Numerical analysis of wet separation of particles by density differences

Wet particle separation is widely used in mineral processing and plastic recycling to separate mixtures of particulate materials into further usable fractions due to density differences. This work presents efforts aiming to numerically analyze the wet separation of particles with different densities. In the current study the discrete element method (DEM) is used for the solid phase while the smoothed particle hydrodynamics (SPH) is used for modeling of the liquid phase. The two phases are coupled by the use of a volume averaging technique. In the current study, simulations of spherical particle separation were performed. In these simulations, a set of generated particles with two different densities is dropped into a rectangular container filled with liquid. The results of simulations with two different mixtures of particles demonstrated how separation depends on the densities of particles.Comment: This manuscript was accepted for the publication in the conference proceedings of ICNAAM 2016 conferenc

The presence of infection-related antiphospholipid antibodies in infective endocarditis determines a major risk factor for embolic events

AbstractOBJECTIVESThe impact of infection-associated antiphospholipid antibodies (APA) on endothelial cell activation, blood coagulation and fibrinolysis was evaluated in patients with infective endocarditis with and without major embolic events.BACKGROUNDAn embolic event is a common and severe complication of infective endocarditis. Despite the fact that APAs are known to be associated with infectious diseases, their pathogenic role in infective endocarditis has not been clearly defined.METHODSThe relationship among the occurrence of major embolic events, echocardiographic vegetation size, endothelial cell activation, thrombin generation, fibrinolysis and APA was examined in 91 patients with definite infective endocarditis, including 26 patients with embolic events and 65 control subjects without embolic events.RESULTSOverall, 14.3% of patients exhibited elevated APA levels. Embolic events occurred more frequently in patients with elevated levels of APA than in patients without (61.5% vs. 23.1%; p = 0.008). Patients with elevated levels of APA showed higher levels of prothrombin-fragment F1+2 (p = 0.005), plasminogen-activator inhibitor 1 (p = 0.0002), von Willebrand factor (p = 0.002) and lower levels of activated protein C (p = 0.001) than patients with normal levels of APA. Thrombin generation and endothelial cell activation were both positively correlated with levels of APA. The occurrence of elevated APA levels was frequently associated with structural valve abnormalities (p = 0.01) and vegetations >1.3 cm (p = 0.002).CONCLUSIONSInfection-associated elevated APA levels in patients with infective endocarditis are related to endothelial cell activation, thrombin generation and impairment of fibrinolysis. This may contribute to the increased risk for major embolic events in these patients

Guideline-adherence regarding critical time intervals in the German Chest Pain Unit registry

Background: Since 2008, the German Cardiac Society certified 256 Chest Pain Units (CPUs). Little is known about adherence to recommended performance measures in patients with suspected acute coronary syndrome (ACS) presenting to CPUs. We investigated guideline-adherence regarding critical time intervals and selected performance measures in German Chest Pain Units. Methods: From 2008 to 2014, 23,804 consecutive patients with suspected ACS were prospectively enrolled in the Chest Pain Unit registry of the German Cardiac Society. Results: Median time from symptom onset to first medical contact was 2 h in patients with ST-elevation myocardial infarction (STEMI) and 4 h in patients with unstable angina and non-STEMI (NSTEMI). In patients with STEMI, median time from hospital admission to percutaneous coronary intervention (PCI) was 40 min and median time from first medical contact to PCI was 1 h 35 min. Primary PCI was performed in 94.7% of patients with STEMI, 70.0% of patients with NSTEMI and 37.4% of patients with unstable angina. PCI was performed during the first 24 h in 79.5% of patients with NSTEMI and the first 72 h in 89.0% of patients with unstable angina. Electrocardiograms were performed in 99.5% after a median of 6 min after admission and obtained within 10 min in 71%. Interestingly, 56.1% of patients were found to have non-ACS diagnoses, underlining the importance of access to additional diagnostic modalities including echocardiography, stress testing or computed tomography. Conclusions: Guideline-adherence regarding critical time intervals and primary PCI rates is good in German Chest Pain Units. More than half of patients admitted with suspected ACS had non-ACS diagnoses. Improvements in pre-hospital time delays through public awareness programmes are warranted

Gender differences in clinical presentation and 1-year outcomes in atrial fibrillation

Objectives Our objective was to examine gender differences in clinical presentation, management and prognosis of atrial fibrillation (AF) in a contemporary cohort. Methods In 6412 patients, 39.7% women, of the PREvention oF thromboembolic events – European Registry in Atrial Fibrillation, we examined gender differences in symptoms, risk factors, therapies and 1-year incidence of adverse outcomes. Results Men with AF were on average younger than women (mean±SD: 70.1±10.7 vs 74.1±9.7 years, p<0.0001). Women more frequently had at least one AF-related symptom at least occasionally compared with men (95.4% in women, 89.8% in men, p<0.0001). Prescription of oral anticoagulation was similar, with an increase of non-vitamin K antagonist oral anticoagulants from 5.9% to 12.6% in women and from 6.2% to 12.6% in men, p<0.0001 for both. Men were more frequently treated with electrical cardioversion and ablation (20.6% and 6.3%, respectively) than women (14.9% and 3.3%, respectively), p<0.0001. Women had 65% (OR: 0.35; 95% CI (0.22 to 0.56)) lower age-adjusted and country-adjusted odds of coronary revascularisation, 40% (OR: 0.60; (0.38 to 0.93)) lower odds of acute coronary syndrome and 20% (OR: 0.80; (0.68 to 0.96)) lower odds of heart failure at 1 year. There were no statistically significant gender differences in 1-year stroke/transient ischaemic attack/arterial thromboembolism and major bleeding events. Conclusion In a ‘real-world’ European AF registry, women were more symptomatic but less likely to receive invasive rhythm control therapy such as electrical cardioversion or ablation. Further study is needed to confirm that these differences do not disadvantage women with AF

Profound influence of different methods for determination of the ankle brachial index on the prevalence estimate of peripheral arterial disease

BACKGROUND: The ankle brachial index (ABI) is an efficient tool for objectively documenting the presence of lower extremity peripheral arterial disease (PAD). However, different methods exist for ABI calculation, which might result in varying PAD prevalence estimates. To address this question, we compared five different methods of ABI calculation using Doppler ultrasound in 6,880 consecutive, unselected primary care patients ≥65 years in the observational getABI study. METHODS: In all calculations, the average systolic pressure of the right and left brachial artery was used as the denominator (however, in case of discrepancies of ≥10 mmHg, the higher reading was used). As nominators, the following pressures were used: the highest arterial ankle pressure of each leg (method #1), the lowest pressure (#2), only the systolic pressure of the tibial posterior artery (#3), only the systolic pressure of the tibial anterior artery (#4), and the systolic pressure of the tibial posterior artery after exercise (#5). An ABI < 0.9 was regarded as evidence of PAD. RESULTS: The estimated prevalence of PAD was lowest using method #1 (18.0%) and highest using method #2 (34.5%), while the differences in methods #3–#5 were less pronounced. Method #1 resulted in the most accurate estimation of PAD prevalence in the general population. Using the different approaches, the odds ratio for the association of PAD and cardiovascular (CV) events varied between 1.7 and 2.2. CONCLUSION: The data demonstrate that different methods for ABI determination clearly affect the estimation of PAD prevalence, but not substantially the strength of the associations between PAD and CV events. Nonetheless, to achieve improved comparability among different studies, one mode of calculation should be universally applied, preferentially method #1

Positive Behavior Support Systems in a Rural West Texas Middle School

Positive Behavior Support (PBS) programs are being implemented in schools in the United States to support faculty, staff, and students. The purpose of this study was to evaluate a PBS system at a rural west Texas middle school to discover what improvements are necessary for district-wide implementation and sustainability. The study drew on Bandura\u27s social learning theory, which posits that people learn from each other through observation, imitation, and modeling. PBS systems provide the framework for exhibiting specific behavior expectations so students and teachers can get the most from their educational experiences. A program evaluation was completed using discipline data from 2008-2012 from the middle school, observations at the middle school, and archival campus improvement plan results from the campus needs assessment from 2012. The research instrument used to assess the information was a pre-established PBS evaluation system called the School-Wide Evaluation Tool (SET) designed for programmatic assessment. The SET assessment tool guided the evaluation of information gathered from 100 students, 15 teachers, and an administrative team survey to highlight the strengths and weaknesses of the PBS program in the school and district, identify necessary changes to improve its effectiveness, and determine how to best implement the system district-wide. These findings were used to inform a white paper outlining how to implement a successful program and how to maintain the program over time. This evaluation provided specific steps to strengthen each component of a PBS program to ensure school-wide application and sustainability. A positive social change is experienced by students, teachers, and parents by the enhancement of a PBS system that improves student behavior in the school and district

Antithrombotic Therapy after Acute Coronary Syndrome or PCI in Atrial Fibrillation

Appropriate antithrombotic regimens for patients with atrial fibrillation who have an acute coronary syndrome or have undergone percutaneous coronary intervention (PCI) are unclear.In an international trial with a two-by-two factorial design, we randomly assigned patients with atrial fibrillation who had an acute coronary syndrome or had undergone PCI and were planning to take a P2Y12 inhibitor to receive apixaban or a vitamin K antagonist and to receive aspirin or matching placebo for 6 months. The primary outcome was major or clinically relevant nonmajor bleeding. Secondary outcomes included death or hospitalization and a composite of ischemic events.Enrollment included 4614 patients from 33 countries. There were no significant interactions between the two randomization factors on the primary or secondary outcomes. Major or clinically relevant nonmajor bleeding was noted in 10.5% of the patients receiving apixaban, as compared with 14.7% of those receiving a vitamin K antagonist (hazard ratio, 0.69; 95% confidence interval [CI], 0.58 to 0.81; P<0.001 for both noninferiority and superiority), and in 16.1% of the patients receiving aspirin, as compared with 9.0% of those receiving placebo (hazard ratio, 1.89; 95% CI, 1.59 to 2.24; P<0.001). Patients in the apixaban group had a lower incidence of death or hospitalization than those in the vitamin K antagonist group (23.5% vs. 27.4%; hazard ratio, 0.83; 95% CI, 0.74 to 0.93; P = 0.002) and a similar incidence of ischemic events. Patients in the aspirin group had an incidence of death or hospitalization and of ischemic events that was similar to that in the placebo group.In patients with atrial fibrillation and a recent acute coronary syndrome or PCI treated with a P2Y12 inhibitor, an antithrombotic regimen that included apixaban, without aspirin, resulted in less bleeding and fewer hospitalizations without significant differences in the incidence of ischemic events than regimens that included a vitamin K antagonist, aspirin, or both. (Funded by Bristol-Myers Squibb and Pfizer; AUGUSTUS ClinicalTrials.gov number, NCT02415400.)

Slow magnetic relaxation of Dy adatoms with in-plane magnetic anisotropy on a two-dimensional electron gas

We report on the magnetic properties of Dy atoms adsorbed on the (001) surface of SrTiO3. X-ray magnetic circular dichroism reveals slow relaxation of the Dy magnetization on a time scale of about 800 s at 2.5 K, unusually associated with an easy-plane magnetic anisotropy. We attribute these properties to Dy atoms occupying hollow adsorption sites on the TiO2-terminated surface. Conversely, Ho atoms adsorbed on the same surface show paramagnetic behavior down to 2.5 K. With the help of atomic multiplet simulations and first-principles calculations, we establish that Dy populates also the top-O and bridge sites on the coexisting SrO-terminated surface. A simple magnetization relaxation model predicts these two sites to have an even longer magnetization lifetime than the hollow site. Moreover, the adsorption of Dy on the insulating SrTiO3 crystal leads, regardless of the surface termination, to the formation of a spin-polarized two-dimensional electron gas of Ti 3dxy character, together with an antiferromagnetic Dy-Ti coupling. Our findings support the feasibility of tuning the magnetic properties of the rare-earth atoms by acting on the substrate electronic gas with electric fields

Single-molecule imaging reveals the oligomeric state of functional TNFα-induced plasma membrane TNFR1 clusters in cells

Ligand-induced tumor necrosis factor receptor 1 (TNFR1) activation controls NF-ĸB (nuclear factor kappa-light-chain-enhancer of activated B-cells) signaling, cell proliferation, programmed cell death, and survival, and is crucially involved in inflammation, autoimmune disorders, and cancer progression. Despite the relevance of TNFR1 clustering for signaling, oligomerization of ligand-free and ligand-activated TNFR1 remains controversial. At present, models range from ligand-independent receptor pre-dimerization to ligand-induced oligomerization. Here, we used quantitative, single-molecule superresolution microscopy to study TNFR1 assembly directly in native cellular settings and at physiological cell surface abundance. In the absence of its ligand TNFα, TNFR1 assembled into monomeric and dimeric receptor units. Upon binding of TNFα, TNFR1 clustered predominantly into trimers but also into higher-order oligomers. A functional mutation in the pre-ligand assembly domain (PLAD) of TNFR1 resulted in only monomeric TNFR1, which exhibited impaired ligand binding. In contrast, a form of TNFR1 with a mutation in the ligand-binding CRD2 subdomain retained the monomer-to-dimer ratio of the unliganded wildtype TNFR1 but exhibited no ligand binding. These results underscore the importance of ligand-independent TNFR1 dimerization in NF-ĸB signaling

Antithrombotic management and outcomes of patients with atrial fibrillation treated with NOACs early at the time of market introduction:Main results from the PREFER in AF Prolongation Registry

International audienceAbstract The management of patients with atrial fibrillation (AF) has rapidly changed with increasing use of non-vitamin K antagonist oral anticoagulants (NOACs) and changes in the use of rhythm control therapy. The prevention of thromboembolic events European Registry in Atrial Fibrillation Prolongation Registry (PREFER Prolongation) enrolled consecutive patients with AF on NOACs between 2014 and 2016 in a multicentre, prospective, observational study with one-year follow-up, focusing on the time of introduction of NOACs. Overall, 3783 patients were enrolled, with follow-up information available in 3223 (85%). Mean age was 72.2 ± 9.4 years, 40% were women, mean CHA 2 DS 2 VASc score was 3.4 ± 1.6, and 2587 (88.6%) had a CHA 2 DS 2 VASc score ≥ 2. Rivaroxaban was used in half of patients, and dabigatran and apixaban were used in about a quarter of patients each; edoxaban was not available for use in Europe at the time. Major cardiovascular event rate was low: serious events occurred in 74 patients (84 events, 2%), including 24 strokes (1%), 62 major bleeds (2%), of which 30 were life-threatening (1%) and 3 intracranial (0.1%), and 28 acute coronary syndromes (1%). Mortality was 2%. Antiarrhythmic drugs were used in about 50% of patients, catheter ablation in 5%. Adverse events were low in this contemporary European cohort of unselected AF patients treated with NOACs already at the time of their first introduction, despite high thromboembolic risk