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“Mycoremediation” of PFAS: application of wood decay fungi and natural wood substrates to investigate the tolerance, degradation, and sequestration capacity of fungi for perfluorocarboxylic acids:
No full textUniversity of Minnesota Ph.D. dissertation. May 2025. Major: Bioproducts/Biosystems Science Engineering and Management. Advisor: Jiwei Zhang. 1 computer file (PDF); vii, 86 pages.The widespread and large-scale manufacture and use of per-and polyfluoroalkyl substances (PFAS) since the 1950’s has led to globally ubiquitous contamination of the environment with PFAS and PFAS precursors. These fluorinated contaminants demonstrate extreme resilience to degradation and therefore do not meaningfully degrade when introduced to the environment. Exposure to these compounds is associated with numerous negative health outcomes. The development of novel remediation methods tailored to address these compounds is required as traditional technologies are generally poorly suited to the task. An alternative approach to supplement existing and developing physicochemical remediation technologies is the application of biological treatment methods. Bioremediation techniques utilizing microbes or enzymes are currently poorly developed, with limited examples of microbes with the capacity to degrade PFAS. This is especially true for fungal organisms. To address this knowledge gap, an appropriate fluoride detection method and an ideal fungal model are required. Therefore, we systematically evaluated methods for quantifying free fluoride anions and detecting and quantifying PFAS compounds under cultural conditions ideal for fungal species. Thereby, addressing the first requirement for the investigation of fungal PFAS degradation, identification of a suitable method to quantify PFAS removal, and to confirm defluorination; a prerequisite for meaningful biodegradation of PFAS. Next, through fungal screening via exposure to selected PFAS an appropriate model fungus was selected with the capacity to tolerate PFAS. Finally, PFAS degradation and defluorination was measured under solid and liquid culture methods using the selected methodology. The capacity to degrade and remove PFAS was confirmed leading to the development and investigation of a fungal-based sorbent system and investigation of PFAS sequestration by wood-based sorbents. This work contributes to the field of PFAS bioremediation, highlighting the importance of defluorination for the treatment of these compounds, and it draws attention to the role understudied fungi play in determining the environmental fate of PFAS and the potential they possess for the development of novel treatment techniques.Ayers, Charles. (2025). “Mycoremediation” of PFAS: application of wood decay fungi and natural wood substrates to investigate the tolerance, degradation, and sequestration capacity of fungi for perfluorocarboxylic acids:. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278048
Minutes: Faculty Consultative Committee: December 4, 2025
No full textIn these minutes: Open Discussion (mostly about ICE activity in the Twin Cities); Discussion with President Cunningham, Discussion with Provost RitterUniversity of Minnesota: Faculty Consultative Committee. (2025). Minutes: Faculty Consultative Committee: December 4, 2025. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278939
The role of estradiol in astrocyte and neuron communication
No full textUniversity of Minnesota Ph.D. dissertation. January 2025. Major: Neuroscience. Advisors: Alfonso Araque, Paul Mermelstein. 1 computer file (PDF); ix, 116 pages.No longer considered passive players in the brain, astrocytes are now appreciated for their active role in neural communication. The “tripartite synapse” depicts the bidirectional communication between the presynaptic, postsynaptic neuron and the neighboring astrocyte. An important characteristic of this astrocyte-neuron communication is the astrocyte responsiveness to neurotransmitters and the subsequent intracellular calcium mobilization. This intracellular calcium signal triggers the release of gliotransmitters that, activate neuronal receptors, and thereby regulate synaptic function. Most studies on the tripartite synapse have focused on classic neurotransmitters. However, whether other signaling molecules, such as hormones and specifically estrogen, signal to astrocytes and participate in the tripartite synapse function remains largely unknown. To address this knowledge gap, I used an in situ hybridization technique known as RNAscope to examine estrogen receptor (ER) expression in the nucleus accumbens core (NAcC) and CA1 of the hippocampus (Hipp) of adult female and male mice. I then used calcium imaging techniques in hippocampal slices to monitor astrocyte calcium activity in situ and to test whether astrocytes responded to the estrogen 17β-estradiol (E2). Lastly, I used electrophysiology to test whether E2-evoked astrocyte activity could regulate neuronal activity and excitatory synaptic transmission.
I describe results in Chapter 3 showing that females and males express ERα and ERβ in CA1 Hipp astrocytes. Females expressed overall more ERs on astrocytes than males. Both females and males predominately expressed ERβ compared with ERα. I was also able to show that E2 increased calcium event frequency in males and females via activation of estrogen receptors ERα and ERβ and the IP3R2 pathway. Lastly, I showed that E2 triggers the release of the gliotransmitters glutamate and ATP/adenosine, which increases the frequency of postsynaptic slow inward currents and depressed excitatory synaptic transmission, respectively.
In Chapter 4, I show the results of experiments using the same RNAscope and calcium imaging techniques to test whether E2 signals to nucleus accumbens core astrocytes. I found a small subpopulation of ERs in NAcC astrocytes, with females showing more ER expression than males. Females expressed more ERα and males expressed more ERβ. I used calcium imaging to test whether E2 influenced NAcC astrocyte calcium activity, and I found no changes in event frequency or amplitude. Overall, the functional role of ERs in NAcC astrocytes needs to be explored.Goenaga, Julianna. (2025). The role of estradiol in astrocyte and neuron communication. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278174
Electric dipole moments within and beyond the Standard Model
No full textUniversity of Minnesota Ph.D. dissertation. June 2025. Major: Physics. Advisor: Maxim Pospelov. 1 computer file (PDF); x, 106 pages.Searches for electric dipole moments (EDMs) in fundamental particles, nucleons, atoms, and molecules provide a powerful test of fundamental symmetries. The smallness of the CP-violation in the Standard Model (SM) gives a clean background for the EDM experiments, making any non-zero signals of EDMs directly sensitive to the beyond Standard Model (BSM) physics. The interpretation of EDM experiments requires a wide range of inputs from particle physics, hadron physics, nuclear physics, to atomic physics. In this thesis, a series of work on the theory of EDMs from the point of view of particle physics is presented. Starting from the Kobayashi-Maskawa (KM) phase in the SM, the size of the electron-spin-dependent CP-odd electron-nucleon interaction (usually denoted as the Cₛ operator), which contributes to the EDMs of paramagnetic systems, is calculated. The result is three orders of magnitude larger than previously believed. Using the QCD sum rule technique, arbitrary choices of the interpolating current are shown to lead to inconsistent results in the calculations involving the QCD theta term, and the proper procedure is identified to solve this issue. In the presence of EDMs of heavy SM fermions, the effective CP-odd operators generated below the heavy fermion mass threshold and the further induced neutron and atomic EDMs are derived, which in turn allows indirect constraints on the muon, charm quark, and bottom quark EDMs to be set based on existing experiments.Gao, Ting. (2025). Electric dipole moments within and beyond the Standard Model. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278168
Development of a versatile, endothelialized microfluidic platform to investigate vaso-occlusion in sickle cell disease
No full textUniversity of Minnesota Ph.D. dissertation. January 2025. Major: Biomedical Engineering. Advisor: David Wood. 1 computer file (PDF); xii, 164 pages.Sickle cell disease (SCD) is an inherited autosomal recessive disorder caused by a mutation in the hemoglobin β gene, leading to hemoglobin polymerization, red blood cell sickling, and a cascade of pathophysiological events that culminate in a painful vaso-occlusive crisis (VOC). Despite its discovery over a century ago, treatment options for the millions of SCD patients worldwide remain remarkably limited, thus highlighting the need for a better understanding of its underlying mechanisms. Recently, increased attention has been directed to hypoxia/ischemia reperfusion injury as a driving mechanism of VOC in SCD pathology. While hypoxia and reperfusion are classically thought to induce harmful inflammatory responses associated with apoptosis and symptom onset, a remarkable trait of reperfusion injury is that certain mild or cyclic periods of low oxygen may instead provoke a conditioning effect that ameliorates subsequent severe reperfusion injury. A better understanding of the conditioning effect exerted by hypoxia reperfusion on the endothelium may inform our overall understanding of SCD pathophysiology and offer insight towards therapeutic intervention. Existing in vivo and in vitro models do not reliably inform clinical trials, consequently more physiologically relevant models are needed to explore these fundamental questions about SCD pathophysiology. Therefore, we developed a microfluidic platform that includes three-dimensional endothelial-lined microchannels with physiologically relevant shear stresses in an oxygen-tunable environment. These features enable simulation of hypoxia reperfusion and vasoocclusion on-chip. We utilized fluorescence microscopy to validate the biological relevance of the endothelial vascular network on-chip, demonstrating appropriate lumen formation, alignment under flow, and cellular function. This microfluidic platform is unique in its ability to recapitulate many of the physiologic components of SCD. Its applications are two-fold: (1) its use as an occlusion assay that quantifies the occlusion incidence of patient blood samples through microvasculature, and (2) its potential to leverage next generation sequencing to explore genomic changes to the endothelium. Using the platform, we demonstrated that endothelial hypoxic preconditioning initiates a protective effect that reduces incidence of sickle red blood cell occlusion on-chip. We observed average vaso-occlusion rates of 8.89% and 11.78% after cyclic and sustained hypoxia preconditioning compared to 57.93% and 55.05% for atmospheric and physiologic controls, respectively. Moreover, we investigated endothelial gene regulation via RNA sequencing to identify pathways of interest and specific genes that may directly contribute to this protective result. These results offer a better understanding of the mechanistic changes affecting the endothelium during hypoxia reperfusion injury and also support the hypothesis that hypoxia preconditioning may offer a protective effect against VOC in SCD.Schad, Samantha. (2025). Development of a versatile, endothelialized microfluidic platform to investigate vaso-occlusion in sickle cell disease. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278075
Cross-correlation of stochastic gravitational wave background and galaxy number counts and Its angular power sectrum
No full textUniversity of Minnesota Ph.D. dissertation. September 2025. Major: Physics. Advisor: Vuk Mandic. 1 computer file (PDF); viii, 108 pages.In this dissertation, I present my study of the cross-correlation between the anisotropy in stochas- tic gravitational-wave background (SGWB) and the distribution of galaxies across the sky. This study will improve the sensitivity of future searches for anisotropy in the SGWB and expand the use of SGWB anisotropy to probe the formation of structure in the Universe. It has three parts.First, I use the spherical harmonic decomposition of the anisotropic SGWB measured in the second observing run (O2) of LIGO in 50 Hz-wide frequency bands and convert them into pixel-based sky maps in HEALPIX basis. Then I take the galaxies in the Sloan Digital Sky Survey (SDSS) photometric and spectroscopic catalog in 0.1-wide redshift bins and count them in pixels of HEALPIX basis to form number count sky maps at the same angular resolution as the SGWB maps. I compute the pixel-based coherence between the SGWB maps in frequency bands and galaxy count maps in redshift bins and find that the coherence is dominated by the null measurement noise in the SGWB maps and is not statistically significant.
Second, I use the anisotropic SGWB measured in the first three observing runs (O1-O3) of LIGO in 10 Hz-wide frequency bins and galaxy count over-density from the SDSS spec- troscopic catalog without binning in redshift to compute the angular power spectra of their auto-correlations and cross-correlation. I compare the observed cross-correlation to the spec- tra predicted by astrophysical models. I apply a Bayesian formalism to explore the parameter space of the theoretical models, and I set constraints on a set of astrophysical parameters of the astrophysical kernel describing the galactic process of gravitational-wave (GW) emission with or without the inclusion of shot noise.
Third, I estimate the amplitude and spatial anisotropy in the SGWB energy density due to compact binary coalescence (CBC) events occurring in galaxies in the Flagship Mock Catalogue developed by the Euclid Consortium. For each galaxy in the catalogue, I use the simulated stellar mass and star formation to constrain the galaxy’s star formation history and predict its contribution to the SGWB. I also compare these predictions to the astrophysical models above and explore the parameter space with an ideal covariance dominated by cosmic variance to set constraints on the parameters.Yang, Kate. (2025). Cross-correlation of stochastic gravitational wave background and galaxy number counts and Its angular power sectrum. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278768
Evolution of reproduction of crickets in extreme environments: offspring investment and mate-finding strategies in Hawaiian lava crickets and the Pacific field cricket
No full textUniversity of Minnesota Ph.D. dissertation. July 2025. Major: Ecology, Evolution and Behavior. Advisor: Marlene Zuk. 1 computer file (PDF); ix, 89 pages.Individuals that can mitigate survival costs by adaptively allocating resources towards reproduction over the course of their lifetime are likely to be favoured by selection. Under an extreme environment or a sudden change in selection pressures due to a novel challenge, the trade-off between reproduction and survival is crucial in determining the persistence of populations. My dissertation uses varied approaches to explore how extreme environments alter reproductive investment using two crickets that inhabit distinct extreme environments; one found barren lava fields with harsh environmental conditions and limited nutrition, and the second that is currently adapting to a novel ecological pressure (a parasitoid fly that eavesdrops on its host’s sexual signals). First, I study wingless extremophile Hawaiian lava crickets Caconemobius spp. to describe aspects of its reproductive investment into offspring production (chapter 1) and mate-finding (chapter 2), to understand how this species persists in its extreme environment. Next, I capitalize on a novel case of rapid sexual signal loss in the Pacific field cricket Teleogryllus oceanicus, where males have lost the ability to produce sexual signals due to the introduction of a parasitoid fly. To understand the consequences of this rapid change in the acoustic environment experienced by these crickets, I study whether the perception of future mate availability influences how female invest into current and future reproduction through their egg-laying patterns (chapter 3). Finally, I use agent-based models to determine how different male mate-finding strategies found in these populations may exert selective pressures on each other (chapter 4). Together, this work contributes to a broader understanding of how reproductive investment can be altered by novel and extreme environments, a topic of much importance in our rapidly changing world.Thadi, Aarcha. (2025). Evolution of reproduction of crickets in extreme environments: offspring investment and mate-finding strategies in Hawaiian lava crickets and the Pacific field cricket. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278095
Exploring the chemical mechanisms and applications of plasma-driven solution electrochemistry using pulsed DC, atmospheric pressure plasma with a liquid electrode
No full textUniversity of Minnesota Ph.D. dissertation. August 2025. Major: Chemistry. Advisor: Renee Frontiera. 1 computer file (PDF); xviii, 151 pages.Plasma-driven solution electrochemistry (PDSE) is the use of charged reducing and oxidizing agents generated by a plasma discharge to drive redox chemistry in solution. The analogy is to standard electrochemistry where a bias is generated across electrodes in solution to drive redox chemistry. In the case of a plasma system, the plasma can inject high-energy electrons or charged ions directly into solution to drive comparable reactions. There have been many reported uses of PDSE to drive reactions such as metal salt reduction to form nanoparticles or facilitate organic chemical degradation. There is significantly less known about the applications of PDSE for driving synthetic reactions to generate value added organic molecules from organic feedstock. A few efforts have formed polymeric materials or molecular dimers, but the mechanisms behind these reactions are less understood. In this work, I will discuss my efforts to understand the mechanisms behind observed PDSE reactions, explore further chemical applications, and develop novel techniques for further research. I was able to show that plasma can be used to drive the oxidation of aqueous aniline to form a pentameric oligomer. I studied the reaction through sequestration experiments to show that the reaction was predominantly driven by plasma-generated superoxide. I also show my efforts to develop a plasma-driven Birch reduction reaction in aqueous solution by harnessing the solvated electrons generated by the plasma discharge. I show that there are not clear conditions that can facilitate the reaction and discuss the advancements necessary to study this matter further. I also present the progress made to develop a time-resolved stimulated Raman spectroscopy technique to measure the chemical kinetics of the liquid phase following a single plasma pulse.Clay, Collin. (2025). Exploring the chemical mechanisms and applications of plasma-driven solution electrochemistry using pulsed DC, atmospheric pressure plasma with a liquid electrode. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278148
Expression of the tooth mineralization gene Amelx in mandibular osteoclasts: experimental study
No full textUniversity of Minnesota M.S. thesis. 2025. Major: Dentistry. Advisor: Kim Mansky. 1 computer file (PDF); vi, 37 pages.Aim: Confirm a mandibular-derived population of CD11b+ cells express Amelx, a gene involved in tooth mineralization.
Methods: Mouse monocytes and osteoclasts were analyzed by qRT-PCR to determine if Amelx was expressed in cells from the mandible and femur bone marrow. Mouse craniofacial tissue sections and multinuclear osteoclasts cultures were stained by immunofluorescence for the presence of AMELX.
Results: Monocytes and osteoclasts from the mandible of 2-month-old mice showed significant expression of tooth mineralization genes Amelx, Ambn, and Enam. Multinuclear osteoclasts cultured from mandibular-derived bone marrow were positive for AMLEX expression. Femur monocytes and osteoclasts did not have any detectable expression of Amelx as measured by qRT-PCR or immunofluorescence.
Conclusions:The mandible contains a subpopulation of monocytes and osteoclasts that express Amelx. It is not evident what functions Amelx+ mandibular osteoclasts perform in craniofacial bone, but they may play a role in tooth eruption, alveolar bone remodeling, and/or the regulation of enamel formation.Keesler, Ryan. (2025). Expression of the tooth mineralization gene Amelx in mandibular osteoclasts: experimental study. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/277976
Key components for lanning and developing new pharmaceutical enterprises that produce COVID-19 vaccines in Nigeria for local uptake
No full textUniversity of Minnesota Ph.D. dissertation. 2025. Major: Social and Administrative Pharmacy. Advisors: Olihe Okoro, Caroline Gaither. 1 computer file (PDF); ix, 128 pages.The COVID-19 pandemic reignited global conversations around vaccine access, underscoring the urgent need for local manufacturing capacity in low- and middle-income countries. Despite its large population and growing pharmaceutical sector, Nigeria relied entirely on imported COVID-19 vaccines. This study investigates the critical components necessary to establish a vaccine manufacturing enterprise capable of meeting domestic demand in Nigeria. A mixed-methods design was employed, combining interviews with six senior stakeholders in the regulatory and pharmaceutical sectors and a survey of 335 adults in Lagos State. Qualitative data were thematically analyzed to explore institutional, regulatory, and workforce-related barriers. Quantitative analysis assessed demographic predictors of public willingness to accept a locally produced COVID-19 vaccine. Interview participants identified core challenges including inadequate technical workforce, poor infrastructure, limited political support, and regulatory delays. Survey results showed that 76 percent of respondents would accept a Nigerian-made COVID-19 vaccine, with significantly higher acceptance among older adults and Muslim participants. Factors such as gender, employment, and educational attainment were not statistically associated with vaccine acceptance. This study contributes to ongoing discourse on regional vaccine self-reliance by offering an integrated analysis of supply-side constraints and demand-side readiness in an urban Nigerian context. These findings provide context-specific insights to support strategic planning, capacity building, and trust-building measures needed for sustainable local vaccine production.Aremu, Taiwo. (2025). Key components for lanning and developing new pharmaceutical enterprises that produce COVID-19 vaccines in Nigeria for local uptake. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278213