Publications

An experimental investigation into the effect of moment gradients on the flexural behaviour of hot-rolled high strength steel square hollow section (SHS) beams is presented in this paper. In total, 20 beam specimens in steel grades S690 and S770, and with cross-sections spanning from Class 2 to Class 4 based on the Eurocode 3 slenderness limits, were tested under three- and four-point bending. In the three-point bending tests, the beam spans were varied to achieve a range of moment gradients; the influence of different stiffening arrangements at the loading point was also considered. Local geometric imperfections were measured by means of 3D laser-scanning prior to testing and digital image correlation (DIC) was adopted to monitor the displacement and strain fields at critical regions and to assess the local buckling half-wavelengths of the test specimens for which a consistent measurement approach was proposed. The measured local buckling half-wavelengths were compared against the elastic local buckling half-wavelengths calculated using the finite strip method. It was observed that while the measured local buckling half-wavelengths remained approximately constant up to first yield, a significant reduction in half-wavelength was observed with increasing moment due to the non-uniform spread of plasticity. The comparisons also revealed that the local buckling half-wavelengths reduced with both the presence of moment gradients and intermediate stiffeners, with a new parameter proposed to quantify the local moment gradient. It was shown from the tests that the specimens subjected to moment gradients, despite the presence of shear, exhibited higher ultimate moment capacities (up to 10.5% for stiffened specimens and 3.4% for unstiffened specimens) than those subjected to uniform moments. This is attributed to the delay in the local buckling of the critical cross-section of beams under moment gradients due to the restraint provided by the less heavily stressed adjacent cross-sections.

The goal of the study was to compare long-term outcomes of percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG), accounting for the clinical impact of individual components in the composite endpoints and prioritising these using the win ratio (Rw).The win ratio was compared with conventional methods of analyses (hazard ratio [HR] and relative risk) in the SYNTAX trial (n=1,800). For the composite of death/stroke/myocardial infarction (MI), the win ratio favoured CABG and was 1.37 (95% CI: 1.10-1.77) for matched analysis, 1.28 (95% CI: 1.11-1.53) for unmatched analysis, while the conventional HR was 1.29 (95% CI: 1.11-1.53). The largest number of winners in favour of CABG over PCI were based on MI (n=39 vs. n=19, respectively). Death was significantly reduced with CABG in matched (Rw=1.39, 95% CI: 1.04-1.86) and unmatched win ratio analyses (Rw=1.27, 95% CI: 1.01-1.42) as compared with non-significant conventional analysis (HR 1.19, 95% CI: 0.92-1.56). In subgroups, matched win ratio analyses had a larger treatment effect in favour of CABG compared with conventional analyses, especially in patients with three-vessel disease and intermediate SYNTAX scores, while unmatched win ratios had a smaller point estimate, but with narrower confidence intervals than matched analyses findings.This re-analysis of the SYNTAX trial using the win ratio shows that the most important benefit of CABG treatment is the reduction of hard clinical endpoints such as mortality and MI. Future trials using this approach can expect to maintain similar statistical power with smaller sample sizes, and thereby reduce the cost of a trial.

No abstract is provided for this article.

Background Microvascular resistance reserve (MRR) can characterize coronary microvascular dysfunction (CMD); however, its prognostic impact in ST-segment elevation myocardial infarction (STEMI) patients remains undefined. Objectives This study sought to investigate the prevalence of CMD in STEMI patients and to elucidate the prognostic performance of MRR. Methods This prospective cohort study enrolled 210 STEMI patients with multivessel disease who underwent successful revascularization and returned at 3 months for coronary physiology assessments with bolus thermodilution. The prevalence of CMD (MRR <3) and the association between MRR and major adverse cardiovascular and cerebrovascular events (MACCEs) at 12 months were investigated. Results The median age of patients was 65 years, and 59.5% were men. At the 3-month follow-up, 56 patients (27%) had CMD (MRR <3.0). The number of MACCEs at 12 months was higher in patients with vs without CMD (48.2% vs 11.0%; P < 0.001). MRR was independently associated with 12-month MACCEs (HR: 0.45 per unit increase; 95% CI: 0.31-0.67; P < 0.001) and with stroke, heart failure, and poorer recovery in left ventricular systolic function. The areas under the receiver-operating characteristic curves for predicting MACCEs at 12 months with fractional flow reserve, coronary flow reserve (CFR), the index of microvascular resistance (IMR), and MRR were 0.609, 0.762, 0.781, and 0.743, respectively. The prognostic performance of CFR, IMR, and MRR were all comparable. Conclusions The novel parameter MRR is a prognostic marker of MACCEs in STEMI patients with a comparable performance to CFR and IMR. (Impact of TMAO Serum Levels on Hyperemic IMR in STEMI Patients [TAMIR]; NCT05406297)

Peroxynitrite, formed by the reaction of nitric oxide (NO · ) with superoxide anions (O[Formula: see text]·), may play a role in the pathophysiology of inflammation. The effects of 3-morpholinosydnonimine (SIN-1), a peroxynitrite generator, on the human bronchial epithelial cell line BEAS-2B, were examined. SIN-1 exposure resulted in cell death in a time- and dose-dependent manner. Depletion of intracellular glutathione increased the vulnerability of the cells. Pretreatment with Mn(III)tetrakis( N-methyl-4′-pyridyl)porphyrin (MnTMPyP) or hydroxocobalamin (HC), O[Formula: see text]· and NO · scavengers, respectively, reduced significantly SIN-1-induced cell death (18.66 ± 3.57 vs. 77.01 ± 14.07 or 82.20 ± 9.64, % cell viability SIN-1 vs. MnTMPyP or HC). Moreover, the mitogen-activated protein kinases (MAPK) p44/42 (ERK), p38, and p54/46 (JNK) were also activated in a time- and concentration-dependent manner. PD-98059 and SB-239063, specific inhibitors of ERK and p38 MAPK pathways, failed to protect cells against 1 mM SIN-1. However, PD-98059 partially inhibited (60% cell survival) SIN-1 effects at ≤0.25 mM, and this was increased with the inclusion of SB-239063. Therefore, MAPKs may mediate signal transduction pathways induced by peroxynitrite in lung epithelial cells leading to cell death.

Recent developments in intravascular imaging have permitted more accurate assessment of plaque vulnerability, while advances in computed tomographic coronary angiography (CTCA) have allowed noninvasive assessment of plaque morphology and identification of high-risk plaques. An invasive sealing of high-risk vulnerable lesions can be justified only if the endovascular devices used for this purpose are effective and safe. This chapter discusses the evidence supporting the role of Absorb bioresorbable vascular scaffolds (BVSs) in sealing high-risk plaques. Histology-based studies in porcine arteries have allowed detailed assessment of the vessel wall response following Absorb BVSs implantation. Scaffold implantation promotes the development of a thick layer of fibromuscular neo-tissue that has features associated with plaque stability while at long-term follow-up the deployed scaffold is fully resorbed liberating the vessel from its cage. The technical developments permitted detailed reconstruction and evaluation of the local hemodynamic micro-environment in segments implanted with Absorb BVS.

Background: Although bioresorbable scaffolds (BRS) may have important benefits, their deployment requires more aggressive lesion preparation compared to the best metallic DES due to different radial force and crossing profile. In addition, the benefits of post dilatation (PD) have not been systematically studied, with reports of fracture if the BRS expansion limits are exceeded by excessive PD. We sought to determine the impact of PD on clinical outcomes in a large cohort of patients treated with the Absorb only. Methods: We evaluated all consecutive patients enrolled in the multicenter, single arm ABSORB EXTEND Study through June 2013. The study allowed treatment of up to 2 coronaries (diameter 2.0 to 3.8mm) and the use of overlapping (lesion length ≤ 28mm). Patients with severe lesion calcification/tortuosity were excluded. Aggressive lesion pre dilatation (balloon to artery ratio of 0.9-1.0) was mandatory and PD was left to the operator’s discretion (if performed, non-compliant balloons up to 0.5mm lar...

Plaque disruption with superimposed thrombosis is the main cause of events such as the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death.2 It is suggested that increased plaque heat is a feature of vulnerable plaques.3 This heat might be caused by increased metabolic activity of inflammatory cells, such as macrophages, or by enzymatic extracellular matrix breakdown. Detection of heat could thus possibly lead to detection of vulnerable plaques.

We present a time series of 8–13 μm spectra and photometry for SN 2014J obtained 57, 81, 108, and 137 days after the explosion using CanariCam on the Gran Telescopio Canarias. This is the first mid-IR time series ever obtained for a Type Ia supernova (SN Ia). These observations can be understood within the framework of the delayed detonation model and the production of ∼0.6 M☉ of 56Ni, consistent with the observed brightness, the brightness decline relation, and the γ-ray fluxes. The [Co iii] line at 11.888 μm is particularly useful for evaluating the time evolution of the photosphere and measuring the amount of 56Ni and thus the mass of the ejecta. Late-time line profiles of SN 2014J are rather symmetric and not shifted in the rest frame. We see argon emission, which provides a unique probe of mixing in the transition layer between incomplete burning and nuclear statistical equilibrium. We may see [Fe iii] and [Ni iv] emission, both of which are observed to be substantially stronger than indicated by our models. If the latter identification is correct, then we are likely observing stable Ni, which might imply central mixing. In addition, electron capture, also required for stable Ni, requires densities larger than ∼1 × 109 g cm−3, which are expected to be present only in white dwarfs close to the Chandrasekhar limit. This study demonstrates that mid-IR studies of SNe Ia are feasible from the ground and provide unique information, but it also indicates the need for better atomic data.