-based nanoparticles with a hexagonal structure that were synthesised by chemical reduction. To obtain Mössbauer spectra of the nanoparticles without (61)Ni enrichment, we developed a measurement system for (61)Ni SR-based Mössbauer absorption spectroscopy without X-ray windows between the (61)Ni84V16 standard energy alloy ...

The effects of hydrogen on Ni~100! submonolayer homoepitaxy have been investigated by kinetic Monto Carlo ~KMC! simulations of the Ni growth process with and without the presence of a small hydrogen impurity. The two-dimensional KMC simulations are based upon rate constants for a set of uncorrelated Ni site-to-site hopping mobilities with and without the presence of hydrogen atoms which are fou...

Methyl-coenzyme M reductase (MCR) catalyzes the terminal step in the formation of biological methane from methyl-coenzyme M (Me-SCoM) and coenzyme B (CoBSH). The active site in MCR contains a Ni-F(430) cofactor, which can exist in different oxidation states. The catalytic mechanism of methane formation has remained elusive despite intense spectroscopic and theoretical investigations. On the bas...

The influence of composition and purity of titanium on the mechanical properties and the transformation temperatures of Ni-Ti alloy dental castings was investigated by tensile testing and differential scanning calorimetry (DSC). The compositions of the ingots were 49.0-49.2 at% of titanium content. Three grades of titanium of relatively high purity were used as starting materials. The result sh...

Se invita a los lectores a enviar cartas al Editor, con comentarios, preguntas o críticas sobre artículos que hayan sido publicados en la Revista y a las que los autores aludidos puedan responder. También serán bienvenidos los comentarios sobre problemas de actualidad biomédica, clínica, de salud pública, de ética y de educación médica. Podrá aceptarse la comunicación preliminar de datos parcia...

The structure of the title compound, [Ni(C(6)H(16)N(2))(2)]Br(2) or [Ni(Et(2)en)(2)]Br(2) (Et(2)en is asymmetric N,N-diethyl-ethylene-diamine), containing an Ni(II) atom (site symmetry ) in square-planar NiN(4) coordination, is described and contrasted with related structures containing Ni(II) in octa-hedral coordination with axial X(-) ligands (X(-) = variable anions). The dialkyl-ated N atom ...

The ability of Thlaspi goesingense Hálácsy to hyperaccumulate Ni appears to be governed by its extraordinary degree of Ni tolerance. However, the physiological basis of this tolerance mechanism is unknown. We have investigated the role of vacuolar compartmentalization and chelation in this Ni tolerance. A direct comparison of Ni contents of vacuoles from leaves of T. goesingense and from the no...

Fine-tuning of the porphyrin β-periphery is important for naturally occurring metal tetrapyrroles to exert diverse biological roles. Here we describe how this approach is also applied to design molecular catalysts, as exemplified by Ni(ii) porphyrinoids catalyzing the hydrogen evolution reaction (HER). We found that β-hydrogenation of porphyrin remarkably enhances the electrocatalytic HER react...