Surface plasmon resonances at the nanoscale hold great potential for applications in many areas, and the characterization of plasmonic nanostructures plays a critical role in the realization of these applications. Electron energy loss spectroscopy (EELS) has emerged as a powerful characterization tool to study the response of plasmonic nanostructures due to its high spatial-resolution and the capability to probe bright as well as dark plasmonic modes. The main limiting factor of EELS is the energy resolution. However, in this thesis, we overcome this limitation using a combination of electron monochromation and the use of the Richardson-Lucy algorithm. We show that the algorithm could be used to obtain effective energy resolutions up to 10 meV. Using EELS we analyze the resonances of planar nanostructures, and we found that the supported resonances can be described as edge and cavity or film modes, behaving as 1D and 2D modes respectively. We also demonstrate that edge modes are unaffected by the presence of bends up to the critical angle of 90◦ where the modes start self-interacting producing large energy shifts. The interaction of plasmon resonances is also studied, and we show that the coupling can be reduced to three behaviors: coupling through the edge, coupling through a corner, and non-coupling. We propose a method to control the coupling through the edge in offset nanowires, by tuning the nodal alignment and spectral overlap of the edge modes. Finally, we analyze the plasmon modes supported by Koch snowflake fractal antennas, and we demonstrate that modes present in the fractals are formed by the edge modes supported by their characteristic edges. This thesis provides a complete picture of the surface plasmon resonances supported by planar nanostructures and demonstrates the ability of EELS to probe and image a wide variety of plasmonic resonances. / Thesis / Doctor of Philosophy (PhD)

The purpose of this study was to examine changes in muscle ultrastructure and strength performance following a single bout of elbow flexor resistance exercise. Eight untrained males performed 8 sets of 8 repetitions at 80% concentric 1 RM. One arm performed only the concentric (CON) phase of the movement while the other performed only the eccentric (ECC) phase. Maximum isometric (MVC), low (LV} and high velocity (HV} concentric peak torque, and evoked contractile property measurements of the elbow flexors were made before and after the bout, and at 24, 48, 72 and 96 h. Needle biopsies were obtained from the biceps brachii prior to the exercise, immediately post-exercise from each arm (POSTCON, POST-ECC}, and 48 h post-exercise from each arm (48H-CON, 48H-ECC). Electron microscopy was used to quantify the extent of fiber disruption in each sample. The severity of disruption was classified as focal (FOC}, moderate (MOD}, or extreme (EXT}. All strength measurements decreased (P s; o. 05} below pre-exercise values immediately post-ex in both arms, but dramatic differences were observed between arms during the subsequent recovery period. MVC, LV, HV and peak twitch torque (PTT) recovered to pre-ex values by 24 h in the CON arm. In the ECC arm, HV did not recover for at least 72 h, and MVC, LV and PTT remained depressed at 96 h. ANOVA revealed a greater (P s; 0.05) number fibers were disrupted in the POST-CON, POST-ECC, 48H-CON and 48H-ECC samples compared to BASE. Significantly more fibers appeared disrupted in the POST-ECC (82%) and 48H-ECC (80%) samples compared to the POSTCON (33%) and 48H-CON (37%) samples, respectively. In addition, the POST-ECC (41%) and 48H-ECC (50%) samples contained a greater number of fibers with EXT disruption compared to the POST-CON (13%) and 48H-CON (17%) samples. Decreases in MVC at 48 h correlated (P ~ 0.05) with the extent of EXT disruption in the 48H-CON and 48H-ECC samples. These data indicate that both the CON and ECC phase of weightlifting produce myofibrillar disruption, with the greatest disruption occurring during the ECC phase. This study was supported by the Natural Sciences and Engineering Research Council of Canada. / Thesis / Master of Science (MSc)

Thesis / Master of Science (MS)

Schwertmannite, a ferric oxyhydroxysulfate mineral typically found under acidic, high sulfate and iron aqueous conditions, such as acid mine drainage environments, was studied using analytical high resolution transmission electron microscopy (HRTEM). HRTEM offers advantages over bulk techniques such as powder x-ray diffraction and pair distribution function (PDF) analysis of synchrotron data, in its ability to discern multiple phases within poorly crystalline nanominerals. Based on extensive HRTEM observations of both natural and synthetic schwertmannite samples, the authors suggest that schwertmannite should not be described as a single phase mineral with a repeating unit cell, but as a polyphasic nanomineral with crystalline areas spanning less than a few nanometers within an amorphous matrix. The few visible lattice fringes observable in both natural and synthetic schwertmannite agree well with d-spacings of goethite (and jarosite in natural samples) implying that the transformation from schwertmannite to these phases occurs as a gradual structural reordering at the nanoscale. In the synthetic study, the complete transformation from schwertmannite to goethite nanorods and nanoparticles within 24 hours at 75°C was observed, indicating a low energetic barrier to schwertmannite's phase transformation. We also found that amorphous silica can be intimately entrained within natural schwertmannite, and that high concentrations of arsenic can be held in close association of nanocrystalline regions of the mineral. / Ph. D.

The major experimental problems involved in this investigation were two in number. The first problem was that of obtaining an accurate calibration of the electron microscope to be used for making electron micrographs. This was done by comparison with a secondary standard. A Bausch and Lomb Type ILS metalloscope, which was calibrated by use of a steel grating furnished by the manufacturer, was used as the secondary standard. The second problem was the examination of yellow iron oxide pigments manufactured by three major manufacturers for the purpose of comparing individual pigment particles and also determining particle shape and dimensions. Both problems were successfully solved and the following observations were made: 1. The magnification of the RCA Type ENC electron microscope used in the investigation is 4274. 2. The particle size and structure of yellow iron oxide paint pigments made by different manufacturers are the same, i.e., 0.5 micron by 0.1 micron and rod-like in structure. / Master of Science

Yes / Previous research on the Iron Age in Britain has argued that no fishing occurred during this period in Britain. This argument has now been complicated by large assemblages of fish bones that have been excavated from Iron Age sites in the Northern Isles. Further investigation into this issue became the focus of the author's MSc dissertation research in 2016, specifically on the recently excavated fish bone assemblages from the site of Swandro on Rousay, Orkney. Analytical methods, including stable isotope analysis and scanning electron microscopy, were applied in an attempt to determine how the fish may have been utilised at the site. Results have revealed evidence that could be interpreted as fishing activity and possible consumption by humans at Swandro. This paper disseminates and further examines these results and considers how this particular project is useful as a pilot study in the application of analytical methodologies to problematic faunal remains such as fish, and why this could be important to future zooarchaeological and environmental archaeological research.

No description available.

No description available.

<p dir="ltr">Viruses are obligate, intracellular pathogens meaning they are dependent on a host to produce progeny virus. Generally, viruses contain genetic material that is encapsulated in a protein shell. This protein shell can be encased in a lipid layer with glycoproteins classifying them as enveloped viruses. Flaviviruses are enveloped, positive sense RNA viruses transmitted through the bites of infected arthropods. Flaviviruses cause a variety of symptoms including general malaise, encephalitis, meningitis, hemorrhagic fever, congenital defects, and death. Approximately 3 billion people are at risk of contracting a flavivirus infection each year and with limited vaccine options, the development of effective therapeutics is critical for global human health. This thesis focuses on characterizing the effects flavivirus membrane perturbation has on structure and infectivity. The rationale behind this work was to determine if the viral membrane can be leveraged as a target for viral inactivation and vaccine development.</p><p dir="ltr">Flavivirus structural studies have identified targets for the development of antivirals and vaccines as well as bottlenecks hindering successful therapeutic development. Chapter 1 situates and expands on the global burden, life cycle, and structure of flaviviruses. Additional information on vaccine availability and how flavivirus structure and antibodies guide vaccine development is provided with emphasis on the importance of understanding flavivirus structural dynamics for successful vaccines.</p><p dir="ltr">Chapter 2 introduces the thesis’s study, where the flavivirus lipid membrane was leveraged as an inactivation target for the development of new vaccine methodology. After learning that Tween 20, a non-ionic detergent, was capable of flavivirus inactivation, a combination of imaging and molecular tools were utilized to characterize the particles after Tween 20 treatment. Increasing temperatures to 37°C improved viral inactivation determined by plaque assay. After determining what concentrations of Tween 20 impaired infectivity, Kunjin Virus (KUNV) was used as a model virus to assess structural changes that occurred during Tween 20 incubation. Resulting particles lacked homogeneity in the size and morphology of the glycoprotein shell but consistently had a reduction of internal structural protein Capsid and similar quantity of viral RNA. Repeated study trails with the French Polynesian strain of Zika Virus (ZIKV) yielded similar results.</p><p dir="ltr">Further experimentation detailed in Chapter 3 describes attempts to expand current knowledge of flavivirus uncoating and assembly mechanisms by disrupting flavivirus structure and protein-RNA interactions. To expand on the results discussed in chapter 2, Tween 20 was used to test disruption of Capsid-RNA binding reactions in vitro as well as induce genome leakage. It was determined that Tween 20 was not directly interfering with the retention of RNA and loss of Capsid, but more likely a result from Tween 20 integrating into the viral membrane. Additionally, after Tween 20 treatments, the RNA remaining was exposed, so ribonuclease protection assays were utilized to see if there was a region of genome that was consistently protected after treatment. The incubation of KUNV with Tween 20 and ribonucleases XRN1, Exo T, and RNase A determined that there was not a genome region consistently protected. Chapter 3 also includes preliminary results of an intra-lab collaboration to develop styrene maleic lipid nanoparticles from purified KUNV as a tool to probe for glycoprotein-Capsid protein interactions.</p><p dir="ltr">In Chapter 4, further analysis of flavivirus asymmetric reconstructions were done with the ZIKV Dakar strain. Previously, flaviviruses have been observed to have imperfect glycoprotein shells which could expose the presumably completely covered lipid membrane. To further evaluate asymmetric features, purified ZIKV was incubated with antigen binding fragments (Fabs) to stabilize the virions for improved resolution. Mature ZIKV was incubated with potently neutralizing Fab ZV-117 and immature ZIKV with ZV-67. In the mature and immature asymmetric reconstructions, a disruption in the glycoprotein shell was observed suggesting that the viral membrane is exposed.</p><p><br></p>

Particle contamination control is a critical issue for the semiconductor industry. In the near future, this industry will be concerned with the chemical identities of contaminant particles as small as 0.01 pm in size. Therefore, analytical techniques with both high chemical sensitivity and spatial resolution are required. Transmission electron microscopy (TEM) provides excellent spatial resolution and yields structural and compositional information. It is rarely used, however, due to the difficulty of sample preparation. The goals of this research are to promote the use of TEM as an ultrafine particle analysis tool by developing new sample preparation methods, and to exploit the new TEM techniques for analysis of particles in semiconductor processing fluids. A TEM methodology for the analysis of particulate contaminants in fluids with an elemental detectability limit as low as 0.1 part per trillion (ppt), and a particle concentration detectability limit as low as 1 particle/ml for particles greater than 0.2 pm was developed and successfully applied to the analysis of particles in HF, H202, de-ionized (DI) water, and on the surface of an electronic device. HF samples from three manufacturers were examined. For HF (B), the maximum particle concentration was 8.3 x 103 particles/ml. Both a viscous material and lath-shaped particles were observed. The Sb concentration was less than 0.6 part per billion (ppb). HF (C) was the cleanest. CaF2 and TiO2 particles were identified in HF (D). For H2 02, iron and tin oxides and hydroxides were identified. The maximum particle concentration was 990 particles/ml. The Sn and Fe concentrations were less than 0.3 ppb. Spherical and dendritic particles were observed. For DI water, spherical and dendritic particles (<2 particles/ml), and particles containing Fe or Si with concentrations less than 0.1 ppt were observed. Contaminants on an electronic device surface were also analyzed. Clusters of small particles were determined to be a mixture of aluminum oxides and aluminum silicates.