137 research outputs found
Passive superresolution imaging of incoherent objects
We investigate Hermite Gaussian Imaging (HGI) -- a novel passive
super-resolution technique -- for complex 2D incoherent objects in the
sub-Rayleigh regime. The method consists of measuring the field's spatial mode
components in the image plane in the overcomplete basis of Hermite-Gaussian
modes and their superpositions and subsequently using a deep neural network to
reconstruct the object from these measurements. We show a three-fold resolution
improvement over direct imaging. Our HGI reconstruction retains its superiority
even if the same neural network is applied to improve the resolution of direct
imaging. This superiority is also preserved in the presence of shot noise. Our
findings are the first step towards passive super-resolution imaging protocols
in fluorescent microscopy and astronomy.Comment: 6 pages, 8 figure
Accuracy of clinical predictions of prognosis at the end-of-life: evidence from routinely collected data in urgent care records
BACKGROUND: The accuracy of prognostication has important implications for patients, families, and health services since it may be linked to clinical decision-making, patient experience and outcomes and resource allocation. Study aim is to evaluate the accuracy of temporal predictions of survival in patients with cancer, dementia, heart, or respiratory disease. METHODS: Accuracy of clinical prediction was evaluated using retrospective, observational cohort study of 98,187 individuals with a Coordinate My Care record, the Electronic Palliative Care Coordination System serving London, 2010-2020. The survival times of patients were summarised using median and interquartile ranges. Kaplan Meier survival curves were created to describe and compare survival across prognostic categories and disease trajectories. The extent of agreement between estimated and actual prognosis was quantified using linear weighted Kappa statistic. RESULTS: Overall, 3% were predicted to live "days"; 13% "weeks"; 28% "months"; and 56% "year/years". The agreement between estimated and actual prognosis using linear weighted Kappa statistic was highest for patients with dementia/frailty (0.75) and cancer (0.73). Clinicians' estimates were able to discriminate (log-rank p < 0.001) between groups of patients with differing survival prospects. Across all disease groups, the accuracy of survival estimates was high for patients who were likely to live for fewer than 14 days (74% accuracy) or for more than one year (83% accuracy), but less accurate at predicting survival of "weeks" or "months" (32% accuracy). CONCLUSION: Clinicians are good at identifying individuals who will die imminently and those who will live for much longer. The accuracy of prognostication for these time frames differs across major disease categories, but remains acceptable even in non-cancer patients, including patients with dementia. Advance Care Planning and timely access to palliative care based on individual patient needs may be beneficial for those where there is significant prognostic uncertainty; those who are neither imminently dying nor expected to live for "years"
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Effectiveness of web-based and mobile health interventions designed to enhance adherence to physical activity for people with inflammatory arthritis: a systematic review
Objective: The aim of this systematic review was to assess the evidence from randomized controlled trials (RCTs) and cohort studies for the effectiveness of digital interventions designed to enhance adherence to physical activity (PA) for people with inflammatory arthritis and describe the intervention content using established coding criteria.
Methods: Six electronic databases were searched for published and unpublished studies. Independent data extraction and quality assessment (Cochrane risk of bias II or ROBINS-I) were conducted by two reviewers. The primary outcome was self-reported adherence to PA post-intervention. Secondary outcomes included self-reported adherence to PA at other time points, level of PA or engagement with intervention at any follow-up time point. Intervention content was assessed using the Consensus on Exercise Reporting Template and the Behaviour Change Techniques Taxonomy version 1.
Results: From 11 136 citations, four moderate risk of bias studies (three RCTs and one cohort study) including 1160 participants with RA or JIA were identified. Owing to heterogeneity of outcomes, a narrative synthesis was conducted. Only one RCT reported a small between-group difference in adherence to PA [mean difference (95% CI) -0.46 (-0.82, -0.09)] in favour of the intervention. There were no between-group differences in any secondary outcomes. Interventions included between 3 and 11 behaviour change techniques but provided minimal information on exercise prescription.
Conclusion: There is currently limited moderate-quality evidence available to provide confident evaluation of the effect of web-based and mobile health interventions on adherence to PA or level of PA post-intervention in people with inflammatory arthritis
Synthesis of guidance available for assessing methodological quality and grading of evidence from qualitative research to inform clinical recommendations: a systematic literature review
Objective To understand (1) what guidance exists to assess the methodological quality of qualitative research; (2) what methods exist to grade levels of evidence from qualitative research to inform recommendations within European Alliance of Associations for Rheumatology (EULAR). Methods A systematic literature review was performed in multiple databases including PubMed/Medline, EMBASE, Web of Science, COCHRANE and PsycINFO, from inception to 23 October 2020. Eligible studies included primary articles and guideline documents available in English, describing the: (1) development; (2) application of validated tools (eg, checklists); (3) guidance on assessing methodological quality of qualitative research and (4) guidance on grading levels of qualitative evidence. A narrative synthesis was conducted to identify key similarities between included studies. Results Of 9073 records retrieved, 51 went through to full-manuscript review, with 15 selected for inclusion. Six articles described methodological tools to assess the quality of qualitative research. The tools evaluated research design, recruitment, ethical rigour, data collection and analysis. Seven articles described one approach, focusing on four key components to determine how much confidence to place in findings from systematic reviews of qualitative research. Two articles focused on grading levels of clinical recommendations based on qualitative evidence; one described a qualitative evidence hierarchy, and another a research pyramid. Conclusion There is a lack of consensus on the use of tools, checklists and approaches suitable for appraising the methodological quality of qualitative research and the grading of qualitative evidence to inform clinical practice. This work is expected to facilitate the inclusion of qualitative evidence in the process of developing recommendations at EULAR level
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Linkage between fitness of yeast cells and adenylate kinase catalysis
Enzymes have evolved with highly specific values of their catalytic parameters kcat and KM. This poses fundamental biological questions about the selection pressures responsible for evolutionary tuning of these parameters. Here we are address these questions for the enzyme adenylate kinase (Adk) in eukaryotic yeast cells. A plasmid shuffling system was developed to allow quantification of relative fitness (calculated from growth rates) of yeast in response to perturbations of Adk activity introduced through mutations. Biophysical characterization verified that all variants studied were properly folded and that the mutations did not cause any substantial differences to thermal stability. We found that cytosolic Adk is essential for yeast viability in our strain background and that viability could not be restored with a catalytically dead, although properly folded Adk variant. There exist a massive overcapacity of Adk catalytic activity and only 12% of the wild type kcat is required for optimal growth at the stress condition 20°C. In summary, the approach developed here has provided new insights into the evolutionary tuning of kcat for Adk in a eukaryotic organism. The developed methodology may also become useful for uncovering new aspects of active site dynamics and also in enzyme design since a large library of enzyme variants can be screened rapidly by identifying viable colonies
Preparation of selective and segmentally labeled single-stranded DNA for NMR by self-primed PCR and asymmetrical endonuclease double digestion
We demonstrate a new, efficient and easy-to-use method for enzymatic synthesis of (stereo-)specific and segmental 13C/15N/2H isotope-labeled single-stranded DNA in amounts sufficient for NMR, based on the highly efficient self-primed PCR. To achieve this, new approaches are introduced and combined. (i) Asymmetric endonuclease double digestion of tandem-repeated PCR product. (ii) T4 DNA ligase mediated ligation of two ssDNA segments. (iii) In vitro dNTP synthesis, consisting of in vitro rNTP synthesis followed by enzymatic stereo-selective reduction of the C2′ of the rNTP, and a one-pot add-up synthesis of dTTP from dUTP. The method is demonstrated on two ssDNAs: (i) a 36-nt three-way junction, selectively 13C9/15N3/2H(1′,2″,3′,4′,5′,5″)-dC labeled and (ii) a 39-nt triple-repeat three-way junction, selectively 13C9/15N3/2H(1′,2″,3′,4′,5′,5″)-dC and 13C9/15N2/2H(1′,2″,3′,4′,5′,5″)-dT labeled in segment C20-C39. Their NMR spectra show the spectral simplification, while the stereo-selective 2H-labeling in the deoxyribose of the dC-residues, straightforwardly provided assignment of their C1′–H2′ and C2′–H2′ resonances. The labeling protocols can be extended to larger ssDNA molecules and to more than two segments
Global, regional, and national burden of low back pain, 1990–2020, its attributable risk factors, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021
Background: Low back pain is highly prevalent and the main cause of years lived with disability (YLDs). We present the most up-to-date global, regional, and national data on prevalence and YLDs for low back pain from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021. Methods: Population-based studies from 1980 to 2019 identified in a systematic review, international surveys, US medical claims data, and dataset contributions by collaborators were used to estimate the prevalence and YLDs for low back pain from 1990 to 2020, for 204 countries and territories. Low back pain was defined as pain between the 12th ribs and the gluteal folds that lasted a day or more; input data using alternative definitions were adjusted in a network meta-regression analysis. Nested Bayesian meta-regression models were used to estimate prevalence and YLDs by age, sex, year, and location. Prevalence was projected to 2050 by running a regression on prevalence rates using Socio-demographic Index as a predictor, then multiplying them by projected population estimates. Findings: In 2020, low back pain affected 619 million (95% uncertainty interval 554–694) people globally, with a projection of 843 million (759–933) prevalent cases by 2050. In 2020, the global age-standardised rate of YLDs was 832 per 100 000 (578–1070). Between 1990 and 2020, age-standardised rates of prevalence and YLDs decreased by 10·4% (10·9–10·0) and 10·5% (11·1–10·0), respectively. A total of 38·8% (28·7–47·0) of YLDs were attributed to occupational factors, smoking, and high BMI. Interpretation: Low back pain remains the leading cause of YLDs globally, and in 2020, there were more than half a billion prevalent cases of low back pain worldwide. While age-standardised rates have decreased modestly over the past three decades, it is projected that globally in 2050, more than 800 million people will have low back pain. Challenges persist in obtaining primary country-level data on low back pain, and there is an urgent need for more high-quality, primary, country-level data on both prevalence and severity distributions to improve accuracy and monitor change. Funding: Bill and Melinda Gates Foundation
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