Physical Sciences and Mathematics Commons^™

A Review Of Baobab (Adansonia Digitata) Products: Effect Of Processing Techniques, Medicinal Properties And Uses, Donatien Kabore, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Clarise Compaoré, Mamoudou H. Dicko Prof., Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

A general literature review including the effect of processing techniques, medicinal value and uses of baobab tree is reported in this manuscript. Baobab tree has multi-purpose uses, as it produces food and non-food products such as medicines, fuel, timber, fodder. Every part of the baobab tree is reported to be useful. The seeds, leaves, roots, flowers, fruit pulp and bark of baobab are edible. Baobab leaves are used in the preparation of soup. Seeds are used as a thickening agent in soups, but they can be fermented and used as a flavouring agent or roasted and eaten as snacks. The …

Analytic Derivative Couplings Between Configuration-Interaction-Singles States With Built-In Electron-Translation Factors For Translational Invariance, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

Chemistry Faculty Publications and Presentations

We present a method for analytically calculating the derivative couplings between a pair of configuration-interaction-singles (CIS) excited states obtained in an atom-centered basis. Our theory is exact and has been derived using two completely independent approaches: one inspired by the Hellmann-Feynman theorem and the other following from direct differentiation. (The former is new, while the latter is in the spirit of existing approaches in the literature.) Our expression for the derivative couplings incorporates all Pulay effects associated with the use of an atom-centered basis, and the computational cost is minimal, roughly comparable to that of a single CIS energy gradient. …

Design And Synthesis Of Cationic Steroid Antimicrobial Compounds, Synthesis Of Glycolipids Recognized By Natural Killer T Cells And Development Of Tlr-1, Tlr-6 Heterodimer Binders And Studies Of Their Immunology Activities, Yanshu Feng

Theses and Dissertations

Cationic steroid antimicrobial agents (CSAs) are a family of bile acid derivatives. These compounds are amphiphilic and mimic endogenous antimicrobial peptides. The antimicrobial activities of CSA-13 have been investigated and due to portent bactericidal activities and low toxicity, a large amount of CSA-13 is demanded for clinic trails and other antimicrobial applications. During our studies, we optimized the synthetic route of CSA-13, so that it can be prepared at the kilogram, even in tons scale. We investigated three routes and one of them is suitable for industry, because only recrystallization is needed in the synthesis. Natural killer T cells (NKT …

Investigating The Thermal Stability And Cation Ordering In Layered Cathode Lixmo2 (X ≤ 1; M = Co, Mn, Ni) Materials For Li-Ion Rechargeable Batteries And Studying The Ferroelectric Properties Of Linbo3 Nanoparticles, Debasish Mohanty

University of New Orleans Theses and Dissertations

In recent years, transition metal oxides have drawn extensive attention because of their wide application in electronic, memory, battery, informatics, and optoelectronics devices. In this dissertation, we have studied two different types of oxide materials which are technologically important: LiMO 2 (M = Co, Mn, Ni), has served as cathode materials in the rechargeable battery, and LiNbO3, has wide application in ferroelectric devices such as electronics, non-volatile memories, and thin film capacitors. LiMO2 was synthesized and characterized to understand the correlation between capacity fading and thermal stability relating to the microstructures. Our results showed that delithiated (charged) LiCoO2, forms a …

Synthesis And Antifungal Evaluation Of Spirostane Saponins, Sunil Upadhyay

University of New Orleans Theses and Dissertations

Methods for the preparation of novel antifungal saponins have been investigated in

order to further explore their medicinal utility and provide the opportunity to synthesize

their derivatives.

Through this work, several partially protected stereoisomers of Cholestane,

Androstane and Spirostane have been prepared which could be used for the synthesis of

various saponin derivatives in order to discover novel saponin based antifungal agent.

Various mono and disaccharide derivatives of these steroids have been synthesized and

evaluated for their antifungal activity against four pathogenic fungal strains. Among the

various derivatives maltose derivatives were found to have the best antifungal activity.

However there …

Synthesis Of Chemical Models Of Hydrolase Enzymes For Intramolecular Catalysis., Cornelius Ndi Ndi

Electronic Theses and Dissertations

Most nuclease enzymes can hydrolyze phosphoester bonds (in DNA and RNA) by using metal ions cofactors that coordinate and activate water molecules in the enzymes' active sites. However, there are some hydrolase enzymes (including nucleases) that can function without the aid of metal ions. 2,6-Di(1H-imidazol-2-yl)phenol, a model compound for hydrolase enzyme, was synthesized by the reaction between ethylenediamine and dimethyl-3-carboxysalicylate, initially resulting in the formation of diimidazoline. The diimidazoline was subsequently aromatized to the diimidazole by dehydrogenation over palladium. The overall reaction yield was low; therefore, other dehydrogenation transformation reactions were tried but all failed to improve the …

Mesoporous Functionalized Materials For Post-Combustion Carbon Dioxide Capture., Kolade Omoniyi Ojo

Electronic Theses and Dissertations

Novel highly functionalized hybrid organic-inorganic materials were synthesized by polycondensation of bis[3-(trimethoxysilyl)propyl]amine in presence of cationic and anionic surfactants. Reaction media strongly affected gelation time. Thus, in basic media gelation occurred immediately while acid increased gelation time. Material structures were studied by IR spectroscopy, porosimetry, XRD, and SAXS methods. In spite of the absence of an inorganic linker, obtained bridged silsesquioxanes had mesoporous structure. A material prepared in the presence of dodecylamine as a template had higher surface area and narrow pore size distribution while the use of sodium dodecylbenzene sulfate resulted in formation of mesopores with wide size ranges. …

Using Electrochemical Method To Study The Interaction Between Dna And A Compound Known To Have Anticancer Property., Alexander Kamasah

Electronic Theses and Dissertations

The interaction of 4-(1'-[8'-(1''-pyrenyl)naphthyl])-2,6-diaminopyridine bis-glycamide bishydrocholride known to have anticancer properties with deoxyribonucleic acid (DNA) had been studied on a modified gold electrode by self-assembled monolayer using cyclic voltammetry. K₄Fe (CN)₆ was used as a probe to obtain electrochemical information on the electrode surface.

A bare gold (Au) electrode was modified with cysteamine and our results showed no change in the limiting steady state current as compared to the bare Au electrode. There was a reduction in the steady state current after the modification of the gold electrode with DNA. Immobilization of the DNA modified gold electrode …

A Study Of The Effects Of Titanium Dioxide Nanoparticles On The Fluorescent Intensity Of Fluorescent Compounds In The Presence Of Known Quenchers., Vivian Dzigbodi Koka

Electronic Theses and Dissertations

Titanium Dioxide is a naturally occurring oxide of titanium. It has a wide range of uses in commercial products for providing whiteness and opacity. It has photocatalytic properties and can also be used to produce electricity in its nanoparticles form. This research is focused on investigating the effect of titanium dioxide nanoparticles in analysis of compounds using luminescence-based techniques. Quenching, which is one of the basic problems of fluorescent measurements, was studied in the presence of molecular oxygen and methyl iodide. The rutile phase of titanium dioxide nanoparticles was synthesized by the acid hydrolysis of titanium isobutoxide at low temperatures …

Synthesis And Biological Evaluation Of Aeruginosin Based Compounds And Self-Assembly Of Glucosamine Based Compounds, Navneet Goyal

University of New Orleans Theses and Dissertations

Aeruginosins are a family of marine natural products containing mostly non-proteogenic amino acids. These compounds contain a common 2-carboxy-6-hydroxy-octaindole (Choi) rigid bicyclic structure. Many aeruginosins are inhibitors for enzymes involved in the blood coagulation cascade, such as thrombin and Factor VIIa. In order to understand the structure activity relationship (SAR) of the aeruginosins and to discover novel anticoagulants with potentially improved inhibitory and pharmacokinetic properties, in the first part of my thesis I have discussed, synthesis of a series of novel analogs of aeruginosin 298-A, in which the Choi will be replaced with L-proline and oxygenated Choi analogs, and the …

Synthesis And Applications Of Luminescent Quantum Dots In Bioassays, Venkata Ramana Kethineedi

University of New Orleans Theses and Dissertations

Luminescent quantum dot (QD) based probes have gained significance in the last decade for optical imaging of cells, tissues and in bioassays as alternatives to conventional organic fluorophores. The main objective of my PhD dissertation was to develop luminescent quantum dot based bioassays for real time monitoring of enzyme activity and simultaneous detection of several biomarkers. The quantum dot based bioassays developed will be potential tools in identification and diagnosis of several ailments that interfere with normal living conditions of human beings.

In Chapter 2 new liposome encapsulated quantum dot based fluorescence resonance energy transfer (FRET) probes have been fabricated …

Development Of A Novel Electron-Transfer Secondary Reaction Matrix, Characterization Of The Site–Specificity Of Novel Bilin-Lyase, And Fundulus Grandis Protein Expression Investigation Using Mass Spectrometry, Mohamed N. Boutaghou

University of New Orleans Theses and Dissertations

Reported in this dissertation are the results of investigations performed at the New Orleans Center for Mass Spectrometry at the University of New Orleans. The projects that are detailed in the coming pages take on a variety of subjects, but a common thread is that each employs matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to solve a problem. Fundamental aspects of MALDI in-plume ionization are implicated in the introduction of a newly developed electron-transfer secondary ionization matrix. The remaining projects are related to the ever expanding field of proteomics. Mass spectrometry was used to investigate the site specificity of a newly …

Self-Assemblies Driven By The Hydrophobic Effect, Haiying Gan

University of New Orleans Theses and Dissertations

Water is a simple molecule but is an essential part of life. One key aspect of the properties of water is the hydrophobic effect, and whilst there is an appreciation of this phenomenon at the macro-scale (raindrops falling off leaves) and the micro-scale (the structure of cellular systems), a complete understanding at the molecular level still eludes science. Addressing this issue, our studies involve synthetic supramolecular compounds that assemble in water via the hydrophobic effect.

First of all, a novel water-soluble deep-cavity cavitand was synthesized. It possesses four endo methyl groups on top rim of the cavitand, eight water-solubilizing carboxylic …

Fabrication Of Chemically Modified Nanometer-Sized Gold Electrodes And Their Application In Electrocatalysis At Pt Nanoparticles., Jude Lakbub

Electronic Theses and Dissertations

Hydrogen evolution via proton reduction occurs at a high rate at the surface of Pt than at Au electrodes. Using cyclic voltammetry, chemically modified nanometer-sized Au electrodes, prepared by the Laser-Assisted Puller Method, were employed to examine current amplification by electrocalysis at Pt nanoparticles adsorbed on the modified Au electrode surfaces. The electrodes were modified with Self-Assembled Monolayers (SAMs) of cysteamine and soaked in Pt colloid solutions overnight. Monitoring the decrements of the characteristic steady-state catalytic current for proton reduction indicated that aggregates of Pt nanoparticles are adsorbed on the cysteamine monolayers and desorb from them particle by particle. The …

Synthesis Of N-(Substituted Phenyl) Acetamides., Landon Zink

Undergraduate Honors Theses

No abstract.

Determination Of Select Metal Ions In Commercially Available Conventional And Organic Baby Foods., Neva S. Winters

Electronic Theses and Dissertations

The goal of this study is to determine whether or not there is an appreciable difference between concentrations of various metal ions present in conventionally grown and processed and organically grown and processed baby foods. Two prominent, commercially available brands were chosen to undergo comparative studies between both their own conventional and organic varieties of second stage green beans and carrots. Samples were tested for cadmium, calcium, iron, lead, nickel, and zinc. Two containers of each variety of baby food were sampled in triplicate, with purchases of foods being made in separate areas to ensure that each set came from …

Modified Organoclay Containing Chelating Ligand For Adsorption Of Heavy Metals In Solution., Mary Akuyea Addy

Electronic Theses and Dissertations

Presence of a chelating ligand in the clay structure significantly improves its ability to immobilize heavy metals from contaminated sludge or wastewater. Two-step modification procedure comprising sequential pillaring and grafting of chelating agent to the modified clay is involved.

Montmorillonite and kaolin were chosen as typical examples of expandable and non-expandable clays, correspondingly. Modifications with silica and ferric oxide were targeted on development of mesoporous structure. Laboratory tests of the organoclay efficiency for purification of wastewater were conducted with the most promising sample, i.e. organoclay with the highest specific loading of chelating agent. Experiments were conducted with model wastewater containing …

Synthesis Of Resveratrol Ester Derivatives Using Selective Enzymatic Hydrolysis., Marian Osei-Mensah

Electronic Theses and Dissertations

Resveratrol, a naturally derived stilbene, is an interesting compound mostly talked about recently because for its anti-cancer properties. Unfortunately it has some shortcomings due to its low bioavailability and low solubility in water. For this reason, my research is to overcome resveratrol's drawbacks by improving its bioavailability and hydrophilicity. My research is focused on syntheses of novel derivatives of resveratrol such as 3, 5-di-O-isobutyroyl resveratrol and 3, 5-di-O-hexanoyl resveratrol using lipase catalyzed hydrolysis. Therefore, the tri-acylated resveratrols 3, 5, 4'-tri-O-isobutyroyl resveratrol and 3, 5,4'-tri-O-hexanoyl resveratrol were first synthesized.

3,5,4'-tri-O-isobutyroyl resveratrol and 3,5,4'-tri-O-hexanoyl resveratrol were then hydrolyzed using lipase (C. …

Survey Of Flavonoids And Their Distribution In Different Kinds Of Onions Using High Performance Liquid Chromatography And Gas Chromatography Mass Spectrometry., Archana Racharla

Electronic Theses and Dissertations

This research is done to determine the distribution of flavonoids in diverse varieties of onions (commercial and wild onions). Reflux extraction method was done on dried onions and the abstracts were analyzed subsequently by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GCMS). Statistical calculations were done to see if there are significant differences in the varieties of onions studied from the chromatographic profiles obtained. The chromatograms obtained were patterned using visual observations, scatter plot study, correlation co-efficient, and ANOVA to evaluate the significant difference of the distribution of flavonoids in varieties of onions. The organic white onions seem …

Crystal Lattice Desolvation Effects On The Magnetic Quantum Tunneling Of Single-Molecule Magnets, G Redler, Christos Lampropoulos, S Datta, C Koo, T C. Stamatatos, N E. Chakov, G Christou, S Hill

Christos Lampropoulos

High-frequency electron paramagnetic resonance (HFEPR) and alternating current (ac) susceptibility measurements are reported for a new high-symmetry Mn12 complex, [Mn12O12(O2CCH3)16(CH3OH)4]⋅CH3OH. The results are compared to those of other high-symmetry spin S=10 Mn12 single-molecule magnets (SMMs), including the original acetate, [Mn12(O2CCH3)16(H2O)4]⋅2CH3CO2H⋅4H2O, and the [Mn12O12(O2CCH2Br)16(H2O)4]⋅4CH2Cl2 and [Mn12O12(O2CCH2But)16(CH3OH)4]⋅CH3OH complexes. These comparisons reveal important insights into the factors that influence the values of the effective barrier to magnetization reversal, Ueff, deduced on the basis of ac susceptibility measurements. In particular, we find that variations in Ueff can be correlated with the degree of disorder in a crystal which can be controlled by desolvating (drying) …

Spin Dynamics In Single-Molecule Magnets Combining Surface Acoustic Waves And High-Frequency Electron Paramagnetic Resonance, F Macià, J Lawrence, S Hill, J M. Hernandez, J Tejada, P V. Santos, Christos Lampropoulos, G Christou

Christos Lampropoulos

We report an experimental technique that integrates high-frequency surface acoustic waves (SAWs) with high-frequency electron paramagnetic resonance (HFEPR) spectroscopy in order to measure spin dynamics on fast time scales in single-molecule magnets. After the system is driven out of equilibrium by triggering magnetic avalanches, or simply by heating with short SAW pulses, the evolution of the spin populations within fixed energy levels is measured using HFEPR spectroscopy.

Alignment Of Magnetic Anisotropy Axes In Crystals Of Mn12 Acetate And Mn12-Tbuac Molecular Nanomagnets: Angle-Dependent Ac Susceptibility Study, E Burzurí, Ch Carbonera, F Luis, D Ruiz-Molina, Christos Lampropoulos, G Christou

Christos Lampropoulos

We report the results of angular-dependent ac susceptibility experiments performed on two derivatives of Mn12 single-molecular magnets: the well-known Mn12 acetate, which contains disordered acetic acid molecules in interstitial sites of the crystal structure and Mn12-tBuAc, for which solvent molecules are very well ordered in the structure. Our results show (a) that the angular variation is very similar in the two compounds investigated and compatible with a maximum misalignment of the anisotropy axes of less than 3° and (b) that the tunneling rate is faster for the better ordered Mn12-tBuAc compound. These experiments question interstitial disorder as the dominant origin …

Realization Of Random-Field Ising Ferromagnetism In A Molecular Magnet, Bo Wen, P Subedi, Lin Bo, Y Yeshurun, M P. Sarachik, A D. Kent, A J. Millis, Christos Lampropoulos, G Christou

Christos Lampropoulos

The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn12-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase at ∼0.9 K. With increasing magnetic field applied transverse to the easy axis, a marked change is observed in the temperature dependence of the susceptibility, and the suppression of ferromagnetism is considerably more rapid than predicted by mean-field theory for an ordered single crystal. Our results can instead be fit by a Hamiltonian for a random-field Ising ferromagnet in a transverse magnetic field, where the randomness derives from the intrinsic distribution of locally tilted magnetic easy axes …

Effects Of Quantum Mechanics On The Deflagration Threshold In The Molecular Magnet Mn12 Acetate, F Macià, J M. Hernandez, J Tejada, S Datta, S Hill, Christos Lampropoulos, G Christou

Christos Lampropoulos

We report experimental studies of the stability of a Mn12-Ac crystal against magnetic avalanches as a function of the magnitude and direction of the magnetic field, as well as a function of temperature. Strong evidence for quantum effects associated with this phenomenon is seen in the (Hz,Hx) metastability diagram. The data provide further support to the theory of magnetic deflagration.

Experimental Determination Of The Weiss Temperature Of Mn12-Ac And Mn12-Ac-Meoh, Christos Lampropoulos, Shiqi Li, Lin Bo, Bo Wen, M P. Sarachik, P Subedi, A D. Kent, Y Yeshurun, A J. Millis, S Mukherjee, G Christou

Christos Lampropoulos

We report measurements of the susceptibility in the temperature range from 3.5 to 6.0 K of a series of Mn12-ac and Mn12-ac-MeOH samples in the shape of rectangular prisms of length lc and square cross section of side la. The susceptibility obeys a Curie-Weiss law, χ=C/(T−θ), where θ varies systematically with sample aspect ratio. Using published demagnetization factors, we obtain θ for an infinitely long sample corresponding to intrinsic ordering temperatures Tc≈0.85 K and ≈0.74 K for Mn12-ac and Mn12-ac-MeOH, respectively. The difference in Tc for two materials that have nearly identical unit cell volumes and lattice constant ratios suggests …

Reactions With Platinum (Ll) Complexes And Selenium-Containing Amino Acids, Stephanie Robey

Mahurin Honors College Capstone Experience/Thesis Projects

We have reacted [Pt(Me₄en)(D₂O)₂]²⁺ [Me₄En=N,N,N’N’-tetramethylethylenediamine] with Selenomethionine (SeMet), Methionine (Met), and Methylselenocysteine (MeSeCys). When MeSeCys was reacted with [Pt(Me₄en)(D₂O)₂]²⁺, we observed both stereoisomers of Se,N chelates, as well as [Pt(Me₄en)(MeSeCys)Cl]⁺ from ­¹­H NMR Spectroscopy; the latter formed due to the presence of Cl^- in the solution. Both isomers of the chelate seemed to form proportionally to one another, not favoring a specific stereoisomer. Eventually the [Pt(Me₄en)(MeSeCys)Cl]⁺ products became Se,N chelates. We incubated SeMet with …

Study Of The Vaporization Enthalpies By Correlation-Gas Chromatography, Dmitry Lipkind

Dissertations

The focus of this thesis is on the measurement and collection of thermodynamic and physical property data, including vaporization, fusion, and sublimation enthalpies and vapor pressures of large n-alkanes, nitrogen heterocycles and related compounds by a technique developed in our laboratory referred to as correlation-gas chromatography (C-GC). These thermodynamic data are of importance to several disciplines that include chemical engineering, as well as the pharmaceutical and the petrochemical industries. Vapor pressures of large hydrocarbons are fundamental data required in the petroleum industry to develop thermodynamic models for dealing with crude oil. Environmental chemists and engineers use vapor pressures and vaporization …

Influence Of Weak Interactions On Supramolecular Binding: Characterization Of Cucurbituril Complexes With Alkylmonoammonium Ions Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Ruijan Shi

Theses and Dissertations

This thesis focuses on using mass spectrometry-based techniques for characterizing the structure and behavior of cucurbituril complexes in the gas phase. Both solvent and counter ion effects can be completely eliminated in the gas phase and the intrinsic interactions in the system are directly shown in the experimental results. Chapter 1 introduces the structures, properties and host-guest chemistry of cucurbituril, and FTICR mass spectrometry including instrumentation, performance and working principles. Two mass spectrometry-based methods for supramolecular characterization, sustained off-resonance irradiation collision induced dissociation (SORI CID) and ion molecule equilibrium measurements, are also discussed in this chapter. Chapter 2 characterizes the …

Mechanism Of G Protein Beta-Gamma Assembly Mediated By Phosducin-Like Protein 1, Chun Wan Jeffrey Lai

Theses and Dissertations

G-protein coupled receptor signaling (GPCR) is essential for regulating a large variety of hormonal, sensory and neuronal processes in eukaryotic cells. Because the regulation of these physiological responses is critical, GPCR signaling pathways are carefully controlled at different levels within the cascade. Phosducin-like protein 1 (PhLP1) can bind the G protein βγ dimer and participate in GPCR signaling. Recent evidence has supported the concept that PhLP1 can serve as a co-chaperone of the eukaryotic cytosolic chaperonin complex CCT/TRiC to mediate G βγ assembly. Although a general mechanism of PhLP1-mediated G βγ assembly has been postulated, many of the details about …

Relating Dynamic Protein Interactions Of Metallochaperones With Metal Transfer At The Single-Molecule Level, J. J. Benítez, A. M. Keller, D. L. Huffman, Liliya A. Yatsunyk, A. C. Rosenzweig, P. Chen

Chemistry & Biochemistry Faculty Works

Metallochaperones undertake specific interactions with their target proteins to deliver metal ions inside cells. Understanding how these protein interactions are coupled with the underlying metal transfer process is important, but challenging because they are weak and dynamic. Here we use a nanovesicle trapping scheme to enable single-molecule FRET measurements of the weak, dynamic interactions between the copper chaperone Hahl and the fourth metal binding domain (MBD4) of WDP. By monitoring the behaviors of single interacting pairs, we visualize their interactions in real time in both the absence and the presence of various equivalents of Cu(1+). Regardless of the proteins' metallation …