Palladium and Nickel Catalyzed Olefin Isomerization and Polymerization

This work describes the preparation of palladium complexes supported by aminophosphinite pincer ligands and their reactivity in the presence of electrophilic reagents and olefins, respectively. An additional study into the oligomerization and polymerization of 5-ethylidene-2-norbornene (ENB) by cationic allyl Ni and Pd catalysts is also described. Chapter 2 investigates the challenges particular to palladium in the metalation of aminophosphinite pincer ligands. Three aminophosphinte ligands with a methoxy blocking group installed ortho to the phosphinite were prepared of varying amine substitution: a macrocycle-containing 15-aza-crown-5 ether, an acyclic bis(methoxy)diethylamine, and a diethylamine analogue containing no ether donor ligands. Neutral and cationic complexes of palladium based on these three different ligand scaffolds were prepared. Attempts to access Pd(IV) complexes based on the macrocycle-containing aminophosphinite scaffold are described, but no Pd(IV) intermediates were isolated or observed. Chapter 3 explores the reactivity of cationic macrocycle-containing and dialkylamine-containing with alkenes. The olefins 2,3-dimethyl-1-butene and allylbenzene were observed to be dimerized under catalytic conditions with macrocycle-containing cationic palladium complex and lithium salts. Only isomerization of 1-hexene was observed under the same catalytic conditions. A comparative study of the isomerization of 1-hexene by macrocycle-containing cationic palladium complex and dialkylamine-containing cationic palladium complex is described. This work provided the first comparative reactivity studies of macrocycle-containing aminophosphinite pincer catalysts and a dialkylamine-containing analogue with no hemilabile ether donors. Chapter 4 diverges from the chemistry of pincer-crown ether palladium complexes to study the oligomerization and polymerization of ENB by cationic allyl Ni and Pd catalysts. The relative activity of these catalysts towards the homopolymerization of ENB is substantially lower than towards unsubstituted norbornene (NB) polymerization. Added tertiary phosphine co-ligands in situ increases both Ni and Pd catalysts activity towards ENB homopolymerization. The oligomerization of ENB in the presence of these catalysts and chain transfer agents (CTAs) produces alpha-olefin terminated oligomers. These reactions proceed under mild conditions to predictably and selectively prepare ENB oligomers ca. 270 Da to high polymer (ca. 100,000 Da) with glass transition temperatures between -18 degrees Celsius and 200 degrees Celsius.Doctor of Philosoph

Understanding the risks of drinking water self-supplies from the perspective of rural people

Due to the potential for serious and widespread outbreaks of waterborne disease, managing the risk of microbiological contamination of drinking water is of particular importance. In New Zealand, drinking water quality and safety are regulated under the Health (Drinking Water) Amendment Act 2007. However, there remains a subset of the population for whom there is no such regulation of drinking water quality and safety. Rural households dependent on drinking water self-supplies, such as private wells, must take full responsibility for maintaining, monitoring and treating their own drinking water. Research suggests that these households often fail to engage in the actions recommended by public health authorities to protect drinking water quality and safety. To understand why this might be, this study set out to explore rural people’s perspectives on drinking water self-supplies in one rural location in New Zealand: Hinds, Mid Canterbury. Taking a social constructionist standpoint, I interviewed 15 residents responsible for and dependent on drinking water self-supplies in the rural Hinds area. Social constructionists argue that there is no single truth or reality. What is accepted as knowledge today is simply one of many ways of thinking which has been given the status of truth where others have not. Therefore, the social constructionist encourages society to question accepted knowledge and to consider why it came to be seen as the ‘truth’ in the first place. Through semi-structured in depth interviews, I focused on the Hinds residents’ experiences with their drinking water self-supplies, their understanding of the risks thereof, and their perceptions of drinking water quality testing. A sample of drinking water from each participating household was tested for Escherichia coli (E. coli) by an accredited laboratory. Three of the thirteen samples collected were found to contain E. coli. The residents were provided with their test results as a means of initiating discussion on drinking water quality testing. A thematic analysis of the data collected found that the rural Hinds residents I interviewed discussed water in a much wider context than simply their drinking water. They described how drinking water quality and quantity was influenced by other water resources in the area, drawing connections between groundwater, irrigation water and surface water bodies. To these water resources they applied a broad definition of water quality that extended beyond microbiological contamination to include health and the aesthetic attributes of water. The data analysis confirmed that my participants held sole responsibility for their drinking water self-supplies. However, drinking water was just one of a number of competing priorities for the rural Hinds residents I interviewed and, as such, drinking water quality and safety may benefit from a collaborative effort between rural residents and public health professionals. Rather than relying on scientific understandings of risk in promoting drinking water quality and safety, public health professionals may experience greater success in appealing to local values. These values include the protection of vulnerable populations, the preservation of resources for future generations, and the security of income and land values. Future research might expand on these understandings by seeking the views of non-farming rural residents in other areas of New Zealand, as well as those residents who have contracted a waterborne disease from their drinking water in the past, or are dependent on a different type of drinking water self-supply as their perspectives may differ from those of the participants in this study

The business of pantomime: regional productions 1865 to 1892

Whilst in recent years the study of nineteenth-century popular theatre and culture has expanded into the music hall, fairgrounds and 'minor' theatres, embracing melodrama and spectacle, the Victorian pantomime has attracted little attention. More especially, the widespread and dynamic productions of the English provincial theatres have been largely excluded in discussions that repeatedly focus on the London stage. My thesis is centred on the Theatres Royal of Nottingham and Birmingham, two towns sited in the English Midlands, but with markedly different population sizes, socioeconomic structures and national status. My argument, however, is not predicated on comparison but rather on siting the pantomimes within the very specific local contexts of each town. The relationship between the pantomime and the town engages with a notion of audience, identifiable through textual and promotional materials. The argument in my thesis moves from an overview of production styles at the two theatres to a specific analysis of the financing and promotion of the pantomime at Nottingham in the mid- 1860s. Using extant financial records, I have established how the pantomime was produced in times of local hardship, and how a production affected by low expenditure and failing revenue was promoted to its potential audiences. The emphases of advertising and the promotional techniques engaged by the theatre managements, together with those of the local newspapers also enable a reassessment of the role of the pantomime author. The traditional understanding of authorship as related to ownership of the text is reconsidered in relation to the role the pantomime author played in the promotion of the production, and his real and construed relationship to the theatre and town for which he was writing. Moreover, the available empirical evidence has served to foreground the pantomime text as an expression of local concerns and political interests that were particular to each town and displayed an acute awareness of issues of regional identity and status

Laboratory Headphone Studies of Human Response to Low-Amplitude Sonic Booms and Rattle Heard Indoors

Human response to sonic booms heard indoors is affected by the generation of contact-induced rattle noise. The annoyance caused by sonic boom-induced rattle noise was studied in a series of psychoacoustics tests. Stimuli were divided into three categories and presented in three different studies: isolated rattles at the same calculated Perceived Level (PL), sonic booms combined with rattles with the mixed sound at a single PL, and sonic booms combined with rattles with the mixed sound at three different PL. Subjects listened to sounds over headphones and were asked to report their annoyance. Annoyance to different rattles was shown to vary significantly according to rattle object size. In addition, the combination of low-amplitude sonic booms and rattles can be more annoying than the sonic boom alone. Correlations and regression analyses for the combined sonic boom and rattle sounds identified the Moore and Glasberg Stationary Loudness (MGSL) metric as a primary predictor of annoyance for the tested sounds. Multiple linear regression models were developed to describe annoyance to the tested sounds, and simplifications for applicability to a wider range of sounds are presented

Parental perceptions of technology and technology-focused parenting: Associations with youth screen time

In the present study we propose a model linking parental perceptions of technology to technology-related parenting strategies to youth screen time, and, finally, to internalizing and externalizing problem behaviors. Participants were 615 parents drawn from three community samples of families with children across three developmental stages: young childhood, middle childhood, and adolescence. The model was tested at each stage with the strongest support emerging in the young childhood sample. One component of parental perceptions of technology, perceived efficacy, was related to technology-related parenting strategies across developmental stages. However, the association of these strategies to child screen time and, in turn, problem behaviors, diminished as children increased in age. Implications for intervention are considered

Association of Epigenetic Age and Outcome in Critically Ill Patients

OBJECTIVES: DNA methylation can be used to determine an individual’s biological age, as opposed to chronological age, an indicator of underlying health status. This study aimed to assess epigenetic age in critically ill patients with and without sepsis to determine if higher epigenetic age is associated with admission diagnosis or mortality.DESIGN: Secondary analysis of whole blood DNA methylation data generated from a nested case–control study of critically ill septic and nonseptic patients.SETTING: Four tertiary care hospitals in Canada.INTERVENTIONS: None.PATIENTS: Critically ill patients with and without sepsis.MEASUREMENTS AND MAIN RESULTS: Epigenetic age was derived from DNA methylation data using the Hannum and PhenoAge algorithms and deviation from the patient’s chronological age in years was determined. Of the 66 patients with sepsis, 34 were male (51.5%), the mean age was 65.03 years and 25 patients (37.8%) died before discharge. Of the 68 nonseptic patients, 47 were male (69.1%), the mean age was 64.92 years and 25 (36.7%) died before discharge. Epigenetic age calculated using the PhenoAge algorithm showed a significant age acceleration of 4.97 years in septic patients (p = 0.045), but no significant acceleration in nonseptic patients. Epigenetic age calculated using the Hannum algorithm showed no significant acceleration in the septic or nonseptic patients. Similarly, in the combined septic and nonseptic cohorts, nonsurvivors showed an epigenetic age acceleration of 7.62 years (p = 0.004) using the PhenoAge algorithm while survivors showed no significant age acceleration. Survivor status was not associated with age acceleration using the Hannum algorithm.CONCLUSIONS: In critically ill patients, epigenetic age acceleration, as calculated by the PhenoAge algorithm, was associated with sepsis diagnosis and mortality

Cyclic Alkyl Amino Carbene (CAAC) Ruthenium Complexes as Remarkably Active Catalysts for Ethenolysis

An expanded family of ruthenium-based metathesis catalysts bearing cyclic alkyl amino carbene (CAAC) ligands was prepared. These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. In many cases, catalyst turnover numbers (TONs) of more than 100 000 were achieved, at a catalyst loading of only 3 ppm. Remarkably, the most active catalyst system was able to achieve a TON of 340 000, at a catalyst loading of only 1 ppm. This is the first time a series of metathesis catalysts has exhibited such high performance in cross-metathesis reactions employing ethylene gas, with activities sufficient to render ethenolysis applicable to the industrial-scale production of linear α-olefins (LAOs) and other terminal-olefin products

CenH3/CID Incorporation Is Not Dependent on the Chromatin Assembly Factor CHD1 in Drosophila

CHD1 is a SNF2-related ATPase that is required for the genome-wide incorporation of variant histone H3.3 in the paternal pronucleus as well as in transcriptionally active nuclei in Drosophila embryos. The S. pombe and vertebrate orthologs of CHD1 have been implicated in the assembly of the centromeric histone H3 variant CenH3CENP-A, which occurs in a DNA replication-independent manner. Here, we examined whether CHD1 participates in the assembly of CenH3CID in Drosophila. In contrast to the findings in fission yeast and vertebrate cells, our evidence clearly argues against such a role for CHD1 in Drosophila. CHD1 does not localize to centromeres in either S2 cells or developing fly embryos. Down-regulation of CHD1 in S2 cells by RNAi reveals unchanged levels of CenH3CID at the centromeres. Most notably, ablation of functional CHD1 in Chd1 mutant fly embryos does not interfere with centromere and kinetochore assembly, as the levels and localization of CenH3CID, CENP-C and BubR1 in the mutant embryos remain similar to those seen in wild-type embryos. These results indicate that Drosophila CHD1 has no direct function in the incorporation of the centromeric H3 variant CenH3CID into chromatin. Therefore, centromeric chromatin assembly may involve different mechanisms in different organisms

Simulated Biological Fluid Exposure Changes Nanoceria’s Surface Properties but not its Biological Response

Nanoscale cerium dioxide (nanoceria) has industrial applications, capitalizing on its catalytic, abrasive, and energy storage properties. It auto-catalytically cycles between Ce3+ and Ce4+, giving it pro-and anti-oxidative properties. The latter mediates beneficial effects in models of diseases that have oxidative stress/inflammation components. Engineered nanoparticles become coated after body fluid exposure, creating a corona, which can greatly influence their fate and effects. Very little has been reported about nanoceria surface changes and biological effects after pulmonary or gastrointestinal fluid exposure. The study objective was to address the hypothesis that simulated biological fluid (SBF) exposure changes nanoceria’s surface properties and biological activity. This was investigated by measuring the physicochemical properties of nanoceria with a citric acid coating (size; morphology; crystal structure; surface elemental composition, charge, and functional groups; and weight) before and after exposure to simulated lung, gastric, and intestinal fluids. SBF-exposed nanoceria biological effect was assessed as A549 or Caco-2 cell resazurin metabolism and mitochondrial oxygen consumption rate. SBF exposure resulted in loss or overcoating of nanoceria’s surface citrate, greater nanoceria agglomeration, deposition of some SBF components on nanoceria’s surface, and small changes in its zeta potential. The engineered nanoceria and SBF-exposed nanoceria produced no statistically significant changes in cell viability or cellular oxygen consumption rates