A 1000-W UV radiation (UVR) source (Lightning
Cure 200, Hamamatsu, Japan) was used for delivering
solar-simulated radiation to pig skin. The lamp
was combined with a dichroic mirror assembly reflecting
most of the visible and infrared emission, to
reduce the heat load on the skin, and with a 1-mm
WG295 Schott selective UVB band-pass filter (295
nm) to eliminate wavelengths less than 295 nm. A
1-cm diameter liquid light guide was connected to
the exit port of the lamp housing to deliver energy to
the surface of the skin. The light guide was positioned
just above the surface of the skin. The intensity
used in the experiment was 5 mW/cm2 of UVB
as measured by a research radiometer (IL1700, International
Light, Newburyport, Mass). At this irradiance,
there was about 40 mW/cm2 of UVA; because
of the much greater erythemal effectiveness of UVB,
the latter is expected to be the dominant wave band
in the observed biologic effects.