Iranian Journal of Science and Technology, Transaction A, Science (ISTT) is devoted to significant original research articles of moderate length (not more than 15 pages in the ISTT format), in a broad spectrum of Biology, Chemistry, Geology, Mathematics, and Physics. Special attention will be paid to applications of these fields in medical science and multidisciplinary research. Invited surveys of scientific developments in a subject of current interest are occasionally published in ISTT. ISTT is divided into five sections, which are listed below with their subjects of interest.