Matching Items (130)
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
This study confirms that there is stigma attached to how Somali-Americans perceive mental and emotional impairments compared to the perception of physical disabilities and impairments. More Somali-Americans are willing to seek help regarding their mental and physical health which is a positive step in improving the perceptions of Somali-Americans towards mental or emotional impairments and physical disabilities. Findings can contribute to the knowledge of health care professionals (i.e. nurses) in caring for patients identifying as Somali to promote culturally competent care.
ContributorsAden, Amina (Author) / Hosley, Brenda (Thesis director) / Lee, Rebecca (Committee member) / Lyles, Annmarie (Committee member) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Research supports that music therapy can be used in multiple aspects of care for patients living within different environments. There is a gap in the literature when it comes to the impact of music sessions for older adults who do not have a diagnosed disease, therefore this study analyzes this population specifically. This study examines music therapy and its effects on anxiety and depression in adults aged 65 or older living in independent living homes. The adults participated in a mixed-methods study over the span of one month examining music as an intervention to decrease anxiety and depression. Each subject consented into the study, completed a demographic survey, answered open-ended questions regarding their experience with anxiety/sadness and ways to cope, as well as Profile of Moods Scale (POMS) during the first session. On the last week of the study, the participants were asked to fill out the same POMS scale to evaluate whether music influenced anxiety and depression. There was limited evidence found in this study to support the use of music therapy as an intervention to decrease anxiety and depression in adults over the age of 65.
ContributorsWolfus, Sarah Ilyssa (Author) / Lee, Rebecca (Thesis director) / Larkey, Linda (Committee member) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The Centers for Disease Control and Prevention in the United States announced that there has been roughly a 50% increase in the prevalence of food allergies among people between the years of 1997 - 2011. A food allergy can be described as a medical condition where being exposed to a certain food triggers a harmful immune response in the body, known as an allergic reaction. These reactions can range from mild to fatal, and they are caused mainly by the top 8 major food allergens: dairy, eggs, peanuts, tree nuts, wheat, soy, fish, and shellfish. Food allergies mainly plague children under the age of 3, as some of them will grow out of their allergy sensitivity over time, and most people develop their allergies at a young age, and not when they are older. The rise in prevalence is becoming a frightening problem around the world, and there are emerging theories that are attempting to ascribe a cause. There are three well-known hypotheses that will be discussed: the Hygiene Hypothesis, the Dual-Allergen Exposure Hypothesis, and the Vitamin-D Deficiency Hypothesis. Beyond that, this report proposes that a new hypothesis be studied, the Food Systems Hypothesis. This hypothesis theorizes that the cause of the rise of food allergies is actually caused by changes in the food itself and particularly the pesticides that are used to cultivate it.
ContributorsCromer, Kelly (Author) / Lee, Rebecca (Thesis director) / MacFadyen, Joshua (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Hematopoietic stem cell transplantation (HSCT) is a unique but intense procedure used to save the lives of patients with hematopoietic malignancies. However, patients and caregivers undergoing HSCT can experience prolonged psychological distress due to an intense and distinctive transplant process. Types of psychological distress include anxiety, depression, social isolation, and post-traumatic stress disorder. Although this a significant healthcare problem, limited research has been conducted within the HSCT patient and caregiver population to investigate ways to improve their mental health. The purpose of this study was to examine the effects of an educational video intervention about post-transplant recovery in decreasing emotional distress and promoting emotional well-being in HSCT patients and caregivers. This pilot study utilized a quantitative single-group pretest-posttest design to examine the effect of educational videos on participant's emotional well-being. Four educational videos were developed using information gathered from several reliable bone marrow transplant and cancer websites. A convenience sampling method was used to recruit HSCT patient and caregiver participants. Eleven Caucasian, English-speaking individuals (6 patients, 5 caregivers; 54.5% female; M age= 43.7 years) across the United States were enrolled in the 60-90 minute online intervention. Participant responses were measured using pretest and posttest questionnaires. Results from the study found that the educational videos were effective in decreasing levels of depression and anxiety. Implications for nursing practice include the need to educate HSCT patients and caregivers about transplant recovery to decrease emotional distress. This study demonstrates the impact post-transplant education has on decreasing depression and anxiety in HSCT patients and caregivers.
ContributorsBosselman, Kate Elizabeth (Author) / Kim, Sunny (Thesis director) / Lee, Rebecca (Committee member) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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
Microfluidic platforms have been exploited extensively as a tool for the separation of particles by electric field manipulation. Microfluidic devices can facilitate the manipulation of particles by dielectrophoresis. Separation of particles by size and type has been demonstrated by insulator-based dielectrophoresis in a microfluidic device. Thus, manipulating particles by size has been widely studied throughout the years. It has been shown that size-heterogeneity in organelles has been linked to multiple diseases from abnormal organelle size. Here, a mixture of two sizes of polystyrene beads (0.28 and 0.87 μm) was separated by a ratchet migration mechanism under a continuous flow (20 nL/min). Furthermore, to achieve high-throughput separation, different ratchet devices were designed to achieve high-volume separation. Recently, enormous efforts have been made to manipulate small size DNA and proteins. Here, a microfluidic device comprising of multiple valves acting as insulating constrictions when a potential is applied is presented. The tunability of the electric field gradient is evaluated by a COMSOL model, indicating that high electric field gradients can be reached by deflecting the valve at a certain distance. Experimentally, the tunability of the dynamic constriction was demonstrated by conducting a pressure study to estimate the gap distance between the valve and the substrate at different applied pressures. Finally, as a proof of principle, 0.87 μm polystyrene beads were manipulated by dielectrophoresis. These microfluidic platforms will aid in the understanding of size-heterogeneity of organelles for biomolecular assessment and achieve separation of nanometer-size DNA and proteins by dielectrophoresis.
ContributorsOrtiz, Ricardo (Author) / Ros, Alexandra (Thesis advisor) / Hayes, Mark (Committee member) / Borges, Chad (Committee member) / Arizona State University (Publisher)
Created2021
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
Description
Microfluidics has enabled many biological and biochemical applications such as high-throughput drug testing or point-of-care diagnostics. Dielectrophoresis (DEP) has recently achieved prominence as a powerful microfluidic technique for nanoparticle separation. Novel electric field-assisted insulator-based dielectrophoresis (iDEP) microfluidic devices have been employed to fractionate rod-shaped nanoparticles like Single-walled carbon nanotubes (SWNTs) and manipulate biomolecules like Deoxyribonucleic acid (DNA) and proteins. This dissertation involves the development of traditional as well as 3D-printed iDEP devices for the manipulation of nm-to-µm scale analytes. First, novel iDEP microfluidic constriction-based sorting devices were developed to introduce inhomogeneous electric field gradients to fractionate SWNTs by length. SWNTs possess length-specific optical and electrical properties, expanding their potential applications for future nanoscale devices. Standard synthesis procedures yield SWNTs in large-length polydispersity and chirality. Thus, an iDEP-based fractionation tool for desired lengths of SWNTs may be beneficial. This dissertation presents the first study of DEP characterization and fractionation of SWNTs using an iDEP microfluidic device. Using this iDEP constriction sorter device, two different length distributions of SWNTs were sorted with a sorting efficiency of >90%. This study provides the fundamentals of fractionating SWNTs by length, which can help separate and purify SWNTs for future nanoscale-based applications. Manipulation of nm-scale analytes requires achieving high electric field gradients in an iDEP microfluidic device, posing one of the significant challenges for DEP applications. Introducing nm-sized constrictions in an iDEP device can help generate a higher electric field gradient. However, this requires cumbersome and expensive fabrication methods. In recent years, 3D printing has drawn tremendous attention in microfluidics, alleviating complications associated with complex fabrication methods. A high-resolution 3D-printed iDEP device was developed and fabricated for iDEP-based manipulation of analytes. A completely 3D-printed device with 2 µm post-gaps was realized, and fluorescent polystyrene (PS) beads, λ-DNA, and phycocyanin protein trapping were demonstrated. Furthermore, a nm-resolution 3D-printed iDEP device was successfully printed. In the future, these high-resolution 3D-printed devices may lead to exploring DEP characteristics of nanoscale analytes like single protein molecules and viruses. The electric field-assisted unique fractionation phenomena in microfluidic platforms will become a critical solution for nanoparticle separation and manipulating biomolecules.
ContributorsRabbani, Mohammad Towshif (Author) / Ros, Alexandra (Thesis advisor) / Stephanopoulos, Nicholas (Committee member) / Buttry, Daniel (Committee member) / Arizona State University (Publisher)
Created2022