Chemistry Commons^™

Phase Change Enthalpies And Entropies Of Liquid Crystals, William Acree, James Chickos

Chemistry & Biochemistry Faculty Works

No abstract provided.

Reversible Paramagnetism To Ferromagnetism In Transition Metal-Doped Tio2 Nanocrystals Prepared By Microwave Irradiation, Garry Glaspell, Asit B. Panda, M. S. El-Shall

Chemistry Publications

TiO2nanoparticlesdoped with 1%, 5%, and 10% M (M=Co, Fe, and Ni) were prepared by microwave irradiation and characterized using x-ray diffraction, transmission electron microscopy, and magnetometry. The as-prepared samples are found to be paramagnetic at room temperature, with the magnetic susceptibility following the Curie-Weiss law in the investigated range of 2–300K. However, transformation from paramagnetism to room-temperature ferromagnetism (RTFM) was observed by hydrogenating the samples at 400°C. Reheating in air converted the samples back to paramagnetic while rehydrogenating the samples again induced ferromagnetism. It is argued that the reversible RTFM observed is due to interaction between the dopant metal ions …

Orientational Correlations In Liquid Acetone And Dimethyl Sulfoxide: A Comparative Study, Sylvia E. Mclain, Alan K. Soper, Alenka Luzar

Chemistry Publications

The structure of acetone and dimethyl sulfoxide in the liquid state is investigated using a combination of neutron diffractionmeasurements and empirical potential structure refinement (EPSR) modeling. By extracting the orientational correlations from the EPSR model, the alignment of dipoles in both fluids is identified. At short distances the dipoles or neighboring molecules are found to be in antiparallel configurations, but further out the molecules tend to be aligned predominately as head to tail in the manner of dipolar ordering. The distribution of these orientations in space around a central molecule is strongly influenced by the underlying symmetry of the central …

Optimization Of Long Range Electron Transfer For Solar Energy, Randall H. Goldsmith

Link Foundation Energy Fellowship Reports

Organic photovoltaics have the potential to become an accessible form of alternative energy production because of their ease of manufacture via traditional printing techniques and consequent low cost.1 However, the simplicity of device manufacture belies the complex cascade of processes that allow light to be efficiently converted into electrical power.2 Electron transfer (ET) events constitute the most critical steps. ET is known to be governed by a complex function of many system-specific variables including distance, orientation, and energetics of the donor and acceptor species.3

Spectroscopic Characterization Of The Ground And Low-Lying Electronic States Of Ga2n Via Anion Photoelectron Spectroscopy., S M. Sheehan, Giovanni Meloni, B F. Parsons, N Wehres, D M. Neumark

Chemistry Faculty Publications

Anion photoelectron spectra of Ga2N− were measured at photodetachment wavelengths of 416nm(2.978eV), 355nm(3.493eV), and 266nm(4.661eV). Both field-free time-of-flight and velocity-map imaging methods were used to collect the data. The field-free time-of-flight data provided better resolution of the features, while the velocity-map-imaging data provided more accurate anisotropy parameters for the peaks. Transitions from the ground electronic state of the anion to two electronic states of the neutral were observed and analyzed with the aid of electronic structure calculations and Franck-Condon simulations. The ground-state band was assigned to a transition between linear ground states of Ga2N−(XΣg+1) and Ga2N(XΣu+2), yielding the electron affinity …

The Elastic Constants And Related Properties Of The Energetic Material Cyclotrimethylene Trinitramine (Rdx) Determined By Brillouin Scattering, James J. Haycraft, Lewis L. Stevens, Craig J. Eckhardt

Craig J. Eckhardt Publications

The acoustic phonons of cyclotrimethylene trinitramine (RDX) have been studied using Brillouin scattering. The analysis of the acoustic-phonon velocities allowed determination of the complete stiffness tensor for this energetic material. The results are compared to other recent experimental and theoretical determinations of the RDX elastic constants, bulk moduli, and shear moduli. The observed ordering of elastic constants, C₁₁>C₂₂>C₃₃, is qualitatively associated with a (001) cleavage plane and molecular packing. This interpretation is further corroborated by the linear compressibilities plotted in three crystallographic planes, and a comparison to recent theoretical and experimental hydrostatic compression studies …

Spectroscopic And Thermodynamic Analysis Of Co Rebinding And Photodissociation From Fe (Ii) Lpo, Dustin Michael Lockney

Theses, Dissertations and Capstones

Lactoperoxidase (LPO) is a heme peroxidase found in tears, milk, saliva, and cervical fluids that has bactericidal activity. The bactericidal nature of LPO is due to its ability to oxidize halides and pseudohalides in the presence of H2O2. Full understanding of the catalytic cycle of LPO requires detailed characterization of the mechanism of ligand binding to the enzyme active site. This includes a dynamic and energetic description of conformational changes associated with heme-ligand interactions. Photoacoustic calorimetry is applied to determine the kinetics and magnitude of reaction volume and enthalpy changes for CO dissociation from CO-LPO. Time-resolved absorption spectroscopy was used …

Scanning Probe Microscopy And Oxidation Of Silicon At Breakdown Voltages, Thabo Gcwabaza

Theses, Dissertations and Capstones

The growing importance of Scanning Probe Microscopy (SPM) as a tool for nanofabrication is opening many avenues in lithography nano-science. One type of Scanning Probe Lithography involves electrochemistry at the tip/substrate interface. Atomic Force Microscopy (AFM) with conductive tips and substrates was used in our study to both pattern and image those patterns on silicon substrates. Our long-term objective is to design and fabricate micron-scale patterns of nanometer sized spots on silicon chips that can serve as attachment sites for DNA based nano-arrays. In order to fabricate such substrates a study of the underlying electrochemistry was required. A most promising …

Design And Implementation Strategies For Peer-Led Team Learning In Organic Chemistry, Stephen K. Manu

Capstone Research Projects

Peer-Led Team Learning (PLTL), which initially began as an effort to improve undergraduate chemistry education, has shown the potential to improve learning among college students in all disciplines. The model applies the desired qualities of teamwork to learning. This project is aimed at designing and setting up a PLTL Workshop at Southern Adventist University (SAU). Nine students currently taking organic chemistry at SAU volunteered to participate in the project. In order to determine the effectiveness of the project, test scores were collected and analyzed for any apparent trends, and an end-of-semester survey was conducted. The results indicate that the program …

Purified Water: A Closer Look At Bottled Waters And Their Claims, Henry Piñango

Capstone Research Projects

The claims made by three bottled water manufacturers were checked through a series of tests. CHA ™ (by Abundant Life CHA ™ Water Company in Chattanooga, TN), Penta ® (by Bio-hydration Research Lab, Inc.), and Mountain Fresh superoxygenated water (Collegedale, TN) were the subject of this study. Three tests were done on these samples: pH level, dissolved oxygen, and osmosis rate test. The pH level test confirmed the claim that CHA ™ water is alkaline (pH = 9.6); the other samples tested had pH levels ranging from 6.5 to 7.6. The dissolved oxygen test compared the oxygen concentration of several …

Restoration Of Frequency-Dependent Depression Of The H-Reflex By Passive Exercise In Spinal Rats, N. B. Reese, R. D. Skinner, D. Mitchell, C. C. Yates, Christina B. Cooley, T. S. Kiser, E. E. García-Rill

Chemistry Faculty Research

Hyper-reflexia, measured as a decrease of low frequency-dependent depression of the H-reflex, is known to occur in both humans and animals after spinal cord injury (SCI). Previous studies have shown that passive exercise for 3 months could be used to restore low frequency-dependent depression of the H-reflex after SCI. To determine the effects of various periods of time on the ability of passive exercise to restore low frequency-dependent depression of the H-reflex. Spinal Cord Injury Mobilization Program of the Center for Translational Neuroscience, the research arm of the Jackson T Stephens Spine and Neuroscience Institute, Little Rock, AR, USA. Adult …

Cation Occupancy Determination In Manganese Zinc Ferrites Using Fourier Transform Infrared Spectroscopy, M. D. Shultz, E. E. Carpenter, S. A. Morrison, S. Calvin

Chemistry Publications

The magnetic and electric properties of ferrites are influenced by the cation distribution within the crystalline spinel lattice. Methods such as extended x-ray-absorption fine structure(EXAFS) have been used to determine cation occupancies within the crystalline structure of materials such as manganesezincferrite (MZFO); however, it is not practical to be used for daily analysis. Fourier transform infrared (FTIR)spectroscopy is another technique which has the potential to determine cation occupancy while offering speed and convenience. In the literature it has been demonstrated that in ferrite systems FTIR data can be correlated to cation percentages when comparing tetrahedral (Td) and octahedral (Oh) sites. …

Structure And Vibrational Spectra Of Mononitrated Benzo [A] Pyrenes., Kefa Karimu Onchoke, Christopher M. Hadad, Prabir K. Dutta

Faculty Publications

The molecules benzo[a]pyrene (BaP) and 1-, 3-, and 6-nitrobenzo[a]pyrene (1-NBaP, 3-NBaP, 6-NBaP) are currently of significant interest due to their presence in respirable combustion exhaust particulates and their mutagenic and carcinogenic properties. Structure−function correlations as well as spectroscopic signatures for trace analysis are necessary for these benzo[a]pyrene derivatives. In this paper, detailed infrared and Raman spectroscopic data of BaP and its three mononitrated isomers are provided for the first time. By utilizing density functional theory (DFT, B3LYP method with 6-311+G** basis set), the molecular geometries and the vibrational spectra are calculated. Good agreement is …

A Molecular Salt Of Tricyanomethanide Anion And A N,N9- Dianisylphenazinium Dication: Cooperative Affects Of Methoxy…Methoxy And Cmn…N+ Intermolecular Contacts, Scott E. Mckay, Kraig A. Wheeler, Silas C. Blackstock

Faculty Research and Creative Activity

A molecular salt of tricyanomethanide anion and a N,N9- dianisylphenazinium dication forms extended supramolecular assemblies that consist of unusual methoxy…methoxy and CMN…N+ intermolecular contacts.

Optical Susceptibilities Of Supported Indium Tin Oxide Thin Films, Jonathan L. Humphrey, Darius Kuciauskas

Chemistry Publications

The third-order nonlinear optical susceptibility of indium tin oxide (ITO) thin films on glass substrates, χ(3)ITO, was determined in the near-IR spectral region using degenerate four wave mixing (DFWM)spectroscopy with 100fs laser pulses. A DFWM method for measuring thin films on thick substrates was refined for the characterization of films less than 100nm thick and applied to ∼25nm thick ITO films. It was found that χ(3)ITO is purely electronic at 900–1300nm (11000–7700cm−1) and has a value of (2.16±0.18)×10−18m2V−2. Theχ(3)ITO value reaches (3.36±0.28)×10−18m2V−2 at 1500nm (6700cm−1) due to two-photon absorption by free carriers (electrons). Ultrafast electron relaxation was also observed. The …

Magnetic And Mossbauer Spectroscopy Studies Of Nanocrystalline Iron Oxide Aerogels, E. E. Carpenter, J. W. Long, D. R. Rolison, M. S. Logan, K. Pettigrew, R. M. Stroud, L. Theil Kuhn, B. Rosendahl Hasen, S. Mørup

Chemistry Publications

A sol-gel synthesis was used to produce iron oxide aerogels. These nanocrystalline aerogels have a pore-solid structure similar to silica aerogels but are composed entirely of iron oxides. Mössbauer experiments and x-ray diffraction showed that the as-prepared aerogel is an amorphous or poorly crystalline iron oxide, which crystallized as a partially oxidized magnetite during heating in argon. After further heat treatment in air, the nanocrystallites are fully converted to maghemite. The particles are superparamagnetic at high temperatures, but the magnetic properties are strongly influenced by magnetic interactions between the particles at lower temperatures.

Ipro: An Iterative Computational Protein Library Redesign And Optimization Procedure, Manish C. Saraf, Gregory L. Moore, Nina Goodey, Vania Y. Cao, Stephen J. Benkovic, Costas D. Maranas

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

A number of computational approaches have been developed to reengineer promising chimeric proteins one at a time through targeted point mutations. In this article, we introduce the computational procedure IPRO (iterative protein redesign and optimization procedure) for the redesign of an entire combinatorial protein library in one step using energy-based scoring functions. IPRO relies on identifying mutations in the parental sequences, which when propagated downstream in the combinatorial library, improve the average quality of the library (e.g., stability, binding affinity, specific activity, etc.). Residue and rotamer design choices are driven by a globally convergent mixed-integer linear programming formulation. Unlike many …

Development Of Dirhodium Sugar-Substituted Carboxylate And Acetamide Complexes And Evaluation Of Their Potential As Lectin Inhibitors, Bethany Masten

Undergraduate Review

No abstract provided.

Nmr Investigations Of Natural Organic Matter In Forest Ecosystems, Chris E. Johnson

Civil and Environmental Engineering - All Scholarship

No abstract provided.

1,1´-Diethyl-2,2´,3,3´,4,4´,5,5´-Octamethylferrocenium Tetracyanoethylenide, [Fe(C5etme4)2]+[Tcne]–, A Charge-Transfer Salt Magnetic Solid With A Novel Structural Motif, T. David Harris, Michael Castellani, Arnold L. Rheingold, William M. Reiff, Gordon T. Yee

Chemistry Faculty Research

1,1′-Diethyl-2,2′,3,3′,4,4′,5,5′-octamethylferrocene has been utilized as a one-electron donor in the synthesis of a tetracyanoethylene charge-transfer salt, [Fe(C₅EtMe₄)₂]⁺[TCNE]⁻. Structural characterization shows that it adopts an arrangement of anions and cations completely different from the usual π stacking seen in analogous decamethylferrocenium compounds. The TCNE radical sits along side of the ferrocene, nearly perpendicular to the planes of the C₅ rings. The nearly square geometry of the TCNE anion creates disorder over two orientations. [Fe(C₅EtMe₄)₂]⁺[TCNE]⁻ is a simple paramagnet exhibiting neither long-range …

Simplified Low Copy Number Dna Analysis By Post Pcr Purification, Pamela Smith

Electronic Theses and Dissertations

Frequently evidentiary items contain an insufficient quantity of DNA to obtain complete or even partial DNA profiles using standard forensic gentotyping techniques. Here, various methods of post PCR purification were evaluated for their effects on the sensitivity of fluophore-based allelic detection. A method of post PCR purification is described which increases the sensitivity of standard 28 cycle PCR such that low copy number DNA templates (<100 pg DNA) can be analyzed. Full profiles were consistently obtained with as little as 20 pg template DNA without increased cycle number. In mock case type samples with dermal ridge fingerprints, genetic profiles were obtained by amplification with 28 cycles followed by post-PCR purification whereas no profiles were obtained without purification of the PCR product. Allele drop-out, increased stutter, and contamination (allele drop-in) typical of LCN analysis were observed. A single incident of contamination was observed in a reagent blank (not duplicated upon re-amplification) however, no contamination was observed in negative amplification controls.

Discrimination Of Automobile Carpet Fibers Using Multiple Analytical Techniques And The Subsequent Creation Of A Searchable Data, Derek Dorrien

Electronic Theses and Dissertations

Forensic fiber examination is an important part of trace evidence analysis. Fibers may be recovered from a crime scene that could link a particular suspect to the scene. Clothing fibers are most frequently encountered but automobile carpeting fibers may also be recovered. An understanding of the frequency of occurrence and the discrimination power of different analytical techniques is needed in order to better establish the evidentiary value of automobile carpet fiber evidence. Seventy-five automobile carpet fiber samples were analyzed using a series of techniques ranging from nondestructive to destructive. These techniques included polarized light microscopy, fluorescence microscopy, microspectrophotometry, Fourier-transform infrared …

Isotope Sourcing Of Prehistoric Willow And Tule Textiles Recovered From Western Great Basin Rock Shelters And Caves: Proof Of Concept, Larry V. Benson, E. M. Hattori, H. E. Taylor, S. R. Poulson, E. A. Jolie

United States Geological Survey: Staff Publications

Isotope and trace-metal analyses were used to determine the origin of plants used to manufacture prehistoric textiles (basketry and matting) from archaeological sites in the western Great Basin. Research focused on strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (¹⁸O/¹⁶O) isotope ratios of willow (Salix sp.) and tule (Schoenoplectus sp.), the dominant raw materials in Great Basin textiles. The oxygen-isotope data indicated that the willow and tule used to produce the textiles were harvested from the banks of rivers or in marshes characterized by flowing water and not from lakes or sinks. The strontium-isotope …

Structural And Evolutionary Classification Of G/U Wobble Basepairs In The Ribosome, Neocles B. Leontis, Ali Mokdad, Maryna V. Krasovska, Jiří Sponer

Chemistry Faculty Publications

We present a comprehensive structural, evolutionary and molecular dynamics (MD) study of the G/U wobble basepairs in the ribosome based on high-resolution crystal structures, including the recent Escherichia coli structure. These basepairs are classified according to their tertiary interactions, and sequence conservation at their positions is determined. G/U basepairs participating in tertiary interactions are more conserved than those lacking any interactions. Specific interactions occurring in the G/U shallow groove pocket-like packing interactions (P-interactions) and some phosphate backbone interactions (phosphate-in-pocket interactions)-lead to higher G/U conservation than others. Two salient cases of unique phylogenetic compensation are discovered. First, a P-interaction is conserved …

Expression And Automated Purification Of Acetoacetyl Coa Thiolase From Sunflower Cotyledon, Jim Dyer, James Becker, Victor Geraldo, Mario Giron

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

In the sunflower (Helianthus annuus L.) cotyledons, two distinguishable thiolase activities have been identified: acetoacetyl CoA thiolase (AACT), specifically active during oxidation of short chain acetoacetyl CoA, and 3-oxoacyl CoA thiolase (OACT), active towards short, medium, and long-chain acyl CoAs. The purpose of this research was to optimize the purification of the AACT expressed in bacteria. Escherischia coli (E. coli) with the full-length sunflower AACT cDNA cloned into the expression vector pBAD-His B was induced for production of the AACT using 0.2% arabinose. Optimizing the conditions for protein purification is often an extremely empirical process requiring several iterations of a …

Mechanism Of Shifts Of Potentials Of Hemosorbents Based On Activated Carbons Caused By Adsorption Of Organic Toxicants, Mark Goldin, Yury Goldfarb, Mikhail M. Goldin

Faculty Publications and Presentations

No abstract provided.

Direct Detection Of Double-Stranded Dna: Molecular Methods And Applications For Dna Diagnostics, Indraneel Ghosh, Cliff I. Stains, Aik T. Ooi, David J. Segal

Cliff Stains Publications

Methodologies to detect DNA sequences with high sensitivity and specificity have tremendous potential as molecular diagnostic agents. Most current methods exploit the ability of single-stranded DNA (ssDNA) to base pair with high specificity to a complementary molecule. However, recent advances in robust techniques for recognition of DNA in the major and minor groove have made possible the direct detection of double-stranded DNA (dsDNA), without the need for denaturation, renaturation, or hybridization. This review will describe the progress in adapting polyamides, triplex DNA, and engineered zinc finger DNA-binding proteins as dsDNA diagnostic systems. In particular, the sequence-enabled reassembly (SEER) method, involving …

Sequence-Enabled Reassembly (Seer) Peptides For The Detection Of Dna Sequences, Aik T. Ooi, Cliff I. Stains, Jason R. Porter, Indraneel Ghosh, David J. Segal

Cliff Stains Publications

By combining custom zinc finger (ZF) DNA-binding technology [1,2] with protein fragment complementation [3], we have developed a technology, designated SEER (Sequence-Enabled Reassembly), that has the potential to “see” or detect genetic information within a living cell (Figure 1). These agents consist of two inactive parts of signal-generating peptides that have the ability to recognize specific DNA sequences. The two parts bind near each other in the presence of a user-defined DNA target site and generate a fluorescent signal. Two prototype SEER systems have been constructed, based on the reassembly of green fluorescent protein (SEERGFP) [4] and the enzyme β-lactamase …

Solvent Targeting, Avoidance And Recovery Trials (Start), Kealan Allen

Theses

Solvent is the largest-volume raw material used at Janssen Pharmaceutical (Ire) Ltd. Over 2.2 million m³ were used in 2004. The top 13 solvents make up 99% of this amount. There are two main uses for solvent on site, processing and cleaning. Processing uses 55% of the total solvent used on site, cleaning uses the remainder.

Waste solvent forms the majority of the hazardous waste produced at Janssen. Three treatment options exist at present for this waste: incineration, recovery for reuse and energy recovery. All of the hazardous waste produced on site must be exported for these treatment options, …

Analysis Of Nanoparticle Transmission Electron Microscopy Data Using A Public- Domain Image-Processing Program, Image, Gerd H. Woehrle, James E. Hutchison, Sai̇m Özkar, Richad G. Finke

Turkish Journal of Chemistry

The need to easily and quickly count larger numbers of nanoparticles, in order to obtain statistically useful size and size-distribution data, is addressed via the use of a readily available, free, public-domain program for particle counting, NIH-Image (and 2 others derived from it, Scion Image and Image J), collectively referred to herein as Image. The best protocols that we have found useful for the use of Image are reported; both appropriate as well as problematic applications of Image are then illustrated with a series of TEM images of Ir(0), Pd(0) and Au(0) nanoclusters. Methods to detect and image nanoclusters with …