The paper presents the results of the ecological study, with the analysis of landscapes and mapping of the area of the testing ground. The testing ground is located in the Eastern Transbaikalia, ...covering the part of the central part of Primorskii Range and sourth-eastern macroslope of this mountain range (having an easterly aspect for the Primorskii Range). For the analysis of the structure of geosystems and the estimation of disturbance, the basic geosystem approach is applied to modern geoinformation-cartographic and remote methods. Based on V.B. Sochava's theory of geosystems it is assumed for use in processing and ordering a large volume of information. In the paper we analyzed the regional background and main factors of the landscape differentiation of the study areas. The pyrogenic impact, which increased by the 21st century and caused the transformation of the natural structure of the Baikal mountains, caused the need to improve the methods of mapping the geosystems of topological level, their dynamics, landscape-forming processes and individual local phenomena. We identified negative digressions of geosystems for the period 1989-2019 at the experimental site, when 42% of 100 km2 of natural systems of highlands, mountain-taiga middle mountains and lowmountain-slope forests were lost.
Exosomes are nanovesicles 40-120 nm in diameter secreted by almost all cell types and providing humoral intercellular interactions. Given the natural origin and high biocompatibility, the potential ...for loading various anticancer molecules and therapeutic nucleic acids inside, and the surface modification possibility for targeted delivery, exosomes are considered to be a promising means of delivery to cell cultures and experimental animal organisms. Milk is a unique natural source of exosomes available in semi-preparative and preparative quantities. Milk exosomes are highly resistant to the harsh conditions of the gastrointestinal tract. In vitro studies have demonstrated that milk exosomes have an affinity to epithelial cells, are digested by cells by endocytosis mechanism, and can be used for oral delivery. With milk exosome membranes containing hydrophilic and hydrophobic components, exosomes can be loaded with hydrophilic and lipophilic drugs. This review covers a number of scalable protocols for isolating and purifying exosomes from human, cow, and horse milk. Additionally, it considers passive and active methods for drug loading into exosomes, as well as methods for modifying and functionalizing the surface of milk exosomes with specific molecules for more efficient and specific delivery to target cells. In addition, the review considers various approaches to visualize exosomes and determine cellular localization and bio-distribution of loaded drug molecules in tissues. In conclusion, we outline new challenges for studying milk exosomes, a new generation of targeted delivery agents.
Monte-Carlo simulation was used to study the background conditions which affect the performance of the trigger system of the BM@N experiment. A GEANT4 + QGSM software package was used for the ...simulation. The influence of the background from δ-electrons was estimated and measures to minimize this background were evaluated. Addition of lead shielding and a small change in the geometry of the target zone allow to reduce the background. The efficiency of the modified trigger system was calculated for Au+Au collisions as a function of the impact parameter. The efficiency is 100% for central and semi-central collisions.
The paper presents the results of the ecological study, with the analysis of landscapes and mapping of the area of the testing ground (80 km2). The testing ground is located in the Eastern ...Transbaikalia, covering the part of the Urbican basin and its mountainous frame. For the analysis of the structure of geosystems and the estimation of disturbance, the basic geosystem approach is applied to modern geoinformation-cartographic and remote methods. Based on V. B. Sochava theory of geosystems it is assumed for use in processing and ordering a large volume of information. In the paper we analyzed the regional background and main factors of the landscape differentiation of the study areas. It is established that the main factors influencing the landscape diversity are the aspect and steepness of the slopes, the composition and structure of rocks, the absolute height, the amount of atmospheric precipitation, and anthropogenic impacts. It is determined that the influence of the lithomorphic factor is widespread throughout the study areas, the hydromorphic factor is also important, the cryomorphic factor occurs additionally in the alpine and goletz zones. There are structural-dynamic characteristics of landscapes of a topological level. Structural features of topological geosystems are revealed, and large-scale maps of key areas are compiled. Map of the landscape-typological structure was created on the basis of the structural-dynamic and facies analysis of landscapes.
A morphometric analysis is made of the relief for the mountainous territory in Western Cisbaikalia: the Primorskii Range, the landscapes of which have been transformed for a long time under the ...influence of the pyrogenic factor. Under such conditions, it becomes relevant to determine the relationships between the geomorphological conditions of the territory and the distribution of postpyrogenic landscapes, as well as the possibility of using the results in landscape mapping. The basis for maps of surface curvature is provided by a digital elevation model based on ALOS radiometer data with a resolution of 30 m. Using geoinformation analysis, maps of the steepness and exposure of slopes and horizontal and vertical curvature are obtained and the statistical coefficients of these indicators for the study area are determined. To determine the degree of influence of geomorphological conditions on the distribution of postpyrogenic landscapes, a geomorphological map is compiled, a typification of the relief is carried out according to the altitudinal layers, and a correlation with corresponding types of locations is determined. At this stage of research, the following connections are revealed between the geomorphological heterogeneity of the local relief and the nature of the spread of fire: in some cases, river valleys become barriers to the spread of fire (their summits are usually not affected by fire). Another option for barriers are the ridges located across slopes; thus, the orientation of orographic relief elements can be designated as a limiting factor in the spread of fires. The prevailing southeastward exposure of the macroslope of the Primorskii Range, which coincided with the northwestward direction of the main air transport, becomes an intensifying factor in the spread.
We proposed a procedure for the rapid sample preparation of food samples for the determination of nitrofuran metabolites in them by HPLC–MS/MS, using 5-nitro-2-furaldehyde as a new derivatizing ...agent. Meat samples from broiler chickens treated with nitrofurans for 10 days were used to demonstrate that the time of hydrolysis–derivatization in a thermostated ultrasonic bath could be significantly shortened by raising temperature to 80°C and increasing the concentration of hydrochloric acid to 0.5 M. Metabolites of Furaltadone, Furazolidone, Nitrofurantoin, and Nitrofurazone in chicken meat, liver, stomach, and heart are determined using the developed procedure and an official method. The proposed method ensures the quantitative isolation of metabolites.
In this study the dV/dt values for 4H-SiC commercial diodes have been determined experimentally. The experimental measuring tester for determination of dV/dt values of diodes at amplitude of impulse ...of reverse voltage VA (VA=100÷950 V) applied across the Schottky diode was constructed. It was determined that the dV/dt value almost linearly increase with increase of impulse of reverse voltage VA (in interval of VA=100÷900 V) applied across the 5DS402A9 diode for the first time. It is determined experimentally that at the maximal impulse of reverse voltage (900 V) applied across the silicon carbide commercial 5DS402A9 diode produced by domestic company the dV/dt value (148 V/ns) is comparable with others commercial diodes and therefore diode of this type can stably function in electric power circuit.
We review the results of theoretical and experimental studies of high-power free-electron masers (FEMs), which are performed jointly by the Joint Institute for Nuclear Research (JINR) and the ...Institute of Applied Physics of the Russian Academy of Sciences (IAPRAS), using the LIU-3000 linear induction accelerator that has a particle energy of about 0.8 MeV, a beam current of up to 200 A, and a pulse duration of 200–250 ns. Various types of Bragg resonators are compared, including two-mirror schemes and resonator cavities with a jump in the corrugation phase. The nonlinear dynamics of FEMs with the cavities of the above-specified types is studied, and the regions of realization of single-mode, single-frequency regimes, when generators are excited by relativistic electron beams moving in a helical undulator and focused by a uniform longitudinal magnetic field, are found.
The results of the theoretical analysis are confirmed by experimental studies. When a Bragg cavity with a corrugation phase jump is used in the regime of the reverse guiding field in the 8-mm wavelength range, a FEM with an output power of about 20–30 MW and a radiation spectrum width of 6–7 MHz is realized, which is close to the theoretical limit. The record-breaking set of parameters obtained for this class of generators (efficiency, power, stability of the single-mode generation regime in a sequence of up to 10
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pulses) made it possible to use FEM radiation in several applications, including the study of the resource of high-gradient accelerating structures under pulsed periodic thermal loads. To expand the spectrum of potential applications that require control over the frequency and phase of the radiation, the possibility to create wideband amplifying circuits of FEMs is demonstrated.
In order to bring FEMs over to the short-wave part of the millimeter-wavelength range, it is proposed to use modified Bragg structures based on the coupling of traveling and quasi-critical waves. It is shown that including quasi-critical waves in the feedback circuit allows one to improve significantly the selectivity of Bragg cavities (as compared with their “conventional” analogs based on the coupling of counterpropagating wave beams with high group velocities) for the transverse dimensions that reach up to 10–20 wavelengths. Operability of novel cavities has been confirmed experimentally in prototypes of FEM oscillators operating in the K
a
- to W-bands at a multimegawatt power level and having a transverse dimension of up to 5 wavelengths. Prospects for advancing the studied class of generators to the subterahertz/terahertz frequency range on the basis of new-generation linear induction accelerators, which have been developed at the Budker Institute of Nuclear Physics (BINP), Siberian Branch of the Russian Academy of Sciences and form electron beams with a particle energy of 5–20 MeV and kiloampere currents, are discussed.
Breakdown voltage for Ti/4H-SiC type Schottky diode with six guard rings have been calculated theoretically and by mean of numerical simulations. It is shown that the breakdown voltage can be ...increase at the minimum on 100 V in case when thickness of the n-type 4H-SiC epitaxial layer increase from 18 up to 22 μm. It is established that the breakdown voltage value for Ti/4H-SiC type Schottky diode with guard rings calculated by mean simulation in ATLAS program and theoretically have good approximation. Thus, above approach gives the possibility for projection of diode structure with different 4H-SiC epitaxial layer thickness with higher breakdown voltage value.
The test element for quality control of SiC Schottky type high voltage diodes has been constructed at first in this study. It is shown that proposed test element give possibility for determination of ...important parameters for testing diode before Schottky contact formation and therefore can be decrease production costs in production of SiC Schottky type high voltage diodes.
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