789 research outputs found

    A regression-based damage detection method for structures subjected to changing environmental and operational conditions

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    © 2020 Elsevier Ltd Damage detection of civil engineering structures during the past decade has focused on eliminating the effects of the changing environmental and operational conditions, from the effects of damage. In the literature, a regression analysis has been adopted to construct a model between the vibration properties of structures, and the environmental and operational parameters to represent the undamaged state of the structures, for damage detection. However, using the environmental and operational parameters in the analysis has several limitations. For example, these parameters are not always available which may affect the performances of the damage detection methods. Regression between the vibration properties only has also been proposed in the literature where multivariate statistical tools have been adopted to extract the relationships among the properties. However, these methods have the problem that it is more difficult to detect damage in the multivariate situations and a regression target is usually needed, which is difficult to determine. Therefore, a damage detection method which uses the simple regression analysis, is developed in this paper. The vibration properties of structures are used as both the independent and dependent variables in the developed method. This has the advantages that the environmental and operational conditions are not needed and the multivariate statistical tools are not required for data processing. The developed method is applied to a beam structure model and the Z24 Bridge, in Switzerland, and the results obtained demonstrate that the method can successfully classify between undamaged and damaged states. The traditional regression analysis method is also applied to the two structures and it was found that better results are obtained using the method developed in this paper

    Withaferin A activates TRIM16 for its anti‐cancer activity in melanoma

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    Although selective BRAF inhibitors and novel immunotherapies have improved short-term treatment responses in metastatic melanoma patients, acquired resistance to these therapeutics still represent a major challenge in clinical practice. In this study, we evaluated the efficacy of Withaferin A (WFA), derived from the medicinal plant Withania Somnifera, as a novel therapeutic agent for the treatment of melanoma. WFA showed selective toxicity to melanoma cells compared to non-malignant cells. WFA induced apoptosis, significantly reduced cell proliferation and inhibited migration of melanoma cells. We identified that repression of the tumour suppressor TRIM16 diminished WFA cytotoxicity, suggesting that TRIM16 was in part responsible for the cytotoxic effects of WFA in melanoma cells. Together our data indicates that WFA has potent cytopathic effects on melanoma cells through TRIM16, suggesting a potential therapeutic application of WFA in the disease

    Synchrotron and inverse-Compton emission from blazar jets I: a uniform conical jet model

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    In the first of a series of papers investigating emission from blazar jets from radio to high-energy {\gamma}-rays, we revisit the class of models where the jet has a uniform conical ballistic structure. We argue that by using simple developments of these models, in the context of new multi-frequency data extending to gamma-ray energies, valuable insights may be obtained into the properties that fully realistic models must ultimately have. In this paper we consider the synchrotron and synchrotron-self-Compton emission from the jet, modelling the recent simultaneous multi-wavelength observations of BL Lac. This is the first time these components have been fitted simultaneously for a blazar using a conical jet model. In the model we evolve the electron population dynamically along the jet taking into account the synchrotron and inverse-Compton losses. The inverse-Compton emission is calculated using the Klein-Nishina cross section and a relativistic transformation into the jet frame, and we explicitly show the seed photon population. We integrate synchrotron opacity along the line of sight through the jet plasma, taking into account the emission and opacity of each section of the jet. In agreement with previous studies of radio emission, we find that a conical jet model which conserves magnetic energy produces the characteristic blazar flat radio spectrum, however, we do not require any fine-tuning of the model to achieve this. Of particular note, in our model fit to BL Lac--which at ~10^37W is a relatively low jet-power source--we find no requirement for significant re-acceleration within the jet to explain the observed spectrum.Comment: 11 pages, 6 figures, accepted for publication in MNRA

    Structural requirements for PACSIN/Syndapin operation during zebrafish embryonic notochord development.

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    PACSIN/Syndapin proteins are membrane-active scaffolds that participate in endocytosis. The structure of the Drosophila Syndapin N-terminal EFC domain reveals a crescent shaped antiparallel dimer with a high affinity for phosphoinositides and a unique membrane-inserting prong upon the concave surface. Combined structural, biochemical and reverse genetic approaches in zebrafish define an important role for Syndapin orthologue, Pacsin3, in the early formation of the notochord during embryonic development. In pacsin3-morphant embryos, midline convergence of notochord precursors is defective as axial mesodermal cells fail to polarize, migrate and differentiate properly. The pacsin3 morphant phenotype of a stunted body axis and contorted trunk is rescued by ectopic expression of Drosophila Syndapin, and depends critically on both the prong that protrudes from the surface of the bowed Syndapin EFC domain and the ability of the antiparallel dimer to bind tightly to phosphoinositides. Our data confirm linkage between directional migration, endocytosis and cell specification during embryonic morphogenesis and highlight a key role for Pacsin3 in this coupling in the notochord

    The Deep Water Abundance on Jupiter: New Constraints from Thermochemical Kinetics and Diffusion Modeling

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    We have developed a one-dimensional thermochemical kinetics and diffusion model for Jupiter's atmosphere that accurately describes the transition from the thermochemical regime in the deep troposphere (where chemical equilibrium is established) to the quenched regime in the upper troposphere (where chemical equilibrium is disrupted). The model is used to calculate chemical abundances of tropospheric constituents and to identify important chemical pathways for CO-CH4 interconversion in hydrogen-dominated atmospheres. In particular, the observed mole fraction and chemical behavior of CO is used to indirectly constrain the Jovian water inventory. Our model can reproduce the observed tropospheric CO abundance provided that the water mole fraction lies in the range (0.25-6.0) x 10^-3 in Jupiter's deep troposphere, corresponding to an enrichment of 0.3 to 7.3 times the protosolar abundance (assumed to be H2O/H2 = 9.61 x 10^-4). Our results suggest that Jupiter's oxygen enrichment is roughly similar to that for carbon, nitrogen, and other heavy elements, and we conclude that formation scenarios that require very large (>8 times solar) enrichments in water can be ruled out. We also evaluate and refine the simple time-constant arguments currently used to predict the quenched CO abundance on Jupiter, other giant planets, and brown dwarfs.Comment: 42 pages, 7 figures, 4 tables, with note added in proof. Accepted for publication in Icarus [in press

    Recognizing true H5N1 infections in humans during confirmed outbreaks.

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    INTRODUCTION: The goal of this study was to evaluate whether any characteristics that are evident at presentation for urgent medical attention could be used to differentiate cases of H5N1 in the absence of viral testing. METHODOLOGY: Information about exposure to poultry, clinical signs and symptoms, treatments, and outcomes was abstracted from existing data in the global avian influenza registry (www.avianfluregistry.org) using standardized data collection tools for documented and possible cases of H5N1 infection who presented for medical attention between 2005-2011 during known H5N1 outbreaks in Azerbaijan, Indonesia, Pakistan and Turkey. RESULTS: Demography, exposure to poultry, and presenting symptoms were compared, with only the common symptoms of fever and headache presenting significantly more frequently in confirmed H5N1 cases than in possible cases. Reported exposure to  infected humans was also more common in confirmed cases. In contrast, unexplained respiratory illness, sore throat, excess sputum production, and rhinorrhea were more frequent in possible cases. Overall, oseltamivir treatment showed a survival benefit, with the greatest benefit shown in H5N1 cases who were treated within two days of symptom onset (51% reduction in case fatality). CONCLUSION: Since prompt treatment with antivirals conferred a strong survival benefit for H5N1 cases, presumptive antiviral treatment should be considered for all possible cases presenting during an outbreak of H5N1 as a potentially life-saving measure

    COVID-19 booster vaccination uptake and infection breakthrough amongst health care workers in Wales:A national prospective cohort study

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    Background: From September 2021, Health Care Workers (HCWs) in Wales began receiving a COVID-19 booster vaccination. This is the first dose beyond the primary vaccination schedule. Given the emergence of new variants, vaccine waning vaccine, and increasing vaccination hesitancy, there is a need to understand booster vaccine uptake and subsequent breakthrough in this high-risk population. Methods: We conducted a prospective, national-scale, observational cohort study of HCWs in Wales using anonymised, linked data from the SAIL Databank. We analysed uptake of COVID-19 booster vaccinations from September 2021 to February 2022, with comparisons against uptake of the initial primary vaccination schedule. We also analysed booster breakthrough, in the form of PCR-confirmed SARS-Cov-2 infection, comparing to the second primary dose. Cox proportional hazard models were used to estimate associations for vaccination uptake and breakthrough regarding staff roles, socio-demographics, household composition, and other factors. Results: We derived a cohort of 73,030 HCWs living in Wales (78% female, 60% 18–49 years old). Uptake was quickest amongst HCWs aged 60 + years old (aHR 2.54, 95%CI 2.45–2.63), compared with those aged 18–29. Asian HCWs had quicker uptake (aHR 1.18, 95%CI 1.14–1.22), whilst Black HCWs had slower uptake (aHR 0.67, 95%CI 0.61–0.74), compared to white HCWs. HCWs residing in the least deprived areas were slightly quicker to have received a booster dose (aHR 1.12, 95%CI 1.09–1.16), compared with those in the most deprived areas. Strongest associations with breakthrough infections were found for those living with children (aHR 1.52, 95%CI 1.41–1.63), compared to two-adult only households. HCWs aged 60 + years old were less likely to get breakthrough infections, compared to those aged 18–29 (aHR 0.42, 95%CI 0.38–0.47). Conclusion: Vaccination uptake was consistently lower among black HCWs, as well as those from deprived areas. Whilst breakthrough infections were highest in households with children
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