3 research outputs found
Water-Blown Polyurethane Foams Showing a Reversible Shape-Memory Effect
Water-blown polyurethane (PU) foams are of enormous technological interest as
they are widely applied in various fields, i.e., consumer goods, medicine,
automotive or aerospace industries. The discovery of the one-way shape-memory
effect in PU foams provided a fresh impetus for extensive investigations on
porous polymeric actuators over the past decades. High expansion ratios during
the shape-recovery are of special interest when big volume changes are
required, for example to fill an aneurysm during micro-invasive surgery or
save space during transportation. However, the need to program the foams
before each operation cycle could be a drawback impeding the entry of shape-
memory polymeric (SMP) foams to our daily life. Here, we showed that a
reversible shape-memory effect (rSME) is achievable for polyurethane water-
blown semicrystalline foams. We selected commercially available crystallizable
poly(ε-caprolactone)-diols of different molecular weight for foams synthesis,
followed by investigations of morphology, thermal, thermomechanical and shape-
memory properties of obtained compositions. Densities of synthesized foams
varied from 110 to 180 kg∙m−3, while peak melting temperatures were
composition-dependent and changed from 36 to 47 °C, while the melting
temperature interval was around 15 K. All semicrystalline foams exhibited
excellent one-way SME with shape-fixity ratios slightly above 100% and shape-
recovery ratios from the second cycle of 99%. The composition with broad
distribution of molecular weights of poly(ε-caprolactone)-diols exhibited an
rSME of about 12% upon cyclic heating and cooling from Tlow = 10 °C and Thigh
= 47 °C. We anticipate that our experimental study opens a field of systematic
investigation of rSMEs in porous polymeric materials on macro and micro scale
and extend the application of water-blown polyurethane foams to, e.g.,
protective covers with zero thermal expansion or even cushions adjustable to a
certain body shape. View Full-Tex
Ticagrelor in patients with diabetes and stable coronary artery disease with a history of previous percutaneous coronary intervention (THEMIS-PCI) : a phase 3, placebo-controlled, randomised trial
Background:
Patients with stable coronary artery disease and diabetes with previous percutaneous coronary intervention (PCI), particularly those with previous stenting, are at high risk of ischaemic events. These patients are generally treated with aspirin. In this trial, we aimed to investigate if these patients would benefit from treatment with aspirin plus ticagrelor.
Methods:
The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS) was a phase 3 randomised, double-blinded, placebo-controlled trial, done in 1315 sites in 42 countries. Patients were eligible if 50 years or older, with type 2 diabetes, receiving anti-hyperglycaemic drugs for at least 6 months, with stable coronary artery disease, and one of three other mutually non-exclusive criteria: a history of previous PCI or of coronary artery bypass grafting, or documentation of angiographic stenosis of 50% or more in at least one coronary artery. Eligible patients were randomly assigned (1:1) to either ticagrelor or placebo, by use of an interactive voice-response or web-response system. The THEMIS-PCI trial comprised a prespecified subgroup of patients with previous PCI. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, or stroke (measured in the intention-to-treat population).
Findings:
Between Feb 17, 2014, and May 24, 2016, 11 154 patients (58% of the overall THEMIS trial) with a history of previous PCI were enrolled in the THEMIS-PCI trial. Median follow-up was 3·3 years (IQR 2·8–3·8). In the previous PCI group, fewer patients receiving ticagrelor had a primary efficacy outcome event than in the placebo group (404 [7·3%] of 5558 vs 480 [8·6%] of 5596; HR 0·85 [95% CI 0·74–0·97], p=0·013). The same effect was not observed in patients without PCI (p=0·76, p interaction=0·16). The proportion of patients with cardiovascular death was similar in both treatment groups (174 [3·1%] with ticagrelor vs 183 (3·3%) with placebo; HR 0·96 [95% CI 0·78–1·18], p=0·68), as well as all-cause death (282 [5·1%] vs 323 [5·8%]; 0·88 [0·75–1·03], p=0·11). TIMI major bleeding occurred in 111 (2·0%) of 5536 patients receiving ticagrelor and 62 (1·1%) of 5564 patients receiving placebo (HR 2·03 [95% CI 1·48–2·76], p<0·0001), and fatal bleeding in 6 (0·1%) of 5536 patients with ticagrelor and 6 (0·1%) of 5564 with placebo (1·13 [0·36–3·50], p=0·83). Intracranial haemorrhage occurred in 33 (0·6%) and 31 (0·6%) patients (1·21 [0·74–1·97], p=0·45). Ticagrelor improved net clinical benefit: 519/5558 (9·3%) versus 617/5596 (11·0%), HR=0·85, 95% CI 0·75–0·95, p=0·005, in contrast to patients without PCI where it did not, p interaction=0·012. Benefit was present irrespective of time from most recent PCI.
Interpretation:
In patients with diabetes, stable coronary artery disease, and previous PCI, ticagrelor added to aspirin reduced cardiovascular death, myocardial infarction, and stroke, although with increased major bleeding. In that large, easily identified population, ticagrelor provided a favourable net clinical benefit (more than in patients without history of PCI). This effect shows that long-term therapy with ticagrelor in addition to aspirin should be considered in patients with diabetes and a history of PCI who have tolerated antiplatelet therapy, have high ischaemic risk, and low bleeding risk