Physical Sciences and Mathematics Commons^™

The Atomic And Electronic Structure And Tunability Of Ruddlesden-Popper Phases For Photovoltaic Applications, Britt A. Tyler

WWU Graduate School Collection

There is an increasing need for alternative energy sources that reduce the global reliance on fossil fuels. Since their demonstration in 2009, perovskite solar cells (based on compounds with the formula ABX₃, such as CH₃NH₃PbI₃) have become an extremely promising and active research area. Still, there are obstacles to the widespread use of these technologies, including their instability and the environmental impacts of lead. It is therefore important to find ways to modify and tune the structure and properties of perovskites to optimize their stability and photovoltaic performance. This research explores a …

Surface Modified Gold Nanorods Based Mercury Sensor, Tianqi Luan

WWU Graduate School Collection

The high toxicity of mercury in the form of inorganic vapor and organic compounds has become a major concern leading scientists to investigate more accurate and effective methods for the quantification of residue mercury in drinking water, aquaculture products and industrial wastes. In this research, we designed a mercury sensor based on the amalgamation between mercury and gold nanorods (AuNRs) which relate the longitudinal surface plasmon resonance (LSPR) peak shift induced by aspect ratio (AR) change after amalgamation. However, most of AuNRs synthesized based on seed mediated methods use either citrate or hexadecyl trimethyl ammonium bromide (CTAB) as surface stabilizing …

Synthesis Of A Stimulus Responsive Phosphine Ligand And Metal Binding Studies, Gabriel Bourne

WWU Graduate School Collection

Cations have been shown to modify a variety of properties of transition metals, including bite angle, isomerization, substrate control, and catalytic activation. Herein describes the synthesis of a novel stimulus responsive phosphine ligand. Ligand binding studies by NMR salt titration show a preference in the order of Na⁺ > Li⁺ > K⁺. Platinum dimethyl and dichloride complexes with the phosphine ligand were also synthesized. Isomerization of the platinum chloride complex between cis and trans is reported.

Impacts Of Major Freshwater Ions On The Acute Toxicity And Chemical Behavior Of Silver Nanoparticles, Claire A. Walli

WWU Graduate School Collection

Silver nanoparticles (AgNPs) are increasing in presence in commercial and medical products due to their bactericidal properties and can be transported into the environment during the laundering, use, and waste of those products. Strong evidence suggests aqueous silver (Ag⁺) dissolved from the AgNP surface is the toxic component of AgNPs but there is no consensus on the possibility of additional nanoparticle-specific properties that elicit toxicity. Ag⁺ toxicity to freshwater organisms has been well studied using the Biotic Ligand Model (BLM), which describes how water quality conditions, such as the concentrations of certain freshwater ions, affect the toxicity …

Seismic Structure Of Tanaga Island, Alaska, Kevin F. (Kevin Francis) Lally

WWU Graduate School Collection

Tanaga Island is located in the Central Aleutian Islands and includes four stratovolcanoes: Sajaka, Tanaga, and East Tanaga in the northwest, and Takawangha in the central part of the island. Of these volcanoes, only Tanaga has a record of historical eruptive activity (in 1914). Over 3,000 earthquakes have been recorded beneath the island and the surrounding offshore region since the six-station seismic network was emplaced in 2003. The origin of these earthquakes is not completely understood, and to arrive at this understanding, more accurate hypocenter locations and power spectra need to be determined. A better analyses including improved locations of …

Progress Towards The Substrate-Bound Structure Of Streptococcus Pneumoniae Sortase A, Nicholas M. Horvath

WWU Graduate School Collection

Sortases are cysteine transpeptidases found primarily on the cell surface of Gram-positive bacteria. Sortase-mediated ligations have become an attractive option for protein modification chemistry, enabling the synthesis of a wide range of non-natural polypeptide derivatives. Attempts at understanding how these enzymes recognize and bind substrates are integral to furthering their usefulness in protein engineering and, potentially, treatment of bacterial diseases. However, the variable substrate specificity and activity between homologs of these enzymes is not yet fully understood. Of specific interest to us is sortase A from Streptococcus pneumoniae (SrtA_pneu), as it demonstrates a broad substrate tolerance not …

Validation Of Predicted Tsunami Inundation For The Inland Coast Of The Salish Sea Associated With Cascadia Subduction Zone Earthquakes, Paige Morkner

WWU Graduate School Collection

The Cascadia subduction zone is understood to produce large, Mw 9.0, earthquakes every 300-1000 years. As a result of large ruptures along the fault, Washington, Oregon and Northern California, are susceptible large tsunamis along the coast. Hazard modeling and mapping along the Cascadia subduction zone has concluded that large tsunamis are able to travel through the Strait of Juan de Fuca and inundate coastal regions of the Salish Sea and Puget Sound. However, to improve modeling efforts, field validation of models is required. Tsunamis can move material from the near shore and beach and deposit in low-laying coastal marshes and …

Clinopyroxene Trace Element Chemistry As A Proxy For Magma Compositional Variations In The Izu Bonin Rear Arc Over The Last 15 Million Years, Kimberly N. (Kimberly Nicole) Wurth

WWU Graduate School Collection

This study presents major and trace element chemistry of clinopyroxene (CPX) in 0-15 Ma core material recovered from Site U1437 during IODP Expedition 350. Because no fresh glass is present in the core samples older than 4.4 Ma, and hence there is no way to directly determine magma compositions, my study presents the development of a novel method for calculating liquid compositions from CPX grains in volcaniclastic sediments using distribution coefficients and trace elements measured in CPX.

Geochemical data from CPX grains was acquired using a laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS). These data were used to calculate trace element …

Under What Conditions Could Eelgrass Measurably Drawdown Carbon? Relating Carbon Drawdown To Pco2, Irradiance, And Leaf Area Index Of Zostera Marina, Tyler Tran

WWU Graduate School Collection

Seagrass meadows, common to coastal habitats, have been identified as potential short-term refugia for calcifying organisms from ocean acidification (OA). In nearshore, soft-sediment habitats of the Salish Sea, eelgrass (Zostera marina L.) is the dominant seagrass species, and several studies have found that eelgrass is effective at taking up inorganic carbon and may be carbon-limited, potentially increasing uptake potential in the future. However, irradiance levels vary throughout a day and can therefore influence rates of carbon uptake and release through the relative rates of photosynthesis and respiration. Eelgrass meadows vary in terms of meadow size, shoot density and morphology, …

Development Of A Rangeland Degradation Risk Model For The Peruvian Andes, Colin Schmidt

WWU Graduate School Collection

This study developed a Rangeland Degradation Risk Model for the Peruvian Andes based on the Unit Stream Powered Erosion Deposition Model using globally available datasets. A supervised land cover classification was conducted to identify suitable grazing areas and to conduct a regional analysis of susceptibility to erosion. Field data were collected from two different study sites, Huascaran National Park and Nor Yauyos Cochas Landscape Reserve, and were used to assess the model’s accuracy in different ecosystems and land use types. Field data were also leveraged to identify additional data needs and other potential drivers of degradation not taken into account …

Isopeptide Ligations Catalyzed By Streptococcus Suis Sortase A, Sarah Bowersox

WWU Graduate School Collection

Chemically modified proteins are critical components of modern therapeutics and basic research. To generate non-natural protein derivatives, bacterial sortase enzymes have been effective due to their ability to catalyze selective ligations between protein targets and functional groups that are uncommon in nature. Thus far, the enzymatic approach using sortase has been limited to modifications at the termini of peptide chains. Here we describe efforts to develop a sortase-mediated strategy for the formation of isopeptide bonds at the side chains of internal lysine residues. To this end, we have identified a sortase A homolog from Streptococcus suis (SrtA_suis) that …

A Multivariate Analysis Of The Relationship Between The Water Quality Conditions And Algal Species Composition Of Six Mountain Lakes In The North Cascades, Wa, Usa, Michael P. Lawlor

WWU Graduate School Collection

The objective of my study was to characterize the water quality conditions and algal species composition of six mountain lakes in the North Cascades of Washington, USA. Exploratory data analysis examined water quality conditions and algal species composition separately, then determined if they were related. The lakes exhibited median temperatures from 13.3 °C to 20.8 °C, had nitrate and soluble reactive phosphate concentrations below 100 µg/L and 6 µg/L, respectively, were slightly acidic (pH 5.1-6.9), and had median dissolved oxygen concentrations ranging from 6.7 mg/L to 10.6 mg/L. Over 340 non-diatom algal taxa were identified. Algal species richness was positively …

Modeling The Effects Of Climate Variability On Hydrology And Stream Temperatures In The North Fork Of The Stillaguamish River, Kyra Freeman

WWU Graduate School Collection

The Stillaguamish River in northwest Washington State, USA, provides water resources to local agriculture, industry and First Nations Tribes, and provides crucial habitat for several endangered species of salmonids. The watershed experiences a mild maritime climate and high relief, with rain and snowmelt dominating the streamflow. In anticipation of shifts in snowpack, streamflow, and stream temperature, I use projected global climate scenarios and numerical models to examine future climatic variability on streamflow and stream temperatures in the snow-melt dominated North Fork of the Stillaguamish River. I calibrated the physically based Distributed Hydrology Soil Vegetation Model (DHSVM) and River Basin Model …

Everyone Can Grow! Winter Programming Using An Indoor Horticulture Environmental Education Program To Benefit Military Veterans, Rachel Elam

WWU Graduate School Collection

Working with plants has numerous physical, mental health and well-being benefits for people, and military veteran farming programs have been started to provide these benefits. However, these programs lack activities outside of the Washington State growing season which is approximately May to October. Since these programs are largely meant as ways for veterans to engage in community and peer support, the gap over winter is unacceptable for the purposes of supporting mental health. This project produced a winter environmental education curriculum for military vets, titled Everyone can Grow! (ECG!), and is designed to provide peer support and psychological …

A Needs Assessment Of The Perceptions And Opportunities To Enhance Nature Exploration At Publicly Funded Preschools, Naomi Liebhold

WWU Graduate School Collection

Extensive research supports the benefits of nature exploration in children’s lives. Research also suggests, however, that low-income families and other historically marginalized groups experience multiple barriers to accessing green spaces. In an attempt to counteract this inequality, a needs assessment was performed to understand the challenges and barriers public preschool providers face in regularly leading their children in nature exploration. The target audience of this evaluation was Head Start and Early Childhood Education and Assistance Program [ECEAP] teachers and parents. Along with measuring the challenges and barriers at these centers in regard to nature exploration, this evaluation assessed the resources …

Multifunctional Microgels For Nanoparticle-Based Detection Methodologies, Alyson Silva

WWU Graduate School Collection

In this study, pH-responsive microgel particles, comprised of 2-vinyl pyridine (P2VP) and styrene (PS), are explored as scaffolds to assemble metallic nanoparticles (NPs) for ultrasensitive detection strategies. Microgel particles serve as size-tunable scaffolds to assemble metal (silver or gold) NPs for surface-enhanced Raman scattering (SERS) vibrational spectroscopy. The high sensitivity of SERS arises from the enormous enhancement of the Raman scattering cross sections of molecules adsorbed to roughened metal surfaces, such as metal NPs. Using a sterically stabilized latex of random copolymers of PS and P2VP (PSxP2VPy), this polymer is capable of transitioning to a microgel state through acid-base titration. …

Synthesis Of An Archazolid Based Enzyme Inhibitor, Cooper A. Vincent

WWU Graduate School Collection

The archazolids are a family of natural products that display powerful growth inhibitory activity against a number of human cancer cell lines. This activity has been linked to inhibition of the vacuolar-type ATPase (V-ATPase) and more recently cyclooxygenase (COX) enzymes. Using the archazolid structure as a starting point, several simplified analogues have been prepared and assayed for their V-ATPase and COX inhibitory activity. These simplified analogues were prepared using a novel Suzuki coupling with yields over 80%. They were assayed to investigate both their V-ATPase and COX inhibitory activity. In our assays there was no COX inhibition, while there was …

Not Just Nature, Sarah Kellogg

WWU Graduate School Collection

This field project, entitled Not Just Nature, consists of three parts: the first being a curriculum by the same name. This curriculum, an arts-based workshop series, has been/is being developed to open conversations to interrogate the colonial and white supremacist concepts of nature that have been created in the United States through a variety of means.

The second part of this project is using self as a site of research/critical autoethnography. No field is apolitical, and the creator/researcher will always bring pieces of themselves and their identities to whatever processes they participate in. Thus, throughout my graduate experience I have …

Increased Hydrologic Variability Near The Paleocene-Eocene Boundary (Piceance Creek Basin, Colorado, U.S.A.)), Anna Lesko

WWU Graduate School Collection

The Paleocene Eocene Thermal Maximum (PETM) was a rapid global warming event that occurred approximately 56 million years ago and represents the largest and most abrupt warming event of the Cenozoic Era. The PETM caused mean annual temperatures to increase at least 5°C globally above the already warm, greenhouse climate state of the early Paleogene. The warming and associated perturbation of the carbon cycle had numerous consequences for paleoenvironments and paleobiologic systems. This study investigates the hydrologic response to the PETM within the interior of North America and presents a new d¹³C bulk organic record. This study generates …

Dendroclimatology Of Yellow Cedar (Callitropsis Nootkatensis) And Late Holocene Temperature Variability On The Western Slopes Of The North Cascades In Washington State, Christopher A. (Chrisopher Anthony) Trinies

WWU Graduate School Collection

Subalpine tree growth in the Washington Cascades is often limited by both growing season temperatures and persistence of the winter snowpack, making paleoclimate inferences on temperature alone difficult. Here I expand on three yellow cedar chronologies on the west slopes of the North Cascades and build chronologies for two co-dominant species at one of the sites. I used the VIC hydrologic model to include biologically relevant proxies for water stress, including evapotranspiration deficit, and snow cover in a climate-growth analysis. The co-dominant species, specifically mountain hemlock, showed a climate response reminiscent of a high-elevation, energy-limited environment with an interaction between …

Assessing Coastal Vulnerability To Storm Surge And Wave Impacts With Projected Sea Level Rise Within The Salish Sea, Nathan R. Vanarendonk

WWU Graduate School Collection

Sea level rise (SLR) in the Salish Sea, a large inland waterway shared between Canada and the United States, is expected to be 0.3 to 1.8 m by the year 2100. Uncertainty in greenhouse gas emissions, global ice sheet loss, and other controls such as vertical land movement all contribute to this range. Valuable property, infrastructure, and critical habitats for shellfish and threatened salmon populations are at risk to coastal changes associated with SLR. Additionally, development in Washington State is expected to accelerate through the end of the 21st century adding extra pressure on protecting ecosystems and people from natural …

Structural Studies Of Complexes Of Blood Coagulation Factor Viii, Joseph S. Gish

WWU Graduate School Collection

Factor VIII (FVIII) is a 2332 amino acid glycoprotein with domain organization of A1-A2-B-A3-C1-C2 which is a crucial component of the blood coagulation cascade. After secretion, FVIII circulates in the bloodstream at a concentration of one nanomolar bound to von Willebrand Factor (vWF) which protects FVIII from clearance. In the event of an injury to the bloodstream, FVIII is proteolytically cleaved, releases from vWF and binds to both activated platelet surfaces and activated Factor IX with nanomolar affinity. These interactions increase the rate of blood clot formation 100,000 fold. Hemophilia A is an x-linked recessive disease affecting 1 in 5000 …

Springtime Benthic Fluxes In The Salish Sea: Environmental Parameters Driving Spatial Variation In The Exchange Of Dissolved Oxygen, Inorganic Carbon, Nutrients, And Alkalinity Between The Sediments And Overlying Water, Emma I. Rigby

WWU Graduate School Collection

Recent decades have seen changes to biogeochemical cycles in the Salish Sea, including alterations in water column nutrients, an expansion of hypoxic zones, and bottom water acidification. Marine sediments can be a major contributor to these biogeochemical cycles by exchanging solutes with bottom water. In an effort to understand the sediment biogeochemistry of the Salish Sea further, benthic fluxes of dissolved oxygen (DO), dissolved inorganic carbon (DIC), pH, total alkalinity (TA), and nutrients (ammonium, nitrate+nitrite, phosphate, silicate) between the sediment and the overlying water were directly measured using incubated flux cores at 42 sites in April and early May 2018. …

Paleomagnetic Results From Upper Triassic And Middle Jurassic Strata Of East-Central New Mexico, And Implication For North American Apwp, Masoud Mirzaei Souzani

WWU Graduate School Collection

Two contradictory apparent polar wander paths (APWPs) of North America (NA) for most of Jurassic time have been the subject of many studies since the 1990s, and are important to rectify if in order to constrain the tectonic evolution of the continent. Among various efforts to resolve this persistent issue, additional results from well-dated kimberlite volcanics have been used to support a higher-latitude APWP (Kent et al., 2015), and the controversy was blamed on inclination error (IE) in paleomagnetic results of sedimentary units, most of which are from the U.S. South Western interior. Those paleomagnetic poles define the other, lower-latitude …

Structural Studies On The Mechanism Of Argyrin B And The L12 – L11 Ribosomal Protein Interface, Christopher Swanson

WWU Graduate School Collection

The mechanism of action of argyrin B and the molecular interactions of L11 and L12 has been undetermined and underrepresented in the research of bacterial translation. This work seeks to examine the mechanism of action of argyrin B by performing in vitro structural studies of its interaction with its specific target protein elongation factor-G. We demonstrate that argyrin B inhibits translation, and allows GTPase activity to proceed, contrary to assumptions made in prior research. We determine that ribosome recycling is the likely step through which argyrin B acts as an antibiotic, since translocation is unaffected by argyrin B and association …

Slip And Strain Accumulation Along The Sadie Creek Fault, Olympic Peninsula, Washington, Cody Duckworth

WWU Graduate School Collection

Upper-plate faulting in the Olympic Peninsula of Washington State reflects the interaction of crustal blocks within the Cascadia forearc as well as contributions from various earthquake cycle processes along the Cascadia subduction zone (CSZ). These processes include interseismic coupling, megathrust earthquakes, and aseismic slow slip events. In this study I utilize high resolution airborne lidar, field mapping of deformed surficial deposits and landforms, optically stimulated luminescence (OSL) dating and radiocarbon dating to reconstruct fault slip rates since Late Pleistocene deglaciation on the Sadie Creek fault (SCF), located north of the Olympic Mountains. This mapping reveals the SCF as a ~14 …

Photometric Investigations Of Weathering Rinds And Coatings With Implications For Mars, Kathleen Hoza

WWU Graduate School Collection

Reflectance spectroscopy is a major technique for characterizing the composition of planetary surfaces, and has led to many key findings in planetary geology. In laboratory measurements, reflectance spectrometers typically acquire data using a standard, fixed viewing geometry. Measurements from spacecraft, however, may be acquired at a wide range of viewing geometries, depending on the orientation of the instrument relative to the target surface and the Sun. For many materials, the impact of viewing geometry on reflectance is minor; however, some materials’ spectral signatures can be influenced by these photometric effects. In particular, spectra of weathering rinds and rock coatings are …

Quantifying The Magnitude And Spatial Variability Of Bedrock Erosion Beneath The Sisters Glacier, Washington, Using Cosmogenic 3he Concentrations, Sarah W. Francis

WWU Graduate School Collection

Cosmogenic ³He analyses provide a tool to infer spatial variation of cirque-glacial bedrock erosion. ³He accumulates in bedrock exposed at the surface as a result of cosmic ray bombardment; the concentration of cosmogenic ³He increases with exposure time as well as proximity to the surface. The Twin Sisters range, North Cascades, WA is an ideal location to use cosmogenic ³He to infer cirque-glacial erosion depths and rates, due to the dunite bedrock and the detailed record of Holocene glaciation from the nearby Mount Baker. We used field mapping, lidar data and aerial imagery to identify bedrock …