PREFIX arg: <http://purl.obolibrary.org/obo/> 
PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
PREFIX v:   <http://www.w3.org/2006/vcard/ns#> 
PREFIX vivo: <http://vivoweb.org/ontology/core#> 

CONSTRUCT {
    ?vcard v:hasName _:name .
    _:name a v:Name .
    _:name v:givenName ?firstName .
    _:name vivo:middleName ?middleName .
    _:name v:familyName ?lastName .
} WHERE {
     ?s arg:ARG_2000028 ?vcard .
    OPTIONAL {
        ?s foaf:firstName ?firstName .
        BIND("yes" as ?test)
    } 
    OPTIONAL {
        ?s foaf:lastName ?lastName .
        BIND("yes" as ?test)
    } 
    OPTIONAL {
        ?s vivo:middleName ?middleName 
        BIND("yes" as ?test)
    } 
    FILTER(bound(?test))
}