Schedule of Events

Microplastic pollution is a significant environmental concern, particularly in coastal and agricultural regions where human activities contribute to contamination. This study compares microplastic and microfiber pollution between Channel Islands Harbor, a recreational and commercial hub, and the Santa Clara Riverbed, which runs through agricultural land before emptying into the Pacific Ocean. By analyzing sediment samples from both sites, we aim to identify the sources and distribution of microplastic contamination in these contrasting environments. 
Sediment samples were collected at high tide marks from both locations and processed using vacuum filtration and Rose Bengal staining to distinguish synthetic microplastics from organic material. Samples were examined under a Nikon dissecting microscope for quantification, and Fourier Transform Infrared Spectroscopy (FTIR) was used for material identification. 
Preliminary results indicate higher concentrations of microfibers in the harbor, likely due to boating activity, urban runoff, and marine infrastructure, whereas the riverbed samples contained more microplastics, likely originating from agricultural runoff, textiles, and irrigation systems. The findings highlight distinct pollution sources in coastal and inland environments, emphasizing the need for further research on pollution mitigation and regulatory measures.

Single leg squats (SLS) are a common and effective exercise that strengthens lower body musculature and are used in clinical settings to assess movement patterns. SLS are functionally relevant to the unilateral movements that athletes often perform which involve a high risk of knee and hip injuries. The purpose of this study was to examine the effect of load on joint kinematics for each lead leg during a SLS movement. Fourteen injury-free experienced male participants performed three sets of SLS with loads of 0%, 40%, and 80% of their 1RM with each lead leg. The participants’ 1RM for each leg was determined in a previous session held at least 72 hours before testing. Eighteen reflective markers were placed on each subject to collect 3-dimensional kinematic data using eight Vicon motion capture cameras. Nexus software provided joint angle data values (minimum, maximum, range of motion (ROM)) in the frontal and sagittal planes which were averaged over 5 repetitions for the lighter loads and 3 repetitions for the heaviest load.  A repeated measures ANOVA determined the effect of load for each lead leg and joint with post hoc testing determining pairwise differences (p < 0.05). There were significant differences in pelvis, hip, knee, and ankle kinematics for each lead leg based on load. The effect of load varied between lead legs with more differences in the frontal plane than the sagittal plane. There were significant differences in the repetition time and time down during the SLS movement.

Black Lake, one of the “Dune Lakes” located within San Luis Obispo County’s Callender Dunes, is a sedimentary archive reflecting millennia of climate change and anthropogenic activity. The Dune Lake wetlands presently harbor several threatened and endangered species, suggesting long-term persistence of these freshwater aquatic ecosystems. Urban expansion, agricultural groundwater extraction, and drought have recently put these rare ecosystems at risk. Only Black Lake is known to have been perennially wet since the 20th Century. In an effort to disentangle natural and anthropogenic causes of environmental change at the site, two lake sediment cores were collected in collaboration with the U.S. Fish and Wildlife Service, 3.96m and 6.98m respectively. These records span the past 3300 years. Paleoenvironmental proxies indicate dynamic shifts throughout the late Holocene, including a dramatic decline in macroscopic charcoal in the upper 60 centimeters, potentially tied to a decline in native burning after European colonization. Pre-1800 CE fire regimes likely reflect both periods of drought and indigenous Chumash land use practices, suggesting elevated fire activity that plummeted after European settlement. The cores contain notable sand deposits and positive magnetic susceptibility excursions in the top two meters of both cores, reflecting high-energy depositional events, presumably aeolian in origin. The presence of high organic content peat and the persistence of Cirsium loncholepis (La Graciosa thistle) at the site indicate that Black Lake has likely remained a wetland throughout the Holocene.

Elliptic curve cryptography allows messages to be encrypted through an algorithm that takes advantage of a special property of ellitpic curves. It is one of the most popular encryption methods and is used by companies such as Apple, Facebook, and Microsoft. With our personal and national privacy relying on it, it is important to understand the mathematics behind this encryption method. This project gives an undergraduate level explanation of elliptic curves over a finite field, the dotting function, algorithms to count points over a finite field, and discussion around the implementation of the encryption method. This project is meant to act as an information compilation, with some application aspects, with the goal of simplifying this important encryption method for general understanding.

Virulent bacteria rely on iron for survival. One way they compete for and acquire iron is by synthesizing siderophores, which are iron chelators. There are two main pathways to synthesize siderophores: NRPS and NIS. The siderophore desferroxiamine E, is synthesized through the NIS synthesis pathway; the final enzyme of this pathway is NIS synthetase DesD.  DesD is a model enzyme for the NIS Synthetases, which are increasingly associated with virulence in bacteria, unique in structure and function, and therefore an excellent drug target. The Hoffmann lab is interested in characterizing the NIS mechanism. We predict a two proton shift in the reaction mechanism of DesD and will test the hypothesis via a pH profile, where we analyze the difference in kinetic turnover in altered pH environments. Our kinetics protocol is ITC-based and well-established. The goal of this specific project is a full pH profile of DesD’s kinetics, which supports the short term objective of characterizing biochemistry of the enzyme. This and other projects from the lab will contribute to the long term objective of this research, which is to establish a new class of antibiotics that target multidrug resistant bacteria. 
 
 
 

RNA thermometers are non coding structures located in the 5' untranslated regions (5’-UTRs) of messenger RNAs (mRNAs), responding to temperature fluctuations by undergoing conformational changes. A well-known RNA thermometer is the FourU motif, composed by two non-canonical G•U wobble base pairs. These unstable base pairs contribute to the melting of a terminal hairpin structure under heat stress, enabling downstream gene expression. To support the discovery and validation of RNA thermometers, we developed Robo-Therm, a pipeline that integrates computational and experimental methods. Through this platform, we identified two novel FourU RNA thermometers:one located upstream of the RNA polymerase sigma 70 gene, responsible for directing bacteria to specific promoter regions to begin transcription, and another in the 5′ untranslated region (UTR) of the tetracycline resistance gene (tetR), which helps bacteria survive antibiotics. Robo-Therm can be used to identify RNA thermometers in diverse bacterial genomes and test their temperature-dependent activity at 25°C, 37°C, and 42°C using a reporter plasmid containing beta-galactosidase and techniques including PCR, HiFi assembly and cloning.
Expanding on this approach, we aim to investigate whether the 5’-UTR of ComFA, a gene for natural transformation in Gram-positive bacteria, also exhibits temperature-dependent regulation. ComFA facilitates the uptake of single-stranded DNA (ssDNA) for genomic integration. We are currently assessing the effect of different temperatures on potential RNA thermometer activity in Bacillus subtilis, aiming to better understand how these structures contribute to bacterial adaptation and gene regulation in response to environmental stress.

We analyze the rotation curves of spiral galaxies to quantify their dark matter component and better understand the impact it has on spiral galaxy dynamics. Previous observations show that the stellar mass alone cannot account for the gravitational effects seen in rotation curves, indicating the presence of large dark matter halos surrounding these galaxies. We calculate rotational velocities from spectra observed during the first year and survey validation period of the Dark Energy Spectroscopic Instrument (DESI) Peculiar Velocity Survey, and model the rotation curves of those spiral galaxies that pass visual inspection. Parameterizing the rotation curves allows us to estimate the total mass of the galaxies within R26 (the radius of the 26 mag/arcsec2 isophote). We find a strong correlation between this total mass and the galaxy’s luminosity, which is to be expected from the Tully-Fisher relation and confirms the validity of our total mass calculations. Additionally, the relationship between total mass and stellar mass, as well as the ratios of gas to stellar mass and dark matter to stellar mass, provide insights into the distribution of dark matter within spiral galaxies, allowing us to better constrain the properties of dark matter.