A double-injection field-effect transistor has an anode, a cathode, a substantially transparent channel, a substantially transparent gate insulator, and at least one substantially transparent gate electrode. The shaped body contains at least one dye precursor, at least one oxidizing agent, and at least one alkalinizing agent. An extension wiring which is formed by partially extending from the crossing area along a wiring extending direction of other power supply wiring is provided at least to either the first power supply wiring or the second power supply wiring. Also provided are methods for detecting angiogenesis, tumorous tissue, metastases, and tumor invasion into a tissue by contacting a composition of the invention with a tissue and methods for screening compositions of the invention. Significantly, the entire tradeshow booth is extremely lightweight and strong, and may be assembled entirely by hand without using tools of any kind. An absorptive filter is aligned such that the angle of incidence of the light beam upon the filter approximates Brewster’s angle and the electric field vector of the beam is aligned with the plane of incidence between the beam and the filter.