The carving on my Dayak Mandau inspired me to research betel nut. Our results were published this week. This is the journal article with a picture of the sword.
http://journals.plos.org/plosone/art...l.pone.0140907
This an editorial which is written more for the lay-person:
http://www.omicsonline.org/open-acce...5-1000e130.pdf
This is a press release from my University:
https://ufhealth.org/news/2015/resea...ions-worldwide