Chemistry Commons^™

Chalcogen Bonding Of Two Ligands To Hypervalent Yf4 (Y=S, Se, Te, Po), Wiktor Zierkiewicz, Rafal Wysokiński, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The ability of two NH3 ligands to engage in simultaneous chalcogen bonds to a hypervalent YF4 molecule, with Y=S, Se, Te, Po, is assessed via quantum calculations. The complex can take on one of two different geometries. The cis structure places the two ligands adjacent to one another ina pseudo-octahedral geometry, held there by a pair of σ-hole chalcogen bonds. The bases can also lie nearly opposite one another, in a distorted octahedron containing one π-hole and one strained σ-hole bond. The cis geometry is favored for Y=S, while Te,and Po tend toward the trans structure; they are nearly equally …

Production Of Singlet Oxygen (1O2) During The Photochemistry Of Aqueous Pyruvic Acid: The Effects Of Ph And Photon Flux Under Steady-State O2(Aq) Concentration, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The photochemistry of pyruvic acid (PA) in aqueous atmospheric particles contributes to the production of secondary organic aerosols. This work investigates the fate of ketyl and acetyl radicals produced during the photolysis (λ ≥ 305 nm) of 5-100 mM PA under steady state [O₂(aq)] = 260 μM (1.0 ≤ pH ≤ 4.5) for photon fluxes between 1 and 10 suns. The radicals diffuse quickly into the water/air interface of microbubbles and react with dissolved O₂ to produce singlet oxygen (¹O₂^*). Furfuryl alcohol is used to trap and bracket the steady-state production of …

Sequence-Defined Ionic Peptoid Block Copolymers: Synthesis And Solution Self-Assembly, Garrett Leigh Sternhagen

LSU Doctoral Dissertations

This work covers efforts to develop a peptoid-based model system for systematically studying the role of ionic functional groups in determining the structure of ionic block copolymer (BCP) self-assemblies in water. A key challenge in the study of polyelectrolytes is the lack of synthetic control over the location of ionic monomers along a polymer chain. We developed a model system based on sequence-defined ionic peptoid BCPs having discrete chain length and precisely positioned ionic monomers along the chain to specifically address this issue. In Chapter 1, synthetic strategies to access well-defined polypeptoids and their application in BCP synthesis are reviewed. …

Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang

Faculty Publications

Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are among the most prevailing methods for block copolymer self-assembly. Taking the merits of scalability of PISA and dimension control of CDSA, we report one-pot synchronous PISA and CDSA ring-opening metathesis polymerization (ROMP) to prepare nano-objects based on a crystalline poly(ruthenocene) motif. We denote this self-assembly methodology as ROMPI-CDSA to enable a simple, yet robust approach for the preparation of functional nanomaterials.

Nitric Oxide Is Involved In Heavy Ion-Induced Non-Targeted Effects In Human Fibroblasts, Megumi Hada, Premkumar B. Saganti, Francis A. Cucinotta

Health Physics and Diagnostic Sciences Faculty Research

Previously, we investigated the dose response for chromosomal aberration (CA) for exposures corresponding to less than one particle traversal per cell nucleus by high energy and charge (HZE) particles, and showed that the dose responses for simple exchanges for human fibroblast irradiated under confluent culture conditions were best fit by non-linear models motivated by a non-targeted effect (NTE). Our results suggested that the simple exchanges in normal human fibroblasts have an important NTE contribution at low particle fluence. Nitric oxide (NO) has been reported as a candidate for intercellular signaling for NTE in many studies. In order to estimate the …

The Effects Of Citric Acid On Ph And Nutrient Uptake In Wheatgrass (Triticum Aestivum), Cristina Tusei

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

No abstract provided.

Preface To Special Issue “International Year Of The Periodic Table: From Mendeleev To Cluster Chemistry”, Richard D. Adams, Boon Teo, Vladimir P. Fedin

Faculty Publications

No abstract provided.

Beam Loss Analysis Through Particle Tracking Simulation, Marvin Valverde

STAR Program Research Presentations

Water soluble-polymers are commonly used to build detergents or other types of surfactants. These polymers are important because water soluble-polymers used in the development of surfactants have become an essential new factor in the cleaning of oil. However, the development of these surfactants has been constrained by the difficulty of producing them. For this synthesis, phenolic maleimide was used as starting material for a water-soluble polymer. This polymer will be able to break apart at set temperatures and self-assemble into a surfactant.

Air/Surface Exchange Of Gaseous Elemental Mercury At Different Landscapes In Mississippi, Usa, James V. Cizdziel, Yi Zhang, Divya Nallamothu, J. Stephen Brewer, Zhiqiang Gao

Faculty and Student Publications

© 2019 by the authors. Mercury (Hg) is a global pollutant with human health and ecological impacts. Gas exchange between terrestrial surfaces and the atmosphere is an important route for Hg to enter and exit ecosystems. Here, we used a dynamic flux chamber to measure gaseous elemental Hg (GEM) exchange over different landscapes in Mississippi, including in situ measurements for a wetland (soil and water), forest floor, pond, mowed field and grass-covered lawn, as well as mesocosm experiments for three different agricultural soils. Fluxes were measured during both the summer and winter. Mean ambient levels of GEM ranged between 0.93-1.57 …

Computational Insights Into Mg-Cl Complex Electrolytes For Rechargeable Magnesium Batteries, Jared B. Moss, Liping Zhang, Kevin V. Nielson, Yujing Bi, Chao Wu, Steve Scheiner, Tianbiao Leo Liu

Chemistry and Biochemistry Faculty Publications

DFT calculations were conducted to provide insightful and unprecedented thermodynamic insights on tetrahydrofuran (THF) solvation, isomerization, chlorination, and complexation of possible Mg-Cl coordination species for the popular Mg-Cl electrolytes. Computational results using the M06-2x functional with the 6-31+G(d) basis set indicate trigonal bipyramidal e, e-cis-tbp-MgCl2(THF)3 dichloride species and octahedral [MgCl(THF)5]+ monochloride species are the dominant mononuclear species. These two can combine to form the active dinuclear species, [(μ-Cl)3Mg2(THF)6]+ with a free energy -6.30 kcal/mol, which is calculated to be the dominant Mg-Cl species in solution. Two mono-cation species, [(μ-Cl)3Mg2(THF)6]+ and [MgCl(THF)5]+ have comparable LUMO energies, thus both of them can …

Understanding Interactions Of Citropin 1.1 Analogues With Model Membranes And Their Influence On Biological Activity, Nathalia Rodrigues De Almeida, Jonathan Catazaro, Maddeboina Krishnaiah, Yashpal Singh Chhonker, Daryl J. Murry, Robert Powers, Martin Conda-Sheridan

Department of Chemistry: Faculty Publications

The rapid emergence of resistant bacterial strains has made the search for new antibacterial agents an endeavor of paramount importance. Cationic antimicrobial peptides (AMPs) have the ability to kill resistant pathogens while diminishing the development of resistance. Citropin 1.1 (Cit 1.1) is an AMP effective against a broad range of pathogens. 20 analogues of Cit 1.1 were prepared to understand how sequence variations lead to changes in structure and biological activity. Various analogues exhibited an increased antimicrobial activity relative to Cit 1.1. The two most promising, AMP-016 (W3F) and AMP-017 (W3F, D4R, K7R) presented a 2- to 8-fold increase in …

Printing 3d Models For Chemistry: A Step-By-Step Open-Source Guide For Hobbyists, Corporate Professionals, And Educators And Students In K-12 And Higher Education, Elisabeth Grace Billman-Benveniste, Jacob Franz, Loredana Valenzano-Slough

Open Access Books

3D-printing is a relatively inexpensive additive manufacturing method used to create tangible objects. As a relatively new technology, the true capability of 3D-printing has not yet been fully exploited, especially in academic and research/teaching settings. Through this work, 3D-printing in a classroom and research environment is employed as a tool for creation of fully customizable, three-dimensional molecular models and for the visualization of theoretical abstract concepts.

Fisetin, A 3,7,3 ',4 '-Tetrahydroxyflavone Inhibits The Pi3k/Akt/Mtor And Mapk Pathways And Ameliorates Psoriasis Pathology In 2d And 3d Organotypic Human Inflammatory Skin Models, Konstantin G. Kousoulas

Faculty Publications

Psoriasis is a chronic immune-mediated skin disease that involves the interaction of immune and skin cells, and is characterized by cytokine-driven epidermal hyperplasia, deviant differentiation, inflammation, and angiogenesis. Because the available treatments for psoriasis have significant limitations, dietary products are potential natural sources of therapeutic molecules, which can repair the molecular defects associated with psoriasis and could possibly be developed for its management. Fisetin (3,7,3 ',4 '-tetrahydroxyflavone), a phytochemical naturally found in pigmented fruits and vegetables, has demonstrated proapoptotic and antioxidant effects in several malignancies. This study utilized biochemical, cellular, pharmacological, and tissue engineering tools to characterize the effects of …

Steroidal Alkaloid Variation In Veratrum Californicum As Determined By Modern Methods Of Analytical Analysis, Matthew W. Turner, Meagan Rossi, Vannessa Campfield, John French, Ellie Hunt, Emily Wade, Owen M. Mcdougal

Chemistry and Biochemistry Faculty Publications and Presentations

Veratrum californicum is a rich source of steroidal alkaloids, many of which have proven to be antagonists of the Hedgehog (Hh) signaling pathway that becomes aberrant in over twenty types of cancer. These alkaloids first became known in the 1950's due to their teratogenic properties, which resulted in newborn and fetal lambs developing cyclopia as a result of pregnant ewes consuming Veratrum californicum. It was discovered that the alkaloids in V. californicum were concentrated in the root and rhizome of the plant with much lower amounts of the most active alkaloid, cyclopamine, present in the aerial plant, especially in …

Google Funds Cold Fusion Research; Results Still Negative, David W. Ball

Chemistry Faculty Publications

No abstract provided.

Electrochemical Carbon Nanoprobes For Biological And Chemical System Studies, Keke Hu

Dissertations, Theses, and Capstone Projects

The progress in the field of nanoelectrochemistry requires preparation and characterization of nanometer scale electrochemical probes. The focus of my Ph.D. research was on development of carbon nanopipette-based electrodes with versatile and controllable geometry and their applications to nanoscale studies of chemical and biological systems. Carbon nanopipette (CNP) electrodes offer important advantages, including high sensitivity and improved analytical selectivity. They can serve as nanoreactors for sampling ultra-small solution volumes and studies of individual nanoparticles. CNPs were prepared by chemical vapor deposition (CVD) of carbon into the pre-pulled quartz capillaries. By changing pulling parameters and CVD conditions, we fabricated several types …

Evaluation Of Α-Hydroxycinnamic Acids As Pyruvate Carboxylase Inhibitors, Daniel J. Burkett, Brittney N. Wyatt, Mallory Mews, Anson Bautista, Ryan Engel, Chris Dockendorff, William A. Donaldson, Martin St. Maurice

Chemistry Faculty Research and Publications

Through a structure-based drug design project (SBDD), potent small molecule inhibitors of pyruvate carboxylase (PC) have been discovered. A series of α-keto acids (7) and α-hydroxycinnamic acids (8) were prepared and evaluated for inhibition of PC in two assays. The two most potent inhibitors were 3,3′-(1,4-phenylene)bis[2-hydroxy-2-propenoic acid] (8u) and 2-hydroxy-3-(quinoline-2-yl)propenoic acid (8v) with IC₅₀ values of 3.0 ± 1.0 μM and 4.3 ± 1.5 μM respectively. Compound 8v is a competitive inhibitor with respect to pyruvate (K_i = 0.74 μM) and a mixed-type inhibitor with respect to ATP, indicating …

Probing The Gelation Phenomena In Molecular And Seed-Based Gels, Malick Samateh

Dissertations, Theses, and Capstone Projects

The interest in molecular gels has been gaining momentum as evident from being developed for a broad spectrum of applications. This impetus stems from several reasons that include: (i) molecular gels are highly stimuli responsive as they easily respond to thermodynamic changes, disintegrating into well-defined chemicals/building blocks because of the purely physical (in contrast to chemically cross-linked) nature of the interactions holding their 3D networks together; (ii) the sheer abundance of simple small molecules to choose starting materials from and the vast potential of tunability of the low molecular weight gelators (LMWGs) make the LMWGs and the molecular gels highly …

Synthesis And Characterization Of Multifunctional Transition Metal Oxide Nanoparticles Through A Modified Sol-Gel Method With Application In Energy Storage, Julien Lombardi

Dissertations, Theses, and Capstone Projects

The Synthesis of transition metal oxide nanoparticles has been studied in great detail over the many years. The most studied transition metal oxide nanoparticles are perovskites of the ABO₃ stoichiometry (A and B = transition metal) and more recently double perovskite crystal structures of the AA’BO₆ or A₂BB’O₆ stoichiometry due to the many different properties arising from the many different combinations of elements possible. These materials have proven potentially useful in many fields, but due to properties such as ferroelectricity and ferromagnetism, the desire to integrate these materials into electronics is ever growing. Many synthesis …

Minimalistic Peptide-Based Supramolecular Systems Relevant To The Chemical Origin Of Life, Daniela Kroiss

Dissertations, Theses, and Capstone Projects

All forms of life are based on biopolymers, which are made up of a selection of simple building blocks, such as amino acids, nucleotides, fatty acids and sugars. Their individual properties govern their interactions, giving rise to complex supramolecular structures with highly specialized functionality, including ligand recognition, catalysis and compartmentalization. In this thesis, we aim to answer the question whether short peptides could have acted as precursors of modern proteins during prebiotic evolution. Using a combination of experimental and computational techniques, we screened a large molecular search space for peptide sequences that are capable of forming supramolecular complexes with adenosine …

The Parmodulin Nrd-21 Is An Allosteric Inhibitor Of Par1 Gq Signaling With Improved Anti-Inflammatory Activity And Stability, Disha M. Gandhi, Ricardo Rosas Jr., Eric Greve, Kaitlin Kentala, N'Guessan D.-R, Diby, Vladyslava A. Snyder, Allison Stephans, Teresa H.W. Yeung, Saravanan Subramaniam, Elliot Dimilo, Khia E. Kurtenbach, Leggy A. Arnold, Hartmut Weiler, Chris Dockendorff

Chemistry Faculty Research and Publications

Novel analogs of the allosteric, biased PAR1 ligand ML161 (parmodulin 2, PM2) were prepared in order to identify potential anti-thrombotic and anti-inflammatory compounds of the parmodulin class with improved properties. Investigations of structure-activity relationships of the western portion of the 1,3-diaminobenzene scaffold were performed using an intracellular calcium mobilization assay with endothelial cells, and several heterocycles were identified that inhibited PAR1 at sub-micromolar concentrations. The oxazole NRD-21 was profiled in additional detail, and it was confirmed to act as a selective, reversible, negative allosteric modulator of PAR1. In addition to inhibiting human platelet aggregation, it showed superior anti-inflammatory activity to …

Environmental Assessment Of Arsenic And Mercury Levels At The Garfield Mill Site, Calico, California, Steven Gregory Thorp

Electronic Theses, Projects, and Dissertations

Environmental impacts of mining at Calico, California, are poorly understood in comparison to the details of its history of silver production. Human health risks associated with arsenic from the lode rock, as well as mercury from the silver milling process, include central nervous system damage, organ failure, and death. To quantify the potential human health risk and manage remediation of this site, tailings from the Garfield Mill site were digitally mapped and chemically analyzed by portable x-ray fluorescence, which permitted volumetric estimates of total mill tailings and the arsenic and mercury budget, as well as identification of anomalies in the …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Synthesis Of Stimuli-Responsive Programmable Polymers Through Ring-Opening–Metathesis Cross-Metathesis (Rom-Cm), Courtney S. Dziewior, Sharon M. S. Strickland, Ping Li, Ken D. Shimizu

Journal of the South Carolina Academy of Science

Stimuli-responsive polymers can change their physical and/or chemical properties in response to external stimuli. These polymers have found great success in a number of important areas including molecular gels and biomedical engineering, as well as success in applications such as targeted drug delivery and biosensors. We have been working toward the development of programmable polymers that remember the response after a stimulus is withdrawn. To this end, we set out to synthesize specific functional monomers. While different types of reactions could potentially result in the desired target monomer, we studied the ring-opening metathesis–cross-metathesis reaction (ROM-CM). Previous work of ours synthesized …

The Effect Of Confinement On Fe2o3 Nanoparticles In Free Diffusion And With A Horizontal Magnetic Field, Patrick Simonson, Ashely Rice, Gabrielle Seymore, Ana Oprisan

Journal of the South Carolina Academy of Science

We investigated the magnitude of the confinement effect's influence on the free diffusion of Iron Oxide Fe₂O₃ in pure water contained in cells of different volumes and also that of an applied magnetic field. A shadowgraph apparatus consisting of a super luminous diode (SLD) source, a CCD camera, and achromatic lenses was used to record and analyze the changing indices of refraction due to the presence of concentration-driven fluctuations as the solution diffuses. Extracted frames from this recording were processed through a Differential Dynamic Algorithm (DDA) that determined the dynamics of the process, such as the structure …

Studying Near-Critical And Super-Critical Fluids In Reduced Gravity, Christian Hawkins, Ana Oprisan, Carole Lecoutre-Chabot, Yves Garrabos, Daniel Beysens

Journal of the South Carolina Academy of Science

Critical and supercritical fluids have a variety of applications, from use as machine lubricants in high pressure or high temperature environments to the manufacturing of materials such as aerogel. The optical properties of fluids undergo rapid changes near the critical point resulting in a rapid increase in turbidity known as critical opalescence. These optical changes can be used to probe the universality of critical behavior. As a fluid approaches the critical point, the compressibility rapidly increases. In a gravitational field, this increase in compressibility leads to near-critical fluids stratifying by phase and density, making it difficult to observe the optical …

Chronic Exposure To Complex Metal Oxide Nanoparticles Elicits Rapid Resistance In Shewanella Oneidensis Mr-1, Stephanie L. Mitchell, Natalie V. Hudson-Smith, Meghan S. Cahill, Benjamin N. Reynolds, Seth D. Frand, Curtis M. Green, Chenyu Wang, Mimi N. Hang, Rodrigo Tapia Hernandez, Robert J. Hamers, Z. Vivian Feng, Christy L. Haynes, Erin E. Carlson

Faculty Authored Articles

Engineered nanoparticles are incorporated into numerous emerging technologies because of their unique physical and chemical properties. Many of these properties facilitate novel interactions, including both intentional and accidental effects on biological systems. Silver-containing particles are widely used as antimicrobial agents and recent evidence indicates that bacteria rapidly become resistant to these nanoparticles. Much less studied is the chronic exposure of bacteria to particles that were not designed to interact with microorganisms. For example, previous work has demonstrated that the lithium intercalated battery cathode nanosheet, nickel manganese cobalt oxide (NMC), is cytotoxic and causes a significant delay in growth of Shewanella …

Anisotropic Singlet Fission In Single Crystalline Hexacene, Dezheng Sun, Gang-Hua Deng, Bolei Xu, Enshi Xu, Xia Li, Yajing Wu, Yuqin Qian, Yu Zhong, Colin Nuckolls, Avetik R. Harutyunyan, Hai-Lung Dai, Gugang Chen, Hanning Chen, Yi Rao

Chemistry and Biochemistry Faculty Publications

Singlet fission is known to improve solar energy utilization by circumventing the Shockley-Queisser limit. The two essential steps of singlet fission are the formation of a correlated triplet pair and its subsequent quantum decoherence. However, the mechanisms of the triplet pair formation and decoherence still remain elusive. Here we examined both essential steps in single crystalline hexacene and discovered remarkable anisotropy of the overall singlet fission rate along different crystal axes. Since the triplet pair formation emerges on the same timescale along both crystal axes, the quantum decoherence is likely responsible for the directional anisotropy. The distinct quantum decoherence rates …

Chemistry And Biochemistry News, Georgia Southern University

Biochemistry, Chemistry & Physics: News & Publications (2012-2023)

• Dr. Carpenter receives COSM Excellence in Teaching Award-2019

Convective Instabilities Derived From Dissipation Of Chemical Energy, Reuben H. Simoyi, Matthew W. Eskew

Chemistry Faculty Publications and Presentations

Oxidation reactions of a series of organosulfur compounds by chlorite are excitable, autocatalytic, and exothermic and generate a lateral instability upon being triggered by the autocatalyst. This article reports on the convective instabilities derived from the reaction of chlorite and thiourea in a Hele-Shaw cell. Reagent concentrations used for the development of convective instabilities delivered a temperature jump at the wave front of 2.1 K. The reaction zone was 2 mm and due to normal cooling after the wave front, this induced a spike rather than the standard well-studied front propagation. Localized spatiotemporal patterns develop around the wave front. This …