Chemistry Commons^™

Estimation Of Bubble-Mediated Air–Sea Gas Exchange From Concurrent Dms And Co2 Transfer Velocities At Intermediate–High Wind Speeds, Thomas G. Bell, Sebastian Landwehr, Scott D. Miller, Warren J. De Bruyn, Adrian H. Callaghan, Brian Scanlon, Brian Ward, Mingxi Yang, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Simultaneous air–sea fluxes and concentration differences of dimethylsulfide (DMS) and carbon dioxide (CO2/ were measured during a summertime North Atlantic cruise in 2011. This data set reveals significant differences between the gas transfer velocities of these two gases (1kw/ over a range of wind speeds up to 21ms􀀀1. These differences occur at and above the approximate wind speed threshold when waves begin breaking. Whitecap fraction (a proxy for bubbles) was also measured and has a positive relationship with 1kw, consistent with enhanced bubble-mediated transfer of the less soluble CO2 relative to that of the more soluble DMS. However, the correlation …

Chemistry And Biochemistry News, Georgia Southern University

Biochemistry, Chemistry & Physics: News & Publications (2012-2023)

• Chemistry Honors Day

An Extended Jahn-Teller Hamiltonian For Large-Amplitude Motion: Application To Vibrational Conical Intersections In Ch3sh And Ch3oh, Mahesh B. Dawadi, Bishnu P. Thapaliya, David S. Perry

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

An extended Jahn-Teller Hamiltonian is presented for the case where the (slow) nuclear motion extends far from the symmetry point and may be described approximately as motion on a sphere. Rather than the traditional power series expansion in the displacement from the C3v symmetry point, an expansion in the spherical harmonics is employed. Application is made to the vibrational Jahn-Teller effect in CH3XH, with X = S, O, where the equilibrium CXH angles are 83° and 72°, respectively. In addition to the symmetry-required conical intersection (CI) at the C3v symmetry point, ab initio calculations reveal sets of six symmetry-allowed vibrational …

Development Of Entrapment Columns For The Study Of Affinity Based Analysis Of Drug–Protein Interactions, Shiden T. Azaria

Department of Chemistry: Dissertations, Theses, and Student Research

High-performance affinity chromatography (HPAC) is a type of liquid chromatography in which solutes are separated based on their binding to a stationary phase that is a biologically-related agent. Because of the strong and selective nature of many biological interactions, this method has already become a powerful technique for the purification and analysis of solutes that are complementary to the immobilized binding agent. Human serum albumin (HSA), the most abundant protein in the blood with concentrations of 35-50 mg/mL in serum, has interactions with many drugs, which can affect the absorption, distribution, metabolism and excretion of such agents.

The overall goal …

Real-Time Sensing Of Single-Ligand Delivery With Nanoaperture-Integrated Microfluidic Devices, W. Elliott Martin, Ning Ge, Bernadeta R. Srijanto, Emily Furnish, C. Patrick Collier, Christine A. Trinkle, Christopher I. Richards

Chemistry Faculty Publications

The measurement of biological events on the surface of live cells at the single-molecule level is complicated by several factors including high protein densities that are incompatible with single-molecule imaging, cellular autofluorescence, and protein mobility on the cell surface. Here, we fabricated a device composed of an array of nanoscale apertures coupled with a microfluidic delivery system to quantify single-ligand interactions with proteins on the cell surface. We cultured live cells directly on the device and isolated individual epidermal growth factor receptors (EGFRs) in the apertures while delivering fluorescently labeled epidermal growth factor. We observed single ligands binding to EGFRs, …

Determination Of Iron Content In Water, Sreenivasareddy Annem

All Capstone Projects

An easy, efficient and safe method was developed to determine iron in water samples. The method is an Iron Cell Test kit from Spectroquant in which firstly all iron ions are reduced to iron (II) ions by ascorbic acid. In a thioglycolate buffered medium, iron (II) reacts with a triazine derivative to form a purple complex that is determined photometrically. Calibration curve of iron standards was done with concentrations of 0.50, 1.0, 2.0, 3.0 and 4.0 ppm and it gave a R2 value of 0.9989 and straight line equation y=0.4749x-0.046. Iron analysis was done on two sets of water samples. …

Method Development For Analysis A Of Phthalates S By Hplc, Uma Ranganadham

All Capstone Projects

The purpose of this study is to develop an analytical method for determining the concentration of dialkyl phthalates as part of a larger study of phthalate degrading bacteria. Specifically, bacteria isolated from polyaromatic hydrocarbon contaminated riverine sediment are being determined for their proficiency in degrading dimethyl phthalate, diethyl phthalate, and dibutyl phthalate." HPLC instrument was used for analysis of these phthalate derivatives. A reversed phase isocratic and gradient elution and UV detection method was used for the individual and simultaneous determination of these phthalate derivatives. HPLC was carried out using a C18 column and spectrophotometric detection at 230nm. An isocratic …

Ismar / Rmcmr 2017 Abstract Book - Joint Conference Of The International Society Of Magnetic Resonance, The Rocky Mountain Conference On Epr, And The Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Abstracts from the 59th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, hosted jointly with the International Society of Magnetic Resonance and the Rocky Mountain Conference on EPR. Held in Quebec City, Canada, July 23-28, 2017.

Chelator-Free Radiolabeling Of Serrs Nanoparticles For Whole-Body Pet And Intraoperative Raman Imaging, Matthew A. Wall, Travis Shaffer, Stefan Harmsen, Darjus-Felix Tschaharganeh, Chun-Hao Huang, Scott W. Lowe, Charles Michael Drain, Moritz F. Kircher

Publications and Research

A single contrast agent that offers whole-body non-invasive imaging along with the superior sensitivity and spatial resolution of surface-enhanced resonance Raman scattering (SERRS) imaging would allow both pre-operative mapping and intraoperative imaging and thus be highly desirable. We hypothesized that labeling our recently reported ultrabright SERRS nanoparticles with a suitable radiotracer would enable pre-operative identification of regions of interest with whole body imaging that can be rapidly corroborated with a Raman imaging device or handheld Raman scanner in order to provide high precision guidance during surgical procedures. Here we present a straightforward new method that produces radiolabeled SERRS nanoparticles for …

Cadmium Chloride Dimensionality Changes From Ortho-Substituted Anilines, Stephanie Cernicek

Dissertations

Inorganic-organic hybrid metal halide materials have been of great interest recently due to the useful properties offered by such a combination. The inorganic portions usually consisting of MX₆^2- subunits, (M = Pb, Sn, Cd, Cu; X = Cl, Br, I) most often form 2-D perovskite layers where the metals are bridged by corner sharing halides. The organic portion, usually consisting of primary amines or anilines provides a template for the inorganic framework and in some cases, dictates the dimensionality (2-D, 1-D, 0-D) of the network. These materials have various applications in host-guest chemistry catalysis, and gas storage, or …

Review: New Frontiers In Metabolomics: From Measurement To Insight, Eli Riekeberg, Robert Powers

Robert Powers Publications

Metabolomics is the newest addition to the “omics” disciplines and has shown rapid growth in its application to human health research because of fundamental advancements in measurement and analysis techniques. Metabolomics has unique and proven advantages in systems biology and biomarker discovery. The next generation of analysis techniques promises even richer and more complete analysis capabilities that will enable earlier clinical diagnosis, drug refinement, and personalized medicine. A review of current advancements in methodologies and statistical analysis that are enhancing and improving the performance of metabolomics is presented along with highlights of some recent successful applications.

Level Lifetimes And The Structure Of 134Xe From Inelastic Neutron Scattering, Erin E. Peters, Anagha Chakraborty, Benjamin P. Crider, S. F. Ashley, E. Elhami, S. F. Hicks, A. Kumar, Marcus T. Mcellistrem, Sharmistha Mukhopadhyay, J. N. Orce, Francisco M. Prados-Estévez, Steven W. Yates

Chemistry Faculty Publications

The level structure of ¹³⁴Xe was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a 0⁺ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The 3⁻ octupole phonon has been confirmed, and the complete negative-parity multiplet …

Oligo(Ethylene Glycol)-Sidechain Microgels Prepared In Absence Of Cross-Linking Agent: Polymerization, Characterization And Variation Of Particle Deformability, Nicole Welsch, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We present a systematic study of self-cross-linked microgels formed by precipitation polymerization of oligo ethylene glycol methacrylates. The cross-linking density of these microgels and, thus, the network flexibility can be easily tuned through the modulation of the reaction temperature during polymerization. Microgels prepared in absence of any difunctional monomer, i.e. cross-linker, show enhanced deformability and particle spreading on solid surfaces as compared to microgels cross-linked with varying amounts of poly(ethylene glycol diacrylate) (PEG-DA) in addition to self-crosslinking. Particles prepared at low reaction temperatures exhibit the highest degree of spreading due to the lightly cross-linked and flexible polymer network. Moreover, AFM …

Cellular And Molecular Targets Of Menthol Actions, Murat Oz, Eslam El Nebrisi, Keun-Hang Susan Yang, Frank Christopher Howarth, Lina T. Al Kury

Mathematics, Physics, and Computer Science Faculty Articles and Research

Menthol belongs to monoterpene class of a structurally diverse group of phytochemicals found in plant-derived essential oils. Menthol is widely used in pharmaceuticals, confectionary, oral hygiene products, pesticides, cosmetics, and as a flavoring agent. In addition, menthol is known to have antioxidant, anti-inflammatory, and analgesic effects. Recently, there has been renewed awareness in comprehending the biological and pharmacological effects of menthol. TRP channels have been demonstrated to mediate the cooling actions ofmenthol. There has been new evidence demonstrating thatmenthol can significantly influence the functional characteristics of a number of different kinds of ligand and voltage-gated ion channels, indicating that at …

Distinct Properties Of The Triplet Pair State From Singlet Fission, M. Tuan Trinh, Andrew Pinkard, Andrew B. Pun, Samuel N. Sanders, Elango Kumarasamy, Matthew Y. Sfeir, Luis M. Campos, Xavier Roy, X.-Y. Zhu

Publications and Research

Singlet fission, the conversion of a singlet exciton (S₁) to two triplets (2 × T₁), may increase the solar energy conversion efficiency beyond the Shockley-Queisser limit. This process is believed to involve the correlated triplet pair state ¹(TT). Despite extensive research, the nature of the ¹(TT) state and its spectroscopic signature remain actively debated. We use an end-connected pentacene dimer (BP0) as a model system and show evidence for a tightly bound ¹(TT) state. It is characterized in the near-infrared (IR) region (~1.0 eV) by a distinct excited-state absorption (ESA) spectral feature, which …

The Entangled Triplet Pair State In Acene And Heteroacene Materials, Chaw Keong Yong, Andrew J. Musser, Sam L. Bayliss, Steven Lukman, Hiroyuki Tamura, Olga Bubnova, Rawad Hallani, Aurélie Meneau, Roland Resel, Munetaka Maruyama, Shu Hotta, Laura M. Herz, David Beljonne, John E. Anthony, Jenny Clark, Henning Sirringhaus

Chemistry Faculty Publications

Entanglement of states is one of the most surprising and counter-intuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which mediates the spin-conserving fission of one spin-0 singlet exciton into two spin-1 triplet excitons. Despite long theoretical and experimental exploration, the nature of the triplet-pair state and inter-triplet interactions have proved elusive. Here we use a range of organic semiconductors that undergo singlet exciton fission to reveal the photophysical properties of entangled triplet-pair states. We find that the triplet pair is bound with respect to …

Bimetallic Cooperativity In Proton Reduction With An Amido‐Bridged Cobalt Catalyst, Kenneth K. Kpogo, Shivnath Mazumder, Denan Wang, H. Bernhard Schlegel, Adam T. Fiedler, Cláudio N. Verani

Chemistry Faculty Research and Publications

The bimetallic catalyst [Co^II₂(L¹)(bpy)₂]ClO₄ (1), in which L¹ is an [NN′₂O₂] fused ligand, efficiently reduced H⁺ to H₂ in CH₃CN in the presence of 100 equiv of HOAc with a turnover number of 18 and a Faradaic efficiency of 94 % after 3 h of bulk electrolysis at −1.6 V (vs. Ag/AgCl). This observation allowed the proposal that this bimetallic cooperativity is associated with distance, angle, and orbital alignment of the two Co centers, as promoted by the unique Co−N_{amido …}

An Integrated Bioinformatic/Experimental Approach For Discovering Novel Type Ii Polyketides Encoded In Actinobacterial Genomes, Wubin Gao

Chemistry and Chemical Biology ETDs

Discovery of new natural products (NPs) is critical both for diseases treatment and crops protection. Numerous NP biosynthetic gene clusters (BGCs) in sequenced microbial genomes allow identification of new NPs through genome mining. Developing an integrated bioinformatic/experimental approach for discovering novel type II polyketides (PK-IIs) facilitates investigation of this family of NPs in an efficient, systematic way. Here, we developed an approach to analyze ketosynthase α/β (KSα/β) gene sequences to predict PK-II core structures, allowing us to target novel PK-II BGCs either from isolated genomic DNA or genomes from the NCBI databank, and to isolate novel PK-IIs produced by these …

31p Nmr Study Of Gtp-Cation Interactions, Zhiyan Song, Destiny L. Allen, Olarongbe Olubajo, Chellu S. Chetty

Georgia Journal of Science

Guanosine 5'-triphosphate (GTP) plays a pivotal role in many biologi­cal processes. The interactions of cations with GTP are essential to the stabilization of this nucleotide and the regulation of its functions. In this study, we present solution ³¹P NMR data on GTP samples in varied salt concentrations or pHs. From chemical shifts and T₁ , T₂ relaxations, it is concluded that the interaction strengths of cations with GTP are in the order of Ca²⁺ > Mg²⁺ > Li⁺ > Na⁺ for the cations, and in the order of beta > gamma > alpha for the phosphate groups. An …

Constructing Globular, Sheeted, And Helical Polyalanine Structures Using Nanotubes As Templates For Computational Studies, Caley Allen, Travis Bailey, Opie Bowen, Virginia Bryant, Nickolas Kitchens, Jason Lackey, Inez Mills, Om Patel, Nicholas Richardson, Shanda Sermons, Thomas Shaw, Calandra Stafford, Tiffany Stoney, Chad Ward, Samuel Zipperer, Thomas J. Manning

Georgia Journal of Science

In this experiment polyalanine was folded into globular, sheeted, and helical structures through the use of carbon nanotubes. The rigidity of the nanotubes allowed for molding the polyalanine into the various structures. Nanotubes of different diameters and volumes were used in this experiment. Once the three dimensional peptide structures were formed and detached from the carbon nanotubes, a number of thermodynamic calculations were performed. Computational meth­ods were used to calculate parameters such as Gibbs free energy, enthalpy, entropy, and molecular volume. By attaining the measure­ments of the phi and psi angles, Ramachandran plots were constructed using linear, globular, sheeted, and …

Intramolecular Nitrofuran Diels-Alder Reactions: Extremely Substituent-Tolerant Cycloadditions Via Asynchronous Transition States, Thomas Y. Cowie, Marcos Veguillas, Robert L. Rae, Mathilde Rougé, Justyna M. Zurek, Andrew W. Prentice, Martin J. Paterson, Magnus Bebbington

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Nitrofurans undergo intramolecular Diels-Alder reactions with tethered electron-poor dienophiles more rapidly and in higher yield than non-nitrated furans. Computational studies indicate that increased stabilization of a partial positive charge on the nitro-substituted carbon in both transition state and product is the driving force for these reactions. Frontier molecular orbital energy differences indicate a switch from normal to inverse electron demand upon nitration. There does not appear to be a contribution from any differences in aromatic stabilization energy between furans and nitrofurans. Calculations show that the nitrofuran reactions proceed via a highly asynchronous transition state allowing easier bond formation between two …

Chemical Tools For Delivery Of Carbon Monoxide, Lisa Berreau

Funded Research Records

No abstract provided.

New Strategies For Investigating Oxidative Aliphatic Carbon-Carbon Bond Cleavage Reactions, Lisa Berreau

Funded Research Records

No abstract provided.

Magnetic Nanostructure Application In Sers Detection Of Melatonin And Resonance Raman Characterization Of Binding Of Catechol Moieties With Antibiotic, Siqi Sun

USF Tampa Graduate Theses and Dissertations

Raman spectroscopy provides characteristic peaks of the target molecules that can be observed with appropriate laser, spectrometer and detector. These characteristic peaks can reveal ‘fingerprint’ information of a molecule even in a myriad of cases and combinations. It makes Raman spectroscopy a highly sensitive and selective analytical technique. Raman spectroscopy has a variety of chemical, environmental and biological applications. In this dissertation, modified Raman method are applied in life sciences and pharmaceutical studies.

The major challenge against development of Raman spectroscopy is how to improve the intensity of Raman signal. Surface Enhance Raman Scattering (SERS) and resonance Raman(RR) are utilized …

Systematic Elucidation Of Factors That Influence The Strength Of Tetrel Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations are used to examine the properties of heterodimers formed by a series of tetrel-containing molecules with NH₃ as universal Lewis base. TH₄ was taken as a starting point, with T= C, Si, Ge, and Sn. The H atoms were replaced by various numbers of F atoms: TH₃F, TF₃H, and TF₄ so as to monitor the effects of adding electron-withdrawing substituents. Unsubstituted TH₄ molecules form the weakest tetrel bonds, only up to about 2 kcal/mol. The bond is strengthened when the H opposite NH₃ is replaced by F, rising up …

Rational Drug Design Directed At Blocking The Initial Signaling Events In Lipopolysaccharide-Induced Sepsis., Christopher A. Tipton

Theses

Systemic Inflammatory Response Syndrome (SIRS) is classified as an immune system response to an infectious state. If left untreated, SIRS leads to sepsis, septic shock, end-organ dysfunction, and death. As a patient progresses through these stages, associations of acute respiratory distress, disseminated intravascular coagulation, and acute renal failure persist, resulting in millions of deaths annually. Lipopolysaccharide (LPS), a bacterial endotoxin, is released into the blood stream, triggering SIRS. LPS is found in the outer cell-wall of Gram-negative bacteria and is responsible for initiation of a devastating cytokine storm. One of the regions of LPS, lipid A, is a polyacylated glucosamine …

Chemical Investigations Of Fungal Natural Products For Drug Discovery, Danielle H. Demers

USF Tampa Graduate Theses and Dissertations

Natural products have, historically, played an important role in drug discovery. Nevertheless, drug resistance, pathogen evolution, and global climate change threaten human health and nearly all current anti-infective treatments on the market today. It is undeniable that new drug discovery efforts are needed with increasing urgency.

Bolstered by a rich history of discovering treatments in the world around us, natural products chemists continue to look to the environment with increasing understanding and emerging technologies that allow efficient, effective isolation of new chemical entities. This thesis will describe one such endeavor.

Focusing on fungal natural products, herein is described the isolation …

Self-Healing Polyphosphonium Ionic Networks, Elizabeth Gillies, Tyler J. Cuthbert, Joshua J. Jadischke, John R. De Bruyn, Paul J. Ragogna, Elizabeth R. Gillies

Chemistry Publications

Self healing, ionically crosslinked networks were prepared from poly(acrylic acid) (PAA) and poly(triethyl(4-vinylbenzyl)phosphonium chloride (P-Et-P) and their properties were studied. Three different ratios of PAA/P-Et-P were incorporated into the networks by varying the addition orders of the components. Swelling of the networks increased with increasing NaCl concentration when they were immersed in aqueous solution. All networks retained their structural integrity in 0.1 M NaCl. Studies of the rheological and tensile properties of the networks swelled in 0.1 M NaCl showed that PAA>P-Et-Pexhibited high elongation and viscoelastic properties suitable for self-healing with a relaxation time of ~30 …

Collaborative Research: Refining And Testing Methods For Identifying And Quantifying Gaseous Oxidized Mercury In Air, Seth Lyman

Funded Research Records

No abstract provided.

Mechanism-Informed Refinement Reveals Altered Substrate-Binding Mode For Catalytically Competent Nitroreductase, Warintra Pitsawong, Chad A. Haynes, Ronald L. Koder, David W. Rodgers, Anne-Frances Miller

Chemistry Faculty Publications

Nitroreductase from Enterobacter cloacae (NR) reduces diverse nitroaromatics including herbicides, explosives and prodrugs, and holds promise for bioremediation, prodrug activation and enzyme-assisted synthesis. We solved crystal structures of NR complexes with bound substrate or analog for each of its two half-reactions. We complemented these with kinetic isotope effect (KIE) measurements elucidating H-transfer steps essential to each half-reaction. KIEs indicate hydride transfer from NADH to the flavin consistent with our structure of NR with the NADH analog nicotinic acid adenine dinucleotide (NAAD). The KIE on reduction of p-nitrobenzoic acid (p-NBA) also indicates hydride transfer, and requires revision of …