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Physiological tradeoffs occur in organisms coping with their environments, which are likely to increase as populations reach peripheries of established ranges. Invasive species offer opportunities to study tradeoffs that occur, with many hypotheses focusing on how immune responses vary during dispersal. The cane toad (Rhinella marina) is a well-known invasive species. Populations near the expanding edge of the Australian invasion have altered immune responses compared to toads from longer-established core populations, although this has not been well-documented for Florida populations. In this study, cane toads from a northern edge [New Port Richey (NPR)] and southern core (Miami) population in Florida were collected and injected with lipopolysaccharide (LPS) to compare immune responses. Core population individuals injected with LPS showed greater metabolic increases compared to their baseline rates that were higher compared to those from the edge population. In addition, LPS-injected core individuals had different circulating leukocyte profiles compared to saline-injected cane toads while edge individuals did not. There was a significant interaction between plasma bacteria-killing capability (BKA) and treatment, such that BKA decreased with time in saline compared to LPS-injected individuals, and saline-injected toads from the edge population had lower BKA compared to LPS-injected edge toads at 20 h post-injection. There was also a significant interaction between location and time on circulating corticosterone (CORT) levels following injections with saline or LPS, with CORT decreasing more with time in core population toads. The differential CORT response indicates that differential stress responses contribute to the tradeoffs observed with immunity and dispersal.

Cane Toads (Rhinella marina) are an invasive species introduced to southern Florida, USA, and populations have spread northward through the state. Populations established near expanding edges of their distributions are predicted to have greater endurance, an indicator of dispersal capability, than longer established populations. To assess endurance, we collected Cane Toads from a northern (edge) and southern (core) population in Florida, placed them into a track, and prodded them to hop. The number of prods (taps), hops, and time spent hopping were recorded, along with the total distance each toad moved on the track. Edge population toads were less willing to move and did not travel as far in the track as those from the core population. To further evaluate endurance, we placed an additional set of toads inside a treadmill, where movement was required to maintain equilibrium. Toads moved on the treadmill until reaching exhaustion. We measured blood lactate levels from each toad upon exhaustion and during a 3-h recovery period. After the treadmill trials, there was no population effect on the distances traveled by toads. There was also no population effect on lactate levels of toads when reaching exhaustion or during recovery. Overall, Cane Toads from our sampled northern edge population showed no differences in endurance compared to those sampled from the southern population in this study. This finding may indicate that further dispersal is limited in the northernmost populations of the Cane Toad range in Florida. Furthermore, the reluctance of Cane Toads to move in the track trials may indicate that selective pressures differ for edge populations in Florida.

To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK), and evaluate their possible implications for corneal biomechanics. A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left)/28 (right) years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal)×0.25 mm (vertical) intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas. Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident. Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft-host interface in the long term.

Cane toads are highly toxic bufonids invasive in several locations throughout the world. Although physiological changes and effects on native predators for Australian populations have been well documented, Florida populations have received little attention. Cane toads were collected from populations spanning the invaded range in Florida to assess relative toxicity, through measuring morphological changes to parotoid glands, likelihood of secretion, and the marinobufagenin (MBG) content of secretion. We found that residual body indices increased in individuals from higher latitude populations, and relative parotoid gland size increased with increasing toad size. There was no effect of latitude on the allometric relationship between gland size and toad size. We observed an increase in likelihood of secretion by cane toads in the field with increasing latitude. Individuals from southern and northern populations did not vary significantly in the quantity of MBG contained in their secretion. Laboratory‐acclimated cane toads receiving injections of epinephrine were more likely to secrete poison with increasing dose, although there was no difference in likelihood of secretion between southern and northern populations. This suggests that differences between populations in the quantities of epinephrine released in the field, due to altered hypothalamic sensitivity upon disturbance, may be responsible for the latitudinal effects on poison secretion. Our results suggest that altered pressures from northward establishment in Florida have affected sympathetic sensitivity and defensive mechanisms of cane toads, potentially affecting risk to native predators. Predators in the United States have evolved in sympatry with native bufonids. Compared to Australia, little attention has been paid to gland morphology or toxicity of invasive cane toads in Florida. Although we found no effect of locality on gland morphology or poison composition, our results indicate that northern FL populations show an increased likelihood of secreting poison when disturbed, and lab‐acclimated toads injected with epinephrine were more likely to secrete poison with increasing dose. This indicates sympathetic sensitivity has been altered in cane toads from establishment in northern FL.

[This corrects the article on p. e68166 in vol. 8.].

The technological achievements made with silicon-based transistors have led to nearly all the computing seen today, complete with benefits such as maximized operating speeds, parallel/tensor processing, minimized power overhead, etc. The silicon electronics industry is foundational to scientific progression with its profound impact on modeling, simulations, and fast/reliable computing. However, silicon-based transistors have evolved to meet their physical limitations and have saturated fields of innovation. New fields in computing outside of silicon-based methods have emerged as exotic materials enter the research domain. The suite of super-performing materials like Graphene, Carbon Nanotubes, and Molybdenum Disulfide have chaotic, non-linear behaviors that make utilization as a computing element possible. With silicon technology well-established, exploration into alternative approaches has proliferated with important outputs such as quantum-dot, spintronics, and physical machine learning. The appeal of these are speed-of-light response times (photonics), nonvolatile memory (spintronics/quantum dot), and for physical machine learning, benefits include offline computing, irregular/flexible PCBs, low manufacturing costs, fast fabrication turnaround times, and eco-friendliness. The inherent limitations of silicon technology are addressed with alternative computing, applied as a supplemental/hybrid computing paradigm that perform in ways silicon-only approaches cannot. This work explores the newly emerged field of inkjet-printed electronics for alternative computing due to its compatibility with usage of unique nanoparticle materials, low fabrication costs, fast production times, environmental friendliness, and substrate variability. An inkjet-printed non-linear graphene element (IJPAN) is shown to compute within a well-known machine learning architecture as one of the first studies into machine learning systems using inkjet-printed neural networks as the hidden layer. Multiple non-linear elements are simulated as a network of identical nodes to replace the standard sigmoid layer (reservoir) of a Recurrent Neural Network called the Echo State Network. Inkjet-printer fabrication methods, error minimization, and evolution to the final artificial neuron are included for reproducibility. The impact to the scientific community is its application to edge-computing, cyber security, high-volume sensor networks, multi-physics perception, and irregular surfaces. Long term benefits to society include cost-effective, biodegradable, large-area, flexible, and offline electronics in telehealth, entertainment, safety equipment, home hobbies, and more.

Cytoplasmic mislocalization of the TAR-DNA binding protein of 43 kDa (TDP-43) leads to large, insoluble aggregates that are a hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). In this thesis work, we have characterized the interaction of the TDP-43 nuclear localization signal (NLS) with the classical nuclear import receptors importin α1 and importin β. We found that the NLS makes extensive contacts with importin α1, especially at the minor NLS-binding site. Correspondingly, the P2’ arginine (R83) at the minor site was necessary for binding to importin α1, while the P2 lysine (K97) at the major site was not. The R83 is near the globular N-terminal domain (NTD) of TDP-43, which we determined to dimerize at low concentration, and become increasingly oligomerized as NTD concentration increased. Complexation with importin α1 abolished this self-association of TDP-43, indicating that the importin α1 subunit possessed a novel disaggregating activity. Structural characterization of the TDP-43 interaction with importin α1 indicated that the C-terminus of importin α1 disrupts the TDP-43 NTD dimerization interface. We investigated the effect of phosphorylation within the TDP-43 NLS at T88, S91, and S92. Phosphomimetic mutation of these residues revealed that modification of T88 in the proximity of the minor binding site could reduce the affinity of the NLS for importin α1. Through molecular dynamics (MD) simulations, we found that phosphorylation of T88 destabilizes binding to importins by reducing the NLS backbone dynamics. Based on these data, we explain the pathogenic role of several post-translational modifications and mutations in the proximity of TDP-43 minor NLS site that are linked to disease and shed light on the chaperone activity of importin α1/β.

Physiological tradeoffs occur in organisms coping with their environments, which are likely to increase as populations reach peripheries of established ranges, potentially due to stress. Invasive species offer opportunities to study tradeoffs that occur, such as immune responses and defensive behaviors. The cane toad (Rhinella marina) is a well-known invasive species. Populations near the expanding edge of the Australian invasion have altered immune responses, increased leg and poison (parotoid) gland size, and decreased likelihoods of fleeing when disturbed compared to toads from longer established core populations, although this has not been well-documented for Florida populations. The research of this dissertation focuses on evaluating how immune, defensive, and endurance levels of cane toads from a northern edge (New Port Richey (NPR)) and southern core (Miami) population in Florida differ due to location in Florida. Core population individuals injected with LPS showed greater metabolic increases compared to their baseline rates that were higher compared to those from the edge population, and core individuals had different circulating leukocyte profiles compared to saline-injected cane toads while edge individuals did not. There was also a significant interaction between location and time on circulating corticosterone (CORT) levels following injections with saline or LPS, with CORT decreasing more with time in core population toads. We found that residual body indices increased in individuals from higher latitude populations, and relative parotoid gland size increased with increasing toad size. There was no effect of latitude on the allometric relationship between gland size and toad size. We observed an increase in likelihood of secretion by cane toads in the field with increasing latitude. Edge population individuals were less willing to move and did not travel as far in the track as those from the core population; however, there was no effect of locality on the distances traveled by toads in a treadmill. Although lactate levels decreased with time, there was also no effect of locality on lactate metabolism. The CORT responses of these toads observed in the field and in lab indicates that differential stress responses contribute to the tradeoffs observed with immunity, behavior, and dispersal.

This thesis presents the results and conclusions of experiments designed to extend the current models for the origin of corneal transparency. The cornea is the transparent window at the front of the eye, which is responsible not only for the majority of refraction of light that enters, but also the protection against damage, infection and mechanical stress. The property of transparency is only realised by corneal and lens tissue in the human body. In the cornea, it has long been suspected to be caused by the precise arrangement of the fibrils of collagen that are contained within the central layer, the stroma, regulated by the sulphated proteoglycans (PG) that keep fibril spacing within acceptable boundaries. These models are consistent and give a complete description of the reasons for the transparency of a stroma that is entirely acellular. However, it is well known that the stroma is not acellular, and that the short-range order that is critical for transparency would necessarily be disturbed by the cells of the stroma, the keratocytes, which are at least an order of magnitude thicker than the maximum allowed range. Originally, an acellular stroma was considered to be a reasonable approximation due to the perceived sparsity of the cells, but more recent measurements have cast doubt upon this, and explanations have begun to focus on the properties of the cells themselves. One such property would be their refractive index (RI). If the cells could match their own RI to that of their surroundings then they would not scatter and hence would not cause a loss in transparency. This research attempts to measure that RI and by comparison with previously calculated values for the RI of the extra-cellular matrix, attempts to quantify the scale of the scattering that any mismatch would cause, using theoretical models based on both Mie scattering and finite-difference time-domain methods. In addition to models of healthy corneas, this thesis also provides results and conclusions drawn from studies of pathological corneas and discussions of how the pathology, and the treatments, can cause initial losses in transparency. The first such study concerned a cornea afflicted with keratoconus, a disorder of as yet unknown origin that causes the weakening of the corneal tissue, leading to a characteristic cone-shaped cornea, which had been treated with a full penetrating keratoplasty (PK) transplant before being donated. The study was conducted using the techniques of electron microscopy and x-ray diffraction, to both qualitatively and quantitatively analyse the properties of the fibrils and their spacing. This was done on both the original sections of diseased tissue and the donated sections, in order to investigate the idea of keratoconus recurring in previously healthy donated tissue. Any such discovery could provide evidence that keratoconus is not an entirely inherited disorder. The structural properties of the observed scar, that was present as a direct result of the PK procedure that was carried out decades before, were also investigated using the same methods. This investigation was designed to provide insights into the priorities of wound healing in the cornea, and whether any appreciable change in fibril spacing could account for the observed loss of transparency. The final study presented here is a novel tomographic reconstruction of a feature of the disease macular corneal dystrophy (MCD). MCD is a genetic disorder that affects the sulphation of the PG keratan sulphate. MCD gives rise to a multitude of abnormalities but one that has not been fully investigated is the apparent presence of areas within the stroma entirely populated by PGs, with no collagen present. This study attempts to reconstruct three-dimensional views of these lakes, as well as stromal lamellae, in order to investigate the interactions between free PGs and between PGs and collagen in MCD.

A technological renaissance is underway, allowing large-area displays, paper thin sensors, flexible electronics and printable circuits. A new circuit manufacturing technique has the potential for a plethora of promising applications from non-invasive biosensors to radio-frequency identification tags (RFIDs). Functional layers are printed onto a planar substrate by inkjet printers retrofit with conductive inks, resulting in the inkjet-printed circuit (iPC). Functional RLC components have been designed with relatively high reliability, paving the way for fully printed passive and active analog filters. The main electrical component being researched to meet industrial standards is the printed transistor. This thesis establishes a digital model of a unique transistor, designed and printed in-house. The behavior of the device was mathematically generated from the analysis of manually collected analog data. DC analysis show this device did not function as a standard field-effect transistor, but rather as an entirely new device described as a bivariable resistor. While this device did not fulfill the expectations of a highly functional printed transistor, it did beget a unique device capable of sensing applications.