Understanding the spread of COVID-19 is important to all aspects of our life in this pandemic. The more we know about how COVID is transferred from one person to another the more quickly we can come up with counter-measures and protective practices. One of the key ways we know that the disease spreads is on water droplets expelled as we talk and breathe. The spread of these droplets should match our understanding of the spread of an aerosol, which we here model using Computational Fluid Dynamics. We use the popular CFD platform OpenFOAM to simulate the spread of aerosols in a 3D model of our physics lab room. In conjunction with the computer simulation, we construct a small scale physical model of the lab room, and with the help of a high speed camera and fluorescent dye, we track the actual spread of water droplets expelled into the enclosed space. These comparative experiments help us to understand where the simulated model needs refinement and provide valuable insights into how we can combat the spread of this pandemic.

Every winter, snowstorms impact millions of people throughout the Northeast United States (U.S.). The origin of most east coast snowfalls, mid-latitude cyclones, vary significantly in strength, size, and temperature, leading to a broad range in snowfall amounts. With a better understanding of the microphysical processes of East Coast snowstorms, remote measurement and weather model accuracy will significantly improve. That is precisely the goal of the NASA-funded project: Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS). The observational strategy for IMPACTS includes one airplane equipped with multi-frequency radars flying above the cyclone and remotely observing clouds and precipitation while a second airplane flies within these clouds and collects direct information about the shapes, sizes, and concentrations of particles (e.g. microphysics). This particular study investigates a mid-latitude cyclone that occurred during IMPACTS and affected the Northeast U.S. on January 25, 2020. This storm featured periods of convection embedded in broad regions of storm clouds and small-scale convection originating near the top of these clouds in what is termed ‘generating cells.’ This study will relate radar observations from the aircraft above the clouds to the observations of particles from the aircraft that flew within the clouds. The ultimate goal is to document the microphysical processes both within and outside the convective regions and the generating cells and how these processes contribute to enhanced snowfall at the surface. We hypothesize that convection leads to a large variance in snowfall totals. Understanding the microphysical processes within convection will help improve snowfall forecasts at regional and local scales, and our observations and analysis will help us understand these processes in further detail.

Lahars are mudflows that originate from volcanoes and commonly flow down river channels. They have the potential to deposit large amounts of sediment, reducing the capacity of the channel to carry water and possibly resulting in worsened seasonal flooding. Mt. Rainier has a history of lahars in most of the major rivers that originate from it, except for the Carbon River, which has little geologic evidence of lahars. In contrast, the Puyallup River contains sediments from the Electron Mudflow that occurred 500 years ago. Because the Carbon and Puyallup Rivers have a similar orientation and source, they make ideal candidates to compare flooding and sedimentation data to determine the effect of lahar sedimentation on flooding. If lahar sedimentation played a major role in flooding, we would expect the Puyallup River with its lahar deposits to have a greater frequency of flooding when compared to the Carbon. However, comparison of annual peak flow data from the years 1930 to 2019 suggests that this is not the case. For this study, it is assumed that the years with peak stream flows that exceeded a designated flood stage stream flow, given by the National Water Information System, experienced flooding. The Puyallup and Carbon Rivers had a similar number of flood events that exceeded the flood stage stream flow, however the Carbon’s flood events were generally much greater than the flood stage value when compared to the Puyallup. Overall, there is not a significant enough difference in flooding between the two rivers to suggest that the Electron Mudflow deposits have an effect on flooding. The Electron Mudflow occurred approximately 500 years ago, so it is possible the lahar sediments in the Puyallup River have been sufficiently carried downstream and both rivers have returned to a similar balance of sediment transport and water flow.

Trisomy 21 (T21), also known as Down syndrome, is a disorder in which an individual has a third copy of the 21st chromosome. This genetic disorder causes mental and physical, and developmental deficits depending on the individual. In our project, we are using retinal tissue to study the differences in morphology, location, and number of immune cells in fetal tissue samples with trisomy 21 versus those without. It has been observed that increased cytokine (signaling molecule) levels in mice with trisomy 21 interfere with certain signaling in the hippocampus of the brain. Another trend is the spine density being lower in trisomy 21 mice, which ultimately decreases neuron activity in the hippocampus as well. Microglia, which are the immune cells of the brain and eyes, behave differently and reside in different areas pertaining to the retina specifically. Overall, the cognitive deficits in trisomy 21 mice could be due to the microglial dysregulation that has been previously observed. More importantly, we want to focus on the idea that hyperactive microglia can cause alterations in the function of certain neuronal circuits, leading to the observed effects of trisomy 21. As a preliminary experiment, we stained and imaged whole retinal spheres from human fetal retinas and found the number of microglia yielded no significant difference between T21 samples and control samples. However, we found that the T21 microglia looked much larger and resided in different areas of the retinal tissue than the controls. We will observe these differences further through staining and identifying the activation level of microglia by morphology in the retinas of T21 versus control fetal tissue.

Alzheimer’s disease, the most common human neurodegenerative disorder, is characterized by hyperphosphorylation of the protein tau, leading to the protein’s aggregation and the formation of neurofibrillary tangles. The subsequent neurodegenerative consequences of these tangles may influence the biological response and sensitivity to neurological stressors, such as a traumatic brain injury (TBI). A TBI usually results from a strong blow to the head that leads to damaged brain cells and neurodegeneration. In the Promislow Lab, we are currently examining how neuronal tau affects the mortality response to a TBI-like trauma in the fruit fly, Drosophila melanogaster. Using the UAS-GAL4 gene expression system, we are able to induce the expression of the tau gene in fly neurons from eclosion. From both an experimental fly genotype (tau expression) and a control fly genotype (no tau expression), we are currently sampling flies at various time points during their lifespan and administering a TBI-like trauma on the flies using a high-impact trauma device. To quantify the impact of tau on the flies’ response to the TBI-like trauma, we are recording the percentage of flies dead 24 hours later (24 hour mortality index). We hypothesized that inflicting a TBI-like trauma would lead to a significantly increased 24-hour mortality index in the experimental genotype compared to the control genotype due to increased sensitivity in the former. Thus far, we have observed significantly increased mortality in response to a TBI-like trauma in the control genotype compared to the experimental genotype. The decreased mortality in the experimental genotype suggests a novel positive role of tau in the response to a TBI, which holds significant implications for targeting clinical TBI treatments and therapies. Further analysis and follow-up experiments will provide useful insight into understanding the mechanisms of tau’s role and the pathways of both Alzheimer’s and TBIs.