371 research outputs found

    Theoretical study of peculiarities of unstable longitudinal shear crack growth in sub-Rayleigh and supershear regimes

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    In the paper we present the results of the theoretical study of some fundamental aspects of mode II crack propagation in conventional sub-Rayleigh regime and transition to intersonic regime. It is shown that development of a sub-Rayleigh shear crack is determined in many respects by elastic vortex traveling ahead of the crack tip at a shear wave velocity. Formation of such a vortex helps to better understand the well-known phenomenon of acceleration of a shear crack towards the longitudinal wave velocity. Simulation results have shown that due to self-similarity of shear crack propagation the conditions of sub-Rayleigh to intersonic transition depend on dimensionless material and crack parameters. Two key dimensionless parameters are proposed

    Mechanistic Studies of Ethylene Hydrophenylation Catalyzed by Bipyridyl Pt(II) Complexes

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    This article discusses mechanistic studies of ethylene hydrophenylation catalyzed by bipyridyl Pt(II) complexes

    TET1 is a tumor suppressor of hematopoietic malignancy

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    The methylcytosine dioxygenase TET1 (‘ten-eleven translocation 1’) is an important regulator of 5-hydroxymethylcytosine (5hmC) in embryonic stem cells. The diminished expression of TET proteins and loss of 5hmC in many tumors suggests a critical role for the maintenance of this epigenetic modification. Here we found that deletion of Tet1 promoted the development of B cell lymphoma in mice. TET1 was required for maintenance of the normal abundance and distribution of 5hmC, which prevented hypermethylation of DNA, and for regulation of the B cell lineage and of genes encoding molecules involved in chromosome maintenance and DNA repair. Whole-exome sequencing of TET1-deficient tumors revealed mutations frequently found in non-Hodgkin B cell lymphoma (B-NHL), in which TET1 was hypermethylated and transcriptionally silenced. Our findings provide in vivo evidence of a function for TET1 as a tumor suppressor of hematopoietic malignancy.National Institutes of Health (U.S.) (5RO1HD045022)National Institutes of Health (U.S.) (5R37CA084198
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