Introduction. The purpose of the work is to obtain the protein fractions β-LG, α-LA and BSA from the milk whey by preparative disc-electrophoresis. Materials and methods. The whey was obtained from the fresh cow's milk after isoelectric precipitation of casein complex proteins. The concentration of whey proteins was determined on a spectrophotometer by the absorption at λ = 280 nm. Gel filtration was carried out on liquid chromatography columns. Sephadexes G-25 and G-100 were used for the gel filtration. The fractional composition and homogeneity of whey proteins were analyzed by disc-electrophoresis in the polyacrylamide gel slabs. Results and discussion. A system of disc-electrophoresis in native conditions for acidic and neutral proteins has been selected for the preparative isolation of homogeneous fractions of bioactive peptides proteins-precursors from milk whey taking into account the effectivety and existence of denaturation factors. A sample of whey proteins, for preparative fractionation purified, from low molecular weight compounds had been obtained at the result of the gel filtration. An optimal whey proteins sample amount should not exceed 10 ml to provide an effective separation in a modified electrophoretic chamber of Studier type apparatus. Too large sample amount does not allow to separate the whey proteins effectively and obtain the homogeneous fractions extraction. The duration of the extraction process of individual protein fractions after preparative discelectrophoresis was about 55-60 min. The degree of homogeneity of the obtained protein fractions was established with the help of analytical disc-electrophoresis. It was 95-97% for β-LG and BSA fractions and 89-91% for α-LA fractions. It has been calculated that the total yield of homogeneous milk whey protein fractions was nearly 49-61% (from milk whey proteins taken for separation). Conclusions. The proposed variant of the disc-electrophoresis allows to isolate from milk whey the electrophoretically homogeneous fractions of β-LG, α-LA and BSA in native conditions. The duration of electrophoresis and proteins extraction is about 4 hours. The average yield of homogeneous fractions from whey proteins is 55±6%.

In this paper, the authors attempted to answer the question about the reasons for the unsatisfactory state of learning outcomes in graduate school. A multidimensional typology of graduate students was carried out (using the example of Dubna State University) using cluster analysis with preliminary factor analysis. The authors identified the key latent factors: interaction with the supervisor, sociocultural potential, organization of work on the thesis, career opportunities underlying the cluster model. Inside the graduate community, there are four internally homogeneous clusters: “depressed”, “resource”, “disappointed”, and “random”. It is shown that the most promising from the point of view of scientific “growth” and the defense of the thesis are graduate students of the second group – “resource”. At the same time, the strongest motivational factors that act as a guarantor of the successful completion of postgraduate studies and defending a thesis are still the established interaction with the supervisor and interest in the research topic - the traditional “values” of any graduate student.

In this paper, the authors attempted to answer the question about the reasons for the unsatisfactory state of learning outcomes in graduate school. A multidimensional typology of graduate students was carried out (using the example of Dubna State University) using cluster analysis with preliminary factor analysis. The authors identified the key latent factors: interaction with the supervisor, sociocultural potential, organization of work on the thesis, career opportunities underlying the cluster model. Inside the graduate community, there are four internally homogeneous clusters: "Depressed", "Resource", "Disappointed", and "Random". It is shown that the most promising from the point of view of scientific "growth" and the defense of the thesis are graduate students of the second group-"resource". At the same time, the strongest motivational factors that act as a guarantor of the successful completion of postgraduate studies and defending a thesis are still the established interaction with the supervisor and interest in the research topicthe traditional "values" of any graduate student.