The process of mitosis is a validated point of intervention in cancer therapy and a variety of anti-mitotic drugs are successfully being used in the clinic. To date, all approved antimitotics target the spindle microtubules, thus interfering with spindle dynamics, leading to mitotic arrest and apoptosis. While effective, these drugs are also associated with a variety of side effects, including neurotoxicity. In recent years, mitotic kinesins have attracted significant attention in the search for novel, alternative mitotic drug targets. Due to their specific function in mitosis, targeting these proteins creates an opportunity for the development of more selective antimitotics with an improved side effect profile. In addition, kinesin inhibitors may overcome resistance to microtubule targeting drugs. Drug discovery efforts in this area have initially focused on the plus-end directed kinesin spindle protein (KSP) and a variety of compounds are currently undergoing clinical testing.

Nature © Macmillan Publishers Ltd 1998 8 letters to nature 566 NATURE | VOL 391 | 5 FEBRUARY 1998X-ray microprobe, our CRL could be used to guide and focus the neutron beam to explore local crystallography and magnetic domains. In addition, two other uses are possible. The first is to reduce neutron beam divergence and enhance the resolution limit of Bragg reflection rocking curves. The second possibility would be to magnify the pattern of scattered neutrons from a sample. Because area detectors for neutrons have a relatively low spatial resolution (5 mm), small-angle experiments use long (up to 40 m), expensive, evacuated paths to spread the diffraction pattern over the detector. Magnifying optics could be used to shorten this flight path. We are at present exploring new materials and achromatic lens designs. Such a system could provide significant new opportunities for the present generation of reactor-based neutron sources.

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In this paper we investigate the effect that the quality of the gold substrate has upon the distribution of adhesion force measurements in chemical force microscopy. Gold samples have been prepared by two protocols which give either predominantly single-crystal Au(111) or polycrystalline gold films on mica. Gold-coated tips and surfaces were functionalized with self-assembled monolayers terminating in carboxylic groups, and more that 500 force-distance plots were taken. Analysis of these plots revealed a 50% narrower distribution of adhesion forces between monolayers prepared on single-crystal surfaces and monolayers prepared on polycrystalline gold, when measurements were repeated at a single point. However when measurements were taken over a 1-μm area, the distribution of adhesion forces was similar for both samples. An explanation for this may lie in the size of the domains on the gold surface relative to the contact area of the tip.

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