A potentiometric DNA sensor for determining autoimmune antibodies to DNA

A new technique is proposed for detecting interactions between DNA and DNA autoimmune antibodies using a potentiometric sensor based on a glassy-carbon electrode modified with polyaniline and native DNA from chicken erythrocytes. It is shown that the DNA-antibody interaction changes the rate of polyaniline doping in transferring the DNA sensor from an alkaline (pH 7.5) solution, which is optimum for the immunochemical reaction, to an acidic (pH 3.0) solution. The dynamics of the variation of the DNA sensor potential depends on the titer of antibodies and their origin. The dependence of the DNA sensor signal on the dilution of the blood sera from systemic lupus erythematosus and autoimmune thyroiditis patients shows that DNA antibodies can be diagnosed by the characteristic maximum in the dilution curve found in the range of serum dilutions from 1: 20 to 1: 50.     

On the isomorphism problem in the class of extensions of a free group by an infinite cyclic group

In the automorphism group of a rank 3 free group we find two nonconjugate automorphisms whose mapping tori are isomorphic groups.     

Spectral properties of some problems in mechanics of strongly nonhomogeneous media

Spectral properties of the following three homogenized problems in the mechanics of strongly nonhomogeneous media are considered: the “double porosity” problem, the oscillation problem for a mixture of two viscous compressible liquids, and the oscillation of a medium consisting of an elastic frame and a viscous liquid. For all three cases results on the structure of the spectrum and on the existence of so-called “spectral gaps” are obtained.     

On <Emphasis Type="Italic">W</Emphasis>-geometry of Toda systems

We describe W-geometry of two-dimensional Toda systems associated with the Lie algebra C _n . __________ Translated from Fundamental’naya i Prikladnaya Matematika (Fundamental and Applied Mathematics), Vol. 11, No. 1, Geometry, 2005.     

4-(Isoindolin-5-yl)amino-4-oxobutyryl-β-alkoxyphenyl-β-alanines, new RGDF mimetics. Synthesis, affinity to fibrinogen receptors, antiaggregatory properties, and their correlation with the hydrophobicity

A new series of RGDF mimetics, derivatives of 4-(isoindolin-5-yl)amino-4-oxobutanoic acid, was synthesized. The compounds obtained inhibit efficiently the thrombocytes aggregation in experiments in vitro; their biological targets are fibrinogen receptors. The antiaggregatory activity and the affinity correlate with the hydrophobicity of the compounds.     

The role of readily hydrolyzable polysaccharides of larch wood in manufacture of board materials

Role of readily hydrolyzable polysaccharides of larch wood in production of board materials is studied.     

Hydrolytic degradation and thermal stability of poly(naphthylimides) based on naphthalene-1,4,5,8-tetracarboxylic dianhydride and bis(naphthalic anhydrides)

The molecular properties of a number of new poly(naphthylimides) derived from naphthalene-1,4,5,8-tetracarboxylic dianhydride and bis(naphthalic anhydrides) have been studied. On the basis of hydrodynamic studies of the polymers at various stages of their thermal degradation in 96% H₂SO₄ and thermogravimetric measurements, the hydrolytic stability and thermooxidative resistance of the polymers have been compared. A correlation between the experimental data and the chemical structure of molecular chains has been established.     

Asymptotics in the Baum—Katz formula for random fields

In 1996, D. Deng established an analog of the Baum—Katz theorem on the convergence rate in the law of large numbers for multi-indexed random variables. The series describing the convergence rate depends, in a natural way, on the parameter characterizing the excess of the normalized sums over some level. In this paper, we find the precise asymptotics of the sum of this series with respect to the above-mentioned parameter. Thus, a generalization of a recent result due to A. Gut and A. Spataru is obtained.     

Influence of the prehistory of NaNbO3-Gd1/3NbO3 ceramics and single crystals on their dielectric properties

The dielectric properties of a ceramic and a single crystal of the same composition 0.9NaNbO₃-0.1Gd_1/3NbO₃ (NNG10) with different prehistories of the material are investigated in the low-and infralow-frequency ranges. It is revealed that the dielectric aging of the material based on the NaNbO₃ antiferroelectric with a smeared phase transition differs in character from similar phenomena observed in relaxor ferroelectrics.     

Quadratic differentials in problems of the product of inner radii of nonoverlapping domains

We study applications of the theory of quadratic differentials to the solution of new extremal problems of nonoverlapping domains with free poles on rays and generalize known results to a certain class of open sets. __________ Translated from Neliniini Kolyvannya, Vol. 10, No. 4, pp. 435–442, October–December, 2007.