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EVALUATION OF THE OXIDATIVE METABOLITES OF ARACHIDONIC ACID AND THEIR IMPLICATION IN THE PROGRESSION OF INFLAMMATORY DISEASES: HYPERTENSION AND RHEUMATOID ARTHRITISVarma, Deepti January 2012 (has links)
Inflammation is implicated in diseases such as hypertension and rheumatoid arthritis (RA). A mechanistic understanding of inflammatory processes as it relates to the disease state and injury needs to be developed. Specifically, the role and modulation of inflammation needs to be assessed, as well as the mechanism that produces arachidonic acid (AA) metabolites (eicosanoids). Eicosanoids are specific biomarkers of inflammation. Their biosynthesis from arachidonic acid can be catalyzed by either free radicals or enzymes such as lipoxygenases (LOX), cyclooxygenase-2 (COX-2) and cytochrome P450. Depending on the pathway or parent molecule, different distributions of eicosanoids are found. The oxidation of AA gives hydroxyeicosatetraenoic acids (HETEs), dihydroxyeicosatetraenoic acids (DHETEs), epoxyeicosatetraenoic acids (EETs), prostaglandins (PGs), isoprostanes (Isops) and thromboxanes (TXs). It is our hypothesis that AA metabolites will help in understanding the progression of inflammatory diseases. To confirm this hypothesis, analytical methods including HPLC-UV and LC-MS were developed. The developed and validated HPLC method was applied to study the effect of acute exercise on prostanoids in hypertensive African American subjects. It was our theory that urinary 6-keto PGF1&alpha and 11-dehydro TXB2 can be used to assess the role of exercise in hypertension. Moreover, we assume that 8-iso PGF2 levels can be used as an indicator to determine the relationship of oxidative stress and endothelial dysfunction in hypertension. The HPLC method involved separating urinary 8-iso PGF2, PGE2, PGD2, PGF2, 6-keto PGF1&alpha and 11-dehydro TXB2 on a SymmetryShield Rp18 column (250mm ¡Á 4.6mm) by an isocratic elution of 17 mM phosphoric acid and acetonitrile in the ratio of 65:35 and at a flow rate of 1.3 ml/min. The wavelength used for detection was 196 nm. Specificity was confirmed by LC-MS. The method was fully validated and was found to be having sufficient sensitivity (limit of quantification - 7.5 ng - 30 ng) for many biological matrices and applications. The accuracy and precision were within bioanalytical method validation limits (90.3 to 112.8 % and RSD < 10%, respectively) and the method was linear over three orders of magnitude. In addition, a HPLC-UV method for the simultaneous determination of urinary creatinine and prostanoids was also developed and validated as it is necessary to monitor creatinine levels in addition to biomarkers when the measurement is done in urine. The method was found to be linear over three orders of magnitude and is sensitive enough for the analysis of creatinine and prostanoids in urine. The advantage of this method was that one can determine the levels of these prostanoids normalized by urinary creatinine in a single analysis and in less than 17 min. The LC- ESI (electrospray ionization) MS method, on the other hand was used to determine the role of HETEs in the initiation, progression and resolution phases of inflammation in RA. It is our assumption that 12/15 HETE can be used as novel targets for the treatment of RA. The separation was performed on a C18 column using a gradient elution of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. The flow rate was 1 ml/min and the run time was 75 mins. The method was found to be specific, sensitive and precise. This LCMS method was also used to develop a retention model for complex regioisomers. Quantitative structure- (chromatographic) retention relationship (QSRR) was used to develop a predictive retention model for fatty acid metabolites. Retention behaviors of the lipid biomarkers were characterized by application of QSRR analysis utilizing Austin Model 1 mode semi-empirical computations. The retention data of these fatty acids were obtained from an RP-HPLC method utilizing a Symmetry C18 column under gradient elution. Molecular descriptors that take into account the polarity; chemical reactivity and hydrophobicity of the analytes were calculated using the semi-empirical AM1 mode. It is our hypothesis that QSRR will give insight into molecular mechanism of separation of lipid biomarkers operating in a given chromatographic system and can predict retention of a new analyte and/or to identify unknown analytes. / Chemistry
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Determination of Fine Particulate Matter Composition and Development of the Organic Aerosol MonitorCropper, Paul Michael 02 June 2016 (has links)
<p>Tropospheric fine particulate matter (PM) poses serious health risks and has a significant impact on global climate change. The measurement of various aspects of PM is challenging due to its complex chemical nature. This dissertation addresses various aspects of PM, including composition, measurement, and visibility. The U.S. Environmental Protection Agency (EPA) proposed a new secondary standard based on visibility in urban areas using 24-h averaged measurements of either light scatter or PM concentration. However shorter averaging times may better represent human perception of visibility. Data from two studies conducted in Lindon, UT, 2012, and Rubidoux, CA, 2003, were used to compare different techniques to estimate visibility, particularly the effect of relative humidity on visibility estimations. Particle composition was measured in Salt Lake City during January-February of 2009. One-hour averaged concentrations of several gas phase and particle phase inorganic species were measured. The results indicate ammonium nitrate averages 40% of the total PM2.5 mass in the absence of inversions and up to 69% during strong inversions. Also, the formation of ammonium nitrate is nitric acid limited, while the formation of ozone appears to be oxidant and volatile organic carbon (VOC) limited. Reduction of NOx will reduce ammonium nitrate secondary particle formation, however, a decrease in NOx may increase ozone concentration. </p><p> Due to the complexity of PM it is poorly characterized. A large fraction of PM is composed of organic compounds, but these compounds are not regularly monitored due to limitations in current sampling techniques. The GC-MS Organic Aerosol Monitor (OAM) combines a collection device with thermal desorption, gas chromatography and mass spectrometry to quantitatively measure the carbonaceous components of PM on an hourly averaged basis. A compact GC and simple pre-concentrator were developed for the system to decouple separation from manual injection and enhance separation of environmentally-relevant polar organic compounds, such as levoglucosan. The GC-MS OAM is fully automated and has been successfully deployed in the field. It uses a chemically deactivated filter for collection followed by thermal desorption and GC-MS analysis. Laboratory tests show that detection limits range from 0.2 to 3 ng for many atmospherically relevant compounds. The GC-MS OAM was deployed in the field for semi-continuous measurement of the organic markers, levoglucosan, dehydroabietic acid, and several polycyclic aromatic hydrocarbons (PAHs) during winter (January to March), 2015 and 2016. Results illustrate the significance of this monitoring technique to more fully characterize the organic components of PM and identify sources of pollution. </p><p> Keywords: air pollution, fine particulate matter, PM<sub>2.5</sub>, secondary organic aerosol, organic markers, levoglucosan, PMF. </p>
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Detection of decontamination solution chelating agents using ion selective coated-wire electrodesBanks, Mark Lavoir, 1960- January 1992 (has links)
It is the purpose of this thesis to explore the feasibility of using coated-wire electrodes to measure chelating agent concentration. Chelating agents are often found in radioactive decontamination solutions because they aid in the removal of radionuclides from contaminated surfaces by increasing their solubility. However, this characteristic will also enhance the mobility of the radionuclide and thus its transport out of a waste disposal site. Coated-wire ion selective electrodes, based on a polyvinylchloride membrane using dioctylphthalate as a plasticizer and dinonylnaphthalene-sulfonic acid as a counterion, were constructed for five commonly utilized chelating agents (ethylenediaminetetracetic acid (EDTA), nitrilotriacetic acid (NTA), citric acid, oxalic acid and tartaric acid). The EDTA and NTA electrodes' calibration characteristics exhibited acceptable behavior in pure standard solutions. From data obtained while using the EDTA and NTA electrodes in a cement environment, further research needs to be done in the area of ion interference.
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Raman spectroscopic studies of calcium-phosphate, aluminum metaphosphate-sodium fluoride and calcium metaphosphate-calcium fluoride glassesLatifzadeh, Lida, 1956- January 1990 (has links)
The role of modifier on the molecular structure of Ca-phosphate, sodium fluorophosphate and sodium aluminophosphate glasses have been investigated by Raman spectroscopy. Ca-phosphate glasses for this study have the molar ratio of CaO/P₂O₅ from 1.00 to 1.50. Curve fitting procedures have been used to resolve the overlapped peaks for accurate interpretation. Amorphous species with varying chain lengths and two crystalline phases of γ- and α-Ca₂P₂O₇ have been identified. Sodium fluorophosphate glasses have been prepared from the reaction between Al(PO₃)₃ and NaF. The molar ratio of Na/P is varied from 0.900 to 2.00 and the F/P ratio is from 0.510 to 1.61. By studying the vibrational frequency shifts, species with varying phosphorus and fluorine contents and aluminophosphate compounds have been identified.
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Characterization and optimization of ordering in thin films of 2,3,9,10,16,17,23,24-oktakis((2-benzyloxy)ethoxy)phthalocyaninato copper and its metal free analoguePeterson, Rebecca Anne, 1973- January 1998 (has links)
The variables which control the degree of molecular ordering of CuPc(OC₂OBz)₈ and H₂Pc(OC₂OBz)₈ within Langmuir-Blodgett (LB) thin films were identified and optimized. Stabilizing the Langmuir film, lowering the subphase temperature, transferring to phenyl terminated substrates, and annealing lead to enhanced ordering. Infrared data confirms increased anisotrophy (dichroic ratio, R-4.6) and order (order parameter, S₂-6.5) within these films, and predicts a tilted elliptical orientation of the molecules. Small angle X-ray scattering data and atomic force microscopy images correlate, giving a column-to-column spacing of ca. 27Å and ca. 29Å, respectively. Ordered LB thin films have charge transport mobilities of ca. 1x10⁻⁴cm²V⁻¹s⁻¹ that may increase with ClO⁻₄ anion insertion. The degree of achieved ordering leads to further investigations into the applicability of LB thin films of CuPc(OC₂OBz)₈ and H₂Pc(OC₂OBz)₈ in molecular electronic devices.
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Synthesis, Optical and Structural Characterization, and Exciton Dynamics of Doped ZnSe Nanocrystals, and, Simultaneous X-ray Emission Spectroscopy of Two Elements Using Energy Dispersive SpectrometerGul, Sheraz 24 September 2014 (has links)
<p> Doped semiconductor quantum dots (QDs) comprise an important subclass of nanomaterials in which a small quantity of impurity is added intentionally, adding another degree of freedom to alter their size-dependent physical and electronic properties. Intense, tunable, long lived and stable photoluminescence make them quintessential candidates for many opto-electronic applications including solid-state lighting, display devices and biomedical imaging. ZnSe QDs, which are blue-emitting fluorophores, were doped with Cu<sup>+1</sup> to redshift their photoluminescence (PL) to green region of the visible spectrum. These Cu-doped ZnSe QDs were then codoped with Al<sup>3+</sup>, Ga<sup> 3+</sup> and In<sup>3+</sup> to improve the PL quantum yield (QY) by eliminating the defect states originating from charge imbalance created by aliovalent doping. Codoping also resulted in further redshifting of the PL, covering most of the visible spectrum, making them potential candidates for use in solid-state lighting and as optical down converters in next generation light emitting diodes (LEDs). To better understand the optical properties of these materials, local structure around the luminescent centers was investigated by extended X-ray absorption fine structure (EXAFS). Cu was found to occupy a distorted tetrahedral site with the codopant residing in a substitutional Zn site. Based on the structural information obtained by EXAFS, density functional theory calculations (DFT) were performed to get a clear picture of the energy levels associated with the electronic transitions. Furthermore, the dynamics studies of the exciton and charge carriers were carried out to get deeper insight of the various photophysical processes involved. The fluorescence lifetime was increased approximately 10 times after doping. </p><p> The multielectron catalytic reactions often involve multimetallic clusters, where the reaction is controlled by the electronic and spin coupling between metals and ligands to facilitate charge transfer, bond formation/breaking, substrate binding, and release of products. A method was developed to detect X-ray emission signal from multiple elements simultaneously to probe the electronic structure and sequential chemistry that occurs between the elements. A wavelength dispersive spectrometer based on the von-Hamos geometry was used, that disperses Kβ emission signals of multiple elements onto an area detector, and enables an XES spectrum to be measured in a single-shot mode. This overcomes the scanning needs of the Rowland circle spectrometers, and the data is free from temporal and normalization errors, and therefore ideal to follow sequential chemistry at multiple sites. This method was applied to MnO<sub>x</sub> based electrocatalysts, and the effect of Ni addition was investigated. Electro-deposited Mn oxide catalyses oxygen-evolution reaction (OER) and oxygen-reduction reaction (ORR) at different electrochemical potentials under alkaline condition. Incorporation of Ni reduced the low valent Mn component resulting in higher average oxidation state of Mn in MnNiOx under ORR and OER conditions, when compared to MnO<sub> x</sub> under similar conditions. The reversibility of the electrocatalyst was also found to improve by the inclusion of Ni.</p>
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Kinetics and characterization of conducting and insulating polymers by in situ and ex situ techniquesUnknown Date (has links)
The kinetics of polypyrrole, polyaniline, polystyrene and polyurethane syntheses were examined using in-situ techniques. The resulting polymers were analyzed by ex-situ analytical techniques. Comparison of results obtained by different techniques was made. / Polypyrrole was synthesized by the chemical oxidative route. The polymerization using potassium ferricyanide was monitored by Raman spectroscopy, potentiometry and microelectrode analysis. The kinetics were found to resemble exponential decay. The stoichiometry of the polymerization was 2.5 ferricyanide per pyrrole that polymerized and remained constant throughout the experimental period. / The polymerization of aniline by ammonium peroxysulfate was monitored by Raman, potentiometry, calorimetry, quartz crystal microbalance (QCM), conductance measurements, viscometry and visible absorption spectroscopy. QCM and visible absorption spectroscopy were used to probe the nucleation stage. The results showed that polymerization occurred following an induction period. The stoichiometry of aniline polymerization was found to be 1.2 peroxysulfate per aniline consumed. / The induction period of aniline-peroxysulfate system can be reduced by using mixed oxidizers. In the experiment, cerium (IV) was used as co-oxidant with peroxysulfate. A significant decrease in the induction period was observed with 0.01% of cerium (IV). The same effect can also be achieved by adding polyaniline to provide reaction sites for the monomers. / The kinetics of styrene polymerization were monitored by Raman. The decrease in the 1630 cm$\sp{-1}$ aliphatic C=C stretching was interpreted as percent styrene conversion. The 1600 cm$\sp{-1}$ aromatic C=C stretching was used as an internal standard. UV absorption spectroscopy (UV) was used to quantify the amount of styrene in the polymerizing mixture. / IR spectroscopy (IR) and Raman were used to monitor the reaction of modified diphenylmethane-4-4$\sp\prime$-diisocyanate (MDI) and polyether polyol (polyol). The area under the isocyanate IR stretching peak was quantified using the C-H stretching peak as internal standard. In the Raman experiment, the decrease in the 1060 cm$\sp{-1}$ Raman feature and the increase in the 1140 cm$\sp{-1}$ peak were analyzed. / Source: Dissertation Abstracts International, Volume: 54-03, Section: B, page: 1371. / Major Professor: Joseph B. Schlenoff. / Thesis (Ph.D.)--The Florida State University, 1993.
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Spectroscopic studies of lanthanide complexes with organic ligandsUnknown Date (has links)
The effect of concentration of Eu(III) on its lumnescence decay constant and complexation of trivalent lanthanides with aromatic (mellitic, pyromellitic, hemimellitic, trimellitic, trimesic, phthalic, isophthalic, terephthalic and benzoic) and aliphatic (malonic, succinic, glutaric and adipic) carboxylic acids and ethylenediamine were studied by luminescence, absorption and NMR spectroscopic methods and luminescence lifetime measurements. / At constant ionic strength (0.1 M NaClO$\sb4$), Eu(III) luminescence decay constant increases as its concentration decreases from 0.2 M to 10$\sp{-5}$ M while the Eu(III) $\rm\sp7F\sb0\to$ $\sp5D\sb0$ excitation spectra were unchanged. / Both luminescence spectra and decay constants indicate that mellitate, pyromellitate, hemimellitate, trimellitate, trimesate and terephthalate form ML complex while phthalate, isophthalate, benzoate and the aliphatic dicarboxylates form ML and ML$\sb2$ complexes at 25$\sp\circ$C and 0.1 M ionic strength (0.1 M NaClO$\sb4$). Using the SQUAD program, stability constants of Eu(III) with above carboxylate ligands were calculated from the $\rm\sp7F\sb0\to$ $\sp5D\sb0$ excitation spectra of Eu(III). The luminescence decay constants indicate that aromatic carboxylates with adjacent carboxylates groups are bidentate and replace two water molecules upon complexation. Benzoate and terephthalate are unidentate. Isophthalate and trimesate replace ca. 1.5 water molecules. For the aliphatic dicarboxylates, as the carbon chain increases, the number of water molecules released from the inner sphere upon complexation decreases from 2.7 (malonate) to 1.8 (adipate). / The oscillator strengths of Nd(III) and Ho(III) complexes with carboxylates in the hypersensitive trantion ranges were calculated and the relationships between stability constant, oscillator strength and ligand basicity were examined. / Luminescence and NMR studies show that Eu(III) forms ML, ML$\sb2$, and ML$\sb3$ complexes with ethylenediamine in DMSO. The quenching effect of N-H on Eu(III) and Tb(III) luminescence is linearly proportional to the number of N-H groups in the inner sphere of the metal ion. / It was found that formation of Eu(III) complexes causes shift of the maxima of Eu(III) $\rm\sp7F\sb0\to$ $\sp5D\sb0$ excitation spectra towards lower frequency. The magnitude of the shift linearly correlates with the total ligand coordination number. / Source: Dissertation Abstracts International, Volume: 55-08, Section: B, page: 3305. / Major Professor: G. R. Choppin. / Thesis (Ph.D.)--The Florida State University, 1994.
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The rapid synthesis of x-ray pure yttrium barium(2) copper(3) oxygen(7)Unknown Date (has links)
This paper describes a variation of the oxalate procedure that has significant advantages. The oxalate approach is often used to produce rare earth 123 superconductors and related ceramics. A moderately high concentration of acetone changes the dielectric character of the solution significantly and in the process greatly modifies the solubility of the oxalate compounds. / When oxalic acid or oxalate ions are added to a yttrium-barium-copper aqueous solution, significant amounts of the metal (typically 10-40% of either Cu or Ba depending upon the pH) are left in solution. Such losses result in poor quality material. The acetone makes the precipitation more than 99+% complete. The oxalate precursor thus produced by this route fires to high quality superconductors in amazingly short periods of time. / Source: Dissertation Abstracts International, Volume: 53-10, Section: B, page: 5175. / Major Professor: Ronald J. Clark. / Thesis (Ph.D.)--The Florida State University, 1992.
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Extension of principal component self-modeling analysis and conformational isomerismUnknown Date (has links)
Fluorescence and fluorescence-excitation spectra of trans-1-(2-naphthyl)-2-phenylethene (NPE), obtained under varying conditions of excitation and emission wavelengths, respectively, and oxygen concentration in methylcyclohexane are resolved into two distinct components by application of principal component analysis with self-modeling (PCA-SM). Resolved conformer fluorescence-excitation spectra are confirmed by use of an excitation-fluorescence/fluorescence two dimensional matrix. These spectra are used to decompose the UV absorption spectrum of NPE into conformer specific absorption spectra based on the assumption of excitation-wavelength independent fluorescence quantum yields for the individual conformers. / The first extension of PCA-SM to four component systems is presented. It is based on the assumption of minimum non-negativity of the spectral elements as given by Lawton and Sylvestre. Self-modeling curve resolution for a simulated four component system is accomplished by the projection of a 4-D tetrahedron in 4-D space to a 3-D tetrahedron in 3-D space. Explicit extension of the self-modeling technique to a four component case is described. Simulated data matrices having different S/N ranges as well as different spectral shapes and various spectral resolutions were employed to test the applicability of the method. / Fluorescence spectra of NPE obtained at different excitation wavelengths and tri-n-butylamine (TBA) concentrations (0.00 M-0.30 M) in methylcyclohexane were resolved into fluorescence spectra of the NPE conformers and of the two NPE-TBA exciplexes by use of principal component analysis combined with a four component self-modeling technique. Stern-Volmer constants, $K\sb{\rm svm},$ obtained from monomer fluorescence quenching and exciplex formation are 4.5 M$\sp{-1}$ and 24.66 $\pm$ 4.56 M$\sp{-1}$ for NPE$\sb1$ and NPE$\sb2,$ respectively. The fluorescence of the two exciplexes is quenched by TBA differentially with $K\sb{\rm sve2}$ = 0.85 $\pm$ 0.13 M$\sp{-1}$ and $K\sb{\rm sve1}$ is significantly larger than $K\sb{\rm sve2}.$ / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5735. / Major Professor: Jack Saltiel. / Thesis (Ph.D.)--The Florida State University, 1992.
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