226 research outputs found

    Difficult at dusk? Illuminating the debate on cricket ball visibility

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    Objectives: Investigate the visibility of new and old red, white and pink cricket balls under lighting and background conditions experienced during a day–night cricket match. Design: We modelled the luminance contrast signals available for a typical observer for a ball against backgrounds in a professional cricket ground, at different times of day. Methods: Spectral reflectance (light reflected as a function of wavelength) was derived from laboratory measurements of new and old red, white and pink balls. We also gathered spectral measurements from backgrounds (pitch, grass, sightscreens, crowd, sky) and spectral illuminance during a day–night match (natural afternoon light, through dusk to night under floodlights) from Lord's Cricket Ground (London, UK). The luminance contrast of the ball relative to the background was calculated for each combination of ball, time of day, and background surface. Results: Old red and old pink balls may offer little or no contrast against the grass, pitch and crowd. New pink balls can also be of low contrast against the crowd at dusk, as can pink and white balls (of any age) against the sky at dusk. Conclusions: Reports of difficulties with visibility of the pink ball are supported by our data. However, our modelling also shows that difficulties with visibility may also be expected under certain circumstances for red and white balls. The variable conditions in a cricket ground and the changing colour of an ageing ball make maintaining good visibility of the ball a challenge when playing day–night matches

    A low-cost 2-D video system can accurately and reliably assess adaptive gait kinematics in healthy and low vision subjects

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    3-D gait analysis is the gold standard but many healthcare clinics and research institutes would benefit from a system that is inexpensive and simple but just as accurate. The present study examines whether a low-cost 2-D motion capture system can accurately and reliably assess adaptive gait kinematics in subjects with central vision loss, older controls, and younger controls. Subjects were requested to walk up and step over a 10 cm high obstacle that was positioned in the middle of a 4.5 m walkway. Four trials were simultaneously recorded with the Vicon motion capture system (3-D system) and a video camera that was positioned perpendicular to the obstacle (2-D system). The kinematic parameters (crossing height, crossing velocity, foot placement, single support time) were calculated offline. Strong Pearson's correlations were found between the two systems for all parameters (average r = 0.944, all p < 0.001). Bland-Altman analysis showed that the agreement between the two systems was good in all three groups after correcting for systematic biases related to the 2-D marker positions. The test-retest reliability for both systems was high (average ICC = 0.959). These results show that a low-cost 2-D video system can reliably and accurately assess adaptive gait kinematics in healthy and low vision subjects

    When Is Visual Information Used to Control Locomotion When Descending a Kerb?

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    YesBackground: Descending kerbs during locomotion involves the regulation of appropriate foot placement before the kerb-edge and foot clearance over it. It also involves the modulation of gait output to ensure the body-mass is safely and smoothly lowered to the new level. Previous research has shown that vision is used in such adaptive gait tasks for feedforward planning, with vision from the lower visual field (lvf) used for online updating. The present study determined when lvf information is used to control/update locomotion when stepping from a kerb. Methodology/Principal Findings: 12 young adults stepped down a kerb during ongoing gait. Force sensitive resistors (attached to participants' feet) interfaced with an high-speed PDLC 'smart glass' sheet, allowed the lvf to be unpredictably occluded at either heel-contact of the penultimate or final step before the kerb-edge up to contact with the lower level. Analysis focussed on determining changes in foot placement distance before the kerb-edge, clearance over it, and in kinematic measures of the step down. Lvf occlusion from the instant of final step contact had no significant effect on any dependant variable (p>0.09). Occlusion of the lvf from the instant of penultimate step contact had a significant effect on foot clearance and on several kinematic measures, with findings consistent with participants becoming uncertain regarding relative horizontal location of the kerb-edge. Conclusion/Significance: These findings suggest concurrent feedback of the lower limb, kerb-edge, and/or floor area immediately in front/below the kerb is not used when stepping from a kerb during ongoing gait. Instead heel-clearance and pre-landing-kinematic parameters are determined/planned using lvf information acquired in the penultimate step during the approach to the kerb-edge, with information related to foot placement before the kerb-edge being the most salient

    The Use of Novel Oral Anti-Coagulant's (NOAC) compared to Vitamin K Antagonists (Warfarin) in patients with Left Ventricular thrombus after Acute Myocardial Infarction (AMI).

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    This is a pre-copyedited, author-produced version of an article accepted for publication in European Heart Journal - Cardiovascular Pharmacotherapy following peer review. The version of record: Daniel A Jones, Paul Wright, Momin A Alizadeh, Sadeer Fhadil, Krishnaraj S Rathod, Oliver Guttmann, Charles Knight, Adam Timmis, Andreas Baumbach, Andrew Wragg, Anthony Mathur, Sotiris Antoniou, The Use of Novel Oral Anti-Coagulant’s (NOAC) compared to Vitamin K Antagonists (Warfarin) in patients with Left Ventricular thrombus after Acute Myocardial Infarction (AMI), European Heart Journal - Cardiovascular Pharmacotherapy, pvaa096, https://doi.org/10.1093/ehjcvp/pvaa096AIM: Current guidelines recommend the use of Vitamin K Antagonist (VKA) for up to 3 - 6 months for treatment of LV thrombus post-acute myocardial infarction (AMI). However, based on evidence supporting non-inferiority of Novel Oral Anti-Coagulant's (NOAC) compared to VKA for other indications such as DVT, PE and thrombo-embolic prevention in atrial fibrillation, NOACs are being increasingly used off licence for the treatment of LV thrombus post AMI. In this study we investigated the safety and effect of NOACs compared to VKA on LV thrombus resolution in patients presenting with AMI. METHODS AND RESULTS: This was an observational study of 2,328 consecutive patients undergoing Coronary Angiography +/- Percutaneous Coronary Intervention (PCI) for AMI between May 2015- December 2018, at a UK cardiac centre. Patients' details were collected from the hospital electronic database. The primary end-point was rate of LV thrombus resolution with bleeding rates a secondary outcome.Left ventricular (LV) thrombus was diagnosed in 101 (4.3%) patients. Sixty patients (59.4%) were started on VKA and 41 patients (40.6%) on NOAC therapy (rivaroxaban: 58.5%, apixaban, 36.5% and edoxaban: 5.0%). Both groups were well matched in terms of baseline characteristics including age, previous cardiac history (Previous MI, PCI, CABG), and cardiovascular risk factors (Hypertension, Diabetes, Hypercholesterolaemia).Over the follow up period (median 2.2 years), overall rates of LV thrombus resolution were 86.1%. There was greater and earlier LV thrombus resolution in the NOAC group compared to patients treated with warfarin (82% vs 64.4%, p = 0.0018, at 1 year), which persisted after adjusting for baseline variables (OR 1.8 95% CI 1.2-2.9). Major bleeding events during the f/u period were lower in the NOAC group, compared with VKA group (0% vs 6.7%, p = 0.030) with no difference in rates of systemic thromboembolism (5% vs 2.4%, p = 0.388). CONCLUSION: This data suggests improved thrombus resolution in post ACS LV thrombosis in patients treated with NOACs compared to vitamin K antagonists. This improvement in thrombus resolution was accompanied with a better safety profile for NOAC patients' vs VKA treated patients. Thus, provides data to support a randomised trial to answer this question

    Impact of Coronavirus Disease 2019 Pandemic on the Incidence and Management of Out‐of‐Hospital Cardiac Arrest in Patients Presenting With Acute Myocardial Infarction in England

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    Background: Studies have reported significant reduction in acute myocardial infarction–related hospitalizations during the coronavirus disease 2019 (COVID‐19) pandemic. However, whether these trends are associated with increased incidence of out‐of‐hospital cardiac arrest (OHCA) in this population is unknown. / Methods and Results: Acute myocardial infarction hospitalizations with OHCA during the COVID‐19 period (February 1–May 14, 2020) from the Myocardial Ischaemia National Audit Project and British Cardiovascular Intervention Society data sets were analyzed. Temporal trends were assessed using Poisson models with equivalent pre–COVID‐19 period (February 1–May 14, 2019) as reference. Acute myocardial infarction hospitalizations during COVID‐19 period were reduced by >50% (n=20 310 versus n=9325). OHCA was more prevalent during the COVID‐19 period compared with the pre–COVID‐19 period (5.6% versus 3.6%), with a 56% increase in the incidence of OHCA (incidence rate ratio, 1.56; 95% CI, 1.39–1.74). Patients experiencing OHCA during COVID‐19 period were likely to be older, likely to be women, likely to be of Asian ethnicity, and more likely to present with ST‐segment–elevation myocardial infarction. The overall rates of invasive coronary angiography (58.4% versus 71.6%; P<0.001) were significantly lower among the OHCA group during COVID‐19 period with increased time to reperfusion (mean, 2.1 versus 1.1 hours; P=0.05) in those with ST‐segment–elevation myocardial infarction. The adjusted in‐hospital mortality probability increased from 27.7% in February 2020 to 35.8% in May 2020 in the COVID‐19 group (P<.001). / Conclusions: In this national cohort of hospitalized patients with acute myocardial infarction, we observed a significant increase in incidence of OHCA during COVID‐19 period paralleled with reduced access to guideline‐recommended care and increased in‐hospital mortality

    Outcomes of COVID-19-positive acute coronary syndrome patients: A multisource electronic healthcare records study from England

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    Background: Patients with underlying cardiovascular disease and coronavirus disease 2019 (COVID-19) infection are at increased risk of morbidity and mortality. Objectives: This study was designed to characterize the presenting profile and outcomes of patients hospitalized with acute coronary syndrome (ACS) and COVID-19 infection. Methods: This observational cohort study was conducted using multisource data from all acute NHS hospitals in England. All consecutive patients hospitalized with diagnosis of ACS with or without COVID-19 infection between 1 March and 31 May 2020 were included. The primary outcome was in-hospital and 30-day mortality. Results: A total of 12 958 patients were hospitalized with ACS during the study period, of which 517 (4.0%) were COVID-19-positive and were more likely to present with non-ST-elevation acute myocardial infarction. The COVID-19 ACS group were generally older, Black Asian and Minority ethnicity, more comorbid and had unfavourable presenting clinical characteristics such as elevated cardiac troponin, pulmonary oedema, cardiogenic shock and poor left ventricular systolic function compared with the non-COVID-19 ACS group. They were less likely to receive an invasive coronary angiography (67.7% vs 81.0%), percutaneous coronary intervention (PCI) (30.2% vs 53.9%) and dual antiplatelet medication (76.3% vs 88.0%). After adjusting for all the baseline differences, patients with COVID-19 ACS had higher in-hospital (adjusted odds ratio (aOR): 3.27; 95% confidence interval (CI): 2.41–4.42) and 30-day mortality (aOR: 6.53; 95% CI: 5.1–8.36) compared to patients with the non-COVID-19 ACS. Conclusion: COVID-19 infection was present in 4% of patients hospitalized with an ACS in England and is associated with lower rates of guideline-recommended treatment and significant mortality hazard

    Evaluating the Quality of Research into a Single Prognostic Biomarker: A Systematic Review and Meta-analysis of 83 Studies of C-Reactive Protein in Stable Coronary Artery Disease

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    Background Systematic evaluations of the quality of research on a single prognostic biomarker are rare. We sought to evaluate the quality of prognostic research evidence for the association of C-reactive protein (CRP) with fatal and nonfatal events among patients with stable coronary disease. Methods and Findings We searched MEDLINE (1966 to 2009) and EMBASE (1980 to 2009) and selected prospective studies of patients with stable coronary disease, reporting a relative risk for the association of CRP with death and nonfatal cardiovascular events. We included 83 studies, reporting 61,684 patients and 6,485 outcome events. No study reported a prespecified statistical analysis protocol; only two studies reported the time elapsed (in months or years) between initial presentation of symptomatic coronary disease and inclusion in the study. Studies reported a median of seven items (of 17) from the REMARK reporting guidelines, with no evidence of change over time. The pooled relative risk for the top versus bottom third of CRP distribution was 1.97 (95% confidence interval [CI] 1.78–2.17), with substantial heterogeneity (I2 = 79.5). Only 13 studies adjusted for conventional risk factors (age, sex, smoking, obesity, diabetes, and low-density lipoprotein [LDL] cholesterol) and these had a relative risk of 1.65 (95% CI 1.39–1.96), I2 = 33.7. Studies reported ten different ways of comparing CRP values, with weaker relative risks for those based on continuous measures. Adjusting for publication bias (for which there was strong evidence, Egger's p<0.001) using a validated method reduced the relative risk to 1.19 (95% CI 1.13–1.25). Only two studies reported a measure of discrimination (c-statistic). In 20 studies the detection rate for subsequent events could be calculated and was 31% for a 10% false positive rate, and the calculated pooled c-statistic was 0.61 (0.57–0.66). Conclusion Multiple types of reporting bias, and publication bias, make the magnitude of any independent association between CRP and prognosis among patients with stable coronary disease sufficiently uncertain that no clinical practice recommendations can be made. Publication of prespecified statistical analytic protocols and prospective registration of studies, among other measures, might help improve the quality of prognostic biomarker research

    Acute heart failure presentation, management, and outcomes in cancer patients: a national longitudinal study

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    AIMS: Currently, little evidence exists on survival and quality of care in cancer patients presenting with acute heart failure (HF). The aim of the study is to investigate the presentation and outcomes of hospital admission with acute HF in a national cohort of patients with prior cancer. METHODS AND RESULTS: This retrospective, population-based cohort study identified 221 953 patients admitted to a hospital in England for HF during 2012–2018 (12 867 with a breast, prostate, colorectal, or lung cancer diagnosis in the previous 10 years). We examined the impact of cancer on (i) HF presentation and in-hospital mortality, (ii) place of care, (iii) HF medication prescribing, and (iv) post-discharge survival, using propensity score weighting and model-based adjustment. Heart failure presentation was similar between cancer and non-cancer patients. A lower percentage of patients with prior cancer were cared for in a cardiology ward [−2.4% age point difference (ppd) (95% CI −3.3, −1.6)] or were prescribed angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists (ACEi/ARB) for heart failure with reduced ejection fraction [−2.1 ppd (−3.3, −0.9)] than non-cancer patients. Survival after HF discharge was poor with median survival of 1.6 years in prior cancer and 2.6 years in non-cancer patients. Mortality in prior cancer patients was driven primarily by non-cancer causes (68% of post-discharge deaths). CONCLUSION: Survival in prior cancer patients presenting with acute HF was poor, with a significant proportion due to non-cancer causes of death. Despite this, cardiologists were less likely to manage cancer patients with HF. Cancer patients who develop HF were less likely to be prescribed guideline-based HF medications compared with non-cancer patients. This was particularly driven by patients with a poorer cancer prognosis

    Instability of Plastid DNA in the Nuclear Genome

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    Functional gene transfer from the plastid (chloroplast) and mitochondrial genomes to the nucleus has been an important driving force in eukaryotic evolution. Non-functional DNA transfer is far more frequent, and the frequency of such transfers from the plastid to the nucleus has been determined experimentally in tobacco using transplastomic lines containing, in their plastid genome, a kanamycin resistance gene (neo) readymade for nuclear expression. Contrary to expectations, non-Mendelian segregation of the kanamycin resistance phenotype is seen in progeny of some lines in which neo has been transferred to the nuclear genome. Here, we provide a detailed analysis of the instability of kanamycin resistance in nine of these lines, and we show that it is due to deletion of neo. Four lines showed instability with variation between progeny derived from different areas of the same plant, suggesting a loss of neo during somatic cell division. One line showed a consistent reduction in the proportion of kanamycin-resistant progeny, suggesting a loss of neo during meiosis, and the remaining four lines were relatively stable. To avoid genomic enlargement, the high frequency of plastid DNA integration into the nuclear genome necessitates a counterbalancing removal process. This is the first demonstration of such loss involving a high proportion of recent nuclear integrants. We propose that insertion, deletion, and rearrangement of plastid sequences in the nuclear genome are important evolutionary processes in the generation of novel nuclear genes. This work is also relevant in the context of transgenic plant research and crop production, because similar processes to those described here may be involved in the loss of plant transgenes
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