Chemistry Commons^™

Enhanced Corrosion Protection And Biocompatibility Of A Plga-Silane Coating On Az31 Mg Alloy For Orthopaedic Applications, Sankalp Agarwal, Muhammad Morshed, Marie-Noelle Labour, David Hoey, Brendan Duffy, James Curtin, Swarna Jaiswal

Articles

This paper reports a multi-step procedure to fabricate a novel corrosion resistant and biocompatible PLGA-silane coating on the magnesium (Mg) alloy AZ31. The first step involves alkaline passivation followed by dip coating in a methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) mixture to produce a cross-linked siloxane coating. The second step is to impart an amine functionalization to the silane modified surface by using 3-aminopropyl-triethoxy silane (APTES) for promoting adhesion of the acid terminated poly-(lactic-co-glycolic) acid (PLGA) as a final coating step. Static contact angle measurements, Fourier transform infrared spectroscopy and scanning electron microscopy analysis confirmed the successful assembly of coatings on …

Perchlorate Variations Over 300 Years: Influence Of Human Activities, Volcanic Eruptions And Bolide Events, Kari Peterson

Electronic Theses and Dissertations

Perchlorate, which derives from both anthropogenic and natural sources in the current environment, constitutes a significant health risk to humans because it competitively inhibits iodine uptake by the thyroid gland. Thus, there has been considerable interest in reducing the human exposure to environmental perchlorate by limiting the release of perchlorate from anthropogenic sources. However, a lack of understanding of the relative contributions from anthropogenic and natural sources has prevented widespread regulation. A 300-year ice core perchlorate record from Summit Station, Greenland (1700-2007 C.E.) that extends beyond the onset of the Industrial Revolution (1850 C.E.) is used to assess the anthropogenic …

Characterization Of Charge Accommodation In Biologically Important Hydrogen-Bonded Clusters, John Thomas Kelly

Electronic Theses and Dissertations

The underlying motivation of chemical physics and physical chemistry is to understand naturally occurring chemical and physical processes from the nanoscopic molecular level to the macroscopic condensed phase. Over the past half-century, experimentalists have developed a number of laser-based analytical techniques to bridge the gap between the bulk phase and the single molecule. Here, we look at bulk phase and gas phase clusters to compare the local hydrogen-bonded network. To better understand the role noncovalent interactions have on biologically relevant building blocks in a natural environment, we compare the microhydration of gas phase cluster ions to condensed phase spectra. The …

Raft Polymerization Of Ph-Responsive, Diblock Copolymers For Nucleic Acid Delivery Vehicles, Annie Katherine Mcclellan

Electronic Theses and Dissertations

Since the development of gene therapy, a variety of non-viral nucleic acid delivery vehicles have been prepared and studied for their transfection efficiencies. Recently, polymeric gene delivery vehicles have gained popularity for their low immunogenicity and high transfection efficiency. With the advent of controlled radical polymerization (CRP) and more specifically reversible addition-fragmentation chain transfer (RAFT) polymerization, it is now possible to develop well-defined polymers with predicted molecular weights and architectures. The work presented here focuses on the RAFT polymerization of a family of amphiphilic, cationic copolymers to be utilized for nucleic acid delivery. These copolymers are composed of a stabilizing …

Gas Exchange Of Hg Over Wetlands, Effect Of Biochar And Activated Carbon On Hg Emissions From Soil, And Seasonal Concentrations Of Hg In Rain, Divya Nallamothu

Electronic Theses and Dissertations

Mercury (Hg) is a global pollutant with human-health and ecological impacts. Gaseous Hg exchange between the atmosphere and aquatic or terrestrial surfaces serves as an important, but not well understood, route for Hg to enter and exit ecosystems. To better understand the role of gaseous Hg exchange in the biogeochemical cycling of Hg, we investigated Hg0 fluxes over natural wetlands (Sky Lake) and artificial wetlands (UM Field Station) using a dynamic flux chamber and an Hg vapor analyzer based on atomic fluorescence (Chapter 1). We also examined the effect of activated carbon and biochar on Hg emissions from soils for …

Gold And Silver Alloy Nanoparticles: Synthesis, Characterization And Atomic Structure, Chanaka Kapila Kumara

Electronic Theses and Dissertations

Nanotechnology is an emerging field of science with applications in digital electronics, medicine, catalysis and energy. Gold nanoparticles are nanomaterials that have less than 100 nm at least in one dimension. The composition and the structure/geometry of the nanoparticles determine the chemical properties and reactivity. Modern research focus on method development in atomically monodisperse nanoparticle synthesis. This dissertation describes the method development for synthesis and isolation of atomically precise gold and gold-silver alloy nanoparticles and their comprehensive characterization and atomic structure investigation. Chapter one offers an introduction to the synthesis and isolation methods. These nanoparticles can be represented in the …

Robust Nickel Catalysts Supported By Biaryl-Bridged Pyridyl-N-Heterocyclic Carbenes For Carbon Dioxide Reduction To Value-Added Products, Hunter Allen Dulaney

Electronic Theses and Dissertations

Carbon dioxide is a greenhouse gas, but also represents a readily accessible C1 feedstock for conversion to solar fuels and value-added chemicals. However, CO2 is relatively inert and very negative voltages or strong chemical reductants are comfor its conversion. An additional challenge lies in achieving these reactions in water where aqueous protons are utilized selectively for CO2 reduction rather than hydrogen generation. Our strategy for CO2 reduction involves the design of new homogeneous catalysts with tunable geometries and polyaromatic frameworks with increased delocalization to lower overpotentials for catalysis. We report a family of biaryl-bridged pyridyl-N-heterocyclic carbene-based ligands and their corresponding …

Investigation Of Neural And Epithelial Cadherin Monomer Properties Using A Molecular Dynamics Approach, Lianyi Fan

Electronic Theses and Dissertations

Neural and epithelial cadherin are adhesion proteins intensely studied by our lab. Although the sequence, structure, and conformation are similar for the two cadherins, there are several physical properties that differ: dimerization affinity, dimerization kinetics, intermediate structure, and critical residues for dimerization. In the presence of calcium, cadherins are in equilibrium between monomeric and dimeric states, and the scope of this thesis focuses on monomeric cadherin. These molecular dynamics evaluations are based on the testing of specific hypotheses regarding the intramolecular interactions of neural and epithelial cadherin. We particularly focus on interactions involving critical residues at the N-terminus of the …

Synthesis And Characterization Of Anhydrous Proton Conducting Polymer Electrolytes For Fuel Cell Applications, Buddika Mayomi Liyanage

Electronic Theses and Dissertations

Anhydrous H+ ion conducting and high temperature capability of polymer electrolytes are being investigated for use in applications such as batteries, fuel cells, electro chromic windows and light emitting devices. Fuel cells are efficient electrochemical energy conversion devices; they can generate greener energy from chemical fuels. The polymer electrolyte membrane is heart of most fuel cell designs separating the oxidant and fuel chambers and providing the medium to conduct H+ ions between the anode and the cathode. Our goal is to understand the molecular level details of anhydrous H+ conductivity through the synthesis and characterization of polymer electrolytes based on …

Synthesis And Characterization Of Transition Metal Phosphide Nanoparticles For Catalytic Applications: Model Catalysts For Hydrodesulfurization And Electrocatalysts For The Oxygen Evolution Reaction, Don Malinda Ruchira Liyanage

Wayne State University Dissertations

Transition metal phosphides are emerging as efficient catalysts for different processes. Although binary phases have been extensively studied recently researchers have explored the synergism afforded by bimetallic ternary transition metal phosphides. The conventional catalyst preparation methods (temperature programmed reduction or solvothermal synthesis) yield inhomogeneous samples, preventing a detailed understanding of how active site density impacts catalytic activity and mechanism. In contrast, solution-phase arrested-precipitation reactions produce uniform nanoparticles with an excellent control on size, morphology and composition.

This dissertation describes the synthesis of ternary transition metal phosphide nanoparticles (Ni2-xCoxP and Ni2-xRuxP) by solution-phase arrested-precipitation reactions and evaluation of their composition-dependent catalytic …

Facile Synthesis Of Tertiary Aliphatic Amine– Containing Cyclic Motif Via Neutral Aminyl Radical Cyclization, Heng Chen

Wayne State University Theses

Tertiary amine–containing cyclic motifs are prevalent in natural products and pharmaceutical lead targets. Inspired by these biological active molecules, one focus in our lab is the development of neutral aminyl radical chemistry in the synthesis of tertiary aliphatic amine–containing cyclic compounds. In this project, I investigated the mono- and tandem cyclization of aminyl radical with different types of olefins (terminal olefin, enone, and styrenyl). The effect of the hydrogen atom donor and the limitation of the reaction will be discussed.

In Vitro And In Vivo Measurments Of Serotonin For Ecological And Mental Health Via Fast Scan Cyclic Voltammetry, Matthew Nicholas Jackson

Wayne State University Theses

Fast Scan Cyclic Voltammetry has been proven to be a highly valuable technique in analysis and detection of neurotransmitters. With this technique, two novel applications are being explored to protect natural water sources as well as furthering the efficacy of antidepressants. Despite setbacks, promising data has been collected to further understand the mechanisms involved in the phototactic response observed in Daphnia Magna. Electrochemical modification of carbon fiber microelectrodes has proven to be inefficient as a means to effectively differentiate between serotonin and its metabolite. As such, this unsuccessful attempt has further narrowed down the list of candidates to electrochemically differentiate …

Targeted Delivery Of Nrf2 Sirna Using Modular Polymeric Micellar Nanodelivery System For Efficient Target Gene Knockdown In Hepatocellular Carcinoma, Shaimaa Mohamed Ibrahim Yousef

Wayne State University Theses

Tumor selective drug delivery as well as chemotherapy associated multi drug resistance (MDR) pose tremendous hurdles for effective cancer therapy. In this regard, designing multifunctional nanocarriers loaded with drug/gene payloads and engineered with tumor targeting ligands can serve as a modular platform for targeted drug/gene delivery. In this study we undertook the synthesis of a self-assembling block copolymer constructed using poly(styrene-co-maleic anhydride, partial iso-octyl ester) (SMAPIE) and branched polyethylenimine (PEI) as building blocks and evaluated its micelle forming ability, siRNA complexation and siRNA delivery potentials. In addition, we engineered galactosamine decorated nanomicelles using modular “click” chemistry based approaches for evaluating …

Hydrogen Bonding And Orientation Effects On The Accommodation Of Methylamine At The Air-Water Interface, Ross D. Hoehn, Marcelo A. Carignano, Sabre Kais, Chongjing Zhu, Xiao Cheng Zeng, Joseph S. Francisco, Ivan Gladich

Xiao Cheng Zeng Publications

Methylamine is an abundant amine compound detected in the atmosphere which can affect the nature of atmospheric aerosol surfaces, changing their chemical and optical properties. Molecular dynamics simulation results show that methylamine accommodation on water is close to unity with the hydrophilic head group solvated in the interfacial environment and the methyl group pointing into the air phase. A detailed analysis of the hydrogen bond network indicates stronger hydrogen bonds between water and the primary amine group at the interface, suggesting that atmospheric trace gases will likely react with the methyl group instead of the solvated amine site. These findings …

The Study Of Nf-Κb Peptide Mimics And How Proteins Bind Dna, Allee M. Murray

Honors College Theses

The protein complex nuclear factor kappa B (NF-κB) is widely considered to be one of the most influential transcription factors when studying cellular functions. Peptide mimics of NF-κB aim to inhibit DNA binding in order to displace the natural transcription factor, therefore inhibiting transcription and translation. In theory, NF-κB is not the problem; the real problem lies in directing the synthesis and expression of harmful proteins. In conjunction with this, the project aims to study NF-κB and its structure and function to determine what criteria are important for the binding of DNA in order to design a peptide that comes …

Synthesis And Characterization Of Cyclic Polypeptoids By Organo-Mediated Controlled Zwitterionic Ring-Opening Polymerization And Development Of Redox-Responsive Polypeptoid Micelles As Drug Delivery Carriers, Ang Li

LSU Doctoral Dissertations

Peptoids are peptidomimetic polymers, which have attracted much attention over the past two decades. They have similar building blocks to peptides, and the similarity makes the backbone of peptoids hydrophilic and biocompatible.1 Two types of peptoid polymers are under development. One is sequence-defined peptoids, which exhibit excellent bioactivities.2 Another one is polypeptoids. The good biocompatibility and highly tunable side chain substituents allow polypeptoids to be used broadly in future biomedical applications. Varying polymer architectures, including linear polymers, cyclic polymers, comb-like polymers, and dendrimers can provide distinctive properties to the polymers. Cyclic polymers employ a cyclic architecture and lack chain ends, …

A Disease Spectrum For Itpa Variation: Advances In Biochemical And Clinical Research, Nicholas E. Burgis

Chemistry and Biochemistry Faculty Publications

Human ITPase (encoded by the ITPA gene) is a protective enzyme which acts to exclude noncanonical (deoxy) nucleoside triphosphates ((d)NTPs) such as (deoxy)inosine 5′-triphosphate ((d)ITP), from (d)NTP pools. Until the last few years, the importance of ITPase in human health and disease has been enigmatic. In 2009, an article was published demonstrating that ITPase deficiency in mice is lethal. All homozygous null offspring died before weaning as a result of cardiomyopathy due to a defect in the maintenance of quality ATP pools. More recently, a whole exome sequencing project revealed that very rare, severe human ITPA mutation results in early …

Synthesis, Characterization, And Polymerization Of Sulfonamide Based Bifunctional Monomers, Brady Hall

Browse all Theses and Dissertations

A series of bifunctional monomers based on N,N-diallylbenzenesulfonamides with varying groups on the benzene moiety were investigated. The main goal of this project was to polymerize these monomers using radical and acyclic diene metathesis (ADMET) polymerization methods to polymerize through the allyl groups, and nucleophilic aromatic substitution (SNAr) to polymerize through the fluorine groups on the phenyl ring. Using phenyl substituted benzenesulfonyl chloride derivatives as a starting material, a series of N,N-diallylbenzenesulfonamide derivatives were prepared. The ADMET and radical cyclopolymerizations were monitored by 1H NMR spectroscopy, observing the disappearance of signals for the allyl groups in both, and the appearance …

Deterring Innovation: New York V. Actavis And The Duty To Subsidize Competitors' Market Entry, Joanna Shepherd

Faculty Articles

This Article examines a relatively new business strategy in the pharmaceutical market -- "product hopping" or "product replacement" -- in which brand pharmaceutical companies shift their marketing efforts from a drug nearing the end of its patent period to a new, substitute drug with a longer patent life. In July 2015, the Second Circuit issued an opinion in the first appellate case addressing pharmaceutical product replacement, New York ex rel. Schneiderman v. Actavis PLC. This Article explains that product replacement is the predictable business response to the incentives created by patent law and state substitution laws, and withdrawing an …

Uv Light-Induced Aggregation Of Titania Submicron Particles, Can Zhou, Yashar Bashirzadeh, Timothy A. Bernadowsky Jr., Xiaoyu Zhang

Mechanical & Aerospace Engineering Faculty Publications

In this study, aggregation of TiO₂ (rutile and anatase) submicron particles in deionized (DI) water under ultra-violet (UV) light irradiation was investigated. While no aggregation was observed in the dark, rutile and anatase submicron particles started aggregating upon application of UV light and ceased aggregation in about 2 and 8.4 h, respectively. It has been demonstrated that UV light directly mitigated the particle mobility of TiO₂, resulting in a neutralization effect of the Zeta potential. It was also observed that rutile particles aggregated much faster than anatase particles under UV radiation, indicating that the Zeta potential of …

Carinata Fame Production Process And Biofuel Oxidation, Benoit Kindo

Honors College Theses

In this experiment, the contribution of a standard production method for biofuels on their oxidative stability was investigated. Peroxide values were measured at different steps of the production process of Brassica carinata and peanut-based biofuels. The washing and drying steps in this production method showed significant increases in peroxide values for both biofuels and was identified as a major contributor of biofuel oxidation. Further analyses of the physical and thermal properties showed a more pronounced affect in the biofuel from Bassica carinata, and indicated an unusual composition much higher in saturated fatty acids much longer than those found in peanut. …

Effects Of Citric Acid Coated And Uncoated Cerium Oxide Nanoparticles In Tomato (Solanum Lycopersicum) Plants, Ana Cecilia Barrios

Open Access Theses & Dissertations

This research was performed to examine the physiological and biochemical effects of bare (nCeO2) and citric acid coated (nCeO2+CA) cerium oxide nanoparticles in tomato (Solanum lycopersicum). Plants were germinated and grown to full maturity in soil amended with 0-500 mg/kg and periodically analyzed using ICP-OES/MS and other spectroscopic and biochemical techniques. Although Ce in tissues increased as the external nCeO2 increased, there were no visible signs of toxicity. In mature plants, nCeO2 induced developmental changes and altered nutritional quality (essential elements) in fruits. On the other hand, nCeO2+CA affected fruit carbohydrate composition (sugars and starch). This study gives insights on …

Improving The Engineering Properties Of Pla For 3d Printing And Beyond, Carmen R. Rocha

Open Access Theses & Dissertations

Additive manufacturing (AM), now more commonly known as 3D printing, has been classified as efficient, fast, and practical in the prototyping sector of product development. In the work presented here, we will use one of the AM techniques known as Material extrusion 3D printing (ME3DP), which has all the advantages of AM. However, one of the biggest challenges facing ME3DP technologies is the limitation of the range of materials used by this technique. Acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA) are currently the most common thermoplastics materials used in ME3DP because of their ability to melt and be reprocessed. …

Talking Through The Problems: A Study Of Discourse In Peer-Led Small Groups, Michelle D. Repice, R. Keith Sawyer, Mark C. Hogrebe, Patrick L. Brown, Sarah Luesse, Daniel J. Gealy, Regina F. Frey

SIUE Faculty Research, Scholarship, and Creative Activity

Increasingly, studies are investigating the factors that influence student discourse in science courses, and specifically the mechanisms and discourse processes within small groups, to better understand the learning that takes place as students work together. This paper contributes to a growing body of research by analyzing how students engage in conversation and work together to solve problems in a peer-led small-group setting. This qualitative study evaluates video of Peer-Led Team Learning (PLTL) sessions in general chemistry, with attention to both the activity structures and the function of discourse as students undertook different types of problems across one semester. Our findings …

Determination Of Mln0128, An Investigational Antineoplastic Agent, In Human Plasma By Lc–Ms/Ms, Sandeep R. Kunati, Yan Xu

Chemistry Faculty Publications

MLN0128, an mTOR kinase inhibitor, is currently undergoing clinical investigation for treatment of a variety of cancers. To support this work, an LC–MS/MS method has been developed for the determination of MLN0128 in human plasma. A structural analog STK040263 was used as the internal standard. Both MLN0128 and the IS were first extracted from plasma using methyl tert-butyl ether; then separated on a Waters XTerra® MS C18 column using a mobile phase consisting of methanol–acetonitrile–10.0 mm ammonium formate (34:6:60, v/v/v) at a flow rate of 0.300 mL min−1. Quantitation of MLN0128 was done by positive electrospray ionization tandem mass spectrometry …

Effect Of Synthesis On Quality, Electronic Properties And Environmental Stability Of Individual Monolayer Ti3C2 Mxene Flakes, Alexey Lipatov, Mohamed H. Alhabeb, Maria R. Lukatskaya, Alex J. Boson, Yury Gogotsi, Alexander Sinitskii

Department of Chemistry: Faculty Publications

2D transition metal carbide Ti₃C₂T_x (T stands for surface termination), the most widely studied MXene, has shown outstanding electrochemical properties and promise for a number of bulk applications. However, electronic properties of individual MXene flakes, which are important for understanding the potential of these materials, remain largely unexplored. Herein, a modified synthetic method is reported for producing high-quality monolayer Ti₃C₂T_x flakes. Field-effect transistors (FETs) based on monolayer Ti₃C₂T_x flakes are fabricated and their electronic properties are measured. Individual Ti₃C₂T_x flakes …

Plasma Temperature Measurements In The Context Of Spectral Interference, Brandon Seesahai

Honors Undergraduate Theses

The path explored in this thesis is testing a plasma temperature measurement approach that accounts for interference in a spectrum. The Atomic Emission Spectroscopy (AES) technique used is called Laser Induced Breakdown Spectroscopy (LIBS) and involves focusing a laser pulse to a high irradiance onto a sample to induced a plasma. Spectrally analyzing the plasma light provides a "finger print" or spectrum of the sample. Unfortunately, spectral line broadening is a type of interference encountered in a LIBS spectrum because it blends possible ionic or atomic transitions that occur in plasma. To make use of the information or transitions not …

Degradation Of Hexachlorobenzene, Pentachlorophenol And Pentachloroanisole Using Activated Magnesium In An Acidified Ethanol/Ethyl Lactate Cosolvent System, Amel Garbou

Electronic Theses and Dissertations

For many centuries, chemists have dedicated many labor-intensive hours to improving the quality of life for mankind by developing synthetic methods for the production of compounds which fulfill the needs and meet the demands of society. However, the innovation of such compounds has frequently come at the cost of detrimental side-effects that do not always present themselves until many years, or even decades, following their initial application. Many compounds in this category come in the form of globally-distributed halogenated molecules which are toxic to many living organisms, susceptible to bioaccumulation and resistant to biodegradation processes. Such compounds are classified as …

Analysis Of Benzopyrenes And Benzopyrene Metabolites By Fluorescence Spectroscopy Techniques, Bassam Al-Farhani

Electronic Theses and Dissertations

Polycyclic aromatic hydrocarbons (PAHs) are some of the most common and toxic pollutants encountered worldwide. Presently, monitoring is restricted to sixteen PAHs, but it is well understood that this list omits many toxic PAHs. Among the "forgotten" PAHs, isomers with molecular weight 302 are of particular concern due to their high toxicological properties. The chromatographic analysis of PAHs with MW 302 is challenged by similar retention times and virtually identical mass fragmentation patterns. The first original component of this dissertation evolves from a high-resolution spectroscopic approach specifically developed to fulfil this gap. Herein, 4.2 K Laser-Excited Time-Resolved Shpol'skii Spectroscopy (4.2K …

Nucleophile Promoted Gold Redox Catalysis With Diazonium: Cbr, C-S And C-P Bond Formation Through Catalytic Sandmeyer Coupling, Haihui Peng, Rong Cai, Chang Xu, Hao Chen, Xiaodong Shi

Faculty & Staff Scholarship

Gold-catalyzed C-heteroatom (C-X) coupling reactions are evaluated without using sacrificial oxidants. Vital to the success of this methodology is the nucleophile-assisted activation of aryldiazonium salts, which could be an effective oxidant to convert Au(I) to Au(III) even without the addition of assisting ligand or photocatalyst. By accelerating reaction kinetics to outcompete C-C homo-coupling or diazonium dediazoniation, gold-catalyzed Sandmeyer reactions were achieved with different nucleophiles, forming C-Br, C-S and C-P bonds in high yields and selectivity.