184 research outputs found

    The 3D numerical simulation of near-source ground motion during the Marsica earthquake, central Italy, 100 years later

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    In this paper we show 3D physics-based numerical simulations of ground motion during one of the most devastating earthquakes in the recent Italian history, occurred on Jan 13, 1915, Marsica, Central Italy. The results provide a realistic estimate of the earthquake ground motion and fit reasonably well both the geodetic measurements of permanent ground settlement, and the observed macroseismic distribution of damage. In addition, these results provide a very useful benchmark to improve the current knowledge of near-source earthquake ground motion, including evaluation of the best distance metrics to describe the spatial variability of the peak values of ground motion, the relative importance of fault normal vs fault parallel components, the conditions under which vertical ground motion may prevail, as well as the adequacy of 1D vs 3D modelling of site amplification effects

    Dispersion-dissipation analysis of 3D continuous and discontinuous spectral element methods for the elastodynamics equation

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    In this paper we present a three dimensional dispersion and dissipation analysis for both the semi discrete and the fully discrete approximation of the elastodynamics equation based on the plane wave method. For space discretization we compare different approximation strategies, namely the continuous and the discontinuous spectral element method on both tetrahedral and hexahedral elements. For time discretization we employ a leapfrog time integration scheme. Several numerical results are presented and discussed

    High-order Discontinuous Galerkin methods for the elastodynamics equation on polygonal and polyhedral meshes

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    We propose and analyze a high-order Discontinuous Galerkin Finite Element Method for the approximate solution of wave propagation problems modeled by the elastodynamics equations on computational meshes made by polygonal and polyhedral elements. We analyze the well posedness of the resulting formulation, prove hp-version error a-priori estimates, and present a dispersion analysis, showing that polygonal meshes behave as classical simplicial/quadrilateral grids in terms of dispersion properties. The theoretical estimates are confirmed through various two-dimensional numerical verifications

    Exploring hypotheses of the actions of TGF-beta 1 in epidermal wound healing using a 3D computational multiscale model of the human epidermis

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    In vivo and in vitro studies give a paradoxical picture of the actions of the key regulatory factor TGF-beta 1 in epidermal wound healing with it stimulating migration of keratinocytes but also inhibiting their proliferation. To try to reconcile these into an easily visualized 3D model of wound healing amenable for experimentation by cell biologists, a multiscale model of the formation of a 3D skin epithelium was established with TGF-beta 1 literature-derived rule sets and equations embedded within it. At the cellular level, an agent-based bottom-up model that focuses on individual interacting units ( keratinocytes) was used. This was based on literature-derived rules governing keratinocyte behavior and keratinocyte/ECM interactions. The selection of these rule sets is described in detail in this paper. The agent-based model was then linked with a subcellular model of TGF-beta 1 production and its action on keratinocytes simulated with a complex pathway simulator. This multiscale model can be run at a cellular level only or at a combined cellular/subcellular level. It was then initially challenged ( by wounding) to investigate the behavior of keratinocytes in wound healing at the cellular level. To investigate the possible actions of TGF-beta 1, several hypotheses were then explored by deliberately manipulating some of these rule sets at subcellular levels. This exercise readily eliminated some hypotheses and identified a sequence of spatial-temporal actions of TGF-beta 1 for normal successful wound healing in an easy-to-follow 3D model. We suggest this multiscale model offers a valuable, easy-to-visualize aid to our understanding of the actions of this key regulator in wound healing, and provides a model that can now be used to explore pathologies of wound healing

    Effect of dietary supplementation with ultramicronized palmitoylethanolamide in maintaining remission in cats with nonflea hypersensitivity dermatitis: a double-blind, multicentre, randomized, placebo-controlled study

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    Background Feline nonflea hypersensitivity dermatitis (NFHD) is a frequent cause of over-grooming, scratching and skin lesions. Multimodal therapy often is necessary. Hypothesis/Objectives To investigate the efficacy of ultramicronized palmitoylethanolamide (PEA-um) in maintaining methylprednisolone-induced remission in NFHD cats. Animals Fifty-seven NFHD cats with nonseasonal pruritus were enrolled originally, of which 25 completed all study requirements to be eligible for analysis. Methods and materials Cats were randomly assigned to PEA-um (15 mg/kg per os, once daily; n = 29) or placebo (n = 28) while receiving a 28 day tapering methylprednisolone course. Cats responding favourably to methylprednisolone were then administered only PEA-um (n = 21) or placebo (n = 23) for another eight weeks, followed by a four week long treatment-free period. Cats were maintained in the study until relapse or study end, whichever came first. Primary outcome was time to relapse. Secondary outcomes were pruritus Visual Analog Scale (pVAS), SCORing Feline Allergic Dermatitis scale (SCORFAD) and owner Global Assessment Score (GAS). Results Mean relapse time was 40.5 days (+/- 7.8 SE) in PEA-um treated cats (n = 13) and 22.2 days (+/- 3.7 SE) for placebo (n = 12; P = 0.04). On Day 28, the severity of pruritus was lower in the PEA-um treated cats compared to placebo (P = 0.03). Mean worsening of pruritus at the final study day was lower in the PEA-um group compared to placebo (P = 0.04), whereas SCORFAD was not different between groups. Mean owner GAS at the final study day was better in the PEA-um than the placebo-treated group (P = 0.05). Conclusion and clinical importance Ultramicronized palmitoylethanolamide could represent an effective and safe option to delay relapse in NFHD cats

    Adenoviral gene transfer of angiostatic ATF-BPTI inhibits tumour growth

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    BACKGROUND: The outgrowth of new vessels – angiogenesis – in the tumour mass is considered to be a limiting factor of tumour growth. To inhibit the matrix lysis that is part of the tumour angiogenesis, we employed the chimeric protein mhATF-BPTI, composed of the receptor binding part of the urokinase (ATF) linked to an inhibitor of plasmin (BPTI). METHODS: For delivery, recombinant adenovirus encoding the transgene of interest was injected intravenously or locally into the tumour. The anti tumour effect of this compound was compared to that of human endostatin and of mhATF alone in two different rat bronchial carcinomas growing either as subcutaneous implants or as metastases. RESULTS: Significant inhibition of the tumour growth and decrease of the number of lung metastasis was achieved when the concentration of mhATF-BPTI at the tumour site was above 400 of ng / g tissue. This concentration could be achieved via production by the liver, only if permissive to the recombinant adenovirus. When the tumour cells could be transduced, local delivery of the vector was enough to obtain a response. In the case of metastasis, the capacity of the lung tissue to concentrate the encoded protein was essential to reach the required therapeutic levels. Further, endostatin or mhATF could not reproduce the effects of mhATF-BPTI, at similar concentrations (mhATF) and even at 10-fold higher concentration (endostatin). CONCLUSION: The ATF-BPTI was shown to inhibit tumour growth of different rat lung tumours when critical concentration was reached. In these tumour models, endostatin or ATF induce almost no tumour response
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