Search

Energy harvesting represents one of the recent challenging subjects related to vibration and control. The scale of energy harvesters and storage can involve a wide power range, and the scale of some milliwatt is the elective field of piezoelectric applications. This paper investigates the power frontiers of the piezoelectric-based harvesters applied to automotive units. The analysis, supported by experimental data, aims at estimating the upper bound of the specific power of this technology for powering small devices on board cars. Passive optimally tuned piezoelectric harvester and semi-active controlled ones are compared, based on a new control strategy named VFC-Variational Feedback Control, recently developed by the authors. This new technique makes it possible to increase the total energy storage drained from car vibrations. However, the real advantage for their use relies on a sharp balance between the harvested power and the costs for the additional hardware mass transport. Numerical simulations of circuitry and experimental vibration data provides references to assess the energy convenience in installing this type of devices on board.

Background Infective endocarditis with paravalvular abscess can be complicated by atrioventricular block (AVB), but junctional ectopic tachycardia (JET) has as yet never been described. Case summary A 68-year-old male recently admitted with Staphylococcal aureus endocarditis of his aortic valve bioprosthesis, presented with a regular tachycardia at 240 b.p.m. with a pre-existent right bundle branch block pattern. Haemodynamic collapse necessitated electrical cardioversion, following which high-grade AVB was observed. Multiple recurrences of the same tachycardia required repeated electrical cardioversions and emergent electrophysiological study, which indicated JET. The tachycardia was unresponsive to overdrive pacing, adenosine and intravenous amiodarone, and external cardioversions. Radiofrequency catheter ablation of the atrioventricular node was performed emergently with interruption of the tachycardia. A temporary external pacemaker was implanted via a jugular route. The tachycardia recurred after 48 h at a slower rate, and the patient underwent redo ablation. Transoesophageal echocardiography revealed a pseudoaneurysm of the right sinus of Valsalva probably corresponding to an evacuated abscess. A permanent pacemaker was implanted after active infection had been ruled out. At 3 months of follow-up, the patient had complete AVB, without arrhythmia recurrence. Discussion This is the first case report of JET complicating a paravalvular abscess of the aortic valve with concomitant AVB. Junctional ectopic tachycardia is very rare arrhythmia which is usually seen in children as a congenital arrhythmia or following surgical correction of paediatric heart disease. The differential diagnosis is discussed in detail in the article.

The purpose of the present paper is the identification of optimal trajectories of quadruped robots through genetic algorithms. The method is based on the identification of the optimal time history of forces and torques exchanged between the ground and the body, without any constraints on leg kinematics. The solutions show how it is possible to obtain similar trajectories to those of a horse’s walk but obtaining better performance in terms of energy cost. Finally, a map of the optimal gaits found according to the different speeds is presented, identifying the transition threshold between the walk and the trot as a function of the total energy spent.

Background Loeffler endocarditis is a rare restrictive cardiomyopathy, characterized by hypereosinophilia and fibrous thickening of the endocardium causing progressive onset of heart failure and appearance of thrombi on the walls of the heart chambers. Case summary A 72-year-old man known for hypertension and dyslipidaemia consults for progressive dyspnoea up to New York Heart Association (NYHA) Classes 2–3 over 3 weeks. The biological balance sheet shows a high eosinophil level and an echocardiography shows a mild echodensity fixed to the left apex. After exclusion of a secondary cause of hypereosinophilia, diagnosis of endomyocardial fibrosis in the context of a hypereosinophilic syndrome (HES) is therefore retained. The patient’s clinical presentation with cardiac involvement leads us to start a treatment with corticosteroids. The patient is then regularly followed every 6 months with an initially stable course without complications. Two years later, he develops progressive signs of heart failure. Transthoracic echocardiography shows a left ventricular (LV) dilatation with a normal ejection fraction, but decreased volume due to a large echodense mass in the apex, and moderate aortic regurgitation caused by myocardial infiltration. In view of this rapid evolution, resection of the LV mass with concomitant aortic valve replacement is performed. Pathology confirms eosinophilic infiltration. The clinical course is very good with a patient who remains stable with dyspnoea NYHA Classes 1–2, and echocardiography at 1 year shows a normalization of LV filling pressure. Discussion HES represents a heterogeneous group of disorders characterized by overproduction of eosinophils. One of the major causes of mortality is associated cardiac involvement. Endocardial fibrosis and mural thrombosis are frequent cardiac findings. Echocardiography plays a crucial role in initial diagnosis of endomyocardial fibrosis, and for regular follow-up in order to adapt medical treatment and monitor haemodynamic evolution of the restrictive physiology and of valvular damage caused by the disease’s evolution. This case also shows that surgery can normalize filling pressure and allow a clear improvement on the clinical condition even at the terminal fibrotic state.

This paper is concerned with emergence of novel effects in wave propagation in one-dimensional waveguides, when integrated with periodic nonlocalities. The nonlocalities are introduced by a connectivity superimposed to a conventional waveguide and depicted as a graph with trees and leaves, each with its own periodicity. Merging nonlocality and periodicity notions induces a distinction between homogenous and non-homogenous periodic configurations. Specifically, various unconventional phenomena linked to the presence of nonlocalities result in disruption of the energy transmission in such systems, disclosing new opportunities for vibration isolation applications. To demonstrate these effects, simple models of propagation of plane extension/compression waves in a uniform infinite rod equipped with co-axial spring-like elements is used. The homogenous case is analysed by a direct double, space and time, Fourier transform, leading to discussion of unusual dispersion effects, including vanishing and negative group velocity. In the non-homogeneous case, the canonical Floquet theory is used to identify stopbands and control their positions in the frequency domain. The results are compared with eigenfrequency analysis of unit periodicity cells and finite structures. Next, the forcing problem is considered and the insertion losses in a semi-infinite rod with nonlocal spring effects are computed to corroborate predictions of Floquet theory, providing physical explanations of the obtained results. Finally, possibilities to employ the non-local interaction forces in an active control format to generate stopbands at arbitrarily low frequencies are highlighted.

Background: The Corona Virus Disease (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) requires a rapid solutionand global collaborative efforts in order to define preventive and treatment strategies.Methods: One of the major challenges of this disease is the high number of patients needing advanced respiratory support due to the Acute Respiratory Distress Syndrome (ARDS) as the lung is the major –although not exclusive-target of the virus. The molecular mechanisms, pathogenic drivers and the target cell type(s) in SARSCoV-2 infection are still poorly understood, but the development of a “hyperactive” immune response is proposed to play a role in the evolution of the disease and it is envisioned as a major cause of morbidity and mortality.Results: Here we propose a theory by which the main targets for SARS-CoV-2 are the Type II Alveolar Epithelial Cells and the clinical manifestations of the syndrome are a direct consequence of their involvement. We hypotize the existence of a vicious cycle by which once alveolar damage starts in AEC II cells, the inflammatory state is supported by macrophage proinflammatory polarization (M1), cytokines release and by the activation of the NF-κB pathway.Conclusions: If this theory is confirmed, future therapeutic efforts can be directed to target Type 2 alveolar cells and the molecular pathogenic drivers associated with their dysfunction with currently available therapeutic strategies.

Background: Psoriasis (Ps) is a chronic systemic autoimmune disease associated with pruritus in 64–98% of patients. However, few modestly sized studies assess factors associated with psoriatic pruritus. Objective: To investigate factors associated with Ps pruritus intensity. Methods: Psoriasis patients 18years or older seen in one of 155 centres in Italy between September 2005 and 2009 were identified from the Italian PsoCare registry. Patients without cutaneous psoriasis and those with missed information on pruritus were excluded. Results: We identified 10802 patients, with a mean age 48.8±14.3years. Mild itch was present in 33.2% of patients, moderate in 34.4%, severe in 18.7% and very severe in 13.7%. Higher itch intensity was associated with female gender, lower educational attainment compared to university degree, pustular psoriasis, psoriasis on the head, face, palmoplantar areas, folds and genitalia, more severe disease, disease duration

The present paper investigates a new paradigm to control a swarm of moving individual vehicles, based on the introduction of a few random long-range communications in a queue dominated by short-range car-following dynamics. The theoretical approach adapts the small-world theory, originally proposed in social sciences, to the investigation of these networks. It is shown that the controlled system exhibits properties of higher synchronization and robustness with respect to communication failures. The considered application to a vehicle swarm shows how safety and security of the related traffic dynamics are strongly increased, diminishing the collision probability even in the presence of a hacker attack to some connectivity channels.

Energy harvesting from the environment is an important aspect of many technologies. The scale of energy capturing and storage can involve the power range from mWatt up to MWatt, depending on the used devices and the considered environments (from ambient acoustic and vibration to ocean wave motion, or wind). In this paper, the wind turbine energy harvesting problem is approached as an optimal control problem, where the objective function is the absorption of an amount of energy in a given time interval by a fluid-flow environment, that should be maximized. The interest relies on outlining general control models of fluid-flow-based extraction plants and identifying an optimum strategy for the regulation of an electrical machine to obtain a maximum-efficiency process for the related energy storage. The mathematical tools are found in the light of optimal control theory, where solutions to the fundamental equations are in the frame of Variational Control (the basis of the Pontryagin optimal control theory). A special problem, named Optimally Controlled Betz’s Machine OCBM-optimal control steady wind turbine, is solved in closed form, and it is shown that, in the simpler steady case, it reproduces the maximum efficiency machine developed in Betz’s theory.

Investigating the status of travelling waves in systems integrated with periodic means of distant communication, and the possibility of obstructing the energy flow carried via coupled modes, are of interest. The governing system of linear differential equations with periodic coefficients gives the possibility to adopt Floquet theorem, as a powerful framework, to identify the location of stop band frequencies. The generation of gaps in the band structure of the system owing to the newly launched periodic long-range channels is shown. The likelihood of pulling the first stopband to lower frequency bands as a major demand, is examined by raising some assumptions.

This is a 72 year-old man known for idiopathic HES with endomyocardial fibrosis and moderate aortic regurgitation, treated with corticosteroids and antithrombotics. Two months prior to admission, he develops progressive exertional dyspnea reaching NYHA 3 class, with concomitant peripheral edema and rise in NT-proBNP. Cardiac transthoracic work-up shows a preserved left ventricular ejection fraction, but more marked dilatation with decrease in left ventricular volume due to a large echodense mass in the apex. The transmitral flow is restrictive, and the aortic regurgitation moderate. In view of this rapid evolution, resection of the left ventricular mass with concomitant aortic valve replacement is performed. Pathology confirmed eosinophilic infiltration. First described in 1975, hypereosinophilic syndrome (HES) is a rare pathology that is defined as an absolute eosinophil count (>1,5 G/L) in the peripheral blood with eosinophil-mediated organ damage and /or dysfunction. We know three mains categories; primary (or neoplastic), secondary (or reactive) and idiopathic. Cardiac involvement is uncertain and cardiac injury does not clearly correlate with degree of peripheral eosinophilia. Heart tissue damage evolves through three stages (necrotic, intermediate and fibrotic). Endomyocardial fibrosis and eosinophilic myocarditis, also known as "Loeffler’s endocarditis", are major causes of morbidity and mortality among patients with HES. Echocardiography plays a crucial role in initial diagnosis of endomyocardial fibrosis, displaying myocardial wall thickening, signs of restriction (mitral inflow with large E wave and small A wave; E/A ratio greater than 2, short deceleration time less than 150 ms) and intracardiac thrombus (fixed mass embedding left ventricular apex). Valve regurgitation is another possible complication due to entrapment of the chordae tendinae and/or leaflets during the fibrotic stage of this disease. Cardiac MRI is another important diagnostic tool for precising cardiac involvement. Despite of steadily improving noninvasive diagnostic imaging methods, endomyocardial biosy still remains the gold standard exam and ultrasounds work-up is crucial for follow-up. In conclusion, endomyocardial fibrosis is a rare cause of restrictive cardiomyopathy characterized by echocardiographic sign of elevated filling pressure, progressive endomyocardial thickening, valve regurgitation and possible intracardiac thrombus formation. This case underlines the importance of echocardiography in initial diagnosis and regular follow-up of this type of patients, in order to adapt medical treatment and monitor hemodynamic evolution of the restrictive physiology and of valvular damage. Abstract P703 Figure. HES-3

The obstacle avoidance maneuver is required for an autonomous vehicle. It is essential to define the system's performance by evaluating the minimum reaction times of the vehicle and analyzing the probability of success of the avoiding operation. This paper presents a collision avoidance algorithm based on the velocity obstacle approach that guarantees collision-free maneuvers. The vehicle is controlled by an optimal feedback control named FLOP, designed to produce the best performance in terms of safety and minimum kinetic collision energy. Dimensionless accident evaluation parameters are proposed to compare different crash scenarios.