UC Riverside Undergraduate Research Journal

The knee joint faces daily stresses that cause its overall health to degrade and pathologies to develop. I hypothesized that increased stress on the knee joint and imbalance in thigh musculature would positively correlate with increased acoustic emissions from the knee joint, a biomarker of inflammation in the joint. We tested this hypothesis by selecting a cohort of healthy, moderately active individuals aged 18-32 across a range of BMIs. We collected baseline knee acoustic measurements and measured quadricep and hamstring flexibility, hamstring and quadricep maximum voluntary isometric contraction, and heel strike angle during self-selected walking gait. Heel strike angle does not correlate with increased acoustic emissions from the knee, but BMI negatively correlates with the hamstrings:quadriceps strength ratio. Furthermore, left hamstring flexibility positively correlates with left heel strike angle. Finally, we found that right quadricep flexibility had a positive correlation with right heel strike angle. Since the hamstrings:quadriceps strength ratio is an important biomarker for knee health, this finding may indicate evidence of progressing knee pathology in individuals with higher BMI. Changes in gait associated with muscle rigidity indicate that differential levels of upper leg muscle flexibility may translate to changes in the mechanics of everyday movements, such as walking.

Procrastination is a widespread problem among students, yet feasible solutions have remained elusive. Recognizing the detrimental impact of procrastination on students’ potential, this study aims to investigate the underlying factors contributing to this problem. Specifically, this study explores the associations between academic identity, self-esteem, and procrastination in both male and female participants. Previous research suggests a negative relationship between self-esteem and procrastination. There has been substantially less research examining the relationship between academic identity types (i.e., achieved, foreclosed, moratorium, and diffused academic identity) and procrastination. The current study surveyed 244 college students about their personality habits, academic identity, and self-esteem. It was hypothesized that self-esteem would moderate the relationship between achieved academic identity and procrastination. Regression analyses support this hypothesis, indicating that college students who have a well-developed sense of achieved academic identity are less likely to procrastinate in academic settings, especially for students high in self-esteem. Additionally, results suggest students who have not made a commitment to academic goals and values, are more likely to procrastinate. Theoretical implications for studying academic identity and procrastination will be discussed, along with intervention recommendations for college students.

 The dynamics of epithelial cells during wound healing exhibit significant complexity, notably in their size-dependent behavior. This work aims to depict a fundamental mechanism underlying this size dependence in cellular dynamics by developing a computational model. Our research question investigates how the physical size of epithelial cells influences their motility and behavior patterns, specifically during the epithelial-to-mesenchymal transition critical for wound healing. Thus, we propose a model where the key mechanism involves a field of spatially coupled forces acting on the cell membrane, driven by the dynamics of actin monomers. These monomers, randomly distributed within the cell, become focal points for membrane protrusions, thus influencing cell behavior. Our model succinctly captures the essence of size-dependent cellular dynamics without resorting to changes in gene expression patterns, offering new insights into the variations in cell behavior. Through this computational framework, we demonstrate that the diversity in cellular responses during wound healing can be fundamentally attributed to differences in cell size. This insight contributes to a deeper understanding of the behavioral plasticity of epithelial cells in critical physiological processes like wound closure. 

Influenza is one of the most prevalent viruses that has plagued millions worldwide. Every year health organizations encourage the public to get their flu vaccines to combat the flu season. Although the flu vaccines and medicines are widely available, it is estimated that flu viruses still cause 20,000-50,000 deaths every year. The two most common influenza virus strains are influenza A and B viruses, or IAV and IBV, respectively. It has been discovered that drug resistance develops very soon after a new drug is launched. It is highly demanded that anti-flu virus drugs with novel mechanisms be developed. Our lab has discovered that SUMOylation, a post-translational modification, is essential to the viral IAV and IBV life cycle. In this study, we have screened all the E3 ligases in the human genome to discover the SUMO E3 ligase responsible for the essential SUMOylation of IAV M1 protein using our Quantitative Fluorescence Energy Transfer(qFRET). We first determined the FRET spectrum of all E3 ligases with M1 protein and then quantified the FRET signals to provide a first-line examination of interactions. We then determined the E3-M1 interaction affinities, KD, to ensure the real interactions. We found the E3 ligase PIAS1 has the highest affinity to M1 among other E3s. By understanding the interaction affinity between IAV M1 protein with SUMOylation E3 ligase, we hope to block the interaction between the PIAS1-M1 for novel anti-flu medicine development. 

Pacing is a critical mechanism for sustaining performance. When making decisions, people must consider the demands of a task to pace themselves accordingly. Compared to sports literature, this project looks at pacing and how it manifests in an everyday work environment - an area of research that is surprisingly little studied. The team sought to study pacing, by comparing performance over successively longer distances, like sprints compared to marathons. In two preliminary experiments, undergraduate students pressed the enter key some varying number of times, N = [8 16 32 64]. Additionally, students were told to exceed N just as runners run through the finish line of a race. The main question was if participants would tap slower when N was large compared to when N was small, just like runners. Surprisingly, participants did not change their performance based on N and participants slowed dramatically as they approached N, despite being instructed not to. Our main method of measurement was the mean interresponse interval (IRI) which is the average elapsed time between consecutive taps. We changed the count feedback between separate experiments and no change has extinguished the slowing effect. Results from two experiments show premature slowing suggesting that as people approach the end of a task, they slow their performance. This new phenomenon has implications for everyone who does multiple tasks in a day. Future work will explore whether changing the tap rate or removing the IRI feedback will affect the premature slowing phenomenon. 

While visual attention has been studied extensively, haptic attention has remained relatively unexplored. Haptic attention is an integral facet of everyday life, often arising in everyday activities like feeling for a pencil in a backpack or searching for keys in one’s pockets. We sought to understand how proprioception and features in objects contribute to the efficiency of bimanual haptic search in an unrestrained environment. The haptic task required participants to search for a target item among a set of distractor items without the use of vision, either in a single container, using hands together, or in separate containers with hands apart. We investigated whether the use of two hands enhanced or impeded search efficiency. The items to be felt were cylinders of varying length and volume. We found that bimanual search in one container was not appreciably different from bimanual search in two containers. We also found that there was an additive effect of diameter discrimination and length discrimination on search efficiency.

In biological studies in vitro and in vivo, techniques involving Förster resonance energy transfer (FRET) and FRET quantification use the interaction of CyPet-SUMO1 and its E2 ligase, YPet-Ubc9, to determine the dissociation constant (KD). Dipole-dipole resonance interactions, where energy transfers from an excited donor to an acceptor chromophore, allow the detection of molecular interactions to elucidate protein interactions in many regulatory cascades spanning signal transduction, medical diagnostics, and optical imaging. This study was aimed to explore how protein-protein interactions are affected by the crowded environment typically found within cells using FRET signals. An in vitro assay using a 96-well plate was conducted using varying concentrations of bovine serum albumin (BSA) to simulate crowded conditions and determine their effect on KD values. FRET measurements were conducted in a solution phase to mimic the protein interaction affinity in living cells. In contrast, other KD measurement methods such as radio-labeled ligand binding assay, surface plasmon resonance (SPR), or isothermal titration calorimetry (ITC) require extensive preparation or orientation on solid surfaces, making them less representative for such assessments. Emission wavelengths from CyPet-SUMO1 (414 nm to 475 nm) and YPet-Ubc9 (475 nm to 530 nm) were obtained to determine fluorescence signals along with KD. A comparison between protein interactions in crowded and uncrowded settings was made with varying KD value results. This investigation provides insights into protein interactions and cellular crowding, with potential implications for pharmaceuticals, bioseparations processes, and drug discovery targeting protein-protein interactions.

Despite increased institutional awareness toward diversity, equity, and inclusion on college campuses, LGBTQ+ students–and especially LGBTQ+ students of color–continue to experience disproportionate mental and behavioral health burdens and food insecurity compared to their cisgender and heterosexual peers. To address this issue, QTPOC (Queer and Trans People of Color) is a student organization that supports students at the intersection of oppression based on race, gender, and/or sexuality on campus. This study aims to evaluate how well our organization serves QTPoC students and how student organizations can better serve QTPoC students in general. Specifically, we study the impact our programming model–which integrates educational elements with incentives to attend events including food and crafts–has on QTPoC's well-being and knowledge of mental health resources on campus in order to both understand the factors contributing to mental health disparities and to evaluate strategies aimed to remedy those disparities. We recruited QTPoC students to complete pre- and post-event surveys to assess attendance, motivation, well-being, and awareness of campus resources regarding both food insecurity and sexual and gender health. We find increases in knowledge and well-being among QTPoC students who attended QTPOC events. We also found that offering hot food significantly contributed to positive experiences, fostered community building, and alleviated concerns regarding food insecurity. We conclude that our programming model effectively combats mental health disparities and food insecurity among QTPoC students. Student-serving organizations looking to address disparities among marginalized students should consider adopting our programming model.