Abstracts 2011


Synthesis of a Dye-Sensitized Solar Cell Using

Platinum (II) Bipyridine Thiomaltol and Tin Oxide

 

Alex Nguyen

St. Mark’s School of Texas

Dallas, Texas

 

Faculty Mentor:

Dr. Patrick Farmer

Department of Chemistry and Biochemistry

Baylor University

 

Advances in solid-state solar cells have been made over the past few decades by manufacturing expensive three-junction monolithic silicon solar cells under high-risk conditions. While able to convert up to 43.5% of available light energy into electrical energy, current studies are investigating low-risk, cost-effective alternatives to solid-state photovoltaics. Dye-sensitized solar cells (DSSCs) offer an alternative that use the rare-earth transition metals ruthenium, osmium, and platinum. Advantages of metal-based dyes stem from their low symmetry and unique geometry. Many platinum-based dyes exhibit tunable features such as long-lived photo-excited states and luminescence in solution at room temperature, making them favorable sensitizers for DSSCs. Herein, a synthesis of [Pt(tbubpy)ttma]+ (tbubpy = ditert-butyl-bipyridine, ttma = dithiomaltol) from Pt(tbubpy)Cl₂ and maltol derivatives is reported. Characterization of the synthesized species is performed using 1HNMR and UV/Vis spectroscopy. Excited-state kinetics are investigated by steady-state luminescence, measuring emission intensities dependent on the concentration of the Pt(tbubpy)ttma in the absence of oxygen.

 

 

Infrared Spectroscopy of Gaseous Methane to Analyze Titan’s Atmospheric Temperatures

 

Brinal Kaul

Cinco Ranch High School

Katy, TX

 

Faculty Mentor:

Dr. Manzanares

Experimental Advisor:

David Camejo

Department of Chemistry/Biochemistry

Baylor University

 

As the depletion of Earth’s resources continues to threaten human existence, NASA scientists have become increasingly interested in exploring outer space. Saturn’s moon Titan is among the objects NASA has shown interest in studying on its search for extraterrestrial life and resources. Titan, recognized for its abundance of nitrogen and methane, is one of the known planets and satellites (other than Earth) that has a protective atmosphere from the Sun’s rays.  In this experiment, the Manzanares Lab group developed an experimental cryogenic cell to simulate the atmospheric conditions on Titan.  The cell was isolated inside a large chamber which allowed us to lower the temperature to Titan’s atmospheric temperature (94 Kelvin at its surface).  The Thermo Nicolet Nexus 670 FT-Infrared Spectrometer used in our experiment took the infrared spectrum of the methane gas in the cell at respectively decreasing temperatures.  We later ran theoretical simulations on how the results should have looked compared to the experimental data we obtained.  Our results from the ro-vibrational spectroscopy confirmed that methane gas at decreasing temperatures will show lower rotational energy states based on its ability to absorb infrared light.  The experimental and theoretical simulations confirm the measurements at Titan-like temperatures as low as 100 Kelvin. This temperature analysis, along with future studies, will help us understand Titan’s atmospheric conditions through the behavior of its methane gas.

 

 

 

A Mathematical Model of an E. coli Bacterium Outbreak

 

Jaime I. Lopez

South Texas High School for Health Professions

Mercedes, TX

 

Faculty Mentor:

Dr. Frank Mathis

Department of Mathematics

Baylor University

 

In May, 2011, Germany fell victim to a deadly E. coli strain. The outbreak remained centered in Northern Germany but continued to spread throughout the rest Europe. Using data supplied from the World Health Organization, a visual representation of the outbreak in Germany was created by plotting the number of cases over a period of 24 days. Our goal in the presentation was to build and test various mathematical models using difference and differential equations to describe the transmission behavior of the 2011 E. coli outbreak in Northern Germany. We determined the best fit to be a logistic difference equation with three parameters.

 

 

 

Plant Isotopes and Leaf Economic Spectrum

 

Jessie Barnett

Rockbridge County High School

Lexington, Virginia

 

Faculty Mentors:

Dr. Daniel Peppe

Department of Geology

Baylor University

 

Dr. Bill Hockaday

Department of Geology

Baylor University

 

The leaf economic spectrum suggests that physical properties, such as leaf area, petiole width, photosynthetic rate, and nutrient content all correlate to life span and the leaf mass per area of a leaf.  All plants try to maximize their nutrient uptake and fall somewhere on the spectrum.  On the fast return end of the spectrum, a plant has a short leaf life span, an increased photosynthetic rate, and the plant rapidly uptakes nutrients such as carbon and nitrogen.   These variables tend to fluctuate with altitude, vegetation, climate and rainfall.  My research focused on locally collected herbaceous angiosperms. We predicted that a leaf with a higher carbon and nitrogen content has a longer leaf span, larger petiole width and higher leaf mass per area. To test these hypotheses, many procedures were performed. The leaves were wet massed, dry massed, photographed and scanned into a program that calculated the petiole width and leaf area. We then punched holes in the leaves and weighed each leaf sample placed it into tin capsules representing each plant. We also took soil samples, and subjected them to various chemical reactions to help determine the isotopic ratio. Geochemical analyses are still being undertaken. The leaves will be combusted to find their carbon and nitrogen isotopic ratio and content. Understanding isotopic ratios is important because it relates to life span and the results of this research will help contribute to our understanding of the leaf economic spectrum.

Flow Separation and Heat Transfer over a Flat-Plate at Ultra-Low Reynolds Numbers

 

Mihir Pershad

Providence Senior High School

Charlotte, NC

 

Faculty Mentor:

Dr. Kenneth Van Treuren

Department of Mechanical Engineering

Baylor University

 

Flow separation from highly-loaded, low-pressure turbine blades at high altitudes continues to be a major concern in modern gas-turbine engines.  This flow separation results in an efficiency loss and, consequently, higher fuel consumption.  The Baylor University Suction Surface Wind Tunnel allows for the modeling of the streamwise pressure distribution found over the suction surface of a gas turbine airfoil.  The tunnel has a 20.3 cm (8 in) x 30.5 cm (12 in) x 121.9 cm (48 in) test section; the test plate measures 30.5 cm (12 in) x 85.1 cm (33.5 in).   Utilizing a plate with 16 surface static pressure taps, the static pressure was measured; the coefficient of pressure was then calculated for Reynolds numbers of 50K, 100K and 200K and compared to the Pratt and Whitney Pak-B experimental turbine blade with good agreement.  Separated flow was observed at the 75% to 85% location of the suction surface length.  An increased Reynolds number diminished the area of separation.  Heat transfer on the plate was then studied at each of the Reynolds numbers using a steady-state, gold foil, thermochromic liquid crystal technique.  Results showed the Nusselt numbers increased rapidly both upstream and downstream of the separated region, indicating steep temperature gradients are possible on the trailing edge of the Pak-B blade under separated flow conditions.  Thermal stressing caused by such abrupt thermal gradients can lead to turbine blade failure.  These findings indicate that techniques to mitigate flow separation must be developed to increase engine efficiency and prevent thermal failure of gas turbine blades operating at ultra-low Reynolds numbers.

Synthesis of a construct to purify a desired protein

 

Bianca Mulaney

IB at Bartow High School

Bartow, FL

 

Faculty Mentor:

Dr. Bryan Gibbon

Department of Biology

Baylor University

 

GCN2, or General Control Nonrepressed 2, is a protein kinase that senses amino acid deficiency and plays a key role in modulating amino acid metabolism in response to nutrient deprivation.  In yeast cells, it is known that the major downstream target of the GCN2 kinase is the GCN4 transcription factor; however, it is not known how the GCN2 kinase operates in maize and other eukaryotic organisms. The opaque2 transcription factor in maize is hypothesized to be the homolog of yeast GCN4, and therefore the target of the GCN2 kinase.  The purpose of this project was to synthesize an expression construct to purify the desired GCN2 protein – this purified protein would then be used to create antibodies that would further test GCN2 expression in corn. The mRNA fragments that coded for the amino (N-terminal) and carboxyl (C-terminal) domains of the GCN2 kinase were transcribed into cDNA; these cDNA fragments were amplified using PCR and were cloned into a plasmid entry vector. Once sequenced and characterized, the clones were recombined from the TOPO entry vector pCR8/GW to the pDEST17 destination vector using a recombinase. Competent E. coli cells were transformed with the construct, and colonies that were transformed with the correct expression vector were cultured to express the protein on a large scale. Sequencing of the expression vector showed incorrect gene orientation and thus did not express the correct protein; further screening of transformants will most likely discover expression constructs that can be used to create antibodies of interest.

 

 

 

Photochemical Crosslinking Agents for the Encapsulation of Islets

 

Erin Hein

Wheaton Warrenville South High School

Wheaton, Illinois

 

Faculty Mentor:

Dr. Robert Kane

Department of Biochemistry

Baylor University

 

A new treatment for diabetes involves the transplantation of islets, cell clusters which convert sugar to insulin, into the liver. A significant challenge with this therapy is the loss of islets due to the combative response of the patient’s immune system. This study aimed to identify and characterize chemical approaches to effectively modify islet surfaces, potentially preventing the patient’s immune system from attacking the islet. Two potential photochemical crosslinking agents were synthesized successfully. Compound 1, 6-Bromo-2-[2-(diethylamino)ethyl]-1H-benz[de]isoquinoline-1,3(2H)-dione, was synthesized by adding N,N-Dietyhletylenediamine to a suspension of 4-bromo-1,8-naphthalimide in ethanol. Compound 2, 6-bromo-2-(4-methoxybenzyl)-1H-benzo[de]isoquinolone-1,3(2H)-dione, was synthesized by adding 4-methoxybenzylamine to a suspension of 4-bromo-1,8-naphthalimide in ethanol. These compounds will be used in further study of islet modification. This study also aimed to quantify the extent of surface modification using different crosslinking reactions. Cross sections of these islets were analyzed to determine the percent of the surface area that was covered. These values were averaged with other islets that were covered by the same method and compared to a control group. Data analysis showed that the islets were best covered by the N-hydroxysuccinimide ester (NHS) method of crosslinking. However, a reduction method resulted in more complete coverage at high concentrations. Continuation of this project could lead to an optimization of the chemical modification of the islet, allowing it longer-term survival in the patient’s liver, converting sugar to insulin and functioning as an artificial pancreas.

 

 

 

Effects of Monomer Shape on the Formation of Fractal Aggregates

 

Jesse Kimery

Kimery Home School

Bangs, Texas

 

Faculty Mentor:

Dr. Lorin Matthews

Department of Physics

Baylor University

 

The coagulation of dust in plasma to form fractal aggregates is a vital process in many physical systems, notably planet formation.  Computer models of aggregate formation usually assume that dust particles are spherical; in nature, however, particles are often irregularly shaped.  We adjusted a MATLAB script which simulates the collisions of dust particles in plasma so that the code modeled particles of various shapes and sizes and accurately detected when the particles collided.  We then modeled the formation of aggregates from monomers of three different shapes—spheres, ellipsoids with two short axes and one long axis, and ellipsoids with two long axes and one short axis—and created three generations of these aggregates.  The first generation was formed by individual monomers colliding until the aggregate contained 20 monomers; the second generation was formed by the first-generation aggregates colliding with each other until the central aggregate contained 200 monomers; and the third generation was formed by the first-generation aggregates colliding with each other until the central aggregate contained 2000 monomers.  We analyzed the compactness factors and friction times of these aggregates to investigate the effect of particle shape on the formation of fractal aggregates in dusty plasma.  Continued analysis, which may include building aggregates with different shapes of monomers, building aggregates with a different distribution of monomer sizes, or building aggregates with charged monomers, will help scientists to understand the coagulation of dust in many physical processes, particularly planet formation.

 

 

 

Cellular Uptake of Silver Nanoparticles

 

Lauren Speller

Louisiana School

Natchitoches, LA

 

Faculty Mentors:

Dr. Erica Bruce

Department of Environmental Studies

Baylor University

 

Dr. Boris Lau

Department of Geology

Baylor University

 

The use of silver in nano-materials has become increasingly popular because of its unique physical and chemical properties – especially its antibacterial qualities. However, the toxicity of silver nanoparticles has been questioned. Many studies have shown that silver nanoparticles are toxic to cells with prolonged exposure. This toxicity has been attributed to nanoparticle-cell interactions, such as adsorption via high surface reactivity; however, little is known about the mechanisms of these interactions. This experiment will test the hypothesis that prolonged inhalation of silver nanoparticles is toxic to the cells in the epithelial lining of the human lung. In vitro studies of human bronchoalveolar carcinoma derived cells (A549) are used to quantify the surface adsorption and the uptake of the nanoparticles. The results of this study can be applied to manage the risk associated with occupational inhalation exposure to silver nanoparticles. By limiting the risk factor of exposure to the silver nanoparticles for extended periods of time, regulators will be able to properly manage the risk of exposure to silver nanoparticles in an occupational setting.

 

 

 

 

Synthesis of a Fluorinated 2-Aryl-3-Aroyl Indole Derivative

as a Potential Vascular Disrupting Agent

 

Siri Ancha

Joplin High School

Joplin, Missouri

 

Faculty Mentor:
Dr. Kevin G. Pinney

Department of Chemistry & Biochemistry

Baylor University

 

Cancer is the second leading cause of death in the United States. An emerging area of research explores the use of vascular disrupting agents (VDAs) as potential chemotherapeutic agents for the suppression of tumor growth.  The tumor microenvironment is characterized by disorganized and chaotic vasculature, compared to the more organized vasculature associated with normal, healthy cells.  VDAs function by binding to the endothelial cell tubulin α, β subunits and subsequently disrupting the formation of microtubules.  This leads to morphology changes (from flat to round) in the endothelial cells, which ultimately occludes vasculature, thus starving the tumor of oxygen.  A class of small molecule VDAs derived from the combretastatin family of natural products encompasses the indole core structure.  Certain analogs have shown promising results in damaging tumor vasculature.  This current research was aimed at the design, synthesis, and biological evaluation of new indole derivatives.  Through a series of chemical reactions, a fluorinated indole analog was successfully synthesized and characterized through common organic methods including TLC, 1H NMR, 13C NMR, and 19F NMR.  Further studies carried out in collaboration with the Trawick Research Group at Baylor University will evaluate the ability of this compound to inhibit tubulin assembly.  In addition, its cytotoxicity will be determined against a selection of human cancer cell lines.