University of Modena and Reggio Emilia
Archivio istituzionale della ricerca - Università di Modena e Reggio EmiliaNot a member yet
116400 research outputs found
Sort by
Sviluppo di nuovi strumenti, approcci e sistemi basati sulle nanotecnologie per la termoelettricità e la raccolta di energia
No full textIl successo globale dipende dalla generazione, raccolta e gestione del budget energetico. L'elettricità è l'energia moderna più influente, con utilizzi di mercato in rapida crescita, generati principalmente da tecnologie basate sulla combustione. Tali tecnologie e l'elettronica di consumo diffusa generano molto calore sprecato e "calore di bassa qualità", calore che è troppo basso, disomogeneo, discontinuo o impossibile da recuperare con metodi convenzionali.
I nanomateriali e la nanotecnologia stanno rendendo i generatori termoelettrici (TEG), che convertono il calore in elettricità senza parti in movimento, più attraenti. Inoltre, c'è un forte impegno politico per il recupero energetico e una rinnovata attenzione all'esplorazione spaziale, un settore correlato ai TEG. Questo studio esamina la risposta termoelettrica a temperatura intermedia e alta dei materiali nanostrutturati innovativi. I risultati hanno fatto conoscere i meccanismi di drogaggio, la nanostrutturazione e le prestazioni termoelettriche e hanno fatto progredire lo sviluppo di materiali di conversione energetica ad alta efficienza.
Per quanto riguarda i materiali, gli studi riportati in questa tesi includono ZnO drogato con Al, ZnSe drogato con Fe, ZnSe drogato con Cu, Bi2Te3 drogato con Se e SnO drogato con Mg, e si concentrano sull'impatto del drogaggio e della nanostrutturazione sulle proprietà termoelettriche. Viene condotta un'analisi sistematica dell'influenza di diverse condizioni di temperatura sulle proprietà termoelettriche. Sono stati utilizzati due approcci per la preparazione sia di nanoparticelle che di film sottili dei materiali: sintesi idrotermica e sputtering magnetron. Per quanto riguarda le metodologie e le tecniche di caratterizzazione, è stata utilizzata la XRD per eseguire la caratterizzazione strutturale. La topografia superficiale è stata studiata utilizzando AFM. La morfologia dei nanocristalli è stata esaminata tramite SEM e l'analisi della composizione elementare è stata condotta tramite EDX. Le proprietà di trasporto sono state misurate con il metodo a 4 sonde nell'intervallo di temperatura 25–350°C.
La tesi è organizzata come segue. I capitoli da 1 a 3 coprono gli argomenti sopra menzionati, vale a dire l'introduzione alla termoelettricità su scala nanometrica, materiali e metodi e tecniche per nanostrutture termoelettriche. Il capitolo 4 studia le proprietà TE dei film sottili di ZnO (AZO) drogato con Al, sottolineando l'influenza di diverse concentrazioni di drogaggio di Al (2–8 at.%) sulle caratteristiche di trasporto elettrico e termoelettrico. I film sottili di AZO, con uno spessore di 300 nm, sono stati depositati tramite sputtering magnetron RF. Le caratterizzazioni strutturali e morfologiche indicano che livelli di drogaggio aumentati determinano una migliore conduttività elettrica, con resistività che scende al di sotto di 2 × 10–3 Ohm˖cm al 3 at.% di Al. Il coefficiente di Seebeck è stato visto variare tra 22 e 33 μV/K, raggiungendo un picco all'8 at.% di drogaggio. Nel capitolo 5, studiamo l'impatto del drogaggio di Fe2+ sulle caratteristiche TE delle nanoparticelle di ZnSe prodotte dalla tecnica idrotermale. L'indagine SEM ha dimostrato agglomerati di nanocristalliti di dimensioni variabili a tutti i livelli di drogaggio, mentre la spettroscopia XRD e Raman ha convalidato la struttura cubica dei campioni. Le caratteristiche di trasporto elettrico sono state migliorate con concentrazioni di drogaggio Fe potenziate e il fattore di potenza è stato aumentato da 13 μWm–1K–2 a 120 μWm–1K–2, con un fattore di potenza massimo di 9 × 10–3 Wm–1K–2 a 150°C.Global success depends on energy budget generation, harvesting, and management. Electricity is the most influential modern energy, with rapidly rising market uses, mostly generated by combustion-based technologies. Such technologies and pervasive consumer electronics generate a lot of wasted heat and 'low grade heat'—heat that is too low, inhomogeneous, discontinuous, or impossible to recover by conventional methods.
Nanomaterials and nanotechnology are making thermoelectric generators (TEGs), which convert heat-to-electricity without moving parts, more appealing. In addition, there is strong political commitment to energy recovery and renewed attention on space exploration, a TEG-related industry. This study examines innovative nanostructured materials' intermediate and high-temperature thermoelectric response. The findings shed knowledge on doping mechanisms, nanostructuring, and thermoelectric performance and advance the development of high-efficiency energy conversion materials.
On the material side, the studies reported in this thesis include Al doped ZnO, Fe doped ZnSe, Cu doped ZnSe, Se doped Bi2Te3 and Mg doped SnO, and focus on the impact of doping and nanostructuring on the thermoelectric properties. Systematic analysis of the influence of different temperature conditions on thermoelectric properties is conducted. Two approaches for the preparation of both nanoparticles and thin films of the materials were used: hydrothermal synthesis and magnetron sputtering. On the side of characterization methodologies and techniques, XRD was used to perform structural characterisation. Surface topography was investigated using AFM. Morphology of the nanocrystals was examined by SEM and elemental composition analysis was conducted by EDX. The transport properties were measured by the 4-probe method in the temperature range 25–350°C.
The thesis is organized as follows. Chapters 1 to 3 covers the topics mentioned above, namely the introduction to nanoscale thermoelectricity, thermoelectric nanostructures materials and methods and techniques. Chapter 4 studies the TE properties of Al-doped ZnO (AZO) thin films, emphasising the influence of different Al doping concentrations (2–8 at.%) on electrical and thermoelectric transport characteristics. The AZO thin films, measuring 300 nm in thickness, were deposited via RF magnetron sputtering. Structural and morphological characterisations indicate that increased doping levels result in improved electrical conductivity, with resistivity falling below 2 × 10–3 Ohm˖cm at 3 at.% Al. The Seebeck coefficient was seen to vary between 22 and 33 μV/K, reaching a peak at 8 at.% doping. In chapter 5, we study the impact of Fe2+ doping on the TE characteristics of ZnSe nanoparticles produced by the hydrothermal technique. SEM investigation demonstrated agglomerates of nanocrystallites of varying sizes at all doping levels, whereas XRD and Raman spectroscopy validated the cubic structure of the samples. Electrical transport characteristics were improved with enhanced Fe doping concentrations and the power factor was increased from 13 μWm–1K–2 to 120 μWm–1K–2, with a maximum power factor of 9 × 10–3 Wm–1K–2 at 150°C. Chapter 6 focus on the details study of the influence of copper doping on the TE characteristics of ZnSe nanoparticles produced by the hydrothermal technique. Our research indicates that Cu doping markedly increases electrical conductivity and the Seebeck coefficient, resulting in enhanced power factors. The Cu-doped ZnSe nanostructures showed various phases with a nanocrystalline shape, characterised by an average grain size of less than 5 nm
Different patterns of neurogenic quadrilateral space syndrome: a case series of undefined posterior shoulder pain
No full textBackground: Quadrilateral space syndrome is a painful disorder of the shoulder caused by static or dynamic entrapment of the axillary nerve and the posterior humeral circumflex artery. It was first described in 1983; however, it is an uncommon syndrome that initially presents with nonspecific shoulder pain or selective deltoid atrophy, and diagnosis is often delayed owing to its rarity. Young athletes of overhead sports are more commonly affected by this syndrome. Symptoms of quadrilateral space syndrome include silent deltoid atrophy, persistent posterior shoulder pain, paresthesias, and tenderness over the quadrilateral space. Vascular symptoms may involve thrombosis and embolisms of the upper limb. Instrumental tests and imaging are not always conclusive, leading to frequent misdiagnosis of the syndrome. Patients and methods: The aim of this study is to present a case series of four patients diagnosed with neurogenic quadrilateral space syndrome, describe different clinical presentations, and suggest tips for diagnosing this syndrome. All patients underwent a detailed medical history collection, were interviewed about the sports and hobbies they engaged in, and received a comprehensive clinical examination of the neck and shoulder. Patients also underwent diagnostic exams such as magnetic resonance imaging (MRI) and electromyography. An ultrasound-guided injection of local anesthetic was performed into the quadrilateral space. Results: All patients affected by neurogenic quadrilateral space syndrome underwent conservative treatment, which included a rehabilitation program. Only one out of four patients experienced complete resolution of symptoms and did not require surgical decompression. Conclusions: To properly treat this rare syndrome, we propose classifying it as either “dynamic” or “static,” on the basis of the clinical history, MRI findings, and physical examination. The study includes a rehabilitation program that was effective for one patient, demonstrating that surgical decompression may be avoidable if the cases are promptly diagnosed and classified. Level of evidence IV according to “The Oxford 2011 Levels of Evidence
DISPOSITIVOS INTEROCLUSALES, Acción y Reacción / DISPOSITIVI INTEROCCLUSALI, Azione e Reazione
No full textAutotransplantation of retained canines unable to undergo orthodontic traction. A clinical report
Get PDFAim: The canine is the tooth that, together with the third molar, presents the highest risk of inclusion: 85% of these teeth are located in the palate and 15% in the buccal area. In most treatment plans, retained canines are driven to extrusion through orthodontic treatment. However, in some cases, for technical reasons or patient choice, it is not possible to perform this consolidated approach. The present clinical report evaluates 10 ectopic canines transplanted in both adults and younger patients with up to 60 months of follow-up. Case description: Two clinical cases are described in detail with accompanying photographs and radiographs. In both of these cases, the retained canine was extracted, the receiving site prepared, a proper socket adapted through the use of implant osteotomy burs, and the canine transplanted into its ideal position. The tooth was fixed to the adjacent teeth for a variable period and healing was uneventful. After 60 months (Case 1) and 24 months (Case 2) of follow-up, the teeth did not show any color variation, the vitality tests were positive, and no signs of periapical reactions were detected. Practical implications: The transplantation of included canines, even with a formed apex, seems to be a successful procedure, although it should be reserved for those cases where an orthodontic approach is not viable. This procedure is able to provide a natural tooth with proprioceptive function, capable of accompanying the natural growth of the patient's jaws, with consequent eruption together with the adjacent teeth
Large melt diversity at a mid-ocean ridge thermal low
Get PDFMid-ocean ridges serve as key sites for understanding the composition of the mantle, but extensive melting usually masks its lithological diversity. This study explores how cold mid-ocean ridge segments, such as the eastern Romanche ridge-transform intersection (ERRTI), provide unique insights into mantle heterogeneity. Here, a thick cold lithosphere faces the warm ridge segment efficiently cooling the ridge tip, thus reducing melting and mixing, and allowing distinct short-scale lithologies to be sampled. Our findings reveal a mosaic of mantle components with diverse geochemical and isotopic signatures, reflecting dynamic mantle processes over time. By examining these cold regimes, this research sheds light on the mantle’s compositional complexity and its evolution, offering a fresh perspective on lithospheric dynamics and melt generation in settings independent of hotspot influences
Multifaceted superoxide dismutase 1 expression in amyotrophic lateral sclerosis patients: a rare occurrence?
Get PDFAmyotrophic lateral sclerosis (ALS) is a neuromuscular condition resulting from the progressive degeneration of motor neurons in the cortex, brainstem, and spinal cord. While the typical clinical phenotype of ALS involves both upper and lower motor neurons, human and animal studies over the years have highlighted the potential spread to other motor and non-motor regions, expanding the phenotype of ALS. Although superoxide dismutase 1 (SOD1) mutations represent a minority of ALS cases, the SOD1 gene remains a milestone in ALS research as it represents the first genetic target for personalized therapies. Despite numerous single case reports or case series exhibiting extramotor symptoms in patients with ALS mutations in SOD1 (SOD1-ALS), no studies have comprehensively explored the full spectrum of extramotor neurological manifestations in this subpopulation. In this narrative review, we analyze and discuss the available literature on extrapyramidal and non-motor features during SOD1-ALS. The multifaceted expression of SOD1 could deepen our understanding of the pathogenic mechanisms, pointing towards a multidisciplinary approach for affected patients in light of new therapeutic strategies for SOD1-ALS
Dermoscopy and reflectance confocal microscopy of solitary flat pink lesions: A new combined score to diagnose amelanotic melanoma
Get PDFBackgroundDifferential diagnosis of amelanotic/hypomelanotic melanoma among solitary flat pink lesions is challenging, due to limited clinical and dermoscopic clues. Dermoscopy and reflectance confocal microscopy assessments improve diagnostic accuracy, but their combined capacity among solitary flat pink lesions is yet to be defined.ObjectivesTo determine (i) whether diagnostic accuracy is improved with combined dermoscopy and reflectance confocal microscopy, (ii) a model to estimate probability of flat amelanotic/hypomelanotic melanoma among solitary flat pink lesions.MethodsA retrospective single-centre study of solitary flat pink lesions, excised for suspected malignancy between 2011 and 2022 was performed. Images were independently evaluated by two dermatologists, blinded to histopathological diagnosis. Diagnostic performance was evaluated on the receiver operating characteristic curve and the area under the curve. Predictive features were identified by univariate and multivariate logistic regression analyses. A final predictive nomogram of independent risk factors was calculated by backward likelihood ratio. Hypothesis being tested was formulated before data collection.ResultsA total of 184 patients (87 females, 47.3%) were included; mean age was 57.6 years (19-95). Combined dermoscopy and reflectance confocal microscopy was more sensitive (83%, CI 69.2-92.4 and 91.5%, CI 79.6-97.6) than dermoscopy alone (76.6%, CI 62.0-87.7 and 85.1%, CI 71.7-93.8). Predictive features defined the new model, including linear irregular vessels (4.26-folds, CI 1.5-12.1), peripheral pigment network (6.07-folds, CI 1.83-20.15), remnants of pigmentation (4.3-folds, CI 1.27-14.55) at dermoscopy and atypical honeycomb (9.98-folds, CI 1.91-51.96), disarranged epidermal pattern (15.22-folds, CI 2.18-106.23), dendritic pagetoid cells in the epidermis (3.77-folds, CI 1.25-11.26), hypopigmented pagetoid cells (27.05-folds, CI 1.57-465.5), and dense and sparse nests (3.68-folds, CI 1.24-10.96) in reflectance confocal microscopy. Diagnostic accuracy of the model was high (AUC 0.91).ConclusionsAdjunctive reflectance confocal microscopy increases diagnostic sensitivity of flat amelanotic/hypomelanotic melanoma differential diagnosis. The proposed model requires validation