Table 5 Material table data fields.

From: An EPA database on the effects of engineered nanomaterials-NaKnowBase

 

Description

MaterialID

Unique identification code for the tested material

publication_DOI

Reference to DOI of source publication

CoreComposition

Primary composition of the tested material

ShellComposition

Primary composition of a shell applied to the core substance

CoatingComposition

Primary composition of material applied as a coating to the core substance

SynthesisMethod

How the ENM was made: “Original method” if original, DOI of publication if a method is cited from a publication, or name of method if a common name is used.

SynthesisDate

When the ENM was made

CASRN

CAS Registry Number of core composition

Supplier

Source of the material

ProductNumber

Manufacturer’s product number

LotNumber

Production lot number

ValueApproxSymbol/ Unit/Uncertainty/Low/High/Method

• OuterDiameter

Seven separate fields capture summary measurement information for each of the nine ENM characteristics in the bulleted list, totalling 63 fields. The field “OuterDiameterValue” is used for non-nanotube particle size measurements. ApproxSymbol captures characters used to qualify measurements that lack precision, typically due to limitations of the instrumentation used for measurement (e.g. <, >, ~). Low and High are defined by Uncertainty. If Uncertainty describes a concept with two numbers (e.g. range), Low and High hold the endpoints. If Uncertainty requires a single value (e.g. standard deviation), the value is stored in Low and High is left blank.

• InnerDiameter

• Length

• Thickness

• SurfaceArea

• SizeDistribution

• Purity

• HydrodynamicDiameter

• SurfaceCharge

Shape

The shape of the original particle

medium_MediumID

Reference to Medium ID of the medium this material was examined in

medium_publication_DOI

Reference to DOI of source publication

ShapeInMedium

Particle shape in identified medium

Solubility

Particle solubility in medium

  1. Each entry in the material table was uniquely identified by the DOI of the source publication and an incrementing number to account for publications that studied multiple materials. Fields in this table address ENM composition, metadata (i.e., manufacturing information), and other physicochemical properties including, but not limited to, those addressed on EPA forms for submission of novel nanomaterials for registration under the Toxic Substances Control Act (TSCA) (https://www.regulations.gov/document?D=EPA-HQ-OPPT-2009-0686-0015). Note that companies were not required to generate data for these fields in order to submit TCSA registrations, only to report such data if available.
  2. Core Composition was defined as the base material of the ENM, and any additions to the structure were recorded in Shell Composition or Coating Composition. Synthesis Method refers to a common method name or the DOI for a publication available. Core Composition was defined as the base material of the ENM, and any additions to containing the methodology. Several fields associated with large-batch or industrial scale ENM manufacturing are included: Synthesis Date, Supplier, Product Number, Lot Number, and if applicable, the Chemical Abstracts Service Registry Number (CASRN). Shape recorded the typical shape of the material, which was important for materials like carbon that varied wildly (e.g. sheets, tubes, or a simple bulk form). If the material was suspended in a medium, that medium was referenced by DOI and Medium. This allowed for important rows about medium-specific qualities, such as Shape in Medium or Solubility, to be captured. Specifically, NKB captures many quantitative characteristics for a nanomaterial, e.g. outer diameter, inner diameter, length, thickness, surface area, size distribution, purity, hydrodynamic diameter, and surface charge. Many publications report these data using summary statistics without raw data. Therefore, each ENM characteristic was described using a set of seven fields capable of capturing raw and processed data: Value ApproxSymbol, Unit, Uncertainty, Low, High, and Method. Average contained either the raw or average numeric value reported for a measurement. ApproxSymbol captured any qualifying characters (e.g. <, >, ~) denoting measurements that lacked precision, typically due to a limitation of the machine used for measurement. Unit contained the physical unit for the measurement, using standard scientific abbreviations when possible. Raw data were reported using these first three fields along with Method. The Uncertainty, Low, and High fields are used in combination to describe the spread or distribution of processed data. The Uncertainty field held statistical terms such as “range” or “standard deviation”. If the term required two endpoints, Low and High held the numeric values for those respective endpoints. For example, the Low and High of an “interquartile range” would be the first and third quartile values, respectively. If the “Uncertainty” statistic term required only one value (e.g. standard deviation), the value was recorded in Low. Finally, the technique or method used to produce the raw or processed measurements was recorded in Method (e.g., transmission electron microscopy).
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