Single-molecule (SM) fluorescence spectroscopy has become a useful and important experimental approach for investigating the optical properties of chemical systems. In this thesis, four subprojects in the field of SM fluorescence spectroscopy are presented in which SM spectroscopy has provided invaluable experimental insight into the systems of interest.<p> In the first project, the photophysical properties of Calcium-Green 1 (CG-1), a calcium-ion indicator, were studied at both the ensemble and SM levels. CG-1 is non-fluorescent in the absence of Ca2+ and becomes strongly fluorescent when bound to Ca2+. In the ensemble measurements, the absorption and fluorescence spectra were collected under various Ca2+ concentrations. In addition, the fluorescence lifetime of CG-2 was also studied as a function of [Ca2+]. From SM measurements, the photobleaching time and fluorescence intensity distributions of CG-1 were studied both in the presence and in absence of Ca2+. The results were compared with those obtained for the dual-fluorophoric variant, Calcium-Green 2 (CG-2), whose photophysical properties have been investigated by previous researchers. The experimental results reveal that CG-1 can exist in two different forms: a highly-quenched form due to the occurrence of photoinduced electron transfer (PET) in the absence of Ca2+, and a strongly fluorescent form when bound to Ca2+.<p> The second project is a continuation of a previous study on CG-2. In the dual-chromophore CG-2 system, energy transfer between chromophores is controlled by the orientation and spatial separation between chromophores. Dual polarization fluorescence microscopy was used to determine the relative conformation of the two fluorophores in the emissive form of CG-2. Distributions of fluorescence polarization of individual CG-2 molecules were collected for both Ca2+-free and Ca2+-saturated conditions. The experimental polarization results were compared to those calculated from a simple geometric model based on randomly-orientated fluorescent dimers. The results show good agreement with previous calculations of the molecular conformation of CG-2. This indicates that the dual polarization imaging approach has significant potential as a general tool for characterizing chromophore orientation in coupled-fluorophore systems.<p> In the third project, Nile Red (NR), a solvatochromic lipid stain, was incorporated into phase separated Langmuir-Blodgett (LB) films composed of arachidic acid (AA) and perfluorotetradecanoic acid (PA). According to previous studies by atomic force microscopy (AFM), two types of separated domains are formed in the LB films: micron-sized hexagonal discontinuous domains that are exclusively comprised of AA, and the surrounding continuous domains which are enriched in PA. The photophysical properties of NR were characterized in the two physically and chemically distinct domains via bulk and SM fluorescence measurements. In addition to fluorescence microscopy, fluorescence confocal spectromicroscopy was also applied in the ensemble measurements to determine the spectral properties of NR in different sub-environments. Experimental results indicated that a small sub-population of dye molecules localize on the perfluorinated regions of the sample, but this sub-population is spectroscopically indistinguishable from that associated with the hydrogenated domains. Contrast in images was primarily due to preferential accumulation of the hydrophobic dye on the hydrophobic regions of the LB films.<p> In the final project, the fluorescence quenching behavior of a strongly fluorescent probe Alexa Fluor 514 (AF514) was investigated when it was covalently bound to gold metal protected clusters (AuMPC) with negligible plasmon bands. The fluorescence emission of the dye-AuMPCs system was characterized at different dye/Au MPC loading ratios with a combination of steady state and time-resolved ensemble spectroscopic measurements. It was found that the extent of fluorescence quenching in the system was small. After correction of inner filter effects, the results from bulk measurement demonstrate that the weak quenching is due to static quenching of the dye by the AuMPCs. SM measurements provided further support for the bulk measurements, with the fluorescence intensity of coupled AF514 molecules being comparable with that of unconjugated molecules. The photobleaching of the dye-AuMPC conjugates took place as a series of consecutive photobleaching events, without additional blinking dynamics within the time resolution of the experiment. These results suggest that the fluorophores on the AuMPCs are either entirely quenched, or remaining unquenched, as is consistent with the ensemble measurements.

The primary objective of the research project was to further develop a computer program modeling the hydrocracking of partially hydrogenated vacuum gas oil (HVGO), and to use the model to compare the theoretical product distribution to experimental data describing the product distribution of an industrial pilot reactor. The hydrocracking of HVGO on acid zeolites is effectively modeled utilizing a single-event kinetic approach developed by Froment and coworkers. The hydrocracking of HVGO can be described in terms of the fundamental reaction steps involving carbenium ions. Some 45 single-event rate parameters are used to dictate the rate of each single-event in the reaction network. The composition of the partially hydrogenated feed stock is detailed up to C33. Each component and lump is considered in terms of the elementary steps to generate a network of continuity equations and single-event rate parameters. A reactor model comprising this kinetic model can be used to simulate the isothermal and nonisothermal hydrocracking of a HVGO feed stock. The results are represented in terms of the yields of 241 lumps and components in the gas phase and 241 components and lumps in the liquid phase. The predicted yields of various commercial oil fractions and particular components are then compared to experimental data from an industrial pilot reactor to verify the accuracy of the model and the single-event rate parameters.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2002. / Field problem. Includes bibliographical references.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2004. / Includes bibliographical references.

Thesis (M.A.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vi, 61 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 43-46).

published_or_final_version / abstract / toc / Clinical Psychology / Master / Master of Social Sciences

Single index models are a special type of nonlinear regression model that are partially linear and play an important role in fields that employ multidimensional regression models. A wavelet series is thought of as a good approximation to any function in the space. There are two ways to represent the function: one in which all wavelet coefficients are used in the series, and another that allows for shrinkage rules. We propose posterior inference for the two wavelet representations of the function. To implement posterior inference, we define a hierarchial (mixture) prior model on the scaling(wavelet) coefficients. Since from the two representations a non-zero coefficient has information about the features of the function at a certain scale and location, a prior model for the coefficient should depend on its resolution level. In wavelet shrinkage rules we use "pseudo-priors" for a zero coefficient. In single index models a direction theta affects estimates of the function. Transforming theta to a spherical polar coordinate is a convenient way of imposing the constraint. The posterior distribution of the direction is unknown and we employ a Metropolis algorithm and an independence sampler, which require a proposal distribution. A normal distribution is proposed as the proposal distribution for the direction. We introduce ways to choose its mode (mean) using the independence sampler. For Monte Carlo simulations and real data we compare performances of the Metropolis algorithm and independence samplers for the direction and two functions: the cosine function is represented only by the smooth part in the wavelet series and the Doppler function is represented by both smooth and detail parts of the series.

This thesis examines the experiences of four single Canadian mothers of Jamaican heritage with respect to their children’s education. Four themes suggested in the literature—beliefs, practices, barriers, and supports—guided the research. The interviews with the mothers largely confirmed previous research in the field. As such, all the mothers believed that it was a shared responsibility between parents and teachers in supporting children’s education. The mothers’ practices included primarily at-home support and to a lesser extent at-school support but did not include strict discipline. The barriers most salient for these mothers were lack of time and resources. To help overcome these barriers, the mothers relied on domestic kin networks. From these findings, the thesis provides implications for both research and practice. / Thesis (Master, Education) -- Queen's University, 2007-09-14 17:35:40.569

Today the numbers of single people in Britain are mushrooming.  It is predicted that by 2020 they will form 40% of the total population.  This thesis seeks to discover why this is happening and to learn from the personal stories of single people to see how the Church may better minister to this vital section of society. After a brief historical survey of Irish monasticism and the impact of the Reformation on the nuclear industrial family, the thesis discusses the impact of the Victorian author and of the Hollywood film industry on traditional notions of romance and marriage.  These are contrasted sharply with prevailing contemporary post-modern views where relationships are often portrayed as temporal and vacuous. The thesis then enters the arena of real world research, exploring the issues of singleness with fifteen Christians - men and women of various ages, most of whom are single, although a number are (or were) married.  The primary focus of the interviewer is “What is it like being a single person in the Church today?”  The answers are wide-ranging and fascinating, touching on a number of important contemporary topics, such as loneliness, internet dating and sexuality.  Of particular note is the research suggesting that many church-going single people do not feel supported or understood by their faith communities.  In fact some find church to be one of the most isolating places of all. The author carefully weights up the evidence (including the biblical materials) and in the final chapter offers a strategic model for the contemporary Church.  Where there is a humble community which values friendship and encourages people to discover their own gifts to serve God, then <i>all</i> of God’s people - and not merely single people - are most likely to flourish.

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