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BIOL2018YATES4553 BIOL

The Beetle Invasion of the Texas Horned Lizard's (P. cornutum) Diet

Type: Undergraduate
Author(s): Jessica Yates Biology Rachel Alenius Biology Dean Williams Biology
Advisor(s): Dean Williams Biology
Location: Session: 1; Basement; Table Number: 4

poster location

The Texas horned lizard (Phrynosoma cornutum) has always been believed to be an ant specialist, especially on harvester ants. However, a population of horned lizards in south Texas seem to have a more diverse diet consisting of other insects and arachnids. The goal of this project is to build a DNA library of order Coleoptera (beetles) that are preyed upon by these horned lizards. This DNA library will be compared to DNA extracted from horned lizard scat so that we can identify which species of beetles these lizards are eating. For this process, I isolated DNA from 244 beetles collected in pit fall traps from Kenedy and Karnes City, amplified the cytochrome oxidase I (COI) gene, and sequenced it. I compared the processed sequences to those available on GenBank and BOLD (Barcode of Life Database) to identify the species of beetle.

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CHEM2018BARNETT5923 CHEM

Spectroscopic assays of a novel neurodegenerative therapeutic agent

Type: Undergraduate
Author(s): Maddie Barnett Chemistry & Biochemistry Hannah Johnston Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Session: 1; 2nd Floor; Table Number: 1

poster location

Oxidative stress in the brain is a known contributor to the development of neurodegenerative diseases, including Alzheimer’s. The focus of this project is to target the amyloid-β plaque formations and reactive oxygen species (ROS) derived from mis-regulated metal-ions that lead to disease-causing oxidative stress. The present investigation measures both the antioxidant reactivity and metal chelating ability of 1,4,11,13-tetra-aza-bis(2,6-pyridinophane)-8,17-ol (L4).  L4 contains two radical scavenging pyridol groups along with a metal-binding nitrogen rich ligand system.  It was hypothesized that increasing the number of pyridol groups on the ligands in our small molecule library would increase the radical scavenging activity, which in turn may provide cells protection from oxidative stress.  The radical scavenging ability of L4 was quantified using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. This was compared to other radical scavenging small molecules to evaluate the effect of the additional radical scavenging group on the antioxidant activity.  The interaction of L4 with redox active metal-ions such as copper(II) was also evaluated using the coumarin-3-carboxylic acid (CCA) assay to show the molecule’s ability to target mis-regulated metal-ions in diseased tissues. With the end goal being to develop a potential biological therapeutic agent, metabolic stability studies were also performed.

(Poster is private)

CHEM2018BODIFORD8780 CHEM

Drug delivery and degradation behavior of nanostructured porous silicon and polycaprolactone porous fiber composites

Type: Graduate
Author(s): Nelli Bodiford Chemistry & Biochemistry Steven McInnes Chemistry & Biochemistry Nathan Shurtleff Chemistry & Biochemistry Nicolas Voelcker Chemistry & Biochemistry
Advisor(s): Jeffery Coffer Chemistry & Biochemistry
Location: Session: 1; 1st Floor; Table Number: 7

poster location

The combination of inorganic porous silicon (pSi) and flexible biocompatible polymers has been shown to yield more beneficial hybrid scaffolds for tissue engineering (i.e. use of synthetic materials to facilitate healing). PSi has a variety of tunable properties, including pore size, pore volume and non-toxic degradation. The addition of a biocompatible polymer such as polycaprolactone (PCL) can provide control over shape and serve as an additional drug delivery component.
In this work, composite materials consisting of oxidized porous silicon (ox-pSi) with a particle size of ~ 30 μm and pore size of 40-100 nm and PCL porous fibers. Porous fibers were fabricated using an electrospinning method into sheets of desired thickness (0.1-0.4 mm), fiber diameter 3-4 μm, and fiber pore size 300-500 nm. Ox-pSi particles previously loaded with the anticancer drug-camptothecin (CPT) were placed between two sheets (6 mm in diameter each) and sealed at the edges, resulting in ~65% loading of ox-pSi. Drug release from the ox-pSi particles alone and ox-pSi/porous PCL fiber composites was monitored fluorometrically in phosphate buffered saline (PBS), showing a distinct release profile for each material.
Ox-pSi/p-PCL fiber composites release a CPT payload in accordance with the Higuchi release model and showed a significant decrease in burst effect compared to ox-pSi particles only. In addition, composite evolution after 5 weeks in PBS at 37 oC was examined using gravimetry, differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). Overall weight loss of the composites was about 50%, mainly attributed to pSi particles dissolution and some polymer hydrolysis. Preliminary DSC results show that high surface area porous PCL fibers are less crystalline compared to solid PCL fibers, suggesting a faster hydrolysis route.

(Poster is private)

CHEM2018BURNETT36214 CHEM

Non-Innocent redox activity of the glycine modified DOTA scaffold and the impact on Eu3+/2+ electrochemistry

Type: Graduate
Author(s): Marianne Burnett Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Session: 1; 2nd Floor; Table Number: 8

poster location

Europium contrast agents have been extensively investigated as an alternative to typical Gd3+ species for imaging. This is due to the dual imaging modalities which can accessed dependent on the oxidation state of the europium metal center (T1 or PARACEST). To achieve these functionalities, the europium containing complex must be stable enough to support both oxidation states (+3 and +2). In collaboration with UTSW, an electrochemical investigation was completed to understand the effects of the ligand environment on the metal center as a direct result of glycine modification to the ligand scaffold, DOTA. Increasing amide functionalities in close proximity to the europium core result in a positive shift in the potential in comparison to the acetate arms associated with DOTA. Furthermore, the addition of the glycine moiety to the pendant arms results in redox activity of the ligand itself, making the ligand non-innocent in nature. Additionally, a crystal structure of Eu4 (the tetraglycinate DOTA derivative) was obtained and compared to known lanthanide complexes.

(Poster is private)

CHEM2018CIEKER32577 CHEM

EN ROUTE TO DESIGNER MEDIA: synthetic and spectroscopic studies on ionic and eutectic solvents

Type: Undergraduate
Author(s): Chris Cieker Chemistry & Biochemistry Marlius Castillo Chemistry & Biochemistry David Edwards Chemistry & Biochemistry Nico Prieto Chemistry & Biochemistry
Advisor(s): Sergei Dzyuba Chemistry & Biochemistry
Location: Session: 2; 3rd Floor; Table Number: 2

poster location

Non-conventional solvents, such as room-temperature ionic liquids and deep-eutectic solvents, have attracted a lot of attention in recent years due their diverse applications in various areas of sciences, medicine and engineering. The ability to control physical properties of these solvents by simply adjusting their structure and/or the ratio of the components favorably distinguishes ionic and eutectic solvents from traditionally used molecular solvents as it allows to custom design specific types of media for given applications.

This presentation will highlight our efforts on various aspects of the synthesis of ionic liquids and deep-eutectic solvents as well as it will describe our investigations on the physical properties and nanostructural organization of these liquids using environmental probes, such as those that feature BODIPY and aza-BODIPY motifs. In addition, our initial studies on the design of multiphase systems that utilize ionic, eutectic and molecular solvents will be presented.

(Poster is private)

CHEM2018DACHILLE23489 CHEM

Synthesis and Characterization of Europium-doped Cerium Oxide Nanotubes

Type: Graduate
Author(s): Anne D'Achille Chemistry & Biochemistry Jeff Coffer Chemistry & Biochemistry
Advisor(s): Jeff Coffer Chemistry & Biochemistry
Location: Session: 1; 3rd Floor; Table Number: 10

poster location

Cerium (IV) oxide, or CeO2, nanomaterials have displayed antioxidant and enzyme mimetic activities due to a Ce3+/Ce4+ redox capability enhanced through oxygen vacancies and mobility. Tri-valent, fluorescent ions such as Eu3+ increase the Ce3+/Ce4+ ratio and oxygen vacancy concentration, while contributing fluorescent properties to the nanomaterial. The combination of these attributes make europium doped cerium oxide (EuCeO¬2) nanomaterials appealing candidates for various biological applications.
To complement our earlier efforts on the synthesis and properties of EuCeO2 nanowires, nanorods, and nanocubes, this presentation addresses a new, complementary structure, EuCeO2 nanotubes. The nanotubes are prepared via deposition and subsequent oxidation of Eu-doped Ce(OH)3 to form a EuCeO2 shell on sacrificial ZnO nanowires.
Previous synthetic routes to CeO2 nanotubes have been reported featuring carbon nanotubes as sacrificial templates, the etching of cerium-based nanorods, and other less-common methods . These routes have struggled with clear evidence for distinct nanotube formation, as well as control over nanotube dimensions. Our use of a ZnO core allows for facile manipulation of inner diameter and length of the nanotube following etching of the core.
The synthesized nanotubes were characterized using scanning and transmission microscopy (SEM and TEM) for morphology, energy dispersive x-ray (EDX) for elemental composition, and photoluminescence to track europium fluorescence. Synthesized nanotubes had inner diameters from 40 nm to 200 nm, based on the ZnO core. Following synthesis and characterization, the nanotubes will be tested for use as a drug delivery vector, using ibuprofen as a model.

(Poster is private)

CHEM2018DINH49477 CHEM

Genetic selection of leucyl-tRNA synthetase for the production of fluorescent proteins in living cells

Type: Undergraduate
Author(s): Viet Dinh Biology Andrea Guedez Chemistry & Biochemistry
Advisor(s): Youngha Ryu Chemistry & Biochemistry
Location: Session: 1; 3rd Floor; Table Number: 1

poster location

This project is aimed to modify a leucyl-tRNA synthetase (LeuRS) to incorporate fluorescent amino acids into proteins to produce fluorescent proteins in living cells. Fluorescent proteins are useful because they are easily analyzed and tracked in living organisms. In a small scale, we successfully prepared the library of LeuRS variants in which five amino acids are randomized in the leucine-binding site of a functional LeuRS without its editing domain. Currently, we are working on a large scale production of viable bacterial cells that cover the whole diversity of library (at least 34 million different LeuRS molecules). Initially, we attempted two-step process in which an N-terminal library fragment (for two randomized amino acids) is generated first and a C-terminal fragment (for three randomized amino acids) is added later. However, this two-step cloning process did not produce enough viable cells to cover all the possible variants. In a new approach, a complete library of LeuRS will be produced by overlapping extension PCR and introduced to E. coli in a single step to ensure highest possible transformation efficiency. Consequently, the library of LeuRS variants will be subject to a genetic selection experiment to obtain LeuRS variants that incorporate only fluorescent amino acids into proteins.

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CHEM2018FAHIM52071 CHEM

Amplification of salt-induced protein diffusiophoresis by varying salt nature

Type: Graduate
Author(s): Aisha Fahim Chemistry & Biochemistry
Advisor(s): Onofrio Annunziata Chemistry & Biochemistry
Location: Session: 1; Basement; Table Number: 8

poster location

Diffusiophoresis is the migration of a relatively large particle (e.g., protein, polymer, nanoparticle) induced by a gradient of salt concentration. The salt-induced diffusiophoresis of lysozyme, a model protein, at pH 4.5 and 25 °C was examined as a function of salt concentration for three chloride salts: NaCl, KCl and MgCl2. Diffusiophoresis coefficients were theoretically extracted from experimental multicomponent diffusion data by applying irreversible thermodynamics. A selected mass-transfer process was theoretically examined to show that concentration gradients of MgCl2 produce significant lysozyme diffusiophoresis. The dependence of lysozyme diffusiophoresis on salt nature was theoretically examined and linked to protein charge. The effect of salt type on hydrogen-ion titration curves was experimentally characterized to understand the role of salt nature on protein charge. Our findings indicate that diffusiophoresis may be exploited for diffusion-based separation of proteins in the presence of salt concentration gradients and for the enhancement of protein adsorption onto solid surfaces relevant to biosensing applications.

(Poster is private)

CHEM2018GUEDEZ35919 CHEM

Caffeine-dependent gene regulation by synthetic caffeine riboswitches

Type: Graduate
Author(s): Andrea Guedez Chemistry & Biochemistry Matt Sherman Chemistry & Biochemistry
Advisor(s): Youngha Ryu Chemistry & Biochemistry
Location: Session: 1; Basement; Table Number: 2

poster location

The randomization of 11 bases in the theophylline-binding domain generated a library containing millions of different theophylline riboswitch variants. The dual genetic selection of this molecular library successfully led to the identification of a caffeine-specific synthetic riboswitch. When a chloramphenicol-resistance gene was expressed under control of this caffeine riboswitch, E. coli cells showed chloramphenicol resistance only in the presence of caffeine. For a colorimetric or fluorescence assay, the caffeine riboswitch gene was inserted upstream of the B-galactosidase (LacZ) or green fluorescence protein (GFP) gene, respectively. When tested with various concentrations of caffeine, the enzymatic activity of LacZ or the fluorescence intensity of GFP was proportional to the amount of caffeine, clearly indicating the caffeine-dependent gene regulation by the caffeine riboswitch. The caffeine synthetic riboswitch can be further developed as a biosensor to detect caffeine in complex biological samples such as urine and blood.

(Poster is private)

CHEM2018HASSAN17248 CHEM

Synthesis of a Triazine derivative analog of the HIV Drug Abacavir.

Type: Undergraduate
Author(s): Asim Hassan Chemistry & Biochemistry
Advisor(s): Eric Simanek Chemistry & Biochemistry
Location: Session: 1; Basement; Table Number: 3

poster location

Abacavir or Ziagen, is an antiretroviral medicine that is used in conjunction with other
medicines to treat HIV. Although it is not a cure, it has been clinically proven to be
effective in diminishing the rate of HIV replication. The synthetic process of creating
Abacavir is both timely and costly, so therefore a new synthetic process has been
created to generate a chemical analog (specifically a triazine derivative) that is cheaper
to produce that can be if not potentially more chemically effective than Abacavir. Once
the analog is produced, a series of analytical tests will be done on a micro organismic
level to determine if the analog is both effective and safe enough to be used in human
clinical studies further down the road.

(Poster is private)

CHEM2018HAUGEN286 CHEM

Production Of Disubstituted Isoquinoline Derivatives: Steps Toward The Synthesis Of A Pratosine Analog

Type: Undergraduate
Author(s): Avery Haugen Chemistry & Biochemistry
Advisor(s): David Minter Chemistry & Biochemistry
Location: Session: 1; 2nd Floor; Table Number: 5

poster location

The pyrrolophenanthridone alkaloid pratosine is a natural product related to hippadine, which is known to be a powerful but reversible inhibitor of spermatogenesis in rats. Hippadine has also shown cardiovascular as well as anticancer activity. Given the structural similarities between the two molecules, it is expected that pratosine and hippadine will demonstrate similar biological effects. Our work toward a laboratory synthesis of pratosine will facilitate large-scale production thus affording sufficient quantities of the material for a complete pharmacological study of its properties. Although we have a synthetic plan for preparing pratosine, several reactions have failed due to solubility problems. This research focuses on solving these problems by using an alternate starting material. The commercially available compound vanillin, which is extracted from vanilla beans, is a simple and inexpensive aldehyde with an appropriate structure for attaching other groups that should improve the solubility properties of several of the synthetic intermediates. Our goal is to find a specific substituent that will provide the required characteristics but which can also be removed later to generate the final product.

(Poster is private)

CHEM2018LE31589 CHEM

Silicon Nanotubes as A Platform for Platinum Nanocrystal Deposition

Type: Graduate
Author(s): Nguyen Le Chemistry & Biochemistry
Advisor(s): Jeffery Coffer Chemistry & Biochemistry
Location: Session: 1; 3rd Floor; Table Number: 3

poster location

Porous silicon (pSi) is a unique nanostructured form of the elemental semiconductor Si. Due to its useful properties governed by its surface chemistry and porous morphology, pSi has been studied in the last few decades in diverse fields extending from electronic device technology to bio-relevant applications.1 Recently, one-dimensional porous nanotubes based on elemental Si (pSiNTs) with a tunable structure (sidewalls, inner void space and lengths) have been successfully synthesized.2 The well-defined structure of pSiNTs offers ample opportunities to study newly emerging properties of this material and innovative applications in multiple areas. For example, recent reports have revealed the use of SiNTs as an efficient template for loading superparamagnetic nanoparticles (Fe3O4), lithium storage and cycling, as well as acting as a template for formation of organometal perovskite nanostructures.3-5
Platinum (Pt) nanoparticles, both free-standing as well as anchored on various surfaces, have attracted widespread attention in nanocatalysis, electronics, and chemotherapeutics.6 In this work, it is suggested that pSiNTs after being functionalized with 3-(aminopropyl)triethoxysilane (APTES) can serve as a platform for Pt nanocrystal (Pt NC) formation. Particularly, incubation of APTES-functionalized SiNTs in potassium tetrachloroplatinate (II) (K2PtCl4) solution under ambient conditions subsequently yields Pt nanoclusters with sizes ranging from 1-3 nm on SiNTs. From high-resolution transmission electron microscopy (HRTEM), nanocrystals with characteristic lattice spacings associated with Pt (d = 0.21 nm) are observed on the nanotubes. The amount of Pt deposited on SiNTs can be sensitively tuned from 20-60 wt% (characterized by TEM Energy Dispersive X-ray Analysis, EDX) by varying concentration of K2PtCl4 and immersion time in this Pt salt precursor.
These findings suggest a new approach to prepare Pt NCs that are of potential benefit to a broad number of applications by using pSiNTs as a template. Further investigations into the properties of the newly discovered Pt NCs-SiNT composites are imperative to evaluate useful applications of this material.
REFERENCES
[1] Porous Silicon for Biomedical Applications, H. Santos, Ed. Cambridge: Woodhead Publishing, 2014.
[2] X. Huang, R. Gonzalez-Rodriguez, R. Rich, Z. Gryczynski, J.L. Coffer, Chem. Commun., 2013, 49, 5760-5762.
[3] P. Granitzer, K. Rumpf, R. Gonzalez, J. Coffer, M. Reissner, Nanoscale Res. Lett. 2014, 9, 413.
[4] R. Gonzalez-Rodriguez, N. Arad-Vosk, N. Rozenfeld, A. Sa'ar, J. L. Coffer, Small, 2016, 12, 4477-4480.
[5] A. T. Tesfaye, R. Gonzalez, J. L. Coffer, T. Djenizian, ACS Appl. Mater. Interfaces, 2015, 7, 20495-20498.
[6] A. Chen, and P. Holt-Hindle, Chem. Rev., 2010, 110, 3767-3804.

(Poster is private)

CHEM2018LE33668 CHEM

New Eco-Friendly Porous Silicon Nanomaterials as Sustained Release Fertilizers

Type: Undergraduate
Author(s): Linh Le Chemistry & Biochemistry
Advisor(s): Jeffery L. Coffer Chemistry & Biochemistry
Location: Session: 2; 3rd Floor; Table Number: 10

poster location

Urea is a low-cost, water-soluble fertilizer that is used as the major source of nitrogen in agricultural production. However, the problem with leaching, in which urea in soil is rapidly washed away through rain and irrigation, results in inefficiency in nutrient absorption, low crop yield, poor harvest, and economic failure for farmers (Broadbent 1958), as well as the environmental pollution of groundwater by the release of excessive amounts of nitrate, which adversely affects this non-rechargeable water source. Therefore, recent research attempts to design a suitable system to prolong the release of urea from water in soil to improve soil fertility, agricultural economy, and ground water protection. A prospective approach is to integrate urea into a stable matrix that releases the desired material with an optimal time window.

Porous Silicon (pSi) has been studied as the material of diverse interest, due to its surface chemistry and porous morphology that has promoted many nanotechnology advances, in conjunction with its biocompatibility and biodegradability (Canham 2014). Since pSi degrades slowly in aqueous media and does not react with the soil component, it is selected to be a possible matrix for sustaining urea release. pSi is believed to interact with urea via hydrogen bonds (via surface silanol species), and thus its porous structure is the key to trap urea particles for relatively long periods in water, while exposing the fertilizer to plants. This bioactive pSi material is produced from the eco-friendly Tabasheer-derived silica, during which pSi porosity is maintained (Kalluri et al. 2016). Loading of urea into pSi is carried out using ethanol as a solvent, with theoretical loadings ranging from 27-33% of the composite mass. Release kinetics of urea from water is currently being investigated using highly sensitive colorimetric assay that applies Jung’s method (Jung et al. 1975).

The urea-loaded pSi prepared in these experiments were characterized using several different techniques. X-ray diffraction (XRD) evaluates the crystallinity of pSi after fabrication, with the presence of three peaks consistent with a cubic unit cell structure [Si (111), (220), and (311)]. Thermal gravimetric analysis (TGA) gives the mass loss percentage between melting (132oC) and boiling (203oC) points of urea, which represents the practical loading of urea in a given sample. The results deviate 1-2% from the theoretical loading percentage. TGA also shows the stability of the composite over two months at room temperature, with the recent loading measurement analyses consistent with the previous ones. Differential scanning calorimetry (DSC) analysis confirms that the urea is incorporated in the pSi matrix. Loading and characterization studies were conducted in triplicate to ensure reproducibility of results.

(Poster is private)

CHEM2018MARCUS14788 CHEM

Manipulating the pyrimidine ring of the Burixafor medication to a triazine ring and testing the ease of synthesis and bioavailability of this similar molecule

Type: Undergraduate
Author(s): Weston Marcus Biology
Advisor(s): Eric Simanek Chemistry & Biochemistry
Location: Session: 2; Basement; Table Number: 6

poster location

Burixafor is an orally bioavailable inhibitor of CXC chemokine receptor 4, thereby preventing the binding of stromal derived factor-1 and subsequent receptor activation. The inhibition of this receptor may induce the mobilization of hematopoietic stem and progenitor cells from the bone marrow into peripheral blood. Burixafor is in the initial trials of clinical testing and its mode of action may prove to be effective in hematopoietic stem cell transplantation, chemotherapy sensitization, and other ischemic diseases. Its sales exceed one billion dollars per year, establishing itself as a drug worth investigating further.

What makes the chemical itself worth studying is its central pyrimidine ring. Whether or not this unsymmetrical nitrogen-containing ring is essential to its bioavailability remains to be seen, but a more efficient and cost effect route exists in its synthesis utilizing a triazine ring as opposed to a pyrimidine ring. Cyanuric chloride is a cheap, commercially available reagent that is very susceptible to nucleophilic substitution at three different sites. Burixafor and its subsequent modifications that we are wishing to make are protected by patent WO 2009131598 A1, but it is worth investigating further because our modification has not been extensively analyzed. We also believe that we can streamline its synthesis into a more economically feasible and shorter route, which would increase the novelty of this drug.

CHEM2018MEHMOOD32880 CHEM

An Orbital-Overlap Complement to Atomic Partial Charge

Type: Graduate
Author(s): Arshad Mehmood Chemistry & Biochemistry
Advisor(s): Benjamin G. Janesko Chemistry & Biochemistry
Location: Session: 2; 1st Floor; Table Number: 5

poster location

Atomic partial charges obtained from computed wavefunctions are widely used for interpreting quantum chemistry simulations and chemical reactivities of molecules, solids, surfaces, and nanoparticles. In many cases, partial charge alone gives an incomplete picture of reactivity: PhS(-) is a better nucleophile compared to PhO(-) in SN2 reactions with MeI, though PhO(-) has a more negative charge on the nucleophilic atom, the carbons of benzene and cyclobutadiene, or those of diamond, graphene, and C60, possess nearly identical partial charges and very different reactivities, deprotonated amides perform nucleophilic attack via the less negative nitrogen, rather than the more negative oxygen, in anionic cyclization of o-alkynyl benzamides, halide anions F(-), Cl(-), Br(-) and I(-) have identical charges but different nucleophilicities, carbons in aromatic benzene and anti-aromatic cyclobutadiene have nearly identical partial charges, but different reactivities. Our atomic overlap distance complements computed partial charges by measuring the size of orbital lobes that best overlap with the wavefunction around an atom. Compact, chemically stable atoms tend to have overlap distances smaller than chemically soft, unstable atoms. Combining atomic charges and overlap distances captures trends in aromaticity, nucleophilicity, allotrope stability, and substituent effects. Applications to recent experiments in organic chemistry (counterintuitive Lewis base stabilization of alkenyl anions in anionic cyclization), nanomaterials chemistry (facile doping of the central atom in Au7 hexagons) and selective binding of ligands in proteins illustrate this combination’s predictive power.

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CHEM2018MONTOYA23430 CHEM

Steps Towards the Synthesis of Pancratistatin-Type Analogs

Type: Graduate
Author(s): Adam Montoya Chemistry & Biochemistry
Advisor(s): David Minter Chemistry & Biochemistry
Location: Session: 2; 1st Floor; Table Number: 4

poster location

Amaryllidaceae isoquinoline alkaloids, as well as their analogs, have long been of interest in research for drug discovery due to their biologically active nature. Many of these compounds have been found to be anti-tumor agents.1 Moreover, there have also been studies that show the effectiveness of these molecules against diseases such as Yellow Fever and other RNA-containing flaviviruses.2 Though these compounds are pharmaceutical drug prospects, their low natural abundance lowers that potential.3 For this reason, many synthetic chemists have pursued novel routes to synthesize a wide variety of these compounds.
Techniques toward the synthesis of Pancratistatin-type natural products are presented herein. Manipulations were tested and optimized on a model system to save both time and funds while developing a synthetic pathway to be utilized in the formation of more complex compounds. Setbacks such as controlling the stereochemistry of a tetrasubstituted alkene reduction have been encountered. However, adjustments are being made to avoid such difficulties. Ideally, the proposed scheme will ultimately allow for the synthesis of multiple biologically active Phenanthridone analogs.

(Poster is private)

CHEM2018NIEBUHR15382 CHEM

Functional modifications and electronic influences on tetra-aza macrocyclic Cu(II) complexes

Type: Undergraduate
Author(s): Brian Niebuhr Chemistry & Biochemistry Marianne Burnett Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Session: 1; 1st Floor; Table Number: 5

poster location

A library of novel tetra-aza macrocyclic molecules, specifically 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene derivatives, capable of chelating metal ions in vivo have been synthesized. Applications of these complexes are currently being pursued as a 1) therapeutic focusing on radical scavenging and metal chelation and 2) diagnostic tool such as magnetic resonance imaging (MRI) contrast agents when complexed with specific metal ions. However, a full study of the electronic effects imparted by substitution to the pyridyl moiety (position 13) and the subsequent impact on the metal center have not been explored. The objective of the present study is to characterize metal complexes of four tetra-aza macrocyclic metal chelating molecules. The pyridyl functional groups studied include: A) unmodified pyridyl, B) p-hydroxyl, C) p-nitrile, and D) m-hydroxyl modified pyridyls on a pyclen base structure (position 13). Notable progress has been made in developing an optimal procedure for obtaining copper (II) complexes and will be presented. Analysis of the resulting copper (II) complex of the p-nitrile tetra-aza macrocycle indicate a six-coordinate metal center based on X-ray diffraction. UV-Visible spectroscopy and electrochemistry help to confirm donor strength among the ligand series as well as a comparison to other tetra-aza macrocycles. Ultimately, this project is focused on understanding the electronic contribution of these functional groups on the pyridine ring and the influence of the ligand and complexed systems as therapeutic and diagnostic agents.

(Poster is private)

CHEM2018OCHOA41556 CHEM

Intramolecular de Mayo Photocyclization: The Total Synthesis of Hippadine and Pratosine

Type: Graduate
Author(s): Charles Ochoa Chemistry & Biochemistry
Advisor(s): David Minter Chemistry & Biochemistry
Location: Session: 2; 2nd Floor; Table Number: 7

poster location

Hippadine and pratosine are lycorine-type pharmacologically active Amaryllidaceae alkaloids. Various total syntheses of these natural products have been developed. However, most of these synthetic routes require prohibitively expensive materials and/or achieve yields that are subpar, making these schemes unlikely to be used in an industrial setting. Current research involves developing better synthetic methods for these two alkaloids starting with a 6,7-disubstituted isoquinoline. These syntheses are appealing since they utilize readily available starting materials and avoid expensive catalysts. The key step in the synthetic scheme centers around an intramolecular de Mayo photocyclization which involves a reaction between an alkene moiety in the isocarbostyril system and a 1,3-diketone (a functionalized tether on nitrogen), which forms a third ring in the structure of the molecule. When the photochemical reaction was attempted, an unexpected cyclic photoproduct was obtained; fortunately, this product is a cyclic hemiketal of the expected 1,5-dicarbonyl compound. A base-catalyzed aldol addition affords the final ring in the system; dehydration of this product affords a β-enone that can be transformed to a diene. Oxidation of the diene with DDQ affords the target natural products after simple chromatographic purification. This new synthetic pathway circumvents the need for catalysts that are either expensive or contain metals such as palladium or iridium; moreover, our method allows for the synthesis of various natural and unnatural alkaloids in high yields by modification of the N-tether.

(Poster is private)

CHEM2018PARKER27356 CHEM

Enhancing Blood-Brain Barrier Permeability Through Glycosylation of Antioxidant Compound

Type: Undergraduate
Author(s): Jack Parker Chemistry & Biochemistry Marianne Burnett Chemistry & Biochemistry Hannah Johnston Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Session: 1; 1st Floor; Table Number: 1

poster location

Molecules previously developed by the Green Research Group (L2 and L3) have been shown to reduce reactive oxygen species (ROS) through multiple pathways of activity. Although unclear if ROS is the only source, Alzheimer’s disease and other neurodegenerative disorders are known to be initiated from the formation of these ROS. For these molecules to appropriately execute their antioxidant and radical scavenging ability, they must enter into the brain where the damaging ROS are located. The blood brain barrier (BBB) is a natural obstacle that prevents toxins and infections from reaching the brain. The L2 and L3 ligands must penetrate this barrier to be in the desired site of action to reduce the number of ROS. Addition of a glucose moiety to other therapeutic molecules has been shown to increase permeability across the BBB. The target of this project is to enhance these synthetic pathways of glycosylation and increase product yield. Initially, direct addition of the glucose moiety to the L2 and L3 molecules was achieved. However, challenges with purification techniques suggested a different route to purification or design should be considered and one new route is presented here. With L2 and L3 being inherently hydrophilic, addition of an aliphatic chain to the hydroxyl group of L2 or L3 should increase the hydrophobicity of the molecule allowing for different purification techniques, which can ultimately be glycosylated to give purified desired compounds.

(Poster is private)

CHEM2018RODRIGUEZ3379 CHEM

Formation of New Perovskite Nanostructures Templated by Porous Silicon

Type: Undergraduate
Author(s): Adriana Rodriguez Chemistry & Biochemistry
Advisor(s): Jeff Coffer Chemistry & Biochemistry
Location: Session: 2; Basement; Table Number: 13

poster location

A recent and promising development in solar energy involves a class of materials known as organometal halide perovskites, capable of efficiencies (>20%) comparable to the current industry standard of silicon. These materials also demonstrate strong light emission, a key property associated with energy-efficient sources of lighting, suggesting potential applications in light-emitting devices such as light-emitting diodes (LED). The goal of this project was to investigate the fundamental photoluminescence (PL) properties of perovskites housed in a nanoporous material known as semiconducting porous silicon (pSi).

pSi provides a nanoscale template to control the growth of the light-emitting perovskite structure and is an electrically-responsive host matrix, ideally regulating the flow of charge to/from the perovskite. Samples were prepared within the pores of surface oxidized pSi and hydride-terminated pSi, each with a mesoporous width in the 5 – 50 nm range. The perovskite-loaded pSi was fabricated through solution-loading of perovskite precursors into warmed pSi (60ºC), removal of excess reactant solution, and drying. While perovskites can feature a wide range of halide compositions (including mixed halides), this research thus far has focused on methylammonium lead iodide (MAPbI3) perovskite.

These perovskite nanostructures formed within pSi were characterized using a variety of techniques. Following synthesis, the stability of each prepared sample was monitored for 3 weeks through tracking its relative photoluminescence intensity at its maximum value. Perovskite morphology was evaluated by SEM (scanning electron microscope) and TEM (transmission electron microscope) imaging, crystalline structure was evaluated by XRD (x-ray powder diffraction), and elemental analysis was evaluated by EDX (energy-dispersive x-ray spectroscopy).

In this study, SEM imaging showed consistent perovskite particle size and ununiformed perovskite infiltration. It is found that the emission intensity for MAPbI3 formed within hydride-terminated pSi (at ~730nm) and oxidized pSi (at ~740nm) were relatively stable over a 3 week period, but the emission intensity for perovskite microrods formed in the absence of any pSi template actually decreased over time. More detailed measurements of the long term stability of these new nanoscale materials are currently under evaluation.

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CHEM2018TRETTE12261 CHEM

Fabrication Methods of Polycaprolactone (PCL) Fibers and their Thermal Properties

Type: Undergraduate
Author(s): Sayre Trette Chemistry & Biochemistry Nelli Bodiford Chemistry & Biochemistry Nathan Shurtleff Chemistry & Biochemistry
Advisor(s): Jeffery Coffer Chemistry & Biochemistry
Location: Session: 2; Basement; Table Number: 9

poster location

Significant increases in average life expectancy in the last century have brought a growth in human illnesses related to aging: chronic wounds, bone diseases, eye diseases and cancer. In this work, we demonstrate fabrication of biodegradable polymer scaffolds that can be used for drug delivery and tissue engineering to treat the above-mentioned ailments. Tissue engineering can be defined as the use of a combination of engineering and materials methods and appropriate biochemical factors to improve or replace biological tissues.
This project includes fabrication of solid and porous fibers from the biocompatible PCL polymer. This polymer is currently used for surgical sutures, nerve guides and three-dimensional scaffolds for use in tissue engineering. The drug release rate is faster when it is loaded into porous PCL fibers compared to solid PCL fibers, creating an advantage for porous fiber fabrication. Use of a technique known as electrospinning of a solution of PCL and chloroform results in solid fibers that are 4 (± 2.0) micrometers (μm) in diameter. The porous fiber scaffolds are fabricated using a 50% weight of PCL compared to volume of solvent (w/v) solution prepared in a mixture of solvents 9:1 dichloromethane (DCM):dimethyl sulfoxide (DMSO) and 60% w/v PCL in 8:2 DCM:DMSO. The porous fibers are collected at 0-5 oC with a pore size of 50.0 (± 10.0) nanmoeters (nm) and fiber diameter of 3.0 (± 1.0) μm. The porosity for 50% w/v PCL and 60% w/v PCL fibers ranges from 40-50%.
Fiber surface morphology is characterized using field emission scanning electron microscopy (FESEM). In addition, the melting temperature and percent crystallinity are determined via differential scanning calorimetry (DSC). The melting temperature was collected of PCL bulk, 30%w/w PCL solid fibers, 50% w/v PCL and 60% w/v PCL. The crystallinity of PCL in solid fiber and porous fiber forms ranges from 52-55%, compared to the 60% crystallinity of PCL bulk. Solid PCL fibers showed to be more crystalline compared to porous PCL fibers, which in turn can effect the degradation time.
In order for these composites to be identified as a major technological advancement, the aging and degradation of the polymer scaffold must also be understood. The degradation of a given polymer matrix impacts the potential drug delivery behavior when testing in vitro. Degradation studies of the above mentioned materials are currently ongoing.

(Poster is private)

CHEM2018VILLEGAS47591 CHEM

The Anomalous Stabilization of the Cis-2-Butenyl Anion by both Through-Space and Through-Bond Interactions

Type: Undergraduate
Author(s): Hector Villegas Chemistry & Biochemistry
Advisor(s): Benjamin Janesko Chemistry & Biochemistry
Location: Session: 2; 3rd Floor; Table Number: 8

poster location

While cis/Z-substituted alkenes are usually less stable than their trans/E-substituted counterparts, the cis-2-butenyl anion shows a higher preference over the trans-isomer. Calculations suggest that the discrepancy is due to two cooperating effects: electrostatic interactions between the anionic center (C1) to the methyl group (C4) and coupling between the C=C pi* antibonding orbital and both the CH2 pz and CH3 C-H sigma bonds. Supporting the charge transfer is the fact that substitution on C1 with EDG stabilizes the cis more while substitution on C4 with EWG stabilizes the cis more. For the coupling interaction the C=C bond was stretched which increased the cis stabilization by lowering the pi* orbital energy and increasing the coupling between the lone pair on C1 and pi*.

(Poster is private)

COSC2018COX17551 COSC

RAFTER: Software for the Geological Analysis of River Stream Data

Type: Undergraduate
Author(s): Connor Cox Computer Science Kaitlin Hendrick Computer Science Kiet Nguyen Computer Science Jim Pfluger Computer Science
Advisor(s): Lisa Ball Computer Science
Location: Session: 2; 2nd Floor; Table Number: 2

poster location

Geology is better known for work done in the field than software applications, but by combining software with science, researchers can acquire results more efficiently and make better determinations about data. Stream input data, which consists of variables like stream size, depth, and sediment density, can be used to predict the location of oil deposits. Without a software application to automate the process, this is difficult to calculate manually.
This application will provide a useful resource and tool by which researchers can input geological data and have results returned based on that input. Specifically, users will enter data about streams and select one of two primary methods of calculation which will return results that refine sediment discharge estimates and give the user the yearly averaged bankfull flow duration. To achieve this we have implemented a database to store all of the necessary information concerning the stream data, such as location, climate ID, and Koeppen classification, established software to function as middleware between the database and the user interface, and built a web application that can be readily accessed online. With no knowledge of the middleware or database, the expected user can simply go on the website, select the desired method of calculation, and have the data returned to them in an easily understandable format.

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COSC2018GONZALEZ13220 COSC

Naturally Curly Cook Baking Application

Type: Undergraduate
Author(s): Rebecca Gonzalez Computer Science Daniel Fletcher Computer Science Ford McDonald Computer Science Luke Reddick Computer Science
Advisor(s): Lisa Ball Computer Science
Location: Session: 1; Basement; Table Number: 11

poster location

Naturally Curly Cook is a baking business that does catering, standing coffee shop orders, and Farmer’s Markets. Currently, Naturally Curly Cook is having difficulty with its current pen and paper ordering system and inefficient invoicing. The purpose of the Naturally Curly Cook Team is to create an iOS application that streamlines ordering and invoicing. The application will display a daily baking list and what the bakers must bake with a check box system to ensure everything has been baked. It will also display weekly orders. Orders can be added, edited, and deleted while still maintaining the orders that do not change week to week. Excel will act as the database for all customers, orders and quantities to be stored. In addition to the ordering process, an invoicing process will allow invoices to be automatically generated from the week’s orders. The new invoicing process will be generated from Excel and will allow for different pricing options and it will update with week to week changes. The intent of this project is to create a more automatic and efficient business while cutting costs and most importantly retaining data integrity.

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COSC2018HENDRICK21849 COSC

Analysis of Artificial Intelligence Techniques for Konane

Type: Undergraduate
Author(s): Kaitlin Hendrick Computer Science
Advisor(s): Michael Scherger Computer Science
Location: Session: 2; 2nd Floor; Table Number: 6

poster location

This research analyzes artificial intelligence techniques for Konane. The game Konane, also known as Hawaiian checkers, is a two-player, zero-sum strategy board game ideally suited for this research. The game ends when a player does not have a move in which they can capture an opponent’s piece. In order to have a successful strategy, a player must consider many future possibilities. For this reason, this project compares computing agents that use informed and uninformed searching algorithms. We focus our investigation on the effectiveness of the minimax and minimax with alpha-beta pruning algorithms. By altering several variables, specifically the cutoff depth for searching the game tree, we begin to see varying levels of success from the competing computing agents. The outcome of this research will be an analysis of the effectiveness of each computing agent. One of our evaluation metrics will be games statistics, such as ratio of wins to losses, time to win, and how many pieces lost.

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