The genus
Rutilus
is a widely distributed lineage of cyprinids and ranges from West Europe to East Siberia. Although matrilineal phylogeny and phylogeography of western species were already studied, ...roaches from remaining part of the range were not examined. Phylogenetic analysis based on cytochrome
b
sequences detected the following three major phylogenetic clades: (i)
R. frisii
, (ii)
R. rutilus
s. str., and (iii) group of six Ponto–Caspian taxa:
R. caspicus
,
R. heckelii
,
R. rutilus aralensis
,
R. rutilus lacustris
,
R. schelkovnikovi
, and
R. stoumboudae
. Our results suggest that these “species” within Ponto–Caspian clade could be a single species (
R. lacustris
by priority of description). The Ponto–Caspian clade is most widely distributed among others and covers the freshwaters from the Aegean Sea basin to Laptev Sea tributaries. Both
R. rutilus
s. str. and Ponto–Caspian clades sympatrically occur in Black Sea and Caspian Sea basins, Azov Sea itself, and even in drainage of White Sea. The vastest zone of contact (approximately 1700 km) was detected in the Volga basin. The spatial pattern of haplotype diversity and the shape of haplotype network argued for multiple refugia in Ponto–Caspian region as well as a rapid post-glacial colonization of Volga River and Siberia.
The work is devoted to the creation of a hard-alloy tool for finishing processing of heat-resistant and titanium alloys. Objective: to increase the efficiency of carbide blade tools for finishing ...machining of aircraft parts of heat-resistant and titanium alloys by means of ultrafast grinding, to determine the method of hardening the cutting part and the conditions of its operation. Subject of the research: the quality of the cutting wedge (conditional inscribed radius of the blade rounding, the presence of microchips, blockages and microhardness) obtained by ultrafast grinding and work-hardening of the cutting part and the determination of the conditions of its operation. Objectives: to implement the method of carbide tools ultrafast sharpening, providing the required quality of the cutting wedge, characterized by the conditional inscribed radius of rounding of the blade, the presence of microchips, blockages and microhardness, capable of producing blade processing of parts from heat-resistant and titanium alloys with an accuracy of 3...5 microns and roughness of Ra 0.2...0.4 microns; to investigate the process of superfast sharpening and to determine the effect of sharpening modes of carbide metal cutting tools on the quality of the sharpened tools cutting wedge; to investigate the reason for the reduction of the durability of the cutting tool while reducing the rounding radius of the blade and to determine the composition of the hardening coating, which slightly reduces the sharpness of the blade; to investigate the influence of cutting modes of finishing heat-resistant and titanium alloys with a tool blade sharpness up to 5 microns on its durability, as well as the surface roughness and accuracy of the part. Research methods: electron microscopy (Jeol JCM-5700, an energy-dispersive spectrometer attachment JED-2300; NTEGRA PRIMA (NT-MDT)); optical microscopy (MikroCad Premium, ODSCAD measurement program; Axio Observer.A1m); vibrodynamic analyzer (DIANA-2M); coating thickness measurement method (Calotest CAT-S-0000); microhardness measurement method (PMT-3 and DM 8 B AFFRI); determination of the characteristics of the tribotechnical properties by the method of testing for friction and wear (II5018); determination of cooling capacity (Compaton). Theoretical and calculation methods: simulation method; end element method; methods of mathematical statistics.
The effect of isomorphic substitution of atoms on crystal structure and properties of oxide compounds is one of the main tasks of modern materials science. This work is devoted to the study of Ba ...atoms by smaller Sr atoms’ substitution in two-slab perovskite-like structure of BaNd
2
In
2
O
7
and its effect on the structural features and electroconductive properties of the Ba
1−
x
Sr
x
Nd
2
In
2
O
7
indates synthesized. A characterization, including data of X-ray diffraction, structural calculations (Rietveld method) of phases obtained, is presented. Existence region of Ba
1−
x
Sr
x
Nd
2
In
2
O
7
solid solutions with a two-slab perovskite-like structure (0 ≤
x
≤ 0.2) was established and their coordinate parameters (
x
= 0.1 and
x
= 0.2) are refined. Ba
1−
x
Sr
x
Nd
2
In
2
O
7
structure is based on two-dimensional (infinite in the
XY
plane) perovskite-like blocks of two slabs connected by vertices of deformed InO
6
octahedra. Neighbouring blocks are separated by a slab of NdO
9
polyhedra and interconnected by O–Nd–O bonds. Correlations between substitution degree of barium atoms and electroconductive properties have been established. It is shown that such type of substitution leads to a decrease in the Nd–O2 interblock bond length (from 0.223(2) nm at
x
= 0 to 0.214(1) nm at
x
= 0.2). This brings the constitution of two-dimensional structure of Ba
1−
x
Sr
x
Nd
2
In
2
O
7
closer to the structure of three-dimensional perovskite and leads to its destruction at
x
> 0.2. Increase in the degree of substitution is also accompanied by a gradual decrease in specific conductivity of ceramic grains and increase in the activation energy and their own electrical conductivity.
MicroRNAs in the Myelodysplastic Syndrome Veryaskina, Yuliya A.; Titov, Sergei E.; Kovynev, Igor B. ...
Actanaturae,
04/2021, Letnik:
13, Številka:
2
Journal Article
Odprti dostop
The myelodysplastic syndrome (MDS) holds a special place among blood cancers, as it represents a whole spectrum of hematological disorders with impaired differentiation of hematopoietic precursors, ...bone marrow dysplasia, genetic instability and is noted for an increased risk of acute myeloid leukemia. Both genetic and epigenetic factors, including microRNAs (miRNAs), are involved in MDS development. MicroRNAs are short non-coding RNAs that are important regulators of normal hematopoiesis, and abnormal changes in their expression levels can contribute to hematological tumor development. To assess the prognosis of the disease, an international assessment system taking into account a karyotype, the number of blast cells, and the degree of deficiency of different blood cell types is used. However, the overall survival and effectiveness of the therapy offered are not always consistent with predictions. The search for new biomarkers, followed by their integration into the existing prognostic system, will allow for personalized treatment to be performed with more precision. Additionally, this paper explains how miRNA expression levels correlate with the prognosis of overall survival and response to the therapy offered.
The aim of the study, results of which are presented in this paper, is to analyse methods and tools for constructing an ontology related to solving compute-intensive problems and to form algorithms ...of its use. This problem arises from the need to solve problems using modern and future supercomputers, containing millions and, in the long term, billions of simultaneously operating computing cores and having a huge degree of parallelism. In solving such problems, the researcher should be well versed in both computational methods for solving the problem and modern supercomputer technologies, which is not always the case. One of the solutions to this problem is the creation of a knowledge base that includes ontological descriptions of methods for solving compute-intensive problems and architectures of supercomputers that can be used to solve them. The development of ontologies for a given subject area is one of the most important stage in creating an intelligent support system for solving specific compute-intensive problems. The paper discusses the methods and tools that are used to build the ontology. The paper also presents examples of the development of ontologies for astrophysics and geophysics problems.
A research technique was developed. The selection of the processed samples (sizes, material, operating conditions) was carried out. The physical and computational model of the process of cold plastic ...deformation of samples from tool heat-resistant steel X12M was developed. The technique for studying the effect of cold plastic deformation on the adhesive ability of a substrate - coating system is presented.
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