Fast and Accurate Coarsening Simulation with an Unconditionally Stable Time Step

We present Cahn-Hilliard and Allen-Cahn numerical integration algorithms that are unconditionally stable and so provide significantly faster accuracy-controlled simulation. Our stability analysis is based on Eyre's theorem and unconditional von Neumann stability analysis, both of which we present. Numerical tests confirm the accuracy of the von Neumann approach, which is straightforward and should be widely applicable in phase-field modeling. We show that accuracy can be controlled with an unbounded time step Delta-t that grows with time t as Delta-t ~ t^alpha. We develop a classification scheme for the step exponent alpha and demonstrate that a class of simple linear algorithms gives alpha=1/3. For this class the speed up relative to a fixed time step grows with the linear size of the system as N/log N, and we estimate conservatively that an 8192^2 lattice can be integrated 300 times faster than with the Euler method.Comment: 14 pages, 6 figure

Dynamic Phase Transitions in Cell Spreading

We monitored isotropic spreading of mouse embryonic fibroblasts on fibronectin-coated substrates. Cell adhesion area versus time was measured via total internal reflection fluorescence microscopy. Spreading proceeds in well-defined phases. We found a power-law area growth with distinct exponents a_i in three sequential phases, which we denote basal (a_1=0.4+-0.2), continous (a_2=1.6+-0.9) and contractile (a_3=0.3+-0.2) spreading. High resolution differential interference contrast microscopy was used to characterize local membrane dynamics at the spreading front. Fourier power spectra of membrane velocity reveal the sudden development of periodic membrane retractions at the transition from continous to contractile spreading. We propose that the classification of cell spreading into phases with distinct functional characteristics and protein activity patterns serves as a paradigm for a general program of a phase classification of cellular phenotype. Biological variability is drastically reduced when only the corresponding phases are used for comparison across species/different cell lines.Comment: 4 pages, 5 figure

Self-directed self-management interventions to prevent or address distress in young people with long-term physical conditions: a rapid review.

Background: Comorbid distress in adolescents and young adults with physical long‐ term conditions (LTCs) is common but can be difficult to identify and manage. Self‐ directed self‐management interventions to reduce distress and improve wellbeing may be beneficial. It is unknown, however, which intervention characteristics are successful in supporting young people. This rapid review aimed to identify characteristics of self‐directed self‐management interventions that aimed, in whole or part, to address distress, wellbeing or self‐efficacy in this population. Methods: A systematic search was conducted for relevant controlled studies in six databases. Data on study settings, population, intervention characteristics, outcome measures, process measures and summary effects were extracted. The risk of bias was assessed using the Cochrane Risk of Bias tool v1, and the strength of evidence was rated (informed by Grading of Recommendations, Assessment, Development and Evaluations). Patient and public involvement members supported the review process, including interpretation of results. The rapid review was registered with PROSPERO (ID: CRD42021285867). Results: Fourteen studies were included, all of which were randomised trials. Heterogeneity was identified in the health conditions targeted; type of intervention; outcome measures; duration of intervention and follow‐up. Three had distress, wellbeing or self‐efficacy as their primary outcome. Four modes of delivery were identified across interventions—websites, smartphone applications, text messages and workbooks; and within these, 38 individual components. Six interventions had a significant benefit in mental health, wellbeing or self‐efficacy; however, intervention characteristics were similar for beneficial and non‐beneficial interventions. Conclusions: There is a paucity of interventions directly targeting distress and wellbeing in young people with physical LTCs. In those identified, the heterogeneity of interventions and study design makes it difficult to identify which characteristics result in positive outcomes. We propose the need for high‐quality, evidence‐based self‐management interventions for this population; including (1) more detailed reporting of intervention design, content and delivery; (2) robust process evaluation; (3) a core outcome set for measuring mental health and wellbeing for self‐ management interventions and (4) consistency in follow up periods. Public Contribution: Seven young people with an LTC were involved throughout the rapid review, from the development of the review protocol where they informed the focus and aims, with a central role in the interpretation of findings.peer-reviewe

Healthcare professionals’ priorities for training to identify and manage distress experienced by young people with a stoma due to inflammatory bowel disease: a consensus study using online nominal group technique

Young people with a stoma due to inflammatory bowel disease (IBD) commonly experience distress; however, this is not always well managed in clinical settings. More effective support may/is likely to reduce the possibility of individuals experiencing sustained distress, which may engender depression or anxiety. This study aimed to gain consensus among a multidisciplinary group of healthcare professionals (HCPs) on priorities for training in the identification and management of distress in this population. One of the authors is a young person with a stoma. Design Participants were recruited through Twitter (X) and the researchers’ clinical/research contacts. Two consensus group meetings were conducted using Nominal Group Technique, involving participants generating, discussing and rating on a Likert scale, topics for inclusion in an HCP training package. Setting Online video conferencing. Participants were located across England, with one based in the USA. Participants Nineteen HCPs participated: three general practitioners, three stoma nurses, two IBD nurses, nine clinical psychologists and two gastroenterologists. Results Twenty-five topics were generated by participants; 19 reached consensus of ≥80%, that is, a mean of ≥5.6 on a 7-point Likert scale. These included: recognising and validating different levels of, and variation in, distress; tackling stigma and normalising having a stoma; everyday practicalities of stoma management, including food and sleep; opening and holding conversations about stoma-related distress; considering the impact of different cultural beliefs on adaptation after stoma surgery; training in simple techniques for gauging the patient’s distress during clinical encounters; having conversations about body image; and myth-busting common fears, such as odour. Conclusions This study is the first to identify HCP training priorities for managing stoma-related distress in young people. Consensus was reached for 19 topics, reflecting the varied needs of young people with a stoma. Findings will inform development of a training package for HCPs treating young people with IBD and a stoma.peer-reviewe

Anisotropic Coarsening: Grain Shapes and Nonuniversal Persistence

We solve a coarsening system with small but arbitrary anisotropic surface tension and interface mobility. The resulting size-dependent growth shapes are significantly different from equilibrium microcrystallites, and have a distribution of grain sizes different from isotropic theories. As an application of our results, we show that the persistence decay exponent depends on anisotropy and hence is nonuniversal.Comment: 4 pages (revtex), 2 eps figure

A systematic review of machine learning models for predicting outcomes of stroke with structured data

Background and purposeMachine learning (ML) has attracted much attention with the hope that it could make use of large, routinely collected datasets and deliver accurate personalised prognosis. The aim of this systematic review is to identify and critically appraise the reporting and developing of ML models for predicting outcomes after stroke.MethodsWe searched PubMed and Web of Science from 1990 to March 2019, using previously published search filters for stroke, ML, and prediction models. We focused on structured clinical data, excluding image and text analysis. This review was registered with PROSPERO (CRD42019127154).ResultsEighteen studies were eligible for inclusion. Most studies reported less than half of the terms in the reporting quality checklist. The most frequently predicted stroke outcomes were mortality (7 studies) and functional outcome (5 studies). The most commonly used ML methods were random forests (9 studies), support vector machines (8 studies), decision trees (6 studies), and neural networks (6 studies). The median sample size was 475 (range 70-3184), with a median of 22 predictors (range 4-152) considered. All studies evaluated discrimination with thirteen using area under the ROC curve whilst calibration was assessed in three. Two studies performed external validation. None described the final model sufficiently well to reproduce it.ConclusionsThe use of ML for predicting stroke outcomes is increasing. However, few met basic reporting standards for clinical prediction tools and none made their models available in a way which could be used or evaluated. Major improvements in ML study conduct and reporting are needed before it can meaningfully be considered for practice

Young people’s priorities for the self-management of distress after stoma surgery due to inflammatory bowel disease: a consensus study using online nominal group technique

Abstract Introduction: The aim of this study was to gain consensus among young people with a stoma due to inflammatory bowel disease (IBD) on the priorities for the content of an intervention for the self-management of stoma-related distress. The current identification and management of distress in young people with a stoma is often sub-optimal in clinical settings and there is a need for improved support resources.Methods: Two consensus group meetings were carried out via online video conferencing, using Nominal Group Technique. Participants generated, rated on a Likert scale and discussed, topics for inclusion in a future self-management intervention.Results: Nineteen young people, aged 19-33, with a stoma due to IBD took part in one of two group meetings. Participants were located across England, Scotland, and Northern Ireland. Twenty-nine topics were generated by participants, seven of which reached consensus of &gt;80%, that is, a mean of &gt;5.6 on a 7-point Likert scale. These were: receiving advice from young people with lived experience of stoma surgery; advice on/ addressing concerns about romantic relationships, sex and intimacy; information about fertility and pregnancy related to stoma surgery; stoma ‘hacks’, e.g. useful everyday tips regarding clothing, making bag changes easier etc.; reflecting on and recognising own emotional response to surgery; tips on managing the stoma during the night; and processing trauma related to the illness and surgery journey.Conclusions: Findings extend previous research on young people’s experiences of stoma surgery, by generating consensus on young peoples’ priorities for managing distress related to surgery and living with a stoma. These priorities include topics not previously reported in the literature, including the need for information about fertility and pregnancy. Findings will inform the development of a self-management resource for young people with an IBD stoma and have relevance for the clinical management of stoma-related distress in this population.<br/

Associations Between 30-Day Mortality, Specialist Nursing, and Daily Physician Ward Rounds in a National Stroke Registry

Background and Purpose- Well-organized stroke care is associated with better patient outcomes, but the most important organizational factors are unknown. Methods- Data were extracted from the Sentinel Stroke National Audit Programme of adults with acute stroke treated in stroke hospitals in England and Wales between April 2013 and March 2015. Multilevel models with random intercepts for hospitals were used to estimate the association of each variable with 30-day mortality to estimate the impact of admission to differently organized hospitals. Results- Of the 143 578 patients with acute stroke admitted to 154 hospitals, 14.4% died within 30 days of admission. In adjusted analyses, admission to hospitals with higher ratios of nurses trained in swallow screening was associated with reduced odds of death ( P=0.004), and admission to hospitals with daily physician ward rounds was associated with 10% lower odds of mortality compared with less-frequent ward rounds (95% CI, 0.82-0.98; P=0.013). Number of stroke admissions and overall ratio of registered nurses on duty at weekends were not found to be independently associated with mortality after adjustment for other factors. Conclusions- If these associations are causal, an extra 1332 deaths annually in England and Wales could be saved by hospitals providing care associated with a ratio of nurses trained in swallow screening of at least 3 per 10 beds and daily stroke physician ward rounds

Earthquake Input Motions and Seismic Site Response in a Centrifuge Test Examining SFSI Effects

This paper describes the ground motion selection process and reports observed seismic site response and SFSI effects during a dynamic centrifuge test (Test-1). The centrifuge test is the first in a series of tests examining the effects of SFSI in dense urban environments. The objective of Test-1 is to examine SFSI effects for two structures that are located a significant distance apart and essentially isolated. The model structures represent a three-story building founded on spread footings and a nine-story structure founded on a threestory basement. The structures are sited on a dry, dense bed of Nevada Sand. The centrifuge model is subjected to a series of shaking events that represent near-fault and “ordinary” ground motions at a site in Los Angeles. Results show that site periods degrade as ground motion intensity increases with more pronounced degradation observed for near-fault ground motions as compared with ordinary ground motions. Additionally, the results indicate the importance of kinematic effects of embedded structures when considering SFSI effects