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<p>This thesis places Hebrew Christianity and Messianic Judaism on the church-sect continuum devised by Rodney Stark and William Sims Bainbridge (1979, 1980). According to an axis indicating low to high tension with the environment, Hebrew Christianity is placed on the para-church node, between the denomination and the sect. Messianic Judaism, in general, is placed on the high tension, sect end of the continuum. It is recognized, however, that individual organizations which comprise the movements may vary widely in their relationships to t he environment. Since the organizations as well as the movements may oscillate on the church-sect continuum, social movement propositions are introduced that can explain how and under what conditions these changes occur. A study of one Hebrew Christian organization, which contains both a low and a high tension group, shows, on the one hand, that a single organization can occupy two different . points on the church-sect continuum simultaneously. It shows, on the other hand, that this is made possible through the skillful use of leadership functions, which in turn is buttressed by the symbolic value of a Jewish leader. Finally, the peculiar situation of the HFOI is seen as reflective of the larger trends in the Hebrew Christian and Messianic Jewish movements, in general, and the different "agendas" of the Jewish and the Gentile followers, in particular.</p> / Doctor of Philosophy (PhD)

An overexposure to ultraviolet radiation can cause sunburn and some forms of skin cancer. UV light causes many different photoproducts. The cys-syn cyclobutylpyrimidine dimer (CPD) is the major photoproduct upon UV irradiation. DNA photolyase (PL) is a light-driven flavoprotein that repairs CPD in UV-damaged DNA. This repair process occurs in the presence of blue light through ultrafast photo-induced electron transfer from reduced anionic flavin adenine dinucleotide (FADH¯) to the CPD by an unknown mechanism. Since the excited state flavin transfers an electron to repair the damaged DNA, it is of utmost importance that we understand better the excited state properties of the flavins. In this work the excited state electronic properties of all three-oxidation states of flavin: oxidized form (FAD), semiquinone radical form (FADH•) and reduced anionic form (FADH¯) were studied using Stark spectroscopy and complimented by time dependent density functional theory (TD-DFT) calculations. These results are presented and discussed in Chapter 3 and 4. The difference dipole moments (Δμ) and the difference polarizabilities (Tr(Δα01)) were experimentally determined for first two lowest optically accessible states. The results are discussed in the context of photoreduction of flavins in wider class of flavoprotein blue light photoreceptors and catalytic electron transfer process in DNA repair. In the later part of this thesis (Chapters 5 and 6) the excited state electronic properties of monomeric 2-Aminopurine (2AP), 8-Vinyladenine 8VA were presented. These 8VA, 2AP are examples of fluorescent nucleotide analogues of adenine that can be incorporated into DNA with little perturbation of the normal double-helical structure. The fluorescence of these analogues is quenched when incorporated in double-stranded DNA (dsDNA). The basic mechanism underlying the fluorescence quenching by base stacking of 2AP and 8VA are is not well understood, and thus exploring the excited state electronic structures of these bases is an important first step. We have explored the excited state properties of 2AP and 8VA in frozen LiCl and ethanol solutions using Stark spectroscopy. High-level ab initio and TD-DFT calculations were performed to compliment the experimental results. / Chemistry

Mineral oxide/aqueous interfaces play an important role in the transport of water through aquafers and streams, erosion, the formation of beaches and river deltas, nuclear waste storage, the sequestration and filtration of small ions, and are widely used in industrial scale catalysis. Unlike metal or semiconductor electrodes, the surface charge resulting from the protonation or deprotonation of insulating mineral oxides is highly localized and heterogeneous in nature. While the unique acid/base chemistry associated with different mineral oxide surfaces leads to their wide variety of applications, the extent to which surface groups found on mineral oxides partake in acid/base chemistry is still controversial due to the difficulty associated with experimentally probing them. Surface specific spectroscopic techniques, such as vibrational Sum Frequency Generation (vSFG), provide an opportunity to investigate how the surface architecture and corresponding chemical nature of various mineral oxide surfaces orient the interfacial solvent at a variety of solvent compositions and surface charges. Although vSFG has been used as a tool to measure the orientation and composition of interfacial O-H species originating from the surface and solvent for many mineral oxide/aqueous interfaces since the late 1990’s, controversy still exists in the assignment of vSFG spectra in the O-H stretching region of SiO2, Al2O3, CaF2, and TiO2/aqueous interfaces. The first section of this dissertation focuses on how the nonlinear optics and computational community’s understanding of the structure associated with mineral oxide/aqueous interfaces has evolved and where it stands now. Of particular interest is how the addition of electrolyte and variation of bulk pH allow modulation of the depth of the interfacial region and surface charge. Electrolyte solutions can vary the length of the interface by screening interfacial charges through non-specific adsorption at the interface, or generating surface charge if accumulation is facilitated by specific adsorption. The specific interaction of small ions with mineral oxide surfaces is relevant in geochemistry and filtration technology, and can also aid in prediction of contaminant mobility in ground water systems. Chapters two and three discuss the theory and application of vSFG, and the experimental setup used to capture vSFG spectra in this work, respectively. The fourth chapter investigates how monovalent or divalent cations accumulate at alpha-Al2O3(0001)/H2O interfaces and reorganize the interfacial solvent structure. The reactivity of these interfaces is strongly impacted by the presence of ions. Thus, it is critical to understand how ions alter the interfacial environment. This is achieved by measuring the changes in the structure and vibrational dynamics of interfacial water induced by the presence of ions in close vicinity to the mineral surface. The alpha-Al2O3(0001) surface represents a flexible platform to study the effect of ions on interfacial aqueous environments at positive, neutral and negative surface charge. Using vibrational sum frequency generation (vSFG) in the frequency and time domain, we investigate how monovalent and divalent cations affect the hydrogen bonding environment of the first few layers of interfacial water next to an alpha-Al2O3(0001) surface. Our results indicate that monovalent cations, such as Li+, Na+, K+, and Cs+, appear to have lower adsorption affinities for the interface compared to Ca2+, Sr2+, and Ba2+. This leads to an interfacial region that is structured in a cation valence dependent manner. Time resolved vSFG measurements reveal that the O-H vibrational lifetime (T1) of interfacial species at pH 10 conditions in the presence of NaCl and BaCl2 remains similar, but restructuring of the surface seen in steady state vSFG is manifested in the degree to which strongly hydrogen bonded species recover to their original populations post excitation. By tracking the accumulation of ions at the interface via the vSFG response, we can characterize the unique surface arrangements of interfacial water molecules induced by a range of monovalent and divalent cations at the alpha-Al2O3(0001)/water interface. In the fifth chapter the Stark active C ≡ N stretch of potassium thiocyanate is used as a molecular probe of interfacial electrostatic potential at the alpha-Al2O3(0001)/H2O interface. We confirm the presence of the thiocyanate ion in the interfacial region via reorganization of surface waters in the O-H stretching region. Changes in electrostatic potential are then tracked via Stark shifts of the vibrational frequency of the C ≡ N stretch. Our vSFG measurements show that we can simultaneously measure the SFG response of SCN- ions experiencing charged and neutral surface sites and assign a local potential of + 308 mV and -154 mV to positively and negatively charged aluminol groups, respectively. Thiocyanate anions at charged surface sites adopt similar relative orientations independent of surface charge, but adopt an opposite orientation at neutral surface sites. MD-DFT simulations of SCN- near the neutral alpha-Al2O3(0001)//H2O interface show that the vSFG response in the C ≡ N stretch region originates from a SCN-H-O-Al complex, suggesting the surface site specificity of these experiments. By tracking how this molecular probe responds to local surface charges we offer insight into the local electrostatic potential at neutral and charged surface aluminol groups. Chapter six investigates the vibrational dynamics of potassium thiocyanate at the alumina/water interface. Here, we leverage the sensitivity of the C ≡ N stretch vibrational lifetime of potassium thiocyanate to measure the local electrostatic potential at the alpha-Al2O3(0001)/H2O interface. To accomplish this, KSCN was investigated using free induction decay vSFG (FID-vSFG) and time resolved pump probe (TR-vSFG) measurements, which measure the total dephasing time and vibrational lifetime of the excited C ≡ N stretch, respectively. Our FID-vSFG spectra suggest that at all surface charges the total dephasing time of SCN- is on the order of ~300-600 fs. TR-vSFG characterizations of potassium thiocyanate report the vibrational lifetime of the excited C ≡ N stretch between ~0.5-2 ps. TR-vSFG measurements show two distinct vibrational relaxation rates, which are assigned the CN stretch and the HOH bend plus libration combination band of interfacial water. The variation in the T1 lifetime of the CN stretch with bulk pH show that changes in the SCN- net orientation measured using steady-state vSFG can be correlated to the vibrational dynamics in the interfacial region. The energy transfer to the bend plus libration combination band of water is also sensitive to the surface charge, as the lifetime of this species becomes shorter as the bulk pH is increased. Lastly, in chapter seven this thesis is summarized, and future directions of the experiments presented here are discussed. / Chemistry

The excited state electronic structures of several biologically important chromophores were studied by Stark spectroscopy. The extent of charge redistribution upon excitation to the lowest excited states of the oxidized and semiquinone forms of flavin adenine dinucleotide (FAD) bound to the light activated DNA repair enzyme DNA photolyase have been studied previously by this technique. This work focuses on the catalytically active form, the two-electron reduced anion. To facilitate analysis of this experiment, the Stark spectra of a simple flavin derivative that is soluble in organic solvents was measured. The results of the analysis of these data are in agreement with previously a published linear dichroism experiment that found the absorption spectrum of flavins in this redox state arises from two distinct electonic transitions in the visible/near-ultraviolet spectral range, a fact that has not been incorporated into the analysis of many ultrafast spectroscopic experiments of reduced anionic flavins/flavoproteins. The difference dipole moment of the second, more intense, transition was found to be about twice as large as that of the lowest energy transition. With the aid of ab initio calculations, the directions of these dipole moments in the molecular frame were assigned. For both transitions, it was found that negative charge density is shifted toward the xylene ring of the flavin upon excitation. Another important consideration for the correct analysis of the photolyase spectra is the possibility of contamination by small amounts of the antenna chromophore, which also has absorption intensity in the near-ultraviolet region. We chose to study the cofactor for E. coli photolyase, 5,10-methenyltetrahydrofolate, and its photodecomposition product, 5,10-methylenetetrahydrofolate. The difference dipole moments for the lowest energy transitions of both of these chromophores were found to be quite large, ranging from 9-12 D fc and lying primarily along the transition dipole moment. Additionally, the difference polarizability of both chromophores was large, on the order of 200-300 &Aring;3 fc2 . The Stark spectra of reduced anionic FAD in photolyase agrees well with the findings of the experiments on flavin in organic solvent; the magnitude of the difference dipole moments in both cases match within experimental error. While the direction of the difference dipole moment for the lowest transition is also the same in both cases, that of the second transition is changed in the protein matrix. The assignment of these vectors in the molecular frame shows that the two dipole moments are coincident for the cofactor bound to photolyase. This finding, where electron density is shifted toward the point of the flavin ring closes to the DNA lesion bound to the enzyme, is strong evidence that direct electron transfer takes place from the isoalloxazine ring of FAD to the DNA substrate in the catalytic cycle. The usefulness of Stark spectroscopy in investigating photoinduced charge redistribution was also shown for the donor-&pi;-acceptor flavin dyad, azobenzylflavin (ABFL). The difference dipole moment was found to be 22 D, an approximately three-fold increase from the largest difference dipole moment found in naturally occurring flavins. This extensive charge redistribution corresponds to a large hyperpolarizability of the chromophore that suggests that ABFL may be useful in nonlinear optical applications. Transient absorption was used to supplement these experiments by monitoring the decay kinetics of ABFL after excitation. It was found that ABFL undergoes ultrafast charge recombination within 6 ps after excitation, leading to depopulation of the charge separated state before useful work can be performed for applications requiring electron transfer. These studies provide the ground work for rational design of other ABFL-like derivatives for use in a variety of applications. / Chemistry

Heterogeneous reactions between gas-phase oxidants and particulate-phase organic compounds impact many important atmospheric chemical processes. For example, little is known about the reaction dynamics of gaseous oxidants with organic compounds found in the atmosphere. The first step of the reaction between gaseous ozone and solid pentacene was investigated using Reflection Absorption Infrared Spectroscopy (RAIRS). Ozone was found to add to pentacene non-selectively and form a range of products after heavy ozone exposure. The rate limiting step had an activation energy of 17 kJ/mol, which is consistent with the findings of previous ozone oxidation studies for the cleavage of a carbon-carbon double bond. Unfortunately the products could not be used to distinguish between probable reaction mechanisms. Hydroxyl radicals (•OH) play a major role processing atmospheric hydrocarbons. Due to their short lifetimes, not much is known about the dynamics of the first steps of •OH reactions. To investigate these reactions, a rotational state-selector was constructed to filter a molecular beam of •OH for reaction dynamics investigations with organic surfaces. The rotational state-selector was designed to leverage the linear Stark effect to pass only suitable molecules in a particular rotational state and block the flow of any other atoms, molecules and ions in a molecular beam. The state-selector was validated and used to positively deflect molecular beams of methyl iodide and D₂O via the linear Stark effect. Future studies with the rotational state-selector will investigate the initial steps of •OH reactions with solid organic compounds. / Master of Science

Le défi proposé était d'obtenir une mesure en direct du voltage présent sur une membrane bactérienne. D'abord, nous avons construit et inséré dans nos cellules E. coli un plasmide contenant le canal ionique dépendant du voltage NaChBac (Bacillus halodurans). ha, mesure d'une discontinuité dans le courant (au voltage bien documenté correspondant à l'ouverture du canal) devait permettre de calibrer la tension appliquée. Malheureusement, la présence de courants de fuite a masqué ce signal. Parallèlement, nous avons marqué la membrane avec l'ANNINE-6plus, une sonde fluorescente potentiométrique soluble dans l'eau à large décalage Stark. La fluorescence mesurée variait de ~1,5 % pour un changement de 150 mV sur la membrane. À notre connaissance, il s'agit des premières mesures optiques en temps réel du voltage sur une membrane bactérienne, bien qu'il faille en améliorer le signal et la robustesse.