After an anonymous tip about some papers by the Şen Research Group with possible duplicated graphs, I started digging around a bit more. And I found a couple more papers with duplications. And more. Quite a lot more. As of now, the SRG has 84 papers flagged on PubPeer. [Excel spreadsheet; PDF version]
The Şen Research Group
The Şen Research Group is led by Professor Dr. Fatih Şen, who worked two years at the US Massachusetts Institute of Technology as a postdoc. In 2013, he started his appointment at Kütahya Dumlupınar University in Kütahya, Turkey.
According to the SRG website, Şen has received the 2015 Science Academy Outstanding Young Scientist Award (TÜBA-GEBİP) (I could not find his name on the http://www.tuba.gov.tr/ website, though) and the “2017 Young Scientist Award” from the “Science Heroes Association” at a ceremony at the Pera Museum, Istanbul. The lab’s photo-gallery features Şen receiving several awards. There is also lots of cake. And a parakeet.
Şen is a very prolific author. As per Google Scholar, Dr. Fatih Şen has published 158 papers while working at Dumlupınar university, mostly describing the production of different types of nanoparticles. Most of these papers were published in the last two years. He cranked out about 50 papers in 2019 and 41 papers in the first half of 2020 alone.
One of Fatih Şen’s most prolific co-authors, and often the first author on his papers, is Betül Celik, who changed her name (keeping the same email address) to Betül Şen around 2017. She appears to have completed her Master’s around 2018, a year later, with Fatih Şen as her mentor.
Very similar graphs
PubPeer user Thallarcha Lechrioleuca (a pseudonym) was the first to find some trouble in XRD graphs in the Şen Research Group papers, some of which appear to look more similar than expected.
Thallarcha spotted more potential duplications. Even though the SRG papers describe different nanoparticles in each paper, made with e.g. either titanium, palladium, or rutheniume-copper alloy, the graphs showing the measured particle sizes were very similar. Here are some examples.
Very similar TEM photos
After looking at more papers by the Şen Research Group, each of which described a different type of nanoparticle, I started to notice that in addition to the similar graphs that Thallarcha had found, some Transmission Electron Microscopy (TEM) photos also looked unexpectedly similar.
TEM photos are used in these papers to show the appearance and size of the nanoparticles under a special type of microscope. Many of these TEM photos have a little inset showing the structure of the nanoparticles at a higher resolution. These High-Resolution TEM (HR-TEM) photos were made to show the nanoparticle size and structure in more detail, and they were used by the authors to measure the “atomic lattice fringe”, the distance between the molecules which are lined up in rows, giving the nanoparticles a striped appearance.
Here are four photos, each from a different paper, showing such TEM and HR-TEM photos. In addition to the very similar shape of the size distribution curve – as already noticed by Thallarcha – the small circular HR-TEM insets all appear to be showing the exact same photo.
Here are six instances of this photo, which I named “Inset 1” in more detail. Each photo comes from a different paper and represents a different type of nanoparticle. Yet, by rotating them a bit so that they all have about the same orientation, these photos look very similar.
After plowing through all 158 papers by the Şen Research Group, I found a whopping total of 42 papers that all have the “Inset 1” photo. You can find an example and a list of the first 30 papers containing Inset 1 here: DOI 10.1016/j.ijhydene.2018.03.175 – [PubPeer]
Another HR-TEM photo that occurred frequently is a photo I called – you guessed it – “Inset 2“. This photo was featured in 15 SRG papers. You can find an example and a list of the first 14 papers identified with Inset 2 here: DOI: 10.1016/j.ijhydene.2017.05.113 – [PubPeer]
Here are six of those instances:
Several other inset photos were found less frequently across the SRG papers. I found Inset 3 in five papers, and Insets 4 through 7 in two papers each.
There were also some cases where the larger, TEM photo was duplicated (not shown).
In addition to the XRD graphs which appeared to show highly similar areass across different lines, some of the papers appeared to show repetitive areas within NMR spectra. Those spectra usually show particular peaks, but the measurement in the other parts of the spectra is the background, the “noise”. The noise is not expected to be repetitive but rather random. Yet, some unexpected repeats were found within the same graphs.
Reporting the papers
All papers by the Şen Research Group with image concerns have been flagged on PubPeer. As of today, there are 84 SRG papers with PubPeer posts [Excel spreadsheet; PDF version], which were published in 23 journals since 2015. It will be quite some work for me to hunt down the contact information for each of these journals, but I will do this in the next day or so. Update: papers were reported to the journals and institute on August 8.
Of note, one third (28/84) of these papers have been published in Scientific Reports, and 19 of these were published in 2020 alone. Other journals that published relative large portions of this set are the International Journal of Hydrogen Energy (16 papers), the Journal of Molecular Liquids (7 papers), and Nano-Structures & Nano-Objects (5 papers).