Chemistry Commons^™

Catalytic Conversion Of Monosaccharides Into 5-(Hydroxymethyl)Furfural In Ionic Liquids Using Aluminum Complexes Bearing Bidentate (Aminomethyl)Phenolate Ligands, Daudi Sayialel Saang'onyo

Theses and Dissertations--Chemistry

Currently, the major sources of fuel, energy, and chemicals are nonrenewable fossil resources such as petroleum, natural gas, and coal. Additionally, petroleum is used for the production of most transportation fuels and for the production of about 95% of organic chemicals. However, the production and use of non-renewable fossil fuels are unsustainable. For economic and environmental sustainability, there is a need to search for new and/or renewable resources and technologies for energy, fuels, and chemicals production that have the potential of effectively substituting fossil resources. In this context, lignocellulosic biomass is one of the candidates that meet these requirements due …

Aqueous Photochemistry Of 2-Oxocarboxylic Acids, Alexis Eugene

Theses and Dissertations--Chemistry

Atmospheric aerosols affect climate change by altering the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosol (SOA) from gas phase precursors is relatively well understood, it does not account for the abundance of SOA observed during field measurements. Recently it has become apparent that in-aerosol aqueous chemical reactions likely provide some of the missing sources of SOA production, and many studies of aqueous phase processes are underway.

This work explores the fates of the simplest 2-oxocarboxylic acids, glyoxylic acid (GA) and pyruvic acid (PA), …

Evaluation Of Autonomously Measured Alkalinity, Ph, And Pco2 Variability On A Coral Reef, Brittany Peterson

Graduate Student Theses, Dissertations, & Professional Papers

Currently, our understanding of alkalinity (A_T) variability in highly dynamic environments such as coral reefs is limited by the dearth of A_T measurements. In order to better characterize these environments, high temporal resolution A_T data are needed. This work employed the newly developed Submersible Autonomous Moored Instrument for Alkalinity (SAMI-alk), a fully autonomous in situ A_T analyzer, to study seawater A_T variability. The main goals of this research were to evaluate the utility of combining the SAMI-alk data with currently available in situ measurements of pH and partial pressure of carbon dioxide (p …

Relationships Among Vitamin D Deficiency, Metabolic Syndrome, Smoking Behavior, And Physical Activity, Ethan Pham

Walden Dissertations and Doctoral Studies

Aging increases the risk of both vitamin D deficiency and metabolic syndrome. Vitamin D deficiency and metabolic syndrome may be related, although there are mixed findings. Furthermore, literature suggests other factors such as physical fitness activity and smoking behavior are associated with Vitamin D deficiency and the development of metabolic syndrome. A number of studies have documented associations between Vitamin D levels and physical fitness activities, while other studies found correlations between Vitamin D levels, metabolic syndrome, and smoking behavior. However, no previous study has examined the links between physical fitness activity, smoking behavior, Vitamin D levels, and the risks …

Part I: Design, Synthesis, And Studies Of Novel Age-Inhibitors And Age-Breakers; Part Ii: Novel Synthetic Methods For Organofluorine Compound, Jatin Mehta

Doctoral Dissertations

"Novel small molecule inhibitors and breakers of advanced glycation end-products (AGEs) have been synthesized and their in vitro inhibitory activities have been studied by ¹³C NMR, fluorescence, and UV-visible spectroscopy. We have demonstrated that these AGE-inhibitors and AGE-breakers were found to be more effective in their sequestration of AGE intermediates, such as dehydroascorbate (DHA) than the state-of-the art phenacylthiazolium bromide (PTB)-based AGE-inhibitors and AGE-breakers. Citric acid and other polyphenolic antioxidants have substantial AGE inhibitory effects in the D-glucose/leucine or benzylamine Maillard reaction model systems, and thus they are suitable as dietary additives for ameliorating AGE-induced complications.

Organofluorine compounds have …

Heteroatom Doped Porous Carbon For Alternative Energy Conversion And Storage Systems, Fatema A. Choudhury

Theses and Dissertations

Abstract

The electrocatalysis of oxygen plays a significant role in several electrochemical energy storage and conversion systems including metal−air batteries, fuel cells, electrocatalytic and photocatalytic water splitting. The sluggish kinetics and complex reaction mechanism of this cathodic oxygen reduction reaction (ORR) affect the performance and practical application of such renewable energy technologies. To address this limiting factor, a suitable electrocatalyst is required for ORR. In general, platinum or highly dispersed Pt-based nanoparticles on carbon black are considered as the best ORR catalyst. But platinum being very scarce and expensive tends to increase the cost. Moreover, platinum-based catalysts are prone to …

Development, Manufacture And Application Of A Solid-State Ph Sensor Using Ruthenium Oxide, Wade Lonsdale

Theses: Doctorates and Masters

The measurement of pH is undertaken frequently in numerous settings for many applications. The common glass pH probe is almost ideal for measuring pH, and as such, it is used almost ubiquitously. However, glass is not ideal for all applications due to its relatively large size, fragility, need for recalibration and wet-storage. Therefore, much research has been undertaken on the use of metal oxides as an alternative for the measurement of pH.

Here, a solid-state potentiometric pH sensor is developed using ruthenium metal oxide (RuO2). Initially, pH sensitive RuO2 electrodes were prepared by deposition with radio frequency magnetron sputtering (RFMS) …

Detection Of Cyanotoxins (Microcystins/Nodularins) In Hepatic Tissues And Epidermal Mats Of Stranded Bottlenose Dolphins (Tursiops Truncatus) In Northeast Florida, Amber Brown

UNF Graduate Theses and Dissertations

The St. Johns River (SJR; Jacksonville, FL, USA) is a large, brackish, estuarine system characterized by considerable anthropogenic pollution, recurrent harmful algal blooms (HABs), and diverse toxin-producing cyanobacteria. The most prevalent toxins in SJR water samples are microcystins/nodularins (MCs/NODs). Additionally, the SJR provides critical habitat for a genetically and behaviorally distinct estuarine community of bottlenose dolphins (Tursiops truncatus) that routinely uses and strands in low mesohaline and oligohaline areas of the river. This population has been subject to two unusual mortality events (UME) since 2010 and has since been described as having substantial declines in population health, characterized …

Capacity Fading Analyses Of Lini0.5Co0.2Mn0.3O2And Lini0.5Co0.2Mn0.3O2/Lifepo4 Cathode Materials For Lithium-Ion Battery, Yi Hu, Xiang-Zhu He, Zhong-De Deng, Ling-Yong Kong, Wei-Li Shang

Journal of Electrochemistry

The LiNi _0.5Co _0.2Mn _0.3O₂/LiFePO₄ (NMC532/LFP) composite cathode material for lithium-ion battery was prepared by wet ball-milling. The capacity fading behaviors of LiNi _0.5Co _0.2Mn _0.3O₂ (NMC532) and LiNi _0.5Co _0.2Mn _0.3O₂/LiFePO₄ (NMC532/LFP) were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), charge/discharge and electrochemical impedance spectroscopy (EIS) tests. The results indicated that the capacity retention values of NMC532/LFP were 97.80% and 86.48%, respectively, after 50 cycles and 60℃ high temperature storage. The NMC532/LFP exhibited better cycle performance and high temperature storage performance. …

Testing The Underlying Chemical Principles Of The Biotic Ligand Model (Blm) To Marine Copper Systems: Measuring Copper Speciation Using Fluorescence Quenching, Tara N. Tait, James C. Mcgeer, Scott Smith

Chemistry Faculty Publications

Speciation of copper in marine systems strongly influences the ability of copper to cause toxicity. Natural organic matter (NOM) contains many binding sites which provides a protective effect on copper toxicity. The purpose of this study was to characterize copper binding with NOM using fluorescence quenching techniques. Fluorescence quenching of NOM with copper was performed on nine sea water samples. The resulting stability con- stants and binding capacities were consistent with literature values of marine NOM, show- ing strong binding with log K values from 7.64 to 10.2 and binding capacities ranging from 15 to 3110 nmole mg C ^{−1 …}

Multivariate Statistical Analyses Of Air Pollutants And Meteorology In Chicago During Summers 2010–2012, Katrina Binaku, Martina Schmeling

Chemistry: Faculty Publications and Other Works

Aerosol, trace gas, and meteorological data were collected in Chicago, Illinois during 2010–2012 summer air studies. Ozone, nitrogen oxides, acetate, formate, chloride, nitrate, sulfate, and oxalate concentrations as well as temperature, wind speed, wind direction, and humidity data were explored by both principal component analysis (PCA) and canonical correlation analysis (CCA). Multivariate statistical techniques were applied to uncover existing relationships between meteorology and air pollutant concentrations and also reduce data dimensions.

In PCA, principal components (PC) revealed a relationship of ozone and nitrate concentrations with respect to temperature and humidity, coupled with transport of species from the south in relation …

The Electrochemical Deposition Of Samarium And Europium Dissolved In Ionic Liquid Solvent, Bea Martinez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rare-earth elements include the lanthanide series in the periodic table with the addition of scandium and yttrium. China produces approximately 95% of the world’s rare-earths supply and is the largest consumer of the world’s rare earth supply. Domestic production of rare-earth metals is a priority in the US. The domestic demand for rare-earth elements is largely based on their use in electronic devices, catalytic converters, and more importantly defense applications. Therefore, China’s monopoly of rare-earth elements is viewed as a threat to national security. Although capital investments have resulted in an increase in domestic mining and refining of rare-earth materials, …

Bioinformatic And Biophysical Analyses Of Proteins, Jonathan Catazaro

Department of Chemistry: Dissertations, Theses, and Student Research

The prevailing dogma in structural genomics is the existence of a strong correlation between protein sequence, structure, and biological function. Proteins with high sequence similarity typically have a similar, if not the same, structure and function. In many cases this logic can fail due to distantly related proteins having very low sequence similarity, a lack of a representative structure, structural novelty, or the absence of a characterized function. Further, the paradigm fails to account for dynamics, which have a significant effect on structural stability and enzymatic efficacy.

Nuclear magnetic resonance (NMR) spectroscopy is uniquely capable of solving the structure, assisting …

Expression, Purification And Characterization Of Egf27 From The Notch1 Abruptex Region, Huimin Zhong

LSU Master's Theses

Notch proteins are transmembrane proteins and act as receptors in Notch signaling, which is related to diverse developmental diseases including cancer.^1-2 The mouse Notch1 protein contains 36 tandem epidermal growth factor-like (EGF) repeats in the extracellular domain (ECD).^1-2 Our research project focused on the structural study of the Abruptex region consisting of EGF24-29 in the ECD. The fact that this region is a potential competitor to a Notch ligand, because of its high glycosylation and flexibility, makes it important to solve the three-dimensional structure and investigate the glycosylation effect on the structure of the Abruptex region.³ By …

Sol-Gel Niobia-Based Sorbents For The Enrichment Of Organophosphorus Compounds By Capillary Microextraction Online Coupled To High Performance Liquid Chromatography, Sheshanka Kesani

USF Tampa Graduate Theses and Dissertations

Sample preparation is a key step in chemical analysis, and includes isolation of target analytes, removal of interferences, preconcentration, and/or modification of target analytes (if needed). Sample preparation is also the most time-consuming and error-prone step in the whole analytical process. Traditional sample preparation techniques involve hazardous solvents. Considering the environmental and health safety, it is desirable to reduce or eliminate organic solvents in sample preparation. Solid phase microextraction (SPME) was introduced as a solvent free sample preparation technique. Capillary microextraction (CME) is one of the formats of SPME that can be easily coupled to high performance liquid chromatography (HPLC). …

Nanopatterns Of Zinc Phthalocyanines, Gold Nanoparticles, And Porphyrins Prepared Using Particle Lithography: Characterization Of Patterning Steps With Scanning Probe Microscopy, Ashley Marie Taylor

LSU Doctoral Dissertations

The growth and self-assembly of molecules on surfaces can be directly visualized at the molecular level using studies which combine nanoscale lithography and high-resolution imaging. Nanopatterning provides a unique and practical approach for direct views of surface changes after the key chemical steps of nanopatterning, providing landmarks and baselines for measuring growth in vertical and lateral dimensions. Controlling the arrangement of materials on surfaces at the nanoscale can be achieved using particle lithography. Arrays of well-defined nanostructures can be prepared with reproducible geometries and arrangement. Results for the preparation of nanopatterns produced with particle lithography are presented using high resolution …

Self-Assembly Mechanisms Of Organosilanes And Porphyrins Investigated With Scanning Probe Microscopy, Phillip Charles Chambers Ii

LSU Doctoral Dissertations

This dissertation details the development of new fabrication strategies for the preparation of spatially selective surfaces by combining techniques of particle lithography and scanning probe microscopy (SPM). This combination of lithography and nanoscale surface characterization was applied to study the mechanisms of molecular level surface-assembly of organosilanes and porphyrin on surfaces of Si(111). Particle lithography was used to investigate the surface assembly of 4-chloromethylphenyltrichlorosilane (CMPS) within exposed sites of nanoholes in selected solvents and at selected temperatures to gain insight into the details of self-polymerization. Nanopillars of CMPS were generated under selected conditions of solvent and temperature and characterized with …

Unmanned Aerial Systems For Monitoring Trace Tropospheric Gases, Travis J. Schuyler, Marcelo I. Guzman

Chemistry Faculty Publications

The emission of greenhouse gases (GHGs) has changed the composition of the atmosphere during the Anthropocene. Accurately documenting the sources and magnitude of GHGs emission is an important undertaking for discriminating the contributions of different processes to radiative forcing. Currently there is no mobile platform that is able to quantify trace gases at altitudes(UASs) can be deployed on-site in minutes and can support the payloads necessary to quantify trace gases. Therefore, current efforts combine the use of UASs available on the civilian market with inexpensively designed analytical systems for monitoring atmospheric trace gases. In this context, this perspective introduces the …

Spectral Characterization Of Cytochromes P450 Active Sites Using Nmr And Resonance Raman Spectroscopy, Remigio Usai

Dissertations (1934 -)

The Cytochrome P450 (P450s) has been the subject of intense research for over six decades. An efficient approach for isotopic labeling of the prosthetic group in heme proteins was exploited to produce an analogue of the soluble bacterial cytochrome P450cam (P450cam) that contains a 13C labeled-protoheme prosthetic group. HU227 strain of E. coli, which lacks the δ-aminolevulinic acid (δ-ALA) synthase gene, was employed in the heterologous expression of P450cam harboring a prosthetic group labeled with 13C at the Cm and Cα positions by growing cells in the presence of [5-13C] δ-ALA, which was synthesized in four steps from [2-13C] glycine. …

Distinct Ice Patterns On Solid Surfaces With Various Wettabilities, Jie Liu, Chongqin Zhu, Kai Liu, Ying Jiang, Yanlin Song, Joseph S. Francisco, Xiao Cheng Zeng, Jianjun Wang

Xiao Cheng Zeng Publications

No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions and the discovery of two growth modes of ice crystals: along-surface and off-surface growth modes. Using atomistic molecular dynamics simulation analysis, we show that these distinct ice growth phenomena are attributable to the presence (or absence) of bilayer ice on solid surfaces with different wettability; that is, the formation of …

Development And Validation Of A Novel Lc–Ms/Ms Method For Simultaneous Determination Of Abiraterone And Its Seven Steroidal Metabolites In Human Serum: Innovation In Separation Of Diastereoisomers Without Use Of A Chiral Column, Mohammad Alyamani, Zhenfei Li, Sunil K. Upadhyay, David J. Anderson, Richard J. Auchus, Nima Sharifi

Chemistry Faculty Publications

Abiraterone acetate (AA), the prodrug of abiraterone, is FDA-approved for the treatment of castration-resistant prostate cancer. Abiraterone is metabolized in patients to a more potent analogue, D4A. However, we have recently reported that this analogue is further metabolized to additional metabolites in patients treated with AA. Here, we present a liquid chromatography-tandem mass spectrometry method developed to resolve and detect abiraterone and its seven metabolites in human serum using an AB Sciex Qtrap 5500 mass analyzer coupled with a Shimadzu Nexera UPLC station. Analytes and the internal standard (abiraterone-d4) were extracted from human serum using the liquid–liquid extraction procedure. The …

Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2 And O2 Adsorption: A Dft Analysis, Jingyun Ye, Tianyu Zhang, Lingyun Xu, Shuxia Yin, Krishanthi Weerasinghe, Pamela Ubaldo, Ping He, Qingfeng Ge

Journal of Electrochemistry

Transition metal carbides and nitrides are attractive materials for electrodes in many electrochemical energy storage and conversion applications. In the present study, we use density functional theory slab calculations to characterize the surface chemical properties of molybdenum (Mo) and tungsten (W) carbides and nitrides, namely, Mo₂C, W₂C, Mo₂N and W2N with the adsorption of CO, CO₂ and O₂. These probing molecules provide measures of in both acidity/basicity and redox property of for the surfaces of these carbides and nitrides. Our results show that Lewis basic sites were responsible for CO_{2 …}

Geochemical Fractionation, Speciation, And Bioavailability Of Heavy Metals In Stream Sediments In Aurora, Mo, Miles Pearson

Graduate Theses/Dissertations

Stream sediments from Chat Creek in Aurora, MO, part of the former Tristate Mining District, were digested via a sequential extraction procedure modeled after the Tessier method. Prior sampling had shown elevated levels of zinc, lead, and cadmium in sediments located near former chat piles. Metals in sediments were divided into four geochemical fractions: 1) easily exchangeable, 2) carbonate-bound, 3) iron-manganese oxides-bound, and 4) organic matter-bound. The distribution of the metals within these fractions can help predict the bioavailability and speciation of said metals. The majority of metals were contained in the third and to a lesser extent the fourth …

Investigating Hydrothermal And Radiation Effects On Nitrogen Heterocycles Relevant To Meteorite Parent Bodies, Phillip G. Hammer

Boise State University Theses and Dissertations

Organic compounds in meteorites were likely transformed by a variety of processes on the asteroid parent body including aqueous, thermal, and radiolytic alteration. Previous studies have identified a suite of purine nitrogen heterocycles in carbonaceous chondrites (a class of meteorites) and determined that their likely origin was due to cyanide chemistry. The thesis research described here consisted of two parts: investigating thermal effects on aqueous ammonium cyanide reactions and the production/survivability of organics (Chapter 2) and investigating gamma radiation effects on purine nitrogen heterocycles to understand how prolonged radiation exposure influenced the distribution and abundance of nitrogen heterocycles measured in …

Electrogenerated Chemiluminescent Studies Of 9,10-Diphenylanthracene, Rubrene, Tris(2,2'-Bipyridine)Ruthenium(Ii) Species, And Their Derivatives For Sensitive Detection Of Biomolecules, Pradip Bastola

Dissertations

This dissertation explored and investigated the coreactant electrogenerated chemiluminescent (ECL) properties of unmixed and mixed systems of highly efficient ECL emitters, such as 9,10-diphenylanthracene (DPA), rubrene (RUB), and tris(2,2′-bipyridine)ruthenium(II) [(Ru(bpy)₃²⁺)] species as well as their water-soluble derivatives, which can serve as ECL labels for sensitive bioanalysis of single or multiple analytes. The screening of most favorable common ECL coreactants, their concentration effects along with the effect of working electrode materials on ECL behavior, and energy transfer related interactions between ECL emitters were systematically investigated. In addition, a strategy for improvement of ECL signals with the use of …

Anodic Nanocatalysts For Formic Acid Fuel Cells: An Electrochemical Study, Tamanna F. Shanta Mcfarland

Dissertations

Direct formic acid fuel cells (DFAFCs) have been reported as a prominent source of alternative green energy and solution to imminent energy crisis for the last two decades. The challenge to commercialize DFAFCs is primarily the utilization of cost effective, high performance and durable anodic catalyst for formic acid oxidation (FAO). Consequently, this dissertation addresses the extensive electrochemical study of a number of nanomaterials towards the potential use as electrocatalysts for FAO. Morphology and elemental analyses of the prepared nanomaterials were obtained using electron microscopy techniques.

After a general introduction and overall review of this dissertation (Chapter I), studies of …

Controlled Electrochemical Synthesis Of Single One-Dimensional Metal Nanochains Across Microgap Electrodes., Amareshwari Konutham

Electronic Theses and Dissertations

This study mainly focuses on the fabrication of single one dimensional (1D) NP chains across the 5-micron gap of Au two electrode devices (TED). This has been achieved by electrochemical deposition of Ag onto the two electrodes, soaking the TED in 0.1 M Cetyltrimethyl ammonium bromide for 2-3 hours, and then close monitoring of the current as a function of time while a voltage across the two Ag coated Au electrodes in air. One dimensional Ag nanoparticle chain formation occurred by oxidation of Ag to Ag⁺ at the positive electrode followed by movement of Ag⁺ ions to the …

Instrumental Aspects Of Oxygen Sensing: Quantitation And Recalibration Of A Biofouled Oxygen Sensor, Marlena Patrick

Graduate Theses and Dissertations

In vivo oxygen sensing is a critical area of research for medical applications, such as ischemic stroke, but this important topic is not fully understood or resolved. In addition, the best method for calibration of in vivo sensors is as yet undetermined. For all implantable devices, biofouling, the adsorption of biological material to the device surface, is another significant problem with no clear or well-defined solution. One method employed is to apply a protective polymer membrane to the sensor surface in order to minimize the adsorption of biological material. The work described here investigates two polymers applied to a gold …

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 …