High Mass X-ray Binaries (HMXBs) are some of the most physically extreme sources in the universe. They comprise of a compact object such as a black hole or a neutron star, and a high mass companion star. The compact object accretes matter from the companion star and forms an accretion disk of material that has temperatures in excess of ten million degrees Kelvin. This accretion disk then radiates out in the X-ray energy band and allows us to ascertain physical properties for the source. However, the very nature of an HMXB constrains the age of the source to a very high degree--this is because the source needs to be old enough for the compact object to form yet it needs to be young enough for the high mass companion star to still have fusion fuel in its core. In this project, we have created star formation histories at the locations of unknown X-ray emitting objects using optical observations from Hubble Space Telescope. These star formation histories determine if there are stars that have an age consistent with HMXBs present. The age of these unknown sources may be associated with these stars, which means they could be HMXBs. We then looked for star formation histories that have constrained ages consistent with an HMXB to try and give more evidence for an unknown object being an HMXB.

Synaptogenesis is the developmental process in which neurons form connections with their appropriate partners. However, the mechanistic bases for synaptic partner matching are largely unknown. To help address this gap in our knowledge about neural circuit formation, we are attempting to identify factors that drive specificity in synapse formation between nociceptive sensory neurons, known as Class IV dendritic arborization neurons (C4da), and their synaptic partners, A08n interneurons in Drosophila melanogaster. We hypothesize that C4da neurons express cell adhesion molecules that serve as specificity factors. Expressing such specificity factors in sensory neurons that do not normally synapse with A08n, for example C3da neurons, should drive spurious synapse formation with A08n. To test this, I used the split Gal4 system to develop transgenic tools for targeting gene expression specifically in C3da neurons. In this system the Gal4 transcription factor is split into its DNA binding domain (DBD) and activation domain (AD) which are independently expressed in overlapping cell populations and assemble to yield functional Gal4 only in cells that co-express both pieces. The complete Gal4 protein can then interact with UAS (upstream activating sequences) elements to drive gene expression. To develop a C3da-specific Gal4 driver I first engineered transgenes containing the Gal4-DBD fused to promoters predicted to be expressed in C3da neurons and other non-da neurons. I generated transgenic fly lines harboring these transgenes via direct injection of DNA into the fly germline. I then crossed these transgenic lines to a fly line that expresses the Gal4-AD element in C1-C4da sensory neurons. I expect to see functional Gal4 only in C3da neurons, which I can test by monitoring Gal4-dependent Green Fluorescent Protein expression. The resulting C3da neuron-specific driver will allow us to test whether ectopic expression of candidate specificity factors in C3da neurons is sufficient to drive synapse formation with A08n interneurons.

Belted Kingfishers (Megaceryle alcyon) are widely distributed across freshwater and marine environments of North America, but the species’ feeding ecology remains poorly studied in marine habitats. In summer 2017, we investigated the behavior and feeding ecology of Belted Kingfishers in the nearshore marine waters of San Juan Island. Our objectives were to assess differences in feeding strategy and success among birds of different ages, to calculate time budgets, and to examine the effects of dynamic environmental factors such as tide and current speed on kingfisher feeding. We conducted focal behavioral observations of adult and juvenile birds at two locations on San Juan Island. Observations on individual feeding success were collected opportunistically during study periods. Overall, adult birds showed a higher success rate and longer average prey length than was observed for juveniles. Feeding success for all age categories was higher at Jackson Beach than at Friday Harbor Labs, suggesting that prey abundance or accessibility may be site specific. Feeding success was fairly consistent over all current speeds but was highest during low tides. Feeding success also showed a diel pattern (highest from 1200 to 1400), differing from prior research in freshwater habitats. Our results are intriguing and demonstrate the need for continued research on how life stage, currents and tidal stage influence marine based Belted Kingfishers and their role in coastal ecosystems and food webs.

X-ray spectroscopic techniques utilize selective x-ray absorption or fluorescence to interrogate the element-specific properties of atoms in a sample of interest, such as oxidation state, ligand identities, and bond lengths. Until recently, x-ray spectroscopic techniques have been primarily limited to large-scale synchrotron facilities employing expensive commercial crystal analyzers. This leads to high barriers to access because of high competition for synchrotron beamtime and the large cost of acquiring optics not presently possessed by the facility. Over the past several years, the Seidler lab has pioneered solutions to both these problems. First, the development of lab-scale x-ray absorption and emission spectroscopy apparatus has enabled a wide range of studies without need for the synchrotron, and second, by designing an inexpensive method for manufacturing the necessary crystal analyzers. I focus here on the second issue, improving the availability and decreasing the cost of the crystal analyzers. Crystal analyzers are at the heart of high energy resolution x-ray spectrometers. They serve the same role as a prism or grating in visible-light spectrometers, that is, they disperse x-rays into their component energies. Our work using temporary vacuum forming of silicon wafers reduces the cost of such optics from $5000 - $10,000 to only a few hundred dollars. Furthermore, the use of vacuum together with modern computer-assisted machining gives the freedom to use either the traditional spherical shape or a superior customized toroidal form, specific to each study. These advances in instrumentation will dramatically speed up analysis of materials and permit feedback on synthesis procedures, battery performance, detection of hazardous chemicals, and catalyst activity.

Mental health services are infrequently used by Arabs and Arab-Americans despite experiences of hardship and emotional distress, which have only become more frequent and intense due to recent state conflicts, population displacements, and patterns of racial/ religious discrimination. In mental health literatures, this "underutilization" of mental health services is often explained in terms of "culture" and "stigma" associated with mental illness. To better understand these issues for Arab populations, we reviewed multiple literatures related to culture, stigma, and mental illness and distilled important lessons for clinical practitioners, researchers, and policy makers. Key findings highlight the diversity of Arab peoples, suggesting important but complex cultural differences that do not easily lend themselves to generic or formulaic clinical responses. Instead, attention to common factors in psychotherapy (e.g., developing shared understandings of the illness experience) and the (mis)alignment of assumptions about the origins of distress (intra-psychic vs inter-personal) and forms of personhood (referential vs indexical) between client and service provider is encouraged. Such considerations in clinical treatment and research can enable more effective psychotherapy for Arab clients and offer important insights into Arab culture and social reticence toward mental illness and its treatment. Structural issues, like limited resources and support for mental health care, were also relevant as they can reinforce stigma by offering ineffective mental health services that fail to ameliorate suffering. Thus, increased resources in terms of funding, training, and infrastructure is essential to creating a more effective mental health system that appeals to Arab populations.

The electrochemical growth of single-crystalline germanium (Ge) nanowires has been previously demonstrated in an aqueous solution for use in complementary metal oxide semiconductor (CMOS) technologies. The motivation for growing these nanowires using electrodeposition is to improve the purity of germanium nanowires relative to traditional synthetic methods. However, nanomaterial growth has been shown to be highly sensitive to both oxygen and water and can lead to impurities, surface layers or morphology changes. . We have grown germanium nanowires in anhydrous organic solution in a nitrogen blanketed electrochemical cell. We have then compared the morphology and material properties of the wires grown in aqueous solution to the wires grown in organic solution to determine the effects of water and oxygen on the wire growth. Improving nanomaterial growth will help in having more efficient computers and cell phones by improving semiconductors.

Modern disease research utilizes two-dimensional (2D) stem-cell tissue culture models, simplified 3D engineered tissues, and animal organisms to study microenvironments and human physiology. However, in vitro platforms often oversimplify the physical tissue niche and animal models do not always accurately represent the function of human tissues. For instance, 2D tissue platforms used to study cardiac biology are limited because they cannot accurately recapitulate the pumping motion of the human heart which is responsible for the circulation or blood. Furthermore, animal models have an under-representative cardiovascular physiology making them inadequate systems for studying human cardiac biometrics. As such, we propose to develop a 3D tissue culture system that can accurately mimic the hierarchical organization of different human tissues. Using our novel flexible cell-sheet stacking technique, we can precisely stack layers of organized cell-sheets to create 3D laminar tissues. Then, these organized laminar tissues can be manipulated by the flexible scaffold into complex 3D tissue shapes using custom-made molds. For example, the human heart is helically aligned cardiac tissue throughout its structure that allows for the generation of intraluminal pressure during ventricular contraction. Inspired by the intricate architecture of human myocardium, this project aims to analyze how varying degrees of cell orientation can influence intraluminal pressure generating function. To account for the hollow and conical nature of the human heart architecture, we have designed a model for casting closed 3D hydrogel scaffolds with a hollow lumen that allows for intraluminal pressure measurements. The proposed model will allow for the determination of the optimal angle of cell alignment that produces the greatest intraluminal contraction. We will validate this platform using a contractile mouse skeletal muscle cell type. This approach can be adapted to model the organization of any contractile muscle tissue and be used to study the function and microstructure of human tissues.

The research project primarily aims at better characterizing how neurons of certain types transform their inputs from “upstream” neurons into outputs to “downstream” neurons. So far in the project, it has been determined that there are major differences between Intratelencephalic (IT) and Pyramidal Tract (PT) neurons on the basis of genetics, morphology, electrophysiology and functionality. We have collected data from two genetically distinct mice. Single cell recordings reveal that PT and IT type neurons are electro physiologically different, in both the locations to which they send their signals in the nervous system and the neuron morphology. Using retrograde tracing (a research method used to trace neural connections), it was found out that PT type send their axons to spinal cord and regions outside of telencephalon region of the brain but IT were restricted to telencephalon region of the brain. Now, my primary focus will be to elucidate how the electrophysiological and morphological characteristics interact. To do this, I will use reconstructions from two photon imaged stacks of their structure imported into a simulation environment called NEURON. Using NEURON, I will try to identify the potential mechanisms that underlines the sensitivity in synaptic integration of the two neuron types. This will provide testable hypothesis for future experimentation. IT and PT type have distinct roles. IT type are sensitive to anti-depressing mechanisms whereas PT type are sensitive to ALS mechanisms. It is this property that will help us create targeted medications.

Interactions between HIV-1 and dendritic cells (DCs) have been suggested to play a role in HIV-1 pathogenesis. DCs are antigen presenting cells that take up, process, and present foreign material to T-cells. Previous research suggests that HIV-1 can exploit this process by binding to DCs, allowing HIV-1 virions to relocate to lymph nodes where infection of T-cells can occur. HIV-1 mediates this interaction through binding of the HIV-1 envelope glycoprotein (Env) to DC-SIGN, a glycan binding protein located on the surface of DCs. Env contains a high amount of oligomannose glycans, enabling Env to act as a binding partner for DC-SIGN. Due to high sequence variation, HIV-1 strains exhibit variability in glycan presentation. A gap remains in our knowledge of where DC-SIGN binding occurs and how glycan presentation across various isolates modulates these interactions. In this study, we applied a combination of biophysical and structural approaches to characterize Env:DC-SIGN interactions across multiple HIV-1 strains. Biolayer interferometry experiments measuring binding affinity demonstrate that DC-SIGN binds with strong affinity towards Env from different isolates. This suggests that DC-SIGN is capable of recognizing different oligomannose glycan presentations and may not have a well defined epitope. However, preliminary results using electron microscopy illustrate that Env glycoprotein structure can be disrupted and altered via binding to DC-SIGN. This appears to be an isolate-specific response, as some strains remain unchanged. Using single particle approaches, we identified potential epitopes in heavily glycosylated regions of Env where additional densities are attributed to DC-SIGN. We infer that in addition to binding HIV Env, DC-SIGN may shield key neutralizing epitopes within these glycosylated regions. Our results provide further insight into the interactions that occur between HIV Env and DC-SIGN, and suggest a mechanism where HIV-1 hijacks DC’s normal immune function allowing HIV-1 trafficking while shielding neutralizing epitopes.

During the Space Race, NASA calculated lunar rocket trajectories by using Euler’s Method to estimate the differential equation obtained by numerically integrating Newton’s Laws of Motion. At the time, computing power was scarce, costly, and primitive. The objective of this project is to develop an interactive MATLAB application that leverages modern computing architecture to accurately and efficiently approximate lunar rocket trajectories based on multiple variables relating to a rocket's journey to the Moon using the Runge-Kutta method. The Runge-Kutta method is a more accurate and sophisticated version of Euler’s method as it uses a multi-stage algorithm that involves slope calculations at discrete time values. This project will bring valuable input to the feasibility of using such numerical methods in approximating lunar trajectories to the industry. The rocket emulated in the program will be based on NASA's Saturn V rocket. Our application will simulate three phases of travel to the moon: achieving Earth orbit, lunar transfer orbit, and lunar orbit. It will consider variables such as time, distance, velocity, acceleration, position, rocket thrust, exhaust velocity, mass flow rate, and aerodynamic drag. The application will allow users to adjust various parameters in real time and see results graphically.

Osteoarthritis, a disease in which the cartilage that cushions joints is lost, affects 27 million people each year. Ankle arthroplasties, or total ankle replacements —i.e., replacement of joint surfaces with artificial materials— have become the procedure of choice for many end-stage ankle arthritis (ESAA) patients. The purpose of this study is to compare foot joint kinematic differences in end-stage ankle arthritis patients pre- and postoperative to receiving a total ankle replacement. Hypotheses over the recovery period include (1) increased range of motion in joint and planar angles, (2) negative correlation between patient pain and ankle function, and (3) ankle function converging towards that of normal gait patterns. Twenty adults with ESAA scheduled for ankle arthroplasty surgery were evaluated preoperatively and at 12 and 24 months postoperatively. A validated five-segment foot model was applied to the affected limb using retro-reflective markers. The model allowed for five three-dimensional joint angles and eight planar angles to be calculated. Subjects completed follow-up surveys self-assessing function and pain preoperatively and at 3, 6, 12, and 24 months postoperatively. Results are limited as the longitudinal study is still ongoing. Thus far, mean joint rotations show increased range of motion at the ankle joint, decreased range of motion between the midfoot and forefoot, and decreased toe splay during the stance phase of gait 24 months postoperative. Correlation between patient pain and ankle function show a trend in decreasing ankle range of motion with increased patient pain, both preoperatively and 24 months postoperatively. Patient pain also significantly decreased between every survey administration time point. These findings will likely aid ESAA patients when considering ankle arthroplasty surgery, informing them about expected recovery and comparing trade-offs between pain and function. Future work includes the ongoing collection of control data for comparison.

Nanowires have shown significant promise as high-capacity, conversion-type lithium-ion battery negative electrodes. Investigating the local properties of these materials during cycling has primarily been done via in-situ transmission electron microscopy or synchrotron-based techniques. Both techniques require highly specialized equipment that is not readily available. Atomic force microscope (AFM)-based measurements of electronic and ionic transport offer another alternative. However, analyzing these electrode materials via AFM has proven difficult due to the large surface variations in Z-height and the flexibility of the wires, which can trap and damage AFM tips. Therefore, sample preparation becomes critical. In this study we screened a variety of preparation methods including epoxies and resins and from those results, determined successful methods to prepare and ultramicrotome samples to create thin slices of electrode that can support analysis via AFM. These images allow for the elucidation of surface characteristics to support future surface functionalization and show that AFM can be applied to the imaging of these types of electrode materials to obtain nanoscale properties. A stronger understanding of local properties in these materials is critical to future developments that are highly anisotropic and require nanostructures.

About 10 million children have difficulties learning to read. If a child cannot see 100% efficiently, it is logical that the child cannot learn 100% of what he or she might otherwise. Yet, in one test conducted by elementary teacher Katie Johnson, “51% of children who passed an eye chart screening still had vision problems that affected their ability to perform at their full potential in the classroom.” This inspired the Educating Young Eyes (EYE) research project to address the core challenge: “How can near vision problems in children such as convergence insufficiency be detected so that parents know action is needed?” As a result, student and faculty researchers at the University of Washington Bothell are developing vision screening tools that can be used by school nurses, teachers, and parents to test for indicators of potential near-vision problems. In Katie Johnson’s book, “Red Flags for Elementary Teachers,” she proposes six activities that serve as “Red Flags” – that is, indicators that a child might have a near-vision problem. We are now creating an app that tests for these Red Flags via a smart phone and/or tablet. In addition to the Red Flags app, we are also working with optometrists and other health care professionals to create an array of portable tools to perform a variety of near-vision screening activities as well as vision therapy games. We are also developing a cloud-based research database to study the efficacy of screening and therapy technologies using data from these apps. Our research has particular benefit for remote and/or underrepresented populations by providing proper vision screening where there is limited access to doctors and/or optometrists. This improves access, provides for more immediate diagnostics, reduces costs for implementation, creates a research-based approach to application development – and most important, helps improve learning outcomes for children!