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Enhancing Web 2.0 Usability: Handling The Local Contexts Of Web Users
No full textIn less than two decades, the World Wide Web has grown into one of the most popular channels that provide information about most aspects of the life (e.g., economic, education, political, etc.). For example, Web users from around the world can browse the Web for reading news, purchasing products, registering online courses, forecasting weather, etc. (referred to them as Web Readers).
Recently, the emergence of Web 2.0 has revolutionized the way information is designed and accessed over the Web. Web 2.0 sites enable Web users not only browsing the Web but also creating and updating Web contents. Hence, they can act as active Web authors. In addition, Web 2.0 sites/services can aggregate Web contents from several sites and display them together in a single Web page.
However, Web users originate from different communities and they implicitly follow their own semantics (refereed to as local contexts) to represent and interpret Web contents. As a consequence, the same real world concepts might be represented and interpreted in different ways by different Web authors and readers. Such concepts are referred to as Context-Sensitive Contents, or CSC for short. For example, the concept of price could be represented using different currencies (e.g., Euro, US Dollar) and according to different price formats. Also, date and time concepts could be represented using different time zones and according to different formats. This situation leads to several discrepancies which Web readers encounter on the Web, as they (need to) follow their contexts to interpret these CSCs.
One possible solution is to annotate CSCs with semantic metadata (i.e., authors' contexts), so that it becomes feasible for Web browsers to adapt the former to different users' contexts. However, the annotation of Web contents is a complex process due to the lack of annotation means that assist authors to perform this process.
From users' perspectives, the discrepancies that could rise from the interpretation of Web contents and the complexity of annotation process are considered as Web 2.0 usability problems.
This thesis proposes an approach for handling the aforementioned problems. This approach involves the following. Firstly, an evaluation of several designs alternatives to adapt CSCs to different users’ contexts. Secondly, a semantic model which describes how CSCs are annotated with context information. Thirdly, a context-aware architecture, which shows how our approach works seamlessly with Web technologies. Fourthly, an interactive annotation process that details how Web authors are assisted to specify their contexts and to annotate CSCs with suitable context information. Finally, an adaptation process that details how readers' applications adapt CSCs according to their readers' local contexts.(DOCSC06) -- FUNDP, 201
L'hyaluronidase-2 (Hyal2) et les acteurs du métabolisme de l'hyaluronan dans trois lignées cancéreuses et leurs cellules souches : N/A
No full textN/AN/A(DOCMED02) -- FUNDP, 201
META-ANALYSE DE PUCES A ADN POUR L'IDENTIFICATION DE GENES IMPLIQUES DANS L'HYPOXIE ET PROVOQUANT LE PHENOTYPE METASTATIQUE - MESURE DE LEUR EXPRESSION DANS DES CELLULES DE DIFFERENTS POTENTIELS METASTATIQUES EN HYPOXIE ET NORMOXIE
No full textMetastases are the final stage of cancer development and are responsible for many of the deaths from cancer. Recent studies have described the signaling pathways associated with metastatic phenotype. However, the actual involvement of these pathways in the initiation of metastasis is not always well understood.
Another key feature of tumors is the presence of hypoxic areas caused by a lack of oxygen in the center. Hypoxia leads to the expression of genes promoting the formation of metastases and the repression of genes that prevent their development.
Many studies of metastasis and / or the response to hypoxia have used DNA microarrays. However, they rarely have fully exploited this technique. As the data generated were made public, this work offers a re-analysis of these data sets to extract new information on the metastatic phenotype induced by hypoxia in several cancer cell lines, as well as validations of the hypotheses generated in silico.
Three complementary approaches were developed that allowed the selection of 165 genes of interest. Among these 165 genes, 91 have already been described in the literature as being involved in cancer. Among which 41 are known to regulate the metastatic potential. Twenty genes were also described to be involved in the response to hypoxia. Finally, these 165 genes can be classified into 42 different signaling pathways, among which 12 are directly linked to cancer, while 5 others are related to proliferation and cell motility. 1000 negative controls consisting of 165 randomly selected genes were unable to provide such results. Surprisingly, 5 signaling pathways, in which are involved the 165 genes of interest are related to pathogen recognition and to phagocytosis.
The expression profiles of 9 genes involved in one of the pathways of phagocytosis and one of the pathways of pathogen recognition were validated by real time RT-PCR. Migration tests were performed for three of these genes and two of them (PAK1 and CFL2) clearly show an involvement in cell migration providing new targets in the fight against this disease.Les métastases sont le stade ultime du développement cancéreux et sont responsables d’une grande partie des décès causés par le cancer. Des études récentes ont décrit les voies de signalisation liées au phénotype métastatique. Cependant, l'implication réelle de toutes ces voies dans l'initiation du potentiel métastatique n'est pas toujours bien comprise.
Une autre caractéristique clé des tumeurs est la présence de zones hypoxiques causées par un manque d'oxygène en leur centre. L'hypoxie conduit à l'expression de gènes favorisant la formation des métastases ainsi qu’à la répression de gènes empêchant leur développement.
De nombreuses études portant sur les métastases et/ou sur la réponse à l’hypoxie ont utilisé des puces à ADN. Cependant, elles ont rarement exploité pleinement cette technique. Comme les données générées ont été rendues publiques, ce travail propose une ré-analyse de ces jeux de données pour en extraire de nouvelles informations sur le phénotype métastatique induit par l'hypoxie dans différentes lignées cellulaires cancéreuses, ainsi que la validation des hypothèses ainsi générées.
Trois approches complémentaires ont été développées ; elles ont permis la sélection de 165 gènes d'intérêt. Sur ces 165 gènes, 91 ont déjà été décrits dans la littérature comme étant impliqués dans le cancer. Parmi eux, 41 sont connus pour réguler le potentiel métastatique. Vingt gènes ont également été décrits pour être impliqués dans la réponse à l'hypoxie. Enfin, ces 165 gènes peuvent être classés dans 42 voies de signalisation différentes, parmi lesquelles 12 sont directement liées au cancer, alors que 5 autres sont liées à la prolifération et la mobilité cellulaire. 1.000 contrôles négatifs composés de 165 gènes sélectionnés aléatoirement ont été incapables de fournir de tels résultats. De manière surprenante, 5 voies de signalisation, dans lesquelles sont impliqués les 165 gènes d’intérêt, sont liées à la reconnaissance de pathogènes et à la phagocytose.
Les profils d’expression de 9 gènes impliqués dans l'une des voies de phagocytose et dans l’une des voies de reconnaissance de pathogènes ont été validés par RT-PCR en temps réel. Des tests de migration ont été effectués pour trois de ces gènes et deux d’entre eux (PAK1 et CFL2) montrent clairement une implication dans la migration cellulaire offrant de nouvelles cibles dans la lutte contre cette maladie.(DOCSC03) -- FUNDP, 201
Monocouches auto-assemblées d’organothiols mono- et bipodes sur le cuivre
No full textThe present work is included in the framework of molecular assemblies on oxidizable metals surface and globally intends to create different functional coatings with specific properties. The general methodology involves the formation of Self-Assembled Monolayers (SAMs) of mono- or bipodal organothiols on copper substrates.
The first part of this thesis highlights the feasibility of the grafting on polycrystalline and electroreduced copper substrate of alcanethiol molecules with a single (thiol, RSH) or a double anchoring group (dithiol R(SH)2 and dithiocarboxylic RS2H). It comes out that the nature of the anchoring group has a strong impact on the structural properties of the monolayer, but also on its electrochemical and chemical (after immersion in another organothiol solution) stabilities. The dithiol SAMs lead to a significant increase of electrochemical stability and surface coverage by comparison with thiol and dithiocarboxylic SAMs; meanwhile, the dithiocarboxylic monolayers lead to the less stable coatings.
The second part of the study is devoted to the elaboration of amine terminated monolayers (NH2RSH or NH2R(SH)2) as promotor of adhesion between copper substrate and a polymer (epoxy resin or polyimide). In order to counter the reactivity of the amine function (oxidation and multilayers formation) and to obtain densely packed amine terminated SAMs, several optimisations of the processes are first investigated. A polymeric film (epoxy or polyimide) is then deposited on those monolayers: the presence of amine terminated SAMs on copper affords a significant increase of the copper-epoxy adhesion. However, this coating doesn’t show any improvement on the copper-polyimide adhesion.
Finally, a bilayer film formed by an adsorbed first part (CF3O(CF2)2RSH or CF3O(CF2)2R(SH)2 SAM) and a second mobile part (perfluoropolyether lubricant) is achieved. The perfluoroether-alcanethiol and dithiol SAMs own high blocking and insulating properties, even if they are loosely packed. The spreading of a thin lubricant film on their surface then permits the formation of a homogeneous bilayer film with high wettability. Furthermore, the presence of a monolayer leads to a decrease of the lubricant mobility, and therefore an improvement of its retention on the copper surface. This lower mobility is more pronounced for monolayers with large interchain spacing.Cette thèse s'inscrit dans la thématique des assemblages moléculaires sur des surfaces de métaux oxydables, en vue de former des revêtements fonctionnels avec des propriétés spécifiques. La méthodologie employée dans le cadre de cette thèse consiste à former des monocouches auto-assemblées d’organothiols mono- ou bipodes sur des substrats de cuivre.
La première partie de cette thèse a mis en évidence la faisabilité du greffage d’alcanethiol possédant un pied d’ancrage simple (thiol, RSH) ou double (dithiol (R(SH)2) et dithiocarboxylique (RS2H)) sur un substrat de cuivre polycristallin électroréduit. La nature du groupement ancreur s’est révélée être déterminante au niveau des propriétés structurelles de la monocouche résultante mais également du point de vue de sa stabilité électrochimique et en solution. La monocouche de dithiols offre une stabilité électrochimique ainsi qu’une capacité couvrante accrue comparativement au thiol et au dithiocarboxylique. Le dithiocarboxylique forme, quant à lui, le revêtement le moins stable.
La deuxième partie de ce manuscrit est dédiée à la formation de monocouche aminée alkylthiols (NH2RSH) et dithiols (NH2R(SH)2) en tant que promoteur d’adhésion entre le substrat de cuivre et un polymère (résine époxy ou polyimide). La complexité apportée par la fonction amine terminale a nécessité l’optimisation des conditions expérimentales afin d’aboutir à des monocouches organisées et de bonne qualité. Un film polymère (résine époxy ou polyimide) a ensuite été déposé sur le substrat de cuivre modifié par les monocouches aminées. La présence de la monocouche aminée (NH2RSH et NH2R(SH)2) sur le substrat de cuivre a apporté un gain substantiel en terme d’adhésion entre le cuivre et la résine époxy. Ce traitement de surface n’a, par contre, pas permis d’améliorer l’adhésion du film polyimide sur le cuivre.
Pour terminer, un système de bicouches moléculaires formé d’une partie fixe (SAM de type CF3O(CF2)2RSH ou CF3O(CF2)2R(SH)2) et d’une partie mobile (lubrifiant perfluoro polyéther) a été réalisé. Les monocouches de perfluoro-éther alcanethiols et dithiols, bien qu’elles possèdent une organisation moindre, ont montré des propriétés bloquante et isolante accrues. L’étalement du film lubrifiant à leur surface a abouti un système de bicouches homogène, mouillant parfaitement la surface. De plus, la présence d’une monocouche a permis d’améliorer la retenue du film lubrifiant en surface en atténuant sa mobilité. Cette retenue en surface est d’autant plus prononcée lorsque l’espace interchaîne au sein de la monocouche est important.(DOCSC02) -- FUNDP, 201
Développement de glycoconjugués ciblant la virulence bactérienne.
No full textThe treatment of bacterial infection is becoming difficult due to the increasing resistance of most clinically relevant bacterial strains. New type of weapons to tackle this growing problem are, therefore, urgently needed. Drugs targeting virulence is an alternative approach to treat infections provoked by resistant bacteria. By weakening pathogenic bacteria, the “antivirulence strategy” intends to increase their sensitivity against the host innate immunity such as components of human complement but also to classical antibiotics. In this context, disrupting the Gram negative bacterial cell wall biosynthesis is particularly interesting to target, as well as the microbial adhesion process necessary for further colonization. We developed during this work, new glycoconjugates targeting the bacterial heptose biosynthetic pathway and new multivalent glycoconjugates targeting bacterial adhesion processes.(DOCSC02) -- FUNDP, 201
RESPONSES OF PERIPHERAL BLOOD MONONUCLEAR CELLS TO MALACHITE GREEN IN THE ASIAN CATFISH COMBINING IN VITRO AND IN VIVO APPROACHES
No full textMalachite green (MG) is used as antiseptic to prevent and treat parasites, fungal and bacterial infections in fish. This disinfectant has been controversial and reported to have carcinogenic properties in mammals and to cause significant toxic effects in fish. Prohibited for use on fish intended for human consumption, this chemical and its residues are still commonly detected in fish products. Our concern is more about the rearing of one particular species, the Asian catfish, Pangasianodon hypophthalmus, one of the most economically important fish worldwide. The repeated violations concerning this species raise some questions on human health and risk assessment. Peripheral blood mononuclear cells (PBMC) were chosen to allow regular sampling in a limited invasive way. Through the combination of in vitro and in vivo approaches, some potential routes of research on the toxicity of MG in fish PBMC were highlighted. Proteomic analyses performed on both approaches suggested that MG could lead to possible disturbances of DNA transcription and replication as well as of DNA repair processes, potential disruption of normal cell division, disorganization of the cytoskeleton, modification of the expression of several molecular chaperones as well as of proteins linked to the ubiquitin proteasome system. Studies on MG toxicity should focus on the mitochondria that seemed to be an important target of the prohibited disinfectant. No protein involved in the oxidative stress response has been identified in any of the proteomic analyses performed. The glutathione peroxidase (GPx) and the glutathione S-transferase (GST) measured in the gills and in the liver did not show any significant changes while a significant decrease of hepatic catalase activity (47 %) was observed directly after MG exposure. Another aim of this study was to suggest a robust biomarker Protein Expression Signature (PES) to detect the illegal use of MG with the final objective to apply this biomarker signature to an in situ monitoring in fish farm conditions. This PES would consist of 11 suggested proteins differentially expressed following MG treatment up to one month after depuration. Before the use for regulatory purposes, a lot of work is still required and further studies on the suggested proteins are unavoidable to ensure the reliability of these biomarker candidates. Overall, the research project largely contributes to the investigation of MG toxic mechanism of action. Since it seems challenging to replace MG as fungicide, researches on MG toxicity should continue.e vert de malachite (MG) est utilisé comme antiseptique pour prévenir et traiter les parasites, les infections fongiques et bactériennes chez les poissons. Ce désinfectant a été controversé car susceptible d’avoir des propriétés cancérigènes chez les mammifères et d’induire des effets toxiques chez les poissons. Interdit à l’utilisation sur des poissons destinés à la consommation humaine, ce composé et ses résidus sont couramment détectés dans les filets de poissons. Notre étude porte plus particulièrement sur l’élevage du poisson-chat asiatique, Pangasianodon hypophthalmus, un des poissons les plus importants d’un point de vue économique. Les violations répétées concernant cette espèce posent des questions en termes de santé humaine et d’évaluation des risques. Les globules blancs mononucléaires du sang périphérique (PBMC) ont été choisis pour nous permettre un échantillonnage régulier peu invasif. Grâce à la combinaison des approches in vitro et in vivo, quelques voies de recherches potentielles sur la toxicité du MG dans les PBMC de poissons ont été soulignées. Les analyses protéomiques ont suggéré que le MG pouvait conduire à de possibles perturbations de la transcription, de la réplication mais également des processus de réparation de l’ADN, des perturbations potentielles de la division cellulaire, une désorganisation du cytosquelette, des modifications de l’expression de chaperones moléculaires, en plus, de protéines liées au système de l’ubiquitine protéasome. Finalement, les études sur la toxicité du MG devraient se focaliser sur les mitochondries qui semblent être une cible importante de ce dernier. Aucune protéine impliquée dans le stress oxydant n’a été identifiée dans les analyses protéomiques. De même, la glutathione peroxidase (GPx) et la glutathione S-transferase (GST), mesurés dans les branchies et le foie n'ont pas montré de variation significative. Une diminution significative de l’activité hépatique de la catalase (47 %), directement après exposition au MG, suggère son effet négatif sur cette enzyme antioxydante. Cette étude avait également pour but de suggérer une signature d’expression protéique biomarqueur robuste pour la détection de l’utilisation illégale du MG, avec, pour objectif final d’appliquer cette signature biomarqueur pour la surveillance dans les fermes aquacoles. Cette dernière serait composée de 11 protéines différentiellement exprimées suite au traitement au MG jusqu’à un mois après décontamination. Avant l’emploi à des fins réglementaires, beaucoup de travail sera encore nécessaire et des études plus approfondies concernant les protéines suggérées sont inévitables pour assurer la fiabilité de ces candidats biomarqueurs. Dans son ensembe, le projet de recherche contribue fortement à l'investigation du méchanisme d'action du MG. Le MG étant difficile à remplacer en tant que fongicide, les recherches sur le MG doivent continuer.(DOCSC03) -- FUNDP, 201
Phosphonic acid based initiator for Atom Transfer Radical Polymerization on metal oxide surfaces : Application to Solid Phase Microextraction (SPME)
No full textThe aim of the SPME-GC project was the creation of new metallic SPME fibers to be used for the detection and identification of small amounts of polluting substances in the environment (water, air, soil), in urines (medical application) as well as in food and beverages (food industry).
To reach this goal, we have worked out a “grafting from” method for the bonding of a layer of polymer, copolymer or composite materials onto the stainless steel wires.
The advantages of our method are twofold: the use of stainless steel as support ensures much greater mechanical robustness of the title objects and the onsite polymerization technique allows for the synthesis of coating layers exhibiting a wide range of affinity towards the compounds to be extracted from various samples (SPME) and/or to be separated and identified (GC).
A new ATRP initiator, 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid, has been synthesized and grafted as a film on a mechanically polished stainless steel substrate. Molecular integrity of the grafted initiator in the film, alkyl chain ordering, wettability were determined by X-ray photoelectron spectroscopy, polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) and water contact angles. Homopolymer and diblock copolymer brushes as well as the same “doped” by carbon nanotubes have been grafted from the flat stainless steel surfaces and characterized to check the effectiveness of the new initiator.
The extraction performances of the fibers (made as previously described) were assessed on different classes of compounds (polar, non-polar, aromatic, etc.) by headspace extraction. The optimization of the parameters affecting the extraction efficiency of the target compounds was studied as well as the reproducibility and the repeatability of the fiber. The fibers sustain more than 200 extractions during which they remain chemically stable and maintain good performances (detection limits lower than 2µg/l, repeatability, etc.). Considering their robustness together with their easy and inexpensive fabrication, these fibers could constitute promising alternatives to existing products.(DOCSC02) -- FUNDP, 201
Formal Modeling and Verification of Access-Control Policies
No full textThe construction of secure software is a notoriously difficult task. The abstract security requirements have to be turned into functional requirements and then implemented. However, only few techniques allow to verify that the implemented elements fulfill the originally expressed requirements. The potential gap between the specification and the implementation gets even wider with iterative development schemes where code (and sometimes specification) is updated numerous times.
In this document we propose a methodology aimed at facilitating the co-evolution of the security requirements and the implemented code. Focusing on the access-control perspective, we provide models and algorithms to specify the expected requirements and to extract the implemented access-control rules directly from the executable source code. Then we verify the conformance of the implemented features towards the specified requirements and, if inconsistencies are found, we provide potential corrective measures that can be applied directly into the source code.(DOCSC06) -- FUNDP, 201
Studies of local and global properties of interactome networks
No full textClassical genetic approaches have successfully assigned functional descriptors to thousands of genes across many species. However, daunting challenges remain ahead to associate genotype-phenotype relationships considering that rarely is a gene responsible for a single function. The central hypothesis of systems biology considers that complex and intricate networks of interacting genes and macromolecules, interactomes, underlie cellular functions.
Here, we describe efforts to experimentally chart the first binary proteome-scale systematic protein-protein interactome network map for a plant. Through an empirical framework, we demonstrate that the resulting dataset is of similar quality to well-documented interactions from the literature. We then describe an experimental strategy based on reference sets to standardized experimental methods for quality control of binary interactome data sets.
Finally, we explore three types of interactome network alterations that can help understand interactome function and help assign genotype-phenotype relationships: (1) engineered interaction-specific perturbation, (2) natural pathogen perturbation and, (3) perturbations of interaction through rewiring at the scale of evolution. We show that specific phenotypes can be associated to specific interaction loss.Les approches génétiques classiques ont permis l’attribution de descripteurs fonctionels à des milliers de gènes pour de nombreuses espèces. Cependant, l’identification de toutes les relations génotype-phénotype représente toujours un défi de taille, particulièrement parce qu’il apparait clair que rarement un gène est-il responsable d’une seule fonction biologique. L’hypothèse centrale de la biologie des systèmes propose que des réseaux denses et complexes, composés de gènes et macromolécules en interactions, ou interactomes, sous-tendent les fonctions cellulaires.
Nous décrivons nos travaux pour établir, de manière expérimentale et systématique, à l’échelle du protéome entier, la première carte de l’interactome d’une plante. Nous démontrons, grâce à un cadre empirique structuré, que l’ensemble des données résultant est de qualité équivalente aux interactions bien documentées de la litérature. Nous décrivons ensuite une stratégie expérimentale basée sur des référentiels d’interactions, pour standardiser les méthodes de controle de qualité des données d’interactomes binaires.
Enfin, nous explorons trois types d’altérations de réseaux qui peuvent permettre une meilleure compréhension du fonctionnement des interactomes et ainsi permettre l’établissement de relations génotype-phénotype: (1) ingénierie de perturbation d’interactions spécifiques, (2) perturbations naturelles par des pathogènes, et (3) remaniement d’interactions à l’échelle de l’évolution. Nous démontrons que des phénotypes spécifiques peuvent être associés à des pertes d’interactions spécifiques.(DOCSC03) -- FUNDP, 201
SYNTHESIS, SELF-ASSEMBLY AND OPTOELECTRONIC PROPERTIES OF HETEROAROMATIC CHROMOPHORES
No full textConjugated molecules constitute the elemental bricks of molecular materials that have given rise to considerable research efforts in basic and applied material science to develop new materials for information, communication and lighting technologies. The ambitions of the present work consisted to have a detailed understanding on the relationships between properties and the structure of π-conjugated molecules. To do this end, different classes of π-conjugated organic compounds were investigated delving into their synthetic processes and chimico-physical features.
The first part of the present doctoral thesis describes the synthesis and unprecedented photophysical properties of novel linear π-conjugated organic molecules to design wavelength shifters for an important medical imaging technique, the Positron Emission Tomography. Specifically, to achieve the wavelength conversion two approaches were considered, the push-pull approach and the heteroatom effect.
The second part of this work addressed instead a different category of π-conjugates, namely the extended π-conjugated porphyrin macrocycle. Porphyrins were here exploited to study their interactions with metallic surfaces and their ability to form patterned surface based on unique two-dimensional supramolecular assemblies. Specifically, the self-assembly processes were formed through non-covalent interactions between novel pyridyl-substituted porphyrins and investigated by means of the Scanning Tunneling Microscopy (STM) technique.
The third and last part focused on the preparation and physical characterization of diverse porphyrin-derived Double-Walled Carbon Nanotubes (DWCNTs) conjugates with the aim of get insights on the structural and electronic properties of these materials. In particular, COOH-derived DWCNTs, produced by means of a three-step oxidative protocol, were covalently linked to a porphyrin molecule. The synthesized DWCNTs-conjugates were also implemented in multilayered-type devices, fabricated with the aim of investigating the interaction of the porphyrin-derived CNTs with polymeric poly(3-hexylthiophene)-pyrene containing small amounts of [60]PCBM.Le molecole coniugate costituiscono gli elementi fondamentali dei cosiddetti materiali molecolari avendo dato luogo a un notevole sforzo della ricerca scientifica di base e applicata per sviluppare nuovi materiali per l’informazione, per la comunicazione e per l’illuminazione. L’interesse dietro le molecole coniugate è aumentato anche grazie allo sviluppo di metodologie sintetiche avanzate, come le reazioni di cross-coupling catalizzate da metalli di transizione, e di nuove tecniche di analisi che permettono un’accurata caratterizzazione di ciascuna molecola.
Le ambizioni di questo lavoro sono state quelle di fornire un’analisi dettagliata del rapporto che esiste fra le proprietà e la struttura di molecole coniugate. Per questo obiettivo, sono state prese in considerazione diverse classi di composti organici π-coniugati, approfondendo i loro aspetti sintetici e le loro caratteristiche chimico-fisiche.
Nelle prime parti di questo lavoro sono presentate molecole organiche π-coniugate per ideare convertitori di lunghezza d’onda, per un’importante tecnica medica d’imaging, la Tomografia ad Emissione di Positroni (acronimo: PET). In particolare, sono stati considerati due diversi approcci per produrre i suddetti convertitori, l’approccio donatore-accettore (o push-pull) e quello che sfrutta l’effetto dell’insersione di un eteroatomo. Alcuni di questi sistemi si sono rivelati degli ottimi convertitori di lunghezza d'onda.
Successivamente è stat affrontata una diversa classe di composti organici π-coniugati, le porfirine. Queste sono state studiate nell’ambito delle loro interazioni con superfici metalliche approfondendo le loro abilità di auto-assemblaggio bisimensionale (2D) per formare superfici con molecole organizzate che interagiscono attraverso interazioni supramolecolari. Queste superfici sono state poi analizzate attraverso la tecnica Scanning Tunneling Microscopy (STM). In particolare, per formare superifici di porfirine ordinate sfruttando un’interazione di tipo metallo-ligando, sono stati sintetizzati e studiati tre derivati caratterizzate da gruppi tipo fenil-etinil-piridina sostituiti nelle posizioni meso del macrociclo.
Le ultime sezioni di questo lavoro hanno riguardato la preparazione e la caratterizzazione fotofisica di diversi coniugati porfirina-Nanotubi di Carbonio di tipo double-wall (DWCNTs) con l’obiettivo di approfondire le relazioni struttura-proprietà di questi materiali. In particolare, DWCNTs ossidati, prodotti attraverso tre passaggi sintetici, sono stati covalentemente uniti ad una molecola di porfirina producendo tre differenti derivati che sono stati caratterizzati in maniera estensiva dal punto di vista strutturale e fotofisico. I materiali prodotti sono stati poi introdotti in un prototipo elettronico di tipo multistrato, fabricato allo scopo di studiare le interazioni fra i coniugati porfirina-nanotubi e la matrice polimerica inserita a sua volta nel dispositivo.(DOCSC02) -- FUNDP, 201