Search

Objective To explore barriers to planned dental visiting, investigating how barriers interlink, how they accumulate and change, and how individuals envisage overcoming their combination of barriers through personal strategies. Methods An ethnographic study was conducted of adult urgent dental care attenders who did not have a dentist, including 155 hours of nonparticipant observations, 97 interviews and 19 follow-up interviews in six urgent dental care settings. Data were analysed using constant comparison, first identifying barriers and personal strategies to overcome them, and subsequently analysing interlinks between barriers and personal strategies. Results Accounts of barriers to planned dental visiting encompassed multiple barriers, which related to socioeconomic circumstances as well as experiences of oral health care. Barriers were multi-layered and more difficult to overcome when occurring together. Personal strategies to overcome diverse barriers often hinged on increasing importance of oral health to individuals, yet this was not always sufficient. The combination of barriers participants experience was dynamic, changing due to personal, family, or employment circumstances, and with increasing severity of barriers over time. Over time, this could lead to higher cost, and additional barriers, particularly embarrassment. Conclusion Barriers to planned dental visiting are complex, multi-layered and change over time, constituting a 'web of causation'. This adds a novel perspective to the literature on barriers to dental visiting, and requires that researchers, dental practitioners and policy makers remain open to barriers' interlinked effects, changes in primacy among individual patients' barriers, and their accumulation over time to better support uptake of planned dental visiting.

Carbonate budgets are increasingly being used as a key metric to establish reef condition. To better under-stand spatial variations in framework and sediment net carbonate budgets, we quantied biogenic carbonateproduction, erosion, and dissolution within and between ve distinct geomorphological habitats of Heron Reefon the southern Great Barrier Reef. The protected reef slope had the greatest estimated net framework carbonatebudget (22.6 kgCaCO3m−2yr−1 2.4 SE), driven by abundant, fast-growing acroporid corals coupled with lowlevels of macro- and micro-bioerosion. The estimate of the exposed reef slope was signicantly lower due tolocalized damage from a single tropical cyclone that occurred 7 years prior to this study (9.7kgCaCO3m−2yr−1 2.8 SE). Within the extensive lagoon, net framework carbonate budgets ranged from0.24 kgCaCO3m−2yr−1( 0.1 SE) to 3.0 kgCaCO3m−2yr−1( 0.7 SE). The greatest net sediment carbonatebudget was estimated within the reef crest (6.0 kgCaCO3m−2yr−1 1.1 SE) and the lowest in the shallowlagoon (1.2 kgCaCO3m−2yr−1 0.2 SE). Chemical dissolution of the sediments exhibited spatial variability,with reef crest and reef  at sediments in a state of net production. Considering the area of each habitat, the netreef framework and sediment budgets across Heron Reef were 4.06 kgCaCO3m−2yr−1and2.82 kgCaCO3m−2yr−1, respectively. The results of this study improve our understanding of spatial variabilityin carbonate production and bioerosion and provide a comprehensive reef-scale carbonate budget for a rela-tively undisturbed coral reef ecosystem.

Despite recent efforts to curtail greenhouse gas emissions, current global emission trajectories are still following the business-as-usual representative concentration pathway (RCP) 8.5 emission pathway. The resulting ocean warming and acidification have transformative impacts on coral reef ecosystems, detrimentally affecting coral physiology and health, and these impacts are predicted to worsen in the near future. In this study, we kept fragments of the symbiotic corals Acropora intermedia (thermally sensitive) and Porites lobata (thermally tolerant) for 7 weeks under an orthogonal design of predicted end-of-century RCP8.5 conditions for temperature and pCO(2) (3.5 degrees C and 570 ppm above present-day, respectively) to unravel how temperature and acidification, individually or interactively, influence metabolic and physiological performance. Our results pinpoint thermal stress as the dominant driver of deteriorating health in both species because of its propensity to destabilize coral-dinoflagellate symbiosis (bleaching). Acidification had no influence on metabolism but had a significant negative effect on skeleton growth, particularly when photosynthesis was absent such as in bleached corals or under dark conditions. Total loss of photosynthesis after bleaching caused an exhaustion of protein and lipid stores and collapse of calcification that ultimately led to A. intermedia mortality. Despite complete loss of symbionts from its tissue, P. lobata maintained small amounts of photosynthesis and experienced a weaker decline in lipid and protein reserves that presumably contributed to higher survival of this species. Our results indicate that ocean warming and acidification under business-as-usual CO2 emission scenarios will likely extirpate thermally sensitive coral species before the end of the century, while slowing the recovery of more thermally tolerant species from increasingly severe mass coral bleaching and mortality. This could ultimately lead to the gradual disappearance of tropical coral reefs globally, and a shift on surviving reefs to only the most resilient coral species.

2D monolayers represent some of the most deformable inorganic materials, with bending stiffnesses approaching those of lipid bilayers. Achieving 2D heterostructures with similar properties would enable a new class of deformable devices orders of magnitude softer than conventional thin-film electronics. Here, by systematically introducing low-friction twisted or heterointerfaces, interfacial engineering is leveraged to tailor the bending stiffness of 2D heterostructures over several hundred percent. A bending model is developed and experimentally validated to predict and design the deformability of 2D heterostructures and how it evolves with the composition of the stack, the atomic arrangements at the interfaces, and the geometry of the structure. Notably, when each atomic layer is separated by heterointerfaces, the total bending stiffness reaches a theoretical minimum, equal to the sum of the constituent layers regardless of scale of deformation-lending the extreme deformability of 2D monolayers to device-compatible multilayers.

The problem of soot emissions from diesel engines is introduced and the possible solution of combining doped perovskites and microwave (mw) irradiation to "clean up" diesel soot filters is outlined. Eighteen doped perovskite catalysts are synthesized and tested for propane and CO oxidation, which are taken as model components for soot. The activity, selectivity, and SO 2 tolerance are compared under conventional heating and mw irradiation. By combining mw irradiation and doped perovskites, one can create "hot spots" on the catalyst, resulting in efficient and selective heating of the active site, as well as less poisoning. Sr-doped and Ce-doped manganese perovskites show the highest activity. These catalysts are also the most selective, and have a high mw susceptibility. Optimal SO 2 tolerance is displayed by Cr perovskites, from which the La 0.8 Ca 0.2 CrO 3 combination uniquely converts propane before CO, and therefore can be used to remove > C 2 hydrocarbons from a mix with CO. Possible mechanistic scenarios are presented and discussed.

A strategy is reported for the controlled assembly of organic-inorganic heterostructures consisting of individual single-walled carbon nanotubes (SWCNTs) selectively coupled to single semiconductor quantum dots (QDs). The assembly in aqueous solution was controlled towards the formation of monofunctionalized SWCNT-QD structures. Photoluminescence studies in solution, and on surfaces at the single nanohybrid level, showed evidence of electronic coupling between the two nanostructures. The ability to covalently couple heterostructures with single particle control is crucial for the design of novel QD-based optoelectronic and light-energy conversion devices.

Direct photo-patterning of polyimide (PI) films was done in two ways, both based upon the modification of the PI-precursor, the polyamic acid (PAA), by derivatives of methacrylic amide. In the first method, a photoreactive PAA is prepared by partially (25 mole percent) neutralizing PAA with N-(N′N′-dimethylarnino)propylmethacrylic amide and completing the neutralization with methacrylic amide (75 mole percent). In the second method the PAA is esterified, e.g. with N-hydroxyethyl-N-methylmethacrylic amide, through its isourea derivative. The modified PAAs are processed like conventional negative photoresists. In the first method, the photopolymer formed by selective UV exposure is bound to the PAA by intermaeromolecular complexation, causing insolubility in the developer. The second method, which was investigated only qualitatively, provides crosslinked patterns. In both cases a pure PI film is left upon imidization at 350°C. The first method proved to be well-suited to making the potential well structure in an electrophoretic image display. These wells must have strictly vertical walls (12 μm high) with metallized top faces. It was found that mask contact at “molecular distance” is not needed for the exposure of the photosensitive PAA: vertical walls could be made by simply adapting the developer after contact exposure. This is explained, tentatively, by the typical characteristics of the polymer-polymer complex upon development. The potential well structure could now be made in a straightforward process.