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Additional Information

Competing Interests

No competing interests.

Author Contributions

Laura Hokkanen analyzed the data, wrote the paper.

Jyrki Launes analyzed the data, wrote the paper.

Katarina Michelsson conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools.

Human Ethics

The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):

Ethical Review Board of the Helsinki and Uusimaa hospital district in May 2013 (number 147/13/3/00/2013).


No external funding for the current study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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