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Lee, Ching Ching. "Utilising phase transfer agents to enhance rapid detection of chemical warfare nerve agents." Thesis, Lee, Ching Ching (2021) Utilising phase transfer agents to enhance rapid detection of chemical warfare nerve agents. Masters by Research thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/64514/.
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Methylphosphonic acid (MPA) is the final degradant of many chemical warfare nerve agents (CWAs). Its detection in environmental and biological samples is a potential indicator of nerve agent use. Due to its high polarity and low volatility, analysis using gas chromatography-mass spectrometry (GC-MS) requires the derivatisation of MPA into a more volatile and less polar species. Currently, to derivatise MPA, it is typically necessary to perform the time-consuming and error-inducing water removal process prior to derivatisation. Therefore, it is of paramount importance to develop alternate rapid derivatisation methods for MPA to reduce the turnaround time for its detection and analysis.
Pilot studies undertaken at Murdoch University found that MPA could be derivatised without the removal of water via tert-butyldimethylsilylation using a two-phase aqueous/organic system. Although the reaction could be completed within 30 minutes, the derivatisation efficiency was found to be low. Therefore, this study aimed to improve the derivatisation efficiency of this method using phase transfer agents. Four phase transfer agents were tested (tetramethylammonium bromide, tetrabutylammonium bromide, tetrahexylammonium bromide and tetraoctylammonium bromide). Tetraoctylammonium bromide was discovered to significantly improve the efficiency of two-phase derivatisation in only half the time. Amount of phase transfer agent, reaction temperature and time were also optimised. Optimal derivatisation occurred in 15 minutes at 60 °C using 10 mol% of phase transfer agent. Initial attempts to quantify derivatisation efficiency using 31P-NMR to determine the concentration of MPA remaining in aqueous phase were unsuccessful. However, quantification of the derivative using GC-MS, revealed the efficiency of this two-phase phase transfer agent method was 30.25 ± 1.78%, a tenfold increase compared to the previous method. The qualitative detection limit of this phase transfer agent method was 1 ppm, which was yet another significant improvement from the initial 1000 ppm. Attempts were also made to isolate pure bis[tert-butyl(dimethyl)silyl] ester of MPA for the first time, but were terminated due to time constraint. However, high performance liquid chromatography (HPLC) separation results suggested that isolation of the derivative is possible.
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Beck, Jeremy M. "Organophosphorus nerve agent chemistry; interactions of chemical warfare agents and their therapeutics with acetylcholinesterase." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313416337.
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Jeune, Gareth Huw. "An investigation into hydroxyl radical processes for the destruction of chemical warfare agents." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360079.
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Zhang, Yaofang. "Elemental Detection with ICPMS - Implications from Warfare Agents to Metallomics." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1335463155.
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Kern, Rory James. "Enzyme-based detoxification of organophosphorus neurotoxic pesticides and chemical warfare agents." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2118.
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Bacena, Dulay Samuel. "Development of electrochemical biosensors for the detection of biological warfare agents." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/279295.
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En aquesta tesi, s’ha desenvolupat un sensitiu bio-sensor electroquímic, amb capacitat de multiplexió, simple, de baix cost i portable, per a la detecció ràpida i fiable d’agents de guerra biològica en diferents situacions com la seguretat nacional, operacions militars i seguretat en instal•lacions dels transports públics. En el desenvolupament de l’immuno-sensor es van explorar diferents superfícies químiques, utilitzant fragments d’anticossos o anticossos sencers per a la detecció de cèl•lules bacterianes. També es va explorar la detecció d’anticossos d’anti-Francisella tularensis en mostres de sèrum animal infectades amb tularemia. Els resultats van mostrar un bon grau de correlació en ésser comparats amb els obtinguts mitjançant mètodes ELISA. En el desenvolupament del bio-sensor d’ADN, es va dur a terme la detecció simultània de vuit (8) espècies virulentes, emprant un conjunt de sensors, amb diferents dissenys de sondes. El conjunt de bio-sensors i l’immuno-sensor van ser integrats amb micro-fluids localitzats en un dispositiu de testeig. Utilitzant un mètode de nano-plantilles (diferents fases de surfactant octaethylene glycol monohexadecyl ether) per a una millor distribució de les sondes, es va aconseguir millorar la sensibilitat i el límit inferior de detecció del bio-sensor d’ADN, millorant l’eficiència d’hibridació. Les superfícies modificades d’elèctrode d’or van ser avaluades mitjançant fluorescència i força atòmica microscòpica i electroquímica. En general, aquest treball constitueix una completa visió del desenvolupament de bio-sensors electroquímics per a la detecció de cèl•lules bacterianes de F. tularensis, anticossos anti-F. Tularensis, així com d’un conjunt de bio-sensors d’ADN multiplexats, altament sensitius i selectius per a la detecció de productes RCP.n esta tesis, se desarrolló un sensitivo bio-sensor electroquímico, con capacidad de multiplexión, simple, de bajo coste y portable, para la detección rápida y fiable de agentes de guerra biológica en diferentes situaciones como la seguridad nacional, operaciones militares y seguridad en instalaciones de los transportes públicos. En el desarrollo del inmuno-sensor, se exploraron diferentes superficies químicas usando fragmentos de anticuerpos o anticuerpos enteros para la detección de células bacterianas. También se exploró la detección de anticuerpos de anti-Francisella tularensis en muestras de suero animal infectadas con tularemia. Los resultados mostraron un buen grado de correlación al ser comparados con los obtenidos mediante métodos ELISA. En el desarrollo del bio-sensor de ADN se llevó a cabo la detección simultánea de ocho (8) especies virulentas utilizando un conjunto de sensores, con diferentes diseños de sondas. El conjunto de bio-sensores i el inmuno-sensor fueron integrados con micro-fluidos localizados en un dispositivo de testeo. Usando un método de nano-plantillas (diferentes fases de surfactante octaethylene glycol monohexadecyl ether) para una mejor distribución de las sondas, se consiguió mejorar la sensibilidad y el límite inferior de detección del bio-sensor de ADN, mejorando la eficiencia de hibridación. Las superficies modificadas de electrodo de oro fueron evaluadas mediante fluorescencia y fuerza atómica microscópica y electroquímica. En general, este trabajo constituye una completa visión del desarrollo de bio-sensores electroquímicos para la detección de células bacterianas de F. tularensis, anticuerpos anti-F. Tularensis, así como de un conjunto de bio-sensores de ADN multiplexados altamente sensitivos y selectivos para la detección de productos RCP.
In this thesis, a simple, low cost, portable, multiplexing capable and sensitive electrochemical biosensor was developed for rapid and reliable detection of biowarfare agents for different situations like homeland security, military operations, public transportation securities such as airports, metro and railway stations. In the development of immunosensor, different surface chemistry using antibody fragments or whole antibodies were explored for bacterial cells detection. The detection of anti-Francisella tularensis antibodies in animal serum samples known to be infected with tularemia was also explored. The results obtained were compared to that obtained using ELISA methods with a good degree of correlation. In the development of multiplexed DNA biosensor, simultaneous detection of eight (8) virulent species using a sensor array was developed using different designs of capture probes. The developed multiplexed biosensor array and immunosensor for detecting bacterial cells were integrated with microfluidics housed in a tester set-up device. The search to improve sensitivity and lower limit of detection of a DNA biosensor was achieved using a nanotemplating method for a better probe distribution enhancing hybridisation efficiency. Different phases of the surfactant octaethylene glycol monohexadecyl ether were used as templates. Fluorescence and atomic force microscopy as well as electrochemistry were used to evaluate the modified surfaces of gold electrode. Overall, this work constitutes a complete overview of the development of electrochemical biosensors for the detection of bacterial cells of F. tularensis, anti-F. tularensis antibodies as well a highly sensitive and selective multiplexed DNA biosensor array for the detection of PCR products.
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Swartz, Jeffrey R. "Biological toxin warfare : threat, proliferation, and the effects of neutron energy on BTW agents /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://edocs.nps.edu/npspubs/scholarly/theses/1995/Sep/95Sep_Swartz.pdf.
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Thesis (M.S. in Systems Technology (Scientific and Technical Intelligence)) Naval Postgraduate School, September 1995."September 1995." Thesis advisor(s): K.E. Woehler, Peter Lavoy. Bibliography: p. 73-74. Also available online.
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Price, Sarah Ellen. "Ion mobility and mass spectrometric investigations of organophosphates related to chemical warfare agents and pesticides." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1027/.
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A commercial Ion Mobility Spectrometer that is designed to detect Chemical Warfare Agents (CWAs), is modified by the addition of a second ion gate, and connected to a commercial Ion Trap Mass Spectrometer (ITMS). The addition of the second gate allows selection of individual ion mobility peaks for m/z analysis in the ITMS. This was demonstrated with the organophosphorus ester ions (CWA nerve gas simulants). The ITMS was used to perform isolation and fragmentation of the CWA simulants ions produced in the IMS. For the organophosphates dimethyl methylphosphonate, diethyl methylphosphonate and diisopropyl methylphosphonate, two ion mobility peaks were observed, which are shown to be the ammoniated monomer and ammoniated dimer ions. Using an ElectroSpray Ionisation (ESI) - ITMS, the fragmentation pathway of dimethyl ethylphosphonate (DMEP) is investigated. The isotopomers of DMEP have unusual fragmentations, and density functional theory calculations are used to aid in the interpretation of the mechanisms involved in these fragmentations. Of note, it is shown that entropy must be taken into consideration, and hence the free energy of the final transition involved in the mechanism, so that the true rate-limiting steps can be determined. Preliminary fragmentations using ESI-ITMS of eighteen other organophosphorus esters have been undertaken. These give an insight as to which fragmentations will require further investigations involving Density Functional Theory (DFT) calculations and deuterated isotopomers to fully understand the mechanisms involved.
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Singh, Ashish C. "Improving the survivability of agents in a first-person shooter urban combat simulation by incorporating military skills." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/a_singh_111607.pdf.
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Chapleski, Jr Robert Charles. "Computational Investigations at the Gas-Surface Interface: Organic Surface Oxidation and Hydrolysis of Chemical Warfare Agents and Simulants." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77514.
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Motivated by recent experiments in gas-surface chemistry, we report our results from computational investigations of heterogeneous systems relevant to atmospheric chemistry and protection against chemical weapons. To elucidate findings of ultra-high vacuum experiments that probe the oxidation of carbon-carbon double bonds on model surfaces, we used electronic structure and QM/MM methods to study the reaction of ozone with C60-fullerene and the products of nitrate addition to a vinyl-terminated self-assembled monolayer. In the first system, we followed a reaction pathway beginning with primary ozonide formation through the formation of stable products. Theoretical vibrational spectra were used to identify a ketene product in prior experimental work. Next, through the construction of a multilayer model for the initial addition product of a nitrate radical to a chain embedded within a self-assembled monolayer, we report theoretical spectra that are consistent with experimental results. We then examined the fundamentals of the hydrolysis mechanism for nerve agents by a catalyst of interest in the development of filtration materials for chemical-warfare-agent defense. By following the gas-surface reaction pathway of the nerve agent Sarin on the Lindqvist polyoxoniobate Cs8Nb6O19, we determined that the rate-limiting step is the transfer of a proton from an adsorbed water molecule to the niobate surface, concomitant with the nucleophilic addition of the nascent hydroxide to the phosphorus atom in Sarin. Our results support a general base hydrolysis mechanism, though high product-adsorption energies suggest that thermal treatment of the system is required to fully regenerate the catalyst. We report similar mechanisms for the simulants dimethyl methylphosphonate and dimethyl chlorophosphate, though the latter may serve as a better simulant in studies of this type. Finally, an investigation of Sarin hydrolysis with solvated Cs8Nb6O19 shows an increase in the rate-limiting barrier relative to the gas-surface system, revealing the role of Cs counterions in the reaction. Then, we further increased explicit solvation to model the homogeneous solution-phase reaction, finding a different mechanism in which a water molecule adds to phosphorus in the rate-limiting step and protonation of the niobate surface occurs in a subsequent barrierless step. By examining the rate-limiting barrier for protonation, we suggest that specific base hydrolysis is also likely in the homogeneous system.Ph. D.
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Reeves, Tony Elvern. "Rational design of organophosphorus hydrolase for the degradation and detection of neurotoxic pesticides and chemical warfare agents." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/5800.
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It is critical to consider the balance between the catalytic capabilities of an enzyme and the inherent structural stability of the protein when developing enzymes for specific applications. Rational site directed mutagenesis has been used to explore the role of residues 254 and 257 in the global stability and catalytic specificities of organophosphorus hydrolase (OPH, EC 3.1.8.1). Substitution of residues H254 and H257, which are located near the active site, had a marked effect on both the global stability and substrate specificity of the enzyme. For example, the for the double mutation CoTGÃÂ2+ H254R H257L (RL) enzyme variant was 19.6 kcal/mol, 5.7 kcal/mol less than that of the wild type enzyme. At the same time, the altered enzyme was catalytically more effective against VX and VR (Russian VX), as compared to the wild type enzyme. Limited proteolysis verified the importance of residues 254 and 257 for functional stability, evidenced by enhanced resistance to irreversible unfolding associated with thermal denaturation. It has been possible to construct third generation OPH variants, which are more stable than the wild type enzyme, with a 10 ðC increase in the apparent melting temperature (TM app), yet retained desirable catalytic properties. It appeared that aromatic stacking and cation-àinteractions involving near active site residues not only affected activity but significantly contributed to the chemical and thermal stability of OPH. Rational design was used to develop an enzyme with an optimized orientation on a catalytically active biosensor surface. In these studies, lysine side chains located on the surface of OPH were used to create attachment sites to a surface plasmon resonance sensor resulting in an ensemble of enzyme orientations. Some of these orientations could be functionally restrictive if the active site is oriented toward the sensor surface. Substitution of a lysine near the active site resulted in 20% more activity with 53% less enzyme immobilized, thus increasing the specific activity of the decorated surface 2.5 fold.
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Wilmsmeyer, Amanda Rose. "Ultrahigh Vacuum Studies of the Fundamental Interactions of Chemical Warfare Agents and Their Simulants with Amorphous Silica." Diss., Virginia Polytechnic Institute and State University, 2012. http://hdl.handle.net/10919/54366.
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Developing a fundamental understanding of the interactions of chemical warfare agents (CWAs) with surfaces is essential for the rational design of new sorbents, sensors, and decontamination strategies. The interactions of chemical warfare agent simulants, molecules which retain many of the same chemical or physical properties of the agent without the toxic effects, with amorphous silica were conducted to investigate how small changes in chemical structure affect the overall chemistry. Experiments investigating the surface chemistry of two classes of CWAs, nerve and blister agents, were performed in ultrahigh vacuum to provide a well-characterized system in the absence of background gases. Transmission infrared spectroscopy and temperature-programmed desorption techniques were used to learn about the adsorption mechanism and to measure the activation energy for desorption for each of the simulant studied. In the organophosphate series, the simulants diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), trimethyl phosphate (TMP), dimethyl chlorophosphate (DMCP), and methyl dichlorophosphate (MDCP) were all observed to interact with the silica surface through the formation of a hydrogen bond between the phosphoryl oxygen of the simulant and an isolated hydroxyl group on the surface. In the limit of zero coverage, and after defect effects were excluded, the activation energies for desorption were measured to be 57.9 ± 1, 54.5 ± 0.3, 52.4 ± 0.6, 48.4 ± 1, and 43.0 ± 0.8 kJ/mol for DIMP. DMMP, TMP, DMCP, and MDCP respectively. The adsorption strength was linearly correlated to the magnitude of the frequency shift of the ν(SiO-H) mode upon simulant adsorption. The interaction strength was also linearly correlated to the calculated negative charge on the phosphoryl oxygen, which is affected by the combined inductive effects of the simulants’ different substituents. From the structure-function relationship provided by the simulant studies, the CWA, Sarin is predicted to adsorb to isolated hydroxyl groups of the silica surface via the phosphoryl oxygen with a strength of 53 kJ/mol. The interactions of two common mustard simulants, 2-chloroethyl ethyl sulfide (2-CEES) and methyl salicylate (MeS), with amorphous silica were also studied. 2-CEES was observed to adsorb to form two different types of hydrogen bonds with isolated hydroxyl groups, one via the S moiety and another via the Cl moiety. The desorption energy depends strongly on the simulant coverage, suggesting that each 2-CEES adsorbate forms two hydrogen bonds. MeS interacts with the surface via a single hydrogen bond through either its hydroxyl or carbonyl functionality. While the simulant work has allowed us to make predictions agent-surface interactions, actual experiments with the live agents need to be conducted to fully understand this chemistry. To this end, a new surface science instrument specifically designed for agent-surface experiments has been developed, constructed, and tested. The instrument, located at Edgewood Chemical Biological Center, now makes it possible to make direct comparisons between simulants and agents that will aid in choosing which simulants best model live agent chemistry for a given system. These fundamental studies will also contribute to the development of new agent detection and decontamination strategies.Ph. D.
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Soares, Carla Vieira. "Computational evaluation of MOFs for their adsorption and catalytic degradation performances with respect to chemical warfare agents." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTS015.
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Cette thèse vise à effectuer un criblage computationnel d'une grande série de structures métal-organiques (MOFs) contenant du Zr ou du Ti afin de prédire leurs performances vis-à-vis l'adsorption et dégradation des agents chimiques de guerre (ACGs). Cette étude inclut des agents neurotoxiques (Sarin et soman), agents vésicants (gaz moutarde) ainsi que leurs simulants, à savoir, le diméthyl méthylphosphonate, le diisopropyl phosphorofluoridate, le pinacolyl méthylphosphonate et le 2-chloroéthyl éthyl sulfure. Des calculs basés sur la Théorie de la Fonctionnelle de la Densité (DFT) ont été couplés à des simulations de Monte Carlo pour évaluer la capacité adsorptive, l'énergie et les sites d'adsorption préférentiels pour chaque paire MOF/ACG considérée. Ensuite, ces données ont été rationalisées afin d'établir des relations structure-propriété d'adsorption en prenant en compte des paramètres géométriques et électroniques caractéristiques des MOF, des ACGs ainsi que de leurs interactions croisées. Postérieurement, des calculs DFT ont été effectués afin d’élucider les mécanismes de dégradation des ACG et de leurs simulants sur les MOFs en analysant les principaux états intermédiaires de leurs réactions de dégradation et les énergies d'activation résultantes. Finalement, les mécanismes d'hydrolyse d'une série de MOFs à base de Ti et Zr ont été explorés par la voie des calculs DFT dans le but d'identifier les paramètres clés qui contrôlent leur stabilité sous humidité. Ces études computationnelles doivent ouvrir la voie à des nouvelles MOF avec des performances de capture/dégradation améliorées qui pourraient être appliquées comme filtres de ACGsThe present PhD thesis aims to perform a computational evaluation of a large series of Metal Organic Frameworks (MOFs) containing Zr or Ti as the metal centers for their adsorption and degradation performances with respect to chemical warfare agents: nerve agents (Sarin and Soman), vesicant agents (Sulfur Mustard) as well as their simulants, Dimethyl methylphosphonate, Diisopropyl phosphorofluoridate, Pinacolyl methylphosphonate and 2-Chloroethyl ethyl sulfide. This was achieved by combining Density Functional Theory (DFT) calculation and Monte Carlo simulations to assess the adsorption uptake, the energetics and the preferential adsorption sites for each considered MOF/CWA pair. The rationalization of the so-generated database was further achieved in order to establish structure-adsorption property relationships with the consideration of geometric and electronic descriptors characterizing MOFs, CWAs as well as CWA/MOF interactions. As a further step, DFT calculations were performed to elucidate the degradation mechanisms for CWAs and their simulants on the Ti or Zr-MOFs analyzing the main states of the degradation reaction and the resulting activation energies. Finally, the hydrolysis mechanism of a series of Zr and Ti-MOFs was explored by means of DFT calculations with the objective to identify the key parameters that control their stability under humidity. This computational work is expected to pave the way towards refined MOFs with improved capture/degradation performances to be potentially applied as CWA filters
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Engells, Thomas E. "Biosecurity of select agents and toxins." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FEngells.pdf.
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Thesis (M.A. in Security Studies (Homeland Security and Defense))--Naval Postgraduate School, March 2005.Thesis Advisor(s): Maria Rasmussen. Includes bibliographical references (p. 65-71). Also available online.
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Subramaniam, Raja. "Simplified Routines for Sample Preparation and Analysis of Chemical Warfare Agent Degradation Products." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-54639.
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The thesis describes the development of new and improved methods for analyzing degradation markers from organophosphorus Chemical Warfare Agents (CWAs). Paper I and II describes an innovative and significantly improved method for the enrichment, derivatization (trimethysilylation) and GC-MS analysis of a broad range of organophosphorus CWAs degradation markers, namely the alkylphosphonic acids and a zwitterionic compound. That was achieved using solid phase disc extraction in combination with solid phase derivatization. The new method overcomes most limitations observed with existing techniques: it offers almost 100 % recoveries, requires no elution or evaporation steps, facilitates miniaturization of the solid sorbent and reagent, is compatible with in-vial derivatization, and minimizes the chromatographic background due to the use of a highly selective anion exchange sorbent disc. Paper III describes the development of new fluorinated diazomethane derivatization reagents and their evaluation for rapid and high sensitivity screening and identification of nerve agent degradation markers. The reagents are water-tolerant to some extent, which simplifies the derivatization step. The best reagent identified was 3,5-bis(trifluoromethyl)benzyl diazomethane, which outperformed the other reagent isomers tested and also the established commercial alternative, pentafluorobenzylbromide, allowing for the rapid (5 min) and direct derivatization of a 25 μL aqueous sample in acetonitrile. The spectra of the formed derivatives (high-energy collision induced fragmentation MS/MS) were used to construct a database (Paper IV) that proved to be superior in terms of match factor and probability compared to EI data gathered for trimethylsilyl derivatives. The study also focused on efforts towards achieving detailed structure information on the alkyl chains of the compounds in question using diagnostic ion interpretation. The final paper (paper V) describes the first rapid direct derivatization method for analyzing nerve agent metabolites in urine at trace levels. The method is based on the derivative from the paper III and the unambiguous identification was proven using a combination of low resolution and high resolution negative ion chemical ionization selected ion monitoring techniques. Novel results presented in these papers include: the first in-situ derivatization of alkylphosphonic acids on an SPE disc; the first direct derivatization of nerve agent markers in water and biomedical samples; the first high sensitivity GC-MS screening for these markers; and the first highly reproducible high-energy isomer specific CID MS/MS library. Overall, the results presented in this thesis represent significant contributions to the analysis of nerve agent degradation products.
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Ong, Kate K. Wei Yen. "Encapsulation of organophosphorus acid anhydrolase (OPAA) in nanostructured materials for the detection and decontamination of chemical warfare agents /." Philadelphia, Pa. : Drexel University, 2006. http://dspace.library.drexel.edu/handle/1860%20/895.
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Cioce, Christian R. "Computational Investigations of Potential Energy Function Development for Metal-Organic Framework Simulations, Metal Carbenes, and Chemical Warfare Agents." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5666.
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Metal-Organic Frameworks (MOFs) are three-dimensional porous nanomaterials with a variety of applications, including catalysis, gas storage and separation, and sustainable energy. Their potential as air filtration systems is of interest for designer carbon capture materials. The chemical constituents (i.e. organic ligands) can be functionalized to create rationally designed CO2 sequestration platforms, for example. Hardware and software alike at the bleeding edge of supercomputing are utilized for designing first principles-based molecular models for the simulation of gas sorption in these frameworks. The classical potentials developed herein are named PHAST -- Potentials with High Accuracy, Speed, and Transferability, and thus are designed via a "bottom-up" approach. Specifically, models for N2 and CH4 are constructed and presented.
Extensive verification and validation leads to insights and range of applicability. Through this experience, the PHAST models are improved upon further to be more applicable in heterogeneous environments. Given this, the models are applied to reproducing high level ab initio energies for gas sorption trajectories of helium atoms in a variety of rare-gas clusters, the geometries of which being representative of sorption-like environments commonly encountered in a porous nanomaterial. This work seeks to push forward the state of classical and first principles materials modeling.
Additionally, the characterization of a new type of tunable radical metal--carbene is presented. Here, a cobalt(II)--porphyrin complex, [Co(Por)], was investigated to understand its role as an effective catalyst in stereoselective cyclopropanation of a diazoacetate reagent. Density functional theory along with natural bond order analysis and charge decomposition analysis gave insight into the electronics of the catalytic intermediate. The bonding pattern unveiled a new class of radical metal--carbene complex, with a doublet cobalt into which a triplet carbene sigma donates, and subsequent back-bonding occurs into a pi* antibonding orbital. This is a different type of interaction not seen in the three existing classes of metal-carbene complexes, namely Fischer, Schrock, and Grubbs.
Finally, the virtual engineering of enhanced chemical warfare agent (CWA) detection systems is discussed. As part of a U.S. Department of Defense supported research project, in silico chemical modifications to a previously synthesized zinc-porphyrin, ZnCS1, were made to attempt to achieve preferential binding of the nerve agent sarin versus its simulant, DIMP (diisopropyl methylphosphonate). Upon modification, a combination of steric effects and induced hydrogen bonding allowed for the selective binding of sarin. The success of this work demonstrates the role that high performance computing can play in national security research, without the associated costs and high security required for experimentation.
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CENCIARELLI, ORLANDO. "Design and implementation of a biological warfare agents simulant spectral database for the automatic discrimination in unconventional scenarios." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2013. http://hdl.handle.net/2108/202293.
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The biological agents (BAs) can exist in the form of aerosolized bacteria, fungi or viruses, and they also may be spread by vectors and other routes like water and air supply (Cenciarelli et al., 2013; Kumar et al., 2013). Among the ways which allow the propagation of BAs, certainly air has a more rapid rate of diffusion; for this reason it is important to develop systems for remote sensing of airborne biological agents. Jonsson et al. (2005) successfully present a detection system for BAs based on spectral detection of ultraviolet (UV) laser induced fluorescence (LIF); spectral characterization was also illustrated for some simulants. The most common fluorophores found in bioaerosols are phenylalanine, tyrosine, tryptophan, nicotinamide adenine dinucleotide compounds (NADH), flavins and chlorophylls. Among these main fluorophores in bioaerosols, phenylalanine has little absorption above 270 nm, while chlorophylls adsorb around 430 nm. Excitation around 260-290 nm will mainly generate fluorescence emission from tyrosine, tryptophan, NADH, and flavin, while excitation around 350-410 nm will mainly produce fluorescence emission from NADH and flavin.
Although in the literature several studies regarding the ability to discriminate BAs through methods that exploit fluorescence excitation through ultraviolet radiation were presented, it appears to be essential to build and implement a database being able to return a response about the kind of BA detected according to a revealed fluorescence spectrum. Furthermore, in order to refine the experimental procedures, it appears essential to standardize the samples preparation methods. This represents the starting point for the creation of a pitched instrument.
This PhD research activity aims to design a biological warfare agents (BWA) spectral database using biological agents simulants (BWA-S) for the automatic discrimination in unconventional scenarios, i.e. by standardizing the experimental procedures (e.g. best samples preparation) and setting the better criteria for the algorithm analysis. The
PhD in Industrial Engineering - Final Dissertation - Orlando Cenciarelli
DESIGN AND IMPLEMENTATION OF A BIOLOGICAL WARFARE AGENTS SIMULANT SPECTRAL
DATABASE FOR THE AUTOMATIC DISCRIMINATION IN UNCONVENTIONAL SCENARIOS
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automatic classification system is based on a novel adaptative algorithm, named as Universal Multi-Event Locator (UMEL). UMEL is a universal technique based on Support Vector Regression (SVR), a version of Support Vector Machines (SVM) for function estimation (Carestia et al., 2014). SVR fits the training data discarding factors such as sampling rate or noise distribution. This technique computes a fitting function and, in addition, retrieves a list of points from the training set. These points become Support Vectors (SVs). For the first time, UMEL is used in this work to discriminate between fluorescence spectral signature of BWA-S.
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Edwards, Angela Celeste. "Probing the Hydrogen Bonding Interaction at the Gas-Surface Interface using Dispersion Corrected Density Functional Theory." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71784.
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he interactions of the chemical warfare agent sulfur mustard with amorphous silica were investigated using electronic structure calculations. In this thesis, the binding energies of sulfur mustard and mimic species used in the laboratory were calculated using density functional theory and fully ab initio calculations. The wB97XD and B97D functionals, which include functions to account for long-range dispersion interactions, were compared to experimental trends. The hydroxylated amorphous silica surface was approximated using a gas-phase silanol molecule and clusters containing a single hydroxyl moiety.
Recent temperature programmed desorption experiments performed in UHV concluded that sulfur mustard and its less toxic mimics undergo molecular adsorption to amorphous silica. Hydrogen bonding can occur between surface silanol groups and either the sulfur or chlorine atom of the adsorbates, and the calculations indicate that the binding energies for the two hydrogen bond acceptors are similar. The adsorption of sulfur mustard and its mimics on silica also exhibits the presence of significant van der Waals interactions between alkyl of the adsorbates and the surface. These interactions, in combination with the formation of a hydrogen bond between a surface silanol group and the Cl or S atoms of the adsorbates, provide remarkably large binding energies.Master of Science
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Daphney, Cedrick M. "The Fate and Transport of Chemical Warfare Agent Simulants in Complex Matrices." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_theses/13.
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Experiments to determine the fate and transport of the chemical warfare agent (CWA) simulants diisopropyl fluorophosphate (DIFP), O,S-diethyl methylphosphonothioate (OSDEMP), and 2-Chloroethyl ethyl sulfide (CEES) exposed to complex matrix systems are reported here. The aforementioned simulants were used in place of O-isopropyl methylphosphonofluoridate (GB), O-Ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX), and Bis (2-chloroethyl) sulfide (HD), respectively. At ambient temperature, simulant pH (2.63 to 12.01) and reaction time (1 minute to 24 hours) were found to have significant influence on the recovery of simulants from charcoal, plastic, and TAP (butyl rubber gloves) in aqueous media. Buffer systems used included, phosphate, acetate, borate, and disodium tetraborate. Organic extractions were carried out using a 90:10 (v/v) dichloromethane / 2-propanol solution. All extracts were analyzed with a gas chromatograph equipped with flame ionization and flame photometric detectors (GC-FID-FPD). The FPD was used to determine the amount of simulant recovery.
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Sharp, Conor Hays. "Fundamental Studies of the Uptake and Diffusion of Sulfur Mustard Simulants within Zirconium-based Metal-Organic Frameworks." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102928.
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The threat of chemical warfare agent (CWA) attacks has persisted into the 21st century due to the actions of terror groups and rogue states. Traditional filtration strategies for soldier protection rely on high surface area activated carbon, but these materials merely trap CWAs through weak physisorption. Metal-organic frameworks (MOFs) have emerged as promising materials to catalyze the degradation of CWAs into significantly less toxic byproducts. The precise synthetic control over the porosity, defect density, and chemical functionality of MOFs offer exciting potential of for use in CWA degradation as well as a wide variety of other applications. Developing a molecular-level understanding of gas-MOF interactions can allow for the rational design of MOFs optimized for CWA degradation. Our research investigated the fundamental interfacial interactions between CWA simulant vapors, specifically sulfur mustard (HD) simulants, and zirconium-based MOFs (Zr-MOFs). Utilizing a custom-built ultrahigh vacuum chamber with infrared spectroscopic and mass spectrometric capabilities, the adsorption mechanism, diffusion energetics, and diffusion kinetics of HD simulants were determined. For 2-chloroethyl ethyl sulfide (2-CEES), a widely used HD simulant, infrared spectroscopy revealed that adsorption within Zr-MOFs primarily proceeded through hydrogen bond formation between 2-CEES and the bridging hydroxyls on the secondary building unit of the MOFs. Through the study of 1-chloropentane and diethyl sulfide adsorption, we determined that 2-CEES forms hydrogen bonds through its chlorine atom likely due to geometric constraints within the MOF pore environment. Temperature-programmed desorption experiments aimed at determining desorption energetics reveal that 2-CEES remain adsorbed within the pores of the MOFs until high temperatures, but traditional methods of TPD analysis fail to accurately measure both the enthalpic and entropic interactions of 2-CEES desorption from a single adsorption site. Infrared spectroscopy was able to measure the diffusion of adsorbates within MOFs by tracking the rate of decrease in overall adsorbate concentrations at several temperatures. The results indicate that 2-CEES diffusion through the pores of the MOFs is a slow, activated process that is affected by the size of the pore windows and presence of hydrogen bonding sites. We speculate that diffusion is the rate limiting step in the desorption of HD simulants through Zr-MOFs at lower temperatures. Stochastic simulations were performed in an attempt to deconvolute TPD data in order to extract desorption parameters. Finally, a combination of vacuum-based and ambient-pressure spectroscopic techniques were employed to study the reaction between 2-CEES and an amine-functionalized MOF, UiO-66-NH2. Although the presence of water adsorbed within UiO 66 NH2 under ambient conditions may assist in the reactive adsorption of 2-CEES, the reaction proceeded under anhydrous conditions.Doctor of Philosophy
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Shah, Ekta J. "Effect of the Broad-Spectrum Caspase Inhibitor Q-VD-OPh on Neurodegeneration and Neuroinflammation of Sarin exposed mice." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1408977463.
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Spiandore, Marie. "Evaluation de la contamination et de la décontamination des cheveux après exposition à des agents chimiques toxiques." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4776.
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Comme l’a montré l’utilisation de sarin en Syrie en 2013, les agents chimiques de guerre restent une menace. L’exposition de populations est une situation d’urgence qui nécessite des moyens rapides et efficaces. La décontamination et le soin des personnes exposées restent une priorité. Les cheveux représentent une matrice couramment utilisée dans le domaine médico-légal. Dans ce travail, notre intérêt se porte sur la capacité du cheveu à capter et libérer des composés dans l’air, notamment l’ypérite, ainsi que sur l’efficacité de décontamination de cette matrice. Pour ce travail, nous avons utilisé deux composés aux propriétés physiques/chimiques proches de celles de l’ypérite : le salicylate de méthyle et le 2-chloroéthyl éthyl sulfure. Les deux similis ont été retenus par le cheveu avec une plus grande affinité pour le salicylate de méthyle. Nous avons observé une corrélation entre l’intensité d’exposition (influence de la dose et du temps) et la teneur en contaminants retrouvés sur les cheveux. Ces résultats montrent qu’il est possible d’utiliser le cheveu pour détecter une exposition individuelle. Après exposition, la teneur dans des cheveux laissés à désorber a été mesurée avec le salicylate de méthyle. Les résultats obtenus ont montré que les cheveux contaminés sont susceptibles de libérer les toxiques. Cela peut poser un problème sanitaire, qui implique donc que la décontamination des cheveux soit étudiée. Les protocoles de décontamination testés montrent une efficacité partielle (élimination de 40 à 80%). Ces résultats impliquent la nécessité d’optimiser les procédures actuelles ou de définir de nouveaux outils pour la décontamination du cheveu après expositionAs shown by sarin use in Syria (2013), chemical warfare agents remain a threat. Chemical exposure of populations is an emergency situation, where quick and efficient means are mandatory. Decontamination and care of the victims are a priority. Scalp hair is routinely used as a biological matrix in forensic sciences. In this thesis work, interest focuses on hair capacity to trap and release compounds from atmosphere, especially sulphur mustard, as well as decontamination of this matrix. For this work, two molecules with similar physical/chemical properties to sulphur mustard were used: methyl salicylate and 2-chloroethyl ethyl sulphide. Both simulants were trapped by scalp hair, with higher affinity towards methyl salicylate. We observed a correlation between exposure intensity (influence from dose and time) and simulant content recovered from hair analysis. Results suggest that hair can be used to assess individual contamination. After exposure, evolution of methyl salicylate hair content has been measured. Results pointed out that contaminated hair can thereafter release the simulants. This can lead to health issue, highlighting the fact that hair decontamination must be investigated. Tested decontamination protocols showed a partial efficacy (40-80% removal). Those results evidenced the need to optimise current procedures or define new tools for hair decontamination after chemical exposure
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Richardson, Douglas Dennis II. "Modern Advancements in Elemental Speciation: From Sample Introduction to Chemical Warefare Agent Detection." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250178457.
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Andrle, Marek. "Extrakční detoxikace citlivých komponent." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-233396.
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Solvent extraction is one of the methods available for the decontamination of sensitive equipments that are contaminated with chemical warfare agents. The efficiency of extraction method have been verified on the samples, (steel or rubber) that have been contaminated with drops of mustard gas. These samples have been inserted into the extraction flow cell through which solvent (ethoxynonafluorobutane - HFE-7200) flowed. The solvent was sampled in the time intervals. These samples of solvent were analysed for the concentration of mustard gas. Process of extraction was monitored for the three operational factors (the solvent flow rate, temperature and the ultrasound power) and for three different situations (dissolution of drops of mustard gas, mustard gas desorption from the structure of the sample and dissolve drops of mustard gas with the subsequent desorption from the sample). The development of the decontamination process in time was found to consist of two stages. In the first stage the rapid dissolution of the liquid part of mustard gas in a solvent and in the second phase was such as mustard desorption from the structure of the sample and this phase was considerably slower. Extraction is to accelerate increasing the value of the flow of the solvent, the temperature and the performance of the ultrasound. These operational fac-tors have a significant impact on the thickness of the laminar layer of solvent, the solvent replacement coefficient in a cell, diffusion parameters in the process, the viscosity, the solubility of mustard gas in a solvent and the maximum achievable concentration of mustard gas in the rubber sample. The values of adjustable parameters was obtained by mathematical analysis of mathematical model. The progress of extraction under different operational conditions can be predicted by these parameters. The effect of solvents and ultrasound was experimentally verified for selected equipments of computing and communication technology. The possibility of separation of chemical warfare agents from the solvent was verified too.
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Rolland, Pauline. "Décontamination du cuir chevelu humain après exposition aux agents chimiques de guerre." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10215.
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Les neurotoxiques organophosphorés sont appelés agents chimiques de guerre car ils sont une menace à la fois pour les militaires et pour les populations civiles. La voie percutanée est l’une des principales voies d’entrée pour ces agents, et plus particulièrement pour le VX, très peu volatil. La décontamination des surfaces exposées est alors cruciale afin d’éviter l’intoxication des victimes. En cas d’attentat terroriste, le cuir chevelu humain pourrait être un site préférentiel d’exposition. Cette partie du corps, riche en follicules pileux, pourrait nécessiter des produits et des processus de décontamination adaptés. Ce travail est divisé en 4 parties : 1) Validation d’un modèle de peau in vitro pour le cuir chevelu humain ; 2) Détermination des stratégies de décontamination ; 3) Formulation de nouveaux systèmes de décontamination ; 4) Évaluation de leur efficacité de décontamination. La peau d’oreille de porc est un modèle pertinent pour l’étude de la pénétration percutanée in vitro du VX à travers le cuir chevelu humain. La peau de dessus de tête de porc représente un bon modèle de cuir chevelu humain pour l’étude de l’affinité du VX avec la tige pilaire. L’étude de distribution du VX selon différents temps d’exposition a montré que la majorité du toxique reste à la surface de la peau jusqu’à 2h d’exposition. Il est donc intéressant de décontaminer la peau même après 2h d’exposition aux agents chimiques de guerre. Les microémulsions comprenant un actif détoxifiant (oxime) sont les systèmes les plus efficaces car ils pénètrent en profondeur afin de venir détruire le toxique in situ dans la peau. Les poudres et les émulsions de Pickering ont une action de surface et permettent d’extraire le toxique présent à la surface de la peau et dans les couches superficielles. Les résultats de nos études in vitro ont montré que ces formulations sont significativement plus efficaces que la terre à foulon pour une décontamination après 45 min d’exposition au VXOrganophosphorous nerve agents are designed as chemical warfare agent because they represent a threat both for the military and the civilians. Due to its low volatility, VX mainly remains in its liquid form and mostly presents a contamination by skin contact. Decontamination of exposed body surface is therefore crucial to prevent victims' poisoning. In case of terrorist acts, civilian human scalp could be a preferential site of exposure. This body region, rich in hair follicles, may require adapted decontamination products and procedures. The aims of this work are: 1) Validation of a relevant in vitro human scalp skin model; 2) Determination of decontamination strategies; 3) Formulation of new decontamination systems; 4) Evaluation of their decontamination efficacy. Pig ear skin is a relevant model when studying the in vitro percutaneous penetration of VX through human scalp. Pig skull roof skin could be used when studying the affinity of VX for hair. This study has shown that most of the nerve agent remains on the skin surface up to 2h of exposure, which means that it is worth decontaminating even if contamination occurred 2h before. Microemulsions loading a detoxifying agent (oxime) are the most efficient systems because they are able to penetrate deeper into the skin to neutralize the agent in situ. Adsorbing powders and Pickering emulsions could interact with the agent present on the skin surface and in the superficial layers. Our results from the in vitro experiments have demonstrated that these formulations are more efficient than Fuller's earth for skin decontamination after 45 min of VX exposure
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Thompson, Vanessa R. "Covalent Protein Adduction of Nitrogen Mustards and Related Compounds." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1152.
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Chemical warfare agents continue to pose a global threat despite the efforts of the international community to prohibit their use in warfare. For this reason, improvement in the detection of these compounds remains of forensic interest. Protein adducts formed by the covalent modification of an electrophilic xenobiotic and a nucleophilic amino acid may provide a biomarker of exposure that is stable and specific to compounds of interest (such as chemical warfare agents), and have the capability to extend the window of detection further than the parent compound or circulating metabolites. This research investigated the formation of protein adducts of the nitrogen mustard chemical warfare agents mechlorethamine (HN-2) and tris(2-chloroethyl)amine (HN-3) to lysine and histidine residues found on the blood proteins hemoglobin and human serum albumin. Identified adducts were assessed for reproducibility and stability both in model peptide and whole protein assays. Specificity of these identified adducts was assessed using in vitro assays to metabolize common therapeutic drugs containing nitrogen mustard moieties. Results of the model peptide assays demonstrated that HN-2 and HN-3 were able to form stable adducts with lysine and histidine residues under physiological conditions. Results for whole protein assays identified three histidine adducts on hemoglobin, and three adducts (two lysine residues and one histidine residue) on human serum albumin that were previously unknown. These protein adducts were determined to be reproducible and stable at physiological conditions over a three-week analysis period. Results from the in vitro metabolic assays revealed that adducts formed by HN-2 and HN-3 are specific to these agents, as metabolized therapeutic drugs (chlorambucil, cyclophosphamide, and melphalan) did not form the same adducts on lysine or histidine residues as the previously identified adducts formed by HN-2 and HN-3. Results obtained from the model peptide and full protein work were enhanced by comparing experimental data to theoretical calculations for adduct formation, providing further confirmatory data. This project was successful in identifying and characterizing biomarkers of exposure to HN-2 and HN-3 that are specific and stable and which have the potential to be used for the forensic determination of exposure to these dangerous agents.
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Boglarski, Stephen L. "Application of hydrogen bond acidic polycarbosilane polymers and solid phase microextraction for the collection of nerve agent simulant /." Download the thesis in PDF, 2006. http://www.lrc.usuhs.mil/dissertations/pdf/Boglarski2006.pdf.
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Vitcher, Sarah. "Mise au point d'une source mixte couplée à un piège linéaire et simulations d'injection axiale et radiale des ions : applications à l'analyse d'agents chimiques." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066571.
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Les menaces constantes de terrorisme nécessitent le développement d'instruments permettant de détecter efficacement des agents chimiques de guerre. L'objectif de ce travail était la réalisation d'un spectromètre de masse devant effectuer des analyses de type : LC/ESI-MS et GC/EI-MS, sur des échantillons sous tous les états : solide, liquide, gazeux et qui soit rapide. Une première partie de ce travail a consisté à étudier le fonctionnement du spectromètre de masse LTQ Velos, puis de faire une étude des modes d'injection axiale et radiale des ions par simulation à l'aide du logiciel SIMION. L'étude de l'injection radiale, nous a démontré la faisabilité de ce mode d'injection dans un piège linéaire. Ainsi, lors d'applications spécifiques dans lesquelles l'axe central doit être libéré, le mode d'activation par IRMPD peut être envisagé. Une deuxième partie de ce travail a consisté à modifier la source CI du module ETD en source EI. Trois sources EI (la Thermo, la NERMAG et la source trappe) ont été étudiées afin de déterminer celle qui serait la plus efficace et offrirait un bon compromis en terme de coût et de temps de développement. La source Thermo a été retenue et a ensuite été implémentée dans le module ETD du LTQ Velos qui a été couplé à un GC rapide pour effectuer des tests préliminaires de faisabilité de ce couplage. Ainsi, ces tests ont permis de caractériser le GC/EI-LTQ Velos comme étant capable d'effectuer des analyses en GC/MS rapide (de l'ordre de ? 5 min). Ce GC/MS rapide a ensuite été intégré dans le démonstrateur ainsi que le collecteur aérien chimique et le détecteur TIC et POC. Des essais préliminaires concluants ont été réalisés sur ce démonstrateurConstant threats of terrorism require the development of tools to effectively detect chemical warfare agents. The aim of this work was to develop a mass spectrometer capable of performing rapid LC/ESI-MS and GC/EI-MS analyses on samples from all states: solid, liquid and gaseous. The first part of this work was to study the principle of operation of the linear ion trap LTQ Velos, then to study axial and radial ion injection in the linear ion trap by means of computer simulation using SIMION. The feasibility of performing radial ion injection has been demonstrated, thus in specific applications in which the central axis needs to be released, the IRMPD activation mode may be considered. A second part of this work was to adapt the existing ETD module to accommodate EI. Three EI sources (the Thermo, the NERMAG and the trap source) were studied to determine which one would be the most effective and offer a good compromise in terms of cost and development time. The Thermo source has been selected and modified to conduct EI within the ETD module of the LTQ Velos which was interfaced to a fast GC (Heracles II). Preliminary tests characterized the dual pressure ion trap as a mass analyzer for performing rapid GC/MS analyses. The results showed that the GC-LIT with its high scanning speed was able to provide sufficient scans across chromatographic peaks when working in both the conventional and the fast GC modes, and further offered good EI spectral information. This GC/MS was then implemented into the demonstrator as well as the air sampler and the TIC/POC detector. Conclusive preliminary tests have been made on this demonstrator
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McDonald, Shannon Scott. "Characterization and optimization of a high surface area-solid phase microextraction sampler for the collection of trace level volatile organic compounds in the field /." Download the thesis in PDF, 2006. http://www.lrc.usuhs.mil/dissertations/pdf/McDonald2006.pdf.
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Koch, David R. "Field and laboratory application of a gas chromatograph low thermal mass resistively heated column system in detecting traditional and non-traditional chemical warfare agents using solid phase micro-extraction /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Koch2005.pdf.
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Kaya, Murat. "Preparation And Surface Modification Of Noble Metal Nanoparticles With Tunable Optical Properties For Sers Applications." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613129/index.pdf.
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Metal nanostructures exhibit a wide variety of interesting physical and chemical properties, which can be tailored by altering their size, morphology, composition, and environment. Gold and silver nanostructures have received considerable attention for many decades because of their widespread use in applications such as catalysis, photonics, electronics, optoelectronics, information storage, chemical and biological sensing, surface plasmon resonance and surface-enhanced Raman scattering (SERS) detection.
This thesis is composed of three main parts about the synthesis, characterization and SERS applications of shape-controlled and surface modified noble metal nanoparticles. The first part is related to a simple synthesis of shape controlled solid gold, hollow gold, silver, gold-silver core-shell, hollow gold-silver double-shell nanoparticles by applying aqueous solution chemistry. Nanoparticles obtained were used for SERS detection of dye molecules like brilliant cresyl blue (BCB) and crystal violet (CV) in aqueous system.
v
The second part involves the synthesis of surface modified silver nanoparticles for the detection of dopamine (DA) molecules. Determination of a dopamine molecule attached to a iron-nitrilotriaceticacid modified silver (Ag-Fe(NTA)) nanoparticles by using surface-enhanced resonance Raman scattering (SERRS) was achieved. The Ag-Fe (NTA) substrate provided reproducibility and excellent sensitivity. Experimental results showed that DA was detected quickly and accurately without any pretreatment in nM levels with excellent discrimination against ascorbic acid (AA) (which was among the lowest value reported in direct SERS detection of DA).
In the third part, a lanthanide series ion (Eu3+) containing silver nanoparticle was prepared for constructing a molecular recognition SERS substrate for the first time. The procedure reported herein, provides a simple way of achieving reproducible and sensitive SERS spectroscopy for organophosphates (OPP) detection. The sensing of the target species was confirmed by the appearance of an intense SERS signal of the methyl phosphonic acid (MPA), a model compound for nonvolatile organophosphate nerve agents, which bound to the surface of the Ag-Eu3+ nanostructure. The simplicity and low cost of the overall process makes this procedure a potential candidate for analytical control processes of nerve agents.
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Rearden, Preshious R. A. "Applications of Solid Phase Microextraction with Ion and Differential Mobility Spectrometry for the Study of Jet Fuels and Organophosphonates." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1142627911.
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Parrish, Douglas K. "Application of solid phase microextraction with gas chromatography-mass spectrometry as a rapid, reliable, and safe method for field sampling and analysis of chemical warfare agent precursors /." Download the dissertation in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Parrish2005.pdf.
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Holman, Charles E. "Predicting biological warfare agent detector performance." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3091.
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Thesis (Ph.D.)--George Mason University, 2008.Vita: p. 232. Thesis director: Andrew Loerch. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biodefense. Title from PDF t.p. (viewed July 7, 2008). Includes bibliographical references (p. 226-231). Also issued in print.
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Brtníková, Jana. "Využití plynové chromatografie ke studiu permeace toxických látek bariérovými materiály." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-233295.
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Transport phenomenon of gas and vapors through polymer barrier materials as well as the factors affecting permeability of gaseous and liquid toxic compounds were investigated and results are presented in this thesis. Permeation characteristics investigation methods were elaborated and verified with focusing on utilization of gas chromatographic method and its instrumental modifications.
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Bignon, Cécile. "Nanoparticules en réseau pour la protection cutanée." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4084/document.
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Les agents chimiques de guerre et leurs dérivés pesticides sont des molécules toxiques qui provoquent une incapacité temporaire ou des dommages permanents allant jusqu’à la mort de l’individu. Une des voies majeures de la contamination est la pénétration cutanée. La protection de la peau semble donc importante pour prévenir de ces dangers. Cette thèse concerne l’élaboration de nouveaux topiques protecteurs cutanés contenant des polymères HASE fluorés greffés avec des nanoparticules de silice, cérine ou titane. Dans un premier temps les actifs ont été synthétisés en grosse quantité et leurs propriétés de mouillabilité améliorées. Les tests toxicologiques ont montré que les actifs n’étaient pas irritants pour la peau et non toxiques pour l’environnement. La formulation de ces polymères a permis le développement de deux nouvelles crèmes barrières contre la pénétration du paraoxon dont l’efficacité est dépendante de la présence des nanoparticules. Le greffage des nanoparticules à un polymère HASE fluoré et leur formulation a donc permis le développement de nouveaux topiques efficaces. L’évaluation de l’efficacité a été réalisée sur membranes artificielles et confirmée sur explants de peaux humaines. Enfin, le peu de disponibilité des explants de peaux humaines a motivé le développement d’un modèle d’efficacité utilisant des épidermes humains reconstruitsChemical warfare agents and pesticides are toxic molecules causing temporary incapacitation or permanent harms leading to the death of people. One of the major routes of contamination is the percutaneous penetration. Skin protection is important to prevent these dangers. The aim of this thesis is to develop new active topical skin protectants based on nanoparticular networks containing fluorinated HASE polymers grafting with silica, cerium or titanium nanoparticles. First, polymers were synthesized in larger quantity and their wettability properties improved. Toxicological studies have showed that these compounds are non-irritant and non-toxic for the environment. The formulation of these polymers has led to the elaboration of two new barrier creams against paraoxon penetration whose efficiency is dependent on the presence of nanoparticles. Therefore, the grafting of nanoparticles to fluorinated HASE polymer and their formulation have enabled the development of new active topical skin protectant. Efficiency evaluation was done using artificial membranes and was confirmed on ex vivo human skin. The limited availability of human skin explants has motivated the development of a new efficiency model using reconstructed human epidermis
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Murray, Jacolin Ann. "High Flow Air Sampling for Field Detection Using Gas Chromatography-Mass Spectrometry." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2414.
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The ability to rapidly detect and identify hazardous analytes in the field has become increasingly important. One of the most important analytical detection methods in the field is gas chromatography-mass spectrometry (GC-MS). In this work, a hand-portable GC-MS system is described that contains a miniature toroidal ion trap mass analyzer and a low thermal mass GC. The system is self-contained within the dimensions of 47 x 36 x 18 cm and weighs less than 13 kg. Because the instrument has a small footprint, it was used as the detector for an automated near-real-time permeation testing system. In permeation testing, materials that are used to make individual protective equipment such as gloves, masks, boots, and suits are exposed to hazardous analytes to determine how long the equipment can be worn safely. The system described herein could test five samples simultaneously. A multi-position valve rotated among the various sample streams and delivered time aliquots into the MS for quantitation. Current field air sampling techniques suffer from long desorption times, high pressure drops, artifact formation and water retention. These disadvantages can be avoided by concentrating the analytes in short open tubular traps containing thick films. There are several advantages to using polymer coated capillaries as traps, including fast desorption, inertness and low flow restriction. An air sampling trap was constructed utilizing open tubular traps for the concentration of semi-volatile organic compounds. The system consisted of multiple capillary traps bundled together, providing high sample flow rates. The analytes were desorbed from the multi-capillary bundle and refocused in a secondary trap. The simultaneous focusing and separation effect of a trap subjected to a negative temperature gradient was also explored. In this configuration, analytes were focused because the front of the peak was at a lower temperature than the rear of the peak and, hence, moved slower. In addition to the focusing effect, analytes with different volatilities focused at different temperatures within the gradient, allowing for separation.
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Chua, Xiang Le. "Derivatisation of chemical warfare agent degradant without removal of water." Thesis, Chua, Xiang Le (2018) Derivatisation of chemical warfare agent degradant without removal of water. Masters by Coursework thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/42915/.
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Degradation products are distinct chemical signature for the detection of chemical warfare agents and forensic attribution in cases where the parent compound no longer exists. Being the common degradant to nerve agents, methylphosphonic acid serves as an explicit biomarker for the use of nerve agents. However, this non-volatile compound requires derivatisation prior to its detection, which incurs time-limiting factor and error. Therefore, development for a novel rapid and simple approach for identifying these degradants is of high importance to shed light on the use of chemical warfare agents and remediation of impacts. With the success of a recent pilot study for derivatisation of methylphosphonic acid without elimination of water, a subsequent quantitative study can be proceeded to assess on its practicality and efficiency.
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Hardy, Pauline. "Synthèse et caractérisation de textiles composites à base de Metal-Organic Frameworks pour la capture et la décomposition d’agents innervant organophosphorés." Electronic Thesis or Diss., Centrale Lille Institut, 2024. http://www.theses.fr/2024CLIL0031.
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Les agents toxiques de guerre restent une menace persistante pour les forces militaires et les civils. Les matériaux poreux sont une réponse efficace pour la capture et l’immobilisation de molécules toxiques. Dans le cas des armes chimiques, des recherches sont menées depuis peu d’années sur les solides de type Metal-Organic Framework (MOF). En effet, ces matériaux microporeux sont dotés d’une porosité élevée, combinée très souvent à des propriétés catalytiques. Ainsi, certains MOFs, notamment ceux à base de zirconium, permettent une capture et une dégradation efficace des toxiques de guerre, dont les agents innervant organophosphorés. Dans le cadre de ce travail de thèse, une étude sur la fonctionnalisation par des MOFs de fibre textile sera réalisée, afin de proposer des composites efficaces protégeant des agents de guerre innervant organophosphorés.Pour la fabrication de ces composites MOF/textiles, le choix s’est porté sur deux support différents, une fibre résistante de type polyester et une fibre à adsorption élevée à base de charbon actif. Cependant, malgré les avantages de ces deux fibres textiles, celles-ci montrent une inertie chimique qui rend difficile le greffage de MOF à la surface du support. Pour surmonter cela, les fibres ont été prétraitées à l’ide de différentes techniques physique ou chimique afin de créer des sites d'ancrage hydrophiles, facilitant ainsi le greffage du MOF à la surface du support. Ces fibres composites ont été ensuite étudiées pour la décomposition du diméthyle 4-nitrophényle phosphate (DMNP) et de l’agent VX (dans le cas du composite à base de polyester uniquement). Enfin, une analyse par Résonnance Magnétique Nucléaire à l’état solide (RMN 31P) a également permis de proposer des mécanismes de décomposition du DMNP, en fonction notamment de l’humidité et de la présence d’un co-catalyseur basiqueToxic warfare agents remain a persistent threat to military forces and civilians. Porous materials are an effective response to capture and immobilize this kind of molecules. In the case of chemical weapons, research has been conducted in recent years on Metal-Organic Framework (MOF) solids. Indeed, these microporous materials have high porosity, usually combined with catalytic properties. Thus, some MOFs, particularly those based on zirconium, allow effective capture and degradation of warfare toxic molecules, including organophosphorus nerve agents. As part of this thesis work, a study on the functionalization of textile fibers by MOFs will be carried out, to propose effective composites protecting organophosphorus nerve agents. For the fabrication of these MOF/textile composites, two different supports were chosen, a resistant polyester fiber and a high adsorption fiber based on activated carbon. However, despite the advantages of these two textile fibers, they show a chemical inertness that makes it difficult to graft MOFs to the surface of the support. To overcome this, the fibers were pretreated using different physical or chemical techniques to create hydrophilic anchoring sites, thus facilitating the grafting of the MOF to the surface of the support. These composite fibers were then studied for the decomposition of dimethyl 4-nitrophenyl phosphate (DMNP) and the VX agent (in the case of the polyester-based composite only). Finally, a solid-state Nuclear Magnetic Resonance (31P NMR) analysis also made it possible to propose decomposition mechanisms of DMNP, depending in particular on humidity and the presence of a basic co-catalyst
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Russell, Scott Chandler. "Real time bio-warfare agent detection using bio-aerosol mass spectrometry /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Thesis (Ph. D.)--University of California, Davis, 2005.Degree granted in Chemistry. Dissertation completed in 2004; degree granted in 2005. Also available via the World Wide Web. (Restricted to UC campuses).
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Van, Horn Tyler G. "The utility of freedom a principal-agent model for unconventional warfare." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5624.
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Approved for public release; distribution is unlimitedThe conduct of warfare through proxies, also known as unconventional warfare, is a difficult feat for a nation to accomplish. The successful employment of surrogate forces depends to a significant degree on the relationships cultivated between the sponsor and the insurgent, and the various actors between the two. This thesis will examine the conduct of an Unconventional Warfare (UW) insurgency campaign from the perspective of Principal-agent Theory. The case study examined will be Operation ST CIRCUS, the Central Intelligence Agency's (CIA) support for Tibetan insurgents from 1956 to 1974. The research will model the principal-agent dynamics of a UW campaign at the global, regional, and local levels, and will demonstrate the options available for the counter-insurgent to indirectly topple the insurgency by destabilizing the relationships between the principal and its agents. By applying Principal-agent Theory concepts to UW, this research will provide a new model for the examination of potential UW campaigns, and potential methods for countering UW campaigns conducted by global adversaries against U.S. interests.
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Gordon, Wesley Odell. "Metal Oxide Nanoparticles: Optical Properties and Interaction with Chemical Warfare Agent Simulants." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29634.
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Materials with length scales in the nanometer regime demonstrate properties that are remarkably different from analogous bulk matter. As a result, researchers are striving to catalog the changes in properties that occur with decreasing size, and more importantly, understand the reason behind novel nanomaterial properties. By learning the true nature of nanomaterials, scientists and engineers can design better materials for a variety of applications. Inert gas-phase condensation synthesis of metal oxide nanoparticles was used to develop materials to explore the optical and chemical properties of metal oxide nanoparticles.
One potential application for nanomaterials is use in optical applications. The possibility of interparticle energy transfer was investigated for lanthanide-doped yttrium oxide nanoparticles using laser spectroscopy. Experimental evidence collected with this study indicates that interparticle, lanthanide-mediated energy transfer may have been observed. In addition, lanthanide-doped gadolinium oxide nanoparticles were synthesized and investigated with optical spectroscopy to identify the best potential candidates for bioanalytical applications of this material. The influence of particle annealing and dopant concentration were also studied.
Nanoparticle film structure was investigated with scanning electron microscopy. Two different film structures composed of oxide nanoparticles were found to grow under different synthesis conditions. The film structure was found to be determined by the degree of particle aggregation in the gas phase during synthesis. Aggregation of the particles was found to be controlled by a combination of gas pressure and properties.
Chemical properties of metal oxide nanoparticles also are very important. Reflection-absorption Infrared Spectroscopy and vacuum surface analytical techniques were used to explore the chemistry of the chemical warfare agent dimethyl methylphosphonate (DMMP) on yttrium oxide as well as other metal oxide nanoparticles. DMMP was found to dissociate at room temperature on several types of metal oxide nanoparticles. Hydroxyl groups were found to be critical for the adsorption of DMMP onto the particles. Finally, the reactivity of the nanoparticles was found to increase with decreasing particle size. This was attributed to a relative increase in the number of high-energy surface defects for the smaller particles.Ph. D.
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Ipekci, Arif Ilker. "How agent based models can be utilized to explore and exploit non-linearity and intangibles inherent in guerrilla warfare." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FIpekci.pdf.
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Richardson, Douglas Dennis. "Modern advancements in elemental speciation from sample introduction to chemical warfare agent detection /." Cincinnati, Ohio : University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1250178457.
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Thesis (Ph.D.)--University of Cincinnati, 2007.Advisor: Joseph A. Caruso. Title from electronic thesis title page (viewed Apr. 30, 2010). Keywords: Elemental Speciation; ICPMS; Chemical Warfare Agents; Phosphorus; Liquid Chromatography; Gas Chromatography; Capillary Electrophoresis. Includes abstract. Includes bibliographical references.
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Kan, WaiKwong. "Hapsite (R) gas chromatography - mass spectrometry with solid phase microextraction /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Kan2005.pdf.
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Webb, Jamie Pauline. "Political Poison: Agent Orange in Congress 1940-1991." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2538.
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This paper examines the evolution of government policy through Congressional debate and citizen involvement on the topic of Agent Orange. Use of primary sources from newspaper and journal articles, Congressional records, scientific studies, and press releases and some secondary literature by scholars from multiple disciplines builds a picture of the ongoing debate of Agent Orange and its two component herbicides from circa 1940 to 1991. Within this paper are four primary focuses, divided into three parts. First, the Congressional discussions prior to 1970 of 2,4-D and 2,4,5-T, the two herbicides that comprise Agent Orange. Second and third, discussed in the same section, the involvement of the scientific community and the ratification of the Geneva Protocol. Lastly, the movement after the Vietnam War for veteran benefits due to Agent Orange exposure.
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Sundberg, Jeffrey P. "U.S. chemical warfare stockpile vulnerability effects to local infrastructure from a chemical-agent release." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FSundberg.pdf.
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McKeown, Jason L. "Analyzing the Surface Warfare Operational Effectiveness of an Offshore Patrol Vessel using Agent Based Modeling." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/17415.
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Approved for public release; distribution is unlimitedWith the increasing emphasis of asymmetric tactics employed by terrorist organizations and extremist militants, the development of fast and capable naval combatants has become the focus of many navies around the world. Predominately aimed at the defense of the littorals, these smaller naval combatants must be able to establish maritime dominance at an affordable price, given constrained defense budgets. The Offshore Patrol Vessel is one such ship type that can meet these needs. This thesis explores the development of a Map Aware Non-Uniform Automata agent based simulation in an Anti-Surface Warfare environment. Insights gained through the models indicate that OPVs placed in a small boat swarm scenario will be hard pressed to successfully defend an object if not sufficiently armed to combat the threat. While the weapon systems placed on OPVs have a significant impact on simulation results, additional factors indicate that interactions between associated OPV systems and outside contributors are also vital.
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McPherson, Melinda Kay. "The Reactivity of Chemical Warfare Agent Simulants on Carbamate Functionalized Monolayers and Ordered Silsesquioxane Films." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26793.
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The reactivity of chemical warfare agents (CWAs) and CWA simulants on organic and oxide surfaces is not currently well understood, but is of substantial importance to the development of effective sensors, filters and sorbent materials. Polyurethane coatings are used by the armed forces as chemical agent resistive paints to limit the uptake of CWAs on surfaces, while the use of metal oxides has been explored for decontamination and protection purposes. To better understand the chemical nature of the interactions of organophosphonate simulants with these surfaces, an ultra-high vacuum environment was used to isolate the target interactions from environmental gaseous interferences. The use of highly-characterized surfaces, coupled with molecular beam and dosing capabilities, allows for the elucidation of adsorption, desorption, and reaction mechanisms of CWA simulants on a variety of materials.
Model urethane-containing organic coatings were designed and applied toward the creation of well-ordered thin films containing carbamate linkages. In addition, novel trisilanolphenyl-polyhedral oligomeric silsesquioxane (POSS) molecules were used to create Langmuir-Blodgett films containing reactive silanol groups that have potential use as sensors and coatings. The uptake and reactivity of organophosphonates and chlorophosphates on these surfaces is the focus of this study.
Surfaces were characterized before and after exposure to the phosphates using a number of surface sensitive techniques including: contact angle goniometry, reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) measurements. In conjunction with surface probes, uptake coefficients were monitored according to the King and Wells direct reflection technique. The integration of these analytical techniques provides insight and direction towards the design of more effective chemical agent resistant coatings and aids in the development of more functional strategies for chemical warfare agent decontamination and sensing.Ph. D.