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The paramagnetic fluid composed of manganese chloride tetrahydrate dissolved in water was used to form bridges held between two parallel collinear rods. Magnetic levitation was used to control the effective gravity felt by the bridges. Their stability was studied as a function of Bond number and volume of the supported liquid. Data are compared with theoretical predictions for liquid bridges as well as with experimental results, where available. Copyright 1999 Academic Press.

The orientational relaxation of the magnetotactic bacterium Aquaspirillum magnetotacticum is observed by the decay of the optical birefringence upon switching off an aligning magnetic field. The data yield a rotational diffusion constant D(r) [unk] 0.13 s(-1) and information about cell sizes that is consistent with optical microscopy data.

The polymerizable diacetylenic phospholipid 1,2-bis(10,12,tricosadiynoyl)-sn-glycero-3-phosphocholine (DC(23)PC) forms straight hollow cylinders in water. Using an ac electric field it was possible to achieve significant orientational alignment of the tubules parallel to the field direction, and from light scattering results deduce an effective dielectric susceptibility anisotropy Deltachi(E). Moreover, we suggest that the alignment arises from an orientational anisotropy of the total electrostatic enthalpy for a dielectric tubule in an electric field, rather than an inherent polarizability anisotropy of the constituent DC(23)PC molecules, as was the case with magnetic field alignment.

A birefringence technique is used to determine the average magnetic moments of magnetotactic bacteria in culture. Differences in are noted between live and dead bacteria, as well as between normal density and high density samples of live bacteria.