Evaluation of fluid transport processes in dental enamel. Methods to assess the relevance of enamel permeability in caries prevention and etching treatments.

This thesis evaluated in vivo and in vitro enamel permeability in different physiological and clinical conditions by means of SEM inspection of replicas of enamel surface obtained from polyvinyl siloxane impressions subsequently later cast in polyether impression ma-terial. This technique, not invasive and risk-free, allows the evaluation of fluid outflow from enamel surface and is able to detect the presence of small quantities of fluid, visu-alized as droplets. Fluid outflow on enamel surface represents enamel permeability. This property has a paramount importance in enamel physiolgy and pathology although its ef-fective role in adhesion, caries pathogenesis and prevention today is still not fully under-stood. The aim of the studies proposed was to evaluate enamel permeability changes in differ-ent conditions and to correlate the findings with the actual knowledge about enamel physiology, caries pathogenesis, fluoride and etchinhg treatments. To obtain confirmed data the replica technique has been supported by others specific techniques such as Ra-man and IR spectroscopy and EDX analysis. The first study carried out visualized fluid movement through dental enamel in vivo con-firmed that enamel is a permeable substrate and demonstrated that age and enamel per-meability are closely related. Examined samples from subjects of different ages showed a decreasing number and size of droplets with increasing age: freshly erupted permanent teeth showed many droplets covering the entire enamel surface. Droplets in permanent teeth were prominent along enamel perikymata. These results obtained through SEM inspection of replicas allowed innovative remarks in enamel physiology. An analogous testing has been developed for evaluation of enamel permeability in primary enamel. The results of this second study showed that primary enamel revealed a substantive permeability with droplets covering the entire enamel sur-face without any specific localization accordingly with histological features, without changes during aging signs of post-eruptive maturation. These results confirmed clinical data that showed a higher caries susceptibility for primary enamel and suggested a strong relationship between this one and enamel permeability. Topical fluoride application represents the gold standard for caries prevention although the mechanism of cariostatic effect of fluoride still needs to be clarified. The effects of topical fluoride application on enamel permeability were evaluated. Particularly two dif-ferent treatments (NaF and APF), with different pH, were examined. The major product of topical fluoride application was the deposition of CaF2-like globules. Replicas inspec-tion before and after both treatments at different times intervals and after specific addi-tional clinical interventions showed that such globule formed in vivo could be removed by professional toothbrushing, sonically and chemically by KOH. The results obtained in relation to enamel permeability showed that fluoride treatments temporarily reduced enamel water permeability when CaF2-like globules were removed. The in vivo perma-nence of decreased enamel permeability after CaF2 globules removal has been demon-strated for 1 h for NaF treated teeth and for at least 7 days for APF treated teeth. Important clinical consideration moved from these results. In fact the caries-preventing action of fluoride application may be due, in part, to its ability to decrease enamel water permeability and CaF2 like-globules seem to be indirectly involved in enamel protection over time maintaining low permeability. Others results obtained by metallographic microscope and SEM/EDX analyses of or-thodontic resins fluoride releasing and not demonstrated the relevance of topical fluo-ride application in decreasing the demineralization marks and modifying the chemical composition of the enamel in the treated area. These data obtained in both the experiments confirmed the efficacy of fluoride in caries prevention and contribute to clarify its mechanism of action. Adhesive dentistry is the gold standard for caries treatment and tooth rehabilitation and is founded on important chemical and physical principles involving both enamel and dentine substrates. Particularly acid etching of dental enamel enamel has usually employed in bonding pro-cedures increasing microscopic roughness. Different acids have been tested in the litera-ture suggesting several etching procedures. The acid-induced structural transformations in enamel after different etching treatments by means of Raman and IR spectroscopy analysis were evaluated and these findings were correlated with enamel permeability. Conventional etching with 37% phosphoric acid gel (H3PO4) for 30 s and etching with 15 % HCl for 120 s were investigated. Raman and IR spectroscopy showed that the treatment with both hydrochloric and phosphoric acids induced a decrease in the carbonate content of the enamel apatite. At the same time, both acids induced the formation of HPO42- ions. After H3PO4 treatment the bands due to the organic component of enamel decreased in intensity, while in-creased after HCl treatment. Replicas of H3PO4 treated enamel showed a strongly reduced permeability while replicas of HCl 15% treated samples showed a maintained permeability. A decrease of the enamel organic component, as resulted after H3PO4 treatment, involves a decrease in enamel permeability, while the increase of the organic matter (achieved by HCl treat-ment) still maintains enamel permeability. These results suggested a correlation between the amount of the organic matter, enamel permeability and caries. The results of the different studies carried out in this thesis contributed to clarify and improve the knowledge about enamel properties with important rebounds in theoretical and clinical aspects of Dentistry.

Pour une nouvelle poétique de l'extase : Abdelwahab Meddeb et l'héritage des poètes arabes et persans de l'Antiquité et du Moyen Ãge. Comparaisons et pistes de lecture intertextuelles.

Ce travail a pour objectif d’analyser la production narrative et poétique de l’écrivain tunisien Abdelwahab Meddeb, en comparaison avec les ouvrages du Moyen Age arabe et persan. L’auteur reprend en effet, par le biais de pratiques intertextuelles, les ouvrages des philosophes et des écrivains orientaux qui plus ont marqué le monde musulman, en arrivant à en faire une synthèse originale. Cette perspective multiculturelle ouvre la voie à une instance narrative polyphonique, où les textes se confondent et se mélangent. En un premier moment, l’étude porte sur les théories intertextuelles et leur application chez Meddeb ; dans la deuxième partie, l’analyse se concentre sur les correspondances internes à l’œuvre meddebienne, pour laisser la place, dans la dernière partie, aux aspects intertextuels que le texte francophone entretient avec les autres auteurs.

Empirical and fundamental mechanical tests in the evaluation of dough and bread rheological properties

Bread dough and particularly wheat dough, due to its viscoelastic behaviour, is probably the most dynamic and complicated rheological system and its characteristics are very important since they highly affect final products’ textural and sensorial properties. The study of dough rheology has been a very challenging task for many researchers since it can provide numerous information about dough formulation, structure and processing. This explains why dough rheology has been a matter of investigation for several decades. In this research rheological assessment of doughs and breads was performed by using empirical and fundamental methods at both small and large deformation, in order to characterize different types of doughs and final products such as bread. In order to study the structural aspects of food products, image analysis techniques was used for the integration of the information coming from empirical and fundamental rheological measurements. Evaluation of dough properties was carried out by texture profile analysis (TPA), dough stickiness (Chen and Hoseney cell) and uniaxial extensibility determination (Kieffer test) by using a Texture Analyser; small deformation rheological measurements, were performed on a controlled stress–strain rheometer; moreover the structure of different doughs was observed by using the image analysis; while bread characteristics were studied by using texture profile analysis (TPA) and image analysis. The objective of this research was to understand if the different rheological measurements were able to characterize and differentiate the different samples analysed. This in order to investigate the effect of different formulation and processing conditions on dough and final product from a structural point of view. For this aim the following different materials were performed and analysed: - frozen dough realized without yeast; - frozen dough and bread made with frozen dough; - doughs obtained by using different fermentation method; - doughs made by Kamut® flour; - dough and bread realized with the addition of ginger powder; - final products coming from different bakeries. The influence of sub-zero storage time on non-fermented and fermented dough viscoelastic performance and on final product (bread) was evaluated by using small deformation and large deformation methods. In general, the longer the sub-zero storage time the lower the positive viscoelastic attributes. The effect of fermentation time and of different type of fermentation (straight-dough method; sponge-and-dough procedure and poolish method) on rheological properties of doughs were investigated using empirical and fundamental analysis and image analysis was used to integrate this information throughout the evaluation of the dough’s structure. The results of fundamental rheological test showed that the incorporation of sourdough (poolish method) provoked changes that were different from those seen in the others type of fermentation. The affirmative action of some ingredients (extra-virgin olive oil and a liposomic lecithin emulsifier) to improve rheological characteristics of Kamut® dough has been confirmed also when subjected to low temperatures (24 hours and 48 hours at 4°C). Small deformation oscillatory measurements and large deformation mechanical tests performed provided useful information on the rheological properties of samples realized by using different amounts of ginger powder, showing that the sample with the highest amount of ginger powder (6%) had worse rheological characteristics compared to the other samples. Moisture content, specific volume, texture and crumb grain characteristics are the major quality attributes of bread products. The different sample analyzed, “Coppia Ferrarese”, “Pane Comune Romagnolo” and “Filone Terra di San Marino”, showed a decrease of crumb moisture and an increase in hardness over the storage time. Parameters such as cohesiveness and springiness, evaluated by TPA that are indicator of quality of fresh bread, decreased during the storage. By using empirical rheological tests we found several differences among the samples, due to the different ingredients used in formulation and the different process adopted to prepare the sample, but since these products are handmade, the differences could be account as a surplus value. In conclusion small deformation (in fundamental units) and large deformation methods showed a significant role in monitoring the influence of different ingredients used in formulation, different processing and storage conditions on dough viscoelastic performance and on final product. Finally the knowledge of formulation, processing and storage conditions together with the evaluation of structural and rheological characteristics is fundamental for the study of complex matrices like bakery products, where numerous variable can influence their final quality (e.g. raw material, bread-making procedure, time and temperature of the fermentation and baking).

Violenze in famiglia e molestie sul lavoro: aspetti socio-criminologici e giuridici nell'ordinamento italiano e francese.

L'elaborato si pone l'obiettivo di indagare il complesso quadro delle molestie in famiglia e sul lavoro nell'ordinamento italiano e di effettuare una comparazione con un ordinamento appartenente alla stessa tradizione giuridica, l'ordinamento francese. Nel corso dell'esposizione saranno ricostruiti gli aspetti socio-criminologici e giuridici delle molestie in famiglia verso i soggetti deboli, donne, minori, anziani o portatori di handicap, le molestie sul luogo di lavoro quali molestie sessuali e mobbing, le molestie a distanza o stalking, che per molti aspetti rappresentano un fenomeno sommerso e poco conosciuto. La tesi intende analizzare soprattutto le forme di molestie psicologiche e meno conosciute. La ricostruzione teorico-normativa degli argomenti trattati è integrata con i risultati di una ricerca quantitativa e qualitativa tratta dalla giurisprudenza dei due paesi. Il lavoro, quindi, è organizzato in due parti: la prima è incentrata sugli aspetti teorici, socio-criminologici e giuridici e la seconda è dedicata alla ricerca empirica, che è stata condotta utilizzando quali fonti di dati le sentenze della Suprema Corte di Cassazione italiana e francese.

La canzone sociale in Italia e in Francia tra protesta, nazione e rivoluzione (1830-1870)

La tesi di ricerca si propone di esaminare due tipologie della canzone sociale nel XIX secolo, ed in particolare attorno al 1848. Lo studio del canto nei contesti presi in esame (l’Italia e la Francia) viene analizzato attraverso due piste di ricerca parallele tra loro. Da una parte si è utilizzato il concetto di sociabilité per conoscere i luoghi di produzione e di diffusione del canto (l’importanza della strada, dell’osteria, delle goguette parigine, degli chansonniers des rues e dei cantastorie) e le circostanze di utilizzazione della canzone (la canzone in quanto forma d’espressione orale ma anche come scrittura murale, foglio volante e volantino). Dall’altra l’analisi si è focalizzata sui contenuti dei testi musicali per mette in luce le differenti tematiche, le immagini linguistiche e le figure retoriche cantate dall’artigiano-operaio per far emergere le differenze dell’idea di nazione tra i due contesti presi in esame. L’attenzione posta alla comparazione condurrà all’evidenziazione di punti di contatto tra le due nazioni. Il canto, infatti, costituisce un terreno privilegiato per comprendere l’immagine dell’“altro”: quale immagine possedevano i lavoratori francesi dell’Italia risorgimentale? E gli artigiani italiani come percepivano la nazione francese? Il canto viene analizzato non solamente come un “testo” ma anche come una “pratica sociale”. Queste operazioni permetteranno di sondare più in profondità la funzione sociale svolta dalla canzone all’interno della cultura popolare e la sua importanza in quanto forma d’espressione e vettore di politicizzazione. La duplice utilizzazione del canto, in quanto “testo” e “pratica”, consente di inserire la ricerca all’interno di un filone storiografico che dalla storia sociale si muove a quella culturale. La canzone sociale rappresenta un fertile terreno di ricerca, non solamente all’interno di un singolo territorio nazionale, ma possiede un prezioso valore euristico in funzione comparativa.

Implicit computational complexity and probabilistic classes

The thesis applies the ICC tecniques to the probabilistic polinomial complexity classes in order to get an implicit characterization of them. The main contribution lays on the implicit characterization of PP (which stands for Probabilistic Polynomial Time) class, showing a syntactical characterisation of PP and a static complexity analyser able to recognise if an imperative program computes in Probabilistic Polynomial Time. The thesis is divided in two parts. The first part focuses on solving the problem by creating a prototype of functional language (a probabilistic variation of lambda calculus with bounded recursion) that is sound and complete respect to Probabilistic Prolynomial Time. The second part, instead, reverses the problem and develops a feasible way to verify if a program, written with a prototype of imperative programming language, is running in Probabilistic polynomial time or not. This thesis would characterise itself as one of the first step for Implicit Computational Complexity over probabilistic classes. There are still open hard problem to investigate and try to solve. There are a lot of theoretical aspects strongly connected with these topics and I expect that in the future there will be wide attention to ICC and probabilistic classes.

La ville picaresque

Cet extrait (le début du projet) peut être essentiellement considéré comme un travail de synthèse, de traduction et d’argumentation concernant un des textes de référence parmi les plus importants au sujet de la littérature picaresque : “La literatura picaresca desde la historia social” écrit par Jose Antonio Maravall. Mon but en développant ce projet était de me focaliser sur les idées principales contenues dans ce volume et en particulier sur la relation existante entre la littérature picaresque et le concept de ville, en termes urbanistiques. Je tiens à souligner le fait que ce travail a été longuement approfondi dans mes nombreuses activités d’étude et de recherche et en me référant, volontairement, au texte lui-même. La raison fondamentale de mon désir de rester près du texte se justifie par le fait que je venais de commence ce qui seraient mes futures activités de recherche de doctorat. J’ai utilisé ces idées à propos de la littérature picaresque, idées qui sont aujourd’hui universellement acceptées, afin de m’orienter moi-même dans ce genre littéraire. Les autres idées que j’ai étudiées et décrites au cours de mes activités de recherche successives sont plus personnelles, car j’avais eu l’occasion de les analyser auparavant. Ce travail n’inclut pas seulement des activités de recherche , mais il s’est agi aussi d’un projet de traduction puisque j’ai dû traduire de l’espagnol(texte original) en italien, pour ensuite concevoir et puis rédiger ma synthèse et mon argumentation en langue française. En conclusion, je peux affirmer que j’ai été capable de construire de solides bases pour élaborer et planifier ma thèse de Doctorat, avec les typiques thèmes de la littérature picaresque, pour exemple la recherche de la nourriture dans la ville.

Expériences du sacré et (dé)figurations du Christ. Artaud, Beckett, Pasolini

« Dieu est mort » proclame à l’envi le fou nietzschéen. C’est sous l’égide inquiète de cette assertion paroxystique, traduisant ce «malaise de la culture» qu’évoquait Freud, que la pensée, la littérature et l’art du XXe siècle européen évoluent. Cependant, le christianisme dont ce cri signe l’extrême décadence, n’est pas seul à imprégner les productions artistiques de ce siècle, même les plus prétendument athées, mais avant tout la figure du Christ - autour de laquelle sont structurés tant cette religion que son système de croyance – semble, littéralement et paradoxalement, infester l’imaginaire du XXe siècle, sous des formes plus ou moins fantasmatiques. Ce travail se propose ainsi précisément d’étudier, dans une optique interdisciplinaire entre littérature, art et cinéma, cette dynamique controversée, ses causes, les processus qui la sous-tendent ainsi que ses effets, à partir des œuvres de trois auteurs : Artaud, Beckett et Pasolini. L’objectif est de fournir une clé de lecture de cette problématique qui mette en exergue comment « la conversion de la croyance », comme la définit Deleuze, à laquelle ces auteurs participent, n’engendre pas un rejet purement profanatoire du christianisme mais, à l’inverse, la mise en œuvre d’un mouvement aussi violent que libératoire qualifié par Nancy de « déconstruction du christianisme ». Ce travail entend donc étudier tout d’abord à la lumière de l’expérience intérieure de Bataille, l’imaginaire christique qui sous-tend leurs productions ; puis, d’en analyser les mouvements et les effets en les questionnant sur la base de cette dynamique ambivalente que Grossman nomme la « défiguration de la forme christique ». Les excès délirants d’Artaud, l’ironie tranchante de Beckett et la passion ambiguë de Pasolini s’avèrent ainsi participer à un mouvement commun qui, oscillant entre reprise et rejet, débouche sur une attitude tout aussi destructive que revitalisante des fondements du christianisme.