Digital Commons Network^™

Thioenamide Synthesis Inspired By Peptide Macrocycles, Joshua Allen Lutz

LSU Doctoral Dissertations

Despite advances in medicine, antibiotic resistance threatens to return once preventable diseases to the human population. The microbisporicins are 24-amino acid antibiotic peptides belonging to the lantibiotic class, which pathogens have been slow to develop resistance. The uncommon post-translational modification S-[(Z)-2-aminovinyl]-D-cysteine (AviCys) is likely crucial to their activity, and appears in a small number of other peptides with compelling biological activities. Total synthesis of an AviCys-containing peptide has eluded the chemical community.

The primary challenge of AviCys synthesis is the construction of a thioenamide functional group. We demonstrate that acid-promoted reactions between an amide and …

Development Of A Tunable Platform For The Study Of Geomacromolecular Matrices Using Controlled Radical Polymerization, Arjun Pandey

LSU Doctoral Dissertations

Soil is an important environmental component, and the study of soil processes have many practical implications such as improvement in agriculture, mitigation of climate change etc. The widespread use of Agricultural Chemicals (ACs) in modern agriculture has resulted in adverse effects in environment and human health mostly through contamination into food and water sources. Study of fate, bioavailability, and transport of ACs involves molecular level understanding of their interactions with soil. This can be challenging due to complex and heterogeneous nature of soil. One common approach used is the correlation of macroscopic properties of soil, (e.g. sorption) with empirical parameters …

Determination Of Cannabinoids, Cathinones, And Synthetic Fentanyls Using Wastewater-Based Epidemiology, Catherine O'Rourke, Bikram Subedi

Posters-at-the-Capitol

Unregulated new psychoactive substances (NPS) in “pure” or “preparation” forms are designed to mimic the effects of controlled substances, and are introduced and reintroduced in the market as a cheap substitute for established regulated drugs in quick succession to loophole the law enforcement efforts on combating drugs. For example, carfentanil, a synthetic opioid activates the opioid receptors similar to morphine but it is astoundingly potent compared to a typical drug of abuse (100 times more potent than fentanyl and 10,000 times more powerful than morphine). Based on the cost- and time-intensive forensic analysis, National Drug Early Warning System reported the …

Stacked Core-Shell & Self-Supported Nanorod Array Electrocatalysts For Pem Fuel Cells, Fatma Merve Yurtsever

Theses and Dissertations

Polymer electrolyte membrane fuel cell (PEMFC) is one of the most attractive technologies for clean, renewable energy in the twenty-first century. It has many advantages in terms of zero carbon emission, quiet operation mode, high power density, higher efficiency than Carnot engines, and it requires less warm-up & fast start-up time. However, oxygen reduction reaction (ORR) activity and stability are still significant issues for the next generation PEMFCs to increase its usage. In this study, we developed a new design of stacked core-shell nanorod array and self-supported composition graded Pt:Ni nanorod array electrocatalyst to improve ORR kinetics and catalyst stability. …

Samarium-Activated La2hf2o7 Nanoparticles As Multifunctional Phosphors, Santosh K. Gupta, Maya Abdou, Jose P. Zuniga, Alexander A. Puretzky, Yuanbing Mao

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

Recent developments in the field of designing novel nanostructures with various functionalities have pushed the scientific world to design and develop high-quality nanomaterials with multifunctional applications. Here, we propose a new kind of doped metal oxide pyrochlore nanostructure for solid-state phosphor, X-ray scintillator, and optical thermometry. The developed samarium-activated La2Hf2O7 (LHOS) nanoparticles (NPs) emit a narrow and stable red emission with lower color temperature and adequate critical distance under near-UV and X-ray excitations. When the LHOS NPs are exposed to an energetic X-ray beam, the Sm3+ ions situated at the symmetric environment get excited along with those located at the …

Ultrafast And Real-Time Dynamics Of Nanomaterials Studied By Advanced Spectroscopic Techniques, Jeewan Chaminda Ranasinghe

LSU Doctoral Dissertations

Ultrafast and nonlinear spectroscopies are used to study excited-state dynamics and monitor real-time growth dynamics of different types of nanomaterials. In the first study, the growth dynamics of colloidal gold-silver core-shell nanoparticles are studied using in situ second harmonic generation and extinction spectroscopy. The growth lifetimes are studied under different reaction conditions, resulting in different silver shell thicknesses, with spectral comparisons to finite-difference time-domain calculations. The results are consistent with a three-step growth process. During the first step of the nanoparticle growth reaction, rough and uneven surfaces are formed rapidly giving rise to plasmonic hot spots with corresponding broad, red-shifted …

Silica And Siloxane Model Systems, Bruno Jakobi

LSU Doctoral Dissertations

This dissertation focuses on the development and synthesis of model system for the investigation of the morphology, interactions, and dynamics in linear and branched polymers and polymer nanocomposites. The materials are designed to reduce the number of uncontrolled parameters and to be ideally suitable for neutron scattering studies. Hereby, two main objectives are defined:

The first project is to develop model nanocomposites based on the grafting of poly(dimethylsiloxane) (PDMS) to primary particles and well-defined aggregates. For that purpose, the functionalization of silica nanoparticles with a chlorosilane and the influence of moisture on the reaction was studied. Higher grafting densities than …

Intrinsic Cleavage Inhibition By Thermophilic Type Ii-S Restriction Endonucleases, Dino Jake Ciccone

Master of Science in Chemical Sciences Theses

Restriction endonucleases (REs) are the cornerstone research tools used in molecular biology and biotechnology. These enzymes are essential to several ground-breaking achievements, including DNA cloning, gene editing, and genome mapping. A subset of these enzymes, Type II-S restriction endonucleases (IISREs), cleave double-stranded DNA (dsDNA) not governed by sequence specificity, but rather at a fixed distance from their recognition sequence. These enzymes maintain complete cleavage promiscuity, allowing utilization in techniques such as Golden Gate assembly, Serial Analysis of Gene Expression (SAGE), and Restriction Endonuclease Protection, Selection, and Amplification (REPSA). However, laboratories generated evidence that intrinsically cleavage refractory sequences exist. Understanding the …

Medium-Dependent Antibacterial Properties And Bacterial Filtration Ability Of Reduced Graphene Oxide, Alexander Gusev, Olga Zakharova, Dmitry S. Muratov, Nataliia S. Vorobeva, Mamun Sarker, Iaroslav Rybkin, Daniil Bratashov, Evgeny Kolesnikov, Aleš Lapanje, Denis V. Kuznetsov, Alexander Sinitskii

Department of Chemistry: Faculty Publications

Toxicity of reduced graphene oxide (rGO) has been a topic of multiple studies and was shown to depend on a variety of characteristics of rGO and biological objects of interest. In this paper, we demonstrate that when studying the same dispersions of rGO and fluorescent Escherichia coli (E. coli) bacteria, the outcome of nanotoxicity experiments also depends on the type of culture medium. We show that rGO inhibits the growth of bacteria in a nutrition medium but shows little eect on the behavior of E. coli in a physiological saline solution. The observed eects of rGO on E. coli in …

Turn-On Near-Infrared Fluorescent Sensors For Selective Monitoring Of Kinase Activity, Gerard Thomas Ducharme

LSU Doctoral Dissertations

Reliable and selective detection of specific biopolymers is critical in a broad range of biomedical and technological areas, including availability of simple and efficient point-of-care-compatible systems for the detection of prognostic, pharmacodynamic and predictive biomarkers. Monitoring epidermal growth factor receptor (EGFR) tyrosine kinase is of major significance due to its link to many epithelial cancers. This task is complicated by the high rate of mutation occurring in patients treated with kinase inhibitors. This dissertation describes a conceptually novel design and synthesis of turn-on near-infrared fluorescent sensors for selective and sensitive detection of EGFR. The fluorescent signal generation mechanism is based …

Syntheses, Characterization, And Preliminary Evaluation Of Potential Ruthenium Anticancer Complexes Containing Schiff Base Ligands, Stephen Mensah

Theses and Dissertations

Platinum-based drugs have over the years been administered in the treatment of tumours.

Unfortunately, platinum resistance and the severe side effects associated with the treatments has necessitated the research for new anti-cancer drugs. Ruthenium(II) and Ruthenium(III) complexes have shown promise as useful alternative anticancer agents. The lead candidates include the Ru(II) complex RAPTA-C, a ruthenium(II)-arene complex [Ru(η6-p-cymene)Cl2(1,3,5-triaza-7-phosphaadamantane)] and the Ru(III) complex NAMI-A [imidazoleH][trans-Ru(imidazole) (dimethyl sulfoxide)Cl4]. Both compounds have shown potent cytotoxic activity in several primary human tumor models. Unfortunately, NAMI-A could not advance in clinical evaluations due to limited efficacy in vivo, while the clinical evaluation of RAPTA-C is unknown. …

Co-Localization Of Dna I-Motif-Forming Sequences And 5-Hydroxymethyl-Cytosines In Human Embryonic Stem Cells, Yogini P. Bhavsar-Jog, Eric Van Dornshuld, Tracy A. Brooks, Gregory S. Tschumper, Randy M. Wadkins

Faculty and Student Publications

G-quadruplexes (G4s) and i-motifs (iMs) are tetraplex DNA structures. Sequences capable of forming G4/iMs are abundant near the transcription start sites (TSS) of several genes. G4/iMs affect gene expression in vitro. Depending on the gene, the presence of G4/iMs can enhance or suppress expression, making it challenging to discern the underlying mechanism by which they operate. Factors affecting G4/iM structures can provide additional insight into their mechanism of regulation. One such factor is epigenetic modification. The 5-hydroxymethylated cytosines (5hmCs) are epigenetic modifications that occur abundantly in human embryonic stem cells (hESC). The 5hmCs, like G4/iMs, are known to participate in …

Co-Localization Of Dna I-Motif-Forming Sequences And 5-Hydroxymethyl-Cytosines In Human Embryonic Stem Cells, Yogini P. Bhavsar-Jog, Eric Van Dornshuld, Tracy A. Brooks, Gregory S. Tschumper, Randy M. Wadkins

Chemistry Faculty Research & Creative Works

G-quadruplexes (G4s) and i-motifs (iMs) are tetraplex DNA structures. Sequences capable of forming G4/iMs are abundant near the transcription start sites (TSS) of several genes. G4/iMs affect gene expression in vitro. Depending on the gene, the presence of G4/iMs can enhance or suppress expression, making it challenging to discern the underlying mechanism by which they operate. Factors affecting G4/iM structures can provide additional insight into their mechanism of regulation. One such factor is epigenetic modification. The 5-hydroxymethylated cytosines (5hmCs) are epigenetic modifications that occur abundantly in human embryonic stem cells (hESC). The 5hmCs, like G4/iMs, are known to participate in …

Computationally Aided Design Of A High-Performance Organic Semiconductor: The Development Of A Universal Crystal Engineering Core, Anthony J. Petty Ii, Qianxiang Ai, Jeni C. Sorli, Hamna F. Haneef, Geoffrey E. Purdum, Alex M. Boehm, Devin B. Granger, Kaichen Gu, Carla Patricia Lacerda Rubinger, Sean R. Parkin, Kenneth R. Graham, Oana D. Jurchescu, Yueh-Lin Loo, Chad Risko, John E. Anthony

Chemistry Faculty Publications

Herein, we describe the design and synthesis of a suite of molecules based on a benzodithiophene “universal crystal engineering core”. After computationally screening derivatives, a trialkylsilylethyne-based crystal engineering strategy was employed to tailor the crystal packing for use as the active material in an organic field-effect transistor. Electronic structure calculations were undertaken to reveal derivatives that exhibit exceptional potential for high-efficiency hole transport. The promising theoretical properties are reflected in the preliminary device results, with the computationally optimized material showing simple solution processing, enhanced stability, and a maximum hole mobility of 1.6 cm² V⁻¹ s⁻¹.

Nextgen Advises "Trying To Manage", Douglass Steinhauff, Joel Henrique Ellwanger, Monika Lewinska, Edmond Sanganyado, Yongsheng Ji, Buddini Iroshika Karawdeniya, Naike Bochatay, Eric Britt Moore, Aminata Coulibaly, Shaima Ibrahim, Déna Skye Jansen, Joshua I. James, David M. Cole, Anna Lipkin, Beth Mckinnon Adamowicz, Science Management Associates, Shervin Fatehi, Maria Helena Holmstrom, Rosa Li

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

Peer mentors can provide crucial support to young scientists by asking questions to facilitate further reflection, assuring mentees that they are not alone, and suggesting potential next steps. We asked our readers to act as peer mentors to “Trying to Manage,” the anonymous student who posed the question above. Follow NextGen Voices on Twitter with hashtag #NextGenSci. Read previous NextGen Voices survey results at https://science.sciencemag.org/collection/nextgen-voices. —Jennifer Sills

Synthesis Of Ether Alcohols With Varying Catalysts, Hannah Grady, Frida Li, Jeffrey A. Hansen

Annual Student Research Poster Session

It has previously been found that acids and bases are effective catalysts in the opening of epoxides into ether alcohols. Our first goal for this summer was to determine which of the acids and bases available were the most effective. After figuring out which of the acids and bases are the optimal catalysts, our second goal was producing ether alcohols in the shortest amount of time with higher yields. Our final goal was to see how biologically reactive the ether alcohols we produced were.

Opening Of An Epoxide Ring Using Azide To Form A Triazole, Emily Hufnagel, Jeffrey A. Hansen

Annual Student Research Poster Session

The purpose of this research project is to identify and synthesize biologically active compounds that could potentially aid in pharmaceutical research. Once a compound is correctly identified and purified, the sample can be diluted and added to a Brine Shrimp Lethality Assay in order to determine the toxicity of the compound. This experiment was designed using an epoxide compound to form an azide that would eventually form a triazole. In carrying out this project, two main procedures were used in order to create two different compounds that would eventually create the final result. The triazole was not successful in the …

Increasing Expression Of Civic-Engagement Values By Students In A Service-Learning Chemistry Course, Audrey E. Mcgowin, Rebecca Teed

Chemistry Faculty Publications

A service-learning course at a midsized Midwestern research university was modified over a period of six years to integrate best-practice pedagogies that have been shown to increase civic engagement by students. Best-practice pedagogies included regular interaction with community partner(s), significant time spent on the service activity, and regular reflection (written and verbal) on the implications of the service activity. Besides water quality monitoring, students performed private well water analysis, wrote multiple formal reflection papers, and presented a public talk on the results of their project that included significant discussion time with community partners. Authentic expression of civic engagement values was …

Antioxidants And Beta-Carotene: A General Overview, A Research History, And Modern Scholarship, James Joseph Dickman Iv

Chemistry & Biochemistry Student Projects

This paper seeks to provide a cursory overview of oxidative stress and the accompanying biomolecules which are used to combat it. From there, the paper will provide a somewhat comprehensive list of major historical discoveries regarding antioxidant molecules, in particular beta-carotene. After this, an overview of more modern scholarship on the issue of these molecule’s antioxidant properties specific (from the 1970s onward) will be discussed up to modern times. The paper will conclude with an in depth look at the modern scholarship on beta-carotene that was performed here at Taylor University.

Bone Regeneration Via Inorganic/Organic Compatibility In A Newly Synthesized Hydrogel: Nhap-Bmp-2, Hannah Ewing

Chemistry & Biochemistry Student Projects

In this paper, nHAp-BMP-2 hydrogel is carefully synthesized in order to optimize the organic and inorganic compatibility which induces osteogenesis—the formation of new bone. This new method is a novel development within the medical field, giving more hope to those suffering from traumatic bone injuries. A drawback with using hydrogels is the difficulty of controlling peptide release in the affected areas. Too quick of a release alarms the human inflammatory response resulting in more substantial injury and an even prolonged recovery time. On the other hand, if the peptides that promote bioactivity are released too slowly, the bone will not …

Metallodrugs And Their Various Impacts On Disorders And Diseases, Paige Wagner

Chemistry & Biochemistry Student Projects

No abstract provided.

Can The Merpas Passive Air Sampler Discriminate Landscape, Seasonal, And Elevation Effects On Atmospheric Mercury? A Feasibility Study In Mississippi, Usa, Byunggwon Jeon, James V. Cizdziel

Faculty and Student Publications

© 2019 by the authors. Accurately measuring gaseous elemental mercury (GEM) concentrations in the atmosphere is important to understand its sources, cycling, distribution, and temporal trends. The MerPAS passive air sampler from Tekran Inc. (Toronto, ON, Canada) captures GEM on sulfur-impregnated activated carbon after it passes through a Radeillo diffusive barrier. Because they are small, relatively low in cost, and require no power, they can be deployed at multiple locations, yielding a much greater spatial resolution, albeit at coarser temporal resolution, compared to active sampling. In this study, we used the MerPAS to measure GEM concentration gradients at a mixed …

The Periodical Fall 2019, Southern Adventist University

the Periodical – Chemistry Department Newsletter

Volume 7, issue 1 of the Periodical includes articles about new faculty member Tamie Suzuki, an alumni spotlight, general department news, at a pictorial listing of 2019 December chemistry graduates.

Leaving Ligand Effects On Reactivity And Solubility Of Monofunctional Platinum(Ii) Anticancer Complexes, Heidi Linn Hruska Millay

Masters Theses & Specialist Projects

Monofunctional platinum(II) complexes, such as phenanthriplatin and pyriplatin, have notably different characteristics from the bifunctional anticancer complexes, such as cisplatin and oxaliplatin, which have detrimental toxicities and resistance associated with them. The unique properties of the monofunctional complexes may be exploited to target cancer cells without producing the toxic side effects associated with the current FDA-approved platinum-based anticancer drugs. To advance the understanding of these monofunctional platinum(II) complexes, this study replaced the chloride leaving ligand with an acetate group, which should increase solubility and alter the rate of reactivity with key amino acid and nucleotide targets. Phenanthriplatin and pyriplatin compounds …

Interaction Of A Platinum Triamine Complex Having A Seven-Membered Chelate Ring With N-Acetyl-Lmethionine And Guanosine 5'-Monophosphate, Jae Ko

Masters Theses & Specialist Projects

In the 1960s, Rosenberg and his colleagues confirmed the anti-cancer activity of cisplatin. Although cisplatin was capable of killing testicular cancer cells there were also serious side effects. It was necessary to find alternate ways of overcoming side effects, and soon many researchers have discovered novel platinum compounds that show similar reactivity. Recently, replacing one chloride group to a heterocyclic amine group showed significant cytotoxicity with a different binding activity than cisplatin. Previously in our lab, [Pt(Me5dien)(NO3)]+ and [Pt(Et2dien)Cl]+ have been synthesized and reacted with NAcetyl- L-methionine (N-AcMet) and Guanosine 5’-monophosphate (5’-GMP) showed unusual reactivity. Unlike most previously studied platinum …

Chemical Speciation In Silver Bow And Blacktail Creeks: Implications For Bioavailability And Restoration, Johnathan Feldman

Graduate Theses & Non-Theses

Silver Bow and Blacktail Creeks, contaminated with toxic elements from mining, present a need for remediation and restoration. Trace elements are present in elevated concentrations, particularly copper. Determining element speciation will allow informed consideration of effective restoration strategies, by providing a foundation for assessing bioavailability and toxicity. The three goals are: determine how speciation varies between seasons and sites in four impacted sites from the greater Butte Area One, an impacted downstream site known as Santa, and a control site on Upper Blacktail Creek known as Blacktail; how these variations influence bioavailability and toxicity; and what causes these variations. Total …

Synthesis Of Bis(Imino)Pyridine Iron(Ii) Complexes And Development Of Bis(Imino)Pyridine Iron(Ii) Catalyzed Carbene Transfer Reactions, Ban Wang

Masters Theses & Specialist Projects

Metal catalysis of symmetric and asymmetric carbene transfer reactions has been widely applied in natural product synthesis and material science over years. Metal carbene can be easily generated from the extrusion of nitrogen under the catalysis of metal complexes to further undergo various organic reactions, O/N/C-H insertions, cycloadditions, and ylide formations. Currently, the dominant effective catalysts for carbene reactions are built with expensive precious metal, for example, rhodium, ruthenium, palladium, gold. Notably, the effective reactivity and enantioselectivity of the dirhodium(II) catalysts are researched and established over the decades. However, the use of precious metal catalysts is the major source of …

Double-Click Enables Synthesis Of Chemical Libraries For Drug Discovery, Joseph J. Topczewski, En Chih Liu

Chemistry Faculty Research & Creative Works

No abstract provided.

Electrochemistry Of Illusive Barbosalite, Fe²⁺Fe³⁺ 2(Po₄)₂(Oh)₂: An Iron Phosphate Related To Lipscombite Structure, Prashanth Sandineni, Kartik Ghosh, Amitava Choudhury

Chemistry Faculty Research & Creative Works

Barbosalite, an iron hydroxy-phosphate belonging to the family of Lazulite has been synthesized using hydrothermal route and its electrochemical property is investigated for the first time with respect to Li-ion batteries. The structure, as determined from single-crystal X-ray diffraction data, built up of undulating layers of FeO₆ octahedra, consisting of trimers and PO₄ tetrahedral units. Magnetic susceptibility measurements show predominant overall anti-ferromagnetic interactions and room temperature 57Fe Mössbauer spectroscopic studies confirm the mixed 3+ and 2+ oxidation states of Fe in the compound. The compound is stable up to 400°C and undergo facile electrochemical lithium insertion. Galvanostatic charge-discharge …

Organic Chemistry Ii Lab Manual, Caitlyn Bailey

Senior Honors Theses

This project aims to supply a full lab manual and grading key for Organic Chemistry II, a class often taken by sophomores in Liberty University’s science degree programs. Properly applied laboratory experiments create a beneficial learning environment for science students by using hands-on procedures to transform intangible lecture concepts into concrete demonstrations. Lab work also fosters the development of problem-solving and critical-thinking skills that students need in research and the workplace. Thus, having a comprehensive lab manual is critical to students’ success and understanding in this upper-level class. This project adds to the experiments of Organic Chemistry II lab through …