IRIS Università degli Studi dell'Aquila
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Research on flexible ultrasonic infrared detection of crack defects in irregular metal components
No full textA novel flexible ultrasonic infrared nondestructive testing approach employing a spherical excitation head was proposed to better meet the detection requirements of metal surfaces with complex geometries. Initially, by integrating Hertzian contact theory and fractal theory, the contact mechanism of the spherical excitation head in ultrasonic dry coupling was systematically analyzed, with a particular focus on the key factors governing interface contact stiffness. Subsequently, simulation studies unveiled the stress field distribution induced by the spherical excitation head, along with the associated thermal effects at crack defects. It was demonstrated that the spherical excitation head could generate a more uniform and stable stress field while amplifying thermal responses in defective regions. Ultimately, based on these insights, a flexible ultrasonic infrared nondestructive testing system equipped with two orthogonal digital lock-in algorithms was developed, and experimental validation was conducted on connecting rod specimens with crack defects. The results substantiate that this method can accurately detect cracks measuring 10.52 mm and 21.24 mm in length
Subcutaneous ICD sports safety registry (SISS registry)
No full textBackground: Exercise has a positive impact on physical function and quality of life. However, individuals with an implantable cardioverter-defibrillator (ICD) may experience adverse events during sports activities. To date, scientific data on the safety of sports participation in patients with subcutaneous ICDs (S-ICDs) are lacking. This study aims to analyze the occurrence of appropriate and inappropriate arrhythmic events related to sports activity in a population of S-ICD patients. Methods: Consecutive patients who underwent S-ICD implantation were enrolled. Baseline clinical data, as well as information on sports activity and arrhythmic events, were collected. Results: Among 280 patients (median age 46 [32-55] years; 72 % male) included in the registry, 205 (73 %) engaged in sports activities. During a follow-up period of 38 ± 13 months, 27 patients (13 %) experienced appropriate shocks. Of these, 20 (74.1 %) occurred at rest and 7 (25.9 %) during peak performance in sports. All patients who received appropriate shocks were implanted for secondary prevention. Additionally, 27 patients (13.1 %) experienced inappropriate shocks, with 15 (55.6 %) occurring at rest and 12 (44.4 %) during peak physical activity, primarily due to T-wave oversensing. No significant differences were observed in type or intensity of sports activity between patients who experienced shocks and those who did not. Conclusion: In S-ICD patients, both appropriate and inappropriate shocks occur more frequently during peak physical performance but are not associated with the type or intensity of sports activity. Appropriate shocks were most common in patients with arrhythmogenic or ischemic cardiomyopathy, while inappropriate shocks were mainly due to T-wave oversensing
Tecniche avanzate di riduzione dell'ordine del modello di modelli PEEC ritardati
No full textThe partial element equivalent circuit (PEEC) method is a widely recognized electromagnetic computational technique due to its ability to represent electromagnetic phenomena using equivalent circuits. It is a popular technique in electromagnetic compatibility (EC) analysis, antenna, and interconnect design. Quasi-static PEEC models are represented by a set of ordinary differential equations (ODEs). However, delayed PEEC models are better suited for accurately capturing the behavior of complex electrically long structures where propagation delays are significant. These delayed PEEC models are formulated using neutral delayed differential equations (NDDEs). Due to the large number of state variables, PEEC models can be computationally intensive.
We present advanced model order reduction (MOR) techniques for PEEC models. This work focuses on the development and application of proper orthogonal decomposition (POD)-based MOR techniques used for delayed PEEC models. We present the traditional and incremental singular value decomposition (SVD) techniques in frequency domain to optimize the reduction. We also modify the snapshot collection by considering the derivatives snapshots in the frequency domain which not only improve the accuracy of the reduced order models (ROMs) but also reduce the computational complexity during the construction of ROMs.
The effectiveness of these approaches is validated through extensive numerical examples in both the frequency and time domain, demonstrating significant improvements in computational efficiency without compromising model accuracy. This research contributes to advancing MOR techniques for EM analysis and extends the applicability of PEEC models to more complex EM-circuit problems
Volatile Fatty Acid Recovery from Simulated Digestate by Stripping
Get PDFVolatile Fatty Acids (VFAs) are essential building block chemicals with a significantly increasing market demand. However, their production is traditionally based on non-renewable petrochemical sources, causing severe adverse health and environmental effects. The recovery of VFAs from organic substrates matches the need to approach a circular economy, which includes resource recovery, reuse and recycling. This work aimed to recover VFAs from simulated digestate by using an innovative and sustainable approach consisting of gas stripping followed by absorption. Gas stripping is based on separating volatile compounds from fermented broth or process streams through its interaction with the water-saturated gas phase. The proposed approach aims to be a breakthrough technology focused on the clean production of raw materials. Experimental investigations were performed on a lab scale to recover VFAs from a water solution by considering a single acid and a mix of acids. Moreover, the process simulation was carried out to validate the stripping step and the thermodynamic model to scale up the technology
NET4SAFE: Network for Emergency and Safety Management. A Platform for Emergency Management and Accessibility
No full textThe constant increase in the frequency and intensity of impactful climate events, combined with the Italian territory’s complex morphology and extreme urban fragmentation, underscores the urgent need for tools that support more resilient and effective planning. This study introduces an innovative and scalable methodology for analyzing territorial accessibility. The model is based on an initial application of network theory, which, through geospatial data, represents urban settlements and their infrastructural connections. The aim is to identify areas most vulnerable due to limited accessibility to both services and key infrastructure networks. The study sets the foundation for the development of an operational tool to support emergency planning and response management. The proposed system serves as an efficient Decision Support System (DSS) for public authorities, adaptable to various territorial scales and integrable with demographic, building, and risk-related indicators. This approach addresses a gap in territorial knowledge and aims to provide an accurate representation of the infrastructural fabric. Such representation enables the definition of intervention priorities and risk mitigation strategies, ultimately promoting sustainable urban development
Studio di modelli in vitro e in vivo di patologia oculare in risposta a stimolo neurotrofico: identificazione di nuovi biomarcatori e bersagli terapeutici
No full textThe retinal pigment epithelium (RPE), a key cell layer in the eye, plays an important role in
retinal health. Dysfunction of the RPE is linked not only to age-related macular degeneration
(AMD) but also to glaucoma, a major cause of blindness. RPE dysfunction contributes to
the degeneration of retinal ganglion cells (RGCs), which is central to glaucoma-related
vision loss. Oxidative stress and inflammation in RPE and Müller cells exacerbate glaucoma,
and dysfunction of RPE can also disrupt the blood-retinal barrier, leading to the
accumulation of toxic substances. Currently, neither biomarkers nor effective therapy are
available for the disease. Nerve growth factor (NGF) has shown potential as a
neuroprotective agent, but mechanisms of action remain unclear. In this study, after
generating a differentiated RPE cell model from ARPE-19, which confirmed the expression
of specific RPE markers (e.g. RPE65, CRALBP, MITF, RDH10), an in vitro model of
glaucoma was set by using an original device able to induce pressure increase (HP) on
cultured cells. The above-mentioned human RPE and rat Müller cells were used for
experimental procedures. Several of the most important proteins involved in oxidative stress
(e.g. DJ-1, NRF2, HO-1, CAT, SOD-1) and inflammatory (IL-6, IL-1beta) responses were
analyzed in HP condition, in the presence or absence of NGF. At the same way, expression
levels of three microRNAs (miR-34a-5p, miR-29c-3p, miR-146a-5p) were evaluated, and a
direct target of miR-34a-5p (SIRT-1) was considered as well. Interestingly, results
highlighted the suitability of the model for the study of glaucoma, evidencing, on one hand,
expected and coherent levels of expression of the considered markers, and, on the other, the
putative role of NGF as neuroprotective factor able to revert conditions caused by HP. Such
effects were evidenced in terms of both oxidative stress/inflammation-related proteins’ and
microRNAs’ expression levels in response to specific experimental conditions.
In conclusion, the study provided interesting results and opens further analyses on preclinical
models to assess the potential use of NGF for glaucoma treatment and validate candidate
miRNAs here described as novel biomarkers/therapeutic targets.
The industrial partner of the project, included in the PhD PON R&I program, was Dompé
S.p.A
Longitudinal assessment of migraine burden in resistant and refractory migraine – Data from the prospective REFINE study
Get PDFBackground: Some individuals with migraine fail to respond adequately to preventive treatments, bearing most of migraine burden. The European Headache Federation (EHF) classifies these individuals into resistant migraine (ResM) or refractory migraine (RefM) according to treatment failures, debilitating headache days, and disease duration. We investigated the evolution of these categories over six months in patients treated at tertiary headache centers and whether they accurately reflect disability and burden. Methods: Participants from the multicenter, prospective REFINE study were classified into three categories of treatment responsiveness, namely RefM, ResM, and non-refractory non-resistant migraine (NRNRM). The primary objective was to determine the trajectories of category changes over six months. Secondary outcomes included changes in the 6-item Headache Impact Test (HIT-6), Headache-Attributed Lost Time (HALT), and Hospital Anxiety and Depression Scale (HADS-A and HADS-D) scores. Results: Overall, 489 participants were included with a median age of 45 years (IQR = 36–53); 389 participants (79.7%) were female; 256 (52.4%) had NRNRM, 178 (36.4%) ResM, and 55 (11.2%) RefM. At follow-up, 200/256 (78.1%) NRNRM remained stable, while 56/256 (21.9%) progressed to ResM. Among those with ResM, 98/178 (55.1%) remained stable, 72/178 (40.5%) improved to NRNRM, and 8/178 (4.5%) worsened to RefM. Among participants with RefM, 37/55 (67.3%) remained stable, while 18/55 (32.7%) improved to NRNRM. Participants with RefM and ResM presented significantly higher scores at baseline than those with NRNRM. Over time, HIT-6, HALT, and HADS-A scores improved substantially in the overall cohort (p < 0.001, p < 0.001, and p = 0.006, respectively). Improvements were observed in participants with ResM across all scores and HIT-6 and HALT for NRNRM, but no improvement was noted in participants with RefM. Conclusions: Over six months, ~ 40% of ResM and ~ 30% of RefM individuals improved to NRNRM, while ~ 20% of NRNRM developed treatment resistance after receiving care in tertiary headache centers. Participants with ResM had a better prognosis than those with RefM. While both ResM and RefM reflect high migraine disability burden, they might present relevant differences in their management and prognosis
Effect of Individualized Whole-Body Vibration Exercise on Locomotion and Postural Control in a Person with Multiple Sclerosis: A 5-Year Case Report
Get PDFThe present study aims to investigate the multi-year effects (5 years) of individualized whole-body vibration (WBV) on locomotion, postural control, and handgrip strength in a 68-year-old man with relapse remitting multiple sclerosis (PwRRMS). The dose–response relationship induced by a single session was quantified by determining the surface electromyographic activity (sEMG) of the participant. The participant wore an orthosis to limit the lack of foot dorsiflexion in the weakest limb during walking in daily life. The gait alteration during walking was assessed at 1, 2 and 3 km/h (without the orthosis) through angle–angle diagrams by quantifying the area, perimeter and shape of the loops, and the sEMG of leg muscles was recorded in both limbs. The evaluation of postural control was conducted during upright standing by quantifying the displacement of the center of pressure (CoP). The handgrip strength was assessed by measuring the force–time profile synchronized with the sEMG activity of upper arm muscles. The participant improved his ability to walk at higher speeds (2–3 km/h) without the orthosis. There were greater improvements in the area and perimeter of angle–angle diagrams for the weakest limb (Δ = 36–51%). The sEMG activity of the shank muscles increased at all speeds, particularly in the tibialis anterior of weakest limbs (Δ = 10–68%). The CoP displacement during upright standing decreased (Δ = 40–60%), whereas the handgrip strength increased (Δ = 32% average). Over the 5-year period of intervention, the individualized WBV improved locomotion, postural control and handgrip strength without side effects. Future studies should consider the possibility of implementing an individualized WBV in PwRRMS
Flow and thermal modelling of the argon volume in the DarkSide-20k TPC
Get PDFThe DarkSide-20k dark matter experiment, currently under construction at LNGS, features a dual-phase time projection chamber (TPC) with a ∼ 50 t argon target from an underground well. At this scale, it is crucial to optimise the argon flow pattern for efficient target purification and for fast distribution of internal gaseous calibration sources with lifetimes of the order of hours. To this end, we have performed computational fluid dynamics simulations and heat transfer calculations. The residence time distribution shows that the detector is well-mixed on time-scales of the turnover time (∼ 40 d). Notably, simulations show that despite a two-order-of-magnitude difference between the turnover time and the half-life of 83mKr of 1.83 h, source atoms have the highest probability to reach the centre of the TPC 13 min after their injection, allowing for a homogeneous distribution before undergoing radioactive decay. We further analyse the thermal aspects of dual-phase operation and define the requirements for the formation of a stable gas pocket on top of the liquid. We find a best-estimate value for the heat transfer rate at the liquid-gas interface of 62 W with an upper limit of 144 W and a minimum gas pocket inlet temperature of 89 K to avoid condensation on the acrylic anode. This study also informs the placement of liquid inlets and outlets in the TPC. The presented techniques are widely applicable to other large-scale, noble-liquid detectors
Designing a Tool for Evacuation Plan Validation: Multi-Agent Simulations with Persona-Based UI
Get PDFNatural disasters (such as earthquakes) are unpredictable events that cannot be foreseen, so the unique strategy we have to reduce their impact and the risks for the citizens is to do prevention. In this context, we propose a methodology we followed to develop a highly customizable tool aimed at validating urban evacuation plans. Built with a focus on persona-based user interface (UI) design, the tool leverages software engineering methodologies to ensure scalability, dynamicity (e.g., simulating unpredictable events during the disaster), and adaptive UI for diverse user groups, including urban planners, civil protection agencies, and safety plan managers. By integrating agent-based models with Geographic Information Systems, the tool provides data-driven simulations that can be used to validate evacuation strategies. The tool was evaluated through two case studies conducted considering various urban environments, enabling iterative development through ongoing requirements elicitation and refinement in collaboration with the user groups