Vol 489, No 2 (2019)

A combined scheme of the discontinuous Galerkin method is proposed. This scheme monotonously localizes the fronts of shock waves and simultaneously maintains increased accuracy in the regions of smoothness of the calculated solutions. In this scheme, a non-monotonic version of the third-order DG method is used as the baseline and a monotonic version of this method is used as the internal one, in which a nonlinear correction of numerical flows is used. Tests demonstrating the advantages of the new scheme compared to the standard monotonized variants of the DG method are provided.

The problem of constructing a numerically realizable model of a three-dimensional homogeneous random field in a “horizontal” layer 0 < z < H with given one-dimensional distribution and correlation function of the integral over “vertical” coordinate z is solved. An aggregate of n independent elementary horizontal layers of thickness h = H/n, vertically shifted by a random value uniformly distributed in the interval (0, h) is considered as a basic model.

A waveguide occupies a domain G with several cylindrical ends. The waveguide is described by a nonstationary equation of the form i∂_t f = Af , where A is a selfadjoint second order elliptic operator with variable coefficients (in particular, for A = -Δ, where Δ stands for the Laplace operator, the equation coincides with the Schrodinger equation). For the corresponding stationary problem with spectral parameter, we define continuous spectrum eigenfunctions and a scattering matrix. The limiting absorption principle provides expansion in the continuous spectrum eigenfunctions. We also calculate wave operators and prove their completeness. Then we define a scattering operator and describe its connections with the scattering matrix.

A team of authors developed a technology for producing biocompatible biodegradable polymer films based on high-molecular polylactide with the properties necessary for medical and agricultural use. A technology has been developed for the inclusion of active substances (gentamicin sulfate, lincomycin hydrochloride, cefotaxime) into films of high-molecular polylactide. The rate of release of active substances from polylactide can vary with time as a decaying exponent, as well as a function close to linear. The process of release of active substances is significantly affected by the pH of the surrounding film of the solution. It was found that the dynamics of release of active substances from biocompatible biodegradable polymer films created on the basis of high-molecular polylactide depends on the properties of the substance immobilized in the film, the technology of the film and the conditions under which the extraction is carried out. The technical parameters of biocompatible biodegradable polymer films based on high-molecular polylactide are quite suitable for the manufacture of coatings of stents and prostheses with prolonged and controlled release of drugs into the surrounding tissues, as well as for use in agriculture to increase the safety of the harvest.

The novel biodegradable biocomposites on the base of poly(3-hydroxybutyrare) nanofibers with embedded iron oxide nanoparticles have been studied by transmission electron microscopy (TEM), Mössbayer spectroscopy, small angle X‑ray scattering (SAXS), and macroscopic magnetization techniques.

Zircons from volcanic and plutonic rocks of Nembonda volcanic field (the part of Anadyr segment of the Okhotsk-Chukotka volcanic belt) yield the following SHRIMP U-Pb ages, Ma: 147,7±2; 123,8±1,7; 119,3±1,7; 9,8±0,5; 80,55±0,96. These results confirm the hypothesis about the significant Aptian magmatic event in Verkhoyansk-Chukotka tectonic province, and give rise to the revision of the boundaries of the Okhotsk-Chukotka belt.

This study presents the first results of oxygen isotope analyses (δ¹⁸O) collected on zircons from the Talnakh economic intrusion within the Noril’sk province. Zircons from gabbro-diorite, gabbroic rocks of the layered series and plagioclase-bearing wehrlite have similar mantle-like mean δ¹⁸O values (5,39 ± 0,49‰; 5,64 ± 0,48‰ and of 5,28 ± 0,34‰, respectively), which differ from δ¹⁸O in zircons from sulfide-bearing melanocratic troctolite with a taxitic texture in the lower part of the intrusion (mean δ¹⁸O = 6,50 ± 0,98‰). These new oxygen isotope data support (i) the mantle-derived origin of the primary magma(s), parental to the Talnakh intrusion, and (ii) possible involvement of a crustal component during the formation of sulfide-bearing taxitic-textured rocks.

The results of the spectral analysis of coordinate data obtained as a result of the permanent registration in the Geophysical Observatory “Mikhnevo” IDG RAS using a stationary GPS receiver. A detailed analysis of digital data series for a long period of time (observations are carried out from June 2014 to the present time) showed that the spectrum of variations of coordinate data is characterized by the presence of a significant number of quasi-harmonic components, among which there are fluctuations with periods close to the periods of tidal waves.

The paper analyzes the results of integrated studies, obtained in the recent years, of bottom sediments and coastal transects in the Sea of Azov. The changes of natural conditions, taking place in its sea basin during the last 20 thousand years, are coordinated with the chronology of the World Ocean level fluctuations. The stages of the sea level increase, caused by the glacier shields’ melting, are considered. Due to the fact, it is noted that the change of the level of the World Ocean made a decisive impact on the formation of the Sea of Azov current water area conditions.

The effect of γ-radiation on the level of nuclear DNA damage in onion seedlings (Allium-test) was studied using the comet assay. DNA breaks were first found in cells of onion seedlings exposed to low-dose radiation (≤ 0,1 Gy). Dose dependence of DNA damage parameters showed nonlinear behavior: a linear section in the low-dose region (below 0,1 Gy) and a dose-independent plateau in the dose range between 1 and 5 Gy. Thus, the comet assay can be used to estimate the biological effects of low-dose gamma-radiation on Allium cepa seedlings.

Targeted toxins are promising anticancer agents that allow selectively destroying cancer cells due to the increased content of onco-specific markers on their surface. The use of such anti-cancer toxins in medicine is mainly hampered by their high non-specific toxicity, in particular, hepatotoxicity. In our work on human cell line, we have shown that the removal of the DARPin-PE40 translocation toxin domain leads to a decrease in hepatoto-xicity. The same effect is also observed when inactivation of the furin cleavage site in the DARPin-PE40 molecule was done. Simultaneous removal of both the translocation domain and the furin cleavage site showed the best results. This toxin modification can be used to create more selective anti-cancer toxins.

Laboratory experiments were performed to compare the electrical activity and behavior in Clarias fuscus during spawning. Each of the multiple matings of the male and female was preceded by an amplexus - a mutual pose in which the male tightly covers the female’s head and remains in close contact with it until the end of mating. The spawning behavior of C. fuscus was accompanied by monopolar electrical pulses (MP) of two types: single MPs, similar to those observed in other behavioral situations (aggression, hunting) and specific MPs, observed only during spawning bursts of serial MPs (burst MPs), at intervals which are comparable with their duration. Each recorded burst MPs (71) corresponded to one mating, and each recorded single MP (63) corresponded to an attack of one fish on another. In different behavioral situations (matings and attacks), MPs differ significantly in amplitude and duration; and for MPs in bursts, in their degree of asymmetry. It can be assumed that the involvement of MPs in the spawning behavior of C. fuscus is similar to that studied earlier in Clarias macrocephalus, and is a common feature for Clariidae.