Chemistry Commons^™

Insights Into The Effect Of Metal Ions And Conformational Change On Binding Between Protective Antigen And Tumor Endothelial Marker 8, Zhe Jia, Christine Ackroyd, Kenneth Christensen, Brian Dominy

Chemistry Annual Research Symposium

No abstract provided.

Development Of A Direct Activity Probe For Rho-Associated Protein Kinase, Maia Kelly

Department of Chemistry: Dissertations, Theses, and Student Research

Hepatocellular carcinoma (HCC) is an extremely aggressive form of liver cancer with a low survival rate due to high recurrence. Increases in Rho-associated Protein Kinase (ROCK) activity are correlated with a more aggressive, metastatic phenotype associated with advanced HCC. Inhibitors for ROCK have shown potential for the reduction of this metastatic phenotype of HCC. We outline the design and optimization of a direct activity sensor for ROCK that utilizes a phosphorylation-sensitive sulfonamido-oxine fluorophore, termed Sox, and is capable of reporting on the inhibition of ROCK. This CSox-based activity probe utilizes chelation-enhanced fluorescence (ex. = 360 nm and em. = 485 …

Discovery Of Low-Molecular Weight Novel Serum Biomarkers For Diagnosing Preeclampsia And Alzheimer's Disease, Swati Anand

Theses and Dissertations

Preeclampsia (PE), a life threatening pregnancy-related disorder, is characterized mainly by new onset of hypertension and proteinuria after 20 weeks of gestation. Currently, PE cannot be predicted prior to onset of symptoms and there is no cure for the disease. There is a clear value in having biomarkers able, early in a pregnancy, to identify women at risk for PE so that proper treatment therapies could be developed. Although a number of serum candidate markers have been proposed to be altered in PE patients, their use is limited due to poor sensitivity and specificity. Therefore, there is ongoing need for …

Nitrous Oxide In The Atmosphere: First Measurements Of A Lower Thermospheric Source, Patrick E. Sheese, Kaley A. Walker, Chris D. Boone, Peter F. Bernath, Bernd Funke

Chemistry & Biochemistry Faculty Publications

Nitrous oxide (N₂O) is an important anthropogenic greenhouse gas, as well as one of the most significant anthropogenic ozone-depleting substances in the stratosphere. The satellite-based instrument Atmospheric Chemistry Experiment-Fourier Transform Spectrometer has been observing the Earth's limb since 2004 and derives profiles of N₂O volume mixing ratios in the upper troposphere to the lower thermosphere. The resulting climatology shows that N₂O is continuously produced in the lower thermosphere via energetic particle precipitation and enhanced N₂O is present at all latitudes, during all seasons. The results are consistent with an N₂O …

14-3-3Ζ Regulation Of Metastasis Through Mediation Of Liprin-Α And Liprin-Β, Rachel Hynes

Theses and Dissertations

Cancer is a set of varied and diverse diseases that share common characteristics, such as active proliferation, increased replicative potential, and tissue invasion or metastasis. One protein, 14-3-3ζ, is shown to be upregulated in a number of different cancers and also correlates with poor patient prognosis, recurrence, and mortality. This protein comes from a family of adapter proteins known for their scaffolding ability, pro- and anti-oncogenic capabilities, and affinity for phosphorylated substrates. It has been shown previously to participate in cancer progression, subversion of apoptosis, and to increase chemoresistance. Herein we will discuss the ability of 14-3-3ζ to promote distant-site …

1h, 13c And 15n Resonance Assignments And Secondary Structure Analysis Of Translation Initiation Factor 1 From Pseudomonas Aeruginosa, Alejandra Bernal, Yanmei Hu, Stephanie O. Palmer, Aaron Silva, James M. Bullard, Yonghong Zhang

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

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen and a primary cause of infection in humans. P. aeruginosa can acquire resistance against multiple groups of antimicrobial agents, including β-lactams, aminoglycosides and fluoroquinolones, and multidrug resistance is increasing in this organism which makes treatment of the infections difficult and expensive. This has led to the unmet need for discovery of new compounds distinctly different from present antimicrobials. Protein synthesis is an essential metabolic process and a validated target for the development of new antibiotics. Translation initiation factor 1 from P. aeruginosa (Pa-IF1) is the smallest of the three initiation factors that acts …

Removal Of Cu (Ii) And Pb (Ii) From Aqueous Solution Using Engineered Iron Oxide Nanoparticles, Carlos Tamez, Rebecca Hernandez, Jason Parsons

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

Nano-sized Fe3O4 and Fe2O3 were synthesized using a precipitation method. The nanomaterials were tested as adsorbents for the removal of both Cu2+ and Pb2+ ions. The nanomaterials were characterized using X-ray powder diffraction to determine both the phase and the average grain size of the synthesized nanomaterials. Batch pH studies were performed to determine the optimum binding pH for both the Cu2+ and Pb2+ to the synthesized nanomaterials. The optimum binding was observed to occur at pH 4 and above. Time dependency studies for Cu2+ and Pb2+ showed the binding occurred within the first five minutes of contact and remained …

Forcespinning: A New Method For The Mass Production Of Sn/C Composite Nanofiber Anodes For Lithium Ion Batteries, Victor Agubra, Luis Zuniga, David De La Garza, Luis Gallegos, Madhab Pokhrel, Mataz Alcoutlabi

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

The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280 °C followed by carbonization at 800 °C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724 mA …

Fluorescence Of Supported Phospholipid Bilayers Recorded In A Conventional Horizontal-Beam Spectrofluorometer, Elizaveta A. Kovrigina, Evgeni L. Kovrigin

Chemistry Faculty Research and Publications

Supported phospholipid bilayers are a convenient model of cellular membranes in studies of membrane biophysics and protein-lipid interactions. Traditionally, supported lipid bilayers are formed on a flat surface of a glass slide to be observed through fluorescence microscopes. This paper describes a method to enable fluorescence detection from the supported lipid bilayers using standard horizontal-beam spectrofluorometers instead of the microscopes. In the proposed approach, the supported lipid bilayers are formed on the inner optical surfaces of the standard fluorescence microcell. To enable observation of the bilayer absorbed on the cell wall, the microcell is placed in a standard fluorometer cell …

Novel Sputtered Stationary Phases For Solid Phase Microextraction, And Other Coatings And Materials For Surface Applications, Anubhav Diwan

Theses and Dissertations

The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for different times to yield fibers with different thicknesses. Piranha treatment of the surface increased the concentration of silanol groups, which underwent condensation with vapor deposited octadecyldimethylmonomethoxy silane to incorporate octadecyl chains onto the fiber surfaces. Silanized, sputtered fibers were preconditioned for 3 h at 320 °C to remove the unreacted chains. Comparison of the extraction efficiencies …

Toward High Performance Nanocarbon Fibers, Michaela R. Pfau

Master's Theses

High performance carbon fibers (CFs) have been a commercially available since their commercial boom in the 1970s, and are generally produced via carbonization of poly (acrylonitrile) (PAN). More recently, carbon nanomaterials like graphene and carbon nanotubes (CNTs) have been discovered and have shown excellent mechanical, thermal, and electrical properties due to their sp² carbon repeating structure. Graphene and CNTs can both be organized into macroscopic fibers using a number of different techniques, resulting in fibers with promising mechanical performance that can be readily multifunctionalized. In some cases, the two materials have been combined, and the resulting hybrid fibers have …

Electrochemical Syntheses Of Graphene And Its Composites, Bo Zhao, Li Jiang, Ming-Hui Yuen, Xian-Zhu Fu, Rong Sun, Ching-Ping Wong

Journal of Electrochemistry

Graphene is a kind of ideal two-dimensional flat carbon nanomaterials which have unique chemical and physical properties. The attractive potential applications must be based on the high quality mass production of graphene. However, it remains a huge challenge. An electrochemical approach is a fast, environmental friendly and easy-operating method. single- or multi-layered graphene flakes can easily be produced in short periods of time. In this review, the structure, properties and preparation methods of graphene are first introduced. Accordingly, the electrochemical approaches used for the productions of graphene flakes, graphene/inorganic nanocomposites, graphene/polymer composites and graphene analogues are highlighted. Finally, challenges and …

Synthesis Of Fe, N-Doped Graphene/Carbon Black Composite With High Catalytic Activity For Oxygen Reduction Reaction, Chi Chen, Zhi-You Zhou, Xin-Sheng Zhang, Shi-Gang Sun

Journal of Electrochemistry

Oxygen reduction reaction (ORR) is a bottleneck for improving the efficiency of proton-exchange membrane fuel cells as a cathode reaction due to its sluggish kinetics. The exploitation of low cost and high performance non-precious metal catalysts such as Fe/N/C based materials toward ORR has attracted extensive attentions. In this work, the Fe, N-doped graphene nanosheets/carbon black composite was prepared by hydrothermal polymerization and followed by a twice-heat-treatment procedure using 2-aminoimidazole as an N precursor, FeCl₃ as an Fe precursor and KJ600 carbon black as a support. The TEM images revealed that the graphene nanosheets were separated by carbon black …

Temperature Effects On Properties Of Aerospace Nickel Hydrogen Cells, Hai-Chang Zhang, Yu-Qi Diao, Wen-Cheng Ming, Xue-Ying Ren, Fei Ding

Journal of Electrochemistry

This has been done using the 60 Ah nickel-hydrogen cell to investigate the temperature effects on properties of aerospace nickel hydrogen cells. The charge-discharge, trickle charge, overcharge, self-discharge and cycle life tests were carried out at different temperatures. The results show that the discharge capacity and overcharge rate were increased first, and then decreased with the raising temperature. On the other hand, the trickle charge value and the 3 days self-discharge rate were raised with increasing temperature. When the temperature was -5 ^oC, the discharge capacity of cell reached the maximum discharge capacity of 63.68 Ah. Based on the …

Electrochemical H2O2 Sensor Based On The Co-Immobilization Of Phosphmolybdic Acid And Graphene On Pedot Film Electrode With Nafion, Hao-Xian Zhou, Jun-Ming Zhang, Zhi-Yu Qu, Pan-Yu Zhang, You-Jun Fan

Journal of Electrochemistry

With a glassy carbon electrode (GCE) as the substrate, the poly(3,4-ethylenedioxythiophene) (PEDOT) film electrode was prepared through the electrochemical polymerization method, then a novel non-enzymatic electrochemical H₂O₂ sensor was fabricated by co-immobilizing phosphomolybdic acid and graphene with Nafion on the PEDOT/GCE electrode. The modified electrodes were characterized by scanning electron microscopy (SEM), while the responsive properties of the sensor to H₂O₂ were investigated by cyclic voltammetry and chronoamperometry. The results demonstrated that, under the optimized conditions, the sensor exhibited good electrocatalytic performance for H₂O₂ reduction. The current response of the sensor …

Improving The Electrochemical Properties Of Polyaniline By Doping With Silver Ions, Hui Xu, Jin-Juan Pu, Yong Chen, Jian Liu

Journal of Electrochemistry

Polyaniline (PANI) is an attractive candidate among the various conductive polymers based on its unique doping/de-doping behavior, intrinsic electrical conductivity, facile synthesis, and environmental stability. However, the poor conductivity and cycle stability in an acid medium have restricted its applications. Our work aims at solving the above problems effectively by doping silver ions into PANI. The PANI and PANI doped with silver ions (PANI/Ag⁺) were synthesized by a facile interfacial polymerization process, which used aniline as a starting material in toluene in contact with an aqueous solution of silver nitrate varied from 0.04 mol•L^-1 to 0.20 mol⋅L …

Effect Of Flame Retardant On Electrochemical Performances Of Lithium Ion Battery With Lini0.4Co0.2Mn0.4O2 As A Positive Electrode Material, Yan-Zhuo Lv, Yong-Xian Ge, Zhen-Bo Wang, Ke Ke

Journal of Electrochemistry

The effect of flame retardant on the electrochemical performances of lithium ion battery by using LiNi_0.4Co_0.2Mn_0.4O₂ as a positive material was studied by measuring the first charge-discharge, cycling, circulation, and AC impedance curves. The experimental data indicated that the discharge capacity of the battery decreased, while the charge transfer resistance and the lithium ion diffusion resistance increased with the increases in the concentrations of the flame retardant in the electrolyte solutions. Furthermore, the stability of the battery at small discharge ratios and the cyclic performance were also improved by the addition of flame …

Electricity Generation Of Microbial Fuel Cell Using Stainless Steel Mesh As Cathode, Hong-Yan Dai, Hui-Min Yang, Xian Liu, Xuan Jian, Xiu-Li Song, Zhen-Hai Liang

Journal of Electrochemistry

In the present work, a dual-chamber microbial fuel cell (MFC) was constructed with aeration tank sludge as an inoculum, carbon felt as an anode and stainless steel mesh without any modification as a cathode. The influence of the cathode size was investigated in terms of voltage output, power generation and electrochemical impedance. The long-term durability of the stainless steel mesh cathode was also evaluated. Results showed that the stainless steel mesh exhibited satisfactory long-term durability as MFC cathode. When the stainless steel mesh size was 2 × 2 cm², the maximum output voltage, power density, the internal resistance …

Electrochemical Detection Of Hydrogen Peroxide At Aunps Modified Electrode Using P-Hydroxyphenylboronic Acid As A Precursor, Chun-Yan Wang, Xiao-Qiu Liu, Ying-Xin Qi

Journal of Electrochemistry

We developed a new method for electrochemical detection of hydrogen peroxide (H₂O₂) based on boronate oxidation of p-hydroxyphenylboronic acid. This method using p-aminophenol which is produced from the reaction of H₂O₂ and p-aminophenylboronic acid as a well electrochemical probe, combined with a gold nanoparticles (AuNPs) modified electrode for an indirect detection of H₂O₂. Because of the large surface area and enhanced electrocatalytic behavior by the AuNPs modified electrode, the detection sensitivity was improved. The method could detect H₂O₂ in the concentration range of 1 ~ 100 …

Electrochemical Determination Of Hg(Ii) At Gold Nanoparticles@Carbonaceous Microspheres Modified Electrode, Tian-Yu Qiu, Ming-Chun Wang, Xian-Feng Du, Tian-Jia Jiang, Xing-Jiu Huang

Journal of Electrochemistry

The gold nanoparticles@carbonaceous microspheres (Au@CMSs) and  Au@CMSs modified glassy carbon electrode (GCE) were prepared. The Au@CMSs modified  GCE was further examined for possible sensitive detection of mercury ions (Hg(II)) in an aqueous solution by square wave anodic stripping voltammetry (SWASV). The excellent performance was found in the stripping analysis of Hg(II) in 0.1 mol•L^-1 NaAc-HAc(pH=5.0) with a sensitivity of 25.863 A•(mol•L^-1)^-1 and a detection limit of 3.69×10^-8 mol•L^-1 based on the 3σ method.

Fabrication Of Riboflavin Electrochemical Sensor Based On Au Nanoparticles/Polydopamine/Carbon Nanotubes Modified Glassy Carbon Electrode, Hua-Ping Peng, Mei-Ling Yu, Xin Liu, Pan Liu, Wei Chen, Ai-Lin Liu, Xin-Hua Lin

Journal of Electrochemistry

A novel electrochemical platform for the high sensitivity detection of riboflavin was constructed by Au nanoparticles/polydopamine/carbon nanotubes (Au-PDA-MWCNTs) nanocomposite modified glassy carbon electrode. The Au-PDA-MWCNTs nanocomposite was synthesized by in situ reduction method. The characteristics of the as-prepared Au-PDA-MWCNTs nanocomposite modified electrodes were investigated by using UV-Vis spectroscopy, scanning electron microscopy (SEM) and electrochemical methods. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrochemical behavior of riboflavin (RF) at Au-PDA-MWCNTs nanocomposite modified electrodes. The results demonstrated that the present electrochemical sensor exhibited a wide linear range from 5×10^-9 mol•L^-1to 1×10^-5 mol•L …

The Study On Comparison Of Electrochemical Performance In Microbial Fuel Cell With Glucose And Sodium Acetate Acting As Substrates, Lei Fan, Yu Zhao, Ting Li, Qin-Bo Yuan, En-Zhi Wang, Xiao-Bin Wang, Jun-Wen Wang

Journal of Electrochemistry

By inoculating aerobic sludge and anaerobic sludge from the sewage treatment plant, two sets of dual-chamber microbial fuel cells (MFCs) were built with either glucose or sodium acetate acting as a substrate. Accordingly, the electrochemical performances of MFCs were explored with the concentration of the substrates being 0.0335 mol⋅L^-1. The results of the comparative study in glucose system and sodium acetate system showed that the impedance values of anodic half cell were 222 Ω for glucose and 213.67 Ω for sodium acetate, implying no significant effect on the internal resistance in battery with the different substrates. The exchange …

Adsorption Behavior Of Rhodamine 6g On Silver Surfaces Studied By Electrochemical Surface-Enhanced Raman Spectroscopy, Chan-Juan Chen, Cheng Zong, Guo-Kun Liu, Bin Ren

Journal of Electrochemistry

Rhodamine 6G (R6G) is one of the most common probe molecules employed in single molecule surface-enhanced Raman spectroscopy (SM-SERS). The study in adsorption behavior of R6G will help understand the interactions between R6G and surface. In this paper, we used electrochemical surface-enhanced Raman spectroscopy (SERS) to study the potential-dependent adsorption behavior of R6G on silver electrodes. Our results show that when the potential moved negatively, the orientation of R6G on silver surface changed from vertical to inclined adsorption. This result indicates that the abnormal SM-SERS spectra of R6G observed in the former SM-SERS studies from other research groups are due …

An Electrochemical Investigation Of P-Sulfophenylazo Calix[4]Arene In A Buffer Solution, Xing Yang, Ping Chen

Journal of Electrochemistry

The p-sulfophenylazo calix[4]arene was synthesized through the diazotization-coupling reaction between calix[4]arene and p-aminobenzene sulfonic acid. The UV-Vis spectroscopy, Infrared spectroscopy, and nuclear magnetic resonance (NMR) were used to characterize the as-prepared p-sulfophenylazo calix[4]arene. The electrochemical behaviors of p-sulfophenylazo calix[4]arene were investigated by cyclic voltammetry and chronoamperometry using CH₃COOH-CH₃COONa as a buffer solution. The result shows that the p-sulfophenylazo calix[4]arene exhibited a pair of redox peaks in a scan potential region of -0.5 ~ 1 V. The oxidation and reduction peak potentials were 0.302 V and -0.003 V, respectively, and changed with the scanning rates. In addition, …

Chemistry And Biochemistry News, Georgia Southern University

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

• Brawns of Brainy Polymers
• You Can't Always Eat What You Want
• Biomaterials Serves as Inspiration for the Youth
• BSL-2 Lab Unique to GSU Is Up and Running
• Polymer Coatings Program at GSU Is Opening Doors
• Professor Wins Prestigious Rising Star Award

Catalysis Of The Aza-Diels-Alder Reaction By Hydrogen And Halogen Bonds, Vincent De Paul Nzuwah-Nziko, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The combination of H2C=NH and cis-1,3-butadiene to form a six-membered ring was examined by quantum calculations. The energy barrier for this reaction is substantially lowered by the introduction of an imidazolium catalyst with either a H or halogen (X) atom in the 2-position, which acts via a H or halogen bond to the N atom of the imine, respectively. X=I has the largest effect, and Cl the smallest; Br and H are roughly equivalent. The catalyst retards the formation of the incipient N-C bond from imine to diene while simultaneously accelerating the C-C bond formation. The energy of the π* …

Chemical Investigation Of Antarctic Marine Organisms & Their Role In Modern Drug Discovery, Jacqueline Lee Fries

USF Tampa Graduate Theses and Dissertations

The chemicals produced by biological systems, whether proteins, peptides, or terpenes, will always provide an intriguing topic for researchers. Invisibly controlling every aspect of nature, these molecules are responsible for life, evolution, and death. Specifically, here is described the secondary metabolites produced by Antarctic marine organisms as well as others, and how they are used to defend or attract other animals while potentially providing health benefits to mankind. This is done through collection, extraction, and separation of individual specimens. The respective mixtures of compounds after isolation are then analyzed via spectroscopic methods such as nuclear magnetic resonance spectroscopy, mass spectrometry, …

Chemistry And Biochemistry News, Georgia Southern University

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

• GSU Student Takes First Place for Research

Synthesis And Applications Of Graphene Oxide And Its Derivatives And Composites, Daoyuan Wang

Theses and Dissertations

Graphene oxide (GO), a monolayer of graphite oxide and an oxidized form of graphene, has attracted tremendous attention in the last decade due to its unique physical and chemical properties. This dissertation is devoted to three research areas: 1) The hydration behaviors of GO membranes, 2) The thermal reduction behaviors of GO membranes and the GO and reduced GO (RGO)-based filtration membranes for water purification, and 3) Photo- and electro-catalytic water splitting properties of GO-based derivatives and nanocomposites with other catalytic nanomaterials for hydrogen and oxygen production. 1) The hygroscopic nature of GO and the hydration behavior of trapped water …

Reducing Dynamic Disorder In Small-Molecule Organic Semiconductors By Suppressing Large-Amplitude Thermal Motions, Steffen Illig, Alexander S. Eggeman, Alessandro Troisi, Lang Jiang, Chris Warwick, Mark Nikolka, Guillaume Schweicher, Stephen G. Yeates, Yves Henri Geerts, John E. Anthony, Henning Sirringhaus

Chemistry Faculty Publications

Thermal vibrations and the dynamic disorder they create can detrimentally affect the transport properties of van der Waals bonded molecular semiconductors. The low-energy nature of these vibrations makes it difficult to access them experimentally, which is why we still lack clear molecular design rules to control and reduce dynamic disorder. In this study we discuss the promising organic semiconductors rubrene, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothio-phene and 2,9-di-decyl-dinaphtho-[2,3-b:20,30-f]-thieno-[3,2-b]-thiophene in terms of an exceptionally low degree of dynamic disorder. In particular, we analyse diffuse scattering in transmission electron microscopy, to show that small molecules that have their side chains attached along the long axis of their …