840 research outputs found

    A two-step hybrid approach for modeling the nonlinear dynamic response of piezoelectric energy harvesters

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    An effective hybrid computational framework is described here in order to assess the nonlinear dynamic response of piezoelectric energy harvesting devices. The proposed strategy basically consists of two steps. First, fully coupled multiphysics finite element (FE) analyses are performed to evaluate the nonlinear static response of the device. An enhanced reduced-order model is then derived, where the global dynamic response is formulated in the state-space using lumped coefficients enriched with the information derived from the FE simulations. The electromechanical response of piezoelectric beams under forced vibrations is studied by means of the proposed approach, which is also validated by comparing numerical predictions with some experimental results. Such numerical and experimental investigations have been carried out with the main aim of studying the influence of material and geometrical parameters on the global nonlinear response. The advantage of the presented approach is that the overall computational and experimental efforts are significantly reduced while preserving a satisfactory accuracy in the assessment of the global behavior

    Modelling and parameter identiïŹcation of electromechanical systems for energy harvesting and sensing

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    Advanced modelling of electro-mechanical systems for energy harvesting (EH) and sensing is important to develop reliable self-powered autonomous electronic devices and for structural health monitoring (SHM). In this perspective, a novel computational approach is here proposed for both real-time and off-line parameter identification (PI). The system response is governed by a set of four partial differential equations (PDE) where the three displacement components and the electrical potential are the unknowns. Firstly, the finite element (FE) method is used to reduce the PDE problem into a set of ordinary differential equations (ODE). Then, a state- space model is derived with the aim to limit the PI problem to a subset of unknowns. After that, an identification error is introduced and the Lyapunov theory is used to derive the PI algorithm. The numerical implementation is based on a sensitivity analysis feedback block. The overall proposed computational strategy is robust and results in an exponential asymptotic convergence. The accuracy of the PI method is demonstrated by analysing the time–domain response of an array of piezoelectric bimorphs subjected to low–frequency structural random vibrations. The selected case–study is an existing cable–stayed bridge, for which an extensive dynamic monitoring campaign has provided the experimental data. Once time histories of the device response are obtained through time–dependent dynamic FE simulations, the PI algorithm is used to determine the unknown lumped coefficients of the state-space model. The comparison between FE method and lumped parameters model in terms of tip displacement and output voltage demonstrates the superior predictive capability of the new PI algorithm. As a result of the sensitivity analysis, guidelines to assess the optimal array configuration are also provided

    Maml1 acts cooperatively with Gli proteins to regulate Sonic hedgheog signaling pathway

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    Sonic hedgehog (Shh) signaling is essential for proliferation of cerebellar granule cell progenitors (GCPs) and its misregulation is linked to various disorders, including cerebellar cancer medulloblastoma. The effects of Shh pathway are mediated by the Gli family of transcription factors, which controls the expression of a number of target genes, including Gli1. Here, we identify Mastermind-like 1 (Maml1) as a novel regulator of the Shh signaling since it interacts with Gli proteins, working as a potent transcriptional coactivator. Notably, Maml1 silencing results in a significant reduction of Gli target genes expression, with a negative impact on cell growth of NIH3T3 and Patched1−/− mouse embryonic fibroblasts (MEFs), bearing a constitutively active Shh signaling. Remarkably, Shh pathway activity results severely compromised both in MEFs and GCPs deriving from Maml1−/− mice with an impairment of GCPs proliferation and cerebellum development. Therefore Maml1−/− phenotype mimics aspects of Shh pathway deficiency, suggesting an intrinsic requirement for Maml1 in cerebellum development. The present study shows a new role for Maml1 as a component of Shh signaling, which plays a crucial role in both development and tumorigenesis

    Differential Protein Expression Profiles in Glaucomatous Trabecular Meshwork: An Evaluation Study on a Small Primary Open Angle Glaucoma Population

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    INTRODUCTION: Primary open angle glaucoma (POAG) is a progressive optic neuropathy characterized by impaired aqueous outflow and extensive remodeling in the trabecular meshwork (TM). The aim of this study was to characterize and compare the expression patterns of selected proteins belonging to the tissue remodeling, inflammation and growth factor pathways in ex vivo glaucomatous and post-mortem TMs using protein-array analysis. METHODS: TM specimens were collected from 63 white subjects, including 40 patients with glaucoma and 23 controls. Forty POAG TMs were collected at the time of surgery and 23 post-mortem specimens were from non-glaucomatous donor sclerocorneal tissues. Protein profiles were evaluated using a chip-based array consisting of 60 literature-selected antibodies. RESULTS: A different expression of some factors was observed in POAG TMs with respect to post-mortem specimens, either in abundance (interleukin [IL]10, IL6, IL5, IL7, IL12, IL3, macrophage inflammatory protein [MIP]1ÎŽ/α, vascular endothelial growth factor [VEGF], transforming growth factor beta 1 [TGFÎČ1], soluble tumor necrosis factor receptor I [sTNFRI]) or in scarcity (IL16, IL18, intercellular adhesion molecule 3 [ICAM3], matrix metalloproteinase-7 [MMP7], tissue inhibitor of metalloproteinase 1 [TIMP1]). MMP2, MMP7, TGFÎČ1, and VEGF expressions were confirmed by Western blot, zymography, and polymerase chain reaction. No difference in protein profile expression was detected between glaucomatous subtypes. CONCLUSION: The analysis of this small TM population highlighted some proteins linked to POAG, some previously reported and others of new detection (IL7, MIPs, sTNFαRI). A larger POAG population is required to select promising disease-associated biomarker candidates. FUNDING: This study was partially supported by the Fondazione Roma, the Italian Ministry of Health and the “National 5xMille 2010 tax donation to IRCCS-G.B. Bietti Foundation”. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12325-016-0285-x) contains supplementary material, which is available to authorized users

    Digitalization and real-time control to mitigate environmental impacts along rivers: Focus on artificial barriers, hydropower systems and European priorities

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    Hydropower globally represents the main source of renewable energy, and provides several benefits, e.g., water storage and flexibility; on the other hand, it may cause significant impacts on the environment. Hence sustainable hydropower needs to achieve a balance between electricity generation, impacts on ecosystems and benefits on society, supporting the achievement of the Green Deal targets. The implementation of digital, information, communication and control (DICC) technologies is emerging as an effective strategy to support such a trade-off, especially in the European Union (EU), fostering both the green and the digital transitions. In this study, we show how DICC can foster the environmental integration of hydropower into the Earth spheres, with focus on the hydrosphere (e.g., on water quality and quantity, hydropeaking mitigation, environmental flow control), biosphere (e.g., improvement of riparian vegetation, fish habitat and migration), atmosphere (reduction of methane emissions and evaporation from reservoirs), lithosphere (better sediment management, reduction of seepages), and on the anthroposphere (e.g., reduction of pollution associated to combined sewer overflows, chemicals, plastics and microplastics). With reference to the abovementioned Earth spheres, the main DICC applications, case studies, challenges, Technology Readiness Level (TRL), benefits and limitations, and transversal benefits for energy generation and predictive Operation and Maintenance (O&M), are discussed. The priorities for the European Union are highlighted. Although the paper focuses primarly on hydropower, analogous considerations are valid for any artificial barrier, water reservoir and civil structure which interferes with freshwater systems.Digitalization and real-time control to mitigate environmental impacts along rivers: Focus on artificial barriers, hydropower systems and European prioritiespublishedVersio

    Notch3/Jagged1 Circuitry Reinforces Notch Signaling and Sustains T-ALL

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    AbstractDeregulated Notch signaling has been extensively linked to T-cell acute lymphoblastic leukemia (T-ALL). Here, we show a direct relationship between Notch3 receptor and Jagged1 ligand in human cell lines and in a mouse model of T-ALL. We provide evidence that Notch-specific ligand Jagged1 is a new Notch3 signaling target gene. This essential event justifies an aberrant Notch3/Jagged1 cis-expression inside the same cell. Moreover, we demonstrate in Notch3-IC–overexpressing T lymphoma cells that Jagged1 undergoes a raft-associated constitutive processing. The proteolytic cleavage allows the Jagged1 intracellular domain to empower Notch signaling activity and to increase the transcriptional activation of Jagged1 itself (autocrine effect). On the other hand, the release of the soluble Jagged1 extracellular domain has a positive impact on activating Notch signaling in adjacent cells (paracrine effect), finally giving rise to a Notch3/Jagged1 auto-sustaining loop that supports the survival, proliferation, and invasion of lymphoma cells and contributes to the development and progression of Notch-dependent T-ALL. These observations are also supported by a study conducted on a cohort of patients in which Jagged1 expression is associated to adverse prognosis

    Role of interferon lambda 4 and ALT levels in optimising treatment of HCV for patients with low-stage fibrosis

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    The use of new anti-HCV drugs is currently limited by high costs and dual therapy; pegylated interferon and ribavirin (peg-IFN+RBV) still represents the only affordable treatment in patients with low-stage fibrosis. We evaluated the role of Interferon lambda4 (IFNL4) polymorphisms and its combination with on-treatment alanine transaminase (ALT) modification in predicting sustained virological response (SVR) in HCV genotype 1 and 4 patients with low-stage fibrosis. We retrospectively analysed 124 patients with Metavir ≀F2, who received dual therapy at our centre. Genotyping for IFNL4 polymorphisms was assessed at baseline, as well as ALT levels (baseline and week 2, 4, 12 and 24 of therapy). Thirty patients (24%) were TT/TT, 74 (60%) TT/DG and 20 (16%) DG/DG. The SVR rate was significantly higher in TT/TT genotype compare to TT/DG and DG/DG (97% vs. 53% and 50%, respectively, p=0.001). Patients that achieved a 60% reduction of ALT baseline value after 4 weeks of therapy had a significantly higher SVR rate (94% vs. 52%, p<0.001). Factors significantly associated with SVR were TT/TT genotype (p=0.029), RVR (p=0.019) and 60% ALT reduction at 4 week of therapy (p=0.005). The absence of both TT/TT genotype and 60% ALT reduction were negative predictors of SVR (p<0.001). In conclusion, the combined use of IFNL4 polymorphisms and ALT reduction at 4 week of treatment is able to optimize candidates’ selection for peg-IFN+RBV, discriminating those that could still benefit from dual therapy from the ones that need the new regimen

    Why Amphibians Are More Sensitive than Mammals to Xenobiotics

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    Dramatic declines in amphibian populations have been described all over the world since the 1980s. The evidence that the sensitivity to environmental threats is greater in amphibians than in mammals has been generally linked to the observation that amphibians are characterized by a rather permeable skin. Nevertheless, a numerical comparison of data of percutaneous (through the skin) passage between amphibians and mammals is lacking. Therefore, in this investigation we have measured the percutaneous passage of two test molecules (mannitol and antipyrine) and three heavily used herbicides (atrazine, paraquat and glyphosate) in the skin of the frog Rana esculenta (amphibians) and of the pig ear (mammals), by using the same experimental protocol and a simple apparatus which minimizes the edge effect, occurring when the tissue is clamped in the usually used experimental device

    Body piercing and tattoos: a survey on young adults' knowledge of the risks and practices in body art

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    <p>Abstract</p> <p>Background</p> <p>The practice of tattooing and piercing has expanded in western society. In order to verify young adults' knowledge of the risk and practices related to body art, an investigation was conducted among freshmen of the University of Bari in the region of Apulia, Italy.</p> <p>Methods</p> <p>The study was carried out in the Academic Year 2009-2010 through an anonymous self-administered written questionnaire distributed to 1.656 freshmen enrolled in 17 Degree Courses.</p> <p>Results</p> <p>Of the 1.598 students included in the analysis, 78.3% believe it is risky to undergo piercing/tattoo practices. AIDS was indicated as a possible infection by 60.3% of freshmen, hepatitis C by 38.2%, tetanus by 34.3% and hepatitis B by 33.7% of the sample. 28.1% of freshmen were not aware that there are also non-infectious complications. 29% of the sample had at least one piercing or tattoo (this percentage does not include earlobe piercing in women). Of those with body art, the decision to undergo body art was made autonomously in 57.9% of the participants. 56.3% of freshmen undergoing body art had taken less than a month to decide. With regard to the reasons that led the sample to undergo body art, 28.4% were unable to explain it, 23.8% answered to improve their aesthetic aspect, 18.4% to distinguish themselves from others, 12.3% for fashion; 17.1% for other reasons. 25.4% of the sample declared that they had a piercing (79.8% female vs 20.2% male; ratio M/F 1:4.0). The average age for a first piercing was 15.3 years (range 10-27; SD ± 2.9). 9.6% of the sample declared that they have a tattoo (69.9% female vs 30.1% male; ratio M/F 1:2.3). The average age for a first tattoo was 17.5 years (range 10-26, SD ± 2.4).</p> <p>Conclusions</p> <p>Most of the freshmen knew about AIDS-related risks but not other potential risks. Body art is fairly common among young adults (especially women). The decision is often not shared with the family and is undertaken mostly without a specific reason or for the improvement of aesthetic aspect. Information about freshmen's knowledge, attitudes and practices could help in effective planning of health promotion strategies.</p

    Assessing the energy potential of modernizing the European hydropower fleet

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    About 50% of all hydropower plants (HPPs) worldwide were originally commissioned more than 40 years ago, so that the advanced age of the fleet is a major concern across all continents, and especially in Europe. The retrofitting of HPPs can generate several benefits for production, flexibility, safety, management and environment. In this work, the benefits related to energy and flexibility were considered and quantified by conducting a large-scale assessment for the European Union and Europe, taking into account several retrofitting strategies: dam heightening, head loss reduction in waterways, increase of installed power in run-of-the-river and storage power plants, increase of annual inflow, increase of maximum efficiency and weighted efficiency of electro-mechanical equipment, start and stop improvement, digitalization and inflow forecast, floating photovoltaic and reservoir interconnection. For most of these strategies, an indicator of the additional capacity and/or annual production that could be obtained compared to the current conditions was calculated. Excluding site-specific strategies (e.g. installation of new parallel waterways, increase of withdrawals from existing intakes) the resulting compound value of the indicator is 10.2% for European Union and 12.2% for the whole Europe, plus 4-28.6 TWh achievable by interconnecting reservoirs. This suggests that the retrofitting of HPPs can generate significant benefits in terms of energy and flexibility, minimizing environmental impacts, and should be considered as an important element of both energy transition and water management policies
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