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.
Representative negative ion mode DESI spectra of human tumor tissues. a) Sample G2, diffuse astrocytoma (WHO grade II), b) sample G4, anaplastic astrocytoma (WHO grade III) and c) sample G5, glioblastoma (WHO grade IV). See text for lipid abbreviations.
