258 research outputs found

    Extending the Real-Time Maude Semantics of Ptolemy to Hierarchical DE Models

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    This paper extends our Real-Time Maude formalization of the semantics of flat Ptolemy II discrete-event (DE) models to hierarchical models, including modal models. This is a challenging task that requires combining synchronous fixed-point computations with hierarchical structure. The synthesis of a Real-Time Maude verification model from a Ptolemy II DE model, and the formal verification of the synthesized model in Real-Time Maude, have been integrated into Ptolemy II, enabling a model-engineering process that combines the convenience of Ptolemy II DE modeling and simulation with formal verification in Real-Time Maude.Comment: In Proceedings RTRTS 2010, arXiv:1009.398

    An Actuarial Analysis of Calibration of Crop Insurance Premiums to Heterogeneous Risks

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    This paper examines whether the loadings on the crop insurance premium rates for risks such as moral hazard and adverse selection are adequate. From the discrete choice (tobit) analysis conducted, we discover that the premium loadings for 75% coverage level are not adequate, resulting in losses for the Risk Management Agency

    Early versus late rehabilitation for stroke survivors: A prospective study

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    The aim of this study was to examine the optimum time of rehabilitation initiation after stroke in terms of disabilities, mobility and fall risk assessment. Data were collected prospectively at seven tertiary level health care centers in Bangladesh during the 36 months period from 2013 to 2016. All respondents were divided into four groups based on the initiation of rehabilitation as: a) 0-24 hours, b) 25-72 hours, c) 4-7 days and d) 8-60 days. Results show that significant improvement on stroke recovery, disabilities reduction, improvement in mobility restriction and reduction of fall risks in all the four groups but more improvement was observed in 0-24 hour’s group during follow-up after 3 and 12 weeks. On multinomial logistic regression analysis, the independent factors shows the mobility restriction and fall risk were more in the younger patients, male gender, married, hemorrhagic lesion and bilateral stroke

    Modification of the L1-CAM carboxy-terminus in pancreatic adenocarcinoma cells

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    The neural cell adhesion molecule L1 has recently been shown to be expressed in pancreatic adenocarcinoma (PDAC) cells. In this report, we demonstrate that L1 is expressed by moderately- to poorly-differentiated PDAC cells in situ, and that L1 expression is a predictor of poor patient survival. In vitro, reduced reactivity of an anti-L1 carboxy-terminus-specific antibody was observed in the more poorly differentiated fast-growing (FG) variant of the COLO357 population, versus its well-differentiated slow-growing (SG) counterpart, even though they express equivalent total L1. The carboxy-terminus of L1 mediates binding to the MAP kinase-regulating protein RanBPM and mutation of T1247/S1248 within this region attenuates the expression of malignancy associated proteins and L1-induced tumorigenicity in mice. Therefore, we reasoned that the differential epitope exposure observed might be indicative of modifications responsible for regulating these events. However, epitope mapping demonstrated that the major determinant of binding was actually N1251; mutation of T1247 and S1248, alone or together, had little effect on C20 binding. Moreover, cluster assays using CD25 ectodomain/L1 cytoplasmic domain chimeras demonstrated the N1251-dependent, RanBPM-independent stimulation of erk phosphorylation in these cells. Reactivity of this antibody also reflects the differential exposure of extracellular epitopes in these COLO357 sublines, consistent with the previous demonstration of L1 ectodomain conformation modulation by intracellular modifications. These data further support a central role for L1 in PDAC, and define a specific role for carboxy-terminal residues including N1251 in the regulation of L1 activity in PDAC cells

    EAACI Biologicals Guidelines-Recommendations for severe asthma

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    Severe asthma imposes a significant burden on patients, families and healthcare systems. Management is difficult, due to disease heterogeneity, co-morbidities, complexity in care pathways and differences between national or regional healthcare systems. Better understanding of the mechanisms has enabled a stratified approach to the management of severe asthma, supporting the use of targeted treatments with biologicals. However, there are still many issues that require further clarification. These include selection of a certain biological (as they all target overlapping disease phenotypes), the definition of response, strategies to enhance the responder rate, the duration of treatment and its regimen (in the clinic or home-based) and its cost-effectiveness. The EAACI Guidelines on the use of biologicals in severe asthma follow the GRADE approach in formulating recommendations for each biological and each outcome. In addition, a management algorithm for the use of biologicals in the clinic is proposed, together with future approaches and research priorities.Peer reviewe

    Sox6 Is Necessary for Efficient Erythropoiesis in Adult Mice under Physiological and Anemia-Induced Stress Conditions

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    BACKGROUND: Definitive erythropoiesis is a vital process throughout life. Both its basal activity under physiological conditions and its increased activity under anemia-induced stress conditions are highly stimulated by the hormone erythropoietin. The transcription factor Sox6 was previously shown to enhance fetal erythropoiesis together and beyond erythropoietin signaling, but its importance in adulthood and mechanisms of action remain unknown. We used here Sox6 conditional null mice and molecular assays to address these questions. METHODOLOGY/PRINCIPAL FINDINGS: Sox6fl/flErGFPCre adult mice, which lacked Sox6 in erythroid cells, exhibited compensated anemia, erythroid cell developmental defects, and anisocytotic, short-lived red cells under physiological conditions, proving that Sox6 promotes basal erythropoiesis. Tamoxifen treatment of Sox6fl/flCaggCreER mice induced widespread inactivation of Sox6 in a timely controlled manner and resulted in erythroblast defects before reticulocytosis, demonstrating that impaired erythropoiesis is a primary cause rather than consequence of anemia in the absence of Sox6. Twenty five percent of Sox6fl/flErGFPCre mice died 4 or 5 days after induction of acute anemia with phenylhydrazine. The others recovered slowly. They promptly increased their erythropoietin level and amplified their erythroid progenitor pool, but then exhibited severe erythroblast and reticulocyte defects. Sox6 is thus essential in the maturation phase of stress erythropoiesis that follows the erythropoietin-dependent amplification phase. Sox6 inactivation resulted in upregulation of embryonic globin genes, but embryonic globin chains remained scarce and apparently inconsequential. Sox6 inactivation also resulted in downregulation of erythroid terminal markers, including the Bcl2l1 gene for the anti-apoptotic factor Bcl-xL, and in vitro assays indicated that Sox6 directly upregulates Bcl2l1 downstream of and beyond erythropoietin signaling. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that Sox6 is necessary for efficient erythropoiesis in adult mice under both basal and stress conditions. It is primarily involved in enhancing the survival rate and maturation process of erythroid cells and acts at least in part by upregulating Bcl2l1

    Tau, prions and Aβ: the triad of neurodegeneration

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    This article highlights the features that connect prion diseases with other cerebral amyloidoses and how these relate to neurodegeneration, with focus on tau phosphorylation. It also discusses similarities between prion disease and Alzheimer’s disease: mechanisms of amyloid formation, neurotoxicity, pathways involved in triggering tau phosphorylation, links to cell cycle pathways and neuronal apoptosis. We review previous evidence of prion diseases triggering hyperphosphorylation of tau, and complement these findings with cases from our collection of genetic, sporadic and transmitted forms of prion diseases. This includes the novel finding that tau phosphorylation consistently occurs in sporadic CJD, in the absence of amyloid plaques

    Cholera- and Anthrax-Like Toxins Are among Several New ADP-Ribosyltransferases

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    Chelt, a cholera-like toxin from Vibrio cholerae, and Certhrax, an anthrax-like toxin from Bacillus cereus, are among six new bacterial protein toxins we identified and characterized using in silico and cell-based techniques. We also uncovered medically relevant toxins from Mycobacterium avium and Enterococcus faecalis. We found agriculturally relevant toxins in Photorhabdus luminescens and Vibrio splendidus. These toxins belong to the ADP-ribosyltransferase family that has conserved structure despite low sequence identity. Therefore, our search for new toxins combined fold recognition with rules for filtering sequences – including a primary sequence pattern – to reduce reliance on sequence identity and identify toxins using structure. We used computers to build models and analyzed each new toxin to understand features including: structure, secretion, cell entry, activation, NAD+ substrate binding, intracellular target binding and the reaction mechanism. We confirmed activity using a yeast growth test. In this era where an expanding protein structure library complements abundant protein sequence data – and we need high-throughput validation – our approach provides insight into the newest toxin ADP-ribosyltransferases

    Food and Nutrition Security Indicators: A Review

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