University of California at Irvine researchers Peter Burke and William Tang were recently awarded a $300,000 grant from the Defense Advanced Research Projects Agency (DARPA) to develop high-frequency electronic devices based on nanotubes, a new type of wire made of carbon and measuring just a few atoms in thickness. They said the research could lead to products such as extremely small, inexpensive, power-efficient wireless networking systems on a single chip, nanobiotechnology developed for biomedical uses (biosensors) and environmental monitoring applications. The project work will take place at UCI's Integrated Nanosystems Research Facility in The Henry Samueli School of Engineering.   . . .    A new company in Oxfordshire, England, makes high-quality ultrahigh vacuum (UHV) deposition components and systems. MANTIS Deposition's products include nanocluster deposition, radiofrequency (RF) atom and RF ion sources, e-beam evaporators, k-cells and thermal gas crackers.   . . .   OSI Systems Inc.'s Security Group has received several orders for conventional x-ray screening and explosives detection systems. The orders, worth approximately $2.2 million, are from several government and commercial customers in the Middle East. Shipments will begin immediately and are scheduled for completion by the end of September. OSI Systems, based in Hawthorne, Calif., develops optoelectronic-based components and systems.