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 Collection: UNT Theses and Dissertations
The Effect of Menthol on Nicotine Metabolism:  a Cross Species Evaluation

The Effect of Menthol on Nicotine Metabolism: a Cross Species Evaluation

Date: December 2013
Creator: Pace, Wendy Lee
Description: The effect of menthol on nicotine metabolism was examined in liver S9 fractions of four different species and in the in vivo mouse model. The purpose of this study was to investigate three parameters: (1) biotransformation of nicotine to cotinine in various species (human, mouse, rat and trout) using in vitro methods; (2) to determine if the addition of menthol with nicotine altered biotransformation of nicotine to cotinine; (3) and to assess similar parameters in an in vivo mouse model. The major findings of this study include: (1) mice appear to metabolize nicotine, over time, in a manner similar to humans; (2) menthol decreased cotinine production, over time, after a single dose in mice; and (3) menthol increased cotinine production, over time, after repeated doses, in mice.
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Laser Surface Modification on Az31b Mg Alloy for Bio-wettability

Laser Surface Modification on Az31b Mg Alloy for Bio-wettability

Date: December 2013
Creator: Ho, YeeHsien
Description: Laser surface modification of AZ31B Magnesium alloy changes surface composition and roughness to provide improved surface bio-wettability. Laser processing resulted in phase transformation and grain refinement due to rapid quenching effect. Furthermore, instantaneous heating and vaporization resulted in removal of material, leading the textured surface generation. A study was conducted on a continuum-wave diode-pumped ytterbium laser to create multiple tracks for determining the resulting bio-wettability. Five different laser input powers were processed on Mg alloy, and then examined by XRD, SEM, optical profilometer, and contact angle measurement. A finite element based heat transfer model was developed using COMSOL multi-physics package to predict the temperature evolution during laser processing. The thermal histories predicted by the model are used to evaluate the cooling rates and solidification rate and the associated changes in the microstructure. The surface energy of laser surface modification samples can be calculated by measuring the contact angle with 3 different standard liquid (D.I water, Formamide, and 1-Bromonaphthalen). The bio-wettability of the laser surface modification samples can be conducted by simulated body fluid contact angle measurement. The results of SEM, 3D morphology, XRD, and contact angle measurement show that the grain size and roughness play role for wetting behavior of ...
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Relationships of Benthic Macroinvertebrate Community Structure with Land-use, Habitat, In-stream Water Chemistry, Depositional Sediment Biofilm Fatty Acids, and Surfactants in the Effluent Dominated Texas Trinity River

Relationships of Benthic Macroinvertebrate Community Structure with Land-use, Habitat, In-stream Water Chemistry, Depositional Sediment Biofilm Fatty Acids, and Surfactants in the Effluent Dominated Texas Trinity River

Date: December 2013
Creator: Slye, Jaime L.
Description: The Trinity River is an urbanized, effluent-dominated river, and is heavily relied upon for drinking water. The benthic macroinvertebrate community has been monitored for over 20 years, with the focus of this dissertation on three studies (1987-88, 2005, and 2011). Water quality improvement following dechlorination resulted in increased benthic metrics. Overall habitat quality, in-stream cover, surface water total organic carbon, sediment total organic carbon, near-field urban land-use, near-field forested land-use, surface water surfactant toxic units, and depositional sediment biofilm fatty acids all have statistically significant relationships with benthic macroinvertebrate metrics. These relationships are better defined with increased taxonomic resolution at the genus/species level for all benthic taxa, including Chironomidae and Oligochaeta. It is recommend that benthic identifications for state and city water quality assessments be done at the genus/species level. A novel method for quantifying depositional sediment biofilm fatty acids has been produced and tested in this dissertation. Benthic metrics are directly related to fatty acid profiles, with several essential fatty acids found only at upstream sites.
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Using a Multimodal Sensing Approach to Characterize Human Thermal Comfort Level

Using a Multimodal Sensing Approach to Characterize Human Thermal Comfort Level

Date: December 2013
Creator: Wicaksono, Cakra Aditya
Description: A method to distinguish human level of comfort has been developed by using a thermal camera, physiological sensors, and a surroundings sensor. The method has successfully collected data from hominal facial features, breathing rate, skin temperature, room temperature, blood volume pressure, relative humidity, and air velocity. Participants from all genders and races were involved in two sessions of a human comfort experiment including a psychology survey session. The variables, such as room temperature and clothing are controlled to maintain steady test conditions. The region of interest was determined by body temperature and facial temperature as registered by the thermal imaging camera. To experience different levels of discomfort, participants were required to perform two different activities. The first session included an activity on the air resistance elliptical and the second session required the subjects to remain steady in front of a fan. The data was subsequently compared on all subjects to determine whether human discomfort and comfort can be predicted by using various approaches. The parameters of discomfort and comfort were simulated to characterize human levels of comfort. According to arrangement of correlation among thermal comfort responses, blood volume pressure, skin temperature, respiration, and skin conduction, we are be able to ...
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Adolescent Behavior Problems and Interparental Conflict: the Moderating Role of Parent-child Attachment

Adolescent Behavior Problems and Interparental Conflict: the Moderating Role of Parent-child Attachment

Date: December 2013
Creator: Daubs, Carlyn
Description: The current study examined the role that parent-child attachment plays in the relationship between marital conflict and the development of behavior problems in adolescents. To evaluate the hypothesis that attachment moderates this relationship, 57 families were recruited via e-mail invitation sent to families that participated in local church youth groups, school organizations, and a treatment program designed for adolescents with behavior problems. One custodial parent and his/her adolescent child completed an online or paper version of a survey consisting of the Achenbach’s Behavior Checklists, the Inventory of Parent and Peer Attachment, and the Children’s Perception of Interparental Conflict Scale. Hypotheses were evaluated using Baron and Kenny’s (1986) procedures to test moderating effects with multiple regression analyses. Mother attachment demonstrated a significant moderation effect between the intensity of interparental conflict and the parent’s report of externalizing behavior problems. Specifically, at low conflict intensity levels, relative to low attachment security, high attachment security was associated with fewer externalizing behavior problems, whereas at high intensities of interparental conflict high attachment security was associated with more externalizing behavior problems.
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Examining High School Coaches’ Likelihood to Refer To, Interest in Working With, and Plans to Hire a Sport Psychologist

Examining High School Coaches’ Likelihood to Refer To, Interest in Working With, and Plans to Hire a Sport Psychologist

Date: December 2013
Creator: Austin, Harlan
Description: The primary goal of the current study was to extend previous research suggesting that coaches are the primary gatekeepers who may be a barrier to working with athletes by examining high school coaches likelihood to refer to, interest in, and intention to hire a sport psychologist. Specifically, the current study examined relationships between high school coaches’ sex, age, and type of sport coached (i.e., contact vs. non-contact) and their likelihood to refer athletes to a sport psychologist for a variety of presenting issues (i.e., poor attentional focus, poor leadership, family issues, etc.). It also examined relationships between coaches’ sex, age, and type of sport coached (i.e., contact vs. non-contact) and their interest in working with a sport psychologist. Finally, the study examined reasons why coaches did not plan to hire a sport psychologist. An examination of the possible reasons that high school coaches do not plan to hire a sport psychologist served an exploratory purpose. Participants included 450 coaches who coached high school sports in the United States. Results indicated that female coaches and non-contact sport coaches were more likely to refer athletes to a sport psychologist for a variety of referral issues than male coaches and coaches of contact ...
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Josephus’ Jewish War and the Causes of the Jewish Revolt: Re-examining Inevitability

Josephus’ Jewish War and the Causes of the Jewish Revolt: Re-examining Inevitability

Date: December 2013
Creator: Lopez, Javier
Description: The Jewish revolt against the Romans in 66 CE can be seen as the culmination of years of oppression at the hands of their Roman overlords. The first-century historian Josephus narrates the developments of the war and the events prior. A member of the priestly class and a general in the war, Josephus provides us a detailed account that has long troubled historians. This book was an attempt by Josephus to explain the nature of the war to his primary audience of predominantly angry and grieving Jews. The causes of the war are explained in different terms, ranging from Roman provincial administration, Jewish apocalypticism, and Jewish internal struggles. The Jews eventually reached a tipping point and engaged the Romans in open revolt. Josephus was adamant that the origin of the revolt remained with a few, youthful individuals who were able to persuade the country to rebel. This thesis emphasizes the causes of the war as Josephus saw them and how they are reflected both within The Jewish War and the later work Jewish Antiquities. By observing the Roman provincial administration spanning 6-66 CE, I argue that Judaea had low moments sprinkled throughout the time but in 66 there was something ...
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Funds of Knowledge in a Hispanic Household: a Case Study of Family Experiences, Values, and Connections to Education

Funds of Knowledge in a Hispanic Household: a Case Study of Family Experiences, Values, and Connections to Education

Date: December 2013
Creator: Feild, Kelly A.
Description: Traditionally, the field of education has often adopted a negative perspective in their views of minority families’ contributions to the educational progress of their children. However, research embodying the theoretical framework of ‘funds of knowledge’ attempts to counter that model through its assertion that all families possess extensive bodies of knowledge that have developed through social, historical, and cultural contexts. Teachers carry out studies of familial funds of knowledge in order to understand how family experiences shape the knowledge that a child brings to the classroom. There is then, the potential to use that body of knowledge to create meaningful learning experiences that connect prior understanding and experiences to classroom practice. This research served as a case study of the funds of knowledge existing in the home of a Hispanic family and the connections that existed between that knowledge and literacy. The results indicated that the family possessed extensive funds of knowledge that developed through their historical, cultural, and social experiences. They often used family networks, as well as formal and informal literacy experiences to share this knowledge with their children. A key component of the literacy value system that they communicated resulted from a desire to maintain aspects of ...
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Effects of Airway Pressure, Hypercapnia, and Hypoxia on Pulmonary Vagal Afferents in the Alligator (Alligator Misssissippiensis)

Effects of Airway Pressure, Hypercapnia, and Hypoxia on Pulmonary Vagal Afferents in the Alligator (Alligator Misssissippiensis)

Date: December 2013
Creator: Marschand, Rachel E.
Description: The American alligator (Alligator mississippiensis) is an aquatic diving reptile with a periodic breathing pattern. Previous work has identified pulmonary stretch receptors (PSR), both rapidly- and slowly-adapting, and intrapulmonary chemoreceptors (IPCs) that modulate breathing patterns in alligators. The purpose of the present study was to identify the effects of prolonged lung inflation and deflation (simulated dives) on PSR and/or IPC firing characteristics in the alligator. The effects of airway pressure, hypercapnia, and hypoxia on dynamic and static responses of pulmonary stretch receptors (PSR) were studied in juvenile alligators (mean mass = 246 g) at 24°C. Receptor activity appeared to be a mixture of slowly-adapting PSRs (SARs) and rapidly-adapting PSRs (RARs) with varying thresholds and degrees of adaptation, but no CO2 sensitivity. Dives were simulated in order to character receptor activity before, during, and after prolonged periods of lung inflation and deflation. Some stretch receptors showed a change in dynamic response, exhibiting inhibition for several breaths after 1 min of lung inflation, but were unaffected by prolonged deflation. For SAR, the post-dive inhibition was inhibited by CO2 and hypoxia alone. These airway stretch receptors may be involved in recovery of breathing patterns and lung volume during pre- and post-diving behavior and ...
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Population Dynamics of Zebra Mussels (Dreissena Polymorpha) in a North Texas Reservoir: Implications for Invasions in the Southern United States

Population Dynamics of Zebra Mussels (Dreissena Polymorpha) in a North Texas Reservoir: Implications for Invasions in the Southern United States

Date: December 2013
Creator: Churchill, Christopher J.
Description: This dissertation has two main objectives: first, quantify the effects of environmental conditions on spatio-temporal spawning and larval dynamics of zebra mussels (Dreissena polymorpha [Pallas 1771]) in Lake Texoma, and second, quantify the effects of environmental conditions on survival, growth, and reproduction of young of the year (YOY) juvenile zebra mussels. These biological responses directly influence population establishment success and invasive spread dynamics. Reproductive output of the zebra mussel population in Lake Texoma was significantly related to water temperature and lake elevation. Annual maximum larval (veliger) density decreased significantly indicating a population crash, which was likely caused by thermal stress and variability of lake elevation. In 2011, temperatures peaked at 34.3°C and lake elevation decreased to the lowest level recorded during the previous 18 years, which desiccated a substantial number of settled mussels in littoral zones. Estimated mean date of first spawn in Lake Texoma was observed approximately 1.5 months earlier than in Lake Erie, and peak veliger densities were observed two months earlier. Veligers were observed in the deepest oxygenated water after lake stratification. During a 69-day in situ experiment during summer in Lake Texoma, age-specific mortality of zebra mussels was generally high until temperatures decreased to approximately 28°C, ...
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