The purpose of our research is to better understand older adults’ perceptions about fall detection devices. When an older adult experiences a fall, the results can be dramatically life altering or even fatal compared to an individual in a different age group. This led us to question what views older adults have about existing measures in place to monitor and analyze falls, such as fall detection devices or other technologies, as well as what demographic factors may influence these views. Using data from a parent study, we are currently in the process of analyzing focus group transcripts to compare perceptions of older adults from high and low socio-economic status using qualitative descriptive methods. We are analyzing transcripts for common themes that may lead to the identification of areas for further study. By studying older adults’ perceptions of fall detection devices, we hope to gain a better understanding of their needs and preferences when it comes to such devices. We hope exploring and understanding demographic or other factors that affect these perceptions may lead to more open conversations on falls, and thus better our ability to customize fall detection devices and their features, and fall prevention plans for older adults.

Proton-coupled electron transfer (PCET) occurs in a variety of oxidation/reduction reactions. This thermodynamically-coupled transfer of an electron (e–) and a proton (H⁺) is important for many reactions, including catalysis and energy generation, and may occur through different mechanisms. Zinc oxide (ZnO) nanoparticles are useful for studying factors that influence the rates of PCET reactions in at metal-oxide surfaces. The ZnO nanoparticles used in this research have been well characterized and, as a colloidal solution, can be treated as molecule-like reactants in experiments. The ZnO nanoparticles described in these experiments are capped with dodecylamine (DDA), and then dispersed into air-free toluene, an aprotic solvent. The use of an aprotic solvent is important to ensure that the e–/H⁺ are transferred from the nanoparticle. When these nanoparticle solutions are irradiated with above-bandgap radiation, an electron is excited into the conduction band. This leaves a hole in the valence band that, from previously demonstrated research, is immediately quenched by EtOH left over from synthesis; EtOH provides both an electron and a proton, keeping the nanoparticle neutral. When the reduced and protonated ZnO nanoparticles are reacted with 2,4,6-tri-tert-butylphenoxyl (^tBu₃ArO·), an electron and a proton are transferred from the reduced ZnO nanoparticle to the ^tBu₃ArO·, yielding the corresponding phenol, ^tBu₃ArOH. The kinetics of this reaction are monitored using laser flash photolysis. The rates of PCET are affected by the reduction potentials and the pKa of the reactants. The reduction potentials of the nanoparticles may be tuned by changing the particle size. Initial results also show the concentration of the capping group affects the rate of PCET. We are investigating how these factors, reduction potential and capping group concentration, influence the rate of PCET from reduced and protonated ZnO nanoparticles.

Women with a history of sexual victimization often have higher rates of alcohol consumption and sexual risk-taking than women with no history of sexual victimization. One explanation proposed for these associations is the self-medication hypothesis which says that women with sexual victimization histories engage in drinking and risky sexual behavior to cope with distress or to increase positive affect. Although popular wisdom and research studies link alcohol and sexual risk-taking, sexual assault victims often experience difficulty with sexual intimacy. Specific motives to consume alcohol in order to cope with or further enhance sexual behaviors have not been examined. Further, it is not known how a history of sexual assault would impact sex-related drinking motives and whether these motives would mediate the association between sexual assault history and both alcohol consumption and risky sexual behavior. We are currently in the process of recruiting undergraduate women through the University of Washington Psychology Department’s Online Subject Participation Pool. Women are asked to complete a forty-five minute online survey about their drinking patterns, history of sexual experiences and sexual assault, and endorsements of sex-related drinking motives. Data collection will be complete at the end of winter quarter, after which we will conduct mediation analyses using bootstrapping to test our hypotheses that sex-related drinking motives will mediate the relationship between a history of sexual victimization and both alcohol consumption and sexual risk-taking. We expect that these motives will partially mediate the relationships between a history of sexual victimization and both alcohol consumption and sexual risk-taking. Results will help inform effective interventions tailored toward survivors of sexual assault.

Compound I is the intermediate responsible for substrate oxidation in the catalytic cycles of a variety of heme-containing metalloenzymes, such as peroxidases, oxygenases, and importantly, cytochrome P450s. Cytochrome P450s, through compound I, oxidize approximately 75% of foreign substances that enter the body, such as pharmaceuticals and chemicals from the environment, so there is an interest in the mechanism by which this reaction occurs. The goal of this project is to probe the potential reversibility of Compound I formation, a step traditionally thought to be irreversible. Due to its stability and availability, horseradish peroxidase (HRP) was used as the model enzyme. In the case of HRP, hydrogen peroxide is reduced to water at the heme cofactor, while oxidizing a variety of substrates. In the presence of an oxidant and the absence of a substrate to oxidize, hydrogen peroxide coordinates to the iron of the heme, the O-O bond is cleaved, which forms water and compound I. A key experiment reacts HRP with unlabeled H₂O₂ in ¹⁸O-labeled water, and determines whether mixed-labled H₂O₂ is formed. The presence of mixed-labeled H₂O₂ indicates that there is reversibility of the O-O bond cleavage that forms compound I. The existence of mixed-labeled H₂O₂ is ascertained by first removing HRP by filtration, leaving the H₂O₂ in the filtrate. This is followed by the addition of a water soluble phosphine. In this case, the phosphine cannot be oxidized by Compound I, but can readily react with free hydrogen peroxide in solution to give the corresponding phosphine oxide. Mass spectroscopy is used to determine whether the phosphine oxide has incorporated the ¹⁸O label. Results show that when the experiment is performed in the presence of ¹⁸OH₂, there was no observable increase in the intensity of a peak corresponding to ¹⁸O-phosphine oxide, so reversibility of Compound I formation was not confirmed.

Research indicates that alcohol consumption and sexual victimization history, separately, are related to women’s increased unprotected sex risk. An additional question is whether partner relationship potential (i.e., likelihood of having a romantic relationship) interacts with victimization history and alcohol consumption in their association with risky sexual behavior. Participants were 436 female heavy episodic drinkers, aged 21-30, at elevated risk for sexually transmitted infections. They completed background questionnaires that assessed sexual victimization and an alcohol administration protocol (control or BAC=.10). Next, they projected themselves into a hypothetical sexual scenario, which manipulated relationship potential (high or low) with the man in the story. Following the scenario, participants listed their reasons for and against having sex, knowing no condom was available, and rated the strength of these reasons on a 1 (not at all strong) to 7 (extremely strong) scale. We computed two difference scores. First, the number of reasons listed against having sex was subtracted from the number of reasons listed for sex. Second, the strength of the reasons against having sex was subtracted from the strength of the reasons for having sex. Higher scores indicated that women listed more reasons for having sex than against and perceived reasons for having sex were stronger than reasons against, respectively. We regressed both outcomes on sexual victimization severity, alcohol dose, relationship potential, and all interactions. Analyses indicated a significant 3-way interaction for reason strength, but not number of reasons listed. For women with high victimization severity who received alcohol, relationship potential was positively associated with stronger reasons for having sex, which is likely indicative of greater sexual risk. Results have implications for risk prevention programs and suggest the importance of providing risk information for women with victimization histories who consume alcohol prior to sexual encounters and perceive high relationship potential in their sexual partner.

For centuries, mankind has used adhesives as a means of joining materials together. A simple technology, adhesives bond materials, distribute stress, and improve flexibility. In nature, the organic-inorganice composite material nacre features very thin organic interlayers that serve as an ahdesive to hold together single platelets in a "brick and mortar" composite microstructure. This project addresses whether varying the thickness of nacre-like adhesive layers influences the mechanical properties of the composite. Typical standardized tensile tests listed in the American Society for Testing and  Materials (ASTM) will be modified to simulate nacre's structure. Our approach is to linearize the loading path, by performing the double lap shear configuration suggested in ASTM D3528 on a Shimadzu tensile tester. A digital microscope is used to focus on the interactions at the interfaces, while the Scanning Electron Microscope (SEM) focuses on the fibril formation in the adhesive. The adherends we will use are glass, bonded together with varying adhesive thicknesses and placed in the Shimadzu's metal grips for testing. The results display lap shear strengths as a function of lap length with constant lap width. By plotting lap shear versus lap length over adherend thickness (L/t),  we can compare the lap shear performances for the varying thicknesses. If the bond width is held constant it is expectd the bond area decrease with decreasing L/t so shear strength increases as a function of decreasing lap area. The use of transparent glass slides determines if the fracture patterns in bending would spread energy over a larger volume depending on the thickness of the adhesive. The effect of varying the adhesive thickness within the material is discussed as a function of the material's ability to transfer the load over a larger volume more readily during bending, and thereby control the energy dissipation. 

The study of naturally occurring materials for use in every-day applications can result in innovative advancements in current technologies. Nacreous shell structure (nacre) is one such material. This nacre is a composite of ceramic in a tiny, organic, viscoelastic matrix meaning it exhibits time-dependent viscous and elastic behavior. This allows the normally brittle ceramic to be crack tolerant rather than to show high fracture toughness. Other complex composites have been shown to retain much of their strength after cracking, and this means high levels of energy dissipation. Because other structures with many thin organic layers have large damping abilities, it was suspected that nacre would also show such damping, but these damping abilities have not been tested. We hope to gain a better understanding of the damping effects of nacre by looking at tan (δ) through Dynamic Mechanical Analysis (DMA). Tan (δ) is a measure of energy dissipation by damping. A high amount of energy dissipation would have practical applications in creating safer buildings in the case of an earthquake. The viscoelastic matrix that allows for a crack tolerant material could allow for buildings to retain some of their structural integrity while people safely evacuate the building. As viscoelastic components are not typically used in structural ceramic composites, this could provide the basis for a new class of industrial composite materials.

Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of death in the United States. About 50% of people who suffer from COPD die from cardiovascular diseases (CVD). The Metabolic Syndrome (MS), a group of risk factors associated with CVD, is increasingly recognized in COPD. In the general population, fatty liver disease (FL) is a risk factor for MS. The goal of this project was to assess the association between FL and MS in smokers at risk for and with COPD. We also sought to determine the relationship between FL and inflammation biomarkers. We measured the liver and spleen attenuations on CT scans from two large epidemiological studies in smokers. Study A enrolled smokers 45-80 years old in 21 centers across the US. Study B enrolled smokers 45-85 years old in the US and European countries. The liver to spleen attenuation (LSR) was calculated by dividing liver attenuation by spleen attenuation. FL is defined as a LSR ≤1.10 (approx≥30% infiltration of fat). In Study B we used the Spearman Correlation Coefficients to assess the correlation between LSR and inflammatory biomarkers in order to understand a potential mechanism linking FL and MS. In Study A, 18% had FL. FL was significantly associated with diabetes (odds ratio [OR] 2.49 [95% confidence interval [CI] 1.59-3.89]), hypertension (OR 1.52 [1.06-2.17]), and overweight/obesity (OR 2.24 [1.49-3.39]) in adjusted models. Female subjects in Study B, LSR was significantly associated with highly sensitive C-reactive protein (r, -0.41; P<0.021) and fibrinogen (R, -0.40; P<0.020). No such associations were observed in males. In smokers with and without COPD, FL increases the risk for MS. In females, inflammation may be involved in the association between FL and MS.

Patients with Alzheimer’s disease experience progressive loss of memory and thinking skills, gradual declines in the ability to carry out simple tasks and, in severe cases, full blown dementia. The brains of patients with Alzheimer’s accumulate extracellular plaques of a family of beta amyloid peptides (strings of amino acids cleaved from a larger protein called Amyloid Precursor Protein) in multiple regions of the cerebral cortex resulting in losses of synapses and neurons. Given the fact that beta amyloid peptides have been evolutionarily conserved, our group became interested in the potential normative roles of these peptides. Observations by a member of the Martin lab led to the hypothesis that small concentrations of beta amyloid may have a proliferative effect on cells. My project explores this idea with experiments that compare the proliferative effects of various members of the beta amyloid family and dose-response experiments that determine optimal concentrations for proliferative effects. In my experiments, various concentrations of beta amyloid 1-40 (and, as controls, comparable levels of a scrambled beta amyloid peptide 40-1) are added to a standard culture medium along with 10% embryonic serum (serum without detectible levels of beta amyloid peptides) and established required growth factors. The cells’ division rates within those two week periods are determined for individual clones though crystal violet staining. From these initial experiments, we have concluded that cells are indeed able to divide more rapidly in media that has beta amyloid 1-40 present and that further attempts to determine optimal concentrations should focus within the range of 1-10 nM and above 10 nM to the point at which we anticipate evidence of toxicity. Future experiments will probe changes in gene expression resulting from treatment with optimal concentrations of beta amyloid for the enhancement of cell proliferation.