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Better time-resolved imaging of stent grafts in the ascending aorta and arch accounting for cardiac motion is necessary to understand device-related complications and endoleaks. This report describes dynamic time-resolved computed tomographic angiography (d-CTA) and its combination with electrocardiography gating (d-gated CTA) to image stent grafts in the ascending aorta and to characterize endoleaks more clearly.d-CTA involves multiple scans acquired at different time points along the contrast enhancement curve. d-Gated CTA involves concomitant electrocardiography gating in a predefined cardiac phase minimizing motion-induced artifacts.This report illustrates the utility of d-CTA and d-gated CTA in 2 clinical cases. d-CTA demonstrated a type 1A endoleak in a patient with an aortic arch aneurysm treated with total arch debranching and a thoracic stent graft. d-gated CTA demonstrated a type 1A endoleak in a patient with an ascending aortic pseudoaneurysm treated with aortic cuff placement.Dynamic, cardiac-gated CTA enables time-resolved angiographic imaging of the ascending aorta and arch without any cardiac motion-related artifacts. Such advanced imaging techniques help with better characterization of endoleaks after stent graft deployment in the ascending aorta and arch.

BackgroundWhether intraprocedural changes in left atrial pressure and Doppler Echocardiographic parameters are synergistic in predicting outcomes after mitral transcatheter edge-to-edge repair (TEER) is not currently known. We sought to evaluate real-time changes in invasive hemodynamics and non-invasive Doppler to develop intraprocedural profiles and assess their impact on clinical outcomes after TEER for MR.MethodsIntraprocedural changes in hemodynamics and Doppler flow with transesophageal echocardiography were assessed in 181 patients with significant MR (51.9% primary MR) undergoing TEER between 2014 and 2022. Independent predictors of the primary composite endpoint of 1-year mortality and heart failure hospitalization (HFH) were identified using multivariable Cox-regression. With receiver operating characteristic curve-derived thresholds for the predictors of the primary end-point, patients were stratified into hemodynamic profiles based on the number of predictors present, and their impact on outcomes was examined.ResultsMedian follow-up was 21.3 months (IQR:11.3-36.5), with 1-year mortality and HFH rates of 19.3% and 12.7%, respectively. Residual mean left atrial pressure (mLAP) [HR=1.073/mmHg (1.03-1.12)], a lesser degree of MR reduction [HR=0.65/grade (0.45-0.93)], and lesser increment in PV systolic time velocity integral (S-VTI) [HR=0.95/cm (0.91-0.99)] were independent predictors of 1-year mortality/HFH. MR reduction by 15mmHg (43.6%) were the most predictive thresholds. Optimal profile (0 predictors), Mixed (1 predictor) and Poor profile (≥2 predictors) were present in 28.7%, 39.2% and 32.0% of cases respectively. Two-year cumulative event-free survival was 60.1% overall, and higher in patients with optimal profile compared to mixed/poor groups (84.7% vs 55.5% vs 43.3%, P5mmHg [HR=2.32 (1.17-4.61)].ConclusionIntraprocedural hemodynamic profiling integrating changes in invasive hemodynamics and non-invasive doppler provide prognostic information in patients undergoing TEER and may provide real-time intraprocedural guidance to optimize long-term clinical outcomes.

Aortic arch aneurysms are a challenging clinical problem especially in high-risk patients. Open aortic arch replacement, even in the best of centers, carries significant risk of stroke or death in this high-risk population. Many high-risk patients are deemed inoperable and not offered repair. Branched and fenestrated thoracic endografts are currently undergoing clinical trials in the United States but are not yet commercially available. Many elderly and frail patients have significant brachiocephalic occlusive disease or anatomy excluding them for consideration for such clinical trials. These patients also present with acute aortic syndromes requiring urgent or emergent repair and are unable to participate in clinical trials due to the time required to have such devices available. Alternative endovascular therapies, including parallel stent grafts (including Chimneys, Snorkels and Periscopes) and physician modified thoracic endografts, have been used to treat such high-risk patients combined with commercially available thoracic endovascular aneurysm repair (TEVAR) devices. This paper aims to review the techniques and current reported outcomes from parallel stent grafts and physician modified devices used to treat high risk patients undergoing repair for aortic arch pathologies.

An abbreviated history of genetic evaluation in Merinos demonstrates the remarkable changes that have occurred over the past 50 years. The amount of information available from an increasing number of studs adopting detailed measurement and recording is enormous and much effort has been directed at encouraging selection practices in studs on the basis of this information. In the past we have relied on genetic gains made in the ram breeding sector to be transferred on average to ram buyers, after a lag, for the benefit of the industry. But ram buyers can markedly influence their productivity by being active participants in genetic evaluation rather than relying on gains trickling down on average from ram breeders. Strategies for commercial producers involving choice of ram breeder(s), effective use of breeding values for ram purchases, and on-farm selection and management in the commercial flock are canvassed.

Jet impingement in engineering applications is used because of the capacity to transport high levels of heat flux from a surface of interest for cooling purposes. Thus far, based on a vast database of experiments and numerical simulations, several correlations have been established for local and average heat transfer on target surfaces as functions of relevant fluid properties and geometric parameters. In addition to these correlations, significant efforts have been made to gain fundamental understanding of jet impingement in varying configurations. However, the physics governing heat transfer by jet impingement is conjectured and even unclear. Thus, this article collates and discusses recent advances in fluidic mechanisms underlying the heat transfer by submerged jet impingement on a convex surface. The fluid properties developed on a convex surface due to jet impingement with varied characteristics, including jet-to-target surface spacing, interchange their primary roles in heat transfer from/to a convex surface. Particularly, conjectures associated with relevant fluidic mechanisms that have been widely accepted, are confirmed, clarified, and corrected.

Objectives The aim of this study was to evaluate clinical characteristics, mechanisms of failure, and outcomes of transcatheter aortic valve replacement (TAVR) explantation. Background Surgical explantation following TAVR may be required for structural valve degeneration, paravalvular leak, infection, or other reasons. However, in-depth data on indications and outcomes are lacking. Methods Data from a multicenter, international registry (EXPLANT-TAVR) of patients who underwent TAVR explantation were reviewed retrospectively. Explantations performed during the same admission as initial TAVR were excluded. Clinical and echocardiographic outcomes were evaluated. Median follow-up duration was 6.7 months (interquartile range [IQR]: 1.0-18.8 months) after TAVR explantation and was 97.7% complete at 30 days and 86.1% complete at 1 year. Results From November 2009 to September 2020, 269 patients across 42 centers with a mean age of 72.7 ± 10.4 years underwent TAVR explantation. About one quarter (25.9%) were deemed low surgical risk at index TAVR, and median Society of Thoracic Surgeons risk at TAVR explantation was 5.6% (IQR: 3.2%-9.6%). The median time to explantation was 11.5 months (IQR: 4.0-32.4 months). Balloon-expandable and self-expanding or mechanically expandable valves accounted for 50.9% and 49.1%, respectively. Indications for explantation included endocarditis (43.1%), structural valve degeneration (20.1%), paravalvular leak (18.2%), and prosthesis-patient mismatch (10.8%). Redo TAVR was not feasible because of unfavorable anatomy in 26.8% of patients. Urgent or emergency cases were performed in 53.1% of patients, aortic root replacement in 13.4%, and 54.6% had concomitant cardiac procedures. Overall survival at last follow-up was 76.1%. In-hospital, 30-day, and 1-year mortality rates were 11.9%, 13.1%, and 28.5%, respectively, and stroke rates were 5.9%, 8.6%, and 18.7%, respectively. Conclusions The EXPLANT-TAVR registry reveals that surgical risks associated with TAVR explantation are not negligible and should be taken into consideration in the lifetime management of aortic stenosis.

Objectives The aim of this study was to determine clinical and echocardiographic characteristics, mechanisms of failure, and outcomes of mitral valve (MV) surgery after transcatheter edge-to-edge repair (TEER). Background Although >100,000 mitral TEER procedures have been performed worldwide, longitudinal data on MV surgery after TEER are lacking. Methods Data from the multicenter, international CUTTING-EDGE registry were retrospectively analyzed. Clinical and echocardiographic outcomes were evaluated. Median follow-up duration was 9.0 months (interquartile range [IQR]: 1.2-25.7 months) after MV surgery, and follow-up was 96.1% complete at 30 days and 81.1% complete at 1 year. Results From July 2009 to July 2020, 332 patients across 34 centers underwent MV surgery after TEER. The mean age was 73.8 ± 10.1 years, median Society of Thoracic Surgeons risk for MV repair at initial TEER was 4.0 (IQR: 2.3-7.3), and primary/mixed and secondary mitral regurgitation were present in 59.0% and 38.5%, respectively. The median interval from TEER to surgery was 3.5 months (IQR: 0.5-11.9 months), with overall median Society of Thoracic Surgeons risk of 4.8% for MV replacement (IQR: 2.8%-8.4%). The primary indication for surgery was recurrent mitral regurgitation (33.5%), and MV replacement and concomitant tricuspid surgery were performed in 92.5% and 42.2% of patients, respectively. The 30-day and 1-year mortality rates were 16.6% and 31.3%, respectively. On Kaplan-Meier analysis, the actuarial estimates of mortality were 24.1% at 1 year and 31.7% at 3 years after MV surgery. Conclusions In this first report of the CUTTING-EDGE registry, the mortality and morbidity risks of MV surgery after TEER were not negligible, and only

During descent, a single-winged maple seed (samara) can naturally reach a delicate equilibrium state, stable autorotation, before landing. This article reveals the intrinsic equilibrium of a particular type of samaras in terms of measurable aerodynamic and geometric parameters. To this end, we conducted a series of in situ measurements for the rate of vertical descent (exclusive of crosswind) of an autorotating samara in a natural range of samara sizes and masses. We then extended the range of size and mass by introducing artificial samaras, with discrete mass elements purposely designed to approximate the asymmetrical and nonuniform distribution of mass found with natural samaras. Based on the widened range, a fundamental nondimensional correlation of dynamic pressure and disc loading was generalized, where all stable autorotation descent profiles collapse to a single descent characteristic curve, irrespective of the size and mass of the natural and artificial samara's specimens. Results reveal that for stably autorotating (both natural and artificial) samaras, their terminal descent velocity (expressed as dynamic pressure) and disc loading attained equilibrium at a value that is inversely proportional to the coefficient of lift.

INTRODUCTION: Pharmacotherapy is a useful adjunct when patients with obesity are unable to achieve adequate benefit from lifestyle interventions. AREAS COVERED: This review covers the history of antiobesity drugs, efficacy and risks of currently approved drugs, limits of their usefulness in clinical practice, gaps in knowledge, methodological limitations of clinical trials, and reasons for underutilization. EXPERT OPINION: In randomized controlled trials, currently approved antiobesity drugs have yielded an average weight loss ranging from approximately 3% to 9% relative to placebo at 1 year. Inadequate inclusion of racial and ethnic minorities and men, and high dropout rates in clinical trials limit generalizability of these findings to clinical practice. Weight loss achieved with antiobesity drugs is generally associated with lowered glycemia, but improvements in blood pressure and lipid measures tend to be marginal. There is limited evidence for sustained weight loss beyond 1 year and for safety and efficacy of antiobesity drugs in children and adolescents, and in post-bariatric surgery patients. None have demonstrated reduction in major adverse cardiovascular events or other significant disease outcomes. Limited health insurance coverage and negative perceptions of physicians have hindered the utilization of antiobesity drugs.

We sought to determine outcomes of aortic valve replacement (AVR) versus root replacement after transcatheter AVR (TAVR) explantation because they remain unknown.From November 2009 to September 2020, data from the EXPLANT-TAVR International Registry of patients who underwent TAVR explant were retrospectively reviewed, divided by AVR versus root replacement. After excluding explants performed during the same admission as the initial TAVR and concomitant procedures involving the other valves, 168 AVR cases were compared with 28 root replacements, and outcomes were reported at 30 days and 1 year.Among 196 patients (mean age, 73.5 ± 9.9 years) who had primary aortic valve intervention at TAVR explant, the median time from TAVR to surgical explant was 11.2 months (interquartile range, 4.4-32.9 months). Indications for explant were similar between the 2 groups. Compared with AVR, patients requiring root replacement had fewer comorbidities but more unfavorable anatomy for redo TAVR (52.6% vs 26.4%; P = .032), fewer urgent/emergency cases (32.1% vs 58.3%; P = .013), longer median interval from index TAVR to TAVR explant (17.6 vs 9.9 months; P = .047), and more concomitant ascending aortic replacement (58.8% vs 14.0%; P .001). Median follow-up was 6.9 months (interquartile range, 1.4-21.6 months) after TAVR explant and 97.4% complete. Overall survival at follow-up was 81.2% with no differences between groups (log rank P = .54). In-hospital, 30-day, and 1-year mortality rates and stroke rates were not different between the 2 groups.In the EXPLANT-TAVR Registry, AVR and root replacement groups had different clinical characteristics, but no differences in short-term mortality and morbidities. Further investigations are necessary to identify patients at risk of root replacement in TAVR explant.

A single-winged maple seed (samara) is dispersed laterally by a crosswind in contrast to simply descending straight down (zero dispersion) in quiescent air. This article presents the general kinematic response of a particular type of samaras ( Acer buergerianum) in stable autorotation to the disturbance of a concentrated crosswind (simulated via slot jet) with the crosswind strength varied distinctively from weak to strong. A relatively weak crosswind slower than the tip velocity of the stably autorotating samara causes only damped undulations of its descent trajectory. In contrast, we demonstrate that the samara exhibits a bi-modal response when disturbed by a relatively strong crosswind (velocity greater than samara tip velocity). The strong crosswind enables the samara either to float laterally with the crosswind or drop-out through the crosswind with the switching of its rotational direction. Regardless of crosswind strength, stable autorotation is re-established after the samara leaves the crosswind zone, albeit accompanied by large-scale undulations in its descent trajectory. More importantly, before landing, the samara regains its original terminal descent velocity achieved in quiescent air.

Background Around 40% of school leavers in the UK attend university and individual universities generally host thousands of students each academic year. Bringing together these student communities during the COVID-19 pandemic may require strong interventions to control transmission. Prior modelling analysis of SARS-CoV-2 transmission within universities that use compartmental modelling approaches suggest that outbreaks are almost inevitable. Methods We constructed a network-based model to capture the interactions of a student population in different settings (housing, social and study). For a single academic term of a representative campus-based university, we ran a susceptible-latent-infectious-recovered type epidemic process, parameterised according to available estimates for SARS-CoV-2. We investigated the impact of: adherence to (or effectiveness of) isolation and test and trace measures; single-room isolation of cases; supplementary mass testing. Results Incorporating uncertainty in the asymptomatic fraction of cases and their associated infectivity, in the absence of interventions our model estimated that 69% (55% - 75%) of the student population could be infected during the autumn term. With full adherence to test, trace and isolate measures, we found lower cumulative infection estimates of 19% (5% - 39%). Irrespective of the adherence to isolation measures, on average a higher proportion of students resident on-campus became infected than off-campus. Room isolation generated minimal benefits. A one-off instance of mass testing would not drastically reduce the term-long case load, though if performed a couple of weeks before the end-of-term it could reduce the expected end-of-term prevalence. Regular testing, together with high adherence to isolation, test and trace measures, could reduce the proportion infected during the term by more than 50% compared to having no mass testing. Conclusions Our findings suggest SARS-CoV-2 may readily transmit in a university setting if there is limited adherence to nonpharmaceutical interventions and/or there are delays in receiving test results. Following isolation guidance and effective contact tracing curbed transmission and reduced the expected time an adhering student would spend in isolation. Additionally, widespread adherence throughout the term suppresses the amount of unwitting asymptomatic transmission to family and community members in the students’ domicile regions after term ends.

Incremental reform is an option put forward to bridge the gap between the advances made by the Affordable Care Act and Medicare for All. Starting with the premise that the barriers to enactment of Medicare for All are less than they appear, this article discusses some specific concerns about Medicare for All and how a well-implemented plan can overcome them. Regarding the bills in Congress as blueprints on which to build a foundation for a well-implemented plan, concerns about utilization, costs, funding, workforce changes, and political objections are all found to be manageable.

Spinal cord injury is a devastating condition interrupting voluntary movement and motor control. In response to unloading, skeletal muscle undergoes numerous adaptations, including rapid and profound atrophy, intramuscular fat accumulation, impaired muscular glucose metabolism and decreased force generation and muscle performance. Functional electrical stimulation (FES) involves electrically stimulating affected muscles to contract in a coordinated manner to create a functional movement or task. Effects of FES-cycling, rowing and resistance training on muscle health are described here. Briefly, FES-cycling and resistance training may slow muscle atrophy or facilitate muscle hypertrophy, and all modalities benefit muscle composition and performance to some extent. These interventions show promise as future rehabilitative tools after spinal cord injury.

This study presents, for the first time, distributions of local internal temperature and convective heat transfer in a rotating radial vane brake disk and explains mechanisms in conjunction with secondary flows and flow separation within its ventilated coolant passages. In particular, variations of radial, circumferential (vane-to-vane), and axial (inboard-to-outboard) heat transfer on internal end-wall surfaces, and their alteration due to varying number of radial vanes and rotating speed are experimentally detailed. It has been demonstrated that conventional ventilated radial brake disks where the air inflow is drawn from the inboard face are likely to suffer substantial axial variations of temperature and heat transfer between the inboard and outboard disks, which possibly exacerbates thermal distortion (i.e., coning). Further, for a typical number of vanes (i.e., 36 vanes) used on automobiles, internal thermal distributions are highly nonuniform. However, the thermal end-wall uniformity improves considerably as the number of vanes is increased to say 72 vanes. Specifically, as the number of vanes is increased, secondary flow mixing enhances overall convective heat transfer and improves thermal uniformity. In contrast, separation causes large end-wall thermal nonuniformities in radial and circumferential distributions between the pressure side and the suction side of radial vanes. This effect nonetheless also decreases as the number of vanes is increased.

Background In the UK, cases of COVID-19 have been declining since mid-April and there is good evidence to suggest that the effective reproduction number has dropped below 1, leading to a multiphase relaxation plan for the country to emerge from lockdown. As part of this staggered process, primary schools are scheduled to partially reopen on 1st June. Evidence from a range of sources suggests that children are, in general, only mildly affected by the disease and have low mortality rates, though there is less certainty regarding children’s role in transmission. Therefore, there is wide discussion on the impact of reopening schools. Methods We compare eight strategies for reopening primary and secondary schools in England from 1st June, focusing on the return of particular year groups and the associated epidemic consequences. This is assessed through model simulation, modifying a previously developed dynamic transmission model for SARS-CoV-2. We quantify how the process of reopening schools affected contact patterns and anticipated secondary infections, the relative change in R according to the extent of school reopening, and determine the public health impact via estimated change in clinical cases and its sensitivity to decreases in adherence post strict lockdown. Findings Whilst reopening schools, in any form, results in more mixing between children, an increase in R and hence transmission of the disease, the magnitude of that increase can be low dependent upon the age-groups that return to school and the behaviour of the remaining population. We predict that reopening schools in a way that allows half class sizes or that is focused on younger children is unlikely to push R above one, although there is noticeable variation between the regions of the country. Given that older children have a greater number of social contacts and hence a greater potential for transmission, our findings suggest reopening secondary schools results in larger increases in case burden than only reopening primary schools; reopening both generates the largest increase and could push R above one in some regions. The impact of less social-distancing in the rest of the population, generally has far larger effects than reopening schools and exacerbates the impacts of reopening. Discussion Our work indicates that any reopening of schools will result in increased mixing and infection amongst children and the wider population, although the opening of schools alone is unlikely to push the value of R above one. However, impacts of other recent relaxations of lockdown measures are yet to be quantified, suggesting some regions may be closer to the critical threshold that would lead to a growth in cases. Given the uncertainties, in part due to limited data on COVID-19 in children, school reopening should be carefully monitored. Ultimately, the decision about reopening classrooms is a difficult trade-off between increased epidemiological consequences and the emotional, educational and developmental needs of children.

BackgroundEven with good progress on vaccination, SARS-CoV-2 infections in the UK may continue to impose a high burden of disease and therefore pose substantial challenges for health policy decision makers. Stringent government-mandated physical distancing measures (lockdown) have been demonstrated to be epidemiologically effective, but can have both positive and negative economic consequences. The duration and frequency of any intervention policy could, in theory, could be optimised to maximise economic benefits while achieving substantial reductions in disease.MethodsHere we use a pre-existing SARS-CoV-2 transmission model to assess the health and economic implications of different strengths of control through time in order to identify optimal approaches to non-pharmaceutical intervention stringency in the UK, considering the role of vaccination in reducing the need for future physical distancing measures. The model is calibrated to the COVID-19 epidemic in England and we carry out retrospective analysis of the optimal timing of precautionary breaks in 2020 and the optimal relaxation policy from the January 2021 lockdown, considering the willingness to pay for health improvement.ResultsWe find that the precise timing and intensity of interventions is highly dependent upon the objective of control. As intervention measures are relaxed, we predict a resurgence in cases, but the optimal intervention policy can be established dependent upon the willingness to pay (WTP) per QALY loss avoided. Our results show that establishing an optimal level of control can result in a reduction in net monetary loss of billions of pounds, dependent upon the precise WTP value.ConclusionsIt is vital, as the UK emerges from lockdown, but continues to face an on-going pandemic, to accurately establish the overall health and economic costs when making policy decisions. We demonstrate how some of these can be quantified, employing mechanistic infectious disease transmission models to establish optimal levels of control for the ongoing COVID-19 pandemic.

Background The introduction of SARS-CoV-2, the virus that causes COVID-19 infection, in the UK in early 2020, resulted in the introduction of several control policies to reduce disease spread. As part of these restrictions, schools were closed to all pupils in March (except for vulnerable and key worker children), before re-opening to certain year groups in June. Finally, all school children returned to the classroom in September. Methods Here, we analyse data on school absences in late 2020 as a result of COVID-19 infection and how that varied through time as other measures in the community were introduced. We utilise data from the Department for Education Educational Settings database and examine how pupil and teacher absences change in both primary and secondary schools. Results Our results show that absences as a result of COVID-19 infection rose steadily following the re-opening of schools in September. Cases in teachers declined during the November lockdown, particularly in regions previously in tier 3, the highest level of control at the time. Cases in secondary school pupils increased for the first 2 weeks of the November lockdown, before decreasing. Since the introduction of the tier system, the number of absences with confirmed infection in primary schools was observed to be (markedly) lower than that in secondary schools. In December, we observed a large rise in the number of absences per school in secondary school settings in the South East and London, but such rises were not observed in other regions or in primary school settings. We conjecture that the increased transmissibility of the new variant in these regions may have contributed to this rise in secondary school cases. Finally, we observe a positive correlation between cases in the community and cases in schools in most regions, with weak evidence suggesting that cases in schools lag behind cases in the surrounding community. Conclusions We conclude that there is no significant evidence to suggest that schools are playing a substantial role in driving spread in the community and that careful monitoring may be required as schools re-open to determine the effect associated with open schools upon community incidence.

The introduction of SARS-CoV-2, the virus that causes COVID-19 infection, in the UK in early 2020, resulted in the UK government introducing several control policies in order to reduce the spread of disease. As part of these restrictions, schools were closed to all pupils in March (except for vulnerable and key worker children), before re-opening to certain year groups in June. Finally all school children returned to the classroom in September. In this paper, we analyse the data on school absences from September 2020 to December 2020 as a result of COVID-19 infection and how that varied through time as other measures in the community were introduced. We utilise data from the Educational Settings database compiled by the Department for Education and examine how pupil and teacher absences change in both primary and secondary schools.Our results show that absences as a result of COVID-19 infection rose steadily following the re-opening of schools in September. Cases in teachers were seen to decline during the November lockdown, particularly in those regions that had previously been in tier 3, the highest level of control at the time. Cases in secondary school pupils increased for the first two weeks of the November lockdown, before decreasing. Since the introduction of the tier system, the number of absences owing to confirmed infection in primary schools was observed to be significantly lower than in secondary schools across all regions and tiers.In December, we observed a large rise in the number of absences per school in secondary school settings in the South East and Greater London, but such rises were not observed in other regions or in primary school settings. We conjecture that the increased transmissibility of the new variant in these regions may have contributed to this rise in cases in secondary schools. Finally, we observe a positive correlation between cases in the community and cases in schools in most regions, with weak evidence suggesting that cases in schools lag behind cases in the surrounding community. We conclude that there is not significant evidence to suggest that schools are playing a significant role in driving spread in the community and that careful monitoring may be required as schools re-open to determine the effect associated with open schools upon community incidence.

Background: Operative mortality for type A aortic dissection is still 10–20% at centers of excellence. Additionally, 10–20% are not considered as viable candidates for open surgical repair and not offered life-saving emergency surgery. ARISE is a multicenter investigation evaluating the novel GORE® Ascending Stent Graft (ASG; Flagstaff, AZ). Objective: The purpose of this study is to assess early feasibility of using these investigational devices to treat ascending aortic dissection. Methods: This a prospective, multicenter, non-randomized, single-arm study that enrolls patients at high surgical risk with appropriate anatomical requirements based on computed tomography imaging at 7 of 9 US sites. Devices are delivered transfemorally under fluoroscopic guidance. Primary endpoint is all-cause mortality at 30 days. Secondary endpoints include major adverse cardiovascular and cerebrovascular events (MACCE) at 30 days, 6 months, and 12 months. Results: Nineteen patients were enrolled with a mean age of 75.7 years (range 47–91) and 11 (57.9%) were female. Ten (52.6%) had DeBakey type I disease, and the rest were type II. Sixteen (84.2%) of the patients were acute. Patients were treated with safe access, (7/19 (36.8%) percutaneous, 10/19 (52.6%) transfemoral, 2/19 (10.5%) iliac conduit), delivery, and deployment completed in all cases. Median procedure time was 154 mins (range 52–392) and median contrast used was 111 mL (range 75–200). MACCE at 30 days occurred in 5 patients including mortality 3/19 (15.8%), disabling stroke in 1/19 (5.3%), and myocardial infarction in 1/19 (5.3%). Conclusion: Results from the ARISE early feasibility study of a specific ascending stent graft device to treat ascending aortic dissection are promising.

Thermofluidic behaviors governing the enhanced cooling performance of the wire-woven-bulk diamond (WBD) cored brake disc in comparison with the conventional pin-finned brake disc used on heavy vehicles were characterized experimentally. For each type of brake disc, detailed internal thermofluidic data of the two rotating brake discs were obtained using transient thermochromic liquid crystal (TLC) for end-wall heat transfer and particle image velocimetry (PIV) for the inflow field. The results demonstrate that the pin-finned brake disc exhibits a circumferentially periodic curved inline-like passage flow and large dead flow regions, with strong recirculation that reduces its thermal dissipation performance. The cooling advantage of the WBD core is primarily attributed to the combination of enlarged heat transfer surface area (both end-wall and core) and greater utilization of the larger surface due to favorable fluidic behavior developed from the WBD topology. The internal WBD core has approximately three times the surface density of the pin-finned disc which, in combination with the smaller and weaker recirculation zones, leads to more effective usage of the available core surface area for thermal dissipation. The aerodynamic anisotropy of the WBD core induced by its topological anisotropy causes a globally irregular thermofluidic distribution in the brake disc.

Highlights • Adaptive epidemic control. • Using real-time outbreak information to improve epidemic control. • Active Adaptive Management in an epidemiological setting. • Analysing the interaction between control and monitoring during an epidemic., Infectious disease epidemics present a difficult task for policymakers, requiring the implementation of control strategies under significant time constraints and uncertainty. Mathematical models can be used to predict the outcome of control interventions, providing useful information to policymakers in the event of such an epidemic. However, these models suffer in the early stages of an outbreak from a lack of accurate, relevant information regarding the dynamics and spread of the disease and the efficacy of control. As such, recommendations provided by these models are often incorporated in an ad hoc fashion, as and when more reliable information becomes available. In this work, we show that such trial-and-error-type approaches to management, which do not formally take into account the resolution of uncertainty and how control actions affect this, can lead to sub-optimal management outcomes. We compare three approaches to managing a theoretical epidemic: a non-adaptive management (AM) approach that does not use real-time outbreak information to adapt control, a passive AM approach that incorporates real-time information if and when it becomes available, and an active AM approach that explicitly incorporates the future resolution of uncertainty through gathering real-time information into its initial recommendations. The structured framework of active AM encourages the specification of quantifiable objectives, models of system behaviour and possible control and monitoring actions, followed by an iterative learning and control phase that is able to employ complex control optimisations and resolve system uncertainty. The result is a management framework that is able to provide dynamic, long-term projections to help policymakers meet the objectives of management. We investigate in detail the effect of different methods of incorporating up-to-date outbreak information. We find that, even in a highly simplified system, the method of incorporating new data can lead to different results that may influence initial policy decisions, with an active AM approach to management providing better information that can lead to more desirable outcomes from an epidemic.

BackgroundShort-term forecasts of infectious disease can aid situational awareness and planning for outbreak response. Here, we report on multi-model forecasts of Covid-19 in the UK that were generated at regular intervals starting at the end of March 2020, in order to monitor expected healthcare utilisation and population impacts in real time.MethodsWe evaluated the performance of individual model forecasts generated between 24 March and 14 July 2020, using a variety of metrics including the weighted interval score as well as metrics that assess the calibration, sharpness, bias and absolute error of forecasts separately. We further combined the predictions from individual models into ensemble forecasts using a simple mean as well as a quantile regression average that aimed to maximise performance. We compared model performance to a null model of no change.ResultsIn most cases, individual models performed better than the null model, and ensembles models were well calibrated and performed comparatively to the best individual models. The quantile regression average did not noticeably outperform the mean ensemble.ConclusionsEnsembles of multi-model forecasts can inform the policy response to the Covid-19 pandemic by assessing future resource needs and expected population impact of morbidity and mortality.

This study presents local temperature and heat transfer coefficient distributions obtained experimentally on the internal surfaces of a rotating pin-finned brake rotor at realistic rotation speeds for braking (i.e., N = 100–300 rpm). To this end, the thermochromic liquid crystal technique in a rotating reference frame was employed. The results demonstrate that the bulk airflow within the ventilated channel of a rotating disk follows a predominantly backward sweeping inline-like path between the pin fins. Internal local heat transfer is distributed nonuniformly on both inboard and outboard surfaces, with twice higher average cooling from the outboard surface than the inboard surface: this possibly exacerbates the thermal stresses, which leads to thermal distortion of the rotor (i.e., coning).

A short pin-fin array has been used to improve the internal cooling characteristics at the trailing edge of some gas turbine blade designs. In such a cooling scheme, the pin-fin array that is sandwiched by the turbine blade’s inner surfaces, experiences a uniform-like coolant stream. The local elevation of internal heat transfer especially on the end-walls (i.e., inner blade surfaces) at the trailing edge is achieved predominantly by horseshoe vortex-type secondary flows whose fluidic behavior has been well established. A modification to this cooling scheme has been made by introducing a blockage upstream, causing multiple jets to impinge on the pin-fins – the blockage jets. Previous studies on the internal cooling scheme employing the blockage jets have assumed that the end-wall flow topology is similar to that formed by the horseshoe vortex-type secondary flows due to similar local heat transfer distributions. However, there is no detailed and sufficient acknowledgement made of the lack of an approaching boundary layer. Therefore, the present study experimentally investigates local heat transfer around a single short pin-fin subjected to a fully turbulent jet impingement simulating the blockage jet impingement and demonstrates that the end-wall flow topology loosely resembles that formed by a horseshoe vortex system and is strictly different, depending on the distance between the jet exit and the pin-fin, relative to the length of the jet’s potential core.

We experimentally examine the impingement of a fully turbulent round jet (with diameter Dj) on a long circular cylinder (with diameter D) in the crossflow plane coinciding with the jet axis for D/Dj = 2.5 and ReDj = 20,000. Particular focus is placed on the kinematics of boundary layer transition that occurs and subsequently leads to a second thermal peak on the cylinder surface downstream of the primary thermal peak near the stagnation point when placed inside the jet’s potential core. To this end, spectral analyses of wall shear stress data and time-resolved velocity data within both laminar and turbulent boundary layers have been performed. The present study demonstrates that the root mean square (rms) fluctuation of the stream-wise velocity component increases along both boundary layers due to the propagation of external perturbations from coherent structures that are shed from the jet exit, which incites the transition of the laminar boundary layer. The transition causes the local heat transfer elevation that interrupts the monotonic decrease from the primary thermal peak whereas it plays no direct part in forming the second thermal peak. Instead, the second thermal peak occurs at a delayed downstream azimuth angle from the transition where the rms velocity fluctuations of the boundary layer flow reach their peak at the dominant frequency, equivalent to that of the coherent structures of the jet.

The steady, isothermal-fluidic field of forced moderator streams in a ¼ scaled moderator circulation tank (MCT) of a CANDU-6 reactor is analysed. Particular focus is placed on characterizing a secondary jet formed by the collision of symmetric, counter flowing wall jets discharged upwards by nozzles installed at each side of the MCT’s horizontal axis. Two separate sets of experiments have been conducted employing water and air as the working fluids with different nozzle configurations (i.e., discrete dove-tail nozzles for water and two-dimensional slot jet nozzles for air). Then, cross validation of the fluidic data sets from these two different test facilities have been made where the fluidic similarity of the secondary jet generated by the inlet nozzles (particularly its rate of dissipation as it interacts with the calandria tubes (CTs)) has been established. Based on the established fluidic similarity, a series of numerical simulations have been performed according to the boundary conditions obtained extensively from the two-dimensional MCT experiments. Subsequently, the numerical results have been validated against the experimental data to assess the capability of a commercial code (ANSYS CFX V15.0) to resolve the moderator interaction with the CTs. It has been demonstrated that a monotonic decay of the secondary jet whose peak (having roughly 50% of the nozzle’s exit mean vertical velocity component) exists at the throat of the first row of the calandria tubes in the MCT takes place. After which, the momentum of the secondary jet is substantially reduced along its centreline. The rate of dissipation of the secondary jet is under-predicted by the default k-ω SST turbulence model, leading to a dramatic over-prediction of the penetration distance of the secondary jet into the core region. However, the accuracy of the numerical results can be substantially improved with turbulence model parameter tuning to achieve a closer fit with the reference experimental data.

International audience; Our aim in CASP12 was to improve our Template‐Based Modeling (TBM) methods through better model selection, accuracy self‐estimate (ASE) scores and refinement. To meet this aim, we developed two new automated methods, which we used to score, rank, and improve upon the provided server models. Firstly, the ModFOLD6_rank method, for improved global Quality Assessment (QA), model ranking and the detection of local errors. Secondly, the ReFOLD method for fixing errors through iterative QA guided refinement. For our automated predictions we developed the IntFOLD4‐TS protocol, which integrates the ModFOLD6_rank method for scoring the multiple‐template models that were generated using a number of alternative sequence‐structure alignments. Overall, our selection of top models and ASE scores using ModFOLD6_rank was an improvement on our previous approaches. In addition, it was worthwhile attempting to repair the detected errors in the top selected models using ReFOLD, which gave us an overall gain in performance. According to the assessors' formula, the IntFOLD4 server ranked 3rd/5th (average Z‐score > 0.0/–2.0) on the server only targets, and our manual predictions (McGuffin group) ranked 1st/2nd (average Z‐score > −2.0/0.0) compared to all other groups.