Matching Items (93)
Description
Nonalcoholic fatty liver disease is the most common form of chronic liver disease in the United States. Diets high in saturated fats are known to promote obesity and hepatic steatosis. The consumption of a high fat diet (HFD) can increase the risk factors associated with insulin resistance, which can lead to the onset of diabetes and obesity. A prior study of a soil-derived organometallic complex (OMC) showed that supplementation reduces glucose and body mass in diabetic mice. The goal of this study was to test the efficacy of a similar OMC compound on the mitigation of hepatic steatosis induced from a HFD. Six-week-old male Sprague-Dawley rats (n=42) were divided into the following diet groups: standard rodent chow or 60% kcal from fat high fat diet (mainly lard) for 10-weeks. Rats were further divided into OMC treatment groups with OMC added to their drinking water: 0 mg/ml, 0.6 mg/ml or 3.0mg/ml OMC. At 10 weeks, study animals were euthanized with sodium pentobarbital (200 mg/kg, i.p.) and cardiac plasma as well as liver samples were collected and stored at -80° C until further analyses. Plasma ALT and AST as well as liver triglyceride and free glycerol concentrations were measured using commercially available kits. To assess cellular injury, aspartate transaminase (AST; released mainly from injured cardiac and liver cells) and alanine transaminase (ALT; released mainly from injured liver cells) were examined. Rats fed HFD had elevated plasma ALT activity, which was prevented by treatment with the high dose of OMC (p<0.05). No changes in plasma AST activity were detected. Examination of liver triglyceride and free glycerol concentrations showed increased fat accumulation in the liver of rats consuming HFD (Two-Way ANOVA, p<0.001). OMC did not prevent this increase. These findings suggest that, although OMC does not prevent the accumulation of lipids in the liver of rats fed HFD, it does mitigate liver injury resulting from excess dietary intake of saturated fats.
ContributorsWood, Courtney Ann (Author) / Sweazea, Karen (Thesis director) / Shaibi, Gabriel (Committee member) / Johnston, Carol (Committee member) / School of Art (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
To determine whether a 3-month lifestyle intervention could increase social support (SS) and physical activity (PA) in Latino adolescents with obesity. Participants in the intervention will increase (SS) from family and friends and PA. Youth attended weekly nutritional and exercise sessions at the YMCA. Familial and Friend SS for PA is not significant; moderate to vigorous PA is significant. Culturally-grounded & community-based intervention leads to changes in SS for PA and PA in Latino adolescents.
ContributorsMartin, Dwayne Jeffery (Author) / Shaibi, Gabriel (Thesis director) / Williams, Allison (Committee member) / School of Human Evolution & Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
My aims with this research project were to conduct a network analysis on collaborators in the ¡Viva Maryvale! project, a diabetes prevention program in Maryvale, AZ. The goals of the social network analysis were to measure the connections that collaborating organizations have to each other, the strength of these connections, and the activities that connected organizations collaborate on. I hypothesized that performing a network analysis would inform me of the strengths and weaknesses of the ¡Viva Maryvale! project in order to advise the next steps of a targeted approach to diabetes prevention among vulnerable populations, thus affecting public health outcomes in the greater Phoenix Valley.
ContributorsKellog, Anna (Author) / Shaibi, Gabriel (Thesis director) / Soltero, Erica (Committee member) / School of Public Affairs (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Finding life beyond Earth could change our understanding of life and habitability. The best place to look for life beyond Earth is Jupiter's moon, Europa. It has been estimated Europa may have a liquid, salt-water subsurface with 2 to 3 times the volume of all Earth's oceans. Knowing that all life requires water, it is in our best interest to explore Europa. This thesis explored the plausibility of life on Europa in four of its environments: on the surface, under the ice shell, in the liquid subsurface, and at the bottom of the liquid subsurface. Each of these environments were defined from science literature and compared to known Earth analogs. Europa's surface is not likely to support life, as there is not liquid water present. There is also extremely high radiation bombardment and extremely low surface temperatures that are estimated to be well out of the range for supporting life. It is more plausible that life could be under Europa's ice shell than on the surface. Under the surface, radiation exposure dramatically reduces. Researchers have found organisms on Earth that can live in similar environments as Europa's ice as well. These organisms require some interaction with liquid water though. Uncertainties about Europa's ice shell thickness and radiation load per depth it experiences, as well as there being limited research on organisms in ice environments, hinder us from definitively assessing the plausibility of life under the surface. The best environment on Europa to look for life on Europa is the subsurface. There remain a lot of uncertainties about the subsurface, however, that make it difficult to assess the plausibility of finding life. These uncertainties include its depth, water activity, salinity, temperature, pressure, and structure. This subsurface may be suitable for life, but until we can further understand the environment of the subsurface, we cannot make definite conclusions. As for assessing the plausibility of life at the bottom of Europa's subsurface, there is not much we know about this environment either. It has been suggested there may be hydrothermal vents, but no evidence has either supported or rejected this idea. Without a clear understanding of the environment at the bottom of the subsurface, the plausibility of life here cannot be definitively answered. It is apparent we need to further study Europa. In particular, we need to focus on understanding the subsurface. When the subsurface is better defined, we can better assess the plausibility of life being present. Fortunately, both NASA and the ESA are currently planning missions to Europa that are scheduled to launch in the 2020s.
ContributorsHoward, Cheyenne Whiffen (Author) / Farmer, Jack (Thesis director) / Shock, Everett (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Background: The prevalence of childhood obesity has disproportionately affected Latino youth and can be seen with an increase incidence of Type 2 Diabetes. This increase in obesity can be attributed to physical inactivity. Increases in social support and self-efficacy are independently related to increases in physical activity. A lifestyle intervention can lead to increases in social support, self-efficacy and physical activity. Objective/Hypothesis: The objective of this study was to determine whether a 12-week lifestyle intervention could increase social support, self-efficacy and physical activity in obese Latino adolescents that participated in the intervention. It was hypothesized that adolescents that participated in the intervention would increase self-efficacy, social support from family and friends, and physical activity compared to their control counterparts. Study Design/Participants: In a randomized control trial, there were 125 Latino (n= 60 experimental group; n= 65 control group; mean age = 15.17 +- 1.65 Males n = 60; n = 65 females) participants included in this study. Participants were also required to have a BMI percentile >= 95th percentile for age and gender or BMI >= 30 kg/m2. Methods: The intervention, which was developed using the Social Cognitive Theory had components focusing on social support and self-efficacy and also consisted of nutrition education classes and physical activity sessions for 12 weeks. The psychosocial constructs of self-efficacy and social support were measured using the Adolescent Self-Efficacy for Diet and Activity Behaviors and Adolescent Social Support for Diet and Exercise Survey, respectively. Physical activity was assessed by the 3-day Physical Activity Recall. Results: We found significant increases in social support in family (p = 0.042) and vigorous physical activity (p = 0.001). There was also a significant difference between control and treatment group for moderate to vigorous physical activity after the intervention (p = 0.027). There were no changes in social support from friends or self-efficacy. Conclusion: We concluded that a 12-week lifestyle intervention did lead to changes in social support and physical activity behaviors. These changes could have been influenced by the intervention as they were measured these constructs pre/post intervention.
ContributorsRahman, Hanna (Author) / Shaibi, Gabriel (Thesis director) / Hoffner, Kristin (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The purpose of this study was to examine the association between VLDL and diabetes risk factors, and the impact of a lifestyle intervention on VLDL levels in obese Latino youth. Participants (N=160) in this study were taken from a lager diabetes prevention program for Latino adolescents (Age=14.8±0.8 years, BMI=98.2±1.4). Youth participated in a 12-week lifestyle intervention that included physical activity (60 minutes, 3x/week) and nutrition education sessions (60 minutes, 1x/week) that were delivered to families at the downtown Phoenix YMCA. Primary outcomes included VLDL and diabetes risk factors including fasting and 2-hour glucose and insulin which were measured at baseline and 12-weeks post-intervention. Baseline VLDL levels were significantly correlated with fasting insulin (r =.270, P<0.01) and youth who were more insulin resistant displayed higher VLDL levels compared to youth who were less insulin resistant derived from fasting insulin levels (M=29.8±14.7 mg/dl vs. M=21.6±9.6 mg/dl, P<0.01). In total, 77 participants completed the lifestyle intervention. At post-intervention, VLDL levels were significantly reduced (M=26.0±13.3 mg/dl to M=23.3±11.6 mg/dl, P=0.02). Culturally-grounded, community-based, family-focused lifestyle interventions are a promising approach for reducing cardiovascular disease risk factors in high-risk youth at risk for diabetes.
ContributorsNavabi, Neeku Ariana (Author) / Shaibi, Gabriel (Thesis director) / Soltero, Erica (Committee member) / Ryder, Justin (Committee member) / School of Nutrition and Health Promotion (Contributor) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Yellowstone National Park has a vibrant variety of flora, fauna, and hydrothermal systems all collected together in one large and complex system. Studies have been conducted for at least several decades in order to make sense of this system in ways that may be relevant to other similar geologies around the world. The latest update in this ever-ongoing study involves the collection and analysis of water samples from 2016. These samples have been analyzed for conductivity, pH, temperature, dissolved organic carbon, dissolved inorganic carbon, carbon isotopes, dissolved oxygen, ferrous iron, sulfide, silica, and more. While not many trends were found in this data in regards to dissolved organic carbon values, this is a substantial addition to a growing body of information that could yield more impressive information in times to come. In addition, factors that have yet to analyzed for this 2016 data, such as concentrations of metals and metalloids, may provide some insights when put through a chloride vs sulfate framework to separate out different reaction regions.
ContributorsDoan, Cuong Le (Author) / Shock, Everett (Thesis director) / Gould, Ian (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Obesity and related health disparities including type 2 diabetes disproportionately impact Latino youth. These health disparities may be the result of gene-environment interactions, but limited research has examined these interactions in the pediatric age group. Lifestyle intervention is the cornerstone for preventing diabetes among high-risk populations and epigenetic and genetic factors may help explain the biological mechanisms underlying diabetes risk reduction following lifestyle changes. MicroRNAs (miRNAs) are small, non-coding RNA’s that regulate gene expression and have emerged as potential biomarkers for predicting type 2 diabetes risk in adults but have yet to be applied to youth. Therefore, the purpose of this study was to identify changes in miRNA expression among Latino youth with prediabetes (4 female/2 male, ages 14-16, BMI percentile 99 ±.2) who participated in a 12-week lifestyle intervention focused on increasing physical activity and improving nutrition-related behaviors.
ContributorsKarch, Jamie (Co-author) / Day, Samantha (Co-author) / Shaibi, Gabriel (Thesis director) / Coletta, Dawn (Committee member) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
The ability to find evidence of life on early Earth and other planets is constrained by the current understanding of biosignatures and our ability to differentiate fossils from abiotic mimics. When organisms transition from the living realm to the fossil record, their morphological and chemical characteristics are modified, usually resulting in the loss of information. These modifications can happen during early and late diagenesis and differ depending on local geochemical properties. These post-depositional modifications need to be understood to better interpret the fossil record. Siliceous hot spring deposits (sinters) are of particular interest for biosignature research as they are early Earth analog environments and targets for investigating the presence of fossil life on Mars. As silica-supersaturated fluids flow from the vent to the distal apron, they precipitate non-crystalline opal-A that fossilizes microbial communities at a range in scales (μm-cm). Therefore, many studies have documented the ties between the active microbial communities and the morphological and chemical biosignatures in hot springs. However, far less attention has been placed on understanding preservation in systems with complex mineralogy or how post-depositional alteration affects the retention of biosignatures. Without this context, it can be challenging to recognize biosignatures in ancient rocks. This dissertation research aims to refine our current understanding of biosignature preservation and retention in sinters. Biosignatures of interest include organic matter, microfossils, and biofabrics. The complex nature of hot springs requires a comprehensive understanding of biosignature preservation that is representative of variable chemistries and post-depositional alterations. For this reason, this dissertation research chapters are field site-based. Chapter 2 investigates biosignature preservation in an unusual spring with mixed opal-A-calcite mineralogy at Lýsuhóll, Iceland. Chapter 3 tracks how silica diagenesis modifies microfossil morphology and associated organic matter at Puchuldiza, Chile. Chapter 4 studies the effects of acid fumarolic overprinting on biosignatures in Gunnuhver, Iceland. To accomplish this, traditional geologic methods (mapping, petrography, X-ray diffraction, bulk elemental analyses) were combined with high-spatial-resolution elemental mapping to better understand diagenetic effects in these systems. Preservation models were developed to predict the types and styles of biosignatures that can be present depending on the depositional and geochemical context. Recommendations are also made for the types of deposits that are most likely to preserve biosignatures.
ContributorsJuarez Rivera, Marisol (Author) / Farmer, Jack D (Thesis advisor) / Hartnett, Hilairy E (Committee member) / Shock, Everett (Committee member) / Garcia-Pichel, Ferran (Committee member) / Trembath-Reichert, Elizabeth (Committee member) / Arizona State University (Publisher)
Created2021
Description
I present results of field and laboratory experiments investigating the habitability of one of Earth’s driest environments: the Atacama Desert. This Desert, along the west coast of South America spanning Perú and Chile, is one of the driest places on Earth and has been exceedingly arid for millions of years. These conditions create the perfect natural laboratory for assessing life at the extremes of habitability. All known life needs water; however, the extraordinarily dry Atacama Desert is inhabited by well-adapted microorganisms capable of colonizing this hostile environment. I show field and laboratory evidence of an environmental process, water vapor adsorption, that provides a daily, sustainable input of water into the near (3 - 5 cm) subsurface through water vapor-soil particle interactions. I estimate that this water input may rival the yearly average input of rain in these soils (~2 mm).
I also demonstrate, for the first time, that water vapor adsorption is dependent on mineral composition via a series of laboratory water vapor adsorption experiments. The results of these experiments provide evidence that mineral composition, and ultimately soil composition, measurably and significantly affect the equilibrium soil water content. This suggests that soil microbial communities may be extremely heterogeneous in distribution depending on the distribution of adsorbent minerals.
Finally, I present changes in biologically relevant gasses (i.e., H2, CH4, CO, and CO2) over long-duration incubation experiments designed to assess the potential for biological activity in soils collected from a hyperarid region in the Atacama Desert. These long-duration experiments mimicked typical water availability conditions in the Atacama Desert; in other words, the incubations were performed without condensed water addition. The results suggest a potential for methane-production in the live experiments relative to the sterile controls, and thus, for biological activity in hyperarid soils. However, due to the extremely low biomass and extremely low rates of activity in these soils, the methods employed here were unable to provide robust evidence for activity. Overall, the hyperarid regions of the Atacama Desert are an important resource for researchers by providing a window into the environmental dynamics and subsequent microbial responses near the limit of habitability.
ContributorsGlaser, Donald M (Author) / Hartnett, Hilairy E (Thesis advisor) / Anbar, Ariel (Committee member) / Shock, Everett (Committee member) / Arizona State University (Publisher)
Created2022