Spectroellipsometric Characterization of Multilayer Sol-Gel Fe2O3 Films

Multilayer Fe₂O₃ films were deposited by the sol-gel method on glass substrates using three successive deposition procedures. The films were thermally treated for 1 h at 300°C.The optical and microstructural properties of these films were investigated by spectroscopic ellipsometry (SE) in the 500–1000 nm range. The optical gap was found by fitting the dispersion of the film refractive index (n) with the Wemple-DiDomenico (WDD) formula.The ellipsometric measurements showed also that the Fe₂O₃ films are anisotropic. The birefringence values (n) of the sol-gel films (0.05–0.08) are smaller than the large values of the Fe₂O₃ (which are around 0.28) but increase with the crystalization of the films. AFM mesurements showed that the films treated at 300°C start to crystallize.     

Koszul–Sullivan Models and the Cohomology of Certain Solvmanifolds

In this paper we develop a technique of working with graded differential algebra models of solvmanifolds, overcoming the main difficulty arising from the non-nilpotency of the corresponding Mostow fibrations. A graded differential model for solvmanifolds of the form G/ with G=RN is presented (N is a nilpotent Lie group, G is a semi-direct product). As an application, we prove the Benson–Gordon conjecture in dimension four.     

Reactivity of acrylic monomers

Summary The copolymerization of N,N-diethylacrylamide (M_l) with methyl acrylate (M₂) was investigated and reactivity ratiosr ₁= 0.41 andr ₂ = 0.52 obtained. Also the distribution of diad fractions was calculated and the results were interpreted in terms of the product of reactivity ratios. The tendency of the two monomers to alternate was explained on the basis of differences in polatities between the double bonds, this explanation being supported both by the values ofe parameter and NMR spectroscopy data. A copolymerization mechanism was suggested.With 5 figures and 2 tables     

Mechanochemical reactions on poly (vinyl chloride)

This paper is concerned with molecular phenomena appearing during deformation of poly(vinyl chloride) under tensile stress conditions. By using indirect techniques (reactions with radical acceptors, with vinylic monomers, electron microscopy) the formation of free radicals, appearing as a consequence of splitting of chemical bonds, is evidenced. The amount of reacted radical acceptor or monomer was proved to be related to solution concentration and to the duration of mechanical stress.     

Density functional theory study of indirect nuclear spin-spin coupling constants with spin-orbit corrections

This work outlines the calculation of indirect nuclear spin-spin coupling constants with spin-orbit corrections using density functional response theory. The nonrelativistic indirect nuclear spin-spin couplings are evaluated using the linear response method, whereas the relativistic spin-orbit corrections are computed using quadratic response theory. The formalism is applied to the homologous systems H2X (X=O,S,Se,Te) and XH4 (X=C,Si,Ge,Sn,Pb) to calculate the indirect nuclear spin-spin coupling constants between the protons. The results confirm that spin-orbit corrections are important for compounds of the H2X series, for which the electronic structure allows for an efficient coupling between the nuclei mediated by the spin-orbit interaction, whereas in the case of the XH4 series the opposite situation is encountered and the spin-orbit corrections are negligible for all compounds of this series. In addition we analyze the performance of the density functional theory in the calculations of nonrelativistic indirect nuclear spin-spin coupling constants.     

Fixed points and powers of self-maps of -spaces

We give a new proof of the following result due to Duan: Let be any self-map of a finite connected -space. Then has a fixed point if . Our proof is based on an approach due to Steve Halperin, whereby the Lefschetz number of a self-map is expressed in terms of the eigenvalues of the induced homomorphism of rational homotopy groups. This allows us to give a considerably shorter proof which avoids most of the technicalities of the original proof.

     

The antioxidant response induced by Lonicera caerulaea berry extracts in animals bearing experimental solid tumors

Lonicera caerulea is a species of bush native to the Kamchatka Peninsula (Russian Far East) whose berries have been extensively studied due to their potential high antioxidant activity. The aim of our work was to investigate the in vivo effects of the antioxidant action of Lonicera caerulea berry extracts on the dynamics of experimentally-induced tumors. Our data showed that aqueous Lonicera caerulaea extracts reduced the tumor volume when administered continuously during the tumor growth and development stages, but augmented the tumor growth when the administration of extracts started three weeks before tumor grafting. Prolonged administration of Lonicera caerulaea berry extracts induced the antioxidant defense mechanism in the tumor tissues, while surprisingly amplifying the peripheral oxidative stress.     

Eugenol-Functionalized Magnetite Nanoparticles Modulate Virulence and Persistence in Pseudomonas aeruginosa Clinical Strains

Efficient antibiotics to cure Pseudomonas aeruginosa persistent infections are currently insufficient and alternative options are needed. A promising lead is to design therapeutics able to modulate key phenotypes in microbial virulence and thus control the progression of the infectious process without selecting resistant mutants. In this study, we developed a nanostructured system based on Fe₃O₄ nanoparticles (NPs) and eugenol, a natural plant-compound which has been previously shown to interfere with microbial virulence when utilized in subinhibitory concentrations. The obtained functional NPs are crystalline, with a spherical shape and 10–15 nm in size. The subinhibitory concentrations (MIC 1/2) of the eugenol embedded magnetite NPs (Fe₃O₄@EUG) modulate key virulence phenotypes, such as attachment, biofilm formation, persister selection by ciprofloxacin, and the production of soluble enzymes. To our knowledge, this is the first report on the ability of functional magnetite NPs to modulate P. aeruginosa virulence and phenotypic resistance; our data highlights the potential of these bioactive nanostructures to be used as anti-pathogenic agents.