572 research outputs found

    Rewriting systems and biautomatic structures for Chinese, hypoplactic, and sylvester monoids

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    This paper studies complete rewriting systems and biautomaticity for three interesting classes of finite-rank homogeneous monoids: Chinese monoids, hypoplactic monoids, and sylvester monoids. For Chinese monoids, we first give new presentations via finite complete rewriting systems, using more lucid constructions and proofs than those given independently by Chen & Qui and Güzel Karpuz; we then construct biautomatic structures. For hypoplactic monoids, we construct finite complete rewriting systems and biautomatic structures. For sylvester monoids, which are not finitely presented, we prove that the standard presentation is an infinite complete rewriting system, and construct biautomatic structures. Consequently, the monoid algebras corresponding to monoids of these classes are automaton algebras in the sense of Ufnarovskij

    The PI3K p110α isoform regulates endothelial adherens junctions via Pyk2 and Rac1

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    Only the p110α isoform of PI3K mediates the association of VE-cadherin with Pyk2, a Rac GEF and the p85 PI3K regulatory subunit, to reduce junctional integrity in response to TNF

    Does Revlon Matter? A Empirical and Theoretical Study

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    We empirically examine whether and how the doctrine of enhanced judicial scrutiny that emerged from Revlon and its progeny actually affects M&A transactions. Combining hand-coding and machine-learning techniques, we assemble data from the proxy statements of publicly announced mergers between 2003 and 2017 into a dataset of 1,913 unique transactions. Of these, 1,167 transactions were subject to the Revlon standard, and 553 were not. After subjecting this sample to empirical analysis, our results show that Revlon does indeed matter for companies incorporated in Delaware. We find that in Delaware, Revlon deals are more intensely negotiated, involve more bidders, and result in higher transaction premiums than non-Revlon deals. However, these results do not hold for target companies incorporated in other jurisdictions that have adopted the Revlon doctrine. Our results shed light on the implications of the current state of uncertainty surrounding Revlon and provide some direction for courts going forward. We theorize that Revlon is a monitoring standard whose effectiveness depends upon the judiciary’s credible commitment to intervene in biased transactions. The precise contours of the doctrine are unimportant as long as the judiciary retains a substantive avenue for intervention. Recent Delaware decisions in C&J and Corwin have been criticized for overly restricting Revlon, but we suggest that such concerns are overstated so long as Delaware judges continue to monitor the substance of transactions. Thus, in applying these decisions, Delaware judges should focus not on procedural aspects but the substantive component of transactions, which Revlon initially sought to regulate

    The differential regulation of Lck kinase phosphorylation sites by CD45 is critical for T cell receptor signaling responses

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    SummaryThe molecular mechanisms whereby the CD45 tyrosine phosphatase (PTPase) regulates T cell receptor (TCR) signaling responses remain to be elucidated. To investigate this question, we have reconstituted CD45 (encoded by Ptprc)-deficient mice, which display severe defects in thymic development, with five different expression levels of transgenic CD45RO, or with mutant PTPase null or PTPase-low CD45R0. Whereas CD45 PTPase activity was absolutely required for the reconstitution of thymic development, only 3% of wild-type CD45 activity restored T cell numbers and normal cytotoxic T cell responses. Lowering the CD45 expression increased CD4 lineage commitment. Peripheral T cells with very low activity of CD45 phosphatase displayed reduced TCR signaling, whereas intermediate activity caused hyperactivation of CD4+ and CD8+ T cells. These results are explained by a rheostat mechanism whereby CD45 differentially regulates the negatively acting pTyr-505 and positively acting pTyr-394 p56lck tyrosine kinase phosphorylation sites. We propose that high wild-type CD45 expression is necessary to dephosphorylate p56lck pTyr-394, suppressing CD4 T+ cell lineage commitment and hyperactivity

    A preliminary audit of medical and aid provision in English Rugby union clubs:compliance with Regulation 9

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    BackgroundGoverning bodies are largely responsible for the monitoring and management of risks associated with a safe playing environment, yet adherence to regulations is currently unknown. The aim of this study was to investigate and evaluate the current status of medical personnel, facilities, and equipment in Rugby Union clubs at regional level in England.MethodsA nationwide cross-sectional survey of 242 registered clubs was undertaken, where clubs were surveyed online on their current medical personnel, facilities, and equipment provision, according to regulation 9 of the Rugby Football Union (RFU).ResultsOverall, 91 (45. 04%) surveys were returned from the successfully contacted recipients. Of the completed responses, only 23.61% (n = 17) were found to be compliant with regulations. Furthermore, 30.56% (n = 22) of clubs were unsure if their medical personnel had required qualifications; thus, compliance could not be determined. There was a significant correlation (p = −0.029, r = 0.295) between club level and numbers of practitioners. There was no significant correlation indicated between the number of practitioners/number of teams and number of practitioners/number of players. There were significant correlations found between club level and equipment score (p = 0.003, r = −0.410), club level and automated external defibrillator (AED) access (p = 0.002, r = −0.352) and practitioner level and AED access (p = 0.0001, r = 0.404). Follow-up, thematic analysis highlighted widespread club concern around funding/cost, awareness, availability of practitioners and AED training.ConclusionThe proportion of clubs not adhering overall compliance with Regulation 9 of the RFU is concerning for player welfare, and an overhaul, nationally, is required

    Radiographs in Clinical Periodontal Trials

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141530/1/jper0381.pd

    Deciphering interplay between Salmonella invasion effectors

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    Bacterial pathogens have evolved a specialized type III secretion system (T3SS) to translocate virulence effector proteins directly into eukaryotic target cells. Salmonellae deploy effectors that trigger localized actin reorganization to force their own entry into non-phagocytic host cells. Six effectors (SipC, SipA, SopE/2, SopB, SptP) can individually manipulate actin dynamics at the plasma membrane, which acts as a ‘signaling hub’ during Salmonella invasion. The extent of crosstalk between these spatially coincident effectors remains unknown. Here we describe trans and cis binary entry effector interplay (BENEFIT) screens that systematically examine functional associations between effectors following their delivery into the host cell. The results reveal extensive ordered synergistic and antagonistic relationships and their relative potency, and illuminate an unexpectedly sophisticated signaling network evolved through longstanding pathogen–host interaction
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