Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
SEM images of vaterite toroids formed in the presence of D-Asp in different pH solutions (a–d; pH=6.46 for 10 d, pH=7.00 for 7 d, pH=9.00 for 3 d and pH=12.40 for 6 h, respectively), with all showing the same clockwise spiral growth direction (yellow arrows). Scale bars, 6 μm (a–c) and 2 μm (d).
