Schedule of Events

Our research examines several taxa of benthic foraminifera (e.g., Trochammina inflata, Siphotrochammina lobata, Entzia macrescens, Miliammina fusca) from six surface samples retrieved in March 2025 from Carpinteria Salt Marsh in Carpinteria, California. At each sampling location we collected water quality parameters (i.e., temperature, dissolved oxygen, specific conductivity, salinity, pH, and turbidity) and noted the proximity to sources of human impact, namely the train tracks that run behind the marsh. Foraminiferal numbers (foraminifera/g) have a positive relationship with dissolved oxygen levels and a negative correlation to salinity levels.There is also a negative relationship between grain size and foraminifera/g. Preliminary results show that there are seven different taxa in the marsh channel, with high numbers of Trochammina inflata and Siphotrochammina lobata. Both of these species thrive in low salinity levels (Walker et al., 2020). By studying the composition of benthic foraminiferal assemblages, analyzing water quality at the sampling sites, and evaluating the sources of human impact, we are able to gain a better understanding of how human impact and changes in water quality affect foraminifera in Carpinteria Salt Marsh. 

This paper investigates whether hitting with two outs is more impactful than hitting with no outs, using play-by-play data from all 162 games of the Los Angeles Dodgers' 2024 regular season. Situational hitting is a key element of offensive baseball strategy, yet despite its strategic importance, the relationship between hit values (single, double, triple, or home run) and the number of outs recorded remains unclear. To examine this relationship, two approaches are applied: linear regression and a Markov chain simulation. The linear regression models compare how traditional offensive statistics, specifically batting average and on-base percentage, influence run production under each out state. The Markov chain simulation models offensive inning progression using transition matrices built from observed plate appearance probabilities, allowing for the computation of run expectancy across all base and out states. To evaluate the true impact of each out state, offensive probabilities were adjusted by each out state to simulate improved hitting in specific situations. Together, these methods provide a framework for understanding when hits matter most and how teams can maximize offensive production throughout an inning.

Nonribosomal peptide synthetase-independent siderophore (NIS) synthetases are enzymes found in some bacteria that produce hydroxamate siderophores (Challis et al., 2005). Siderophores help pathogenic bacteria compete in iron-deficient environments by increasing the solubility of iron (Fe+3) for bacterial uptake and survival (Neilands, 1993). NIS siderophores are important virulence factors because they are not easily identified by the human immune system (Oves-Costales et. al, 2009), and therefore the NIS Synthetases that make them are compelling drug targets. The chemical mechanism of NIS synthetases is not well understood, however their adenylate intermediate and novel protein fold have been recently proposed (Schmelz & Naismith, 2009). Understanding the mechanism for NIS synthetases will aid future structure-based drug design, which is the long-term goal of the Hoffmann Lab. 
This research project focuses on the acid/base proton transfer proposed in our two-step adenylate forming hypothesis using the model enzyme DesD from Streptomyces coelicolor. We propose that E467 acts as a general acid and general base in the second step of the mechanism and have shown that only half of the bond forming events occur kinetically. The next step of this project will test the hypothesis of a two-proton dependence in siderophore biosynthesis using a pH profile: our established kinetics experiments at systematically different pH levels to analyze kcat’s dependence on pH. A figure graphing this relationship will be constructed, and its slope will be analyzed to provide evidence for our hypothesis. We will present our preliminary data.

Microplastic pollution along California is a growing ecological concern for marine and human health. Synthetic microfibers, which are released from textiles during laundering cycles, comprise an overwhelming 70% of microplastic pollutants. With an estimated 100,000 per garment and 9,000,000 fibers shed per laundering cycle, microfibers contribute about two million tonnes of marine debris annually. While few current mitigation strategies exist, including textile engineering approaches, and waste treatment, little is known about the geographical distribution of these pollutants into marine environments, specifically sediments. The purpose of this study is to compare sediment contamination between two geographically different locations; Leo Carrillo State Beach in Malibu, an open-coastal beach, and Avalon Harbor, an enclosed harbor on Catalina Island, 22 miles off shore from Los Angeles, California. Given the pathways of the North Pacific Current, California Current and the proximity to runoff locations, it was predicted that there would be more microfibers in the Malibu location as compared with the Island Harbor. Sediment samples were randomly collected from areas between the subaerial beach and the breaking waves in the intertidal zone. Samples were processed using a 1:2 sediment-to-seawater ratio, then agitated to separate microfibers from sediment. A Büchner funnel filtration system was used to capture fibers on filterpaper, then quantified using light microscopy. Our findings suggest higher microfibers abundance at Leo Carrillo State Beach compared to Avalon Harbor. These findings emphasize the necessity to understand the transport, distribution, and ecological impacts of microplastics and fibers, in order to construct an effective mitigation plan.

Microplastic pollution along California is a growing ecological concern for marine and human health. Synthetic microfibers, which are released from textiles during laundering cycles, comprise an overwhelming 70% of microplastic pollutants. With an estimated 100,000 per garment and 9,000,000 fibers shed per laundering cycle, microfibers contribute about two million tonnes of marine debris annually. While few current mitigation strategies exist, including textile engineering approaches, and waste treatment, little is known about the geographical distribution of these pollutants into marine environments, specifically sediments. The purpose of this study is to compare sediment contamination between two geographically different locations; Leo Carrillo State Beach in Malibu, an open-coastal beach, and Avalon Harbor, an enclosed harbor on Catalina Island, 22 miles off shore from Los Angeles, California. Given the pathways of the North Pacific Current, California Current and the proximity to runoff locations, it was predicted that there would be more microfibers in the Malibu location as compared with the Island Harbor. Sediment samples were randomly collected from areas between the subaerial beach and the breaking waves in the intertidal zone. Samples were processed using a 1:2 sediment-to-seawater ratio, then agitated to separate microfibers from sediment. A Büchner funnel filtration system was used to capture fibers on filterpaper, then quantified using light microscopy. Our findings suggest higher microfibers abundance at Leo Carrillo State Beach compared to Avalon Harbor. These findings emphasize the necessity to understand the transport, distribution, and ecological impacts of microplastics and fibers, in order to construct an effective mitigation plan.

Collision sports athletes perform repetitive tasks that place high loads on joints including the hip,knee, and ankle. However, there is limited information on how athletes who participate indifferent collision sports vary biomechanically. Thus, the purpose of this study was to comparelower-extremity strength and range of motion (ROM) measures between rugby and Americanfootball athletes. Thirty collision sport athletes (15 rugby athletes and 15 American footballathletes) completed a single laboratory session that included body composition assessment andlower-extremity strength testing using an isokinetic dynamometer. Independent t-tests andMANOVA were used to assess differences between rugby and American football athletes ondependent variables including joint ROM (hip, knee, ankle), peak torque at angular velocities of60, 120, and 180 degrees per second (deg/s), and strength ratios (e.g., hamstring/quadriceps).Effect sizes (Cohen’s d) were calculated for all variables analyzed. It was expected that therewould be significant differences between rugby and American football athletes on most outcomemeasures due to physical demands unique to each sport. Results from this study may revealsport-specific neuromuscular and flexibility characteristics of rugby and American footballathletes. This information could potentially be used to modify strength and conditioning, injuryprevention, and rehab protocols for each population. Additionally, as this is a pilot study, resultswill provide effect size estimates and information on study feasibility for future research.Ultimately, developing a better understanding of sport-specific biomechanics may allow athletesto perform better and decrease their risk of injury both now and in the future.

Topological insulators (TIs) are of great scientific interest due to their insulating nature inside the material partnered with conducting surface states. Bi2Se3 is a TI of particular interest because of its large bulk band gap. Bi2Se3 consists of a repeating quintuple-layer of Se-Bi-Se-Bi-Se and a rhombohedral unit cell. A Bi2Se3 thin film was grown using molecular beam epitaxy (MBE) on a substrate consisting of a Si/SiO2 wafer and a bridge of hexagonal boron nitride (hBN), graphite, and gold. We hope to measure the confined surface states of Bi2Se3 using scanning tunneling microscopy (STM). Both the graphite and hBN were used in the form of flakes and were attained via mechanical exfoliation. The gold was deposited onto the stack of hBN and graphite by means of thermal evaporation. The Bi2Se3 growth occurs in multiple phases, starting with the growth of three quintuple-layers of Bi2Se3 at 140 0C, followed by the growth of nine quintuple-layers of Bi2Se3 at 275 0C, and finished with a final layer of an Se cap at 22 0C. X-ray diffraction(XRD) was used to confirm successful thin film crystal growth on our sample. STM will be used in the future to create confined surface states (quantum dots) to study their properties, including quantum scars, as previously observed on graphene. As STM is a surface-sensitive process, we use our Se cap to protect the Bi2Se3 from oxidization, which would hinder the performance of STM.
This work was supported by the UCSC REU program through the National Science Foundation (Grant # 2349305).