50 research outputs found

    Research on Geometric Errors of Intermediate Unit Shell of a Geokhod

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    This article includes the research results on production errors of intermediate unit shell of a geokhod prototype model. There has been a problem stated concerning the accuracy of geokhod shells; constructive and technological particularities of a intermediate unit have been specified. A short summary has been conducted of the types of approach to the determination of shell errors of large equipment. The research was performed on the basis of data received by means of coordinate control of a gekhod prototype model in a production environment. The captured data have been researched by means of statistical methods and analyzed with the purpose of unveiling the factors affecting the errors. It was showed in the article that the errors can be partially explained by the production errors of body sectors and the errors of their relative assembling position. It was demonstrated that at least a part of errors is conditioned by reasons which are not taken into account in the process of a pure geometric description of the intermediate unit manufacturing process

    Research on Geometric Errors of Intermediate Unit Shell of a Geokhod

    Get PDF
    This article includes the research results on production errors of intermediate unit shell of a geokhod prototype model. There has been a problem stated concerning the accuracy of geokhod shells; constructive and technological particularities of a intermediate unit have been specified. A short summary has been conducted of the types of approach to the determination of shell errors of large equipment. The research was performed on the basis of data received by means of coordinate control of a gekhod prototype model in a production environment. The captured data have been researched by means of statistical methods and analyzed with the purpose of unveiling the factors affecting the errors. It was showed in the article that the errors can be partially explained by the production errors of body sectors and the errors of their relative assembling position. It was demonstrated that at least a part of errors is conditioned by reasons which are not taken into account in the process of a pure geometric description of the intermediate unit manufacturing process

    FOXA1 Directs H3K4 Monomethylation at Enhancers via Recruitment of the Methyltransferase MLL3

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    FOXA1 is a pioneer factor that binds to enhancer regions that are enriched in H3K4 mono- and dimethylation (H3K4me1 and H3K4me2). We performed a FOXA1 rapid immunoprecipitation mass spectrometry of endogenous proteins (RIME) screen in ERα-positive MCF-7 breast cancer cells and found histone-lysine N-methyltransferase (MLL3) as the top FOXA1-interacting protein. MLL3 is typically thought to induce H3K4me3 at promoter regions, but recent findings suggest it may contribute to H3K4me1 deposition. We performed MLL3 chromatin immunoprecipitation sequencing (ChIP-seq) in breast cancer cells, and MLL3 was shown to occupy regions marked by FOXA1 occupancy and H3K4me1 and H3K4me2. MLL3 binding was dependent on FOXA1, indicating that FOXA1 recruits MLL3 to chromatin. MLL3 silencing decreased H3K4me1 at enhancer elements but had no appreciable impact on H3K4me3 at enhancer elements. We propose a mechanism whereby the pioneer factor FOXA1 recruits the chromatin modifier MLL3 to facilitate the deposition of H3K4me1 histone marks, subsequently demarcating active enhancer elements.We would like to acknowledge the support of the University of Cambridge, Cancer Research UK and Hutchison Whampoa Limited. K.M.J. is funded by Cancer Research UK. J.S.C. is supported by an ERC consolidator grant (Number 646876) and an EMBO young investigator award

    A mathematical model of the layered plate throwing by detonation products

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    The problem of the layered plates throwing in the conditions of incomplete dispersal of detonation products (DP) is devoted to quite a lot of work, but this problem is usually solved either by various numerical methods, which in practice are not applicable due to the significant difficulties for calculations, or in one-dimensional form, that does not allows for the correct determination of pressure in DP and turn angles after the impact of the plates. This paper provides a mathematical model of multi-layered throwing calculation using fairly simple analytical equations to determine the above parameters when solving various applications for explosive processing of materials by a sliding detonation wave. © 2021 Author(s).The research was supported by Ministry of Science and Higher Education of the Russian Federation, state contract № 075-03-2020-582/4 and by Russian Foundation for Basic Research, project no. 20-08-00-00873

    Regulation of the apoptotic genes in breast cancer cells by the transcription factor CTCF

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    CTCF is a highly conserved and ubiquitous transcription factor with versatile functions. We previously demonstrated that elevated protein levels of CTCF in breast cancer cells were associated with the specific anti-apoptotic function of CTCF. We used proteomics and microarray approaches to identify regulatory targets of CTCF specific for breast cancer cells. Among the CTCF identified targets were proteins involved in the control of apoptosis. A proapoptotic protein, Bax, negatively regulated by CTCF, was chosen for further investigation. Repression of the human Bax gene at the transcriptional level by CTCF in breast cancer cells was confirmed by real-time PCR. Two CTCF binding sites within the Bax promoter were identified by electrophoretic mobility shift assay and footprinting. In reporter assays, the Bax-luciferase reporter construct, containing CTCF-binding sites, was negatively regulated by CTCF. In vivo, CTCF occupied its binding sites in breast cancer cells and tissues, as confirmed by chromatin immunoprecipitation assay. Our findings suggest a possible mechanism of the specific CTCF anti-apoptotic function in breast cancer cells whereby CTCF is bound to the Bax promoter, resulting in repression of Bax and inhibition of apoptosis; depletion of CTCF leads to activation of Bax and apoptotic death. CTCF binding sites in the Bax promoter are unmethylated in all cells and tissues inspected. Therefore, specific CTCF interaction with the Bax promoter in breast cancer cells, and the functional outcome, may depend on a combination of epigenetic factors characteristic for these cells. Interestingly, CTCF appears to be a negative regulator of other proapoptotic genes (for example, Fas, Apaf-1, TP531NP1). Conversely, stimulating effects of CTCF on the anti-apoptotic genes (Bcl-2, Bag-3) have been observed. Taken together, these findings suggest that specific mechanisms have evolved in breast cancer cells to protect them from apoptosis; regulation of apoptotic genes by CTCF appears to be one of the resistance strategies

    ARID1A influences HDAC1/BRD4 activity, intrinsic proliferative capacity and breast cancer treatment response.

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    Using genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screens to understand endocrine drug resistance, we discovered ARID1A and other SWI/SNF complex components as the factors most critically required for response to two classes of estrogen receptor-alpha (ER) antagonists. In this context, SWI/SNF-specific gene deletion resulted in drug resistance. Unexpectedly, ARID1A was also the top candidate in regard to response to the bromodomain and extraterminal domain inhibitor JQ1, but in the opposite direction, with loss of ARID1A sensitizing breast cancer cells to bromodomain and extraterminal domain inhibition. We show that ARID1A is a repressor that binds chromatin at ER cis-regulatory elements. However, ARID1A elicits repressive activity in an enhancer-specific, but forkhead box A1-dependent and active, ER-independent manner. Deletion of ARID1A resulted in loss of histone deacetylase 1 binding, increased histone 4 lysine acetylation and subsequent BRD4-driven transcription and growth. ARID1A mutations are more frequent in treatment-resistant disease, and our findings provide mechanistic insight into this process while revealing rational treatment strategies for these patients

    A Global Network of Science and Technology Advice in Foreign Ministries

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    This paper is a product of the International Dialogue on Science and Technology Advice in Foreign Ministries (Vienna Dialogue) in October 2016, involving more than twenty nations and several international organisations. The event was a key step to further develop the Foreign Minister Science and Technology Advisor Network (FMSTAN), growing from an initial group of five nations. The Vienna Dialogue was convened by the Fletcher School of Law and Diplomacy, Tufts University, and the International Institute for Applied Systems Analysis (IIASA) at the Vienna headquarters of IIASA, bringing together diplomats from foreign ministries to consider the value of evidence for informed decision-making by nations with regard to issues, impacts and resources within, across and beyond national boundaries. The evidence comes from the natural and social sciences with engineering and medicine as well as other areas of technology. By building common interests among nations, science is a tool of diplomacy, promoting cooperation and preventing conflict in our world. Science diplomacy was discussed as an international, interdisciplinary and inclusive process to help balance national interests and common interests in view of urgencies today and across generations in our globally-interconnected civilization

    BORIS, a paralogue of the transcription factor, CTCF, is aberrantly expressed in breast tumours

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    BORIS (for brother of the regulator of imprinted sites), a paralogue of the transcription factor, CTCF, is a novel member of the cancer-testis antigen family. The aims of the present study were as follows: (1) to investigate BORIS expression in breast cells and tumours using immunohistochemical staining, western and real-time RT–PCR analyses and (2) assess potential correlation between BORIS levels in tumours with clinical/pathological parameters. BORIS was detected in all 18 inspected breast cell lines, but not in a primary normal breast cell culture. In 70.7% (41 of 58 cases) BORIS was observed in breast tumours. High levels of BORIS correlated with high levels of progesterone receptor (PR) and oestrogen receptor (ER). The link between BORIS and PR/ER was further confirmed by the ability of BORIS to activate the promoters of the PR and ER genes in the reporter assays. Detection of BORIS in a high proportion of breast cancer patients implies potential practical applications of BORIS as a molecular biomarker of breast cancer. This may be important for diagnosis of the condition and for the therapeutic use of BORIS. The ability of BORIS to activate promoters of the RP and ER genes points towards possible involvement of BORIS in the establishment, progression and maintenance of breast tumours
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