But the orange blobby things remain a design classic, and are regularly trumpeted as a favourite by David Tennant.
But I can almost bet that working with those Roman numerals will always remain a design challenge.
Low exergy efficiencies remain a significant design consequence, but the system performance in terms of environmental impact and COP are comparable with, and in some cases better than, the performance of alternative technologies under the same conditions.
The following year, the sandal was discontinued, although the design remained a favourite in Germany and Italy - pre-trainers, any woman on her feet all day cherished a pair.
The sustained delivery of both hydrophobic and hydrophilic drugs from hydrogels has remained a challenge requiring the design and scalable production of complex multifunctional synthetic polymers.
DNA nanoparticles have been proposed for drug encapsulation and intracellular delivery, but it has remained a challenge to rationally design DNA nanoparticles for delivery of drug to human cancer cells, not to normal cells.
Lack of epithelial cell coverage has remained a persistent problem in the design of an artificial cornea.
Further enhancements and innovations over the last 20 years by a multitude of researchers across the field have greatly expanded this knowledge, but this approach called "orthogonal task design" has remained a fundamental component of many of these modern studies.
Until now, the clamshell design has remained a staple of mobile phones and women's compacts.
Nevertheless, movement pattern analysis found that despite the change in maze design, there remained a significant preference for visiting neighbouring arms (mean 1.5±± 0.03, t(7) = 17.13, p < 0.001).
