In this study, organic and polymeric fluorophores based on 2,4,6-triphenylpyridiene (TPP) structure were found to have the novel aggregation-induced emission enhancement (AIEE) property. For the small-mass fluorophores, TPP and cyano-functionalized TPP (TPP-CN) were prepared from the facile Chichibabin reaction and their AIEE properties were characterized by the emission behavior in solvent/nonsolvent pair. Solid samples of TPP and TPP-CN exhibit enhanced emission with increasing annealing time under solvent vapors, thus, both compounds have the characters of crystallization-induced emission enhancement (CIEE) behavior. For polymeric system, copolymers PTPPF containing alternative TPP and 9,9-dioctylfluorene units were prepared through Suzuki coupling and study on its fluorescence behavior also reveals its AIEE feature. The rigid polymer possesses high emission intensity in its dilute solution state and remains almost unchanged with increasing nonsolvent fraction. The solid sample was found to have a high quantum yield (ФF) of 70 %.

With various new alternatives of low-cost sensor devices, there is a strong demand for large scale wireless sensor networks (WSN). Energy efficiency in routing is crucial for achieving the desired levels of longevity in these networks. Existing routing algorithms that do not combine information on transmission energies on links, residual energies at nodes, and the identity of data itself, cannot reach network capacity. A proof-of-concept routing algorithm that combines data aggregation with the minimum-weight path routing is studied in this thesis work. This new algorithm can achieve much larger network lifetime when there is redundancy in messages to be carried by the network, a practical reality in sensor network applications.

Understanding the differential bonding mechanics underlying bleeding disorders is of crucial importance to human health. In this research insight is provided into how four of these bleeding disorders (each with somewhat similar clinical characteristics), work at the molecular bond level. The bleeding diseases studied here can result from defects in the platelet glycoprotein (GP) Ibα the von Willebrand factor (vWF) molecule, or the ADAMTS-13 enzyme. Types 2B and 2M von Willebrand Disease (VWD) result in excess bleeding, yet type 2B has increased binding affinity between platelet GPIbα and vWF, while type 2M has decreased binding affinity between these two molecules. Platelet type VWD (pt-VWD) causes mutations in the GPIbα molecule and has similar characteristics to type 2B VWD. Further, in thrombotic thrombocytopenic purpura, bleeding results when there is a lack of active ADAMTS-13 enzyme. Each disease results in patient bleeding, but due to different mechanisms. This dissertation will explore the bonding mechanics between GPIbα and vWF and how they are altered in each disease state. To observe the GPIbα-vWF bonding mechanics, rolling velocities, transient tethering lifetimes, and tether frequency were determined using a parallel plate flow chamber. Data from these experiments suggest that wt-wt interactions are force dependent and have biphasic catch-slip bonding behavior. The data show that the shear stress at which the maximum mean stop time occurs differs between gain-of-function and loss-of-function mutations. Using similar methods, we study the changes resulting from pt-VWD mutations in GPIbα, and find that the catch bond seen for wt-wt interactions is lost for these mutations. Further, the data suggest that interactions with gain-of-function GPIbα mutations may be transport rather than force dependent. Finally, how the GPIbα-vWF tether bond changes for thrombotic thrombocytopenic purpura was also investigated to show that the bond lifetime in the absence of the enzyme is increased presenting a possible rationale for why bleeding occurs in this disease. Overall, the data show how the bonding mechanics of the GPIbα-vWF tether bond differ in four bleeding diseases. Further, these observations offer potential explanations for how these changes in the bonding mechanism may play a role in the observed patient bleeding.

Durch die Vielzahl von heterogenen Informationsquellen sehen sich viele Nutzer einer kaum überschaubaren Informationsflut gegenüber. Aus diesem Grund werden durch diese Arbeit die gängigen Nachrichtenformate analysiert und der aktuelle Stand der Technik im Bereich der Nachrichtenaggregatoren dargelegt. Dabei werden diese Analysen immer mit Blick auf die Möglichkeiten einer personalisierten Filterung der Inhalte durchgeführt. Anschließend wird eine im Rahmen dieser Arbeit entstandene Infrastruktur für die Aggregation, personalisierte Filterung und kollaborative Empfehlung von Inhalten aus heterogenen Nachrichtenquellen vorgestellt. Dabei wird detailiert auf die zu Grunde liegenden Konzepte eingegangen und deren praktische Umsetzung beschrieben.

No description available.

L'étude de l'influence des pharmacocinétiques de la mTHPC dans la tumeur, le plasma et les leucocytes sur la réponse à la PDT a montré que l'accumulation du photosensibilisant dans les leucocytes exhibaient une bonne corrélation avec l'efficacité de la PDT. Ces résultats suggèrent que les leucocytes pourraient jouer un rôle important dans le mécanisme de la PDT induisant des dommages vasculaires. L'étude de la monomérisation de la mTHPC au cours des interactions avec des protéines plasmatiques démontrent un taux lent de cinétique de désagrégation. La fraction de mTHPC agrégée à l'équilibre et le taux de désagrégation du photosensibilisant dépendent fortement de la teneur en protéines et de la température d'incubation. Les résultats ont démontré la formation d'agrégats libres à grande échelle avec une interaction forte entre les molécules du photosensibilisant. L'analyse cinétique démontre que la mTHPC est caractérisée par des taux très lents de redistribution depuis les complexes avec les protéines plasmatiques. Les faibles taux de redistribution de la mTHPC comparés aux autres photosensibilisants correspondent aux propriétés de liaisons uniques de la mTHPC. L'existence à la fois du transfert de la mTHPC par collision et par milieu aqueux a été supposée. L'étude en microscopie confocale indique des modèles de localisation diffus de la mTHPC à 3h et la formation de taches fortement fluorescentes du photosensibilisant à 24h d'incubation dans des cellules MCF. Les paramètres d'absorption, de temps de durée de vie de fluorescence et de photoblanchiment ont montré qu'à 24h d'incubation la mTHPC est beaucoup plus agrégée qu'à 3h. Le rendement de photoinactivation des cellules est environ 2 fois plus important pour le point à 3h. Une telle différence est attribuée à l'effet des différents états d'agrégation du photosensibilisant et aux interactions avec les composants cellulaires. L'étude théorique et spectroscopique de la mTHPC, la mTHPP et la mTHPBC nous a permis de définir leur structure agrégée dans des milieux aqueux À cette fin, nous avons développé une méthode semi-empirique de mécanique quantique basée sur le calcul des variations spectrales dans différents solvants. La mTHPC et la mTHPP forment des dimères linaires dans les millieux aqueux, tandis que la mTHPBC forme des dimères zigzag.

This thesis explores the complex relationship between food protein structure and digestibility. Food proteins are important nutrients that play a central role in controlling the textural properties of many foods. Processing of food proteins may alter the protein aggregate structure and digestibility. The degree of protein aggregation during food processing depends on the denaturing conditions and the presence of other food components. Sugars and lipids may contribute to protein glycation and protein cross-linking via the Maillard reaction. Furthermore, amino acid residues of food proteins may be chemically modified during processing, thereby influencing both the structure and the nutritional value of proteins. An in vitro digestibility assay was used to investigate the relationship between protein aggregate structure and protein digestibility. Raw and boiled egg whites were exposed to a wide range of conditions: pH 2 - 12, in the presence and absence of 200 mM NaCl. It was found that pH and NaCl treatment prior to in vitro digestion resulted in significantly different protein ultrastructures, but did not markedly influence protein digestibility under the tested conditions. Raw egg white was less digestible than boiled egg white under all test conditions. The inclusion of Maillard reaction partners caused protein cross-linking concurrent with a decrease in digestibility. The digestibility decreased with the reactivity of the Maillard reaction partner and with increasing heating time. Proteomic analysis, using tandem mass spectrometry, of raw and heated egg white showed an increase in hydrothermally induced amino acid modifications. In the presence of glucose and methylglyoxal, a Maillard reaction specific increase in arginine modification to hydroimidazolone was observed with increasing heating times. The observed modifications are likely to contribute to a change in the nutritional quality of egg white. Aggregation kinetics of the major egg white protein, ovalbumin, were studied by dynamic light scattering, small angle X-ray scattering, and transmission electron microscopy. Shape determination was only possible for ordered aggregates, but not for disordered aggregates. Prior to heating, ovalbumin molecules in the presence of water and glucose repelled each other in concentrated solution. The presence of NaCl shielded electrostatic repulsion, leading to early onset dimerisation and disordered aggregation upon heating. Methylglyoxal treated ovalbumin formed more ordered aggregates. The scattering of these structures was able to be fitted to cylindrical shape models showing an increase of cylinder length with time while the cylinder diameter remained near constant over 24 hours of heating. In addition, food protein derived amyloid fibril aggregates were characterised. Amyloid fibrils are a common ordered protein fold that has been linked to neurodegenerative diseases. In the recent literature, amyloid fibrils have been proposed as new functional macromolecules in proteinaceous foods because of their desirable textural properties. Food fibrils formed from whey, egg white, soy bean and kidney bean protein were tested to establish whether they are protease resistant or display toxicity to human Caco-2 cells (a model intestinal cell line). The food fibrils were compared to insulin amyloid fibrils, a well characterised amyloid system. It was shown that the food fibrils displayed some resistance towards in vitro hydrolysis and were not found to be toxic. This work contributes to the understanding of food protein aggregation and digestibility under relevant conditions. It highlights the relationship of aggregate structure and digestibility and the particular role of the Maillard reaction. Moreover, evidence is provided that food protein derived amyloid fibrils may be safe ingredients in consumables. These findings may contribute to optimising industrial food processes and creating safe new food products.

An aqueous nanoparticle dispersion is a complex fluid whose mobility in porous media is controlled by four key factors: the conditions necessary for the stability of nanoparticle dispersions, the kinetics of nanoparticle aggregation in an unstable suspension, the rheology of stable or unstable suspensions, and the interactions between the nanoparticles and oil/water interface and mineral surfaces. The challenges in controlling nanoparticle transport come from the variations of pH and ionic strength of brine, the presence of stationary and mobile phases (minerals, oil, water and gas), the geochemical complexity of reservoir rocks, and pore-network. The overall objective of this work is to achieve a better understanding of nanoparticle transport in porous media based on a systematic experimental and theoretical study of above factors. For this purpose, the critical conditions for the aqueous stability of nanoparticles are identified and fit by a theoretical model, which describes the interaction energy between silica nanoparticles. Above critical conditions nanoparticle aggregation becomes significant. A model for the aggregation kinetics is developed and validated by experiments. A mechanistic model for predicting the viscosity of stable and unstable silica nanoparticle dispersions over a wide range of solid volume fraction is developed. This model is based on the concept of effective maximum packing fraction. Adsorption experiments with silica nanoparticles onto quartz, calcite and clay surfaces and interfacial tension measurements provide insightful information on the interaction of the nanoparticles with minerals and decane/water interface. The extent of nanoparticle adsorption on mineral/water and decane/water interfaces is evaluated based on DLVO theory and Gibbs’ equation. Visual observations and analytical methods are used to understand the interaction of nanoparticles with clay. The characterization of nanoparticle behavior in bulk phases is built into an understanding of nanoparticle transport in porous media. In particular, the rheology of nanoparticle dispersions flowing through permeable media is compared with those determined using a rheometer. In the presence of residual oil, the retention of silica nanoparticles at water/oil interface during steady flow is investigated. The results from batch experiments of nanoparticle adsorption are used to explain the flow behavior of these nanoparticles in a glass bead pack at residual oil saturation. / text

The work centersaround perfluoroaryl azides (PFAAs), and theirability to undergo certain fast and robusttransformations. The chemistry was furtherappliedfor biomedical applications. The first section focuses on the azide-aldehyde-amine cycloaddition using PFAAs. Experimental and computational investigations uncovered a fast azide-enamine cycloaddition to form triazolines, which spontaneously rearrange into stable amidine products. In addition, this transformation was explored in the formulation of pure nanodrugs. Because this reaction can introduce a phenyl and a perfluoroaryl moiety enabling supramolecular interactions near the antibiotic drug, the resulting ciprofloxacin derivatives formed nano-sized aggregates by precipitation, which displayed aggregation-induced emission for bacterial imaging as well as enhanced size-dependent antibacterial efficacy. In the second section, the high electrophilicity of PFAAs was explored to transform azides to aryl amides. The reactivity of PFAAs in the thioacid/azide reaction was studied. In addition, PFAAs were discovered to react with phenylacetaldehyde to form aryl amidesviaan azide-enol cycloaddition, similar tothe perfluoroaryl azide-aldehyde-amine reaction.This strategyof amide synthesiswas furthermoregeneralized through a combination of base-catalyzed azide-enolate cycloaddition reaction and acid-or heat-promoted rearrangement of triazolines. The last section describes a type of azide fluorogens whose fluorescence can be switched on by alight-initiated intramolecular nitrene insertion intoa C-H bond in the neighboring aromaticring. These fluorogenic structures were efficiently accessed via the direct nucleophilic aromatic substitution of PFAAs. / <p>QC 20150903</p>

No description available.