2017 MU theses - Access restricted to MU
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Item Modeling, characterization and evaluation of MU100 high-energy density ceramic nanodielectric for use in pulsed power applications(University of Missouri--Columbia, 2017) Howard, Alexander B.; Curry, Randy D.A high dielectric, nanodielectric, composite material, MU100, was developed by the University of Missouri for use in dielectric loaded antennas. Based on its dielectric strength and losses, MU100 had possible uses in the development for high energy-density capacitors. This work presents the theory behind, methods of preparation and evaluation, modeling and properties of MU100. MU100’s dielectric properties are explored in high energy-density pulsed power applications, compact high voltage capacitors. Small scale tests have shown the average dielectric strength of MU100 to be 225 kV/cm with a peak break down field of 328 kV/cm. When potted, these small-scale capacitors have lifetimes in excess of 800,000 discharges at 80% of their maximum rated field strength. This shows a remarkable development in the performance of high energy density capacitors for use in pulsed power applications.Item The Panama Papers : collaboration and the data/story searching mechanisms in the international investigative journalism project(University of Missouri--Columbia, 2017) Naskidashvili, Nana; Horvit, Beverly, 1967-[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The Panama Papers was a global project that united approximately 400 journalists worldwide. Their investigations are based on 11.5 million leaked files. This research studied how journalists collaborated with each other to produce the Panama Papers project and how the journalists sorted the data to prioritize which documents to study and which stories to work on. Data for the research was collected through the interviews recorded with the journalists and editors who worked and continue to work on the project, based on the biggest data leak in the history of journalism. This study showed there were inner rules everyone had to follow. One of them was a radical sharing of information among the project's participants via a secret communication platform. Participants revealed that journalists were sharing story ideas and giving recommendations to each other. This kind of behavior is not usually observed among reporters whose aim is to be first to publish a story. The close communication between reporters and editors turned out to be another aspect that contributed to the success of the project. And the layers of editors at the Organized Crime and Corruption Reporting Project and the German newspaper Sueddeutsche Zeitung helped to avoid any mistakes in the reporting. Information provided by the participants of the research allows the researcher to draw the following conclusion: The Panama Papers created a new paradigm of a global newsroom based on trust, inner rules and the cooperation of a few hundred journalists. It should be recalled that approximately 400 journalists from all around the globe participated in the Panama Papers. The researcher focused on the work process of the reporters and editors mostly in European countries. It would be interesting to see how these processes developed and worked in Asian and Latin American countries. The researcher assumes that the diversity within the cultures might have affected the work of the media professionals in those parts of the world, and conducting studies about this topic may present information that will help to see the Panama Papers project from a wider angle.Item Biochemical characteristics of different subtypes of human immunodeficiency virus type 1 reverse transcriptase and its interactions with the host factor : apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3G(University of Missouri--Columbia, 2017) Kim, Seongmi; Sarafianos, Stefan G.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Human immunodeficiency virus (HIV) is divided into type 1 (HIV-1) and type 2 (HIV-2). Whereas HIV-2 accounts for 5% of global infections, HIV-1 is responsible for 95% of the global pandemic. HIV-1 is classified into four groups; M, N, O and P. Group M is the most prevalent, including subtypes or clades of A-D, F-H, J, K, over 100 Circulating Recombinant Forms (CRFs), and several Unique Recombinant Forms (URFs). In developed countries (i.e. countries in North America, Western Europe, and Australia), HIV-1B is the most prevalent strain. However, it accounts for only about 12% of worldwide infections. On the other hand, HIV-1C, which is most prevalent in Low- and Middle-Income Countries (LMICs) (e.g. India, Brazil, and many countries in Sub-Saharan Africa), accounts for [about]52% of all HIV infections. Due to its prevalence in developed countries, HIV-1B has been the major target of HIV studies and anti-HIV drug development. However, it has been reported that HIV-1non-B patients have higher rates of treatment failure than HIV-1B patients. To understand the mechanism behind this observation, we applied in vitro biochemical assays, which were performed with four patient-derived reverse transcriptase (RT) proteins isolated from HIV-1B, HIV-1C, CRF01_AE, and CRF02_AG viruses. RT is the HIV enzyme that generates viral DNA from genomic RNA during the early stages of infection, and it is the target for many anti-HIV drugs. RT inhibitors are divided into two types depending on their structure. First, Nucleoside/nucleotide Reverse Transcriptase Inhibitors (NRTIs), which bind the active site of the RT and act as chain terminators. In addition, a new type of NRTI, called 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA), works as a translocation inhibitor. Second, Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) inhibit RT by binding to an allosteric site. Nevirapine (NVP) belongs to the first generation of NNRTIs, however HIV-1 develops resistance mutations frequently during NVP treatment. Rilpivirine (RPV) has been developed to target NVP-resistant viruses but it is not frequently used in LMICs. In this study, we determined the biochemical characteristics of HIV-1 RTs from various subtypes and determined kinetic constants of inhibition by EFdA, NVP, and RPV. The results show that all of the tested HIV-1 RTs incorporate EFdA with better efficiency than their natural cognate substrate, dATP, which suggests that EFdA would be effective against all of the tested HIV-1 subtypes. Furthermore, generally NVP binds RTs with a lower affinity than RPV, implying that NVP would be a less effective inhibitor than RPV. However, in the case of CRF02_AG RT, NVP binds with similar affinity to RPV, suggesting CRF02_AG patients may respond better to NVP than patients infected with other subtypes. HIV-1C has less binding affinity to RPV than other subtypes, which is consistent with clinical reports showing that HIV-1C patients have a higher rate of treatment failure with RPV. Finally, we have studied the effect of a host factor, apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3G (APOBEC3G), on HIV-1 RT. APOBEC3G (A3G) has been reported to inhibit several retroviral infections. To date, there are two established mechanisms of this inhibition, which are hyper-mutagenesis and roadblock. In this study, we investigated a third mechanism, the direct inhibition of HIV-1 RT, using in vitro RT assays. Our results showed that A3G does inhibit the activity of HIV-1 RT by affecting the catalytic rate of dNTP incorporation (kcat), supporting the direct inhibition mechanism. Interestingly, A3G had similar inhibitory activity against a related viral RT (from Moloney Murine Leukemia Virus), but no activity against DNA polymerase I.Item Stimulus specific adaptation in the hearing system of Neoconocephalus katydids (insecta: Orthoptera)(University of Missouri--Columbia, 2017) Johnson, Luesoni D.; Schul, Johannes[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Stimulus Specific Adaptation (SSA) is a fundamental response that identifies novel signals within a repetitive background noise. It is well characterized in the vertebrate auditory system, but has been studied only in a relatively small number of studies involving invertebrates. Neoconocephalus katydids have one auditory interneuron (TN-1) that can detect rare signals (e.g. bat cries) within a repetitive background (e.g. male calls). It is assumed that TN-1 produces SSA-like responses whenever the bat cries were detected, however no formal test (e.g. oddball design) for SSA was conducted. In this present study using an oddball design, TN-1 showed SSA with varying response strengths based on three variables. The variables included a low deviant probability (<50%), a large frequency separation (>0 octaves) and a fast pulse rate ([greater than or equal to] 25 Hz). The responses were also replicated across two Neoconocephalus species. As a result, this study fulfilled my aim to establish the katydid neuron as a good model to study SSA due to the similarities found in other katydids and mainly to the responses observed in the vertebrate neuron. Additionally, since many experimental approaches are performed in TN-1 from the cellular, molecular, and genetic level, this makes TN-1 an ideal candidate to further investigate the complexities of SSA at many levels.Item Using Facebook for queering Islam(University of Missouri--Columbia, 2017) Iftekhar, Anadil; Mislán, Cristina[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This study addresses the discourses surrounding queer Muslims by Muslims for Progressive Values (MPV). MPV, a non-profit rights organization based out of the US, advocates for LGBTQ rights within Islam and has used theological standing to fight the prejudice that queer Muslims face. They increasingly rely on their social media to address both Muslim and non-Muslim communities worldwide. This research analyzed MPV's Facebook to examine their discourse on LGBTQ rights in Muslim communities across the globe. Facebook is by far the most popular online platform; with more than 2 billion users, it allows the message of the user to reach a global audience. As queer Muslim comprise two marginalized identities-- LGBTQ people are marginalized everywhere whereas Muslims are discriminated in the West--the LGBTQ Muslims are an intersectional identity. Intersectionality becomes the defacto analytical framework when any two identities are converged in relation to social power. Therefore, this study uses the theoretical framework of intersectionality to analyze MPV's arguments. The data for the study came from MPV's page and the public profile of their president, Ani Zonneveld. Using discourse analysis, this study found that MPV promotes a view of LGBTQ Muslims that differs substantially from Western perspectives and many mainstream Muslim groups. What is particularly striking about their argument is that while both Western and traditional Islamic discourse identify LGBTQ rights as incompatible with Islam, MPV claims that Islam is inherently inclusive of queer rights. Therefore, MPV actually presents an alternative paradigm that resists Western notions about the inherent intersectional marginalization of Muslim queer communities, even as it challenges conservative Muslim stances on queer rights. Using intersectionality as an analytical framework reveals how this discourse reflects the need to integrate Islam with queer thought in a way that acknowledges their co-constitution rather than mutual exclusion.