Assertion: collagen's structure | /r/HasProperty | imaged by electron microscopy
Facets:
value: in early 21st century
type: TEMPORAL
value: directly
type: MANNER
Source sentences:
text: The microfibrillar structure of collagen fibrils in tendon, cornea and cartilage was imaged directly by electron microscopy in the late 20th century and early 21st century.
text: The microfibrillar structure of collagen fibrils in tendon, cornea and cartilage has been directly imaged by electron microscopy.