Nano-constraints on the spatial anisotropy of the Gravitational Constant
  We present constraints from various experimental data that limit any spatial anisotropy of the Gravitational constant to less than a part per billion or even smaller. This rules out with a wide margin the recently reported claim of a spatial anisotropy of G with a diurnal temporal signature. 
C. S. Unnikrishnan, G. T. Gillies