319 research outputs found

    A Linear Model of Magnetostrictive Actuators for Active Vibration Control

    Get PDF
    If there is one actuator technology that is almost exclusively linked to a single application, that is the magnetostrictive actuator, the application is active structural vibration control (AVC). Almost all the applications described in the literature on magnetostrictive actuators are related in one way or another to vibration suppression mechanisms. Magnetostrictive actuators (MA) deliver high-output forces and relatively high displacements (compared to other emerging actuator technologies) and can be driven at high frequencies. These characteristics make them suitable for a variety of vibration control applications. The use of this technology, however, requires an accurate knowledge of the dynamics of such actuators. The paper introduces a linear model of magnetostrictive actuators hold in a range of frequencies below 2 kHz useful in real time application as AVC. The hypotesis supporting the linearity of the systems are discussed and the theoretical model is presented. Finally the model is validated by testing two different models of magnetostrictive actuators and comparing experimental results with the theoretical ones

    Flooding Time in Opportunistic Networks under Power Law and Exponential Inter-Contact Times

    Full text link
    Performance bounds for opportunistic networks have been derived in a number of recent papers for several key quantities, such as the expected delivery time of a unicast message, or the flooding time (a measure of how fast information spreads). However, to the best of our knowledge, none of the existing results is derived under a mobility model which is able to reproduce the power law+exponential tail dichotomy of the pairwise node inter-contact time distribution which has been observed in traces of several real opportunistic networks. The contributions of this paper are two-fold: first, we present a simple pairwise contact model -- called the Home-MEG model -- for opportunistic networks based on the observation made in previous work that pairs of nodes in the network tend to meet in very few, selected locations (home locations); this contact model is shown to be able to faithfully reproduce the power law+exponential tail dichotomy of inter-contact time. Second, we use the Home-MEG model to analyze flooding time in opportunistic networks, presenting asymptotic bounds on flooding time that assume different initial conditions for the existence of opportunistic links. Finally, our bounds provide some analytical evidences that the speed of information spreading in opportunistic networks can be much faster than that predicted by simple geometric mobility models

    Familly with two different cases of post- and pre-natal L1 syndrome; When hydrocephaly become "multidisciplinary headache"

    Get PDF
    open11openBukvic, Nenad; Boaretto, Francesca; Loverro, Giuseppe; Susca, Francesco C.; Lovaglio, Rosaura; Patruno, Margherita; Bukvic, Dragoslav; Starcevic, Srdjan; Vazza, Giovanni; Mostaciuollo, Maria Luisa; Resta, NicolettaBukvic, Nenad; Boaretto, Francesca; Loverro, Giuseppe; Susca, Francesco C.; Lovaglio, Rosaura; Patruno, Margherita; Bukvic, Dragoslav; Starcevic, Srdjan; Vazza, Giovanni; Mostaciuollo, Maria Luisa; Resta, Nicolett

    ESDA2010-24888 POWER HARVESTING THROUGH MAGNETOSTRICTIVE DEVICES: A LINEAR MODEL

    Get PDF
    ABSTRACT Energy harvesting, sometimes referred to as "power scavenging" or "energy extraction", can be defined as "converting ambient energies such as vibration,temperature, light, RF energy, etc. t

    Atrial flutter regression in HIV-associated pulmonary arterial hypertension after treatment with bosentan

    Get PDF
    Pulmonary arterial hypertension (PAH) is a rare condition characterized by an increase in pulmonary arterial resistance leading to right heart failure and death. Arrhythmias are a growing problem in PAH; therefore, maintenance of sinus rhythm is considered to be an important treatment aim in these patients. We described the case of a 46-year-old woman with HIV-associated pulmonary arterial hypertension who developed atrial flutter. After treatment with bosentan, it was observed a significant improvement in clinical and haemodynamic parameters. In addition, the AFL, which had previously persisted to both antiarrhythmic drug therapy and electrical stimulation, and had recurred after transthoracic electrical cardioversion, disappeared in absence of any antiarrhythmic drug. Though the precise factors responsible for supraventricular arrhythmogenesis are still largely obscure, it is likely that initiation and maintenance of AFL may depend on all the conditions that can lead to increase in right atrial pressure, size, and wall stress, such as PAH. In our case, bosentan reduced both mean pulmonary artery pressure (mPAP) value and right heart chambers pressures. Therefore, it is conceivable that with the anatomical substrate needed for the maintenance of AFL being disappeared, sinus rhythm was restored.</p

    A Unique Case of Bilateral Thalamic High-Grade Glioma in a Pediatric Patient with LI-Fraumeni Syndrome: Case Presentation and Review of the Literature

    Get PDF
    Li-Fraumeni syndrome (LFS) is a rare high-penetrance and autosomal-dominant pathological condition caused by the germline mutation of the TP53 gene, predisposing to the development of tumors from pediatric age. We conducted a qualitative systematic review following the ENTREQ (Enhancing Transparency in Reporting the Synthesis of Qualitative Research) framework. A search was made in MEDLINE/Pubmed and MeSH Database using the terms “Li-Fraumeni” AND “pediatric high-grade glioma (HGG)”, identifying six cases of HGGs in pediatric patients with LFS. We added a further case with peculiar features such as no familiar history of LFS, association of embryonal rhabdomyosarcoma and bithalamic HGG, whose immunohistochemical profile was accurately defined by Next Generation Sequencing. Knowledge synthesis and case analysis grounded the discussion about challenges in the management of this pathology in pediatric age

    Apolipoprotein C-II deficiency: detection of immunoreactive apolipoprotein C-II in the intestinal mucosa of two patients

    Get PDF
    Recent data suggest that mutant immunoreactive forms of apolipoprotein C-II (apoC-II) can be detected in the plasma of patients with the apoC-II deficiency syndrome. We studied the possible presence of apoC-II mutants in the plasma of two patients with apoC-II deficiency by immunological means. The patients were hypertriglyceridemic, and apoC-II was undetectable in plasma as determined by radial immunodiffusion, electroimmunoassay, and immunonephelometry. Furthermore, apoC-II was undetectable either by electrophoresis or by immunoblotting in the plasma of the probands, while apoC-II was present in the plasma of their parents, although at less than half-normal concentration. Immunochemical localization of apoC-II, however, showed that the apoprotein could be detected within the enterocytes obtained from the intestinal mucosa of the patients. From these data we conclude that the patients synthesize apoC-II, at least in the intestine

    Parallelism of DOG1 expression with recurrence risk in gastrointestinal stromal tumors bearing KIT or PDGFRA mutations

    Get PDF
    BACKGROUND: Gastrointestinal stromal tumors (GISTs) are characterized by mutations of KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) or PDGFRA (platelet-derived growth factor receptor α) that may be efficiently targeted by tyrosine kinase inhibitors (TKI). Notwithstanding the early responsiveness to TKI, the majority of GISTs progress, imposing the need for alternative therapeutic strategies. DOG1 (discovered on GIST-1) shows a higher sensitivity as a diagnostic marker than KIT, however its prognostic role has been little investigated. METHODS: We evaluated DOG1 expression by immunohistochemistry (IHC) in 59 patients with GISTs, and correlated its levels with clinical and pathological features as well as mutational status. Kaplan-Meier analysis was also applied to assess correlations of the staining score with patient recurrence-free survival (RFS). RESULTS: DOG1 was expressed in 66 % of CD117(+) GISTs and highly associated with tumor size and the rate of wild-type tumors. Kaplan-Meier survival analysis showed that a strong DOG1 expression demonstrated by IHC correlated with a worse 2-year RFS rate, suggesting its potential ability to predict GISTs with poor prognosis. CONCLUSIONS: These findings suggest a prognostic role for DOG1, as well as its potential for inclusion in the criteria for risk stratification
    • …
    corecore