Front Matter

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• Inner Workings: Companies seek food safety using a microbiome approach
  If the approach is ever to replace more traditional food surveillance methods, researchers will have to find ways to sort through a vast amount of bacterial diversity. Image courtesy of Shutterstock/Alf Ribeiro.

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• Core Concept: Role player or cellular rubbish? Biologists debate the function of neutrophil extracellular traps
  Despite apparent abundance of NETs, researchers haven’t yet uncovered a specific gene or pathway responsible for their formation. Republished with permission of Rockefeller University Press.

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• Core Concept: Cryopreservation aims to engineer novel ways to freeze, store, and thaw organs
  Researchers want to revive damaged organs, improve the quality of human tissue models for drug discovery, and stretch the amount of time a transplant organ can be preserved. Image courtesy of Shutterstock/kalewa.

PNAS in the News

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• Boulder deposition by tsunamis and storms
  A study explores the origin of boulders deposited on cliffs in western Ireland and New Zealand’s North Island.
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• Fluid-driven artificial muscles
  Researchers report a fluid-driven artificial muscle that executes motions including bending, contraction, and torsion, with the ability to contract more than 90% of its initial length and generate stresses of approximately 600 kPa.
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• Environmental impacts of national diet recommendations
  Researchers report the environmental impacts of adopting nationally recommended diets.
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