In barley, the GPC (Grain Protein Content) has proved to be of great importance for both feed, food and beer production. When it comes to feed and food, a high GPC is desirable since it indicates good nutritional values, while in beer production a low and stable GPC is needed to avoid beer chill haze. In previous studies a decrease in the GPC has been seen in different accessions of barley developed at different time periods during the last 100 years. The gene family HvNAM, including the genes HvNAM1 and HvNAM2, has in previous studies been shown to be important for the remobilization of nutrients towards the grains during the senescence and thus also for the GPC. In this study, 40 Nordic accessions from different improvement groups from the end of the 19th century until today have been analyzed for polymorphism in those genes. Statistical analyses has been conducted to investigate if there are any associations between the polymorph nucleotide positions and the nutritional values of grain protein, iron and zinc contents. However, no such associations were found. Instead some correlations could be seen between the nutrient content and thousand grain weight, a relative measurement of the grain size. In conclusion, since no polymorphisms were found to be associated to the nutritional value there might instead be a correlation between the gene expression and the nutritional value. Future work should thus focus on the gene expression of HvNAM1 and HvNAM2 in Nordic accessions of barley.

In the effort to design new photochromic material for integral parts in many scientific processes I have synthesized, characterized and studied photophysical characteristics of new photochromic polymers. By coupling the properties of a photochromic unit with that of polymers one can anticipate the discovery of new viable photochromic materials that has the possibility to enhance the processes in many scientific fields. Water solubility in photochromic processes gives life to new innovations and possibilities in the scientific community. As part of my dissertation I have designed, synthesized and studied new water soluble photochromic polymers. The findings in this dissertation will help to reveal the understandings of incorporating/coupling a photochromic molecule with that of polymers.

La glycogène phosphorylase (GP) est l'enzyme clé de la mobilisation du glycogène dans les cellules. Chez l'homme, cette enzyme est retrouvée sous trois isoformes dont une cérébrale (GPc). Ces trois enzymes allostériques sont régulées à la fois par fixation d'effecteurs, et par phosphorylation. Cependant, bien que très similaires, la GPc présentent des caractéristiques de régulation qui lui sont propres. Par ailleurs, la GPc possède dans sa séquence plusieurs résidus cystéines réactifs suggérant que celle-ci peut être soumise à une régulation par les espèces réactives de l'oxygène (EROs). L'objectif de ce travail a donc été d'étudier les mécanismes moléculaires et cellulaires de la régulation de la GPc. Dans un premier temps, nous avons déterminé la structure de la GPc jusqu'à présent inconnue. Ces analyses ont permis de mettre en évidence les bases structurales de la régulation de la GPc par ses effecteurs allostériques. Nous nous sommes ensuite intéressés à la régulation de cette enzyme par le H2O2. Grâce à des approches de biochimie et de biologie cellulaire, nous avons montré que le H2O2 induit la formation d'un pont disulfure intramoléculaire au niveau du site de fixation de l'AMP, empêchant l'activation de cette enzyme par son effecteur allostérique. Cette régulation, spécifique de la GPc, permet un contrôle de la glycogénolyse par phosphorylation uniquement, en condition oxydante. Enfin, nous avons mis en évidence la capacité de composés environnementaux électrophiles (pesticides) à détourner la régulation redox de la GPc, conduisant à une altération du métabolisme du glycogène et pouvant ainsi participer au développement de pathologies neurodégénératives / Glycogen phosphorylase (GP) is the key enzyme for glycogen mobilization in cells. I human, this enzyme is found as three isoforms : liver GP (lGP), muscle GP (mGP) and brain GP (bGP). These three enzymes are allosteric enzymes, regulated by both the binding of allosteric effectors and phosphorylation. However, despite GPs are highly similar, bGP display distinguishing features. In addition, highly reactive cysteine residues are found in the primary sequence of bGP, suggesting that this enzyme might be regulated by reactive oxygen species (ROS). As a consequence, we investigated the molecular and cellular regulation of the bGP. First, we determined the crystal structure of this enzyme, so far unknown. These data revealed the structural bases of bGP regulation by its allosteric effectors, leading to the activation and the inactivation of the enzyme. We then focused on the regulation of bGP by H2O2, a model of ROS. Using biochemical and cellular approaches, we showed that H2O2 induces the formation of an intramolecular disulfide bond in the AMP binding site of the enzyme, avoiding its regulation by the allosteric effectors, without affecting its regulation by phosphorylation. Under oxidative condition, this regulation, unique to the brain form of GP, allows a control of the glycogenolysis through phosphorylation only. Finally, we demonstrated that electrophilic compounds from the environment (pesticides) might divert the redox regulation of bGP, leading to the alteration of glycogen metabolism which could participate to the development of neurodegenerative diseases

In science and engineering research, filtering or estimation of system’s states is widely used and developed, so the structure of a new nonlinear filter is proposed. This thesis focuses on the procedures of propagation and update step of the new filter. The algorithms used in the filter, including generalized Polynomial Chaos Algorithms, Markov Chain Monte Carlo algorithms, and Gaussian Mixture Model algorithms, are introduced. Then, the propagation and update step of the proposed filter are applied in solving two nonlinear problems: Van der Pol Oscillator and Two Body System. The simulation shows that the results of the propagation and update step are reasonable and their designs are valuable for further tests. The propagation step has the same accuracy level compared with a Quasi Monte Carlo simulation while using a much smaller number of points. The update step can build a useful Gaussian Mixture Model as the posterior distribution.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

A multidisciplinary literature survey revealed that copolymeric nanoparticles could be applied in various technologies such as the production of paint, adhesives, packaging material and lately especially drug delivery systems. The specialized application and investigation of copolymers in drug delivery resulted in the synthesis of two series of copolymeric materials, i.e. poly(styrene-co-methyl methacrylate) (P(St-co-MMA)) and poly(styrene-co-ethyl methacrylate) (P(St-co-EMA)) were synthesized via the technique of o/w microemulsion copolymerization. These copolymers have not as yet been utilized to their full potential in the development of new drug delivery systems. However the corresponding hydrophobic homopolymer poly(styrene) (PS) and the hydrophilic homopolymer poly(methyl methacrylate) (PMMA) are known to be biocompatible. Blending of homopolymers could result in novel applications, however is virtually impossible due to their unfavorable mixing entropies. The immiscibility challenge was overcome by the synthesis of copolymers that combined the properties of the immiscible homopolymers. The synthesized particles were analyzed by gel permeation chromatography combined with multi-angle laser light scattering (GPC-MALLS) and attenuated total reflectance Fourier infrared spectroscopy (ATR-FTIR). These characterizations revealed crucial information to better understand the synthesis process and particle properties i.e. molecular weight, nanoparticle size and chemical composition of the materials. Additionally, GPC-MALLS revealed the copolymer chain conformation. These characterizations ultimately guided the selection of appropriate copolymer nanoparticles to develop a controlled-release drug delivery system. The selected copolymers were dissolved in a pharmaceutically acceptable solvent, tetrahydrofuran (THF) together with a drug, rifampin. Solvent casting of this dispersion resulted in the evaporation of the solvent and assembly of numerous microscale copolymer capsules. The rifampin molecules were captured in these microcapsules through a process of phase separation and coacervation. These microcapsules finally sintered to produce a multi-layer film with an unusual honeycomb structure, bridging yet another size scale hierarchy. Characterization of these delivery systems revealed that both series of copolymer materials produced films capable of controlling drug release and that could also potentially prevent biofilm adhesion. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.

Absorbed dose distributions in lineal energy for neutrons and gamma rays were measured by using both a tissue-equivalent walled counter (TEPC) and a graphite-walled low pressure proportional counter (GPC) in the Am-Be neutron source facility at UOIT. A series of measurements were performed with the counters filled with propane-based TE gas (55.1% C3H8, 39.5% CO2 and 5.4% N2) at operating gas pressures corresponding to tissue spheres 2.0 , 4.0 and 8.0 μm in diameter. The results of these measurements indicated satisfactory performance of counters to measure microdosimetric spectra extending down to event-sizes that cover the gamma component of a mixed field. The spectra and the related mean values ̅y F and ̅y D are compared with other similar work but with monoenergetic neutrons of different energy range, the agreement between them is good. An assessment of the performance of different size TEPC has been done. An excellent agreement between their event size spectra was found and the proton edge appears at the same position on the lineal energy scale and differences in microdosimetric parameters ̅ and ̅ is not exceeding 3%, which is in the region of counting statistics. In Am-Be neutron field, the efficiency of the TEPCs was measured to have an average value of 250 counts per μSv or equivalently about 4.17 counts per minutes per μSv/hr. This efficiency is reasonable for dose equivalent measurements but needs a long integration period. The measurements showed that the dose equivalent which depends on the measurement of energy deposition by the secondary charged particles was originated mainly from elastic collisions of the incident neutrons with hydrogen atoms. Moreover the number of events in the sensitive gas is dominated by proton recoils. A non- negligible fraction of the dose equivalent resulted from gamma interactions, alpha and recoil nuclei. The energy deposition patterns in these micro-scale targets are strongly dependent on radiation quality, so differences of linear energy transfer (LET) of the components in a mixed radiation field are significant. Accordingly, in a radiation field with an unknown gamma ray energy spectrum, absorbed dose for neutrons can be obtained by the separation of neutron induced events from gamma events using their distribution in lineal energy. To separate neutron dose from gamma dose a simple lineal energy threshold technique has been used in addition to a more sophisticated methods using γ-fitting and the graphite-walled counter measurements. The results of this study will establish the degree of error introduced by using a lineal energy threshold, which is likely to be used in any hand-held neutron monitor based on TEPCs. / UOIT

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

A multidisciplinary literature survey revealed that copolymeric nanoparticles could be applied in various technologies such as the production of paint, adhesives, packaging material and lately especially drug delivery systems. The specialized application and investigation of copolymers in drug delivery resulted in the synthesis of two series of copolymeric materials, i.e. poly(styrene-co-methyl methacrylate) (P(St-co-MMA)) and poly(styrene-co-ethyl methacrylate) (P(St-co-EMA)) were synthesized via the technique of o/w microemulsion copolymerization. These copolymers have not as yet been utilized to their full potential in the development of new drug delivery systems. However the corresponding hydrophobic homopolymer poly(styrene) (PS) and the hydrophilic homopolymer poly(methyl methacrylate) (PMMA) are known to be biocompatible. Blending of homopolymers could result in novel applications, however is virtually impossible due to their unfavorable mixing entropies. The immiscibility challenge was overcome by the synthesis of copolymers that combined the properties of the immiscible homopolymers. The synthesized particles were analyzed by gel permeation chromatography combined with multi-angle laser light scattering (GPC-MALLS) and attenuated total reflectance Fourier infrared spectroscopy (ATR-FTIR). These characterizations revealed crucial information to better understand the synthesis process and particle properties i.e. molecular weight, nanoparticle size and chemical composition of the materials. Additionally, GPC-MALLS revealed the copolymer chain conformation. These characterizations ultimately guided the selection of appropriate copolymer nanoparticles to develop a controlled-release drug delivery system. The selected copolymers were dissolved in a pharmaceutically acceptable solvent, tetrahydrofuran (THF) together with a drug, rifampin. Solvent casting of this dispersion resulted in the evaporation of the solvent and assembly of numerous microscale copolymer capsules. The rifampin molecules were captured in these microcapsules through a process of phase separation and coacervation. These microcapsules finally sintered to produce a multi-layer film with an unusual honeycomb structure, bridging yet another size scale hierarchy. Characterization of these delivery systems revealed that both series of copolymer materials produced films capable of controlling drug release and that could also potentially prevent biofilm adhesion. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.