Chemistry Commons^™

Characterization And Effect Of Metal Ions On The Formation Of The Thermus Thermophilus Sco Mixed Disulfide Intermediate, Liezelle C. Lopez, Nikita Mukhitov, Lindsey D. Handley, Cristina S. Hamme, Cristina R. Hofman, Lindsay Euers, Jennifer R. Mckinney, Amani D. Piers, Ellen Wadler, Laura M. Hunsicker-Wang

Chemistry Faculty Research

The Sco protein from Thermus thermophilus has previously been shown to perform a disulfide bond reduction in the Cu_A protein from T. thermophilus, which is a soluble protein engineered from subunit II of cytochrome ba ₃ oxidase that lacks the transmembrane helix. The native cysteines on TtSco and TtCu_A were mutated to serine residues to probe the reactivities of the individual cysteines. Conjugation of TNB to the remaining cysteine in TtCu_A and subsequent release upon incubation with the complementary TtSco protein demonstrated the formation of the mixed disulfide intermediate. The cysteine of …

Scaling Nonreactive Cross Flow Over A Heated Plate To Simulate Forest Fires, Nikolay Gustenyov, Nelson Akafuah, Ahmad Salaimeh, Mark A. Finney, Sara Mcallister, Kozo Saito

Institute of Research for Technology Development Faculty Publications

The paper reports visualization of the flow of smoke over a flat surface inside of a low-speed wind tunnel. A heating plate flush mounted on the wind tunnel floor simulated a spreading line fire that produces uniform heat flux under constant wind speed condition. A paper-thin cloth was soaked with commercially available Vaseline and placed on top of the heating plate; when it is heated, it produced thick white smoke, ideal for flow visualization. Two sides and top of the wind tunnel were made of a trans- parent acrylic sheet that enabled LED and laser sheet light illumination of the …

Interactions Between Spermine-Derivatized Tentacle Porphyrins And The Human Telomeric Dna G-Quadruplex, Navin C. Sabharwal , '14, Jessica Chen , '17, Joo Hyun Lee , '17, C. M. A. Gangemi, A. D'Urso, Liliya A. Yatsunyk

Chemistry & Biochemistry Faculty Works

G-rich DNA sequences have the potential to fold into non-canonical G-Quadruplex (GQ) structures implicated in aging and human diseases, notably cancers. Because stabilization of GQs at telomeres and oncogene promoters may prevent cancer, there is an interest in developing small molecules that selectively target GQs. Herein, we investigate the interactions of meso-tetrakis-(4-carboxysperminephenyl)porphyrin (TCPPSpm4) and its Zn(II) derivative (ZnTCPPSpm4) with human telomeric DNA (Tel22) via UV-Vis, circular dichroism (CD), and fluorescence spectroscopies, resonance light scattering (RLS), and fluorescence resonance energy transfer (FRET) assays. UV-Vis titrations reveal binding constants of 4.7 × 10⁶ and 1.4 × 10⁷ M⁻¹ and binding stoichiometry of …

Hot Spots And Hot Moments Of Soil Moisture Explain Fluctuations In Iron And Carbon Cycling In A Humid Tropical Forest Soil, Diego Barcellos, Christine S. O'Connell, Whendee L. Silver, Christof Meile, Aaron Thompson

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Soils from humid forests undergo spatial and temporal variations in moisture and oxygen (O₂) in response to rainfall, and induce changes in iron (Fe) and carbon (C) biogeochemistry. We hypothesized that high rainfall periods stimulate Fe and C cycling, with the greatest effects in areas of high soil moisture. To test this, we measured Fe and C cycling across three catenas at valley, slope, and ridge positions every two days for a two-month period in a rainforest in Puerto Rico. Over 12 days without rain, soil moisture, Fe^II, rapidly reducible Fe oxides (Fe^III_RR), …

Synthesis And Biological Evaluation Of Phaeosphaeride A Derivatives As Antitumor Agents, Victoria Abzianidze, Petr Beltyukov, Sofya Zakharenkova, Natalia Moiseeva, Jennifer Mejia, Alvin Holder, Yuri Trishin, Alexander Berestetskiy, Victor Kuznetsov

Chemistry & Biochemistry Faculty Publications

New derivatives of phaeosphaeride A (PPA) were synthesized and characterized. Anti-tumor activity studies were carried out on the HCT-116, PC3, MCF-7, A549, К562, NCI-Н929, Jurkat, THP-1, RPMI8228 tumor cell lines, and on the HEF cell line. All of the compounds synthesized were found to have better efficacy than PPA towards the tumor cell lines mentioned. Compound 6 was potent against six cancer cell lines, HCT-116, PC-3, K562, NCI-H929, Jurkat, and RPMI8226, showing a 47, 13.5, 16, 4, 1.5, and 7-fold increase in anticancer activity comparative to those of etoposide, respectively. Compound 1 possessed selectivity toward the NCI-H929 cell line (IC …

Mass Spectrometry And Nuclear Magnetic Resonance In The Chemometric Analysis Of Cellular Metabolism, Eli Riekeberg

Department of Chemistry: Dissertations, Theses, and Student Research

The development and awareness of Machine Learning and “big data” has led to a growing interest in applying these methods to bioanalytical research. Methods such as Mass Spectrometry (MS), and Nuclear Magnetic Resonance (NMR) can now obtain tens of thousands to millions of data points from a single sample, due to fundamental instrumental advances and ever-increasing resolution. Simple pairwise comparisons on datasets of this magnitude can obfuscate more complex underlying trends, and does a disservice to the richness of information contained within. This necessitates the need for multivariate approaches that can more fully take advantage of the complexity of these …

Pva/Chitosan/Silver Nanoparticles Electrospun Nanocomposites: Molecular Relaxations Investigated By Modern Broadband Dielectric Spectroscopy, Mohammad K. Hassan, Ahmed Abukmail, Alaa J. Hassiba, Kenneth A. Mauritz, Ahmed A. Elzatahry

Faculty Publications

In this study, we used broadband dielectric spectroscopy to analyze polymer nanofibers of poly(vinyl alcohol)/chitosan/silver nanoparticles. We also studied the effect of incorporating silver nanoparticles in the polymeric mat, on the chain motion dynamics and their interactions with chitosan nanofibers, and we calculated the activation energies of the sub-T_g relaxation processes. Results revealed the existence of two sub-T_g relaxations, the first gets activated at very low temperature (−90 °C) and accounts for motions of the side groups within the repeating unit such as –NH₂, –OH, and –CH₂OH in chitosan and poly(vinyl alcohol). The second …

Information-Driven Inverse Approach To Disordered Solids: Applications To Amorphous Silicon, Dil K. Limbu, Raymond Atta-Fynn, David A. Drabold, Stephen R. Elliott, Parthapratim Biswas

Faculty Publications

© Physical Review Materials

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Molecular Level Interactions And Transformations Of Natural Organic Matter Within The Environment, Benjamin J. Haywood

LSU Doctoral Dissertations

This work was done in order to deepen the understanding of interactions occurring during sorption of anthropogenic organic compounds and dissolved organic matter (DOM) onto soil. As well as the transformation DOM undergoes during the sorption process and the overall transformation OM undergoes in the environment. This was achieved through the use of a “bottom-up” synthetic investigation, “top-down” natural system study, and a combination of these approaches.

The “bottom-up” approach, discussed in Chapter 2, involved the synthesis of a modular multi-tiered engineered soil surrogate (ESS) designed to mimic OM and general trends identified in the literature that impacts sorption behavior. …

Bio-Inspired Polydopamine Surface Modification Of Nanodiamonds And Its Reduction Of Silver Nanoparticles, Yun Zeng, Wenyan Liu, Risheng Wang

Chemistry Faculty Research & Creative Works

Surface functionalization of nanodiamonds (NDs) is still challenging due to the diversity of functional groups on the ND surfaces. Here, we demonstrate a simple protocol for the multifunctional surface modification of NDs by using mussel-inspired polydopamine (PDA) coating. In addition, the functional layer of PDA on NDs could serve as a reducing agent to synthesize and stabilize metal nanoparticles. Dopamine (DA) can self-polymerize and spontaneously form PDA layers on ND surfaces if the NDs and dopamine are simply mixed together. The thickness of a PDA layer is controlled by varying the concentration of DA. A typical result shows that a …

Crystal Structure Of The 13-(E)-(2-Aminobenzylidene)-Parthenolide, Shobanbabu Bommagani, Narsihma R. Penthala, Sean Parkin, Peter A. Crooks

Chemistry Faculty Publications

The title compound, C₂₁H₂₅NO₃ [systematic name: (1aR,4E,7aS,8E,10aS,10bR)-8-(2-amino­benzyl­idene)-1a,5-dimethyl-2,3,6,7,7a,8,10a,10b-octa­hydro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-9(1aH)-one], was synthesized by the reaction of parthenolide [systematic name (1aR,7aS,10aS,10bS,E)-1a,5-dimethyl-8-methyl­ene-2,3,6,7,7a,8,10a,10b-octa­hydro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-9(1aH)-one] with 2-iodo­aniline via Heck reaction conditions. The mol­ecule is composed of fused ten-, five- (lactone), and three-membered (epoxide) rings. The lactone ring shows a flattened envelope-type conformation (r.m.s. deviation from planarity = 0.0477 Å), and bears a 2-amino­benzyl­idene substituent that is disordered over two conformations [occupancy …

Development Of Hydroxyapatite-Polymer Sorbents For The Removal Of Heavy Metal Ions From Waste Waters, Eleanora Charnetskaya

Chemistry Theses

Water pollution due to the presence of soluble metal ions is one of the greatest challenges to environmental scientists. Different methods have been explored to the removal of these soluble ions. Among these methods, elimination by sorption into/onto solid materials has been considered one of the successful approaches. Sorbent materials usually chemically interact with soluble ions and eliminate them by bond formation between the ions and the sorbent molecules. On the other hand, soluble ions can be also exchanged with inorganic sorbents in which other environmentally friendly ions can exchange with the soluble metal ions. In the current study, the …

Development, Characterization And Application Of Multi-Detector Flow Injection Systems Based On A Serial Flow Configuration For Simultaneous Multianalyte Determination, Aisha Rashed Al Hameidi Yammahi

Chemistry Theses

Oxidase enzymes have been used successfully in the analysis of several biochemical species such as glucose, lactate, pyruvate, creatine, creatinine, amino acids, cholesterol and sialic acid, by generating - in a single or consecutive reaction -hydrogen peroxide (H₂O₂) as a signal molecule which is commonly detected amperometrically. Some approaches have been also reported to use more than one enzyme in a given system to achieve multi-analyte determination. This study aims to evaluate a novel approach for n-analyte determination based on n-enzyme reactors (each is loaded with one or more oxidase enzyme) as well as n-1 catalase immobilized …

Sequestration Effect On The Open-Cyclic Switchable Property Of Warfarin Induce By Cyclodextrin: Time-Resolved Fluorescence Study, Naji Saleh Al-Dubaili

Chemistry Theses

In this work, the photophysical properties of the fluorescent anticoagulant drug warfarin (W) were examined in water and inside methyl-β-cyclodextrins (Me-β- CD) through absorption and time-resolved fluorescence measurements at pH 3 and 9 and upon the selective excitation of different isomers of warfarin at 280 and 320 nm. The values of binding constants (2.9 × 10³ M^–1 and 4.2 × 10² M^–1 for protonated and deprotonated forms, respectively) were extracted from the spectrophotometric data. Both absorption and time-resolved fluorescence results established that the interior of the macromolecular host binds preferentially the open protonated form, red shifts …

Development And Characterization Of A Portable Apparatus For Continuous Measurement Of Hydrogen Sulfide In Gas Streams, Bashar Yousef Abu Hattab

Chemistry Theses

A novel detection scheme for the hydrogen sulfide (H₂S) was described and patented recently by researchers at UAE University. This detection scheme and the described bench-scale analyzer offered the advantage of low-cost solution for real-time monitoring of percentile levels of H₂S with excellent signal stability. However, this previous work suffered from two major limitations, which are the relatively low sensitivity and slow response time, which mainly hindered its commercial utilization. Therefore, the aims of the present work were to enhance the detection sensitivity, decrease the response time, and develop a portable prototype of the H₂S analyzer based on the improved …

Lc-Ms/Ms Based Analysis Of Vitamins B3 And B6 In Healthy And Obese Emirati Population, Ghada Rashad Mohamed

Theses

Water-soluble vitamins like Vitamin B3, B6, and B9 are of utmost importance in human health and disease, as they are involved in numerous critical metabolic reactions. Not surprisingly, deficiencies of these vitamins have been linked to various disease states. For example, Vitamin B6 deficiency has been related to many diseases in humans especially in women with type 1 diabetes and in patients with systemic inflammation, liver disease, rheumatoid arthritis, and those infected with HIV. Similarly, derivatives of Vitamin B9 (such as folates), are needed to synthesize, repair, and methylate DNA as well as to act as a cofactor in certain …

Optimizing Peptide Fractionation To Maximize Content In Cancer Proteomics, Victoria Izumi

USF Tampa Graduate Theses and Dissertations

The purpose of the studies included in this thesis is to develop an effective an efficient method to study the proteome using separation and detection of peptides, when only a limited amount of sample, 10 micrograms of total protein or less, is available. The analysis will be applied to multiple myeloma cancer cells using ultra high-performance liquid chromatography-mass spectrometry for expression proteomics to illustrate utility. To detect low abundance peptides in a complex proteome, we use different strategies, including basic pH reversed-phase liquid chromatography (bRPLC), mass-to-charge fractionation in the mass spectrometer, and various liquid chromatography gradients to increase peptide separation …

‘Cassette’-Ises (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds For Hydrolytic Kinetic Resolution Across A Range Of Epoxides, Sangeeta Dey, Douglas R. Powell, Chunhua Hu, David B. Berkowitz

Department of Chemistry: Faculty Publications

‘Cassette’-ISES (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides

A new ‘Cassette’-In Situ Enzymatic Screen (ISES) for combinatorial catalysis is introduced. This allows the experimentalist to obtain an information-rich readout, in real time, providing an estimate of the sense and magnitude of enantioselectivity across more than one substrate. In its first iteration, the screen identified Co^III-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities.

Interfacing Nickel Nitride And Nickel Boosts Both Electrocatalytic Hydrogen Evolution And Oxidation Reactions, Fuzhan Song, Wei Li, Jiaqi Yang, Guanqun Han, Peilin Liao, Yujie Sun

Chemistry and Biochemistry Faculty Publications

Electrocatalysts of the hydrogen evolution and oxidation reactions (HER and HOR) are of critical importance for the realization of future hydrogen economy. In order to make electrocatalysts economically competitive for large-scale applications, increasing attention has been devoted to developing noble metal-free HER and HOR electrocatalysts especially for alkaline electrolytes due to the promise of emerging hydroxide exchange membrane fuel cells. Herein, we report that interface engineering of Ni₃N and Ni results in a unique Ni₃N/Ni electrocatalyst which exhibits exceptional HER/HOR activities in aqueous electrolytes. A systematic electrochemical study was carried out to investigate the superior hydrogen …

Several Levels Of Theory For Description Of Isotope Effects In Ozone: Effect Of Resonance Lifetimes And Channel Couplings, Alexander Teplukhin, Dmitri Babikov, Igor Gayday

Chemistry Faculty Research and Publications

In this paper, two levels of theory are developed to determine the role of scattering resonances in the process of ozone formation. At the lower theory level, we compute resonance lifetimes in the simplest possible way, by neglecting all couplings between the diabatic vibrational channels in the problem. This permits to determine the effect of “shape” resonances, trapped behind the centrifugal barrier and populated by quantum tunneling. At the next level of theory, we include couplings between the vibrational channels, which permits to determine the role of Feshbach resonances and interaction of different reaction pathways on the global PES of …

Development Of Betulinic Acid Triazole Conjugates As Potential Anti-Cancer Agents, Gayathri Jampana

Theses and Dissertations

Betulin and betulinic acid are pentacyclic triterpenoid natural product isolated from the bark of birch trees. While betulin is abundantly available in the bark, betulinic acid is present in scarce quantities in nature. However, betulinic acid can be conveniently synthesized from betulin via simple redox manipulations. Betulinic acid shows selective cytotoxicity profile against cancer cells in vitro while being relatively safe for normal cells. One of the challenges for the clinical development of betulinic acid is its lack of aqueous solubility. The three key structural features of betulin/betulinic acid that have been routinely exploited for structural modifications to enhance their …

Synthesis, Characterization And Application Of Structurally Diverse Poly(Chalcogenylene Vinylene)S, Zhen Zhang

Chemistry and Chemical Biology ETDs

Conjugated polymers have found widespread applications in flexible and printable electronic devices, among which poly(thienylene vinylene) (PTV) displays outstanding optoelectronic properties and promising applications. However, further studies of its structure-property-function relationship have been greatly impeded mainly due to the synthetic difficulty of generating new structures beyond its rudimentary form.

To further investigate this class of material, I have developed a facile methodology for the preparation of structurally diverse poly(chalcogenylene vinylene)s (PCVs) through a combination of acyclic diene metathesis (ADMET) polymerization and post-polymerization modification techniques. Specifically, a series of halogenated and cross-conjugated PCVs have been designed and synthesized, followed by complete …

Synthesis Of Some Fossils Of Ferrocene Carboxylic Acid And Their Classification Based On Tif Tn, Н Tulakov,, I. Askarov,, Yu. Isaeva,, K. Otaxonov

Scientific journal of the Fergana State University

The synthesis of some ferrocenecarboxylic acid derivatives and assignment of code numbers for them according to the commodity nomenclature of foreign economic activity (CN FEA) is described in the article.

Comparison Of Theoretical And Experimental Geometric Characteristics Of Betulin, A. Eshimbetov,, Sh Kurbanbaeva,, Sh. Turgunbaev,, A. Xaitbaev

Scientific journal of the Fergana State University

The study of betulin and its derivatives is of great importance, since the programs of mathematical modeling enable a qualitative study of the relationship between structure-spectrum-properties. As a result of the theoretical search, it is possible to determine still non-synthesized highly-biologically active derivatives of betulin

Dependence Of Nmr Chemical Shifts Upon Ch Bond Lengths Of A Methyl Group Involved In A Tetrel Bond, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Four different Lewis acids that might participate in a tetrel bond with a nucleophile (SEt₂Me⁺, NMe₄⁺, SMe₂, NMe₃) are examined. The NMR chemical shifts of the methyl C and H atoms are calculated as the CH bond lengths are systematically stretched and contracted, in the absence of a base. The C shielding diminishes by roughly 2 ppm for a stretch of 0.01 Å, while that of H drops by only 0.3 ppm. The deshieldings caused purely by the bond length changes are far too small to account for the …

Acidity And Antioxidant Activity Of Cold Brew Coffee., Niny Z. Rao, Megan Fuller

College of Life Sciences Faculty Papers

The acidity and antioxidant activity of cold brew coffee were investigated using light roast coffees from Brazil, two regions of Ethiopia, Columbia, Myanmar, and Mexico. The concentrations of three caffeoylquinic acid (CQA) isomers were also determined. Cold brew coffee chemistry was compared to that of hot brew coffee prepared with the same grind-to-coffee ratio. The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13. The hot brew coffees were found to have higher concentrations of total titratable acids, as well as higher antioxidant activity, than that of their cold brew …

Guanidinium Compounds, Stephen Dimagno, Bao Hu

Department of Chemistry: Faculty Publications

The present application provides , inter alia , chemical com pounds useful as synthesis intermediates , said compounds comprising one or more guanidinium moieties and a hyper valent iodine atom . Methods for making these compounds are also provided.

Resurrecting The Regulatory Properties Of The Ostreococcus Tauri Adp-Glucose Pyrophosphorylase Large Subunit, Carlos M. Figueroa, Misty L. Kuhn, Benjamin L. Hill, Alberto A. Iglesias, Miguel A. Ballicora

Chemistry: Faculty Publications and Other Works

ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step for the synthesis of glycogen in cyanobacteria and starch in green algae and plants. The enzyme from cyanobacteria is homotetrameric (α4), while that from green algae and plants is heterotetrameric (α2β2). These ADP-Glc PPases are allosterically regulated by 3-phosphoglycerate (3PGA, activator) and inorganic orthophosphate (Pi, inhibitor). Previous studies on the cyanobacterial and plant enzymes showed that 3PGA binds to two highly conserved Lys residues located in the C-terminal domain. We observed that both Lys residues are present in the small (α) subunit of the Ostreococcus tauri enzyme; however, one of these …

Heme Dissociation From Myoglobin In The Presence Of The Zwitterionic Detergent N,N-Dimethyl-N-Dodecylglycine Betaine: Effects Of Ionic Liquids, Eric M. Kohn, Joshua Y. Lee, Anthony Calabro, Timothy Vaden, Gregory A. Caputo

College of Science & Mathematics Departmental Research

We have investigated myoglobin protein denaturation using the zwitterionic detergent Empigen BB (EBB, N,N-Dimethyl-N-dodecylglycine betaine). A combination of absorbance, fluorescence, and circular dichroism spectroscopic measurements elucidated the protein denaturation and heme dissociation from myoglobin. The results indicated that Empigen BB was not able to fully denature the myoglobin structure, but apparently can induce the dissociation of the heme group from the protein. This provides a way to estimate the heme binding free energy, ΔGdissociation. As ionic liquids (ILs) have been shown to perturb the myoglobin protein, we have investigated the effects of the ILs 1-butyl-3-methylimidazolium chloride (BMICl), 1-ethyl-3-methylimidazolium acetate (EMIAc), …

Synthesis And Characterization Of A Series Of Vanadium ( Iv ) Complexes With The Kläui Ligand, Xiao Wu

Theses and Dissertations

Cyclopentadienyltris (dibutyl phosphito-P) cobaltate, {(C5H5)Co[(OR)2PO]3}– (R=Bu), is a tripodal ligand and also called Kläui ligand (R=Bu). The synthesis and characterization of several vanadium(III) and vanadium(IV) complexes containing Kläui ligand (R=Bu) as the catalytic models to catalyst the oxidation reaction of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butyl-o-benzoquinone (3,5-DTBQ) are detailed here. Chapter II details the synthesis of the supersandwiches and Kläui ligand (R=Bu). Chapter III details the synthesis of vanadium monomeric complexes containing Kläui ligand (R=Bu). Chapter IV details the vanadium dimeric bridging complexes synthesized by different vanadium monomers from Chapter III. Chapter V details the catalytic activities of these vanadium complexes.