Summer 2011 Research Projects
Scholar: James Bailey
Mentor: Todd Easton, Ph.D.
An Intermediate Perfect Graph Theorem
A graph is perfect if for every induced subgraph H, the chromatic number of H is equal to the size of the largest clique in H. The strong perfect graph theorem states that a graph is perfect if and only if it contains no odd holes or odd anti-holes. To date there does not exist an elegant and easily verifiable proof of this theorem. This paper shows that a graph is perfect if it contains no odd holes and any odd cycles of length five have at least two chords.
Scholar: Theresa Barke
Mentor: Lynn Hancock, Ph.D.
The Role of Lgt and LspA in Lipoprotein Modification and its Impact on Heme Regulation in Enterococcus faecalis
Lipid modified peripheral membrane proteins undergo a series of enzymatic modifications in their journey from pre-prolipoproteins to mature lipoproteins. Acylation of hydrophilic proteins by the enzyme, lipoprotein diacylglyceryl transferase (Lgt), facilitates its embedding within the hydrophobic lipid membrane. Lipoprotein signal peptidase (Lsp) is responsible for cleaving the signal sequence from the embedded prolipoprotein resulting in a mature lipoprotein. The cleaved signal sequence undergoes further processing by other proteases resulting in small linear peptides known as sex pheromones which are excreted by plasmid-free strains of E. faecalis and facilitate plasmid transfer with conjugative plasmid carrying donor strains. It was hypothesized that the deletion of lgt and lsp would affect the downstream processing and production of sex pheromones leading to a decrease in transconjugation efficiency between donor and recipient strains. Lgt and lsp isogenic mutants were created in E. faecalis FA2-2 using markerless gene deletion techniques. Transconjugation efficiency was determined using the isogenic lgt and lsp mutants as recipient strains and three OG1SSp strains carrying the plasmids, pCF10, pAM714, and pAM378, as donor cells. Successful conjugal transfer of plasmids was determined by the acquisition of antibiotic resistance as a marker. It was determined that while the deletion of lgt in the recipient FA2-2 strain showed little impact on the ability of E. faecalis to successfully transfer plasmids, the deletion of lsp resulted in a significantly decreased number of plasmid transfer events.
Scholar: Donte Bernard
Mentor: Donald Saucier, Ph.D.
Discrimination in Interracial Group Helping Situations Related to Allocation of Funds
Discrimination often occurs in interracial helping situations particularly when not helping can be justified using other situational factors (e.g., the justification-suppression model of prejudice.) Utilizing the justification-suppression model of prejudice in a helping paradigm, we conducted a study to examine if individuals who were higher in racism would be less likely to allocate funds to organizations that help minority students. White participants completed a racism measure and later were asked to allocate a large sum of money across a variety of student organizations, some of which helped minority students. Results revealed that participants allocated less money to the organization that benefited Black students. Participants' racism scores, however, were not correlated with the amount of money that was allocated to each group. These results add to the literature on discrimination in helping situations and suggest that high levels of financial cost may serve as a justification factor in interracial helping situations.
Scholar: Johanna Diaz
Mentor: Deon Van der Merwe, Ph.D.
Roadside Plants as Metal Contaminant Indicators
The use of plants to indicate environmental contaminants is a potential alternative to the use of chemical or physical tests. Typha spp., more commonly known as cattails, are of interest due to their tolerance of heavy metals, and their abundance in areas that are likely to become contaminated with elements that are washed from road surfaces, such as roadside ditches where runoff water accumulates and stagnates. To test the hypothesis that cattail stands grow in roadside areas that are more contaminated (as suggested by higher element concentrations) than other roadside areas, surface soil of 15 roadside cattail stands were compared to 43 control surface soil samples from roadsides without cattail stands. Samples were collected from roadside ditches next to paved roadways in Riley and Pottawatomie Counties, Kansas, USA. After nitric acid extraction, soil samples were analyzed for beryllium, magnesium, aluminum, potassium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, silver, cadmium, antimony, barium, thallium, and lead, using inductively coupled plasma mass spectrometry. Also, total organic contents were estimated gravimetrically following sample ashing. Four element concentrations differed significantly between cattail and control soils. Vanadium and magnesium were higher in cattail soil versus control soil. Barium and silver concentrations were higher in control soils. All other tested elements, and total organic contents, were not significantly different between cattail and control soil samples. The results did not support the hypothesis that cattails indicate roadside areas of increased elemental contaminant concentrations.
Scholar: Kelsie Doty
Mentor: Sherry Haar, Ph.D.
Exploration of Natural Dyes from Osage orange (Maclura pomifera), Walnut (Juglans nigra)
and Eastern Red Cedar (Juniperus virginiana) Bark on Wool and Alpaca Yarns
This research examined the color effects of Osage orange (Maclura pomifera), Walnut (Juglans nigra) and Eastern Red Cedar (Juniperus virginiana) bark on mordanted and nonmordanted protein yarns dyed using a solar method for dye extraction. Three different yarns, 100% Alpaca (3-ply), 100% Merino wool (4-ply), and 96% wool with 4% nylon (boucle) were used. Half of the samples were scoured and premordanted with a formula of potassium aluminum sulfate (12% WOF) and cream of tartar (6% WOF). The other portion of yarn was scoured and left unmordanted. The solar dye extraction method consisted of each species of bark, calculated at a 3:1 ratio of bark to fiber, being placed in separate stainless steel pots of water and placed outdoors for one week. The bark was then strained and the dye liquor distributed amongst the wetted yarns and placed outdoors for two weeks. Color differences of the dyed yarns were assessed using American Association of Textile Chemists and Colorists Visual Assessment of Color Difference of Textiles descriptors. Yarns premordanted with potassium aluminum sulfate were consistently warmer, brighter and had a more yellow hue to the overall appearance. The 100% Merino Wool 4-ply obtained the darkest color most likely due to the loosely twisted yarn structure and fiber content. Yarns dyed with Walnut bark produced the darkest colors, possibly due to a higher concentration of tannic acid occurring in the walnut bark or the darker pigmentation leached during extraction. Future research will examine colorfastness properties of walnut bark, leaves, and hulls between mordanted and nonmordanted fibers.
Scholar: Lisa Hillstock
Mentor: Nora Bello, Ph.D.
A Case Study of Patient Flow and Contact at a Local, Private Veterinary Practice
The purpose of this research was to discover the range and scope of patients and cases that a typical private veterinary practice would treat within a specific time range. The information was gathered during a three month volunteering experience and focused primarily on patients' demographic information, the types of appointments, and diagnoses and treatments of the patients. Information on clinical practices, procedures, and issues was also gathered. 300 patients and 334 appointments were observed. Majority of the patients were dogs. There was a 1:1 ratio between male and female patients. 171 patients were spayed/neutered vs. 123 who weren't. 90 patients were mixed breeds, and 210 were pure breeds. The majority of appointments were surgeries (47) and illnesses (40) the fewest being work-ups (7) and injuries (9). In addition to numerical data, other clinical issues were observed regarding age requirements, breed restrictions, financial contracts, rabies laws, and doctor-owner communication.
Scholar: William Jernigan
Mentor: David Gustafson, Ph.D.
Object Recognition by Shape
The field of computer vision depends on object recognition in its various applications. In this research, we wrote code that tries to identify objects by the characteristic shape of the object. We made the decision to identify one object, a bottle, in images. First, edge detection is used to find the outline of the possible object. Then, the code follows the detected edge to find the outline of the object. A descriptor of the shape of the outline is constructed and compared with defined descriptors to determine if a bottle is present. The code returns whether or not a bottle is identified, as well as an image of the edge detection.
During testing, we used images with increasing complexity and documented the performance of the code. The test images varied in multiple ways, including orientation of the bottle. The work in this project may be expanded in further work to other types of objects.
Scholar: Emily Mollohan
Mentor: Timothy Rozell, Ph.D.
Exercise Physiology and Production Characteristics of Cattle
Leaving cattle with little to no human contact in a feedlot setting has been a common practice in the livestock industry. However, required minimal handling could possibly lead to more stress when they are handled for shipping and slaughter, which can cause poor quality beef. Four groups (Sloth, Decathalete, Early, and Late) of steers were used to evaluate whether exercise provides an appropriate stimulus for changes in animals' stress response by controlling the amount of human contact for cattle over a 20 week period. This subset project compares only the Sloth and Early group of steers. It compares blood gas levels to show whether exposure to human contact on a regular basis will affect the amount of stress the cattle undergo during times of processing. This study is ongoing, and blood gas results will be collected and analyzed.
Scholar: Graciela Orozco
Mentors: Stacy Hutchinson, Ph.D. & Jesse Nippert, Ph.D.
Temperature Impacts on Native Tallgrass Prairie Water Usage
Understanding water use of the native tallgrass prairie will be critical for predicting future responses of the tallgrass prairie to climatic changes (i.e. temperature, precipitation, etc). To better understand plant water use in response to climate, a study was conducted using climatic data (temperature), reference evapotranspiration (ETr), daily calculated evapotranspiration (ETo), and soil moisture from 2001-2010 from the irrigation transects on Konza Prairie in Kansas, USA. In order to understand temperature impacts on water use, a water use coefficient was calculated using the relationship between reference ET, calculated using the modified Penman-Monteith equation, and the actual plant water use: ETc = ETx Kc x K, where Kc is the plant water use coefficient, and Ksm is the soil moisture coefficient. In fully watered sites, the plant water use coefficient is based on the relationship of ETc/ETr because K = 1.0 due to ample water. A similar method was used for unwatered sites to calculate Kc. Results from imposing the water use coefficients of fully watered and unwatered sites upon one another indicated varying responses to climate, but especially temperature. Over the growing season (June 1 to September 30), fluctuations in plant water use were in response to precipitation events and temperature. Early season precipitation (~June 1 to July 9) is the initial driver of plant water use; however, water use later in the growing season (~July 15 to August 19) is primarily a factor of temperature.
Scholar: Lee Rathbun
Mentor: Amanda Murdie, Ph.D.
Trading Rights: The Impact of Economic Sectors on States' Physical Integrity and Workers' Rights Observance
What impact do trade exports have on human rights performance? Does the specific nature of the exports matter? Drawing on research from DeMeritt and Young (2010), in which it is found that there is a positive relationship between oil exportation and an increase in physical integrity rights violations, this article attempts to explain the correlation between the main export of a state and the level of physical integrity rights violations. By definition, physical integrity rights are the rights not to be tortured, summarily executed, disappeared, or imprisoned for political beliefs. The scores of these variables can be summed to form a statically valid cumulative scale (Cingranelli and Richards, 2010). This research seeks to reveal the specific economic sectors the lead to a higher occurrence of such violations. I test my hypotheses using a cross national database indicating each state's main export as well as their reliance on human capital and the extent of physical integrity right violations.
Scholar: Jessica Reyes
Mentors: Kara Northway, Ph.D. & Deborah Murray, M.A.
Developing the "Rhetorical Context": Understanding Faculty Attitudes towards Writing and Writing Instruction at Kansas State University
My research uses a survey to identify congruencies between, on the one hand, K-State faculty members' approaches to their own and their students' writing and, on the other hand, writing practices promoted in the writing center. The results show that while faculty members engage in revision and collaborative practices in their own writing, they do not always fully support the development of these practices in their students. Because of this, tutors should continue to emphasize the importance of writing to students' academic and professional success and continue to encourage revision and collaborative practices as tools for students to improve their writing. Furthermore, the survey provides quantifiable data demonstrating the need for increased and expanded tutoring services on campus.
Scholar: John Sibbitt
Mentors: Brian Lindshield, Ph.D.
Determining Effective Culturing Method for PC346-C Cell Line for In-Vitro Study of Prostate Cancer
Background: Commonly, aggressive and fatal prostate carcinomas evolve from PC's initial mild nature, making it the second leading cause of male cancer deaths in America. Therefore, a cell line resembling early stage PC has importance in clinically relevant in-vitro research. The majority of diagnosed PC's are initially mild in nature, thus understanding PC's progression to more advanced stages can prove pivotal in prevention of deadly carcinomas. The PC346-C cell line is unique, because it maintains early stage PC characteristics, unlike the majority of PC cell lines, which are derived from and model advanced stages of the disease. However, PC cells are among the most difficult to sustain in culture. To help, we documented potential pitfalls of culturing viability and possible solutions.
Approach/Results: PC346-C cells were obtained from the Erasmus Medical Center, located in Rotterdam, Netherlands. Cells were taken up from cryopreservation and seeded into Primiria T-25 flasks. Flasks contained 4 mL of DMEM-F12 base media plus 17 different complex additives to encourage attachment and growth. Flasks were incubated at 37 Celsius in a 5% C02 atmosphere and media were changed every 3 days. If confluence was reached, cells were sub-cultured via trypsinization at 1:3 split ratios. Attachment periods, percentages of confluence, doubling times, and general cell health were documented to ascertain the culture's viability. The cells displayed healthy morphology; however, proliferation rates were sub-optimal.
Conclusions: Human error in the preparation of the complex media likely contributed to the poor growth observed. After identifying several growth inhibiting problems, we boosted proliferation rates. However, proliferation was still sub-optimal. Further study is needed to determine the reason for these poor growth rates. The difficulty of culturing early stage prostate cancer in-vitro models was verified.
Scholar: Gabrielle Sims
Mentors: Timothy Musch, Ph.D. & David Poole, Ph.D.
The Role of n-NOS Inhibition in Cardiovascular Control
Neuronal nitric oxide synthase (nNOS) mediates vascular control. When nNOS is blocked at rest using S-methyl-L-thiocitrulline (SMTC), blood flow and vascular conductance to hind- limb muscles decreases and mean arterial pressure increases simultaneously (MAP, Copp et al. J Physiol. 588: 1321-31, 2010). This investigation tested the hypothesis that nNOS blockade with SMTC would increase lumbar sympathetic nerve discharge (SND) in parallel with an increased MAP in baroreceptor-denervated rats consistent with centrally-mediated SMTC effects. However, contrary to this hypothesis, after SMTC infusion lumbar SND did not increase (P>0.05) whereas MAP did (+40+8.3%, P<0.05) and there was no correlation between these variables. In contrast, renal SND (+17.6+6.5%, P<0.05) correlated significantly with MAP (r=0.66, P<0.001). These data suggest that SMTC-induced resting skeletal muscle blood flow is mediated principally by peripheral (i.e., muscle) rather than central (via SND) nNOS blockade. Furthermore, renal sympathetic vasoconstriction likely contributes to the elevated MAP seen with nNOS blockade.