999 research outputs found
Controlled interfacial assembly of 2D curved colloidal crystals and jammed shells
Assembly of colloidal particles on fluid interfaces is a promising technique
for synthesizing two-dimensional micro-crystalline materials useful in fields
as diverse as biomedicine1, materials science2, mineral flotation3 and food
processing4. Current approaches rely on bulk emulsification methods, require
further chemical and thermal treatments, and are restrictive with respect to
the materials employed5-9. The development of methods that exploit the great
potential of interfacial assembly for producing tailored materials have been
hampered by the lack of understanding of the assembly process. Here we report a
microfluidic method that allows direct visualization and understanding of the
dynamics of colloidal crystal growth on curved interfaces. The crystals are
periodically ejected to form stable jammed shells, which we refer to as
colloidal armour. We propose that the energetic barriers to interfacial crystal
growth and organization can be overcome by targeted delivery of colloidal
particles through hydrodynamic flows. Our method allows an unprecedented degree
of control over armour composition, size and stability.Comment: 18 pages, 5 figure
High-Sensitivity Cardiac Troponin and the Universal Definition of Myocardial Infarction.
Background: The introduction of more sensitive cardiac troponin assays has led to increased recognition of myocardial injury in acute illnesses other than acute coronary syndrome. The Universal Definition of Myocardial Infarction recommends high-sensitivity cardiac troponin (hs-cTn) testing and classification of patients with myocardial injury based on aetiology, but the clinical implications of implementing this guideline are not well understood. Methods: In a stepped-wedge cluster randomized controlled trial, we implemented a hs-cTn assay and the recommendations of the Universal Definition in 48,282 consecutive patients with suspected acute coronary syndrome. In a pre-specified secondary analysis, we compared the primary outcome of myocardial infarction or cardiovascular death and secondary outcome of non-cardiovascular death at one year across diagnostic categories. Results: Implementation increased the diagnosis of type 1 myocardial infarction by 11% (510/4,471), type 2 myocardial infarction by 22% (205/916), and acute and chronic myocardial injury by 36% (443/1,233) and 43% (389/898), respectively. Compared to those without myocardial injury, the rate of the primary outcome was highest in those with type 1 myocardial infarction (cause-specific hazard ratio [csHR] 5.64, 95% confidence interval [CI] 5.12 to 6.22), but was similar across diagnostic categories, whereas non-cardiovascular deaths were highest in those with acute myocardial injury (csHR 2.65, 95%CI 2.33 to 3.01). Despite modest increases in anti-platelet therapy and coronary revascularization after implementation in patients with type 1 myocardial infarction, the primary outcome was unchanged (csHR 1.00, 95%CI 0.82 to 1.21). Increased recognition of type 2 myocardial infarction and myocardial injury did not lead to changes in investigation, treatment or outcomes. Conclusions: Implementation of high-sensitivity cardiac troponin and the recommendations of the Universal Definition of Myocardial Infarction identified patients at high-risk of cardiovascular and non-cardiovascular events, but was not associated with consistent increases in treatment or improved outcomes. Trials of secondary prevention are urgently required to determine whether this risk is modifiable in patients without type 1 myocardial infarction. Clinical Trial Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT0185212
Sex-Specific Thresholds of High-Sensitivity Troponin in Patients With Suspected Acute Coronary Syndrome.
BACKGROUND: Major disparities between women and men in the diagnosis, management, and outcomes of acute coronary syndrome are well recognized. OBJECTIVES: The aim of this study was to evaluate the impact of implementing a high-sensitivity cardiac troponin I assay with sex-specific diagnostic thresholds for myocardial infarction in women and men with suspected acute coronary syndrome. METHODS: Consecutive patients with suspected acute coronary syndrome were enrolled in a stepped-wedge, cluster-randomized controlled trial across 10 hospitals. Myocardial injury was defined as high-sensitivity cardiac troponin I concentration >99th centile of 16 ng/l in women and 34 ng/l in men. The primary outcome was recurrent myocardial infarction or cardiovascular death at 1 year. RESULTS: A total of 48,282 patients (47% women) were included. Use of the high-sensitivity cardiac troponin I assay with sex-specific thresholds increased myocardial injury in women by 42% and in men by 6%. Following implementation, women with myocardial injury remained less likely than men to undergo coronary revascularization (15% vs. 34%) and to receive dual antiplatelet (26% vs. 43%), statin (16% vs. 26%), or other preventive therapies (p < 0.001 for all). The primary outcome occurred in 18% (369 of 2,072) and 17% (488 of 2,919) of women with myocardial injury before and after implementation, respectively (adjusted hazard ratio: 1.11; 95% confidence interval: 0.92 to 1.33), compared with 18% (370 of 2,044) and 15% (513 of 3,325) of men (adjusted hazard ratio: 0.85; 95% confidence interval: 0.71 to 1.01). CONCLUSIONS: Use of sex-specific thresholds identified 5 times more additional women than men with myocardial injury. Despite this increase, women received approximately one-half the number of treatments for coronary artery disease as men, and outcomes were not improved. (High-Sensitivity Troponin in the Evaluation of Patients With Acute Coronary Syndrome [High-STEACS]; NCT01852123)
Reaction rates and transport in neutron stars
Understanding signals from neutron stars requires knowledge about the
transport inside the star. We review the transport properties and the
underlying reaction rates of dense hadronic and quark matter in the crust and
the core of neutron stars and point out open problems and future directions.Comment: 74 pages; commissioned for the book "Physics and Astrophysics of
Neutron Stars", NewCompStar COST Action MP1304; version 3: minor changes,
references updated, overview graphic added in the introduction, improvements
in Sec IV.A.
Renal artery stenosis-when to screen, what to stent?
Renal artery stensosis (RAS) continues to be a problem for clinicians, with no clear consensus on how to investigate and assess the clinical significance of stenotic lesions and manage the findings. RAS caused by fibromuscular dysplasia is probably commoner than previously appreciated, should be actively looked for in younger hypertensive patients and can be managed successfully with angioplasty. Atheromatous RAS is associated with increased incidence of cardiovascular events and increased cardiovascular mortality, and is likely to be seen with increasing frequency. Evidence from large clinical trials has led clinicians away from recommending interventional revascularisation towards aggressive medical management. There is now interest in looking more closely at patient selection for intervention, with focus on intervening only in patients with the highest-risk presentations such as flash pulmonary oedema, rapidly declining renal function and severe resistant hypertension. The potential benefits in terms of improving hard cardiovascular outcomes may outweigh the risks of intervention in this group, and further research is needed
A novel signalling screen demonstrates that CALR mutations activate essential MAPK signalling and facilitate megakaryocyte differentiation.
Most MPN patients lacking JAK2 mutations harbour somatic CALR mutations that are thought to activate cytokine signalling although the mechanism is unclear. To identify kinases important for survival of CALR-mutant cells we developed a novel strategy (KISMET) which utilises the full range of kinase selectivity data available from each inhibitor and thus takes advantage of off-target noise that limits conventional siRNA or inhibitor screens. KISMET successfully identified known essential kinases in haematopoietic and non-haematopoietic cell lines and identified the MAPK pathway as required for growth of the CALR-mutated MARIMO cells. Expression of mutant CALR in murine or human haematopoietic cell lines was accompanied by MPL-dependent activation of MAPK signalling, and MPN patients with CALR mutations showed increased MAPK activity in CD34-cells, platelets and megakaryocytes. Although CALR mutations resulted in protein instability and proteosomal degradation, mutant CALR was able to enhance megakaryopoiesis and pro-platelet production from human CD34+ progenitors. These data link aberrant MAPK activation to the MPN phenotype and identify it as a potential therapeutic target in CALR-mutant positive MPNs.Leukemia accepted article preview online, 14 October 2016. doi:10.1038/leu.2016.280.Work in the Green lab is supported by Leukemia and Lymphoma Research, Cancer Research UK, the NIHR Cambridge Biomedical Research Centre, the Cambridge Experimental Cancer Medicine Centre and the Leukemia & Lymphoma Society of America. WW is supported by the Austrian Science Foundation (J 3578-B21). CGA is supported by Kay Kendall Leukaemia Fund clinical research fellowship. UM is supported by a Cancer Research UK Clinician Scientist Fellowship. Work in the Huntly lab is supported by the European Research Council, the MRC (UK), Bloodwise, the Cambridge NIHR funded BRC, KKLF and a WT/MRC Stem Cell centre grant. Work in the Green and Huntly Labs is supported by core support grants by the Wellcome Trust to the Cambridge Institute for Medical Research (100140/z/12/z) and Wellcome Trust-MRC Cambridge Stem Cell Institute (097922/Z/11/Z)
Factors influencing job preferences of health workers providing obstetric care : results from discrete choice experiments in Malawi, Mozambique and Tanzania
BACKGROUND: Task shifting from established health professionals to mid-level providers (MLPs) (professionals who undergo shorter training in specific procedures) is one key strategy for reducing maternal and neonatal deaths. This has resulted in a growth in cadre types providing obstetric care in low and middle-income countries. Little is known about the relative importance of the different factors in determining motivation and retention amongst these cadres. METHODS: This paper presents findings from large sample (1972 respondents) discrete choice experiments to examine the employment preferences of obstetric care workers across three east African countries. RESULTS: The strongest predictors of job choice were access to continuing professional development and the presence of functioning human resources management (transparent, accountable and consistent systems for staff support, supervision and appraisal). Consistent with similar works we find pay and allowances significantly positively related to utility, but financial rewards are not as fundamental a factor underlying employment preferences as many may have previously believed. Location (urban vs rural) had the smallest average effect on utility for job choice in all three countries. CONCLUSIONS: These findings are important in the context where efforts to address the human resources crisis have focused primarily on increasing salaries and incentives, as well as providing allowances to work in rural areas
Polymerase δ replicates both strands after homologous recombination-dependent fork restart
To maintain genetic stability DNA must be replicated only once and replication completed even when individual replication forks are inactivated. Because fork inactivation is common, the passive convergence of an adjacent fork is insufficient to rescue all inactive forks. Thus, eukaryotic cells have evolved homologous recombination-dependent mechanisms to restart persistent inactive forks. Completing DNA synthesis via Homologous Recombination Restarted Replication (HoRReR) ensures cell survival, but at a cost. One such cost is increased mutagenesis caused by HoRReR being more error prone than canonical replication. This increased error rate implies that the HoRReR mechanism is distinct from that of a canonical fork. Here we exploit the fission yeast Schizosaccharomyces pombe to demonstrate that a DNA sequence duplicated by HoRReR during S phase is replicated semi-conservatively, but that both the leading and lagging strands are synthesised by DNA polymerase delta
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