N. N. Shchegoleva

The effect of the composition and annealing temperature on the structure and magnetic properties of soft magnetic nanocrystalline Fe-Cu-Nb-Mo-Si-B alloys has been studied. An increase in the iron...

The interaction between homo-oligonucleotides and unmodified superparamagnetic cobalt ferrite nanoparticles has been investigated. It has been shown that the binding efficiency depends both on the nucleotide sequence and the chemical composition of the medium. According to the data obtained on the binding suppression of all oligonucleotides, apart from oligo(dG), with the surface in the presence of phosphate anions, an approach to magnetic nanoparticle-oligonucleotide nanoconjugate formation using dG₁₈T₂₅ has been implemented. In the obtained nanoconjugate, nanoparticle binding is realized due to the dG-region, whereas the thymine-containing region remains vacant. According to TEM data, the average nanoconjugate diameter is 6.3 nm; it possesses superparamagnetic properties, and its saturation magnetization is 15 emu g⁻¹. The nanoconjugate has been investigated by FTIR-spectroscopy and XRD-analysis. The hydrodynamic diameter and zeta potential of the nanoconjugate in suspension have been determined. Using fluorescently labelled oligonucleotides, it has been shown that the present nanoconjugate is able to hybridize with oligonucleotides containing a dA sequence at the 3′-end and a variable region at the 5′-end. The conjugate can be isolated from the solution and used for hybridization with the oligonucleotide complementary to the sequences at the 5′-end.

This paper presents the results of investigations of the structural state and magnetic properties of nanocrystalline cupric oxide samples with average particle sizes of approximately 40 and 13 nm,...

Sedimentation dynamics of magnetite (γ-Fe₃O₄) nanopowder (10–20 nm) in water in a gradient magnetic field B_max = 0.3 T, (dB/dz)_max = 0.13 T/cm was studied for different water flow speeds and starting particle concentrations (0.1 and 1.0 g/l). The aggregates formation in water was monitored under the same conditions. In cyclical water flow, the velocity of particle sedimentation increases significantly in comparison to its rate in still water, which corresponds to the intensified aggregate formation. However, at a water flow speed more than 0.1 cm/s sedimentation velocity slows down, which might be connected to aggregate destruction in a faster water flow. Correlation between sedimentation time and the nanoparticle concentration in water does not follow the trend expected for spherical superparamagnetic particles. In our case sedimentation time is shorter for c = 0.1 g/l in comparison with that for c = 1 g/l. We submit that such a feature is caused by particle self-organization in water into complex structures of fractal type. This effect is unexplained in the framework of existing theoretical models of colloids systems, so far. Provisional recommendations are suggested for the design of a magnetic separator on the permanent magnets base. The main device parameters are magnetic field intensity B ≥ 0.1 T, magnetic field gradient (dB/dz)_max ≈ (0.1–0.2) T/cm, and water flow speed V < 0.15 cm/s. For particle concentration c = 1 g/l, purification of water from magnetite down to ecological and hygienic standards is reached in 80 min, for c = 0.1 g/l the time is reduced down to 50 min.

The influence of several physico-technological factors on the microstructure and the magnetic and magnetoresistive properties of film structures based on Fe20Ni80/Fe50Mn50bilayers with exchange...

Morphological examination of microcirculatory bed vessels in the gastric and duodenal mucous membranes was performed in asthmatic patients. The gastroduodenal area showed signs of capillary dysfunction and a vascular component of mucosal remodeling, like bronchial wall remodeling in asthma.

The immunomorphological characteristics of the gastric mucosa were evaluated and analyzed in patients with asthma of varying severity who received or did not receive inhaled or oral glucocorticosteroid therapy and in the control group. Immunohistological examination and morphometric analysis were used to study inflammatory infiltration in fundic mucosal biopsy specimens from patients with and without asthma. There were crucial immunomorphological differences between the examined patient groups and signs of the gastroprotective effect of inhaled glucocorticosteroids used in the basic therapy of asthma on the gastric mucosa. There was evidence that it is urgent to prevent erosive and atrophic gastritis and other inflammatory stomach diseases in asthma.

The structural state of carbon in nanocomposites that are based on metals (Fe, Ni, Co, and Ag) encapsulated in carbon and produced by the gas-phase synthesis has been investigated using Raman...