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Breaking the cycle: why women of reproductive age belong in all areas of health research
No full textFluid resuscitation in pediatric cerebral malaria: insights from the FEAST trial and further evidence from Malawi
No full textPorosity-limited transport during two-phase surfactant/polymer floods in a layered sandstone
No full textSurfactant/polymer flooding presents itself as an attractive technique for the full utilization of current reservoirs given its potential to yield high oil recoveries. Despite this appeal, discrepancies between laboratory and field results exist and limit their industrial implementation. Within the scale-up process, corefloods serve as a key tool for the evaluation of the recovery potential; however, due to complexities in the fluid system itself, these are commonly performed on homogeneous core samples. To further understand this, we conduct a surfactant/polymer flood as a tertiary recovery method within a Nugget sandstone core. A notable feature of the chosen core is its stratified nature, with layers of high and low porosity characterized via X-ray CT. Via the use of direct imaging, coupled with a step tracer test, preferential flow paths and slow-to-ingress regions of the core are identified, information that is then coupled with the surfactant/polymer flood results to better understand the mechanisms at play. To better understand the influence of the structured heterogeneity present within the core, the results are compared to an analogous experiment within a homogeneous sandstone core. We note the inability of an oil bank to form and the comparatively larger variability of the recoveries between different porosity layers within the core. Lastly, we highlight how, despite a high overall recovery of 80%, inefficiencies in the displacement process are still present and only observable due to the direct imaging methodology implemented, ultimately showcasing its value in this context
Exploratory simulations on the effectiveness of sand protection strategies against firebrand accumulation in wildfires
No full textFirebrands are the leading cause of infrastructure damage during wildfires. However, dedicated protections specifically designed to mitigate firebrand accumulation, remain limited. In contrast, infrastructure protection strategies against sand accumulation have been developed, implemented and studied in detail. Because both sand and firebrands are airborne particles, this paper explores the potential applicability of sand protection strategies to mitigate firebrand exposure. A literature review of existing protection strategies from both sand and firebrands is presented, followed by exploratory numerical simulations using Fire Dynamics Simulator (FDS). The simulations study the effectiveness of shielding a simplified cubic structure from particles simulating firebrand exposure under varying ambient wind speeds (4, 6, and 8 m/s). Two sand protection strategies are simulated, a trench and wall protection; results indicate the selected protections have the potential to reduce firebrand exposure to a target obstacle. The findings provide novel insights into the feasibility of translating sand protection strategies to firebrand mitigation and establish a foundation for innovative infrastructure solutions against wildfires
Long-term colorectal cancer incidence in a post-endoscopic screening cohort, accounting for surveillance, by baseline polyp group, anatomic subsite, and sex
No full textObjectives:
Colonoscopy surveillance is often performed in post-polypectomy cohorts, likely altering colorectal cancer (CRC) outcomes, but this is often not addressed in CRC incidence analyses. We examined CRC incidence post-endoscopic screening, accounting for surveillance.
Methods:
We examined UK Flexible Sigmoidoscopy Screening Trial participants who had no, low-risk, or high-risk (≥10 mm, ≥3 adenomas, adenomas with villous features/high-grade dysplasia) distal polyps at screening. Participants with high-risk polyps had an index colonoscopy and 81% had ≥1 surveillance colonoscopies post-screening; <1% of those with no/low-risk polyps had an index or surveillance colonoscopy. We examined CRC incidence over 21 years by anatomic subsite and sex. Standardised incidence ratios (SIRs) compared incidence to general population incidence.
Results:
Of 39,417 participants, 29,792 (76%), 8162 (21%), and 1463 (4%) had no, low-risk, and high-risk polyps, respectively. In the high-risk group, all-site CRC incidence was non-significantly different from that in the general population, when including all participants, just those who attended surveillance, or just those who did not attend surveillance (SIRs: 0.81 [95% confidence interval: 0.60–1.07]; 0.75 [0.54–1.03]; 1.12 [0.56–2.01], respectively). Without surveillance, compared to the general population, distal cancer incidence was lower among women and men without polyps (SIRs: 0.30 [0.24–0.37]; 0.24 [0.20–0.29], respectively) and women and men with low-risk polyps (SIRs: 0.52 [0.34–0.76]; 0.27 [0.19–0.37], respectively); proximal cancer incidence was lower among men without polyps (SIR: 0.75 [0.64–0.88]), non-significantly different among women without polyps (SIR: 1.07 [0.93–1.22]) and men with low-risk polyps (SIR: 1.22 [0.98–1.51]), but higher among women with low-risk polyps (SIR: 2.22 [1.77–2.76]).
Conclusions:
Women with low-risk distal polyps at flexible sigmoidoscopy screening had double the risk of proximal colon cancer, compared to the general population
Position-feedback integral IDA-PBC for constant matched and unmatched disturbances
No full textThis work investigates the passivity-based control of a class of underactuated mechanical systems subject to constant matched and unmatched disturbances, for which the momenta are not measured. The main contribution is a new design of the integral interconnection-and-damping assignment passivity-based control that only relies on position feedback. Numerical simulations on a disk-on-disk system, on an Acrobot system, and on a rigid-link model representative of a soft continuum manipulator demonstrate the effectiveness of the new controller
Risk-aware stochastic vehicle trajectory prediction with spatial-temporal interaction
No full textAutonomous vehicles need to continuously analyse the driving context and establish a comprehensive understanding of the dynamic traffic environment. To ensure the safety and efficiency of their operations, it would be beneficial to have accurate predictions of surrounding vehicles’ future trajectories. AVs can adjust their motions proactively to improve road safety and comfort with such information. This paper proposes a novel approach to predict the future trajectories of interacting vehicles, through a model of potential spatial-temporal interactions. A unique kernel function that emphasises risk-awareness was developed to extract spatial dependencies. The established model was trained and evaluated with the publicly available Highway Drone Dataset and Intersection Drone Dataset. The performance of the developed model was assessed with eight state-of-the-art methods. An ablation study and safety analysis were also conducted to evaluate the proposed risk-awareness kernel function. Results show that the proposed model’s inference speed is over eight times faster than the commonly used LSTM-based models. It also achieves an improvement of over 8% in prediction accuracy when compared with the state-of-the-art model
Role of aortic root motion in fluid-structure interaction simulations of ascending thoracic aortic aneurysm
No full textObjective: Computational modelling of ascending thoracic aortic aneurysms (ATAA) typically assumes zerodisplacement at the model's inlet. In this study we incorporated different types of aortic root motion into fluid-structure interaction (FSI) models representing an ATAA and a healthy aorta to examine their impacts on wall stress and wall shear stress (WSS) predictions. Methods: Five types of boundary conditions were specified at the inlet of the solid domain: (a) zerodisplacement constraints, (b) longitudinal displacement, (c) inplane displacement, (d) combined longitudinal and in-plane displacement, and (e) rotation. The aortic walls were prestressed and modelled as anisotropic hyperelastic materials. A transitional turbulence model was employed to simulate the non-Newtonian blood flow, together with patient-specific boundary conditions. Results: Combined longitudinal and in-plane displacement at the aortic root increased regions with elevated maximum principal stress (MPS > 250 kPa) by 331% for the healthy aorta, and 57.1% for the ATAA model. Peak wall stress showed modest increases by 11.4% and 14% in the ATAA model and healthy aorta, respectively. Combined longitudinal and in-plane displacement increased the area of extremely high WSS regions (> 20 Pa) by 20.5% in the ATAA model, primarily in the ascending aorta. For the healthy aorta, rotation had the most notable impact on WSS, reducing the area of elevated WSS regions (> 7 Pa) by 18.8%. Conclusion: Our results highlight the importance of incorporating aortic root motion into FSI models for more accurate prediction of aortic wall stress and WSS. This would enhance patient-specific risk stratification for patients with ATAA
Receptor clustering tunes and sharpens the selectivity of multivalent binding
No full textThe immune system exploits a wide range of strategies to combine sensitivity with selectivity for optimal response. We propose a generic physical mechanism that allows tuning the location and steepness of the response threshold of cellular processes activated by multivalent binding. The mechanism is based on the possibility to modulate the attraction between membrane receptors. We use theory and simulations to show how tuning interreceptor attraction can enhance or suppress the binding of multivalent ligand-coated particles to surfaces. The changes in the interreceptor attraction less than the thermal energy kBT can selectively switch the receptor-clustering and activation on or off in an almost step-wise fashion, which we explain by near-critical receptor density fluctuations. We also show that the same mechanism can efficiently regulate the onset of endocytosis for, e.g., drug delivery vehicles
Innovative interventions for transforming road capacity, safety and emissions on the England's strategic road network
No full textTraffic demand has been forecasted to increase between 24 % to 72 % by 2040 on the England's Strategic Road Network (SRN), exacerbating existing problems relating to collisions, congestion and climate change. This paper aims to identify and investigate innovative interventions to tackle the challenges of improving road capacity, safety and reducing emissions so as to enhance the SRN's performance without constructing new roads. The interventions are categorised in four well-established themes: (i) behaviour and policy, which includes measures such as promoting active travel and public transport usage; (ii) infrastructure, focusing on optimising road and junction design; (iii) connectivity and automation, such as dynamic lane management; and (iv) sustainability, encompassing both harnessing renewable energy sources within the road network and the reduction of emissions from corporate and road users. A thorough review of academic literature and the analysis of documents published by governments and industry worldwide were undertaken to identify key interventions and assess their potential effects on improving road capacity, safety and emissions reduction, particularly on high-speed road networks. Following the examination of these interventions, they are evaluated against a new comprehensive and holistic framework known as PESTEL denoting Policy, Economic, Safety, Technology, Environmental and Location dimensions. The selected interventions were systematically ranked using the widely adopted Analytical Hierarchy Process (AHP), ensuring a structured and objective evaluation. This holistic methodology would be valuable to network operators who intend to evaluate any intervention, going beyond a standard cost-benefit analysis by attributing a score to each component examined. Furthermore, a time-cost matrix has been established analysing the implementation cost and duration for each of the key interventions. Finally, this paper presents an implementation strategy on how such interventions could be employed within the England's Strategic Road Network