Building programmable jigsaw puzzles with RNA

One challenge in supramolecular chemistry is the design of versatile, self-assembling building blocks to attain total control of arrangement of matter at a molecular level. We have achieved reliable prediction and design of the three-dimensional structure of artificial RNA building blocks to generate molecular jigsaw puzzle units called tectosquares. They can be programmed with control over their geometry, topology, directionality, and addressability to algorithmically self-assemble into a variety of complex nanoscopic fabrics with predefined periodic and aperiodic patterns and finite dimensions. This work emphasizes the modular and hierarchical characteristics of RNA by showing that small RNA structural motifs can code the precise topology of large molecular architectures. It demonstrates that fully addressable materials based on RNA can be synthesized and provides insights into self-assembly processes involving large populations of RNA molecules.     

Quality of baked potatoes as influenced by baking and holding methods

Russet Burbank potatoes baked with and without wrapping were held at different temperatures to determine the effect of the procedures on cooking quality. Unwrapped and foil-wrapped tubers did not differ in mealiness, color, and extent of off-flavor devlopment when judged at the time of doneness. A holding period of 1 hr for both treatments resulted in a marked deterioration of quality that progressed during a second hour of holding. Unwrapped potatoes showed greater textural impairment after holding and were significantly cooler than foil-wrapped potatoes treated in the same manner. Although foil-wrapped potatoes remained hot during the holding period, low mealiness scores, off-flavors, and discoloration showed they were substandard in quality. Quality deterioration was minimized when pierced foil or a paper bag was used as wrapping during baking and holding, but the serving temperature was low for the paper-wrapped tubers. If baked potatoes must be held before serving, it is recommended that they be wrapped in pierced foil prior to baking and that they be held at 200 F for as short a time as possible.