Mechanochemistry: Versatile and Functional Strategy for the Realization and the Recycling of Multi-Phase Materials

La presente tesi di dottorato è incentrata sullo sviluppo di metodologie sostenibili per la modifica, la produzione ed il riciclo di materiali organici, concentrandosi su due classi di materiali:1) poliolefine e 2)biomasse cellulosiche e lignocellulosiche. L'obiettivo è aumentare la sostenibilità dei processi aderendo ai principi della Green Chemistry, attraverso la progettazione di strategie che riducano l'uso di sostanze chimiche e solventi, evitino la generazione di rifiuti, consentano l'utilizzo di materie prime rinnovabili, promuovano la biodegradabilità. Nello specifico, in questa tesi, sono stati sviluppati processi meccanochimici mediante l'utilizzo di un mulino a sfere planetario (ball milling, BM). Questo tipo di trattamenti si basa sull'applicazione di forze di taglio e compressione su materiali solidi attraverso l'azione di sfere orbitanti, al fine di indurre cambiamenti morfologici e strutturali e, in alcuni casi, modifiche chimiche nei materiali organici. Sono stati seguiti diversi approcci, per dimostrare la versatilità dei trattamenti meccanochimici per la realizzazione di diversi materiali. In un primo approccio (II capitolo), viene riportato uno studio approfondito sull'effetto dei trattamenti meccanochimici sul polipropilene (PP), uno dei polimeri più diffusi, per valutare sistematicamente gli effetti dei processi meccanochimici sul polimero. Lo scopo di questo studio è stato quello di esplorare la possibilità di indurre reazioni radicaliche nel PP e in miscele a base di PP attraverso processi meccanochimici allo stato solido, sia per promuovere la formazione di ramificazioni di catena e/o per ottenere l'innesto di diverse molecole. I campioni di PP trattati sono stati analizzati attraverso varie tecniche di caratterizzazione. In particolare, l'analisi in chemiluminescenza ha rivelato la formazione di specie reattive, generate da reazioni radicaliche, particolarmente numerose per trattamenti di BM lunghi. Per fornire un proof of concept del potenziale utilizzo dei radicali prodotti per modificare chimicamente il PP, i trattamenti di BM sono stati eseguiti in presenza di sostanze chimiche sensibili alle reazioni radicaliche, polibutadiene a basso PM (BR) e glicidil metacrilato (GMA). Dopo la reazione e la purificazione, l'analisi spettroscopica ha dato evidenza dell'innesto di una piccola quantità sia di GMA che di BR su PP.Nel III capitolo, il BM è stato sfruttato come strumento per valorizzare e riciclare rifiuti plastici eterogenei ricchi di poliolefine. In particolare, i trattamenti meccanochimici sono stati eseguiti su una frazione di film di piccole dimensioni recuperata dalla raccolta dei rifiuti domestici, per indagare gli effetti indotti dalle intense sollecitazioni meccaniche sulla morfologia e sulle proprietà dei materiali trattati. Per quanto riguarda la valorizzazione della cellulosa e delle biomasse, sono state svolte due principali attività di ricerca:In un primo studio, nel IV capitolo, sono stati realizzati compositi a base di acido poli(lattico) (PLA) contenenti materiali cellulosici come filler organico e un estere oligomerico dell'acido lattico come agente plasticizzante, al fine di migliorare e modulare le caratteristiche meccaniche e termiche di questo polimero biodegradabile. Il processo di BM è stato utilizzato in diverse condizioni come processo sostenibile e flessibile per indurre cambiamenti strutturali e morfologici nella cellulosa, prima della realizzazione del composito. Infine, nel V capitolo, viene riportato lo sviluppo di un coating completamente bio-based a base di coffee silverskin (CS), un sottoprodotto del processo di tostatura del caffè, mediante trattamento meccanochimico. Il trattamento di BM è stato proposto per la destrutturazione della struttura complessa del CS, in condizioni blande ed utilizzando solo acqua come solvente.The present doctoral thesis deals with the development of “greener” methodologies for the modification, the production and the recycling of organic materials, focusing on two classes of materials:1)polyolefins and 2) cellulose and ligno-cellulosic biomasses.The aim is to increase the sustainability of processes adhering to the principles of Green Chemistry, through the design of strategies that reduce the use of chemicals and solvents, avoid waste generation by extending recycling, enable the utilization of renewable raw materials, promote biodegradability.Specifically, in this thesis, mechanochemical processes were developed through the use of a ball-milling apparatus. This kind of treatments relies on the application of intense shear and compressive forces to solid materials through the action of the milling bodies, in order to induce morphological and structural changes and, in some cases, chemical modifications in organic materials. Different approaches were followed, to demonstrate the versatility of mechanochemical treatments for the realization of different materials. In a first approach (II chapter), an in-depth study on the effect mechanochemical treatments on polypropylene (PP), one of the most diffused commodity polymer, is reported to systematically evaluate the effects of mechanochemical processes on polymers. The aim of this study was to explore the possibility to induce radical reactions in PP and PP based mixtures through solid state mechanochemical processes, to either promote the formation of chain branching and/or to obtain the grafting of different molecules.Treated PP samples were analyzed through various characterization techniques. In particular, chemiluminescence analysis revealed the formation of reactive species, generated by radical reactions, especially abundant for long BM treatments.To provide a proof of concept of the exploitability of the produced radicals to chemically modify PP, BM treatments were performed in presence of chemicals susceptible to radical reactions, low MW polybutadiene (BR) and glycidyl methacrylate (GMA). After reaction, and purification, spectroscopic analysis gave evidence of the grafting of a small amount of both GMA and BR onto PP. In the III chapter, BM was exploited as a tool to valorize and recycle polyolefin rich heterogeneous plastic waste. In particular, the mechanochemical treatments were performed on a small-sized film fraction recovered from household waste collection, to investigate the effects induced by the intense mechanical stresses on morphology and properties. Regarding the valorization of cellulose and biomasses, two main research activities were carried out: in a first study, in the IV chapter, poly(lactic) acid (PLA)-based composites containing cellulosic materials as an organic filler and an oligomeric ester of lactic acid as a plasticizing agent were realized, in order to improve and modulate thermal and mechanical response of this biodegradable polymer. Ball milling was used in different conditions as a green, flexible process to induce structural and morphological changes in cellulose, before composite realization. Finally, in the V chapter, the development of a fully bio-based coating based on coffee silverskin (CS), a coffee roasting process by-products, by mechano-chemical treatment is reported. The BM treatment has been proposed for the deconstruction of the complex structure of CS, in mild conditions and using only water as solvent

Using ground motion prediction equations to monitor variations in quality factor due to induced seismicity: a feasibility study

Sub-surface operations for energy production such as gas storage, fluid reinjection or hydraulic fracking may modify the physical properties of the rocks, in particular the seismic velocity and the anelastic attenuation. The aim of the present study is to investigate, through a synthetic test, the possibility of using empirical ground-motion prediction equations (GMPEs) to observe the variations in the reservoir. In the synthetic test, we reproduce the expected seismic activity (in terms of rate, focal mechanisms, stress drop and the b value of the Gutenberg-Richter) and the variation of medium properties in terms of the quality factor Q induced by a fluid injection experiment. In practice, peak-ground velocity data of the simulated earthquakes during the field operations are used to update the coefficients of a reference GMPE in order to test whether the coefficients are able to capture the medium properties variation. The results of the test show that the coefficients of the GMPE vary during the simulated field operations revealing their sensitivity to the variation of the anelastic attenuation. The proposed approach is suggested as a promising tool that, if confirmed by real data analysis, could be used for monitoring and interpreting induced seismicity in addition to more conventional techniques

Effects of physical activity on endothelial progenitor cells (EPCs)

Physical activity has a therapeutic role in cardiovascular disease (CVD), through its beneficial effects on endothelial function and cardiovascular system. Circulating endothelial progenitor cells (EPCs) are bone marrow (BM) derived cells that represent a novel therapeutic target in CVD patients, because of their ability to home to sites of ischemic injury and repair the damaged vessels. Several studies show that physical activity results in a significant increase in circulating EPCs, and, in particular, there are some evidence of the beneficial exercise-induced effects on EPCs activity in CVD settings, including coronary artery disease (CAD), heart failure (HF), and peripheral artery disease (PAD). The aim of this paper is to review the current evidence about the beneficial effects of physical exercise on endothelial function and EPCs levels and activity in both healthy subjects and patients with CVD

High-fat diet impairs duodenal barrier function and elicits glia-dependent changes along the gut-brain axis that are required for anxiogenic and depressive-like behaviors

Background: Mood and metabolic disorders are interrelated and may share common pathological processes. Autonomic neurons link the brain with the gastrointestinal tract and constitute a likely pathway for peripheral metabolic challenges to affect behaviors controlled by the brain. The activities of neurons along these pathways are regulated by glia, which exhibit phenotypic shifts in response to changes in their microenvironment. How glial changes might contribute to the behavioral effects of consuming a high-fat diet (HFD) is uncertain. Here, we tested the hypothesis that anxiogenic and depressive-like behaviors driven by consuming a HFD involve compromised duodenal barrier integrity and subsequent phenotypic changes to glia and neurons along the gut-brain axis. Methods: C57Bl/6 male mice were exposed to a standard diet or HFD for 20 weeks. Bodyweight was monitored weekly and correlated with mucosa histological damage and duodenal expression of tight junction proteins ZO-1 and occludin at 0, 6, and 20 weeks. The expression of GFAP, TLR-4, BDNF, and DCX were investigated in duodenal myenteric plexus, nodose ganglia, and dentate gyrus of the hippocampus at the same time points. Dendritic spine number was measured in cultured neurons isolated from duodenal myenteric plexuses and hippocampi at weeks 0, 6, and 20. Depressive and anxiety behaviors were also assessed by tail suspension, forced swimming, and open field tests. Results: HFD mice exhibited duodenal mucosa damage with marked infiltration of immune cells and decreased expression of ZO-1 and occludin that coincided with increasing body weight. Glial expression of GFAP and TLR4 increased in parallel in the duodenal myenteric plexuses, nodose ganglia, and hippocampus in a time-dependent manner. Glial changes were associated with a progressive decrease in BDNF, and DCX expression, fewer neuronal dendritic spines, and anxiogenic/depressive symptoms in HFD-treated mice. Fluorocitrate (FC), a glial metabolic poison, abolished these effects both in the enteric and central nervous systems and prevented behavioral alterations at week 20. Conclusions: HFD impairs duodenal barrier integrity and produces behavioral changes consistent with depressive and anxiety phenotypes. HFD-driven changes in both peripheral and central nervous systems are glial-dependent, suggesting a potential glial role in the alteration of the gut-brain signaling that occurs during metabolic disorders and psychiatric co-morbidity

Quality of care provided by Multiple Sclerosis Centers during Covid-19 pandemic: Results of an Italian multicenter patient-centered survey

Background: Covid-19 pandemic impacted on management of people with Multiple Sclerosis (pwMS). Level of satisfaction of pwMS regarding the care received by the staff of Multiple Sclerosis Centers (MSCs) during the pandemic was not fully investigated. In a large patient-centered multicenter study, the therapeutic adherence and quality of care of MSCs was assessed. Methods: In April-May 2021, an online survey was widespread by 16 Italian MSCs. Frequencies, percentages and/or means and standard deviations were calculated to describe the sample. ANOVAs were performed to evaluate the effect of sociodemographic and clinical variables on overall pwMS' rating of MSC assistance. Results: 1670 pwMS completed the survey (67.3% women). During the pandemic, 88% did not change their disease modifying therapy schedule, and 89.1% reached their MSCs with no or little difficulties. Even if only 1.3% of participants underwent a tele-health follow-up visit with their MSC staff, the 80.1% believed that tele-health services should be improved regardless of pandemic. 92% of participants were satisfied of how their MSC took charge of their needs; ANOVAs revealed an effect of disease duration on pwMS' level of satisfaction on MSCs management during the pandemic. Conclusions: The results revealed an efficient MSCs response to Covid-19 pandemic and provided the basis for the implementing of tele-health services that would further improve the taking charge of patients, particularly those with longer disease, higher disability, and/or living far from their MSC

Multicentre harmonisation of a six-colour flow cytometry panel for naïve/memory T cell immunomonitoring

Background. Personalised medicine in oncology needs standardised immunological assays. Flow cytometry (FCM) methods represent an essential tool for immunomonitoring, and their harmonisation is crucial to obtain comparable data in multicentre clinical trials. The objective of this study was to design a harmonisation workflow able to address the most effective issues contributing to intra- and interoperator variabilities in a multicentre project. Methods. The Italian National Institute of Health (Istituto Superiore di Sanita, ISS) managed a multiparametric flow cytometric panel harmonisation among thirteen operators belonging to five clinical and research centres of Lazio region (Italy). The panel was based on a backbone mixture of dried antibodies (anti-CD3, anti-CD4, anti-CD8, anti-CD45RA, and anti-CCR7) to detect naive/memory T cells, recognised as potential prognostic/predictive immunological biomarkers in cancer immunotherapies. The coordinating centre distributed frozen peripheral blood mononuclear cells (PBMCs) and fresh whole blood (WB) samples from healthy donors, reagents, and Standard Operating Procedures (SOPs) to participants who performed experiments by their own equipment, in order to mimic a real-life scenario. Operators returned raw and locally analysed data to ISS for central analysis and statistical elaboration. Results. Harmonised and reproducible results were obtained by sharing experimental set-up and procedures along with centralising data analysis, leading to a reduction of cross-centre variability for naive/memory subset frequencies particularly in the whole blood setting. Conclusion. Our experimental and analytical working process proved to be suitable for the harmonisation of FCM assays in a multicentre setting, where high-quality data are required to evaluate potential immunological markers, which may contribute to select better therapeutic options

Cardiopulmonary determinants of reduced exercise tolerance in Fabry disease

Fabry disease (FD), also known as Anderson-Fabry disease, is a hereditary disorder of glycosphingolipid metabolism, caused by a deficiency of the lysosomal alpha-galactosidase A enzyme. This causes a progressive accumulation of glycosphingolipids in tissues and organs which represents the main pathogenetic mechanism of FD. The disease is progressive and multisystemic and is characterized by early symptoms and late complications (renal, cardiac and neurological dysfunction). Fatigue and exercise intolerance are early common symptoms in FD patients but the specific causes are still to be defined. In this narrative review, we deal with the contribution of cardiac and pulmonary dysfunctions in determining fatigue and exercise intolerance in FD patients

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia