This blog post is not intended to be an allegation of misconduct. I am just wondering about some unclarities and unexpected similarities in a set of papers.
Living on planet Mars
Ever since the first human landed on the moon in 1969, many people have become fascinated by the idea to live on another planet. The best candidate for “Earth 2.0” is planet Mars, because of its proximity to Earth and presence of ice that could be converted to water.
Even so, Mars would still not be a great place to live on by human standards, with a chilly average temperature of −63 °C (−81 °F), gravity of only one third compared to Earth, and atmosphere with only 0.13% oxygen. Still, these conditions are better than on most other planets.
There are several professional institutions that explore the possibilities of colonizing planet Mars, such as NASA’s Mars Exploration Program.
The Mars Society, driven by a group of volunteers, takes this one step further, by sending crews of volunteers to the Mars Desert Research Station (MDRS) to simulate life on Mars. The MDRS is a Mars-analog site in the Utah desert with several structures where people can sleep, perform indoor experiments, or explore the surroundings while dressed in space suits and riding on cute little ATVs.
Six-person crews of volunteers typically spend 2 weeks in the MDRS, and perform various experiments to test the effect of space conditions on humans and other forms of life. Each “mission” will write detailed reports and publish these on the Mars Society website.
The Space Dentist
One such Mars enthusiast is a dentist from India who specializes in aeronautical dentistry. He participated in three of the MDRS missions, and according to his profile page on Omics International (a publisher included in Beall’s List of Predatory Publishers), is the Program Director and Associate Professor of Aeronautic Dentistry at the Kepler Space Institute, and the author of over 100 journal papers.
This author has been the topic of several interesting blog posts, including “Space Dentist, sign of the time, Space Dentist, so outta line” and “On the Internet no-one knows you’re a dog barking mad” on Riddled by Smut Clyde, an article on Flaky Academic Journals, and “Proven plagiarism” extracts paper on keeping teeth healthy in outer space” on Retraction Watch.
The space dentist also lists in his bios to be the Editor in Chief of several journals, although Google only reports one journal. That journal appears to have been named after himself: the JBR Journal of Translational Space dentistry, Medicine and Exploration.
Mars Simulation papers
The aeronautical dentist has several publications on the effect of Mars Simulation on the human body. He participated three times in MDRS missions, and during each of these 2 week periods, he performed a range of experiments on the 6-member MDRS crews. Here are his research papers on this topic:
- Mental and Physical Workload, Salivary Stress Biomarkers and Taste Perception: Mars Desert Research Station Expedition (2012): 12 crew members
- Salivary amylase and stress during stressful environment: Three Mars analog mission crews study (2012):
- Stress, Workload and Physiology Demand During Extravehicular Activity: A Pilot Study (2012): 6 crew members
- Working hours, sleep, salivary cortisol, fatigue and neuro-behavior during Mars analog mission: Five crews study (2012): 30 crew members
- Wound Healing and Mucosal Immunity During Short Mars Analog Environment Mission: Salivary Biomarkers and Its Clinical Implications (2012): 2 crew members
- Association Between Stress, Sleep Quality and Temporomandibular Joint Dysfunction: Simulated Mars Mission (2013): 24 crew members
- Periodontal status, salivary immunoglobulin, and microbial counts after short exposure to an isolated environment (2013): 12 crew members.
Remarkable similarities between MDRS studies
These MDRS studies vary in number of crew members and expeditions that were included. It is therefore very unexpected that the age range and means of 5 of these studies are all very similar. In addition, the intake of calories, calcium, sodium, potassium, and ad libitum water means are also remarkably similar between these papers. I raised some questions about these studies on PubPeer.
Not only do the age and dietary parameters look remarkably different between these studies, there are textual similarities too. Text from several of these papers is unexpectedly similar to text from older papers written by other researchers.
And the similarities do not stop there. There is also a remarkably high similarity between text as well as measurements from “Wound healing and mucosal immunity during short Mars analog environment mission: salivary biomarkers and its clinical implications” to that of Marucha PT et al. from 1998 called “Mucosal wound healing is impaired by examination stress“.
In addition to his studies performed on MDRS crew members, the space dentist et al. has written several papers about the effects of microgravity on the human body, another interesting aspect that might be relevant for Martian colonization.
Microgravity is often tested in the lab by having human volunteers lie on a bed that is tilted backwards a bit, so that the feet are raised. These experiments are called “Head-down-tilt” (HDT).
In HDT experiments, persons would have to lie for days or even weeks on a tilted bed without getting up at all, even to eat or go to the bathroom. Not surprisingly, volunteers for these experiments are hard to find. In fact, the German Space Agency (DLR) is currently looking for participants for a 60-day bed rest study, and is offering 16,500 Euros ($18,500). Pancakes will be provided.
One would expect that such microgravity experiments are carefully planned, executed, and described. And that scientists would not subject volunteers to such experiments to just measure one small effect.
The aeronautical dentist team has written several papers in which volunteers were subjected to microgravity. Surprisingly, the experimental conditions are very vaguely described. Several of his papers do not clearly state if the volunteers were on the tilted bed for only 8h per day (allowed to go home at night), or if they had to stay on the bed continuously. In addition, each of these studies measured only a couple of clinical parameters.
- Effect of Microgravity on Oral Cavity : Mission to Mars (2009): 20 males, 8h HDT, 1 day.
- Anti-oxidation actions of curcumin in two forms of bed rest: oxidative stress serum and salivary markers (2010): 20 males, 8h HDT, 10 days, measurements of salivary and serum markers.
- Bone mineral density, bone mineral content, gingival crevicular fluid (matrix metalloproteinases, cathepsin K, osteocalcin), and salivary and serum osteocalcin levels in human mandible and alveolar bone under conditions of simulated microgravity (2010): 10 males, 10 females, HDT duration per day not clear, 3 weeks. Measured bone density/content, gingival, salivary, serum markers.
- Salivary stress markers and psychological stress in simulated microgravity: 21 days in 6° head-down tilt (2011): 12 males, continuous HDT with video monitoring, 21 days. Measured psychological wellness and salivary markers.
- Evaluation by an aeronautic dentist on the adverse effects of a six-week period of microgravity on the oral cavity (2011): 10 males, HDT duration continuously? (not clear), 6 weeks. Measured facial sensation, jaw and tongue movement, salivary markers.
- Effect of Simulated Microgravity on Salivary and Serum Oxidants, Antioxidants, and Periodontal Status (2011): 20 males, continuous HDT with video monitoring, 60 days. Measured salivary and serum markers.
- Effect of Short Duration Simulated Microgravity on Effectiveness of Local Anesthesia (2012) (RETRACTED): 51 males, continuous HDT, 10 days. Measured efficacy of lidocaine anesthesia.
- Salivary Stress Markers, Depression, Mood State and Back Pain in Healthy Men in Two Bed Rest Conditions: Validation of Two Models for Human Space Flight (2013): 10 males, continuous HDT, 20 days. Measured back pain, headache, alertness, calmness, and saliva markers.
- Bone Mineral Density (BMD), Bone Mineral Content (BMC), and MMP-8 and MMP-9 Levels in Human Mandibular and Alveolar Bone: A Study in Simulated Microgravity (2013): 10 males, 10 females, HDT duration per day not clear from abstract, 3 weeks. Measured bone mineral density and content and gingival crevicular fluid. Sounds very similar to study #3, but behind paywall.
Remarkable similarities between microgravity papers
Even though each paper appears to describe a different study (different number of volunteers or length of experiment), there are remarkable similarities between age, weight, and height of the volunteers.
In addition, there are remarkable similarities between data presented in Effect of Microgravity on Oral Cavity : Mission to Mars (2009; 20 men, 1 day of microgravity) and Evaluation by an aeronautic dentist on the adverse effects of a six-week period of microgravity on the oral cavity (2011; 10 men, 6 weeks of microgravity).
One of the HDT papers, Effect of Short Duration Simulated Microgravity on Effectiveness of Local Anesthesia (2012), has been retracted in 2013. The retraction notice reads:
The journal and publisher would like to inform the readers that this paper has been retracted. The journal had been informed by one of the co-authors, Jack van Loon, that he had noticed after publication that Fig. 1 of the article had been taken from the internet and masked, giving the wrong impression that it is showing the setup used in the studies discussed in the paper. Further investigations by the publisher revealed a significant textual overlap with the paper “Srisurang et al., Journal of Investigative and Clinical Dentistry (2011), 2, 23–28”.Retraction of Original Article: Microgravity Sci. Technol. (2012) DOI 10.1007/s12217-012-9321-x
Study locations and authors affiliations
For these microgravity studies, which must have taken a lot of time to prepare and execute, it is also not always clear where these experiments were performed. The first author is often listed as affiliated with the “JBR Institute of Health Education and Research and Technology Society” in India, and/or at the Kepler Space Institute (sometimes listed as Kepler Space University) in the US. The affiliations of the co-authors vary from the Catholic University of Leuven, Vrije Universiteit Amsterdam, European Space Agency Noordwijk, or at NASA.
IRB approval, approval needed to ensure ethical recruitment and treatment of volunteers in research studies, is sometimes mentioned to have been granted by the “Jain Diagnostic Center” in New Delhi, or not mentioned at all. With experiments such as prolonged stays in a tilted bed, which could have some damaging effect on a volunteer’s body, one would hope that checking for appropriate IRB approval would have been part of a reviewer’s or editors checklist.
The mysterious JBR Institute is otherwise not listed anywhere on the interwebs.
Of particular note, the first author’s affiliation with the Kepler Space Institute as mentioned on several of his papers appears incorrect. I wrote to the KSI, and they answered me that, although they had heard of this person, he was in no way affiliated with the KSI. “He has never worked here, does not currently work here, and – based on the information you gave us – will never work here“, a KSI representative told me.
Some of the aeronautical dentist’s other work is characterized by percentages that appear to be wrong. For example, in a group of 20 people, you might find that 10% (n=2) people might have a PhD. A percentage of 10.8% seems a bit hard to explain.
Yet, in this paper, “sTNF-R Levels: Apical Periodontitis Linked to Coronary Heart Disease” (2017), the authors report percentages of 10.8, 30.1, and 45.9 in a group of 20 people.
These hard-to-understand percentages also appear in “Possible relationship between periodontitis and dementia in a North Indian old age population: a pilot study” (2012).
Both of these papers also appear to contain textual similarities.
The space dentist has written several papers on microgravity and simulated Mars missions that contain unexpected similarities in volunteer characteristics and measurements between different experiments. In addition, there are textual similarities to papers by other groups, as well as unclear or incorrect institutional affiliations.
I will write to the Editors and Research Integrity Officers of the involved journals and institutions to ask for a investigation of the data presented in these papers.
Update May 27: I just wrote to the Editors of all journals in which these papers appeared, as well as the Research Integrity Officers of the involved institutions to report a total of 18 papers from the same author with concerning data or textual similarities.