Chemistry Commons^™

New Adaptations Of Analytical Tools For The Study Of Dynamic Interactions Of Lanthanide-Based Catalysis In Aqueous Media, Prabani Lakmanthi Dissanayake

Wayne State University Dissertations

Lewis acid catalyzed carbon-carbon bond-forming reactions are of great interest in organic synthesis. However, many conventional Lewis acids, and almost all enantioselective Lewis acid catalysts, must be used under strictly anhydrous conditions to avoid hydrolysis and the difficulties associated with recovery and reuse of the catalysts. Due to these drawbacks of conventional Lewis acids, there is a growing desire to perform many organic transformations using more environmentally friendly aqueous-stable catalysts. The advantages of using aqueous-stable catalysts include the ability to use unprotected functional groups, ease of product separation and catalyst recovery, and avoidance of costly solvent drying procedures. Lanthanide trifluoronmethanesulfonates …

Exploring Conformational Variability Of An Rna Domain In The Ribosome: From Structure And Function To Potential Antibiotic Targeting, Yogo Sakakibara

Wayne State University Dissertations

RNA in nature is modified at many specific sites to order to gain extra functions or to expand the genetic code. One of such RNAs is ribosomal RNA (rRNA), which contains several modified bases, particularly around the functionally significant sites. We have focused on understanding the influences of modified base on RNA structure and function by employing helix 69 (H69), which is a good region to evaluate the roles of modified bases since it contains three pseudouridines in the loop region and exists at the core of the ribosome.

Previous model studies using small hairpin H69 showed the conformational differences …

Analysis Of Illicit Drugs, Their Metabolites And Other Micropollutants In Water By Liquid Chromatography Tandem Mass Spectrometry, Deepika P. Panawennage

Dissertations

The goal of this project is to develop liquid chromatography tandem mass spectrometry (LC/MS/MS) methods for the analysis of different, novel micropollutants in waste water and natural water. Micropollutants are compounds that can exert adverse environmental and human health effects at low concentrations. Most of these compounds include personal care products and pharmaceuticals, such as antibiotics and controlled substances. In the first part of this study, we focused in the analysis of illicit drugs and drug metabolites because these analyses have the potential to serve as markers of drug abuse. We have detected over sixteen different illicit drugs and their …

Spectroelectrochemical Studies Of The Reductive Intermediates Of Anthraquinone-2,6-Disulfonate In Aqueous Media, Anna Weiss

Dissertations

Reactive intermediates in the reduction of anthraquinone-2,6-disulfonate (AQDS) by dithionite combine to form a transient dimer which has shown to give rise to a series of charge transfer bands in the visible range (600-750 nm). Additional wavelengths associated with these intermediate species have been observed at wavelengths 402, 444 and 510 nm. These transient intermediates are generated as dithionite decomposition products re-oxidize AQDS. Evidence of the dimer was also found in experiments in which reduction of AQDS was achieved electrochemically by the use of a potentiostat. This implies three things: 1. dithionite is not required for dimerization of reactive intermediates; …

Deuterium Tracer Studies Of The Mechanism Of Cobalt Catalyzed Fischer-Tropsch Synthesis, Chunfen Jin

Online Theses and Dissertations

Since the Fischer-Tropsch (FT) catalytic polymerization reaction has been discovered in 1920s, many kinds of possible mechanisms have been reported. However, there is still debate because there is a lacking of experimental evidence to discriminate the validity of each mechanism. To define the mechanism of Fischer-Tropsch-Synthesis (FTS), we must define the C-C formation pathways as well as the structure of initiator species in the process, and finally provide an explanation in mechanistic detail as to how branched hydrocarbon compounds are formed in the reaction sequence.

In order to understand the cobalt catalyzed mechanism of FTS, we conducted H2/D2 switching and …

Synthesis Of Novel Ionic Liquid Tagged Porphryin Media Designed For The Oxidation Of Lignin, Joseph Hugh Franklin Baker

Online Theses and Dissertations

The ever growing need for a viable renewable fuel source has led to this thesis project; the biomimetic lignin degradation by means of a homogeneous oxidative catalyst in corresponding ionic liquids. Lignin comprises nearly a third of lignocellulosic biomass and is cross-linked to both cellulose and hemicellulose. Current utilization methods of lignin do not generate the full value of the polymer, because they do not yield many of the valuable feed stock chemicals it is comprised of. To improve the value of the biomass as a whole and create a viable economy for the US's transition to biofuels, better utilization …

Ambient Ionization Mass Spectrometry Analysis Pertaining To Biofuel Process Development, Sushma Dendukuri

Online Theses and Dissertations

Mass spectrometry (MS) has undergone a revolution with the introduction of a new group of desorption/ionization (DI) techniques known collectively as Ambient Ionization mass spectrometry. Ambient ionization mass spectrometry allows for direct analysis of analytes and typically requires little or no sample preparation. Specifically, Direct Analysis in Real Time (DART) has developed rapidly and allowed investigations to occur with the analysis of biomass after various pretreatments to determine the pretreatment biomass degradation efficiency. The degradation of the initial biomass structure is a very important step before other chemical treatments can occur to generate needed sugars. Since generated sugars aid in …

Profiles In Science: John Bennett Fenn, Kimberly Brady, Roy Brown, Emily Johnson, Shannon D. Jones, Margaret Henderson, Dana Ladd, Irene Lubker, Jennifer A. Mcdaniel

VCU Libraries Faculty and Staff Publications

“Don’t ever try to be a scientist or engineer!” Had John Bennett Fenn listened to this advice given by his ninth grade teacher, he might not have gone on to pursue a career in analytical chemistry which would culminate in the attainment of the Nobel Prize in 2002. Gathered from interviews, publication analyses, glowing tributes, and his reminiscences, this paper outlines the academic and professional life of John Fenn from childhood through the end of his career in 2010.

Comparisons Of Observed And Modeled Oh And Ho2 Concentrations During The Ambient Measurement Period Of The Ho(X)Comp Field Campaign, Y. Kanaya, A. Hofzumahaus, H. -P. Dorn, T. Brauers, H. Fuchs, F. Holland

USF St. Petersburg Campus Faculty Publications

A photochemical box model constrained by ancillary observations was used to simulate OH and HO2 concentrations for three days of ambient observations during the HO(x)Comp field campaign held in Julich, Germany in July 2005. Daytime OH levels observed by four instruments were fairly well reproduced to within 33% by a base model run (Regional Atmospheric Chemistry Mechanism with updated isoprene chemistry adapted from Master Chemical Mechanism ver. 3.1) with high R-2 values (0.72-0.97) over a range of isoprene (0.3-2 ppb) and NO (0.1-10 ppb) mixing ratios. Daytime HO2(*) levels, reconstructed from the base model results taking into account the sensitivity …

Molecular Engineered Myoglobin With Unnatural Amino Acids As A Peroxidase, Kananke Sriyani Liyanage

Chemistry & Biochemistry Theses - Archive

Myoglobin (Mb) has been used as a model system to mimic other biologically important heme proteins like cytochrome P450 due to its ability to prepare mixed ligand complexes with different valencies, such as ferric, ferrous and ferryl species. It has been engineered to perform peroxidase, peroxygenase, monooxygenase and catalase activities. However, previous work on this area has shown that the distal histidine (H64) in the active of wild-type Mb is a critical residue, which destabilizes compound I, the reactive intermediate of the catalytic cycle (a ferryl ð-porphyrin radical cation). Therefore in this study we replaced H64 with a smaller residue, …

Bioanalytical Lc-Ms: Streamlined Sampled Preparation And Novel Ambient Ionization Techniques, Samuel Hsiao-Chieh Yang

Chemistry & Biochemistry Dissertations - Archive

Bioanalysis has gained importance in the scientific at an exponential rate. The focus of these works attempt to seek new approaches towards faster and more efficient bioanalysis that require little to no sample preparation. One approach is the use of new restricted access media trap technologies to facilitate an online sample preparation platform. A demonstration of the advantages of RAM involves the trace level detection of bisphenol A, an environmental contaminant. A bulk derivatization strategy used in combination with RAM trap technologies is adopted to boost sensitivity without the use of traditional sample preparation methods. Another strategy is the use …

Pegylated Silicon Nanowire Coated Silica Microparticles For Drug Delivery Across Intestinal Epithelium, Vuk Uskoković, Phin-Peng Lee, Laura Walsh, Kathleen Fischer, Tejal Dasai

Pharmacy Faculty Articles and Research

Composite particles made by growing nanoscopic silicon wires from the surface of monodispersed, microsized silica beads were tested in this study for their ability to affect the integrity and permeability of an epithelial cell layer. Polyethylene glycol (PEG) is known to sterically stabilize particles and prevent protein binding; as such, it is a routine way to impart in vivo longevity to drug carriers. The effect of the silica beads, both with and without silicon nanowires and PEG, on the disruption of the tight junctions in Caco-2 cells was evaluated by means of: (a) analysis of the localization of zonula occludens-1 …

Structure-Reactivity Studies Of Simple 4-Hydroxyprolinamide Organocatalysts In The Asymmetric Michael Addition Reaction Of Aldehydes To Nitroolefins, Fintan Kelleher, John Watts, Lien Luu, Vickie Mckee, Ed Carey

Articles

A series of simple 4-hydroxyprolinamides was synthesised and they were found to act as organocatalysts for the asymmetric conjugate addition of aldehydes to nitroolefins in excellent yields (98%), with complete diastereoselectivity (99:1, syn:anti) and enantioselectivity (98% e.e. for syn). Furthermore, the use of low catalyst loadings (5 mol%) and a low aldehyde molar excess (1.5 equivalents) were achieved.

State Transformations And Ice Nucleation In Glassy Or (Semi-) Solid Amorphous Organic Aerosol, K. J. Baustian, M. E. Wise, E. J. Jensen, G. P. Schill, M. A. Freedman, M. A. Tolbert

CUP Faculty Research

Glassy or amorphous (semi-)solid organic aerosol particles have the potential to serve as surfaces for heterogeneous ice nucleation in cirrus clouds. Raman spectroscopy and optical microscopy have been used in conjunction with a cold stage to examine water uptake and ice nucleation on individual aqueous organic glass particles at atmospherically relevant temperatures (200–273 K). Three organic compounds considered proxies for atmospheric secondary organic aerosol (SOA) were used in this investigation: sucrose, citric acid and glucose. Internally mixed particles consisting of each organic species and ammonium sulfate were also investigated.

Results from water uptake experiments were used to construct glass transition …

Therapeutic Effects Of N-Acetylcysteine Amide In The Treatment Of Eye Disorders, Joshua W. Carey

Doctoral Dissertations

"The loss of vision from age-related eye diseases now affects over 30 million people in the United States and is expected to reach twice that number within the next couple of decades. Among these disorders, age-related macular degeneration and cataract formation represent the largest percentage of these cases. Therapeutic options available for treating age-related macular degeneration are limited and there is no noninvasive form of treatment for cataracts current available. Several studies have indicated that oxidative stress plays an important role in the pathology of these age-related eye disorders. If oxidative stress is responsible for the initiation and progression of …

Caffeine And You, Maxwell Young

Natural Sciences Student Research Presentations

No abstract provided.

From The Lab Into The Kettle, Anthony Mccauley

Natural Sciences Student Research Presentations

No abstract provided.

Provera, Sarah Asklund

Natural Sciences Student Research Presentations

No abstract provided.

Zyrtec, Regan Ford

Natural Sciences Student Research Presentations

No abstract provided.

Ketogenic Diets, Erin Wolfe

Natural Sciences Student Research Presentations

No abstract provided.

Ethanol From The Field To The Pump, Cameron Heiser

Natural Sciences Student Research Presentations

This poster describes the use of dry mill and wet mill processes to produce ethanol.

Mechanochemically Active Polymers, Laura Ward

Natural Sciences Student Research Presentations

No abstract provided.

Polymers Used In Medicine: Common Types And Benefits Of Drug Delivery Systems, Camille Andrews

Natural Sciences Student Research Presentations

This poster describes the common types and benefits of drug delivery systems.

The Many Pharmaceutical Discoveries Of Gertrude B. Elion, Alayna Bonse

Natural Sciences Student Research Presentations

This poster discusses the contributions of Gertrude B. Elion to pharmaceutical science.

Fluoride And Your Teeth: How Fluoride In Dental Products Protects Your Teeth From Cavities, Jacob Dickey

Natural Sciences Student Research Presentations

This poster examines the use and effectiveness of fluorine to prevent cavities.

Understanding Fracture, Allison Marsh

Section 3: Imaging the Fast Moving

No abstract provided.

Wall_1.6 — Acknowledgements, Allison Marsh

Section 1: Introduction

No abstract provided.

Maxwell's Equations, Part V, David W. Ball

Chemistry Faculty Publications

This is the fifth installment in a series devoted to explaining Maxwell’s equations, the four mathematical statements upon which the classical theory of electromagnetic fields – and light – is based. Previous installments can be found on Spectroscopy’s website (whose URL can be found throughout these issues). Maxwell’s equations are expressed in the language of vector calculus, so a significant part of some previous columns have been devoted to explaining vector calculus, not spectroscopy. For better or worse, that’s par for the course, and it’s my job to explain it well – I trust readers will let me know if …

Ƴ-Selective Directed Catalytic Asymmetric Hydroboration Of 1,1-Disubstituted Alkenes, Sean M Smith, Gia L. Hoang, Rhitankar Pal, Mohammad O. Bani Khaled, Liberty S. W. Pelter, Xiao Cheng Zeng, James M. Takacs

Xiao Cheng Zeng Publications

Directed catalytic asymmetric hydroborations of 1,1-disubstituted alkenes afford ƴ

-dioxaborato amides and esters in high enantiomeric purity (90–95% ee).

Dichlorido-1Κcl,3Κcl-Hexakis[1,1,2,2,3,3(Η 5)-Cyclopentadienyl]Di-Μ2- Oxido-1:2Κ 2o:O;2:3Κ 2o:O-Trizirconium(Iv), Bradley M. Kraft, William W. Brennessel

Chemistry Faculty/Staff Publications

No abstract provided.