Ultra-sonic Cell Lysis

[933467u at app_science.rgu.ac.uk]

To anyone who can help me,

I'm trying to lyse cells (E.coli and S. aureus) using ultra-sonic sound 
at 30kHz, perhaps a little higher, as an alternative to "beading".  Does 
anyone out there have any experience of this sort of thing?  Also can 
anyone tell me where I might find literature on this subject?

Thanks for your time folks,  Alan Mercer.