51 research outputs found
A Multistate Friction Model for the Compensation of the Asymmetric Hysteresis in the Mechanical Response of Pneumatic Artificial Muscles
These days, biomimetic and compliant actuators have been made available to the main
applications of rehabilitation and assistive robotics. In this context, the interaction control of soft
robots, mechatronic surgical instruments and robotic prostheses can be improved through the
adoption of pneumatic artificial muscles (PAMs), a class of compliant actuators that exhibit some
similarities with the structure and function of biological muscles. Together with the advantage
of implementing adaptive compliance control laws, the nonlinear and hysteretic force/length
characteristics of PAMs pose some challenges in the design and implementation of tracking control
strategies. This paper presents a parsimonious and accurate model of the asymmetric hysteresis
observed in the force response of PAMs. The model has been validated through the experimental
identification of the mechanical response of a small-sized PAM where the asymmetric effects of
hysteresis are more evident. Both the experimental results and a comparison with other dynamic
friction models show that the proposed model could be useful to implement efficient compensation
strategies for the tracking control of soft robots
Complete determination of neutron yield from 62 MeV protons on 9Be for the design of a low â power ADS
Within the European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics of future fast neutron-based reactors are very important. In this respect, an Accelerator Driven System low-power prototype, based on a 70 MeV proton beam impinging on a thick Beryllium converter, was recently proposed and designed within the INFN-E project. The world data on neutron yield from Be target are scarce in this proton energy range. This lack of data calls for a dedicated measurement which was performed at INFN Laboratori Nazionali del Sud, covering a wide angular range, from 0 to 150 degrees, and an almost complete neutron energy interval, from thermal up to the beam energy. In this contribution the results are discussed together with the description of the proposed ADS facility
Progressive skin fibrosis is associated with a decline in lung function and worse survival in patients with diffuse cutaneous systemic sclerosis in the European Scleroderma Trials and Research (EUSTAR) cohort.
Objectives To determine whether progressive skin fibrosis is associated with visceral organ progression and mortality during follow-up in patients with diffuse cutaneous systemic sclerosis (dcSSc). Methods We evaluated patients from the European Scleroderma Trials and Research database with dcSSc, baseline modified Rodnan skin score (mRSS) â„7, valid mRSS at 12±3 months after baseline and â„1 annual follow-up visit. Progressive skin fibrosis was defined as an increase in mRSS >5 and â„25% from baseline to 12±3 months. Outcomes were pulmonary, cardiovascular and renal progression, and all-cause death. Associations between skin progression and outcomes were evaluated by Kaplan-Meier survival analysis and multivariable Cox regression. Results Of 1021 included patients, 78 (7.6%) had progressive skin fibrosis (skin progressors). Median follow-up was 3.4 years. Survival analyses indicated that skin progressors had a significantly higher probability of FVC decline â„10% (53.6% vs 34.4%; p<0.001) and all-cause death (15.4% vs 7.3%; p=0.003) than non-progressors. These significant associations were also found in subgroup analyses of patients with either low baseline mRSS (â€22/51) or short disease duration (â€15 months). In multivariable analyses, skin progression within 1 year was independently associated with FVC decline â„10% (HR 1.79, 95% CI 1.20 to 2.65) and all-cause death (HR 2.58, 95% CI 1.31 to 5.09). Conclusions Progressive skin fibrosis within 1 year is associated with decline in lung function and worse survival in dcSSc during follow-up. These results confirm mRSS as a surrogate marker in dcSSc, which will be helpful for cohort enrichment in future trials and risk stratification in clinical practice
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28â2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65â3·22], p\textless0·0001), American Society of Anesthesiologists grades 3â5 versus grades 1â2 (2·35 [1·57â3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01â2·39], p=0·046), emergency versus elective surgery (1·67 [1·06â2·63], p=0·026), and major versus minor surgery (1·52 [1·01â2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
Study of an intrinsically safe infrastructure for training and research on nuclear technologies
Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will illustrate the conceptual design of an Accelerator-Driven System with high safety standards, but ample flexibility for measurements. The design assumes as base option a 70MeV, 0.75mA proton cyclotron, as the one which will be installed at the INFN National Laboratory in Legnaro, Italy and a Beryllium target, with Helium gas as core coolant.
Safety is guaranteed by limiting the thermal power to 200 kW, with a neutron multiplication coefficient around 0.94, loading the core with fuel containing Uranium enriched at 20% inserted in a solid-lead diffuser. The small decay heat can be passively removed by thermal radiation from the vessel. Such a system could be used to study, among others, some specific aspects of neutron diffusion in lead, beam-core coupling, target cooling and could serve as a training facility
Gestion et formalisation de la connaissance tacite des maĂźtres-artisans de la Calabre
none5Le but de ce projet est de formaliser la connaissance tacite et les savoir-faire opĂ©rationnels des maĂźtres-artisans de la Calabre, une rĂ©gion du sud de lâItalie. Face Ă cette exigence, la MĂ©thodologie d'acquisition des connaissances KADS (Martin, 1994) est apparue la plus adĂ©quate pour assurer lâimplĂ©mentation dâun systĂšme expert, câest-Ă -dire un SystĂšme Ă Base de Connaissances en mesure de reprĂ©senter le processus cognitif des experts dans le secteur artisanal. En synthĂšse, cette activitĂ© de recherche vise Ă crĂ©er un outil de support Ă la dĂ©cision individuelle, capable aussi bien de gĂ©rer et reprĂ©senter la masse complexe des informations liĂ©es au savoir-faire professionnel que de crĂ©er et dĂ©velopper une bibliothĂšque d'actions gĂ©nĂ©riques qui puisse collecter, traiter et diffuser les documents et les informations nĂ©cessaires Ă la modĂ©lisation des connaissances stratĂ©giques et les savoirs du domaine de lâartisanat calabrais.R. Guarasci; E. Cardillo; A. Cosentino; A. Folino; M. TavernitiR., Guarasci; Cardillo, Elena; A., Cosentino; A., Folino; M., Tavernit
Dopaminergic regulation of inflammation and immunity in Parkinson's disease: friend or foe?
Abstract Parkinson's disease (PD) is a neurodegenerative disease affecting 7â10 million people worldwide. Currently, there is no treatment available to prevent or delay PD progression, partially due to the limited understanding of the pathological events which lead to the death of dopaminergic neurons in the substantia nigra in the brain, which is known to be the cause of PD symptoms. The current available treatments aim at compensating dopamine (DA) deficiency in the brain using its precursor levodopa, dopaminergic agonists and some indirect dopaminergic agents. The immune system is emerging as a critical player in PD. Therefore, immuneâbased approaches have recently been proposed to be used as potential antiparkinsonian agents. It has been wellâknown that dopaminergic pathways play a significant role in regulating immune responses in the brain. Although dopaminergic agents are the primary antiparkinsonian treatments, their immune regulatory effect has yet to be fully understood. The present review summarises the current available evidence of the immune regulatory effects of DA and its mimics and discusses dopaminergic agents as antiparkinsonian drugs. Based on the current understanding of their involvement in the regulation of neuroinflammation in PD, we propose that targeting immune pathways involved in PD pathology could offer a better treatment outcome for PD patients
A Biomechatronic Device Actuated by Pneumatic Artificial Muscles for the Automatic Evaluation of Nociceptive Thresholds in Rheumatic Patients
In the current clinical practice, the diagnosis of Rheumatoid Arthritis (RA) draws on
the qualitative evaluation of pain sensitivity thresholds which is affected by several source of
uncertainties, due to an operator-dependent diagnostic protocol. Taking our cue from the diagnostic
shortcomings, we have explored the possibility of automating the measurement of mechanical
nociceptive thresholds through the adoption of soft pneumatic actuators controlled by an embedded
control unit. In this work, we want to show that a purpose-made biomechatronic device actuated
by soft and pneumatic actuators is potentially a boon both for rheumatologists and biomedical
researchers involved in nociception and physicophysical studies. In the full breadth and scope of the
objective diagnosis of RA, the first prototype of a novel biomechatronic device for quantitative and
automatic measurement of mechanical nociceptive thresholds has been designed and tested through
nociception experiments on 10 subjects. The experimental results show that the designed device
can reliably generate the controllable and repeatable nociceptive stimuli needed for the objective
diagnosis of RA
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