Past work have examined children's understanding of race, including their categorization of others based on race, racial preferences, and racial attitudes. Almost all of these studies have only investigated children's racial understanding based on Black and White individuals. In the current study, we wanted to examine whether 4- and 5-year-old White children categorize and hold preferences on the basis of race comparing Asian, Black, and White individuals. Participants were asked "Who do you like the best?" to determine whether they held preferences for individuals based on race, between paired pictures of different-race children. To assess categorization, participants were asked to match pictures of children to exemplars they thought looked most like the children in the pictures. Results demonstrate that children categorize based on race significantly greater than chance t(47) = 5.569, p < 0.001. In terms of preferences, children significantly preferred White over Black children, t(47)=2.801, p=0.007. However, they did not have a preference for Asian versus White children, t(47)=1.219, p=0.229 or Asian versus Black children, t(47)=1.070, p=0.290. Taken together, these results suggest White children have a fairly sophisticated understanding of race; not only do they differentiate between members of their in-group and out-group (significantly differentiating on race between White/Black and White/Asian comparisons), but they also differentiate between other racial groups (significantly differentiating between Asian and Black individuals). Although children categorize and recognize race, this does not mean they always form preferences based on race.

We are using yeast to investigate how the DNA helicase mutation mcm4^Chaos3 interferes with the early events leading to DNA replication and how these replication defects may lead to its role in cancer development. Mcm4^Chaos3 encodes a mutation in a subunit of the MCM helicase, an essential complex required for unwinding double stranded DNA during replication. Mcm4^Chaos3 mice exhibit genomic instability and more than 80% of female mice homozygous for Mcm4^Chaos3 developed mammary tumors (Shima et. al 2007). Further work in yeast identified an origin-specific minichromosome loss phenotype, suggesting the mcm4^Chaos3 mutation may have particular sequence requirements at origins, where DNA replication initiates. To determine the basis of origin sequence specificity in mcm4^Chaos3 function, we had previously performed a plasmid maintenance competition assay using a mutARS317-seq library, containing 500+ plasmids with random single mutations within the ARS317 origin sequence. This assay identified 5 origin sequence variants that performed better in mcm4^Chaos3 yeast than wild type ARS317. To investigate mcm4^Chaos3 interaction with ARS317 variants, I first measured the loss rate for wild type ARS317 plasmids in mcm4^chaos3 vs wild type yeast. As predicted, wild type cells maintained the plasmids better than the mcm4^Chaos3 mutants (16.8% loss rate/generation compared to 5% in wild type). I am currently characterizing the 5 sequence variants, and based on the competition assay data, am predicting to see differences in plasmid loss rates across the ARS317 variants. Understanding the cause for this origin specificity could help us develop a greater understanding of the mechanics involved in DNA replication, genome stability, and cancer-causing mutations.

Large data centers, such as those built by Google, Amazon, and other information technology leaders consume about 1.3% of the world’s energy, of which about 40% is used on electronics cooling [1, 2]. This amounts to 245 TWh per year, which, with the average US price of 12 cents per kWh, amounts to about $29.4 billion dollars spent per year on cooling high heat semiconductors [3, 4]. The work presented here proposes an innovative way to improve this cooling process. The proposed concept features a levitating inner rotor using fluid bearings that result in no physical contact between solid parts, eliminating friction. For the first time, precision-manufactured plastic parts are utilized to achieve both a low cost and a high reliability. The micropump is expected to last in operation for over one million hours Mean Time to Failure. This work emphasizes model-based design verification and optimization to ensure adequate performance for different form factors – so that a drop-in replacement of an air fan passive heat sink can be quickly developed for every microelectronics product. Twenty-four designs and prototypes were used in evaluation of two key criteria in order to optimize the pump’s design. Three separate herringbone geometries, square, beveled-step, and circular, of herringbone grooves were prototyped based on experimentation of optimum groove parameters. These findings helped determine the optimal layer height of 100 micron for use in the micropump design. Finally, the application of a sensorless, brushless DC motor reduces overall cost of the pump and increases efficiency due to the removal of friction.

This research project is part of the Puget Sound Foraminifera Research Project at the Burke Museum, which uses benthic Foraminifera to measure and assess anthropogenic impacts and mitigation efforts in Puget Sound. Benthic Foraminifera, shelled marine protists, are readily preserved in sediments and can be very sensitive to their environment, allowing us to use them as a proxy for changes in marine ecosystems. My project looks at mismatches between Foraminifera that were living and dead at the time of collection to determine whether these discordances can be used to measure anthropogenic ecological change in Puget Sound. In addition, it attempts to validate the use of assemblages containing only dead Foraminifera which were used in the past. Anthropogenic ecological change is a widespread problem and is difficult to measure both the rate of changes and the success of efforts to mitigate problems. We look at Foraminiferal assemblages to establish the health of benthic ecosystems. Sediment samples used in this project are collected by the Washington State Department of Ecology in their annual sampling program. For this particular project, 12 samples from Sinclair Inlet and Bellingham Bay, were collected in Spring of 2015, 2016 and 2017. The Foraminifera were stained with Rose Bengal to identify those individuals that were living at the time of collection and identified to species. The species assemblage from each was then assessed to establish ratios of living to dead individuals and see if the dead population is representative of that of the live population. Results to date indicate that all samples from Sinclair inlet have a smaller ratio of living to dead Foraminifera than other bays. Because the ratios were radically different it may be possible to establish an index to classify embayment health based on live-dead ratios of Foraminifera individuals to use in future assessments.

The purpose of the project is to use benthic foraminifera to investigate the condition of the ecosystem of Possession Sound, Everett, WA, part of Puget Sound. Puget Sound is a polluted water system due to the ports, oil refineries, paper mills, agricultural runoff, and previously, a smelter. Possession Sound itself is home to private properties, a naval station, ports, marinas, and an asphalt plant on the waterfront. Foraminifera are marine protists with calcareous or agglutinated shells (tests) that are readily preserved in sediments. Because they are sensitive to environmental conditions such as bottom water pH, organic and metal pollutants, and change in temperature, they can be indicators of environmental conditions at the sediment/water interface. Calcareous foraminifera exposed to water with decreasing pH have increasing levels of test dissolution, however, agglutinated species don’t dissolve. For this study, sediment samples were collected by the Washington State Department of Ecology; and sub-samples were sent to the Burke Museum. Thirty samples were processed; each was washed through a 63 screen, floated in trichloroethylene to remove the heavier sediment, then picked for around 300 foraminifera/sample. Foraminifera were identified for analysis of their assemblages, condition, and signs of dissolution. These signs are chalkiness, pitting, holes in the shells, and removal of shell layers. The hypotheses are as follows. Dissolution will have increased over time as Puget Sound water quality has decreased in recent years. Worse water quality will result in fewer calcareous species. Foraminifera will be fewer in number since 1997, with a higher proportion being agglutinated species. Results of this investigation will deliver insight into benthic conditions of Puget Sound, specifically Possession Sound, but could also provide useful information for people who rely on Puget Sound’s benthic conditions, such as the oyster and crab industry.

This project focuses on fifteen potentially unpublished species of molluscan fossils—specifically gastropods and oysters—originating from the Sinop-Boyabat sedimentary basin in north-central Turkey. The intent is to identify each fossil in order to date the surrounding rocks, as paleontologists have discovered an unusual mammalian fossil fauna in close proximity. Marine sedimentary rocks from this region accumulated in a small rift basin connected to the Black Sea, and span from the early Cretaceous to the late Paleogene periods (140 to 30 million years ago). The invertebrate fossils were unearthed in the uppermost part of the sedimentary section consisting of shallow water coastal and reef limestones, and calcareous mudstones. Investigations in the Sinop-Boyabat have provided detailed rock descriptions, but additional clues gleaned from the invertebrate identifications will help determine a more temporally restricted age. The fossils must be identified to the generic level and, ideally, to the species level as well. Identification occurred in four stages. First, I separated each fossil in to the taxonomic classes, Bivalvia and Gastropoda. Then I separated them based on shell characteristics and markings such as whorl length, aperture shape and size, and the presence or absence of axial ridges, sutures, or an apex. Next, I took photos of the most intact specimens. The final step has been reading through the literature and attempting to find a fossil description that matches each group. This is the most challenging stage as we cannot find publications that describe any of our specimens. Thus, we are using texts focusing on European and East Asian fossil faunas, none of which include matching identifications. Throughout the search for applicable literature, it became clear that the Sinop-Boyabat invertebrate specimens have not been studied before and many are new species.

Flowering plants exhibit striking diversity in their floral symmetry due to independent genetic changes throughout their evolutionary history. Diversity is also observed within the flowers of genus Rhododendron, which displays a variety of radially and bilaterally symmetric flowers across its approximately 1000 species. Floral symmetry is governed by an interaction between one TCP transcription factor, CYCLOIDEA (CYC), and two MYB-class genes, RADIALIS (RAD) and DIVARICATA (DIV). This interaction initiates when CYC is expressed in the floral meristem, leading to the activation of RAD in the dorsal domain. RAD then antagonizes DIV activity in the dorsal regions, leading to radial symmetry. In other flowering plants, duplications in CYC have been associated with changes in floral symmetry, but the role of RAD and DIV remain unstudied. A number of transitions to and reversals from radial symmetry have occurred throughout Rhododendron from a bilaterally symmetric ancestor. Focusing on RAD and DIV, the goal of this study is to better understand the evolutionary history of these floral symmetry genes in rhododendrons, and their correlation to floral symmetry changes. I sampled eight different species throughout Rhododendron in addition to various outgroups and reconstructed phylogenies of these genes. I obtained sequences from genomic and transcriptomic databases, and used these sequences to design primers for amplifying and sequencing these genes from laboratory samples from wild and cultivated specimens. I found two distinct copies resulting from one duplication, in both RAD and DIV. In future studies, we will expand our sampling of species to investigate the phylogenetic placement of the origin of these duplications in tandem with changes in flower symmetry, to determine whether duplications in RAD or DIV are associated with symmetry changes as has been shown for CYC.

Fluorescent nanocrystal quantum dots (QDs) show promise for biomedical application, but are often negatively associated with cellular toxicity. To investigate the potential of QDs as a biomarker in the brain, a systematic evaluation of potential toxicity is necessary. In this study, we evaluated QDs with various surface functionalities and assessed toxicity as a function of concentration and exposure time. We utilized organotypic brain slices obtained from healthy postnatal day 14 (P14) rat pups. Four cadmium selenide (CdSe)-core QD conjugates were evaluated: mercaptopropionic acid (MPA), hydroxyl-polyethylene glycol (PEG-OH), amine-PEG (PEG-NH2), and methoxy-PEG (PEG-MeO) at 0.01, 0.1, and 1.0 μM concentration. Cell toxicity was primarily quantified by measuring lactate-dehydrogenase (LDH) production, which is an indicator of cell death, over a five-day period. Results were supplemented with confocal microscopy analysis of two imaging-based assays: propidium iodide, a stain of the nuclei of dying cells, and fluoro-jade C, a stain of degenerating neurons. QD-MPA treated slices had 7-8% greater toxicity than the non-treated (NT) control. All other functionalities were comparable to the NT control except QD-PEG-OMe, which had 3% lower cytotoxicity suggesting a possible neuroprotective effect. Alternatively, certain functionalities (MPA, NH2) may show lower than expected toxicity due to aggregation before cellular uptake. Compared to 0.1 μM concentrations, 0.01 μM QD treated groups had around 4% lower toxicity. Similarly, 1-3% greater toxicity was observed in extended QD exposure conditions (24h) versus shorter exposures (1h). Results show that toxicity is dependent on surface chemistry, concentration, and exposure time. This is useful in identifying QD conjugates with low cytotoxicity in the developing brain. Understanding QD toxicity can lead to rational design of QDs for site and cell-specific uptake in the brain as a biomarker of neurological disease severity, improving the selectivity of current imaging techniques and providing a powerful diagnostic with regards to diseased cell fate.

Nuclear coercion rests on the threat of force to compel a demand. Some strategists contend that nuclear coercion does not work between nuclear adversaries. The theory of the nuclear revolution posits that military victory is not possible in the nuclear era, and therefore military power cannot advance political ends. Others maintain that nuclear coercion is indeed possible, and the nuclear balance of power between adversaries shapes political outcomes. This study explores whether strategic superiority generates coercive leverage in crisis bargaining. It employs a qualitative case study analysis of Soviet decision making during the Cuban Missile Crisis to test rival theories of nuclear strategy.

Rapamycin is a drug that has shown to extend lifespan across many model organisms including laboratory mice. Although the drug’s effect on extending lifespan has been investigated, it’s effect on transport of metabolic hormones across the blood-brain barrier (BBB), including insulin, are unknown. Rapamycin extends life by impacting whole body metabolism by acting as a caloric restriction mimetic inhibiting a cellular signaling molecule, mammalian target of rapamycin (mTOR). Insulin transportation into the brain via the BBB has been seen to increase during periods of starvation. Therefore, we wanted to investigate whether treatment of rapamycin would increase insulin transport across the BBB into the brain by inducing a 'starvation state'. I gave IP injections of 8 mg of rapamycin per kg body weight to two-month old male CD-1 mice for two weeks daily. A control group was given IP injections of vehicle for the same duration and amounts. At the end of the two weeks, I gave the mice IV injections of radioactive insulin and albumin (a vascular space marker) that circulated for various times (1-10 min) before collecting blood samples and performing whole brain removals. The radioactivity in the serum and whole brain was measured. The rate of uptake of the radioactive insulin into the brain was calculated and compared between chronic rapamycin treatment and control groups. Two-week rapamycin treatment showed elevated insulin levels in whole brain tissue when compared to the control group suggesting that rapamycin may have an effect on insulin transport.

Oncology trials often entail high-stakes interventions where the potential for morbidity and for fatal side effects, as well as for life-prolongation or cure, intensify bioethical issues related to informed consent. These challenges are further compounded in multistage randomized trials, which are increasingly prevalent in oncology. We sought to elucidate the major challenges in achieving true patient understanding of informed consent documents in high-stakes oncology trials in general and the best consent practices for multistage randomized trials in particular. We queried the PubMed database for original studies published on 1-1-1990 to 4-1-2017 that focused on readability, quality, simplicity, complexity or length of consent documents, sickness level of participants, or interventions and enhancements that influence informed consent. Additional articles were identified through comprehensive bibliographic review. Twenty-four articles were retained as the basis for the narrative review; 18 enrolled participants and 6 examined samples of consent documents. This body of literature provides useful information about the pitfalls of the informed consent process as currently practiced in most high-stakes interventional oncologic trials. The understanding level of study participants is examined as impacted by the readability of documents, the complexity of the documents, the length of the forms and the “what’s at stake” nature of oncology trials. The length of the informed consent documents has increased from 338 in 1987 to 3982 in 2010 and patient understanding has been shown to be inversely proportional to the page count of the documents. Additionally, patients’ belief in the “therapeutic myth” also has a negative effect on true patient understanding. The unique challenges of obtaining consent in multistage trials are noted and examined. Though no studies specifically addressed the additional problems posed by multistage randomizations (such as change in risk-benefit ratio due to time-varying treatment responses or organ toxicities), the findings are likely applicable and especially relevant in that context. 

There are several approaches to treating Acute Myeloid Leukemia (AML) relapse after an allogeneic stem cell transplant. We were curious about the efficacy of the different types of treatments commonly deployed for patients with post-allograft AML relapse. Eligible patients included those who underwent allogeneic stem cell transplant for a diagnosis of AML and then relapsed between 1/1/2005 and 12/31/2015. We abstracted information about their treatments, GVHD status, immunosuppressive drugs, response (ie relapse or remission) events and vital status from their medical records. Among 120 patients, we found a median number of 2.6 and a mean of 2.9 relapse-directed lines of treatment, while 21% received no treatment. The types of treatment deployed were tightly correlated with the patient’s malignant blast count and the time that had elapsed since first transplant. There were 74 induction chemotherapy attempts, 64 hypomethylating therapy prescriptions, 19 donor lymphocyte infusions (DLI), and 16 second transplants, for example. Ongoing work includes completing data entry on the remaining 186 subjects, and analyzing the relative efficacy of the different treatment options. Importantly, we found that patients whose relapse presented with very low-level disease burden (<5% malignant blasts) still had a dismal prognosis, with only 20% being alive in remission at last follow-up. By contrast, patients relapsing with >5% blasts had an even worse prognosis – only 7% alive in remission at last follow-up. Closer surveillance for post-transplant relapse might catch more patients relapsing at low disease burdens. Initiating treatment when the disease burden is low may be more effective. Our ongoing work will identify the best sequences of treatments (leading to the longest relapse free survival), taking into account the blast burden, time elapsed since transplant, and other predictive factors.
 

Drug delivery to the brain is difficult due to the strictly regulated barriers and a complex microenvironment. Nanoparticles can help overcome these barriers to delivery by providing highly stable and tailorable platforms. Charged nanoparticles have an electrostatic double layer that ensures colloidal stability, while sterically stabilized particles have ligands (e.g. polymers, surfactants) that improve colloidal stability. In the brain, changes in the local pH, temperature, and ionic composition of the surrounding media, either in normal physiological function or in the case of injury, can change the stability of suspended nanoparticles. However, there are limited systematic studies of nanoparticle stability in representative brain microenvironments. This research focuses on how calcium concentration, a key ion in the brain microenvironment, influences aggregation kinetics in artificial cerebrospinal fluid (aCSF) and how other physiological factors (temperature, pH) impact nanoparticle aggregation kinetics. We designed an experiment to examine how divalent cations (calcium, magnesium) alter the aggregation kinetics of both carboxylated polystyrene (PS-COOH) and poly(ethylene glycol)-coated polystyrene (PS-PEG) nanoparticles in physiologically relevant conditions. We hypothesized that the PS-PEG nanoparticles would remain stable at physiological conditions, while the PS-COOH nanoparticles would experience aggregation. Dynamic light scattering (DLS) was used to characterize the nanoparticle hydrodynamic diameters. Each experiment was performed in aCSF at a range of pHs (5.5, 7.2, 8.5) and temperatures (23, 37°C). We demonstrate that PS-PEG nanoparticles have higher aggregation thresholds than PS-COOH nanoparticles. We also show that higher temperatures accelerate aggregation kinetics of both particle types. Acidic environments seem to provide a protective effect for PS-PEG nanoparticles, while basic environments can cause catastrophic aggregation even when the particles are stabilized with PEG. Future research will examine the effect of PEG chain length (2k, 5k, 10k) as well as PEG coverage density on aggregation kinetics in the brain.

Metabotropic glutamate receptor 5 is a receptor for glutamate, one of the major excitatory neurotransmitters. Glutamate serves many functions throughout the nervous system, such as activating microglial cells, the immune cells of the nervous system. Microglial activation then initiates the release of cytokines. Cytokines are responsible for triggering signaling cascades that lead to pro- and anti-inflammatory immune responses. Although cytokines play an important role in mitigating disease and injury states in the nervous system, excessive cytokine release may cause ongoing neuroinflammation and neurotoxicity through a complex series of pathways. mGluR5 deficiency has been linked to neurotoxic cytokine release as well as neurological disorders such as Fragile X Syndrome, autism spectrum disorders, and schizophrenia. The Nance lab established the first mGluR5 rat knockout (KO) colony to investigate the links between glutamate dysfunction and neuroinflammation. This project quantitatively analyzes the levels of pro- and anti-inflammatory cytokines in mGluR5 KO pups, across gender and genotype. RNA was isolated from mGluR5 postnatal day 12 (P12) to P14 KO, wild-type (WT), and heterozygous (HET) pups and converted to cDNA. RT-PCR was performed to analyze mRNA levels of TNF-α, IL-1-β, IL-6, TGF-β, IL-10, GCP-II, and IL-12-β cytokines. 2-ΔΔCt values demonstrated 2 to 4-fold changes in these cytokines due to differences in genotype and gender, relative to the housekeeping gene GAPDH. Characterizing cytokine profiles leads to greater understanding of the interplay between inflammation and ongoing injury in the developing brain, and may elucidate pathways for therapeutic intervention. Identifying specific cytokines linked to increases in neuroinflammation will also provide further insight into the roles that glutamate, and glutamate receptor deficiency, play in the development of neurological disease.

Quantum dots (QDs), fluorescent semiconductor nanocrystals, can be used as a biomarker and diagnostic tool for central nervous system (CNS) diseases because of their unique physical properties. To serve as an effective diagnostic platform, QDs must diffuse from the point of access to a desired target within the brain. To maximize diffusion within the CNS, QDs need to remain monodisperse, and avoid any adhesive interactions or steric limitations imposed by the brain microenvironment. Therefore, characterization of physicochemical properties and overall colloidal stability in physiologically relevant solvents is required to understand QDs diffusivity within the CNS. A methodology based on dynamic light scattering (DLS) was employed to assay QD hydrodynamic diameter, where increase in particle size served as an indicator of QD aggregation and instability. Time dependent stability was investigated by incubating QDs in 1xPBS, a low concentration salt solution, and artificial cerebrospinal fluid (aCSF), a more complex medium that mimics in vivo interstitial fluid. Measurements were recorded for 24 h at both room and physiological temperatures. Compared to 1xPBS, QDs without poly(ethylene glycol) (PEG) ligands showed more rapid and significant aggregation in aCSF while PEGylated QDs remains relatively stable in both mediums. To explore the rate at which QDs initially aggregate, particle size was measured for the first 200 seconds post-incubation in solutions of varying concentrations of calcium ion, an ion which plays an important role in many neuronal processes and is often found in abnormal amounts in the brain in diseased states. The results showed that the rate of initial aggregation is concentration dependent and is diminished by PEGylation. With further analysis of QD stability in CNS relevant mediums, this methodology will aid in establishing key properties that govern QD behavior in the brain microenvironment, which can be used to employ QDs as an effective biomarker for brain diseases.

Traditionally, drugs intended for use in the central nervous system (CNS) have lower success rates than drugs used to treat any other part of the body, with very little drug reaching target disease cells in the brain. This limited success is brought about by several physiological barriers, including the blood-brain barrier (BBB), the blood-cerebrospinal fluid barrier, and the highly dynamic and densely packed brain microenvironment. Nanoparticles, if designed properly, have been shown to bypass the BBB and diffuse into the brain extracellular space (ECS), making them a promising option as drug delivery vehicles for CNS diseases moving forward. However, evaluating a nanoparticle’s ability to overcome these barriers both in vivo and ex vivo remains difficult because the brain microenvironment is dynamic, heterogeneous, and variable from brain to brain. To combat this, we aim to develop a gel model of the brain microenvironment that can be used to assess the diffusive ability of nanoparticles in vitro. The model consists of a low concentration (0.4%) agarose gel loaded with proteins found within the brain ECS. To ensure the method used to construct the gels is both controllable and reproducible, characterization of the gels was carried out using a combination of rheological and multiple particle tracking experiments. Rheological experiments determine the gel’s bulk mechanical properties, while multiple particle tracking using probe nanoparticles characterized the gel’s pore size distribution. The insight gained from these characterization techniques allows us to make more informed predictions of how various nanoparticles will diffuse when loaded into these gels.

Researchers often deal with massive longitudinal data sets. Currently-available tools visualize large amounts of longitudinal data but are very rigid or require strict formatting of the data to process it and translate it into visuals. We created an online longitudinal data visualization tool that can be customized by its user in nearly every way. We aimed to visualize trends in sequentially-applied anti-cancer therapies in a cohort of patients from the Fred Hutchinson Cancer Research Center who received cell transplantation for leukemia, but later relapsed. The researchers wanted to visualize multiple disease statuses in parallel to the treatment-and-response trajectories. My objective was to make this tool as customizable as possible, so that it could be used by other researchers with different longitudinal data. I first created a prototype using JavaFX that allowed the user to construct customizable swimmer plots. My design allowed the user to customize visuals such as the colors, shapes, and scale of events in the swimmer plot. To further improve the dynamic features and efficiency of this tool, I approached the developers of Oncoscape, an open source JavaScript software that allows for data visualization and exploratory data analysis, to refine and incorporate my tool into the Oncoscape suite. The current iteration of our tool provides unparalleled flexibility to accommodate any longitudinal data set. It allows researchers to select subsets of subjects based on multiple shared characteristics, allow simultaneous visualization of two or more sequences per subject, and allow researchers to zoom in to a granular level of detail for each subject. This tool will provide doctors a means to quickly study which treatments were administered in which order to similar, historical patients, and their associated outcomes. Thus, by disseminating this tool, we will help doctors make better therapeutic decisions during key moments in an individual patient’s treatment course.