Matching Items (108)
Description
By increasing the mean and variance of environmental temperatures, climate change has caused local extinctions and range shifts of numerous species. However, biologists disagree on which populations and species are most vulnerable to future warming. This debate arises because biologists do not know which physiological processes are most vulnerable to temperature or how to model these processes in complex environments. Using the South American locust (Schistocerca cancellata) as a model system, my dissertation addressed this debate and explained how climate limits the persistence of locust populations. Locusts of S. cancellata are serious agricultural pests with occasional outbreaks covering up to 4 million km2 over six countries. Because outbreaks are largely driven by climate, understanding how climate limits the persistence of locusts may help predict crop losses in future climates. To achieve this aim, I integrated observational, experimental, and computational approaches. First, I tested a physiological model of heat stress. By measuring the heat tolerance of locusts under different oxygen concentrations, I demonstrated that heat tolerance depends on oxygen supply during the hatchling stage only. Second, I modeled the geographic distribution of locusts using physiological traits. I started by measuring thermal effects on consumption and defecation of field-captured locusts, and I then used these data to model energy gain in current and future climates. My results indicated that incorporating physiological mechanisms can improve the accuracy of models and alter predicted impacts of climate change. Finally, I explored the causes and consequences of intraspecific variation in heat tolerance. After measuring heat tolerance of locusts in different hydration states and developmental stages, I modeled survival in historical microclimates. My models indicated that recent climate change has amplified the risk of overheating for locusts, and this risk depended strongly on shade availability, hydration state, and developmental stage. Therefore, the survival of locusts in future climates will likely depend on their access to shade and water. Overall, my dissertation argues that modeling physiological mechanisms can improve the ability of biologists to predict the impacts of climate change.
ContributorsYoungblood, Jacob (Author) / Angilletta, Michael (Thesis advisor) / Buckley, Lauren (Committee member) / Cease, Arianne (Committee member) / Smith, Brian (Committee member) / Vanden Brooks, John (Committee member) / Arizona State University (Publisher)
Created2022
Description
Transorbital surgery has gained recent notoriety due to its incorporation into endoscopic skull base surgery. The body of published literature on the field is cadaveric and observation. The pre-clinical studies are focused on the use of the endoscope only. Furthermore the methodology utilised in the published literature is inconsistent and does not embody the optimal principles of scientific experimentation. This body of work evaluates a minimally invasive novel surgical corridor - the transorbital approach - its validity in neurosurgical practice, as well as both qualitatively and quantitatively assessing available technological advances in a robust experimental fashion. While the endoscope is an established means of visualisation used in clinical transorbital surgery, the microscope has never been assessed with respect to the transorbital approach. This question is investigated here and the anatomical and surgical benefits and limitations of microscopic visualisation demonstrated. The comparative studies provide increased knowledge on specifics pertinent to neurosurgeons and other skull base specialists when planning pre-operatively, such as pathology location, involved anatomical structures, instrument maneuvrability and the advantages and disadvantages of the distinct visualisation technologies. This is all with the intention of selecting the most suitable surgical approach and technology, specific to the patient, pathology and anatomy, so as to perform the best surgical procedure. The research findings illustrated in this body of work are diverse, reproducible and applicable. The transorbital surgical corridor has substantive potential for access to the anterior cranial fossa and specific surgical target structures. The neuroquantitative metrics investigated confirm the utility and benefits specific to the respective visualisation technologies i.e. the endoscope and microscope. The most appropriate setting wherein the approach should be used is also discussed. The transorbital corridor has impressive potential, can utilise all available technological advances, promotes multi-disciplinary co-operation and learning amongst clinicians and ultimately, is a means of improving operative patient care.
ContributorsHoulihan, Lena Mary (Author) / Preul, Mark C. (Thesis advisor) / Vernon, Brent (Thesis advisor) / O' Sullivan, Michael G.J. (Committee member) / Lawton, Michael T. (Committee member) / Santarelli, Griffin (Committee member) / Smith, Brian (Committee member) / Arizona State University (Publisher)
Created2021
Description
The production and incineration of single-use micropipette tips and disposable gloves, which are heavily used within laboratory facilities, generate large amounts of greenhouse gasses (GHGs) and accelerate climate change. Plastic waste that is not incinerated often is lost in the environment. The long degradation times associated with this waste exacerbates a variety of environmental problems such as substance runoff and ocean pollution. The objective of this study was to evaluate the efficacy of possible solutions for minimizing micropipette tip and disposable glove waste within laboratory spaces. It was hypothesized that simultaneously implementing the use of micropipette tip washers (MTWs) and energy-from-glove-waste programs (EGWs) would significantly reduce (p < 0.05) the average combined annual single-use plastic micropipette tip and nitrile glove waste (in kg) per square meter of laboratory space in the United States. ASU’s Biodesign Institute (BDI) was used as a case study to inform on the thousands of different laboratory facilities that exist all across the United States. Four separate research laboratories within the largest public university of the U.S. were sampled to assess the volume of plastic waste from single-use micropipette tips and gloves. Resultant data were used to represent the totality of single-use waste from the case study location and then extrapolated to all laboratory space in the United States. With the implementation of EGWs, annual BDI glove waste is reduced by 100% (0.47 ± 0.26 kg/m2; 35.5 ± 19.3 metric tons total) and annual BDI glove-related carbon emissions are reduced by ~5.01% (0.165 ± 0.09 kg/m2; 1.24 ± 0.68 metric tons total). With the implementation of MTWs, annual BDI micropipette tip waste is reduced by 92% (0.117 ± 0.03 kg/m2; 0.88 ± 0.25 metric tons total) and annual BDI tip-related carbon emissions are reduced by ~83.6% (4.04 ± 1.25 kg/m2; 30.5 ± 9.43 metric tons total). There was no significant difference (p = 0.06) observed between the mass of single-use waste (kg) in the sampled laboratory spaces before (x̄ = 47.1; σ = 43.3) and after (x̄ =0.070; σ = 0.033) the implementation of the solutions. When examining both solutions (MTWs & EGWs) implemented in conjunction with one another, the annual BDI financial savings (in regard to both purchasing and disposal costs) after the first year were determined to be ~$7.92 ± $9.31/m2 (7,500 m2 of total wet laboratory space) or ~$60,000 ± $70,000 total. These savings represent ~15.77% of annual BDI spending on micropipette tips and nitrile gloves. The large error margins in these financial estimates create high uncertainty for whether or not BDI would see net savings from implementing both solutions simultaneously. However, when examining the implementation of only MTWs, the annual BDI financial savings (in regard to both purchasing and disposal costs) after the first year were determined to be ~$12.01 ± $6.79 kg/m2 or ~$91,000 ± $51,200 total. These savings represent ~23.92% of annual BDI spending on micropipette tips and nitrile gloves. The lower error margins for this estimate create a much higher likelihood of net savings for BDI. Extrapolating to all laboratory space in the United States, the total annual amount of plastic waste avoided with the implementation of the MTWs was identified as 8,130 ± 2,290 tons or 0.023% of all solid plastic waste produced in the United States in 2018. The total amount of nitrile waste avoided with the implementation of the EGWs was identified as 32,800 ± 17,900 tons or 0.36% of all rubber solid waste produced in the United States in 2018. The total amount of carbon emissions avoided with the implementation of the MTWs was identified as 281,000 ± 87,000 tons CO2eq or 5.4*10-4 % of all CO2eq GHG emissions produced in the United States in 2020. Both the micropipette tip washer and the glove waste avoidance program solutions can be easily integrated into existing laboratories without compromising the integrity of the activities taking place. Implemented on larger scales, these solutions hold the potential for significant single-use waste reduction.
ContributorsZdrale, Gabriel (Author) / Mahant, Akhil (Co-author) / Halden, Rolf (Thesis director) / Biyani, Nivedita (Committee member) / Driver, Erin (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2022-05
Description
The production and incineration of single-use micropipette tips and disposable gloves, which are heavily used within laboratory facilities, generate large amounts of greenhouse gasses (GHGs) and accelerate climate change. Plastic waste that is not incinerated often is lost in the environment. The long degradation times associated with this waste exacerbates a variety of environmental problems such as substance runoff and ocean pollution. The objective of this study was to evaluate the efficacy of possible solutions for minimizing micropipette tip and disposable glove waste within laboratory spaces. It was hypothesized that simultaneously implementing the use of micropipette tip washers (MTWs) and energy-from-glove-waste programs (EGWs) would significantly reduce (p < 0.05) the average combined annual single-use plastic micropipette tip and nitrile glove waste (in kg) per square meter of laboratory space in the United States. ASU’s Biodesign Institute (BDI) was used as a case study to inform on the thousands of different laboratory facilities that exist all across the United States. Four separate research laboratories within the largest public university of the U.S. were sampled to assess the volume of plastic waste from single-use micropipette tips and gloves. Resultant data were used to represent the totality of single-use waste from the case study location and then extrapolated to all laboratory space in the United States. With the implementation of EGWs, annual BDI glove waste is reduced by 100% (0.47 ± 0.26 kg/m2; 35.5 ± 19.3 metric tons total) and annual BDI glove-related carbon emissions are reduced by ~5.01% (0.165 ± 0.09 kg/m2; 1.24 ± 0.68 metric tons total). With the implementation of MTWs, annual BDI micropipette tip waste is reduced by 92% (0.117 ± 0.03 kg/m2; 0.88 ± 0.25 metric tons total) and annual BDI tip-related carbon emissions are reduced by ~83.6% (4.04 ± 1.25 kg/m2; 30.5 ± 9.43 metric tons total). There was no significant difference (p = 0.06) observed between the mass of single-use waste (kg) in the sampled laboratory spaces before (x̄ = 47.1; σ = 43.3) and after (x̄ =0.070; σ = 0.033) the implementation of the solutions.When examining both solutions (MTWs & EGWs) implemented in conjunction with one another, the annual BDI financial savings (in regard to both purchasing and disposal costs) after the first year were determined to be ~$7.92 ± $9.31/m2 (7,500 m2 of total wet laboratory space) or ~$60,000 ± $70,000 total. These savings represent ~15.77% of annual BDI spending on micropipette tips and nitrile gloves. The large error margins in these financial estimates create high uncertainty for whether or not BDI would see net savings from implementing both solutions simultaneously. However, when examining the implementation of only MTWs, the annual BDI financial savings (in regard to both purchasing and disposal costs) after the first year were determined to be ~$12.01 ± $6.79 kg/m2 or ~$91,000 ± $51,200 total. These savings represent ~23.92% of annual BDI spending on micropipette tips and nitrile gloves. The lower error margins for this estimate create a much higher likelihood of net savings for BDI. Extrapolating to all laboratory space in the United States, the total annual amount of plastic waste avoided with the implementation of the MTWs was identified as 8,130 ± 2,290 tons or 0.023% of all solid plastic waste produced in the United States in 2018. The total amount of nitrile waste avoided with the implementation of the EGWs was identified as 32,800 ± 17,900 tons or 0.36% of all rubber solid waste produced in the United States in 2018. The total amount of carbon emissions avoided with the implementation of the MTWs was identified as 281,000 ± 87,000 tons CO2eq or 5.4*10-4 % of all CO2eq GHG emissions produced in the United States in 2020. Both the micropipette tip washer and the glove waste avoidance program solutions can be easily integrated into existing laboratories without compromising the integrity of the activities taking place. Implemented on larger scales, these solutions hold the potential for significant single-use waste reduction.
ContributorsMahant, Akhil (Author) / Zdrale, Gabriel (Co-author) / Halden, Rolf (Thesis director) / Biyani, Nivedita (Committee member) / Driver, Erin (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor)
Created2022-05
Description
Diabetes affects millions of people globally and can lead to other severe health complications when undiagnosed or not properly managed. The incidence of diabetes has rapidly increased over the past several years, however, not all individuals have access to affordable or convenient healthcare. We hypothesize that wastewater-based epidemiology (WBE) has the potential to assess community health status by analyzing biomarkers indicative of human health and disease, including diabetes. Used in tandem with current methods, monitoring indicators of diabetes in community wastewater could provide a comprehensive assessment tool for disease prevalence in large and small populations. Specifically, the proposed targeted biomarker evaluated in this study to indicate population-wide diabetes prevalence was 8-hydroxy-2’- deoxyguanosine (8-OHdG). This work combines a rigorous literature review and initial laboratory studies to explore the possibility of diabetes monitoring at the community level using WBE. Here, 24-hour composite wastewater samples were collected from within two wastewater sub-catchments of Greater Tempe, AZ. Overall goals of this study were to: i) Determine the feasibility to detect endogenous markers of diabetes in community wastewater; ii) Assess the potential impact of confounding factors, such as smoking, cancer, and atherosclerosis, through a literature analysis; and iii) Evaluate the socioeconomic status and demographics of the study population. Preliminary results of the experiments suggest this methodology to be feasible, as indicated by the observation of detectable signals of 8-OHdG in community wastewater collected from the sewer infrastructure; however, future work and continued experimentation will be required to address low signal intensity and assay precision and accuracy. Thus, the work presented here provides valuable proof-of-concept data, with detailed information on the method employed and identified opportunities to further determine the relationship between 8-OHdG concentrations in municipal wastewater and diabetes prevalence at the community level.
ContributorsNguyen, Jasmine (Author) / John, Dona (Co-author) / Halden, Rolf (Thesis director) / Driver, Erin (Committee member) / Bowes, Devin (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Department of Finance (Contributor)
Created2022-05
Description
Diabetes affects millions of people globally and can lead to other severe health complications when undiagnosed or not properly managed. The incidence of diabetes has rapidly increased over the past several years, however, not all individuals have access to affordable or convenient healthcare. We hypothesize that wastewater-based epidemiology (WBE) has the potential to assess community health status by analyzing biomarkers indicative of human health and disease, including diabetes. Used in tandem with current methods, monitoring indicators of diabetes in community wastewater could provide a comprehensive assessment tool for disease prevalence in large and small populations. Specifically, the proposed targeted biomarker evaluated in this study to indicate population-wide diabetes prevalence was 8-hydroxy-2’-deoxyguanosine (8-OHdG). This work combines a rigorous literature review and initial laboratory studies to explore the possibility of diabetes monitoring at the community level using WBE. Here, 24-hour composite wastewater samples were collected from within two wastewater sub-catchments of Greater Tempe, AZ. Overall goals of this study were to: i) Determine the feasibility to detect endogenous markers of diabetes in community wastewater; ii) Assess the potential impact of confounding factors, such as smoking, cancer, and atherosclerosis, through a literature analysis; and iii) Evaluate the socioeconomic status and demographics of the study population. Preliminary results of the experiments suggest this methodology to be feasible, as indicated by the observation of detectable signals of 8-OHdG in community wastewater collected from the sewer infrastructure; however, future work and continued experimentation will be required to address low signal intensity and assay precision and accuracy. Thus, the work presented here provides valuable proof-of-concept data, with detailed information on the method employed and identified opportunities to further determine the relationship between 8-OHdG concentrations in municipal wastewater and diabetes prevalence at the community level.
ContributorsJohn, Dona (Author) / Nguyen, Jasmine (Co-author) / Halden, Rolf (Thesis director) / Driver, Erin (Committee member) / Bowes, Devin (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor) / Department of Psychology (Contributor)
Created2022-05
Description
Currently, there are a number of studies confirming the link between exposure to certain chemicals, notably pesticides (Costello et. al. 2009, Wang et. al 2014), heavy metals such as arsenic (Chen et. al. 2017), ambient air pollution (Chen et. al. 2016), and chemicals specific to certain industrial fields (Nielsen et. al. 2021). However, few papers have attempted to perform a widespread analysis of the factors associated with Parkinson’s disease to identify whether the risk of developing the disease is dependent on different factors regionally. The goal of my thesis project is to complete a meta-analysis of toxins- where exposure may occur in both residential and occupational settings- that are associated with Parkinson’s to determine such regional differences and to identify any gaps in current literature, which may direct the course of future research in the field. As seen in this paper, it appears that occupational exposure to toxins appears to have the greatest impact on the risk of developing Parkinson’s disease, particularly pesticides and industrial toxins. However, there are numerous gaps with regards to data collection, regions studied, and quantification of toxin concentrations. However, this data may be useful in identifying at-risk populations if more extensive incremental and biopsy data regarding these toxins is provided.
ContributorsAravindan, Anumitha (Author) / Halden, Rolf (Thesis director) / Driver, Erin (Committee member) / Newell, Melanie (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2022-05
Description
Heavy metals and persistent organic pollutants contribute to human health risks worldwide. Among the most common routes of exposure to pollutants for humans are through the consumption of contaminated water and food, with fish being among the greatest vectors for ingestion of heavy metals in humans, particularly mercury.This dissertation consists of three chapters with a central theme of investigating heavy metal and persistent organic pollutant concentrations in fish and corned beef, which are two commonly consumed food items in American Samoa. A literature review illustrated that historically the primary pollutants of concern in fish muscle tissue from American Samoa have been mercury, arsenic, and polycyclic aromatic hydrocarbon mixtures. To better understand the changes in heavy metals and persistent organic pollutants in fish, this study reports an updated data set, comparing concentrations in pollutants as they have changed over time. To further investigate pollutants in fish tissue, 77 locally caught and commonly consumed fish were analyzed for heavy metals and persistent organic pollutants, and baseline human health risk assessments were calculated for contaminants that had available oral reference doses. While in American Samoa collecting fish for contaminant analyses, it was realized that canned corned beef appeared to be more commonly consumed than fresh fish. An IRB approved consumption survey revealed that 89% of American Samoan adults regularly consume fish, which is the same percentage of people that reported eating canned corned beef, indicating a dramatic increase in this food item to their diet since its introduction in the 20th century.
Results of this study indicate that fish muscle tissue generally has higher heavy metal concentrations than canned corned beef, and that mercury continues to be a main contaminant of concern when consuming fresh and canned fish in American Samoa. While none of the heavy metal concentrations in corned beef exceeded calculated action levels, these foods might contribute to negative health outcomes in other ways. One of the main findings of this study is that either the presence or the ability to detect persistent organic pollutant concentrations are increasing in fish tissue and should be periodically monitored to adequately reflect current conditions.
ContributorsLewis, Tiffany Beth (Author) / Polidoro, Beth (Thesis advisor) / Neuer, Susanne (Thesis advisor) / Halden, Rolf (Committee member) / Schoon, Michael (Committee member) / Arizona State University (Publisher)
Created2023
Description
Olfactory perception is a complex and multifaceted process that involves the detection of volatile organic compounds by olfactory receptor neurons in the nasal neuroepithelium. Different odorants can elicit different perceived intensities at the same concentration, while direct intensity ratings are vulnerable to framing effects and inconsistent scale usage. Odor perception is genetically determined, with each individual having a unique olfaction "footprint" and sensitivity levels. Genetic factors, age, gender, race, and environmental factors influence olfactory acuity. The olfactory system's complexity makes it challenging to create a standardized comparison system for olfactory perception tests. The COVID-19 pandemic has underscored the importance of olfactory dysfunction, particularly the loss of smell and taste as common symptoms. Research has demonstrated the widespread occurrence of olfactory impairment in various populations, often stemming from post-viral origins, which is the leading cause of permanent smell loss. Utilizing quantitative ranking on a qualitative scale enhances the precision and accuracy when evaluating and drawing conclusions about odor perception and how to mitigate problems caused by external factors. Pairwise comparisons enhance the accuracy and consistency of results and provide a more intuitive way of comparing items. Such ranking techniques can lead to early detection of olfactory disorders and improved diagnostic tools. The COVID-19 pandemic has shed light on the significance of olfactory dysfunction, emphasizing the need for further research and standardized testing methods in olfactory perception.
ContributorsDarden, Jaelyn (Author) / Smith, Brian (Thesis advisor) / Gerkin, Richard (Thesis advisor) / Spackman, Christy (Committee member) / Arizona State University (Publisher)
Created2023
Description
Development of the central nervous system is an incredible process that relies on multiple extracellular signaling cues and complex intracellular interactions. Approximately 1500 genes are associated with neurodevelopmental disorders, many of which are linked to a specific biochemical signaling cascade known as Extracellular-Signal Regulated Kinase (ERK1/2). Clearly defined mutations in regulators of the ERK1/2 pathway cause syndromes known as the RASopathies. Symptoms include intellectual disability, developmental delay, cranio-facial and cardiac deficits. Treatments for RASopathies are limited due to an in complete understanding of ERK1/2’s role in brain development. Individuals with Neurofibromatosis Type and Noonan Syndrome, the two most common RASopathies, exhibit aberrant functional and white matter organization in non-invasive imaging studies, however, the contributions of neuronal versus oligodendrocyte deficits to this phenotype are not fully understood. To define the cellular functions of ERK1/2 in motor circuit formation, this body of work focuses on two long-range projection neuron subtypes defined by their neurotransmitter. With genetic mouse models, pathological ERK1/2 in glutamatergic neurons reduces axonal outgrowth, resulting in deficits in activity dependent gene expression and the ability to learn a motor skill task. Restricting pathological ERK1/2 within cortical layer V recapitulates these wiring deficits but not the behavioral learning phenotype. Moreover, it is uncovered that pathological ERK1/2 results in compartmentalized expression pattern of phosphorylated ERK1/2. It is not clear whether ERK1/2 functions are similar in cholinergic neuron populations that mediate attention, memory, and motor control. Basal forebrain cholinergic neuron development relies heavily on NGF-TrKA neurotrophic signaling known to activate ERK1/2. Yet the function of ERK1/2 during cholinergic neuronal specification and differentiation is poorly understood. By selectively deleting ERK1/2 in cholinergic neurons, ERK1/2 is required for activity-dependent maturation of neuromuscular junctions in juvenile mice, but not the establishment of lower motor neuron number. Moreover, ERK1/2 is not required for specification of choline acetyltransferase expressing basal forebrain cholinergic neurons by 14 days of age. However, ERK1/2 may be necessary for BFCN maturation by adulthood. Collectively, these data indicate that glutamatergic neuron-autonomous decreases in long-range axonal outgrowth and modest effects on later stages of cholinergic neuron maintenance may be important aspects of neuropathogenesis in RASopathies.
ContributorsRees, Katherina Pavy (Author) / Newbern, Jason (Thesis advisor) / Olive, Foster (Committee member) / Qiu, Shenfeng (Committee member) / Sattler, Rita (Committee member) / Smith, Brian (Committee member) / Arizona State University (Publisher)
Created2024