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Researchers seek methods to levitate matter for a wide variety of purposes, ranging from exploring fundamental problems in science, through to developing new sensors and mechanical actuators. Many levitation techniques require active driving and most can only be applied to objects smaller than a few micrometers. Diamagnetic levitation has the strong advantage of being the only form of levitation which is passive, requiring no energy input, while also supporting massive objects. Known diamagnetic materials which are electrical insulators are only weakly diamagnetic, and require large magnetic field gradients to levitate. Strong diamagnetic materials which are electrical conductors, such as graphite, exhibit eddy damping, restricting motional freedom and reducing their potential for sensing applications. In this work we describe a method to engineer the eddy damping while retaining the force characteristics provided by the diamagnetic material. We study, both experimentally and theoretically, the motional damping of a magnetically levitated graphite plate in high vacuum and demonstrate that one can control the eddy damping by patterning the plate with through-slots which interrupt the eddy currents. We find we can control the motional quality factor over a wide range with excellent agreement between the experiment and numerical simulations., 7 pages main + 4 supplementary

We report measurements of the anisotropic thermopower in the normal state of YBa 2 Cu 3 O 7 − δ thin films with three different orientations: a -axis perpendicular to the plane of the substrate; c -axis perpendicular; and coherently tilted on a (305) SrTiO 3 substrate respectively. We have also measured the thermopower of magnetically aligned YBa 2 Cu 3 O 7 − δ ceramic samples. The thermopower in the direction of the c -axis is found to be positive and increases as the temperature increases. The thermopower along the b -axis direction has only a small temperature dependence, while the averaged thermopower in the ab -plane in c -axis films decreases as temperature increases. These results are consistent with those made on single crystals.

Murine corneal aldehyde dehydrogenase has been purified to homogeneity and characterized with a range of aldehyde substrates at pH 7.4. The enzyme was a dimer with a subunit molecular weight of 59 KDa. and appears to prefer aldehyde products of lipid peroxidation as substrates. The enzyme constituted approximately 5% of the total soluble protein of mouse cornea. A dual role has been proposed for corneal aldehyde dehydrogenase in providing the eye with protection against UV-B light: by oxidizing aldehydes generated through light-induced lipid peroxidation; and by the direct absorption of UV-B light by the enzyme.

We present the thermopower (TEP) within the ab plane and c axis of magnetically aligned YBa 2 Cu 3 O 7−δ ceramics with different oxygen contents. For the sample with almost fully loaded oxygen content ( δ = 0.05), TEP exhibits strong anisotropy, namely, the ab -plane TEP behaves distinctly from that along the c axis. The ab -plane TEP bears remarkable similarities to that of the b -axis in an untwinned YBa 2 Cu 3 O 7−δ ( δ = 0.08) single crystal. The c -axis TEP is nearly identical to that of a twinned YBa 2 Cu 3 O 7−δ single crystal. These measurements make available the anisotropic property measurements of ceramic samples by aligning polycrystallites using magnetic forces.

During the three years 1967-69, 781 cases of squamous cell carcinoma of the skin were reported to the Manchester Regional Cancer Registry. The proportions of males to females were significantly different (p

The preparation is described of 4,4′-bipyridylium salts bearing aryl substituents α to one of the heterocyclic nitrogen atoms. Evidence from u.v. and n.m.r. spectra suggests that in the quaternary salts the aryl groups are prevented from assuming co-planarity with the bipyridyl nucleus by the steric effect of the N-methyl group. The compounds were inactive in herbicide tests.

The preparation of the 1,1′-diamino-4,4′-bipyridylium dication is described. In alkaline solution, this gives a product believed to be a nitrogen betaine derived by loss of a proton.