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Full-Text Articles in Physical Sciences and Mathematics

The Forensic Analysis Of Triacetone Triperoxide (Tatp) Precursors And Synthetic By-Products, Kimberly Painter Jan 2009

The Forensic Analysis Of Triacetone Triperoxide (Tatp) Precursors And Synthetic By-Products, Kimberly Painter

Electronic Theses and Dissertations

Triacetone Triperoxide (TATP) is a primary high explosive that can be synthesized using commercially available starting materials and has grown in use among terrorists over the past several years. Additives present in the precursors were investigated to see if they carry through the TATP synthesis and can be detected in the final product potentially aiding in the identification of the source. Additives identified in the acetones were also identified in pre-blast and in some post-blast samples. However, these additives are present in trace quantities relative to the TATP, which coupled with the volatility and short lifetimes of some of the …


Room Temperature Synthesis And Systematic Characterization Of Ultra-Small Ceria Nanoparticles, Chetak Patel Jan 2009

Room Temperature Synthesis And Systematic Characterization Of Ultra-Small Ceria Nanoparticles, Chetak Patel

Electronic Theses and Dissertations

Cerium oxide (ceria, CeOâ‚‚) is a rare earth oxide that has attracted wide-spread research interest because of its unique properties such as high mechanical strength, oxygen ion conductivity, oxygen storage capacity and autocatalytic property. In recent years, researchers have discovered that ceria nanoparticles (NPs) are capable of protecting cells from free radical induced damage. Interestingly, it was found that nanometer size (~ 5 nm) ceria can scavenge free radicals quite efficiently, thus acting as an anti-oxidant. This phenomenon has been explained based on the autocatalytic property of ceria NPs. Several methods have been developed for the synthesis of ceria NPs …


A Preliminary Study Of A Non-Invasive Glucose Sensor Based On A Mercury Sensor, Erin Wood Jan 2009

A Preliminary Study Of A Non-Invasive Glucose Sensor Based On A Mercury Sensor, Erin Wood

Electronic Theses and Dissertations

Diabetes mellitus is a potentially lethal disease that affects 7.6 percent of American people. In the US, it is recognized as the 6th leading cause of death. Failure to control blood glucose levels (BGL) in patients with either type of diabetes can lead to other serious complications as well, such as loss of limb, blindness and other health problems. Controlling and monitoring the BGL in post-op and intensive care patients in the hospital is also vital to their health. Currently the most reliable method of monitoring BGL is through an invasive procedure which monitors the amount of glucose in blood …


Design, Synthesis, And Characterization Of Novel Hydrophilic Fluorene-Based Derivatives For Bioimaging Applications, Dao Nguyen Jan 2009

Design, Synthesis, And Characterization Of Novel Hydrophilic Fluorene-Based Derivatives For Bioimaging Applications, Dao Nguyen

Electronic Theses and Dissertations

In this work, hydrophilic fluorene-based derivatives that contain ethylene oxide substituents, have been synthesized and characterized for potential use as new fluorophores for bioimaging applications and for fluorescence sensing of heavy metals. Symmetrical and unsymmetrical fluorene derivatives based on structural types of acceptor-pi-acceptor, acceptor-pi-donor, and donor-pi-donor were characterized by TGA, UV-vis absorption, fluorescence emission, lifetime, anisotropy, and two-photon absorption (2PA) cross section. They were found to possess high thermal stability, high photostability, high fluorescence quantum yields, and generally large two-photon absorption cross sections, making them quite suitable for new probes in single-photon absorption and two-photon absorption fluorescence microscopy imaging. Novel …


Imaging And Spectroscopy Of Conducting Polymer-Fullerene Composite Materials, Daeri Tenery Jan 2009

Imaging And Spectroscopy Of Conducting Polymer-Fullerene Composite Materials, Daeri Tenery

Electronic Theses and Dissertations

Since the development and optical study of conjugated (conducting) polymers it has become apparent that chain conformation and aggregation at the molecular scale result in complex heterogeneous nanostructured bulk materials for which a detailed insight into morphological, spectroscopic as well as optoelectronic properties and mechanisms is overwhelmingly difficult to obtain. Nanoparticles composed of the conjugated polymer poly (MEH-PPV) and nanocomposite nanoparticles consisting of MEH-PPV doped with 1-(3-methoxycarbonylpropyl)-1-phenyl-C61 (PCBM) were prepared as model systems to study these materials at the length scale of one to a few domains. The MEH-PPV and PCBM doped nanoparticles were analyzed by single imaging/particle spectroscopy (SPS) …


Application Of Alkylsilane Self-Assembled Monolayers For Cell Patterning And Development Of Biolocial Microelectromechanical Systems, Kerry Wilson Jan 2009

Application Of Alkylsilane Self-Assembled Monolayers For Cell Patterning And Development Of Biolocial Microelectromechanical Systems, Kerry Wilson

Electronic Theses and Dissertations

Advances in microfabrication and surface chemistry techniques have provided a new paradigm for the creation of in vitro systems for studying problems in biology and medicine in ways that were previously not practical. The ability to create devices with micro- to nano-scale dimensions provides the opportunity to non-invasively interrogate and monitor biological cells and tissue in large arrays and in a high-throughput manner. These systems hold the potential to, in time, revolutionize the way problems in biology and medicine are studied in the form of point-of-care devices, lab-on-chip devices, and biological microelectromechanical systems (BioMEMS). With new in vitro models, it …


Synthesis Of Novel Fluorene-Based Two-Photon Absorbing Molecules And Their Applications In Optical Data Storage, Microfabricatio, Ciceron Yanez Jan 2009

Synthesis Of Novel Fluorene-Based Two-Photon Absorbing Molecules And Their Applications In Optical Data Storage, Microfabricatio, Ciceron Yanez

Electronic Theses and Dissertations

Two-photon absorption (2PA) has been used for a number of scientific and technological applications, exploiting the fact that the 2PA probability is directly proportional to the square of the incident light intensity (while one-photon absorption bears a linear relation to the incident light intensity). This intrinsic property of 2PA leads to 3D spatial localization, important in fields such as optical data storage, fluorescence microscopy, and 3D microfabrication. The spatial confinement that 2PA enables has been used to induce photochemical and photophysical events in increasingly smaller volumes and allowed nonlinear, 2PA-based, technologies to reach sub-diffraction limit resolutions. The primary focus of …


Synthesis Of Biocompatible Antioixidant Polymer Coated Cerium Oxide Nanoparticles, Its Oxidase Like Behavior And Cellular Uptake, Atul Asati Jan 2009

Synthesis Of Biocompatible Antioixidant Polymer Coated Cerium Oxide Nanoparticles, Its Oxidase Like Behavior And Cellular Uptake, Atul Asati

Electronic Theses and Dissertations

Cerium oxide nanoparticles have been widely used for various applications such as catalytic converters for automobile exhaust, ultraviolet absorber, and electrolyte in fuel cells. Most recently, cerium oxide nanoparticles (nanoceria) have been employed as potent free-radical scavengers with neuroprotective, radioprotective, and anti-inflammatory properties. These properties of cerium oxide nanoparticles can open new vistas in medicine and biotechnology. The present study utilizes the water-based-wet-chemical method to synthesize biocompatible,stable and highly monodisperse polymer coated cerium oxide nanoparticles. Polymer coated cerium oxide nanoparticles possess all the characteristics of the uncoated cerium oxide nanoparticles. These nanoparticles were found to be effective as pH-dependent antioxidant …


Development Of Novel Dart Tofms Analytical Techniques For The Identification Of Organic Contamination On Spaceflight-Related Substrates And Aqueous Media, Kathleen Loftin Jan 2009

Development Of Novel Dart Tofms Analytical Techniques For The Identification Of Organic Contamination On Spaceflight-Related Substrates And Aqueous Media, Kathleen Loftin

Electronic Theses and Dissertations

Organic contamination on spaceflight hardware is an ongoing concern for spaceflight safety. In addition, for the goal of analyzing for possible evidence of extra-terrestrial life, it is necessary to consider the presence of terrestrial contamination. This paper will introduce and evaluate a new method using a direct analysis real time (DART) ionization source paired with a high resolution time of flight mass spectrometer (TOFMS) for the determination of organic contamination involved in spaceflight hardware and ground support materials. This novel analytical technique has significant advantages over current methodologies. Materials analyzed in this study were historically considered as probable contaminants in …


Gold Nanoparticles: Synthesis, Property Study And Applcications For Biomolecular Detection And Photothermal Therapy, Xiong Liu Jan 2009

Gold Nanoparticles: Synthesis, Property Study And Applcications For Biomolecular Detection And Photothermal Therapy, Xiong Liu

Electronic Theses and Dissertations

This dissertation presents a systematic study on gold nanoparticles: from their chemical synthesis, modification of surface functionalities, optical properties studies with emphasis on the absorption and scattering properties, to applications of gold nanoparticles in biomolecular detection, imaging and photothermal therapy. In chapter 2, we studied the kinetics of gold nanoparticle growth under Brust-Shiffrin reaction conditions. In chapter 3, we further examined the reaction mechanism and growth kinetics of gold nanoparticles using oleylamine as both a reducing reagent and particle growth passivation ligand. From these two projects, important understanding was revealed on gold nanoparticle formation and growth mechanism. Chapter 4 describes …


Room Temperature Fluorescence Spectroscopy As A Tool For The Forensic Trace Analysis Of Textile Fibers, Matthew Rex Jan 2009

Room Temperature Fluorescence Spectroscopy As A Tool For The Forensic Trace Analysis Of Textile Fibers, Matthew Rex

Electronic Theses and Dissertations

Trace textile fiber evidence is found at numerous crime scenes and plays an important role in linking a suspect to the respective scene. Several methods currently exist for the analysis of trace fiber evidence. Microscopy provides information regarding the fibers material, color and weave. For more detailed chemical analysis chromatographic methods are employed and for discrimination between dyes, liquid chromatography coupled with mass spectrometry (LC-MS) is currently the method providing the most discrimination. These methods have primarily focused on the dyes used to color the fibers and have not investigated other components that can potentially discriminate among fibers. This dissertation …


The Biochemical Reactions Of Dry State Dna, April Marrone Jan 2009

The Biochemical Reactions Of Dry State Dna, April Marrone

Electronic Theses and Dissertations

The biochemistry of dry state DNA is of interest to the fields of forensics, ancient DNA, and DNA storage. The exact chemical nature of the degradation of the DNA molecule in the dry state has not been studied prior. If determined what chemical changes the DNA molecule undergoes, to what degree and in what time frame then protocols can be implemented to bypass the impact of this damage or to repair it when necessary. It is suspected that similar reactions occur to the dry state DNA molecule as does to the hydrated molecule. It cannot be assumed, however that these …