UNT Theses and Dissertations - 857 Matching Results

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The Role of Gabergic Inhibition in Modulating Receptive Field Size of Cuneate Neurons

Description: A blockade of GABAergic inhibition increases the receptive field(RF) size of most somatosensory cortex (SI) and some ventrobasal thalamus (VB) neurons. The results suggest RF size of cuneate neurons may be modulated through GABAa and GABAb receptors, independent of firing frequency.
Date: August 1997
Creator: Tennison, Cullen F.
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Head Trauma Release of Histamine from Dural Mast Cells Alters Blood-Brain Barrier: Attenuation with Zolantidine

Description: This study employed a new model of mild-to-moderate head trauma to specifically identify the role of dural mast cell (MC) histamine in trauma-induced increased permeability in the blood-brain barrier (BBB). A single line was scored partially through the left dorsal parietal skull. Immediately following the trauma, degranulation was seen in 39% of the MCs on the left and in 2% on the right. After a 20 min survival period, left duras showed 55% with MC degranulation (fewer with complete degranula… more
Date: December 2000
Creator: Laufer, Susan R.
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Characterization of Arthrobacter Globiformis Aspartate Transcarbamylase Concentrations of Substrates

Description: This thesis consists of one major section with two subsections. The first subsection investigates the activity of Arthrobacter globiformis aspartate transcarbamylase's specific activity with increasing concentrations of the enzyme's substrate. Dihydroorotase (DHOase) activity was also measured with increasing concentrations of the substrate dihydroorotate. The second subsection collected data in order to classify the enzyme, resulting in a classification into the category of class A ATCases … more
Date: December 2012
Creator: Wright, Jackie
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Bioconcentration and Morphological Effects of Triclosan on Three Species of Wetland Plants

Description: Triclosan (TCS) is an antimicrobial compound found in several types of common household products. After being washed down the drain, TCS will then end up in the local watershed. Although numerous studies have been conducted to evaluate the fate and effects of TCS in aquatic environments, there have been no studies evaluating the role arbuscular mycorrhizal fungi (AM) play in a plants response to TCS exposure. Three species of wetland plants native North Texas were inoculated with AM spores and … more
Date: May 2013
Creator: Smith, Caleb M.
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Exploring the Evolutionary History of North American Prairie Grouse (Genus: Tympanuchus) Using Multi-locus Coalescent Analyses

Description: Conservation biologists are increasingly using phylogenetics as a tool to understand evolutionary relationships and taxonomic classification. The taxonomy of North American prairie grouse (sharp-tailed grouse, T. phasianellus; lesser prairie-chicken, T. pallidicinctus; greater prairie-chicken, T. cupido; including multiple subspecies) has been designated based on physical characteristics, geography, and behavior. However, previous studies have been inconclusive in determining the evolutionary h… more
Date: May 2013
Creator: Galla, Stephanie J.
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Aging Is a Determinant in Anoxia Stress Tolerance in Caenorhabditis Elegans

Description: Oxygen availability is critical for survival for most organisms. The nematode, C. elegans, has been useful for studying genetic regulation of anoxia tolerance due to the oxygen deprivation response mechanisms shared with other metazoans. Studies examining long-term anoxia (72h, LTA) tolerance have only been conducted at adult day 1. To investigate the effect of aging on anoxia tolerance wild-type and mutant strains were exposed to LTA between adult day 1 and day 9. Wild-type isolates and daf-16… more
Date: May 2013
Creator: Goy, Jo M.
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Evaluating the Habitat Requirements of the Golden Orb Mussel (Quadrula Aurea) for Conservation Purposes

Description: Many freshwater mussels are imperiled, due to a number of interrelated factors such as habitat alteration, degradation of water quality, and impoundments. The Golden Orb mussel (Quadrula aurea, I. Lea, 1859) is endemic to the state of Texas and is currently a candidate for the endangered species list, as the number of known populations has been declining in recent years. Little is currently known about Q. aurea aside from basic distribution data. This study is focused on evaluating a combinatio… more
Date: May 2013
Creator: Hammontree, Sarah
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Primary Cilia in the Oligodendrocyte Lineage

Description: oligodendrocytes migrate from the corpus callosum into the overlying cortex. The incidence of cilia did not change markedly across age groups, and did not vary consistently with the number of processes per cell, which was used as an indication of the maturation stage of OPCs and young OLs. The mean percent of Olig1 immunopositive (Olig1+) cells having cilia across ages was 33.1% + 16.5%, with all ages combined. In O4+ cells of these mice, 56.7 + 3.6% had primary cilia. If it is the case that ad… more
Date: May 2013
Creator: Hao, Yung-Chia
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Examination of the Relationship Between Glucuronic Acid and Vascular Damage in Rats

Description: The goal of this experiment was to examine the role of glucuronic acid in the development of vascular damage in the kidneys and retinas of diabetic individuals. Glucuronic acid was provided to rats in their water at various concentrations in order to increase plasma levels of the compound. Kidneys and retinas were excised and compared to control specimens using microscopy to determine the effect of elevated blood glucuronic acid levels on the occurrence of microaneurysms in renal capillary netw… more
Date: May 2013
Creator: Moore, Ryan
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Genetic Interest Assessment

Description: Genetics is becoming increasingly integrated into peoples' lives. Different measures have been taken to try and better genetics education. This thesis examined undergraduate students at the University of North Texas not majoring in the life sciences interest in genetic concepts through the means of a Likert style survey. ANOVA analysis showed there was variation amongst the interest level in different genetic concepts. In addition age and lecture were also analyzed as contributing factors t… more
Date: May 2013
Creator: Doughney, Erin
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The Developmental Physiology of the Zebrafish: Influence of Environment and Cardiovascular Attributes

Description: Temperature effects on the development of the zebrafish embryos and larvae and adults were examined. It was found that the earlier in development a temperature change was performed on an embryo, the more significant the change in survival and/or subsequent development. Thus, viable temperature ranges for zebrafish widened significantly as development proceeded. Adults reared and bred at 25oC produced embryos that were significantly more successful at the lower range of rearing temperatures comp… more
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Date: August 2001
Creator: Bagatto, Brian
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Comparative Morphology of Sensilla Styloconica on the Proboscis of North American Nymphalidae and Other Selected Taxa: Systematic and Ecological Considerations.

Description: Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species withi… more
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Date: December 2001
Creator: Petr, Daniel
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A Novel Phytoestrogen that Acts as an Agonist for Human Estrogen Receptors.

Description: Estrogen is the natural agonist of the estrogen receptor (ER). However, certain plant-derived compounds or phytoestrogens have been identified that mimic estrogens and act as agonists and/or antagonists of ERs, depending on subtype and target tissue. Understanding how phytoestrogens interact with ERs, and therefore effect the estrogenic response, may prove beneficial in hormone replacement therapy and in the prevention and treatment of hormone-related diseases. Using Thin Layer Chromatography, … more
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Date: December 2001
Creator: Pearce, Virginia
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Investigations of neuronal network responses to electrical stimulation in murine spinal cultures.

Description: Spontaneous activity in neuronal networks in vitro is common and has been well documented. However, alteration of spontaneous activity in such networks via conditioning electrical stimulation has received much less experimental attention. Two different patterns of electrical stimulation were used to enhance or depress the level of spontaneous activity in spinal cord cultures. High-frequency stimulation (HFS), a method routinely shown to increase the efficacy of synaptic transmission, was employ… more
Date: December 2001
Creator: Sparks, Christopher A.
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A laboratory course in experimental genetics for the biology major.

Description: This manual has been designed for a class of twenty- four students concurrently enrolled in the lecture course. The laboratory aids in the learning process and fosters an interest in the science of genetics. This manual and the experiments contained within are both informative and fun. The manual correlates with and expands upon the genetics course. Each investigation, with the exception of the Drosophila melanogaster project, can be completed in a 3-4 hour timeframe. This manual provides a “ha… more
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Date: December 2001
Creator: Lux, Melissa McNeil
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Life History and Secondary Production of Caenis latipennis Banks (Ephemeroptera: Caenidae) in Honey Creek, Oklahoma

Description: A study of the life history and secondary production of Caenis latipennis, a caenid mayfly, was conducted on Honey Creek, OK. from August 1999 through September 2000. The first instar nymph was described. Nymphs were separated into five development classes. Laboratory egg and nymph development rates, emergence, fecundity, voltinism, and secondary production were analyzed. C. latipennis eggs and nymphs take 132 and 1709 degree days to develop. C. latipennis had an extended emergence with fiv… more
Date: August 2001
Creator: Taylor, Jason M.
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Unique applications of cultured neuronal networks in pharmacology, toxicology, and basic neuroscience

Description: This dissertation research explored the capabilities of neuronal networks grown on substrate integrated microelectrode arrays in vitro with emphasis on utilizing such preparations in three specific application domains: pharmacology and drug development, biosensors and neurotoxicology, and the study of burst and synaptic mechanisms. Chapter 1 details the testing of seven novel AChE inhibitors, demonstrating that neuronal networks rapidly detect small molecular differences in closely related comp… more
Date: May 2001
Creator: Keefer, Edward W.
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Autoradiographic Localization of Carbachol-Induced Second Messenger Response in the Rat Spinal Cord Following Inflammation.

Description: This study examined central mechanisms of persistent pain using an autoradiographic technique to localize phosphoinositide hydrolysis (PI) in the rat spinal cord dorsal horn. The lateral half of laminae I-II showed the highest levels of baseline PI turnover and carbachol-stimulated PI turnover in normal animals as well as after inflammation. Inflammation resulted in increased baseline PI turnover in this region of the ipsilateral (76%) and contralateral (65%) dorsal horns. Carbachol increased P… more
Date: May 2002
Creator: Moore, Jack
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Neuronal Network Analyses in vitro of Acute Individual and Combined Responses to Fluoxetine and Ethanol

Description: Embryonic murine neuronal networks cultured on microelectrode arrays were used to quantify acute electrophysiological effects of fluoxetine and ethanol. Spontaneously active frontal cortex cultures showed highly repeatable, dose-dependent sensitivities to both compounds. Cultures began to respond to fluoxetine at 3 µM and were shut off at 10-16 µM. EC50s mean ± S.D. for spike and burst rates were 4.1 ± 1.5 µM and 4.5 ± 1.1 µM (n=14). The fluoxetine inhibition was reversible and without effect… more
Date: August 2002
Creator: Xia,Yun
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Use of Satellite Imagery and GIS to Model Brood-Rearing Habitat for Rio Grande Wild Turkey Populations Occurring in the Western Cross Timbers Region of Texas

Description: Remote sensing and GIS have become standard tools for evaluating spatial components of wildlife habitats. These techniques were implemented to evaluate Rio Grande wild turkey (Meleagris gallopavo) poult-rearing habitat in the Western Cross Timbers region of Texas. Texas Parks and Wildlife (TPWD) random roving turkey counts for 1987-1989 and 1998-2000 were selected, indicating locations where hens with poults were observed. Satellite imagery from 1988 and 1999 was classified and then processed w… more
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Date: August 2002
Creator: Miller, Christopher J.
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Functional Neural Toxicity and Endocrine Responses in Mice Following Naphthalene Exposure

Description: Polycyclic aromatic hydrocarbons (PAHs) are a well studied and diverse class of environmental toxicants. PAHs act via the aryl hydrocarbon receptor (AhR), and studies have suggested that PAHs may elicit neurological and estrogenic effects. Doses of PAHs between 50 to 150 ppm may elicit neurotoxicity in rodent models. The present study investigated the effects of naphthalene on in vivo steroidogenesis in Swiss Webster male mice, and in vitro neural function of Balb-C/ICR mice frontal cortex ne… more
Date: August 2010
Creator: Colbert, Crystal
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College Freshman Biology Two Semester Course: Integrating Deep Processing Teaching Techniques

Description: Development of a college level freshman biology course was undertaken in response to government reports that American students have fallen behind students of other countries in the area of the sciences. Teaching strategies were investigated to accomplish two objectives, to define essential academic material to include in the course and to investigate teaching techniques that would increase deep processing of the information. An active process that consisted of applying the cognitive information… more
Date: May 2002
Creator: Blevins, Mary Jean
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