182 research outputs found
Autonomous Neuro-Fuzzy Solution for Fault Detection and Attitude Control of a 3U Cubesat
In recent years, thanks to the increase of the know-how on machine-learning techniques and the advance of the computational capabilities of on-board processing, algorithms involving artificial intelligence (i.e. neural networks and fuzzy logics) have began to spread even in the space applications. Nowadays, thanks to these reasons, the implementation of such techniques is becoming realizable even on smaller platforms, such as CubeSats.
The paper presents an algorithm for the fault detection and for the fault-tolerant attitude control of a 3U CubeSat, developed in MathWorks Matlab & Simulink environment.
This algorithm involves fuzzy logic and multi-layer feed-forward online-trained neural network (percep- tron).
It is utilized in a simulation of a CubeSat satellite placed in LEO, considering as available attitude con- trol actuators three magnetic torquers and one reaction wheel. In particular, fuzzy logics are used for the fault detection and isolation, while the neural network is employed for adapting the control to the perturbation introduced by the fault. The simulation is performed considering the attitude of the satellite known without measurement error.
In addition, the paper presents the system, simulator and algorithm architecture, with a particular focus on the design of fuzzy logics (connection and implication operators, rules and input/output qualificators) and the neural network architecture (number of layers, neurons per layer), threshold and activation func- tions, offline and online training algorithm and its data management.
With respect to the offline training, a model predictive controller has been adopted as supervisor. In con- clusion the paper presents the control torques, state variables and fuzzy output evolution, in the different faulty configurations.
Results show that the implementation of the fuzzy logics joined with neural networks provide good ro- bustness, stability and adaptibility of the system, allowing to satisfy specified performance requirements even in the event of a malfunctioning of a system actuator
Water-Soluble Gold Nanoparticles Protected by Fluorinated Amphiphilic Thiolates
The preparation and the properties of gold nanoparticles (Au NPs) protected by perfluorinated amphiphiles are described. The thiols were devised to form a perfluorinated region close to the gold surface and to have a hydrophilic portion in contact with the bulk solvent to impart solubility in water. The monolayer protected clusters were prepared, in an homogeneous phase using sodium thiolates because of the low nucleophilicity of the alpha-perfluorinated thiols, and fully characterized with 1H, 19F NMR spectrometry, IR and UV-vis absorption spectroscopies, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Au NPs with core diameters ranging from 1.6 to 2.9 nm, depending on the reaction conditions, were obtained. Water-soluble NPs (MPC-F8-PEGs) were obtained with the thiol HS-F8-PEG ending with a short poly(ethylene glycol) unit (PEG-OMe 550), whereas thiols with shorter PEG chains give rise to NPs insoluble in water. MPC-F8-PEGs undergo an exchange reaction with amphiphilic alkyl thiols. ESR investigations, using a hydrophobic radical probe, indicate that the MPC-F8-PEG monolayer shows a greater hydrophobicity compared to the analogous hydrogenated monolayer.
6D physical interaction with a fully actuated aerial robot
This paper presents the design, control, and experimental validation of a novel fully-actuated aerial robot for physically interactive tasks, named Tilt-Hex. We show how the Tilt-Hex, a tilted-propeller hexarotor is able to control the full pose (position and orientation independently) using a geometric control, and to exert a full-wrench (force and torque independently) with a rigidly attached end-effector using an admittance control paradigm. An outer loop control governs the desired admittance behavior and an inner loop based on geometric control ensures pose tracking. The interaction forces are estimated by a momentum based observer. Control and observation are made possible by a precise control and measurement of the speed of each propeller. An extensive experimental campaign shows that the Tilt-Hex is able to outperform the classical underactuated multi-rotors in terms of stability, accuracy and dexterity and represent one of the best choice at date for tasks requiring aerial physical interaction
Nutrition and Inflammation in Older Individuals: Focus on Vitamin D, n-3 Polyunsaturated Fatty Acids and Whey Proteins
Chronic activation of the inflammatory response, defined as inflammaging, is the key physio-pathological substrate for anabolic resistance, sarcopenia and frailty in older individuals. Nutrients can theoretically modulate this phenomenon. The underlying molecular mechanisms reducing the synthesis of pro-inflammatory mediators have been elucidated, particularly for vitamin D, n-3 polyunsaturated fatty acids (PUFA) and whey proteins. In this paper, we review the current evidence emerging from observational and intervention studies, performed in older individuals, either community-dwelling or hospitalized with acute disease, and evaluating the effects of intake of vitamin D, n-3 PUFA and whey proteins on inflammatory markers, such as C-Reactive Protein (CRP), interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor \u3b1 (TNF-\u3b1). After the analysis, we conclude that there is sufficient evidence for an anti-inflammatory effect in aging only for n-3 PUFA intake, while the few existing intervention studies do not support a similar activity for vitamin D and whey supplements. There is need in the future of large, high-quality studies testing the effects of combined dietary interventions including the above mentioned nutrients on inflammation and health-related outcomes
Stem cell transplantation in neuropathic pain
The neuropathic pain is a disabling condition which occurs secondarily to injury of peripheral or central nervous system. To date, the neuronal basis are poorly understood and effective treatments with long lasting relief are not available. Stem cells represent a more innovative and interesting therapeutic approach for tissue damage restoration. This study evaluates the effect of intravenous administration of murine adult neuronal stem cells and the administration in the lateral cerebral ventricle of human mesenchymal stem cells in two animal models of peripheral mononeuropathy: the chronic constriction injury and the spared nerve injury of the sciatic nerve. Pain related behaviour evaluation, morphofunctional alterations and the stem cell localization in brain, spinal cord and sciatic nerve were studied using respectively behavioural tests and immunohistochemical techniques. Stem cells were able to reduce pain-like behaviours, such as mechanical allodynia and thermal hyperalgesia, and to decrease the activation of nociceptive neurons at central level. The stem cells injected intravenously homed in the injured nerve site, while when injected in the cerebral ventricle was localized near the injection site. These data suggest that the stem cells administered intravenously influence directly the damaged area, whereas the cells injected in the cerebral ventricle could modulate the central neuronal pathway, responsible of neuropathic pain. The administration of stem cells in neuropathic pain syndromes may be a more suitable therapy than ‘’classical’’ drugs to decrease the unpleasant related symptoms
Real-life effectiveness of tildrakizumab in chronic plaque psoriasis: A 52-week multicentre retrospective study—IL PSO (Italian landscape psoriasis)
Background: Tildrakizumab is a humanized monoclonal antibody that binds selectively the p19 subunit of interleukin-23. It is approved for treatment of moderate– severe chronic plaque psoriasis. Objectives: We conducted a 52-week retrospective study to assess the effectiveness and safety of tildrakizumab in a real-life setting. Methods: Our retrospective study included 237 consecutive adults with moderateto-severe plaque psoriasis, enrolled in 10 different Italian centres, treated with tildrakizumab up to Week 52. Patient characteristics, comorbidities, previous treatmentsand the PASI (Psoriasis Area and Severity Index) score at each visit (baseline, Week 16, Week 28 and Week 52) were retrieved from the electronic medical records. The percentages of patients achieving 75%, 90% and 100% (PASI 75, PASI 90 and PASI 100) improvement in PASI with respect to baseline PASI were registered. Results: At Week 52, 90.91%, 73.55% and 58.68% of patients achieved a PASI reduction ≥75% (PASI 75), PASI 90 and PASI 100, respectively. An absolute PASI≤2 was reached by 85.95% at Week 52. Compared with Phase 3 clinical trials, we observed similar rates of PASI 75/90 responses and higher percentages of patients achieving PASI 100. Patients who had not responded to previous biologic treatments and patients with cardio-metabolic comorbidities were significantly more likely to achieve PASI 100 at Week 28 and PASI 90 at Week 52. The higher body mass index did not interfere with the odds of reaching PASI 75/90/100 at each time point. No significant safety findings were recorded throughout the study, and none of the patients had to interrupt the treatment because of adverse events. Conclusion: Our data suggest that the efficacy of tildrakizumab for plaque psoriasis in ‘real-life’ clinical practice is comparable with Phase 3 clinical trials with higher percentages of patients achieving complete skin clearance (PASI 100) at Weeks 16, 28 and 52
Immunogenicity and clinical efficacy of anti-SARS-CoV-2 vaccination in patients with hematological malignancies: results of a prospective cohort study of 365 patients
Effectiveness, Tolerability, and Drug Survival of Risankizumab in a Real-World Setting: A Three-Year Retrospective Multicenter Study—IL PSO (ITALIAN LANDSCAPE PSORIASIS)
Background: Risankizumab is a humanized monoclonal antibody that selectively inhibits interleukin-23. It has been approved for moderate-to-severe plaque psoriasis and has shown efficacy and safety in clinical trials and real-world experiences. This study aimed to evaluate the long-term effectiveness, safety, and drug survival of risankizumab in a real-life setting. Materials and Methods: We included patients treated with risankizumab from January 2019 to February 2023. A Psoriasis Area and Severity Index score (PASI) was collected at weeks 0, 16, 28, 52, 104, and 156, when available. The occurrence of any adverse events was recorded at each visit. Results: We enrolled 1047 patients. At week 52, a ≥90% improvement in PASI was observed in 81.44% of patients, with a continuous improvement throughout the study (88.99% and 99.07% at weeks 104 and 156, respectively). After three years of treatment, all patients involving the scalp, palms/soles, and genitalia and 95% of patients with nail psoriasis achieved a complete or almost complete skin clearance. No significant safety findings were observed, and 90.73% of the patients were still on treatment after 36 months. Conclusions: This study supports the long-term effectiveness and safety of risankizumab in a real- world setting, even in patients involving difficult-to-treat areas
Brodalumab for the treatment of plaque psoriasis in a real-life setting: a 3 years multicenter retrospective study—IL PSO (Italian landscape psoriasis)
Introduction: Brodalumab is a monoclonal antibody that targets the subunit A of the interleukin-17A receptor (IL17RA), inhibiting the signaling of various isoforms of the IL-17 family. It has been approved for the treatment of moderate-to-severe plaque psoriasis after being evaluated in three Phase-3 trials. However, long-term data on brodalumab in a real-life setting are still limited
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