X-Message-Number: 26548
Date: Thu, 7 Jul 2005 20:42:09 -0700 (PDT)
From: Doug Skrecky <>
Subject: 182'nd update on fly longevity experiments

     This is the 182'th update of my fly longevity experiments. Average
 temperature was 22.8 C during this run. Estimated maximal longevity using
 the formula (363 - T*11.2) is 108 days.
     This is a continuation of run #180, which tests lower dosages of
 cerium oxide nanoparticles, from Nanophase Technologies Corporation.
 Product name is NanoArc Cerium Oxide SGH, and product code #EXP0324.
     This time lower doses of nanoparticles turned out to be slightly
 toxic. Usually one would expect higher doses to be toxic, but this turned
 out not to be the case in run #180. An explanation for this curious
 toxicity inversion runs as follows. In aqueous solution high
 concentrations of nanoparticles may tend to aggregate, and this may have
 impeded their absorption.
     Cerium oxide nanoparticles are self regenerating antioxidants, and
 their failure to increase longevity in drosophila argues that either free
 radicals are not a causal factor in fly aging, or that these
 nanoparticles cannot penetrate into mitochondria, which are believed
 to be the prime site of free radical damage.

 Run #182                   Percent Survival on Day
 supplement              10 19 27 37 45 51 58 66 74 84
 _____________________________________________________
 control one             91 64 59 46 36 18 14  9  5  0
 control two             96 82 71 61 52 30 23  7  0  -
 cerium oxide 1/256 tsp  58 47 47 28 25  8  8  3  3  0
   "          1/256 tsp  83 65 65 48 40 30 13  8  0  -
   "          1/128 tsp  88 59 56 44 27 12  0  -  -  -
   "          1/128 tsp  71 56 49 37 32 12 10  5  0  -
   "          1/64 tsp   74 56 52 33 22 11  7  4  0  -
   "          1/64 tsp   80 50 48 30 23 15  3  3  0  -
   "          1/32 tsp   79 54 50 46 29 18 14  7  0  -
   "          1/32 tsp   90 52 41 41 28 10  3  0  -  -

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