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Title: The regulation surrounding the triose phosphate utilization limitation of photosynthesis
Creator: McClain, Alan M.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The triose phosphate utilization (TPU) limitation of photosynthesis is a paradigm in which the rate at which stromal phosphate is incorporated into the organic phosphate pool can exceed the rate at which inorganic phosphate is released by processing fixed carbon into end products such as starch or sucrose. TPU limitation is unique among the three canon biochemical limitations of photosynthesis in that the plant must regulate photosynthetic rate to a level below what is maximally possible in...
Show moreThe triose phosphate utilization (TPU) limitation of photosynthesis is a paradigm in which the rate at which stromal phosphate is incorporated into the organic phosphate pool can exceed the rate at which inorganic phosphate is released by processing fixed carbon into end products such as starch or sucrose. TPU limitation is unique among the three canon biochemical limitations of photosynthesis in that the plant must regulate photosynthetic rate to a level below what is maximally possible in its current environment.I investigated the methods through which the photosynthetic rate is regulated in response to TPU limitation. For the first minute after imposition of TPU limitation by excess light and CO2, the photosynthetic rate is limited by oscillations in availability of NADP+ for photosystem I and availability of inorganic phosphate for the chloroplastic ATP synthase. These oscillations cause variance in the redox state of the electron carrier Qa which primarily controls energy flow during photosynthesis. After a few minutes, slower energy-dependent regulatory mechanisms at photosystem II and the cytochrome b6f complex reduce energy flow, relieving any excess reduction at Qa or photosystem I. After a day of acclimation, photoinhibition and rubisco deactivation prevent the appearance of TPU limitation at elevated CO2 and also prevented the occurrence of oscillations in photosynthetic electron carrier redox status. Oscillations induced by TPU limitation are temporarily able to exceed the steady-state photosynthetic rate. However, the advantage is short-lived, and overall plants assimilate less over the course of oscillations than they would during steady-state photosynthesis. The plants can temporarily exceed the limitation on photosynthesis typically imposed by TPU limitation or the RuBP regeneration limitation, but not the rubisco limitation. This is due to the availability of metabolites caused by a brief period of inactivity. Furthermore, the amplitude of the oscillations depended on how quickly the plant entered TPU limitation and how severe TPU limitation was when imposed.
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Title: The relationship of aging on the rate of vocal fatigue based on personal rating scales and fundamental frequency
Creator: Sowa, Olivia Rae
Date: 2018
Collection: Electronic Theses & Dissertations
Description: INTRODUCTION: The relationship between aging and the quality of voice has been researched for the last several decades. Multiple studies have found that females older than 40 consistently experience more instances of voice problems than their male counterparts. RESEARCH QUESTION: to what degree does a vocal loading task fatigue older women? How does the rate of vocal fatigue compare to that found in younger women? METHODS: Eleven female subjects from the age of 55-70 years old were recruited....
Show moreINTRODUCTION: The relationship between aging and the quality of voice has been researched for the last several decades. Multiple studies have found that females older than 40 consistently experience more instances of voice problems than their male counterparts. RESEARCH QUESTION: to what degree does a vocal loading task fatigue older women? How does the rate of vocal fatigue compare to that found in younger women? METHODS: Eleven female subjects from the age of 55-70 years old were recruited. Participants read aloud for 36 minutes at predetermined dB levels in an attempt to induce vocal fatigue. Subjective and acoustic vocal measures were taken not before and after the vocal loading task and at intervals during the task. RESULTS: Subjective results, acoustical parameters, and comparison data from the younger population were found to not be significant. CONCLUSION: The results of the study showed that vocal loading task did vocally fatigue the participants based on subjective ratings. Acoustically there trending evidence of fatigue from the loading task. The aging female population did not vocally fatigue at any greater rate than their younger counterparts. However, there was evidence that fatigue rate did relate to pulmonary health (estimated lung age) in the older population.
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Title: The relevance of physics : a critical look at the ways in which students find meaning in introductory physics
Creator: Nair, Abhilash (Graduate of Michigan State University)
Date: 2018
Collection: Electronic Theses & Dissertations
Description: The relevance of physics is an active line of inquiry within the physics education research (PER) community. Many studies have shown that physics instruction typically negatively impacts students' sense of the relevance of physics to their lives. Irrespective of students' beliefs, physics is communicated as being relevant through policy recommendations and program requirements. Until now, most efforts in PER to measure or interpret students' beliefs around relevance have been limited to...
Show moreThe relevance of physics is an active line of inquiry within the physics education research (PER) community. Many studies have shown that physics instruction typically negatively impacts students' sense of the relevance of physics to their lives. Irrespective of students' beliefs, physics is communicated as being relevant through policy recommendations and program requirements. Until now, most efforts in PER to measure or interpret students' beliefs around relevance have been limited to attitudinal and epistemological surveys that provide an incomplete picture and tends to promote deficit interpretations of students' abilities. We first challenge notions of the "real world" and "everyday life" that are ubiquitous in current efforts to understand relevance. These phrases lack meaning and we use case studies of students to argue for an expanded holistic view of relevance. We then introduce a framework that accomplishes viewing relevance in an expanded fashion by adapting ecological systems theory. We trace students' experiences to argue that this framework provides a richer picture of what it means for physics to be relevant to a student. Finally, we present a longitudinal case study of a student who experiences a remarkable transformation in his view of physics. Through the lens of relevance, we articulate the connections he makes during his journey through introductory physics. These connections end up being critical for a lasting impact that empowers him to promote the relevance of physics to others. We argue in this dissertation that using this framework of relevance, physics educators can start to design classrooms that facilitate more positive affective and attitudinal experiences for students. Through relevance, physics classrooms can become inclusive and engaging environments for students to forge lasting connections to a discipline.
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Title: The rising risk of rising water : examining risk perception and other predictors of flood mitigation behavior
Creator: Rappolee, Eleanor
Date: 2020
Collection: Electronic Theses & Dissertations
Description: As a result of heat-trapping pollution from human activities, rising sea levels and increasing precipitation could within three decades push chronic floods on land currently home to more than 300 million people. Water levels in the Great Lakes, heavy rainfall, and flooding have all substantially increased in Michigan, causing erosion, water quality decline, and negative impacts on society. Taking action to mitigate flooding at all scales is essential to ensure social and economic...
Show moreAs a result of heat-trapping pollution from human activities, rising sea levels and increasing precipitation could within three decades push chronic floods on land currently home to more than 300 million people. Water levels in the Great Lakes, heavy rainfall, and flooding have all substantially increased in Michigan, causing erosion, water quality decline, and negative impacts on society. Taking action to mitigate flooding at all scales is essential to ensure social and economic sustainability. This study explores predictor variables of flood mitigation behaviors among Michigan residents in a proposed theoretical framework that synthesizes three behavioral theories: Theory of Planned Behavior, Values-Beliefs-Norms, and Protection Motivation Theory. This study also includes empirically measured actual flood risk in the theoretical framework, which is often left out in behavioral studies. Actual flood risk alone was found to weakly align with perceived flood risk and was a significant predictor of flood mitigation behavior during regression. However, when other variables were included, actual flood risk became an insignificant part of the model. Instead, subjective norms, perceived flood risk, self-efficacy, education level, having a flood-related home inspection, and having a basement emerged as significant predictors of flood mitigation behaviors. These findings lay the groundwork for future research and have implications for planning around flood mitigation and policy within and beyond the Midwest region.
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Title: The role of G-protein coupled receptor kinase 2 in mucosal inflammation
Creator: Steury, Michael
Date: 2017
Collection: Electronic Theses & Dissertations
Description: G-protein coupled receptor kinases (GRKs) are a family of protein kinases comprised of seven serine/threonine kinases that were initially identified for their ability to phosphorylate G-protein coupled receptors (GPCRs). Furthermore, it has recently become evident that individual GRKs can interact in a kinase dependent or independent manner with non-receptor substrates and influence a variety of physiological functions and pathologies. This study focuses on the family member GRK2. GRK2 is...
Show moreG-protein coupled receptor kinases (GRKs) are a family of protein kinases comprised of seven serine/threonine kinases that were initially identified for their ability to phosphorylate G-protein coupled receptors (GPCRs). Furthermore, it has recently become evident that individual GRKs can interact in a kinase dependent or independent manner with non-receptor substrates and influence a variety of physiological functions and pathologies. This study focuses on the family member GRK2. GRK2 is expressed ubiquitously throughout the body and in addition to phosphorylating and regulating GPCR function, GRK2 is able to phosphorylate and/or interact with a large interactome of cellular proteins in a tissue - and context - specific manner. This combination of canonical and non- canonical roles of GRK2 is now attributed to a multitude of vital physiological functions including: cell migration, proliferation, metabolism, angiogenesis, and insulin resistance. This vast array of influence makes GRK2 a popular target of study for both diagnostic opportunities as well as therapeutic interventions and while GRK2 has been extensivelystudied in cardiac and immune cells its role in the intestine and the intestinal epithelium is not well understood.Inflammatory bowel disease is characterized by damage to the intestinal epithelial barrier resulting in increased permeability and the resultant dissemination of the commensal microbiota. This translocation of the luminal contents into the lamina propria constantly stimulates the immune system leading to its hyper-activation and eventual damage to the intestine. Inflammatory bowel disease is associated with increases in inflammatory cytokine production, namely TNFα and this study was performed to investigate the regulation of GRK2 on TNFα signaling in the intestinal epithelial cells and in a larger context its role in the regulation in onset and pathogenesis of acute colitis. We found that decreasing the levels of GRK2 in human epithelial cells influenced the induction of ROS production by TNFα that influences ERK1/2 signaling and the production of MMP9 to influence wound closure both in culture and in animal models. Furthermore, mice heterozygous for GRK2 were markedly protected from the onset and pathogenesis of acute DSS-induced colitis in the absence of any alterations in immune infiltration. Myeloid specific knockout studies showed this population to be in part responsible for the protection seen in the whole body knockout. Together these studies suggest that GRK2 may serve as a novel therapeutic option for the treatment of colitis.
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Title: The role of International Soybean Trade in Telecoupled Human and Natural Systems
Creator: Herzberger, Anna Jean
Date: 2020
Collection: Electronic Theses & Dissertations
Description: International food trade and globalized agriculture production connects humans and the environment around the world. As consumption demands are increasingly met abroad by importing food products, environmental and socioeconomic effects of production are left in the producing region, while the effects on the importing countries’ domestic production remain understudied due to the complexity and low visibility of the impacts. As population growth increases the caloric demand and rising affluence...
Show moreInternational food trade and globalized agriculture production connects humans and the environment around the world. As consumption demands are increasingly met abroad by importing food products, environmental and socioeconomic effects of production are left in the producing region, while the effects on the importing countries’ domestic production remain understudied due to the complexity and low visibility of the impacts. As population growth increases the caloric demand and rising affluence drives changes in consumption patterns, connections via food trade will continue to increase. Therefore, to identify local impacts of global phenomena, this dissertation analyses the environmental and socioeconomic impacts of international soybean trade within Brazil (e.g., largest producer), China (e.g., largest consumer) and the U.S. (e.g., the former largest producer). Drawing from both natural and social science disciplines, global trade data, satellite-imagery, farmer interviews and soil samples were combined for an interdisciplinary assessment of how international soybean trade couples distant human and the environment systems, the true extent of land-use change driven by soybean trade and the resulting impacts within each respective country. Chapter 1 provides a review of the published literature and background on international soybean trade and production. In chapter 2, the influence of China’s soybean demand was measured on Brazil’s production and trade. The results suggest that export-oriented soybean expansion in Brazil displaced the production of other crops and increased imports from nearby countries. For chapter 3, the impact of imported soybeans on production in China’s main agricultural region was explored. Competition from imported soybeans has resulted in many farmers switching cultivation to corn or to abandon farming in search of more lucrative options. This cultivation shift requires changes in management that involve increased nitrogen inputs and residual crop biomass – both of which have resulted in environmental spillovers. Chapter 4 furthered the analysis by considering the impacts of farmer cultivation and management decisions on soil properties. Soil texture, pH, total organic carbon and 16S rRNA gene sequence were used in combination with detailed farmer management surveys to understand how changes in residue management effect efficiency, productivity, profitability and sustainability of the system. The results indicated that the accumulation of residual corn biomass has increased the use of residue fires and decreased the amount of crop residue being returned to the soil. The culminating chapter used an agent-based modeling (ABM) to integrate the above chapters into a TeleABM. The teleABM models land use change in Brazil and China based on global soybean demand. Land-use change decisions are made by farmer agents which have parametrized using the farmer interviews. Next, the farmer agent cultivation and management decisions have environmental impacts that were determined by analyzing the soil samples under the context of management decisions. Finally, production and the impact of farmer agent decisions on the soil properties feedback to the farmer’s future cultivation and management decisions. Because of the economic, environmental and political importance of international soybean trade, the results of this dissertation are of great interest for future soybean production and trade between the specified countries as well as food security and environmental sustainability across the world.
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Title: The role of biodiversity in prairie restoration : tests of theory and implications for management
Creator: Bassett, Tyler Jacob
Date: 2017
Collection: Electronic Theses & Dissertations
Description: "Biodiversity is a primary focus of conservation and restoration, because it has intrinsic value, and because it supports the ecosystem functioning that human well being ultimately depends upon. Theory and experiments support the hypothesis that greater diversity in plant communities supports greater primary productivity, nutrient cycling, invasion resistance and a range of other processes linked to the healthy functioning of ecosystems. However, most of the evidence for diversity-function...
Show more"Biodiversity is a primary focus of conservation and restoration, because it has intrinsic value, and because it supports the ecosystem functioning that human well being ultimately depends upon. Theory and experiments support the hypothesis that greater diversity in plant communities supports greater primary productivity, nutrient cycling, invasion resistance and a range of other processes linked to the healthy functioning of ecosystems. However, most of the evidence for diversity-function relationships is from manipulations of diversity, and a limited number of environmental variables, in small-scale plots. As a result, it is unclear how diversity-function relationships will scale up to dynamic, "real-world" ecosystems, which limits the capacity to effectively manage both biodiversity and ecosystem functioning. I examined diversity-function relationships in prairie restorations, which provide an ideal scenario for bridging the gap between experimental and natural ecosystems because diversity is manipulated at large scales and across complex biotic and abiotic gradients. It is clear from experimental evidence that diversity plays a role in supporting ecosystem functioning. My findings elucidate how important diversity is at the scale of natural ecosystems, relative to both abiotic (e.g., soil properties) and biotic (e.g., dominant species) factors that are likely to covary with diversity at large scales. I also contribute directly to the practice of restoration by working in real restorations, linking variation in management actions, such as seed sowing and prescribed fire, to outcomes of immediate concern to managers, such as the relationship between native and exotic species."--Abstract.
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Title: The role of evidence in animal welfare science and standards : an ethical analysis
Creator: List, Monica
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The development of the field of animal welfare science in recent decades, together with growth in public interest and ethical concerns for the welfare of animals has arguably led to an increase in regulation, both public and private, in the production and use of farmed animals. Animal welfare regulation, in the form of legislation, directives, industry guidelines and private standards is characterized by its reliance on scientific evidence to justify the conditions under which farmed animals...
Show moreThe development of the field of animal welfare science in recent decades, together with growth in public interest and ethical concerns for the welfare of animals has arguably led to an increase in regulation, both public and private, in the production and use of farmed animals. Animal welfare regulation, in the form of legislation, directives, industry guidelines and private standards is characterized by its reliance on scientific evidence to justify the conditions under which farmed animals should be bred, raised, transported, and slaughtered. One of the important roles scientific evidence plays in discussions around the regulation of farmed animal welfare is providing a seemingly ethically neutral understanding of how animals should be treated, in other words, it sidesteps ethical arguments for the treatment of animals, using science as a justification. However, per the dominant philosophy of science discourse on the role of values in science, no science can be considered value-free, and furthermore, there are acceptable roles for social and ethical values in scientific practice. These roles are not just acceptable, but necessary for the direction, interpretation, and application of science. This work argues that: a) given the broad range of ethical views regarding how we should treat animals, animal welfare science provides robust and credible guidance; b) furthermore, that animal welfare science is not only inspired or informed by animal ethics concepts and frameworks, but also has embedded social/ethical and cognitive values throughout; c) thus, in order to fulfil its purpose as a socially mandated science, animal welfare science should engage in intentional processes to determine adequate roles for various kinds of values underlying all stages of the scientific process and the interpretation and implementation of findings. This intentional examination of the role of values can be supported by more effective interdisciplinary collaboration. While animal welfare science is characterized in part by its interdisciplinary nature, it is important to question to what extent the research is truly interdisciplinary in the sense of fostering epistemic integration. Philosophical tools and analyses, beyond the typical uses of ethical frameworks as a starting point, can be valuable in facilitating effective interdisciplinary work, leading to a better understanding of the normative dimensions of animal welfare science.
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Title: The role of inflammation and the kynurenine pathway in mood disorders and pregnancy
Creator: Keaton, Sarah A.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "Inflammation and the kynurenine pathway are involved in multiple physiological and pathophysiological states, however their role in depression during and after pregnancy, suicidality, and pre-eclampsia remain to be understood. Here, we sought to understand how the kynurenine pathway and its metabolites as well as their interactions with inflammation may influence these conditions. First, we analyzed suicide warning in women with mood and anxiety disorders. We identified a distinct...
Show more"Inflammation and the kynurenine pathway are involved in multiple physiological and pathophysiological states, however their role in depression during and after pregnancy, suicidality, and pre-eclampsia remain to be understood. Here, we sought to understand how the kynurenine pathway and its metabolites as well as their interactions with inflammation may influence these conditions. First, we analyzed suicide warning in women with mood and anxiety disorders. We identified a distinct immunobiological profile linked to cross-diagnostic suicide risk in women with mood disorders, attending a psychiatric outpatient clinic. This consisted of a strong proinflammatory profile, containing white blood cell count and polymononuclear leukocyte cell count which may be associated with the underlying pathobiology of suicide warning.. Next, we analyzed inflammation and the kynurenine pathway in peripartum depression and postpartum depression and suicidality to understand how they could influence psychiatric health. We found plasma IL-6 predicted depression scores throughout the first, second, and third trimester. In the third trimester we found increased neurotoxic kynurenine metabolite quinolinic acid in the plasma of women with depression compared to health controls. Additionally, we found plasma IL-1beta and IL-6 correlated with placental tissue expression of indolamine 2,3-dioxygenase 1 (IDO) connecting the placenta with peripheral inflammation in the plasma. There was a different inflammatory profile in postpartum depression and suicidality, with increased IL-8 and decreased IL-2, indicating the mechanisms causing peripartum depression and postpartum depression may be different. Finally, we looked at placentas from women with pre-eclampsia compared to healthy controls and found they had dysregulated tryptophan metabolism. There was a decrease of IDO, a compensatory increase in expression of tryptophan-2,3-dioxygenase, and this was associated with a decrease of serum amyloid A. Collectively, this dissertation highlights the importance of inflammation and the kynurenine pathway in the pathophysiology of psychiatric disorders and pregnancy states in females. Further research of inflammation and the kynurenine pathway may lead to screening panels and treatments for suicide, peripartum depression, postpartum depression and suicidality, and pre-eclampsia."--Pages ii-iii.
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Title: The role of lateral hypothalamic neurotensin neurons in adaptive energy balance
Creator: Brown, Juliette Anne
Date: 2017
Collection: Electronic Theses & Dissertations
Description: The lateral hypothalamic area (LHA), receives cues of energy and fluid status from the body and coordinates appropriate feeding, drinking and activity (e.g. adaptive responses) to ensure survival. The LHA contains many distinct populations of neurons, however, and it remains unclear how each of these contribute to energy balance. Here we sought to understand how LHA neurons expressing the neuropeptide neurotensin (LHA Nts neurons) coordinate distinct behaviors necessary for adaptive response...
Show moreThe lateral hypothalamic area (LHA), receives cues of energy and fluid status from the body and coordinates appropriate feeding, drinking and activity (e.g. adaptive responses) to ensure survival. The LHA contains many distinct populations of neurons, however, and it remains unclear how each of these contribute to energy balance. Here we sought to understand how LHA neurons expressing the neuropeptide neurotensin (LHA Nts neurons) coordinate distinct behaviors necessary for adaptive response and control of body weight. While activation of most LHA Neurons increases both feeding and drinking, activation of LHA Nts neurons specifically promotes drinking but reduces feeding. LHA Nts neurons may exert these divergent actions via distinct circuits, as they have been shown to modulate dopamine (DA) signaling and local orexin (OX) neurons. Consistent with this, we have distinguished two projection-specific and molecularly distinct subsets of LHA Nts neurons. One subset co-expresses Nts and the long form of the leptin receptor (LepRb), is activated by leptin and projects to the ventral tegmental area (VTA) and substantia nigra compacta (SNc); we refer to these as NtsLepRb neurons. A separate subset of LHA Nts neurons lacks LepRb, is activated by dehydration and does not project to the VTA or SNc; we refer to these as Nts Dehy neurons. Intriguingly, however, we found all LHA Nts neurons are similar in that they express the inhibitory neurotransmitter, GABA. We next investigated the role of the NtsLepRb subpopulation for adaptive response by studying mice lacking leptin signaling via Nts LepRb neurons. Loss of leptin regulation only via NtsLepRb neurons induced obesity, blunted adaptive response to leptin and to ghrelin (a hormonal activator of OX neurons) and dysregulated DA signaling. Finally, we defined the necessity of LHA Nts neurons for energy balance by genetically ablating or chemogenetically inhibiting them in adult mice. Prolonged loss of LHA Nts neurons decreased drinking, locomotor activity and deranged OX expression in target neurons that led to increased adiposity. By contrast, LHA Nts inhibition preserved OX expression but still blunted locomotor activity. Together these data suggest that LHA Nts neurons modulate physical activity that is not dependent on OX, but that the LHA Nts→OX circuit is necessary for regulation of drinking and adiposity. Collectively, our data show that LHA Nts neurons are necessary for regulation of adaptive energy balance, and that distinct subpopulations of LHA Nts neurons may control ingestive and locomotor behavior via OX-dependent and independent pathways. This work suggests that there may be unique LHA Nts circuits to regulate drinking, motivated feeding ingestive disorders such as obesity, anorexia nervosa, psychogenic polydipsia and dehydration.
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Title: The role of oxytocin receptors in the dorsomedial tegmentum in postpartum socioemotional behaviors
Creator: Grieb, Zachary Adam
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Oxytocin signaling is well known to positively influence maternal caregiving behaviors. Therefore, oxytocin receptor (OTR) expression has been characterized in many sites of the brain across female reproductive states. However, almost all characterization of OTRs across reproduction has focused on forebrain sites, even though there are known OTRs in the midbrain dorsal raphe (DR) and periaqueductal gray (PAG) (i.e., the dorsomedial tegmentum). Ignoring these sites is surprising, given that...
Show moreOxytocin signaling is well known to positively influence maternal caregiving behaviors. Therefore, oxytocin receptor (OTR) expression has been characterized in many sites of the brain across female reproductive states. However, almost all characterization of OTRs across reproduction has focused on forebrain sites, even though there are known OTRs in the midbrain dorsal raphe (DR) and periaqueductal gray (PAG) (i.e., the dorsomedial tegmentum). Ignoring these sites is surprising, given that these sites are part of the neurobiological network underlying postpartum behaviors (see background review in Chapter One). To begin to understand the role of OTRs in the dorsomedial tegmentum on postpartum behavior, the experiments in Chapter Two of this dissertation measured autoradiographic binding of the selective OTR antagonist, d(CH2)5–8-ornithine-vasotocin, across four different female reproductive states, diestrous virgins (DV), pregnancy day 10, day of parturition, and postpartum day 7 (PPD 7). OTR binding in the rostral DR and the lateral PAG were higher in recently-parturient dams compared to DV females, but these levels were returned to DV levels by PPD 7. Additionally, there was increased oxytocin-immunoreactive (ir) fiber length in the DR and PAGvl in PPD 7 dams compared to either DV or recently-parturient dams. Given the heterogenous populations of cells in the DR, expression of OTRs on three of the most abundant neuronal phenotypes in the DR, serotonin, dopamine, and GABA, were analyzed in groups of DV and recently-parturient dams. There were more dopaminergic and serotonergic neurons containing OTR immunoreactivity in the rostral DR of recently- parturient dams compared to DV, whereas the number of glutamic acid decarboxylase-OTR colocalized cells was lower in the rostral DR of recently-parturient dams compared to DV. Overall, these data suggest that specific regions of the midbrain PAG are more sensitive to oxytocin signaling around parturition, with dopaminergic and serotonergic neurons accounting for some of that increased sensitivity. Given these changes in dorsomedial tegmentum OTR expression across the early postpartum period, their potential role in postpartum socioemotional behaviors was directly examined. An adeno-associated virus promoting the expression of shRNA against OTR mRNA was created to establish a long-term knock down of OTR expression in the dorsomedial tegmentum (Chapter Three). On pregnancy day 8, females received site-specific infusion of either OTR shRNA vector or a scrambled control vector. Following parturition, dams’ socioemotional behaviors (i.e. caregiving, aggressive, anxiety-like, and depressive-like behaviors) were observed. OTR knockdown (OTRKD) in the dorsomedial tegmentum lead to higher rates of infanticide, less kyphotic nursing (i.e., nursing in an upright erect posture), and more non-pup directed behaviors. There were no effects of OTRKD on dams’ retrieval performance. OTRKD in the dorsomedial tegmentum also increased postpartum aggression, decreased postpartum anxiety, and increased depressive-like behaviors. Finally, OTRKD in the dorsomedial tegmentum decreased serotonin-ir fiber length in the primary somatosensory cortex (S1). Overall, OTR expression in the dorsomedial tegmentum is sensitive to female reproductive state and modifies numerous postpartum behaviors. It may do so by affecting the S1 plasticity necessary to optimize maternal tactile sensitivity to offspring (discussed in Chapter Four).
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Title: The role of the axon initial segment and tau modifications in axosomatic tau distribution
Creator: Kneynsberg, Andrew
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Tau is enriched in the axonal compartment in healthy neurons but is mislocalized to the somatodendritic compartment in disease, playing an important role in tauopathy pathogenesis. The localization of tau in axons involves the axon initial segment (AIS), which is a specialized region of the proximal axon that acts as a retrograde diffusion barrier for tau. Here, we examined the timing of AIS development alongside the differential distribution of tau in axons of hippocampal neurons in culture....
Show moreTau is enriched in the axonal compartment in healthy neurons but is mislocalized to the somatodendritic compartment in disease, playing an important role in tauopathy pathogenesis. The localization of tau in axons involves the axon initial segment (AIS), which is a specialized region of the proximal axon that acts as a retrograde diffusion barrier for tau. Here, we examined the timing of AIS development alongside the differential distribution of tau in axons of hippocampal neurons in culture. We also examined AIS morphology and levels of axonal and somatic tau in aging process of Fisher 344 rats. Using tau domains, pseudophosphorylation, and a familial tau mutation combined with a photoconvertible fluorescent construct, we analyzed the diffusion behavior of tau in living hippocampal neurons. We discovered that the microtubule binding region is necessary and sufficient to prevent diffusion from the axon to the soma, and that disease-related changes in tau such as phosphorylation and familial mutation of tau show enhanced axosomatic tau diffusion. Analysis of aged rat brains showed that the AIS-associated protein, Ankyrin G, remains properly localized and abundant during aging, while the axosomatic distribution of tau does not change in hippocampal neuron populations. To further elucidate the mechanisms by which the AIS inhibits retrograde tau mislocalization we used shRNAs to knockdown the expression AIS proteins: Ankyrin G (AnkG) and tripartite motif containing protein 46 (TRIM46). We show that TRIM46 plays a critical role in maintenance of the diffusion barrier in cultured hippocampal neurons. Knockdown of TRIM46 is sufficient to allow somatic diffusion of axonal tau into the somata of neurons and reduce the relative axonal enrichment of tau. Knockdown of AnkG does not change tau localization or axo-somatic distribution. Immunoprecipitation and mass spectrometry was used to characterize this connection between tau and TRIM46, but we conclude that tau and TRIM46 do not interact directly. Instead, we identified TRIM46 interactions with several microtubule-associated and actin-associated proteins supporting an integral role in maintenance of the AIS cytoarchitecture. We propose that the tight regulation of microtubule organization in the AIS by TRIM46 prevents somatic diffusion of tau, and tau modifications that disrupt its interactions with microtubules contributes to axosomatic mislocalization.
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Title: The role of viral load in the progression of HIV diagnosis to development of AIDS in Michigan patients population
Creator: Channavong, Souliya
Date: 2018
Collection: Electronic Theses & Dissertations
Description: "Objective: The primary objective is to emphasize the prognostic value of viral load in the progression of HIV infection diagnosis to development of AIDS in the state of Michigan." -- Abstract.

Title: The search for "self" : cultural identity through representations of parent-child relationships in "Instructions Not Included" (2013) and "Under the Same Moon" (2007)
Creator: Moulding, Charles
Date: 2017
Collection: Electronic Theses & Dissertations
Description: This thesis analyzes the films Instructions Not Included (2013), a fish-out-of-water comedy drama about a single father from Mexico raising his daughter in the United States, and Under the Same Moon (2007), a melodrama which shows the quest of a young boy trying to arrive in California from Mexico in less than a week so that he can be reunited with his mother. Focusing on the representations of the parent-child relationship in the context of immigration that are presented in these films, this...
Show moreThis thesis analyzes the films Instructions Not Included (2013), a fish-out-of-water comedy drama about a single father from Mexico raising his daughter in the United States, and Under the Same Moon (2007), a melodrama which shows the quest of a young boy trying to arrive in California from Mexico in less than a week so that he can be reunited with his mother. Focusing on the representations of the parent-child relationship in the context of immigration that are presented in these films, this thesis addresses the debate between globalization and nationalism. The thesis analyses the films' representations of globalization, using the theoretical framework of Arjun Appadurai's "scapes" which postulates that there are five flows which enable people, ideas, and finances to cross political and ideological boundaries. Specifically, this thesis analyzes the implications of these representations for transnational communities and the development of cultural identity. Accordingly, this thesis also demonstrates how the representations of the parent-child relationship are effectively used to illuminate several aspects of immigrant and diaspora cultural identity using the theory of cultural identity of Stuart Hall to support this perspective. Finally, this thesis concludes by applying this analysis to demonstrate what role nationalist ideologies and politics play in the fracture of families, and to demonstrate the ineffectiveness of institutional attempts to curb or control forces of globalization based on the representations in the films.
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Title: The search for the broken windows tipping point : a dose-response propensity score assessment of the relationship between disorder and violent crime
Creator: Podges, Alaina De Biasi
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Wilson and Kelling (1982) provide a simple instruction for the implementation of order-maintenance policing: direct limited police resources to the broken windows tipping point. In doing so, they imply a certain functional form of the relationship between disorder and violent crime. That is, Wilson and Kelling's (1982) description of the tipping point suggests that the disorder-crime relationship is best captured as a threshold effect. If this is indeed the case, then a proper test of the...
Show moreWilson and Kelling (1982) provide a simple instruction for the implementation of order-maintenance policing: direct limited police resources to the broken windows tipping point. In doing so, they imply a certain functional form of the relationship between disorder and violent crime. That is, Wilson and Kelling's (1982) description of the tipping point suggests that the disorder-crime relationship is best captured as a threshold effect. If this is indeed the case, then a proper test of the validity of broken windows theory should accommodate nonlinearity. To this end, this study empirically examined the functional form of the relationship between physical disorder and violent crime rate in Detroit, Michigan utilizing a dose-response propensity score methodology. To facilitate its analysis, this study utilized block-group level data on physical disorder, violent crime, as well as socioeconomic and land use characteristics from the Detroit Police Department's record management system, Motor City Mapping project, and Census. Despite its comprehensive analysis, the functional form of the disorder-crime relationship remains unclear. That being said, the bulk of the evidence favors a nonlinear relationship, with partial support for Wilson and Kelling's (1982) interpretation of the broken windows tipping point. Several directions for future research are identified in an effort to spur the cultivation of this undeveloped avenue of research.
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Title: The systemic and regional hemodynamic changes responsible for 5-ht7 receptor mediated hypotension
Creator: Seitz, Bridget Mahon
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Serotonin (5-hydroxytrypamine; 5-HT) is known to cause complex dose-dependent effects within the cardiovascular system by altering vascular resistance and arterial pressure resulting in pressor or depressor outcomes. Increased circulating levels of 5-HT has been reported in chronic cardiovascular diseases. Therefore, it is important to understand the mechanisms by which 5-HT regulates cardiovascular system function under chronic conditions. Previous work in our laboratory found low doses of...
Show moreSerotonin (5-hydroxytrypamine; 5-HT) is known to cause complex dose-dependent effects within the cardiovascular system by altering vascular resistance and arterial pressure resulting in pressor or depressor outcomes. Increased circulating levels of 5-HT has been reported in chronic cardiovascular diseases. Therefore, it is important to understand the mechanisms by which 5-HT regulates cardiovascular system function under chronic conditions. Previous work in our laboratory found low doses of infused 5-HT causes a sustain fall in arterial pressure. The focus of my work was to understand the hemodynamic mechanisms that cause 5-HT-induced hypotension. A significant finding from my work was determining the activated 5-HT7 receptor is essential in mediating the chronic fall in arterial pressure with low doses of 5-HT. Rats lacking a functional 5-HT7 receptor (pharmacologically or genetically removed) resulted in no 5-HT-induced observed depressor response. At the systemic hemodynamic level, a decrease in total peripheral resistance (TPR) during 5-HT infusion was the result of an elevation in skeletal muscle blood flow mediated by the 5-HT7 receptor, which was measured with Doppler flow probes. Additionally, administration of 5-HT infusion relaxed splanchnic veins, via 5-HT7 receptor stimulation, when measured using novel imaging methodology. An increase in vascular capacitance from splanchnic venodilation is expected to affect arterial pressure by decreasing stroke volume (SV) and cardiac output. However, both SV and CO were elevated from the start and throughout the duration of 5-HT infusion, indicating that changes in vascular capacitance were unlikely to contribute to chronic 5-HT-hypotension. Previous evidence suggested chronic (but not acute) 5-HT-induced hypotension was dependent on activation of nitric oxide synthase. However, the magnitude of the pressor response to a nitric oxide synthase inhibitor was not significantly different between the control or 5-HT infused groups, concluding 5-HT-induced nitric oxide synthase may not be contributing. Collectively, my work provides insight into the unique cardiovascular pharmacology of the 5-HT7 receptor, a member of the 5-HT receptor family whose chronic cardiovascular effects have been little studied up to now. Future work should include: characterizing the impact of 5-HT7 receptor activation by endogenous 5-HT on chronic cardiovascular diseases such as hypertension and heart failure; and evaluating whether it is possible to capitalize on the unique cardiovascular effects of 5-HT7 receptor stimulation for therapeutic purposes.
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Title: The thrombospondin-CD47 axis in skeletal fracture biology
Creator: Zondervan, Robert Louis
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Skeletal fractures are one of the most common traumatic injuries. While the majority of fractures go on to heal, the incidence of fractures progressing to delayed- or non-union remains a significant concern. Fracture healing and vascularization are closely linked through angiogenic-osteogenic coupling, which regulates the biology of bone development, homeostasis, and repair. Enhancing vascularization by disruption of anti-angiogenic pathways could be a potential therapeutic to improve...
Show moreSkeletal fractures are one of the most common traumatic injuries. While the majority of fractures go on to heal, the incidence of fractures progressing to delayed- or non-union remains a significant concern. Fracture healing and vascularization are closely linked through angiogenic-osteogenic coupling, which regulates the biology of bone development, homeostasis, and repair. Enhancing vascularization by disruption of anti-angiogenic pathways could be a potential therapeutic to improve fracture healing. Thrombospondins (TSPs) are an important class of anti-angiogenic molecules that are produced by mesenchymal cells in the fracture callus. While implicated in regulation of angiogenesis, the TSP interactome is complex and includes over 83 unique ligands. A dominant anti-angiogenic mechanism of TSP1 and TSP2 is believed to be through interaction with cluster of differentiation 47 (CD47), a ubiquitously expressed integrin-associated penta-transmembrane protein that also plays an important role in regulation of cell cycle and homeostasis of the immune system. The purpose of this research is to define the spatiotemporal expression of TSP2 during fracture healing, and to describe disruption of the TSP-CD47 axis in skeletal fractures. A new method to generate physiologically relevant fractures and improve experimental rigor is also described. TSP2 spatiotemporal expression in skeletal fractures was studied using TSP2 green fluorescent protein reporter (TSP2-rep) mice. TSP2 is expressed in the periosteum of uninjured diaphyseal bone. Expression of TSP2 decreases immediately after fracture and then increases in undifferentiated regions of the early fracture callus. As mesenchymal stem cells (MSCs) differentiate to become chondrocytes, TSP2 expression is lost. Immunophenotyping by flow cytometry confirms that the majority of TSP2 expressing cells are MSCs. In vitro assays demonstrate all adherent and colony forming cells express TSP2, but that the non-adherent cells are TSP2 negative. The effect of disrupting the TSP-CD47 axis on fracture healing was studied using TSP1-null, TSP2-null, CD47-null, and wildtype (WT) mice. Disruption of the TSP-CD47 axis has a variable effect on callus morphology depending on whether TSP1, TSP2, or CD47 is absent. TSP2-null mice show accelerated intramembranous bone formation. TSP1-null and CD47-null mice show an opposite callus phenotype of reduced bone volume and bone mineral content relative to TSP2-null mice. To focus on the downstream receptor rather than the thrombospondin molecule, disruption of CD47 was studied in the context of ischemic fracture healing using CD47-null mice and mice treated with a CD47 disrupting morpholino. Loss of CD47 limits recovery of perfusion after ischemia relative to WT mice. CD47-null and morpholino-treated mice show reduced ischemic callus bone volume and bone mineral content. Mesenchymal stem cells (MSC) from CD47-null mice exhibit decreased cellular proliferation and colony formation. Loss of CD47 also downregulates expression of stem cell genes and limits entry into S phase of the cell cycle. The TSP-CD47 axis is a potent regulator of cell homeostasis and has potential for therapeutic development; however, because of cell and context specificity, therapeutics should be cautiously developed and the potential for diverse off-target effects considered.
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Title: The use of waste from orange juicing for food packaging applications
Creator: Fehlberg, Jack Alan
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Utilization of orange juicing waste (OP) as a filler material within a polymer matrix can add value to this agricultural waste and reduce dependency on non-renewable resources. This study aims to study the impact of OP filler's physical characteristics including size, loading, and retention or removal of zest on the properties of linear low density polyethylene (LLDPE) and to produce LLDPE/OP films by blown-film extrusion. LLDPE/OP sheets with zest exhibited decreased thermal stability,...
Show moreUtilization of orange juicing waste (OP) as a filler material within a polymer matrix can add value to this agricultural waste and reduce dependency on non-renewable resources. This study aims to study the impact of OP filler's physical characteristics including size, loading, and retention or removal of zest on the properties of linear low density polyethylene (LLDPE) and to produce LLDPE/OP films by blown-film extrusion. LLDPE/OP sheets with zest exhibited decreased thermal stability, larger OP agglomerates, worsened dispersion, and darker yellower colors and can act as UV- and light-absorbers. Larger OP particles increased air bubble formation, decreased mechanical properties, worsen dispersion, and produced darker yellower composites. Higher OP loadings resulted in LLDPE/OP composite sheets that have darker yellower color, decreased mechanical properties, and increased the size of OP agglomerates, as well as improved distribution and worsened dispersion. LLDPE/OP sheets that had properties most like neat LLDPE were sheets containing OP without zest and smaller particles sizes. This OP was used to determine maximum OP loading for LLDPE/OP films produced by blown-film extrusion. The LLDPE/OP films were subject to a sensory similarity triangle test and a comparison of package acceptance when different OP loading was used. This study found no difference in sensory qualities of bread when packaged in LLDPE/OP to neat LLDPE films. OP loading did not influence consumer perceptions of overall liking, appearance, surface roughness, color, or smell when LLDPE/OP films with 5 and 11.5% OP loadings were compared. This study demonstrates that OP waste can be converted and physically modified into a usable filler for plastic films for food packaging applications without altering the quality of the food product.
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Title: The vector field method and its applications to nonlinear evolution equations
Creator: Abbrescia, Leonardo Enrique
Date: 2020
Collection: Electronic Theses & Dissertations
Description: The vector field method was introduced in the 1980s by Sergiu Klainerman to analyze the decay properties of the linear wave equation. Since its historical debut, the vector field method has been at the forefront of several breakthrough results including the global stability of Minkowski space, the dynamical formation of black holes, and shock formation in 3D compressible fluids.This work showcases how the vector field method can be used in a systematic way to derive a priori estimates for...
Show moreThe vector field method was introduced in the 1980s by Sergiu Klainerman to analyze the decay properties of the linear wave equation. Since its historical debut, the vector field method has been at the forefront of several breakthrough results including the global stability of Minkowski space, the dynamical formation of black holes, and shock formation in 3D compressible fluids.This work showcases how the vector field method can be used in a systematic way to derive a priori estimates for nonlinear evolution equations. For nonlinear dispersive equations, these estimates can be married to the decay properties enjoyed by the solutions to derive quantitative asymptotics. This is done in this work through the lens of three concrete problems: a nonlocal kinetic model, the wave maps equation, and the relativistic membrane equation. For the kinetic model, the vector field method is paired with dispersive decay properties of the spatial density to prove global wellposedness of small data. This can be interpreted physically as "stability" of the trivial solution. For the wave maps equation, a stability result is proven for a "non-trivial" ODE geodesic solution. For the relativistic membrane equation, the vector field method is used to prove stability of large simple-traveling-waves. For the wave map and membrane equations, we intimately use several structural properties known as null conditions that preclude singular behavior.
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Title: The water-energy-food nexus assessments of carbon neutral efforts
Creator: Xie, Yachen
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Efforts toward carbon neutrality are crucial for humans' well-being and the environment. Currently, two main ongoing carbon mitigation efforts are enhancing carbon sequestration and reducing carbon emissions. However, there are debates regarding the tradeoffs of these two efforts' related policies and action plans. This dissertation investigates and assesses the tradeoffs of carbon neutral efforts from a WEF nexus perspective. Three typical efforts were selected as assessment targets to...
Show moreEfforts toward carbon neutrality are crucial for humans' well-being and the environment. Currently, two main ongoing carbon mitigation efforts are enhancing carbon sequestration and reducing carbon emissions. However, there are debates regarding the tradeoffs of these two efforts' related policies and action plans. This dissertation investigates and assesses the tradeoffs of carbon neutral efforts from a WEF nexus perspective. Three typical efforts were selected as assessment targets to answer the overarching question of how carbon neutral efforts would affect the water-energy-food (WEF) nexus. The Chinese conversion of cropland to forestland program (CCFP) is representative of carbon sequestration. The hydropower development in MRB is an example of the energy transition to reduce emissions. The coal power industry is the coupling effort of energy transition and carbon capture, utilization, and storage (CCUS) applications in reducing carbon emissions. This dissertation consists of three main chapters, each corresponding to a journal article to address the three assessment targets. In Chapter 2, I evaluated the accomplishment of CCFP in China and its WEF nexus tradeoffs by applying remote sensing images from 2001 to 2019. The WEF assessment includes the transition matrix generation and the water yield calculation of the converted cropland and irrigation land. Indices related to WEF systems are also considered. In Chapter 3, a diagnostic approach with ten indicators was developed to assess the unilateral change's impacts on the WEF nexus. Using the diagnostic method, I provided statistical evidence of the benefits and tradeoffs of water, energy, food, economic prosperity, and the environment surrounding hydro dams in the Mekong River Basin. In Chapter 4, a scenario-based, life cycle coal power production assessment tool was proposed. By evaluating three portfolios or scenarios, the tradeoffs between reducing coal power production and CCUS application were revealed. This dissertation has successfully assessed the primary tradeoffs of carbon mitigation efforts from the WEF nexus perspective. The three studies can be wrapped up and come to three major conclusions: 1) The cons of major carbon mitigation efforts on WEF nexus and local sustainability exist, but not as speculated, especially for the CCFP and the hydropower dam construction. 2) The carbon neutral policies in China can accomplish their goals if adequately implemented. 3) The adaptive equilibrium between the CCUS application and coal power production reduction in China is crucial and needs to be better planned. The dissertation can enrich the carbon neutrality debate and fill gaps in the current literature on WEF nexus tradeoff studies on carbon mitigation by providing a remote-sensing approach and detailed coal modeling tools. The assessment tools proposed in Chapters 3 and 4 can be widely used by policymakers to understand better the tradeoffs regarding sustainability and WEF nexus in carbon neutral efforts.
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