The goal of this study was to provide a link between the family-supportive benefits offered by an employer, and the work-family conflict experienced by that organization's employees. In order for employee outcomes such as job satisfaction to remain high, the work-family conflict experienced by the employee needs to remain low. One way to possibly lower the amount of work-family conflict experienced is to offer family-supportive benefits.

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

abstract / Japanese Studies / Doctoral / Doctor of Philosophy

Highly dispersed gold nanoparticles on metal oxide surfaces have recently been reported to exhibit high catalytic activity for low-temperature carbon monoxide oxidation. Amongst the metal oxides, titanium dioxide, more often the commercial form Degussa P25, has been the most studied support for gold as a catalyst for CO oxidation because it yields some of the most active and stable catalysts. Physical and chemical modification of catalysts supports has been shown to affect their catalytic properties. In this research, modified gold supported catalysts have been prepared, characterized and tested for CO oxidation. Their properties have been compared with those of the unmodified catalysts. Catalysts containing1wt% Au supported on MxOy and TiO2/MxOy mixed oxide (M = Zn, Mg, Ni, Fe, Cr, Cu, Mn and Co; TiO2:MxOy mole ratio of 5:1; TiO2 = Degussa P25) were prepared by the single step borohydride reduction method and it was found that TiO2 gave the most superior activity as support for gold for CO oxidation, followed by TiO2/MxOy and the corresponding MxOy. The specific activities for CO oxidation of Au/TiO2 catalysts per unit of prepared in the range 0.05 to 1 wt% of Au indicates that for catalysts prepared by deposition precipitation, there is a significant decrease in specific activities with an increase with gold loading. For the single step borohydride reduction procedure, specific activities decrease less significantly with increasing gold content, implying that for economic and practical reasons, it would be advantageous to prepare gold catalysts with low gold loadings. Cyanide leaching of 1 wt% Au/TiO2 catalysts at different Au:CN- ratios, to selectively remove some of the gold in the catalysts, shows the activity per unit mass of gold to increases as more gold is removed from the catalyst. This is consistent with the idea that gold exists in more than one oxidation state in the systems and a significant fraction of the gold present in the catalysts do not contribute to catalytic activity. A number of anions and cations have been incorporated into TiO2 as support for gold catalysts and also into as-prepared Au/TiO2 catalysts at levels ranging from 0.05 mol% to 2.5 mol% with respect to the support. The activities of the catalysts for CO oxidation reveal that at the highest concentration levels of the ions, in all cases, a decrease in activity compared with unmodified Au/TiO2 is observed. However, addition of 0.05 to 0.4 mol% of the ions with respect to the support, prior to gold addition, in most cases, resulted in activity enhancement which increased with a decrease in the ion content. Similar addition of 0.05 to 0.4 mol% of the ions with respect to TiO2 to Au/TiO2 resulted in a decrease in activity. Attempts to understand the origins of these effects show that there is a degree of chemical interaction between the added ions and gold.

The ability to collaborate has been identified as an essential learning outcome for the 21st century. However, if group members lack the skills, abilities, and attitudes to work in a team, these groups may work inefficiently or fail to achieve what they set out to do. To achieve success, group members need to engage in productive regulatory processes to manage cognitions, behaviors, motivation, and emotions as needed to attain desired outcomes. One area of regulation that has been underemphasized in collaborative contexts is the regulation of emotions. Therefore, the purpose of this multi-paper dissertation was to examine the emotional experiences of undergraduate students working collaboratively on two online time-limited problem-solving tasks. Using a regulation of learning framework, the research unfolded over four studies drawing from a variety of data sources and building upon one another to explore the socio-emotional aspect of online collaboration. Study 1 (Webster & Hadwin, 2018) provides an overview of students’ emotions and plans for emotion regulation, self-reported during two collaborative tasks, offering an in-the-moment picture of how students feel and how they respond to those feelings. Study 2 (Bakhtiar, Webster, & Hadwin, 2018) consisted of a comparative case study to examine differences in regulation and socio-emotional interactions between two groups with contrasting socio-emotional climates. Findings revealed differences between these groups in terms of planning and preparation; therefore, the final two studies examined emotions and emotion regulation strategies reported during groupwork under different levels of planning and preparation at the individual or group level. Study 3 (Webster & Hadwin, 2019) documented the types of strategies students recalled using individually and as a group to regulate a salient emotion during collaboration and compared strategies between groups who were given different types of collaborative planning support. Finally, Study 4 (Webster, Davis, & Hadwin, 2019) compared emotions, emotion regulation strategies, and evaluations of strategy effectiveness for a purposeful sample of students who were well-prepared versus underprepared for the first of two collaborative working sessions. Four overarching factors emerged from this research as important for productive emotion regulation in online collaboration: (a) planning and preparation, (b) regulating both negative and positive emotions, (c) regulating at both individual and group levels, and (d) providing support for selecting and enacting helpful strategies. With further research, tools and interventions can be improved and utilized to support students to productively regulate in collaborative groups. / Graduate

Due to the escalating challenge of antibiotic resistance in bacteria over the past several decades, interest in the identification and development of antibiotic alternatives has intensified. Antimicrobial peptides (AMPs), which serve as part of the innate immune systems of most eukaryotic organisms, are being researched extensively as potential alternatives. However, the mechanism behind their bactericidal capabilities is not well understood. Previous studies have suggested that AMPs may first attach to the cell membranes, leading to pore formation caused by peptide insertion, lipid removal in the form of peptide-lipid aggregates, or a combination of both mechanisms. In addition to the lack of mechanistic knowledge, a significant hurdle in AMP-based drug development is their potential cytotoxicity to mammalian cells. Understanding AMP interactions with eukaryotic model membranes would allow therapeutics to be tailored for preferential action toward specific classes of bacterial membranes. In this study, we developed novel methods of quartz crystal microbalance with dissipation monitoring (QCM-D) data analysis to determine the fundamental mechanism of action between eukaryotic and bacterial membrane mimics and select membrane-active AMPs. A new technique for creating supported membranes composed entirely of anionic lipids was developed to model Gram-positive bacterial membranes. Atomic force microscopy (AFM) imaging was also used to capture the progression of AMP-induced changes in supported lipid membranes over time and to validate our method of QCM-D analysis. QCM-D and AFM were used to investigate the molecular-scale interactions of four peptides, alamethicin, chrysophsin-3, sheep myeloid antimicrobial peptide (SMAP-29) and indolicidin, with a supported zwitterionic membrane, which served as a model for eukaryotic cell membranes. Since established methods of QCM-D analysis were not sufficient to provide information about these interaction mechanisms, we developed a novel method of using QCM-D overtones to probe molecular events occurring within supported lipid membranes. Also, most previous studies that have used AFM imaging to investigate AMP-membrane interactions have been inconclusive due to AFM limitations and poor image quality. We were able to capture high-resolution AFM images that clearly show the progression of AMP-induced defects in the membrane. Each AMP produced a unique QCM-D signature that clearly distinguished their mechanism of action and provided information on peptide addition to and lipid removal from the membrane. Alamethicin, an alpha-helical peptide, predominantly demonstrated a pore formation mechanism. Chrysophsin-3 and SMAP-29, which are also alpha-helical peptides of varied lengths, inserted into the membrane and adsorbed to the membrane surface. Indolicidin, a shorter peptide that forms a folded, boat-shaped structure, was shown to adsorb and partially insert into the membrane. An investigation of rates at which the peptide actions were initiated revealed that the highest initial interaction rate was demonstrated by SMAP-29, the most cationic peptide in this study. The mechanistic variations in peptide action were related to their fundamental structural properties including length, net charge, hydrophobicity, hydrophobic moment, accessible surface area and the probability of alpha-helical secondary structures. Due to the charges associated with anionic lipids, previous studies have not been successful in forming consistent anionic supported lipid membranes, which were required to mimic Gram-positive bacterial membranes. We developed a new protocol for forming anionic supported lipid membranes and supported vesicle films using a vesicle fusion process. Chrysophsin-3 was shown to favor insertion into the anionic lipid bilayer and did not adsorb to the surface as it did with zwitterionic membranes. When introduced to supported anionic vesicle films, chrysophsin-3 caused some vesicles to rupture, likely through lipid membrane disruption. This study demonstrated that molecular-level interactions between antimicrobial peptides and model cell membranes are largely determined by peptide structure, peptide concentration, and membrane lipid composition. Novel techniques for analyzing QCM-D overtone data were also developed, which could enable the extraction of more molecular orientation and interaction dynamics information from other QCM-D studies. A new method of forming supported anionic membranes was also designed, which may be used to further investigate the behavior of bacterial membranes in future studies. Insight into AMP-membrane interactions and development of AMP structure-activity relationships will facilitate the selection and design of more efficient AMPs for use in therapeutics that could impact the lives of millions of people per year who are threatened by antibiotic-resistant organisms.

Supported lipid bilayers (SLBs) are one of the most common model membranes used in the field of cell membrane biology as they provide a well-defined model membrane platform for determination of molecular-level interactions between different biomolecules (e.g. proteins, peptides) and lipid membrane. Compared to model organisms, the use of SLB is preferable since it mimics cell plasma membrane in a very simple and well-controlled way. Therefore, molecular structure of membrane and experimental conditions (e.g. solution chemistry, temperature, and pH) can be easily adjusted to the required conditions of any systematic research. In addition, SLBs are typically easy to form, cheap and very reproducible and they are compatible with different surface characterization techniques, such as quartz crystal microbalance with dissipation (QCM-D), ellipsometry and atomic force microscopy (AFM). This study demonstrates that QCM-D analysis of SLBs serve as powerful tool to investigate and characterize the mechanisms of interactions between lipid membrane and gold nanoparticles (NPs), environmentally relevant polymers, and disease-inducing peptides. Due to many critical applications of gold NPs in drug delivery and diagnostics, understanding of membrane-NP interactions is crucial especially for determination of NPs cytotoxicity. In this study we focus on membrane disruption as one of the different mechanisms by which metal NPs induce cytotoxicity. The use of SLB is beneficial for this goal as it elucidates the unique mechanism of membrane disruption without interference of other mechanisms taking place simultaneously in biological cells. For NP-membrane interaction studies, a SLB composed of L-α-phosphatidylcholine (egg PC) was formed on a SiO2-coated crystal and QCM-D analysis was performed to obtain information about mass and viscoelastic changes of SLB resulting from interactions with gold NPs. For better understanding of the mechanisms of NP-membrane interactions, we systematically changed the NPs properties and the experimental conditions. In order to understand the effect of NP size, gold NPs with diameters of 2,5,10, and 40 nm were tested and compared to each other. NPs were tested in their citric acid-stabilized state as well as in the presence of poly (methacrylic acid) (PMAA), representing an organic coating that could become associated with NPs in the environment. The results indicated that when dissolved in water, gold NPs with the dimeters of 2, 5, 10, and 40 nm did not perturb the membrane, but in the presence of environmentally relevant polymer, the larger nanoparticles were found to disrupt the membrane. In order to elucidate the effect of surface chemistry, 10 nm - gold NPs with various functionalizations (i.e. anionic, cationic and non-ionic ligands) were tested. Control experiments were designed to test the effect of NPs in the absence of humic substances which means the NPs were dissolved in water. In these cases, regardless of the type of NP functionalization, no substantial bilayer mass changes were observed. This suggests that the charge and chemistry of the ligands had a minor effect on NP-membrane interactions. Furthermore, in both the control and humic acid experiments, there were small dissipation changes (less than 1 unit) indicating that the overall membrane structure was not perturbed. In order to mimic environmentally-relevant conditions, mass and viscoelasticity of SLB was characterized in the presence of four different natural polymers, also known as natural organic materials (NOMs): Fulvic and humic acids extracted from Suwannee River (SRFA and SRHA), which had relatively lower molecular weights and a commercial humic acid (HA) and the humic acid extracted from Elliott soil (ESHA) with higher molecular weight. The results showed that NOMs with lower molecular weights, adsorbed to the bilayer, while higher molecular weight components, did not induce any changes to the bilayers. In addition, the NPs in SRFA and SRHA increased the mass of the bilayer by 20-30 ng, while the NPs in HA and ESHA changed the mass of the bilayer by < 10 ng. It was concluded that the presence of humic substances as well as their physical and chemical properties exert a direct impact on the interactions between cell membrane and the nanoparticles. In addition to the field of NP toxicity, SLBs play a pivotal role in the field of neurodegenerative diseases, such as Alzheimer’s disease (AD), in which the pathological cascade of events starts from interactions of a misfolded peptide with cell membrane. In this thesis, we confirm the validity of QCM-D analysis of SLB as an important platform for investigation of amyloid β (the peptide associated with AD) interactions with lipid membrane. Adsorption of Aβ peptide to cell membrane is known to take place on the so-called “lipid raftâ€� which are membrane microdomains enriched with cholesterol, sphingomyelin and ganglioside. The formation of SLBs containing lipid rafts is not only important for the field of AD research, but also it is important for other in vitro studies of cell biology as the lipid rafts are responsible for a variety of biological functions such as association of some membrane proteins and cellular signaling. However, the presence of lipid raft components such as sphingomyelin and cholesterol makes the formation of the bilayer more challenging which leads to adsorption of intact vesicles on the substrate without formation of the bilayer. In this study, the formation of lipid bilayer composed of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl- sn-glycero-3-phospho-L-serine (DOPS), cholesterol (Chol), sphingomyelin (SM), and ganglioside (GM) was investigated using QCM-D. A challenge was that the raft-containing vesicles remained intact on the SiO2 crystal. Therefore, different experimental conditions were tested to induce vesicle fusion, such as pH, temperature, osmotic pressure, and vesicle size. The key parameter in forming the bilayer was found to be applying osmotic pressure to the vesicles by having the vesicles exterior concentration of NaCl higher than interior concentration. When this concentration gradient was applied to the vesicles before flowing them on the substrate, vesicle rupture was favored and formation of a complete bilayer could occur. Here, we report the effects of each tested variable on the adsorption and fusion of the raft-containing vesicles, and the results are discussed based on the mechanisms of vesicle-vesicle and vesicle-substrate interactions.After developing the robust method for formation of SLB with lipid rafts, we used that as a template to characterize the mechanism of interactions between Aβ peptide and cell membrane which leads to onset of AD. The mechanism of Aβ toxicity leading to AD has not fully discovered yet, due to the complexity of the process including several steps of Aβ peptide adsorption on membrane, conformational change from disordered in solution to a membrane-bound α-helix structure and then formation of β-sheet aggregates that serve as fibrillation seeds. In this study, we showed that QCM-D technique as a promising tool to conduct systematic studies on the mechanism of interactions between Aβ peptide with lipid membrane. To our knowledge, this was the first time QCM-D was utilized for characterization of Aβ fibrillation starting from monomer states until formation of mature fibrils. The data indicated that peptide-membrane interactions follow a two-step kinetic pathway starting with the adsorption of small (low-n) oligomers until covering all the adsorption sites on the surface. In the second step, the membrane structure is destabilized as the result of interaction with oligomers which leads to lipid loss from the surface. Consistency of the results with the data obtained via other techniques substantiates QCM-D technique as a robust approach to answer the remaining unanswered questions in the field of Alzheimer’s disease.

Almost 25 years ago, Clawson, Bostrom, and Anson (1993) drew attention to the fact that the ability to facilitate diverse human and technological interactions will be one of the most essential skills for leading and contributing to all levels of the organization in the future (p. 547). Today, there is an increased interest in studying facilitated meetings, wherein facilitation is most commonly understood as the process of helping groups work effectively to accomplish shared outcomes. Nevertheless, little of the existing research has provided empirically-grounded insights into the practice of facilitation. This thesis aims to close this gap by means of providing a detailed analysis of how facilitators go about doing facilitation work in facilitated computer-supported workplace meetings. The data comprise 53 hours of audio- and video-recorded multi-party interactions among facilitator(s) and participants, occurring during facilitated meetings in a business setting. The data were analysed using conversation analysis to examine the talk and embodied conduct of facilitators and meeting participants, as these unfold sequentially. The first analytic chapter reveals the macro-organization of the facilitated meetings, and it contrasts the practice view with the theoretical approach towards the organization of the facilitated meetings. The second analytic chapter investigates the interactional practices used by the facilitators to unpack participation that has already been elicited, captured, and displayed graphically on the public screen via the use of technology. In the third analytic chapter, I explore how the facilitators use computer software to build visual representations of the participants contributions. In the final analytic chapter, I investigate the practices of decision-making in meeting settings with multiple participants. Overall, this thesis makes innovative contributions to our understanding of the practice of facilitated computer-supported workplace meetings. It challenges existing literature on facilitation by finding that facilitators can orchestrate participant input, questioning the facilitator s role as content-neutral , as proposed by leading practitioners in the field of facilitation (e.g., Kaner et al., 2014). At the same time, it shows how the manipulation of computer software is an accountable action and how the decision-making process occasions or constrains the production of alignment between participant(s) and facilitator(s). The thesis also contributes to conversation analytic research on questioning, as well as the action of unpacking participation. I show that the notion that open-ended questions better elicit participation than interrogatives is generally not supported empirically, at least in this context. The thesis contributes to existing literature on multi-party meeting interaction, showing how the departure from the canonical next-speaker selection technique which involves the use of address terms and address positions in an utterance takes place. Further, it enhances our understanding of how computer software constrains and/or affords progressivity in interaction. In this sense, I enhance our understanding of the concept of agency of artefacts. Finally, I contribute to knowledge on group decision-making, an under-researched yet core activity in facilitated and other types of meetings. Here, I contribute to the body of work on the interplay between deontics and epistemics in interaction. This thesis shows the applicability of conversation analysis to the study of facilitation. By analysing talk and embodied conduct, communicative practices for accomplishing successful facilitated meetings are revealed and these should be of core interest to both professional and novice facilitators.

Diminishing petroleum reserves and environmental considerations have strengthened the demand for developing renewable fuel technologies. One alternative is deoxygenating plant oils, animal fats, and waste lipid streams to fuel-like hydrocarbons. These fuels offer a drop-in replacement to petroleum products while potentially becoming carbon neutral, satisfying both fuel and environmental concerns. This fuel is obtained through catalytic deoxygenation via either hydrodeoxygenation (HDO) or decarboxylation/ decarbonylation (deCOx). HDO requires problematic sulfided catalysts and extreme hydrogen pressures to convert lipids to fuel-like hydrocarbons. Therefore, this work focuses on the deCOx pathway, where hydrogen is not required for deoxygenation to take place. Generally, other authors use Pd or Pt as the active metals for deCOx; however, their cost can be industrially prohibitive. Recently, inexpensive Ni catalysts have shown comparable catalytic deCOx activity to Pd and Pt, albeit significant catalyst deactivation and catalytic cracking to undesirable products remain problematic. Therefore, this work aims to improve the activity, selectivity, and recyclability of supported Ni catalysts for the deCOx of lipids. Cu, Sn, and minimal amount of Pt were investigated as secondary promoter metals for Ni catalysts for deCOx. Deoxygenation of waste lipids such as brown grease and yellow grease was also accomplished in an industrially relevant fixed bed reactor.