Substantial metabolic activity of human brown adipose tissue during warm conditions and cold-induced lipolysis of local triglycerides by Weir, G, Ramage, L, Akyol, M, Rhodes, J, Kyle, C, Fletcher, A, Craven, T, Wakelin, S, Drake, A, Gregoriades, M, Ashton, C, Weir, N, van Beek, E, Karpe, F, Walker, B, Stimson, R