Chemistry and Chemical Engineering.
Exhibition Hall C
9:45 NUMERICAL SIMULATIONS OF TRANSIENT INTERFACIAL PHENOMENA IN MISCIBLE FLUIDS
Nick Bessonov (1), John A. Pojman (2) *, and Vitaly Volpert (1), University Lyon I (1), Villeurbanne Cedex, France, and University of Southern Mississippi (2), Hattiesburg, MS 39406
To study theoretically interfacial phenomena in miscible fluids, we consider a continuous medium with a composition gradient. We describe it with the model consisting of the heat and diffusion equations with convective terms and of the Navier-Stokes equations with an additional volume force written in the form of the Korteweg stresses arising from nonlocal interaction in the fluid. It is proportional to the square of the composition gradient with the proportionality coefficient depending on temperature. We carry out numerical simulations of this model and show that the capillary force can cause convection in the initially quiescent liquid. For physically realistic values of parameters the liquid motion, though decreasing rapidly in time, can be observed experimentally. We include in the model viscosity that depends on temperature and concentration. We also include mass diffusion coefficients that depend on temperature. Because concentration and temperature gradients also cause buoyancy-induced convection, ex periments must be performed in weightlessness. Therefore, long term, high quality weightlessness is required to test the predictions of the modeling, and we propose a photopolymerization system to create the concentration and temperature gradients. Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS) is the experiment planned for the ISS.
10:00 INVESTIGATION INTO SUBTLE CHARACTERISTICS OF GLUTATHIONE AND OTHER SULFAHYDRIL AMINO ACIDS BY HIGH PRESSURE LIQUID CHROMATOGRAPHY (HPLC)
Mudlagii B. Goli *, Deepa M. Goli, and Jonathan Freedman, Mississippi Valley State University, Itta Bena, MS 38941; Southern Testing Research Laboratories, Wilson, NC; and Duke University, Durham, NC 27708
Glutathione (g-GSH) a tripeptide plays a crucial role in the biological functions. The two methods available to quantify GSH and its oxidized product GSSG are plate reader and HPLC. The reported general extraction methods consist of extracting the compounds from tissue or the cell culture followed by getting the sample ready for analysis. This paper has aimed at looking into the HPLC characteristics of the g-GSH (tri peptide) and its other two sulfahydril components g-glutamic cysteine (dipeptide) and cysteine (Cys) on the column. These three compounds have couple of COOH, carboxylic groups with very low pKa (~1.92-3.59) along with a one basic [NH.sub.2] group (pka ~8.75) that play a crucial role in derivatisation and in final analytical schemes. In fluorescent detection schemes, the derivative of SH, sulfahydril group is usually done with compounds like mono bromo bimane (MBB) or mono chloro bimane (MCB) in basic medium (pH ~8.0) followed by studying the final products either after acidifying like by using 5% SSA or in basic medium. Irrespective of the final method of analysis, the plate reader or HPLC what really matters is what are we specifically measuring and what form of the compound out of the maximum possible three forms one is looking at. The attempt is made to answer these questions by using a new versatile HPLC method. With respect to reaction of peptides with MBB or MCB, it is our observation that it is important to add enough of a water soluble organic solvent like acetonitrile ([CH.sub.3]CN) in aqueous system The reaction is also best carried out in a fairly basic medium pH of ~8.0.
10:15 USING SPINNING DROP TENSIOMETRY TO DETERMINE THE SQUARE GRADIENT PARAMETER FOR DODECYL ACRYLATE/POLY (DODECYL ACRYLATE) FOR USE IN THE TIPMPS FLIGHT INVESTIGATION
Brian Zoltowski * and John A. Pojman, University of Southern Mississippi, Hattiesburg, MS 39406
Two techniques were used to estimate the square gradient parameter for a dodecyl acrylate, poly (dodecyl acrylate) system. Using spinning drop tensiometry an effective interfacial tension (EIT) of 0.08 [+ or -] 0.01 mN/m was measured. The corresponding transition zone width was determined to be 0.10 mm, yielding a square gradient parameter of [5.sup.-8] x [10.sup.-9] N. A numerical approach using various thermodynamic theories coupled with concepts from light scattering yielded a molecular weight dependent square gradient parameter. The resulting values were shown to fall within the range of 10-11-2.5 x [10.sup.-9] N for MW's of [10.sup.4]-[10.sup.6].
10:30 MONO AND BICHROMOPHORIC COMPOUNDS FOR MODELING THE PERTURBED ELECTRONIC SPECTRA OF LIQUID CRYSTALLINE POLYMERS
David Creed (1)*, Rabih A1-Kaysi (1), Alline M. Somlai (1), Edward J. Valente (2), and Stephanie Dearmon (3), (1)University of Southern Mississippi, Hattiesburg, MS 39406; (2) Mississippi College, Clinton, MS 39058; and (3) University of Mobile, Mobile, AL 36663
UV-Vis spectra of pure films of liquid crystalline polymers (LCP) are almost invariably perturbed relative to those of simple model compounds in solution. A simple model compound (4'-pentyloxyphenyl)-4-pentyloxy cinnamate dispersed at high loadings in a polymer matrix shows an almost identical UV-Vis spectrum to an LCP with the same chromophore. A single crystal X-ray study of this model reveals the aryl ester group is twisted out of the plane of the cinnamoyl group. This supports our earlier conclusion that chromophore aggregation, not chromophore twisting, leads to the perturbed spectra of the LCP. The spectra of alkyl 4-alkoxyphenyl cinnamates are almost identical in solution to those of the analogous aryl esters suggesting the aryl esters are twisted even in solution. Several model compounds with covalently linked aryl cinnamate chromophores have been synthesized to explore the arrangement of chromophores in the LCP aggregates. Several of these bichromophoric models also show perturbed UV-Vis spectra but these spectra are unlike those seen from the LCP.
11:00 SEPARATION OF BACTERIA UTILIZING CAPILLARY ELECTROPHORESIS
Timothy Ward *, Daisy-Malloy Hamburg, Stacy Ponder, Geoffrey Stone, Bryant Jones, David Smith, and Robert Nevins, Millsaps College, Jackson, MS 39120
Identifying and quantitating bacteria and other microorganisms is a difficult problem that is becoming increasingly important. The traditional method for characterizing microorganisms is by isolation of pure cultures. Compounding this problem is the fact that sample analysis is slow, thus limiting the number of samples that can be analyzed in a given time. At the present time, there are no reliable and easy to perform techniques for separating and identifying intact microorganisms. Recently, a number of groups have explored the possibility of applying the technique of capillary electrophoresis in order to separate intact microorganisms such as bacteria and viruses. The application of this technique to this particular field of study would be advantageous, because it allows the bacteria to remain intact while being analyzed quickly and efficiently with broad applicability. In general, microorganisms tend to be amphoteric, containing multiple charges thus ideally suiting them for analysis by electrophoresis. We will present a number of examples of separation via capillary electrophoresis and discuss the relevant characteristics associated with microorganisms that must be carefully controlled before a practical and useful separation can be achieved.
11:15 CONCENTRATED ACID HYDROLYSIS OF SOFTWOOD
Wing Lian * and Roger D. Hester, University of Southern Mississippi, Hattiesburg, MS 39406
The conversion of softwood to glucose and its oligomers is optimized for a co-rotating twin screw extruder. The study identifies how each design factor affects the impregnation system and its effect on the conversion of cellulose. Conversion of cellulose is directly proportional to temperature, screw speed, back pressure, and acid concentration. The acid to solids ratio exhibits a critical point at 0.95. The ability to operate the twin screw extruder depends on the material viscosity and torque which can be controlled by adjusting material temperature, screw speed, and exit die flow restriction.
11:30 THE IMPACT OF NONIONIC SURFACTANT HYDROPHOBE STRUCTURE AND LIPOPHILIC LINKERS ON STYRENE ADSOLUBILIZATION
Yongqiang Tan * and John O'Haver, University of Mississippi, University, MS 38677
Adsolubilization, solubilization of sparingly soluble compounds in adsorbed surfactant aggregates has demonstrated applications in many fields including composite materials, pharmaceutics, and separation processes. The absolubilization of styrene by different nonionic surfactants, polyethyoxylated aikylphenols (Triton X-series) and polyoxyethylene lauryl (BRIJ-series) on amorphous precipitated silica was investigated. The effects of added lipophilic linkers (long chain linear alcohols) on the adsolubilization was examined also. The adsolubilization isotherms of surfactants with various structures were compared. The results show that at concentrations below the critical micelle concentration (CMC), adsolubilization decreased with increasing numbers of ethyoxylated (EO) groups, especially at higher styrene feed levels. The adsolubilization of styrene increased with increasing the lipophilic linkers concentration. The adsolubilization isotherm can be expressed by Langmuir-type isotherm. A basic model of adsolubi lization is provided. It is clear that lipophilic linkers can increase the solubilizing capacity of the adsorbed surfactant aggregates to some degree by increasing the interaction between the styrene and the hydrophobic group of the surfactants.
11:45 THE MUTAGENESIS OF ALPHA BUNGAROTOXIN TO FACILITATE THE CLEAVAGE OF A POLYHISTIDINE PURIFICATION TAG
Kristin S. Fairley (1*), Philip Caffery (2), and Edward Hawroot (2), (1) Tougaloo College, Tougaloo, MS 39174, and (2) Brown University, Providence, RI 02912
Alpha Bungarotoxin (alpha-Bgtx) is an essentially irreversible antagonist of the Nicotinic Acetylcholine receptor (nAChR). The discovery of alpha-Bgtx has been of great importance to the Pharmacological community in the understanding of neurotransmitter receptors. Since its isolation alpha-Bgtx has been widely used in the experimental characterization of the nAChR. Because of its great pharmacological importance, a-Bgtx has been used in labs worldwide. In order to investigate the molecular basis of its binding, alpha-Bgtx can be mutated at the amino acid level. To achieve this, the protein must be expressed recombinantly. The Hawrot Lab, at Brown University, has been able to successfully resynthesize recombinant alpha-Bgtx in E. coli. Alpha-Bgtx is recombinantly expressed in an unfolded form and is biologically inactive. To recover its full activity after refolding, the polyhistidine tag, originally attached to purify alpha-Bgtx, needs to be removed. However, the enterokinase cleavage site is only partially a ccessible to the enzyme. Causing incomplete cleavage of the His-tag. The goal of this project is to insert four glycines between the gene encoding a-Bgtx and the polyhisitidine tag, with the hopes of moving the enterokinase sight away from the protein, giving the enzyme better access to the cleavage sight. If this project is successful, it will be a great step in finally obtaining a biologically active form of recombinant alpha-Bgtx in high yields.
Exhibition Hall C
1:30 ADSOLUBILIZATION OF STYRENE BY CETYLTRIMETHYLAMMONIUM BROMIDE ADMICELLES AT WATER/MICA INTERFACES
Chun Hwa See* and John O'Haver, University of Mississippi, University, MS 38677
Tapping Mode Atomic Force Microscopy was used to study the dependence in the morphology of the polystyrene thin film formed by polymerization of styrene solubilized in adsorbed surfactant aggregates on silica. The impact of varying feed concentrations of styrene and surfactant were examined. On polished silica discs, a homogenous thin film forms at high styrene concentrations while polymer droplets were observed at low concentration of monomer. To examine the reason for these changes we have investigated the pre-polymerization surfactant/monomer aggregation behavior by soft contact mode AFM imaging in water. In soft contact mode, the tip scans the adsorbed aggregate interface by detecting the electrostatic repulsive interaction between the charge interface and silicon nitride tip. The results show that in the absence of the adsolubilized styrene, adsorbed cetyltrimethylammonium bromide (CTAB) forms rod-like adsorbed micelles with a thickness close to that of two fully-extended CTAB molecules. With increasing styrene concentration, the morphology of the adsorbed phase changes from patchy rod-like structures to a lamellar phase and finally to disk-like droplets at high styrene concentrations. Funding for this project was partially provided by National Science Foundation grant 9724187 and funding from the University of Mississippi.
1:45 AN ANALYSIS OF THE EFFECTS OF TIRE RESIDUAL ON WATER UNDER DIFFERENT pH CONDITIONS
Amanda C. Winters* and David L. Wertz, University of Southern Mississippi, Hattiesburg, MS 39406
The landfilling of scrap tires has been a prominent and controversial practice in Mississippi (and in other states) for a number of years. Little conclusive evidence exists regarding the potentially harmful environmental effects of depositing scrap tires in landfills. In conjunction with its continuing development of alternative uses for tire materials, the Wertz lab at the University of Southern Mississippi is testing the effects of tire residual--shredded tire with exposed metal wire-on water under different pH conditions. Identical amounts of tire residual were submerged in large beakers containing unmodified tap water, tap water treated with nitric acid, and tap water treated with potassium hydroxide, respectively. These experimental conditions were intended to roughly simulate possible conditions under which groundwater could be exposed to the tires in landfills. A control beaker containing only tap water was also set up. After approximately one month, the contents were filtered, dried, and analyzed with both an x-ray fluorescence spectrometer and an x-ray diffractometer. The former instrument was used to identify individual elements in the samples; the latter was used to identify the compounds formed from these elements. Preliminary analysis has revealed only iron oxides in the residue from the beakers. More analyses will be performed.
2:00 THE EFFECTS OF SUBSTRATE POLARITY AND STRUCTURE ON THE REGIOCHEMISTRY OF THE SINGLET OXYGEN ENE REACTIONS OF a, [beta]-UNSATURATED CARBOXYLATE SALTS
Anisha Bajaj* and Kristina L. Stensaas, Millsaps College, Jackson, MS 39210
Photooxidations of angelic acid salt (1), tiglic acid salt (2), 2,3-dimethyl-2-butenoic acid salt (3), and 3-ethoxycarbonyl-5,6-dihydro-2-methyl-4H-pyrane acid salt (4) were conducted in deuterated water ([D.sub.2]O). A deuterated solvent was chosen in order to increase the lifetime of singlet oxygen in solution thus decreasing reaction times. In each reaction, proton nuclear magnetic resonance spectroscopy was utilized to monitor the product distributions. The results indicate that the dominant factor in dictating the regiochemistry of the ene product is the polarity of the salt and the subsequent strong hydrogen bond that is formed between the salt and [D.sub.2]O.
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2:15 RECOVERY OF LEAD FROM SPIKED SOILS
William C. Mahone* and Tammy Johnson, Mississippi Valley State University, Itta Bena, MS 38941
Environmental contamination with lead has been identified as a serious public health problem. Soil has been identified as one of the six major sources of lead. To test or to perform remediation procedures on soil contaminated with lead, or any other heavy metals, a way to efficiently and reproducibly remove lead from the soil matrix must be found. In the current research effort to be discussed, two methods of removing lead from soil are investigated. Soil samples were spiked, then extracted using an appropriate extraction matrix. The following research focused on nitric acid and ethylene-diamine solutions as the removal matrix. Spikes and extractions were performed in triplicate in order to check the reproducibility of the process. Based on the stock standards concentration and injection volume, we used our data to calculate backwards to the amount of lead injected. This was in effect a recovery parameter. We experienced percent recoveries that ranged from 70 to 95%. We were encouraged by these results consid ering the small amounts of spike involved. The results of our investigation and the implications for analysis and remediation will be discussed.
2:30 MODELING OF THE PHOTOPOLYMERIZATION KINETICS OF DODECYL ACRYLATE
William J. Ainsworth*, John A. Pojman, Yuri A. Chekanov, and Victor T. Wyatt, University of Southern Mississippi, Hattiesburg, MS 39406
Using estimates of the rate constants for the free radical photopolymerization of dodecyl acrylate (lauryl acrylate), a kinetic model has been developed to predict the temperature and conversion behavior for use in the TIPMPS flight investigation. Isothermal photo-DSC was used to estimate the polymerization constants for use in the model. Using Arrhenius reaction kinetics we have found that this model provides rather accurate predictions for the temperature and conversion in the course of the adiabatic polymerization reaction.
3:00 INVESTIGATION OF GAS SCRUBBING DURING THE PROCESSING OF SCRAP TIRE RESIDUAL BY MEANS OF THE WERTZ OXIDATIVE METHOD
A. Giselle Schnaubelt* and David L. Wertz, University of Southern Mississippi, Hattiesburg, MS 39406
Due to the large inventory of scrap tires generated worldwide, the development of environmentally friendly methods of dealing with scrap tires has become an important issue. Scrap tires are also a reservoir of potentially valuable materials. Tire shredders can mechanically separate the rubber sidewall from other tire components--many useful recycling applications for pure tire rubber are well known. However, the remaining tire material, known as "residual," consisting primarily of steel wire and synthetic fibers that are still strongly bonded to rubber scraps, is extremely difficult to separate into useful components. The goal of this project is the implementation of the Wertz oxidative method for processing scrap tire residual on a pilot plant scale, to demonstrate that it is both environmentally friendly and economically viable. The technology is designed to convert scrap tire residual into marketable products, without generating noxious waste. Separation of the scrap tire residual into components is achiev ed by the oxidative breaking of metal-sulfur bonds and sulfur bonds within the rubber matrix. During the process, NOx gas is formed. Laboratory-scale scrubbing of this gas by absorption in potassium hydroxide solution w as evaluated for effectiveness. The influence of KOH concentration, gas dispersion, and scrubber geometry were investigated. It was determined that the method can be effective, and recommendations for larger-scale scrubber design were made.
3:15 STIMULI RESPONSIVE POLYMERS FOR ENHANCED OIL RECOVERY
Todd Rushing * and Roger D. Hester, University of Southern Mississippi, Hattiesburg, MS 39406
Petroleum is forced out of underground porous rock formations by flooding the reservoir with water. Dissolving small amounts of polymer in the water can enhance petroleum recovery by increasing the viscosity of the flooding fluid. The efficiency of the technique depends on the amount of polymer added versus the increase in petroleum recovery. The polymer additive must perform efficiently in the underground environment. Polymer molecules can be designed so that environmental conditions (i.e.; temperature, salt content, and pH) serve as stimuli to impart desired changes in solution properties. Polymer solution properties have been theoretically modeled and experimentally measured to better understand the relationship between molecular conformation and solution behavior.
3:30 pH FRONTS IN MICROEMULSIONS
Kayce Leard *, John A. Pojman, William J. Ainsworth, and Brian Zoltowski, University of Southern Mississippi, Hattiesburg, MS 39406
The focus of this investigation was to determine how the velocity and pattern of various pH front systems were affected by preparing the solutions as microemulsions. Previously investigated systems, such as the bromate-sulfite and chlorite-sulfite systems, were used in these experiments. The pure front velocities were confirmed by eliminating convection through increased viscosity or decreased tube diameter. Front velocity as a function of droplet size was then studied by preparing solutions as microemulsions. Preliminary results indicated that the velocity of the system in a microemulsion was significantly slower than the velocity in the pure system. In another set of experiments, a multifunctional acrylate, 1 ,6-hexanediol diacrylate, was added to the microemulsion solution and the pH front was initiated. Observations suggested that the pH front initiated polymerization of the acrylate during front propagation, thus acting as an initiator in the system.
3:45 MEASURING VISCOSITY VIA FLUORESCENCE DURING THE ADIABATIC, NEAT PHOTOPOLYMERIZATION OF DODECYL ACRYLATE
Victor T. Wyatt (1)*, Patrick H. Buton (2), Kayce Leard (1), and John A. Pojman (1), (1) University of Southern Mississippi, Hattiesburg, MS 39406, and (2) William Jewell College, College Liberty, MO 64068
This work is as a part of a series of experiments designed to address several areas of interest in polymer research about miscible and immiscible fluids and the stresses that influence the properties of these fluids. Eventually photopolymerization reactions are to be performed aboard the International Space Station. Photopolymerization reactions possess the ability to form a sharp concentration gradient between the monomer and the polymer being formed. During the photopolymerization reactions, measuring the viscosity of the polymer is necessary in order to compare the experimental results to fluid mechanical calculations. Therefore, the experiments require a method for determining the viscosity of the polymers during the polymerization reaction. For years, scientists have used fluorescence probes to monitor the temperature, polarity and viscosity of a system. These probes are ideal because their emissions are sensitive to changes in their local environment. Examples of such behavior are shown in probes whose intensity increases upon polymerization or during other rigidification processes such as physical aging. In our studies, pyrene and bis-pyrene have been used as molecular probes to non-invasively monitor viscosity during the polymerization of dodecyl acrylate. Fluorescence and viscosity correlation measurements were performed as a function of concentration and temperature for polymers of two different molecular weights.
4:00 INVESTIGATION OF THE THERMAL AND MECHANICAL PROPERTIES OF NOVEL GLASS AND CARBON FIBER-REINFORCED THIOL-ENE COMPOSITES
Kalena D. Stovall *, Charles E. Hoyle, Eric P. Taylor, and Joshua U. Otaigbe, University of Southern Mississippi, Hattiesburg, MS 39406
The thermal and mechanical properties of pure thiol-ene resins, and their composites with glass and carbon fiber mats were explored. The composites were prepared by soaking the fiber mats in the resins, and photopolymerizing the systems under UV light. The thermal and mechanical properties of the composite systems were examined as a function of the glass or carbon fiber content. The results showed an increase in the stiffness and strength of the composites with increasing volume concentrations of the glass and carbon fibers.
Exhibition Hall C
9:30 MEASURING THE DIFFUSION COEFFICIENT FOR DODECYL ACRYLATE/POLY (DODECYL ACRYLATE) USING LASER LINE DEFLECTION
Charles Edwards *, Lydia Lee Lewis, and John A. Pojman, University of Mississippi, University, MS 38677; Millsaps College, Jackson, MS 39120; and University of Southern Mississippi, Hattiesburg, MS 39406
The coefficient of diffusion for a dodecyl acrylate/poly dodecyl acrylate system was measured as a function of concentration, molecular weight, and temperature using laser line deflection. As monomer and polymer diffuse, a concentration gradient forms. A line laser passing through this gradient is bent. By projecting this onto a screen, recording as a function of time, the coefficient of diffusion as a function of time and concentration can be extracted.
9:45 CONTROLLED INITIATION OF FRONTAL POLYMERIZATION USING MICROENCAPSULATION TECHNIQUES
Brian McFarland * and John A. Pojman, University of Southern Mississippi, Hattiesburg, MS 39406
In frontal polymerization, a monomer is converted into a polymer by thermal initiation through a self-sustaining front of propagation. One innate problem with frontal polymerization is that the front temperature can be so high that foaming can occur, disrupting the system. This problem may be addressed by dilution of the monomer, but too much dilution can result in a front temperature too low to self-sustain. Another problem is that frontal polymerization systems often have a short pot life as a result of decomposition of the initiator. As a result, the components of the system must be stored separately until the desired time of the reaction. A possible solution to both of these problems is microencapsulation. Microencapsulation allows a component of the system to be separated from the other components by means of trapping it in a chemical shell or coating. By using a microencapsulated initiator in conjunction with the proper redox accelerator, it may be possible to achieve low-temperature fronts that are sus tainable in dilute monomer. The microcapsules may also provide an advantage in storage/pot life as well, as the components of the frontal polymerization system could be stored together for a period of time without the initiator coming in contact with the rest of the system. The effectiveness of different methods of microencapsulation that are used in this application is studied, as well as different release methods and shell materials.
10:00 INVESTIGATION OF THE THERMAL AND MECHANICAL PROPERTIES AND POLYMERIZATION RATE OF HOMOPOLYMER AND COPOLYMERLYOTROPIC LIQUID CRYSTAL SYSTEMS
Kalena D. Stovall *, Demetrius T. McCormick, and C. Allan Guymon, University of Southern Mississippi, Hattiesburg, MS 39406
This study focuses on the synthesis of homopolymer and copolymer hydrogels via the photopolymerization of water-soluble and oil-soluble monomers in Pluronic Lyotropic Liquid Crystals (LLCs). In particular, the mesophase thermal stability, polymerization kinetics, and physical properties have been examined. Mesophase thermal stability was enhanced in each of the polymer/Pluronic composites compared to the parent LLC mesophase. The mesophase thermal stability varied significantly with differences in polymer nanostructure and, in some cases, copolymer content. The compressive modulus of the polymer hydrogels also depends heavily on the polymer nanostructure evolved and copolymer content. Higher polymerization rates were observed in the inverse phases for the water-soluble monomer and in normal phases for the oil-soluble monomer.
10:15 ISOTHERMAL FRONTAL POLYMERIZATION: LIMITATIONS AND COMPARISON OF FRONT CHARACTERISTICS
Lydia Lee Lewis * and John A. Pojman, Millsaps College, Jackson, MS 39120, and University of Southern Mississippi, Hattiesburg, MS 39406
Isothermal Frontal Polymerization (IFP) is a directional polymerization that occurs when monomer and thermal initiator diffuse into a polymer creating a viscous region. The rate of polymerization in this viscous region is higher than in solution of monomer and thermal initiator because of the Trommsdorff, or gel, effect, resulting in a propagating front. To better understand how various parameters affect IFP, systems of the monomer [right arrow] polymer system of methyl methacrylate [right arrow] poly(methyl methacrylate) were examined using poly(methyl methacrylate) seeds and the thermal initiator 2,2'-azobisisobutyrolnitrile. These systems were run at various initiator concentrations and temperature ranges to compare propagation distances and velocities. These times and velocities increased with increasing initiator concentration and/or temperature up to the limit of 0.03% initiator concentration (wt./V) at the temperature of 87[degrees]C. At these conditions, bulk polymerization of the monomer solution pro hibited frontal polymerization. This concentration limit increased with decreasing temperature until it was discovered that propagation occurred for saturated solutions at temperatures below 50[degrees]C. For the conditions at which IFP occurred, the propagation distance was 0.6 [+ or -] 0.15 cm regardless of initiator concentration and cure temperature.
11:00 Divisional Poster Session
AN INVESTIGATION OF MONOMER TRANSPORT IN EMULSION POLYMERIZATION UTILIZING HYDROPHOBIC ACRYLIC MONOMERS
Mary Rogers Moore *, C. Todd Williams, and Shelby F. Thames, University of Southern Mississippi, Hattiesburg, MS 39406
Investigations into the emulsion polymerization of hydrophobic acrylic monomers, n-decyl to octadecyl acrylate/methacrylate, at ten weight percent have determined whether these monomers can be copolymerized into latex polymers. It was hypothesized that changing the shear rate during the pre-emulsion dispersion from 1,800 revolutions per minute (rpm) to 18,000 rpm would produce smaller monomer droplets as well as increase the number of monomer droplets within the system. This variation posed a strong possibility of polymerization occurring in both the micelles and the monomer droplets. Each monomer was characterized using reversed-phase high performance liquid chromatography. The resulting latex polymers were evaluated for particle size, polymer composition and thermal transitions. The evaluations confirmed that it is possible to incorporate hydrophobic acrylic monomers into latex polymers through this experimental method. Some of the resulting latex polymers contained crystalline domains indicating that a por tion of the monomer was not sufficiently interacting to form random copolymers.
THE DEVELOPMENT OF LASER LINE DEFLECTION TO MONITOR POLYMER FRONTS
Lydia Lee Lewis (1), Alford Perryman (2) *, and John A. Pojman (2), (1) Millsaps College, Jackson, MS 39120, and (2) University of Southern Mississippi, Hattiesburg, MS 39206
Propagating isothermal fronts contain vertical gradients (changes) in the concentrations of their components and thus, contain refractive index gradients. These gradients correspond to the region containing the reacting front, are on the order one centimeter to less than one millimeter, and are visibly indiscernable from the unreactive system. A technique has been developed to discern these small changes in refractive index using the theory of light deflection where incident light normal to the surface of interest is deflected by a change in refractive index. A five milliwatt line laser was used to monitor the isothermal frontal system of methyl methacrylate providing the most accurate data to date for isothermal frontal propagation. The experimental apparatus and the analysis method are discussed as well as their limitations, advantages, and experimental and analytical error.
DETERMINATION OF COAL STRUCTURE UTILIZING WIDE ANGLE X-RAY SCATTERING: EFFECTS OF SOLVENT SWELLING
Matt Myers * and David L. Wertz, Delta State University, Cleveland, MS 38733, and University of Southern Mississippi, Hattiesburg, MS 39406
Wyodak-Anderson coal, a sub-bituminous coal, has been shown to swell in the presence of certain organic liquids, and even retain its swollen state after the liquid has evaporated. Seven different liquids were used in this study. Molecular-level structural models show interplaner distance between the polycyclic units of ca. 3.6 A for Wyodak. Upon the addition of pyridine the distance increased to ca. 3.9 A. This evidence shows that, although pyridine evaporated, the coal was still affected on a macromolecular scale.
EFFECTS OF DIFFERING IRRIGATION WATER TYPES ON NITROGEN FIXATION IN RICE FIELDS
Susan Towery (1,2) * Paul V. Zimba (2), Robert Zablotowicz (2), and Charles C. Mischke (3), (1) Delta State University, Cleveland, MS 38733; (2) USDA/ARS, Stoneville, MS 38776; and (3) Mississippi State University, Stoneville, MS 38776
Little research has been published on how different water sources affect potential nitrogen fixation in Mississippi rice fields. Water samples were collected from two fields irrigated with different water sources (well water and surface water sources) and nutrient (N, P. Si) concentrations were determined. Replicate sediment samples were analyzed for algal pigments (HPLC) and for nitrogen fixation (acetylene reduction method, GC). Nutrient levels in the surface water were higher than those in the well water. The nitrogen fixation potential was spatially and temporally heterogeneous, with the rice field receiving surface water having higher nitrogen fixation rates than the field irrigated with well water. Surface waters appeared to support elevated cyanobacterial-mediated nitrogen fixation rates (63% increase in light dependant nitrogen fixation rates relative to well water irrigation). Bacterial nitrogen fixation rates were 250% higher in the field receiving well water relative to surface water irrigation. Ni trogen fixation normalized to algal biomass (chl a) was higher in the surface water irrigated field. HPLC analyses revealed the presence of clorophytes, cyanobacteria, and bacillariophytes (diatoms). The seed population from surface waters may be an important source of nitrogen fixing organisms and irrigation management should consider the source of water used in irrigation of rice fields.
LOW PRESSURE MICROCHIP CHROMATOGRAPHY DeGail Hadley (*) and Charles S. Henry, Delta State University, Cleveland, MS 38733, and Mississippi State University, Starkville, MS 39762
This presentation examines the fabrication and utilization of microchip low pressure chromatography as an alternative tool for the determination of the school virial coefficient. This methodology is faster, simpler, less expensive, and more compact than the traditional methods used to analyze protein-to-protein interaction. The capacity factor ([k.sup.1]) was studied for lysozyme in varying experimental conditions such as crystallizing agent concentration, concentration of the protein, and varying flow rates. A very good correlation between the results of the static light scattering method and the microchip low pressure chromatography method was observed. This project thus proves that self-interaction chromatography can be miniaturized to an approximate column volume of 1.778 ml.
PREPARATION AND CRYSTAL STRUCTURE OF MELAMINE LEVULINATE MONOHYDRATE
Ramaiyer Venkatraman, Jackson State University, Jackson, MS 39217
Melamine levulinate monohydrate has been prepared and structurally characterized by room temperature X-ray diffraction technique. The crystals are monoclinic, space group P2(1)/c, a 10.538(2) A, b = 16.214(3) A, c = 7.1988(14) A, [alpha]= 90[degrees], [beta] = 95.85(3)[degrees], [gamma] = 90[degrees]., V = 1223.6(4) A (3), Z = 4. The interesting features of the intermolecular hydrogen bonding interactions occurring between melaminium amino group and ring nitrogen with the carboxylate oxygen atom of levulinic acid and as well with water molecules will be presented.
PURIFICATION OF GLUTAMINYL CYCLASE
Neil Stowe (1*), Stephanie Misquitta (2), and Robert Bateman (2), (1) Delta State University, Cleveland, MS 38733, and (2)University of Southern Mississippi, Hattiesburg, MS 39406
Glutaminyl Cyclase (QC) is an enzyme that catalyzes the conversion of N-terminal glutaminyl peptides to pyroglutamyl peptides. QC is found in plants and animals-particularly in the hypothalamus of mammals and in papaya latex. The conversion of glutaminyl peptides to pyroglutamyl peptides can occur without QC-high pH and high concentrations of phosphate ion allow for conversion, but the reaction is slow under physiological conditions, making QC a necessary enzyme. The reaction that QC catalyzes is known, and the structure of QC has been identified using bacteria and fruit flies that make QC protein from the cDNA. But, the complete structure of the native enzyme is not known. The goal of my summer research is to purify native QC (QC found in the natural cell) to allow its complete structure to be determined.
USE OF AN EXPERIMENTAL SPRAY CHAMBER TO ESTABLISH SPRAY CHARACTERISTICS OF HERBICIDES WITH ANALYSIS BY AA
April Robinson (1*), Jason Corbitt (1), Andrew Steele (1), Marcus Steele (1), Phelesia Foster (2), Dennis Elmore (2), and Lowrey Smith (2), (1) Delta State University, Cleveland, MS 38733, and (2) United States Department of Agriculture, Agricultural Research Services, Stoneville, MS 38776
The Environmental Protection Agency and Mississippi Department Environmental Quality severely regulate the aerial application of two herbicides, glyphosate and glufosinate, due to potential damage to non-glyphosate resistant cotton and soybeans and non-glufosinate resistant rice and corn. This study examines the spray rate and herbicide spray composition to optimize the deposition of the herbicides and a tracer, rubidium, as they are applied in an experimental spray chamber Spray droplets were collected at selected sampling sites on flat Mylar sheets, drinking straws, and cotton strings. The droplets were removed from each of these collection devices using HPLC grade ethanol or reverse osmosis water. Subsequently, the extracts were analyzed for tracer, Rb, by a Perkin Elmer 5000Z electrothermal atomic absorption spectrophotometer. A grid of the spray area and the effects of spray rate and composition will be presented.
AN INVESTIGATION OF THE EMULSIFYING CAPABILITES OF AMPHIPATHIC TITANIUM DIOXIDE PARTICLES
Shelly R. Gallender (*) and Robert Y. Lochhead, University of Southern Mississippi, Hattiesburg, MS 39406
The stabilization of emulsions by small amphipathic particles is of interest to cosmetic companies because it allows the use of surfactants to be reduced or eliminated in their products. Surfactants can interact with the skin to cause irritation that can be eliminated by the use of particle stabilized emulsions. US Patent 6440399 claims that titanium dioxide particles coated with alumina and dimethicone and having an average particle size of less than 200 nm stabilize emulsions by arranging themselves at the oil-water interface, thus preventing the coalescence of the dispersed phase. These particles have the trade name of Eusolex T2000 from Merck. Titanium dioxide particles are also useful in the field of cosmetics because they act as a sunblock. The claims of the patent were investigated by using ternary phase diagrams to chart the regions of emulsion stability and instability. The oils used for the phase diagrams were silicon oil, mineral oil, and caprylic/capric triglyceride.
ANALYSIS OF TOTAL SUGAR IN THE HYDROLYZATE FROM SAWDUST WITH SELIWANOFF REAGENT
Ken Lee (1), Sharon Hurley (1*), Omar Nava (2), Centeria Cornellius (1), and Esmeralda Fuentes (3), (1) Jackson State niversity, Jackson, MS 39217; (2)Socorro High School, and (3) Bracken-ridge High School
In the project to produce ethanol from the sawdust via acid-hydrolysis and fermentation, the determination of concentration of total sugar and other organic components in the hydrolyzate is necessary for optimizing the process. The analysis with HPLC, however, is a long process, which is not suitable to be used as a part of quality control in the acid-hydrolysis. Therefore we use the Seliwanoff reagent for determining of actual concentration of total sugar in the hydrolyzate. Sin ce it gives dark red color after that resorcinol reacts with 5-hydroxymethylfurfural (HMF), which is the dehydration product of sugar, the calibration line has been made from the series of known concentrations of sugar. To make the calibration line based on known concentration of sugar two different spectrophotometers, UV Spectrophotometer and Spectronic 20, were used. The calibration lines from two experiments were almost same, so Spectronic 20 can be used in the process for the quick analysis. Total concentration of sugar of the h ydrolyzate was determined from the line and 4.5% and 4.7%, which were obtained from two different experiments. This result was compared with the result, 4.2%, from the National Reusable Energy Laboratory at Golden, Colorado, using HPLC. This project is supported by DOE EPSCOR, Grant #DE-FG0200ER45830, NASA Summer High School Apprenticeship Research Program (SHARP) Plus Program, and Science and Technology Access to Research Graduate Education (STARGE) from NSF.
ANALYSIS OF SUGARS AND ORGANIC ACIDS IN HYDROLYZATE FROM SAWDUST BY HPLC
Ken Lee (1*), Ruiz Raymond (2), and Bonnie Hames (2), (1) Jackson State University, Jackson, MS 39217, and (2) National Reusable Energy Laboratory, Golden, CO 80401
Four different hydrolyzates, the product of acid hydrolysis of sawdust, were analyzed by the method, which National Reusable Energy Laboratory (NREL) at Golden, Colorado, has established. Two HPLC instruments having a specified column and a reflective index as a detector were used. Pretreatment on the sample like dilution, titration and filtration were performed to adjust pH before actual analysis. Actual concentrations of sugars, glucose, xylose, galactose, arabinose, and mannose and total sugar concentration after complete hydrolysis were obtained. Contents of organic acids and furfurals including 5-hydroxymethylfurfural (HMF) were analyzed in the sample. Total sugar concentration varies from 2.8% to 4.2% including aldohexoses and aldopentoses, which are written in the table below. No organic acids and furfurals except acetic acid were detected. This experiment is suitable for analyzing the sugar contents as well as organic acids in the hydrolyzates from sawdust.
Sugar contents in the hydrolyzate (mg/ml) before second hydrolysis Sample Glucose Xylose Galactose Arabinose Mannose Total Number Sugar A 26.65 4.48 2.78 1.40 6.70 42.01 P 6.90 7.52 3.33 3.90 6.96 28.61 S10 14.27 4.14 3.43 0.82 10.15 32.81 S06 15.92 5.62 3.74 1.12 11.21 37.61
INVESTIGATION OF THE STRUCTURE OF POLYELECTROLYTE-BASED COMPLEX COACERVATES
Lisa Huisinga (*) and Robert Y. Lochhead, University of Southern Mississippi, Hattiesburg, MS 39406
Polyquaternium compounds are theorized to be useful in forming complex coacervates in the concentrated surfactant regime. A variety of anionic surfactants, such as sodium lauryl ether sulfate and sodium dodecyl sulfate, and cationic polymers were used to form these coacervates. The structure of the lyotropic association colloid within these complex coacervates was mapped using ternary phase diagrams. The structure of the lyotropic mesophase was identified by Polarized Light Microscopy (PLM). The concentrations of surfactant and polymer in each phase were measured using Fourier-Transform Infrared Spectroscopy (FTIR) an UV Spectroscopy. Hydrophobically modified cationic polymers were also studied with respect to the structure of the lyotropic association colloid within the complex coacervate.
PHOTOCHEMISTRY OF SELECTED NITRO-POLYCYCLIC AROMATIC HYDROCARBONS
Demarcio Reed (*), Generique Stewart, Yuguo Jiao, and Hongtao Yu, Jackson State University, Jackson, MS 39217
Nitro-substituated polycyclic aromatic hydrocarbons (nPAH) are produced either directly or indirectly from incomplete combustion of materials. It is found in automobile diesel exhaust and is linked to 30% of the mutagenicity of the exhaust gas toward Salmonella typhimurium. Upon entering the environment, nPAH are degraded biologically by bacteria or by photodegradation in the environment. The photodegradation rate of the nPAH depends on whether they are in the air, in sediment waters or in particulate matters. It has been found that the position of the nitro group is an important factor for genotoxicity. In this study of 4/5 ring nPAH have been examined for photochemical reactions in aqueous media. It is found that both the photochemical degradation kinetics and photoproducts for 7-nitrobenz[a]anthracene (7NBA), 5-methyl-7-nitrobenz[a]anthracene (5M7NBA), 12-methyl-7-nitrobenzo[a]anthracene (12M7NBA), 7-nitrodibenzo[a,h]anthracene (7NDBA), 9-nitrodibenzo[a,h]anthracene (9NDBA) depended on the position of the nitro group and the surrounding ring structure. Upon light irradiation, both 7NBA and 5M7NBA yielded the respective 7, 12-quinones, while l2M7NBA yielded multiple products including 7, 12-quinone. A detailed mechanism for the formation of respective photo-products is proposed. Acknowledgement: Th is research has been supported by generous grants NIH-SCORE S06GM08047 for research and NSF-STARGE for student support.
REAL-TIME MONITORING OF RING-OPENING BULK POLYMERIZATIONS OF A-CAPROLACTONE USING FTIR SPECTROSCOPY
Eric McClendon (*), Jamie Messman, and Robson Storey, University of Southern Mississippi, Hattiesburg, MS 39406
The bulk polymerizations of A-caprolactone (CL) were monitored via IR-spectroscopy. Each polymerization was conducted at 134[degrees]C. The initiators used were n-butanol (BuOH), ethylene glycol (EG), and 1,3-propane diol (PD). The amounts of inititiator used varied according to the molecular weight targeted. The induction periods for EG and PD were observed and support the previous findings of our group. However, here we also see an induction period with BuOH. These induction periods were due to both heat transfer and the delayed formation of the stannous alkoxide. The data was supportive of the mechanism previously proposed by Penczek. This mechanism was previously confirmed by Sherman.
CARGO DELIVERY--AN APPROACH WITH POTENTIAL FOR RADIO DIAGNOSTIC AND RADIO THERAPEUTIC AGENTS
Roshenia Johnson (l*), Fabio Gallazzi (2), Jenny Green (2), Rachel Reuther (2), Catalina Arbelaez (2), and Susan Lever (2), (1) Alcorn State University, Alcorn, MS 39096, and (2) University of Missouri-Columbia, Columbia, MO
From a biomedical stand point, permeating peptides act as carriers for radioactive isotopes, which are used in diagnosis of cancer or cancer therapy. In order for radio diagnostic and radio therapeutic peptides to enter cancer cells they must be able to pass through the cell membranes of target cells. In theory, this can be accomplished by having a disulfide bond instead of an amide bond to attach the permeating portion of the permeating peptide to the radio diagnostic and radio therapeutic agents. Two techniques for attaching Cys (Npys) to the control peptides GAYAYYA (1) and -DRRIFWWSLRSAGA (2) were tested. The first technique entailed coupling Boc-Cys (Npys)-OH using standard peptide synthesis. However, HATU was used instead of the usual HBTU. The results were analyzed via HPLC and Mass spectrometry. The results for the first technique revealed failure of the Boc-Cys (Npys) to attach to the peptides probably because Npys is not stable in HATU. The second technique entailed coupling Boc-Cys (Npys)-OH with the control peptides GAYAYYA (1) and -DRRIFWWSLRSAGA (2) with in situ activation reaction. The procedures followed for the second technique did not follow standard peptide synthesis. This reaction was synthesized manually from adding 150 mg of Boc-Cys (Npys)-OH and 110 mg of pentafluorophenol in 10 mL of dichloromethane to DCC in 10 mL of dichloromethane. The results were tested via TLC. TLC was done using a 3:1 solution of chloroform and methanol, as well as, with ethyl acetate. [Rf = 0.65 (chloroform-methanol); Rf = 0.92 (ethyl acetate)].
GC-FID ANALYSIS OF WATER SOLUBLE FRACTION OF GASOLINES
William C. Mahone (*) and Robert Clemmons, Mississippi Valley State University, Itta Bena, MS 38941
Gasoline in drinking water is a common problem resulting from wide spread use of metal underground storage tanks in previous decades. Many soil chemicals accelerate corrosion of the metal containers resulting in underground leaks. Once past the oxygen layer in the soil these chemicals follow the water trail to the underground aquifers. This mechanism has been responsible for many drinking water contamination events over the years. We have in the past developed GC-FID methods for the analysis of pure gasolines to develop fingerprint identification techniques. We are currently focused on analysis of the water-soluble fraction of various gasolines. Our efforts have focused on sampling and test preparation methods. In our current effort we use LLE and SPME to collect and pre-concentrate the water component of gasoline. The ultimate objective of our work is to develop GC-FID methods that will allow us to test for volatile and semi-volatile species in water from various sources at the concentration levels required by today's regulations. We have to date ran tests on the LLE extract and compared it to chromatograms on the diluted pure gasoline. We have ran chromatograms in on the water extract in the split and splitless modes and have collected a footprint. We believe that this footprint maybe as distinctive and the footprint for the pure sample enabling one to connect a contamination to a particular brand or refinery. The following presentation will chronicle our achievements to date.
Exhibition Hall C
1:00 Division Business Meeting and Awards
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|Title Annotation:||summary reports|
|Publication:||Journal of the Mississippi Academy of Sciences|
|Date:||Jan 1, 2003|
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