34 research outputs found

    Modelling of outbursts and ejections occurrences during steel production

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    The application of small industrial cameras linked to a computer to create models for monitoring of adverse events in the steel making process is referenced. Presented models were created by analyzing video recordings that were captured in areas that could directly threaten human life. In laboratory conditions it is possible to analyze the recorded data and then already known mathematical methods are used to evaluate phenomena that are characterized in operating conditions by rapid pace and their monitoring on site is difficult and dangerous

    Influence of foundry dust on moulding mixtures quality

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    The objective of this paper was to observe the effect of the addition of the dust from the moulding plant on the quality parameters of the moulding mixtures and determine tolerable content in the moulding mixture. Three types of moulding mixtures were used in experiments: mixture prepared from new quartz sand and bentonite, mixture which is recycled in the experimental foundry and mixture came from the small foundry. To these moulding mixture was added the dust from moulding plant in the range 0 – 10%. Influence of dust addition on the compression strength, splitting strength and permeability was observed in all three kinds of mixtures

    Twin boundaries in d-wave superconductors

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    Twin boundaries in orthorhombic d-wave superconductors are investigated numerically using the Bogoliubov-deGennes formalism within the context of an extended Hubbard model. The twin boundaries are represented by tetragonal regions of variable width, with a reduced chemical potential. For sufficiently large twin boundary width and change in chemical potential, an induced s-wave component may break time-reversal symmetry at a low temperature. This temperature, and the magnitude of the complex component, are found to depend strongly on electron density. The results are compared with recent tunneling measurements.Comment: ReVTeX, 4 pages, 4 postscript figure

    Bcl-xL Deamidation Is a Critical Switch in the Regulation of the Response to DNA Damage

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    AbstractThe therapeutic value of DNA-damaging antineoplastic agents is dependent upon their ability to induce tumor cell apoptosis while sparing most normal tissues. Here, we show that a component of the apoptotic response to these agents in several different types of tumor cells is the deamidation of two asparagines in the unstructured loop of Bcl-xL, and we demonstrate that deamidation of these asparagines imports susceptibility to apoptosis by disrupting the ability of Bcl-xL to block the proapoptotic activity of BH3 domain-only proteins. Conversely, Bcl-xL deamidation is actively suppressed in fibroblasts, and suppression of deamidation is an essential component of their resistance to DNA damage-induced apoptosis. Our results suggest that the regulation of Bcl-xL deamidation has a critical role in the tumor-specific activity of DNA-damaging antineoplastic agents

    A Concerted HIF-1α/MT1-MMP Signalling Axis Regulates the Expression of the 3BP2 Adaptor Protein in Hypoxic Mesenchymal Stromal Cells

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    Increased plasticity, migratory and immunosuppressive abilities characterize mesenchymal stromal cells (MSC) which enable them to be active participants in the development of hypoxic solid tumours. Our understanding of the oncogenic adaptation of MSC to hypoxia however lacks the identification and characterization of specific biomarkers. In this study, we assessed the hypoxic regulation of 3BP2/SH3BP2 (Abl SH3-binding protein 2), an immune response adaptor/scaffold protein which regulates leukocyte differentiation and motility. Gene silencing of 3BP2 abrogated MSC migration in response to hypoxic cues and generation of MSC stably expressing the transcription factor hypoxia inducible factor 1alpha (HIF-1α) resulted in increased endogenous 3BP2 expression as well as cell migration. Analysis of the 3BP2 promoter sequence revealed only one potential HIF-1α binding site within the human but none in the murine sequence. An alternate early signalling cascade that regulated 3BP2 expression was found to involve membrane type-1 matrix metalloproteinase (MT1-MMP) transcriptional regulation which gene silencing abrogated 3BP2 expression in response to hypoxia. Collectively, we provide evidence for a concerted HIF-1α/MT1-MMP signalling axis that explains the induction of adaptor protein 3BP2 and which may link protein binding partners together and stimulate oncogenic MSC migration. These mechanistic observations support the potential for malignant transformation of MSC within hypoxic tumour stroma and may contribute to evasion of the immune system by a tumour

    Thermal conductivities and thermal runaways of superconducting MgB<sub>2</sub> wires stabilized by an Al + Al<sub>2</sub>O<sub>3</sub> sheath

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    This paper presents a study of the thermal transport properties of extra-light MgB2/Ti/Al + Al2O3 composite wires. The longitudinal thermal conductivity has been investigated as a function of temperature and magnetic field on wires differing only by an outer Al + Al2O3 sheath. The correlation between the thermal transport properties, the microstructure of the Al + Al2O3 sheath and the Al/Ti interface reactions provide important information for these thermally stabilized extra-light superconductors. The thermal runaways observed by the current–voltage characteristics of MgB2/Ti/Al + Al2O3 wires correlate well with the conductor's temperature affected by the thermal conductivity and the resistance of the outer sheath

    Growth and Structure of Buffer Layers for High Temperature Superconducting Films

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    We have studied thin CeO2\text{}_{2} buffer layers prepared by aerosol MOCVD on (11̅02) Al2\text{}_{2}O3\text{}_{3} substrate at high deposition temperature, Td\text{}_{d}= 900°C. A texture analysis by X-ray diffraction showed a high degree of epitaxial character of CeO2\text{}_{2} films. A study of the microstructure by transmission electron microscopy revealed that the CeO2\text{}_{2} films are in a relaxed state being composed of slightly misoriented blocks surrounded by dislocations. The films are smooth, giving mean square root values of the surface roughness measured by atomic force microscopy up to 1 nm

    shRNA-Mediated Decreases in c-Met Levels Affect the Differentiation Potential of Human Mesenchymal Stem Cells and Reduce Their Capacity for Tissue Repair

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    Mesenchymal stem cells/marrow stromal cells (MSC) are adult multipotent cells that can augment tissue repair. We previously demonstrated that culturing MSC in hypoxic conditions causes upregulation of the hepatocyte growth factor (HGF) receptor c-Met, allowing them to respond more robustly to HGF. MSC preconditioned in hypoxic environments contributed to restoration of blood flow after an ischemic injury more rapidly than MSC cultured in normoxic conditions. We now investigated the specific role of HGF/c-Met signaling in MSC function. An shRNA-mediated knockdown (KD) of c-Met in MSC did not alter their phenotypic profile, proliferation, or viability in vitro. However, we determined that while HGF/c-Met signaling does not play a role in the adipogenic differentiation of the cells, the disruption of this signaling pathway inhibited the ability of MSC to differentiate into the osteogenic and chondrogenic lineages. We next assessed the impact of c-Met KD on human MSC function in a xenogeneic hindlimb ischemia injury model. A 70% KD of c-Met in MSC resulted in a significant decrease in their capacity to regenerate blood flow to the ischemic limb, as compared to the MSC transduced with control shRNA. MSC with only a 60% KD of c-Met exhibited an intermediate capacity to restore blood flow, suggesting that MSC function is sensitive to the dosage of c-Met signaling. The current study highlights the significance of HGF/c-Met signaling in the capacity of MSC to restore blood flow after an ischemic injury and in their ability to differentiate into the osteogenic and chondrogenic lineages

    Bottom-up signaling from HGF-containing surfaces promotes hepatic differentiation of mesenchymal stem cells

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    The capacity of stem cells to differentiate into specific cell types makes them very promising in tissue regeneration and repair. However, realizing this promise requires novel methods for guiding lineage-specific differentiation of stem cells. In this study, hepatocyte growth factor (HGF), an important morphogen in liver development, was co-printed with collagen I (Col) to create arrays of protein spots on glass. Human adipose stem cells (ASCs) were cultured on top of the HGF/Col spots for 2 weeks. The effects of surface-immobilized HGF on hepatic differentiation of ASCs were analyzed using RT-PCR, ELISA and immunocytochemistry. Stimulation of stem cells with HGF from the bottom-up caused an upregulation in synthesis of α-fetoprotein and albumin, as determined by immunocytochemistry and ELISA. RT-PCR results showed that the mRNA levels for albumin, α-fetoprotein and α1 antitrypsin were 10 to 20 fold higher in stem cells cultured on the HGF/Col arrays compared to stem cells on Col only spots. Our results show that surfaces containing HGF co-printed with ECM proteins may be used to differentiate mesenchymal stem cells such as ASCs into hepatocyte-like cells. These results underscore the utility of growth factor-containing culture surfaces for stem cell differentiation
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