Shares of American Science and Engineering, Inc. (Nasdaq: ASEI) are treading lower in pre-market trading after the developer of X-ray and inspection products for homeland security markets reported fiscal fourth-quarter revenue and earnings after Tuesday’s close that declined from the year-ago period and fell substantially short of the consensus on Wall Street. The Billerica, Mass.-based firm said the earnings decline is due to lower gross margins attributable to product mix and an 85% increase in research and development expense.

Shares slipped 14%, or $6.81, to $42.25 in pre-market trading. For detailed price information and recent news stories about American Science and Engineering, click ASEI.