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Copper & friends: Luminescence & triazole based switching
No full textThis thesis describes attempts towards producing a new motif for Cu(I/II) switching that incorporates CuAAC synthesised 1,2,3-triazoles. A variety of techniques is used to explore the properties of new and model ligands, their potential for Cu(I/II) switching and photoswitching. The thesis consists of five chapters, where the work presented in Chapter 2 and Chapters 3/4 was carried out concurrently.
Chapter 1 introduces switching by first discussing several important biological switches. Switching in terms of this thesis is defined and synthetic switches are broadly categorised by the method with which switching is achieved, i.e. chemical, electrochemical or photophysical/photochemical. The photophysics of transition metal complexes is briefly described before an overview of Cu(I/II) switching is provided. Emphasis is placed on the pioneering work of Sauvage and co-workers, and on the HETPHEN strategy reported by Schmittel and co-workers. The previous work from these groups provided the inspiration for the research described in chapters 2-4, where the goal was to move away from polypyridyl systems to the synthetically more facile “click” triazoles while also exploring the potential for a new Cu(I/II) photoswitch.
Chapter 2 outlines previous work by Crowley and co-workers on Cu(I/II) switchable 1,1'-disubstituted ferrocene complexes. CuAAC “click” chemistry is then described, its mechanism presented and its potential to be a promising alternative to the traditionally used polypyridyl systems in Cu(I/II) switching is discussed. A description of the switching systems targeted in this thesis is provided, highlighting the different components of the switch that should provide selectivity for Cu(I) or Cu(II) ions. Following this the synthesis and coordination properties of several model systems, that reflect the different components of the switches, are explored as a means of determining the efficacy of the desired switching systems. Upon confirming the model systems to behave in the expected manner, the synthesis of the switch ligands through “click” chemistry and Pd cross couplings is presented. The coordination properties of the switch ligands with Cu(I) and Cu(II) ions is explored. Followed by a series of competition experiments being performed due to the tridentate pockets within the switch ligands being hypodentate, resulting in the binding of Cu(I) ions at this site. Finally, an interesting result in which an oxo-bridged diCu(II) complex was obtained, reminiscent of hemocyanin, is discussed as well as its potential for future study.
Chapter 3 explores the electrochemical and photophysical properties of a small family of 2-pyridyl-1,2,3-triazole Cu(I) complexes. The use of 2-pyridyl-1,2,3-triazole (pytri) ligands for the development of photophysically active transition metal complexes is broadly examined, before emphasis is placed on previous studies of 2-pyridyl-1,2,3-triazole Cu(I) complexes. The overarching goal of the work presented in the chapter was to attempt to develop a photoswitchable Cu(I/II) system. To achieve this a study of the properties of Cu(I) pytri complexes was undertaken. Given the parent [Cu(pytri)(diMesbpy)](PF6) complex proved to be non-emissive the effects of adding a known chromophoric substituent (TPA) and a change of ancillary ligand were examined.
Chapter 4 moves away from 1,2,3-triazole ligands to look at a 6,6'-diTPA-2,2'-bipyridine (diTPAbpy) ligand as an alternative ancillary ligand in the HETPHEN strategy. Again, the overall intention was towards producing a photoswitchable Cu(I/II) system. Previous literature on analogous ligands are discussed, though surprisingly this 6,6' disubstituted ligand had not been reported despite studies on both its 4,4' and 5,5' analogues. As such the synthesis of diTPAbpy is described and its coordination chemistry with 4- and 6-coordinate transition metals explored. The compounds electronic properties are also examined.
Chapter 5 gives a summary of the work presented in the thesis, while also providing several avenues for further study. These include adjustments to the switch ligands to improve selectivity, alternative chromophoric substituents for photoswitching and the possible use of ligands within the thesis to produce supramolecular architectures
Where is an emotion?
No full textBackground. In 1884, William James asked, “What is an emotion?” and stated that it emerges from perception of the body. Well over a century later, contemporary psychology is still split over what constitutes emotion. The contemporary articulation of James’ “embodied” view of emotion centres on “interoception”: sensing one’s physiological condition. Greater interoception has been shown to increase emotional awareness, improve emotion regulation, and is associated with lower suicidality. “Visceroception” (sensing the viscera, including the heart, gut and lungs), is a type of interoception and of core importance in emotion research. However, interoception is in general dominated by “exteroception” (sensing the external world), hence attention to the physiological condition of the body is largely inhibited. Mitigating exteroceptive dominance using visceroception may disinhibit attention to hitherto unsuspected features of emotion. In particular, no previous emotion study has investigated whether comparisons between different forms of visceroception may reveal localised phenomena in a visceral system (i.e., localised emotion). This poses a new question: “Where is an emotion?”
Aims. The overarching aim of this thesis is to advance understanding of the localisation of emotion via interoceptive training and how this may relate to emotion regulation, with a view to laying the groundwork for the development of interventions that could pertain to suicidality. The research questions are as follows:
(1) Is emotional/affective feeling localised?
(2) Can targeted interoception result in indications of localised emotion?
(3) Is the unlocalisability of emotional feeling due to inhibition?
(4) What implications does access to localised emotion have for emotion regulation in its relationship with suicide prevention?
Methods/procedures. A varied methodological approach was taken, involving laboratory-based reaction time tasks, body-mapping, traditional self-report tools, physiological measurements, systematic assessments of the literature, and conceptual analyses. Three groups were compared over two time points with an intervening visceroceptive training period: a gastroception group (visceroception of the gut); a cardioception group (visceroception of the heart); and a control group. Six studies were undertaken:
(1) A philosophical/theoretical analysis of the intelligibility of localised emotion;
(2) An integrative review of emotional sensations and physiological measurement;
(3) A scoping review of alexithymia and suicidality;
(4) An emotional spatial cueing task;
(5) An emotional stop/signal task;
(6) An analysis of self-report measurements of interoception and emotion regulation.
Results. The combination of laboratory and self-report tool findings suggested a set of localised phenomena in the gastroception group. These included increased interoception, slowed reaction times on the spatial cueing and stop/signal tasks, coalescence of body map responses in the lower abdominal area, lower emotional reactivity, and signs of increased emotion regulation. This interpretation is presented in the thesis alongside rival interpretations of the findings.
Conclusions/implications. In connection with the evidence bases on suicidality and gut physiology, the findings may suggest a promising role for gastroception in improving emotion regulation, and lowering suicide risk. In reframing James’ original question as “Where is an emotion?”, the final suggestion of the thesis is that the gastrointestinal tract may, in a literal sense, be where emotion is
The Nature of Ceramic Production at Unai Bapot, House of Taga and Ritidian at 3,500 cal BP
No full textThis thesis presents the results of a chemical analysis on pottery to investigate the nature of
mobility and interaction from three Mariana Islands sites from 3,500 cal BP to 300 cal BP.
These sites were: House of Taga on Tinian, Unai Bapot on Saipan, and Ritidian on Guam.
Pottery was an important part of the pre-contract period of Chamoru culture and one of the
most common types of material culture found in these sites. The study of their pottery helps
unravel the past on these peoples to understand the nature of their pottery production and in
turn the state of mobility and interaction as a society. This archaeological signature is a
technology which can be traced back to Austronesian ancestors and cultural routes
somewhere in ISEA and connects them culturally with other island groups in Micronesia and
the wider Pacific.
This study focused on the pottery production techniques of the potters for each of the three
sites to discover how they sourced the materials to make their pots. To aid in this,
methodologies developed through the study of Lapita pottery were employed to answer these
questions. Summerhayes (2000a) models were applied to the chemical analysis results
generated from the scanning electron microscope to understand the pottery production
strategies of the potters, but also predict their level of mobility as a society. These factors
were observed through their sourcing of clay and sand, and how these changed as a result of
greater cultural trends such as the initial settlement of the islands, and the Latte Period.
This study was not the first of its kind in this region but was the first to employ the models by
Summerhayes (2000a). Through this analysis, it is argued that the pottery production
strategies and the state of mobility of each of these three sites in the Mariana Islands mirrored
common trends observed in other parts of the Pacific. That with first colonisation of islands,
they practiced an exploratory phase of material experimentation to make their pots drawing
from many different areas for their clay and sands. This reflects a highly mobile society early
on with shared cultural trends across sites. Overtime as the colonisation phase ends and
populations grow this exploratory phase ends and the variation of clay and sand samples
drops in numbers as potters use favoured local materials for their pots. This reflects a more
sedentary society, which still had interaction ties between different islands through shared
cultural traditions but becoming regionalised over time. All three sites show these trends with
evidence of variation between them
Compounding the Abuse: Family Violence, Damages and the Tenancy Tribunal
No full textIn cases where family violence has caused damage to a rented home, a tenant-victim is often found to be liable for that damage. This article considers the interpretation of the Residential Tenancies Act 1986 (RTA) that leads to that result and proposes an alternative interpretation for the family violence context that would achieve fairer outcomes without the need for legislative change. The drafting of the RTA allows space for an interpretation that both takes into account the context of family violence and the policy attempts to prevent family violence. Such a reading acknowledges that not everyone has the physical and social power to control who comes into their home and what they do once admitted. Interpreting the RTA to recognise the realities of family violence would ensure that tenancy law and practice supports the strategy of keeping victims of family violence safe.Peer Reviewe
Dietary Fat Intake and Contributing Food Sources of New Zealand Adolescents: Summarising a Decade
No full textBackground: Dietary fat is an essential macronutrient to support rapid growth and development during adolescence, in addition to maintaining numerous metabolic and physiological roles. However, adolescents are vulnerable to the development of poor dietary habits, typified by higher than recommended intakes of total and saturated fat, which may put them at increased risk of developing chronic diseases later in life. Up to date figures are unavailable due to it being a decade since any national nutrition data was collected among this population.
Objective: To investigate dietary fat intake and contributing food sources of fat among male and female adolescents 15-18 years in New Zealand, comparing intakes between the sexes and against current recommendations to highlight any changes over the past decade and identify areas of concern.
Design: The SuNDiAL (Survey of Nutrition Dietary Assessment and Lifestyle) study is a cross- sectional, multi-centre survey of 266 adolescent females and 135 males 15-18 years of age in New Zealand. Female participants in the study were enrolled between February and September 2019 while males were enrolled between February and April 2020. Self-administered questionnaires were used for the collection of demographic information as well as health and vegetarian status. Two non-consecutive 24-hour recalls were used to assess dietary intake and the Multiple Source Method (MSM) was used to adjust for usual intake. Dietary intake data was collated and analysed using the FoodWorks nutrient database. Anthropometric measures (weight and height) were taken during on-site visits to participating schools.
Results: Estimated mean intakes of total fat as a percentage of total energy in this study exceeded recommendations for both sexes (males: 37.5% (36.5-38.4); females: 36.5% (35.8-37.2)). Saturated Fatty Acid (SFA) intakes were also higher than recommended, with approximately 90% of the population not meeting the current Acceptable Macronutrient Distribution Range (AMDR). Although improvement for polyunsaturated fat (PUFA) intakes were seen when compared to the Adult Nutrition Survey 2008/09 (ANS 08/09), intakes remain low (males: 5.6% (5.2-6.0); females: 5.5% (5.3-5.7). The major food groups of saturated fat for males included poultry, milk and cheese while for females they were cheese, bread-based dishes and biscuits. Primary food sources of polyunsaturated fat were poultry, nuts/seeds and grains/pasta for males, and nuts/seeds, bread and potatoes/kumara/taro for females.
Conclusion: While some positive differences were observed in fat intakes among New Zealand adolescents since the last national survey, overall levels are suboptimal and could be improved by reducing saturated fat and increasing polyunsaturated fat intake. Further research is required to evaluate fat intakes within a nationally representative sample and determine if trends seen in this study are characteristic of intakes across the whole population
Nematic spin vortices in spin-1 Bose-Einstein condensates
No full textSpin-1 Bose-Einstein condensates present a wealth of physics, owing to the spin and superfluid order they possess. In this work, we consider spin-1 condensates with antiferromagnetic interactions, which favor the formation of spin-nematic order. Such condensates may exist in an easy-plane polar phase, and can support various topological defects with associated mass and spin currents. One defect of particular importance is the half-quantum vortex, which possesses both mass and spin circulation. The half-quantum vortex is equivalently realized in binary and easy-plane polar spin-1 condensates, and has been well-characterized theoretically, and observed in experiments. Another defect of interest is the nematic spin vortex, which possesses spin circulation, yet no mass circulation. The nematic spin vortex is thought to be unstable against decay into a pair of half quantum vortices. However, prior to this work, there was no general theory of nematic spin vortex stability.
In this thesis, we develop formalism describing the structure and excitation spectra of axis-symmetric vortices in easy-plane polar spin-1 condensates. We apply this formalism to systematically investigate the structure and linear stability of nematic spin vortices in a uniform system, finding a parameter regime where they may exist as stable defects. We verify our stability predictions with dynamical simulations.
Accurate numerical treatment of the stationary states and excitations of the nematic spin vortex in a uniform system has proved challenging due to the interplay of unstable and Nambu-Goldstone modes. Indeed, we found standard approaches to be ineffective. In this research we have developed new numerical schemes to resolve this issue, ultimately arriving at a robust approach able to provide sufficiently accurate results to illustrate the physics of the system.
Investigation of our results should be possible in current experiments with sodium spin-1 condensates. Here the nematic spin vortices we describe could have implications for the non-equilibrium dynamics following phase transitions between magnetic phases. Furthermore, the numerical and analytic methods we have developed here will have immediate applications to other types of vortices in spin-1 condensates
Consumer Acceptance of Novel Technologies Designed to Control Foodborne Bacteria in China and New Zealand
No full textFoodborne bacteria, such as Listeria monocytogenes, are a heavy burden on human health and the world economy. To better protect consumers from foodborne bacteria while improving food quality, several novel technologies have been developed. The purpose of this study was to investigate Chinese and New Zealand consumers’ acceptance of novel technologies designed to control foodborne bacteria, as well as the effect of providing information on improving their acceptance, and the factors that might be able to influence their acceptance. An online survey was carried out, with 604 and 614 valid responses being collected in China and New Zealand, respectively.
Respondents were asked to rate their acceptance of thermal pasteurisation (TP), high-pressure processing (HPP), irradiation (IR), bacteriophages (BP), antimicrobial packaging (AP), pulsed electric fields (PEF), and rinsing meat carcasses with antimicrobial solutions (RMCA) on three occasions and additional information was provided to respondents after their first and second ratings. After the first rating the material they were provided comprised of information about L. monocytogenes and a brief description of the technology, and after the second rating they were given information on the benefits of the technology. HPP was rated the most acceptable novel food technology in this study, which had the same acceptance as the traditional technology-TP- by the third rating. The acceptance of other novel food technologies was lower than that of TP to differing extents, with rinsing with antimicrobial solutions being rated as the least acceptable technology. In general, Chinese respondents showed a higher acceptance of the technologies.
Information provided in this study influenced consumer acceptance of food technologies. Reading the benefits of a technology had a larger positive effect than reading information about L. monocytogenes and a brief description of the technology. In both countries, scientific reports and relevant national government agents were the most trusted information sources.
The influence of a respondent’s knowledge and behaviours and their acceptance of technologies designed to control foodborne bacteria was investigated, including attitudes toward food technologies, awareness of foodborne bacteria, knowledge about L. monocytogenes, general food safety knowledge, food safety behaviour, food poisoning experience, and demographics. Consumer attitude toward food technologies and consumer awareness of foodborne bacteria were found to be major determinants for consumer acceptance of technologies designed to control foodborne bacteria.
The findings from this research will expand the existing body of knowledge by determining the influence of a wider range of factors on consumer acceptance of food technologies and it will provide useful insights to help the food industry successfully develop, implement, and promote new food processing technologies to ensure food safety
Job satisfaction and career prospects of Oral Health Therapists in Aotearoa/New Zealand: A research update and call for further research in light of the COVID-19 pandemic
No full textPeer Reviewe
A comparison of site occupancy and morphology between Litoria raniformis in Central Otago, New Zealand and Victoria, Australia
No full textMany amphibian species across the globe are at high risk of extinction. Alien species, overexploitation, land-use change, climate change, chemicals, and infectious diseases are all having devastating effects on amphibians. Land-use changes, in particular, are responsible for the declines of many frog species in Australia. However, the Australian frog Litoria raniformis was introduced to New Zealand over 150 years ago and has subsequently colonised the country. This success in a foreign country contrasts the Endangered status of L. raniformis in Australia, but it presents unique opportunities for research and management in New Zealand, which can aid in the conservation of the species in Australia. The overarching goal of this research was to investigate whether L. raniformis in Central Otago, New Zealand have experienced any changes in habitat occupancy or morphology since their move from Australia. I used two groups of L. raniformis in this comparison including populations in Victoria, Australia and populations in Central Otago, New Zealand.
The first aim of this research was to investigate which habitat features determine occupancy of L. raniformis and how habitat differs in Central Otago compared to Victoria. Answering this question required examining occupancy patterns of L. raniformis, and the availability of habitat features. This aim was achieved by conducting habitat assessments on sites in Central Otago and comparing them to habitat assessments already done in Victoria using the same methods. New Zealand and Australia are very different countries regarding both biotic and abiotic features, thus we would expect to see differences in the indigenous and introduced range of L. raniformis. However, amphibians are particularly susceptible to habitat alterations and the presence of habitat features similar to those in the native range has been found to support introduced species. Although, some species have been found to thrive when introduced to sites containing novel habitat features. Therefore, I predicted that similar habitat features across Central Otago and Victoria would predict occupancy of sites; but I also predicted that some difference in sites might be contributing to the abundant population of L. raniformis in New Zealand. There was a trend that L. raniformis preferentially occupied sites that had a higher percentage cover of submerged vegetation over those with low to no cover, in both Central Otago and Victoria. Additionally, Central Otago had significantly more submerged vegetation than Victoria. This finding may contribute to the relative success of L. raniformis in New Zealand compared to Australia. Submerged vegetation is an important habitat feature for L. raniformis reproduction; a higher percentage of submerged vegetation in ponds may enhance breeding success.
The second aim of this study was to investigate whether any shifts in body size had occurred in Central Otago L. raniformis compared to those in Victoria. Answering this question required populations of Central Otago L. raniformis to be weighed and measured, and then compared to the same data already collected in Australia. Litoria raniformis has been in New Zealand for over 150 years and may have experienced changes in morphology in order to adapt to New Zealand’s conditions. Furthermore, Central Otago reaches lower minimum temperatures than Victoria and is on average cooler. According to Bergmann’s Rule, this would suggest that L. raniformis may be larger in Central Otago than in Victoria as a larger body size is more efficient at maintaining heat due to the increased body size: surface ratio. Moreover, insular shifts are known to affect morphology through changes in biotic interactions, of which there would be many in the move from Australia to New Zealand. Therefore, I predicted that L. raniformis in Central Otago would be on average larger than conspecifics in Victoria. This prediction was incorrect as female L. raniformis in New Zealand were smaller, while males were very similarly sized. Competition, food availability, predation, or differing growth periods may have contributed to this effect. However, this requires further research.
The present study demonstrated that L. raniformis in New Zealand exhibit slight differences in site occupancy and morphology. This study has also provided a start to utilising the populations of L. raniformis in New Zealand for research and management techniques that can be applied in Australia