Propolis recently been isolated from red propolis, and prenylated acids such as 4-hydroxy-3,5-diprenyl cinnamic acid have been documented. An analysis of propolis from Henan, China found sinapinic acid, isoferulic acid, caffeic acid, and chrysin, with the first three compounds demonstrating antibacterial properties. Also, Brazilian red propolis, largely derived from "Dalbergia ecastaphyllum" plant resin, has high relative percentages of the isoflavonoids 3-hydroxy-8,9-dimethoxypterocarpan and medicarpin. Other flavonoids commonly present include galangin and pinocembrin. Caffeic acid phenethyl ester (CAPE) is also a component of some varieties of propolis from New Zealand. Occasionally, worker bees will even gather various caulking compounds of human manufacture, when
Wood glue do not adhere well to hardened PVA glue. PVAs will creep under constant load. "Elmer's Glue-All" is an example of PVA adhesive. Aliphatic resin emulsion, commonly referred to as "yellow glue" or "carpenter's glue", has a similar use profile and relative ultimate strength as PVA. The two glues differ in grip characteristics before initial set, with PVAs exhibiting more slip during assembly and yellow glue having more initial grip. Brands include "Titebond" and "Lepage". Contact cement for wood veneers. Hot glue for temporary uses. Homemade glue for paper, wood, and internal uses. Several wood glues have poor "gap-filling" ability, meaning