424 research outputs found

    Вплив нормального тиску на напружений стан гуми ступінчастого каната на робочому органі підйомної машини

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    Досліджено напружений стан гуми ступінчастого гумотросового каната у разі його застосування на підйомній машині з бобінним робочим органом та зі шківом тертя. Показано, що максимальні напруження в гумі залежать від конструкції каната та тиску, що виникає поміж шарами. Форма поперечного перерізу троса також впливає на напружений стан гуми.Исследовано напряженное состояние резины ступенчатого резинотросового каната в случае его применения на подъемной машине с бобинным рабочим органом и со шкивом трения. Показано, что максимальные напряжения в резине зависят от конструкции каната и давления, возникающего между слоями. Форма поперечного сечения троса также влияет на напряженное состояние резины.The stress-strain state of stepped rubber-rope cable in bobbin of winding and in pulley friction, are investigated. Shown that the maximum stress in the rubber depends on the design of the rope and the pressure appeared between the layers. Cable cross-sectional shape also affects to the stressstrain state of rubber

    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

    A d10 Ag(i) amine-borane σ-complex and comparison with a d8 Rh(i) analogue : Structures on the η1 to η2:η2 continuum

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    H3B·NMe3 σ-complexes of d8 [(L1)Rh][BArF4] and d10 [(L1)Ag][BArF4] (where L1 = 2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine) have been prepared and structurally characterised. Analysis of the molecular and electronic structures reveal important but subtle differences in the nature of the bonding in these σ-complexes, which differ only by the identity of the metal centre and the d-electron count. With Rh the amine-borane binds in an η2:η2 fashion, whereas at Ag the unsymmetrical {Ag⋯H3B·NMe3} unit suggests a structure lying between the η2:η2 and η1 extremes

    The CADM1 tumor suppressor gene is a major candidate gene in MDS with deletion of the long arm of chromosome 11.

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    Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis leading to peripheral cytopenias and in a substantial proportion of cases to acute myeloid leukemia. The deletion of the long arm of chromosome 11, del(11q), is a rare but recurrent clonal event in MDS. Here, we detail the largest series of 113 cases of MDS and myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) harboring a del(11q) analyzed at clinical, cytological, cytogenetic, and molecular levels. Female predominance, a survival prognosis similar to other MDS, a low monocyte count, and dysmegakaryopoiesis were the specific clinical and cytological features of del(11q) MDS. In most cases, del(11q) was isolated, primary and interstitial encompassing the 11q22-23 region containing ATM, KMT2A, and CBL genes. The common deleted region at 11q23.2 is centered on an intergenic region between CADM1 (also known as Tumor Suppressor in Lung Cancer 1) and NXPE2. CADM1 was expressed in all myeloid cells analyzed in contrast to NXPE2. At the functional level, the deletion of Cadm1 in murine Lineage-Sca1+Kit+ cells modifies the lymphoid-to-myeloid ratio in bone marrow, although not altering their multilineage hematopoietic reconstitution potential after syngenic transplantation. Together with the frequent simultaneous deletions of KMT2A, ATM, and CBL and mutations of ASXL1, SF3B1, and CBL, we show that CADM1 may be important in the physiopathology of the del(11q) MDS, extending its role as tumor-suppressor gene from solid tumors to hematopoietic malignancies

    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

    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
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