Physical Sciences and Mathematics Commons^™

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 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.

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 …

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 …

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 …

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 …

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 …

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. …

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, …

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 …

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 …

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 …

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 …

Chemical And Morphological Variance In Vitriclastic Shards From Iodp Site U1437: Inferences About Source Regions And Eruptive Mechanisms, Larissa Sleeper

Geology Graduate and Undergraduate Student Scholarship

International Ocean Discovery Program (IODP) Expedition 350 recovered roughly 2000 meters of volcaniclastic material. This paper focuses on the first 100 meters of this core which was almost entirely composed of tuffaceous mud. Tiny (micron) vitriclastic shards within this mud were analyzed to determine their chemistry and their morphology to make inferences about their source environment and eruptive mechanisms.

Spatiotemporal Variability In The Climate Growth Response Of High Elevation Bristlecone Pine In The White Mountains Of California, Andrew Godard Bunn, Matthew W. Salzer, Kevin J. Anchukaitis, Jamis M. Bruening, Malcolm K. Hughes

Environmental Sciences Faculty and Staff Publications

Tree-ring chronologies from bristlecone pine (Pinus longaeva) are a unique proxy used to understand climate variability over the middle to late Holocene. The annual rings from trees growing toward the species’ lower elevational range are sensitive to precipitation variability. Interpretation of the ring-width signal at the upper forest border has been more difficult. We evaluate differences in climate induced by topography (topoclimate) to better understand the dual signals of temperature and moisture. We unmix signals from trees growing at and near the upper forest border based on the seasonal mean temperature (SMT) experienced by each tree. We find that trees …

Environmental Inequality Dataset, Aran Clauson, Debra J. Salazar, Troy D. Abel

College of the Environment on the Peninsulas Publications

The Disaggreated RSEI model data (also known as RSEI-GM, or Geographic Microdata) version 2.3.4 was downloaded from the Amazon Web Service created by EPA. The RSEI-GM provides detailed air model results from EPA’s Risk-Screening Environmental Indicators (RSEI) model. The results include chemical concentration, toxicity-weighted concentration and score, calculated for each 810 meter square grid cell in a 49-km circle around the emitting facility, for every year from 1988 through 2014. The data can be used to examine trends in air pollution from industrial facilities over time and across geographies. In order to allow for evaluation of toxic-weighted concentration over time, …

A Multidecade Experiment Shows That Fertilization By Salmon Carcasses Enhanced Tree Growth In The Riparian Zone, Thomas P. Quinn, Helfield M. James, Catherine S. Austin, Rachel A. Hovel, Andrew Godard Bunn

Environmental Sciences Faculty and Staff Publications

As they return to spawn and die in their natal streams, anadromous, semelparous fishes such as Pacific salmon import marine‐derived nutrients to otherwise nutrient‐poor freshwater and riparian ecosystems. Diverse organisms exploit this resource, and previous studies have indicated that riparian tree growth may be enhanced by such marine‐derived nutrients. However, these studies were largely inferential and did not account for all factors affecting tree growth. As an experimental test of the contribution of carcasses to tree growth, for 20 yr, we systematically deposited all sockeye salmon (Oncorhynchus nerka) carcasses (217,055 individual salmon) in the riparian zone on one …

The Planet, 2018, Fall, Emily Stout, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

Deblurring Images, Jamie Mcmullen

WWU Honors College Senior Projects

Let the matrix B be a blurred version of a sharp image represented by the matrix X. Given B, we would like to recover X.

To accomplish this, we construct linear models of the blurring process that produced B from X. The idea is that we could then reverse the blurring to reproduce the original image.

For example, if the blurred image satisfies

B = CXR^T

for some invertible matrices C and R, then we could recover X as

X = C-¹B(R^T)^-1.

However, the blurring model …

The Energy Imbalance Market: Environmental Benefits Of Regional Market Integration In The West, Kristen E. Tarr

WWU Honors College Senior Projects

Compared to other regions of the United States, the Western electric grid is fragmented and balkanized, due to lack of regional market coordination. As the West anticipates the growth of renewable energy, there is an evident need for regional market interconnection. The Energy Imbalance Market (EIM) is the first sub-hourly regional power-trading market in the West, allowing Western utilities to buy and sell electricity across the diverse geographic region (EIM, 2018a). By tapping into the flexibility and diversity of regional production profiles, the EIM reduces the variability and intermittency of renewable power. According to the 2017 quarterly benefits report, from …

Enhancing Student Ability To Transfer Energy Concepts In Postsecondary Science Education Through Explicit Instruction Of Concepts, Student Self-Reflection, And Guided Practice In Knowledge Transfer, Jim Harmon, Lauren Gray

Scholars Week

While concepts of energy and matter apply across science disciplines, students have difficulty transferring their knowledge of energy concepts from one science discipline to another. Traditionally, instruction of physical sciences, chemistry, and life sciences are presented independently of one another; with energy concepts introduced in isolated contexts and with differing emphases. Two instructional strategies have been shown to improve student transfer of knowledge: metacognitive student reflection, and explicit framing of concepts. This study integrates these instructional strategies into an introductory physics course for non-science majors as a series of instructional interventions, measuring student ability to transfer knowledge of energy concepts …

Locate And Mitigate The State Of Nitrate: Assessing Potential Sources Of Nutrients In Tributaries To The Nooksack River, Alyssa Peter, Melanie Roy

Scholars Week

Anthropogenic activities greatly increase the amount of nitrogen entering our environment. While this allows for increased agriculture production, excess nitrogen raises health concerns for humans and ecosystems. Understanding the sources of excess nutrients is necessary for effective efforts to reduce them. We aimed to understand nutrient fluxes through tributaries to the Nooksack River, in particular, to what extent are excess nutrients arriving to northern Whatcom County from Canada via both surface and ground water. We collected water samples from three creeks fed by the central portion of the Sumas-Blaine aquifer (Kamm, Fishtrap, and Bertrand), two situated at the southern edge …

Connection: An Autism-Focused Dating App, Cyrena Johnson

Scholars Week

30% of US internet users 18-29 use dating apps to find partners. Meanwhile, only 9% of adults with autism are married—and there are no popular dating apps designed for ASDs. We propose the app Connection, a dating app designed for the autistic community. Using queries and informal analysis, we created possible features and prototype displays for Connection to show its future application.

Modeling And Forecasting Crime Patterns In Bellingham, Washington, Zachary Domingo, Eric Shoner

Scholars Week

Our purpose is to use time series analysis to model and forecast the underlying dynamics behind crime in Bellingham, Washington. Using recent monthly data from the Bellingham Police Department, we considered singular spectrum analysis and autoregressive moving average modelling techniques to estimate significant deterministic patterns in the data. After examining the multitude of data provided, we narrowed down to two categories of crime: alcohol offenses and domestic violence. We created two time series models for each category and compared them to each other. The better performing model was used to forecast the number of crime incidents for ten months and …

Short-Term Volatility Curve Predictions Using Singular Spectrum Analysis, Nick Odell

Scholars Week

This project aims to produce accurate volatility forecasts, using high-frequency financial time series data. The primary mathematical methods used are Functional Data Analysis, time series analysis techniques such as Autoregressive Models and a comparison between Multi-variate and Uni-variate Singular Spectrum Analysis. These results aim to be useful for financial risk quantification.

Modeling Current Flow In Nanoparticle Doped Polymer Film Systems, David Seaman, Joshua Spradlin, Janelle Leger, Armin Rahmani

Scholars Week

Nanoparticle-doped polymer systems have elicited great interest for their ability to exhibit an electrical hysteresis, which can be applied to bistable organic memory devices. Such hysteresis is characterized by the ability maintain different currents at the same voltage, upon increasing and decreasing the voltage. Developing a successful theoretical and computational model for this effect could provide insights into what mechanisms are driving the hysteresis. However, while there has been interest in these systems for two decades, there are still open questions regarding modeling their operation mechanism. In this work, we explore a method of modelling these systems that approximates the …

New Reactions Of Strained Allyl Silacycles, Elizabeth Cummins

Graduate Student Symposium

Ring-strained allylsilanes exhibit both electrophilic and nucleophilic characteristics, allowing for simultaneous activation and allylation of carbonyl compounds. Results are presented describing an optimized synthesis of certain allylsilacyclobutanes and their use in several selective carbon-carbon bond forming reactions.