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Although existing research has evaluated physiological and environmental risk factors for depression, these processes are often examined in isolation without considering the dynamic relationships in risk for depression. The present study evaluated physiological markers of resting and stress-reactive respiratory sinus arrhythmia (RSA and RSA reactivity) as predictors of depressive symptoms and interpersonal stress generation, a mutable and potent vulnerability for depression. Further, we examined whether stress generation predicted subsequent depressive symptoms. In a sample of late adolescents (N = 105; 18-22 years; 76% female), individuals who screened in for a history of clinical and subclinical depression participated in a micro-longitudinal assessment with a diagnostic interview, in-laboratory socio-evaluative stressor task, and two weeks of daily assessments of stressful events and depressive symptoms. First, results indicated that there were no clinical or physiological differences between individuals with a clinical or subclinical depression history. Our multilevel modeling analyses revealed that: 1) only lower levels of resting RSA predicted depressive symptoms over the two-week period; 2) only lower RSA reactivity predicted greater interpersonal stress generation, but not independent stressors; 3) interpersonal stress generation mediated the relationship between RSA reactivity and depressive symptoms, but not resting RSA and depressive symptoms; 4) sex differences only occurred in the relationship between resting RSA and depressive symptoms; and 5) there were no interactive effects of resting RSA and RSA reactivity on depression or interpersonal stress generation. These findings highlight the importance of assessing both resting RSA and RSA reactivity in the examination of depression and depression-related processes. / Psychology

The goal of this research was to develop alternate economic routes for the synthesis of functionalised triarylphosphines. Such species are employed as catalysts ligands in chemical synthesis and can be incorporated into designed-ylides for olefination reactions. The synthesis of the SHOP ligand, the key constituent of the Shell Higher Olefins Process for making linear alpha olefins via ethylene oligomerisation and olefin metathesis, is described using four totally new approaches. These include a Directed Ortho Metalation (DOM) approach, Copper iodide catalyzed cross-coupling, Halogen-Magnesium Exchange reaction and Diazonium salt approaches. The efficiency, in terms of overall yield and mild process conditions, make some of the routes potentially commercialisable. Additionally, a series of ortho-substitued triarylphosphines were derived to probe and modulate the reactivity of the Wittig reaction. We report that non-stabilized ortho-P-alkoxy-substituted ylides react with aromatic and aliphatic aldehydes providing (E)-olefins with high stereocontrol employing an intramolecular phenoxy and alkoxy substituent to promote (E)-olefination through betaine interconversion. In one particular case; removal of phosphoine oxide was also achieved. Extension of this methodology was also carried out on semi-stabilized benzylic ylides, which are known for producing 1:1 mixtures of (E):(Z) olefins under classical condition. Potential applications of the methodology are also described. / Thesis / Master of Science (MSc)

No / Reactivity to assessment has attracted recent attention in the brief alcohol intervention literature. This systematic review sought to examine the nature of change in alcohol consumption over time in control groups in brief intervention studies. Primary studies were identified from existing reviews published in English language, peer-reviewed journals between 1995 and 2005. Change in alcohol consumption and selected study-level characteristics for each primary study were extracted. Consumption change data were pooled in random effects models and meta-regression was used to explore predictors of change. Eleven review papers reported the results of 44 individual studies. Twenty-six of these studies provided data suitable for quantitative study. Extreme heterogeneity was identified and the extent of observed reduction in consumption over time was greater in studies undertaken in Anglophone countries, with single gender study participants, and without special targeting by age. Heterogeneity was reduced but was still substantial in a sub-set of 15 general population studies undertaken in English language countries. The actual content of the control group procedure itself was not predictive of reduction in drinking, nor were a range of other candidate variables including setting, the exclusion of dependent drinkers, the collection of a biological sample at follow-up, and duration of study. Further investigations may yield novel insights into the nature of behaviour change with potential to inform brief interventions design.

This dissertation describes the current and common problem of removing low concentrations of pollutants known as volatile organic compounds (VOCs) from large volume gas emissions. Silica-supported manganese oxide catalysts with loadings of 3, 10, 15, and 20 wt. % (as MnO2) were characterized using x-ray absorption spectroscopy and x-ray diffraction (XRD). The edge positions in the x-ray absorption spectra indicated that the oxidation state for the manganese decreased with increasing metal oxide loading from a value close to that of Mn2O3 (+3) to a value approximating that of Mn3O4 (+2⅔). The XRD was consistent with these results as the diffractograms for the supported catalysts of higher manganese oxide loading matched those of a Mn3O4 reference. The reactivity of the silica-supported manganese oxide catalysts in acetone oxidation using ozone as an oxidant was studied over the temperature range of 300 to 600 K. Both oxygen and ozone produced mainly CO₂ as the product of oxidation, but in the case of ozone the reaction temperature and activation energy were significantly reduced. The effect of metal oxide loading was investigated, and the activity for acetone oxidation was greater for a 10 wt. % MnOx/SiO2 catalyst sample compared to a 3 wt. % MnOx/SiO2 sample. A detailed mechanistic study of acetone oxidation using ozone was performed on a 10 wt. % silica-supported manganese oxide catalyst utilizing Raman spectroscopy, temperature programmed desorption (TPD), and kinetic measurements. In situ Raman spectroscopy at reaction conditions identified a band at 2930 cm-1 due to an adsorbed acetone species on the silica support and a band at 890 cm-1 due to an adsorbed peroxide species on the manganese oxide. A steady-state kinetic analysis, which varied acetone partial pressure (101 – 405 Pa), ozone partial pressure (101 – 1013 Pa), and temperature (318, 333, 343, and 373 K), was used to determine reaction rate expressions, while a transient kinetic study (318 K) was used to determine the role of the adsorbed species in the reaction mechanism. It was found that the rates of the acetone and ozone reactions were equally well described by both a power rate law and a Langmuir-Hinshelwood expression. The transient experiments showed that the rates of formation and reaction of the observed peroxide surface species did not correspond to the overall reaction rate, and it was concluded that it was not directly involved in the rate determining step of the reaction. A mechanism is proposed involving the reaction of an adsorbed acetone intermediate with an atomically adsorbed oxygen species via a dual site surface reaction to form complete oxidation products. / Ph. D.

Anger and hostility have been attributed as early risk factors of coronary heart disease (CHD). However, many inconsistencies exist in the literature linking both of these constructs to CHD, as well as to cardiovascular reactivity (CVR) to stressors likely to give rise to CHD. A potential moderating influence discussed in the CVR literature concerns the issue of anger provocation, whereas assessment of the ability to evaluate the source of provocation may moderate the recovery process. The current study adopts a multivariate approach to assess the interactive effects of dispositional anger in predicting the CVR and recovery to mental arithmetic (MA) stress with and without harassment in 47 male undergraduate psychology students. Results revealed anger out (AO) to be associated with high vagal and low frequency power suppression in response to the MA task with harassment. Exposure to experimenter evaluation was associated with attenuated diastolic blood pressure recovery and facilitated vagal recovery in high AO subjects, whereas the opposite pattern was apparent for low AO subjects. The general findings suggest that trait anger interacts with situational influences to predict CVR and recovery to stressors. / Ph. D.

Endohedral metallofullerenes (EMF) have attracted increasing attention during past decades for their potential applications in the fields of biomedicine and nanomaterials. Trimetallic nitride template endohedral metallofullerenes (TNT EMFs) are some of the most promising fullerene-based materials (e.g., as MRI and X-ray contrast agents) because of their high yields compared to classic endohedral metallofullerenes. This dissertation addresses the chemical reactivity and regioselectivity of TNT EMFs. Based on the extraordinarily high stability of TNT EMFs relative to empty cage fullerenes and classic endohedral metallofullerenes, macroscopic quantities of high purity TNT EMFs were obtained directly from crude soot in a single facile step by using a cyclopentadiene-functionalized resin to trap the more reactive species via Diels-Alder reactions, allowing the TNT EMFs to pass through. We also developed a support-free chemical separation method of TNT EMFs from Sc- and Lu-based soot extract that makes use of the differing solubilities of unreacted TNT EMFs versus 9-methylanthracene-derivatized empty cage fullerenes. The exohedral functionalization of metallofullerenes can fine-tune their chemical and physical properties. The first N-methylpyrrolidino derivatives of TNT EMFs (Ih Sc3N@C80 and Ih Er3N@C80) were synthesized via 1,3-dipolar cycloaddition of N-methylazomethine ylides (Prato reaction). The demonstration of planar symmetry in the N-methylpyrrolidino derivatives by 13C NMR spectroscopy suggested that the reaction exclusively took place at the 5,6-ring junction. However, both 5,6-ring and 6,6 ring junction adducts were obtained when Ih Sc3N@C80 reacted with N-triphenylmethyl-5-oxazolidinone, as characterized by NMR spectroscopy and X-ray crystallography. The kinetically favored 6,6-ring junction adduct was converted to the thermodynamic product, the 5,6-ring junction adduct, upon thermal equilibration. The synthesis of pyrrolidino derivatives was also extended to two other Sc-based TNT EMFs, D5h Sc3N@C80 and Sc3N@C78. The reactivity and regioselectivity of D5h Sc3N@C80 and Sc3N@C78 were demonstrated by NMR spectroscopy, X-ray crystallography and theoretical calculations. Another type of reaction, the Bingel-Hirsch cyclopropanation was carried out with D3h Sc3N@C78 for the first time, yielding a single Cs-symmetric monoadduct and a dominant C2v-symmetric diadduct for the first time. The symmetric diadduct clearly demonstrates the remarkable regioselectivity control exerted by the encapsulated Sc3N cluster. We employed a LUMO electron density surface computational approach to predict multiadduct docking sites on the ellipsoidal fullerene cage surface. We also successfully synthesized the first derivative of a non-IPR fullerene, the diethyl malonate derivative of Sc3N@C68 by a Bingel-Hirsch reaction. The reactivity and regioselectivity of Sc3N@C68 were investigated by NMR spectroscopy and theoretical calculations. / Ph. D.

The scope and limitations of aromatic diazines undergoing nucleophilic substitution reactions occurring via a radical-chain Sʀɴ1 mechanism were investigated. The study was conducted on a series of mono- and dihalogenated aromatic diazines interacting with various ketone enolates in ammonia. Results indicate that this previously unrecognized reaction pathway in these nitrogen heterocycles is easily obtained and should prove of great synthetic utility in preparation of substituted diazines. / Ph. D.

The rates of reaction of pulverized samples (100-200 mesh) of blaubleibender covellite and covellite with 10⁻³ m ferric iron in a pH 2 solution were determined at 25, 35, and 50°C. Ferrous and cupric ion concentrations of the run solutions suggest that parallel reactions oxidized the sulfur to either elemental sulfur or to sulfate. The reaction that produces elemental sulfur is by far the fastest. The disappearance of ferric iron follows a first-order rate law which is a combination of the two first-order reactions: -dm_Fe3+/dt = (k₁ + k₂) (A/M) m_Fe3+ where m_Fe3+ is the molal concentration of uncomplexed ferric iron, k₁ and k₂ are the rate constants and A/M is the ratio of the surface area of the reacting solid to the mass of the solution. At 25°C the measured rate constants are 7.14 x 10⁻⁵ ± 1% sec⁻¹ for blaubleibender covellite and 9.4 x 10⁻⁴ ± 1% sec⁻¹ for covellite indicating that blaubleibender covellite reacts almost an order of magnitude faster than stoichiometric covellite under these conditions. However, the activation energies for these reactions, over the temperature interval 25 to 50°C, are the same, within the range of the reported error: 51.8 ± 6.2 kJ mol⁻¹ for blaubleibender covellite and 58.29 ± -13. 7 kJ mol⁻¹ for covellite. This suggests that the rate limiting step for both reactions is the same. The relatively high activation energies indicate surface reactions control the rate of oxidation at these temperatures. / Master of Science