The 8th
Annual
NC
Undergraduate
Summer Research Symposium
HHMI Reaching Incoming
Students Enrichment (RISE) abstracts
Abstracts are listed in
alphabetical order by the last name of the corresponding author.
|
Beane,
Jennifer B. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
CALS |
|
Department(s): |
Food Science |
|
Research Mentor(s): |
Sophia Kathoriou/Food Science Vikrant Dutta/Microbiology |
|
Title of Presentation: |
Does the Ciliated Protozoan Tetrahymena Influence the Survival of the
Food-borne Pathogen Listeria
monocytogenes? |
Listeria
monocytogenes is a food-borne facultative intracellular
pathogen that can cause fatal disease in humans and animals; thus it is
important to identify its reservoirs and assess its survival in numerous
environments. Few studies have investigated the interaction between L. monocytogenes and
protozoa. The objective of this study
was to investigate the ability of this pathogen to survive in the ciliated
protozoan Tetrahymena (THM). A 72
hour trial was conducted to monitor the survival of L. monocytogenes in THM by using three
pathogenic strains of L. monocytogenes (4b1, H7550, and F2365)
representing major epidemic clones of the bacterium and one non-pathogenic
strain of Listeria innocua (CLIP-11262) inoculated in THM. During the
first day of each trial, bacteria were washed in Osterhout’s Solution, diluted
10,000fold, and then inoculated into 100 microliters of THM. After 24, 48, and
72 hours, colony forming units were monitored by cell plating. At 72 hours,
gentamycin treatment was given to each of the different strains to kill
extracellular bacteria. After thirty minutes, the THM suspension was
centrifuged and treated with Triton-X to release the intracellular bacteria
which were then enumerated on agar media.
The findings suggested that L. monocytogenes' survival was increased in
the presence of THM because L.
monocytogenes cultures without THM
significantly declined in number. Pathogenic L. monocytogenes survived better in the presence of THM than
nonpathogenic L. innocua . More research is currently being
conducted to further characterize the interaction between L. monocytogenes and THM.
|
Bulfin,
Mary P. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
CALS |
|
Department(s): |
Animal Science |
|
Research Mentor(s): |
Vivek Fellner/Animal Science Sarah Jo McLeod/Animal Science |
|
Title of Presentation: |
The Gas Mask: Plants’
Secret Alliance with Methane |
Methane (CH4) is 20 times more potent than
CO2 as a greenhouse gas.
Primary identified sources of CH4 do not include recent
evidence of CH4 derived from thriving plants. We conducted this study to monitor methane gas
emissions from 4 different species of plants: Basil “Thai
Magic” (Ocimum
basilcum), Boris Avens (Geum
coccineum “Borisii”), Max Q. Fescue (Neotyphodium
coenophialum), and Coastal Bermuda Grass (Cynodon dactylon). Plants
were grown in glass vessels placed near a window that provided natural sunlight
for 4 to 5 hours daily. Compressed air
was circulated through the vessels at 10 mL/min. Prior to the addition of the plants, gas
samples were taken from the vessels at several time intervals for the first 36
h to obtain baseline samples.
Thereafter, gas samples were obtained twice daily for 7 d. At the end of d 7, air flow into the vessels
was terminated, and gas samples were taken for an additional 4 d. On d 11, all plants were clipped and CH4
was monitored for an additional 4 d with clippings remaining in the
vessels. Room air composition and
temperature were monitored daily throughout the experiment. Gas samples were analyzed for CH4,
N2, O2, and CO2 using gas chromatography. Data were analyzed as a randomized block
design using Proc GLM procedure of SAS.
Percent composition of baseline room air was 79.0, 20.9, and 0.1 for N2,
O2 and CO2, respectively, which is similar to reported
atmospheric gas concentrations. Average
baseline CH4 values were 0.51 micrograms. Irrespective of plant species, CH4
concentration increased (p < 0.12)
to an average of 0.56 micrograms. With
an increase in temperature from 23oC to 35 o C, CH4
increased by 38% and CO2 decreased by 58%. Clipping plants did not increase CH4.
Our results indicate that growing plants should be considered when accounting
for global methane emissions.
|
Childress,
Ashley E. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
CALS |
|
Department(s): |
Plant Biology |
|
Research Mentor(s): |
Marc T. J. Johnson/Plant Biology Rose Grinnan/Plant Biology |
|
Title of Presentation: |
The Effects of Drought, Temperature, and Herbivory
on Soybeans |
The Earth is experiencing a
vast climate shift that is predicted to lead to increased temperatures and
drought, and theory suggests that these changes may also cause more frequent
outbreaks of insect pests. These changes in the abiotic and biotic environment
can have negative impacts on both natural and managed ecosystems. We sought to
test the combined effects of temperature, drought, and herbivory on the
performance of the globally important crop soybean (Glycine max). This was
achieved by conducting three fully factorial experiments in growth chambers and
a greenhouse. We tested a total of 614 plants: 24 in the growth chamber, 80 in
the first greenhouse experiment, and 510 in the second greenhouse experiment.
In the growth chamber, higher temperatures caused plants to grow faster and
gain more biomass. Once the drought was imposed, a decline in performance was
obvious. The plants at the higher temperature wilted significantly faster, and
therefore died at a higher rate. In the first greenhouse experiment, the
drought period ranged from 3–5 days
based on the percent of wilting. After this period of time all of the drought
plants were able to respond to water and were revived. We then introduced
caterpillars to the plants. The caterpillars remained on the plants until a
third of each plant had been eaten. In the second greenhouse experiment we used
51 different genotypes of Glycine max
to test whether there is genetic variation in response
drought and resistance to insects, and how these traits are related to plant
performance. By examining the ecological effects of climate change and the
response of many soybean genotypes to these changes, we will be able to help
the agriculture industry find ways to mitigate negative impacts of future
environmental change.
|
Jiang, Wendi |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
CALS |
|
Department(s): |
Food Science |
|
Research Mentor(s): |
Sophia Kathariou/Food Science Robin Siletzky/Food Science |
|
Title of Presentation: |
Prevalence and Clone
Stability in Multidrug Resistant Campylobacter
coli from Turkeys in North Carolina |
Campylobacter is a food borne bacterial pathogen that can cause
severe intestinal complications through contaminated foods. C. coli is frequently found to be Multidrug resistant
(MDR), defined as harboring resistance to all of the following antibiotics:
tetracycline, streptomycin, erythromycin, kanamycin, and
ciprofloxacin/nalidixic acid. C. coli
frequently colonizes poultry and swine and is responsible for about 15% of all Campylobacter infections. Therefore, the high prevalence of MDR strains
poses a threat to public health. A study
conducted from 2002 to 2007 isolated many MDR strains from turkeys grown conventionally
across North Carolina. In this follow up
study, our objective was determine prevalence of MDR strains in recently
collected samples (summer 2009) and to determine strain subtypes relative to
those found in the previous study. The
majority (88 %) of the samples were colonized with Campylobacter. MDR isolates
were found among 40 % of all tested C.
coli. Using pulsed-field gel
electrophoresis (PFGE) and fla typing, we were able to determine that several of the
isolates collected in the current study were either similar or identical to
strains found in the previous study.
Such findings would suggest stable MDR clonal groups in the turkey
industry.
|
Klumpe, Heidi E. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
Engineering and Technology |
|
Department(s): |
Mechanical and Aerospace
Engineering |
|
Research Mentor(s): |
Scott Ferguson/Mechanical and Aerospace Engineering |
|
Title of Presentation: |
Avoiding Sidewalk Omelets:
A Multi-objective Approach to the Egg-drop Competition |
The egg-drop has baffled benign engineering students
for years. The usual approach, a collection of disparate objects haphazardly
packaged in cardboard, belies the true complexity of this dynamic loading
problem. Conversely, the application of the design process provides a reliable
framework which generates optimal, clever, and generally more successful
designs. This method of “glorified decision-making” helps engineers clarify the
task at hand, plan a principle solution, specify a layout, gather information,
and identify trade-offs. Essentially, this information is what the engineer
needs to make decisions about what materials or mechanisms to use in the final
design. These decisions are based on the
results of experimentation and how highly the utility, or gain, of each
component is ranked. In terms of the egg-drop, each potential solution has a
mass, cost, and a property of force absorption, which must meet the required
functionality. A dual-nature experiment,
using both an accelerometer and raw chicken eggs, was used to analyze the
force-absorbing properties of various household materials at different
heights. Additionally, the construction
of a guide-wire system ensured accurate and repeatable drops. The performance
criteria considered present a multi-objective optimization problem whose
solution dictates the look of the final design. Every design can be different
as engineers make different decisions according to their specified preferences,
which in turn affect the properties of the design
|
Manzer,
Oliver R. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
CALS |
|
Department(s): |
Genetics |
|
Research Mentor(s): |
Laura Reed/Genetics |
|
Title of Presentation: |
Natural Metabolic Weight
Gain of Drosophila |
Drosophila melanogaster are often raised in homogeneous
lines of continual inbreeding in labs for experimentation. When a growth
experiment was carried out on different sugar concentrations on food, there was
an anomaly at a 4% concentration where the weight gain was the lowest. Our
hypothesis behind such an anomaly was due to the multiple generations before
the test subjects had all been raised on a 4% sugar diet and thus the offspring
had been selected for an optimal weight on a 4% diet. Due to these results a
parallel experiment was conceived to test this conclusion by checking the
weight gain on a culture of wild flies to see if the results were similar to
those in the previous experiment if so then the culturing in lab environments
would have little effect on genetics of a population in relation to a specified
diet. The experiment was carried out by determining the species of wild flies
caught in traps by isolating females then identifying by the male
offspring. Once the correct species was
identified the 1st generation offspring were place in laying chambers of all D.
melanogaster 1st generations collected to provide a diverse population for
breeding to prevent inbreeding and replicate a wild population. The 1st instar
larvae were then placed in foods of the specified sugar concentrations of 0-8%,
along with a set of five cultured lines to act as a control and replicate the
previous experiment, then allowed to grow to the mature pupae stage. Upon reaching the mature pupae stage they
were collected to be weighed once all pupae had been collected. Due to the maturing rate of D. melanogaster,
the results for the wild pupae are yet to be determined as they are still
maturing.
|
Miller, John T. N. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
Engineering and Technology |
|
Department(s): |
Biomedical Engineering |
|
Research Mentor(s): |
Glenn M. Walker/Biomedical
Engineering Elizabeth G.
Loboa/Biomedical Engineering Adisri (Audrey)
Charoenpanich/Biomedical Engineering Amy McPherson/Biomedical Engineering |
|
Title of Presentation: |
Recreating the Human
Auditory Ossicles through Tissue Engineering |
Our goal is to recreate a representation of the human
auditory ossicles by combining micromolding techniques with osteogenic stem
cell stimulation. Polydimethylsiloxane (PDMS) molds, typically utilized for
bio-microelectromechanical systems, are non-toxic to cells and therefore an
ideal material. The malleus, incus, and
stapes were drawn on the computer to scale. Because of the natural shrinking
tendencies of cell-seeded collagen (as much as 80%), the original dimensions
were scaled in increments of 20% until 200%, resulting in six different sets.
The drawings were used to create photomasks, which were then employed in making
PDMS molds. After the PDMS molds were produced in triplicates, stem cell-seeded
collagen was placed in each and given complete growth media (CGM). Following 24
hours in the incubator, the CGM was replaced with osteogenic media (OM) in
order to stimulate the stem cells down the osteogenic path and become bone. Our
objectives are to observe the reduction in size of each set to determine the
closest match to actual ossicle size and to develop or improve on a method to
preserve the shape of the cell-seeded collagen and keep it from resisting its
mold. The ability to control the growth and development of cell-seeded collagen
is important for medical applications of tissue engineering in the future.
|
Monian,
Brinda |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
Engineering and Technology |
|
Department(s): |
Mechanical and Aerospace
Engineering |
|
Research Mentor(s): |
Stefan T. Seelecke/Mechanical Engineering Alexander York/Mechanical Engineering |
|
Title of Presentation: |
Optimization of a Mock Blood Flow Circuit for
In-Situ Monitoring of Stent Migration and Deformation |
Abdominal aortic aneurysm (AAA) is one of the leading
causes of death in the United States. To prevent aneurysm rupture, a stent is
typically inserted into the aneurysm; however, in some patients, the stent is
subject to migration and deformation. The aim of our study is to gain an
understanding of the causes of stent failure and thereby assist surgeons in
recommending different AAA stents based on patients’ aortic geometry. Our
vision is that in the future, stents will be custom-built according to the patient’s
specific morphology. An artificial blood
flow system was developed to observe the movement of a stent inside a synthetic
aneurysm over time. The system consists of a linear actuator pump (simulating a
human heart), a reservoir, a synthetic aneurytic aorta
with a pressure sensor, and medical tubing between the system components. In this study, an aqueous glycerin solution
was created to mimic the properties of blood. Several concentrations were mixed
and tested using a rheometer to determine the solution that best simulated the
density and viscosity of whole blood at body temperature. The blood flow system
was run with the optimum aqueous glycerin solution, and the operating
parameters of the pump were adjusted to achieve the aortic pressure and blood
flow rate in the human circulatory system. The pump settings adjusted included
the displacement per stroke and the piston speed and acceleration. In addition,
the reservoir height was varied as well as the system impedance using an
adjustable ball valve. We observed that the pressure profile was qualitatively
reproduced but did not exactly match the desired pressure waveforms of the
human aorta. Solutions to obtain a better pressure profile for a variety of
physiological conditions such as normal blood pressure, hypertension and
differing rest/activity frequencies are proposed.
|
Mitchell,
Shaneice R. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
CALS |
|
Department(s): |
Biology |
|
Research Mentor(s): |
Heather B. Patisaul/Biology |
|
Title of Presentation: |
Do Kisspeptin Neurons in
the Arcuate Synapse on Gonadotropin Releasing Hormone Neurons? |
Within the brain, lie two populations of neurons that
control estrogen production in the body by releasing a peptide called
kisspeptin. This peptide activates the production of gonadotropin releasing
hormone (GnRH) in the brain that, in turn, activates the secretion of
luteinizing hormone (LH). LH then enters the bloodstream to stimulate the
secretion of estrogen from the ovaries. Estrogen levels in females are
maintained by a negative feedback loop which shuts down the production of GnRH.
However, at ovulation estrogen levels surges and the negative feedback loop is
turned off. We believe one group of kisspeptin neurons, which lie in the
arcuate nucleus, controls the surge of estrogen levels during ovulation through
synapse with GnRH neurons. To test our hypothesis we completed a combination of
track tracing and immunohistochemistry to map the neuroendocrine circuits and
determine if the kisspeptin neurons in the arcuate nucleus synapse with GnRH
neurons. To begin labeling the brain circuit, we extracted adult rat brains (3
males, 2 females). We then implanted DiI into the arcuate nucleus and incubated
them for eight weeks to label all of the neuronal fibers projecting from the
arcuate. Next we used immunohistochemistry to label the neuronal fibers which
produce kisspeptin to see if the kisspeptin neurons synapse with GnRH neurons.
We imaged the brains and observed that there are neurons in the arcuate which
appear to synapse with GnRH neurons in the brain. We also observed that there
are kisspeptin fibers present in the vicinity of GnRH neurons, but they did not
appear to come from the arcuate nucleus. This shows that kisspeptin neurons
synapse with GnRH neurons; however the kisspeptin fibers do not originate from
the arcuate nucleus. In the future further analysis will be done on to find out
where these kisspeptin fibers originate.
|
Schuster, Brian G. |
|
|
Home Institution: |
NCSU NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
Engineering
and Technology |
|
Department(s): |
Biological and
Agricultural Engineering |
|
Research Mentor(s): |
Matt
Veal/Biological and Agricultural Engineering |
|
Title of Presentation: |
Refining Vegetable Oil and
Grease for Biodiesel |
Biodiesel is a renewable substitute for petroleum diesel
fuel made from animal fats and vegetable oils. Through the process of
transesterification, the mono-, di-, and triglycerides in these fats and oils
will react with methanol in the presence of an alkaline catalyst to form methyl
esters, the active ingredient of biodiesel, as well as glycerin. Glycerin has
applications in food, pharmaceuticals, explosives, and personal care products.
However, the transesterification process can be significantly stunted by the
presence of free fatty acids (FFA’s). Triglycerides contain a glycerol backbone
attached to three fatty acid carbon chains. After a vegetable oil is used for
frying, the fatty acids break off of the glycerol and become free fatty acids,
which accumulate with increased frying activity. Alkaline catalysts such as potassium
hydroxide (KOH) are consumed by the FFA’s, making them useless for catalyzing
the transesterification reaction. This project investigates methods of
reconditioning oils with high FFA contents so they can be used to efficiently
produce biodiesel. Caustic stripping, acid transesterification, and
glycerolysis will be investigated as a means to pre-treat four oil samples of
varying FFA content. Caustic stripping,
the simplest method, consists of reacting all of the FFA’s with sodium hydroxide,
forming soaps. The soaps can be removed by centrifugation, leaving behind oil
with a lower FFA content. Acid transesterification uses the FFA’s to contribute
to the final product by reacting methanol with FFA’s in the presence of an
acidic catalyst, high temperatures, and high pressures. The final method,
glycerolysis, uses glycerol to react with the FFA’s to form mono- and
diglycerides, as well as water byproduct.
Zinc chloride catalyzes this reaction. The efficiency of each method as
well as an opinion on the best method to use to treat high FFA content oils
will be suggested as results become available.
|
Turner, John M. |
|
|
Home Institution: |
NCSU |
|
Program: |
HHMI Reaching Incoming Students Enrichment (RISE) |
|
College: |
Engineering
and Technology |
|
Department(s): |
Mechanical and Aerospace
Engineering |
|
Research Mentor(s): |
Scott
Ferguson/Mechanical and Aerospace Engineering |
|
Title of Presentation: |
Multivariate
Decisions and Optimization through the Engineering Design Process and Utility
Theory |
The engineering design process provides a structure
to develop multiple alternate solutions to a set of objectives. However, evaluating which solution is optimal
to the multivariate objective set is a common challenge. Utility quantifies how well the solution fits
consumers’ desires. During the study of
various methods of quantifying and comparing solution utility, a simplified
problem is considered for a multiple attribute air-drop protection system for
delicate equipment. As part of this
project, different components of the design process are investigated: task
clarification, requirements specifications and conceptual design, various
brainstorming techniques, background research, identifying functional
structures, preliminary material quantification, embodiment design, and
solution development. Defining the
appropriate strength of preferences and associated attribute weights offers the
best balance between ease of use, consistency, and accuracy. The Hypothetical Equivalents-Inequivalents
Method (HEIM) has particular promise in assigning relative utility and
evaluating non-linear preference or attribute scenarios and complex solution
decisions. Use of the HEIM method allows
for the optimization of the material selection, thickness, and replacement
scheme for the air-drop system.
Performance characteristics considered include cost, robustness,
accuracy, and environmental concerns.
Although uncertainty and variability is considered in the design and
preference modeling process, its complexity needs to be studied further. Other future work into model development will
help improve utility assessments and multi-attribute decisions, particularly in
situations where utility between attributes is not independent or where
subsidiary systems are involved.
[ Undergraduate Summer
Research Symposium Main Page ]
[ Agenda | Frequently Asked Questions
| Format Requirements
]
[ Summer Programs | Sponsors ]
[ Participant Listing
| Abstracts ]
Last modified June 2009 by Sharon E. Hunt