Background (skip if you have been following this from the beginning): The stripy nanoparticle hypothesis was first proposed in Nature Materials in 2004 by the group of Professor Stellacci (then at MIT and now at the EPFL). This hypothesis now forms the basis of 23 articles by the same group, mostly published in high impact journals including Nature Materials, Nature Nanotechnology, Nature Communications, Science, Journal of the American Chemical Society, Small, etc: 1, 2, 3, 4, 5, 6, 7 , 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and 23. In November 2012, we published Stripy Nanoparticles Revisited which was followed by a response from Professor Stellacci.
Insoluble contradiction; In Stripy Nanoparticles Revisited (Fig S4, reproduced below), we pointed to a contradiction in the solubility reported for the same type of nanoparticles in two “stripy” articles: Jackson 2004 and Centrone 2008.
The response from Professor Stellacci was that the particles in both studies are different:
Stripy Nanoparticles Revisited claims that there are contradictions between our statements on particle solubility in Jackson 2004 and Centrone 2008 […] . Yet Jackson 2004 describes octanethiol, mercaptoproprionic acid-coated particles, Centrone 2008 describes octanethiol, mercaptoproprionate-coated particles, […]. Why would or should all of these particles behave the same way in terms of solubility […] given that the molecules that coat them are different? [emphasis mine]
Centrone 2008 focuses on the structure-solubility relationships of stripy nanoparticles in solvents of different polarities. The only measurement of structure in Centrone 2008 is in Fig 1. As shown below, Fig 1 in Centrone 2008 is data re-use (without attribution in the figure legend) from Jackson 2004.
There are only two possibilities:
1) The particles in Jackson 2004 are similar enough to those in Centrone 2008 to justify using the former STM images to discuss the latter structure and solubility. In this case, the data re-use is ‘ordinary’ self-plagiarism but the contradictions we noted in Stripy Nanoparticles Revisited remain to be explained.
Update 1 (15/02): Dave Fernig has contacted journal Editors about various data reuse in the stripy articles. Here is the response from PNAS:
“Thank you for bringing this to our attention. We have taken a look at the figures, and while they are similar, they are not identical. Also, the authors have referenced the earlier Nature publication in their PNAS article.”
After pointing out to PNAS that the images are indeed identical and directing them to check out the images side by side, with contrast, colour balance and scale adjusted, on Raphael’s blog, they came back on a much more positive note:
“Thank you for providing a link to Raphael Levy’s blog posting. Based on this additional information and clear explanation of the issue, we will follow up with the authors to discuss the matter.”
Update 2 (25/03): The PNAS article has now been ‘corrected’: the re-used image has been substituted for another one. It would therefore appear that the second possibility is more accurate.