{ "items" : [
    { "id" : "http://ns.inria.fr/covid19/PMC7110321#title"
      "properties" : {
        "http://purl.org/dc/terms/subject" : [ "Proteins",
          "Cell signaling",
          "Sodium",
          "Ligands (biochemistry)",
          "Glycoproteins",
          "Sodium minerals",
          "Biomolecules",
          "Chemical bonding"] } } }
