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489 Days

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489 Days is an animated documentary about the harrowing experiences of Egyptian-American Mohamed Soltan, who survived 16 months of hunger strike in an Egyptian prison. Caught up in the political turmoil which followed the Arab Spring uprisings, Soltan was unjustly incarcerated between August 2013 and May 2015, when the United States government intervened to release him weeks after an Egyptian court sentenced him to life in prison. The film is also the larger story of an estimated 60,000 political detainees currently held in Egypt without due process, and in violation of local and international human rights conventions.
Date: August 2019
Creator: Elmalky, Rania
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Accuracy of Three Assessments of Sleep Timing, Duration and Efficiency Compared to a Single-Channel EEG Device (open access)

Accuracy of Three Assessments of Sleep Timing, Duration and Efficiency Compared to a Single-Channel EEG Device

Poor sleep measured across many dimensions has been linked to adverse physical and mental health outcomes including cardiovascular disease, diabetes, cancer, increased mortality, depression, and anxiety. Current research typically relies upon brief, subjective, inadequately validated methods to assess limited dimensions of sleep, resulting in inaccurate measurements and possibly faulty conclusions. Specifically, research validating objective (e.g., actigraphy) and subjective (e.g., sleep diaries, retrospective surveys) measurement methods against the gold standard of polysomnography (PSG, an overnight sleep study) is primarily limited by a) a lack of reliability based on too short (e.g., 24 or 48 hours) of an assessment period to capture night-to-night variability, b) a lack of ecological validity (e.g., full PSG in a laboratory setting), and c) a lack of generalizability due to limited or special populations (e.g., individuals with insomnia). Barriers such as prohibitive cost, extensive setup time, and personnel training requirements diminish the ability of researchers to conduct measurement comparison studies using gold standard measures like traditional PSG. These barriers can be circumvented with the use of low-cost, minimally invasive single-channel EEG devices (e.g., Zmachine), but to date few studies have employed these devices. The current study evaluated the accuracy of retrospective surveys, sleep diaries, and actigraphy compared …
Date: August 2019
Creator: Dietch, Jessica R.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Addressing Technical and Musical Demands of Contemporary Music for Horn through Newly-Composed Etudes (open access)

Addressing Technical and Musical Demands of Contemporary Music for Horn through Newly-Composed Etudes

Contemporary music for horn often requires techniques and musical or notational considerations that are unconventional with respect to the standard pedagogy of the instrument. As such, these considerations often represent a level of challenge to which the average-intermediate to advanced-hornist is unprepared to approach or altogether unfamiliar. The most prominent of these demands arising in the last few decades of the twentieth century through today include microtonality (such as extended just intonation and quarter tones), extended techniques in combination or juxtaposition (such as multiphonics and right hand technique), rhythmic complexity (including metric modulation, non-dyadic meters, additive rhythms, and nested tuplets), and unconventional notations (graphic, spatial, and other temporal notations). This document first surveys the challenges of the repertoire in question, which includes works by György Ligeti, Thea Musgrave, Milton Babbitt, Brian Ferneyhough, Iannis Xenakis, Heinz Holliger, and Douglas Hill, among others. After considering the merits and limitations of existing pedagogical materials that work towards these ends, the document then underlines a strategic pedagogical goal for understanding and approaching unconventional contemporary repertoire through newly-composed etudes. This document is written in conjunction with and justification for the author's 24 Unconventional Etudes for Horn, and includes examples therefrom.
Date: August 2019
Creator: Hessel, Eric
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adult Attachment, Cultural Orientation and Sacrifice in Couples: A Comparison between American and Chinese Samples (open access)

Adult Attachment, Cultural Orientation and Sacrifice in Couples: A Comparison between American and Chinese Samples

The present study examined the effects of adult attachment and cultural orientation on sacrifice behaviors and the corresponding emotional reactions, using a cross-cultural sample in the U.S. and China. Strain-tests protocol was utilized in this study, in which an individual (i.e., the asker) was asked to share with their romantic partner a personal goal that required a major sacrifice from their partner (i.e., the responder), and then entered a discussion to process their plan of carrying out this goal. The final sample included 115 couples from the U.S. and 99 couples from China. Results indicated that responder's attachment avoidance was negatively associated with sacrifice offered to their partners and they reported more positive emotions as a result. The interaction between attachment anxiety and nationality was significant. Specifically, in the U.S. sample, individuals with high attachment anxiety were more likely to offer sacrifice for their partners, but this effect was reversed in the Chinese sample. In addition, interdependent self-construal (ISC) was a significant moderator for the relation between attachment anxiety and sacrifice behavior. Individuals who endorsed higher ISC and higher anxious attachment were less likely to make sacrifice for their partner. Furthermore, when individual offered more sacrifice, they reported more positive …
Date: August 2019
Creator: Zhu, Wenzhen
Object Type: Thesis or Dissertation
System: The UNT Digital Library
American and Canadian Parents' Perceptions of Virtual Education: A Case Study of K-12 Students Living in Saudi Arabia (open access)

American and Canadian Parents' Perceptions of Virtual Education: A Case Study of K-12 Students Living in Saudi Arabia

This exploratory study investigates how American and Canadian parents living in Saudi Arabia perceive enrolling their children in an online virtual school. This research is relevant to North Americans living and working overseas and how these parents access educational opportunities for their children. North American parents living in Saudi Arabia with children have limited local educational options. If parents decided not to enroll their child in traditional private local international education, alternatives include boarding school, homeschool, or online school. Of the surveyed participants, 68% of parents had enrolled their children in online education or expressed interest in enrolling their children in online education but many lack information and knowledge about online education. A qualitative study analyzed participants in semi-structured interviews. Besides academic satisfaction, the most common reasons for alternative education are the lack of available competitive sports and the arts, including theatre and music. Four themes emerged from the data. Parent satisfaction about their children's education shifts from positive to negative around 8th or 9th grade. Parents are, in general, unwilling to take a risk on an unproven online school. Local private international schools are the focal point of extra-curricular activities and social events, but families lack connections and a …
Date: August 2019
Creator: Lackey, Karen Michelle
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Analyses of Proposed Constitutional Amendments: November 5, 2019, Election (open access)

Analyses of Proposed Constitutional Amendments: November 5, 2019, Election

The ten joint resolutions proposing amendments to the Texas state constitution offered for approval by Texas voters in the November 5, 2019, election ballot. Includes the ballot language, an analysis of each proposed amendment, and the text of the joint resolution proposing the amendment. Each analysis includes background information and a summary of comments made during the legislative process about the proposed constitutional amendments by supporters and opponents.
Date: August 2019
Creator: Texas Legislative Council
Object Type: Legislative Document
System: The Portal to Texas History
An Analysis and Performance Guide of Selected Works for Saxophone by Cuban Composers Jorge Luis Sosa and Andrés Alén-Rodriguez (open access)

An Analysis and Performance Guide of Selected Works for Saxophone by Cuban Composers Jorge Luis Sosa and Andrés Alén-Rodriguez

A large portion of the standard repertoire for saxophone and piano has already been recorded and performed many times and has received significant scholarly study. For a performer, remaining relevant requires learning and performing new compositions. Jorge Sosa and Andrés Alén are both accomplished composers, yet outside of the Latin-American community they remain virtually unknown to most saxophonists. This project serves as an introduction to both composers. Combined, Sosa and Alén have nine compositions for saxophone. Their works include saxophone quartets, saxophone and piano, and saxophone quartet with choir. This study focuses on three compositions: La Zacapaneca by Sosa, Tema con Variaciones and Sonata para Clarinete ó Saxofón Soprano y Piano, both by Alén. Compositional background information is given about each composition to include date of composition, premiers, important recordings, length of performance and Cuban ethnic and traditional elements used as the basis for rhythmic and thematic ideas. The Cuban and Afro-Cuban influences are explained in further detail pertaining to how they were used in the construction of the works and in their being performed stylistically correctly. Dynamics, articulations, and performance considerations are studied at length.
Date: August 2019
Creator: Friel, Stephan
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Application-Focused Investigation of Monovalent Metal Complexes for Nanoparticle Synthesis

Access: Use of this item is restricted to the UNT Community
Over the last 20 years, there has occurred an increase in the number, scope, and impact of nanomaterials projects. By leveraging the Surface Plasmon Resonance of metallic nanoparticles for labelling, sensing, and treatment, researchers have demonstrated the versatile utility of these nanomaterials in medicine. The literature provides evidence of use of simple, well-known chemistry for nanomaterials synthesis when the focus is new applications of nanomaterials. A case in point, is the synthesis of metallic nanoparticles, whereby HAuCl4, CuCl2, Cu(acac)2, and AgNO3 are typically employed as nanoparticle precursors. Unfortunately, the use of these precursors limits the number of applications available to these materials - particularly for AuNPs in medicine, where the byproducts of nanoparticle synthesis (most often surface-adsorbed reductants, toxic stabilizers, and growth directors) cause nanoparticles to fail clinical trials. Despite the several thousand publications detailing the advancements in nanoparticle therapeutics, as of 2017, there were only 50 FDA-approved nanoparticle formulations. Less than 10 were based on metallic nanoparticles. This is a problem because many of these nanoparticle therapeutics demonstrate potent cell killing ability and labeling of cells. A solution to this problem may be the use of weakly coordinated, monovalent metal complexes, which require only one electron to reduce them …
Date: August 2019
Creator: Kamras, Brian Leon
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Application of Adaptive Techniques in Regression Testing for Modern Software Development (open access)

Application of Adaptive Techniques in Regression Testing for Modern Software Development

In this dissertation we investigate the applicability of different adaptive techniques to improve the effectiveness and efficiency of the regression testing. Initially, we introduce the concept of regression testing. We then perform a literature review of current practices and state-of-the-art regression testing techniques. Finally, we advance the regression testing techniques by performing four empirical studies in which we use different types of information (e.g. user session, source code, code commit, etc.) to investigate the effectiveness of each software metric on fault detection capability for different software environments. In our first empirical study, we show the effectiveness of applying user session information for test case prioritization. In our next study, we apply learning from the previous study, and implement a collaborative filtering recommender system for test case prioritization, which uses user sessions and change history information as input parameter, and return the risk score associated with each component. Results of this study show that our recommender system improves the effectiveness of test prioritization; the performance of our approach was particularly noteworthy when we were under time constraints. We then investigate the merits of multi-objective testing over single objective techniques with a graph-based testing framework. Results of this study indicate that the …
Date: August 2019
Creator: Azizi, Maral
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Applications of a Model-Theoretic Approach to Borel Equivalence Relations (open access)

Applications of a Model-Theoretic Approach to Borel Equivalence Relations

The study of Borel equivalence relations on Polish spaces has become a major area of focus within descriptive set theory. Primarily, work in this area has been carried out using the standard methods of descriptive set theory. In this work, however, we develop a model-theoretic framework suitable for the study of Borel equivalence relations, introducing a class of objects we call Borel structurings. We then use these structurings to examine conditions under which marker sets for Borel equivalence relations can be concluded to exist or not exist, as well as investigating to what extent the Compactness Theorem from first-order logic continues to hold for Borel structurings.
Date: August 2019
Creator: Craft, Colin N.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Are Things Falling Apart Again? A Dialectical Analysis of Language Education Policy in Nigeria (open access)

Are Things Falling Apart Again? A Dialectical Analysis of Language Education Policy in Nigeria

Today's globalized world presents challenges for formulating language education policies in multilingual countries, and postcolonial Nigeria presents a dramatic illustration because of ongoing colonial influences as well as neocolonial factors. This study focused on dialectical relations over time among languages in Nigeria's National Policy on Education (NPE), published in 1977, 1981, 1998, 2004, 2013, and 2014. The title of the study harks to Chinua Achebe's novel, Things Fall Apart, which described the disruption of tribal cultures and languages when Europeans brought their culture and language to Nigeria. Attention in this dissertation, which examined Nigerian education policy over four decades, was also on things falling apart, being resolved in some way, and then falling apart again. Four major dialectical tensions can be seen as the NPE went through revisions in language of instruction and language of study. First, relations between English and indigenous languages showed the increasing importance of English despite ostensible attempts to promote indigeneity through language. Particularly important was the influence of globalization, which emphasized neoliberal values and initiatives associated with global English. Second, relations among the various indigenous languages showed three languages—Hausa, Igbo, and Yoruba—to be privileged over 522 other languages that were marginalized but retained as "mother …
Date: August 2019
Creator: Olaniyi, Adepeju Folasade
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Are You a Good Witch or a Bad Witch? The Importance of Object Relations in Modern Assessment (open access)

Are You a Good Witch or a Bad Witch? The Importance of Object Relations in Modern Assessment

The Social Cognition and Object Relations Scale—Global (SCORS-G) is a relatively new scoring system for the Thematic Apperception Test (TAT) that provides information about an individual's functioning in a variety of domains, including intrapsychic and interpersonal. Participants in this archival study had been administered a variety of measures as part of a routine clinical assessment, including the TAT, Rorschach, Minnesota Multiphasic Personality Inventory-2, and the Wechsler Adult Intelligence Scale. Selected TAT stories were rescored using current SCORS-G scoring criteria. This dissertation evaluated the factor structure of the SCORS-G in an outpatient sample with a principal component analysis (PCA), finding support for a two-component solution. The SCORS-G was then compared to well-established measures of personality functioning, social cognition, and object relations using correlational analyses, with mixed results. Lastly, support was found for using the SCORS-G as a tool for discriminating individuals with a history of violent or problematic relationships from those without such a history. Implications for card selection based on card pull and the impact of bland protocols were explored.
Date: August 2019
Creator: Weber, Katherine Mary
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Artificial Intelligence & Wireless Spectrum: Opportunities and Challenges (open access)

Artificial Intelligence & Wireless Spectrum: Opportunities and Challenges

This report is a summary of the Artificial Intelligence and Wireless Spectrum: Opportunities and Challenges conference. The purpose of the workshop was to identify areas where AI techniques, including ML, can help increase efficiency of wireless spectrum use and to discuss ongoing spectrum management research that utilizes AI techniques.
Date: August 2019
Creator: Lee, Joyce; Nandagopal, Thyga & DiFrancisco, Mike
Object Type: Report
System: The UNT Digital Library
Artistic Learning in an MFA Community (open access)

Artistic Learning in an MFA Community

The purpose of this phenomenographical case study is to explore the ways in which a group of MFA students conceive of their learning as they are enmeshed within an MFA community. The research follows along two guiding research questions: 1) What does artistic learning involve for graduate students in an MFA community? 2) How is one's artistic practice shaped by one's active participation in an MFA community? The findings of this study have been presented as lines of artistic learning and help to show the various conceptions that MFA students have of their learning as artists while in an MFA program of study. Ultimately, it is in better understanding one's lines of artistic learning that MFA students can be better supported in their journeying to become professional, practicing artists.
Date: August 2019
Creator: Jilka, Milan
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Asian and Asian Indian American Immigrant Students: Factors Influencing Their Academic Performance

Access: Use of this item is restricted to the UNT Community
Asian American students have done well in school; they have had higher academic achievements, higher academic scores, lower dropout rates and higher college entrance rates as compared to other minorities and generally other students in the United States (U.S.). A possible explanation to the higher academic performance and achievement of the Asian American students is that they are more likely to have experienced an environment that is conducive to learning at home; their parents were involved and held higher expectations. Immigrant minorities have been found to do well in schools in many parts of the world. Similarly, here in the U.S. there has been increasing evidence that students of Asian ancestry, both immigrants and U.S. born, complete more years of education than most of the other ethnicities. Current research and data on the academic performance of Asian immigrants includes most Asian countries. This study reviewed the current literature regarding the factors that influence the academic performance of "Asian Indian Americans" who attended high schools in the U. S. This correlational study examined the relationship between various factors, such as parental participation, parental expectations and involvement, discipline, cultural beliefs, personal identity and values, language spoken at home, and the academic performance …
Date: August 2019
Creator: Mathew, Subhas
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Audiovisual Concatenative Synthesis and "Replica" (open access)

Audiovisual Concatenative Synthesis and "Replica"

Audiovisual concatenative synthesis is an analysis-driven granular technique using a corpus of multimedia data to sequence audio and video streams on a microtemporal level. This text outlines my development of this technique as a tool for multimedia composition, using my work, Replica, as a case study. The paper illustrates how the concepts of granular structure, gesture capture, and replication are integral not only to the software but to the architecture of the composition. In doing so, machine learning approaches to music and visual art are reviewed and related to my personal compositional practice. Additionally, I attempt to show how audiovisual concatenative synthesis provides a composer with strategies for shaping one's sense of time through disorienting audiovisual cues and tightly organized counterpoint between sound and image, stage and screen, and the real and virtual.
Date: August 2019
Creator: Thomas, Zach (Zachary R.)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 99, No. 150, Ed. 1 Thursday, August 1, 2019 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 99, No. 150, Ed. 1 Thursday, August 1, 2019

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: August 1, 2019
Creator: Bloom, David
Object Type: Newspaper
System: The Portal to Texas History
A Behavioral Analysis of the Stroop Effect (open access)

A Behavioral Analysis of the Stroop Effect

Participants demonstrate the Stroop effect when, in naming the color in which a word appears, reaction times are longer when the color and word are incongruent (e.g., "yellow" printed in blue) compared to when they are congruent (e.g., "yellow" printed in yellow). The literature commonly refers to the difference in reaction times as a measure of the interference of word stimuli upon color stimuli, and is taken as support for the theory of automaticity. This study asks whether the Stroop effect can be analyzed as interactions within and across stimulus classes. Adult participants learned three 3-member classes (color, word, and pattern) in a serialized order of training. In the testing phase, participants were presented with compound stimuli formed from combinations of members within and across classes (e.g., word and color), and reaction times were recorded in similar fashion to the Stroop task. Results show that averaged participants' reaction times are faster to compound stimuli comprised of members within the same class, compared to compound stimuli formed with members from different classes. These group-level data are consistent with the Stroop literature in that congruent compounds produce faster reaction times relative to incongruent compounds. However, individual participant data do not consistently reflect …
Date: August 2019
Creator: Luc, Oanh
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Beyond Nothingness: A Broader Nihilism in Cinema Paradiso by Stephen Goss

Access: Use of this item is restricted to the UNT Community
Stephen Goss composed Cinema Paradiso, a six-movement suite for solo guitar, as an homage to films and film directors. Goss cites nihilism as a theme in Dogville, the film that inspires the fourth movement, "Mandalay," but I assert that all the films and many musical devices throughout the piece can be read through the lens of nihilism. The first movement, "Paris, Texas," depicts the stark landscape of the opening scene of the 1984 Wim Wenders film of the same name. "Modern Times" chronicles Charlie Chaplin's slapstick-laden descent from the factory to the insane asylum in the opening sequence of his 1936 Modern Times. "Noir" is a tribute to the procedures of film noir: violent storylines that depict the harshness of life, dim lighting, and anti-hero characters, all accompanied by jazz. Lars von Trier's Dogville provides the movement "Mandalay" with its nihilistic meaning, but Goss writes that he invokes the musical style of Kurt Weill's opera The Rise and Fall of the City of Mahagonny. Just as the book people of François Truffaut's Fahrenheit 451 had to pass on books orally, Goss has burned the score for his "451," forcing guitarists to learn it by watching a video and listening to …
Date: August 2019
Creator: Kyzer, Dan
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Bipolar Spectrum Traits in Day-to-Day Life: Ecological Momentary Assessment of Reward Sensitivity, Circadian Timing, and Experience of Reward in the Environment

Access: Use of this item is restricted to the UNT Community
The current study examined 236 undergraduate students in a week long twice-per-day ecological momentary assessment exploring the influence of baseline reward sensitivity and interactions between circadian variables (i.e., total sleep time, sleep quality) and daily measures of reward. Though primary study findings did not support reward sensitivity related moderation of sleep-reward pathways, a number of notable findings emerged. We found evidence of specific domains of reward sensitivity (anticipatory reward and reward responsiveness) which are uniquely related to daily experiences of reward. In addition, bidirectional circadian-reward pathways were found between sleep quality and daily rewards which suggests pathways towards reward-related engagement. Evidence also supported interactions between sleep quality and total sleep time on experience of daily reward, further highlighting the complexity of sleep-reward pathways and their relevance to mood symptoms.
Date: August 2019
Creator: Smith, Patrick M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Bright Mosaic (open access)

Bright Mosaic

Bright Mosaic is a 30-minute documentary about a comprehensive autism center for children with an organic and unconventional approach. The Bright Mosaic Autism Therapy Center's exceptional curriculum consists of a mix of Montessori practices, natural sciences, applied behavior analysis, occupational therapy, speech therapy, physical therapy, play therapy, music therapy, sensory integration, daily life skills and art. Bright Mosaic mixes observational and participatory styles in an effort to portray an exceptionally skilled and passionate team who fights a tough daily battle to prepare their children for the life ahead of them.
Date: August 2019
Creator: Mares, Vicente
Object Type: Thesis or Dissertation
System: The UNT Digital Library
BSM Message and Video Streaming Quality Comparative Analysis Using Wave Short Message Protocol (WSMP) (open access)

BSM Message and Video Streaming Quality Comparative Analysis Using Wave Short Message Protocol (WSMP)

Vehicular ad-hoc networks (VANETs) are used for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. The IEEE 802.11p/WAVE (Wireless Access in Vehicular Environment) and with WAVE Short Messaging Protocol (WSMP) has been proposed as the standard protocol for designing applications for VANETs. This communication protocol must be thoroughly tested before reliable and efficient applications can be built using its protocols. In this paper, we perform on-road experiments in a variety of scenarios to evaluate the performance of the standard. We use commercial VANET devices with 802.11p/WAVE compliant chipsets for both BSM (basic safety messages) as well as video streaming applications using WSMP as a communication protocol. We show that while the standard performs well for BSM application in lightly loaded conditions, the performance becomes inferior when traffic and other performance metric increases. Furthermore, we also show that the standard is not suitable for video streaming due to the bursty nature of traffic and the bandwidth throttling, which is a major shortcoming for V2X applications.
Date: August 2019
Creator: Win, Htoo Aung
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Carbon Nanotubes and Molybdenum Disulfide Protected Electrodes for High Performance Lithium-Sulfur Battery Applications

Access: Use of this item is restricted to the UNT Community
Lithium-sulfur (Li-S) batteries are faced with practical drawbacks of poor cycle life and low charge efficiency which hinder their advancements. Those drawbacks are primarily caused by the intrinsic issues of the cathodes (sulfur) and the anodes (Li metal). In attempt to resolve the issues found on the cathodes, this work discusses the method to prepare a binder-free three-dimensional carbon nanotubes-sulfur (3D CNTs-S) composite cathode by a facile and a scalable approach. Here, the 3D structure of CNTs serves as a conducting network to accommodate high loading amounts of active sulfur material. The efficient electron pathway and the short Li ions (Li+) diffusion length provided by the 3D CNTs offset the insulating properties of sulfur. As a result, high areal and specific capacities of 8.8 mAh cm−2 and 1068 mAh g−1, respectively, with the sulfur loading of 8.33 mg cm−2 are demonstrated; furthermore, the cells operated at a current density of 1.4 mA cm−2 (0.1 C) for up to 150 cycles. To address the issues existing on the anode part of Li-S batteries, this work also covers the novel approach to protect a Li metal anode with a thin layer of two-dimensional molybdenum disulfide (MoS2). With the protective layer of MoS2 …
Date: August 2019
Creator: Cha, Eunho
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Ceramide Biosynthesis and NEET Proteins Impact Development, Function, and Maintenance of the Caenorhabditis elegans Germline

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I used the C. elegans genetic model to examine the role of ceramide biosynthesis (sphingolipid pathway) and iron regulation and found that each process impacts germline development and function. Using a sphingolipid specific antibody mAb15B4, I found that sphingolipids are associated with germ granules (P granules) within C. elegans and zebrafish; thus, suggesting conservation of macromolecules associated with germ granules. Phenotype analysis of ceramide biosynthesis mutants in C. elegans revealed that this pathway is essential for normal germline function in the aging adult hermaphrodite; specifically, precocious germline senescence was observed. Furthermore, I found that disruption of ceramide biosynthesis, via the hyl-2 deletion mutation, negatively impacts mAb15B4 localization at the P granules. Through genetic suppression analysis, I determined that insulin signaling and lipid biosynthesis can modulate the mAb15B4 localization to P granules. Additional, phenotype analysis showed that ceramide biosynthesis dysfunction decreased fecundity, and led to germline structure defects and uterine tumors. Through suppression analysis, I determined that modulation of the insulin signaling pathway suppressed the precocious germline senescence due to ceramide biosynthesis dysfunction. Since the presence of uterine tumors is associated with reproductive senescence I concluded that ceramide biosynthesis has a role in germline maintenance in the aging of the germline …
Date: August 2019
Creator: King, Skylar Dawn
Object Type: Thesis or Dissertation
System: The UNT Digital Library