iche instruments (such as player pianos). This project investigated 309 historical documents, finding 258 contained writings about instrumental vibrato. Of those, 157 were presented as bibliographic annotations. The author found no consensus at any time in the history of Western art music between 1550-1940 that vibrato is wholly acceptable or wholly unacceptable.
Serial femtosecond crystallography requires reliable and efficient delivery of fresh crystals across the beam of an X-ray free-electron laser over the course of an experiment. We introduce a double-flow focusing nozzle to meet this challenge, with significantly reduced sample consumption, while improving jet stability over previous generations of nozzles. We demonstrate its use to determine the first room-temperature structure of RNA polymerase II at high resolution, revealing new structural details. Moreover, the double flow-focusing nozzles were successfully tested with three other protein samples and the first room temperature structure of an extradiol ring-cleaving dioxygenase was solved by utilizing the improved operation and characteristics of these devices.