This means that {TAIL ~ the nanoparticles} replace a certain percentage of {HEAD ~ the microparticles}, which causes a reduction of the viscosity  
This means that { TAIL ~ the nanoparticles } replace a certain percentage of { HEAD ~ the microparticles } , which causes a reduction of the viscosity
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH