Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- GUMBOS (2)
- Photochemistry (2)
- Spectroscopy (2)
- Synthesis (2)
- 1-3 anti diols (1)
-
- 1-3 syn diols (1)
- 31P NMR (1)
- 3rd generation (1)
- AFM (1)
- Aldehyde-water shift (1)
- Aliphatic primary alcohol (1)
- Amidine (1)
- Analyte discrimination (1)
- Ascarosides (1)
- Atomic force microscopy (1)
- BODIPY (1)
- Biological relevance (1)
- Biosynthesis (1)
- Blue light (1)
- Boron Functionalization (1)
- C-H bond functionalization (1)
- C. elegans (1)
- Caenorhabditis elegans (1)
- Cascade reaction-based (1)
- Catalyst (1)
- Chain-growth polymerization (1)
- Chemical biology (1)
- Chemical protein modification (1)
- Chlorination (1)
- Conjugated polymers (1)
Articles 1 - 22 of 22
Full-Text Articles in Physical Sciences and Mathematics
Single Molecule Electrophoresis And Optical Detection Using Thermoplastic Nanofluidic Devices: An Experimental And Simulation Study, Kumuditha Madushanka Weerakoon Ratnayake
Single Molecule Electrophoresis And Optical Detection Using Thermoplastic Nanofluidic Devices: An Experimental And Simulation Study, Kumuditha Madushanka Weerakoon Ratnayake
LSU Doctoral Dissertations
Nanofludic devices provide a great platform for single molecular analysis. The unique phenomena in nanoscale gained such interest in investigating the single molecular behavior in nanochannels. Sizes less than 200 nm in one or two-dimensional structures have lead to fascinating observations not accessible in microscale. When a single molecule translocates through a nanotube it interacts with channel walls by adsorption/ desorption, van der Waals interactions and hydrophilic interactions providing a mechanism for separation without any extra additives. Moreover, double layer thickness governed by the background electrolyte plays a vital role. We report single molecular electrophoresis phenomena in nanochannels and nanoslits …
Development Of Transition Metal-Catalyzed Polymerization Reactions And Their Applications For The Preparation Of Well-Defined Conjugated Polymer Architectures, Carlos Anthony Chavez
Development Of Transition Metal-Catalyzed Polymerization Reactions And Their Applications For The Preparation Of Well-Defined Conjugated Polymer Architectures, Carlos Anthony Chavez
LSU Doctoral Dissertations
The synthesis of conjugated polymers and design of complex materials based on them have become increasingly popular as the demand for low-cost efficient and processible optoelectronic and semiconducting devices escalates. While advanced applications of polymeric materials require some degree of sophistication, success can be achieved through careful consideration of polymerization techniques and methodologies. Controlling critical aspects of the polymerization process allows for synthesis of complex macromolecular architectures possessing unique and novel properties that may be worth of further comprehensive investigation. This dissertation primarily focuses on the development and preparation of well-defined hierarchical macromolecular architectures. The foundation of this work encompasses …
Design And Application Of Task-Specific Organic Salts For Chemical And Biochemical Sensing, Waduge Indika Subodha Galpothdeniya
Design And Application Of Task-Specific Organic Salts For Chemical And Biochemical Sensing, Waduge Indika Subodha Galpothdeniya
LSU Doctoral Dissertations
There is an increasing demand for development of new sensors and sensor strategies for accurate detection and discrimination of various analytes. In this regard, colorimetric and fluorometric sensor approaches have attracted considerable attention, primarily because they represent facile and inexpensive analytical tools. In this dissertation, I discuss the design and application of sensors and sensor arrays using task specific organic salts: ionic liquids (ILs) and a group of uniform materials based on organic salts (GUMBOS). As compared to typical ionic compounds, these two classes of organic salts exhibit relatively lower melting points due to bulky organic cations and/or anions. Interestingly, …
A Monte Carlo Approach To Studying The Hydrogen Storage Capabilities Of Potassium Magnesium Hydride (Kmgh3), Brandon L. Borill
A Monte Carlo Approach To Studying The Hydrogen Storage Capabilities Of Potassium Magnesium Hydride (Kmgh3), Brandon L. Borill
LSU Doctoral Dissertations
Grand Canonical Monte Carlo (GCMC) simulations and the weighted histogram analysis method (WHAM) were employed at selected temperatures and pressures in the study of the hydrogen storage capabilities of KMgH3. A specially tailored addition/removal algorithm was employed to add hydrogen directly at the lattice sites. Agreement between experimental results was obtained through GCMC simulations. WHAM type studies were employed to obtain probability distributions for the purpose of learning the probability of finding hydrogen atoms at specific temperatures and hydrogen pressures. The radial distribution function was employed to study the changes in the structure of KMgH3 for the selected model as …
Development Of New Linking Chemistry With The Fac-{Re(Co)3}+ Core For Eventual Applications In Radiopharmaceuticals In Imaging And Therapy, Aponsu Meregngna Pramuditha Lakmi Abhayawardhana
Development Of New Linking Chemistry With The Fac-{Re(Co)3}+ Core For Eventual Applications In Radiopharmaceuticals In Imaging And Therapy, Aponsu Meregngna Pramuditha Lakmi Abhayawardhana
LSU Doctoral Dissertations
The facile labeling of biomolecules with a radionuclide is a key goal in radiopharmaceutical development. This study explores two different ligand systems for fac-[Re(CO)3L]+ complexes, that could be used in bioconjugation. The first approach uses a tridentate ligand having a sulfonamide linkage and modeled on previously evaluated fac-[Re(CO)3(N(SO2R)dpa)]PF6 complexes. The present goal was to develop new related sulfonamide complexes with more hydrophilic ligands designed to avoid the bioavailability problems that would plague the N(SO2R)dpa ligand system. A series of fac-[Re(CO)3(N(SO2R)dien)]PF6 complexes with different R groups linked to the central nitrogen of a symmetric tridentate sulfonamides were synthesized with the aim …
Computational Studies On Bimetallic Catalysis And X-Ray Absorption Spectroscopy, Sayakkarage R. G. Fernando
Computational Studies On Bimetallic Catalysis And X-Ray Absorption Spectroscopy, Sayakkarage R. G. Fernando
LSU Doctoral Dissertations
Computational studies are very important to gain an insight into reaction mechanisms and in interpreting and understanding complicated experimental observations. This report contains a discussion on computational studies performed on bimetallic catalysis and on X-ray absorption spectroscopy of insulators. The viability of a bimetallic rhodium and cobalt catalysts for industrially important hydroformylation and aldehyde-water shift catalysis (AWS) is discussed. Density functional theory (DFT) studies were used for bimetallic catalysis and time-dependent DFT studies were used for excited state dynamics. These studies were performed using Gaussian 09 package and NWChem. Hydroformylation is experimentally performed in acetone and 30% water/acetone systems and …
On The Development Of Analytical Methodologies To Interrogate The Lipid Dynamics And Phase Transition Resulting From The Reduction Of Stimuli-Responsive Vesicles, James Edward Winter
On The Development Of Analytical Methodologies To Interrogate The Lipid Dynamics And Phase Transition Resulting From The Reduction Of Stimuli-Responsive Vesicles, James Edward Winter
LSU Doctoral Dissertations
The potential is great for liposome drug delivery systems that provide specific contents release at diseased tissue sites upon activation by upregulated enzymes; however, this potential will only come to fruition with mechanistic knowledge of the contents release process. NAD(P)H:quinone oxidoreductase type 1 (NQO1) is a target for reductively-responsive liposomes, as it is an enzyme upregulated in numerous cancer tissues and is capable of reducing quinone propionic acid (QPA) trigger groups to hydroquinones that self-cleave from dioleolylphosphatidylethanolamine (DOPE) liposome surfaces, thereby initiating contents release. This research targets the development of analytical methodologies to observe and characterize the dynamics and resulting …
Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer
Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer
LSU Doctoral Dissertations
This work in this dissertation explores how photoelectrons enter and exit atoms and molecules. The electron rescattering events which may occur during photoionization or photorecombination processes play a dominant role in the understanding of how photoelectrons enter and exit molecules, which is intrinsically linked to how chemical reactions occur. Chapters 3-4 of this dissertation present evidence of vibrational mode specific breakdown of the Franck-Condon Principle in the photoionization of low symmetry molecules, acrolein and the singly halogenated thiophenes, due to resonant and non-resonant electron rescattering dynamics. In Chapters 5-6, the disentanglement of the valence electronic structure, as well as evidence …
Nanoscale Gumbos: Size-Control, Characterization, And Applications As Enantioselective Molecularly Imprinted Polymers And Fluorescent Materials, Suzana Hamdan
LSU Doctoral Dissertations
Nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS) have been introduced into the scientific literature through many analytical, biological, and technological applications. These nanomaterials, referred to as nanoGUMBOS, have been shown to display a number of interesting properties including fluorescence, magnetism, tumor targeting, and optoelectronic properties. Herein, we present major studies on nanoGUMBOS including synthesis and size-control, chiral molecular imprinting in polymers, as well as investigation of optical properties and quantum yield of fluorescent semiconductor-based nanoGUMBOS. Various strategies were introduced for production of well-defined nanoGUMBOS. Specifically, several methods based on sonochemistry, microwave, cyclodextrin, and surfactant-assisted …
Platinum Complexes With Tridentate Ligands As Models For Active Monofunctional Anticancer Drugs, Chase Koby Andrepont
Platinum Complexes With Tridentate Ligands As Models For Active Monofunctional Anticancer Drugs, Chase Koby Andrepont
LSU Doctoral Dissertations
Pt(II) complexes bind preferentially at N7 of G residues of DNA, causing DNA structural distortions associated with anticancer activity. Some distortions induced by difunctional cisplatin are also found for monofunctional Pt(II) complexes with carrier ligands having bulk projecting toward the guanine base. This ligand bulk can be correlated with impeded rotation about the Pt–N7(guanine) bond. The objective of this study is to understand the influences of in-plane bulk of Pt(Ltri)G adducts (Ltri = tridentate carrier ligand, G = guanine derivative bound to a metal, but not tethered to another nucleobase). NMR spectroscopy provided conclusive evidence that Pt(Ltri)G (Ltri = di-(2-picolyl)amine …
Chemically Patterned Surfaces As Test Platforms To Study Magnetic And Solvent-Responsive Properties At The Nanoscale: Investigations Using Scanning Probe Microscopy, Shalaka Kulkarni
LSU Doctoral Dissertations
Chemically patterned surfaces were fabricated using a combination of molecular self-assembly and particle lithography to generate billions of nanostructures of organosilane self-assembled monolayers (SAMs). Monodisperse mesospheres were used as surface masks to prepare nanostructures on flat surfaces using the simple benchtop chemistry steps of mixing, centrifuging, evaporation, and drying. Periodic arrays of well-defined organosilane nanostructures serve as discrete surface sites for the selective deposition of polymers and magnetic nanoparticles.
In this dissertation, particle lithography approaches for surface patterning provide new directions for studying surface chemistry at the molecular-level using high resolution investigations with scanning probe microscopy (SPM). Atomic force microscopy …
Gumbos As Matrices For Matrix-Assisted Laser Desorption Ionization Time Of Flight Mass Spectrometry, Hashim Abdullah Al Ghafly
Gumbos As Matrices For Matrix-Assisted Laser Desorption Ionization Time Of Flight Mass Spectrometry, Hashim Abdullah Al Ghafly
LSU Doctoral Dissertations
This work involves the investigation of a group of uniform materials based on organic salts (GUMBOS) as matrices for matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF) for analysis of hydrophobic biomolecules. GUMBOS are new class of materials that show great promise as MALDI matrices because they are able to form a thin-layer on the MS target, thereby enhancing the sample homogeneity, signal intensity, and shot-to-shot reproducibility. The detection of hydrophobic peptides using MALDI-TOF MS remains a challenge because the majority of matrices utilized are hydrophilic thereby exhibiting low affinity for hydrophobic molecules. To address this, I …
The Electronic Structure Of Environmentally Persistent Free Radicals Formed On Metal Oxide Surfaces, Chad Allen Thibodeaux
The Electronic Structure Of Environmentally Persistent Free Radicals Formed On Metal Oxide Surfaces, Chad Allen Thibodeaux
LSU Doctoral Dissertations
We have investigated the electronic structure of environmentally persistent free radicals (EPFRs) formed on two different metal oxides: Cu(II)O and ZnO. Cu(II)O is known to be one of the most active metal oxides to form EPFRs. ZnO, however, forms the longest-lived EPFRs. First, we examined the adsorption of phenol on different crystal faces of ZnO. Ultraviolet photoelectron spectroscopy (UPS) shows direct evidence of charge transfer away from the ZnO to the phenol. This differs from the hypothesized mechanism of EPFR formation that says that an electron is transferred to the metal oxide. UPS difference spectra also shows that the phenol …
Synthesis, Characterization, And Evaluation Of Small Molecule-Based Fluorogenic Probes For The Detection Of Cellular Thiols, Rasika Ranatunga Nawimanage
Synthesis, Characterization, And Evaluation Of Small Molecule-Based Fluorogenic Probes For The Detection Of Cellular Thiols, Rasika Ranatunga Nawimanage
LSU Doctoral Dissertations
Fluorescence methods for disease diagnosis and detection of important analytes are becoming popular route as a technique, as they offer a simple non-invasive approach. Recently, many novel fluorophores and probes have been reported for selectively and sensitively detecting low abundance biological species in disease pathways. Biological thiols, such as glutathione, cysteine, and homocysteine, along with the smallest member hydrogen sulfide, are key thiol analytes in biological environments, and they play a vital role in living systems by maintaining the redox homeostasis of cells. Alteration of their ratios can cause cellular dysfunction and cell death. Furthermore, thiol levels in cells and …
Synthetic Methods Development Towards The Total Synthesis Of Chlorosulfolipids, Andres Villalpando
Synthetic Methods Development Towards The Total Synthesis Of Chlorosulfolipids, Andres Villalpando
LSU Doctoral Dissertations
The focus of this dissertation is the development of a novel chlorination reaction utilizing a triphosgene-amine based mixture towards the total synthesis of chlorosulfolipids, a subclass of naturally occurring organohalogen natural products. This novel, mild chlorination reaction will be utilized under a global chlorination strategy to chlorinate multiple alcohol substituents in one synthetic operation. Chapter one details the history of chlorosulfolipids from the early stages of their isolation, relevant structural elucidation techniques, appropriate biosynthetic discoveries, and their biological relevance to a thorough investigation of the total syntheses completed to date. These compounds demonstrate a range of biological activities and have …
Scanning Probe Investigations Of Nanopatterned And Thermo-Responsive Polypeptoids And The Design Of A Sample Stage For Force Modulation Microscopy, Lu Lu
LSU Doctoral Dissertations
Protocols for patterning nanostructures of polymers were developed to enable scanning probe microscopy (SPM) studies of surface properties at the molecular level. A chemically selective surface for patterning polymers was generated by combining particle lithography with organosilane immersion. Poly(N-allyl glycine), a biocompatible and backbone degradable polypeptoid, was grown on Si(111) at confined amine sites using surface-initiated polymerization (also known as the “graft from” approach). A thermo-responsive random copolypeptoid, poly[(N-ethyl glycine)32-r-(N-butyl glycine17)], was pre-synthesized and attached onto a patterned organosilane surface using a thiol-ene click reaction (“graft to” approach). The phase transitions of the copolypeptoid nanostructures in an aqueous environment was …
Method Development For The Assignment Of Nmr Peaks And The Determination Of Quaternary Protein Structure Using Reductive Methylation, Pamlea Nicole Brady
Method Development For The Assignment Of Nmr Peaks And The Determination Of Quaternary Protein Structure Using Reductive Methylation, Pamlea Nicole Brady
LSU Doctoral Dissertations
The work described herein is centered on reductive methylation, a chemical modification reaction, which allows for the introduction of methyl groups at the primary amines of the lysine side chain and at the N-terminus. The resulting methyl groups are effective probes for the study of protein structure and dynamics using nuclear magnetic resonance spectroscopy (NMR). Described herein is work conducted on the development of tools for the study of protein structure using reductive methylation, highlighting options for addressing limitations of the labeling method encountered by its practical use. Chapter 1 serves as a brief introduction to protein structure and the …
Investigating The Photorecombination Dynamics In Molecular High-Harmonic Spectra, Benjamin Parker Wilson
Investigating The Photorecombination Dynamics In Molecular High-Harmonic Spectra, Benjamin Parker Wilson
LSU Doctoral Dissertations
The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This work specifically aims to establish parameters for which the comparison is applicable and the macroscopic complications inherent in HHG do not interfere with the extraction of dynamic information. The first part of this work established the macroscopic experimental apparatus necessary for consistent spectroscopic observation. It is shown that using a gas jet that is an order of magnitude shorter than the Rayleigh length of the driving laser results in more consistent harmonic spatial profiles and …
Boron Functionalization Of Bodipy Dyes, And Their Evaluation As Bioimaging Agents, Alex Long Nguyen
Boron Functionalization Of Bodipy Dyes, And Their Evaluation As Bioimaging Agents, Alex Long Nguyen
LSU Doctoral Dissertations
BODIPY, also known as “porphyrin’s little sister,” belongs to a class of fluorescent dyes. It contains a dipyrromethene π-system with a disubstituted boron atom. The basic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) is known for its numerous useful applications in the fields of biology and materials. Modification of this well-known fluorophore has been shown to change its photophysical and chemical properties. There has been great interest in the modification at the boron center in recent years for synthesizing new dyads and cascade-type dyes. This work focuses on functionalization at the boron center with carbon and oxygen nucleophiles for further investigation as bioimaging agents. Chapter …
I. Synthesis Of Ascarosides For Biological Evaluation And Ii. Development Of Visible Light-Promoted Selenofunctionalization And Grafting Of Aryl Iodides, Elizabeth Susan Conner Balapitiya
I. Synthesis Of Ascarosides For Biological Evaluation And Ii. Development Of Visible Light-Promoted Selenofunctionalization And Grafting Of Aryl Iodides, Elizabeth Susan Conner Balapitiya
LSU Doctoral Dissertations
This dissertation focuses on analog synthesis for biological evaluation and visible light promoted method development. Chapter 1 centers upon the synthesis of Caenorhabditis elegans dauer pheromone analogs. C. elegans is a nematode which, in times of environmental stress, enters a dauer stage. Two highly conserved pathways, which play important roles in some diseases in higher organisms, monitor dauer formation: TGF-β and IGF-1. Dauer formation is triggered by the nematode’s chemosensation of the dauer pheromone, consisting of a group of previously-isolated ascarosides. These compounds differ in chain length, saturation, terminal functionality of side chain, ω vs. ω-1 oxygenation and presence of …
Synergistic Properties-Driven Synthesis Of Aluminides, Antiomonides, And Bioceramics, Pilanda Watkins-Curry
Synergistic Properties-Driven Synthesis Of Aluminides, Antiomonides, And Bioceramics, Pilanda Watkins-Curry
LSU Doctoral Dissertations
The synthesis, characterization, and properties of selected intermetallics and ceramic materials are presented in this dissertation. In our quest to grow single crystal intermetallics from the metal flux technique, new strategies were employed to avoid thermodynamically stable phases and to ensure sample homogeneity of the crystalline product for structure elucidation and accurate measurements of their magnetic and electrical properties. The relationship between the complex crystal structures and magnetic properties are reported for LnCo2Al8 (Ln = La-Nd, Sm, Yb), CeCo2-xMnxAl8 (0 < x < 1), and Pr2Fe4-xCoxSb5 (1 ≤ x < 3). The discovery of magnetic frustration in LnCo2Al8 (Ln = Ce, Nd) and complex magnetic ordering coupled with large positive magnetoresistance of up to 150% and 60% at 200 K with relatively low field of H = 1 T in Pr2Fe4-xCoxSb5 (x ≈ 2 and 2.5) is also reported. The demand of new inorganic solid materials as scaffolds for the engineering of bone tissue has led to the synthesis of calcium magnesium silicates such as, diopside (CaMgSi2O6), akermanite (Ca2MgSi2O7), monticellite (CaMgSiO4), and merwinite (Ca3Mg(SiO4)2)) for studying dimensionality and mechanical properties. This dissertation highlights the synergism of solid state chemistry at the interface of condensed matter physics and biological engineering. The discovery of compounds with tunable magnetic, electrical, and mechanical properties will be described herein.
I. Synthesis Of Ascarosides For Chemical Biology Studies In Caenorhabditis Elegans, Ii. A Photochemical Approach To Delavayine, And Iii. Remote Hydroxylation By Radical Translocation And Polar Crossover, Kyle Allen Hollister
LSU Doctoral Dissertations
The foci of this dissertation are the synthesis of analogs for chemical biology studies, synthetic chemistry method development (with an emphasis on photochemistry), and the application of these methods toward total synthesis. Chapter 1 outlines the synthesis of an array of pheromone analogs that are derivatives of the dideoxy sugar ascarylose. Referred to as ascarosides, such compounds have recently been shown to influence important biological processes in the model organism Caenorhabditis elegans. C. elegans secretes ascarosides into its environment, where the compounds then act as signaling molecules by providing information on factors like population density. Chapter 2 describes the biological …