This work estimates that if the growth of polymer production continues at its current rate of 5% each year, the current annual production of 395 million tons of plastic will exceed 1000 million tons by 2039. Only 9% of the plastics that are currently produced are recycled while most of these materials end up in landfills or leak into oceans, thus creating severe environmental challenges. Covalent adaptable networks (CANs) materials can play a significant role in reducing the burden posed by plastics materials on the environment because CANs are reusable and recyclable. This review is focused on recent research related to CANs of polycarbonates, polyesters, polyamides, polyurethanes, and polyurea. In particular, trends in self-healing CANs systems, the market value of these materials, as well as mechanistic insights regarding polycarbonates, polyesters, polyamides, polyurethanes, and polyurea are highlighted in this review. Finally, the challenges and outlook for CANs are described herein.
Percutaneous coronary intervention (PCI) is 40 years old this year. From its humble beginnings of experimental work, PCI has transitioned over years with coronary artery stenting now a standard medical procedure performed throughout the world. Areas covered: The conversion from plain old balloon angioplasty (POBA) to the present era of drug eluting stents (DES) has been driven by many technological advances and large bodies of clinical trial evidence. The journey to present day practice has seen many setbacks, such as acute vessel closure with POBA; rates of instant restenosis with bare metal stents (BMS) and more recently, high rates of stent thrombosis with bioabsorbable platforms. This work discusses POBA, why there was a need for BMS, the use of inhibiting drugs to create 1 generation DES, the change of components to 2 generation DES, the use of absorbable drug reservoirs and platforms, and possible future directions with Prohealing Endothelial Progenitor Cell Capture Stents. Expert commentary: This paper reviews the evolution from the original pioneering work to modern day practice, highlighting landmark trials that changed practice. Modern day contemporary practice is now very safe based on the latest drug eluting stents and supported by large datasets.
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