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  • An Examination of Peer-to-Peer Scaffolding as Metacognitive Support for Learning

    Wen, Wen; Castek, Jill; Teaching, Learning, and Sociocultural Studies, University of Arizona (InTech Open, 2023-12-09)
    This descriptive study examines peer-to-peer scaffolding implemented in an undergraduate, online digital literacies course for future educators. It identifies the different features of students collaboration processes and how these processes function as peer scaffolding to support their learning. Analyses of students’ collaborative dialog and reflections on their collaboration processes. By analyzing dialog, this study examines how collaborative discussion that is high quality can act as a form of peer-to-peer scaffolding that encourages metacognition. Peer-to-peer scaffolding not only provides just-in-time support, but also triggers students’ regulation thus helping them to refine their understanding and enhance self-awareness of their learning processes. Findings suggest that productive collaboration can serve as a useful means of peer-to-peer scaffolding marked by five specific features: 1) complementing each other’s expertise, 2) co-constructing knowledge, 3) collaborating to problem-solve, 4) encouraging reciprocal support, and 5) triggering regulation. Findings further explore students’ perspectives on collaboration. Students felt they benefited from peer-to-peer collaboration when the collaboration yielded the development of new ideas and understanding, offered support for problem solving, and provided opportunities for self-reflection. These markers of quality collaboration assisted students in achieving their learning goals. Recommendations outlined in this chapter offer guidance for educators by describing ways to promote productive collaboration when designing and implementing instruction.
  • Platform and Reagent Optimization Towards Detection of PFOA With a Simple Lateral Flow Assay

    Yoon, Jeong-Yeol; Thomas, Chloe Thomas; Farrell-Poe, Kitt; Hall, Caitlyn (The University of Arizona., 2024)
    Current methods to detect PFOA in drinking water require expensive, specialized equipment and trained operators. This research builds on previous research with the goal of creating a low-cost flow rate based microfluidic assay to test water for PFOA. The aims of this research include creating a platform for repeatable capillary flow rate-based testing and to determine the optimal reagents that interact with PFOA. Utilizing System Automated Loading for Sample Analysis (SALSA), the platform achieved greater consistency within individual chip channels and across multiple chips, evidenced by reduced standard deviation when compared to traditional pipetting techniques. Additionally, the platform demonstrated improved k-value consistency over successive uses relative to manual pipetting. The research also evaluated seven reagents for their effectiveness in detecting perfluorooctanoic acid (PFOA) in deionized water samples. Of these reagents, glutamine and L-lysine showed no statistically significant differences between PFOA-spiked samples and controls, indicating they may not significantly alter k-values for further assay development. In contrast, larger proteins such as bovine serum albumin (BSA) and lysozyme yielded promising results for PFOA detection. BSA displayed linear detection within the range of 100 ag/µL to 1 pg/µL PFOA, enabling approximate concentration measurement. This study identifies five reagents—BSA, lysozyme, myoglobin, glycine, and L-aspartic acid—as suitable for PFOA detection in water samples using a flow rate-based assay. The potential for further refinement of the assay towards cost-effectiveness and specificity, as well as the application of machine learning for enhanced data analysis, is highlighted. In initial ML trails using XGBoost, samples spiked with PFOA were differentiated from a DI control with 95% accuracy. Notably, the SALSA platform provides a viable solution for consistent chip loading in various flow rate-based assays, offering rapid performance and cost-efficiency without the need for target-specific antibodies.
  • Organic Phosphorus Compound Class Utilization by Marine Microorganisms in the Amazon River Plume

    Duhamel, Solange; Feldmann, Isabella Katarina; Charest, Pascal; Russell, Joellen (The University of Arizona., 2024)
    Dissolved marine phosphorus (P) consists of inorganic P (essentially phosphate, Pi) and organic P (DOP), encompassing P-esters, P-anhydrides, and phosphonates. Marine microorganisms use DOP compounds as a source of P, particularly in regions where Pi is scarce, though it is unclear which bond classes of DOP are preferentially utilized by natural microbial assemblages. Here we explored the potential microbial utilization of different DOP compounds at three stations with background Pi concentrations ranging from 50 to 70 nmol L-1, along the Amazon River Plume. We carried out seawater incubations by adding 20 µmol L-1 DOP as either adenosine monophosphate (AMP, P-ester bond), 3-polyphosphate (3PP, P-anhydride bonds), adenosine triphosphate (ATP, containing both P-ester and P-anhydride bonds), or methylphosphonate (MnPh, a phosphonate). Our results showed that most of the added AMP and ATP were hydrolyzed in 48 hours, as evidenced by a decrease in DOP concentrations and an increase in Pi concentration amounting to approximately 18 µmol L-1. These compounds were hydrolyzed by microbial communities since we ruled out autohydrolysis based on stable DOP compounds concentrations measured in MilliQ control samples. In contrast, the hydrolysis of 3PP and MnPh was low or negligible. While recent studies in culture have demonstrated that some phytoplankton species can break down and preferentially use P-anhydrides, our results from natural samples suggest that the microbial community as a whole degrades P-esters in larger amounts. We found that picophytoplankton and bacterial communities both benefited from the hydrolysis of P-esters, specifically the AMP and ATP that were tested, resulting in increased cell abundance. The findings carry significance for both the bioavailability of marine DOP and the broader process of ocean nutrient recycling within dissolved organic matter.
  • Designing, Manufacturing, and Testing a Wind Gust Generator

    Shkarayev, Sergey V.; Nietzel, Kylar Joshua; Hanquist, Kyle; Krokhmal, Pavlo (The University of Arizona., 2024)
    A two-vane wind gust generator has been designed, manufactured, and tested at the Arizona Low-Speed Wind Tunnel at the University of Arizona to meet the regulations defined in the FAR and CS by the FAA and EASA respectfully. A gust generator is a necessary feature for a wind tunnel because the response of a system can be analyzed when it is introduced to specific gusts parameters. Wind gusts change the pressure distribution over a body and cause the greatest aerodynamic structural loads on an aerial vehicle. Commercial aircraft use gust load alleviation systems to alter the pressure distributions around their wings to ultimately reduce any stress on the root of the wing. So, testing these systems in a controlled wind tunnel environment is beneficial for their optimization. In addition, there is an increasing interest in air vehicles for planetary exploration with numerous rotor and fixed wing aircraft being proposed in light of the accomplishments from the Ingenuity helicopter. Therefore, to increase airframe reliability under varying environments, it is important to consider the aeroelastic effects because they affect the aerodynamic performance, maneuverability, and control of an aerial vehicle. Previous gains in literature determined the best possible configuration for a wind gust generator, which was a two-vane configuration, and also established a technique to improve the discrete gust profile. Theresearch throughout this paper was aimed at designing a wind gust generator to fit the dimensions in the wind tunnel, conducting hot-wire measurements to quantify the generated gust, enhancing the discrete gust profile, classifying the enhanced discrete gust, and creating an input to output algorithm to generate specific gusts for future models. Overall, this wind gust generator was capable of creating the “1-cos” gust profile modeled by aviation authorities and able to obtain governing equations for a servomotor input to gust response output relationship. This wind gust generator was designed for a motor frequency up to 20 hertz and a motor amplitude up to 20 degrees. The work presented in this thesis is for a maximum motor frequency of 10 hertz, a maximum motor amplitude of 10 degrees, and a maximum tunnel velocity of 25 m/s.
  • Mutation of RPA2 May Be Connected to Systemic Lupus Erythematosus

    Sweasy, Joann; Nelson, Mark; Smith, Yasmeen; Lybarger, Lonnie; Wilson, Justin (The University of Arizona., 2024)
    Systemic Lupus Erythematosus (SLE) is an autoimmune disease that affects multiple organ systems and is characterized by the production of autoantibodies (Kumar, Abbas et al. 2023). Disease injury is caused by antigen-antibody complex deposition and antibodies binding to various tissues. SLE is quite common with 20 to 150 cases per 100,000 in the united states; it primarily affects women with a ratio of 9:1 females to males (Kumar, Abbas et al. 2023, Schur and Hahn 2023). Many genetic associations have been made to SLE such as mutatedRPA2 which is single nucleotide polymorphisms that is enriched in SLE patients. Replication protein A (RPA) is a heterotrimer that binds ssDNA. RPA is involved with multiple pathways in the cell such as DNA repair and DNA replication (Byrne and Oakley 2019). The aim of this thesis was the characterization of the RPA genetic variant with the goal of determining if it was sufficient to induce a for SLE phenotype. The hypothesis of this project: the RPA2 (RPA32) genetic variant plays a functional role in the etiology of SLE. RPA2 genetic variant was created using CRISPR. The characterization of RPA was done through a series of experiment: anti-nuclear antibody staining, cytokine profiling, kidney histology, glomerular deposition, ELISA for total IgG and IgM, ELISA for ssDNA and dsDNA, and germinal centers in a mouse model. There was a significant difference found in the anti-nuclear antibody staining and the cytokine profiling comparing mice with wild type RPA2 versus a mutant allele. The anti-nuclear antibody staining showed significantly higher levels in the 6-month group of RPA2 mutant mice compared to wild type mice. In addition, significantly higher levels of ANA were observed in the RPA2 G15R/ R homozygous versus wild-type mice at 12-months of age. IL-6, IL-10, and IL-15 had the most change in cytokine levels between wild type and mutant mice. Data suggest there could be an association between RPA2 and the development of SLE. However further studies are warranted. In the future it will be important to look at other phenotypes related to SLE, such as in the skin and GI tract. It would also be good to try stressing the mice with different stressors such as UV light and viruses to see if that would give a stronger immunological response consistent with SLE.

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