Effect of a high magnetic field on the viscosity of an aqueous solution ofprotein

The effect of a uniform magnetic field of 10 T on the viscosity of aqueous protein solutions was studied, using two kinds of the solution. When the so lution was prepared for crystals not to be easily formed therein and it con tained unsolved small crystals, the viscosity increased when a magnetic fie ld of 10 T was applied and it returned to its initial value after shutting off the magnetic field. This phenomenon was explained by the magnetic orien tation of small crystals suspended in the solution. On the other hand, when the solution was prepared in which crystals are easily formed, the viscosi ty increased with time of applying a field of 10 T. When the field of 10 T was applied for 3 h on this solution, the viscosity did not return to its i nitial value after shutting off the magnetic field. This experimental resul t suggests that the application of 10 T for a long time might affect the st ructure of this type of solution. The improvement of crystal quality and th e decrease of crystal growth rate under high magnetic fields can be explain ed by the damping of natural convection caused by these two kinds of magnet ically induced increase of viscosity. (C) 2001 Elsevier Science B.V. All ri ghts reserved.