Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Cette thèse décrit une stratégie de synthèse de nouvelles générations des nanoparticules (NPs) pour applications biomédicales, visant à une amélioration de leurs performances pour l’imagerie, le diagnostic thérapeutique. Ces NPs présentent plusieurs fonctionnalités leur permettant de réaliser des tâches multiples. Deux types de sondes bimodales ont été développés et étudiés afin d'évaluer leur potentiel comme agents (1) de contraste en IRM et (2) luminescents. Ces objetscombinent les propriétés des complexes de lanthanide (Ln3+) et celles des NPs de silice ou de type coeur-écorce Fe2O3@SiO2 pour une imagerie bimodale. Ces NPs testées sur des cellules vivantes ont permis d’illustrer la preuve du concept aussi bien en IRM avec une augmentation d'intensité des images et un impact significatif sur les relaxivities r1, r2 et r2* qu’en photoluminescence. L’étude du système coeur-écorce a montré que l’influence du contrôle fin de l’écorce autour du noyau d'oxyde de fer a pu être modélisée. / This thesis describes a strategy of synthesis of new generations of nanoparticles (NPs) for biomedical applications, aiming at an improvement of their performances for the imaging, and the therapeutic diagnosis. These NPs present several functionalities enabling them to carry out multiple tasks. Two types of bimodal probes were developed and studied so as to evaluate their potential as contrast agents (1) in MRI and (2) and luminescence. These objects combine the properties of the lanthanide complexes (Ln3+) and those of NPs of silica or core/shell Fe2O3@SiO2 for a bimodal imaging. These NPs tested on living cells were able to illustrate the proof of the concept not only in MRI with an increase of intensity of the images and a significant impact on the relaxivities r1, r 2 and r2* but also in photoluminescence. The study of the core/shell system showed that the influence of the fine control of the shell around the iron oxide core could be modeled.

La spectroscopie d’émission est un outil puissant pour obtenir des informations sur lesprocessus microscopiques dans un plasma de décharge hors-équilibre (décharge couronne)dans des milieux denses tels que le gaz supercritique à haute pression et les liquides. Lesobservations spectroscopiques de la lumière émise à partir d'une zone d'ionisation créée parune décharge entre une pointe fine et un plan sont utilisées pour caractériser l'environnementlocal des atomes ou des molécules émettrices. Les caractéristiques spectrales observablesétant sensibles à l'environnement immédiat de l'espèce émettrice, rend la spectroscopieoptique très utile pour l'étude du plasma hors-équilibre en fonction des paramètres du milieu(pression et température).Dans ce travail, nous avons étudié les caractéristiques courant-tension et lacomposition spectrale d’un cryoplasma initié par une décharge couronne dans l'hélium liquideet gazeux à des températures cryogéniques. Ces expériences ont été effectuées pour un certainnombre de températures fixes de 300 K à 4,2 K dans une plage de pression de 0,1 à 10 MPa.Ces conditions couvrent une large région des états thermodynamiques de la matière avec unedensité d'environ 1019 cm-3 pour le gaz à une densité de 2*1022 cm-3 pour le liquide. / Fluorescence spectroscopy is a powerful tool to obtain information on microscopicprocesses in non-equilibrium discharge plasma (corona) in dense media such as high pressuresupercritical gas and even liquids. Spectroscopic observations of the light emitted from anionization zone near a tip electrode can be used to determine structural information of thelocal environment of the emitting atoms or molecules. The spectral features observable aresensitive to the immediate surroundings of the emitting species, which makes emissionspectroscopy very useful for study of the cold nonequilibrium plasma varying the pressureand the temperature.In this work, we have studied the current-voltage characteristics and spectralcomposition of helium cryoplasma initiated with a corona discharge in gaseous and liquidhelium. A cryoplasma has been realized in laboratory conditions using corona discharge ingaseous and liquid Helium at cryogenic temperatures of the matter. Experiments were carriedout at a number of fixed temperatures from 300 K down to 4.2 K within the pressure range0.1÷10 MPa. The conditions covered a wide region of thermodynamic states of the mattersuch as from a gas with density of ~1019 cm-3 up to liquid Helium with density of 2*1022cm-3.

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L’objectif principal de ces travaux de thèse était de comprendre l’impact de la chimie de surface de NPs lors de leur interaction avec des interfaces biologiques. Deux sortes de NPs cœurs-coquilles ont été étudiées : des NPs sphériques de silice mésoporeuse Fe3O4@MSN de 100 nm de diamètre, contenant un cœur magnétique et des NPs composées d’analogues de bleu de Prusse (ABP) de formes cubiques (BP), cuboïdes (FeNi), ou polyédriques Au@BP contenant un cœur d’or, de tailles comprises entre 47 et 67 nm. Ces NPs différent par leur taille, leur composition chimique et leur forme. Les NPs de silice mésoporeuse, particulièrement étudiées ces dernières années pour leurs potentielles applications médicales, ont été choisies pour estimer la pertinence du recours à des modèles membranaires supportés pour l’évaluation de la sécurité biologique de nanomatériaux pour la santé. Les NPs Fe3O4@MSN ont été synthétisées de façon homogène et reproductible. Ces NPs ont ensuite été fonctionnalisées, par greffage de groupements PEG sur la silice, ou recouvertes avec une bicouche lipidique. L’influence des propriétés de surface sur la stabilité en suspension de ces NPs a été caractérisée dans différents milieux. Les effets de ces NPs sur la viabilité cellulaire et la cinétique d’internalisation ont été suivis sur une lignée cellulaire d’hépato-carcinome humain HepG2. Afin d’appréhender la relation entre les propriétés de surface des NPs et leurs effets sur les cellules, l’interaction des NPs avec des modèles membranaires a été étudiée. Les interactions des NPs avec des modèles membranaires ont été suivies par microbalance à quartz (QCM-D) et résonance plasmonique de surface (RPS). Les NPs fonctionnalisées sont plus rapidement internalisées que les NPs natives, en particulier les NPs recouvertes de bicouches lipidiques, mais sont moins toxiques pour les cellules HepG2. La présence de protéines de sérum de veau fœtal induit la formation d’une couronne de protéines qui influence l’interaction des NPs natives avec les membranes. Par contre, les groupements PEG ou le recouvrement lipidique forment un encombrement stérique limitant l’adhésion des protéines à la surface, qui n’influencent donc pas l’interaction des NPs avec les membranes. D’autre part, les NPs d’ABP ont été recouvertes avec des bicouches lipidiques. Les NPs polyédrique Au@BP contiennent un cœur d’or pour leur conférer des propriétés plasmoniques. La forme des NPs, sphériques, cubiques, cuboïdes ou polyédriques, n’influence pas le recouvrement lipidique. Ces différentes NPs, agrégées à 150 mM de NaCl, sont stabilisées en suspension par la formation d’une bicouche lipidique supportée en surface. L’influence de la forme sur la sécurité biologique des NPs peut ainsi être étudiée, celles-ci ayant des propriétés de surface communes mais différentes formes. / This work is a part of a multidisciplinary project focused on the safety of nanoparticles (NPs) developed for theranostic applications. The goal of this thesis is to investigate the role of surface chemistry of NPs at the biological interface. Two types of core-shell NPs have been studied: spherical mesoporous silica Fe3O4@MSN, with a diameter of 100 nm and a magnetic core, and cubic, cuboid and polyhedral NPs composed of Prussian blue analogous, presenting sizes comprised between 47 and 67 nm. The polyhedral Prussian blue NPs Au@BP contain a gold core. The NPs present different sizes, shapes and chemical compositions. Mesoporous silica NPs (MSN), particularly studied for their potential medical applications, have been used to evidence the relevance of model membranes to investigate NPs safety. First, Fe3O4@MSN were homogeneously synthesized, in reproducible 100 mg batches. These NPs have been functionalized by PEG grafting and lipid coating. The influence of the surface properties on the NPs stability have been characterized in various media. A human hepatocarcinoma cell line HepG2 have been used to measure the cell viability and observe the uptake kinetics when the cells are incubated with Fe3O4@MSN. To rely the surface properties of the NPs to their cell effects, the interaction of NPs with membrane models have been studied. Quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (RPS) were used to follow NPs-model membrane interactions. Functionalized NPs were uptaken faster than the bare ones, in particular lipid coated NPs, but were less cytotoxic for HepG2 cells. The presence of fetal calf serum proteins reduces the interaction of bare Fe3O4@MSN with model membranes, due to the protein corona that formed around the NPs. However, the presence of proteins doesn’t change NPs-model membranes interactions when NPs are functionalized by PEG grafting or coated with a lipid bilayer. The PEG groups and the lipid bilayers constitute a steric barrier which reduces the protein adhesion at the NPs surfaces. On the other hand, Prussian blue analogous NPs were also coated with lipid bilayers. The golden core of the polyhedral one’s confers localized plasmon properties. The lipid bilayer coating is equally performed on spherical, cubic, cuboid or polyhedral shapes of the various NPs. These different NPs are aggregated in high ionic strength conditions, with 150 mM NaCl, but dispersed when coated by lipid bilayer. The influence of the shape on the safety of the NPs may be compared, using these NPs with common surface coating but various shapes.

In times of social distancing and restrictions, ecclesiological challenges arise for the church as a room that under normal circumstances gather people for services. When the church cannot be used the way it is intended to, it raises questions about the functions of the room. The new corona virus pandemic is a crisis that challenges our perception of the church buildings’ functions and aspects. This thesis is a case study that took place in the Cathedral of Stockholm, also called Storkyrkan, during Holy week and Easter. The purpose of this thesis is to study what ecclesiological implications this new reality has on how co-workers and visitors make use of the room. Through observation of the room and interviews of visitors and co-workers I identify five aspects of Storkyrkan that characterize what functions a church building can have during a crisis. The study finds that through the circumstantial changes of the usage of the room, the materiality of it is amplified. It also shows that many types of people visit and use the room in various ways. They are all connected as a collective in a network through the words, artifacts, music, and practises that are a part of this space. Instead of closing due to the pandemic, Storkyrkan was an open room which generated possibilities for people to use it. In times of social distancing, when people are encouraged to stay away from each other, the church brought people together, though in a much smaller number. This happened both in the physical room and in the virtual room online. These are all sources of lived ecclesiology, which is understood through people’s lives and actions.

This diploma thesis is aimed to the corona-like discharge in solutions of alcohols, specifically in ethanol, methanol, glycerol, butanol and isopropyl alcohol. The electric discharge was diagnosed by two methods. The first method was the measuring of electrical characteristics. Current-voltage characteristics were constructed from the measured average values of voltage and current. The breakdown voltages were determined from the current-voltage characteristics. The breakdown voltages of the individual alcohol solutions were dependent on the alcohol concentration, polarity of the electrodes in the reactor and solution conductivity. The breakdown voltage was determined for solutions of butanol, glycerol and isopropyl alcohol with a concentration of 20 vol. % and conductivity of 200 µS. The highest value of the breakdown voltage was determined for solution of glycerol at 580 V. The lowest voltage at which the discharge was observed was estimated for butanol (320 V), but due to the limited miscibility with water this value is inaccurate, and therefore in the second part of experiment butanol was not used. Alcohol series was supplemented with methanol. The second diagnostic method was the proton ionization mass spectrometry with the time of flight analyzer. The products formed in the reactor due to the plasma discharge were identified from the mass spectrum. Mostly, aliphatic hydrocarbons and their radicals were detected. The amount of products was observed in the dependence on the changing experimental conditions: alcohol concentration in the solution, the polarity of the electrodes in the reactor and the duration of the discharge. Only a small amount of compounds were detected in methanol. However, more molecules were formed with the increasing carbon chain in the alcohol molecule. More compounds were also detected with the increasing alcohol concentration and in case of the negative polarity of the main electrode. The formation of acetaldehyde as a typical discharge product was studied in details. Its production in time was observed and the reaction pathways of its formation in the ethanol solution were suggested.

This diploma thesis focuses on quinine solutions and quality of these solutions after applying plasma discharge. These electric discharges can be used to destroy some substances from the water. The theoretical part is focused on description of electric discharges in liquids and on the properties of quinine. In the experimental part, the properties of quinine solutions containing different electrolytes were analysed by UV-VIS spectrophotometer and fluorescence spectroscopy. Two different types of configurations of plasma discharges in liquids were used. Solutions were compared on the base of different concentration of quinine, different electrolytes, different configurations of plasma discharges and pH values of the solutions. Furthermore, the experimental work focuses on quinine solutions with the sodium nitrate. The time instability of the solutions was analysed. Also, the influence of the solution age and different types of the plasma discharge on the excitation and emission spectra of quinine were investigated.

The present work attempts to highlight the difference in perception among the audience in digital and analog arenas by comparing the play Offending the Audience by Peter Handke, the filmed staged version thereof, directed by Claus Peymann in 1966 and the video performance #allesdichtmachen (2021). The aim is to discern in what respects these works are similar, where they diverge and whether there is a lowest common denominator, which makes a particular aesthetic representation of the content relevant to the audience. Furthermore the question is raised whether, and how, a new sense of responsibility for the creators and audiences arises from new habits of reception. Can the digital consumer provide a significant opportunity for live theatre, struggling in the shadow of the Covid-19 crises, by helping it regain its role as a brilliant entertainer, important custodian and mediator of arts and culture? / Die vorliegende Arbeit versucht mittels Gegenüberstellung der Publikumsbeschimpfung von Peter Handke bzw. dessen szenischer Umsetzung durch Claus Peymann aus dem Jahre 1966 und der Video-Kunstaktion #allesdichtmachen (2021) aufzuzeigen, welche Erlebnisräume der analogen und digitalen Rezeption entspringen. Hierbei gilt es herauszuarbeiten, wie sich diese unterscheiden, worin sie sich gleichen und ob es einen kleinsten gemeinsamen Nenner gibt, der die ästhetische Spiegelung des Inhalts/Contents zu einem Auftritt von Relevanz werden lässt. Im Zuge dessen soll auch erörtert werden, inwiefern oder ob den Rezipienten bzw. Theatermachern aus veränderten Rezeptionsgewohnheiten eine Verantwortlichkeit erwächst und ob der digitalisierte Teilnehmer in weiterer Konsequenz eine Chance für das Live-Theater darstellt, das im Schatten der Covid-19-Krise versuchen muss, die von ihm verlorene Pole-Position als kultureller Verwalter, pädagogischer Vermittler und genialer Unterhalter zurückzuerobern.

The work deals with the measurement of CV characteristics of photovoltaic cells and the consequent derivation of the free / bound charge in the volume. It also discusses factors that influence these measurements.