Materials technology group Morgan Advanced Materials (MAM) said that trading remains in line with expectations at the start of the year warned that a currency headwinds could dampen full-year results.The company, whose products range from medical instruments to body armour, said that year-to-date revenues have been broadly flat on last year on a constant currency basis and adjusting for business lines that have been sold or exited.Conditions in end markets remain mixed, Morgan said, but it had a positive book-to-bill ratio of 1.08 by the end of April and an "outstanding" order book 5% higher than last year at constant currency, with Asia showing the most improvement.However, the company said that the strength in sterling since the start of the 2014 against the majority of currencies in which it trades has had an impact on results."If these exchange rates persist through the year the translational effect would reduce our reported revenue by circa 5-6% when compared to the previous year's reported results," Morgan said.The stock was 0.15% lower at 337p by 08:30 on Friday.BC