Description of NMR Equipment

All experiments were performed in a 1.9-T horizontal bore magnet (Oxford Instruments, Oxford, UK) with a dear bore diameter of 31 cm. Magnetic field gradients were produced by a 12-cm id water-cooled gradient set (Resonance Research, Billerica, MA, USA), capable of a maximum output of 300 mT m-1, and were driven by Techron 7700 amplifiers (Techron Inc., Elkhart, IN, USA). Rf excitation was accomplished using either a quadrature driven birdcage coil (Morris Instruments, Ottawa, ON, Canada), or an 8-tum laboratory-built solenoid coil, driven by an ENI LPI-10 1000 W amplifier or a Matec Model 525 class-C amplifier. 

The authors thank Kevin Ewsuk, Chris DiAntonio, Terry Garino, Dale Zschiesche and Denise Bencoe of Sandia National Laboratories for fabricating the ceramics and performing the N2 adsorption measurements.a. F.M. and D. O. K. thank Dr. Doug Smith of Nanopore Inc. for fabrication of the fumed silica samples, and S. D. B. thanks Dr. Eiichi Fukushima of New Mexico Resonance and Dr. Mark 

Ishikawa, H. Yamaoka, Y. Harada, T. Fujii, T. Nagasawa 2002, Nature 146, 64. 

Groza 2002, in Nanostructured Materials - Processing, Properties and Potential Applications, ed. C. C. Koch, William Andrew Publishing, New York, chap. 4. 

Kossovsky, A. Gelman, E. Sponsler, H. Hnatyszyn 1994, (Surface modified nanocrystalline ceramics for drug delivery application), Biomaterials 15, 1201. 

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