24 research outputs found

    Recent Developments in Calcium Alloy Cored Wire in Steel Production

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    The control of sulphides and oxides and desulphurisation by injection of calcium alloys in liquid steel is used with success in ladle now for many years. In the last years, technique of Ca alloys cored wire was developed as an alternative for inclusions control. A tehcnology using a wire, not welded with a large dia-meter is described so that feeder of the capstan type, making it possible to introduce big quantity of Ca alloys (SiCa-SiCaBa...) or other powdered products. This tech-nique is intended to small foundry ladles or big steel-works ladles as a tool to treat medium tonnages. Treatment in tundish of casters is also possible. Some results achieved in special steels for mechanical industry are given regarding mainly sulphides control by ladle addition

    The Transcription Factor YY1 Is a Substrate for Polo-Like Kinase 1 at the G2/M Transition of the Cell Cycle

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    Yin-Yang 1 (YY1) is an essential multifunctional zinc-finger protein. It has been shown over the past two decades to be a critical regulator of a vast array of biological processes, including development, cell proliferation and differentiation, DNA repair, and apoptosis. YY1 exerts its functions primarily as a transcription factor that can activate or repress gene expression, dependent on its spatial and temporal context. YY1 regulates a large number of genes involved in cell cycle transitions, many of which are oncogenes and tumor-suppressor genes. YY1 itself has been classified as an oncogene and was found to be upregulated in many cancer types. Unfortunately, our knowledge of what regulates YY1 is very minimal. Although YY1 has been shown to be a phosphoprotein, no kinase has ever been identified for the phosphorylation of YY1. Polo-like kinase 1 (Plk1) has emerged in the past few years as a major cell cycle regulator, particularly for cell division. Plk1 has been shown to play important roles in the G/M transition into mitosis and for the proper execution of cytokinesis, processes that YY1 has been shown to regulate also. Here, we present evidence that Plk1 directly phosphorylates YY1 in vitro and in vivo at threonine 39 in the activation domain. We show that this phosphorylation is cell cycle regulated and peaks at G2/M. This is the first report identifying a kinase for which YY1 is a substrate

    Effect of composition and deformation temperature on the annealing behavior of stacking faults in α-Cu-Ge alloys

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    The disappearance of stacking faults in filings of α-Cu-Ge alloys (5.6, 6.7, 7.7, and 8.5 at. pct Ge) prepared at various deformation temperatures has been studied with X-ray diffraction. The faults anneal out in two stages, the second of which is diffusion controlled. The time necessary to anneal out all of the faults depends on both alloy composition and deformation temperature. The dependence of the number of faults on the deformation temperature has also been determined

    Transcriptional coactivator HCF-1 couples the histone chaperone Asf1b to HSV-1 DNA replication components

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    The cellular transcriptional coactivator HCF-1 interacts with numerous transcription factors as well as other coactivators and is a component of multiple chromatin modulation complexes. The protein is essential for the expression of the immediate early genes of both herpes simplex virus (HSV) and varicella zoster virus and functions, in part, by coupling chromatin modification components including the Set1 or MLL1 histone methyltransferases and the histone demethylase LSD1 to promote the installation of positive chromatin marks and the activation of viral immediately early gene transcription. Although studies have investigated the role of HCF-1 in both cellular and viral transcription, little is known about other processes that the protein may be involved in. Here we demonstrate that HCF-1 localizes to sites of HSV replication late in infection. HCF-1 interacts directly and simultaneously with both HSV DNA replication proteins and the cellular histone chaperone Asf1b, a protein that regulates the progression of cellular DNA replication forks via chromatin reorganization. Asf1b localizes with HCF-1 in viral replication foci and depletion of Asf1b results in significantly reduced viral DNA accumulation. The results support a model in which the transcriptional coactivator HCF-1 is a component of the HSV DNA replication assembly and promotes viral DNA replication by coupling Asf1b to DNA replication components. This coupling provides a novel function for HCF-1 and insights into the mechanisms of modulating chromatin during DNA replication
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