A major challenge to any “solvent-based” bitumen extraction technology is the removal of suspended fine solids from the hydrocarbon medium (i.e. diluted bitumen). To address this problem, we examined how colloidal solids could be made to aggregate in a hydrocarbon medium and thus be separated by gravity settling. The model solids were micron-sized “bitumen-treated” silica particles; the oil phase was bitumen diluted in an organic solvent of variable aromatic content. On the macroscopic scale, the experiments involved quantifying the settling rates of the particles as the aromatic content of the solvent was varied. Our results showed the existence of an optimal (non-zero) aromatic content at which the solids settling rate was the highest. On the microscopic scale, adhesive forces between individual glass spheres were directly measured using the microcantilever technique (again in non-aqueous media). It was demonstrated that, in addition to being captured by asphaltene networks, the suspended solids could also homo-flocculate — and thus form aggregates and be separated — in an alkane-diluted bitumen environment. / Chemical Engineering

There are approximately 10^14 bacteria belonging to nearly 1000 different species in the human gastrointestinal (GI) tract that co-exist with host cells. Within the GI tract, signaling molecules secreted by both eukaryotic and prokaryotic cells are abundant. Recent studies have shown that both bacteria and human cells recognize and respond to the signals from each other, presumably to gain a competitive advantage. The cross-recognition of signals is known as Inter-kingdom (IK) signaling and this phenomenon is considered to be important in the onset of infections in the GI tract. Of the eukaryotic signaling molecules present in the GI tract, the neuroendocrine hormone norepinephrine (NE) is considered to be important in the context of infections as NE is produced at very high concentration in the intestine under post traumatic stress, is known to increase bacterial virulence and infection, and has also been shown to be a potent chemoattractant for GI tract pathogens such as enterohemorrhagic E. coli (EHEC). The focus of this study is on elucidating the mechanisms underlying the recognition and chemotaxis of bacteria towards NE. While chemotaxis has been typically investigated in the context of bacteria moving towards a metabolizable source (e.g., amino acids), chemotaxis is potentially important in the onset of infections in the human GI tract. In this study we use a microfluidic plug assay to investigate the receptor and mechanism utilized by a model bacterium Escherichia coli in its chemotactic response to NE. A series mutant of E. coli RP437 strains of knockouts for four MCP-encoding genes was used in this study. The results from the microfluidic plug assay were then confirmed quantitatively by capillary assay. We have shown that Tsr receptor is necessary for chemotaxis of NE for E. coli RP437, and attraction of E. coli towards NE may require an additional receptor. Results from the priming experiments suggest that exposure to NE may result in the de novo expression of co-receptor(s) that are crucial to chemotaxis towards NE. The requirement for high cell density also suggests the possibility that NE per se may not be an attractant for E. coli, but could be a precursor that is modified into a chemoattractant by cells. These results are expected to further our understanding of bacterial chemotaxis and its role in bacterial colonization and infection of the human GI tract.

The present study examined the relationship between marital conflict, parenting conflict and emotional and behavioural problems in children aged 2 to 16 years. Additionally the psychometric properties of the Parent Problem Checklist (PPC; Dadds & Powell, 1991) were examined in sample of 200 parents sharing the role of parenting. The purpose of the present study was threefold: (1) to gain a measure of parenting conflict and children’s behavioural and emotional problems in a non-clinic referred community sample, (2) to examine the individual contribution of conflict specific to child-rearing to the prediction of child problems, and (3) to further validate the psychometric properties and examine the factor structure of the Parent Problem Checklist (PPC; Dadds & Powell, 1991). Findings support the hypothesis that parenting conflict influences children’s outcomes more than either general marital conflict or marital satisfaction. Analyses of the PPC show evidence of strong reliability and validity for the measure and factor analysis provided support for a two-factor structure. Implications for clinical practice and understanding the role of parenting conflict in the development of child difficulty are discussed.

Zugl.: Berlin, Freie Univ., Diss., 2007

Thesis (Ed. D.)--Teachers College, Columbia University, 1974. / Typescript; issued also on microfilm. Sponsor: Margaret Lindsey. Dissertation Committee: A. Harry Passow. Includes tables. Includes bibliographical references (leaves 146-156).

Thesis (D. Min.)--Trinity International University, 2003. / Abstract. Includes bibliographical references (leaves 163-169).

Thesis (S.T.M.)--Trinity Lutheran Seminary, Columbus, Ohio, 1992. / Includes bibliographical references (leaves 279-292).

Thesis (D. Min.)--Trinity International University, 2003. / Abstract. Includes bibliographical references (leaves 163-169).

Universiẗat, Diss., 2001--Jena.

Universiẗat, Diss., 2002--Kiel.