Digital Commons Network^™

Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth Mcneel

LSU Doctoral Dissertations

Sodium deoxycholate (NaDC) is a small bile salt that was used in this dissertation to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC. These solutions respectively yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), …

A Galactomannoglucan Derived From Agaricus Brasiliensis: Purification, Characterization And Macrophage Activation Via Mapk And Ikappab/Nfkappab Pathways, Yanqing Zhang, Danting Liu, Leilei Fang, Xiaotong Zhao, Aimin Zhou, Junbo Xie

Chemistry Faculty Publications

In this study, a novel galactomannoglucan named as TJ2 was isolated from Agaricus brasiliensis with microwave extraction, macroporous resin, ion exchange resin and high resolution gel chromatography. TJ2 is composed of glucose, mannose and galactose in the ratio 99.2:0.2:0.6. Infrared spectra (IR), methylation analysis and nuclear magnetic resonance spectra indicated that TJ2 mainly contained a b-(1?3) – linked glucopyranosyl backbone. Interestingly, TJ2 significantly promoted RAW264.7 cell proliferation, and was able to activate the cells to engulf E. coli. In addition, TJ2 induced the expression of Interleukin 1b (IL-1b), Interleukin 6 (IL-6), tumor necrosis factor a (TNF-a) and cyclooxygenase-2 (Cox-2) in …

Cooperative Standing-Horizontalstanding Reentrant Transition For Numerous Solid Particles Under External Vibration, Satoshi Takatori, Hikari Baba, Takatoshi Ichino, Chwen-Yang Shew, Kenichi Yoshikawa

Publications and Research

We report the collective behavior of numerous plastic bolt-like particles exhibiting one of two distinct states, either standing stationary or horizontal accompanied by tumbling motion, when placed on a horizontal plate undergoing sinusoidal vertical vibration. Experimentally, we prepared an initial state in which all of the particles were standing except for a single particle that was placed at the center of the plate. Under continuous vertical vibration, the initially horizontal particle triggers neighboring particles to fall over into a horizontal state through tumbling-induced collision, and this effect gradually spreads to all of the particles, i.e., the number of horizontal particles …

Aerogen Bonds Formed Between Aeof2 (Ae = Kr, Xe) And Diaziness: Comparisons Between Σ-Hole And Π-Hole Complexes, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The interaction between KrOF2 or XeOF2 and the 1,2, 1,3, and 1,4 diazines is characterized chiefly by a Kr/Xe···N aerogen bond, as deduced from ab initio calculations. The most stable dimers take advantage of the σ-hole on the aerogen atom, wherein the two molecules lie in the same plane. The interaction is quite strong, as much as 18 kcal mol-1. A second class of dimer geometry utilizes the π-hole above the aerogen atom in an approximate perpendicular arrangement of the two monomers; these structures are not as strongly bound: 6-8 kcal mol-1. Both sorts of dimers contain auxiliary CH···F H-bonds …

Sphingomyelin And Gm1 Influence Huntingtin Binding To, Disruption Of, And Aggregation On Lipid Membranes, Maxmore Chaibva, Xiang Gao, Pranav Jain, Warren A. Campbell, Shelli L. Frey, Justin Legleiter

Chemistry Faculty Publications

Huntington disease (HD) is an inherited neurodegenerative disease caused by the expansion beyond a critical threshold of a polyglutamine (polyQ) tract near the N-terminus of the huntingtin (htt) protein. Expanded polyQ promotes the formation of a variety of oligomeric and fibrillar aggregates of htt that accumulate into the hallmark proteinaceous inclusion bodies associated with HD. htt is also highly associated with numerous cellular and subcellular membranes that contain a variety of lipids. As lipid homeostasis and metabolism abnormalities are observed in HD patients, we investigated how varying both the sphingomyelin (SM) and ganglioside (GM1) contents modifies the interactions between htt …

Detection And Characterization Of The Tin Dihydride (Snh2 And Snd2) Molecule In The Gas Phase, Tony C. Smith, Dennis J. Clouthier

Chemistry Faculty Publications

The SnH₂ and SnD₂ molecules have been detected for the first time in the gas phase by laser-induced fluorescence (LIF) and emission spectroscopic techniques through the ùB₁–X̃¹A₁ electronic transition. These reactive species were prepared in a pulsed electric discharge jet using (CH₃)₄Sn or SnH₄/SnD₄ precursors diluted in high pressure argon. Transitions to the electronic excited state of the jet-cooled molecules were probed with LIF, and the ground state energy levels were measured from single rovibronic level emission spectra. The LIF spectrum of SnD_{2 …}

Analysis Of Veterinary Drug Residues In Imported And Domestic Crawfish Using Liquid Chromatography—Mass Spectrometry, Emily Kate Wall

LSU Master's Theses

Aquaculture production has greatly increased over the past few decades, and will continue to grow as the world fisheries become overfished and demand for seafood increases. With increased production comes more intense cultivation methods and heavy use of formulated feeds that may contain veterinary drug residues. Currently no antibiotics are allowed in the U.S. for crawfish aquaculture; yet, detectable levels of various antibiotics have been found in imported seafood samples.The FDA is responsible for testing aquaculture products entering the United States, but only has the capabilities to test a minimal amount of those imports. Additionally, for crawfish there is only …

E‑Cigarette Airflow Rate Modulates Toxicant Profiles And Can Lead To Concerning Levels Of Solvent Consumption, Tetiana Korzun, Maryana Lazurko, Tetiana Korzun, Ian Munhenzva, Kelley Barsanti, Yilin Huang, R. Paul Jensen, Jorge O. Escobedo, Wentai Luo, David H. Peyton, Robert M. Strongin

Chemistry Faculty Publications and Presentations

Electronic cigarettes enabling enhanced airflow have grown in popularity in recent years. The objective of this study is to show that flow rates modulate the levels of specific aerosol toxicants produced in electronic cigarettes. Flow rates used in various laboratory investigations involving e-cigarettes have varied widely to date, and can thus promote interlaboratory variability in aerosol product profiles. The thermal decomposition of hydroxyacetone and glycolaldehyde is less favorable at lower temperatures, supporting the observations of these products at higher flow rates/lower heating coil temperatures. Higher temperatures promote the formation of acetaldehyde from hydroxyacetone and formaldehyde from both hydroxyacetone and glycolaldehyde. …

Spermidine-Regulated Biosynthesis Of Heat-Stable Antifungal Factor (Hsaf) In Lysobacter Enzymogenes Oh11, Yuan Chen, Fengquan Liu, Liangcheng Du

Liangcheng Du Publications

Heat-Stable Antifungal Factor (HSAF) and its analogs are antifungal natural products produced by the biocontrol agent Lysobacter enzymogenes. The production of HSAF is greatly influenced by environmental stimuli and nutrients, but the underlying molecular mechanism is mostly unclear. Here, we found that HSAF production in L. enzymogenes OH11 is strictly controlled by spermidine, which is the most prevalent triamine in bacteria. When added into OH11 cultures, spermidine regulated the production of HSAF and analogs in a concentration-dependent manner. To verify the role of spermidine, we deleted LeSDC and LeADC genes, encoding S-adenosylmethionine decarboxylase and arginine decarboxylase, respectively, that are the …

Biomimetic Macromolecules For Macrophage Targeting And Modulation, Joshua Whited

ETD Archive

Carbohydrate recognition has come to the forefront of biological aiming to uncover the mechanisms of physiological and pathological processes. Cell surface glycans are involved in processes including cellular adhesion, cell signaling, and immune response. A new approach for profiling cell surface glycans has great potential for a wide range of biomedical applications. Lectins have been conventionally used to determine the structure and function of glycoproteins, however, their numbers are still restricted compared to the number of glycan structures. Boronic acid has proven a remarkable small molecule capable of binding diols in aqueous solution. This interaction indicates boronic acid derived molecules …

Oxidation Of Ferrocene Derivatives With Dibenzoyl Peroxide And Meta-Chloroperoxybenzoic Acid, Jos M. Halstead

ETD Archive

The chemical oxidation of ferrocene and related derivatives (RFc) via organic peroxides solvated in acetonitrile was studied spectrophotometrically by varying concentration and temperature to determine kinetics and activation parameters. The reaction rate of ferrocene with dibenzoyl peroxide depends strongly on whether electron withdrawing or donating substituents are present. Products were analyzed and the effect of different solvents on reactivity were studied. The rate law was first order in both oxidant and reductant, and steric and solvent effects are consistent with outer sphere electron transfer (ET) as the rate-controlling step. B3YLP calculations were conducted to determine reorganization energies using Marcus theory …

Audiobook Of A World From Dust, Ben Mcfarland

Faculty Open Access Books

A World From Dust is a popular science book about the chemical sequence behind the evolution of creation.

It’s about how geology, biology, and chemistry worked together over billions of years, providing a hidden order under the random flow of genes and lava and water.

It’s about the chemical job that each element takes up in life, and how that job is predictable from its place on the periodic table.

It can be told as the story of many elements: how iron and sulfur gave a spark of life; how manganese was a key for oxygen; and how copper and …

Large Effect Quantitative Trait Loci For Salicinoid Phenolic Glycosides In Populus: Implications For Gene Discovery, Scott A. Woolbright, Brian J. Rehill, Richard L. Lindroth, Stephen P. Difazio, Gregory D. Martinsen, Matthew S. Zinkgraf, Gerard J. Allan, Paul Keim, Thomas G. Whitham

Faculty & Staff Scholarship

Genomic studies have been used to identify genes underlying many important plant secondary metabolic pathways. However, genes for salicinoid phenolic glycosides (SPGs)—ecologically important compounds with significant commercial, cultural, and medicinal applications—remain largely undescribed. We used a linkage map derived from a full-sib population of hybrid cottonwoods (Populus spp.) to search for quanti- tative trait loci (QTL) for the SPGs salicortin and HCH-salicortin. SSR markers and primer sequences were used to anchor the map to the V3.0 P. trichocarpa genome. We discovered 21 QTL for the two traits, including a major QTL for HCH-salicortin (R2 = .52) that colocated with a …

Combining Semi-Synthesis With Plant And Microbial Biocatalysis: New Frontiers In Producing A Chemical Arsenal Against Cancer†, Samuel Gary, Janet Adegboye, Brian Popp, Jean-Christophe Cocuron, Brooklyn Woodrum, Nik Kovinich

Faculty & Staff Scholarship

Natural products (NPs) that exhibit anticancer activities are frequently not potent enough to be used clinically as therapeutics. Semi-synthesis and metabolic engineering are promising approaches for producing more efficacious derivatives of anticancer NPs (ACNPs), but each technique alone can be inefficient at obtaining specific ACNP derivatives that may be suspected to have enhanced anticancer activity. Here, we demonstrate that the methods of semi-synthesis and biocatalysis can be used as modules in succession and in different combinations to produce 6,8-dibromogenkwanin, a derivative of the ACNP apigenin. Further, we demonstrated that soybean seed coats can be used as a biocatalyst to convert …

Chemical Applications Of Transition Metal Nanomaterials: Nanoscale Toughening Mechanism Of Molybdenum Disulfide-Epoxy Nanocomposites And Mammalian Toxicity Of Silver Nanoparticles, John David Ryan

Browse all Theses and Dissertations

The emerging world of nanotechnology has been of great interest within the last few decades. In this regard, nanomaterials have since been implemented in a number of commercial applications including: aerospace technology, coatings, sensors, and biomedical technology. This work aimed to elucidate upon the applications of transition metal nanomaterials in two separate experimental studies. The first of these studies involved the investigation of two-dimensional molybdenum disulfide (MoS2) nanoparticles, and their role in the toughening mechanism of epoxy composites. Two separate exfoliation techniques were implanted to target the influence surface chemistry of the nanomaterial and solvent quality had on the bulk …

Metabolic And Transcriptional Modules Independently Diversify Plasma Cell Lifespan And Function, Wing Y. Lam, Arijita Jash, Cong-Hui Yao, Lucas D'Souza, Rachel Wong, Ryan M. Nunley, Gordon P. Meares, Gary J. Patti, Deepta Bhattacharya

Faculty & Staff Scholarship

Plasma cell survival and the consequent duration of immunity vary widely with infection or vaccination. Using fluorescent glucose analog uptake, we defined multiple developmentally independent mouse plasma cell populations with varying life- spans. Long-lived plasma cells imported more fluo- rescent glucose analog, expressed higher surface levels of the amino acid transporter CD98, and had more autophagosome mass than did short-lived cells. Low amino acid concentrations triggered re- ductions in both antibody secretion and mitochon- drial respiration, especially by short-lived plasma cells. To explain these observations, we found that glutamine was used for both mitochondrial respira- tion and anaplerotic reactions, yielding …

Lesson Plan: How Sweet It Is… The Effects Of Sucrose (Table Sugar) On The Body, Sheryl Hemkin

1. Sucrose

No abstract provided.

Structure Of The Ambrosia Beetle (Coleoptera: Curculionidae) Mycangia Revealed Through Micro-Computed Tomography, You Li, Yongying Ruan, Matthew T. Kasson, Edward L. Stanley, Conrad P.D.T Gillett, Andrew J. Johnson, Mengna Zhang, Jiri Hulcr

Faculty & Staff Scholarship

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) rely on a symbiosis with fungi for their nutrition. Symbiotic fungi are preserved and transported in specialized storage structures called mycangia. Although pivotal in the symbiosis, mycangia have been notoriously difficult to study, given their minute size and membranous structure. We compared the application of novel visualization methods for the study of mycangia, namely micro-computed tomography (micro-CT) and laser ablation tomography (LATscan) with traditional paraffin sectioning. Micro-CT scanning has shown the greatest promise in new organ discovery, while sectioning remains the only method with sufficient resolution for cellular visualization. All three common types …

Spontaneous Dna Damage To The Nuclear Genome Promotes Senescence, T Redox Imbalance And Aging, Andria R. Robinson, Matthew J. Yousefzadeh, Tania A. Rozgaja, Jin Wang, Xuesen Li, Jeremy S. Tilstra, Chelsea H. Feldman, Siobhan Q. Gregg, Caroline H. Johnson, Erin M. Skoda, Marie-Celine Frantz, Harris Bell-Temin, Hannah Pope-Varsalona, Aditi U. Gurkar, Luigi A. Nasto, Rena A.S. Robinson, Heike Fuhrmann-Stroissnigg, Jolanta Czerwinska, Sara J. Mcgowan, Nadiezhda Cantu-Madellin, Jamie B. Harris, Salony Maniar, Mark A. Ross, Christy E. Trussoni, Nicholas F. Larusso, Eugenia Cifuentes-Pagano, Patrick J. Pagano, Barbara Tudek, Nam V. Vo, Lora H. Rigatti, Patricia L. Opresko, Donna B. Stolz, Simon C. Watkins, Christin E. Burd, Claudette M. St, Croix, Gary Siuzdak, Nathan A. Yates, Paul D. Robbins, Yinsheng Wang, Peter Wipf, Eric E. Kelley, Laura J. Neidernhofer

Faculty & Staff Scholarship

Accumulation of senescent cells over time contributes to aging and age-related diseases. However, what drives senescence in vivo is not clear. Here we used a genetic approach to determine if spontaneous nuclear DNA damage is sufficient to initiate senescence in mammals. Ercc1-/Δ mice with reduced expression of ERCC1-XPF endonuclease have impaired capacity to repair the nuclear genome. Ercc1-/Δ mice accumulated spontaneous, oxidative DNA damage more rapidly than wild-type (WT) mice. As a consequence, senescent cells accumulated more rapidly in Ercc1-/Δ mice compared to repair-competent animals. However, the levels of DNA damage and senescent cells in Ercc1-/Δ mice never exceeded that …

Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions, Jiangyue Miao

Electronic Theses and Dissertations

The focus of this research project lies in the development of new methodology in the field of Brønsted acid catalysis enabling rapid synthesis of medicinally relevant compounds. It is foreseen that small molecule sulfonic acids evaluated in this research project will unveil new asymmetric carbon carbon bond forming reactions between substrates hitherto unexplored with Brønsted acid catalysis. It has been established that strong Brønsted acids, such as phosphoric acids, are capable of mediating highly selective transformations operating through unique mechanistic manifolds.

Specific focus for the sulfonic acid catalysts was geared towards asymmetric coupling reactions with synthetically useful precursors such as …

Indoleamine 2,3-Dioxygenase And Its Therapeutic Inhibition In Cancer, George C. Prendergast, William Paul Malachowski, Arpita Mondal, Peggy Scherle, Alexander J. Muller

Chemistry Faculty Research and Scholarship

The tryptophan catabolic enzyme indoleamine 2,3-dioxygenase-1 (IDO1) has attracted enormous attention in driving cancer immunosuppression, neovascularization, and metastasis. IDO1 suppresses local CD8 + T effector cells and natural killer cells and induces CD4 + T regulatory cells (iTreg) and myeloid-derived suppressor cells (MDSC). The structurally distinct enzyme tryptophan dioxygenase (TDO) also has been implicated recently in immune escape and metastatic progression. Lastly, emerging evidence suggests that the IDO1-related enzyme IDO2 may support IDO1-mediated iTreg and contribute to B-cell inflammed states in certain cancers. IDO1 and TDO are upregulated widely in neoplastic cells but also variably in stromal, endothelial, and innate …

Progress Toward The Synthesis Of Novel Bacterial Topoisomerase Inhibitors Derived From Fluoroquinolones. N-1 Amine Derivatives, Luke Burroughs, Joshua Kuperus, Evamarie Medendorp, Michael Barbachyn

Summer Research

Bacterial resistance to current antibiotics is a growing problem across the globe. The CDC reported that the estimated minimum illnesses caused by antibiotic resistance in the year 2013 was over 2 million, resulting in about 23,000 deaths in the U.S. 1 In 2014, the Obama administration released an executive order mandating that research be conducted to identify solutions to the bacterial resistance problem, especially in Gram-negative bacteria. One antibiotic series that has shown some promise are the fluoroquinolones. Fluoroquinolones have been on the market for years, with a current reference example being moxifloxacin. Fluoroquinolones (FQs) work by targeting DNA gyrase …

Synthesis Of Trisubstituted Indolizines: Optimization And Scope Studies, Matthew D. Rossler, Colin T. Hartgerink, Carolyn E. Anderson

Summer Research

Indolizines are a versatile heterocyclic core, found frequently in pharmaceutical targets, for a wide variety of therapeutic areas, including: anti-bacterial1 and anti-tumor,2 in addition to targets against Alzheimer’s disease,3 asthma,4 erectile dysfunction,5 and inflammation related to respiratory or cardiovascular disease

Sequestered Alkaloid Defenses In The Dendrobatid Poison Frog Oophaga Pumilio Provide Variable Protection From Microbial Pathogens, K. J. Hovey, E. M. Seiter, Erin E. Johnson, Ralph Saporito

2018 Faculty Bibliography

Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in dendrobatid poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect these frogs. Herein, we examined …

Lesson Plan: It’S Not Just The Smoke - The Effects Of Nicotine On The Body, Sheryl Hemkin

5. Nicotine

No abstract provided.

Lesson Plan: Small And Powerful – The Effects Of Ethanol From Consumable Alcohol On The Body, Sheryl Hemkin

4. Ethanol

No abstract provided.

Reduction Of Ruviºn To Ruiii-Nh3 By Cysteine In Aqueous Solution, Qian Wang, Wai-Lun Man, William W. Y. Lam, Shek-Man Yiu, Man-Kit Tse, Tai‐Chu Lau

Faculty of Science & Technology (THEi)

The reduction of metal nitride to ammonia is a key step in biological and chemical nitrogen fixation. We report herein the facile reduction of a ruthenium(VI) nitrido complex [(L)RuVI(N)(OH2)]+ (1, L = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion) to [(L)RuIII(NH3)(OH2)]+ by l-cysteine (Cys), an ubiquitous biological reductant, in aqueous solution. At pH 1.0–5.3, the reaction has the following stoichiometry: [(L)RuVI(N)(OH2)]+ + 3HSCH2CH(NH3)CO2 → [(L)RuIII(NH3)(OH2)]+ + 1.5(SCH2CH(NH3)CO2)2. Kinetic studies show that at pH 1 the reaction consists of two phases, while at pH 5 there are three distinct phases. For all phases the rate law is rate = k2[1][Cys]. Studies on the effects of acidity …

Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts

Chemistry Publications

Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing …

Nucleation And Growth Of Gold Nanoparticles Initiated By Nanosecond And Femtosecond Laser Irradiation Of Aqueous [Aucl4]-, Collin Rodrigues, Julian A. Bobb, Mallory G. John, Sergey Fisenko, M. S. El-Shall, Katharine M. Tibbetts

Chemistry Publications

Irradiation of aqueous [AuCl4]with 532 nm nanosecond (ns) laser pulses produces monodisperse (PDI = 0.04) 5 nm Au nanoparticles (AuNPs) without any additives or capping agents via a plasmon- enhanced photothermal autocatalytic mechanism. Compared with 800 nm femtosecond (fs) laser pulses, the AuNP growth kinetics under ns laser irradiation follow the same autocatalytic rate law, but with a significantly lower sensitivity to laser pulse energy. The results are explained using a simple model for simulating heat transfer in liquid water and at the interface with AuNPs. While the extent of water superheating with the ns laser is smaller compared to …

Flexible Robotic Actuators, Stephen A. Morin, Robert F. Shepherd, Adam Stokes, Filip Ilievski, Ramses V. Martinez, Jamie L. Branch, Carina R. Fish, Lihua Jin, Rui M. D. Nunes, Zhigang Suo, George M. Whitesides

Department of Chemistry: Faculty Publications

Systems and methods for providing flexible robotic actuators are disclosed. Some embodiments of the disclosed subject matter include a soft robot capable of providing a radial deflection motions; a soft tentacle actuator capable of providing a variety of motions and providing transportation means for various types of materials; and a hybrid robotic system that retains desirable characteristics of both soft robots and hard robots. Some embodiments of the disclosed subject matter also include methods for operating the dis closed robotic systems.