The fluid containing {HEAD ~ the photosensitizer} may be flowed into a photopermeable container for {TAIL ~ irradiation} 
The fluid containing { HEAD ~ the photosensitizer } may be flowed into a photopermeable container for { TAIL ~ irradiation }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL