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Novel Applications of Advanced Bioimaging: Quantification of Intrathecal Solute Transport to the Brain and Magnetic Resonance Imaging of Ophthalmic Structural Changes in Long Duration Spaceflight Astronauts
No full textThe field of bioimaging science has been continually evolving over the recent years. Typically, bioimaging is used to noninvasively visualize biological processes in real time at multiple resolutions. Commonly used imaging techniques include those based in optics, photonics, magnetic resonance, spectroscopy, and others. Imaging processing and analysis are an integral part of bioimaging and allows for the quantification of anatomical and physiologically relevant parameters. In this thesis, we propose two novel applications of bioimaging: (1) quantification of intrathecal solute transport to the brain in a human model and (2) quantification of ophthalmic structural changes in long duration spaceflight astronauts. To address the first aim, a T2-weighted magnetic resonance imaging (MRI) sequence was used to acquire anatomical and cerebrospinal fluid (CSF) flow data. An optically clear 3D in vitro human model of the CSF in the subarachnoid space and subject specific oscillatory CSF flow waveforms were developed from the sequence. Several intrathecal drug delivery (ITDD) parameters, including (a) bolus volume and rate, (b) flush volume, timing, and rate, (c) injection location, and (d) type of device, were investigated. It was observed that a parametric increase in flush volume had the greatest impact on increasing solute transport to the brain. The findings of this study provide insight into the relationship between the anatomy and physiology of the CSF dynamics and ITDD injection parameters, which potentially allows for an improved detection and treatment of central nervous system disorders. To address the second aim, noninvasive MRI based techniques were developed to assess and quantify ophthalmic changes in healthy subjects under head down tilt as an analog to microgravity. This is critical as spaceflight has been shown to induce structural ophthalmic abnormalities in a condition known as Spaceflight Associated Neuro-ocular Syndrome (SANS). Prohibitive costs and physical limitations of inflight monitoring has created challenges in studying the pathology of SANS. Therefore, head down tilt (HDT) studies are currently being studied as spaceflight analogues due to its ability to simulate similar fluid redistributions observed in microgravity. In this study, HDT studies were used to quantify structural ophthalmic changes. Specifically, the following changes were quantified: (a) change in optic nerve sheath (ONS) and optic nerve (ON) cross sectional area, (b) change in ON deviation, (c) change in vitreous chamber depth, (d) an estimated Young’s modulus, and (e) change in posterior globe volume displacement. The findings observed suggest that the CSF pressure was elevated in the bulbar subarachnoid space; however, the non-linear behavior of the soft tissue suggests that further increases in pressure may not lead to further ophthalmic changes. Furthermore, the effect of centrifugation as a countermeasure was investigated and no significant difference between the treatment groups was observed, suggesting that mitigation techniques may not be sufficient to reduce the severity of SANS.masters, M.S., Biological & Agricultural Engineering -- University of Idaho - College of Graduate Studies, 2021-1
Indentation Investigation of 304L Stainless Steel Friction Stir Weld Simulated Crack Repair and Software Development for Rapid Processing of Indentation Data
No full textSimulated cracks were repaired in 304L stainless steel using low temperature friction stir welding. Indentation studies were carried out to understand the effect of microstructural features on the mechanical property variation across the weld and to measure the size of the weld zones with a quantitative technique. Microhardness and nanoindentation hardness profiles were constructed on a transverse section across the weld. The data obtained were correlated by extrapolating the nanoindentation hardness to greater depths which showed that the nanoindentation hardness closely reflects the microhardness values throughout the weld. Hardness contour maps, with adequate resolution, revealed that nanoindentation can detect material flow induced features, like: “lazy-S” and onion rings. Grain size in the stir zone (SZ) was found to vary with the tool temperature which, in turn, alters the nanoindentation modulus variability and higher tool temperature resulted in softening and widening of the SZ. Comparing nanoindentation elastic contour maps suggest that temperature significantly effects the crystallographic texture development across all zones of the FSW. Four data processing Graphical User Interfaces were developed, using Python, to process the raw data files of the microhardness and nanoindentation tests.masters, M.S., Mechanical Engineering -- University of Idaho - College of Graduate Studies, 2021-1
The Role of Social Norms in Producers’ Motives to Adopt Sustainable Practices
No full textSustainable practices in the agricultural sector have become a prerequisite for operating in current markets as well as a source for building and sustaining a competitive advantage through better market positioning. Producers and processors in the agricultural sector have to make various decisions on the adoption of sustainable practices, whereby their choices and behaviour are affected by different types of norms: social and personal norms. This article examines the influence of social norms on the expected economic, social, and personal rewards, that may drive producers towards the adoption of sustainable practices. We have developed a framework in which we distinguish between two types of social norms: horizontal norms (reliant on peer influence) and vertical norms (imposed by transactional and hierarchical relationships). We focus on horizontal, vertical, and personal norms and analyze its impact on expected economic, social, and personal motives by using Seemingly Unrelated Regression (SUR) Model. Result from personal interviews with 164 hog producers show that horizontal social norms have a positive influence on both social and economic motives of farmers whereas vertical social norms have positive influence only on the farmer’s social motives. In addition, personal norms have a significant positive relationship with personal motives.masters, M.S., Agricultural Economics and Rural Sociology (Applied Economics) -- University of Idaho - College of Graduate Studies, 2021-0
Comparative Phylogeography of Pacific Northwest Gastropods
No full textComparative phylogeography is the study of the effects of biogeography and evolutionary history on the spatial distribution of genetic variation of codistributed species. This approach allows investigation of the links between population processes and regional patterns. Here, I present three comparative phylogeographic studies, each focused on different assemblages of gastropod species that are endemic to the temperate rainforests of the North American Pacific Coast and Northern Rocky Mountain interior regions. Slug and snail endemism in these areas is high and several factors are likely responsible for generating the high levels of diversity. The results suggest that codistributed species likely exhibit distinct patterns that reflect the unique aspects of species’ phylogeographic histories, which emphasizes that phylogeographic structure is complex and is shaped by more than just a few abiotic factors. In addition, the results presented here significantly increase the taxonomic and natural history knowledge of several rare gastropod lineages, which is important because there is an increasing need to obtain data on the genetic and spatial structure of endemic taxa in areas such as the Pacific Northwest.doctoral, Ph.D., Bioinformatics & Computational Biology -- University of Idaho - College of Graduate Studies, 2021-0
Exploring Faculty Perceptions of a Professional Development Program for Online Teaching and Learning in an Intentional Community of Practice: A Phenomenological Study
No full textThe purpose of this phenomenological study was to explore faculty experiences with a professional development program designed to prepare them for improved online teaching and learning. The research question was: how do faculty perceive their experiences in a professional development program designed to prepare them for better online teaching and learning in an intentional community of practice? The review of literature for this study focused on the following topics: (1) issues in teaching online in higher education, (2) faculty professional development, (3) effects of team-based professional development interventions in higher education, (4) conditions for successful professional development activities in teams, (5) communities of practice, and (6) related frameworks. A qualitative phenomenological approach was applied in this study. Participants were selected through a purposeful sampling method. In-depth, semi-structured interviews were used to collect narrative data from eight identified participants. An analysis of collected data revealed four emergent themes: (1) obtaining new knowledge, (2) confirmation of appropriate tools and strategies, (3) mixed learning experience, and (4) community bond. Although the participants’ academic backgrounds varied, most of them obtained new technological and pedagogical knowledge by participating in the professional development program. Some participants reaffirmed their previous knowledge; for those faculty members, the professional development program was a reinforcement of appropriate tools and strategies. Additionally, participants had mixed feelings about their learning experience. Some participants perceived the program as beneficial, while others felt the program repetitive. Furthermore, participants perceived a community bond. The investigation concluded with recommendations for future research.doctoral, Ph.D., Curriculum & Instruction -- University of Idaho - College of Graduate Studies, 2021-0
An Analysis Of A Dump Heat Exchanger For The Versatile Test Reactor’s Secondary Loop
No full textThe VTR is a new research reactor that uses a Dump Heat Exchanger (DHX) to transfer heat from sodium to the surrounding air. A DHX is used in place of a power cycle for a testing reactor to displace the heat from the secondary loop. An analysis of the existing heat exchanger, a cross-flow design, was completed. Possible heat exchanger options, a shell-and-tube and an annulus heat exchanger, were investigated. Using Aspen HYSYS several iterations of analysis were completed. Sodium data from Argonne National Laboratory (ANL) was inputted into HYSYS to be used with all the models. It was found that having a slower flow rate for air passing through the heat exchanger was instrumental to improving the initial cross-flow design. Upon comparing the other design types with the initial cross-flow design based on footprint, volume of material, and weight, the shell and tube heat exchangers were the best option followed by the annulus heat exchangers and finally the original cross-flow design. Out of two possible shell and tube heat exchanger designs investigated the one that contained 100 tubes was the better option.masters, M.S., Nuclear Engineering -- University of Idaho - College of Graduate Studies, 2021-1
Globodera pallida Control Using Brassica juncea Seed Meal Extract and the Trap Crop Solanum sisymbriifolium
No full textGlobodera pallida, the pale cyst nematode, is a regulated potato pest with the potential for detrimental economic impacts. Restrictions on use of the soil fumigant, methyl bromide, and lack of resistant russet type varieties for US markets have led to investigations of alternative strategies to control this potato pest. The efficacy of Brassica juncea seed meal extract (SME) was evaluated under greenhouse conditions (0, 0.14, 0.28, 0.56, 1.12, and 2.24 t SME/ha) and field conditions (0, 1.12, and 2.24 t SME/ha in year 2019 and 0, 0.14, 0.28, 0.56, and 1.12 t SME/ha in year 2020) either applied alone or in combination with the trap crop Solanum sisymbriifolium. The impact of the application of SME pre- or post-planting S. sisymbriifolium was determined. Solanum sisymbriifolium alone reduced the number of encysted eggs compared to the untreated control by up to 60% in greenhouse and 67% in field trials. When SME was applied post-planting, S. sisymbriifolium induced hatch of G. pallida and significantly fewer encysted eggs remained at termination of the experiment whether or not SME was applied. When SME was applied pre-plant, the remaining encysted eggs were not decreased by planting S. sisymbriifolium which may indicate that SME inhibited egg hatch in the presence of S. sisymbriifolium. Treatments with SME either alone or with S. sisymbriifolium provided a significant reduction of G. pallida egg viability, hatch, and reproduction compared to the untreated control at all rates tested under greenhouse conditions. Combined treatment with S. sisymbriifolium and SME at lower rates, 0.14 t/ha for pre-plant or 0.56 t/ha or less for the post-plant experiment, further reduced egg hatch and reproduction than each treatment alone. SME alone applied at higher rates of 1.12 and 2.24 t/ha whether or not combined with S. sisymbriifolium eliminated G. pallida reproduction on potato in both pre-plant and one post-plant greenhouse trials. In the second post-plant greenhouse trial, SME at 1.12 t/ha and 2.24 t/ha when applied alone highly reduced the reproduction factor compared to the untreated control by 64 and 89%, respectively, and eliminated reproduction when used in combination with S. sisymbriifolium. Collectively, our results indicated that a combination of SME and S. sisymbriifolium allows an opportunity to reduce the amount of SME required to control G. pallida and further decrease the potential reserve of the viable population remaining after individual treatment with each strategy.masters, M.S., Plant, Soil and Entomological Sciences -- University of Idaho - College of Graduate Studies, 2021-0
Stability of Proteins and Organic Acids in Production of Milk Protein Concentrate (MPC) and Milk Protein Isolate (MPI) and Effect of Temperature and Time on Functional Properties of MPC and MPI
No full textMilk is a complex food containing many constituents in a variety of forms, like fat in an emulsion, proteins in colloidal dispersion, and lactose and minerals in a soluble phase. Each milk component has its own biological, nutritional, and technological significance. Milk is one of the most complete foods nutritionally being rich in protein, fat, carbohydrates, vitamins and minerals essential for sustaining life and maintaining good health. Milk proteins contribute to functional properties such as solubility, emulsion formation, and foaming ability and stability for products in food systems utilizing dairy ingredients. Processing such as heating and drying during production of milk protein concentrates (MPC) can affect milk proteins. MPCs have become common dairy ingredients because of their nutritional quality and functionality. A variety of organic acids (e.g., lactic, citric, and orotic) are also present in milk. Organic acids are important because they contribute to the flavor and aroma of dairy products. Organic acids are also used as additives to stabilize or increase the palatability of dairy products. Many organic acids in dairy products originate from the metabolism of larger organic compounds such as lipids, proteins, and carbohydrates. Stability of proteins and organic acids during production of MPC was evaluated. The quantity of various proteins and organic acids in raw milk, nanofiltration product (NF) and MPC-80 and milk protein isolate (MPI)-85 powder was analyzed by reverse phase-high performance liquid chromatography. MPC-80 is a specific dairy ingredient category containing 80% protein on “as is” basis while MPI-85 is another category containing 85% protein on a “dry matter” basis. Concentrations of the major caseins (α-CN and β-CN) were increased in NF compared to raw milk and further increased in MPC-80 and MPI-85. The concentration of κ-CN was greater in NF compared to raw milk but not different in MPC-80 or MPI-85. Most whey proteins (α-lactalbumin, β-lactoglobulin, IgM) were similar in concentration between raw milk and MPC-80 as well as between raw milk and MPI-85. The major caseins (α-CN and β-CN) were greater in concentration in MPI-85 than MPC-80.The effects of storage temperature and time on the solubility of MPC-80 and MPI-85 were investigated using solubility tests, emulsification, foaming ability and stability, viscosity and gelation time on powder stored at 25 ℃ and 55 ℃ for 49 d. Over time, storage at 55 ℃ compared to 25 ℃ reduced solubility of MPC-80 and MPI-85 but no difference was detected in solubility between MPC-80 and MPI-85. Emulsions made from either MPC-80 or MPI-85 stored at 25 °C had no visibly detectable separation or instability but emulsions stored at 55 °C had clear separation of cream and water with sedimentation of powder. Viscosity increased across all days of storage in MPC-80 and MPI-85 stored at 55 ℃ compared to that stored at 25 ℃. Foaming ability and stability of MPC-80 and MPI-85 were reduced during storage at 55 ℃, presumably due to the reduction in powder solubility. Gelation time increased in MPC-80 and MPI-85 stored at 55 ℃ compared to powder stored at 25 ℃. Overall, greater storage temperature adversely affected functionality of MPC-80 and MPI-85 with little difference between the milk powders. Preventing reductions in functionality of milk protein concentrates during storage at higher temperatures would likely aid in the economic value of these dairy ingredients. Key words: milk, milk protein concentrate, protein, organic acids, functionalitymasters, M.S., Animal and Veterinary Science -- University of Idaho - College of Graduate Studies, 2021-0
Context-Dependent Effects of Nutrition and Dam Behavior on Neonatal Survival in a Long-Lived Herbivore
No full textBehavior represents one of the primary mechanisms by which animals overcome environmental constraints on survival and reproductive success. Females in particular often exhibit plastic behavioral strategies for coping with the different nutritional demands and degrees of susceptibility to predation imposed by gestation, parturition and lactation. Previous studies have demonstrated a link between space-use behavior and important correlates of fitness and have highlighted the value of mechanistic nutritional approaches for understanding the fitness consequences of behavior. However, the mechanisms by which individual responses to variation in the nutritional landscape scale up to influence population performance remain unclear. We quantified relationships among the nutritional landscape (i.e., spatiotemporal variation in forage biomass), dam behavior, and neonatal survival in bighorn sheep (Ovis canadensis). We conducted intensive vegetation sampling and used generalized additive modeling to map the nutritional landscapes available to sheep during summer (May–September) in three population ranges in Idaho: Owyhee River, East Fork of the Salmon River, and Lost River Range. We used GPS collars and lamb surveys to monitor ewe behavior and lamb survival in each study area, and used known-fate survival modeling to test for behaviorally mediated effects of nutrition on lamb survival. Relationships among the nutritional landscape, ewe behavior, and lamb survival were context dependent and varied among study sites. In the Lost River, where lamb survival was highest (83.9%), probability of lamb survival increased when ewes traded access to rugged terrain for access to higher forage biomass. We observed the opposite pattern in the East Fork (i.e., probability of lamb survival increased when ewes traded access to forage for access to rugged terrain), however, and in the Owyhee no metric of ewe behavior was significantly related to the probability of lamb survival. We also observed a strong, positive relationship between spring nutritional condition and probability of lamb survival across study sites. Our research helps to establish mechanistic links among habitat heterogeneity, individual space-use behavior, and reproductive success in bighorn sheep, and underscores the fundamental importance of nutrition as a driver of ungulate performance. Continuing to improve our understanding of such relationships will provide valuable insights for managers and conservationists, and will aid in accurately parameterizing models of population dynamics. Maximizing the usefulness of such models requires knowledge of the mechanisms that underpin variation in population demographics, and nutritional-ecological approaches like those used in our study shed important light on those mechanisms.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2021-0