Email Record: Colloidally Stable P(DMA-AGME)-Ale-Coated Gd(Tb)F(3):Tb(3+)(Gd(3+)),Yb(3+),Nd(3+) Nanoparticles as a Multimodal Contrast Agent for Down- and Upconversion Luminescence, Magnetic Resonance Imaging, and Computed Tomography