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Macroscopic and microscopic aspects of particle acceleration by cosmic shocks
Get PDFCosmic collisionless shocks are highly energetic phenomena in which different non-thermal processes take place. Above all, particle acceleration is arguably the most important, and observations of its signatures can be a powerful tool to constrain the local plasma and magnetic properties at the acceleration site.
Within large-scale structures, the presence of cosmic rays can be revealed by means of different detection approaches: relativistic electrons can emit in radio via synchrotron radiation (radio relics), while energetic protons can interact with thermal protons of the intracluster medium and emit in the gamma-ray band. Both electrons and protons should in principle be accelerated by the first order Fermi acceleration mechanism known as diffusive shock acceleration: however, only evidence of cosmic-ray electrons has been detected so far in galaxy clusters, while no signatures of cosmic-ray proton have been reported.
With a comprehensive analysis from 'macroscopic' to 'microscopic' scales, I address the missing gamma-ray issue by means of advanced numerical simulations, in which extragalactic magnetic fields are evolved together with the dynamics of large-scale structures. The primary factor at play is obliquity, the angle between the shock propagation direction and the magnetic field. I first determine the distribution of obliquity in cosmological simulations as a function of the medium in which the shock takes place. Then, I detect a pattern in the arrangement of the magnetic field around filaments and perform a quantitative study of the topological properties of the magnetic field surrounding the cosmic web. Finally, shocks in filaments are more closely investigated with new particle-in-cell simulations on much smaller scales, where the actual acceleration efficiency by realistic shocks can be measured.
The new insights obtained from these numerical simulations provide a tool for the correct interpretation of observations and to estimate the magnetic properties that can be inferred, e.g. from Faraday rotation measurements
Catalytic hydrogenation of vegetable oils derivatives
Get PDFDuring this project the catalytic hydrogenation of a mixture of fatty acids derivatives was performed in two different reactors (discontinuous batch and continuous flow); the attention was pointed out on the type of the catalyst employed, involving a screening among different noble metals and support with optimization of the reaction parameters.
Interesting results were obtained in batch reactions with 0.3% wt Pd/C at 4 bar of H2 and 90°C, ensuring full conversion of the starting material and complete selectivity towards the saturated compounds. An insight of the kinetics of the reaction was performed, conducting the reaction for different time (0-6 hours). Also, fundamental parameters such as H2 pressure, stirring rate, temperature, metal type and support were evaluated for determining the most advantageous conditions to guarantee complete starting material conversion and high yields of desired products. The same tests were then performed employing a continuous flow reactor, confirming the high activity of 0.3% wt Pd/C at low contact time of 0.2 min.
Despite stunning results were achieved with a single batch (discontinuous) or for low reaction time (1h in continuous), the catalyst performance started to worsen for multiple batch or longer time respectively. Investigations on the cause were executed, excluding immediately metal leaching thanks to ICP-AES analysis. Deactivation was attributable to absorption of reactants on the catalyst surface, which could lead to formation of oligomers. It was found that the deactivation rate, in the continuous reactor, was directly dependent on the hydrogen pressure, the contact time but even more importantly to the composition of the starting material: an increase of poly-unsaturated fatty acids derivatives affected negatively the catalyst stability, causing a faster decline of conversion and higher decrease in selectively. This was associated to a strong adsorption with consequent formation of oligomers, which occupied the active site, worsening the catalyst’s performance
Application and comparison between non-invasive and invasive methods in the study of skin annexes diseases
Get PDFIntroduzione
Lo scopo dello studio è valutare l’accuratezza diagnostica delle metodiche strumentali non invasive, in particolare dermoscopia, tomografia a coerenza ottica (OCT ) e microscopia confocale (RCM), nelle patologie degli annessi cutanei, confrontate con le metodiche invasive (biopsia ed exeresi chirurgica).
Materiali e metodi
È stato effettuato uno studio prospettico osservazionale in pazienti afferenti all’ambulatorio di Malattie degli Annessi Cutanei, dell’U.O. di Dermatologia dell’Azienda Ospedaliero - Universitaria di Bologna IRCCS Policlinico di Sant’Orsola, Dipartimento di Medicina Specialistica Diagnostica e Sperimentale (DIMES) dell’Università di Bologna, della durata di tre anni. Le metodiche di OCT e RCM sono state effettuate c/o il Policlinico di Modena, U.O. Dermatologia. Le patologie incluse comprendono malattie dei capelli e malattie ungueali. La prima parte dello studio si è focalizzata sullo studio delle metodiche non invasive, la seconda parte si è basata sulla conferma istologica del sospetto diagnostico inziale. Nella terza parte dello studio si è effettuato un confronto tra le diverse metodiche e una valutazione dell’accuratezza diagnostica delle stesse nelle malattie dei capelli e delle unghie.
Risultati
Sono stati valutati 231 pazienti (135 con diagnosi di malattie dei capelli e del cuoio capelluto; 96 con malattie delle unghie). In specifico, siamo riusciti a stabilire una corrispondenza tra i parametri tricoscopici, istologici e RCM per l’alopecia fibrosante frontale, l’alopecia areata incognita, la tinea capitis e il lichen simplex cronico. Nell’ambito delle malattie delle unghie, abbiamo valutato le correlazioni tra onicoscopia ed OCT per il lichen planus ungueale, la psoriasi ungueale, l’onicomicosi e il tumore glomico.
Conclusioni
Riteniamo lo studio molto utile, in quanto reputiamo che una conoscenza ancora più approfondita degli strumenti non invasivi per la diagnosi precoce di malattie degli annessi cutanei sia importante a diversi livelli, come ad esempio sui tempi di diagnosi e sulla riduzione dei costi di gestione.Introduction
The purpose of the study is to evaluate the diagnostic accuracy of non-invasive instrumental methods, in particular dermoscopy, optical coherence tomography (OCT) and confocal microscopy (RCM), in the skin appendages disorders, compared with invasive methods (biopsy and surgical excision).
Materials and methods
A prospective observational study was performed in patients belonging to the Outpatient Department of Skin Annexes Diseases, of the Dermatology Unit of the Hospital - University of Bologna IRCCS Policlinico di Sant’Orsola, Department of Specialized Diagnostic and Experimental Medicine (DIMES) of the University of Bologna, lasting three years. The OCT and RCM methods were carried out at the Policlinico di Modena, Dermatology Unit. Evaluated diseases included hair diseases and nail diseases. The first part of the study focused on the study of non-invasive methods, the second part was based on the histological confirmation of the initial diagnostic suspicion. In the third part of the study, a comparison was made between the different methods and an evaluation of their diagnostic accuracy in hair and nail diseases.
Results
231 patients were evaluated (135 diagnosed with hair and scalp diseases; 96 with nail diseases). Specifically, we were able to establish a correspondence between the trichoscopic, histological and RCM parameters for frontal fibrosing alopecia, alopecia areata incognita, tinea capitis and chronic lichen simplex. In nail diseases, we evaluated the correlations between onychoscopy and OCT for nail lichen planus, nail psoriasis, onychomycosis and glomus tumor.
Conclusions
We believe that the study is very useful, as we believe that an even deeper knowledge of non-invasive tools for the early diagnosis of skin annexes diseases is important at various levels, such as for example on diagnosis times and reduction of management costs
Modeling and optimization techniques for advanced vehicular networking
Get PDFThis thesis deals with optimization techniques and modeling of vehicular networks.
Thanks to the models realized with the integer linear programming (ILP) and the heuristic ones, it was possible to study the performances in 5G networks for the vehicular. Thanks to Software-defined networking (SDN) and Network functions virtualization (NFV) paradigms it was possible to study the performances of different classes of service, such as the Ultra Reliable Low Latency Communications (URLLC) class and enhanced Mobile BroadBand (eMBB) class, and how the functional split can have positive effects on network resource management. Two different protection techniques have been studied: Shared Path Protection (SPP) and Dedicated Path Protection (DPP). Thanks to these different protections, it is possible to achieve different network reliability requirements, according to the needs of the end user.
Finally, thanks to a simulator developed in Python, it was possible to study the dynamic allocation of resources in a 5G metro network. Through different provisioning algorithms and different dynamic resource management techniques, useful results have been obtained for understanding the needs in the vehicular networks that will exploit 5G. Finally, two models are shown for reconfiguring backup resources when using shared resource protection
Integrated Study of the Tectonic Evolution of the Mid-Norwegian Passive Margin
Get PDFThis thesis investigates the brittle tectonic evolution of the Mid-Norwegian Passive Margin (MNPM) in time and through space. A multidisciplinary and multiscalar workflow has been conceptualised and applied to collect data at several scales of observations to characterise the complex brittle evolution of the margin.
The thesis first presents a high-resolution structural-geochronological study of a regional fault zone, the Lærdal-Gjende Fault in southwestern Norway. Then it presents an integrated reconstruction of the polyphase brittle evolution of the MNPM. The applied approach relied on remote sensing detection of lineaments, meso- and microstructural analysis of representative faults, paleostress inversion and K-Ar dating of fault gouges and altered rocks coupled with their mineralogical characterisation. The proposed structural-geochronological model of the MNPM includes six time-constrained tectonic events.
In addition, this thesis tested an innovative research theme, by providing the first clumped isotopic constraints on calcite from basement rocks and faults and by proposing their interpretation through time and in space in the context of the polyphase evolution of the margin. Clumped isotope thermometry has been applied on calcite veins associated with brittle structures. The variable geochemical results indicate that calcites derive from highly mixed meteoric and marine fluids, locally circulating within paleosols in surficial environments, during a polyphase evolution.
Lastly, this thesis contains the results of the 3D modelling of the petrophysical properties and fracture distribution of fractured, weathered, dated basement outcrops, which are analogues of the offshore, fractured and weathered, structural highs that host the main hydrocarbon reserves of unconventional plays in Norway. Analysis of Virtual Outcrop Models integrated with Discrete Fracture Network modelling assisted the investigation of the relationships between sub-seismic and seismic-resolution fractures and the bulk permeability of the fractured and weathered basement volumes
Development, mechanical characterization and qualification in liquid lead of stainless steels for structural applications in the future fission and fusion nuclear reactors
Get PDFThe research activity carried out in the Brasimone Research Center of ENEA concerns the development and mechanical characterization of steels conceived as structural materials for future fission reactors (Heavy Liquid Metal IV Generation reactors: MYRRHA and ALFRED) and for the future fusion reactor DEMO. Within this framework, two parallel lines of research have been carried out: (i) characterization in liquid lead of steels and weldings for the components of the IV Generation fission reactors (GIV) by means of creep and SSRT (Slow Strain Rate Tensile) tests; (ii) development and screening on mechanical properties of RAFM (Reduced Activation Ferritic Martensitic) steels to be employed as structural materials of the future DEMO fusion reactor. The doctoral work represents therefore a comprehensive report of the research carried out on nuclear materials both from the point of view of the qualification of existing (commercial) materials for their application in the typical environmental conditions of 4th generation fission reactors operating with lead as coolant, and from the point of view of the metallurgical study (with annexed microstructural and mechanical characterization of the selected compositions / Thermo Mechanical Treatment (TMT) options) of new compositional variants to be proposed for the “Breeding Blanket” of the future DEMO Fusion Reactor
Development and validation of an echocardiography score for diagnosis of cardiac masses
Get PDFBackground
Echocardiography is the cornerstone in the evaluation of cardiac masses and provides accurate characterization. Despite, its accuracy in diagnosis of cardiac masses (CM) remains challenging and, up to date, no validated diagnostic algorithm is validated.
Purpose
The aim of our study was to evaluate the diagnostic accuracy of echocardiography, to identify the echocardiographic predictors of malignancy and to develop and then validate a multiparametric echocardiographic score that could be used to estimate the likelihood of the histological nature of a CM.
Materials and methods
The final sample consisted of 273 consecutive patients who had a 2D-echocardiographic evaluation and a histologic diagnosis. Logistic regression was performed to evaluate the ability of echocardiographic findings to discriminate benign versus malignant masses, then a scoring system was developed and validated in a separate test cohort.
Results
Of the 322 patients initially included in the Bologna Cardiac Masses Registry, 13 with a poor acoustic window, 27 with no histological examination patients and 9 extra-cardiac masses were excluded. In the remaining 273 patients, classical 2-D echocardiogram identified 249 masses with a diagnostic accuracy of 88%. A weighted score [Diagnostic Echocardiographic Mass (DEM) Score] ranging from 0 to 9 was obtained from 6 variables: infiltration, polylobate mass, moderate-severe pericardial effusion. The AUC for the score was 0.965 (95% CI [0.938-0.993]). In a logistic regression analysis using the DEM score as a predictor, the likelihood of malignant CM increased more than 4 times for a 1-unit increase in the score (OR=4.468; 95% CI 2.733-7.304). A score < 3 denoted a high probability of a benign diagnosis, and a score ≥ 5 points corresponded to a higher risk of malignancy.
Conclusion
2D-Echocardiography provides a high diagnostic accuracy in identifying cardiac masses and our multiparametric echocardiographic score could be useful to predict the histological nature of cardiac masses
Neonatal outcomes following maternal SARS-CoV-2 infection in pregnancy - longitudinal follow-up and assessment of transplacental antibody transfer
Get PDFBACKGROUND: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in pregnancy has been associated with multiple adverse pregnancy outcomes, including the risk of in utero mother-to-child transmission. Short- and long-term outcomes of SARS-CoV-2 exposed neonates and the extent to which maternal SARS-CoV-2 antibodies are transferred to neonates are still unclear.
METHODS: Prospective observational study enrolling neonates born to mothers with SARS-CoV-2 infection in pregnancy, between April 2020-April 2021. Neonates were evaluated at birth and enrolled in a 12-month follow-up. SARS-CoV-2 IgG transplacental transfer ratio was assessed in mother-neonate dyads at birth. Maternal derived IgG were followed in infants until negativizing.
RESULTS: Of 2745 neonates, 106 (3.9%) were delivered by mothers with SARS-CoV-2 infection in pregnancy. Seventy-six of 106 (71.7%) mothers were symptomatic. Median gestational age and mean birth weight were 39 weeks (range 25+5-41+4) and 3305 grams (SD 468). Six of 106 (6%) neonates were born preterm, without significant differences between asymptomatic and symptomatic mothers (P=0.67). No confirmed cases of in utero infection were detected. All infants had normal cerebral ultrasound and clinical evaluation at birth and during follow-up, until a median age of 7 months (range 5-12). All mothers and 96/106 (90.5%) neonates had detectable SARS-CoV-2 IgG at birth. Transplacental transfer ratio was higher following second trimester maternal infections (mean 0.940.46 versus 1.070.64 versus 0.750.44, P=0.039), but was not significantly different between asymptomatic and symptomatic women (P=0.20). IgG level in infants progressively decreased after birth: at 3 months 53% (51/96) and at four months 68% (63/96) had lost maternal antibodies respectively. The durability of maternal antibodies was positively correlated to the IgG level at birth (r=0.66; P<0.00001).
CONCLUSIONS: Maternal SARS-CoV-2 infection was not associated with increased neonatal or long-term morbidity. No cases of confirmed in utero infection were detected. Efficient transplacental IgG transfer was found following second trimester maternal infections
Analisi multifattoriale e di sicurezza alimentare di gasteropodi marini destinati al consumo umano
Get PDFThe present thesis aims to evaluate a method to assess the viability; estimate the bacterial and viral (Hepatitis A and Norovirus) contamination; describe how some parameters change during a week in refrigerated condition and after 24 hours of immersion; estimate indole-producing bacteria and biogenic amines; evaluate the presence of saxitoxin and tetrodotoxin.
The method to assess the viability using sea salt is easy to apply. Marine gastropods did not accumulate fecal contaminants, but vibrios due to their feeding. The Vibrio spp. load was even higher than the one registered on Ruditapes philippinarum belonging to the same area For what to concern the evaluation during a week in refrigerated condition and after 24 hours of immersion, non-re-immersed gastropods exceeded the acceptable mortality (10%) after three days in refrigerated conditions, but the Vibrio spp. load did not show a significant increase within three days. The TVC was already high from the beginning and its major part consisted of SSOs, which could be explained by gastropods’ feed, such as the Pseudomonas spp. load and the abundance of IPB. The BAs amount was also correlated with viability and had a statistically significant difference within a week on refrigerated conditions, principally because putrescine, tyramine, spermidine, and cadaverine rise in non-re-immersed samples. It also should be noted that the BAs amount was higher on average than the recommendation of literature. Moreover, re-immersed batches showed acceptable viability even after 3 days, and the Vibrio spp. load, TVC, SSOs, and biogenic amines remained almost constant within a week contrary to non-re-immersed samples. Finally, T. mutabilis and B. brandaris did not accumulate NoVs and TTX. We obtained only one positivity of the HAV sample and traces of STX (not at levels toxic to humans).
Our results contribute to identifying food-borne hazards for T. mutabilis and B. brandaris
Exploiting the environment for structural health monitoring: Strategies, algorithms, and technologies
Get PDFA densely built environment is a complex system of infrastructure, nature, and people closely interconnected and interacting. Vehicles, public transport, weather action, and sports activities constitute a manifold set of excitation and degradation sources for civil structures. In this context, operators should consider different factors in a holistic approach for assessing the structural health state. Vibration-based structural health monitoring (SHM) has demonstrated great potential as a decision-supporting tool to schedule maintenance interventions. However, most excitation sources are considered an issue for practical SHM applications since traditional methods are typically based on strict assumptions on input stationarity. Last-generation low-cost sensors present limitations related to a modest sensitivity and high noise floor compared to traditional instrumentation. If these devices are used for SHM in urban scenarios, short vibration recordings collected during high-intensity events and vehicle passage may be the only available datasets with a sufficient signal-to-noise ratio. While researchers have spent efforts to mitigate the effects of short-term phenomena in vibration-based SHM, the ultimate goal of this thesis is to exploit them and obtain valuable information on the structural health state. First, this thesis proposes strategies and algorithms for smart sensors operating individually or in a distributed computing framework to identify damage-sensitive features based on instantaneous modal parameters and influence lines. Ordinary traffic and people activities become essential sources of excitation, while human-powered vehicles, instrumented with smartphones, take the role of roving sensors in crowdsourced monitoring strategies. The technical and computational apparatus is optimized using in-memory computing technologies. Moreover, identifying additional local features can be particularly useful to support the damage assessment of complex structures. Thereby, smart coatings are studied to enable the self-sensing properties of ordinary structural elements. In this context, a machine-learning-aided tomography method is proposed to interpret the data provided by a nanocomposite paint interrogated electrically