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Synthesis and Characterization of Calcium Phosphate Powders for Biomedical Applications by Plasma Spray Coating
No full textThis PhD work mainly focus on the synthesis and characterization of calcium phosphate powders for plasma spray coating. The preparation of high temperature phase stabilized βTCP and HA/βTCP powders for plasma spray coating applications has been the topic of investigation. Nowadays plasma sprayed coatings are widely used for biomedical applications especially in the dental and orthopaedic implantation field. Previously Ti based alloys were widely used for the orthopaedic and dental implant applications because of its high corrosion and good biocompatibility. Due to the limited osteoconductivity edges of Ti implants with fibrous tissues delays the healing time. To overcome these limitations different types of surface modification processes are employed on the surface of Ti. The coating of HA is a widely used surface modification technique due to its excellent biological properties. HA is a well employed bone graft material due to its similarity with human hard tissues. The plasma spraying of HA on the Ti surface is the most widely used technique mainly due to its process simplicity, low cost and bulk production.
The present research focuses on the modification of HA coatings for the improvement of bio-degradation properties of HA. HA/βTCP composite powders are used to overcome the poor biodegradation properties of HA. The issue related to the use of βTCP is the phase transformation (β to α) at high temperature. To overcome this phase transformation, the βTCP powder was doped with MgO. The high temperature phase stabilized MgO doped βTCP and HA/βTCP powders were synthesized by solid state method and granulated using spray granulation. The properties of the granulated powders (100-150μm) were analysed with XRD, FT-IR, SEM, flowabilty, density etc. and are used in plasma spray coating process. The produced coatings were subjected to the thermal treatment and βTCP and HA/βTCP plasma sprayed coatings are obtained. The successively produced coatings were characterized, and the invitro properties like solubility and bioactivity behaviours were studied
Il nemico ritrovato. Carl Schmitt e gli Stati Uniti
No full textLa tesi affronta il tema del rapporto tra Carl Schmitt e gli Stati Uniti. Il primo capitolo, dedicato all'America vista da Schmitt, ripercorre i riferimenti presenti nell'opera dell'autore – dall'interpretazione della tradizione politico-giuridica americana in opposizione a quella continentale, al ruolo determinante che ha il Nuovo Mondo nello sviluppo e nella decadenza dell'ordinamento internazionale moderno, fino alle suggestioni teologico-politiche legate alla figura del katéchon – giungendo alla conclusione che non si possa liquidare l'atteggiamento di Schmitt come una pura e semplice ostilità assoluta nei confronti dell'America e di ciò che rappresenta. Per rendere conto di questo rapporto in tutta la sua complessità, occorre tenere presente la costitutiva ambivalenza dell'ultimo concetto schmittiano di inimicizia, e il suo implicare la dimensione del riconoscimento.
Il secondo capitolo tratta del rapporto fra Schmitt e il nutrito gruppo dei suoi ex-allievi ed ex-amici che lasciarono la Germania per gli Stati Uniti a partire dagli anni Trenta. Al di là delle curiosità storico-biografiche, la ricostruzione di queste relazioni scientifiche e professionali e del loro retaggio è determinante per comprendere la (mancata) ricezione dell'opera di Schmitt nel secondo dopoguerra, e permette di fare un bilancio critico dell'ipotesi che egli abbia esercitato un'influenza “sotterranea” sul conservatorismo americano (ipotesi che nella tesi viene decisamente respinta per carenza di basi filologiche). Il terzo capitolo indaga la ricezione del pensiero schmittiano da parte di Hannah Arendt, prendendo spunto dalle moltissime annotazioni manoscritte lasciate da quest'ultima in margine alla sua copia del Nomos della terra. Insieme ai diari degli anni Cinquanta, questi appunti sono la traccia di un confronto molto significativo, che coincide (cronologicamente e concettualmente) con l'elaborazione della teoria dell'agire politico che troverà espressione nelle opere successive (Vita activa, Sulla rivoluzione, e l'incompiuta Introduzione alla politica): sebbene in questi scritti non sia mai citato il nome di Schmitt, la sua presenza come interlocutore implicito è pressoché costante, e testimoniata da un gran numero di indizi testuali. Nel quarto capitolo, infine, con una rassegna della bibliografia in lingua inglese degli ultimi trent'anni, si ricostruisce il crescente interesse per l'opera di Schmitt con particolare attenzione per due casi: quello della rivista «Telos», che ne ha rielaborato il pensiero integrandolo (non senza forzature) in una prospettiva di radicalismo democratico, e quello della leggenda storiografica che ha fatto di Schmitt una sorta di ispiratore occulto del neoconservatorismo americano e dell'amministrazione Bush junior
Rule-dependent and stimulus-dependent visuomotor mappings of otherâs actions
No full textMy thesis aims at demonstrating the existence of two parallel networks that are involved in stimulus-dependent and rule-dependent visuomotor associations.
In the first experiment we demonstrated a biphasic time-course of motor cortical excitability during a counter-imitative task: a stimulus-dependent automatic simulation at 150 ms from the stimulus onset and a rule-dependent voluntary motor preparation at 300 ms. Moreover we identified two regions involved in this biphasic pattern by means of the repetitive transcranial magnetic stimulation (rTMS). The double-dissociation between the effects of offline rTMS to the lateral prefrontal and parietal cortices, on the early and late components, allowed us to hypothesize the presence of two different anatomo-functional pathways: a parieto-(premotor) network mediating early stimulus-dependent responses and a (temporo)-prefrontal network producing late rule-dependent responses.
Thus, the first experiment adds important information on the mechanisms by which the brain is both tuned to produce imitative responses in a fast automatic way but is also capable of overriding them by means of a parallel, more flexible, visuomotor coupling that follows arbitrary visuomotor associations. The fast imitative tendencies seemingly persist also during the online performance of a counter-imitative task. The two processes access the motor output by two partially independent neural substrates.
We took a step forward in the second experiment where we investigated, by means of the combined rTMS and fMRI techniques, the functional connectivity in the rule-dependent executive pathway. We used the condition-and-map approach to highlight the brain regions where this pathway passes through to give a counter-imitative response. We hypothesised that this region could be the premotor cortex, and probably the dorsal part of it. Our data showed that exactly in the dorsal premotor cortex there is an interaction between the TMS stimulations and the tasks.
Taken together these results allowed us to add a new piece in the puzzle of the rule-dependent visuomotor pathway. The further step will be to use the same paradigm to test the stimulus-dependent automatic pathway and finally to test where these two systems converge either in the premotor cortex or in the motor cortex
Understanding Visual Information: from Unsupervised Discovery to Minimal Effort Domain Adaptation
No full textVisual data interpretation is a fascinating problem which has received an increasing attention in the last decades. Reasons for this growing trend can be found within multiple interconnected factors, such as the exponential growth of visual data (e.g. images and videos) availability, the consequent demand for an automatic way to interpret these data and the increase of computational power. In a supervised machine learning approach, a large effort within the research community has been devoted to the collection of training samples to be provided to the learning system, resulting in the generation of very large scale datasets. This has lead to remarkable performance advances in tasks such as scene recognition or object detection, however, at a considerable high cost in terms of human labeling effort. In light of the labeling cost issue, together with the dataset bias one, another significant research direction was headed towards developing methods for learning without or with a limited amount of training data, by leveraging instead on data properties like intrinsic redundancy, time constancy or commonalities shared among different domains. Our work is in line with this last type of approach. In particular, by covering different case scenarios - from dynamic crowded scenes to facial expression analysis - we propose a novel approach to overcome some of the state-of-the-art limitations. Based on the renowned bag of words (BoW) approach, we propose a novel method which achieves higher performances in tasks such as learning typical patterns of behaviors and anomalies discovery from complex scenes, by considering the similarity among visual words in the learning phase. We also show that including sparsity
constraints can help dealing with noise which is intrinsic to low level cues extracted from complex dynamic scenes. Facing the so called dataset bias issue, we propose a novel method for adapting a classifier to a new unseen target user without the need of acquiring additional labeled samples. We prove the effectiveness of this method in the context of facial expression analysis showing that our method achieves higher or comparable performance to the state of the art, at a drastically reduced time cost
The neurophysiology of internally-driven actions
No full textActing in the world in a way that matches our goals, overriding impulses, is one of the first abilities that we must learn while growing up. We often change the course of our actions because of external influences or because we simply “change our mind”. As John H. Patterson said, “Only fools and dead men don't change their minds. Fools
won’t. Dead men can’t”. An important distinction must first be made between the impact of internal and external sources on action decisions, and the first part of the
introduction will be devoted to this topic. In the second part, I will discuss the topic of inhibitory control. In the scientific literature, action inhibition is often treated as a unitary phenomenon, while the distinction among different types of inhibitions might explain the diverse results and be useful for future studies. My experimental work has
been devoted to both externally-triggered and internally-driven voluntary action inhibition, in particular, in Experiment 1 I conducted a set of studies aiming at
understanding the underlying cortical circuits for internally-driven action inhibition, whereas Experiment 2 focused on proactive inhibition mechanisms. While it is beyond the scope of this manuscript to cover the entire literature on inhibitory control, I would like to propose a common view to unify the different theories concerning how the brain exerts voluntary inhibitory control and provide some suggestions for future investigations to study the way we flexibly control our actions to cope with the
constantly changing external, and internal, environment
Le nullità degli atti processuali civili
No full textIl presente studio ha a oggetto il sistema giuridico che regola il fenomeno della divergenza di ogni attività processuale dall’archetipo legale di riferimento. L'argomento investe la questione pregiudiziale di metodo del processo, ne svela l’ossatura portante nel suo movimento serialmente dinamico, anticipa e prelude al problema contenutistico della fondatezza degli atti e della giusta composizione della lite. Se il processo è l’ordinamento mediante il quale lo Stato attua la concreta volontà di legge e i soggetti di diritto ricevono la tutela giurisdizionale delle situazioni giuridiche lese, la disciplina delle nullità non è niente di più che lo strumento col quale sindacare l’irritualità di questo fenomeno e, se possibile, ricondurlo entro i binari delle “regole del gioco”
A monitoring method for after-earthquake damage evaluation of buildings
No full textAfter-earthquake assessment of buildings in terms of usability and safety is nowadays performed by in-charge technicians which are called to give their judgment basing mainly on in-field surveys and visual inspections. This necessarily implies additional inconvenience for residents and economic losses in the affected area, being often large the time required for conducting the surveys and being the judgment on the safe side in absence of objective data. A near real-time assessment based on objective data related to the seismic response of the structures is possible though the use of a monitoring systems capable of providing information on the state of the monitored structure inferring observations of its dynamic response. One of the most reliable parameter which can be correlated to the state of condition of a structure after an earthquake is the ductility demand expressed in terms of interstory drift. The use in monitoring systems of this indicator is examined in this thesis through case studies on reinforced concrete framed buildings and precast industrial buildings. In the design process of the systems I proposed a capacity-demand approach, through the prior formal definition of the requirements of accuracy and the calculation of the actual accuracy of the designed monitoring system. In particular I investigated in detail the uncertainties, both instrumental and related to model, to be combined in order to obtain the overall uncertainty of the information provided by the monitoring system, when using the method of double integration of the acceleration measurements. I have found that in general the instrumental uncertainties have less importance to the uncertainties of the model, in particular in presence of residual displacements at the end of the seismic motion. Aiming to reduce uncertainties in the presence of residual displacements and to cancel the need of high-pass filtering acceleration signals, I proposed a sensing bar prototype instrumented with accelerometers and inclinometers
Management of Bridge infrastructural Networks in seismic Areas
No full textThis study deepens key issues related to the seismic emergency management and deterioration state assessment of roadway and railway infrastructural networks by proposing a series of procedures and methodologies through the use of scientific-based analyses in the field of optimal management of infrastructural assets.
This thesis is subdivided in several chapters, in which, the issues of quantification of the bridge structures’ deterioration state are intertwined with those related to the estimation of the seismic vulnerability assessment, from punctual level (single bridge) to territorial scale (infrastructural network).
The key topics discussed in this work are, at punctual level, statistical analyses on the effectiveness of in-situ investigations for the bridges’ seismic fragility estimation, sensitivity analyses on the influence of geometrical parameters on the seismic vulnerability assessment and the construction of fragility curves for bridges subjected to deterioration of key structural components.
At territorial scale, analyses of the restoring costs for bridge stocks, construction of life-cycle curves for bridges subjected to deterioration, simulations of time-dependent earthquake scenarios for infrastructural networks and procedures for the management of seismic emergency for railway networks are presented
Lessico nuovo in lingue di minoranza: ladino fassano e aranese a confronto.
No full textThis thesis focuses on the neology in minority languages, especially in the Ladin spoken in the Fassa Valley (Trentino-Alto Adige, Italy) and Aranes spoken in the Aran Valley (Catalonia, Spain), as a means of evaluation of the vitality of these languages. The real grade of Ladin and Aranes is definitely endangered as UNESCO Atlas of the World's Languages in Danger demonstrated in 2003, but I think that the rule of the neology in Ladin is enough important to improve this grade. For this reason, I will analyse the lexicon related to Information Technology (IT) as a semantic field rich in neologisms. In the first part I will examine two corpora: one, based upon the language as used in websites and databases and the other, taken from questionnaires carried out in elementary schools and middle schools. In the second part, I will provide concrete examples of how minority languages create new words and form neologisms (i.e. with innovative or conservative lexicon or morphological structures, etc.). This will produce an overview of neology in Ladin and Aranes. However, I will specify the rule of norms, use and contact throughout this process
Information Quality Requirements Engineering: a Goal-based Modeling and Reasoning Approach
No full textInformation Quality (IQ) has been always a growing concern for most organizations, since they depend on information for managing their daily tasks, delivering their services to their costumers, making important decisions, etc., and relying on low-quality information may negatively influence their overall performance, or even disasters in the case of critical systems (e.g., air traffic management systems, healthcare systems, etc.). Although there exist several techniques for dealing with IQ related problems in the literature (e.g., checksum, integrity constraints, etc.), but most of them propose solutions that are able to address the technical aspects of IQ, and seem to be limited in addressing social and organizational aspects. In other words, these techniques do not satisfy the needs of current complex systems, such as socio-technical systems, where humans and their interactions are considered as an integral part of the system along with the technical elements (e.g., healthcare systems, smart cities, etc.). This introduces the need of analyzing the social and organizational context where the system will eventually operates, since IQ related problems might manifest themselves in the actors' interactions and dependencies. Moreover, considering IQ requirements since the early phase of the system development (the requirements phase) can prevent revising the system to accommodate such needs after the system deployment, which might be too costly. Despite this, most of the Requirements Engineering (RE) frameworks and approaches either loosely define, or simply ignore IQ requirements. To this end, we propose a goal-oriented framework for modeling and reasoning about IQ requirements since the early phases of the system development. The proposed framework consists of (i) a modeling language that provides concepts and constructs for modeling IQ requirements; (ii) a set of analysis techniques that support system designers while performing the required analysis to verify the correctness and consistency of the IQ requirements model; (iii) an engineering methodology to assist designers in using the framework for capturing IQ requirements; and (iv) an automated tool-support, namely ST-IQ Tool. In addition, we empirically evaluated the framework to demonstrate its applicability, usefulness, and the scalability of its reasoning techniques by successfully applying it to a case study concerning a stock market system