Abstract: An information retrieval method includes obtaining Mi (i+1)th-hop candidate documents based on a retrieval text query and Ki ith-hop candidate documents; obtaining a score of each candidate document in the Mi (i+1)th-hop candidate documents; obtaining, based on a score of a candidate document Pjy(i+1) and a probability of a path L, a probability of a path corresponding to the candidate document Pjy(i+1); obtaining K(i+1) (i+1)th-hop candidate documents based on probabilities of paths respectively corresponding to the Mi (i+1)th-hop candidate documents; and obtaining, based on the K(i+1) (i+1)th-hop candidate documents, a retrieval result corresponding to the query.

Abstract: The invention relates to a method for enriching a target polynucleotide sequence containing a genetic variation said method comprising: (a) providing two primers targeted to said target polynucleotide sequence; (b) providing a target specific xenonucleic acid clamp oligomer specific for a wildtype polynucleotide sequence; (c) generating multiple amplicons using PCR under specific temperature cycling conditions; and (d) detecting said amplicons. We introduce a novel molecule, Xenonucleic Acid (XNA) for the NGS library preparation. XNA is able to selectively suppress amplification of DNA with wild type alleles and amplify DNA containing mutant alleles. Mutants with low allelic frequency will be easily detectable without deep sequencing after enrichment by adding XNA in multiplex PCR. The 17 actionable mutants related to lung or colorectal cancer diseases at different variant allelic frequency (VAF) % were investigated. Clinical sensitivity is significantly improved with XNA in various types of samples.

Abstract: The invention relates to a method for enriching a target polynucleotide sequence containing a genetic variation said method comprising: (a) providing two primers targeted to said target polynucleotide sequence; (b) providing a target specific xenonucleic acid clamp oligomer specific for a wildtype polynucleotide sequence; (c) generating multiple amplicons using PCR under specific temperature cycling conditions; and (d) detecting said amplicons. We introduce a novel molecule, Xenonucleic Acid (XNA) for the NGS library preparation. XNA is able to selectively suppress amplification of DNA with wild type alleles and amplify DNA containing mutant alleles. Mutants with low allelic frequency will be easily detectable without deep sequencing after enrichment by adding XNA in multiplex PCR. The 17 actionable mutants related to lung or colorectal cancer diseases at different variant allelic frequency (VAF)% were investigated. Clinical sensitivity is significantly improved with XNA in various types of samples.