Cannabidiol (CBD) has been found to have anxiolytic effects on behavior when injected (Blessing et al, 2015). In Experiment 1, we investigated whether we could replicate these findings in rats using acute voluntary oral consumption of non-pharmaceutical grade CBD oil at 60mg/kg in Long-Evans rats, with a control group consuming coconut oil (COC). A test was given two hours after consumption to observe any anxiolytic effect of CBD using an elevated plus maze. It was hypothesized that CBD rats would spend more time in the open arms of the elevated plus maze than the control group; however, results revealed that there was no difference between groups. Experiment 2 utilized Fischer rats as subjects to observe the difference in anxiolytic behaviors of TgF344-AD and wild-type (WT) rats and determine if our previous test apparatus was a sufficient measure of anxiety. Previous research has found that AD rats spent less time in the open arms of an elevated plus maze than WT counterparts (Pentkowski et al., 2018). There was no significant difference between the WT and AD rats; however, there was a significant difference between the Fischer rats (WT and AD) and Long-Evans rats (CBD and COC) with the Long-Evans rats spending more time in the open arms than the Fischer rats. Results will be discussed regarding possible factors for finding similar behavior across rats.

Development of the Opioid-Treatment Linkage Model Resource Guide to Strengthen Parole Officers’ Role in Promoting Linkage to Community Services for Individuals Involved in the Justice System

Brooke Preston, Jennifer Becan, PhD, Jennifer Lux, PhD, Chelsea Wood, MPH, Amanda L. Wiese, MS, Kevin Knight, PhD

As funded by the National Institute on Drug Abuse, the Justice Community Opioid Innovation Network (JCOIN) seeks to improve health outcomes for individuals who are at risk for using opioids upon release from correctional facilities. Specifically, JCOIN aims to increase linkage and receipt of community substance use and medication for opioid use disorder (MOUD) treatment within 18 communities across Texas, New Mexico, and Illinois. This system-level initiative will leverage and facilitate cooperation between community corrections staff and community-based treatment providers by providing training on innovative and best practices and service provider lists. Specifically, the Opioid-Treatment Linkage Model (O-TLM) Resource Guide is being designed to help provide parole officers knowledge of the Behavioral Health Services Cascade, which outlines the process of screening, assessment, and referral to health providers, and the treatment that clients undergo. The O-TLM Resource Guide includes information on evidence-based practices and resources that will aid parole officers in more effectively guiding their clients through each step of the services cascade. Additionally, local community provider lists and maps are being created to increase parole officers’ awareness of screening, assessment, and treatment facilities within their community. The list includes a comprehensive catalogue of providers, the services they offer, and their contact information. These guides will hopefully make it easier for parole officers to more actively link clients to community substance use and MOUD services that match the specific client needs.

Past research has shown that merely thinking about an attitude object can result in self-generated attitude polarization (Tesser, 1978). The current study examined the effects of a specific type of thought—extrapolating traits about proponents and opponents of a social issue—on participants’ post-manipulation attitudes. Participants completed an online survey in which they either extrapolated traits about people who support or oppose legalized abortions, or listed synonyms of experimenter-provided personality traits. Participants who extrapolated reported more positive attitudes towards those who agreed and more negative attitudes toward those who disagreed with the participant’s position on abortion than participants who wrote synonyms. Additionally, extremity of extrapolated traits predicted more positive (negative) post-manipulation attitudes towards those who agreed (disagreed) with the participant’s position on abortion. Our findings extended past research on mere thought by offering new insights into a specific thought strategy that can lead to attitude polarization.

Historically women and minorities have been underrepresented in the STEM field. What about individuals who identify as minority women? Their representation in the STEM field is even less than that of White women or minority men. How do we change this phenomenon and increase diversity in the STEM field? This is the question many leaders face every day when trying to increase diversity in their STEM oriented companies, college programs, and departments. Previous research has shown that enrichment programs that help “bridge the gap” between the majority and minority in the STEM field can be beneficial to minority individuals' pursuing a career in this area. (Brown et al., 2020). One aspect that contributes to the pursuance and retention of minority individuals in the STEM field is mentorship. The goal of this study is to evaluate the impact of mentorship on female minority high school students that wish to pursue a career in the STEM field. This topic is important to examine because it can help contribute to data on how to diversify the STEM field by targeting students in high school who wish to pursue STEM degrees in college. The mentorship program in this study helps prepare students to pursue STEM degrees in college by pairing them with a mentor who is currently a minority female in college pursuing a STEM degree and addressing topics such as college applications, resume building, mental health, time management, and navigating STEM classes in college. A series of pre-, during-, and post- surveys were administered via Qualtrics during the mentor program in the 2021/2022 academic school year. The surveys assessed participants' attitudes and feelings toward college, their knowledge and understanding of essential things needed to complete a college application, and if they were able to foster a meaningful relationship with their mentor.

The purpose of the present study was to extend previous studies in our lab that evaluated the stability of classes of stimuli that were learned through Equivalence-based instruction (EBI) and Complete Instruction (CI) procedures. Sixty undergraduate students received training to establish three stimulus classes with four members in each class. The students were randomly assigned to two groups: EBI – in which they received training for some of the relations – and CI – that targeted all possible relations between the members of each class. After undergoing training and equivalence test (Phase 1), participants received contingency reorganization training (Phase 2). In the reorganization phase, new relations between stimuli were established as correct. Stability was evaluated in an immediate contingency-reversal post-test. Overall, there was no statistical difference between EBI and CI groups. Participants made more errors in trials that tested derived changed relations than in trials that tested derived unchanged relations between stimuli.

Examining Parental Alcohol Use, Gender, and Peer Relationships as Predictors of Substance Use Severity
Vinisha Inaganti, Brooke Preston, Kha Hoai Bao Vu, Addison Williams

In the United States, issues with substance use among adolescents has grown in its prevalence, and past research has shown a continuity in substance use amongst children with substance involved parents. In adolescence, young men tend to report higher rates of alcohol use when compared to young women. As such, we were interested in examining gender as a moderating factor on the relationship between parental alcohol use and substance use severity. Amazon’s MTurk was used to recruit 185 participants with a history of substance use to complete a series of surveys. Participants reported parental alcohol use during childhood and involvement with pro-social peers. Results revealed gender did not moderate the relationship between parental substance use and respondents’ self-reported substance use. However, there were strong correlations among substance use severity, parental alcohol use, and involvement with pro-social peers. Specifically, respondents who were the child of a mother who experienced problems with alcohol were 3.12 time more likely to have a severe SUD. This effect was not observed when paternal alcohol use was examined as a predictor of substance use severity (p = .651). Respondents involved with pro-social peers are less likely to have a severe substance use disorder (p < .001). Together, children whose mothers struggled with alcohol use were more likely to develop a severe substance use disorder. In contrast, having a father who struggled with alcohol use did not affect respondents’ involvement with substance use. Furthermore, having a peer support system reduces subsequent substance use, regardless of parental alcohol use.

The reintroduction of captive-bred animals has been increasingly utilized for the conservation of many species. However, few studies have focused on the importance of environmental factors and resource availability in the success of wildlife reintroductions. The goal of this study was to see if location influences the short-term reintroduction success of captive-bred Texas horned lizards (Phrynosoma cornutum). Specifically, I monitored diets, growth rates, and survival of over 250 lizards reintroduced to 2 locations in Mason Mountain Wildlife Management Area (Mason County, TX) for 3 months. Diet, growth rates, and survival all differed between the two locations. The findings of this study suggest that environmental factors can play an important role in the reintroduction success of Texas horned lizards. Future research will focus on identifying specific habitat characteristics that may contribute to the observations of this study such as prey availability, vegetation, thermal habitat quality, and soil permeability.

Antibiotic resistance has been increasing rapidly; however, the amount of new and effective antibiotics is declining. One area of growing interest is the use of metal nanoparticles because they are relatively easy to make and can be synthesized into different shapes, sizes, and with various chemical properties. In particular, zinc oxide nanoparticles have shown to be effective against various bacterial strains; however, the mechanism that zinc oxide utilizes to exhibit its antimicrobial activity is still unknown. It is also not clear what properties of zinc oxide such as size or proximity to bacterial cells are critical for its antimicrobial activity. In order to gain a better understanding of the mechanism behind zinc oxide’s antimicrobial activity, we tested Staphylococcus aureus with various zinc oxide particles under different conditions. Specifically, we looked at whether particle size, contact with bacterial cells, and media type influenced antimicrobial activity. Our results suggest that particle size does not influence zinc oxide activity, but media type significantly impacts antimicrobial activity. Physical contact, although more effective, is not absolutely required to see inhibition of bacterial growth. Understanding the mechanisms that zinc oxide utilizes may guide design for future particles that will improve their effectiveness.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease that is projected to affect almost 14 million American adults by the year 2050. While the prevalence of this detrimental disease is rapidly increasing in the United States, researchers have established the key pathologies connected to AD, including the development of extracellular, amyloid beta (Aβ) plaques, and intracellular, hyperphosphorylated, neurofibrillary tau tangles. Overall, AD engenders general atrophy of the brain and damage to key brain regions including the cerebral cortex and hippocampus, the main brain region responsible for the neural mechanisms of learning and memory. AD pathologies develop in these regions, which commonly results in neuronal death. The presence of AD pathologies, such as Aβ, activates microglial cells in the brain. Glial cells are the most common brain cells that provide support to neurons. Microglia specifically serve as resident immune cells in the brain, clearing cellular debris, such as dead neurons. Therefore, microglia play a key role in the progression of several neurodegenerative diseases. The activation of microglial cells results in an increased secretion of effector proteins, known as pro-inflammatory cytokines. These are released when inflammatory agents, such as Aβ, are present in the brain. Microglial cells commonly produce pro-inflammatory cytokines, such as TNF-α. Although microglial activation is advantageous at first, continual activation of microglial cells results in a constant inflammatory state. Chronic inflammation can lead to detrimental tissue damage that plays a vital role in neurodegeneration. Another key AD pathology, oxidative stress, is connected to chronic inflammation. Oxidative stress develops when the antioxidant system is unbalanced, resulting in the accumulation of reactive oxygen species (ROS). The presence of inflammatory agents and ROS have the potential to activate microglial cells. Accordingly, our lab utilizes microglial cells to study the harmful effects of inflammation on the brain. Dr. Kayla Green’s lab in the TCU Chemistry Department has successfully created compounds that act as potent antioxidants, L2 and L4. We collaborate with Dr. Green’s lab to research the possible rescue effects of L2 and L4 against inflammation in immortalized, BV2 microglial cells. In our lab’s previous research, we have demonstrated that both L2 and L4 have the capacity to rescue BV2 cells and increase cell survival during oxidative stress. Moreover, the main purpose of the current experiment is to further study the effects of these compounds against key AD pathologies, to understand their therapeutic potential against inflammation in vitro. In the current experiments, we utilized lipopolysaccharide (LPS), an element from the cell wall of gram-negative bacteria, to induce an inflammatory response in BV2 cells. First, we determined several timepoints and concentrations in which LPS treatment successfully induced the secretion of TNF-alpha. Next, we pre-treated cells with the compound, L4, for one hour prior to LPS treatment, to study the possible rescue effects of the drug against pro-inflammatory cytokine production. We are currently determining which concentration of L4 is the most therapeutic against pro-inflammatory cytokine production in BV2 cells.

Changes in thyroid hormones levels have been associated with alterations in somatic development and growth. However, recent studies have shown that alterations in thyroid hormone levels during early life stage (ELS) development can lead to long-term changes in reproduction. Specifically, fathead minnows that have been exposed to propylthiouracil (PTU) experienced a 50% reduction in fecundity. The purpose of this study was to determine if ELS thyroid disruption led to an alteration of reproductive behaviors in male fathead minnows. To accomplish this, larval fathead minnows were exposed to PTU and reproductive behaviors were quantified. Results showed that PTU-exposed fish demonstrated significantly fewer reproductive behaviors than those in the control group. This data provides an explanation for the previously observed 50% decrease in fecundity in the fathead minnows exposed to PTU and provides further evidence that ELS thyroid disruption can interfere with the display of key and ecologically-relevant behaviors later in life.

The rainbow trout, Oncorhynchus mykiss, is a partially migratory organism, that has been used recently to study the genetic control of migration. Much of this research has taken place at a unique site in Sashin Creek, Alaska, where the resident O. mykiss population is completely isolated from the migratory population. However, it is unknown the extent to which findings here are shared with other populations. Here we used a fine-scale genome-wide sequencing approach known as pooled sequencing to gather genetic data from 174 fish in two locations – Sashin Creek, Alaska and Little Sheep Creek, Oregon. Four sequenced pools were developed based on phenotype and population. We then measured differentiation between the populations to identify regions that may be correlated with the resident or migratory phenotype in both populations. We were able to locate 8 genes in 16 regions of shared elevated FST, and 17 genes over 16 regions with a significant Tajima’s D value that were specific to either the migratory or resident phenotype. These findings indicate specific genes and chromosomal regions that may be important in the regulation of migratory tendency in this species.

Mercury (Hg) is found in the environment in excess of historic baselines throughout the globe because of widespread atmospheric emissions of inorganic mercury (IHg) from anthropogenic sources such as coal-fired power plants and artisanal gold mines. In aquatic ecosystems, Ihg deposited from the atmosphere is converted by bacteria to methylmercury (MeHg), a bioavailable neurotoxin that adversely affects the health of vertebrates including humans and wildlife. Because IHg deposition varies across the landscape, it is necessary to monitor MeHg levels in aquatic food webs of individual waterbodies. This is a challenge because there are millions of river miles and lakes in the U.S. Shoreline spiders that feed on MeHg-contaminated emergent aquatic insects have been proposed as sentinel species to monitor MeHg contamination. Sentinel species are species which serve to map the bioavailable fraction of pollution in an ecosystem by retaining the pollutants in their tissue. The objective of this study was to test the hypothesis that shoreline spiders can be used as sentinels to evaluate MeHg contamination of river food webs. Our study focused on the Clear and West forks of the Trinity River. A pilot study in 2016 indicated the two forks have different levels of MeHg contamination. From June to August 2019, we collected over 1000 long-jawed orb weaver spiders (Tetragnathidae) along the shorelines of the two forks of the river. Spiders were preserved in 95% ethanol and sorted by leg length into different size categories. Mercury was analyzed using direct Hg analysis. Concentrations of Hg in spiders increased with spider size and was higher in the Clear Fork than the West Fork. A follow up study confirmed that fish in the Clear Fork had higher concentrations of MeHg than in the West Fork. This is one of the first studies to demonstrate that shoreline spiders can be used as sentinels of MeHg contamination in river ecosystems.

Across North America, bats are being killed in large numbers at wind energy facilities and there is concern that this level of mortality threatens bat populations. Currently three species of migratory tree bats, including two Lasiurus species, comprise ~75% of all known fatalities; however, as wind energy development expands into new areas (e.g., the southwestern U.S.) there is the potential for new species to be impacted. Ongoing work in our labs has indicated that that our current understanding of the distribution of Lasiurus species across North America is limited, at best, and that more species are impacted by wind energy development than previously thought. Accurate knowledge about which species are being impacted where, and to what extent, will greatly improve the implementation of effective mitigation strategies. We obtained 19 bat fecal samples from wild-caught Lasiurus bats from a study being conducted at Texas State University to improve the species-specific effectiveness of an ultrasonic acoustic deterrent (UAD) at deterring bats from approaching operational wind turbines. Based on morphology, these wild-caught bats were identified as eastern red bats (L. borealis), but it is possible that some of the individuals were western red bats (L. blossevillii). We extracted DNA from the bat fecal samples and amplified the COI mitochondrial gene to determine the correct species identification for each sample. The final sequencing reactions are underway, and the results will be available soon. These data will improve the accuracy of the results from the flight cage study at Texas State University and will contribute to improving strategies to reduce bat fatalities at wind energy facilities.

Although wind energy facilities are a growing source of renewable, clean energy, they have been shown to contribute to increasing bat mortalities which could threaten the persistence of bat populations. This study aims to expand what we know about the biology and behavior of bat species impacted by wind energy development. Recent research has indicated that yellow bats (Lasiurus spp) are killed at wind energy facilities in the Rio Grande Valley of south Texas. We have limited understanding of the population biology or movement patterns in these species, so the extent to which wind turbine mortality may impact these bats is currently unknown. As part of ongoing research in our labs, I extracted DNA from 18 tissue samples collected from northern yellow bats (Lasiurus intermedius) at a wind energy facility in Willacy county, Texas in 2015. I amplified a region of the mtDNA, the COI locus, and will compare genetic diversity of these samples to a larger data set from wind energy facilities in nearby Starr and Hidalgo Counties that were studied in 2016 and 2017. Together, these datasets will improve our understanding of Lasiurus intermedius genetic diversity and population structure, and have the potential to provide much needed insights into the potential impacts of wind energy development on bats in southern North America.

The student hasn't submitted any abstract yet.

Mutations in BReast CAncer 1 protein (BRCA1) play a crucial role in DNA damage control such as double-strand DNA break repair mechanisms. Mutations in BRCA1 increase the chance of disrupted genetic integrity by its contributions to the development of breast cancer. BRCA1 must bind to its partner protein PABL2 (Partner and Localizer to BRCA2) in order to properly carry out its function in the repair mechanism pathway, but its conformation once bound to PALB2 is not clear. In its inactive state, PALB2 is known to remain in an alpha-helical coiled-coil homodimer conformation. Through this observation, we hypothesized that the intrinsically disordered region of BRCA1 on its binding surface will undergo a conformational change into an alpha-helical form. In order to test this hypothesis, we first created a truncated BRCA1, making it 50 amino acids long, then conducted nuclear magnetic resonance (NMR) experiments. Through the NMR experiments, we found that the binding interface of BRCA1 does change its conformation into a helical state, forming a coiled-coil heterodimer upon binding with PALB2.

The proper functioning of the protein PALB2 is vital to preventing tumor formation within breast tissues in individuals. Upon the detection of DNA damage, PALB2 and BRCA1 bind to each other along with BRCA2 to form a DNA repair complex. This complex then repairs DNA double-strand breaks in order to prevent the accumulation of DNA damage that leads to breast cancer. While both BRCA1 and BRCA2 have been extensively studied, a lot of information about the structure and function of PALB2 remains unknown. It is thought that BRCA1 and PALB2 bind via PALB2’s coiled-coil domain; however, how variants of unknown significance (VUS) affect this binding interaction is largely unknown. Further, while some of these VUS have been studied in vivo, cheaper and easier in vitro methods to measure their effect on binding affinity have yet to be formulated. Thus, we hypothesized that isothermal titration calorimetry (ITC) could be used as an in vitro testing method for assessing the effects of VUS within the coiled-coil domain of PALB2 on the binding event between PALB2 and BRCA1. Further, we hypothesized that a decrease in binding between the two proteins as measured by ITC would correlate with a decrease in DNA repair as measured in vivo. We tested the efficacy of this method by creating seven mutations within the coiled-coil domain of PALB2 and measuring the binding event of PALB2 to BRCA1 via ITC. Our results strongly suggest that the binding event is enthalpic in nature and can be adequately measured via ITC as evidenced by the correlation between our in vitro data and previous in vivo data.

Evaluating sex-specific differences in cellular immune function in a small fish model, the fathead minnow

Andrew Mielcuszny
Department of Biology

Advisor: Dr. Marlo Jeffries

Previous studies in the Jeffries lab have shown that male and female fathead minnows differ in their ability to fight and survive bacterial infections. Specifically, males have significantly higher rates of mortality upon infection than females. Despite this, few studies have sought to identify the sex-specific differences in specific immune processes that underlie the observed differences in survival following pathogen infection. The purpose of this study was to examine the sex-specific differences in phagocytic cell activity, a key innate immune response in which immune cells engulf and destroy pathogens. To evaluate phagocytic cell activity, kidney cells were isolated from male and female adult fathead minnows and their ability to phagocytose fluorescently-labeled E. coli was measured. The relative phagocytic cell activity of male and female fathead minnows will be presented in an effort to explain whether differences in phagocytosis contribute to differences in pathogen resistance.

Mercury (Hg) is found in the environment in excess of historic baselines throughout the globe because of widespread atmospheric emissions of inorganic mercury (IHg) from anthropogenic sources such as coal-fired power plants and artisanal gold mines. In aquatic ecosystems, Ihg deposited from the atmosphere is converted by bacteria to methylmercury (MeHg), a bioavailable neurotoxin that adversely affects the health of vertebrates including humans and wildlife. Because IHg deposition varies across the landscape, it is necessary to monitor MeHg levels in aquatic food webs of individual waterbodies. This is a challenge because there are millions of river miles and lakes in the U.S. Shoreline spiders that feed on MeHg-contaminated emergent aquatic insects have been proposed as sentinel species to monitor MeHg contamination. Sentinel species are species which serve to map the bioavailable fraction of pollution in an ecosystem by retaining the pollutants in their tissue. The objective of this study was to test the hypothesis that shoreline spiders can be used as sentinels to evaluate MeHg contamination of river food webs. Our study focused on the Clear and West forks of the Trinity River. A pilot study in 2016 indicated the two forks have different levels of MeHg contamination. From June to August 2019, we collected over 1000 long-jawed orb weaver spiders (Tetragnathidae) along the shorelines of the two forks of the river. Spiders were preserved in 95% ethanol and sorted by leg length into different size categories. Mercury was analyzed using direct Hg analysis. Concentrations of Hg in spiders increased with spider size and was higher in the Clear Fork than the West Fork. A follow up study confirmed that fish in the Clear Fork had higher concentrations of MeHg than in the West Fork. This is one of the first studies to demonstrate that shoreline spiders can be used as sentinels of MeHg contamination in river ecosystems.

For this project, I mapped potential river otter habitat in the Dallas/Fort Worth metroplex based on literature data on known river otter habitat preferences in Texas. I will use this data along with GIS data on land use/cover/vegetation and distance from suitable water bodies, to determine where in the DFW river otters may prefer to live. This project is interesting and informative because in recent years more urban run-ins with river otters have been documented in the DFW. So knowing where they might like to be is good information for citizens to have, as river otters continue to make a comeback in numbers in the state of Texas.

Carnivorous plants inhabit nutrient-poor environments and supplement nutrient acquisition by capturing and digesting insect prey. Carnivorous adaptations have been hypothesized to be beneficial only in environments with high water and light availability. We hypothesized that plant morphology would change in response to resource availability, exhibiting traits that increase carnivory when light is abundant and exhibiting traits that increase photosynthesis when light is limited. In a field manipulation in Leon County, Texas, we examined the effects of feeding, shading, and their interaction on the morphology of the pitcher plant, Sarracenia alata. We employed a two-factor, cross-classified design, with shading (two levels, shaded and unshaded) and prey capture (two levels, fed and unfed) as factors. Eighty plants were haphazardly assigned to one of four treatments: (1) unshaded and fed (control); (2) shaded and fed; (3) unshaded and unfed; and (4) shaded and unfed. When light availability was reduced, plants produced pitchers that had smaller diameters, which is reflective of a photosynthetic morphology. Unfed plants exhibited reduced growth (produced fewer pitchers and had lower sum of pitcher heights). There was a significant interaction effect on estimated seasonal aboveground biomass: shading had no effect on the mass of unfed plants, but shading reduced the mass of fed plants. As the season progressed, competing vegetation reduced light availability to all pitchers. Plants in all treatments began to produce pitchers that were blade-like with a small, non-functional opening and a widened keel. This morphology would maximize light capture at the expense of prey capture. This experiment provides support for a theoretical model that suggests that carnivorous traits are only beneficial under conditions of high light availability. It also emphasizes the importance of periodic burns of carnivorous plant bogs to remove vegetation, thereby reducing light competition.

In recent years, macrocycles have emerged to be potential drug leads, as they show to have promise for targeting disease pathways, however their synthesis is quite difficult and has yet to be optimized. Utilizing glycine specifically in macrocycle synthesis was the objective, and this was done by stepwise reactions of successfully adding compounds onto glycine to prepare for cyclization. Cyanuric chloride, BOC-hydrazine, and morpholine were successfully added to glycine, as proven with thin layer chromatography and NMR. However, problems that arose came with purifying the compound for cyclization due to solubility issues. Many attempts utilized column chromatography, but there seems to be promise in utilizing an extraction to purify the compound and prepare for cyclization.

Micellization is a phenomenon of central importance in surfactant solutions. Here, we demonstrate that the diffusion-based spreading of the free boundary between a micellar aqueous solution and pure water yields a one-dimensional spatial profile of surfactant concentration that can be used to identify the critical micelle concentration, here denoted as C*. This can be achieved because dilution of micelles into water leads to their dissociation at a well-defined position along the concentration profile and an abrupt increase in diffusion coefficient. Rayleigh interferometry was successfully employed to determine C* values for three well-known surfactants in water at 25 ºC: Triton X-100 (TX-100), Sodium Dodecyl Sulfate (SDS), and Polyoxyethylene(4)Lauryl Ether (Brij-30). The dependence of C* on salt concentration was also characterized for TX-100 in the presence of Na2SO4, NaCl, and NaSCN. Accurate values of C* can be directly identified by visual inspection of the corresponding concentration-gradient profiles. To apply the method of least squares to experimental concentration profiles, a mathematical expression was derived from Fick’s law and the pseudo-phase separation model of micellization with the inclusion of appropriate modifications. While Rayleigh interferometry was employed in our experiments, this approach can be extended to any experimental technique that yields one-dimensional profiles of surfactant concentration. Moreover, diffusion-driven surfactant disaggregation is precise, non-invasive, requires single-sample preparation, and applies to both non-ionic and ionic surfactants. Thus, this work provides the foundation of diffusion-driven dilution methods, thereby representing a valuable addition to existing techniques for the determination of C*.

Organic dyes with photophysical properties affected by alterations in the properties of the media, including viscosity, temperature, and polarity, are known as environment-sensitive probes. These probes are widely used in various areas of analytical, biological and material sciences. This poster will describe our initial efforts on designing multi-responsive environment-sensitive probes based on squaric acid scaffolds. Specifically, the incorporation of aminoquinoline moieties produced small molecule viscometers, which have the ability to sense polarity variations of organic solvents. Multiplexing abilities, coupled with modular and facile synthesis, distinguishes these probes from other types.

Oxidative stress is a result of an imbalance between reactive oxygen species (ROS) and the availability/activity of antioxidants. The catalase family of enzymes mitigate the risk from ROS by facilitating the disproportionation of hydrogen peroxide into molecular oxygen and water. Manganese containing catalase (MnCAT) consists of a binuclear manganese core bridged by carboxylate and single-atom ligands, likely water or hydroxide. In this work, hydrogen peroxide disproportionation using complexes of manganese with cyclen and pyclen were investigated due to the spectroscopic similarities of the latter with the native MnCAT enzyme. Potentiometric titrations were used to construct speciation curves to identify what complex compositions were present at different pH values. Based on these results, the complexes were made in situ by mixing stock solutions of ligand, buffer, and metal. The hydrogen peroxide disproportionation reaction was carried out in a sealed cell and PO2 measured using a microsensor (Unisense). When hydrogen peroxide was injected into the cell, disproportionation activity of the complexes was evident by (1) appearance of bubbles in solution, and (2) noticeable increase in PO2 as measured by the sensor. Spectroscopic investigation before, during, and after the reaction was used to follow changes in the UV-visible absorption of the complexes to collect information about the structure of the initial catalyst and any possible intermediate. Both, pyclen and cyclen were determined to form a dimeric structure under the reaction conditions used.