57 research outputs found

    Sleep Insufficiency, Sleep Health Problems and Performance in High School Students

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    A survey on sleep schedule, sleep health, school performance and school start times was conducted in 1,941 adolescents. A high level of early and circadian-disadvantaged sleep/wake schedules during weekdays was observed. Shorter sleep duration on weekdays was reported, especially in upper classmen. Complaints of inadequate sleep and sleepiness during weekdays, alarm clock use, and napping were prevalent. Night awakening and prolonged sleep onset were common and associated with poor school performance. Students with a sleep length of less than 7 hours on both weekdays and weekends exhibited poorer performance, while those who made up this sleep loss on weekends did not. The total number of poor sleep factors in an individual also correlated with poor school performance. Earlier school start times were associated with a perception of poor sleep quality, shorter sleep duration and more sleep health problems. We conclude that sleep inadequacies and sleep health problems were prevalent in this population, especially in those who started school earlier in the morning, and that these poor sleep factors were associated with school performance

    Assessing the vulnerability to price spikes in agricultural commodity markets

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    We empirically examine the predictability of the conditions which are associated with a higher probability of a price spike in agricultural commodity markets. We find that the forward spread is the most significant indicator of probable price jumps in maize, wheat and soybeans futures markets, a result which is in line with the β€œTheory of Storage”. We additionally show that some option-implied variables add significant predictive power when added to the more standard information variable set. Overall, the estimated probabilities of large price increases from our probit models exhibit significant correlations with the historical sudden market upheavals in agricultural markets

    Surgery for complications of trans-catheter closure of atrial septal defects: a multi-institutional study from the European Congenital Heart Surgeons Association

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    Objective: This study aims to analyse the collective experience of participating European Congenital Heart Surgeons Association centres in the surgical management of complications resulting from trans-catheter closure of atrial septal defects (ASDs). Methods: The records of all (n=56) patients, aged 3-70 years (median 18 years), who underwent surgery for complications of trans-catheter ASD closure in 19 participating institutions over a 10-year period (1997-2007) were retrospectively reviewed. Risk factors for surgical complications were sought. Surgical outcomes were compared with those reported for primary surgical ASD closure in the European Association of Cardio-thoracic Surgery Congenital Database. Results: A wide range of ASD sizes (5-34mm) and devices of various types and sizes (range 12-60mm) were involved, including 13 devices less than 20mm. Complications leading to surgery included embolisation (n=29), thrombosis/thrombo-embolism/cerebral ischaemia or stroke (n=12), significant residual shunt (n=12), aortic or atrial perforation or erosion (n=9), haemopericardium with tamponade (n=5), aortic or mitral valve injury (n=2) and endocarditis (n=1). Surgery (39 early emergent and 17 late operations) involved device removal, repair of damaged structures and ASD closure. Late operations were needed 12 days to 8 years (median 3 years) after device implantation. There were three hospital deaths (mortality 5.4%). During the same time period, mortality for all 4453 surgical ASD closures reported in the European Association of Cardio-Thoracic Surgery Congenital Database was 0.36% (p=0.001). Conclusions: Trans-catheter device closure of ASDs, even in cases when small devices are used, can lead to significant complications requiring surgical intervention. Once a complication leading to surgery occurs, mortality is significantly greater than that of primary surgical ASD closure. Major complications can occur late after device placement. Therefore, lifelong follow-up of patients in whom ASDs have been closed by devices is mandator

    Surgery for anomalous aortic origin of coronary arteries : a multicentre study from the European Congenital Heart Surgeons Association

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    OBJECTIVES: We sought to describe early and late outcomes in a large surgical series of patients with anomalous aortic origin of coronary arteries. METHODS: We performed a retrospective multicentre study including surgical patients with anomalous aortic origin of coronary arteries since 1991. Patients with isolated high coronary takeoff and associated major congenital heart disease were excluded. RESULTS: We collected 156 surgical patients (median age 39.5 years, interquartile range 15-53) affected by anomalous right (67.9%), anomalous left (22.4%) and other anatomical abnormalities (9.6%). An interarterial course occurred in 86.5%, an intramural course in 62.8% and symptoms in 85.9%. The operations included coronary unroofing (56.4%), reimplantation (19.2%), coronary bypass graft (15.4%) and other (9.0%). Two patients with preoperative cardiac failure died postoperatively (1.3%). All survivors were discharged home in good clinical condition. At a median follow-up of 2 years (interquartile range 1-5, 88.5% complete), there were 3 deaths (2.2%), 9 reinterventions in 8 patients (5 interventional, 3 surgical); 91.2% are in New York Heart Association functional class CONCLUSIONS: Surgical repair of anomalous aortic origin of coronary arteries is effective and has few complications. Unroofing and coronary reimplantation are safe and are the most common procedures. The occurrence of late adverse events is not negligible, and long-term surveillance is mandatory. Most young athletes can return to an unrestrained lifestyle.Peer reviewe

    Anomalous aortic origin of coronary arteries : Early results on clinical management from an international multicenter study

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    Background: Anomalous aortic origin of coronary arteries (AAOCA) is a rare abnormality, whose optimal management is still undefined. We describe early outcomes in patients treated with different management strategies. Methods: This is a retrospective clinicalmulticenter study including patients with AAOCA, undergoing or not surgical treatment. Patients with isolated high coronary take off and associated major congenital heart disease were excluded. Preoperative, intraoperative, anatomical and postoperative data were retrieved from a common database. Results: Among 217 patients, 156 underwent Surgical repair (median age 39 years, IQR: 15-53), while 61 were Medical (median age 15 years, IQR: 8-52), inwhomAAOCA was incidentally diagnosed during screening or clinical evaluations. Surgical patients were more often symptomatic when compared to medical ones (87.2% vs 44.3%, p b 0.001). Coronary unroofing was the most frequent procedure (56.4%). Operative mortality was 1.3% (2 patients with preoperative severe heart failure). At a median follow up of 18 months (range 0.1-23 years), 89.9% of survivors are in NYHA Conclusions: Surgery for AAOCA is safe andwith low morbidity. When compared to Medical patients, who remain on exercise restriction and medical therapy, surgical patients have a benefit in terms of symptoms and return to normal life. Since the long term-risk of sudden cardiac death is still unknown, we currently recommend accurate long term surveillance in all patients with AAOCA. (C) 2019 The Authors. Published by Elsevier B.V.Peer reviewe

    Why Functional Pre-Erythrocytic and Bloodstage Malaria Vaccines Fail: A Meta-Analysis of Fully Protective Immunizations and Novel Immunological Model

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    Background: Clinically protective malaria vaccines consistently fail to protect adults and children in endemic settings, and at best only partially protect infants. Methodology/Principal Findings: We identify and evaluate 1916 immunization studies between 1965-February 2010, and exclude partially or nonprotective results to find 177 completely protective immunization experiments. Detailed reexamination reveals an unexpectedly mundane basis for selective vaccine failure: live malaria parasites in the skin inhibit vaccine function. We next show published molecular and cellular data support a testable, novel model where parasite-host interactions in the skin induce malaria-specific regulatory T cells, and subvert early antigen-specific immunity to parasite-specific immunotolerance. This ensures infection and tolerance to reinfection. Exposure to Plasmodium-infected mosquito bites therefore systematically triggers immunosuppression of endemic vaccine-elicited responses. The extensive vaccine trial data solidly substantiate this model experimentally. Conclusions/Significance: We conclude skinstage-initiated immunosuppression, unassociated with bloodstage parasites, systematically blocks vaccine function in the field. Our model exposes novel molecular and procedural strategies to significantly and quickly increase protective efficacy in both pipeline and currently ineffective malaria vaccines, and forces fundamental reassessment of central precepts determining vaccine development. This has major implications fo

    Isolation and partial characterization of the sialoglycoprotein fraction of murine erythrocyte ghosts

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    ABSTRACT With the lithium diiodosalicylate (LIS) extraction-phenol partition method, we have isolated a sialoglycoprotein fraction from DBA/2 mouse erythrocyte ghosts. We have demonstrated that the Laemmeli system for SDS PAGE can resolve this fraction into four monomers of which two (gp-2.1 and gp-3.1) appear to be authentic, whereas the other two (gp-2.2 and gp-3.2) are probably generated from gp-2.1 and gp-3.1, by limited proteolysis during the isolation procedure. All four components contain O-acetylated neuraminic acid residues, can be stained with Periodic acid-Schiff reagent (PAS) and with Coomassie Brilliant Blue (CB), and can be radioiodinated with the lactoperoxidase-glucose oxidase (LPO-GO) method. All monomers but especially gp-2.1 and gp-3.1 generate characteristic aggregates during solubilization in SDS. The aggregation is enhanced by boiling at high concentrations, and can be reversed by boiling at low concentrations. In addition, the fraction contains a diffuse component present also in ghosts which stains poorly with CB and with PAS and cannot be radioiodinated by the LPO-GO technique. SDS PAGE in the Steck and Yu gel system does not give an accurate separation of the sialoglycoprotein monomers. In our previous work on murine erythrocyte ghosts, we detecte

    A Low-Cost Algorithm for Uncertainty Quantification Simulations of Steady-State Flows: Application to Ocular Hemodynamics

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    An algorithm for the calculation of steady-state flowing under uncertain conditions is introduced in this work in order to obtain a probabilistic distribution of uncertain problem parameters. This is particularly important for problems with increased uncertainty, as typical deterministic methods are not able to fully describe all possible flow states of the problem. Standard methods, such as polynomial expansions and Monte Carlo simulations, are used for the formation of the generalized problem described by the incompressible Navier-Stokes equations. Since every realization of the uncertainty parameter space is coupled with non-linear terms, an incremental iterative procedure was adopted for the calculation. This algorithm adopts a Jacobi-like iteration methodology to decouple the equations and solve them one by one until there is overall convergence. The algorithm was tested in a typical artery geometry, including a bifurcation with an aneurysm, which consists of a well-documented biological flow test case. Additionally, its dependence on the uncertainty parameter space, i.e., the inlet velocity distribution, the Reynolds number variation, and parameters of the procedure, i.e., the number of polynomial expansions, was studied. Symmetry exists in probabilistic theories, similar to the one adopted by the present work. The results of the simulations conducted with the present algorithm are compared against the same but unsteady flow with a time-dependent inlet velocity profile, which represents a typical cardiac cycle. It was found that the present algorithm is able to correctly describe the flow field, as well as capture the upper and lower limits of the velocity field, which was made periodic. The comparison between the present algorithm and the typical unsteady one presented a maximum error of β‰ˆ2% in the common carotid area, while the error increased significantly inside the bifurcation area. Moreover, β€œsensitive” areas of the geometry with increased parameter uncertainty were identified, a result that is not possible to be obtained while using deterministic algorithms. Finally, the ability of the algorithm to tune the parameter limits was successfully tested
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