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Differential Expression of MicroRNA MiR-145 and MiR-155 Downstream Targets in Oral Cancers Exhibiting Limited Chemotherapy Resistance
No full textBackground: New evidence has suggested that non-coding microRNAs play a significant role in mediating and modulating chemotherapy resistance, particularly among oral cancers. One recent study found that the expression of miR-145 and lack of miR-155 expression strongly correlated with a limited chemotherapy resistance to Cisplatin, 5-Fluorouracil and Paclitaxel , although the mechanism(s) responsible for these observations remain unidentified.
Methods: Using commercially available cell lines of oral squamous cell carcinoma (OSCC), RNA was isolated using phenol:chloroform extraction. The isolated RNA was converted into cDNA by reverse transcription and subsequently screened for the presence or absence of downstream targets of miR-145 and miR-155 using qPCR.
Results: The expression of miR-145 downstream gene targets (n=13) were analyzed in all OSCC cells. The expression pattern of three miR-145 gene targets could be correlated to the degree of chemotherapy resistance. In the least chemotherapy resistant cells (SCC15), altered expression of KCN and SRGAP2 and the absence of FAM135A expression were observed. This differential expression was unique to the SCC15 cells and not detected in any of the other OSCC cell lines.
Conclusions: These data strongly support that differential regulation of these three downstream targets is related to the chemotoxic sensitivity of the SCC15 oral cancer cell line. The potential involvement of these targets must be further investigated to determine how and whether mechanisms of these cellular pathways may be involved in the observed lack of chemotherapy resistance. These data may be important to design targets or treatments to reduce chemotherapy resistance and improve patient treatment outcomes
Investigating Controls on Temporal and Spatial Variation of Dissolved Uranium at Springs in Horn Creek Drainage, Grand Canyon National Park, Arizona, USA
No full textGroundwater is a critical resource in the Grand Canyon, providing water to local communities, millions of annual visitors, and ecosystems. One major concern for this critical resource is the potential for uranium contamination in conjunction with uranium mining efforts. Upper Horn Bedrock Spring (UHB) in the Horn Creek drainage of the Grand Canyon sits below the oldest uranium mine in the region, Orphan Lode mine. UHB spring contains the highest concentration of dissolved uranium in the region, eclipsing the Maximum Contaminant Level (MCL) set by the USEPA by an order of magnitude on average. This research and recent collaboration with the U. S. Geological Survey (USGS) provide further insight into the hydrogeochemical evolution of the groundwater within the drainage, with an emphasis on trying to understand the temporal and spatial variation of dissolved uranium within groundwater sampled in Horn Creek drainage. This thesis specifically investigates two environmental phenomena surrounding dissolved uranium in the drainage using stable isotopes, multivariate statistical analysis, inverse modeling in PHREEQC, and bivariate analysis. The first phenomenon is the relatively rapid change in dissolved uranium concentration as flow moves downgradient from Upper Horn Bedrock spring to Upper Horn Alluvium spring. Approximately 200 m apart, there is roughly an order of magnitude decrease in dissolved uranium between the two springs. Inverse modeling suggests that water-rock interactions could explain the observed change in uranium concentration if the mineral pyrite is present in trace concentrations along the flow path. Inverse modeling and multivariate analysis also suggest that mixing between UHB and a second spring, East Horn Creek – Battleship, could explain the observed change in chemistry. However, stable isotopes collected in 2013 do not support EHC-BS as a mixing partner. The second phenomenon investigated is the variable concentration of dissolved uranium at UHB over time. Twenty-two samples have measured the concentration of dissolved uranium at Upper Horn Bedrock spring across nearly two decades, with concentrations ranging from 151 ppb to 509 ppb. Results indicate that although there is no trend in dissolved uranium over time, there is a relationship between recent precipitation and dissolved uranium. Bivariate analysis comparing recent precipitation (up to 120 days prior to sample collection) and dissolved uranium indicates that wetter periods 9 to 10 weeks prior to sampling correspond to the lowest concentrations of dissolved uranium recorded since 2003. Drier conditions 9 to 10 weeks prior to sampling correspond to higher concentrations of dissolved uranium, however significant variation is present among these higher concentrations
Persisting Inequity: School Administrators’ Social Dominance Orientation and Disciplinary Practices
No full textEmpirical research has established that exclusionary discipline is applied to black students at a higher rate than white students for similar offenses, and that this disproportionality cannot be attributed to the severity or frequency of misconduct. Exclusionary discipline, which removes a student from the educational setting, poses significant challenges to academic and social well-being and introduces a host of proximal issues for black students. This dissertation draws upon Social Dominance Theory (SDT), which examines how beliefs aligned to existing hierarchies perpetuate discrimination and oppression, to explore how administrators\u27 anti-egalitarian beliefs and disciplinary practices influence the disproportionate application of exclusionary discipline towards black students in a large urban school district. Using an ordinary least square regression model, this study investigated data collected from high school administrators regarding their anti-egalitarian attitudes and disciplinary practices to predict relationships with discipline disproportionality. Results indicated that administrators\u27 anti-egalitarian attitudes positively correlated with the presence of exclusionary discipline gaps, particularly in the areas of alcohol, tobacco, and drug-related incidents, disruptive behavior, and bullying. Furthermore, disciplinary practices such as anti-suspension, preventative measures, and system approaches also showed significant correlations with exclusionary discipline gaps when controlling for anti-egalitarian attitudes. These findings suggest that disciplinary decisions are influenced by administrators\u27 beliefs in maintaining social hierarchies, contributing to the disproportionate discipline of black students. The study highlights the need for education systems to address discipline disproportionality as a systemic issue rooted in power dynamics and social hierarchies. By recognizing the role of school administrators in perpetuating inequities, educational institutions can implement strategies to promote equity, inclusion, and improved outcomes for all students
Lake Mead: A Living Museum
No full textLake Mead, the largest man-made water project in the nation and a prolific source of electricity, irrigation, and recreation for much of the western population, is currently experiencing a drastic transformation. Amid the ongoing water crisis parching the west, the once overflowing reservoir is consistently shrinking, descending into depths historically uncharted.
While serving as a bleak demonstration of climate change’s effects, the body of water is simultaneously assuming an alternative role that may be less apparent to the public. As water levels decline, Lake Mead is actively metamorphosing into a “Living Museum”, by gradually unveiling previously submerged artifacts. As a result, it is displaying pieces of the local and regional history that were formerly concealed by its watery domain. Lake Mead’s evolving identity has inspired further investigation into what the lake has been storing since its inception nearly a century ago. This creative thesis project adopts the format of an audio documentary, delving into the supplementary persona of Lake Mead and its surrounding areas. By weaving together an interdisciplinary collection of expertise surrounding Lake Mead, this endeavor will work to explore the concealed histories, cultural nuances, and the mysterious artifacts sprouting from the waters. By providing Lake Mead with an alternative narrative, this thesis aims to present a creative and compelling interpretation through which to observe the diminishing reservoir. In doing so, it provides a divergence from the predominant storyline shaped by the climate crisis
Assessment of Success Factors and Comparative Analysis of Public Private Partnership (P3) Project Performances Against Design-Build and Design-Bid-Build Project Delivery
No full textPublic-private partnerships (P3s) projects have gained widespread popularity in both developed and developing countries due to their ability to access new financing sources and shift specific project risks to the private sector. P3s has been an active area of research with a particular focus on the concept of Critical Success Factors (CSF). The growing interest and the diverse outcomes associated with P3s emphasize the need for a thorough investigation into the factors that contribute to successful P3 projects. This study focused on identifying the CSFs for P3 highway and building projects towards project objectives of achieving cost efficiency and schedule advantage using literature reviews and questionnaire survey. Additionally, the study aimed to conduct an empirical analysis by comparing cost and schedule performances of P3 projects with design-build (DB) and design-bid-build (DBB) highway and building projects. To collect data regarding critical success factors relevant to real projects in the United States, the research has employed a questionnaire survey. This survey was distributed to participants involved in P3 highway and building projects who provided ratings for the identified CSFs relevant to their respective projects. Furthermore, the study extended its data collection efforts to include DB and DBB highway and building projects of similar size and scope, to facilitate a comparative analysis enabling an assessment of cost and schedule effectiveness of these three project delivery methods. The study concluded that the P3 highway projects in the United States have better cost performance compared to DB and DBB projects. Similarly, P3 building projects exhibit better cost and schedule performance in comparison to DB and DBB projects while no statistically significant difference was found in schedule performances between P3 and DB projects. It is hoped that the research findings will assist the public owners to ensure the success of their future P3 endeavors, particularly in terms of cost and schedule performances. The study outcomes can hold potential in public and private sectors by providing insights into how specific critical factors can be applied to enhance the execution of P3 method in both highway and building construction projects
Online Learning for Acid-Fast Bacilli Detection in Histopathological Images
No full textThe acid-fast stain is frequently used for laboratory diagnosis of tuberculosis. It is a labor intensive task requiring thorough examination of extremely high-resolution images to pinpoint the presence of the mycobacteria. This paper presents a machine learning assisted slide image analysis tool with the aim of aiding histopathology professionals in the accurate diagnosis of tuberculosis in patients through the analysis of microscopic imagery. The proposed tool combines a digital whole slide image viewer with an online learning framework. We also conducted a survey of different state-of-the-art online learning methods, and found that MIR with pre-training has the best performance on the CIFAR-10 dataset
Disruption of the OsWRKY71 Transcription Factor Gene Results in Early Rice Seed Germination Under Normal and Cold Stress Conditions
No full textBackground
Early seed germination in crops can confer a competitive advantage against weeds and reduce the time to maturation and harvest. WRKY transcription factors regulate many aspects of plant development including seed dormancy and germination. Both positive and negative regulators of seed germination have been reported in many plants such as rice and Arabidopsis. Using a transient expression system, we previously demonstrated that OsWRKY71 is a negative regulator of gibberellin (GA) signaling in aleurone cells and likely forms a “repressosome” complex with other transcriptional repressors. Hence, it has the potential to impact seed germination properties. Results
In this study, we demonstrate that OsWRKY71, a Group IIa WRKY gene, appeared at the same time as seed-bearing plants. Rice mutants lacking OsWRKY71 have seeds and embryos that germinate earlier than wildtype controls. In oswrky71 aleurone layers, α-amylase activity was hypersensitive to stimulation by GA3 and hyposensitive to inhibition by abscisic acid (ABA). Early germination in oswrky71 intact seeds was also hyposensitive to ABA. Transcriptomic profiling during embryo germination and early post-germination growth demonstrates that OsWRKY71 influences the expression of 9–17% of genes in dry and imbibing embryos. Compared to wildtype embryos, the mutant transcriptomes have large temporal shifts at 4, 8 and 12 h after imbibition (HAI). Importantly, many genes involved in the ABA-dependent inhibition of seed germination were downregulated in oswrky71-1. This mutant also displayed altered expression of multiple ABA receptors (OsPYLs/RCARs) that control ABA signaling and the VP1-SDR4-DOG1L branch of ABA signaling that promotes seed dormancy. Association studies reveal an OsWRKY71-containing quantitative trait locus involved in low-temperature seed germinability, qLTG-2. Indeed, oswrky71 seeds germinated early at 15 °C. Conclusions
Rice Group-IIa WRKY transcription factor OsWRKY71 is a master regulator of germination that influences the expression of 9–17% of genes in dry and imbibing embryos. It is also most likely the primary candidate of low-temperature seed germinability QTL, qLTG-2. We propose that knockouts of OsWRKY71 can generate rice varieties with improved germination properties under normal or low-temperature conditions
The Effect of Encoding Strategies on Recognition Memory
No full textSuccessful memory decisions require distinguishing between true and false memories. VariouS strategies can be used to avoid false memories such as the Recall-To-Reject (R-R) strategy and the Distinctiveness Heuristic (DH). R-R involves rejecting false information by recalling correct information (I know this person is not Bob, because Bob has brown hair); while DH involves the rejection of false information due to failure to recollect expected information (I know I never met this person because I would remember if I had). The purpose of this study is to examine how these strategies affect recognition memory. In the present study participants were presented with a series of unrelated words at study, which were paired with either the word spoken out loud (word+spoken condition) or a colored image of the word (word+picture condition). The study task was completed under either Full-Attention (FA) or Divided-Attention (DA), the latter included completing an n-back task during encoding. At test participants completed a recognition memory test which required participants to determine if a word was old (studied) or new (unstudied). New items were either unrelated to the studied words or were very similar to previously studied items but differ in plurality. We expect the R-R strategy will be used more in the word+spoken condition under FA, and that DH will be used more in the words+pictures condition under DA. This study contributes to the understanding of how DH and R-R affect memory, and can provide more insight on which strategies aid in avoiding false memories.https://oasis.library.unlv.edu/durep_posters/1213/thumbnail.jp
Beyond the Waterfall: a Review of Project Management Methodologies in Stem
No full textProject management has been exercised from history\u27s early stages to concurrent practices today. It has evolved from the early stages of the Gantt chart and five primary principles to well-renowned project management methodologies such as Waterfall and Agile. This literature review focuses on comprehending four project management methodologies (Waterfall, Agile, Kanban, and Scrum), learning their criteria and frameworks, and their application in a specific STEM environment when applicable. This work reviews the recent research literature about these four methods. An overview of project management certificates and guidelines is covered as well. Waterfall is known to be a traditional method, having linear and sequential phases to complete a project. Agile, on the other hand, focuses on an iterative cycle while prioritizing customer involvement. Kanban and Scrum, being derivatives of the Agile methodology, focus on visualization as a main communication platform and Sprint meetings, respectively. The results from this study show that the project’s environment is significant alongside the execution of the project management methodology. Further research hopes to focus more on differing STEM environments such as electrical engineering and biological sciences.https://oasis.library.unlv.edu/durep_posters/1222/thumbnail.jp
Characterizing the Mechanical and Visoelastic Properties of Sodium Alginate
No full textA crucial part of tissue engineering lies in understanding and characterizing the mechanical and viscoelastic properties of various types of biomaterials. Understanding these properties allows better biomaterials to be produced with characteristics more similar to those of the human body and with better biocompatability. In this study, sodium alginate was chemically crosslinked with calcium chloride and subsequently tested for it\u27s instantaneous Elastic Modulus, instantaneous Shear Modulus, and equivalent viscosity using indentation testing methods consisting of a stress-relaxation test and nonlinear curve-fitting analysis. Two and three millimeter indentation tests were performed using a low-cost and portable device built in-lab that resulted in five viscoelastic parameters of G_Inf, G_1, G_2, Tau_1, and Tau_2. These values resulted in an average instantaneous Elastic Modulus of 5044 Pascals, an average instantaneous Shear Modulus of 1681 Pascals, and an equivalent viscosity of 4710 Pascal-seconds for an indentation depth of 2 millimeters. Moreover, these values also resulted in an average instantaneous Elastic Modulus of 8553 Pascals, an average instantaneous Shear Modulus of 2851 Pascals, and an equivalent viscosity of 7317 Pascal-seconds for an indentation depth of 3 millimeters. Overall, these findings suggest an increase in viscoelastic and mechanical properties relative to their displacement distance. Understanding the viscoelastic and mechanical behavior of these biomaterials holds clinical significance for designing better implantable prostheses, drug-deliverable medical devices, and wound healing scaffolds.https://oasis.library.unlv.edu/durep_posters/1236/thumbnail.jp