PMC:7784787 / 8325-8549 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T71","span":{"begin":0,"end":109},"obj":"Sentence"},{"id":"T72","span":{"begin":110,"end":224},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"(A) the unmasked dummy, (B) three-layer mask with middle filter layer removed, (C) single-layer textile mask. Bottom row: (D) CE marked FFP1 personal protective equipment mask, (E) CE marked Type 2 medical mask, (F) bandana."}