The Neolithic and late Iron Age pottery from the settlement site of Pool, Sanday, Orkney, was studied on two levels. Firstly, a morphological and technological study was carried out to establish a sequence for the site. Secondly an assessment was made of the usefulness of X-ray Fluorescence Analysis, Inductively Coupled Plasma Spectrometry and Petrological analysis to coarse ware studies, using the Pool assemblage as a case study. Recording of technological and typological attributes allowed three phases of Neolithic pottery to be identified. The earliest phase included sherds of Unstan Ware. This phase was followed by an assemblage characterised by pottery with incised decoration, which was stratified below a traditional Grooved Ware assemblage. The change in pottery styles and manufacturing methods with the Grooved Ware indicated that it evolved elsewhere. Grass tempered and burnished pottery characterised the Iron Age assemblage. Pottery samples from all phases of the site were analysed by XRF and ICPS. In addition, pottery from late Iron Age sites in the area was analysed for comparison with the Pool Iron Age pottery. XRF and ICPS analyses did not distinguish between either different phases at Pool or different Orcadian sites. This was attributed to the similarities in geological deposits over much of Orkney and the variations which can occur within a clay source. A clay survey was carried out in the vicinity of the site, and samples taken for comparison with the Pool pottery. Identification of rocks and minerals in thin section, and grain-size analysis, indicated that the Pool pottery was made locally to the site, and that both primary and secondary clays were used. It was concluded that petrological analysis is more suitable than elemental analysis in the study of coarse wares.

This study was conducted to investigate the urban geochemistry of the city of Windsor (Ontario) and to provide added source apportionment information to work being carried out by the Canadian government. The goal of this study was to investigate the distribution, spatial variation and sources of manganese in urban Windsor soil. The literature indicates that human exposure to high levels of manganese, via inhalation, can cause respiratory and/or neurological effects. At the outset of the present study it was first hypothesized that vehicular traffic was the dominant source of anthropogenic manganese. An alternative hypothesis was that there were multiple anthropogenic sources of manganese in Windsor. The sample collection scheme was designed to determine (1) the current and background soil concentrations of manganese in Windsor, (2) the spatial distribution of manganese in order to reveal sources of manganese, and (3) the manganese content of moss-sequestered airborne particles, which can potentially deposit onto the soil surface, using low-technology biomonitoring. The first phase of the study consisted of a preliminary soil survey which identified elevated areas of soil manganese concentrations. During this survey, the field efficiency of a field portable X-ray fluorescence (FPXRF) instrument, as well as sample preparation methods were evaluated. Efficiency of the FPXRF was determined by comparison to ICP-MS, a traditional trace element analysis method. The preliminary soil survey identified several areas of elevated (ranging from 884 to 2390 ppm) soil manganese which were further investigated during the second, more complete, soil survey. The moss biomonitoring technique of using moss bags was used to collect airborne particles for semi-quantitative analysis. Analysis of soil samples included total manganese and other trace elements, pH, moisture and carbon content, and manganese speciation. Urban Windsor soil manganese distribution revealed both natural and anthropogenic sources of soil manganese and three distinct soil sample types, transect, baseline and natural. In general, manganese in Windsor had a west-to-east trend of decreasing levels in soil and moss-sequestered airborne particles. The latter showed a modern-day elemental signature while the former (collocated soil) a legacy elemental signature. It was concluded that both the FPXRF instrument and the moss biomonitoring technique can be useful screening tools in studies of urban environments.

The objective of this thesis is to categorize carpet types according to their XRF spectra and verify if further classification of carpets is possible for use of an XRF analysis system in the carpet manufacturing line. This thesis consists of (1) implementing and studying effective algorithms for automated analysis of X-ray spectra, (2) comparing known algorithms for X-ray spectra analysis, and (3) implementing our own algorithm for classification of carpets spectra obtained for further fluorine online analysis of XRF inspected carpets. This research is intended for quick and accurate automated analysis of raw XRF spectra and matching analysis results to a database of XRF spectra of raw carpets. The research uses spectrum signal processing and spectrum analysis regarding efficacy of combined methods for XRF inspected carpets. X-Ray Fluorescence is a key technology for detection of chemical elements. Fluorine is a key element for carpet's quality. XRF has been chosen to be a potential candidate to measure fluorine since it is a versatile tool for low concentration element detection. Due to specific XRF background spectrum for each different carpet type, carpet samples may need specific calibrations for further computation of carpet fluorine concentration. Automating the detection of the carpet type is intended to help in automating the XRF calibration.

The ability to quickly and accurately quantify the plutonium (Pu) content in pressurized water reactor (PWR) spent nuclear fuel (SNF) is critical for nuclear forensics purposes. One non-destructive assay (NDA) technique being investigated to detect bulk Pu in SNF is measuring the self-induced x-ray fluorescence (XRF). Previous XRF measurements of Three Mile Island (TMI) PWR SNF taken in July 2008 and January 2009 at Oak Ridge National Laboratory (ORNL) successfully illustrated the ability to detect the 103.7 keV x ray from Pu using a planar high-purity germanium (HPGe) detector. This allows for a direct measurement of Pu in SNF. Additional gamma ray and XRF measurements were performed on TMI SNF at ORNL in October 2011 to measure the signal-to-noise ratio for the 103.7 keV peak. Previous work had shown that the Pu/U peak ratio was directly proportional to the Pu/U content and increased linearly with burnup. However, the underlying Compton background significantly reduced the signal-to-noise ratio for the x-ray peaks of interest thereby requiring a prolonged count time. Comprehensive SNF simulations by Stafford et al showed the contributions to the Compton continuum were due to high-energy gamma rays scattering in the fuel, shipping tube, cladding, collimator and detector1. The background radiation was primarily due to the incoherent scattering of the 137Cs 661.7 keV gamma. In this work methods to reduce the Compton background and thereby increase the signal-to-noise ratio were investigated. To reduce the debilitating effects of the Compton background, a crystal x-ray spectrometer system was designed. This wavelength-dispersive spectroscopy technique isolated the Pu and U x rays according to Bragg's law by x-ray diffraction through a crystal structure. The higher energy background radiation was blocked from reaching the detector using a customized collimator and shielding system. A flat quartz-crystal x-ray spectrometer system was designed specifically to fit the constraints and requirements of detecting XRF from SNF. Simulations were performed to design and optimize the collimator design and to quantify the improved signal-to-noise ratio of the Pu and U x-ray peaks. The proposed crystal spectrometer system successfully diffracted the photon energies of interest while blocking the high-energy radiation from reaching the detector and contributing to background counts. The spectrometer system provided a higher signal-to-noise ratio and lower percent error for the XRF peaks of interest from Pu and U. Using the flat quartz-crystal x-ray spectrometer and customized collimation system, the Monte Carlo N-Particle (MCNP) simulations showed the 103.7 keV Pu x-ray peak signal-to-noise ratio improved by a factor of 13 and decreased the percent error by a factor of 3.3.

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Metal ions play essential roles in biological functions including catalysis, protein stability, DNA-protein interactions and cell signaling. It is estimated that 30% of proteins utilize metals in some fashion. Additionally, methods by which metal ions can be visualized have been utilized to study metal concentrations and localizations in relation to disease. Understanding the roles metals play in biological systems has great potential in medicine and technology. Chapters 1 and 2 of this dissertation analyzes the structure and function of the Mn-dependent enzyme oxalate decarboxylase (OxDc) and Chapter 2 presents a bioinformatic analysis of the cupin superfamily that provides the structural scaffold of the decarboxylase. The X-ray crystal structure of the W132F variant was determined and utilized together with EPR data to develop a computational approach to determining EPR spectra of the enzyme’s two metal-binding centers. Furthermore, a variant in which the catalytic Glu162 was deleted revealed the binding mode of oxalate, the first substrate-bound structure of OxDc. OxDc is a member of the cupin superfamily, which comprises a wide variety of proteins and enzymes with great sequence and functional diversity. A bioinformatics analysis of the superfamily was performed to analyze how sequence variation determines function and metal utilization. Chapters 3 and 4 discuss the expansion of lanthanide-binding tags (LBTs) to in cellulo studies. Lanthanide-binding tags are short sequences of amino acids that have high affinity and selectivity for lanthanide ions. An EGF-LBT construct used to quantify EGF receptors on the surface of A431 and HeLa cells. The results from the LBT quantification are consistent with previous studies of EGFR receptors in these cell types, validating the use of this method for future studies. The potential of using LBTs for X-ray fluorescence microscopy (XFM) was also investigated. LBT-labeled constructs were utilized to investigate if membrane bound as well as cytosolic LBT-containing proteins could be visualized and localized to their cell compartments via XFM; both membrane-localized and cytosolic proteins were successfully visualized. With the high resolution (< 150 Å) obtainable with new synchrotron beamline configurations LBTs could be used to study nanoscale biological structures in their near-native state.

A new multi-purpose surface analytical instrument (the Hallam instrument) is described, which combines the surface specific information obtained using x-ray photoelectron spectroscopy (XPS), with bulk information obtained using Energy Dispersive X-ray (EDX) detection. A 15kV electron gun and an ultra high vacuum EDX detector give the instrument an EDX mapping capability. To exploit this to its full potential, spatial alignment of EDX maps acquired at various electron beam energies, E[o], was required. The misalignment of images acquired at various E[o] values was investigated, and a means of describing the misalignment as a function of E[o] was presented. An algorithm was developed which would allow the alignment of offline images acquired at different E[o] values. This was demonstrated on images acquired on both the Hallam instrument and on a Phillips XL40 electron microscope. The small area XPS system developed by Kratos analytical gave a spatial resolution of 30pm at the centre of the field of view, although this deteriorated away from the centre. The reasons for this deterioration in spatial resolution were investigated, and two methods of improving the system were presented. The improvements were implemented on the Hallam instrument and demonstrated using a standard silver grid sample. The small area XPS was applied to a TiAINi coated stainless steel sample to demonstrate its application to real samples, and to display the spatial alignment between the XPS and EDX maps. Finally, the instrument was calibrated for quantitative XPS studies. This involves determining the response of the instrument as a function of the photoelectron kinetic energy. From several methods presented in the literature, the most appropriate was chosen for calibration of the 'Hallam' instrument. The effectiveness of the method used was assessed by recording spectrum intensity from pure elemental standards, and comparing the results with intensity values calculated using the calibration curves.

abstract: Neurotoxicology has historically focused on substances that directly damage nervous tissue. Behavioral assays that test sensory, cognitive, or motor function are used to identify neurotoxins. But, the outcomes of behavioral assays may also be influenced by the physiological status of non-neural organs. Therefore, toxin induced damage to non- neural organs may contribute to behavioral modifications. Heavy metals and metalloids are persistent environmental pollutants and induce neurological deficits in multiple organisms. However, in the honey bee, an important insect pollinator, little is known about the sublethal effects of heavy metal and metalloid toxicity though they are exposed to these toxins chronically in some environments. In this thesis I investigate the sublethal effects of copper, cadmium, lead, and selenium on honey bee behavior and identify potential mechanisms mediating the behavioral modifications. I explore the honey bees’ ability to detect these toxins, their sensory perception of sucrose following toxin exposure, and the effects of toxin ingestion on performance during learning and memory tasks. The effects depend on the specific metal. Honey bees detect and reject copper containing solutions, but readily consume those contaminated with cadmium and lead. And, exposure to lead may alter the sensory perception of sucrose. I also demonstrate that acute selenium exposure impairs learning and long-term memory formation or recall. Localizing selenium accumulation following chronic exposure reveals that damage to non-neural organs and peripheral sensory structures is more likely than direct neurotoxicity. Probable mechanisms include gut microbiome alterations, gut lining damage, immune system activation, impaired protein function, or aberrant DNA methylation. In the case of DNA methylation, I demonstrate that inhibiting DNA methylation dynamics can impair long-term memory formation, while the nurse-to- forager transition is not altered. These experiments could serve as the bases for and reference groups of studies testing the effects of metal or metalloid toxicity on DNA methylation. Each potential mechanism provides an avenue for investigating how neural function is influenced by the physiological status of non-neural organs. And from an ecological perspective, my results highlight the need for environmental policy to consider sublethal effects in determining safe environmental toxin loads for honey bees and other insect pollinators. / Dissertation/Thesis / Doctoral Dissertation Neuroscience 2016

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Made available in DSpace on 2014-10-09T12:26:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:21Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP