Semantic Querying of News Articles With Natural Language Questions

The heterogeneity and the increasing amount of the news published on the web create challenges in accessing them. In the authors' previous studies, they introduced a semantic web-based sports news aggregation system called BKSport, which manages to generate metadata for every news item. Providing an intuitive and expressive way to retrieve information and exploiting the advantages of semantic search technique is within their consideration. In this paper, they propose a method to transform natural language questions into SPARQL queries, which could be applied to existing semantic data. This method is mainly based on the following tasks: the construction of a semantic model representing a question, detection of ontology vocabularies and knowledge base elements in question, and their mapping to generate a query. Experiments are performed on a set of questions belonging to various categories, and the results show that the proposed method provides high precision.

In vitro metabolism of isaxonine phosphate: formation of two metabolites, 5-hydroxyisaxonine and 2-aminopyrimidine, and covalent binding to microsomal proteins

Isaxonine phosphate or Nerfactor (2-isopropylaminopyrimidine) has been implicated in several cases of hepatitis which is reversible after withdrawal of the drug. In order to understand the cause of such hepatitis, the metabolic activation of isaxonine phosphate with different liver microsomes was investigated. The major metabolites were 5-hydroxyisopropylaminopyrimidine and 2-aminopyrimidine. Covalent binding to microsomal proteins was also detected. In vitro metabolic activation required intact microsomes, NADPH and O2 as cofactors and was cytochrome P-450 dependent. A sensitive fluorimetric assay of 5-hydroxyisaxonine was developed. The metabolism of isaxonine phosphate was compared in liver microsomes from rat, rabbit, dog, monkey and man and found to be qualitatively similar. Treatment of rats with phenobarbital increased the formation of 5-hydroxyisaxonine, while treatment with 3-methylcholanthrene increased the formation of 2-aminopyrimidine but decreased that of 5-hydroxyisaxonine. Inhibition and reconstitution experiments demonstrated that 5-hydroxylation of isaxonine was catalyzed by a cytochrome P-450. Metabolic oxidation of isaxonine phosphate using 5-[3H]isaxonine phosphate led to a total loss of tritium in 5-hydroxyisaxonine and partial loss of tritium in 2-aminopyrimidine and covalent binding to proteins.