517 research outputs found

    Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit

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    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 ā€œtraditionalā€ 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

    Combined inkjet printing and infrared sintering of silver nanoparticles using a swathe-by-swathe and layer-by-layer approach for 3-dimensional structures

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    Despite the advancement of additive manufacturing (AM)/3-dimensional (3D) printing, single-step fabrication of multifunctional parts using AM is limited. With the view of enabling multifunctional AM (MFAM), in this study, sintering of metal nanoparticles was performed to obtain conductivity for continuous line inkjet printing of electronics. This was achieved using a bespoke three dimensional (3D) inkjet-printing machine, JETxĀ®, capable of printing a range of materials and utilizing different post processing procedures to print multi-layered 3D structures in a single manufacturing step. Multiple layers of silver were printed from an ink containing silver nanoparticles (AgNPs) and infra-red sintered using a swathe-by-swathe (SS) and layer-by-layer sintering (LS) regime. The differences in the heat profile for the SS and LS was observed to influence the coalescence of the AgNPs. Void percentage of both SS and LS samples was higher towards the top layer than the bottom layer due to relatively less IR exposure in the top than the bottom. The results depicted a homogeneous microstructure for LS of AgNPs and showed less deformation compared to the SS. Electrical resistivity of the LS tracks (13.6 Ā± 1Ī¼Ī© cm) was lower than the SS tracks (22.5 Ā± 1 Ī¼Ī© cm). This study recommends the use of LS method to sinter the AgNPs to obtain a conductive track in 25% less time than SS method for MFAM

    The association between community mental health nursing and hospital admissions for people with serious mental illness: a systematic review.

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    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

    Defect evolution in laser powder bed fusion additive manufactured components during thermo-mechanical testing

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    The mechanical performance of additively manufactured (AM) components remains an issue, limiting the implementation of AM technologies. In this work, a new method is presented, to examine the evolution of defects in an Inconel 718 two-bar test specimen, manufactured by laser powder bed fusion AM, during thermo-mechanical testing. The test was interrupted at specific extensions of the specimen, and X-ray computed tomography measurements performed. This methodology has allowed, for the first time, the evolution of the defects in an AM specimen to be studied during a thermo-mechanical test. The number and size of the defects were found to increase with time as a result of the thermo-mechanical test conditions, and the location and evolution of these defects have been tracked. Defect tracking potentially allows for accurate prediction of failure positions, at the earliest possible stage of a thermo-mechanical test. Ultimately, when the ability to locate defects in this manner is coupled with manipulation of build parameters, laser powder bed fusion practitioners will be able to further optimise the manufacturing procedure in order to produce components of a higher structural integrity

    Results from an interlaboratory comparison of areal surface texture parameter extraction from X-ray computed tomography of additively manufactured parts

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    This paper presents the results of the CT-STARR (CT-Surface Texture for Additive Round Robin) interlaboratory comparison. The study compares the results obtained for the extraction of areal surface texture data per ISO 25178-2 from five X-ray computed tomography (XCT) volume measurements from each of four laboratories. To reduce the number of process variables, all participants utilise a Nikon XCT machine, either an XT H 225 industrial CT or an MCT225 metrology CT. Measurement process parameters, such as physical X-ray filtering, acceleration voltage and filament current, are set at similar values for all machines. All data processing and computation to extract, align, crop, filter and generate surface texture parameter information and deviation analysis results from the measurement volumes is performed by one participant. Two Ti6Al4V ELI (extra low interstitial) components are included in each of the XCT acquisitions. The first component is an additively manufactured cube built on an Arcam Q10 electron beam melting machine. Surface texture data is extracted from XCT scans of this part. The second component is a machined artefact designed for XCT scaling and surface determination analysis and verification. The data extracted from XCT measurements of these components is compared with measurements from coordinate measuring machine, focus variation and stylus instruments. The effect of scaling correction and XCT surface determination on extracted surface texture data, as well as measurement repeatability and reproducibility, are discussed

    Quality of relationships as predictors of outcomes in people with dementia: a systematic review protocol

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    INTRODUCTION: Serious adverse outcomes for people with dementia include institutionalisation, hospitalisation, death, development of behavioural and psychiatric symptoms, and reduced quality of life. The quality of the relationship between the person with dementia and their informal/family carer is thought to affect the risk of these outcomes. However, little is known about which aspects of relationship quality are important, or how they affect outcomes for people with dementia. METHODS AND ANALYSIS: This will be a systematic review of the literature. Electronic databases MEDLINE, EMBASE, Web of Science, PsycInfo, the Cochrane Database, ALOIS and OpenGrey will be searched from inception. 2 independent reviewers will screen results for eligibility with standardised criteria. Data will be extracted for relevant studies, and information on the associations between relationship quality and dementia outcomes will be synthesised. Meta-analysis will be performed if possible to calculate pooled effect sizes. Narrative synthesis will be performed if study heterogeneity rules out meta-analysis. ETHICS AND DISSEMINATION: Ethical review is not necessary as this review summarises data from previous studies. Results will be disseminated via peer-reviewed publication. Results will also be disseminated to a patient and public involvement group and an expert panel for their views on the findings and implications for future work. TRIAL REGISTRATION NUMBER: CRD42015020518

    Verification of micro-scale photogrammetry for smooth three-dimensional object measurement

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    By using sub-millimetre laser speckle pattern projection we show that photogrammetry systems are able to measure smooth three-dimensional objects with surface height deviations less than 1 Ī¼m. The projection of laser speckle patterns allows correspondences on the surface of smooth spheres to be found, and as a result, verification artefacts with low surface height deviations were measured. A combination of VDI/VDE and ISO standards were also utilised to provide a complete verification method, and determine the quality parameters for the system under test. Using the proposed method applied to a photogrammetry system, a 5 mm radius sphere was measured with an expanded uncertainty of 8.5 Ī¼m for sizing errors, and 16.6 Ī¼m for form errors with a 95 % confidence interval. Sphere spacing lengths between 6 mm and 10 mm were also measured by the photogrammetry system, and were found to have expanded uncertainties of around 20 Ī¼m with a 95 % confidence interval

    Pulmonary stretch receptor activity during partial liquid ventilation in cats with healthy lungs

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    Aim: To study whether pulmonary stretch receptor (PSR) activity in mechanically ventilated young cats with healthy lungs during partial liquid ventilation (PLV) is different from that during gas ventilation (GV). Methods: In 10 young cats (4.4 +/- 0.4 months, 2.3 +/- 0.3 kg; mean B SD), PSR instantaneous impulse frequency (PSR f(imp)) was recorded from single fibres in the vagal nerve during GV and PLV with perfluorocarbon (30 ml/kg) at increasing positive inspiratory pressures (PIP; 1.2, 1.8, 2.2 and 2.7 kPa), and at a positive end-expiratory pressure of 0.5 kPa. Results: All PSRs studied during GV maintained their phasic character with increased impulse frequency during inspiration during PLV. Peak PSR fimp was lower at PIP 1.2 kPa (p < 0.05) and at PIP 2.7 kPa (p = 0.10) during PLV than during GV, giving a lower number of PSR impulses at these two settings during PLV (p < 0.05). Conclusion: The phasic character of PSR activity is similar during GV and PLV. PSR activity is not higher during PLV than during GV in cats with healthy lungs, indicating no extensive stretching of the lung during PLV. Copyright (C) 2004 S. Karger AG, Basel

    Primary physical education, coaches and continuing professional development

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    This is an Author's Accepted Manuscript of an article published in Sport, Education and Society, 16(4), 485 - 505, 2011, copyright @ Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/13573322.2011.589645.Physical education (PE) in primary schools has traditionally been taught by qualified primary teachers. More recently, some teaching of PE in primary schools has been undertaken by coaches (mostly football coaches). These coaches hold national governing body awards but do not hold teaching qualifications. Thus, coaches may not be adequately prepared to teach PE in curriculum time. The purpose of this study was to evaluate the perceptions of a group of community-based football coaches working in primary schools for the impact of a Continuing Professional Development (CPD) programme on their ability to undertake ā€˜specified workā€™ to cover PE in primary schools. The programme focused on four areas identified as important to enable coaches to cover specified work: short- and medium-term planning, pedagogy, knowledge of the curriculum and reflection. Results showed that for the majority of coaches the CPD programme had made them more aware of the importance of these four areas and had helped to develop their knowledge and ability to put this into practice in covering planning, preparation and assessment time. However, further input is still required to develop coachesā€™ knowledge and understanding in all four areas, but especially their curriculum knowledge, as well as their ability to put these into practice consistently. These findings are discussed in relation to the implications of employing coaches to cover the teaching of PE in primary schools and, if employed, what CPD coaches need to develop the necessary knowledge, skill and understanding for covering specified work in schools

    Targeting the LOX/hypoxia axis reverses many of the features that make pancreatic cancer deadly: inhibition of LOX abrogates metastasis and enhances drug efficacy

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    Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancerā€related mortality. Despite significant advances made in the treatment of other cancers, current chemotherapies offer little survival benefit in this disease. Pancreaticoduodenectomy offers patients the possibility of a cure, but most will die of recurrent or metastatic disease. Hence, preventing metastatic disease in these patients would be of significant benefit. Using principal component analysis (PCA), we identified a LOX/hypoxia signature associated with poor patient survival in resectable patients. We found that LOX expression is upregulated in metastatic tumors from Pdx1ā€Cre KrasG12D/+ Trp53R172H/+ (KPC) mice and that inhibition of LOX in these mice suppressed metastasis. Mechanistically, LOX inhibition suppressed both migration and invasion of KPC cells. LOX inhibition also synergized with gemcitabine to kill tumors and significantly prolonged tumorā€free survival in KPC mice with earlyā€stage tumors. This was associated with stromal alterations, including increased vasculature and decreased fibrillar collagen, and increased infiltration of macrophages and neutrophils into tumors. Therefore, LOX inhibition is able to reverse many of the features that make PDAC inherently refractory to conventional therapies and targeting LOX could improve outcome in surgically resectable disease
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