Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.

Question: Do antibodies to trophoblast antigens HLA-G , placenta growth factor , and neuroD2 improve detection of circulating trophoblast cells in maternal blood?
Answer: The antibodies used in this study were unable to improve detection of trophoblast cells in the maternal circulation.
no