2007 Senior Presentations in the Sciences
Friday, March 16, 2007
Dominican Hall Auditorium
Schedule of Presenters
10:00-10:30 a.m. Grant Hesson
EFFECTS OF ANTHRANILIC ACID AND CYSTEINE ON THE SEED GERMINATION OF BRASSICA RAPA AND BRASSICA OLERACEA
By comparing different concentrations of anthranilic acid and cycsteine, precursors to camalexin, it was discovered that both have a significant effect on broccoli (Brassica oleracea) and turnip (Brassica rapa) seed germination. These effects could be important to the seed industry in trying to maximize seed vigor, which increases seed productivity.
10:30-11:00 a.m. Koral Herzog
TETING THE EFFECTIVENESS OF REHABILITATION METHODS OF WILDLIFE RESCUE AND REHABILITATION IN KENDALIA, TEXAS
While interning at Wildlife Rescue and Rehabilitation, I was performing methods of rehabilitation for wildlife. I tested the effectiveness of these methods by comparing the ages or weights to the outcomes of raccoons, opossums, and white-winged doves.
11:00-11:30 a.m. Erin Mannor
DETERMINATION OF THE EFFECTIVENESS OF FOUR COMMON FLY REPELLANTS IN DOMESTIC HORSES (Equis Caballus)
Twenty-seven horses were used to compare the effectiveness of four common fly repellants. Effectiveness of the repellants was determined by comparing the observed number of flies landing on the legs of horses during five minute intervals prior to and after application of a repellant. Three commercially available repellants were compared to a standard solution containing equal parts distilled water and white vinegar. The commercially available repellants used were: Farnam Bronco® (0.10% permethrin, 0.05% pyrethrins, and 0.50% piperonyl butoxide technical), Farnam Nature’s Defense® (0.35% citronella oil, 0.15% clove oil, 0.25% mint oil, 0.25% thyme oil, and 3.33% sodium lauryl sulfate), and Absorbine® Super Shield Green™ (citronella oil, eucalyptus, lavender, pennyroyal, pine needle, and witch hazel). The repellants were determined to be effective, showing a significant difference in the number of observed flies before and after application of a repellant (p<0.05). Additionally, significant differences were detected between the four fly repellants (p<0.05).
11:30-Noon Brad Moran
THE EFFECTS OF CAMALEXIN INTERMEDIATES, CYSTEINE AND ANTHRANILIC ACID, ON THE SEED GERMINATION PATTERNS OF AVENA SATIVA AND POA PRATENSIS
Camalexin, a known phytoalexin found in plants such as Aribodopsis thaliana, has many chemical components. Two of the components of camalexin are anthranilic acid and cysteine. After using both anthranilic acid and cysteine in different concentrations on Kentucky Blue Grass (Poa pratensis) and Sweet Oat (Avena sativa) seeds, a significant difference in germination was observed.
1:30-2:00 p.m. Erika Wolcott
EFFECTIVENESS AND TOLERABILITY OF 6.0% HYDROGEN PEROXIDE TOOTH WHITENING STRIPS
Hydrogen peroxide has been used in dentistry for more than 70 years to bleach teeth, and in recent years the regular application of hydrogen peroxide has become more widely used as part of dental hygiene. Proctor & Gamble of Cincinnati has developed a polyethylene strip which has been coated with a .20mm gel layer of 6 percent concentrated hydrogen peroxide (Crest Whitestrips Classic™). A two week trial was conducted to assess the effectiveness and tolerability of the twice-daily strips. Changes between the baseline tooth shade and the final shade were measured using the Vita 3-D Master Shade Guide (Vident, Germany). Relative to the baseline shade, the group of participants exhibited significant (P=0.00) improvement in shade color. Use of the 6 percent hydrogen peroxide gel strips resulted in low levels of sensitivity and 100% of the subjects observed an improvement in final tooth shade (average shade change of 7.06 units). The use of Crest Whitestrips Classic™ (Procter & Gamble) offers a useful approach for at-home vital bleaching.
2:00-2:30 p.m. Robert Nydza
THE USE OF WHOLE EMBRYO CULTURE AND A CHEMICAL INHIBITOR OF HEDGEHOG SIGNALING AS A TRACTABLE MODEL OF HOLOPROSENCEPHALY
Cyclopamine causes malformations in vertebrates consistent with holoprosencephaly (HPE), the most common forebrain defect in the human population, by inhibiting the Hedgehog signaling network. Genetic screening found mutations in Shh and Gli2 in 7% of human probands affected with HPE. However, each involved single allele loss-of-function (LOF) mutations where some carries were clinically normal and some were severely affected, suggesting other genetic or environmental factors may be involved. Previously, the use of mouse whole embryo culture (WEC) along with cyclopamine was described as a model of HPE. Here, we set out to establish the use of WEC to examine the interaction of both chemical and genetic perturbations in Hh signaling. We successfully cultured mouse embryos in vitro from E8.5 to E10.5 with high fidelity compared to in vivo development. Consistent with the previous reports, we found that cyclopamine exposure caused a dose-dependent reduction in the growth of the nasal placode, a phenotype consistent with mild HPE. Moving forward, using null mouse models which mimic LOF mutations seen in human HPE, we will be able to determine whether single allele mutations in Shh or Gli2 alter sensitivity to chemically-induced HPE.
2:30-3:00 p.m. Lisa Gramm
FUMED SILICA VS. COLLOIDAL SILICA
Fumed and colloidal silica slurries are widely used in the CMP industry (Chemical Mechanical Polishing). These slurries are used by microchip manufacturers to polish their wafers between each layer of the device. In order to obtain a high efficiency slurry, it must have the correct removal rates for the end users microchip, and must not cause many defects on those devices. For this reason, colloidal silica is very popular since it is a softer particle than fumed silica. The methods to make the two slurries are vastly different. Fumed silica slurry is made by using a high shear mixer to force the hydrophobic silica into water with the help of a wetting agent. The colloidal silica is actually grown by adding silicic acid to an alkaline mixture at 100C. This reaction is carried out at the high temperature and later cooled for use. Ultimately both groups have almost identical amounts of each chemical added, SiO2 , water, corrosion inhibitor, acid and oxidizer. At Planar Solutions, fumed silica has been around for 8 years and will be used as the control, colloidal silica is new and will be checked against measurable difference between the two groups by using standard CMP testing.