Browsing Research Fellows Theses by Issue Date
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Petrich, Christine (August 16, 2006)[more][less]
Abstract: The eventual outcome of spinal cord injury is largely influenced by damage that occurs after the injury. Damaged connections between spinal cord cells and the brain allow a positive feedback mechanism to go unchecked when activated by ascending pain messages. Over-excitation then causes secondary damage. This study examines whether a pharmacological manipulation that should attenuate over-excitation reduces the adverse effects of shock treatment. Rats received spinal impact injuries and, the next day, were given the NMDA receptor antagonist MK-801 (0.08 mg/kg, i.p.) or its vehicle before receiving either a bout of uncontrollable stimulation or identical treatment without the stimulation itself. Their hindlimb motor activity was monitored for 21 days. Results indicate a significant effect of the drug on rats that received uncontrollable stimulation. The study has clinical implications for the treatment of spinal cord injuries in humans. URI: http://handle.tamu.edu/1969.1/3701 Files in this item: 1
PetrichThesis.pdf (329.8Kb) -
Krueger, Brandon (August 16, 2006)[more][less]
Abstract: Almost unique in the world, chattel slavery persists in Sudan into the 21st century. The U.N. and various NGOs have provided evidence that slavery exists in modern Sudan and that the government has done little, if anything, to stop it. The efforts of NGOs to stop slavery have largely failed, and perhaps even fueled the slave trade by paying to free slaves, which created a market for them. This thesis examines the complex history of Sudan that led to 2006, analyzes modern abolishment efforts to discover why they have failed, and develops a solution based on a Nations’ “Hierarchy of Needs” that can be applied in Sudan and is practical on political, economic, and cultural levels. My history analysis hinged on a review of academic texts, government documents, credible journalism, and slave testimonials. Recurring patterns in that history were identified and explained so as to provide a basis of issues, which the solution must address. I adapted Maslow’s Hierarchy of Needs to define three necessities, Security, Sovereignty, and Economy, and two sustaining needs, Identity and Adaptation. Each need is reliant on its predecessors in the Hierarchy and when employed together, will successfully build Sudan into an economic and diplomatic partner of the world. The establishment of security and peace in Sudan are fundamental to cutting off slave trading routes and establishing Sudan’s sovereignty and subsequent improved diplomatic relations. The Sudanese government can then use these improved diplomatic relations to help diversify their economy through foreign investment and international trade based on improving labor standards for export quotas, which will reduce slave markets through moral spillover from industry leaders who were forced to improve labor standards to stay in business. Economic growth fosters a national identity that provides the impetus for Sudan to undergo a moral reform that may lead to a final crackdown on slavery. The resultant solution can be applied to Sudan in 2006 or at any point in Sudan’s progress in the future, but will be most effective if applied to establishing security in Darfur and built from that peace. URI: http://handle.tamu.edu/1969.1/3702 Files in this item: 1
Solving Slavery in Sudan.pdf (1.703Mb) -
Woodruff, Christopher (August 16, 2006)[more][less]
Abstract: The purpose of this study is to investigate the internment and detainment policies used by Presidents Franklin D. Roosevelt and George W. Bush as methods for protecting the United States from attack during World War II and the War on Terror. This study comes from a desire to better understand Bush’s decision to use indefinite detainment as a tool in the War on Terror, and in looking for an historical precedent, Roosevelt’s internment of Japanese Americans appeared to possess many similar characteristics. Therefore, through direct comparison and analysis of historical and legal sources, this research highlights major similarities and differences that existed between the two episodes. Roosevelt’s Executive Order 9066 affected the lives of over 120,000 people and over 70,000 U.S. citizens. Decades of anti-Asian sentiment, the public hysteria that erupted following Pearl Harbor, and the racially-biased suspicions of disloyalty, all played a role in Roosevelt’s ultimate decision to give the Secretary of War the authority to evacuate and incarcerate the ethnic Japanese population on the West Coast. Similarly, Bush responded to the September 11 attacks by advocating the need for indefinite detainment of hundreds of terrorism suspects, both U.S. citizen and non citizen. He also issued the Military Order of November 13, 2001, which gave substantial power to the Secretary of Defense to detain, charge, and try suspects, but did not require that they be charged. Through analysis of initial FBI arrests, public opinion trends, prisoner treatment, and Supreme Court cases, this research allows its readers to consider the thesis that Roosevelt’s and Bush’s actions represent a pattern of presidential decisions that might conflict with human and constitutional rights. URI: http://handle.tamu.edu/1969.1/3703 Files in this item: 1
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Williams, Jennifer (August 16, 2006)[more][less]
Abstract: The present study examined the effect of context reinstatement on the recovery of experimentally blocked memories and the possible creation of memory errors. Context refers to every aspect of the environment in which a to-be-remembered event has taken place. Physically returning to a learning context, or creating a mental representation of it, may allow one to use context information as a source of memory cues to enhance memory performance. This is referred to as context reinstatement. Research shows that memory performance is best if learning and testing conditions match, rather than if they are mismatched (Smith, 1979; Thomson & Tulving, 1970). It is unclear if context reinstatement can influence not only the enhancement of continuously accessible memories, but whether it might also help with the recovery of blocked memories. Also, because mentally reinstating context is a form of mental imagery, it is possible that this process of reinstatement would lead to the creation of memories for imagined events or memory errors. To examine these questions the present study manipulated mental and physical reinstatement and examined both accurate and inaccurate memories. The present study included three phases. First, participants performed an incidental learning task with a series of word lists in one context. Next, participants performed either memory interference tasks for three of the learned lists or distracter tasks in a different context. Lastly, participants completed a series of memory tests in either the first or second context, with or without context reinstatement. Results showed strong blocking effects in the forget condition groups. Recovery effects were stronger in the physical reinstatement group, as compared to the other groups. Interestingly, memory errors were similar across experimental groups. Thus, physical, but not mental, context reinstatement aided in the recovery of blocked memories, but the use of mental reinstatement did not lead to memory errors. Results may edify other memory researchers, forensic investigators and clinical psychologists who may use forms of context reinstatement and mental imagery for memory enhancement or recovery purposes. URI: http://handle.tamu.edu/1969.1/3704 Files in this item: 1
Thesis.pdf (143.1Kb) -
Asonye, Adora (August 16, 2006)[more][less]
Abstract: Although many use misogynistic, materialistic, and violent lyrics in attempt to belie the notion that hip hop contains any manifestations of romantic love, I contend that not only is romantic love present in hip hop, but the love exhibited does not deviate substantially from common notions of romantic love in mainstream society. Using a definition of romantic love derived by classic explorations in the subject, romantic love will be explored in hip hop culture. URI: http://handle.tamu.edu/1969.1/3705 Files in this item: 1
misogyny and myth.doc (132.6Kb) -
Shafer, Christina (August 16, 2006)[more][less]
Abstract: Histology, though widely used for cellular imaging, suffers from its destructive nature; cells are not viewed in their natural living environment. Nonlinear optical microscopy (NLOM) has been widely used to view cells in situ without a need for sample processing. NLOM uses a high-powered ultrafast laser to generate nonlinear optical signals within living tissue. These signals are used to render two- and three-dimensional images. One improvement to be made on this imaging system is the capability to produce spectral images rather than merely intensity images. Spectral information provides insight to the sample’s chemical environment; this insight may lead to increased efficiency in disease diagnosis, since pathological development begins at the iv microscopic level. Additional detectors added to the system will allow wavelength discrimination and the creation of spectral images. To achieve this type of system, additional hardware must be built and software must be written to allow simultaneous data acquisition from 32 detectors. The initial task competed involved the scanning mechanism; a program was created to control motorized optical scanning mirrors. The next task required a circuit board to be built to interface the detectors with the computer. A sub-program was then designed to save tissue response matrices (images) as binary files. The files were able to be opened in MATLAB® and converted into scaled intensity images. The final program created used information from the circuit board (i.e. from each detector) to create the response matrix to be saved as a binary file. All hardware and software was then integrated into the current imaging system to be tested with two detectors. At this point, the new system cannot adequately render images. Future work will involve software and hardware correction until images are correctly formed. At this point, the tissue response to two different ranges of light wavelengths will able to be viewed separately, and the matrices can be added to create a grayscale image. At this point, work on this project will involve expanding the hardware and software to incorporate 30 additional detectors. The spectral detection system will allow image v segmentation of biological components, and chemical markers associated with cellular abnormalities as well as different genetic markers can be viewed on a microscopic level. Therefore, this system is of great value to medicine and science. URI: http://handle.tamu.edu/1969.1/3706 Files in this item: 1
thesis2.pdf (2.056Mb) -
Bosshard, John (August 16, 2006)[more][less]
Abstract: Microscale devices capable of manipulating fluids have potential to give rise to a paradigm shift in the fields of biology and medicine. The purpose of this research is to assess the feasibility of applying single echo acquisition (SEA) magnetic resonance imaging (MRI) to microscale fluid flow quantification. This is important because development and improvement of microfluidic devices requires the ability to accurately and non-invasively measure microscale flow. Lab-on-a-chip aims to integrate an array of chemical laboratory tools onto a single chip, utilizing microfluidic flow for mass transport. Use of microfluidics results in improved speed and efficiency and allows operations that harness physical properties unique to the microscale. Current microscale flow visualization methods rely on fluorescence, requiring optically non-opaque fluids and device boundaries. Furthermore, these methods require insertion of labeled chemicals or seed particles into the flow, which may interfere with processes under observation. MRI has an established history of non-invasively quantifying flow through opaque boundaries but is limited by its slow image acquisition rate. SEA employs a 64-channel array coil to acquire a full image with each echo, significantly improving temporal resolution. Methods involve assessing the performance of SEA flow velocimetry on a scale of several millimeters by utilizing time-of-flight techniques. By taking a series of 5 ms snapshots, quantitative velocity information is obtained for laminar, transitional, and turbulent flow with Reynolds numbers ranging from 100 to 1200. Findings show that the turbulent eddies are visible and velocity information can be extracted from images, which means that SEA can accurately asses flow at the millimeter scale. In addition, SEA allows visualization of turbulent flow not accessible to standard MRI velocimetry techniques. It is concluded that SEA could be adapted as new tool for non-invasive quantification of optically inaccessible flow. Implications of this are that through integrated radio frequency microcoils, SEA MRI could be adapted as a new tool to study microfluidic flow resulting in improved microfluidic devices. URI: http://handle.tamu.edu/1969.1/3707 Files in this item: 1
Bosshard Thesis Formatting-Revised.pdf (2.352Mb) -
McKay, Joshua L. (August 16, 2006)[more][less]
Abstract: This is the first step in a series of studies to test the feasibility of using Raman Spectroscopy (RS) to non-invasively detect physiologically relevant blood alcohol concentrations. Blood tests, urine tests, and the breathalyzer are currently the most commonly used techniques to measure blood alcohol content. Blood tests are invasive and require wet labs. Although urine tests are non-invasive, they also require wet labs. The breathalyzer is non-invasive and does not require a lab, but its accuracy has come into question. This method measures alcohol content in the alveolar air, which is not always a reliable predictor of alcohol content in the blood. A Raman-based technique could alleviate these problems and eventually replace or complement the breathalyzer. To explore this option, samples of ethanol-in-water from 0-1.0% (wt/vol) were prepared, and a time study was performed to test both the ability of RS to detect alcohol in relatively short amounts of time and to find an optimum scanning time. The spectra were used to create a partial least squares (PLS) model, which uses differences in the spectra to construct a model to describe the relationship between certain peaks and alcohol concentration. The model was used to predict the concentration of several known samples. The accuracy of the model’s prediction was compared for each stage of the time study. This study then focused on measuring ethanol concentrations in plasma, a much more complicated media than water. Again, a model was constructed, used to predict alcohol concentrations, and tested for accuracy. This study showed that Raman spectroscopy has the ability to detect alcohol in the physiological range in rather complex environments and in limited time windows, but repeatability is the main question. Spectra have a tendency to be inconsistent at such low alcohol concentrations, which results in a weak model and less accurate predictions. Description: Undergraduate Research Fellows Thesis URI: http://handle.tamu.edu/1969.1/3708 Files in this item: 1
Fellows Thesis.pdf (240.3Kb) -
Zhang, Xujia (August 16, 2006)[more][less]
Abstract: The ultimate goal of this research is to develop an online, non-destructive, incipient fault detection system that is able to detect incipient faults in transformers and other electric equipment before the faults become catastrophic. With the condition assessment capability of the detection system, operators are equipped with better information during their decision-making process. Corrective actions are taken prior to transformer and equipment failures to prevent down-time and reduce operating and maintenance costs. Diagnosis of data associated with incipient failures is essential to develop an efficient, non-destructive, and online system. Field testing data were collected from controlled experiment and simulation data from mathematical models are studied. This thesis presents a data-mining approach to analyze field recorded and simulation data to characterize incipient fault data and study its properties. A supervised classifier using neural network (NN) toolbox in Matlab provides an efficient and accurate classification method to separate monitoring signal data into clusters base on their properties. However, raw data collected from the field and simulations will create too many dimensions and inputs to the neural network and make it a complex and over-generalized classification. Therefore, features are extracted from the data set, and these features are formed into feature clusters in order to identify patterns in signals as they are related to various physical behaviors of the system. The similarity between recognized patterns and patterns shown in future monitoring signals will trigger the warning of initializing or developing faults in transformers or equipment. This thesis demonstrates how different features were extracted from the raw data using various analysis techniques in both time domain and time-frequency domain, and the design and implementation of a neural network-based classification method. The classifier outputs are classes of data being separated into groups based on their characteristics and behaviors. Meaning of different classes is also explained in this thesis. URI: http://handle.tamu.edu/1969.1/3709 Files in this item: 1
ThesisFinalVersion(Xujia Zhang).pdf (785.1Kb) -
Myers, Sherry (August 16, 2006)[more][less]
Abstract: During the late eighteenth century and early nineteenth centuries, the Anglo-American Atlantic world saw a rise in the number and popularity of museums as cultural institutions. By concentrating on the premier museums in each culture, the British Museum and Charles Willson Peale’s Philadelphia Museum, this project seeks to establish two things: 1) the circumstances that allowed museums to become a vanguard in the British and American societies of 1750-1820, and 2) the kinds of changes museums instigated upon assuming a role of significant cultural influence. The social climate of these two populations was such that museums were able to assume a function fashioned by contemporary social conditions. The impacts of the Enlightenment, a rising middle classes, and the creation of a consumer culture coalesced to set the stage for museums to become a force of significant social influence. As these museums gained in popularity, they began to influence their surroundings. They became forums for social change, serving as institutions of education that aimed to instruct both the erudite elite and the “curious” in matters of virtue as well as in matters of intellect. Museums offered a new form of popular entertainment and provided an environment that fostered social mingling between classes. Furthermore, these museums altered their audience’s perceptions of their many worlds, including the natural world, their own culture and national identity, and the world of the “others” that existed outside their borders, particularly the Amerindian, African, and South Pacific cultures. The British Museum and the Peale Museum were used in their respective societies as tools to cultivate a unifying definition of “Britishness” or “Americanness” by creating their own image in opposition to the “others” and by using elements of natural history to instill a sense of pride in the homeland. The institutions’ directors took advantage of the popularity and influence the museums had assumed in their respective cultures and used them to better and strengthen those societies. URI: http://handle.tamu.edu/1969.1/3710 Files in this item: 1
Museum culture.pdf (629.9Kb) -
Garbacz, Robert Scott (August 16, 2006)[more][less]
Abstract: Visual illustrations were critical to Tolkien's creativity—they preceded his creation of lexical texts, helped to define the world in which he set most of his literature, and continued to hold a great significance in the publication of Tolkien's texts. Yet the one essay Tolkien wrote in an attempt to bridge the gap between his career as a Medieval philologist and his hobby of creating fantasy stories, “On Fairy-stories”, actively condemned the illustrations that Tolkien was then creating. “In human art, Fantasy is a thing best left to words,” (Tolkien, Reader 70) and even when art is set in support of words, “illustrations do little good to fairy-stories.” (Tolkien, Reader 95) While Tolkien offers a small number of theoretical arguments against fantasy illustrations in “On Fairy-stories,” it is my assertion that such an opinion represents Tolkien's particular personal and historical position rather than an authoritative understanding of the nature of his own art. In my undergraduate honors thesis, I am proposing an alternative to Tolkien's conclusion about the value of his illustrations by showing that Tolkien's illustrations served a critical role in the formation of his literary creations of fantasy. My methodology is to combine a chronologically disciplined close reading of his illustrations with a brief overview of those of Tolkien's writings that intersect with his interest in illustration. I trace the evolution of Tolkien's visual work through: (1) childhood creation of realistic illustrations in which Tolkien developed his ability to comment upon the world; (2) early fantasy illustrations, which predated Tolkien’s fantasy texts but themselves present one-image visual “stories” with philosophical implications and openness similar to his later fantasy texts; (3) illustrations for Tolkien’s “legendary history,” in which he created a geography of emotional landscapes through which he could move the characters of his fantasy texts; and (4) illustrations for children’s stories, in which Tolkien reintroduced the humor, character, and satire from his childhood illustrations to his fantasy fiction. I not only argue that illustrations are a significant companion to Tolkien's lexical texts, but also that they provide another perspective on the study of illustrations. URI: http://handle.tamu.edu/1969.1/3711 Files in this item: 1
Thesis sans illustrations.pdf (380.7Kb) -
Mackey, Jessica (August 16, 2006)[more][less]
Abstract: Methylmercury has cytotoxic effects on animals and humans and a major target organ for methylmercury is the central nervous system (CNS). Methylmercury (MeHg) is a developmental neurotoxicant and the prenatal CNS appears to be even more sensitive to MeHg than the mature CNS. Previous research has shown that high doses of MeHg have severe cellular and behavioral effects. More recently, concern has been raised with respect to possible deleterious effects of chronic low doses of MeHg exposure to the developing CNS. The objective of this study was to determine if chronic low dose MeHg exposure would result in deficits in cognition and coordination and a decrease in mitochondrial membrane potential in cerebellar granule cells. Pregnant mice were divided into control and treatment groups. Developing fetuses were exposed to chronic low doses of MeHg through feeding food containing MeHg to pregnant C57Bl/6J female mice at a daily dose of 0.03 µg/Kg of body weight. Footprint analysis, rota-rod, vertical pole, open field and Morris water maze were used to test for changes in coordination, activity levels, spatial learning and memory. Differences were observed between control and MeHg groups in rota-rod, footprint analysis, open field and Morris water maze. The results follow below. Controls stayed on the rota-rod twice as long as treated mice on the last day of trials. Left and right foot angles were decreased in treated mice. Treated females displayed less rearing movement in the first five minutes of open field compared to both treated males and the controls. In the Morris water maze, treated mice took longer than controls to find the platform on days 1-4. The probe trial results indicated that treated mice swam significantly less than the controls. Cerebellar granule cells were isolated using dissociation media containing DNAse, and mitochondrial membrane potential was measured on the acutely isolated cells using tetramethylrhodamine methylester fluorescent dye. Images were captured with a fluorescence microscope. The data indicated no significant differences in fluorescence between control and MeHg mice. These conclusions indicate prenatal in vivo methylmercury exposure in mice may not significantly impair mitochondrial membrane potential; however, other abnormal neuronal functions lead to the subtle changes in motor and cognitive behavior described in this research. As a consequence, other cellular mechanisms must be delineated to understand how prenatal methylmercury exposure causes CNS pathogenesis. URI: http://handle.tamu.edu/1969.1/3712 Files in this item: 1
pdf thesis.pdf (945.2Kb) -
Whitaker, Jodi (August 16, 2006)[more][less]
Abstract: This study examines how the genders of both student writers and their peer tutors affect the dynamics of writing tutoring sessions and influence the student writers’ subsequent evaluations of their peer tutors. Even though peer tutors employed the same non-directive, facilitative approach with all students, students judged female tutors to exhibit stereotypically feminine characteristics and male tutors to exhibit stereotypically masculine characteristics. Students also more highly evaluated the peer tutor whose sex matched their own. Students who were more highly sex-typed (masculine males and feminine females) more highly evaluated the same-sex peer tutor than did less sex-typed students of the same gender, though feminine female students more strongly exerted this preference than did masculine male students. Evidence gathered from post-session Likert surveys, paired observations, and semi-structured telephone interviews supported all three hypotheses. Reasons concerning why sex stereotypes still shape tutoring sessions as well as implications for altering tutor training policy are explored. URI: http://handle.tamu.edu/1969.1/3713 Files in this item: 1
Jodi Thesis (Modified).doc (1.054Mb) -
Nelson, John (August 16, 2006)[more][less]
Abstract: While the collapse of communist rule and process of transitioning to democracy in the former-Soviet Union and its numerous satellite states certainly warrants the wealth of attention received, by no means does this signal that the history of communist state rule is ended. Contrary to popular belief—and even belief in academe it sometimes seems—Communism still survives. In fact, a number of Asian states still claim to follow the path to a promised societal utopia under the guidance of their respective Politburos and may be described as not only ‘surviving’ but thriving, experiencing economic stability and enjoying high rates of growth. This study examines the ramifications of economic and political reform policies implemented by four collapsed communist regimes which have transitioned to democratic governance—the former-Soviet Union, Poland, Hungary, and Czechoslovakia—as well as two surviving Asian communist regimes—Vietnam and China—in identifying characteristic patterns of reform that are conducive to regime survival and/or collapse. The end objective herein is to provide projections for the future of the Castro regime in Cuba, which faces a critical juncture in the future with the impending death of its charismatic leader. I hypothesize that economic reform, through consistent implementation, generates credibility for both Communist Party elites and their future reform endeavors. Additionally, reform packages that manage to successfully stabilize the economy bestow an increased measure of legitimacy to the political elite, allowing the Communist Party to maintain political control, thereby avoiding collapse and the transition to democracy. The third and final section contains general discussion and what conclusions can be drawn from the results, as well as analysis of the history of reform efforts to present in the Caribbean island state of Cuba. URI: http://handle.tamu.edu/1969.1/3714 Files in this item: 1
Nelson - Fellows Thesis.doc (228.8Kb) -
Blakley, John David (August 16, 2006)[more][less]
Abstract: Control over reproduction is obviously not the only component in the fight for women’s equality. However, control over one’s body is essential to control over one’s destiny. This control is essential for a person desiring to be an equal member of society. At the time the United States was founded, reproductive control was not fettered by the state. Unfortunately, however, the nineteenth century brought about restriction and regulation of reproduction. As a result, a fight for reproductive control for women has occurred in the United States ever since. This struggle includes three separate but interrelated aspects: birth control, abortion, and sterilization. In the early nineteenth century, U.S. women, uninhibited by government intervention, were free to control conception as they saw fit, albeit with inconsistent methods. Using conceptual morality as their central argument, some religious and political leaders, as well as many in the medical field, condemned various forms of contraception. By the end of the century, this disapproval had produced laws regulating access to birth control. The battle for birth control culminated in 1965 when the Supreme Court ruled in Griswold v. Connecticut that a constitutionally-guaranteed right to privacy protected the use of birth control. Controversy over birth control still continues today, however, with debates spotlighting government funding for birth control and access to emergency contraception. In 1800 there was not one law in the United States regulating abortion. Federal and state law reflected the common law notion that an abortion induced before quickening was a matter of a woman controlling her body. Within the next one hundred years, however, the federal government and every state had regulated, or even outlawed, abortion. The 1973 Supreme Court case Roe v. Wade declared that the Constitution protects a woman’s right to choose whether or not to bear a child. Today, this guarantee of a constitutional right to abortion still stands, but is less than secure. Compulsory sterilization laws in the United States were enacted due to the theory of eugenics, or the science of the improvement of the human race by better breeding. Primary targets of forced sterilization were the mentally ill and repeat offenders. In the1927 case Buck v. Bell, the Supreme Court gave explicit approval of eugenic sterilization. The 1942 case Skinner v. Oklahoma specifically ruled against punitive sterilization. The last documented forced sterilization in the United States occurred in 1981. URI: http://handle.tamu.edu/1969.1/3715 Files in this item: 1
finalthesis.doc (400.3Kb) -
Baig, Kimberlyn Maravet (August 16, 2006)[more][less]
Abstract: ABSTRACT Site Directed Mutagenesis of Severe Acute Respiratory Syndrome (SARS) Cornavirus Nsp 15 Endoribonuclease (April 2006) K. Maravet Baig Department of Biology Texas A&M University Fellows Advisor: Dr. Linda A Guarino Department of Biology, Biochemistry, and Entomology In 2002-2003 SARS Coronavirus (SARS- CoV) spread throughout the world resulting in a 10% death rate. With little known about SARS-CoV, research must be done in order to understand the viral mechanism for structure based drug design in the future. The purpose of this research is addition to the current body of knowledge concerning SARS-CoV proteins, especially that of the Nsp15 endoribonuclease and its activity. Nsp15 is a non-structural protein of SARS-CoV with endoribonuclease activity. Nsp15 recognizes and cleaves at uracil with a Mn2+ cofactor; (Endoribonucleases cut in the interior of RNA strands). It was hypothesized that the uracil recognition may be indicated by four conserved asparagine residues. To test this, one of the conserved asparagine residues was mutated for analysis. Site directed mutagenesis of Nsp15 with a QuickChange kit was performed. The 4th asparagine, N, was mutated to alanine in one sample and to serine in another sample, making N4A and N4S mutants respectively. The 4th amino acid was chosen due to the flanking amino acid’s known ability to affect activity. Nsp15 forms a hexamer, if the mutation caused the hexamer conformation to be disrupted, activity would be affected. N4A and N4S mutant proteins were created, and their catalytic activities were tested. N4F, another mutant protein was tested, where phenylalanine replaced asparagine in the 4th amino acid position. Dilutions of the three mutants were tested in order to compare the mutant activity with the wild type Nsp15 activity. N4S and N4A showed activity, but the N4F mutant did not. Since N4F had no activity, it was inferred that the mutation caused a conformational change in the protein thereby affecting activity. Since hexamerization is protein concentration dependent, different concentrations should be tested in order to find out if the protein is active at higher concentration, or if it forms hexamers. A determination of the binding affinity of the mutant Nsp 15 for the known co-factor Mn2+ should also be conducted as well as the examination of conformational changes brought about by addition of Mn2+. Lastly, failure to bind the RNA substrate may cause inactivity; this possibility should also be tested. Description: Honors Undergraduate Research Fellows Thesis URI: http://handle.tamu.edu/1969.1/3716 Files in this item: 1
maravet thesis complete.pdf (1.406Mb) -
Chandler, Megan (August 16, 2006)[more][less]
Abstract: Baumrind (1971) developed one of the two major traditions of Parental Acceptance/ Rejection Theory, in which she categorizes parenting styles into authoritarian, authoritative, and permissive categories. Research indicates that culture, ethnicity and socioeconomic status influence a family’s tendency toward a particular parenting style. This study investigated how different parenting styles experienced, as reported by university students, relate to students’ academic self-efficacy. We hypothesized that student-report of an authoritative parenting style would be associated with self-report of higher academic self-efficacy and relatively higher academic performance. Unlike previous studies assessing the relations between parenting style and academic self-efficacy, which have used samples of children and adolescents, this sample consisted of university students in developmental transition in independent living. In addition, we explored the extent to which ethnicity and family variables would be related to student-reported parenting style, achievement, and self-efficacy. We sampled students (n=264) enrolled in introduction to psychology courses at Texas A&M University. Participants received 1 course grade credit for their participation. Students’ typically were older adolescents/young adults (M=19.27 years, SD=1.52) and most were in their first and second year of college (M=1.63 year). All participants completed a packet of questionnaires in counterbalanced order. A Demographic Questionnaire was used to gather data on gender, age, ethnicity, year in college, study skills habits, GPA, and family description. The Parental Authority Questionnaire was used to measure Baumrind’s parental prototypes as reported to have been experienced by the students. The Self Efficacy and Study Skills Questionnaire was used to obtain self-report of academic self-efficacy. Analyses indicated that academic self-efficacy was significantly positively correlated with GPA. Also, as hypothesized, academic self-efficacy was significantly positively correlated with authoritative parenting style. Based on regression analyses, authoritative parenting style and academic self-efficacy were significant predictors of academic performance, after controlling for gender. In an increasingly complex and rapidly changing world, college academic success is an important aspect of human development. Identifying and understanding family background variables that contribute positively to college achievement and academic self-efficacy yield suggestions for navigating the crucial transition from adolescence to young adulthood. URI: http://handle.tamu.edu/1969.1/3717 Files in this item: 1
finalhonorsthesis.doc (608.7Kb) -
Han, Shuo (August 16, 2006)[more][less]
Abstract: Brucella spp. are gram-negative, facultative intracellular pathogen that causes an infectious and contagious bacterial disease, brucellosis, in humans and animals. Previous research showed that lipopolysaccaride (LPS) is a classically demonstrated virulence mechanism in Brucella. The main objective of this project was to design an inducible system that would allow or prevent the expression of LPS using the manBA genes which encode components of LPS through the regulation of different promoters, pTac and araC. This will allow us to better understand the significance of LPS expression and its link to virulence. If we are able to regulate the expression of LPS in smooth and rough strains, we will be able to further understand these differences and eventually help to create attenuated vaccines against brucellosis. Construction of manBA expression vectors using pTac and araC promoters was carried out in the E. coli strain, DH10B as well as the conditions required for induction of manBA expression. The constructs were transferred into a Brucella melitensis (16M) manBA deletion mutant to determine optimal induction conditions. During the induction, specific time points were monitored for variations in manBA expression. Methods used to detect manBA expression include: acriflavine agglutination, SDS-PAGE followed by staining and Western Blots. Results showed that LPS expression could be regulated by pTac and araC promoters under specified induction conditions. Although the pTac promoter was found to be leaky, we were able to induce LPS expression in Brucella melitensis with the addition of glucose to the growth medium. The araC promoter construct was more tightly regulated than the pTac promoter and required DMEM, a defined media for expression. Therefore, we have developed two inducible systems which would aid in the study of LPS virulence mechanism in Brucella. Future work will include infecting murine macrophages using the inducible Brucella constructs to study intracellular trafficking and survival of the transformed bacteria. Construction of manBA expression vectors using pTac and araC promoters was carried out in E. coli strain, DH10B The conditions required for induction of manBA expression were tested for the respective promoters in E. coli DH10B. The constructs were transferred into Brucella melitensis (16M) manBA-knockouts to carry out induction under experimentally determined conditions in Brucella. During the induction, specific time points were monitored for variations in manBA expression. Methods used to detect manBA expression include: Acriflavine agglutination, SDS-PAGE followed by staining and Western Blots. Results show that LPS expression can be regulated by pTac and araC promoters under specified induction conditions. Although the pTac promoter was leaky, we were able to induce LPS expression in Brucella melitensis with the help of glucose. The araC promoter construct was more tightly regulated than the pTac promoter and required DMEM, a defined media for expression. Therefore, we have developed two inducible systems which would aid in the study of LPS virulence mechanism in Brucella. We also used a special staining method of the SDS-PAGE to detect LPS production. Future work will include infecting murine macrophages using the inducible Brucella constructs to study intracellular trafficking and survival of the transformed bacteria. URI: http://handle.tamu.edu/1969.1/3718 Files in this item: 1
Shuo Han thesis.pdf (619.5Kb) -
Hardin, Elizabeth Ashley (August 16, 2006)[more][less]
Abstract: Stressful life events have been linked to the onset, susceptibility, and even progression of neurodegenerative diseases such as multiple sclerosis (MS). Theiler’s murine encephalomyelitis virus (TMEV) infection, a well-characterized animal model of MS, is used in our laboratory to investigate the interaction between social stressors and disease development. Social disruption (SDR), a model of social stress used in our laboratory, appears to worsen Theiler’s virus infection through excessive inflammation. Prior findings from our laboratory indicate that pro-inflammatory cytokine IL-6 is partially mediating the negative effects of SDR in the development of Theiler’s virus infection. In order to examine the role of other pro-inflammatory cytokines, our objective was to develop techniques to block the cytokines TNF-α and IL-1β. Prior studies have indicated stress-induced release of these cytokines (TNF-α and IL-1β) may mediate the adverse effects of disease development in subsequent immune challenges. Balb/cJ mice were implanted with a permanent indwelling cannula in the left lateral ventricle of the brain and allowed to recover for one week prior to manipulations. Once the animals recovered from cannulation surgery, neutralizing antibody to TNF-α or IL-1β was administered during the period of SDR. Antibody-SDR treatments continued for one week. Mice were sacrificed the morning following last day of SDR. Brains and sera were collected to measure TNF-α or IL-1β levels. Spleens were harvested to examine the development of glucocorticoid resistance (GCR), a hallmark of SDR, in the TNF-α study only. The ELISA assay was not sensitive enough to the tissue levels of TNF-α, therefore successful antagonism was undetectable. In contrast, IL-1β was elevated during SDR; however, it appears that the antibody was only partially effective at the dose administered. The GCR assay indicated that resistance occurred in antibody treated and control mice in the TNF-α study, signifying that antibody treatment does not interfere with the development of normal social stress effects. Future studies are necessary to identify an effective blocking dose for the neutralizing antibody to IL-1β. In addition, we also need to develop alternative assays, such as RT-PCR or an RNase protection assay, that are sensitive to the levels of TNF-α associated with SDR. URI: http://handle.tamu.edu/1969.1/3719 Files in this item: 1
Ashley no-add GOOD VERSION.pdf (213.5Kb) -
Wilson, Mary J (August 16, 2006)[more][less]
Abstract: Coxiella burnetii is a gram negative, obligate intracellular bacterium. It is the etiologic agent of Q fever in a variety of species including livestock, humans and arthropods. The bacterium infects the monocytes of its host and is encapsulated in the phagolysosome, an acidic vacuole meant to kill the bacterium, where it survives and replicates. C. burnetii must be able to acquire all the nutrients necessary for survival within this acidic environment. In all but one species of bacteria, iron has been shown as necessary for replication as is serves as a cofactor for many cellular processes. However, iron concentration must be maintained as a delicate balance. Too little iron and replication is impeded, while too much iron initiates the production of oxygen radicals which are fatal to the cell. Ferric iron Uptake Regulator (Fur) is responsible for the regulation of iron acquisition genes in many gram negative bacteria. Fur acts as a transcriptional repressor of iron regulated genes. These genes have a sequence within their promoter region called the “Fur box” that binds to the Fur protein when the protein is also bound to its co-repressor, Fe2+. In E. coli, Fur has been found responsible for the regulation of over 30 genes. Previous work showed that C. burnetii has a functional fur gene. We hypothesize that C. burnetii genes that contain promoters with a highly conserved consensus sequence are part of a Fur regulon. Our goal is to characterize this regulon. Nineteen putative Fur boxes were identified in C. burnetii. Fifteen of these were cloned into the pBlue plasmid expressing beta-galactosidase. These plasmids were then co-transformed with a plasmid expressing Fur into an E.coli fur deletion strain. The β-galactosidase assay was then used to test promoter activity. Eleven of these promoters were evaluated. Three promoters, for open reading frames CBU0970, CBU0769 and feoB were found to be repressed in the presence of iron. We predict that although a Fur regulon is present in C. burnetii, it includes only a limited set of genes. URI: http://handle.tamu.edu/1969.1/3720 Files in this item: 1
Thesis FINAL-published.doc (513.5Kb)
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