Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
Displaying 1 - 10 of 85
Description
Background: Evidence about the purported hypoglycemic and hypolipidemic effects of nopales (prickly pear cactus pads) is limited. Objective: To evaluate the efficacy of nopales for improving cardiometabolic risk factors and oxidative stress, compared to control, in adults with hypercholesterolemia. Design: In a randomized crossover trial, participants were assigned to a 2-wk intervention with 2 cups/day of nopales or cucumbers (control), with a 2 to 3-wk washout period. The study included 16 adults (5 male; 46±14 y; BMI = 31.4±5.7 kg/m2) with moderate hypercholesterolemia (low density lipoprotein cholesterol [LDL-c] = 137±21 mg/dL), but otherwise healthy. Main outcomes measured included: dietary intake (energy, macronutrients and micronutrients), cardiometabolic risk markers (total cholesterol, LDL-c, high density lipoprotein cholesterol [HDL-c], triglycerides, cholesterol distribution in LDL and HDL subfractions, glucose, insulin, homeostasis model assessment, and C-reactive protein), and oxidative stress markers (vitamin C, total antioxidant capacity, oxidized LDL, and LDL susceptibility to oxidation). Effects of treatment, time, or interactions were assessed using repeated measures ANOVA. Results: There was no significant treatment-by-time effect for any dietary composition data, lipid profile, cardiometabolic outcomes, or oxidative stress markers. A significant time effect was observed for energy, which was decreased in both treatments (cucumber, -8.3%; nopales, -10.1%; pTime=0.026) mostly due to lower mono and polyunsaturated fatty acids intake (pTime=0.023 and pTime=0.003, respectively). Both treatments significantly increased triglyceride concentrations (cucumber, 14.8%; nopales, 15.2%; pTime=0.020). Despite the lack of significant treatment-by-time effects, great individual response variability was observed for all outcomes. After the cucumber and nopales phases, a decrease in LDL-c was observed in 44% and 63% of the participants respectively. On average LDL-c was decreased by 2.0 mg/dL (-1.4%) after the cucumber phase and 3.9 mg/dL (-2.9%) after the nopales phase (pTime=0.176). Pro-atherogenic changes in HDL subfractions were observed in both interventions over time, by decreasing the proportion of HDL-c in large HDL (cucumber, -5.1%; nopales, -5.9%; pTime=0.021) and increasing the proportion in small HDL (cucumber, 4.1%; nopales, 7.9%; pTime=0.002). Conclusions: These data do not support the purported benefits of nopales at doses of 2 cups/day for 2-wk on markers of lipoprotein profile, cardiometabolic risk, and oxidative stress in hypercholesterolemic adults.
ContributorsPereira Pignotti, Giselle Adriana (Author) / Vega-Lopez, Sonia (Thesis advisor) / Gaesser, Glenn (Committee member) / Keller, Colleen (Committee member) / Shaibi, Gabriel (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2013
Description
In this research, our goal was to fabricate Josephson junctions that can be stably processed at 300°C or higher. With the purpose of integrating Josephson junction fabrication with the current semiconductor circuit fabrication process, back-end process temperatures (>350 °C) will be a key for producing large scale junction circuits reliably, which requires the junctions to be more thermally stable than current Nb/Al-AlOx/Nb junctions. Based on thermodynamics, Hf was chosen to produce thermally stable Nb/Hf-HfOx/Nb superconductor tunnel Josephson junctions that can be grown or processed at elevated temperatures. Also elevated synthesis temperatures improve the structural and electrical properties of Nb electrode layers that could potentially improve junction device performance. The refractory nature of Hf, HfO2 and Nb allow for the formation of flat, abrupt and thermally-stable interfaces. But the current Al-based barrier will have problems when using with high-temperature grown and high-quality Nb. So our work is aimed at using Nb grown at elevated temperatures to fabricate thermally stable Josephson tunnel junctions. As a junction barrier metal, Hf was studied and compared with the traditional Al-barrier material. We have proved that Hf-HfOx is a good barrier candidate for high-temperature synthesized Josephson junction. Hf deposited at 500 °C on Nb forms flat and chemically abrupt interfaces. Nb/Hf-HfOx/Nb Josephson junctions were synthesized, fabricated and characterized with different oxidizing conditions. The results of materials characterization and junction electrical measurements are reported and analyzed. We have improved the annealing stability of Nb junctions and also used high-quality Nb grown at 500 °C as the bottom electrode successfully. Adding a buffer layer or multiple oxidation steps improves the annealing stability of Josephson junctions. We also have attempted to use the Atomic Layer Deposition (ALD) method for the growth of Hf oxide as the junction barrier and got tunneling results.
ContributorsHuang, Mengchu, 1987- (Author) / Newman, Nathan (Thesis advisor) / Rowell, John M. (Committee member) / Singh, Rakesh K. (Committee member) / Chamberlin, Ralph (Committee member) / Wang, Robert (Committee member) / Arizona State University (Publisher)
Created2013
Effect of a Wii Fit® intervention on balance, muscular fitness, and bone health in middle-aged women
Description
Sustaining a fall can be hazardous for those with low bone mass. Interventions exist to reduce fall-risk, but may not retain long-term interest. "Exergaming" has become popular in older adults as a therapy, but no research has been done on its preventative ability in non-clinical populations. The purpose was to determine the impact of 12-weeks of interactive play with the Wii Fit® on balance, muscular fitness, and bone health in peri- menopausal women. METHODS: 24 peri-menopausal-women were randomized into study groups. Balance was assessed using the Berg/FICSIT-4 and a force plate. Muscular strength was measured using the isokinetic dynamometer at 60°/180°/240°/sec and endurance was assessed using 50 repetitions at 240°/sec. Bone health was tracked using dual-energy x-ray absorptiometry (DXA) for the hip/lumbar spine and qualitative ultrasound (QUS) of the heel. Serum osteocalcin was assessed by enzyme immunoassay. Physical activity was quantified using the Women's Health Initiative Physical Activity Questionnaire and dietary patterns were measured using the Nurses' Health Food Frequency Questionnaire. All measures were repeated at weeks 6 and 12, except for the DXA, which was completed pre-post. RESULTS: There were no significant differences in diet and PA between groups. Wii Fit® training did not improve scores on the Berg/FICSIT-4, but improved center of pressure on the force plate for Tandem Step, Eyes Closed (p-values: 0.001-0.051). There were no significant improvements for muscular fitness at any of the angular velocities. DXA BMD of the left femoral neck improved in the intervention group (+1.15%) and decreased in the control (-1.13%), but no other sites had significant changes. Osteocalcin indicated no differences in bone turnover between groups at baseline, but the intervention group showed increased bone turnover between weeks 6 and 12. CONCLUSIONS: Findings indicate that WiiFit® training may improve balance by preserving center of pressure. QUS, DXA and osteocalcin data confirm that those in the intervention group were experiencing more bone turnover and bone formation than the control group. In summary, twelve weeks of strength /balance training with the Wii Fit® shows promise as a preventative intervention to reduce fall and fracture risk in non-clinical middle aged women who are at risk.
ContributorsWherry, Sarah Jo (Author) / Swan, Pamela D (Thesis advisor) / Adams, Marc (Committee member) / Der Ananian, Cheryl (Committee member) / Sweazea, Karen (Committee member) / Vaughan, Linda (Committee member) / Arizona State University (Publisher)
Created2014
Description
ABSTRACT
Asthma is a high-stress, chronic medical condition; 1 in 12 adults in the United States combat the bronchoconstriction from asthma. However, there are very few strong studies indicating any alternative therapy for asthmatics, particularly following a cold incidence. Vitamin C has been proven to be effective for other high-stress populations, but the asthmatic population has not yet been trialed. This study examined the effectiveness of vitamin C supplementation during the cold season on cold incidence and asthmatic symptoms. Asthmatics, otherwise-healthy, who were non-smokers and non-athletes between the ages of 18 and 55 with low plasma vitamin C concentrations were separated by anthropometrics and vitamin C status into two groups: either vitamin C (500 mg vitamin C capsule consumed twice per day) or control (placebo capsule consumed twice per day). Subjects were instructed to complete the Wisconsin Upper Respiratory Symptom Survey-21 and a short asthma symptoms questionnaire daily along with a shortened vitamin C Food Frequency Questionnaire and physical activity questionnaire weekly for eight weeks. Blood samples were drawn at Week 0 (baseline), Week 4, and Week 8. Compliance was monitored through a calendar check sheet. The vitamin C levels of both groups increased from Week 0 to Week 4, but decreased in the vitamin C group at Week 8. The vitamin C group had a 19% decrease in plasma histamine while the control group had a 53% increase in plasma histamine at the end of the trial, but this was not statistically significant (p>0.05). Total symptoms recorded from WURSS-21 were 129.3±120.7 for the vitamin C and 271.0±293.9, but the difference was not statistically significant (p=0.724). Total asthma symptoms also slightly varied between the groups, but again was not statistically significant (p=0.154). These results were hindered by the low number of subjects recruited. Continued research in this study approach is necessary to definitively reject or accept the potential role of vitamin C in asthma and cold care.
Asthma is a high-stress, chronic medical condition; 1 in 12 adults in the United States combat the bronchoconstriction from asthma. However, there are very few strong studies indicating any alternative therapy for asthmatics, particularly following a cold incidence. Vitamin C has been proven to be effective for other high-stress populations, but the asthmatic population has not yet been trialed. This study examined the effectiveness of vitamin C supplementation during the cold season on cold incidence and asthmatic symptoms. Asthmatics, otherwise-healthy, who were non-smokers and non-athletes between the ages of 18 and 55 with low plasma vitamin C concentrations were separated by anthropometrics and vitamin C status into two groups: either vitamin C (500 mg vitamin C capsule consumed twice per day) or control (placebo capsule consumed twice per day). Subjects were instructed to complete the Wisconsin Upper Respiratory Symptom Survey-21 and a short asthma symptoms questionnaire daily along with a shortened vitamin C Food Frequency Questionnaire and physical activity questionnaire weekly for eight weeks. Blood samples were drawn at Week 0 (baseline), Week 4, and Week 8. Compliance was monitored through a calendar check sheet. The vitamin C levels of both groups increased from Week 0 to Week 4, but decreased in the vitamin C group at Week 8. The vitamin C group had a 19% decrease in plasma histamine while the control group had a 53% increase in plasma histamine at the end of the trial, but this was not statistically significant (p>0.05). Total symptoms recorded from WURSS-21 were 129.3±120.7 for the vitamin C and 271.0±293.9, but the difference was not statistically significant (p=0.724). Total asthma symptoms also slightly varied between the groups, but again was not statistically significant (p=0.154). These results were hindered by the low number of subjects recruited. Continued research in this study approach is necessary to definitively reject or accept the potential role of vitamin C in asthma and cold care.
ContributorsEarhart, Kathryn Michelle (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2015
Description
For animals that experience annual cycles of gonad development, the seasonal timing (phenology) of gonad growth is a major adaptation to local environmental conditions. To optimally time seasonal gonad growth, animals use environmental cues that forecast future conditions. The availability of food is one such environmental cue. Although the importance of food availability has been appreciated for decades, the physiological mechanisms underlying the modulation of seasonal gonad growth by this environmental factor remain poorly understood.
Urbanization is characterized by profound environmental changes, and urban animals must adjust to an environment vastly different from that of their non-urban conspecifics. Evidence suggests that birds adjust to urban areas by advancing the timing of seasonal breeding and gonad development, compared to their non-urban conspecifics. A leading hypothesis to account for this phenomenon is that food availability is elevated in urban areas, which improves the energetic status of urban birds and enables them to initiate gonad development earlier than their non-urban conspecifics. However, this hypothesis remains largely untested.
My dissertation dovetailed comparative studies and experimental approaches conducted in field and captive settings to examine the physiological mechanisms by which food availability modulates gonad growth and to investigate whether elevated food availability in urban areas advances the phenology of gonad growth in urban birds. My captive study demonstrated that energetic status modulates reproductive hormone secretion, but not gonad growth. By contrast, free-ranging urban and non-urban birds did not differ in energetic status or plasma levels of reproductive hormones either in years in which urban birds had advanced phenology of gonad growth or in a year that had no habitat-related disparity in seasonal gonad growth. Therefore, my dissertation provides no support for the hypothesis that urban birds begin seasonal gonad growth because they are in better energetic status and increase the secretion of reproductive hormones earlier than non-urban birds. My studies do suggest, however, that the phenology of key food items and the endocrine responsiveness of the reproductive system may contribute to habitat-related disparities in the phenology of gonad growth.
Urbanization is characterized by profound environmental changes, and urban animals must adjust to an environment vastly different from that of their non-urban conspecifics. Evidence suggests that birds adjust to urban areas by advancing the timing of seasonal breeding and gonad development, compared to their non-urban conspecifics. A leading hypothesis to account for this phenomenon is that food availability is elevated in urban areas, which improves the energetic status of urban birds and enables them to initiate gonad development earlier than their non-urban conspecifics. However, this hypothesis remains largely untested.
My dissertation dovetailed comparative studies and experimental approaches conducted in field and captive settings to examine the physiological mechanisms by which food availability modulates gonad growth and to investigate whether elevated food availability in urban areas advances the phenology of gonad growth in urban birds. My captive study demonstrated that energetic status modulates reproductive hormone secretion, but not gonad growth. By contrast, free-ranging urban and non-urban birds did not differ in energetic status or plasma levels of reproductive hormones either in years in which urban birds had advanced phenology of gonad growth or in a year that had no habitat-related disparity in seasonal gonad growth. Therefore, my dissertation provides no support for the hypothesis that urban birds begin seasonal gonad growth because they are in better energetic status and increase the secretion of reproductive hormones earlier than non-urban birds. My studies do suggest, however, that the phenology of key food items and the endocrine responsiveness of the reproductive system may contribute to habitat-related disparities in the phenology of gonad growth.
ContributorsDavies, Scott (Author) / Deviche, Pierre (Thesis advisor) / Sweazea, Karen (Committee member) / McGraw, Kevin (Committee member) / Orchinik, Miles (Committee member) / Warren, Paige (Committee member) / Arizona State University (Publisher)
Created2014
Description
The common cold is a significant cause of morbidity world-wide, with human rhinovirus infections accounting for a majority colds suffered each year. While the symptoms of the common cold are generally mild and self-limiting, vulnerable populations such as individuals with asthma can experience severe secondary complications including acute asthma exacerbation which can result in severe morbidity. Most human rhinovirus types utilize Intercellular Adhesion Molecule-1 (ICAM-1) as a receptor to enter cells and initiate infection. Expression of this cell-surface protein is elevated in the respiratory tract of asthma patients. The theoretical basis for this research is the observation that plasma measures of the soluble form of Intercellular Adhesion Molecule-1 (sICAM-1) decrease in response to vitamin C supplementation. As rhinovirus infection occurs in the upper respiratory tract, the primary aim of this study was to evaluate change in sICAM-1 concentration in nasal lavage of asthmatic individuals in response to vitamin C supplementation. Otherwise healthy asthmatic adults between the ages of 18-65 years who were not currently using steroidal nasal sprays, smoking, or actively training for competitive sports were recruited from a university community and surrounding area to participate in an 18-day double-blind randomized placebo-controlled supplement study with a parallel arm design. 13 subjects were stratified based on age, gender, BMI and baseline plasma vitamin C level to receive either 500 mg vitamin C twice daily (VTC, n=7) or placebo (PLC, n=6). Biochemical measures included nasal lavage sICAM-1, plasma sICAM-1, plasma histamine, and plasma vitamin C. Survey measures included Wisconsin Upper Respiratory Symptom Survey-21 to assess colds, Daytime Symptom Diary Scale to assess asthma symptoms, and measures of diet quality including a vitamin C food frequency questionnaire and Rapid Eating Assessment for Participants. No between group comparison of means reached significance (Mann-Whitney U test, p>0.05). Nasal lavage sICAM-1 levels were decreased in VTC group by 37% at study day 4, although this finding did not reach significance. Findings in this study can be used to develop future investigations into the response of nasal lavage sICAM-1 to vitamin C supplementation.
ContributorsGnant, Lindsay (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Chang, Yung (Committee member) / Arizona State University (Publisher)
Created2014
Description
The ability to shift the photovoltaic (PV) power curve and make the energy accessible during peak hours can be accomplished through pairing solar PV with energy storage technologies. A prototype hybrid air conditioning system (HACS), built under supervision of project head Patrick Phelan, consists of PV modules running a DC compressor that operates a conventional HVAC system paired with a second evaporator submerged within a thermal storage tank. The thermal storage is a 0.284m3 or 75 gallon freezer filled with Cryogel balls, submerged in a weak glycol solution. It is paired with its own separate air handler, circulating the glycol solution. The refrigerant flow is controlled by solenoid valves that are electrically connected to a high and low temperature thermostat. During daylight hours, the PV modules run the DC compressor. The refrigerant flow is directed to the conventional HVAC air handler when cooling is needed. Once the desired room temperature is met, refrigerant flow is diverted to the thermal storage, storing excess PV power. During peak energy demand hours, the system uses only small amounts of grid power to pump the glycol solution through the air handler (note the compressor is off), allowing for money and energy savings. The conventional HVAC unit can be scaled down, since during times of large cooling demands the glycol air handler can be operated in parallel with the conventional HVAC unit. Four major test scenarios were drawn up in order to fully comprehend the performance characteristics of the HACS. Upon initial running of the system, ice was produced and the thermal storage was charged. A simple test run consisting of discharging the thermal storage, initially ~¼ frozen, was performed. The glycol air handler ran for 6 hours and the initial cooling power was 4.5 kW. This initial test was significant, since greater than 3.5 kW of cooling power was produced for 3 hours, thus demonstrating the concept of energy storage and recovery.
ContributorsPeyton-Levine, Tobin (Author) / Phelan, Patrick (Thesis advisor) / Trimble, Steve (Committee member) / Wang, Robert (Committee member) / Arizona State University (Publisher)
Created2012
Description
While exercising mammalian muscle increasingly relies on carbohydrates for fuel as aerobic exercise intensity rises above the moderate range, flying birds are extraordinary endurance athletes and fuel flight, a moderate-high intensity exercise, almost exclusively with lipid. In addition, Aves have long lifespans compared to weight-matched mammals. As skeletal muscle mitochondria account for the majority of oxygen consumption during aerobic exercise, the primary goal was to investigate differences in isolated muscle mitochondria between these species and to examine to what extent factors intrinsic to mitochondria may account for the behavior observed in the intact tissue and whole organism. First, maximal enzyme activities were assessed in sparrow and rat mitochondria. Citrate synthase and aspartate aminotransferase activity were higher in sparrow compared to rat mitochondria, while glutamate dehydrogenase activity was lower. Sparrow mitochondrial NAD-linked isocitrate dehydrogenase activity was dependent on phosphate, unlike the mammalian enzyme. Next, the rate of oxygen consumption (JO), electron transport chain (ETC) activity, and reactive oxygen species (ROS) production were assessed in intact mitochondria. Maximal rates of fat oxidation were lower than for carbohydrate in rat but not sparrow mitochondria. ETC activity was higher in sparrows, but no differences were found in ROS production between species. Finally, fuel selection and control of respiration at three rates between rest and maximum were assessed. Mitochondrial fuel oxidation and selection mirrored that of the whole body; in rat mitochondria the reliance on carbohydrate increased as the rate of oxygen consumption increased, whereas fat dominated under all conditions in the sparrow. These data indicate fuel selection, at least in part, can be modulated at the level of the mitochondrial matrix when multiple substrates are present at saturating levels. As an increase in matrix oxidation-reduction potential has been linked to a suppression of fat oxidation and high ROS production, the high ETC activity relative to dehydrogenase activity in avian compared to mammalian mitochondria may result in lower matrix oxidation-reduction potential, allowing fatty acid oxidation to proceed while also resulting in low ROS production in vivo.
ContributorsKuzmiak, Sarah (Author) / Willis, Wayne T (Thesis advisor) / Mandarino, Lawrence (Committee member) / Sweazea, Karen (Committee member) / Harrison, Jon (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
The study of high energy particle irradiation effect on Josephson junction tri-layers is relevant to applications in space and radioactive environments. It also allows us to investigate the influence of defects and interfacial intermixing on the junction electrical characteristics. In this work, we studied the influence of 2MeV Helium ion irradiation with doses up to 5.2×1016 ions/cm2 on the tunneling behavior of Nb/Al/AlOx/Nb Josephson junctions. Structural and analytical TEM characterization, combined with SRIM modeling, indicates that over 4nm of intermixing occurred at the interfaces. EDX analysis after irradiation, suggests that the Al and O compositions from the barrier are collectively distributed together over a few nanometers. Surprisingly, the IV characteristics were largely unchanged. The normal resistance, Rn, increased slightly (<20%) after the initial dose of 3.5×1015 ions/cm2 and remained constant after that. This suggests that tunnel barrier electrical properties were not affected much, despite the significant changes in the chemical distribution of the barrier's Al and O shown in SRIM modeling and TEM pictures. The onset of quasi-particle current, sum of energy gaps (2Δ), dropped systematically from 2.8meV to 2.6meV with increasing dosage. Similarly, the temperature onset of the Josephson current dropped from 9.2K to 9.0K. This suggests that the order parameter at the barrier interface has decreased as a result of a reduced mean free path in the Al proximity layer and a reduction in the transition temperature of the Nb electrode near the barrier. The dependence of Josephson current on the magnetic field and temperature does not change significantly with irradiation, suggesting that intermixing into the Nb electrode is significantly less than the penetration depth.
ContributorsZhang, Tiantian (Author) / Newman, Nathan (Thesis advisor) / Rowell, John M (Committee member) / Singh, Rakesh K. (Committee member) / Chamberlin, Ralph (Committee member) / Wang, Robert (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT This randomized, controlled, double-blind crossover study examined the effects of a preprandial, 20g oral dose of apple cider vinegar (ACV) on colonic fermentation and glycemia in a normal population, with the ultimate intention of identifying the mechanisms by which vinegar has been shown to reduce postprandial glycemia and insulinemia. Fifteen male and female subjects were recruited, ages 20-60y, who had no prior history of gastrointestinal (GI) disease or resections impacting normal GI function, were non-smokers, were non-vegetarian/vegan, were not taking any medications known to alter (glucose) metabolism, and were free of chronic disease including diabetes. Subjects were instructed to avoid exercise, alcohol and smoking the day prior to their trials and to consume a standardized, high-carbohydrate dinner meal the eve prior. There was a one-week washout period per subject between appointments. Breath hydrogen, serum insulin and capillary glucose were assessed over 3 hours after a high-starch breakfast meal to evaluate the impact of preprandial supplementation with ACV or placebo (water). Findings confirmed the antiglycemic effects of ACV as documented in previous studies, with significantly lower mean blood glucose concentrations observed during ACV treatment compared to the placebo at 30 min (p=0.003) and 60 min (p=0.005), and significantly higher mean blood glucose concentrations at 180 min (p=0.045) postprandial. No significant differences in insulin concentrations between treatments. No significant differences were found between treatments (p>0.05) for breath hydrogen; however, a trend was observed between the treatments at 180 min postprandial where breath hydrogen concentration was visually perceived as being higher with ACV treatment compared to the placebo. Therefore, this study failed to support the hypothesis that preprandial ACV ingestion produces a higher rate of colonic fermentation within a 3 hour time period following a high-carbohydrate meal. Due to variations in experiment duration noted in other literature, an additional study of similar nature with an expanded specimen collections period, well beyond 3 hours, is warranted.
ContributorsMedved, Emily M (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2012