The Use of a Magnetic Field and Magnetic Force as a Means to Improve the Quality of Protein Crystals - Molecules: Nucleation, Aggregation and Crystallization - page 218

evaluated by X-ray topography and the results demonstrated that crystals
grown in the levitated state were free from internal stress.
Another recent development includes the use of a permanent magnet,
instead of the much larger superconducting magnet, for magnetic levita-
tion using the magneto-Archimedes effect (Maki, Ataka, 2007).
Convection Suppression or Damping in the
Presence of Magnetic Force
To evaluate the potential of using magnetic force, and also to evaluate the
desirable mode of using it, we carried out a numerical simulation to study
how convection can be suppressed or damped in the presence of inhomoge-
neous magnetic fields. Such a study was systematically carried out and doc-
umented in a topic by Ozoe (2005). Two of the initial works that led to
systematic studies are Qi et al . (2001) and Ramachandran and Leslie (2005).
Our simulation has added to the body of work described in Ozoe's Book.
It has been shown that when a diamagnetic liquid is placed in the pres-
ence of upward magnetic force, convection is generally suppressed. The
particular magnetic force distributions we have studied include: a hori-
zontally-directed bore of a superconducting magnet (Maki, Ataka, 2004),
and off-centered positions in a vertically-directed bore (Maki, Ataka,
2005). It was shown that even the convection of water in a vessel placed
at the center of a magnet can be influenced by the realistic magnetic force
that results from the distribution of the magnetic field (Maki, Ataka, 2005).
Recent meaningful progress has been demonstrated by the elucidation
of the difference in the conditions that lead to convection suppression and
those that lead to levitation (Wakayama, 2005; Poodt et al ., 2005).
Summary
A general means to improve the quality of protein crystals is worth devel-
oping, especially as an alternative or a supplement to microgravity exper-
iments in space. Superconducting as well as permanent magnets can be
considered. The use of magnetic orientation is one possibility that has