Structurization of ferrofluids in the absence of an external magnetic field

Structural transformations in a model ferrofluid in the absence of an external magnetic field have been theoretically studied. The results agree with well-known laboratory experiments and computer simulations in showing that, if the concentration of particles and their magnetic interaction energy are below certain critical values, most particles form separate linear chains. If these parameters exceed the critical values, most particles concentrate so as to form branched network structures. The passage from chains to network has a continuous character rather than represents a discontinuous first-order phase transition. © Pleiades Publishing, Inc., 2013

Shear thickening of dense suspensions due to energy dissipation in lubrication layers between particles

This paper deals with a theoretical study of the shear thickening effects in concentrated suspensions of non-Brownian particles. Our analysis shows that an increase of the shear rate of the suspension flow leads to a decrease of the mean thickness of the gaps between the nearest particles in dense suspensions. In turn, this leads to the growth of energy dissipation in these gaps, which means an increase of the suspension effective viscosity with the shear rate. © 2013 American Physical Society

Association between 28 single nucleotide polymorphisms and type 2 diabetes mellitus in the Kazakh population: a case-control study.

We evaluated the associations between single nucleotide polymorphisms and different clinical parameters related to type 2 diabetes mellitus (T2DM), obesity risk, and metabolic syndrome (MS) in a Kazakh cohort. A total of 1336 subjects, including 408 T2DM patients and 928 control subjects, were recruited from an outpatient clinic and genotyped for 32 polymorphisms previously associated with T2DM and obesity-related phenotypes in other ethnic groups. For association studies, the chi-squared test or Fisher's exact test for binomial variables were used. Logistic regression was conducted to explore associations between the studied SNPs and the risk of developing T2DM, obesity, and MS, after adjustments for age and sex. After excluding four SNPs due to Hardy-Weinberg disequilibrium, significant associations in age-matched cohorts were found betweenT2DM and the following SNPs: rs9939609 (FTO), rs13266634 (SLC30A8), rs7961581 (TSPAN8/LGR5), and rs1799883 (FABP2). In addition, examination of general unmatched T2DM and control cohorts revealed significant associations between T2DM and SNPsrs1799883 (FABP2) and rs9939609 (FTO). Furthermore, polymorphisms in the FTO gene were associated with increased obesity risk, whereas polymorphisms in the FTO and FABP2 genes were also associated with the risk of developing MS in general unmatched cohorts. We confirmed associations between polymorphisms within the SLC30A8, TSPAN8/LGR5, FABP2, and FTO genes and susceptibility to T2DM in a Kazakh cohort, and revealed significant associations with anthropometric and metabolic traits. In particular, FTO and FABP2 gene polymorphisms were significantly associated with susceptibility to MS and obesity in this cohort

Kinetics of internal structures growth in magnetic suspensions

The kinetics of aggregation of non Brownian magnetizable particles in the presence of a magnetic field is studied both theoretically and by means of computer simulations. A theoretical approach is based on a system of Smoluchowski equations for the distribution function of the number of particles in linear chain-like aggregates. Results obtained in the two dimensional (2D) and three dimensional (3D) models are analyzed in relation with the size of the cell, containing the particles, and the particle volume fraction φ. The theoretical model reproduces the change of the aggregation kinetics with the size of the cell and with the particle volume fraction as long as the lateral aggregation of chains is negligible. The simulations show that lateral aggregation takes place when, roughly, φ2D>5% and φ3D>1.5%. Dependence of the average size of the chains with time can be described by a power law; the corresponding exponent decreases with the particle volume fraction in relation with the lateral aggregation. In the 3D simulations, dense labyrinthine-like structures, aligned along the applied field, are observed when the particle concentration is high enough (φ3D>5%). © 2012 Elsevier B.V. All rights reserved

Polymorphisms in genes involved in the absorption, distribution, metabolism, and excretion of drugs in the Kazakhs of Kazakhstan

A list of SNPs that were not found in heterozygous or homozygous variants. (DOC 83 kb

Heat exchange within the surrounding biological tissue during magnetic hyperthermia

The paper deals with mathematical modeling and theoretical study of the heat distribution within the surrounding biological tissue during the effect of the magnetic hyperthermia. The mathematical model is formulated and solved numerically by using the finite difference method. The intensity of heat production is used in the present model. The obtained results allow predicting the temperature change in tumor as well as in the surrounding tissue depending on intensity of the tumor heating. © 2020 International Information and Engineering Technology Association.Russian Foundation for Fundamental Investigations, RFFI: 18-08-00178, 19-52-45001Ministry of Science and Higher Education of the Russian FederationThis paper has been supported by RFFI, grants 18-08-00178, 19-52-45001 and the state program of the Ministry of Science and Higher Education of the Russian Federation (theme “Magnet” and Contract No. 02.A03.21.006)

Maximum likelihood estimates of some probability model of discrete distributions

In this work the new multivariate discrete probability model of distribution of random sums with unobserved components is proposed.The maximum likelihood estimates for this model are determined in the case that all the elements of the sample implementation, namely the observed sums of unobserved components have only singular partition. In the case, that some element of the sample implementation has more then one partition, it is not possible to establish the maximum likelihood estimates

Internal Migration of Youth in Megacities as a Factor Influencing the Migration of Youth Abroad (on the Example of Almaty)

Internal migration is a transitional moment for young people to migrate abroad. This article aims to study city infrastructure as a factor influencing the internal migration of young people to big cities. This is one of the country’s problems because it results in a «brain drain» abroad. There is a need to consider these factors. The study examines young people involved in internal migration who arrived in Almaty, aged 14 - 29. The methodology of this study is based on the method of Everett S. Lee. It analyzes factors influencing the internal migration of young people to cities with a population of one million. The article discusses objective factors that constrain or stimulate the migration process between regions of the Republic of Kazakhstan. These factors include the number of universities and colleges, the number of employers, medical and entertainment institutions, etc. These indicators were grouped into four factors: education, health care, entertainment and employment. For data analysis and processing, generalization and systematization methods were used. Data for factor estimation was obtained from the National Bureau of Statistics and other official sources for the period 2014 - 2021. Correlation-regression analysis was conducted using the SPSS program to determine the relationship between internal migration and city infrastructure indicators. Results obtained showed a significant relationship between the internal migration of young people and educational and health organizations. Education is seen as one of the main factors in the internal and external migration of young people. Therefore, the development of higher education and employment rates is essential to prevent brain drain