Just Keep Swimming: A Study of if Artemia salina's Activity Can Measure Water Toxicity

Overview

In Okinawa, Japan, the American Military Air Stations will use JET-X 2.75, to extinguish fires on the airstrip. The runoff of this chemical, Perfluorinated Compounds (PFCs), has been found in concentrations exceeding the United States Environmental Protection Agency (USEPA)'s advisory level of toxicity for safe drinking water. This lethal chemical is known to cause cancer, neurological, and reproductive disorders. A common way to detect the presence of PFC in water is chromatography, which is very expensive. However, Artemia salina (A. salina), small invertebrates which are used in lethality bioassays to measure cytotoxicity, could be a less expensive substitution. Gasoline and Scotchgard were over the counter chemicals used to simulate PFCs. A. salina were grown to the average size of 10 mm and then exposed to different concentrations of Scotchgard and gasoline. The hypothesis was that the difference in swimming speeds of A. salina exposed to safe drinking water versus highly toxic water containing gasoline or Scotchgard are statistically significant. There was a statistically significant difference in the swimming speeds of A. salina when exposed to gasoline. However, there was no statistical significance found for Scotchgard. The PFC found in Scotchgard is less than 3% which could have impacted the outcome of this experiment. Therefore, the swimming speed of A. salina may be an effective way to measure high toxicity in water however more testing is needed to find the range of toxicity measurable by A. salina. Applying a Novel Hot-Casting Technique to Increase Perovskite Solar Cell Grain Size, Stability, & Efficiency in Photovoltaic Application Jasmine Li Fairview High School Boulder, CO Mentor Miriam Rafailovich Stony Brook University Stony Brook, NY Solar cells mitigate the severe effects of climate change by directly converting light into electricity. In particular, perovskite solar cells (PSCs) have recently demonstrated fast-rising efficiency. However, the main limitation of PSCs is the issue of instability. The instability arises from formation of small-sized grains with a large density of grain boundaries (GB) and defects. These defects largely result from the conventional post-annealing method used in perovskite layer preparation. To promote stability and efficiency, I utilized a new technique called hot-casting in which the perovskite precursor solution and substrate are preheated before spin-casting. Annealing and spin-casting at the same time provides an ideal environment for crystal grain growth. In scanning electron microscope images, hot-casted PSCs produced an average grain size of 11.40 μm, nearly 60x greater in size than the average grain size of 194 nm obtained conventionally. Atomic force microscopy images showed that hot-casted perovskite demonstrated such vigorous crystal growth that neighboring grains collided at the edges, forming a uniform, fully covered, and highly crystalline film; in contrast, conventional perovskite produced a fine-grained film with a large density of GB. X-ray diffraction (XRD) confirmed that hot-casting didn’t lead to any lead iodide impurities and ultimately enhanced the crystallinity. Most notably, PSC performance tests demonstrated an efficiency increase of ≈38% when using hot-casting, from 12.2% prepared conventionally to 16.8% prepared via hot-casting. Thus, hot-casting has demonstrated to be an effective method to increase PSC grain size, stability, and efficiency for wide-scale commercial photovoltaic application. Identifying Key Pathways/Mechanisms for the Generation of Pancreatic Beta Cells by Trans-differentiation of Acinar Cells Abby Liu* Hamilton High School Chandler, AZ Teacher Ms. Raxha Bhagdev Hamilton High School Insulin is produced in the 𝛽 cells of the pancreas. Individuals with diabetes either lack insulin (T1D) or have a reduced insulin secretion or action (T2D). Therefore, preservation of 𝛽 cell mass is crucial for treatment. Pancreatic 𝛽 cell mass is maintained by several mechanisms, which include self-replication, trans-differentiation from stem cells, and trans-differentiation from non-𝛽 cells, for example, pancreatic acinar cells. Since acinar cells are by- products of islet transplantation, their utilization will be an interesting approach to supplement the current limited availability of islet cells. Trans-differentiation, however, requires extensive knowledge about the key regulators that control 𝛽 cell development/growth, and maintain 𝛽 cell function. Furthermore, to improve the overall efficiency of the generation of 𝛽 cells from acinar cells, it is imperative to understand the underlying mechanism for such trans-differentiation. Here, we investigated transcription factors critical for 𝛽 cell generation, and determined the combination of transcription factors that resulted in a more efficient generation of 𝛽 cells from acinar cells. Results show that when compared to basal, Rbpjl and Ptf1a knockdown in 266-6 mouse acinar cells increased the overall expression of essential 𝛽 cell genes. Additional overexpression of Ngn3, Mafb, and Nkx6.1 further increased the expression of essential 𝛽 cell genes including insulin. This is the first study, to our knowledge, to show that inhibiting Rbpjl and Ptf1a and therefore disrupting acinar cell characteristics may aid in the conversion of acinar cells to pancreatic 𝛽 cells.

Competition history

• JSHS 2020 Category not listed

Resources

• National JSHS abstract book ↗

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