299 research outputs found
Synthesis and multinuclear magnetic resonance studies of some nitrogen-containing ceramic phases
This Thesis describes the synthesis of a range of sialon ceramic phases, and their characterisation using multinuclear magnetic resonance and powder X-ray diffraction.Sihcon-29 and aluminium-27 MAS NMR spectroscopies have been used in the past on a range of inorganic systems, with considerable success. In this study, they were applied to phases in M-Si-Al-O-N systems, with M=La, Y, Li, Mg and Ca, leading to an improved understanding of the factors affecting chemical shifts and other NMR parameters. It was found that some structural information on, for example, 0/N ordering was not available from (^29)Si and (^27)Al NMR, but could be obtained from studies of other nuclei. Nitrogen-15 and oxygen-17 were selected for further study. The low natural abundances of these nuclei meant that isotopically enriched materials had to be prepared. The synthesis of a-Si(^15)(_3)N(_4), Mg(^17)O and Si(^17)O(_2), and of enriched sialon materials is described, and also (^15)N and (^17)0 MAS NMR studies of many sialon phases. In particular, the (^15)N and (^29)Si spectra of lanthanum new phase, a phase of previously unknown structure, were combined with a Patterson map from powder XRD data to allow the crystal structure of this phase to be determined. Finally, the feasibility of using other nuclei to study ceramic structures has been investigated, and (^9)Be, (^7)Li and (^139)La NMR spectra of several phases are reported
An evidence-based health workforce model for primary and community care
<p>Abstract</p> <p>Background</p> <p>The delivery of best practice care can markedly improve clinical outcomes in patients with chronic disease. While the provision of a skilled, multidisciplinary team is pivotal to the delivery of best practice care, the occupational or skill mix required to deliver this care is unclear; it is also uncertain whether such a team would have the capacity to adequately address the complex needs of the clinic population. This is the role of needs-based health workforce planning. The objective of this article is to describe the development of an evidence-informed, needs-based health workforce model to support the delivery of best-practice interdisciplinary chronic disease management in the primary and community care setting using diabetes as a case exemplar.</p> <p>Discussion</p> <p>Development of the workforce model was informed by a strategic review of the literature, critical appraisal of clinical practice guidelines, and a consensus elicitation technique using expert multidisciplinary clinical panels. Twenty-four distinct patient attributes that require unique clinical competencies for the management of diabetes in the primary care setting were identified. Patient attributes were grouped into four major themes and developed into a conceptual model: the Workforce Evidence-Based (WEB) planning model. The four levels of the WEB model are (1) promotion, prevention, and screening of the general or high-risk population; (2) type or stage of disease; (3) complications; and (4) threats to self-care capacity. Given the number of potential combinations of attributes, the model can account for literally millions of individual patient types, each with a distinct clinical team need, which can be used to estimate the total health workforce requirement.</p> <p>Summary</p> <p>The WEB model was developed in a way that is not only reflective of the diversity in the community and clinic populations but also parsimonious and clear to present and operationalize. A key feature of the model is the classification of subpopulations, which gives attention to the particular care needs of disadvantaged groups by incorporating threats to self-care capacity. The model can be used for clinical, health services, and health workforce planning.</p
Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit
Engineered functional surfaces often feature varying slopes on macro- and micro-scales. When surfaces are mirror-like, the highest surface slope that can be measured by a far-field 3D imaging optical surface measuring instrument isthe arcsine of the numerical aperture (NA) of the objective lens, i.e. the acceptance angle of the lens. However, progress in instrument design has allowed for measurement of non-specular surfaces with slopes steeper than this âtraditionalâ NA limit. Nonetheless, there is currently a lack of understanding about the instrument response to surfaces with steep slopes beyond this limit. It is unclear over what surface spatial frequencies we can expect to accurately report fine surface-feature details. Here we present results demonstrating the capability of a commercial coherence scanning interferometer for measuring surface topography of a roughened flat and a blazed grating with tilt angles greater than the NA slope limit. We show that the surface form, i.e. the tilted plane, can be measured correctly. But, while surface texture information that can appear useful is also obtained, tilting significantly influences the measurement accuracy of micro-scale texture, and for asymmetric gratings, can depend on the tilting direction. A simplified surface scattering model suggests that the loss of scattered power captured by the instrument and a low signal-to-noise ratio causes the reduction of measurement accuracy. However, a rigorous three-dimensional instrument model is needed for a full understanding; we will develop this in our future work
The Diabetes Care Project: an Australian multicentre, cluster randomised controlled trial [study protocol]
Background:
Diabetes mellitus is an increasingly prevalent metabolic disorder that is associated with substantial disease burden. Australia has an opportunity to improve ways of caring for the growing number of people with diabetes, but this may require changes to the way care is funded, organised and delivered. To inform how best to care for people with diabetes, and to identify the extent of change that is required to achieve this, the Diabetes Care Project (DCP) will evaluate the impact of two different, evidence-based models of care (compared to usual care) on clinical quality, patient and provider experience, and cost.
Methods/Design:
The DCP uses a pragmatic, cluster randomised controlled trial design. Accredited general practices that are situated within any of the seven Australian Medicare Locals/Divisions of General Practice that have agreed to take part in the study were invited to participate. Consenting practices will be randomly assigned to one of three treatment groups for approximately 18 to 22 months: (a) control group (usual care); (b) Intervention 1 (which tests improvements that could be made within the current funding model, facilitated through the use of an online chronic disease management network); or (c) Intervention 2 (which includes the same components as Intervention 1, as well as altered funding to support voluntary patient registration with their practice, incentive payments and a care facilitator). Adult patients who attend the enrolled practices and have established (âĽ12 month's duration) type 1 diabetes mellitus or newly diagnosed or established type 2 diabetes mellitus are invited to participate. Multiple outcomes will be studied, including changes in glycosylated haemoglobin (primary outcome), changes in other biochemical and clinical metrics, incidence of diabetes-related complications, quality of life, clinical depression, success of tailored care, patient and practitioner satisfaction, and budget sustainability.
Discussion:
This project responds to a need for robust evidence of the clinical and economic effectiveness of coordinated care for the management of diabetes in the Australian primary care setting. The outcomes of the study will have implications not only for diabetes management, but also for the management of other chronic diseases, both in Australia and overseas
Quantifying the potential exposure hazard due to energetic releases of CO2 from a failed sequestration well
AbstractWells are designed to bring fluids from depth to the earthâs surface quickly. As such they are the most likely pathway for CO2 to return to the surface in large quantities and present a hazard without adequate management. We surveyed oil industry experience of CO2 well failures, and separately, calculated the maximal CO2 flow rate from a 5000 ft depth supercritical CO2 reservoir. The calculated maximum of 20,000 tonne/day was set by the sound speed and the seven-inch well casing diameter, and was greater than any observed event. We used this flux to simulate atmospheric releases and the associated hazard utilizing the National Atmospheric Release Advisory Center (NARAC) tools and real meteorology at a representative location in the High Plains of the United States. Three cases representing a maximum hazard day (quiet winds <1 m sâ1 near the wellhead) and medium and minimal hazard days (average winds 3 m sâ1 and 7 m sâ1) were assessed. As expected for such large releases, there is a near-well hazard when there is little or no wind. In all three cases the hazardous Temporary Emergency Exposure Levels (TEEL) 2 or 3 only occurred within the first few hundreds of meters. Because the preliminary 3-D model runs may not have been run at high enough resolution to accurately simulate very small distances, we also used a simple Gaussian plume model to provide an upper bound on the distance at which hazardous conditions might exist. This extremely conservative model, which ignores inhomogeneity in the mean wind and turbulence fields, also predicts possible hazardous concentrations up to several hundred meters downwind from a maximal release
The association between community mental health nursing and hospital admissions for people with serious mental illness: a systematic review.
BACKGROUND:Relapse prevention is an important objective in the management of serious mental illness (SMI). While community mental health nurses (CMHN) might be well-placed to support people with SMI in averting relapse, no systematic reviews have examined this association. AIM:To review the evidence from studies reporting an association between CMHN exposure and hospitalisation of persons living with SMI (a proxy for relapse). METHODS:Searches were undertaken in ten bibliographic databases and two clinical trial registries. We included studies of patients with SMI, where CMHN was the exposure, and the outcome was relapse (i.e. readmission to a psychiatric inpatient facility). Quality assessment of included studies was completed using two risk-of-bias measures. RESULTS:Two studies met the inclusion criteria. Studies were rated as being of low-moderate methodological quality. There was insufficient evidence to conclude that community mental health nursing reduced the risk of admission to psychiatric inpatient facilities. CONCLUSIONS:The review found no evidence that CMHN was associated with higher or lower odds of admission to psychiatric inpatient facilities among patients with SMI. The findings of the review point to a need for further research to investigate the impact of CMHN exposure and relapse in people with SMI. SYSTEMATIC REVIEW REGISTRATION:PROSPERO CRD42017058694
Asymmetric synthesis of heterocyclic chloroamines and aziridines by enantioselective protonation of catalytically generated enamines
L.A.M. and J.W.B.F. thank EPSRC for postdoctoral funding (EP/S027165/1; EP/R025754/1). J.W.B.F. thanks the Leverhulme Trust for postdoctoral funding (RPG-2018-362). M.W.A. thanks the University of St Andrews for a PhD studentship.We report a method for the synthesis of chiral vicinal chloroamines via asymmetric protonation of catalytically generatedprochiral chloroenamines using chiral Brønsted acids. The processis highly enantioselective, with the origin of asymmetry and catalystsubstituent effects elucidated by DFT calculations. We show theutility of the method as an approach to the synthesis of a broadrange of heterocycle-substituted aziridines by treatment of thechloroamines with base in a one-pot process, as well as the utility ofthe process to allow access to vicinal diamines.Publisher PDFPeer reviewe
Ample evidence for fish sentience and pain
The majority of commentaries are supportive of our position on the scepticism that muddies the waters surrounding fish pain and sentience. There is substantial empirical evidence for pain in fish. Animalsâ experience of pain cannot be compared to artificial intelligence (AI) because AI can only mimic responses to nociceptive input on the basis of human observations and programming. Accepting that fish are sentient would not be detrimental to the industries reliant on fish. A more proactive discussion between scientists and stakeholders is needed to improve fish welfare for the benefit of all
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