Heavy metal pollution from a smelter in Trail, British Columbia may be a source of anthropogenic Pb contamination in northeastern Washington lakes. This smelter, located near the Canadian border, has been operating since 1895. It dumps slag – waste created during smelting – into the Columbia River, and emits metals into the atmosphere. We analyzed sediment samples from lakes in northeastern Washington to determine the source of anthropogenic Pb. Determining whether smelter Pb travels via airways and contaminates the environment is a critical health issue. We measured Pb isotope ratios of lake sediments on a multiple-collector inductively coupled plasma mass spectrometer, following acid dissolution of the samples and separation of the Pb. Lead isotope ratios provide a tool to trace anthropogenic Pb. Pb206, Pb207, and Pb208 are daughter products of U238, U235, and Th232, respectively. Pb204 is not produced by radioactive decay. Each parent isotope has a different half-life, so different geological sources have different relative amounts of each Pb isotope. This gives every Pb source its own Pb isotope fingerprint. No natural processes alter the fingerprint of a Pb source after industrial processing. Therefore, we can test for smelter emissions in lake sediments. Lake sediments contain natural and anthropogenic Pb. In Pb207/204 vs. Pb206/204 space, Pb from slag samples has relatively low values, with Pb206/204 ratios from 16.7-17.4. Natural Cascade Pb has much higher isotopic ratios with Pb206/204 ratios of 18.5-19.0. Lake sediment Pb covers most of this range, with Pb206/204 ratios from 17.02-18.32. All analyzed samples contain significant anthropogenic Pb. Lakes closer to the smelter generally show higher contributions of anthropogenic Pb concentrations. Additionally, the gradation in anthropogenic Pb contamination forms a pattern expected from prevailing winds transporting smelter emissions. The Pb isotope data provide strong evidence for airborne Pb contamination of some Washington lakes from the Trail, British Columbia smelter.

 Passage of Eocene slab windows beneath the Pacific Northwest is documented by plate motion reconstructions as well as the on-land geologic record. The earliest known record of this process is the 55-44 Ma Basalt of Summit Creek (BSC), a steeply dipping 1600 m section of subaerial lavas exposed southeast of Mount Rainier. These tholeiitic basalts erupted in an arc setting (as evidenced by underlying tuffs) but display a mix of MORB and OIB traits and have isotopic signatures of a depleted mantle source. In chemical and isotopic composition BSC lavas overlap with the voluminous Crescent Formation basalts on the Olympic Peninsula, which are of similar age but located ~100 km farther west. A few BSC samples display arc traits (e.g., HFSE depletions); we suggest these may record interaction between ascending asthenospheric mantle / melts and a mantle wedge previously modified by subduction processes. Compositional diversity among BSC lavas appears to reflect both fractional crystallization and source heterogeneity. Modeling with MELTS (Ghiroso and Sack, 1995) indicates that differentiation dominated by removal of clinopyroxene and plagioclase took place at mid crustal depths (P = 5 kbar) and that the parent magma had <0.2 wt. % water. However, this process cannot account for all incompatible element data, which appear to require multiple parent magmas. The Eocene was a critical juncture in Pacific Northwest tectonics. Subduction, slab window magmatisim, terrane accretion and mantle plume activity were all ongoing at this time. Increased understanding of the petrology BSC will contribute to our overall knowledge of the evolution of the western margin of North America.

This project seeks to better understand climate change corollary to the migration of the Intertropical Convergence Zone (ITCZ) in the tropical Pacific from the Little Ice Age (~AD 1400-1850) to the present using hydrogen isotopes as a proxy for climate change. During this time, the ITCZ is hypothesized to have reached its most southern location, the consequences of which were evident on a global scale. However, more research is needed to further investigate this hypothesis. Specifically, this study examines hydrogen isotope ratios of the source specific lipids Taraxerol and Dinosterol from Lake Escondido, Isabela Island, Galapagos. Lipids were solvent-extracted from sections of the cores, separated through silica gel columns, and the ratio of Deuterium and Hydrogen (δD) of specific lipids was quantified using a Gas Chromatograph-Isotope Ratio Mass Spectrometer. The combined fluxes of both terrestrially and aquatically sourced δD ratios over time provide a proxy for climate change through the present. Due to the widespread effects of the ITCZ on global hydrology, understanding its movement, and what triggers migration, can provide insight into future climate scenarios.

Genome-Wide Association Studies (GWAS) determine the places in the genome where there are differences, Single Nucleotide Polymorphisms or SNPs, in genetic sequences of individuals who have a disease as compared to a control group. I used the Human Genome Epidemiology (HuGE) Navigator to analyze the literature on GWAS related to autoimmune disorders.  I then performed a meta-analysis on published literature that had combined multiple GWAS with previously published findings on candidate genes for multiple autoimmune diseases and that had also established shared risk genes. The meta-analysis assisted in extracting not only the statistical methods most often employed, but also biostatistical software used in their analyses.  Using these studies as models, I took sets of autoimmune disorder GWAS and combined that information with previously proposed candidate genes for which studies were lacking.  I statistically and systematically explored possible shared genetic locations to discover any novel and significant associations.  I expect that such a systematic review of existing studies will highlight as yet unseen patterns of shared risk genes when data from two or more autoimmune GWAS studies are compared to previously proposed candidate genes.  The ability to identify shared risk genes is increased by combining data obtained from GWAS of autoimmune diseases.  Although clinically distinct, autoimmune diseases may share common disease pathogenesis mechanisms that may be implicated only by using analysis of genetic factors between diseases.  By further elucidating shared genetic risk factors, this knowledge will contribute to our understanding of genetic epidemiology and will help to define and characterize environmental interventions with the potential to prevent the development of autoimmune diseases.

Barrett’s Esophagus (BE) is an inflammation of the lower esophagus. This inflammation can progress to cancer through a stage called High Grade Dysplasia (HGD). One approach to early detection of HGD is the use of light emitting “beacons “consisting of fluorescently labeled peptides targeted to HGD tissue biomarkers. Our laser based Scanning Fiber Endoscope (SFE) possesses the ability to capture live images of the esophagus during examinations and also excite and locate fluorescently tagged targets. Refining SFE fluorescence imaging for clinical use requires mathematical algorithms such as image stitching and distance compensation. Image stitching combines a series of partial views of a 3-D surface into a composite view of the entire surface. Distance compensation addresses the issue of fluorescence signal reduction as the distance between the light emitting beacon and endoscope increases. Phantoms are synthetic mimics of disease conditions used to refine and calibrate new medical devices. This research was directed toward the development of a low-cost, flexible, and durable esophagus phantom with color matching to provide a realistic model of BE. The color of inflamed BE tissue and healthy tissue were matched using quantitative combinations of commercial acrylic paints to create recipes for both tissue types. The resulting paint mixtures were applied to the interior of a latex cast cylinder mimicking the dimensions of an adult esophagus. The painted latex models were shown to a panel of gastroenterologists for approval. The end result was the development of a color realistic phantom onto which fluorescent targets could be affixed. The phantom was imaged using the SFE and demonstrates 2D stitching with distance compensation. (C. Yang, V. Hou, L. Nelson, E. Seibel. J. Biomed. Optics, Feb 2013) Future work extends similar techniques to develop brain tissue phantoms for the calibration of the SFE after integration onto the RAVEN surgical robot.