Università degli studi di Cagliari
  • Cagliari, Sardinia, Italy
Recent publications
s Bowel inflammation, impaired intestinal epithelial barrier (IEB), and gut dysbiosis could represent early events in Parkinson’s disease (PD). This study examined, in a descriptive manner, the correlation among enteric α-synuclein, bowel inflammation, impairments of IEB and alterations of enteric bacteria in a transgenic (Tg) model of PD before brain pathology. Human A53T α-synuclein Tg mice were sacrificed at 3, 6, and 9 months of age to evaluate concomitance of enteric inflammation, IEB impairments, and enteric bacterial metabolite alterations during the early phases of α-synucleinopathy. The molecular mechanisms underlying the interplay between α-synuclein, activation of immune/inflammatory responses and IEB alterations were investigated with in vitro experiments in cell cultures. Tg mice displayed an increase in colonic levels of IL-1β, TNF, caspase-1 activity and enteric glia activation since 3 months of age. Colonic TLR-2 and zonulin-1 expression were altered in Tg mice as compared with controls. Lipopolysaccharide levels were increased in Tg animals at 3 months, while fecal butyrate and propionate levels were decreased. Co-treatment with lipopolysaccharide and α-synuclein promoted IL-1β release in the supernatant of THP-1 cells. When applied to Caco-2 cells, the THP-1-derived supernatant decreased zonulin-1 and occludin expression. Such an effect was abrogated when THP-1 cells were incubated with YVAD (caspase-1 inhibitor) or when Caco-2 were incubated with anakinra, while butyrate incubation did not prevent such decrease. Taken together, early enteric α-synuclein accumulation contributes to compromise IEB through the direct activation of canonical caspase-1-dependent inflammasome signaling. These changes could contribute both to bowel symptoms as well as central pathology.
The current pandemic situation has led to an extraordinary increase in remote working activities all over the world. In this paper, we conducted a research study with the aim to investigate the Quality of Remote Working Experience (QRWE) of workers when conducting remote working activities and to analyse its correlation with implicit emotion responses estimated from the speech of video-calls or discussions with people in the same room. We implemented a system that captures the audio when the worker is talking and extracts and stores several speech features. A subjective assessment has been conducted, using this tool, which involved 12 people that were asked to provide feedback on the QRWE and assess their sentiment polarity during their daily remote working hours. ANOVA results suggest that speech features may be potentially observed to infer the QRWE and the sentiment polarity of the speaker. Indeed, we have also found that the perceived QRWE and polarity are strongly related.
Context Cycling is a climate-friendly means of transport that enables people to reduce their use of motorized transport and makes human settlements more inclusive and resilient. In Italy, the development of cycling has recently been boosted by the approval of Law no. 2/2018, which makes it compulsory for all Italian regions to draw up a regional cycling mobility plan. Objective To meet this regulatory provision, the Region of Sardinia approved the Regional Plan for Cycling Mobility in December 2018. Drawn up by the Sardinian Regional Transport Agency and the transportation research group of the University of Cagliari, the plan aims to lay out a regional cycle network to promote the use of the bicycle as a means of transport for both every day and tourist–recreational needs. One of the main objectives of the plan is to make the inland areas of the island more accessible, as the development of such areas tends to have been neglected compared to the coastal areas linked to seaside tourism. Hence, the plan intends to contribute to the increase of tourist flows into rural areas, which can be a strategic segment of local development. Results By analysing the methodology adopted to lay out Sardinia’s regional cycle network, the aim of the current paper is to show how the planning of an integrated cycle network in an island context can improve sustainable mobility and accessibility in the rural areas through which it passes. Furthermore, our analysis indicates that many rural settlements along the routes of the planned cycle network are sufficiently near each other for people to travel between them by bicycle. Conclusions Therefore, the cycling infrastructure could prompt a sustainable increase in the accessibility and connectivity of inland areas and stimulate the formation of clusters of small, interconnected towns and villages.
Background Long COVID-19 syndrome is a complex of symptoms that occurs after the acute SARS-CoV-2 infection, in the absence of other possible diagnoses. Studies on Long COVID-19 in pediatric population are scanty and heterogeneous in design, inclusion criteria, outcomes, and follow-up time. The objective of the present study is to assess the prevalence of Long COVID-19 syndrome in a cohort of Italian pediatric primary care patients, observed for a period of time of 8 to 36 weeks from healing. Prevalence was also assessed in a cohort of pediatric patients hospitalized during acute infection. Methods Data concerning 629 primary care patients with previous acute SARS-CoV-2 infection were collected by a questionnaire filled in by Primary Care Pediatrician (PCP). The questionnaire was administrated to patients by 18 PCPs based in 8 different Italian regions from June to August 2021. Data concerning 60 hospitalized patients were also collected by consultation of clinical documents. Results Cumulative incidence of Long COVID-19 resulted to be 24.3% in primary care patients and 58% in hospitalized patients. The most frequently reported symptoms were abnormal fatigue (7%), neurological (6.8%), and respiratory disorders (6%) for the primary care cohort. Hospitalized patients displayed more frequently psychological symptoms (36.7%), cardiac involvement (23.3%), and respiratory disorders (18.3%). No difference was observed in cumulative incidence in males and females in both cohorts. Previous diseases did not influence the probability to develop Long COVID-19. The prevalence of Long COVID-19 was 46.5% in children who were symptomatic during acute infection and 11.5% in asymptomatic ones. Children aged 0 to 5 years had a greater risk to develop respiratory symptoms, while adolescents (aged 11–16 years) had a greater risk to develop neurological and psychological Long COVID-19 symptoms. Conclusions Our study demonstrates that Long COVID-19 is a reality in pediatric age and could involve even patients with mild or no acute symptoms. The results stress the importance of monitoring primary care pediatric patients after acute COVID-19 infection and the relevance of vaccination programs in pediatric population, also in order to avoid the consequences of Long COVID-19 syndrome.
The state of the art of earthen architecture and vernacular built heritage comprises a complex set of issues that range from fundamental problematic recognition to anthropological and cultural studies and, more recently, to technological and experimental analyses. This paper addresses the development of the field, following the milestones of the international literature and pursuing a reflective-theory approach within a historical framework. It aims to explore the main contributions that have enhanced vernacular heritage and earthen architecture as specific domains, from pioneering public awareness essays to institutional expertise guidelines. Finally, in addition to the literature review process, this paper considers the recent corpus of recommendations from conservation management reference institutions, the updating of the operative problematic of earthen vernacular built heritage, and the relevance of local community involvement in facing increasing challenges.
Machine learning techniques have recently become the norm for detecting patterns in financial markets. However, relying solely on machine learning algorithms for decision-making can have negative consequences, especially in a critical domain such as the financial one. On the other hand, it is well-known that transforming data into actionable insights can pose a challenge even for seasoned practitioners, particularly in the financial world. Given these compelling reasons, this work proposes a machine learning approach powered by eXplainable Artificial Intelligence techniques integrated into a statistical arbitrage trading pipeline. Specifically, we propose three methods to discard irrelevant features for the prediction task. We evaluate the approaches on historical data of component stocks of the S&P500 index and aim at improving not only the prediction performance at the stock level but also overall at the stock set level. Our analysis shows that our trading strategies that include such feature selection methods improve the portfolio performances by providing predictive signals whose information content suffices and is less noisy than the one embedded in the whole feature set. By performing an in-depth risk-return analysis, we show that the proposed trading strategies powered by explainable AI outperform highly competitive trading strategies considered as baselines.
Higher order spectral analysis is used for structural damage detection based on nonlinear vibro-acoustic modulations. A combined low-frequency vibration and high-frequency ultrasonic excitation is used, leading to nonlinear vibro-acoustic modulated responses in the presence of structural damage. The response data are analysed using a modulation signal bispectrum and bicoherence. The analysis of local amplitude and phase of these characteristics is proposed for structural damage detection. The method is illustrated using numerical simulations and experimental data. The latter involves impact damage detection in composite plates. The results show that – in contrast to the classical higher order spectral analysis – the method identifies all nonlinear damage-related coupled components correctly, distinguishes these components from undesired non-damage related modulations, and therefore shows a potential for reliable structural damage detection.
In consecutive studies on flexomagneticity (FM), we investigate the flexomagnetic reaction of a vibrating squared multi-physic beam in finite dimensions. It is assumed that the bending and shear deformations cause rotary inertia. In the standard type of the Timoshenko beam the rotary inertia originated from shear deformations has been typically omitted. It means the rotary inertia resulting from shear deformation is a new concept considered here. Thus, the novelty in this work is that the effect of shear deformation's rotary inertia (SDRI) on the FM response will be considered in detail. When it comes to nanosize, the well-posed nonlocal elasticity assumption of Eringen can be worth choosing. In this study, the weak form (differential) of strain-driven nonlocal theory is taken into hand for easiness. The procedure of solution will be in regard to the advantage of the Galerkin weighted residual technique based on an analytical flow for the nanobeam located at simply-simply supported ends. Several separate studies will show how SDRI and FM can influence each other. The observations give some new achievements in the series of studies on FM. It has been earned that the SDRI can directly impress the flexomagnetic feature of small-scale actuators.
This paper reports experimental investigations of the effects of various parameters on visible laser beam attenuation characteristics for organic pure polyethylene oxide (PEO) thin films. The pure PEO thin films with various thicknesses were prepared using the solution casting method. The attenuation characteristics of the prepared pure PEO were investigated using diode pumped solid state (DPSS) laser (with wavelength 532 nm), and He–Ne laser (with wavelength 632.8 nm). For both laser systems the influences of different control parameters (including linear, circular polarization states of the laser output, the separation distance between the thin films and the optical detector, and the laser beam incidence angle on thin films) on laser beam power attenuation were obtained. The DPSS laser beam output power with linear polarization has greater attenuation characteristics than other control parameters used in this work.
We consider anti-plane motions of an elastic plate taking into account surface energy within the linear Gurtin–Murdoch surface elasticity. Two boundary-value problems are considered that describe complete shear dynamics of a plate with free faces or with free and clamped faces, respectively. These problems correspond to anti-plane dynamics of an elastic film perfectly or non-perfectly attached to a rigid substrate. Detailed analysis of dispersion relations is provided. In particular, the influence of the ratio of a plate thickness to characteristic length on the dispersion curves is analysed. This article is part of the theme issue ‘Wave generation and transmission in multi-scale complex media and structured metamaterials (part 1)’.
In this paper, we study wave propagation in elastic plates incorporating honeycomb arrays of rigid pins. In particular, we demonstrate that topologically non-trivial band-gaps are obtained by perturbing the honeycomb arrays of pins such that the ratio between the lattice spacing and the distance of pins is less than 3; conversely, a larger ratio would lead to the appearance of trivial stop-bands. For this purpose, we investigate band inversion of modes and calculate the valley Chern numbers associated with the dispersion surfaces near the band opening, since the present problem has analogies with the quantum valley Hall effect. In addition, we determine localized eigenmodes in strips, repeating periodically in one direction, that are subdivided into a topological and a trivial section. Finally, the outcomes of the dispersion analysis are corroborated by numerical simulations, where a time-harmonic point source is applied to a plate with finite arrays of rigid pins to create localized waves immune to backscattering. This article is part of the theme issue ‘Wave generation and transmission in multi-scale complex media and structured metamaterials (part 1)’.
This work focuses on the preparation of a pH-sensitive antimicrobial drug delivery system based on Mesoporous silica nanoparticles (MSN), functionalized with aminopropyl-triethoxysilane (MSN-NH2), triethylenetetramine (MSN-TETA) and poly-L-lysine (MSN-NH2-PLL, MSN-TETA-PLL), and loaded with the flavonoid quercetin. The systems were fully characterized by means of several techniques. Besides the role of the different functionalization of MSNs, this work aimed to optimize both loading and release processes of quercetin, using two different ethanol-water mixtures as solvent, namely EtOH:H2O mixtures at the ratios 80:20 and 50:50. Whereas loading was higher using the 80:20 solvent mixture, a more efficient release was ascertained using the solvent mixture 50:50 as demonstrated by the release kinetics, and also by the amount of the released drug. It was suggested that in the presence of less ethanol, quercetin solubility decreases, and a physical adsorption of quercetin at the functional groups of MSNs can be favoured with respect to a random distribution over many surface sites with which only weak interactions can occur. This means that in the presence of high amount of ethanol, used very often when dealing with poorly water-soluble drugs, the impregnation process becomes dominant, loading increases significantly, but subsequently burst release of high amounts of drug occurs. In this work, using the specific case of quercetin, we found a more sustained release as the result of a predominant adsorption mechanism due to the careful choice of the solvent mixture composition during the loading step. Moreover, the new drug delivery system allowed for a significant improvement in quercetin stability and the optimal release concentration attainment.
Purpose: To describe a case of an infective vitreitis with an exudative retinal detachment in a 56-year-old lady who was previously affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Observations: A broad workup for infections including the main viruses and bacteria was performed. Salivary droplets, tear film and vitreous samples were collected, resulting positive only for Epstein-Barr virus (EBV). Viraemia and immunoglobulin M for EBV negative, whereas immunoglobulin G positive. The patient showed a simultaneous painless erosion on the right margin of the tongue that's with the lab swab demonstrated the presence of EBV at the same time the vitreitis in the left eye was present. Conclusions and importance: Our speculation is that a continuous use of the mask, especially in immunocompromised subjects, it might create a new route for spreading infectious oral agents in the ocular area, and this case is a warning for all the ophthalmologists that have to be aware of this threatening possibility in the COVID era.
In this paper we propose a novel distributed local interaction protocol for networks of multi-agent systems (MASs) in a multi-dimensional space under directed time-varying graph with the objective to achieve secure rendezvous or static containment within the convex hull of a set of leader agents. We consider the scenario where a set of anonymous adversarial agents may intrude the network (or may be hijacked by a cyber-attack) and show that the proposed strategy guarantees the achievement of the global objective despite the continued influence of the adversaries which cannot be detected nor identified by the collaborative agents. We characterize the convergence properties of the proposed protocol in terms of the characteristics of the underlying network topology of the multi-agent system. Numerical simulations and examples corroborate the theoretical results.
Concrete Filled Steel Tubular (CFST) K-joints employed for truss structures gained high interest in the last years due to their widespread use in engineering practice. The overall performances of these joints can be efficiently improved by using steel studs welded in the inner surface of the steel chord filled with the concrete, avoiding punching shear failure, and improving the overall strength and ductility. However, a reliable prediction of the structural behavior of the joints is outmost of importance for the assessment of the capacity of new and existing structures, and there are no standardized design methods nowadays. In this paper, the structural performances of CFST K-joints with and without steel studs are investigated by Finite Element Modelling (FEM) approach with the aim to provide a predictive tool for the design. A comprehensive discussion of the key parameters that govern the FEM procedure as well as the calibration of the FE models was provided to give the basis for a reliable modelling of CFST K-joints with and without studs for the predictions of the load–displacement/strain response and the strength, considering the main failure mechanisms. In this context, in addition to the detailed FEM of CFST K-joints with steel studs, a simplified equivalent FEM approach is proposed to reduce computational effort keeping the same accuracy.
Relating damage development to the specific environmental conditions is of paramount importance to design effective conservation strategies for archaeological and historical sites. For this reason, artificial weathering is a highly debated topic in materials science applied to Cultural Heritage. In this work, we report on the weathering of decorated earthen plasters from Templo Pintado in Pachacamac (Region of Lima, Peru) and define a methodology to accelerate aging of painted raw earth surfaces. Weathering was simulated by exposing the surfaces to wet-dry and sandblasting cycles and resulting damage was estimated via the amount of material removed from the original surface. The results are in agreement with weathering dynamics observed in situ, which allows designing suitable methodology for the preparation of samples to be used in testing procedures addressing the preservation of surfaces.
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4,355 members
Amit Kumar
  • Department of Electrical and Electronic Engineering
Gianfranca Carta
  • Department of Biomedical Science
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Via Università 40, 09100, Cagliari, Sardinia, Italy
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Maria Del Zompo
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www.unica.it
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