Magnetic nanoparticles coated with polysaccharide polymers for potential biomedical applications

This study reports a two-steps route for obtaining magnetic nanoparticles–polysaccharide hybrid materials consisting of Fe₃O₄, NiFe₂O₄ and CuFe₂O₄ nanoparticles synthesis by coprecipitation method in the presence of a soft template followed by coating of ferrite nanoparticles of 8–10-nm size range with polysaccharide type polymers—sodium alginate or chitosan. Magnetic oxide nanoparticles and the corresponding hybrid materials were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy, atomic absorption spectroscopy (AAS), FTIR spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and specific surface area measurements. The vibrating sample magnetometry confirms the superparamagnetic properties of the synthesized ferrites and hybrids. Using this route, the percent of magnetic nanoparticles retained in chitosan-based hybrid materials is nearly double in comparison with that of sodium alginate–based materials. The biological activity tests on Escherichia coli ATCC 25922, Pseudomonas aeroginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Candida scotti microorganisms show the non-toxic properties of prepared hybrid materials.     

Bioelectrochemistry for miRNA detection

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4-(Azulen-1-yl) six-membered heteroaromatics substituted in 2- and 6- positions with 2-(2-furyl)vinyl, 2-(2-thienyl)vinyl or 2-(3-thienyl)vinyl moieties

The synthesis of pyrylium and pyridinium salts and pyridines with azulene-1-yl moieties in position 4 and two 2-heteroarylvinyl groups in positions 2 and 6 was accomplished. The pyrylium salts were obtained starting from pyranones and pyridines could be prepared from these salts by treating them with ammonium acetate. The general procedures for the synthesis of pyridinium salts, which occur with good results in less delocalized electronic systems, do not take place when applied to the above obtained pyrylium salts. Therefore, as starting material 4-(azulen-1-yl)-1-(n-butyl)-2,6-dimethylpyridinium perchlorate was used, which was condensed with heteroarylcarboxaldehydes. These compounds were completely characterized and some of their spectra were discussed. Their interaction with some metal ions was revealed, observing an affinity better than in the case of simple azulenepyridines. In the last part of the paper are presented redox potentials for several pyrylium salts and pyridines in comparison with those of the nonvinylogated derivatives.     

The tent transformation can improve the convergence rate of quasi-Monte Carlo algorithms using digital nets

In this paper we investigate multivariate integration in reproducing kernel Sobolev spaces for which the second partial derivatives are square integrable. As quadrature points for our quasi-Monte Carlo algorithm we use digital (t,m,s)-nets over which are randomly digitally shifted and then folded using the tent transformation. For this QMC algorithm we show that the root mean square worst-case error converges with order for any ɛ > 0, where 2 ^m is the number of points. A similar result for lattice rules has previously been shown by Hickernell. Ligia L. Cristea is supported by the Austrian Research Fund (FWF), Project P 17022-N 12 and Project S 9609. Josef Dick is supported by the Australian Research Council under its Center of Excellence Program. Gunther Leobacher is supported by the Austrian Research Fund (FWF), Project S 8305. Friedrich Pillichshammer is supported by the Austrian Research Fund (FWF), Project P 17022-N 12, Project S 8305 and Project S 9609.     

Nanocomposites based on carbon nanotubes and redox-active polymers synthesized in a deep eutectic solvent as a new electrochemical sensing platform

Microchimica Acta - The redox polymer poly(methylene blue) was synthesized by electropolymerization in ethaline deep eutectic solvent (PMBDES), and employed in a new nanostructured composite...     

On the lightness of the mappings satisfying generalized inverse modular inequalities

We study the lightness of some mappings satisfying generalized inverse modular inequalities and we apply the results to obtain conditions of lightness, openness and discreetness of some Sobolev mappings.     

Two component lattice Boltzmann model with flux limiters

A two-dimensional finite difference lattice Boltzmann model for two-component fluid systems is introduced. Phase separaton is achieved using an appropriate expression of the bulk free energy. Flux limiter techniques are used to improve the numberical accuracy of this model.