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Posterior left pericardiotomy reduces postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting surgery
No full textObjective:
Atrial fibrillation (AF) is a common postoperative complication with an incidence of up to 10% to 33% after coronary artery bypass grafting surgery and is associated with worse morbidity and mortality. At present, studies have shown a promising reduction in postoperative AF (POAF) with posterior pericardiotomy (PP). However, there are limited data on the widespread use of PP amongst cardiac surgeons. This retrospective analysis assesses the influence of a real-world adoption of PP on the incidence and cumulative burden of POAF.
Methods:
Patients who underwent coronary artery bypass grafting surgery between 2015 and 2022 were analyzed. One group had PP as part of their surgical procedure whilst the control group did not. For both groups, the incidence of POAF was analyzed. PP was performed via a 5-cm incision between the left inferior pulmonary vein and the phrenic nerve.
Results:
Two thousand four hundred eighty patients were included in the analysis; 806 patients underwent PP and 1674 formed the control group. PP was associated with a 27.4% reduction in the odds of developing POAF (odds ratio, 0.73; 95% CI, 0.55-0.95; P = .023). Age was significantly associated with POAF, with a 4.3% increase in odds per additional year (odds ratio, 1.04; 95% CI, 1.03-1.06; P < .001). In the multivariate model for AF, PP remained significantly protective, reducing the odds of POAF by 26.9% (odds ratio, 0.73; 95% CI, 0.55-0.96; P = .028). Patients who underwent PP had significantly reduced cumulative POAF duration, with a 5.3% average reduction (P = .002).
Conclusions:
Posterior left pericardiotomy is associated with reduced odds and duration of POAF. A large, multicenter trial is indicated to confirm this finding as well as the influence of PP and POAF on postdischarge clinical outcomes
Aspect ratio controls hot-carrier generation in gold nanobricks
No full textEnergetic or “hot” electrons and holes generated from the decay of localized surface plasmons in metallic nanoparticles have great potential for applications in photocatalysis, photovoltaics, and sensing. Here, we study the generation of hot carriers in brick-shaped gold nanoparticles using a recently developed modeling approach that combines a solution to Maxwell’s equation with large-scale tight-binding simulations to evaluate Fermi’s Golden Rule. We find that hot-carrier generation depends sensitively on the aspect ratio of the nanobricks with flatter bricks, producing a large number of energetic electrons irrespective of the light polarization. In contrast, the hot-carrier generation rates of elongated nanobricks exhibit a strong dependence on the light polarization. The insights resulting from our calculations can be harnessed to design nanobricks that produce hot carriers with properties tailored to specific device applications
Simulation and behaviour of single-span portal frames, Part II: parametric analysis and practical implications
No full textThe finite element (FE) model developed and validated in the companion paper is employed herein to systematically study the influence of key parameters, including span, height and length, on the structural behaviour of single-span portal frames under serviceability levels of vertical, wind sway, wind uplift and thermal loading. The effects of stressed skin action, as influenced by these parameters, on the overall frame behaviour are also investigated. Additionally, a new parameter, the shear angle, is proposed to facilitate the identification of critical locations and trends for screw forces within the secondary steelwork and cladding system. The main findings are that (1) among the loading cases considered, wind sway loading is the most critical in terms of screw forces, with screw displacements exceeding 20 mm and 7 mm on the gable and roof cladding, respectively, in the largest models, while thermal loading is less detrimental, (2) the gable frame experiences up to four times higher reaction forces than expected, especially under wind sway loading, and this increases with increasing stiffness of the gable frame relative to the internal frames, (3) the side lap stitching screws are the critical (most heavily loaded) connectors and the proposed shear angle is able to effectively identify the critical areas and the trends in screw forces, and (4) introducing bracing reduces the shear forces resisted by the screws and cladding. Furthermore, practical suggestions for mitigating the risk of screw failure are discussed
Safety and immunogenicity of investigational tuberculosis vaccine M72/AS01E–4 in people living with HIV in South Africa: an observer-blinded, randomised, controlled, phase 2 trial
No full textBackground
M72/AS01E–4 is a recombinant fusion protein vaccine candidate derived from two Mycobacterium tuberculosis antigens (Mtb32A and Mtb39A) and AS01E–4 adjuvant. We evaluated safety and immunogenicity of M72/AS01E–4 in people living with HIV in South Africa.
Methods
In this observer-blinded, randomised, controlled, phase 2 trial, participants aged 16–35 years with well controlled HIV were enrolled from urban, semi-urban, and semi-rural settings in South Africa, including sites with high tuberculosis and HIV prevalence, as well as agricultural and mining communities. Participants were randomly assigned (1:1), stratified by site and interferon-gamma release assay (IGRA) status, to receive two intramuscular doses of M72/AS01E–4 or placebo. Eligibility criteria included antiretroviral therapy for at least 3 months, HIV viral load of less than 200 copies per mL, CD4 counts of 200 cells per μL or higher, and previous completion of tuberculosis preventive therapy and no tuberculosis history. The sponsor and its delegates, the laboratory team, investigators, site staff, and participants were blinded to randomisation, whereas an unblinded pharmacist who was not involved in trial procedures prepared placebo and reconstituted M72/AS01E-4 in unit-dose syringes covered with a blinding label. All participants who received at least one dose of either M72/AS01E–4 or placebo were included in the safety population for safety analyses. Immunogenicity analyses were conducted using the per-protocol population, which included participants who received the intervention as planned and did not substantially deviate from the protocol procedures. Safety assessments included solicited adverse events in the first 7 days after each dose, unsolicited adverse events in the first 28 days after each dose, and serious adverse events. Humoral responses were measured with ELISA and cellular responses were assessed using multiparameter flow cytometry, in the per-protocol population. This study is complete and is registered with ClinicalTrials.gov, NCT04556981.
Findings
Between Nov 17, 2020, and Aug 12, 2022, 402 eligible participants were assigned treatment, of whom 401 participants received at least one dose of M72/AS01E–4 (n=201; 175 [87%] were female and 26 [13%] were male; 196 [98%] were Black) or placebo (n=200; [176 [88%] were female and 24 [12%] were male; 196 [98%] were Black) and followed for a median duration of 372 days (IQR 364–389). Among M72/AS01E–4 recipients, solicited adverse events were more frequent, ranging from 17% (33 of 199) for gastrointestinal symptoms to 77% (140 of 183) for injection-site pain. Most events were mild to moderate, with severe events ranging from 0% (0 of 197) for swelling and (0 of 198) redness to 13% (24 of 183) for injection-site pain, resolving within 3 days. Unsolicited adverse events related to vaccine were mainly injection-site reactions in the M72/AS01E–4 group (8% [15 of 201] vs 1% [two of 200] in the placebo group), including erythema, pruritis, swelling, bruising, induration, and pain. No vaccine-related serious adverse events were reported. Among M72/AS01E–4 recipients at day 57 (1 month after dose two), M72-specific antibody geometric mean concentration (GMC) was 479·70 EU/mL (95% CI 421·79–545·56) with median magnitude of CD4 cells of 0·383% (IQR 0·177%–0·663). Among M72/AS01E–4 recipients, at day 57 GMCs were 559·49 EU/mL (95% CI 461·75–677·93) in with baseline IGRA positivity and 424·95 EU/mL (357·74–504·80) in those without; median magnitudes of CD4 cells were 0·447% (IQR 0·287–0·819) and 0·321% (0·147–0·581).
Interpretation
The two-dose regimen of the M72/AS01E–4 tuberculosis vaccine was immunogenic, with an acceptable safety profile. These outcomes led to the inclusion of people living with HIV in the ongoing global registration phase 3 trial
Asymptotic analysis of the 2D narrow-capture problem for partially accessible targets
No full textIn this paper we use singular perturbation theory to solve the 2D narrow capture problem for a set of partially accessible targets U, =1,…,, in a bounded domain Ω⊂ℝ2. In contrast to previous models of narrow capture, we assume that when a searcher finds a target by attaching to the partially adsorbing surface U it does not have immediate access to the resources within the target interior. Instead, the searcher remains attached to the surface for a random waiting time , after which it either gains access to the resources within (surface absorption) or detaches and continues its search process (surface desorption). We also consider two distinct desorption scenarios – either the particle continues its search from the point of desorption or rapidly returns to its initial search position. In applications to animal foraging, the latter would correspond to an animal returning to its home base whereas the resources within a target could represent food or shelter. We formulate the narrow capture problem in terms of a set of renewal equations that relate the probability density and target flux densities for absorption to the corresponding quantities for irreversible adsorption. The renewal equations, which effectively sew together successive rounds of adsorption and desorption prior to the final absorption event, provide a general probabilistic framework for incorporating non-Markovian models of desorption/absorption and different search scenarios following desorption. We solve the general renewal equations in two stages. First, we calculate the Laplace transformed target fluxes for irreversible adsorption by solving a Robin boundary value problem (BVP) in the small-target limit using matched asymptotic analysis. We then use the inner solution of the BVP to solve the corresponding Laplace transformed renewal equations for non-Markovian desorption/absorption, which leads to explicit Neumann series expansions of the corresponding target fluxes. Finally, the latter are used to determine the corresponding splitting probabilities and conditional mean FPTs for absorption
Iterative Stackelberg equilibrium finding for linear quadratic differential games
No full textWe propose two iterative methods to determine a linear feedback Stackelberg equilibrium solution in two-player linear quadratic differential games between a leader and a follower. The update laws involve the solution of Lyapunov or Riccati equations. Conditions for recursive feasibility and local convergence of the update laws are analysed and illustrated via numerical examples
Representative microstructures for two-dimensional computational studies of ultrasonic wave propagation in titanium alloys
No full textMacrozones in Ti–6Al–4V are a likely cause of reduced fatigue lives of aero-engine components. Whilst past research has demonstrated great potential for ultrasonic testing to characterize macrozones via attenuation, backscatter and velocity, the fundamental physical understanding of the ultrasound-material interactions is hindered by the complexity of the microstructures and the difficulties in manufacturing and fully characterizing samples with varying degrees of macrozones. In this study, we present important developments towards generating realistic synthetic macrozone models in finite element (FE) simulations which incorporate the complete hierarchical microstructures as revealed by electron backscatter diffraction (EBSD) scans. This involves first the extraction of grain statistics from a two-dimensional EBSD micrograph, based on which representative hierarchical microstructures of both morphologies and crystallographic texture are then synthesized in two dimensions. The synthetic models are calibrated against the original statistics and validated using FE wave propagation models to study the wave behaviours, where potential causes of loss of fidelity are analysed and discussed. Our hope is that with continued development and expansion to three-dimensional, this synthetic EBSD approach, where every detail of the representative microstructures is accessible, will lay the foundation for systematic investigation of the complex wave-macrozone interactions and better detection and characterization of macrozones
An approach for including heat pump performance in the design of thermo-active piles
No full textThe focus on sustainable built environment has grown with the drive for net-zero. The use of pile foundations and other geotechnical structures as ground heat exchangers (GHEs) is key to unlocking the economic viability of ground-source energy systems (GSESs) in dense urban areas. However, current design procedures characterise the performance of GHEs under a given temperature or heat flux, which consider the heat exchanger in isolation from the rest of the GSES. This study proposes a new method to assess the thermal performance of GHEs based on the electricity consumption of the heat pump by introducing explicitly a model describing its performance based on operating temperatures. This general method is applied to a thermo-active pile, providing insights into the impact of pile diameter and length
Enhanced water management using Nafion matrix mixed membranes to improve PEM fuel cell performance by the incorporation of covalent functionalized electrochemical exfoliated graphene oxide
No full textHydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity. The incorporation of APTS (3-(aminopropyl)triethoxysilane) into exfoliated graphene oxide (EGO) by covalent functionalization to be used as filler into Nafion membranes allows higher hydrophilicity for these membranes. This is associated with promoting hydroxyl, carbonyl, siloxane, silane, and amine groups within the EGO-APTS matrix. The incorporation of these materials as Fuel Cell MEAs leads to a significant reduction of the ohmic resistance measured at high frequency resistance (HFR) in electrochemical impedance spectroscopy (EIS) experiments and achieves maximum power densities of 1.33 W cm−2 at 60 °C at 100% RH (APTS-EGO, 0.2 wt%) and 1.33 W cm−2 at 60 °C at 70% RH (APTS-EGO, 0.3 wt%), which represents an improvement of 190% compared to the commercial Nafion 212 when utilizing low humidification conditions (70%). Moreover, the as-synthesized membrane utilizes lower Nafion ionomer mass, which, in conjunction with the excellent cell performance, has the potential to decrease the cost of the membrane from 87 to 80 £/W as well as a reduction of fluorinated compounds within the membrane
The impact of green skills and green capabilities on firms’ financial performance: a systematic literature review
No full textGreen skills and capabilities in organisations are important enablers of net-zero transition as they determine firms’ ability to adopt sustainability as a core business strategy. This study conducts a systematic literature review of 84 scholarly articles and 7 industry publications to examine the conceptualisation of green skills and green capabilities in firms, their influence on firms’ financial performance, and the factors shaping these complex relationships. Findings reveal that the green skills and green capabilities concepts are broad and ambiguously defined, necessitating greater conceptual clarity, especially with respect to how the green skills and capabilities relate to each other. Accordingly, the study develops a framework outlining different green skill and capability typologies and their interconnections. Additionally, six key performance categories—(1) costs, (2) profitability, (3) efficiency and productivity, (4) firm growth, (5) liquidity, and (6) market performance— are identified inductively, with evidence from the literature indicating that both green skills and green capabilities positively impact each of these areas. Results suggest that while the overall effect of green skills and capabilities on financial performance is positive, several contextual factors, such as firm size, sector, and region, influence this relationship. The study highlights the most significant caveats and their implications, contributing to a more nuanced understanding of the knowledge–performance link for the net-zero transition