Microstructures in 3D Biological Gels Affect Cell Proliferation

A balun and method for electrically connect a twisted pair cable (2) to a coaxial cable (3) are disclosed. The twisted pair cable (2) has two active wires (4, 5), an earthing wire (6) and shielding (7). The balun includes a hollow conductive cover (8) defining first and second apertures (9, 10); the first aperture (9) being sized to accept the twisted pair cable (2). The cover (8), when in use, houses an earthing means (11) for electrically connecting the earthing wire (6) and/or shielding (7) to the cover (8). The cover, when in use, further houses first mounting means (12) adapted to mount the active wires (4, 5) in close proximity to the second aperture (10); and a body (13) housing second mounting means (14) adapted to mount a pair of first connectors (15, 16) projecting from the body. The body further houses a first transformer (17) electrically connected to the first connectors (15, 16). An end of the body (13) defines a coaxial connector (18) electrically connected to the first transformer (17), whereby the cover (8) is mountable to the body such that an earthing connection is made therebetween, and such that the first connectors (15, 16) respectively electrically connect with the active wires (4, 5), thereby completing an impedance matching electrical circuit between the twisted pair cable (2) and the coaxial cable connector (18).