Quantitative investigation of reproduction of gonosomal condensed chromatin during trophoblast cell polyploidization and endoreduplication in the east-european field vole Microtus rossiaemeridionalis

Simultaneous determinations of DNA content in cell nuclei and condensed chromatin bodies formed by heterochromatized regions of sex chromosomes (gonosomal chromatin bodies, GCB) have been performed in two trophoblast cell populations of the East-European field vole Microtus rossiaemeridionalis: in the proliferative population of trophoblast cells of the junctional zone of placenta and in the secondary giant trophoblast cells. One or two GCBs have been observed in trophoblast cell nuclei of all embryos studied (perhaps both male and female). In the proliferative trophoblast cell population characterized by low ploidy levels (2–16c) and in the highly polyploid population of secondary giant trophoblast cells (32–256c) the total DNA content in GCB increased proportionally to the ploidy level. In individual GCBs the DNA content also rose proportionally to the ploidy level in nuclei both with one and with two GCBs in both trophoblast cell populations. Some increase in percentage of nuclei with 2–3 GCBs was shown in nuclei of the placenta junctional zone; this may be accounted for by genome multiplication via uncompleted mitoses. In nuclei of the secondary giant trophoblast cells (16–256c) the number of GCBs did not exceed 2, and the fraction of nuclei with two GCBs did not increase, which suggests the polytene nature of sex chromosomes in these cells. In all classes of ploidy the DNA content in trophoblast cell nuclei with the single GCB was lower than in nuclei with two and more GCBs. This can indicate that the single GCB in many cases does not derive from fusion of two GCBs. The measurements in individual GCBs suggest that different heterochromatized regions of the X- and Y-chromosome may contribute in GCB formation

Genome Modifications Involved in Developmental Programs of the Placental Trophoblast

The placental trophoblast cells give an example of profound genome modifications that lead to whole-genome multiplication, aneuploidy, under-replication of some genes or their clusters as well as, by contrast, gene amplification. These events are included into program of differentiation of functionally different cell lineages. In some cases the trophoblast cell differentiation involves depolyploidization achieved by non-mitotic division. Aneuploidy may be also accounted for by the unusual mitoses characteristic of Invertebrates and plants; in mammalian it may result from hypomethylation of centromere chromosome regions. The giant (endopolyploid) trophoblast cells organization includes “loose nucleosomes” accounted for by the non-canonical histone variants, i.e. H2AX, H2AZ, and H3. 3 . In the human extravillous trophoblast cells that, like murine TGC, invade endometrium, there occured significant changes of methylation as compared to non-invasive trophoblast cell populations . Meantime, some genes show hypermethylation connected with start of trophoblast lineages specification. Thus, despite the limited possibilities of chromosome visualization trophoblast cells represent an interesting model to investigate the role of modification of gene copy number and their expression that is important for the normal or abnormal cell differentiation

Multicomponent Educational Environment Preschool Educational Institution, as a Mean of Pupils' Development

The article is devoted to the consideration of multicomponent educational environment of preschool educational institution as a means of development of pupils. As a result of changes in the requirements for educational activities, there was a need to create a multi-component educational environment for preschool children. The purpose of this problem, the creation of a model of a multicomponent educational environment for preschool educational institutions. Based on the data of the study, a secondary analysis of the components of the educational environment of a preschool educational institution was carried out. As a result of this analysis, the task of creating a model of a multicomponent educational environment was set.Статья посвящена теме рассмотрения многокомпонентной образовательной среды дошкольного образовательного учреждения, как средства развития воспитанников. В результате изменения требований к образовательной деятельности, возникла необходимость создания для детей дошкольного возраста, многокомпонентной образовательной среды. Цель рассмотрения данной проблемы, создание модели многокомпонентной образовательной среды для дошкольного образовательного учреждения. На основе данных исследования, был проведѐн вторичный анализ компонентов образовательной среды дошкольного образовательного учреждения. В результате данного анализа была поставлена задача создания теоретической модели многокомпонентной образовательной среды

Intumescent compounds for fireproofing of polymer pipelines

Reducing the rate of fire spread in buildings through the intersections of enclosing building structures with polymer pipelines is achieved by using fire clutches equipped with liners made of expandable materials. In case of a fire, it is ensured that the spread of flame through polymer pipelines is hindered due to formation of a heat-insulating foamed layer. This layer does not allow the polymer low-melting pipelines to heat up to 120°C. Comparative assessment of heat-insulating and mechanical properties of two intumescent composites and their charred products were carried out to clarify the reasons for their heat-insulating efficiency. Composites included the same intumescent system (ammonium polyphosphate / pentaerythritol / dolomite / thermally expanded graphite) and different polymer binders. The research was conducted using the following methods: complex thermal and X-ray analyses, scanning electron microscopy, a number of standard and original techniques. It was established that heat-insulating ability of a charred layer is determined by temperature intervals in which interactions of initial components occur. The best mechanical, heat-insulating and morphological properties of investigated intumescent composites and their charred layers are achieved when temperature ranges referred to formation of organo-mineral framework and volatile thermolysis products are coinciding. For the composites studied in this paper, this temperature range was 350–400 °C. Thanks to this knowledge, it becomes possible to develop new fire-retardant composites with improved properties instead of selecting the components in empirical way. As a result, the general quality of fire-retardant materials may grow and their properties will be sufficient not only to meet the construction requirements, but to properly operate in case of fire as well, practically justifying the predicted effect

Sentiment Analysis Based on Machine Learning Algorithms

This article reveals principles of sentiment analysis in text based on supervised learning algorithms. In particular, the Naive Bayes Classifier algorithm is chosen as an example. Also, the article considers steps of preparing data for the analysis.В статье рассмотрены принципы анализа тональности текста на основе алгоритмов обучения с учителем. Выбранным алгоритмом является наивный классификатор Байеса. Также, рассмотрен процесс подготовки данных к анализу

Methodological aspects of adaptive physical culturein weaken children

В статье описаны адаптированные тесты для слабовидящих детей при оценке уровня статического и динамического равновесия, мелкой моторики рук и координационных способностей.The article describes adapted tests for visually impaired children in assessing the level of static and dynamic balance, fine motor skills and coordination abilities

Appliance of electronic educational resources in the educational process of a higher education institute

The article covers the possibility of appliance of EER (Electronic Educational Resources) in students’ engagementРассматривается возможность применения электронных образовательных ресурсов (ЭОР) в работе со студентам