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Articles 391 - 420 of 619
Full-Text Articles in Chemistry
Phytochemical Analyses Of Bioactive Compounds In The Roots Of Cassia Alata Linn And The Anti-Angiogenic Evaluation Of Rhein As A Therapeutic Agent Against Breast Cancer Cells, Vivian Esther Fernand
Phytochemical Analyses Of Bioactive Compounds In The Roots Of Cassia Alata Linn And The Anti-Angiogenic Evaluation Of Rhein As A Therapeutic Agent Against Breast Cancer Cells, Vivian Esther Fernand
LSU Doctoral Dissertations
The research presented in this dissertation includes the novel phytochemical analysis of root extracts of Cassia alata L. and the anti-angiogenic evaluation of rhein in the treatment of breast cancer. To conduct these studies a combination of analytical techniques were employed, namely, chromatographic, spectroscopic, and bioanalytical. The first part of this research is focused on the phytochemical analysis of C. alata root extracts. A high performance liquid chromatography method was developed and validated for the determination of six phenolic compounds in the root extracts. The investigated compounds were identified by their ultraviolet spectra. Additionally, the presence of these phenolics was …
Beta-Diketone And -Ketoenamine-Based Organic Building Blocks For Porous Metal Organic-Materials, Yoseph Solomon Marcos
Beta-Diketone And -Ketoenamine-Based Organic Building Blocks For Porous Metal Organic-Materials, Yoseph Solomon Marcos
LSU Doctoral Dissertations
This dissertation focuses on synthesis of multifunctional â-diketone and â-ketoenamine ligands and their reaction with metal ions, mainly Cu2+. Several new bi-, tri-, and tetrafunctional organosilicon â-diketone building blocks with â-diketone groups at approx. 109° (tetrahedral) were successfully synthesized. New thiophene based bifunctional ligands where the â-diketones are at about 145° are also reported here. We also prepared a range of new aryl-â-ketoenamines from their analogous â-diketones in very high yield using a simple microwave-assisted procedure. Reactions of organosilicon tris(â-diketone)s LH3 with Cu2+ were explored quite intensively. These ligands form metal-organic-polyhedra (MOPs) that are soluble in organic solvents, and insoluble …
A Novel Synthesis And Characterization Of Fluorescein Isothiocyanate Labeled Poly(Styrenesulfonate Sodium Salt), Xiaowei Tong
A Novel Synthesis And Characterization Of Fluorescein Isothiocyanate Labeled Poly(Styrenesulfonate Sodium Salt), Xiaowei Tong
LSU Master's Theses
The diffusion of polyelectrolytes in low-salt or salt-free aqueous solutions is a controversial question. It has been intensively discussed since it was discovered in 1978. Most previous experimental data were obtained from dynamic light scattering (DLS), whose precision, however, was reduced by stringent sample preparation and weak scattering of polyelectrolyte in low-salt solution. For the most commonly studied polyelectrolyte, poly(styrenesulfonate sodium salt) (NaPSS), the harsh polymerization condition and the manufacturing procedure lead to hydrophobic defects and aggregations, which also block a correct insight about the diffusion of polyelectrolyte. In contrast to DLS, fluorescence photobleaching recovery (FPR) directly looks on the …
Substituted Bis(Beta-Diketones) For Molecular Squares, Jace Sandifer
Substituted Bis(Beta-Diketones) For Molecular Squares, Jace Sandifer
LSU Master's Theses
Our group has been synthesizing porous supramolecular metal-organic molecules using multidentate β-diketones as ligands. For example, m-phenylenebis(acetylacetone) (m-pbaH2, 1) and m-phenylenebis(dipropionylmethane) (m-pbprH2, 2) were readily converted to the molecular squares Cu4(m-pba)4 (6) and Cu4(m-pbpr)4 (7), which bind guests such as 4,4’-bpy and C60.1 However, 6 and 7 are only soluble in a few solvents, limiting their use in practical applications. It is therefore necessary to derivatize the ligand with different functional groups in order to improve solubility and adjust host-guest properties. Simple alkoxy derivatives should prove useful in testing this idea as they would be relatively chemically inert and should …
A Study Of The Self-Assembly Of Water-Soluble Porphyrins In Aqueous Solution, Javoris Hollingsworth
A Study Of The Self-Assembly Of Water-Soluble Porphyrins In Aqueous Solution, Javoris Hollingsworth
LSU Master's Theses
In nature, self-assembly processes of biologically active organic molecules often occur, resulting in formation of dimers and higher oligomers of various and sometimes complex structures. This natural occurrence of self-organization has been the subject of research, with the aim of understanding and possibly modulating the aggregation behavior of biological molecules. The meso-tetrakis(4-phosphonatophenyl) porphyrin, H2TPPP was synthesized, purified, and characterized. Its self-assembly was studied in aqueous solutions as a function of pH and time. The variations on the λmax and shape of the Soret band of this porphyrin in the absorption spectra when altering the pH indicated the pH dependency in …
The Syntheses Of Methyl Jasmonate And Analogs Of Alpha-Methylene-Gamma-Butyrolactone Utilizing Titanium Medicated Cyclocarbonylation, Steve O. Lawrence
The Syntheses Of Methyl Jasmonate And Analogs Of Alpha-Methylene-Gamma-Butyrolactone Utilizing Titanium Medicated Cyclocarbonylation, Steve O. Lawrence
LSU Doctoral Dissertations
From its humble beginnings as a novel carbon–carbon bond forming reaction, the Pauson–Khand reaction has lead to the synthetic development of a variety of natural products. One particular variation of the Pauson–Khand reaction was called the hetero Pauson–Khand. This reaction differs from the normal Pauson–Khand reaction because the reaction employs an intramolecular titanium mediated cycloaddition using enal and enones instead of alkenes and alkynes functional groups to prepare a variety of natural products. These natural products usually contain a bicyclic cyclopentenone core. Because the new ring contains a hetero atom, the name hetero Pauson–Khand was coined. Alpha–Methylene–Gamma–Butyrolactones posses a wide …
Computational Studies On Fatty Acid Synthesis: From Mechanisms To Drug Design, Matthew Edward Mckenzie
Computational Studies On Fatty Acid Synthesis: From Mechanisms To Drug Design, Matthew Edward Mckenzie
LSU Doctoral Dissertations
The first committed steps of the Fatty Acid synthesis pathway involves the de/carboxylation reactions of biotin. By understanding this step, potential novel antimicrobial agents could be discovered. The current tools of drug discovery can only help the research in finding and modifying potential hits. Finding a lead candidate from these programs are often equated to finding a needle in a haystack, which is due to the many assumptions used in molecular docking. The fundamental reaction kinetics can not be described by these techniques and a detailed study of the decarboxylation reaction is investigated using ab initio molecular dynamics. In this …
Merged Electrospray Ionization Mass Spectrometry, Jianan Dong
Merged Electrospray Ionization Mass Spectrometry, Jianan Dong
LSU Doctoral Dissertations
Ambient ionization allows the analysis of materials in their native environment without sample preparation by creating ions outside the mass spectrometer. The goal of this research was to develop new ambient ionization techniques for application to solids, liquids and particles under ambient conditions. Samples to be analyzed were directly merged with an electrospray of droplets, and then ionized and detected by a mass spectrometer. An ion trap mass spectrometer was modified with a nanoelectrospray source and configured for three experiments: merged electrospray ionization of dry particles, merged electrospray ionization of combustion products, and infrared laser desorption/ablation using electrospray for post-ionization. …
On-Line Laser Desorption/Ionization Mass Spectrometry, Damien A. Narcisse
On-Line Laser Desorption/Ionization Mass Spectrometry, Damien A. Narcisse
LSU Doctoral Dissertations
Interfaces for on-line laser desorption/ionization mass spectrometry are presented in this dissertation. An on line laser desorption interface allows samples to be introduced directly into the mass spectrometer for high-throughput applications. For this research, a linear time of flight mass spectrometer was constructed with an ionization source designed to accept various laser desorption interfaces. A ball inlet interface was used for continuous analyte deposition at atmospheric pressure and vacuum ionization. A solvent-based cleaning system and a separate capillary for MALDI matrix delivery was utilized for continuous on line sampling with the ball inlet interface. Microfluidic devices were brought into contact …
Applying Scanning Probe Microscopy For The Investigation Of Molecular Self-Assembly Mechanisms And Properties Of Designed Nanomaterials, Algernon Tremayne Kelley
Applying Scanning Probe Microscopy For The Investigation Of Molecular Self-Assembly Mechanisms And Properties Of Designed Nanomaterials, Algernon Tremayne Kelley
LSU Doctoral Dissertations
Scanning probe microscopy (SPM) for conducting surface characterizations of nanomaterials and molecular self-assembly processes is emerging as an important contribution in nanotechnology, especially towards the design of molecular electronic devices. Another area of importance is the characterization of the properties of nanomaterials for fundamental understanding of structure-function inter-relationships. Understanding the properties and behavior of molecules and finding approaches to control surface self-organization through nanolithography provides essential information for the development of workable applications for nanotechnology. This dissertation describes the methodologies of AFM for characterizing molecules and nanostructures produced with scanning probe lithography (SPL). Automated software for nanografting and nanoshaving produce …
Peptide Targeting Of Platinum Anti-Cancer Drug And Synthesis Of Water Soluble Monofunctional Pt(Ii) Complexes Useful For Biological Labeling, Margaret W. Ndinguri
Peptide Targeting Of Platinum Anti-Cancer Drug And Synthesis Of Water Soluble Monofunctional Pt(Ii) Complexes Useful For Biological Labeling, Margaret W. Ndinguri
LSU Doctoral Dissertations
Platinum has been used as an inorganic medicinal agent with various applications such as anti cancer agents. Several new targeted Pt(II) conjugates were synthesized having the NGR and LHRH targeting motif. The platinum conjugates bearing the NGR motif revealed selective delivery and destruction of cancer cells that had CD13 receptors compared to untargeted carboplatin drug. The development of targeted chemotherapeutic has opened a new approach for efficient delivery of antitumor toxins with minimal exposure to normal cells. Several peptide sequences are known to have the ability to target tumors, for instance NGR motif which home specifically in solid tumors and …
Amyloid Aggregation-Mitigating Peptides As Potential Alzheimer's Drugs, Cyrus Kipkurui Bett
Amyloid Aggregation-Mitigating Peptides As Potential Alzheimer's Drugs, Cyrus Kipkurui Bett
LSU Doctoral Dissertations
Neuronal cytotoxicity observed in Alzheimer¡¦s disease (AD) is linked to the aggregation of £]-amyloid peptide (A£]) into toxic forms. Increasing evidence points to oligomeric species as the neurotoxic species compared to fibrils; disruption or inhibition of A£]ƒnself-assembly into oligomeric or fibrillar forms remains a viable therapeutic strategy to reduce A£] neurotoxicity. Amyloid aggregation mitigating peptides (AAMPs) were designed based on the A£]ƒn¡§hydrophobic core¡¨ A£]17-20, with C£\,£\-disubstituted amino acidsƒnƒv£\£\AAs) added into this core as disrupting agents. The number, distribution, and side chain functionality of £\£\AAs incorporated into the mitigator sequence was found influences the resultant aggregate morphology as indicated by ex-situ …
Computational Studies Of The Properties Of Copper Oxide Clusters And The Reactions Of Phenol And Chlorinated Phenols With Copper Oxide Clusters, Gyun-Tack Bae
LSU Doctoral Dissertations
We used ab initio simulations and calculations to study the structures and stabilities of copper oxide clusters, CunOn (n=1-8) and CuOn (n=1-6). The lowest energy structures of neutral and charged copper oxide clusters were determined using primarily the B3LYP/LANL2DZ model chemistry. In CunOn clusters with n=1-8, a transition from planar to nonplanar geometries occurs at n=4. In CuOn clusters with n=1-6, all geometries of neutral, positively, and negatively charged clusters are planar or near planar structures. Selected electronic properties, including binding energies, ionization energies, and electronic affinities, were calculated and examined as a function of n. Stabilities were examined by …
Size Controlled Metal Oxide Nanoparticles:Synthesis, Characterization, And Application To Catalysis, Hongyi Wu
Size Controlled Metal Oxide Nanoparticles:Synthesis, Characterization, And Application To Catalysis, Hongyi Wu
LSU Doctoral Dissertations
The research in this dissertation focuses on the synthesis of size-controlled metal oxide nanoclusters (< 10 nm) on amorphous silica and their catalytic performance in thermal degradation of chlorinated benzenes with regard to the cluster size effect. Furthermore, with the concern that metal can condense as the nano-size nuclei core for particle growth in combustion process, a flow reactor was built to investigate the effect of metal oxide nanoparticles on the formation of soot in fuel-rich combustion. The synthesis of copper oxide nanoclusters was carried by calcination of silica impregnated with dendrimer-metal complexes. The 4th generation poly(propylene imine) dendrimer DAB-Am32 was used in this template-based method. The sizes of copper oxide nanoclusters were exquisitely controlled in the range of 1-5 nm with narrow size distribution by changing the stoichiometric ratio of metal ion to the terminal primary amines of dendrimer, the equivalent metal oxide loading on surface, and the impregnation procedure. XANES and XPS studies revealed that CuO was the dominant component of copper oxide nanoclusters. This method was also experimentally proven to be valid in the preparation of other metal oxide nanoparticles, e.g., Ni and Fe, and with other oxide substrates, e.g., titanium oxide. Chlorinated benzenes were selected as the model compound for studying the activity of metal (Cu and Fe) oxide catalysts with regard to their cluster sizes. Compared to the surrogate of coarse metal oxide samples, which was prepared by incipient wetness method, their nanosize analogues showed superior catalytic activity on the conversion of chlorinated benzenes under both pyrolytic and oxidative thermal condition. Furthermore, such catalytic size effect was also observed on the selectivity of products yields. Sooting combustion was performed using a two-zone flow reactor with precise control on experimental parameters. Gas suspended metal oxide nanoparticles were generated by burning off the organic backbone of the dendrimer-metal complexes in zone 1 and immediately transferred to zone 2, where the hydrocarbon combustion occurred. TEM results of the particulate sample collected at the outlet of reactor indicated that metal oxide nanoparticles promoted soot formation. GC/MS analysis of the extracted organic materials from soot samples suggested the formation of PAH was also promoted by metal addition as well.
Derivatization Of Porphyrins For Dna And Metal Ion Binding, Especially By Employing Secondary Sulfonamide Links, Janet Manono
Derivatization Of Porphyrins For Dna And Metal Ion Binding, Especially By Employing Secondary Sulfonamide Links, Janet Manono
LSU Doctoral Dissertations
Porphyrins are of exceptional importance in nature, science and technology: For instance, as ligands for metals in supramolecular synthesis, as photosenstizers in photodynamic therapy (PDT), and as building blocks for electronic devices. In addition to their application in cancer therapy, porphyrin species also exhibit antiviral activity. New meso-tetraarylporphyrins (TArP, Ar = -C6H4-) of the general formula, T(R1R2NSO2Ar)P, with R1 = N-py-n-CH2 (n = 2, 3 or 4) or SO3- and R2 = H or CH3 were synthesized. These groups were linked to the …
Capillary Electrophoretic Separations Of Enzyme Inhibitors With Activity-Based Detection, Xiaoyan Yan
Capillary Electrophoretic Separations Of Enzyme Inhibitors With Activity-Based Detection, Xiaoyan Yan
LSU Master's Theses
A technique for separating and detecting enzyme inhibitors was developed using capillary electrophoresis with an enzyme microreactor. The on-column enzyme microreactor was constructed using one or two NdFeB magnets in two configurations to immobilize alkaline phosphatase-coated superparamagnetic beads with diameters of 2.8 µm inside a capillary before the detection window. Enzyme inhibition assays were performed by injecting a plug of inhibitor into a capillary filled with an alkaline phosphatase substrate, AttoPhos. Product generated in the enzyme microreactor was detected by laser-induced fluorescence. Inhibitor zones electrophoresed through the capillary, passed through the enzyme microreactor, and were observed as negative peaks due …
Polymer-Based Microfluidic Devices For High Throughput Single Molecule Detection: Applications In Biological And Drug Discovery, Paul Ichide Okagbare
Polymer-Based Microfluidic Devices For High Throughput Single Molecule Detection: Applications In Biological And Drug Discovery, Paul Ichide Okagbare
LSU Doctoral Dissertations
The realization of high throughput sample processing has become a primary ambition in many research applications with an example being high throughput screening (HTS), which represents the first step in the drug discovery pipeline. Microfluidics is a viable platform for parallel processing of biochemical reactions to increase data production rates due to its ability to generate fluidic networks with a high number of processors over small footprints suitable for optical imaging. Single-molecule detection (SMD) is another technology which has emerged to facilitate the realization of high throughput data processing afforded by its ability to eliminate sample processing steps and generate …
Characterization And Transitions Of Asphalt Cement Composite Materials, Brent Harper Sellers
Characterization And Transitions Of Asphalt Cement Composite Materials, Brent Harper Sellers
LSU Master's Theses
Blends of a PG 64-22 asphalt with a range of load levels (0.2 — 20 wt %) of Sasobit® wax and a single loading of 2 wt % Elvaloy AM® were prepared and characterized. Sasobit® wax is a high molecular weight paraffinic wax produced commercially through the Fischer-Tropsch process. Elvaloy AM® is a reactive elastic terpolymer, comprised of ethylene, butyl acrylate and glycidyl methacrylate monomeric units. The blends were analyzed by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), x-ray diffraction, epifluorescence microscopy, scanning laser confocal microscopy, and dynamic shear rheology. Sasobit (1 wt %) composite material showed little difference …
Studies On The Effect Of Natural Organic Matter And Hydration On The Sorption And Desorption Of Trifluorinated Pesticides, Charisma Vinarao Lattao
Studies On The Effect Of Natural Organic Matter And Hydration On The Sorption And Desorption Of Trifluorinated Pesticides, Charisma Vinarao Lattao
LSU Doctoral Dissertations
This work was done in order to deepen our molecular level understanding of how soil organic matter (SOM) is assembled in a whole soil and to provide further insight on the effect of SOM assembly on the uptake and release of hydrophobic organic compounds. Various techniques, including ultraviolet absorbance, fluorescence, and total carbon analysis, demonstrate that hydration/solvation of SOM is kinetically controlled. Initial wetting of a soil releases the hydrophobic moieties that are located at the outer surface of SOM, and longer wetting times exfoliate more hydrophobic quinone type moieties that are present in the middle layer, which in turn …
Scanning Probe Microscopy Investigations Of (1) Arrays Of Cysteine-Coated Cds Nanoparticles And (2) Structures Formed During The Early Stages Of The Corrosion Of Copper Surfaces, Brian Robert Lewandowski
Scanning Probe Microscopy Investigations Of (1) Arrays Of Cysteine-Coated Cds Nanoparticles And (2) Structures Formed During The Early Stages Of The Corrosion Of Copper Surfaces, Brian Robert Lewandowski
LSU Doctoral Dissertations
Scanning probe microscopy (SPM) characterizations are becoming more prevalent for surface investigations due to their capabilities for obtaining structural information and physical measurements. New capabilities of SPM for studying and controlling nanoscale processes are emerging as valuable assets in research. A fundamental understanding of the interactions of surface reactions provides essential information for developing workable applications for nanotechnology. Two applications of SPM are discussed in this dissertation. The first investigation uses atomic force microscopy (AFM) for the characterization of nanostructures produced with a newly developed lithographic technique called “two-particle” lithography. This new technique is based on particle lithography for the …
Atom-Based Computer Simulation Studies Of Gas-To-Liquid Nucleation In Atmospherically Relevant Systems: Clarifying Discrepancies And Elucidating Mechanisms, Ricky Bendanillo Nellas
Atom-Based Computer Simulation Studies Of Gas-To-Liquid Nucleation In Atmospherically Relevant Systems: Clarifying Discrepancies And Elucidating Mechanisms, Ricky Bendanillo Nellas
LSU Doctoral Dissertations
For over a century, nucleation for all systems was thought simplistically to be a process that advances through the formation of critical clusters with a well-defined composition. Our results show intriguing nucleation mechanisms that challenge the aforementioned notion. We employed the simple TraPPE-UA (transferable potential for phase equilibria – united atom) force field and the AVUS-HR approach (a combination of aggregation-volume-bias Monte Carlo, umbrella sampling, and histogram reweighting), to investigate the homogeneous vapor-to-liquid nucleation of various nucleating systems. We found out that these systems could nucleate through a variety of unique non-ideal mechanisms. Alongside existing experimental investigations, this dissertation presents …
Iron Mediated Pecipitation Of Phenol: Protein Aggregates From Sugar Cane Juice, Lee R. Madsen Ii
Iron Mediated Pecipitation Of Phenol: Protein Aggregates From Sugar Cane Juice, Lee R. Madsen Ii
LSU Doctoral Dissertations
The Louisiana cane sugar industry is moving toward a vertically integrated arrangement where raw sugar producers will have an interest in refining. In the sugar refining process, raw sugar is affined to remove ~50 % of the color. The new refinery that will be built in Louisiana, however, will not include affining stations. To reduce costs of refining, either affining stations will need to be installed at each mill or new technologies that provide equivalent color reduction (~50% or ~750 IU) need to be implemented. As part of this dissertation a new technology for color reduction at raw sugar mills …
Fabrication Of Nanostructured Surfaces With Well-Defined Chemistry Using Particle Lithography, Jie-Ren Li
Fabrication Of Nanostructured Surfaces With Well-Defined Chemistry Using Particle Lithography, Jie-Ren Li
LSU Doctoral Dissertations
Natural self-assembly processes provide nanofabrication capabilities for designing surfaces with nanoscale control of surface chemistry and relative orientation of the nanomaterials on the surfaces. Particle lithography was used to produce periodic arrays of protein nanostructures. Monodisperse mesoparticles can be applied to rapidly prepare millions of uniform protein nanostructures on flat surfaces using the conventional benchtop chemistry steps of mixing, centrifuging, evaporation and drying. Nanopatterns of bovine serum albumin and staphylococcal protein A were produced with particle lithography. The immobilized proteins remain attached to the surface and form nanopatterns over micron areas corresponding to the thickness of a single layer of …
Synthesis Of A Dirhodium Tetraphosphine Catalyst And The Effect Of Various H2/Co Ratios On The Catalyst, Christina Joanne Sweeney
Synthesis Of A Dirhodium Tetraphosphine Catalyst And The Effect Of Various H2/Co Ratios On The Catalyst, Christina Joanne Sweeney
Honors Capstones
No abstract provided.
The Determination Of The Electronic Structure And Geometries Of Boron And Boron Mononitrogen Clusters Using An Adaptive, Kink-Based Path Integral Approach To Quantum Mechanics, Shawn Wilkinson
Honors Capstones
No abstract provided.
Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry For The Analysis Of Collected Bioaerosols, Alton John Dugas
Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry For The Analysis Of Collected Bioaerosols, Alton John Dugas
LSU Doctoral Dissertations
The goal of this dissertation was to demonstrate collection, detection and identification of microorganisms from bioaerosols using offline matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of proteins. MALDI-MS intact bacteria techniques were adapted for use with an orthogonal MALDI quadrupole-time-of-flight mass spectrometer. Results indicate the instrument is capable of analyzing intact whole-cells. The first phase was to evaluate three bioaerosol samplers, an Andersen N6 single-stage impactor (AI), a cyclone impactor, and a vacuum filter system. The samplers collected test bioaerosols using a constructed bioaerosol exposure chamber (BEC). The BEC allowed all three samplers to operate in parallel. Each …
Gas-Phase Formation Of Environmentally Persistent Free Radicals From Thermal Degradation Of Catechol, Hydroquinone, Phenols And Tobacco, Julien Gnonlonfoun Adounkpe
Gas-Phase Formation Of Environmentally Persistent Free Radicals From Thermal Degradation Of Catechol, Hydroquinone, Phenols And Tobacco, Julien Gnonlonfoun Adounkpe
LSU Doctoral Dissertations
Catechol, hydroquinone and Phenol are major constituents of the mainstream tobacco smoke. The toxicity of tobacco has been attributed to the ability of catechol and hydroquinone to undergo endogenous or exogenous redox cycling to form semiquinone type radicals responsible of Reactive Oxygen Species (ROS) formation. ROS such as hydroxyl radicals can cause severe oxidative stress on biological tissues and can provoke severe signaling pathways leading to cardiovascular and pulmonary dysfunctions and carcinogenesis. Given that semiquinone type radicals are organic radicals, characterized by their high instability and reactivity; it is somewhat surprising that they can live long enough mostly when associated …
A Study Of Rheological And Thermodynamic Properties Of Polymer-Clay Gels And Multilayered Films, Eduard Adrian Stefanescu
A Study Of Rheological And Thermodynamic Properties Of Polymer-Clay Gels And Multilayered Films, Eduard Adrian Stefanescu
LSU Doctoral Dissertations
The overall objective of the research presented here is to understand the nanoscopic and microscopic structures that exist in dispersions of laponite and montmorillonite in poly(ethylene oxide), (PEO) and to correlate their shear responses with the final structure and properties of multilayered nanocomposite films prepared from these dispersions. These structures were examined as a function of polymer molecular weight, polymer and clay concentrations, and type of clay used to prepare the nanocomposites. A sequence of shear and elongational rheological measurements is used to provide a more complete physical picture on the structure of polymer-clay hydrogels, while a combination of techniques …
Off-Line Maldi Mass Spectrometry Of Bioaerosols, Jae-Kuk Kim
Off-Line Maldi Mass Spectrometry Of Bioaerosols, Jae-Kuk Kim
LSU Doctoral Dissertations
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used for off-line analysis of bioaerosols. The overall goal of the work is to develop methods and instrumentation to minimize sample treatment and maximize sensitivity and selectivity for bioaerosol analysis. This work is divided into three parts: sample preparation, test bioaerosol analysis, and instrument development. Untreated silicon wafer substrates were used as an alternate to conventional stainless steel targets and proved to be excellent substrates for large molecule analyses as well as small molecule analyses with excellent spot-to-spot and shot-to-shot reproducibility, which is useful for high-throughput and automated sample analysis. MALDI sample preparation …
Investigation Of Antimonide Structure Types And The Structural Studies Of Molybdates, Dixie Plaisance Gautreaux
Investigation Of Antimonide Structure Types And The Structural Studies Of Molybdates, Dixie Plaisance Gautreaux
LSU Doctoral Dissertations
This dissertation highlights the investigation of ternary lanthanide antimonide structure types and their physical properties. In particular, these ternary phases allow for the systematic investigation of the structure in an effort to correlate structure and properties. The ternary antimonides are layered structures with two-dimensional square sheets or nets, which influence the properties of these materials. In an effort to determine how structural changes influence the physical properties, various single crystals of compounds relating to the orthorhombic CeNiSb3 structure have been grown and characterized. The layered CeNiSb3 structure consists of Sb sheets, NiSb6 distorted octahedra, and CeSb9 monocapped square anti-prisms. LnNi(Sn,Sb)3 …