An important issue in resonant vibration energy harvesters is that the best performance of the device is limited to a very narrow bandwidth around the fundamental resonance frequency. If the ...excitation frequency deviates slightly from the resonance condition, the power out is drastically reduced. In order to overcome this issue of the conventional resonant cantilever configuration, a non-resonant piezomagnetoelastic energy harvester has been introduced by the authors. This paper presents theoretical and experimental investigations of high-energy orbits in the piezomagnetoelastic energy harvester over a range of excitation frequencies. Lumped-parameter nonlinear equations (electromechanical form of the bistable Duffing oscillator with piezoelectric coupling) can successfully describe the large-amplitude broadband voltage response of the piezomagnetoelastic configuration. Following the comparison of the electromechanical trajectories obtained from the theory, it is experimentally verified that the piezomagnetoelastic configuration can generate an order of magnitude larger power compared to the commonly employed piezoelastic counterpart at several frequencies. Chaotic response of the piezomagnetoelastic configuration is also compared against the periodic response of the piezoelastic configuration theoretically and experimentally. Overcoming the bias caused by the gravity in vertical excitation of the piezomagnetoelastic energy harvester is discussed and utilization of high-energy orbits in the bistable structural configuration for electrostatic, electromagnetic and magnetostrictive transduction mechanisms is summarized.
This well structured volume discusses basic principles for the design and fabrication of bulk and MEMS-based vibration energy systems, the rules required for fabrication of efficient electronics, and ...recent findings in thermoelectric energy harvesting systems.
Cantilevered beams with piezoceramic (PZT) layers are the most commonly investigated type of vibration energy harvesters. A frequently used modeling approach is the single-degree-of-freedom (SDOF) ...modeling of the harvester beam as it allows simple expressions for the electrical outputs. In the literature, since the base excitation on the harvester beam is assumed to be harmonic, the well known SDOF relation is employed for mathematical modeling. In this study, it is shown that the commonly accepted SDOF harmonic base excitation relation may yield highly inaccurate results for predicting the motion of cantilevered beams and bars. First, the response of a cantilevered Euler—Bernoulli beam to general base excitation given in terms of translation and small rotation is reviewed where more sophisticated damping models are considered. Then, the error in the SDOF model is shown and correction factors are derived for improving the SDOF harmonic base excitation model both for transverse and longitudinal vibrations. The formal way of treating the components of mechanical damping is also discussed. After deriving simple expressions for the electrical outputs of the PZT in open-circuit conditions, relevance of the electrical outputs to vibration mode shapes and the electrode locations is investigated and the issue of strain nodes is addressed.
This first update of the ASAS/EULAR recommendations on the management of ankylosing spondylitis (AS) is based on the original paper, a systematic review of existing recommendations and the literature ...since 2005 and the discussion and agreement among 21 international experts, 2 patients and 2 physiotherapists in a meeting in February 2010. Each original bullet point was discussed in detail and reworded if necessary. Decisions on new recommendations were made - if necessary after voting. The strength of the recommendations (SOR) was scored on an 11-point numerical rating scale after the meeting by email. These recommendations apply to patients of all ages that fulfill the modified NY criteria for AS, independent of extra-articular manifestations, and they take into account all drug and non-drug interventions related to AS. Four overarching principles were introduced, implying that one bullet has been moved to this section. There are now 11 bullet points including 2 new ones, one related to extra-articular manifestations and one to changes in the disease course. With a mean score of 9.1 (range 8-10) the SOR was generally very good.
Mammographically dense breast tissue is one of the greatest risk factors for developing breast carcinoma, yet the associated molecular mechanisms remain largely unknown. Importantly, regions of high ...breast density are associated with increased stromal collagen and epithelial cell content. We set out to determine whether increased collagen-matrix density, in the absence of stromal cells, was sufficient to promote proliferation and invasion characteristic of a malignant phenotype in non-transformed mammary epithelial cells. We demonstrate that increased collagen-matrix density increases matrix stiffness to promote an invasive phenotype. High matrix stiffness resulted in increased formation of activated three-dimensional (3D)-matrix adhesions and a chronically elevated outside-in/inside-out focal adhesion (FA) kinase (FAK)-Rho signaling loop, which was necessary to generate and maintain the invasive phenotype. Moreover, this signaling network resulted in hyperactivation of the Ras-mitogen-activated protein kinase (MAPK) pathway, which promoted growth of mammary epithelial cells in vitro and in vivo and activated a clinically relevant proliferation signature that predicts patient outcome. Hence, the current data provide compelling evidence for the importance of the mechanical features of the microenvironment, and suggest that mechanotransduction in these cells occurs through a FAK-Rho-ERK signaling network with extracellular signal-regulated kinase (ERK) as a bottleneck through which much of the response to mechanical stimuli is regulated. As such, we propose that increased matrix stiffness explains part of the mechanism behind increased epithelial proliferation and cancer risk in human patients with high breast tissue density.
To update and integrate the recommendations for ankylosing spondylitis and the recommendations for the use of tumour necrosis factor inhibitors (TNFi) in axial spondyloarthritis (axSpA) into one set ...applicable to the full spectrum of patients with axSpA. Following the latest version of the European League Against Rheumatism (EULAR) Standardised Operating Procedures, two systematic literature reviews first collected the evidence regarding all treatment options (pharmacological and non-pharmacological) that were published since 2009. After a discussion of the results in the steering group and presentation to the task force, overarching principles and recommendations were formulated, and consensus was obtained by informal voting. A total of 5 overarching principles and 13 recommendations were agreed on. The first three recommendations deal with personalised medicine including treatment target and monitoring. Recommendation 4 covers non-pharmacological management. Recommendation 5 describes the central role of non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice drug treatment. Recommendations 6-8 define the rather modest role of analgesics, and disprove glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for axSpA patents with predominant axial involvement. Recommendation 9 refers to biological DMARDs (bDMARDs) including TNFi and IL-17 inhibitors (IL-17i) for patients with high disease activity despite the use (or intolerance/contraindication) of at least two NSAIDs. In addition, they should either have an elevated C reactive protein and/or definite inflammation on MRI and/or radiographic evidence of sacroiliitis. Current practice is to start with a TNFi. Switching to another TNFi or an IL-17i is recommended in case TNFi fails (recommendation 10). Tapering, but not stopping a bDMARD, can be considered in patients in sustained remission (recommendation 11). The final two recommendations (12, 13) deal with surgery and spinal fractures. The 2016 Assessment of SpondyloArthritis international Society-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.
Axial spondyloarthritis (axSpA) is a chronic inflammatory joint disease with a predilection for the spine. It affects young adults and has the potential to have a major impact on quality of life, not ...only because of the chronic pain and fatigue, but also because of the potential for marked disability related to spinal ankylosis. Early detection of axSpA remains a major challenge, for which there is a heightened sense of urgency since it has been shown that earlier intervention with biologics can alter the progression of radiographic change in the spine. Advances in the genetics of axSpA have highlighted a number of candidate genes conferring susceptibility to the disease, but there is evidence of environmental factors playing a role as well. Recently studies in both clinical and experimental axSpA have implicated alterations in the gut microbiome as playing a key role, and the immunology of the gut-joint axis is becoming better understood. The unmet needs which are shaping the research agenda include improvement in early case identification, sensitive and specific biomarkers which could accurately reflect disease activity and severity, improved understanding of the common pathways of inflammation in the skin, eye and gut in axSpA, and novel therapeutic targets which could have curative potential. (J Rheum Dis 2021;28:55-59)
Background Cigarette smoke–induced chronic obstructive pulmonary disease (COPD) is a life-threatening inflammatory disorder of the lung. The development of effective therapies for COPD has been ...hampered by the lack of an animal model that mimics the human disease in a short timeframe. Objectives We sought to create an early-onset mouse model of cigarette smoke–induced COPD that develops the hallmark features of the human condition in a short time-frame. We also sought to use this model to better understand pathogenesis and the roles of macrophages and mast cells (MCs) in patients with COPD. Methods Tightly controlled amounts of cigarette smoke were delivered to the airways of mice, and the development of the pathologic features of COPD was assessed. The roles of macrophages and MC tryptase in pathogenesis were evaluated by using depletion and in vitro studies and MC protease 6–deficient mice. Results After just 8 weeks of smoke exposure, wild-type mice had chronic inflammation, mucus hypersecretion, airway remodeling, emphysema, and reduced lung function. These characteristic features of COPD were glucocorticoid resistant and did not spontaneously resolve. Systemic effects on skeletal muscle and the heart and increased susceptibility to respiratory tract infections also were observed. Macrophages and tryptase-expressing MCs were required for the development of COPD. Recombinant MC tryptase induced proinflammatory responses from cultured macrophages. Conclusion A short-term mouse model of cigarette smoke–induced COPD was developed in which the characteristic features of the disease were induced more rapidly than in existing models. The model can be used to better understand COPD pathogenesis, and we show a requirement for macrophages and tryptase-expressing MCs.
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