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Le sparizioni forzate in Perù e le conseguenze di una questione irrisolta
No full textLe sparizioni forzate in Perù sono sempre state praticate da soggetti non statali, secondo i risultati della CVR, Comisión Verdad y Reconciliación del Perù. I tratti fondamentali delle sparizioni forzate in Perù sono: azioni sistematicamente compiute da gruppi insurrezionali in zone rurali; nei confronti popolazioni con una scarsa conoscenza dei propri diritti e della lingua ufficiale; stesso sistema adottato dalla spartizioni compiute da esercito e forze di polizia. In Perù, a 25 anni dalla fine del conflitto interno, a parte alcune azioni specifiche, non è stata adottata una politica sul tema, tanto che la Corte Interamericana dei diritti umani ha stabilito la responsabilità dello Stato peruviano e imposto misure di riparazione per i famigliari delle vittime.Enforced disappearances in Peru have always been practiced by non-state actors, according to the findings of the CVR (Truth and Reconciliation Commission of Peru). The key features of enforced disappearances in Peru are: systematic actions carried out by insurgent groups in rural areas; targeting populations with little knowledge of their rights and the official language. The same system was adopted by the military and police forces. In Peru, 25 years after the end of the internal conflict, aside from a few specific actions, no policy has been adopted on the issue, so much so that the Inter-American Court of Human Rights has established the responsibility of the Peruvian state and imposed reparation measures for the families of the victims
The depth-to-surface dynamics of silicic peralkaline magmas from Pantelleria Island
No full textSilicic peralkaline magmas are characterized by unusually low viscosity and responsible for a wide spectrum of eruptive styles, ranging from effusive to highly explosive Plinian eruptions. This apparent paradox challenges classical models of magma fragmentation and eruption dynamics. This thesis investigates the physical and chemical processes controlling magma ascent, degassing, fragmentation dynamics and eruptive behaviour in peralkaline silicic systems, using Pantelleria Island (Italy) as a natural laboratory. The study integrates textural analyses of juvenile products, anhydrous glass viscosity measurements, Raman spectroscopy, melt inclusion analyses and simultaneous thermal and evolved gas analyses (STA-EGA-MS) on products from four eruptions with similar bulk compositions but different eruptive styles: Cinque Denti (caldera-formingeruption), Green Tuff (caldera-forming-eruption), Zinedi (Sub-Plinian eruption) and Cuddia Mida (low-energy-Strombolian eruption). Integrated laboratory analyses are further used to perform numerical simulation of conduit dynamics. The results show that variations in eruptive style are primarily controlled by differences in ascent dynamics, volatile content and conduit geometry rather than bulk composition alone. Despite their low viscosities, peralkaline magmas can fragment due to their high water content concentration. Overall, this work provides new constraints on the mechanisms governing fragmentation and eruption dynamics of peralkaline magmas and contributes to improving rheological models for these compositions, with implications for volcanic hazard assessment in peralkaline volcanic region
Study of innovative therapies for multiple sclerosis
No full textIn recent years, nanotechnologies have acquired an increasingly important role in the development of innovative therapeutic strategies, particularly in the field of drug delivery. The interaction between nanomaterials and the immune system is an area of great interest, as it allows not only to improve the efficacy of drugs, but also to selectively modulate immune responses. In this context, the main objective of this doctoral thesis was the development and characterisation of biocompatible gold and silver nanoparticles capable of selectively interacting with specific cells of the immune system and being exploited as delivery systems for drugs with immunomodulatory and anti-inflammatory activity. The work focused on the synthesis of gold and silver nanoparticles stabilised with different surface ligands such as citrate, L-cysteine and polyethylene glycol (PEG), chosen for their known colloidal stabilisation properties and biocompatibility. The first phase of the study was dedicated to optimising the synthesis protocols in order to obtain reproducible nanoparticle systems that are stable over time and characterised by controlled chemical-physical properties. The optimisation of the experimental conditions made it possible to modulate key parameters such as size, size distribution, aggregation state and colloidal stability, which are fundamental aspects for subsequent biological use. The chemical-physical characterisation of the nanoparticles was conducted using an integrated approach that included spectroscopic techniques, size and polydispersity analysis, colloidal stability assessments, and surface interaction studies. Systematic comparison of the different formulations showed that the nature of the stabilising ligand significantly influences the properties of the nanoparticles, determining not only their physical characteristics but also their ability to interact with functionalising molecules. The overall analysis of the data allowed the selection of the most promising formulations, in particular gold nanoparticles stabilised with citrate and L-cysteine (Au-CitCys), for subsequent biological evaluations. The selected nanoparticles underwent biocompatibility studies, which demonstrated an adequate safety profile under the experimental conditions adopted. These results allowed for further study of the interactions between nanoparticles and human immune system cells, using peripheral blood mononuclear cells (PBMCs) as an experimental model. The functionalisation of nanoparticles with fluorescent probes was a fundamental tool for monitoring their association with cells and identifying the cell subpopulations most involved in the interaction. The results obtained showed that nanoparticles have an intrinsic ability to interact selectively with specific cells of the immune system. This evidence provided the rationale for the development of a “Trojan horse” drug delivery strategy, in which nanoparticles are used as vectors to facilitate the transport and action of an immunomodulatory and anti-inflammatory drug within the immune system. The functionalisation of the drug on nanoparticles has made it possible to evaluate the efficacy of the delivery system compared to the free drug. The biological data collected show that the drug delivered by nanoparticles exhibits significantly enhanced activity in modulating the immune response. In particular, the nanoparticle system is able to steer the response towards a more tolerogenic and anti-inflammatory profile, a therapeutic goal of primary importance in the treatment of diseases characterised by chronic inflammation and immune dysregulation, such as multiple sclerosis. Overall, this work demonstrates that the nanoparticles developed are not only biocompatible and capable of selectively interacting with immune system cells, but can also be effectively exploited as drug delivery systems to improve the efficacy of immunomodulatory drugs. In particular, Au-CitCys nanoparticles emerge as promising platforms for future applications in the field of immunological nanomedicine. The results obtained provide a solid basis for further preclinical studies and open up new perspectives for the development of innovative therapeutic strategies based on nanomaterials, aimed at the targeted treatment of inflammatory and immune-mediated diseases
A Study into Aspect Ratio and the Influence of Platen Restraint on the Compressive Strength of Jute Fibre-Reinforced Compressed Earth Composites
No full textThis study investigates the behaviour of Compressed Earth Cylinders (CECs) and Compressed Earth Blocks (CEBs) during direct compression tests and examines the influence of aspect ratio and the effects of platen restraint. The experimental investigation utilises two soil types and examines the impact of jute fibre reinforcement on the failure mechanism of CECs with aspect ratios ranging from 0.50 to 2.00. Through experimental analysis and numerical modelling, the effects of platen restraint are examined, and a novel hypothesis of intersecting cones is presented. The results show that specimens with a lower aspect ratio exhibited higher compressive strength due to confinement caused by platen restraint. Moreover, this research has derived new aspect ratio correction factors that enable conversion from Apparent Compressive Strength (ACS) to Unconfined Compressive Strength (UCS) of unstabilised and fibre-reinforced CECs. The experimental results indicate that the derived conversion factor of 0.861 allows for the prediction of CEB strength from CEC specimens with an accuracy of 2.7%. Furthermore, the addition of jute fibres at a 0.25% dosage increased the Apparent Compressive Strength across all aspect ratios. The outcome of this research recommends a standard approach to the application of aspect ratio correction factors when interpreting and reporting the compressive strength of CECs and CEBs
Pseudomonas aeruginosa DEV phage exploits the essential LptD outer membrane protein as receptor for adsorption
No full textPseudomonas aeruginosa bacteriophage (phage) DEV is a podovirus of the Schitoviridae family, related to the prototypical Escherichia coli phage N4. N4 uses the novel glycan receptor (NGR) surface glycan, presumably bound by the gp66 appendages, and the NGR transporter NfrA, recognized by the phage gp65 tail sheath, as receptors for adsorption. In contrast, DEV relies on the O-antigen moiety of lipopolysaccharide (LPS) as the primary receptor recognized by the gp53 long tail fibers. However, DEV can infect deep-rough strains that lack the O-antigen moiety by using another, still unknown receptor. Here, we provide evidence that the essential LPS transporter LptD serves as the DEV secondary receptor and that DEV gp54 is its cognate receptor-binding protein. gp54 is encoded within the essential gp56-gp55-gp54 operon, which also includes gp56, the short tail fiber gene. Using cryogenic electron microscopy, AlphaFold modeling, and genetic analysis, we show that DEV gp56, gp55, and gp54 assemble into a receptor-binding fiber (RBF) positioned laterally to a previously uncharacterized tail plug protein, gp74. The DEV RBF is functionally equivalent to the N4 sheath protein gp65, which associates with the tail plug gp53. Thus, DEV and N4 both use a glycan and its surface-exposing transporter as receptors for adsorption. To our knowledge, this is the first example of a P. aeruginosa phage using an essential outer membrane protein as a receptor, with implications for phage therapy.IMPORTANCEPseudomonas aeruginosa phage DEV uses the O-antigen of lipopolysaccharide as its primary receptor. In this study, we found that LptD, an essential and highly conserved outer membrane protein, serves as the secondary receptor for DEV. This interaction is mediated by a specialized receptor-binding fiber composed of the DEV proteins gp54, gp55, and gp56. We posit that the gp56-gp55-gp54 genes form a functional module, possibly disseminated via horizontal gene transfer among distantly related phages, involved in tail sealing and the regulated unplugging of the tail upon interaction with the bacterial receptor. Given the high conservation of receptor-binding proteins among phages in the DEV Litunavirus genus, we anticipate that other members of this genus may also use LptD as their receptor. Since Litunaviruses are actively explored for phage therapy, insights into the interaction between DEV and its receptors could help develop more effective and targeted phage-based treatments
Innovative approaches for the structural maintenance of Italian heritage in Reinforced Concrete. Development of a methodology for structural diagnosis and monitoring
No full textNegli ultimi decenni, opere strutturali ed infrastrutturali realizzate in calcestruzzo armato hanno spesso mostrato evidenti e prematuri segni di degrado, a danno dell’integrità strutturale. Non di minor importanza, prematuri cedimenti e crolli hanno interessato differenti opere civili, causando danni ingenti alla popolazione, in termini di mortalità, operabilità strutturale ed infrastrutturale ed economici. La manutenzione ordinaria risulta un importante e fondamentale mezzo di prevenzione del degrado; tuttavia, quando quest’ultima manca o non rispetta le necessità di intervento dell’opera, il metodo di prevenzione diviene inefficace. Lo Structural Health Monitoring (SHM) mediante monitoraggio periodico e continuo di parametri statici e dinamici, insieme con metodi di indagine non distruttiva (NDT) si coniugano al fine di convergere ad una conoscenza integrata ed integrale dello stato strutturale e la conseguente prescrizione di manutenzione ordinaria “ad hoc”. A tal proposito, il presente studio di ricerca nell’ambito del corso di dottorato, mira a valutare la salute strutturale di edifici ed infrastrutture esistenti in c.a. impiegando nuove tecnologie nel rilevamento di difetti e criticità strutturali, locali e globali, presumendo di proporre una metodologia innovativa. In particolare, in prima battuta si approfondisce lo stato dell’arte di metodi e tecnologie impiegate tradizionalmente per il SHM e l’indagine non distruttiva, nell’ambito del degrado del patrimonio in calcestruzzo armato. A tal proposito, si approfondisce la nuova tecnologia in fibra ottica di sensori quasidistribuiti Fiber Bragg Grating, mediante prove di laboratorio per la conoscenza della stessa e la valutazione delle potenzialità. Ne consegue l’applicazione per un monitoraggio continuativo su un caso studio appartenente al patrimonio italiano in c.a., edificio alto di particolare complessità, unico nella soluzione architettonica ed ingegneristica. Il fine è di fornire una metodologia critica per il progetto, la manutenzione ed il controllo del setup e dell’elaborazione per l’interpretazione e validazione dei dati acquisiti, provenienti da sensori che monitorano grandezze ambientali e strutturali, con l’obiettivo di fornire una visione completa di vantaggi e deficit della tecnologia e, nel dettaglio, della applicazione. Per ciò che concerne le criticità ed i difetti che interessano il patrimonio in c.a., prima localmente e poi nella performance strutturale, in tale sede, si impiegano tecniche di natura elettrochimica per l’indagine non distruttiva, avendo individuato un caso studio di notevole interesse, tra le infrastrutture che appartengono all’architettura della città di Roma. L’obiettivo è di acquisire misure in situ e, tramite l’interpretazione delle stesse, di contribuire ad un modello previsionale utile alla stima dei tempi di intervento, tenendo conto di condizioni osservate qualitativamente e quantitativamente.In recent decades, the Reinforced Concrete heritage, constituted of buildings and infrastructures, have frequently exhibited evident and premature signs of degradation, compromising the structural integrity. Nevertheless, premature failures and collapses have affected the civil engineering landscape, causing significant damage to the population in terms of mortality, structural and infrastructural operability, and economic losses. Ordinary maintenance plays a crucial and fundamental role in preventing deterioration; however, in its absence or inappropriate with structural needs, its function becomes ineffective. Structural Health Monitoring (SHM), through periodic and continuous monitoring of static and dynamic parameters, combined with Non-Destructive Testing (NDT) methods, aims to achieve a comprehensive and integrated understanding of structural conditions, enabling the prescription of tailored maintenance strategies. In this regard, the present doctoral research study aims to assess the structural health of existing Reinforced Concrete (RC) buildings and infrastructures by employing innovative technologies for detecting local and global defects and vulnerabilities, with the prospect of proposing a novel methodological approach. Specifically, the first phase of the study reviews the state of the art of traditional methods and techniques for SHM and NDT, in the context of RC degradation. Special attention is given to emerging optical fibre-based sensing technologies, with a major focus on quasi-distributed Fiber Bragg Grating (FBG) sensors. Laboratory experiments are conducted to enhance knowledge of this technology and assess its potential, followed by its application in continuous monitoring of a case study: a tall RC building of notable architectural and engineering complexity. The objective is to establish a critical methodology for design, maintenance, and monitoring, as well as for setup control, storage, data processing, and interpretation. The data acquired from sensors, measuring environmental parameters and structural parameters are analysed to provide a comprehensive evaluation of the advantages and limitations of technologies, with a specific focus on the application on-field. Also, as concerns the criticalities affecting RC heritage in local and global performance, electro-chemical NDT are used for the investigation of corrosive defect. Among the architectural heritage of Rome, a RC bridge of considerable interest is analysed. Starting from experimental campaigns for the collection of electro-chemical measures, a statistically based interpretation is proposed, accounting for both qualitative and quantitative observations of the structure’s condition and contributing to the estimation of intervention timelines