Chemistry Commons^™

Non-Traditional Examination: A Study To Improve Academic And Research Performance Of Undergraduate Organic Chemistry Students#, Bimal K. Banik, Ram Naresh Yadav, Sunena Chandra

Chemistry Faculty Publications and Presentations

An investigation of conducting a presentation examination instead of a classical written examination method on academic and research performance of undergraduate chemistry students was performed at the University of Texas-Pan American. The results suggest that chemistry students do much better in the presentation examination compared to the written examination at the advanced organic chemistry course. But, the performances of the students in the lower level courses are mixed. However, students do much better in research work when presentation examination was conducted.

Metallosalen-Based Polymers For Reduction Of Carbon Dioxide, Cherawat Kaewyai

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, a series of novel asymmetric copper- and nickel-salens bearing thiophene-based substituents were successfully synthesized and characterized by nuclear magnetic resonance spectroscopy and mass spectrometry. Homogeneous electrocatalytic activities of these monomers toward reduction of CO2 were investigated using cyclic voltammetry technique. Electrochemical studies showed these salen monomers are able to serve as catalysts in the electrochemical reduction of CO2 due to the significantly increase of the current observed under CO2-saturated condition, compared with those found under the N2-saturated one. Results also revealed that insertion of the carbon-carbon triple-bond between the thiophene-based substituents and the salen core led to …

Fast Scan Cyclic Voltammetry For Real-Time Metal Speciation Analysis, Hettige. M. Thushani Siriwardhane

Theses and Dissertations

Electrochemistry is a powerful analytical tool that has been widely used to detect trace metals in natural systems. However, studying the speciation of metals during dynamic events, such as storms and floods, is analytically challenging due to the limited temporal resolution of traditional electrochemical techniques. Additionally, most techniques report the total metal concentration (both complexed and free) that does not reflect the toxicity of these metals, which arise mostly from the free state. To overcome these issues, we previously pioneered the use of fast scan cyclic voltammetry (FSCV) to measure free copper (Cu(II)) and lead (Pb(II)) in real-time in laboratory …

Synthetic Methods For Ester Bond Formation And Conformational Analysis Of Ester-Containing Carbohydrates, Sven Hackbusch

University of the Pacific Theses and Dissertations

This dissertation encompasses work related to synthetic methods for the formation of ester linkages in organic compounds, as well as the investigation of the conformational influence of the ester functional group on the flexibility of inter-saccharide linkages, specifically, and the solution phase structure of ester-containing carbohydrate derivatives, in general.

Stereoselective reactions are an important part of the field of asymmetric synthesis and an understanding of their underlying mechanistic principles is essential for rational method development. Here, the exploration of a diastereoselective O-acylation reaction on a trans-2-substituted cyclohexanol scaffold is presented, along with possible reasons for the observed reversal of stereoselectivity …

Mechanistic Studies Of Nucleic Acid Chaperone Activities Of Retroviral Nucleocapsid Protein, Lichao Sun

Theses and Dissertations

In this dissertation, I have used single molecule Fluorescence Resonance Energy Transfer (sm-FRET), as a nanoscale spectroscopic ruler to gain quantitative, molecular-level understanding about the kinetics and mechanism of NC-chaperoned TAR sequence rearrangements. Firstly, I have resolved the complex kinetics and underlying reaction pathways of TAR sequence annealing in the presence of HIV-1 NC over a broad NC concentration by performing the time-resolved sm-FRET measurements in a unique aggregation-free environment. I have further gained the insights that the NC-induced secondary structural changed of TAR hairpins modulate the annealing pathways and consequently affect the overall kinetics of the TAR sequence annealing. …

Solubility Enhancement Of Model Compounds, Lavanya Pitani

University of the Pacific Theses and Dissertations

Solubility is the amount of solute in the solvent system at phase equilibrium with certain temperature and pressure. Many of the new chemical entities are lipophilic molecules that require techniques to enhance solubility. Solubility enhancement can be achieved by either physical and/or chemical modification of the drug. Various techniques are available for solubility enhancement of poorly soluble drugs include particle size reduction, salt formation, solid dispersions, use of surfactants, prodrug, crystal modification, etc.

In this study, the three model drugs belong to BCS class II and IV having low solubility with a certain range of physicochemical properties were studies in …

Clinical Factors Associated With Hepatitis C Treatment Selection In A Veterans Affairs Population, Carly Anne Ranson

University of the Pacific Theses and Dissertations

Background: Hepatitis C virus is currently the most common chronic blood borne pathogen in the United States, with only half of those infected aware of their condition. The cost for treatment is higher with Harvoni® (ledipasvir/sofosbuvir) than Viekira Pak® (ombitasvir/paritaprevir/ritonavir and dasabuvir). With finite resources available to treat patients, it is important to understand which clinical factors may influence treatment selection decisions.

Methods: The study is a 12-month medical record review within the Veterans Affairs (VA) system to evaluate significant relationships between selected clinical and sociodemographic factors and HCV treatment selection with either Harvoni® or Viekira Pak®. Clinical and demographic …

The Rational Investigation Of Anti-Cancer Peptide Specificity Using The Knob-Socket Model, Shivarni Patel

University of the Pacific Theses and Dissertations

Cancer has been a pervasive and deadly problem for many years. No treatments have been developed that effectively destroy cancer cells while also keeping healthy cells safe. In this work, the knob-socket construct is used to analyze two systems involved in cancer pathways, the PDZ domain and the Bcl-BH3 complex. Application of the knob-socket model in mapping the packing surface topology (PST) allows a direct analysis of the residue groups important for peptide specificity and affinity in both of these systems. PDZ domains are regulatory proteins that bind the C-terminus of peptides involved in the signaling pathway of cancer progression. …

Investigating Secondary Structure Features Of Yap1 Protein Fragments Using Molecular Dynamics (Md) And Steered Molecular Dynamics (Smd) Simulations, Ferdiemar Cardenas Guinto Jr.

University of the Pacific Theses and Dissertations

Molecular dynamics (MD) is a powerful tool that can be applied to protein folding and protein structure. MD allows for the calculation of movement, and final position, of atoms in a biomolecule. These movements can be used to investigate the pathways that allow proteins to fold into energetically favorable structures. While MD is very useful, it still has its limitations. Most notable, computing power and time are of constant concern.

Protein structure is inherently important due to the direct link between the structure of a protein and its function. One of the four levels of protein structure, the secondary structure, …

Synthesis Of Ag10 Analogs And Optimization Of Ttr Ligands For Half-Life Enhancement (Tlhe) Of Peptides, Raghavendra Jampala

University of the Pacific Theses and Dissertations

The misassembly of soluble proteins into toxic aggregates, including amyloid fibrils, underlies a large number of human degenerative diseases. Cardiac amyloidosis, which is most commonly, caused by aggregation of Immunoglobulin (Ig) light chains or transthyretin (TTR) in the cardiac muscle, represent an important and often underdiagnosed cause of heart failure. TTR-mediated amyloid cardiomyopathies are chronic and progressive conditions that lead to arrhythmias, biventricular heart failure, and death. As no Food and Drug Administration-approved drugs are currently available for treatment of these diseases, the development of therapeutic agents that prevent TTR-mediated cardiotoxicity is desired. AG10 is a potent and selective kinetic …

Investigation Of Iron(Ii) Autoxidation Rate And Iron Mediated Geochemical Production Of Reactive Oxygen Species At Oxic-Anoxic Interfaces, Dewamunnage Muditha Chathurangani Dias

Theses and Dissertations

Biogeochemical cycles in ecosystems regulate the flow of energy between reduced species (typically carbon compounds) and a variety of oxidants via both biotic and abiotic reactions. A key class of chemical compounds that can link these cycles through abiotic pathways are Reactive Oxygen Species (ROS). The production of ROS via photochemical pathways is well known. More recently, the non-photochemical production of ROS via the one electron oxidation of ferrous iron (Fe(II)) by dioxygen (O2) has been detected in a range of environments. The oxidation of Fe(II) initiates a pathway that generates an array of ROS as Fe is cycled between …

Chemical Sensing In Harsh Environments By Multivariate Optical Computing, Christopher Michael Jones

Theses and Dissertations

Multivariate optical computing (MOC) is a compressive sensing technique for which an analyte concentration is detected in an interfering mixture by direct detector output. The detector measures the dot product of a linear regression vector with a sample spectrum, as an analog optical computation. The computation is accomplished with the multivariate optical element (MOE), to which the optical regression vector is encoded as a transmission pattern. As a spectrum of light emanates from a sample and passes through the MOE, the dot product naturally occurs when light strikes the detector. The MOC platform allows a simple, robust, and direct measurement …

Metal-Organic Frameworks: A Versatile Platform For Light Harvesting And Energy Transfer, Derek E. Williams

Theses and Dissertations

The global energy demand is undoubtedly rising at an alarming rate, and as a result, humanity faces the problem of finding alternative energy supplies. Approximately 80 percent of the world’s energy currently comes from fossil fuels, and only a small fraction, 10 percent, from renewable energy sources. The study of energy transfer (ET) processes is a rapidly developing area of interest due to the necessity for more efficient photovoltaic devices, which are crucial to meet the growing energy demand. A promising approach to further advance organic photovoltaics is to precisely arrange many lightharvesting chromophores (e.g., porphyrin derivatives), attainable through a …

Redirecting P450 Ferryl-Oxo Intermediates From Oxygenation To Decarboxylation, Job Logan Grant

Theses and Dissertations

A recently discovered cytochrome P450 has garnered much interest for its ability to oxidatively decarboxylate n length fatty acids to n-1 terminal olefins using hydrogen peroxide as an oxidant. This enzyme (P450 OleT) is mechanistically peculiar, as it seemingly abrogates the oxygen insertion chemistry that typifies the P450 superfamily. In this work we explore the origin of this deviant catalysis.

Using stopped-flow and transient kinetic methodologies the ferryl-oxo pi-cation radical and ferryl-hydroxo intermediates, known as compound-I (Cpd-I) and compound-II (Cpd-II) respectively, were isolated in high yield. This is the first time either species has been observed in a substrate bound …

A Miniaturized Spectrophotometric In Situ Ph Sensor For Seawater, Reuben C. Darlington

Graduate Student Theses, Dissertations, & Professional Papers

Since the Industrial Revolution, the world's oceans have absorbed increasing amounts of CO2 and the resultant changes to the marine carbonate chemical system have reduced the pH by > 0.1 units (~ 30%) in surface waters. This acidification of the oceans has many far reaching impacts on marine life and there is great need of quality instrumentation to assess and follow the changing carbonate system. This MIS project aims to develop a low cost pH sensor with high precision and accuracy for open sea measurements with special emphasis on reduced size and cost. Design effort is based on the commercially available …

A Quantum Astrochemical Perspective On The C-C3h Radical With Application To The Interstellar Medium, Matthew Bassett

Electronic Theses and Dissertations

The interstellar medium (ISM) has been an area of focus for astrochemists and quantum chemists for many years, with particular interest in the presence of interstellar molecules and the resulting chemical processes. The c-C3H radical has been detected in the ISM near the dark molecular cloud TMC-1. With the application of ab initio computational methods using coupled-cluster theory at the singles, doubles, and perturbative triples [CCSD(T)] level, highly accurate quartic force fields (QFFs) are constructed to define the electronic wavefunction for the inter nuclear Hamiltonian. The QFF is used to predict the equilibrium geometry and produce vibrational frequencies, rotational constants, …

Synthesis And Biological Activity Of Novel Tu100 Derivatives, Oladotun J. Alao

Electronic Theses and Dissertations

In an attempt to create more effective chemotherapeutic compounds, the naphthoquinone adduct, 12,13-dihydro-N-methyl-6,11,13-trioxo-5H-benzo[4,5]cyclohepta [1,2 b]naphthalen-5,12-imine (hereafter called TU100) was synthesized. Inspired by its unique and novel mechanism of action, a series of structural derivatives were synthesized to explore structure-activity relationships. The analogues exhibited different cytotoxicity profiles, revealing the indicated regions are involved in cell death induction. Furthermore, the analogues had dramatically different effects on cellular ATP production, suggesting different molecular targets. Synthesis, biological activity, and SAR study of these analogues will be revealed.

Asymmetric Membranes For High Capacity Lithium-Ion Battery Electrodes, Ian Byrd

Electronic Theses and Dissertations

Lithium-Ion Batteries (LIBs) have broad applications such as portable electronic devices, electric vehicles, and for green energy storage from intermittent sources. Current LIBs are limited by their low capacity materials at both the anode and cathode. At the anode, graphite suffers from a low capacity of only 372 mAh g^-1. The most commonly used cathode material is LiCoO₂ which has a meager capacity of 140 mAh g^-1. Thereby the broader applications of LIBs are limited due to these low capacities. It is imperative to develop higher capacity materials to further improve the performance of LIBs. …

Approaches Toward Novel 1,2,3-Triazole Sensors For The Detection Of Anions And Heavy Metal Cations, Richard D. Govan

Electronic Theses and Dissertations

Cations and anions play pivotal roles in biological and physiological processes, however an imbalance in concentration of any ion can be detrimental. Therefore, research into the selective recognition of anions and heavy metal cations has acquired much attention. One approach involves the use of chemosensors. Upon interaction with targeted analytes, chemosensors produce a distinct response, in some cases a fluorescent or colorimetric signal. The 1,2,3-triazole unit has much potential as a chemical sensor due to its unique photophysical properties. The specificity, selectivity, and signaling mechanism of triazole sensors can be tuned with conjugation in the motif and choice and placement …

Α-Eleostearic Acid Extraction By Saponification Of Tung Oil And Its Subsequent Polymerization, Amanda Murawski

Electronic Theses and Dissertations

The goal of environmentally sound research is to provide alternatives that are more sustainable and renewable, such as vegetable oil-based polymers, than the current petroleum-based products. Vegetable oil-based polymers have received a lot of attention recently due their multifaceted properties, which are simply achieved by adjusting the monomer or resin composition. The carbon-carbon double bonds in unsaturated oils are ideal reactive sites for the free radical or cationic polymerizations. Most vegetable oils must be modified before polymerization due to the low reactivity of their non-conjugated fatty acid chains. Tung oil (TO) contains ~83% of a triply conjugated fatty acid ( …