Theses

SAUDI LEARNERS’ PRONUNCIATION DIFFICULTIES WITH THE ENGLISH VOICELESS BILABIAL STOP /p/

Khalaf Naif Alharbi — Thu, 11 Apr 2013 10:34:41 PDT

This study investigated the production of the English voiceless bilabial stop /p/ in three word positions (initial, medial, and final). By a group of 20 male and female ESL Saudi Arabian learners in the United States. The stimulus of this work was a list of 20 English words with an equal number of words for the three word positions initial, medial, and final. By measuring the Voice Onset Time in word initial and the duration of the release of the target phoneme /p/ in word medial and final positions this study identified several types of error in the participants’ utterances, including substitution of /p/ with /b/, approximation, and frication. The position of /p/ in words had a significant effect on the accuracy of pronunciation as the position that yielded the highest level of accuracy was the final position. The other two positions, initial and medial, showed a significantly higher number of production errors than word- final position.

Effect of Time Constraint on Second Language Reading Comprehension

Hammad Alshammari — Wed, 20 Mar 2013 13:32:48 PDT

This study aimed to investigate the role of time constraint on second language reading comprehension via the recruiting of 47 Saudi participants who were learning English as a second language. Subjects shared similar level of English proficiency; all participants were in their third semester of English at Aljouf University, Saudi Arabia, at the time of data collection. Participants were divided into three time groups; limited (20 minutes), extended (30 minutes), and unlimited (40 minutes). In terms of stimuli, a reading text was adapted from a standard English proficiency exam, TOEFL. The text consisted of 699 words and was of moderate level in difficulty, calculated as between 8th and 9th grade for native English speakers; passive structures comprised 6% of the text. Questions were also divided into three groups to elaborate the effect of time constraint on each type of questions. The particulars of the study were as follows. Firstly, this study analyzed effect of time constraint on the overall performance on the TOEFL reading passage. Then, effect of time on the three groups, including vocabulary-based questions, literal comprehension questions, and higher order inferential questions. Results revealed that time constraint tends to be an affective factor in reading. In the overall comparison among the 3 different time groups, the unlimited time group showed the highest performance on the reading comprehension task. ii In view of the categories of questions, no significant difference was found on the vocabulary-based questions between time condition groups. The overall low vocabulary scores across groups and the lack of significant effect for time constraint suggest that extended time does not compensate for poor vocabulary knowledge. On the other hand, the unlimited time group demonstrated the best performance relative to the other two groups on the literal comprehension and higher order questions. Of all three categories, the higher-order questions were the most difficult for all three time constraint groups. Overall, the results of this study show that time given to the reading task significantly affects overall reading comprehension scores, but they also suggest that this effect varies in relation to the types of questions.

SYLLABIFICATION OF SINGLE INTERVOCALIC CONSONANTS IN THE ARABIC DIALECT OF SAKAKA CITY: EVIDENCE FROM A NONWORD GAME

Mamdouh Zaal M Alhuwaykim — Wed, 20 Mar 2013 13:00:20 PDT

This paper offers a short report on an Optimality Theoretic analysis of the syllabification of single intervocalic consonants in the Arabic dialect of Sakaka city. This study aimed at investigating how intervocalic consonants of different sonority profiles are treated in the dialect of Sakaka City. Thirty monolingual male participants were recruited voluntarily in this study. Participants’ judgments were elicited using a metalinguistic word blending task with pairs of disyllabic nonwords of the structure ꞌCVCVC + ꞌCVCVC, where stress was on the first syllable only throughout the data. All phonemes involved in this structure are in conformity with Arabic phonotactics. In addition, the intervocalic consonants under examination belonged to four sonority levels; glides ([j] and [w]), liquids ([r] and [l]), nasals ([m] and [n]) and obstruents ([s] and [b]). The low vowel [a] was the only vowel used in this structure. Unlike many works of this nature, ambisyllabicity and word minimality effects were blocked in this complete word task. Although the investigation shed light on several important universal rules of syllabification, sonority profile of intervocalic consonants was the overriding preference in this blending task. That is, glides, liquids and nasals were parsed in coda position by the majority of participants whereas obstruents were parsed in onset position. However, the effects of other universal principles of syllabification such as Maximal Onset Principle and stress placement were minimized. The study concluded that the Split Margin Hierarchy adopted showed a strong preference for coda parse with high sonority consonants and onset parse with low sonority ones, thus adding further support to the abstractness of the syllable as a higher prosodic constituent and the discreteness of phonemes in the human speech stream.

Keywords: Arabic dialect, Sakaka city, Optimality Theory, intervocalic consonants, nonwords, ambisyllabicity, minimality effects, Split Margin Hierarchy, sonority, Maximal Onset Principle, stress, syllable, speech stream.

The Acquisition of the Nongeneric Uses of the English Definite Article the by Arabic Speakers of English

Aied M. Alenizi — Thu, 14 Mar 2013 12:29:11 PDT

This study aimed to investigate the acquisition of the four non-generic uses of the English definite article the by Arabic learners of English in Saudi Arabia. These non-generic uses included textual, situational, cultural and structural. This study had three goals: (1) to determine whether these uses are acquired in a certain sequence; (2) to explore which one of these uses is the most difficult and the easiest in learning; (3) to investigate whether one or two of the uses are overused.

The instrument consisted of 59 sentences adopted from Liu and Gleason (2002). There were 40 instances for required uses and 20 sentences for obligatory nonuse (5 instances for each use). The subjects were instructed to insert the where they deemed it necessary. The participants were 45 male undergraduate English major students, whose ages ranged from 18 to 22 with a Mean age of 21.6, from a university in Saudi Arabia. They were divided into three groups (15 students each) based on their proficiency levels as follows; low intermediate, intermediate, and advanced. The results revealed developmental trends in the acquisition of the non-generic uses of the English definite article related to proficiency. Specifically, the advanced group showed significantly higher accuracy of use in all four functions. Regarding the four functions, the order of acquisition, based on level of accuracy was as follows: situational, cultural, structural and textual. The study results are discussed in view of their pedagogical implications for the teaching of the definite article to Saudi learners of English.

MACROINVERTEBRATE RESPONSES TO REMOVAL OF RIPARIAN WOODY VEGETATION ALONG TALLGRASS PRAIRIE STREAMS

Jodi Marie Vandermyde — Wed, 06 Mar 2013 07:27:23 PST

Woody vegetation encroachment has become a major threat to tallgrass prairie streams mainly because of fire suppression. This process converts prairie streams from open to closed canopy systems. The effects of these riparian changes are poorly understood, but the relative importance of basal resources presumably shifts from primarily autochthonous to allochthonous with increasing canopy cover, potentially altering macroinvertebrate functional structure and production. To assess the effects of woody vegetation encroachment on stream ecosystem structure and function, riparian trees were removed from two headwater stream reaches on the Konza Prairie Biological Station (KPBS) in eastern Kansas. Experimental stream reaches were compared to streams with naturally open and closed canopies before and after the manipulation. Benthic organic matter and macroinvertebrates were collected monthly from each reach for one year before and one year after woody vegetation removal. Total community production in canopy removal reaches ranged from 8.9-10.2 g AFDM m-2 y-1 before riparian removal, and this increased significantly to 13.4-14.5 g AFDM m-2 y-1 after riparian removal. Scraper production in canopy removal reaches was 2.8-3.9 g AFDM m-2 y-1 before riparian removal, and increased significantly to 6.0-8.7 g AFDM m-2 y-1 after riparian removal, presumably due to enhanced food availability. Total community production in naturally open reaches ranged from 7.6-12.6 g AFDM m-2 y-1 before riparian removal and decreased to 6.5-9.8 g AFDM m-2 y-1 after riparian removal. Riparian forest removal altered macroinvertebrate production and functional structure, but higher macroinvertebrate production in canopy removal reaches compared to naturally open reaches suggested natural conditions were not restored one year after riparian removal. However, macroinvertebrate communities in naturally open and canopy removal reaches became more similar after riparian removal. Functional structure, based on production, in naturally open and canopy removal reaches after riparian removal was dominated by scrapers (45-60% of total production), with similar proportions of collector-gatherers (12-26%) and predators (15-25%). Collector-filterers and shredders contributed < 9% of total production in naturally open and canopy removal reaches after riparian removal. Results demonstrate that woody vegetation encroachment and riparian forest removal significantly influence tallgrass prairie stream structure and function. Information from this study can help inform and guide management, restoration, and conservation of remaining tallgrass prairie streams.

Use of Alternative Lipids and Finishing Feeds to Improve Nutritional Value and Food Safety of Hybrid Striped Bass

Curtis Crouse — Wed, 06 Mar 2013 07:27:21 PST

Seafood represents the most important source of long-chain polyunsaturated fatty acids (LC-PUFAs) in the human diet. However, consuming fish can present risks from persistent organic pollutants (POPs) that bioaccumulate in edible tissues following dietary exposure. In farmed fish, POPs accumulate as a result of feeding diets based on fish oil (FO). Fish oil substitution can reduce POP accumulation, but also results in loss of beneficial LC-PUFAs. Fish oil-based finishing diets at the end of production can restore LC-PUFAs, but this strategy also increases POPs. The present study assessed the use of saturated fatty acid (SFA)-rich lipids to replace fish oil in grow-out feeds in conjunction with a fish oil-rich finishing diet to determine if this strategy could produce hybrid striped bass with equal production performance, equivalent LC-PUFA levels, and reduced POP concentrations. Triplicate tanks of hybrid striped bass were raised on diets containing fish oil (100% FO), fish oil spiked with additional POPs (100% FO Spike), or blends (50/50 or 25/75) of FO and coconut (CO) or palm (PO) oils (50% CO, 50% PO, 75% CO, 75% PO) with and without an eight week finishing period with the 100% FO diet prior to harvest. Production performance, fillet LC-PUFA, and POP content were assessed. Production performance was not adversely affected by any of the feeding regimens. However, fatty acid profile was altered, with fillets of fish consuming less fish oil having lower LC-PUFA and POP levels. Finishing yielded a modest increase in fillet LC-PUFAs and POPs, but POPs accumulated more readily than LC-PUFAs during finishing. However, harvest fillet POP and LC-PUFA levels in the experimental groups were lower relative to levels in the 100% FO group. Replacing fish oil in aquafeeds can produce fish with reduced LC-PUFAs, and also reduced POPs. Feeding fish oil results in more rapid accumulation of POPs than LC-PUFA. Overall, the 75% fish oil replacement feeds yielded fish with the highest ratio of LC-PUFAs to POPs. Despite lower LC-PUFA content, fillets of fish fed the 75% fish oil replacement feeds could be incorporated into a weekly meal plan with other dietary sources of LC-PUFAs to meet dietary recommendations for these essential nutrients.

Staging Crave, a play by Sarah Kane

Gabriela Ponce — Wed, 06 Mar 2013 07:27:18 PST

Crave, the play I chose to direct as my thesis final project, constitutes a complex and crude portrait of our time, a moment in history marked by violence and individualism. These themes permeate the whole script, with its experimental and poetic style constitutes a challenge at the moment of staging it. This document is intended precisely to register the whole process of staging Crave. The first chapter presents the pre-production research, in which I trace the artistic trajectory of the author, British playwright Sarah Kane, in the context of experimental theater. I also analyze the play, and I present my directorial approach to it. In the second chapter I register the actual process of staging it; the methodologies I used in working with the actors and the designers, as well as the challenges I faced in applying them. Finally, the last chapter is a reflection upon the whole process, with the intention of evaluating my growth as a theater director through this project, which constitutes my final step in these training years at SIUC.

Assessing Cognitive Rehabilitation Following Bilateral Frontal Traumatic Brain Injury in Rats Using the T-Maze

Amanda Marie Wright — Wed, 06 Mar 2013 07:27:12 PST

Cognitive rehabilitation has been shown to have beneficial effects on functional recovery following traumatic brain injury. In the present study, the rehabilitative effects of cognitive training in the T-maze on functional recovery of behavior and cortical sparing following a cortical impact injury (CCI) were examined. T-maze alternation has a widespread application in detecting cognitive dysfunction, and alternation in particular utilizes working memory. 47 male Sprague-Dawley rats were divided into six groups (sham trained, sham yoked, sham control, injured trained, injured yoked, injured control). Injured animals received a bilateral frontal craniotomy (1.0 A/P, 0.0 M/L from Bregma). The cortices were depressed at a depth of 2.5 mm at a velocity of 3 m/s. T-maze training began on post surgery day 2 and continued daily through post surgery day 19. Following this rehabilitative T-maze training, cognition was assessed using two different memory tasks in the Morris water maze (MWM).

Vicarious Perceptions of Post-Traumatic Growth

Megan Kloep — Wed, 06 Mar 2013 07:27:11 PST

Research related to positive psychological reactions following exposure to traumatic events, also known as post-traumatic growth (PTG), has suggested that support from others can facilitate such outcomes. The current study focused on whether people's perceptions of PTG differed based on the gender of a hypothetical survivor and nature of the trauma. Characterological differences amongst those who perceive growth as being more, or less, likely was also of interest. Perceptions of growth were measured in relation to three possible traumatic scenarios (vignettes) that were randomly assigned to participants. Following the vignette, participants completed a variety of self-report measures. Contrary to previous PTG literature, there were no consistent characterological differences among participants who did, and who did not, perceive growth as a possible outcome following trauma exposure. PTG was not related to nature of the trauma or gender of the survivor. Implications for clinical practice and future directions for research are discussed.

Foraging for Demand: Applying Optimal Foraging Theory to Decisions in a Simulated Business Context

Jared Lee Klotz — Wed, 06 Mar 2013 07:27:08 PST

Charnov's (1976) marginal value theorem has had success in predicting that animals will optimize net rate of gain when foraging in a patchy environment. The present study attempts to apply the marginal value theorem (MVT) to human behavior in a business setting in 3 Experiments. Businesses also attempt to optimize net rate of gain when choosing to discontinue one product in lieu of another using a product life cycle (PLC). Experiments 1 & 2 attempted to assess human behavior in a business context by varying time necessary to retool and monetary cost of retooling respectively. Experiment 3 attempted to add ecological validity by introducing variability to the PLC. The results of Experiments 1, 2, & 3 indicate that the MVT does not accurately predict human behavior in a business context, though methodological issues may have affected these results. Future research must be conducted in this area.

EFFECTS OF EXPERIMENTAL STORM SURGE AND SEDIMENTATION ON PITCHER PLANTS (SARRACENIA PURPUREA) AND ASSOCIATED ASSEMBLAGES IN A COASTAL PINE SAVANNA

Matthew John Abbott — Wed, 06 Mar 2013 07:27:06 PST

Sea-level rise and stronger hurricanes associated with global climate change will likely result in farther reaching storm surges that will greatly affect coastal ecosystems. These surges can transport nutrients, salt water, and sediment to nutrient poor, fresh (i.e. low salinity) pine savannas. Purple pitcher plants (Sarracenia purpurea ) are pine savanna inhabitants that could potentially be at a disadvantage because their pitcher morphology and stout structure may leave them prone to collecting saline water and sediment after a surge. In this study, separate field and greenhouse experiments were conducted to test the effects of storm surge water salinity and sediment type on pine savanna soil characteristics, plant community structure, and pitcher plant vitality. In the field, plots (containing &ge genet of S. purpurea ) were experimentally storm surged with fresh or saline water crossed with one of four sediment types (local, foreign, fertilized foreign, or no sediment). Saline water inundation resulted in significantly higher pitcher plant mortality than the fresh water treatment combinations. However, a subsequent prescribed fire and regional drought affected the study area during the next growing season, resulting in the decline of all the pitcher plants to zero or near zero percent cover. Soil data revealed that the combination of salt water and fertilized sediment resulted in short-term increases in soil-water conductivity and nitrogen availability. Interestingly, there were no significant differences in plant community structure between treatments, suggesting that the community as a whole is not as vulnerable as the pitcher plants to the cumulative effects of multiple stressors (i.e. storm surge, fire, and drought) operating in this system. Indicator species analysis revealed that some species were significant indicators of certain treatments; thus suggesting that pitcher plants are not the only species affected by storm surge. In the greenhouse, pitcher plants received various forms of sediment (i.e. no sediment, sterile sediment, or one of two levels of fertilized sediment) within their pitchers to determine if nutrient uptake is either inhibited or enhanced. Plants that received sterile sediment had higher carbon:nitrogen ratios and higher leaf mass per unit area. Eutrophic sediment deposition resulted in a temporary decrease in relative growth rate as well as changes in pitcher morphology. There were no differences in chlorophyll content and photosynthetic rates between treatments. Both the field and greenhouse experiments indicate that global climate change may indirectly contribute to the further decline of southeastern purple pitcher plant populations in the future.

PATTERNS IN ENVIRONMENTAL DRIVERS OF WETLAND FUNCTIONING AND SPECIES COMPOSITION IN A COMPLEX PEATLAND

Jeremy A. Graham — Wed, 06 Mar 2013 07:27:05 PST

The boreal peatlands that cover much of western Canada are immense reservoirs of organic carbon and nitrogen, serving as sinks for atmospheric carbon, as well as providing habitat for flora and fauna, and nutrient cycling. These ecosystems are generally believed to be nitrogen limited. Due to regional increases in industrial activities associated in the Athabasca Oil Sands Region (AOSR), atmospheric deposition of nitrogen is projected to increase, with unknown effects on peatland functioning. The results of this study provide baseline data for a nitrogen fertilization experiment with an accurate site description of the entire peatland complex to provide reference for the experiment. This study also examines patterns in production and nitrogen usage along a wet to dry gradient. My main question was if species assemblages could be sorted into communities and how these were related to environmental gradients. In chapters three and four I asked how production and nitrogen usage and storage varied along a moisture gradient. In chapter two, four communities were identified as being independent with clear indicator species. These communities had differences in abiotic factors formed clear gradients across the peatland, influencing the distribution of species arrangements in the peatland complex. Sphagnum angustifolium thrived in all four communities and across the entire range of gradients. This species is a foundation of species of bogs and poor fens and was studied in more detail in chapters 3 and 4. In chapter three, I found that primary production of S. angustifolium increased from dry to wet along the moisture gradient. Cranked wires used to measure linear growth became less reliable in wetter habitats, missing over 50 % of growth measure by innate time markers. Capitula increased in biomass throughout the course of the growing season, suggesting that after vertical elongation, S. angustifolium begins to accumulate branches and leaves in the capitula to close the growing season. Chapter four, evaluating nitrogen requirements found that while primary production of S. angustifolium increased from dry to wet, tissue quality of the growth decreased along this gradient. Despite the lower tissue quality, wet habitats had higher nitrogen requirements to support growth rates. Inputs of atmospheric deposition fulfilled <5% of annual N requirements and nitrogen saturated capitula in the beginning of the season was found to be an important source of nitrogen for growth, as capitula nitrogen storage declined over the season. Of the total nitrogen assimilated into annual growth, the percent lost a year later was similar across the moisture gradient; more nitrogen is stored in the wet habitats, strictly due to higher amounts initially assimilated. The results of this study suggest that in drier peatland habitats, there is an insufficient supply of water to deliver nitrogen and to support continuous growth during the growing season. Consequently, in wetter habitats, production is limited by nitrogen while in drier habitats it is limited by climate.

EVALUATION AND GENETIC ANALYSIS OF TWO SOYBEAN [Glycine max (L.) Merr.] RECOMBINANT INBRED LINE POPULATIONS SEGREGATING FOR RESISTANCE TO ROOT KNOT NEMATODE (Meloidogyne incognita)

Drew Welsey Wright — Wed, 06 Mar 2013 07:27:02 PST

One of the most economically important pathogens of US soybeans is the Southern Root Knot Nematode [(Meloidogyne incognita) (Kofoid and White) Chitwood] (Mi). Evaluation and identification of resistance is highly important to the plant breeding program at SIUC. The main objective of this study was to screen within the greenhouse two F5:7 recombinant inbred line (RIL) (n=96) from crosses between LS90-1920 or LS97-1610 (resistant parents) with `Spencer' (susceptible parent) to identify sources of resistance for Mi. Additionally, the RILs were evaluated in two locations in southern Illinois (Harrisburg and Dowell) in 2011 for several agronomic characteristics including yield performance. The phenotypic data collected from field and greenhouse experiments was used to select for superior lines within the two populations. The screening data was also used to identify single nucleotide polymorphism (SNP) markers associated with Mi resistance. Initial screening of the 5,361 SNP markers indicated four SNP markers (ss247062763, ss247064854, ss247077423 and ss247067293) highly associated with resistance to Mi. The results will help accelerating selection practices, and have provided high yielding resistant lines for the creation of resistant commercial varieties.

Imagination in the Philosophy of Josiah Royce

Jennifer Lynn Roche — Wed, 06 Mar 2013 07:26:56 PST

That Josiah Royce's philosophy relies on imagination has been acknowledged, but there has not yet been scholarship behind what this argument consists of or implies, both for imagination and Roycean loyalty. This project works to examine how imagination works in Royce's philosophy and, in particular, the ethical system of loyalty, as imagination serves in the creation and perfection of loyalty. The first level of this explores Royce's psychological groundwork for imagination and how this works into the development of the self. From there, this project works with the connections of aesthetics and beauty to Roycean loyalty, with particular interest in how beauty aids in the self's choice of cause. The final level of this project is concerned with how imagination informs the community and how imagination aids in the development of loyalty to a lost cause and thus loyalty to loyalty.

RHOX8 ABLATION USING A NOVEL SIRNA TRANSGENIC MOUSE MODEL YIELDS DOWN REGULATION OF SEX-DETERMINATION GENE, SOX9

Matthew Grauden Davis — Wed, 06 Mar 2013 07:26:54 PST

The Reproductive Homeobox X-linked, Rhox, genes encode transcription factors that are expressed exclusively in the testis, epididymis, placenta, and ovary and are therefore good candidates to regulate postnatal reproductive events. The founding member of this 33 gene cluster Rhox5, previously known as Pem, is important in male mice for both spermatogenesis and sperm maturation. This is supported by the findings that Rhox5-null mice are hypofertile due to increased apoptosis of meiotic germ cells in the testis as well as motility defects in epididymal sperm. Rhox5 was also the first homeobox gene to exhibit stage specific androgen sensitivity exclusive to Sertoli cells during spermatogenesis. Within the Rhox family, only RHOX8 shows expression in Sertoli cells at time intervals similar to that of RHOX5. Interestingly, while Rhox8 exhibits high expression in Sertoli cells it does not appear to be dependent upon androgens for transcription. The co-localization of these genes supports the hypothesis that RHOX5 and RHOX8 may exhibit partially redundant functions in the testis, and potentially explain why Rhox5-null animals are subfertile and not infertile. However, due to the androgen dissimilarity between Rhox5 and Rhox8 aforementioned it is possible that RHOX8 also exhibits functionally unique expression in the male gonad as well. Therefore, we sought to ablate Rhox8, and potentially derive Rhox5/Rhox8 double knockouts to better assess these questions. However, due to the proximity of Rhox5 and Rhox8 on the X chromosome, recombination of individual knockout lines produced by traditional strategies would be unlikely to succeed. To circumvent this issue, we used a novel tissue-specific RNAi approach to knockdown RHOX8 in vivo. Our knockdown system used the Rhox5 proximal promoter which contains regulatory elements for expression of the Rhox8-siRNA transgene in Sertoli cells. Candidate siRNAs were evaluated for knockdown of RHOX8 in Sertoli cell lines, and the most efficient was used to produce 11 independent founder lines. Among these founders the majority of the males failed to produce any subsequent litters. However, backcrossed littermates from female founder lines have exhibited knockdown of RHOX8 in total testis lysates using Western blot analysis. Immunohistochemical analysis confirmed Sertoli cell specific RHOX8 protein knockdown as well as knockdown of Sertoli cell marker, SOX9. However, other control targets, GATA1, AR, and RHOX5; maintain normal expression patterns. Rhox8-knockdown and Sox9-regulation was also observed at the mRNA level via real-time qPCR, showing significant knockdown of both transcripts when compared to wild-type animals. Further characterization revealed that this single knockdown of RHOX8 sufficiently yields a subfertile phenotype. Therefore, the central hypothesis of this study is that RHOX8 is imperative for normal sperm output, an essential gene regulator in the adult testis, and possibly employs an important role during embryonic testis development.

FOXO1 Expression in Human Pituitary Adenomas

Corrie Lynn Farris — Wed, 06 Mar 2013 07:26:52 PST

FOXO1 is a forkhead transcription factor that inhibits proliferation and promotes apoptosis. It regulates genes that are involved in many diverse processes, including regulation of cell proliferation and cancer. The goal of our research is to understand FOXO1 and the role that it plays in human pituitary adenomas. Three objectives were outlined in this project to help determine the expression of FOXO1 in human pituitary adenomas. The first objective of this project was to analyze the spatial and temporal pattern of FOXO1 during mouse pituitary development. Objective one results showed that starting at e12.5, FOXO1 is cytoplasmic and becomes more nuclear later on in development. Immunohistochemical co-staining of FOXO1 and bromodeoxyuridine (BrdU) showed that FOXO1 does not co-localize with BrdU at e12.5, e14.5, and e16.5 showing that FOXO1 is not expressed in actively proliferating cells. The goal of objective two was to determine if expression levels of FOXO1 were abnormal in human pituitary adenomas. The results of objective two showed that when compared to FOXO1 expression in human normal pituitaries, FOXO1 was decreased in gonodotropinomas, null cell adenomas, and prolactinomas. In corticotropinomas, FOXO1 expression was increased while in somatotropinomas, FOXO1 expression was the same as compared in human normal pituitaries. Objective three was to assess whether spatial distribution of FOXO1 protein is abnormal in human pituitary tumor tissue. Our data showed that statistically there is no difference in FOXO1 spatial distribution between pituitary and normal samples. Overall, our real time RT-PCR data showed that FOXO1 expression is reduced in human gonadotropinomas, null cell adenomas, and prolactinomas. FOXO1 expression was increased in human cortiocotropinomas while it remained the same in human somatotropinomas. Immunohistochemistry staining revealed that statistically there was no difference in FOXO1 expression in the human pituitary samples when compared to human normal pituitary samples. These findings lead to the idea that loss of FOXO1 may help contribute to human pituitary tumorigenesis but more than likely other factors are involved.

THE UPTAKE AND TRANSPORT OF NANOPARTICLES IN THE MURINE SMALL INTESTINE

Mark Joseph Murskyj — Wed, 06 Mar 2013 07:26:51 PST

The small intestine is a mucosal surface that is exposed to a large number of antigens from food and commensal organisms and preferentially develops a state of unresponsiveness or tolerance to these antigens. Epithelial cells take up soluble antigens leading to the development of oral tolerance. Goblet cells are also capable taking up soluble antigen. M cells, known for the uptake of particulate antigen, are found primarily in the follicle-associated epithelium, which is not critical for oral tolerance. To determine whether intestinal epithelial cells (IECs) take up particulate antigen, fluorescent nanoparticles 0.02 - 2 μm in diameter were administered to mice. It was found that IECs and goblet cells take up nanoparticles ≤40 nm in diameter and these nanoparticles are rapidly transported to the mesenteric lymph nodes, an organ important for the induction of tolerance to dietary antigens and immunity to pathogens.

EGD2 is a conserved telomere binding protein

Amrita Biswas — Wed, 06 Mar 2013 07:26:50 PST

Telomeres are essential for the stability of the eukaryotic genome. Disruption of telomere function leads to chromosomal abnormalities and is implicated in human cancer and aging. The simple guanine-rich repeats of telomeres are maintained by telomerase, and several telomere binding proteins are known to regulate telomerase activity. The extreme terminus of the guanine-rich strand, the substrate to which telomerase must gain access and extend, exists as a single-strand overhang that varies in length in step with the cell cycle. In vitro these telomeric single strand sequences readily adopt guanine-quadruplex structures which purified telomerase has reduced ability to bind for extension. S. cerevisiae Cdc13 is one of several telomeric proteins known to melt telomeric guanine-quadruplexes and thereby promote telomerase activity in vitro. Our lab identified a human nuclear protein with DNA binding properties similar to S. cerevisiae Cdc13; namely, the ability to bind and melt telomeric G-quadruplexes and purine motif triplexes in vitro. The activity was purified and identified as the nascent polypeptide associated complex (NAC), a heterodimer comprised of NACa; and BTF3 subunits. The goal of the present study was to determine whether or not the S. cerevisiae homologues of NAC (Egd2) and BTF3 (Egd1) are enriched at telomeres in vivo, and if so, to characterize NAC's function at the telomere. Our study demonstrates that S. cerevisiae Egd2 is preferentially enriched at telomeres, although evidence for Egd1 enrichment at telomeres was not observed. This may indicate that an Egd2 homodimer, rather than an Egd2-Egd1 heterodimer, localizes to telomeres. Preliminary data demonstrates that EGD2 dosage affects telomere length homeostasis, albeit modestly. Overexpression of EGD2 slightly lengthens telomeres, while egd2- strains have slightly shortened telomeres. Whether the alteration in telomere length is a direct effect of Egd2 function at the telomere is an important, but unresolved question.

SYNTHESIS, CHARACTERIZATION AND PSEUDO-CAPACITIVE PERFORMANCE OF MANGANESE OXIDE NANOSTRUCTURES

Chung-Ying Tsai — Wed, 06 Mar 2013 07:26:48 PST

In this research, manganese oxide based nanoparticles were synthesized by sol-gel process. Methanol, ethanol, and propanol were used as alternative solvents during sol-gel process with manganese acetate as precursor for the preparation of pristine manganese oxide. Hybrid manganese oxide modified by additions of carbon nanotubes was further prepared. The effects of different solutions and heat treatment temperatures on the morphology, physical characteristics, and electrochemical properties of the manganese oxide based materials were investigated. Particle size of pristine manganese oxide samples prepared from methanol, ethanol, and propanol were compared by SEM and TEM image analysis. Smallest particle size was observed for manganese oxide prepared from propanol, with diameters range from 16 nm to 50nm. XRD results showed that the as-prepared manganese oxide based samples treated at calcination temperature of 300ºC and above were composed of Mn₂O₃ as dominant phase, with Mn₃O₄ as minor phase. Specific capacitance of manganese oxide prepared from methanol, ethanol, and propanol at scan rate of 10 mV/s measured using two electrode systems were 88.3, 66.0, and 104.8 F/g, respectively and that for the hybrid sample was 140.5 F/g. Results from electrochemical impedance spectroscopy (EIS) also showed superior electrochemical properties of the hybrid sample over pristine manganese oxide samples. It is evident that the addition of carbon nanotubes not only improved the specific capacitance but also the overall electrochemical properties of the manganese oxide supercapacitor.

ERBIUM DOPED CERAMIC NANOFIBER SYNTHESIS FOR THERMOPHOTOVOLTAIC SELECTIVE EMITTER APPLICATIONS

George Sebastian Trifon — Wed, 06 Mar 2013 07:26:46 PST

This thesis explored the development of isothermal selective emitters for harvesting thermal energy to be used in conjunction with photovoltaic cells. The selective emitters were Erbium doped Titania nanofibers and Erbium and Yttrium doped Titania nanofibers that may be used with a Gallium Antimonide photovoltaic cell. The ultimate aim of this research was to develop Erbium doped Yttrium Titanate nanofibers. This research is of importance in recovering heat from a number of resources including power plant boilers. The thermal energy lost in the boilers can be as high as 20% of the input fuel energy and a recovery of this energy would boost the thermal performance of the power plants. It has been observed that the temperatures of the flue gas reaching the heat recovery region may be higher than 1600K and the radiation and convective losses in the burner occurs at even higher temperatures. Thermophotovoltaics (TPV) offer a solution in terms of converting the thermal energy to electricity without any moving parts. The efficiencies of conventional TPVs are very small (10 - 20%) and thus not a solution as the primary electric generator. However, in the field of the harvesting of waste energy, TPVs have tremendous potential. In order to improve efficiencies, Erbia (which can absorb thermal energy and convert it to electromagnetic radiation with a narrow wavelength spectrum with mean wavelength of 1500nm) can be used as a selective emitter with GaSb PV cells (which have its maximum efficiency in the same wavelength range) as the collector. In order to further improve its performance, the Erbia was proposed to be supported by Titania, which is transparent to IR in this range. However, past research has shown that the Erbia doped Titania nanofibers essentially have Erbium in the form of pyrochlore Erbium Titanate. Thus the research focused on a way to synthesize ErxY2-xTi2O7 pyrochlore structure to act as the selective emitter. The self-supporting composite was designed to be nanostructured to ensure isothermal operation and a high surface to volume ratio to minimize re-adsorption and to have a compact design. The nanofiber emitters were prepared by electrospinning. This thesis demonstrated a synthesis procedure of optically selective nano-composites using electrospinning.