Conservatively estimated, about one in every ten youth experiences severe depression during adolescence. This is concerning because depression is known to be responsive to prevention as well as to early interventions when accessible to youth. Those who experience early onset depression are at increased risk for other negative outcomes including substance use and suicidal behavior. The effects of depression carry over into young adulthood and are linked with psychiatric and medical hospitalizations, suicidal behavior, and lower educational accomplishments. Youth identified as academically at-risk are particularly susceptible to experiencing depression as well as other co-occurring health risks. Research reveals that family processes serve as a protective influence on the development of depression. Few studies, however, have examined the role of familial risk and protective factors in the development or progression of depression for academically at-risk youth. This research was designed to investigate patterns of depression across time and the influence of family-level risk (family conflict, authoritative parenting style and parental substance use) and protective factors (parental involvement/monitoring and family support) on these patterns. These factors will be compared in terms of their strength of influence on depression. This predictive study is based on survey data collected from a randomly selected, ethnically diverse sample (n=149) of students from two Washington State school districts who were subsequently followed from middle into high school (8th-10th grade). The sample includes youth randomly assigned to the control condition in a school-based prevention study. Depression is expected to be positively associated with family risk factors and negatively associated with protective factors. We anticipate distinguishing differences in the relative influence of family factors on adolescent depression. This detailed examination of key factors influencing adolescent depression will contribute to designing new interventions that are more clearly and specifically targeted, and thus more meaningful, for vulnerable youth and their families.

This report summarizes a method for constructing a Seebeck coefficient tester, the basics behind its operation as well as analyzation of SrxBa1-xNb2O6. Thermoelectric oxides have a very promising and bright future for waste heat recovery, and it is the aim of this project to learn more about them and develop some new materials. The goal of this project is to be able to analyze the Seebeck coefficient of materials at very high temperatures. Current technology is only around 1000 K, and the goal of this project is to be able to measure the Seebeck coefficient of materials to be around 1300 C. The tester is being constructed using our own designs, and a LabView program was created to enable the measurement and operation of the instrument. The setup is fairly straightforward using a 4 point probe test to measure the voltage and temperature difference. For these tests we are using R-type thermocouples instead of the usual K-type thermocouples, as it can handle the very high temperature that is desired. Through developement of a high temperature Seebeck tester there will be greater possibilities in the future for use of various thermoelectric materials.  This report summarizes mainly on constructing the tester to make it fully operational then beginning to obtain measurements, and finally the process of gathering necessary data for accurate measurements.

An inborn genetic disorder, phenylketonuria (PKU) is characterized by elevated phenylalanine (Phe) concentrations that interfere with neurodevelopment, leading to irreversible symptoms such as mental retardation and motor developmental delays if left undetected. Most countries, including the United States, implement PKU testing in newborn screening programs, in order to provide treatment to prevent the onset of irreversible damage. Current methods of detection include tandem mass spectrometry, high performance liquid chromatography, and fluorometric immunoassay. However, these methods require highly technical equipment and trained personnel that do not allow for the tests to be implemented in low resource settings. Thus there is a need for a fully disposable, easy to use, and cost-efficient device for the detection of Phe that can be implemented in areas that lack current Phe detection strategies. My project proposes to develop an enzymatic colorimetric assay for the detection of Phe in a simple paper-based disposable, such that an untrained user can perform and read the test results. Critical to this the incorporation of dry reagents on card. The assay requires a two-step reaction: 1) the conversion of nicotinamide adenine dinucleotide (NAD+) to its reduced form (NADH) in the presence of Phe and catalyzed by phenylalanine dehydrogenase (PheDH), and 2) the conversion of the tetrazolium salt, nitroblue tetrazolium (NBT), into a purple formazan dye due to the presence of NADH and the coenzyme phenazine methozulfate (PMS). Reagent drying protocols have been evaluated for PheDH, NAD+, NBT and PMS for short-term reagent stability. Preliminary data shows NBT and PMS should be stored separately, to avoid autoproduction, while PheDH should be stored with a low concentrated sugar. NAD+ stores well without added stabilizers.

Porous membrane-based lateral flow assays have become commonplace in the diagnosis of a wide range of conditions. Attributes of these assays vary greatly depending upon the application. Many commercially available lateral flow tests (LFTs) employ a 'sandwich' format, where the target molecule is effectively sandwiched between a surface anchored antibody and a labeled antibody. Because small molecules lack multiple epitopes (antibody binding sites), they cannot support the binding of two antibodies simultaneously, and thus cannot be detected using a sandwich format. Competition format assays offer a solution to this problem, but fall short in two key areas: they generally rely on a counterintuitive, inverted user read-out, where a darker signal translates to lower concentration, and are not compatible with chemical signal amplification. My work seeks to improve upon current competition methods by investigating assay formats that generate a colorimetric signal proportional to the concentration of small molecule analyte in a sample. Amplification chemistries have been utilized to improve the limit of detection for small molecules in this new format. Potential future applications of a robust small molecule assay include: rapid detection of cortisol to diagnose post-traumatic stress disorder or Cushing's disease, and field-use testing for active drug components like Δ9 THC in marijuana. Such an assay would have tremendous utility at the point-of-care, and would provide an efficient and effective alternative to expensive lab-based testing.

The thermoacoustic effect provides many benefits compared to current cooling methods. The process can achieve stable and reliable cooling without the use of refrigerants or environmentally hazardous chemicals. Strontium Barium Niobate (SBN) is a relaxer ferroelectric ceramic material that exhibits piezoelectric properties due to its tetragonal tungsten-bronze crystal structure.  A piezoelectric is a material that when subjected to mechanical deformation, undergoes polarization which creates electricity and vice verse.  The purpose of this project was to identify piezoelectric properties of SBN, and utilize an SBN piezo crystal for fine-tuned sound generation in a thermoacoustic cooler. In order to achieve this, understanding the physical phenomena behind thermoacoustic cooling and building a prototype thermoacoustic cooler were first accomplished. From there, identifying the piezoelectric characteristics of SBN and construction of a miniaturized model was initiated. Comparisons were made between the macroscopic and miniature models to determine device properties and characteristics. Device miniaturization reveals a variety of challenges that were previously unobserved in the macroscopic device. A cooling effect was observed and a temperature gradient was achieved in both the macroscopic and miniaturized prototypes. However, the efficiency factor of the micro device was highly correlated to the device geometry and construction. Ultimately, the goal of this project was to achieve thermoacoustic cooling on the micro scale which can only be achieved by understanding the nanostructure and the relationship between grain size and domain polarization mechanisms. Piezoelectrics provide an excellent avenue to achieve this goal due to their high overall efficiency of converting lattice distortions into electrical energy, high curie temperature, their idealized frequency response time and their relative environmental stability.

 Beryllium Oxide is a ceramic material most notably used in the electronics industry due to its outstanding thermal conductivity. Because of this property it is also of interest for use as an insulator under high density plasma exposure. Post exposure the beryllium samples undergo a very specific series of characterization steps. Samples are subject to optical microscopy, in an attempt to identify noticeable surface changes when compared to a control sample. Specific spots show maximum exposure, and are further investigated via XPS. X-ray Photoelectron Spectroscopy shows chemical changes in regions of maximum exposure. Specific depth profiling is utilized to identify possible Deuterium migration, lanthanide exposure, and oxidation effects. XPS is critical for providing detail of the depth of deuterium exposure throughout the material, along with possible deuterium implantation within the crystal lattice of the existing beryllium oxide. X-ray Diffraction comparison between irradiated and control samples shows lattice expansion and residual strain throughout the material. This is a crucial discovery when comparing the impact of the residual strain to the maximum tensile stress. Peak broadening shown on the 2ϴ XRD plot identifies the extent of intergranular strain left by possible deuterium implantation into the beryllium oxide crystal lattice identified through XPS. Thermal conductivity of irradiated samples is tested to ensure that the most redeeming quality of the material is consistent post exposure.

Hair cells (HCs) are the sensory cells of both the hearing and balance systems. HCs that die due to trauma or certain drugs are completely replaced in non-mammalian animals but replacement is extremely limited in mammals, including humans, causing permanent loss of hearing and/or balance function. In the balance system, HCs reside in five sensory organs in the inner ear and respond to changes of head and body position for balance regulation. HCs in the non-mammalian balance system undergo cell “turnover,” a process by which cells naturally die and are replaced. To investigate whether turnover occurs in a mammalian model, I studied utricles, one of the five balance organs, of adult mice. Utricles were immuno-labeled with antibodies to several cell markers, and I collected images of them using confocal microscopy. I observed that actin rich rings, called phagosomes, are prevalent in mouse utricles. These phagosomes seem to be engulfing HCs and likely belong to supporting cells, which surround HCs, instead of macrophage cells that professionally clear dying cells throughout the body. Some phagosomes have HCs inside of them, but most appear empty. This suggests phagosomes target dying HCs or HCs destined to die, and then clear the HCs from the sensory organ. I also observed that many phagosomes have actin rich spikes that may aid in finding the targeted HCs to be removed. These findings suggest that HC death occurs in normal mammalian utricles, which was not previously thought to happen. Because HC numbers remain unchanged in adult mouse utricles, this suggests that new HCs could be added during adulthood. I am currently looking for evidence of HC addition in adult mice. If HC turnover occurs, then the mechanisms responsible can be characterized and potentially manipulated to grow HCs back after damage in human hearing and balance systems.

Every year millions of Washingtonians depend on winter snowfall contributing to their main source of drinking water. Seattleites alone make up 22% of the states population, and 70% of those residents use water from the protected Cedar River Watershed in their homes and businesses. I am analyzing and monitoring snow depth and hydrologic sensors in western Washington maintained by the state Department of Ecology to create a graphical and quantitative model of available water resources that will predict the availability of clean water for years to come. My study will provide a model for the maintenance of sustainable usage for our area as population increases and water availability due to climate change over time decreases. The Cascades’ annual snowfall is diminishing enough to raise concerns about future availability of water and its effects on daily life. Regions of Washington that depend on ice and snowmelt are the most affected by global warming, and some models predict that western Washington may have a problem with water shortages as early as 2040. I will be providing an independent look at the shortages we can expect to face in the near future based on trends over the last 40 years.

 The spins of electrons bound to donors are promising candidates as qubits for quantum information processing. The quantum properties of these donor-shy bound electrons are studied in high magnetic fields while immersed in liquid helium at 4K. For stability reasons, the level of liquid helium in the experiment must be monitored with a sensor. An effective way of implementing a sensor is with a superconducting wire. Super conductors have the property of having zero electrical resistance when they are cooled below a critical temperature. Above this critical temperature, the superconductor has significant electrical resistance. Using these characteristics, a superconducting wire can be used to construct a liquid helium level sensor. When current is run through a thin wire submerged in liquid helium, a relationship can be established between the voltage drop across the sensor and the amount of wire submerged in the liquid helium, allowing the liquid helium level to be measured. Results will be presented on the sensor design and performance.

The ability to optically isolate single gallium arsenide (GaAs) electron donors has many implications both in quantum information science as well as semiconductor physics. However, conventional methods of fluorescence microscopy are fundamentally limited by diffraction, which sets a minimum resolvable feature size preventing the direct optical imaging of nanoscale structures. At the University of Washington Optical Spintronics and Sensing laboratory we are building a super-resolution optical microscope, based on ground state depletion, to isolate single GaAs donors. A critical component of the microscope is the two-dimensional methodical scanning of laser beams over the sample, for which we have elected to use a piezoelectric fast-steering mirror. I have designed a scanning system capable of under 1 nm mechanical resolution, which will be sufficient for our target optical resolution of about 100 nm to isolate single donors. I will present preliminary results on the performance of the test system using a transmission electron microscopy (TEM) grid as a test sample, which will allow us to evaluate the achieved accuracy and resolution of the imaging due to its regular features. Isolating single donors in GaAs using this super-resolution microscopy technique may lead to new insights in how to localize and evaluate impurities such as donors and acceptors for quantum information as well as classical applications.

The Fu lab, in collaboration with the Yager and Lutz labs, develops low cost disposable diagnostic assays, much like the common pregnancy strip, but capable of performing more complex sample processing. Our paper-based assays are capable of automatically sending multiple reagents over a detection zone in sequence. These assays have been developed to perform the detection of markers for diseases such as dengue fever and malaria. My project is to further expand the capability of these assays by providing methods to passively control the flow rate through the detection zone. By optimizing the flow rate for each reagent delivery step, the time to result of the assay can be reduced without sacrificing signal strength. Devices are designed in AUTOCAD and fabricated from nitrocellulose and cellulose using a CO2 laser system. Flow speed within a device is quantified using a fluid marking system, in conjunction with custom video tracking software composed in MATLAB. Our experiments demonstrate several preliminary designs, in which flow is modulated by modifying the geometry of the assay substrate. In one design, a steady flow rate eventually transitions to a secondary, slower steady flow. A second design performs the opposite, where a steady flow rate eventually transitions to a secondary faster steady flow. The third preliminary design incorporates both these results to have a slow steady flow, which eventually transitions to a faster steady flow, and then finally falls back to a slower steady flow again. These flow profiles are well tailored for common protocols currently in use, where fast flowing rinse steps alternate in between slow flowing reagent binding steps.

Public health concern in the U.S and across the world regarding the impact of environmental hazards on human health is becoming more evident as we develop tools to see disparities in exposure and health outcome. Pollutants in the air and water can have lifelong consequences for the quality of lives of many people. Therefore, our toxicology laboratory is examining the result of pesticide exposure and toxicity in children, and how it may cause harm to normal development. Our research centers on studying exposure using blood, urine, and oral buccal samples obtained as part of a Children’s Health study on Yakima Valley. We have determined blood pesticide, urinary metabolite concentrations, cholinesterase activity, paraoxonase activity, and genome wide variation in 200 families. We have analyzed buccal samples from farmworker and non-farmworker families that were collected during different pesticide spray seasons. We are studying these buccal swab samples of children and their parents to identify bacteria present within them. We are utilizing targeted 16S ribosomal polymerase chain reaction (PCR) to determine the phylogenetic composition of the microbiome in saliva samples. The microbiome refers to the vast colonization of microbes within the body. There are more bacterial cells in our bodies than human cells even though they are only about 10% of the total mass. We hope to find a difference in microbe composition and metabolism for samples from agricultural seasons (pesticide use and non-spray seasons), and for child and adult samples. We have already analyzed pilot samples and found consistent results. Recently, we have begun PCR-based analysis and sequencing the remainder of the cohort buccal samples to characterize the diversity of oral microbiomes. If a link is found between the microbiome, pesticides, metabolic traits, and host genotype then we can more fully describe risk and metabolic biomarkers for exposed populations.