Excellent post by KingsleyOldChap on Ihub, responding to our village idiot:
Xenon UV Pulse Efficacy Table raises questions
Tane61, I have been reading your very-well researched posts on the merits of the Xenex system - in particular, your statements claiming that it is capable of a rapid 100% kill of C.difficile in a hospital setting (my words, not yours, but it's what you were implying in good faith).
I have made a rather disconcerting observation about this particular technology's claims and I invite you to counter them:
As a recipient of a MSc in Quantum Fields and Fundamental Forces at the Imperial College London, I happen to have 'slightly more than a typical IHUBBER'S knowledge of light dispersion mechanics.'
My point in saying so is this: Having reviewed the metrics associated with the http://www.xenex.com/wp-content/uploads/2009/...f>Xenex Efficacy Table I noted with interest that the 4 Log (99.99%) C.difficile kill rates attributed to the Xenon UV Pulse machine were based on a spherical test field of just... SEVEN FEET!!!
Photon physics correctly suggests that allowing for the exponential dispersion of light rays proportionate to the distance traveled away from the light source, the lower the intensity and therefore the lower the efficacy.
I put it to you that the test has been somewhat curve-fitted for maximum result. Why? Because the science team at Xenex know all too well that if they ran the exact same trial based on a 26 ft spherical range as per some of their other tests, the results would "considerably less than 4 log".
I also put it to you that the decision by the research team to pick and choose the determined spherical range for each of the organisms and/or substrates tested "wreaks of curve-fitting" and fails to meet credible standards of modern trial protocols.
What is a "credible" test result? One where ALL organisms and/or substrates have been spherically range-tested at IDENTICAL DISTANCES. For example, all 20 test subjects could be spherically range-tested at say, 7 feet, 13 feet and 26 feet. That would at least give comparative data that (all other protocols being equal) would be acceptable.
Instead, what I see is a rather obvious attempt at "optimizing" the efficacy of the Xenon UV Pulse trial results.
But hey, who am I to say? Just my two pennies worth 
