University of Tennessee Institute of Agriculture
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New Program Approval - Professional Advancement Through Hands-On Learning Undergraduate Certificate
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Effects of social dominance on perineuronal nets in medial prefrontal cortex and basolateral amygdala
Get PDFThe medial prefrontal cortex contributes to many aspects of social behavior including the establishment and maintenance of dominance relationships. The development of dominance relationships also generates experience-dependent plasticity in cortical circuits controlling future social behavior and responses to stress. Perineuronal nets (PNN) are specialized extracellular structures that surround cortical neurons and contribute to experience-dependent neuroplasticity. Using a Syrian hamster model, we investigated whether the development of dominance relationships alters the expression of PNNs in the infralimbic (IL) and prelimbic (PL) regions of the ventral medial prefrontal cortex (vmPFC), as well as the basolateral amygdala (BLA). In addition, we tested whether status-dependent changes in PNN expression predicted changes in agonistic behavior. Female and male hamsters were paired with a weight-matched conspecific and exposed to daily dominance interactions for two weeks. Brains were collected after the final dominance interaction and PNN expression was measured throughout the rostral-caudal extent of the IL, PL, and BLA. While pairs of hamsters readily formed stable dominance relationships, pairs differed in their expression of PNNs, particularly within the medial prefrontal cortex. Furthermore, PNN expression correlated with both early and late phase agonistic behavior, elucidating the role of PNNs in both establishing and maintaining dominance status
Gas Separation Properties of Ionic Liquids and Porous Liquids
No full textWith a constant rise in carbon emissions, developing effective gas separation techniques for carbon capture is critical for combating climate change. Type III porous liquids represent a promising new class of porous material that combines the free volume of porous solids and the nonvolatile properties of ionic liquids. The resulting permanent porosity can be used to adjust the gas separation properties of an ionic liquid, including the 2/2 selectivity and CO2 and N2 permeabilities. In this project, the zeolites Hydrogen-Zeolite Socony Mobil-5 (H-ZSM-5) and Sodium-Zeolite Socony Mobil-5 (Na-ZSM-5) were suspended in the ionic liquids, Trihexyltetradecylphosphonium bromide ([P66614][Br]) and 8,8′-(3,6-dioxaoctane-1,8-diyl)bis(1,8- diazabicyclo[5.4.0]undec-7-en-8-ium)bis(trifluoromethanesulfonyl)imide ([DBU-PEG][NTf2]) respectively. The membranes of the ionic liquids and their porous liquids at varying concentrations were tested and analyzed for their 2/2 selectivity and their CO2 and N2 permeabilities. The goal of this work is to understand the gas transport in porous liquids, explore how the addition of zeolites impacts gas separation of an ionic liquid, and assess how varying the concentration of free volume in the porous liquids influences gas separation performance. The results show that incorporating H-ZSM-5 with [P66614][Br] enhances the 2/2 selectivity as well as the CO2 and N2 permeabilities as the zeolite concentration increases. The addition of Na-ZSM-5 in [DBU-PEG][NTf2] improved the 2/2 selectivity but led to a decrease in CO2 and N2 permeabilities. These results demonstrate that the addition of zeolites into ionic liquids can be used to adjust gas separation properties for carbon capture
UNDERSTANDING THE ROLE OF THE HINGE DOMAIN IN INTERDOMAIN COMMUNICATION IN NUCLEAR HORMONE RECEPTORS
No full textThe thyroid hormone receptor (TR), a nuclear receptor (NR), acts as a ligand-mediated transcription factor. TR activity is modulated by interactions with the ligand 3,3’,5 triiodo-L-thyronine (T3), DNA, co-activators, and other NRs such as retinoid X receptor (RXR). Allostery is increasingly recognized among NRs as a common regulatory mechanism. Ligand-binding causes conformational changes in TR, enabling the recruitment of transcriptional coactivators and interact with the pre-initiation complex (PIC) for gene expression. Attempts at characterizing these structural changes in NRs have proven futile due to the presence of intrinsically disordered regions, such as the hinge domain. The hinge domain is poorly conserved throughout the nuclear receptor family. It links the ligand-binding domain (LBD) to the DNA-binding domain (DBD). Studies have shown that the presence or absence of DNA bound to the ligand-activated NR results in ‘open’ and ‘closed’ conformations of the receptor. The role of the hinge in this interdomain communication, however, remains unknown. This research elucidates the function of the hinge domain in these transcriptionally optimal orientations of TRα using single molecule studies and cell-based assays
COMPREHENSIVE FRAMEWORK FOR STRUCTURAL CONCRETE MIX OPTIMIZATION: INTEGRATING DIFFERENT AGGREGATE TYPES, GRADATION TECHNIQUES, AND PASTE CONTENT REDUCTION
No full textTraditional structural concrete mixes focus on individual aggregate sizes which leads to suboptimal mixtures that require excessive paste content, resulting in increased costs, higher carbon footprint, and potential durability issues. There is limited research on the workability challenges and solutions associated with these mixtures to find the optimal balance when paste content is reduced after optimization. So, there is a need for a systematic approach to find the optimal balance between aggregate optimization and paste content reduction while enhancing or maintaining workability, strength, and durability. Also, understanding the effects of different aggregate types on optimization techniques is needed to help engineers and concrete producers make more informed decisions when selecting materials for specific applications while using optimization techniques. This study investigates the effects of reduced paste content on the performance of optimized concrete mixtures for structural applications, while also examining the influence of different aggregate types on optimization techniques. Four different coarse aggregates (two granite, one limestone, and one gravel) and two fine aggregates (manufactured sand and natural sand) were used for optimized concrete using tarantula curve and coarseness factor chart methods. Optimized mixes were designed with 0%, 10%, and 20% reductions in cementitious content and compared to non-optimized control mixes. The study found that the optimization process led to improved freeze-thaw durability, higher compressive strengths, and better resistance to chloride ion penetration. However, there were some trade-offs, such as increased drying shrinkage due to partial replacement of coarse aggregates with intermediate aggregates. The results also indicate that while natural sand demonstrates superior performance compared to manufactured sand in terms of workability and durability, gravel and granite outperformed other coarse aggregate types by providing better compressive strength. While optimized mixes with a 20% reduction in paste content exhibited acceptable properties, a 10% reduction is recommended. This is due to the significantly higher demand for admixtures required in the 20% reduction mixes to maintain adequate workability. The 10% reduction strikes a better balance between sustainability, performance, and cost-efficiency, making it a more practical choice for structural concrete applications
Who, what, when, & where? Seasonally varying host traits influence persistence of a fungal pathogen in amphibian communities
No full textUnderstanding the conditions that enable pathogens to persist is instrumental for predicting disease dynamics and informing disease management strategies. Persistence results from complex interactions of system-specific traits that are often heterogeneous across the landscape and exhibit seasonal fluctuations. These spatiotemporal variations can profoundly affect the processes involved in pathogen persistence, necessitating the use of a modeling approach that can capture the complex and dynamic nature of such systems. In this paper, we develop a multi-host, seasonal model that can be parameterized using readily available field data to quantify the seasonal drivers of host persistence. Our model quantifies time-varying species contributions to pathogen persistence using the basic reproduction number R0. We parameterized our model using two years of empirical data on the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd) in eastern Tennessee, where the pathogen persists enzootically. Bd is responsible for worldwide declines in amphibian populations, and understanding how Bd persists has important implications for predicting disease trajectories and informing conservation efforts. We collected data on host abundance, Bd prevalence and intensity, and species spatial overlap throughout the year and used this data to parameterize our model. Using our model, we i) quantified the seasonal contribution of amphibian species to Bd persistence and ii) simulated the effect of removing a host species on community R0 to compare species-specific contribution to persistence among sites. We found that both ecological (abundance and species spatial overlap) and epidemiological traits (Bd prevalence and infection intensity) tended to shift seasonally. Due to these variations, host species-specific maintenance potential (R0) was also seasonally dependent. Moreover, host contributions to persistence differed between communities, with some hosts being dominant maintenance hosts at one site while contributing minimally to persistence at others. Notably, however, eastern newts (Notophthalmus viridescens), when present, demonstrated relatively high, although variable, maintenance potential compared to other species. Broadly, our results demonstrate that maintenance potential is not an intrinsic species characteristic and, instead, is seasonally and spatially dependent, emphasizing the importance of context for pathogen persistence
Summary of 2025 Public Acts
No full textThis document summarizes the year\u27s public acts that have the most impact on municipal operations in Tennessee
Growth and Characterization of Ligand Multivariate Metal–Organic Nanotubes
No full textLigand multivariance, or the incorporation of different ligands within one homogeneous material, has long been studied in metal-organic frameworks (MOFs). Metal-organic nanotubes (MONTs), a subclass of MOFs, share many properties and applications with MOFs. MONTs, however, possess only one dimension of growth, as opposed to the isotropic growth of most MOFs, and aggregate via weak interactions between individual tubes rather than covalent bonds as in MOFs. The role of these weak interactions was illuminated in this work through the growth of ligand multivariate MONTs, enabling MONT growth to be understood as a class of anisotropic materials.
Despite the similarities between MOFs and MONTs, ligand multivariance has not been studied in MONTs. Utilizing a semi-rigid di-1,2,4 triazole and its partially fluorinated analog as linking ligands, multivariate MONTs were synthesized in varying ratios. The resulting materials were shown to possess a statistically random mixture of the two ligands through a suite of nondestructive techniques.
The influence of neighboring ligands was further investigated through three binary combinations of ligands. Each formed a pure MONT possessing a differing amount of intertube interactions in the backbone. As MONT aggregation relies upon relatively weak intertube interactions, as opposed to the covalent bonds between ligands and the secondary building units (SBU)s of MOFs, understanding these interactions is a key differentiating factor between MONTs and MOFs.
To exploit MONTs as materials, their morphology and aggregation must be understood. To this end, MONTs were grown in solutions of varying polarity and protic or aprotic nature to tune their size and aspect ratio. In a second study, a ligand, its partially deuterated analog, and a MOF-forming di-triazole ligand were copolymerized and the growth mechanism was established via small angle neutron scattering.
These results lay the groundwork to exploit the sensitivity of MONT ligands to their surrounding tubes. With the mechanism of growth of multivariate MONTs, as well as the morphological tunability of pure MONTs established, future work aimed at exploiting the unique anisotropic properties of MONTs can be performed