Now showing items 1-20 of 15255

    • Elevated Fibroblast Growth Factor 23 Mediates Cardiac Fibrosis in the Setting of Chronic Kidney Disease

      Wilson, Jean M.; Crawford, Monique; Streicher, John; Runyan, Raymond (The University of Arizona., 2021)
      Background: CKD (chronic kidney disease) is a progressive disease with a global prevalence of 11-13% (Hill et al., 2016). CKD disrupts homeostasis resulting in large majority of patients with CKD also suffering from CVD (cardiovascular disease), with over 90% of CKD patients having cardiac fibrosis (Graham-Brown et al., 2017). FGF23, a phosphaturic hormone derived from bone, has been found to be elevated in patients with CKD and is associated with increased mortality in this patient population. Elevated serum FGF23 levels lead to LVH (left ventricular hypertrophy) and cardiac fibrosis, however, the mechanism by which fibrosis develops is unknown. We hypothesize that FGF23 mediates cardiac fibrosis by activation of the RAAS (renin-angiotensin-aldosterone-system), TGF-β (transforming growth factor-β), and wnt/β-catenin pathways in cardiac myocytes and fibroblasts. Methods:A literature review was conducted to identify the current literature on FGF23, CKD, cardiac fibrosis, RAAS, TGF-β, wnt/β-catenin and the molecular mechanisms leading to pathology. Search engines used were PubMed, Elsevier, NCBI (National Center for Biotechnology Information), University of Arizona Library, Google, and Wikipedia. Keywords included: CKD prevalence and mortality, bone and mineral metabolism, FGF23 mortality, angiotensin II (ANGII) and cardiac fibrosis, and phosphate homeostasis. Conclusion: In a series of steps, systemic FGF23 mediates cardiac fibrosis via non-conical signaling pathways by first activating the RAAS in cardiac myocytes. RAAS activation in cardiac myocytes increases ANGII expression. ANGII crosstalk with cardiac fibroblasts leads to activation of fibroblasts and TGF-β pathways. TGF-β and 5wnt3a/β-catenin in cardiac fibroblasts activate pro-fibrotic gene expression. TGFβ and wnt3a/β-catenin from cardiac fibroblasts crosstalk with cardiac myocytes to induce pro-fibrotic gene expression and augment RAAS signaling pathway, respectively.
    • Monitoring and Assessment of Heat Stress and Heat Strain in Hot Arizona Mines

      Momayez, Moe M.; Cordova Rubina, Veronica Amanda; Lutz, Eric E.; Waqas, Muhammad M.; Lee, Jaeheon J.; Reed, Rustin R. (The University of Arizona., 2021)
      Occupational heat stress is one of the main causes of health-related risks in the mining industry. Heat stress can cause heat strokes, heat exhaustion, hyperthermia and sometimes even death. Therefore, the importance of monitoring heat stress and using cooling technologies in a mine is critical to mitigating these occupational health risks. Heat stress is conventionally monitored using stress indices. The estimation of stress indices requires measuring dynamically changing parameters, which imposes a challenge to monitoring stress. Core body temperature (CBT) has proven to be a relevant proxy for heat stress. However, measuring CBT is an invasive technique that may not always be feasible. In the first part of this study, we identify two easily and non-invasively measurable physiological parameters: heart rate (BPM) and urine-specific gravity (USG). Further, we relate these parameters to CBT. We also investigate the dependence of these parameters on miners' physiological parameters, such as use of energy drinks and the body mass indices (BMI). Our findings show a strong correlation between CBT and heart rate (Pearson Correlation >0.4), rendering the latter as a useful tool to monitor heat stress. The intake of energy drinks shows causation to increase dehydration (p value=0.049). Furthermore, in the second part of this study, we investigate how to reduce the risk of heat stress in mine operators. In order to evaluate limiting factors, we examine the amount of heat absorbed by hardhats of different colors, where our findings are that white hardhats are best at absorbing minimal energy (15F less than black hardhats). Additionally, we study the performance of three commercial cooling vests and a combination set (i.e., evaporative cooling cap and sleeves) in reducing perceptual heat strain (23% of improvement in Physical Strain Alleviation wearing evaporative vest). We find that the overall perceived heat stress index of mine operators is considerably less with cooling devices.
    • Molecular Phylogeny and Revision of Species Groups of Nearctic Bombardier Beetles (Carabidae: Brachininae: Brachinus)

      Moore, Wendy; Ikagawa, Raine; McMahon, Michelle; Bogan, Michael (The University of Arizona., 2021)
      Bombardier beetles of the genus Brachinus Weber are notorious for their explosive defensive chemistry; when threatened, they aim a 100°C cloud of benzoquinones directly at an enemy. Despite ongoing research on their defensive chemistry and ecology, the group lacks a robust molecular phylogeny. In this study, three loci from both the mitochondrial and nuclear genome (COI, CAD, 28S) were used to reconstruct the phylogeny of Nearctic Brachinus and to test hypothesized relationships based on a previous study based upon morphological characters (Erwin, 1970). All molecular phylogenetic analyses recovered all species groups proposed by Erwin as monophyletic except for the fumans species group. We find that Erwin’s fumans species group is polyphyletic. In its place, we erect the following five species groups: cinctipennis, fumans (revised), galactoderus, phaeocerus, and quadripennis. External morphological characters were traced on the molecular phylogeny to identify potential diagnostic characters. Apomorphic characters were identified for two new species groups, the fumans (revised) and phaeocerus groups. We also expand the cordicollis group to include B. medius and the americanus group.
    • Enhanced Delivery of Antibody Therapy Using Focused Ultrasound in a Mouse Model of Parkinson’s Disease

      Trouard, Theodore P.; Murphy, Devin Patrick; Chen, Nan-kuei; Hutchinson, Elizabeth B. (The University of Arizona., 2021)
      Parkinson’s Disease (PD) is the second-most prevalent neurodegenerative disorder after Alzheimer’s Disease and affects 680,000 US adults over the age of 45 as of 2010 [Marras et al. 2018]. This disease results in a loss of dopaminergic neurons, specifically in the substantia nigra. PD has also been associated with the accumulation of toxic oligomeric variants of alpha-synuclein (-syn). Although there are several medications that can help manage symptoms for PD, there is no cure. We have successfully created antibody reagents that selectively target toxic -syn variants without binding to non-oligomeric forms of normal alpha-synuclein. However, the blood-brain barrier (BBB) is a major obstacle for drug delivery and treatment of PD due to its low permeability to foreign objects. Due to the size of the monoclonal antibody, it is unable to cross the BBB without transporter proteins or temporary disruption of the BBB. This antibody therapy is delivered using novel magnetic resonance guided focused ultrasound (MRgFUS) treatment, which transiently disrupts tight junctions between epithelial cells in the BBB, resulting in gaps large enough for the antibody therapy to cross the BBB. Results indicate that the BBB was successfully opened over multiple timepoints, and the procedure does not cause extensive tissue damage. The results also show that the targeted antibody selectively binds to toxic -syn in regions of the brain where the BBB has been temporarily disrupted. Future work includes longitudinal studies to determine if this treatment combination can delay disease progression or improve quality of life in murine models of Parkinson’s Disease.
    • Characterization of U(-V) Deposits in the La Sal District, UT and CO and their Relationship to Paradox Basin Fluid Flow

      Barton, Mark D.; Bos Orent, Eytan; Barton, Isabel F.; Hughes, Amanda N.; Hall, Susan M. (The University of Arizona., 2021)
      The tabular sandstone-hosted uranium (U) and vanadium (V) deposits of the La Sal district form a 1-3 km wide, 30-km long belt spanning the Utah-Colorado border. They exemplify one of the principal types of U(-V) mineralization of the Paradox Basin and encompassing Colorado Plateau. Building on previous work, new field, petrographic and geochemical data provide the framework for an updated district synthesis of La Sal and its place in the broader geological context. Ore is hosted in the uppermost fluvial sandstones of the Salt Wash Member of the Jurassic Morrison Formation and forms elongate orebodies up to 180 m long, 90 m wide, and 1 m thick. Sparse organic material, mainly in the form of coalified plant fragments, is present in the sandstones which are interbedded with finer-grained silty, muddy and calcareous units. Principal changes in the rocks include bleaching by removal or reaction of early diagenetic hematite, a feature that is coextensive with quartz overgrowths . Later formed were compositionally distinct carbonate cements, and reaction of feldspars to kaolinitic clays. Bleaching was prior to or contemporaneous with (or both) mineralization, which is restricted to bleached rocks. Petrography shows that ore minerals (uraninite, coffinite, and montroseite) at least in part predate growth of authigenic quartz cements, and were in turn followed by the formation of V-rich sheet silicates (which may reflect reaction of montroseite with quartz and other minerals), carbonates, and clay cements. Depositional features control where mineral growth occurred and include sedimentary structures (e.g., crossbedding), primary porosity, and the distribution of lithofacies in trends like the La Sal channel system. The thin section to district-scale observations suggest that mineralization reflects mixing of two fluids, as has been suggested in other Plateau deposits, or, alternatively as a reaction of oxidized fluids with a preceding exogenous reduced component caused by bleaching. Increasing evidence in this area and elsewhere in the Paradox Basin suggests a complex fluid history including a major role for hydrocarbon-bearing fluids in bleaching and localization of metals beginning at least as early as the Late Triassic.
    • Modeling and Emulation of Optical Networks for SDN Control

      Kilper, Daniel; Quraishy, Aamir Nasir; Pau, Stanley; Norwood, Robert; Fan, Linran (The University of Arizona., 2021)
      Today's telecommunications networks are facing increasing internet traffic demands for a variety of high data-rate applications including virtual reality (VR), video-conferencing, and high-definition (HD) video streaming. Optical networks are more efficient than wired and copper networks over long distances and high speeds, and thus have been a large contributor for increasing data capacities over the past several decades. Developments in optical fiber technologies have allowed optical networks to be manufactured at steadily lower cost per bit. However networks do not just need to handle larger traffic volumes, they also need to work with existing network architectures and accommodate traffic requests with different requirements. One method for addressing this challenge is Software Defined Networking (SDN). SDN separates the control and data-plane so the data management and control decisions are made by a central controller that direct information as need be. However, developing SDN systems for optical networks at scale is difficult because optical networks need to consider signal quality and nonlinear fiber impairment. Mininet-Optical is an optical network emulator designed to emulate a multi-layer optical network so network designers can develop SDN control algorithms. Mininet is an open-source tool for studying SDN but does not support optical networks. We developed an optical layer simulator that is integrated into Mininet Optical. We evaluated this approach using the open-source planning tool GNPy and showed strong agreement. We also developed an SDN control algorithm for provisioning optical networks with bandwidth variable transceivers (BVTs) and examined how the SDN controller responds to diurnal traffic. BVT technology has received attention from the SDN community because of its ability to change modulation formats to optimize network capacity and their performance depends on the quality of transmission. This adds an extra element of control that SDN controllers can use to respond to varying traffic conditions such as diurnal traffic patterns and respond to different traffic needs. In this thesis we discuss SDN control, BVTs, Diurnal traffic modeling, optical fiber transmission physics, and the mininet optical system. From this, we will examine SDN control for a network with BVTs handling requests from metro networks in residential and office areas with diurnal traffic. This work shows how BVTs operate in an SDN controlled network while responding to time-varying traffic, and show non-linear impairment induced switching for heavily-loaded traffic.
    • Postoperative Urinary Retention after Pediatric Orthopedic Surgery

      Hammer, Ronald P.; Kruer, Michael C.; Belthur, Mohan V.; Stull, Terrence L. (The University of Arizona., 2021)
      Background: Postoperative urinary retention is defined as an inability to void after surgery or the presence of a major residual volume after voiding that requires catheterization. Postoperative urinary retention prolongs hospital stay and often leads to bladder catheterization, which exposes patients to the risk of urinary tract infection. This study aims to describe the incidence of postoperative urinary retention among pediatric patients undergoing orthopedic surgery and to identify risk factors for this complication. Methods: The Pediatric Health Information System (PHIS) was used to identify children aged 1-18 years who underwent orthopedic surgery during 2012-2015. Collected from each patient’s record were demographic information, principal procedure during hospitalization, diagnosis codes for the hospitalization, the presence of neurologic/neuromuscular conditions and other complex chronic medical conditions, the total post-operative length of stay, and the presence of post-operative urinary retention. Results: There were 232,551 pediatric patients undergoing orthopedic surgery from 2012-2015 that met our inclusion criteria. There were 892 cases of postoperative urinary retention, for an overall incidence of 0.38%. The average length of stay for patients with postoperative urinary retention was 7.8 days compared to 1.7 days in those without. After adjusting for gender, race, and age, children with complex chronic neuromuscular conditions (OR 11.54 (95% CI 9.6-13.88), p = <0.001) and complex chronic non-neuromuscular medical conditions (OR 5.07 (95% CI 4.11 – 6.25 -), p = <0.001) had a substantially increased incidence of urinary retention. Surgeries on the spine (OR 3.98 (95% CI 3.28 - 4.82, p = <0.001) and femur/hip (OR 3.63 (95% CI 3.03 - 4.36), p = <0.001) were also associated with a substantially increased incidence of urinary retention. Conclusions: While the overall incidence of postoperative urinary retention in children undergoing orthopedic surgery is low, children with complex chronic neuromuscular conditions have substantially increased risk of experiencing this complication. In addition, complex chronic non-neuromuscular medical conditions and surgeries to the spine, hip, and femur also carry a notably increased risk for postoperative urinary retention. Clinicians should be aware of these risk factors and recognize that occurrence of postoperative urinary retention is likely to increase patient’s length of stay. Level of Evidence: Prognostic Level III KEY WORDS: Postoperative, urinary retention, pediatric orthopedics, surgery, risk factors.
    • Single High Dose Oral Vitamin D3 (Stoss Therapy) in Pediatric Patients Undergoing HSCT: A Proposed Solution to Vitamin D Deficiency During Transplant

      Mohanakumar, Thalachallour; Ngwube, Alexander; Sharma, Shalini; Adams, Roberta; Shub, Mitchell (The University of Arizona., 2021)
      Vitamin D deficiency remains common among pediatric patients undergoing hematopoietic stem cell transplant (HSCT) despite both aggressive and standard of care strategies. This study examined the safety and efficacy of single high-dose oral vitamin D therapy (Stoss therapy) for treatment of vitamin D deficiency in HSCT recipients. Patients ages 1 to 21 years presenting for HSCT were randomized to receive either Stoss regimen plus weekly/daily supplementation or standard of care, per US Endocrine Society guidelines. Among the total 48 subjects, 22 (46%) were randomized to Stoss and 26 (54%) to control arms. Baseline 25-hydroxyvitamin D (25-OHD) levels were insufficient/deficient in total of 34 (71%) patients, without difference between treatment groups. The Stoss regimen was well tolerated, and no toxicity was observed. At Day +30, mean 25-OHD levels were significantly higher (p=0.04) with Stoss (42.3 ± 12 μg/l) compared to controls (35.6 ± 14.3 μg/l), and a higher proportion of Stoss patients had adequate vitamin D levels than controls (85% vs 65%). Stoss therapy is a safe and efficacious treatment option for vitamin D deficiency in children undergoing HSCT and may achieve sufficient levels more rapidly than standard of care. This trial was registered at as NCT03176849.
    • Implication of IL-6 Neuroinflammation in the Context of Insomnia as a Risk Factor for Neurodegeneration

      Zarnescu, Daniela; McMullen, Haley; Fernandez, Fabian; Romanoski, Casey (The University of Arizona., 2021)
      Sleep is a complex and required physiological process that is important for the health and function of a person. Disturbances in sleep have been linked to neurodegenerative diseases, yet it is unknown through what mechanism insomnia may be playing a role in this pathology. Recently, there has been emphasis in the field implicating disrupted metabolite clearance during slow wave sleep (SWS) in neurodegenerative diseases. However, the context of inflammation, specifically the pro-inflammatory cytokine IL-6, a known mediator of sleepiness, may provide important insight into sleep’s role in neurodegenerative diseases.
    • Net Slip and Linkage Patterns of the Sevier-Toroweap Fault System

      Hughes, Amanda; Delisser, Terrance; Johnson, Roy; Sbar, Marc (The University of Arizona., 2021)
      The Sevier-Toroweap fault system is a 250+ km high-angle normal fault located in southern Utah and northern Arizona in the High Plateaus subprovince. It is one of three main normal faults that accommodate the strain concentrated on the boundary between the Basin and Range and Colorado Plateau in the Utah Transition Zone. As with all faults in the Transition Zone, the Sevier-Toroweap fault system trends N-S but has distinct bends in the fault trace that trend northwest or northeast. These characteristic changes in strike reflect the segmentation and growth history of the fault. Since fault linkage is reflected in a fault system’s net slip distribution, this study characterizes the net slip distribution along the Sevier-Toroweap fault system reveals fault linkage patterns which can improve our understanding of how this fault formed, its extent, and geometric segmentation that could impact the potential seismic hazards associated with it.Compiled surface geology and subsurface constraints were used to construct cross-sections using kinematic forward modeling techniques in order to evaluate the subsurface geometry of the fault and calculate displacement along the main trace of the fault system. Displacement constraints collected from these cross section, published USGS cross sections and maps, and other literature were compiled to produce distance vs. displacement plots. These plots demonstrate the segmentation of the Sevier-Toroweap fault system and help reduce uncertainty as to where the northern terminus of the fault system lies. The linkage history implied by variations in fault strike, locations of fault splays, and displacement gradients along strike suggest that there are three main segments of the fault, which are different than the fault sections commonly used to describe the fault in the existing literature. Additionally, the high displacements and lack of observed decrease in displacement at the northern extent of the mapped fault suggests that the northern terminus may extend over 100 km north of the northernmost continuously mapped trace of the fault system and into the Marysvale volcanic field where it is thought to continue but be obscured due to outcrop conditions and geologic complexity within the volcanic system. In light of these new observations and constraints on displacement, fault linkage, and subsurface geometry, potential earthquake hazards associated with this fault are then evaluated.
    • The Use of Co-Constructions in Russian TV and Radio Political Interviews (On the Example of Vladimir Pozner and Alexey Venediktov)

      Klimanova, Liudmila; Fomchenko, Anna; Leafgren, John; Ecke, Peter (The University of Arizona., 2021)
      The present study investigates the use of co-constructions (or sentences-in-progress) in Russian TV and radio political interviews. The author analyzed ten political interviews conducted by Russian journalists Vladimir Pozner (TV interviews) and Alexey Venediktov (radio interviews). The analysis demonstrated the following results. Co-constructions in political interviews serve several distinct purposes. They are used (1) to obtain necessary information, (2) to correct facts provided by interviewees, (3) to ask questions, (4) to establish contact with interviewees and maintain it during the interview, (5) to express agreement and affiliation, (6) to express disagreement and negative assessment, (7) to supply a forgotten word or string of words. The use of co-constructions is influenced by personalities of conversational participants. The results of the analysis showed that the frequency of occurrence of co-constructions on TV and radio interviews is the same. The study follows the analytical framework based on conversation analysis. Keywords: conversation analysis, co-construction, joint construction, sentence-in-progress, compound turn-constructional unit, radio interview, TV interview.
    • Progress Toward a Vacuum-Ultraviolet Raman Spectrometer to Detect Pathogens

      Milster, Tom D.; Dmitrovic, Sanja; Shelley, Jacob T.; McLeod, Euan (The University of Arizona., 2021)
      Rapid detection and identification of novel viruses, such as SARS-CoV-2, are critical to treat, isolate, or hospitalize those infected; and ultimately, to curb the spread of the virus. Diagnostic assays, such as quantitative reverse transcriptase polymerase chain reaction (RT-qPCR), are considered the gold standard for testing. However, these methods are labor-intensive and/or involve creating probe molecules specific to the virus. We propose Raman spectroscopy as an alternative method of detection, because samples can be efficiently used with a simple spectrometer configuration with measurements collected on the order of seconds, eliminating the drawbacks of RT-qPCR. Specifically, we are developing a vacuum-ultraviolet (VUV) Raman spectrometer using an incoherent excitation source that emits hydrogen Lyman-α (HLA) at 121.57 nm. Since HLA Raman spectroscopy has not been demonstrated in literature to date, this paper serves to justify the use of an HLA Raman excitation source. The main question posed throughout this work is, “Is achieving detectable Raman signal possible by using a 121.57 nm light source?” Through a literature review of other Raman spectroscopy work and our own experiments relating to source and camera optimization, it is concluded that achieving detectable Raman signal at 121.57 nm is indeed possible. In the future, we expect to produce consistent Raman spectra in samples. To achieve that goal, further efforts are needed in terms of maximizing source power and minimizing camera noise. Overall, we expect that HLA Raman spectroscopy will transform diagnostic medicine and several other industries through its powerful capabilities of detecting real-time infections and important health markers.
    • Experience Affects Honey Bee (Apis mellifera) Activity and Diet Preferences in a Controlled Environment

      Corby-Harris, Vanessa; Bronstein, Judith; Welchert, Ashley; Papaj, Daniel; Kacira, Murat (The University of Arizona., 2021)
      Research on the use of greenhouse pollinators other than bumblebees is of increasing importance as global climate change poses greater risk to field crops, and controlled environment agriculture (CEA) ensures some access to food out of season and during times of crop failures. Unlike many native or solitary pollinators, there are well established management systems for honey bees as outdoor crop pollinators and they are widely and often locally available. Despite this, little has been done to investigate the use of honey bees as greenhouse pollinators, in part due to anecdotal evidence that honey bee foragers are disoriented in the artificial environment and never return to their colonies. This apparent disorientation could be due to the greenhouse disrupting cues that honey bee foragers learn to use in navigating natural environments, such as the position of the sun, floral odors, and visual and tactile cues. There is evidence that individual experience can affect honey bee behavior, but how does experience in different environments affect honey bee activity, diet choice and learning in the greenhouse? The aim of the current study was to bring insights gained from lab studies into a larger context to move towards understanding patterns of honey bee behavior in greenhouse agricultural environments. To answer this question of how experience affects honey bee behavior, naïve colonies were maintained outdoors or in the greenhouse until bees were several days past foraging age. Colonies from each group were then moved to separate greenhouse or screened enclosures to observe foraging on artificially provided diets in each environment type. We observed bee activity at feeder arrays containing high- to low-value pollen and sucrose resources. The results generally suggest that the greenhouse environment encourages higher sucrose foraging activity, but for pollen foraging, activity depends on prior experience. Prior experience also affects preference for diets of different quality in the greenhouse but not in the screenhouse. Learning acquisition was not affected by the environment of prior experience. The environment of prior experience may be part of the reason honey bees appear disoriented in a greenhouse. Using naive honey bee colonies rather than outdoor experienced colonies could be a management strategy for achieving better pollination with honey bees in a greenhouse.
    • The Impact of Pitch Level Tracking Data and Catcher Receiving Skills on Strike Calls

      Watkins, Joe; LeBlanc, Cameron; Bedrick, Edward; Tang, Xueying (The University of Arizona., 2021)
      From the full season debut of PITCHf/x in 2007, advanced radar and optical tracking systems have significantly changed the way that Major League Baseball players have been evaluated. With that information, managers and front offices have ample amounts of information to make decisions in all aspects of the game. While baseball largely is focused on the batter and pitcher matchup, there is one aspect of a pitch where neither the batter nor pitcher have control, the decision of the umpire to call a ball or strike. In this thesis, we investigate the impact of the catcher on a pitch call. Our input variables are a variety of pitch information including pitch velocity, spin rate, and movement. To start, a baseline strike called probability is calculated using a logistic general additive model using the pitch location, batter hand, and pitcher hand. Using this information, we isolate the edge of the strike zone where the umpire decision is most uncertain. Using a generalized mixed effects binary model, we analyze the impact of the baseline strike called probability using pitch data as fixed effects and catcher and umpire as random effects. Originally, our pitch level data included a categorical pitch type variable, which classified the data set’s fourteen pitch types into fastballs, sliders, curveballs, and changeups. Collinearity issues of pitch type against pitch velocity, spin rate, horizontal movement, and vertical movement led us to remove these categorical variables to create a simpler but still effective model. From this model, each pitch level variable has a statistically significant impact on the probability of a strike call, including a negative relationship with pitch velocity. Catchers and umpires have similar impacts on the probability of a called strike. Lastly, this model was assessed on pitches that land at each of the four edges to investigate differences in model estimates. Horizontal break changes with each side and the top of the zone leads to higher variability in umpire performance while the bottom has the opposite effect. The limitations of the methods re- strict how well we can understand the scale of the individual performances of each catcher and umpire. For future research, I would consider alternative and additional methodologies and explore other situational factors like score and count.
    • A Qualitative Study of Culture, Identity, and Belonging Among Second Generation Brazilian Immigrants Living in Paraguay

      Vasquez-Leon, Marcela; Thalenberg, Achishai; Carvalho, Ana M.; Retis, Jessica (The University of Arizona., 2021)
      The ethnic demographic characterizing much of Paraguay’s Eastern Border Region (EBR) is heavily comprised of Brazilian immigrants and their now Paraguayan-born descendants. Often referred to as “Brasiguayos” - these Brazilian immigrants reside in both inclusive migrant communities dominated by Brazilian culture and in culturally mixed cities where they attend school, do business, prosper, and co-exist alongside Paraguayans. Exploring the notion of a uniquely “Brasiguayo” identity, this qualitative study seeks to understand the different cultural settings that help construct the identity of second-generation Brasiguayos living in mixed communities. Employing a framework based on transnationalism, hybridism, and cultural citizenship, this project examines the attitudes second-generation Brasiguayos hold towards their citizenship, belonging, and civic engagement in Paraguay. It seeks to answer questions related to the different cultural spaces comprising the national identity of second-generation Brasiguayos; their understanding of the term Brasiguayo and of what it means to have a bicultural identity; their perception of the challenges of cultural integration into Paraguayan mainstream society; and their views regarding the future of the Brasiguayos in Paraguay.
    • Worm Paparazzi – A High Throughput Lifespan and Healthspan Analysis Platform for Individual Caenorhabditis elegans

      Sutphin, George; Freitas, Samuel; Trouard, Ted; Bilgin, Ali; Paek, Andrew; Sutphin, George (The University of Arizona., 2021)
      Aging is a near ubiquitous phenomenon prevalent across evolutionary lineages from single-celled organisms to humans. Natural aging is characterized by a progressive deterioration in cellular and tissue function. Age is the primary risk factor for the many of the most prevalent diseases and pathological conditions today. Lifespan and healthspan measurements are the gold standard phenotypes for aging research, integrating the influence of many complex molecular processes into a set of easily measurable physiological metrics. Due to the number of environmental, genetic, and phenotypic inputs, a high degree of variation is present between individuals within a given population. The roundworm Caenorhabditis elegans is among the most common model systems used to study aging, because of its short lifespan (~3 weeks), simplicity to culture in the lab, and availability of powerful genetic tools. Lifespan is traditionally measured through population-level survival assays counted by hand on petri plates containing solid nematode growth media (NGM) and seeded with a bacterial food sourec, with each plate containing a sample of a few dozen animals to represent a population. These studies can give an accurate measure of aging within restricted populations under experimental conditions but require many hours of human attention. The amount of resources required to create statistically well-powered data is inefficient in terms of cost, time, and labor. In order to alleviate this research bottleneck, different mechanical systems have been proposed and implemented, each with their own advantages and disadvantages. Robotic systems have been created that can recapitulate manual lifespan results. Most of these systems either rely on population-level assessment of lifespan, require manual input during data processing, or necessitate maintaining worms in a liquid culture environment. Liquid culture causes C. elegans to swim continuously, placing the animals into a stress state that can change the molecular processes that influence aging. Thus, by changing the environmental context, new discoveries in liquid culture cannot be directly compared to the majority of previous work on C. elegans aging conducted on solid culture. Here I describe Worm Paparazzi, a novel analysis system designed to automate lifespan and healthspan measurement for individual roundworms cultured on solid media. This system uses the WorMotel™ (Churgin et al. 2017) a 240-well plate constructed from polydimethylsiloxane (PDMS) that isolates individual C. elegans on solid media under conditions similar to traditional manual lifespan assays. By leveraging the characteristics of the WorMotel™, creating supporting robotics, and building a custom analysis architecture, the Worm Paparazzi analysis system is able to combine the accuracy of human lifespan screeners—while removing one source of human bias—with the high-throughput capabilities of a machine-based system for an individualized insight into C. elegans lifespan and healthspan assays, thereby providing researchers with a new, powerful tool to study the macroscopic result of lifespan and healthspan assays.
    • Discontinuous Galerkin Methods For One And Two Dimensional Schr odinger Equations

      Brio, Moysey; Aktepe, Omer; Kunyansky, Leonid; Sanchez- Vizuet, Tonatiuh (The University of Arizona., 2021)
      The aim of this study is to solve linear and nonlinear Schrödinger equationswith periodic boundary conditions. To that purpose, we used discontinuous Galerkin method. The optimal order of accuracy for the discontinuous Galerkin method was found to be $O(h^{k+1})$ where $h$ is the mesh spacing and $k$ is the degree of the polynomial expansion used in the study. Our methods showed that discontinuous Galerkin method is reliable and powerful.
    • In Vitro Bioaccessibility of Arsenic in Arsenopyrite

      Chorover, Jon; McKenna, Anissa Yvette; Root, Robert; Abrell, Leif; Schaap, Marcel (The University of Arizona., 2021)
      Contamination from legacy sulfide mine tailings is a persistent problem due to elevated concentrations of toxic metal(loid)s, e.g., arsenic. In semi-arid regions, such as the Southwestern US, dry climate and lack of vegetative cover create conditions for off-site transport of tailings as fugitive dusts. This poses a considerable risk to proximal communities who can experience exposure through incidental inhalation and ingestion of particulate matter. Generally, arsenopyrite (FeAsS) is the parent rock mineral for arsenic at many sulfide ore derived mine tailings sites. Initial in vitro bioaccessibility (IVBA) experiments – conducted under anoxic conditions, with rigorous cleaning of oxidized surficial precipitates, and utilizing HPLC-ICP-MS for aqueous speciation analyses – suggested that arsenopyrite reacted in synthetic gastric fluid to release arsenate (AsV) to solution. The apparent oxidation of As during FeAsS dissolution was unexpected, and could reflect the co-elution of thioarsenicals with pentavalent arsenate in HPLC-ICP-MS. Thus, a new set of experiments were conducted using synthetic thioarsenical standards, testing their stability in the development of new HPLC-ESI-MS/MS and HPLC-ICP-MS methods. Relevance of this work is supported by the fact that there is little known about the aqueous stability of thioarsenical compounds during FeAsS dissolution, despite their high toxicity.
    • Toxic Metal(loid) Lability in Response to Phytostabilization: A Mesocosm Study

      Chorover, Jon; Buchanan, Nicholas; Root, Robert; Dontsova, Katerina (The University of Arizona., 2021)
      Previous studies have shown that application of phytostabilization at the Iron King Superfund site resulted in large reductions in fugitive toxic dust emissions as well as a shifting mine tailing biogeochemical regime. In this study, the impact of this shifting biogeochemical regime on contaminant speciation and mobility were investigated throughout the phytostabilization process on the mesocosm scale. Selective sequential extractions coupled with X-ray spectroscopic and scattering characterization were utilized to monitor contaminant speciation in this study. Planting buffalo grass into compost amended tailings as a phytostabilization treatment resulted in minor enrichments of jarosite and ferrihydrite in the upper section of the tailings profile. Development of these host phases also enriched their bound fractions of As and Pb. Water soluble zinc was almost entirely flushed out of the tailings following this treatment, indicating acidic conditions in the tailings throughout the phytostabilization. The quail bush treatment resulted in extensive weathering of Fe in the tailings throughout the profile. Along with enriched ferrihydrite and jarosite, inner sphere complexed As was enriched throughout most of the tailing profile, increasing the bioaccessibility risk of these tailings. Zinc leaching, on the other hand, was limited by this treatment through the sequestration of water soluble zinc. Indicating more basic pH conditions in the tailings, despite further Fe weathering. The Risk Assessment Code, or RAC, was used in this study to quantify bioavailable metal(loid) species. Tailings treated with irrigation only, composting and irrigation, and buffalo grass phytostabilization resulted in decreased or similar RAC values for As in the untreated tailings. The quail bush plant treatment resulted in a roughly 2%-3% increase in this value. The phytostabilization treatments were successful for fugitive dust emission reduction, but this work indicates that irrigation, composting, and the two plant treatments impact metal(loid) lability and ultimately the bioaccessibility of toxic metal(loid)s in these tailings.
    • The Role of Racial Microaggressions and Ethnic Racial Identity Affirmation on Academic Belonging Among Black and Latinx College Students

      Delgado, Melissa Y.; Toomey, Russell B.; Sarsar, Evelyn Danilova; Zeiders, Katharine H. (The University of Arizona., 2021)
      Racial microaggressions are subtle forms of racial discrimination experienced by marginalized groups during day-to-day interactions. Growing evidence suggests that these subtle experiences of racial discrimination negatively impact one’s psychological and physical well-being. Despite this work, however, few studies have explored the role of racial microaggressions in college students’ academic belonging. Alongside experiences of racial microaggressions, the current study also considered emerging adults’ethnic racial identity (ERI) affirmation, which refers to the positive attitudes and beliefs about one’s ethnic or racial group membership. ERI affirmation is an important construct for adolescents that has been shown to reduce and mitigate stressors, in some instances. To address limitations in the literature, the current study utilized a weekly diary design to examine how fluctuations in racial microaggressions relate to Latinx and Black emerging adults’ academic belonging and how ERI affirmation may mitigate the negative effects of racial microaggressions on academic belonging with peers, faculty, and administrators. Results indicated that week-to-week fluctuations in racial microaggressions were negatively associated with feelings of belonging with peers, but not with faculty or administrators. However, the average experiences of racial microaggressions on sense of belonging were positively associated with feelings of belonging with peers, faculty, and administrators. This suggests that even subtle forms of racial discrimination can impact one’s sense of belonging with others. ERI affirmation, however, did not mitigate the weekly association between racial microaggressions and academic belonging. College institutions must acknowledge that these subtle, yet impactful forms of discrimination, are still very prominent on college campuses and they have implications for emerging adults’ academic belonging.