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This thesis describes the examination of novel block copolymers that contain Ru(bpy)32+ complexes incorporated into one block of diblock copolymers made by ROMP. With the intent of exploring the potential usefulness of these interesting materials in applications such as light-harvesting and sensing, a systematic study of the solution self-assembly, luminescence properties, and the ability of the metal complex to engage in electron and energy transfer reactions has been conducted. / The solution self-assembly of block copolymers that contain Ru(bpy) 32+ complexes was examined first. Using a series of these block copolymers, a detailed study of the effects of block length, block ratio, polymer concentration and solution conditions on the copolymer self-assembly is presented. Using TEM, a number of morphologies were reproducibly observed including star micelles, large compound micelles, tubules, and interestingly, vesicles. These structures all contain the metal complex Ru(bpy)3 2+ within their core domains. / The luminescence properties of two block copolymers containing Ru(bpy) 32+ were examined: one polymer self-assembled into star micelles, the other into vesicles. Comparison of the unassembled polymer chains and the self-assembled polymers indicated that self-assembly, and confinement of the Ru(bpy)32+ complexes into the core domains of the aggregates, did not seriously adversely affect the luminescence properties of the metal complex. Measurement of the luminescence lifetime decay of the polymers suggested that energy migration occurred among the metal complexes along the polymer chain. The ability of the metal complexes within self-assembled structures to participate in electron transfer reactions with small molecules was also explored. It was found that from within the core domains of self-assembled structures, the Ru(bpy)32+ complexes could still engage in electron transfer reactions with molecules on the outsides or the insides of the aggregates, likely a result of energy migration. / The ability of Ru(bpy)32+ complexes within the cores of micelles to participate in energy transfer was explored. Micelles were formed in aqueous solutions using polymers that possessed both the metal complex and a water-soluble block. Several methods were attempted to encapsulate two molecules, a derivative of coumarin 2 and an Os(bpy)3 2+-based molecule, inside these micelles. It was observed that Ru(bpy) 32+ could act as an energy acceptor from the coumarin derivative, and could act as an energy donor to the osmium-based complex. Encapsulation of the small molecules greatly enhanced the efficiency of energy transfer, by non-covalently bringing the small molecules in close proximity to the Ru(bpy)32+ complexes. / Polymers were synthesized that contained a Ru(bpy)3 2+-based block and were terminated with the molecular recognition unit biotin. These polymers, upon self-assembly, formed micelles with biotin groups on their periphery. The addition of the protein streptavidin, which has a strong binding affinity for biotin, resulted in the aggregation of the self-assembled structures. This established the potential for self-assembled metal-containing aggregates to form higher-order structures. / Early work is presented in Appendix A involving block copolymers that contain hydrogen-bonding groups. Several methods were attempted to elucidate the solution morphologies of these polymers, namely IR, 1H NMR, DLS, and pyrene fluorescence. The transition of this initial work to polymers that contain the Ru(bpy)32+ complex is also described.

Cement-based materials are of importance in the construction of geothermal wells and high-temperature oil and gas wells. These materials fill the annulus between the well casing and the rock forming a protective layer, known as sealant, which is used primarily to secure and support the casing inside the well. In addition it prevents entry of unwanted fluids into the well and communication between formation fluids at different levels. These cement based sealants need to perform for many years at high temperatures and in severe chemical environments; conditions which can cause the material of the well-casing to degrade resulting in reduced strength and increased permeability. The aim of this study is to develop new materials which will have the potential properties (high strength and low permeability) for use as sealants in geothermal and deep, hot oil wells. In order to do this special cement slurries, based on the CaO−Al2O3−SiO2−H2O (CASH) hydroceramic system, have been synthesised over the temperature range 200 to 350 °C (i.e. the typical working temperature of these wells). The additives used in these cement slurries are silica flour and alumina. A detailed description of a suite of novel hydroceramic compositions over the temperature range 200 to 350 °C is given. X-ray diffraction has been used to determine the mineralogical composition and Rietveld refinement to quantify the known phases present at different temperatures. In addition the chemistry of some of the major phases present has been examined using electron probe microanalysis. Scanning electron microprobe and simulation software have been employed to study the crystal shape of these major minerals. The engineering properties of the hydroceramic materials are very important. A study of the compressive strength and permeability has been carried out over a range of temperature (200 to 350 °C). In addition permeability has been calculated using simulation software and the results compared with experimental values. Hydroceramic formulations with excellent strength and permeability measurements have been found. Some of these formulations have been tested for durability under simulated well conditions. These materials have been immersed into different brines for a certain period of time at temperatures between 200 to 300 °C. Some preliminary results regarding the changes in mineralogy in these samples are presented in this thesis. These experiments have been carried out at the Synchrotron Radiation Source (SRS) using tomographic energy-dispersive diffraction imaging (TEDII).

The detailed structure of the myofibrillar material in fibres from different muscles has been studied. Specimens have been obtained from human muscles and from different muscles frequently examined in experimental studies. Both light- and electron microscopical techniques have been used. Of central importance has been the method, which makes it possible to prepare ultrathin sections of frozen tissue, i.e. cryo-ult- ramicrotomy. A number of techniques for image analysis have been applied in order to obtain objektive data from the micrographs. In Paper I the present knowledge about muscle fibre structure, cryo-- sectioning and image analysis is summarized and relevant methodological problems are discussed. Paper II describes the detailed structure of the C-zone of the A-band and shows, above all, that structures occur with different repeats along the long axis of the myofibril. Paper III describes the subcellular organization of different fibres in a homogeneous (based on enzyme histochemical mATPase) population, and shows that different structural characteristies can vary independently of each other. Paper IV describes the structural diversity of the myofibrillar M-band, and paper V the diversity of the myofilament fine structure in different fibres. The results show that there is a most sophisticated, and previosly unrealized, structural specialization both within the myofibrils and between myofibrils from different fibres and muscles, even if the fibres are of the same fibre type. The findings suggest that generally used models, showing the structural organization within myofibrils and myofilaments, are oversimplifications. The fibre population is more heterogeneously built up than the common systems for fibre type classification makes one to belive. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 5 uppsatser.</p> / digitalisering@umu

This thesis work describes the fabrication and surface enhanced Raman spectroscopy (SERS) characterization of vertically aligned nitrogen (N) doped multi walled carbon nanotube (MWCNT) forests coated by silver (Ag) and gold (Au) nanoparticles. In the present work, the CNT forests were grown from a catalyst metal layer by the chemical vapor deposition (CVD) process at temperature of 800 oC and a physical vapor deposition (PVD) and annealing processes were applied subsequently for the evaporation and diffusion of noble metal nanoparticles on the forest. Transistor patterning of 20, 50 and 100 μm were made onto the silicon-oxide (SiO2) wafers through the photolithography process with and without depositing a thickness of 10 nm titanium (Ti) buffer layer on the Si-surfaces. Iron (Fe) and cobalt (Co) were used together to deposite a thickness of 5 nm catalyst layer onto the Single Side Polished (SSP) wafers. As carbon and nitrogen precursor for the CNT growth was used pyridine. Two different treatment times (20 and 60 minutes) in the CVD process determined the CNT forest height. Scanning Electron Microscopy (SEM) imaging was employed to characterize the CNT forest properties and Ag and Au nanoparticle distribution along the CNT walls. The existence of “hot spots” created by the Ag and Au nanoparticles through the surface roughness and plasmonic properties was demonstrated by the SERS measurements. Accordingly, the peak intensity at wave number of 1076 cm-1 was picked up from each SERS spectra to establish the Ag- and Au-trend curves with different concentrations of 4-ATP solution. The SERS mapping was also carried out to study the Ag- and Au-coated CNT surface homogeneity and “hot spots” distribution on the CNT surface. The SERS enhancement factors (EF) were calculated by applying an analyte solution of ethanolic 4-ATP on the CNT surface. The calculated values of EF from Ag- and Au-coated CNT forests were 9×106 and 2.7×105 respectively.

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Multiple sclerosis is a progressive autoimmune disease where myelin is gradually stripped from axons. Axon degeneration inevitably follows protracted myelin loss ultimately leading to irreversible neurological decline. To better understand the cellular mechanisms associated with the axon loss phase of the disease, spinal cord axons from the experimental autoimmune encephalomyelitis (EAE) animal model of multiple sclerosis were examined using correlated in vivo time-lapse microscopy and serial section transmission electron microscopic (ssTEM) reconstruction. A novel technique, termed near infrared burning (NIRB), was developed that took advantage of a femtosecond-pulsed mode locked laser’s ability to create photoconvertable fiducial markers for routine identification of previously imaged axons for ssTEM reconstruction. This combination of imaging techniques revealed the subcellular milieu that underlies axon degeneration at both the light and electron microscopic level. In particular, paranodal regions of axons in EAE animals contained a significantly higher population of mitochondria with large rounded, electron lucid, vesiculated mitochondria with unorganized cristae compared to controls. This effect was largely restricted to the paranodal region and was not always associated with direct immune cell interaction or myelin loss. Together, these results suggest a novel mechanism for axon degeneration that is not only focal in nature, but decoupled with myelin loss in the EAE animal model of multiple sclerosis. / Department of Biology