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Access to clean water is one of the world's foremost challenges that has been addressed on a large scale by membrane-based separation processes for the last six decades. Commercial membrane technology within one operation, reverse osmosis, has remained consistent since the late 1970s, however within the last two decades, access to nanotechnology has created a realm of study involving thin film nanocomposite (TFN) membranes, in which nanoparticles are incorporated into existing membrane designs. Desirable properties of the nanoparticles may positively impact qualities of the membrane like performance, anti-fouling behavior, and physical strength. In the present work, two types of nanoparticles have been evaluated for their potential as TFN additives: cellulose nanocrystals (CNCs) and metal-organic framework (MOF) nanorods. CNCs were chosen due to their high aspect ratios, mechanical strength, and potential for surface functionalization. MOF nanorods are also of interest given their aspect ratios and potential for functionalization, but they also possess defined pores, the sizes of which may be tuned with post-synthetic modification. Both CNCs and MOF nanorods were incorporated into TFN membranes via interfacial polymerization, and the resulting membranes were characterized using a variety of techniques to establish their performances, but also to gain insight into how the presence of each nanoparticle might be affecting the membrane active layer formation. A resulting CNC membrane (0.5 wt% loading) exhibited a 160% increase in water flux and an improvement in salt rejection to 98.98 ± 0.41 % compared to 97.53 ± 0.31 % for a plain polyamide control membrane. Likewise, a MOF nanorod membrane (0.01 wt% loading) with a high ratio of acid chain modification exhibited a 95% flux increase with maintained high salt rejection. For the CNCs, the flux increase is attributed to the formation of nanoscale voids along the length of each particle that form during the interfacial polymerization. These nanochannels introduce new rapid water transport pathways within the active layer of each membrane while maintaining ion rejection. The proposed mechanism for the MOF nanorods also introduces nanochannels into each membrane, but the presence of each nanorod's pore structure may offer another transport pathway for water molecules, one that varies with pore size. In combination, these results have allowed the study of molecular transport of water molecules and various ion species within the active layer of a thin film composite RO membrane. Understanding these phenomena will allow the development of smarter membrane materials to address present-day and future separations challenges. Carbon nanotubes are also demonstrated as surface modifiers for forward osmosis (FO) membranes to address issues unique to the FO process, namely reverse solute flux (RSF). This method shows promise, as a coating density of 0.97 g/m2 reduced RSF for many draw solution species, including a 55% reduction for sodium chloride. Doctor of Philosophy Access to clean water is one of the world's foremost challenges that has been addressed on a large scale by membrane-based separation processes for the last six decades. Commercial membrane technology within one operation, reverse osmosis, has remained consistent since the late 1970s, however within the last two decades, access to nanotechnology has created a recent realm of study in which nanoparticles are incorporated into existing membrane designs. It is desired to use nanotechnology, or nanoparticles to improve membrane performance, i.e. create a membrane with better rejection of unwanted ions or contaminants or improve the amount of water that passes through the membrane. In the present work, two types of nanoparticles have been evaluated for their potential as TFN additives: cellulose nanocrystals (CNCs) and metal-organic framework (MOF) nanorods. Both CNCs and MOF nanorods were incorporated into membranes and the resulting membranes were characterized using a variety of techniques to establish how the nanoparticles affected performance. A resulting CNC membrane (0.5 wt% loading) exhibited a 160% increase in water flux (the amount of water passing through an area in a given amount of time) and an improvement in salt rejection. Likewise, a MOF nanorod membrane with a high ratio of acid chain modification exhibited a 95% flux increase with maintained high salt rejection. For both the CNCs and the MOFs, these performance changes are attributed to new pathways within each membrane for water flow that exist due to the presence of the nanoparticles in each system. In combination, these results have allowed the study of transport of water molecules and various ion species in each membrane. Understanding these results will allow the development of smarter membrane materials to address present-day and future separations challenges.

Health disparities account for significant differences in mortality and morbidity risks in Central Appalachia (encompassing parts of WV, KY, TN and VA) compared to other U.S. regions, yet research addressing environmental factors potentially contributing to these health disparities is lacking. Central Appalachia offers a unique opportunity to examine environmental exposures associated with resource extraction. Coal production from large surface mines was the dominant resource extraction method in the 1990s-2000s and is now decreasing as other resource extraction methods increase. We hypothesize that health risks associated with air and water pollution exposure are greater for Central Appalachian residents living within close proximity to active surface mines. The results described here begins to link exposure with health outcomes using individual-level birth record data. We have extended spatiotemporal characterization of boundaries associated with surface mining between 1990 and 2015 in all Central Appalachia counties. Results indicate that from 1990 to 2015, 1806 km2 of land across the study area was disturbed by mining activities, which equates to approximately 4.2% of the study-defined Central Appalachia region. Temporal trends show a decreasing amount of active surface mining sites over the study period. Using a previously developed surface mining dataset that only covered southwest Virginia coalfields, we tested the hypothesis that maternal address proximity to active surface mining was positively associated with preterm birth. No significant association was found; however the sample size (n=5008) was very small due to poor geocoding rates, particularly in earlier years, and overall low number of births between 1990-2015 in this small, rural area (n=14,269). Our next steps will be to improve inference and precision in effect estimates by increasing sample size with inclusion of data from TN, KY and WV, application of the accuracy–assessed surface mining extent dataset described here to improve estimate of proximity to active surface mining, and inclusion of watershed boundaries, drinking water violation datasets, as well as airshed characterization. Ultimately, we hope this research will aid in determining the underpinnings of health disparities in Central Appalachian communities, ultimately leading to research, policy and practice improvements that may be generalizable to other rural areas beyond Central Appalachia.

Acetylation of key Lysine residues characterizes aggregates of the microtubule-associated protein tau constituting the neuropathological hallmark of many neurodegenerative diseases, such as Alzheimer's disease (AD) and Progressive Supranuclear Palsy (PSP). This has led to the idea that acetylation influences tau aggregation. Using a HEK293 cell-based aggregation assay, we tested whether acetylation-mimicking substitutions (K→Q) on five AD-associated acetyl-modified sites (AcK-311, 353, 369, 370, 375) influenced its propensity to aggregate when exposed to tau seeds derived from two clinically distinctive diseases - AD and PSP. In combination, the presence of 5K→Q sites ablated tau aggregation induced by seeds from both AD and PSP patients, indicating that acetylation within the filament core domain of tau could have an inhibitory effect on seed-mediated aggregation. We had previously identified that a phosphorylation-mimetic on Ser305 (S→E) abrogated tau aggregation by seeds from AD patients, without affecting seeding by PSP patients. Combining the S305→E to the 5K→Q acetyl-modified sites, we found that this tau could now be seeded only by PSP patients, but not by AD patients, confirming Ser305 as a critical determinant of strain-specific tau seeding. On the other hand, acetylation-nullifying substitutions (K→R or K→A) on these same Lys sites did not alter tau seeding abilities compared to the parental tau construct. Notably, the combined acetylation-nullifying Alanine substitutions on these 5 Lys sites resulted in spontaneous self-aggregation, with the filaments resembling amorphous deposits. All together, we demonstrate that cooperative acetyl-occupancy in the tau filament core influences seeded propagation of misfolded tau as well as drives self-aggregation., Competing Interests: Conflict of interest. The authors declare that they have no competing interests.