Mechanical properties of supramolecular polymeric materials cross-linked by donor–acceptor interactions

We prepare a tough elastomer with aromatic donor and acceptor molecules introduced on the same polymer side chain.

Mechanical and self-recovery properties of supramolecular ionic liquid elastomers based on host–guest interactions and correlation with ionic liquid content

Supramolecular materials have received considerable attention due to their higher fracture energy and self-recovery capability compared to conventional chemically cross-linked materials. Herein, we focus on the mechanical properties and self-recovery behaviours of supramolecular polymeric elastomers swollen with ionic liquid. We also gained insight into the correlation between ionic liquid content and mechanical properties. These supramolecular polymers with ionic liquid can be easily prepared from bulk copolymerization of the host–guest complex (peracetylated cyclodextrin and adamantane derivatives) and alkyl acrylates and subsequent immersion in ionic liquid such as 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The supramolecular polymeric elastomers showed a self-recovery ability, which the conventional chemically cross-linked elastomers with ionic liquid cannot achieve.

Supramolecular ionic liquid elastomers showed higher fracture energy than chemically cross-linked ionic liquid elastomers and also self-recovery ability.

Self-healing and shape-memory properties of polymeric materials cross-linked by hydrogen bonding and metal–ligand interactions

Polymeric materials were prepared by cross-linking them with two independent non-covalent interactions, namely hydrogen bonding and metal–ligand interactions.

Control of the threading ratio of cyclic molecules in polyrotaxanes consisting of poly(ethylene glycol) and α-cyclodextrins

We demonstrated a feasible method for providing polyrotaxanes (PRxs) with a controlled threading ratio of cyclic molecules and chain length of linear polymers by extending the linear polymers in the pseudo-PRx. This method gave PRxs with a lower threading ratio and a higher mobility of cyclic molecules compared to usual methods used previously with a high threading ratio. In addition, our PRx improved the thermal stability of the linear polymers in PRx despite the low threading ratio.

Continuing use of antithrombotic medications for patients with bleeding gastroduodenal ulcer requiring endoscopic hemostasis: a case-control study

OBJECTIVE

The aim of this study was to compare clinical characteristics and outcomes of bleeding gastroduodenal ulcer between patients taking antithrombotic medications and those not taking antithrombotic medications.

METHODS

We performed a case-control study of 346 patients with endoscopically verified bleeding gastroduodenal ulcer, which included 173 cases taking antithrombotic medications throughout peri-bleeding period and 173 age- and sex-matched controls not taking antithrombotic medications.

RESULTS

The cases showed less frequent Helicobacter pylori (H. pylori) infections (45.1% versus 60.7%, p = .005), more frequent duodenal location (31.8% versus 19.1%, p = .009), and more frequent rebleeding (13.9% versus 5.8%, p = .02) than the controls. Multivariate analysis revealed that duodenal location (odds ratio [OR] 3.01, 95% confidence interval [CI] 1.37-6.65) and use of antithrombotic medications (OR 2.47, 95% CI 1.13-5.77) were independent factors for rebleeding. However, there were no differences in clinical outcomes, including final successful endoscopic hemostasis, need for surgical intervention, and mortality between cases and controls. Thromboembolic events did not occur in any cases and controls during the periendoscopic period.

CONCLUSIONS

Low prevalence of H. pylori infection, frequent duodenal location, and high rebleeding rate are characteristics of patients with bleeding gastroduodenal ulcer under antithrombotic medications. Continuation of antithrombotic medications can be accepted for bleeding gastroduodenal ulcer.