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Search Results: 1 - 10 of 130728 matches for " Aleksandr V. Makeyev "
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Diversity and Complexity in Chromatin Recognition by TFII-I Transcription Factors in Pluripotent Embryonic Stem Cells and Embryonic Tissues
Aleksandr V. Makeyev, Badam Enkhmandakh, Seung-Hyun Hong, Pujan Joshi, Dong-Guk Shin, Dashzeveg Bayarsaihan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044443
Abstract: GTF2I and GTF2IRD1 encode a family of closely related transcription factors TFII-I and BEN critical in embryonic development. Both genes are deleted in Williams-Beuren syndrome, a complex genetic disorder associated with neurocognitive, craniofacial, dental and skeletal abnormalities. Although genome-wide promoter analysis has revealed the existence of multiple TFII-I binding sites in embryonic stem cells (ESCs), there was no correlation between TFII-I occupancy and gene expression. Surprisingly, TFII-I recognizes the promoter sequences enriched for H3K4me3/K27me3 bivalent domain, an epigenetic signature of developmentally important genes. Moreover, we discovered significant differences in the association between TFII-I and BEN with the cis-regulatory elements in ESCs and embryonic craniofacial tissues. Our data indicate that in embryonic tissues BEN, but not the highly homologous TFII-I, is primarily recruited to target gene promoters. We propose a “feed-forward model” of gene regulation to explain the specificity of promoter recognition by TFII-I factors in eukaryotic cells.
Lows of Wear Process of the Friction Pair “0.45% Carbon Steel—Polytetrafluoroethylene” during Sliding from the Position of Fracture Mechanics  [PDF]
Aleksandr V. Bogdanovich
World Journal of Mechanics (WJM) , 2019, DOI: 10.4236/wjm.2019.95007
Abstract: The results of the tests for a friction pair “a cylindrical specimen made of 0.45% carbon steel—a counter specimen-liner made of polytetrafluoroethyleneF4-B” during sliding friction are presented. The test results at different levels of contact load are analyzed using the Archard’s equation and are presented as a friction fatigue curve. The concept of the frictional stress intensity factor during sliding friction is introduced, and an expression that relates the wear rate to this factor and is close in shape to the Paris equation in fracture mechanics is proposed.
Regulation of mRNA Abundance by Polypyrimidine Tract-Binding Protein-Controlled Alternate 5′ Splice Site Choice
Fursham M. Hamid,Eugene V. Makeyev
PLOS Genetics , 2014, DOI: doi/10.1371/journal.pgen.1004771
Abstract: Alternative splicing (AS) provides a potent mechanism for increasing protein diversity and modulating gene expression levels. How alternate splice sites are selected by the splicing machinery and how AS is integrated into gene regulation networks remain important questions of eukaryotic biology. Here we report that polypyrimidine tract-binding protein 1 (Ptbp1/PTB/hnRNP-I) controls alternate 5′ and 3′ splice site (5′ss and 3′ss) usage in a large set of mammalian transcripts. A top scoring event identified by our analysis was the choice between competing upstream and downstream 5′ss (u5′ss and d5′ss) in the exon 18 of the Hps1 gene. Hps1 is essential for proper biogenesis of lysosome-related organelles and loss of its function leads to a disease called type 1 Hermansky-Pudlak Syndrome (HPS). We show that Ptbp1 promotes preferential utilization of the u5′ss giving rise to stable mRNAs encoding a full-length Hps1 protein, whereas bias towards d5′ss triggered by Ptbp1 down-regulation generates transcripts susceptible to nonsense-mediated decay (NMD). We further demonstrate that Ptbp1 binds to pyrimidine-rich sequences between the u5′ss and d5′ss and activates the former site rather than repressing the latter. Consistent with this mechanism, u5′ss is intrinsically weaker than d5′ss, with a similar tendency observed for other genes with Ptbp1-induced u5′ss bias. Interestingly, the brain-enriched Ptbp1 paralog Ptbp2/nPTB/brPTB stimulated the u5′ss utilization but with a considerably lower efficiency than Ptbp1. This may account for the tight correlation between Hps1 with Ptbp1 expression levels observed across mammalian tissues. More generally, these data expand our understanding of AS regulation and uncover a post-transcriptional strategy ensuring co-expression of a subordinate gene with its master regulator through an AS-NMD tracking mechanism.
Problems of Birds Sex Determination  [PDF]
Antonina V. Trukhina, Aleksandr F. Smirnov
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.615111
Abstract: Sex determination system in birds is characterized by a homo-(Neognatae) and heteromorphic (Paleognatae) sex chromosomes. Heterogametic sex is female (ZZ/ZW system). DMRT1 gene is a gene regarded as a main male sex determining factor in this group of animals. The question remains about the participation of other factors (HEMOGEN, AMH etc.) in appearance of testis, and the role of steroid hormones in formation of ovaries. Complete sex inversion is not typical for species with genotypic sex determination (GSD), although the effect of estrogen metabolites is noted for birds. For birds epigenetic mechanisms of regulation (methylation of DNA and non-coding RNA) have been described for sex controlling genes such as CYP19A1 and DMRT1.
Coitus in the Symbolic Language of Slavic Culture
Aleksandr V. Gura
Folklore : Electronic Journal of Folklore , 2005,
Abstract: Folk culture considers sexual intercourse unclean and dangerous and therefore applies many restrictions to it. Usually coitus is referred to with euphemisms and other substitutes that can be both neutral and expressive, or even humorous. Symbols of coitus in popular culture are numerous and diverse. Coitus is one of the most important objects of allegory among different types of human activity. In traditional popular culture it corresponds to a wide paradigm of behavioural symbols. The paradigm is built on the basis of motivating indicators reflecting the external properties of action: joining together, mobility, insertion, rhythm and repetitive action, oscillation, friction at close contact, etc. The basis of the symbolic meanings attributed to sexual intercourse as a means of magic of traditional popular culture is the similarity of physical sexual contact to social contacts (marriage, ritual relations), as well as metaphorical extrapolation of its natural result (conception of the fetus) to the results of human activity (harvest, cattle, big game hunting or fishing).
Study of Financial and Economic Effect From Introduction of Benefits in Milk-Food Subcomplex of the Agro-Industrial Complex Исследование финансово-экономического эффекта от внедрения льгот в молокопродовольственном подкомплексе АПК
Belosvet Aleksandr V.
Business Inform , 2013,
Abstract: The article studies efficiency of application of instruments of state regulation, which are directed at expansion of a list of expenses, which reduce tax obligations in the milk-food subcomplex of the agro-industrial complex of Ukraine. It studies a possibility of reduction of fiscal load on agricultural producers by means of reduction of the tax base. The author identifies an economic effect from application of a preference by the subjects of the milk-food subcomplex of the agro-industrial complex. The article contains calculation of the increase of tax proceeds by the income tax and increase of tax proceeds into the budget for UAH 1,000 of the provided benefit. It identifies disadvantages of the studied preference and directions of its improvement. В статье исследована эффективность применения инструментов государственного регулирования, которые направлены на расширение перечня расходов, уменьшающих налоговые обязательства в молокопродовольственном подкомплексе АПК Украины. Предметной областью исследования является возможность уменьшения фискальной нагрузки на сельскохозяйственных товаропроизводителей за счет сокращения налоговой базы. Автором определен экономический эффект от применения преференции субъектами молокопродовольственного подкомплекса АПК. В статье рассчитан прирост налоговых поступлений по налогу на прибыль и прирост налоговых поступлений в бюджет в расчете на 1 тыс. грн предоставленной льготы. Определены недостатки исследуемой преференции и направления её усовершенствования.
Imperatives and Prerequisites of Introduction of Mechanisms of Realisation of Investment Construction Projects on the Basis of State-Private Partnership Императивы и предпосылки внедрения механизмов реализации инвестиционно-строительных проектов на основе государственно-частного партнерства
Dikiy Aleksandr V.
Business Inform , 2013,
Abstract: The article shows specific features of development of foreign projects of state-private partnership (SPP), types and forms of the used SPP models, also reveals modern problems and obstacles on the way of introduction of SPP, and provides recommendations on how to overcome them in construction industry in Ukraine. It provides theoretical build-ups and practical tools of managing investment activity of companies. It considers problems of investment management with respect to development and introduction of an organisational and economic mechanism of realisation of investment construction projects on the basis of SPP. It pays attentions to perfection of the process of formation and realisation of investment strategy by construction companies, justification of theoretical and instrumental procedures of the process of development and making investment decisions, development of analytical tools of project financing on the basis of foreign experience of the use of concession forms of partnership between the state and private business and its application in the investment construction sphere in modern conditions. В данной статье представлены особенности развития зарубежных проектов государственно-частного партнерства (ГЧП), виды и формы используемых моделей ГЧП, а также выявлены современные проблемы и препятствия на пути внедрения ГЧП, приведены рекомендации их преодоления в строительной отрасли Украины. Представлены теоретические наработки и практический инструментарий управления инвестиционной деятельностью предприятий. Рассмотрена проблематика инвестиционного менеджмента относительно разработки и внедрения организационно-экономического механизма реализации инвестиционно-строительных проектов на основе ГЧП. Внимание уделено усовершенствованию процесса формирования и реализации инвестиционной стратегии предприятиями строительной отрасли, обоснованию теоретико-инструментальных процедур процесса разработки и принятия инвестиционных решений, разработке аналитического инструме
Birational geometry of algebraic varieties with a pencil of Fano complete intersections
Aleksandr V. Pukhlikov
Mathematics , 2005,
Abstract: We prove birational superrigidity of generic Fano fiber spaces $V/{\mathbb P}^1$, the fibers of which are Fano complete intersections of index 1 and dimension $M$ in ${\mathbb P}^{M+k}$, provided that $M\geq 2k+1$. The proof combines the traditional quadratic techniques of the method of maximal singularities with the linear techniques based on the connectedness principle of Shokurov and Koll\' ar. Certain related results are also considered.
Birationally rigid varieties with a pencil of Fano double covers. III
Aleksandr V. Pukhlikov
Mathematics , 2005, DOI: 10.1070/SM2006v197n03ABEH003761
Abstract: We complete the study of birational geometry of Fano fiber spaces $\pi\colon V\to {\mathbb P}^1$, the fiber of which is a Fano double hypersurface of index 1. For each family of these varieties we either prove birational rigidity or produce explicitly non-trivial structures of Fano fiber spaces. A new linear method of studying movable systems on Fano fiber spaces $V/{\mathbb P}^1$ is developed.
Birationally rigid Fano fibre spaces. II
Aleksandr V. Pukhlikov
Mathematics , 2014, DOI: 10.1070/IM2015v079n04ABEH002762
Abstract: In this paper we prove birational rigidity of large classes of Fano-Mori fibre spaces over a base of arbitrary dimension, bounded from above by a constant that depends on the dimension of the fibre only. In order to do that, we first show that if every fibre of a Fano-Mori fibre space satisfies certain natural conditions, then every birational map onto another Fano-Mori fibre space is fibre-wise. After that we construct large classes of fibre spaces (into Fano double spaces of index one and into Fano hypersurfaces of index one) which satisfy those conditions. The paper is a follow up of my previous work: Pukhlikov A.V., Birationally rigid Fano fibrations, Izvestiya: Mathematics {\bf 64} (2000), No. 3, 563-581.
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