A word or phrase whose content/subject matter has special semantics or content-related significance. In print or display, such content is likely to be treated differently, for example, given a special typographic style such as italics or background shading.
The content-type attribute can be used to identify the subject or type of content that makes this word or phrase semantically special and, therefore, to be treated differently. For example, this attribute could be used to identify a drug name, company name, or product name. It could be used to define systematics terms, such as genus, family, order, or suborder. It could also be used to identify biological components, such as gene, protein, or peptide. It could be used to name body systems, such as circulatory or skeletal. Therefore, values may include information classes, semantic categories, or types of nouns such as “generic-drug-name”, “genus-species”, “gene”, “peptide”, “product”, etc.
<!ELEMENT named-content (#PCDATA %named-content-elements;)* >
Any combination of:
<addr-line> Address Line; <aff> Affiliation; <alt-title> Alternate Title; <anonymous> Anonymous; <article-title> Article Title; <attrib> Attribution; <bold> Bold; <book-title> Book Title; <chem-struct> Chemical Structure (Display); <citation> Citation; <collab> Collaborative (Group) Author; <collection-name> Collection Name; <comment> Comment in a Citation; <conf-loc> Conference Location; <conf-name> Conference Name; <conf-sponsor> Conference Sponsor; <contract-num> Contract Number; <contract-sponsor> Contract Sponsor; <copyright-statement> Copyright Statement; <corresp> Correspondence Information; <def-head> Definition List: Definition Head; <degrees> Degree(s); <disp-formula> Formula, Display; <edition> Edition, Cited; <etal> Et Al; <ext-link> External Link; <fax> Fax Number: in an Address; <font> Font; <given-names> Given (First) Names; <gov> Government Report, Cited; <grant-num> Grant Number; <grant-sponsor> Grant Sponsor; <inline-formula> Formula, Inline; <inline-supplementary-material> Inline Supplementary Material; <institution> Institution Name: in an Address; <issue> Issue Number; <italic> Italic; <kwd> Keyword; <label> Label (Of a Figure, Reference, Etc.); <meta-name> Metadata Data Name for Custom Metadata; <meta-value> Metadata Data Value for Custom Metadata; <monospace> Monospace Text (Typewriter Text); <named-content> Named Special (Subject) Content; <on-behalf-of> On Behalf of; <overline> Overline; <p> Paragraph; <patent> Patent Number, Cited; <phone> Phone Number: in an Address; <prefix> Prefix; <preformat> Preformatted Text; <publisher-loc> Publisher’s Location; <publisher-name> Publisher’s Name; <related-article> Related Article Information; <related-object> Related Object Information; <role> Role or Function Title of Contributor; <sans-serif> Sans Serif; <sc> Small Caps; <series> Series; <sig> Signature; <sig-block> Signature Block; <source> Source; <std> Standard, Cited; <strike> Strike Through; <sub> Subscript; <subject> Subject Grouping Name; <subtitle> Subtitle; <suffix> Suffix; <sup> Superscript; <supplement> Supplement Information; <surname> Surname; <target> Target of an Internal Link; <td> Table Data Cell (XHTML table model); <term> Definition List: Term; <term-head> Definition List: Term Head; <th> Table Header Cell (XHTML table model); <title> Title; <trans-source> Translated Source; <trans-subtitle> Translated Subtitle; <trans-title> Translated Title; <underline> Underline; <uri> Uniform Resource Indicator (URI); <verse-line> Line of a Verse; <volume> Volume Number; <volume-id> Volume Identifier; <xref> X(cross) Reference
... <p>Knowing the secondary structure of a protein can also be a useful prelude to viewing the 3D structure of the molecule. The secondary structure can be viewed easily by first selecting the <named-content content-type="book-spec-emph">Protein</named-content> link to the left of the desired chain in the graphic display. Finding oneself in Entrez Protein, selecting <named-content content-type="book-spec-emph">Graphics</named-content> in the Display pull-down menu presents secondary structure diagrams for the molecule.</p> ...