The Semantic MEDLINE Database (SemMedDB) is a repository of semantic predications (subject-predicate-object triples) extracted by SemRep, a semantic interpreter of biomedical text. SemMedDB currently contains information about approximately 94.0 million predications from all of PubMed citations (about 27.9 million citations, as of December 31 2017) and forms the backbone of the Semantic MEDLINE application.
For details about the SemMedDB schema, click here.
In early 2011, we conducted a gold standard annotation study in which we annotated with semantic predications a set of 500 sentences randomly selected from MEDLINE abstracts. The results are mainly intended to serve as an evaluation testbed for SemRep. They can also be used by other information extraction systems based on UMLS domain knowledge. The study consisted of three phases: a) the practice phase, b) the main annotation phase, and c) the adjudication phase.
Here, we present two sets of annotations from the main phase as well as the adjudicated gold standard. For further details, please refer to our BMC Bioinformatics paper Constructing A Semantic Predication Gold Standard from the Biomedical Literature.
Annotator A: Main Phase (main_A.xml) (1.3 mb)
Annotator B: Main Phase (main_B.xml) (1.4 mb)
Annotator C: Adjudication (adjudicated.xml) (1.4 mb)
DTD file (annotations.dtd) (1.8 kb)
In order to develop and evaluate a sortal anaphora resolution module, we annotated a corpus of 320 MEDLINE citations with pairwise sortal anaphora relations consisting of the anaphoric expressions and their correspondent antecedents. Since we aimed at a general approach that takes into account all the semantic types and consequently supports SemRep, we collected MEDLINE abstracts on a wide range of topics, including molecular biology and clinical medicine.
For further details, please refer to our BMC Bioinformatics paper Sortal anaphora resolution to enhance relation extraction from biomedical literature.
Sortal Anaphora dataset:
Sortal Anaphora Dataset
Biomedical knowledge claims are often expressed with extra-propositional entities such as hypotheses, speculations, or opinions, rather than explicit facts (assertions or propositions). Currently, SemRep extracts propositional content in the form of predications. We studied the feasibility of incorporating extra-propositional information by assessing the factuality level of SemRep predications. To this end, we annotated semantic predications extracted from 500 PubMed abstracts with seven factuality values (FACT, PROBABLE, POSSIBLE, DOUBTFUL, COUNTERFACT, UNCOMMITTED, and CONDITIONAL).
For further details, please refer to our PLoS ONE paper Assigning factuality values to semantic relations extracted from Biomedical Research Literature.