Stimulated Brillouin scattering in dispersed graphene.

We explored the Stimulated Brillouin scattering (SBS) behavior of a transparent liquid containing a low concentration of strongly absorbing nanoparticles. We measured SBS energies in N-methyl-2-pyrrolidone (NMP) and water at 532 nm-wavelength. The previously unknown NMP Brillouin gain factor is gB = 18.6 ± 1.8 cm⋅GW-1. Graphene nanoflakes suspended in liquids strongly quench SBS. Linear dependence of the SBS-threshold on the graphene absorption coefficient (concentration) makes it suitable for the detection of small nanoparticles quantities in water, with a minimal detectable concentration of 5⋅10-8 g⋅cm-3. The effect is interpreted as an antagonism between electrostriction and thermal expansion, which is induced by the formation of carbon vapor bubbles. It is very sensitive to changes in density, refractive index and acoustic absorption coefficient, which parameters can be determined in the SBS method, including access to the bubbling nanosecond dynamics. SBS suppression may find applications in laser technologies and optical telecommunication networks.

Photodynamic inactivation of enveloped virus in protein plasma preparations by solid-phase fullerene-based photosensitizer.

BACKGROUND: The problem of transfusion-transmitted infections still remains serious and actual for health care despite the detailed testing of donors. Human immunodeficiency virus, hepatitis B and C viruses and human cytomegalovirus are among the most dangerous pathogens that can be transmitted with blood. Previously, a composition consisting of fullerene layer applied on silica gel particles was shown to inactivate influenza virus up to complete loss of infectivity. METHODS: In the present study the unit has been developed with source of irradiation whose spectrum is appropriate for solid-phase fullerene. The ability of the unit to inactivate the enveloped influenza virus in protein fraction of donor blood has been studied. RESULTS: It was shown that at optimized conditions complete inactivation of enveloped virus of extremely high initial titer (7.0-9.5 log 10 EID 50/0.2 mL) in the solution of albumin was achieved after as short time as 30 min of irradiation. This process did not affect the oxidative metabolism of neutrophils and membranes of erythrocytes evaluated by NBT reduction test and morphological analysis of erythrocytes, respectively. CONCLUSION: The data obtained suggests that the method described can be recommended for further development and optimization of the procedure of inactivation of viruses in the preparations of the plasma of donor blood.