There are multiple definitions:

1. upstream activated sequence(English)

   • JNK, RBP
   • Biology

2. unmanned aircraft system(English)

   • see “drone”
   • Aviation medicine

3. unprocessed Angelica sinensis(English)

   • APH, AS, CTX, GC-MS
   • Alternative medicine, Pharmacology / pharmaceutics
   • https://doi.org…jep.2012.11.018