Nonspecific acid phosphatases are a group of enzymes whose activity increases the availability of exogenous and endogenous orthophosphate either through extra- or intracellular hydrolysis of phosphate compounds. Our study demonstrates the activity of acid phosphatases in the filamentous freshwater alga Stigeoclonium tenue. These enzymes were detected following a cerium-based method in which cer...

Cerium binding activity of three different water soluble pectin compounds of different origin was studied in a batch sorption system. The Langmuir, Freundlich and BET sorption models were adopted to describe the binding reactions between metal ions and pectin molecules. The Langmuir model provided the best fit. Within the pH range from 4.0 to 6.0, the largest amount of the cerium ions was bound...

The Kondo resonance is the spectral manifestation of the Kondo properties of the impurity Anderson model, and also plays a central role in the dynamical mean-field theory (DMFT) for correlated electron lattice systems. This article presents an overview of electron spectroscopy studies of the resonance for the 4f electrons of cerium compounds, and for the 3d electrons of V2O3, including beginnin...

Highly water-soluble lanthanum and cerium citrates or malates with ethylenediaminetetraacetate (NH(4))(8)[Ln(2)(Hcit)(2)(EDTA)(2)]·9H(2)O [Ln = La, 1; Ce, 2], K(8)[La(2)(Hcit)(2)(EDTA)(2)]·16H(2)O (3) and K(6)[Ln(2)(Hmal)(2)(EDTA)(2)]·14H(2)O [Ln = La, 4; Ce, 5] (H(4)cit = citric acid, H(3)mal = malic acid, and H(4)EDTA = ethylenediaminetetracetic acid) were prepared from the reactions of lanth...

Z. Naturforsch. 55 b, 155-161 (2000); received November 10, 1999 Intermetallic Cerium Compounds, Crystal Structure New intermetallic cerium compounds Ce2 7iMg (T = Ni, Cu, Pd), CqiTjCd (T Pd, Pt, Au), and CtiTzPb (T = Pt, Au) were prepared by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. Most C e :^ ^ (X = Mg, Cd, Pb) compounds are stable after annealing at abou...

A series of montmorillonite-(Ce or Zr) phosphate crosslinked compounds has been synthesized by reaction of a cerium or zirconium cation exchanged montmorillonite (diameter ~2 pm) with phosphoric acid under appropriate conditions of concentration, addition rate and temperature. The materials thus obtained were characterized by chemical and thermal analyses, X-ray diffraction, IR spectroscopy and...

The Kondo lattice model including nearest-neighbor magnetic exchange interactions is studied here in a mean-field approximation describing both the Kondo state and the intersite magnetic correlations. In the case of antiferromagnetic correlations, our model yields a decrease of the Kondo temperature compared to the one-impurity value, giving, therefore, a ‘‘revisited’’ version of the Doniach di...

The potential toxicity and accumulation of engineered nanomaterials (ENMs) in agricultural crops has become an area of great concern and intense investigation. Interestingly, although below-ground vegetables are most likely to accumulate the highest concentrations of ENMs, little work has been done investigating the potential uptake and accumulation of ENMs for this plant group. The overall obj...

The competition between spin glass, ferromagnetism and Kondo effect is analysed here in a Kondo lattice model with an inter-site random coupling Jij between the localized magnetic moments given by a generalization of the Mattis model [15] which represents an interpolation between ferromagnetism and a highly disordered spin glass. Functional integral techniques with Grassmann fields have been us...