Singapore National Research Foundation under NRF-RFNational Research Foundation, Singapore [NRF-RF2010-07]; A*Star SERC PSFAgency for Science Technology & Research (ASTAR) [1321202101]; MOEMinistry of Higher Education & Scientific Research (MHESR) [MOE2012-T2-2049, ARC 26/13, MOE2013-T2-1-034, RG 61/12, RGT18/13, RG5/13]; Start-Up Grant in Singapore [M4080865.070.706022]; National Research Foundation, Prime Minister's Office, SingaporeNational Research Foundation, Singapore