Les expériences de laboratoire ont montré que la photo-irradiation ultraviolette d'analogues de glaces astrophysiques suivie de leur réchauffement à température ambiante mène à la formation de résidus organiques réfractaires. Ces résidus, solubles dans l'eau, consistent en un riche mélange de composés organiques incluant entre autres des acides aminés, molécules potentiellement importantes pour la chimie prébiotique. Ces résidus sont considérés comme des analogues de la matière organique réfractaire que l'on pense être synthétisée sur les grains de poussière dans les nuages moléculaires et/ou dans les disques protoplanétaires, produit de l'évolution des glaces, et qui pourra être accrétée plus tard en comètes ou en astéroïdes et finalement délivrée sur la Terre primitive. Ainsi, l'étude de ces analogues, produits dans des conditions astrophysiques pertinentes, représente un outil efficace pour explorer les processus à l'origine de la formation des molécules organiques complexes dans le Système Solaire et en particulier la possible introduction d'excès énantiomériques dans les molécules chirales.Ce travail de thèse est consacré à l'étude de ces résidus organiques, leur caractérisation et les applications astrophysiques de ces résultats. Nous avons utilisé différentes techniques d'analyse comme la chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC MS, classique et multidimensionnelle), la spectrométrie de masse par résonnance cyclotronique ionique à transformée de Fourier (FT ICR MS) ou encore la spectroscopie infrarouge. Nous avons mesuré les excès énantiomériques induits dans cinq acides aminés par irradiation de nos analogues avec de la lumière UV polarisée circulairement (UV CPL) et insérons nos résultats dans le cadre d'un scénario astrophysique cohérent pour expliquer l'origine des excès énantiomériques observés dans les acides aminés météoritiques. Nous avons étudié le contenu en acides aminés de la météorite de "Paris" et montré des similarités avec la distribution en acides aminés de nos résidus organiques. Nous avons également produit des analogues plus réalistes de grains interstellaires en incluant une surface silicatée, afin de tester l’effet potentiel de cette surface sur la formation et la nature des résidus organiques. Enfin, nous effectuons une discussion générale à propos de la pertinence de ces résultats dans le contexte astrophysique et soulignons le possible lien entre astrochimie et chimie prébiotique. / Laboratory experiments have shown that ultraviolet photo-irradiation of astrophysical ice analogs and their following warm-up until room temperature lead to the formation of refractory organic residues. These residues consist of rich mixtures of organic compounds, including amino acids, which have a potential importance for prebiotic chemistry. They are considered as analogs of the organic refractory materials that are thought to be synthesized on dust grains in molecular clouds and/or in protoplanetary disks, as a product of ices evolution, and that could be later accreted into comets and asteroids and eventually be delivered to the early Earth. Hence, the study of these analogs, produced under astrophysically relevant conditions, represents a valid tool to investigate the processes at work for the origin of complex organic molecules in the Solar System and in particular the possible introduction of enantiomeric excesses in chiral molecules. This PhD work is devoted to the study of these laboratory organic residues, their characterization and the astrophysical applications of the results. We used different analytical techniques such as gas chromatography mass spectrometry (GC MS, classical and multidimensional), Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS), and infrared spectroscopy. We measured the enantiomeric excesses induced in five chiral amino acids by UV circularly polarized light (UV CPL) irradiation of our analogs and insert our result in a coherent astrophysical scenario for the origin of the enantiomeric excesses observed in meteoritic amino acids. We studied the amino acid content of the Paris meteorite and evidence some similarities with the distribution of the amino acids in our organic residues. We also produced more realistic analogs of interstellar grains, including a silicate surface, to test the potential effect of such a surface on the formation and nature of organic residues. Finally, we discuss the significance of these results in the astrophysical context and the possible relationship between astrochemistry and prebiotic chemistry.

This dissertation thesis concerns with Analysis of Influence of Collagen Organization on Mechanical Properties of Arteries and it is divided into three main parts. Motivation for this dissertation thesis was in a study reviewing effect of material model upon resulting stresses in AAA. The effect was calculated in 70 patient-specific geometries of AAA, which exceeds the number of geometries in other scientific papers by one order. Within this study, two material models were used, i.e. real one and 100× stiffer, and obtained stresses were mutually compared. It was quantified that peak stress difference can be higher than 20 % in 10% of patients and therefore the real material model should be preferred over the artificial one although operation with this model is more demanding. The second part of this thesis deals with an identification of structural parameters (orientation and dispersion of collagen fibres) of porcine aortic tissue by using adjusted Fast Fourier Transform based algorithm. The extracted structural parameters were inserted into two-layer structure-motivated constitutive model Martufi-Gasser. This model was validated and its predictive capabilities were also tested with fine results. The most important information obtained from the digital image processing of ~9000 micrographs is existence of only one family of dispersed collagen fibres which breaks the current dogma present in many scientific papers about two families of collagen fibres. The third part concerns with a proposal of an automated phase-correlation based algorithm for obtaining collagen fibre direction from polarized light microscopy images. The proposed algorithm was verified and validated and it yields histograms of collagen fibre directions with overall number of measured points larger than it would be possible to get from any manual measurement. The limitation of the original proposed algorithm is in 90° period of polarized light intensity, thus the method results in angles in the range of 0°–90. Therefore the end of the thesis is dedicated resolving this problem and obtaining real angles in a span of 0°–180°. To this end, the microscope set-up was changed and the algorithm was adjusted accordingly. The original and the adjusted algorithms are collagen-specific, fast and an operator independent. Despite all the author´s effort put into collagen fibre waviness quantification directly from the histograms, the waviness has not been quantified yet in this way and it remains at the stage of research.

No description available.

In this work, we demonstrate an inimitable liquid crystalline template strategy for the preparation of water dispersible electrically conducting poly(3,4-ethylenedioxythiophene) nanospindles (PEDOTSs). PEDOTSs were formed during the polymerization of the spindle shaped liquid crystalline phase of “EDOT–PDPSA” which was formed by the specific interactions of 3,4-ethylenedioxythiophene (EDOT) with 3-pentadecyl phenol-4-sulphonic acid (PDPSA). Liquid crystalline phases were characterized by Polarized Light Microscopic (PLM) analyses, rheology and XRD. Morphology and solid state ordering of conducting nanospindles were characterized by SEM, TEM and XRD. PEDOTSs exhibited an electrical conductivity of ~2.79 S cm⁻¹ and a good thermal stability (~300 °C), which suggests their applicability in fabricating high temperature electronic devices. Furthermore, electrochemical studies of PEDOTS modified glassy carbon electrodes (GCEs) showed an oxidation peak of ascorbic acid at a lower potential of 0.046 V with a peak current about 10 times (91.68 µA) higher than that of the bare GCE with excellent electrode stability, proposing that it can be used as a steady electrode for the electro-catalytic oxidation of similar molecules.

Measurements on coccolith abundance and mass can be used as a signal of primary productivity and pelagic calcification in response to environmental change. The Leeuwin Current (LC) is known to transport warm and low-salinity waters from the Indo-Pacific Warm Pool (IPWP) southwards along the coast of West Australia. Along with the onset of continental aridity during late Neogene, increased strength of the LC may have played a role in reef expansion on the Northwest Shelf. In this study the morphological variation in size and mass of reticulofenestrid coccoliths was assessed in material from IODP Site U1461 in the eastern Indian Ocean spanning the past 500 ka. Both the absolute abundance of all reticulofenstrid coccoliths (Emiliania huxleyi, Reticulofenestra spp., Gephyrocapsa spp. and Pseudoemiliania spp.) was determined, as well as the relative abundance of large versus small coccoliths. Coccolith size and mass were measured quantitatively under circularly polarized light. The data was compared to variations in sea surface temperatures (SST) of the LC, and to continental aridity of Australia. SST fluctuations could influence coccolithophore productivity by affecting their metabolic rate, whereas continental aridity may influence the influx of terrestrial matter by wind. The investigated interval is dominated by small species of Gephyrocapsa. Peak values of absolute abundance and mass were observed during Marine Isotope Stage (MIS) 11, an interglacial period of extended warmth and humidity. These results coupled with high densities of aragonite needles in the same samples indicate the sediments were diluted by material overflowing from the adjacent shallow- water carbonate platform, analogous to the whiting events observed in the modern-day Bahamas. A decrease in abundance of Gephyrocapsa caribbeanica at 240 ka can be linked to the timing of their last common occurrence (LCO), within MIS 7. The subsequent shift to Gephyrocapsa oceanica as the dominant large species may indicate an ecological replacement of G. caribbeanica, or signify warm and low-salinity waters. / Mätningar av abundans och massa hos coccoliter kan användas som en signal för primärproduktion och pelagisk förkalkning som resultat av miljöförändringar. Leeuwin Current (LC) är känd för att transportera varmt vatten och vatten med låg salthalt från Indo-Pacific Warm Pool (IPWP) söderut längs kusten i västra Australien. Tillsammans med början av kontinental torka under sen Neogen kan ökad styrka hos LC ha spelat en roll i expansionen av rev på nordvästsockeln. I denna studie bedömdes den morfologiska variationen i storlek och massa hos coccoliter i material från IODP plats U1461 i östra Indiska oceanen från de senaste 500 000 åren. Både den absoluta abundansen av alla reticulofenstridcoccoliter (Emiliania huxleyi, Reticulofenestra spp., Gephyrocapsa spp. och Pseudoemiliania spp.) bestämdes, liksom den relativa abundansen av stora jämfört med små coccoliter. Storlek och massa av coccoliter mättes kvantitativt under cirkulärt polariserat ljus. Uppgifterna jämfördes med variationer i havsytans temperatur (SST) hos LC, och med kontinental torrhet i Australien. SST-fluktuationer kan påverka produktiviteten hos coccolitoforider genom att påverka deras metabolism, medan kontinental torrhet kan påverka inflödet av markmaterial med vind. Det undersökta intervallet domineras av små arter av Gephyrocapsa. Toppvärden av absolut abundans och massa observerades under marinisotopsteget (MIS) 11, en interglacial period med förlängd värme och fuktighet. Dessa resultat kombinerat med hög densitet av aragonitnålar i samma prover indikerar att sedimenten späddes ut med material som svämmade över från den intilliggande grunda karbonatplattformen, vilket är jämförligt med de vitningshändelser som har observerats i dagens Bahamas. En minskning i abundans av Gephyrocapsa caribbeanica vid 240 ka kan kopplas till tidpunkten för deras senaste gemensamma förekomst (LCO) inom MIS 7. Den efterföljande övergången till Gephyrocapsa oceanica som den dominerande stora arten kan indikera en ekologisk ersättning av G. caribbeanica, eller indikera varmt vatten med låg salthalt.

Os bisfosfonatos representam uma classe de drogas que agem sobre o metabolismo ósseo e são amplamente utilizadas na prevenção e tratamento de estados osteopênicos e osteoporóticos. Os objetivos do presente estudo foram avaliar, in vivo, o efeito do uso sistêmico de alendronato sódico: na densidade mineral óssea de ratos, por meio da densitometria óptica radiográfica e da técnica de absortometria radiológica de dupla energia (DXA); e nas estruturas dentárias mineralizadas de incisivos murinos, por meio da espectrometria na região do infravermelho, espectroscopia de fluorescência, microdureza transversal, microscopia eletrônica de varredura e microscopia de luz polarizada. Foram utilizados 45 ratos Wistar, com 36-42 dias de idade, pesando em média 200-230g, os quais foram divididos em dois grupos: experimental (n= 25) e controle (n= 20). No grupo experimental foram administradas duas doses semanais de 1mg/Kg de alendronato de sódio quimicamente puro diluído em água destilada, via gavagem, enquanto que os animais do grupo controle receberam apenas água destilada. Decorrido o período de 60 dias, os animais foram mortos por sobredose anestésica e, em seguida, foram extraídos os incisivos superiores e removidas as tíbias. As tíbias foram submetidas à avaliação da densidade mineral óssea por meio de análise radiográfica e da técnica de absortometria radiológica de dupla energia (DXA). Os incisivos superiores foram submetidos às seguintes avaliações: análise química por espectrometria na região do infravermelho e espectroscopia de fluorescência, microdureza transversal do esmalte e da dentina; microscopia eletrônica de varredura e microscopia de luz polarizada. Os resultados numéricos obtidos foram submetidos à análise estatística por meio do teste não-paramétrico de Kruskal-Wallis, utilizando o software SAS (Statistical Analysis System) for Windows versão 9.1.3. O nível de significância adotado foi de 5%. O grupo experimental apresentou valores de densidade mineral óssea superiores (p<0,05) em relação ao grupo controle, pelos métodos da densitometria óptica radiográfica e DXA. A análise química pelos métodos de espectrometria na região do infravermelho e espectroscopia de fluorescência permitiu detectar a presença do alendronato na estrutura dentária mineralizada do grupo experimental e que a porcentagem dessa incorporação foi de 0,0018% por elemento dental. Os resultados da microdureza transversal do esmalte e da dentina não revelaram diferença estatisticamente significante entre os grupos experimental e controle (p>0,05). Não foram observadas diferenças morfológicas significativas entre as amostras de ambos os grupos por meio da análise por microscopia eletrônica de varredura e microscopia de luz polarizada. Com base nos resultados obtidos, conclui-se que o tratamento com alendronato sódico provocou aumento na densidade mineral óssea da metáfise proximal da tíbia e que o alendronato incorporou-se nas estruturas dentárias mineralizadas, porém sem provocar efeitos significativos na microdureza e na morfologia do esmalte e da dentina de incisivos de ratos. / Bisphosphonates represent a class of drugs that act on bone metabolism and are widely used in the prevention and treatment of osteopenic and osteoporotic states. The objectives of this study were to evaluate, in vivo, the effect of the systemic use of sodium alendronate on: the mineral bone density of rats, by radiographic optical densitometry and dual-energy x-ray absorptiometry (DXA); the mineralized dental structures of murine incisors, by analysis of infrared (IR) spectrometry, fluorescence spectroscopy, cross-sectional microhardness (CSMH), scanning electron microscopy (SEM) and polarized light microscopy (PLM). Forty-five Wistar rats aged 36-42 days and weighing 200-230 g were assigned to two groups: experimental (n= 25) and control (n= 20). The experimental group received two weekly doses of 1 mg/kg of chemically pure sodium alendronate diluted in distilled water, via gavage, while the animals of the control group received only distilled water. After 60 days, the animals were killed by anesthetic overdose, and the maxillary incisors were extracted and the tibias were removed. The mineral bone density of the tibias was analyzed radiographically and by DXA. The maxillary incisors were subjected to the following evaluations: chemical analysis by IR spectrometry and fluorescence spectroscopy, enamel and dentin CSMH, SEM and PLM. The results were subjected to statistical analysis by the Kruskal-Wallis non-parametric test, using the SAS (Statistical Analysis System) software for Windows version 9.1.3. The significance level was set at 5%. The experimental group presented higher mineral bone density (p<0.05) than the control group, by radiographic optical densitometry and DXA. The chemical analysis by IR spectrometry and fluorescence spectroscopy revealed the presence of alendronate in the mineralized dental structure of the specimens of the experimental group, with a percentage of incorporation of 0.0018% per tooth. The results of enamel and dentin CSMH did not show statistically significant difference between the experimental and control groups (p>0.05). There were no significant morphological differences among the specimens of the groups by SEM and PLM. Based on the obtained results, it may be concluded that the treatment with sodium alendronate caused an increase in the mineral bone density of the proximal tibial metaphysis, and that alendronate was incorporated in the mineralized dental structures without causing significant effects in the enamel and dentin microhardness and morphology of rat incisors.

Le dichroïsme circulaire de photoélectrons (PECD) se manifeste par une intense asymétrie avant/arrière dans la distribution angulaire de photoélectrons selon l’axe des photons, lors de la photoionisation d’un énantiomère pur de molécule chirale en phase gazeuse par un rayonnement polarisé circulairement. Cette thèse est consacrée à l’étude de ce phénomène, avec le synchrotron de la ligne DESIRS, sur différents systèmes chiraux allant de molécules libres (composés bromés, alanine) aux agrégats de glycidol et aux complexes formés avec l’eau. Pour ce faire, des mesures expérimentales menées à l’aide du spectromètre double imageur à coïncidence électron/ion DELICIOUS 3 ont été couplées à des calculs théoriques (CMS-Xα). Le chapitre 1 introduit les concepts fondamentaux nécessaires à l’étude de la chiralité en physique et le chapitre 2 présente les méthodes expérimentales et théoriques mises en œuvre. Le chapitre 3 détaille les résultats obtenus sur des composés chiraux halogénés : l’acide bromo-propionique (BPA) et les isomères 1,3- et 1,4-bromo-phényléthylamine (BrPhEtA). La sensibilité du PECD à l’isomérie, de même que le rôle de la localisation de l’orbitale initiale par rapport au centre chiral sont au cœur de cette étude. Le PECD du plus simple acide aminé chiral protéique, l’alanine, produit par chauffage résistif et par thermo-désorption d’aérosol, est présenté au chapitre 4 avec une étude conformationnelle selon la température conduisant à une distribution plausible des conformères. Ces résultats sont ensuite discutés dans le contexte de l’homochiralité de la vie (i.e. le fait que les acides aminés sont tous de type L dans la biosphère), le PECD étant un processus photophysique asymétrique pouvant induire un enrichissement énantiomérique. Le chapitre 5 s’intéresse au PECD sur des systèmes plus complexes : les agrégats de glycidol et les complexes de glycidol et d’eau. Une simple sélection en masse permet de mettre en évidence un effet spectaculaire de l’agrégation sur le PECD observé. DELICIOUS 3 permet ensuite d’éliminer des processus en cascade par une sélection en taille des neutres natifs. / Photoelectron Circular Dichroism (PECD) is observed as a forward/backward asymmetry, with respect to the photon axis, of the photoelectron angular distributions resulting from the circularly polarized light-induced photoionization of gas phase pure enantiomers of chiral species. This thesis is devoted to the study, with the synchrotron of the DESIRS beamline, of this phenomenon on different chiral systems from free molecules (bromine compounds, alanine) to glycidol clusters and water-glycidol complexes. Chapter 1 introduces the fundamental concepts required for the study of chirality in physics and chapter 2 presents the experimental and theoretical methods which have been used. Chapter 3 gives details concerning the results on the halogenated chiral compounds: bromopropionic acid (BPA) and 1,3- and 1,4-bromo-phenylethylamine isomers (BrPhEtA). The sensitivity of PECD to isomerism as well as the role of the localization of the initial orbital of the outgoing electron with respect to the chiral center is at the core of this study. The PECD of the simplest proteic chiral amino acid, alanine, produced by resistive heating and thermodesorption of an aerosol, is introduced in chapter 4 with a conformational study depending on temperature, leading to a plausible conformer distribution. These results are then discussed in the context of homochirality of life (i.e. the fact that only L-amino acids are found in the biosphere) as PECD is an asymmetric photophysical processes which can induce an enantiomeric enrichment. Chapter 5 is focused on PECD in systems of greater complexity: glycidol clusters and water-glycidol complexes. A simple mass selection enables to unravel a spectacular clustering effect on the observed PECD and the use of DELICIOUS 3 enables then to remove any cascading processes thanks to a size selection of nascent species.

Os bisfosfonatos representam uma classe de drogas que agem sobre o metabolismo ósseo e são amplamente utilizadas na prevenção e tratamento de estados osteopênicos e osteoporóticos. Os objetivos do presente estudo foram avaliar, in vivo, o efeito do uso sistêmico de alendronato sódico: na densidade mineral óssea de ratos, por meio da densitometria óptica radiográfica e da técnica de absortometria radiológica de dupla energia (DXA); e nas estruturas dentárias mineralizadas de incisivos murinos, por meio da espectrometria na região do infravermelho, espectroscopia de fluorescência, microdureza transversal, microscopia eletrônica de varredura e microscopia de luz polarizada. Foram utilizados 45 ratos Wistar, com 36-42 dias de idade, pesando em média 200-230g, os quais foram divididos em dois grupos: experimental (n= 25) e controle (n= 20). No grupo experimental foram administradas duas doses semanais de 1mg/Kg de alendronato de sódio quimicamente puro diluído em água destilada, via gavagem, enquanto que os animais do grupo controle receberam apenas água destilada. Decorrido o período de 60 dias, os animais foram mortos por sobredose anestésica e, em seguida, foram extraídos os incisivos superiores e removidas as tíbias. As tíbias foram submetidas à avaliação da densidade mineral óssea por meio de análise radiográfica e da técnica de absortometria radiológica de dupla energia (DXA). Os incisivos superiores foram submetidos às seguintes avaliações: análise química por espectrometria na região do infravermelho e espectroscopia de fluorescência, microdureza transversal do esmalte e da dentina; microscopia eletrônica de varredura e microscopia de luz polarizada. Os resultados numéricos obtidos foram submetidos à análise estatística por meio do teste não-paramétrico de Kruskal-Wallis, utilizando o software SAS (Statistical Analysis System) for Windows versão 9.1.3. O nível de significância adotado foi de 5%. O grupo experimental apresentou valores de densidade mineral óssea superiores (p<0,05) em relação ao grupo controle, pelos métodos da densitometria óptica radiográfica e DXA. A análise química pelos métodos de espectrometria na região do infravermelho e espectroscopia de fluorescência permitiu detectar a presença do alendronato na estrutura dentária mineralizada do grupo experimental e que a porcentagem dessa incorporação foi de 0,0018% por elemento dental. Os resultados da microdureza transversal do esmalte e da dentina não revelaram diferença estatisticamente significante entre os grupos experimental e controle (p>0,05). Não foram observadas diferenças morfológicas significativas entre as amostras de ambos os grupos por meio da análise por microscopia eletrônica de varredura e microscopia de luz polarizada. Com base nos resultados obtidos, conclui-se que o tratamento com alendronato sódico provocou aumento na densidade mineral óssea da metáfise proximal da tíbia e que o alendronato incorporou-se nas estruturas dentárias mineralizadas, porém sem provocar efeitos significativos na microdureza e na morfologia do esmalte e da dentina de incisivos de ratos. / Bisphosphonates represent a class of drugs that act on bone metabolism and are widely used in the prevention and treatment of osteopenic and osteoporotic states. The objectives of this study were to evaluate, in vivo, the effect of the systemic use of sodium alendronate on: the mineral bone density of rats, by radiographic optical densitometry and dual-energy x-ray absorptiometry (DXA); the mineralized dental structures of murine incisors, by analysis of infrared (IR) spectrometry, fluorescence spectroscopy, cross-sectional microhardness (CSMH), scanning electron microscopy (SEM) and polarized light microscopy (PLM). Forty-five Wistar rats aged 36-42 days and weighing 200-230 g were assigned to two groups: experimental (n= 25) and control (n= 20). The experimental group received two weekly doses of 1 mg/kg of chemically pure sodium alendronate diluted in distilled water, via gavage, while the animals of the control group received only distilled water. After 60 days, the animals were killed by anesthetic overdose, and the maxillary incisors were extracted and the tibias were removed. The mineral bone density of the tibias was analyzed radiographically and by DXA. The maxillary incisors were subjected to the following evaluations: chemical analysis by IR spectrometry and fluorescence spectroscopy, enamel and dentin CSMH, SEM and PLM. The results were subjected to statistical analysis by the Kruskal-Wallis non-parametric test, using the SAS (Statistical Analysis System) software for Windows version 9.1.3. The significance level was set at 5%. The experimental group presented higher mineral bone density (p<0.05) than the control group, by radiographic optical densitometry and DXA. The chemical analysis by IR spectrometry and fluorescence spectroscopy revealed the presence of alendronate in the mineralized dental structure of the specimens of the experimental group, with a percentage of incorporation of 0.0018% per tooth. The results of enamel and dentin CSMH did not show statistically significant difference between the experimental and control groups (p>0.05). There were no significant morphological differences among the specimens of the groups by SEM and PLM. Based on the obtained results, it may be concluded that the treatment with sodium alendronate caused an increase in the mineral bone density of the proximal tibial metaphysis, and that alendronate was incorporated in the mineralized dental structures without causing significant effects in the enamel and dentin microhardness and morphology of rat incisors.

Polymeric materials have provided pathways to products that could not be manufactured otherwise. A new technology which merges the benefits of ceramics into these polymer products has created materials ideally suited to many different industries, like food packaging. Nano Scale Surface Systems, Inc. (NS3), a company which coats polymers with ceramic oxides like SiO2 through a process known as plasma enhanced chemical vapor deposition (PECVD), was interested in the feasibility of an in line measurement system for monitoring the deposited films on various polymer products. This project examined two different coated polymer products, polyethylene terephthalate (PET) beverage containers and biaxially oriented PET food packaging, commonly known as plastic wrap in an effort to determine the feasibility of an ellipsometry based measurement system for NS3’s purpose. Due to its extensive use in the semiconductor industry for monitoring films deposited on silicon, a measurement systems known as ellipsometry, adept at monitoring the thickness and refractive index of thin films deposited on various substrates, appeared to be an ideal system for the measurement of ceramic oxides deposited on various polymer substrates. This project set out to determine the feasibility of using an ellipsometry based measurement system to monitor ceramic films, specifically silicon oxides (SiOX), deposited on polymer products. A preliminary experiment determined linearly polarized light could induce a discernible change in polarized light traversing a coated beverage container relative to an uncoated container. However, the experiment lacked repeatability due to the measurement apparatus’ cheap setup, prompting the construction of a null (conventional) ellipsometer for further research. The curved surface of the beverage containers under study unnecessarily complicated the feasibility study so further research examined PECVD SiOX on biaxially oriented PET instead. Characterization of the PECVD SiOX-PET material was divided into three experiments, with the first two analyzing the SiOX film and PET substrate separately while the third analyzed them together. To assist with the characterization experiments, NS3 provided samples, both SiOX coated and uncoated, of various deposition thicknesses on silicon and biaxially oriented PET substrates. Null ellipsometry was used in conjunction with spectroscopic reflectometry to characterize the refractive index and thickness of the deposited films. The combined measurement systems found the refractive index of the deposited SiOX films to be between 1.461 and 1.465. The measured thicknesses resulting from the two measurement systems coincided well and were usually 10-20 nm thicker than the predicted thicknesses by the deposition processing parameters. Abeles’ method and monochromatic goniometry were attempted; however, the results had to be discarded due to irrecoverable errors discovered in the reflectance measurement. X-ray photoelectron spectroscopy (XPS) data provided by NS3 showed the deposited SiOX films to be homogeneous with stoichiometries between 2.15 and 2.23. Characterization of the uncoated biaxially oriented PET required numerous measurement systems. From spectroscopic transmission, trirefringent anisotropy was discovered, intertwined with thickness variations in the PET foil. Goniometry measurements displayed distinct interference curves resulting from rear interface reflections interfering with front interface reflections from the PET sample. Subsequent goniometric models produced multiple solutions due to an unknown optical phenomenon, probably scattering, which degraded the reflection measurements. However, a combined measurement technique utilizing goniometry and differential scanning calorimetry (DSC) determined the refractive indices of the polymer to be NX = 1.677, NY = 1.632 and NZ = 1.495 with a thickness of 11.343 μm and a volume fraction crystallinity of 35-41%. Utilizing the measured refractive indices, ellipsometric models produced only an adequate fit of the measured data due to the presence of depolarization caused by non-uniform PET thickness and scattering resulting from embedded microscopic crystallites. The majority of the error in the ellipsometric data was observed in the Δ measurement. XPS measurements of SiOX deposited on polypropylene (PP) provided by NS3 showed a heterogeneous interphase layer between the deposited oxide and the polymer substrate where the composition of the layer was continually changing. A similar region, which violates the homogenous assumption the ellipsometric model relied on, was anticipated for the SiOX-PET samples under investigation. The use of an effective medium approximation (EMA) to represent the interphase region was attempted, but failed to provide a decent model fit of the measured data. Depolarization and high optical anisotropy caused by the polymer substrate in combination with a heterogeneous interphase region and the effects of the deposited SiOX layer all interacted to prevent ellipsometric modelling of the null ellipsometry measurements conducted. Goniometry measurements were conducted on the thickest deposited SiOX film (approximately 100 nm) which allowed for the refractive index of the film to be approximated through Abeles’ method (n = 1.46); however the validity of this approximation was questionable given the presence of interference fringes resulting from interference between reflections at both the front and rear interfaces of the material. From the experiments conducted, it was concluded that null ellipsometry with conventional ellipsometric models could not adequately measure a SiOX film’s refractive index or thickness when deposited on biaxially oriented PET. The reasons for the failure were interactions between multiple sources of error which led to both measurement errors and inaccurate model assumptions. Use of generalized ellipsometry, possibly with spectroscopic ellipsometry, may overcome the failures of conventional ellipsometry when studying this complex optical material.

La plupart des maladies cardio-vasculaires sont étroitement liées à l’architecture 3D des faisceaux de cardiomyocytes du myocarde humain. Connaitre en détail cette architecture permet de lever un verrou scientifique sur l’organisation spatiale complexe des faisceaux de cardiomyocytes, et offre des pistes pour trouver des solutions pertinentes permettant de guérir ces maladies. A cause de la nature biréfringente des filaments de myosine qui se trouvent dans les cellules cardiomyocyte, l’Imagerie en Lumière Polarisée (ILP) se révèle comme la seule méthode existante permettant d’étudier en détail, l’architecture et l’orientation des faisceaux de cardiomyocytes au sein de la masse ventriculaire. Les filaments de myosine se comportent comme des cristaux uni-axiaux biréfringents, ce qui permet de les modéliser comme les cristaux uni-axiaux biréfringents. L’ILP exploite les propriétés vibratoires de la lumière car l’interaction photonique et atomique entre la lumière et la matière permet de révéler l’organisation structurelle et l’orientation 3D des cardiomyocytes. Le présent travail se base sur la modélisation des différents comportements de la lumière après avoir traversé des faisceaux de cardiomyocytes. Ainsi, un volume 100×100×500 µm3 a été décomposé en plusieurs éléments cubiques qui représentent l'équivalent de l'intersection des cellules de diamètre de 20 µm chacune. Le volume a été étudié dans différentes conditions imitant l’organisation 3D des cardiomyocytes dans différentes régions du myocarde. Les résultats montrent que le comportement du volume change suivant l’arrangement spatial des cardiomyocytes à l’intérieur du volume. Grâce à un modèle analytique développé à l’aide des simulations, il a été possible de connaitre en tout point, l’orientation 3D des cardiomyocytes dans tout le volume. Ce modèle a été implémenté dans un greffon logiciel. Puis, il a été validé avec les piliers des valves auriculo-ventriculaire en comparant les courbes obtenues en simulation numérique à celles obtenues dans la phase expérimentale. De plus, il a été possible de mesurer l’orientation 3D des faisceaux de cardiomyocytes à l’intérieur du pilier. Après cette validation, le modèle a été utilisé sur un cœur humain (sain) en entier. Puis, nous avons extrait les cartographies des orientations 3D (angle azimut, angle d’élévation) des cardiomyocytes, ainsi que la cartographie des niveaux d’homogénéité du myocarde en entier. Pour une confrontation qualitative des mesures de l’orientation 3D obtenues en ILP avec celles en IRM, un cœur humain sain d’un enfant de 14 mois a été prélevé lors de l’autopsie, fixé dans du formol, puis imagé en entier par IRM puis en ILP. Malgré la faible résolution des images en IRM, les résultats obtenus montrent que les mesures de l’orientation 3D des cardiomyocytes issues de ces deux méthodes d’imageries se révèlent quasiment identiques. / Most cardiovascular diseases are closely linked to the 3D cardiomyocytes bundles of the human myocardium. Knowing in detail this architecture allows us to overcome a scientific bottleneck on the complex spatial organization of cardiomyocytes, and offers ways to find appropriate solutions to treat these diseases. The goal of present thesis is then to develop methods and techniques that allow gaining insights into the geometric arrangement of cardiomyocytes or cardiomyocytes bundles in the myocardium. Due to the birefringent nature of myosin filaments that are found in myocardial cells, the Polarized Light Imaging (PLI) appears as the only existing method for studying in detail the architecture and cardiomyocytes bundle orientation in ventricular mass. Myosin filaments react as uniaxial birefringent crystal; thereby it has been modeled as the uniaxial birefringent crystal. The PLI uses the vibration properties of light; the photonic and atomic interaction between light and matter can reveal the structural organization and the 3D cardiomyocytes orientation of the myocardium. The present work is based on modeling the behavior of the light after passing through a cardiomyocytes bundle. Thus, a volume 100 × 100 × 500 μm3 has been decomposed in a number of cubic elements which are equivalent to cardiac cells of diameter of 20 microns. The volume was studied under different conditions to emulate the organization of cardiomyocytes in different regions in human myocardium: isotropic region, heterogeneous region, region with cardiomyocytes bundle crossing. The results showed that the behavior of the volume changes according to the spatial arrangement of cardiomyocytes within the volume. Through an analytical model developed using simulation, it has been possible to know the 3D orientation of cardiomyocytes at any region throughout the volume. This model has been implemented in software as a plugin. Then, it has been validated with the pillars of atrio-ventricular valves by comparing the curves obtained by numerical simulation with those obtained in the experimental phases. Moreover, it has been possible to measure the 3D orientation of cardiomyocytes bundles within the pillars. After validation, the model was applied to an entire human healthy heart. Then, we extracted the mapping of the 3D orientations (azimuth angle, elevation angle) of cardiomyocytes bundles, as well as the mapping of the homogeneity levels of the entire myocardium. For a qualitative comparison of the 3D orientation measurements obtained with the PLI and Magnetic Resonance Imaging (MRI), the healthy human heart of a 14 month old child was extracted at autopsy, then fixed in formalin, and finally imaged by MRI and PLI. Despite the low spatial resolution of MRI images, the results showed that the 3D orientations of cardiomyocytes bundles measured from these two imaging methods appeared almost identical.